Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof
First Claim
1. A process for detecting a likelihood of natural ice formation on the surface of a vehicle comprising the steps of:
- positioning a diaphragm having a resonant frequency of vibration on a surface of the vehicle which is exposed to natural ice formation;
exciting said diaphragm at its resonant frequency of vibration;
alternately cooling and heating said diaphragm to temperatures respectively below and above the ambient temperature in accordance with a predetermined, repetitious cycle to artificially create and then melt an accretion of ice when the ambient temperature is near or below the freezing point;
measuring any variation in the resonant frequency of vibration of the diaphragm during said step of alternately and repetitiously cooling and heating the diaphragm;
signaling an alarm whenever said variation exceeds a predetermined value.
1 Assignment
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Accused Products
Abstract
An ice warning system comprising a diaphragm set into vibration at one of its frequencies of resonance by a piezoelectric cell. The diaphragm is coupled thermally to a metallic plate alternately cooled and heated respectively below and above the ambient temperature by Peltier elements connected to a reversible DC current generator. A microprocessor measures any variation of the resonance frequency caused by a deposit of ice on the diaphragm during the cooling or heating periods and delivers an alarm signal if this variation of frequency reaches and/or exceeds a predetermined value. The microprocessor controls the period, intensity and direction of the current delivered by the DC current generator as a function of the ambient temperature and the temperature of the diaphragm. The ice warning system is preferably utilized in the aeronautical field for indicating the likelihood of natural ice formation on the engines and the wings of aircraft.
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Citations
21 Claims
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1. A process for detecting a likelihood of natural ice formation on the surface of a vehicle comprising the steps of:
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positioning a diaphragm having a resonant frequency of vibration on a surface of the vehicle which is exposed to natural ice formation; exciting said diaphragm at its resonant frequency of vibration; alternately cooling and heating said diaphragm to temperatures respectively below and above the ambient temperature in accordance with a predetermined, repetitious cycle to artificially create and then melt an accretion of ice when the ambient temperature is near or below the freezing point; measuring any variation in the resonant frequency of vibration of the diaphragm during said step of alternately and repetitiously cooling and heating the diaphragm; signaling an alarm whenever said variation exceeds a predetermined value. - View Dependent Claims (2, 3)
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4. A process for detecting a likelihood of natural ice formation on the surface of a vehicle comprising the steps of:
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positioning a diaphragm, having a resonant frequency of vibration, on a surface of the vehicle which is exposed to natural ice formation; exciting said diaphragm at its resonant frequency of vibration; measuring the ambient temperature; measuring the temperature of said diaphragm; alternately cooling and heating said diaphragm to temperatures respectively below and above the ambient temperature in accordance with a cycle, the duration of the cycle being dependent on the measured ambient and diaphragm temperature for artificially creating and then melting an accretion of ice when the ambient temperature is near or below the freezing point; measuring any variation in the resonant frequency of vibration of the diaphragm during said step of alternately cooling and heating the diaphragm; signaling an alarm whenever said variation exceeds a predetermined value. - View Dependent Claims (5, 6)
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7. An ice warning system for detecting a likelihood of natural ice formation on a vehicle comprising:
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a transducer adapted to be secured to said vehicle, said transducer comprising a diaphragm, and a vibration exciting means, said diaphragm being responsive to said vibration exciting means for vibrating at one of its frequencies of resonance, said vibration exciting means generating a vibration having a frequency equal to said frequency of resonance of said diaphragm; means for measuring the ambient temperature in the vicinity of said vehicle; means, thermally coupled to said diaphragm for alternately cooling and heating said diaphragm respectively below and above said ambient temperature, said alternate cooling and heating occurring in a predetermined, repetitious cycle which is operable, under conditions where natural ice formation is likely to occur, to artificially create an accretion of ice on said diaphragm during said cooling; frequency measuring means coupled to said vibration exciting means for measuring any variation in the resonant frequency of said diaphragm; and means responsive to said frequency measuring means, for signaling an alarm if the variation in the resonant frequency of the diaphragm exceeds a predetermined value. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An ice warning system for detecting a likelihood of natural ice formation on a vehicle comprising:
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a transducer adapted to be secured to said vehicle, said transducer comprising a diaphragm, and a vibration exciting means, said diaphragm being responsive to said vibration exciting means for vibrating at one of its frequencies of resonance; means for measuring the ambient temperature in the vicinity of said vehicle; means for measuring the temperature of said diaphragm; a microprocessor, said ambient and diaphragm temperature measuring means being connected as inputs to said microprocessor; means, thermally coupled to the diaphragm, for alternately cooling and heating said diaphragm, said alternate cooling and heating being operable for respectively cooling and heating said diaphragm below and above said ambient temperature, in a predetermined, repetitious cycle, said cycle being determined by said microprocessor in dependence on said ambient temperature and said diaphragm temperature and being operable to artificially create an accretion of ice on said diaphragm during said cooling; means, connected to said microprocessor for measuring any variation in the resonant frequency of said diaphragm and for signaling an alarm if any variation in the resonant frequency exceeds a predetermined value. - View Dependent Claims (19, 20, 21)
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Specification