Novel interstage air supplementing device of multi-stage compression centrifugal type refrigeration compressor

The invention discloses a novel interstage air supplementing device of a multi-stage compression centrifugal type refrigeration compressor. The air supplementing device is characterized in that a second-stage exhaust volute (19) is arranged in a casing (1); a first-stage suction guiding ring (11), a first-stage impeller (5), a second-stage impeller (10) and an impeller distance ring (8) are arranged on a transmission shaft (9); a second-stage suction passage (15) is arranged in an interstage baffle (3); a first-stage exhaust passage (14) is formed between a first-stage diffuser (2) and the interstage baffle (3) in the casing (1); a second-stage exhaust passage (17) is formed between the interstage baffle (3) and the second-stage impeller (10); the casing (1), the first-stage diffuser (2) and the interstage baffle (3) commonly form an air supplementing and supplying passage (20); a straight slot section (18) is formed between the first-stage diffuser (2) and the interstage baffle (3); and an inter-stage sealing ring (7), a first-stage wheel cover sealing (4) and a second-stage wheel cover sealing (6) are arranged. By the device, the interstage air can uniformly enter a reflux apparatus of the compressor; the efficiency of the compressor is improved; and the airflow noise of the compressor is reduced.