STEAM TURBINE CASING SYSTEM

• US 20110097201A1
• Filed: 10/28/2010
• Published: 04/28/2011
• Est. Priority Date: 10/28/2009
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (GE Aerospace)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: GAFNER, Silvia, BOXHEIMER, Ludwig
• Granted Patent: US 8,834,110 B2
• Time in Patent Office: Days
• US Class Current: 415/200
• CPC Class Codes: F01D 25/26 Double casings; Measures against temperature strain in casings
• CPC Class Codes: F05D 2220/31 in steam turbines

Abstract

The disclosure relates to a steam turbine outer casing that can be at least partially cast out of a first material and has a plurality of support regions adapted to support an inner casing. The outer casing can be at least one support region that has a metal insert, made of a second material, with a flaring portion for retaining the metal insert in the casting of the outer casing. The second material has a greater hot strength than the first material. The support region can include a guide for limiting the movement of the inner casing in the outer casing.

Claims

1. A steam turbine casing system, comprising:

an outer casing having a casting made of a first material and having a support region; and

an inner casing, enclosed by the outer casing, for enclosing a rotor, the inner casing including a contact surface in contact with the support region, wherein the support region comprises;

a metal insert, made of a second material with a greater hot strength than the first material, that has an encased surface encased in the casting, wherein the encased surface includes, relative to a radial outward direction (ROD), a flaring portion that flares at least one of axially and circumferentially;

a support surface, in contact with the contact surface, configured in conjunction with the contact surface to maintain a separation between the inner casing and the casting; and

a guide for guiding the contact surface over the support surface.

2. The steam turbine casing system of claim 1, wherein the contact surface comprises:

a boss.

3. The steam turbine casing system of claim 2, wherein the metal insert comprises:

two side walls that form the guide and a channel, adapted to receive the contact surface boss, the contact surface boss including a base as the support surface.

4. The steam turbine casing system of claim 3, wherein the channel extends in an axial direction to enable axial movement of the contact surface boss when received in the channel.

5. The steam turbine casing system of claim 3, wherein a radial length of the contact surface boss, relative to a radial depth of the channel is a means for maintaining separation between the inner casing and the casting.

6. The steam turbine system of claim 1, wherein the guide is a radially inward extending boss.

7. The steam turbine casing system of claim 1, wherein the first material is nodular cast iron.

8. The steam turbine casing system of claim 1, wherein the second material is one of St460TS or St12T.

9. The steam turbine casing system of claim 4, wherein a radial length of the contact surface boss, relative to a radial depth of the channel is a means for maintaining separation between the inner casing and the casting.

10. The steam turbine casing system of claim 2, wherein the first material is nodular cast iron.

11. The steam turbine casing system of claim 3, wherein the first material is nodular cast iron.

12. The steam turbine casing system of claim 4, wherein the first material is nodular cast iron.

13. The steam turbine casing system of claim 5, wherein the first material is nodular cast iron.

14. The steam turbine casing system of claim 6, wherein the first material is nodular cast iron.

15. The steam turbine casing system of claim 2, wherein the second material is one of St460TS or St12T.

16. The steam turbine casing system of claim 3, wherein the second material is one of St460TS or St12T.

17. The steam turbine casing system of claim 4, wherein the second material is one of St460TS or St12T.

18. The steam turbine casing system of claim 5, wherein the second material is one of St460TS or St12T.

19. The steam turbine casing system of claim 6, wherein the second material is one of St460TS or St12T.

20. The steam turbine casing system of claim 7, wherein the second material is one of St460TS or St12T.