Patent US1889577A successfully refreshed from Google Patents.
Patent US2625044A successfully refreshed from Google Patents.
US3955643A
Expired / Lapsed
US
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Free flow sound attenuating device and method of making
Assignee: Technetics Corp
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Filing: 1974-07-03
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Granted: 1976-05-11
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Expires: 1994-07-03
Abstract
Abstract An improved sound attenuating device characterized by several novel structures which include (1) a foraminous conduit covered by (2) a layer of sound absorbing material of increasing static flow resistance from the inlet end to the outlet end, and (3) a housing surrounding the conduit and defining a plurality of quarter-wave standing wave cavities in series after the inlet end in operative association with the covered conduit. The present structure provides an attenuating device having a continually changing flow resistance to match the decreasing sound pressure level of the fluid flow passing through the attenuator. The structure takes advantage of the interaction that exists between the sound pressure level and changes in the static and dynamic flow resistance, such that for decreasing sound pressure levels, the dynamic flow resistance will be maintained at an optimum for the system by increasing the static flow resistance.
Inventors
- 👤 Raymond C. Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:45
CPC Classifications
F; F01; F01N; F01N1/00; F01N1/003; F01N1/006; F01N1/02; F01N1/04; F01N2450/00; F01N2450/06; F01N2490/00; F01N2490/15; F01N2490/155
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
106 words
A device for attenuating the sound level in a fluid flowing therethrough, comprising: a conduit with one end an inlet and the other end the outlet and having a central foraminous portion; a layer of sound absorbing material surrounding the foraminous portion of the conduit to define a covered conduit; the sound absorbing material having a static flow resistance continuously increasing from the inlet to the outlet of the covered conduit; and a housing surrounding the covered conduit and secured to the inlet and outlet to define a plurality of quarter-wave standing wave cavities in series after the inlet in operative association with the covered conduit.
Claim 2
Independent Claim
106 words
A device for attenuating the sound level in a fluid flowing therethrough, comprising: a conduit with one end an inlet and the other end the outlet and having a central foraminous portion; a layer of sound absorbing material surrounding the foraminous portion of the conduit to define a covered conduit; the sound absorbing material having a static flow resistance continuously increasing from the inlet to the outlet of the covered conduit; and a housing surrounding the covered conduit and secured to the inlet and outlet to define a plurality of quarter-wave standing wave cavities in series after the inlet in operative association with the covered conduit.
Claim 3
Dependent Claim
26 words
The device of claim 1 wherein the depth of the quarter-wave standing wave cavities is an odd multiple of one-quarter wavelength of the frequency of interest.
Claim 4
Dependent Claim
19 words
The device of claim 1 wherein the foraminous conduit has an effective impedance in the range 3-30 cgs rayls.
Claim 5
Dependent Claim
19 words
The device of claim 1 wherein the foraminous conduit has an effective impedance in the range 31-100 cgs rayls.
Claim 6
Dependent Claim
19 words
The device of claim 1 wherein the foraminous conduit has an effective impedance in the range 101-400 cgs rayls.
Claim 7
Dependent Claim
14 words
The device of claim 1 wherein the foraminous conduit is a laminated screen structure.
Claim 8
Dependent Claim
13 words
The device of claim 1 wherein the foraminous conduit is a perforated tube.
Claim 9
Dependent Claim
19 words
The device of claim 7 wherein the perforated tube is made of metal with metal fiber in the openings.
Claim 10
Dependent Claim
15 words
The device of claim 1 wherein the foraminous conduit is a metal fiber web structure.
Claim 11
Dependent Claim
26 words
The device of claim 9 wherein the metal fiber web structure has the inside surface thereof covered with a layer of fibers having a protective coating.
Claim 12
Dependent Claim
12 words
The device of claim 10 wherein the fibers are made of metal.
Claim 13
Dependent Claim
12 words
The device of claim 10 wherein the fibers are of organic material.
Claim 14
Dependent Claim
12 words
The device of claim 10 wherein the fibers are of ceramic material.
Claim 15
Dependent Claim
13 words
The device of claim 10 wherein the protective coating is an oxidation catalyst.
Claim 16
Dependent Claim
15 words
The device of claim 1 wherein the sound absorbing material is made of filamentary material.
Claim 17
Dependent Claim
11 words
The device of claim 15 wherein the material is metal filaments.
Claim 18
Dependent Claim
10 words
The device of claim 15 wherein the material is fiberglass.
Claim 19
Dependent Claim
11 words
The device of claim 15 wherein the material is organic filaments.
Claim 20
Dependent Claim
13 words
The device of claim 1 wherein the sound absorbing material is knitted fabric.
