Analog hall-effect liquid level detector and method
First Claim
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1. A liquid level measuring apparatus comprising:
- a plurality of spaced analog output voltage Hall-effect sensors, said sensors having different voltage output characteristics and being vertically aligned for positioning in a liquid,a float, carrying magnetic means, movably positioned adjacent said plurality of sensors,storage means for storing values of the voltage output of each of said sensors relative to the position of said magnetic means,processing means for determining the liquid level, said processing means comprising;
measuring means connected to each of said sensors for measuring the voltage output of each sensor, to detect sensors activated by said magnetic means, andcalculating means for determining the location of said float as a measurement of the liquid level by comparing the voltage output measured by said measuring means and the values stored in said storage means.
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Abstract
A method and apparatus for measuring a liquid level by a float carrying one or more magnets and movably positioned adjacent spaced analog output voltage Hall-effect sensors. The apparatus is calibrated by moving the float relative to the sensors and measuring the voltage outputs of the sensors relative to the position of the float, and storing the measured values. After calibrating, the voltage outputs of any sensors activated by the presence of the float are measured and compared to the stored values to determine the liquid level. Preferably, the voltage output of at least two sensors are measured while the float is at one position for greater accuracy.
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10 Claims
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1. A liquid level measuring apparatus comprising:
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a plurality of spaced analog output voltage Hall-effect sensors, said sensors having different voltage output characteristics and being vertically aligned for positioning in a liquid, a float, carrying magnetic means, movably positioned adjacent said plurality of sensors, storage means for storing values of the voltage output of each of said sensors relative to the position of said magnetic means, processing means for determining the liquid level, said processing means comprising; measuring means connected to each of said sensors for measuring the voltage output of each sensor, to detect sensors activated by said magnetic means, and calculating means for determining the location of said float as a measurement of the liquid level by comparing the voltage output measured by said measuring means and the values stored in said storage means. - View Dependent Claims (2, 3, 4, 5)
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6. A method of measuring liquid level with a float carrying magnetic means movably positioned adjacent a plurality of spaced analog output voltage Hall-effect sensors positioned in a liquid in which the sensors have different voltage output characteristics, said method comprising:
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(a) calibrating the float and sensors by moving the float relative to the plurality of sensors while measuring the voltage outputs of the sensors relative to the position of the float to obtain calibration values, (b) storing the calibration values and the corresponding float positions, (c) positioning the float and the plurality of sensors in the liquid to be measured, (d) measuring the voltage outputs of any sensors activated by the presence of the magnetic means carried by the float to obtain measurement values, and (e) comparing the measurement values and the stored calibration values to determine the float position as a measurement of the liquid level. - View Dependent Claims (7, 8, 9, 10)
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Specification