U.S. patent application number 12/602891 was filed with the patent office on 2010-07-15 for turbine having compact inflow housing thanks to internal control valves.
Invention is credited to Walter Gehringer, Richard Geist.
Application Number | 20100178153 12/602891 |
Document ID | / |
Family ID | 38668641 |
Filed Date | 2010-07-15 |
United States Patent
Application |
20100178153 |
Kind Code |
A1 |
Gehringer; Walter ; et
al. |
July 15, 2010 |
Turbine Having Compact Inflow Housing Thanks to Internal Control
Valves
Abstract
A turbine having an inflow housing is provided. The turbine
includes an inlet for an inflowing working fluid, wherein the inlet
can be closed by a quick closing valve, a plurality of control
valves and at least two nozzle groups. The flow of the working
fluid is controllable by the inlet into the nozzle groups via the
control valves. Furthermore, the inlet can be connected via an
inlet line to the first nozzle group, wherein the inlet line is
guided through the primary control valve such that the flow of the
working fluid along the inlet line can be controlled using the
primary control valve. The secondary control valve connects the
first nozzle group to the second nozzle group such that the flow of
the working fluid from the first nozzle group into the second
nozzle group may be controlled using the secondary control
valve.
Inventors: |
Gehringer; Walter;
(Nurnberg, DE) ; Geist; Richard; (Lauf,
DE) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
38668641 |
Appl. No.: |
12/602891 |
Filed: |
April 25, 2008 |
PCT Filed: |
April 25, 2008 |
PCT NO: |
PCT/EP2008/055045 |
371 Date: |
December 3, 2009 |
Current U.S.
Class: |
415/1 ;
415/147 |
Current CPC
Class: |
F01D 17/145 20130101;
F01D 17/18 20130101 |
Class at
Publication: |
415/1 ;
415/147 |
International
Class: |
F01D 17/12 20060101
F01D017/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2007 |
EP |
07011268.5 |
Claims
1.-10. (canceled)
11. A turbine with an inflow housing, comprising: an inlet for an
inflowing working fluid, the inlet may be closed off by a quick
closing valve; a plurality of control valves; and at least two
nozzle groups, wherein the flow of working fluid may be controlled
from the inlet into the plurality of nozzle groups using the
plurality of control valves, wherein the inflow housing includes a
primary control valve and at least one secondary control valve,
wherein the inlet is connected via an inlet line to a first nozzle
group, wherein the inlet line is routed through the primary control
valve such that the flow of working fluid along the inlet line may
be controlled using the primary control valve, and wherein a first
secondary control valve connects the first nozzle group to the
second nozzle group such that the flow of the working fluid from
the first nozzle group into the second nozzle group may be
controlled using the first secondary control valve.
12. The turbine as claimed in claim 11, further comprising a third
nozzle group and a second secondary control valve, wherein the
second secondary control valve connects the second nozzle group to
the third nozzle group such that the flow of working fluid from the
second nozzle group into the third nozzle group may be controlled
using the second secondary control valve.
13. The turbine as claimed in claim 11, wherein the primary control
valve is equipped with a pilot valve.
14. The turbine as claimed in claim 11, wherein the turbine further
comprises a rotor supported to allow rotation in the inflow
housing, wherein the plurality of nozzle groups extend in a shape
of a ring sector at a common diameter around the rotor, wherein
each secondary control valve includes a shut-off facility and an
axis of actuation, and wherein the shut-off facilities of the
plurality of secondary control valves are arranged on the diameter
of the plurality of nozzle groups.
15. The turbine as claimed in claim 14, wherein the axes of
actuation of the plurality of secondary control valves extend
radially to a first axis of rotation of the rotor.
16. The turbine as claimed in claim 15, wherein the shut-off
facilities of the plurality of secondary control valves can be
switched rotationally so that the axis of actuation involved is a
second axis of rotation.
