Issue link: https://www.e-digitaleditions.com/i/1302781
48 / November 2020 powderbulk.com CASE HISTORY ADVERTISEMENT Of the 30 million scrap tires recycled into ground rubber in the US, some 6 million (20%) find their way to the Edge Rubber plant in Chambersburg, PA, the oldest and most successful facility produc- ing fine mesh crumb rubber in the United States. Much of the plant's efficiency is attributable to its bulk raw material handling system uti- lizing six Flexicon bulk bag dischargers and flexible screw conveyors. "On receiving the scrap tires, we first shred them into approx- imately ? in. (1.3 cm) particles, which are gravity fed into 2,000 lb (907 kg) bulk bags," says Sam Kauffman, Vice President and Chief Operating Officer of Edge Rubber. "These rough ground particles make up 80% of the raw material that we process into fine mesh crumb rubber." Moving the rubber particles from the bulk bags to the cracker mills are six automated Bulk-Out® BFC Bulk Bag discharger systems with integral flexible screw conveyors from Flexicon. An operator loads a bulk bag onto the discharger frame by electric hoist and trol- ley on a cantilevered I-beam; the discharger unloads the particles into a 20 cu ft (0.56 cu m) capacity floor hopper from which a 15 ft (4.57 m) long flexible screw conveyor transports them into one of six cracker mills. Kauffman explains, "Four of these discharger systems are identical, one has a larger diameter flexible screw conveyor for faster feeding capacity, and one is a double discharge unit with two flexible screw conveyors that feed material to two cracker mills." Once the bag is in place, the operator pulls the tied end through an iris valve, which prevents material flow while the bulk bag is being untied and allows controlled discharge of the material into the hopper once the bag has been opened. To ensure continuous flow of rubber particles from the bulk bag, Flow- Flexer® bag activation devices positioned on the frame con- tinually compress and release opposite sides of the bag, raising and lowering opposite bottom edges to promote flow through the bag spout into the floor hopper. The rubber particles flow from the discharge port of the floor hopper and charging adapter into the 15 ft (4.57 m) long Model 1450 flexible screw conveyor, designed to handle difficult materials. High and low level sen- sors in the floor hopper sig- nal a PLC to activate the con- veyor on reaching high level, and turn off the conveyor on reaching low level. "Thanks in large part to our bulk bag discharging equipment, we are one of the most efficient scrap rubber recycling plants in the United States," concludes Kauffman. SCRAP TIRES REDUCED TO CRUMB RUBBER WITH HELP OF FLEXICON DISCHARGERS, CONVEYORS Flexicon Corp. | 888-353-9426 | www.flexicon.com From the large hopper, two flexible screw conveyors transport ground rubber particles from the cracker mills to wet grind mills for the finest size reduction. Bulk bag discharger and flexible screw conveyor feed rough ground particles and rubber buffings to cracker mill. The bulk bag is loaded into the discharger frame by electric hoist and trolley suspended from a cantilevered I-beam. The wide frame accommodates open-bottom design bags.