JP2000328904A - Steam turbine wheel chamber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a difference in the temperature of an upper casing and a lower casing small by providing a cooled air pipe that communicates with a cooled air supply system provided outside and opens to the upper casing. SOLUTION: A cooled air pipe 20 communicates with a cooled air supply system 22, a headstream, provided outside of a steam turbine. Further, it communicates with an upper casing 1 via a valve 21a disposed in the course of the pipe and opens in the upper casing 1 through its inner wall surface. The valve 21a is opened immediately after parallel-off upon the stop of the steam turbine, and cooled air is introduced from the cooled air supply system 22 through the cooled air pipe 20 and supplied to the upper casing 1 to cool it forcibly. Consequently, the temperature of the upper casing 1 is reduced, effect of natural flow from a lower casing 2 can be reduced, and temperature difference between the upper casing 1 and the lower casing 2 is reduced. Therefore, a difference in axial extension of the upper casing 1 and the lower casing 2 is made small, interference between a static portion and a rotating portion is prevented, eliminating the need to stop the operation of the forced cooling, and thus fuel cost can be saved significantly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine casing for reducing the temperature difference between upper and lower casings generated when the turbine is stopped in a steam turbine.

[0002]

2. Description of the Related Art An outline of a conventional steam turbine casing will be described with reference to FIG. FIG. 9 shows an axial cross-sectional structure of a high / medium pressure integrated turbine casing in a conventional steam turbine.

[0003] The outer casing of the steam turbine has an upper casing 1 disposed in an upper half region with respect to the horizontal flange joint surface.
And the lower casing 2, which is arranged in the lower half, is fastened with bolts and nuts (not shown) on the horizontal flange joint surface.

[0004] Reference numerals 3 and 4 denote an inner casing, 5 a nozzle chamber, 6 a blade ring for supporting the stationary blades of the high-pressure turbine 30, and 7 and 8 a blade ring for supporting the stationary blades of the medium-pressure turbine 40. Inside the vehicle compartments 3, 4, the nozzle chamber 5, the blade rings 6, 7, 8 and the rotor 19 supporting the moving blades and the like are arranged.

Reference numeral 9 denotes a main steam inlet for supplying working steam to the high-pressure turbine 30 via the nozzle chamber 5; 10 a high-pressure exhaust port connected to the exhaust chamber of the high-pressure turbine 30; 11 an opening at the position of the dummy ring; Is a high-pressure dummy bypass pipe communicating with the high-pressure exhaust port 9 to balance the thrust of the high-pressure turbine 30.

Reference numeral 12 denotes a medium pressure bleeding port, 13 denotes a high temperature reheat steam inlet which is connected to a boiler reheater (not shown) and supplies working steam to a medium pressure turbine 40, and 14 and 15 denote medium pressure exhaust ports, respectively. is there.

In the conventional steam turbine having the above-described configuration, when the predetermined operation is performed and the operation is stopped,
In the convection of the air inside the outer casing, the high temperature portion moves upward and stagnates, so that the temperature of the upper casing 1 becomes higher than the temperature of the lower casing 2.

When the temperature difference between the upper casing 1 and the lower casing 2 becomes large, the outer casing becomes convex upwardly due to the difference in axial expansion between the upper casing 1 and the lower casing 2 constituting the outer casing. There is no clearance between the stationary portions of the inner casings 3 and 4 and the rotating portion of the rotor 19, and as a result, in the worst case, contact between the stationary portion and the rotating portion occurs, which may lead to damage.

[0009]

Conventionally, the steam turbine is shut down in order to prevent the stationary portions of the inner casings 3 and 4 from contacting with the rotating portion of the rotor 19 and to prevent the risk of damage. At this time, an operation method in which the steam condition is previously lowered to lower the temperature of the entire turbine and then stopped, that is, a forced cooling stop operation has been performed.

If this forced cooling stop operation is performed, low-temperature steam continues to flow until the vertical temperature difference in the outer casing disappears, so that the metal temperature on the outer surface can be lowered. The required steam conditions are reduced, the time of low-temperature operation is prolonged, and there is a problem that fuel costs rise due to excessive consumption of fuel.

The present invention eliminates the disadvantages associated with the conventional forced cooling stop operation, reduces the temperature difference between the upper and lower compartments, and prevents contact between the stationary portion and the rotating portion. It is an object of the present invention to provide a steam turbine casing that does not require the forced cooling stop operation.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a first invention of the present invention is to provide a steam turbine outer casing having an upper casing and a lower casing, which is provided outside. And a steam turbine casing provided with a cooling air pipe communicating with the cooling air supply device and opening to the upper casing.

That is, according to the present invention, by providing a cooling air pipe opening to the upper casing, supplying cooling air from an external cooling air supply device to the upper casing, and cooling the upper casing, the lower casing is cooled. Lowering the temperature of the upper compartment, which is higher than that of the lower compartment, to reduce the temperature difference between the upper and lower compartments. Is prevented from being generated.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of cooling air pipes are provided in a plurality of paths to provide a steam turbine cabin having openings at a plurality of locations in the upper cabin.

In other words, according to the present invention, the cooling air pipe communicating from the external cooling air supply device to the upper casing and supplying the cooling air to the upper casing is, for example, provided with a plurality of paths from the source flow or in the middle. The upper compartment is cooled faster and more appropriately, and the temperature difference between the upper and lower compartments is reduced because the upper compartment is opened at a plurality of locations in the upper compartment by appropriately branching to form a plurality of routes. In addition, the difference in the axial extension between the upper casing and the lower casing is reduced, and contact between the stationary part and the rotating part is prevented.

Further, the third invention is the first or second embodiment.
In the invention, the cooling air pipe has a tip protruding into the upper vehicle compartment, and provides a steam turbine casing that is opened into the upper vehicle compartment through a number of cooling air discharge holes provided in the protruding portion.

That is, according to the present invention, the cooling air pipe communicating from the external cooling air supply device to the upper casing and supplying the cooling air to the upper casing has a tip protruding into the upper casing,
And the protruding portion is provided with a number of cooling air discharge holes, and the cooling air is supplied into the upper compartment through the cooling air discharge holes, so that the cooling air is suitably dispersed in the upper compartment by the cooling air discharge holes, By appropriately cooling the upper compartment from the inside, the temperature difference between the upper and lower compartments is reduced, and the difference in the axial expansion between the upper and lower compartments is reduced to reduce the occurrence of contact between the stationary part and the rotating part. It is to prevent.

In a fourth aspect, the first or second aspect is provided.
The invention provides a steam turbine casing in which a tip end of the cooling air pipe is opened in a wall surface of the upper passenger compartment, and a plate member against which cooling air supplied from the opening collides is disposed facing the opening. Is what you do.

That is, according to the present invention, the cooling air pipe communicating from the external cooling air supply device to the upper casing and supplying the cooling air to the upper casing is opened on the wall surface of the upper passenger compartment, and formed in the opening. Since the plate member that faces the cooling air and collides with it is arranged, the cooling air that collides with the plate member is appropriately dispersed in the upper passenger compartment by the collision energy, and the upper passenger compartment is appropriately cooled from the inside. Thus, the temperature difference between the upper and lower passenger compartments is reduced, and the difference in the axial expansion between the upper and lower passenger compartments is reduced to prevent contact between the stationary part and the rotating part.

Further, the fifth invention is directed to the first or second embodiment.
In the invention, the cooling air pipe is provided with a steam turbine casing having a tip end opened in the wall surface of the upper passenger compartment and a box type nozzle installed in the opening.

That is, according to the present invention, the cooling air pipe communicating from the external cooling air supply device to the upper passenger compartment and supplying the cooling air to the upper passenger compartment is provided with a box type nozzle at the opening of the wall surface of the upper passenger compartment. Since the cooling air is installed, the cooling air supplied through the cooling air pipe is changed in direction by a box-type nozzle and sprayed into the upper passenger compartment along the upper passenger compartment wall surface, and the upper passenger compartment is appropriately cooled from the inside. Thus, the temperature difference between the upper and lower passenger compartments is reduced, and the difference in the axial expansion between the upper and lower passenger compartments is reduced to prevent contact between the stationary part and the rotating part.

Further, according to a sixth aspect based on the first or second aspect, the cooling air pipe is obliquely introduced into the upper cabin with its tip end being upstream toward the upper cabin. An open steam turbine casing is provided.

