JP6827765B2 - Steam turbine - Google Patents

Description

The present invention relates to a steam turbine.

The steam turbine includes a rotor that rotates about an axis and a casing that covers the rotor. The rotor has a plurality of moving blades arranged around a rotor shaft extending in the axial direction about the axis. The casing is provided with a plurality of stationary blades arranged around the rotor on the upstream side of the moving blades.

For example, Patent Document 1 describes a steam turbine having an inner casing to which a stationary blade is attached and an outer casing that covers the inner casing from the outside. In this steam turbine, a flow path for passing the working steam flowing through the working steam flow path between the inner casing and the rotor is formed between the outer casing and the inner casing. As a result, the outer casing and the inner casing are cooled by the working steam flowing through the flow path.

Japanese Unexamined Patent Publication No. 2012-107618

By the way, even when a flow path through which steam flows is formed between the outer casing and the inner casing as described above, depending on the operating conditions of the steam turbine, the tip of the rotor blade and the inner peripheral surface of the inner casing may be formed. There is a possibility that the clearance between the blade and the rotor will be inadvertently narrowed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a steam turbine capable of setting a clearance between the rotor side and the inner casing side to an appropriate value.

The present invention employs the following means in order to solve the above problems.
In the steam turbine according to one aspect of the present invention, a plurality of moving blades are provided on the outer peripheral surface, and the rotor is covered with a rotor that rotates around an axis and the rotor from the outside in the radial direction centered on the axis. An inner casing that defines a first main flow path through which steam flows with the outer peripheral surface of the inner casing, and a plurality of inner casings provided on the inner peripheral surface of the inner casing, together with the plurality of moving blades, in the first main flow path. The stationary blades arranged and the inner casing are covered from the outside in the radial direction, and the second main flow path communicating with the first main flow path and flowing the steam is drawn between the outer peripheral surface of the inner casing. The outer casing formed, the main steam supply unit that supplies the steam to the first main flow path, and a part of the steam supplied from the main steam supply unit to the first main flow path are separated and heated. The inner casing heating section includes an inner casing heating section that supplies steam to the inner casing and heats the inner casing, and the inner casing heating section uses steam different from the steam supplied from the main steam supply section as heating steam. The sub-steam supply unit has a sub-steam supply unit, and the sub-steam supply unit supplies the heated steam to the inner casing when the steam is not supplied from the main steam supply unit to the first main flow path.

With this configuration, the inner casing is heated by the steam flowing through the first main flow path, and is also heated by the heated steam. As a result, the inner casing can be expanded faster than the rotor. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are secured. Therefore, depending on the operating condition of the steam turbine, it is possible to prevent the tip of the moving blade from coming into contact with the inner peripheral surface of the inner casing, or the tip of the stationary blade from coming into contact with the outer peripheral surface of the rotor.
In addition, the inner casing expands with the heated steam before the rotor blades expand due to exposure to the steam flowing through the first main flow path. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing can be widened with high accuracy.

The steam turbine according to another aspect of the present invention, the pre-Symbol inner casing heating unit, a control unit for controlling the supply state of the heating steam, the control unit, flows the vapor on the first main channel The heated steam may be supplied until a predetermined condition that can be considered that the inner casing and the moving blade do not come into contact with each other is satisfied.

With this configuration, the inner casing continues to be heated until it can be considered that the inner casing and the rotor blades do not come into contact with each other. As a result, it is possible to prevent the tip of the rotor blade from coming into contact with the inner peripheral surface of the inner casing due to a narrow distance with high accuracy.

The present invention employs the following means in order to solve the above problems.
In the steam turbine according to another aspect of the present invention, a plurality of moving blades are provided on the outer peripheral surface to cover the rotor rotating around the axis and the rotor from the outside in the radial direction about the axis, and the rotor. A plurality of inner casings defining a first main flow path through which steam flows with the outer peripheral surface of the inner casing and a plurality of inner casing surfaces of the inner casing are provided in the first main flow path together with the plurality of moving blades. An arranged stationary blade and a second main flow path that covers the inner casing from the outside in the radial direction and communicates with the first main flow path to flow the steam are drawn between the outer peripheral surface of the inner casing. The outer casing, the main steam supply unit that supplies the steam to the first main flow path, and a part of the steam supplied from the main steam supply unit to the first main flow path are separated and heated. An inner casing heating unit that supplies steam to the inner casing and heats the inner casing is provided, and the inner casing heating unit stores a part of the steam supplied from the main steam supply unit in advance. The storage unit has a unit, and when the steam is not supplied from the main steam supply unit to the first main flow path, a part of the stored steam is used as the heating steam in the inner casing. to supply.

With this configuration, the inner casing is heated by the steam flowing through the first main flow path, and is also heated by the heated steam. As a result, the inner casing can be expanded faster than the rotor. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are secured. Therefore, depending on the operating condition of the steam turbine, it is possible to prevent the tip of the moving blade from coming into contact with the inner peripheral surface of the inner casing, or the tip of the stationary blade from coming into contact with the outer peripheral surface of the rotor.
Further, it is possible to prevent the inner casing from being cooled before the moving blades and narrowing the distance between the tip of the moving blades and the inner peripheral surface of the inner casing.

The steam turbine according to another aspect of the present invention, the pre-Symbol inner casing heating unit, may be merged with the heated steam to the steam flowing through the second main channel.

With this configuration, the heated steam that heated the inner casing flows through the second main flow path together with the steam that has flowed through the first main flow path. Therefore, the heated steam is discharged to the outside of the steam turbine together with the steam flowing through the first main flow path. Therefore, it is not necessary to newly provide a structure for discharging the heated steam. As a result, the inner casing heating portion can be formed with a simple structure.

The present invention employs the following means in order to solve the above problems.
In the steam turbine according to another aspect of the present invention, a plurality of moving blades are provided on the outer peripheral surface to cover the rotor rotating around the axis and the rotor from the outside in the radial direction about the axis, and the rotor. A plurality of inner casings defining a first main flow path through which steam flows with the outer peripheral surface of the inner casing and a plurality of inner casing surfaces of the inner casing are provided in the first main flow path together with the plurality of moving blades. An arranged stationary blade and a second main flow path that covers the inner casing from the outside in the radial direction and communicates with the first main flow path to flow the steam are drawn between the outer peripheral surface of the inner casing. The outer casing, the main steam supply unit that supplies the steam to the first main flow path, and a part of the steam supplied from the main steam supply unit to the first main flow path are separated and heated. The inner casing heating portion is provided as steam that is supplied to the inner casing to heat the inner casing, and the inner casing heating portion circulates the heated steam inside the inner casing.

With this configuration, the inner casing is heated by the steam flowing through the first main flow path, and is also heated by the heated steam. As a result, the inner casing can be expanded faster than the rotor. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are secured. Therefore, depending on the operating condition of the steam turbine, it is possible to prevent the tip of the moving blade from coming into contact with the inner peripheral surface of the inner casing, or the tip of the stationary blade from coming into contact with the outer peripheral surface of the rotor.
Further, the position near the inner peripheral surface of the inner casing is heated. As a result, the region of the inner casing close to the inner peripheral surface can be heated to expand the inner casing. As a result, the inner casing can be expanded faster. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are ensured with high accuracy.

The present invention employs the following means in order to solve the above problems.
In the steam turbine according to another aspect of the present invention, a plurality of moving blades are provided on the outer peripheral surface to cover the rotor rotating around the axis and the rotor from the outside in the radial direction about the axis, and the rotor. A plurality of inner casings defining a first main flow path through which steam flows with the outer peripheral surface of the inner casing and a plurality of inner casing surfaces of the inner casing are provided in the first main flow path together with the plurality of moving blades. An arranged stationary blade and a second main flow path that covers the inner casing from the outside in the radial direction and communicates with the first main flow path to flow the steam are drawn between the outer peripheral surface of the inner casing. The outer casing, the main steam supply unit that supplies the steam to the first main flow path, and a part of the steam supplied from the main steam supply unit to the first main flow path are separated and heated. An inner casing heating portion that is supplied as steam to the inner casing to heat the inner casing is provided, and the inner casing heating portion is separated from the outer peripheral surface of the inner casing in the axial direction in which the axis extends. Te is more disposed, and a steam flow portion along the outer circumferential surface circulating the heated steam in a circumferential direction about the axis of the inner casing.

With this configuration, the inner casing is heated by the steam flowing through the first main flow path, and is also heated by the heated steam. As a result, the inner casing can be expanded faster than the rotor. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are secured. Therefore, depending on the operating condition of the steam turbine, it is possible to prevent the tip of the moving blade from coming into contact with the inner peripheral surface of the inner casing, or the tip of the stationary blade from coming into contact with the outer peripheral surface of the rotor.
Further, the heated steam comes into contact with the outer peripheral surface of the inner casing without merging with the steam flowing through the second main flow path. Therefore, it is possible to prevent the temperature of the heated steam from being lowered by the steam flowing through the second main flow path. As a result, the inner casing can be expanded faster. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are ensured with high accuracy.

The steam turbine according to another aspect of the present invention, before Symbol inner casing heating unit may have a steam injection unit for injecting the heating steam toward the outer surface of the inner casing.

With this configuration, the heated steam is injected toward the outer peripheral surface of the inner casing without merging with the steam flowing through the second main flow path. Therefore, it is possible to prevent the temperature of the heated steam from being lowered by the steam flowing through the second main flow path. In addition, a high heat transfer effect due to the jet can be obtained. As a result, the inner casing can be expanded faster. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are ensured with high accuracy.

The steam turbine according to another aspect of the present invention, before Symbol inner casing protrudes toward the outer circumferential surface of the inner casing to the outside of the radial direction, has a projection portion disposed on the second main channel You may.

With this configuration, the surface area of the outer peripheral surface of the inner casing is increased. Therefore, the inner casing can be effectively heated from the outer peripheral surface side by the heating steam. As a result, the inner casing can be expanded faster. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are ensured with high accuracy.

The present invention employs the following means in order to solve the above problems.
In the steam turbine according to another aspect of the present invention, a plurality of moving blades are provided on the outer peripheral surface, and the rotor is covered with a rotor that rotates around an axis and the rotor from the outside in the radial direction about the axis. An inner casing that defines a first main flow path through which steam flows with the outer peripheral surface of the inner casing, and a plurality of inner casings provided on the inner peripheral surface of the inner casing, together with the plurality of moving blades, in the first main flow path. The stationary blades arranged and the inner casing are covered from the outside in the radial direction, and the second main flow path communicating with the first main flow path and flowing the steam is drawn between the outer peripheral surface of the inner casing. The outer casing formed, the main steam supply unit that supplies the steam to the first main flow path, and a part of the steam supplied from the main steam supply unit to the first main flow path are separated and heated. The inner casing is provided with an inner casing heating portion that is supplied as steam to the inner casing and heats the inner casing, and the inner casing is provided at the inner introduction port for introducing the steam into the first main flow path and the inner introduction port. On the other hand, an inlet communication section that communicates the first main flow path and the outside on the upstream side in the flow direction of steam flowing through the first main flow path, and an adjustment section that adjusts the flow state of the steam at the inlet communication section. the it has.

With this configuration, the inner casing is heated by the steam flowing through the first main flow path, and is also heated by the heated steam. As a result, the inner casing can be expanded faster than the rotor. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are secured. Therefore, depending on the operating condition of the steam turbine, it is possible to prevent the tip of the moving blade from coming into contact with the inner peripheral surface of the inner casing, or the tip of the stationary blade from coming into contact with the outer peripheral surface of the rotor.
Further, when the steam flows into the first main flow path, the steam flows into the inlet communication portion. Therefore, it is possible to heat the region forming the inner introduction portion in the inner casing. Therefore, in the inner casing, a region where the temperature does not easily rise can be heated and expanded.

The steam turbine according to another aspect of the present invention may be provided with a heater for heating the pre-Symbol inner casing.

With this configuration, the inner casing can be expanded significantly faster by heating the inner casing with the heater together with the heating steam. As a result, the clearance between the tip of the rotor blade and the inner peripheral surface of the inner casing and the clearance between the tip of the stationary blade and the outer peripheral surface of the rotor are ensured with high accuracy.

According to the present invention, the clearance between the rotor side and the inner casing side can be set to an appropriate value.

It is a schematic diagram which shows the structure of the steam turbine in the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the steam turbine in the 2nd Embodiment of this invention. It is a schematic diagram which shows the structure of the steam turbine in the 3rd Embodiment of this invention. It is a schematic diagram which shows the structure of the steam turbine in 4th Embodiment of this invention. It is a schematic diagram which shows the structure of the steam turbine in 5th Embodiment of this invention. It is a schematic diagram which shows the structure of the steam turbine in the 6th Embodiment of this invention. It is a schematic diagram which shows the structure of the steam turbine in the 7th Embodiment of this invention.

Hereinafter, the steam turbine according to the embodiment of the present invention will be described with reference to the drawings.
<< First Embodiment >>
The steam turbine 1 is an external combustion engine that extracts steam energy as rotational power, and is used for a generator or the like in a power plant. As shown in FIG. 1, the steam turbine 1 includes a rotor 2, an inner casing 3, a stationary blade 4, an outer casing 5, a bearing portion 6, a seal portion 7, a main steam supply portion 8, and an inner casing. It includes a heating unit 9.

The rotor 2 is rotatable about the axis O. The rotor 2 has a rotor main body 21 extending in the axial direction Da about the axis O, and a plurality of moving blades 22 fixed to the rotor main body 21 along the circumferential direction Dc with respect to the rotor main body 21. There is.

In the following, the direction in which the axis O extends is referred to as the axis direction Da. With the axis O as a reference, the direction orthogonal to the axis O is simply referred to as the radial direction Dr. The direction around the rotor 2 centered on the axis O is defined as the circumferential direction Dc.

In the rotor main body 21, an intermediate portion to which the moving blades 22 are fixed is housed inside the inner casing 3. Both ends of the rotor body 21 project to the outside of the outer casing 5. Both ends of the rotor body 21 projecting outward from the outer casing 5 are rotatably supported by bearings 6.

A plurality of rotor blades 22 are arranged side by side in the circumferential direction Dc with respect to the outer peripheral surface 2a facing the outside of the radial direction Dr of the rotor main body 21. The plurality of moving blades 22 are provided on the outer peripheral surface 2a of the rotor main body 21 in an annular shape and separated from each other in the axial direction Da. The rotor blade 22 rotates the rotor 2 around the axis O under the pressure of steam flowing in the axial direction Da of the rotor main body 21. The tip of the moving blade 22 facing the outside of the radial Dr is opposed to the inner peripheral surface 3a of the inner casing 3 facing the inside of the radial Dr at intervals.

The inner casing 3 covers the rotor 2 from the outside of the radial Dr. The inner casing 3 of the present embodiment has a tubular shape centered on the axis O. The inner casing 3 defines a first main flow path 31 through which steam flows between the inner peripheral surface 3a and the outer peripheral surface of the rotor 2.

The first main flow path 31 is a flow path through which steam extends in the axial direction Da between the inner peripheral surface 3a of the inner casing 3 and the outer peripheral surface 2a of the rotor main body 21. A moving blade 22 and a stationary blade 4 are arranged in the first main flow path 31. In the first main flow path 31 of the present embodiment, one side (first side) of the axial direction Da is the upstream side in the steam flow direction, and the other side (second side) of the axial direction Da is the downstream side in the steam flow direction. On the side, steam circulates.

The inner casing 3 has an inner introduction port 32 for introducing steam into the first main flow path 31, and an inner discharge port 33 for introducing steam into the second main flow path 51, which will be described later.

The inner introduction port 32 allows steam introduced through the outer casing 5 to flow into the first main flow path 31. The inner introduction port 32 communicates with the first main flow path 31 on one side of the axial direction Da. The inner introduction port 32 is formed in the inner casing 3 so as to extend from the outside of the radial Dr to the inside to the first main flow path 31. The inner introduction port 32 of the present embodiment is formed at two locations separated from each other in the circumferential direction Dc.

The inner discharge port 33 discharges steam from the first main flow path 31. The inner discharge port 33 communicates with the first main flow path 31 on the other side in the axial direction Da. The inner discharge port 33 of the present embodiment is an opening formed at the other end of the inner casing 3 in the axial direction Da. The inner discharge port 33 causes the steam flowing through the first main flow path 31 to flow into the second main flow path 51, which will be described later.

A plurality of stationary blades 4 are provided on the inner peripheral surface 3a of the inner casing 3 side by side along the circumferential direction Dc of the rotor 2. The stationary blades 4 are arranged at intervals in the radial direction Dr with respect to the outer peripheral surface 2a of the rotor main body 21. The tip of the stationary blade 4 facing inward in the radial direction is opposed to the outer peripheral surface 2a of the rotor main body 21 at a distance.

The outer casing 5 covers the inner casing 3 from the outside in the radial direction Dr. The outer casing 5 of the present embodiment has a bottomed tubular shape centered on the axis O. The outer casing 5 defines a second main flow path 51 through which steam flows between an inner peripheral surface 5a facing inward in the radial direction and an outer peripheral surface 3b of the inner casing 3.

The second main flow path 51 is a flow path of steam extending in the axial direction Da between the inner peripheral surface 5a of the outer casing 5 and the outer peripheral surface 3b of the inner casing 3. The second main flow path 51 communicates with the first main flow path 31. The steam flowing through the first main flow path 31 flows through the second main flow path 51. In the second main flow path 51 of the present embodiment, steam flows with one side of the axial direction Da as the downstream side in the steam flow direction and the other side of the axial direction Da as the upstream side in the steam flow direction.

The outer casing 5 has an outer introduction port 52 for introducing steam into the inner introduction port 32 and an outer discharge port 53 for discharging the steam flowing through the second main flow path 51 to the outside.

The outer introduction port 52 allows the steam supplied from the main steam supply unit 8 to flow into the outer casing 5. The outer introduction port 52 of the present embodiment is a through hole that communicates with the inside and the outside of the outer casing 5. The outer introduction port 52 is formed in the outer casing 5 at the same position as the inner introduction port 32 in the axial direction Da. The outer introduction port 52 is formed outside the radial direction Dr of the inner introduction port 32. The outer introduction port 52 is formed at two positions separated from each other in the circumferential direction Dc so that the position of the circumferential direction Dc is the same as that of the inner introduction port 32. Therefore, the outer introduction port 52 allows the steam supplied from the main steam supply unit 8 to flow into the inner introduction port 32.

The outer discharge port 53 is formed in the outer casing 5 on one side of the axial direction Da with respect to the outer introduction port 52. The outer discharge port 53 of the present embodiment is a through hole that communicates with the inside and the outside of the outer casing 5. The outer discharge port 53 discharges steam from the second main flow path 51 to the outside of the radial Dr. The outer discharge port 53 is formed at two positions apart from each other so that the position of the circumferential Dc is the same as that of the outer introduction port 52.

The bearing portion 6 rotatably supports the rotor 2 around the axis O. The bearing portion 6 is outside the outer casing 5 and is provided at both ends of the rotor main body 21.

The seal portion 7 seals between the rotor main body 21 and the inner casing 3 and between the rotor main body 21 and the outer casing 5 so that steam does not flow out. The seal portion 7 of the present embodiment has an inner seal portion 71 that seals between the inner casing 3 and the rotor main body 21, and an outer seal portion 72 that seals between the outer casing 5 and the rotor main body 21.

The inner sealing portion 71 seals between the rotor main body 21 and the inner casing 3 on one side of the axial direction Da from the first main flow path 31. The inner seal portion 71 is sealed from one side of the axial direction Da to the second main flow path 51 so that the steam flowing through the first main flow path 31 does not flow out. The inner seal portion 71 is provided on one side of the axial direction Da with respect to the inner introduction port 32.

The outer sealing portion 72 seals between the rotor main body 21 and the outer casing 5 on the outer side of the second main flow path 51 in the axial direction Da. The outer seal portion 72 is sealed from both ends in the axial direction Da to the outside of the outer casing 5 so that steam flowing through the second main flow path 51 does not flow out. The outer seal portion 72 is provided inside the bearing portion 6 in the axial direction Da.

The main steam supply unit 8 supplies steam to the first main flow path 31 from a supply source (not shown). The main steam supply unit 8 of the present embodiment has a main steam pipe 81 and a main steam valve unit 82.

The main steam pipe 81 sends steam from a supply source (not shown) to the outer introduction port 52. The main steam pipe 81 is a pipe connected to the outer introduction port 52. The main steam supply unit 8 connects the supply source and the outer introduction port 52.

The main steam valve portion 82 makes it possible to adjust the flow state of steam flowing through the main steam pipe 81. The main steam valve portion 82 is provided in the middle of the main steam pipe 81. The main steam valve unit 82 is opened or closed in response to a start schedule or stop schedule signal input from the control unit 200, which will be described later. As the main steam valve portion 82, for example, a solenoid valve is used.

The inner casing heating unit 9 divides a part of the steam (main steam) supplied from the main steam supply unit 8 to the first main flow path 31 and supplies it as heated steam to the inner casing 3 to heat the inner casing 3. .. Here, the heated steam is steam supplied to heat the inner casing 3. The inner casing heating unit 9 of the present embodiment merges the heated steam with the steam flowing through the second main flow path 51. As a result, the inner casing heating unit 9 indirectly supplies the heating steam to the inner casing 3 to heat the inner casing 3. The inner casing heating unit 9 includes a heated steam introduction unit 97, an auxiliary steam supply unit 98, a storage unit 99, a first supply pipe 91, a second supply pipe 92, a third supply pipe 93, and a fourth supply. The pipe 94, the fifth supply pipe 95, the first valve part 101, the second valve part 102, the third valve part 103, the fourth valve part 104, the fifth valve part 105, and the temperature measuring part 100. And a control unit 200.

The heated steam introduction unit 97 is a supply port for supplying the heated steam to the inside of the outer casing 5. The heated steam introduction unit 97 of the present embodiment supplies steam to the second main flow path 51 from the outside of the radial direction Dr. The heated steam introduction portion 97 is formed in the outer casing 5 on the other side in the axial direction Da from the outer introduction port 52. The heated steam introduction portion 97 is a through hole that communicates with the inside and the outside of the outer casing 5. The heated steam introduction unit 97 is formed at two locations separated from each other in the circumferential direction Dc so that the position of the circumferential direction Dc is the same as that of the outer introduction port 52. The heated steam introduction portion 97 is formed at a position where the position in the axial direction Da faces the outer peripheral surface 3b of the inner casing 3. The heated steam introduction unit 97 is preferably formed so that the position in the axial direction Da is close to the inner discharge port 33. That is, it is preferable that the position of the heated steam introduction section 97 in the axial direction Da is as upstream as possible with respect to the steam flow direction of the second main flow path 51.

The sub-steam supply unit 98 supplies steam different from the steam supplied from the main steam supply unit 8 as heated steam. The sub-steam supply unit 98 supplies heated steam to the inner casing 3 when steam is not supplied from the main steam supply unit 8 to the first main flow path 31. The sub-steam supply unit 98 of the present embodiment supplies steam having a temperature lower than that of the steam supplied from the main steam supply unit 8 as heated steam. Examples of the sub-steam supply unit 98 include an auxiliary boiler, a centrifugal compressor, and other steam turbines.

Although only one sub-steam supply unit 98 is provided in the present embodiment, the sub-steam supply unit 98 is not limited to such a configuration. For example, a plurality of sub-steam supply units 98 may be provided for one steam turbine 1, such as an auxiliary boiler and a centrifugal compressor installed separately.

The storage unit 99 stores a part of the steam supplied from the main steam supply unit 8 in advance. The storage unit 99 stores a part of the steam while the steam is supplied from the main steam supply unit 8 to the first main flow path 31. When the steam is not supplied from the main steam supply unit 8 to the first main flow path 31, the storage unit 99 supplies a part of the stored steam as heated steam to the inner casing 3. The storage unit 99 of the present embodiment stores steam by splitting and supplying a part of the steam flowing through the main steam pipe 81.

The first supply pipe 91 sends a part of the steam supplied from the main steam supply unit 8 to the heated steam introduction unit 97. The first supply pipe 91 is a pipe that connects the main steam pipe 81 and the heated steam introduction unit 97. One end of the first supply pipe 91 is connected in the middle of the main steam pipe 81. Specifically, one end of the first supply pipe 91 is connected to the steam pipe so as to branch off from the main steam pipe 81 on the steam supply source side of the main steam valve portion 82. The other end of the first supply pipe 91 is connected to the heated steam introduction section 97.

The second supply pipe 92 sends the heated steam supplied from the sub-steam supply unit 98 to the heated steam introduction unit 97. The second supply pipe 92 is a pipe that connects the sub steam supply unit 98 and the first supply pipe 91. One end of the second supply pipe 92 is connected in the middle of the first supply pipe 91 so as to join the first supply pipe 91. The other end of the second supply pipe 92 is connected to the sub steam supply unit 98.

The third supply pipe 93 sends a part of the steam supplied from the main steam supply unit 8 to the storage unit 99. The third supply pipe 93 is a pipe that connects the main steam pipe 81 and the storage unit 99. One end of the third supply pipe 93 is connected to the main steam pipe 81 so as to branch from the main steam pipe 81 at a position closer to the steam supply source than the first supply pipe 91. The other end of the third supply pipe 93 is connected to the storage unit 99.

The fourth supply pipe 94 sends the heated steam supplied from the storage unit 99 to the heated steam introduction unit 97. The fourth supply pipe 94 is a pipe that connects the storage unit 99 and the first supply pipe 91. One end of the fourth supply pipe 94 is connected to the storage unit 99. The other end of the fourth supply pipe 94 is connected to the first supply pipe 91 so as to join the first supply pipe 91 at the same position as the second supply pipe 92.

The fifth supply pipe 95 is a pipe that connects the first supply pipe 91 and the fourth supply pipe 94. One end of the fifth supply pipe 95 is connected to the main steam pipe 81 so as to branch from the main steam pipe 81 between the first supply pipe 91 and the third supply pipe 93. The other end of the fifth supply pipe 95 is connected in the middle of the fourth supply pipe 94 so as to join the fourth supply pipe 94.

The first valve portion 101 makes it possible to adjust the flow state of the steam flowing through the first supply pipe 91. The first valve portion 101 is provided in the middle of the first supply pipe 91. Specifically, the first valve portion 101 is attached to the first supply pipe 91 between the connection position with the second supply pipe 92 and the connection position with the main steam pipe 81. The first valve portion 101 is opened or closed in response to a signal from the control unit 200, which will be described later. As the first valve portion 101, for example, an electromagnetic valve is used.

The second valve portion 102 makes it possible to adjust the flow state of the steam flowing through the second supply pipe 92. The second valve portion 102 is provided in the middle of the second supply pipe 92. The second valve portion 102 is opened or closed in response to a signal from the control unit 200 described later. As the second valve portion 102, for example, a solenoid valve is used.

The third valve portion 103 makes it possible to adjust the flow state of the steam flowing through the third supply pipe 93. The third valve portion 103 is provided in the middle of the third supply pipe 93. The third valve unit 103 is opened or closed in response to a signal from the control unit 200, which will be described later. As the third valve portion 103, for example, an electromagnetic valve is used.

The fourth valve portion 104 makes it possible to adjust the flow state of the steam flowing through the fourth supply pipe 94. The fourth valve portion 104 is provided in the middle of the fourth supply pipe 94. The fourth valve unit 104 is a solenoid valve that is opened or closed in response to a signal from the control unit 200, which will be described later. As the fourth valve portion 104, for example, a solenoid valve is used.

The fifth valve portion 105 makes it possible to adjust the flow state of the steam flowing through the fifth supply pipe 95. The fifth valve portion 105 is provided in the middle of the fifth supply pipe 95. The fifth valve portion 105 is opened or closed in response to a signal from the control unit 200 described later. As the fifth valve portion 10, for example, a solenoid valve is used.

The temperature measuring unit 100 measures the temperature of the steam supplied from the main steam supply unit 8 to the first main flow path 31. The temperature measuring unit 100 is attached to the main steam pipe 81 on the connection portion side with the first supply pipe 91 rather than the main steam valve unit 82. The temperature measuring unit 100 is capable of measuring the temperature of steam by circulating steam through the main steam pipe 81. The temperature measuring unit 100 sends the measured steam temperature information to the control unit 200.

The control unit 200 controls the supply state of the heated steam. As a result, the control unit 200 controls the heating state of the inner casing 3 by the inner casing heating unit 9. The control unit 200 of the present embodiment controls the supply state of the heated steam to the heated steam introduction unit 97. The control unit 200 controls not only the supply state of the heated steam to the heated steam introduction unit 97 but also the supply state of the steam to the outer introduction port 52. Specifically, the control unit 200 supplies the heated steam from the sub-steam supply unit 98 to the heated steam introduction unit 97 without supplying the steam to the outer introduction port 52 before starting. The control unit 200 supplies steam from the main steam supply unit 8 to the outer introduction port 52 while supplying the heated steam to the heated steam introduction unit 97 until the initial stage of activation. During the rated operation, the control unit 200 supplies steam from the main steam supply unit 8 to the outer introduction port 52 without supplying the heated steam to the heated steam introduction unit 97. The control unit 200 supplies the heated steam from the storage unit 99 to the heated steam introduction unit 97 at the time of stoppage or emergency.

The control unit 200 controls the adjustment of the supply state of the steam and the heated steam by opening or closing the first valve portion 101 to the fifth valve portion 105. The control unit 200 includes an input unit 201, a determination unit 202, a main steam valve output unit 203, a first valve output unit 204, a second valve output unit 205, a third valve output unit 206, and a fourth valve. It has an output unit 207 and a fifth valve output unit 208.

Here, before the start-up, after the operation signal for starting the operation of the steam turbine 1 is input by the operator operating the operation panel or the like, the steam starts to flow into the first main flow path 31. It is the previous state. Before the start, the operation of the steam turbine 1 is started, but the rotor 2 is not rotating, and the first main flow path 31 and the second main flow path 51 are in a vacuum state. Before starting, the steam turbine 1 is in a state of preparing to receive steam.

Further, the initial start-up is a predetermined predetermined condition in which it can be considered that the clearance between the inner casing 3 and the rotor 2 is secured after the steam supplied from the main steam supply unit 8 starts to flow into the first main flow path 31. Is satisfied. Therefore, the control unit 200 supplies the heated steam to the heated steam introduction unit 97 until the specified condition is satisfied after the steam starts to flow into the first main flow path 31.

The specified conditions are sufficiently widened so that the distance between the inner peripheral surface 3a of the inner casing 3 and the tip of the moving blade 22 and the distance between the tip of the stationary blade 4 and the outer peripheral surface 2a of the rotor body 21 can be regarded as not contacting. It is a condition that can be said to be in a state of being. Therefore, when the specified conditions are satisfied, it can be considered that the inner casing 3 and the moving blade 22 do not come into contact with each other, and the stationary blade 4 and the rotor main body 21 do not come into contact with each other. The specified conditions of the present embodiment include, for example, the ratio of the output of the steam turbine 1 to the rated output. More specifically, as a specified condition, for example, a predetermined time that can be regarded as 10% to 40% of the rated output of the steam turbine 1 can be mentioned.

The condition is not limited to using time. The specified conditions may be used by directly measuring the output by another means such as measuring the pressure of the steam discharged from the outer discharge port 53.

Further, at the time of stoppage and emergency, steam cannot be supplied from the steam supply unit to the first main flow path 31. When stopped, it is after the operation signal for stopping the operation of the steam turbine 1 is input, and when the steam turbine 1 is stopped, the output of the steam turbine 1 is below the specified value. An emergency is a state in which a trip signal is issued due to some trouble and an emergency stop is performed.

The temperature information measured by the temperature measuring unit 100 is input to the input unit 201. An operation signal is input to the input unit 201 from an operation panel (not shown) operated by an operator when operating the steam turbine 1. A trip signal is input to the input unit 201 from the outside. The input unit 201 outputs the input temperature information, operation signal, and trip signal to the determination unit 202.

The determination unit 202 determines the main steam valve unit 82, the first valve unit 101, the second valve unit 102, the third valve unit 103, and the fourth valve unit 104 based on the input temperature information, operation signal, and trip signal. , And outputs a signal to open or close the fifth valve portion 105. The determination unit 202 outputs a signal for opening or closing the main steam valve unit 82 to the main steam valve output unit 203. The determination unit 202 outputs a signal for opening or closing the first valve unit 101 to the first valve output unit 204. The determination unit 202 outputs a signal for opening or closing the second valve unit 102 to the second valve output unit 205. The determination unit 202 outputs a signal for opening or closing the third valve unit 103 to the third valve output unit 206. The determination unit 202 outputs a signal for opening or closing the fourth valve unit 104 to the fourth valve output unit 207. The determination unit 202 outputs a signal for opening or closing the fifth valve unit 105 to the fifth valve output unit 208.

Specifically, the determination unit 202 determines whether or not an operation signal for starting the operation of the steam turbine 1 has been input. When the determination unit 202 determines that the operation signal for starting the operation of the steam turbine 1 has been input, the main steam valve unit 82, the first valve unit 101, the third valve unit 103, the fourth valve unit 104, and the fifth valve unit 202. A signal for closing the valve portion 105 is output. When the determination unit 202 determines that the operation signal for starting the operation of the steam turbine 1 has been input, the determination unit 202 outputs a signal for opening the second valve unit 102.

The determination unit 202 determines whether or not the temperature measurement unit 100 starts measuring the temperature of the steam and the temperature information is input. When the determination unit 202 determines that the temperature information has been input, it outputs a signal for opening the main steam valve unit 82, the second valve unit 102, the third valve unit 103, and the fifth valve unit 105. When the determination unit 202 determines that the temperature information has been input, the determination unit 202 outputs a signal for closing the first valve unit 101 and the fourth valve unit 104.

The determination unit 202 determines whether or not the input temperature information satisfies the reference value. The reference value of the present embodiment is a value of the temperature of the heated steam supplied from the sub-steam supply unit 98. Therefore, the determination unit 202 determines whether or not the temperature of the steam supplied to the first main flow path 31 exceeds the temperature of the heated steam. When the determination unit 202 determines that the temperature information exceeds the reference value, the determination unit 202 outputs a signal for opening the main steam valve unit 82, the first valve unit 101, the third valve unit 103, and the fifth valve unit 105. When the determination unit 202 determines that the temperature information exceeds the reference value, the determination unit 202 outputs a signal for closing the second valve unit 102 and the fourth valve unit 104.

The determination unit 202 determines whether or not a predetermined time that can be considered that the output of the steam turbine 1 has reached 10% to 40% of the rated output has elapsed. When the determination unit 202 determines that the predetermined time has been exceeded since the operation signal for starting the operation of the steam turbine 1 is input, the determination unit 202 opens the main steam valve unit 82, the third valve unit 103, and the fifth valve unit 105. Output a signal. When the determination unit 202 determines that the predetermined time has been exceeded, the determination unit 202 outputs a signal for closing the first valve unit 101, the second valve unit 102, and the fourth valve unit 104.

The determination unit 202 determines whether or not an operation signal for stopping the operation of the steam turbine 1 has been input. When the determination unit 202 determines that the operation signal for stopping the operation of the steam turbine 1 has been input, the main steam valve unit 82, the first valve unit 101, the second valve unit 102, the third valve unit 103, and the fifth valve unit 202. A signal for closing the valve portion 105 is output. When the determination unit 202 determines that the operation signal for stopping the operation of the steam turbine 1 has been input, the determination unit 202 outputs a signal for opening the fourth valve unit 104.

The determination unit 202 determines whether or not a trip signal has been input. When the determination unit 202 determines that the trip signal has been input, the determination unit 202 outputs a signal for closing the main steam valve unit 82, the first valve unit 101, the second valve unit 102, the third valve unit 103, and the fifth valve unit 105. To do. When the determination unit 202 determines that the trip signal has been input, the determination unit 202 outputs a signal for opening the fourth valve unit 104.

The main steam valve output unit 203 receives a signal for opening or closing the main steam valve unit 82 from the determination unit 202. The main steam valve output unit 203 opens or closes the main steam valve unit 82 based on the input signal.

A signal for opening or closing the first valve unit 101 is input from the determination unit 202 to the first valve output unit 204. The first valve output unit 204 opens or closes the first valve unit 101 based on the input signal.

The second valve output unit 205 receives a signal for opening or closing the second valve unit 102 from the determination unit 202. The second valve output unit 205 opens or closes the second valve unit 102 based on the input signal.

A signal for opening or closing the third valve unit 103 is input from the determination unit 202 to the third valve output unit 206. The third valve output unit 206 opens or closes the third valve unit 103 based on the input signal.

A signal for opening or closing the fourth valve unit 104 is input from the determination unit 202 to the fourth valve output unit 207. The fourth valve output unit 207 opens or closes the fourth valve unit 104 based on the input signal.

A signal for opening or closing the fifth valve unit 105 is input from the determination unit 202 to the fifth valve output unit 208. The fifth valve output unit 208 opens or closes the fifth valve unit 105 based on the input signal.

In such a steam turbine 1, the operation panel is operated in order to start the operation from a completely stopped state. As a result, the steam turbine 1 is in the state before starting, and an operation signal for starting the operation of the steam turbine 1 is input to the determination unit 202 via the input unit 201. The determination unit 202 determines that an operation signal for starting the operation of the steam turbine 1 has been input.

As a result, a signal for closing the main steam valve unit 82 is input from the determination unit 202 to the main steam valve output unit 203. A signal for closing the first valve unit 101 is input from the determination unit 202 to the first valve output unit 204. A signal for opening the second valve unit 102 is input from the determination unit 202 to the second valve output unit 205. A signal for closing the third valve unit 103 is input from the determination unit 202 to the third valve output unit 206. A signal for closing the fourth valve unit 104 is input from the determination unit 202 to the fourth valve output unit 207. A signal for closing the fifth valve unit 105 is input from the determination unit 202 to the fifth valve output unit 208.

As a result, the main steam valve portion 82, the first valve portion 101, the third valve portion 103, the fourth valve portion 104, and the fifth valve portion 105 are closed. Since the main steam valve portion 82 is closed, the flow of steam from the main steam pipe 81 to the outer introduction port 52 is blocked, and steam does not flow into the first main flow path 31. Similarly, the flow of steam in the first supply pipe 91, the third supply pipe 93, the fourth supply pipe 94, and the fifth supply pipe 95 is cut off. On the other hand, by opening only the second valve portion 102, the flow of steam in the second supply pipe 92 is opened. Therefore, the heated steam supplied from the sub-steam supply unit 98 flows through the second supply pipe 92 and is sent to the heated steam introduction unit 97. As a result, the heated steam flows into the second main flow path 51. The heated steam flowing through the second main flow path 51 is discharged to the outside from the outer discharge port 53.

By supplying the heated steam to the second main flow path 51 before the steam flows through the first main flow path 31, the heated steam flows through the second main flow path 51. The outer peripheral surface 3b of the inner casing 3 is heated by this heated steam. As a result, the inner casing 3 expands due to the heat of the heated steam. On the other hand, since steam does not flow through the first main flow path 31, the rotor body 21 and the rotor blades 22 hardly expand due to heat. As a result, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and the clearance between the tip of the stationary blade 4 and the outer peripheral surface 2a of the rotor main body 21 are increased.

After that, when the steam supplied from the supply source reaches the temperature measuring unit 100, the temperature measuring unit 100 starts measuring the temperature of the steam. When the temperature measuring unit 100 starts measuring the temperature of the steam, the temperature information is input to the determination unit 202 via the input unit 201. The determination unit 202 determines that the temperature information has been input. In addition to the above conditions, the following operations are started after the start conditions on the plant side are met.

As a result, a signal for opening the main steam valve unit 82 is input from the determination unit 202 to the main steam valve output unit 203. A signal for closing the first valve unit 101 is input from the determination unit 202 to the first valve output unit 204. A signal for opening the second valve unit 102 is input from the determination unit 202 to the second valve output unit 205. A signal for opening the third valve unit 103 is input from the determination unit 202 to the third valve output unit 206. A signal for closing the fourth valve unit 104 is input from the determination unit 202 to the fourth valve output unit 207. A signal for opening the fifth valve unit 105 is input from the determination unit 202 to the fifth valve output unit 208.

As a result, in addition to the second valve portion 102, the main steam valve portion 82, the third valve portion 103, and the fifth valve portion 105 are newly opened. Since the main steam valve portion 82 is open, steam is supplied to the outer introduction port 52 via the main steam pipe 81. The steam supplied to the outer introduction port 52 flows into the first main flow path 31 through the inner introduction port 32. The steam flowing into the first main flow path 31 reaches the inner discharge port 33 while rotating the rotor 2 and gradually lowering the temperature. The steam that has reached the inner discharge port 33 flows into the second main flow path 51.

Further, since the second valve portion 102 remains open, the heated steam supplied from the sub steam supply portion 98 flows through the second supply pipe 92 and flows into the second main flow path 51 from the heated steam introduction portion 97. Continue to do. The heated steam flowing into the second main flow path 51 merges with the steam flowing through the first main flow path 31. The combined heated steam and steam flow through the second main flow path 51 and are discharged to the outside from the outer discharge port 53.

By supplying the heated steam to the second main flow path 51, the outer peripheral surface 3b of the inner casing 3 is heated at a temperature higher than that of the steam flowing through the first main flow path 31. As a result, the inner casing 3 expands faster than when exposed only to the steam flowing through the first main flow path 31. As a result, the inner casing 3 expands faster than the rotor blades 22 and the rotor body 21. Therefore, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and the clearance between the tip of the stationary blade 4 and the outer peripheral surface 2a of the rotor main body 21 are not narrowed.

Further, since the third valve portion 103 and the fifth valve portion 105 are opened, a part of the steam flowing through the main steam pipe 81 via the third supply pipe 93 and the fifth supply pipe 95 is stored. Supplied to 99. In the storage unit 99, the supplied steam is stored. Therefore, while the steam flows from the main steam supply unit 8 into the first main flow path 31, a part of the steam continues to be stored in the storage unit 99.

Next, as the output of the steam turbine 1 approaches the rated output, the temperature of the steam supplied to the outer introduction port 52 via the main steam pipe 81 gradually rises. As the temperature of the steam rises, the value of the temperature information measured by the temperature measuring unit 100 and input to the input unit 201 rises. As a result, the determination unit 202 determines that the input temperature information exceeds the temperature of the heated steam supplied from the sub-steam supply unit 98.

As a result, a signal for opening the main steam valve unit 82 is input from the determination unit 202 to the main steam valve output unit 203. A signal for opening the first valve unit 101 is input from the determination unit 202 to the first valve output unit 204. A signal for closing the second valve unit 102 is input from the determination unit 202 to the second valve output unit 205. A signal for opening the third valve unit 103 is input from the determination unit 202 to the third valve output unit 206. A signal for closing the fourth valve unit 104 is input from the determination unit 202 to the fourth valve output unit 207. A signal for opening the fifth valve unit 105 is input from the determination unit 202 to the fifth valve output unit 208.

As a result, the opened second valve portion 102 is closed, and the first valve portion 101 is newly opened. When the first valve portion 101 is opened, a part of the steam flowing through the main steam pipe 81 via the first supply pipe 91 is supplied to the heated steam introduction portion 97 as heated steam. The heated steam supplied to the heated steam introduction unit 97 flows into the second main flow path 51 and merges with the steam flowing through the first main flow path 31.

On the other hand, since the second valve portion 102 is closed, the flow of steam in the second supply pipe 92 is cut off. Therefore, the supply of the heated steam from the sub-steam supply unit 98 to the heated steam introduction unit 97 is stopped.

Therefore, the steam having a higher temperature than the heated steam supplied from the sub-steam supply unit 98 and not flowing through the first main flow path 31 is supplied to the second main flow path 51 as heated steam. Therefore, the outer peripheral surface 3b of the inner casing 3 is heated at a temperature higher than the steam flowing through the first main flow path 31 and the heated steam supplied from the sub-steam supply unit 98. As a result, the inner casing 3 expands as compared with the case where it is exposed only to the steam flowing through the first main flow path 31 or the case where it is exposed to the heated steam supplied from the sub steam supply unit 98. As a result, even if the temperature of the steam flowing into the first main flow path 31 rises, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and the tip of the stationary blade 4 and the rotor main body 21 The clearance between the outer peripheral surface 2a and the outer peripheral surface 2a is secured without being narrowed.

After that, when a predetermined time elapses from the start of operation of the steam turbine 1, the output of the steam turbine 1 reaches 10% to 40% of the rated output. Therefore, the determination unit 202 determines that the predetermined time has been exceeded after the operation signal for starting the operation of the steam turbine 1 is input.

As a result, a signal for opening the main steam valve unit 82 is input from the determination unit 202 to the main steam valve output unit 203. A signal for closing the first valve unit 101 is input from the determination unit 202 to the first valve output unit 204. A signal for closing the second valve unit 102 is input from the determination unit 202 to the second valve output unit 205. A signal for opening the third valve unit 103 is input from the determination unit 202 to the third valve output unit 206. A signal for closing the fourth valve unit 104 is input from the determination unit 202 to the fourth valve output unit 207. A signal for opening the fifth valve unit 105 is input from the determination unit 202 to the fifth valve output unit 208.

As a result, the first valve portion 101 is newly closed. Since the first valve portion 101 is closed, a part of the steam flowing through the main steam pipe 81 is not supplied to the heated steam introduction portion 97. As a result, the inflow of the heated steam from the heated steam introduction unit 97 to the second main flow path 51 is stopped. Therefore, the heating of the inner casing 3 by the heating steam is stopped. Therefore, all the steam flowing through the main steam pipe 81 is used to operate the steam turbine 1. As a result, the steam turbine 1 can be operated efficiently.

In addition, the operation panel is operated to stop the operation of the steam turbine 1. As a result, an operation signal for stopping the operation of the steam turbine 1 is input to the determination unit 202 via the input unit 201. The determination unit 202 determines that an operation signal for stopping the operation of the steam turbine 1 has been input.

As a result, a signal for closing the main steam valve unit 82 is input from the determination unit 202 to the main steam valve output unit 203. A signal for closing the first valve unit 101 is input from the determination unit 202 to the first valve output unit 204. A signal for closing the second valve unit 102 is input from the determination unit 202 to the second valve output unit 205. A signal for closing the third valve unit 103 is input from the determination unit 202 to the third valve output unit 206. A signal for opening the fourth valve unit 104 is input from the determination unit 202 to the fourth valve output unit 207. A signal for closing the fifth valve unit 105 is input from the determination unit 202 to the fifth valve output unit 208.

As a result, the main steam valve portion 82, the third valve portion 103, and the fifth valve portion 105 are closed, and the fourth valve portion 104 is newly opened. When the fourth valve portion 104 is opened, the steam stored in the storage portion 99 flows through the fourth supply pipe 94 and flows into the second main flow path 51 from the heated steam introduction portion 97 as heated steam.

Heated steam is supplied to the second main flow path 51 in a situation where steam is not flowing through the first main flow path 31. As a result, the outer peripheral surface 3b of the inner casing 3 is heated, and the inner casing 3 expands due to the heat of the heated steam. On the other hand, since steam does not flow through the first main flow path 31, the rotor body 21 and the moving blades 22 begin to contract. As a result, a clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and a clearance between the tip of the stationary blade 4 and the outer peripheral surface of the rotor main body 21 are secured.

Further, even when the operation of the steam turbine 1 is urgently stopped and an emergency occurs, the steam stored in the storage unit 99 flows through the fourth supply pipe 94 and is heated as heated steam as in the case of the stop. It flows from the steam introduction section 97 into the second main flow path 51.

According to the steam turbine 1 of the first embodiment as described above, a part of the steam flowing through the main steam pipe 81 is supplied as heated steam to the heated steam introduction unit 97 via the first supply pipe 91. .. Therefore, the outer peripheral surface 3b of the inner casing 3 is heated by the heated steam flowing into the second main flow path 51. Therefore, in the inner casing 3, not only the inner peripheral surface 3a is heated by the steam flowing through the first main flow path 31, but also the outer peripheral surface 3b is heated by the heated steam flowing through the second main flow path 51. As a result, the inner casing 3 can be expanded faster than the rotor blades 22 and the rotor body 21 that are exposed only to the steam flowing through the first main flow path 31. As a result, a clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and a clearance between the tip of the stationary blade 4 and the outer peripheral surface 2a of the rotor main body 21 are secured.

In particular, when the steam turbine 1 is stopped once, the temperature of the outer casing 5 and the inner casing 3 is sufficiently lowered, but the temperature of the rotor 2 is not sufficiently lowered. When the steam turbine 1 is restarted in such a state, the rotor blades 22 that rotate while being exposed to the high-temperature steam flowing through the first main flow path 31 expand more than the inner casing 3 due to centrifugal force and thermal elongation. Resulting in. Therefore, when restarting, the distance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 becomes small, and there is a possibility that they come into contact with each other. However, when steam is supplied to the first main flow path 31, a part of this steam is supplied to the inner casing 3 as heating steam and heated, so that the inner casing 3 is expanded faster than the moving blades 22. Can be done. Therefore, it is possible to prevent the distance between the tip of the rotor blade 22 and the inner peripheral surface 3a of the inner casing 3 from being narrowed.

Therefore, depending on the operating condition of the steam turbine 1, the tip of the moving blade 22 may come into contact with the inner peripheral surface 3a of the inner casing 3, or the tip of the stationary blade 4 may come into contact with the outer peripheral surface 2a of the rotor body 21. Can be prevented. Therefore, it is not necessary to take a large clearance in advance between the rotor 2 side and the inner casing 3 side, and an appropriate value can be set.

Further, since the heated steam is supplied from the sub-steam supply unit 98 to the second main flow path 51 before the start-up, the heated steam flows to the second main flow path 51 before the steam is supplied to the first main flow path 31. .. Therefore, the inner casing 3 is heated and expanded by the heated steam flowing through the second main flow path 51 before the rotor blade 22 is exposed to the steam flowing through the first main flow path 31 and expands. As a result, the clearance between the tip of the rotor blade 22 and the inner peripheral surface 3a of the inner casing 3 can be widened with high accuracy before starting. Therefore, it is possible to prevent the tip of the moving blade 22 from coming into contact with the inner peripheral surface 3a of the inner casing 3 or the tip of the stationary blade 4 from coming into contact with the outer peripheral surface 2a of the rotor body 21 with high accuracy. ..

Further, by supplying the heated steam to the second main flow path 51, the heated steam that heats the inner casing 3 together with the steam flowing through the first main flow path 31 directs the second main flow path 51 toward the outer discharge port 53. It flows. Therefore, the heated steam is discharged to the outside of the steam turbine 1 from the outer discharge port 53 together with the steam flowing through the first main flow path 31. Therefore, it is not necessary to newly provide the steam turbine 1 with a structure for discharging heated steam. As a result, the inner casing heating unit 9 that heats the inner casing 3 by utilizing a part of the steam supplied from the main steam supply unit 8 can be formed with a simple configuration.

Further, the heated steam is continuously supplied from the sub-steam supply unit 98 until the temperature of the steam flowing through the main steam pipe 81 becomes higher than the temperature of the heated steam supplied from the sub-steam supply unit 98. Therefore, even when the temperature of the steam flowing through the main steam pipe 81 is not sufficiently high as immediately after the start of operation, the inner casing 3 can be stably heated.

Further, by supplying the heated steam to the second main flow path 51 until the initial stage of activation satisfying the specified condition, the inner casing 3 continues to be heated until it can be considered that the inner casing 3 and the moving blades 22 do not contact each other. Specifically, the inner casing 3 continues to be heated until it reaches 10% to 40% of the rated output of the steam turbine 1. As a result, it is possible to prevent the tip of the rotor blade 22 from coming into contact with the inner peripheral surface 3a of the inner casing 3 due to a narrow distance with high accuracy.

Further, a part of the steam is stored in the storage unit 99 while the steam is continuously supplied to the first main flow path 31 through the main steam pipe 81. Therefore, when the supply of steam to the first main flow path 31 is stopped as in the case of a stop or an emergency, the inner casing 3 is heated by the heated steam and expands. As a result, it is possible to prevent the inner casing 3 from being cooled before the moving blades 22 and narrowing the distance between the tip of the moving blades 22 and the inner peripheral surface 3a of the inner casing 3.

In the present embodiment, the heated steam is supplied from the sub-steam supply unit 98 before the start-up, but the configuration is not limited to this. For example, when steam is already stored in the storage unit 99 as in the case of restarting, heated steam may be supplied from the storage unit 99 before starting up instead of the sub-steam supply unit 98. Further, in the present embodiment, the heated steam is supplied from the storage unit 99 at the time of stoppage or emergency, but the present invention is not limited to such a configuration. If the sub-steam supply unit 98 can be operated at the time of stoppage or emergency, heated steam may be supplied from the sub-steam supply unit 98 instead of the storage unit 99.

<< Second Embodiment >>
Next, a second embodiment of the steam turbine of the present invention will be described. In the steam turbine shown in the second embodiment, the inner casing heating portion is partially different. Therefore, in the description of the second embodiment, the same parts as those of the first embodiment are designated by the same reference numerals, and duplicate description will be omitted. That is, the description of the steam turbine configuration common to the configuration described in the first embodiment will be omitted.

In the inner casing heating unit 9A of the second embodiment, the heated steam is not supplied to the second main flow path 51. In the inner casing heating unit 9A, as shown in FIG. 2, heated steam is circulated inside the inner casing 3. Specifically, the inner casing heating unit 9A has a first internal flow path portion 301, a second internal flow path portion 302, a third internal flow path portion 303, and a heated steam discharge portion 304. ..

The first internal flow path portion 301 supplies heated steam from the heated steam introduction portion 97 to the inside of the inner casing 3. The first internal flow path portion 301 is a pipe that connects the inner peripheral surface 5a of the outer casing 5 and the outer peripheral surface 3b of the inner casing 3. The first internal flow path portion 301 is connected to the opening of the inner peripheral surface 5a of the outer casing 5 of the heated steam introduction portion 97. The first internal flow path portion 301 is connected to the outer peripheral surface 3b of the inner casing 3 at a position close to the inner discharge port 33 in the axial direction Da. It is preferable that the first internal flow path portion 301 is connected at a position facing the other side of the outermost peripheral surface 3b of the inner casing 3 in the axial direction Da.

The second internal flow path portion 302 extends inside the inner casing 3 in the axial direction Da. The second internal flow path portion 302 is a through hole that opens in the outer peripheral surface 3b at a position separated from the axial direction Da. One opening of the second internal flow path portion 302 in the axial direction Da is connected to the first internal flow path portion 301. The other opening of the second internal flow path portion 302 in the axial direction Da is connected to the third internal flow path portion 303.

The third inner flow path portion 303 supplies the heated steam flowing through the inside of the inner casing 3 to the outer casing 5. The third internal flow path portion 303 is a pipe that connects the inner peripheral surface 5a of the outer casing 5 and the outer peripheral surface 3b of the inner casing 3. The third internal flow path portion 303 connects the heated steam discharge portion 304 and the second internal flow path portion 302.

The heated steam discharge unit 304 is a discharge port that discharges the heated steam to the outside of the outer casing 5. The heated steam discharge unit 304 is formed in the outer casing 5. The heated steam discharge unit 304 is connected to the third internal flow path unit 303. The heated steam discharge unit 304 of the present embodiment is formed on the other side in the axial direction Da from the heated steam introduction unit 97. The heated steam discharge unit 304 is a through hole that communicates with the inside and the outside of the outer casing 5.

According to the steam turbine 1A of the second embodiment as described above, the heated steam supplied to the heated steam introduction unit 97 flows into the second internal flow path portion 302 via the first internal flow path portion 301. The heated steam flowing through the second internal flow path portion 302 is discharged to the outside from the heated steam discharge section 304 via the third internal flow path portion 303.

By flowing through the second internal flow path portion 302, the heated steam circulates inside the inner casing 3. Therefore, the position closer to the inner peripheral surface 3a of the inner casing 3 is heated as compared with the case where the heated steam is circulated in the second main flow path 51. As a result, the region of the inner casing 3 close to the inner peripheral surface 3a can be heated to expand the inner casing 3. As a result, the inner casing 3 can be expanded faster than the rotor blades 22 and the rotor body 21. As a result, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and the clearance between the tip of the stationary blade 4 and the outer peripheral surface 2a of the rotor main body 21 are ensured with high accuracy.

<< Third Embodiment >>
Next, a third embodiment of the steam turbine according to the present invention will be described. In the third embodiment described below, the inner casing heating portion is partially different. Therefore, in the description of the third embodiment, the same parts as those of the first embodiment and the second embodiment are designated by the same reference numerals, and duplicate description will be omitted. That is, the description of the steam turbine configuration common to the configurations described in the first embodiment and the second embodiment will be omitted.

In the inner casing heating unit 9B of the third embodiment, the heated steam is brought into direct contact with the outer peripheral surface 3b of the inner casing 3 without supplying steam to the second main flow path 51. That is, the inner casing heating unit 9B of the third embodiment brings the heated steam into contact with the outer peripheral surface 3b of the inner casing 3 without merging with the steam flowing through the second main flow path 51. As shown in FIG. 3, the inner casing heating unit 9B has a steam flow unit 401, a steam branch pipe 402, a steam confluence pipe 403, and a heated steam discharge unit 404.

The steam flow unit 401 circulates heated steam in the circumferential direction Dc along the outer peripheral surface 3b of the inner casing 3. The steam flow unit 401 forms an annular shape and is attached to the outer peripheral surface 3b of the inner casing 3. A plurality of steam flow units 401 (three in the present embodiment) are arranged with respect to the outer peripheral surface 3b of the inner casing 3 at intervals in the axial direction Da.

The steam branch pipe 402 branches the heated steam supplied from the heated steam introduction unit 97 and supplies the heated steam to a plurality of steam flow units 401, respectively. The steam branch pipe 402 is a pipe that connects the inner peripheral surface 5a of the outer casing 5 and the steam flow unit 401. The steam branch pipe 402 is connected to the opening of the inner peripheral surface 5a of the outer casing 5 of the heated steam introduction portion 97.

The steam merging pipe 403 merges the heated steam that has flowed through the steam flow section 401 and supplies it to the outer casing 5. The steam merging pipe 403 is a pipe that connects the inner peripheral surface 5a of the outer casing 5 and the inner peripheral surface 5a of the outer casing 5.

The heated steam discharge unit 404 is a discharge port that discharges the heated steam to the outside of the outer casing 5. The heated steam discharge unit 404 is formed in the outer casing 5. The heated steam discharge unit 404 is connected to the steam merging pipe 403. The heated steam discharge unit 404 of the third embodiment has the same position in the axial direction Da as the heated steam introduction unit 97, and is formed at a position 180 ° away from the circumferential direction Dc. Therefore, for example, the heated steam discharge unit 404 is one of the heated steam introduction units 97 in the first embodiment and the second embodiment, and is a through hole that communicates with the inside and the outside of the outer casing 5.

