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What is a Thermowell and How Does it Work?

Pyrosales design many temperature solutions for numerous industries, most solution will include the use of a temperature sensor and a thermowell. What is a thermowell and how does it work?

A thermowell is a cylindrical fitting used to protect temperature sensors installed when measuring temperature.  The thermowell is used when sensors such as thermocouples, RTD, temperature gauges and thermistors, are used in industrial applications where the sensor may be exposed to conditions that can damage the temperature elements.

The industrial conditions that can damage the temperature elements are vibration, chemical substance, and pressure to name a few. To maintain the integrity, life, and accuracy of the temperature sensor we use a thermowell to protect the sensor.

How the thermowell works is, the thermowell is insert either by welding or threaded flange into the tank/unit, where the process which requires temperature measurement is. A temperature sensor equal in length to the thermowell is then inserted into the thermowells open end, for best results the tip of the temperature sensor must reach the bottom of the thermowell to have accurate readings through the wall of the thermowell. The advantages of a thermowell are the sensor is protected, the removal of a failed sensor does not shut down the process. This makes the installation of a thermowell cost effective.

There are different styles of thermowells usually distinguished by their stem or how they were manufactured.

Thermowells can be machined from solid bar stock or fabricated from pipe. Fabricated thermowells offer a lower cost alternative where high pressure is not a design consideration. Standard thread forms are BSP and NPT (others available to order), and flange size and rating can be supplied to suit any requirements.

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Pyrosales can assist in choosing the design and material your thermowell and temperature sensor should be manufactured from for the conditions of your process.