Abstract: A diaphragm pump comprises a carrier part, a drive motor with a drive shaft, a pump head with a pump chamber delimited by a diaphragm, and an inlet port and outlet port. The pump head is connected to the drive shaft such that the direction of oscillation of the diaphragm is orthogonal with respect to the axis of rotation of the drive shaft. A drive transmission element is mounted on the pump head and is guided in a bearing disk mounted to be rotatable eccentrically, so as to be displaceable orthogonally with respect to the direction of oscillation of the diaphragm, such that the drive transmission element generates the oscillatory movement of the diaphragm in the pump chamber during the rotation of the pump head, and as a result of the rotation a pump medium line arranged therein is alternately connected to the inlet port and the outlet port.

Abstract: A positive displacement pump (1) for transporting a fluid with automatic adaptation to the compressibility of that fluid has a pumping chamber (15) with a variable volume (V) which is on the one hand delimited by a rigid chamber cover plate (10) and on the other hand by an elastic diaphragm (9), a suction channel (29) which is in flow connection with the pumping chamber (15) for sucking the fluid to be transported into the pumping chamber (15), an outlet channel (24) which is in flow connection with the pumping chamber (15) for discharging the fluid to be transported from the pumping chamber (15), and a drive device (29) for cyclically increasing and reducing the current volume (V) of the pumping chamber (15), with the drive device (29) being connected to the diaphragm (9) by means of a diaphragm connecting element (34; 34a; 34b) which is spring-mounted in the drive device (29) by means of a spring element (33; 33a; 33b).