US4624140A
Expired / Lapsed
US
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Liquid medium capacitive displacement sensor
Assignee: OPTIMA SENSOR SYSTEMS Inc
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Filing: 1984-07-30
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Granted: 1986-11-25
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Expires: 2004-07-30
Abstract
Abstract The inside surface of a conductive vessel (preferably spherical) with insulated adjacent segments is coated with a dielectric layer. The vessel is then partly filled with a conductive liquid-like material such as mercury having an upper surface which remains approximately horizontal irrespective of the inclination of the vessel. The capacitance between the segments and liquid varies as a function of the vessel's inclination. Vibration-induced surface action also produces varying capacitance which can be detected for seismometer applications and the like.
Inventors
- 👤 Jack A. Ekchian
- 👤 Robert W. Hoffman
- 👤 Leon Ekchian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:54
CPC Classifications
G; G01; G01C; G01C9/00; G01C9/02; G01C9/06; G01C9/18; G01C9/20
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
167 words
A capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one but not all of said wall segments, the interior of at least one conductive wall segment being exposed, a conductive liquid-like medium contained inside said vessel covering a variable part of a least one wall segment with said dielectric coating and at least one wall segment without said dielectric coating, and electronic means electrically connected to at least one wall segment with said coating and at least one wall segment without said coating for producing an output related to the capacitance between said liquid-like medium and said one wall segment with said dielectric coating, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 2
Dependent Claim
167 words
A capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one but not all of said wall segments, the interior of at least one conductive wall segment being exposed, a conductive liquid-like medium contained inside said vessel covering a variable part of a least one wall segment with said dielectric coating and at least one wall segment without said dielectric coating, and electronic means electrically connected to at least one wall segment with said coating and at least one wall segment without said coating for producing an output related to the capacitance between said liquid-like medium and said one wall segment with said dielectric coating, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 3
Dependent Claim
12 words
The sensor of claim 1, wherein said wall segments are approximately spherical.
Claim 4
Dependent Claim
11 words
The sensor of claim 1, wherein said liquid-like medium includes mercury.
Claim 5
Dependent Claim
140 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, means inside said vessel and in communication with said liquid-like medium for damping the motion of said liquid-like medium, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 6
Dependent Claim
140 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, means inside said vessel and in communication with said liquid-like medium for damping the motion of said liquid-like medium, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 7
Dependent Claim
25 words
The sensor of claim 4, wherein said damping means includes non-conductive baffles mounted on the inside of said vessel and extending into said liquid-like medium.
Claim 8
Dependent Claim
23 words
The sensor of claim 4, wherein said damping means includes a non-conductive material of lower density floating on top of said liquid-like medium.
Claim 9
Dependent Claim
21 words
The sensor of claim 4, wherein said damping means includes means added to said liquid-like medium for making it more viscous.
Claim 10
Dependent Claim
20 words
The sensor of claim 4, wherein said damping means is a body inside the vessel immersed in said liquid-like medium.
Claim 11
Dependent Claim
129 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, said liquid-like medium including flowable conductive particulate material, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 12
Dependent Claim
129 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, said liquid-like medium including flowable conductive particulate material, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 13
Dependent Claim
131 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, said liquid-like medium including a slurry including conductive particulate material, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 14
Dependent Claim
131 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, said liquid-like medium including a slurry including conductive particulate material, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 15
Dependent Claim
150 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, said vessel being substantially completely filled with a non-conducting liquid mixed with a denser conductive material which precipitates to form said liquid-like medium when the vessel is held stationary, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 16
Dependent Claim
150 words
A liquid-like medium capacitive displacement sensor, comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, said vessel being substantially completely filled with a non-conducting liquid mixed with a denser conductive material which precipitates to form said liquid-like medium when the vessel is held stationary, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 17
Dependent Claim
12 words
The sensor of claim 1, wherein said vessel defines a spherical cavity.
Claim 18
Dependent Claim
29 words
The sensor of claim 12, wherein said one wall segment with said dielectric coating is a hemispherical segment, and said liquid-like medium fills approximately half of the spherical volume.
Claim 19
Dependent Claim
31 words
The sensor of claim 13, wherein said electronic means includes a capacitor controlled oscillator in which the control capacitance is the capacitance between the liquid-like medium and said one wall segment.
Claim 20
Dependent Claim
29 words
The sensor of claim 14, wherein said electronic means further includes a fixed frequency oscillator, and mixer means for mixing the outputs of said variable and fixed frequency oscillators.
Claim 21
Dependent Claim
36 words
The sensor of claim 15, wherein said electronic means further includes low pass filter means for filtering the output of said mixer means to produce a frequency output indicative of the relative inclination of said vessel.
Claim 22
Dependent Claim
35 words
The sensor of claim 16, wherein said electronic means further comprises capacitive means for adjusting the frequencies of said variable and fixed frequency oscillators to calibrate the frequency output of said low pass filter means.
Claim 23
Dependent Claim
15 words
The sensor of claim 12, further comprising a concentric spherical body mounted inside said vessel.
Claim 24
Dependent Claim
48 words
The sensor of claim 18, wherein said spherical body includes at least two insulated conductive wall segments, at least one of said wall segments having a dielectric coating, and insulated lead means extending through said vessel for providing electrical connections to said wall segments of said spherical body.
Claim 25
Dependent Claim
130 words
An inclinometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one but not all of said wall segments, the interior of at least one conductive wall segment being exposed, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating and at least one wall segment without said dielectric coating, and electronic means electrically connected to at least one wall segment with said coating and at least one wall segment without said coating for producing an output related to the capacitance between said liquid-like medium and said one wall segment with said dielectric coating,
Claim 26
Dependent Claim
130 words
An inclinometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one but not all of said wall segments, the interior of at least one conductive wall segment being exposed, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating and at least one wall segment without said dielectric coating, and electronic means electrically connected to at least one wall segment with said coating and at least one wall segment without said coating for producing an output related to the capacitance between said liquid-like medium and said one wall segment with said dielectric coating,
Claim 27
Dependent Claim
35 words
whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 28
Dependent Claim
35 words
whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 29
Dependent Claim
12 words
The inclinometer of claim 20, wherein said wall segments are approximately spherical.
Claim 30
Dependent Claim
11 words
The inclinometer of claim 20, wherein said liquid-like medium includes mercury.
Claim 31
Dependent Claim
136 words
An inclinometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, means inside said vessel and in communication with said liquid-like medium for damping the motion of said liquid-like medium, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 32
Dependent Claim
136 words
An inclinometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, means inside said vessel and in communication with said liquid-like medium for damping the motion of said liquid-like medium, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 33
Dependent Claim
164 words
A seismometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one but not all of said segments, the interior of at least one conductive wall segment being exposed, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating and at least one wall segment without said dielectric coating, and electronic means electrically connected to at least one wall segment with said coating and at least one wall segment without said coating for producing an output related to the capacitance between said liquid-like medium and said one wall segment with said dielectric coating, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 34
Dependent Claim
164 words
A seismometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one but not all of said segments, the interior of at least one conductive wall segment being exposed, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating and at least one wall segment without said dielectric coating, and electronic means electrically connected to at least one wall segment with said coating and at least one wall segment without said coating for producing an output related to the capacitance between said liquid-like medium and said one wall segment with said dielectric coating, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 35
Dependent Claim
12 words
The seismometer of claim 24, wherein said wall segments are approximately spherical.
Claim 36
Dependent Claim
11 words
The seismometer of claim 24, wherein said liquid-like medium includes mercury.
Claim 37
Dependent Claim
136 words
A seismometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, means inside said vessel and in communication with said liquid-like medium for damping the motion of said liquid-like medium, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 38
Dependent Claim
136 words
A seismometer comprising a vessel having a wall including at least two adjacent conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of at least one of said wall segments, a conductive liquid-like medium contained inside said vessel covering a variable part of at least one wall segment with said dielectric coating, means inside said vessel and in communication with said liquid-like medium for damping the motion of said liquid-like medium, and electronic means for producing an output related to the capacitance between said liquid-like medium and said one wall segment, whereby displacement of said vessel causes relative movement between said vessel and said liquid-like medium and a concomitant detectable change in the capacitance between said liquid-like medium and the wall segment with the dielectric coating.
Claim 39
Dependent Claim
167 words
A capacitive displacement cell, comprising a tubular housing, an electrically conductive end plug received in one end of said tubular housing, said end plug having an inside face transverse to the tubular axis, the inside face of said end plug having a spherical recess centered on said tubular axis, nonconductive cup means received in said tubular housing having a recess opposite said hemispherical recess in said end plug, a conductive insert received in said cup means recess, said insert having an opposed hemispherical recess concentric with said hemispherical recess in said end plug so as to form therewith a spherical cavity, a nonconductive washer means between the inside face of said end plug and said cup means with said insert for insulating said conductive insert from said conductive end plug, an electrical terminal contacting said conductive insert and extending through said nonconducting cup means, a uniform dielectric coating on the hemispherical recess of said conductive insert, and means for introducing a liquid medium into said spherical cavity.
Claim 40
Dependent Claim
167 words
A capacitive displacement cell, comprising a tubular housing, an electrically conductive end plug received in one end of said tubular housing, said end plug having an inside face transverse to the tubular axis, the inside face of said end plug having a spherical recess centered on said tubular axis, nonconductive cup means received in said tubular housing having a recess opposite said hemispherical recess in said end plug, a conductive insert received in said cup means recess, said insert having an opposed hemispherical recess concentric with said hemispherical recess in said end plug so as to form therewith a spherical cavity, a nonconductive washer means between the inside face of said end plug and said cup means with said insert for insulating said conductive insert from said conductive end plug, an electrical terminal contacting said conductive insert and extending through said nonconducting cup means, a uniform dielectric coating on the hemispherical recess of said conductive insert, and means for introducing a liquid medium into said spherical cavity.
