JP6869777B2 - Drain remover and steam turbine - Google Patents

Description

The present disclosure relates to a drain removing device and a steam turbine equipped with the drain removing device.

In the steam turbine, a device has been devised to discharge the drain, which can be a factor of erosion, to the outside of the steam turbine.

For example, Patent Document 1 discloses a steam turbine in which a drain pocket is provided on the outer peripheral side of a steam passage formed around a rotor shaft. In this steam turbine, a drain pocket is provided in a ring shape between a blade root ring that fixedly supports the final stage stationary blade and an internal passenger compartment provided on the outer peripheral side of the blade root ring, and steam is provided through a slit. It is possible to communicate with the passage. Then, the drain near the inner peripheral surface of the wing root ring is collected in the drain pocket through the slit, and is discharged from the discharge port provided at the lower part of the drain pocket by its own weight or by being sucked. It has become.

Further, Patent Document 2 discloses a steam turbine provided with a drain catcher including a side surface of an outer ring of a nozzle diaphragm and a drain catcher holder attached to the side surface. This drain catcher is composed of a groove formed over the entire circumference between the side surface of the outer ring of the nozzle diaphragm and the drain catcher holder. The drain that jumps into the groove collides with the bottom of the groove formed by the drain catcher holder, then moves to the lower half along the circumferential groove, and is discharged to the outside of the turbine from the discharge port provided in the lower half. It is supposed to be done.

Japanese Patent No. 5653659 Jitsukaisho 60-34502

By the way, when the drain is captured by the above-mentioned drain catcher or the like, a high-speed drain may collide with the drain catcher, so that erosion may occur in the drain catcher.
In this regard, in the drain catcher described in Patent Document 2, the drain is received at the groove bottom formed by the drain catcher holder attached to the side surface of the outer ring of the nozzle diaphragm. Therefore, when erosion occurs at the bottom of the groove where the drain collides, only the drain catcher holder can be replaced, and it is considered that the maintenance cost can be suppressed. However, in the configuration of Patent Document 2, since the opening (drain inlet hole) of the drain catcher for receiving the drain is formed by a plurality of members including the nozzle diaphragm outer ring and the drain catcher holder, there is a manufacturing tolerance of these members. The size of the opening may be affected by the magnitude of the fastening force for fastening these members and the like.

In view of the above circumstances, at least one embodiment of the present invention provides a drain removing device capable of suppressing maintenance costs and easily controlling the dimensions of the drain inlet hole, and a steam turbine provided with the drain removing device. With the goal.

(1) The steam turbine drain removing device according to at least one embodiment of the present invention is
A first annular portion extending in the axial direction from the outer ring portion holding the stationary blade and extending along the circumferential direction, and a first annular portion extending in the circumferential direction.
At least partially, it extends along the circumferential direction on the inner peripheral side of the first annular portion, is held by the first annular portion, and extends in the circumferential direction together with the inner peripheral surface of the first annular portion. A second annular portion having an outer peripheral surface forming an existing drain channel, and the like.
The second annular portion is formed with at least one drain inlet hole that communicates with the drain channel and opens on the inner peripheral surface of the second annular portion.

In the configuration of the above (1), the drain removing device includes a first annular portion and a second annular portion which is located at least partially on the inner peripheral side of the first annular portion and has a drain inlet hole formed therein. .. Therefore, only the second annular portion where the drain easily collides can be formed of the erosion resistant material, or when erosion occurs in the drain removing device, only the second annular portion can be replaced, so that the steam turbine can be replaced. Maintenance cost can be suppressed. Further, in the configuration of the above (1), since the drain inlet hole is formed in the second annular portion, the drain inlet hole is formed as compared with the case where the drain inlet hole is formed by the second annular portion and other members. It is easy to manage the dimensions of.

(2) In some embodiments, in the configuration of (1) above, the first annular portion is configured to be axially fastened to the outer ring portion.

According to the configuration (2) above, the drain removing device can be fixed to the outer ring by fastening the first annular portion to the outer ring portion in the axial direction.

(3) In some embodiments, in the configuration of (1) or (2), the second annular portion is sandwiched between the outer ring portion and the first annular portion in the axial direction.

According to the configuration of (3) above, since the second annular portion is sandwiched between the outer ring portion and the first annular portion in the axial direction, the second annular portion can be held more reliably.

(4) In some embodiments, in any of the configurations (1) to (3) above, the drain inlet hole is a slit extending along the axial direction.

According to the configuration of (4) above, since the drain inlet hole is formed by the slit extending along the axial direction, the drain can be efficiently collected through the drain inlet hole over a wide axial range.

(5) In some embodiments, in any of the configurations (1) to (4) above, the second annular portion includes a plurality of sections extending in the circumferential direction.

According to the configuration of (5) above, since the second annular portion includes a plurality of sections connected in the circumferential direction, the replacement of the second annular portion is performed as compared with the case where the second annular portion is composed of one annular member. Is easy. Further, according to the configuration of (5) above, since the second annular portion includes a plurality of sections connected in the circumferential direction, when erosion occurs, only the section in which the erosion occurs needs to be replaced. Therefore, the maintenance cost of the steam turbine can be suppressed.

(6) In some embodiments, in the configuration of (5) above,
The multiple sections
A first section in which a groove is formed on the first end face in the circumferential direction, and
A second section provided adjacent to the first section in the circumferential direction so that the second end face in the circumferential direction faces the first end face of the first section.
Including
The second end surface of the second section forms the drain inlet hole together with the side wall surface and the bottom surface of the groove of the first section.

According to the configuration of (6) above, the drain inlet hole can be easily formed by the groove machined on the first end surface of the first section and the second end surface of the second section adjacent to the first section. ..

(7) In some embodiments, in the configuration of (6) above,
The second annular portion is continuously provided around the central axis of the second annular portion in the circumferential direction over the entire circumference.
The multiple sections
A plurality of upper half sections forming the upper half region of the second annular portion,
A plurality of lower half sections forming the lower half region of the second annular portion,
Including
The number of the lower half sections is larger than the number of the upper half sections.

According to the configuration of (7) above, the number of lower half sections forming the second annular portion in the lower half region where a large amount of drainage tends to collect is larger than the number of upper half sections, so that the number is larger in the lower half region. Drain inlet hole is formed. Therefore, the drain can be effectively collected through the drain inlet hole formed in the second annular portion.

(8) In some embodiments, in any of the configurations (1) to (7), the second annular portion is configured to be fitable in the axial direction with respect to the first annular portion. To.

According to the configuration of (8) above, the second annular portion is formed so as to be fitted in the axial direction with respect to the first annular portion. Therefore, for example, from the first annular portion of the second annular portion at the time of assembly. The dropout can be suppressed, and the assembleability of the drain removing device is improved.

(9) In some embodiments, in the configuration of (8) above, the second annular portion is configured such that both ends in the axial direction are fitted to the first annular portion, respectively.

According to the configuration of (9) above, both ends of the second annular portion in the axial direction are fitted to the first annular portion, so that, for example, the second annular portion falls off from the first annular portion during assembly. Can be suppressed more reliably, and the assembleability of the drain removing device becomes good.

(10) In some embodiments, in any of the configurations (1) to (9) above, the drain removing device is radial so as to fasten the first annular portion and the second annular portion. Further provided with a fastening member extending along the line.

According to the configuration of (10) above, the first annular portion and the second annular portion are securely fastened to each other by a fastening member extending along the radial direction. Can be done.

(11) In some embodiments, in any of the configurations (1) to (10), the inner peripheral surface of the second annular portion is at least one side of the drain inlet hole in the axial direction. Includes an inclined portion that is inclined so that the distance from the central axis of the outer ring portion increases as the drain inlet hole is approached in the axial direction.

According to the configuration of (11) above, the inner peripheral surface of the second annular portion includes an inclined portion inclined so that the distance from the central axis of the outer ring portion increases as it approaches the drain inlet hole in the axial direction. Therefore, it becomes easy to guide the drain to the drain inlet hole by utilizing the centrifugal force acting on the drain. As a result, the drain can be effectively recovered.

(12) In some embodiments, in any of the configurations (1) to (11) above,
The drain inlet hole is an axial range that overlaps with a seal fin provided between the inner peripheral surface of the second annular portion and the tip surface of the moving blade located on the inner peripheral side of the second annular portion. It is formed on the inner peripheral surface of the second annular portion inwardly or on the upstream side of the axial range.

In the configuration (12) above, the drain inlet is within the axial range that overlaps with the seal fin provided between the inner peripheral surface of the second annular portion and the tip surface of the rotor blade, or on the upstream side of the axial range. A hole is formed. Therefore, since the drain channel communicates with the region where the pressure is higher than the low pressure region immediately after the moving blade in the steam passage through the drain inlet hole, the backflow of drain from the drain channel to the steam passage is unlikely to occur. Further, in the configuration of the above (12), when the drain inlet hole is provided in the vicinity of the seal fin in the axial direction, the drain accumulated on the surface of the moving blade can be easily taken into the drain channel through the drain inlet hole. Therefore, according to the configuration of (12) above, the drain can be effectively recovered.

(13) In some embodiments, in any of the configurations (1) to (12), the drain inlet hole is a cylindrical hole provided so as to penetrate the second annular portion.

According to the configuration of (13) above, since the drain inlet hole is a cylindrical hole penetrating the second annular portion, the drain inlet hole can be easily formed by processing the second annular portion with a drill or the like. it can.

(14) In some embodiments, in any of the configurations (1) to (13) above,
When viewed from the axial direction, the drain inlet hole has an inclination angle φ of 0 ° <φ ≦ 45 ° with respect to the normal direction of the inner peripheral surface of the second annular portion. It is inclined with respect to the normal direction.

According to the configuration of (14) above, the drain inlet hole is inclined so that the inclination angle of the inner peripheral surface of the second annular portion with respect to the normal direction is 0 ° <φ ≦ 45 ° when viewed from the axial direction. Therefore, it becomes easy to guide the drain having a swirling component to the drain channel through the drain inlet hole. As a result, the drain can be effectively recovered.

(15) In some embodiments, in any of the configurations (1) to (14) above,
The total opening area A _inlet of the drain inlet hole and the total flow path cross-sectional area A _exit of the outlet opening of the drain channel satisfy the relationship of A _inlet <A _exit.

According to the configuration of (15) above, the total opening area A _inlet of the drain inlet hole and the total flow path cross-sectional area A _exit of the outlet opening of the drain channel satisfy the relationship of A _inlet <A _{exit, so that the drain channel} When the outlet opening of the is communicated with the low pressure part, it becomes easy to keep the pressure in the drain channel lower than the steam passage of the steam turbine. As a result, the drain can be easily sucked into the drain channel through the drain inlet hole, and the drain can be effectively collected.

(16) The steam turbine according to at least one embodiment of the present invention is
With static wings
The drain removing device according to any one of (1) to (15) above, which is provided on the downstream side of the outer ring portion that holds the stationary blade.
A moving blade provided on the inner peripheral side of the second annular portion of the drain removing device, and
To be equipped.

In the configuration of (16) above, the drain removing device includes a first annular portion and a second annular portion which is located at least partially on the inner peripheral side of the first annular portion and has a drain inlet hole formed therein. .. Therefore, only the second annular portion where the drain easily collides can be formed of the erosion resistant material, or when erosion occurs in the drain removing device, only the second annular portion can be replaced, so that the steam turbine can be replaced. Maintenance cost can be suppressed. Further, in the configuration of the above (16), since the drain inlet hole of the drain removing device is formed in the second annular portion, as compared with the case where the drain inlet hole is formed by the second annular portion and other members. , It is easy to control the dimensions of the drain inlet hole.

(17) In some embodiments, in the configuration of (16) above, the drain channel communicates with a condenser connected to the exhaust chamber of the steam turbine.

According to the configuration of (17) above, since the drain channel communicates with the low-pressure condenser, the inside of the drain channel has a low pressure similar to that of the condenser. Therefore, the drain can be easily sucked into the drain channel through the drain inlet hole, and the drain can be effectively collected.

(18) In some embodiments, in the configuration of (16) or (17) above, the rotor blade is the final stage rotor blade of the steam turbine.

According to the configuration (18) above, since the second annular portion having a drain inlet hole is provided on the outer peripheral side of the final stage rotor blade of the steam turbine having a relatively large amount of drain, the drain of the steam turbine can be effectively recovered. can do.

According to at least one embodiment of the present invention, there is provided a drain removing device capable of suppressing maintenance costs and easily controlling the dimensions of the drain inlet hole, and a steam turbine including the drain removing device.

It is sectional drawing along the axial direction in the vicinity of the final stage rotor blade of the steam turbine which concerns on one Embodiment. It is schematic cross-sectional view along the direction orthogonal to the axial direction of the drain removal device which concerns on one Embodiment. It is an enlarged cross-sectional view which shows the periphery of the drain removal device of the steam turbine shown in FIG. It is an enlarged sectional view which shows the periphery of the drain removal apparatus of the steam turbine which concerns on one Embodiment. It is a perspective view of the section constituting the drain removal device shown in FIGS. 1 and 3. It is a partially enlarged view of the cross-sectional view of the drain removal apparatus shown in FIG. It is a figure which looked at the 2nd annular part of the drain removal apparatus shown in FIG. 1 and FIG. 3 from the inside to the outside in the radial direction. It is a figure which looked at the 2nd annular part of the drain removal apparatus which concerns on one Embodiment from the inside in the radial direction, and looks at the outside.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. Absent.

First, a steam turbine to which the drain removing device according to some embodiments is applied will be described.
FIG. 1 is a cross-sectional view taken along the axial direction in the vicinity of the final stage blade of the steam turbine according to the embodiment. As shown in FIG. 1, the steam turbine 1 includes a rotor 2, a plurality of stages of stationary blades 4 and a plurality of stages of rotor blades 6 provided around the rotor 2, and an inner casing that accommodates the rotor 2 and the rotor blades 6. 3 and. The stationary blades 4 of each stage include a plurality of stationary blades 4 arranged along the circumferential direction of the rotor 2 (hereinafter, may be simply referred to as a circumferential direction). Further, the moving blades 6 of each stage include a plurality of moving blades 6 arranged along the circumferential direction. An outer casing (not shown) is provided on the outside of the inner casing 3.

A steam passage 10 is formed between the inner casing 3 and the rotor 2 along the axial direction of the rotor 2 (hereinafter, may be simply referred to as the axial direction). The plurality of stages of the stationary blades 4 and the plurality of stages of the moving blades 6 are alternately provided along the axial direction in the steam passage 10.
The multi-stage stationary blade 4 includes the final stage stationary blade 5 located on the most downstream side of the flow in the steam passage 10 among the plurality of stage stationary blades 4. Further, the multi-stage rotor blades 6 include the final stage rotor blades 7 located on the most downstream side of the flow in the steam passage 10 among the plurality of stage rotor blades 6.

