Patent ID: 7134855

Claim:
A suction pump comprising: a drive housing having a front end; a shaft rotatably disposed in said drive housing, said shaft having a front face located adjacent the front end of said drive housing; a pump casing disposed over the front end of said drive housing, said pump casing defining a pump chamber that extends forward from the back face, the pump chamber having a diameter wherein, collectively the front end of said drive housing and said pump casing are shaped to define an inboard disc chamber that surrounds said pump chamber and has a diameter larger than the diameter of the pump chamber; a rotor integrally attached to the front face of said shaft to rotate with said shaft, said rotor positioned in said pump chamber, said rotor having a plurality of circumferentially spaced apart radially directed slots, and a diameter; a plurality of vanes disposed in said pump chamber, each said vane being disposed in a separate one of the slots formed in said rotor; and an inboard disc located between said shaft and said rotor so as to be located against the open end of said slots and secured to said shaft so as to rotate with said shaft and said rotor, said inboard disc having a diameter that is greater than the diameter of said rotor and being disposed in the inboard disc chamber, wherein, said disc is positioned to be spaced away from surfaces of said drive housing and said pump casing that define the inboard disc chamber.