FORM 2
The Patents Act, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE
SPECIFICATION
(See section 10 and rule 13)
I. TITLE OF THE INVENTION
COMBINED CYCLE POWER GENERATING DEVICE
2. APPLICANT (S)
(a) NAME
(b) NATIONALITY
(c) ADDRESS
: MlTSUBlSHl HEAVY INDUSTRIES, LTD.
: A company incorporated in Japan
: 16-5, Konan 2-chome, Minato-ku, Tokyo 1088215
Japan
5. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention
and the manner in which it is to be performed.

BACKGROUND OF THE INVENTION

Field of the Invention
The present invention relates to a combined cycle
power generating device in which the steam
discharged from a high-pressure chamber of a steam
turbine is reheated by the exhaust heat of the
exhaust gas emitted from a gas turbine so that the
reheated steam is supplied t o an
intermediate-pressure chamber of the steam turbine
and used to promote the drive of the steam turbine;
the present invention especially relates to a
combined cycle power generating device in which the
turbine rotor in the intermediate-pressure chamber
can be effectively cooled.

Background of the Invention
The combined cycle power generating device in which
at least one gas turbine and at least one steam
turbine are combined is previously known. Since the
. .
combined cycle power generating device in which the
gas turbine and the steam turbine are combined
efficiently generates electric power in a manner
that the exhaust heat of the gas turbine promotes
the power generation of the steam turbine, the fuel
consumption and the CO2generation are kept low;
accordingly, the demand for the combined power
generating device is expanding in recent years.

In the combined cycle power generating device, the
exhaust heat of the gas turbine reheats the steam
discharged from the high-pressure chamber of the
steam turbine and the reheated steam (the reheat
steam) is supplied to the intermediate- pressure
chamber so that the reheat steam promotes the power
generation of the steam turbine.
Further, in the combined cycle power generating
device in which the gas turbine and the steam turbine
are combined, the temperature of the main steam
supplied to the high-pressure turbine of the steam
turbine system is almost the same as the temperature
o f the reheat steam supplied to the
intermediate-pressure turbine of the steam turbine
system; however, the diameter of the blade in the
intermediate-pressure turbine is greater than the
diameter of the blade in the high-pressure turbine
so that the centrifugal force acting on the blade
in t h e intermediate-pressure turbineis s t r o n g e r
than the centrifugal force acting on the blade in
in the high-pressure turbine, when the steam turbine
is operated and the rotor is rotated. Thus, with
regard to the creep strength of the turbine rotor
and the blade root especially in the periphery of
the steam inlet part, a difficulty to be settled
arises. Hence, it becomes necessary to cool the
turbine rotor in the intermediate-pressure turbine
of the combined cycle power generating device.
Fig. 4 illustrates the cooling method regarding the
turbine rotor in the intermediate-pressure turbine
of the conventional combined cycle power generating
device; thereby, Fig. 4 shows the periphery of the
steam inlet of the high-pressure turbine as well as
the periphery of the steam inlet of the
intermediate-pressure turbine regarding the steam
turbine in the combined cycle power generating
device.
The steam turbine system 03 is provided with the
intermediate-pressure turbine 2 and the
high-pressure turbine 4. The intermediate-pressure
turbine 2 is provided with a plurality of stator
cascades. A plurality of stator blades 24a forms the
first stage stator cascade; a plurality of stator
blades 24b forms the second stage stator cascade;
a plurality of stator blades 24c forms the third
stage stator cascade, . . . . , and so on. Hereby, the
intermediate-pressure turbine 2 is further
provided with an intermediate- pressure turbine
casing 22 that supports the roots 23a and tips 23b
of the stator blades 24a regarding the first stage
stator cascade; in addition, the
intermediate-pressure turbine casing 22 supports
the roots 23a of the stator blades 24b, 24c, . . . .
regarding the second stage stator cascade and the
following stage stator cascades. The
intermediate-pressure turbine 2 is further
provided with a plurality of rotor cascades. A
plurality of rotor blades 26a forms the first stage
rotor cascade; a plurality of rotor blades 26b forms
the second stage rotor cascade; a plurality of rotor
blades 26c forms the third stage rotor cascade, ....,
and so on.
On the other hand, the high-pressure turbine
4 is provided with a plurality of stator cascades.
A plurality of stator blades 44a forms the first
stage stator cascade; a plurality of stator blades
44b forms the second stage stator cascade; a
plurality of stator blades 44c forms the third stage
stator cascade, . . . . , and so on. Hereby, the
high-pressure turbine 4 is further provided with a
high-pressure turbine casing 42 that supports the
roots 43a and tips 43b of the stator blades 44a
regarding the first stage stator cascade; in
addition, the high-pressure turbine casing 42
supports the roots 43a of the stator blades 44b,
44c, -... regarding the second stage stator cascade
and the following stage stator cascades. The
high-pressure turbine 4 is further provided with a
plurality of rotor cascades. A plurality of rotor
blades 46a forms the first stage rotor cascade; a
plurality of rotor blades 46b forms the second stage
rotor cascade; a plurality of rotor blades 26c forms
the third stage rotor cascade, .... , and so on.
Further, a reheat steam inlet 3 is provided so that
the reheat steam is supplied to the
intermediate-pressure turbine 2 through the inlet
3; in addition, a main steam inlet 5 is provided so
that the main steam is supplied to the high-pressure
turbine 4 through the inlet 5. The steam flow
direction regarding the reheat steam inlet'3 of the
intermediate-pressure turbine 2 is directed toward
the counter-direction of the steam flow direction
regarding the main steam inlet 5 of the
high-pressure turbine 4. Further, between the
intermediate-pressure turbine 2 and the
high-pressure turbine 4, an intermediate-pressure
dummy part 6 is provided so as to cancel the thrust
force developed in the intermediate-pressure
turbine 2, and a high-pressure dummy part 7 is also
provided so as to cancel the thrust force developed
in the high-pressure turbine 4. Further, a space 8
is provided between the intermediate-pressure
dummy part 6 and the high-pressure dummy part 7.
As depicted in Fig. 4, in the steam turbine system
03, a part of the steam between the stator blades
44a of the first stator cascade in the high-pressure
turbine 4 and the rotor blades 44b of the first rotor

cascade in the high-pressure turbine 4 is bled as
the cooling steam to be supplied to the
intermediate-pressure chamber 4 via the
high-pressure dummy part 7 and the
intermediate-pressure dummy part 6, the part of the
steam as the cooling steam being depressurized after
passing through the stator blades 44a of the first
stator cascade; thus, the turbine rotor 28 in the
intermediate-pressure turbine 2 is cooled by the
cooling steam. Incidentally, in Fig. 4, the arrow
line of the black thick line marked with the symbol
C shows the flow of the cooling steam; a part of the
cooling steam is used for cooling the turbine rotor
28, and another part of the cooling steammerges with
the steam discharged from the high-pressure turbine
4 so that the confluence steam is re-heated by a
re-heater (not shown) and forms a part of reheat
steam. . .
On the other hand, with the progress of the
technology in increasing the combustion gas
temperature in the field of gas turbines in recent
years, the temperature of the main steam that is
supplied to the high-pressure turbine as well as the
temperature of the reheat steam that is re-heated
by the exhaust heat and supplied to the
intermediate-pressure turbine has been increased.
Further, in order to increase the cycle efficiency

of the combined cycle power generating device, the
turbine reaction blading has been recently studied
and developed; hence, in comparison with the case
where conventional impulse blading is used, the
temperature of the reheat steam is inclined to be
enhanced. Accordingly, in the conventional
technology as depicted in Fig. 4, there may be a
difficulty that the turbine rotor 28 in the
intermediate-pressure turbine 2 is insufficiently
cooled.
Further, in relation to the combined cycle power
generating device, Patent Reference 1 discloses
another technology by which the turbine rotor in the
intermediate-pressure turbine can be cooled;
namely, Patent Reference 1 discloses a technology
regarding a combined cycle power generating device
provided with:
a gas turbine plant including a compressor, a
combustor and a gas turbine;
a steam turbine plant including a high-pressure
turbine, an intermediate-pressure turbine and a
low-pressure turbine; and,
a heat recovery steam generator producing the
high-pressure steam driving the high-pressure
turbine, the intermediate-pressure steam driving
the intermediate-pressure turbine, and the
low-pressure steam driving the low-pressure

