A cartridge mechanical seal for a process screw compressor

Abstract

The invention discloses a cartridge mechanical seal for a technological screw compressor, which comprises a sealing cavity and a shaft sleeve pierced through the inner cavity. A main seal and an auxiliary seal are respectively provided between the outside of the shaft sleeve and the interior of the sealing cavity. Seal, and the main seal and auxiliary seal are installed on both sides of the seal cavity in a back-to-back form along the axial direction, and the shaft sleeve, the seal cavity, the main seal and the auxiliary seal are integrated into one-piece structure; the seal cavity is close to the main seal There is also an accommodating cavity on one side of the accommodating cavity, and a lip seal assembly is arranged between the open end of the accommodating cavity and the outer side wall of the mounting boss at one end of the shaft sleeve, so that the accommodating cavity forms a first sealing cavity, which is used to prevent the process The process gas compressed in the compressor enters the working seal cavity of the mechanical seal. The cartridge mechanical seal for a technological screw compressor disclosed by the invention can better adapt to the working conditions of the technological screw compressor, and has more stable sealing performance and long service life.

Description

technical field [0001] The invention relates to the technical field of mechanical seals, in particular to a cartridge-type mechanical seal for technological screw compressors. Background technique [0002] Screw compressors have the advantages of centrifugal and piston compressors, while avoiding their disadvantages. This outstanding general adaptability makes them work well in the world from small chemical processes to large chemical plants. application. Therefore, process screw compressors are preferred in many chemical and petrochemical industry operations and processes, and oil-injected twin-screw compressors are ideal for process gases and applications due to their high reliability and low operating costs. [0003] Because the gas compressed by the process screw compressor is mostly process gas, it may contain toxic and harmful, flammable, explosive, and corrosive gases, so its compression chamber must be isolated from the atmosphere and bearings with shaft seals. [...

AI Technical Summary

Problems solved by technology

[0007] 2. Labyrinth seal: It has the advantages of simple structure and low cost, but it also has the disadvantages of short service life, large leakage (and gradually increases with the use time), high energy consumption (requires continuous ventilation and isolation) , under the increasingly stringent environmental protection requirements and energy-saving requirements, it is difficult for the labyrinth seal to meet the higher requirements for the use of process screw compressors. The proportion of its use is gradually decreasing, and it has reached a lower use level.

[0008] 3. Mechanical seal: Mechanical seal has the advantages of small leakage, long service life, energy saving and environmental protection, and simple maintenance, but it also has disadvantages such as relatively complicated structure, high cost of parts, high installation technical requirements, and lack of targeted design. However, compared with other shaft seals, there is a small amount of leakage and small shaft power consumption, which is in line with the current energy-saving and environmental protection requirements of the entire society. Mechanical seals have become the main shaft seal method for process screw compressors.

[0009] 3.1. Dry non-contact mechanical seal: the advantage is that the end face does not touch during operation, and there is no wear, so the service life is long and the leakage is small. The disadvantage is that the isolation gas must be continuously consumed, and the energy consumption is high, and it must be matched. The expensive auxiliary system itself is also very expensive to seal, and the cost performance is low

The disadvantage is that the theoretical service life is lower than that of dry gas seals, but it is far better than other forms of shaft seals. It is an ideal shaft seal solution for process screw compressors

However, since the working condition of the process screw compressor is a gas-liquid mixed state, mechanical seals are prone to dry friction, excessive wear, and severe heat generation, which restricts the application of wet contact mechanical seals in process screw compressors

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