U.S. patent application number 12/594353 was filed with the patent office on 2011-02-03 for arrangement for axially securing rotating blades in arotor, and gas turbine having such an arrangement.
Invention is credited to Darren T. Engle.
Application Number | 20110027092 12/594353 |
Document ID | / |
Family ID | 38372409 |
Filed Date | 2011-02-03 |
United States Patent
Application |
20110027092 |
Kind Code |
A1 |
Engle; Darren T. |
February 3, 2011 |
ARRANGEMENT FOR AXIALLY SECURING ROTATING BLADES IN AROTOR, AND GAS
TURBINE HAVING SUCH AN ARRANGEMENT
Abstract
An arrangement for axial locking of rotating blades in a rotor
is provided. The arrangement includes a shaft collar, a projection,
plate-like sealing elements, and a blocking element. The sealing
elements are provided for axially securing the rotating blades. At
least one sealing element has an opening for securing the sealing
elements against displacement in the circumferential direction. The
blocking element is inserted in a recess from the end side of the
shaft collar and blocks the displacement path of the sealing
element. In order for the blocking element to be secured against
unintentional releasing, the blocking element is fastened on the
rotor disk using plastic deformation.
Inventors: |
Engle; Darren T.; (Orlando,
FL) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
38372409 |
Appl. No.: |
12/594353 |
Filed: |
March 19, 2008 |
PCT Filed: |
March 19, 2008 |
PCT NO: |
PCT/EP2008/053271 |
371 Date: |
October 2, 2009 |
Current U.S.
Class: |
416/220R |
Current CPC
Class: |
F01D 5/3015 20130101;
F05B 2260/301 20130101 |
Class at
Publication: |
416/220.R |
International
Class: |
F01D 5/30 20060101
F01D005/30 |
Claims
1.-8. (canceled)
9. An arrangement for axial locking of rotor blades in a rotor,
comprising: a shaft collar; a projection, arranged on an end-face
side surface of the shaft collar in a region of a plurality of
rotor blade retaining slots; a plurality of plate-like sealing
elements; and a blocking element, wherein on an outer periphery of
the shaft collar the plurality of rotor blade retaining slots are
provided, each rotor blade retaining slot extends in an axial
direction of the rotor, wherein the plurality of rotor blades are
arranged in the shaft collar, each blade root corresponding to a
rotor blade retaining slot, wherein a radially outwardly open
encompassing slot is provided in the projection, wherein a radially
inwardly open locking slot is arranged in each rotor blade and lies
radially opposite the encompassing slot, wherein the plurality of
plate-like sealing elements are provided for axial locking of the
plurality of rotor blades, each rotor blade engages in the
encompassing slot and in the locking slot, forming an end-face
sealing ring in a circumferential direction, wherein at least one
of the plurality of sealing elements includes an opening for
securing the plurality of sealing elements against a displacement
in a circumferential direction, wherein a recess is disposed in a
side surface of the shaft collar, the recess approximately aligns
with the opening, wherein the blocking element is seated in the
recess and includes a bolt which projects on a first end face of
the blocking element and engages in the opening, and wherein the
blocking element is safeguarded against loss using caulking which
plastically deforms the blocking element.
10. The arrangement as claimed in claim 9, wherein the blocking
element includes a section that is formed in a shape of a wedge in
cross section in a region of the recess.
11. The arrangement as claimed in claim 10, wherein the recess is
formed corresponding to the wedge shape of the blocking element,
and wherein two sidewalls of the recess are inclined towards each
other as seen in a radially outward direction.
12. The arrangement as claimed in claim 9, wherein the recess is
open in the radially outward direction.
13. The arrangement as claimed in claim 12, wherein a plurality of
depressions are provided in the sidewalls of the recesses on the
circumferential side of the rotor, and wherein the blocking element
is at least partially introduced into the plurality of depressions
as a result of the plastic deformation.
14. The arrangement as claimed in claim 9, wherein the recess is
closed in the radially outward direction.
15. The arrangement as claimed in claim 9, wherein the shaft collar
is formed by a rotor disk.
16. The arrangement as claimed in claim 9, wherein at least every
other sealing element includes an opening for securing the
plurality of sealing elements against displacement.
17. The arrangement as claimed in claim 9, wherein a depression is
disposed in a second end-face of the blocking element, and wherein
the depression is used as a predetermined position at which a
chisel may be used to strike the blocking element in order to
assist in a caulking process.
18. A gas turbine, comprising: an arrangement, comprising: a shaft
collar, a projection, arranged on an end-face side surface of the
shaft collar in a region of a plurality of rotor blade retaining
slots, a plurality of plate-like sealing elements, and a blocking
element, wherein on an outer periphery of the shaft collar the
plurality of rotor blade retaining slots are provided, each rotor
blade retaining slot extends in an axial direction of the rotor,
wherein the plurality of rotor blades are arranged in the shaft
collar, each blade root corresponding to a rotor blade retaining
slot, wherein a radially outwardly open encompassing slot is
provided in the projection, wherein a radially inwardly open
locking slot is arranged in each rotor blade and lies radially
opposite the encompassing slot, wherein the plurality of plate-like
sealing elements are provided for axial locking of the plurality of
rotor blades, each rotor blade engages in the encompassing slot and
in the locking slot, forming an end-face sealing ring in a
circumferential direction, wherein at least one of the plurality of
sealing elements includes an opening for securing the plurality of
sealing elements against a displacement in a circumferential
direction, wherein a recess is disposed in a side surface of the
shaft collar, the recess approximately aligns with the opening,
wherein the blocking element is seated in the recess and includes a
bolt which projects on a first end face of the blocking element and
engages in the opening, and wherein the blocking element is
safeguarded against loss using caulking which plastically deforms
the blocking element.
19. The gas turbine as claimed in claim 18, wherein the blocking
element includes a section that is foamed in a shape of a wedge in
cross section in a region of the recess.
20. The gas turbine as claimed in claim 19, wherein the recess is
fanned corresponding to the wedge shape of the blocking element,
and wherein two sidewalls of the recess are inclined towards each
other as seen in a radially outward direction.
21. The gas turbine as claimed in claim 18, wherein the recess is
open in the radially outward direction.
22. The gas turbine as claimed in claim 21, wherein a plurality of
depressions are provided in the sidewalls of the recesses on the
circumferential side of the rotor, and wherein the blocking element
is at least partially introduced into the plurality of depressions
as a result of the plastic deformation.
23. The gas turbine as claimed in claim 18, wherein the recess is
closed in the radially outward direction.
24. The gas turbine as claimed in claim 18, wherein the shaft
collar is fanned by a rotor disk.
25. The gas turbine as claimed in claim 18, wherein at least every
other sealing element includes an opening for securing the
plurality of sealing elements against displacement.
26. The gas turbine as claimed in claim 18, wherein a depression is
disposed in a second end-face of the blocking element, and wherein
the depression is used as a predetermined position at which a
chisel may be used to strike the blocking element in order to
assist in a caulking process.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2008/053271, filed Mar. 19, 2008 and claims
the benefit thereof. The International Application claims the
benefits of European Patent Office application No. 07007088.3 EP
filed Apr. 4, 2007, both of the applications are incorporated by
reference herein in their entirety.
FIELD OF INVENTION
[0002] The invention refers to an arrangement for axial locking of
rotor blades in a rotor, with a shaft collar, on the outer
periphery of which provision is made for rotor blade retaining
slots which extend in the axial direction of the rotor and in which
rotor blades, with blade roots which correspond to the rotor blade
retaining slot, are arranged in each case, with a projection which
is arranged on an end-face side surface of the shaft collar in the
region of the retaining slots, in which projection a radially
outwardly open encompassing slot is provided and with radially
inwardly open locking slots which are arranged in each rotor blade
and which lie radially opposite the encompassing slot in each case,
wherein for axial locking of the rotor blades provision is made for
plate-like sealing elements which in each case engage in the
encompassing slot and in the locking slot, forming an end-face
sealing ring in the circumferential direction, wherein at least one
of the sealing elements has a means for securing the sealing
elements against displacement in the circumferential direction. In
addition, the invention refers to a gas turbine with such an
arrangement.
BACKGROUND OF INVENTION
[0003] Rotors of gas turbines are known in which turbine rotor
blades, which are arranged on the outer periphery in rotor blade
retaining slots, are secured against axial displacement by means of
sealing plates. In this case, to fasten these sealing plates on the
rotor by means of riveting is known for example from U.S. Pat. No.
3,957,393.
