What is a compressor?

A compressor, a driven fluid machine, can raise low-pressure gas to high-pressure. It is the heart of the refrigeration system. It sucks in low-temperature and low-pressure refrigerant gas from the suction pipe, compresses it by the motor driving the piston, and then discharges the high-temperature and high-pressure refrigerant liquid to the exhaust pipe to provide power for the refrigeration cycle, thereby achieving compression → Condensation → Expansion → Transpiration (heat absorption) refrigeration cycle.

Compressors are divided into piston compressors and screw compressors.

Generally speaking, a compressor consists of a casing, a motor, a cylinder, a piston, control equipment (starter and thermal protector) and a cooling system. There are two cooling methods: oil cooling and natural cooling.

Generally, the compressors of household refrigerators and air conditioners are powered by single-phase alternating current, and their structural principles are basically the same. They use different refrigerants.

Compressors can be divided into positive displacement compressors and speed compressors according to their principles. The volume is divided into reciprocating compressor and rotary compressor. Speed ​​compressors are divided into axial compressors and centrifugal compressors.

At present, household refrigerators and air-conditioning compressors are of positive displacement type, divided into reciprocating type and rotary type. Reciprocating compressors use piston, crank and connecting rod mechanism or piston, crank, sliding tube mechanism, and most of them now use rotary compressors. Commercial air conditioners are mostly centrifugal, scroll, and screw types.

According to the scale of use, it can be divided into low back pressure type, medium back pressure type and high back pressure type. Low back pressure type (transpiration temperature -35~-15℃), generally used in household refrigerators, food freezers, etc. Medium back pressure type (transpiration temperature -20~0℃), generally used in cold drink cabinets, milk freezers, etc. High back pressure type (evaporating temperature -5~15℃), generally used in room air conditioners, dehumidifiers, heat pumps, etc.