U.S. patent application number 10/557527 was filed with the patent office on 2007-02-01 for bearing for axially mounting a rotor of a gas turbine, and gas turbine.
Invention is credited to Hajrudin Ceric, Andrija Duzic, Salvatore Pasqualino.
Application Number | 20070025839 10/557527 |
Document ID | / |
Family ID | 33041006 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070025839 |
Kind Code |
A1 |
Ceric; Hajrudin ; et
al. |
February 1, 2007 |
Bearing for axially mounting a rotor of a gas turbine, and gas
turbine
Abstract
The invention relates to a bearing for axially mounting a rotor
of a gas turbine. Said bearing comprises a bearing body that is
disposed stationary relative to the position of the rotor, a
hydraulic piston arrangement which is accommodated by the bearing
body, and a hydraulic system that is fluidically connected to the
hydraulic piston- arrangement. In order to create a bearing which
also absorbs bearing forces that occur due to high dynamic thrusts
of the rotor while ensuring secure mounting of the rotor, a
diaphragm is mounted between the hydraulic piston arrangement and
the hydraulic system.
Inventors: |
Ceric; Hajrudin;
(Oberhausen, DE) ; Duzic; Andrija; (Dusseldorf,
DE) ; Pasqualino; Salvatore; (Dusseldorf,
DE) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
33041006 |
Appl. No.: |
10/557527 |
Filed: |
April 20, 2004 |
PCT Filed: |
April 20, 2004 |
PCT NO: |
PCT/EP04/04175 |
371 Date: |
November 21, 2005 |
Current U.S.
Class: |
415/122.1 |
Current CPC
Class: |
F15B 20/007 20130101;
F16C 17/04 20130101; F05D 2240/52 20130101; F01D 25/168 20130101;
F16C 25/02 20130101; F16C 17/243 20130101; F05D 2240/53 20130101;
F01D 25/16 20130101; F16C 2360/23 20130101 |
Class at
Publication: |
415/122.1 |
International
Class: |
F01D 15/12 20060101
F01D015/12 |
Foreign Application Data
Date |
Code |
Application Number |
May 23, 2003 |
EP |
03011741.0 |
Claims
1-10. (canceled)
11. A bearing for axially mounting a rotor of a gas turbine,
comprising: a rotationally fixed bearing body that has a hydraulic
piston arrangement for axially displacing the rotor from a first
operating position into a second operating position; and a
hydraulic system fluidically connected to the hydraulic piston
arrangement, wherein to limit the displacement speed of the rotor,
at least one restrictor arranged in the bearing body and intended
for the hydraulic medium is provided between the hydraulic piston
arrangement and the hydraulic system.
12. The bearing as claimed in claim 11, wherein the restrictor is
formed by flow constrictions arranged in the bearing body and
without a line being interposed.
13. The bearing as claimed in claim 11, wherein the hydraulic
piston arrangement has a plurality of pistons arranged in
corresponding respective piston chambers.
14. The bearing as claimed in claim 11, wherein the piston chambers
are bores of cylindrical design.
15. The bearing as claimed in claim 11, wherein the piston chambers
are fluidically connected to one another.
16. The bearing as claimed in claim 11, wherein the hydraulic
piston arrangement is of annular design.
17. The bearing as claimed in claim 11, wherein two hydraulic
piston arrangements formed separately from one another are provided
and are arranged opposite one another on the bearing body.
18. The bearing as claimed in claim 17, wherein the two hydraulic
piston arrangements are fluidically connected to one another.
19. A bearing for axially mounting a rotor of a gas turbine,
comprising: a rotationally fixed bearing body that has a hydraulic
piston arrangement for axially displacing the rotor from a first
operating position into a second operating position; and a
hydraulic system fluidically connected to the hydraulic piston
arrangement, wherein to limit the displacement speed of the rotor,
at least one restrictor arranged in the bearing body and intended
for the hydraulic medium is provided between the hydraulic piston
arrangement and the hydraulic system and having two hydraulic
piston arrangements that are fluidically connected to one another
with a 4/2-way directional control valve interposed.
