Instruction Manual
748214-V
June 2009
Model 951C
NOX Analyzer
http://www.raihome.com
WORLD HEADQUARTERS
ESSENTIAL INSTRUCTIONS
READ THIS PAGE BEFORE PROCEEDING!
Rosemount Analytical designs, manufactures and tests its products to meet many national and
international standards. Because these instruments are sophisticated technical products, you
MUST properly install, use, and maintain them to ensure they continue to operate within their
normal specifications. The following instructions MUST be adhered to and integrated into your
safety program when installing, using, and maintaining Rosemount Analytical products. Failure to
follow the proper instructions may cause any one of the following situations to occur: Loss of life;
personal injury; property damage; damage to this instrument; and warranty invalidation.
• Read all instructions prior to installing, operating, and servicing the product.
• If you do not understand any of the instructions, contact your Rosemount Analytical
representative for clarification.
• Follow all warnings, cautions, and instructions marked on and supplied with the product.
• Inform and educate your personnel in the proper installation, operation, and
maintenance of the product.
• Install your equipment as specified in the Installation Instructions of the appropriate
Instruction Manual and per applicable local and national codes. Connect all products to
the proper electrical and pressure sources.
• To ensure proper performance, use qualified personnel to install, operate, update, program,
and maintain the product.
• When replacement parts are required, ensure that qualified people use replacement parts
specified by Rosemount. Unauthorized parts and procedures can affect the product’s
performance, place the safe operation of your process at risk, and VOID YOUR WARRANTY.
Look-alike substitutions may result in fire, electrical hazards, or improper operation.
• Ensure that all equipment doors are closed and protective covers are in place, except
when maintenance is being performed by qualified persons, to prevent electrical shock
and personal injury.
The information contained in this document is subject to change without notice.
Teflon® is a registered trademark of E.I. duPont de Nemours and Co., Inc.
Alconox is a registered trademark of Alconox, Inc.
SNOOP® is a registered trademark of NUPRO Co.
Emerson Process Management
Rosemount Analytical Inc.
6565P Davis Industrial Parkway
Solon, OH 44139
T 440 914 1261
T 800 433 6076
F 440 914 1262
E gas.csc@emerson.com
Instruction Manual
748214-V
Model 951C
June 2009
HIGHLIGHTS OF CHANGES
EFFECTIVE JUNE 10, 2009
PAGE SUMMARY
Cover Updated photo, revision number, and release date
P-6 Removed Compliance section
1-1 Added Mid Range
1-2 Added Mid Range
3-1 Added Mid Range, Backlight over range feature, and a note, using the MID
range, set the pressure regulator to 2.5 psig.
3-2 Added a photo of the Signal Board, Added a photo of the Signal Board Test
Points, removed the signal board diagnostic jumpers (Figure 3-4)
3-3 Removed the Hi/Lo Range Select Jumper (Figure 3-5), Updated the PPM Range
selection switch photo and table, removed the decimal point selection jumpers
(Figure 3-7), added Configuration Jumper Settings (Figure 3-7)
3-6 Added step 3 to the Zero Calibration Section (In the Mid Range Configuration,
Set the Sample Pressure Regulator to 2.5 psig), Added step 3 to the span calibration section (In the Mid Range Configuration, Set the Sample Pressure Regulator to 2.5 psig), Added step 6 to the span calibration section (Use R25 and R43
for fine adjustments to the display and recorder output.)
4-3 Updated the Signal Conditioning and Display section to reflect the current PCB’s,
updated the Circuit function section.
4-5 Updated the Analyzer Signal Conditioning Block Diagram
6-1 Updated the MATRIX
6-3 Updated the Replacement Parts List
List of Drawings Added Drawing 1-1, 1-2, and1-3
Back Cover Updated Company addresses and contact information
Rosemount Analytical Inc. A Division of Emerson Process Management Contents i
Instruction Manual
748214-V
June 2009
PREFACE...........................................................................................................................................P-1
Definitions ...........................................................................................................................................P-1
Safety Summary .................................................................................................................................P-2
General Precautions For Handling And Storing High Pressure Gas Cylinders .................................P-5
Documentation....................................................................................................................................P-6
Condensed Startup And Calibration Procedure .................................................................................P-7
1.0 DESCRIPTION AND SPECIFICATIONS..............................................................................1-1
1-1 Overview................................................................................................................................1-1
1-2 Typical Applications ...............................................................................................................1-1
1-3 Specifications.........................................................................................................................1-2
2.0 INSTALLATION ....................................................................................................................2-3
2-1 Unpacking..............................................................................................................................2-3
2-2 location ..................................................................................................................................2-3
1-3 voltage requirements .............................................................................................................2-3
1-4 Electrical Connections ...........................................................................................................2-3
a. Line Power Connections .................................................................................................2-3
b. Potentiometric Recorder Connections ............................................................................2-3
c. Current Recorder Connections .......................................................................................2-3
1-5 Gas Requirements.................................................................................................................2-5
a. Air (U.S.P. Breathing Grade) ..........................................................................................2-5
b. Span Gas ........................................................................................................................2-5
1-6 Sample Requirements ...........................................................................................................2-5
1-7 Gas Connections ...................................................................................................................2-5
1-8 Leak Test ...............................................................................................................................2-6
Model 951C
TABLE OF CONTENTS
3.0 OPERATION .........................................................................................................................3-1
3-1 Front Panel Indicators and Controls ......................................................................................3-1
a. Display ............................................................................................................................3-1
b. Range Selection..............................................................................................................3-1
c. Sample Pressure Gauge.................................................................................................3-1
d. Ozone Pressure ..............................................................................................................3-1
e. Zero and Span Potentiometers .......................................................................................3-3
f. Ozone Interlock ...............................................................................................................3-3
3-2 Startup Procedure .................................................................................................................3-3
3-3 Calibration..............................................................................................................................3-6
a. Zero Calibration...............................................................................................................3-6
b. Upscale Calibration .........................................................................................................3-6
3-4 Routine Operation .................................................................................................................3-6
3-5 Converter Temperature Adjustment Procedure ....................................................................3-6
3-6 Measurement of Converter Efficiency ...................................................................................3-9
3-7 Recommended Calibration Frequency ..................................................................................3-9
4.0 THEORY................................................................................................................................4-1
ii Contents Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
4-1 Nitric Oxide Determination by Chemiluminescence Method .................................................4-1
4-2 Analyzer Flow System ...........................................................................................................4-1
a. Flow of Sample, Standard Gas or Zero Gas to Reaction Chamber ...............................4-1
b. Ozone Generation...........................................................................................................4-1
4-3 Signal Conditioning And Display ...........................................................................................4-2
a. Circuit Functions .............................................................................................................4-2
4-4 Analyzer Thermal System .....................................................................................................4-3
5.0 ROUTINE SERVICING..........................................................................................................5-1
5-1 System Checks and Adjustments..........................................................................................5-1
a. Display Fullscale Span Adjustment.................................................................................5-1
b. Overall Sensitivity............................................................................................................5-1
c. Ozone Output..................................................................................................................5-2
d. Background Current ........................................................................................................5-2
5-2 Servicing Flow System ..........................................................................................................5-2
a. Cleaning Sample Capillary..............................................................................................5-3
b. Ozone Restrictor Fitting ..................................................................................................5-3
5-3 Photomultiplier Tube/Reaction Chamber ..............................................................................5-4
a. Removal ..........................................................................................................................5-4
b. Cleaning Reaction Chamber ...........................................................................................5-4
c. Photomultiplier Tube and Housing ..................................................................................5-5
d. Replacement of Photomultiplier Tube.............................................................................5-6
5-4 Ozone Generation System ....................................................................................................5-6
a. Lamp/Housing Removal..................................................................................................5-6
b. UV Lamp Replacement ...................................................................................................5-7
c. Power Supply Removal...................................................................................................5-7
5-5 Converter Assembly ..............................................................................................................5-7
5-6 Servicing Electronic Circuitry.................................................................................................5-8
Instruction Manual
748214-V
June 2009
6.0 REPLACEMENT PARTS ......................................................................................................6-1
6-1 Matrix .....................................................................................................................................6-1
6-2 Circuit Board Replacement Policy .........................................................................................6-3
6-3 Replacement Parts ................................................................................................................6-3
a. Common Parts ................................................................................................................6-3
b. Photomultiplier Assembly 654062...................................................................................6-4
c. Converter Assembly 654070...........................................................................................6-5
d. Temperature Control Assembly 654068 .........................................................................6-6
7.0 RETURN OF MATERIAL ......................................................................................................7-2
7-1 return of material ...................................................................................................................7-2
7-2 customer service ...................................................................................................................7-2
7-3 Training..................................................................................................................................7-2
8.0 INDEX....................................................................................................................................8-1
Rosemount Analytical Inc. A Division of Emerson Process Management Contents iii
Instruction Manual
748214-V
June 2009
Figure 2-1. Power Supply Board Voltage Select Switches .......................................................... 2-2
Figure 2-2. Temperature Control Board ....................................................................................... 2-3
Figure 2-3. Cable Gland .............................................................................................................. 2-3
Figure 2-4. Rear View of Model 951C (cover removed).............................................................. 2-4
Figure 2-5. Rear Panel Wiring Connections ................................................................................ 2-4
Figure 3-1. Model 951C Controls, Indicators and Adjustments................................................... 3-2
Figure 3-2. Signal Board.............................................................................................................. 3-3
Figure 3-3. Signal Board Test Points .......................................................................................... 3-3
Figure 3-6. PPM Range Select Switch ........................................................................................ 3-3
Figure 3-7. Configuration Jumper Settings.................................................................................. 3-3
Figure 3-8. Range 2 Selection Jumpers ...................................................................................... 3-3
Figure 3-9. Power Supply Board ................................................................................................. 3-5
Figure 4-1. Analyzer Block Diagram............................................................................................ 4-4
Figure 4-2. Analyzer Thermal System ......................................................................................... 4-5
Figure 6-1. Major Assemblies of the Model 951C ....................................................................... 6-3
Figure 6-2. Photomultiplier Housing Assembly ............................................................................ 6-4
Figure 6-3. Converter Assembly.................................................................................................. 6-5
Figure 6-4. Case Heater Temperature Control Assembly........................................................... 6-6
Model 951C
LIST OF ILLUSTRATIONS
LIST OF TABLES
Table 3-1. Resistance of Converter Temperature Sensor vs. Temperature .....................................3-7
LIST OF DRAWINGS
Drawing 1-1 Panel Cutout / Installation Drawing
Drawing 1-2 Flow Diagram, Lo/Mid Range
Drawing 1-3 Flow Diagram, Hi Range
iv Contents Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
Rosemount Analytical Inc. A Division of Emerson Process Management Contents v
Instruction Manual
Model 951C
PREFACE
The purpose of this manual is to provide information concerning the components,
functions, installation and maintenance of the 951C NOX Analyzer.
Some sections may describe equipment not used in your configuration. The user should
become thoroughly familiar with the operation of this module before operating it. Read
this instruction manual completely.
DEFINITIONS
The following definitions apply to DANGERS, WARNINGS, CAUTIONS and NOTES found throughout
this publication.
DANGER .
748214-V
June 2009
Highlights the presence of a hazard which will cause severe personal injury, death, or substantial
property damage if the warning is ignored.
WARNING .
Highlights an operation or maintenance procedure, practice, condition, statement, etc. If not
strictly observed, could result in injury, death, or long-term health hazards of personnel.
CAUTION.
Highlights an operation or maintenance procedure, practice, condition, statement, etc. If not
strictly observed, could result in damage to or destruction of equipment, or loss of effectiveness.
NOTE
Highlights an essential operating procedure,
condition or statement.
Rosemount Analytical Inc. A Division of Emerson Process Management Preface P-1
Instruction Manual
748214-V
June 2009
Model 951C
SAFETY SUMMARY
If this equipment is used in a manner not specified in these instructions, protective systems may be
impaired.
AUTHORIZED PERSONNEL
To avoid explosion, loss of life, personal injury and damage to this equipment and on-site
property, all personnel authorized to install, operate and service the this equipment should be
thoroughly familiar with and strictly follow the instructions in this manual. SAVE THESE INSTRUCTIONS.
DANGER.
ELECTRICAL SHOCK HAZARD
Do not operate without doors and covers secure. Servicing requires access to live parts which can
cause death or serious injury. Refer servicing to qualified personnel.
This instrument was shipped from factory set up to operate on 115 volt 50/60 Hz. For operation on
230 volt 50/60 Hz, refer to Section 2-3.
For safety and proper performance this instrument must be connected to a properly grounded
three-wire source of power.
WARNING
INTERNAL ULTRAVIOLET LIGHT HAZARD
Ultraviolet light from the ozone generator can cause permanent eye damage. Do not look directly at
the ultraviolet source in ozone generator. Use of ultraviolet filtering glasses is recommended.
P-2 Preface Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
Model 951C
WARNING
TOXIC CHEMICAL HAZARD
This instrument generates ozone which is toxic by inhalation and is a strong irritant to throat and
lungs. Ozone is also a strong oxidizing agent. Its presence is detected by a characteristic pungent
odor.
The instrument exhaust contains both ozone and nitrogen dioxide, both toxic by inhalation, and
may contain other constituents of the sample gas which may be toxic. Such gases include various
oxides of nitrogen, unburned hydrocarbons, carbon monoxide and other products of combustion
reactions. Carbon monoxide is highly toxic and can cause headache, nausea, loss of
consciousness, and death.
Avoid inhalation of the ozone produced within the analyzer and avoid inhalation of the sample and
exhaust products transported within the analyzer. Avoid inhalation of the combined exhaust
products at the exhaust fitting.
Keep all tube fittings tight to avoid leaks. See Section 2-8 for Leak Test Procedure.
Connect rear exhaust outlet to outside vent by a 1/4 inch (6.3 mm) or larger stainless steel or Teflon
line. Check vent line and connections for leakage.
748214-V
June 2009
WARNING .
PARTS INTEGRITY
Tampering or unauthorized substitution of components may adversely affect safety of this product.
Use only factory documented components for repair.
WARNING.
HIGH PRESSURE GAS CYLINDERS
This instrument requires periodic calibration with a known standard gas. See Sections 2-5 and 3-3.
See also General Precautions for Handling and Storing High Pressure Gas Cylinders, page P-5.
Rosemount Analytical Inc. A Division of Emerson Process Management Preface P-3
Instruction Manual
748214-V
June 2009
WARNING.
TOXIC AND OXIDIZING GAS HAZARD
The ozone generator lamp contains mercury. Lamp breakage could result in mercury exposure.
Mercury is highly toxic if absorbed through skin or ingested, or if vapors are inhaled.
HANDLE LAMP ASSEMBLY WITH EXTREME CARE
If lamp is broken, avoid skin contact and inhalation in the area of the lamp or the mercury spill.
•
Immediately clean up and dispose of the mercury spill and lamp residue as follows:
•
Wearing rubber gloves and goggles, collect all droplets of mercury by means of a suction pump
and aspirator bottle with long capillary tube. Alternatively, a commercially available mercury
spill clean-up kit, such as J. T. Baker product No. 4439-01, is recommended.
•
Carefully sweep any remaining mercury and lamp debris into a dust pan. Carefully transfer all
mercury, lamp residue and debris into a plastic bottle which can be tightly capped. Label and
return to hazardous material reclamation center.
Model 951C
•
Do not place in trash, incinerate or flush down sewer.
•
Cover any fine droplets of mercury in non-accessible crevices with calcium polysulfide and
sulfur dust.
WARNING.
TOPPLING HAZARD
This instrument’s internal pullout chassis is equipped with a safety stop latch located on the left
side of the chassis.
When extracting the chassis, verify that the safety latch is in its proper (counter-clockwise)
orientation.
If access to the rear of the chassis is required, the safety stop may be overridden by lifting the
latch; however, further extraction must be done very carefully to insure the chassis does not fall
out of its enclosure.
If the instrument is located on top of a table or bench near the edge, and the chassis is extracted, it
must be supported to prevent toppling.
Failure to observe these precautions could result in personal injury and/or damage to the product.
P-4 Preface Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
748214-V
Model 951C
June 2009
GENERAL PRECAUTIONS FOR HANDLING AND STORING HIGH
PRESSURE GAS CYLINDERS
Edited from selected paragraphs of the Compressed Gas Association's "Handbook of Compressed
Gases" published in 1981
Compressed Gas Association
1235 Jefferson Davis Highway
Arlington, Virginia 22202
Used by Permission
1. Never drop cylinders or permit them to strike each other violently.
2. Cylinders may be stored in the open, but in such cases, should be protected against extremes of weather
and, to prevent rusting, from the dampness of the ground. Cylinders should be stored in the shade when located in areas where extreme temperatures are prevalent.
3. The valve protection cap should be left on each cylinder until it has been secured against a wall or bench, or
placed in a cylinder stand, and is ready to be used.
4. Avoid dragging, rolling, or sliding cylinders, even for a short distance; they should be moved by using a suitable hand-truck.
5. Never tamper with safety devices in valves or cylinders.
6. Do not store full and empty cylinders together. Serious suckback can occur when an empty cylinder is attached to a pressurized system.
7. No part of cylinder should be subjected to a temperature higher than 125°F (52°C). A flame should never be
permitted to come in contact with any part of a compressed gas cylinder.
8. Do not place cylinders where they may become part of an electric circuit. When electric arc welding, precautions must be taken to prevent striking an arc against the cylinder.
Rosemount Analytical Inc. A Division of Emerson Process Management Preface P-5
Instruction Manual
748214-V
June 2009
Model 951C
DOCUMENTATION
The following 951C instruction materials are available. Contact Customer Service Center or the local representative to order.
748214 Instruction Manual (this document)
P-6 Preface Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
CONDENSED STARTUP AND CALIBRATION PROCEDURE
Instruction Manual
748214-V
June 2009
The following summarized instructions on
startup and calibration are intended for operators already familiar with the analyzer.
For initial startup, refer to detailed instructions
provided in Section 3.
1. Review the Purchase Order from the 951C
Analyzer. Make a note of the Range that
was purchase (Low Range, Mid Range, or
High Range).
2. Set Range switch on the Signal Conditioning
Board to position 4, 250ppm, 500ppm, or
2500 ppm (see Figure 3-2, page 3-2).
3. On the Signal Conditioning Board, Verify that
Hi/Mid/Lo Range Configuration Jumpers are
installed for the Range that was purchase
(Figure 3-7, page 3-3)
4. Apply power to the analyzer. The analyzer
will now require approximately one to two
hours for temperature equilibrium before being ready for calibration.
5. Verify that the pressure regulator on the cylinder of zero gas (nitrogen or air) or sample
gas is set for supply pressure of 10 to 17
psig.
8. Establish correct pressure of zero gas:
a. Supply zero gas to rear panel SAM-
PLE inlet and set to 15 psig.
b. Note reading on SAMPLE Pressure
Gauge. It should be the same as in
Step 6b. If not, adjust output pressure regulator on the zero gas cylinder as required.
7. Establish correct pressure of upscale
standard gas:
a. Supply upscale standard gas to rear
panel SAMPLE inlet.
b. Note reading on SAMPLE Pressure
Gauge. It should be the same as in
Step 7b. If not, adjust output regulator on cylinder of upscale standard
gas as required.
NOTE
Supply pressure for sample, upscale
standard gas and zero air must be the
same. If not, the readout will be in error.
8. Zero Calibration:
6. Verify that the pressure regulator on the cylinder of air (ozonator supply) is set for supply
pressure of 20 to 25 psig.
7. Establish correct pressure of sample gas:
a. Supply sample gas to rear-panel SAM-
PLE inlet at 10 to 17 psig (normally 15
psig).
b. Adjust SAMPLE Back Pressure Regula-
tor so that SAMPLE Pressure Gauge indicates the value appropriate to the
desired operating range (normal operating pressure is 3 to 5 psig). Using the
Mid range setting, set the sample pressure regulator to 2.5 psig See Figure
3-1.
Rosemount Analytical Inc. A Division of Emerson Process Management Preface P-7
a. Set PPM RANGE Switch (Figure
3-6, page 3-3) for range to be used
for sample analysis. Set the front
panel RANGE1 Control at normal
operating setting, if known, or at
about middle or the range if normal
setting is not known.
b. Supply zero gas to rear panel SAM-
PLE inlet.
c. Adjust front panel ZERO Control for
reading of zero on meter or recorder.
9. Upscale Calibration:
a. Set PPM RANGE Switch (Figure
3-6, page 3-3) at setting appropriate
to the particular span gas.
Instruction Manual
748214-V
June 2009
Model 951C
b. Supply upscale standard gas of accu-
rately known NOX content to rear panel
SAMPLE inlet.
c. Adjust front panel RANGE1 Control so
that reading on meter or recorder is
equal to the know parts-per-million concentration of NOX in the span gas.
d. Adjust R25 on the signal board so that
the Display value and the recorder output are equal.
NOTE
It is the responsibility of the user to
measure efficiency of the NO2-to-NO
converter during initial startup, and
thereafter at intervals appropriate to the
application, normally once a month.
P-8 Preface Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
SECTION 1
DESCRIPTION AND SPECIFICATIONS
1-1 OVERVIEW
The Model 951C NOX Analyzer is designed to
measure NOX using one of three sets of ranges
designated as Hi, Mid, or Lo. The Hi Range set
consists of spans with ranges of 0-100, 0-250,
0-1000, and 0-2500 ppm NOX. The Mid Range
set consists of spans with ranges of 0-20, 0-50,
0-200, and 0-500 ppm NOX. The Lo Range set
consists of spans with ranges of 0-10, 0-25,
0-100, and 0-250 ppm NOX.
The NOX analyzer continuously analyzes a flowing gas sample for NOX [nitric oxide (NO) plus
nitrogen dioxide (NO2)]. The sum of the concentrations is continuously reported as NOX.
The analyzer is based on the chemiluminescence method of NO detection. The sample is
continuously passed through a heated bed of
vitreous carbon, in which NO2 is reduced to NO.
Any NO initially present in the sample passes
through the converter unchanged, and any NO
is converted to an approximately equivalent
(95%) amount of NO.
The case heater assembly of the Model
951C maintains the internal temperature at
approximately 50oC (122oF).
1-2 TYPICAL APPLICATIONS
The Model 951C Analyzer has specific applications in the following areas:
• Oxides of nitrogen (NOX)
emissions from the combustion
of fossil fuels in:
• Vehicle engine exhaust
• Incinerators
• Boilers
• Gas appliances
2
• Nitric acid plant emissions
• Turbine exhaust
The NO is quantitatively converted to NO2 by
gas-phase oxidation with molecular ozone produced within the analyzer from air supplied by
an external cylinder. During this reaction, approximately 10% of the NO2 molecules are elevated to an electronically excited state, followed
by immediate decay to the non-excited state,
accompanied by emission of photons. These
photons are detected by a photomultiplier tube,
which in turn generates a DC current proportional to the concentration of NOX in the sample
stream. The current is then amplified and used
to drive a front panel display and to provide potentiometric and isolated current outputs.
To minimize system response time, an internal
sample-bypass feature provides high-velocity
sample flow through the analyzer.
The Backlight blinks when the analyzer is 10%
or more over-range. Selecting a less sensitive
(higher) range restores the display function.
Rosemount Analytical Inc. A Division of Emerson Process Management Installation 1-1
• Ammonia in pollution control
equipment (with converter)
• Nitric oxide emissions from
decaying organic material (i.e.,
landfills).
Instruction Manual
748214-V
June 2009
1-3 SPECIFICATIONS
Ranges
LO.........................................
MID.......................................
HI.........................................
Repeatability.................................. within 0.1 ppm or ±1% of fullscale, whichever is greater
Zero/Span Drift .............................. less than ±0.1 ppm or ±1% of fullscale, whichever is greater, in 24
Response Time
(Electronic + Flow) ..............