That is, according to the present invention, the cooling air pipe which communicates from the external cooling air supply device to the upper casing and supplies the cooling air to the upper casing has a tip directed upstream toward the upper casing. Since the cooling air is introduced obliquely and opened at the inner wall surface of the upper vehicle, the cooling air supplied through the cooling air pipe is scattered into the upper vehicle room along the inner wall surface of the upper vehicle from the oblique opening, and The room is cooled appropriately from the inner wall surface to reduce the temperature difference between the upper and lower vehicle compartments, and to reduce the difference in axial expansion between the upper and lower vehicle compartments to prevent contact between the stationary and rotating parts. Is what you do.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. In order to prevent the description from being redundant, the same parts as those of the above-described conventional one are denoted by the same reference numerals in the drawings, and redundant description will be omitted as much as possible.

FIG. 1 shows an axial sectional structure of a steam turbine casing of a high-to-medium pressure integrated type in this embodiment, FIG. 2 shows an enlarged sectional view of a portion A in FIG. 1, and FIG. The state of time change of the upper and lower metal temperature and the upper and lower temperature difference of the outer casing of the vehicle is described.

Reference numeral 20 denotes a cooling air pipe, which is connected to a cooling air supply device 22 provided outside the steam turbine as a source flow, communicates with the upper casing 1 via a valve 21a provided on the way, and It passes through the inner wall surface of the compartment 1 and opens into the upper compartment 1.

As shown in FIG. 2, the cooling air pipe 20 is communicated with the upper casing 1 at a position corresponding to the exhaust chamber of the high-pressure turbine 30 in the axial direction.
At the position close to the inner wall surface, the front end is bent toward the upstream side to open into the upper casing 1.

In the present embodiment configured as above, the valve 21a is opened immediately after the steam turbine is stopped when the steam turbine is stopped, and the cooling air 23 is led from the cooling air supply device 22 through the air / air pipe 20, and It is supplied into the chamber 1 to forcibly cool the upper casing 1.

As a result, the temperature of the upper passenger compartment 1 decreases, the influence of natural convection from the lower passenger compartment 2 can be reduced, and the temperature difference between the upper passenger compartment 1 and the lower passenger compartment 2 that constitute the outer passenger compartment is reduced.

In a steam turbine that performs a WSS (Weekly Start & Stop) operation, the metal temperature of the outer casing causes the upper casing 1 and the lower casing 2 to remain open for about 50 hours immediately after the steam turbine is turned off. FIG. 3 shows the result of measuring the so-called vertical temperature difference, which is the temperature difference of the above, together with the time change.

Immediately after the steam turbine is stopped, the metal temperature of the outer casing is about 350 ° C. in both the upper casing 1 and the lower casing 2.
The conventional structure shown in FIG. 3A, that is, the structure having no cooling air pipe as in the present embodiment, has a maximum temperature difference of about 60 ° C. which is the maximum temperature difference even after 30 to 40 hours. However, when the inside of the upper casing 1 is cooled with the cooling air as in the present embodiment, the vertical temperature difference is greatly reduced to about 40 ° C. as shown in FIG. ing.

Therefore, according to the present embodiment, it is possible to prevent the outer casing from warping upward due to the difference in the axial expansion between the upper casing 1 and the lower casing 2 constituting the outer casing. The clearance between the stationary portions of the inner casings 3 and 4 and the rotating portion of the rotor 19 can be secured, and contact between the stationary portions and the rotating portion can be avoided.

In the present embodiment, FIG.
As shown in FIG. 2, the so-called vertical temperature difference between the upper casing 1 and the lower casing 2 which is a so-called vertical temperature difference is about 40 ° C. at the maximum. In this case, it is not necessary to perform a forced cooling stop operation in which the steam condition is previously reduced to lower the temperature of the entire turbine and then stopped, and as a result, the fuel cost can be largely reduced.

In this embodiment, FIGS. 1 and 2
As shown in (2), the opening position of the air pipe 20 with respect to the upper casing 1 is opened at a position corresponding to the exhaust chamber of the high-pressure turbine 30 having a high absolute temperature in the upper casing 1, so that the vertical temperature difference is suppressed. Although the opening can be effectively performed, the opening is not limited to this position, and it goes without saying that another position may be selected as long as the opening is in the upper passenger compartment 1.

