US5504281A
Expired / Lapsed
US
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Perforated acoustical attenuators
Assignee: 3M Co
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Filing: 1994-01-21
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Granted: 1996-04-02
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Expires: 2014-01-21
Abstract
Abstract The invention provides an acoustical attenuator comprising: a porous material comprised of particles sintered and/or bonded together at their points of contact, having at least a portion of pores continuously connected, wherein said porous material has an interstitial porosity of about 20 to about 60 percent, an average pore diameter of about 5 to about 280 micrometers, a tortuosity of about 1.25 to about 2.5, a density of about 5 to about 60 pounds per cubic foot, a modulus of about 12,000 pounds per square inch or above, wherein said porous material has at least one through hole and wherein said interstitial porosity, average pore diameter, density and modulus values are for the porous material in the absence of any through holes, wherein the average diameter of the through hole is greater than the average pore diameter.
Inventors
- 👤 Leland R. Whitney
- 👤 Thomas J. Scanlan
- 👤 Charles A. Marttila
- 👤 Joseph G. Mandell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:15
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/02
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
134 words
An acoustical attenuator comprising: a porous material comprised of particles sintered and/or bonded together at their points of contact, having at least a portion of pores continuously connected, wherein said porous material has an interstitial porosity of about 20 to about 60 percent, an average pore diameter of about 5 to about 280 micrometers, a tortuosity of about 1.25 to about 2.5, a density of about 5 to about 60 pounds per cubic foot, a modulus of about 12,000 pounds per square inch or above, wherein said porous material has at least one through hole and wherein said interstitial porosity, average pore diameter, density and modulus values are for the porous material in the absence of any through holes, wherein the average diameter of the through hole is greater than the average pore diameter.
Claim 2
Dependent Claim
134 words
An acoustical attenuator comprising: a porous material comprised of particles sintered and/or bonded together at their points of contact, having at least a portion of pores continuously connected, wherein said porous material has an interstitial porosity of about 20 to about 60 percent, an average pore diameter of about 5 to about 280 micrometers, a tortuosity of about 1.25 to about 2.5, a density of about 5 to about 60 pounds per cubic foot, a modulus of about 12,000 pounds per square inch or above, wherein said porous material has at least one through hole and wherein said interstitial porosity, average pore diameter, density and modulus values are for the porous material in the absence of any through holes, wherein the average diameter of the through hole is greater than the average pore diameter.
Claim 3
Dependent Claim
19 words
The attenuator of claim 1, wherein said through hole(s) have an average length of about 1/8 inch or greater.
Claim 4
Dependent Claim
19 words
The attenuator of claim 2, wherein said through hole(s) have an average length of about 1/2 inch or greater.
Claim 5
Dependent Claim
21 words
The attenuator of claim 1, wherein said through hole(s) have an average diameter of about 1/64 inch to about 6 inches.
Claim 6
Dependent Claim
21 words
The attenuator of claim 4, wherein said through hole(s) have an average diameter of about 1/16 inch to about 2 inches.
Claim 7
Dependent Claim
22 words
The attenuator of claim 1, wherein about 0.1 to about 90 percent of the surface area of the attenuator contains through hole(s).
Claim 8
Dependent Claim
14 words
The attenuator of claim 1, wherein said through holes are in a symmetrical pattern.
Claim 9
Dependent Claim
27 words
The attenuator of claim 1, wherein said through hole(s) cross-section has a shape selected from the group consisting of circular, rectangular, triangular, elliptical, square and slit shaped.
Claim 10
Dependent Claim
14 words
The attenuator of claim 1, wherein said through hole(s) are in an asymmetrical pattern.
Claim 11
Dependent Claim
23 words
The attenuator of claim 1, wherein the average length to diameter ratio of the through hole(s) ranges from about 1:1 to about 100:1.
Claim 12
Dependent Claim
19 words
The attenuator of claim 1 wherein said porous material has a average thickness of about 1/64 inch or greater.
Claim 13
Dependent Claim
18 words
The attenuator of claim 1 wherein said material has an average thickness of about 1/2 inch or greater.
Claim 14
Dependent Claim
15 words
The attenuator of claim 1 wherein the porous material contains a plurality of through holes.
Claim 15
Dependent Claim
142 words
An acoustical system comprising a sound source and an attenuator, the attenuator comprising: a porous material comprised of particles sintered and/or bonded together at their points of contact, having at least a portion of pores continuously connected, wherein said porous material has an interstitial porosity of about 20 to about 60 percent, an average pore diameter of about 5 to about 280 micrometers, a tortuosity of about 1.25 to about 2.5, a density of about 5 to about 60 pounds per cubic foot, a modulus of about 12,000 pounds per square inch or above, wherein said porous material has at least one through hole and wherein said interstitial porosity, average pore diameter, density and modulus values are for the porous material in absence of any through holes, wherein the average diameter of the through hole is greater than the average pore diameter.
Claim 16
Dependent Claim
142 words
An acoustical system comprising a sound source and an attenuator, the attenuator comprising: a porous material comprised of particles sintered and/or bonded together at their points of contact, having at least a portion of pores continuously connected, wherein said porous material has an interstitial porosity of about 20 to about 60 percent, an average pore diameter of about 5 to about 280 micrometers, a tortuosity of about 1.25 to about 2.5, a density of about 5 to about 60 pounds per cubic foot, a modulus of about 12,000 pounds per square inch or above, wherein said porous material has at least one through hole and wherein said interstitial porosity, average pore diameter, density and modulus values are for the porous material in absence of any through holes, wherein the average diameter of the through hole is greater than the average pore diameter.
Claim 17
Dependent Claim
23 words
The acoustical system of claim 14 wherein the sound source is a loudspeaker and the attenuator is a loudspeaker cabinet or loudspeaker housing.
Claim 18
Independent Claim
153 words
A method of of attenuating sound comprising the step of using an acoustical attenuator within an ambient medium, said acoustical attenuator comprising a porous material comprised of particles sintered and/or bonded together at their points of contact, having at least a portion of pores continuously connected, wherein said porous material has an interstitial porosity of about 20 to about 60 percent, an average pore diameter of about 5 to about 280 micrometers, a tortuosity of about 1.25 to about 2.5, a density of about 5 to about 60 pounds per cubic foot, a modulus of about 12,000 pounds per square inch or above, wherein said porous material has at least one through hole and wherein said interstitial porosity, average pore diameter, density and modulus values are for the porous acoustical material in the absence of any through holes, wherein the average diameter of the through hole is greater than the average pore diameter.
Claim 19
Independent Claim
153 words
A method of of attenuating sound comprising the step of using an acoustical attenuator within an ambient medium, said acoustical attenuator comprising a porous material comprised of particles sintered and/or bonded together at their points of contact, having at least a portion of pores continuously connected, wherein said porous material has an interstitial porosity of about 20 to about 60 percent, an average pore diameter of about 5 to about 280 micrometers, a tortuosity of about 1.25 to about 2.5, a density of about 5 to about 60 pounds per cubic foot, a modulus of about 12,000 pounds per square inch or above, wherein said porous material has at least one through hole and wherein said interstitial porosity, average pore diameter, density and modulus values are for the porous acoustical material in the absence of any through holes, wherein the average diameter of the through hole is greater than the average pore diameter.
Claim 20
Dependent Claim
22 words
The attenuator of claim 1, wherein about 0.5 to about 50 percent of the surface area of the attenuator contains through holes(s).
Claim 21
Dependent Claim
22 words
The attenuator of claim 1, wherein about 0.9 to about 25 percent of the surface area of the attenuator contains through hole(s).
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