Claim 21
Dependent Claim
13 words
The device of claim 19 wherein the fabric is formed from metal fibers.
Claim 22
Dependent Claim
16 words
The device of claim 1 wherein the layer of sound absorbing material has a constant thickness.
Claim 23
Dependent Claim
17 words
The device of claim 1 wherein the layer is a back and forth spiral overwrap of filaments.
Claim 24
Dependent Claim
10 words
The device of claim 22 wherein the filaments are metal.
Claim 25
Dependent Claim
10 words
The device of claim 23 wherein the filaments are sintered.
Claim 26
Independent Claim
104 words
A device for attenuating the sound level in a fluid flowing therethrough, comprising: a conduit with one end an inlet and the other end the outlet and having a central foraminous portion; a layer of sound absorbing material surrounding the foraminous portion of the conduit to define a covered conduit, the sound absorbing material having a continuously increase density from the inlet to the outlet of a covered conduit and, a housing surrounding the covered conduit and secured to the inlet and outlet to define a plurality of quarter-wave standing wave cavities in series after the inlet in operative association with the covered conduit.
Claim 27
Independent Claim
104 words
A device for attenuating the sound level in a fluid flowing therethrough, comprising: a conduit with one end an inlet and the other end the outlet and having a central foraminous portion; a layer of sound absorbing material surrounding the foraminous portion of the conduit to define a covered conduit, the sound absorbing material having a continuously increase density from the inlet to the outlet of a covered conduit and, a housing surrounding the covered conduit and secured to the inlet and outlet to define a plurality of quarter-wave standing wave cavities in series after the inlet in operative association with the covered conduit.
Claim 28
Dependent Claim
16 words
The device of claim 25 wherein the layer of sound absorbing material has a constant thickness.
Claim 29
Dependent Claim
17 words
The device of claim 25 wherein the layer is a back and forth spiral overwrap of filaments.
Claim 30
Dependent Claim
10 words
The device of claim 27 wherein the filaments are metal.
Claim 31
Dependent Claim
10 words
The device of claim 28 wherein the filaments are sintered.
Claim 32
Independent Claim
103 words
A device for attenuating the sound level in a fluid flowing therethrough, comprising: a conduit with one end an inlet and the other end the outlet and having a central foraminous portion; a layer of sound absorbing material surrounding the foraminous portion of the conduit to define a covered conduit, the sound absorbing material continuously increasing in thickness from the inlet to the outlet of the covered conduit; and, a housing surrounding the covered conduit and secured to the inlet and outlet to define a plurality of quarter-wave standing wave cavities in series after the inlet in operative association with the covered conduit.
Claim 33
Independent Claim
103 words
A device for attenuating the sound level in a fluid flowing therethrough, comprising: a conduit with one end an inlet and the other end the outlet and having a central foraminous portion; a layer of sound absorbing material surrounding the foraminous portion of the conduit to define a covered conduit, the sound absorbing material continuously increasing in thickness from the inlet to the outlet of the covered conduit; and, a housing surrounding the covered conduit and secured to the inlet and outlet to define a plurality of quarter-wave standing wave cavities in series after the inlet in operative association with the covered conduit.
Claim 34
Dependent Claim
26 words
The device of claim 30 wherein the sound absorbing material has a static flow resistance increasing from the inlet to the outlet of the covered conduit.
Claim 35
Dependent Claim
24 words
The device of claim 30, wherein the sound absorbing material has an increasing density from the inlet to the outlet of the covered conduit.
Claim 36
Independent Claim
160 words
A method of making a device for attenuating the sound level in a fluid flowing therethrough, comprising the steps of: providing a conduit with one end being the inlet and the other end the outlet, the conduit having a central foraminous portion between the inlet and outlet; applying a sound absorbing material on the periphery of the foraminous portion of the conduit to define a covered conduit, the sound absorbing material having a static flow resistance continuously increasing from the inlet to the outlet of the covered conduit; providing a housing around the covered conduit, the housing secured to the conduit at the inlet and outlet ends, the housing defining a space between the covered conduit and the housing; and, providing a plurality of plates in the space between the covered conduit and inner surface of the housing to define a plurality of quarter-wave standing wave cavities in series after the inlet end in operative association with the covered conduit.
Claim 37
Independent Claim
160 words
A method of making a device for attenuating the sound level in a fluid flowing therethrough, comprising the steps of: providing a conduit with one end being the inlet and the other end the outlet, the conduit having a central foraminous portion between the inlet and outlet; applying a sound absorbing material on the periphery of the foraminous portion of the conduit to define a covered conduit, the sound absorbing material having a static flow resistance continuously increasing from the inlet to the outlet of the covered conduit; providing a housing around the covered conduit, the housing secured to the conduit at the inlet and outlet ends, the housing defining a space between the covered conduit and the housing; and, providing a plurality of plates in the space between the covered conduit and inner surface of the housing to define a plurality of quarter-wave standing wave cavities in series after the inlet end in operative association with the covered conduit.
Claim 38
Dependent Claim
30 words
The method of making the device of claim 33 wherein the amount of sound absorbing material applied increases in thickness from the inlet to the outlet of the covered conduit.
Claim 39
Dependent Claim
35 words
The method of making the device of claim 33 further including the step of compression rolling the sound absorbing material with increasing pressure from the inlet end to the outlet end of the covered conduit.
Claim 40
Independent Claim
168 words
A method of making a device for attenuating the sound level in a fluid flowing therethrough, comprising the steps of: providing a conduit with one end being the inlet and the other end the outlet, the conduit having a central foraminous portion between the inlet and outlet; applying a sound absorbing material on the periphery of the foraminous portion of the conduit to define a covered conduit; providing a housing around the covered conduit, the housing secured to the conduit at the inlet and outlet ends, the housing defining a space between the covered conduit and housing; compression rolling the sound absorbing material with increased pressure from the inlet to the outlet of the covered conduit, thereby increasing the density and static flow resistance of the material; and, providing a plurality of plates in the space between the covered conduit and inner surface of the housing to define a plurality of quarter-wave standing wave cavities in series after the inlet end in operative association with the covered conduit.
Claim 41
Independent Claim
168 words
A method of making a device for attenuating the sound level in a fluid flowing therethrough, comprising the steps of: providing a conduit with one end being the inlet and the other end the outlet, the conduit having a central foraminous portion between the inlet and outlet; applying a sound absorbing material on the periphery of the foraminous portion of the conduit to define a covered conduit; providing a housing around the covered conduit, the housing secured to the conduit at the inlet and outlet ends, the housing defining a space between the covered conduit and housing; compression rolling the sound absorbing material with increased pressure from the inlet to the outlet of the covered conduit, thereby increasing the density and static flow resistance of the material; and, providing a plurality of plates in the space between the covered conduit and inner surface of the housing to define a plurality of quarter-wave standing wave cavities in series after the inlet end in operative association with the covered conduit.
Claim 42
Dependent Claim
32 words
The method of making the device of claim 36 wherein the sound absorbing material has a static flow resistance increasing from the inlet end to the outlet end of the covered conduit.
Claim 43
Independent Claim
142 words
A method of making a device for attenuating the sound level in a fluid flowing therethrough, comprising the steps of: providing a conduit with one end being the inlet and the other end the outlet, the conduit having a central foraminous portion between the inlet and outlet. spirally winding a filamentary material in a back and forth overlapped fashion on the exterior surface of the foraminous portion of the conduit to form a sound absorbing layer covering the conduit and having a preselected static flow resistance; providing a housing around the covered conduit, and secured thereto at the inlet and outlet defining a space there between; and, providing a plurality of plates in the space between the covered conduit and the inner surface of the housing to define the plurality of quarter-wave standing wave cavities in operative association with the covered conduit
Claim 44
Independent Claim
142 words
A method of making a device for attenuating the sound level in a fluid flowing therethrough, comprising the steps of: providing a conduit with one end being the inlet and the other end the outlet, the conduit having a central foraminous portion between the inlet and outlet. spirally winding a filamentary material in a back and forth overlapped fashion on the exterior surface of the foraminous portion of the conduit to form a sound absorbing layer covering the conduit and having a preselected static flow resistance; providing a housing around the covered conduit, and secured thereto at the inlet and outlet defining a space there between; and, providing a plurality of plates in the space between the covered conduit and the inner surface of the housing to define the plurality of quarter-wave standing wave cavities in operative association with the covered conduit
Claim 45
Dependent Claim
14 words
The method of claim 38 wherein the filamentary material is made from metal fibers.
Claim 46
Dependent Claim
11 words
The method of claim 39 wherein the metal fibers are sintered.
Claim 47
Dependent Claim
12 words
The method of claim 38 wherein the density of layer is uniform.
Claim 48
Dependent Claim
13 words
The method of claim 38 wherein the density of the layer is non-uniform.
Claim 49
Dependent Claim
15 words
The method of claim 38 wherein the resistance varies from the inlet to the outlet.
Claim 50
Dependent Claim
15 words
The method of claim 38 wherein the resistance increases from the inlet to the outlet.
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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) | 1979-05-11 | 1979-11-10 | 1980-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-11 | 1983-11-10 | 1984-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-11 | 1987-11-10 | 1988-05-11 | $7700.00 | Window Closed / Lapsed |