Difference Between Thermowells & Protection Tubes

Also called "drilled wells," a thermowell is a cylindrical metal solid drilled bar stock installed into a process vessel or pipeline, providing a protective barrier for a temperature sensor. Thermowells are manufactured from drilled bar stock using various materials and alloys and may be coated to protect against corrosive mediums. In many process applications, the thermowell protects the sensor from high pressures, corrosive chemicals, and abrasive materials. It also allows the sensor to be easily removed and replaced for maintenance or calibration.

Protection tubes are similar in design to thermowells but are typically used in lower-pressure and less harsh environments. Protection tubes are commonly made from ceramic or metal protecting temperature sensors from corrosion and physical damage.

Choosing The Proper Thermowell Types for Your Application

Protection tubes and thermowells are available in various materials and style options. For "drilled wells," instrument connection is 1/2"-14 NPT. The length below the threads or the flange is considered the stem, immersion length or "U" length. Proper consideration should be given to temperature, flow, pressure, and environment when choosing the correct thermowell type.

Order from our selection online, or contact us for additional material options. Our staff will gladly assist you in finding the best thermowells and protection tubes for your application requirements.

Types of Thermowells

Many thermowell types have different process connection options, including threaded, flanged, weld-in, socket weld, and Van Stone wells.

• Threaded Thermowells: Threaded thermowells are threaded on one end and can be easily screwed into a process piping system. They are commonly used in applications where the thermowell can be removed for maintenance or calibration.
• Flanged Thermowells: These thermowells have a flange on one end and are bolted onto the process piping system. They are often used in applications where the thermowell needs to be permanently installed.
• Socket Weld Thermowells: Socket weld thermowells are welded directly onto the process piping system for permanent installation.
• Van Stone Thermowells: These thermowells have a flange on both ends and are connected to the process piping system using gaskets and bolts. They are commonly used in applications where the thermowell needs to be easily removed or replaced.

Protection Tube Material Options

At Eustis/Pyrocom, our in-stock protection tube selection includes ceramic and metal material options. To request additional materials, including plastic, quartz, and other materials, contact us,  and our staff will assist you in ordering the required materials.

• Ceramic Protection Tubes: Ceramic protection tubes are used for high-temperature applications (above 2200°F 1205°C), such as with a type R thermocouple.
• Metal Protection Tubes: Metal protection tubes (pipe wells) are manufactured from seamless pipe of various sizes and alloys, including stainless steel (see "Material Selection Guide"). Metal protection tubes can be supplied with or without process threads or a flange.

Contact Us to Learn More About Our Industrial Thermowell & Protection Tubes

Contact Eustis/Pyrocom for more information about our high-performance thermowell and protection tube options. You can also request a quote for pricing information on special orders. At Eustis/Pyrocom, we are dedicated to providing our customers with the best thermowells, thermocouples, infrared sensors, and other industrial temperature product solutions. Choose Eustis/Pyrocom to supply all your thermowell and protection tube requirements.