Do you know several common refrigeration compressors?

1. Semi-sealed piston refrigeration compressor

Among all kinds of refrigeration compressors, piston compressor is the earliest one and is still widely used up to now. For example, semi-closed piston refrigeration compressor is widely used in refrigeration equipment. Common manufacturers are: Emerson, Biesel, Sanyo, Duling and other compressors.

Characteristics of semi-closed piston refrigeration compressor: wide energy pressure range and refrigeration capacity, low material requirements, mature technology, simple compressor system, but very afraid of liquid impact.

There are two common failures of semi-closed piston refrigeration compressor: mechanical failure and electrical failure.

Common mechanical failures are abrasion or damage of connecting rod, crankshaft and valve plate; Electrical faults are mainly short circuit, open circuit and burning of motor windings.

2. Double-rotor refrigeration compressor

Double-rotor compressors are widely used in household appliances, and the export scale of rotary compressors is increasing year by year, with a compound annual growth rate of 12.8% from 2009 to 2019. Now, many air-conditioning equipment choose double-rotor compressors with less than 7 pieces.

Characteristics of rotary compressor: few parts and simple structure. Less vulnerable parts, reliable operation. There is no suction valve, so the clearance volume is small, the gas transmission coefficient is high, the machining accuracy is high, the sealing performance is poor and the leakage loss is large.

The advantages of double-rotor compressor are: good low-frequency energy efficiency ratio, lower high-frequency energy efficiency ratio than scroll, slightly larger noise, vibration and wear than scroll, shorter service life than scroll, and difficult to make large displacement. The advantages of scroll compressor are: low-frequency energy efficiency ratio is general, high-frequency energy efficiency ratio is better than scroll, noise and vibration are small, wear and tear are long, and large displacement can be achieved.

3. Scroll refrigeration compressor

The scroll compressor is mainly composed of a moving disk (scroll rotor), a stationary disk (scroll stator), a bracket, a cross coupling ring, a back pressure cavity and an eccentric shaft. It can be divided into low-pressure cavity compression and high-pressure cavity.

The low-pressure cavity compressor shows that the whole shell is low temperature, and the inside of the shell cavity (except the exhaust port and exhaust cavity) is low pressure; The high-pressure cavity compressor shows that the whole shell is at high temperature, and the inside of the shell cavity (except the suction port and suction cavity) is at high pressure.

Features of scroll compressor: stable operation, small vibration, quiet working environment, few vulnerable parts, stable operation, low noise, long service life and high EER value, which are used in refrigeration and air conditioning systems.

4. Screw refrigeration compressor

Screw refrigeration compressor is mainly composed of casing, rotor, bearing, shaft seal, balance piston and energy regulating device. Screw refrigeration compressor has two screws with spiral tooth grooves meshing and rotating, which causes the change of the volume between the teeth, thus completing the process of suction and compressor, and the cooling capacity can be adjusted infinitely between 10% and 100%. Screw refrigeration compressor is widely used in refrigeration and HVAC equipment.

Characteristics of screw refrigeration compressor: the strength and wear resistance of rotor and bearing are relatively high; The exhaust volume is almost unaffected by the exhaust pressure; Maintain high efficiency in a wide range of working conditions; It can realize stepless adjustment of energy and is insensitive to incoming liquid, but a large amount of returning liquid will also cause compressor failure.

5. Centrifugal refrigeration compressor

Centrifugal refrigeration compressor belongs to speed compressor, which is a kind of machinery with rotary impeller. It relies on high-speed rotating impeller to do work on gas to improve the pressure of gas. Almost all refrigeration compressors with a single machine capacity of more than 1200kW adopt centrifugal refrigeration compressors, and generally centrifugal compressors are used in large and extra-large air-conditioning equipment.

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Characteristics of centrifugal refrigeration compression: good dynamic balance and small vibration; Less wear parts, long continuous operation period; It is easy to realize multi-stage compression and throttling and realize various evaporation temperatures; It can carry out stepless adjustment economically; When the cooling capacity is small, the efficiency is low; Easy to surge.