TVOC 2 MANUAL
Ion Science Ltd
Page 26 of 32
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System recommendations
For a gas sample system, we have the following recommendations:
1.
Where possible use the Flow Adaptor (as described above) that is sold by ISL. This has an integral O-ring to seal
the sensor housing and ports for connection of inlet and outlet sample tubes. Please refer to spare parts section
for part number.
2.
The pressure difference of a pumped system relative to atmosphere should be minimised to avoid the effects of
gas law.
3.
The maximum pressure that can be applied to the TVOC 2 sensor housing is 300 mbar. However, this is not a
recommended working pressure. Ideally working pressure should be +/- 30 mbar relative to ambient pressure.
4.
In line flow restrictions must be minimized. Flow restrictions cause differential pressures which can directly affect
the TVOC 2 reading. If flow restrictions are unavoidable the flow rate should be lowered to minimize the pressure
effects, this however will increase the response time.
5.
A flow between 250 and 500 ml/min is recommended for calibration. This will ensure a full response to applied
gas in a sensible time.
6.
The working flow should be very similar to that use to calibrate the instrument or errors in output will occur (see
point 2).
7.
The response time of the system is defined by the sensor response rate and sample flow rate will in combination
with the tube length and diameter as well as any dead volumes.