According to the steam turbine 1B of the third embodiment as described above, the heated steam supplied to the heated steam introduction unit 97 flows into the plurality of steam flow units 401 via the steam branch pipe 402, respectively. In the steam flow section 401, the heated steam flows in the circumferential direction Dc while directly contacting the outer peripheral surface 3b of the inner casing 3. The heated steam flowing through the steam flow unit 401 is merged by the steam merging pipe 403 and discharged to the outside from the heated steam discharge unit 404.

As the heated steam flows through the steam flow unit 401, the heated steam comes into contact with the outer peripheral surface 3b of the inner casing 3 without merging with the steam flowing through the second main flow path 51. Therefore, it is possible to prevent the temperature of the heated steam from being lowered by the steam flowing through the second main flow path 51. As a result, the outer peripheral surface 3b of the inner casing 3 can be heated and expanded with the heated steam at a higher temperature. As a result, the inner casing 3 can be expanded faster than the rotor blades 22 and the rotor body 21. As a result, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and the clearance between the tip of the stationary blade 4 and the outer peripheral surface of the rotor main body 21 are ensured with high accuracy.

The heated steam supplied to the plurality of steam flow units 401 is not limited to the same as in the present embodiment. For example, the temperature of the heated steam supplied by the plurality of steam flow units 401 may be changed. Specifically, the temperature of the heated steam supplied to the steam flow unit 401 arranged on the other side of the axial direction Da is the heating supplied to the steam flow unit 401 arranged on one side of the axial direction Da. It may be lower than the temperature of the steam. At this time, the temperature of the heated steam may be adjusted so that the temperature gradually decreases toward the other side in the axial direction Da.

<< Fourth Embodiment >>
Next, a fourth embodiment of the steam turbine according to the present invention will be described. In the fourth embodiment described below, the inner casing heating portion is partially different. Therefore, in the description of the fourth embodiment, the same parts as those of the first to third embodiments are designated by the same reference numerals, and duplicate description will be omitted. That is, the description of the configuration of the steam turbine common to the configurations described in the first to third embodiments will be omitted.

In the inner casing heating unit 9C of the fourth embodiment, heated steam is directly injected into the outer peripheral surface 3b of the inner casing 3 to bring them into contact with each other. In the inner casing heating unit 9C, the heated steam after injection is merged with the steam flowing through the second main flow path 51. As shown in FIG. 4, the inner casing heating unit 9C has a steam injection unit 501 and an injection unit connecting pipe 502.

The steam injection section 501 injects heated steam toward the outer peripheral surface 3b of the inner casing 3. The steam injection section 501 of the present embodiment has a tubular shape with both sides open in the axial direction Da. The steam injection unit 501 is formed with a space between the inner peripheral surface and the outer peripheral surface thereof so that heated steam can flow in the circumferential direction Dc. The steam injection section 501 covers the inner casing 3 from the outside of the radial Dr. The steam injection section 501 is formed so as to correspond to the length of the outer peripheral surface 3b of the inner casing 3 in the axial direction Da. The steam injection section 501 is formed with a plurality of injection holes on the surface of the inner casing 3 facing the outer peripheral surface 3b. A plurality of injection holes are formed so as to be separated from each other in the axial direction Da and the circumferential direction Dc. Therefore, the heated steam flowing in the circumferential direction Dc inside the steam injection unit 501 is injected from the injection hole toward the outer peripheral surface 3b of the inner casing 3.

The injection unit connecting pipe 502 supplies the heated steam supplied from the heated steam introduction unit 97 to the steam injection unit 501. The injection unit connecting pipe 502 is a pipe that connects the inner peripheral surface 5a of the outer casing 5 and the steam injection unit 501. The injection section connecting pipe 502 extends from the heated steam introduction section 97 toward the inside of the radial Dr.

According to the steam turbine 1C of the fourth embodiment as described above, the heated steam supplied to the heated steam introduction section 97 flows into the inside of the steam injection section 501 via the injection section connecting pipe 502. The heated steam flowing in the circumferential direction Dc in the steam injection unit 501 is injected from the injection hole toward the outer peripheral surface 3b of the inner casing 3. The injected heated steam joins the second main flow path 51 through the openings on both sides in the axial direction Da. The combined heated steam and steam flow through the second main flow path 51 and are discharged to the outside from the outer discharge port 53.

In the steam turbine 1C, the heated steam is injected toward the outer peripheral surface 3b of the inner casing 3 without merging with the steam flowing through the second main flow path 51. Therefore, the heated steam can be brought into contact with the outer peripheral surface 3b of the inner casing 3 before the temperature of the heated steam is lowered by the steam flowing through the second main flow path 51. In addition, a high heat transfer effect can be obtained. As a result, the outer peripheral surface 3b of the inner casing 3 can be heated and expanded with the heated steam at a higher temperature. As a result, the inner casing 3 can be expanded faster than the rotor blades 22 and the rotor body 21. As a result, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and the clearance between the tip of the stationary blade 4 and the outer peripheral surface 2a of the rotor main body 21 are ensured with high accuracy.

Further, the steam injection section 501 has a tubular shape with both sides open in the axial direction Da. Therefore, the heated steam injected toward the outer peripheral surface 3b of the inner casing 3 joins the second main flow path 51 from the openings on both sides in the axial direction Da. Therefore, the heated steam is discharged to the outside of the steam turbine 1C from the outer discharge port 53 together with the steam flowing through the first main flow path 31. Therefore, it is not necessary to newly provide the steam turbine 1C with a structure for discharging heated steam. As a result, the inner casing heating unit 9C that heats the inner casing 3 by utilizing a part of the steam supplied from the main steam supply unit 8 can be formed with a simple configuration.

<< Fifth Embodiment >>
Next, a fifth embodiment of the steam turbine according to the present invention will be described. The fifth embodiment described below is partially different in that the inner casing has a protrusion. Therefore, in the description of the fifth embodiment, the same parts as those of the first to fourth embodiments are designated by the same reference numerals, and duplicate description will be omitted. That is, the description of the configuration of the steam turbine common to the configurations described in the first to fourth embodiments will be omitted.

The inner casing 3D of the fifth embodiment has a protrusion 35 as shown in FIG. The protruding portion 35 projects from the outer peripheral surface 3b of the inner casing 3D toward the outside in the radial direction Dr. The protrusion 35 is arranged in the second main flow path 51. The protrusion 35 of the present embodiment has an annular shape extending in the circumferential direction Dc with respect to the outer peripheral surface 3b of the inner casing 3D. A plurality of protrusions 35 are provided apart from each other in the axial direction Da.

According to the steam turbine 1D of the fifth embodiment as described above, the protrusion 35 is provided on the outer peripheral surface 3b of the inner casing 3D. Therefore, the surface area of the outer peripheral surface 3b of the inner casing 3D increases. Therefore, the temperature of the heated steam supplied to the second main flow path 51 can be effectively transmitted from the outer peripheral surface 3b side to the inner casing 3D. As a result, the heating steam is effectively used to heat the inner casing 3D. As a result, the inner casing 3D can be expanded faster than the rotor blades 22 and the rotor body 21. As a result, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3D and the clearance between the tip of the stationary blade 4 and the outer peripheral surface 2a of the rotor main body 21 are ensured with high accuracy.

The protrusion 35 of the fifth embodiment is not limited to forming an annular shape extending in the circumferential direction Dc with respect to the outer peripheral surface 3b of the inner casing 3D, and protrudes from the outer peripheral surface 3b of the inner casing 3D. You just have to. Therefore, for example, a plurality of protrusions 35 may be provided so as to form a plate extending in the axial direction Da with respect to the outer peripheral surface 3b of the inner casing 3D and separated from each other in the circumferential direction Dc.

Further, the protrusion 35 may have a smaller protrusion amount from the outer peripheral surface 3b of the inner casing 3D toward the other side in the axial direction Da.

<< Sixth Embodiment >>
Next, a sixth embodiment of the steam turbine according to the present invention will be described. The sixth embodiment described below is partially different in that the inner casing has an inlet communication portion for heating the inner inlet. Therefore, in the description of the sixth embodiment, the same parts as those of the first to fifth embodiments are designated by the same reference numerals, and duplicate description will be omitted. That is, the description of the configuration of the steam turbine common to the configurations described in the first to fifth embodiments will be omitted.

As shown in FIG. 6, the inner casing 3E of the sixth embodiment heats the region forming the inner inlet 32. The inner casing 3E has an inlet communication portion 37 and an adjusting portion 38.

The inlet communication portion 37 makes it possible to circulate a part of the steam flowing through the first main flow path 31 in a region that is partially thickened in the inner casing 3D. Specifically, the inlet communication portion 37 circulates steam in the region forming the inner introduction port 32 in the inner casing 3D. The first main flow path 31 and the outside are communicated with each other on the upstream side in the flow direction of the steam flowing through the first main flow path 31 with respect to the inner introduction port 32. That is, the inlet communication portion 37 penetrates the inner casing 3E in the radial direction Dr on one side of the axial direction Da from the inner introduction port 32.

The adjusting unit 38 adjusts the flow state of steam in the inlet communication unit 37. The adjusting portion 38 of the present embodiment is attached to the inlet communication portion 37 outside the outer casing 5. The adjusting unit 38 is opened or closed by, for example, an operator. The adjusting unit 38 may be a solenoid valve controlled by the control unit 200, like the other valve units.

According to the steam turbine 1E of the sixth embodiment, since the adjusting portion 38 is open, steam can flow in the inlet communication portion 37. In this state, the steam flows into the first main flow path 31, so that the steam flows into the inlet communication portion 37. Therefore, the region forming the inner introduction port 32 in the inner casing 3E can be heated. Therefore, in the inner casing 3E, a region where the temperature does not easily rise can be heated and expanded.

