Liquid relief valve in cylinder for compressor

Claim 1

In a rotary compressor having front and rear heads and a cylinder cooperatively defining a cylindrical pressure chamber having a circumferential side wall, a suction inlet opening to said chamber, a discharge outlet opening from said chamber at a position spaced circumferentially of said chamber from said inlet, and a rotor rotatably mounted in said chamber and having a one piece blade extending diametrically through said rotor engaging substantially opposite portions of the chamber side wall, means for alleviating an incompressible fluid block condition of the compressor wherein liquid fills a portion Of the chamber between the blade and a continuous portion of said chamber side wall free of said inlet and outlet openings, comprising: a relief passage opening from said chamber at said continuous portion of said chamber side wall; and check valve means permitting fluid flow only outwardly through said relief passage at a preselected high pressure above the normal maximum pressure of compressible fluid being compressed in said chamber by said compressor, whereby incompressible fluid trapped in said chamber portion is permitted to pass outwardly through said relief passage and compressible fluid compressed in said chamber portion is prevented from passing outwardly through said relief passage and caused to flow outwardly from said chamber through said outlet, said check valve means comprising a valve seat coaxially about said relief passage, a movable valve member seated on said seat and spring means in said relief passage biasing the movable valve member against said seat for closing the relief passage, and said relief passage comprisng a bore in said cylinder and an intersecting bore in one of said compressor heads, said pressure alleviating means further including means for retaining the biasing means in said relief passage comprising a hole in said cylinder extending between said front and rear heads and intersecting said relief passage, and a pin received in said hole and extending across said relief passage, whereby said pin is captured in said hole by said front and rear heads.