U.S. patent application number 12/045895 was filed with the patent office on 2008-12-04 for turbo machine.
Invention is credited to Joergen Ferber, James Ritchie, Slawomir Slowik.
Application Number | 20080298970 12/045895 |
Document ID | / |
Family ID | 37429292 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080298970 |
Kind Code |
A1 |
Ferber; Joergen ; et
al. |
December 4, 2008 |
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.
Inventors: |
Ferber; Joergen;
(Wutocschingen, DE) ; Ritchie; James; (Ennetbaden,
CH) ; Slowik; Slawomir; (Stetten, CH) |
Correspondence
Address: |
CERMAK KENEALY & VAIDYA LLP
515 E. BRADDOCK RD, SUITE B
ALEXANDRIA
VA
22314
US
|
Family ID: |
37429292 |
Appl. No.: |
12/045895 |
Filed: |
March 11, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2006/065879 |
Aug 31, 2006 |
|
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|
12045895 |
|
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Current U.S.
Class: |
416/189 |
Current CPC
Class: |
Y02T 50/60 20130101;
F05B 2240/33 20130101; Y02T 50/673 20130101; F01D 5/225 20130101;
F05D 2230/60 20130101; F05D 2260/30 20130101; Y02T 50/671
20130101 |
Class at
Publication: |
416/189 |
International
Class: |
F01D 5/22 20060101
F01D005/22 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 15, 2005 |
CH |
01508/05 |
Sep 15, 2005 |
CH |
01509/05 |
Claims
1. A turbo machine comprising: a rotor having at least one moving
blade row with a plurality of moving blades; a stator having at
least one guide vane row with a plurality of guide vanes; a shroud
assigned to all the moving blade tips of at least one moving blade
row; wherein the shroud is configured and arranged to be
self-supporting so that it can at least partially absorb the
centrifugal forces arising during operation of the turbo machine
and discharge them in the circumferential direction; wherein the
shroud comprises a shroud ring assigned jointly to all the moving
blades of said at least one moving blade row and is
circumferentially closed; and wherein the shroud ring is fastened
to at least a plurality of the moving blades of said at least one
moving blade row each via at least one, at least radially active,
non-destructively releasable, anchoring.
2. The turbo machine as claimed in claim 1, wherein: the at least
one anchoring has at least one shroud-side anchor receptacle formed
in the shroud ring and which is open toward the respective moving
blade and has a reception profile, constant in the longitudinal
direction of said anchor receptacle, with at least one undercut
accessible radially; and the at least one anchoring has at least
one anchor with an anchor profile configured complementarily to the
reception profile, which at least one anchor is positioned in the
anchor receptacle and is in engagement via its anchor profile with
the at least one undercut.
3. The turbo machine as claimed in claim 1, wherein: the at least
one anchoring has at least one blade-side anchor receptacle formed
in the respective moving blade and which is open toward the shroud
and has a reception profile, constant or conical in the
longitudinal direction of said anchor receptacle, with at least one
undercut accessible radially; and the at least one anchoring has at
least one anchor with an anchor profile configured complementarily
to the reception profile, which at least one anchor is positioned
in the anchor receptacle and is in engagement via its anchor
profile with the at least one undercut.
4. The turbo machine as claimed in claim 2, wherein: the at least
one anchor cooperating with the shroud-side anchor receptacle is an
integral part of the respective moving blade and projects radially
from its moving blade head; or the at least one anchor cooperating
with the blade-side anchor receptacle is an integral part of the
shroud ring and projects radially from the shroud ring; or
both.
5. The turbo machine as claimed in claim 3, wherein: the at least
one anchoring has both at least one shroud-side anchor receptacle
and at least one blade-side anchor receptacle arranged radially
opposite one another; and the at least one anchoring has at least
one anchor body which is a separate component from the shroud ring
and from the moving blades, the at least one anchor body including
the at least one anchor cooperating with the shroud-side anchor
receptacle and the at least one anchor cooperating with the
blade-side anchor receptacle.
6. The turbo machine as claimed in claim 2, wherein: the at least
one anchor receptacle is arranged such that its longitudinal
direction extends axially; or the at least one anchor receptacle is
arranged such that its longitudinal direction extends at an
inclination with respect to the axial direction; or the at least
one anchor receptacle is arranged such that its longitudinal
direction extends essentially parallel to the longitudinal
direction of the moving blade profile.
7. The turbo machine as claimed in claim 2, wherein: the reception
profile of the at least one anchor receptacle is closed on one side
in its longitudinal direction, or is open only on the outflow side,
or both; or the at least one anchoring comprises a securing device
configured and arranged to fix the relative position between the at
least one anchor receptacle and the at least one anchor; or
both.
8. The turbo machine as claimed in claim 1, wherein: the shroud
ring contains cooling duct structures configured and arranged to
cool the shroud ring when the turbo machine is in operation; the
moving blades comprise cooling duct structures configured and
arranged to cool the moving blades when the turbo machine is in
operation; and the shroud ring cooling duct structures are in fluid
communication with the moving blade cooling duct structures.
9. The turbo machine as claimed in claim 1, wherein the shroud ring
comprises, on a side facing away from the moving blades, a sealing
structure configured and arranged to axially seal the gap between
the shroud ot the at least one moving blade row) and the stator
when the turbo machine is in operation.
