Digital rod position detector system
First Claim
1. Apparatus for detecting the location of an end of an elongated, longitudinally movable member, comprising:
- a plurality of spaced, discrete electrical coils through which said elongated member passes sequentially in moving longitudinally and in so doing, varies the inductance of each coil as it passes therethrough;
means connecting said plurality of coils in sets with each set including first and second groups of equal numbers of said coils connected in parallel, with the two groups of coils connected in series at a common node, with none of the coils in any given set being adjacent to any other coil in the set, and with the number of sets equal at least to the number of coils in a set;
a pair of impedances connected in series at a common node;
an alternating current source connected across said sets of coils and said pair of impedances; and
output signal generating means connected between the common node of said pair of impedances and the common nodes of each of said sets of coils with the ratio of the impedances of the pair of impedances being the same as the ratio of the impedance of each coil in the first group to the impedance of each coil in the second group of each set, said output signal generating means being responsive to the successive change in impedance in each coil resulting from penetration of the coil by the end of said elongated member to generate output signals representative of the position of the end of said elongated member relative to said coils.
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Accused Products
Abstract
Coils placed at spaced locations along the path of an axially movable magnetically permeable and/or electrically conductive rod, which changes the impedance of each coil as it passes through, are connected in sets with each set comprising two series connected groups of equal numbers of parallel connected, non-adjacent coils energized by an a-c source. The voltage at the common node of each set of coils, which fluctuates as equal and unequal numbers of coils in the two groups in a given set are penetrated by the end of the rod, is compared with the voltage at the common node of a pair of series connected resistors, also energized by the a-c source, to generate one digit of an unambiguous, multi-digit, digital rod position signal. Since only one signal wire to the remote electronics is required for each set of coils, and since they only carry a voltage signal, the required wiring is minimized. Compensation is provided to maintain the location of the rod end relative to each coil at which the digital signal changes state despite variations in temperature and voltage.
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Citations
15 Claims
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1. Apparatus for detecting the location of an end of an elongated, longitudinally movable member, comprising:
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a plurality of spaced, discrete electrical coils through which said elongated member passes sequentially in moving longitudinally and in so doing, varies the inductance of each coil as it passes therethrough; means connecting said plurality of coils in sets with each set including first and second groups of equal numbers of said coils connected in parallel, with the two groups of coils connected in series at a common node, with none of the coils in any given set being adjacent to any other coil in the set, and with the number of sets equal at least to the number of coils in a set; a pair of impedances connected in series at a common node; an alternating current source connected across said sets of coils and said pair of impedances; and output signal generating means connected between the common node of said pair of impedances and the common nodes of each of said sets of coils with the ratio of the impedances of the pair of impedances being the same as the ratio of the impedance of each coil in the first group to the impedance of each coil in the second group of each set, said output signal generating means being responsive to the successive change in impedance in each coil resulting from penetration of the coil by the end of said elongated member to generate output signals representative of the position of the end of said elongated member relative to said coils. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Apparatus for detecting the location of a free end of a rod axially insertable into a core of a nuclear reactor, comprising:
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a plurality of electrical coils of substantially equal electrical value spaced along the axially extending path followed by said free end of the rod; means connecting pairs of non-adjacent coils in series at a common node; a pair of substantially matched resistors connected in series at a common node; an alternating current source connected across said pairs of coils and across said pair of resistors; and output signal generating means connected to the common node between said pair of resistors and to each of the common nodes between the pairs of coils and responsive to electrical parameters at said nodes as affected by the successive pentration of said coils by said free end of the rod to generate discrete digital output signals representative of the location relative to the coils of the free end of the rod. - View Dependent Claims (13, 14, 15)
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Specification