Sizing a THREADED Ashcroft thermowell with an Ashcroft
bimetallic thermometer.
Example without a lagging extension:
Requirement is for 4 ½ inch immersion into the process media.
This would be the “U” dimension.
Add the U dimension to the 1.75 inch dimension for the wrench
flats and process connection. This will equal the OAL (overall
length). The stem length of the thermometer will be a ¼ inch
shorter than the thermowell OAL.
“U” 4.50 + “Threads & wrench flats” 1.75 = OAL 6.25.
Stem length for bimetal thermometer = 6 inches
Example with a lagging extension:
Requirement is for 4 ½ inch immersion into the process media and
6” lagging extension.
Add the U dimension to the lag plus the 1.75 inch wrench flats and
process connection. 4.50 (U) + 6.00 (T) + 1.75 = 12.25 (OAL)
Bimetal thermometer stem length would equal 12 inches