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US 4,163,391 AGranted
Device for checking the level of a liquid in a tank
AssigneeJaeger
InventorsJean-Jacques Bezard, Charles-Henri Jourdain, Bruno Lalanne
Life of this patent
Estimating the term…
Abstract
A device for checking the level of a liquid in a tank, for example a car fuel tank, has an electrical resistance probe partly immersed in the liquid and energized with a constant current. The voltage across the probe at switching on is stored and used as a reference for comparing with the increased voltage after the element has been heated to a value dependent on the length of resistor cooled by the liquid.
Claims10
Apparatus for monitoring the level of a liquid in a tank, comprising:
- an electrical resistance probe having a resistance value which increases with temperature, said probe arranged to be immersed to a level dependent upon the liquid level in said tank such that, when said probe is supplied with a constant current, the temperature and the resistance of said probe increase in dependence on the amount of said probe which is immersed;
- means energizable for supplying a constant current through said probe to produce a voltage across said probe dependent on the temperature of said probe;
- and
- means for comparing the initial voltage across said probe upon energization of said constant current supplying means with the voltage across said probe at a predetermined time after energization of said constant current supplying means, and for providing an indication dependent on said comparison, said indication being representative of the liquid level in said tank and being substantially independent of ambient temperature.
1 more element
Dependencies are inferred from the claim text.