20. A gas turbine having a bearing, comprising: a rotationally
fixed bearing body that has a hydraulic piston arrangement for
axially displacing the rotor from a first operating position into a
second operating position; and a hydraulic system fluidically
connected to the hydraulic piston arrangement, wherein to limit the
displacement speed of the rotor, at least one restrictor arranged
in the bearing body and intended for the hydraulic medium is
provided between the hydraulic piston arrangement and the hydraulic
system.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is the US National Stage of International
Application No. PCT/EP2004/004175, filed Apr. 20, 2004 and claims
the benefit thereof. The International Application claims the
benefits of European Patent applications No. 03011741.0 EP filed
May 23, 2003, all of the applications are incorporated by reference
herein in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a bearing for axially mounting a
rotor of a gas turbine, having a rotationally fixed bearing body
which has a hydraulic piston arrangement for axially displacing the
rotor from a first operating position into a second operating
position, and having a hydraulic system fluidically connected to
the hydraulic piston arrangement. The invention also relates to a
gas turbine having such a bearing.
BACKGROUND OF THE INVENTION
[0003] Bearings of the aforesaid type are known per se from the
prior art. The bearing body of annular design preferably
surrounding the rotor of a gas turbine serves for the arrangement
of a plurality of hydraulic pistons. The latter are mounted against
stop surfaces formed on the rotor, so that the rotor is supported
in the axial direction.
[0004] Such a bearing for displacing the rotor of a gas turbine has
been disclosed by US 2002/0009361. Once the gas turbine and its
rotor have completely warmed up and thus the temperature-induced
material expansions have stopped, the rotor is displaced by means
of the bearing from a first operating position into a second
operating position against the direction of flow of the hot working
medium. As a result, in the turbine unit, the radial gaps formed
between the moving blade tips and guide rings opposite the latter
are minimized, so that a higher power output of the gas turbine is
achieved and the losses via the moving blade tips are
minimized.
[0005] The failure of hydraulic medium when the rotor is already
arranged in the second operating position causes the rotor to be
pushed back into the first operating position by the axial thrust
of the working medium, a factor which may lead to severe damage to
the axial bearing, the rotor and the gas turbine.
[0006] The position of the rotor can be set by the position of the
hydraulic pistons, which, depending on the set piston stroke, leads
to an adjustment of the rotor of the gas turbine in the axial
direction. The hydraulic piston arrangement therefore enables the
rotor of the gas turbine to be oriented in relation to the bearing
in accordance with the requirements and also enables it to be
displaced from a first working position into a second working
position. In a disadvantageous manner, however, the axial speed of
the rotor occurring during the displacement of the rotor produces
high dynamic forces, which may cause overloading of the bearing
body, of the bearing housing and of the gas turbine. As a result of
the axial displacement of the rotor, a total failure of the bearing
may therefore occur. In this case, the moving of the rotor in the
direction of flow is especially problematic, since very high
thrusts act on the rotor in this displacement direction.
[0007] In addition, DE 23 57 881 A1 and U.S. Pat. No. 4,915,510
have each disclosed an axial bearing which compensates for an
unintentional axial displacement, caused by changing axial thrusts,
of the rotor. Furthermore, DE 39 26 556 A1 shows a self-balancing
axial bearing for asymmetrical axial movements of the rotor.
SUMMARY OF THE INVENTION
[0008] Based thereon, an object of the invention, while avoiding
the aforesaid disadvantages, is to provide a bearing which absorbs
the bearing forces occurring as a result of high dynamic thrusts of
the rotor and ensures reliable mounting of the rotor. It is also an
object of the invention to specific a gas turbine in this
respect.
[0009] To achieve the first-mentioned object, the invention
proposes a bearing of the type described above which is
characterized in that, to limit the displacement speed of the
rotor, at least one restrictor for the hydraulic medium is provided
between hydraulic piston arrangement and hydraulic system.
[0010] Owing to the fact that a restrictor is interposed according
to the invention, the hydraulic medium displaced by the individual
pistons is first of all directed through the restrictor, a factor
which advantageously leads to a reduction in the kinetic energy and
to a comparatively slow displacement of the rotor. The loads acting
on the bearing body can thus be reduced, whereby the risk of
overloading is minimized. Even at a maximum force acting on the
rotor, kinetic energy can be sufficiently dissipated by the
restrictor arranged between hydraulic piston arrangement and
hydraulic system, so that overloading of the bearing as a result of
dynamic forces of the rotor is prevented. Reliable mounting of the
rotor of the gas turbine is thus ensured even during any possible
occurrence of high dynamic thrusts.
[0011] The restrictor is advantageously arranged in the bearing
body. Even in the unusual event of a line fracture in the hydraulic
system, the hydraulic medium can only flow off quickly to a limited
extent, which results in a low and thus non-damaging displacement
speed of the rotor. The bearing, rotor and gas turbine are thus
protected against defects which would be caused by an excessive
displacement speed of the rotor. In this case, the restrictors are
formed by flow constrictions.
[0012] In an advantageous development, the bearing can additionally
have at least one flow-control valve, designed as a restrictor,
between hydraulic piston arrangement and hydraulic system. This
protection likewise increases the safety of the entire system and
in addition makes it possible for the flow velocity of the
hydraulic medium and thus the displacement speed of the rotor to be
set.
[0013] Furthermore, in an advantageous development, the bearing can
have at least one flow-control valve, designed as a restrictor,
between hydraulic piston arrangement and hydraulic system. This
protection likewise increases the safety of the entire system and
in addition makes it possible for the flow velocity of the
hydraulic medium and thus the displacement speed of the rotor to be
set.
[0014] According to a further feature of the invention, provision
is made for the hydraulic piston arrangement to have a plurality of
pistons arranged in corresponding respective piston chambers. The
arrangement of a plurality of hydraulic pistons advantageously
achieves a more uniform introduction of force, which permits
rectilinear and positionally accurate moving of the rotor of the
gas turbine.
[0015] Furthermore, provision may be made with the invention for
the piston chambers to be bores of cylindrical design. Of course,
other geometrical configurations are also conceivable, but it has
been found that in particular piston chambers of cylindrical design
permit an optimized force distribution.
[0016] According to a special advantage of the invention, the
piston chambers are fluidically connected to one another. This
advantageously achieves a pressure balance between the individual
piston chambers, thereby achieving, firstly, a uniform load
distribution, but also, secondly, a uniformly rectilinear
displacement of the rotor of the gas turbine. The individual piston
chambers may in this case be fluidically connected to a common
pressure space via appropriately designed bores or else may be
fluidically connected to one another directly via appropriately
designed bores. It is crucial that a pressure balance can be
effected between the individual piston chambers.
[0017] According to a further feature of the invention, the
hydraulic piston arrangement is of annular design and surrounds the
rotor, of circular design in cross section, of the gas turbine. For
optimized transmission of force from the hydraulic pistons to the
rotor, the pistons are arranged equidistantly from one another with
respect to the hydraulic piston arrangement of annular design, so
that a uniform force distribution can be achieved. Depending on the
configuration and size of the hydraulic piston arrangement of
annular design, the common pressure space connecting the piston
chambers to one another may likewise be of annular design and may
surround the hydraulic piston arrangement.
[0018] According to a further feature of the invention, two
hydraulic piston arrangements formed separately from one another
are provided and are arranged opposite one another on the bearing
body. In this configuration of the bearing according to the
invention, the bearing body has a total of two hydraulic piston
arrangements, which, depending on the configuration, have in each
case a plurality of pistons. The pistons of the first hydraulic
piston arrangement interact with a first stop surface and the
pistons of the second hydraulic piston arrangement interact with a
second stop surface. During a displacement of the rotor of the gas
turbine, the pistons of the one hydraulic piston arrangement are
extended as a result of this arrangement described above, whereas
the pistons of the other hydraulic piston arrangement are
retracted. During a displacement of the rotor in the opposite
direction, a piston displacement of the hydraulic piston
arrangement is likewise effected in the opposite direction. With
respect to the thrust direction of the rotor, the one hydraulic
piston arrangement is designated as main track bearing and the
other hydraulic piston arrangement is designated as secondary track
bearing.
[0019] According to a further feature of the invention, the two
hydraulic piston arrangements, that is to say the main track
bearing and the secondary track bearing, are fluidically connected
to one another. The hydraulic medium displaced from one of the two
hydraulic piston arrangements as a result of a displacement of the
rotor can thus be used for the pressure buildup inside the other
hydraulic piston arrangement.
