Analytical Industries GPR-1900 Series Trace PPB Oxygen Analyzer - Manual (Page 15)

Advanced Instruments Inc.
15
Installing the Oxygen Sensor
The GPR-1900 Oxygen Analyzer is equipped with an external oxygen sensor. They have been tested and calibrated by the
manufacturer prior to shipment and are fully operational from the shipping containers. The sensor has not been installed at the
factory and it will be necessary to install the sensor in the field. Caution: Review procedure before proceeding, mainly 2 and 9.
Caution: DO NOT open the oxygen 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 manner similar to that of a common battery in accordance with local regulations.
Procedure:
1. The sensor has not been installed at the factory (in standard configuration there are no valves to isolate the sensor) and it
will be necessary to install the sensor in the field.
2. As described above the following steps should already be completed:
a) Secure the sensor housing bracket with two 6/32 mounting screws, in the preferred
position the upper section with the interconnection cable should be facing the ceiling;
b) connect the gas lines;
c) electrical connections.
1. Caution: Do not change the factory settings until instructed to do in this manual.
2. Purge the oxygen trapped in the newly connected gas lines for 3-5 minutes.
3. Flow zero gas or sample gas with a low ppm oxygen concentration to the analyzer at the
predetermined flow rate of 2 SCFH.
4. Using the 5/16 wrench supplied loosen but do not remove the clamp bolt located under the sensor housing, see photo.
5. Rotate the upper section of the sensor housing 90º to disengage from the clamp.
6. Remove the upper section by pulling it straight up and place it on a smooth surface.
7. Select the AUTO RANGING option from the SAMPLE menu with gas flowing to the analyzer.
8. Remove the oxygen sensor from the bag and remove the red shorting device (including the gold ribbon) from the PCB
located at the rear of the sensor.
9. Minimize the time the sensor is exposed to ambient air.
10. Immediately place the sensor in the bottom section of the sensor housing with the PCB facing up.
11. Immediately place the upper section of the sensor housing over the sensor, gently push the upper section downward and
rotate 90º to engage the clamp.
12. Finger tighten the clamp bolt and then tighten it one full turn with the 5/16 wrench to securely lock the two sections of the
sensor housing.
13. The analyzer will OVER RANGE for a short period of time as indicated by the graphical LCD display.
14. Wait until the display shows a meaningful oxygen reading and begins to approach the expected oxygen content of the
sample gas.
Span Gas Preparation
A percent analyzer such as the GPR-1900 may be reliable calibrated with the known 20.9% oxygen content of ambient air and
operated confidently at the lowest levels of the most sensitive analysis range. However, the GPR-1900 may be calibrated with
span gas at the user’s discretion.
Caution: Do not contaminate the span gas cylinder when connecting the regulator. Bleed the air filled regulator (faster and
more reliable than simply flowing the span gas) before attempting the initial calibration of the instrument.
Required components:
¾ Certified span gas cylinder with an oxygen concentration, balance nitrogen, approximating 80% of the full scale range
above the intended measuring range.
¾ Regulator to reduce pressure to between 5 and 30 psig.
¾ Flow meter to set the flow between 1-5 SCFH,
¾ Suitable fittings and 1/8” dia. 4-6 ft. in length of metal tubing to connect the regulator to the flow meter inlet
¾ Suitable fitting and 1/8” dia. 4-6 ft. in length of metal tubing to connect from the flow meter vent to tube fitting designated
SAMPLE IN on the GPR-1900.