US3810000A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Earth polarization meter with voltage control during current injection
Assignee: National Research Development Corp UK
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Filing: 1972-02-16
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Granted: 1974-05-07
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Expires: 1992-02-16
Abstract
Abstract This invention concerns a meter for measuring polarisation induced in the earth and in particular for measuring transient voltages that follow the termination of direct current flow through the ground. In this device automatic normalisation of the data is achieved by correllating the voltage source producing the transient voltages with the potential measured across measurement electrodes in such a manner that the voltage source and measurement circuits are not otherwise electrically linked.
Inventors
- 👤 A Aspinall
- 👤 D Spruce
- 👤 J Lynam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:45
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/02; G01V3/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
140 words
An earth polarization meter comprising: first and second pairs of earth electrodes, a source of electric power for connection to said first pair of earth electrodes, measuring circuit means for connection to said second pair of electrodes for measuring the potential difference between the earth self potential before injection of current into the earth by said source and the earth polarization voltage between said electrodes of said second pair produced following injection of current from said source into the earth and after said source ceases injecting current into the earth, and control means coupled to said second pair of electrodes and operative during injection of current into the earth for controlling the voltage produced by said source to maintain the potential difference between said electrodes of second pair of electrodes constant while said source is injecting current into the earth.
Claim 2
Dependent Claim
140 words
An earth polarization meter comprising: first and second pairs of earth electrodes, a source of electric power for connection to said first pair of earth electrodes, measuring circuit means for connection to said second pair of electrodes for measuring the potential difference between the earth self potential before injection of current into the earth by said source and the earth polarization voltage between said electrodes of said second pair produced following injection of current from said source into the earth and after said source ceases injecting current into the earth, and control means coupled to said second pair of electrodes and operative during injection of current into the earth for controlling the voltage produced by said source to maintain the potential difference between said electrodes of second pair of electrodes constant while said source is injecting current into the earth.
Claim 3
Dependent Claim
83 words
An earth polarization meter as claimed in claim 1 further including means for detecting the potential between said second pair of electrodes and wherein said control means comprise a light source the intensity of which is controlled by the potential between said electrodes of said second pair as detected by said detecting means and a photo sensitive means mounted for receiving illumination from said light source for varying the voltage supplied by the source of electric power as a function of incident light.
Claim 4
Dependent Claim
48 words
An earth polarisation meter as claimed in claim 2 wherein the source of electric power comprises a current switch for connection to said first pair of earth electrodes and controlled by a multi-vibrator, the current switch being coupled to a voltage stabliser which includes said photo sensitive means.
Claim 5
Dependent Claim
49 words
An earth polarization meter as claimed in claim 3 wherein the detecting means and measuring circuit means each comprise a connected FET amplifier, and further including a back off device connected to the junction between the FET amplifiers and arranged for connection to said second pair of earth electrodes.
Claim 6
Dependent Claim
37 words
An earth polarisation meter as claimed in claim 4 wherein the output of the multi-vibrator is connected via at least one delay circuit to a switch connecting the output of the FET amplifiers to a difference integrator.
References Cited (Backward Citations)
US2611004A
Cited
US2880389A
Cited
US2931972A
Cited
US3054046A
Cited
US3235793A
Cited
US3283240A
Cited
US3566233A
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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) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |