US4903249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rigid foraminous microphone probe for acoustic measurement in turbulent flow
Assignee: Atmus Filtration Inc
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Filing: 1988-03-24
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Granted: 1990-02-20
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Expires: 2008-03-24
Abstract
Abstract A microphone probe for acoustic measurement in turbulent flow. The probe includes a tube having a closed end facing upstream with respect to the direction of sound propagation and a microphone is located in a downstream end of the tube. At least a portion of the length of the tube is composed of a rigid foraminous material containing a multiplicity of interconnected cells with the average cell size being less than 100 microns. In operation sound pressure fluctuations cause pressure waves to propagate through the cells to the inside of the tube and the sound pressure waves add constructively to create a high pressure sound at the microphone, while turbulent flow pressure fluctuations are essentially averaged out.
Inventors
- 👤 Richard H. Hoops
- 👤 Larry J. Eriksson
- 👤 Mark C. Allie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:10
CPC Classifications
G; G01; G01H; G01H3/00; G01H3/10; G01H3/12
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
70 words
A microphone probe for acoustical measurement in turbulent flow, comprising a tube to be disposed in a sound field and having a closed end facing a source of sound energy, a microphone disposed in said tube downstream in the direction of sound propagation of said closed end, at least a portion of the length of said tube being composed of a rigid foraminous material containing a multiplicity of interconnected cells.
Claim 2
Dependent Claim
70 words
A microphone probe for acoustical measurement in turbulent flow, comprising a tube to be disposed in a sound field and having a closed end facing a source of sound energy, a microphone disposed in said tube downstream in the direction of sound propagation of said closed end, at least a portion of the length of said tube being composed of a rigid foraminous material containing a multiplicity of interconnected cells.
Claim 3
Dependent Claim
17 words
The probe of claim 1, wherein said material has an average cell size less than 100 microns.
Claim 4
Dependent Claim
21 words
The probe of claim 1, wherein said material has an average cell size in the range of 20 to 35 microns.
Claim 5
Dependent Claim
12 words
The probe of claim 1, wherein said material is a plastic material.
Claim 6
Dependent Claim
13 words
The probe of claim 4, wherein said plastic material is high density polyethylene.
Claim 7
Dependent Claim
12 words
The probe of claim 4, wherein said plastic material is polyvinylidene fluoride.
Claim 8
Dependent Claim
12 words
The probe of claim 1, wherein said material is a sintered metal.
Claim 9
Dependent Claim
16 words
The probe of claim 1, wherein said material extends completely around the circumference of said length.
Claim 10
Dependent Claim
83 words
In combination, means defining a flow path for sound energy, a microphone probe comprising a tube disposed in said flow path and having a closed end facing the source of sound energy, a microphone disposed in said tube downstream in the direction of sound progation of said closed end, at least a portion of the length of said tube being composed of a rigid foraminouos plastic material containing a multiplicity of interconnected cells, said cells having an average size less than 100 microns.
Claim 11
Dependent Claim
83 words
In combination, means defining a flow path for sound energy, a microphone probe comprising a tube disposed in said flow path and having a closed end facing the source of sound energy, a microphone disposed in said tube downstream in the direction of sound progation of said closed end, at least a portion of the length of said tube being composed of a rigid foraminouos plastic material containing a multiplicity of interconnected cells, said cells having an average size less than 100 microns.
Claim 12
Dependent Claim
12 words
The probe of claim 9, wherein said material is high density polyethylene.
Claim 13
Dependent Claim
81 words
A microphone probe for acoustical measurement in turbulent flow, comprising a tube to be disposed in a sound field and having a closed end facing a source of sound energy, a microphone disposed in said tube downstream in the direction of sound propagation of said closed end, at least a portion of the length of said tube being composed of a rigid foraminous sintered metal containing a plurality of interconnected cells, said cells having an average size less than 100 microns.
Claim 14
Dependent Claim
81 words
A microphone probe for acoustical measurement in turbulent flow, comprising a tube to be disposed in a sound field and having a closed end facing a source of sound energy, a microphone disposed in said tube downstream in the direction of sound propagation of said closed end, at least a portion of the length of said tube being composed of a rigid foraminous sintered metal containing a plurality of interconnected cells, said cells having an average size less than 100 microns.
Claim 15
Dependent Claim
12 words
The probe of claim 11, wherein said sintered metal is stainless steel.
Claim 16
Dependent Claim
21 words
The probe of claim 1, wherein said tube has a wall thickness in the range of 1/8 inch to 1/4 inch.
Claim 17
Dependent Claim
141 words
In an acoustic system having an input for receiving an input acoustic wave and an output for radiating an output acoustic wave, an active attenuation system for attenuating undesirable output acoustic wave, comprising an output speaker introducing a cancelling acoustic wave; an error microphone probe for sensing the combined said output acoustic wave and said cancelling acoustic wave from said output speaker and providing an error signal, said microphone probe comprising a tube having a closed end facing said input acoustic wave, a microphone disposed in said tube downstreaam of said closed end, at least a portion of the length of said tube being composed of a rigid formaminous material containing a multiplicity of interconnected cells, and an adaptive filter model adaptively modelling said acoustic system and outputting a correction signal to said output speaker to introduce said cancelling acoustic wave.
Claim 18
Dependent Claim
141 words
In an acoustic system having an input for receiving an input acoustic wave and an output for radiating an output acoustic wave, an active attenuation system for attenuating undesirable output acoustic wave, comprising an output speaker introducing a cancelling acoustic wave; an error microphone probe for sensing the combined said output acoustic wave and said cancelling acoustic wave from said output speaker and providing an error signal, said microphone probe comprising a tube having a closed end facing said input acoustic wave, a microphone disposed in said tube downstreaam of said closed end, at least a portion of the length of said tube being composed of a rigid formaminous material containing a multiplicity of interconnected cells, and an adaptive filter model adaptively modelling said acoustic system and outputting a correction signal to said output speaker to introduce said cancelling acoustic wave.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |