Thermowell dimension and well material shall be specified on datasheet and surface finish shall be manufacturer’s standard.
Tolerances are as follows:
- Bore, “d” shall be 0.26 inch maximum to pass plug gauge of 0.254 inch OD.
- Bore /OD eccentricity shall be +/- 10 percent of minimum wall thickness.
- Bore depth shall be +/- 1/32 inch for depths to 30 inches.
- Overall length, “L” shall be +/- 1/32 inch for lengths to 30 inches.
- Insertion Length, “U” shall be +/- 1/16 inch for lengths to 12 inches and +/- 1/8 inch for lengths over 12 inches.
- Head diameter shall be +/- 0.01 inch
- Shank diameter shall be +/- 0.01 inch
- Tip diameter shall be +/- 1/32 inch
- Tip thickness +/- 1/32 inch
- 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.