Steam turbine, blade, and method

Abstract

A stator blade ring comprising a plurality of stator blade modules defining an annular chamber is provided. The plurality of stator blade modules comprises an elongated blade portion comprising a first and a second blade shell portion, a longitudinal passageway, and at least one opening extending through at least one of the first and the second blade shell portion to the longitudinal passageway, an inner portion brazed to a first longitudinal end of the elongated blade portion, wherein the inner portion comprises a through hole forming a portion of the annular chamber, and an inner passageway extending from the through hole to the longitudinal passageway, and an outer portion brazed to a second longitudinal end of the elongated blade portion and engaged to a steam turbine, the outer portion comprising an outer passageway open to a surface of the steam turbine and the longitudinal passageway.

What is claimed is: 
     
         1 . A stator blade ring for a steam turbine, the stator blade ring comprising:
 a plurality of stator blade modules defining an annular chamber, wherein each of the plurality of stator blade modules comprises:
 an elongated blade portion comprising a first blade shell portion, a second blade shell portion brazed to the first blade shell portion, a longitudinal passageway; and at least one opening extending through at least one of the first blade shell portion and the second blade shell portion to the longitudinal passageway; 
 an inner portion brazed to a first longitudinal end of the elongated blade portion, wherein the inner portion comprises a through hole forming a portion of the annular chamber, and an inner passageway extending from the through hole to the longitudinal passageway; and 
 an outer portion brazed to a second longitudinal end of the elongated blade portion and engaged to the steam turbine, wherein the outer portion comprises an outer passageway open to a surface of the steam turbine and the longitudinal passageway. 
   
     
     
         2 . The stator blade ring of  claim 1 , wherein the outer portion further comprises:
 a first groove configured to engage a first ridge in the surface of the steam turbine; and   a second groove configured to engage a second ridge in the surface of the steam turbine.   
     
     
         3 . The stator blade ring of  claim 2 , wherein the first groove and the second groove are offset relative to the inner portion. 
     
     
         4 . The stator blade ring of  claim 3 , wherein a groove in the inner portion forms a circumferential groove in the stator blade ring, wherein the circumferential groove is engaged by a metal ring configured to lock the plurality of stator blade modules together. 
     
     
         5 . The stator blade ring of  claim 4 , wherein the circumferential groove faces inwardly towards a center of the stator blade ring. 
     
     
         6 . A multi-stage steam turbine, comprising:
 a rotor assembly comprising at least one impeller;   a bearing connected to the rotor assembly, wherein the bearing is configured to rotatably support the rotor assembly; and   a stator blade ring for the last stage of the steam turbine, wherein the stator blade ring comprises a plurality of stator blade modules defining an annular chamber, wherein each of the plurality of stator blade modules comprises:
 at least one elongated blade portion comprising a first blade shell portion and a second blade shell portion brazed to the first blade shell portion; 
 an inner portion brazed to a first longitudinal end of the at least one elongated blade portion, wherein the inner portion comprises a through hole forming a portion of the annular chamber; and 
 an outer portion brazed to a second longitudinal end of the at least one elongated blade portion and engaged to a surface of the steam turbine, 
   wherein the at least one elongated blade portion of at least one of the plurality of stator blade modules further comprises a first longitudinal passageway and an opening for steam condensate to enter the first longitudinal passageway,   wherein the inner portion of the at least one of the plurality of stator blade modules comprises a first inner passageway extending from the through hole to the first longitudinal passageway for the steam condensate to flow between the annular chamber and the first longitudinal passageway;   wherein the at least one elongated blade portion of another of the plurality of stator blade modules comprises a second longitudinal passageway, the inner portion of the another of the plurality of stator blade modules comprising a second inner passageway extending from the through hole to the second longitudinal passageway for allowing the steam condensate to flow between the annular chamber and the second longitudinal passageway, and   wherein the outer portion of the another of the plurality of stator blade modules comprises an outer passageway extending from the second longitudinal passageway and opening to the surface of the steam turbine for allowing the steam condensate to flow out of the stator blade ring.   
     
     
         7 . The steam turbine of  claim 6 , wherein a first groove in the outer portion of each of the plurality of stator blade modules is engaged by a first ridge on the surface of the steam turbine. 
     
     
         8 . The steam turbine of  claim 7 , wherein a second groove in the outer portion of each of the plurality of stator blade modules is engaged by a second ridge on the surface of the steam turbine. 
     
     
         9 . The steam turbine of  claim 8 , wherein the first groove faces upstream and the second groove faces downstream of a flow of working fluid within the steam turbine. 
     
     
         10 . A method of making a blade module for a stator blade ring in the last stage of a steam turbine, wherein the blade module comprises an elongated blade portion, an inner portion, and an outer portion, the method comprising:
 brazing a first edge and a second edge of a first blade shell portion to a first edge and a second edge of a second blade shell portion to form a longitudinal passageway in the elongated blade portion;   forming a through hole in the inner portion;   forming an inner passageway in the inner portion extending from a surface of the inner portion to the through hole;   brazing a first longitudinal end of the elongated blade portion to the surface of the inner portion such that the longitudinal passageway is open to the inner passageway;   forming an outer passageway in the outer portion extending from a first surface of the outer portion to a second surface of the outer portion; and   brazing a second longitudinal end of the elongated blade portion to the first surface of the outer portion such that the longitudinal passageway is open to the outer passageway.