Vaisala DMT152 - Manual (Page 17)

Chapter 4 ________________________________________________________________ Installation
VAISALA ________________________________________________________________________ 15
CHAPTER 4
INSTALLATION
This chapter provides you with information that helps you install the
Dewpoint Transmitter DMT152.
Selecting the 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
dewpoint measurement, but pressure changes will have an effect on the
measurement. 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 DMT152 and no
additional filtering is needed due to very dusty or oily gas. Oil as such is
not harmful for the DRYCAP
®
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
50 bar
a
/ 725 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, 10 °C / 18 °F) is recommended. Note that the
dewpoint 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; see section
Sampling Accessories on page 24.
The DMT152 is light in weight, which means that it can be installed in a
sample pipeline in the sampling cells without the need of any additional
mechanical support.