Patent ID: 6210138
Filing Date: 2001-04-03
Classification: F04C

Abstract:
Rotary pump apparatus comprising, in combination:a pump housing defining a housing interior, a fluid inlet opening in communication with said interior and a fluid outlet opening in communication with said interior and spaced from said fluid inlet opening;a drive gear having drive gear teeth rotatably mounted relative to said pump housing and located within said housing interior;a driven gear having driven gear teeth rotatably mounted relative to said pump housing and located within said housing interior, the drive gear teeth meshing with the driven gear teeth at a predetermined location and sequentially defining therewith during rotation of said drive gear and driven gear a plurality of spaces for transporting fluid from said fluid inlet opening to said fluid outlet opening, each space of said plurality of spaces located between said meshing drive gear teeth and said driven gear teeth increasing in volume during rotation of said drive and driven gears to decrease fluid pressure within said space prior to communication being established between said space and said fluid outlet opening; anda fluid-flow passageway at least partially defined by said housing connecting said inlet fluid opening and said space for introducing fluid into said space from said fluid inlet opening during increase in volume of said space during rotation of said drive and driven gears prior to communication being established between said space and said fluid outlet opening to relieve negative fluid pressure within said space during said increase in volume, said fluid-flow passageway extending between said predetermined location and said fluid inlet opening and being sequentially in communication with all the spaces defined by said drive gear and said driven gear at said predetermined location during rotation of said drive and driven gears.