Introduction to the use of armored thermocouples and hot air stove thermocouples?

The thermoelectric potential of armored thermocouples will increase as the temperature at the measuring end rises. The magnitude of the thermoelectric potential is only related to the material of the thermocouple conductor and the temperature difference at both ends, and is independent of the length and diameter of the thermoelectric electrode. Two conductors with different compositions are welded at both ends to form a circuit. The temperature measuring end is called the working end, and the wiring terminal end is called the cold end, also known as the reference end. When there is a temperature difference between the working end and the reference end, a thermal current will be generated in the circuit. When connected to a display instrument, the instrument will indicate the corresponding temperature value of the thermoelectric potential generated by the thermocouple. Thermocouples for hot blast furnaces in steel plants are mainly used in the steel industry to provide hot air for the smelting process. The dome temperature measuring thermocouple operates at high temperatures of 1200-1250 ℃ for a long time, with a usage temperature of up to 1280 ℃, and has strong vibration during the air supply process. Due to the different coal qualities used by various enterprises, the cleanliness of the produced coal gas also varies. During the combustion process of hot blast stoves, sulfur, phosphorus and other compounds are often present, requiring thermocouple protective sleeves to be able to withstand high-temperature airflow erosion, particle wear and high-temperature gas corrosion. Traditional thermocouple protective sleeves such as steel jade, disilicified keys, and ordinary silicon carbide are prone to brittle fracture, wire contamination, and corrosion due to porosity, high temperature strength, and high temperature brittleness. Thermocouples have a short service life and no reliable operating cycle. The high-temperature corrosion failure time of nickel based high-temperature alloy protective casing in the presence of phosphides in coal gas is about 20-30 hours. Our company has continuously summarized experience and applied achievements in the field of materials in the long-term practice of temperature measurement of various hot blast stove domes. We use special SiC or heat-resistant alloys as the outer protective tube, corundum as the inner protective tube, and treat the measuring end. We have successfully developed this specialized thermocouple, which has been used on hot blast stove domes by relevant users for more than six months.

The structural principle of armored thermocouples is composed of a conductor, high insulation magnesium oxide, and a protective tube made of 1Cr18Ni9Ti stainless steel, which is pulled together multiple times. Armored thermocouple products are mainly composed of junction boxes, terminal blocks, and armored thermocouples, and are equipped with various installation and fixing devices. Armored thermocouples are divided into two types: insulated and shell connected. It has many advantages such as bending ability, high pressure resistance, fast thermal response time, and durability. Like industrial sensors, it is usually used in conjunction with display instruments, recording instruments, and electronic regulators to measure temperature. At the same time, it can also be used as a temperature sensing element. It can directly measure the temperature of liquids, vapors, gas media, and solid surfaces in the range of 0 ℃~800 ℃ during various production processes. Compared to others, armored thermocouples have advantages such as bendability, high voltage resistance, short thermal response time, and durability. The temperature measurement principle of thermocouples is based on the thermoelectric effect. Connecting two different conductors or semiconductors into a closed circuit, when the temperatures at the two junctions are different, a thermoelectric potential will be generated in the circuit. This phenomenon is called thermoelectric effect, also known as Seebeck effect. Armored thermocouples, as temperature measurement sensors, are usually used in conjunction with temperature transmitters, regulators, and display instruments to form process control systems. They are used to directly measure or control the temperature of fluids, vapors, gas media, and solid surfaces within the range of 0-1800 ℃ in various production processes. Armored thermocouples have many advantages such as bending, high voltage resistance, fast thermal response time, and durability. Like industrial assembled thermocouples, they are commonly used as temperature sensors in conjunction with display instruments, recording instruments, and electronic regulators. The verification method and device for metal melt rapid armored thermocouples. The device mainly consists of a flat heating coil that can accommodate two quartz tubes at the ends of the tested couples, two armored thermocouples with the same shape as the tested couples, and corresponding temperature control display output devices.