JP2018172976A - Steam valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam valve which enables further reduction of pressure loss of supplied steam.SOLUTION: A steam valve of the invention includes: a casing 10 having a steam passage in which steam S flows from the upstream side α to the downstream side β; a valve body 60 which is disposed in a valve chamber 14 forming the steam passage so as to reciprocate between a close position and an open position; and a valve seat 40 on which the valve body 60 is seated in the close position and which is supported by the casing 10. The steam passage includes: an upstream side passage 12A in which the steam S flows toward the valve chamber 14 in a horizontal direction H; and a first downstream side passage 13A into which the steam S flowing from the valve chamber 14 flows. In the first downstream side passage 13A, the steam S flowing from the valve chamber 14 in a vertical direction V flows along a curved guide surface to flow toward the downstream side β in the horizontal direction H.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steam valve for supplying or shutting off steam to, for example, a steam turbine.

  In a steam turbine used in a thermal power plant, a steam valve is provided to supply or shut off steam to the steam turbine. Steam valve can supply or shut off steam by moving the valve stem with an actuator and changing the distance between the valve body provided on the valve stem and the valve seat provided on the casing of the steam valve. It is common that

Improving the performance of steam turbines is an important issue for the effective use of energy resources. In order to further improve the performance of the steam turbine, it is necessary to suppress the pressure loss when supplying steam to the steam turbine as much as possible.
Patent Document 1 proposes a steam valve that can reduce the pressure loss of the inflowing steam by devising the shape of the valve seat and the arrangement of the valve seat and the valve body in the casing.

Japanese Patent No. 5613789

  Although the proposal of Patent Document 1 is effective in reducing the pressure loss in the steam valve, reduction of the pressure loss in the steam valve is always required. Then, an object of this invention is to provide the steam valve which can further reduce the pressure loss of the supplied steam.

The steam valve of the present invention is disposed in a casing having a steam channel through which steam flows from the upstream side toward the downstream side, and in a valve chamber that forms the steam channel so as to be capable of reciprocating between a closed position and an open position. And a valve seat supported by a casing and seated in the closed position.
The steam flow path includes an upstream flow path in which steam flows in a horizontal direction toward the valve chamber, and a downstream flow path in which steam flows from the valve chamber, and the downstream flow path extends vertically from the valve chamber. The inflowing steam flows along the curved guide surface, and thus flows in the horizontal direction toward the downstream side.

  The steam flow path in the steam valve of the present invention includes an upstream flow path connected to the valve chamber, a valve chamber connected to the upstream flow path, a first downstream flow path connected to the valve chamber, and a first downstream flow path. It is preferable that the second downstream flow path is connected, the steam flows along a curved guide surface in the first downstream flow path, and the steam flows in the horizontal direction in the second downstream flow path.

  The steam valve of the present invention preferably includes a valve rod that reciprocally moves the valve body in the vertical direction, and the valve rod penetrates the casing and is drawn out below the casing.

The casing in the steam valve of the present invention preferably holds a bush that supports the valve rod in a slidable manner.
The front end of the bush is exposed to the first downstream channel, and the front end can form an inclined surface following the curved guide surface.
In this case, the bush is preferably configured integrally with the tip, or a combination of an upper structure including an inclined surface of the tip and a lower structure separate from the upper structure. .
Further, the bush can be prevented from being exposed to the first downstream channel by being accommodated so as to be covered by the casing.

  According to the present invention, by curving the inner surface of the casing that defines the steam flow path downstream of the valve chamber, the steam guided downward in the vertical direction from the valve chamber at the position where the valve element is disposed. Can be smoothly guided in the horizontal direction. Thereby, the pressure loss of the steam passing through the steam valve can be suppressed.

1 is a block diagram illustrating a configuration of a gas turbine power generation system according to a first embodiment of the present invention. (A) is sectional drawing which shows the state in which the steam valve of 1st Embodiment has shielded steam, (b) is sectional drawing which shows the state in which the steam valve of 1st Embodiment is flowing the steam. It is. It is a top view of the steam valve of the present invention. (A) is sectional drawing of the steam valve of the similar example of 1st Embodiment of this invention, (b) is the decomposition | disassembly partial enlarged view of (a). (A) is sectional drawing of the steam valve of 2nd Embodiment of this invention, (b) is the decomposition | disassembly partial enlarged view of (a).

  Hereinafter, the steam valve 7 according to the embodiment of the present invention will be described. In the present embodiment, the steam valve 7 of the present invention is applied to a steam turbine power plant 1.

[First Embodiment]
As shown in FIG. 1, the steam turbine power plant 1 includes a steam turbine 2, a generator 3 that is driven by the rotation of the steam turbine 2, and a condenser 4 that returns the steam S that has worked in the steam turbine 2 to water. A feed water pump 5 for boosting the water returned by the condenser 4, a boiler 6 for heating the water boosted by the feed water pump 5 to re-steam S, and a pipe connecting the boiler 6 and the steam turbine 2. And a provided steam valve 7.
When the steam S flowing into the steam valve 7 from the upstream side α passes through the valve chamber 14 and flows through the flow path on the downstream side β, the steam valve 7 ideally generates a laminar flow without generating a swirling flow. Since it is discharged while being maintained, the pressure loss when the steam S passes through the steam valve 7 can be suppressed.

[Steam valve 7]
As shown in FIG. 2A, the steam valve 7 of the present embodiment includes a strainer 30 that captures foreign matter and prevents it from flowing to the downstream side β, a valve body 60 that is disposed inside the strainer 30, A valve rod 70 connected to the valve body 60 and moved in the vertical direction V, a bush 50 that slidably supports the valve rod 70, and a valve seat 40 on which the valve body 60 is seated in the closed position are provided. The steam valve 7 includes a casing 10 that houses these elements, and an upper lid 20 that closes the opening 11 at the upper end of the casing 10.
The steam valve 7 moves the valve rod 70 in the vertical direction V by an actuator (not shown), thereby closing the valve body 60 between the closed position (FIG. 2 (a)) and the open position (FIG. 2 (b)). Are moved up and down in the vertical direction V. The steam valve 7 can shut off or supply the steam S by switching between the closed position and the open position, and the supply amount of the steam S to the steam turbine 2 can be generally adjusted by changing the open position. Is possible.
Hereinafter, each element of the steam valve 7 will be described.
In the present embodiment, the steam S flows in the horizontal direction H, and the upstream side α and the downstream side β are defined based on the direction in which the steam S flows. The upstream side α and the downstream side β indicate a relative positional relationship.

[Case 10]
As shown in FIGS. 2A and 2B, the casing 10 is connected to the casing 10 to introduce the steam S into the steam valve 7, and the valve chamber 14 is connected to the downstream side β of the introduction pipe 12. And a discharge pipe 13 connected to the downstream side β of the valve chamber 14 and an opening 11 closed by the upper lid 20. The casing 10 can be formed by casting an iron-based metal material. Other components such as the valve seat 40 and the valve body 60 of the steam valve 7 are made of an iron-based metal material except for the bush 50.
As shown in FIGS. 2 (a) and 2 (b), the introduction pipe 12 and the discharge pipe 13 are arranged with their positions shifted in the vertical direction V when the steam valve 7 is viewed from the side. As shown in FIG. 3, when the steam valve 7 is viewed from above, it is arranged on the same straight line.

  A crank-shaped steam flow path is formed in the casing 10 by the introduction pipe 12 (upstream flow path 12A), the valve chamber 14, the first downstream flow path 13A, and the discharge pipe 13 (second downstream flow path 13B). The That is, the steam S flowing in from the introduction pipe 12 passes through the valve chamber 14 and is then discharged from the discharge pipe 13 via the first downstream flow path 13A.

  The upstream flow path 12 </ b> A partitioned inside the introduction pipe 12 has a circular opening shape, and the upstream flow path 12 </ b> A extends straight along the horizontal direction H.

  The discharge pipe 13 includes a first downstream channel 13A and a second downstream channel 13B that are partitioned inside. The first downstream channel 13A is connected to the valve chamber 14, and the second downstream channel 13B is connected to the downstream side of the first downstream channel 13A. The first downstream channel 13A and the second downstream channel 13B both have circular openings.

In the first downstream channel 13A, the outer peripheral surface 16 and the inner peripheral surface 17 form an arc from the portion connected to the valve chamber 14, the portion connected to the valve chamber 14 faces the vertical direction V, and the second downstream side The part connected to the side flow path 13B faces the horizontal direction H. The outer peripheral surface 16 has a larger radius of curvature than the inner peripheral surface 17.
On the other hand, the second downstream channel 13B extends straight along the horizontal direction H.
The outer peripheral surface 16 forms a guide surface made of a smooth curved surface having no undulations, including the inclined surface 51 of the bush 50 exposed to the first downstream channel 13A. Similarly, the inner peripheral surface 17 is a smooth curved surface having no undulations.

[Valve 14]
The valve chamber 14 is a space that accommodates the valve body 60, the strainer 30, and the valve body guide 21. As shown in FIG. 3, this space has a circular shape when viewed from above.
As shown in FIG. 2A, the valve chamber 14 has an inlet 14A provided on the upstream side α in the horizontal direction H connected to the upstream flow path 12A. An outlet 14B provided below the vertical direction V is connected to the first downstream channel 13A. A valve seat 40 is supported by the casing 10 at the outlet 14 </ b> B of the valve chamber 14.