[0020] If the rotor of the gas turbine is displaced against the
thrust direction, a controlled shutdown of the gas turbine can no
longer be ensured in the event of a failure of the hydraulic medium
supply, for example due to a line fracture or the like. This is due
to the fact that the hydraulic piston arrangement of the secondary
track side of the bearing body, that is to say the secondary track
mounting, can no longer be supplied with hydraulic medium. In order
to be able to permit a specific shutdown of the gas turbine even in
the event of a failure of the hydraulic medium supply, it is
proposed according to a further feature of the invention that the
two hydraulic piston arrangements be fluidically connected to one
another with a 4/2-way directional control valve interposed. The
arrangement of such a directional control valve advantageously
makes it possible for hydraulic medium to be delivered from the
cylinder chambers of the main track side of the bearing body into
the cylinder chambers of the secondary track bearing even in the
event of a failure of the hydraulic medium supply. For this
purpose, the 4/2-way directional control valve is merely to be
switched into a de-energized position. As a result of the thrust of
the rotor of the gas turbine on the pistons of the main track
bearing, the hydraulic medium is then delivered from the piston
chambers of the hydraulic piston arrangement of the main track side
into the piston chambers of the secondary track bearing. A
controlled shutdown of the gas turbine can thus be ensured even in
the event of a failure of the hydraulic medium supply.
[0021] In an especially advantageous manner, a gas turbine has a
bearing having the aforesaid features.
BRIEF DESCRIPTION OF THE DRAWING
[0022] Further advantages and features of the invention follow from
the description with reference to FIG. 1, which shows in a partly
sectioned side view a bearing designed according to the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The bearing 1 according to the invention is shown in FIG. 1
in a partly sectioned side view. This bearing 1 serves to axially
mount and displace a rotor 8 of a gas turbine and comprises a
bearing body 2 which serves to accommodate a first hydraulic piston
arrangement 3 and a second hydraulic piston arrangement 4. With
respect to the thrust direction 7 of the rotor 8, the hydraulic
piston arrangement 3 is in this case arranged on the main track
side 5 and the hydraulic piston arrangement 4 is arranged on the
secondary track side 6 of the rotor 8.
[0024] Both the hydraulic piston arrangement 3 and the hydraulic
piston arrangement 4 are formed by a plurality of pistons 23 guided
in respective piston chambers 22. Via displaceably arranged
intermediate elements, the pistons 23 of the hydraulic piston
arrangement 3 act on the stop surface 24 formed on the rotor 8, and
the pistons 23 of the hydraulic piston arrangement 4 act on the
stop surface 25 likewise formed on the rotor 8, so that an axially
displaceable mounting of the rotor 8 overall is formed. Via the
arrangement of the hydraulic piston arrangements 3 and 4 in the
bearing body 2, the rotor 8, for example of a gas turbine, can be
positioned in a displaceable manner in the axial direction. For
this purpose, the piston chambers 22 can be selectively filled with
hydraulic medium, for example hydraulic oil, the hydraulic piston
arrangement 3 and the hydraulic piston arrangement 4 being
connected to a common hydraulic system 9 via the lines 10 and
11.
[0025] Components of the hydraulic system 9 are a tank 12, an
accumulator 13, a hydraulic pump 14, check valves 15, 16 and 17, a
2/2-way directional control valve 18, a 4/2-way directional control
valve 19 and adjustable flow-control valves 20 and 21. Restrictors
26 and 27 are provided between the hydraulic piston arrangements 3
and 4 and the hydraulic system 9. The restrictors 26, 27 are formed
by flow constrictions, arranged directly in the bearing body 2, for
the hydraulic medium without a line for hydraulic medium being
interposed. In addition, the flow-control valves 20, 21 serve as
further restrictors between the hydraulic piston arrangement 3 or
4, respectively, and the hydraulic system 9.
