Teledyne 2120XL User Manual
OPERATING INSTRUCTIONS FOR
Model 2120XL
Trace Nitrogen in Argon Analyzer
DANGER
This instrument is for analyzing nitrogen in argon only.
Do not introduce any flammable or toxic gases into this instrument.
Hazardous voltages exist on certain components internally which may be
lethal. Disconnect power before servicing.
Only authorized personnel should conduct maintenance and/or servicing.
Before conducting any maintenance or servicing, consult with authorized
supervisor/manager.
P/N M84744
11-27-13
Teledyne Analytical Instruments
Model 2120XL
Copyright © 2013 Teledyne Analytical Instruments
All Rights Reserved. No part of this manual may be reproduced, transmitted, transcribed,
stored in a retrieval system, or translated into any other language or computer language in
whole or in part, in any form or by any means, whether it be electronic, mechanical,
magnetic, optical, manual, or otherwise, without the prior written consent of Teledyne
Analytical Instruments, 16830 Chestnut Street, City of Industry, CA 91748.
Warranty
This equipment is sold subject to the mutual agreement that it is warranted by us free from
defects of material and of construction, and that our liability shall be limited to replacing or
repairing at our factory (without charge, except for transportation), or at customer plant at
our option, any material or construction in which defects become apparent within one year
from the date of shipment, except in cases where quotations or acknowledgements provide
for a shorter period. Components manufactured by others bear the warranty of their
manufacturer. This warranty does not cover defects caused by wear, accident, misuse,
neglect or repairs other than those performed by Teledyne or an authorized service center.
We assume no liability for direct or indirect damages of any kind and the purchaser by the
acceptance of the equipment will assume all liability for any damage which may result from
its use or misuse.
We reserve the right to employ any suitable material in the manufacture of our apparatus,
and to make any alterations in the dimensions, shape or weight of any parts, in so far as
such alterations do not adversely affect our warranty.
Important Notice
This instrument provides measurement readings to its user, and serves as a tool by which
valuable data can be gathered. The information provided by the instrument may assist the user
in eliminating potential hazards caused by his process; however, it is essential that all
personnel involved in the use of the instrument or its interface, with the process being
measured, be properly trained in the process itself, as well as all instrumentation related to it.
The safety of personnel is ultimately the responsibility of those who control process
conditions. While this instrument may be able to provide early warning of imminent
danger, it has no control over process conditions, and it can be misused. In particular, any
alarm or control systems installed must be tested and understood, both as to how they
operate and as to how they can be defeated. Any safeguards required such as locks, labels,
or redundancy, must be provided by the user or specifically requested of Teledyne at the
time the order is placed.
Therefore, the purchaser must be aware of the hazardous process conditions. The purchaser
is responsible for the training of personnel, for providing hazard warning methods and
instrumentation per the appropriate standards, and for ensuring that hazard warning devices
and instrumentation are maintained and operated properly.
Teledyne Analytical Instruments, the manufacturer of this instrument, cannot accept
responsibility for conditions beyond its knowledge and control. No statement expressed or
implied by this document or any information disseminated by the manufacturer or its
agents, is to be construed as a warranty of adequate safety control under the user’s process
conditions.
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Trace Nitrogen in Argon Analyzer
Specific Model Information
This instrument relies on the known spectrum emitted from a
plasma discharge from a distinct gas mixture of variable composition at
or near atmospheric pressure. This instrument cannot be used for
analysis on any gas or gas mixture other than nitrogen in argon or a
mixture specified at the time of purchase. Specific filters carefully
chosen and tested at the factory have been installed for the particular gas
mixture. Using this instrument to analyze any other gas mixture will
result in serious error. Consult the factory for additional information for
gas analysis not specified at the time of purchase.
Instrument Serial Number: _______________________
Instrument Range: _______________
Calibrated for: _______________
Background Gas: _______________
Zero Gas: _______________
Span Gas: _______________
Teledyne Analytical Instruments iii
Model 2120XL
Safety Messages
Your safety and the safety of others is very important. We have
provided many important safety messages in this manual. Please read
these messages carefully.
