Conveyors auxiliary equipment

Auxiliary Equipment Elevating conveyors must be equipped with some form of holdback or brake to prevent reversal of travel and subsequent jamming when power is unexpectedly cut off. Ratchet and wedge roUer-type holdbacks are commonly used. Solenoid brakes and spring clutches may also be employed. 

Conveying-screen dryers are fabricated with conveyor widths from 0.3- to 4.4-m sections 1.6 to 2.5 m long. Each section consists of a sheet-metal enclosure, insulated sidewalls and roof, heating coils, a circulating fan, inlet air distributor baffles, a fines catch pan under the conveyor, and a conveyor screen (Fig. 12-51). Table 12-23 gives approximate purchase costs for equipment with type 304 staimess-steel hinged conveyor screens and includes steam-coil heaters, fans, motors, and a variable-speed conveyor drive. Cabinet and auxiliary equipment fabrication is of aluminized steel or stainless-steel materials. Prices do not include temperature controllers, motor starters, preform equipment, or auxiliary feed and discharge conveyors. These may add 75,000 to 160,000 to the dryer purchase cost (2005 costs). 

Auxiliary equipment in a wider sense comprises hammer drills — hydraulically powered, as a rule - which are installed on telescopic mountings near the feed hopper and apron conveyor and can be used to break up any oversize pieces of rock that get into the hopper. The same method is used also for dealing with such pieces that inadvertently reach the hoppers on jaw crushers or gyratory crushers. 

Conveyor-Befc Devices The metal-belt type (Fig. 11-55) is the only device in this classification of material-handling equipment that has had serious effort ejq)ended on it to adapt it to indirect heat-transfer service with divided solids. It features a lightweight construction of a large area with a thin metal wall. Indirect-cooling applications have been made with poor thermal performance, as could be expected with a static layer. Auxiliary plowlike mixing devices, which are considered an absolute necessity to secure any worthwhile results for this service, restrict applications. 

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