What is a thermowell?

Almost all accurate temperature measurements are made when the temperature sensor is in direct contact with the process flow. This process current can be corrosive or erosive and cause rapid damage to the uncoated sensor, a common way to prevent this is to use a thermowell.
Technical specifications of thermowell

A thermowell is a cylindrical connection mounted to protect a temperature sensor with one end closed and the other open. The closed end is placed in the process and the temperature sensor, which is a thermocouple or resistance sensor or thermometer, is inside the open end. Temperature sensors are usually mounted on the thermowell by a spring to ensure that the sensor is connected to the thermowell. The open end of the thermowell is usually located in the open air outside the process piping, and in the event of a sensor failure, it can be easily replaced without emptying the tank or tube.
Types of thermowells

Smooth thermowell

In smooth thermowell, the diameter of the immersion part is the same in all parts and has good protection against corrosion and abrasion.

Cone thermocouple

In a funnel-shaped thermowell, the diameter of the thermowell decreases as it approaches the tip of the immersion length. These thermowells are used in cases where the flow rate of the fluid is very high, conical thermowells are used for liquid fluid with a speed of more than 5 meters per second and gaseous fluids with a speed of more than 15 meters per second.

Stairwell

Stair thermowell has the least material in the immersion tip and has a fast time response.