What Are Thermocouples and Their Uses In Industries?

Thermocouple probes and sensors are used in various machines and appliances ranging from automobiles to water heaters and ovens. They also play a significant role in industries such as food and dairy, nuclear reactors, pharmaceuticals, and steel-making.

If you are unaware of what is a thermocouple and want to know more about their working and uses in industries, today we bring you an article on the same.

What Is A Thermocouple?

A thermocouple refers to an electronic device that makes use of the thermoelectric effect and identifies the differing temperature between two electrical conductors. The two electrical conductors used in a thermocouple will always be dissimilar and will be connected in such a way to form an electrical junction in the circuit.

How Does Thermocouple Works?

A discovery by Thomas J. Seebeck, who was a physicist from Germany, led to the development of the thermocouple device.

Seebeck found that when two dissimilar metals are joined to one other by the ends, a difference in temperature occurs in the joint along with a magnetic field. Seebeck, at the time, referred to this as thermo-magnetism.

What Are The Different Types of Thermocouples?

There are different types of thermocouples out there, and the classification is by various parameters like the ruggedness, operational conditions, and maximum temperature that can be measured using the thermocouple.

Type K Thermocouple:

Type K thermocouple is the most widely used out of all. They are made using Nikel/Alumel and Nickel/Chromium. The Type K thermocouple can measure temperatures ranging from -270°C to 1260°C.

Type J Thermocouple:

Another common type is Type J thermocouple. Type J is less popular than Type K because of its shorter lifespan and lower range of temperature measurement. Type J thermocouples are made using Iron and Constantan and can measure temperatures between -210°C to 760°C.

Type E Thermocouple

Type E thermocouple is well-known for their accuracy which is better than the Type K or Type J thermocouple, especially at higher temperatures. Type E thermocouple is made using Constantan and Nickel/Chromium and can measure temperatures between -270°C to 870°C.

Type T Thermocouple

Type T thermocouples are primarily used in cryogenic appliances and freezers with shallow temperatures as they are very stable in shallow temperatures. Type T thermocouples originate from Constantan and Copper, and the temperature range that can be measured is between -270°C to 370°C.

Type N Thermocouple

Type N thermocouples are made using Nisil and Nicrosil and share the accuracy as that of Type K thermocouples. However, Type N thermocouples are cheaper and can measure temperatures between -270°C to 392°C.

Type S Thermocouple

Type S thermocouples is used mainly in the pharmaceutical and biotech industries. Type S thermocouples are highly stable and made of Platinum and Platinum Rhodium – 10%. Temperatures between -50°C to 1480°C can be measured using Type S thermocouple.

Type R Thermocouple

Type R thermocouples is made of Platinum Rhodium-13% and Platinum. Even though similar to Type S thermocouples, Type R thermocouples are quite expensive because of the higher content of Platinum Rhodium.

Type R thermocouples are very stable and accurate in measurements and can detect temperatures within the range of -50°C and 1480°C.

Type B Thermocouple

Type B thermocouples are made of Platinum Rhodium-30% and Platinum Rhodium-6%. The higher content of Platinum Rhodium makes Type B thermocouples the most expensive, highly stable, and highly accurate thermocouples of all.

Type B thermocouples can measure temperatures between 0°C and 1700°C.

What Are The Uses of Thermocouples In Industries?

Thermocouples are used widely in daily appliances such as ovens, electric heaters, and more to make sure that only sufficient amount of heat is provided. Thermocouples are also used in gas stoves to make sure that gas leak does not happen as the gas input to the furnace is cut off when the burner is not lit.

Not just in everyday appliances, but thermocouples play a crucial role when it comes to industries as well.

Below are some of the common uses of thermocouples in industries:

  • In reactive furnaces including nuclear reactors to monitor and maintain a safe temperature inside the furnace.
  • Temperature measurements in diesel engines, gas turbines, and kilns.
  • In iron and steel industries thermocouples is used to monitor the chemistry and temperature throughout the making.
  • Thermocouples also used in diagnostic testing in automobiles.
  • In pharmaceutical and biotech industries.
  • In dairy and food industries for pasteurization and to maintain temperature during the preparation of food thermocouples plays a crucial role.

Final Words

We hope that the above article was detailed enough to provide you with ample information on thermocouples, types of thermocouples, and their uses in industries.

In case you have any questions related to thermocouples, leave a comment below and we will help you out.