Sound absorption with variable acoustic resistance means
US3991849A · kind A · utility
20Cited by
6References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1975 |
| Grant date | Nov 16, 1976 |
| Priority date | — |
| Expiry date | Jul 21, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24165
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A system for varying the acoustic resistance of an acoustical lining disposed in a duct of an air propulsor comprises a nonlinear sound suppression liner having a porous facing sheet overlying a plurality of cells, header means communicating with each of the cells and air pumping means for forcing a predetermined steady flow of air sequentially through the header means, the cells and the facing sheet to vary the acoustic resistance of the facing sheet to make it optimum for a selected sound level and airflow condition in the duct.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.