[0026] The movement of the rotor 8 is achieved by its axial
displacement relative to the bearing body 2 by hydraulic medium
being pumped either into the hydraulic piston arrangement 3 or into
the hydraulic piston arrangement 4. In the event of hydraulic
medium being forced into the hydraulic piston arrangement 3, the
pistons 23 extend in accordance with the filled quantity of
hydraulic medium and act on the stop surface 24 of the rotor 8 via
the elements arranged in between. This results in a displacement of
the rotor 8 against the thrust direction 7, that is to say from a
first operating position into a second operating position for
reducing the radial gaps known in the prior art, thus to the left
with respect to the image plane. Due to this longitudinal
displacement of the rotor 8, the stop surface 25 acts on the
hydraulic piston arrangement 4, and consequently hydraulic fluid is
displaced from the corresponding piston chambers 22 and is fed via
the line 11 to the hydraulic system 9.
[0027] According to the invention, in order to avoid a situation in
which the axial speed of the rotor 8 occurring during the
displacement of the rotor 8 produces excessive dynamic forces,
which could cause overloading of the bearing body 2, the
flow-control valves 20, 21 and restrictors 26, 27 embedded in the
bearing body 2 are interposed between hydraulic piston arrangement
3, on the one hand, and hydraulic piston arrangement 4, on the
other hand, and the hydraulic system 9. Even at a maximum force
during operation, said flow-control valves 20, 21 and restrictors
26, 27 can sufficiently dissipate kinetic energy to the rotor, so
that overloading of the bearing 1 as a result of the dynamic forces
of the rotor 8 is prevented.
[0028] During the loading which occurs during the faultless
operation of the gas turbine with an intended displacement of the
rotor 8, the adjustable flow-control valves 20, 21 limit the flow
velocity of the hydraulic medium to a predetermined value. The
displacement of the rotor 8 both in the thrust direction of the hot
gases and against the thrust direction is thus effected at the
predetermined comparatively slow speed.
[0029] In the event of a fault in the hydraulic system 9, in the
event of a failure of the flow-control valves 20, 21 or even in the
event of a line fracture of the line 10, 11, connected to the
bearing body 2, of the hydraulic system 9, the restrictors 26, 27
provided in the bearing body 2 limit the flow velocity of the
hydraulic medium. The unforeseen displacement, taking place in the
thrust direction 7, of the rotor 8 from the second operating
position back into the first operating position is then effected at
a speed which protects the bearing body 2 from damage and which may
be greater than the speed which is desired during faultless
operation and which is set by means of the flow-control valves.
[0030] The flow constrictions in the bearing body, which are formed
by the restrictors 26, 27, are calculated for an assumed maximum
load which is higher than the operating load.
[0031] The restrictors 26, 27 limit the displacement speed of the
rotor only in the event of a fault, whereas the flow-control valves
20, 21 limit the admissible displacement speed of the rotor during
an intended displacement of the latter.
[0032] Furthermore, provision is made according to the invention
for the hydraulic piston arrangement 3 and the hydraulic piston
arrangement 4 to be fluidically connected to one another via the
hydraulic system 9 with the 4/2-way directional control valve 19
arranged in between.
[0033] In addition, in bearing units previously known from the
prior art, it is not possible in the event of the failure of the
hydraulic medium supply in the case of a rotor displaced against
the thrust direction to ensure a controlled shutdown of the gas
turbine, since the hydraulic piston arrangement 4 on the secondary
track side 6 of the bearing 1 cannot be supplied with hydraulic
medium. This is remedied here by the 4/2-way directional control
valve arranged according to the invention in between main track
side 5 and secondary track side 6. This is because this 4/2-way
directional control valve can be switched into a de-energized
position in the event of the failure of the hydraulic medium
supply. To be precise, as a result of the thrust of the rotor 8 on
the pistons 23 of the hydraulic piston arrangement 3, hydraulic
medium is delivered from the piston chambers 22 of the main track
side 5 via the hydraulic system 9 into the piston chambers 22 of
the secondary track side 6. The pressure on the side of the
secondary track therefore builds up, so that, in the event of a
pressure drop, the rotor comes to a stop where it would likewise be
if the bearing were not hydraulically adjustable. As a result, an
emergency-running displacement of the rotor 8 can be achieved even
if the hydraulic medium supply is interrupted, and consequently a
controlled shutdown of the gas turbine remains possible.
* * * * *