Patent US3577071A successfully refreshed from Google Patents.
US3577071A
Expired / Lapsed
US
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Microwave material tester
Assignee: STAVELEY INSTRUMENTS Inc 421 NORTH QUAY STREET KENNEWICK WA 99336 A CORP OF WA
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Filing: 1969-01-06
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Granted: 1971-05-04
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Expires: 1989-01-06
Abstract
Abstract A nondestructive testing device is described wherein a workpiece is coupled to a microwave resonant cavity. In addition to the sampling cavity, a tuneable reference resonant cavity may be employed. A modulated tuneable klystron energizes both resonant cavities. A first phase-sensitive amplifier, responsive to the test cavity, controls a servosystem tuning the reference resonant cavity while a second phase-sensitive amplifier responsive to the reference resonant cavity tunes the klystron so that both cavities and the klystron are tuned alike after coupling of the workpiece. A digital readout is provided to indicate the tuning of the reference cavity. Alternatively, a single resonant cavity is coupled to a swept frequency klystron, with a filamentary workpiece passed through the cavity. The resultant Q of the cavity, and changes in resonant frequency thereof are indicated by an oscilloscope display.
Inventors
- 👤 Jack T Collins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:16
CPC Classifications
G; G01; G01N; G01N22/00; G01R; G01R27/00; G01R27/28; G01R27/32
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
303 words
A nondestructive material tester for testing surface conditions of a workpiece; a first microwave cavity resonator having one opening thereon which is adapted to be coupled to one surface of the workpiece to close the cavity of said resonator whereby the resonant frequency of said resonator is altered by the surface condition of the workpiece; a second microwave cavity resonator being permanently sealed and including adjusting means mounted therein to change the resonant frequency of said second resonator; a signal generator for generating a signal at a reference frequency; a source of energy in the microwave frequency, said source being coupled to be responsive to said signal generator and having an output coupled to simultaneously supply microwave energy to said first and said second resonator to cause said resonators to resonate, said source including adjusting means to change the frequency of the energy thereof; a first phase-sensitive means being coupled to be responsive to energy from said first resonator and said siGnal generator and having an output for providing an error signal therebetween; a second phase-sensitive means being coupled to be responsive to energy from said second resonator and said signal generator and having an output for providing an error signal of the energy therebetween, the output of said second phase-sensitive means being coupled to the adjusting means of said source for maintaining said source in tune with said second resonator; servo means responsive to the error signal output of said first phase-sensitive means and being coupled to the adjusting means of said second resonator for maintaining said first resonator in tune with said second resonator; and readout means coupled to be responsive to the changes in frequency of the energy in said second resonator for providing an indication of the surface condition of the workpiece as determined by the changes in frequency.
Claim 2
Dependent Claim
303 words
A nondestructive material tester for testing surface conditions of a workpiece; a first microwave cavity resonator having one opening thereon which is adapted to be coupled to one surface of the workpiece to close the cavity of said resonator whereby the resonant frequency of said resonator is altered by the surface condition of the workpiece; a second microwave cavity resonator being permanently sealed and including adjusting means mounted therein to change the resonant frequency of said second resonator; a signal generator for generating a signal at a reference frequency; a source of energy in the microwave frequency, said source being coupled to be responsive to said signal generator and having an output coupled to simultaneously supply microwave energy to said first and said second resonator to cause said resonators to resonate, said source including adjusting means to change the frequency of the energy thereof; a first phase-sensitive means being coupled to be responsive to energy from said first resonator and said siGnal generator and having an output for providing an error signal therebetween; a second phase-sensitive means being coupled to be responsive to energy from said second resonator and said signal generator and having an output for providing an error signal of the energy therebetween, the output of said second phase-sensitive means being coupled to the adjusting means of said source for maintaining said source in tune with said second resonator; servo means responsive to the error signal output of said first phase-sensitive means and being coupled to the adjusting means of said second resonator for maintaining said first resonator in tune with said second resonator; and readout means coupled to be responsive to the changes in frequency of the energy in said second resonator for providing an indication of the surface condition of the workpiece as determined by the changes in frequency.
Claim 3
Dependent Claim
18 words
In the nondestructive material tester as defined in claim 1 wherein said source of energy being a klystron.
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) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |