TSI Instruments 3772, 3771 Operation And Service Manual

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Model 3772

Model 3771

(discontinued)

CONDENSATION

PARTICLE COUNTER

MODEL 3772/3771

OPERATION AND SERVICE MANUAL

P/N 1980529, REVISION F

APRIL 2015

CONDENSATION

PARTICLE COUNTER

MODEL 3772/3771

OPERATION AND SERVICE MANUAL

Product Overview

Unpacking and Setting Up the CPC

Instrument Description

Instrument Operation

Technical Description

Particle Counting

Computer Interface and Commands

Maintenance and Service

Appendixes

Manual History

The following is a history of the Model 3772/3771 Condensation Particle Counter Operation and Service Manual (Part Number 1980529).

Revision Date

A February 2006 B April 2006 C April 2007 D December 2009 E July 2011 F April 2015

Warranty

Part Number

1980529 / Revision F / April 2015

Address

TSI Incorporated / 500 Cardigan Road / Shoreview, MN 55126 / USA

Fax No.

651-490-3824

E-mail Address

particle@tsi.com

Limitation of Warranty and Liability

(effective February 2015)

Seller warrants the goods, excluding software, sold hereunder, under normal use and service as described in the operator's manual, to be free from defects in workmanship and material for 12 months, or if less, the length of time specified in the operator's manual, from the date of shipment to the customer. This warranty period is inclusive of any statutory warranty. This limited warranty is subject to the following exclusions and exceptions:

a. Hot-wire or hot-film sensors used with research anemometers, and certain other components

when indicated in specifications, are warranted for 90 days from the date of shipment; b. Pumps are warranted for hours of operation as set forth in product or operator’s manuals; c. Parts repaired or replaced as a result of repair services are warranted to be free from defects

in workmanship and material, under normal use, for 90 days from the date of shipment; d. Seller does not provide any warranty on finished goods manufactured by others or on any

fuses, batteries or other consumable materials. Only the original manufacturer's warranty

applies; e. This warranty does not cover calibration requirements, and seller warrants only that the

instrument or product is properly calibrated at the time of its manufacture. Instruments

returned for calibration are not covered by this warranty; f. This warranty is VOID if the instrument is opened by anyone other than a factory authorized

service center with the one exception where requirements set forth in the manual allow an

operator to replace consumables or perform recommended cleaning; g. This warranty is VOID if the product has been misused, neglected, subjected to accidental

or intentional damage, or is not properly installed, maintained, or cleaned according to the

requirements of the manual. Unless specifically authorized in a separate writing by Seller,

Seller makes no warranty with respect to, and shall have no liability in connection with, goods

which are incorporated into other products or equipment, or which are modified by any person

other than Seller. The foregoing is IN LIEU OF all other warranties and is subject to the LIMITATIONS stated

herein. NO OTHER EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR PARTICULAR

PURPOSE OR MERCHANTABILITY IS MADE. WITH RESPECT TO SELLER’S BREACH OF THE IMPLIED WARRANTY AGAINST INFRINGEMENT, SAID WARRANTY IS LIMITED TO CLAIMS OF DIRECT INFRINGEMENT AND EXCLUDES CLAIMS OF CONTRIBUTORY OR

INDUCED INFRINGEMENTS. BUYER’S EXCLUSIVE REMEDY SHALL BE THE RETURN OF

THE PURCHASE PRICE DISCOUNTED FOR REASONABLE WEAR AND TEAR OR AT SELLER’S OPTION REPLACEMENT OF THE GOODS WITH NON-INFRINGING GOODS.

TO THE EXTENT PERMITTED BY LAW, THE EXCLUSIVE REMEDY OF THE USER OR BUYER, AND THE LIMIT OF SELLER'S LIABILITY FOR ANY AND ALL LOSSES, INJURIES, OR DAMAGES CONCERNING THE GOODS (INCLUDING CLAIMS BASED ON CONTRACT, NEGLIGENCE, TORT, STRICT LIABILITY OR OTHERWISE) SHALL BE THE RETURN OF GOODS TO SELLER AND THE REFUND OF THE PURCHASE PRICE, OR, AT THE OPTION OF SELLER, THE REPAIR OR REPLACEMENT OF THE GOODS. IN THE CASE OF SOFTWARE, SELLER WILL REPAIR OR REPLACE DEFECTIVE SOFTWARE OR IF UNABLE TO DO SO, WILL REFUND THE PURCHASE PRICE OF THE SOFTWARE. IN NO EVENT SHALL SELLER BE LIABLE FOR LOST PROFITS, BUSINESS INTERRUPTION, OR ANY SPECIAL, INDIRECT, CONSEQUENTIAL OR INCIDENTAL DAMAGES. SELLER SHALL NOT BE RESPONSIBLE FOR INSTALLATION, DISMANTLING OR REINSTALLATION COSTS OR CHARGES. No Action, regardless of form, may be brought against Seller more than 12 months after a cause of action has accrued. The goods returned under warranty to Seller's factory shall be at Buyer's risk of loss, and will be returned, if at all, at Seller's risk of loss.

Buyer and all users are deemed to have accepted this LIMITATION OF WARRANTY AND LIABILITY, which contains the complete and exclusive limited warranty of Seller. This LIMITATION OF WARRANTY AND LIABILITY may not be amended, modified or its terms waived, except by writing signed by an Officer of Seller.

Service Policy

Knowing that inoperative or defective instruments are as detrimental to TSI as they are to our customers, our service policy is designed to give prompt attention to any problems. If any mal-

function is discovered, please contact your nearest sales office or representative, or call TSI’s

Customer Service department at 1-800-874-2811 (USA) or (651) 490-2811.

Trademarks

Scanning Mobility Particle Sizer and SMPS are trademarks of TSI Incorporated. Aerosol Instrument Manager is a registered trademark of TSI Incorporated. Microsoft and Windows are registered trademarks of Microsoft Corporation.

vi Model 3772/3771 Condensation Particle Counter

Laser Safety

W A R N I N G

The use of controls, adjustments, or procedures other than those

specified in this manual may result in exposure to hazardous optical radiation.

Safety

This section provides instructions to ensure safe and proper operation and handling of the Model 3772/3771 Condensation Particle Counter (CPC).

There are no user-serviceable parts inside the instrument. Refer all repair and maintenance to a qualified technician. All maintenance and repair information in this manual is included for use by a qualified technician.

The Model 3772/3771 CPC is a Class I laser-based instrument. During normal operation, you will not be exposed to laser radiation. However, you must take certain precautions or you may expose yourself to hazardous radiation in the form of intense, focused visible light. Exposure to this light can cause blindness.

Take these precautions:  Do not remove any parts from the CPC unless you are specifically told

to do so in this manual.

 Do not remove the CPC housings or covers while power is supplied to

the instrument.

Chemical Safety

The Model 3772/3771 CPC uses n-butyl alcohol (butanol) as a working fluid. Butanol is flammable. Butanol is also toxic if inhaled. Refer to a Material Safety Data Sheet for butanol and take these precautions:

 Use butanol only in a well-ventilated area. Under normal operating

conditions butanol is exhausted into the air at approximately 0.015 g per minute.

 Butanol vapor is identified by its characteristically strong odor and can

easily be detected. If you smell butanol and develop a headache, or feel faint or nauseous, leave the area at once. Ventilate the area before returning.

vii

C a u t i o n

Butanol is flammable. Butanol is also potentially toxic if inhaled. Use

butanol only in a well-ventilated area. If you smell butanol and develop a headache, or feel faint or nauseous, leave the area at once. Ventilate the area before returning.

W A R N I N G

Although the CPC is appropriate for monitoring inert process gases such

as nitrogen or argon, it should not be used with hazardous gases such as hydrogen or oxygen. Using the CPC with hazardous gases may cause injury to personnel and damage to equipment.

C a u t i o n

Caution means be careful. It means if you do not follow the procedures

prescribed in this manual you may do something that might result in equipment damage, or you might have to take something apart and start over again. It also indicates that important information about the operation and maintenance of this instrument is included.

W A R N I N G

Warning means that unsafe use of the instrument could result in serious

injury to you or cause irrevocable damage to the instrument. Follow the procedures prescribed in this manual to use the instrument safely.

Description of Safety L a bels

This section acquaints you with the advisory and identification labels on the instrument and used in this manual to reinforce the safety features built into the design of the instrument.

Caution

Warning

viii Model 3772/3771 Condensation Particle Counter

Caution or Warning Symbols

Warns you that uninsulated voltage within the instrument may have sufficient magnitude to cause electric shock. Therefore, it is dangerous to make any contact with any part inside the instrument.

Warns you that the instrument contains a laser and that important information about its safe operation and maintenance is included. Therefore, you should read the manual carefully to avoid any exposure to hazardous laser radiation.

Warns you that the instrument is susceptible to electro-static dissipation (ESD) and ESD protection procedures should be followed to avoid damage.

Indicates the connector is connected to earth ground and cabinet ground.

1. Serial Number label – displayed on the back panel

2. Laser Radiation label – located internally on the optics housing

3. Electrical shock caution label – displayed on back panel

4. Laser device compliance label – displayed on back panel

The following symbols may accompany cautions and warnings to indicate the nature and consequences of hazards:

Labels

Advisory labels and identification labels are attached to the outside of the CPC housing and to the optics on the inside of the instrument. Labels for the Model 3772/3771 CPC are described below:

Safety ix

5. Caution label

6. European Recycling Label – displayed on the back panel (indicates item is nondisposable and must be recycled).

7. French language electrical

safety and laser compliance labels – displayed on the back

panel

8. NRTL TÜV SÜD Mark – displayed on the back panel. This mark identifies the product as meeting safety regulations in the US, Canada and Europe and further identifies the product as one for which ongoing production is monitored for quality.

9. TSI Address and Service Label – displayed on the back panel

10. Saturator Wick Removal caution label – displayed on the bottom of the enclosure

x Model 3772/3771 Condensation Particle Counter

Manual History ........................................................................................... iv

Warranty ...................................................................................................... v

Safety ......................................................................................................... vii

Laser Safety ......................................................................................... vii

Chemical Safety ................................................................................... vii

Description of Safety Labels ................................................................ viii

Caution .............................................................................................. viii

Warning ............................................................................................. viii

Caution or Warning Symbols ............................................................. ix

Labels .................................................................................................... ix

About This Manual ................................................................................. xvii

Purpose ............................................................................................... xvii

Organization ........................................................................................ xvii

Related Product Literature ................................................................. xviii

Submitting Comments ......................................................................... xix

CHAPTER 1 Product Overview .............................................................. 1-1

Product Description ............................................................................. 1-1

How it Works ....................................................................................... 1-2

CHAPTER 2 Unpacking and Setting up the CPC ................................. 2-1

Packing List ......................................................................................... 2-1

Unpacking ........................................................................................... 2-2

Setting Up ........................................................................................... 2-3

Remove Protective Caps ................................................................. 2-3

Mounting the Bracket and Fill Bottle ................................................ 2-3

Filling the Fill Bottle with Butanol ..................................................... 2-4

Connecting the Butanol Drain Bottle ............................................... 2-4

Apply Power to the CPC .................................................................. 2-4

Supply External Vacuum to the CPC ............................................... 2-5

Positioning the CPC ......................................................................... 2-5

CHAPTER 3 Instrument Description ...................................................... 3-1

Model 3772 Front Panel ...................................................................... 3-1

LCD Display and Keypad ................................................................. 3-1

Aerosol Inlet ..................................................................................... 3-2

Status Light ...................................................................................... 3-2

Particle Light .................................................................................... 3-2

Flash Memory Card Slot .................................................................. 3-2

Model 3771 Front Panel ...................................................................... 3-3

Model 3772/3771 Back Panel ............................................................. 3-3

AC Connector and Switch ................................................................ 3-3

USB Communication Port ................................................................ 3-3

RS-232 Serial Connections ............................................................. 3-4

Analog Inputs ................................................................................... 3-5

DMA/Analog Output and Pulse Output ............................................ 3-5

Ethernet Communication Port.......................................................... 3-6

Butanol Fill Port ............................................................................... 3-6

External Vacuum Port ...................................................................... 3-6

Drain Port ........................................................................................ 3-7

Instrument Cooling Fan ................................................................... 3-7

Cover .................................................................................................. 3-7

Bottom Panel ...................................................................................... 3-7

Internal Instrument Components ........................................................ 3-8

Water Removal Pump ..................................................................... 3-8

Filters ............................................................................................... 3-9

Valves .............................................................................................. 3-9

Pressure Transducers ..................................................................... 3-9

Electronics Boards ........................................................................... 3-9

Basic Instrument Functions .............................................................. 3-10

Concentration Measurement ......................................................... 3-10

Total Count Mode (3772 only) ....................................................... 3-11

Water Removal .............................................................................. 3-11

Internal Data Logging (3772 only) ................................................. 3-11

Remote Access of Instrument ....................................................... 3-11

External Vacuum Pump or Source ................................................ 3-11

Flow Rate Control .......................................................................... 3-12

Temperature Control ..................................................................... 3-12

Inlet Pressure Measurement ......................................................... 3-12

CHAPTER 4 Instrument Operation ........................................................ 4-1

Operating Precautions ........................................................................ 4-1

Power Switch ...................................................................................... 4-1

Warm-up ............................................................................................. 4-1

Status Indicator ................................................................................... 4-2

Particle Indicator ................................................................................. 4-2

Communication ................................................................................... 4-2

Model 3772 LCD Display and Keypad ............................................ 4-3

Model 3772 Keypad Navigation ...................................................... 4-3

Concentration ..................................................................................... 4-4

Total Count Mode (3772 only) ............................................................ 4-5

User Settings ...................................................................................... 4-5

Data Logging (3772 only) ................................................................ 4-6

Water Removal ................................................................................ 4-6

Totalizer Time (3772 only) ............................................................... 4-7

Auto Fill ............................................................................................ 4-7

Analog Out ....................................................................................... 4-7

Data Averaging (3772 only) ............................................................. 4-8

Drain ................................................................................................ 4-8

Status .................................................................................................. 4-8

Saturator Temp (Temperature) ....................................................... 4-9

Condenser Temp (Temperature) ..................................................... 4-9

Optics Temp (Temperature) ............................................................ 4-9

Cabinet Temp (Temperature) .......................................................... 4-9

Ambient Pressure ............................................................................ 4-9

Orifice Pressure ............................................................................. 4-10

Nozzle Pressure ............................................................................ 4-10

Laser Current ................................................................................. 4-10

Liquid Level ................................................................................... 4-10

Analog Inputs ................................................................................. 4-10

Flash Status (3772 only) ............................................................... 4-10

xii Model 3772/3771 Condensation Particle Counter

USB Status .................................................................................... 4-10

Firmware Version ........................................................................... 4-11

Using the Flash Memory Card (3772 only) ....................................... 4-11

Aerosol Instrument Manager® Software ............................................ 4-13

Moving and Shipping the CPC .......................................................... 4-13

CHAPTER 5 Technical Description ........................................................ 5-1

Theory ................................................................................................. 5-1

History ................................................................................................. 5-2

Adiabatic Expansion CNC ............................................................... 5-2

Two-Flow Mixing CNC ..................................................................... 5-3

Diffusional Thermal CNC ................................................................. 5-3

Design of the CPC .............................................................................. 5-5

Sensor .............................................................................................. 5-5

Critical Flow ..................................................................................... 5-7

Counting Efficiency and Response Time of the 3772/3771 CPC ....... 5-8

CHAPTER 6 Particle Counting ............................................................... 6-1

Optical Detection ................................................................................. 6-1

Total Count Accuracy .......................................................................... 6-2

Live-Time Counting ............................................................................. 6-2

Coincidence Correction for Pulse Output ........................................ 6-3

Particle Size Selector .......................................................................... 6-4

CHAPTER 7 Computer Interface and Commands ................................ 7-1

Computer Interface ............................................................................. 7-1

USB .................................................................................................. 7-1

Ethernet ........................................................................................... 7-1

Flash Memory Card Specification (3772 only) ................................. 7-5

RS-232 Serial Communications ...................................................... 7-6

Commands .......................................................................................... 7-7

CHAPTER 8 Maintenance and Service .................................................. 8-1

Replacement Parts Kits ...................................................................... 8-2

Draining Butanol from the Butanol Reservoir ..................................... 8-4

Changing the Filters ............................................................................ 8-5

Butanol Fill and Drain Filters ............................................................ 8-5

Micro Pump Filter ............................................................................. 8-6

Removing and Installing the Saturator Wick ....................................... 8-7

Verifying Flow Rate ........................................................................... 8-10

Calibration ......................................................................................... 8-10

Correcting Flooded Optics ................................................................ 8-11

Viewing Analog Pulses ..................................................................... 8-12

Calibration Reminder ........................................................................ 8-14

False Count Check ........................................................................... 8-14

Error Messages and Troubleshooting ............................................... 8-15

Technical Contacts ........................................................................... 8-17

Returning the CPC for Service .......................................................... 8-18

APPENDIX A Specifications .................................................................. A-1

APPENDIX B Firmware Commands ...................................................... B-1

READ Commands .............................................................................. B-1

SET Commands ................................................................................. B-5

MISC (MISCELLANEOUS) Commands ............................................ B-8

HELP Commands .............................................................................. B-9

Contents xiii

Figures

APPENDIX C References ....................................................................... C-1

Index

Reader’s Comments Sheet

1-1 Model 3772 Condensation Particle Counter ..................................... 1-2

1-2 Model 3771 Condensation Particle Counter ..................................... 1-2

2-1 View of Fill Bottle Bracket Mounting ................................................. 2-3

3-1 View of the Model 3772 Front Panel ................................................. 3-1

3-2 View of the Model 3771 Front Panel ................................................. 3-3

3-3 Back Panel of the Model 3772/3771 CPC ........................................ 3-4

3-4 Sample Digital Pulse from Pulse Output Port at the Back Panel

of the CPC ........................................................................................ 3-6

3-5 Bottom Panel Showing Removable Saturator Base ......................... 3-7

3-6 Internal Components of the Model 3772/3771 CPC ......................... 3-8

3-7 Electronics Boards inside the Model 3772/3771 CPC .................... 3-10

4-1 Model 3772 Display During Warm-Up .............................................. 4-2

4-2 Model 3772 Display After Warm-Up is Completed ........................... 4-2

4-3 Model 3772 Front Panel LCD Display and Keypad .......................... 4-3

4-4 Total Count Mode Data Screen ........................................................ 4-5

4-5 Initial Total Mode Data Screen .......................................................... 4-5

4-6 User Settings Display ........................................................................ 4-5

4-7 Status Display ................................................................................... 4-9

4-8 Status Parameter Display for Diagnostics ........................................ 4-9

4-9 Reformatting the Flash Memory Card ............................................. 4-12

5-1 Flow Schematic of the Model 3772/3771 CPC ................................. 5-6

5-2 Counting Efficiency Curve of 3772/3771 CPC .................................. 5-8

5-3 Response Time of 3772/3771 CPC ................................................ 5-10

7-1 Digi Device Discovery Screen ........................................................... 7-2

7-2 Configure Network Settings Screen .................................................. 7-3

7-3 Digi Connect ME Configuration and Management Screen ............... 7-3

7-4 Main Screen HTML Page .................................................................. 7-4

7-5 RS-232 Connector Pin Designations ................................................ 7-6

8-1 Vacuum Drain Cap Assembly ........................................................... 8-4

8-2 Replacing the Butanol Fill and Drain Filters ...................................... 8-5

8-3 Replacing the Micro Pump Filter ....................................................... 8-6

8-4 Inlet Tube .......................................................................................... 8-7

8-7 O-Rings on Saturator Base (P/N 2501172 and 2501569) ................ 8-9

8-8 O-Rings on Saturator Base (P/N 2500021) ...................................... 8-9

8-9 Connecting SMC Plug to Detector Board ....................................... 8-13

8-10 Typical Analog Pulse Trace ............................................................ 8-13

xiv Model 3772/3771 Condensation Particle Counter

Tables

2-1 Model 3772 CPC Packing List .......................................................... 2-1

2-2 Model 3771 CPC Packing List .......................................................... 2-2

6-1 Coincidence Levels Based on 0.35 µsec Pulse Width ...................... 6-3

7-1 Signal Connections for RS-232 Configurations ................................ 7-7

8-1 3772/3771 CPC Maintenance and Replacement Kits ....................... 8-2

8-2 Troubleshooting ............................................................................... 8-15

A-1 Model 3772/3771 CPC Specifications ............................................. A-2

Contents xv

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xvi Model 3772/3771 Condensation Particle Counter

Purpose

Organization

About This Manual

This is an operation and service manual for the Model 3772/3771 Condensation Particle Counter (CPC).

The following is a guide to the organization of this manual:  Chapter 1: Product Overview

This chapter gives an introduction to the Model 3772/3771

Condensation Particle Counter, a list of features, and a brief description of how the instrument works.

 Chapter 2: Unpacking and Setting Up the CPC This chapter gives a packing list and the step-by-step procedure for

getting the CPC ready to operate.

 Chapter 3: Instrument Description This chapter describes features and controls that run the CPC,

including the components on the front-panel, back-panel, bottompanel, cover and inside the instrument. It also covers the basic functions of the instrument.

 Chapter 4: Instrument Operation This chapter describes the operation of the instruments.

 Chapter 5: Technical Description This chapter details the principle of operation, theory, and performance

of the condensation nucleus counter.

 Chapter 6: Particle Counting This chapter describes the particle counting modes.

 Chapter 7: Computer Interface and Commands This chapter describes the computer interface hardware, associated

firmware commands, and flash memory card.

 Chapter 8: Maintenance and Service This chapter describes the recommended practices and schedule for

routine cleaning, checking and calibration.

 Appendix A: Specifications This appendix lists the specifications of the Model 3772/3771

Condensation Particle Counter.

xvii

 Appendix B: Firmware Commands

This appendix lists all the serial commands for communications

between the CPC and the computer.  Appendix C: References

This chapter lists all of the references that have been used within the

text of the manual. In addition, a general list of references pertaining to

condensation nucleus counters is included.

Related Product Lite r ature

 Model 3007 Condensation Particle Counter Operation and Service

Manual (part number 1930035) TSI Incorporated  Model 3775 Condensation Particle Counter Operation and Service

Manual (part number 1980527) TSI Incorporated  Model 3776 Ultrafine Condensation Particle Counter Operation

and Service Manual (part number 1980522) TSI Incorporated  Model 3783 EPC™ Environmental Particle Counter™ Monitor

Operation and Service Manual (part number 6003653) TSI

Incorporated

 Model 3785 Water-based Condensation Particle Counter

Operation and Service Manual (part number 1933001) TSI

Incorporated

 Model 3786 Ultrafine Water-based Condensation Particle Counter

Operation and Service Manual (part number 1930072) TSI

Incorporated

 Model 3787 General Purpose Water-based Condensation Particle

Counter Operation and Service Manual (part number 6003712) TSI

Incorporated

 Model 3788 Nano Water-based Condensation Particle Counter

Operation and Service Manual (part number 6003713) TSI

Incorporated  Model 376060 Particle Size Selector Instruction Manual (part

number 1930013) TSI Incorporated

This manual contains operating instructions for the Model 376060

Particle Size Selector, an accessory for the Model 3772, 3771, and

3781 CPCs. The Model 376060 is a separating device that removes

small particles from an aerosol while passing larger particles.

 Aerosol Instrument Manager® Software for CPC and EAD

Instruction Manual (part number 1930062) TSI Incorporated

This manual contains operating instructions for Aerosol Instrument

Manager Software for CPC and EAD, a software program that

monitors, calculates, and displays particle concentration data collected

by a CPC or an EAD.

xviii Model 3772/3771 Condensation Particle Counter

Submitting Comments

TSI values your comments and suggestions on this manual. Please use the comment sheet on the last page of this manual to send us your opinion

on the manual’s usability, to suggest specific improvements, or to report

any technical errors. If the comment sheet has already been used, please mail your comments

on another sheet of paper to:

TSI Incorporated Particle Instruments 500 Cardigan Road Shoreview, MN 55126 Fax: (651) 490-3824 E-mail Address: particle@tsi.com

About This Manual xix

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xx Model 3772/3771 Condensation Particle Counter

C H A P T E R 1

Product Overview

This chapter contains an introduction to the Model 3772/3771 Condensation Particle Counter (CPC) and provides a brief explanation of how the instrument operates.

Product Description

The Model 3772/3771 Condensation Particle Counter is a compact, rugged, and full-featured instrument that detects airborne particles down to 10 nanometers in diameter at an aerosol flow rate of 1.0 liter per minute, over a concentration range from 0 to 104 particles per cubic centimeter. These CPCs are ideally suited for applications that do not require measurement of high concentrations, such as basic aerosol research, filter and air-cleaner testing, particle counter calibration, environmental monitoring, mobile aerosol studies, particle shedding and component testing, and atmospheric and climate studies. The Model 3772 CPC is also compatible with TSI Scanning Mobility Particle SizerTM (SMPSTM) spectrometers for particle size distribution measurements.

The successor to the Model 3010, 3760A, and 3762 CPCs, the Model 3772 and 3771 CPCs offer many new features and improvements:

 Fast response to rapid changes in aerosol concentration (T

seconds)

 Butanol-friendly features, including anti-spill design, water-removal

system, and improved resistance to optics flooding

 Removable saturator wick for easy transport and maintenance  USB and Ethernet available  Auto recovery from power failure

The Model 3772 CPC offers the following additional features:

 Built-in SMPS  Particle concentration, total counts, instrument status or user settings

shown on enhanced front panel LCD display

 Built-in data logging and storage capability with removable memory

card

spectrometer compatibility

 3

1-1

Figure 1-1 Figure 1-2

Model 3772 Condensation Particle Counter Model 3771 Condensation Particle Counter (discontinued)

How it Works

In the Model 3772/3771 Condensation Particle Counter (CPC), an aerosol sample is drawn continuously through a heated saturator in which butanol is vaporized and diffuses into the sample stream. Together, the aerosol sample and butanol vapor pass into a cooled condenser where the butanol vapor becomes supersaturated and ready to condense. Particles present in the sample stream serve as condensation nuclei. Once condensation begins, particles that are larger than a threshold diameter quickly grow into larger droplets and pass through an optical detector where they are counted easily.

The Model 3772/3771 CPC detects particles as small as 10 nanometer in diameter and employs single-particle-count-mode operation to measure concentrations up to 104 particles per cubic centimeter. The detector counts individual pulses produced as each particle (droplet) passes through the sensing zone. A high signal-to-noise ratio and continuous, livetime coincidence correction provide great measurement accuracy, even at very low concentrations. An external vacuum pump is required to draw the

1-2 Model 3772/3771 Condensation Particle Counter

aerosol sample into the CPC. The 1.0 L/min aerosol flow rate is controlled accurately and reliably using an internal critical orifice.

The CPCs use a laser-diode light source and diode photodetector to collect scattered light from particles. An internal microprocessor is used for instrument control and data processing.

Model 3772 CPC has a two-line LCD display which presents real-time number concentration, totalizer function, and enables easy-to-use menus for control operation functions and presents instrument status information and user settings. A variety of communication options for computer data acquisition are available. The 3772 CPC also includes on-board data logging and storage using a removable flash memory card. Model 3771 has no display and no memory card.

Product Overview 1-3

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1-4 Model 3772/3771 Condensation Particle Counter

Packing List

Qty.

Description

Model/ Part Number

Model 3772 CPC and Operation Manual

1980529

Power cable

(based on destination)

Aerosol Instrument Manager® Software

390065

Fill Bottle

1035590

Drain Bottle

1035591

Bottle Bracket

1503475

Vacuum Drain Bottle Cap

1031526

RS-232 Cable (A-pin M/F, 12 ft)

962002

USB I/O Cable A/B 6 ft

1303740

SanDisk ImageMate 5-in-1 Card Reader

1500208

Data Memory Card

1500108

Saturator Wick CPC 3772

1600047

Water Removal Filter Inline, 25 micron 116" barb

1500192

Butanol Fill/Drain Filter Inline, 73 micron 18" barb

1602088

Saturator Base O-Ring FVMQ 1-010

2500021

Saturator Base O-Ring FVMQ 1-030

2501172

Saturator Base O-Ring EPDM 1-027

2501569

Krytox

O-ring Grease

1701154

Checkout Data Sheet

N/A 1 Certificate of Conformance

N/A

C H A P T E R 2

Unpacking and Setting up the CPC

Use the information in this chapter to unpack the Model 3772/3771 Condensation Particle Counter (CPC) and set it up.

Tables 2-1 and 2-2 show the components shipped with the Model 3772 and 3771 CPCs.

Table 2-1

Model 3772 CPC Packing List

Krytox® is a registered trademark of DuPont.

2-1

Table 2-2

Qty.

Description

Model/ Part Number

Model 3771 CPC and Operation Manual

1980529

Power cable

(based on destination)

Aerosol Instrument Manager® Software

390065

Fill Bottle

1035590

Drain Bottle

1035591

Bottle Bracket

1503475

Vacuum Drain Bottle Cap

1031526

RS-232 Cable (A-pin M/F, 12 ft)

962002

USB I/O Cable A/B 6 ft

1303740

Saturator Wick CPC 3771

1600047

Water Removal Filter Inline, 25 micron 116" barb

1500192

Butanol Fill/Drain Filter Inline, 73 micron 18" barb

1602088

Saturator Base O-Ring FVMQ 1-010

2500021

Saturator Base O-Ring FVMQ 1-030

2501172

Saturator Base O-Ring EPDM 1-027

2501569

Krytox® O-ring Grease

1701154

Checkout Data Sheet

N/A 1 Certificate of Conformance

N/A

Model 3771 CPC Packing List

Unpacking

Note: Some items in the lists above and those for future maintenance are

available for purchase as kits from TSI. A complete list of replacement part kits is included in the maintenance section in

Chapter 8.

The Model 3772/3771 CPC comes fully assembled with protective coverings on the inlet sample port, exit ports, and analog connectors. The CPC comes packaged with the accessory kit. Use the packing list (Table 2-1 or Table 2-2) to make certain that there are no missing components.

