Analytical Industries GPR-3100 Series Oxygen Purity Analyzer - Manual (Page 16)

Advanced Instruments Inc.
5 Operation
GPR-3100 Rev 2/05 9
Gas Connections:
The GPR-3100 is designed for positive pressure samples and requires connections for incoming sample
and vent lines. Optional zero and span inlet ports are provided as part of the optional sample systems.
Optional Span and Zero Inlet Ports Standard Sample and Vent Ports
The user is responsible for making provision for introducing gases for calibration purposes. 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. 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 1 liter 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).