Rotary vane compressor with outlet pressure biased lubricant

Abstract

A rotary vane compressor in which the pressure difference between inlet and outlet passages is utilized to accomplish lubrication without a supplementary oil pump comprises a housing with a cylindrical bore, a hollow rotor eccentrically rotatable on a shaft in the bore and at least one vane radially slidable in a slot in the rotor and sealingly engaging with the inner surfaces of the bore to define fluid chambers of varying volume. The compressor further has inlet and outlet passages communicating with the bore and an oil sump disposed below the bore. A first passageway connects the outlet passage with the sump, and the hollow of the rotor constitutes a second passageway. A third passageway connects the sump with one end of the hollow and a fourth passageway connects the other end of the hollow with the inlet passage. Fluid pressure in the outlet passage acts on the oil in the sump through the first passageway to force oil from the sump through the third, second and fourth passageways respectively to the inlet passage to lubricate the sliding contact portions of the rotor, shaft, vane and housing. Oil in the inlet passageway is sucked into the bore to lubricate the inner surface thereof and is discharged into the outlet passage from which it is returned to the sump through the first passageway. The third and fourth passageways may extend through chambers for bearings or mechanical seals for the shaft for lubrication thereof.