The hopper is a welded or prefabricated structure and is suitable for short-term storage of grain products or compound feed, dust, cement, mineral fertilizers, etc. Usually, the structure of the bunker is a square pyramid with a narrow part to the ground, or a rectangular or specific shape. The angle of inclination of the side walls of the hopper depends on the product and ranges from 40 to 75 degrees. The thickness of the metal of the walls of the hopper is from 2 to 12 mm and depends on the dimensions of the hopper itself and the product. It is possible to line the walls with polyethylene or polyurethane. Support structures are usually made of pipe and they can be adjusted to the bunker during installation. For the maintenance of bunkers, if desired, the following is provided: special viewing hatches for control and observation; stairs with a fence for access to the roof; service sites for sampling; additional elements that provide ease of maintenance and control of bunkers.