Analytical Industries GPR-1800 IS ATEX Trace PPM Oxygen Transmitter - Manual (Page 33)

Advanced Instruments, Inc
33
For sample gases under positive pressure, the user must provide a means of controlling the inlet pressure
between 5-30 psig and the flow of the sample gas between 1-5 SCFH, a flow rate of 1-2 SCHF is
recommended
For sample gases under atmospheric or slightly negative pressure, an optional sampling pump is
recommended to push the sample the sensor housing. Generally, when using a pump, no pressure
regulation or flow control device is involved. However, a flow meter upstream of analyzer is recommended to
ensure that the sample flow is adequate.
Assure the sample is adequately vented for optimum response and recovery – and safety.
Allow the oxygen reading to stabilize for approximately 10 minutes at each sample point.
Note: To avoid erroneous oxygen readings and damage to the sensor, 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).
Assure there are no restrictions in the sample or vent lines
Avoid drawing a vacuum that exceeds 14” of water column pressure – unless done gradually
Avoid excessive flow rates above 5 SCFH which may generate backpressure on the sensor.
Avoid sudden releases of backpressure that can severely damage the sensor.
Avoid the collection of particulates, liquids or condensation on the sensor that could block the diffusion of
oxygen into the sensor.
If the transmitter is equipped with an optional integral sampling pump (positioned downstream of the sensor)
and a flow control metering valve (positioned upstream of the sensor), completely open the flow control
metering valve to avoid drawing a vacuum on the sensor and placing an undue burden on the pump
Standby
The transmitter has no special storage requirements.
The sensor should remain inside of the sensor housing and connected to the electronics during storage
periods. Before turning the sample gas OFF, ensure that sample/bypass valve (if analyzer equipped) is at
the BYPASS position. This will keep the sensor isolated from ambient air and would be ready to use again
when required with very short down time.
NOTE: Under isolated conditions, some oxygen will diffuse into the sample system/sensor housing and the
sensor out will slowly climb up but after 2-3 hours, it will reach a Plato, generally less than 400 PPM
Store the transmitter with the power OFF at a safe location and away from a direct heating source.
If storing for an extended period of time, protect the analyzer from dust, heat and moisture.