Method and apparatus for eliminating thermal bowing and axial thrust loads of steam turbine rotors
First Claim
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1. A steam turbine comprising:
- a rotatable component including a rotor shaft and a non-rotatable component about said rotatable component;
a brush seal carried by said non-rotatable component for sealing engagement with the rotatable component;
said rotatable component including a plurality of buckets having bucket dovetails for connection with complementary dovetails on a wheel of said rotatable component;
means for inhibiting non-uniform circumferential heat transfer to the rotatable component thereby to eliminate or minimize bow of the rotatable component due to frictional contact between the brush seal and rotatable component;
said inhibiting means including an axially extending platform on each said bucket dovetail in frictional engagement with said brush seal at a location spaced radially outwardly of an outer diameter of the rotor shaft; and
a labyrinth seal carried by said non-rotatable component including at least one tooth extending between said non-rotatable component and said platform spaced generally radially outwardly from an outer diameter of said rotor shaft.
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Abstract
In a steam turbine, a combined brush and labyrinth seal is provided between a diaphragm web and axial projecting platforms on bucket dovetails at a location spaced radially outwardly of the outer diameter of the rotor. The downstream axially adjacent bucket dovetails also have platforms serving as complementary sealing surfaces to labyrinth teeth formed on the web. By locating the combined labyrinth and brush seal radially outwardly of the outer diameter of the shaft, thermal bowing of the rotor is eliminated. By providing backup labyrinth seals at the same radial location, axial thrust loads are eliminated in the event of brush seal failure.
55 Citations
8 Claims
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1. A steam turbine comprising:
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a rotatable component including a rotor shaft and a non-rotatable component about said rotatable component;
a brush seal carried by said non-rotatable component for sealing engagement with the rotatable component;
said rotatable component including a plurality of buckets having bucket dovetails for connection with complementary dovetails on a wheel of said rotatable component;
means for inhibiting non-uniform circumferential heat transfer to the rotatable component thereby to eliminate or minimize bow of the rotatable component due to frictional contact between the brush seal and rotatable component;
said inhibiting means including an axially extending platform on each said bucket dovetail in frictional engagement with said brush seal at a location spaced radially outwardly of an outer diameter of the rotor shaft; and
a labyrinth seal carried by said non-rotatable component including at least one tooth extending between said non-rotatable component and said platform spaced generally radially outwardly from an outer diameter of said rotor shaft. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A steam turbine comprising:
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a rotatable shaft including a plurality of circumferentially spaced buckets at each of axially spaced locations therealong forming the buckets of adjacent stages of the turbine;
a plurality of non-rotating partitions between the buckets of said adjacent stages including inner webs extending radially inwardly of a steam flowpath through the buckets and partitions;
said buckets having bucket dovetails for connecting with complementary dovetails on wheels of said shaft;
a brush seal carried by said inner webs;
means for inhibiting non-uniform circumferential heat transfer to the rotatable shaft thereby to eliminate or minimize bow of the rotatable shaft due to frictional contact between the brush seal and rotatable shaft;
said inhibiting means including a platform extending axially from each said bucket dovetail with portions of said platform lying radially inwardly of said inner webs and in radial alignment with portions of said inner webs, said brush seal extending from said inner web portions in frictional engagement with said platform portions in radial alignment therewith and at a location spaced radially outwardly of an outer diameter of said rotatable shaft; and
a labyrinth seal carried by said inner web including at least one tooth extending between said inner web portions and said platform portions and spaced generally radially outwardly from an outer diameter of said rotor shaft. - View Dependent Claims (8)
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Specification