Abstract: An axial flow type exhaust gas turbine supercharger (TC) enabling maintainability to be secured by easily attaching/detaching an inner casing, capable of solving problems in thermal expansion and an increase in weight which make its design difficult, and formed to rotate a coaxial compressor with a shaft output provided by the expansion of exhaust gas led into an axial flow turbine (20). The exhaust gas turbine supercharger comprises a gas inlet casing (25) of double structure in which an inner casing (21) and an outer casing (22) formed separately from each other are formed integrally with each other by bolting and a space formed between both casings (21) and (22) forms an exhaust gas flow passage (24) leading the exhaust gas to a turbine nozzle (23). The exhaust gas flow passage (24) is formed all around the periphery of the turbine in the rotating direction and the inner casing (21) is formed detachable in the axial direction.

Abstract: A centrifugal compressor has a plurality of seals arranged at the back of an impeller for sealing the impeller outlet and form an annular space defined at the back of the impeller. The annular space is fed with a cold gas under a higher pressure than that of the air discharged at the impeller outlet. Thus, the back of the impeller is cooled down.