OMGEMN1.41
GEM2000 Range Gas Analysers
Page 48
Copyright 2009 Geotechnical Instruments (UK) Limited
7.10 Taking Gas and Flow Measurement Processes – Best Practice
Tips When Taking a Measurement:
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A prompt is displayed to ensure all tubes are disconnected, as a clean air purge will
automatically be carried out at this point to ensure the previous sample is purged
from the analyser.
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The Borehole ID number selected and the run-time are displayed in the upper left
corner of the ‘Main Gas Read Screen’.
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When attaching fittings to the connector ports ensure that they click in to place.
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As soon as a connection is made the relative pressure reading will be displayed.
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The pump will run for a pre-programmed time and a countdown timer will be
displayed. The pump may be stopped and started at any time. Whilst the pump is
running the analyser continuously monitors the peak readings.
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Pre-programmed questions may require numeric, alphanumeric, selectable comment
or exclusive comment.
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For ‘No ID’ readings the ID code information will be stored as ‘ ---------‘.
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The following information will be stored for each reading:
ID Code
Current time/date
Technician ID code
Site Data (if entered)
All gas readings and balance
Approximate hydrogen levels (Plus)
Peak CH
4
Peak CO
2
and Minimum O
2
(Plus)
LEL CH
4
or residual nitrogen N
2
Barometric pressure
Relative pressure
Borehole specific questions and comments
Temperature (optional)
External gas pod (optional)
Anemometer (optional)
The following process diagrams outline the recommended best practice steps when taking
gas and flow measurement readings.
