Abstract: A fluid tank comprises a rigid container and a bag to receive a fluid. The bag is arranged within the container and comprises a fluid opening to allow a fluid to flow therethrough. A perimeter of the bag extends in a first direction and in a second direction and is supported within the container, such that the perimeter of the bag is movable in no more than the first direction and the second direction.

Abstract: A known volume of liquid is delivered to a liquid supply system. A first pressure of the liquid supply system after delivery of a first known volume of liquid into the liquid supply system is determined. A second pressure of the liquid supply system after delivery of a second known volume of liquid into the liquid supply system is determined. The volume of compressible gas trapped in the liquid supply system is determined from the second known volume of delivered liquid and the first and second pressures.

Abstract: In an example, a valve for a printing fluid supply system is disclosed. In this example, the valve includes two rigid shells to provide connections to a first printing fluid supply cartridge, a second printing fluid supply cartridge and a printhead. Further, the valve includes a diaphragm with sealing elements disposed between the two rigid shells to selectively couple one of the first printing fluid supply cartridge and the second printing fluid supply cartridge to the printhead and seal other printing fluid supply cartridge using the sealing elements.

Abstract: There is provided a method, comprising configuring a liquid delivery means to deliver a known volume of liquid to a liquid supply system. A first pressure of the liquid supply system after the liquid delivery means has delivered a first known volume of liquid into the liquid supply system is determined. A second pressure of the liquid supply system after the liquid delivery means has delivered a second known volume of liquid into the liquid supply system in determined. The volume of compressible gas trapped in the liquid supply system is determined from the second known volume of delivered liquid and the first and second pressures.

Abstract: In an example, a valve for a printing fluid supply system is disclosed. In this example, the valve includes two rigid shells to provide connections to a first printing fluid supply cartridge, a second printing fluid supply cartridge and a printhead. Further, the valve includes a diaphragm with sealing elements disposed between the two rigid shells to selectively couple one of the first printing fluid supply cartridge and the second printing fluid supply cartridge to the printhead and seal other printing fluid supply cartridge using the sealing elements.