Plate array for moisture sensor with reduced sensitivity to loading effects
AssigneeWagner Electronic Products, Inc.
InventorEdward Duane Wagner
Life of this patent
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Abstract
A plate array for moisture sensors has a transmitter electrode and a detector electrode interposed between portions of a phase electrode. The transmitter and phase electrodes are driven with alternating current signals having a one hundred and eighty degree phase difference so as to induce a signal at the detector electrode relating to a moisture content of a material in the electrical fields which has a reduced sensitivity to electrically loading the material, such as from contact with a hand or steel roller.
Claims10
A plate array for a moisture content sensor, comprising:
- a substrate;
- a transmitter electrode supported on the substrate and producing an electrical field in a surrounding space when driven by an alternating current transmitter signal;
- a detector electrode supported on the substrate next to the transmitter electrode such that a signal related to a moisture content of a material placed in the electrical field is induced in the detector electrode;
- a phase electrode having a first portion and a second portion supported on the substrate and having the transmitter electrode and the detector electrode interposed between the portions of the phase electrode,
- whereby driving the phase electrode with a phase signal that is substantially one hundred and eighty degrees out of phase with the transmitter signal reduces the effects of electrically loading the material on the moisture-related signal.
A plate array for a moisture content sensor, comprising:
- first and second opposed substrates having a space between for passing a material having a moisture content which is to be sensed;
- first and second detector electrodes formed one on each of the substrates;
- first and second transmitter electrodes formed one on each of the substrates;
- first and second phase electrodes formed one on each of the substrates and each having first and second portions to either side of the detector electrode and the transmitter electrode on the substrates;
- the transmitter electrodes on the substrates producing an electrical field in the space between the substrates when driven with an alternating current transmitter signal and causing a signal related to the moisture content of the material to be received at the detector electrodes;
- and
- the phase electrodes limiting the electrical field to the space bounded at one end by the first portions of the phase electrodes and at another end by the second portions of the phase electrodes when the phase electrodes are driven with an alternating current phase signal which is approximately one hundred and eighty degrees out of phase with the transmitter signal.
A method of configuring a plate array for a moisture sensor to have reduced sensitivity to electrical loading, comprising:
- positioning a transmitter electrode adjacent to a detector electrode such that a detector signal related to the moisture content of a material passed through an electrical field generated by applying an alternating current transmitter signal to the transmitter electrode is induced in the detector electrode;
- interposing the transmitter electrode and the detector electrode between two portions of a phase electrode such that driving the phase electrode with an alternating current phase signal which is substantially one hundred and eighty degrees out of phase with the transmitter signal reduces the effect on the detector signal of electrically loading the material outside a space bounded at two ends by the portions of the phase electrode.
Dependencies are inferred from the claim text.