Capacitive liquid sensor
First Claim
1. A method of gauging the amount or level of substance in a container, the method comprising the steps of;
- sensing level of the substance by measuring a first capacitance, sensing dielectric constant of the substance by measuring a second capacitance, producing a level signal having a frequency proportional to one of the first and second capacitance and a pulse width proportional to the other of the first and second capacitance.
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Accused Products
Abstract
A capacitive level gauge for placement in a container (12) determines the level of substance (14) in the container (12). The gauge (10) includes a measurement capacitor (C1) for measuring level and a reference capacitor (C2) for determining dielectric constant of the substance (14). A controller (34) is responsive to the capacitors (C1, C2) for producing a level signal which simultaneously indicated the level and dielectric constant of the material. The level signal includes a frequency which is representative of dielectric constant and a pulse width representative of level. The gauge (10) supports a first pair of parallel conductive members (26, 28) to establish the measurement capacitor (C1) and a second pair of parallel conductive members (28, 32) spaced along the gauge and below the measurement capacitor (C1) to establish the reference capacitor (C2).
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Citations
6 Claims
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1. A method of gauging the amount or level of substance in a container, the method comprising the steps of;
- sensing level of the substance by measuring a first capacitance, sensing dielectric constant of the substance by measuring a second capacitance, producing a level signal having a frequency proportional to one of the first and second capacitance and a pulse width proportional to the other of the first and second capacitance.
- View Dependent Claims (2, 3)
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4. A method of gauging the amount or level of substance in a container, the method comprising the steps of;
- sensing level of the substance by measuring a level capacitance, sensing dielectric constant of the substance by measuring a reference capacitance, producing a reference signal having a timing component indicative of the reference capacitance and independent of the level capacitance, and receiving the reference signal and producing a level signal having a timing component indicative of level capacitance and the timing component indicative of reference level capacitance.
- View Dependent Claims (5, 6)
Specification