Claim 41
Dependent Claim
25 words
The cell of claim 28, wherein said liquid medium introducing means includes a closeable port defined through said end plug communicating with said spherical cavity.
Claim 42
Dependent Claim
42 words
The cell of claim 29, further comprising a coaxial retaining ring, a coaxial annular recess defined around the circumference of said cup means receiving said retaining ring, and means for detachably affixing said retaining ring to the inside wall of said housing.
Claim 43
Dependent Claim
39 words
The cell of claim 28, further comprising electronic means in said housing connected to said electrical terminal and to said end plug for producing an output signal related to the capacitance between said liquid medium and said conductive insert.
Claim 44
Dependent Claim
44 words
The cell of claim 31, further comprising removable cap means closing the other end of said tubular housing, and p1 electrical connector means extending through said cap means electrically connected to said electronic means for making the output of said electrical means externally available.
Claim 45
Dependent Claim
27 words
The cell of claim 28, wherein said housing is electrically conductive, and further comprising means for electrically and mechanically affixing the end plug to the tubular housing.
Claim 46
Dependent Claim
137 words
A capacitive displacement sensor, comprising a vessel having a wall including at least two conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of said vessel covering said two wall segments, a conductive flowable material contained inside said vessel covering a variable part of said two wall segments, electrical terminal means connected to said two conductive wall segments respectively, and electronic means connected to said two terminals for producing an output related to the series capacitance between said flowable material and one wall segment and said flowable material and said other wall segment, whereby displacement of said vessel causes relative movement between said vessel and said flowable material and a concomitant detectable change in the series capacitance between the flowable material and the dielectric coated wall segments.
Claim 47
Dependent Claim
137 words
A capacitive displacement sensor, comprising a vessel having a wall including at least two conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating on the interior of said vessel covering said two wall segments, a conductive flowable material contained inside said vessel covering a variable part of said two wall segments, electrical terminal means connected to said two conductive wall segments respectively, and electronic means connected to said two terminals for producing an output related to the series capacitance between said flowable material and one wall segment and said flowable material and said other wall segment, whereby displacement of said vessel causes relative movement between said vessel and said flowable material and a concomitant detectable change in the series capacitance between the flowable material and the dielectric coated wall segments.
Claim 48
Dependent Claim
12 words
The sensor of claim 34, wherein said wall segments are approximately spherical.
Claim 49
Dependent Claim
14 words
The sensor of claim 35, wherein said wall segments define a closed spherical cavity.
Claim 50
Dependent Claim
11 words
The sensor of claim 34, wherein said flowable material is mercury.
Claim 51
Dependent Claim
26 words
The sensor of claim 34, further comprising means inside said vessel and in communication with said flowable material for damping the motion of said flowable material.
Claim 52
Dependent Claim
11 words
The sensor of claim 38, wherein said flowable material includes mercury.
Claim 53
Dependent Claim
149 words
A capacitive displacement sensor, comprising a vessel having a wall defining a spherical cavity composed of two mating hemispherical electrically conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating of uniform thickness over the entire hemispherical interior surface of one of said wall segments, a conductive flowable material filling approximately half the volume of said spherical cavity contained inside said vessel, means electrically connected to said wall segments for producing an output related to the capacitance between said flowable material and said one wall segment with said dielectric coating, whereby displacement of said vessel causes relative movement between said vessel and said flowable material and concomitant change in the variable part of the dielectric coated wall segment covered by said flowable material thus changing the capacitance therebetween, the other wall segment acting as an electrode in contact with said conductive flowable material.
Claim 54
Dependent Claim
149 words
A capacitive displacement sensor, comprising a vessel having a wall defining a spherical cavity composed of two mating hemispherical electrically conductive wall segments, means for electrically insulating said wall segments from each other, a dielectric coating of uniform thickness over the entire hemispherical interior surface of one of said wall segments, a conductive flowable material filling approximately half the volume of said spherical cavity contained inside said vessel, means electrically connected to said wall segments for producing an output related to the capacitance between said flowable material and said one wall segment with said dielectric coating, whereby displacement of said vessel causes relative movement between said vessel and said flowable material and concomitant change in the variable part of the dielectric coated wall segment covered by said flowable material thus changing the capacitance therebetween, the other wall segment acting as an electrode in contact with said conductive flowable material.
Claim 55
Dependent Claim
11 words
The sensor of claim 40, wherein said flowable material is mercury.
Claim 56
Dependent Claim
26 words
The sensor of claim 40, further comprising means inside said vessel and in communication with said flowable material for damping the motion of said flowable material.
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USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 1989-11-24 | 1990-05-26 | 1990-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-24 | 1994-05-26 | 1994-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-24 | 1998-05-26 | 1998-11-25 | $7700.00 | Window Closed / Lapsed |