Self cleaning liquid level detector
First Claim
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1. Apparatus for detecting the contents level of a container having a wall subject to fouling by contaminants, including a wall portion having a conductive surface, comprising:
- first responsive means, coupled to the conductive surface and responsive to input signals of first and second values, for selectively applying signals of first and second forces to the conductive surface, the first force being less than the second force and the second force being operative to vibrate the wall portion sufficient to dislodge contaminants from the wall portion;
sensing means, positioned adjacent to the conductive surface, for sensing a parameter which is a function of the forces and of the contents level of the container; and
means for generating an indicating signal representative of the parameter to indicate the contents level of the container;
wherein said sensing means has an output and wherein said means for generating an indicating signal comprises second responsive means, responsive to the frequency and amplitude of the output of said sensing means, for generating a fluids-status indicating signal indicative of the presence of contents and a contaminants-status indicating signal indicative of the presence of contaminants;
wherein said second responsive means comprises third responsive means, responsive to a first modal response of the output of said sensing means which exhibits a linear response to variations in content level of the container in the presence of contaminants, for generating the fluids-status indicating signal and fourth responsive means, responsive to a second modal response which exhibits a non-linear response to the content level of the container in the presence of contaminants, for generating the contaminants-status indicating signal.
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Abstract
A method of detecting an effluent level in an aircraft lavatory holding tank and a device for practicing the method. The device uses electrodynamic forces of different values generated by an electro-impulse solenoid to determine whether a detector is contaminated, to dislodge contaminants, and to measure the fluid level in the holding tank when the detector is clean enough to produce an accurate reading.
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Citations
22 Claims
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1. Apparatus for detecting the contents level of a container having a wall subject to fouling by contaminants, including a wall portion having a conductive surface, comprising:
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first responsive means, coupled to the conductive surface and responsive to input signals of first and second values, for selectively applying signals of first and second forces to the conductive surface, the first force being less than the second force and the second force being operative to vibrate the wall portion sufficient to dislodge contaminants from the wall portion; sensing means, positioned adjacent to the conductive surface, for sensing a parameter which is a function of the forces and of the contents level of the container; and means for generating an indicating signal representative of the parameter to indicate the contents level of the container; wherein said sensing means has an output and wherein said means for generating an indicating signal comprises second responsive means, responsive to the frequency and amplitude of the output of said sensing means, for generating a fluids-status indicating signal indicative of the presence of contents and a contaminants-status indicating signal indicative of the presence of contaminants; wherein said second responsive means comprises third responsive means, responsive to a first modal response of the output of said sensing means which exhibits a linear response to variations in content level of the container in the presence of contaminants, for generating the fluids-status indicating signal and fourth responsive means, responsive to a second modal response which exhibits a non-linear response to the content level of the container in the presence of contaminants, for generating the contaminants-status indicating signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Apparatus for containing liquid and for indicating the contents level thereof, comprising:
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a container having at least one wall subject to fouling by contaminants, said wall having a portion including a conductive surface; means for selectively generating input signals of first and second values; first responsive means, coupled to the conductive surface and responsive to the input signals of first and second values, for selectively applying first and second forces to said conductive surface, the first force being less than the second force and the second force being operative to vibrate the wall portion sufficient to dislodge contaminants from the wall portion; sensing means, positioned adjacent to the conductive surface, for sensing a parameter which is a function of the forces and of the contents level of the container; and means for generating an indicating signal representative of the parameter to indicate the contents level of the container; wherein said sensing means has an output and wherein said means for generating an indicating signal comprises second responsive means, responsive to the frequency and amplitude of the output of said sensing means, for generating a fluids-status indicating signal indicative of the presence of contents and a contaminants-status indicating signal indicative of the presence of contaminants; wherein said second responsive means comprises third responsive means, responsive to a first modal response of the output of said sensing means which exhibits a linear response to variations in content level of the container in the presence of contaminants, for generating the fluids-status indicating signal, and fourth responsive means, responsive to a second modal response which exhibits a non-linear response to the content level of the container in the presence of contaminants, for generating the contaminants-status indicating signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method for detecting the contents level of a container including a wall subject to fouling by contaminants, comprising:
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a first step of generating an input signal to apply to the wall a first mechanical force representative of the input signal; a second step of detecting a first parameter which is a function of the first mechanical force and which is indicative of a tentative contents level of the container; a third step of generating a level-indicating signal from the detected first parameter if the detected first parameter is below a predetermined value; a fourth step of detecting a second parameter indicative of contamination of the container; a fifth step of generating a contaminants-indicating signal from the detected second parameter if the detected second parameter is below a predetermined value; and a sixth step of analyzing the level-indicating signal and the contaminants-indicating signal for determining a status signal indicating the reliability of the level-indicating signal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification