This manual is applicable to Model 400A, Catalog Number 194104 with
Serial Numbers beginning with 1999999.
http://www.processanalytic.com
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
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.
to ensure they continue to operate within their
•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.
SNOOP is a registered trademark of NUPRO Co.
Emerson Process Management
Rosemount Analytical Inc.
Process Analytic Division
1201 N. Main St.
Orrville, OH 44667-0901
T (330) 682-9010
F (330) 684-4434
e-mail: gas.csc@EmersonProcess.com
ii Contents Rosemount Analytical Inc. A Division of Emerson Process Management
Model 400A
Figure 2-1. Range Input-Output Board..................................................................................... 2-5
Figure 3-1. Power Switch Location .......................................................................................... 3-2
Figure 3-2. Typical Curves of Downscale Response vs. Time for Various Hydrocarbons ...... 3-3
Figure 3-3. Example 1 Display ................................................................................................. 3-6
Figure 3-4. Example 2 Display ................................................................................................. 3-7
Figure 3-5. Example 3 Display ................................................................................................. 3-7
Figure 4-1. Typical Curve of Analyzer Response vs. Pressure Setting on Sample Pressure . 4-2
Figure 4-2. Typical Curves of Analyzer Response vs. Pressure Setting on Fuel Pressure
Figure 4-3. Typical Curves of Analyzer Response vs. Pressure Setting on Air Pressure
620424 Schematic Diagram, Preamplifier
620429 Schematic Diagram, Main Electronics
620434 Schematic Diagram, Isolated V/I
620439 Schematic Diagram, Isolated Digital Control
620447 Schematic Diagram, Temperature Controller
621072 Pictorial Wiring Diagram, Model 400A
621073 Installation Drawing, Model 400A
622883 Flow Diagram, Model 400A
623190 Burner Parts List
Rosemount Analytical Inc. A Division of Emerson Process Management Contents iii
Instruction Manual
748023-X
November 2002
Model 400A
iv Contents Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
Model 400A
November 2002
PREFACE
The purpose of this manual is to provide information concerning the components,
functions, installation and maintenance of the 400A.
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 .
748023-X
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
748023-X
November 2002
Model 400A
SAFETY SUMMARY
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 Model 400A Hydrocarbon Analyzer should
be thoroughly familiar with and strictly follow the instructions in this manual. Save these
instructions.
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.
For safety and proper performance, this instrument must be connected to a properly grounded
three-wire source of power.
WARNING.
PARTS INTEGRITY
Tampering or unauthorized substitution of components may adversely affect safety of this product.
Use only factory documented components for repair.
WARNING.
POSSIBLE EXPLOSION HAZARD
Protection against explosion depends upon special fuel flow limiting restrictor in fuel inlet fitting.
Do not remove fuel inlet restrictor. Replace only with factory supplied fitting.
P-2 Preface Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
Model 400A
WARNING .
POSSIBLE EXPLOSION HAZARD
Do not apply power to analyzer or ignite burner until all leak checks have been performed and until
the environment of the analyzer has been determined to be non-hazardous. See Section 2-4 on
page 2-2 for leak check procedure.
This instrument uses a fuel containment hydrogen. The instrument is designed to protect against
the formation of an explosive gas mixture within the enclosure. It must NOT be operated if the internal ventilation fan is not functioning. Do NOT operate without factory installed fuel flow restrictor in place.
Check the fuel supply and containment system for leaks, both inside and outside the analyzer,
upon installation, before initial startup, during routine maintenance, or any time the integrity of the
fuel containment system is broken, to assure that the system is leak-tight.
In the event that flammable sample is to be introduced into this analyzer, it must be equipped with
the accessory kit, PN 624080, which restricts sample flow and provides automatic sample shut-off
in the event of burner flame-out. Do not operate without sample flow restrictor in place. The sample containment system should also be thoroughly leak checked. This kit is designed considering
application on hydrogen sample (LEL+4% v/v). The instrument must not be used on a sample having a LEL of less than 4% in air.
