US3911744A
Expired / Lapsed
US
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Liquid level gauging apparatus
Assignee: Liquidometer Corp
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Filing: 1974-04-10
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Granted: 1975-10-14
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Expires: 1994-04-10
Abstract
Abstract A liquid level gauge which utilizes the electrical resistance of the liquid being gauged to provide readings. An immersion unit is adapted to be disposed vertically in the liquid storage vessel. It comprises an elongate conducting member coextensive with a row of insulatedly-mounted electrodes which latter are individually connected to an indicating type selector switch means. The conducting member is connected to one input of an extremely sensitive electronic amplifier, which in turn drives an output indicating meter. The indicating selector switch means can apply an exciting potential to any of the electrodes, which results in a driving signal applied to the amplifier only if the excited electrode is submerged. An indicator light signals the amplifier output under such circumstances. By sweeping the selector switch means over its range and noting the point at which the indicator light becomes illuminated, it is possible to ascertain the location of the upper-most electrode which is submerged and thus determine the level of fluid in the tank. In addition, the indicating meter provides a reading corresponding to the percentage or portion of the electrode which is submerged, and thus gives a finer degree of accuracy to the level measurement.
Inventors
- 👤 Harrison F Edwards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:29
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/24; G01F23/241
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
153 words
A liquid-level gauge comprising, in combination: a. an upright conducting probe adapted for contact at a multiplicity of levels with the liquid to be gauged, b. an upright row of electrodes insulated from each other and adapted for immersion in said liquid in proximity to said probe, c. mEans for successively applying to said electrodes a finite energizing voltage with respect to a fixed reference potential, and for simultaneously indicating any electrodes thus energized, d. voltage responsive detector means having a voltage sensitive input terminal connected to said probe for sensing potential therefrom as the energizing voltage is applied to the electrodes, said detector means providing an indicating output signal in response to energization of an electrode which is at least partially submerged in the liquid, and e. means for maintaining any electrodes which are not energized by the energizing voltage at a potential substantially equal to the potential of the conducting probe.
Claim 2
Dependent Claim
153 words
A liquid-level gauge comprising, in combination: a. an upright conducting probe adapted for contact at a multiplicity of levels with the liquid to be gauged, b. an upright row of electrodes insulated from each other and adapted for immersion in said liquid in proximity to said probe, c. mEans for successively applying to said electrodes a finite energizing voltage with respect to a fixed reference potential, and for simultaneously indicating any electrodes thus energized, d. voltage responsive detector means having a voltage sensitive input terminal connected to said probe for sensing potential therefrom as the energizing voltage is applied to the electrodes, said detector means providing an indicating output signal in response to energization of an electrode which is at least partially submerged in the liquid, and e. means for maintaining any electrodes which are not energized by the energizing voltage at a potential substantially equal to the potential of the conducting probe.
Claim 3
Dependent Claim
26 words
The invention as defined in claim 1, wherein: a. said voltage applying means comprises a switching device for successively applying the energizing voltage to the electrodes.
Claim 4
Dependent Claim
36 words
The invention as defined in claim 1, and further including: a. an electrical guard comprising a conducting cylinder encircling said conducting probe and said electrodes, and b. means electrically connecting said guard to said detector means.
Claim 5
Dependent Claim
33 words
The invention as defined in claim 1, wherein: a. the detector means comprises a high input impedance amplifier having an input terminal connected with the conducting member, and further having an output terminal.
Claim 6
Dependent Claim
26 words
The invention as defined in claim 4 wherein: a. the detector means further includes an electrical indicating meter connected to the output terminal of the amplifier.
Claim 7
Dependent Claim
30 words
The invention as defined in claim 4 wherein: a. an input terminal of the amplifier is connected to the output circuit thereof to provide a feedback control for the amplifier.
Claim 8
Dependent Claim
39 words
The invention as defined in claim 1, wherein: a. said detector means comprises an amplifier and an electrically energized light source powered by said amplifier, for providing visual indications as the switching device successively applies potential to the electrodes.
