Thermocouples are one of the most important tools that determines the accuracy of temperature measurement. The thermocouple metals used to create the sensing junction have a major impact on the accuracy, temperature sensitivity, and stability of the temperature sensing device. In this blog post, we’ll take a look at the importance of thermocouple metals in determining the accuracy of temperature measurement.
Considerations for Choosing The Right Type of Thermocouple For Your Industry!
Thermocouples are made up of two dissimilar metals which typically meet at a particular junction. This meeting point or the junction between the two metals creates a voltage that is proportional to the temperature difference between the two junctions. The most common thermocouple metals are copper and nickel that are widely used in various industries. Copper has a high thermal conductivity and a low melting point, making it ideal for use in thermocouples. Nickel has a lower thermal conductivity than copper, but a higher melting point. This property of nickel makes it ideal for use in high temperature applications.
- The accuracy of a thermocouple is determined by the material of the two metals used. Different metals have different coefficients of expansion. This means that they will expand at different rates when exposed to heat. The amount of expansion is directly proportional to the temperature change. The most accurate thermocouples are made with pure metals, such as copper and nickel. Thermocouples made with impure metals, such as stainless steel, are less accurate.
- The temperature sensitivity of a thermocouple is determined by the material of the two metals used. The most sensitive thermocouples are made with metals that have a high thermal conductivity, such as copper. Thermocouples made with metals that have a low thermal conductivity, such as nickel, are less sensitive.
- Thermocouples made with different metals can be more stable and less sensitive to temperature changes. For example, thermocouples made with constantan and chromel are often used in high-temperature applications. These metals have a lower thermal conductivity, which means they are less accurate at measuring temperature changes. However, they are much more stable and less sensitive to changes in the surrounding environment.
- The stability of a thermocouple is determined by the material of the two metals used. The most stable thermocouples are made with metals that have a high melting point.
Noble Metal Thermocouples & Their Types!
Industries working at extreme temperatures prefer using noble metal thermocouples because of their stability at higher temperatures and extreme environments, even though these are least sensitive. There are three main types of thermocouples: type B, type R, and type S.
- Type B thermocouples are made of boron and iron. They have a low thermal conductivity, which makes them ideal for use in high-temperature applications. They are also very resistant to oxidation and corrosion.
- Type R thermocouples are made of platinum and rhodium. They have a higher accuracy than type B thermocouples and are often used in precision temperature measurement applications.
- Type S thermocouples are made of silicon and silicon-germanium. They have the highest accuracy of all the thermocouple types and are often used in critical temperature measurement applications.
Most Commonly Used Base Metal Thermocouples!
Thermocouples are also classified according to the base metals used in their construction. These base metal thermocouples are most widely used in industries because of their high sensitivity to temperature changes. The most common types are Type E, Type J, Type K, and Type T.
- Type E thermocouples are made with chromel and constantan. They are the most accurate type of thermocouple and are used in many industrial applications.
- Type J thermocouples are made with iron and constantan. They are less accurate than Type E thermocouples but are still widely used.
- Type K thermocouples are made with chromel and alumel. They are less accurate than Type E thermocouples but have a wider temperature range.
- Type T thermocouples are made with copper and constantan. They are less accurate than Type E thermocouples but have a very wide temperature range.
Heatcon Sensors – The Manufacturer of All Types of High-Quality Thermocouples For Every Industry!
Thermocouples made with different metals can be used for different purposes. It is important to choose the right type of thermocouple for your application. If you are unsure which type will work best for your process, you can contact the experts at Heatcon Sensors who can certainly help you make the best selection based on your process requirements.