10. A shroud to be mounted on moving blades of a moving blade row
of a turbo machine, the turbo machine being equipped with at least
one moving blade row having a plurality of moving blades and with
at least one guide vane row having a plurality of guide vanes, the
shroud comprising: a shroud ring assigned jointly to all the moving
blades of the moving blade row and circumferentially closed, the
shroud ring being configured and arranged to be fastened to at
least a plurality of the moving blades of the moving blade row each
via at least one at least radially active, non-destructively
releasable, anchoring.
11. The turbo machine as claimed in claim 3, wherein: the at least
one anchor receptacle is arranged such that its longitudinal
direction extends axially; or the at least one anchor receptacle is
arranged such that its longitudinal direction extends at an
inclination with respect to the axial direction; or the at least
one anchor receptacle is arranged such that its longitudinal
direction extends essentially parallel to the longitudinal
direction of the moving blade profile.
12. The turbo machine as claimed in claim 3, wherein: the reception
profile of the at least one anchor receptacle is closed on one side
in its longitudinal direction, is open only on the outflow side, or
both; or the at least one anchoring comprises a securing device
configured and arranged to fix the relative position between the at
least one anchor receptacle and the at least one anchor; or both.
Description
[0001] This application is a Continuation of, and claims priority
under 35 U.S.C. .sctn. 120 to, International application no.
PCT/EP2006/065879, filed 31 Aug. 2006, and claims priority
therethrough under 35 U.S.C. .sctn..sctn. 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,
the stator usually has a plurality of guide vane rows which
include, in each case, a plurality of guide vanes.
[0006] In this context, it is basically known to provide the moving
blade rows and/or the guide vane rows with a shroud which, in the
mounted state, possesses an annular arrangement and connects the
free blade or vane ends of adjacent blades or vanes to one another
within the same blade or vane row. With the aid of shrouds of this
type, the aerodynamics of the respective blade or vane row can be
improved, thus increasing the efficiency of the turbo machine
equipped with them. 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.
[0007] GB 1 509 185 A discloses a moving blade row, in which the
individual moving blades are connected to one another in the region
of their blade tips via shroud segments arranged between them.
[0008] 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.
SUMMARY
[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.
[0011] According to an advantageous embodiment, the anchoring may
have at least one anchor receptacle which has a reception profile
which is constant in a longitudinal direction of the anchor
receptacle and is open radially on one side and has at least one
undercut accessible radially to engagement. Furthermore, the
anchoring may have at least one anchor with an anchor profile
configured complementarily to the reception profile and which can
be inserted into the anchor receptacle, so that its anchor profile
is in engagement with the at least one undercut of the anchor
receptacle. Thus, by the anchoring, a positive and particularly
load-bearing mechanical connection is made between the respective
moving blade and the shroud ring or the respective shroud segment
or the respective shroud plate.
[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.
[0013] The use of anchors and anchor receptacles of this type leads
additionally, besides the radial securing of the shroud to the
moving blades, to a fixing of the shroud transversely to the
longitudinal direction of the anchor receptacles. Thus, in the case
of an axially oriented anchor receptacle, fixing occurs in the
circumferential direction. Insofar as the anchor receptacle is
inclined with respect to the axial direction, moreover, this
results in holding forces in the axial direction.
[0014] A further advantage is seen in that, in the case of a
distortion of the moving blades, at least elongate anchors lead
additionally to a nonpositive securing of the shroud to the moving
blades. 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.
[0015] Another aspect of the invention includes, according to an
alternative embodiment, not forming the respective shroud from a
plurality of shroud plates or shroud portions assigned to
individual moving blades, but, instead, forming it from a single
shroud ring which is assigned to all the moving blades of the
respective moving blade row and which has a self-supporting
configuration and is built onto the radially outer moving blade
tips of the moving blade row. The self-supporting shroud ring is
configured such that, particularly when it is assigned to a moving
blade row, it can absorb in itself the forces arising during
operation, without at the same time subjecting the moving blades to
load. In particular, the centrifugal forces arising during
operation can be absorbed, without a significant additional radial
tensile load on the moving blades occurring at the same time. The
useful life of the moving blades is thereby increased. Likewise,
the moving blades may have a weaker dimensioning, which is useful
for a weight reduction which increases the efficiency of the turbo
machine. This is achieved by the shroud ring body, which is closed
in the circumferential direction and which converts the centrifugal
forces arising into tangential tensile stresses. So that the shroud
ring can be built onto the moving blade, the shroud ring must be a
component produced separately with respect to the moving blades.
The separate production of the shroud ring makes it possible to use
a material which differs from that of the moving blades and/or a
material structure which differs from that of the moving blades.
For example, the shroud ring may be optimized in the direction of
tensile load in the circumferential direction, whereas the moving
blades are usually optimized in terms of tensile load in the radial
direction.
[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.
[0018] In a preferred embodiment, the shroud ring may be built onto
the moving blades such that it is radially free with respect to the
moving blades. That is to say, the shroud ring is not fixed to the
moving blades in the radial direction, but, instead, is arranged
freely movable, or loosely in relation to the moving blades. Thus,
for example, thermally induced stresses can be reduced. This type
of construction is particularly advantageous when the shroud ring
is used in a moving blade row. The centrifugal forces arising
during operation force the shroud ring radially outward. Owing to
the degree of freedom provided in the radial direction, the shroud
ring can basically lift off from the associated moving blades in
the radial direction, without tensile forces in this case being
transmitted between the shroud ring and the moving blades. In terms
of the centrifugal forces, therefore, the moving blades are
decoupled from the shroud ring.
[0019] In this case, depending on the configuration of the coupling
between the shroud ring and the moving blades, even a coupling of
the moving blades in a circumferential direction to avoid the
excitation of oscillations can nevertheless be ensured.
[0020] Further important features and advantages of the turbo
machine according to the invention may be gathered from the
drawings and from the accompanying figure description with
reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Preferred exemplary embodiments of the invention are
illustrated in the drawings and are explained in more detail in the
following description, the same reference symbols referring to
identical or similar or functionally identical components. In the
drawings, in each case diagrammatically,
[0022] FIG. 1 shows a greatly simplified basic cross section
through a turbo machine in the region of a moving blade row,
[0023] FIG. 2 shows a view in the radial direction in the region of
a blade according to an arrow III in FIG. 1,
[0024] FIG. 3 shows a sectional view of the blade in the region of
a shroud according to the sectional lines IV in FIG. 2,
[0025] FIG. 4 shows a view in the axial direction of the blade in
the region of the shroud according to an arrow V in FIG. 2,
[0026] FIG. 5 shows a view, as in FIG. 4, but in another
embodiment,
[0027] FIG. 6 shows a view, as in FIG. 4, but in a further
embodiment,
[0028] FIG. 7 shows a view in the circumferential direction of a
blade in the region of the shroud,
[0029] FIG. 8 shows a view, as in FIG. 2, but in another
embodiment,
[0030] FIG. 9 shows a sectional view of the blade from FIG. 8 in
the region of the shroud according to the sectional lines IX in
FIG. 8,
[0031] FIG. 10 shows a greatly simplified basic cross section
through a turbo machine in the region of a blade row,
[0032] FIG. 11 shows a view in the radial direction in the region
of a blade according to an arrow XI in FIG. 10,
[0033] FIG. 12 shows a longitudinal section through the blade in
the region of a shroud ring according to the sectional lines XIV in
FIG. 11,
[0034] FIG. 13 shows an axial view of the blade in the region of
the shroud ring according to an arrow XIII in FIG. 11, and
[0035] FIG. 14 shows a view in the circumferential direction of the
blade in the region of the shroud ring according to an arrow XIV in
FIGS. 10, 11 and 13.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0036] According to FIG. 1, a turbo machine 1 is equipped with a
rotor 2 and with a stator 3. The rotor 2 is mounted rotatably in
the stator 3 in the usual way. The turbo machine 1 may basically be
a compressor or a turbine. Where a turbine is concerned, it may be
a steam turbine or a gas turbine. The turbo machine 1 may be
stationary and serve, for example, for driving a generator in a
power plant. The turbo machine 1 may likewise be a drive assembly
in a vehicle, in particular in an aircraft. However, an
implementation of the invention in a configuration of the turbo
machine 1 as a stationary gas turbine is preferred.
[0037] The rotor 2 has, according to FIG. 1, at least one moving
blade row 4 which include a plurality of moving blades 5. The cross
section according to FIG. 1 lies in the region of such a moving
blade row 4, although only a single moving blade 5 is illustrated
for the sake of clarity.
[0038] Moreover, the turbo machine 1 is equipped at least with a
shroud 8. This shroud 8 is in this case assigned to the moving
blade row 4, specifically for all the moving blades 5 of the moving
blade row 4. In the embodiment shown in FIG. 1, the shroud 8 is
assigned to the moving blade row 4 and is consequently arranged at
the outer ends, remote from the rotor 2, of the moving blades
5.
[0039] According to principles of the present 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 shroud plates 34. In this
case, the shroud ring 32 is assigned jointly to all the moving
blades 5 of the moving blade row 4. In contrast to this, the
respective shroud segment 33 is assigned simultaneously to a
plurality of adjacent moving blades 5 of the moving blade row 4,
while the respective shroud plate 34 is assigned in each case to a
single moving blade 5 of the moving blade row 4. The shroud ring
32, the shroud segments 33, and the shroud plates 34 have in common
the fact that they in each case form components which are separate
with respect to the moving blades 5 and which are fastened to the
moving blades 5 in a suitable way. FIG. 1 in each case indicates
only a single shroud segment 33; likewise, only a single shroud
plate 34 is also indicated by way of example. Although the
following description refers explicitly only to the shroud ring 32,
it nevertheless implicitly also applies correspondingly to the
embodiments with shroud segments 33 or to the embodiments with
shroud plates 34.
[0040] The shroud ring 32 is preferably produced from one piece,
for example by casting or forging. An embodiment is likewise
possible in which the shroud ring 32 is assembled from a plurality
of portions, in particular from a plurality of ring segments. The
shroud ring 32 extends, closed, that is to say without
interruption, in the circumferential direction indicated by an
arrow 9. The shroud ring 32 is configured to be self-supporting at
least insofar as it can be handled as a whole, thus simplifying its
mounting and demounting. Furthermore, it can at least partially
absorb and discharge in the circumferential direction the high
centrifugal forces arising during operation, thus reducing the load
on the moving blades 5 connected to it. The shroud ring 33 forms a
separate component which is produced independently of the moving
blades 5 and, for mounting, is built onto the moving blades 5. For
this purpose, the shroud ring 32 and the moving blades 5 are
fastened to one another by anchorings 10. The shroud segments 33
used, if appropriate, for forming the shroud 8 are also fastened to
at least one of the assigned moving blades 5, preferably to all the
assigned moving blades 5, by anchorings 10 of this type.
