US3568791A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air ducting
Assignee: The University of Sydney
•
Filing: 1969-02-25
•
Granted: 1971-03-09
•
Expires: 1989-02-25
Abstract
Abstract A noise attenuator for inserting into the air ducting of an airconditioning or ventilating system which consists of a section of air ducting divided into at least two channels which differ from one another in length by an odd number of halves or quarters of the wave length of the predominant sound wave which is to be suppressed or diminished.
Inventors
- 👤 Russell E Luxton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:37
CPC Classifications
F; F24; F24F; F24F13/00; F24F13/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
71 words
A noise attenuator for insertion in the air ducting of an air-conditioning or ventilation system, comprising a section of air ducting divided into at least two channels which differ from one another in length by an odd number of halves of the wavelength of the predominant sound wave which is to be attenuated, and a profiled center body positioned within the section and which divides the section into the two channels.
Claim 2
Dependent Claim
71 words
A noise attenuator for insertion in the air ducting of an air-conditioning or ventilation system, comprising a section of air ducting divided into at least two channels which differ from one another in length by an odd number of halves of the wavelength of the predominant sound wave which is to be attenuated, and a profiled center body positioned within the section and which divides the section into the two channels.
Claim 3
Dependent Claim
22 words
A noise attenuator according to claim 1, in which the length of the shorter channel is approximately one-quarter of the predominant wavelength.
Claim 4
Dependent Claim
25 words
A noise attenuator according to claim 1, in which the length of the shorter channel is an odd number of quarters of the predominant wavelength.
Claim 5
Dependent Claim
22 words
A noise attenuator as claimed in claim 1 in which the profiled center body is a hollow structure made from rigid material.
Claim 6
Dependent Claim
19 words
A noise attenuator as claimed in claim 4, in which the hollow body is filled with sound absorbent material.
Claim 7
Dependent Claim
38 words
A noise attenuator as claimed in claim 1 in which the profiled center body is cast from a material selected from the group consisting of fibrous plaster, foam rubber, polyurethane foam and other castable material having acoustic-absorbing characteristics.
Claim 8
Dependent Claim
38 words
A noise attenuator as claimed in claim 1 in which the profiled center body is cast from a material selected from the group consisting of fibrous plaster, foam rubber, polyurethane foam and other castable material having acoustic-absorbing characteristics.
Claim 9
Dependent Claim
32 words
A noise attenuator as claimed in claim 1 in which the profiled center body is formed from a material selected from the group consisting of acoustic tiles, acoustic board and perforated material.
Claim 10
Dependent Claim
23 words
A noise attenuator as claimed in claim 1 in which the center body consists of a metal frame over which cloth is stretched.
Claim 11
Dependent Claim
23 words
A noise attenuator as claimed in claim 1 in which the center body consists of a metal frame over which cloth is stretched.
Claim 12
Dependent Claim
45 words
A noise attenuator as claimed in claim 1 in which the profiled center body is cut from a series of sheets selected from the group consisting of sheets of fibre glass board and sheets of other sound absorbing sheet material, which sheets are laminated together.
References Cited (Backward Citations)
DE178815C
Cited
GB121212A
Cited
FR602160A
Cited
US2027359A
Cited
FR869343A
Cited
FR910922A
Cited
US2990906A
Cited
US3323305A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |