Teledyne 4020 User Manual

Total Hydrocarbon Analyzer

INSTRUCTION, OPERATING, AND

MAINTENANCE MANUAL FOR

MODEL 4020

Standard Software Version

P/N M74661

4/05/2010 Rev 6

DANGER

Toxic and/or flammable gases or liquids may be present in this monitoring system.
Personal protective equipment may be required when servicing this instrument.
Hazardous voltages exist on certain components internally which may persist for

a time even after the power is turned off and disconnected.
Only authorized personnel should conduct maintenance and/or servicing. Before

conducting any maintenance or servicing, consult with authorized
supervisor/manager.

Teledyne Analytical Instruments i

Model 4020

Copyright © 2010 Teledyne Analytical Instruments

All Rights Reserved. No part of this manual may be reproduced, transmitted, transcribed,
stored in a retrieval system, or translated into any other language or computer language in
whole or in part, in any form or by any means, whether it be electronic, mechanical,
magnetic, optical, manual, or otherwise, without the prior written consent of Teledyne
Analytical Instruments, 16830 Chestnut Street, City of Industry, CA 91749-1580.

Warranty

This equipment is sold subject to the mutual agreement that it is warranted by us free from
defects of material and of construction, and that our liability shall be limited to replacing or
repairing at our factory (without charge, except for transportation), or at customer plant at
our option, any material or construction in which defects become apparent within one year
from the date of shipment, except in cases where quotations or acknowledgements provide
for a shorter period. Components manufactured by others bear the warranty of their
manufacturer. This warranty does not cover defects caused by wear, accident, misuse,
neglect or repairs other than those performed by Teledyne or an authorized service center.
We assume no liability for direct or indirect damages of any kind and the purchaser by the
acceptance of the equipment will assume all liability for any damage which may result from
its use or misuse.

We reserve the right to employ any suitable material in the manufacture of our apparatus,
and to make any alterations in the dimensions, shape or weight of any parts, in so far as
such alterations do not adversely affect our warranty.

Important Notice

This instrument provides measurement readings to its user, an d serves as a to ol by whic h
valuable data can be gathered. The information provided by the instrument may assist the user
in eliminating potential hazards caused by his process; however, it is essential that all
personnel involved in the use of the instrument or its interface be properly trained in the
process being measured, as well as all instrumentation related to it.

The safety of personnel is ultimately the responsibility of those who control process
conditions. While this instrument may be able to provide early warning of imminent
danger, it has no control over process conditions, and it can be misused. In particular, any
alarm or control systems installed must be tested and understood, both as to how they
operate and as to how they can be defeated. Any safeguards required such as locks, labels,
or redundancy, must be provided by the user or specifically requested of Teledyne at the
time the order is placed.

Therefore, the purchaser must be aware of the hazardous process conditions. The purchaser
is responsible for the training of personnel, for providing hazard warning methods and
instrumentation per the appropriate standards, and for ensuring that hazard warning devices
and instrumentation are maintained and operated properly.

Teledyne Analytical Instruments, the manufacturer of this instrument, cannot accept
responsibility for conditions beyond its knowledge and control. No statement expressed or
implied by this document or any information disseminated by the manufacturer or its
agents, is to be construed as a warranty of adequate safety control under the user’s process
conditions.

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Total Hydrocarbon Analyzer

Specific Model Information

The instrument for which this manual was supplied may incorporate
one or more options not supplied in the standard instrument. Commonly
available options are listed below, with check boxes. Any that are
incorporated in the instrument for which this manual is supplied are
indicated by a check mark in the box.

Instrument Serial Number: _______________________

Options Included in the Instrument with the Above Serial Number:

 Power Requirements: This instrument may be designed for

operation using a power source other than 115 VAC @ 60
Hz. If so, one of the boxes below will be checked indicating
the power requirements for your instrument.

 110 VAC @ 50 Hz
 115 VAC @ 50 Hz
 220 VAC @ 50/60 Hz
 Other: _______________

 Using Hydrogen as Sample: For applications where the

sample gas is hydrogen, the sample gas doubles as the fuel
for combustion. The gas connections made at the back panel
are slightly different for this configuration. Connect the
hydrogen sample gas to the sample input as usual. Connect a
nitrogen source at 40 psig to the fuel input. This is discussed
in the manual in the Installation section.

 Using Hydrogen as Fuel: For applications where the fuel is

hydrogen, the gas connections made at the back panel are

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Model 4020

slightly different. At the “FUEL” inlet, replace the “40%
H

/60% N2” with pure H2. This is discussed in the

2

Installation section.

 Special Analysis Ranges: this model 4020 has special

analysis ranges:
Range 1: ___________
Range 2: ___________
Range 3: ___________

 Auto-Calibration Module Option: This module consists of

solenoid for automatically selecting calibration or sample
flow to the analyzer and provides the user with the ability to
calibrate the analyzer on a user-programmed schedule.

 AP Options: Vented Sample System Covers; Perforated

covers have been installed over the sample system
compartment and analyzer top cover for venting purposes.

 Recommended warm-up period: hours
 Other:

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Total Hydrocarbon Analyzer

Safety Messages

Your safety and the safety of others is very important. We have
provided many important safety messages in this manual. Please read
these messages carefully.

A safety message alerts you to potential hazards that could hurt you
or others. Each safety message is associated with a safety alert symbol.
These symbols are found in the manual and inside the instrument. The
definition of these symbols is described below:

GENERAL WARNING/CAUTION: Refer to the
instructions for details on the specific danger. These
cautions warn of specific procedures which if not
followed could cause bodily Injury and/or damage the
instrument.

No

Symbol

CAUTION: HOT SURFACE WARNING: This warning is
specific to heated components within the instrument.
Failure to heed the warning could result in serious burns
to skin and underlying tissue.

WARNING: ELECTRICAL SHOCK HAZARD: Dangerous
voltages appear within this instrument. This warning is
specific to an electrical hazard existing at or nearby the
component or procedure under discussion. Failure to heed
this warning could result in injury and/or death from
electrocution.

Technician Symbol: All operations marked with this
symbol are to be performed by qualified maintenance
personnel only.

NOTE: Additional information and comments regarding
a specific component or procedure are highlighted in the
form of a note.

STAND-BY: This symbol indicates that the instrument is
on Stand-by but circuits are active.

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Model 4020

CAUTION: THE ANALYZER SHOULD ONLY BE USED FOR THE

PURPOSE AND IN THE MANNER DESCRIBED IN
THIS MANUAL.

IF YOU USE THE ANALYZER IN A MANNER OTHER
THAN THAT FOR WHICH IT WAS INTENDED,
UNPREDICTABLE BEHAVIOR COULD RESULT
POSSIBLY ACCOMPANIED WITH HAZARDOUS
CONSEQUENCES.

This manual provides information designed to guide you through the
installation, calibration and operation of your new analyzer. Please read
this manual and keep it available.

Occasionally, some instruments are customized for a particular
application or features and/or options added per customer requests.
Please check the front of this manual for any additional information in
the form of an Addendum which discusses specific information,
procedures, cautions and warnings that may be specific to your
instrument.

Manuals do get misplaced. Additional manuals can be obtained from
Teledyne at the address given in the Appendix. Some of our manuals are
available in electronic form via the internet. Please visit our website at:
www.teledyne-ai.com.

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Total Hydrocarbon Analyzer

Table of Contents

Safety Messages ........................................................................... v

List of Figures ............................................................................... xi

List of Tables ............................................................................... xii

Additional Safety Information .................................................. xiii

Procedure for Removal of Internal Inaccessible Shock Hazards xv

Introduction ................................................................................... 1

1.1 Main Features of the Analyzer 1

1.2 Principle of Operation 2

1.3 Analyzer Description 2

1.4 Applications 3

Operational Theory ....................................................................... 7

2.1 Introduction 7

2.2 Sample System 7

2.2.1 Input Porting 8

2.2.2 Sample Flow Control System 8

2.2.3 Fuel and Blanket Air Systems 8

2.2.4 Flame Ionization Detection Cell 9

2.3 Detection Cell 9

2.3.1 Electrometer-Amplifier 10

2.3.2 Anode Power Supply 11

2.3.3 Flame Guard Circuit 11

2.3.4 Flame Ignition Circuit 11

2.3.5 Proportional Temperature Control Circuit 11

Installation ................................................................................... 13

3.1 Unpacking the Analyzer 13

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Model 4020

3.2 Mounting the Analyzer 13

3.3 User Connections 14

3.3.1 Electrical Power Connections 14

3.3.2 Gas Connections 14

3.3.2.1 Vent Connections 16

3.3.3 Electrical Connections 16

3.3.3.1 Primary Input Power 17

3.3.3.2 Fuse Installation 17

3.3.3.3 50-Pin Equipment Interface Connector 17

3.3.3.4 Analog Output 18

3.3.3.5 Alarm Relays 20

3.3.3.6 Digital Remote Cal Inputs 21

3.3.3.7 Range ID Relays 23

3.3.3.8 Network I/O 23

3.3.3.9 Pin Out Table 23

3.3.4 RS-232 Port 25

3.3.5 Supporting Gases 26

3.3.5.1 Sample Gas 27

3.3.5.2 Effluent 27

3.3.5.3 Sample Bypass Vent 27

3.3.5.4 Fuel and Air Connections 27

Operation ..................................................................................... 29

