Turbine diaphragm seal structure

Claim 1

In an axial flow gas turbine machine, in combination, a casing of generally circular cross-section, a rotor disposed within said casing and defining therewith an annular motive fluid passage, an annular row of blades carried by the rotor and extending radially outwardly across said passage, a diaphragm structure disposed within the casing in encompassing concentric relation with the rotor and having an annular array of stationary blades extending across said passage adjacent said rotor blades, said stationary blades being cooled by passage of cooling fluid therethrough, said diaphragm including an arcuately segmented inner shroud ring carried by the stationary blades and having an arcuately segmented radially inwardly extending rib and a radially inwardly directed flange, an annular seal housing structure having a radially outwardly extending rib portion overlapping a portion of the rib on the inner shroud ring, said annular housing having a cooling fluid receiving and expending means, an arcuate segmented seal member disposed off the upstream end of said housing in sealing relation with said rotor, an annular array of arcuately segmented seal segments carried by the seal housing in sealing relation with the rotor, guide means eccentrically mounted in one side of said rib portions to permit centering of the seal housing and cooperating with the other side of said overlapping rib portions to permit relative radial movement between the diaphragm segments and the seal housing structure and restraining relative movement of the seal housing structure, an upstream housing wall comprising a plurality of arcuate segmented radially directed seal plates overlapping and in frictional engagement against said radially inwardly directed flange, and a biasing means maintaining the frictional engagement between said seal plates and said flange.