Patent US3826976A successfully refreshed from Google Patents.
US3826976A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Calibration apparatus and method for an eddy current phase sensitive selector
Assignee: Jones and Laughlin Steel Inc
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Filing: 1972-12-07
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Granted: 1974-07-30
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Expires: 1992-12-07
Abstract
Abstract Electromagnetic inspection apparatus, such as a phase sensitive eddy current inspection device, is calibrated by providing voltage pulses of selected amplitude to a calibration coil or solenoid located in fixed proximity to the inspection apparatus test coil or solenoid, creating defect-simulating magnetic disturbances which are sensed by the test coil.
Inventors
- 👤 J Winston
- 👤 W Greer
- 👤 M Steele
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:01
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/90; G01N27/9073; G01N27/9086
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
116 words
In combination with a phase sensitive electro magnetic inspection apparatus, including a test coil, a high frequency oscillator connected to said test coil, a discriminator responsive to said test coil, phase analysis circuitry and a sensitivity control means, a calibration apparatus, comprising: a calibration coil electro magnetically coupled to said test coil; pulse generating means electrically connected to said calibration coil for generating calibration pulses of controlled frequency and phase; digital divider means electrically connected to said test coil and responsive to said high frequency oscillator for synchronizing the phase of said calibration pulses; and means electrically connected to said calibration coil and said pulse generating means for selectively varying the amplitude of said calibration pulses.
Claim 2
Dependent Claim
116 words
In combination with a phase sensitive electro magnetic inspection apparatus, including a test coil, a high frequency oscillator connected to said test coil, a discriminator responsive to said test coil, phase analysis circuitry and a sensitivity control means, a calibration apparatus, comprising: a calibration coil electro magnetically coupled to said test coil; pulse generating means electrically connected to said calibration coil for generating calibration pulses of controlled frequency and phase; digital divider means electrically connected to said test coil and responsive to said high frequency oscillator for synchronizing the phase of said calibration pulses; and means electrically connected to said calibration coil and said pulse generating means for selectively varying the amplitude of said calibration pulses.
Claim 3
Independent Claim
124 words
A method for calibrating a phase sensitive eddy current inspection device having a test coil and high frequency oscillator, including the steps of: electro magnetically coupling said test coil to a calibration coil; supplying calibration pulses of controlled frequency and phase to said calibration coil to develope a magnetic disturbance in said test coil and a resulting output signal from the inspection device indicitive of the amplitude and phase of the magnetic disturbance; phase synchronizing said calibration pulses to the output of said high frequency oscillator; adjusting the amplitude of the calibration pulses to a preselected level to vary the amplitude of the magnetic disturbance and the resulting electrical output signal; and thereafter adjusting the amplitude of the output signal to a preselected level.
Claim 4
Independent Claim
124 words
A method for calibrating a phase sensitive eddy current inspection device having a test coil and high frequency oscillator, including the steps of: electro magnetically coupling said test coil to a calibration coil; supplying calibration pulses of controlled frequency and phase to said calibration coil to develope a magnetic disturbance in said test coil and a resulting output signal from the inspection device indicitive of the amplitude and phase of the magnetic disturbance; phase synchronizing said calibration pulses to the output of said high frequency oscillator; adjusting the amplitude of the calibration pulses to a preselected level to vary the amplitude of the magnetic disturbance and the resulting electrical output signal; and thereafter adjusting the amplitude of the output signal to a preselected level.
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) | 1977-07-29 | 1978-01-28 | 1978-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-29 | 1982-01-28 | 1982-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-29 | 1986-01-28 | 1986-07-30 | $7700.00 | Window Closed / Lapsed |