Patent ID: 6030191
Filing Date: 2000-02-29
Classification: F04C

Abstract:
A suction pump, said suction pump having:a pump casing, said pump casing having a pump chamber, an inlet port into said pump chamber and an outlet port from said pump chamber, wherein said inlet port and said outlet port are spaced apart from each other;a rotor disposed for rotation in said pump chamber, wherein said rotor is positioned to define in said pump chamber a fluid transport section that is located between said inlet port and said outlet port; anda plurality of spaced apart vanes mounted to said rotor so as to extend from said rotor, wherein each adjacent pair of vanes defines a fluid cavity within said pump chamber and said vanes are arranged so that, during rotation of the rotor, a plurality of said fluid cavities are periodically completely positioned in the fluid transport section of said pump chamber; andwherein said pump casing is further formed to define a bleed duct that extends from said outlet port towards said fluid transport section of said pump chamber and a plurality of bleed ports are formed in said pump casing that provide fluid communication between the bleed duct and the fluid transport section wherein the bleed ports are positioned so that at least a first bleed port opens into a portion of the fluid transport section subtended by a first one of the fluid cavities and at least a second bleed port opens into a portion of the fluid transport section subtended by a second one of the fluid cavities.