US4357834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Displacement converter
Assignee: Yokogawa Electric Corp
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Filing: 1980-09-03
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Granted: 1982-11-09
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Expires: 2000-09-03
Abstract
Abstract A displacement converter useful for pressure gauges and similar instruments, the converter including a displacement detector provided with a variable capacitor responsive to the displacement to be metered and a fixed capacitor insensitive thereto. Also included is an amplitude-controllable oscillator whose AC output is applied to both capacitors, means being coupled to the capacitors to derive therefrom electrical signals which are a function of their capacitance values. These electrical signals are fed to a control circuit to produce a control signal corresponding to the difference therebetween, the control signal being applied to the oscillator to govern the output amplitude thereof in a manner maintaining the control signal at a constant value.
Inventors
- 👤 Atsushi Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:52
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/12; G01L9/0041; G01L9/0072
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
127 words
A displacement converter useful in pressure gauges and the like, the converter comprising: A. a displacement detector having a variable capacitor responsive to the displacement to be metered and a fixed capacitor insensitive thereto; B. an amplitude-controllable oscillator whose AC output is applied to both the variable and fixed capacitor; C. means coupled to the variable and fixed capacitors to derive therefrom first and second electrical signals which are a function of their respective capacitance values; D. a control circuit responsive to the first and second electrical signals to produce a control signal which depends on the difference therebetween; and E. means to apply said control signal to the oscillator to govern the output amplitude thereof in a manner maintaining the control signal at a constant level.
Claim 2
Dependent Claim
127 words
A displacement converter useful in pressure gauges and the like, the converter comprising: A. a displacement detector having a variable capacitor responsive to the displacement to be metered and a fixed capacitor insensitive thereto; B. an amplitude-controllable oscillator whose AC output is applied to both the variable and fixed capacitor; C. means coupled to the variable and fixed capacitors to derive therefrom first and second electrical signals which are a function of their respective capacitance values; D. a control circuit responsive to the first and second electrical signals to produce a control signal which depends on the difference therebetween; and E. means to apply said control signal to the oscillator to govern the output amplitude thereof in a manner maintaining the control signal at a constant level.
Claim 3
Dependent Claim
95 words
A converter as set forth in claim 1, wherein said detector includes a sensing diaphragm coupled to a movable electrode which is constituted by an annular plate whose periphery is attached by a resilient element to a metal ring concentric therewith, an insulation block disposed in parallel relation to said ring and said movable electrode, said insulation block having a first annular electrode thereon which faces said movable electrode to define said variable capacitor and a second annular electrode therein concentric with said first annular electrode and facing said ring to define said fixed electrode.
Claim 4
Dependent Claim
21 words
A converter as set forth in claim 2, wherein said first annular electrode has a marginal extension which faces said ring.
Claim 5
Dependent Claim
52 words
A displacement detector as set forth in claim 1, wherein said means coupled to said capacitors include a diode in series with a resistor connected to said variable capacitor to produce said first signal and a diode in series with a resistor connected to said fixed capacitor to produce said second signal.
Claim 6
Dependent Claim
18 words
A displacement converter as set forth in claim 4, further including a smoothing capacitor connected across each resistor.
Claim 7
Dependent Claim
28 words
A displacement converter as set forth in claim 5, wherein said control circuit includes an operational amplifier to whose input said first and said electrical signals are applied.
Claim 8
Dependent Claim
35 words
A displacement converter as set forth in claim 6, further including an amplifier coupled to the output of said operational amplifier to compare the output thereof with a reference voltage to produce said control signal.
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) | 1985-11-08 | 1986-05-10 | 1986-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-08 | 1990-05-10 | 1990-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-08 | 1994-05-10 | 1994-11-09 | $7700.00 | Window Closed / Lapsed |