Attaching HMP374 to process - HMT370EX

HMT370EX User Guide

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User guide
Figure 1. HMP374 fitting body and clasp nut
Clasp nut
Fitting screw, M22×1.5 or NPT 1/2"
Sealing washer
To attach the probe to the process:
  1. Detach the fitting screw from the nut and slide it off the probe body.
  2. Attach the fitting screw to the chamber wall with a sealing washer. Tighten the fitting screw into the threaded sleeve with a torque wrench. The tightening torque is 150 ± 10 Nm (110 ± 7 ft-lbs).
  3. Insert the body of the probe into the fitting screw and attach the nut manually to the fitting screw so that the connection feels tight.
  4. Mark both the fitting screw and the nut hex.
  5. Tighten the nut a further 30° (1/12) turn, or if you have a torque wrench tighten it with a torque of 80 ± 10 Nm (60 ± 7 ft-lbs).
    Draw a line on the clasp nut and the fitting screw to mark the 30° (1/12) turn tightening rotation.
    When re-tightening the nut after detachment the nut must be tightened without increased effort.
  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 similar grease.
CAUTION In pressurized processes it is essential to tighten the probe very carefully when installing to prevent the loosening of the probe by the action of pressure.
CAUTION When HMP374 is installed in a process with a pressure differing from normal atmospheric pressure, you must enter the pressure value of the process as an environmental compensation in order to receive accurate measurement results. For information on entering environmental compensations with the transmitter display interface or Vaisala Insight PC software, see Environmental compensation and measurement settings overview.
Take care not to overtighten the clasp nut to avoid difficulties when opening it.