Patent US2089609A successfully refreshed from Google Patents.
US4903530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid level sensing system
Assignee: Individual
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Filing: 1988-12-08
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Granted: 1990-02-27
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Expires: 2008-12-08
Abstract
Abstract Multiple contact sensors located at axially spaced measurement zones, inside or outside of an elongated probe, closes a variable resistance circuit through the conducting substance being monitored, with monitoring means being a three-way or multicolored light emitting diode, which in connection with an AC power source and a transistor, changes color and luminosity as the substance being monitored reaches the various levels of the contact sensors.
Inventors
- 👤 Harold L. Hull
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:39
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/24; G01F23/241; G01F23/243; G01F23/242
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
A liquid level sensor conductive system comprising; means to connect to a power source, a probe, means for mounting said probe in a liquid conductive substance, a plurality of spaced contact elements cooperating with said probe, means for mounting said probe and said spaced contact elements at various pre-determined levels of said liquid conductive substance, a tri-colored light emitting diode in an indicating electrical box unit, means to change the current flow to said diode from direct current to reverse direct current to alternating current, means to conduct said current flow from said means to connect to a power source, through said diode, through said means to change the direction of current flow and through said contact elements when said contact elements are covered with said liquid conductive substance.
Claim 2
Dependent Claim
129 words
A liquid level sensor conductive system comprising; means to connect to a power source, a probe, means for mounting said probe in a liquid conductive substance, a plurality of spaced contact elements cooperating with said probe, means for mounting said probe and said spaced contact elements at various pre-determined levels of said liquid conductive substance, a tri-colored light emitting diode in an indicating electrical box unit, means to change the current flow to said diode from direct current to reverse direct current to alternating current, means to conduct said current flow from said means to connect to a power source, through said diode, through said means to change the direction of current flow and through said contact elements when said contact elements are covered with said liquid conductive substance.
Claim 3
Dependent Claim
20 words
The device of claim 1 in which said contact elements are substantially longer in their length than in their girth.
Claim 4
Dependent Claim
19 words
The device of claim 1 in which said contact elements are mounted on said probe in a vertical position.
Claim 5
Dependent Claim
24 words
The device of claim 1 in which said means to change the current flow from direct current to reverse direct current is a transistor.
Claim 6
Dependent Claim
19 words
The device of claim 1 in which said probe and said contact elements are made of corrosive resistant materials.
Claim 7
Dependent Claim
13 words
The device of claim 1 in which said liquid conductive substance is water.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-26 | 1993-08-28 | 1994-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-26 | 1997-08-28 | 1998-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-26 | 2001-08-28 | 2002-02-27 | $7700.00 | Window Closed / Lapsed |