Dräger PIR 7000 Technical Handbook page 33

If required:
Attach splash guard to flowcell.
Always required::
Check system for sufficient gas-tightness.
If there are leaks, effluent gas may enter the measuring cuvette and lead to incorrect
measurements.
To protect the flowcell from dust and moisture:
Fit air filter in the connected gas supply system.
Cover flowcell connections with protective caps when not in use, or connect the inlet and
outlet e.g. with a hose connector.
Operation
Prior to commissioning perform a zero-point and span calibration of the gas transmitter.
Disable the alarm activation in the central device and/or start maintenance mode of gas
transmitter – see "Calibration", on page 57.
Connect test gas supply to inlet of flowcell.
Recommended flow rate: 0.5 to 1.0 l/min.
Make sure no escaped gas can reach the remaining open IR measuring cuvette!
— If test gas flows through flowcell, the gas transmitter generates an analogue output signal
corresponding to the concentration.
— All alarm settings should be checked or deactivated during the test.
After the functional test: Purge flowcell using dry air or nitrogen to secure the zero-point.
Theory of operation
— Depending on the optical cuvette length of flowcell, the signal generated by the test gas
can be calculated as follows (example for Dräger PIR 7000 type 334, measured gas
methane):
Display of concentration [% vol.] =
CAUTION
Test gas concentration [% vol.]
Conversion factor
Accessories
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