In a steam turbine having a cross-over duct for delivering steam discharged from an intermediate pressure turbine to low pressure turbines, the intermediate pressure turbine provides two outlets for discharging exhaust steam, the low pressure turbine provides two inlets, and the outlets and the inlets are arranged on the same straight line as viewed from a planar direction. One of the outlets and one of the inlets which are close to each other are connected through a cross-over duct, the other of the outlets and the other of the inlets which are far from each other are connected through another cross-over duct, and the cross-over ducts are arranged to be at two stages in the up-down direction.
1. A steam turbine having a cross-over duct for delivering steam discharged from an intermediate pressure turbine to a low pressure turbine,
wherein the intermediate pressure turbine provides two outlets for discharging exhaust steam, the low pressure turbine provides two inlets, said outlets and said inlets are arranged on the same straight line as viewed from a planar direction, one of said outlets and one of said inlets which are in close position each other are connected through a cross-over duct, the other of said outlets and the other of said inlets which are in far position each other are connected through another cross-over duct, and said cross-over ducts are arranged to be at two stages in the up-down direction.
2. The steam turbine according to claim 1 , wherein said cross-over ducts are located just above the axis of the intermediate pressure turbine and lower pressure turbine.
3. The steam turbine according to claim 1 , wherein said cross-over ducts are configured such that a cross-over duct located at a lower stage supports a cross-over duct located at an upper stage.
4. The steam turbine according to claim 1 , wherein each of said cross-over ducts has a duct structure which is composed of a bent pipe and a straight pipe each of which does not have a branch portion or a merging portion.
5. The steam turbine according to claim 1 , wherein each of said cross-over ducts includes a flat pipe in which a shape of cross-section perpendicular to an central axis of the pipe has two diameters which pass through the center of the cross-section, and are orthogonal to each other and different in length each other.
6. The steam turbine according to claim 5 , wherein the cross-sectional shape of said flat duct of said cross-over duct is oval or rectangular.