ElectroFiltration Raises Filtration Efficiency for High-Purity Air in Materials Processing
ElectroFiltration Technologies, Inc. (EFT; Tampa, Fla.) has received U.S. patents on a "next-generation" technology in air filtration for semiconductor, pharmaceutical, chemical and food processing. EFT's ElectroFilter uses electrical forces to convert low-efficiency filters into high-efficiency ones without increasing pressure drop.
Laboratory tests show that 16 percent-efficient filters can reach 99.65 percent efficiency in removing particles as small as 0.19mm. Airborne microbes trapped on the filter are either killed or neutralized, and filter life is extended. When it becomes commercially available later this year, the ElectroFilter will find application in both environmental and process air filtration, for example: semiconductor and pharmaceutical clean rooms, chemical reactors, fermentations, and any process that requires particle-free air.
The ElectroFilter differs from conventional electrostatic precipitation, which uses a charged plate and a ground plate to attract particles. In electroprecipitation (EP), the plates themselves become the filter medium: particles build up on the plates, diminishing the inter-plate distance, eventually causing arcing. At best the filtration system must be shut down and cleaned. The ElectroFilter also uses a charged plate and a ground plate, but the purpose of these is to charge particles as they pass by and to polarize the filter as well. Particles then adhere to the filter medium, which is simply discarded when it becomes clogged.
Combining a filter with EP addresses the major drawback of conventional (non-electrostatic) industrial-strength air filters. "Existing high-efficiency filters have a very high resistance to air flow," says Stephen Hays, ElectroFiltration Chairman. "Resistance reduces airflow available for heating and cooling, and the filters tend to clog quite easily. Our technology allows you to turn almost any 16 percent-efficient filter into a 99 percent-plus efficient filter and decreases downtime associated with frequently changing filter media."
The ElectroFilter is now in the prototype stage. ElectroFiltration Technologies has performed extensive in-house testing on commercial filtration systems and has placed several units into commercial sites for evaluation.
By Angelo DePalma
For more information on the ElectroFilter contact: Sven Coppam, vice president, ElectroFiltration Technologies, Inc., 6395 Gunpark Drive, Suite S, Boulder, CO 80301. Phone: 303-530-4447.