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3.
Filter Unit – A filter unit is recommended when the samples are likely to contain
particulate matter. If the air/gas sample contains heavy hydrocarbon condensate, the
filter must be of the coalescing type with a drain. The filter unit should be positioned as
close to the sample point as practical.
4.
Pressure Reduction Valve or Pressure Regulator – the sample is measured at
atmospheric pressure requiring that valve 4 is fitted to the system.
5.
Flow Control Valve.
6.
Sample Connection
7.
SADPminiEx.
8.
Flow Indicator – The recommended sample flow is 5 to 20 L/M.
9.
Sample Exhaust – The exhaust is vented to atmosphere or returned to an atmospheric
pressure line.
5
Purging the sample connection
Refer to the sample system schematic in section 4.2.
It is advisable to carry out an initial purge of the sample loop, before connecting the
SADPminiEx, in order to avoid the possibility of sensor damage on start-up.
Open the sample isolation valve (1) slowly, until a there is a small flow of air/gas at
atmospheric pressure from the pressure reduction valve (4) into SADPminiEx line. Allow
the air/gas to exhaust through the sample connection (9).
The SADPminiEx is not flow sensitive however the sample flow needs to be enough to
purge the sensor head effectively, so anything less than 1 litre/min would mean that the
instrument would take too long to settle to a stable reading. The flow should also not be so
high that the gas velocity could physically damage the sensor or cause backpressure in the
sensor head, so should not exceed about 20 litres/min.
Allow this purge to continue for 2 minutes to remove any residual moisture from the sample
pipe work and components. Check that no liquid or particulate contamination, which could
damage the sensor, is passing through the sample pipe. Directing the sample onto a piece
of white paper (such as a filter paper) will make it easier to see any dust or oil mist in the
sample.
6
Using the SADPminiEx to take a Moisture Reading
Refer to the sample system schematic in section 4.2.
The first purpose of the SADPminiEx is to provide a rapid, easy and reliable means of
carrying out moisture content measurements, of gases. To ensure rapid response the
sensor is kept dry by surrounding the sensor with desiccant in the head assembly when it is
not in use.