The CPC box contains special foam cutouts designed to protect the instrument during shipment. Save the original packaging materials for future use should you need to ship the instrument or return the instrument to TSI for service. Also keep the protective coverings for ports for shipping.

To avoid contaminating the instrument or the environment the CPC is monitoring, do not remove the protective covers until you are ready to install the instrument.

If anything is missing or appears to be damaged, contact your TSI representative or contact TSI Customer Service at 1-800-874-2811 (USA) or (651) 490-2811. Chapter 8, “Maintenance and Service,” gives instructions for returning the CPC to TSI Incorporated.

2-2 Model 3772/3771 Condensation Particle Counter

Setting Up

This section contains instructions for setting up the Model 3772/3771 CPC. Follow the instructions in the order given.

Remove Protective Caps

Remove all protective caps from the inlet sample port and exit flow ports at the back of the instrument, also remove covers from the BNC connectors.

Mounting the Bracket and Fill Bottle

Mount the black anodized aluminum Bottle Bracket to the back panel using two 8-32  38-inch screws and two no. 8 lock-washers found in the mounting hole locations. Refer to the location of the bottle bracket shown in Figure 2-1.

Find the Fill Bottle in the accessory kit. Connect the bottle tube fitting to the Butanol Fill port at the back panel of the instrument. Position the bottle with the fitting oriented for minimal stress on the tubing connector on the back panel and place the bottle in the bracket. Both mated fittings are leak-tight when disconnected.

Figure 2-1

View of Fill Bottle Bracket Mounting

Unpacking and Setting Up the CPC 2-3

Filling the Fill Bottle with Butanol

C a u t i o n

Butanol is flammable. Butanol is also potentially toxic if inhaled. Use

butanol only in a well-ventilated area. If you smell butanol and develop a headache, or feel faint or nauseous, leave the area at once. Ventilate the area before returning.

The Model 3772/3771 CPC uses reagent-grade n-butyl alcohol (butanol) as the working fluid for particle growth. Pour the butanol into the Fill Bottle to at least one-third full. Because of the leak-tight fittings and internal solenoid valve, liquid will not flow into the CPC until the connections are made, the instrument is switched on, and warm-up cycle is complete.

Note: Due to shipping regulations on flammable materials, n-butyl alcohol

(butanol) is not supplied with the CPC. Butanol may be purchased from scientific chemical supply houses. Reagent grade of butanol is required.

Connecting the Butanol Drain Bottle

A drain bottle should be connected to the Liquid Drain port at the back panel of the CPC. The drain bottle collects butanol drained from the CPC prior to transport and holds condensed water and butanol removed from the condenser when the water removal system is turned on (see note below). Draining butanol is described in Chapter 8 “Maintenance and

Service”.

Note: The water removal system will not work without a drain bottle

connected to the drain port. Refer to Chapter 4 for more details on water removal system.

Apply Power to the CPC

Plug the power cord into the receptacle on the back panel of the CPC and then plug it into the AC power source. The instrument uses a universal power supply that accepts a variety of input voltages identified below.

Power 100 – 240 VAC, 50/60 Hz, 200 W maximum

Note: Make certain the power cord is plugged into a grounded power

outlet. Position the CPC so the power connector and switch are easily accessible in case an emergency disconnect is required.

Apply power to the CPC by turning on the switch next to the power cord on the back panel.

The instrument begins a warm-up sequence which typically lasts ten minutes at room temperature. On the 3772, a ten-minute countdown is displayed on the front panel. Particle concentration will not be accurately measured during warm-up. After warm-up completes, the fluid begins to fill the internal butanol reservoir in the saturator.

2-4 Model 3772/3771 Condensation Particle Counter

Supply External Vacuum to the CPC

An external vacuum port is located in the lower right-hand corner of the CPC back panel. An external vacuum must be connected to this port before the CPC can count particles. Vacuum source, either a central building vacuum or a stand-alone vacuum source (e.g., TSI Model 3032 Vacuum Pump), should provide at least 60 kPa (18 in. Hg) vacuum and

1.0 L/min critical flow at the inlet of each CPC. Details of vacuum specifications are given in Chapter 5.

Positioning the CPC

Place the CPC on a level surface. Ensure the cooling fan on the back panel of the CPC is exposed to ambient air.

Note: If the CPC has n-butyl alcohol (butanol) in the reservoir, be very

careful when moving the CPC. See “Moving and Shipping the CPC” section for details.

Unpacking and Setting Up the CPC 2-5

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2-6 Model 3772/3771 Condensation Particle Counter

C H A P T E R 3

Instrument Description

Use the information in this chapter to become familiar with the location and function of controls, indicators, and connectors on the Model 3772 and 3771 Condensation Particle Counters (CPC).

Model 3772 Front Panel

The main components of the 3772 front panel include the two-line LCD display, six-key push button keypad, flash memory card slot, aerosol inlet, two LED indicator lights (particle and status). These are identified in Figure 3-1 and described below.

LCD Display and Keypad

The two-line backlit LCD provides continuous real-time display of sample data and is used in conjunction with the keypad to display option menus, instrument status information, and user settings. Refer to Chapter 4 for details on how to make selections and change options on the menus.

Figure 3-1

View of the Model 3772 Front Panel

3-1

Aerosol Inlet

The aerosol inlet is located on the front panel. The inlet consists of a ¼” OD tube suitable for use with common tube fittings. Permanent fittings with metal locking ferrules should be avoided since this can deform the tube when overtightened, leading to leaks.

Status Light

The status light indicates the working status of the CPC. It will light only when the key performance parameters of the CPC fall within an acceptable range. More information on the status light is provided in Chapter 4.

Particle Light

The particle light flashes each time a particle is detected. At high particle counting levels (>10 counts per second) the light appears continuously on.

Flash Memory Card Slot

The Model 3772 CPC provides storage of particle concentration data using a standard flash memory card. A flash memory card is included. Refer to

Using the Flash Memory Card in Chapter 4 for more on how to use the

Flash Memory Card. Technical information is also found in Chapter 7.

3-2 Model 3772/3771 Condensation Particle Counter

Model 3771 Front Pane l

The main components of the 3771 front panel include the aerosol inlet and two LED indicator lights (particle and status). These are identified in Figure 3-2 and operate the same as described above for the 3772.

Figure 3-2 View of the Model 3771 Front Panel

Model 3772/3771 Back Panel

As shown in Figure 3-3, the back panel of the 3772/3771 CPC has power and data connections, analog input/output connections, external vacuum port, butanol fill and drain ports, and cooling fan. The function of the ports and connectors are clearly labeled.

AC Connector and Switch

Plug the supplied AC power cable into this receptacle. The instrument power switch is integrated into this AC receptacle at the top.

USB Communication Port

The Model 3772/3771 CPC provides a USB port for use with the TSI Aerosol Instrument Manager® software included with the instrument. When USB communications are used with the software, the computer automatically recognizes the CPC as a TSI instrument. Additional information on USB communications is found in Chapter 7 and also in the Aerosol Instrument Manager® software manual.

Instrument Description 3-3

Note: Up to three CPCs can be simultaneously connected to one

computer running Aerosol Instrument Manager® software with USB connections.

Figure 3-3 Back Panel of the Model 3772/3771 CPC

RS-232 Serial Connections

The Model 3772/3771 CPC provides two standard A-pin RS-232 serial ports that allow communication between a computer and the CPC. Serial commands are sent to and from the computer to monitor instrument status information, to retrieve and monitor data, and to provide a variety of control functions such as turning the water removal system on and off (Serial 1 only). Aerosol Instrument Manager® software may be used with Serial 1 as well as USB. Information on RS-232 communications can be found in Chapter 7, “Computer Interfaces and Commands”.

3-4 Model 3772/3771 Condensation Particle Counter

Analog Inputs

The CPC can monitor the analog voltages from two external sources via the analog input BNC connectors on the back panel, labeled Analog Input 1 and Analog Input 2. The input voltage range for these ports is 0 to 10 volts. On the 3772 the analog voltages can be displayed on the LCD display and saved to the removable Flash Memory Card or a computer. Voltages from external pressure, flow, or temperature transducers can be correlated to particle concentration in real time.

Amplification must be supplied by the user to bring low voltage signals to the appropriate 0 to 10 volt range for best resolution.

DMA/Analog Output and Pulse Output

The DMA/Analog Output port provides an analog 0–10 V signal linearly proportional to particle concentration. This particle concentration is corrected for coincidence and equals the concentration displayed on the front panel of the CPC and the concentration saved to the Flash Memory Card or computer. Refer to Chapter 4 for details. In addition, on the 3772 this port can be configured by the Aerosol Instrument Manager® software to provide the ramped voltage signal needed when the 3772 CPC is used as part of the Scanning Mobility Particle SizerTM (SMPSTM) spectrometer. Although this port on the 3771 is also labeled DMA/Analog Output, the DMA function is not available for the 3771.

Pulse Output port provides a 5-volt (50-ohm termination) digital pulse for each particle detected. This enables you to use your own counting electronics hardware or provides a particle trigger for special applications. The width of the pulse depends on both the shape of the photodetector pulse and the trigger-level of the pulse threshold. Typical (nominal) pulse widths are 350 nanoseconds (see Figure 3-4) for the 3772/3771 CPC. To provide accurate pulse counts, use a counter that is capable of counting pulses with a width of 50 nanoseconds or less.

Particle concentrations calculated based on the particle counts from the counting electronics hardware are not corrected for particle coincidence. Thus, the concentration obtained this way might be slightly lower than the displayed concentration when particle concentration is high. Refer to Chapter 6 “Particle Counting” for coincidence correction for pulse output.

The Pulse Output is a way to get raw particle count information. This information is also available through serial command. Using the SSTART,2 command, described in Appendix B, you can read raw, uncorrected, particle counts. TSI recommends using the SSTART,2 command for raw counts as then all the information is shipped which is used to calculate the corrected concentration, and there are no issues with the counters ability to accurately count the pulses.

Instrument Description 3-5

Figure 3-4 Sample Digital Pulse from Pulse Output Port at the Back Panel of the CPC

Ethernet Communication Port

Instrument status including particle concentration of the Model 3772/3771 CPC can be monitored remotely from a local area network or over the internet using the Ethernet communication port. Ethernet communications are described further in Chapter 7, “Computer Interfaces and Commands”.

Butanol Fill Port

Butanol is supplied from the butanol fill bottle to the instrument at the Butanol Fill port quick connect fitting.

External Vacuum Port

By attaching an external vacuum to this port, critical flow is established through the critical orifice described in Chapter 5. The flow through this port contains butanol vapor so the external vacuum must be properly vented away from work areas or use charcoal filter to absorb the butanol vapor. Charcoal filters can be ordered through TSI (P/N 1031492 and P/N

1031493). See Chapter 8 “Maintenance and Service.”

3-6 Model 3772/3771 Condensation Particle Counter

Cover

The bottom portion of the chassis provides access to the saturator wick. As shown in Figure 3-5, the saturator base, which is attached to the wick, is visible above the centrally located 2.5-inch diameter hole on the bottom panel. The base and wick can be removed for maintenance, as described in

Chapter 8.

Figure 3-5

Bottom Panel Showing Removable Saturator Base

Drain Port

This port is used to drain the working fluid (butanol) from the 5 cm3 liquid reservoir and is used when collecting water extracted using the Water Removal system. See Chapters 3 and 4 for more on the water removal feature.

Instrument Cooling Fan

This fan cools internal electronics and dissipates heat generated during cooling of the condenser. The fan is provided with a guard and a removable filter that should be cleaned of dust periodically.

The cover refers to the removable section of the chassis covering the top and sides of the CPC. It is secured to the chassis with four screws on the bottom and two on the top and it can be removed for access to the interior of the Model 3772/3771 CPC. Refer to Chapter 8 for details.

Bottom Panel

Instrument Description 3-7

Internal Instrument C o m ponents

1. Sensor assembly

5. Critical orifice

2. Water removal pump

6. Pressure transducers

3. Butanol fill filter

7. Power supply

4. Fan

Internal components are described in this section and identified in Figure 3-6 and Figure 3-7.

Figure 3-6

Internal Components of the Model 3772/3771 CPC

Water Removal Pump

The Model 3772/3771 CPC uses a micro-flow Water Removal Pump to remove condensate from the condenser. The Water Removal Pump draws condensed butanol and water from the condensate collection reservoir. Water removal prevents contamination of the butanol during operation in a high humidity environment. When activated, the pump runs continuously. A drain bottle must be connected for water removal to occur. For information on operating the water removal pump refer to Chapter 4, “User Settings.”

3-8 Model 3772/3771 Condensation Particle Counter

Filters

The CPCs use three liquid filters. One liquid filter is used to filter butanol supplied from the fill bottle while a second filters the butanol drain line. The third is used to filter the condensed water and butanol mixture before it passes through the Water Removal Pump.

Valves

Solenoid fill and drain valves enable butanol to be added or removed from the liquid reservoir. The fill valve is actuated when the Auto-Fill is turned ON and the level sensor indicates a low butanol level in the liquid reservoir. When the butanol fill bottle is connected, butanol flows into the reservoir until the level sensor indicates a full state. On the 3772, the drain valve is activated through the front panel or through serial command. On the 3771, the drain valve is activated through serial command. Butanol is drained

prior to shipment or removal of the saturator wick. See “User Settings” in Chapter 4 and “Maintenance and Service” in Chapter 8.

Pressure Transducers

The Model 3772/3771 CPC uses three pressure transducers for monitoring instrument flows. The differential pressure across the Critical Orifice is measured to verify that a critical pressure is maintained across the orifice. Differential pressure across the nozzle is measured and verifies the nozzle in the optics block is free from obstruction. The ambient pressure is also measured. These pressure transducers are mounted to the main PC board. On the 3772, pressure information is viewable via the front panel display. On both 3772 and 3771 CPCs, pressure information is available through serial commands.

Electronics Boards

Four electronics boards identified in Figure 3-7, are used in Model 3772/3771 CPC. The boards include main PC board, laser board, detector board, and communication connector board. The 3772 also includes a fifth board—flash memory board.

Instrument Description 3-9

Figure 3-7

1. Main PC board

4. Communication connector board

2. Laser board

5. Flash memory board (3772 only)

3. Detector board

Electronics Boards inside the Model 3772/3771 CPC

Basic Instrument Fu n c tions

This section describes basic instrument functions.

Concentration Measurement

Particle concentration is presented as particles per cubic centimeter (p/cc). For the 3772, the particle concentration is displayed on the front panel LCD in numeric form. For both CPCs, data is collected using the Aerosol Instrument Manager® software or other terminal program (such as HyperTerminal). Particle concentration is determined from the count rate (particles counted per tenth of a second) and the aerosol flow rate, nominally 1000 cubic centimeters per minute (cm3/min). The concentration is also live-time corrected for coincidence. Refer to Chapter 6 “Live-Time

Counting” for more information.

3-10 Model 3772/3771 Condensation Particle Counter

Total Count Mode (3772 only)

Total Count Mode (also called totalizer mode) counts number of particles in a given time period. This mode is used to improve counting resolution at very low particle concentrations. Time and number of counts are shown on the front panel display of the 3772.

Water Removal

When the aerosol sample has a dew point above the condenser temperature of 22°C, water vapor may condense on the walls of the condenser and run back into the saturator, contaminating the butanol over time. Unlike its predecessor, the Model 3010, 3760A, or 3762 CPC, the Model 3772/3771 CPC is able to capture condensed water vapor and remove it, significantly reducing butanol contamination in high humidity environment. The water removal process increases the butanol consumption. For additional information refer to Chapter 4.

Internal Data Logging (3772 only)

A removable Flash Memory Card can be inserted in the slot on the 3772 front panel to store data including particle concentration and analog input data. Data can then be transferred to a computer for further data processing. Refer to Chapter 4 for more details. It is not recommended you use a Flash Memory Card and Aerosol Instrument Manager® software or terminal program to collect data simultaneously to avoid data transfer interference.

Remote Access of Instrument

The Model 3772/3771 CPC provides an Ethernet port to connect the instrument to a network for monitoring status information. Status information includes saturator, condenser, optics temperatures, laser power, and particle concentration, etc. The data is updated once every five seconds. Refer to Chapter 7 for more details.

External Vacuum Pump or Source

The external vacuum pump or source must provide sufficient vacuum to maintain a critical pressure across the critical orifice, while providing an aerosol flow of 1.0 L/min. At an atmospheric pressure of 100 kPa (1 atm), an external pump or other vacuum source must provide at least 60 kPa (18 in. Hg) of vacuum and 1.0 L/min inlet volumetric flow for each CPC supported. TSI offers Model 3032 Vacuum Pump for one CPC and Model 3033 Vacuum Pump for multiple CPCs. Contact TSI technical support for more information on use of an external vacuum pump.

Instrument Description 3-11

Flow Rate Control

The Model 3772/3771 CPC uses a critical orifice to accurately control the air flow in the instrument. The critical orifice operates at or below a critical pressure to control the 1.0 L/min volumetric aerosol flow. More is found in Chapter 5 “Technical Description.”

Problems with the aerosol flow can be detected by monitoring the pressure drop across the nozzle, and verifying that the critical orifice pressure is maintained.

Temperature Control

The temperatures of the condenser, saturator, and optics are maintained at 22 °C, 39 °C, and 40 °C, respectively, with specified ambient temperatures in the operating range of 10 to 35 °C. The temperatures are controlled through feedback circuits on the main electronics board and are viewable via firmware commands. For the 3772, the temperatures are also viewable with the Status display screen. If the temperatures are out of range on either CPC, the status indicator LED on the front panel will be off. For ambient temperatures outside the instrument operating range, the instrument temperature performance may not be maintained. Moderate increases in saturator temperature and optics are tolerated in some instances, depending on measurement requirements.

Inlet Pressure Measurement

With adequate external vacuum, the instrument is capable of operating at inlet pressures in the range of 75 to 105 kPa. The inlet pressure is measured by an absolute pressure sensor, and is essentially the barometric pressure if no inlet restriction is present. Inlet Pressure is accessible through firmware commands on both 3772 and 3771 CPCs and it is also viewable via the Status display screen for the 3772. Refer to

Chapter 4 for more details.

3-12 Model 3772/3771 Condensation Particle Counter

W A R N I N G

Although the Condensation Particle Counter is appropriate for monitoring

inert process gases such as nitrogen or argon, it should not be used with hazardous gases such as hydrogen or oxygen. Using the CPC with hazardous gases may cause injury to personnel and damage to equipment.

C H A P T E R 4

Instrument Operation

This chapter describes the basic operation of the Model 3772/3771 Condensation Particle Counter (CPC) and provides information on the use of controls, indicators, and connectors found on the front and back panels.

Operating Precautions

Read the following before applying power to the 3772/3771 CPC:

 Review the operating specifications for the CPC in Appendix A.  Do not operate the CPC outside the range of 10 to 35 C. If the CPC is

operated outside this range, the displayed concentration may be inaccurate.

Power Switch

Warm-up

 If the CPC reservoir contains butanol, be very careful when moving the

CPC. Refer to “Moving and Shipping the CPC” for more details.

The power switch is found on the back panel of the CPC. The switch is combined with the power cord receptacle.

When the CPC is turned on, the saturator, condenser, and optics have to reach set operating temperatures. This “warm-up interval” takes about 10 minutes at room temperature. The Status LED indicator on the front panel will remain unlit during this time. Under extremes in ambient temperature, it may take considerably longer for the instrument to warm-up.

On the 3772 front panel display, a countdown is also displayed during the warm-up time, as shown in Figure 4-1.

4-1

Figure 4-1

Model 3772 Display During Warm-Up

When warm-up is complete, the concentration is automatically displayed for the 3772 as shown in Figure 4-2. The concentration can also be displayed before the warm-up is complete by pressing the ESC key at any time.

Figure 4-2

Model 3772 Display After Warm-Up is Completed

Status Indicator

A status LED indicator on the front panel of the Model 3772/3771 CPC indicates the overall status of the CPC. It will remain unlit if a key parameter falls outside of the acceptable operating range. Parameters monitored include instrument temperatures, pressures, and liquid level. Generally it will light after warm-up time is complete, an external vacuum is applied, and butanol has filled the reservoir. See Chapter 8 for troubleshooting instructions if the Status indicator LED does not turn on.

Particle Indicator

A particle LED indicator light on the front panel of the CPCs indicates particle counts.

Communication

CPC measurement data, instrument status, and user settings are available through firmware communication for both Models 3771 and 3772 and also viewable through the front panel for Model 3772. For more information on firmware communication, see Chapter 7 and Appendix B.

4-2 Model 3772/3771 Condensation Particle Counter

Model 3772 LCD Display and Keypad

In addition to firmware communication, Model 3772 presents measurement data, instrument status, and user settings on a 2-line, 16-character, alphanumeric LCD display. You can navigate the menu options using the six-button keypad. The display and keypad are shown in Figure 4-3.

Figure 4-3 Model 3772 Front Panel LCD Display and Keypad

Model 3772 Keypad Navigation

As shown in Figure 4-3, the keypad has six keys: scroll left , scroll right

, scroll up , scroll down , Enter , and ESC . Detailed

navigation instructions are described below. Generally,

 The up and down arrows are used to scroll through a given menu.  The left and right arrows are used to configure user settings. The new

setting becomes active immediately after the setting is selected.

 The Enter  The ESC

key displays submenus.

key returns the display out of a submenu.

The control menu has a two-tier hierarchy. There are four primary functions: Concentration, User Settings, Status, and Total Count Mode. By pressing the up or down arrow, the display will scroll through these four functions.

Two of the primary functions, User Settings and Status, have submenus. A submenu can be accessed by pressing the Enter key. Once inside a submenu, the up or down arrow can be used to scroll through the

features. The submenu for User Settings contains all the options for configuring the CPC. The submenu for Status contains all the parameters for monitoring the CPC. The primary functions are summarized below along with their submenus. These are described in detail in the following sections.

Instrument Operation 4-3

Primary Function

Secondary Submenu

Concentration

Aerosol concentration measured in [p/cc]

No submenu available.

User Settings

Displays features available for configuration

Data Logging, Water Removal, Totalizer Time, Auto Fill, Analog Out, Data Averaging, and Drain.

Status

Displays operating parameters and status of CPC

Saturator Temperature, Condenser Temperature, Optics Temperature, Cabinet Temperature, Ambient Pressure, Orifice Pressure, Nozzle Pressure, Laser Current, Liquid Level, Analog Input 1, Analog Input 2, Flash Status, USB status, Firmware Version

Total Count Mode

Accumulates particle counts and clock time

No submenu available.

Concentration

The CPC measures aerosol concentration in particles per cubic centimeter. The 3772 displays a Concentration screen as shown in Figure 4-3. This is the default display. Pressing ESC twice from any other screen returns the display to Concentration screen. The LCD is updated once per second. For both 3771 and 3772, concentration data can be accessed through firmware communication using “RD” command. Refer to Chapter 7 and

Appendix B for more information on firmware commands. The maximum

concentration limit for the 3772/3771 is 10,000 particles/cm3. When concentration exceeds 10,000 particles/cm3 for a 3772, two

exclamation marks appear on the LCD main display, one in front of the concentration value and one after. For both 3772 and 3771 CPCs, measurements with concentrations that exceed 10,000 are flagged and the status LED will be turned off.

4-4 Model 3772/3771 Condensation Particle Counter

Total Count Mode (3772 only)

Total Count Mode allows particle counts to be accumulated and displayed as shown in Figure 4-4. Total Count Mode is generally useful for tests at very low particle concentrations (e.g., below 10.0 particles/cm3), such as evaluation of high efficiency filters.

To access Total Count Mode from the default Concentration screen, press the down arrow once. When first accessed, the display appears as shown in Figure 4-5. By pressing Enter , the screen changes to Figure 4-5. Pressing Enter again at this screen will cycle between

Start, Stop, and Reset. The CPC will count time and total particles once Start is set. The sample automatically stops when the time is equal to the Totalizer Time. Totalizer Time can be set in the User Setting submenu.

Figure 4-4

Total Count Mode Data Screen

Figure 4-5 Initial Total Count Mode Data Screen

User Settings

User settings can be configured through firmware commands on both 3772 and 3771. Refer to Chapter 7 and Appendix B for information on firmware commands. On the 3772, User Settings is also accessible from the front panel display. It is a primary function accessible from the default Concentration screen by pressing the up arrow once. The screen appears as in Figure 4-6. Pressing Enter once brings up the submenu. Once inside the submenu, the up or down arrow can be used to scroll through a list of configurable settings. To change a setting, use the left or right arrow. The setting takes effect immediately after it is selected. Pressing ESC once returns the display to User Settings as shown in Figure 4-6. User settings in the menu are described under individual headings below, beginning with the Data Logging.

Figure 4-6

User Settings Display

Instrument Operation 4-5

Data Logging (3772 only)

Imp ort a nt Note

The Drain Bottle must be connected for the water removal system to work properly.

Butanol Consumption

The water removal feature removes condensed butanol as well as water, increasing butanol consumption. The operator may elect not to use water removal in cool/dry environments to preserve butanol. When water removal is not used, butanol is recycled. A full bottle of butanol (1 liter) lasts approximately 7 days with the water removal system ON and last 15 days with the water removal system OFF.

Data can be saved on a Flash memory card on the 3772. By default Data Logging is “OFF.” To initiate data logging, switch the Data Logging user setting to “ON” by pressing the left or right arrow once. Logging will begin immediately. Press the arrow again to toggle Data Logging to “OFF” to stop. More information on data logging is provided under “Using

the Flash Memory Card.” Use the Data Averaging option in User Settings

to set the data averaging interval for data collection.

Water Removal

The Water Removal option provides ON/OFF control for the water removal feature of the CPC. The default setting is “OFF.” On the 3772 it can be set from the Water Removal option in the submenu of User Settings. Pressing the left either 3772 or 3771 CPC, it can be turned on using the “SAWR” firmware command. See Chapter 7 and Appendix B for information on firmware commands.

Water Removal system is used in hot/humid environments to eliminate contamination of the butanol working fluid by condensed water vapor. Water removal keeps the CPC operating at peak performance.

or right arrow toggles Water Removal system on or off. On

Water removal is achieved by collecting all condensate from the cooled condenser before it has a chance to return and remix with the butanol in the heated saturator. The collected condensate is pumped to the Drain port and flows into the supplied Drain Bottle.

4-6 Model 3772/3771 Condensation Particle Counter

Totalizer Time (3772 only)

Option

Concentration Range for Analog Output 0–10 V

Relation

OFF

0 V independent of concentration

1E+1

0 to 10 particles/cm3

linear

1E+2

0 to 100 particles/cm3

linear

1E+3

0 to 1,000 particles/cm3

linear

1E+4

0 to 10,000 particles/cm3

linear

OFF

0 V independent of concentration

The Totalizer Time feature is available from the User Settings submenu. Use this feature with the Total Count Mode function to select the time period for accumulating counts. Three options are available: 1 minute, 60 minutes, and Continuous. The default setting is “Continuous.” Pressing the left

or right arrow will cycle through these three options. Time and count accumulation stops once the time is complete. The accumulation can also be ended manually prior to the end of a sampling period from the Total Count Mode display.

Auto Fill

When the Auto-Fill option is ON, the instrument fills with butanol automatically when the liquid level indicator in the butanol reservoir detects a low butanol level condition. Selecting Auto-Fill OFF prevents the fill valve from opening despite a low butanol level. Note that a Drain command will turn Auto-Fill to OFF. Auto-Fill can be turned back on by using the AutoFill setting or by restarting the CPC.

On the 3772, an Auto Fill option is available in the User Setting submenu. Pressing the left

both 3771 and 3772, Auto-Fill can be set ON or OFF with the “SFILL” firmware command. See Chapter 7 and Appendix B for more information on firmware commands.

or right arrow will toggle Auto-Fill ON or OFF. On

Analog Out

The Analog Out setting configures the signal from the “DMA/Analog

Output” port on the back panel. This analog signal is from 0 to 10 V. There are five options available to select: OFF, 1E+1, 1E+2, 1E+3, 1E+4. The analog signal is linearly proportional to particle concentration when it is turned on. The relationship between voltage output and particle concentration is listed below.

On the 3772, the Analog Out option is available in the User Settings submenu. Pressing the left

options. The scaling and OFF options are available to the 3771 and 3772

through the “SAO” firmware command. See Chapter 7 and Appendix B for

more information on firmware commands.

or right arrow will cycle through the

Instrument Operation 4-7

Data Averaging (3772 only)

When Data Logging is set to “ON”, data is averaged over selected Data Averaging Period for saving to the flash memory card. The Data Average Periods available are 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, or 60 seconds. By default the Data Average Period is 1 second.

To change the Data Average Period, the Data Logging option first must be set to “OFF.” Then in the Data Average Period display, press the right or left arrow to cycle through the available Data Average Periods. When the desired period is displayed, press ESC to return to the User

Settings screen. The Aerosol Instrument Manager® software provides more choices for data

average period. See the software manual for details. It is not recommended you use a Flash Memory Card and Aerosol Instrument Manager® software or terminal program to collect data simultaneously to avoid data transfer interference.

Drain

The Drain feature is used as part of the process to drain butanol from the reservoir. It opens the drain valve and turns Auto-Fill mode OFF. When the drain is complete, Auto-Fill must be turned back on by using Auto-Fill setting or by restarting the CPC. For specific instructions on draining

butanol, refer to the section “Draining Butanol from the Butanol Reservoir”

in Chapter 8. On the 3772 the Drain feature is available from the User Settings

submenu. Pressing the left OFF. On the 3771 the Drain feature is controlled through the “SDRAIN” firmware command. Refer to Chapter 7 and Appendix B for further information on firmware commands.

or right arrow toggles Drain ON or

Status

Status information provides data from instrument sensors useful to confirm basic performance and for troubleshooting. The Status parameters are described below, beginning with Saturator Temperature.

Status parameters are accessible through firmware commands for both CPCs. Refer to Chapter 7 and Appendix B for further information on firmware commands.

On the 3772, the parameters are also available from the Status menu. To access the Status menu on 3772, start at the default Concentration screen and press the up Figure 4-7. Press the Enter Toggle through submenus (status parameters) with the up

arrow. Pressing ESC once returns the display to the Status

4-8 Model 3772/3771 Condensation Particle Counter

arrow twice. The Status screen appears as shown in

key to view the submenus for Status.

or down

screen as shown in Figure 4-7. If any of the status parameters deviates from the normal condition, the status light is off and there are two exclamation marks around the parameter: one before and one after, as shown in Figure 4-8.

Figure 4-7 Status Display

Figure 4-8 Status Parameter Display for Diagnostics

Saturator Temp (Temperature)

Saturator temperature is 39.0 °C when the instrument warm up is complete and the instrument has stabilized. The saturator provides saturated butanol vapor that mixes with aerosol particles in the condenser.

Condenser Temp (Temperature)

Particle growth occurs in the condenser as butanol vapor from the saturator is cooled, supersaturated, and condenses on sampled aerosol particles. The condenser temperature is maintained at 22.0 °C.

Optics Temp (Temperature)

The optics temperature is maintained at 40.0 C. This is above the saturation temperature and prevents butanol from condensing on the lenses and other internal components in the particle detection optics.

Cabinet Temp (Temperature)

The cabinet temperature measures the temperature inside the CPC.

Ambient Pressure

Ambient pressure is the barometric air pressure in kPa. Inlet air pressure is very close to the barometric pressure when sampling directly from the ambient environment. A restriction at the inlet will change the inlet air pressure. The instrument is designed to operate with an inlet pressure between 75 and 105 kPa.

Instrument Operation 4-9

Orifice Pressure

Orifice pressure is the differential pressure across the aerosol flow critical orifice in kPa. Identification of the orifice is found in the flow schematic Figure 5-1.

Nozzle Pressure

Nozzle pressure is the differential pressure across the nozzle between the condenser and the optics chamber in kPa. Identification of the nozzle is found in the flow schematic Figure 5-1.

Laser Current

Laser power is monitored by an internal detector in the diode laser package. If laser light energy drops and the laser current is below 35 mA, an Error is indicated and the Status light is OFF.

Liquid Level

FULL is indicated if adequate butanol is present in the liquid reservoir. Liquid level is detected by a heated RTD (Resistance Temperature Detector) level detector. If the liquid level is low, NOT FULL is indicated.

Analog Inputs

Analog Input 1 and 2 display voltages supplied to the BNC connectors at the back panel of the instrument. These analog data inputs have a range of

0 to 10 volts. Voltages can come from a variety of sources at the operator’s

discretion. Signals should be gained up or down so the outputs fall into the 0-to-B-volt window with maximum resolution. On both 3772 and 3771 CPCs, analog input data is saved along with concentration data through firmware commands or to a computer running Aerosol Instrument Manager® software. On the 3772 analog input data can also be saved to the Flash Memory Card when a card is present and data logging is ON.

Flash Status (3772 only)

When a flash memory card is present, READY is indicated. When a flash memory card is present and data logging is ON, LOGGING is indicated. When there is not a flash memory card, REMOVED is indicated. See more details below.

USB Status

When the USB port on the back panel of the 3772/3771 CPC is connected, the status indicates CONNECTED. The status indicates DISCONNECTED when there is no connection to the USB port.

4-10 Model 3772/3771 Condensation Particle Counter

Firmware Version

This option shows the current firmware version of the instrument.

Using the Flash Memor y Card (3772 only)

Particle concentration data and analog input data can be saved to a Flash Memory Card inserted in the slot at the middle right of the front panel. Insert the card with the label facing right.

Data logging is initiated (turned ON) from the front panel under the User Settings Menu. A file having a .DAT extension is created and will sample one hour of CPC data. Additional files will be created automatically each hour, i.e., having one hour of data. A shorter file is created if the test is stopped by turning Data Logging OFF. Data is lost if an open file is improperly closed, by turning the instrument off or removing the flash memory card.

To read saved data to computer, connect the supplied card reader to your computer using the USB cable. Insert the flash card in the reader. Your computer will recognize the card reader and display a window showing several options. Select the option Open folder to view files to access the test files on the installed memory card. The file names are based on the date and time when the test was initiated.

The Aerosol Instrument Manager® software described below retrieves files from the flash memory card for data display. Refer to your Aerosol Instrument Manager® software instruction manual for information on importing .DAT data files.

Additional technical information on the flash memory card is found in

Chapter 7.

Notes: Data cannot be saved to the flash memory card and to the

computer through Aerosol Instrument Manager® software simultaneously.

Keep the amount of data stored in the flash memory card under

64 MB to avoid long overhead time before generating a new data file each hour in the card.

Flash Memory Card Format

The data card supplied with Model 3772 CPC is formatted as per FAT32 file system. This ensures data is logged and saved properly. Should you use another external data card, make sure that you reformat the card to the FAT32 file system before logging data.

Note: Recording data on memory cards not formatted to FAT32 file

system can result in malfunctioning of the data logging system. This may cause the CPC to freeze at the end of a run and loss of previously recorded data files.

Instrument Operation 4-11

Follow the steps below to reformat your card:

1. Connect the supplied card reader to your computer using the USB cable.

2. Insert the flash card in the reader. The flash memory card will appear as a separate disk drive in Microsoft® Internet Explorer® browser.

3. If you have any data on the flash memory card you want to save, you must copy it to a temporary directory on your computer, because the reformat will erase it from the flash card.

4. Put your cursor on the flash memory card’s drive letter in Microsoft® Internet Explorer® browser and right click. Select Format.

5. Under File System, make sure “FAT32” is selected. Click on Start.

6. When it is done reformatting, copy any files you saved back onto the flash memory card.

7. You can check the format type of the flash memory card at any time by right clicking on the drive letter in Microsoft® Internet Explorer® browser. Select Format and look under File System.

Figure 4-9

Reformatting the Flash Memory Card

4-12 Model 3772/3771 Condensation Particle Counter

C a u t i o n

Remove the flash memory card following the correct procedures:

1. Use Safely Remove Hardware option in Windows to disconnect the card reader from the computer—stop USB Mass Storage Device.

2. After the message Safe To Remove Hardware: The “USB Mass Storage Device” device can now be safely removed from the system appears, physically remove the flash memory card from the card reader.

Failure to follow these procedures may result in failure to log data with the flash memory card.

Aerosol Instrument Mana g e r® Software

C a u t i o n

With the vacuum on and butanol in the reservoir, do not tip the counter

more than 10° in any direction. It is recommended to turn off the CPC and disconnect the butanol fill bottle before the CPC is being moved or tilted for longer than a few seconds to prevent flooding the sensor.

Aerosol Instrument Manager® software is supplied with the 3772/3771 CPCs. This program provides many useful data acquisition, display, processing, and download functions used in particle measurements. Review the supplied Aerosol Instrument Manager® software manual for complete information on software functions.

Moving and Shippi n g the CPC

Make sure the Model 3772/3771 CPC is turned off and remains upright while moving the instrument. There is no need to drain the CPC before moving it. Prior to shipping, however, it is necessary to drain butanol from the instrument. Refer to “Draining Butanol from the Butanol Reservoir” in Chapter 8 to drain the CPC.

TSI recommends that you keep the original packaging (carton and foam inserts) of the CPC for use whenever the CPC is shipped, including when it is returned to TSI for service. Always seal off the sampling inlet to prevent debris from entering the instrument and drain and dry the CPC before shipping.

Instrument Operation 4-13

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4-14 Model 3772/3771 Condensation Particle Counter

Theory

C H A P T E R 5

Technical Description

The Model 3772/3771 CPC is a continuous-flow condensation particle counter that detects particles as small as 10 nanometers (50% detection efficiency) in diameter. This section describes the function of the CPC, its subsystems and its components. A discussion of operation theory and history is given first.

The CPC acts very much like an optical particle counter. However, the particles are first enlarged by a condensing vapor to form easily detectable droplets. The science behind the counter, therefore, is focused on how to condense the vapor onto the particles. Portions of the following discussion are taken from a paper by Keady et al. [1986].

When the vapor surrounding particles reaches a certain degree of supersaturation, the vapor begins to condense onto the particles. This is called heterogeneous condensation. If supersaturation is too high, condensation can take place even if no particles are present. This is referred to as homogeneous nucleation or self-nucleation, whereby molecules of the vapor form clusters due to the natural motion of the gas and attractive van der Waals forces to form nucleation sites. This condition is avoided by accurately controlling operating temperatures. The CPC operates below the supersaturation ratio to avoid homogenous nucleation.

The degree of supersaturation is measured as a saturation ratio (P/Ps), which is defined as the actual vapor partial-pressure divided by the saturation vapor pressure for a given temperature:

P supersaturation = __ Ps

For a given saturation ratio, the vapor can condense onto particles only if they are large enough. The minimum particle size capable of acting as a condensation nucleus is called the Kelvin diameter and is evaluated from the following relationship:

P (4 M) saturation ratio = __ = exp Ps

_____



RTd

5-1

where  = surface tension of the condensing fluid

M = molecular weight of the condensing fluid R = universal gas constant

T = absolute temperature d = Kelvin diameter

The higher the saturation ratio, the smaller the Kelvin diameter. The saturation vapor pressure Ps is defined for a flat liquid surface. For a

round liquid surface, such as the surface of a droplet, the actual saturation vapor pressure is greater. In other words, the smaller the droplet, the easier it is for the vapor molecules to escape the liquid surface. The Kelvin diameter defines the critical equilibrium diameter at which a pure droplet is stable—there is neither condensation nor evaporation. Smaller liquid particles will evaporate and larger particles grow even larger by condensation. The larger particle will grow until the vapor is depleted, causing the saturation ratio to fall until it is in equilibrium with the particle droplet.

If the saturation ratio is controlled to a level below the critical saturation ratio—the point at which homogeneous nucleation takes place— condensation will not take place in a particle-free environment.

The lower size sensitivity of the counter is determined by the operating saturation ratio. For the counter this ratio is several hundred percent, whereas in the atmosphere, this ratio is only a few percent for water.



= density of the condensing fluid

History

Historically, the counter has been called a condensation nucleus counter (CNC). CNC technology uses three techniques to cool and supersaturate the condensing vapor: adiabatic expansion, two-flow mixing, and diffusional thermal cooling. The Model 3772/3771 CPC uses the latter.

Adiabatic Expansion CNC

The first CNC was developed over a century ago by John Aitken [1888]. His simple and completely mechanical device cooled water-saturated air by adiabatic expansion using a pump. The droplets were counted as they fell onto a counting grid and a calculation was made to determine the concentration of dust particles in the sample volume. He made several improvements to his invention and his portable dust counter was used for many years (Aitken [1890–91]).

5-2 Model 3775 Condensation Particle Counter

Other significant developments in adiabatic-expansion CNCs include the use of electrical photodetectors to measure the light attenuation from cloud formation (Bradbury and Meuron [1938], Nolan and Pollak [1946], Rich [1955], Pollak and Metneiks [1959]); the use of under- and overpressure systems; and automation using electrically controlled valves and flow systems. The amount of light attenuated from the droplet cloud is monotonically related to the concentration of particles and is calibrated either by manual counting techniques, calculated from theory of particle light-scattering, or by using an electrical classification and counting method (Liu and Pui [1974]). A historical review of the expansion CNCs is given by Nolan [1972], Hogan [1979], and Miller and Bodhaine [1982].

Two-Flow Mixing CNC

Another cooling method turbulently mixes two vapor-saturated flows, one hot and one cold, to rapidly cool and supersaturate the vapor (Kousaka et al. [1982]). The condensation and droplet growth are fairly rapid and uniform. The flows can be passed continuously (that is, non-pulsating) through the mixing chamber onto a single-particle-counting optical detector.

Diffusional Thermal CNC

A continuous-flow, diffusional, alcohol-based, thermal-cooling CNC (Bricard et al. [1976], Sinclair and Hoopes [1975], Agarwal and Sem [1980]) first saturates the air sample with alcohol vapor as the sample passes over a heated pool of liquid alcohol. The vapor-saturated air stream flows into a cold condenser tube where the air is cooled by thermal diffusion. The alcohol condenses onto the particles and the droplets grow to about 10 to 12 micrometers. The droplets are counted by a singleparticle-counting optical detector.

Continuous-flow, diffusional, water-based CPCs (TSI Model 3781, 3785, and 3786 WCPCs) were developed between 2003 and 2006. Using a patented technique (Technology from Aerosol Dynamic Inc., U.S. Patent No. 6,712,881), an aerosol sample is drawn continuously through a cooled saturator and then into a heated condenser, where water vapor diffuses to the centerline of the condenser faster than heat is transferred from the warm walls, producing supersaturated conditions for water vapor condensing onto the particles.

Model 3760, 3762, and 3010 was introduced in early 90s and was replaced by Model 3772/3771 in 2005. The 3772/3771 CPC works only in the single count mode at relatively high aerosol flow rates of 1.0 and 0.6 L/min respectively. The 3772/3771 CPC uses n-butyl alcohol as the working fluid and an external vacuum pump or source to drive the 1 L/min aerosol flow rate. The 3772/3771 can detect 10 nm particles at 50% detection efficiency.

For high-concentration measurements, a classical photometric lightscattering technique is used. The first commercial version of this type of CNC (TSI Model 3020) used n-butyl alcohol as the condensing fluid and

Technical Description 5-3

has a flow rate of 0.3 L/min. TSI’s Model 3020 CNC was replaced in 1988 by the Model 3022A, which was replaced again in 2005 by the Model 3775 CPC. Both the Model 3775 CPC and the 3785 Water-based Condensation Particle Counter use the photometric mode of operation to monitor high particle concentrations up to 107 particles/cm3. These CPCs are generalpurpose instruments suitable for a wide variety of applications.

The Model 3025 Ultrafine Condensation Particle Counter (UCPC) was developed in 1989 and was replaced by the Model 3776 UCPC in 2005. The 3776 has a lower size detection limit and a higher aerosol flow rate compared to the 3025A. Both the 3776 UCPC and 3786 UWCPC utilize sheath-air-flow design to lower the size detection limit. When growing the particles in the condenser chamber, the highest saturation ratio occurs on the centerline of the flow stream at some distance down the condensing tube (Stolzenburg [1988]). Although the saturation ratio is not uniform across the flow profile due to thermal gradients, the lower size-sensitivity can still be predicted and measured. Using sheath air, the UCPC confines the aerosol to the centerline of the condenser tube where level of supersaturation is the highest. The result is very high detection efficiency for small particles. The high sensitivity of the Model 3776 UCPC and the Model 3786 UWCPC makes them the only instruments of their kind that can detect particulates down to 2.5 nm. This makes them useful for atmospheric studies, nucleation, cleanroom monitoring, and basic aerosol research, etc. The sheath-air-flow design of the two CPCs also significantly reduces the response time for particle detection and particle diffusion losses. This occurs because aerosol particles are routed directly from the inlet to the condenser and optics, not through the saturator.

The Model 3781 WCPC is a small size and light weight instrument that detects particles down to 6 nm and operates in single count mode for concentrations up to 5  105 particles/cm3.

The Model 3007 CPC was developed in 2001. It is a hand-held, battery powered instrument with a size detection limit of 10 nm. It uses isopropyl alcohol as the working fluid.