turbine, by use of the exhaust gas discharged from
the gas turbine,
wherein
a part of the intermediate-pressure steam
produced by the heat recovery steam generator is
used for cooling the transition pieces of the
combustor, the temperature of the part of the steam
being higher than the saturation temperature
regarding the intermediate-pressure drum in the
. .
heat recovery steam generator,
the steam that is heated-up after cooling the
transition pieces is recovered and supplied to the
intermediate-pressure turbine,
the blades of the gas turbine are cooled by use
of the steam bled from the high-pressure turbine;
the steam that is heated-up after cooling the
blades of the gas turbine is recovered and supplied
to a middle location of the re-heater in the heat
recovery steam generator.
[References]
[Patent References]
Patent Reference 1: J P 3 5 0 0 0 2 0
SUMMARY OF THE INVENTION
Subjects to be solved
In the technology disclosed by Patent Reference 1
as described above, a part o f the

intermediate-pressure steam that is produced by the
intermediate-pressure drum in the heat recovery
steam generator is used for cooling the transition
pieces of the combustor; thereby, the temperature
of the steam is higher than the saturation
temperature regarding the intermediate-pressure
drum in the heat recovery steam generator. Further,
according to the technology of Patent Reference 1,
after the steam that is produced by the
intermediate-pressure drum has cooled the
transition pieces of the combustor, the steam (the
transition piece cooling steam) can cool the turbirie
rotor in the intermediate-pressure turbine.
However, the transition piece cooling steam is
supplied to the intermediate-pressure turbine,
after the transition piece cooling steam is mixed
with the reheat steam supplied to the
intermediate-pressure turbine. In view of the
reheat steam, the transition piece cooling steam is
mixed with the reheat steam before the reheat steam
enters the intermediate-pressure turbine.
Accordingly, the transition piece cooling steam
cools not only the turbine rotor but also the reheat
steam. In this way, there arises a difficulty that
the thermal efficiency regarding the whole combined
power generating device is reduced.
In view of the difficulties in the conventional
technology, the present invention aims atprovidinj
a combined cycle power generating device in which
the turbine rotor in the intermediate-pressure
turbine can be efficiently cooled without
deteriorating the thermal efficiency regarding the
whole combined power generating device.
Means to solve the Subjects
In order to achieve the objectives, the present
invention discloses a combined cycle power
generating device in which exhaust heat of a gas
turbine reheats steam which is discharged from a
high pressure chamber of a steam turbine so that the . .
reheated steam is supplied t o an
intermediate-pressure chamber, thereby driving the
steam turbine, wherein
cooling steam that has cooled the gas turbine
is supplied to the intermediate-pressure chamber
via a cooling steam inlet different from an inlet
for reheat steam that is reheated by the exhaust heat
of the gas turbine, so that the cooling steam is used
for cooling purpose,
the temperature of the cooling steam being
higher than the temperature of the steam discharged
from the high pressure chamber.
According to the above, the cooling steam is
supplied to the intermediate- pressure chamber via