November 2002
748023-X
This analyzer is designed for use in unclassified (general purpose) environments that do not contain flammable (explosive) materials. It should be installed in an unconfined, ventilated space.
CAUTION .
HIGH PRESSURE GAS CYLINDERS
For safety and proper performance this instrument must be connected to a properly grounded
three-wire source of power.
This analyzer requires periodic calibration with known zero and standard gases. See General Precautions for Handling and Storing High Pressure Cylinders on page 4.
Rosemount Analytical Inc. A Division of Emerson Process Management Preface P-3
Instruction Manual
748023-X
November 2002
Model 400A
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
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.
°
F (52°C). A flame should
P-4 Preface Rosemount Analytical Inc. A Division of Emerson Process Management
Instruction Manual
Model 400A
DOCUMENTATION
The following Model 400A instruction materials are available. Contact Customer Service Center or the
local representative to order.
748023 Instruction Manual (this document)
748023-X
November 2002
Rosemount Analytical Inc. A Division of Emerson Process Management Preface P-5
Instruction Manual
748023-X
November 2002
Model 400A
P-6 Preface Rosemount Analytical Inc. A Division of Emerson Process Management
Model 400A
DESCRIPTION AND SPECIFICATIONS
The Model 400A Hydrocarbon Analyzer
automatically and continuously measures the
concentration of hydrocarbons in a gas
stream. Typical applications include monitoring atmospheric air for low-level hydrocarbon
contaminants and determining the hydrocarbon content of exhaust emissions from internal combustion engines.
Instruction Manual
748023-X
November 2002
SECTION 1
1-1 ANALYZER MOUNTING OPTIONS
WARNING
INSTALLATION
For safety, the analyzer should be installed
in a non-confined, ventilated space.
The analyzer utilizes the flame ionization
method of detection. The sensor is a burner in
which a regulated flow of sample gas passes
through a flame sustained by regulated flows
of a fuel gas and air. Within the flame, the hydrocarbon components of the sample stream
undergo a complex ionization that produces
electrons and positive ions. Polarized electrodes collect these ions, causing current to
flow through an electronic measuring circuit.
The ionization current is proportional to the
rate at which carbon atoms enter the burner,
and is therefore a measure of the concentration of hydrocarbons in the original sample.
The analyzer provides readout on a
front-panel digital display and a selectable
output for an accessory recorder.
To ensure stable, drift-free operation, particularly in high-sensitivity applications, an internal
temperature controller maintains the analyzer
interior at a constant 48°C. This feature minimizes temperature dependent variations in (a)
electronic current-measuring circuitry, and (b)
adsorption/desorption equilibrium of background hydrocarbons within the internal flow
system.
To minimize system response time, an internal sample-bypass feature provides high velocity sample flow through the analyzer.
The Model 400A may be equipped with various optional features in addition to, or instead
of, the standard features of the basic instrument. The following paragraphs provide brief
descriptions of the principal standard and optional features.
The standard analyzer is housed in a case
designed for bench-top use, or if desired, the
analyzer may be mounted in a cabinet or rack
using RETMA spaced mounting holes. Outline
dimensions are shown on drawing 621073.
1-2 FUEL GAS OPTIONS
For burner fuel gas, the standard analyzer requires 40% hydrogen/60% nitrogen or helium.
Through installation of the optional 400A hydrogen fuel kit (P/N 622576), the analyzer
may be converted to use 100% hydrogen.
This kit may be ordered as a factory installed
option or supplied as an option for installation
by the user.
The preferred type of fuel depends on the particular application and the characteristics of
the sample gas:
1. For measuring low-level hydrocarbons in
ambient air, or in other sample gas with
relatively constant oxygen content, 100%
hydrogen is preferable. It provides the
highest obtainable sensitivity and the
maximum stability. Zero drift caused by
ambient temperature variations of the fuel
cylinder is some what lower for 100% hydrogen than for mixed fuel. (With either
fuel, it is desirable to maintain cylinder
temperature constant.)
