Belt conveyors idler

Comparative costs for conveyor systems can be based only on studies of specific problems. For example, belt-conveyor idlers are available in a range of quahties that may make the best unit cost three times as much as the cheapest. Bearing quahty, steel thickness, and diameter of rolls all affect cost, as does design for easy maintenance and repair. Therefore, it is necessary to make cost comparisons on the basis of a specific study for each conveyor application. 

Fig. 1.—Standard three pulley belt-conveyor idlers.

Hou Hui Wang Yun. Factors Affecting the Service Life of Belt Conveyor Idlers. Journal of Jiangsu Vocational and Technical Institute of Economics and Commerce, 2 61-63 (in Chinese). 

Huang Yuzhi 2000. Belt Conveyor Idler Performance Evaluation and Selection. Coal Scieru e and Technology. 4 13-16 (in Chinese). 

Miao Cai 2012. Belt conveyor idler process design and improvement. Hoisting and Conveying Machinery. 12 99-101 (in Chinese). 

Belt Conveyors. A belt conveyor is made up of an endless fabric or elastomer covered belt that traverses between two or more pulleys, and is supported at intermediate points by idler roUs. These conveyors can handle a wide range of materials, from fine powders to large, lumpy stone and coal. Material can be transported at rates of over 5000 t/h and the conveyors operated at belt speeds ranging from 20 to 300 m /min over very long distances. VersatiHty, reHabiHty, and range of capacities have made belt conveyors the most commonly used bulk handling conveyors in industry. 

Fig. 1. (a) Belt conveyor and support assembly, (b) 20° troughing idler, and (c) return idler. 

Take-Ups. A take-up is requited on a belt conveyor to ensure the proper belt tension at the drive pulley and along the conveyor, as weU as to ensure the proper troughing contour between idlers. A take-up is also needed to compensate for changes in belt length caused by elastic stretch during start-up, and any elongation characteristics of the belt that occur over a period of time. 

When samphng from moving belt conveyors, the cutter operates in a radial mode with the belt surrace contoured at the point of samphng by idlers, fixing radial curvature to the outer radius of the cutter. Clearance is minimized between outer edges of cutter blades and belt surface by cutter-shaft adjustment in the drive-clamping bracket. 

TABLE 21-7 Belt-Conveyor Data for Troughed Antifriction Idlers ... 

FIG. 21-4 Belt -conveyor loading details, (a) Typical sldrt-plate design and dimensions, (h) Pad belt and special roller-bearing idlers for heavy-duty loading Stephens-Adamson Division, Mlis-Chalmers Corporation.)... 

Belt conveyors are the most commonly used type of equipment for the continuous transport of solids. They can carry a wide range of materials economically over long and short distances both horizontally or at an appreciable angle, depending on the angle of repose of the solids. A belt conveyor consists of an endless belt of a flexible material, supported on rollers (idlers), and passing over larger rollers at each end, one of which is... 

Figure 5.9. Some arrangements of belt conveyors (Stephens-Adamson Co.) and types of idlers (FMC Corp.). (a) Horizontal conveyor with discharge at an intermediate point as well as at the end. (b) Inclined conveyor, satisfactory up to 20° with some materials, (c) Inclined or retarding conveyor for lowering materials gently down slopes, (d) A flat belt idler, rubber cushion type, (e) Troughed belt idler for high loadings usually available in 20°, 35°, and 45° side inclinations.

A belt conveyor essentially consists of an endless belt supported and stretched by pulley assemblies at each end and conveyor idlers along the profile on both carrying and return runs. One of the pulleys is the head and drive pulley, while the other is the tail pulley. For horizontal or slightly inclined installations, the idlers are placed either horizontally or, most commonly, V- or troughlike, to increase the capacity of the belt conveyor and to reduce material spillage. Also, the idlers at the carrying run are placed in shorter distances than the return idlers, in order to support the load-carrying belt. The belt is made of rubber or, in most cases, by synthetic material. In heavy-duty works, the belt is reinforced with two to four cotton or nylon layers. 

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