A safety message alerts you to potential hazards that could hurt you
or others. Each safety message is associated with a safety alert symbol.
These symbols are found in the manual and inside the instrument. The
definition of these symbols is described below:
GENERAL WARNING/CAUTION: Refer to the instructions for
details on the specific danger. These cautions warn
of specific procedures which if not followed could
cause bodily Injury and/or damage the instrument.
CAUTION: HOT SURFACE WARNING: This warning is specific to
heated components within the instrument. Failure to
heed the warning could result in serious burns to
skin and underlying tissue.
WARNING: ELECTRICAL SHOCK HAZARD: Dangerous voltages appear
within this instrument. This warning is specific to
an electrical hazard existing at or nearby the
component or procedure under discussion. Failure
to heed this warning could result in injury and/or
death from electrocution.
Technician Symbol: All operations marked with this symbol are to be
performed by qualified maintenance personnel only.
NOTE: Additional information and comments regarding a
specific component or procedure are highlighted in
No
Symbol
the form of a note.
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Trace Nitrogen in Argon Analyzer
CAUTION: THE ANALYZER SHOULD ONLY BE USED ONLY
FOR THE PURPOSE AND IN THE MANNER
DESCRIBED IN THIS MANUAL.
IF YOU USE THE ANALYZER IN A MANNER OTHER
THAN THAT FOR WHICH IT WAS INTENDED,
UNPREDICTABLE BEHAVIOR COULD RESULT
POSSIBLY ACCOMPANIED WITH HAZARDOUS
CONSEQUENCES.
This manual provides information designed to guide you through
the installation, calibration operation and maintenance of your new
analyzer. Please read this manual and keep it available.
Occasionally, some instruments are customized for a particular
application or features and/or options added per customer requests.
Please check the front of this manual for any additional information in
the form of an Addendum which discusses specific information,
procedures, cautions and warnings that may be peculiar to your
instrument.
Manuals do get lost. Additional manuals can be obtained from
Teledyne at the address given in the Appendix. Some of our manuals are
available in electronic form via the internet. Please visit our website at:
www.teledyne-ai.com.
Teledyne Analytical Instruments v
Model 2120XL
Table of Contents
List of Figures ................................................................ ix
List of Tables .................................................................. x
Introduction ..................................................................... 1
1.1 Overview 1
1.2 Typical Applications 1
1.3 Features 2
1.4 Front Panel 3
1.5 Rear Panel 5
1.6 Internal Components 6
1.7 Additional Safety Information 7
1.7.1 Detector Cautions 8
1.7.2 Basic Safety Requirements 9
1.7.3 Precautionary Labels 9
1.7.4 Summary of Known Hazards 10
1.7.4.1 Electrocution 10
1.7.4.2 Pressure 10
1.7.4.3 Purging 11
1.7.4.4 Safe Repair Procedures 11
1.7.4.5 General Precautions for Handling and Storing
High Pressure Gas Cylinders 11
Operational Theory ....................................................... 13
2.1 The Analyzer 13
2.2 Sample System 14
Installation ..................................................................... 17
3.1 Unpacking the Instrument 17
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Trace Nitrogen in Argon Analyzer
3.2 Choosing a Location 18
3.3 Mounting 18
3.4 Rear Panel Connections 19
3.5 Electrical Connections 20
3.5.1 Primary Input Power 20
3.5.2 50-Pin Equipment Interface Connector 20
3.5.3 RS-232 Port 26
3.6 Gas Connections 27
3.6.1 Typical Sample System 29
3.6.2 Gas Connections to the Instrument 31
3.7 Purging 31
3.8 Calibration 33
3.9 Installation Checklist 33
Operation....................................................................... 35
4.1 Powering Up the Analyzer 36
4.2 Zero and Span Calibration 36
4.3 Setup and Operation General Information 37
4.4 Using the Data Entry and Function Buttons 37
4.5 Analyzer Functions 38
4.5.1 System Menu 39
4.5.1.1 Digital Filter 40
4.5.1.2 Self-Test 41
4.5.1.3 Password Protection 42
4.5.1.4 Logout 46
4.5.1.5 ERR 46
4.5.1.6 Auto Calibration (Auto Cal) 47
4.5.1.7 Flow 49
4.5.1.8 Tracking During Calibration 49
4.5.1.9 Calibration Hold Timer (Calholdtimer) 50
4.5.1.10 The Model Screen 50
4.5.1.11 Analog Output Calibration (Out_Cal) 51
4.5.1.12 Linearize (Lin) 52
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Model 2120XL
4.5.2 The Zero and Span Functions 54
4.5.2.1 Before Calibration 54
4.5.2.2 Recommended Calibration Gases 55
4.5.2.3 Zero Cal 55
4.5.2.4 Span Calibration 57
4.5.3 The Range Function 59
4.5.4 The Alarms Function 60
4.6 The Analyze Function 62
4.7 Signal Output 62
Maintenance .................................................................. 65
5.1 Routine Maintenance 65
5.2 Routine Maintenance Schedule 65
5.3 Fuse Replacement 66
5.4 System Self Diagnostic Test 67
5.5 Error Screens 68
5.6 Sensor Replacement 69
Appendix ....................................................................... 71
A.1 Specifications 71
A.2 Recommended Replacement Parts List 72
A.3 Drawing List 73
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Trace Nitrogen in Argon Analyzer
List of Figures
Figure 1-1 Model 2120XL Front Panel 3
Figure 1-2: Model 2120XL Rear Panel 6
Figure 1-3: Internal Component Identification 7
Figure 3-1: Required Front Door Clearance 19
Figure 3-2: Rear Panel of the Model 2120XL 19
Figure 3-3: Equipment Interface Connector Pin Arrangement 21
Figure 3-4: Remote Valve Connections 25
Figure 3-5: FET Series Resistance 26
Figure 3-6: Suggested Sample System 29
Figure 4-1: Hierarchy of Functions and Sub Functions 39
Figure 5-1: Removing Fuse Block from Housing 66
Figure 5-2: Installing Fuses 67
Teledyne Analytical Instruments ix
Model 2120XL
List of Tables
Table 3-1: Analog Output Connections 21
Table 3-2: Alarm Relay Contact Pins 22
Table 3-3: Remote Calibration Connections 23
Table 3-4: Range ID Relay Connections 24
Table 3-5: Commands via RS-232 Input 26
Table 3-6: Required RS-232 Options 27
Table 5-1: Routine Maintenance Schedule 66
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Trace Nitrogen in Argon Analyzer
DANGER
COMBUSTIBLE GAS USAGE
This is a general purpose instrument designed for use in a
non-hazardous area. It is the customer's responsibility to
ensure safety especially when combustible gases are
present since the potential of gas leaks always exist.
Never introduce gases other than argon into the analyzer. If
explosive, flammable or corrosive gases or gas mixtures are
allowed to flow into the analyzer, fire or explosion can result.
WARNING
Sample gas introduced must be at or very close to
atmospheric pressure or damage to the detector will result.
To avoid serious injury, read all precautionary labels
attached to equipment, cylinders, containers, and boxes
prior to start-up.
Labels attached in appropriate areas of the analyzer warn
you of inherent hazards associated with the system. For
personal safety, read the labels and perform directed
precautions before handling the equipment.
The customer should ensure that the principles of operating
this equipment are well understood by the user. Misuse of
this product in any manner, tampering with its components,
or unauthorized substitution of any component may
adversely affect the safety of this instrument.
Since the use of this instrument is beyond the control of
Teledyne Analytical Instruments, referred as TAI, no
responsibility by TAI, its affiliates, and agents for damage or
injury from misuse or neglect of this equipment is implied or
assumed.
Teledyne Analytical Instruments xi
Model 2120XL
Teledyne Analytical Instruments xii
Trace Nitrogen in Argon Analyzer Introduction
Introduction
1.1 Overview
This manual describes installation, operation and maintenance for
the Model 2120XL Trace Nitrogen in Argon Gas Analyzer. Section 1
describes the analyzer in general terms and provides additional safety
information pertinent to the proper operation of the instrument.
