Solving the problems of dust emissions and material spillage in cement production
Teams from BLT WORLD and ScrapeTec work closely with customers in many industries to solve the problems of dust emissions, material spillage and conveyor belt damage that can lead to production downtime, costly repairs and even dangerous accidents.
In a recent project, a cement production plant needed assistance with excessive dust emissions during the handling of clinker, sand and gravel, that were causing Occupational Health and Safety (OHS) issues. In addition, the operator faced the problems of costly material spillage and the need for ongoing conveyor belt repairs.
A comprehensive site inspection revealed that a standard chute sealing system was used in conjunction with a basic clamping system positioned outside the chute. The existing skirting system and lack of inner skirting failed to contain excessive dust emission and material spillage at the transfer points. High dust levels resulted in poor visibility of the 70-metre-long conveyor tunnel, which negatively affected the maintenance team’s ability to monitor efficiencies during the ship unloading process and to prevent bottlenecks in the production process.
“Apart from concerns about safety and environmental hazards, management needed to find an urgent solution to eliminating the need for additional cleaning of the spillage piles. Dust extraction trucks were a costly necessity to clean the walkway and tunnel on regular base to prevent tripping and slipping.
“ScrapeTec initially installed the contact-free AirScrape® conveyor belt skirting system in the ship’s unloading transfer chute in 2020 on a trial basis. The operator was satisfied with the outcomes achieved at this transfer point and welcomed the implementation of additional systems to further improve efficiencies at the plant,” explains “Ken Mouritzen, Managing Director, BLT World. “This entailed a few necessary adjustments before the AirScrape, TailScrape and the ceramic ST-Containment seal and ST-Sure belt support system was installed and fully operational within the chute area.
“After the second phase installation, the operator records problem-free transfer points and a reduction of approximately 98% of dust emissions and material spillage. His onsite team reports no belt damage since the new equipment was installation and no maintenance or cleaning services have been necessary. Maintenance teams are relieved that with dust and spillage now under control, visibility of the tail end of the 70-metre-long conveyor from the head chute is vastly improved.”
The plant operator plans to upgrade all the chutes in the conveyor stream, from ship unloading to the stockpiles, which represents five transfer points. The core business focuses on unloading cement materials utilised for cement production. Finished cement products are then packed into 20 kg bags and bulk raw materials are loaded into trucks to service building, construction and road development projects.
Additional information
AirScrape
The contact-free AirScrape conveyor belt skirting system is an effective side seal that lies over the conveyor belt, without contact and creates negative pressure on the belt, due to its specially-designed lamella structure.
Because this system hovers freely above the conveyor belt, skirt friction and belt damage are eliminated and service life of every component of the conveyor is extended.
The AirScrape system encompasses inward facing, hardened-steel diagonal blades and operates according to a new principle where it hovers 1-2 mm, on the left and right side above the conveyor belt. These blades deflect larger particles inwards, while using the air-flow of the conveyor belt and conveyed material to create an inward suction, forcing any dust and fine particles back into the product flow. Through these diagonally fitted plates and the speed of the running belt, air is drawn from the outside inwards. As a result, neither the dust nor material can escape.
Conventional skirting is pressed against a conveyor belt to keep dust and material in the middle of the belt, but after a period, wear of the skirting and belt can be so severe, that material and dust escapes. Material spillage at transfer points needs to be removed and regular maintenance of belt skirting and transfer points is necessary.
With the AirScrape dust-free and contact-free, side-sealing system for belt conveyors, there is no skirt contact and therefore no belt wear or damage. Motor power requirements are reduced as there is no belt-skirt friction and because there is continuous skirting with no gaps, product loss is minimal.
This system is fitted using spacers, floating the blades just above the belt and is attached to the outside of the chute by utilising existing skirt clamps or a simple bolt and nut system. It is longitudinally adjustable to follow the contours of conveyor belt rollers and the belt trough angle.
The ST-Sure belt support system
The ST-Sure belt support system has been developed to avoid the problems of belt sag between the impact rollers. A smooth straight and flat belt surface keeps the AirScrape lamellas continuously in the correct position, with no physical belt contact.
TailScrape – the transfer tail skirting system
Like AirScrape, the TailScrape system works according to the Venturi concept, to prevent dust generation and material spills. The intelligent blade structure on the underside of the system ensures that negative pressure is created in the conveying area, preventing the escape of materials. Dust is kept in the material flow by air intake.
TailScrape is mounted precisely to the existing AirScrape system, so that it seals the transfer to the bend, averting dust generation and material spillage, also reducing the risk of explosion. The TailScrape system operates without contact to the conveyor belt, which means there is no belt or skirting wear and because the load on the drive system is reduced, there is no belt friction.
This system, which can be operated permanently, reduces maintenance requirements and replacement costs, also extending service life of components.
The BLT WORLD team, in close co-operation with ScrapeTec experts, provides an assessment and solutions service to customers in diverse sectors, for planning and implementing projects. A technical advisory and support service enhances performance of every ScrapeTec system.
