Definition - What does Thermowell mean?
Thermowell is the most uncomplicated devices used for measurement of temperature. It is tubular fitting used to protect the temperature sensor which is installed in an industrial processor. It is a pressure tight receptacle tube that is designed to accept a temperature sensing element and provide a means to insert that element into a vessel or pipe. It is mainly used to measure the temperature of a moving fluid in a conduit, where the stream exerts an appreciable force.
Petropedia explains Thermowell
A thermowell is a cylindrical structure that is closed at one end and mounted in the process stream. The temperature sensor is inserted into the tube from the open end which is in the open air outside the process piping or vessel. The process fluid transfers heat through the walls of thermowell, which later transfer the heat to the temperature sensor. It is constructed by solid drilled-out bar stock and it is designed to protect a temperature sensor from high pressure, flow and harsh environment. In case the sensor fails, it can be easily replaced with draining the vessel or piping.