This is a conveying apparatus in which a load is moved by the force of gravity. These devices include trays (ramps, slide-ways) and gravity pipes. Conveyor must have an inclination angle which is determined by the relationship between the acceleration of movement of a load and the friction force.
Conveyors of this type are closed; there are no moving parts in them. Such conveyor system is simple, requires no maintenance, works silently and takes no energy.