Patent US5753975A successfully refreshed from Google Patents.
Patent US3832618A successfully refreshed from Google Patents.
US3832618A
Expired / Lapsed
US
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Electronic differential pressure transmitter
Assignee: Fischer and Porter Co
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Filing: 1973-01-29
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Granted: 1974-08-27
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Expires: 1993-01-29
Abstract
Abstract An electronic differential pressure transmitter for use with industrial processes to produce an output signal suitable for transmission to a remote station for operating, indicating, recording or control equipment. The transmitter includes a force bar to which an input force is applied, the resultant bar displacement being sensed by a detector coupled to an electronic circuit yielding a feedback signal proportional to the input force. The feedback signal is fed to a motor that applies to the bar a rebalancing force in opposition to the input force. Adjustment in the span of the instrument is effected electronically by a circuit in which the feedback signal is split between the motor and a shunt path to an extent affording the desired span.
Inventors
- 👤 P Levesque
- 👤 M Gaertner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:09
CPC Classifications
G; G01; G01L; G01L11/00; G01L11/004; G01L11/008; G01L13/00; G01L13/02; G01L13/025; G01L9/00; G01L9/0041; G01L9/0072; G01L9/12
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
161 words
A differential pressure transmitter comprising: A. a pivoted force bar; B. means to apply an input force to said force bar to effect displacement thereof from a balanced position; C. a detector mechanically coupled to said bar to produce an electrical value which varies as a function of said displacement; D. an electronic circuit coupled to said detector to produce an output signal proportional to said displacement; E. an electrical force motor mechanically coupled to said force bar to apply a force thereto in opposition to said input force to rebalance said bar; and F. means including a current-splitter circuit to apply said output signal to said motor to energize same, and to a shunt path in a ratio adjusting the transmitter to a desired span, said shunt path being constituted by a transistor and means to vary the conductivity of said transistor as a function of the current passing through said motor without regard to the resistance of the motor.
Claim 2
Dependent Claim
161 words
A differential pressure transmitter comprising: A. a pivoted force bar; B. means to apply an input force to said force bar to effect displacement thereof from a balanced position; C. a detector mechanically coupled to said bar to produce an electrical value which varies as a function of said displacement; D. an electronic circuit coupled to said detector to produce an output signal proportional to said displacement; E. an electrical force motor mechanically coupled to said force bar to apply a force thereto in opposition to said input force to rebalance said bar; and F. means including a current-splitter circuit to apply said output signal to said motor to energize same, and to a shunt path in a ratio adjusting the transmitter to a desired span, said shunt path being constituted by a transistor and means to vary the conductivity of said transistor as a function of the current passing through said motor without regard to the resistance of the motor.
Claim 3
Dependent Claim
34 words
A transmitter as set forth in claim 1, wherein said input force is derived from a differential pressure capsule having low and high pressure diaphragms linked to the lowermost end of the force bar.
Claim 4
Dependent Claim
55 words
A transmitter as set forth in claim 2, wherein the upper end of said force bar is linked by a connecting rod to a force motor, and wherein said electrical force motor includes a motor arm whose fulcrum is a cross-flexure, and wherein said detector is connected by a detector arm to said force motor.
Claim 5
Dependent Claim
28 words
A transmitter as set forth in claim 3, wherein said motor is of the moving-coil type, the coil thereof being secured to one end of said motor arm.
Claim 6
Dependent Claim
28 words
A transmitter as set forth in claim 4, further including a counterweight on the other end of the motor arm, said counterweight being provided with adjustable balancing screws.
Claim 7
Dependent Claim
63 words
A transmitter as set forth in claim 1, wherein said detector is of the capacitance type and is formed by two spaced electrodes on one side of a dielectric plate and a movable armature on the other side of said plate to vary the effective gap between the electrodes, said armature being mounted on a ball swivel mechanically linked to said force motor.
Claim 8
Dependent Claim
42 words
A transmitter as set forth in claim 1, wherein said detector is of the capacitance type and said electronic circuit includes a free-running multivibrator coupled to said detector, the duty cycle of said multivibrator being indicative of the capacity of said detector.
Claim 9
Dependent Claim
16 words
A transmitter as set forth in claim 1, wherein said electronic circuit includes a voltage regulator.
Claim 10
Dependent Claim
16 words
A transmitter as set forth in claim 1, wherein said electronic circuit includes a current regulator.
Claim 11
Dependent Claim
28 words
A transmitter as set forth in claim 7, wherein the output of said multivibrator is applied to an integrator whose output is fed to a current-amplifying output stage.
Claim 12
Dependent Claim
58 words
A transmitter as set forth in claim 1, wherein said splitter circuit includes a transistor connected across said motor and forming said shunt path, an amplifier to control the conductivity of said transistor, and a span-adjusting potentiometer connected to said motor and to said amplifier to control the ratio of current passing through said path and said mOtor.
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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) | 1977-08-26 | 1978-02-25 | 1978-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-26 | 1982-02-25 | 1982-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-26 | 1986-02-25 | 1986-08-27 | $7700.00 | Window Closed / Lapsed |