Analytical Industries GPR-1500 A Series Trace PPM Oxygen Analyzer - Manual (Page 20)

Advanced Instruments, Inc
20
Span Gas Preparation
Note: The GPR-1500-A transmitter can be calibrated by using ambient air. However, it can also be
calibrated by using a certified span gas. Air calibration can be achieved right after installing the sensor in the
housing. Subsequent calibration, where the sensor has been exposed to a sample gas, air calibration can
be achieved by either removing the sensor from the sensor housing or by pushing the air through the sensor
housing.
Caution: Do not contaminate the span gas cylinder when installing the pressure regulator on the
span gas cylinder. Further, bleed the air filled regulator and span gas tubing before connecting
the span gas to the analyzer and attempting the initial calibration.
Required Components
1. Certified span gas cylinder with an oxygen concentration, balance nitrogen, approximating 80% of the
full scale of the measuring range or one range above the intended measuring range.
2. A pressure regulator to set the span gas pressure between 5 and 30 psig.
3. A flow meter to set the flow between 1-5 SCFH.
4. Suitable tube fittings and a 4-6 ft. length of 1/8” dia. metal tubing to connect the regulator to the flow
meter inlet (flow meter supplied by the user).
5. Suitable tube fittings and a 4-6 ft. length of 1/8” dia. metal tubing to connect from the flow meter vent to
tube fitting of the sensor housing.
Procedure
1. With the span gas cylinder valve closed, install the pressure 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.
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 damage to the sensor