Exhaust chamber of steam turbine, steam turbine, and steam turbine replacement method

A steam turbine replacement method of replacing a part of an existing steam turbine, comprising:

• a step of detaching an outer upper half casing from the steam turbine;
• a step of detaching a flow guide forming a diffuser surface from an outer casing;
• a step of detaching an existing inner casing from an outer lower half casing;
• a step of preparing a rotor including a last blade and attaching a tip-side flow guide to the inner casing which is newly established;
• a step of attaching an inner lower half casing to the outer lower half casing and attaching the rotor to the inner lower half casing;
• a step of attaching a first flow guide and a second lower half flow guide to the outer lower half casing;
• a step of attaching an inner upper half casing to the outer lower half casing where the inner lower half casing is placed;
• a step of attaching a second upper half flow guide to the outer upper half casing;
• and
• a step of attaching the outer upper half casing to the outer lower half casing.

An exhaust chamber of the steam turbine, comprising:

• an outer casing which includes an end wall part in an axial direction and an extension part extending upward in the axial direction from the end wall part;
• a first flow guide formed into an annular shape, the first flow guide forming an upstream region of a diffuser surface of a hub-side flow guide and being fixed to an upstream end portion of the extension part on a radially inner side of the diffuser surface;
• and
• a second flow guide formed into an annular shape, the second flow guide forming a downstream region of the diffuser surface at a position downstream of the first flow guide and on a radially outer side of the extension part, and being fixed to the extension part,
• wherein a recess is formed, which is positioned on a radially outer side of a downstream end portion of the hub-side flow guide and is recessed downstream of the downstream end portion in the axial direction.