Analytical Industries GPR-3500 MO Portable Oxygen Analyzer - Manual (Page 14)

Advanced Instruments Inc.
14
Span Gas Preparation
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.
Medical grade oxygen:
The FDA requires the use of certified gases for zeroing and calibrating analyzers used in certifying medical grade oxygen. Advanced
Instruments Inc. recommends zeroing and calibrating the analyzer before each certification.
The analyzer zero gas must be a certified cylinder of nitrogen with a minimum purity of 99.9%. Once the analyzer has been zeroed
(described below), calibrate (described below) with a certified cylinder of oxygen with a minimum purity of 99.2%.
Non-medical grade oxygen applications:
In non-medical grade oxygen applications the analyzer does not require zeroing before every calibration. It is recommended the
analyzer be calibrated at least monthly. In most cases nitrogen zero gas of 99% minimum purity and a span gas of 95-100% oxygen
purity is sufficient.
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 2 lengths of 1/8” dia. metal tubing measuring 4-6 ft. in length.
¾ Suitable fittings and 1/8” dia. metal tubing to connect the regulator to the flow meter inlet
¾ Suitable fitting and 1/8” dia. metal tubing to connect from the flow meter vent to tube fitting designated SAMPLE IN on the GPR-
1200.
Procedure:
1. With the span gas cylinder valve closed, install the regulator on the cylinder.
2. Open the regulator’s exit valve and partially open the pressure regulator’s control knob.
3. Open slightly the cylinder valve.
4. Loosen the nut connecting the regulator to the cylinder and bleed the pressure regulator.
5. Retighten the nut connecting the regulator to the cylinder
6. Adjust the regulator exit valve and slowly bleed the pressure regulator.
7. Open the cylinder valve completely.
8. Set the pressure between 5-30 psig using the pressure regulator’s control knob.
9. Caution: Do not exceed the recommended flow rate. Excessive flow rate could cause the backpressure on the sensor and may
result in erroneous readings and permanent damage to the sensor.
Establishing Power to the Electronics
Establish power to the analyzer electronics by pushing the red ON/OFF key. The digital display
responds instantaneously. When power is applied, the analyzer performs several diagnostic
system status checks termed “START-UP TEST” as illustrated below.
The optional integral sampling pump is activated by a separate toggle switch located on the
front of the analyzer.
Note: In the unlikely event the LED warning indicator LOW BATT comes on when the
analyzer is turned on – proceed immediately to the section Battery Considerations at the end
of section 5 Operation.
Note: The GPR-3500MO is supplied with an adapter for recharging the batteries or operating
the analyzer continuously.