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US4583207A
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Magnetohydrodynamic geophone
Assignee: EPLEY MICHAEL G TRUSTEE
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Filing: 1982-11-29
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Granted: 1986-04-15
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Expires: 2002-11-29
Abstract
Abstract A magnetohydrodynamic geophone for seismological detection. The geophone is of rigid shock resistant design, including a sealed, rigid generally conically shaped housing which is adapted to be firmly embedded within the ground in bedrock or the like, in or adjacent to an area to be seismologically monitored. The shock resistant housing includes an isolated interior for receiving an MHD sensor which detects the seismological vibration. The sensor includes a generally tubular conduit containing an electrically conductive fluid, preferably mercury or an electrolyte. A very strong magnetic field is set up perpendicularly with respect to the plane occupied by the conduit. An electric field is generated through the Faraday Effect in response to vibrations. Preferably the conduit is of ring shaped configuration, and the conductive fluid is continuously circulated throughout it. A steady state operating point is thus established, and perturbations established by vibration are detected by associated high gain amplification circuitry which processes the electric field signals sensed by electrodes attached to the conduit. The electrodes are attached to the conduit and oriented generally perpendicular with respect to the magnetic field.
Inventors
- 👤 Sedley J. Greer, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:27
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/16; G01V1/18; G01V1/181; G01H; G01H11/00; G01H11/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
121 words
A geophone comprising: a rigid, shock resistant housing having a sealed interior, the housing adapted to be firmly embedded within the ground in an area to be seismologically monitored; a magnetohydrodynamic seismological sensor disposed within said housing for detecting seismological waves, said sensor comprising: a generally tubular conduit containing an electrically conductive fluid, said conduit occupying a plane; magnetic means for establishing a magnetic field generally perpendicular to said plane of said conduit; and, means for sensing perturbations in the electric field normal to said magnetic field for monitoring seismic disturbances, said last mentioned means comprising: electrode means oriented transversely with respect to said magnetic field for sensing said electrical field; and, high gain amplifier means for greatly amplifying said perturbations.
Claim 2
Dependent Claim
121 words
A geophone comprising: a rigid, shock resistant housing having a sealed interior, the housing adapted to be firmly embedded within the ground in an area to be seismologically monitored; a magnetohydrodynamic seismological sensor disposed within said housing for detecting seismological waves, said sensor comprising: a generally tubular conduit containing an electrically conductive fluid, said conduit occupying a plane; magnetic means for establishing a magnetic field generally perpendicular to said plane of said conduit; and, means for sensing perturbations in the electric field normal to said magnetic field for monitoring seismic disturbances, said last mentioned means comprising: electrode means oriented transversely with respect to said magnetic field for sensing said electrical field; and, high gain amplifier means for greatly amplifying said perturbations.
Claim 3
Dependent Claim
33 words
The geophone as defined in claim 1 including analog-to-digital converter means for digitizing the perturbation signal derived from said electrode means and digital transmitter means for radioing said signal to a remote location.
Claim 4
Dependent Claim
18 words
The geophone as defined in claim 2 wherein said tubular conduit is in the form of a ring.
Claim 5
Dependent Claim
18 words
The geophone as defined in claim 3 including mechanical pump means for continuously circulating fluid throughout said conduit.
Claim 6
Dependent Claim
31 words
The geophone as defined in claim 4 wherein half of said ring is of a first known diameter and the other half of said ring is of a smaller known diameter.
Claim 7
Dependent Claim
15 words
The geophone as defined in claim 4 wherein said pump means comprises a mechanical turbine.
Claim 8
Dependent Claim
100 words
An MHD geophone comprising: a rigid, shock resistant housing having a sealed interior, the housing adapted to be firmly embedded within the ground in an area to be seismologically monitored; a magnetohydrodynamic seismological sensor disposed within said housing for detecting seismological waves, said sensor comprising: a generally tubular conduit containing an electrically conductive fluid, said conduit being in the form of a ring and occupying a plane; magnetic means for establishing a magnetic field generally perpendicular to said plane of said conduit; and, means for sensing perturbations in the electric field normal to said magnetic field for monitoring seismic disturbances.
Claim 9
Dependent Claim
100 words
An MHD geophone comprising: a rigid, shock resistant housing having a sealed interior, the housing adapted to be firmly embedded within the ground in an area to be seismologically monitored; a magnetohydrodynamic seismological sensor disposed within said housing for detecting seismological waves, said sensor comprising: a generally tubular conduit containing an electrically conductive fluid, said conduit being in the form of a ring and occupying a plane; magnetic means for establishing a magnetic field generally perpendicular to said plane of said conduit; and, means for sensing perturbations in the electric field normal to said magnetic field for monitoring seismic disturbances.
Claim 10
Dependent Claim
18 words
The geophone as defined in claim 7 including mechanical pump means for continuously circulating fluid throughout said conduit.
Claim 11
Dependent Claim
31 words
The geophone as defined in claim 8 wherein half of said ring is of a first known diameter and the other half of said ring is of a smaller known diameter.
Claim 12
Dependent Claim
24 words
The geophone as defined in claim 8 wherein said pump means comprises means for establishing a reverse magnetohydrodynamic effect associated with said conduit means.
Claim 13
Dependent Claim
24 words
The geophone as defined in claim 10 including means for continuously vibrating said electrically conductive fluid, said last mentioned means comprising piezoelectric oscillation means.
Claim 14
Dependent Claim
107 words
A geophone comprising: a rigid, shock resistant housing having a sealed interior, the housing adapted to be firmly embedded within the ground in an area to be seismologically monitored; a magnetohydrodynamic seismological sensor disposed within said housing for detecting seismological waves, said sensor comprising: a generally tubular conduit containing an electrically conductive fluid, said conduit occupying a plane; magnetic means for establishing a magnetic field generally perpendicular to said plane of said conduit; means for sensing perturbances in the electric field normal to said magnetic field for monitoring seismic disturbances; and, means for continuously vibrating said electrically conductive fluid, said last mentioned means comprising piezoelectric oscillation means.
Claim 15
Dependent Claim
107 words
A geophone comprising: a rigid, shock resistant housing having a sealed interior, the housing adapted to be firmly embedded within the ground in an area to be seismologically monitored; a magnetohydrodynamic seismological sensor disposed within said housing for detecting seismological waves, said sensor comprising: a generally tubular conduit containing an electrically conductive fluid, said conduit occupying a plane; magnetic means for establishing a magnetic field generally perpendicular to said plane of said conduit; means for sensing perturbances in the electric field normal to said magnetic field for monitoring seismic disturbances; and, means for continuously vibrating said electrically conductive fluid, said last mentioned means comprising piezoelectric oscillation means.
Claim 16
Dependent Claim
35 words
The geophone as defined in claim 12 wherein said sensor includes: electrode means oriented transversely with respect to said magnetic field for sensing electrical field; and, high gain amplifier means for greatly amplifying said perturbations.
Claim 17
Dependent Claim
31 words
The geophone as defined in claim 13 wherein half of said ring is of a first known diameter and the other half of said ring is of a smaller known diameter.
References Cited (Backward Citations)
US3930218A
Cited
US4419895A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |