US4333354A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid flow sensors
Assignee: DAVID C GOODMAN
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Filing: 1980-05-15
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Granted: 1982-06-08
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Expires: 2000-05-15
Abstract
Abstract The disclosed sensors convert flow of liquid along a passage into electrical signals to represent rate or volume of the liquid flow. Vanes of a rotor are driven by the liquid so as to sweep past plural excitation and sensing electrodes that pass current through the liquid and sense the changing impedance caused by the vanes. The impedance of the liquid portion of the sensor circuit is modified at a frequency representing the travel of rotor vanes past the electrodes.
Inventors
- 👤 Murray F. Feller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 12:29
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/05; G01F1/10
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
171 words
A liquid flow sensor for water or similar liquid having some electrical conductivity, including a rotor adapted to be rotated about its axis by flowing liquid and having vanes of much higher resistivity than that of the liquid, means for supporting the rotor within a wall defining a liquid flow passage whereby rotation of the rotor may be calibrated in terms of liquid flow within the wall, and an electric circuit for producing signals representing the flow of the liquid, said circuit including plural excitation and sensing electrodes at least two of which are disposed in proximity to the path of said vanes, said electrodes being exposed to the liquid and said two electrodes acting in the absence of said rotor, to form a pattern of paths of current therebetween, said vanes being movable successively into a position clear of substantial current paths between said two electrodes and into positions wherein a substantial portion of said pattern of paths would extend through the thickness of said vanes but is suppressed thereby.
Claim 2
Dependent Claim
171 words
A liquid flow sensor for water or similar liquid having some electrical conductivity, including a rotor adapted to be rotated about its axis by flowing liquid and having vanes of much higher resistivity than that of the liquid, means for supporting the rotor within a wall defining a liquid flow passage whereby rotation of the rotor may be calibrated in terms of liquid flow within the wall, and an electric circuit for producing signals representing the flow of the liquid, said circuit including plural excitation and sensing electrodes at least two of which are disposed in proximity to the path of said vanes, said electrodes being exposed to the liquid and said two electrodes acting in the absence of said rotor, to form a pattern of paths of current therebetween, said vanes being movable successively into a position clear of substantial current paths between said two electrodes and into positions wherein a substantial portion of said pattern of paths would extend through the thickness of said vanes but is suppressed thereby.
Claim 3
Dependent Claim
29 words
A liquid-flow sensor as in claim 1 for use with tap water wherein the rotor is of a plastic whose resistivity is much greater than that of tap water.
Claim 4
Dependent Claim
45 words
A liquid-flow sensor as in claim 1 wherein the electric energizing means is alternating-current means having a frequency that is much higher than the highest frequency at which successive vanes of the rotor pass the electrodes over the range of flow rates to be observed.
Claim 5
Dependent Claim
56 words
A liquid-flow sensor as in claim 1 wherein plural electrodes comprising at least three electrodes are included having respective portions exposed to the liquid, and wherein the circuit includes an alternating-current supply having opposite terminals connected to two of the electrodes and wherein the output circuit includes at least one electrode other than said two electrodes.
Claim 6
Dependent Claim
26 words
A liquid-flow sensor as in claim 4 wherein terminals of an output circuit are connected, respectively, to said other electrode and to said alternating current supply.
Claim 7
Dependent Claim
35 words
A liquid-flow sensor as in claim 4 wherein terminals of an output circuit are connected, respectively, to said other electrode and to the mean potential point of said alternating current supply between said two electrodes.
Claim 8
Dependent Claim
30 words
A liquid-flow sensor as in claim 1, including a pipe forming said wall and wherein said vanes have edges of substantial length along the pipe and are spaced narrowly therefrom.
Claim 9
Dependent Claim
25 words
A liquid-flow sensor as in claim 1, wherein said wall is of metal and is connected to a point of stable potential in said circuit.
Claim 10
Dependent Claim
37 words
A liquid-flow sensor as in claim 1, wherein said wall is a pipe of much greater diameter than said vaned rotor and in which said electrodes and said rotor are supported as a probe within the pipe.
Claim 11
Dependent Claim
35 words
A liquid-flow sensor as in claim 1 wherein the electrodes have localized areas exposed to the liquid distributed in such a pattern of locations that an edge of each vane sweeps past said areas successively.
Claim 12
Dependent Claim
50 words
A liquid-flow sensor as in claim 1 wherein said electrodes have localized areas exposed to the liquid and are distributed so that an edge of each said vane comes simultaneously opposite two of said areas and opposite the third area at a different time in the rotation of the rotor.
Claim 13
Independent Claim
96 words
The method of sensing the flow of liquid including the steps of exposing areas of at least two electrodes to the liquid and electrically energizing said two electrodes to develop a pattern of current paths through a volume of the liquid, disposing a vaned rotor in the liquid to be rotated by the flow thereof and thereby operate the vanes past said two electrodes successively into positions wherein a substantial portion of said current paths would extend through the thickness of a vane but are suppressed thereby and into positions clear of such substantial current paths.
Claim 14
Independent Claim
96 words
The method of sensing the flow of liquid including the steps of exposing areas of at least two electrodes to the liquid and electrically energizing said two electrodes to develop a pattern of current paths through a volume of the liquid, disposing a vaned rotor in the liquid to be rotated by the flow thereof and thereby operate the vanes past said two electrodes successively into positions wherein a substantial portion of said current paths would extend through the thickness of a vane but are suppressed thereby and into positions clear of such substantial current paths.
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) | 1985-06-07 | 1985-12-07 | 1986-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-07 | 1989-12-07 | 1990-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-07 | 1993-12-07 | 1994-06-08 | $7700.00 | Window Closed / Lapsed |