US5765434A — Capacitive water height gauge and method

Claim 1

Independent Claim 99 words

In a gauge for monitoring the height of a body of water; a pair of electrically conductive plates disposed side-by-side to form a capacitor having a capacitance which is dependent upon the dielectric properties of materials in a region above the plates, means for positioning the plates beneath the body of water so that the capacitance is dependent upon the amount of water in the region above the plates, an oscillator which provides a signal having a frequency determined by the capacitance, and means for processing the oscillator signal to determine the height of the water above the plates.

Claim 2

Dependent Claim 99 words

In a gauge for monitoring the height of a body of water; a pair of electrically conductive plates disposed side-by-side to form a capacitor having a capacitance which is dependent upon the dielectric properties of materials in a region above the plates, means for positioning the plates beneath the body of water so that the capacitance is dependent upon the amount of water in the region above the plates, an oscillator which provides a signal having a frequency determined by the capacitance, and means for processing the oscillator signal to determine the height of the water above the plates.

Claim 3

Dependent Claim 53 words

The gauge of claim 1 wherein the means for processing the oscillator signal includes means for monitoring the frequency of the signal, a table of oscillator frequencies and corresponding water heights, and means for addressing the table in accordance with the frequency of the oscillator signal to determine the height of the water.

Claim 4

Dependent Claim 19 words

The gauge of claim 1 wherein the oscillator operates at frequencies on the order of 100 MHz and higher.

Claim 5

Dependent Claim 39 words

The gauge of claim 1 including a sensor for monitoring temperature of the water, and means responsive to the sensor for compensating for temperature dependent variations in the dielectric properties of water in determining the height of the water.

Claim 6

Dependent Claim 72 words

In a gauge for monitoring the height of a body of water: a generally planar substrate adapted to be positioned horizontally beneath the water, a pair of electrically conductive plates disposed side-by-side on one side of the substrate to form a capacitor having a capacitance which is dependent upon the amount of water above the plates, and means responsive to the capacitance for determining the height of the water above the plates.

Claim 7

Dependent Claim 72 words

In a gauge for monitoring the height of a body of water: a generally planar substrate adapted to be positioned horizontally beneath the water, a pair of electrically conductive plates disposed side-by-side on one side of the substrate to form a capacitor having a capacitance which is dependent upon the amount of water above the plates, and means responsive to the capacitance for determining the height of the water above the plates.

Claim 8

Dependent Claim 29 words

The gauge of claim 5 wherein the substrate is part of a printed circuit board, and the plates comprise areas of metal foil on one side of the substrate.

Claim 9

Dependent Claim 91 words

In a gauge for monitoring the height of a body of water: a generally planar substrate adapted to be positioned horizontally beneath the water, a pair of electrically conductive plates disposed side-by-side on one side of the substrate to form a capacitor having a capacitance which is dependent upon the amount of water above the plates, the plates being disposed concentrically of each other and including an inner sensor plate and an outer ground plate, and means responsive to the capacitance for determining the height of the water above the plates.

Claim 10

Dependent Claim 91 words

In a gauge for monitoring the height of a body of water: a generally planar substrate adapted to be positioned horizontally beneath the water, a pair of electrically conductive plates disposed side-by-side on one side of the substrate to form a capacitor having a capacitance which is dependent upon the amount of water above the plates, the plates being disposed concentrically of each other and including an inner sensor plate and an outer ground plate, and means responsive to the capacitance for determining the height of the water above the plates.

Claim 11

Dependent Claim 32 words

The gauge of claim 7 further including a guard plate disposed on the opposite side of the substrate in registration with the sensor plate for protecting the sensor plate from stray capacitances.

Claim 12

Dependent Claim 81 words

In a method of monitoring the height of a body of water: positioning a pair of electrically conductive plates side-by-side to form a capacitor having a capacitance which is dependent upon the dielectric properties of materials in a region above the plates, positioning the plates beneath the body of water so that the capacitance is dependent upon the amount of water in the region above the plates, and monitoring the capacitance to determine the height of the water above the plates.

Claim 13

Dependent Claim 81 words

In a method of monitoring the height of a body of water: positioning a pair of electrically conductive plates side-by-side to form a capacitor having a capacitance which is dependent upon the dielectric properties of materials in a region above the plates, positioning the plates beneath the body of water so that the capacitance is dependent upon the amount of water in the region above the plates, and monitoring the capacitance to determine the height of the water above the plates.

Claim 14

Dependent Claim 51 words

The method of claim 9 wherein the height of the water is determined by utilizing the capacitor as a frequency determining element in an oscillator to provide a signal having a frequency corresponding to the capacitance, and monitoring the frequency of the oscillator signal to determine the height of the water.

Claim 15

Dependent Claim 44 words

The method of claim 10 wherein the height of the water is determined by providing a table of oscillator frequencies and corresponding water heights, and addressing the table in accordance with the frequency of the oscillator signal to determine the height of the water.

Claim 16

Dependent Claim 20 words

The method of claim 10 wherein the oscillator is operated at frequencies on the order of 100 MHz and higher.

Claim 17

Dependent Claim 30 words

The method of claim 9 including the steps of monitoring temperature of the water, and compensating for variations in the capacitance due to temperature dependency of dielectric properties of water.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-06-15	2001-12-15	2002-06-16	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-06-15	2005-12-15	2006-06-16	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-06-15	2009-12-15	2010-06-16	$7700.00	Window Closed / Lapsed

Capacitive water height gauge and method

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