The temperature of the cooling air only needs to be in a substantially normal temperature range of 10 to 30.degree.
Is not limited to being provided as a dedicated device separately and independently. For example, an appropriate air supply device provided for a boiler provided in parallel with a steam turbine can be used in combination.

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. FIG. 4 shows an axial cross-sectional structure of a high- and medium-pressure integrated steam turbine casing according to the present embodiment, and the same parts as those of the above-described conventional one and the first embodiment are the same in the drawings. And the overlapping description will be omitted as much as possible.

That is, according to the present embodiment, the cooling air pipe 20 communicating from the cooling air supply device 22 is branched into cooling air pipes 20a, 20b, and 20c. The cooling air pipe 20b is opened at a position corresponding to an intermediate stage between the high-pressure turbine 30 and the intermediate-pressure turbine 40 in the upper casing 1, and the cooling air pipe 2b is opened at a position corresponding to the exhaust chamber of the turbine 30.
0c is open at a position corresponding to the inlet chamber of the intermediate pressure turbine 40.

The cooling air pipes 20a, 20b,
The valves 20a are provided with valves 21a, 21b and 21c, respectively, so that the cooling air pipes 20a, 20b and 20c can be individually opened and closed independently. It is configured as follows.

In the present embodiment configured as described above, the valves 21a, 21b, 21c of the cooling air pipes 20a, 20b, 20c are selectively opened immediately after disconnection when the steam turbine is stopped, and set to the open position. The cooling air 23 is guided from the cooling air supply device 22 through the cooling air pipes 20a, 20b, 20c corresponding to the selected valve, and is supplied to each part in the upper casing 1 to forcibly cool the upper casing 1.

As described above, a plurality of cooling air pipes 20a, 20b, 20c provided by specifying a plurality of locations in the upper casing 1 can be selected, so that the temperature balance over a wide area in the upper casing 1 can be improved. Since the temperature of the upper casing 1 can be reduced with consideration and the influence of natural convection from the lower casing 2 can be reduced, the temperature difference between the upper casing 1 and the lower casing 2 constituting the outer casing can be more effectively reduced. Can be.

According to the present embodiment, the upper casing 1 and the lower casing 2 constituting the outer casing are restrained from being warped upward in the convex shape due to the difference in axial expansion between the upper casing 1 and the lower casing 2. As a result, the clearance between the stationary portions of the inner casings 3 and 4 and the rotating portion of the rotor 19 can be secured, the contact between the stationary portion and the rotating portion can be avoided, and there is no need to perform forced cooling stop. In addition, advantages such as a reduction in fuel cost can be obtained.

Next, a third embodiment of the present invention will be described with reference to FIG.
It will be described based on. Note that the present embodiment is based on the first and second embodiments described above, and is an improvement of the main part of the configuration in each embodiment.

In this embodiment, the first and second embodiments described above are used.
The cooling air pipe 20 or the cooling air pipes 20a, 20b, 20c, which are the main components in the embodiment, have improved portions connected to the outer casing. Therefore, FIG. 5 shows the first and second embodiments of the present invention. FIG. 5 shows a portion corresponding to the portion A in FIGS.

In order to prevent the description from being redundant,
The same parts as those in the first and second embodiments described above are denoted by the same reference numerals in the drawings, and overlapping description will be omitted as much as possible, and points specific to the present embodiment will be mainly described.

That is, according to the present embodiment, a projecting portion 29 is provided at the end of the cooling air pipe 20 at a portion where the cooling air pipe 20 communicating with a cooling air supply device (not shown) is opened to the upper casing 1. A plurality of cooling air discharge ports 25 are pierced in this protruding portion 29 so that the opening 2 of the cooling air pipe 20 is formed.
6.

In the example shown in the figure, the cooling air discharge port 25 is perforated so as to open toward the upstream side.
The ejection direction of the cooling air 23 is shifted 360 degrees around the protruding portion 29.
゜ It can be set to spray.

In the illustrated example, the cooling air pipe 20 disposed at a position corresponding to the exhaust chamber of the high-pressure turbine is representatively shown. However, the present invention is not limited to this, and as shown in FIG. It can be applied to the upper casing 1 that opens at a position corresponding to an intermediate stage between the high-pressure turbine and the intermediate-pressure turbine, or that opens at a position corresponding to the entrance chamber of the intermediate-pressure turbine.

In this embodiment configured as described above, the cooling air pipe 20 (corresponding to 20a, 20b, and 20c in FIG. 4) is omitted from the illustration immediately after disconnection when the steam turbine is stopped. Cooling air 2 from the cooling air supply device
3 is supplied to each part in the upper casing 1 from the cooling air discharge port 25 to forcibly cool the upper casing 1.

As a result, the temperature of the upper passenger compartment 1 can be reduced and the influence of natural convection from the lower passenger compartment 2 can be reduced, so that the temperature difference between the upper passenger compartment 1 and the lower passenger compartment 2 constituting the outer passenger compartment can be reduced, and the outer passenger compartment can be reduced. The upper casing 1 and the lower casing 2 can be restrained from warping upward in the outer casing due to the difference in axial expansion between the upper casing 1 and the lower casing 2. Since contact between the unit and the rotating unit is avoided, and there is no need to perform forced cooling stop, advantages such as a reduction in fuel cost can be obtained.

In addition, since the cooling air pipe 20 (corresponding to 20a, 20b and 20c in FIG. 4) is rapidly cooled from a high temperature state during operation, cracks may be generated due to thermal shock. , Inspection and replacement are required, but in the present embodiment, the protruding portion 29 protrudes linearly,
Since there is no bend at the tip, the joint can be easily removed by removing the joint (usually joined by welding or the like) between the cooling air pipe 20 and the upper casing 1, thereby facilitating inspection or replacement. .

Next, a fourth embodiment of the present invention will be described with reference to FIG.
It will be described based on. This embodiment is based on the premise of the first and second embodiments, as in the third embodiment described above, and is a modification of the main part of the configuration in each embodiment.

This embodiment is similar to the first and second embodiments described above.
The main configuration of the embodiment is a cooling air pipe 20 or a part where the cooling air pipes 20a, 20b, 20c are connected to the outer casing. Therefore, FIG. 6A shows the first and second embodiments. 1 and 4 showing the two forms are shown, and FIG. 6B is a perspective view showing a main part of FIG.

In order to avoid a redundant description,
The same parts as those in the first, second and third embodiments are denoted by the same reference numerals in the drawings, and overlapping description will be omitted as much as possible.

That is, according to the present embodiment, a cooling air pipe 20 communicating with a cooling air supply device (not shown) is opened in the inner wall surface of the upper casing 1 and supplied to the opening 26 from the cooling air pipe 20. A disk-shaped plate member 24 against which cooling air 23 collides is attached to the inner wall of the upper casing 1 by a plurality of leg bars 27.

In the illustrated example, the cooling air pipe 20 disposed at a position corresponding to the high-pressure turbine exhaust chamber is representatively shown. However, the present invention is not limited to this, and the second embodiment shown in FIG. As in the embodiment, the upper chamber 1 opens at a position corresponding to an intermediate stage between the high-pressure turbine and the intermediate-pressure turbine, and can also be applied to an upper chamber 1 that opens at a position corresponding to the inlet chamber of the intermediate-pressure turbine. .

In the present embodiment configured as described above, immediately after disconnection when the steam turbine is stopped, the cooling air piping 20 (corresponding to 20a, 20b and 20c in FIG. 4) is omitted from the drawing. Cooling air 2 from the cooling air supply device
3 is collided with the disk member 24 from the cooling air pipe 20, and the collision air disperses the cooling air 23 into the upper casing 1 to forcibly cool the upper casing 1.

As a result, the cooling air 23 flows along the inner wall of the upper casing 1 and efficiently cools the upper casing 1 to lower the temperature of the upper casing 1 and reduce the influence of natural convection from the lower casing 2. Therefore, the temperature difference between the upper casing 1 and the lower casing 2 forming the outer casing is reduced, and the outer casing is moved upward due to the difference in the axial expansion between the upper casing 1 and the lower casing 2 forming the outer casing. As in the above-described embodiments, contact between the stationary portion and the rotating portion can be avoided, and there is no need to perform forced cooling stop. This leads to advantages such as saving in cost.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
It will be described based on. This embodiment is based on the premise that the first and second embodiments are the same as in the third and fourth embodiments described above, and is a modification of the main part of the configuration in each embodiment. It is.

