Working principle of dome thermocouple

Common knowledge related to the task principle of dome thermocouple:

Two conductors with different compositions (called thermocouple wires or thermoelectric electrodes) are connected at both ends of a decomposition circuit. When the temperature difference at the junction occurs, an electromotive force will occur in the circuit, which is called thermoelectric effect, and this electromotive force is called thermoelectric potential.

Thermocouples use this principle to stop temperature measurement. The end directly used to measure the temperature of the medium is called the working end (also known as the measuring end), and the other end is called the cold end (also known as the compensating end); The cold end is connected to the performance instrument or supporting instrument, and the performance instrument will indicate the thermoelectric potential generated by the thermocouple.

The construction of arch crown thermocouples is a new type of thermocouple that has been discontinued in order to comply with the detection of blast furnace arch crown temperature.

The selection of inlet Sic recrystallization data for thermocouple maintenance tubes may meet the special requirements of blast furnace temperature measurement. In terms of structure, it has a sealed, vibration resistant, vertical device, and flange structure for rapid loading and unloading.

In order to ensure sufficient thermal exchange between the measuring end of thermocouples and thermal resistors and the measured medium, the position of the measuring point should be reasonably selected, and only precautions should be taken to prevent the installation of thermocouples or thermal resistors near the corners of valves, elbows, pipelines, and equipment.

For thermocouples used to measure the temperature of the core fluid in pipelines, the measuring end should be pulled out to the core of the pipeline (vertical or inclined device). If the diameter of the pipeline for the measured fluid is 200 millimeters, the depth of extraction for the thermocouple or thermistor should be chosen to be 100 millimeters.

For temperature measurement of low-temperature, high-pressure, and high-speed fluids (such as main steam temperature), in order to reduce the resistance of the maintenance sleeve to the fluid and avoid the fracture of the maintenance sleeve under fluid influence, shallow insertion of the maintenance tube method or the use of a hot sleeve thermocouple can be adopted The depth of the shallow insertion thermocouple maintenance sleeve when pulled out of the main steam pipeline should not be less than 75mm; The scale extraction depth of the hot set thermocouple is 100mm.