Vaisala HMT360N - Manual (Page 29)

Chapter 3 _______________________________________________________________ Installation
VAISALA _______________________________________________________________________ 27
HMP364 for High-Pressure
Applications
The probe is provided with a nut, a fitting screw and a sealing washer.
Keep the fitting screw and the nut in place on the body of the probe
during handling to prevent damage to the highly polished surface of the
probe. Follow the instructions below to achieve a leak-tight assembly.
1. Remove the fitting screw from the nut and the probe.
2. Fasten the fitting screw to the chamber wall with a sealing washer.
Tighten the fitting screw into the threaded sleeve with a torque
spanner. The tightening torque is 150 ± 10 Nm (110 ± 7 ft-lbs).
3. Insert the body of the probe into the fitting screw and tighten the
nut manually to the fitting screw.
4. Mark both the fitting screw and the nut hex.
5. Tighten the nut a further 30º (1/12) turn or if you have a torque
spanner tighten it with a torque of 80 ± 10 Nm (60 ± 7 ft-lbs).
6. Clean and grease the tightening cone of the fitting screw after every
tenth detachment. Change the sealing washer every time the fitting
screw is detached. Use high-vacuum grease, for example Dow
Corning, or a similar grease.
CAUTION In pressurized processed it is essential to tighten the supporting nuts
and screws very carefully to prevent loosening of the probe by the
action of pressure.
NOTE When retightening the nut after detachment the nut must be tightened
without increased effort.