US3832618A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic differential pressure transmitter
Assignee: Fischer and Porter Co
•
Filing: 1973-01-29
•
Granted: 1974-08-27
•
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 04:11
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.
References Cited (Backward Citations)
US2634747A
Cited
US2847625A
Cited
US2980835A
Cited
US3342072A
Cited
US3660745A
Cited
US3564923A
Cited
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 |