Filter for liquid and method of filtering liquid
US4948515A · kind A · utility
31Cited by
3References
22Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1988 |
| Grant date | Aug 14, 1990 |
| Priority date | — |
| Expiry date | Dec 22, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01G7/023
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method for filtering liquids having a dielectric constant less than 10 is disclosed. The method includes the step of filtering a liquid through a porous layer of an electret, the electret consisting of a fibrous sheet having a surface charge density of at least 5.times.10.sup.-11 coulombs/cm.sup.2, wherein on the upstream side of the electret is laminated another porous layer having at least a porosity or an average fiber diameter greater than that of the electret layer. The upstream layer may consist of either a fibrous electret layer, or an uncharged fibrous layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.