US3757288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cavitation detector
Assignee: Government of France
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Filing: 1971-07-16
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Granted: 1973-09-04
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Expires: 1991-07-16
Abstract
Abstract To distinguish between cavitation and ambient noise, signals are passed to parallel integrator circuits having different time constants which circuits respectively integrate the ambient noise portion alone or in combination with the cavitation portion, the resulting signals being subtracted to obtain an indication of the presence of cavitation.
Inventors
- 👤 J Morin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:08
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/44; G01N29/4409; G01N29/4436; G01H; G01H3/00; G01N29/02; G01N29/032; G01N29/36; G01N29/42; G01N29/48; G01N2291/00; G01N2291/02; G01N2291/024; G01N2291/02433; G01N2291/10; G01N2291/101; Y; Y10; Y10S; Y10S367/00; Y10S367/901
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
133 words
Apparatus for detecting, in a liquid medium, cavitation in the presence of ambient noise which tends to obscure the same, said apparatus comprising means to transduce ambient noise and cavitation produced incidental to rotation of the propeller of a ship into an electrical signal, first and second parallel integrator means to receive said signal and having different time constants such that the integrator means are adapted respectively for integrating the ambient noise alone and the ambient noise with the cavitation to provide two output voltages, means to compare said voltages to determine the presence of cavitation, and a filter between the first said means and integrator means and having a band-pass range of from 1 to 20 kilohertz, the said time constants being about one hundreth and one thousandth of a second respectively.
Claim 2
Dependent Claim
133 words
Apparatus for detecting, in a liquid medium, cavitation in the presence of ambient noise which tends to obscure the same, said apparatus comprising means to transduce ambient noise and cavitation produced incidental to rotation of the propeller of a ship into an electrical signal, first and second parallel integrator means to receive said signal and having different time constants such that the integrator means are adapted respectively for integrating the ambient noise alone and the ambient noise with the cavitation to provide two output voltages, means to compare said voltages to determine the presence of cavitation, and a filter between the first said means and integrator means and having a band-pass range of from 1 to 20 kilohertz, the said time constants being about one hundreth and one thousandth of a second respectively.
Claim 3
Dependent Claim
17 words
Apparatus as claimed in claim 1 wherein said means to compare said voltages includes a subtraction circuit.
Claim 4
Dependent Claim
17 words
Apparatus as claimed in claim 1 comprising indicator means coupled to said means to compare said voltages.
Claim 5
Dependent Claim
12 words
Apparatus as claimed in claim 3 wherein the indicator means include triggers.
Claim 6
Dependent Claim
17 words
Apparatus as claimed in claim 1 wherein said means to cOmpare said voltages with a reference voltage.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |