Steam turbine

Patent metadata

Field	Value
Publication number	US-12203383-B2
Application number	US-202218702574-A
Country	US
Kind code	B2
Filing date	Nov 30, 2022
Priority date	Dec 15, 2021
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

A steam turbine according to at least one embodiment of the present disclosure includes an outer casing. The steam turbine according to at least one embodiment of the present disclosure includes an annular member, which is a single member provided radially inward of the outer casing, and formed in the annular member are a seal region in which a sealing device for sealing a gap between said member and the outer peripheral surface of a rotor is located, a rear-stage-stator-vane-holding region where a rear-stage stator vane is held, and an inner casing region connecting the seal region and the rear-stage-stator-vane-holding region. The steam turbine according to at least one embodiment of the present disclosure includes a front-stage vane ring that is attached to the annular member and that holds a front-stage stator vane.

First claim

The invention claimed is:

1. A steam turbine comprising:
an outer casing;
an annular member which is a single member provided on a radial inner side of the outer casing, and which is formed with a seal region in which a sealing device for sealing a gap between the member and an outer peripheral surface of a rotor is disposed, a rear-stage stator vane holding region that holds a rear-stage stator vane, and an inner casing region that connects the seal region and the rear-stage stator vane holding region; and
a front-stage vane ring that is mounted on the annular member and that holds a front-stage stator vane,
wherein the seal region and the front-stage vane ring form a first cavity to which first steam is supplied, between the seal region and the front-stage vane ring.

2. The steam turbine according to claim 1 ,
wherein the annular member includes an upper half portion and a lower half portion joined together in a horizontal plane,
a plurality of joining bolts that join the upper half portion and the lower half portion are provided, and
the plurality of joining bolts include a first joining bolt disposed within a range in which the seal region is formed along an axial direction, and a second joining bolt that is disposed on a radial outer side with respect to the first joining bolt and whose position in the axial direction overlaps with the first joining bolt.

3. The steam turbine according to claim 1 , wherein the front-stage vane ring and the rear-stage stator vane holding region form a second cavity to which second steam is supplied, between the front-stage vane ring and the rear-stage stator vane holding region.

4. The steam turbine according to claim 3 , wherein the front-stage vane ring has a protrusion portion that protrudes toward an axial downstream side at an end portion that is located on a radial inner side with respect to the second cavity and faces the rear-stage stator vane holding region.

5. The steam turbine according to claim 1 , wherein a central axis of a pipe stand for supplying first steam to a first stator vane that is located on a most upstream side in an axial direction is located on an axial downstream side with respect to the first stator vane.

6. The steam turbine according to claim 1 , wherein the front-stage vane ring has an inclined surface that faces an axial upstream side toward the radial inner side.

7. The steam turbine according to claim 6 , wherein the inclined surface linearly extends to face the axial upstream side toward the radial inner side, in a cross section along a radial direction and an axial direction.

8. The steam turbine according to claim 6 , wherein an axial wall thickness of the front-stage vane ring increases toward the radial inner side between an end surface on an axial downstream side of the front-stage vane ring and the inclined surface.

9. The steam turbine according to claim 1 , wherein the number of the stator vanes that are held by the front-stage vane ring is smaller than the number of the stator vanes that are held by the rear-stage stator vane holding region.

10. The steam turbine according to claim 1 ,
wherein the steam turbine is a medium-high pressure integrated type steam turbine which includes a high-pressure section and a medium-pressure section, and
the high-pressure section includes the annular member and the front-stage vane ring.

11. The steam turbine according to claim 1 ,
wherein the seal region and the front-stage vane ring form a first cavity to which first steam is supplied, between the seal region and the front-stage vane ring, and
the first steam is supercritical pressure steam.

12. A steam turbine comprising:
an outer casing;
an annular member which is a single member provided on a radial inner side of the outer casing, and which is formed with a seal region in which a sealing device for sealing a gap between the member and an outer peripheral surface of a rotor is disposed, a rear-stage stator vane holding region that holds a rear-stage stator vane, and an inner casing region that connects the seal region and the rear-stage stator vane holding region; and
a front-stage vane ring that is mounted on the annular member and that holds a front-stage stator vane,
wherein a central axis of a pipe stand for supplying first steam to a first stator vane that is located on a most upstream side in an axial direction is located on an axial downstream side with respect to the first stator vane.

13. A steam turbine comprising:
an outer casing;
an annular member which is a single member provided on a radial inner side of the outer casing, and which is formed with a seal region in which a sealing device for sealing a gap between the member and an outer peripheral surface of a rotor is disposed, a rear-stage stator vane holding region that holds a rear-stage stator vane, and an inner casing region that connects the seal region and the rear-stage stator vane holding region; and
a front-stage vane ring that is mounted on the annular member and that holds a front-stage stator vane,
wherein the steam turbine is a medium-high pressure integrated type steam turbine which includes a high-pressure section and a medium-pressure section, and
the high-pressure section includes the annular member and the front-stage vane ring.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Yamashita Shoki
• Yoshifuji Takakazu

Classifications

• F05D2240/55

  Seals · CPC title

• F05D2240/14

  Casings or housings protecting or supporting assemblies within · CPC title

• F05D2240/12

  Fluid guiding means, e.g. vanes · CPC title

• F05D2220/31

  in steam turbines · CPC title

• F01D11/08

  for sealing space between rotor blade tips and stator (specially-shaped blade tips therefor F01D5/20) · CPC title