Claim 9
Dependent Claim
18 words
The invention as defined in claim 7, wherein: a. said electrically energized light source comprises a light-emitting diode.
Claim 10
Dependent Claim
186 words
A liquid-level gauge comprising, in combination: a. an upright, conducting probe adapted for contact at a multiplicity of levels with the liquid to be gauged, b. an upright row of electrodes insulated from each other and adapted for immersion in said liquid in proximity to said probe, c. a voltage responsive power amplifier having voltage sensitive high impedance input circuitry and input terminals associated therewith, and having a lower impedance output circuit, d. an electric indicator in said output circuit, responsive to the output power of the amplifier, e. said upright conducting probe being connected to one of said input terminals, f. a plurality of high-value resistors connected respectively to the electrodes of said row and having a common lead connected to the output circuit of said amplifier, and g. means including a selecting switch device for successively applying to said electrodes a finite polarizing potential with respect to a fixed reference potential and for simultaneously indicating any electrode thus polarized, said indicator providing a signal in response to application of a polarizing potential to an electrode which is at least partially submerged in the liquid.
Claim 11
Dependent Claim
186 words
A liquid-level gauge comprising, in combination: a. an upright, conducting probe adapted for contact at a multiplicity of levels with the liquid to be gauged, b. an upright row of electrodes insulated from each other and adapted for immersion in said liquid in proximity to said probe, c. a voltage responsive power amplifier having voltage sensitive high impedance input circuitry and input terminals associated therewith, and having a lower impedance output circuit, d. an electric indicator in said output circuit, responsive to the output power of the amplifier, e. said upright conducting probe being connected to one of said input terminals, f. a plurality of high-value resistors connected respectively to the electrodes of said row and having a common lead connected to the output circuit of said amplifier, and g. means including a selecting switch device for successively applying to said electrodes a finite polarizing potential with respect to a fixed reference potential and for simultaneously indicating any electrode thus polarized, said indicator providing a signal in response to application of a polarizing potential to an electrode which is at least partially submerged in the liquid.
Claim 12
Dependent Claim
25 words
A liquid-level gauge as in claim 9, wherein: a. the electric indicator comprises a current-responsive meter, for measuring the current output of the power amplifier.
Claim 13
Dependent Claim
45 words
A liquid-level gauge as in claim 9, wherein: a. the selecting switch device comprises a rotary switch blade and a pointer connected therewith, arcuately arranged contacts cooperable with the blade and connected with the electrodes, respectively, and a graduated scale over which the pointer travels.
Claim 14
Dependent Claim
71 words
A liquid-level gauge as in claim 9, wherein: a. the selecting switch device comprises a pair of rotary swItch blades and pointers connected therewith, two sets of arcuately arranged contacts cooperable respectively with said blades, and a pair of graduated scales over which the pointers respectively travel, b. one of said rotary switch blades being electrically connected to a contact of the set which is associated with the other switch blade.
Claim 15
Dependent Claim
43 words
A liquid level gauge as in claim 9, and further including: a. an electrical guard comprising a conducting cylinder encircling said conducting probe and said upright row of electrodes, and b. means electrically connecting said guard to the output circuit of the amplifier.
Claim 16
Dependent Claim
46 words
A liquid level gauge as in claim 13, and further including: a. an electrical lead extending from the conducting probe to said one input terminal, and b. a tubular shield disposed around said lead, constituting the means which connects the guard to the amplifier output circuit.
Claim 17
Dependent Claim
45 words
A liquid level gauge as in claim 9, and further including: a. an electrically-energized light source, and b. power means connected to said light source and to the output of the amplifier, for operatively energizing said source when the amplifier output attains a predetermined level.
Claim 18
Dependent Claim
45 words
A liquid level gauge as in claim 9, wherein: a. the means for applying a polarizing potential comprises a battery power supply providing positive and negative potentials, and b. means for energizing the power amplifier with said positive and negative potentials from the battery supply.
