Turbine rotor, turbine, and method for removing seal plate

1. A method for removing a seal plate of a turbine rotor, the turbine rotor including:

a rotor shaft part extending in an axial direction;

a plurality of blades secured to an outer periphery of the rotor shaft part;

for each of the blades:

a seal plate facing a blade root of one of the blades on at least one side in the axial direction of the blade root, the seal plate being configured to be fitted into a groove and to seal off a flow of gas in the axial direction, the groove being defined in a platform of the one of the blades so as to be recessed toward an outer side in a radial direction and to extend in a peripheral direction;

a locking plate on an inner side in the radial direction of the seal plate, the locking plate being engaged with an end portion on the inner side in the radial direction of the seal plate with both the locking plate and the end portion on the inner side in the radial direction of the seal plate partially overlapping each other in the radial direction; and

a protrusion portion that projects toward the outer side in the radial direction on an end portion on the outer side in the radial direction of the seal plate, the method comprising:

forming a blind hole in advance that allows a removing tool to be inserted therein in a first surface of the seal plate opposite a second surface of the seal plate that faces the blade root;

removing the locking plate; and

removing the seal plate by inserting the removing tool into the blind hole and operating the removing tool to move the seal plate to the inner side in the radial direction and in the peripheral direction of the turbine rotor or at least to the inner side in the radial direction,

wherein the removing the seal plate is performed by applying a force toward the inner side in the radial direction to the removing tool,

wherein an inside groove which extends in the peripheral direction is defined in the rotor shaft part so that an end portion of the inner side in the radial direction of the locking plate is inserted into the inside groove, and

wherein the removing the locking plate is performed by moving the locking plate in the peripheral direction while moving the locking plate in the axial direction.

2. The method according to claim 1 , wherein:

the turbine rotor further includes a receiving plate including a female screw hole that penetrates in the axial direction and is configured to permit screwing of a push screw, the receiving plate being configured to press the locking plate toward the seal plate in the axial direction, and

the method further comprises:

removing the push screw from the receiving plate by turning the push screw screwed into the receiving plate.

3. The method according to claim 2 , wherein:

the inside groove which extends in the peripheral direction is defined in the rotor shaft part so that the end portion of the inner side in the radial direction of the locking plate and an end portion of the inner side in the radial direction of the receiving plate are inserted into the inside groove, and

a screw operation opening which penetrates in the axial direction is made by cutting out a barrier, which defines a surface of the inside groove, from the outer side in the radial direction toward the inner side in the radial direction.

4. The method according to claim 3 , wherein

the screw operation opening is defined in the same position as a blade root groove of the blade root in the peripheral direction.

5. The method for removing a seal plate of a turbine rotor according to claim 1 , wherein the seal plate is affixed to the groove.

6. The method according to claim 1 , wherein the removing the seal plate is performed by inserting the removing tool into the blind hole of the seal plate while applying a force in a direction toward the blade root to the removing tool such that the removing tool does not pierce through the seal plate.

7. The method according to claim 1 , wherein:

the turbine rotor further comprises a receiving plate configured to press the locking plate toward the seal plate in the axial direction,

the inside groove is defined in the rotor shaft part so that the end portion of the inner side in the radial direction of the locking plate and an end portion of the inner side in the radial direction of the receiving plate are inserted into the inside groove, and

the method further comprises removing the receiving plate from the inside groove by moving the receiving plate toward the outer side in the radial direction before the removing the locking plate.

8. The method according to claim 7 , wherein:

a female screw hole that penetrates in the axial direction and is configured to permit screwing of a push screw is defined in the receiving plate, and

the method further comprises:

removing the push screw from the receiving plate by turning the push screw screwed into the receiving plate is performed before the removing the receiving plate from the inside groove.