HOPPER

An improved hopper includes a pair of opposed live walls and a pair of opposed fixed walls, wherein at least one live wall is moveable relative to at least one other wall. The hopper is suitable for controlling the flow of particulate material of the type which has a tendency to bridge during transportation. A device for imparting vibration is coupled to at least one of the live walls. The live walls are separated from the fixed walls by seams such that the live walls are free to move relative to the fixed walls. By the action of the vibration device, the live walls are moveable relative to each other and to the fixed walls to inhibit the formation of particle bridges and, thus, provide a significant improvement in the capability of controlling the flow of particulate material. This relative wall motion is capable of breaking up bridges of the material that are otherwise likely to form, and of preventing the adhesion and packing of particulate material to or on the walls, thereby allowing the material to flow uniformly through the hopper.