2. For monitoring vehicular exhaust emissions, or other sample gas with varying
oxygen content, mixed fuel is preferable;
and a hydrogen/helium mixture is more
desirable than a hydrogen/nitrogen mix-
Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 1-1
Instruction Manual
748023-X
November 2002
Model 400A
ture. With this type of sample, the use of
mixed fuel gas minimizes the error introduced by oxygen synergism.
An effective way to reduce the effect of internal oxygen is to dilute it with an inert gas. This
might be accomplished by a constant dilution
of sample and calibration gases ahead of the
burner but it is simpler and more accurate to
provide that diluent in the form of premixed
fuel. Both nitrogen and helium have been
used as a diluent, but helium has proven to be
most effective in improving the equality of response to the various species of hydrocarbons.
As indicated earlier the flame output signal is
optimum when the ratio of hydrogen flow to
inert flow is about 40/60; therefore, this is the
chosen composition for hydrogen/helium premixed fuel.
The sample flow is kept low to maximize the
dilution effect while still providing adequate
sensitivity. The burner air flow is normally
about four times the fuel flow, and changes
have little effect on signal strength. For a
given sample flow, the signal can be optimized by adjusting the fuel flow rate.
Typical flow rates with premixed fuel:
Fuel 100cc/min
Sample 7 cc/min
Air 400 cc/min
It is worth noting that with a 40/60 premixed
fuel, the above flows amount to 40 cc (8%)
hydrogen, 67 cc (13%) inert plus sample and
400 cc (79%) air, which compare closely to
the 30 cc (8%) hydrogen, 45 cc (12%) inert/sample and 300 cc (80%) air given earlier
for straight hydrogen fuel.
Since the sample flow in the case of mixed
fuel operation is only about one-sixth of that
with straight hydrogen fuel, it is clear that
higher sensitivity is obtained with straight hydrogen fuel operation. However, in any application where the sample contains more than
one species of hydrocarbon and/or a varying
concentration of oxygen, the mixed fuel operation should be used.
The mixed fuel is recommended, not only for
sample containing variable concentrations of
oxygen, but also for two specific pure gas applications. The first is the case of pure hydrogen samples. The other is the case of pure
oxygen samples. If straight oxygen samples
are used with straight hydrogen fuel, the mixture entering the burner is essentially 40%
H2/60% 0
ble signal. The mixed fuel works better. Note
that the choice of fuel determines certain analyzer characteristics, as tabulated in Table 1-1
on page 1-3.
1-3 OUTPUT OPTIONS
The standard analyzer provides (a) direct digital readout in percent of fullscale on a
front-panel display calibrated linearly from 0 to
100.0%, (b) a selectable buffered output of
0.1 VDC, 1 VDC or 5 VDC suitable for a re-
corder and W a 0 to VDC unbuffered accessory output.
An isolated output of 4 to 20 mA DC (max.
load resistance 700 ohms) is obtainable
through use of the optional current output
board, P/N 620433, installed either during factory assembly or as a subsequent addition.
When installed, this board uses the accessory
0 to 5 VDC output as an input signal and replaces this function at the output terminals.
, which tends to produce an unsta-
2
1-2 Description and Specifications Rosemount Analytical Inc. A Division of Emerson Process Management
Model 400A
Instruction Manual
748023-X
November 2002
ANALYZER
CHARACTERISTICS
Fullscale Sensitivity Adjustable from 1 ppm CH4 to 2% CH4
Fuel Consumption 35 to 40 cc/min 75 to 80 cc/min
Operating Range for SAMPLE
Pressure Regulator
Table 1-1. Fuel Gas vs. Analyzer Characteristics
1-4 SAMPLE PUMP OPTION
To provide the required sample flow, the
sample gas must be under adequate pressure
when applied to the analyzer inlet. Refer to
Section 2-2a on page 2-1. To permit analysis
of gases at atmospheric or sub-atmospheric
pressure, the analyzer may be shipped with a
sample pump accessory, P/N 621062.
