Patent ID: 8590739

Claim:
A method for operating a pneumatic device for metering the delivery of portions of a liquid from a liquid container containing the liquid, the method comprising: setting a pressure in a pressure tank to an initial pressure level that is greater than a pressure level p B1 to be achieved in the liquid container during delivery of a portion of liquid, and performing repeatedly the following steps for delivering one portion of liquid after the other: delivering a portion of liquid by temporarily coupling the liquid container to the pressure tank in order to apply a pressure pulse to the liquid container, and after the liquid container has been decoupled from the pressure tank, increasing the pressure in the pressure tank to a pressure level p T2 that is greater than the pressure level p B1 , wherein the pressure tank is couplable to a compressed air source by means of an inlet valve and to the surroundings by means of an outlet valve, wherein the inlet valve keeps the coupling between the pressure tank and the compressed air source interrupted and the outlet valve keeps the coupling between the pressure tank and the surroundings interrupted while the pressure tank is coupled to the liquid container.