Patent US4982606A successfully refreshed from Google Patents.
US4982606A
Expired / Lapsed
US
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Fluid level sensor and controller
Assignee: Alliance Laundry Systems LLC
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Filing: 1989-03-06
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Granted: 1991-01-08
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Expires: 2009-03-06
Abstract
Abstract A fluid level sensor for determining the amount of liquid in a container. Thin metal plates are placed parallely adjacent each other to form a capacitor cell coated with a non-hygroscopic film. The plates are mounted on the walls of the container containing fluid. As the fluid covers more surface area of the capacitor plates, the dielectric properties of the fluid increase the capacitance of the cell proportionally. The plates are connected to an oscillator whose output frequency varies with the change in container fluid levels. By monitoring these frequency changes, the container fluid levels of the fluid in the container can be controlled.
Inventors
- 👤 Joseph R. Adamski
- 👤 Donald A. Coates
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:23
CPC Classifications
D; D06; D06F; D06F39/00; D06F39/08; D06F39/087; G; G01; G01F; G01F23/00; G01F23/22; G01F23/26; G01F23/263; G01F23/266; G01F23/268; G05; G05D; G05D9/00; G05D9/12; Y; Y10; Y10T; Y10T137/00; Y10T137/7287; Y10T137/729
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
103 words
An apparatus for sensing the level of liquid in a container comprising: first and second parallel metal plates having opposingly facing flat surfaces and providing a capacitance; means for supporting said plates inside said container; insulating spacing means, attached to said first and second plates for maintaining a constant spacing between said first and second plates; and means electrically coupled to said plates for detecting said capacitance and for generating in response to said capacitance a signal indicating the level of liquid in said container; wherein said first and second parallel metal plates are shaped to support said detecting and signal generating means.
Claim 2
Independent Claim
103 words
An apparatus for sensing the level of liquid in a container comprising: first and second parallel metal plates having opposingly facing flat surfaces and providing a capacitance; means for supporting said plates inside said container; insulating spacing means, attached to said first and second plates for maintaining a constant spacing between said first and second plates; and means electrically coupled to said plates for detecting said capacitance and for generating in response to said capacitance a signal indicating the level of liquid in said container; wherein said first and second parallel metal plates are shaped to support said detecting and signal generating means.
Claim 3
Dependent Claim
34 words
The apparatus as recited in claim 1 wherein each of said first and second plates has a portion perpendicular to said opposingly facing flat surface, said portion supporting said detecting and signal generating means.
Claim 4
Dependent Claim
19 words
The apparatus as recited in claim 1 further comprising a corrosion resistant coating means for encasing said metal plates.
Claim 5
Dependent Claim
24 words
The apparatus as recited in claim 1 wherein said means for supporting said plates inside said container supports said plates in a vertical position.
Claim 6
Dependent Claim
112 words
A washing machine comprising: an outer tub; an inner tub disposed within said outer tub; an agitator positioned in said inner tub; means for driving said agitator; and means for sensing the level of liquid in said outer tub, said sensing means comprising: (a) first and second parallel metal plates having opposingly facing flat surfaces; (b means for supporting said plates inside said outer tub; (c) insulating spacing means, attached to said first and second plates, for maintaining a constant spacing between said first and second plates; and (d) means attached to a portion of said first and second plates for generating a signal indicating the level of liquid in said tub.
Claim 7
Dependent Claim
112 words
A washing machine comprising: an outer tub; an inner tub disposed within said outer tub; an agitator positioned in said inner tub; means for driving said agitator; and means for sensing the level of liquid in said outer tub, said sensing means comprising: (a) first and second parallel metal plates having opposingly facing flat surfaces; (b means for supporting said plates inside said outer tub; (c) insulating spacing means, attached to said first and second plates, for maintaining a constant spacing between said first and second plates; and (d) means attached to a portion of said first and second plates for generating a signal indicating the level of liquid in said tub.
Claim 8
Dependent Claim
26 words
The washing machine as recited in claim 5 further comprising means for displaying the level of liquid in said outer tub in response to said frequency.
Claim 9
Dependent Claim
24 words
The washing machine recited in claim 5 wherein said signal has a frequency proportional to the level of the liquid in said outer tub.
Claim 10
Dependent Claim
24 words
The washing machine recited in claim 5 further comprising means, responsive to said signal for adjusting the level of liquid within said outer tub.
Claim 11
Dependent Claim
27 words
The washing machine recited in claim 5 wherein said first and second plates are spaced by greater than approximately 0.0625 inches and less than approximately 0.125 inches.
Claim 12
Dependent Claim
19 words
The washing machine recited in claim 5 wherein said first and second plates are coated with a "TEFLON" material.
Claim 13
Dependent Claim
19 words
The washing machine recited in claim 5 wherein said signal generating means is mounted on a printed circuit board.
Claim 14
Dependent Claim
20 words
The washing machine recited in claim 11 wherein said first and second plates are shaped to support said circuit board.
Claim 15
Dependent Claim
23 words
The washing machine recited in claim 5 wherein said first and second plates are mounted within said outer tub to contact said liquid.
Claim 16
Independent Claim
124 words
A method of sensing the level of liquid in a washing machine comprising the steps of: positioning first and second parallel metal plates having opposingly facing flat surfaces in a substantially vertical position within the liquid within said machine; coating said plates with a non-corrosive material; maintaining a constant spacing by an insulating spacer between said first and second plates of less than approximately 0.5 inches; sensing the capacitance between the first and second plates; generating a signal having a frequency proportional to the level of liquid in said washing machine in response to said capacitance; and attaching a circuit board to said metal plates, said circuit board containing circuitry that senses the capacitance between said first and second plates and generates said signal.
Claim 17
Independent Claim
124 words
A method of sensing the level of liquid in a washing machine comprising the steps of: positioning first and second parallel metal plates having opposingly facing flat surfaces in a substantially vertical position within the liquid within said machine; coating said plates with a non-corrosive material; maintaining a constant spacing by an insulating spacer between said first and second plates of less than approximately 0.5 inches; sensing the capacitance between the first and second plates; generating a signal having a frequency proportional to the level of liquid in said washing machine in response to said capacitance; and attaching a circuit board to said metal plates, said circuit board containing circuitry that senses the capacitance between said first and second plates and generates said signal.
Claim 18
Dependent Claim
21 words
The method as recited in claim 14 wherein said first and second plates are spaced by less than approximately 0.5 inches.
Claim 19
Dependent Claim
25 words
The method as recited in claim 14 further comprising the step of controlling the level of liquid in said machine in response to said signal.
Claim 20
Dependent Claim
46 words
The apparatus as recited in claim 14 further comprising the steps of: determining a time period corresponding to the frequency of said signal; comparing said time period to a pre-stored value; and changing the level of liquid in said washing machine in response to said comparison.
Claim 21
Dependent Claim
29 words
The method as recited in claim 14 further comprising the step of displaying the changes in the level of liquid in said washing machine in response to said signal.
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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) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |