Abstract: A bag-in-box container is provided with a spout at an upper opening and a pressurizing element applying pressure to a flexible container. The pressurizing element includes two plate devices being urged apart by a resilient element. The two plate devices are provided with engageable hook elements that may be set out of engagement by shifting one of the plate devices with respect to the other along the plane of the plate devices; the shift causing all hooks to disengage simultaneously. This shifting apart action is performed from the side of the pressurizing element, facilitating disengagement from the side of the bag-in-box container. In one embodiment, a disengagement port is provided giving access to the pressurizing element, such that the at least two plate devices may be brought out of engagement with each other. The disengagement port may be a second opening on the side of the rigid casing.