Patent US5427967A successfully refreshed from Google Patents.
Patent US3650094A successfully refreshed from Google Patents.
US3650094A
Expired / Lapsed
US
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Acoustical filtration system
Assignee: RTX Corp
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Filing: 1969-12-19
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Granted: 1972-03-21
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Expires: 1989-12-19
Abstract
Abstract A fluid medium containing suspended particles is subjected to an asymmetrical sound wave having a high velocity in one direction of movement and a low velocity in the opposite direction of movement. The velocities are sufficiently great to produce square-law drag forces; and the suspended particles will be propelled through the fluid medium in a direction corresponding to the high velocity direction of the fluid medium.
Inventors
- 👤 Raymond Wendell Goodwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:44
CPC Classifications
B; B08; B08B; B08B3/00; B08B3/04; B08B3/10; B08B3/12; B08B2203/00; B08B2203/002; G; G01; G01N; G01N30/00; G01N30/02
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
295 words
An acoustical filtration system comprising: a duct, adapted to receive a flow of a fluid containing suspended particles which are to be filtered from the fluid by said system, said duct comprising at least three substantially planar sound reflecting walls relatively disposed with respect to one another so that sound reflected from one wall to the adjacent wall will in turn be reflected to a subsequent wall thereby recirculating in a first plane substantially perpendicular to the fluid flow path through said duct; sound generating means for producing an oscillatory sonic signal characterized by a relatively high velocity in a first direction for a short portion of the period of said sonic wave and a relatively low velocity in an opposite direction for a relatively long portion of the period of said sonic wave in a predetermined mark-space ratio, said sound generating means disposed with respect to a wall of said duct so as to introduce into a fluid flowing within said duct a sound wave propagating in said first plane; a sound permeable, particle impermeable diaphragm disposed at a point in said duct so as to intersect said first plane, said diaphragm disposed in a second plane substantially parallel with the fluid flow passage through said duct and substantially perpendicular to said propagating sound waves; and inlet means disposed in proximity with a downstream portion of said diaphragm for withdrawing matter flowing along said diaphragm in said duct, said circulating sound waves producing at least a component of velocity in particles flowing within said duct which is transverse to said diaphragm and to the fluid flow path in said duct, whereby particles suspended in fluid flowing in said duct impinge on said diaphragm and are carried downstream along said diaphragm to said inlet means.
Claim 2
Dependent Claim
295 words
An acoustical filtration system comprising: a duct, adapted to receive a flow of a fluid containing suspended particles which are to be filtered from the fluid by said system, said duct comprising at least three substantially planar sound reflecting walls relatively disposed with respect to one another so that sound reflected from one wall to the adjacent wall will in turn be reflected to a subsequent wall thereby recirculating in a first plane substantially perpendicular to the fluid flow path through said duct; sound generating means for producing an oscillatory sonic signal characterized by a relatively high velocity in a first direction for a short portion of the period of said sonic wave and a relatively low velocity in an opposite direction for a relatively long portion of the period of said sonic wave in a predetermined mark-space ratio, said sound generating means disposed with respect to a wall of said duct so as to introduce into a fluid flowing within said duct a sound wave propagating in said first plane; a sound permeable, particle impermeable diaphragm disposed at a point in said duct so as to intersect said first plane, said diaphragm disposed in a second plane substantially parallel with the fluid flow passage through said duct and substantially perpendicular to said propagating sound waves; and inlet means disposed in proximity with a downstream portion of said diaphragm for withdrawing matter flowing along said diaphragm in said duct, said circulating sound waves producing at least a component of velocity in particles flowing within said duct which is transverse to said diaphragm and to the fluid flow path in said duct, whereby particles suspended in fluid flowing in said duct impinge on said diaphragm and are carried downstream along said diaphragm to said inlet means.
Claim 3
Dependent Claim
24 words
A system as in claim 1 wherein said sound generating means produces pressure pulses of mark-space ratio less than one-third but greater than one-fourteenth.
Claim 4
Dependent Claim
77 words
A system as in claim 1 wherein the fluid flows along a path with a ceRtain velocity and wherein the asymmetrical sound wave has a certain velocity of propagation through the fluid, and wherein said sound generating means is oriented with respect to said duct such that the sound wave is propagated through the fluid in a direction providing a propagation velocity component which is equal in magnitude but opposite in polarity to the fluid flow velocity.
Claim 5
Dependent Claim
63 words
A system as in claim 1 wherein the duct comprises four sound reflecting walls, a first wall being concave from within, a second wall being convex from within, the third and fourth walls being planar, said sound generating means and said first and second walls being oriented such that the sound wave reflected from said concave wall is incident upon said convex wall.