This embodiment is the first and second embodiments described above.
The cooling air piping 20 or the cooling air piping 20a, 20b, 20c, which is the main configuration in the embodiment, is a part in which the portion connected to the outer casing is improved. Therefore, FIG. 7 shows the first and second embodiments of the embodiment. FIG. 5 shows a portion corresponding to the portion A in FIGS.

In order to avoid the description from being redundant,
The same parts as those in the first, second, third, and fourth embodiments described above are denoted by the same reference numerals in the drawings, and redundant description will be omitted as much as possible.

That is, in this embodiment, a cooling air pipe 20 communicating from a cooling air supply device (not shown) is opened in the inner wall surface of the upper casing 1, and a box type nozzle 28 is installed in the opening 26. Things.

Further, in the illustrated example, the cooling air pipe 20 disposed at a position corresponding to the high-pressure turbine exhaust chamber is representatively shown. However, the present invention is not limited to this, and the second embodiment shown in FIG. As in the embodiment, the upper chamber 1 opens at a position corresponding to an intermediate stage between the high-pressure turbine and the intermediate-pressure turbine, and can also be applied to an upper chamber 1 that opens at a position corresponding to the inlet chamber of the intermediate-pressure turbine. .

In this embodiment constructed as described above, the cooling air pipe 20 (corresponding to 20a, 20b, and 20c in FIG. 4) is omitted from the illustration immediately after disconnection when the steam turbine is stopped. Cooling air 2 from the cooling air supply device
3, the cooling air 23 is turned by the box-shaped nozzle 28 and sprayed along the inner wall surface of the upper casing 1 into the upper casing 1 to forcibly cool the upper casing 1.

As a result, the cooling air 23 flows along the inner wall of the upper casing 1 to efficiently cool the upper casing 1 to lower the temperature of the upper casing 1 and reduce the influence of natural convection from the lower casing 2. Therefore, the temperature difference between the upper casing 1 and the lower casing 2 forming the outer casing is reduced, and the outer casing is moved upward due to the difference in the axial expansion between the upper casing 1 and the lower casing 2 forming the outer casing. As in the above-described embodiments, contact between the stationary portion and the rotating portion can be avoided, and there is no need to perform forced cooling stop. This leads to advantages such as saving in cost.

By adjusting the direction and angle of the opening of the box-type nozzle 28, the cooling air can be blown out in the optimal direction along the convection direction in the vehicle cabin, so that the cooling efficiency can be improved. In addition, a structure in which the cooling air pipe 20 is not entirely inserted into the inner wall of the upper casing 1 can be adopted, so that the range of options in designing and manufacturing can be expanded.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
It will be described based on. Note that this embodiment is based on the premise of the first and second embodiments, respectively, as in the third to fifth embodiments described above, and is a modification of the main part of the configuration in each embodiment. It is.

This embodiment is similar to the first and second embodiments described above.
The cooling air pipe 20 or the cooling air pipes 20a, 20b, 20c, which is the main configuration in the embodiment, has an improved portion connected to the outer casing. Therefore, FIG. 8 shows the first and second embodiments of the embodiment. FIG. 5 shows a portion corresponding to the portion A in FIGS.

In order to prevent the description from being redundant,
The same parts as those in the above-described first to fifth embodiments are denoted by the same reference numerals in the drawings, and redundant description will be omitted as much as possible.
The following description focuses on the features of the present embodiment.

That is, in the present embodiment, a cooling air pipe 20 communicating from a cooling air supply device (not shown) is obliquely connected to the upper casing 1 toward the upstream side, and the inside of the upper casing 1 This constitutes an opening 26 in the wall surface.

In the illustrated example, the cooling air pipe 20 disposed at a position corresponding to the high pressure turbine exhaust chamber is representatively shown. However, the present invention is not limited to this, and the second embodiment shown in FIG. As in the embodiment, the upper chamber 1 opens at a position corresponding to an intermediate stage between the high-pressure turbine and the intermediate-pressure turbine, and can also be applied to an upper chamber 1 that opens at a position corresponding to the inlet chamber of the intermediate-pressure turbine. .

