Axial flow turbine structure

Claim 1

An axial flow turbine comprising: an outer generally cylindrical casing, a generally coaxial inner casing, said outer and said inner casings generally defining a plenum chamber therebetween, an annular array of stationary blades disposed within said inner casing having an outer shroud portion, a rotor having an array of rotatable blades on its periphery, said rotatable blades being coaxial and adjacent said stationary blades, an array of arcuate blade ring segments disposed radially outwardly of said rotatable blades, said array of stationary blades comprising arcuate integral vane segments thereof, said stationary blades being supported from said inner casing by arcuate support segments, said arcuate support segments and said inner casing having a track and channel interlock arrangement therebetween, said arcuate support segments and said outer shroud portion of said stationary integral vane segments having a track and channel interlock arrangement therebetween, each arcuate support segment being fixedly attached at one point on its periphery to the inner casing to permit circumferential thermal expansion of said segments, said array of arcuate blade ring segments being supported radially outwardly of said rotatable blades by arcuate support segments having track and channel interlock arrangements with the inner casing and also having a track and channel interlocking support arrangement between an edge of each of said ring segments and the downstream edge of adjacent upstream stationary integral vane segments, said inner casing being supported within said outer casing by generally horizontal keying members, said keying members being received in keyways within said outer casing, and at least two generally vertically disposed pins disposed between each inner casing member and said outer casing providing vertical alignment of said inner casing member with respect to said turbine.