Claim 6
Dependent Claim
29 words
A system as in claim 4 wherein said sound generating means is positioned to couple the asymmetrical sound wave to the fluid within the duct adjacent said convex wall.
Claim 7
Dependent Claim
90 words
A system as in claim 1 which further includes means for providing a signal in accord with the velocity of fluid flow through said duct and means responsive to said signal for rotating said sound generating means about an axis orthogonal to that of the duct through an angle which is substantially equal to arc sin v/Vs, where v is the velocity of fluid flow and Vs is the speed of sound in the fluid, and in a direction to produce an upstream component of propagation of the sound wave.
Claim 8
Dependent Claim
56 words
A system as in claim 1 in which the acoustical power coupled into the duct exceeds the acoustical power losses in the duct, the system further including means for providing a signal in accord with the amplitude of recirculated sound pulses and means responsive to said signal for periodically enabling and disabling said sound generating means.
Claim 9
Dependent Claim
40 words
A system as in claim 1 which further includes means for providing a signal in accord with deviations from said predetermined mark-space ratio and means responsive to said signal for controlling the acoustical power output of said sound generating means.
Claim 10
Dependent Claim
66 words
A system as in claim 1 which further includes first transducing means responsive to recirculated sound pulses, second transducing means responsive to sound pulses provided by said sound generating means, means responsive to the first and second transducers for detecting deviations in synchronism between the pulses generated and the pulses recirculated, and means responsive to the detecting means for controlling the frequency of the generating means.
Claim 11
Dependent Claim
35 words
A system as in claim 1 which further includes means for filtering the fluid withdrawn by said inlet means, and outlet means for introducing the filtered fluid into the duct upstream of said reflecting walls.
Claim 12
Dependent Claim
19 words
A system as in claim 10 in which the filtering means comprises a plurality of filters connected in parallel.
Claim 13
Dependent Claim
40 words
A system as in claim 10 wherein said inlet means comprises a pitot inlet slit positioned adjacent the downstream portion of said diaphragm, and said outlet means comprises a venturi outlet slit positioned adjacent the upstream portion of said diaphragm.
Claim 14
Dependent Claim
76 words
An asymmetrical sound wave generator including in combination a wedge-shaped chamber having a throat diaphragm and a conductive mouth plate which is concave from within, a dielectric layer of uniform thickness secured to the interior surface of the mouth plate, a thin layer of conductive material covering the dielectric layer, the chamber containing a gas, and means for applying an alternating voltage of a certain frequency between the mouth plate and the layer of conductive material.
Claim 15
Dependent Claim
76 words
An asymmetrical sound wave generator including in combination a wedge-shaped chamber having a throat diaphragm and a conductive mouth plate which is concave from within, a dielectric layer of uniform thickness secured to the interior surface of the mouth plate, a thin layer of conductive material covering the dielectric layer, the chamber containing a gas, and means for applying an alternating voltage of a certain frequency between the mouth plate and the layer of conductive material.
Claim 16
Dependent Claim
28 words
A generator as in claim 13 wherein the dielectric layer has a thickness which is somewhat less than that providing one-quarter wave length resonance at twice said frequency.
Claim 17
Dependent Claim
27 words
A generator as in claim 13 wherein the dielectric layer has a small bulk modulus of elasticity which is of the order of magnitude of 20,000 p.s.i.
Claim 18
Dependent Claim
22 words
A generator as in claim 13 wherein the mouth plate has a thickness providing one-quarter wave lengtH resonance at twice said frequency.
Claim 19
Dependent Claim
21 words
A generator as in claim 13 wherein the gas has a high molecular weight and a low ratio of specific heats.
Claim 20
Dependent Claim
11 words
A generator as in claim 13 wherein the gas is dichlorotetrafluoroethane.
Claim 21
Dependent Claim
25 words
A generator as in claim 13 wherein said throat diaphragm comprises a convex sound reflector so disposed that the converging sound wave is incident thereon.
Claim 22
Dependent Claim
26 words
A generator as in claim 13 wherein the diaphragm has a small bulk modulus of elasticity which is of the order of magnitude of 20,000 p.s.i.
Claim 23
Dependent Claim
25 words
A generator as in claim 13 wherein the diaphragm comprises a delay line having a thickness which is an integral number of half wave lengths.
Claim 24
Dependent Claim
15 words
A generator as in claim 13 wherein the alternating voltage means provides a sinusoidal voltage.
Claim 25
Dependent Claim
54 words
An asymmetrical sound wave generator according to claim 22 wherein said chamber is of a length affording transmission of the converging sound wave through the gas for a distance sufficient to produce high amplitude pressure pulses of mark-space ratio differing appreciably from unity, and means coupling said pressure pulses to the external fluid medium.
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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) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |