SEAL STRUCTURE FOR VAPOR TURBINE

摘要

It is intended to improve sealability between a steam pipe and a casing of a steam turbine by increasing a contact pressure of a sealing surface of a stack ring without cost increase. A stack ring 10A is formed by an outer ring 10a and an inner ring 10b and is inserted in an annular gap s1 formed between an inlet sleeve 16 and the inner casing 18. The outer periphery of the outer ring 10a and the inner periphery of the inner ring 10b each have a land part 40 having a flat face and taper faces 42, 44 formed on upper and lower sides of the land part 40. A ratio of L 1 to L 0 is 0.3 to 0.7 where L 1 is a length of the land part 40 and L 0 is a total length in the up-down direction. A ratio of S to So is not less than 0.95 where S is an area of the cross sectional shape of the outer ring 10a or the inner ring 10b and So is an area of a virtual rectangle BCDE and the taper faces 42, 44 have an inclined angle of 1° to 10° with respect to the one edge.