Shaw SDHmini Bl, Инструкция по эксплуатации

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reading. The flow should not be so high that the gas velocity could physically
damage the sensor or cause back-pressure in the sensor head, so should not
exceed approximately 10 litres/min.
Allow this purge to continue for two 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.
4.1 Sampling Information
Refer to the
Piping Installation Schematic
in section 3.2.
The SDHmini sensor will respond to the water vapour pressure of a gas in
contact with it. It is important to ensure that the gas passing through the
sensor head is the same as the gas being sampled.
4.2 Sample Connections
The SDHmini is supplied with two connections: a “fir tree” on one side and a
Swagelok compression fitting for ¼”, ⅛”, or 6 mm OD pipe (as specified on your
order) on the other. Either can be used as the inlet connection (6).
PTFE and stainless steel are recommended materials for sample pipes. Some
specialist flexible tubing may be suitable as sample pipe but common flexible
tubing such as PVC, nylon, polythene or rubber, should not be used, as they are
permeable and water vapour from the atmosphere will diffuse through them
into the sample gas.
A 2 m PTFE sample pipe is supplied for use with the “fir tree” connection. The
first time this is used it is advisable to warm the end that will go over the “fir
tree” for a few seconds with a heat source to soften it slightly, which helps to
get a gas tight seal.
4.3 Sample Conditioning
The main principle when considering the presentation of the gas sample to the
SDHmini dewpoint meter is to keep the sample system as simple as possible
and of minimum swept volume, so that it has the least possible influence on
the gas sample.
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