Turbine

Abstract

The present invention relates to a turbine having a housing (11) and a rotor (12), the housing (11) being provided with a plurality of rows of guide vanes (13) and the rotor (12) being provided with a plurality of rows of rotor blades (14). On the housing (11), there is a guide ring (18) which is provided axially between in each case two rows of guide vanes (13), which guide ring, together with the associated row of rotor blades (14), delimits a gap (21). According to the invention, the guide ring (18) is adjustable in order to change the gap (21). The size of the gap (21) can then be predetermined by adjusting the guide ring (18) and can be optimized according to the specific application.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to EP/01107256.8, filed Mar. 23, 2001 under the European Patent Convention and which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to a turbine having a housing and a rotor, the housing being provided with a plurality of rows of guide vanes and the rotor being provided with a plurality of rows of rotor blades, and a guide ring being provided on the housing, in the axial direction between in each case two rows of guide vanes, which guide ring, together with the associated row of rotor blades, delimits a gap.

BACKGROUND OF THE INVENTION

[0003] In known turbines, the gap or its size is thermally regulated. For this purpose, the housing is cooled to a considerably greater extent than necessary in the region of the rotor blades. This intensified cooling contracts the housing, so that the gap is reduced. The cooling medium, generally cooling air, is taken from a compressor assigned to the turbine. It can then no longer be utilized for combustion. For this reason, both the output and efficiency of the turbine fall.

[0004] Therefore, it is an object of the present invention to allow the gap to be changed by simple means without the output and efficiency being impaired.

[0005] According to the invention, this object is achieved, in a turbine of the type described in the introduction, by the fact that the guide ring can be adjusted in order to change the gap.

[0006] In view of the mechanical adjustability of the guide ring, thermal regulation is no longer required. Therefore, the consumption of cooling medium can be drastically reduced. The guide ring is adjusted in order to change the gap. Since, in general, the guide ring is designed as a separate component, which is provided between in each case two rows of guide vanes, the increased structural outlay required is very low. The adjustment can take place highly accurately and with a minimal time delay. Therefore, the gap can be adapted even to rapidly changing boundary conditions without any difficulty.

[0007] Advantageous configurations and refinements of the invention will emerge from the dependent claims.

[0008] According to a first advantageous configuration, the guide ring can be adjusted in the axial direction of the turbine. Since the housing of the turbine is generally conical, the adjustment in the axial direction achieves the desired change in the gap. There is no need to change the circumference of the guide ring. However, according to a second advantageous configuration, the guide ring may also be designed to be adjustable in the radial direction.

[0009] In the first configuration, the guide ring advantageously has at least one guide face, which runs parallel to an axis of rotation of the rotor. This guide face is in contact with at least one stationary supporting surface. The supporting surface may in this case be provided directly on the housing or on a component which is secured to the housing. The supporting surface also runs parallel to the axis of rotation of the rotor. The guide ring advantageously has two guide faces of this type, which are in contact with associated supporting surfaces. It is ensured that the guide ring is adjustable only in the axial direction parallel to the axis of rotation of the rotor. Unintended radial adjustment of the guide ring is reliably avoided.

[0010] The supporting surface may be formed in particular on platforms of the guide vanes which adjoin the guide ring. There is then no need to additionally machine the housing.

[0011] The guide ring is advantageously arranged on a guide-ring carrier, which can be adjusted with respect to the housing. The guide-ring carrier ensures that the guide ring is held reliably. Undefined movements of the guide ring are reliably ruled out. The guide-ring carrier may simply be inserted into a corresponding recess in the housing and for its part may be suitably guided in this recess. It can therefore both be provided from the outset in new turbines and be retrofitted to existing turbines.

[0012] According to an advantageous refinement, the guide-ring carrier has at least one groove, into which an eccentric which can be driven rotatably engages for adjustment purposes. Suitable selection of the materials for the guide-ring carrier and the eccentric makes it possible to dispense with lubrication. The adjustment can then be designed for high temperatures. It operates rapidly and reliably and is easy to produce.

[0013] In an advantageous refinement, a cooling chamber for cooling the guide ring is provided between the guide ring and the guide-ring carrier. The cooling chamber is acted on by a cooling medium via suitable connections. Therefore, the guide ring can be used even at high temperatures.

[0014] The guide ring is advantageously sealed with respect to the housing by at least one seal, in order to minimize or completely prevent losses of cooling medium. As was stated in the introduction, the cooling medium is taken from the compressor. The more cooling medium is removed, the lower the efficiency becomes. The at least one seal can therefore minimize the consumption of coolant and therefore produce a higher efficiency.

[0015] The seal may in this case be designed as a labyrinth seal or as an elastically deformable seal. When an elastically deformable seal is used, the seal advantageously consists of a metallic material which is suitable for high temperatures.

[0016] The guide ring is advantageously accommodated in an insert and sealed with respect to this insert. The seals then run between the insert and the guide ring. The insert can be preassembled with the seals and the guide ring and inserted into the recess in the housing. Therefore, the design, production and assembly can be made simple even when using seals.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The invention is explained in more detail below with reference to exemplary embodiments, which are diagrammatically illustrated in the drawing. Throughout the description, identical reference symbols are used for similar and functionally identical components. In the drawing:

[0018] FIG. 1 shows a diagrammatic longitudinal section through a turbine;

[0019] FIG. 2 shows an enlarged illustration of detail X from FIG. 1;

[0020] FIGS. 3 and 4 show different positions of the guide ring in a view which is similar to that shown in FIG. 2;

[0021] FIG. 5 diagrammatically depicts the adjustability of the guide ring in longitudinal section;

[0022] FIG. 6 shows an enlarged illustration of detail Y from FIG. 5;

[0023] FIG. 7 shows an enlarged illustration of detail Z from FIG. 5;

[0024] FIG. 8 shows a plan view of a guide ring in the direction indicated by arrow VIII in FIG. 5; and

[0025] FIG. 9 illustrates a further exemplary embodiment, in a view similar to that shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] FIG. 1 shows a diagrammatic longitudinal section through a gas turbine 10 having a housing 11 and a rotor 12. The housing 11 is provided with guide vanes 13, and the rotor 12 is provided with rotor blades 14. Hot gas flows through the gas turbine 10 in the direction indicated by arrow 15, causing the rotor 12 to rotate about its axis of rotation 16, in the direction indicated by arrow 17. Both the guide vanes 13 and the rotor blades 14 are arranged in rows. A guide ring 18 is arranged between in each case two rows of guide vanes 13. The guide ring 18 is advantageously of multipart design.

[0027] FIG. 2 shows an enlarged illustration of the detail X from FIG. 1, and FIGS. 3 and 4 show different positions of the guide ring 18. The housing 11 widens in the direction indicated by arrow 15. Therefore, by adjusting the guide ring 18 in the axial direction in accordance with the directions indicated by arrows 19, 20, it is possible to change the size of a gap 21 between the guide ring 18 and the free end of the rotor blades 14. Adjustment to the left, in the direction indicated by arrow 19, into position 18′ leads to an enlarged gap 21′. This adjustment is illustrated in FIG. 3. If, by contrast, the guide ring is displaced in the direction indicated by arrow 20, into its position 18″ illustrated in FIG. 4, the size of the gap 21″ is reduced. There is no need to change the diameter of the guide ring. This is diagrammatically indicated by a dashed line 22, connecting FIGS. 3 and 4.

[0028] FIG. 5 diagrammatically depicts the adjustability of the guide ring 18 in longitudinal section. The guide ring 18 is secured to a guide-ring carrier 23, which is accommodated in a recess 24 in a guide-vane carrier 30, and is supported on platforms 33 of adjacent guide vanes 13. The guide-vane carrier 30 is connected to the housing 11 in a suitable manner which is not illustrated in more detail. To adjust the guide-ring carrier 23, a shaft 25, which can be driven rotatably, in a bore 32 and an eccentric 26 are provided. As soon as the shaft 25 is rotated in the direction indicated by arrow 31, the eccentric 26 causes the guide-ring carrier 23 to be displaced in the directions indicated by arrows 19, 20. In this case, the eccentric 26 is supported on lateral projections 37, 38 of the guide-ring carrier 23.

[0029] With the adjustability which is provided according to the invention, there is also provision for the guide ring 18 to be cooled. A cooling medium, for example cooling air which has been taken from a compressor, is passed through the housing 11 and the guide-vane carrier 30, via a bore 27, into the recess 24. For its part, the guide-ring carrier 23 has a bore 28 into which the cooling medium can pass. The bore 28 leads to a chamber 29 which, toward the rotor 12, is delimited by the guide ring 18. Therefore, effective cooling of the guide ring 18 is achieved by applying the cooling medium to the chamber 29. Details of the adjustment of the guide ring 18 are illustrated in FIGS. 6 to 8. In this case, FIGS. 6 and 7 show an enlarged illustration of the details Y, Z from FIG. 5. The guide ring 18 has guide faces 34 which run parallel to the axis of rotation 16 of the rotor. These guide faces are in contact with associated supporting surfaces 35 on the platforms 33. The supporting surfaces 35 also run parallel to the axis of rotation 16. This ensures that the guide ring 18 is reliably guided in the axial direction and adjustment takes place only in the directions indicated by arrows 19, 20. There is no possibility of an unintended radial displacement of the guide ring 18. The adjustment is effected by rotation of the eccentrics 26, which engage in a groove 36 between the projections 37, 38 on the top side of the guide-ring carrier 23. The bores 28 used for cooling are arranged between the eccentrics 26.

