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When Should I Use a Coated Thermowell?

Thermowells | coated thermowell

Thermowells are used to protect your temperature measurement instruments from the elements, which means they are often exposed to extreme environments and temperatures. Protecting the thermowell can help keep your temperature instruments safe and your application running.

But how do you protect an instrument that’s designed to protect other instruments?

A protective coating on your thermowell can help keep it safe in an application. This article will discuss coated thermowells and how they can be used to protect your process.

What is Thermowell Coating?

A coated thermowell can prevent contamination in critical applications and prolong the life of your thermowell. A coating can protect thermowells from corrosion, erosion and extreme temperatures.

It can also prevent contamination in food/beverage and chemical applications that have strict sanitary requirements by helping to ensure the thermowell does not fail.

What type of coating is best? There are a number of different coatings to choose from depending on your application.

Thermowell Coating Types

Though there are a variety of coatings available on the market, PTFE and stellite are the most commonly used to protect thermowells.

Perfluoroalkoxy (PFA) and Polytetrafluoroethylene (PTFE) coatings have similar properties. PFA and PTFE provide superior corrosion resistance in aggressive media, such as acid and corrosive processes. PFA and PTFE have several unique properties that make them suitable for use in chemical and medical applications.

PFA and PTFE have the following properties:

  • Working temperature from -200°C (-328°F) up to 260°C (500°F)
  • Non-stick characteristics
  • Low-friction surface
  • Resistance to chemicals and solvents
  • Protects against harsh environmental conditions
  • Biocompatibility

Stellite coating in thermowells is applied through thermal spraying. It is a rugged coating made from a group of alloys that contain cobalt-chromium and other materials such as tungsten carbide, aluminum oxide, molybdenum and carbon. These metals are specially designed to resist corrosion, high wear and high temperatures, along with abrasive media such as sand or other particles.

Ordering a Coated Thermowell

If you’re interested in getting a coated thermowell, consider the application in which you’ll be using it to choose what type of coating will work best.

Ashcroft offers thermowell coatings on request. The coatings can be used on all thermowells that we offer (our thermowells are typically made of 316 stainless steel).

The amount of time it takes to receive your coated thermowell depends on the quantity and the type of coating you choose. Please reach out to our experts and request a quote to start your coated thermowell order.

We don’t like to pressure you, but we have more information.

Now that you understand the purpose of a coated thermowell and when it’s appropriate to use one, you will be able to ensure that your temperature measurement equipment remains safe in your application.

Thermowells are the best way to ensure your temperature instruments are protected, and a protective coating on your thermowell will help it last longer.

To learn about calculating thermowell wake frequency, our website offers a helpful webinar explaining the calculation process.

And for more information on thermowells, check out our past articles:

Feel free to reach out to our temperature specialists here at Ashcroft to answer all of your temperature measurement questions!

View Thermowell Wake  Frequency Webinar

About Tino Goncalves, Temperature Product Manager

Tino is the Temperature Product Manager here at Ashcroft. With over 20 years of experience in test and measurement instruments, he holds a Bachelor of Science in management and electrical engineering.