Electrically enhanced Filter (EEF)
- 1997 R&D 100 Award Winner
- 1996 Micro Product All Star
- 1995 NASA Technology 2000
SBIR Award Winner
enters the first high intensity ionizing field.
and bacteria are charged due to ion flux in this ionizing field- some
of the bacteria are killed here.
charged particles and bacteria are efficiently filtered due to
dielectrophoretic and electrophoretic forces and other conventional
filtration mechanisms –up to
1000 times lower penetration than conventional filters with the same
pressure drop and flow rate.
caught on the filter are continuously subjected to ionizing
EEF technology is extremely effective due to the use of two ionizing
high voltage is not applied directly to the filter –control
electrode prevents arcing towards the filter.
filters can often become a breeding ground for bacteria. Bacteria can
grow through the filters and shed in the cleanroom. Biocides on
filters are only effective as long as the filters are clean. The BIO
PLUS® filter system, however, continuously kills the bacteria caught on
the filters by means of ion bombardment, as demonstrated by the tests summarized
in Table I.
I: Antimicrobial (Staphylococcus epidermidis) tests using BIO
PLUS® and conventional filters.
high concentration of S. epidermidis was first sprayed on to
the filters as an aerosol.
four hours of air flow, the bacteria was extracted from the filters
using sterile phosphate buffered saline.
extract was diluted at various concentrations and growth media
plates were inoculated with it.
24 hours of incubation the colonies formed were counted and the
concentration on the filter media was calculated
of colonies/ sq. inch
A low restriction
filter’s performance is increased by using ionizing electrical fields,
resulting in bactericidal effects, low restriction, and reduced filter
penetration – by 2- 3 orders of magnitude! The result is high
performance with low noise. The lower pressure drop of EEF HEPA enables use
with a terminal HEPA in series resulting in 99.999999% filtration
April 1995, US Patent 5,403,383,
US patent 7,156,898B2, Jan 2007