Patent ID: 7523614

Claim:
A combustor comprising: a pilot nozzle provided around an axis of the combustor and performing diffusion combustion; main nozzles provided circumferentially around the pilot nozzle so as to be equally spaced with each other, and performing premixed combustion; a combustor basket covering outside circumferences of the pilot nozzle and the main nozzles; an external cylinder provided around an outside circumference of the combustor basket so as to form a passageway of a compressed air between an inside wall thereof and an outside wall of the combustor basket; a punched metal plate which is a perforated plate formed in a ring shape, covers an entrance on first distal sides of the main nozzles in a space between the combustor basket and the external cylinder; ribs each having a supporting portion which supports the punched metal plate to the external cylinder, and a plate-shaped portion which is connected to the supporting portion and installed toward a central axis of the combustor basket so as to be in close contact with the combustor basket, the ribs being installed along an inside circumference of the external cylinder so as to be equally spaced with each other; a cylinder which is connected to ends on a side of bases of the main nozzles of the combustor basket, having outside wall thereof upwardly curved from a side of tips of the main nozzles toward a side of bases of the main nozzles and having tips on a side of bases of the main nozzles formed in a semicircular cross-sectional shape: turning vanes being provided between the main nozzles that are circumferentially adjacent to each other and bending from bases toward tips of the main nozzles and from a side of outside circumferences of the main nozzles toward a central axis; and a back surface wall covering a side of bases of the main nozzles of the external cylinder, being provided with a curved surface on a side of an inside wall of the external cylinder so as to serve as a concave surface in a shape of a mortar to a side of bases of the main nozzles, wherein the curvature of the mortar-shaped portion corresponds to the outside circumference of the semicircle-shaped portion of the cylinder.