Keeping Multidrives Cool
"Our goal in 2000, with the first needle punch line starting up in May and the second in September, was to ensure a capability of producing 14 million lb of high quality, standard and proprietary fabric annually," says Jay Desai, president of ASF.
Building from scratch affords the opportunity to think about everything a company wants to accomplish in terms of efficiency and operation, according to Desai. The plant location, near the city of Jefferson, for example, puts ASF within just a few hours of its machinery and electrical vendors. Customers, OEMs and other textile manufacturers for ASF's geo-textile, agricultural and furniture/bedding fabrics are within easy reach, too.
The polypropylene fiber extrusion equipment, which takes up half of the facility, was set up first -- both as a vertical source of raw materials supply internally and for producing fiber to sell to other nonwovens manufacturers.
"We knew such a configuration -- the largest of its type for any U.S. fiber manufacturer -- would generate heat, and that keeping the system cool would help ensure optimal operation," says Mike Mauney, director of business development for Electric Systems Integrator LLC, Chattanooga, Tenn., the company that constructed the multidrives.
The multidrive operation is controlled from the master operator console (near the carder). Changes in control made from the console automatically cascade downstream process to process -- or changes can be made to individual machines. The feed station is controlled from a computer located inside the enclosure protecting the drives.
Planning for optimum efficiency and operation of all electrical and mechanical equipment ahead of building construction extended to the large multidrives, says Desai.
Cool Drives for Dependable OperationKeeping the computers that operate the 16 stand-alone ABB drives controlling the lines' feed stations was especially important. Given that central air was cost prohibitive, individual spot cooling units were considered for the three cabinets that house the drives, but that was too expensive, also. ASF, with the help of a local vendor, selected a 5,000-ton cooling unit from Carrier Corp., Syracuse, N.Y., as the best long-term solution.
With capacity to add more production lines, ASF uses half the capacity of the 5,000-ton unit, according to Ron Crescenti, ASF's plant manager. "The cost was a lot less with the big unit than the cumulative cost of smaller units," he says, "and there's built-in capacity to grow." The three drive cabinets (ranging in size from 6 x 3 x 8' to 6 x 3 x 75') are built on top of iron frames with vents at the top for additional cooling.
Running piping from the large cooling unit suspended 30' above the production floor to the end points of the frames was challenging, Crescenti says. "The central unit is 150' away, and you need long branch lines. That adds complexity." But even on the hot summer days common to northern Georgia, there have been no faults due to overheated drives. "The benefits are built right into the facility's infrastructure," he says.