US4823071A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitive measuring system for measuring the distance between two relatively movable parts
Assignee: MOTOREN-UND TURBINEN-UNION MUNCHEN GMBHM POSTFACH 50 064 DACHAUER STRASSE 665 8000 MUNCHEN 50 WEST GERMANY (HEREAFTER MTU)
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Filing: 1985-09-06
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Granted: 1989-04-18
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Expires: 2005-09-06
Abstract
Abstract A capacitive measuring system for measuring the distance between two relatively movable parts based on measurement of capacitative charge comprising a measuring sensor which forms one plate of the capacitor whose gap is to be measured. With the position of the sensor face in the fixed part of casing being known, the plate distance of the gap capacitor provides a direct measure of the gap.
Inventors
- 👤 Kurt Ding
- 👤 Hartwig Knoell
- 👤 Josef Wenzl
- 👤 Hermann Biebl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:30
CPC Classifications
F; F01; F01D; F01D21/00; F01D21/04; G; G01; G01B; G01B7/00; G01B7/14
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
209 words
A capacitive measuring system based on charge measurement for measuring the distance between two relatively movable parts, said system comprising: a sensor coupled to one of the two relatively movable parts and facing the other of the two parts; means for biassing the sensor and said other part to a variable bias voltage (U ref ) which is stabilized by a voltage supply unit to form a measuring capacitor in which one of the plates of the capacitor is constituted by said sensor and the other of the plates of the capacitor is constituted by said other part; means for measuring charge of said capacitor at two reference potentials; a charge amplifier connected to said sensor, said charge amplifier and voltage supply unit being arranged at a distance from said sensor; a triaxial cable connecting said sensor to said charge amplifier and said voltage supply unit; said charge amplifier having a bad width attuned to the frequency of the expected charge signal produced by said capacitor; said sensor having a measuring face which faces said other part with a gap d therebetween; and means for determining gap capacitance C s from measured charge quantity Q of said capacitor at said two reference potentials from the relation C=Q/U ref .
Claim 2
Dependent Claim
209 words
A capacitive measuring system based on charge measurement for measuring the distance between two relatively movable parts, said system comprising: a sensor coupled to one of the two relatively movable parts and facing the other of the two parts; means for biassing the sensor and said other part to a variable bias voltage (U ref ) which is stabilized by a voltage supply unit to form a measuring capacitor in which one of the plates of the capacitor is constituted by said sensor and the other of the plates of the capacitor is constituted by said other part; means for measuring charge of said capacitor at two reference potentials; a charge amplifier connected to said sensor, said charge amplifier and voltage supply unit being arranged at a distance from said sensor; a triaxial cable connecting said sensor to said charge amplifier and said voltage supply unit; said charge amplifier having a bad width attuned to the frequency of the expected charge signal produced by said capacitor; said sensor having a measuring face which faces said other part with a gap d therebetween; and means for determining gap capacitance C s from measured charge quantity Q of said capacitor at said two reference potentials from the relation C=Q/U ref .
Claim 3
Dependent Claim
27 words
A measuring system as claimed in claim 1 wherein said one part is a stationary casing and said other part is a rotor having spaced blades thereon.
Claim 4
Dependent Claim
32 words
A measuring system as claimed in claim 2 wherein said measuring face of said sensor is smaller in extent than the spacing between two adjacent blades at the periphery of the blades.
Claim 5
Dependent Claim
24 words
A measuring system as claimed in claim 2 wherein said sensor is fixedly securable in said casing and permits of displacement calibration in situ.
Claim 6
Dependent Claim
24 words
A measuring system as claimed in claim 1 wherein the polarity of the voltage output from the charge amplifier to the capacitor is reversible.
Claim 7
Dependent Claim
15 words
A measuring system as claimed in claim 5 comprising means for automatically effecting the reversal.
Claim 8
Dependent Claim
31 words
A measuring system as claimed in claim 1 wherein said system includes multiple channels for recording and evaluating capacitance values of said sensor and a computer for receiving said capacitance values.
Claim 9
Dependent Claim
23 words
A measuring system as claimed in claim 1 wherein said voltage supply unit includes means for controlling the bias voltage (U ref ).
Claim 10
Dependent Claim
27 words
A measuring system as claimed in claim 8 wherein said charge amplifier and said means for controlling the bias voltage are formed into a common constructional unit.
Claim 11
Dependent Claim
44 words
A measuring system as claimed in claim 1 wherein said triaxial cable includes an inner conductor connected to one pole of the amplifier, an outer conductor connected to the other pole of the amplifier and an insulator layer between said inner and outer conductors.
Claim 12
Dependent Claim
33 words
A measuring system as claimed in claim 1 wherein said means for measuring charge of the capacitor measures the charge at the two reference potentials at different polarities of the sensor bias voltage.
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) | 1992-04-17 | 1992-10-17 | 1993-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-17 | 1996-10-17 | 1997-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-17 | 2000-10-17 | 2001-04-18 | $7700.00 | Window Closed / Lapsed |