Sensitivity ...................................... less than 0.1 ppm or 1% of fullscale, whichever is greater
Detector Operating Pressure......... atmospheric
Total Sample Flow Rate ................ 1 Liter per minute at 20 psig
Sample Pressure ........................... 138 kPa (20 psig)
Ozone Generator Gas ................... U.S.P. breathing-grade air
Ambient Temperature Range ........ 4 to 40°C (40 to 104°F)
Analog Output
Potentiometric...................... 0 to +5 VDC, 2000 ohm minimum load
Isolated Current ................... Field-selectable 0 to 20 or 4 to 20 mA, 700 ohm max load
Display ................................. Digital, 4-1/2 digit LCD, readout in engineering units, back-lighted
Power Requirements ..................... 115/230 VAC ±10%, 50/60 ±3 Hz, 570 W maximum
Enclosure....................................... General purpose for installation in weather-protected areas
Dimensions.................................... 8.7 in. x 19.0 x 19.0 in. (H x W x D)
Weight ........................................... 22.2 kg (49 lbs) approximate
Model 951C
0 to 10, 0 to 25, 0 to 100, 0 to 250 ppm NO
0 to 20, 0 to 50, 0 to 200, 0 to 500 ppm NO
0 to 100, 0 to 250, 0 to 1000, 0 to 2500 ppm NOX
hours at constant temperature
less than ±0.2 ppm or ±2% of fullscale, whichever is greater, over
any 10°C interval from 4 to 40°C (for rate change of 10°C or less
per hour)
90% of fullscale in less than 1 minute
22.0 cm x 48.3 cm x 48.3 cm (H x W x D)
X
X
Description and Specifications Rosemount Analytical Inc. A Division of Emerson Process Management
1-2
Model 951C
Instruction Manual
748214-V
June 2009
SECTION 2
INSTALLATION
2-1 UNPACKING
Carefully examine the shipping carton and contents for signs of damage. Immediately notify
the shipping carrier if the carton or its contents
are damaged. Retain the carton and packing
material until the instrument is operational.
2-2 LOCATION
See drawing 654063 for Outline and Mounting
dimensions.
Install analyzer in a clean area, free from moisture and excessive vibration, at a stable temperature within 4 to 40°C.
The analyzer should be mounted near the sample source to minimize sample-transport time.
A temperature control system maintains the internal temperature of analyzer at 50°C (122°F)
to ensure proper operation over an ambient
temperature range of 4°C to 40°C (40°F to
104°F). Temperatures outside these limits necessitate use of special temperature-controlling
equipment or environmental protection. Also,
the ambient temperature should not change at a
rate exceeding 10°C/hr.
The cylinders of air and span gas should be located in an area of constant ambient temperature (±10°C).
2-3 VOLTAGE REQUIREMENTS
WARNING
ELECTRICAL SHOCK HAZARD
For safety and proper performance this
instrument must be connected to a properly
grounded three-wire source of power.
This instrument was shipped from the factory
set up to operate on 115 VAC, 50/60 Hz electric
power. For operation on 230 VAC, 50/60 Hz, on
the Power Supply Board (Figure 3-9, page 3-5)
position voltage select switches S1, S2, S3
(Figure 2-1, page 2-2) and S3 (located on the
Temperature Control Board (Figure 2-2, page 2-
2) in the 230 VAC position.
Refer to Figure 2-4, page 2-3. On the rear of the
analyzer, remove the 6.25 A fuse (P/N 902413)
and replace with the 3.15 A fuse (P/N 898587)
provided in the shipping kit.
2-4 ELECTRICAL CONNECTIONS
The power and output (recorder and current)
cable glands are supplied loose in the shipping
kit to allow cable installation to connectors or
terminal strips.
Cable Gland Part No.
Power 899330
Recorder 899329
Remove rear cover to access terminals. Route
each cable through the cable gland and connect
to the appropriate connector or terminal strip,
tighten the gland.
a. Line Power Connections
Refer to Figure 2-3 (page 2-3), Figure 2-4
(page 2-3), Figure 2-5 (page 2-4) and drawing 654063. If this instrument is located on
a bench or table top or is installed in a protected rack, panel or cabinet, power may be
connected via a 3-wire flexible power cord,
minimum 18 AWG (max. O.D. 0.480", min.
O./D. 0.270"), through the hole labeled
POWER, utilizing connector gland (P/N
899330) provided.
Route the power cable through the cable
gland and connect the leads to TB1 on the
rear panel. Tighten the cable gland adequately to prevent rotation or slippage of the
power cable. Since the rear terminals do not
slide out with the chassis, no excess power
cable slack is necessary.
Rosemount Analytical Inc. A Division of Emerson Process Management Installation 2-3
Instruction Manual
748214-V
June 2009
Model 951C
The following power cord and/or support
feet (for bench top use) are available:
•
Power Cord 634061
•
North American power cord set
(10 foot)
•
Enclosure Support Kit 634958
•
Enclosure support feet (4)
•
Power Cord/Enclosure Support
Kit 654008
•
North American power cord set
(10 foot)
•
Enclosure support feet (4)
If the instrument is permanently mounted in
an open panel or rack, use electrical metal
tubing or conduit.
Set switch window for voltage required.
Figure 2-1. Power Supply Board Voltage Select Switches
S3
Set switch window for voltage required.
Figure 2-2. Temperature Control Board
2-2 Installation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
RANGE 1
RANGE 2
RANGE 3
RANGE 4
RTN
RTN
+24 VDC IN
+24 VDC IN
GND
GND
INTERIOR EXTERIOR
Instruction Manual
748214-V
June 2009
b. Potentiometric Recorder Connections
Refer to Figure 2-3 (below), Figure 2-5
(page 2-4) and drawing 654063. Potentiometric recorder connections are made on
the rear panel. Route the potentiometric recorder cable through the cable gland in the
hole labeled RECORDER OUTPUT and
connect to VOLT OUTPUT terminals.
Potentiometric recorder cable specifications
are as follows:
•
Distance from recorder to analyzer:
1000 feet (305 meters) maximum
•
Input impedance: Greater than 2000
ohms
•
Cable (user supplied): Two-conductor,
shielded, min. 20 AWG
•
Voltage output: 0 to +5 VDC
c. Current Recorder Connections
Refer to Figure 2-3 (below), Figure 2-5
(page 2-4) and drawing 654063. Current
recorder connections are made on the rear
panel. Route the current recorder cable
through the cable gland in the hole labeled
RECORDER OUTPUT and connect to CUR
OUTPUT terminals
Current recorder interconnection cable
specs are as follows:
•
Distance the recorder from analyzer: 3000 feet (915 meters).maximum
•
Load resistance: Less than 700
Ohms.
•
Cable (user supplied):
Two-conductor, shielded, min. 20
AWG
As supplied by the factory, the current
output produces a zero of 4 mA. The
current output may be adjusted to produce a zero of 0 mA as follows:
1. Zero the instrument as in Section 3-
4. Adjust R23, the zero-adjust potentiometer on the Power Supply
Board, to produce 0 mA current
output.
Nut Gland Nut
Cable
Case Wall
Figure 2-3. Cable Gland
Rosemount Analytical Inc. A Division of Emerson Process Management Installation 2-3
AIR
IN
20 PSI (138 kPa)
NOMINAL
Fuse
EXHAUST
SAMPLE
IN
10 PSI - 17 PSI
(70 kPa - 120 kPa)
RECORDER
OUTPUT
FUSE
CUR
OUTPUT
+ - G + -
Figure 2-4. Rear View of Model 951C (cover removed)
L1/HOT
L2/NEUT
GND
VOLT
OUTPUT
POWER
CHS
See Figure 2-5 for
CHS
connections
Instruction Manual
L1/HOT
L2/NEUT
GND
RANGE 1
RANGE 2
RANGE 3
RANGE 4
RTN
RTN
+24 VDC IN
+24 VDC IN
GND
GND
748214-V
June 2009
RECORDER
OUTPUT
J2
FUSE
CUR
OUTPUT
+ - G + -
TB2
TB2
Current Output Connections
Figure 2-5. Rear Panel Wiring Connections
POWER
CHS
CHS
TB1
VOLT
OUTPUT
TB2
Recorder Connections
Model 951C
J2
Remote Range Change
Connections
TB1
AC Power Connections
2-4 Installation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
2-5 GAS REQUIREMENTS
The instrument requires two gases normally
supplied from cylinders. They are:
a. Air (U.S.P. Breathing Grade)
This is used as both (a) an oxygen source
for generation of the ozone required for the
chemiluminescence reaction, and (b) a
standard gas for zero calibration (nitrogen
can also be used). Gas for each purpose
must be supplied from a separate cylinder
due to different pressure requirements at
ozonator and zero inlets.
b. Span Gas
This is a standard gas of accurately known
composition, used to set an upscale calibration point. The usual span gas is NO or NO2
in a background of nitrogen.
WARNING
HIGH PRESSURE GAS CYLINDERS
This instrument requires periodic calibration
with a known standard gas. See Section 3-3.
See also General Precautions for Handling
and Storing High Pressure Gas Cylinders,
page P-5.
NOTE
For maximum calibration accuracy, the
concentration of NO in the span gas
should be similar to that in the sample
gas. Also, the span gas should be
supplied to the rear panel SAMPLE inlet
at the same pressure as the sample gas.
To ensure constant pressure, a pressure
regulator may be utilized immediately
upstream from the SAMPLE inlet.
Each gas used should be supplied from a
tank or cylinder equipped with a clean,
non-corrosive type, two-stage regulator. In
addition, a shut-off valve is desirable. Install
the gas cylinders in an area of relatively
constant ambient temperature.
2-6 SAMPLE REQUIREMENTS
The sample must be clean and dry before
entering the analyzer. In general, before
admission to the analyzer, the sample
should be filtered to eliminate particles larger than two microns and have a dew point
below 90°F (32°C). The factory can provide
technical assistance if desired.
Proper supply pressure for sample, zero
and span gases for the Model 951C is
20 psig (138 kPa).
2-7 GAS CONNECTIONS
WARNING
TOXIC AND OXIDIZING GAS HAZARDS
This instrument generates ozone which
is toxic by inhalation and is a strong
irritant to throat and lungs. Ozone is
also a strong oxidizing agent. Its
presence is detected by a characteristic
pungent odor.
The instrument exhaust contains both
ozone and nitrogen dioxide, both toxic
by inhalation, and may contain other
constituents of the sample gas which
may be toxic. Such gases include
various oxides of nitrogen, unburned
hydrocarbons, carbon monoxide and
other products of combustion reactions.
Carbon monoxide is highly toxic and can
cause headache, nausea, loss of
consciousness, and death.
Avoid inhalation of the ozone produced
within the analyzer and avoid inhalation
of the sample and exhaust products
transported within the analyzer. Avoid
inhalation of the combined exhaust
products at the exhaust fitting.
Keep all tube fittings tight to avoid leaks.
See Section 2-8 for Leak Test Procedure.
Connect rear exhaust outlet to outside
vent by a 1/4 inch (6.3 mm) or larger
stainless steel or Teflon line. Check vent
line and connections for leakage.
Rosemount Analytical Inc. A Division of Emerson Process Management Installation 2-5
Instruction Manual
748214-V
June 2009
Model 951C
1. Remove plugs and caps from all inlet and
outlet fittings. (See Figure 2-4, page 2-3.)
2. Connect EXHAUST outlet to external vent
via tubing with O.D. of 1/4-inch (6.3 mm) or
larger. Use only stainless steel or Teflon
tubing.
3. Connect external lines from ozonator air
and sample sources to corresponding rear
panel inlet ports. For sample line, stainless
steel tubing is recommended.
4. Adjust regulator on ozonator air cylinder for
output pressure of 20 to 25 psig (138 to 172
kPa). At least 20 psig should be present at
rear of analyzer.
5. Supply sample gas to rear panel SAMPLE
inlet at appropriate pressure: 20 psig (138
kPa). The nominal input pressure is 20 psig
(138 kPa).
2-8 LEAK TEST
The following test is designed for sample
pressure up to 5 psig (35 kPa).
1. Supply air or inert gas such as nitrogen
at 5 psig (35 kPa) to analyzer sample
and air input fittings.
2. Seal off analyzer exhaust fitting with a
tube cap.