the cooling steam inlet different from the inlet of
the reheat steam; thus, the cooling steam can be
supplied to the intermediate- pressure chamber,
without cooling the reheat steam.
Further, the temperature of the cooling steam
that has cooled the gas turbine is lower than the
temperature of the reheat steam; thus, when the
cooling steam is supplied to the intermediate pressure
chamber, the turbine rotor in the
intermediate-pressure chamber can be efficiently
cooled.
Incidentally, the temperature of the steam at
the outlet side of the high-pressure chamber is
excessively lower than the temperature of the reheat
steam; therefore, if the steam at the outlet side
of the high-pressure chamber is used as the cooling
steam, then the temperature control regarding the
intermediate-pressure chamber becomes difficult,
because of the great difference between the
temperature of the reheat steam and the temperature
of the steam at the outlet side of the high-pressure
chamber. Hence, it becomes necessary that the
temperature of the cooling steam (to be used for
cooling the intermediate-pressure chamber) be
higher than the temperature of the steam at the
outlet side of the high-pressure chamber.
..
A preferable embodiment of the present invention is
the combined cycle power generating device, the
intermediate-pressure chamber including, but is
not limited to:
an intermediate pressure casing for supporting
. .
roots and tips of stator blades of a first stage
stator cascade that is placed immediately behind the
reheat steaminlet, as well as roots of stator blades
of a second stage stator cascade and the following
stage stator cascades; and
an intermediate pressure turbine rotor having
a plurality of rotor cascades, the intermediate
pressure turbine rotor being housed in the
intermediate pressure casing,
wherein the cooling steam inlet is communicated
to a space between the first stage stacor cascade
and a first stage rotor cascade, via a gap between
the intermediate pressure turbine rotor and the
intermediate pressure casingata location where the
intermediate pressure casing supports the stator
blades of the first staqe stator cascade.
According to the above, after the reheat steam
has passed through the first stage stator cascade
and the temperature of the reheat steam is reduced
to a level of the temperature of the above-described
cooling steam, the reheat steam enters the
intermediate-pressure chamber; then, the cooling
steam enters the intermediate-pressure chamber.
Hence, the reheat steam can be supplied to the
intermediate-pressure chamber, without being
cooled by the cooling steam. Accordingly, the reheat
steam can further efficiently produce mechanical
work in the intermediate-pressure chamber.
Another preferable embodiment of the present
invention is the combined cycle Power generating
device, wherein
the pressure of the cooling steam is higher than
the pressure of the reheat steanl;
a dummy part is provided between the
intermediate pressure ~y, amb?~ - did - L ~ ? ~ ~
high-pressure chamber so as topartitionbetweenthe
chambers; and,
the cooling steam inlet is communicated with
the dummy part.
According to the above, the cooling steam also
cools the dummy part. Thus, the cooled area can be ..
enlarged.
Another preferable embodiment of the Present
invention is the combined cycle Power generating
device, wherein the cooling steam is a transition
piece cooling steam that has C O O Z ~ ~ a combustor of
the gas turbine.
In a conventional way, s i n ~ e the transition
piece cooling steam is directly mixed with the
reheat steam so as to be treated in the following
cycle process, the transition piece cooling steam
cools the reheat steam so that the thermal
efficiency is reduced. According to the above
embodiment, however, the transition piece cooling
steam is used as the cooling the steam as described
above; thus, it becomes unnecessary to mix the
transition piece cooling steam with the reheat steam.
Therefore, the deterioration of the thermal
efficiency can be prevented, the deterioration
being attributable to the temperature drop of the
reheat steam mixed with the transition piece cooling
steam
Effects of the Invention
According to the present invention, a combined cycle
power generating device can be realized; thereby,
the turbine rotor in the intermediate-pressure
turbine can be efficiently cooled without
deteriorating the thermal efficiency regarding the
L
whole combined power generating device.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows the diagram regarding the system
outline of the combined cycle power generating
device according to a first mode of the present
invention;
Fig. 2 explains the cooling regarding the
turbine rotor in the intermediate-pressure turbine
according to the first mode of the present
invention;
Fig. 3 explains the cooling regarding the
turbine rotor in the intermediate-pressure turbine
according to a second mode of the present invention;
Fig. 4 explains the cooling regarding the
turbine rotor in the intermediate-pressure turbine
according to a conventional technology. ..
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereafter, the present invention will be described
in detail with reference to the modes or embodiments
shown in the figures. However, the dimensions,
materials, shape, the relative placement and so on
of a component described in these modes or
embodiments shall not be construed as limiting the
scope of the invention thereto, unless especially
specific mention is made.
(First Mode)
Fig. 1 shows the diagram regarding the sysg
outline of the combined cycle power generating
device according to a first mode of the present
invention.
The combined cycle power generating device 1
includes a gas turbine (system) 01, a heat recovery
steam generator 02, and a steam turbine system 03
that includes-a high-pressure turbine 4, an
intermediate-pressure turbine and a low-pressure
turbine 10.
As shown in Fig. 1, the gas turbine system 01
includes-a compressor 12, a combustor 13 and a gas
turbine 11; the compressor 12 inhales the
atmospheric air and compresses the air to a
predetermined pressure level; in the combustor 13,
the air compressed by the compressor 12 and fuel are
mixed and burnt so that the temperature of the^
combustion gas reaches a prescribed temperature at
the turbine inlet (combustion gas inlet). After
having produced mechanical work in the combustor13,
the combustion gas is discharged as the exhaust gas
from the gas turbine, and supplied toward the heat
recovery steam generator 02 via an exhaust gas duct
9.
Further, the heat recovery steam generator 02
includes-a low-pressure drum 14, an
intermediate-pressure drum 15 and a high-pressure
drum 16; in each drum, superheated steam is
generated. The steam generated in the high-pressure
drum 16 as the main steam is supplied to the
high-pressure turbine 4 through a high-pressure
steam pipe 17, and expands so as to produce
mechanical work in the high-pressure turbine 4. The

steam discharged from the steam outlet of the
high-pressure turbine 4 is supplied to a re-heater
18RH so as to be reheated therein: the reheated steam
as the reheat steam is supplied to the
intermediate-pressure turbine 2.
Further, the steam generated in the
intermediate-pressure drum 15 is supplied to the
transition pieces of the combustor 13 through a
cooling steam pipe 18, and cools the transition
pieces; the steam that has cooled the transition
pieces of the combustor 13 and is heated-up by the
heat exchange to a temperature level higher than the
temperature level at the steam outlet the
high-pressure turbine 4; and, the heated-up steam
is fed to the intermediate-pressure turbine 2
through a cooling steam recovery pipe 19, as
described later.
Further, the reheat steam supplied to the
intermediate-pressure turbine 2 expands so as to
produce mechanical work in the
intermediate-pressure turbine 2; then, the steam
having produced mechanical work therein is
discharged out of the intermediate-pressure
~ . .
turbine 2, and merges with the steam that is
generated in the low-pressure drum 14 and fed
through a low-pressure steam pipe 2 0 . And, the
confiuerce of the steam is fed to the steam inlet
of the low-pressure turbine 10. . . -
the supplied to the steam inlet of the
low-pre5sure turbine 10 expands SO as to produce
mechanical work in the low-pressure turbine 10, the
work being added to the power produced
by the generator (not shown) ; the steam having
produced mechanical work in the low-pressure
turbine 10 is fed to a condenser (not shown) So as
to be condensed into water. Further, the cuidensed
water is pressurized to a prescribed pressure by a
pressure pump, and fed to the heat recovery steam
generator 02 via a 'feed water pipe.
In the next place, in relation to the combined cycle
power generating device 1 as shown in Fig. 1, the
cooling regarding the intermediate-pressure
turbine 2 is explained. F i q . 2. explains the cooling
regardip9 the turbine rotor in the
intermediate-pressure turbine according to the
first mode of the present invention; in addition,
Fig.2 shows the periphery of the steam inlet of the
high-pressure turbine as well as the periphery of
the steam inlet of the intermediate-pressure
turbine regarding the steam turbine system.
As already described based on fig . 1, the steam
turbine system 03 includes a high-pressure turbine
4, an intermediate-pressure turbine 2 and a
low-pressure turbine 10
The intermediate-pressure turbine 2 includes
/ ,. .
a plurality of stator cascades. A plurality of
stator blades 24a forms the first stage stator
cascade; a plurality of stator blades 24b forms the
second stage stator cascade; a plurality of stator
blades 24c forms the third stage stator
cascade, . . . . , and so on. Hereby, the
intermediate-pressure turbine 2 'further includes
an intermediate- pressure turbipe casing 22 that
supports the roots 23a and tips 23b of the stator
blades 24a regarding the first stagestator cascade;
in addition, the intermediate-pressure turbine
casing 22 supports the roots 23a of the stator blades
24b, 24c, "" regarding the second stage s t a t ~ r
cascade and the following stage stator cascades. The
intermediate-pressure turbine 2 further includes a
plurality of rotor cascades. A plurality of rotor
blades 26a forms the first stage rotor cascade; a
plurality of rotor blades 26b forms the second stage
rotor cascade; a plurality of rotor blades 26c forms
the third stage rotor cascade, * " ' , and so on.
On the other hand, the high-pressure turbine
4 includes a plurality of stator cascades. A
plurality of stator blades 44a forms the first stage

