US4785909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise silencing systems
Assignee: Individual
•
Filing: 1985-04-02
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Granted: 1988-11-22
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Expires: 2005-04-02
Abstract
Abstract A silencer device having a substantially aperiodic (non-frequency-dependent) silencing action is provided. The silencer is of the flow type comprising an elongate chamber generally defining or surrounding an unobstructed fluid transmission path. The chamber is principally occupied by fluid having a predetermined characteristic impedance and is provided at both ends with acoustic energy absorbing means for providing acoustic impedance type terminations to said chamber, the acoustic impedance of the terminations being substantially equal to the characteristic impedance of the fluid in the chamber.
Inventors
- 👤 Robert E. Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:24
CPC Classifications
F; F01; F01N; F01N1/00; F01N1/08; F01N1/10; F01N1/24; F01N2310/00; F01N2310/14; F01N2470/00; F01N2470/30; F02; F02B; F02B1/00; F02B1/02; F02B1/04
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
127 words
A silencer device comprising an elongate chamber having two ends and generally defining a straight-line transmission path, said transmission path leading generally from one end of the chamber to the other, and being substantially uninterrupted by physical obstruction, the chamber being provided adjacent said ends with inlet and outlet apertures defining paths of entry to and exit from the chamber and communicating with the transmission path to provide a through-going transmission path, the chamber being principally occupied by a fluid having a predetermined characteristic impedance and being provided, at said ends, with acoustic energy absorbing means for providing energy dissipating acoustic impedance type terminations to said chamber, the acoustic impedance of the said terminations being substantially equal to the characteristic impedance of the fluid in the chamber.
Claim 2
Dependent Claim
127 words
A silencer device comprising an elongate chamber having two ends and generally defining a straight-line transmission path, said transmission path leading generally from one end of the chamber to the other, and being substantially uninterrupted by physical obstruction, the chamber being provided adjacent said ends with inlet and outlet apertures defining paths of entry to and exit from the chamber and communicating with the transmission path to provide a through-going transmission path, the chamber being principally occupied by a fluid having a predetermined characteristic impedance and being provided, at said ends, with acoustic energy absorbing means for providing energy dissipating acoustic impedance type terminations to said chamber, the acoustic impedance of the said terminations being substantially equal to the characteristic impedance of the fluid in the chamber.
Claim 3
Dependent Claim
26 words
A silencer as claimed in claim 1, wherein the terminations comprise a filament which is knitted, woven or crumpled together to form acoustic energy absorbing pads.
Claim 4
Dependent Claim
27 words
A silencer as claimed in claim 1, wherein the terminations comprise a metallic filament which is knitted, woven or crumpled together to form acoustic energy absorbing pads.
Claim 5
Dependent Claim
55 words
A silencer as claimed in claims 2 or 3, wherein the chamber is substantially cylindrical and is provided at each end with one or more acoustic energy absorbing pads, and where the paths of entry to, or exit from the chamber are substantially perpendicular to the straight-line transmission path of the fluid to be silenced.
Claim 6
Dependent Claim
23 words
A silencer as claimed in claim 4, wherein one end of the chamber is tapered towards one of the acoustic energy absorbing pads.
Claim 7
Dependent Claim
16 words
A silencer as claimed in claim 4, wherein the acoustic energy absorbing pads are convexly shaped.
Claim 8
Dependent Claim
31 words
A silencer as claimed in claim 4, wherein acoustic energy absorbing pads are further provided on an internal surface of said chamber facing said inlet and outlet apertures of said chamber.
Claim 9
Dependent Claim
31 words
A silencer as claimed in claim 1, wherein the chamber includes small raised formations on an internal surface thereof to give a combination of break-up and lossy action on sound patterns.
Claim 10
Dependent Claim
27 words
A silencer as claimed in claim 8, wherein the small formations are provided by a helix of increasing pitch lying against the internal surface of the chamber.
Claim 11
Dependent Claim
23 words
A silencer as claimed in claim 1, wherein the terminations comprise a screen-folded gauze or mesh to provide said acoustic energy absorbing means.
Claim 12
Dependent Claim
109 words
A silencer device comprising a transmission pipe having an inlet end and an outlet end generally defining a through-going transmission path for fluid to be silenced, the transmission pipe being surrounded by an annulus comprising an elongate shunt chamber, the chamber and the transmission pipe being acoustically coupled by apertures in the transmission pipe, the chamber being principally occupied by a fluid having a predetermined characteristic impedance and being provided at both ends thereof with acoustic energy absorbing means for providing energy dissipating acoustic impedance type terminations to said chamber, the acoustic impedance of the terminations being substantially equal to the characteristic impedance of the fluid in the chamber.
Claim 13
Dependent Claim
109 words
A silencer device comprising a transmission pipe having an inlet end and an outlet end generally defining a through-going transmission path for fluid to be silenced, the transmission pipe being surrounded by an annulus comprising an elongate shunt chamber, the chamber and the transmission pipe being acoustically coupled by apertures in the transmission pipe, the chamber being principally occupied by a fluid having a predetermined characteristic impedance and being provided at both ends thereof with acoustic energy absorbing means for providing energy dissipating acoustic impedance type terminations to said chamber, the acoustic impedance of the terminations being substantially equal to the characteristic impedance of the fluid in the chamber.
Claim 14
Dependent Claim
26 words
A silencer as claimed in claim 11, wherein the terminations comprise a filament which is knitted, woven or crumpled together to form acoustic energy absorbing pads.
Claim 15
Dependent Claim
27 words
A silencer as claimed in claim 11, wherein the terminations comprise a metallic filament which is knitted, woven or crumpled together to form acoustic energy absorbing pads.
Claim 16
Dependent Claim
24 words
A silencer as claimed in claim 11, wherein the terminations comprise a screen-folded metallic gauze or mesh to provide said acoustic energy absorbing means.
Claim 17
Dependent Claim
29 words
A silencer as claimed in claims 12 or 13, wherein the chamber is substantially cylindrical and is provided at each end with one or more acoustic energy absorbing pads.
Claim 18
Dependent Claim
23 words
A silencer as claimed in claim 15, wherein one end of the chamber is tapered towards one of the acoustic energy absorbing pads.
Claim 19
Dependent Claim
16 words
A silencer as claimed in claim 15, wherein the acoustic energy absorbing pads are convexly shaped.
Claim 20
Dependent Claim
25 words
A silencer as claimed in claim 11, wherein a venturi reduction is included in the transmission pipe to increase the acoustic coupling to the chamber.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-11-22 | 1992-05-23 | 1992-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-11-22 | 1996-05-23 | 1996-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-11-22 | 2000-05-23 | 2000-11-22 | $7700.00 | Window Closed / Lapsed |