Blade-type rotary compressor with full unloading and oil sealed interfaces

In a rotary compressor having a body with a cylindrical bore, end caps at opposite ends of said body, a rotor eccentrically mounted within said bore, said rotor substantially engaging said bore along a seal line, means for driving said rotor, said rotor having a plurality of radial grooves extending the entire length, a blade slidably mounted in each groove, said blades cooperating with said bore, said end caps and said rotor to define a plurality of compression pockets, said body having a fluid inlet opening on one side for introducing fluid to be compressed into said compression pockets and a discharge opening remote from said inlet opening for discharging compressed fluid from said body, means for driving said rotor in a direction from said inlet opening toward said discharge opening, the area between said inlet and discharge openings in the direction of rotation of said rotor defining the compression side of said compressor, the improvement comprising, each of said end caps having an elongated arcuate channel extending throughout its length adjacent to the discharge opening of said body, and means for introducing oil under pressure greater than the pressure created within the compression pockets into an inlet end of said channel, said inlet end of said channel being located at the beginning of the discharge opening outwardly of the inner side edge surfaces of the blades and spaced inwardly from the periphery of said rotor, said channel curving outwardly along the discharge opening and terminating adjacent to the periphery of said rotor substantially at said seal line adjacent the end of the discharge opening.