U.S. patent application number 12/598609 was filed with the patent office on 2010-06-03 for shaft seal for steam turbines.
Invention is credited to Edwin Gobrecht, Achim Hammann, Dirk Knudsen, Karsten Peters, Jan Walkenhorst.
Application Number | 20100133756 12/598609 |
Document ID | / |
Family ID | 39673036 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100133756 |
Kind Code |
A1 |
Gobrecht; Edwin ; et
al. |
June 3, 2010 |
Shaft seal for steam turbines
Abstract
A shaft seal for steam turbines is provided. The shaft seal
steam barrier is supplied with a slight excess pressure. In order
to avoid complex additional devices necessary for liquefying the
water vapor once again, a condensation chamber, which is sealed
from the surrounding air as well as from the steam barrier chamber
with brush seals, is provided between the steam barrier chamber and
the surrounding air. The condensation chamber is constructed in
such a manner that the heat, developing in the interior thereof, is
discharged to the outside.
Inventors: |
Gobrecht; Edwin; (Ratingen,
DE) ; Hammann; Achim; (Oberhausen, DE) ;
Knudsen; Dirk; (Gladbeck, DE) ; Peters; Karsten;
(Wesel, DE) ; Walkenhorst; Jan; (Mulheim an der
Ruhr, DE) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Family ID: |
39673036 |
Appl. No.: |
12/598609 |
Filed: |
April 22, 2008 |
PCT Filed: |
April 22, 2008 |
PCT NO: |
PCT/EP08/54868 |
371 Date: |
November 3, 2009 |
Current U.S.
Class: |
277/350 ;
277/355 |
Current CPC
Class: |
F02C 7/24 20130101; F01D
11/00 20130101; F05D 2220/31 20130101; F05D 2240/56 20130101; F16J
15/3288 20130101 |
Class at
Publication: |
277/350 ;
277/355 |
International
Class: |
F16J 15/447 20060101
F16J015/447; F16J 15/16 20060101 F16J015/16; F01D 11/04 20060101
F01D011/04; F16J 15/44 20060101 F16J015/44; F16J 15/32 20060101
F16J015/32 |
Foreign Application Data
Date |
Code |
Application Number |
May 9, 2007 |
DE |
10 2007 021 742.2 |
Claims
1.-3. (canceled)
4. A shaft seal for steam turbines, comprising: a shaft-seal
sealing chamber; a condensation chamber provided between the
sealing-steam chamber and a surrounding air; a plurality of brush
seals, wherein the shaft-seal sealing chamber is fed with a slight
overpressure, wherein the condensation chamber is sealed by the
plurality of brush seals both in relation to the surrounding air
and in relation to the sealing-steam chamber, and wherein the
condensation chamber is constructed so that the heat which develops
therein is discharged to the outside.
5. The shaft seal as claimed in claim 4, wherein the condensation
chamber is fixed with a flange and wherein an insulating layer is
arranged between the condensation chamber and steam turbine.
6. The shaft seal as claimed in claim 4, wherein the condensation
chamber is cast onto the steam turbine and is insulated in relation
to the steam turbine.
7. The shaft seal as claimed in claim 4, wherein the sealing-steam
chamber is sealed in relation to an inside of the steam turbine by
a labyrinth seal.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2008/054868, filed Apr. 22, 2008 and claims
the benefit thereof. The International Application claims the
benefits of German application No. 10 2007 021 742.2 DE filed May
9, 2007, both of the applications are incorporated by reference
herein in their entirety.
FIELD OF INVENTION
[0002] The present invention refers to a shaft seal for steam
turbines, in which the shaft-seal sealing steam is fed with a
slight overpressure.
BACKGROUND OF INVENTION
[0003] Shaft seals of steam turbines are constructed with sealing
steam. The sealing steam is fed to the shaft seal with a slight
overpressure. During operation, the sealing-steam system is
supplied with steam from the steam turbine at a suitable pressure
and temperature. When evacuating before start-up of the machine,
and at low load, the sealing steam is extracted from an auxiliary
steam system.
SUMMARY OF INVENTION
[0004] The sealing-steam system comprises a sealing-steam chamber
which is under a slight overpressure, and a leakoff-steam chamber
which is held under a slight negative pressure in relation to
atmosphere. In the leakoff-steam chamber the ingressing air and a
partial mass flow of the steam from the sealing-steam chamber mix
together. This so-called leakoff vapor is exhausted by means of a
blower. The steam which is contained herein is re-liquefied in a
condenser and fed to the water-steam system. For this, a costly
piping construction for the leakoff lines, including exhaust
blowers, valves and leakoff steam condenser, is required.
[0005] It is the object of the present invention to disclose a
shaft seal of the type referred to in the introduction, in which
complex additional devices are not necessary in order to re-liquefy
the leakoff vapor.
[0006] This object is achieved for the shaft seal which is referred
to in the introduction by a condensation chamber being provided
between the sealing-steam chamber and the surrounding air and being
sealed by brush seals both in relation to the surrounding air and
in relation to the sealing-steam chamber, wherein the condensation
chamber is constructed so that the heat which develops therein is
discharged to the outside.
[0007] As a result of the condensation directly on the turbine, the
entire piping construction for the leakoff lines, including exhaust
blower, valves and leakoff steam condenser, is dispensed with.
Appreciable savings therefore result in the case of the shaft seal
according to the invention.
[0008] Advantageous developments of the present invention result
from the dependent claims and also from the description of an
exemplary embodiment with reference to the attached drawing.
[0009] With reference to the attached drawing, the principle
construction of a current embodiment of a shaft seal, and also the
principle construction of a shaft seal according to the invention,
are shown in the following.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] In the drawing:
[0011] FIG. 1 shows the principle construction of a known shaft
seal, and
[0012] FIG. 2 shows the principle construction of a shaft seal
according to the invention.
DETAILED DESCRIPTION OF INVENTION
[0013] In FIG. 1, in which the prior art is shown, the turbine
casing is identified by 1 and the shaft identified by 2. The shaft
seal which is shown here has a sealing-steam chamber 3 and a
leakoff-steam chamber 4. Seals, for example labyrinth seals, are
located between the leakoff-steam chamber 4 and the surrounding air
5, and also between the leakoff-steam chamber 4 and the
sealing-steam chamber 3, and also between the sealing-steam chamber
3 and the inside of the turbine.
[0014] The leakoff lines and the valves which are associated with
them, and the leakoff-steam condenser, shall not be dealt with in
more detail here since these are known to the person skilled in the
art and these are not essential for the actual inventive idea
either.
[0015] In FIG. 2, a shaft seal according to the present invention
is shown in principle. The turbine casing is identified by 6 and
the shaft is identified by 7. The shaft seal according to the
invention has a sealing-steam chamber 8 which is sealed in relation
to the inside of the turbine by a labyrinth seal.
[0016] A condensation chamber 11 is now located between the ambient
air 5 and the sealing-steam chamber 8 and is sealed by brush seals
9 and 10 both in relation to the surrounding air 5 and in relation
to the sealing-steam chamber 8. The condensation chamber 11 in this
case is constructed so that it discharges the heat which develops
therein to the outside, that is to say, it is not integrated into
the actual steam turbine.
[0017] By the use of modern sealing technologies, such as the use
of brush seals, only a fraction of the previous leakoff steam
volume is produced. This can then be condensed directly on the
steam turbine by means of the condensation chamber 11.
[0018] As a result of the condensation directly on the steam
turbine the entire piping construction for the leakoff lines and
also the leakoff-steam condenser, the valves and the exhaust
blower, are dispensed with.
* * * * *