Each rotor blade 6 is attached to the outer peripheral side of the rotor 2 so as to extend along the radial direction of the rotor 2 (hereinafter, may be simply referred to as the radial direction).
Each of the stationary blades 4 is held by an outer ring portion 8 attached to the inner casing 3 so as to extend along the radial direction, and is supported by the inner casing 3 via the outer ring portion 8. Further, an inner ring portion 9 is provided on the inner peripheral side of the stationary blade 4.

In such a steam turbine 1, when steam is introduced into the inner casing 3 from the steam inlet (not shown), the steam flows through the steam passage 10. Then, the steam flow that expands and accelerates when passing through the stationary blade 4 in the steam passage 10 works on the moving blade 6 to rotate the rotor 2.

The steam flow that has passed through the stationary blades 4 and the moving blades 6 in the inner casing 3 is guided by the flow guide 12 provided on the downstream side of the final stage moving blades 7 and flows into the exhaust chamber (not shown). It may be like this.
Further, a condenser (not shown) may be connected to the exhaust chamber so that the steam flow that has passed through the exhaust chamber flows into the condenser.

The steam turbine 1 further includes a drain removing device 20 for capturing and recovering the drain in the steam passage 10. As shown in FIG. 1, the drain removing device 20 is provided on the downstream side of the outer ring portion 8 holding the stationary blade 4 and on the outer peripheral side of the moving blade 6.
Typically, as shown in FIG. 1, the drain removing device 20 is provided on the downstream side of the outer ring portion 8 holding the final stage stationary blade 5 and on the outer peripheral side of the final stage moving blade 7. In the embodiment of the above, the drain removing device 20 is provided on the downstream side of the outer ring portion 8 that holds the stationary blade 4 on the upstream side of the final stage stationary blade 5, and on the outer peripheral side of the moving blade 6 immediately after the stationary blade 4. You may be.

Hereinafter, the drain removing device 20 according to some embodiments will be described in more detail with reference to FIGS. 1 to 8. In these figures, the same elements are indicated by the same reference numerals.
FIG. 2 is a schematic cross-sectional view taken along a direction orthogonal to the axial direction of the drain removing device 20 according to the embodiment, and is a II-II cross section of the drain removing device 20 shown in FIG. FIG. 3 is an enlarged cross-sectional view showing the periphery of the drain removing device 20 of the steam turbine 1 shown in FIG. 1, and FIG. 4 is an enlarged cross-sectional view showing the periphery of the drain removing device 20 of the steam turbine 1 according to another embodiment. Is.
In FIG. 2, for the sake of simplification of the drawing, the drawing of a part of the first annular portion 30 (the portion between the concave portion 36a (described later; see FIG. 3) in the radial direction and the drain channel 22) is omitted. There is.

As shown in FIGS. 1 and 2, the drain removing device 20 according to the embodiment includes a first annular portion 30 and a second annular portion 40 extending along the circumferential direction.

The first annular portion 30 is provided so as to extend axially from the outer ring portion 8 on the downstream side of the outer ring portion 8 holding the stationary blade 4 (that is, the downstream side in the steam flow direction in the steam passage 10).
In some embodiments, the first annular portion 30 is configured to be axially fastening to the outer ring portion 8. For example, in the exemplary embodiment shown in FIGS. 3 and 4, the first annular portion 30 is fastened to the outer ring portion 8 by a bolt 62 extending in the axial direction.
Alternatively, in some embodiments, the first annular portion 30 may be integrally formed with the outer ring portion 8 so as to extend axially from the outer ring portion 8.

As shown in FIGS. 3 and 4, a flow guide 12 may be connected to the first annular portion 30. Further, the first annular portion 30 and the flow guide 12 may be integrally formed.

The second annular portion 40 is provided so as to extend along the circumferential direction on the inner peripheral side of the first annular portion 30. Further, the second annular portion 40 is held by the first annular portion 30 so that the axial and radial positions are maintained. For example, in the exemplary embodiment shown in FIGS. 3 and 4, the second annular portion 40 is sandwiched between the outer ring portion 8 and the first annular portion 30 in the axial direction. Further, in the exemplary embodiment shown in FIGS. 3 and 4, the first annular portion 30 and the second annular portion 40 are fastened by a bolt 64 (fastening member) extending along the radial direction.

In some embodiments, as shown in FIG. 2, the first annular portion 30 forms an upper half region 32A forming the upper half region of the first annular portion 30 and a lower half region of the first annular portion 30. It has a divided structure including a lower half portion 32B. The upper half portion 32A and the lower half portion 32B are joined by, for example, bolts or welding at the flange portions 34A and 34B provided at the lower end portion and the upper end portion, respectively.

Further, in some embodiments, as shown in FIG. 2, the second annular portion 40 has a divided structure including a plurality of sections 42 connected in a circumferential shape on the inner peripheral side of the first annular portion 30.
In the example shown in FIG. 2, the second annular portion 40 is continuously provided around the central axis of the second annular portion 40 in the circumferential direction over the entire circumference. The plurality of sections 42 constituting the second annular portion 40 include the plurality of upper half sections 42A forming the upper half region of the second annular portion 40 and the plurality of sections 42 forming the lower half region of the second annular portion 40. Includes lower half section 42B and.

As shown in FIGS. 2 to 4, a drain channel 22 extending in the circumferential direction is formed between the first annular portion 30 and the second annular portion 40. The drain channel 22 is formed by an inner peripheral surface 34 of the first annular portion 30 and an outer peripheral surface 44 of the second annular portion 40.
Further, the second annular portion 40 is formed with a drain inlet hole 24 that communicates with the above-mentioned drain channel 22 and opens on the inner peripheral surface 47 of the second annular portion 40.

The drain existing in the steam passage 10 jumps into the drain channel 22 through the drain inlet hole 24, or is sucked into the drain channel 22 through the drain inlet hole 24 due to the pressure difference before and after the drain inlet hole 24, for example. By doing so, it is taken into the drain channel 22. The drain taken into the drain channel 22 is discharged to the outside of the steam turbine 1 through the outlet openings 26A and 26B of the drain channel 22 provided on the side and below.

When the drain jumps into or is sucked into the drain channel 22 through the drain inlet hole 24, the drain easily collides with the second annular portion 40 (for example, the inner peripheral surface 47, etc.) located on the inner peripheral side. ..
In this regard, since the drain removing device 20 described above includes the first annular portion 30 and the second annular portion 40 located at least partially on the inner peripheral side of the first annular portion 30, drains are likely to collide with each other. Only the second annular portion 40 can be formed of an erosion resistant material. Alternatively, when erosion occurs in the drain removing device 20, only the second annular portion 40 can be replaced without replacing the first annular portion 30. Therefore, the maintenance cost of the steam turbine 1 can be suppressed.

If a drain inlet hole is formed between the second annular portion 40 and another member, the size of the drain inlet hole is such that the member forming the drain inlet hole (second annular portion 40 and other members). The dimensions of the drain inlet hole may not be constant, or the dimensions may change during the operation of the steam turbine 1, depending on the manufacturing tolerance of the members) and the magnitude of the fastening force for fastening these members. In some cases.
In this respect, in the drain removing device 20 described above, since the drain inlet hole 24 is formed in the second annular portion 40, it is easy to control the size of the drain inlet hole 24.

In some embodiments, for example, as shown in FIGS. 3 and 4, the inner peripheral surface 47 of the second annular portion 40 and the tip surface 6a of the moving blade 6 located on the inner peripheral side of the second annular portion 40 Seal fins 14 may be provided between the two. By providing such a seal fin 14, the flow rate of steam passing through the gap between the moving blade 6 and the second annular portion 40 can be reduced, and the efficiency decrease of the steam turbine 1 can be suppressed.

As shown in FIGS. 3 and 4, the seal fin 14 may be attached to the second annular portion 40 side. For example, a holder 16 extending along the circumferential direction may be embedded in the second annular portion 40, and the seal fin 14 extending along the circumferential direction may be held by the holder 16. The holder 16 may be fitted in a groove 60 (see FIG. 5) provided in the second annular portion 40.
Although the holder 16 is omitted in FIG. 4 for simplification of the drawing, the holder 16 is shown along the circumferential direction in the axial range in which the drain inlet hole 24 is formed in the second annular portion 40. Holder 16 is embedded. Then, the seal fin 14 is held by the holder 16 along the circumferential direction.
Alternatively, although not particularly shown, in some embodiments, the seal fin 14 may be provided on the tip surface 6a of the rotor blade 6.

In some embodiments, the second annular portion 40 is configured to be axially matable to the first annular portion 30.
For example, in the exemplary embodiment shown in FIGS. 3 and 4, the second annular portion 40 has a protruding portion 46a and a protruding portion 46b projecting downstream at both ends in the axial direction, and the first annular portion 40. Reference numeral 30 denotes a recess 36a and a recess 36b that can be engaged with the protrusion 46a and the protrusion 46b of the second annular portion 40, respectively. Then, the protruding portion 46a is fitted to the recess 36a, and the protruding portion 46b is fitted to the recess 36b.

As described above, since the second annular portion 40 can be fitted to the first annular portion 30 in the axial direction, for example, it is possible to prevent the second annular portion 40 from falling off from the first annular portion 30 at the time of assembly. This makes it possible to improve the assembleability of the drain removing device 20.

In the exemplary embodiment shown in FIGS. 3 and 4, the inner peripheral surface 47 of the second annular portion 40 has an outer ring portion on both sides of the drain inlet hole 24 in the axial direction as it approaches the drain inlet hole 24 in the axial direction. 8 includes inclined portions 48a and 48b tilted so as to increase the distance from the central axis. That is, the inclined portions 48a and 48b have an inclination that approaches the outside in the radial direction as they approach the drain inlet hole 24 in the axial direction.

By providing such inclined portions 48a and 48b on the inner peripheral surface 47 of the second annular portion 40, the drain is drained by utilizing the centrifugal force acting on the drain in the vicinity of the inclined portions 48a and 48b. It becomes easy to lead to the hole 24. As a result, the drain can be effectively recovered.

As shown in FIGS. 3 and 4, the above-mentioned inclined portions 48a may be provided on both sides of the drain inlet hole 24 in the axial direction, or only one side of the drain inlet hole 24 in the axial direction. It may be provided in.

In the exemplary embodiment shown in FIG. 3, the drain inlet hole 24 has an inner peripheral surface 47 of the second annular portion 40 and a tip surface 6a of the moving blade 6 located on the inner peripheral side of the second annular portion 40. It is formed on the upstream side of the axial range that overlaps with the above-mentioned seal fin 14 provided between them.
Further, in the exemplary embodiment shown in FIG. 4, the drain inlet hole 24 has an inner peripheral surface 47 of the second annular portion 40 and a tip surface 6a of the moving blade 6 located on the inner peripheral side of the second annular portion 40. It is formed within an axial range that overlaps with the above-mentioned seal fin 14 provided between the and.

In these embodiments, within an axial range that overlaps with the seal fin 14 provided between the inner peripheral surface 47 of the second annular portion 40 and the tip surface 6a of the rotor blade 6, or upstream of the axial range. A drain inlet hole 24 is formed in the drain inlet hole 24. Therefore, the drain channel 22 communicates with the region where the pressure is higher than the low pressure region immediately after the rotor blade 6 in the steam passage 10 through the drain inlet hole 24. Therefore, backflow of drain from the drain channel 22 to the steam passage 10 is unlikely to occur.
Further, as in the embodiment shown in FIG. 4, when the drain inlet hole 24 is provided within the axial range that overlaps with the seal fin 14 in the axial direction (that is, in the vicinity of the seal fin 14 in the axial direction), the drain inlet hole is provided. The drain accumulated on the surface of the moving blade 6 can be easily taken into the drain channel via the 24. As a result, the drain can be effectively recovered.

As mentioned above, in some embodiments, the second annular portion 40 includes a plurality of circumferential sections 42 (42A, 42B) (see FIG. 2).

In this case, the replacement of the second annular portion 40 is easier than in the case where the second annular portion 40 is composed of an annular single member. Further, in this case, since the second annular portion 40 includes a plurality of sections 42 connected in the circumferential direction, when erosion occurs in the second annular portion 40, only the section 42 in which the erosion occurs needs to be replaced. .. Therefore, the maintenance cost of the steam turbine 1 can be suppressed.

FIG. 5 is a perspective view of a section 42 constituting the drain removing device 20 shown in FIG. 1 (and FIG. 3), and FIG. 6 is a partially enlarged view of a cross-sectional view of the drain removing device 20 shown in FIG. is there. Further, FIG. 7 is a view of the second annular portion 40 of the drain removing device 20 shown in FIG. 1 (and FIG. 3) as viewed from the inside to the outside in the radial direction, and FIG. 8 is a view of the drain according to another embodiment. It is a figure which looked at the 2nd annular part 40 of the removal apparatus 20 from the inside in the radial direction from the outside.

In some embodiments, the sections 42 constituting the drain removing device 20 are, for example, as shown in FIGS. 5 to 7, a first end surface 52 and a second end surface 54 (FIG. 6) which are both end faces in the circumferential direction. And FIG. 7). A groove 55 having a bottom surface 56 and a side wall surface 58 is formed on the first end surface 52 of the section 42.

As shown in FIG. 6, when focusing on the first section 101 and the second section 102 that are adjacent to each other among the plurality of sections 42 arranged in the circumferential direction, the first section 101 and the second section 102 are the first section 101. The first end surface 52 of the above and the second end surface 54 of the second section 102 are provided so as to face each other. A drain inlet hole 24 is formed by the side wall surface 58 and the bottom surface 56 of the groove 55 provided on the first end surface 52 of the first section and the second end surface 54 of the second section.

In this way, the drain inlet hole 24 can be easily formed by the groove 55 machined on the first end surface 52 of the first section 101 and the second end surface 54 of the second section 102 adjacent to the first section 101. Can be done.

In some embodiments, the drain inlet hole 24 is a slit extending along the axial direction. For example, in the example shown in FIGS. 5 to 7, the groove 55 formed in the first end surface 52 of the first section 101 has a bottom surface 56 extending along the axial direction and a side extending along the circumferential direction. It has a wall surface 58, and the axial length of the bottom surface 56 is longer than the circumferential length of the side wall surface 58. The drain inlet hole 24 formed by the above-mentioned groove 55 provided on the first end surface 52 of the first section 101 and the second end surface 54 of the adjacent second section 102 is a slit extending along the axial direction. Is.

If the drain inlet hole 24 is a slit extending along the axial direction as described above, drain can be efficiently collected through the drain inlet hole 24 over a wide axial range.

In some embodiments, as shown in FIG. 2, the second annular portion 40 is provided continuously around the central axis of the second annular portion 40 in the circumferential direction over the entire circumference. The plurality of sections 42 constituting the second annular portion 40 include a plurality of upper half sections 42A forming the upper half region of the second annular portion 40 and a plurality of lower halves forming the lower half region of the second annular portion 40. Includes section 42B and. Of these sections 42 (upper half section 42A and lower half section 42B), sections 42 adjacent to each other are the first section 101 and the second section 102 described above. That is, the drain inlet hole 24 is formed by the bottom surface 56 and the side wall surface 58 of the groove 55 formed on the first end surface 52 of each section 42 and the second end surface 54 of the section adjacent to the section 42. The number of lower half sections 42B is larger than the number of upper half sections 42A. In the exemplary embodiment shown in FIG. 2, the second annular portion 40 includes six upper half sections 42A and nine lower half sections 42B.

