Thermowells
Thermowells protect temperature sensors, including RTDs and thermocouples, during the monitoring process. They also have the ability to repair the sensors without having to remove the sensing element. The two basic kinds of thermowells are low pressure and high pressure thermowells.
Thermowells are closed-end tubes that are available in three different designs. Straight shank designs, which have the largest amount of surface area, do not call for extra machining and are cost-effective. They also represent the most common thermowell design. Stepped shank thermowells, in comparison to straight shank thermowells, provide smoother speeds around the barrel because they have less surface area. Tapered shank thermowells provide increased sensitivity and have the lowest surface area of all three designs.
Important factors to keep in mind when selecting a thermowell are stem length, bore diameter, lagging extensions, and the thickness of the matter in which the thermowell is rested. The stem length is the distance between the bore and the end of the wall. Bore diameter is the size of the opening that the probe will be put in. Lagging extensions take into consideration the pipe fittings, insulation, and walls that the sensor will go through. Finally, the length from the connection to the bore represents the lag length.