EP1924757A1

EP1924757A1 - Cover strip comprising a detachable anchoring for a row of blades of a turbomachine

Info

Publication number: EP1924757A1
Application number: EP06793115A
Authority: EP
Inventors: Joergen Ferber; James Ritchie; Slawomir Slowik
Original assignee: Alstom Technology AG
Current assignee: General Electric Technology GmbH
Priority date: 2005-09-15
Filing date: 2006-08-31
Publication date: 2008-05-28
Also published as: WO2007031408A1; US20080298970A1

Abstract

The invention relates to a turbomachine (1, 101), in particular, a turbine or compressor, which comprises a rotor (2, 102) which comprises at least one row of mobile blades (4, 104) comprising several mobile blades (5, 105), and a stator (3), which comprises at least one row of guide blades (6, 106) comprising several guide blades (7, 107). At least one row of mobile blades (4, 104) comprises a cover strip (8, 108). According to the invention, the cover strip (8, 108) is self-supporting such that it can at least partially absorb centrifugal forces occurring during operation and can transfer them in the peripheral direction. The cover strip (8, 108) is a separately produced element which is secured to several or all of the mobile blades (5, 105) by means of at least one detachable anchoring (10) in a non-destructive manner.

Description

DECKBAND WITH LOCKABLE ANCHORAGE FOR A SHOVEL SERIES OF A FLOW MACHINE

Technical area

The present invention relates to a turbomachine, in particular a turbine or a compressor having the features of the preamble of claim 1. The invention also relates to a shroud or a shroud ring for such a turbomachine.

State of the art

Turbomachines, such as turbines, in particular gas turbines and steam turbines, as well as compressors, comprise a rotor, which is rotatably mounted in a stationary stator. Such turbomachines are also referred to as rotating turbomachines. The rotor regularly comprises several blade rows, each consisting of several blades. Accordingly, the stator typically has a plurality of rows of vanes, each consisting of a plurality of vanes.

It is basically known to provide the blade rows and / or the guide blade rows with a shroud, which has an annular arrangement in the mounted state and the free blade ends adjacent Blades within the same row of blades together. With the help of such shrouds, the aerodynamics of the respective blade row can be improved, which increases the efficiency of the turbomachine equipped therewith. In addition, such shrouds lead to a stabilization by circumferential support of large blades, which show a certain tendency to oscillate due to their radial length during operation of the turbomachine.

From GB 1 509 185 A, a blade row is known in which the individual blades are connected to one another in the region of their blade tips via shroud segments arranged therebetween.

If the shrouds are also used as axial seals for individual rows of blades, they can be exposed to increased wear, which repairs are required. If the individual cover plates or shroud sections, which in their entirety constitute the respective shroud in the mounted state, form an integral part of the associated shovel, which is the case regularly, high repair costs are incurred since the entire shovel must be repaired and possibly replaced ,

Presentation of the invention

The invention aims to remedy this situation. The invention, as characterized in the claims, deals with the problem of providing for a turbomachine of the type mentioned in an improved embodiment, which is characterized in particular by reduced operating costs and maintenance costs. This problem is solved by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea to provide for at least one row of blades a shroud that connects all the blades of a row of blades at the top in the circumferential direction with each other and thereby exert no centrifugal forces on the blades during operation of the turbomachine, but deflect the centrifugal forces in the circumferential direction and record should. For this we have provided a shroud, which is formed of a plurality of separate shroud segments, each associated with a plurality of blades, or of a plurality of separate cover plates, each associated with a blade, or from a single separate shroud ring, which is assigned to all blades of the respective blade row. At the same time, the shroud ring or the respective shroud segment or the respective cover plate is fastened to one or more rotor blades in the radial direction. This attachment is realized by means of non-destructive releasable anchors. In this way, it is readily possible in the turbomachine according to the invention, the shroud for maintenance gs or repair purposes expand without the need for individual blades to be dismantled. This is particularly advantageous for those turbomachines which have integral rotor blades or rotor blades. In addition, the feature combination according to the invention basically provides the option of retrofitting the shroud, that is, of retrofitting a shovel row with the shroud in a turbomachine. In this way, stabilization by means of circumferential coupling of long rotor blades and / or improved aerodynamics can be subsequently achieved with such a turbomachine. In addition, the attached to the blades shroud ring or the respective shroud segment or the respective cover plate is a separately manufactured component, which offers the possibility for the production of the shroud on the one hand and for the production of the blades on the other hand different materials and / or different material structures to use. For example, blades in gas turbines are often made of monocrystalline superalloys and optimized in terms of radial loads. In contrast, the shroud, for example, be equipped with a different elasticity and optimized for tangential loads. The separately produced, formed by the shroud ring or by the shroud segments or by the cover plates shroud also offers the possibility to optimize the shroud in terms of the required strength by suitable choice of material and aerodynamics by appropriate contouring.

According to an advantageous embodiment, the anchoring may comprise at least one anchor receptacle having a constant in a longitudinal direction of the anchor receptacle and radially unilaterally open receiving profile with at least one radially undercut behind. Furthermore, the anchoring can have at least one anchor with an armature profile designed to be complementary to the receiving profile, which can be inserted into the armature receptacle so that its armature profile engages with the at least one undercut of the armature receptacle. By anchoring thus a positive and particularly resilient mechanical connection between the respective blade and the shroud ring or the respective shroud segment or the respective cover plate is made. It is basically possible to form the anchor receptacle in the shroud and form the matching anchor, preferably integrally, on the respective blade. It is also possible to form the anchor receptacle on the respective blade and form the associated anchor, preferably integrally, on the shroud. In a further alternative, it is possible to form the shroud and the respective blade with opposing anchor shots, so that a separate, additional anchor body having two anchors, can be used simultaneously in both anchor shots. With the help of such an additional anchor body, the assembly and disassembly of the shroud can greatly simplify.

