Since the 1970s, the working reliability of screw compressors has been continuously improved, therefore, it is widely used in refrigeration and air-conditioning engineering in the range of medium refrigerating capacity, and depends on high reliability and efficiency, successfully squeezed into the original piston compressor dominated by the smaller cooling range (750 kw below) . Screw compressor has been so successful, let's analyze its performance.
(1) Screw compressor, simple and compact structure, less vulnerable parts, so long running cycle, convenient and reliable use, conducive to the realization of automation and unmanned operation.
(2)The screw compressor has the characteristics of forced gas transmission, which is little affected by pressure. In a wide range of work, can maintain a high level of efficiency.
(3) The screw compressor has the advantages of high rotating speed (usually above 3000r/min) , small volume, light weight, small occupation area and so on.
(4) Unlike a Reciprocating compressor compressor, which has no suction or exhaust valves, its compression structure is fairly simple in terms of the structural points and the robustness of the secondary compressors. All support points of the compressor is rolling, semi-sealed design, eliminate the design of the seal, and ensure gas leakage and free operation.
(5) The screw compressor has no reciprocating mass inertia force, good dynamic balance performance, and the foundation can be very small.
(6) Screw compressor is a rotary type of compressor, it does not have centrifugal or reciprocating compression mode. Compressed exhaust pressure vibration is very low, because when the screw rotation, recycling compression occurs on a week 6 vibration.
The screw compressor also has good thermal performance in the range of medium refrigerating capacity, and has good adjustment performance, can adapt to harsh operating conditions. At the same time, in order to ensure the normal operation of the screw refrigeration compressor, must be equipped with the corresponding auxiliary mechanisms, such as lubrication system, gas flow control device, safety protection device and monitoring instruments. Screw compressor has the advantage of high single-stage pressure ratio, but with the increase of pressure ratio, leakage loss also increases rapidly, low-temperature operation efficiency significantly reduced.
