Patent US3835371A successfully refreshed from Google Patents.
US3835371A
Expired / Lapsed
US
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Apparatus for detecting the presence of electrically conductive material within a given sensing area
Assignee: Individual
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Filing: 1972-07-27
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Granted: 1974-09-10
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Expires: 1992-07-27
Abstract
Abstract A transmitter having a tuned LC circuit which is driven at resonant frequency by alternating current supplied by a digital, square wave pulse circuit is employed with a detector provided by a second tuned LC circuit which is resonant at the transmitter frequency. The winding axis of the detector coil is perpendicular to the winding axis of the transmitter inductance coil. The detector produces an output signal at the transmitter frequency when electrically conductive materials alter the mutual inductance between the coils in the two circuits. The detected signal is amplified and filtered by active, passive and synchronous filtering means and the resulting signal is transmitted to a remote location for analysis. When employed to detect the presence and location of underwater materials, the transmitter circuit and the amplifying and filtering circuits are included in a submerged probe which is connected to a surface vessel by a cable. The connecting cable preferably carries only direct current to reduce noise and eliminate the effect of cable length on proper circuit operation.
Inventors
- 👤 M Mirdadian
- 👤 R Schwartz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:52
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/08; G01V3/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
212 words
Apparatus for detecting the presence of electrically conductive or magnetic flux disturbing means within a given sensing area comprising: a. mounting means including a submergible probe means; b. signal forming means carried by said mounting means; c. transmitting means connected with said signal forming means and carried by said mounting means for forming an energy distribution pattern in said sensing area; d. detecting means carried by said mounting means for forming a detector signal indicating a change in said energy distribution pattern caused by the presence of electrically conductive or magnetic flux disturbing means in said sensing area; e. treating means carried by said mounting means and connected with said detector means for amplifying and filtering said detector signal; f. electrical output conductor means extending from said mounting means to a remote location for conveying said amplified and filtered detector signal to receiving means at said remote location; g. verification means included in said probe means and operable from said remote location for communicating a known signal to said detecting means for verifying proper operation of said apparatus; and h. supply line means extending between said probe means and a source of remotely located, direct current voltage for supplying direct current voltage to power said signal forming means and said detecting means.
Claim 2
Dependent Claim
212 words
Apparatus for detecting the presence of electrically conductive or magnetic flux disturbing means within a given sensing area comprising: a. mounting means including a submergible probe means; b. signal forming means carried by said mounting means; c. transmitting means connected with said signal forming means and carried by said mounting means for forming an energy distribution pattern in said sensing area; d. detecting means carried by said mounting means for forming a detector signal indicating a change in said energy distribution pattern caused by the presence of electrically conductive or magnetic flux disturbing means in said sensing area; e. treating means carried by said mounting means and connected with said detector means for amplifying and filtering said detector signal; f. electrical output conductor means extending from said mounting means to a remote location for conveying said amplified and filtered detector signal to receiving means at said remote location; g. verification means included in said probe means and operable from said remote location for communicating a known signal to said detecting means for verifying proper operation of said apparatus; and h. supply line means extending between said probe means and a source of remotely located, direct current voltage for supplying direct current voltage to power said signal forming means and said detecting means.
Claim 3
Dependent Claim
82 words
Apparatus as defined in claim 1 wherein: a. said transmitting means includes oscillator coil means for radiating electromagnetic energy to form said energy distribution pattern; b. said signal forming means includes oscillator circuit means for controlling the flow of electrical current in said oscillator coil means; and c. said detector Means includes receiving coil means inductively coupled with said oscillator coil means in an amount dependent upon the characteristics of electrically conductive or magnetic flux disturbing means present in said sensing area.
Claim 4
Dependent Claim
44 words
Apparatus as defined in claim 2 wherein said oscillator coil means includes one or more inductive windings having a winding axis which is disposed at a right angle to the winding axis of one or more inductive windings included in said detector coil means.
Claim 5
Dependent Claim
47 words
Apparatus as defined in claim 2 wherein: a. said treating means includes integrated circuit means; and b. a DC to DC converter means is contained in said probe means for converting direct current supplied by said supply line means to direct current for supplying said treating means.
Claim 6
Dependent Claim
37 words
Apparatus as defined in claim 4 wherein said DC to DC converter means includes oscillating means producing time variant signals at a frequency which is different from the frequency of the signals radiated by said transmitter means.
Claim 7
Dependent Claim
60 words
Apparatus as defined in claim 2 further including: a. control line means extending between said remote location and said probe means for supplying direct current control signals to said treating means in said probe means; and b. means included in said probe means and responsive to said control signals for changing the gain of amplifying means in said treating means.
Claim 8
Dependent Claim
138 words
Apparatus as defined in claim 2 wherein: a. said treating means includes: i. synchronous detector means for filtering said detector signal; ii. phase shifting means for shifting the phase of the detector signal relative to the phase of a gate signal employed to control operation of said synchronous detector means whereby the detector signal is input to said synchronous means with a fixed phase relationship relative to said gate signal; b. said gate signal frequency is the same as that of the transmitted signal; and c. the detector signal input to said synchronous detector means is in phase with said gate signal whereby said synchronous detector means conducts only those parts of the detector signal which are in phase with and have the same frequency as the transmitted signal to thereby filter undesired noise from said detector signal.
Claim 9
Dependent Claim
69 words
Apparatus as defined in claim 2 further including: a. digital pulse means in said oscillator circuit means for forming two trains of precisely spaced, square wave pulses having constant pulse widths to produce a symmetrical waveform in the signal emitted by said oscillator coil means; and b. means for adjusting the pulse widths of the pulses in one train relative to those of the pulses in the other train.
Claim 10
Dependent Claim
65 words
Apparatus as defined in claim 2 further including: a. a plurality of contiguous zones in said sensing area; b. transmitting means and detecting means associated with each of said zones for detecting the presence of said electrically conductive or magnetic flux disturbing means in said zones; and c. indicating means for indicating which zone or zones contain said electrically conductive or magnetic flux disturbing means.
Claim 11
Dependent Claim
61 words
Apparatus as defined in claim 2 further including: a. first output means at said remote location connected with said output conductor means and responsive to a relatively low level signal on said conductor means; and b. second output means at said remote location connected with said output conductor means and responsive to a relatively high level signal on said conductor means.
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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) | 1977-09-09 | 1978-03-11 | 1978-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-09 | 1982-03-11 | 1982-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-09 | 1986-03-11 | 1986-09-10 | $7700.00 | Window Closed / Lapsed |