The basic principle of thermocouple spot welding head

The basic principle of thermocouple spot welding head is to form a closed circuit with two different materials of conductors. When there is a temperature gradient at both ends, there will be current passing through the circuit, and there is an electromotive force between the two ends - thermoelectric electromotive force, which is called the Seebeck effect. Two homogeneous conductors with different compositions are thermoelectric electrodes, with the working end at the higher temperature and the free end at the lower temperature. The free end is usually at a constant temperature.
When a third metal material is connected to the thermocouple circuit, as long as the temperature of the two contacts of the material is the same, the thermoelectric potential generated by the thermocouple will remain unchanged, that is, not affected by the connection of the third metal to the circuit. Therefore, when measuring temperature with a thermocouple solder joint, a measuring instrument can be connected, and after measuring the thermoelectric force, the temperature of the measured medium can be determined. When measuring temperature with a thermocouple, it is required that the temperature of its cold end (the measuring end is the hot end, and the end connected to the measuring circuit through a lead is called the cold end) remains constant, so that the magnitude of its thermoelectric potential is proportional to the measured temperature. If the temperature of the cold end changes during measurement, it will seriously affect the accuracy of the measurement. Taking certain measures at the cold end to compensate for the impact caused by temperature changes at the cold end is called normal cold end compensation for thermocouples. Use dedicated compensating wires to connect with measuring instruments.
Thermocouple spot welding head is a temperature sensing element, which is a primary instrument. Thermocouples directly measure temperature. A closed circuit composed of two conductors with different composition materials. Due to the different materials, different electron densities generate electron diffusion, and after stable equilibrium, an electric potential is generated. When there is a gradient temperature at both ends, a current is generated in the circuit, generating thermoelectric electromotive force. The larger the temperature difference, the greater the current will be. After measuring the thermoelectric electromotive force, the temperature value can be determined. A thermocouple is actually an energy converter that can convert thermal energy into electrical energy.
The technical advantages of thermocouple spot welding head: the thermocouple has a 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; The measurement range is large, and thermocouples can continuously measure temperature from -40 to+1600 ℃; Thermocouples have reliable performance and good mechanical strength. Long service life and convenient installation.
Solder two different types of conductors or semiconductors A and B together to form a closed loop. 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 the two, forming a current of a certain magnitude in the circuit. This phenomenon is called the thermoelectric effect. Thermocouples work by applying this effect.