Analysis of the structural principle and advantages of screw compressors

The working cycle of a screw compressor can be divided into three processes: suction, compression and exhaust. As the rotor rotates, each pair of mutually meshing teeth completes the same work cycle one after another.

Compression during suction process and exhaust process during fuel injection

1) Inhalation process: When the rotor rotates, the tooth groove space of the main and auxiliary rotors has the largest space when it is turned to the opening of the inlet end wall. At this time, the tooth groove space of the rotor is in communication with the free air at the air inlet. , The outside air is sucked into the enclosed cavity composed of the yin and yang rotor and the shell. When the air fills the entire tooth groove, the air inlet end face of the rotor turns away from the air inlet of the casing, and the air between the tooth grooves is closed.

2) Compression process: As the rotor rotates, the volume between teeth decreases continuously due to the meshing of the rotor teeth. The volume occupied by the gas enclosed in the volume between the teeth also decreases, resulting in an increase in pressure, thereby realizing the compression process of the gas. The compression process can continue until the inter-tooth volume is just before communicating with the exhaust port.

3) Exhaust process: When the enclosed volume between the teeth is connected to the exhaust port, the compressed gas begins to discharge. As the volume between the teeth continues to decrease, the compressed gas is completely discharged.

The advantages of screw compressors:

1) Screw compressors are the same as piston compressors and are both positive displacement compressors. In terms of the use effect, the screw air compressor has the following advantages.

2) High reliability. The screw compressor has few parts and no wearing parts, so it runs reliably and has a long life. The interval between overhauls can reach 40,000 to 80,000 hours.

Easy to operate and maintain. The screw compressor has a high degree of automation, and the operator does not need to go through long professional training, and can realize unattended operation.

3) Good power balance. The screw compressor has no unbalanced inertial force, the machine can work steadily and at a high speed, and can realize no foundation operation. It is especially suitable for mobile compressors, with small volume, light weight and less floor space.

4) Strong adaptability. The screw compressor has the characteristics of forced air delivery, the volume flow is almost not affected by the exhaust pressure, and it can maintain high efficiency in a wide range. It is suitable for a variety of working conditions without any changes to the compressor structure.