In this embodiment configured as described above, immediately after disconnection when the steam turbine is stopped, the cooling air piping 20 (corresponding to 20a, 20b and 20c in FIG. 4) is omitted from the drawing. Cooling air 2 from the cooling air supply device
3, the cooling air 23 is blown out of the opening 26 along the inner wall of the upper casing 1 into the upper casing 1 to forcibly cool the upper casing 1.

As a result, the cooling air 23 can blow out the cooling air along the inner wall of the upper casing 1 without requiring components such as nozzles, so that the upper casing 1 is efficiently cooled and the temperature of the upper casing 1 is reduced. And the effect of natural convection from the lower passenger compartment 2 can be reduced, so that the temperature difference between the upper passenger compartment 1 and the lower passenger compartment 2 constituting the outer passenger compartment is reduced, and the upper passenger compartment 1 and the lower passenger compartment 2 forming the outer passenger compartment are reduced. The outer casing can be restrained from warping upward due to the difference in axial extension of the upper part, and contact between the stationary part and the rotating part is avoided as in the above embodiments, Further, since there is no need to perform forced cooling stop, advantages such as reduction of fuel cost can be obtained.

The cooling air piping 20 for the upper casing 1
It is sufficient that the opening 26 is open toward the upstream side, and the cooling air pipe 20 does not have to be inserted to the inner wall of the upper casing 1. The width can be expanded.

Although the present invention has been described with reference to the illustrated embodiments, the present invention is not limited to such embodiments.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0075]

As described above, according to the first aspect of the present invention, in the outer casing of the steam turbine constituted by the upper casing and the lower casing, the upper casing is opened to communicate with the cooling air supply device provided outside. The steam turbine casing is provided by providing cooling air pipes, and the cooling air pipes supply cooling air from an external cooling air supply device to the upper casing to cool the upper casing, thereby dismounting. Since the temperature of the upper compartment, which is higher than the temperature of the compartment, is lowered, and the temperature difference between the upper and lower compartments is reduced,
The difference in axial expansion between the upper and lower cabin is reduced, preventing contact between the stationary part and the rotating part, eliminating the need for forced cooling stop operation and greatly reducing fuel costs. It is.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of cooling air pipes are provided and opened at a plurality of locations in the upper compartment to form a steam turbine compartment. Therefore, cooling air is supplied from an external cooling air supply device to the upper cabin through cooling air pipes opened at multiple locations in the upper cabin, and the upper cabin is cooled faster and more appropriately to get off the upper The temperature difference between the compartments is reduced, the difference in the axial expansion between the upper and lower compartments is reduced to prevent contact between the stationary part and the rotating part, and there is no need to perform forced cooling stop operation,
The fuel cost was greatly reduced.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the cooling air pipe has a tip protruding into the upper passenger compartment and passes through a number of cooling air discharge holes provided in the protruding portion. Since the steam turbine cabin is formed by opening into the upper cabin, the steam is supplied from an external cooling air supply device through a cooling air pipe, and a large number of cooling air discharge holes provided at a protruding portion at a tip end thereof are used. The cooling air supplied to the vehicle interior is suitably dispersed in the upper vehicle interior by the same number of cooling air discharge holes, and the upper vehicle interior is appropriately cooled from the inside to reduce the temperature difference between the upper vehicle interior and the lower vehicle interior. By reducing the difference between the upper and lower compartments in the axial direction to prevent contact between the stationary part and the rotating part, there is no need to perform forced cooling stop operation, greatly reducing fuel costs. Was made.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the cooling air pipe has an end opening at the wall surface of the upper passenger compartment, and cooling air supplied from the opening collides. The cooling air supplied from the external cooling air supply device through the cooling air pipe is the energy that has collided with the plate member. It is dispersed in the upper passenger compartment with
Appropriately cooling the upper cabin to reduce the temperature difference between the upper and lower cabin, and reduce the axial expansion difference between the upper and lower cabin to prevent contact between the stationary part and the rotating part. In addition, there is no need to perform a forced cooling stop operation, and the fuel cost can be greatly reduced.

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the cooling air pipe has an opening at a tip end on the wall surface of the upper passenger compartment, and a box type nozzle is installed at the opening. The cooling air supplied from the external cooling air supply device through the cooling air pipe is turned by the box-type nozzle and sprayed into the upper vehicle compartment along the upper vehicle interior wall surface because it constitutes the steam turbine compartment. The upper compartment is appropriately cooled from the inside to reduce the temperature difference between the upper and lower compartments, and the difference in the axial extension between the upper and lower compartments to reduce the contact between the stationary part and the rotating part. This has prevented the occurrence of such a phenomenon, and there has been no need to perform a forced cooling stop operation, so that the fuel cost has been greatly reduced.