Correspondingly, in the event that the shroud 8 is formed from the
shroud plates 34, the individual shroud plates 34 are in each case
fastened to the in each case assigned moving blade 5 by anchorings
10 of this type. These anchorings 10 are in this case configured
such that they act at least in the radial direction, that is to say
can transmit tensile forces between the shroud ring 32 and the
moving blades 5 in the radial direction. Moreover, the anchorings
10 are configured such that they are non-destructively releasable.
In other words, the mounted shroud ring 32 can be demounted,
without the shroud ring 32 being destroyed and without the moving
blades 5 being destroyed. This is a critical cost benefit for the
later mounting of a repaired or of a new shroud ring 32.
[0041] The anchorings 10 can also be configured such that the
shroud ring 32, in the mounted state, is fixed with respect to the
moving blades 5 in the circumferential direction 9 and/or in the
axial direction, that is to say parallel to the axis of rotation 11
of the rotor. A defined fixing of the shroud ring 32 in position in
relation to the associated moving blades 5 is thereby achieved.
Preferred embodiments for implementing the anchoring 10 are
explained in more detail below.
[0042] Preferably, the shroud ring 32 is fastened to all the moving
blades 5 of the associated moving blade row 4 in each case by at
least one such anchoring 10. It is likewise basically possible that
the shroud ring 32 is fastened to only some moving blades 5,
preferably arranged so as to be symmetrically distributed
circumferentially, in each case by at least one such anchoring 10.
The anchorings 10 are in each case arranged radially between the
shroud ring 32 and the respective moving blade 5.
[0043] Basically, an anchoring 10 of this type may be configured in
any desired way, for example as a screw, as long as it is suitable
for the transmission of tensile force. A preferred configuration of
the anchoring 10 is explained in more detail below.
[0044] According to FIGS. 2 to 6, each anchoring 10 is equipped
with at least one anchor receptacle 12 and 13 and also with at
least one anchor 14 and 15 complementary to the respective anchor
receptacle 12, 13. FIGS. 2 to 4, 6, 8, and 9 in this case show an
anchor receptacle 12 located on the shroud side, that is to say
formed in the shroud ring 32, while FIGS. 5 and 6 show an anchor
receptacle 13 located on the blade side, that is to say formed in
the respective moving blade 5. The anchor cooperating with the
shroud-side anchor receptacle 12 is designated by 14, while the
anchor cooperating with the moving blade-side receptacle 13 is
designated by 15. In the shroud-side anchor receptacle 12, the
associated reception profile 16 is open toward the associated
moving blade 5. In contrast to this, in the blade-side anchor
receptacle 13, the reception profile 16 is open toward the shroud
ring 32. The anchor receptacles 12, 13 and their longitudinal
directions extend rectilinearly by way of example; embodiments with
curved longitudinal directions are likewise possible. Where
straight longitudinal directions are concerned, longitudinal edges
of the anchor receptacles 12, 13 may run parallel to one another.
The longitudinal edges may likewise be leaned or inclined with
respect to one another, as a result of which the anchor receptacles
12, 13 taper conically in the mounted direction. Where curved
longitudinal directions are concerned, the longitudinal edges may
extend along concentric circle arcs. It is likewise possible to
have longitudinal edge profiles along circle arcs with offset
circle centers in which a conical narrowing in the mounting
direction is obtained again for the anchor receptacles 12, 13.
[0045] The anchor receptacles 12, 13 are characterized by a
reception profile 16 which is constant or conical in its
longitudinal direction. This reception profile 16 has at least one
undercut 17 accessible radially to engagement. In the exemplary
embodiments shown, the reception profile 16 is a T-profile. Other
suitable contours, for example a dovetail profile, may likewise
serve as reception profiles 16.
[0046] The respective anchor 14, 15 has on its outside an anchor
profile 18 which is shaped complementarily to the respective
reception profile 16. In the present example, therefore, the anchor
profiles 18 are fitting T-profiles. In the mounted state, the
respective anchor 14, 15 is inserted into the associated anchor
receptacle 12, 13, specifically such that its anchor profile 18
effects engagement with the at least one undercut 17 of the
reception profile 16. Thus, a form fit active in the radial
direction, which is suitable for the transmission of very high
forces, is implemented between the shroud ring 32 and the
respective moving blade 5.
[0047] In the embodiments shown in FIG. 2 to 4 and 8, 9, the anchor
14 is configured as an integral part of the respective moving blade
5. This anchor 14 therefore projects in the radial direction from
the blade head, not designated in any more detail, of the
respective moving blade 5. In contrast to this, FIG. 5 shows an
alternative embodiment, in which the anchor 15 forms an integral
part of the shroud ring 32 and consequently projects radially from
the latter on a side facing the moving blade 5.
[0048] FIG. 6 shows another advantageous embodiment, in which the
anchoring 10 has an additional component, to be precise an anchor
body 31, which constitutes a separate component with respect to the
shroud ring 32 and to the respective moving blade 5. This anchor
body 31 is provided with two anchors 14, 15 or is configured such
that it has the two anchors 14, 15. Correspondingly, in this
embodiment, the anchoring 10 includes both the shroud-side anchor
receptacle 12 and the blade-side anchor receptacle 13. The two
anchor receptacles 12, 13 are in this case arranged such that they
lie radially opposite one another and, in particular, are radially
in alignment with one another. Preferably, the two anchor
receptacles 12, 13 are designed and arranged congruently to one
another. The anchor body 31, here, possesses a double-T-profile or
an H-profile. In the mounted state, then, the anchor body 31 is in
engagement via its two anchors 14, 15 with both anchor receptacles
12, 13. This embodiment may be advantageous in terms of mounting
and demounting, since, for example, it makes it easier to position
the shroud ring 32 on the moving blades 5.
[0049] In the embodiments of FIG. 2 to 6, the respective anchor
receptacle 12, 13 is in each case arranged such that its
longitudinal direction extends axially, that is to say parallel to
the axis of rotation 11. With such an orientation of the anchor
receptacles 12, 13, the anchoring 10 possesses a relatively small
length in the longitudinal direction of the anchor receptacle 12,
13. In the case of the axial orientation of the anchor receptacle
12, 13, the anchoring 10 can additionally transmit circumferential
forces between the shroud ring 32 and the respective moving blades
5. The mounting of the shroud ring 32 on the moving blades 5 in
this case takes place by the respective anchor 14, 15 being
introduced into the associated anchor receptacle 12, 13 in its
longitudinal direction. The longitudinal direction of the anchor
receptacle 12, 13 therefore corresponds to the mounting direction
of the anchoring 10. For mounting the anchoring 10, therefore, the
reception profile 17 is open at least on one side in the
longitudinal direction of the associated anchor receptacle 12,
13.
[0050] In the embodiment shown in FIGS. 8 and 9, the anchoring 10
is configured such that the anchor receptacle 12 has an inclination
with respect to the axial direction, represented by an arrow 19.
Correspondingly, the longitudinal direction of the anchor
receptacle 12 extends at an inclination with respect to the axial
direction 19. An angle of inclination is in this case designated by
20. Owing to the inclined orientation of the anchor receptacle 12,
the anchoring 10 can additionally also transmit axial forces
between the shroud ring 32 and the respective moving blade 5.
[0051] For the transmission of axial forces, the anchor receptacles
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 anchor 14 in the anchor
receptacle 12. In this embodiment, therefore, the reception profile
17 of the anchor receptacle 12 is closed on one side, for example
on the inflow side, in the longitudinal direction of the anchor
receptacle 12. Basically, the reception profile 17 of the
respective anchor receptacle 12, 13 may be open on both sides in
the longitudinal direction of the anchor receptacle 12, 13.
[0052] FIG. 8 shows a special embodiment in which the longitudinal
direction of the anchor receptacle 12 is inclined, for example, in
the same way as the blade profile 22. The angle of inclination 20
in this case lies, for example, in the region of a pitch angle, not
designated in any more detail, of the blade profile 22, which is
spanned between the inflow direction indicated by an arrow 23 and a
longitudinal direction, running through an inflow edge 24 and an
outflow edge 25, of the blade profile 22. In this embodiment, a
particularly large length, which may be advantageous for mounting,
is obtained for the anchoring 10 in its mounting direction, that is
to say parallel to the longitudinal direction of the anchor
receptacle 12. At the same time, the anchoring 10 can thereby be
integrated largely into the outer contour of the respective moving
blade 5. Its blade head therefore has to be enlarged only
comparatively insignificantly by a thickened cross section. The
region with a thickened cross section is indicated in FIG. 3 by a
curly bracket and is designated by 26. The anchoring 10 therefore
has a comparatively slender build.
[0053] The relatively large length of the anchoring 10 in the
longitudinal direction of the blade profile 22 according to the
embodiment shown in FIG. 8, like the relatively large width of the
anchoring 10 parallel to the longitudinal direction of the blade
profile 22 according to the other embodiments, has the effect, in
the case of a distortion of the respective moving blade 5 when the
turbo machine is in operation, of a tilting of the anchor 14, 15 in
the respective anchor receptacle 12, 13. This tilting leads, in
turn, to a nonpositive connection which reinforces the holding
force between the shroud ring 32 and the respective moving blade
5.
[0054] In an advantageous development, there may be provision for
securing the respective anchor 14, 15 in the associated anchor
receptacle 12, 13 by a shrink fit, thus leading to a prestressed,
nonpositive coupling between the shroud ring 32 and the respective
moving blade 5.
