Apparatus and method for controlling leakage in steam turbines

Abstract

An apparatus for routing fluid in a steam turbine is provided. The steam turbine includes a stage comprising a plurality of buckets secured to a rotor. The rotor is configured to rotate in response to a first volume of fluid flowing from an inlet passageway past the plurality of buckets. The apparatus includes a member having a fluid passageway extending therethrough. The fluid passageway includes a first end in fluid communication with a discharge side of the stage of the steam turbine. A second volume of fluid comprising a portion of the first volume of fluid is received into the fluid passageway at the discharge side of the stage and is discharged out of an outlet of the fluid passageway. The outlet is in fluid communication with a region between an upstream side of the stage and a sealing member disposed against the rotor. The region receives a third volume of leakage fluid from the upstream side of the stage. The second volume of fluid discharged out of the outlet both reduces the third volume of leakage fluid entering the region and increases the first volume of fluid flowing past the plurality of buckets to increase an amount of torque of the rotor.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a portion of a pressurized section of a steam turbine;

FIG. 2 is an enlarged sectional view of a portion of the pressurized section of FIG. 1 showing fluid flow paths within the pressurized section;

FIG. 3 is a sectional view illustrating a first fluid passageway and a second fluid passageway for routing a portion of a fluid in the pressurized section of FIG. 1 in accordance with an exemplary embodiment of the present invention;

FIG. 4 is an enlarged view of a transition conduit utilized in the steam turbine of FIG. 3;

FIG. 5 is a sectional view illustrating a fluid passageway disposed at an exterior portion of a shell member for routing a portion of a fluid in the pressurized section of FIG. 1 in accordance with an alternative exemplary embodiment of the present invention;

FIG. 6 is an enlarged view of a transition conduit utilized in the steam turbine of FIG. 5;

FIG. 7 is an enlarged view of an end packing head having a discharge outlet in accordance with an alternative exemplary embodiment of the present invention; and

FIG. 8 is a sectional view illustrating a fluid passageway disposed in a stationary guide member for routing a portion of a fluid in the pressurized section of FIG. 1 in accordance with an alternative exemplary embodiment of the present invention.

Claims

1. An apparatus for routing fluid in a steam turbine, the steam turbine having a stage comprising a plurality of buckets secured to a rotor, the rotor being configured to rotate in response to a first volume of fluid flowing from an inlet passageway past the plurality of buckets, the apparatus comprising: a member having a fluid passageway extending therethrough, a first end of the fluid passageway being in fluid communication with a discharge side of the stage of the steam turbine, wherein a second volume of fluid comprising a portion of the first volume of fluid is received into the fluid passageway at the discharge side of the stage and is discharged out of an outlet of the fluid passageway, the outlet being in fluid communication with a region between an upstream side of the stage and a sealing member disposed against the rotor, the region receiving a third volume of leakage fluid from the upstream side of the stage; andwherein the second volume of fluid discharged out of the outlet both reduces the third volume of leakage fluid entering the region and increases the first volume of fluid flowing past the plurality of buckets to increase an amount of torque of the rotor.

2. The apparatus as in claim 1, wherein the outlet is configured to direct the second volume of fluid in a direction that is not toward a periphery of the rotor and the second volume of fluid is steam.

3. The apparatus as in claim 1, wherein the sealing member is integral with the member.

4. An apparatus for routing fluid in a steam turbine, the steam turbine having a stage comprising a plurality of buckets secured to a rotor, the rotor being configured to rotate in response to a first volume of fluid flowing from an inlet passageway past the plurality of buckets, the apparatus comprising: a first member having a first fluid passageway extending therethrough, the first fluid passageway being in fluid communication with a discharge side of the stage of the steam turbine, wherein a second volume of fluid comprising a portion of the first volume of fluid is received into the first fluid passageway from the discharge side of the stage;a second member having a second fluid passageway extending therethrough that is in fluid communication with the first fluid passageway, wherein the second volume of fluid is routed from the first fluid passageway into the second fluid passageway and is discharged out of an outlet of the second fluid passageway, the outlet being in fluid communication with a region between an upstream side of the stage and a sealing member disposed against the rotor, the region receiving a third volume of leakage fluid from the upstream side of the stage; andwherein the second volume of fluid discharged out of the outlet both reduces the third volume of leakage fluid entering the region and increases the first volume of fluid flowing past the plurality of buckets to increase an amount of torque of the rotor.

5. The apparatus as in claim 4, wherein the outlet is configured to direct the second volume of fluid in a direction that is not toward a periphery of the rotor and the second volume of fluid is steam.

6. The apparatus as in claim 4, further comprising a transition conduit, the transition conduit being configured to route the second volume of fluid from the first fluid passageway into the second fluid passageway, the transition conduit having first and second end portions, the first end portion being disposed in the first fluid passageway, the second end portion being disposed in the second fluid passageway, the first end portion having a sealing portion configured to prevent fluid flow between an outer surface of the first end portion and an inner surface of the first fluid passageway, the second end portion having a sealing portion configured to prevent fluid flow between an outer surface of the second end portion and an inner surface of the second fluid passageway.

7. The apparatus as in claim 6, wherein at least one of the sealing portions is further configured to provide a zero clearance fit between the outer surface of the first end portion and the inner surface of the first fluid passageway or between the outer surface of the second end portion and the inner surface of the second fluid passageway, during an operating condition of the steam turbine.

8. The apparatus as in claim 6, wherein at least one of the sealing portions further comprises a surface treatment configured so the transition conduit can be disposed into and removed from the first and second fluid passageways with reduced galling between the outer surface of the first end portion and the inner surface of the first fluid passageway or between the outer surface of the second end portion and the inner surface of the second fluid passageway.

9. The apparatus as in claim 4, wherein the first fluid passageway comprises a first passageway portion, a second passageway portion, and a third passageway portion, the first passageway portion extending through the first member, a first end of the first passageway portion being in fluid communication with the discharge side of the stage and a second end of the first passageway portion being disposed at an exterior surface of the first member, the second passageway portion being defined by an external conduit configured to provide fluid communication between the first passageway portion and the third passageway portion, the third passageway portion extending through the first member from the exterior surface and being in fluid communication with the second fluid passageway.

10. The apparatus as in claim 9, further comprising a transition conduit, the transition conduit being configured to route the second volume of fluid from the external conduit into the third passageway portion, the transition conduit having first and second end portions, the first end portion being disposed in the external conduit, the second end portion being disposed in the third passageway portion, the first end portion having a sealing portion configured to prevent fluid flow between an outer surface of the first end portion and an inner surface of the external conduit, the second end portion having a sealing portion configured to prevent fluid flow between an outer surface of the second end portion and an inner surface of the third passageway portion.

11. The apparatus as in claim 9, further comprising a transition conduit, the transition conduit being configured to route the second volume of fluid from the external conduit into the second fluid passageway, the transition conduit having first and second end portions, the first end portion being disposed in the external conduit, the second end portion being disposed in the second fluid passageway, the first end portion having a sealing portion configured to prevent fluid flow between an outer surface of the first end portion and an inner surface of the external conduit, the second end portion having a sealing portion configured to prevent fluid flow between an outer surface of the second end portion and an inner surface of the second fluid passageway.

12. The apparatus as in claim 11, wherein at least one of the sealing portions is further configured to provide a zero clearance fit between the outer surface of the first end portion and the inner surface of the external conduit or between the outer surface of the second end portion and the inner surface of the second fluid passageway, during an operating condition of the steam turbine.

13. The apparatus as in claim 11, wherein at least one of the sealing portions further comprises a surface treatment configured so the transition conduit can be disposed into and removed from the external conduit and the second fluid passageway with reduced galling between the outer surface of the first end portion and the inner surface of the external conduit or between the outer surface of the second end portion and the inner surface of the second fluid passageway.

14. A steam turbine, comprising: a rotor rotatably received in the steam turbine;a plurality of stages being disposed in a facing spaced relationship with respect to each other, each stage of the plurality of stages comprising a plurality of buckets secured to the rotor, wherein each bucket of the plurality of buckets having at least one blade secured thereto spaced apart from an adjacent blade, wherein the rotor rotates when a first volume of fluid from an inlet passageway contacts the plurality of spaced blades and the first volume of fluid flows through a first stage plurality of buckets toward a second stage plurality of buckets by passing in a downstream direction between the plurality of spaced blades of the first stage plurality buckets to a discharge side of the first stage, the discharge side of the first stage defining an area between the first stage plurality of buckets and the second stage plurality of buckets;a first member having a first fluid passageway extending therethrough, the first fluid passageway being in fluid communication with the discharge side of the first stage of the steam turbine, wherein a second volume of fluid comprising a portion of the first volume of fluid is received into the first fluid passageway from the discharge side of the first stage;a second member disposed about a portion of the rotor, the second member comprising a second fluid passageway extending therethough that is in fluid communication with the first fluid passageway, wherein the second volume of fluid is routed from the first fluid passageway into the second fluid passageway and is discharged out of an outlet of the second fluid passageway, the outlet being in fluid communication with a region between an upstream side of the first stage and a sealing member disposed against the rotor, the region receiving a third volume of leakage fluid from the upstream side of the first stage; andwherein the second volume of fluid discharged out of the outlet both reduces the third volume of leakage fluid entering the region and increases the first volume of fluid flowing past the first stage plurality buckets to increase an amount of torque of the rotor.

15. The steam turbine as in claim 14, wherein the outlet is configured to direct the second volume of fluid in a direction that is not toward a periphery of the rotor and the second volume of fluid is steam.

16. The steam turbine as in claim 14, further comprising a transition conduit, the transition conduit being configured to route the second volume of fluid from the first fluid passageway into the second fluid passageway, the transition conduit having first and second end portions, the first end portion being disposed in the first fluid passageway, the second end portion being disposed in the second fluid passageway, the first end portion having a sealing portion configured to prevent fluid flow between an outer surface of the first end portion and an inner surface of the first fluid passageway, the second end portion having a sealing portion configured to prevent fluid flow between an outer surface of the second end portion and an inner surface of the second fluid passageway.

17. The steam turbine as in claim 14, wherein the first fluid passageway comprises a first passageway portion, a second passageway portion, and a third passageway portion, the first passageway portion extending through the first member, a first end of the first passageway portion being in fluid communication with the discharge side of the stage and a second end of the first passageway portion being disposed at an exterior surface of the first member, the second passageway portion being defined by an external conduit configured to provide fluid communication between the first passageway portion and the third passageway portion, the third passageway portion extending through the first member from the exterior surface and being in fluid communication with the second fluid passageway.

18. The steam turbine as in claim 17, further comprising a transition conduit, the transition conduit being configured to provide fluid communication between the external conduit and the second fluid passageway, the transition conduit having first and second end portions, the first end portion being disposed in the external conduit, the second end portion being disposed in the second fluid passageway, the first end portion having a sealing portion configured to prevent fluid flow between an outer surface of the first end portion and an inner surface of the external conduit, the second end portion having a sealing portion configured to prevent fluid flow between an outer surface of the second end portion and an inner surface of the second fluid passageway.

19. The steam turbine as in claim 18, wherein at least one of the sealing portions is further configured to provide a zero clearance fit between the outer surface of the first end portion and the inner surface of the external conduit or between the outer surface of the second end portion and the inner surface of the second fluid passageway, during an operating condition of the steam turbine.

20. The steam turbine as in claim 18, wherein at least one of the sealing portions further comprises a surface treatment configured so the transition conduit can be disposed into and removed from the external conduit and the second fluid passageway with reduced galling between the outer surface of the first end portion and the inner surface of the external conduit or between the outer surface of the second end portion and the inner surface of the second fluid passageway.