Calculation of thermowells in temperature measurement
In temperature measuring devices, thermowells form the interface between the sensing element and the process. They protect the actual probe while they themselves are exposed to thermal, chemical and mechanical stresses.
For the safe operation of temperature measurements with thermowells, the following must be observed:
Thermowells are placed in a state of spatial stress by static pressure. Bending and shear stresses are added when flow is applied.
Behind flow-loaded thermowells, vortices are periodically detached. However, this effect, which is required for vortex flow meters, also leads to undesired oscillations of the thermowell and thus to its destruction if the frequency of the vortices does not deviate significantly from the resonant frequency of the thermowell.
For strength calculations, all stresses are combined into one equivalent stress, which should have a safety factor > 1.7 with respect to the hot yield strength or the creep strength of the material.
The risk of a thermowell failure can be significantly reduced by calculating the stresses prior to design.
Resistance (RTD) temperature assembly for surface temperature measurement in industrial applications
Resistance (RTD) temperature assembly for surface temperature measurement on double-walled pipes or similar applications
Resistance (RTD) temperature assembly for standard applications or use in existing thermowells