Patent ID: 7409861

Claim:
A concentration detector for detecting a concentration of a liquid fuel in a container, wherein the concentration detector comprises a rotating mechanism positioned underneath a level of the liquid fuel and having a rotational center, the rotating mechanism comprising: a first float having a specific gravity less than the specific gravity of the liquid fuel, a volume equivalent to “V” and a mass equivalent to “M”, and for which the distance between the mass center of the first float and the rotational center is “L” on an X-Y plane; a second float connected with the first float, having a specific gravity less than the specific gravity of the liquid fuel, a volume equivalent to “V” and a mass equivalent to “r*M”, wherein the distance between a mass center of the second float and the rotational center is “L” on the X-Y plane, and the mass center of the second float, the rotational center and the mass center of the first float constitute an included angle of 120°, where r is a constant greater than zero; a third float connected with the first float and the second float, having a specific gravity less than the specific gravity of the liquid fuel, a volume equivalent to “V” and a mass equivalent to “r 2 *M”, wherein a distance between the mass center of the third float and the rotational center is “L” on the X-Y plane, and the mass center of the third float, the rotational center and the mass center of the second float constitute an included angle of 120°, thereby a variation in the concentration of the liquid fuel is acquired by inspecting a change in a rotational direction of the rotating mechanism.