Semi-closedscrew compressor

The utility model provides a semi-closedscrew compressor. The semi-closedscrew compressor comprises a compressor body, a sliding valve, a sliding valve rod and an oil piston, wherein the compressor body comprises a sliding valve cavity, an oil piston cavity and a baffle for separating the sliding valve cavity from the oil piston cavity; a middle through hole is formed in the baffle; the semi-closedscrew compressor further comprises a middle supporting sleeve; the middle supporting sleeve is arranged on the middle through hole in a matchingway; the middle supporting sleeve is provided with a sliding valve rod hole; the sliding vale is arranged in the sliding valve cavity; the oil piston is arranged in the oil piston cavity; the sliding valve rod penetrates through the sliding valve rod hole; the two ends of the sliding valve rod are respectively connected with the sliding valve and the oil piston. According to the semi-closedscrew compressor, by arranging the middle supporting sleeve on the middlethrough hole of the baffle, the middle of the sliding rod is supported, the gravity of the sliding valve is balanced, the pressure on the sliding valve cavity by the sliding valve is reduced, the abrasion of the sliding valve during motion is reduced, clamping is prevented, and the service life of the sliding valve is effectively prolonged.