Within the bulk materials industries, belt conveyors are used extensively to feed materials via chutes to stockpiles, screen houses or crushers, and to transport stone around sites that often extend to several square kilometres. Materials may well travel along several conveyors to reach a destination, and on such large sites, conveyors naturally operate unattended. Chutes and transfer points through which the stone is discharged from one conveyor to another are potential weak points, and when such 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.
To avoid this a variety of techniques are employed to both warn of blockages and to automatically shut down conveyors and feeders before damage can be done. The most commonly employed technique is a flap switch, signalling from a proximity unit when the angle of the flap changes beyond certain levels. Because the flap is a mechanical, contacting, system, regular maintenance is required and the flap switches require periodic replacement. An alternative system makes use of microwaves fired across the chute. These are expensive, and careful positioning is required to ensure that the microwave path does not cross the normal flow of stone, or spurious alarms may be generated.
The Pulsar solution is to use non-contacting ultrasonic technology to measure “top-down” into the discharge of the conveyor. A robust dB3 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 and extremely reliable.
The blackbox 130 features two relays that can be configured to close or open at a user-programmed level, alerting staff or immediately switching the offending conveyor off before damage can be done. Pulsar’s blackbox family is designed as a component system, reducing cost by removing unnecessary elements of the system such as the unit display.
Blocked Chute Detection
May 31, 2005
Within the bulk materials industries, belt conveyors are used extensively to feed materials via chutes to stockpiles, screen houses or crushers, and to transport stone around sites that often extend to several square kilometres. Materials may well travel along several conveyors to reach a destination, and on such large sites, conveyors naturally operate unattended. Chutes and transfer points through which the stone is discharged from one conveyor to another are potential weak points, and when such 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.
To avoid this a variety of techniques are employed to both warn of blockages and to automatically shut down conveyors and feeders before damage can be done. The most commonly employed technique is a flap switch, signalling from a proximity unit when the angle of the flap changes beyond certain levels. Because the flap is a mechanical, contacting, system, regular maintenance is required and the flap switches require periodic replacement. An alternative system makes use of microwaves fired across the chute. These are expensive, and careful positioning is required to ensure that the microwave path does not cross the normal flow of stone, or spurious alarms may be generated.
The Pulsar solution is to use non-contacting ultrasonic technology to measure “top-down” into the discharge of the conveyor. A robust dB3 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 and extremely reliable.
The blackbox 130 features two relays that can be configured to close or open at a user-programmed level, alerting staff or immediately switching the offending conveyor off before damage can be done. Pulsar’s blackbox family is designed as a component system, reducing cost by removing unnecessary elements of the system such as the unit display.
For more information, please visit:
https://edir.bulk-online.com/oldedirredirect/201974.htm
Attachments
pulsar_process_news_31.5.05 (GIF)
■