October 15, 2020 Choose the Right Thermocouple for the Right Application

To make sure you get the right thermocouple for your purpose it’s beneficial to know which application they are designed for.

Thermocouples are popular in several industries including the medical, food and motor industries. These temperature sensors, when configured correctly, provide accurate temperature readings over a broad temperature range. They’re cost-effective and are known for their durability as well as being versatile.

To ensure you get the right thermocouple for your purpose, it’s good to know the different types available and which application they’re designed for. When searching for thermocouples you’ll find the most common ones are classified as Type J, K, T and E. Thermocouples are grouped according to the maximum temperature measurements they can take, in which environment they can operate and their durability.

Types of Thermocouples

When deciding on the right thermocouple, ask yourself the following questions:

• What application will I need the thermocouple for?
• What are the maximum and minimum temperature ranges I can expect the thermocouple to be exposed to?
• What level of ruggedness do I need from the thermocouple? What kind of abrasion, chemical and vibration resistance will it need?
• Does the thermocouple have any installation requirements?

It’s a good idea to use companies who specialize in such products. They can advise you which is the right one for your application such as the thermocouples made by Pyrosales.

1. Beaded Wire Thermocouples

The beaded wire thermocouple is the most basic type of thermocouple. It’s made of two insulated thermocouple wires combined with a welded bead. This bead is exposed so the thermocouple should never be used with corrosive liquids. They’re also not suited for metal surfaces used to earth electrical systems. This type of thermocouple is designed to be small and have quick response times.

If you’re looking for thermocouples to read surface and air temperatures the beaded wire thermocouple is a good option. It’s also used often for gas temperature measurements.

2. Thermocouple Surface Probes

Taking temperature measurements of a solid surface area can be challenging. It requires the thermocouple to have direct overall contact with the surface being measured. The junction of the surface probe is flat and pliable allowing for constant contact with the surface being measured. Some surface probes have rotational capabilities making them perfect for a moving surface.

This type of thermocouple is ideal for general and high temperature surfaces. One example of where you can use a surface probe is to measure solar panel temperatures.

3. Thermocouple Probes

The thermocouple probe consists of the wire being integrated inside a sheath. The sheath is most commonly a ceramic or metal tube. Stainless steel sheaths are preferred for their compatibility with a wide range of chemicals. Ceramic sheaths are ideal for high temperatures. The tips of the probes can be insulated, grounded or exposed.

The exposed thermocouple probes are best suited for dry air and non-corrosive gas temperature measurements. They have the fastest response times. The grounded ones, while also having fast response times, are not suited for electrical earth loops. Insulated thermocouples work well for liquid-based substances.

Final Thoughts

Thermocouples are used in a wide range of applications. By understanding the design of a specific thermocouple, you’ll be better placed to choose the right one for your purpose. Manufacturers such as Pyrosales are able to custom design temperature instruments to suit specific requirements. Thermocouples play a vital role in measuring temperatures, so getting the right one for the right application is essential.

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