The use of such anchor and armature mounts leads in addition to the radial fixing of the shroud on the blades in addition to a fixation of the shroud transversely to the longitudinal direction of the anchor shots. In the case of an axially oriented anchor receptacle, this results in a fixation in the circumferential direction. If the armature receptacle is inclined relative to the axial direction, this also results in holding forces in the axial direction.

Another advantage is seen in the fact that at least elongated anchor lead in a twist of the blades in addition to a frictional fixing of the shroud on the blades. During operation of the turbomachine, in particular large rotor blades, which are comparatively long in the radial direction, can twist due to the occurring flow and centrifugal forces. Since the armature and associated anchor receptacle must necessarily be aligned parallel to one another for mounting, the twisting leads to tilting or jamming of the armature in its armature receptacle. The invention is based on an alternative embodiment based on the general idea not to form the respective shroud of several, individual blades associated cover plates or shroud sections, but from a single, all blades of the respective blade row associated shroud ring to form self-supporting and to the radially outer blade tips of the blade row is attached. The self-supporting shroud ring is designed so that it can absorb the forces occurring during operation, in particular when it is associated with a blade row, in itself, without burdening the blades. In particular, the centrifugal forces occurring during operation can absorb in themselves, without causing a significant additional radial tensile load of the blades occurs. The life of the blades is thereby increased. Likewise, the blades can be dimensioned smaller, which can be used to increase the efficiency of the turbomachine weight reduction. This is achieved by the circumferentially closed body of the shroud ring, which converts the centrifugal forces occurring in tangential tensile stresses. To be able to attach the shroud ring to the blade, the shroud ring must be a component made separately with respect to the blades. The separate production of the shroud ring allows the use of a material which differs from that of the rotor blades and / or a material structure which differs from that of the rotor blades. For example, the shroud ring can be optimized in the direction of a tensile load in the circumferential direction, while the blades are usually optimized with respect to a tensile load in the radial direction.

In addition, the shroud ring designed as a separate component can readily be designed such that it can be removed comparatively easily can be. This simplifies the repair or replacement of the shroud ring in the event of signs of wear. This is particularly advantageous in rotor sections with integrated blades.

Another advantage is seen in that the shroud ring is basically retrofitted. In this way, blade rows of a turbomachine can be subsequently provided in a comparatively cost-effective manner with a shroud, in order to use the advantages of a shroud, namely stabilization of long blades and efficiency increase by reduced leakage and aerodynamic optimization.

In a preferred embodiment, the shroud ring may be mounted to the blades so as to be radially free with respect to the blades. That is, the shroud ring is not fixed to the blades in the radial direction, but is relatively freely or loosely arranged relative thereto. In this way, for example, thermally induced stresses can be reduced. Of particular advantage is this design when using the shroud ring at a blade row. The centrifugal forces occurring during operation force the shroud ring radially outward. Due to the degree of freedom provided in the radial direction, the shroud ring can basically lift off from the associated rotor blades in the radial direction, without any tensile forces being transmitted between the pressure beltring and the rotor blades. With regard to the centrifugal forces, the blades are thus decoupled from the shroud ring.

In this case, depending on the design of the coupling between the shroud ring and the blades - and a coupling of the blades in the circumferential direction to avoid the vibration excitation can still be guaranteed. Other important features and advantages of the turbomachine according to the invention will become apparent from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

Brief description of the drawings

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components. Show, in each case schematically,

Fig. 1 is a greatly simplified, basic cross-section through a

Turbomachine in the area of a blade row,

2 is a view in the radial direction in the region of a blade according to an arrow III in Fig. 1,

3 is a sectional view of the blade in the region of a shroud according to section lines IV in Fig. 2,

Fig. 4 is a view in the axial direction of the blade in the region of

Shrouds corresponding to an arrow V in Fig. 2,

Fig. 5 is a view as in Fig. 4, but at another

embodiment, Fig. 6 is a view as in Fig. 4, but in another

embodiment,

7 is a view in the circumferential direction of a blade in the region of

Shroud,

Fig. 8 is a view as in Fig. 2, but at another

embodiment,

9 is a sectional view of the blade of FIG. 8 in the region of

Shrouds corresponding to section lines IX in Fig. 8,

10 is a greatly simplified, basic cross-section through a

Turbomachine in the region of a row of blades,

11 is a view in the radial direction in the region of a blade according to an arrow Xl in Fig. 10,

12 shows a longitudinal section through the blade in the region of a

Shroud ring according to section lines XIV in Fig. 11,

13 is an axial view of the blade in the region of the shroud ring according to an arrow XIII in Fig. 11,

14 is a view in the circumferential direction of the blade in the region of

Shroud ring according to an arrow XIV in Figs. 10, 11 and 13. Ways to carry out the invention

According to FIG. 1, a turbomachine 1 is equipped with a rotor 2 and with a stator 3. The rotor 2 is rotatably mounted in the stator 3 in a conventional manner. The turbomachine 1 can basically be a compressor or a turbine. In the case of a turbine, it may be a steam turbine or gas turbine. The turbomachine 1 can be stationary and serve, for example, in a power plant for driving a generator. Likewise, the turbomachine 1 may be a drive unit in a vehicle, in particular in an aircraft. However, a realization of the invention in an embodiment of the turbomachine 1 as a stationary gas turbine is preferred.

