Moisture-content-measuring system employing a separate bridge circuit for each sensing electrode thereof

Claim 3

The system as defined in claim 1 including a second pair of sensing electrodes having third and fourth electrodes positioned opposite each other and respectively adjacent said first and second electrodes; second signal means producing a second alternating signal which is l80* out of phase relative to said first signal, means coupling said second alternating signal to each of said third and fourth electrodes so that the potential thereof at any instant has the same magnitude and polarity; and said monitoring Means further including third and fourth capacitance bridge circuits, each including a plurality of legs, means connecting said third electrode in one leg of said third capacitance bridge circuit, means connecting said fourth electrode in one leg of said fourth capacitance bridge circuit, means positioning said third capacitance bridge circuit adjacent said third electrode, and means positioning said fourth capacitance bridge circuit adjacent said fourth electrode.

Claim 4

The system as defined in claim 2 including first, second, third and fourth shield electrode means, means situating each of said shield electrode means respectively adjacent to and partially enclosing one of said first, second, third and fourth electrodes; and means connected to each of said shield electrode means for supporting a different one of said bridge circuits.

Claim 5

The system of claim 3 wherein each of said supporting means maintains its bridge circuit between its shield electrode and its sensing electrode.

Claim 6

The system of claim 2 wherein each of said bridge circuits includes a signal-rectifying circuit coupled to the legs thereof for providing unidirectional output signals from the associated bridge circuit.

Claim 7

The system of claim 5 including amplifier means coupled with said first and second bridge circuits for adding the output signals therefrom, and second amplifier means coupled with said third and fourth bridge circuits for adding the output signals therefrom.

Claim 8

The system of claim 3 wherein said situating means comprises a plurality of insulating members supporting said sensing electrodes inside said shield electrode means, and wherein each of said bridge circuits is positioned inside a different one of said insulating members.

Claim 9

A moisture-sensing system comprising in combination; first and second pairs of sensing electrodes, said first pair including first and second electrodes and said second pair including third and fourth electrodes, said first and third electrodes being maintained adjacent each other and disposed opposite said second and fourth electrodes to define a space for the positioning of material between the first and second and between the third and fourth electrodes; first, second, third and fourth capacitance bridge circuits each including a plurality of legs, means connecting said first, second, third and fourth electrodes in one leg, respectively, of said first, second, third and fourth capacitance bridge circuits, means positioning said first, second, third and fourth capacitance bridge circuits adjacent, respectively, said first, second, third and fourth electrodes, each of said capacitance bridge circuits providing an output signal when energized, which output signals are dependent on the moisture content of the material located in said space; signal means providing first and second alternating signals which are 180* out of phase with respect to each other; means coupling said first signal to said first and second electrodes and said second signal to said third and fourth electrodes; first amplifier means coupled with said first and second bridge circuits for providing output signals proportional to the sum of the output signals from said first and second bridge circuits; and second amplifier means coupled with said third and fourth bridge circuits and providing output signals proportional to the sum of the output signals from said third and fourth bridge circuits.

Claim 10

A moisture-sensing system comprising in combination; first and second pairs of sensing electrodes, said first pair including first and second electrodes and said second pair including third and fourth electrodes, said first and third electrodes being maintained adjacent each other and disposed opposite said second and fourth electrodes to define a space for the positioning of material between the first and second and between the third and fourth electrodes; first, second, third and fourth capacitance bridge circuits each including a plurality of legs, means connecting said first, second, third and fourth electrodes in one leg, respectively, of said first, second, third and fourth capacitance bridge circuits, means positioning said first, second, third and fourth capacitance bridge circuits adjacent, respectively, said first, second, third and fourth electrodes, each of said capacitance bridge circuits providing an output signal when energized, which output signals are dependent on the moisture content of the material located in said space; signal means providing first and second alternating signals which are 180* out of phase with respect to each other; means coupling said first signal to said first and second electrodes and said second signal to said third and fourth electrodes; first amplifier means coupled with said first and second bridge circuits for providing output signals proportional to the sum of the output signals from said first and second bridge circuits; and second amplifier means coupled with said third and fourth bridge circuits and providing output signals proportional to the sum of the output signals from said third and fourth bridge circuits.

Claim 11

A moisture sensing system as defined in claim 8 including a plurality of shield electrodes, means positioning each of said shield electrodes adjacent to and partially enclosing one of said sensing electrodes, and means connected to each of said shield electrodes supporting one of said capacitance of bridge circuits between said shield electrode and its sensing electrode each of said bridge circuits is physically located inside a different one of said shield electrodes. 10 A moisture-sensing system as defined in claim 9 wherein said supporting means includes electrical insulatIon means supporting each of said sensing electrodes inside a different one of said shield electrodes, and wherein each of said bridge circuits is located inside one of the insulating members which supports the associated sensing electrode.