BORE TUBE ASSEMBLY FOR STEAM COOLING TURBINE ROTOR

PROBLEM TO BE SOLVED: To provide a cooling route to enable efficient supply of a cooling medium to selected high temperature gas parts, and efficient return of steam for cooling after use. SOLUTION: A lateral board tube assembly 48 for a turbine is provided for supplying steam for cooling to high-temperature gas parts of turbine wheels 38, 40, 42, 44. One pair, consisting of an inside tube 52 and an outside tube, comprises a steam supply route centered around a return route on the inside. The front ends of these tubes communicate with an end cap assembly, having a plurality of groups of surrounding holes communicating with a first group and a second group of radial tubes. This enables cooling steam is supplied to the radial tubes from the center route to cool the bucket. Meanwhile, return steam from the bucket flows in the return route of the same shaft via a second group of openings in the end cap. A radial uniaxial direction flow converting device which has vortex propeller is provided in the end cap.