The rotor 2 has, according to FIG. 1, at least one blade row 4, which consists of a plurality of rotor blades 5. 1 lies in the region of such a blade row 4, although only a single blade 5 is shown for illustration.

The turbomachine 1 is also equipped at least with a shroud 8. In the case of the embodiment shown in FIG. 1, the shroud 8 is assigned to the blade row 4 and is thereby attached to the outer ends of the rotor blades 5 remote from the rotor 2 arranged.

According to the invention, this shroud 8 is formed either by a shroud ring 32 or by a plurality of shroud segments 33 or by a plurality of cover plates 34. In this case, the shroud ring 32 is assigned to all blades 5 of the blade row 4 together. In contrast, that is respective shroud segment 33 simultaneously associated with a plurality of adjacent blades 5 of the blade row 4, while the respective cover plate 34 is associated with a respective blade 5 of the blade row 4. The shroud ring 32, the shroud segments 33 and the cover plates 34 have in common that they each form with respect to the blades 5 separate components which are secured to the blades 5 in a suitable manner. In Fig. 1, only a single shroud segment 33 is indicated in each case; Likewise, only a single cover plate 34 is indicated by way of example. Although the following description refers explicitly only to the shroud ring 32, it also implicitly applies correspondingly to the embodiments with shroud segments 33 or for the embodiments with cover plates 34.

The shroud ring 32 is preferably made in one piece, eg, by casting or forging. Likewise, an embodiment is possible in which the shroud ring 32 is assembled from a plurality of sections, in particular from a plurality of ring segments. The shroud ring 32 extends in the direction indicated by an arrow 9 circumferential direction closed, so without interruption. The shroud ring 32 is at least as self-supporting designed that it can be handled as a whole, which simplifies its assembly and disassembly. Furthermore, it can at least partially absorb the high centrifugal forces occurring during operation and remove them in the circumferential direction, which reduces the load on the associated rotor blades 5. The shroud ring 32 forms a separate component, which is manufactured independently of the rotor blades 5 and is mounted for mounting on the rotor blades 5. For this purpose, the shroud ring 32 and the blades 5 are fastened to each other by means of anchors 10. The shroud segments 33, which may be used to form the shroud 8, may also be secured to at least one of the associated moving blades 5 by means of such anchors 10. preferably attached to all associated blades 5. In a corresponding manner, in the event that the shroud 8 is formed from the cover plates 34, the individual cover plates 34 are fastened in each case by means of such anchors 10 to the respective associated blade 5. These anchors 10 are designed so that they act at least in the radial direction, ie in the radial direction tensile forces between the shroud ring 32 and the blades 5 can transmit. In addition, the anchors 10 are designed so that they are non-destructive solvable. In other words, the assembled shroud ring 32 can be dismantled without destroying the shroud ring 32 and without destroying the blades 5. This is for the later installation of a repaired or a new shroud ring 32 of significant cost advantage.

The anchors 10 can also be designed so that the shroud ring 32 is fixed in the assembled state with respect to the blades 5 in the circumferential direction 9 and / or in the axial direction, ie parallel to the axis of rotation 11 of the rotor. As a result, a defined position fixation for the shroud ring 32 is achieved relative to the associated blades 5. Preferred embodiments for the realization of the anchoring 10 will be explained in more detail below.

Preferably, the shroud ring 32 is secured with all the blades 5 of the associated blade row 4 via at least one such anchoring 10. Likewise, it is in principle possible for the shroud ring 32 to be fastened to at least one such anchoring 10 only on a few, preferably circumferentially symmetrically distributed, moving blades 5. The anchors 10 are each arranged radially between the shroud ring 32 and the respective blade 5. In principle, such anchoring 10 can be configured as desired, for example as a screw, as long as it is suitable for transmission of tensile force. A preferred embodiment of the anchor 10 will be explained in more detail below.

According to FIGS. 2 to 6, each anchoring 10 is equipped with at least one anchor receptacle 12 or 13 and with at least one armature 14 or 15 complementary to the respective armature receptacle 12, 13. 2 to 4, 6, 8 and 9 show a cover band side, that is formed in the shroud ring 32 anchor receptacle 12, while Figs. 5 and 6 show a blade-side, that is formed in the respective blade 5 anchor receptacle 13. The cooperating with the shroud side armature receptacle 12 anchor is denoted by 14, while the cooperating with the bucket side receptacle 13 anchor is denoted by 15. In the cover band-side anchor receptacle 12, the associated receiving profile 16 to the associated blade 5 is open. In contrast, in the blade-side armature receptacle 13, the receiving profile 16 to the shroud ring 32 is open. The anchor receptacles 12, 13 and their longitudinal directions extend exemplarily straight; Likewise, embodiments with curved longitudinal directions are possible. In the case of straight longitudinal directions, longitudinal edges of the anchor receptacles 12, 13 can run parallel to one another. Likewise, the longitudinal edges can be set or inclined to each other, whereby the anchor seats 12, 13 taper in the mounting direction. For curved longitudinal directions, the longitudinal edges may extend along concentric circular arcs. Likewise, longitudinal edge courses are possible along circular arcs with staggered circle centers, in which a conical constriction in the assembly direction results for the anchor receivers 12, 13 again. The anchor receivers 12, 13 are characterized by a constant in their longitudinal direction or conical receiving profile 16. This female profile 16 has at least one undercut 17 engageable radially behind. In the exemplary embodiments shown, the receiving profile 16 is a T-profile. Other suitable contours, for example a dovetail profile, can also serve as receiving profiles 16.

The respective armature 14, 15 has on its outer side an anchor profile 18, which is shaped complementary to the respective receiving profile 16. In the present case, therefore, the anchor profiles 18 are suitable T-profiles. In the assembled state, the respective armature 14, 15 is inserted into the associated armature receptacle 12, 13, in such a way that its armature profile 18 engages with the at least one undercut 17 of the receiving profile 16. In this way, an effective radial connection between the shroud ring 32 and the respective blade 5 is realized, which is suitable for transmitting very large forces.

In the embodiment shown in FIGS. 2 to 4 and 8, 9, the armature 14 is designed as an integral part of the respective blade 5. This armature 14 is thus from the unspecified blade head of the respective blade 5 in the radial direction. In contrast, Fig. 5 shows an alternative embodiment in which the armature 15 forms an integral part of the shroud ring 32 and thus radially protrudes from this on one of the blade 5 facing side.

6 shows another advantageous embodiment, in which the anchoring 10 has an additional component, namely an anchor body 31, which constitutes a separate component with respect to the shroud ring 32 and with respect to the respective moving blade 5. This anchor body 31 is provided with two anchors 14, 15 provided or configured so that it has the two anchors 14, 15. Accordingly, the anchoring 10 in this embodiment comprises both the shroud-side armature receptacle 12 and the shovel-side armature receptacle 13. The two armature receivers 12, 13 are arranged so that they are radially opposite each other and in particular radially aligned with each other. Preferably, the two armature receivers 12, 13 formed congruent to each other and arranged. The anchor body 31 here has a double-T-profile or an H-profile. The anchor body 31 is now in the assembled state via its two armatures 14, 15 with two anchor seats 12, 13 in engagement. This embodiment may be advantageous in terms of assembly and disassembly, as it facilitates, for example, the positioning of the shroud ring 32 on the blades 5.

In the embodiments of FIGS. 2 to 6, the respective armature receptacle 12, 13 are each arranged such that their longitudinal direction extends axially, ie parallel to the axis of rotation 11. With such an orientation of the anchor receptacles 12, 13, the anchorage 10 has a relatively small length in the longitudinal direction of the anchor receptacle 12, 13. In the axial orientation of the armature receptacle 12, 13, the anchor 10 can additionally transfer peripheral forces between the shroud ring 32 and the respective blades 5. The assembly of the shroud ring 32 on the rotor blades 5 takes place in such a way that the respective armature 14, 15 is inserted into the associated armature receptacle 12, 13 in its longitudinal direction. The longitudinal direction of the armature receptacle 12, 13 thus corresponds to the mounting direction of the anchor 10. For mounting the anchor 10 thus the receiving profile 17 in the longitudinal direction of the associated anchor receptacle 12, 13 at least unilaterally open.

In the embodiment shown in FIGS. 8 and 9, the anchoring 10 is designed such that the armature receptacle 12 with respect to the axial direction, represented by an arrow 19, has a slope. Accordingly, the longitudinal direction of the armature receptacle 12 extends inclined with respect to the axial direction 19. An inclination angle is denoted by 20. Due to the inclined orientation of the anchor receptacle 12, the anchor 10 can also transmit axial forces between the shroud ring 32 and the respective blade 5.

For the transmission of axial forces, the anchor seats 12, 13 may be configured conically in the mounting direction. Additionally or alternatively, the anchor receptacle 12 may be provided according to FIG. 3 with an axial stop 21 which limits the longitudinal adjustability of the armature 14 in the armature receptacle 12. The receiving profile 17 of the anchor receptacle 12 is therefore in this embodiment in the longitudinal direction of the anchor receptacle 12 on one side, e.g. on the upstream side, closed. In principle, the receiving profile 17 of the respective anchor receptacle 12, 13 in the longitudinal direction of the anchor receptacle 12, 13 be open on both sides.

8 shows a special embodiment in which the longitudinal direction of the armature receptacle 12 inclines approximately in the same way as the blade profile 22. The angle of inclination 20 is approximately in the range of an unspecified angle of attack of the blade profile 22, between the by an arrow 23 indicated flow direction and by a leading edge 24 and a trailing edge 25 extending longitudinal direction of the blade profile 22 is clamped. In this embodiment results for the anchorage 10 in its mounting direction, ie parallel to the longitudinal direction of the anchor receptacle 12 a particularly long length, which may be advantageous for the assembly. At the same time, the anchoring 10 can thereby be largely integrated into the outer contour of the respective blade 5. Your bucket head must therefore only comparatively slightly by a thickened cross-section be enlarged. The region with a thickened cross-section is indicated in FIG. 3 by a curly bracket and denoted by 26. The anchoring 10 thus builds comparatively slim.

The relatively large length of the anchor 10 in the longitudinal direction of the blade profile 22 according to the embodiment of FIG. 8 causes as well as the relatively large width of the anchor 10 parallel to the longitudinal direction of the blade profile 22 according to the other embodiments in a twisting of the respective blade 5 in the operation of Turbomachine tilting of the armature 14, 15 in the respective armature receptacle 12, 13. This tilting in turn leads to a frictional connection, which enhances the holding force between the shroud ring 32 and the respective blade 5.

In an advantageous development, it can be provided to fix the respective armature 14, 15 in the associated armature receptacle 12, 13 by means of a shrink fit, which leads to a prestressed, frictional coupling between the cover band ring 32 and the respective blade 5.

