Thermowell for Low fluid velocity

At low velocities, the risk of thermowell failure is minimal and does not usually require frequency calculations.

If the following criteria are met, the designer may elect to wave calculation requirements.

  • Maximum fluid velocity is less than 2.1 ft/sec. [0.46 M/s].
  • Wall thickness at “A” support diameter minus “b” bore diameter = 0.376" [9.55mm].
  • “L” Unsupported length = 24" [.61 M]
  • “A” support and “B” tip diameter = 0.5" [12.7 mm]
  • Thermowell material satisfies “S” maximum allowable working stress = 69 Mpa.
  • “Sf” fatigue endurance limit, in the high-cycle limit = 21 Mpa.
  • Thermowell material should not subject to stress corrosion or embrittlement.