Supplied in stainless steel AISI 316 (other materials upon request), thermowells are intended to protect thermometers and temperature sensors of high pressures, corrosive media, etc and also allows removing the instrument when the process is being carried out.
Two main thermowell types are available: the weld-in type is the economic type because of it contains weldings in the body, and the bar stock thermowell, specially indicated for high pressures and temperatures.
Special features such as stepped or tapered profile can be performed. Both types can be thread or flange connected in accordance to DIN standards or customer specifications. Special coatings PTFE and ceramic available for wetted parts. The diameter of the stem (or sensible element part) should be approx. 1 mm. less than the diameter of the thermowell hole in which the stem is to be fitted. Gaps greater than 0,5 mm. between hole and stem have negative effect on the heat transfer and lead to inaccuracies. In cases the gap cannot be avoided
the stem may be filled with suitable thermic oil.
When ordering, the following information should be observed: Instrument stem length and diameter (indicating if thread is included), connection thread, process hole diameter, material required and any special influencing variable (high pressure, etc).