The respective anchoring 10 can be configured as a sliding seat by a corresponding adjustment of the armature receptacle 12, 13 and the armature 14, 15, which facilitates a mounting parallel to the longitudinal direction of the armature receptacle 12, 13. It may be expedient to equip the respective anchoring 10 with a securing device 35. This securing device 35 is configured such that in the assembled state of the shroud ring 32 within the respective anchoring 10, the relative position between anchor receptacle 12, 13 and anchor 14, 15 fixed. For example, the securing device 35 may be formed by a pin-shaped securing element 36, which is transverse to the longitudinal direction of the armature receptacle 12, 13, preferably extends radially. This fuse element 36 penetrates in the embodiments of FIGS. 4 and 5 each one hand in a unspecified, formed in the shroud ring 32 first opening and on the other hand simultaneously formed in the respective blade 5, unspecified second opening a positive fit. In the embodiment according to FIG. 6, the securing element 36 additionally penetrates the anchor member 31 in a passage opening formed therein, which is not described in more detail.

As can be seen in FIGS. 4 to 6, the shroud ring 32 may, in specific embodiments, comprise cooling channel structures 27, which are indicated here only schematically with broken lines. These cooling channel structures 27 are used to cool the shroud ring 32 and can, for example, form a coolant path remaining in the interior of the shroud ring 32 and / or have exit openings 28 ending at the surface of the shroud ring 32, through the cooling means, also for forming a cooling film on the surface of the shroud ring 32 can escape. In the assembled state, the cooling channel structures 27 of the shroud ring 32 communicate with cooling channel structures 29, which are formed in the interior of the respective rotor blade 5. In this way, the cooling channel structures 27 of the shroud ring 32 are supplied via the cooling channel structures 29 of the respective blade 5 with coolant. In this case, the independent of the blades 5, separate construction of the shroud ring 32 of the formation of complex cooling channel structures 27 in the shroud ring 32 benefit because they can be produced before mounting on the blades 5 in the shroud ring 32.

It is clear that in the contact area between the shroud ring 32 and the respective blades 5 suitable, not shown here sealing means may be provided to the shroud side Cooling channel structures 27 fluidly sealed to the outside to connect the blade-side cooling channel structures 29.

According to FIG. 7, the shroud ring 32 may be equipped with a sealing structure 30 in a further development of the invention. This is arranged on a side facing away from the blades 5 side of the shroud ring 32. The sealing structure 30 is also indicated here only by a broken line and exemplarily has the form of a radially projecting and circumferentially closed 9 web, so-called fin. The seal structure 30 then cooperates with a radially adjacent wall of either the rotor 2 or the stator 3 to form an axial seal of the respective blade row 4. For example, the web indicated in FIG. 7 dips into a corresponding annular groove, thereby producing the effect of a labyrinth seal. For the design of such sealing structures 30, there are many models in the prior art, so that it need not be discussed in more detail here. Other sealing structures 30 are, for example, an abrasive structure which interacts with a grindable counter-structure, one of these structures forming the sealing structure 30 of the shroud ring 32, while the other structure is then formed on the rotor 2 or on the stator 3.

According to the figures 10 to 14 a possible embodiment of the shroud 8 is described as shroud ring 108.

According to FIG. 10, a turbomachine 101 is equipped with a rotor 102 and with a stator 103. The rotor 102 is rotatably mounted in the stator 103 in a conventional manner. The turbomachine 101 may basically be a compressor or a turbine. The turbomachine 101 may be stationary and, for example, in one Power plant for driving a generator serve. Likewise, the turbomachine 101 may basically be a drive unit in a vehicle, in particular in an aircraft. However, a realization of the invention in an embodiment of the turbomachine 101 as a stationary gas turbine is preferred.

According to FIG. 10, the rotor 102 has at least one row of blades 104, which consists of a plurality of rotor blades 105. The cross section according to FIG. 10 lies in the region of such a blade row 104, although only a single blade 105 is shown for the purpose of illustration.

According to the invention, the turbomachine 101 can now be equipped at least with a shroud ring 108. This shroud ring 108 is assigned to one of the blade rows 104, and that common to all blades 105 of the respective blade row 104. In the embodiment shown in Fig. 10, the shroud ring 108 of the blade row 104 is assigned and is thereby at the remote from the rotor 102 outer ends the blades 105 arranged.

The shroud ring 108 is preferably made in one piece, e.g. by casting or forging. Likewise, an embodiment is possible in which the shroud ring 108 is assembled from a plurality of sections, in particular from a plurality of ring segments.

The shroud ring 108 is a separately manufactured component with respect to the blades 105. In this way, an optimization of the shroud ring 108 can be realized in terms of strength by appropriate choice of material and aerodynamics by appropriate shaping. The shroud ring 108 extends closed in the direction indicated by an arrow 109 circumferential direction, ie without interruption. The shroud ring 108 is self-supporting, whereby it can absorb the forces occurring during operation in itself. This property is of particular interest in the variant according to FIG. 10, since high centrifugal forces occur there during operation due to the rotation of the rotor 102. In addition, the shroud ring 108 forms a separate component, which is made independently of the blades 105 and is mounted for mounting on the blades 105. For this purpose, the shroud ring 108 and the rotor blades 105 are coupled together in coupling regions 1010.

These coupling regions 1010 can be designed so that the shroud ring 108 is radially free in the assembled state with respect to the blades 105. In the embodiment according to FIG. 10, the shroud ring 108 can thus increase its diameter due to the effective centrifugal forces and due to thermal expansion, without thereby inducing tensile forces in the rotor blades 105. In addition, the coupling regions 1010 can also be designed so that the shroud ring 108 is fixed in the mounted state with respect to the rotor blades 105 in the axial direction, ie parallel to the axis of rotation 1011 of the rotor 102 and additionally or alternatively in the circumferential direction 109. As a result, a defined position fixation for the shroud ring 108 is achieved relative to the associated blades 105. A preferred embodiment for realizing the radial freedom and the axial and tangential fixing of the shroud ring 108 relative to the rotor blades 105 is explained in more detail below with reference to FIGS. 11 and 12.

