Patent US5613399A successfully refreshed from Google Patents.
US5613399A
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Method for liquid level detection
Assignee: HANNAN - NICKOLIN INTELLECTUAL PROPERTIES LLC
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Filing: 1995-04-17
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Granted: 1997-03-25
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Expires: 2015-04-17
Abstract
Abstract A digital liquid level sensing apparatus and method for detecting variations in the dielectric of a substance being sensed. The apparatus includes a capacitive element array which is disposed in a fluid to be measured and which includes a plurality of individual (i.e., segmented) input plates positioned along an axis of measurement of the fluid to be detected. The array also includes a common output plate having a length sufficient to span the entire accumulated length of the input plates. A controller sequentially applies DC excitation pulses to the input plates which cause a series of output currents to be coupled onto the output plate. The output currents are input to a current-to-voltage amplifier which generates a series of corresponding analog output voltages. The analog output voltages are then input to a peak voltage detector circuit to generate a series of peak voltage signals representative of the magnitudes of the analog output voltages. The controller converts each of the peak voltage signals into a corresponding digital value and stores each of the digital values in an on-board memory. The controller then sequentially compares each of the values against at least one predetermined reference value indicative of an output produced by an input plate disposed in air until a predetermined difference is detected between the reference value and any one of the stored digital values. This indicates a predetermined difference in the dielectric, thus indicating that a corresponding input plate is at least partially submerged in fluid.
Inventors
- 👤 Alan R. Hannan
- 👤 Thomas M. Nickolin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:07
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/26; G01F23/263; G01F23/265; G01F23/266; G01F23/268
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
222 words
A method for detecting a level of a fluid within a fluid reservoir, the method comprising: disposing a probe in said reservoir, wherein said probe includes a plurality of individually excitable input plates and a common output plate, said probe being positioned in said reservoir such that at least a portion of said output plate and a sub-plurality of said plurality of input plates are disposed in said fluid; determining an electrical reference signal representative of the electrical output signal which would be generated by one of said input plates when said one input plate is disposed completely above an upper level of said fluid; applying an electrical signal to each one of said input plates, sequentially, one at a time, to electrically excite each of said input plates and to generate a series of electrical signals; sequentially reading said output signals generated on said output plate as said input plates are electrically excited; comparing said output signals sequentially with said electrical reference signal; determining from said comparison which ones of said input plates are not disposed completely above said upper level of said fluid disposed in said fluid; and extrapolating from said input plates that are not disposed above said upper level of said fluid what a level of said fluid is within said reservoir relative to a known full level.
Claim 2
Independent Claim
222 words
A method for detecting a level of a fluid within a fluid reservoir, the method comprising: disposing a probe in said reservoir, wherein said probe includes a plurality of individually excitable input plates and a common output plate, said probe being positioned in said reservoir such that at least a portion of said output plate and a sub-plurality of said plurality of input plates are disposed in said fluid; determining an electrical reference signal representative of the electrical output signal which would be generated by one of said input plates when said one input plate is disposed completely above an upper level of said fluid; applying an electrical signal to each one of said input plates, sequentially, one at a time, to electrically excite each of said input plates and to generate a series of electrical signals; sequentially reading said output signals generated on said output plate as said input plates are electrically excited; comparing said output signals sequentially with said electrical reference signal; determining from said comparison which ones of said input plates are not disposed completely above said upper level of said fluid disposed in said fluid; and extrapolating from said input plates that are not disposed above said upper level of said fluid what a level of said fluid is within said reservoir relative to a known full level.
Claim 3
Dependent Claim
47 words
The method of claim 1, further comprising the step of determining what percentage of each of said input plates is submerged in said fluid; and from said percentage coverage of each of said input plates, further extrapolating a precise level of said fluid within said fluid reservoir.
Claim 4
Independent Claim
206 words
A method for detecting a level of a fluid within a fluid reservoir, method comprising: disposing a probe in said reservoir, wherein said probe includes a plurality of individually excitable input plates and a common output plate, said probe being positioned in said reservoir such that a least a portion of said output plate and a sub-plurality of said input plates are disposed in said fluid; providing an electrical reference signal being indicative of an input plate being disposed above an upper level of said fluid; applying an electrical signal to each one of said input plates, sequentially, one at a time, to electrically excite each said input plate and to generate a series of electrical signals; sequentially reading said output signals generated on said output plate as said input plates are electrically excited; comparing said output signals sequentially with said electrical reference signal to determine which one or ones of said input plates are not disposed completely above said upper level of said fluid; and extrapolating, from said comparison of said output signals and said electrical reference signal, without measuring the capacitance at any one of said input plates, what an approximate level of said fluid is within said reservoir to a known full level.
Claim 5
Independent Claim
206 words
A method for detecting a level of a fluid within a fluid reservoir, method comprising: disposing a probe in said reservoir, wherein said probe includes a plurality of individually excitable input plates and a common output plate, said probe being positioned in said reservoir such that a least a portion of said output plate and a sub-plurality of said input plates are disposed in said fluid; providing an electrical reference signal being indicative of an input plate being disposed above an upper level of said fluid; applying an electrical signal to each one of said input plates, sequentially, one at a time, to electrically excite each said input plate and to generate a series of electrical signals; sequentially reading said output signals generated on said output plate as said input plates are electrically excited; comparing said output signals sequentially with said electrical reference signal to determine which one or ones of said input plates are not disposed completely above said upper level of said fluid; and extrapolating, from said comparison of said output signals and said electrical reference signal, without measuring the capacitance at any one of said input plates, what an approximate level of said fluid is within said reservoir to a known full level.
References Cited (Backward Citations)
US2519668A
Cited
US2544012A
Cited
US2621517A
Cited
US2638000A
Cited
US2651940A
Cited
US2648058A
Cited
US2751531A
Cited
US2868015A
Cited
US2866337A
Cited
US3343415A
Cited
US3391547A
Cited
US3534606A
Cited
US3552209A
Cited
US3620080A
Cited
SU381911A1
Cited
US3935739A
Cited
US4086528A
Cited
US4173893A
Cited
SU748138A2
Cited
US4235106A
Cited
US4258422A
Cited
US4266144A
Cited
GB2066961A
Cited
GB2074325A
Cited
US4350039A
Cited
JPS58123431A
Cited
US4417473A
Cited
US4470008A
Cited
US4499766A
Cited
EP0103321A1
Cited
US4553434A
Cited
US4545020A
Cited
US4589077A
Cited
US4676101A
Cited
US5142909A
Cited
US4780705A
Cited
US4841227A
Cited
US4987776A
Cited
US5103368A
Cited
FR2662249A1
Cited
US5207098A
Cited
US5138880A
Cited
EP0538182A1
Cited
US5423214A
Cited
US5315872A
Cited
US5437184A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-03-24 | 2000-09-23 | 2001-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-03-24 | 2004-09-23 | 2005-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-03-24 | 2008-09-23 | 2009-03-25 | $7700.00 | Window Closed / Lapsed |