Grede Holdings LLC has placed an order with Vibra Screw Inc. for a new Bin Activator discharge system, to process sand as it passes from bulk storage to the preparation stage for molding. What’s notable is that the new machine will be the first replacement of that device in 33 years. In 1979 Grede needed a machine to discharge sand reliably from a 10.5-ft square bin into a batch hopper at 56 tons/hour. The batch cycle time was 90 seconds, so maintaining a consistent full-bore discharge on demand was critical to efficient operation
Vibra Screw fabricated a square-to-round transition and an 8-ft diameter Bin Activator machine was fitted to the opening in the transition piece. The unit hangs from a mounting ring on the bin in a flexible arrangement involving rubber-bushed, forged-steel hanger arms that provide tensile strength to support a bin load of 90 lb/ft3, while isolating the bin from the vibration generated by the Bin Activator’s oillubricated gyrator. A molded, leakproof, flexible sleeve seals the gap between vibrating Bin Activator and the stationary mounted ring.
The Bin Activator machine was actually invented by Vibra Screw more than 50 years ago, in 1960. It includes an ASME dished head that offers both strength and durability for severe-duty applications, and its oil-lubricated gyrator is designed to perform for many years with minimal maintenance, generating multi-ton forces to move heavy, flow-resistant material — like foundry sand.
Though the 1979 machine has performed well with regular maintenance, Grede is replacing it because of the abrasive effects of sand over three decades of service. The manufacturer noted that hundreds of Bin Activators have been in service for similar lengths of time, or even longer. An identical 8-ft. bin will be installed for Grede soon – bringing the number of Vibra Screw machines in use by that ferrous foundry group to more than two dozen.