Abstract: A pressure regulation system for discharging a liquid having a predetermined liquid pressure from a liquid opening, including an elastic bag having a liquid phase and a gas phase, where the liquid opening in an operational position of the elastic bag is formed in the lower area of the elastic bag, at least two push elements, at least one drive unit and a control unit. The elastic bag has a gas opening, which extends into the gas phase. The pressure regulation system has a ventilation unit, which is connected to the control unit for communication and which connects to the gas opening of the elastic bag. The ventilation unit regulates the liquid pressure of the liquid discharged through the liquid opening by means of a gas supply into the elastic bag and/or a gas discharge from the elastic bag.

Abstract: A container for holding a liquid, in particular an infusion liquid or irrigating liquid, comprising a liquid phase containing the liquid and a gas phase, wherein, in the operating position, a liquid opening is formed in the lower region of the container and wherein the container has a gas opening. The gas opening is formed by a gas pipe which is inseparably connected to the container and has a first gas pipe end and a second gas pipe end. The first gas pipe end extends into the gas phase of the container and is provided with a closure. The second gas pipe end leads to the outside of the container.

Abstract: A system for measuring an amount of liquid in an elastic bag, where there is formed in the lower area of the elastic bag a liquid opening for retrieving liquid from the elastic bag. The system includes push elements, which abut at opposite walls of the elastic bag and which are spaced apart from one another, a drive unit, which is configured to drive at least one push element, sensors, and a control unit. The sensors are configured to measure a liquid level of the liquid in the elastic bag. The control unit is configured to calculate an amount of liquid in the elastic bag on the basis of the liquid level and the distance between the push elements. The liquid level of the liquid in the elastic bag is changeable by reducing the distance between the push elements by means of the at least one drive unit.