Piston pump and device for feeding and metering a fluid for medical purposes by means of a piston pump

Abstract

A piston pump is described for pumping a fluid, comprising at least two cylinders each having a piston which is movable inside the associated cylinder along the longitudinal axis of the cylinder by means of a drive, wherein cylinders are attached to a common pump flange. In each cylinder a chamber is formed having a volume that changes when the associated piston is moved in the cylinder. The pump flange extends along the direction of motion of the pistons, and at least one inlet port and one outlet port are attached to the pump flange, whose longitudinal axes run along the pump flange. A central valve plate is attached to the side of the pump flange facing away from the cylinders that bear on the pump flange and continuously rotates transversely to the pump flange during pumping operation of the piston pump. Respective passages are introduced to the pump flange in the region of each inlet and outlet port, and cylinder openings are introduced to the pump flange in the region of each cylinder. The valve plate has at least two cavities on the flange side, of which a first cavity coincides, upon rotation of the valve plate to a first angular position, with a cylinder opening of a first cylinder and a passage of the outlet port, while the second cavity coincides in this first angular position with the passage of the inlet port and a cylinder opening in the second cylinder. The first cavity then coincides, upon rotation of the valve plate to a second angular position, with the passage in the outlet port and a cylinder opening in the second cylinder, while the second cavity coincides in this second angular position with the passage in the inlet port and a cylinder opening in the first cylinder.