Referring to FIGS. 11 and 12, the shroud ring 108 may be secured to at least one of its associated blades 105 by means of a securing device 1012. Basically, the Shroud ring 108 may be attached to each blade 105 with at least one such securing device 1012. In FIGS. 11 and 12, two different variants of the securing device 1012 or 1012 'are shown, which can be realized cumulatively or alternatively. The respective securing device 1012, 1012 'is characterized in that it secures the shroud ring 108 on the respective moving blade 105 in the axial direction and / or in the circumferential direction 109 against relative adjustments, thus realizing the above-mentioned fixing. The respective securing device 1012, 1012 'is formed radially between the shroud ring 108 and the respective blade 105.

For this purpose, the securing device 1012, 1012 'in the preferred embodiment shown here is equipped with at least one securing member 1013 or 1013'. The securing member 1013, 1013 'is arranged radially movable on the respective moving blade 105. For example, it is for this purpose in a correspondingly shaped guide opening 1014 and 1014 'guided in the radial direction adjustably mounted.

The two safety devices 1012, 1012 ', which are shown here by way of example, differ, for. B. by the shape of their securing members 1013, 1013 '. While one securing member 1013 is configured as a cylindrical bolt, the other securing member 1013 'has the shape of a rectilinear web which extends between an unspecified leading edge of the blade profile and an unspecified trailing edge of the blade profile.

The respective securing device 1012, 1012 'comprises for each securing member 1013, 1013' an associated securing opening 1015 or 1015 ', which is formed on the cover band ring 108 and aligned with the Guide opening 1014, 1014 'is arranged. The respective securing opening 1015, 1015 'is so matched to the associated securing member 1013, 1013' that the securing member 1013, 1013 'in the radial direction in the associated securing opening 1015, 1015' can penetrate. As soon as the securing member 1013, 13 'protrudes so far from its guide opening 1014, 1014' that it projects into the securing opening 1015, 1015 ', the desired fixing or securing is present in the axial direction and in the circumferential direction. The guide openings 1014, 1014 'are just like the securing openings 1015, 1015' complementary to the respective securing member 1013, 1013 'shaped.

Since the respective securing member 1013, 1013 'is radially movably mounted both in the associated guide opening 1014, 1014' and in the associated securing opening 1015, 1015 ', the radial degree of freedom for the covering band ring 108 at the same time is ensured relative to the moving blade 105.

The penetration of the securing member 1013, 1013 'in the securing opening 1015, 1015' takes place at the blade ring 104 associated shroud 108 during operation of the turbomachine 101 by the prevailing centrifugal forces, since these the securing member 1013, 1013 'radially outward, ie in the respective Drive fuse opening 1015, 1015 'into it. The dimensioning of the respective securing opening 1015, 1015 'is expediently chosen so that the securing member 1013, 1013' is still partially disposed in the guide opening 1014, 1014 'upon reaching a radial stop not designated in detail.

In order to be able to guarantee the desired securing effect or fixing effect at standstill of the turbomachine 101 as well, For example, the securing member 1013, 1013 'can be radially biased in the direction of the securing opening 1015, 1015' by means of a securing spring 1016 or 1016 '. The radially biased securing member 1013, 1013 'also ensures during assembly of the shroud ring 108 an audible snap when reaching the predetermined relative position between the shroud ring 108 and the associated blade 105th

To accommodate the respective securing device 1012, 1012 ', the associated moving blade 105 may be thickened in the region of its blade head transversely to its blade profile. This thickened head zone is indicated by a curly bracket in FIG. 12 and denoted by 1017.

According to a preferred embodiment, the assembly of the shroud ring 108 expediently so that the once mounted shroud ring 108 can be removed again without destruction of the blades 105 as needed. This non-destructive loosening of the blades 105 can be particularly easily realized in the embodiment shown here, which works for securing or fixing with the securing device 1012, 1012 '. For example, the shroud ring 108 for each securing member 1013, 1013 'at least one unlocking opening 1018 and 1018'. This unlocking 1018, 1018 'is positioned so that through them the respective securing member 1013, 1013' using a suitable, in the unlocking 1018, 1018 'insertable tool, from the securing opening 1015, 1015' can be driven out. The respective securing member 1013, 1013 'can thus be displaced into the guide opening 1014, 1014' against the securing spring 1016, 1016 'until the shroud ring 108 is released from the respective moving blade 105.

According to FIG. 13, in a particular embodiment, the shroud ring 108 may include cooling channel structures 1019, which are only schematically illustrated here are indicated by broken lines. These cooling channel structures 1019 serve to cool the shroud ring 108 and may, for example, form a coolant path remaining in the interior of the shroud ring 108 and / or comprise exit openings 1020 ending at the surface of the shroud ring 108, through which coolant also forms a cooling film on the surface of the shroud ring 108 can escape. When mounted, the cooling channel structures 1019 of the shroud ring 108 communicate with cooling channel structures 1021 formed inside the respective blade 105. In this way, the cooling channel structures 1019 of the shroud ring 108 are supplied with coolant via the cooling channel structures 1021 of the respective rotor blade 105. The separate construction of the shroud ring 108, which is independent of the blades 105, is beneficial for the formation of complex cooling channel structures 1019 in the shroud ring 108, since these can be produced in the shroud ring 108 prior to assembly on the rotor blades 105. It is clear that suitable sealing means may be provided for the fluidic coupling of the shroud side cooling channel structures 1019 with the shovel side cooling channel structures 1021.

