SCREW COMPRESSOR Russian patent published in 1999 - IPC

FIELD: manufacture of compressors. SUBSTANCE: rotors are formed by single-start and double-start threads with two first turns performing function of forming closed cavity between them at suction and compressing turns which are used to compress gas in their inter-turn cavities. Number of compressing turns depends on relation of geometric degree of compression of compressor to permissible geometric degree of compression in inter-turn cavity of compressing turns. Angle of helix of forming turns decreases continuously and angle of helix of compressing turns increases continuously in way of thread towards delivery. Rotor with screw portion provided with helical grooves is thrown into engagement with rotors whose screw portions are provided with projecting turns whose number ranges from one to four per rotor and screw portion is provided with helical grooves. Each rotor has two screw portions at distance from each other; they are in placed anti-phase. EFFECT: increased productivity; simplified tooth profile; reduced level of noise. 4 cl, 4 dwg