The Teledyne Model 2120XL Trace Nitrogen in Argon Gas
Analyzer is a robust analytical tool for measuring trace amounts of
nitrogen in argon. Using precise optical filtering, single line emission
characteristic of nitrogen is produced with an intensity proportional to
the nitrogen concentration.
The Model 2120XL has three user programmable analysis ranges
extending from 0-1 ppm to 0-100 ppm with corresponding analog output
signals that are proportional to the concentration on the selected range.
The nitrogen concentration is displayed on the front panel and the
analog output signals are available at the rear panel. Digital
communication is achieved with a standard RS-232 serial port.
The system is easy to operate with all controls and indicators
accessible from the front panel. Digital flow control, two adjustable
concentration alarms, system alarm, self-diagnostics are just a few of the
many features included on the standard Model 2120XL instrument.
1.2 Typical Applications
The Model 2120XL Trace Nitrogen in Argon Gas Analyzer is used
in a wide range of applications including:
Air separation plants
Argon Purification Plants
Specialty Gas Laboratories
Specialty Steel Manufacturing
Gas Management/Monitoring Systems
Teledyne Analytical Instruments 1
Introduction Model 2120XL
Quality Control for Truck Fills & Gas Cylinders
Process Control
New Line Certification
Chemical Plants
Welding Gas Management
Semiconductor Manufacturing
1.3 Features
The Model 2120XL comes equipped with the following standard
features:
A 2-line alphanumeric vacuum fluorescent display (VFD)
screen, driven by microprocessor electronics that
continuously prompts and informs the operator.
High resolution, accurate readings of nitrogen content from
low ppm levels through 100 ppm in argon. Large, bright,
meter readout.
Advanced high frequency plasma generator produces stable
electroluminescent discharge with minimal heating yielding a
spectral emission characteristic of the gas mixture.
Custom low-noise optical filter for precise narrow band
selection and low optical interference.
Amplified optics circuit for stable nitrogen detection at low
ppb level.
Microprocessor based electronics: 8-bit CMOS
microprocessor with 32 kB RAM and 128 kB ROM.
Three user definable output ranges (from 0-1 ppm through 0-
100 ppm) allow best match to users process and equipment.
Auto Ranging allows analyzer to automatically select the
proper preset range for a given measurement. Manual
override allows the user to lock onto a specific range of
interest.
Two adjustable concentration alarms and a system failure
alarm.
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Trace Nitrogen in Argon Analyzer Introduction
Extensive self-diagnostic testing, at startup and on demand,
with continuous power-supply monitoring.
Two way RFI protection.
RS-232 serial digital port for use with a computer or other
digital communication device.
Four analog outputs: two for measurement (0–1 VDC and
isolated 4–20 mA DC) and two for range identification.
Convenient and versatile, steel, flush-panel or rack-
mountable case with slide-out electronics drawer.
1.4 Front Panel
Operator controls and displays are located on the front panel as
shown in Figure 1-1.
Figure 1-1 Model 2120XL Front Panel
The standard 2120XL Nitrogen in Argon Analyzer is panel
mounted designed for easy installation in a standard 19” instrument
rack. All user controls and displays accessible from the front panel.
The front panel has thirteen buttons for operating the analyzer, a
digital meter, and an alphanumeric vacuum fluorescent (VFD) display.
Teledyne Analytical Instruments 3
Introduction Model 2120XL
Function Keys:
Six touch-sensitive membrane switches are used to change the specific
function performed by the analyzer:
Analyze Perform analysis for nitrogen content in an argon
gas mixture.
System Perform system-related tasks (described in detail
in Chapter 4, Operation.).
Span Span calibrate the analyzer.
Zero Zero calibrate the analyzer.
Alarms Set the alarm setpoints and attributes.
Range Set up the 3 user definable ranges for the
instrument.
Data Entry Keys:
Six touch-sensitive membrane switches are used to input data to the
instrument via the alphanumeric VFD display:
◄► Select between functions currently displayed on
the VFD screen.
▲▼ Increment or decrement values of functions
currently displayed.
Enter Advances VFD display to the next screen in a
series or returns to the Analyze screen if none
remain.
Escape Backs VFD display to the previous screen in a
series or returns to the Analyze screen if none
remain also used to abort an entry.
Digital Meter Display:
The meter display is a Light Emitting Diode (LED) device that produces
large, bright, 7-segment numbers that are legible in any lighting. It
produces a continuous readout from 0-10,000 ppm. It is accurate across
all analysis ranges without the discontinuity inherent in analog range
switching.
Alphanumeric Interface Screen:
The VFD screen is an easy-to-use interface from operator to analyzer. It
displays values, options, and messages that give the operator immediate
feedback.
Teledyne Analytical Instruments 4
Trace Nitrogen in Argon Analyzer Introduction
Standby Button:
The Standby turns off the display and outputs, but circuitry is still
operating.
CAUTION: THE POWER CABLE MUST BE UNPLUGGED TO
FULLY DISCONNECT POWER FROM THE
INSTRUMENT. WHEN CHASSIS IS EXPOSED OR
WHEN ACCESS DOOR IS OPEN AND POWER
CABLE IS CONNECTED, USE EXTRA CARE TO
AVOID CONTACT WITH LIVE ELECTRICAL CIRCUITS
.
Access Door:
For access to internal components of the analyzer, the front panel swings
open when the latch in the upper right corner of the panel is pressed all
the way in with a narrow gauge tool. Accessing the main circuit board
requires unfastening rear panel screws and sliding the unit out of the
case.
1.5 Rear Panel
The rear panel, shown in Figure 1-2, contains the gas and electrical
connectors for external inlets and outlets. Some of those depicted are
optional and may not appear on your instrument. The connectors are
described briefly here and in detail in Chapter 3 Installation.
Power Connection Universal AC power source.
Digital I/O Analog Outputs:
0–1 VDC nitrogen concentration
plus 0-1 VDC range ID, and
isolated 4–20 mA DC nitrogen
concentration plus 4-20 mA DC
range ID.
Alarm Signals:
2 concentration alarms and 1
system alarm.
Remote Span/Zero
Digital inputs allow external
control of analyzer calibration.
Teledyne Analytical Instruments 5
Introduction Model 2120XL
Calibration Contact
Notifies external equipment that
instrument is being calibrated and
readings are not monitoring
sample.
Range ID Contacts
Four separate, dedicated, range
relay contacts. Low, Medium,
High, Cal (not used).
RS-232 Port Serial digital concentration signal
output and control input.
Gas Inlet and Outlet One inlet and one vent.
Purge Connections Inlet and outlet connections for
purging the analyzer.
Instrument Air Used for driving optional auto
calibration valves.
Figure 1-2: Model 2120XL Rear Panel
1.6 Internal Components
The internal components can be accessed by removing the top
cover of the analyzer. Figure 1-3 shows an inside view of the analyzer
Teledyne Analytical Instruments 6
Trace Nitrogen in Argon Analyzer Introduction
and identifies specific components of the analyzer. See also Figure 1-4
for internal components inside the card cage.
Figure 1-3: Internal Component Identification
WARNING: HIGH VOLTAGE. ELECTROCUTION HAZARD.
UNPLUG THE ANALYZER BEFORE REMOVING THE
COVER. THE OUTPUT OF THE HIGH-VOLTAGE
TRANSFORMER AND THE ANALYTICAL CELL
ELECTRODES CAN APPROACH VOLTAGES OF
10,000 VAC. THE ANALYZER SHOULD BE SERVICED
ONLY BY A QUALIFIED SERVICE TECHNICIAN.
1.7 Additional Safety Information
Note: The material provided in this section contains information
to promote safety in the operation and maintenance of this
equipment. It is not intended to supersede, replicate, or
replace any safety documentation or procedures provided
from or established by official safety sources.