According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the cooling air pipe has a tip obliquely introduced into the upper compartment toward an upstream side, and the cooling air pipe is introduced into the upper compartment. The cooling air supplied from the external cooling air supply device through the cooling air pipe is opened from the wall surface to form the steam turbine cabin. The upper casing is appropriately cooled from the inside to reduce the temperature difference between the upper casing and the lower casing, and the difference in the axial expansion between the upper casing and the lower casing is reduced, and the stationary part and the rotating part are dispersed. Thus, the fuel cost can be greatly reduced by preventing the occurrence of contact with the fuel, and without the necessity of performing the forced cooling stop operation.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an axial cross-sectional structure of a steam turbine casing according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an enlarged cross section of a portion A in FIG. 1;

FIGS. 3A and 3B illustrate a state of a time change of an upper and lower metal temperature and an upper and lower temperature difference of the outer casing when the steam turbine is stopped, wherein FIG. 3A is a conventional one and FIG. It is explanatory drawing explaining what is in the form of FIG.

FIG. 4 is an explanatory diagram showing an axial cross-sectional structure of a steam turbine casing according to a second embodiment of the present invention.

FIG. 5 is an explanatory view showing, in an enlarged cross section, a main part of a steam turbine casing according to a third embodiment of the present invention, which corresponds to a portion A in FIG. 1 or FIG.

FIG. 6 is an enlarged cross-sectional view showing a main part of a steam turbine casing according to a fourth embodiment of the present invention, which corresponds to a portion A in FIG. 1 or FIG. 4;

FIG. 7 is an explanatory diagram showing an enlarged cross section of a main part of a steam turbine casing according to a fifth embodiment of the present invention, which corresponds to a portion A in FIG. 1 or FIG.

FIG. 8 is an explanatory diagram showing, in an enlarged cross section, a main part of a steam turbine casing according to a sixth embodiment of the present invention, which corresponds to a portion A in FIG. 1 or FIG. 4;

FIG. 9 is an explanatory view showing an axial sectional structure of a conventional steam turbine casing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper compartment 2 Lower compartment 3 Inner compartment 4 Inner compartment 5 Nozzle chamber 6, 7, 8 Blade ring 9 Main steam inlet 10 High pressure exhaust port 11 High pressure dummy bypass pipe 12 Medium pressure extraction port 13 High temperature reheat steam inlet 14 , 15 Medium-pressure exhaust port 19 Rotor 20 Cooling air pipe 20a, 20b, 20c Cooling air pipe 21a, 21b, 21c Valve 22 Cooling air supply device 23 Cooling air 24 Plate member 25 Cooling air outlet 26 Opening 27 Leg rod 28 Box Mold nozzle 29 Projecting part 30 High pressure turbine 40 Medium pressure turbine

Claims (6)

[Claims] 1. An outer casing of a steam turbine comprising an upper casing and a lower casing, wherein a cooling air pipe communicating with a cooling air supply device provided outside and opening to the upper casing is provided. Steam turbine cabin. 2. The steam turbine casing according to claim 1, wherein a plurality of cooling air pipes are provided and opened at a plurality of locations in the upper compartment. 3. The cooling air pipe according to claim 1, wherein a tip end of the cooling air pipe protrudes into the upper passenger compartment, and opens into the upper passenger compartment through a number of cooling air discharge holes provided in the protruding portion. The steam turbine casing as described. 4. The cooling air pipe is characterized in that a tip end is opened at the wall surface of the upper passenger compartment, and a plate member against which cooling air supplied from the opening collides is disposed facing the opening. The steam turbine casing according to claim 1. 5. The steam turbine casing according to claim 1, wherein a tip of the cooling air pipe is opened at a wall surface of the upper passenger compartment, and a box type nozzle is installed at the opening. 6. The steam turbine according to claim 1, wherein a tip end of the cooling air pipe is obliquely introduced into the upper casing toward an upstream side and is opened on a wall surface of the upper casing. Cabin.