[0055] The respective anchoring 10 may be configured, by an
appropriate coordination of the anchor receptacle 12, 13 and of the
anchor 14, 15, as a sliding fit which makes mounting easier
parallel to the longitudinal direction of the anchor receptacle 12,
13. In this case, it may be expedient to equip the respective
anchoring 10 with a securing device 35. This securing device 35 is
in this case configured such that, in the mounted state of the
shroud ring 32, it fixes the relative position between the anchor
receptacle 12, 13 and anchor 14, 15 within the respective anchoring
10. For example, the securing device 35 may be formed by a
pin-shaped securing element 36 which extends transversely with
respect to the longitudinal direction of the anchor receptacle 12,
13, preferably radially. In the embodiments of FIGS. 4 and 5, this
securing element 36 penetrates with a positive fit in each case, on
the one hand, into a first orifice, not designated in any more
detail and formed in the shroud ring 32, and, on the other hand, at
the same time into a second orifice, not designated in any more
detail and formed in the respective moving blade 5. In the
embodiment according to FIG. 6, the securing element 32
additionally penetrates through the anchor member 31 in a through
orifice formed in the latter and not designated in any more
detail.
[0056] As may be gathered from FIGS. 4 to 6, in special embodiments
the shroud ring 32 may contain cooling duct structures 27 which are
indicated here merely diagrammatically by broken lines. These
cooling duct structures 27 serve for cooling the shroud ring 32 and
may, for example, form a coolant path remaining inside the shroud
ring 32 and/or have outlet orifices 28 which end on the surface of
the shroud ring 32 and through which coolant can emerge also in
order to form a cooling film on the surface of the shroud ring 32.
In the mounted state, the cooling duct structures 27 of the shroud
ring 32 communicate with cooling duct structures 29 which are
formed inside the respective moving blade 5. Thus, the cooling duct
structures 27 of the shroud ring 32 are supplied with coolant via
the cooling duct structures 29 of the respective moving blade 5. In
this case, the separate type of construction of the shroud ring 32
independent of the moving blades 5 is beneficial to the formation
of complex cooling duct structures 27 in the shroud ring 32, since
these can be produced in the shroud ring 32 before mounting on the
moving blades 5.
[0057] In this case, it is clear that suitable sealing devices, not
illustrated here, may be provided in the contact region between the
shroud ring 32 and the respective moving blades 5, in order to
connect the shroud-side cooling duct structures 27 to the
blade-side cooling duct structures 29 so as to be outwardly,
fluidly sealed off.
[0058] According to FIG. 7, in an exemplary development, the shroud
ring 32 may be equipped with a sealing structure 30. This is, in
this case, arranged on a side of the shroud ring 32 which faces
away from the moving blades 5. The sealing structure 30 is likewise
indicated here merely by a broken line and has, for example, the
form of a radially projecting peripheral web closed in the
circumferential direction 9, what is known as a fin. The sealing
structure 30 then cooperates with a radially adjacent wall either
of the rotor 2 or of the stator 3 in order to form an axial seal of
the respective moving blade row 4. For example, the web indicated
in FIG. 7 penetrates into a corresponding annular groove in order
thereby to generate the action of a labyrinth seal. There are many
models in the prior art for the configuration of sealing structures
30 of this type, and therefore they do not have to be dealt with in
any more detail here. Other sealing structures 30 are, for example,
a brushing structure which cooperates with a brushable
counterstructure, 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.
[0059] According to FIGS. 10 to 14, a possible embodiment of the
shroud 8 as a shroud ring 108 is described.
[0060] According to FIG. 10, a turbo machine 101 is equipped with a
rotor 102 and with a stator 103. The rotor 102 is mounted rotatably
in the stator 103 in the usual way. The turbo machine 101 may
basically be a compressor or a turbine. The turbo machine 101 may
be stationary and, for example, serve for driving a generator in a
power plant. The turbo machine 101 may likewise basically be a
drive assembly in a vehicle, in particular in an aircraft. However,
it is preferred to implement the invention in a configuration of
the turbo machine 101 as a stationary gas turbine.
[0061] According to FIG. 10, the rotor 102 has at least one moving
blade row 104 which includes a plurality of moving blades 105. The
cross section according to FIG. 10 lies in the region of such a
moving blade row 104, although only a single moving blade 105 is
illustrated for the sake of clarity.
[0062] According to principles of the invention, then, the turbo
machine 101 may be equipped at least with a shroud ring 108. This
shroud ring 108 is in this case assigned to one of the moving
blades row 104, specifically jointly for all the moving blades 105
of the respective moving blade row 104. In the embodiment shown in
FIG. 10, the shroud ring 108 is assigned to the moving blade row
104 and is therefore arranged at the outer ends, remote from the
rotor 102, of the moving blades 105.
[0063] The shroud ring 108 is in this case preferably produced from
one piece, for example by casting or forging. An embodiment is
likewise possible in which the shroud ring 108 is assembled from a
plurality of portions, in particular from a plurality of ring
segments.
[0064] The shroud ring 108 is a separately produced component with
respect to the moving blades 105. As a result, an optimization of
the shroud ring 108 in terms of strength, by an appropriate choice
of material and in terms of aerodynamics by means of appropriate
shaping, can be implemented.
[0065] The shroud ring 108 extends, closed, that is to say without
interruption, in the circumferential direction indicated by an
arrow 109. The shroud ring 108 has a self-supporting configuration,
with the result that it can absorb in it the forces arising during
operation. This property is of enhanced interest particularly in
the variant according to FIG. 10, since high centrifugal forces
arise there during operation as a result of the rotation of the
rotor 102. Furthermore, the shroud ring 108 forms a separate
component which is produced independently of the moving blades 105
and, for mounting, is built onto the moving blades 105. For this
purpose, the shroud ring 108 and the moving blades 105 are coupled
to one another in the coupling regions 1010.
[0066] These coupling regions 1010 may in this case be configured
such that, in the mounted state, the shroud ring 108 is radially
free with respect to the moving blades 105. Thus, in the embodiment
according to FIG. 10, the shroud ring 108 can increase its diameter
due to the active centrifugal forces and because of thermal
expansion, without tensile forces thereby being introduced into the
moving blades 105. Furthermore, the coupling regions 1010 may also
be configured such that, in the built-on state, the shroud ring 108
is fixed with respect to the moving blades 105 in the axial
direction, that is to say parallel to the axis of rotation 1011 of
the rotor 102, and, additionally or alternatively, in the
circumferential direction 109. A defined fixing in position of the
shroud ring 108 in relation to the associated moving blades 105 is
thereby achieved. A preferred embodiment for implementing the
radial freedom and the axial and tangential securing of the shroud
ring 108 in relation to the moving blades 105 is explained in more
detail below with reference to FIGS. 11 and 12.
[0067] According to FIGS. 11 and 12, the shroud ring 108 may be
secured with the aid of a securing device 1012 to at least one of
the moving blades 105 assigned to the shroud ring. Basically, the
shroud ring 108 can be attached to each moving blade 105 by at
least one such securing device 1012. FIGS. 11 and 12 in this case
illustrate two different variants of the securing device 1012 and
1012' which can be implemented cumulatively or alternatively. The
respective securing device 1012, 1012' is characterized in that it
secures the shroud ring 108 to the respective moving blade 105 in
the axial direction and/or in the circumferential direction 109
against relative adjustments, that is to say implements the
abovementioned fixing. The respective securing device 1012, 1012'
is in this case formed radially between the shroud ring 108 and the
respective moving blade 105.
[0068] For this purpose, in the preferred embodiment shown here,
the securing device 1012, 1012' is equipped with at least one
securing member 1013 or 1013'. The securing member 1013, 1013' is
arranged radially movably on the respective moving blade 105. For
this purpose, for example, it is mounted adjustably, guided in the
radial direction, in a correspondingly shaped guide orifice 1014 or
1014'.
[0069] The two securing devices 1012, 1012', which are reproduced
here by way of example, differ from one another, for example, in
the form of their securing members 1013, 1013'. Whereas one
securing member 1013 is configured as a cylindrical bolt, the other
securing member 1013' is in the form of a rectilinear web which
extends between an inflow edge, not designated in any more detail,
of the blade profile and an outflow edge, not designated in any
more detail, of the blade profile.
[0070] The respective securing device 1012, 1012' includes, for
each securing member 1013, 1013', an associated securing orifice
1015 or 1015' which is formed on the shroud ring 108 and is
arranged in alignment with the guide orifice 1014, 1014'. The
respective securing orifice 1015, 1015' is in this case coordinated
with the associated securing member 1013, 1013' such that the
securing member 1013, 1013' can penetrate in the radial direction
into the associated securing orifice 1015, 1015'. As soon as the
securing member 1013, 1013' projects so far out of its guide
orifice 1014, 1014' that it projects into the securing orifice
1015, 1015', the desired fixing or securing in the axial direction
and in the circumferential direction is obtained. Both the guide
orifices 1014, 1014' and the securing orifices 1015, 1015' are
shaped complementarily to the respective securing member 1013,
1013'.
[0071] Since the respective securing member 1013, 1013' is mounted
radially movably both in the associated guide orifice 1014, 1014'
and in the associated securing orifice 1015, 1015', the radial
degree of freedom for the shroud ring 108 in relation to the moving
blade 105 is thereby ensured at the same time.
[0072] In the case of the shroud ring 108 assigned to the moving
blade row 104, the penetration of the securing member 1013, 1013'
into the securing orifice 1015, 1015' takes place, when the turbo
machine 101 is in operation, as a result of the prevailing
centrifugal forces, since these drive the securing member 1013,
1013' radially outward, that is to say into the respective securing
orifice 1015, 1015'. The dimensioning of the respective securing
orifice 1015, 1015' is in this case expediently selected such that,
when a radial stop, not designated in any more detail, is reached,
the securing member 1013, 1013' is still arranged partially in the
guide orifice 1014, 1014'.
[0073] So that the desired securing action or fixing action can
likewise be ensured when the turbo machine 101 is at a standstill,
the securing member 1013, 1013' may be prestressed radially in the
direction of the securing orifice 1015, 1015' with the aid of a
securing spring 1016 or 1016'. Moreover, during the mounting of the
shroud ring 108, the radially prestressed securing member 1013,
1013' ensures an audible latching when the predetermined relative
position between the shroud ring 108 and the associated moving
blade 105 is reached.
[0074] 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 identified in FIG. 12 by a curly bracket and is
designated by 1017.
[0075] According to a preferred embodiment, the mounting of the
shroud ring 108 expediently takes place such that the shroud ring
108, once mounted, can, if required, be removed from the moving
blades 105 again non-destructively. This non-destructive release
from the moving blades 105 can be implemented particularly simply
in the embodiment shown here, which works to secure or to fix by
the securing device 1012, 1012'. For example, the shroud ring 108
contains for each securing member 1013, 1013' at least one
unlocking orifice 1018 or 1018'. This unlocking orifice 1018, 1018'
is in this case positioned such that the respective securing member
1013, 1013' can be driven through it out of the securing orifice
1015, 1015', using a suitable tool capable of being introduced into
the unlocking orifice 1018, 1018'. The respective securing member
1013, 1013' can thus be adjusted in the guide orifice 1014, 1014',
counter to the securing spring 1016, 1016', until the shroud ring
108 is freed from the respective moving blade 105.
