Types and uses of wear-resistant thermocouple protection tubes

Wear-resistant thermocouples use special heat-resistant materials and wear-resistant alloy materials as temperature measuring outer sleeves and wear-resistant heads. Depending on the temperature being measured, the selected wear-resistant protective tube material is also different. It uses flange connection or threaded connection. It can be used for long-term temperature measurement in the range of 0-1300 degrees. It is the most ideal temperature sensor for measuring high temperature and wear-resistant environments in metallurgy, chemical industry, cement plant, power plant, and waste incineration industry. The wear-resistant protective tube is equipped with an armored core, which has high wear resistance, corrosion resistance, oxidation resistance, and erosion resistance. The protective tube can also play a good protective role for the internal armored core under high temperature conditions, and the service life can be up to two years. The components of the wear-resistant thermocouple include wear-resistant head, connecting rod, threaded connection or flange, junction box, and armored inner core. The wear-resistant head should be selected according to the actual temperature of the production site, and the connecting rod, threaded connection or flange should be selected according to whether there is a corrosive medium on site.

Types of wear-resistant thermocouple protection tubes:

1. High-temperature alloy wear-resistant: special heat-resistant and wear-resistant alloy materials are used as the temperature measurement outer protection tube, with an armored core inside, which has high corrosion resistance to particle erosion and can provide good protection for the inner core under high temperature conditions. With flange or threaded connection, temperature measurement can be performed between 0-1200℃ for a long time.

2. Composite casting wear-resistant alloy: composite armoring technology is used to add wear-resistant particles to the high-temperature alloy matrix, and precision casting is performed. No turning is required, the casing has high hardness, high-temperature oxidation resistance, and there are a few casting defects but it does not affect high-temperature wear resistance and sealing. It is the most common high-temperature wear-resistant casing, and the operating temperature is 800-1200℃.

3. Metal ceramic wear-resistant: recrystallized silicon carbide metal ceramic protection tube is used, the high temperature can reach 1300℃, and the K-graded or S-graded armored core is installed inside, which is specially suitable for temperature measurement in high-temperature and strong wear-resistant working conditions such as cement kiln tail and circulating fluidized bed.

4. Ion implantation of tungsten carbide: Using stainless steel as the matrix, tungsten carbide particles are implanted on the surface of the casing using ion implantation technology. It has high hardness, high strength, and special wear resistance. The thickness of the wear-resistant layer is 0.5-1.5mm, hard outside and tough inside, the smallest diameter can reach φ8, the surface quality is good, and the operating temperature is 0-800℃. The service life in the coal mill of the power plant is more than 2 years.

5. Iron-aluminum porcelain protection tube: The iron base contains aluminum and A12O3 powder is cleverly added to make iron-aluminum porcelain (TLC) with special gold content. The iron-aluminum porcelain alloy is made into a thermocouple (resistance) protection tube, which becomes the key part of the iron-aluminum porcelain thermocouple (resistance)-iron-aluminum porcelain protection tube. According to the working temperature, wear conditions, medium type, pressure and other conditions, different series of iron-aluminum porcelain protection tubes are made. The existing series are: TLC, TLC1, TLC2, TLC3, TLC4 five series.

TLC type: resistant to hydrochloric acid, nitric acid, sulfuric acid, sodium hydroxide, potassium hydroxide solution. The working temperature is divided into 350 degrees and 750 degrees.

TLC1 type: resistant to oxidation, sulfidation, zinc vapor corrosion, high wear resistance, good heat and shock resistance, working temperature 1100 degrees.

TLC2 type: working temperature 1250°C, wear resistance is lower than TLC1 type, compared with ceramic tube, thermal shock resistance, high temperature heat strength, working pressure (16MPa, especially suitable for 1250°C thermocouple protection tube with graduation number S.

TLC3 type: improved from TLC2 type, in addition to the characteristics of TLC2 type, has a special improvement in wear resistance, which is much higher than TLC1 type. Under the same working conditions, it can double the service life. Working temperature 1300°C.

TLC4 type: improved from TLC1 type, in addition to the characteristics of TLC1 type, has a special improvement in wear resistance, which is much higher than TLC1 type. Under the same working conditions, it can triple the service life. Working temperature 1100°C. After actual use, the life of the protection tube for temperature measurement at the inlet and outlet of the ball mill can reach 36 months.