Teledyne Analytical Instruments 7
Introduction Model 2120XL
Do NOT operate the Model 2120XL Trace Nitrogen in Argon
Gas Analyzer until you read and understand the operating,
maintenance, and safety instructions included in this
manual.
Anyone involved with the operation of this equipment
including plant engineering, operations, and management, must
understand the potential hazards involved, and know and observe all
required safety precautions.
Your safety and the safety of equipment, nearby facilities, and
personnel require a proper safety attitude and emphasis on safe work
procedures. This is the essence of any good safety program. If at any
time you identify safety deficiencies, immediately correct them and
bring them to the attention of management.
Before an accident can be prevented, it must be anticipated. Use
pre-job discussions with your coworkers and supervisors to identify
hazards and the means to avoid them. At your facility, various gases
may exist in liquid and/or gaseous states. Familiarize yourself with the
hazards associated with each gas found at your facility.
Read and understand the Material Safety Data Sheets (MSDS) for
the materials used with this equipment. All personnel who work in the
vicinity of this equipment should read, understand, and follow all safety
information contained in the MSDSs, in addition to following all
government and facility safety regulations.
CAUTION: NEVER INTRODUCE GASES OTHER THAN ARGON
INTO THE ANALYZER. IF EXPLOSIVE, FLAMMABLE,
OR CORROSIVE GASES OR GAS MIXTURES ARE
ALLOWED TO FLOW INTO THE ANALYZER, FIRE OR
EXPLOSION CAN RESULT. THIS ANALYZER IS NOT
DESIGNED TO BE USED IN HAZARDOUS AREAS.
1.7.1 Detector Cautions
The Model 2120XL uses a detection technique based on
spectroscopic emission. The detector is a thin-walled pure quartz cell
located in an electromagnetic field created by a specific high intensity
plasma generator. This electromagnetic field creates a plasma that emits
light at different wavelengths. A filter for the nitrogen is used to avoid
any interference and get the best performance.
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Trace Nitrogen in Argon Analyzer Introduction
Since the cell is made of thin quartz, this analyzer must be used at
atmospheric pressure to avoid cell damage. Any back pressure in the
detector will cause damage and require replacement of the module.
Make sure the vent is at atmospheric pressure and without
restrictions or blockage.
1.7.2 Basic Safety Requirements
The following safety guidelines apply at all times when working
with the Model 2120XL analyzer:
Prevent electrical shock — Unplug and remove the AC
power cord from the rear panel before opening and working on
the analyzer. Use tools designed for work on electrical
equipment.
Prevent injury — Always wear safety glasses and appropriate
safety protection. Ensure that all tools and instruments used
during installation and maintenance are in good condition. Be
aware that high-velocity gas may be released at vents and safety
relief valves.
Follow posted precautions — Read all precautionary labels
attached to the equipment. Be sure to read all cylinder labels and
warnings. Comply with all precautions before handling the
equipment.
Situations may develop for which no written procedures exist.
Think carefully before acting. Know the function of each valve and
switch, and its effect on the equipment. Carefully review all operating
procedures before starting up this equipment to ensure knowledge and
understanding.
1.7.3 Precautionary Labels
WARNING: TO AVOID SERIOUS INJURY, READ ALL CAUTION
LABELS ATTACHED TO EQUIPMENT, CYLINDERS,
CONTAINERS, AND BOXES PRIOR TO START-UP.
Labels attached in appropriate areas of the analyzer warn you of
inherent hazards associated with the system. For personal safety, read
the labels and perform directed instructions before handling the
equipment.
Teledyne Analytical Instruments 9
Introduction Model 2120XL
1.7.4 Summary of Known Hazards
This equipment is designed to minimize your exposure to the process
gases and other known hazards. Read and thoroughly understand all
safety aspects of this system and its operation before operating or
maintaining the equipment.
