JP2019157851A - Steam turbine exhaust device and steam turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam turbine exhaust device and a steam turbine capable of suppressing pressure loss. SOLUTION: In a steam turbine exhaust device for discharging steam worked in a turbine rotor from a turbine paragraph in the final stage through an exhaust chamber and an exhaust pipe, an upper half internal casing 3a having an upper half flange protruding into the exhaust chamber and exhaust. It consists of a lower half inner casing having a lower half flange protruding into the chamber, an inner casing in which the upper half flange and the lower half flange are joined at a joint to accommodate the turbine rotor, and an inner casing provided on the outer periphery of the inner casing. The outer casing 2 is provided between the two, and is formed between the outer casing and the turbines 3c and 3d located on the downstream side of the reference plane of the upper half flange or the lower half flange. The cross-sectional area of the exhaust chamber in the horizontal plane is equal to or larger than the cross-sectional area of the exhaust chamber formed between the joint portion and the outer casing in the horizontal plane. [Selection diagram] Fig. 2

Description

  Embodiments described herein relate generally to a steam turbine exhaust device and a steam turbine.

In a power generation plant, steam is generated in a boiler and is generated by being supplied to a turbine as a working fluid. In general, a power plant includes a plurality of turbines such as a high-pressure turbine, a medium-pressure turbine, and a low-pressure turbine. In the power plant, the steam is sequentially worked in each of the plurality of turbines, and then led to a condenser to be condensed. And the condensate condensed by the condenser is returned again to the boiler.

Each turbine is provided with an exhaust chamber inside an outer casing that houses the rotor, and steam flows from the turbine stage at the final stage to the exhaust chamber. This steam is guided from the exhaust chamber to the downstream equipment through the exhaust pipe.

Japanese Patent No. 4107766 Japanese Patent No. 5040156

A steam turbine according to related art will be described with reference to FIGS. 14 and 15. FIG.
FIG. 15 is a cross-sectional view of a steam turbine exhaust device according to related technology, and FIG. 15 is a cross-sectional view of another steam turbine exhaust device according to related technology. FIG. 14 and FIG. 15 are cross sections seen from the direction of the axis AX of the turbine rotor, and the arrows in the drawings indicate the flow of steam.

As shown in FIG. 14, the steam (exhaust gas) that has passed through the final stage of the steam turbine passes through the exhaust chamber 108 provided between the outer casing 102 and the inner casing 103, and from the upper half side (upper side in the z direction). After flowing to the lower half side, it is discharged from the exhaust pipe 109. The inner casing 103 is configured by combining an inner casing upper half 103a and an inner casing lower half 103b. A flange 103c is provided on the outer peripheral surface of the inner casing upper half 103a, and a flange 103d is provided on the outer peripheral surface of the inner casing lower half 103b. These are provided so as to protrude to the flow path side of the exhaust. Therefore, when the exhaust toward the exhaust pipe 109 passes in the vicinity of the upper half flange 103c and the lower half flange 103d, the cross-sectional area of the flow path decreases, the exhaust flow velocity increases, and pressure loss occurs.

As shown in FIG. 15, when one exhaust pipe 209 is provided in the circumferential direction, the exhaust chamber 20
Since the exhaust gas existing in the circumferential direction of 8 is directed to one exhaust pipe 209, this exhaust gas particularly has the exhaust chamber 2.
It tends to be turbulent on the exit side 208a of 08. Further, since the exhaust flow direction is deflected toward the exhaust pipe 209 on the outlet side 208a of the exhaust chamber 208, not only exhaust pressure loss due to turbulent flow but also exhaust pressure loss due to deflection may occur.

Therefore, the problem to be solved by the present invention is to provide a steam turbine exhaust device and a steam turbine capable of suppressing the pressure loss of the exhaust discharged from the exhaust chamber.

In order to solve the above-described problem, the turbine exhaust device according to the embodiment is a steam turbine exhaust device that discharges steam that has worked in a turbine rotor from the turbine stage of the final stage through the exhaust chamber and from the exhaust pipe. An upper half inner casing having a projecting upper half flange and a lower half inner casing having a lower half flange projecting into the exhaust chamber, wherein the upper half flange and the lower half flange are coupled at a coupling portion to An inner casing to be accommodated, and an outer casing provided on an outer periphery of the inner casing and forming the exhaust chamber between the inner casing, the outer casing, and the upper half flange or the lower half flange. Of these, in the horizontal plane of the exhaust chamber formed between the flange located downstream of the reference plane. The cross-sectional area that is greater than or equal to the cross-sectional area in the horizontal plane of the exhaust chamber formed between the outer casing and the coupling portion.

In another embodiment, the turbine exhaust device rotates the turbine rotor by expansion work from steam supplied from the outside, and exhausts the steam that has passed through the final stage of the turbine rotor from the exhaust chamber as exhaust. In the steam turbine exhaust apparatus, an outer casing that is provided on an outer periphery of an inner casing that houses the turbine rotor and that forms the exhaust chamber together with the inner casing, and an exhaust pipe that discharges the exhaust from the exhaust chamber to the outside And a pipe for connecting the exhaust pipe to the outer casing, and a connection pipe whose flow path cross-sectional area perpendicular to the flow direction decreases from the upstream side toward the downstream side.

  According to the embodiment of the present invention, the pressure loss of the exhaust discharged from the exhaust chamber can be suppressed.

It is a mimetic diagram of a steam turbine containing a steam turbine exhaust device concerning a first embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on 1st embodiment. It is the schematic perspective view which extracted the outer casing of the steam turbine exhaust apparatus which concerns on 1st embodiment. It is a horizontal sectional view of the lower half side of the steam turbine exhaust device according to the first embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on the modification of 2nd embodiment. It is sectional drawing of the steam-turbine exhaust apparatus vicinity which concerns on 2nd embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on the modification of 2nd embodiment. It is a horizontal sectional view of the lower half side of the steam turbine exhaust device according to the third embodiment. It is a schematic diagram of the steam turbine containing the steam turbine exhaust apparatus which concerns on 4th embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on 4th embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on the modification of 4th embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on the other modification of 4th embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on the other modification of 4th embodiment. It is sectional drawing of the steam turbine exhaust apparatus which concerns on related technology. It is sectional drawing of the other steam turbine exhaust apparatus which concerns on related technology.

  Hereinafter, the steam turbine exhaust device and the steam turbine according to the embodiment will be described.

(First embodiment)
First, a steam turbine exhaust device and a steam turbine according to the first embodiment will be described with reference to FIG.
Will be described. FIG. 1 is a schematic diagram of a steam turbine including a steam turbine exhaust apparatus according to an embodiment, and arrows shown in the figure represent the flow of exhaust. The exhaust here refers to the steam after passing through the final stage of the steam turbine 1.

As shown in FIG. 1, a steam turbine 1 according to an embodiment includes an outer casing 2, an inner casing 3, a turbine rotor 4, a steam inlet 5, a moving blade 6, a stationary blade 7, and a steam turbine exhaust device. 10 Here, a high pressure turbine will be described as an example of the steam turbine 1, but the steam turbine 1 may be, for example, an intermediate pressure turbine.

The steam turbine 1 introduces steam from a steam inlet 5 provided at one end of the turbine rotor 4. The steam is subjected to expansion work in a turbine stage configured by combining a plurality of moving blades 6 and stationary blades 7, and then is sent to a boiler (not shown) as exhaust gas through a steam turbine exhaust device 10. The exhaust gas sent to the boiler is heated again and then sent to a low-pressure turbine (not shown) where it works.

The outer casing 2 is configured by combining the upper half and the lower half, and is provided on the outer periphery of the inner casing 3. That is, the outer casing 2 accommodates the inner casing 3 therein. Details of the outer casing 2 will be described later.

The inner casing 3 is configured by combining the inner casing upper half 3a and the inner casing lower half 3b, and accommodates the turbine rotor 4 therein. The inner casing upper half 3a and the inner casing lower half 3b are in the circumferential direction of the turbine rotor 4 (rotation direction about the rotation axis AX).
The stationary blades 7 arranged at intervals are supported on the inner peripheral surface thereof. In addition, the inner casing upper half 3a and the inner casing lower half 3b are connected to each other in order to couple each other.
A flange 3c is provided on the outer peripheral surface of a, and a flange 3d is provided on the outer peripheral surface of the inner casing lower half 3b.
Each is provided protruding toward the exhaust chamber 8 side.

The steam turbine exhaust apparatus 10 is an apparatus that is provided on the final stage side of the turbine stage and guides exhaust after working in the steam turbine to a low-pressure turbine that is a further downstream facility. The steam turbine exhaust device 10 includes an exhaust chamber 8 and an exhaust pipe 9.

The exhaust chamber 8 is an exhaust passage provided between the inner peripheral surface of the outer casing 2 and the outer peripheral surface of the inner casing 3. That is, the exhaust chamber 8 is an exhaust passage constituted by the outer casing 2 and the inner casing 3 on the final stage side.

The exhaust pipe 9 is a pipe that discharges the exhaust to the outside, and extends downward from the outlet side of the outer casing 2 in the vertical direction (z direction). That is, in this embodiment, the downward direction in the vertical direction (z direction) is the downstream side in the exhaust flow direction. In the present embodiment, the case where the exhaust pipe 9 extends on the downstream side in the vertical direction will be described as an example. However, the configuration of the exhaust pipe 9 is not limited to the above case,
For example, the exhaust pipe 9 may be configured to extend upward in the vertical direction (z direction).

Next, the structure of the inner peripheral surface of the outer casing 2 will be described with reference to FIGS. 2 is a cross-sectional view of the steam turbine exhaust apparatus according to the first embodiment, FIG. 3 is a schematic perspective view of the extracted outer casing of the steam turbine exhaust apparatus according to the first embodiment, and FIG. The horizontal sectional view of the steam turbine exhaust apparatus which concerns on 1st embodiment is shown, respectively. The cross section of FIG. 2 is a cross section (yz plane) seen from the direction of the axis AX of the turbine rotor. FIG. 4 is an enlarged view of the horizontal section (xy plane) of FIG.

As shown in FIG. 2, the inner peripheral surface 2a of the outer casing 2 facing the surface 11d of the flange 3d, which is a flange located on the downstream side, of the inner peripheral surface of the outer casing 2 is parallel to the surface 11d.

As shown in FIGS. 3 and 4, the inner peripheral surface 2 a has a surface facing the surface 11 d so that the surface 1
It extends in the direction of the axis AX of the turbine rotor so as to be parallel to 1d.

By making the inner peripheral surface 2a of the outer casing 2 parallel to the surface 11d of the flange 3d, the cross-sectional area on the downstream side of the exhaust chamber 8 is such that the exhaust chamber 8 at the connecting portion of the inner casing upper half 3a and the inner casing lower half 3b. More than the cross-sectional area. The cross-sectional area of the exhaust chamber 8 here refers to the cross-sectional area of the flow path in a cross section perpendicular to the exhaust flow direction. Therefore, in the exhaust chamber 8, the cross-sectional area of the exhaust passage that passes from the upper half side to the lower half side does not decrease, and the exhaust flow velocity does not increase abruptly.

According to the first embodiment described above, among the inner peripheral surfaces of the outer casing 2, the inner peripheral surface 2a facing the surface 11d of the flange 3d is made parallel to the surface 11d of the flange 3d, thereby increasing the number of components. The pressure loss of the exhaust discharged from the exhaust chamber 8 to the exhaust pipe 9 can be suppressed without any problems.

In the first embodiment, the case where the inner peripheral surface 2a of the outer casing 2 facing the surface 11d of the flange 3d is parallel to the surface 11d has been described as an example, but this inner peripheral surface 2a is at least The portion facing the surface 11d may be parallel to the surface 11d. For example, as shown in FIG. 5, the inner peripheral surface 2a of the outer casing 2 is extended vertically (z direction) and connected to the inner peripheral surface of the exhaust pipe 9. You may let them.

(Second embodiment)
Next, a steam turbine exhaust device and a steam turbine according to the second embodiment will be described with reference to FIG.
Will be described. FIG. 6 is a cross-sectional view of the steam turbine exhaust device according to the second embodiment. In addition, description is abbreviate | omitted about the location which overlaps with 1st embodiment.

In the steam turbine exhaust system according to the second embodiment, the difference from the first embodiment is that the surface 11d of the flange 3d is replaced with the inner peripheral surface 2a provided in the outer casing 2 of the first embodiment. This is to provide the inner peripheral surface 2b of the opposing outer casing 2. As shown in FIG. 6, the inner peripheral surface 2b is uniformly inclined from the reference surface to the outer peripheral surface side of the outer casing 2 with a vertical surface (xz surface) parallel to the surface 11d of the flange 3d as a reference surface. Yes. This inclination is preferably such that the flow rate of the exhaust gas passing through the exhaust chamber 8 does not change abruptly, for example, the inclination angle from the reference plane (xz plane) is 45 degrees or less. By adopting such a structure, the cross-sectional area on the downstream side of the exhaust chamber 8 becomes larger than the cross-sectional area of the exhaust chamber 8 at the joint portion of the inner casing upper half 3a and the inner casing lower half 3b, thereby reducing the pressure loss of the exhaust. Can be suppressed.

According to the second embodiment described above, the surface 11 d of the flange 3 d of the outer casing 2.
By tilting the inner peripheral surface 2b opposite to the outer peripheral surface side of the outer casing 2, the same effect as in the first embodiment can be obtained.

In addition, although 2nd embodiment illustrated and demonstrated the case where the inclination of the internal peripheral surface 2b was uniform, this internal peripheral surface is inclined toward the outer peripheral surface side of the outer casing 2 as it goes downstream. For example, as shown in FIG. 7, the inner peripheral surface 2b may be a curved surface when viewed from the axial direction.

(Third embodiment)
Next, a steam turbine exhaust device and a steam turbine according to the third embodiment will be described with reference to FIG.
Will be described. FIG. 8 is a horizontal sectional view of the steam turbine exhaust device according to the third embodiment. In addition, description is abbreviate | omitted about the location which overlaps with 1st embodiment.

In the steam turbine exhaust apparatus according to the third embodiment, the difference from the first and second embodiments is that the inner peripheral surface 2c of the outer casing 2 facing the surface 11d of the flange 3d is bent in the direction of the axis AX. It is a point that becomes a curved surface. The inner peripheral surface 2c is inclined from the reference surface to the outer peripheral surface side of the outer casing 2 with a vertical surface (xz surface) parallel to the surface 11d of the flange 3d as a reference surface. This inclination is preferably provided such that the flow rate of the exhaust gas passing through the exhaust chamber 8 does not change rapidly, for example, the change in the flow rate of the exhaust gas is within 10%. By adopting such a structure, the cross-sectional area on the downstream side of the exhaust chamber 8 becomes larger than the cross-sectional area of the exhaust chamber 8 at the joint portion of the inner casing upper half 3a and the inner casing lower half 3b, thereby reducing the pressure loss of the exhaust. Can be suppressed.

According to the third embodiment described above, the surface 11 d of the flange 3 d of the outer casing 2.
By bending the inner peripheral surface 2c opposite to the direction of the axis AX, the same effect as in the first and second embodiments can be obtained.

(Fourth embodiment)
Next, a steam turbine exhaust device and a steam turbine according to the fourth embodiment will be described with reference to FIG.
Will be described. FIG. 9 is a schematic diagram of a steam turbine including a steam turbine exhaust device according to the fourth embodiment. In addition, the same code | symbol is attached | subjected and demonstrated about the location which overlaps with 1st to 3rd embodiment.

As shown in FIG. 9, the steam turbine 1 includes an outer casing 12, an inner casing 3,
A turbine rotor 4, a steam inlet 5, a moving blade 6, a stationary blade 7, and a steam turbine exhaust device 20 are provided. This embodiment is characterized in that a steam turbine exhaust device 20 described later is provided instead of the steam turbine exhaust device 10 in the first to third embodiments.

The outer casing 12 is a casing of the steam turbine 1 and is provided on the outer periphery of the inner casing 3. That is, the outer casing 12 accommodates the inner casing 3 therein. A flange 12 a is provided on the outlet side of the outer casing 12 that discharges exhaust gas from the outer casing 12. Other configurations are the same as those of the outer casing 2 in the first embodiment.
That is, the surface 11d of the flange 3d of the lower half 3b of the inner casing and the inner peripheral surface 2a facing the surface 11d are designed to be parallel to each other, and the cross-sectional area on the downstream side of the exhaust chamber 18 (inside the outer casing 12). The cross-sectional area of the flow path provided between the peripheral surface 2a and the inner casing 3) is the exhaust chamber 18 in the joint portion of the inner casing upper half 3a and the inner casing lower half 3b.
Or a cross-sectional area of a flow path provided between the outer casing 12 and the inner casing 3 in a horizontal cross section including a coupling portion.

Next, the steam turbine exhaust device 20 shown in FIG. 9 will be further described with reference to FIG. FIG. 10 is a cross-sectional view of a steam turbine exhaust device according to the fourth embodiment.