[0076] According to FIG. 13, in a special embodiment, the shroud
ring 108 may contain cooling duct structures 1019 which are
indicated here merely diagrammatically by broken lines. These
cooling duct structures 1019 serve for cooling the shroud ring 108
and, for example, may form a coolant path remaining inside the
shroud ring 108 and/or may include outlet orifices 1020 which end
on the surface of the shroud ring 108 and through which coolant can
emerge also in order to form a cooling film on the surface of the
shroud ring 108. In the mounted state, the cooling duct structures
1019 of the shroud ring 108 communicate with cooling duct
structures 1021 which are formed inside the respective moving blade
105. Thus, the cooling duct structure 1019 of the shroud ring 108
is supplied with coolant via the cooling duct structures 1021 of
the respective moving blade 105. In this case, the separate type of
construction of the shroud ring 108 independent of the moving
blades 105 is beneficial to the formation of complex cooling duct
structures 1019 in the shroud ring 108, since these can be produced
in the shroud ring 108 before mounting on the moving blades 105. It
is clear that suitable sealing devices may be provided for the
fluidic coupling of the shroud-side cooling duct structures 1019 to
the blade-side cooling duct structures 1021.
[0077] According to FIG. 14, in a development of the invention, the
shroud ring 108 may be equipped with a sealing structure 1022. This
is in this case arranged on a side of the shroud ring 108 which
faces away from the moving blades 105. The sealing structure 1022
is likewise indicated here merely by a broken line and, for
example, has the form of a radially projecting peripheral web
closed in the circumferential direction, what is known as the fin.
The sealing structure 1022 then cooperates with a radially adjacent
wall either of the rotor 102 or of the stator 103 in order to form
an axial seal of the respective moving blade row 104. For example,
the web indicated in FIG. 14 penetrates into a corresponding
annular groove in order thereby to generate the action of a
labyrinth seal. There are many models in the prior art for the
configuration of sealing structures 1022 of this type, and
therefore they do not have to be dealt with in any more detail
here. Other sealing structures 1022 are, for example, a brushing
structure which cooperates with a brushable 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 SYMBOLS
[0078] 1 Turbo machine [0079] 2 Rotor [0080] 3 Stator [0081] 4
Moving blade row [0082] 5 Moving blade [0083] 6 Guide vane row
[0084] 7 Guide vane [0085] 8 Shroud [0086] 9 Circumferential
direction [0087] 10 Anchoring [0088] 11 Axis of rotation [0089] 12
Anchor receptacle [0090] 13 Anchor receptacle [0091] 14 Anchor
[0092] 15 Anchor [0093] 16 Reception contour [0094] 17 Undercut
[0095] 18 Anchor contour [0096] 19 Axial direction [0097] 20 Angle
of inclination [0098] 21 Stop [0099] 22 Blade profile [0100] 23
Inflow direction [0101] 24 Inflow edge [0102] 25 Outflow edge
[0103] 26 Thickened region of 5, 7 [0104] 27 Cooling duct structure
[0105] 28 Outlet orifice [0106] 29 Cooling duct structure [0107] 30
Sealing structure [0108] 31 Anchor body [0109] 32 Shroud ring
[0110] 33 Shroud segment [0111] 34 Shroud plate [0112] 35 Securing
device [0113] 36 Securing element [0114] 101 Turbo machine [0115]
102 Rotor [0116] 103 Stator [0117] 104 Moving blade row [0118] 105
Moving blade [0119] 106 Guide vane row [0120] 107 Guide vane [0121]
108 Shroud ring [0122] 109 Circumferential direction [0123] 1010
Coupling region [0124] 1011 Axis of rotation [0125] 1012, 1012'
Securing device [0126] 1013, 1013' Securing member [0127] 1014,
1014' Guide orifice [0128] 1015, 1015' Securing orifice [0129]
1016, 1016' Securing spring [0130] 1017 Thickened region of 105,
107 [0131] 1018, 1018' Unlocking orifice [0132] 1019 Cooling duct
structure in 108 [0133] 1020 Coolant outlet orifice [0134] 1021
Cooling duct structure in 105, 107 [0135] 1022 Sealing
structure
[0136] While the invention has been described in detail with
reference to exemplary embodiments thereof, it will be apparent to
one skilled in the art that various changes can be made, and
equivalents employed, without departing from the scope of the
invention. The foregoing description of the preferred embodiments
of the invention has been presented for purposes of illustration
and description. It is not intended to be exhaustive or to limit
the invention to the precise form disclosed, and modifications and
variations are possible in light of the above teachings or may be
acquired from practice of the invention. The embodiments were
chosen and described in order to explain the principles of the
invention and its practical application to enable one skilled in
the art to utilize the invention in various embodiments as are
suited to the particular use contemplated. It is intended that the
scope of the invention be defined by the claims appended hereto,
and their equivalents. The entirety of each of the aforementioned
documents is incorporated by reference herein.
* * * * *