The cylinder of the screw compressor is equipped with a pair of helical male and female rotors that mesh with each other. Both rotors have several concave teeth and rotate in opposite directions to each other. The gap between rotors and between the casing and rotors is only 5-10 threads. The main rotor (also known as the male rotor or convex rotor) is driven by the engine or electric motor (mostly electric motor), while the other rotor (also known as the female rotor or concave rotor) is driven by the oil film formed by the main rotor through fuel injection, or by the synchronous gear between the main rotor end and the concave rotor end. So there is no metal contact in the drive (theoretically). The length and diameter of the rotor determine the displacement (flow rate) and discharge pressure of the compressor. The longer the rotor of an industrial chiller, the higher the pressure; The larger the rotor diameter, the greater the flow rate. The spiral rotor groove is filled with gas when passing through the suction port. When the rotor rotates, the rotor groove is closed by the casing wall, forming a compression chamber. After the rotor groove is closed, lubricating oil is sprayed into the compression chamber to seal it. Cooling and lubrication effects. When the rotor rotates and compresses the lubricant+gas (referred to as the oil gas mixture), the volume of the compression chamber decreases, and the oil gas mixture is compressed towards the exhaust port. When the compression chamber passes through the exhaust port, the oil and gas mixture is discharged from the compressor, completing a suction compression exhaust process. Each rotor of the screw machine is supported by anti friction bearings, which are fixed by end caps near the end of the shaft. The intake end is supported by roller bearings, while the exhaust end is supported by a pair of tapered roller bearings. The exhaust end bearings are usually used to position the rotor, that is, thrust bearings, resist axial thrust, bear radial loads, and provide the necessary minimum clearance 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 completes the same working cycle one after another. The advantages of the compressor for screw chillers are: 1. Both screw compressors and piston compressors belong to positive displacement compressors. From the perspective of usage effect, screw air compressors have the following advantages. 2. High reliability. The chiller compressor has few components and no vulnerable parts, so it operates reliably and has a long service life. The overhaul interval can reach 40000 to 80000 hours. 3. Easy to operate and maintain. The low-temperature chiller has a high degree of automation, and operators do not need to undergo long professional training, allowing for unmanned operation. 4. Good power balance. The refrigeration machine has no unbalanced inertia force, and can work smoothly and at high speed without any foundation. It is particularly suitable for use as a mobile compressor, with small size, light weight, and small footprint. 5. Strong adaptability. Screw compressors have the characteristic of forced gas delivery, and their volumetric flow rate is almost unaffected by exhaust pressure. They can maintain high efficiency over a wide range and are suitable for various working conditions without any changes to the compressor structure.