Correct selection of wear-resistant thermocouples in cement metallurgy industry

In view of the temperature measurement characteristics of the three-stage, four-stage and five-stage cylinder cone temperatures, the middle of the decomposition furnace, the kiln tail smoke and the kiln head hood temperature of the cement dry rotary kiln production line, the ordinary wear-resistant thermocouple cannot meet the special temperature measurement conditions of high temperature resistance and erosion resistance due to the material problem of the protective tube, resulting in a short service life of the thermocouple, increased conditions and expenses, frequent product replacement, lack of guarantee of transmission signals, and long-term alert status of the instrument. At the same time, it adds a lot of workload to the instrument maintenance. This phenomenon is a common problem in the national cement industry.

After many investigations and studies, combined with the characteristics of foreign cement production processes, the advent of special wear-resistant thermocouples for cement plants has not only solved a major problem of wear-resistant temperature control in the cement industry, but also brought considerable economic benefits to each user unit.

The special wear-resistant thermocouples for cement plants are mainly composed of junction boxes, junction tubes, special protection tubes, insulating sleeves, wiring terminals, special lining sleeves, and hot electrodes. The basic structure is equipped with various installation components, and an integrated temperature transmitter can also be selected in the optional accessories.

The wall thickness of the wear-resistant thermocouple protection tube for cement plants is generally 4-8 mm (determined according to the temperature measurement location). This protection tube is specially designed for cement plants. Its function is to extend the service life of thermocouples at the temperature measurement points of C3, C4, C5, decomposition furnace, tertiary air duct, kiln tail smoke, and kiln head cover. When installing this product, you can leave a space or a protection tube on the kiln in advance according to the different industrial measurement and control points, and select a special thermocouple of corresponding specifications.

In the design process of this product, the specifications and models installed by the 1000-10000T/D cement production line in operation are fully considered for use at various measurement and control points on the production line.

Choice of protection tube length: insertion depth in the furnace + furnace wall thickness + exposed part outside the furnace = total length.

During the production operation, when installing or replacing the thermocouple, please slowly place the thermocouple into the furnace and fix the connecting device.

When the temperature at the process control point is measured at 1100℃ for a long time, the thermocouple works normally for about 60 working days. Because the thermocouple wire is in a high temperature state for a long time, its accuracy will change slightly. The temperature measuring element of the thermocouple can be replaced according to the process requirements.

After 60 working days of use of the thermocouple in places involving blanking or flushing, the thermocouple should be turned over at 90℃ and reinstalled to double the life of the special wear-resistant thermocouple.