1.7.4.1 ELECTROCUTION
WARNING: DO NOT OPERATE THE ANALYZER WITHOUT THE
COVER SECURED IN PLACE. THE OUTPUT OF THE
HIGH-VOLTAGE TRANSFORMER AND THE
ANALYTICAL CELL ELECTRODES CAN APPROACH
VOLTAGES OF 6,000 VAC OR HIGHER. TO GUARD
AGAINST ELECTRICAL SHOCK AND POSSIBLE
ELECTROCUTION, THE ANALYZER SHOULD BE
SERVICED ONLY BY A QUALIFIED SERVICE
TECHNICIAN.
Adherence to the following guidelines helps guard against electrical
shock:
For safety and proper performance, this analyzer must be
connected to a properly grounded three-wire source of
electrical power.
Tampering or unauthorized substitution of components may
adversely affect the safety of this instrument. Use only
factory-approved components for repair.
Before checking or replacing any chassis component, turn off
the power and remove the AC power cord from the rear
panel.
1.7.4.2 PRESSURE
WARNING: MISHANDLING OF GAS CYLINDERS COULD
RESULT IN DEATH, SERIOUS INJURY, OR
PROPERTY DAMAGE. HANDLE AND STORE GAS
CYLINDERS WITH EXTREME CARE AND IN
ACCORDANCE WITH MANUFACTURER'S
INSTRUCTIONS.
Sudden or uncontrolled release of pressurized gas can cause serious
injury. The hazards of high pressure can be avoided through careful
inspection and handling of cylinders and equipment with proper
Teledyne Analytical Instruments 10
Trace Nitrogen in Argon Analyzer Introduction
regulation. Read and understand the MSDSs for the process gases used
before operating this analyzer. More detailed information on the
precautions and safe practices to follow when handling cylinders can be
found in the CGA pamphlet P-1, Safe Handling of Compressed Gases in
Cylinders.
1.7.4.3 PURGING
CAUTION: EQUIPMENT DAMAGE MAY RESULT IF THE
ANALYTICAL CELL IN THIS UNIT IS EXPOSED TO
PRESSURE ABOVE ATMOSPHERIC PRESSURE.
THE CELL MAY BREAK OR SHATTER. TO PREVENT
THIS, ALWAYS KEEP THE VENT AT ATMOSPHERIC
PRESSURE.
DO NOT EXCEED 20 PSIG (138 KPA) AT THE
SAMPLE INLET.
DO NOT BLOCK THE VENT.
Follow applicable safety precautions to ensure that an oxygendeficient atmosphere is not created in the work area. Use low parts per
million (ppm) nitrogen in argon gas with proper regulation to avoid
contaminating the sampling system.
1.7.4.4 SAFE REPAIR PROCEDURES
Any repair work must be performed by a qualified service
technician. Use only factory-approved components for repair.
Analyzer manifold purging as well as subsequent repair work must
be performed by experienced personnel.
Ventilate working area to prevent any leaking supply gas from
accumulating. Vent all gases to the outside.
Vent all pressure relief valves out of enclosed areas. Piping must be
properly sized to allow safety devices to operate according to
specifications.
De-pressurize supply gas piping before working on it.
1.7.4.5 GENERAL PRECAUTIONS FOR HANDLING AND STORING HIGH
PRESSURE GAS CYLINDERS
Compressed gases have properties that can cause serious accidents,
injuries, and even death if proper precautions and safety practices are
Teledyne Analytical Instruments 11
Introduction Model 2120XL
not followed. Therefore, during handling and use of these gases, be
certain to use applicable safety precautions described by your local
compressed gas supplier, the Compressed Gas Association, and/or
OSHA regulations.
1. Read the label on all cylinders BEFORE using to identify
the cylinder contents. If the label is illegible, return the
cylinder to the supplier. DO NOT ASSUME THE
CONTENTS.
2. Secure cylinders in storage and in use to an immovable
structure to prevent accidental falling or movement. Read
the relevant safety codes.
3. Store or move cylinders ONLY in the vertical position. DO
NOT move or transport cylinders with regulators attached.
4. Store cylinders in a well ventilated area away from heat or
ignition sources.
5. When installing tubing, provide ONLY approved, adequate
pressure reducing regulators and pressure relief devices to
prevent over-pressurizing of tubing and equipment.
