Conveyors come in many shapes and sizes. Used on a host of jobsites, in production plants, or at material-recovery facilities, conveyors move materials from one portion of the facility to another. Conveyors are found in areas like municipal solid waste sites, food-processing facilities, in the paper industry, pharmaceutical companies, or in mining operations.
Conveyors are used to transfer materials from one location to another—often in difficult situations, such as a steep incline or on a difficult jobsite. They can generally be split into two categories, screw conveyors and belt conveyors, but there are many other types and offshoots of the two basic concepts.
Greek mathematician and physicist Archimedes is acknowledged as the inventor of the screw conveyor in 235 to 240 B.C., and essentially his design has not changed since then. Screw conveyors are used where a fully contained, metered environment is needed. Materials like sludge and powders might be moved using these systems. These vertical or horizontal conveyors may use stainless steel, carbon steel, galvanized metal, ribbon flighting, tapered screws, hard facing, in-feed hoppers, or a discharge chute. Screw conveyors are less common for moving solid waste—they're more commonly used for dust-free movement of grains, flakes, or granules.
Belt conveyors are one of the most forgiving types of designs and are widely used due to the open frame and troughing effect of the belt, which fully contains the load of the materials. These are commonly used in the aggregate and mining industries, since they can handle exceptionally high loads over long distances. Conveyor belts are loops that traverse between two or more pulleys, and are supported by idler rolls at intermediate points. Materials from fine powders to large, lumpy garbage can be handled on a conveyor-belt system.
A belt conveyor may move municipal solid waste, commercial waste, paper, plastic, aluminum, or ferrous cans. Construction of these belts is rugged, since the environment is very abusive in transfer stations and municipal solid waste baling operations or recycling plants.
Belt construction and materials are often application specific. Belt materials and configuration vary for such specific uses as solid waste conveying, moving recycled materials, and a wide variety of others. Belt dimensions are frequently customizable to match the user's specifications or application needs. These belts may be made of nonabsorbent material and provide easy cleanability.
Conveyor-belt manufacturers design many styles of convey or belts including flat belts, v-belts, magnetic belts, trough belts, and rubber conveyor belts. Primary conveyor-belt materials include aramid, cotton, canvas, ethylene-propylene-dienemonomer, leather, neoprene, nitrile, nylon, polyester, polyurethane and urethane, polyvinyl chloride, rubber, silicone, and steel (including stainless steel and steel cord).
Conveyors are not solely used for solid waste, however. The more “fluid” wastes that these conveyors can move include water and sludge.
The Conveyor Equipment Manufacturers Association (CEMA, www.cemanet.org) can provide a municipality with a great deal of information about conveyor standards, manufacturers, safety information, and technical publications. CEMA's publications offer a solid waste facility manager basic handbooks, installation methods, and safety videos for the facility's staff.
Conveyor equipment providers
A selection of companies who provide equipment for the waste industry