Stator blade assembly for turbo machines

Abstract

The stator blades of a stage of an axial flow turbo machine are assembled in an arcuate series, as by insertion of the journals at the outer ends of the blades in the stator housing. A one-piece arcuate inner shroud ring is formed with aperture spaced circumferentially comparable to the spacing of the inner ends of the blades in the series. The diameter of the apertures exceeds the diameter of the blade journals. Force is applied to the ends of the ring to control or bow the same sufficiently to permit insertion of the contracted ring into the series of blades. Upon insertion of the ring, the contracting force is relieved, permitting the ring to expand to normal contour whereby the inner journals of the blades become positioned in the apertures of the ring. Thereafter annular bearings are inserted in the space between the journals and the bores of the apertures.

We claim: 
     
       1. The method of assembling an arcuate shroud ring to the inner ends of an arcuate series of stator blades extending in a radial direction inwardly from a machine casing, the ring having apertures spaced apart circumferentially for receiving in registration therewith said blade ends, the method including contracting the shroud ring by .[.applying a force thereto.]. .Iadd.connecting an extensible rod to opposed ends thereof and retracting the rod .Iaddend.to reduce the diameter of the shroud ring to a diameter less than that described by the ends of the blades in the series whereby at least one blade receiving aperture in the ring is insertable into one of said blade ends,   inserting said one aperture into said one blade end, and   .[.relieving said contracting force to permit.]. .Iadd.extending the rod to expand .Iaddend.the shroud ring .[.to expand.]. .Iadd.to a normal contour and .Iaddend.whereby the remaining apertures move into receiving registration with the remaining blade ends in said series.   
     
     
       2. The method of claim 1 wherein said one blade end is carried on the last blade in said series. 
     
     
       3. The method of claim 2 wherein the shroud ring is semi-circular in form. .Iadd.4. The method of claim 1 further including the step of fixing a bearing in each aperture in the shroud ring after the apertures have moved into registration with the blade ends to secure the blades against axial displacement. .Iaddend. .Iadd.5. The method of claim 4 wherein the relieving step includes the steps of rocking the shroud ring downward while contracted whereby a plurality of blade ends successively enter ring apertures, and then relieving the contracting force whereby the shroud ring expands to the normal contour and the remaining shroud ring apertures move into receiving registration with the remaining blade ends. .Iaddend.