Tiankang thermocouple

Tiankang thermocouple

Temperature is one of the important parameters that need to be measured and controlled in industrial production processes. Thermocouples are widely used in temperature measurement, with many advantages such as simple structure, convenient manufacturing, wide measurement range, high accuracy, low inertia, and easy remote transmission of output signals. In addition, as thermocouples are active sensors that do not require an external power source for measurement, they are very convenient to use and are often used to measure the temperature of gases or liquids in furnaces and pipelines, as well as the surface temperature of solids.

Working principle: When two different conductors or semiconductors A and B form a circuit, and their two ends are connected to each other, as long as the temperature at the two nodes is different, with one end having a temperature of T, it is called the working end or hot end, and the other end having a temperature of T0, it is called the free end (also known as the reference end) or cold end. In the circuit, an electromotive force will be generated, and the direction and magnitude of this electromotive force are related to the material of the conductor and the temperature of the two nodes. This phenomenon is called the "thermoelectric effect", and the circuit composed of two conductors is called a "thermocouple". These two conductors are called "thermoelectric poles", and the generated electromotive force is called the "thermoelectric potential".

Thermoelectric potential consists of two parts of electromotive force, one is the contact electromotive force between two conductors, and the other is the temperature difference electromotive force of a single conductor.

The magnitude of thermoelectric potential in a thermocouple circuit is only related to the temperature of the conductor material and the two contact points that make up the thermocouple, and is independent of the shape and size of the thermocouple. When the two electrode materials of the thermocouple are fixed, the thermoelectric potential is a function of the temperature difference between the two contact points t and t0. namely

The formula has been widely used in practical temperature measurement. Because the cold end t0 is constant, the thermoelectric potential generated by the thermocouple only changes with the temperature of the hot end (measuring end), that is, a certain thermoelectric potential corresponds to a certain temperature. We can achieve temperature measurement by measuring thermoelectric potential.

Tiankang thermocouple

Technical advantages of thermocouples: wide temperature measurement range and relatively stable performance; High measurement accuracy, thermocouple in direct contact with the measured object, unaffected by intermediate media; Fast thermal response time and flexible response of thermocouples to temperature changes; Large measurement range, thermocouple can continuously measure temperature from -40~+1600 ℃; Thermocouples have reliable performance and good mechanical strength. Long service life and convenient installation.

A thermocouple must be composed of two conductor (or semiconductor) materials with different properties but meeting certain requirements to form a circuit. There must be a temperature difference between the measuring end and the reference end of the thermocouple.

Weld two different conductors or semiconductors A and B together to form a closed circuit. When there is a temperature difference between the two attachment points 1 and 2 of conductors A and B, an electromotive force is generated between them, thus forming a current of a certain magnitude in the circuit. This phenomenon is called thermoelectric effect. Thermocouples work by applying this effect.

Thermocouples are actually energy converters that convert thermal energy into electrical energy and measure temperature using the generated thermoelectric potential. Regarding the thermoelectric potential of thermocouples, the following issues should be noted:

1. The thermoelectric potential of a thermocouple is the difference in temperature function between the two ends of the working end of the thermocouple, rather than the temperature difference between the cold end and the working end of the thermocouple;

2. The magnitude of the thermoelectric potential generated by a thermocouple is not related to the length and diameter of the thermocouple when the material is uniform, but only to the composition of the thermocouple material and the temperature difference at both ends;

3. After the composition of the two thermocouple wires is determined, the magnitude of the thermoelectric potential of the thermocouple is only related to the temperature difference of the thermocouple; If the temperature of the cold end of the thermocouple remains constant, the thermoelectric potential entering the thermocouple is only a single value function of the working end temperature. Weld two different materials of conductors or semiconductors A and B together to form a closed circuit, as shown in the figure. When there is a temperature difference between the two attachment points 1 and 2 of conductors A and B, an electromotive force is generated between them, thus forming a current of a certain magnitude in the circuit. Thermocouples work by utilizing this effect.