Patent US4423768A successfully refreshed from Google Patents.
US4423768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezoelectric polymer heat exchanger
Assignee: United States Department of the Army
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Filing: 1982-04-20
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Granted: 1984-01-03
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Expires: 2002-04-20
Abstract
Abstract Disclosed is apparatus for providing for increased heat transfer efficiencyf a heat exchanger by separating contiguous fluid conductive channels by means of a flexible sheet fabricated from a piezoelectric polymer. An electrode pattern of predetermined configuration is applied to one or both sides of the piezoelectric sheet and an electrical signal applied thereto in order to set the sheet into a flexual resonance condition whereupon a standing wave pattern is established to not only break up the boundary layer of fluid which adheres to each side of the sheet, but also minimizing the thickness of the laminar sub-layer.
Inventors
- 👤 Seymour Edelman
- 👤 Lowell D. Ballard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:32
CPC Classifications
F; F28; F28F; F28F13/00; F28F13/02; F28F13/16; Y; Y10; Y10S; Y10S310/00; Y10S310/80
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
200 words
A heat exchanger comprising: at least one hollow cylindrical structure comprising two fluid conductive channels through which respective relatively warm and cold fluids are led for exchanging appreciable amounts of heat therebetween; the said fluid conductive channels being completely separated, being formed in said cylindrical structure by presence of a tubular, heat conductive partition means, one channel being within, and one channel surrounding said tubular means, within said cylindrical structure, said heat conductive partition means comprising piezoelectric polymer material; first and second helical type electrode means formed in a double helix directly on the said tubular partition means, on the same side of said partition, electrically coupled at one of the electrode means mutually same ends, and wound screw thread about said tubular means, connected to an alternating current electrical signal piezoelectrically driving said partition means to periodically undulate; and a signal source for the said alternating current signal being provided for delivering a signal at a particular frequency equal to the natural frequency of resonance of transverse vibration of the said partition piezoelectric material so as to generate a standing wave pattern therein, the resonance factor enhancing the heat flow action across said partition compared to non resonant undulation.
Claim 2
Dependent Claim
200 words
A heat exchanger comprising: at least one hollow cylindrical structure comprising two fluid conductive channels through which respective relatively warm and cold fluids are led for exchanging appreciable amounts of heat therebetween; the said fluid conductive channels being completely separated, being formed in said cylindrical structure by presence of a tubular, heat conductive partition means, one channel being within, and one channel surrounding said tubular means, within said cylindrical structure, said heat conductive partition means comprising piezoelectric polymer material; first and second helical type electrode means formed in a double helix directly on the said tubular partition means, on the same side of said partition, electrically coupled at one of the electrode means mutually same ends, and wound screw thread about said tubular means, connected to an alternating current electrical signal piezoelectrically driving said partition means to periodically undulate; and a signal source for the said alternating current signal being provided for delivering a signal at a particular frequency equal to the natural frequency of resonance of transverse vibration of the said partition piezoelectric material so as to generate a standing wave pattern therein, the resonance factor enhancing the heat flow action across said partition compared to non resonant undulation.
Claim 3
Dependent Claim
166 words
A heat exchanger comprising: at least one hollow cylindrical structure comprising two fluid conductive channels through which respective relatively warm and cold fluids are led for exchanging appreciable amounts of heat therebetween; the said fluid conductive channels being completely separated being formed in said cylindrical structure by presence of a tubular, heat conductive partition means, said heat conductive partition means comprising piezoelectric polymer material; first and second helical type electrode means formed on the same side of said tubular partition means coupled at one end, and wound screw thread about said tubular means, connected to an alternating current electrical signal piezoelectrically driving said partition means to periodically undulate; and a signal source for the said alternating current signal being provided for delivering a signal at a particular frequency equal to the natural frequency of resonance of transverse vibration of the said partition so as to generate a standing wave pattern therein, the resonance factor enhancing the heat flow action across said partition compared to non-resonant undulation.
Claim 4
Dependent Claim
166 words
A heat exchanger comprising: at least one hollow cylindrical structure comprising two fluid conductive channels through which respective relatively warm and cold fluids are led for exchanging appreciable amounts of heat therebetween; the said fluid conductive channels being completely separated being formed in said cylindrical structure by presence of a tubular, heat conductive partition means, said heat conductive partition means comprising piezoelectric polymer material; first and second helical type electrode means formed on the same side of said tubular partition means coupled at one end, and wound screw thread about said tubular means, connected to an alternating current electrical signal piezoelectrically driving said partition means to periodically undulate; and a signal source for the said alternating current signal being provided for delivering a signal at a particular frequency equal to the natural frequency of resonance of transverse vibration of the said partition so as to generate a standing wave pattern therein, the resonance factor enhancing the heat flow action across said partition compared to non-resonant undulation.
Claim 5
Dependent Claim
16 words
The heat exchanger of claim 2 wherein said electrode means are formed in a double helix.
Claim 6
Dependent Claim
21 words
The heat exchanger of claim 3 wherein said electrode means are both electrically coupled at one of their mutually same ends.
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) | 1987-01-02 | 1987-07-04 | 1988-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-02 | 1991-07-04 | 1992-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-02 | 1995-07-04 | 1996-01-03 | $7700.00 | Window Closed / Lapsed |