4.1 Equipment 29

4.2 Preliminary Power-Off Check List 30

4.3 Placing the System in Operation 30

4.4 Activating the Support Gases 31

4.4.1 Air 31

4.4.2 Sample Gas 31

4.4.3 Span Gas 31

4.4.4 Fuel 31

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4.5 Flame Ignition 32

4.5.1 Verification of the Flame Guard Circuit 32

4.5.2 Ignition and/or Flame Guard Circuit Failure 33

4.6 Analyzer Operation 33

4.6.1 Default Parameters 34

4.6.2 Style Conventions 34

4.6.3 Using the Controls 35

4.6.4 Mode/Function Selection 35

4.6.4.1 Analysis Mode 36

4.6.4.2 Setup Mode 37

4.6.5 Data Entry 38

4.6.5.1 ENTER 38

4.6.5.2 ESCAPE 38

4.6.6 Setting up an AUTO-CAL 40

4.6.7 Password Protection 42

4.6.7.1 Entering the Password 43

4.6.7.2 Installing or Changing the Password 44

4.6.8 Logging Out 45

4.6.9 System Self-Diagnostic Test 45

4.6.10 The Model Screen 46

4.6.11 Zero and Span Functions 47

4.6.12 The Alarms Function 50

4.6.13 The Range Function 53

4.6.13.1 Manual (Select/Define Range) Screen 53

4.6.13.2 Auto Range 55

4.6.13.3 Digital Mode 56

4.6.14 Digital Filter Setup 57

4.6.15 Fuel Display 58

4.6.16 Valve Selections 58

4.6.16.1 Disabled 59

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Model 4020

4.6.16.2 User Select 59

4.6.16.3 Default (By Function) 61

4.6.16.4 Observing the gas Stream Concentrations 62

4.6.17 Standby 63

4.7 Advanced User Functions 63

4.7.1 Zero Offset Adjustment 64

4.7.2 Background Gas Selection 65

Maintenance & Troubleshooting ................................................ 67

5.1 Measuring Circuit Electrical Checks 68

5.1.1 Loss of Zero Control 68

5.1.2 Anode Voltage Check 69

5.1.3 Electronic Stability 70

5.1.4 Printed Circuit Board Replacement 70

5.1.5 Collector Cable 70

5.2 Temperature Control Electronic Check 71

5.3 Ignition and/or Flame Guard Circuit Checks 72

5.4 Sampling System 73

5.5 Printed Circuit Board Descriptions 73

5.5.1 Flame Guard and Anode Power Supply PCB 73

5.5.3 Proportional Temperature Controller PCB 74

5.5.4 Electrometer-Amplifier PCB 76

Appendix ...................................................................................... 79

Specifications 79
Application Data 80
Recommended Spare Parts List 81
Drawing List 82

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Total Hydrocarbon Analyzer

List of Figures

Figure 1-1: Gas Sample System with Optional AutoCal Valves ...... 4

Figure 1-2: Gas Sample System Without Optional AutoCal Valves . 5

Figure 1-3: Flame Ionization Cell ..................................................... 6

Figure 2-1: View Inside Cabinet .................................................... 10

Figure 3-1: Gas Connections ......................................................... 15

Figure 3-2: Equipment Interface Connector Pin Arrangement ....... 18

Figure 4-1: Front Panel View of Regulator and Gages .................. 32

Figure 4-2: Typical VFD Screen Layout ........................................ 35

Figure 4-3: Setup Mode Functions ................................................ 39

Figure 4-4: AUTOCAL Screens ..................................................... 42

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Model 4020

List of Tables

Table 3-1: Analog Output Connections ......................................... 18

Table 3-2: Analog Concentration Output—Example ...................... 19

Table 3-3: Analog Range ID Output—Example ............................. 20

Table 3-4: Alarm Relay Contact Pins ............................................ 21

Table 3-5: Remote Calibration Connections .................................. 22

Table 3-6: Range ID Relay Connections ....................................... 23

Table 3-7: Pin out of 50 pin D-Sub Connector ............................... 24

Table 3-8: Commands via RS-232 Input ....................................... 26

Table 3-9: Required RS-232 Options ............................................ 26

Table 4-1: Digital Range Selection Signals ................................... 56

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Total Hydrocarbon Analyzer

Additional Safety Information

DANGER

COMBUSTIBLE GAS USAGE

This is a general purpose instrument designed for usage in a
non-hazardous area. It is the customer's responsibility to
ensure safety especially when combustible gases are being
analyzed since the potential of gas leaks always exist.

WARNING

The customer should ensure that the principles of operating
of this equipment are well understood by the user. Misuse of
this product in any manner, tampering with its components,
or unauthorized substitution of any component may
adversely affect the safety of this instrument.

Since the use of this instrument is beyond the control of
Teledyne, no responsibility by Teledyne, its affiliates, and
agents for damage or injury from misuse or neglect of this
equipment is implied or assumed.

WARNING: HYDROGEN GAS IS USED IN THIS INSTRUMENT AS

A FUEL. HYDROGEN IS EXTREMELY FLAMMABLE.
EXTREME CARE MUST BE USED WHEN WORKING
AROUND GAS MIXTURES CONTAINING
FLAMMABLE GASES.

A Successful leak check was performed at TI/AI on
the sample system of this instrument prior to
calibration, testing and shipping. Ensure that there
are no leaks in the fuel supply lines before applying
power to the system.

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Model 4020

Always purge the entire system before performing
any maintenance and always leak check the system
after removing any tubing or fittings on the sample
system. See the procedures for purging and leak
checking this instrument on the following pages.

If toxic gases or other hazardous materials are
introduced into the sample system, the same
precautions regarding leak checking and purging
apply to the sample lines and sample supply or
delivery lines.

WARNING: ELECTRICAL SHOCK HAZARD. WITH THE

EXCEPTION OF OPENING THE DOOR AND
ADJUSTING THE PRESSURE REGULATORS, FLOW
CONTROLLER, OR OBSERVING THE PRESSURE
GAUGES AND THE FLOWMETER, ONLY
AUTHORIZED AND SUITABLY TRAINED
PERSONNEL SHOULD PERFORM WORK INSIDE OF
THE INSTRUMENT. COMPONENTS WITHIN THE
COVER ON THE INSIDE OF THE DOOR, INSIDE THE
ISOTHERMAL CHAMBER (SAMPLE SYSTEM), AND
ON THE ELECTROMETER-AMPLIFIER PC BOARD
CONTAIN DANGEROUSLY HIGH VOLTAGE
SUFFICIENT TO CAUSE SERIOUS INJURY OR
DEATH.

There are the following three types of inaccessible

shock hazards within the 4020:

1. Line voltages and line related voltages such as
115 VAC which exists within the 230 VAC version
as well. These voltages stop when the 4020 is
turned off and the mains (line) cord is removed
from the instrument.

2. The sensor anode supply voltage (approximately
250 VDC). This voltage exists on the Flame
Guard, anode power supply, PCB, the
motherboard, and the anode/igniter terminals on
the sensor. THIS VOLTAGE WILL REMAIN
HAZARDOUS FOR MANY MINUTES AFTER THE
MODEL 4020 HAS BEEN TURNED OFF!

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Total Hydrocarbon Analyzer

3. External hazardous voltages which may be
connected to the Model 4020 alarm relay
connections.

Procedure for Removal of Internal Inaccessible
Shock Hazards

CAUTION: SERVICING OR MAINTENANCE OF THE 4020

SHOULD ONLY BE DONE BY SUITABLE TRAINED
PERSONNEL. TO AVOID THESE INACCESSIBLE
HAZARDOUS VOLTAGES WHEN SERVICING THE
4020, PERFORM EACH OF THE FOLLOWING STEPS,
IN THE ORDER GIVEN, BEFORE SERVICING
BEGINS:

1. Switch off the power to the 4020 and remove the mains (line)

power cord from the 4020.

2. Remove all external voltages from the connections to the

alarm contacts.

3. Wait one minute.

4. Discharge the anode supply voltage.
a. Connect one end of an insulated (to 1000 VDC or more)

clip lead to 4020 chassis ground (the standoff for the
upper right corner of the mother PCB).

b. Put one end of a 500V rated 1000 ohm resistor in the

other end of the clip lead.

c. Check the voltage between chassis ground (the standoff

for the upper right corner of the mother PCB) and the top
side of R2 at PCB number B74671. It should be between

-5VDC and +5VDC. If is in that range, the inaccessible
hazardous voltage removal procedure is completed, if not
repeat steps 4.a and 4.b.