According to FIG. 14, the shroud ring 108 may be equipped with a sealing structure 1022 in a further development of the invention. This is arranged on a side facing away from the blades 105 side of the shroud ring 108. The sealing structure 1022 is also indicated here only by a broken line and has, for example, the shape of a radially projecting and circumferentially closed circumferential ridge, so-called fin. The seal structure 1022 then cooperates with a radially adjacent wall of either the rotor 102 or the stator 103 to form an axial seal of the respective blade row 104. For example, the ridge indicated in FIG. 14 dips into a corresponding annular groove to thereby produce the effect of a labyrinth seal. For the design of such sealing structures 1022, there are many models in the art, so that it need not be discussed in more detail here. Other sealing structures 1022 are, for example, an abrasive structure which cooperates with a grindable structure, one of these structures forming the sealing structure 1022 of the shroud ring 108, while the other structure is then formed on the rotor 102 or on the stator 103.

LIST OF REFERENCE NUMBERS

turbomachine

rotor

stator

Blade row

blade

vane row

vane

shroud

circumferentially

anchoring

axis of rotation

anchor recording

anchor

Up Silhouette

undercut

anchor contour

axially

tilt angle

attack

blade profile

flow direction 24 leading edge

25 outflow edge

26 thickened area of 5, 7

27 cooling channel structure

28 outlet opening

29 cooling channel structure

30 sealing structure

31 anchor body

32 shroud ring

33 shroud segment

34 cover plate

35 safety device

36 fuse element

101 turbomachine

102 rotor

103 stator

104 blade row

105 blade

106 vane row

107 vane

108 shroud ring

109 circumferential direction

1010 coupling area

1011 rotation axis

1012, 1012 ^' securing device

1013, 1013 ^' securing member

1014, 1014 ^' guide opening

1015, 1015 ^' securing opening 1016, 1016 ^' retaining spring

1017 thickened area of 105, 107

1018, 1018 ^' release opening

1019 cooling channel structure in 108

1020 Coolant outlet opening

1021 cooling channel structure in 105, 107

1022 sealing structure

Claims

claims

1. Turbomachine (1,101), in particular turbine or compressor,

with a rotor (2, 102) having at least one blade row (4, 104) with a plurality of blades (5, 105),

with a stator (3, 103) having at least one row of guide vanes (6, 106) with a plurality of guide vanes (7, 107),

- Wherein at least for one blade row (4, 104) all shovels tips (5, 105) of the blade row (4, 104) associated shroud (8, 108) is provided, characterized in that the shroud (8, 108) formed so self-supporting is that it can at least partially absorb the centrifugal forces occurring during operation and remove them in the circumferential direction.

2. Turbomachine according to claim 1, characterized

- That the shroud (8) by a all blades (5) of the blade row (4) common in the circumferential direction (9) closed shroud ring (32) is formed on each of several or all blades (5) of the blade row (4) at least one at least radially effective, non-destructively releasable anchoring (10) is attached, or

- that the shroud (8) by several, in each case a plurality of blades (5) of the blade row (4) commonly associated shroud segments (33) is formed, which is attached to at least one of the associated blades (5) via at least one at least radially effective, non-destructively releasable anchoring (10), or

in that the shroud (8) is formed by a plurality of cover plates (34), each associated with a blade (5) of the blade row (4), each of which is connected to the associated blade (5) via at least one at least radially effective, non-destructively releasable anchoring (10 ) is attached.

3. turbomachine according to claim 2, d a d e c e c e n e c e n e,

- That the anchoring (10) at least one in the shroud ring (32) or in the shroud segment (33) or in the cover plate (34) formed shroud-side anchor receptacle (12) which is open to the respective blade (5) and one in its longitudinal direction having constant receiving profile (16) with at least one undercut (17) which can be gripped behind radially,

in that the anchoring (10) has at least one anchor (14) with an anchor profile (18) designed to be complementary to the receiving profile (16), which is inserted into the anchor receptacle (12) and has its anchor profile (18) with the at least one undercut ( 17) is engaged.

4. Turbomachine according to one of claims 1 to 3, d a d e c e c e n e c e n e,

- That the anchoring (10) at least one formed in the respective blade (5) shovel-side anchor receptacle (13) which is open to the shroud (8) and a constant in its longitudinal direction or conical receiving profile (16) with at least one radially engageable behind Having undercut (17),

- that the anchoring (10) has at least one anchor (15) with an anchor profile (18) designed to be complementary to the receiving profile (16). has, which is inserted into the anchor receptacle (13) and via its armature profile (18) with the at least one undercut (17) is engaged.

5. Turbomachine according to claim 3 or 4, characterized

- That the cooperating with the cover band-side armature receptacle (12) armature (14) is an integral part of the respective La ufLauf schaufei (5) and protrudes radially from the blade head, and / or

- That with the blade-side armature receptacle (13) cooperating armature (15) is an integral part of the shroud ring (32) or the shroud segment (33) or the cover plate (34) and projects radially therefrom.

6. Turbomachine according to claims 3 and 4, characterized

- that the anchoring (10) both at least one shroud-side armature receptacle (12) and at least one blade-side anchor receptacle (13) which are arranged radially opposite each other,

in that the anchorage (10) has at least one anchor body (31) which is in relation to the shroud ring (32) and the rotor blades (5) or to the shroud segment (33) and the rotor blades (5) or to the cover plate (34) and the Blades (5) is a separate component and on the one hand cooperating with the cover band-side armature receptacle (12) anchor (14) and on the other hand with the blade-side armature receptacle (13) cooperating armature (15).

