A container assembly with valve (10) comprising: a container (12) for storing a fluid container extending in an axial direction and having an open front end (12a)； a valve (14； 14 ') disposed in the container, the container valve assembly is configured so that axial movement is prevented forward of the valve relative to the container； and the piston element (32) disposed axially downstream of the valve, the piston element movable axially in the container and defining a first volume (24) in the container between the plunger member and valve, where the plunger member it is configured to increase the fluid pressure in the first volume upon movement axially forward relative to the valve； wherein the valve comprises: a permanent seal (16) sealing hermetically the valve into the container around the perimeter of the valve； and a channel (18) passing the permanent seal, the channel has a first opening (20a) in continuous communication with the atmosphere outside the assembly container valve and a second opening (20b) sealed selectively the first volume by flexible seal (22； 22 ')； wherein the flexible seal is movable between a sealing configuration and an open configuration to seal selectively the channel of the first volume, wherein in the sealing configuration the flexible seal seals hermetically the valve to the container to fluidly isolate said second channel opening of the first volume, and in the open configuration the second channel opening is in continuous communication with the first volume； and wherein the flexible seal is movable from the sealing configuration to the open configuration when the fluid pressure in the first volume exceeds a first threshold pressure.Un ensamble de contenedor con válvula (10) comprende: un contenedor (12) para almacenar un fluido, el contenedor que se extiende en una dirección axial y que tiene un extremo delantero abierto (12a)； una válvula (14； 14') dispuesta en el contenedor, el ensamble de contenedor con válvula se configura de
