Rotary kinetic fluid motors or pumps – Working fluid passage or distributing means associated with... – Plural distributing means immediately upstream of runner
Reexamination Certificate
1999-10-26
2001-10-16
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Working fluid passage or distributing means associated with...
Plural distributing means immediately upstream of runner
C415S209100, C415S209300
Reexamination Certificate
active
06302648
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a jointed stationary blade of a steam turbine and more particularly to a two stage jointed stationary blade, applicable to a high pressure or intermediate pressure steam turbine, in which an outer ring for jointing a front stage stationary blade and a rear stage stationary blade together fixedly is made in a bolt joint structure so as to be detached and disassembled easily thereby to have a reduced assembling man-hour and an enhanced maintainability.
2. Description of the Prior Art
In a high pressure or intermediate pressure steam turbine, trials are being performed using a two stage jointed stationary blade in which mutually adjacent front stage and rear stage stationary blades are fixedly jointed together.
FIG. 4
is a cross sectional view of such a two stage jointed stationary blade after it has been assembled and FIGS.
5
(
a
)-(
b
) are cross sectional views of two stationary blade structural portions before they are assembled. In particular, FIG.
5
(
a
) shows a stationary blade (front stage) portion and FIG.
5
(
b
) shows a stationary blade (rear stage) portion.
In the prior art two stage jointed stationary blade shown in
FIG. 5
, a stationary blade (front stage)
42
on an upstream side of steam flow S is constructed as in an integral structure fitted with an outer ring front portion
41
and an inner ring front portion
43
fixedly by welding. A stationary blade (rear stage)
52
is also constructed as in an integral structure fitted with an outer ring rear portion
51
and an inner ring rear portion
53
fixedly by welding. These integral stationary blades
42
,
52
are jointed together fixedly by electron beam welding at a position, indicated by numeral
70
(FIG.
4
), of the outer ring front portion
41
and the outer ring rear portion
51
, such that the two stage jointed stationary blade is an integral structure.
It is to be noted that seal fitting portions
44
,
54
are formed for fitting thereto labyrinth seals in the inner ring front portion
43
and the inner ring rear portion
53
, respectively. Also, seal fin grooves
55
,
56
are formed in the outer ring rear portion
51
, as will be described later.
In the integral structure of the stationary blade (front stage)
42
shown in FIG.
5
(
a
), the outer ring front portion
41
is fitted to an outer side of the blade via welded portions
45
,
46
and the inner ring front portion
43
is fitted to an inner side of the blade via welded portions
47
,
48
. Also, the seal fitting portion
44
for fitting thereto a labyrinth seal is worked in the inner ring front portion
43
.
In the integral structure of the stationary blade (rear stage)
52
shown in FIG.
5
(
b
), the outer ring rear portion
51
consists of portions
51
a
,
51
b
,
51
c
. The portions
51
a
,
51
b
are jointed together via welded portions
58
,
59
and the portions
51
b
,
51
c
are jointed together via welded portions
56
,
57
, and the outer ring rear portion
51
is fitted to an outer side of the blade via welded portions
57
,
59
. Also, the inner ring rear portion
53
is fitted to an inner side of the blade via welded portions
60
,
61
. The seal fitting portion
54
for fitting thereto a labyrinth seal is formed in the inner ring rear portion
53
. Furthermore, the seal fin grooves
55
,
56
are worked in the outer ring rear portion
51
. Thus, the respective integral structures of the stationary blade (front stage)
42
and the stationary blade (rear stage)
52
are jointed together by electron beam welding at the position
70
, as shown in
FIG. 4
, thereby the two stage jointed stationary blade is constructed.
In the prior art two stage jointed stationary blade as described above, the respective integral structures of the outer ring, the stationary blade and the inner ring are made by TIG (tungsten inert gas) welding or MAG (metal active gas) welding and the front stage and rear stage structural bodies thereof are jointed together by electron beam welding at the position of the outer ring front portion and rear portion, and thereby the two stage jointed stationary blade is made as an integral structure. Therefore, the front stage and rear stage portions thereof cannot be separated from each other for a repair or inspection work, which results in making the work difficult. Also, the welding work itself requires a lot of man-hours, especially the jointing of the outer ring front portion
41
and the outer ring rear portion
51
requires welding around an entire periphery of the outer ring. Thus, there is a problem that large facilities of jigs, tools, etc. for performing the welding operation are needed and the necessary man-hours is also increased.
SUMMARY OF THE INVENTION
In view of the problem in the prior art, therefore, it is an object of the present invention to provide a steam turbine jointed stationary blade in which an outer ring front portion and an outer ring rear portion are jointed together in a bolt joint structure in place of the weld structure used in the prior art so as to be able to facilitate the repair or inspection work and to reduce the man-hours required to assemble the blade structure.
In order to achieve the mentioned object, the present invention provides the following arrangement.
That is, a steam turbine jointed stationary blade comprising a front stage stationary blade structural body and a rear stage stationary blade structural body. The front stage and rear stage stationary blade structural bodies are each constructed integrally by welding such that an outer ring of a stationary blade is jointed to an outer side of the stationary blade and an inner ring of the stationary blade is jointed to an inner side of the stationary blade. The structures are jointed together by the outer rings of the front stage and rear stage stationary blade structural bodies being jointed together are jointed together by a bolt.
In the jointed stationary blade of the present invention, the front stage and rear stage stationary blade structural bodies, each being made integrally, are jointed together by the bolt, and thereby detachment and disassemble thereof becomes possible and maintenance and inspection thereof can be easily performed. In the prior art jointed stationary blade, the front stage and rear stage stationary blade structural bodies are jointed together by electron beam welding so as to be fixedly integrated. This results in difficulty with respect to the detachment and disassembly required to perform the difficult work of maintenance and inspection and, furthermore, the electron beam welding, which must be done around the entire periphery of the outer ring, requires large facilities of jigs, tools, etc. and the manhours therefor also is increased. However, in the present invention, it is only necessary to install the bolt, and thus man-hours required for the assembly work can be reduced.
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patent: 2625367 (1953-01-01), Rainbow et al.
patent: 4218180 (1980-08-01), Wikstrom
patent: 4435121 (1984-03-01), Wosika
patent: 4502838 (1985-03-01), Miller et al.
patent: 4816213 (1989-03-01), Groenendaal, Jr.
patent: 4875828 (1989-10-01), Willkop et al.
patent: 4900223 (1990-02-01), Groenendaal, Jr.
patent: 5149248 (1992-09-01), Cramer
patent: 5308227 (1994-05-01), Gros et al.
patent: 5743711 (1998-04-01), Fournier et al.
patent: 195 27 662 (1997-01-01), None
patent: 93/20334 (1993-10-01), None
Konishi Tetsu
Kuwana Toyokazu
Magoshi Ryotaro
Matsuo Asaharu
Tanaka Keizo
Look Edward K.
Mitsubishi Heavy Industries Ltd.
Nguyen Ninh
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