FLEXIBLE INLET PIPE OF HIGH AND INTERMEDIATE PRESSURE STEAM TURBINE

摘要

PURPOSE: A flexible inlet pipe of a high pressure and intermediate pressure steam turbine is provided to prevent the temperature increase of a casing by refrigerating a steam inlet pipe using steam. CONSTITUTION: A casing(11) of a steam turbine has a main steam inlet pipe(14) and a reheated steam inlet pipe(1) integrated with the casing. Main steam(30) flows into a high pressure turbine unit(17) through an inlet pipe(14), and reheated steam(31) flows into an intermediate pressure turbine unit(19) through another inlet pipe(1). Then, a rotor(12) is driven. A double pipe portion(2) is prepared in the inlet pipe(1) to form an annular groove(3). An expanded diameter portion(4) is prepared in the lower end of the double pipe portion. Since vertical sliding is performed between the expanded diameter portion and a flange(5) fixed in a heat shielding unit(21), thermal extension is absorbed. Low temperature steam flows into the annular groove from a space(23) in the casing through a hole and circulates in the annular groove. Thereafter, the low temperature steam flows out to a steam path of the intermediate pressure turbine unit. Therefore, the inside of the annular groove is refrigerated and temperature increase of the casing is prevented.