A sheathed thermocouple is used to protect the thermocouple junction, which measures temperature, from attack by corrosive environments.
It comes in two types: grounded and ungrounded. Each construction method has its benefits, but which should you choose?
This article will discuss the differences between them and help you decide which one is best for your application.
Grounded vs Ungrounded Thermocouple: Which One Is Ideal For Your Needs?
Other Factors to Consider When Choosing a Thermocouple?
There are several other factors to consider before selecting a sheathed thermocouple for your application. These include the operating temperature range, accuracy and price.
Operating Temperature Range
This is the operating temperature range over which the thermocouple type can accurately measure temperature. Thermocouples are available in a wide variety of operating temperature ranges with Type T going from -200°C to 370°C, Type K from -200°C to 1200°C and Type S from 0°C to +1600°C. Tungsten/Rhenium thermocouple temperature sensors are available going right up to 2500°C.
A thermocouple's accuracy is the measurement's maximum error. Thermocouples have an inherent accuracy that is affected by many factors, such as material properties, construction, and calibration. Therefore, it is vital to choose a thermocouple with an accuracy that is appropriate for your application.
Copper vs Constantan (T) or Iron vs Constantan (J) are much cheaper materials than the Platinum/Rhenium vs Platinum used in Types R & S. However, the lower priced materials are only useable over a lower temperature range.