Advanced Instruments, Inc
Span Gas Preparation
See Section 4 – Features and Specifications, for exclusions
Note:
The GPR-1500 AIS 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
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
designated as SAMPLE IN or SPAN IN at the analyzer.
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 the sensor
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