1-5 GAS SAFETY FEATURES
The Model 400A is designed to provide a high
degree of operational safety. In all analyzers,
a front-panel LED indicates that the burner
flame is lit. In addition, fuel gas is automatically shut off when a flame-out condition occurs.
All tubing ahead of the burner is rigid metallic
tubing made up with ferrule/nut type compression fittings. However, should there be an internal fuel leak, an inlet fuel flow limiting
restrictor, ventilation holes in the enclosure
and an internal circulation fan serve to dilute
and dissipate the hydrogen fuel for a worst
case leak to a safety factor below 25% of the
LEL of hydrogen. The design basis for this
system presumes 100% hydrogen fuel at 50
psig inlet pressure. 40% hydrogen fuel and
100% H
2
4 to 5 psig (27 to 34.5 kPa)
40% H2/60% N
or 40% H
/He
2
2
Adjustable from 4 ppm
to 10% CH4
CH
4
1.5 to 5 psig
(10.3 to 34.5 kPa)
lower inlet pressure serve to further reduce
hydrogen concentration in the event of a leak.
In reality, an open fitting leak would never occur. As a leak developed the burner would
eventually be starved of fuel and flame-out
would occur at a leak equivalent of a loss of
about 20 psig fuel pressure, thus actuating the
fuel shut-off solenoid valve system.
If the sample is flammable, accessory kit P/N
624080, must be utilized. This kit provides a
restrictor to limit sample flow and a solenoid
valve to shut-off sample in the event of burner
flame-out. The design basis for this kit presumes a maximum sample flow rate of 470
cc/min and a sample with LEL not below that
of hydrogen (4% v/v in air).
WARNING
POSSIBLE EXPLOSION HAZARD
Protection against explosion depends
upon special fuel flow limiting restrictor in
fuel inlet fitting. Do not remove fuel inlet
restrictor. Replace only with factory supplied fitting.
Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 1-3
Instruction Manual
748023-X
November 2002
1-6 SPECIFICATIONS
Power Requirements..................... 115 VAC ±10%, 50/60 ±3 Hz, 250 W
Ambient Temperature.................... 32°F to 110°F (0°C to 43°C)
Case Temperature ........................ Controlled at 122°F (50°C)
Ambient Humidity .......................... 95% relative humidity, but not in excess of 34°C wet bulb
temperature.
Dimensions.................................... 8.75 in (22.2 cm) H
18.75 in. (47.6 cm) W
15.88 in. (39.7 cm) D
Recommended panel cutout is 17.75 in. X 8 25 in. (45.1 cm x 21.0
cm).
May be mounted in standard 19 inch rack.
Weight ........................................... 22 lbs (10 kg)
Repeatability.................................. 1% of fullscale for successive identical samples
Response Time ............................. 90% of fullscale in 0.6 seconds with sample bypass flow at 3
liters/minute
Analyzer Fullscale Sensitivity
Standard .............................. Adjustable from 4 ppm CH
CH
to 10% CH4 using high-range capillary.)
4
to 1% CH4. (Adjustable from 100 ppm
4
Equipped with 100%
Hydrogen Fuel Assembly .....Adjustable from 1 ppm CH4 to 0.25% CH
Analyzer Fuel Gas Requirements
Standard Analyzer ................ 75 to 80 cc/min premixed fuel consisting of 40% hydrogen and 60%
nitrogen or helium (THC <0.5 ppm) supplied at 45 to 50 psig (309
to 344 kPa) at instrument
Equipped with 100%
Hydrogen Fuel Assembly .....35 to 40 cc/min of clean, zero grade hydrogen (THC <0.5 ppm) at
45 to 50 psig (309 to 344 kPa) at instrument
Sample Gas Requirements
Non-Flammable Samples ..... 0.35 to 3.0 liters/minute at 5 to 10 psig (34 to 69 kPa)
Flammable Samples............. 470 cc/minute maximum for safety
1
Burner Air Requirements............... 350 to 400 cc/minute of zero grade (THC <1 ppm) air, supplied at
25 to 50 psig (172 to 344 kPa)
Sample Bypass Flow..................... 0.3 to 3.0 liters/minute
Stability .......................................... Electronic stability at maximum sensitivity is 1% of fullscale
throughout ambient temperature range of 32°F to 110°F (0°C to
43°C). Built-in temperature controller minimizes effect of ambient
temperature variations on internal flow and electronic systems.