3. Use a suitable test liquid such as
SNOOP (P/N 837801) to detect leaks.
Cover all fittings, seals, or possible leak
sources.
4. Check for bubbling or foaming which indicates leakage, and repair as required.
Any leakage must be corrected before
introduction of sample and/or application of electrical power.
For positive assurance that system is leak
free, perform one of the tests in Section 5.0.
2-6 Installation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Converter
SIGNAL BOARD
Ozone Indicator
Lamp
Range1 Control
Zero Control
Display
TP2
Current Output
Current Output
Convertor
PMT
(R30)
Voltage Select
Voltage Select
Voltage Select
CASE HEATER TEMPERAT
URE CONTROL AS SEMBLY
Voltage Select
SAMPLE PRESSURE
SAMPLE PRESSURE
POWER SUPP LY BOARD
Range2 Control
Instruction Manual
748214-V
June 2009
SECTION 3
OPERATION
3-1 FRONT PANEL INDICATORS AND
CONTROLS
a. Display
The display is a 4-digit liquid crystal device which always displays NOX concentration in parts-per-million. Figure 3-1
below.
b. Range Selection
The Model 951C has twelve customer selectable ranges, four LO ranges (10 ppm,
25 ppm, 100 ppm and 250 ppm), four MID
ranges (20 ppm, 50 ppm, 200 ppm and
500 ppm), and four HI ranges (100 ppm,
250 ppm 1000 ppm and 2500 ppm). The
range is selected by positioning the PPM
RANGE Switch (SW1) and the five configuration jumpers on the Signal Board to
the desired range controlling the recorder
output. Refer to Figure 3-2, page 3-2.
The Backlight will blink for values 10% in
excess of the range maximum. Moving
the switch to the right selects a higher
fullscale value and restores the display.
Range Select
Switch (SW1)
0-5VDC Adj.
(R25)
ADC Adj
(R43)
Heater
(R9)
Temp Check
(S4)
Zero (R23)
High Voltage
Span (R20)
(See Figure 3-2)
(Signal Board DS1)
(Signal Board R100)
(Signal Board R102)
(Signal Board R101)
Figure 3-1. Model 951C Controls, Indicators and Adjustments
c. Sample Pressure Gauge
The internal SAMPLE pressure (nominally
4 psig, 28 kPa) is adjusted by rotation of
the Sample Pressure Regulator. See
Figure 3-1 below.
NOTE
Using the MID ranges (20, 50, 200, and
500 ppm), set the sample pressure
regulator to 2.5 psig, 17.5 kPa
d. Ozone Pressure
The OZONE pressure is determined by
the pressure regulator of the air supply
cylinder. A nominal pressure of 20 to 25
psig (138 to 172 kPa) is recommended.
Proper operation is indicated when the
front panel OZONE indicator lamp is lit.
NOTE
If ozone lamp does not light, increase
pressure slightly by adjusting pressure
regulator control on the air cylinder.
(See Figure 3-3)
(See Figure 6-4)
TEMPERATURE CON TROL BOARD (See Figure 2-2)
(S3)
(S3)
(S1)
(S2)
GAUGE
REGULATOR
(Adjustment Knob)
(Signal Board DS2)
Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-1
Instruction Manual
748214-V
June 2009
Model 951C
e. Zero and Span Potentiometers
See Figure 3-1 (page 3-1) and Figure 3-2
below. Screwdriver access holes through
the front panel allow adjustments of the
ZERO, RANGE1 and RANGE2 potentiometers (R100, R101 and R102 on the
Signal Board).
Lo/Mid/Hi Selection Jumpers
(Figure 3-6, page 3-3)
Electrometer
Assembly
\
Range 1 (R101)
f. Ozone Interlock
The ozone-producing UV lamp will not ignite or stay lit unless adequate air pressure is present at the AIR inlet (see
Figure 2-4, page 2-3). Nominal setpoint
pressure is 20 to 25 psig.
R25 R43
Range 2 (R102)
Figure 3-2. Signal Board
Figure 3-3. Signal Board Test Points
PPM Range Select Switch
(Figure 3-6, page 3-3)
Zero (R100)
3-2 Operation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
3-2 STARTUP PROCEDURE
The following are detailed instructions on
startup and calibration.
1. Supply electrical power to the analyzer.
The analyzer will require approximately
two hours for temperature equilibration before calibration.
2. On Signal Board, Figure 3-2, page 3-2:
a. Using a small flat screwdriver, set
PPM RANGE Switch (Figure 3-6
below) to the range that will be used
for sample analysis.
Range
(S1 Pos)
1 10 20 100
2 25 50 250
3 100 200 1000
4 250 500 2500
Other Remote Remote Remote
ppm Fullscale
Lo
Range
Mid
Range
Hi
Range
c. Set Range2 Selection jumpers to
Range 4, 2500ppm as shown in
Figure 3-8 below.
Range
Position
JP1 10 20 100
JP2 25 50 250
JP3 100 200 1000
JP4 250 500 2500
Figure 3-8. Range 2 Selection Jumpers
PPM Range
Figure 3-6. PPM Range Select Switch
b. Set Configuration Jumper Settings to
desired position as shown in Figure
3-7 below.
Figure 3-7. Configuration Jumper Settings
Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-3
Instruction Manual
748214-V
June 2009
Model 951C
3. Establish correct pressure for air by the following:
a. Adjust OZONE Pressure Regulator so
that OZONE Pressure Gauge indicates 20 to 25 psig (138 to 172 kPa).
b. To establish correct pressure of zero gas,
supply zero gas to rear panel SAMPLE
inlet. Note reading on internal SAMPLE
Pressure Gauge. It should be the same
as the nominal 4 psig (28 kPa) for the Lo
and Hi Ranges and 2.5 psig for the Mid
Range SAMPLE pressure indicated on
the internal SAMPLE pressure gauge.
This should remain constant when the
analyzer input SAMPLE is switched from
calibration gas standard to a zero gas
standard. This may be assured by setting
the delivery from the SAMPLE and the
zero gas cylinder of span gas cylinder to
the same value of delivery pressure,
nominally 20 psig (138 kPa). If not, adjust output pressure regulator on zero gas
cylinder as required.
4. Establish correct pressure of sample gas
by the following:
a. Supply sample gas to rear panel
SAMPLE inlet.
b. Adjust SAMPLE Backpressure Regula-
tor so internal SAMPLE Pressure
Gauge indicates the value appropriate
to the desired operating range.
NOTE
Inability to obtain a flow of one liter per
minute at the EXHAUST outlet usually
indicates insufficient sample supply
pressure at the SAMPLE inlet. Use a
2400 cc flowmeter (i.e., Brooks P/N
1350) at the EXHAUST outlet to
measure flow.
5. Establish correct flow of upscale standard
gas by the following:
a. Supply upscale standard gas to rear
panel SAMPLE inlet.
b. Note reading on internal SAMPLE
Pressure Gauge. It should be the
same as in Step 3b.
NOTE
Supply pressures for sample and
upscale standard gases must be the
same. Otherwise, readout will be in
error.
The analyzer is now ready for calibration.
3-4 Operation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
Figure 3-9. Power Supply Board
Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-5
Instruction Manual
748214-V
June 2009
Model 951C
3-3 CALIBRATION
a. Zero Calibration
1. On the Signal Board (Figure 3-2,
page 3-2), set PPM RANGE Switch
(Figure 3-6, page 3-3) for the same
range that will be used during sample
analysis. Set front panel RANGE1
Control at about mid-range.
2. Supply zero gas to rear panel SAMPLE inlet.
3. Using the MID Range set the sample
pressure regulator to 2.5 psig. Using
the Lo or Hi ranges, set the sample
pressure to 4.0 psig
4. After a stable reading is reached, adjust the zero by inserting a screwdriver in the ZERO slot on the front
panel of the analyzer and turning until
zero reading is obtained.
b. Upscale Calibration
5. If necessary, increase sensitivity by
raising photomultiplier voltage. Adjust
R30 on the Power Supply Board
(Figure 3-9) clockwise to increase
(negative) the photomultiplier high
voltage and sensitivity. This will interact with zero. Repeat Zero Calibration and Upscale Calibration (through
step 3).
6. If necessary increase the upscale
readings on the LCD display by adjusting potentiometer R43 until the
display shows the correct span gas
readings. Now, adjust R 25 so that
reading on display and the recorder is
equal to the known parts-per-million
concentration of NOX in the span gas.
3-4 ROUTINE OPERATION
After calibrating analyzer per Section 3-3,
supply sample to SAMPLE inlet. Set PPM
RANGE Switch (Figure 3-6, page 3-3) in appropriate position. The instrument will now
continuously analyze the sample stream.
1. On the Signal Board (Figure 3-2,
page 3-2) set Upscale Calibration
PPM RANGE Switch (Figure 3-6,
page 3-3) to the position appropriate
to the particular span gas.
2. Supply upscale standard gas of accurately known NOX content to rear
panel SAMPLE inlet.
3. Using the MID Range set the sample
pressure regulator to 2.5 psig. Using
the Lo or Hi ranges, set the sample
pressure to 4.0 psig
4. Adjust front panel RANGE1 Control
so that reading on display or recorder
is equal to the known parts-per-million
concentration of NOX in the span gas.
If the correct reading is not initially attainable by adjustment of the front
panel RANGE1 Control, make the
electronic adjustment in Step 5.
The Model 951C is designed for continuous
operation. Normally, it is never turned off except for servicing or for a prolonged shutdown.
NOTE
During periods of shutdown, turn off the
ozone lamp by shutting off the input air
source.
3-5 CONVERTER TEMPERATURE
ADJUSTMENT PROCEDURE
Once the appropriate high voltage and electronic gain have been selected such that the
named calibration gas value is indicated by
the Model 951C, the instrument is ready for
adjustment of the converter temperature.
The vitreous carbon converter used in this
analyzer has a low surface area which gradually increases during high temperature operation of the converter material.
3-6 Operation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
Initially, the temperature of the peak of the
converter efficiency starts at a relatively high
value because significant heat must be supplied to make the converter active enough to
reduce the input nitrogen dioxide to nitric oxide at the required 95% level. During the operation of the analyzer, the temperature of the
peak will fall as the surface area of the converter is increased and less external energy is
required to cause adequate conversion.
In extreme cases, where converter re-profiling
has not been conducted, the converter is so
active that it not only reduces nitrogen dioxide
to nitric oxide, but it reduces the nitric oxide
produced to nitrogen, which is not detected by
the chemiluminescence reaction. The remedy
in this case is to adjust the converter temperature to a lower value to improve the converter
efficiency.
It is important that the converter temperature
be periodically profiled to assure that it is running at its peak efficiency. An interval of one
week is recommended. The nominal range of
operational temperatures for the converter is
275°C to 400°C (527°F to 750°F). The operating temperature of the converter may be conveniently checked on the Power Supply Board
(Figure 3-9, page 3-5) by momentarily depressing switch CONV TEMP CHECK (S4)
while monitoring the resistance across terminals TP1 and TP2.
Table 3-1 allows for conversion of the observed resistance to the operating temperature for the converter.
Follow this procedure to optimize the operating temperature of the converter:
1. Power instrument and allow it to stabilize
at operating temperature (one to two
hours). Measure the operating temperature of the converter by the technique described above. Note the value for future
reference.
2. Admit a calibration gas of known (NO2)
concentration into the analyzer and note
the concentration value determined when
the full response has been achieved.
3. Refer to Power Supply Board Figure 3-9,
page 3-5. Turn the converter temperature
adjust potentiometer (R9 CONV HTR)
one turn counterclockwise from the setting established at the factory, and allow
fifteen minutes for operation at the new
lower temperature setpoint. Recheck the
response and note the value for later use.
4. Increase the temperature of the converter
by rotating the converter temperature adjust potentiometer (R9 CONV HTR) one
quarter turn clockwise, wait fifteen minutes for thermal equilibrium and then remeasure the NO2 calibration gas value.
Note its value. Repeat this procedure of
one quarter turn adjustments of the potentiometer, waiting for thermal stability and
determination of the calibration gas value
until either a 95% value is obtained or the
final one quarter turn adjustment gives an
efficiency increase of less than one percent.