17. The turbine as claimed in claim 14, wherein the inflow housing
is essentially annular and is divided into at least two housing
halves, and wherein the inlet line is an integral component of a
first housing half.
18. The turbine as claimed in claim 11, wherein each nozzle group
is provided with a plurality of nozzles directed onto the rotor,
and wherein the plurality of nozzles are directed axially onto the
rotor so that the flow of working fluid through the turbine is in
parallel to the first axis of rotation.
19. The turbine as claimed in claim 11, wherein the inflowing
working fluid is steam.
20. The turbine as claimed in claim 11, further comprising a fourth
nozzle group and a third secondary control valve, wherein the third
secondary control valve connects the third nozzle group to the
fourth nozzle group such that the flow of working fluid from the
third nozzle group into the fourth nozzle group may be controlled
using the third secondary control valve.
21. A method for operating a turbine with an inflow housing,
comprising: opening a quick closing valve, the quick closing valve
is used to quickly close off an inlet for a working fluid flow;
opening a pilot valve of a primary control valve; finish opening
the primary control valve after the operating speed of the rotor is
reached; and opening the first secondary control valve, wherein an
inlet line is routed through the primary control valve such that
the working fluid flow along the inlet line may be controlled using
the primary control valve, and wherein the first secondary control
valve connects a first nozzle group to a second nozzle group such
that the working fluid flow from the first nozzle group into the
second nozzle group may be controlled using the first secondary
control valve.
22. The method as claimed in claim 21, wherein the method is used
during a start-up of the turbine.
23. The method as claimed in claim 21, further comprising a third
nozzle group and a second secondary control valve, wherein the
second secondary control valve connects the second nozzle group to
a third nozzle group such that the flow of working fluid from the
second nozzle group into the third nozzle group may be controlled
using the second secondary control valve.
24. The method as claimed in claim 21, wherein the primary control
valve is equipped with a pilot valve.
25. The method as claimed in claim 21, wherein the turbine further
comprises a rotor supported to allow rotation in the inflow
housing, wherein the plurality of nozzle groups extend in a shape
of a ring sector at a common diameter around the rotor, wherein
each secondary control valve includes a shut-off facility and an
axis of actuation, and wherein the shut-off facilities of the
plurality of secondary control valves are arranged on the diameter
of the plurality of nozzle groups.
26. The method as claimed in claim 25, wherein the axes of
actuation of the plurality of secondary control valves extend
radially to a first axis of rotation of the rotor.
27. The method as claimed in claim 26, wherein the shut-off
facilities of the plurality of secondary control valves can be
switched rotationally so that the axis of actuation involved is a
second axis of rotation.
28. The method as claimed in claim 25, wherein the inflow housing
is essentially annular and is divided into at least two housing
halves, and wherein the inlet line is an integral component of a
first housing half.
29. The method as claimed in claim 21, wherein each nozzle group is
provided with a plurality of nozzles directed onto the rotor, and
wherein the plurality of nozzles are directed axially onto the
rotor so that the flow of working fluid through the turbine is in
parallel to the first axis of rotation.
30. The method as claimed in claim 21, wherein the inflowing
working fluid is steam.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2008/055045, filed Apr. 25, 2008 and claims
the benefit thereof. The International Application claims the
benefits of European Patent Office application No. 07011268.5 EP
filed Jun. 8, 2007, both of the applications are incorporated by
reference herein in their entirety.
FIELD OF INVENTION
[0002] The present invention relates to a turbine with an inflow
housing which comprises an inlet for an inflowing working fluid,
wherein the inlet can be closed by a quick closing valve, a
plurality of control valves and at least two nozzle groups, the
flow of the working fluid being controllable from the inlet into
the nozzle groups via the control valves.
