Design of temperature testing sensors in well type annealing furnaces

The temperature sensors used in the well type annealing furnace can be divided into contact type and non-contact type according to the heat transfer form. At the junction of any two objects with different temperatures, heat exchange inevitably occurs until the two temperatures are equal. The temperature sensor manufactured based on this principle is called a contact thermometer. The non-contact temperature sensor is based on the principle of measuring the radiation energy generated by objects. Contact sensors have the characteristics of sensitive response and high accuracy. Contact sensors are divided into expansion sensors, thermal resistance temperature sensors, and thermocouple temperature sensors. Thermocouples are commonly used temperature sensors in industry. It has the advantages of good durability, long service life, low cost, and high accuracy. The bus type multi-channel thermometer introduced in this article uses thermocouple sensors.
The thermocouple used in the well type annealing furnace is a temperature sensing element made using the principle of thermoelectric effect. The temperature measurement principle of the thermocouple is relatively simple, that is, if the temperature T and T are at two connection points, there are two different conductors A and B forming a closed circuit. Then, a thermoelectric electromotive force is generated in the circuit to form a current, which is known as the thermoelectric effect. The two conductors A and B become thermoelectric electrodes, and their combination becomes a thermocouple. The t end in contact with the thermal field becomes the working end, and the other end is called the free end. The thermoelectric potential value of a thermocouple is related to the properties of the metal material that makes up the thermocouple, the temperature difference between the measuring end and the cold end, and is independent of the size of the metal wire, the temperature along the wire, and the position of the thermoelectric potential measurement point in the circuit. The T-end is called the measurement end, and the T-end is called the reference end (cold end). Thermocouples are widely used for temperature detection.
Currently, thermocouple temperature detection has been widely applied in industry. Compared with other temperature sensors, thermocouples have many advantages, such as high detection accuracy. Remote detection can be achieved, facilitating centralized control, digital display, and automatic recording. Based on this characteristic, the bus type multi-channel thermometer can detect the temperature in a space far away from the well type annealing furnace. It can be made into small-sized thermocouples with small thermal inertia and fast reaction speed. Can be used for dynamic temperature detection and surface temperature detection.