Apparatus for measuring the level of a liquid in a tank
First Claim
Patent Images
1. Apparatus for measuring the level of a liquid in a tank comprising:
- at least one probe disposed in the tank for at least partial immersion in the liquid;
means electrically coupled to said probe for providing a resonant circuit defining a resonant frequency, said resonant frequency being a function of the level of immersion of the probe by the liquid in the tank;
a generator for applying an electrical input signal to said probe resonant circuit;
means for determining said probe resonant frequency;
means electrically coupled to said probe resonant frequency determining means for computing and displaying the quantity of said liquid in said tank; and
at least another probe disposed in said tank and connected in electrical parallel relation with said at least one probe, each probe connected in said resonant circuit having a distinct resonant frequency corresponding to a predetermined liquid level in the tank, and each probe resonant frequency lying within a range of frequencies which do not overlap with one another between maximum and minimum probe immersion conditions;
whereby the quantity of liquid in the tank can be determined from said resonant frequency measurement.
4 Assignments
0 Petitions
Accused Products
Abstract
A fuel gauging system for use in determining the level of fuel in a tank. The system incorporates a resonant circuit for measuring the resonant frequency of at least one probe immersed in the fuel located in the tank. From measurements of variations of the frequency of resonance, the level of liquid in the tank is determined, and the fuel quantity is then calculated and displayed.
68 Citations
13 Claims
-
1. Apparatus for measuring the level of a liquid in a tank comprising:
-
at least one probe disposed in the tank for at least partial immersion in the liquid; means electrically coupled to said probe for providing a resonant circuit defining a resonant frequency, said resonant frequency being a function of the level of immersion of the probe by the liquid in the tank; a generator for applying an electrical input signal to said probe resonant circuit; means for determining said probe resonant frequency; means electrically coupled to said probe resonant frequency determining means for computing and displaying the quantity of said liquid in said tank; and at least another probe disposed in said tank and connected in electrical parallel relation with said at least one probe, each probe connected in said resonant circuit having a distinct resonant frequency corresponding to a predetermined liquid level in the tank, and each probe resonant frequency lying within a range of frequencies which do not overlap with one another between maximum and minimum probe immersion conditions; whereby the quantity of liquid in the tank can be determined from said resonant frequency measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. Apparatus for measuring the level of a liquid in a tank comprising:
-
a plurality of probes disposed in the tank for at least partial immersion in the liquid; means electrically coupled to each probe for providing a series LC resonant circuit defining a distinct resonant frequency, said resonant frequency being a function of the level of immersion of the probe in the liquid; means connecting said series LC resonant circuits in electrical parallel relation, said LC resonant circuits being operable in ranges of resonance which do not overlap one another; a generator for applying electrical input signals at selected ones of different frequencies to said probe resonant circuits; means for determining said probe resonant frequencies; and means electrically coupled to said probe resonant frequency determining means for comparing stored resonant frequencies with known liquid levels and computing and displaying the quantity of said liquid in said tank; whereby the quantity of liquid in the tank can be determined from said resonant frequency measurements. - View Dependent Claims (9, 10, 12, 13)
-
-
11. In an aircraft having a fuel tank, apparatus for measuring the level of fuel in the tank comprising:
-
a plurality of probes disposed in the tank for at least partial immersion in the fuel; each probe including an elongate air gap capacitor and an inductor associated with it for providing an LC resonant circuit defining a distinct resonant frequency, said resonant frequency being a function of the level of fuel in the air gap; means connecting said LC resonant circuits of each probe in electrical parallel relation, said LC resonant circuits operable in ranges of resonance which do not overlap one another in their normal course of operation; a generator for applying electrical input signals at selected ones of different frequencies to said probe resonant circuits; means for determining said probe resonant frequencies; and means electrically coupled to said probe resonant frequency determining means for comparing stored resonant frequencies with known fuel levels in the tank and computing and displaying the fuel quantity in said tank; whereby the fuel level in the tank and hence quantity of fuel can be determined from said resonant frequency measurements.
-
Specification