Range ............................................ Eight ranges: 1, 2.5, 10, 25, 100, 250, 1000 and REMOTE.
In addition SPAN control provides continuously variable adjustment
within a dynamic range of 4:1
1
Safety design basis presumes flammable sample having LEL not less than that of hydrogen (4% v/v in air).
Model 400A
4
1-4 Description and Specifications Rosemount Analytical Inc. A Division of Emerson Process Management
Model 400A
Output............................................ 1) 0 to 5 VDC, 0 to 1 VDC, 0 to 0.1 VDC fully buffered - standard
Safety Features ............................. Flame-on indication and automatic flame-out fuel shutoff is
Contacts ........................................ Form A contact operates in parallel with flame-out fuel shut-off
Temperature Control ..................... Setpoint maintained at 122°F (50°C)
Data Display .................................. 3-1/2 digit LED, characters 0.52 inches high, range 0000 to 1999
Range Display ............................... 1 digit LED, character 0.52 inches high (1 to 7 normal ranges, 0 to
Remote Range Control.................. Standard, fully isolated range control and range ID is optional
Instruction Manual
748023-X
November 2002
(for 0 to 100.0%).
2) 4 to 20 mA isolated voltage to current - optional (maximum load
resistance 700 ohms)
3) 0 to 5 VDC accessory output un-buffered - standard (for 0 to
100.0%) available when current option is not used.
standard.
All metal tubing with ferrule/nut compression fittings to minimize potential fuel leaks.
Self-ventilated system maintains internal atmosphere below 25% of
LEL for worst case internal leakage.
solenoid contact rating (24 VDC at 1 A) for sample shut-off by use
of factory ordered kit (PN 624080) if sample is flammable
(hydrogen).
remote control)
Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 1-5
Instruction Manual
748023-X
November 2002
Model 400A
1-6 Description and Specifications Rosemount Analytical Inc. A Division of Emerson Process Management
Model 400A
Instruction Manual
748023-X
November 2002
SECTION 2
INSTALLATION
2-1 FACILITY PREPARATION
Sections 2-2a and 2-2b provide information
that may be required prior to installation. Refer to drawing 621073 for installation dimensions.
a. Location
Install analyzer in a clean area, not subject to excessive vibration or extreme
temperature variations. Preferably, the
analyzer should be mounted near the
sample stream, to minimize sample-transport time.
WARNING
INSTALLATION RESTRICTIONS
For safety, the analyzer should be installed
in a non-confined, ventilated space. Do
not block any of the vent holes at the top
of each side panel of the instrument as
they are part of the safety system.
A thermostatically controlled heating circuit holds internal temperature of the analyzer to the correct operating temperature
for ambient temperatures in the range
32°F to 110°F (0°F to 43°C).
The cylinders of fuel, air, and calibration
gas(es) should be located in an area of
relatively constant ambient temperature.
b. Utility Specifications
115 VAC 10% or 220 VAC 10%, 50/60
Hz, depending on unit specified.
2-2 FUEL AND AIR REQUIREMENTS
WARNING
PRESSURIZED GAS
Fuel, air and calibration gas cylinders are
under pressure. Mishandling of gas cylinders could result in death, injury or property damage. Handle and store cylinders
with extreme caution and in accordance
with manufacturer's instructions. Refer to
the list of general precautions, which follows Section 7 of this manual.
During normal operation, the analyzer uses
fuel and air to maintain the burner flame. Criteria for selection of these gases are given in
Sections 2-2a and 2-2b. In addition, the analyzer requires suitable standard gas(es) for
calibration. Refer to Section 3-1a on page 3-4.
