VANE BACK PRESSURE CONTROL STRUCTURE IN SLIDING VANE COMPRESSOR

PURPOSE:To prevent the breakdown of parts such as a rotor, a vane and the like when liquid compression happens as well as to improve the durability of a compressor, by setting a formation range for an intermediate pressure groove for the purpose of interconnection between the intermediate pressure groove and a vane back pressure chamber. CONSTITUTION:As shown in illustration, formed in front of a rear side plate, a semicircular intermediate pressure groove 28 interconnecting a compression chamber 17 starts its interconnection with a back pressure chamber 15a when the tip of a vane 16' is shifted to a position C at the initial stage of suction stroke, and this is formed so as to cause the back pressure chamber 5a of the succeeding vane 16' to separate from the intermediate pressure groove 28 when the compression chamber 17 formed by the vane 16' and a vane 16 going a head of the vane 16' is interconnected with a discharge port 19. With this, even when liquid compression happens in the compression chamber 17, pressure in the compression chamber 17 escapes to a discharge port 20 via the discharge port 19 whereby the compression chamber 17 will not come into a state of being unusual high pressure, thus the breakdown of related parts can be prevented.