Patent US3630307A successfully refreshed from Google Patents.
US3630307A
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Mechanism and method for measuring sound absorption
Assignee: Rohr Inc
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Filing: 1969-08-01
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Granted: 1971-12-28
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Expires: 1989-08-01
Abstract
Abstract An electromagnetic tone generator transmits a tone burst comprising sound waves of known wavelength and intensity into one end of a tube, the other end of which tube is fitted against the surface of a material which reflects the sound waves back along the interior of the tube with a reduction in intensity proportional to their loss of acoustical energy. A microphone is exposed interiorly of the tube at a known distance from each end of the tube. Electronic time delay and gate circuitry feed into a monitoring circuit the electrical oscillations from the microphone produced by a selected series of clear sound waves of the original and the reflected sound bursts for a comparison of amplitudes.
Inventors
- 👤 Edwin C Kamps
- 👤 Irwin A Glibbery
- 👤 Billy G Cook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:52
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/04; G01N29/11
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
195 words
A mechanism for determining sound absorption properties of an acoustical material comprising: a tube of known minimum length and internal diameter, an acoustical transducer mounted on one end of the tube to transmit lengthwise into the tube a succession of tone bursts of known wavelength and sound pressure level, the other end of the tube being open and shaped to fit against a material to be tested with the tube axis at its open end normal to the material, whereby the material reflects back along the interior of the tube the tone burst transmitted by the acoustical transducer, a microphone exposed interiorly of the tube a selected distance from the open end of the tube, a readout monitor, and a circuit comprising circuit element elements controlling the duration and recurrence frequency of the tone bursts, and time delay and gate circuit elements constructed and arranged to communicate the microphone with the monitor for readout of the intensity of a pulse transduced by the microphone from a tone burst only during the passage of a selected series of sound waves of an original tone burst and the reflected counterparts of said selected series past the microphone.
Claim 2
Dependent Claim
195 words
A mechanism for determining sound absorption properties of an acoustical material comprising: a tube of known minimum length and internal diameter, an acoustical transducer mounted on one end of the tube to transmit lengthwise into the tube a succession of tone bursts of known wavelength and sound pressure level, the other end of the tube being open and shaped to fit against a material to be tested with the tube axis at its open end normal to the material, whereby the material reflects back along the interior of the tube the tone burst transmitted by the acoustical transducer, a microphone exposed interiorly of the tube a selected distance from the open end of the tube, a readout monitor, and a circuit comprising circuit element elements controlling the duration and recurrence frequency of the tone bursts, and time delay and gate circuit elements constructed and arranged to communicate the microphone with the monitor for readout of the intensity of a pulse transduced by the microphone from a tone burst only during the passage of a selected series of sound waves of an original tone burst and the reflected counterparts of said selected series past the microphone.
Claim 3
Dependent Claim
65 words
A mechanism as claimed in claim 1 wherein the distance from the microphone to the open end of the tube is sufficient to permit readout of the selected series of sound waves from an original tone burst before of the first of the same selected series of sound waves are reflected back to the microphone by material positioned across the open end of the tube.
Claim 4
Dependent Claim
31 words
A mechanism as claimed in claim 1 wherein the internal diameter of the tube is not greater than one-fourth the wavelength of the sound waves of an original tone burst transmitted.
Claim 5
Dependent Claim
39 words
A mechanism as claimed in claim 1 wherein the duration of an original sound burst is not greater than the time required for the selected portion thereof to travel between the microphone and the open end of the tube.
Claim 6
Dependent Claim
17 words
A mechanism as claimed in claim 1 wherein at least a portion of the tube is flexible.
Claim 7
Dependent Claim
28 words
A mechanism as claimed in claim 1 wherein the actuation of the time delay and gate circuit elements is initiated concurrently with the initiation of each tone burst.
Claim 8
Dependent Claim
17 words
A mechanism as claimed in claim 1 wherein at least a portion of the tube is coiled.
Claim 9
Dependent Claim
13 words
A mechanism as claimed in claim 1 wherein the tube is resiliently flexible.
Claim 10
Independent Claim
144 words
The method of determining sound absorption properties of an acoustic material which comprises projecting a tone burst of known wavelength, sound pressure level, and duration Through air or other gas along a restricted path past a microphone exposed in said path, and toward a sample of material having undetermined sound absorption properties positioned across said path a known distance beyond the microphone and normal to said path for reflecting said tone burst back along the same path, measuring the amplitude of a selected portion of the pulse transduced by the microphone from the original tone burst, measuring also the amplitude of the pulse transduced by the microphone from the reflection by said material of the same selected portion of said pulse, and comparing the amplitude of the selection portions of the pulse transduced by the microphone from the original and the reflected portions thereof.
Claim 11
Independent Claim
144 words
The method of determining sound absorption properties of an acoustic material which comprises projecting a tone burst of known wavelength, sound pressure level, and duration Through air or other gas along a restricted path past a microphone exposed in said path, and toward a sample of material having undetermined sound absorption properties positioned across said path a known distance beyond the microphone and normal to said path for reflecting said tone burst back along the same path, measuring the amplitude of a selected portion of the pulse transduced by the microphone from the original tone burst, measuring also the amplitude of the pulse transduced by the microphone from the reflection by said material of the same selected portion of said pulse, and comparing the amplitude of the selection portions of the pulse transduced by the microphone from the original and the reflected portions thereof.
Claim 12
Independent Claim
121 words
The method of determining sound absorption properties of an acoustic material which comprises projecting a tone burst of known wavelength, sound pressure level, and duration into one end of a tube, past a microphone exposed interiorly of the tube toward a material positioned a known distance beyond the microphone and normal to the axis of the tube at the other end of the tube for reflecting said sound burst back along the interior of the tube, measuring the amplitude of a selected portion of the pulse transduced by the microphone from the original tone burst, and measuring also the amplitude of the pulse transduced by the microphone from the reflection by said material of the same selected portion of said pulse.
Claim 13
Independent Claim
121 words
The method of determining sound absorption properties of an acoustic material which comprises projecting a tone burst of known wavelength, sound pressure level, and duration into one end of a tube, past a microphone exposed interiorly of the tube toward a material positioned a known distance beyond the microphone and normal to the axis of the tube at the other end of the tube for reflecting said sound burst back along the interior of the tube, measuring the amplitude of a selected portion of the pulse transduced by the microphone from the original tone burst, and measuring also the amplitude of the pulse transduced by the microphone from the reflection by said material of the same selected portion of said pulse.
References Cited (Backward Citations)
US3327806A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |