What is thermocouple. how it is constructed and what are the applications of thermocoupling?
Answers
The thermocouple is a temperature measuring device. It uses for measuring the temperature at one particular point. In other words, it is a type of sensor used for measuring the temperature in the form of an electric current or the EMF.The thermocouple consists two dissimilar metals. These metals are welded together at the junction point. This junction considers as the measuring point. The junction point categorises into three types.
Ungrounded Junction – In ungrounded junction, the conductors are entirely isolated from the protective sheath. It is used for high-pressure application works. The major advantage of using such type of junction is that it reduces the effect of the stray magnetic field.
Grounded Junction – In such type of junction the metals and protective sheath are welded together. The grounded junction use for measuring the temperature in the corrosive environment. This junction provides resistance to the noise.
Exposed Junction – Such type of junction uses in the places where fast response requires. The exposed junction is used for measuring the temperature of the gas.
Thermocouples are the most popular type of temperature sensors. They are used as hospital thermometers, and in diagnostics testing for vehicle engines. Some gas appliances such as boilers, water heaters, and ovens use them as safety features; if the pilot light is out, the thermocouple stops the gas valve from operating. They are also used as an aid in milk pasteurization, and as food thermometers. In industry, they are valuable as probes and sensors.