Claim 19
Dependent Claim
49 words
A liquid level gauge as in claim 9, wherein: a. said indicator comprises a meter, and includes means connected to said meter, providing for full scale deflection of the latter when the switch device is supplying potential to any electrode which is fully immersed in the liquid being gauged.
Claim 20
Dependent Claim
41 words
A liquid level gauge as in claim 17, wherein: a. the indicator has a zero reading when the switch device is supplying potential to any electrode not contacting the liquid being gauged, b. said indicator having a straight line response characteristic.
Claim 21
Dependent Claim
48 words
A liquid level gauge as in claim 18 and further including: a. a calibration device connected in circuit with said indicator, for establishing a predetermined setting of the same for positions of the switch device which supply potential to an electrode which is completely submerged in the liquid.
Claim 22
Dependent Claim
27 words
A liquid level gauge as in claim 9 and further including: a. means connecting the amplifier output circuit to said other input terminal, providing a feedback thereto.
Claim 23
Dependent Claim
35 words
A liquid level gauge as in claim 20, and further including: a. an electrical guard shielding said conducting member and upright row of electrodes, and b. means connecting said guard to the amplifier output circuit.
Claim 24
Dependent Claim
224 words
In a liquid storage installation, in combination: a. a storage tank having a large body of liquid stored therein, b. an upright, electrically conducting probe immersed in said body of liquid and adapted for contact at a multiplicity of levels with the liquid to be gauged, said probe assuming a finite potential by virtue of said immersion in the liquid, c. a probe device cooperable with said probe, said probe device comprising an upright row of electrodes insulated from each other and adapted for immersion in said body of liquid in proximity to said first-mentioned probe. d. means for applying an energizing voltage to said electrodes in succession. e. said liquid being characterized by the property of establishing a cooperable relationship between said conducting probe and different, consecutively higher or consecutively lower electrodes as the level of the body of liquid in the tank respectively rises or falls, f. voltage responsive detector means having a voltage sensitive input terminal connected with said probe and being responsive to said relationship, designating which of the said electrodes is or are involved in said relationsHip, thereby to provide an indication of the level of the liquid in the tank, and g. means for maintaining any electrodes which are not energized by the energizing voltage at a potential substantially equal to the potential assumed by the conducting probe.
Claim 25
Dependent Claim
224 words
In a liquid storage installation, in combination: a. a storage tank having a large body of liquid stored therein, b. an upright, electrically conducting probe immersed in said body of liquid and adapted for contact at a multiplicity of levels with the liquid to be gauged, said probe assuming a finite potential by virtue of said immersion in the liquid, c. a probe device cooperable with said probe, said probe device comprising an upright row of electrodes insulated from each other and adapted for immersion in said body of liquid in proximity to said first-mentioned probe. d. means for applying an energizing voltage to said electrodes in succession. e. said liquid being characterized by the property of establishing a cooperable relationship between said conducting probe and different, consecutively higher or consecutively lower electrodes as the level of the body of liquid in the tank respectively rises or falls, f. voltage responsive detector means having a voltage sensitive input terminal connected with said probe and being responsive to said relationship, designating which of the said electrodes is or are involved in said relationsHip, thereby to provide an indication of the level of the liquid in the tank, and g. means for maintaining any electrodes which are not energized by the energizing voltage at a potential substantially equal to the potential assumed by the conducting probe.
Claim 26
Dependent Claim
18 words
The invention as defined in claim 22, wherein: a. said cooperable relationship comprises the conductance of the liquid.
Claim 27
Dependent Claim
23 words
The invention as defined in claim 23, wherein: a. said detector means comprises means for applying energizing voltages to some of said electrodes.
Claim 28
Dependent Claim
40 words
The invention as defined in claim 24, wherein: a. said applying means comprises a switching device for successively applying the energizing voltages to said electrodes, b. said detector means comprising an amplifier and indicator connected with said upright conducting probe.