7. Turbomachine according to one of claims 3 to 6, characterized

- That the respective anchor receptacle (12, 13) is arranged so that its longitudinal direction extends axially, or - That the respective anchor receptacle (12, 13) is arranged so that its longitudinal direction relative to the axial direction extends inclined, or

- That the respective anchor receptacle (12, 13) is arranged so that its longitudinal direction extends substantially parallel to the longitudinal direction of the blade profile (22).

8. Turbomachine according to one of claims 3 to 7, characterized

- That the receiving profile (16) of the respective anchor receptacle (12, 13) is closed on one side in its longitudinal direction and / or is open only on the downstream side, and / or

- That the anchoring (10) with a securing device (35) for fixing the relative position between the armature receptacle (12, 13) and armature (14, 15) is equipped.

9. turbomachine according to one of claims 2 to 8, characterized in that the shroud ring (32) or the shroud segment (33) or the cover plate (34) cooling channel structures (27) for cooling the shroud ring (32) or the shroud segment (33) or the cover plate (34) during operation of the turbomachine (1), which are in the assembled state of the shroud ring (32) or the shroud segment (33) or the cover plate (34) with cooling channel structures (29) of the blades (5) communicatively connected.

10. Turbomachine according to one of claims 2 to 9, characterized in that the shroud ring (32) or the shroud segment (33) or the cover plate (34) on one of the blades (5) facing away from a sealing structure (30) to the axial seal of the blade row (4) during operation of the turbomachine (1).

11. Turbomachine according to claim 1, characterized in that at least for one blade row (104) one for all blades (105) of the blade row (104) common, in the circumferential direction (109) closed, self-supporting shroud ring (108) is provided, which to the Blades (105) of the blade row (104) is mounted.

12. Turbomachine according to claim 11, characterized in that the shroud ring (108) on the moving blades (105) is mounted so that it with respect to the blades (105) is radially free.

13. Turbomachine according to claim 11 or 12, characterized in that the shroud ring (108) on the moving blades (105) is mounted so that it is fixed relative to the blades (105) axially and / or in the circumferential direction.

14. Turbomachine according to one of claims 11 to 13, characterized in that the shroud ring (108) is attached to the blades (105) non-destructively releasably attached.

15. Turbomachine according to one of claims 11 to 14, characterized the shroud ring (108) is secured against relative displacement at least on a moving blade (105) with a securing device (1012) axially and / or in the circumferential direction (109).

16. Turbomachine according to claim 15, characterized in that

- That the respective securing means (1012) at least one securing member (1013) which is arranged radially movable on the respective blade (105) and at least during operation of the turbomachine in a formed on the shroud ring (108) securing opening (1015) radially penetrates, and or

- That the securing member (1013) by means of a securing spring (1016) is biased to penetrate into the securing opening (1015), and / or

- That the securing member (1013) is configured as a cylindrical bolt or as extending between the leading edge and the trailing edge of the blade profile web, and / or

- That the shroud ring (108) for each securing member (1013) includes at least one Entsicherungsöffnung (1018) through which the securing member (1013) by means of a suitable tool from the securing opening (1015) out into the associated blade (105) is drivable.

17. Turbomachine according to one of claims 11 to 16, characterized in that the shroud ring (108) is made of one piece or assembled from several individual parts.

18. Turbomachine according to one of claims 11 to 17, characterized in that the shroud ring (108) contains cooling channel structures (1019) for cooling the shroud ring (108) during operation of the turbomachine (101), which in the assembled state of the shroud ring (108) are communicatively connected to cooling channel structures (1021) of the rotor blades (105).

19. Turbomachine according to one of claims 11 to 18, characterized in that the shroud ring (108) on its side remote from the blades (105) side has a sealing structure (1022) to the axial seal of the blade row (104) during operation of the turbomachine (101) ,

20 shroud ring for mounting on blades (5, 105) of a blade row (4, 104) of a turbomachine (1, 101), in particular turbine or compressor, with a rotor (2, 102), the at least one blade row (4, 104 ) comprising a plurality of rotor blades (5, 105) and a stator (3, 103) which has at least one row of guide vanes (6, 106) comprising a plurality of stator blades (7, 107), the shroud ring (8, 108 ) in the circumferential direction (9, 109) closed and designed self-supporting and for all blades (5, 105) of the blade row (4, 104) is provided together.

21. shroud ring according to claim 20, characterized by the characterizing features of at least one of claims 11 to 19.

22 shroud for mounting on blades (5) of a blade row (4) of a turbomachine (1), in particular turbine or compressor, with at least one blade row (4) with a plurality of blades (5) and with at least one row of guide vanes (6) is equipped with a plurality of guide vanes (7),

- wherein the shroud (8) by a all blades (5) of the blade row (4) commonly associated in the circumferential direction (9) closed shroud ring (32) is formed on several or on all blades (5) of the blade row (4) in each case via at least one at least radially effective, non-destructively releasable anchoring (10) is attached, or

- Wherein the shroud (8) by several, each more blades (5) of the blade row (4) jointly associated shroud segments (33) is formed on each at least one of the associated blades (5) via at least one at least radially effective, non-destructively releasable Anchoring (10) is attached, or

- wherein the shroud (8) by a plurality of each blade (5) of the blade row (4) associated cover plates (34) is formed on each of the associated blade (5) via at least one at least radially effective, non-destructively releasable anchoring (10 ) is attached.

23. The shroud according to claim 22, wherein the characterizing features of at least one of claims 1 to 10 are present.