Currently, five CPCs (Models 3772, 3775, 3776, 3785, and 3786) are also commonly used with submicron size-distribution measurement systems such as the Scanning Mobility Particle SizerTM (SMPSTM) Spectrometers (TSI Model 3936).

5-4 Model 3775 Condensation Particle Counter

Design of the CPC

The basic instrument consists of three major subsystems: the sensor, the microprocessor-based signal-processing electronics, and the flow system. The sensor and the flow system are described below.

Sensor

The sensor is made up of saturator, condenser, and optical detector, shown schematically in Figure 5-1. The sensor grows the sampled aerosol particles into larger droplets and detects them optically. The laminar aerosol flow enters the saturator section where it passes through a heated, liquid-soaked cylindrical wick. The liquid evaporates and saturates the air flow with butanol vapor. Butanol is replenished from a reservoir and a fill bottle.

The flow of combined aerosol and butanol vapor is then cooled using a thermoelectric device (TED) in the condenser. The vapor becomes supersaturated and condenses on the aerosol particles (condensation nuclei) to form larger droplets. The droplets pass from the condenser tube through a nozzle into the optical detector. Liquid that condenses on the walls of the condenser tube runs back down and is removed by the water removal system into the drain bottle when the system is ON. Otherwise, the liquid goes back into the saturator and is absorbed into the wick for reuse.

The sensor’s optical detector is comprised of a laser diode, collimating lens, cylindrical lens, collection lenses, and photodiode detector. The laser and collimating lens form a horizontal ribbon of laser light above the aerosol exit nozzle. The collection lenses and detector incorporate a pair of aspheric lenses that collect the light scattered by the droplets and focus the light onto a low-noise photodiode. A reference photodiode is used to maintain constant laser power output. The surface temperature of the optics housing is maintained at a higher level than the saturator to avoid condensation on the lens surfaces.

The Model 3772/3771 CPC operates in single particle count mode up to 104 particles/cm3. Rather than simply counting individual electrical pulses generated by light scattered from individual droplets, the CPC uses a continuous, live-time coincidence correction to improve counting accuracy at high particle concentrations. Coincidence occurs when the presence of one particle obscures the presence of another particle creating an undercounting error. “Live-Time Counting” is discussed later in Chapter 6. This option can be turned OFF by firmware command “SCC,0”.

Technical Description 5-5

Figure 5-1

Flow Schematic of the Model 3772/3771 CPC

5-6 Model 3775 Condensation Particle Counter

Critical Flow

528.0

pressure Critical

528.0

ONA







To achieve the 1.0 L/min critical aerosol flow through the sensor, an orifice is used, operated at the critical pressure ratio to provide a critical flow. Critical flow is very stable and is a constant volumetric flow, assuring accurate concentration measurements despite varied inlet pressure.

The critical pressure ratio is found by dividing the absolute pressure downstream of the orifice PD, by the absolute pressure upstream of the orifice PU. This ratio must be below 0.528 for air.

Values for pressures impacting CPC flow can be obtained using firmware commands for both 3772 and 3771 CPCs. They are also found on the Status menu on the front panel display for 3772. These pressures are identified as the Ambient pressure, the Orifice pressure, and the Nozzle pressure. The ambient pressure is typically the barometric pressure at the inlet. The orifice pressure is the differential pressure across the aerosol flow orifice. The nozzle pressure is the differential pressure across the nozzle. Figure 5-1 identifies the location of the pressure transducer sample ports.

To verify that critical pressure (therefore critical flow) is achieved under extremes in inlet resistance, determine the orifice upstream pressure from (A – N). The downstream pressure is the upstream pressure minus the orifice differential pressure (A – N – O).

Flow is critical if the following is true:

(5-1)

Vacuum source, either a central building vacuum or a stand-alone vacuum source (e.g., TSI Model 3032 Vacuum Pump), should provide at least 60 kPa (18 in. Hg) vacuum and 1.0 L/min critical volumetric flow at the inlet of each CPC supported. The flow in the CPC is regulated by a critical orifice. Changes in the inlet pressure will not affect the flow rate through the instrument. A vacuum source that can provide a higher volumetric flow (e.g., TSI Model 3033 Vacuum Pump) is needed when running multiple CPCs.

Technical Description 5-7

Counting Efficiency and R esponse Time of the 3772/3771 CPC

The 3772/3771 CPC has a D50 of 10 nm. D50 is defined as the particle diameter at which 50% of particles are detected. The curve fit shown in Figure 5-2 is based on testing of three 3772/3771 CPCs using sucrose particles generated by TSI Model 3480 Electrospray Aerosol Generator and size classified with TSI Model 3080 Electrostatic Classifier and Model 3085 Nano Differential Mobility Analyzer (DMA) . The counting efficiency is calculated by comparing the CPC readings to TSI Model 3068A Aerosol Electrometer readings.

Note the particle concentration measured by the CPC is the total number concentration of all particles that a CPC can detect. This measurement provides no size differentiation and it is not corrected using the CPC counting efficiency curve. When the 3772 CPC is used as part of a Scanning Mobility Particle Sizer (TSI Model 3936 SMPS), the counting efficiency curve is used to correct particle count data to provide particle size distribution.

The 3772/3771 CPC has a fast response time. T95, defined as the time it takes for the CPC reading to reach 95% of a concentration step change, is about 3 sec for the 3772/3771 CPC. Figure 5-3 shows the response time curves. The curves are based on averaging of three CPCs.

Figure 5-2

Counting Efficiency Curve of 3772/3771 CPC

5-8 Model 3775 Condensation Particle Counter

Figure 5-3

Response Time of 3772/3771 CPC

Technical Description 5-9

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5-10 Model 3775 Condensation Particle Counter

C H A P T E R 6

Particle Counting

This chapter discusses specific aspects of particle counting and particle count measurements performed using the Model 3772/3771 Condensation Particle Counter (CPC).

The Model 3772 CPC has two modes for particle counting:

 Concentration mode, where data is presented as particle concentration

in p/cc, updated each second on the display (the maximum time resolution is tenth of a second).

 Total Count Mode (Totalizer Mode), where total particle counts are

accumulated and presented each second.

The Model 3771 CPC has the Concentration mode and is capable of Total Count Mode using the Aerosol Instrument Manager® software. Concentration mode is commonly used for most applications. Total Count Mode is used at very low particle concentrations. Particles can be accumulated until a desired statistical accuracy is achieved. Refer to the section below discussing total count accuracy.

In the concentration mode, the CPC operates in the single count mode with continuous, live-time coincidence correction over the range between 0 and 104 particles per cubic centimeter.

Optical Detection

Submicrometer particles are drawn into the counter and enlarged by condensation of a supersaturated vapor into droplets that measure several micrometers in diameter. The droplets pass through a lighted viewing volume where they scatter light. The scattered-light pulses are collected by a photodetector and converted into electrical pulses. The electrical pulses are then counted and their rate (live-time corrected) is a measure of particle concentration.

6-1

Total Count Accuracy









sensor the inflow aerosol of volume

counts total

ionconcentrat

rateflow aerosoltime-live daccumulate

particles counted of number 1



At very low concentrations, the accuracy of the measurement in the singleparticle-counting mode is limited by statistical error. If the total number of particles counted in each time interval is very small, the uncertainty in the count is large. The relative statistical error of the count total count n by

In total count mode (or totalizer mode), the accuracy of the concentration is increased by sampling for a longer period and counting more particles. The concentration is calculated by:

where

Q = Aerosol flow rate, nominally 1000 cm3/min (16.7 cm3/sec). t = sample time in sec.

Live-Time Counting



is related to the

Coincidence occurs when more than one particle occupies the optical

sensing region simultaneously. The optical detector cannot discriminate between the particles and multiple particles are counted as a single particle. At higher particle concentrations, particle coincidence begins to significantly impact the measured concentration.

The CPC corrects for coincidence continuously with the instrument electronics performing a “live-time” correction. Live-time refers to the time between electrical pulses. This is the total measurement time interval minus the time during which the counter is disabled with one or multiple particles in the optical sensing volume (the Dead Time). The dead time

should not be included in the sample time since particles can’t be counted

during this time interval except the ones that are already in the viewing volume. The actual particle concentration therefore equals the number of counted particles divided by the live time and the aerosol flow rate.

To measure live time, a high-speed clock and accumulator are used. The accumulator adds up the live time and the counter adds up pulse counts. The particle concentration is then calculated by

This option can be turned off by firmware command “SCC,0”.

6-2 Model 3772/3771 Condensation Particle Counter

Coincidence Correction for Pulse Output

C a u t i o n

At concentrations above 10,000, two exclamation marks appear at the

sides of the concentration reading on the front panel of the 3772. If this occurs, the number of particles shown on the display could be lower than the actual concentration.

Live-time coincidence correction is not available if you are using the pulse output from the CPC which only provides raw counts of the particles. Concentration can be calculated using raw counts and the aerosol flow rate of the CPC. This concentration is only accurate for low particle concentrations when coincidence level is low, e.g., in clean air or after a filter. If the pulse output is used for higher concentration up to 104 particles/cm3, the following calculation improves the accuracy of the particle concentration obtained from pulse output:

Na = Ni exp (NaQp)

where Na = the actual concentration (particles/cm3)

Ni = the indicated concentration (particles/cm3) Q = 16.67 cm3/s

p = 0.35 microsecond is the nominal effective time each particle resides in the viewing volume

The Na in the exponent can be approximated by Ni. Table 6-1 shows the calculated coincidence for several concentrations.

Coincidence is 1-Na/Ni.

Table 6-1

Coincidence Levels Based on 0.35 µsec Pulse Width

Concentration Calculated Coincidence (particles/cm3) (%)

10 >.01 100 .06 1000 .59 5000 3.05 10000 6.4

Concentrations obtained from pulse width and coincidence-corrected with the above equation are slightly different from the live-time corrected concentrations on the front panel display. The former concentration is corrected based on nominal pulse width but the latter is corrected based on the actual pulse widths for particles. For concentrations above those in Table 6-1, contact TSI Incorporated for a more suitable particle counter.

Particle Counting 6-3

Particle Size Selector

The particle size selector (Model 376060 PSS) is an accessory (not included) to the Model 3772/3771 CPC to let you choose any of 11 cutoff sizes between 0.010 and 0.122 micrometer. The PSS uses a series of finemesh screens to remove small particles by diffusional capture. An additional set of diffusion screens (available separately, Model 376061) lets you select cutoff diameters up to 0.25 micrometer. The cutoff sizes listed below are calculated using efficiencies for 3772/3771 CPC and diffusion screens.

Diffusion Particle size cut, screens μm (50%)

0 0.010 1 0.020 2 0.031 3 0.041 4 0.052 5 0.062 6 0.072 7 0.083 8 0.092 9 0.102 10 0.112 11 0.122

6-4 Model 3772/3771 Condensation Particle Counter

C H A P T E R 7

Computer Interface and Commands

This chapter provides computer interface and communications information for the Model 3772/3771 Condensation Particle Counter (CPC). Information on the Flash Memory Card for the 3772 is also provided.

Computer Interface

This section includes descriptions on USB, Ethernet connections, RS-232, and the Flash Memory Card (3772 only).

USB

USB communications are provided with the 3772/3771 CPC, for use with the supplied Aerosol Instrument Manager® software. Simply connect the supplied USB cable to the instrument and computer having Windows®based operating system and the Aerosol Instrument Manager® software. Refer to the Aerosol Instrument Manager manual for specific system requirements, including operating system version.

Ethernet

The Ethernet port on the CPC can provide system status information over the internet and is updated every five seconds. Your web browser must support java plug-ins.

Network Setup

1. Connect the CPC to the network using an Ethernet cable and turn the instrument on.

2. On the computer that is connected to the same network using another Ethernet cable, run the device discovery program Discovery.exe found on the supplied Aerosol Instrument Manager® Software CD or in the folder where the Aerosol Instrument Manager software is installed. This Discovery.exe program will find CPC devices on the network.

Note: This program will only find CPCs that are on the same subnet.

Example: If the computer is at IP address 10.1.3.1, the device discovery program will find all CPCs on 10.1.3.x. Also, if the

7-1

Windows® firewall is enabled (on by default in service pack 2), the device discovery will not find any CPCs. Once the IP address is known, you can access the CPC from another subnet.

3. Select the device and choose Configure network settings.

Figure 7-1

Digi Device Discovery Screen

4. Talk with your network administrator to verify the correct network settings this device should operate at. If needed, the MAC address can be located on the back of the instrument or in this pop-up window. Fill in the appropriate information and click Save.

Windows is a registered trademark of Microsoft Corporation.

7-2 Model 3772/3771 Condensation Particle Counter

Figure 7-2

Configure Network Settings Screen

5. Close the device discovery program and restart the CPC. It takes about a minute for the Ethernet to initialize.

6. If the CPC is in the same subnet as the computer, start the device discovery program Discovery.exe and click on Open web interface. The username and password are “tsicpc” as shown below in Figure 7-3. If the CPC is not in the same subnet as the computer, type in the IP address in your web browser. Work with your network administrator to make sure the IP address is accessible from the network your computer is in.

Figure 7-3

Digi Connect ME Configuration and Management Screen

Computer Interface and Commands 7-3

7. From the web interface of the device discovery program or the web browser, you can monitor the status of the CPC.

Figure 7-4

Main Screen HTML Page

7-4 Model 3772/3771 Condensation Particle Counter

Flash Memory Card Specification (3772 only)

A file is created on the Flash Memory Card when the Data Logging option is turned ON from the front panel of the 3772. Each file will contain one hour of data, unless the run is stopped early with the STOP option. See

Chapter 4.

Each file has this format: LINE 1: “TSI CPC DATA VERSION 1”

LINE 2: start time of this file (the first number is the total number of seconds elapsed from midnight Jan. 1, 1970) LINE 3: data average interval in seconds LINE 4: Instrument model number, firmware version number, instrument serial number (result of the “RV” command) LINE 5: first data set LINE 6: second data set LINE X: last data set

The data sets are defined as counts, concentration, analog input 1, analog input 2, status. These data sets are saved every average interval so if the average interval was one minute, the counts would be total counts (coincidence-corrected) over the last minute, etc. Instrument operates in normal condition if the status bit shows zero. A nonzero status indicates that some operating parameters deviate from normal conditions. See RIE command in Appendix B.

Every time a user begins a new run, a unique file will be created with the date and time as the file name.

Www_Mmm_dd_hh_mm_ss_yyyy Where Www is the weekday, Mmm the month in letters, dd the day of the

month, hh_mm_ss the time, and yyyy the year.

Disclaimer: Due to the fact that the FAT file systems are by design not power fail-safe, if power is lost, part or all of the file system may be lost.

Note: Keep the amount of data stored in the flash memory card under

64 MB to avoid long overhead time before generating a new data file each hour in the card.

Flash Memory Card Formatting Issue

On Model 3772 CPCs shipped before January 2008, the unit’s internal flash memory card had a formatting issue. This caused the card to appear full when the number of logged data files got much above 100, which resulted in the unit freezing up at the end of taking run data. To solve this issue, follow the steps below to reformat the card.

1. Power on the instrument and connect a USB cable to it from your computer. The flash memory card will appear as a separate disk drive in Microsoft® Internet Explorer® browser.

