Rock Products

JUL 2017

Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market

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24 • ROCK products • July 2017 mounted on the top of the loading chute, but the filters clogged so quickly, maintenance became burdensome." According to Whelpton, to maintain normal operation of the system and avoid serious hazards, the area needed to be cleaned by two workers once per week, requiring nearly an entire shift. Before engaging in what he described as a "substantial undertaking," the system would be shut down so workers could see. Anyone entering the enclosed area was required to wear personal protective equipment (PPE), including breathing masks with respirators and hooded suits to protect against airborne particles. Workers first had to clear thigh-deep piles of dust from walkways and around the mainframe using the plant's central industrial vacuum system, in order to access the conveyor for inspection and maintenance. "We needed a solution that bolstered safety and would deliver a return on investment in a reasonable amount of time," Smith said. "That meant installing highly effective equipment that needed as little ongoing maintenance as possible." Discovery Singleton Birch initially brought in Martin Engineering for conveyor training of 10 employees using its Foundations pro- gram and reference book. Now in its 4th edition, the 574-page volume teaches basic and advanced level conveyor system maintenance and safety. As part of the hands-on program, instructors took students on a walkthrough and created a report for several conveyors in the plant, including GLC1, where points of potential improvement were identified. These reports were then provided to plant supervisors. Since Martin Engineering has a division in nearby Not- tingham, managers asked local representatives to draft a proposed solution to the GLC1's issues. "A local contrac- tor and I took measurements and then created a detailed design overhaul," Kevill said. "The goal of our proposal was to contain the dust at the point of production by creating an environment that would quickly settle agitated particles and return them to the cargo flow. This would control spillage and improve air quality." Improved Loading Zone Design The first step of the plan was to raise and lengthen the existing chute to create a more robust settling zone. Using 2.5 metric tonnes (2.75 tons) of steel, the contractor fabricated a 4-m (13-ft.) chute extension and tail box. The overhaul integrated Martin ApronSeal Double Skirting HD and an EVO External Wear Liner to protect the chute wall and seal in dust. In addi- tion, a series of dust curtains was installed and the mechanical dust filtration system was cleared and put back into operation. In standard chute designs, the wear liner is a sacrificial layer securely welded to the inside of the chute, with the skirt seal located on the outside, a configuration that has presented operators with several costly problems. •  First, the internal placement of the wear liner creates a gap between the skirt seal and liner, in which material could get trapped and cause abrasion damage to the belt. •  Second, removal and replacement of most wear liner designs requires workers to enter the chute with a grinder and torch cut the worn equipment. The grueling and poten- tially dangerous job can take as many as three people up to two days of downtime to complete. The new design raised the chute 102 mm (4 in.) from its previous position to accommodate the EVO External Wear Liner. Mounting brackets with jackscrews provide a secure mount, with precision adjustment of the wear liner to reduce spillage. The system closes the gap between the liner and the sealer, thus eliminating abrasion from trapped material without interfering with existing supports. When accompa- nied by the Double Sided ApronSeal skirting and clamps, the Dust curtains are set throughout the chute to slow air flow and reduce fugitive particle emissions. The EVO External Wear Liner helps prevent damage to the chute wall. HANDLING DUST

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