Introduction to Thermocouple
OMEGA Engineering Singapore
Engineering, Sensors, Precision Engineering
What is a thermocouple?
A thermocouple is a temperature sensor, which consists of two dissimilar alloys or wires, which are joined together at one end and when the joint is heated or chilled, a voltage is produced that is correlated back to the temperature.
Various types of thermocouples
Thermocouples are available in a variety of different combinations of metals and/or calibrations. The most common types are J, K, T and E. In addition, there are
thermocouples for high temperature uses, such as R, S, C and GB. Each thermocouple type has a different temperature range and the maximum temperature range is limited by the diameter of the thermocouple wire. Very thin thermocouple wires, may not reach the full temperature range.
Selecting the Appropriate Thermocouple
Thermocouples are used in a variety of different industries to measure from a wide range of temperatures, applications, and environmental conditions. To select the appropriate thermocouple, refer to the following criteria:
- Temperature range
- Abrasion and chemical resistance
- Sheath material
- Installation requirements (check compatibility with existing equipment existing holes may determine probe diameter)
Choosing the Appropriate Junction Probe Type
There are three junction types for sheathed thermocouple probes:
- Exposed (Please refer to the three images "Thermocouple Tip Styles" shown in Types of Thermocouples; Thermocouple Probe section)
For grounded junction probes, the thermocouple wires are attached to the inside of the tip of the probe wall, which results in good heat transfer from the probe wall to the thermocouple junction.
, Precision Engineering
, Temperature Sensors