stator cascade; a plurality of stator blades 44b
forms the second stage stator cascade; a plurality
of stator blades 44c forms the third stage stator
cascade, " " , and so on. Hereby, the high-pressure
turbine 4 further includes a high-pressure turbine
casing 42 that supports the roots 43a and tips 43b
of the stator blades 44a regarding the first stage
stator cascade; in addition, the high-pressure
turbine casing 42 supports the roots 43a of the
stator blades 44b, 44c, regarding the second
stage stator cascade and the following stage stator
cascades. The high-pressure turbine 4 further
includes a plurality of rotor cascades. A plurality
of rotor blades 46a forms the first stage rotor
cascade; a plurality of rotor blades 46b forms the
second stage rotor cascade; a plurality of rotor
blades 26c forms the third stage rotor cascade, -...,
and so on.
Further, a reheat steam inlet 3 is provided so thst
the reheat steam is supplied to the
intermediate-pressure turbine 2 through the inlet
3; in addition, a main steam inlet 5 is provided so
that the main steam is supplied to the high-pressure
turbine 4 through the inlet 5. The steam flow
direction regarding the reheat steam inlet 3 of the
intermediate-pressure turbine 2 is directed toward
the counter-direction of the steam flow direction
regarding the main steam inlet 5 of the
high-pressure turbine 4. Further, between the
intermediate-pressure turbine 2 and the high pressure
turbine 4, an intermediate-pressure dummy
part 6 is provided so as to cancel the thrust force
developed in the intermediate-pressure turbine 2,
and a high-pressure dummy part 7 is also provided
so as to cancel the thrust force developed in the
high-pressure turbine 4. Further, a space 8 ?s.
provided between the intermediate-pressure dummy
part 6 and the high-pressure dummy part 7.
In the steam turbine system 03 as depicted in Fig.
2, a communicating passage 31 is provided so as to
communicate allocation between the stator blades 44a
of the first stator cascade in the high-pressure
turbine 4 and the rotor blades 44b of the first rotor
cascade in the high-pressure turbine 4 to a location
between the stator blades 24a of the first stator
cascade in the intermediate-pressure turbine 2 and
the rotor blades 26a of the first rotor cascade in . . .
the intermediate-pressure turbine 2. In this manner,
a part of the steam between the stator blades 44.3
of the first stator cascade in the high-pressure
turbine 4 and the rotor blades 44b of the first rotor
cascade in the high-pressure turbine 4 is bled as
the cooling steam for cooling the turbine rotor 28
in the intermediate-pressure turbine 2, the part of
the steam as the cooling steam being depressurized
after passing through the stator blades 44a of the
first stator cascade. Hereby, the bled steam is
supplied to the location between the stator blades
24a of the first stator cascade in the
intermediate-pressure turbine 2 and the rotor
blades 26a of the first rotor cascade in the
intermediate-pressure turbine 2, via the
communicating passage 31, so as to cool the turbine
rotor 28 in the intermediate-pressure turbine 2.
Incidentally, in Fig. 2, the arrow line of the black thick
line marked with the symbol B shows the flow
of the cooling steam from the high-pressure turbine
4. Further, a part of the cooling steam is used for
cooling the turbine rotor 2 8 in the
intermediate-pressure turbine 2; another part of
the cooling steam merges with the steam discharged
from the high-pressure turbine 4, via a space 8 and
a pipe line (a steam passage) 8' that merges with
a steam pipe line depicted with a symbol a in Fig.
1, the passage 8' merging with the steam flow that
is discharged out of from the high-pressure turbine
4. And the confluence steam is reheated so as to form
I . '
a part of the reheat steam.
6
Further, a specific configuration of the present
invention is that the cooling steam (hereafter also
called the transition piece cooling steam) that has
been heated-up by cooling he transition pieces of
the combustor613 streams through the cooling steam
recovery pipe 19, and the cooling steam recovery
pipe 19 merges with the communicating passage 31,
at the location between the intermediate-pressure
dummy part 6 and the intermediate-pressure turbine
2. In this way, the transition piece cooling steam
that has cooled the transition pieces of the
combustor 13 in the gas turbine 01 is supplied to
the location between the stator blades 24a of the
first stator cascade and the rotor blades 26a of the
first rotator cascade in the intermediate-pressure
turbine 2; thus, the transition piece cooling steam'
cools the turbine rotor 28in the
intermediate-pressure turbine 2. Incidentally, in
Fig. 2, the arrow line of the black thick line marked
with the symbol A shows the flow of the transition
piece cooling steam.
According to the first mode of the present invention,
in addition to the cooling steam streaming from the
high-pressure turbine 4 t o the
intermediate-pressure turbine 2 as depicted by the
steam flow marked with the symbol B in Fig. 2,'the
transition piece cooling steam cools the turbine
rotor 28 in the intermediate-pressure turbine 2 as
depicted by the steam flow marked with the symbol
Ain Fig. 2. The temperature of the transition piece

cooling steam is lower than the temperature of the
cooling steam streaming through the flow line marked ._. .
with the symbol Bin Fig. 2; accordingly, the cooling
effect regarding the turbine rotor 28 in the
intermediate-pressure turbine 2 can be enhanced by
use of the transition piece cooling steam.
Incidentally, on the other hand, it can be
considered that the steam on the outlet side of the
high-pressure turbine 4 is made use of so as to cool
the turbine rotor 28, in view of the steam process
regarding the combined cycle power generating
device; thereby, the temperature of the steamon the
outlet side of the high-pressure turbine 4 is lower
than the temperature of the transition piece cooling
steam. However, the temperature of the steam on the outlet
side of the high-pressure turbine 4 is
excessively lower than the temperature of the
transition piece cooling steam and the cooling
effect is surplus; hence, when the steam on the
outlet side of the high-pressure turbine is used for
cooling the turbine rotor 28 and the intermediate pressure
turbine 2, the temperature control becomes
difficult. Therefore, it is preferable to use the
steam of which the temperature is higher than the
temperature of the steam on the outlet side of the
high-pressure turbine 4 and lower than the
temperature of the steam streaming through the flow . ~. -
line marked with the symbol B in Fig. 2; and, the

transition piece cooling steam satisfies this
preferable condition, and is optimal as the cooling
steam that cools the part in question.
Further, toward the location between the stator
blades 24a of the first stator cascade in the
intermediate-pressure turbine 2 and the rotor
blades 26a of the first rotor cascade in the
intermediate-pressure turbine 2, the steam
streaming through the flow line marked with the
symbol B as well as the transition piece cooling
steam is supplied. After both the steam cools the
part in question, both the steam (confluence steam)
can be fed to the intermediate-pressure turbine 2,
via the re-heater, without reducing the temperature
of the reheat steam. . ,. .
In other words, the turbine rotor in the
intermediate-pressure turbine can be efficiently
cooled, without deteriorating the whole thermal
cycle.
(Second Mode)
Fig. 3 explains the cooling regarding the turbine
rotor in the intermediate-pressure turbine
according to a second mode of the present invention;
Fig. 3 shows the periphery of the steam inlet of the
high-pressure turbine as well as the periphery of
the steam inlet of the intermediate-pressure

turbine regarding the steam turbine in the combined
cycle power generating device.
Incidentally, the same components in Fig. 3 as
in Fig. 2 are given common numerals or symbols and,
explanation repetitions regarding the same
...
components are omitted. Further, in this second mode,
the system diagram regarding the whole combined
cycle power generating device is the same as that
in Fig. 1 of the first mode, except the steam flow
lines that appear in the space 8; thus, the drawing
and the explanation are omitted on the premise that
the explanation is given by the aid of Fig.1.
In Fig. 3, the pipe line 8' is merged with a part
b' of Fig. 1.

