Fuel cutoff valve

A fuel cutoff valve that is attached to an upper portion of a fuel tank and connects and disconnects inside with and from an outside of the fuel tank according to a fuel level in the fuel tank, the fuel cutoff valve comprising:

• a casing that has a casing body forming a valve chest to communicate with the inside of the fuel tank and a connection conduit connecting the valve chest to the outside of the fuel tank;
• a first float that is received in the valve chest in a vertically movable manner and has a valve plug, the valve plug being configured to open and close the connection conduit by the vertical movement of the first float;
• and
• a second float that is made of a material having a greater specific gravity than a specific gravity of the fuel and has a float body located below the first float in a vertically movable manner to form a buoyancy chamber and an air hole formed in an upper portion of the float body to communicate the buoyancy chamber with a space under the first float,
• wherein the fuel cutoff valve is configured such that the first float rises by buoyancy and closes the connection conduit in response to a rise of a fuel level, and
• the second float has a resting state and a moving action in response to rise of the fuel level at a first preset rising rate and second preset rising rate higher than the first preset rising rate respectively,
• the resting state being a state that the second float makes the air come out of the buoyancy chamber via the air hole and interferes with an increase in buoyancy of the buoyancy chamber, and rests at an original position,
• the moving action being an action that the second float retains the air in the buoyancy chamber and rises by increased buoyancy of the buoyancy chamber, and presses the first float up, and then make the valve plug of the first float close the connection conduit.