How to distinguish between screw refrigeration compressor and piston refrigeration compressor Distinguish from type

How to distinguish between screw refrigeration compressor and piston refrigeration compressor Distinguish from type

　　 Screw refrigeration compressor and piston refrigeration compressor are both positive displacement compressors, and screw refrigeration compressor is a new type of high-speed refrigeration compressor.

　　 distinguish in principle

　　 From the point of view of the principle of compressing gas, the two compressors have the same point that the gas is compressed by the change of volume; the difference is that the two types of compressors have different ways to achieve the change of working volume. The piston refrigeration compressor changes the working volume of the cylinder by the movement of the crankshaft connecting rod mechanism; the screw refrigeration compressor changes the working volume by the rotation of the rotor directly connected to the shaft.

Distinguish from the overall structure

Screw refrigeration compressors do not have the cylinders, pistons, piston rings, cylinder liners and other vulnerable parts required by piston refrigeration compressors. The machine is compact in structure, small in size, light in weight, and has no clearance volume. A small amount of liquid will not enter the machine. Danger of liquid shock. The live valve can be used for stepless energy adjustment of 10% to 100%. It has a wide range of applications, stable and reliable operation, long maintenance period, and trouble-free operation time up to (2～5)×104h. The use of lubricating oil improves the cooling and sealing performance of the machine and reduces the exhaust temperature. Even if the evaporation temperature is low (-40°C) and the compression ratio is high (about 25), it can still operate in a single stage, that is, within a certain range It can replace the two-stage compression cycle. However, screw-type refrigeration compressors require high precision in processing and assembly, and are not suitable for variable working conditions. They have greater noise. Under normal circumstances, noise reduction and sound insulation equipment must be installed. During refrigeration and compression, spraying is required. Lubricating oil requires many auxiliary equipment such as oil pump, oil cooler and oil recovery device.

　　In recent years, the screw compressor with adjustable internal volume ratio has been developed, and the adjustable range is 2.6～5, which further improves the performance of screw compressor. Recently, a new type of semi-closed screw machine has been developed in China, which adopts a new 5:6 asymmetric tooth profile, which greatly improves the volumetric efficiency. The operating economy, reliability and service life of the new screw refrigeration compressor have exceeded that of the piston refrigeration compressor. Therefore, full attention should be paid to the design and selection of refrigeration equipment.