The screw chiller is mainly composed of screw compressor, condenser, evaporator, expansion valve and electric control system.​
(1) Twin screw compressor
The twin-screw refrigeration compressor is an energy-adjustable oil-injected compressor. Its three continuous processes of suction, compression and exhaust are realized by the periodic volume change generated by a pair of intermeshing yin and yang rotors in the body. Generally, the male rotor is the active rotor, and the female rotor is the driven rotor.
Main components: double rotor, body, main bearing, shaft seal, balance piston and energy adjustment device.
The capacity is 15-100% stepless adjustment or two- or three-stage adjustment, and the hydraulic piston is used to increase and decrease the load. Conventional use:
Both the radial and axial directions are rolling bearings; the open type is equipped with an oil separator, an oil storage tank and an oil pump; the closed type is used for differential pressure oil supply for lubrication, oil injection, cooling and driving the piston movement of the spool valve capacity adjustment.
Compression principle:
Inhalation process: the gas enters the interdental volume of the yin and yang rotors respectively through the air inlet.
Compression process: When the rotor rotates, the volume between the yin and yang rotor teeth is connected (V-shaped space). Due to the meshing of the teeth, the volume is gradually reduced, and the gas is compressed.
Exhaust process: The compressed gas is moved to the exhaust port to complete a working cycle.
(2) Single screw compressor (single screw compressor)
Compression is produced by the meshing of an active rotor and two star wheels. Its three continuous processes of suction, compression and exhaust are realized by the periodic volume change when the rotor and the star wheel rotate.
The rotor has six teeth and the star wheel has eleven teeth.
The main components are a rotor, two star wheels, a body, a main bearing, and an energy regulating device.
The capacity can be infinitely adjusted from 10%-100% and adjusted in three or four stages.
Compression principle:
Suction process: the gas enters the rotor slot through the suction port. With the rotation of the rotor, the star wheel enters the state of meshing with the rotor cogging in turn, and the gas enters the compression cavity (the closed space formed by the rotor cogging surface, the inner cavity of the casing and the tooth surface of the star wheel).
Compression process: As the rotor rotates, the volume of the compression chamber decreases continuously, and the gas is compressed until the front of the compression chamber transfers to the exhaust port.
Exhaust process: After the front edge of the compression chamber turns to the exhaust port, the exhaust starts to complete a working cycle. Due to the symmetrical arrangement of the star wheels, the cycle undergoes two compressions per revolution, and the displacement is correspondingly twice that of the above cycle.

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