Turbine casing with raised horizontal joint

Claim 1

In an elastic fluid turbine having a rotor with a plurality of bucket wheels and a plurality of stationary nozzle diaphragms separating said wheels and having outer ring portions dividing regions of gradually decreasing fluid pressure, the improvement comprising: an outer casing communicating at its bottom side with a region of fluid pressure lower than that in said diaphragm regions, an inner casing disposed thin said outer casing and having a wrapper wall and a plurality of spaced radial wall portions, said wall portions and said outer diaphragm ring portions cooperating to define extraction conduits from said diaphragm pressure regions, said conduits gradually increasing in crosssectional area from the top of the inner casing to the horizontal centerline of the rotor, said inner casing being divided into upper and lower sections along a horizontal joint disposed substantially higher than said centerline, whereby the sealing surface at the joint is smaller than it would be if located at the centerline, and bolting means sealingly connecting said upper and lower sections and accessible from the outside of said inner casing.