Inert gas distribution system for a fuel tank

A fuel tank system comprising:

• a fuel tank having a number of compartments, the number of compartments positioned in a wing of an aircraft having a positive dihedral;
• an inert gas system having a tube positioned in the number of compartments, the tube having a number of openings disposed in the number of compartments and configured for an inert gas in the fuel tank system to pass into the number of compartments of the fuel tank;
• and
• a valve system having a number of valves disposed in the number of compartments, a valve in the number of valves comprising:
• a cylindrical portion configured to be connected to the tube and configured to rotate around the tube to open and close the openings based on a position of the cylindrical portion;
• and
• a float structure connected to the cylindrical portion, wherein the float structure is configured to be buoyant in the fuel and to rotate the cylindrical portion depending on a fuel level in the number of compartments, the valve system configured to control an amount of the inert gas that flows from the openings into the fuel tank based on a level of fuel in the fuel tank;
• wherein the number of valves are configured to manage the delivery of inert gas to the number of compartments based on a level of fuel in each compartment, such that when a fuel level in a first compartment is below a first level the valve is closed, when the fuel level in a second compartment is at a relatively higher level than the first compartment the valve is partially open, and when the fuel level in a third compartment is at a relatively higher level than the second compartment the valve is fully open.

A method of managing an inert gas in a fuel tank, the method comprising:

• sending the inert gas into a tube extending into the fuel tank, wherein the fuel tank has a number of compartments, the tube has a number of openings in the number of compartments, and a number of valves are disposed in the number of compartments, the fuel level in the number of compartments being at a different level;
• raising and lowering a number of floats connected to the number of valves with respect to a fuel level so as to rotate a number of cylindrical members in the number of valves;
• and
• controlling an amount of the inert gas flowing from the openings using a valve system based on a level of fuel relative to the openings, such that when a fuel level in a first compartment is below a first level the valve is closed, when the fuel level in a second compartment is at a relatively higher level than the first compartment the valve is partially open, and when the fuel level in a third compartment is at a relatively higher level than the second compartment, the valve is fully open.