As shown in FIG. 10, the steam turbine exhaust device 20 is provided on the final stage side of the turbine stage, and guides the exhaust after working in the steam turbine 1 to a low-pressure turbine or condenser that is a downstream facility. Device. The steam turbine exhaust device 20 includes an exhaust chamber 18, an exhaust pipe 19, and a connecting pipe 21.

The exhaust chamber 18 is a flow path provided between the outer casing 12 and the inner casing 3 and allows the exhaust gas that has passed through the final stage of the turbine to pass therethrough. That is, the exhaust chamber 18 is an exhaust flow path constituted by the outer casing 12 and the inner casing 3 on the turbine final stage side.

The exhaust pipe 19 is a pipe that discharges the exhaust to the outside, and extends upward in the vertical direction (z direction). That is, in the present embodiment, the upper side in the vertical direction (z direction) is the downstream side in the exhaust gas flow direction. Further, the exhaust pipe 19 is connected to the downstream side of the connection pipe 21. That is, the flange 21
a is the flange 12a of the outer casing 12, and flange 21b is the flange 1 of the exhaust pipe 19.
Each of the coupling surfaces is fastened and fixed by a fastening member such as a bolt. As a result, the exhaust chamber 18, the connecting pipe 21, and the exhaust pipe 19 are connected to form an exhaust passage.

The connecting pipe 21 is a pipe that connects the outer casing 12 and the exhaust pipe 19, and the exhaust chamber 18.
Together with this, an exhaust passage is formed. The connecting pipe 21 is provided with flanges 21a and 21b at the upstream and downstream ends of the exhaust, respectively. In addition, the connecting pipe 21 in this embodiment is
As the direction from the flange 21a side (upstream side) toward the flange 21b side (downstream side), the cross-sectional area of the flow path (cross-sectional area on the xy plane) gradually decreases at a constant rate (ie,
The connecting tube 21 is designed in the shape of a truncated cone.

Next, the operation of this embodiment will be described. Steam heated by a boiler (not shown) flows from the steam inlet 5 through the main steam pipe. This steam is supplied to the first stage of the turbine stage through a nozzle box (not shown), and sequentially passes through the moving blade 6 and the stationary blade 7 of each turbine stage. When the steam passes through the rotor blade 6, the steam performs an expansion work and rotates the turbine rotor 4 together with the rotor blade 6. When the turbine rotor 4 is rotationally driven, a generator (not shown) connected to the turbine rotor 4 via the rotating shaft is rotationally driven, and the generator converts the rotational energy into electric energy to generate electric power.

On the other hand, the steam that has passed through the final stage of the turbine is led from the exhaust chamber 18 to the connecting pipe 21 as exhaust. At this time, similarly to the first embodiment, the cross-sectional area on the downstream side of the exhaust chamber 18 is equal to or larger than the cross-sectional area at the joint portion of the inner casing upper half 3a and the inner casing lower half 3b. The flow velocity and flow direction of the exhaust gas passing through the lower half side from the air does not change abruptly.

Furthermore, the cross-sectional area (cross-sectional area on the xy plane) of the connecting pipe 21 decreases from the upstream side flange 21a side toward the downstream side flange 21b side. Therefore, when this exhaust gas is guided from the exhaust chamber 18 to the connecting pipe 21, the flow direction and flow velocity of the exhaust gas change gently. Therefore, the steam turbine exhaust device 20 can suppress not only the pressure loss of exhaust passing through the lower half to the upper half of the exhaust chamber 18 but also the pressure loss of exhaust led from the exhaust chamber 18 to the exhaust pipe 19.

According to the fourth embodiment described above, the inner peripheral surface 2a of the outer casing 12 and the surface 11d of the flange 3d of the lower half 3b of the inner casing are made parallel to each other and connected between the outer casing 12 and the exhaust pipe 19. By providing the pipe 21, not only the pressure loss when passing from the upstream side to the downstream side of the exhaust chamber 18, but also the pressure loss of the exhaust led from the exhaust chamber 18 to the exhaust pipe 19 can be suppressed.

