Thermowell points to be taken care

Instrumentation Temperature
1

Thermowell dimension and well material shall be specified on datasheet and surface finish shall be manufacturer’s standard.

Thermowell points

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Tolerances are as follows:

  1. Bore, “d” shall be 0.26 inch maximum to pass plug gauge of 0.254 inch OD.
  2. Bore /OD eccentricity shall be +/- 10 percent of minimum wall thickness.
  3. Bore depth shall be +/- 1/32 inch for depths to 30 inches.
  4. Overall length, “L” shall be +/- 1/32 inch for lengths to 30 inches.
  5. Insertion Length, “U” shall be +/- 1/16 inch for lengths to 12 inches and +/- 1/8 inch for lengths over 12 inches.
  6. Head diameter shall be +/- 0.01 inch
  7. Shank diameter shall be +/- 0.01 inch
  8. Tip diameter shall be +/- 1/32 inch
  9. Tip thickness +/- 1/32 inch
  10. Thermowells shall have the tag number and material on the well head. For test thermowells, provide 1/2-inch NPT brass plug with brass chain attached to head of well by non-welding technique. Bore drilling may be performed either by twist drill or gun drill.