Analytical Industries GPR-1000 User Manual

GPR-1000

Portable ppm Oxygen Analyzer

Owner’s Manual

2855 Metropolitan Place, Pomona, CA 91767 USA ♦ Tel: [phone], Fax: [phone], e-mail: [e-mail], www.aii2.com

2

Table of Contents

Introduction

1

Quality Control Certification

2

Safety

3

Features & Specifications

4

Operation

5

Maintenance

6

Spare Parts

7

Troubleshooting

8

Warranty

9

Material Safety Data Sheets

10

1 Introduction

Your new portable oxygen analyzer incorporates an advanced electrochemical sensor specific to oxygen along with
state-of-the-art digital electronics designed to give you years of reliable precise oxygen measurements in variety of
industrial oxygen applications. To obtain maximum performance from your new oxygen analyzer, please read and
follow the guidelines provided in this Owner’s Manual.

Every effort has been made to select the most reliable state of the art materials and components; and, to design
the analyzer for superior performance and minimal cost of ownership. This analyzer was tested thoroughly by the
manufacturer prior to shipment for best performance.

However, modern electronic devices do require service from time to time. The warranty included herein plus a staff
of trained professional technicians to quickly service your analyzer is your assurance that we stand behind every
analyzer sold.

The serial number of this analyzer may be found on the inside the analyzer. You should note the serial number in
the space provided and retains this Owner’s Manual as a permanent record of your purchase, for future reference
and for warranty considerations.

Serial Number: _______________________

Advanced Instruments Inc. appreciates your business and pledges to make every effort to maintain the highest
possible quality standards with respect to product design, manufacturing and service.

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2 Quality Control Certification

Date: Customer: Order No.: Pass
Model GPR-1000 Portable ppm Oxygen Analyzer
Sensor ( ) GPR-12-100-M ppm Oxygen Sensor

( ) XLT-12-100-M ppm Oxygen Sensor

Serial Nos. Analyzer_________________________ Sensor _____________________________
Accessories Owner’s Manual
( ) PWRS-1002 9VDC Battery Charger/Adapter 110VAC

( ) PWRS-1003 9VDC Battery Charger/Adapter 220VAC
( ) PWRS-1008 9VDC Battery Charger/Adapter 12VDC Auto Cigarette Lighter

CONN-1034 Plug Mini Phone .141 dia. Black Handle
FITN-1003 (3x) Plug Male Quick Disconnect Fittings
TOOL-1001 5/16 Combination Wrench
Configuration A-1151-E-B1 PCB Assembly
Range: 0-1000 ppm, 0-1%, 0-25%
Wetted parts: stainless steel

Electronics Test LED indicators: Low battery, charge
Electronic offset
Analog signal output 0-1V
Gas Phase Test Recovery from air to < 10 ppm in < 1 hour

Baseline drift on zero gas < ± 2% FS over 24 hour period on 0-1% range
Noise level < ± 0.5% FS

Span adjustment within 10-50% FS
Final Overall inspection for physical defects

Options
Notes

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3 Safety

General

This section summarizes the essential precautions applicable to the GPR-1000 Series Portable ppm Oxygen
Analyzer. Additional precautions specific to individual analyzer are contained in the following sections of this
manual. To operate the analyzer safely and obtain maximum performance follow the basic guidelines outlined in
this Owner’s Manual.

Caution: This symbol is used throughout the Owner’s Manual to CAUTION and alert the user to recommended
safety and/or operating guidelines.

Danger: This symbol is used throughout the Owner’s Manual to identify sources of immediate DANGER such as
the presence of hazardous voltages.

Read Instructions: Before operating the analyzer read the instructions.
Retain Instructions: The safety precautions and operating instructions found in the Owner’s Manual should be

retained for future reference.

Heed Warnings: Follow all warnings on the analyzer, accessories (if any) and in this Owner’s Manual.
Follow Instructions: Observe all precautions and operating instructions. Failure to do so may result in personal

injury or damage to the analyzer.

Installation

Oxygen Sensor: DO NOT open the sensor. The sensor contains a corrosive liquid electrolyte that could be
harmful if touched or ingested, refer to the Material Safety Data Sheet contained in the Owner’s Manual appendix.
Avoid contact with any liquid or crystal type powder in or around the sensor or sensor housing, as either could be a
form of electrolyte. Leaking sensors should be disposed of in accordance with local regulations.

Inlet Pressure: The analyzer is designed for flowing samples are intended to operate at positive pressure
regulated to between 5-30 psig.

Outlet Pressure: The sample gas vent pressure should be atmospheric.
Flow Rate: Recommended – 2 SCFH or 1 liter per minute.
Mounting: Mount as recommended by the manufacturer. The analyzer is approved for indoor or outdoor use.
Power: Supply power to the analyzer only as rated by the specification or markings on the analyzer enclosure. The

wiring that connects the analyzer to the power source should be installed in accordance with recognized electrical
standards and so they are not pinched particularly near the power source and the point where they attach to the
analyzer. Never yank wiring to remove it from an outlet or from the analyzer.

Operating Temperature: The maximum operating temperature is 45º C.
Heat: Situate and store the analyzer away from sources of heat.
Liquid and Object Entry: The analyzer should not be immersed in any liquid. Care should be taken so that

liquids are not spilled into and objects do not fall into the inside of the analyzer.
Handling: Do not use force when using the switches and knobs. Before moving your analyzer be sure to

disconnect the wiring/power cord and any cables connected to the output terminals located on the analyzer.

5

Maintenance

Serviceability: Except for replacing the oxygen sensor, there are no parts inside the analyzer for the operator to
service.

Only trained personnel with the authorization of their supervisor should conduct maintenance.
Oxygen Sensor: DO NOT open the sensor. The sensor contains a corrosive liquid electrolyte that could be

harmful if touched or ingested, refer to the Material Safety Data Sheet contained in the Owner’s Manual appendix.
Avoid contact with any liquid or crystal type powder in or around the sensor or sensor housing, as either could be a
form of electrolyte. Leaking sensors should be disposed of in accordance with local regulations.

Troubleshooting: Consult the guidelines in Section 8 for advice on the common operating errors before
concluding that your analyzer is faulty.

Do not attempt to service the analyzer beyond those means described in this Owner’s Manual. Do not attempt to
make repairs by yourself as this will void the warranty as per Section 10 and may result in electrical shock, injury or
damage. All other servicing should be referred to qualified service personnel.

Cleaning: The analyzer should be cleaned only as recommended by the manufacturer. Wipe off dust and dirt from
the outside of the unit with a soft damp cloth then dry immediately. Do not use solvents or chemicals.

Nonuse Periods: If the analyzer is equipped with a range switch advance the switch to the OFF position and
disconnect the power when the analyzer is left unused for a long period of time.

4 Features & Specifications

See last page, this page left blank intentionally.

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5 Operation

Principle of Operation

The GPR-1000 portable oxygen analyzer incorporates a variety of ppm range advanced galvanic fuel cell type
sensors. The analyzer is configured in a general purpose NEMA 4 rated enclosure. An integral sampling pump
options is available.

Advanced Galvanic Sensor Technology:

The sensors function on the same principle and are specific for oxygen. They measure the partial pressure of
oxygen from low ppm to 100% levels in inert gases, gaseous hydrocarbons, helium, hydrogen, mixed gases, acid
gas streams and ambient air. Oxygen, the fuel for this electrochemical transducer, diffusing into the sensor reacts
chemically at the sensing electrode to produce an electrical current output proportional to the oxygen concentration
in the gas phase. The sensor’s signal output is linear over all ranges and remains virtually constant over its useful
life. The sensor requires no maintenance and is easily and safely replaced at the end of its useful life.

Proprietary advancements in design and chemistry add significant advantages to an extremely versatile oxygen
sensing technology. Sensors for low ppm analysis recover from air to ppm levels in minutes, exhibit longer life and
reliable quality. The expected life of our new generation of percentage range sensors now range to five and ten
years with faster response times and greater stability. Another significant development involves expanding the
operating temperature range for percentage range sensors from -30°C to 50°C.

Electronics:

The signal generated by the sensor is processed by state of the art low power micro-processor based digital
circuitry. The first stage amplifies the signal. The second stage eliminates the low frequency noise. The third stage
employs a high frequency filter and compensates for signal output variations caused by ambient temperature
changes. The result is a very stable signal. Sample oxygen is analyzed very accurately. Response time of 90% of
full scale is less than 10 seconds (actual experience may vary due to the integrity of sample line connections, dead
volume and flow rate selected) on all ranges under ambient monitoring conditions. Sensitivity is typically 0.5% of
full scale low range. Oxygen readings may be recorded by an external device via the 0-1V signal output jack.

Power is supplied by an integral rechargeable lead acid battery which provides enough power to operate the
analyzer continuously for approximately 60 days. An LED located on the front panel provides a blinking 72 hour
warning to recharge the battery. A 9VAC adapter (positive pole located on the inside of the female connector) can
be used to recharge the battery from a convenience outlet. The analyzer is designed to be fully operational during
the 8-10 hour charging cycle which is indicated by a second continuously lit LED.

Sample System:

The GPR-1000 is supplied without a sample conditioning system for maximum portability. However the sample
must be properly presented to the sensor to ensure an accurate measurement. Users interested in adding their
own sample conditioning system should consult the factory. Advanced Instruments Inc. offers a full line of sample
handling, conditioning and expertise to meet your application requirements. Contact us at 909-392-6900 or e-mail
us at [e-mail]

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Pressure & Flow

All electrochemical oxygen sensors respond to partial pressure changes in oxygen. The inlet pressure must always
be higher than the pressure at the outlet vent which is normally at atmospheric pressure.

Flow Through Configuration:

The sensor is exposed to sample gas that must flow or be drawn through
metal tubing inside the analyzer. The GPR-1000 internal sample system
includes a quick disconnect female inlet fitting, a stainless steel sensor
housing with an o-ring seal to prevent the leakage of air and another quick
disconnect female vent fitting. Mating male quick disconnect fittings are
provided for introducing sample and calibration gases, a third male fitting
is provided for the vent line.

Flow rates of 1-5 SCFH cause no appreciable change in the oxygen
reading. However, flow rates above 5 SCFH generate backpressure and
erroneous oxygen readings because the diameter of the integral tubing
cannot evacuate the sample gas at the higher flow rate. The direction the
sample gas flows is not important, thus either female fitting can serve as
the inlet or vent – just not simultaneously.

A flow indicator with an integral metering valve upstream of the sensor is
recommended as a means of controlling the flow rate of the sample gas. A
flow rate of 2 SCFH or 1liter per minute is recommended for optimum
performance.

Caution: Do not place your finger over the vent (it pressurizes the sensor)
to test the flow indicator when gas is flowing to the sensor. Removing your
finger (the restriction) generates a vacuum on the sensor and may damage the sensor (voiding the sensor
warranty).

To avoid generating a vacuum on the sensor (as described above) during operation, always
select and install the vent fitting first and remove the vent fitting last.

Application Pressure - Positive:

A flow indicator with integral metering valve (GPR-1000M option) positioned upstream of the
sensor is recommended for controlling the sample flow rate between 1-5 SCFH.

If necessary, a pressure regulator (with a metallic diaphragm is recommended for optimum
accuracy, the use of diaphragms of more permeable materials may result in erroneous
readings) upstream of the flow control valve should be used to regulate the inlet pressure
between 5-30 psig.

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Application Pressure - Atmospheric or Slightly Negative:

For accurate ppm range oxygen measurements, an optional external sampling pump should be positioned
downstream of the sensor to draw the sample from the process, by the sensor and out to atmosphere. A flow
meter is generally not necessary to obtain the recommended flow rate with most sampling pumps, if the analyzer is
equipped with a flow meter make sure the valve is completely open to avoid drawing a vacuum on the sensor.

Caution: If the analyzer is equipped with an optional flow indicator with integral metering valve (GPR-1000M)
upstream of the sensor - open the metering valve completely to avoid drawing a vacuum on the sensor and placing
an undue burden on the pump.

If pump loading is a consideration, a second throttle valve on the pump’s inlet side may be necessary to provide a
bypass path so the sample flow rate is within the above parameters.

To avoid erroneous oxygen readings and damaging the sensor:

¾ Do not place your finger over the vent (it pressurizes the sensor) to test the flow indicator when gas is flowing

to the sensor. Removing your finger (the restriction) generates a vacuum on the sensor and may damage the
sensor (voiding the sensor warranty).

¾ Assure there are no restrictions in the sample or vent lines
¾ Avoid drawing a vacuum that exceeds 14” of water column pressure – unless done gradually
¾ Avoid excessive flow rates above 5 SCFH which generate backpressure on the sensor.
¾ Avoid sudden releases of backpressure that can severely damage the sensor.
¾ Avoid the collection of particulates, liquids or condensation collect on the sensor that could block the diffusion

of oxygen into the sensor.

9

Calibration & Accuracy

Single Point Calibration: As previously described the galvanic oxygen sensor generates an electrical current
sensor exhibiting an absolute zero, e.g. the sensor does not generate a current output in the absence of oxygen.
Given these linearity and absolute zero properties, single point calibration is possible.

Pressure: Because sensors are sensitive to the partial pressure of oxygen in the sample gas their output is a
function of the number of molecules of oxygen 'per unit volume'. Readouts in percent are permissible only when
the total pressure of the sample gas being analyzed remains constant. The pressure of the sample gas and that of
the calibration gas(es) must be the same (reality < 1-2 psi).

Temperature: The rate oxygen molecules diffuse into the sensor is controlled by a Teflon membrane otherwise
known as an 'oxygen diffusion limiting
barrier' and all diffusion processes are
temperature sensitive, the fact the
sensor's electrical output will vary with
temperature is normal. This variation is
relatively constant 2.5% per ºC. A
temperature compensation circuit
employing a thermistor offsets this
effect with an accuracy of +5% or
better and generates an output
function that is independent of
temperature. There is no error if the
calibration and sampling are
performed at the same temperature or if
the measurement is made immediately after calibration. Lastly, small temperature variations of 10-15º produce <
+1% error.

Accuracy:

In light of the above parameters, the overall accuracy of an analyzer is affected by two types of

errors: 1) those producing 'percent of reading errors', illustrated by Graph A below, such as +

5% temperature

compensation

circuit, tolerances of range resistors and the 'play' in the potentiometer used to make span

adjustments and 2) those producing 'percent of full scale errors', illustrated by Graph B, such as +1-2% linearity
errors in readout devices, which are really minimal due to today's technology and the fact that other errors are
'spanned out' during calibration.

Graph C illustrates these 'worse case' specifications that are typically used to develop an analyzer's overall accuracy
statement of +2% of full scale at constant temperature or +5% over the operating temperature range. QC testing
is typically <+0.5% prior to shipment.

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Example: As illustrated by Graph A any error, play in the multi-turn span pot or the temperature compensation
circuit, during a span adjustment at 20.9% (air) of full scale range would be multiplied by a factor of 4.78
(100/20.9) if used for measurements of 95-100% oxygen concentrations. Conversely, an error during a span
adjustment at 100% of full scale range is reduced proportionately for measurements of lower oxygen
concentrations.

Recommendation: Calibrating with a span gas approximating 80% of the full scale range one or two ranges
higher than the full scale range of interest is recommended for 'optimum calibration accuracy'.

Start-up

The GPR-1000 Portable ppm Oxygen Analyzer is fully operational from the shipping container with the oxygen
sensor installed and calibrated at the factory prior to shipment. Once installed, we recommend the user allow the
analyzer to stabilize for 30 minutes and then recalibrate the device as instructed below.

Assemble the necessary hardware for mounting the analyzer and optional components - such as coalescing or
particulate filters and pumps, 1/8” metal or plastic tubing for interconnecting the analyzer and optional
components.

Review the application conditions to ensure the sample is suitable for analysis.

1. Temperature: The sample must be sufficiently cooled before it enters the analyzer and any optional
components. A coiled 10 foot length of ¼” stainless steel tubing is sufficient for cooling sample gases as high
as 1,800ºF to ambient.

2. Pressure & Flow: As described above.

3. Moisture & Particulates: Prevent water and/or particulates from entering the sample system. They can clog
the tubing and damage the optional components such as pumps, scrubbers or sensors. Installation of a
suitable coalescing or particulate filter is required to remove condensation, moisture and/or particulates from
the sample gas to prevent erroneous analysis readings and damage to the sensor or optional components.
Consult the factory for recommendations concerning the proper selection and installation of components.

4. Contaminants: A gas scrubber and flow indicator with integral metering valve are required upstream of the
analyzer to remove interfering gases such as oxides of sulfur and nitrogen or hydrogen sulfide that can
produce false readings and reduce the expected life of the sensor. Installation of a suitable scrubber is required
to remove the contaminant from the sample gas to prevent erroneous analysis readings and damage to the
sensor or optional components. Consult the factory for recommendations concerning the proper selection and
installation of components.

5. Gas connections: Inlet and outlet vent gas lines require 1/8” diameter tubing preferably metal.

6. Power connection: Locate a source of AC power to meet area classification and to plug in the charging adapter.

7. Zero calibration (required only for very low percentage range measurements).

8. Span calibration – User s are responsible for certified span gas cylinder, regulator and flow control valve.

Mounting the Analyzer:

Normally mounting a portable analyzer is not a consideration. However, the GPR-1000 analyzer can operate
continuously when connected to AC power using the appropriate charging adapter. The analyzer enclosure is cast
with four (4) holes in the bottom section specifically intended for wall mounting.