US4183010A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure compensating coaxial line hydrophone and method
Assignee: General Dynamics Government Systems Corp
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Filing: 1977-03-14
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Granted: 1980-01-08
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Expires: 1997-03-14
Abstract
Abstract The utility of a coaxial electret cable transducer as a hydrophone at shallow depths (low hydrostatic pressure) is extended for operation at substantially greater depths (high hydrostatic pressure) by the combination of the electret with a polymer material having piezoelectric properties, i.e., a piezoid. The electret and piezoid are separate flexible materials radially stacked within the cable or alternatively and preferably constitute a single material formed to have both electret and piezoelectric properties. One substance useful as the piezoid or as the electret-piezoid combination is polyvinylidene fluoride (PVF 2 ). The invention also comprehends the method of measuring underwater soundings at either low or high hydrostatic pressures with the aforementioned coaxial cable as an electrostatic transducer by measuring electrical signals generated across the cable conductors when the ambient pressure is low and as a piezoelectric transducer across the conductors when such pressure is high.
Inventors
- 👤 G. Kirby Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:07
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/16; G01V1/20; G01V1/201; G01V1/208; H; H10; H10N; H10N30/00; H10N30/60; Y; Y10; Y10S; Y10S310/00; Y10S310/80
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
104 words
A hydrophone having first and second output terminals and adapted to produce an electrical signal across said terminals in response to application of a mechanical force thereto, said hydrophone comprising a coaxial cable having first conductor means electrically connected to said first terminal and second conductor means electrically connected to said second terminal, said first conductor means comprising outer and inner conductors spaced outwardly and inwardly, respectively, from said second conductor means, and dielectric means comprising an electret disposed between said second conductor means and one of said conductors and a piezoid disposed between said second conductor means and the other of said conductors.
Claim 2
Dependent Claim
104 words
A hydrophone having first and second output terminals and adapted to produce an electrical signal across said terminals in response to application of a mechanical force thereto, said hydrophone comprising a coaxial cable having first conductor means electrically connected to said first terminal and second conductor means electrically connected to said second terminal, said first conductor means comprising outer and inner conductors spaced outwardly and inwardly, respectively, from said second conductor means, and dielectric means comprising an electret disposed between said second conductor means and one of said conductors and a piezoid disposed between said second conductor means and the other of said conductors.
Claim 3
Dependent Claim
34 words
The hydrophone according to claim 1 in which said electret is disposed between said second conductor means and said outer conductor, said piezoid being disposed between said second conductor means and said inner conductor.
Claim 4
Dependent Claim
21 words
The hydrophone according to claim 1 in which said electret comprises tetrafluoroethylene and said piezoid comprises polyvinylidene fluoride (PVF 2 ).
Claim 5
Independent Claim
108 words
The method of detecting mechanical vibrations applied to the exterior of a coaxial cable transducer in high and low ambient pressures, said transducer having at least two radially spaced conductors and dielectric means between the conductors, said dielectric means having electret and piezoelectric properties, consisting of the steps of measuring electrostatically generated signals across said conductors and the dielectric means when the ambient pressure is low, measuring piezoelectrically generated signals across said conductors and dielectric means when said ambient pressure is high, and measuring electrostatically and piezoelectrically generated signals across said conductors and the dielectric means when said ambient pressure is between the high and low value limits.
Claim 6
Independent Claim
108 words
The method of detecting mechanical vibrations applied to the exterior of a coaxial cable transducer in high and low ambient pressures, said transducer having at least two radially spaced conductors and dielectric means between the conductors, said dielectric means having electret and piezoelectric properties, consisting of the steps of measuring electrostatically generated signals across said conductors and the dielectric means when the ambient pressure is low, measuring piezoelectrically generated signals across said conductors and dielectric means when said ambient pressure is high, and measuring electrostatically and piezoelectrically generated signals across said conductors and the dielectric means when said ambient pressure is between the high and low value limits.
Claim 7
Independent Claim
113 words
The method of sensing underwater soundings at small depths in which hydrostatic pressures are low and at large depths in which hydrostatic pressures are high consisting of the steps of forming a coaxial cable transducer with inner and outer conductors and intermediate dielectric filler having both electret and piezoelectric properties, connecting the conductors at one end of the transducer to electrical signal detecting apparatus, immersing said transducer in the water in which the soundings are to be sensed, measuring electrostatically generated signals produced by vibrations of the exterior of said transducer at the small depths and piezoelectrically generated signals at large depths whereby transducer sensitivity to underwater soundings is independent of hydrostatic pressure.
Claim 8
Independent Claim
113 words
The method of sensing underwater soundings at small depths in which hydrostatic pressures are low and at large depths in which hydrostatic pressures are high consisting of the steps of forming a coaxial cable transducer with inner and outer conductors and intermediate dielectric filler having both electret and piezoelectric properties, connecting the conductors at one end of the transducer to electrical signal detecting apparatus, immersing said transducer in the water in which the soundings are to be sensed, measuring electrostatically generated signals produced by vibrations of the exterior of said transducer at the small depths and piezoelectrically generated signals at large depths whereby transducer sensitivity to underwater soundings is independent of hydrostatic pressure.
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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) | 1983-01-07 | 1983-07-09 | 1984-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-07 | 1987-07-09 | 1988-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-07 | 1991-07-09 | 1992-01-08 | $7700.00 | Window Closed / Lapsed |