In this way, by increasing the number of lower half sections 42B forming the second annular portion 40 in the lower half region where a large amount of drainage is likely to collect, the number of upper half sections 42A in the upper half region is increased in the lower half region. More drain inlet holes 24 are formed. Therefore, the drain can be effectively collected through the drain inlet hole 24 formed in the second annular portion 40.

The drain inlet hole 24 may be provided along the normal direction (that is, along the radial direction) of the inner peripheral surface 47 of the second annular portion 40 when viewed from the axial direction.

Alternatively, as shown in FIG. 6, for example, the drain inlet hole 24 is relative to the normal direction of the inner peripheral surface 47 of the second annular portion 40 (indicated by the straight line Ln in FIG. 6) when viewed from the axial direction. It may be provided at an angle. The direction of inclination of the drain inlet hole 24 with respect to the above-mentioned normal direction when viewed in the axial direction may be a direction corresponding to the rotation direction of the rotor 2 (see FIG. 1).

In some embodiments, the inclination angle φ (see FIG. 6) of the drain inlet hole 24 with respect to the normal direction of the inner peripheral surface 47 of the second annular portion when viewed from the axial direction is 0 ° <φ ≦ 45 °. Meet.

In this way, the drain inlet hole 24 is provided so as to be inclined so that the above-mentioned inclination angle φ is 0 ° <φ ≦ 45 °, so that the drain having a swirling component can be provided through the drain inlet hole to the drain channel 22. It becomes easier to lead to. As a result, the drain can be effectively recovered.

In some embodiments, the total opening area _{A Inlet,} drain inlet hole 24, outlet opening 26A of the drain channel 22, 26B and _the total flow path cross-sectional area _{A exit} (see FIG. _{2), A inlet <A exit} of Meet the relationship.

As described above, if the total opening area A _inlet of the drain inlet hole 24 and the total flow path cross-sectional area A _exit of the outlet openings 26A and 26B of the drain channel 22 satisfy the relationship of A _inlet <A _{exit, the drain channel 22} When the outlet openings 26A and 26B of the above are communicated with the low pressure portion, the pressure in the drain channel 22 can be easily maintained lower than that of the steam passage 10 of the steam turbine 1. As a result, the drain can be easily sucked into the drain channel 22 through the drain inlet hole 24, and the drain can be effectively collected.

The above-mentioned low-pressure portion may be a condenser connected to the exhaust chamber of the steam turbine 1. That is, in some embodiments, the drain channel 22 may communicate with the condenser described above.

In this case, since the drain channel 22 communicates with the low-pressure condenser, the inside of the drain channel 22 has a low pressure similar to that of the condenser. Therefore, the drain can be easily sucked into the drain channel through the drain inlet hole 24, and the drain can be effectively collected.

In some embodiments, for example, as shown in FIG. 8, the drain inlet hole 24 may be a cylindrical hole provided so as to penetrate the second annular portion 40.
As described above, when the drain inlet hole 24 is a cylindrical hole penetrating the second annular portion 40, the drain inlet hole 24 can be easily formed by processing the second annular portion 40 with a drill or the like.

In the exemplary embodiment shown in FIG. 8, one or more cylindrical holes (drain inlet holes 24) are provided in the sections 42 constituting the second annular portion 40 so as to be arranged along the circumferential direction. .. As a result, a plurality of cylindrical holes (drain inlet holes 24) arranged along the circumferential direction are formed in the second annular portion 40.

Further, although not particularly shown, in some embodiments, the drain inlet hole 24 may be a groove formed continuously along the circumferential direction.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes a modified form of the above-described embodiments and a combination of these embodiments as appropriate.

In the present specification, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial". Strictly represents not only such an arrangement, but also a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
Further, in the present specification, the expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also within a range in which the same effect can be obtained. , The shape including the uneven portion, the chamfered portion, etc. shall also be represented.
Further, in the present specification, the expression "comprising", "including", or "having" one component is not an exclusive expression excluding the existence of another component.

1 Steam turbine 2 Rotor 3 Inner casing 4 Static blade 5 Final stage stationary blade 6 Moving blade 6a Chip surface 7 Final stage moving blade 8 Outer ring part 9 Inner ring part 10 Steam passage 12 Flow guide 14 Seal fin 16 Holder 20 Drain removal device 22 Drain channel 24 Drain inlet hole 26A Outlet opening 26B Outlet opening 30 First annular portion 32A Upper half 32B Lower half 34 Inner peripheral surface 34A Flange 34B Flange 36a Recess 36b Recess 40 Second annular portion 42 Section 42A Upper half section 42B Lower half Section 44 Outer surface 46a Protruding part 46b Protruding part 47 Inner peripheral surface 48a Inclined part 48b Inclined part 52 First end surface 54 Second end surface 55 Groove 56 Bottom surface 58 Side wall surface 60 Groove 62 Bolt 64 Bolt 101 First section 102 Second section

