PRESSURE-COMPENSATING DEVICE FOR A DUAL CONTAINER

摘要

Dual containers, consisting of an inner container (2) and a diffusion-tight outer container (1) are used for medical fluids. The inner container collaps es when the fluid is removed. A pressure-compensating device is required to compensate the pressure between the gas chamber (15) that is located between the inner and outer container and the surrounding area of the dual container , whereby the loss of fluid is kept to a minimum by diffusion from the collapsible inner container. At least one duct (7) that links the gas-filled space to the surrounding area of the dual container is used for this purpose . The time constant for compensation of a pressure differential of several millibars is several hours. This is achieved by selecting the length of the duct and cross section thereof. The at least one duct can be produced individually or a plurality of ducts can be provided in the form of pores in an open-pored sintered material or a permeable membrane. The pressure- compensating device enables the dual container to be stored for years and, i f the fluid is removed in portions in a correct manner, it can be used for several weeks. During these periods, the amount of liquid in the inner container or the concentration thereof varies substantially less than if a dual container known per se is used.