Abstract: A hydraulically driven membrane pump for conveying a fluid, including a pumping chamber, a working chamber and a membrane which separates the pumping chamber and the working chamber in a fluid-tight manner, and means for reciprocating the membrane between a suction stroke position and a pressure stroke position, wherein the pumping chamber comprises at least one suction port through which the fluid to be conveyed is sucked into the pumping chamber in the suction stroke, and at least one discharge port through which the fluid to be conveyed is discharged from the pumping chamber in the pressure stroke, the membrane being connected on the working chamber side to a pull rod which is resiliently biased in the direction of the movement of the suction stroke.

Abstract: A metering diaphragm pump includes a metering chamber, a working chamber and a metering membrane. The metering chamber and the working chamber are separated from one another by the metering membrane. A device for moving the metering membrane back and forth between a first and a second position is provided. The volume of the metering chamber is smaller in a first position than in the second position, and a protective membrane is disposed next to the metering membrane on the working chamber side.

Abstract: The present invention concerns a hydraulic element comprising a sleeve-shaped casing and a piston reciprocable in a longitudinal direction in the sleeve-shaped casing. To provide a hydraulic element for use in displacement pumps for conveying small amounts of liquid, in which the danger of breakage or deflection of the hydraulic element is reduced, it is proposed according to the invention that the piston has a cavity extending in the longitudinal direction and having a cavity entry, wherein there is provided a pin which extends through the cavity entry into the cavity and which is connected to the sleeve-shaped casing at the sleeve-shaped casing or by way of an intermediate element so that in a reciprocating movement of the piston a relative movement occurs between the piston and the pin. The present invention further concerns a displacement pump having the hydraulic element according to the invention.

Abstract: The invention relates to a device for generating a pulsating hydraulic fluid pressure in a working chamber (1) filled with hydraulic fluid, comprising a driveable working piston (4) movably guided in a hollow working cylinder, wherein a working chamber (1) that is in fluid communication with the working piston (4) is provided, such that, by means of the movement of the working piston (4) within the hollow working cylinder, a pulsating hydraulic fluid pressure can be generated in the working chamber (1).

Abstract: The invention relates to a device for generating a pulsating hydraulic fluid pressure in a working chamber (1) filled with hydraulic fluid, comprising a driveable working piston (4) movably guided in a hollow working cylinder, wherein a working chamber (1) that is in fluid communication with the working piston (4) is provided, such that, by means of the movement of the working piston (4) within the hollow working cylinder, a pulsating hydraulic fluid pressure can be generated in the working chamber (1).