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計測機器 Alpha Moisture Systems dewSMART DT20のPDF 取扱説明書をオンラインで閲覧またはダウンロードできます。Alpha Moisture Systems dewSMART DT20 15 ページ。 Dewpoint meter

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Page 5

INSTALLING THE AIR/GAS SAMPLING SYSTEM

The piping installation schematic diagram on page 6 of this manual, shows all

components which could be used in a dry gas measurement application although all the

items shown will not be required for every installation.

Care should be taken to ensure that the sample presented to the measuring sensor is not

contaminated with any component that will damage, contaminate or affect the sensor in a

way that will impair the system accuracy.

It is strongly recommended that the sample should not contain particulate matter, oil or

other heavy hydrocarbon condensate.

If these components contaminate the sample

system and/or the measuring sensor the system response time will be lengthened,

although the sensor calibration will not be effected.

The sample must not contain Ammonia, Chlorine, Ozone or any wet acid vapours or

liquid as these will permanently

damage the sensor and impair calibration accuracy.

The flow rate, although not critical to the sensor measurement, should be low enough to

avoid abrasion to the sensor surface without being so low as to extend the system

response time to an unacceptable level. In general, a flow rate of between 2 and 3

litres/min at NTP will give the light balance.

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The sensor is a variable capacitor which is directly affected by changes in partial pressure

of water vapour and these changes, which are proportional to the dew/frost point

temperature, are displayed on the instrument indicator.

Partial pressure of water vapour is directly affected by total pressure and, this being the

case, the instrument will display the dew/frost point temperature at whatever total

pressure the sensor is exposed, therefore care should be taken to ensure that the sample

pressure, at the sensor is that at whkh the dew/frost point readings are required.

The measuring sensor can be installed directly into the process line but this does create

problems with access for maintenance and calibration.

It is for these reasons that we

recommend that the sensor be installed in a bypass, fast loop or total loss sample system

where the sensor is accessible without interrupting the main process flow line.

NOTE

Do not install the sensor at this time. Wait until the commissioning stage,

as described on page 9.

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