Alpha Moisture Systems DS1200-PDT, Руководство пользователя

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Model DS1200-PDT - Dewpoint Hygrometer
Piping Installation Schematic - Continued
1) Sample Isolation Valve - This is a recommended item as it allows access to the
sample system without interrupting the main process line.
2) Sample Tube – This should be stainless steel for dry air or gas applications but copper
or carbon steel can be used where wetter gases are to be measured. If any section of
the sample tube must be flexible then PTFE should be used. In most cases, 3mm OD
(1/8”) is sufficient as it provides good system response time within minimum flow.
6mm OD (1/4”) tube can be used where pressure drops across the 3mm tube are too
high.
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 – If the sample is to be measured at
atmospheric pressure then the valve 4A should be fitted and 4B omitted from the
system. If the sample is to be measured, at full line pressure and the exhaust vented
to atmosphere, then valve 4B should be fitted and 4A omitted from the system. If
measurements are to be taken at full line pressure and the sample is to be returned
to a part of the main line or a vent, which is at a pressure higher than atmospheric,
and the input to that line needs a controlled pressure then both 4A and 4B will
be required.
5) Sample Pressure Gauge – This is not a critical part of the moisture measurement
but may be required if Dew/Frost point measurements are to be made at higher
than atmospheric pressure.
6) Measuring Transmitter – Model PDT with Connector, General Arrangement.
7) Transmitter Holder – Transmitter Holder General Arrangement.
8) Desiccant Chamber – This item is required when the sampling is to be intermittent.
When installed it prevents the ingress of wet air to the sample system, while the
sample is not flowing, improving the response time.
9) Flow Control Valve – This can be a separate item or combined with the flow indicator.
10) Flow Indicator – The recommended minimum sample flow is 2 to 3 litres per minute.
11) Sample Exhaust – The exhaust can be vented to atmosphere or returned to the
process line as discussed above.
All additional components are available through your local distributor.