The present invention concerns a device for injecting a liquid product contained in a bag, the device comprising a housing consisting of two half-shells articulated about an axis of rotation in order to allow the relative movement of the half-shells relative to each other between: —an open position in order to put the bag in place and—a closed position for injecting the liquid product contained in the bag, remarkable in that: —one of the half-shells comprises a deformable bladder—called the “active bladder”—having a volume that varies under the action of a hydraulic ram supplying said bladder with hydraulic fluid, and—the other of the half-shells comprises a deformable damping cushion having a constant volume—called the “passive cushion”.
