The cylinder of the screw compressor is equipped with a pair of spiral rotor meshing with each other, both rotors have several concave teeth, and the two rotate opposite to each other. The gap between the rotor and the shell and the rotor is only 5 to 10 wires, the main rotor (also known as the positive rotor or convex rotor), by the engine or motor drive (mostly motor drive), the other rotor (also known as the negative rotor or concave rotor) is driven by the oil film formed by the main rotor through the injection of oil, or by the main rotor end and the concave rotor end synchronous gear drive. So there is no metal contact in the drive (theoretically).
The length and diameter of the rotor determine the compressor exhaust volume (flow) and exhaust pressure, the longer the rotor, the higher the pressure; The larger the rotor diameter, the greater the flow rate.
The spiral rotor groove is filled with gas as it passes through the intake port. When the rotor rotates, the rotor groove is closed by the casing wall to form a compression chamber. When the rotor groove is closed, the lubricating oil is sprayed into the compression chamber to seal. Cooling and lubrication. When the rotor rotates to compress lubricant + gas (referred to as oil-gas mixture), the volume of the compression chamber is reduced, and the oil-gas mixture is compressed to the exhaust port. When the compression chamber passes through the exhaust port, the oil and gas mixture is discharged from the compressor, completing an aspiration-compression-exhaust process. Each rotor of the screw machine is supported by an antifriction bearing, which is fixed by an end cap near the end of the rotating shaft. The intake end is supported by a roller bearing, and the exhaust end is supported by an opposing cone roller. Usually the exhaust end bearings position the rotor, that is, thrust bearings, resist axial thrust, bear radial loads, and provide the minimum clearance necessary for axial operation.
The working cycle can be divided into three processes: suction, compression and exhaust. As the rotor rotates, each pair of meshing teeth successively completes the same working cycle.
