SEAL STRUCTURE OF INLET STEAM PIPE FOR STEAM TURBINE

摘要

PURPOSE:To facilitate a disassembly/assembly, while at the same time improving a sealing effect, by arranging such that a conduit attached to a nozzle box is engaged closely to a main steam pipe upon its diameter being resiliently expanded under a main steam pressure inside the conduit. CONSTITUTION:A main steam pipe 2 is detachably inserted by a main steam pipe 2 introducing a main steam 1 generated by a boiler and a conduit 3 is engaged with a nozzle box 4 for connection therewith. The inserting side end of conduit 3 is formed in a double cylindrical shape. The main steam 1 flows into a space 18 formed through the cylindrical portion and consequently has its pressure elevated. An external space 16 formed by a flanged portion projected from the rear portion of double cylindrical portion is filled with a part of turbine exhaust 13 for a subsequential pressure drop. A pressure difference between two spaces is thus used to resiliently deform an outer tubular portion 19 of double cylindrical portion for a resultant expansion of diameter. The tubular portion 19 is thus pressed against the inner wall of main steam pipe 2, and thereby preventing the leakage of main steam 1 to the space 16.