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Your location: Home > Related Articles > Interpretation of relevant principles of screw air compressors

Interpretation of relevant principles of screw air compressors

Author:QINSUN Released in:2023-06 Click:165

The twin-screw compressor was invented by the engineers of the Swedish company SRM in the 1930s. It was originally a twin-screw air compressor without oil.

Oil-injected twin screw compressors have been introduced to the market since the 1960s. After decades of development, they have become a widely used type of compressor.

The screw compressor head is mainly composed of a pair of male and female screw rotors and a crankcase with an \"8\" shaped internal cavity. The male and female screws mesh with each other and can be driven by each other under the action of the lubricating oil.

The convex teeth, grooves and housing of the male and female screw rotors form a working chamber. During the rotation of the rotor, the volume of the working chamber formed by the tooth groove and the housing changes from large to small, thus realizing the cogas pressure.

Do you know the basic principle of screw air compressor?

As a rotary displacement compressor, the screw compressor not only has the advantages of continuous gas transmission, good power balance and stable operation of the compressor rotary; Advantages of forced pumping by compressor type.

The volume flow of the screw compressor is hardly affected by the exhaust pressure, and it can maintain high efficiency in a wide range of working conditions.

Compared with the oil-free screw compressor, the oil-injected screw compressor sprays the lubricating oil directly during the compression process, and the lubricating oil directly participates to the air compression process, then the oil-gas separation device The lubricating oil and the compressed air are separated.

The lubricating oil has mainlythe following functions in oil-injected screw compressors:

1. Lubrication

Due to the lubricating effect of the oil lubrication, the female screw can be directly driven by the male screw. Compared with the oilless screw, a pair of synchronous gears can be reduced, which simplifies the structure of the main motor and reduces the cost.

2. Gasket

Due to the structural limitation of the screw compressor, there must be some space between the screw rotor and the crankcase, and the oil film formed by the lubricating oil can play a sealing role, reduce gas leakage between the rotor and the crankcase, and improve the compression efficiency.

At the same time, due to the sealing effect of the lubricating oil, the rotor speed can be greatly reduced and the requirements for machining accuracy of the rotor are also considerably reduced,thus reducing the processing cost of the rotor.

3. Clean

During the compression process, the lubricating oil can remove impurities from the compressed air and reduce wear of the rotor.

4. Anti-oxidation and anti-corrosion

The lubricating oil prevents screw rot or being oxidized and corroded by the water vapour, and reduces the requirements for the screw material.

In order to prevent oxidation and corrosion of the rotor by water vapor, the oil-free dry screw has a special coating on the surface of the rotor.

5. Cooling

The gas will be compressed during the compression processA large amount of heat is released, and the lubricating oil can absorb the major part of the heat during the compression process;

Thus, the oil-injected screw compressor can be controlled by controlling the amount and temperature of the oil injected into it.ns the temperature of the exhaust from the nose of the machine head.

If there is no coolant to absorb heat during the gas compression process, the single-stage pressure ratio of the screw compressor generally cannot reach than 3-4, and at this time, the temperature that the rotor can withstand the limit.

In addition, due to thermal expansion and contraction, the higher the temperature, the greater the consumption of labor.med in gas compression, and the greater the compression efficiency is low.

(In theory, the lower the temperature rise during the compression process, the higher the compression efficiency, i.e. isothermal compression allows to save labor) Therefore, the conventional exhaust pressure of 7-10 kg , the oil injection screw Compressor can achieve single-stage compression, while the vis dryer without oil should be divided into two stages.

Incorporating the above factors, the addition of lubricating oil greatly reduces the manufacturing and processing difficulty of screw compressors, which is why the price of screw compressors Oil-injected screw is much lower than that of oil-screw compressors without the reason.

Tag: screw air compressor