How the compressor works

How the compressor works Screw compressors, also known as screw compressors, are divided into single screw compressors and twin screw compressors. The single-screw compressor was developed by Sinn of France in the 1970s. Because its structure is more reasonable, it is quickly applied to the field of national defense and protected by the developing country. The technology has always been relatively independent. The twin screw compressor was first proposed by the German H. Krigar in 1878. It was not until 1934 that the Swedish Royal Institute of Technology A. Lysholm laid the screw compressor SRM technology and began to apply it in industry, and achieved rapid development. Working principle of screw compressor The screw compressor cylinder is equipped with a pair of interlocking helical male and female rotors. Both rotors have several concave teeth, and the two rotate opposite to each other. The gap between the rotors and the casing and the rotor is only 5~10 filaments. The main rotor (also called the male rotor or the convex rotor) is driven by the engine or motor (mostly driven by the motor), and the other rotor (also called The female rotor or female rotor) is driven by the main rotor through the oil film formed by oil injection, or by the synchronous gears at the main rotor end and the female rotor end. So there is no metal contact in the drive (in theory). The length and diameter of the rotor determine the compressor displacement (flow rate) and discharge pressure. The longer the rotor, the higher the pressure; the larger the rotor diameter, the greater the flow. 02. Piston compressor ▼ The work of the piston compressor is completed by the working volume composed of the cylinder, the air valve and the piston reciprocating in the cylinder. If the volume loss and energy loss (that is, the ideal working process) of the actual operation of the piston compressor are not taken into account, the work completed by the piston compressor crankshaft every revolution can be divided into suction, compression, and exhaust processes. Working principle of piston compressor Compression process: The piston moves upward from the bottom dead center, the suction and exhaust valves are closed, and the gas is compressed in the closed cylinder. As the cylinder volume gradually decreases, the pressure and temperature gradually increase until the gas pressure and exhaust in the cylinder The pressure is equal. The compression process is generally regarded as an isentropic process. Exhaust process: The piston continues to move upwards, so that the gas pressure in the cylinder is greater than the exhaust pressure, the exhaust valve opens, and the gas in the cylinder is pushed out of the cylinder by the piston to enter the exhaust pipe at equal pressure until the piston moves to the top stop point. At this time, due to the spring force of the exhaust valve and the gravity of the valve disc itself, the exhaust valve is closed and the exhaust is ended. 03 Centrifugal compressor ▼ Centrifugal compressors, also known as turbine compressors, are mainly used to compress gas. They are mainly composed of a rotor and a stator: the rotor includes an impeller and a shaft, and the impeller has blades, a balance disk, and a part of the shaft seal; the main body of the stator is a cylinder There are also diffusers, bends, recirculators, air pipes, exhaust pipes and other devices. Working principle of centrifugal compressor When the impeller rotates at high speed, the gas rotates with the centrifugal force, and the gas is thrown into the diffuser behind, and a vacuum zone is formed at the impeller. At this time, fresh gas from the outside enters the impeller. The impeller continuously rotates, and the gas is continuously sucked in and thrown out, thereby maintaining the continuous flow of gas. 04 Rotor compressor ▼ The rotor compressor is driven by the engine or the motor (mostly driven by the motor), and the other rotor (also called the female rotor or the concave rotor) is driven by the oil film formed by the main rotor through oil injection, or by the main rotor end and the concave rotor end. Synchronous gear drive. Rotor compressor principle 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 to form a compression chamber. When the rotor groove is closed, lubricating oil is sprayed into the compression chamber to seal. Cooling and lubrication. When the rotor rotates to compress the lubricant + gas (referred to as the oil-air mixture), the volume of the compression chamber decreases, and the oil-air mixture is compressed toward the exhaust port. When the compression chamber passes through the exhaust port, the oil-gas mixture is discharged from the compressor, completing an intake-compression-exhaust process. 05 Axial compressor ▼ Axial compressor is a large-scale air compressor, the maximum power can reach 150,000KW, the displacement is 20000 cubic meters/minute, and its compressor energy efficiency ratio can reach about 90%, which is more energy saving than centrifuge . Axial compressors and centrifugal compressors are both speed type compressors and are called turbo compressors. The meaning of speed compressors is that their working principle relies on the blades to work on the gas, and the flow speed of the gas can be greatly improved first, and then the kinetic energy is converted into pressure energy. The meaning of turbine compressors is that they all have blades rotating at high speed. 06 sliding vane compressor ▼ The vane compressor is directly driven at a very low speed. The rotor is the only part that runs continuously. There are several slots cut along the length direction, in which there are inserted sliding sheets that can slide on the oil film. The rotor is in the stator of the cylinder Rotate. Working principle of sliding vane compressor Air is sucked in through a filter and a regulating proportional valve. The regulating valve is mainly used to regulate the pressure chamber formed by the rotor and slide of the air cylinder. The rotor rotates eccentrically with respect to the cylinder, the valve plate is installed in the rotor groove, and the slider is pushed to the cylinder wall by centrifugal force. The efficient oil injection system can ensure the cooling of the compressor and the minimum loss of lubricant. A thin oil film formed on it can prevent direct contact between metal parts and cause wear.