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United States Patent | 6,274,035 |
Yuan ,   et al. | August 14, 2001 |
This invention relates to compact, high efficiency filter medium for used in biological filters. Thin filter sheets provide large surface area for the colonization of bacteria. Stacking the filter sheets in layers or rolling the sheet upon itself produce uniform flow passages defined by the spacers on the filter sheets which prevent fluid from flowing through a few large passages and thus reducing the efficiency of the entire filter.
Inventors: | Yuan; Sidney W. K., Los Angeles, California; Yuan; Katherine K., Los Angeles, California; Yuan; Jacquelyn K., Los Angeles, California; Yuan; Chrystal S., Los Angeles, California |
Appl. No.: | 274855 |
Filed: | March 23, 1999 |
Current U.S. Class: | 210/150; 210/615 |
Intern'l Class: | C02F 003/00 |
Field of Search: | 210/615,150,151 |
4184946 | Jan., 1980 | Kato | 210/615. |
5089137 | Feb., 1992 | McKown | 210/150. |
5326475 | Jul., 1994 | Kent | 210/615. |
5348654 | Sep., 1994 | Fischer | 210/151. |