Thermal level detector for conductive or nonconductive liquids or gases
First Claim
1. A monitoring system comprising:
- a thermistor (13) having a turnover temperature, said thermistor assuming a predetermined resistance when the temperature of said thermistor is above said turnover temperature;
means (15) for thermally coupling said thermistor to a liquid in a vessel when the level of said liquid is above a predetermined level, said liquid lowering the temperature of said thermistor below said turnover temperature when thermally coupled thereto;
means (10) for thermally insulating said coupling means from said vessel;
a tone generator (45, 59, 60, 70, 71, 79-90) for sounding a plurality of warning signals;
a warning circuit (9, 11, 12, 14,
15) directly connected to said thermistor and electrically isolated from said liquid for generating one of said warning signals indicating that the level of said liquid is below said predetermined level when said thermistor assumes said predetermined resistance; and
an annunciator (61-65, 67-69) for displaying said one warning signal.
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Accused Products
Abstract
An all electronic, no moving parts, low cost, warning system, quickly and reliably alerts operator of malfunctions in levels, temperatures and pressures on trucks, farm implements, autos, boats, aircrafts, machinery, etc., which if not immediately attended to, may cause costly damage or even loss of life. Specifically gives aural and visual warning for: Low brake-fluid level, low transmission-fluid level, low engine-oil level, low differential-oil level, low coolant level, even low windshield-washer-fluid level, low fuel level, engine overtemperature, engine oil-pressure loss, loss of vacuum for power-brake assist, etc., in any single function, combination or extension, as pertaining to a particular truck, farm implement, auto, boat, aircraft, or similar machinery, all this being done by means of all-electronic parts, resulting into high reliability.
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Citations
15 Claims
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1. A monitoring system comprising:
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a thermistor (13) having a turnover temperature, said thermistor assuming a predetermined resistance when the temperature of said thermistor is above said turnover temperature; means (15) for thermally coupling said thermistor to a liquid in a vessel when the level of said liquid is above a predetermined level, said liquid lowering the temperature of said thermistor below said turnover temperature when thermally coupled thereto; means (10) for thermally insulating said coupling means from said vessel; a tone generator (45, 59, 60, 70, 71, 79-90) for sounding a plurality of warning signals; a warning circuit (9, 11, 12, 14,
15) directly connected to said thermistor and electrically isolated from said liquid for generating one of said warning signals indicating that the level of said liquid is below said predetermined level when said thermistor assumes said predetermined resistance; andan annunciator (61-65, 67-69) for displaying said one warning signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A warning system for indicating that the level of a liquid in a vessel is below a predetermined level, comprising:
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a thermistor (13) having a turnover temperature, said thermistor assuming a first resistance when the temperature of said thermistor is above said turnover temperature and a second resistance when the temperature of said thermistor is below said turnover temperature; means (15) for thermally coupling said thermistor to said liquid when the level of said liquid is above said predetermined level, said liquid lowering the temperature of said thermistor below said turnover temperature when thermally coupled thereto; means (10) for thermally insulating said coupling means from said vessel; and a warning circuit (9, 11, 12, 14,
15) directly connected to said thermistor and electrically isolated from said liquid for generating a warning signal indicating that the level of said liquid is below said predetermined level when said thermistor assumes said first resistance. - View Dependent Claims (11, 12)
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13. A warning system for indicating that the pressure of a gas is above a predetermined level in a vacuum chamber, comprising:
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a thermistor (21) having a turnover temperature and only a positive temperature coefficient, said thermistor assuming a first resistance when the temperature of said thermistor is above said turnover temperature and a second resistance less than said first resistance when the temperature of said thermistor is below said turnover temperature , said gas lowering the temperature of said thermistor below said turnover temperature when said gas is thermally coupled to said thermistor and the pressure of said gas is above said predetermined level; and a warning circuit (16, 17, 19, 20,
22) directly connected to said thermistor and electrically isolated from said gas for generating a warning signal indicating that the pressure of said gas is above said predetermined level when said thermistor assumes said second resistance. - View Dependent Claims (14, 15)
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Specification