The air compressor is called a screw air compressor, which is a volume air compression machine with working volume for rotary motion. The compression of gas is realized by the change of volume, which is achieved by the rotary motion of a pair of rotors in the compressor shell.
The working principle of screw air compressors is that the working cycle of a screw compressor can be divided into three processes: the air intake, compression and exhaust processes. As rotors rotate, each pair of meshing teeth successively completes the same working cycle.
1. The intake process: When rotors rotate, the space of the tooth groove of the Yin and Yang rotors is the largest in space when they turn to the opening of the intake wall. At this point, the rotor groove space interconnects with the intake port, because the gas in the tooth groove is completely discharged during the exhaust. When the exhaust is completed, the tooth groove is in a vacuum state. When the grove is turned to the intake entry, the external gas is inhaled and enters the tooth groove of the Yin and Yang rotors along the axial direction. When the gas fills the whole groove, the end of the rotors is turned away from the air inlet of the casing, and the gas in the tooth groove is closed.
2. The compression process: When the Yin and Yang rotors are at the end of suction, their tooth tips will be closed with the casing. At this time the gas no longer outflows in the teeth. The meshing surface gradually moves to the exhaust end. The tooth groove space between the meshing surface and the exhaust port becomes gradually smaller, and the gas in the tooth furrow is increased by the compression pressure.
3. The exhaust process: When the rotor's meshing end is connected with the exhaust port of the casing, the compressed gas starts to be discharged until the meshing surface of the tooth tip and the gear groove moves to the exhaust end. At this time, the space between the meshing surface of the Yin and Yang rotors and the exhaust port of the engine shell is zero. That means the exhaust process is completed. At the same time, the length of the tooth groove between the meshing surface of the rotor and the air inlet of the casing is the longest, and the intake process will carried out again.