[0004] Furthermore, an arrangement according to FIG. 1 is known. It
shows a generic-type arrangement in a plan view, and FIG. 2 shows
an arrangement in a cross section according to the line of
intersection II-II in FIG. 1. For each rotor blade 14 which is to
be secured against axial displacement inside its rotor blade
retaining slot 12, two slightly overlapping sealing plates 16 are
provided as sealing elements which in each case cover by half the
end-face opening of the rotor blade retaining slot 12. Each sealing
plate 16 by its radially inner end 18 is inserted in an
encompassing slot 20 which is provided on a rotor disk 19 on the
end face, and by its radially outer end 22 is inserted in a locking
slot 24 which is provided on the underside 26 of a platform 28 of
the rotor blade 14. In order to secure each sealing plate 16
against displacement in the circumferential direction U, a
rectilinear metal strip 30, which extends essentially in the radial
direction of the rotor 23, is fastened on each sealing plate. Each
metal strip 30 terminates at its radially outer end 32 in a
uniformly converging point 34. Chamfered edges 36 are provided on
the platforms 28 of the rotor blades 14, wherein two oppositely
disposed edges 36 of directly adjacent turbine rotor blades 14 form
in each case a recess 38 which tapers to a point and into which the
point 34 of the metal strip 30 can project and abut for securing
the sealing plate 16 against displacement in the circumferential
direction U.
[0005] The sealing plates 16 furthermore cater for separation of
two regions 37, 39 in which on the one hand cooling air can enter
and on the other hand some of the hot gas can possibly enter.
[0006] For fastening the metal strip 30 on the sealing plate 16,
two parallel slots 40 are provided in the last-named, through which
the metal strip 30, which is already pre-bent into a U-shape, is
inserted. Before installing the sealing plate 16 on the rotor disk
19, the end 41 of the metal strip 30 opposite the point 34 is
already bent into the position which is shown in FIG. 2 for the
fastening of the metal strip 30.
[0007] After installing the rotor blades 14 in the rotor disks 19,
the sealing plates 16 with the pre-installed metal strips 30 are
threaded one after the other into the endlessly encompassing slot
20 which is arranged on the rotor disk 19, and into the locking
slot 24 which is arranged on the underside 26 of the platform 28.
The sealing plates 16 are positioned along the circumference of the
encompassing slot 20 so that each metal strip 30 lies opposite a
recess 38. The points 34 of the metal strips 30 are then bent into
the recesses 38 in order to exclude displacement of the sealing
plates 16 in the circumferential direction U.
[0008] Since the metal strips may be bent only once on account of
the enormously high mechanical requirements, when exchanging a
rotor blade in the event of a service the metal strip which is then
bent up is to be replaced by a new metal strip. Furthermore, the
slots which are provided for accommodating the metal strips in the
sealing plates weaken the said sealing plates.
SUMMARY OF INVENTION
[0009] It is the object of the present invention to disclose an
alternative arrangement for securing the sealing elements against a
rotating displacement in the circumferential direction, in which
the installation and removal times are improved. The provision of a
gas turbine with such an arrangement is a further object of the
invention.
[0010] The object which is focused upon the arrangement for axial
locking of rotor blades in a rotor is achieved by means of the
features of the claims.
[0011] The invention provides that in the case of the generic-type
arrangement the means for securing the sealing elements against
displacement in the circumferential direction comprise an opening
which is provided in the sealing element and also a recess which is
provided in the side surface of the shaft collar and approximately
aligns with the opening, and a positionally locked blocking element
which is seated in the recess and in the opening. The invention
avoids the previous configuration in which a metal strip which is
hooked into the sealing element engages in a form-fitting manner in
a recess. Instead of the metal strip, a blocking element is now
provided which can be inserted into the recess which is provided on
the shaft collar on the end face. The blocking element blocks
displacement of the sealing element in the circumferential
direction since, being arranged in the region of the sealing
element, it extends transversely to the encompassing slot in which
the sealing element is seated and in the process engages in the
opening which is provided on the sealing element. A negligible and
tolerable clearance of the sealing element along the encompassing
slot is possible only insofar as the width of the opening as seen
in the circumferential direction is larger than the width of the
blocking element which is to be considered in the circumferential
direction.
[0012] By using a blocking element which engages in the opening of
the sealing element and is fastened on the end face on the shaft
collar by means of caulking which plastically deforms the blocking
element, a particularly reliable and simple axial securing of the
sealing element against displacement in the circumferential
direction can be achieved. Furthermore, installation is to be
accomplished quickly and simply. For this purpose, the blocking
element is to be plastically deformed on the end face with a
suitable caulking tool, for example a tool in the style of a hammer
and chisel, so that it abuts in the recess under tension. As a
result, an exceptionally reliable frictional engagement between the
wall of the recess and the blocking element is brought about, which
reliably prevents the unwanted loosening of the blocking element
during operation of the gas turbine. For removing the blocking
element, the deformed region of the blocking element can be removed
by grinding and in this way the frictional engagement is loosened
for removal.
[0013] In addition, with the construction according to the
invention the slots which were provided for fastening the locking
plate on the sealing element and previously weakened the sealing
element are dispensed with. The rigidity of the sealing element is
subsequently further increased, also its sealing effect.
