SEALING STRUCTURE FOR JOINT SURFACES OF FLANGES OF GAS TURBINE

摘要

In a gas turbine of a steam cooling system, flange joint surfaces such as the surfaces of joint portions of a rotor disc do not permit a buffer plate, such as a gasket, to be inserted therebetween and no sufficient sealing surface pressure can be secured due to a large contact area of the flange joint surfaces, so that the leakage of cooling steam from these joint surfaces poses a very important problem. Therefore, providing a sealing structure having an improved sealability with respect to such joint surfaces is demanded. The improved sealing structure for joint surfaces (7) of flanges of a gas turbine having a steam cooling structure comprises labyrinthine grooves (8) provided in at least either one of the flange joint surfaces (7), and the sealability of the gas turbine is improved owing to a combination of a labyrinthine effect and a high surface pressure obtained by a decrease in the area of the flange joint surfaces, thus enabling a gas turbine of a high reliability to be obtained.