Circular Screen Separators Handle Wastewater for Fiberglass Manufacturer

Nearly 15 years ago, a manufacturer of fiberglass used for building insulation, used lagoons to clarify its process wastewater. By installing six Kason VIBROSCREEN® circular screen separators and making other changes in its process in 1975, the company was able to form a closed loop processing system, making more efficient use of chemicals and water as well as eliminating the need for lagoons which eventually become filled and sometimes leak.

The manufacturing process involves heating silica sand and borax in a furnace and pouring the molten slurry into a vessel with an orifice. After flowing through the orifice, the hot strand or filament is cooled with a water/binder spray. The cooling spray falls into a large holding tank and then through 40 mesh prescreens. It is then pumped to a headbox with six outlets, each having a valve which is almost always open. Downstream of the valves are six 60 inch diameter VIBROSCREEN separators with 100 mesh stainless steel screens. Each unit handles about 300 to.500 GPM.

The 110 degree F wastewater has about 2% solids in the form of fiberglass strands. To keep the strands from blinding the screens, Kleen screen rings are placed underneath the screens. Since the strands are mainly silica, it is extremely abrasive.

The Kason stainless steel screens are usually providing about six months (approximately 4300 hours) of continuous service and the VIBROSCREEN units have operated without any failures since 1975. Except for maintenance during plant shutdown, these separators operate 24 hours per day, seven days per week.

The role of the separators is crucial to the process because if any strands get through the screens, the recycled process water would carry the strands to the spray nozzles where clogging would occur. As a result, the hot strands or filaments would not cool properly, leading to substandard fiberglass insulation.

Plans call for recycling the strands coming off the top of the screens to further minimize costs for raw material and waste treatment.

With adequate maintenance, it's almost always typical for Vibroscreen separator users to get years and years of trouble-free service. The gyrator motors are well designed units, sized correctly and incorporate heavy duty vibratory bearings.

By changing its process to a closed loop, the manufacturer has maintained high quality, cut cost for raw materials, and minimized its waste. Clearly, smart thinking and high quality process equipment have helped the company gain the competitive edge that is required to succeed in today's markets.

Screen Tips - Volume 4, Number 3 FALL 1989