US3846771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Position indication system
Assignee: Westinghouse Electric Corp
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Filing: 1973-01-03
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Granted: 1974-11-05
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Expires: 1993-01-03
Abstract
Abstract A position indication system is described for detecting the relative position of a control rod within the core of a nuclear reactor. The basic sensor of this system is formed from a plurality of discrete electrical coils individually wound around the rod travel housing in a tandem array extend longitudinally along the control rod drive shaft''s axis of movement. An AC current is established within each of the respective coils at a sufficiently low frequency to enable the resulting flux to penetrate the rod travel housing. A change in impedance within the individual coils is monitored as the control rod drive shaft moves past the centers of the coil locations. This change in impedance is translated to discrete electrical outputs indicative of the relative location of the control rod within the core of the nuclear reactor. In one embodiment, the respective coils are connected in series with corresponding resistors and the corresponding common node points of adjacent coil-resistor series combinations are used as inputs to a differential amplifier which provides an output representative of the voltage difference between corresponding nodes. The differential amplifier''s output is then translated to a digital indication of control rod position. Alternate embodiments are presented describing a multiplicity of digital outputs which can be provided in accordance with this invention.
Inventors
- 👤 D Boomgaard
- 👤 F Young
- 👤 F Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:03
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/20; G01D5/2006; G01D5/2013
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
116 words
A position indication system for detecting the location of an elongated, longitudinally movable, metallic member having one degree of freedom along an axis corresponding to its longitudinal dimension comprising: a plurality of discrete electrical coils wound around the circumferential periphery of the axis of movement of the movable member and arranged in tandem longitudinally therealong; an alternating current source electrically coupled to each of said plurality of coils; and means for respectively detecting a change in impedance within each of said plurality of coils as the movable member moves along its axis of movement, said detection means providing discrete outputs indicative of the location of the movable member relative to said tandem arrangement of discrete coils.
Claim 2
Dependent Claim
116 words
A position indication system for detecting the location of an elongated, longitudinally movable, metallic member having one degree of freedom along an axis corresponding to its longitudinal dimension comprising: a plurality of discrete electrical coils wound around the circumferential periphery of the axis of movement of the movable member and arranged in tandem longitudinally therealong; an alternating current source electrically coupled to each of said plurality of coils; and means for respectively detecting a change in impedance within each of said plurality of coils as the movable member moves along its axis of movement, said detection means providing discrete outputs indicative of the location of the movable member relative to said tandem arrangement of discrete coils.
Claim 3
Dependent Claim
54 words
The position indication system of claim 1 wherein the movable member has an elongated dimension approximately equal to the longitudinal dimension of said tandem arrangement of discrete coils and the movaBle member appears substantially within the center of each of said plurality of discrete coils, concurrently, at at least one point in travel thereof.
Claim 4
Dependent Claim
52 words
The position indication system of claim 1 wherein said plurality of coils are connected in parallel to said alternating current source which is arranged to have a substantially constant voltage output and said means for measuring the respective impedance change within said plurality of coils comprises means for measuring the current therethrough.
Claim 5
Dependent Claim
44 words
The position indication system of claim 1 wherein said means for detecting an impedance change within said plurality of discrete coils is responsive thereto to provide a digital output indicative of the location of the movable member relative to said tandem arrangement of coils.
Claim 6
Dependent Claim
61 words
The position indication system of claim 4 wherein each of said plurality of coils is connected in series with a corresponding resistor and each of said respective coil-resistor series combinations is connected in parallel to said alternating current source and wherein said means for detecting an impedance change monitors circuit parameters at the respective tie points of the corresponding coil-resistor combinations.
Claim 7
Dependent Claim
107 words
The position indication system of claim 5 wherein said means for detecting an impedance change comprises a plurality of differential circuit means having separate inputs respectively connected between the tie points of corresponding coil-resistor series combinations lying adjacent along the tandem array of said plurality of coils, said differential circuit means being responsive to the voltage differential appearing across the separate inputs to provide an output indicative thereof, the respective outputs of said plurality of differential circuit means are connected to corresponding readout means responsive to the differential output to provide an indication of the relative position of the movable member with respect to said coil locations.
Claim 8
Dependent Claim
15 words
The position indication system of claim 6 wherein said differential circuit means comprises differential amplifiers.
Claim 9
Dependent Claim
15 words
The position indication system of claim 6 wherein said differential circuit means comprises differential transformers.
Claim 10
Dependent Claim
44 words
The position indication system of claim 5 wherein at least two of said plurality of coils lying adjacent along the tandem array are connected in parallel and said parallel coil combination is connected to said corresponding series resistor to form said coil-resistor series combination.
Claim 11
Dependent Claim
25 words
The position indication system of claim 1 wherein said movable member is a reactor drive rod forming part of a nuclear reactor control rod assembly.
Claim 12
Dependent Claim
15 words
The position indication of claim 1 wherein said metallic member is constructed from ferromagnetic material.
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) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |