Method for dispensing a fluid medium

Abstract

The invention relates to a method for metering a fluid medium by means of a metering device in the form of a piston pump having a cylinder (Z) and a movable piston (3), wherein the cylinder (Z) and the piston (3) form a working space (A), characterized in that in a first method step a given filling quantity of the fluid medium is conveyed into the working space (A), wherein the filling quantity is greater than the predefined quantity to be metered, and in that in a further method step the piston (3) reduces the size of the working space (A) to such an extent that the quantity to be metered remains in the working space (A), wherein at the same time a valve (18, 18′) is opened so that the gas volume separated in the working space (A) and/or the excess fluid medium can flow out of the working space (A) through the piston, wherein to this end the piston (3) has at least one axially running through-channel (17, 17′) which is connected to a return line (19, 19′), and at least the controllable valve (18, 18′) and/or a non-return valve is arranged in the through-channel (17, 17′) and/or the return line (19, 19′).

Dependencies are inferred from the claim text.