Centrifugal screener delumps problems
Imagine increasing your screening rate from 4,000 lb/h to 4,000 pounds per 12 minutes by replacing just one piece of equipment in your processing line. Castek Inc., Berwick, Pa., did just that, increasing its process efficiency by 75 percent and solving a processing problem at the same time.
Castek, a subsidiary of Transpo Industries Inc., New York, produces 35- to 75-pound bags of high-compressivestrength polymer concrete for patching and concrete rehabilitation of roads, bridges, airport runways, and parking decks. To produce the polymer concrete, the company combines fine, abrasive silica sand with a liquid plasticizer to form a semisticky powder, which has a tendency to form lumps. The raw sand consists of unevenly shaped free-flowing granules ranging from fine to 1/16 inch. The sand is stored in computercontrolled storage silos, from which it’s pneumatically conveyed into a 7,000-pound-capacity pneumatic blender located on top of a 20-foot-tall mezzanine. Inside the blender, a liquid plasticizer is sprayed onto the sand to create the semisticky powder that can sometimes have soft lumps as large as 2 inches. The blended material drops into a boot located at the blender’s bottom and discharges via a 10-inch pipe outlet with a butterfly valve. A manually operated slide-gate valve in the pipe controls the material flowrate.