| 摘要 |
Vane type rotary pumping device comprising a stationary housing member having a cavity extending therethrough, a rotor disposed in the cavity for rotation therein and having a plurality of radial openings therein, and vane members extending in each of the openings for sliding movement therein and rotary movement along with the rotor. An inlet passage and an outlet passage formed on spaced apart portions of the housing member communicate with the cavity. The cavity includes a first cylindrical channel extending from the inlet passage to the outlet passage to serve as a fluid pumping chamber. The vane members extend radially outwardly of the rotor and in substantial pressure sealing relationship with the channel but maintaining a slight clearance therebetween while being rotated through the channel by the rotor to pump fluid from the inlet passage to the outlet passage. The cavity also includes a second cylindrical portion between the outlet passage and the inlet passage over which the rotor passes with the vane members retracted within the rotor. A circumferential groove extending in the second cylindrical portion provides communication between radial openings simultaneously passing the second cylindrical portion to relieve pressure therein and to thereby facilitate radial movement of the vane members.
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