Computer Interface and Commands 7-5

2. If you have any data on the flash memory card you want to save, you

C a u t i o n

Remove the flash memory card following the correct procedures:

1. Use Safely Remove Hardware option in Windows to disconnect the card reader from the computer—stop USB Mass Storage Device.

2. After the message Safe To Remove Hardware: The “USB Mass Storage Device” device can now be safely removed from the system appears, physically remove the flash memory card from the card reader.

Failure to follow these procedures may result in failure to log data with the flash memory card.

must copy it to a temporary directory on your computer, because the reformat will erase it from the flash card.

3. Put your cursor on the flash memory card’s drive letter in Microsoft® Internet Explorer® browser and right click. Select Format.

4. Under File System, make sure “FAT32” is selected. Click on Start.

5. When it is done reformatting, copy any files you saved back onto the flash memory card.

6. You can check the format type of the flash memory card at any time by right clicking on the drive letter in Microsoft® Internet Explorer® browser. Select Properties and look under File System.

RS-232 Serial Communications

The communications ports are configured at the factory to work with RS-232-type devices. RS-232 is a popular communications standard supported by many mainframe computers and most personal computers. The Model 3772/3771 CPC has two A-pin, D-type subminiature connectors on the back panel labeled Serial 1 and Serial 2. Figure 7-5 shows the connector pins on the serial ports; Table 7-1 lists the signal connections.

Note: This pin configuration is compatible with the standard IBM PC serial

cables.

Figure 7-5

RS-232 Connector Pin Designations

7-6 Model 3772/3771 Condensation Particle Counter

Commands

Table 7-1

Signal Connections for RS-232 Configurations

Pin Number RS-232 Signal

1 GND 2 Transmit Output 3 Receive Input 4 (Reserved) 5 GND 6 — 7 — 8 — 9 —

An external computer is connected to Serial 1 for basic instrument communications and when Aerosol Instrument Manager® software is used. Serial 2 is used for attaching another instrument. Read and write commands are sent and received from Serial 2 by the computer connected to Serial 1. Serial 1 and Serial 2 can have different baud rates and communications protocols. Normally, only Serial 1 is used.

All commands and responses, unless specified as binary-encoded, are sent or received as ASCII characters. All messages are terminated with a <CR> (0x0D) character. All linefeeds (0x0A) characters are ignored and none are transmitted. Commands are case insensitive. Backspace character (0x08) will delete previous characters in buffer.

In this specification, values enclosed by “<>” indicate ASCII

characters/values sent/received. For example, <,> indicates the comma was sent or received via the communications channel.

Integers are 32-bit values. Floating point are IEEE() 32-bit values. Integer and floating point values are ‘C’ string compatible ASCIIencoded. For example, an integer value of <11011100101110101001100001110110> binary, would be sent as <3703216246>.

When char, integer or hex-decimal data is sent with more than one digit, leading zeros should always be left off. If the value of the data is zero, then one zero must be sent. An exception is the value zero in real format, it should be sent as 00000E0.

The firmware commands are divided into the following categories:

 READ Commands  SET Commands  MISC (MISCELLANEOUS) Commands  HELP Commands

Computer Interface and Commands 7-7

READ commands are used to read parameter from the instrument (flow rates, pressures, temperatures, etc.). READ commands can be identified by a leading "R".

SET commands set an internal parameter to the value(s) supplied with

the command. Supplied parameters are always delimited by a “<,>”. SET

commands can be identified by a leading "S". The instrument will reply to all set commands with the string “OK” <CR>.

MISC (MISCELLANEOUS) commands will be used for calibration and SMPS mostly.

HELP commands. A list of firmware commands are accessible using the HELP command sent to Serial 1 of the CPC. The firmware commands are also listed in Appendix B. The commands can be used to read CPC data, instrument statuses, set instrument operating parameters, and send and receive data from another instrument attached to the Serial 2 port.

The instrument will reply with a serial string of "ERROR", if a command was not understood.

To use the HELP commands and the firmware commands, a program capable of sending and receiving ASCII text commands can be used. A terminal program such as “HyperTerminal” (supplied with Windows®) is appropriate.

Connect to Serial 1 of the Model 3772/3771 CPC and perform the following steps:

1. Open the HyperTerminal program by selecting:

Start|Programs|Accessories|Communications| HyperTerminal.

2. Enter a name for the connection, for example, TSI-3772.

7-8 Model 3772/3771 Condensation Particle Counter

Figure 7-6 Connection Description Screen

3. Enter the communications (COM) port.

Figure 7-7

Connect To Dialog Box

4. Enter the port settings described below and click OK.

Computer Interface and Commands 7-9

Figure 7-8

Port Settings Dialog Box

5. Under the settings tab, pick the ASCII Setup button and check the boxes shown below.

Figure 7-9

ASCII Setup Dialog Box

7-10 Model 3772/3771 Condensation Particle Counter

6. Now select File|Save As and save the file to the desktop for easy access.

7. Close the program and start it again from the desktop. It should automatically open a connection to the instrument.

8. Type in firmware commands to communicate with the CPC. A list of firmware commands can be obtained using the HELP commands or from Appendix B. To obtain the list from HELP command, select Transfer|Capture Text… and then HELP ALL in the terminal window lets you capture all the help commands to a text file for easy reference.

Computer Interface and Commands 7-11

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7-12 Model 3772/3771 Condensation Particle Counter

W A R N I N G

Procedures described below may require removal of the instrument

cover. The instrument must be unplugged prior to service to prevent possible electrical shock hazard.

W A R N I N G

Unplug the instrument prior to removing the cover to avoid potential of

exposure to laser radiation.

C a u t i o n

Whenever performing service on internal components avoid damage to

the EECPC circuitry by not stressing internal wiring, through bumping, snagging or pulling. Also use electrostatic discharge (ESD) precautions:

 Use only a table top with a grounded conducting surface.  Wear a grounded, static-discharging wrist strap

C H A P T E R 8

Maintenance and Service

This chapter is written for a service technician with skills in both electronics and mechanics. Static preventative measures should be observed when handling any printed circuit board connectors.

Regular maintenance of the Model 3772/3771 Condensation Particle Counter (CPC) will help ensure years of useful operation. The frequency of service depends on the frequency of use and the cleanliness of the air measured. This section describes how to check and service some components of the CPC.

You are encouraged to call TSI for assistance in performing special maintenance. It may also be helpful to have the technician, tools, and the CPC close to the telephone when discussing the problem with a TSI technician. Refer to this chapter for directions on contacting a technical resource at TSI.

8-1

Replacement Parts Kits

TSI Part No.

Name

Description

1031513

Replacement Filter Kit, CPC 3772 and 3771

Kit of all filters used within the CPC.

1031514

Replacement saturator wick kit, CPC 3772 and 3771

Two (2) replacement wicks and Orings for the removable saturator base.

1031515

Maintenance Kit Model, CPC 3772 and 3771.

All items listed above.

In addition to replacement parts found in your supplied accessory kit, replacement items are also available from TSI to keep your CPC operating for many years. Parts are available in kits listed below. Please contact your TSI representative for details and purchase of these items.

Table 8-1 3772/3771 CPC Maintenance and Replacement Kits

8-2 Model 3772/3771 Condensation Particle Counter

TSI Part No.

Name

Description

1031548

Fill/Drain Bottle Kit, CPC 3772 and 3771

Fill and drain bottles, bracket, vacuum drain cap, tubing and fittings.

1031492

Kit, Charcoal Filter, large, CPC

Five (5) large charcoal filters used to remove butanol from exhaust (~tenday effectiveness for each filter).

1031493

Kit, Charcoal Filter, small, CPC

Five (5) small charcoal filters used to remove butanol from exhaust (~twoday effectiveness for each filter).

Maintenance and Service 8-3

Draining Butanol from t he Butanol

5. A special vacuum drain bottle cap is provided in the accessory kit to facilitate butanol draining using a vacuum source. Figure 8-1 shows the special cap, which consists of a vacuum port and a Balston filter. The Balston filter provides a bypass flow path. Connect the external vacuum source to the vacuum port. Connect the drain line to the Drain port on the CPC. When drain valve is open and vacuum is applied, the vacuum helps to pull excess butanol from the internal butanol reservoir and the wick. Exhaust from the external vacuum source contains butanol vapor and must be directed away from work spaces.

6. The butanol reservoir in the 3772 and 3771 CPCs is much smaller than the reservoir in predecessor models 3010, 3760, or 3762. The total volume drained from the reservoir and tubing is typically less than 7 ml. During draining, Auto-Fill is automatically turned off.

Figure 8-1

Vacuum Drain Cap Assembly

Reservoir

Butanol must be drained from the butanol reservoir prior to removing the saturator base and wick from the bottom of the CPC. To drain the butanol reservoir:

1. Connect butanol drain bottle (from the accessories) to the drain fitting on the back of the CPC using the mating quick-connect fitting.

2. Place the drain bottle on the floor.

3. The Drain can be initiated by using the “SDRAIN” firmware command on 3771 or by using the User Settings menu on the 3772. Detailed instructions for initiating the manual Drain for the 3772 are provided in

Chapter 4.

4. The butanol drain valve will open. Often there is not a significant column of liquid in the butanol drain line to initiate flow from the butanol reservoir. Tipping the instrument toward the drain port and squeezing the butanol drain bottle will sometimes help start flow. When releasing the squeezed drain bottle, plug the hole on the bottle cap to create a vacuum and to initiate draining.

8-4 Model 3772/3771 Condensation Particle Counter

Note: When draining is stopped, the Auto-Fill must be turned on again

by selecting this option from the User Settings menu for 3772 or

through “SFill” firmware command for 3772 and 3771.

Restarting the CPC can also turn Auto-Fill on.

Whenever the instrument is turned on, the Auto-Fill is activated. Do not run the instrument with the saturator base and wick removed to prevent spilling butanol from the butanol reservoir.

Changing the Filters

The CPCs use three liquid filters. The liquid filters are for butanol fill, butanol drain, and the water removal system. The filter in the water removal system is called Micro-pump filter. These filters may require replacement at intervals that depend on usage. As a general estimate the butanol fill filter needs to be replaced after every 2000 hours of usage, while the other two are replaced only as needed. Replacement filters are supplied in the accessory kit and are available from TSI as maintenance kits. Refer to the earlier section Replacement Parts Kits.

Butanol Fill and Drain Filters

The butanol fill filter is found in the fill line leading from the butanol fill bottle to the fill solenoid valve. The butanol drain filter is found in the line between the reservoir and the drain solenoid valve (Figure 8-2).

Caution

1. Read warnings and cautions at the beginning of this chapter.

2. Unplug the instrument and lift off the cover by first removing the cover screws.

3. Find the filter shown in Figure 8-2.

4. Remove the tubing from the barbed fittings at the back and front of the filter.

5. Replace the filter with the 73 µm filter (P/N 1602088) found in the accessory kit. This filter has no preferred direction.

Figure 8-2

Replacing the Butanol Fill and Drain Filters

Maintenance and Service 8-5

Micro Pump Filter

MicroPump Filter

The Micro-pump is used to remove condensed water vapor before it contaminates butanol in the saturator. The micro-pump filter protects the pump from contamination which could impede its performance. This filter should generally be replaced only if it becomes blocked. A blocked micropump filter prevents condensate from being extracted.

When using the water removal feature it is advisable to check the drain tubing to the drain bottle to verify liquid movement. The liquid column will pulse a small amount toward the drain bottle, approximately once per second as the micro-pump actuates. If no pulsing occurs, first verify that the water removal feature is on (see User Settings in Chapter 4). If the feature is on and no liquid flows in the liquid column, the micro-pump filter needs to be changed.

1. Read the warnings and cautions at the beginning of this chapter.

2. Unplug the instrument and lift off the cover by first removing the cover screws.

3. Find the filter shown in Figure 8-3.

4. Remove the tubing from the barbed fittings at the back and front of the filter.

5. Replace the filter with the 25 µm filter (P/N 1500192) found in the accessory kit. This filter has no preferred direction.

Figure 8-3

Replacing the Micro Pump Filter

8-6 Model 3772/3771 Condensation Particle Counter

Removing and Installing t h e Saturator

C a u t i o n

Removing the saturator wick will cause butanol (butyl-alcohol) vapors to

diffuse into the work space. Wick replacement operations must be performed in a well ventilated area, ideally under a fume hood. If unfamiliar with butanol, refer to the Chemical Safety information at the front of this manual.

C a u t i o n

Whenever the instrument is turned on, the Auto-Fill is activated. Do not run the instrument with the saturator assembly removed to prevent spilling butanol from the butanol reservoir.

Wick

Tools Needed

Plastic bag with seal, Phillips-head screwdriver, and paper towels. Refer to

figures that follow.

To remove and reinstall the saturator wick, follow the instructions below.

1. Find a plastic bag with seal, suitable to hold the 3”  1.75” saturator wick. The wick will likely be wet with butanol when removed and needs to be placed in the bag immediately to reduce release of butanol vapors.

2. Connect the Drain Bottle to the drain port at the back of the instrument.

3. Initiate the Manual Drain option as described in “Draining Butanol from

the Butanol Reservoir” section.

4. Once drained, turn the CPC off and remove the vacuum source from the external vacuum port.

5. Remove the inlet screw indicated in Figure 8-4 on the front panel and pull out the inlet tube. The inlet tube will not pull all the way out. It will stop when it has cleared the saturator block, approximately half an inch.

Figure 8-4

Inlet Tube

Maintenance and Service 8-7

6. To access the saturator base on the bottom panel, tilt the CPC on its

7. Remove the three screws which hold the base in the saturator block as shown in Figure 8-5. Release the handle in the base by loosening the thumbscrew.

Remove

Screw

Release

Saturator

Figure 8-5

Wick Removal

8. Using the saturator handle, pull the saturator base straight out. The wick is attached and will be removed with the base. It will be snug but avoid using a twisting motion.

9. Remove the 2-inch screw securing the wick to the base as indicated in Figure 8-6. Pull the wick straight off the base. Avoid using a twisting motion because the wick is keyed onto the base with dowel pins and the soft wick material can rip.

Figure 8-6

Removing the Wick from the Saturator Base

side so it is lying on the table. Place paper towels on the table under the saturator base to absorb any butanol that spills out. Do not turn it upside down.

8-8 Model 3772/3771 Condensation Particle Counter

10. Place the wick in the plastic bag and seal the bag. Replace the

11. To install a wick back into the CPC, confirm that four O-rings on the

saturator base in the CPC prior to shipping. This will prevent the aerosol path from becoming contaminated. Re-secure the inlet tube. The wick can be dried by putting it in a vacuum for three hours. However, it is not necessary to dry the wick before putting it back into the saturator block after the shipment.

saturator base are in place and undamaged. Replacement O-rings are provided in the accessory kit if an O-ring on the saturator base becomes lost or damaged. Figure 8-7 shows the two outer O-rings (P/N 2501172, 2501569) and Figure 8-8 shows the two inner O-rings (P/N 2500021).

Figure 8-7

O-Rings on Saturator Base (P/N 2501172 and 2501569)

Figure 8-8

O-Rings on Saturator Base (P/N 2500021)

12. Slide the wick back onto the saturator base using the two dowel pins to key it. This will keep the holes aligned as the wick is replaced in the CPC. Replace the 2-inch screw and washer.

13. Keep the CPC turned off and the vacuum supply disconnected from the external vacuum port on the back panel. Tilt the CPC on its side to access the bottom panel. The CPC can lie flat on its side but do not turn it upside down.

14. Reinsert the wick and base and secure to CPC using the three screws indicated in Figure 8-5. In case the wick does not insert easily, follow these tips:

i. If the CPC has recently been turned off, the saturator may still be

warm. Let the saturator cool down to room temperature before inserting the wick.

ii. Apply Krytox O-ring grease (accessory kit) to the bottom O-ring

only. Do not use silicon-based O-ring grease.

15. Reinsert the inlet tube and secure the sleeve with the screw indicated in Figure 8-4.

Maintenance and Service 8-9

16. Turn on the instrument and use the Auto-Fill option to refill the reservoir with butanol. See “User Settings” in Chapter 4.

Verifying Flow Rate

To measure the instrument sample flow rate, connect a low pressure-drop flowmeter to the CPC inlet. A bubble flowmeter or a thermal flowmeter works best. A TSI mass flowmeter also works because it is corrected for atmospheric pressure to give volumetric flow. The flow rate should be

1.0 L/min (0.035 cfm) ±5 percent. If the flow rate is too low, the orifice or

nozzle may be plugged, the vacuum may be less than 18 inches of mercury, or the pressure drop of the test flowmeter may be too high. A clogged orifice or nozzle can be further verified by the pressure drop across the orifice or nozzle which can be read on the front panel display for the 3772 or through serial command for both 3772 and 3771. If you suspect a clogged orifice or nozzle, contact TSI for instructions.

Calibration

Aside from the optics alignment, the initial factory checkout of the electronics, and the periodic flow verification, the CPC requires no calibration. The flow is controlled by a critical orifice, and thus, no adjustments are needed. The minimum detectable particle size is controlled by the supersaturation ratio of the fluid vapor in the condenser. Since the fluid droplets grow to nearly the same size, there is no particle size discrimination by electrical pulse-height. Finally, the CPC is a singleparticle counter, there is no photometric calibration for concentration.

8-10 Model 3772/3771 Condensation Particle Counter

Correcting Flooded Optic s

Due to the nature of the reservoir in the CPC, the inlet tube must not be plugged for more than a couple seconds when the instrument is in operation. In addition, the instrument should not be tilted more than 10º when it is in operation. In these events the vacuum flow can draw fluid from the reservoir through the entire flow path, including the optics.

Usually the first sign of flooding is the particle concentration decreases or changes erratically. In addition, the vacuum may have trouble functioning, you may see fluid in the vacuum lines, or you may hear a slurping sound coming from the CPC.

If you suspect the CPC is flooded, shut off the vacuum pump or disconnect the vacuum system. Follow these steps to dry out the instrument:

1. Drain the reservoir following the steps in the “Draining Butanol from the

Butanol Reservoir” section in this chapter.

2. Remove the cover from the CPC.

3. Inspect all tubing to make sure that no fluid is in the lines. If there is, remove the tubing and blow out any fluid with clean, compressed air. Tubing needs to be removed prior to cleaning to avoid other parts, e.g., pressure transducer, that could be damaged by compressed air.

4. With fill bottle disconnected, run the CPC for 48 hours with vacuum to thoroughly dry out the optics.

5. Refill the CPC with clean working fluid.

6. While sampling room air, use an oscilloscope to check the pulse height

of the analog pulses from the CPC. See the “Viewing Analog Pulses”

procedure next in this chapter.

7. If the pulse height is not within a normal range, the CPC should be

returned to TSI to have the optics cleaned. Refer to “Returning the

CPC for Service” later in this chapter for directions on returning the

CPC to TSI.

Maintenance and Service 8-11

Viewing Analog Pulses

W A R N I N G

The use of controls, adjustments, or procedures other than those

specified in this manual may result in exposure to hazardous optical radiation.

C a u t i o n

Whenever performing service on internal components avoid damage to

the CPC circuitry by not stressing internal wiring, through bumping, snagging or pulling. Also use electrostatic discharge (ESD) precautions:

 Use only a table top with a grounded conducting surface.  Wear a grounded, static-discharging wrist strap

You may want to observe the pulse shape of droplets passing through the CPC optics by looking at the electronic signal produced in the photodetector. This signal is produced when detecting scattered light from the droplets passing through the laser beam. In general, the pulses will be fairly uniform in shape and size regardless of the initial size of the particles detected.

Notes: ❑ Viewing analog pulses should only be attempted by someone

who is familiar with the operation of the CPC and who is technically qualified.

❑ When removing the cover of the CPC, observe the laser

warning label on the inside of the instrument.

Using an oscilloscope, observe the analog electrical pulses from the photodetector by following these steps:

1. Remove power from the CPC.

2. Remove the CPC cover.

3. Connect a “SMC Plug to BNC male” cable (not included) from J101 on the detector board to an oscilloscope as shown in Figure 8-9. The oscilloscope should be 50-ohm terminated. When viewing the signal on the scope, the signal height should be scaled down by a factor of 10. For a typical pulse of 3 volts, the scope will read only 300 mV.

8-12 Model 3772/3771 Condensation Particle Counter

Figure 8-9

Connecting SMC Plug to Detector Board

4. Apply power to the CPC. A typical analog pulse trace for 3772/3771 CPC is shown in

Figure 8-10. The minimum pulse amplitude is about 1 volt (100 mV on the oscilloscope) and the pulse width is about 0.30 microseconds. The pulse amplitude may range as high as 3.5 volts (350 mV on the oscilloscope).

Figure 8-10 Typical Analog Pulse Trace

Maintenance and Service 8-13

Calibration Reminder

TSI recommends yearly calibrations for your CPC. Ten months after the

instrument’s last calibration, a series of periodic reminders are generated

to notify the user that a yearly recalibration is due soon. These reminders come in two forms: a message appears on the screen (3772 only) and an error bit is set which is seen with the RIE firmware command. The message and bit will remain until cleared by either of these two methods: pressing a front panel key (3772 only), or sending the SCCR firmware command. After this, the reminder remains cleared until either another one is generated in several days, or the last reminder is given, or the unit is recalibrated. Be aware this is only a reminder and will not affect the operation of your instrument in any way, even if it is not recalibrated.

Although not necessary, if you wish to check the instrument’s last

calibration date or reminder status, use the SCD firmware command, which is explained in the appendix.

False Count Check

If you find that the CPC is continually counting a lot of particles even with a high efficiency (HEPA or ULPA) filter on the inlet, the CPC may have developed a leak or the aerosol flow path may have become contaminated with butanol.

To eliminate the possibility of butanol contamination, follow the directions for “Correcting Flooded Optics” in this chapter. If the false count problem continues, it is most likely due to a leak. If the wick has recently been replaced, confirm that the aerosol inlet is secured on the front panel.

If the false count problem continues, return the CPC to TSI for service.

8-14 Model 3772/3771 Condensation Particle Counter

Error Messages and Tro ubleshooting

Problem

Description

Problems/Suggestions

Concentration out of range

Concentration is higher than 104 particles/cm3

Concentration entering the CPC is too high. Dilute the aerosol before it enters the CPC.

Saturator temp out of range

Saturator temperature out of range ~±0.5 degrees C.

Warm up is not complete, instrument is operating in an environment outside its specified operating range (10 to 35 C), or instrument was removed recently from a temperature extreme.

Place instrument in an appropriate environment, allow temperature to stabilize.

Condenser temp out of range

Condenser temperature out of range ~±0.5 degrees C.

Warm up is not complete, instrument is operating in an environment outside its specified operating range (10 to 35 C), instrument was removed recently from a temperature extreme, or fan flow is impaired.

Place instrument in an appropriate environment, allow temperature to stabilize. Clean or replace fan filter, remove object blocking fan flow

Optics temp out of range

Optics temperature out of range ±2 degrees C.

Warm up is not complete, instrument is operating in an environment outside its specified operating range (10 to 35 C), or instrument was removed recently from a temperature extreme.

Place instrument in an appropriate environment, allow temperature to stabilize.

Nozzle or orifice pressure getting near to out of range; aerosol flow rate getting near to out of range –

Indicated by a ‘?’ instead of a ‘!’ on the

display.

The orifice and/or nozzle flow is getting close to being out of range. This uses tighter criteria

than the “Nozzle or orifice pressure out of range” condition

described in the next row, so it is a warning and not an error.

Apply sufficient external vacuum. Contact a TSI service technician.

The table below provides basic information on the errors generated by the Model 3772/3771 CPC, and suggestions for corrective action.

When an error occurs, the status LED on the front panel of the CPC turns off. Status parameters can provide information for troubleshooting the error. On the 3772/3771, the RIE firmware command will list instrument errors. On the 3772, in addition, refer to the Status Screen for status errors (see Figure 4-8). An exclamation mark will appear next to the parameter which is out of range. For both CPCs, refer to the table below to help identify the problem.

When called upon to remove the cover for service in the troubleshooting table, follow instructions below:

1. Read warnings and cautions at the beginning of this chapter.

2. Unplug the instrument and remove the instrument cover screws before lifting off the cover.

Table 8-2

Troubleshooting

Maintenance and Service 8-15

Problem

Description

Problems/Suggestions

Nozzle or orifice pressure out of range; aerosol flow rate is out of range

Orifice pressure is <10 or >90 kPa; Nozzle pressure is <1 or >6 kPa.

Apply sufficient external vacuum. Contact a TSI service technician.

Flooded instrument

Butanol liquid is present in the instrument optics causing a variety of problems including erratic or very low concentration readings and/or changes in transducer pressure measurements.

Although the 3772 and 3771 CPCs have been designed to resist flooding, it can occur if the instrument is shipped without properly drying or removing a wet wick. Flooding can also occur if the inlet is blocked or the instrument is tipped during operation.

Once the instrument cover is removed, evidence of flooding is seen by examining tubing for the presence of liquid. Start by looking at tubing connected to the pressure transducers. Carefully remove and dry out wet tubing then replace. Note: Don’t dry the tubing in place to avoid damaging other parts in the CPC.

If flooding has occurred, it will be necessary to dry the optics block.* Begin by draining the butanol and removing the wick as described earlier. Replace the saturator base without replacing the wick. Turn the instrument on and make sure the external vacuum is on and the fill bottle is disconnected. Allow the instrument to operate for at least 20 hours. Refer to “Correcting Flooded Optics” for detailed instructions.

Status: Laser power low

Detector in the laser indicates low laser power.

Contact a TSI service technician.

Status: Liquid level low

Liquid level sensor in the reservoir does not detect the presence of butanol.

Verify that no liquid is present in the reservoir by taking off the cover of the CPC and looking through the reservoir window. If it is difficult to identify the liquid level, using a flash light and tipping the CPC a couple degrees are helpful. If no liquid level line is seen, check carefully to confirm that it is not overfilled, indicating a problem in the butanol level detection circuitry.

Add butanol to the fill bottle and connect the bottle at the quick connect fitting.

Make sure the Auto Fill Enable is selected ON in the User Settings menu (Figure 4-6).

Watch the reservoir to confirm that it fills then stops. If filling does not occur, the fill filter may need to be replaced. Refer to “Changing the Filters” presented earlier.

*Flooding can contaminate the lens surfaces in the optics block reducing signal strength and instrument sensitivity. Lens

cleaning is performed at the factory if flooding occurs. A noticeable change in instrument performance characteristics (e.g., lowered detected concentration) can indicate the need to return the instrument to TSI for maintenance.

8-16 Model 3772/3771 Condensation Particle Counter

Technical Conta c ts

 If you have any difficulty installing the CPC, or if you have technical or

application questions about this instrument, contact an applications engineer at TSI Incorporated, (651) 490-2811.

 If the CPC fails, or if you are returning it for service, visit our website at

http://rma.tsi.com or contact TSI at:

TSI Incorporated 500 Cardigan Road Shoreview, MN 55126 USA

Phone: +1-800-874-2811 (USA) or +1 (651) 490-2811 E-mail: technical.service@tsi.com

TSI GmbH Neuköllner Strasse 4 52068 Aachen GERMANY

Telephone: +49 241-52303-0 Fax: +49 241-52303-49 E-mail: tsigmbh@tsi.com Web: www.tsiinc.de

TSI Instruments Ltd. Stirling Road Cressex Business Park High Wycombe, Bucks HP12 3ST UNITED KINGDOM

Telephone: +44 (0) 149 4 459200 Fax: +44 (0) 149 4 459700 E-mail: tsiuk@tsi.com Web: www.tsiinc.co.uk

Maintenance and Service 8-17

Returning the CPC f o r Service

Before returning the CPC to TSI for service, visit our website at

http://rma.tsi.com or call TSI at 1-800-874-2811 (USA) or (651) 490-2811

for specific return instructions. Customer Service will need this information when you call:

 The instrument model number  The instrument serial number  A purchase order number (unless under warranty)  A billing address  A shipping address.

If you no longer have the original packing material, first protect the CPC by placing it inside a plastic bag. Then package the unit with at least 5" (13 cm) of shock absorbing/packaging material around all six sides of the CPC. The packaging material must be sufficient to completely protect the integrity of the CPC when dropped from a height of 30 inches (76 cm).

8-18 Model 3772/3771 Condensation Particle Counter

TSI Instruments 3772, 3771 Operation And Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

OPERATION AND SERVICE MANUAL

Manual History

Warranty

Laser Safety

Safety

Chemical Safety

C a u t i o n

W A R N I N G

Description of Safety L a bels

Caution or Warning Symbols

Labels

Contents

Figures

Tables

Purpose

Organization

About This Manual

Related Product Lite r ature

Submitting Comments

Product Description

How it Works

Packing List

Unpacking

Setting Up

Remove Protective Caps

Mounting the Bracket and Fill Bottle

Filling the Fill Bottle with Butanol

Connecting the Butanol Drain Bottle

Apply Power to the CPC

Supply External Vacuum to the CPC

Positioning the CPC

Model 3772 Front Panel

LCD Display and Keypad

Aerosol Inlet

Status Light

Particle Light

Flash Memory Card Slot

Model 3771 Front Pane l

Model 3772/3771 Back Panel

AC Connector and Switch

USB Communication Port

RS-232 Serial Connections

Analog Inputs

DMA/Analog Output and Pulse Output

Ethernet Communication Port

Butanol Fill Port

External Vacuum Port

Cover

Drain Port

Instrument Cooling Fan

Bottom Panel

Internal Instrument C o m ponents

Water Removal Pump

Filters

Valves

Pressure Transducers

Electronics Boards

Basic Instrument Fu n c tions

Concentration Measurement

Total Count Mode (3772 only)

Water Removal

Internal Data Logging (3772 only)

Remote Access of Instrument

External Vacuum Pump or Source

Flow Rate Control

Temperature Control

Inlet Pressure Measurement

Operating Precautions

Power Switch

Warm-up

Status Indicator

Particle Indicator

Communication

Model 3772 LCD Display and Keypad

Model 3772 Keypad Navigation

Concentration