Belt conveyors are usually built with two or more pulleys, with a constant movement of the conveyor belt rotating to move product. One or both of the pulleys are powered, moving both the belt and the product on the belt onward.
Belt conveyors can come with flat bed or on rollers. Each fills specific needs. Belt is almost always used to take product from one floor level to the next, either up or down. With lighter product, a limited use of rollers can also provide a quieter system.