Vaisala HMP230 User Manual
Page 25
HMP230 SERIES
M210225en-B
User's Guide
19
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STEP 3: push the probe head through the ball valve assembly into the
process. If the pressure is high, use a manual press tool. Note that the
sensor head must be pushed so deep that the filter is completely inside the
process flow.
VALVE OPEN
MANUAL
PRESS TOOL
VALVE CLOSED
FILTER
Figure 18 Installing the probe through the ball valve
assembly: step 3
For by-pass measurements, the probe is mounted behind the ball valve
assembly and non-leaking screw A on the fitting body is replaced with leaking
screw B and O-ring is placed on the groove of the sintered filter. Screw B has
a small (0.08 mm) laser-made hole in the middle; the gas or air to be measured
passes through the sintered filter and by the sensor, and leaks out through the
screw. The process pressure reduces in the hole of the screw B. This
installation is recommended if the process flow rate is >20 m/s and there is an
over-pressure in the process.