5. Decrease the temperature of converter
operation by rotating the converter temperature adjust potentiometer (R9 CONV
HTR) one eighth of a turn counterclockwise. This places the converter at a temperature suitable for low ammonia
interference and efficient NO2 conversion.
Re-measure the indicated converter temperature and compare it to the initially recorded value.
TEMPERATURE
(°°°°C)
0 400
25 438
100 552
200 704
250 780
300 856
350 932
400 1008
450 1084
Table 3-1. Resistance of Converter Temperature
Sensor vs. Temperature
RESISTANCE
(Ohms)
Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-7
Instruction Manual
748214-V
June 2009
NOTE
Converter temperature is not a direct
measure of converter efficiency.
Temperature measurement is for reference
purposes only.
Model 951C
3-8 Operation Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
3-6 MEASUREMENT OF CONVERTER
EFFICIENCY
It is the responsibility of the user to measure
efficiency of the NO2-to-NO converter during
initial startup, and thereafter at intervals appropriate to the application (normally once a
month).
Section 3-5 optimizes the operating temperature of the converter. It also serves as an efficiency check if the concentration of NO2 in the
calibration gas is documented accurate relative to National Institute of Standards and
Technology (NIST) Reference Materials. If the
concentration of the nitrogen dioxide calibration gas is not known accurately, this procedure still serves to adequately provide the
correct converter operating temperature.
If the only available known standard is the nitric oxide calibration standard, the following
procedure may be performed. This procedure
checks converter efficiency through the utilization of gas-phase oxidation of nitric oxide into
nitrogen dioxide over a range of nitrogen dioxide concentrations. This technique is abstracted and adapted from 40 CFR, Pt. 60,
App. A, Method 20, Paragraph 5.6.
consume nitrogen dioxide as it delivers
sample to the analyzer. Losses of nitrogen dioxide in the pump will be reported
as converter inefficiency.
4. Operate the analyzer and continue to
sample the diluted nitric oxide sample for
a period of at least thirty minutes. If the nitrogen dioxide to nitric oxide conversion is
at the 100% level, the instrument response will be stable at the highest value
noted.
5. If the response at the end of the thirty minute period decreases more than 2.0 percent of the highest peak value observed,
the system is not acceptable and corrections must be made before repeating the
check. If it is determined that observed
subnormal conversion efficiencies are
real, and not due to errors introduced by
nitrogen dioxide consumption in the sample pump or other parts of the sample
handling system, verify that the converter
is peaked at the optimum temperature before replacing with a new converter.
3-7 RECOMMENDED CALIBRATION
FREQUENCY
1. Select the appropriate instrument range.
2. Admit a nitric oxide in nitrogen NIST
traceable calibration gas of a value between 45% and 55% of the instrument
range selected to a clean, evacuated,
leak tight Tedlar bag. Dilute this gas approximately 1:1 with a 20.9% oxygen, purified air.
3. Immediately attach the bag outlet to the
input of the pump supplying pressurized
gas to the analyzer. It is important to use
a sample delivery pump which does not
After initial startup or startup following a shutdown, the analyzer requires about two hours
for stabilization before it is ready for calibration. Maximum permissible interval between
calibrations depends on the analytical accuracy required, and therefore cannot be specified. It is recommended that initially the
instrument be calibrated at least once every 8
hours. This practice should continue until experience indicates that some other interval is
more appropriate.
Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-9
Model 951C
UV
4-1 NITRIC OXIDE DETERMINATION BY
CHEMILUMINESCENCE METHOD
The chemiluminescence method for detection of
nitric oxide (NO) is based on its reaction with
ozone (O3) to produce nitrogen dioxide (NO2)
and oxygen (O2). Some of the NO2 molecules
thus produced are initially in an electronically
excited state (NO2*). These revert immediately
to the ground state, with emission of photons
(essentially red light).
The reactions involved are:
NO + O3 → NO2* + O2
NO2* → NO2 + Red Light
As NO and O3 mix in the reaction chamber, the
intensity of the emitted red light is proportional
to the concentration of NO.
(Any NO2 initially present in the sample is reduced to NO by a heated bed of vitreous carbon
through which the sample is passed before being routed to the reaction chamber.)
The intensity of the emitted red light is measured by a photomultiplier tube (PMT), which
produces a current of approximately 3 X 10-9
amperes per part-per-million of NO in the reaction chamber.
4-2 ANALYZER FLOW SYSTEM
The analyzer flow system is shown in drawing
2-0 and 3-0. Its basic function is to deliver regulated flows of sample, calibration gas, or zero
gas and ozonized air to the reaction chamber.
The discharge from the reaction chamber flows
from the analyzer via the EXHAUST outlet.
a. Flow of Sample, Standard Gas or Zero
Gas to Reaction Chamber
SECTION 4
THEORY
Instruction Manual
748214-V
June 2009
The flow rate of the selected gas into
the reaction chamber is controlled by a
back pressure regulator inside the analyzer. It provides an adjustable, controlled pressure on the upstream side,
where gas is supplied to the calibrated,
flow-limiting sample capillary. The regulator is adjusted for appropriate reading
on the internal SAMPLE Pressure
Gauge. For operation at NO and NO2
levels below 250 ppm, correct setting
on the SAMPLE Pressure Gauge is 4
psig (28 kPa). This results in a flow of
approximately 60 to 80 cc/min to the reaction chamber.
Excess sample is discharged with the
effluent from the reaction chamber via
the EXHAUST outlet. Bypass flow is set
by the restrictor at 1 L/min (nominal) to
ensure proper functioning of the SAMPLE Pressure Regulator and rapid system response. Excessive changes, on
the order of 5 psig (35 kPa), in the
pressure of the sample or standard gas
will affect the bypass flow rate and can
affect accuracy.
b. Ozone Generation
Suitably pressurized air from an external cylinder is supplied to the rear panel
AIR inlet. The proper pressure setting is
20 to 25 psig (138 to 172 kPa). Within
the ozone generator, a portion of the
oxygen in the air is converted to ozone
by exposure to an ultraviolet lamp. The
reaction is:
3O2 → 2O3
From the generator, the ozonized air
flows into the reaction chamber for use
in the chemiluminescence reaction.
Suitably pressurized sample, standard gas
or zero gas is supplied to the rear panel
SAMPLE inlet.
Rosemount Analytical Inc. A Division of Emerson Process Management Theory 4-1
Instruction Manual
748214-V
June 2009
Model 951C
4-3 SIGNAL CONDITIONING AND DISPLAY
A block diagram of the signal-processing electronics is shown in Figure 4-1, page 4-3.
The signal conditioning and display board provides the following functions:
• Signal conditioning circuit consisting of U14
• An analog to digital converter U15.
• Display device U15
• Range Control circuits U9 and U12
• Post signal amplifier and output
amplifier circuit U5
• Display/Backlight blink control U5
and U6
• Range conditions.
• Remote Control Circuits
All of the above functions are on a single board
located at the front of the instrument. Certain
control requirements (ie) range calibration and
zero offset adjustment are available as screwdriver adjustments via the front panel. A digital
liquid crystal display is mounted on the rear side
of the board for data display purposes as are
control potentiometers.
a. Circuit Functions
Signal conditioning amplifiers
Boards assembly 6A00326G01/02 is a high
input impedance electrometer amplifier
board.
Current output from the detector unit is converted to voltage by the electrometer amplifier and then further amplified by post
amplifier.
The electrometer amplifier gain may be reduced by a factor of 10 by shorting JP1 and
by shorting pins 1 and 2 on P1 with the in-
cluded jumpers, this is used for higher
range selection (ie) 100 to 2500 ppm
NOx.
Gain Amplifier U14
The precision amplifier U14 allows 2 selectable gains, on for 10, 100, and 1000
spans and the other for 25, 250, and
2500 spans.
Intermediate gain ranges as required by
the 951C Lo Range: 10, 25, 100, 250
ppm NOx, Mid Range: 20, 50, 200, 500
ppm NOx or Hi Range 100, 250, 1000,
2500 ppm NOx are obtained by interpolating between the requisite ranges using Boolean Logic and Analog
Switches.
Range 1 and Range 2 selection
The signal output of U14 is adjusted at
the front panel for instrument calibration
purposes. Any second range may be
chosen by placing a jumper on JP1,
JP2, JP3, or JP4. When the programmed range is selected, the K2 relay toggles and allowing that range to
be calibrated. Note! If no jumper is present only range 1 may be calibrated
Post Amplifiers U5
The conditioned signal from U14 and
the range calibration potentiometers
R101 and R102 are provided to U5.
This amplifier has switch controlled feed
back resistors that permit gain selections of any range, as determined by
the range switch and associated logic.
An Adjustment potentiometer R25 allows a small correction for inter range
calibration purposes.
The output of U14 is provided to the
Analog to Digital converter for digitization and display purposes. Potentiometer R43 allows adjustment of the signal
to the ADC allowing concordance of display and recorder signals if required.
Normally the ADC should be correctly
calibrated during the factory test procedure and should not require further adjustment. Potentiometer R25 allows
4-2 Theory Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
recorder output adjustment to match display.
U5 is the recorder output amplifier. The output signal may be trimmed by R25 to precisely match the recorder calibration. Note
that this adjustment does not affect or
change the instrument display,
Analog to Digital Converter
U15 is a special integrated circuit with a
built in ADC and LCD Drivers. The signal
data is digitized and provided in the correct
format to the liquid crystal display (LCD).
Display/Backlight and over range blink
Circuits
The display circuits comprise of U15, no adjustments are required for these functions
The blink or over range display function
uses U5, U6, and U9.
U5 is an analog comparator that senses an
over range condition and turns on U6. U6
sets the blink rate for the Backlight.
Remote Control Circuits
The Model 951C is provided with a fully isolated remote control interface. Optical isolators and a remote 24V power supply ensure
that no direct return path exists between the
users system and the 951C When in the
remote mode of operation.
Connecting any input terminal 1 thru 4
to ground terminals 9 or10 will select
one of the four ranges.
For remote operation a 24V power supply should be connected to terminals
5,6 and 7,8, negative or low side is
connected to 5, 6. Positive or high side
to 7,8. For protection purposes the high
side is fused. Note! The local range
switch SW1 must be in the fifth position (position Five) to disconnect local control and provide the return for
remote control.
For local operation Set the range switch
SW1 between setting 1 thru 4. An external 24V supply is not required. SW1
is located on the top of the signal board.
4-4 ANALYZER THERMAL SYSTEM
The Analyzer Thermal System is shown in
Figure 4-2, page 4-3. Its basic function is to
provide a stable thermal environment for the
PMT.
The temperature of the PMT must be held
within a half-degree band at approximately
18°C if it is to produce a useful signal for
low concentrations of NOX. This is accomplished by means of a solid-state cooler
which houses the PMT. The heat which is
radiated from the cooler is carried away by
the Cooler Fan.
Relay K1 switches between the internal
range switch control (SW1) and the External
Remote Range Control. When SW1 is on
setting 5 it causes K1 to toggle and a fully
isolated system is achieved.
Optical Isolators U7, U8, U10, and U13 connects via a ribbon cable to the remote connector panel at the rear of the 951C. A ten
terminal barrier strip provides connection for
remote range selection.
The solid-state cooler must work against a
relatively constant load in order to maintain
the temperature of the PMT. This load is
produced by a case heater and exhaust fan
which control the temperature inside the
case within a one-degree band (approximately 50°C for ambient temperatures from
4°C to 40°C).
The electronics which support the Analyzer
Thermal System and the NO2-to-NO Converter are contained on the Power Supply
Board.
