Turbo Machine

Abstract

A turbo machine (1, 101), in particular turbine or compressor, includes a rotor (2, 102) which has at least one moving blade row (4, 104) with a plurality of moving blades (5, 105), and a stator (3) which has at least one guide vane row (6, 106) with a plurality of guide vanes (7, 107), at least one moving blade row (4, 104) having a shroud (8, 108). The shroud (8, 108) is designed to be self-supporting in such a way that it can at least partially absorb the centrifugal forces arising during operation and discharge them in the circumferential direction.

Description

[0001]This application is a Continuation of, and claims priority under 35 U.S.C. § 120 to, International application no. PCT / EP2006 / 065879, filed 31 Aug. 2006, and claims priority therethrough under 35 U.S.C. §§ 119, 365 to Swiss application nos. 01508 / 05, 01509 / 05, both filed 15 Sep. 2005, the entireties of which are incorporated by reference herein.BACKGROUND[0002]1. Field of Endeavor[0003]The present invention relates to a turbo machine, in particular a turbine or a compressor, and, moreover, relates to a shroud or shroud ring for a turbo machine.[0004]2. Brief Description of the Related Art[0005]Turbo machines, such as turbines, in particular gas turbines and steam turbines, and also compressors, include a rotor which is mounted rotatably in a fixed stator. Turbo machines of this type are also designated as rotating turbo machines. The rotor in this case regularly includes a plurality of moving blade rows which in each case include a plurality of moving blades. Correspondingly, ...

AI Technical Summary

Benefits of technology

[0009]One of numerous aspects of the present invention includes providing, for at least one moving blade row, a shroud which connects all the moving blades of a moving blade row to one another at their tip in the circumferential direction and consequently, when the turbo machine is in operation, exerts no centrifugal forces on the moving blades, but, instead, deflects and absorbs the centrifugal forces in the circumferential direction. For this purpose, a shroud is provided which is formed from a plurality of separate shroud segments, which are assigned in each case to a plurality of moving blades, or from a plurality of separate shroud plates, which are assigned in each case to a moving blade, or from a single separate shroud ring which is assigned to all the moving blades of the respective moving blade row. At the same time, the shroud ring or the respective shroud segment or the respective shroud plate is fastened to one or to a plurality of moving blades in a radial direction. In this case, this fastening is implemented by non-destructively releasable anchorings. Thus, in a turbo machine according to principles of the invention, it is readily possible to remove the shroud for maintenance or repair purposes, without individual moving blades having to be demounted for this purpose. This is advantageous particularly for those turbo machines which have moving blades formed integrally on the rotor or on the stator. Furthermore, such a combination affords the possibility of retrofitting the shroud, that is to say of subsequently equipping a moving blade row of a turbo machine with the shroud. Thus, in such a turbo machine, stabilization by the circumferential coupling of long moving blades and / or improved aerodynamics can subsequently be achieved.

[0010]Furthermore, the shroud ring built onto the moving blades or the respective shroud segment or the respective shroud plate is a separately produced component, thus affording the possibility of using different materials and / or different material structures for the production of the shroud, on the one hand, and for the production of the moving blades, on the other hand. For example, moving blades in gas turbines are often produced from monocrystalline superalloys and optimized in terms of radial loads. In contrast to this, the shroud may be equipped, for example, with a different elasticity and be optimized for tangential loads. Moreover, owing to the separately produced shroud formed by the shroud ring or by the shroud segments or by the shroud plates, there is the possibility of optimizing the shroud in terms of the required strength by a suitable choice of material and in terms of aerodynamics by appropriate contouring.

[0012]In this case, it is basically possible to form the anchor receptacle in the shroud and to form the fitting anchor, preferably integrally, on the respective moving blade. It is likewise possible to form the anchor receptacle on the respective moving blade and to form the associated anchor, preferably integrally, on the shroud. In a further alternative, it is possible to design the shroud and the respective moving blade with anchor receptacles lying opposite one another, so that a separate, additional anchor body, which has two anchors, can be inserted simultaneously into both anchor receptacles. With the aid of an additional anchor body of this type, the mounting and demounting of the shroud can be simplified considerably.

[0016]Furthermore, the shroud ring, configured as a separate component, can readily be designed such that it can be removed again comparatively simply. The repair or replacement of the shroud ring in the event of wear phenomena is thereby simplified. This is advantageous particularly in the case of rotor portions with integrated moving blades.

[0017]A further advantage is seen in that the shroud ring is basically retrofittable. Thus, moving blade rows of a turbo machine can subsequently be provided with a shroud in a comparatively cost-effective way, so that the advantages of a shroud, to be precise the stabilization of long moving blades and an increase in efficiency due to reduced leakages and aerodynamic optimization, can thereby be utilized.

Problems solved by technology

Furthermore, shrouds of this type lead to stabilization by virtue of the circumferential support of large blades or vanes which, because of their radial length, exhibit a certain tendency to oscillate when the turbo machine is in operation.

Insofar as the shrouds are also used as axial seals for individual blade rows, they may be exposed to increased wear, as a result of which repairs are required.

Insofar as the individual shroud plates or shroud portions, which, in the mounted state, in their entirety form the respective shroud, constitute an integral part of the associated blade, this usually being the case, high repair costs are incurred, since the entire blade has to be repaired and, if appropriate, exchanged.

When the turbo machine is in operation, in particular, large moving blades which are comparatively long in the radial direction may be distorted due to the flow forces and centrifugal forces which arise.

Since the anchor and the associated anchor receptacle necessarily have to be oriented parallel to one another for mounting, distortion leads to the tilting or jamming of the anchor in its anchor receptacle.

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