ThermocoupleThermocouple

Presented by:

J K SHREEJ K SHREE5115/TRG/2015/G5115/TRG/2015/G

INTRODUCTION

A thermocouple is a temperature-measuring device consisting oftwo dissimilar conductors that contact each other at one junction.

It produces a voltage when the temperature of one of the endsdiffers from the reference temperature at other end of the circuit. 

Metal A

Metal B

Junction

Voltmeter

THERMOCOUPLES: SEEBECK EFFECT The Seebeck effect is the conversion of thermal

energy/temperature differences directly into electrical energy or electricity.

The change in the voltage is proportional to the temperature difference between the junctions when the ends are connected to form a loop.

PRINCIPLE OF OPERATIONThe EMF generated by

the Seebeck effect is due to the temperature gradient along the wire.

The EMF is not generated

at the junction between two dissimilar wires.

APPLICATIONS

1.Steel industry2.Gas appliance safety3.Thermopile radiation sensors4.Manufacturing 5.Power production6.Thermoelectric cooling7.Process plants8.Thermocouple as vacuum gauge9. Heaters

A thermocouple (the right most tube) inside the burner assembly of a water heater.

Thermocouple connection in gas appliances. The end ball (contact) on the left is insulated from the fitting by an insulating washer. The thermocouple line consists of copper wire, insulator and outer metal (usually copper) sheath which is also used as ground.

TYPES & SPECIFICATIONS

Advantages

DISCOVERED FACTS

• Construction of Thermocouple• How thermocouple types are classified

based on material used?• Seebeck effect• Range of temperature that it operates

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