Claims (16)

A first annular portion extending axially from the outer ring portion holding the stationary blade and extending along the circumferential direction,
At least partially, it extends along the circumferential direction on the inner peripheral side of the first annular portion, is held by the first annular portion, and extends in the circumferential direction together with the inner peripheral surface of the first annular portion. A second annular portion having an outer peripheral surface forming an existing drain channel, and the like.
At least one drain inlet hole that communicates with the drain channel and opens on the inner peripheral surface of the second annular portion is formed in the second annular portion .
The second annular portion is configured to be fitable in the axial direction with respect to the first annular portion.
The second annular portion is a drain removing device for a steam turbine, characterized in that both ends in the axial direction are fitted to the first annular portion, respectively. The drain removing device for a steam turbine according to claim 1, wherein the first annular portion is configured to be able to be fastened to the outer ring portion in the axial direction. The drain removing device for a steam turbine according to claim 1 or 2, wherein the second annular portion is sandwiched between the outer ring portion and the first annular portion in the axial direction. The drain removing device for a steam turbine according to any one of claims 1 to 3, wherein the drain inlet hole is a slit extending along the axial direction. The drain removing device for a steam turbine according to any one of claims 1 to 4, wherein the second annular portion includes a plurality of sections connected in the circumferential direction. The multiple sections
A first section in which a groove is formed on the first end face in the circumferential direction, and
A second section provided adjacent to the first section in the circumferential direction so that the second end face in the circumferential direction faces the first end face of the first section.
Including
The drain removing device for a steam turbine according to claim 5, wherein the second end surface of the second section forms the drain inlet hole together with the side wall surface and the bottom surface of the groove of the first section. A first annular portion extending in the axial direction from the outer ring portion holding the stationary blade and extending along the circumferential direction, and a first annular portion extending in the circumferential direction.
At least partially, it extends along the circumferential direction on the inner peripheral side of the first annular portion, is held by the first annular portion, and extends in the circumferential direction together with the inner peripheral surface of the first annular portion. A second annular portion having an outer peripheral surface forming an existing drain channel, and the like.
At least one drain inlet hole that communicates with the drain channel and opens on the inner peripheral surface of the second annular portion is formed in the second annular portion.
The second annular portion includes a plurality of sections extending in the circumferential direction.
The multiple sections
A first section in which a groove is formed on the first end face in the circumferential direction, and
A second section provided adjacent to the first section in the circumferential direction so that the second end face in the circumferential direction faces the first end face of the first section.
Including
The second end surface of the second section forms the drain inlet hole together with the side wall surface and the bottom surface of the groove of the first section.
The second annular portion is continuously provided around the central axis of the second annular portion in the circumferential direction over the entire circumference.
The multiple sections
A plurality of upper half sections forming the upper half region of the second annular portion,
A plurality of lower half sections forming the lower half region of the second annular portion,
Including
The number of the lower half section, steam turbine drain remover you characterized by greater than the number of the upper half section. The steam turbine according to any one of claims 1 to 7 , further comprising a fastening member extending along the radial direction so as to fasten the first annular portion and the second annular portion. Drain removal device. The inner peripheral surface of the second annular portion increases in distance from the central axis of the outer ring portion as it approaches the drain inlet hole in the axial direction on at least one side of the drain inlet hole in the axial direction. The drain removing device for a steam turbine according to any one of claims 1 to 8 , further comprising an inclined portion inclined so as to be. The drain inlet hole is an axial range that overlaps with a seal fin provided between the inner peripheral surface of the second annular portion and the tip surface of the moving blade located on the inner peripheral side of the second annular portion. The drain removing device for a steam turbine according to any one of claims 1 to 9 , wherein the steam turbine drainage device is formed on the inner peripheral surface of the second annular portion inwardly or on the upstream side of the axial range. .. The drain removing device for a steam turbine according to any one of claims 1 to 10 , wherein the drain inlet hole is a cylindrical hole provided so as to penetrate the second annular portion. When viewed from the axial direction, the drain inlet hole has an inclination angle φ of 0 ° <φ ≦ 45 ° with respect to the normal direction of the inner peripheral surface of the second annular portion. The drain removing device for a steam turbine according to any one of claims 1 to 11 , wherein the device is inclined with respect to the normal direction. Any of claims 1 to 12 , wherein the total opening area A _inlet of the drain inlet hole and the total flow path cross-sectional area A _exit of the outlet opening of the drain channel satisfy the relationship of A _inlet <A _exit. The steam turbine drain removal device according to item 1. With static wings
The drain removing device according to any one of claims 1 to 13 , which is provided on the downstream side of the outer ring portion that holds the stationary blade.
A moving blade provided on the inner peripheral side of the second annular portion of the drain removing device, and
A steam turbine characterized by being equipped with. The steam turbine according to claim 14 , wherein the drain channel communicates with a condenser connected to an exhaust chamber of the steam turbine. The steam turbine according to claim 14 or 15 , wherein the rotor blade is the final stage rotor blade of the steam turbine.

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