[0014] Advantageous developments are disclosed in the dependent
claims.
[0015] In an advantageous development of the invention, the
blocking element, with regard to its installed position, is formed
in the shape of a wedge in cross section in the region of the
recess and moreover comprises a bolt which projects on the end face
and which can be inserted into the opening of the sealing element.
As a result of the wedge shape of the blocking element and of the
recess which corresponds to the wedge shape a defined position of
the blocking element in the rotor is predetermined. Furthermore,
the orientation of the wedge shape of the recess is selected so
that the converging side walls point outwards, in the same way as
the flanks of the blocking element which correspond to them. As a
result, the wedge-shaped blocking element is braced outwards under
centrifugal force action and in the process wedges or jams further
in the recess which further increases the frictional engagement
between the flanks and the side walls and makes an unwanted
loosening of the blocking element more difficult. Consequently, a
particularly reliable arrangement can be disclosed as a result of
this.
[0016] According to an alternative development of the invention,
the recess which accommodates the blocking element is open as seen
in the radially outward direction. In this case, the blocking
element which is inserted therein can be plastically deformed on
the circumferential side, with regard to the rotor, instead of the
end-face deformation. As long as provision is then still made for
pockets which are additionally arranged in the sidewalls of the
recess on the circumferential side, into which parts of the
deformed material of the blocking element can deflect, a form-fit
for positional locking of the blocking element can additionally
also be provided in addition to the caulking of the blocking
element. As a result of this, the blocking element is especially
reliably safeguarded against loss.
[0017] According to a further advantageous development, the recess,
extending in the axial direction of the rotor, is arranged in the
side surface of the shaft ring in such a way that it extends right
into the encompassing slot. Weakening of the shaft collar or of a
rotor disk which preferably forms the shaft collar is avoided in
this case. Therefore, the opening which is provided on the sealing
element is then provided on the radial inner end of the sealing
element. This region of the sealing element heats up the least
during operation so that the rigidity and the temperature
resistance of the sealing element are not impaired as a result of
the opening.
[0018] It has been proved to be especially advantageous if every
other sealing element, or each sealing element, has the means for
securing the sealing elements against displacement. The arrangement
is expediently provided on a rotor of a stationary gas turbine
which is exposed to throughflow in the axial direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention is explained based on a plurality of exemplary
embodiments which are shown in a drawing. Further advantages and
features result from the explanation. In the drawing:
[0020] FIG. 1 shows the arrangement for axial locking of rotor
blades in a rotor according to the prior art,
[0021] FIG. 2 shows the cross-sectional view according to FIG. 1
along the line of intersection II-II,
[0022] FIG. 3 shows the detail of a plan view of a rotor disk with
a rotor blade arranged thereupon as an arrangement for axial
locking of the rotor blade by means of a sealing element,
[0023] FIG. 4 shows a perspective view of a blocking element
according to the invention, and
[0024] FIG. 5 shows a perspective view of a blocking element which
is inserted into the recess of the rotor according to a second
development.
DETAILED DESCRIPTION OF INVENTION
[0025] FIG. 3 shows a detail of the end-face plan view of the shaft
collar 21, which is formed by a rotor disk 19, of a rotor 23 of a
gas turbine. The rotor 23, which is rotatable around the rotational
axis 50, has rotor blade retaining slots 12 which are distributed
on its outer periphery 52 along the circumference U and extend in
the axial direction, into which slots a rotor blade 14, with a
blade root 54 which is constructed corresponding to the rotor blade
retaining slot 12, in each case can be inserted. A rotor blade 14
is already inserted in the rotor blade retaining slot 12 which is
shown in the middle in FIG. 3. As in the case of the prior art
which is shown in FIG. 1 and FIG. 2, a projection 58 or widening,
with a radially outwardly open encompassing slot 20 therein, which
extends in the axial direction, is arranged on an end face of the
rotor disk 19 or on an end-face side surface 56 of the shaft collar
21. The encompassing slot 20 for example is arranged radially
further inwards than the rotor blade retaining slots 12. The rotor
blade 14 has a platform 28 which is arranged between blade root 54
and the profiled blade airfoil and on the underside of which
provision is made for a locking slot 24 which is open towards the
encompassing slot 20 and in this case lies opposite this. In a
similar manner to the prior art, a sealing element 42 is inserted
into the endlessly encompassing slot 20 and in the locking slot 24
and secures the rotor blade 14 against displacement along the rotor
blade retaining slot.
