Patent ID: 7335003

Claim:
A pump comprising: a housing having an internal chamber disposed therein extending from a first housing end to a second housing end; a pressurizing assembly axially movably disposed within the chamber comprising: a pressurizing member having an imperforate head positioned adjacent the housing first end and a thin-walled skirt extending circumferentially around and defining an edge of the head, the skirt having a desired axial length and having a flange positioned around a peripheral edge of the skirt, the pressurizing member having a backside surface including an opening disposed partially therein; a support coupled to the pressurizing member backside surface and having a cylindrical outside surface that is sized to accept placement of the skirt thereon; a shaft projecting through the support and into the pressurizing member opening, the shaft being coupled to the pressurizing assembly; a fluid transport body attached to the housing first end and comprising a fluid chamber therein that includes a fluid inlet port and a fluid outlet port, wherein the pressurizing member flange is interposed between the body and the housing; an actuator housing attached to the housing second end and comprising an actuator disposed therein for moving the shaft to cause axial movement of the pressurizing assembly within the housing chamber; means connected to the housing for maintaining a desired positive pressure differential within the pump between the fluid chamber and housing chamber to provide a desired pressure force on the skirt to bias it into contact against a supportive surface of the housing chamber or support during pressurizing assembly axial movement; and check valve means in fluid flow communication with the fluid inlet and fluid outlet ports to ensure checked one-way passage of fluid into and out of the fluid chamber during respective intake and output strokes of the pressurizing assembly; wherein axial movement of the pressurizing assembly is facilitated by rolling movement of the pressurizing member skirt between adjacent concentrically positioned surfaces of the housing chamber and the support.