Claim 29
Dependent Claim
26 words
The invention as defined in claim 25, wherein: a. said switching device includes means for indicating which of said electrodes is energized at any given time.
Claim 30
Dependent Claim
38 words
The invention as defined in claim 22 and further including: a. an electrical guard comprising a conducting cylinder encircling said conducting probe and said cooperable probe device, and b. means electrically connecting said guard to said detector means.
Claim 31
Dependent Claim
44 words
The invention as defined in claim 22 wherein: a. the detector means comprises a high input impedance amplifier having an input terminal connected with the conducting probe, and further having an output terminal, and b. an electrical indicating meter connected to said output terminal.
Claim 32
Dependent Claim
45 words
The invention as defined in claim 22, wherein: a. an electrical guard comprising a conducting cylinder encircling said conducting probe and said cooperable probe device, and b. electronic means for maintaining said guard at substantially the same potential as that sensed by the conducting probe
Claim 33
Dependent Claim
205 words
A liquid-level gauge comprising, in combination: a. an upright conducting probe adapted for contact at a multiplicity of levels with the liquid to be gauged, b. an upright row of electrodes insulated from each other and adapted for immersion in said liquid in proximity to said probe, c. means for successively applying to said electrodes a finite energizing voltage with respect to a fixed reference potential, and for simultaneously indicating any electrodes thus energized, d. means independent of the liquid being gauged, and including polarized circuits connected with the electrodes, for maintaining any of the latter, which are not energized by the energizing voltage, at a potential substantially equal to the potential of the conducting probe, e. voltage responsive detector means having a voltage sensitive input terminal connected to said probe for sensing potential therefrom as the energizing voltage is applied to the electrodes, said detector means providing an indicating output signal in response to energization of an electrode which is at least partially submerged in the liquid, f. an electrical guard comprising a conducting cylinder encircling said conducting probe and said electrodes, and g. low impedance electronic means for maintaining said guard at substantially the same potential as that sensed by the conducting probe.
Claim 34
Dependent Claim
205 words
A liquid-level gauge comprising, in combination: a. an upright conducting probe adapted for contact at a multiplicity of levels with the liquid to be gauged, b. an upright row of electrodes insulated from each other and adapted for immersion in said liquid in proximity to said probe, c. means for successively applying to said electrodes a finite energizing voltage with respect to a fixed reference potential, and for simultaneously indicating any electrodes thus energized, d. means independent of the liquid being gauged, and including polarized circuits connected with the electrodes, for maintaining any of the latter, which are not energized by the energizing voltage, at a potential substantially equal to the potential of the conducting probe, e. voltage responsive detector means having a voltage sensitive input terminal connected to said probe for sensing potential therefrom as the energizing voltage is applied to the electrodes, said detector means providing an indicating output signal in response to energization of an electrode which is at least partially submerged in the liquid, f. an electrical guard comprising a conducting cylinder encircling said conducting probe and said electrodes, and g. low impedance electronic means for maintaining said guard at substantially the same potential as that sensed by the conducting probe.
Claim 35
Dependent Claim
38 words
The invention as set forth in claim 30 and further including: a. conductive means for maintaining any electrodes which are not energized by the energizing voltage at a potential substantially equal to the potential of the conducting probe.
Claim 36
Dependent Claim
25 words
The invention as set forth in claim 32, wherein: a. said conductive means comprises a plurality of high value resistors connected respectively to said electrodes.
Claim 37
Dependent Claim
78 words
The invention as defined in claim 30, wherein: a. said detector means comprises an amplifier having an input terminal connected with said conducting probe device and a meter connected to said amplifier. b. said electrodes having a finite vertical dimension, respectively, such that when a particular electrode is polarized and partially submerged, the potential sensed by the conducting probe device and hence the meter reading varies as a function of the degree of submergence of the particular electrode.
Claim 38
Dependent Claim
16 words
The invention as defined in claim 33, wherein: a. the amplifier has a unity voltage gain.
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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) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |