Shaft seal and gas turbine

Abstract

An object of the present invention is to provide a shaft seal which reduces the leakage of gas from the high pressure side to the low pressure side, and has excellent corrosion-resistance, and a gas turbine which is equipped with the shaft seal; in order to achieve the object, the present invention provide a shaft seal comprising a plurality of flexible thin plates having width in the axial direction of a rotary shaft, tips thereof sliding against a peripheral face of said rotary shaft, and outer peripheral bases thereof being secured to a casing side maintaining a gap therebetween, said thin plates being laminated in the peripheral direction of said rotary shaft, enabling the outer periphery of said rotary shaft to be sealed, an acute angle being formed between the thin plates and the peripheral face of said rotary shaft; and a low pressure side side-plate and a high pressure side side-plate which are provided on both sides of said thin plates in the axial direction of said rotary shaft, wherein it further comprises a gas pressure adjusting mechanism, which when said thin plates are viewed cross-sectionally along an imaginary plane which is perpendicular to the direction of their width, the face of each thin plate which faces the rotary shaft is deemed a bottom face and the rear side is deemed a top face, and gas pressure from said high pressure side side-plate to said low pressure side side-plate is applied to said thin plates, ensures that the gas pressure applied to said bottom faces is higher than the gas pressure applied to said top faces at a given point along said cross-sectional face of said thin plates, and a gas turbine comprising such shaft seal.