Abstract: An unloader apparatus for a gas compressor having a compressor cylinder and a reciprocating compressor piston slidable in the compressor cylinder. The unloader apparatus comprises a hollow sleeve positioned in a suction line of the gas compressor with a port therethrough for communicating gas from the suction line to a suction valve. An unloader piston is slidably disposed within the hollow sleeve and is movable between an open position opening the port whereby gas flow to the suction valve is prevented and a closed position closing the port. In its closed position, the unloader piston seals the compressor cylinder and the compressor piston reciprocates in a partial vacuum. Actuating means connected to the unloader piston is provided for moving the piston between its respective positions. The actuating means utilizes high pressure gas from the discharge side of the compressor for sliding the unloader piston between its positons and exhausts the gas to the suction side of the compressor.

Abstract: A valve for compressor clearance or by-pass control for a gas compressor having a compressor cylinder which includes a tubular member having a bore communicating with the compressor cylinder, an outer surface and an opening. A valve sleeve receives the tubular member therein and is slidably movable with respect thereto between an open position whereat one of a clearance pocket and a suction chamber communicates with the compressor cylinder through the opening and a closed position closing the opening. A plug is positioned in the tubular member bore and reduces the amount of clearance in the compressor cylinder. Actuator means is provided for moving the valve sleeve between its open and closed positions. The tubular member is attached to an outboard side of a suction valve assembly, and the bore thereof communicates with a passage extending through the suction valve assembly and opening into the compressor cylinder.

Abstract: A valve assembly and a valve member therefor including a fluid passage in the valve assembly with inlet and outlet portions and a valve seat. The valve member includes a valve member face selectively engaging the valve seat and defining a contact area therebetween with an inlet peripheral edge adjacent the passage inlet portion, and an outlet peripheral edge adjacent the passage outlet portion. An inlet pressure relief groove extends along one of the valve seat and the valve member face from the inlet peripheral edge to an interior portion of the contact area. An outlet pressure relief groove extends along one of the valve seat and the valve member face from the outlet peripheral edge to an interior portion of the contact area. The contact area includes a continuous sealing portion whereat the valve seat and the valve member face are in engagement for preventing fluid flow from the passage inlet portion to the passage outlet portion with the valve member in its closed position.

Abstract: A valve assembly for controlling the flow of fluid, has a passage for fluid flow therein and open and closed positions whereby fluid flow through said passage is respectively allowed and prevented. First and second mating surfaces define a contact area therebetween when the valve assembly is in its closed position. Relief means is provided for communicating fluid from the passage with an inner portion of the contact area for operably reducing a force required to disengage the mating surfaces and open the valve assembly.

Abstract: A screw locking arrangement comprises an article having a threaded aperture with an enlarged counterbore. A slot is positioned in the side wall of the counterbore and extends through the top surface of the article. A screw is threadedly engaged in the aperture and includes an enlarged head with a slot disposed in the outer marginal surface thereof. A deformable lock member is positioned in the counterbore and has a wall between the counterbore side wall and the marginal surface of the screwhead, and the wall is bent by a suitable tool into both of the slots, thereby positively locking the screw and the article together without indexing the same.

Abstract: An unloader assembly for a gas compressor having a compressor suction chamber and a compressor cylinder with a compressor piston slideable therein for effecting one-way gas flow through a suction valve assembly mounted in the compressor suction chamber, said suction valve assembly having a central passage therethrough. An unloader piston is slideably movable in the central passage of the suction valve between a first position closing a plurality of ports in the suction valve each providing communication between the suction chamber and the suction valve central passage and a second position opening the ports. A clearance bottle is mounted on the compressor and a valve controlled aperture permits communication between the suction chamber and the clearance bottle until closed by a clearance bottle valve.