6. Never drop cylinders or permit them to strike each other
violently.
7. Cylinders may be stored in the open but, in such cases,
should be protected against extremes of weather and from
damp ground (to prevent rusting) in areas where extreme
temperatures are prevalent, store cylinders in the shade.
8. The valve protection cap should be left on each cylinder
until cylinder has been secured against a wall or bench, or
placed in a cylinder stand and is ready for use.
9. Avoid dragging, rolling or sliding cylinders even for a short
distance. Move cylinders by using a suitable hand truck.
10. Never tamper with safety devices in valves or cylinders.
11. Do not store full and empty cylinders together. Serious
suck-back can occur when an empty cylinder is attached to a
pressurized system.
12. No part of a cylinder should be subjected to a temperature
higher than 52°C (125°F). Do not permit flame to come in
contact with any part of a compressed gas cylinder.
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Trace Nitrogen in Argon Analyzer Operational Theory
Operational Theory
2.1 The Analyzer
The Model 2120XL Trace Nitrogen in Argon Gas Analyzer is a
rack mounting self-contained unit for measuring trace amounts of
nitrogen in an argon gas stream.
A customer supplied sample system directs a stream of refined
argon to the instrument at a pressure between 4 and 20 psig (14-138
kPa). The process stream enters at a constant flow rate and passes
through a flow module containing a flow control valve and a mass flow
transducer. A gas conditioning unit is installed to remove particulates
from the incoming gas sample.
The gas is then fed to a quartz analytical cell where it is ionized in a
plasma discharge. The high energy within the plasma results in constant
collisions of ions and electrons and yields a characteristic emission
spectra intimately associated with the gas comprising the plasma.
The specific line energy is identified for nitrogen and a custom
blocking filter is selectively chosen and installed at the factory which is
tuned to remove all but the narrow energy associated with the nitrogen
emission peak. The light energy passing through the filter is focused on
a photon detector also tuned to respond to that wavelength. This
instrument can only be used for analyzing nitrogen in argon.
The photodetector produces a signal which is integrated and then
amplified. The resulting signal is digitized and processed by a
microprocessor and signal processing circuit. The results are displayed
on the instrument display as parts per million (ppm). An additional
digital to analog circuit transforms the signal back to analog form and
produces an output signal, typically 4-20 mA DC that is proportional to
the nitrogen concentration on the selected range.
The microprocessor circuit accepts input from the mass flow
transducer as well as the user interface. The analyzer software interprets
operator key presses and initiates the appropriate action as well as
sending signals to the displays for prompting the user for input or data
display.
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Operational Theory Model 2120XL
After analysis, the gas is returned to the gas flow module. A signal
is produced in the flow transducer that is used by the microprocessor to
control the flow control valve. From the flow control module, the gas
exits the analyzer at atmospheric pressure.
The superior accuracy of the Model 2120XL is achieved through
enhanced coupling of the plasma to the process and an advanced plasma
generator design. Through proper frequency and intensity control a
uniform, precisely located, and highly stable plasma discharge is
produced with minimum heat generation. The resulting emission spectra
is clear and distinct.
The Model 2120XL is fitted with custom optical filtering and an
optics system that is specifically designed to reduce interference. The
desired spectral line used for analysis is sharp and focused on the
detector.
The detector lifetime is enhanced using a “Duty Cycle Controlled
System” by reducing the coating inside the cell. This also results in an
increase in sensitivity.
2.2 Sample System
A suitable external sample system must be provided by the
customer. The external sample system delivers calibration or sample gas
to the analyzer at a suitable pressure.
The sample system may contain a molecular sieve type trap to
reduce moisture levels in the sample gas. Moisture produces a wellknown interference line in the spectrum close to that of nitrogen. It is
necessary to use moisture-free sample gas or install an efficient moisture
trap on the inlet.
Internally the Model 2120XL employs a flow control valve which
provides proper flow through the analyzer when the inlet pressure is
maintained between 4 to 20 psig. The proper flow rate should be
maintained around 100 ccm.
Teledyne Analytical Instruments 14
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