A hopper is a device that temporarily stores coal, ore, gravel, sediment, screen residue, dewatered cake, etc., and then transports the required amount to a transportation means.
Generally, a hopper is a square box-like structure with a narrowed bottom like a funnel, and a gate attached to it opens and closes.
It is designed to drop the required amount.
The gate opens when Power Cylinder attached to it moves backward, and closes when it moves forward.
These devices are often installed outdoors and require a pressure stop on the cylinder to prevent the contents from falling out when closed.