Essentially, a thermocouple is a temperature sensor or thermometer. It’s a device used to measure and monitor temperature within an industrial setting and, thanks to its unique properties, it has a diverse range of applications. Here, our team of experts share their knowledge on the topic and answer your most frequently asked questions about J type and K type thermocouple sensors.
What is the difference between a J type and K type thermocouple?
J type and K type thermocouples work in exactly the same way. They consist of two wires, which are welded together at one end to create a junction. When this junction experiences a change in temperature, a voltage is produced – and this voltage can be used to determine the temperature.
Yet, despite this similarity, they differ on a few key factors:
Construction
Whilst J type thermocouples are made from iron and constantan, type K thermocouples are made from a nickel/chromium alloy (chromel) and nickel/aluminium alloy (alumel).
Temperature range
A J type thermocouple is capable of measuring temperatures from 0°C – 816°C. By contrast, a K type thermocouple can withstand temperatures between 0°C and 1260°C.
Cost
Due to the reasons outlined above, K type thermocouple sensors are usually much more expensive to buy than J type thermocouples.
Is a thermocouple suitable for my industry?
J type thermocouples and K type thermocouples are suitable for use in many different industries. For example, those available here – at Cartridge Heaters – are frequently employed within:
- the aerospace industry
- the heat and energy industry
- the food production industry
- the metal industry
- the medical sector
- pharmaceuticals
If you need a way to measure high temperatures in an industrial setting, a thermocouple is an accurate and reliable option for most – and there’s bound to be a product to suit your needs.
What are the benefits and uses of a K type thermocouple?
Type K thermocouples are regarded as a ‘general purpose’ thermocouple. They’re a versatile choice that can be used for a diverse range of applications. Thanks to their wide temperature range, they’re capable of withstanding high temperatures (unlike a gauge) and are commonly used in process plants (e.g. chemical and petroleum production) and to check the safety of heating appliances.
Due to the materials from which they are made (i.e. chromel and alumel), K type thermocouples also demonstrate excellent resistance to oxidation and acidity. This means they’re a great choice for clean environments, with an oxidative or corrosive atmosphere. They can also be successfully immersed in an oxidative or corrosive fluid, without being damaged in the process.
What are the benefits and uses of a J type thermocouple?
Although they may have a smaller temperature range than type K, J type thermocouples are still just as effective and reliable – and they’re available for a much cheaper price. As a result, they’re a popular option for heat processes (such as the manufacture of plastic and resin) and are commonly used to monitor temperatures in inert materials and vacuum applications.
J type thermocouples also demonstrate resistance to corrosion, making them ideal for use in electrical furnaces. However, unlike type K thermocouples, they’re susceptible to oxidisation – and, as such, should not be used in oxidative environments or damp conditions.
Which is the right thermocouple for me?
The right thermocouple for you will depend on its intended application and the temperatures that you wish to monitor. If you’re unsure which is the best product for your needs, please feel free to get in touch. Our team of experts have outstanding knowledge of both J type and K type thermocouples. They’re happy to answer your questions and will recommend the best thermocouple for you.
We currently have a range of high-quality self-powered thermocouples to choose from, with something to suit all requirements and budgets. So why not browse the collection today and, if you need a little help, give us a call on 0121 439 8932. Alternatively, send an email to sales@cartridgeheaters.co.uk and we’ll respond to your enquiry as soon as possible.