Apparatus for detecting the presence of a liquid
First Claim
1. An apparatus for detecting the presence of a liquid in a region, said apparatus comprising:
- a first electrically conducting circuit;
a second electrically conducting circuit spaced apart from said first circuit and having a first terminal and an opposing, spaced-apart second terminal;
a switch for connecting said first and second terminals of said second circuit, said switch completing said second circuit when exposed to said liquid;
means electrically connected to said first circuit for generating a first alternating current having a first resonant frequency in said first circuit, said first alternating current inducing a second alternating current in said second circuit when said second circuit is placed in said region, said first circuit is brought close to said second circuit and said switch is closed, said second alternating current causing a change in said first resonant frequency of said first circuit to a second resonant frequency; and
means for indicating closure of said switch by exposure to said liquid, said indicating means indicating said change from said first resonant frequency to said second resonant frequency.
1 Assignment
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Accused Products
Abstract
An apparatus for detecting the presence of a liquid in a region, including an electrically passive sensor adapted for contacting the liquid, and an electrically active detector. The sensor is a circuit with a pair of spaced-apart terminals connected to a switch that closes in the presence of the liquid. The detector carries an alternating current with a resonant frequency. When the sensor is placed in a region and liquid is present in the region, the circuit of the sensor is closed. By bringing the detector close to the sensor, an alternating current is induced in the sensor that will, in turn, alter the resonant frequency of the detector. The change in the resonant frequency is signaled by a transducer. The switch can operate by a change in conductivity of a material between the terminals of the sensor or by expansion of a liquid absorber that pushes the two terminals together, or by a change in the conductivity of the space between the terminals as a result of the presence of the liquid. The detector generates an audible or visible signal, or both, in response to the change in current.
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Citations
18 Claims
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1. An apparatus for detecting the presence of a liquid in a region, said apparatus comprising:
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a first electrically conducting circuit; a second electrically conducting circuit spaced apart from said first circuit and having a first terminal and an opposing, spaced-apart second terminal; a switch for connecting said first and second terminals of said second circuit, said switch completing said second circuit when exposed to said liquid; means electrically connected to said first circuit for generating a first alternating current having a first resonant frequency in said first circuit, said first alternating current inducing a second alternating current in said second circuit when said second circuit is placed in said region, said first circuit is brought close to said second circuit and said switch is closed, said second alternating current causing a change in said first resonant frequency of said first circuit to a second resonant frequency; and means for indicating closure of said switch by exposure to said liquid, said indicating means indicating said change from said first resonant frequency to said second resonant frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for detecting the presence of a liquid in a region, said apparatus comprising:
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a first electrically conducting coil; a second electrically conducting coil spaced apart from said first coil and having a first terminal and an opposing, spaced apart second terminal; a switch for connecting said first and second terminals of said second coil, said switch completing said second coil when closed by exposure to said liquid; means electrically connected to said first coil for generating a first alternating current having a first resonant frequency in said first coil, said first alternating current inducing a second alternating current in said second coil when said second coil is placed in said region, said first coil is brought proximate to said second coil and said switch is closed by said liquid, said induction of said second alternating current causing a change in said first resonant frequency of said first coil to a second resonant frequency; and a transducer responsive to said change from said first resonant frequency to said second resonant frequency to indicate closure of said switch by the presence of said liquid. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification