Filter
US7857885B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 2007 |
| Grant date | Dec 28, 2010 |
| Priority date | — |
| Expiry date | Apr 9, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S55/30
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A column shaped filter having a honeycomb structure including a number of through holes extending parallel with one another in the length direction with wall portion interposed therebetween. The through holes are constituted by large-capacity through holes having a relatively larger cross-sectional area in the cross section perpendicular to the length direction and small-capacity through holes having a relatively smaller cross-sectional area in the cross section. The numbers of the two types of through holes are substantially set to the same. The large-capacity through holes are sealed at one end of the filter, while the small-capacity through holes are sealed at the other end of the filter. The large-capacity and small-capacity through holes have a ratio of partition wall length, α, and an aperture ratio, β, and α and β satisfy β≧(20/9)α2+1 (where 0<α≦1.5 and 1<β≦6).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.