The pressure of the steam in the space 8 is
almost the same as the pressure of the steam at the
counter-end side of the pipe line 8'. Thus, in fig.
3, the pressure of the steam in the space 8 is almost
the same as the pressure of the steam at the inlet
side of the intermediate-pressure turbine 2, the
pressure of the steam in the space 8 being lower than
the pressure of the transition piece cooling steam.
Hence, as shown by the arrow line marked with
the symbol A' in Fig. 3 regarding the second mode,
apart of the transition piece cooling steam streams
toward the turbine rotor 2 8 in the
intermediate-pressure turbine 2 so as to cool the
turbine rotor 28; and, another part of the
transition piece cooling steam streams toward the
inlet side (the line part b in Fig. 1) of the
intermediate- pressure turbine 2 , via
intermediate-pressure dummy part 6 and the space 8,
so as to merge with the reheat steam. Thereby, as
shown by the arrow line marked with the symbol B;.
in Fig. 3, the cooling steam from the high-pressure
turbine 4 wholly streams toward the inlet side (the
line part in Fig. 1) of the intermediate- pressure
turbine 2, via the space 8 and the pipe line 8', so
as to merge with the reheat steam.
According to the above-described second mode of the
present invention, in addition to the same effect
as by the first mode, the intermediate-pressure
dummy part 6 can be also cooled by use of the
transition piece cooling steam. Thus, the cooled
area can be enlarged.

Industrial Applicability
The present disclosure can be applicable to the -
combined cycle power generating device in which the
turbine rotor in the intermediate-pressure turbine
can be efficiently cooled, without deteriorating
the whole thermal cycle.

WE CLAIM:
1. A combined cycle power generating device in
which exhaust heat of a gas turbine reheats steam
which is discharged from a high pressure chamber of
a steam turbine so that the reheated steam is
supplied to an intermediate-pressure chamber,
thereby driving the steam turbine, wherein
cooling steam that has cooled the gas turbine.
is supplied to the intermediate-pressure chamber
via a cooling steam inlet different from an inlet
for reheat steam that is reheated by the exhaust heat
of the gas turbine, so that the cooling steam is used
for cooling purpose,
the temperature of the cooling steam being
higher than the temperature of the steam discharged
from the high pressure chamber.
2. The combined cycle power generating device
according to claim 1, the intermediate pressure
chamber comprising:
an intermediate pressure casing for supporting
roots and tips of stator blades of a first stage
stator cascade that is placed immediately behind the
reheat steam inlet, as well as roots of stator blades
of a second stage stator cascade and the following
stage stator cascades; and
an intermediate pressure turbine rotor having
a plurality of rotor cascades, the intermediate
pressure turbine rotor being housed in the
intermediate pressure .casing,
wherein the cooling steam inlet is communicated
to a space between the first stage stator cascade
and a first stage rotor cascade, via a gap between
the intermediate pressure turbine rotor and the
intermediate pressure casing at a location where the
intermediate pressure casing supports the stator
blades of the first stage stator cascade.
3. The combined cycle power generating device
according to claim 1 or 2, wherein
the pressure of the cooling steam is higher than
the pressure of the reheat steam;
a dummy part is provided between the
intermediate pressure chamber and the
high-pressure chamber so as to partition between the
chambers; and,
the cooling steam inlet is communicated with
the dummy part.
4. The combined cycle power generating device
according to claim 1, 2 or 3, wherein the cooling
steam is a transition piece cooling steam that has
cooled a combustor of the gas turbine.