BACKGROUND OF INVENTION
[0003] This type of turbine is known from the publication DE 1 915
267 A1 of the same applicant. The inflow housing is the part of the
turbine housing into which the working fluid flows into the turbine
and in which the working fluid is directed onto the rotor. For
applying the fluid to the rotor the inflow housing has a number of
nozzle groups which extend in the shape of a ring sector at a
common diameter around the rotor. Each nozzle group combines a
number of nozzles which are directed onto the rotor. The inflowing
working fluid flowing in through the inlet is directed into the
nozzle groups, exits from the nozzles and flows through the rotor
blading. The division of the nozzles into nozzle groups is used for
power regulation. Since the mass throughput is restricted by the
nozzle cross section, the overall mass throughput and thereby the
power of the turbine can be controlled by variation of the nozzle
groups to which the working fluid is applied. The distribution of
the working fluid to the individual nozzle groups and the
individual mass throughput per nozzle group is controlled by the
control valves. A quick closing valve is provided for an emergency
shutdown which closes off the inlet and can therefore suppress the
overall flow through the turbine.
[0004] The inflow housing of a known steam turbine is shown in FIG.
2a of DE 1 915 267 A1. With the housing design basically still
manufactured today the control valves are located in what is
referred to as a valve housing or valve compartment above the
actual turbine housing. The working fluid flows in laterally
through an inlet, passes through a quick closing valve and reaches
the valve compartment from which five parallel-switched supply
lines above a control valve in each case branch off to nozzle
groups. Each valve group thus has its own supply line available to
it and a separate control valve. The respective feed lines and
valves are connected in parallel. The enclosed FIG. 1 shows a
circuit diagram of this arrangement. With current designs of such a
valve arrangement the linearly-guided valve spindles of the control
valves are each driven with an individual motor and not, as shown
in this publication, via a control bar.
[0005] In another known design of steam turbines the control valves
are arranged outside the turbine housing and linked via welded-on
pipes or pipe bends to the nozzle housing. The fresh steam flow
divided up remotely from the inflow housing is thereby guided
through the comparatively long pipes to the nozzle groups.
[0006] However both designs have the disadvantage that the inflow
housing with the external valve compartments or the pipes occupy a
great deal of space. In addition these constructions are very
costly, since very high-quality materials must be used for the cast
housings of the valves, pipes and flanges. The many diversions of
the flow in the pipes or in the supply pipes to the nozzle groups
inevitably lead to significant energy losses. In addition the
control valves described in DE 1 915 267, through which the flow is
axial, also demand high setting forces.
SUMMARY OF INVENTION
[0007] In respect of this prior art the present invention is based
on the object of developing a turbine of the type described at the
outset so that its inflow housing is as compact a design as
possible, and that the flow losses caused by long lines are
reduced. This object is achieved first of all by the control valves
being functionally divided into a primary control valve and at
least one secondary control valve. Furthermore the inlet is to be
connected to the first nozzle group via the inlet line, whereby the
inlet line is to be guided through the primary control valve such
that the flow of the working fluid along the inlet line is able to
be controlled by means of the secondary control valve. In
accordance with the invention the secondary control valve connects
the first nozzle group to the second nozzle group such that the
flow of the working fluid from the first nozzle group and the
second nozzle group is able to be controlled by means of the
secondary control valve. The present invention is based on the
underlying idea of no longer controlling individual nozzle groups
with control valves connected in parallel, but of connecting the
nozzle groups in series via the secondary control valves. This
measure basically allows savings to be made in pipe runs in the
inflow housing and thus to achieve a more compact construction. The
flow losses are also reduced by the savings in pipes. The valve
control of a primary control valve is decisive in the control of
turbine since this can control the entire flow of the working fluid
through the turbine. Since the first nozzle group is connected
directly to the inlet via the primary control valve and the quick
closing valve working fluid is always applied to the first nozzle
group when the primary control valve and the quick closing valve
are open. To increase the power, the subordinate nozzle groups are
successively switched in by the secondary control valves.
[0008] A preferred development of the invention makes provision for
at least three nozzle groups connected in series to be provided in
the inflow housing, so that at least two secondary control valves
are necessary that connect the first nozzle group to the second or
the second nozzle group to the third. To enable the power to be
controlled in even smaller steps, it is also recommended that an
additional fourth or fifth nozzle group be provided; the number of
secondary control valves necessary would consequently increase to
three or four.
[0009] As already mentioned the entire flow of the working fluid
flows to the primary control valve. To keep the actuation forces
low and to allow a soft start-up of the turbine, it is recommended
that this valve being equipped with a pilot valve.
[0010] The starting up of such a turbine is preferably undertaken
by the following steps: With the turbine at rest the quick closing
valve is initially opened which causes the pressure of the working
fluid to build up as far as the valve seat of the primary control
valve. The first nozzle group is activated directly by the primary
control valve. With the aid of a small pilot valve on the primary
control valve the turbine is initiated and brought up to its
operating speed. After the machine has accepted a load and the
first nozzle group has been fully activated, the main control valve
is started and thus releases the entire cross-section for the
overall mass flow of the working fluid. Since the mass throughput
is capped by the valve cross sections of the first group, the power
of the turbine remains constant on reaching the maximum mass
throughput. If the power of the turbine is to be increased further,
the first secondary control valve is opened so that the flow now
also reaches the second nozzle group. This increases the mass
throughput. Provided the turbine has available to it further
downstream nozzle groups, these will be switched-in later by
opening the respective secondary control valves.
[0011] The inventive circuit of the individual nozzle groups allows
the shut-off facilities of the secondary control valves to be
arranged directly between the nozzle groups extending in the shape
of a ring sector around the rotor, i.e. at the same radius as the
nozzle groups. The flow paths in the inflow housing are further
shortened in this way.
[0012] The space occupied by the inflow housing can be
significantly reduced in this design by the axes of actuation of
the secondary control valves being arranged radially to the axis of
rotation of the rotor. The actuation path of the shut-off
facilities is then not actually located tangentially to the
diameter of the nozzle groups, but radially. The necessary external
diameter of the inflow housing is reduced in this way.
[0013] Preferably in this embodiment the shut-off facilities of the
secondary control valves are designed as rotationally-switchable
control flaps so that the actuation axis involved is an axis of
rotation. The rotationally-switched shut-off facilities occupy less
space than the linearly-switched shut-off facilities, require lower
actuation forces and do not have to be completely sealed. The use
of rotationally-switched, not completely sealed shut-off facilities
is also possible since no quick closing function is required for
the secondary control valves. This quick closing function is
performed by the quick closing valve and the downstream primary
control valve. Preferably the inflow housing of the inventive
turbine is an essentially annular design and is subdivided into at
least two housing halves, with the inlet line being an integral
component of a housing half. The advantage of this embodiment is
that the line of the working fluid can be welded on without a
flange connection, that only one entry into the turbine housing
must be sealed off with the piston ring and that all components
warm up well during the start of phase. With a large volume of
steam the two housing halves can each be provided with an
integrated inlet in order to double the normal width of the inlet
steam connection overall.
[0014] The present invention is preferably employed in the area of
axial designs of steam turbine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention will now be explained in greater
detail with reference to an exemplary embodiment. The figures
show:
[0016] FIG. 1: a conventional valve circuit (prior art);
[0017] FIG. 2: an inventive valve circuit;
[0018] FIG. 3: an inflow housing in a part-exploded perspective
view;
[0019] FIG. 4: an inflow of housing in a part-exploded
rearview;
[0020] FIG. 5: a section through the inflow housing;
[0021] FIG. 6: an inflow housing with two inlets.
DETAILED DESCRIPTION OF INVENTION
[0022] FIG. 1 shows a schematic diagram of the last circuit of a
conventional steam turbine, as is known from the publication
mentioned at the start. The housing of the turbine comprises an
inflow housing 1 in which the rotor not shown in the diagram is
supported to allow rotation. The rotor has working fluid applied to
it via four nozzle groups 21, 22, 23, 24 which extend in the shape
of an annular sector on a common diameter D around the rotor.