Rosemount Analytical Inc. A Division of Emerson Process Management Theory 4-3
Model 951C
Photomultiplier
Tube
High Voltage
Supply
PMT
Electrometer
Zero Control
Signal/Control Board
Gain
Amplifier
Span
Adjustments
R101, R102
Range Switch
Voltage Output
Control
Power Supply Board
Voltage-to-Current
Converter
Figure 4-1. Analyzer Block Diagram
Display
Instruction Manual
748214-V
June 2009
Span
Amplifier
Potentiometric
Output
Isolated
Current
Output
Rosemount Analytical Inc. A Division of Emerson Process Management Theory 4-5
Instruction Manual
Cooler Fan
PMT
EXHAUST FAN
Top View of Analyzer
748214-V
June 2009
Model 951C
INLET VENT HOLES
SOLID-STATE COOLER
Cooling Fins
CASE HEATER
Fan Heater
FRONT PANEL
Figure 4-2. Analyzer Thermal System
4-6 Theory Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
Rosemount Analytical Inc. A Division of Emerson Process Management Theory 4-7
Model 951C
WARNING
ELECTRICAL SHOCK HAZARD
Servicing requires access to live parts
which can cause death or serious injury.
Refer servicing to qualified personnel.
WARNING
INTERNAL ULTRAVIOLET LIGHT HAZARD
Instruction Manual
748214-V
June 2009
SECTION 5
ROUTINE SERVICING
a. Display Fullscale Span Adjustment
If a recorder is used, and has been properly zeroed, it should agree with the display reading. If not, obtain agreement by
adjustment of R25 on the Signal Board
(see Figure 3-1 (page 3-1) and Figure 3-2
(page 3-2). If agreement cannot be
reached, check the recorder. If the recorder is functioning properly, replace the
Signal Conditioning Board.
Ultraviolet light from the ozone generator
can cause permanent eye damage. Do not
look directly at the ultraviolet source in
ozone generator. Use of ultraviolet
filtering glasses is recommended.
NOTE
The photomultiplier tube must not be exposed to
ambient light. If the photomultiplier tube is exposed to light while the power is on, either
through a loose fitting on the reaction chamber
or any other leak, it will be destroyed. If exposed
to ambient light with the power off, the tube will
be noisy for some period of time. Unless appropriate precautions are observed, light can strike
the tube upon removal of fittings from the reaction chamber.
5-1 SYSTEM CHECKS AND ADJUSTMENTS
The following procedures may be used to determine the cause of unsatisfactory instrument
performance, or to make adjustments following replacement of components. If a recorder
is available, use it for convenience and maximum accuracy in the various tests.
b. Overall Sensitivity
Principal factors that determine overall
sensitivity of the analyzer are the following: (a) sample flow rate to the reaction
chamber, (b) sensitivity of the photomultiplier tube (PMT), and (c) PMT high voltage. If specified fullscale readings are
unobtainable by adjustment of the SPAN
Control, sensitivity is subnormal. The
cause of reduced sensitivity may be in either the flow system (See Section 5-2,
page 5-3) or the electronic circuitry (See
Section 5-6, page 5-10).
If either the High Voltage Board or the
Phototube/Reaction Chamber Assembly
has been replaced, a readjustment of the
high voltage will probably be required to
obtain the correct overall sensitivity. Adjust R30 on the Power Supply Board (see
Figure 3-1 page 3-1 and Figure 3-9 page
3-5) clockwise to increase (negative) the
photomultiplier high voltage and sensitivity, or counterclockwise to decrease
(negative) the voltage and sensitivity.
The adjustment range is about -650 V to
-2100 V for the regulated DC voltage applied to the photomultiplier tube. Nominal
setting is -1100 volts. However, the voltage should be adjusted as required for
overall system sensitivity.
Rosemount Analytical Inc. A Division of Emerson Process Management Troubleshooting 5-1
Instruction Manual
748214-V
June 2009
Model 951C
c. Ozone Output
WARNING
TOXIC GAS HAZARD
Use extreme caution in troubleshooting
the ozone generator. Ozone is toxic.
To check for adequate output from the
ozone lamp, a convenient technique is to
calibrate the analyzer on a high level NO
standard such as 250 ppm NO at the
nominal 4.0 psi internal sample pressure
setpoint, and note the reading. The sample pressure setpoint is then sequentially
set to pressures of 3.0, 2.0, and 1.0 psi
after a stable span gas reading has obtained at the higher pressure setpoint.
The span gas value will change as the
pressure is changed. The difference in
span gas value between two successive
sample pressure levels should be approximately the same for the 4.0 to 3.0,
3.0 to 2.0, and 2.0 to 1.0 pressure steps.
If the size of the span gas value difference increases as the sample pressure is
lowered, the analyzer output is limited by
the amount of ozone production from the
lamp and the two additional checks
should be made. First, verify that the
sample flow (not including bypass) does
not exceed the nominal 60 to 80 cc/min,
at 4.0 psi internal sample pressure. Second, substitute another lamp to see if the
ozone output is increased.
If no other ozone lamp is available, the
analyzer sample input pressure may be
reduced to the pressure where the ozone
limitation is not present. If the lamp output
is low and the sample pressure is reduced
to restore operation to the condition
where ozone limitation is not occurring,
some degradation in analyzer response
time characteristics may occur.
display reading with adjustment of the
ZERO Control. If this cannot be accomplished, the cause must be found and corrected. The fault may be in either the
electronic circuitry or the sample flow system.
First, establish proper performance of the
electronic circuitry. Turn on analyzer
power. Verify that ZERO Control and amplifier are functioning properly. Then,
check for excessive photomultiplier dark
current and/or contamination of the reaction chamber or sample flow system as
follows:
•
Excessive Photomultiplier Dark Current
To check, shut off all flow to the
ozone generator. Turn off ozone
generator. Supply cylinder air to rear
panel SAMPLE inlet. Note response
on display or recorder. If background is still excessive, possible
causes are:
leakage of ambient light to photomultiplier tube
defective photomultiplier tube
electrical leakage in socket assembly
•
Contamination of Reaction Chamber
or Sample Flow System.
See Section 5-4a, page 5-7.
5-2 SERVICING FLOW SYSTEM
To facilitate servicing and testing, the Model
951C has front drawer access.
Drawing 654090 shows flow system details,
including fittings, thread specifications and
connecting tubing.
d. Background Current
With zero air supplied to rear panel SAMPLE inlet, excessive background current
is evidenced by the inability to obtain zero
5-2 Routine Servicing Rosemount Analytical Inc. A Division of Emerson Process Management
a. Cleaning Sample Capillary
If clogging of sample capillary is suspected, measure flow rate as described
below.
Model 951C
Instruction Manual
748214-V
June 2009
1. Turn off instrument power and shut off
all gases.
2. Refer to Figure 6-1 (page 6-4) and
Figure 6-2 (page 6-5). Cover and
shade the fittings on the reaction
chamber with a dark cloth or other
light-shielding material. Remove the
fitting associated with the sample capillary and place a cap over the open
fitting to prevent entry of stray light.
NOTE
If the opened fitting is inadvertently
exposed to ambient light, the
instrument will temporarily give a
highly noisy background reading. If so,
this condition may be corrected by
leaving the instrument on, with high
voltage on, for several hours. If high
voltage is on during exposure, the
photomultiplier tube will be destroyed.
3. With instrument power off, supply
suitable test gas (dry nitrogen or air)
to rear-panel SAMPLE inlet.
4. Connect a flowmeter to open end of
sample capillary. Adjust internal
SAMPLE Pressure Regulator to normal operating setting of 4 psig (28
kPa). Verify that flowmeter indicates
appropriate flow of 60 to 80 cc/min.
NOTE
Do not over-tighten capillary internal
fitting, as over-tightened fittings may
restrict the sample flow.
b. Ozone Restrictor Fitting
With instrument power off, supply suitable
test gas (dry nitrogen or air) to rear panel
AIR inlet. Cover photomultiplier housing
with a dark cloth. At the fittings on the reaction chamber, disconnect the ozone
tube and place a cap over the open fitting
to prevent entry of ambient light. Connect
a flowmeter to open end of ozone tube.
Adjust the OZONE Pressure Regulator so
that the OZONE Pressure Gauge indicates normal operating pressure of 20 to
25 psig (138 to 172 kPa). Verify that test
flowmeter indicates an appropriate flow of
500 to 600 cc/min for 20 psig.
Subnormal flow indicates clogging in the
flow path that supplies air to the ozone
generator. This path contains a Restrictor
(P/N 655519), consisting of a metal fitting
with internal fritted (metal membrane) restrictor to reduce pressure. The fitting is
upstream from the inlet port of the ozone
generator. If the internal restrictor becomes plugged, the assembly (P/N
655519) must be replaced as it cannot
normally be cleaned satisfactorily.
5. If flow is correct, restore analyzer to
normal operation.
6. If flow is low, the capillary requires
cleaning or replacement (Proceed
with the step 7 below).
7. Clean capillary with denatured alcohol, and purge with dry nitrogen or air
for one minute. Reconnect capillary.
8. With the photomultiplier still covered,
slowly insert the free end of the capillary into the corresponding fitting on
the reaction chamber. Push the capillary in until it touches bottom against
the internal fitting. Then tighten fitting
1/4 turn past finger tight.
Rosemount Analytical Inc. A Division of Emerson Process Management Routine Servicing 5-3
5-3 PHOTOMULTIPLIER TUBE/REACTION
CHAMBER
This assembly consists of the photomultiplier
tube and socket, the thermoelectric cooler,
and the reaction chamber. Refer to Figure 6-1
(page 6-4) for location and details of mounting. Refer to Figure 6-2 (page 6-5) for information on the assembly.
The assembly must be removed from the analyzer in order to clean the reaction chamber or
to replace the photomultiplier tube.
Instruction Manual
748214-V
June 2009
Model 951C
a. Removal
To remove the photomultiplier
tube/reaction chamber assembly from the
analyzer, do the follow:
1. Disconnect power from the analyzer.
2. Release pressure from SAMPLE and
AIR supplies.
3. Unplug the electrical cable from the
Power Supply PC Board.
4. Disconnect the high-voltage cable
and the signal cable from the left side
of the assembly. Note the two mounting screws just below the connectors.
5. Uncouple the sample and ozone capillaries and the exhaust line from the
right side of the assembly. Note the
two mounting screws just below the
fittings.
6. Loosen the screws described in steps
4 and 5 above.
7. Lift the assembly from the analyzer.
8. Replace the assembly by reversing
the order of steps 1 through 7 above.
b. Cleaning Reaction Chamber
NOTE:
Photomultiplier tube will be
permanently damaged if exposed to
ambient light while powered with high
voltage. Photomultiplier tube will
develop temporary electronic noise if
exposed to ambient light with high
voltage OFF. A temporary noisy
condition may be corrected by leaving
instrument on, with high voltage on,
for several hours. The required
recovery time depends on intensity
and duration of the previous exposure.
Noise level on the most sensitive
range usually drops to normal within
24 hours.
If sample gas is properly filtered, the reaction chamber should not require frequent
cleaning. In event of carryover or contamination, however, the chamber should
be disassembled to permit cleaning the
quartz window and the optical filter. The
following procedure is recommended.
1. Cover and shade the Reaction
Chamber/Photomultiplier Assembly
with a dark cloth or other
light-shielding material.
NOTE
Always wear surgical rubber gloves
when handling the reaction chamber to
prevent contamination from handling.
2. Note the orientation of the fittings.
Slowly rotate and withdraw the reaction chamber from the housing. Ensure that no light strikes the
photomultiplier tube.
3. Unscrew plastic end cap, thus freeing
the quartz window and the red plastic
optical filter. Note the sequence in
which these are assembled.
4. Clean the reaction chamber by the
appropriate one of the following two
methods, standard or alternate. The
standard method is applicable in most
cases. The alternate method is applicable when the instrument has shown
high residual fluorescence. That condition is indicated by high residual
currents on a zero gas and high differentials between zero gas readings
obtained with the ozone lamp on and
off.
Standard Cleaning Procedure
Using a stiff plastic bristle brush, such as
a toothbrush, scrub the Teflon surface
and gas ports of the reaction chamber
with clean distilled water and Alconox* detergent (P/N 634929). Alconox detergent
is included in the shipping kit provided
with the Model 951C NOX Analyzer, and
is available from Sargent-Welch Scientific
5-4 Routine Servicing Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
Company under its catalog number
S-195650-A.
Using Alconox and clean, soft facial tissue
(NOT industrial wipes), carefully clean the
quartz window. Vigorously flush reaction
chamber and quartz window with clean
distilled water. Blow out all possible water
from internal passages of reaction chamber. Dry reaction chamber and quartz
window in a warm oven at 125°F to 150°F
(52°C to 66°C) for 30 to 45 minutes or
purge-dry the parts with dry cylinder air or
nitrogen to eliminate all moisture.
WARNING
ACID HAZARD
Hydrochloric acid (HC1) is a strong acid. It
is irritating to the skin, mucous
membranes, eyes and respiratory tract.
Direct contact causes severe chemical
burns.
Avoid Contact with eyes and skin and
avoid breathing fumes. Use in hood or well
ventilated place. Wear goggles, rubber
gloves and protective clothing.
Alternate Cleaning Procedure - For
High Residual Fluorescence
Holding the reaction chamber by the tube
fittings, and using appropriate caution,
immerse the white Teflon part of the
chamber in 50% concentrated Reagent
Grade hydrochloric acid. After five minutes, rinse thoroughly with de-ionized water, then air dry as in the standard
cleaning method above.
Place parts in position and press on
end-cap so that mating threads engage
properly, without cross threading. Turn
mating parts in one continuous motion until the parts mesh. Do not over-torque.
With reaction chamber now assembled,
replace and reconnect it in reversed removal sequence. Orient as noted in step
2.
c. Photomultiplier Tube and Housing
The photomultiplier tube operates at high
DC voltages (nominal setting is -1100
volts) and generates small currents that
are highly amplified by the signal-conditioning circuitry. It is therefore
important that ambient humidity and condensed water vapor be excluded from the
interior of the photomultiplier housing.
Ambient humidity can result in electrical
leakage, observed as abnormally high
dark current. Water vapor or condensed
moisture in contact with the photomultiplier tube may result in an abnormally
high noise level during instrument readout
on zero air or upscale standard gas.
The Photomultiplier Tube/Reaction
Chamber Assembly incorporates several
features for exclusion of humidity and
moisture. The photomultiplier socket assembly is potted with high impedance silicone rubber compound and is sealed
from external influences with epoxy and
rubber gasket material. The socket assembly and the reaction chamber are
sealed with O-rings into opposite ends of
the tubular photomultiplier housing. The
socket end of the housing may be sealed
with either one or two O-rings, depending
on the length of the phototube.
d. Replacement of Photomultiplier Tube
The photomultiplier tube assembly must
be removed from the housing in order to
replace the tube. To remove, do the following:
1. Note the orientation of the connectors.
2. Slowly rotate and withdraw the socket
assembly from the housing. Note the
orientation and placement of the
metal shield and the black plastic insulating cover.
3. Carefully unplug the photomultiplier
tube from the socket.
4. Plug a new tube into the socket.
Rosemount Analytical Inc. A Division of Emerson Process Management Routine Servicing 5-5
Instruction Manual
748214-V
June 2009
Model 951C
5. Orient the metal shield and black
plastic insulator as noted in step 2.
6. Carefully rotate and insert the tube,
shield and cover into the housing.
Orient as noted in step 1.
5-4 OZONE GENERATION SYSTEM
This system consists of the ultraviolet lamp,
lamp housing, and power supply. Refer to
Figure 6-1 for location and details of mounting.
WARNING
TOXIC CHEMICAL HAZARD
The ozone generator lamp contains
mercury. Lamp breakage could result in
mercury exposure. Mercury is highly toxic
if absorbed through skin or ingested, or if
vapors are inhaled. Handle lamp assembly
with extreme care.
If lamp is broken, avoid skin contact and
inhalation in the area of the lamp or the
mercury spill. Immediately clean up and
dispose of the mercury spill and lamp
residue as follows:
•
Wearing rubber gloves and goggles,
collect all droplets of mercury by
means of a suction pump and aspirator
bottle with long capillary tube.
Alternatively, a commercially available
mercury spill clean-up kit, such as J. T.
Baker product No. 4439-01, is
recommended.
•
Carefully sweep any remaining
mercury and lamp debris into a dust
pan. Carefully transfer all mercury,
lamp residue and debris into a plastic
bottle which can be tightly capped.
Label and return to hazardous material
reclamation center.
Do not place in trash, incinerate or flush
down sewer. Cover any fine droplets of
mercury in non-accessible crevices with
calcium polysulfide and sulfur dust.
a. Lamp/Housing Removal
To remove the lamp and housing, do the
follow:
1. Disconnect power from the instrument.
2. Release pressure from SAMPLE and
AIR supplies.
3. Disconnect the air supply tubing from
the front of the housing.
4. Disconnect the ozone tube leading to
the reaction chamber.
5. Disconnect the power cable from the
Power Supply.
6. Uncouple the two Velcro straps which
secure the housing to power supply.
7. Lift the housing from the analyzer.
b. UV Lamp Replacement
To replace the lamp, do the following:
1. Unscrew and remove end cap.
2. Unscrew aluminum outer lamp housing tube from lamp base, using care
not to hit or touch lamp assembly.
NOTE:
Do not touch lamp. Fingerprints may
cause a decrease in lamp output.
3. Replace O-ring in lamp base with new
O-ring supplied in kit.
4. Insert replacement lamp assembly using care not to hit or touch lamp housing.
5. Insert new O-ring into new end cap.
Screw end cap onto end of lamp
housing.
Replace the lamp and housing by reversing the steps in this section.
5-6 Routine Servicing Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
c. Power Supply Removal
To remove the Power Supply, do the following:
Refer to Figure 6-1.
1. Remove the lamp and housing as in
Section 5-4b.
2. Disconnect the power lead from the
Power Supply Board.
3. Remove the two screws which secure
the Power Supply to the bottom plate
of the analyzer.
4. Lift the Power Supply from the analyzer.
5. Replace the Power Supply by reversing the order of the steps in this section.
5-5 CONVERTER ASSEMBLY
To check the heater blanket, verify the continuity of the heater coil.
To check the temperature sensor, refer to
Section 3-4 and measure its resistance when
instrument power is off (should be about 440
ohms) and when instrument power is on
(should range from 800 to 1,000 ohms). See
Table 3-1.
than the outlet tube. Further, the outlet
tube and the sample capillary (P/N
615989) connect to the same stainless
steel tee.
3. Release the assembly and disconnect the
heater and sensor connectors from the
temperature control board.
4. Remove the lacing from the heater blanket, and remove the converter tube. Note
the position of the temperature sensor
and its leads as the aluminum foil is unwrapped.
5. Replace the defective part and reassemble. The temperature sensor should contact the converter tube with the top of the
sensor at the midpoint of the converter.
Route sensor leads axially to the outer
end.
6. Condition the converter as described in
Sections 3-4 and 3-5.
5-6 SERVICING ELECTRONIC CIRCUITRY
For troubleshooting the electronic system, refer to Section 4.0 and the appropriate pictorial
diagrams at the back of the manual. The electronic system utilizes printed circuit boards
with solid-state components. After a malfunction is traced to a particular board, the recommended procedure is to return it to the
factory for repair.
To remove the glass converter tube (see
Figure 6-4):
1. Carefully disconnect the blue silicon connectors from the ends of the inlet and outlet tubes.
2. The inlet tube is partially filled with glass
wool and has a larger inside diameter
Rosemount Analytical Inc. A Division of Emerson Process Management Routine Servicing 5-7
Instruction Manual
748214-V
June 2009
Model 951C
5-8 Routine Servicing Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
748214-V
Model 951C
June 2009
SECTION 6
REPLACEMENT PARTS
WARNING
PARTS INTEGRITY
Tampering with or unauthorized substitution of components may adversely affect safety of this product.
Use only factory-approved components for repair.
6-1 MATRIX
Each analyzer is configured per the customer
sales order. Below is the 951C sales matrix
which lists the various configurations avail-
To identify the configuration of an analyzer,
locate the analyzer name-rating plate. The
sales matrix identifier number appears on the
analyzer name-rating plate.
able.
Model Description
951C Process Chemiluminescence NOx Analyzer (19" Rack Mount) (951C)
Level 1 Ranges
01 Low Ranges: 0-10, 0-25, 0-100, 0-250 ppm NOx
02 High Ranges: 0-100, 0-250, 0-1000, 0-2500 ppm NOx
04 Mid Ranges: 0-20, 0-50, 0-200, 0-500 ppm NOx
Level 2 Output
01 Selectable: 0-5 VDC, 0/4-20 mA
Level 3 Case
01 Standard
Level 4 Spare
4 00 None
Level 5 Sample Restrictor
01 Standard sample inlet, restrictor included
02 User controlled sample flow (no sample restrictor included)
Rosemount Analytical Inc. A Division of Emerson Process Management Replacement Parts 6-1
Model 951C
Instruction Manual
748214-V
June 2009
6-2 CIRCUIT BOARD REPLACEMENT POLICY
In most situations involving a malfunction of a
circuit board, it is more practical to replace the
board than to attempt isolation and replacement of the individual component. The cost of
test and replacement will exceed the cost of a
rebuilt assembly from the factory.
The following list does not include individual
electronic components. If circumstances necessitate replacement of an individual component which can be identified by inspection or
from the schematic diagrams, obtain the replacement component from a local source of
supply.
6-3 REPLACEMENT PARTS
The following parts are recommended for routine maintenance and troubleshooting of the
Model 951C NOX Analyzer. If the troubleshooting procedures do not resolve the problem, contact your local Rosemount Analytical
service office. A list of Rosemount Analytical
Service Centers is located in Section 7.
a. Common Parts
Refer to Figure 6-1.
655519 Air Restrictor Fitting
657091 Capacitor Assembly
655166 Capillary, Bypass
655589 Capillary, Sample Hi
623719 Capillary, Sample Lo
654068 Temperature Control Assembly
654070 Converter Assembly
655303 Exhaust Fan
654052 Fan Assembly
898587 Fuse 3.15 A
902413 Fuse 6.25 A
654390 I/O Assembly
652173 Ozone Generator
658156 Ozone Generator UV Lamp
Replacement Kit
655129 Ozone Generator Power Supply
654062 Photomultiplier Assembly
655332 Power Supply Assembly
662273 Pressure Switch
623936 Sample Flow Restrictor
644055 Sample Pressure Gauge
815187 Sample Regulator
622917 Sensor, Temperature
6A00337G01/02/03 Signal/Control Board
654878 Transformer/Inductor Assembly
Rosemount Analytical Inc. A Division of Emerson Process Management Replacement Parts 6-3
Model 951C
Case Heater Temperature
Control Assembly 654068
(See
Figure 6-4
Fan Assembly
654052
Pressure Switch
662273
Power Supply Assembly
655332
)
Photomultiplier Assembly
654062 (See
Sample Regulator
815187
Figure 6-1. Major Assemblies of the Model 951C
Figure 6-2
Sample Pressure Gauge
644055
)
I/O Assembly
654390
Air Restrictor
655519 (on Ozone Generator inlet)
Ozone Generator Power Supply
655129
Instruction Manual
Transformer/Inductor Assembly
654878
Sample Flow Restrictor
623936
Converter Assembly
654070 (See
Ozone Generator 658156
UV Lamp Replacement Kit 658156
Sensor
622917
748214-V
June 2009
Exhaust Fan
655303
Figure 6-3
)
Rosemount Analytical Inc. A Division of Emerson Process Management Replacement Parts 6-3
Instruction Manual
630916
PVC Tube
654943
636318
PVC Tube
748214-V
June 2009
Model 951C
b. Photomultiplier Assembly 654062
Refer to Figure 6-2.
654943 Housing
649541 Insulating Washer
636318 Magnetic Shield
630916 Magnetic Shield
Magnetic Shield
001522 O-Ring
008423 O-Ring, Photomultiplier
655168 Photomultiplier Tube
654381 Reaction Chamber
654086 Socket Assembly
639722 Thermal Shield
Thermocooler Housing
O-Rings 001522
Socket Assembly
654086
Photomultiplier Tube
655168
O-Ring 008423
Reaction Chamber 654381
Insulating Washer 649541
Thermal Shield 639722
Magnetic Shield
Magnetic Shield
Photomultiplier Tube
Photomultiplier Tube and Magnetic
Shield (PN 630916) to be Flush
Note: Silicone lubricant to be applied to o-rings.
Figure 6-2. Photomultiplier Housing Assembly
6-4 Replacement Parts Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
c. Converter Assembly 654070
Refer to Figure 6-3.
632784 Connector, Blue Silicone
657127 Heater
632782 Temperature Sensor
632795 Tube
Connectors, Glass
Tube
632784
Converter Tube - Packed
632795
Instruction Manual
748214-V
June 2009
Temperature Sensor
632782
Heater
657127
Figure 6-3. Converter Assembly
Rosemount Analytical Inc. A Division of Emerson Process Management Replacement Parts 6-5
Instruction Manual
748214-V
June 2009
d. Temperature Control Assembly 654068
Refer to Figure 6-4.
622733 Fan
622732 Heater
655335 Temperature Control Board
900492 Thermal Fuse
Figure 6-4. Case Heater Temperature Control Assembly
Model 951C
6-6 Replacement Parts Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
748214-V
June 2009
RETURN OF MATERIAL
7-1 RETURN OF MATERIAL
If factory repair of defective equipment is required, proceed as follows:
1. Secure a return authorization from a
Rosemount Analytical Inc. Sales Office or
Representative before returning the
equipment. Equipment must be returned
with complete identification in accordance
with Rosemount instructions or it will not
be accepted.
Rosemount CSC (Customer Service Center) will provide the shipping address for
your instrument.
In no event will Rosemount be responsible for equipment returned without proper
authorization and identification.
2. Carefully pack the defective unit in a
sturdy box with sufficient shock absorbing
material to ensure no additional damage
occurs during shipping.
3. In a cover letter, describe completely:
• The symptoms that determined the
equipment is faulty.
• The environment in which the equip-
ment was operating (housing,
weather, vibration, dust, etc.).
• Site from where the equipment was
removed.
• Whether warranty or non-warranty
service is expected.
• Complete shipping instructions for the
return of the equipment.
4. Enclose a cover letter and purchase order
and ship the defective equipment according to instructions provided in the Rosemount Return Authorization, prepaid, to
the address provided by Rosemount
CSC.
Rosemount Analytical Inc.
Process Analytic Division
Customer Service Center
1-800-433-6076
Model 951C
SECTION 7
If warranty service is expected, the defective
unit will be carefully inspected and tested at
the factory. If the failure was due to the conditions listed in the standard Rosemount warranty, the defective unit will be repaired or
replaced at Rosemount’s option, and an operating unit will be returned to the customer in
accordance with the shipping instructions furnished in the cover letter.
For equipment no longer under warranty, the
equipment will be repaired at the factory and
returned as directed by the purchase order
and shipping instructions.
7-2 CUSTOMER SERVICE
For order administration, replacement Parts,
application assistance, on-site or factory repair, service or maintenance contract information, contact:
Rosemount Analytical Inc.
Process Analytic Division
Customer Service Center
1-800-433-6076
7-3 TRAINING
A comprehensive Factory Training Program of
operator and service classes is available. For
a copy of the Current Operator and Service
Training Schedule contact :
Rosemount Analytical Inc.
Process Analytic Division
Customer Service Center
1-800-433-6076
7-2 Replacement Parts Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
748214-V
June 2009
Model 951C
7-2 Return of Material Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
SECTION 8
INDEX
2
230 VAC conversion, 2-3
A
Air (U.S.P. Breathing Grade), 2-5
AIR inlet
adequate air pressure, 3-3
setpoint pressure, 3-3
analyzer
installation location, 2-3
mount near sample, 2-3
operating temperature, 2-3
warm-up, 7, 3-3
C
Contamination of Reaction Chamber or Sample Flow
System, 5-2
converter
glass converter tube, 5-7
heater blanket, 5-7
measuring efficiency, 3-9
optimizing operating temperature, 3-7
temperature check, 3-7
temperature sensor, 5-7
converter temperature
adjustment, 3-7
recommended periodic check, 3-7
current output
adjustment, 2-3
Current recorder connections
cable specifications, 2-3
hookup, 2-3
routing, 2-3
cylinders, air/gas
location, 2-3
D
display, 3-1
DP SELECT jumpers, 3-3
E
Establish correct flow of upscale standard gas, 3-4
Establish correct pressure for air, 3-4
Establish correct pressure of sample gas, 3-4
Instruction Manual
748214-V
June 2009
establish correct pressure of zero gas, 3-4
Excessive Photomultiplier Dark Current, 5-2
F
flow rate, measuring, 5-3
flow rate, subnormal, 5-3
I
Inability to obtain a flow of one liter per minute at the
EXHAUST outlet, 3-4
internal SAMPLE pressure, 3-1
adjustment, 3-1
O
output connections
routing, 2-3
ozonator air
supply pressure, 7
ozone generation system, description, 5-6
ozone generation system, power supply removal, 5-
7
ozone generation system, removal, 5-6
ozone generation system, UV lamp replacement, 5-7
ozone lamp
output check, 5-2
OZONE pressure
determination, 3-1
nominal, 3-1
P
photomultiplier tube, 1-1, 4-1, 5-1, 5-2, 5-3, 5-4, 5-6
photomultiplier tube, description, 5-5
potentiometric recorder connections
cable specifications, 2-3
hookup, 2-3
routing, 2-3
Power connections
cable type, 2-3
hookup, 2-2
routing, 2-3
PPM RANGE Switch, 3-3
R
Range2 Select jumpers, 3-3
Rosemount Analytical Inc. A Division of Emerson Process Management Index 8-1
Instruction Manual
748214-V
June 2009
Model 951C
reaction chamber, 4-1, 4-2, 5-1, 5-2, 5-3, 5-4, 5-5, 5-
6
reaction chamber, alternate cleaning procedure, 5-5
reaction chamber, standard cleaning procedure, 5-5
Return Authorization, 7-2
S
sample gas
establish correct pressure, 7
supply pressure, 7
shutdown, 3-6
Span Gas, 2-5
supply pressure, 2-5
T
thermoelectric cooler, 5-4
U
Upscale Calibration, 8
PPM RANGE switch, 3-6
RANGE1 control, 3-6
sensitivity, 3-6
supply gas, 3-6
Z
Zero Calibration, 7
PPM RANGE switch, 3-6
RANGE1 control, 3-6
ZERO control, 3-6
zero display reading, inability to obtain, 5-2
zero gas
establish correct pressure, 7
supply pressure, 7
8-4 Index Rosemount Analytical Inc. A Division of Emerson Process Management
Model 951C
Instruction Manual
748214-V
June 2009
LIST OF DRAWINGS
Drawing 1-1. Panel Cutout / Installation Drawing
Rosemount Analytical Inc. A Division of Emerson Process Management List of Drawings
Instruction Manual
748214-V
June 2009
Model 951C
Drawing 1-2 Flow Diagram, Lo/Mid Range
Rosemount Analytical Inc. A Division of Emerson Process Management
List of Drawings
Model 951C
Instruction Manual
748214-V
June 2009
Drawing 1-3 Flow Diagram, Hi Range
Rosemount Analytical Inc. A Division of Emerson Process Management List of Drawings
Instruction Manual
748214-V
June 2009
Goods and part(s) (excluding consumables) manufactured by Seller are warranted to be free from
defects in workmanship and material under normal use and service for a period of twelve (12)
months from the date of shipment by Seller. Consumables, glass electrodes, membranes, liquid
junctions, electrolyte, o-rings, etc., are warranted to be free from defects in workmanship and
material under normal use and service for a period of ninety (90) days from date of shipment by
Seller. Goods, part(s) and consumables proven by Seller to be defective in workmanship and/or
material shall be replaced or repaired, free of charge, F.O.B. Seller's factory provided that the
goods, part(s) or consumables are returned to Seller's designated factory, transportation charges
prepaid, within the twelve (12) month period of warranty in the case of goods and part(s), and in
the case of consumables, within the ninety (90) day period of warranty. This warranty shall be in
effect for replacement or repaired goods, part(s) and the remaining portion of the ninety (90) day
warranty in the case of consumables. A defect in goods, part(s) and consumables of the
commercial unit shall not operate to condemn such commercial unit when such goods, part(s)
and consumables are capable of being renewed, repaired or replaced.
The Seller shall not be liable to the Buyer, or to any other person, for the loss or damage directly
or indirectly, arising from the use of the equipment or goods, from breach of any warranty, or from
any other cause. All other warranties, expressed or implied are hereby excluded.
Model 951C
WARRANTY
IN CONSIDERATION OF THE HEREIN STATED PURCHASE PRICE OF THE GOODS,
SELLER GRANTS ONLY THE ABOVE STATED EXPRESS WARRANTY. NO OTHER
WARRANTIES ARE GRANTED INCLUDING, BUT NOT LIMITED TO, EXPRESS AND IMPLIED
WARRANTIES OR MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
Limitations of Remedy. SELLER SHALL NOT BE LIABLE FOR DAMAGES CAUSED BY
DELAY IN PERFORMANCE. THE SOLE AND EXCLUSIVE REMEDY FOR BREACH OF
WARRANTY SHALL BE LIMITED TO REPAIR OR REPLACEMENT UNDER THE STANDARD
WARRANTY CLAUSE. IN NO CASE, REGARDLESS OF THE FORM OF THE CAUSE OF
ACTION, SHALL SELLER'S LIABILITY EXCEED THE PRICE TO BUYER OF THE SPECIFIC
GOODS MANUFACTURED BY SELLER GIVING RISE TO THE CAUSE OF ACTION. BUYER
AGREES THAT IN NO EVENT SHALL SELLER'S LIABILITY EXTEND TO INCLUDE
INCIDENTAL OR CONSEQUENTIAL DAMAGES. CONSEQUENTIAL DAMAGES SHALL
INCLUDE, BUT ARE NOT LIMITED TO, LOSS OF ANTICIPATED PROFITS, LOSS OF USE,
LOSS OF REVENUE, COST OF CAPITAL AND DAMAGE OR LOSS OF OTHER PROPERTY
OR EQUIPMENT. IN NO EVENT SHALL SELLER BE OBLIGATED TO INDEMNIFY BUYER IN
ANY MANNER NOR SHALL SELLER BE LIABLE FOR PROPERTY DAMAGE AND/OR THIRD
PARTY CLAIMS COVERED BY UMBRELLA INSURANCE AND/OR INDEMNITY COVERAGE
PROVIDED TO BUYER, ITS ASSIGNS, AND EACH SUCCESSOR INTEREST TO THE GOODS
PROVIDED HEREUNDER.
Force Majeure. Seller shall not be liable for failure to perform due to labor strikes or acts beyond
Seller's direct control.
Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
WORLD HEADQUARTERS
748214-V
June 2009
Model 951C
ROSEMOUNT ANALYTICAL EUROPE
AND AMERICAS
Emerson Process Management
Rosemount Analytical Inc.
6565 P Davis Industrial Parkway
Solon, OH 44139 USA
T 440.914.1261
Toll Free in US and Canada 800.433.6076
F 440.914.1271
e-mail: gas.csc@Emerson.com
www.raihome.com
National Response Center 800.654.7768
ASIA-PACIFIC
Emerson Process Management
Asia Pacific Private Limited
1 Pandan Crescent
Singapore 128461
Republic of Singapore
T 65 6 777 8211
F 65 6 777 0947
e-mail: analytical@ap.emersonprocess.com
© Rosemount Analytical Inc. 2009
Emerson Process Management
GmbH & Co. OHG
Industriestrasse 1
63594 Hasselroth
Germany
T 49 6055 884 0
F 49 6055 884209
EUROPE
Emerson Process Management
Shared Services Limited
Heath Place
Bognor Regis
West Sussex PO22 9SH
England
T 44 1243 863121
F 44 1243 845354
LATIN AMERICA
Emerson Process Management
Rosemount Analytical
11100 Brittmoore Park Road
Houston, TX 77041 USA
T 713.467.6000
F 713.827.3328F 49 6055 884209
MIDDLE EAST AND AFRICA
Emerson Process Management
EPM Building
P.O. Box 17033
Jebel Ali Free Zone
Dubai, United Arab Emirates
T 971 4 8835235
F 971 4 8835312
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