Infusion system with a dosing device.

Infusion system with a dosing device for the infusion system with a dosing unit (2, 3) with a variable volume (6) in intermediate steps or gradually and with one connection for the supply and delivery (2a ) or connections that can be opened or closed alternately (2a, 2b), through which the variable volume (6) of the dosing unit (2, 3) can be filled with a substance and / or can be given a substance contained in the variable volume (6), wherein the dosing unit (2, 3) is a cylinder (2) with a piston (3) insertable into the cylinder (2) by a motor and an infusion, which can be connected, via or other motor, with the only supply connection and delivery (2a) by rotating the cylinder about its longitudinal axis, or with one of the connections that can be opened or closable in alternatingly (2a, 2b) by turning on the cylinder longitudinal, or by rotation or displacement of a seal member (7) with an opening (7a) arranged therein axis.