A rotary rolling piston compressor having a hermetic shell in which a cylinder is fixedly mounted. A rolling piston is driven by a crankshaft supported by a bearing pair and carried by the rotor of an electric motor whose stator is fixed internally to the shell. The cylinder has a radial slot in which a vane reciprocates. The vane defines compression and suction chambers, limited axially by the internal faces of the bearings and the chambers having discharge and suction orifices, respectively. The internal face of at least one of the bearings is provided with a groove with one end in communication with the compression chamber and the part on the suction chamber side of the vane in communication with a recess provided on the radial slot surface, on the suction chamber side. The recess extends transversely to the direction of the reciprocating displacement of the vane. This arrangement causes the compression chamber pressure to be transmitted to the vane face turned to the suction chamber, while lubrication of this same side of the vane with the oil held within the groove and coming from the compression chamber is promoted.

A discharge flow blocking valve for a compressor having a sealed housing having a cylinder and a piston for compressing refrigerant gas. A discharge muffler is within the housing and has an inlet opening communicating with the cylinder discharge volume, a first outlet opening communicating with the interior of the sealed housing, and a second outlet opening. The blocking valve has an outer casing with a first driving opening in communication with said second outlet of said discharge muffler, and a second driving opening in communication with the housing interior, an inlet in communication with the interior of the housing and an outlet in communication with a discharge mean extending through the housing. A piston movable within the valve casing has surfaces communicating with and responsive to the gas pressure at said first and second driving inlets and is responsive to a pressure differential between the gases at said first and second driving inlets when the compressor starts and the pressure of the second outlet of the muffler is greater than that in the housing interior for moving the piston to provide fluid communication between the valve casing inlet and outlet openings so that the refrigerant gas can leave the compressor, the valve piston being moved to a position to close the valve when the compressor stops and the pressure in the discharge muffler drops.

An outlet valve for rotary rolling piston compressor, the piston being assembled within a cylinder block having an attached end wall provided with gas discharge passage whose outlet end defines an annular valve seat placed in an oblong recess area circumscribing the valve seat within which a valve blade is located, the area between the bottom wall with the circumscribing side wall of the oblong recess and/or with the peripheral wall of the valve seat being curved to reduce the turbulence of gas leaving the outlet of the discharge passage.