If it is absolutely necessary to work inside the instrument with power

on, use the ONE HAND RULE:

Work with one hand only.

Keep the other hand free without contacting any other object. This
reduces the possibility of a ground path through the body in case of
accidental contact with hazardous voltages.

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Model 4020

WARNING: THIS INSTRUMENT IS DESIGNED TO BE OPERATED

IN A NONHAZARDOUS AREA. THE ANALYZER USES
HYDROGEN GAS AND/OR OTHER COMBUSTIBLE
GASES IN ITS OPERATION. THIS EQUIPMENT, IF
NOT USED AND MAINTAINED PROPERLY CAN BE
AN EXPLOSION HAZARD. THE ANALYZER,
DEPENDING ON THE APPLICATION, MAY ALSO USE
TOXIC GASES. IT IS THEREFORE, THE
CUSTOMER'S RESPONSIBILITY TO ENSURE THAT
PROPER TRAINING AND UNDERSTANDING OF THE
PRINCIPLES OF OPERATION OF THIS EQUIPMENT
ARE UNDERSTOOD BY THE USER. SINCE THE USE
OF THIS INSTRUMENT IS BEYOND THE CONTROL
OF TELEDYNE, NO RESPONSIBILITY BY TELEDYNE,
ITS AFFILIATES AND AGENTS FOR DAMAGE OR
INJURY RESULTING FROM MISUSE OR NEGLECT
OF THIS INSTRUMENT IS IMPLIED OR ASSUMED.
MISUSE OF THIS PRODUCT IN ANY MANNER,
TAMPERING WITH ITS COMPONENTS OR
UNAUTHORIZED SUBSTITUTION OF ANY
COMPONENT MAY ADVERSELY AFFECT THE
SAFETY OF THIS INSTRUMENT.

CAUTION: WHEN OPERATING THIS INSTRUMENT, THE DOORS

MUST BE CLOSED AND ALL COVERS SECURELY
FASTENED. THE GAUGES MUST BE IN PROPER
WORKING ORDER. DO NOT OVERPRESSURIZE THE
SYSTEM.

READ THIS MANUAL BEFORE OPERATING THE

INSTRUMENT AND ADHERE TO ALL WARNINGS
INCLUDED IN THIS MANUAL.

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Total Hydrocarbon Analyzer Introduction

Introduction

Teledyne Analytical Instruments Model 4020 Total Hydrocarbon
Analyzer is a versatile instrument designed to measure the quantity of
hydrocarbons present in a positive pressure sample as equivalent
methane. The Model 4020 is a microprocessor controlled digital
instrument based on Teledyne’s highly successful Model 402R series
analog Total Hydrocarbon Analyzer.

1.1 Main Features of the Analyzer

The Model 4020 Total Hydrocarbon Analyzer is sophisticated yet
simple to use. A dual display on the front panel prompts and informs the
operator during all phases of operation. The main features of the
analyzer include:

 Easy-to-use front panel interface that includes a red 5-digit

LED display and a vacuum fluorescent display (VFD), driven
by microprocessor electronics.

 High resolution, accurate readings of concentration from low

ppm levels to 6%.

 Microprocessor based electronics: 8-bit CMOS

microprocessor with 32 kB RAM and 128 kB ROM.

 Versatile analysis with three user-definable analysis ranges

from 1 ppm through 6%.

 Autoranging allows analyzer to automatically select the

proper preset range for a given measurement. Manual
override allows the user to lock onto a specific range of
interest.

 A digital mode for range selection allows the user to perform

range switching using the remote calibration contacts.

 O2/N2 background gas selection allows the use of two

different sample background gases with separate calibration
parameters stored in memory.

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Introduction Model 4020

 Two adjustable concentration alarms and a system failure

alarm.

 Extensive self-diagnostic testing at startup and on demand

with continuous power supply monitoring.

 RS-232 serial digital port for use with a computer or other

digital communication device.

 Analog outputs for concentration and range identification (0-

1 VDC standard and isolated 4-20 mA dc).

 Superior Accuracy

1.2 Principle of Operation

The sample gas is mixed with a fuel (normally a composition of
hydrogen and nitrogen) and burned in an atmosphere of “blanket air”.
The ions formed in the burning process cause an electrical conduction
between two electrodes in the combustion chamber (or detector cell) that
is amplified by a highly sensitive electrometer-amplifier circuit. The
electrical output of the electrometer-amplifier is directly proportional to
the quantity of flame ionizable hydrocarbons present, and is linear over
the range of 0-60,000 PPM methane.

1.3 Analyzer Description

The information contained in this manual describes individual analyzers
of the Model 4020 standard series. The versatility of this analyzer is inherited
through the long heritage of the earlier analog unit. Very often, special
customer driven design features are incorporated and will require additional
or supplementary information in addition to the information described in this
manual. These special considerations, if applicable, will be described in detail
on specific application pages as Addenda to this manual. When the Model
4020 is a part of a larger system, it is subordinate to that system, and specific
installation and operation conditions of that system will apply. Consult
system sections of the manuals for those applications, where conditions
specific to those systems will be detailed.

To best suit the needs of the purchaser, specialized designs may have
been adopted. Details of the design differences may be found in the
various drawings (outline, assembly, schematic, wiring, and piping
diagrams) in the drawings section at the rear of the manual.

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Total Hydrocarbon Analyzer Introduction

The standard analyzer is housed in a sheet steel equipment case
flush-mounted in a 19" rack. The front interface panel is mounted on a
door which, when opened, allows convenient access to the 4020
electronics. The entire front panel can slide out of the chassis to provide
greater access to the electronics and to the sample system. Gas pressure
and flow controls are mounted on the front panel adjacent to the LED
and VFD displays and user interface.

At the rear of the instrument are ports for the introduction of air,
fuel, zero, span, and sample gas. A single 50-pin user-interface cable
connector contains input/output and alarm signals available to the user.
An RS-232 port is also available at the rear panel for connection to a
remote computer or other digital communication device. The Model
4020 is set up for either 120 VAC 60 Hz or 230 50/60 Hz operation
depending on the customer’s requirements. The appropriate power cord
for your unit has been shipped with this instrument.

1.4 Applications

 Monitoring the purity of oxygen, argon, nitrogen and other

gases in the manufacture of semiconductors and related
equipment.

 Monitoring hydrocarbon contamination in air liquefaction

and other gas production processes.

 Gas purity certification.
 Detecting trace hydrocarbons in ambient air.
 Detecting atmospheric pollutants.
 Cryogenics.
 Monitoring for fuel leakage or toxic solvents.
 Monitoring hydrocarbons in a wide range of process streams.

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Introduction Model 4020

Figure 1-1: Gas Sample System with Optional AutoCal Valves

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Total Hydrocarbon Analyzer Introduction

Figure 1-2: Gas Sample System Without Optional AutoCal Valves

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Introduction Model 4020

Figure 1-3: Flame Ionization Cell

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Total Hydrocarbon Analyzer Operational Theory

Operational Theory

2.1 Introduction

The Model 4020 Total Hydrocarbon Analyzer is composed of three
subsystems:

1. Sample System

2. Detector Cell

3. Electronic Signal Processing, Display and Control

2.2 Sample System

Note: The measured component for the Model 4020 is

hydrocarbon content. Hydrocarbon lubricants and
conditioners, as well as synthetic plastics are common to
instrumentation supply processes. Utmost precaution must
be taken at all times to specify hydrocarbon-free gases,
regulator diaphragms, and supplies.

All components used to control the sample and supporting gases, as
well as the combustion portion of the detector cell, are located inside the
enclosure, behind the electronics control panel and are accessible by
sliding the front of the unit out from the rack enclosure. Adjustments are
made using the appropriate control on the front panel.

The software in the Model 4020 allows the system to be used for
analyzing a sample gas in two different backgrounds, O
separate calibration must be performed on each sample/background
combination. The calibration parameters are stored internally and are
appropriately applied when the user selects the specific background gas
in use. See Section 4.7.2 Background Gas Selection.

Note: The user must supply the necessary valves and any

associated switching equipment for delivering the correct
sample/background gas combination to the analyzer.

and N2. A

2

Teledyne Analytical Instruments 7

Operational Theory Model 4020

The basic analyzer consists of an isothermal chamber containing the
pressure regulators, pressure gauges and flow restrictors. The
temperature within the chamber is maintained at 125°F by a heating
element. The regulated temperature of the chamber insures stable gas
flow. An optional AutoCal module is available which when fitted,
mounts inside the instrument enclosure and integrates with the sample
system. It allows convenient switching between sample and calibration
gases. When installed, it is part of the isothermal chamber. The bypass
flow is also controlled from this optional panel.

2.2.1 Input Porting

The analyzer is equipped with ports for the introduction of air, fuel,
zero, span, and sample gas.

