The working principle of thermocouple spot welding head

issuing time:2021-03-22

Welding head is that two conductors of different components form a closed loop. When there is a temperature gradient at both ends, there will be current passing through the loop. At this time, there is an electromotive force between the two ends— —Thermal electromotive force, which is the so-called SeeAt present, the basic principle of our common thermocouple spot beck effect.Two homogeneous conductors with different compositions are thermoelectrodes, the end with a higher temperature is the working end, and the end with the temperature length is the free end, and the free end is usually at a certain constant temperature.

When the third metal material is connected in the thermocouple circuit, as long as the temperature of the two junctions of the material is the same, the thermoelectric potential generated by the thermocouple will remain unchanged, that is, it will not be affected by the third metal in the circuit.Therefore, when using the thermocouple spot welding head to measure the temperature, the measuring instrument can be connected and the temperature of the measured medium can be known after the thermoelectromotive force is measured.When a thermocouple measures temperature, the temperature of its cold end (the measuring end is the hot end, and the end connected to the measurement circuit through the lead is called the cold end) is required to maintain the same temperature, so that its thermoelectric potential has a certain proportional relationship with the measured temperature.If the (environment) temperature of the cold junction changes during measurement, it will seriously affect the accuracy of the measurement.Taking certain measures at the cold junction to compensate for the influence caused by the temperature change of the cold junction is called the cold junction compensation of the thermocouple. Dedicated compensation wire for connection with measuring instrument.

The thermocouple spot welding head is a kind of temperature sensing element and a primary instrument. The thermocouple directly measures the temperature.A closed circuit composed of two conductors with different composition materials. Due to the different materials, different electron densities produce electron diffusion, and after stable equilibrium, an electric potential is generated.When there is a gradient temperature at both ends, a current will be generated in the loop, and a thermoelectromotive force will be generated. The greater the temperature difference, the greater the current.The temperature value can be known after measuring the thermoelectromotive force. A thermocouple is actually an energy converter that converts heat energy into electrical energy.

The technical advantages of the thermocouple spot welding head: the thermocouple has a wide temperature measurement range and relatively stable performance; the measurement accuracy is high, the thermocouple is in direct contact with the measured object, and is not affected by the intermediate medium. The thermal response time is fast, and the thermocouple responds flexibly to changing temperature; the measuring range is large, the thermocouple can continuously measure the temperature of -40~+1600℃; the thermocouple has reliable performance and good mechanical strength. Long service life and easy installation.

The conductors or semiconductors A and B of two different materials are welded together to form a closed loop.When there is a temperature difference between the two attachment points 1 and 2 of the conductors A and B, an electromotive force is generated between the two, so a large current is formed in the loop. This phenomenon is called the thermoelectric effect.Thermocouples work using this effect.

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