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All About Thermowells


All About Thermowells

Today on the BBP blog, we’re drilling down and learning all about thermowells. With over 30 years of experience engineering sensors solutions, BBP Sensors is ready to create a custom solution to suit your needs. Our team provides engineered solutions with fast and dependable delivery. Get a quote today!


Thermowells are cylindrical fittings used to protect temperature sensors installed in industrial processes. In addition, a thermowell consists of a tube closed at one end and mounted in the process stream. A temperature sensor such as a thermometer, thermocouple or resistance temperature detector has an open end tube, which is in the open air outside the process piping or vessel and any thermal insulation.

Thermodynamically, the process fluid transfers heat to the thermowell wall, which transfers heat to the sensor. As a result, the sensor’s response to process temperature changes slows down because of the addition of the well. Also, the sensor is replaceable if it fails. Since the mass of the thermowell needs heat to the process temperature, and since the walls of the thermowell conduct heat out of the process, sensor accuracy and responsiveness is negatively impacted by the addition of a thermowell.

Above all, the four most common types of thermowells are threaded, flanged, welded and sanitary. Check out the video below from REOTEMP to learn more about the different kinds of thermowell connection types.

To begin your customized order, click here to view our thermowell calculation form.

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[Via Thomas W. Kerlin, Mitchell P. Johnson (2012)]