Patent ID: 6981514

Claim:
A fuel cutoff valve that is attached to an upper wall of a fuel tank, and works by a liquid level in the fuel tank, the fuel cutoff valve comprising: a casing including (i) a casing main body having a valve chamber connected to the fuel tank, (ii) an external conduit located outside the fuel tank, and (iii) a first connection conduit formed in an upper portion of the casing main body to connect the external conduit with the valve chamber, a first float including (i) a float main body accommodated in the valve chamber, being capable of moving up and down, the float main body having (i-a) a bottom-open storage chamber, and (i-b) a second connection conduit to connect the first connection conduit and the storage chamber, an area of the second connection conduit being smaller than that of the first connection conduit, and (iii) a buoyancy body coupled with the float main body and making a resulting specific gravity of the buoyancy body and the float main body smaller than a specific gravity of a fuel; a second float accommodated in the storage chamber, being capable of moving up and down according the liquid level in the fuel tank to open and close the second connection conduit, a specific gravity of the second float being greater than that of the fuel, and; a spring for pressing the second float toward the second connection conduit, wherein the first float is constructed to move up by buoyancy and thereby close the first connection conduit when the liquid lever exceeds a first liquid level, and the second float is constructed to move up by buoyancy and a pressing force of the spring and thereby close the second connection conduit when the liquid level exceeds a second liquid level higher than the first liquid level, and to move down to open the second connection conduit when the level drops below the second liquid level but is still above the first liquid level.