Just the job for Dust suppression

• 
• 30th September 2008
• Quarrying
 

 

Pulsar Process Measurement has supplied non-contacting ultrasonic equipment to initiate and switch off dust suppression systems for Lafarge Aggregates in Leicestershire, at a rail loading station and at a key conveyor transfer point. The application is important as dust is a significant potential nuisance, and both the open topped rail trucks and the long conveyors pass close to residential areas.

It is important to optimise the usage of the dust suppression chemicals, which makes it crucial to reliably detect the stone so that it can be fully coated without either missing any of the aggregate or overspraying either between the rail cars or on the conveyor when no stone is running.

A variety of methods had been tried before the ultrasonic equipment was used, ranging from load sensors on the conveyor to optical systems on the rail cars. None had proved reliable or accurate enough.

On the rail cars, Pulsar supplied a blackbox control unit with a dB10 transducer providing a measurement range of up to 10 m. As the stone is fed into the rail truck the ultrasonic unit is set to provide a relay signal once the car has reached the ‘full' level. This initiates the spray system and the stone is doused with the dust suppressant. The ultrasonic unit will not allow the stone to be sprayed until it sees a full level, and it also switches off the spray between rail trucks.

The conveyor application is slightly different. The ‘span', ie, the difference between the measurement with no stone present and with stone on the conveyor is of the order of 50-100 mm, so a dB3 transducer with a 3 m range has been fitted above the conveyor and controls a spraybar that coats the stone on the conveyor. The suppressant is metered onto the stone as it passes along the conveyor, keeping the environment clean and helping to maintain good relations between the quarry and its neighbours.

Pulsar Process Measurement Ltd

Cardinal Building EnigmaCommercial Centre
Sandy's Road
Malvern
Worcestershire
WR14 1JJ
UK

T: 0870 6039 112
F: 0870 6039 114