Abstract: The present invention relates to a retaining device for retaining at least one external functional apparatus comprising at least two tube ports on a treatment apparatus, wherein the retaining device comprises at least two stops which restrict a rotational movement of the external functional apparatus inside the retaining device. It further relates to an external functional apparatus as well as a treatment apparatus.

Abstract: The present invention relates to an apparatus for treating a medical liquid which includes a treatment machine having a coupling surface, with a cassette made of a hard part having liquid-conducting passages which are covered by a flexible film being able to be coupled to the coupling surface of the treatment machine. The invention furthermore relates to a corresponding medical cassette. In accordance with the invention, an air-free coupling of the flexible film of the cassette to the treatment machine is ensured in that air can be sucked out areally along a plane between the flexible film and the coupling surface during the coupling process and/or with a coupled cassette. The invention equally includes a method for coupling the cassette and a method for checking the leaktightness of the cassette via the vacuum control of the air suction.

Abstract: The present invention relates to a pumping device for delivering and metering fluids, in particular medical fluids such as dialysis fluids, with a piston unit having a driving device and a piston and with a membrane unit which has a membrane and a first chamber bordered by the membrane. The pumping device also has a hydraulic unit which has a space to accommodate a hydraulic fluid which is connected to the piston of the piston unit and to the first chamber of the membrane unit. The reliability of metering by such a pumping device is increased by providing a control unit for guaranteeing a predefinable metering rate and/or quantity and also providing a measuring device by means of which the axial position of the piston unit can be determined directly and which can be connected to the control unit.