Why Thermometers Need Thermowells for Protection

Are the temperature sensors inside your equipment protected? If you have temperature sensors like thermocouples, thermistors or bimetal thermometers, you should protect them with a thermowell.

What's a thermowell? A thermowell serves as a casing that surrounds the temperature sensor and offers protection from damage, excess pressure, corrosion, and material velocity.

Here's what a thermowell looks like. You'll note that a thermowell is usually mounted permanently to the vessel or pipe like this:

The advantages of a thermowell

Thermowells offer a variety of benefits, which include:

  • Increased longevity of temperatures sensors

By using a thermowell, you're applying a barrier that safeguards the temperature sensor and protects it from the elements inside. That means your temperatures sensor will last longer.

  • Saving money

Since the thermowell is shielding the temperature sensor from damage and harsh environments, you'll replace sensors less frequently – and that means more money in your pocket.

  • Improved service options

You can replace or service the temperature sensor without draining the system, provided a thermowell is in place. That means you don't have to shut down to handle maintenance.

What to know when picking a thermowell

Given the benefits that thermowells provide, it's not surprising to see more companies use them. When you're ready to put a thermowell in place, here are some tips to make sure you get the right one for the job:

  • Thermowells vary in design

There are three different kinds of thermowells, each has its own stem shape. The various designs are:

Straight thermowell. As you may have guessed, this thermowell is a long, straight tube with a consistent diameter. It's known to fight corrosion.

Stepped thermowell. This option steps down in size from ¾" to ½" in diameter. It's best for equipment that deals with smoother velocities or those that change temperature rapidly.

Tapered thermowell. The diameter of this thermowell decreases gradually from base to tip. It's used in high-velocity applications and can handle vibrations within the system.  

  • Thermowells have a variety of connection types

A thermowell can be connected to a system via different connection types. The most common types are:

Threaded. Best for smaller diameter wells with low corrosion that aren't changed frequently.

Flanged. Best for larger pipes with higher corrosion rates and more frequent replacement.

Welded. Best for non-corrosive environments with no replacement needed.

  • Thermowells are made out of many different materials

You can buy a thermowell made out of anything from carbon steels to titanium. Selecting the right material all depends on how and where the thermowell is used.

You can get thermowells made out of:

  • Carbon steel
  • Chromium
  • Socket Weld
  • Stainless Steel
  • Titanium

The most commonly chosen material for a thermowell is stainless steel because it's affordable, can withstand heat and pressure, and prevents corrosion.

Wrap up

Installing a thermowell to protect your temperature sensors is a wise, cost-effective decision. As you select the right thermowell for your application, be sure to check out the options available through DirectMaterial.com. You'll find a great assortment of stainless steel thermowells at great prices on our website.

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