US3692142A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spiral muffler
Assignee: COWL IND Ltd
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Filing: 1971-06-14
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Granted: 1972-09-19
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Expires: 1991-06-14
Abstract
Abstract A muffler or silencer having a spiral duct centrally disposed within a housing, with sound absorbent material between the ends of the housing and the ends of the spiral duct to reduce noise.
Inventors
- 👤 Leslie William Stemp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:59
CPC Classifications
F; F01; F01N; F01N1/00; F01N1/08; F01N1/12; F01N1/125
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
146 words
Apparatus for silencing an engine and the like, comprising: a. a housing having an inlet and an outlet, a side wall, two end walls, and a longitudinal axis, b. a spiral duct in said housing, said spiral duct having opposed ends, said spiral duct being positioned with its longitudinal axis parallel with the longitudinal axis of the housing, the ends of said spiral duct respectively being spaced inwardly from the end walls of the housing, said spiral duct having an inlet and an outlet, c. first duct means for conveying gases from the inlet of the housing to the inlet of the spiral duct, d. second duct means for conveying gases from the outlet of the spiral duct to the outlet of the housing, and e. sound absorbent material substantially filling the spaces between the ends of the spiral duct and the ends of the housing.
Claim 2
Dependent Claim
146 words
Apparatus for silencing an engine and the like, comprising: a. a housing having an inlet and an outlet, a side wall, two end walls, and a longitudinal axis, b. a spiral duct in said housing, said spiral duct having opposed ends, said spiral duct being positioned with its longitudinal axis parallel with the longitudinal axis of the housing, the ends of said spiral duct respectively being spaced inwardly from the end walls of the housing, said spiral duct having an inlet and an outlet, c. first duct means for conveying gases from the inlet of the housing to the inlet of the spiral duct, d. second duct means for conveying gases from the outlet of the spiral duct to the outlet of the housing, and e. sound absorbent material substantially filling the spaces between the ends of the spiral duct and the ends of the housing.
Claim 3
Dependent Claim
96 words
Apparatus as claimed in claim 1 wherein there are first and second spaced-apart, parallel bulkheads in said housing, said bulkheads being positioned to define a first compartment adjacent to one end wall of the housing, a second compartment adjacent to the first compartment, and a third compartment between the second compartment and the other of said end walls of the housing, said bulkheads having a plurality of openings through which gases may freely pass, said spiral duct being positioned in said second compartment and said sound absorbent material being placed in said first and third compartments.
Claim 4
Dependent Claim
62 words
Apparatus as claimed in claIm 2 wherein the inlet of the spiral duct is adjacent to the longitudinal axis of the housing, wherein the housing inlet and outlet are respectively positioned in the end walls of the housing, and wherein the second bulkhead is formed with an opening through which gases passing through the spiral duct outlet may enter the third compartment.
Claim 5
Dependent Claim
37 words
Apparatus as claimed in claim 2 wherein the side wall of the housing is cylindrical and encloses the second compartment, and the end walls of the housing are conical and respectively enclose the first and third compartments.
Claim 6
Dependent Claim
15 words
Apparatus as claimed in claim 2 wherein the bulkheads are formed of perforated metal sheet.
Claim 7
Dependent Claim
21 words
Apparatus as claimed in claim 2 wherein at least one wall of the spiral duct is lined with sound absorbent material.
Claim 8
Dependent Claim
55 words
Apparatus as claimed in claim 3 wherein there is a third bulkhead in the third compartment, the third bulkhead being positioned between the second bulkhead and the outlet, the third bulkhead forming one wall of an expansion chamber that is in communication with and positioned between the outlet of the housing and the third compartment.
Claim 9
Dependent Claim
36 words
Apparatus as claimed in claim 7 wherein the first bulkhead has a central opening, and wherein the first duct means comprises a pipe that is connected between the inlet of the housing and said central opening.
Claim 10
Dependent Claim
106 words
Apparatus for silencing an engine and the like, comprising: a. a housing having an inlet and an outlet, a side wall and two end walls, b. a spiral duct in said housing, said spiral duct having an inlet and an outlet, c. first duct means for conveying gases from the inlet of the housing to the inlet of the spiral duct, d. second duct means for conveying gases from the outlet of the spiral duct to the outlet of the housing, and e. sound absorbent material secured to at least one wall of said spiral duct and extending substantially the entire length of said spiral duct.
Claim 11
Dependent Claim
106 words
Apparatus for silencing an engine and the like, comprising: a. a housing having an inlet and an outlet, a side wall and two end walls, b. a spiral duct in said housing, said spiral duct having an inlet and an outlet, c. first duct means for conveying gases from the inlet of the housing to the inlet of the spiral duct, d. second duct means for conveying gases from the outlet of the spiral duct to the outlet of the housing, and e. sound absorbent material secured to at least one wall of said spiral duct and extending substantially the entire length of said spiral duct.
Claim 12
Dependent Claim
49 words
Apparatus as claimed in claim 9, wherein said sound absorbent material is applied to a wall of said spiral duct which is on the low pressure side of the gases flowing through the spiral duct, and said sound absorbent material extends substantially the entire length of said spiral duct.
Claim 13
Dependent Claim
21 words
Apparatus as claimed in claim 9, wherein all inner surfaces of said spiral duct are lined with said sound absorbent material.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-19 | 1976-03-20 | 1976-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-19 | 1980-03-20 | 1980-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-19 | 1984-03-20 | 1984-09-19 | $7700.00 | Window Closed / Lapsed |