2.2.2 Sample Flow Control System

Stable sample flow is achieved by maintaining a constant pressure
across a restrictor through the use of a back-pressure regulation system,
which includes an adjustable regulator, pressure gauge, throttle valve,
and flowmeter. The throttle valve and flowmeter are included so that the
bypass flow required by the back-pressure regulator can be limited.
Without these controls, a high sample point pressure would result in
unnecessary sample waste through the back-pressure regulator.

The components of the system are arranged so that no dead volume
is present in the sample path to the detector cell. This guarantees rapid
response to changes in hydrocarbon concentration—a fact that can be
demonstrated when zero and span gas are exchanged during the
standardization procedure.

The restrictors used in the system look alike; however, they are not
interchangeable.

2.2.3 Fuel and Blanket Air Systems

The fuel and blanket air systems use similar components. Stable flow
is achieved by maintaining a constant pressure across restrictors upstream
from the cell. Each system incorporates an adjustable pressure regulator,
pressure gauge, and restrictor. A flame out light is included to indicate
when the flame fails. A fuel shut-off solenoid valve, mounted on the line
that supplies fuel, stops the fuel flow in case of flame failure. This valve is
located in line with the fuel port; except for instruments using hydrogen as
the sample gas. In this case, the sample is used as fuel and the valve is

Teledyne Analytical Instruments 8

Total Hydrocarbon Analyzer Operational Theory

located in line with the sample port. See Figure 1-1 for a flow schematic
for instruments equipped with AutoCal valves and Figure 1-2 for
instruments without the AutoCal option.

2.2.4 Flame Ionization Detection Cell

The sample and fuel are combined within a tee fitting located in the
isothermal chamber. The mixed gas is emitted from a burner within the
sensor assembly. Blanket air is introduced into the sensor (or cell) by
means of a separate fitting that is located in the base section of the
assembly. The upper half of the assembly houses the anode-igniter,
collector, and flame guard thermistor. The cell is located at the left hand
front area inside the enclosure for easy access. See Figure 2.1.

2.3 Detection Cell

The upper section of the stainless steel flame ionization cell houses
the cylindrical collector electrode, the high voltage (+260 VDC) anode­igniter coil, and the sensing thermistor of the flame guard circuit (see
cell cross-section Figure 1-3).

WARNING: DANGEROUS HIGH VOLTAGE EXISTS AT THE

ANODE IGNITER COIL (+260 VDC). DO NOT
ATTEMPT TO DISCONNECT THE IGNITER COIL
CABLE OR DISASSEMBLE ANY OF THE FLAME
IONIZATION CELL COMPONENTS WITHOUT
TURNING OFF THE POWER AND DISCONNECTING
THE POWER CORD.

The collector is interconnected with the electrometer-amplifier PC
board by a coaxial cable. Although the cable and fittings are intended for
coaxial service, the cable is actually being used as a shielded single­conductor connection.

The anode-igniter, as its name implies, serves two functions. When
relay K2 at PCB part number B74671 is energized, the coil becomes an
electrical heating element that glows red-hot and ignites the hydrogen
fuel. When relay K2 at B74671 is de-energized, the coil is connected to
the +260 volt DC terminal of the anode-flame guard power supply PC
board. In this configuration, the necessary potential difference is
established between the coil (anode) and collector to promote ionization
of the burned hydrocarbons. The coil functions as the high voltage anode
in all three range positions of the selector switch.

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Operational Theory Model 4020

The thermistor acts as the sensor in the flame guard circuit. Its
ambient temperature resistance is in the 100 K ohms region. When the
flame is ignited, its resistance is reduced by a factor of 100. The
thermistor is coupled to a semiconductor control circuit on the anode­flame guard power supply PC board, which will be described in a
following section.

The cell electrodes of both the anode-igniter and flame guard
thermistor are connected to the electronics chassis by means of a plug-in
cable.

The electrode section of the cell may be removed for inspection by
turning off the power, disconnecting the electrode lead plug, and
removing the screws which retain the electrode assembly in the sensor
body.

Figure 2-1: View Inside Cabinet

2.3.1 Electrometer-Amplifier

The collector cable is coupled directly to a coaxial fitting located on
the electrometer-amplifier PC board. The PC board is located on the side
panel next to but outside of the isothermal chamber. See Figure 2-1. and
consists of an electrometer amplifier and an operational amplifier. This
circuit is a very high-gain, current-to-voltage converter circuit, having

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Total Hydrocarbon Analyzer Operational Theory

an input impedance measuring in the billions of ohms. It is static
sensitive and highly susceptible to contamination. Special care must be
taken in handling this PC board.

Refer to Section 5.5.4: Electrometer-Amplifier PC Board for more
information concerning the electrometer-amplifier and the other printed
circuits that follow.

