On large sites, materials such as stone or coal may well travel along several conveyors to reach a destination, and usually operate unattended. Chutes and transfer points through which the stone is discharged from one conveyor to another are potential weak points, and when large quantities of heavy material are concerned a blocked chute can very quickly cause significant damage to conveyors, creating hours of downtime, thousands of pounds worth of expense and lost production.
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The most common warning system is a flap switch, but because the flap is a mechanical, contacting, system, regular maintenance is required and the flap switches require periodic replacement. Microwave alternatives are expensive and fiddly to install correctly.
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The Pulsar solution is to use non-contacting ultrasonic technology to measure “top-down” into the discharge of the conveyor. A robust transducer fires an ultrasound pulse into the chute and receives the echo from the stone while the associated blackbox 130 transceiver, which may be up to 1000m from the transducer, analyses the signal received, calculating the materials distance from the transducer. The system is maintenance-free, highly cost-effective and extremely reliable.
The blackbox 130 features two relays that can be configured to trigger alarms to alert staff or immediately switching the offending conveyor off before damage can be done.
Following trials, Aggregate Industries has purchased a number of units for their Croft quarry. Another Leicestershire quarry, Midland Quarry Productss Cliffe Hill site, has installed four systems for use with new conveyors.
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