US3717031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three electrode flow meter
Assignee: University of California
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Filing: 1971-02-22
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Granted: 1973-02-20
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Expires: 1991-02-22
Abstract
Abstract An improved electromagnetic flow meter is provided which includes means for nulling out the transformer or quadrature electromotive force which is independent of fluid flow and which is in quadrature phase with the useful flow signal. This nulling is achieved by juxtaposing to one of the electrodes of the flow meter a pair of electrodes (instead of a single electrode as is standard practice). This electrode pair is connected to the end points of an external potentiometer, and the wiper is connected to one of the amplifier input terminals. By adjusting the wiper position, a zero signal may be obtained from the amplifier at zero flow. External circuitry may also be provided for a manual or servo controlled fine adjustment of the quadrature electromotive force compensation.
Inventors
- 👤 J Biscar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:20
CPC Classifications
G; G01; G01F; G01F1/00; G01F1/56; G01F1/58; A; A61; A61B; A61B5/00; A61B5/02; A61B5/026; A61B5/0265; A61B5/027
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
182 words
A self-compensating sensor for an electromagnetic flow meter to be located in a conduit to measure fluid flow therein; comprising: frame means locatable in said conduit; a common electrode mounted on one side of said frame means; a pair of electrodes mounted on the other side of said frame means across said conduit from said common electrode; external circuit means including a first conductor extending around said frame to said common electrode and connected thereto, a pair of conductors extending around said frame to respective ones of said pair of electrodes and respectively connected thereto, a balancing potentiometer connected across said pair of conductors, and signal mixer means connected between said first conductor and a movable tap on said potentiometer, whereby said sensor develops a flow signal between each of said pair of electrodes and said common electrode which is sensed by said signal mixer means, and also develops a pair of oppositely phased electromotive forces between said common electrode and respective ones of said pair of electrodes which are balanced out by adjustment of said movable tap on said balancing potentiometer.
Claim 2
Dependent Claim
182 words
A self-compensating sensor for an electromagnetic flow meter to be located in a conduit to measure fluid flow therein; comprising: frame means locatable in said conduit; a common electrode mounted on one side of said frame means; a pair of electrodes mounted on the other side of said frame means across said conduit from said common electrode; external circuit means including a first conductor extending around said frame to said common electrode and connected thereto, a pair of conductors extending around said frame to respective ones of said pair of electrodes and respectively connected thereto, a balancing potentiometer connected across said pair of conductors, and signal mixer means connected between said first conductor and a movable tap on said potentiometer, whereby said sensor develops a flow signal between each of said pair of electrodes and said common electrode which is sensed by said signal mixer means, and also develops a pair of oppositely phased electromotive forces between said common electrode and respective ones of said pair of electrodes which are balanced out by adjustment of said movable tap on said balancing potentiometer.
Claim 3
Dependent Claim
182 words
A self-compensating sensor for an electromagnetic flow meter to be located in a conduit to measure fluid flow therein; comprising: frame means locatable in said conduit; a common electrode mounted on one side of said frame means; a pair of electrodes mounted on the other side of said frame means across said conduit from said common electrode; external circuit means including a first conductor extending around said frame to said common electrode and connected thereto, a pair of conductors extending around said frame to respective ones of said pair of electrodes and respectively connected thereto, a balancing potentiometer connected across said pair of conductors, and signal mixer means connected between said first conductor and a movable tap on said potentiometer, whereby said sensor develops a flow signal between each of said pair of electrodes and said common electrode which is sensed by said signal mixer means, and also develops a pair of oppositely phased electromotive forces between said common electrode and respective ones of said pair of electrodes which are balanced out by adjustment of said movable tap on said balancing potentiometer.
Claim 4
Dependent Claim
182 words
A self-compensating sensor for an electromagnetic flow meter to be located in a conduit to measure fluid flow therein; comprising: frame means locatable in said conduit; a common electrode mounted on one side of said frame means; a pair of electrodes mounted on the other side of said frame means across said conduit from said common electrode; external circuit means including a first conductor extending around said frame to said common electrode and connected thereto, a pair of conductors extending around said frame to respective ones of said pair of electrodes and respectively connected thereto, a balancing potentiometer connected across said pair of conductors, and signal mixer means connected between said first conductor and a movable tap on said potentiometer, whereby said sensor develops a flow signal between each of said pair of electrodes and said common electrode which is sensed by said signal mixer means, and also develops a pair of oppositely phased electromotive forces between said common electrode and respective ones of said pair of electrodes which are balanced out by adjustment of said movable tap on said balancing potentiometer.
Claim 5
Dependent Claim
15 words
The combination defined in claim 1, in which said signal mixer means comprises a resistor.
Claim 6
Dependent Claim
15 words
The combination defined in claim 1, in which said signal mixer means comprises a transformer.
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) | 1976-02-20 | 1976-08-21 | 1977-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-20 | 1980-08-21 | 1981-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-20 | 1984-08-21 | 1985-02-20 | $7700.00 | Window Closed / Lapsed |