Vaisala DMT340 - Manual (Page 52)

User's Guide _______________________________________________________________________
50 ___________________________________________________________________ M210704EN-G
An overpressure in the process is necessary to create a flow through the
sampling cell. Note that the pressure of the sampling cell must not differ
from that of the process because dewpoint temperature changes with
pressure. In dirty processes, it may be necessary to use a filter between
the cooling coil and the sampling cell. One more simple way of using the
sampling cell with user provided accessories is shown in the figure
below.The flow through the sampling cell is controlled with the needle
valve and the pressure is kept equal to that of the process.
0503-022
Figure 35 Installing the Probe in High Temperatures