Patent ID: 7217083
Filing Date: 2007-05-15
Classification: F04D

Abstract:
1. A regenerative pump comprising: a casing that forms a generally annular fluid passage, which conducts a fluid; and an impeller that is rotatably received in the casing and has a plurality of blades, which are arranged one after another in a circumferential direction to provide kinetic energy to the fluid in the fluid passage upon rotation of the impeller, wherein the regenerative pump satisfies a relationship of 0.60≦b/a≦0.76, where “a” is an axial width of each blade, and “b” is a total axial distance, which is a sum of a first axial distance between a first axial side outer edge of the blade and an opposed first axial side inner wall of the fluid passage and a second axial distance between a second axial side outer edge of the blade and an opposed second axial side inner wall of the fluid passage; and the regenerative pump satisfies a relationship of 1.0≦S2/S1≦1.2 where “S1” is a size of a blade passing zone cross sectional area of the fluid passage, which is perpendicular to a flow direction of a mainstream of the fluid in the fluid passage and through which the blades pass, and “S2” is a size of a blade non-passing zone cross sectional area of the fluid passage, which is perpendicular to the flow direction of the mainstream of the fluid in the fluid passage and through which the blades do not pass, the impeller further including a plurality of impeller main body portions each of which is joined to a radially inner end of a corresponding one of the plurality of blades and extends between circumferentially adjacent blades, a surface of an axially inner end of a radially inner end side curve wall of the fluid passage and a surface of an adjacent axially outer end of each of the plurality of impeller main body portions extend along an imaginary common curve in such a manner that an imaginary tangential line X which contacts the imaginary curve at an intermediate point between the surface of the axially inner end of the radially inner end side curved wall of the fluid passage and the surface of the adjacent axially outer end of each of the plurality of impeller main body portions extends parallel to a rotational axis of the impeller.