Patent ID: 8147225

Claim:
A pump comprising a) a housing; b) a working chamber located in the housing for delivery of a fluid; c) a suction channel which is in flow connection with the working chamber for guiding the fluid into the working chamber; d) a valve unit disposed in the suction channel, the valve unit comprising i) a guide body; ii) a valve which is movable between an open position and a sealing position for controlling the flow of the fluid in the suction channel, the valve being guided for displacement; and wherein the valve comprises a valve disk and a valve stem connected thereto; iii) a limiting element which is guided for displacement in the guide body and comprises at least one displacement stop for limitation of displacement; wherein the displacement stop arranged such that in the sealing position of the valve, the valve disk is lifted off the limiting element; and iv) a pressure element which presses the limiting element in a direction towards the sealing position of the valve; and e) a pressure channel which is in flow connection with the working chamber for guiding the fluid out of the working chamber.