Pipe Size for Thermowell
Pipe Size for Thermowell
(OP)
why in natural gas sytems (say 98% methane 30 barg 5000 kg/h 50C) does there seem to be an engieering standard for 4inch line size for thermowells, thermowells with RTD or T/C conected back to a transmitter only measure at the tip so why cant the line size be 2 or 3inch?





RE: Pipe Size for Thermowell
Instrumentation is not my expertise but I've worked for some time in the petrochemical industry and all company standards I've seen have called for thermowells in a minimum of 4" pipe line size. I believe this is related to the area of sensitivity of the measuring device and to help ensure there is no "outside" effect on the measurement.
Look at the "Insertion Length—The Accuracy Factor" in the following link...
http:
I would be curious to know if anyone knows of other reasons.
RE: Pipe Size for Thermowell
RE: Pipe Size for Thermowell
I am a bit fuzzy on your question. Are you asking:
a) why are thermo wells used on 4" lines and larger, or
b) why are the thermowells themselves in a 4" pipe/nozzle going into a pipe/vessel
RE: Pipe Size for Thermowell
John
RE: Pipe Size for Thermowell