[0026] In contrast to the nearest prior art, the sealing element 42
completely covers the end-face opening of one of the rotor blade
slots 12. In this way, only one of the rotor blades 14 is secured
in each case by one of the sealing elements 42 against displacement
along the rotor blade retaining slot 12.
[0027] The sealing elements 42, however, as in the case of the
prior art, can be distributed over the circumference so that two
directly adjacent sealing elements engage by half in the locking
slot 24 of the rotor blade 14 in each case. Then two adjacent
sealing elements secure one of the rotor blades 14 against axial
displacement.
[0028] Similar to the prior art, a completely installed ring of
sealing elements 42, which slightly overlap in each case, forms a
sealing ring which separates a region 37 which is exposed to
throughflow by a cooling medium from a further region 39 in which a
hot gas can possibly be encountered (FIG. 2).
[0029] In order to secure the sealing element 42 itself against
displacement in the circumferential direction, an opening 63, which
can be a cutout but also a hole, is provided on the radially inner
end 61 of the sealing element 42.
[0030] Furthermore, a recess 65, which extends essentially in the
axial direction of the rotor 23, i.e. parallel to its rotational
axis 50, is provided on the side surface 56 of the shaft collar 21
in the region of the projection 58 in each case. Each recess 65 has
two oppositely disposed side surfaces 66 which, as seen in the
outward direction, extend towards each other in a wedge-like
manner, but do not touch, forming a gap.
[0031] Instead of an outwardly open recess 65, an outwardly closed
recess can also be provided. In this case, the two side walls 66
which extend towards each other meet in a rounded point.
[0032] The blocking element 67 which is perspectively shown in FIG.
4 can be inserted into the recess 65. The blocking element 67
comprises a section with a wedge shape which corresponds to the
recess 65, with flanks 70 which extend towards each other, and a
bolt 69 which is arranged on the wedge-shaped section on the end
face. With the blocking element 67 inserted in the recess 65, its
bolt 69 engages in the opening 63 of the sealing element 42.
[0033] In total, therefore, the means for securing the sealing
element 42 against displacement in the circumferential direction U
comprises the opening 63 in the sealing element 42, the recess 65
which is arranged in the end face of the rotor disk 19, and also
the blocking element 67 which can be inserted into the recess.
[0034] A negligible and tolerable clearance of the sealing element
42 along the encompassing slot 20 is possible only insofar as the
width of the opening 63 as seen in the circumferential direction is
larger than the width or the diameter of the bolt which is to be
considered in the circumferential direction. In order to achieve an
especially impermeable separation of the region 37 from the region
39, the width of the opening 63 preferably corresponds essentially
to the diameter of the bolt 69.
[0035] After inserting the blocking element 67 in the recess 65,
the blocking element is slightly plastically deformed by means of a
caulking process. The blocking element 67 in this case is
plastically deformed in the region 71. As a result of this, the
still existing, but negligible, clearance for inserting the
blocking element 67 is removed so that a secure seating of the
blocking element 67 results. As a result of removing the clearance,
the flanks 70 are pressed onto the sidewalls 66. As a result of
this, a reliable frictional engagement is created between the walls
66 of the recess 65 and the flanks 70 of the blocking element 67
which reliably prevents the unwanted loosening of the blocking
element.
[0036] The caulking process can be carried out by means of a
suitable chisel which is slightly rounded at the point, which when
placed on the blocking element in the region 71 is provided with a
hammer blow. For controlled positioning of the chisel the blocking
element has an end-face premachined depression 71 in which the
chisel is to be placed.
[0037] An alternative development of the invention is shown
perspectively in FIG. 5. In this case, the blocking element 67
which is shown from FIG. 4 is inserted in the recess 65 with only a
slight alteration. Instead of the end-face depression 71 the
blocking element 67 which is to be used for FIG. 5 has two
depressions 71 on the generated surface side (circumferential
side), with regard to the rotor, as an aid for the caulking process
and which, providing the blocking element 67 is inserted in the
recess 65 according to FIG. 5, in each case lie opposite a pocket
72 which is provided in the sidewalls 66 on the circumferential
side. By means of a caulking process according to the aforesaid
manner the material of the blocking element which is adjacent to
the depressions 71 can be introduced into the pockets 72 so that a
form-fit results for secure positioning of the blocking element 67
in the recess 65.
[0038] In all, an arrangement is disclosed by the invention in
which the disadvantages which are known from the prior art are
eliminated by a blocking element, which is inserted from the end
face of the shaft collar into a recess, blocking the displacement
path of the sealing element. So that the blocking element itself is
secured against unwanted loosening this is fastened on the rotor
disk by means of plastic deformation.
* * * * *