Filter
US4257791A · kind A · utility
48Cited by
10References
27Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 10, 1979 |
| Grant date | Mar 24, 1981 |
| Priority date | — |
| Expiry date | Aug 10, 1999 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2279/60
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
There is provided a filter wherein the filtering means has a non-woven needled textile filter fabric with an overall bulk density of at least 6 pounds per cubic foot and bulk density gradient such that the bulk density at the face surface of the fabric is greater than the bulk density at the back surface of the fabric. In conjunction with that bulk density gradient is a filtering gradient such that the fineness of filtration at the back face surface is greater than the fineness of filtration at the surface. The filter may be in any convenient form, such as the bag of an air conveyor filter or a vacuum cleaner filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.