Overland Sand & Gravel/Ready Mix in York, Neb., is a large operation that supplies concrete locally and throughout central Nebraska from seven satellite facilities. The company buys its cement from a major supplier at a terminal on the east side of Omaha, 120 miles from the main plant. The two transport trailers that Overland operates can deliver 60,000 lbs. of cement per load. A round trip takes more than four hours, plus time for loading and unloading, making two loads per day the practical limit.

With the ever-tightening supply of cement, recent increases in diesel fuel prices and the difficulty of accommodating large pours, Overland's president, Merlyn Hanson, began searching for ways to improve powder delivery. Having previously purchased equipment from Cyclonaire Corp., also based in York, he turned to the company's engineers for ideas.

After studying the problem, Cyclonaire staff recommended using an existing rail spur located on several acres of land within three miles of Overland's main plant as a site for a simple railcar unloading station. Because the manufacturer could provide a compact pneumatic system that requires only one medium-pressure blower, this would be a low-cost mini terminal, and the facility could be expanded to handle future needs.

To balance Overland's delivery and budget goals, Cyclonaire designed the installation around a model HC-Series, semi-dense phase conveyor with 50-cu-ft. capacity. This mid-size unit allows unloading a hopper-bottom railcar without the need for a pit. Before unloading begins, a lightweight aluminum pan is clamped to the railcar hopper outlet flange and connected to the HC conveyor by a 6-in. vacuum hose.

Cyclonaire assembled the positive displacement blower, connecting piping and the HC Conveyor on a common skid to speed up field installation. Then, the skid and a Cyclonaire Dust Collector were placed on a slab foundation poured adjacent to the rail spur. Electrical equipment and a small air compressor for operating control valves completed the system. Cyclonaire semi-dense phase HC Conveyors use medium-pressure air to move materials at a balanced combination of intermediate line velocities and high material-to-air ratios to minimize abrasion and optimize conveying efficiency.

The HC's proprietary venturi creates the vacuum for drawing material from the railcar into the conveyor transfer tank. This eliminates both the extra filtration and vacuum pump required by conventional pneumatic systems. When the tank is full, a valve automatically switches, and the medium-pressure blower air carries the cement to Overland's transport trailer. System controls automatically count these load/unload cycles and stop the conveyor when the trailer is full. As it is being filled, the trailer is vented to the dust collector, and any cement dust carried to the collector's hopper is automatically sucked from the hopper at the end of the transloading operation and returned for use. No product is wasted, and Overland's drivers now have around-the-clock access to cement just five minutes away.

“Now we can fill a transport truck in an hour,” says Hanson, “The terminal more than doubles the cement we can feed to our plants every day…and it cuts our handling and product costs. Up to 10 cars fit on our rail spur, giving us flexible storage that we can calibrate to our workload.”
— Cyclonaire Corp., 888/593-6318; www.cyclonaire.com