Belt Conveyors Systems: Roller And Slider Bed Belt Conveyors

Belt conveyor consists of two or more pulleys with a continuous loop of material, known as the conveyor belt, rotating about them.  Primarily, one of the pulleys is powered, moving the belt and the material on the belt forward.  The powered pulley is referred to as the drive pulley, while the unpowered pulleys are called idle pulleys.  There are two main industrial classes of belt conveyors – those used for general material handling like moving cartons, totes and pallets, and those used for bulk material handling like transporting agricultural grains, coal and produce. Generally speaking, companies that specialize in general material handling belt conveyor, do not work with bulk material handling conveyors. 

Slider Bed Belt Conveyor

Belting consists of one or more layers of material.  Typically, the belts in general material handling have two layers – the “carcass”, which is the under layer of material that provides the belt’s linear stability, strength and shape, and the “cover” which is the over layer that provides the belt’s carrying or contact surface for the materials being handled.  The carcass is often comprised of cotton material or plastic web/mesh.  The cover is often various materials based on the belts intended use with the more common being rubber or plastic compounds.  Additionally, the belt is either laced and pinned together at the seam/splice or vulcanized (hot welded) to provide a seamless splice.

General material handling belt conveyor systems are typically comprised of one of two designs – roller bed belt conveyors, in which the belt is supported and carried by rollers, or slider bed belt conveyors, in which the belt is supported and carried over a continuous metal bed surface or a series of metal pans.  Roller bed design allows for longer runs of conveyor due to the lower coefficient of friction experienced between the weight of the product on the belt and the free-turning rollers (as compared to the drag created between the belt and the static bed surface and/or metal pans).

Roller Bed Belt Conveyors

Due to their versatility and affordability, belt conveyor systems are the most commonly used and applied powered conveyors. Product is carried directly on the belt surface, leaving all regular and irregular shaped, large and small, light and heavy items to be conveyed successfully. They are known for an ability to handle product with irregular bottom surfaces, small items that might otherwise fall between the rollers for conveyors of a different design, bags that might sag between the rollers for conveyors of a different design, and products with a “frame” type, minimum contact, bottom surface design.  Commonly, belt conveyors transport product in a straight line and/or through changes in elevation.  While they are used in some applicatoins for static accumulation of product, the implementation of controls logic allows them to be applied in dynamic, indexing accumulation applications as well.