[0030] FIG. 9 shows a further exemplary embodiment of the invention, in a view which is similar to that shown in FIG. 5. An insert 40 with side parts 41, 42 is inserted into the recess 24. In the exemplary embodiment illustrated, a ring 43 with an opening 44, to which the side parts 41, 42 are secured, is additionally provided. The insert 40 can therefore be preassembled and then fixed in the recess 24. As well as the three-part design illustrated, a single-part design of the insert 40 is also possible.

[0031] The guide-ring carrier 23 is accommodated in the insert 40 and can be displaced in the directions indicated by arrows 19, 20 by means of the shaft 25 and the eccentrics 26. It is guided by means of elements which are not illustrated in more detail.

[0032] To prevent losses of cooling medium, the guide-ring carrier 23 is sealed by means of seals 45, 46. The seals 45, 46 are arranged between the guide-ring carrier 23 and the side parts 41 of the insert 40. The seal 45 is in this case designed as a labyrinth seal. The seal 46 is elastically deformable. It consists of an elastic material which is designed for the temperatures which occur during operation of the turbine 10.

[0033] For production, the guide ring 18 is secured to the guide-ring carrier 23. Then, the seals 45, 46 are prefitted and the insert 40 is put in place. Then, the guide-ring carrier 23 is inserted, together with the insert 40 and the seals 45, 46, into the recess 24.

[0034] The subject matter of the present invention makes it possible to change the gap 21 easily and without complications by adjusting the guide ring 18. This adjustment arrangement can also be retrofitted to existing turbines 10. Changing the gap 21 results in optimum matching to the prevailing operating conditions. There is no need for increased consumption of the cooling medium, as has been the case in previous solutions. Therefore, the efficiency of the turbine 10 is considerably improved.

Claims

1. A turbine comprising a housing and a rotor, the housing being provided with a plurality of rows of guide vanes and the rotor being provided with a plurality of rows of rotor blades, and a guide ring being provided on the housing in the axial direction between in each case two rows of guide vanes, the guide ring together with the associated row of rotor blades delimiting a gap characterized in that the guide ring can be adjusted in order to change the gap.

2. The turbine as claimed in claim 1, wherein the guide ring can be adjusted in the axial direction of the turbine.

3. The turbine as claimed in claim 2, wherein the guide ring has at least one guide face, which runs parallel to an axis of rotation of the rotor and is in contact with at least one stationary supporting surface.

4. The turbine as claimed in claim 3, wherein the at least one supporting surface is formed on platforms of the guide vanes which adjoin the guide ring.

5. The turbine as claimed in claim 1, wherein the guide ring is arranged on a guide-ring carrier, which can be adjusted with respect to the housing.

6. The turbine as claimed in claim 5, wherein the guide-ring carrier has at least one groove, into which an eccentric which can be driven rotatably engages for adjustment purposes.

7. The turbine as claimed in claim 5, wherein a cooling chamber for cooling the guide ring is provided between the guide ring and the guide-ring carrier.

8. The turbine as claimed in claim 1, characterized in that the guide ring is sealed with respect to the housing by at least one seal in order to minimize losses of cooling medium.

9. The turbine as claimed in claim 8, wherein the seal is designed as a labyrinth seal or as an elastically deformable seal.

10. The turbine as claimed in claim 8, wherein the guide ring is accommodated in an insert and is sealed with respect to this insert.

11. A turbine adapted for use in a land-based power generation plant, comprising: a housing having a plurality of rows of guide vanes; a rotor having a plurality of rows of rotor blades; and a guide ring provided on the housing in the axial direction between two rows of guide vanes, the guide ring and the associated row of rotor blades forming a gap wherein the guide ring can be adjusted in order to change the size of the gap.

12. The turbine as claimed in claim 11, wherein the guide ring can be adjusted in the axial direction of the turbine.

13. The turbine as claimed in claim 12, wherein the guide ring has at least one guide face, which runs parallel to an axis of rotation of the rotor and is in contact with at least one stationary supporting surface.

14. The turbine as claimed in claim 13, wherein the at least one supporting surface is formed on platforms of the guide vanes which adjoin the guide ring.

15. The turbine as claimed in claim 11, wherein the guide ring is arranged on a guide-ring carrier, which can be adjusted with respect to the housing.

16. The turbine as claimed in claim 15, wherein the guide-ring carrier has at least one groove, into which an eccentric which can be driven rotatably engages for adjustment purposes.

17. The turbine as claimed in claim 15, wherein a cooling chamber for cooling the guide ring is provided between the guide ring and the guide-ring carrier.

18. The turbine as claimed in claim 11, characterized in that the guide ring is sealed with respect to the housing by at least one seal in order to minimize losses of cooling medium.

19. The turbine as claimed in claim 18, wherein the seal is designed as a labyrinth seal or as an elastically deformable seal.

20. A turbine adapted for use in a land-based power generation plant, comprising: a housing having a plurality of rows of guide vanes; a rotor in operative association with the guide vanes; a guide ring provided on the housing between two rows of guide vanes, the guide ring and the associated row of rotor blades forming an adjustable gap.