2.3.2 Anode Power Supply

The high voltage anode power supply components are mounted on
the anode power supply printed circuit board. High voltage regulation is
achieved through the use of series-connected zener diodes. The
simplicity of this circuit’s design can be attributed to the extremely low
current demand of the anode circuit. The positive output voltage is
nominally 125 volts. Output tolerance is ±10 volts from the specified
125 volts.

2.3.3 Flame Guard Circuit

A thermistor-controlled, transistorized switching circuit is employed
to operate a relay in the event of a flame-out condition. A panel indicator
light and fuel shut-off solenoid valve are operated by the relay to alarm
personnel that a flame-out condition has occurred. The fuel shut-off
solenoid valve stops the hydrogen flow.

2.3.4 Flame Ignition Circuit

The flame ignition circuit includes the anode-igniter electrode (in the
detector cell), a transformer, and processor controlled relay. The circuit
is automatically energized after the warm up count down timer expires.

If automatic ignition fails, there will be a message that reports this,
and the flame can be manually ignited by pressing simultaneously the
Up and Down key.

2.3.5 Proportional Temperature Control Circuit

The temperature of the isothermal chamber containing the sampling
components is regulated by a thermistor-directed electronic circuit. The
thermistor and heating element are located in the chamber, and the
balance of the circuit components are mounted on the temperature
controller printed circuit board. A temperature limit switch protects the

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Operational Theory Model 4020

isothermal chamber against excessive temperature, which may occur if
the temperature controlling system fails.

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Total Hydrocarbon Analyzer Installation

Installation

Installation of the Model 4020 Total Hydrocarbon Analyzer
includes:

1. Unpacking

2. Mounting

3. Gas connections

4. Electrical connections

5. Testing the system.

3.1 Unpacking the Analyzer

Although the analyzer is shipped with all the materials you need to
install and prepare the system for operation. Carefully unpack the
analyzer and inspect it for damage. Immediately report any damage or
shortages to the shipping agent.

3.2 Mounting the Analyzer

The Model 4020 is a general-purpose analyzer and as such is
designed with (non-sealed) enclosures. It must be installed in an area
where the ambient temperature is not permitted to drop below 32ºF nor
rise above 100ºF. In areas outside these temperatures, auxiliary
heating/cooling must be supplied. The 4020 enclosure is oil and dust
resistant and although it is designed to resist moisture, it should NOT be
considered completely watertight. Mounting to walls or racks must be
made securely. Avoid locations that are subject to extreme vibration and
sway.

Sufficient space must be provided around the analyzer to
accommodate the necessary electrical conduit and plumbing connections.
The front panel must be allowed to be pulled out for possible service
access to all components of the enclosure. Refer to the system/analyzer
outline drawings for dimensions.

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Installation Model 4020

Note: To completely slide the analyzer out of the enclosure, pull
analyzer out until it stops, then push down on the release levers found
almost at the end of the sliders, both sides at the same time.

Regardless of configuration, the analyzer/system must be installed
on a level surface with sufficient space allocated on either side for
personnel and test equipment access. Subject to the foregoing, the
analyzer/system should be placed as close to the sample point as is
possible.

All pertinent dimensions, connecting points, and piping details can
be found in the drawings section as part of the outline, input-output, and
piping diagrams. These drawings are specific to the instrument or
system to which the manual applies.

3.3 User Connections

All user connections are made on the rear panel. Consult the input­output and outline diagrams in the drawing section of the manual. Not
all the features displayed may be present in your system. Refer to any
Addenda for additional information that may apply to your instrument.

3.3.1 Electrical Power Connections

The standard analyzer requires a supply of 100-125VAC, single­phase power. Power connections are made at the rear panel of the unit.
Refer to the input-output diagram for more information. The electrical
power service must include a high-quality ground wire. A high-quality
ground wire is a wire that has zero potential difference when measured
to the power line neutral. If you have the 220 VAC option, you will
require 220 or 240 VAC, 50/60 Hz power. Check the analyzer input­output diagram, power schematic, outline, and wiring diagrams for
incoming power specifications and connecting points.

CAUTION: PRIMARY POWER TO THE SYSTEM SHOULD NOT

BE SUPPLIED UNTIL ALL CUSTOMER WIRING IS
INSPECTED PROPERLY BY START-UP PERSONNEL.

3.3.2 Gas Connections

The analyzer gas connection diagram identifies the various gas
connection points as to function and location. Figure 3-1 shows the gas
connection points for instruments with the optional AutoCal module.

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