<< Seventh Embodiment >>
Next, a seventh embodiment of the steam turbine according to the present invention will be described. The seventh embodiment described below is partially different in that it has a heater for heating the inner casing. Therefore, in the description of the seventh embodiment, the same parts as those of the first to sixth embodiments are designated by the same reference numerals, and duplicate description will be omitted. That is, the description of the configuration of the steam turbine common to the configurations described in the first to sixth embodiments will be omitted.

The steam turbine 1F of the seventh embodiment includes a heater 90 for heating the inner casing 3 in addition to the inner casing heating portion 9.

The heater 90 is heated by being supplied with electric power from the external power supply unit 90a. The heater 90 of the present embodiment is, for example, an electric heater that utilizes resistance heating, induction heating, or the like. The heater 90 is fixed to the outer peripheral surface 3b of the inner casing 3. The heater 90 is attached to the outer peripheral surface 3b of the inner casing 3 in an annular shape extending in the circumferential direction Dc. A plurality of heaters 90 (two in the present embodiment) are arranged with respect to the outer peripheral surface 3b of the inner casing 3 at intervals in the axial direction Da.

According to the steam turbine 1F of the seventh embodiment, not only the inner casing heating portion 9 but also the heater 90 can heat and expand the inner casing 3. Therefore, by heating the inner casing 3 with the heater 90 together with the heating steam, the inner casing 3 can be expanded much faster than the moving blades 22. As a result, the clearance between the tip of the moving blade 22 and the inner peripheral surface 3a of the inner casing 3 and the clearance between the tip of the stationary blade 4 and the outer peripheral surface of the rotor 2 are ensured with high accuracy.

The heater 90 is not limited to being fixed to the outer peripheral surface 3b of the inner casing 3. The heater 90 may be embedded in the inner casing 3, for example. Further, the heater 90 may be connected to the control unit 200 to heat the inner casing 3 according to the supply state of the heated steam.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the configurations and combinations thereof in the respective embodiments are examples, and the configurations are added or omitted within the scope of the gist of the present invention. , Replacement, and other changes are possible. Further, the present invention is not limited to the embodiments, but only to the scope of claims.

The present invention is not limited to the configuration of each of the above embodiments. Therefore, for example, the protrusion 35 of the fifth embodiment may be provided in any of the second to fourth embodiments and the sixth to seventh embodiments. Similarly, the steam communication unit of the sixth embodiment may be provided in any of the second to fifth embodiments and the seventh embodiment. Similarly, the heater 90 of the seventh embodiment may be provided in any of the second to sixth embodiments.

1, 1A, 1B, 1C, 1D, 1E, 1F ... Steam turbine O ... Axis Da ... Axis direction Dr ... Radial direction Dc ... Circumferential direction 2 ... Rotor 2a ... Rotor outer peripheral surface 21 ... Rotor body 22 ... 3D, 3E ... Inner casing 3a ... Inner peripheral surface of inner casing 3b ... Outer surface of inner casing 31 ... First main flow path 32 ... Inner introduction port 33 ... Inner discharge port 4 ... Static blade 5 ... Outer casing 5a ... Outer casing Inner peripheral surface 51 ... Second main flow path 52 ... Outer introduction port 53 ... Outer discharge port 6 ... Bearing part 7 ... Seal part 71 ... Inner seal part 72 ... Outer seal part 8 ... Main steam supply part 81 ... Main steam pipe 82 ... Main steam valve part 9, 9A, 9B, 9C ... Inner casing heating part 97 ... Heated steam introduction part 98 ... Sub steam supply part 99 ... Storage part 91 ... First supply pipe 92 ... Second supply pipe 93 ... Third supply pipe 94 ... 4th supply pipe 95 ... 5th supply pipe 101 ... 1st valve part 102 ... 2nd valve part 103 ... 3rd valve part 104 ... 4th valve part 105 ... 5th valve part 100 ... Temperature measurement part 200 ... Control Section 201 ... Input section 202 ... Judgment section 203 ... Main steam valve output section 204 ... First valve output section 205 ... Second valve output section 206 ... Third valve output section 207 ... Fourth valve output section 208 ... Fifth valve output Part 301 ... First internal flow path 302 ... Second internal flow path 303 ... Third internal flow path 304, 404 ... Heated steam discharge section 401 ... Steam flow section 402 ... Steam branch pipe 403 ... Steam confluence pipe 501 ... Steam injection part 502 ... Injection part connection pipe 35 ... Projection 37 ... Inlet communication part 38 ... Adjustment part 90 ... Heater 90a ... Power supply part

Claims (10)

A rotor with multiple rotor blades on the outer peripheral surface that rotates around the axis,
An inner casing that covers the rotor from the outside in the radial direction centered on the axis and defines a first main flow path through which steam flows between the rotor and the outer peripheral surface of the rotor.
A plurality of stationary blades provided on the inner peripheral surface of the inner casing and arranged in the first main flow path together with the plurality of moving blades.
An outer casing that covers the inner casing from the outside in the radial direction and defines a second main flow path that communicates with the first main flow path and flows the steam with the outer peripheral surface of the inner casing.
A main steam supply unit that supplies the steam to the first main flow path,
A part of the steam supplied from the main steam supply unit to the first main flow path is diverted and supplied as heated steam to the inner casing to heat the inner casing .
The inner casing heating part is
It has an auxiliary steam supply unit that supplies steam different from the steam supplied from the main steam supply unit as heating steam.
The sub-steam supply unit is a steam turbine that supplies the heated steam to the inner casing when the steam is not supplied to the first main flow path from the main steam supply unit. A rotor with multiple rotor blades on the outer peripheral surface that rotates around the axis,
An inner casing that covers the rotor from the outside in the radial direction centered on the axis and defines a first main flow path through which steam flows between the rotor and the outer peripheral surface of the rotor.
A plurality of stationary blades provided on the inner peripheral surface of the inner casing and arranged in the first main flow path together with the plurality of moving blades.
An outer casing that covers the inner casing from the outside in the radial direction and defines a second main flow path that communicates with the first main flow path and flows the steam with the outer peripheral surface of the inner casing.
A main steam supply unit that supplies the steam to the first main flow path,
A part of the steam supplied from the main steam supply unit to the first main flow path is diverted and supplied as heated steam to the inner casing to heat the inner casing .
The inner casing heating part is
It has a storage unit that stores a part of the steam supplied from the main steam supply unit in advance.
The storage unit is a steam turbine that supplies a part of the stored steam as the heated steam to the inner casing when the steam is not supplied from the main steam supply unit to the first main flow path. The steam turbine according to claim 1 or 2 , wherein the inner casing heating unit joins the heated steam with steam flowing through the second main flow path. The steam turbine according to claim 1 or 2 , wherein the inner casing heating unit has a steam injection unit that injects the heated steam toward the outer peripheral surface of the inner casing. A rotor with multiple rotor blades on the outer peripheral surface that rotates around the axis,
An inner casing that covers the rotor from the outside in the radial direction centered on the axis and defines a first main flow path through which steam flows between the rotor and the outer peripheral surface of the rotor.
A plurality of stationary blades provided on the inner peripheral surface of the inner casing and arranged in the first main flow path together with the plurality of moving blades.
An outer casing that covers the inner casing from the outside in the radial direction and defines a second main flow path that communicates with the first main flow path and flows the steam with the outer peripheral surface of the inner casing.
A main steam supply unit that supplies the steam to the first main flow path,
A part of the steam supplied from the main steam supply unit to the first main flow path is diverted and supplied as heated steam to the inner casing to heat the inner casing .
The inner casing heating unit is a steam turbine that circulates the heated steam inside the inner casing. A rotor with multiple rotor blades on the outer peripheral surface that rotates around the axis,
An inner casing that covers the rotor from the outside in the radial direction centered on the axis and defines a first main flow path through which steam flows between the rotor and the outer peripheral surface of the rotor.
A plurality of stationary blades provided on the inner peripheral surface of the inner casing and arranged in the first main flow path together with the plurality of moving blades.
An outer casing that covers the inner casing from the outside in the radial direction and defines a second main flow path that communicates with the first main flow path and flows the steam between the outer peripheral surface of the inner casing.
A main steam supply unit that supplies the steam to the first main flow path,
A part of the steam supplied from the main steam supply unit to the first main flow path is diverted and supplied as heated steam to the inner casing to heat the inner casing .
A plurality of the inner casing heating portions are arranged apart from the outer peripheral surface of the inner casing in the axial direction in which the axis extends, and are arranged along the outer peripheral surface of the inner casing in the circumferential direction centered on the axis. A steam turbine having a steam circulation unit that circulates the heated steam. Any one of claims 1 to 6 , wherein the inner casing protrudes outward in the radial direction from the outer peripheral surface of the inner casing and has a protrusion arranged in the second main flow path. The steam turbine described in. A rotor with multiple rotor blades on the outer peripheral surface that rotates around the axis,
An inner casing that covers the rotor from the outside in the radial direction centered on the axis and defines a first main flow path through which steam flows between the rotor and the outer peripheral surface of the rotor.
A plurality of stationary blades provided on the inner peripheral surface of the inner casing and arranged in the first main flow path together with the plurality of moving blades.
An outer casing that covers the inner casing from the outside in the radial direction and defines a second main flow path that communicates with the first main flow path and flows the steam with the outer peripheral surface of the inner casing.
A main steam supply unit that supplies the steam to the first main flow path,
A part of the steam supplied from the main steam supply unit to the first main flow path is diverted and supplied as heated steam to the inner casing to heat the inner casing .
The inner casing
An inner inlet for introducing the steam into the first main flow path and
An inlet communication portion that communicates the first main flow path with the outside on the upstream side in the flow direction of steam flowing through the first main flow path with respect to the inner introduction port.
A steam turbine having an adjusting unit for adjusting the flow state of the steam at the inlet communication unit. The steam turbine according to any one of claims 1 to 8 , further comprising a heater for heating the inner casing. The inner casing heating unit has a control unit that controls the supply state of the heated steam.
The control unit, from the start of flowing the vapor in the first main channel, from claim 1 for supplying the heating steam the provisions until the condition in which the inner casing and the rotor blade a predetermined regarded as not in contact The steam turbine according to any one of claims 9 .

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