Constant pressure device
US4657108A · kind A · utility
54Cited by
6References
16Claims
0Family size
Inventor
Key dates
| Filing date | Nov 2, 1984 |
| Grant date | Apr 14, 1987 |
| Priority date | — |
| Expiry date | Nov 2, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R1/2803
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A pressure modifying device and method which utilizes a gas or vapor and an adsorbent material to reduce the amplitude of pressure variations in gas or vapor. The technique is applicable to loudspeaker assemblies having a box (2), low frequency loudspeaker (16) and a mass (20) of activated charcoal in the box. Excursions of the cone (18) of the loudspeaker in the range 20 to 100 Hz cause pressure fluctuations in the air in the box but the size of those pressure fluctuations is comparatively small owing to increased air adsorption on the activated charcoal leading to increased efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.