Panel that absorbs acoustic energy at low, medium and high frequencies, particularly at frequencies ranging from 400 Hz to 5,000 Hz
US5493081A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 29, 1994 |
| Grant date | Feb 20, 1996 |
| Priority date | — |
| Expiry date | Jul 29, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249981
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A panel absorbing acoustical energy at low, medium and high frequencies, particularly at frequencies ranging from 400 Hz to 5,000 Hz, is essentially constituted by a plate (1) of semi-rigid foam with open communicating cells and by a layer (2) of bonded fibers or by a flexible cellular material. The assembly acts according to a mass-spring principle. The plate (1) of semi-rigid foam with open communicating cells constitutes the mass of the assembly functioning according to the mass-spring principle, while the layer (2) of bonded fibers or of flexible cellular material constitutes the spring of this assembly. The foam comprising the plate (1) is preferably a semi-rigid polyurethane foam of a density ranging from 20 kg/m.sup.3 to 50 Kg/m.sup.3, of a thickness comprised between 5 mm and 15 mm and whose permeability to air is comprised between 5 liters per minute and 45 liters per minute for a specimen 80 mm in diameter. The layer (2) constituting the spring has a stiffness ranging from 0.007 MPa to 0.05 MPa and a thickness ranging from 4 mm to 10 mm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.