EP0076392A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Bridge for reactive detector circuit
Assignee: Combustion Engineering Inc
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Filing: 1982-09-06
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Granted: —
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Expires: 2002-09-06
Abstract
Abstract An improved transducer bridge circuit in a pressure gauge having reactive transducer elements such as inductance coils (18,18'). The electrical bridge includes first and second legs (28,30) each having a fixed resistor (22,22') in series with a coil (18,18'). The first and second legs (28,30) are connected in parallel whereby a resistor junction (24) and a coil junction (26) are formed at the extremities of the legs. A voltage oscillator (20) is connected to the resistor junction (24), and means (32) for maintaining a constant voltage are connected to the coil junction (26). A differential amplifier (36) is connected (A,B) to each leg between the fixed resistor (22,22') and the coil (18,18') such that the differential change in coil reluctances due to pressure variations, is amplified and manifested in a readout unit (34). This bridge is particularly advantageous when the oscillator (20) and electronic processing components (22,36,34) are to be located remotely, such as outside a nuclear containment building (10), relative to the sensing coils (18).
Inventors
- 👤 John Scott Dietrich
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 06:46
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/10; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/20; G01L9/0041; G01L9/007; G01R; G01R17/00; G01R17/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
175 words
In a fluid pressure detector having reactive transducer elements and means adapted to connect to a readout unit, an improved transducer bridge circuit comprising: a first leg having a fixed resistor in series with a reactive element; a second leg having a fixed resistor and reactive element in the same series order as said first leg, said first and second legs connected in parallel whereby a resistor junction and a reactive element junction are formed at the extremities of the legs; a voltage oscillator connected to the resistor junction; means for maintaining a constant voltage at the reactive element junction; means for differentially varying the reactance of the reactive elements in response to a change in the fluid pressure to be detected; and a differential amplifier connected between the fixed resistor and the reactive element on each leg, the amplifier being adapted to input to the readout circuit, whereby a differential change in the reactances of said reactive elements is manifested in the readout unit, and any noise common to both legs is not amplified.
Claim 2
Dependent Claim
175 words
In a fluid pressure detector having reactive transducer elements and means adapted to connect to a readout unit, an improved transducer bridge circuit comprising: a first leg having a fixed resistor in series with a reactive element; a second leg having a fixed resistor and reactive element in the same series order as said first leg, said first and second legs connected in parallel whereby a resistor junction and a reactive element junction are formed at the extremities of the legs; a voltage oscillator connected to the resistor junction; means for maintaining a constant voltage at the reactive element junction; means for differentially varying the reactance of the reactive elements in response to a change in the fluid pressure to be detected; and a differential amplifier connected between the fixed resistor and the reactive element on each leg, the amplifier being adapted to input to the readout circuit, whereby a differential change in the reactances of said reactive elements is manifested in the readout unit, and any noise common to both legs is not amplified.
Claim 3
Dependent Claim
14 words
The improved transducer bridge of Claim 1, wherein the reactance elements are inductance coils.
Claim 4
Dependent Claim
21 words
The improved transducer bridge of Claim 2, wherein the oscillator frequency is in the range of about 100 to 2000 hz.
Claim 5
Dependent Claim
23 words
The improved transducer bridge of Claim 3, wherein the waveform generated by the oscillator is sinusoidal with an amplitude of about 5 volts.
Claim 6
Dependent Claim
38 words
The improved transducer bridge of Claims 1 or 4, wherein the respective portions of each leg between the reactance elements and the differential amplifier connections have substantially the same electrical length and are electrically insulated from each other.
Claim 7
Dependent Claim
27 words
The improved transducer bridge of Claim 5 wherein the distance between the reactive element and the amplifier connection on each leg is at least about 250 feet.
Claim 8
Dependent Claim
30 words
The improved transducer bridge of Claim 6, wherein the portion of each leg between the connection of the amplifier, and the reactive elements, is contained in a shielded, twisted cable.
Claim 9
Dependent Claim
26 words
The improved transducer bridge of Claim 1 wherein each of said legs is of substantially the same electrical length and is electrically insulated from the other.
Claim 10
Dependent Claim
153 words
A transducer unit for the detection of a fluid pressure in a nuclear power plant having a containment building comprising: magnetically permeable means for deforming in response to changes in the fluid pressure; a pair of inductance coils disposed about and magnetically coupled to said permeable means; a fixed resistor in series with each of the coils, whereby two legs are formed, each having a resistor and coil in series; a resistor junction joining the ends of the leqs closest to the resistors and a coil junction joining the ends of the legs closest to the coils, whereby the two legs are joined electrically parallelly; means for generating an oscillating electrical signal at the resistor junction; means for maintaining a constant voltage at the coil junction; and a differential amplifier connected between the resistor and coi on each leg, and having means thereon for delivering the amplified differential signal to an output circuit.
Claim 11
Dependent Claim
153 words
A transducer unit for the detection of a fluid pressure in a nuclear power plant having a containment building comprising: magnetically permeable means for deforming in response to changes in the fluid pressure; a pair of inductance coils disposed about and magnetically coupled to said permeable means; a fixed resistor in series with each of the coils, whereby two legs are formed, each having a resistor and coil in series; a resistor junction joining the ends of the leqs closest to the resistors and a coil junction joining the ends of the legs closest to the coils, whereby the two legs are joined electrically parallelly; means for generating an oscillating electrical signal at the resistor junction; means for maintaining a constant voltage at the coil junction; and a differential amplifier connected between the resistor and coi on each leg, and having means thereon for delivering the amplified differential signal to an output circuit.
Claim 12
Dependent Claim
41 words
The transducer unit of Claim 9 wherein the magnetically permeable means and the coils are within the containment building, and the resistors, means for generating an oscillating signal, and differential amplifier connection to the legs are all outside the containment building.
Claim 13
Dependent Claim
32 words
The transducer unit of Claim 10 wherein the respective portions of each leg between the coil and the amplifier connections have the same electrical length and are electrically insulated from each other.
References Cited (Backward Citations)
CH317936A
Cited
WO1980001951A1
Cited
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