Several sealing devices commonly used in rotary kiln Henan Hongxing


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Several sealing devices commonly used in rotary kiln at present

Rotary kiln It is the key production equipment in alumina, cement, chemical and metallurgical industries. Rotary kiln is operated under negative pressure. If excessive air is leaked into the hot end, the secondary air into the kiln will be reduced, and the amount of secondary air will be reduced, resulting in heat loss. In the operation process of rotary kiln, the sealing quality of rotary kiln is of great significance to the whole process parameters of clinker burning and efficient operation of equipment. Under complex process conditions, the sealing should have the following characteristics: no air leakage, no ash leakage, no material leakage, high temperature resistance, wear resistance, long life, high reliability, easy installation and maintenance. At present, there are several sealing devices commonly used in rotary kiln.

 Rotary kiln

1) Labyrinth sealing device

Labyrinth seal device is divided into axial labyrinth and radial labyrinth. The structure of the device is relatively simple, there is no contact surface, there is no wear problem, at the same time, the impact of simple channeling. The thermal expansion, cold contraction, bending and radial runout of the cylinder are considered. Labyrinth seal in both radial and axial clearance can not be too small, so, labyrinth seal also has its shortcomings, that is, the seal is not ideal, there is air leakage, leakage of materials and other situations. Therefore, it is only suitable for small pressure occasions or combined with other seals.

2) Friction sealing device

The friction sealing device is mainly divided into radial friction type and axial friction type, which is better and more universal. The radial contact friction seal is graphite block seal. There are two forms of graphite block around the kiln body. One is to compact the heavy hammer and steel wire rope tightly, and contact the sleeve tightly without leaving any gap. The other is to fix it with the sleeve by spring. This form is not suitable for high temperature. The graphite block sealing structure has the advantages of self lubrication, low friction power consumption, not easy to wear, and simple structure.

The axial friction seal is the cylinder compression face seal and the spring leaf compression end face friction. The structure of this device is relatively complex, and the maintenance is inconvenient. If the spring is overheated, it will lose its elasticity, thus the desired seal can not be achieved,

3) Gas seal device

This device can be divided into positive pressure and negative pressure sealing. The main principle is to form air pressure outside with the help of external gas, so that the gas inside will not overflow due to pressure. The wear rate of this structure is small, but it is difficult to control the inflow of gas. If there is cold air leakage, it will have a negative impact on the process operation.

4) Combined sealing device

The combined seal is mainly the combination of labyrinth seal and fish scale seal. Its main feature is the contact seal between the fixed top metal scale and the friction ring. This kind of seal is a more advanced and better sealing form at present. However, due to some special reasons, such as poor state of kiln body, bending of kiln line, instability, etc., it is found that the fish scales contacting with the kiln body are easy to be damaged and can not be used normally, so only its labyrinth structure is left, which can not guarantee the combined sealing.

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