Each gas used should be supplied from a tank
or cylinder equipped with a clean, hydrocarbon-free, two-stage regulator. In addition, a
shutoff valve is desirable. Install the gas cylinders in an area of relatively constant ambient
temperature.
a. Fuel Gas
The standard analyzer is equipped to use
only mixed fuel, i.e. 40% hydrogen/60%
nitrogen or helium. Such blends are supplied by many gas vendors specifically for
this use, with a guaranteed maximum total hydrocarbon content of 0.5 ppm,
measured as methane (THC < 0.5 ppm).
This specification should be used when
buying such mixtures.
NOTE
220 VAC requires an optional trans-
former mounted within the instrument.
Rosemount Analytical Inc. A Division of Emerson Process Management Installation 2-1
When the analyzer is equipped with the
optional hydrogen fuel kit, P/N 622576,
100% hydrogen fuel is to be used. This is
also supplied by many gas vendors specifically for this use, with the same guaranteed total hydrocarbon content (THC <
Instruction Manual
748023-X
November 2002
Model 400A
0.5 ppm) which, again, should be specified when buying the gas.
NOTE
Always assure the sample flow is present when using the 100% hydrogen
fuel option. Absence of sample flow
can result in burning of detector tip
when using 100% hydrogen.
b. Air
Burner air should also be relatively free of
hydrocarbons in order to assure a low
background signal. Several grades of air
are supplied by various gas vendors for
this use. A maximum total hydrocarbon
content of less than 1 ppm (THC < as a
zero standard).
An alternate source of pure air for burner
and zero gas can be provided by a diaphragm pump and heated palladium catalyst which effectively removes moderate
amounts of both hydrocarbons and carbon monoxide from normal ambient air on
a continuous basis.
2-3 SAMPLE HANDLING
CAUTION
BYPASS GAUGE PROTECTION
When applying sample pressures greater
than 5 psig, insure that the bypass regulator is fully open to protect the bypass
gauge.
Operating range for the internal sample pressure regulator is 4 to 5 psig (28 to 35 kPa) for
an analyzer using 100% hydrogen fuel, and
1.5 to 5 psig (10 to 35 kPa) for an analyzer
using mixed fuel. With either fuel, sample and
calibration gas(es) must be supplied to the
sample inlet at a pressure slightly, but not excessively higher than the desired setting on
the internal sample pressure regulator. The
criterion for correct supply pressure is that the
gas flow discharged from the by-pass outlet
must be between 0.5 and 3.0 liters/minute to
operate within the control range of the sample
pressure regulator, and preferably should be
between 2 and 3 liters/minute to minimize system response time.
Note that use of excessive bypass flow will
not only cause the sample pressure regulator
to operate outside its control range, but will
also result in rapid depletion of sample and
standard gases.
If the analyzer is equipped with the accessory
400A sample pump, P/N 621062, the acceptable pressure range at the pump inlet is approximately -1 to +2.5 psig (7 to 17 kPa). If
the pump is used, it will automatically provide
a sample bypass flow within the correct range.
If the analyzer is not equipped with sample
pump, adjustment of the bypass flow is obtainable by inserting an external flow controller or throttle valve into the external sample
line, upstream from the sample inlet. Flow
may be measured by connecting a flowmeter
to the by-pass outlet.
WARNING
POSSIBLE EXPLOSION ELAZARD
In the event that flammable sample is to be
introduced into this analyzer, it must be
equipped with the accessory kit P/N
624080, which restricts sample flow and
provides automatic sample shut-off in the
event of burner flameout. Do not operate
without sample flow restrictor in place.
The sample containment system should
also be thoroughly leak checked. This kit
is designed considering application on
hydrogen sample (LEL=4% v/v). The instrument must not be used on a sample
having a LEL less than 4% in air.
2-4 GAS CONNECTION AND LEAK CHECK
PROCEDURE
For external gas lines, the use of all new tubing throughout is strongly recommended.
Copper refrigeration tubing is preferred.
Stainless steel tubing is less desirable, because it contains hydrocarbon contaminants,
necessitating thorough cleaning before installation.
2-2 Installation Rosemount Analytical Inc. A Division of Emerson Process Management
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