[0023] The working medium--steam in the case of a steam
turbine--flows through an inlet 3 into the inflow housing 1.
Directly behind the inlet 3 is arranged a quick closing valve 4
through which the inlet 3 can be rapidly closed in an emergency.
Behind the quick closing valve 4, the flow fans out in four supply
lines 51, 52, 53, 54 which connect the inlet 3 with the nozzle
groups 21, 22, 23, 24 in each case. The flow of the working fluid
through the supply lines 51, 52, 53, 54 is controlled by respective
control valves 61, 62, 63, 64. The nozzle groups 21 through 24 are
consequently connected in parallel via their respective supply
lines 51 through 54 and the associated control valves 61 through
64.
[0024] The inventive circuit is shown in FIG. 2. Here the inlet 3
(fresh steam connection) able to be closed off via the quick
closing valve 4 is connected via an inlet line 7 directly and
exclusively to the first nozzle group 21. The inlet line 7 is
routed through the primary control valve 8 which controls the
overall flow through the turbine. The primary control valve 8 is
advantageously equipped with a pilot valve which can be realized
for example by a pilot valve connected in parallel (not shown in
the diagram). Quick closing valve 4, primary control valve 8 and
first nozzle group 21 are thus connected in series via the inlet
line 7. The series circuit continues into the second to 22, third
23 and fourth nozzle group 24. The second nozzle group 22 is
connected to the first nozzle group 21 exclusively via a first
secondary control valve 91. The connection of the second nozzle
group 22 to the third nozzle group 23 is made in the same way via a
second secondary control valve 92, the connection into the fourth
nozzle group 24 is made accordingly via a third secondary control
valve 93.
[0025] The shut-off facilities 10 of the secondary control valves
91, 92, 93 are located on the same diameter D as the nozzle groups
21, 22, 23, 24. In this way an especially compact design of the
inflow housing 1 is achieved. The axes of actuation 11 of the
secondary control valves extend radially to the axis of rotation of
the rotor, i.e. the center of the housing. Through these measures
the setting motors 12 of the actuation facilities can be arranged
outside the inflow housing 1.
[0026] Concrete proposed layouts of this design can be seen in
FIGS. 3 through 5. The secondary control valves 91, 92, 93 are to
be activated rotationally here so that the shut-off facilities 10
are rotary flaps. The setting motors 12 are placed on the inflow
housing 1, i.e. in the pressure-free area. Only the axis of
actuation left in the housing 11 must be sealed, which is easy to
do with axes of rotation.
[0027] The inflow housing 1 itself is therefore essentially annular
and far more compact than in the prior art since it merely
accommodates the nozzle groups 21, 22, 23 and the shut-off
facilities 10.
[0028] The inflow housing 1 is cast and divided up into and upper
housing half 1a and a lower housing half 1b, with the inlet line 7
being an integral component of the lower housing half 1b. Primary
control valve 8 and quick closing valve 4 are arranged outside the
housing 1. Thus only one steam feed into the turbine housing is to
be sealed with piston rings. The steam line can thus be welded on
without a flange connection.
[0029] With a very large volume of steam it is likewise possible to
provide the inflow housing with two inlet lines, in order to double
the nominal width of the inflowing steam connection in this way.
Two primary control valves and two quick closing valves are then
accordingly also required, one for each inlet. FIG. 6 shows and
inflow housing with two integrated inlet lines 7.
[0030] As well as the compact dimensions and the lower flow losses,
a particular advantage of the construction shown lies in the lower
setting forces of the valves. Thus especially the inner control
flaps only need small setting forces and especially no quick
closing facility since they are connected in series with the
primary control valve 8 and the quick closing valve 4. In addition
the inner control flaps can be removed and replaced without opening
the turbine housing.
* * * * *