MATERIALS HANDLING


Cradles offer low friction surfaces at specified trough angles for superior belt sealing


THE POWER TRADE-OFF


Andrew Timmerman advises on accurately calculating conveyor belt sag between idlers to minimise spillage and dust at transfer points


S


pillage in the loading zone of a belt conveyor can raise the cost of operation significantly both from an efficiency and


safety standpoint. One of the main sources of spillage stems from the weight of the cargo causing the belt to sag creating gaps in-between idlers. Aided by air pressure in the transfer chute, dust and fines escape, resulting in fouled idler bearings and mechanical parts, causing them to fail


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and be replaced. The spillage piles below the system


and clutters walkways requiring additional workers to clean it up, raising the cost of labour and causing a possible workplace hazard. If not regularly addressed, the spilled material can encapsulate the belt and tail pulley, fouling the unprotected return side of the belt. By far the most expensive single component on any conveyor system, a belt with material


adhered to the underside leads to abrasion damage, mistracking and slippage which increases the power requirements. To avoid these consequences and


mitigate belt sag, conveyor designers recommend constructing a sealed environment in the transfer chute: reducing the distance between idlers or adding cradles. Cradles are slick urethane pads on a rigid steel frame that produce an even belt path


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