Patent ID: 6116850
Filing Date: 2000-09-12
Classification: F04D

Abstract:
A pump comprising: a pump housing comprising a walled internal pumping channel extending arcuately about a main axis; a fluid inlet to, and a fluid outlet from, the pumping channel spaced arcuately apart about the axis; and a pumping element that is disposed within the housing for rotation about the axis and has a vaned periphery that is operable within the pumping channel for pumping fluid from the inlet to the outlet when the pumping element is rotated; the channel having an upstream portion that extends from the inlet and is followed by a downstream portion extending to the outlet; the upstream portion having a larger cross sectional area than the downstream portion; a vent hole for venting liquid-entrained vapor from the channel while the pumping element is being rotated to pump fluid from the inlet to the outlet; the vent hole extending from the surface of a wall that forms one axial boundary of the channel, through that wall, and out of the housing; the vent hole having an entrance that intersects the surface of the wall at the downstream portion of the channel beyond a ramp in the surface of the wall that demarcates the downstream portion of the channel from the upstream portion of the channel; the pumping element having a surface that confronts the surface of the wall as the pumping element rotates; a zone of that pumping element surface being spaced axially from the entrance of the vent hole a distance Z; the ramp having a beginning that is spaced from a center of the vent hole a distance L; and the ratio of Z to L being no greater than 1.5.