Rotary vane compressor with relief means for vane slots

Claim 1

A rotary sliding vane compressor comprising: a housing providing a gas working chamber having a cylindrical wall and including end plates closing said chamber; a cylindrical rotor mounted for rotation in said chamber and having opposed end surfaces and a plurality of inwardly extending vane slots formed therein; said rotor being in sliding contact with said cylinder wall at a contact point; a gas inlet port communicating with said chamber; a gas discharge port adjacent said contact point communicating with said chamber; a gas discharge chamber associated with said housing, said gas discharge chamber having a sump portion for the accumulation of lubricating fluid separated from said gas; a plurality of vanes slidable in said vane slots each having one end thereof flush with one of the end surfaces of said rotor, a vane tip in contact with said cylindrical wall and a lower edge defining, in cooperation with the bottom of said vane slots and at least one of said end plates, an undervane space; means defining a first fluid passage in said one end plate having a fluid supply port at one end of said passage and an inlet at the opposite end, said supply port being located so that it communicates with an undervane space as the rotor moves in a direction from said gas inlet port to said gas discharge port, said fluid supply port being out of communication with said undervane space for a predetermined distance before said vane tip reaches said contact point; means for supplying a substantially incompressible fluid to said inlet whereby said fluid flows through said passage and fills said undervane spaces, trapping a predetermined quantity of fluid in said undervane spaces; said fluid being confined, except for high flow resistance leakage paths between said rotor and said housing, and between said vanes and said vane slots, as said vane approaches said contact point, said last-named means including a conduit through which said fluid is transferred from said sump portion, having an outlet aligned with, but spaced from, said fluid supply passage inlet and a disc-like element interposed between said conduit outlet and said fluid supply passage inlet and driven with said rotor, said element having a plurality of apertures therein adapted to intermittently and periodically interconnect said conduit to said fluid supply passage and means defining a second fluid passage in one of said end plates, said passage having a first portion adapted to communicate with said undervane spaces, said second fluid passage having a portion which extends into said gas working chamber so as to relieve suction created by the vanes moving outwardly during the suction phase.