Patent ID: 8371126

Claim:
A gas turbine combustor comprising: a combustor outer casing; a combustor inner tube that is arranged within the combustor outer casing via an air passage; a top hat portion to which the combustor outer casing and the combustor inner tube are connected; a plurality of top hat nozzles that are arranged on the top hat portion along a circumferential direction of the top hat portion; a pilot nozzle that is arranged in a center area of the combustor inner tube; and a plurality of premix nozzles that are arranged on an inner circumference of the combustor inner tube along a circumferential direction of the combustor inner tube so as to surround the pilot nozzle, wherein the top hat portion includes: a top hat main body that has a cylindrical shape and a plurality of first fuel passages formed therein along an axial direction of the top hat main body; a cover that forms a cavity communicating with the first fuel passages by covering a concave portion formed on the top hat main body; an inner ring and an outer ring that form a second fuel passage communicating with the first fuel passages by being connected to the top hat main body and being connected to each other; a fuel injecting unit being fixed to the inner ring to communicate with the second fuel passage through a third fuel passage; and a thermal elongation absorbing unit that is provided on at least one of the inner ring and the outer ring to absorb thermal elongation, wherein the thermal elongation absorbing unit includes a thin wall portion that is formed by a groove on at least one of the inner ring and the outer ring.