US4941135A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic field generating device
Assignee: BTG International Ltd
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Filing: 1989-05-08
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Granted: 1990-07-10
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Expires: 2009-05-08
Abstract
Abstract A liquid column (2) is placed between two high-frequency ultrasound sources (6) in the field of a standing wave produced by the sources. Each source produces a convergent beam that compensates for a substantial part of the attenuation of the ultrasound energy that occurs at higher frequencies. It is thereby possible to increase considerably the axial distance along the standing wave over which streaming effects due to acoustic pressure are absent or negligible. It is also possible to increase the angle of convergence to compensate for divergence of the outputs from the sources.
Inventors
- 👤 Cornelius J. Schram
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:25
CPC Classifications
G; G10; G10K; G10K15/00; G10K11/00; G10K11/18; G10K11/26
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
118 words
A method of generating an ultrasonic energy field in an enclosed space filled with a fluid medium, comprising the steps of: disposing an ultrasonic energy source at a spacing from said enclosed space; directing a converging ultrasonic energy beam from said source along an axis of propagation extending through said enclosed space; and converging said beam from the source through the fluid medium at an angle sufficiently great such that the beam has a cross-sectional area throughout the enclosed space to at least substantially compensate for attenuation of ultrasonic energy in the fluid medium through at least substantially the whole of said enclosed space such that a substantially uniform energy density is created in the said enclosed space.
Claim 2
Independent Claim
118 words
A method of generating an ultrasonic energy field in an enclosed space filled with a fluid medium, comprising the steps of: disposing an ultrasonic energy source at a spacing from said enclosed space; directing a converging ultrasonic energy beam from said source along an axis of propagation extending through said enclosed space; and converging said beam from the source through the fluid medium at an angle sufficiently great such that the beam has a cross-sectional area throughout the enclosed space to at least substantially compensate for attenuation of ultrasonic energy in the fluid medium through at least substantially the whole of said enclosed space such that a substantially uniform energy density is created in the said enclosed space.
Claim 3
Dependent Claim
24 words
A method according to claim 1 wherein the ultrasonic energy output from the source is in the MHz range, up to about 25 MHz.
Claim 4
Dependent Claim
22 words
A method according to claim 1 wherein the beam is given an additional convergence to compensate for divergence of the source output.
Claim 5
Dependent Claim
21 words
A method according to claim 1 wherein a standing wave is formed in the ultrasonic field created by the source output.
Claim 6
Dependent Claim
21 words
Apparatus according to claim 9 wherein the output from said source is in the MHz range, up to about 25 MHz.
Claim 7
Dependent Claim
18 words
Apparatus according to claim 9 wherein the acoustic energy source has a concave emitting surface producing said convergence.
Claim 8
Dependent Claim
21 words
Apparatus according to claim 9 wherein lens means is placed in front of the acoustic energy source to produce said convergence.
Claim 9
Dependent Claim
32 words
Apparatus according to claim 9 further comprising a pair of sources producing a standing wave by interference of their fields in a region in which the attenuation of both sources is compensated.
Claim 10
Dependent Claim
142 words
Apparatus for generating an acoustic energy field in a volume of fluid, comprising: an acoustic energy source for outputting a convergent acoustic energy beam along an axis of propagation; a container for said volume of fluid, said container being spaced from said source along said axis of propagation such that the beam from said source generates the acoustic energy field in said container; and means for converging the beam from said source so as to form a convergent beam having an angle of convergence sufficiently great to at least substantially compensate for attenuation of acoustic energy along the axis of propagation of said beam, said convergent beam occupying and creating a substantially uniform energy density over the entire cross-section of said container in the direction of the axis of propagation over at least a substantial part of the length of said container.
Claim 11
Dependent Claim
142 words
Apparatus for generating an acoustic energy field in a volume of fluid, comprising: an acoustic energy source for outputting a convergent acoustic energy beam along an axis of propagation; a container for said volume of fluid, said container being spaced from said source along said axis of propagation such that the beam from said source generates the acoustic energy field in said container; and means for converging the beam from said source so as to form a convergent beam having an angle of convergence sufficiently great to at least substantially compensate for attenuation of acoustic energy along the axis of propagation of said beam, said convergent beam occupying and creating a substantially uniform energy density over the entire cross-section of said container in the direction of the axis of propagation over at least a substantial part of the length of said container.
Claim 12
Independent Claim
121 words
A method of rendering more uniform the energy density of an ultrasonic standing wave in a fluid medium contained in an enclosed space, comprising the steps of: disposing respective ultrasonic sources at a distance from said enclosed space; and propagating from said sources converging ultrasonic energy beams that intersect within said enclosed space to form the standing wave, said beams being given an angle of convergence sufficiently great to at least substantially compensate for attenuation of ultrasonic energy in the fluid medium, whereby the standing wave over at least a substantial part of the length of the enclosed space has a substantially uniform energy density over the entire cross-section of said enclosed space in a direction transverse to the standing wave.
Claim 13
Independent Claim
121 words
A method of rendering more uniform the energy density of an ultrasonic standing wave in a fluid medium contained in an enclosed space, comprising the steps of: disposing respective ultrasonic sources at a distance from said enclosed space; and propagating from said sources converging ultrasonic energy beams that intersect within said enclosed space to form the standing wave, said beams being given an angle of convergence sufficiently great to at least substantially compensate for attenuation of ultrasonic energy in the fluid medium, whereby the standing wave over at least a substantial part of the length of the enclosed space has a substantially uniform energy density over the entire cross-section of said enclosed space in a direction transverse to the standing wave.
Claim 14
Dependent Claim
24 words
A method according to claim 10, wherein the ultrasonic energy outputs from the sources are in the MHz range, up to about 25 MHz.
Claim 15
Dependent Claim
24 words
A method according to claim 10, wherein the beams are given an additional convergence to compensate for divergence of the outputs of the sources.
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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) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-09 | 2002-01-08 | 2002-07-10 | $7700.00 | Window Closed / Lapsed |