There are two basic types of rollers used in conveyors. One is the load-bearing roller, which supports the weight of the material placed on the conveyor and helps to move it. These have to be selected mainly according to the weight that is to be carried. The other type is the 'return' or 'lower' Conveyor Roller. Some of these have pointed rubber rings in the center and flat ones at the ends. The pointed rings break up the remains of carried material sticking to the belt. The flat rings protect the edges of the belt and facilitate its smooth return so that the loading can be continuous. They also prevent the belt from migrating beyond the tolerance limits. The return rollers can be equipped to clean themselves. The automatic cleaning of the conveyor belt and the rollers reduces the maintenance cost considerably. Conveyor Rollers are normally manufactured from mild steel, stainless steel, PVC or aluminum. There are different types to suit for specific uses. Food processing industry uses stainless steel or PVC rollers. There are specially designed rollers that can spray water to wash the material being carried. For conveyor bends, tapered rollers are used. Some manufacturers strive to reduce noise to the levels recommended by the Occupational Safety and Health Administration (OSHA) of the U.S. Department of Labor, by improving the design. Another variety used in conveyors is the impact roller. This is a support roller covered with shock absorbing rubber rings and is used mainly in systems moving heavy materials. It is fitted at the loading points to reduce the impact of the materials falling on to the conveyor belt. It may be motorized or gravity operated. The rollers move on bearings. Pre-lubricated bearings that are supplied by some manufacturers can minimize maintenance cost to a great extent. Also contributing to the operating cost reduction are high-tech internal motors to drive the rollers. |
