Steam turbine

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 36 inches rotating at 3000 rpm;
• and
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line consisting of at least one straight line segment and at least one circular arc subtending angles of at least 140 degrees.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 36 inches rotating at 3000 rpm;
• and
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line such that a plurality of straight lines mutually subtend angles of at least 140 degrees.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• and
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a single circular arc.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• and
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line consisting of at least one straight line segment and at least one circular arc subtending angles of at least 140 degrees.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• and
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line such that a plurality of straight lines mutually subtend angles of at least 140 degrees.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 36 inches rotating at 3000 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a single circular arc;
• and
• the ratio L/D of the axial length L between a central position of said last-stage turbine rotor blades and a rearmost portion of said conical portion to the blade-tip diameter D of said last-stage turbine rotor blades is within the range of 0.32 to 0.48.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 36 inches rotating at 3000 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line consisting of at least one straight line segment and at least one circular arc subtending angles of at least 140 degrees;
• and
• the ratio L/D of the axial length L between a central position of said last-stage turbine rotor blades and a rearmost portion of said conical portion to the blade-tip diameter D of said last-stage turbine rotor blades is within the range of 0.32 to 0.48.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 36 inches rotating at 3000 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line such that a plurality of straight lines mutually subtend angles of at least 140 degrees;
• and
• the ratio L/D of the axial length L between a central position of said last-stage turbine rotor blades and a rearmost portion of said conical portion to the blade-tip diameter D of said last-stage turbine rotor blades is within the range of 0.32 to 0.48.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a single circular arc;
• and
• the ratio L/D of the axial length L between a central position of said last-stage turbine rotor blades and a rearmost portion of said conical portion to the blade-tip diameter D of said last-stage turbine rotor blades is within the range of 0.32 to 0.48.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line consisting of at least one straight line segment and at least one circular arc subtending angles of at least 140 degrees;
• and
• the ratio L/D of the axial length L between a central position of said laststage turbine rotor blades and a rearmost portion of said conical portion to the blade-tip diameter D of said last-stage turbine rotor blades is within the range of 0.32 to 0.48.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line such that a plurality of straight lines mutually subtend angles of at least 140 degrees;
• and
• the ratio L/D of the axial length L between a central position of said last-stage turbine rotor blades and a rearmost portion of said conical portion to the blade-tip diameter D of said last-stage turbine rotor blades is within the range of 0.32 to 0.48.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 36 inches rotating at 3000 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a single circular arc;
• and
• at least one circular arc forming said vertical cross-sectional shape of said inner wall of said conical portion has a radius of curvature within the range of 0.9 times to 1.8 times the blade length of said last-stage turbine rotor blades, or it has a central angle β of at least 45 degrees.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 36 inches rotating at 3000 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line consisting of at least one straight line segment and at least one circular arc subtending angles of at least 140 degrees;
• and
• at least one circular arc forming said vertical cross-sectional shape of said inner wall of said conical portion has a radius of curvature within the range of 0.9 times to 1.8 times the blade length of said last-stage turbine rotor blades, or it has a central angle β of at least 45 degrees.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a single circular arc;
• and
• at least one circular arc forming said vertical cross-sectional shape of said inner wall of said conical portion has a radius of curvature within the range of 0.9 times to 1.8 times the blade length of said last-stage turbine rotor blades, or it has a central angle β of at least 45 degrees.

A steam turbine comprising:

• a high-pressure turbine to which primary steam is supplied;
• a low-pressure turbine on a final-stage side of said high-pressure turbine and having last-stage turbine rotor blades;
• a turbine rotor formed as an integral rotor member by which said high-pressure turbine and said low-pressure turbine are coupled;
• an integral casing within which said high-pressure turbine and said low-pressure turbine are accommodated;
• a downward-exhaust type of exhaust chamber formed in said casing for exhausting in a downward direction exhaust steam that is expelled from said low-pressure turbine;
• a high-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on an initial-stage side of said high-pressure turbine;
• and
• a low-pressure-side journal bearing for supporting said turbine rotor in a rotatable manner on a final-stage side of said high-pressure turbine;
• wherein:
• said primary steam has a steam pressure of at least 100 kg/cm2 and a steam temperature of at least 500° C.;
• said steam turbine has a rated power of at least 100 MW;
• said last-stage turbine rotor blades are rotor blades of an effective blade length of at least 33.5 inches rotating at 3600 rpm;
• the vertical cross-sectional shape of an inner wall of a conical portion forming a rear portion of said exhaust chamber is a shape generated by a smoothly connected line consisting of at least one straight line segment and at least one circular arc subtending angles of at least 140 degrees;
• and
• at least one circular arc forming said vertical cross-sectional shape of said inner wall of said conical portion has a radius of curvature within the range of 0.9 times to 1.8 times the blade length of said last-stage turbine rotor blades, or it has a central angle β of at least 45 degrees.