In the present embodiment, the case where the connecting pipe 21 has a truncated cone shape is described as an example. However, the connecting pipe 21 has a configuration in which the cross-sectional area of the flow path decreases from the upstream side toward the downstream side. For example, a hyperboloid structure may be used. In addition, the configuration in which the cross-sectional area of the flow path decreases as it goes from the upstream side to the downstream side here is a case where the cross-sectional area of the flow path continuously decreases from the flange 21a on the upstream side to the flange 21b on the downstream side. However, the cross-sectional area may not be changed along the flow direction as in the case where the upstream side of the connecting pipe 21 has a truncated cone shape and the downstream side has a cylindrical shape.

Further, in the fourth embodiment described above, the case where the steam turbine exhaust device 20 is newly provided instead of the steam turbine exhaust device 10 in the first to third embodiments has been described as an example. To the steam turbine of the third embodiment.
It is good also as a structure which provided. That is, as shown in FIG. 11, the structure in which the outer casing 2 and the exhaust pipe 9 in the first embodiment are connected via the connecting pipe 21, or the outer casing in the second embodiment as shown in FIG. 12. 2 and the exhaust pipe 9 may be connected via a connecting pipe 21. Further, as in the third embodiment, the inner peripheral surface of the outer casing 2 is an axis AX.
In addition to the configuration of the inner peripheral surface 2c, which is a curved surface curved in the direction of, a structure in which the outer casing 2 and the exhaust pipe 9 are connected via a connecting pipe 21 may be used. Furthermore, for example, as shown in FIG. 13, the outer casing 12 whose inner peripheral surface is not processed (that is, a conventional outer casing).
On the other hand, the steam turbine exhaust device 20 may be provided.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1. Steam turbine 2,12. Outer casing, 2a, 2b, 2c. 2. Inner peripheral surface Inner casing, 3a. Inner casing upper half, 3b. Inner casing lower half, 3c, 3d, 12a
19b, 21a, 21b. Flange, 4. Turbine rotor, 5. Steam inlet, 6. Moving blade,
7). Static blade, 8, 18. Exhaust chamber, 9, 19. Exhaust pipes 10, 20,. Steam turbine exhaust system,
11c, 11d. Surface, 21. Connecting pipe

Claims (6)

In a steam turbine exhaust device that rotates a turbine rotor by expansion work from steam supplied from the outside and exhausts the steam that has passed through the final stage of the turbine rotor from an exhaust chamber to the outside,
An upper half inner casing having an upper half flange projecting into the exhaust chamber and a lower half inner casing having a lower half flange projecting into the exhaust chamber, wherein the upper half flange and the lower half flange are coupled at a coupling portion. An inner casing that houses the turbine rotor;
An outer casing provided on an outer periphery of the inner casing and forming the exhaust chamber with the inner casing;
With
A cross-sectional area in a horizontal plane of the exhaust chamber formed between the outer casing and a flange located on the downstream side of the reference surface among the upper half flange or the lower half flange is formed by the coupling portion and the A steam turbine exhaust apparatus having a cross-sectional area in a horizontal plane of the exhaust chamber formed between the outer casing and the outer casing. 2. The steam turbine exhaust device according to claim 1, wherein a surface of the outer casing facing a flange located on the downstream side is parallel to a surface of the flange located on the downstream side. 2. The steam turbine according to claim 1, wherein a surface of the outer casing that faces the flange located on the downstream side is formed so as to move away from the flange located on the downstream side as it goes downstream from the coupling portion. Exhaust system. The exhaust pipe is connected to the outer casing via a connecting pipe;
The steam turbine exhaust device according to any one of claims 1 to 3, wherein the connecting pipe has a flow passage cross-sectional area that is perpendicular to the flow direction as it goes from the upstream side to the downstream side. In a steam turbine exhaust device that rotates a turbine rotor by expansion work from steam supplied from the outside and exhausts the steam that has passed through the final stage of the turbine rotor from an exhaust chamber to the outside,
An outer casing provided on an outer periphery of an inner casing for accommodating the turbine rotor, and constituting the exhaust chamber together with the inner casing;
An exhaust pipe for discharging the steam from the exhaust chamber to the outside;
A pipe provided between the outer casing and the exhaust pipe, and a connecting pipe whose flow path cross-sectional area perpendicular to the flow direction becomes smaller from the upstream side toward the downstream side,
A steam turbine exhaust system comprising: A turbine rotor,
A moving blade provided in the rotation direction of the turbine rotor and rotating together with the turbine rotor by work of steam introduced from the outside;
A steam turbine exhaust device according to any of claims 1 to 5;
A steam turbine comprising:

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