METHOD OF MINIMIZING OR ELIMINATING EROSION BY SOLID PARTICLES IN TWO-FLOW STEAM TURBINES, AND APPARATUS FOR MAKING THE SAME

摘要

A hollow cylindrical portion (36) consisting of segments (36a) is provided at each its end outer surface portion (16) with a cylindrical surface for both mounting and faxing through the mediation of attachment elements of one system of segments (26a, 28a) consisting of an inner ring portion (32) and outer ring portion (30) being coupled with each other by nozzles (34). Each flange part (40) formed on each segment (26a, 28a) outer ring portion (30) outer surface has axis of symmetry of its transverse profile arranged at a location, the distance (X1) of which from the inner face of the outer ring portion (30) is greater than the distance (X). When producing the invented reheat tub (10) a segment portion passing away into the nozzles (18, 34) is cot away from each segment of a dismantled hollow cylindrical portion (14) along generally axial (A) and radial (R) part lines of the segment to thereby separating the segment into three independent part i.e. the hollow cylindrical portion (36) segment (36a) and two annular parts (26, 28). Subsequently each segment (36a) is provided along each axial cut (A) with a first part of an attachment element for future attachment of the annular parts (26, 28) in which damages in the nozzles (34) surfaces are repaired and outer faces of their ring portions (30, 32) are provided with a additional material (70, 76). The additional material is then machined along with the inner peripheral surface of the inner ring portion (32) and inner face of the outer ring portion (30) to a required shape so that the outer ring portion (30) comprises a dovetail groove (72) and has the axis of symmetry of its flange part (40) transverse profile at the distance (X1) from the inner face of the outer ring portion (30), and that the inner ring portion (32) has a sealing edge (77) and the second part of the attachment element on its inner peripheral surface. The reheat tub (10) is then assembled from so produced independent parts and mounted back into the turbine.