Vaisala HUMICAP DMT132, User Manual

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3. Installation
3.1 Selecting Location
It is important that the conditions at the point of installation represent well the gas to be
measured. Temperature changes do not affect the dew point measurement, but pressure
changes will have an effect on dew point. All leaks in the system must be eliminated to avoid
ambient humidity affecting the measurement.
Direct installation to the measured gas is the recommended installation method if the
temperature of the gas is suitable for DMT132 and no additional filtering is needed due to
very dusty or oily gas. Oil as such is not harmful for the HUMICAP
â
sensor, but response
time may be slower if there are oil particles in the system, or if oil is collected to the filter
over a longer period of time. The maximum measurement pressure is 20 bar
a
/ 290 psi
a
(absolute pressure) for direct measurement.
If the gas temperature is higher than the specified maximum operating temperature of the
transmitter, gas sampling and cooling it to ambient temperature (for example, 20 °C / 68 °F)
is recommended. Note that the dew point temperature must be clearly lower than the
ambient temperature to avoid condensation in the sampling line. Sampling from the process
is easy by using Vaisala sampling cell options.
The DMT132 is light in weight, which means that it can be installed in a sample pipeline in the
sampling cells without the need for any additional mechanical support.
More Information
‣
Sampling Accessories for DMT132 (page 21)
Chapter 3 – Installation
15