When the valve body 60 is seated on the valve seat 40, the steam flow path is closed.
The valve seat 40 is formed in an annular shape. The valve seat 40 has an inner diameter equal to the diameter of the outlet 14B.

[Bush 50]
The bush 50 is a cylindrical member that slidably supports the valve stem 70.
As shown in FIG. 2A, the bush 50 has an inclined surface 51 exposed at the first downstream channel 13A at the tip. The bush 50 is provided with a seal member 52 that ensures airtightness with the valve stem 70.
The bush 50 is formed such that the inclined surface 51 is formed as an inclined surface following the guide surface of the outer peripheral surface 16 of the first downstream channel 13A and is substantially flush with the outer peripheral surface 16.
The seal member 52 is a gland packing formed in an annular shape, and suppresses the outflow of the steam S flowing through the first downstream channel 13 </ b> A from between the bush 50 and the valve rod 70.
The bush 50 is preferably made of a low-friction metal material so that the valve stem 70 can slide smoothly, but an appropriate material that can withstand the steam temperature can be appropriately selected and used.

The casing 10 includes a storage chamber 18 that stores and holds the bush 50. The upper end of the storage chamber 18 has an opening in the first downstream channel 13A.
The bush 50 is accommodated in the storage chamber 18 so that the inclined surface 51 is flush with the outer peripheral surface 16 that defines the first downstream channel 13A. Further, the bush 50 is accommodated in the storage chamber 18 without a gap in the radial direction.

In addition, the casing 10 includes an insertion hole 19 that passes through the bush 50 and draws the valve rod to the outside of the casing 10. The insertion hole 19 communicates the storage chamber 18 and the outside of the casing 10.
The diameter of the insertion hole 19 is formed so that the valve rod 70 can be inserted without a gap.

[Strainer 30]
The strainer 30 captures the foreign matter contained in the steam S flowing through the steam flow path flowing to the downstream side β.
As shown in FIG. 3, the strainer 30 includes a cylindrical main body 31 and a plurality of rectifying plates 32 extending from the inner peripheral surface of the main body 31 inward in the radial direction.
The strainer 30 is accommodated in the valve chamber 14 of the casing 10.

The main body 31 is composed of a mesh having a large number of holes penetrating the front and back.
The rectifying plate 32 suppresses the swirling flow of the steam S in the circumferential direction inside the strainer 30.
As shown in FIG. 2, the rectifying plate 32 protrudes more radially inward on the lower side mainly in contact with the steam S flowing into the steam valve 7.
As shown in FIG. 3, the plurality of rectifying plates 32 are equally arranged in the circumferential direction.

[Valve 60]
When the valve body 60 is seated on the valve seat 40, the steam passage is closed.
The valve body 60 is formed in a columnar shape, and as shown in FIG. 2A, the entire circumference of the edge of the lower surface is seated with the valve seat 40.
When the valve body 60 descends from above in the vertical direction V and the valve body 60 and the valve seat 40 are seated, the steam flow path is blocked and the steam S is prevented from flowing from the valve chamber 14 to the downstream side β.
On the other hand, when the valve body 60 in contact with the valve seat 40 rises and the valve body 60 moves away from the valve seat 40, the steam S flows from the valve chamber 14 to the first downstream channel 13 </ b> A on the downstream side β, It flows to the downstream channel 13B.

[Valve 70]
The valve stem 70 reciprocates along the vertical direction V, that is, moves up and down by transmitting the driving force of the actuator.
As shown in FIGS. 2A and 2B, the valve rod 70 passes through the inside and the outside of the casing 10 through the storage chamber 18 and the insertion hole 19.
One end of the valve stem 70 is fixed to the valve body 60 inside the casing 10. In addition, the other end of the casing 10 is connected to an actuator (not shown). By driving the actuator, the valve body 60 can be raised and lowered via the valve rod 70.

[Upper lid 20]
The upper lid 20 closes the opening 11 at the upper end of the casing 10.
As shown in FIG. 2A, the upper lid 20 includes a valve body guide 21 on a surface that comes into contact with the opening 11.
The upper lid 20 is fixed to the casing 10 by fastening means (not shown). This
The steam S inside the casing 10 is prevented from leaking from the opening 11 to the outside.

The valve body guide 21 guides the movement of the valve body 60 in the vertical direction V.
As shown in FIG. 2A, the valve element guide 21 is formed in a bottomed cylindrical shape, and is arranged so that the opening faces downward in the vertical direction V.
The valve body guide 21 reduces the pressure difference upstream and downstream of the valve body 60 by narrowing the flow path inside the strainer 30 inside the valve chamber 14, and facilitates sliding of the valve body 60. Be placed.

[Flow of steam S]
Next, the flow of the steam S in the steam valve 7 will be described with reference to FIG.
The steam S supplied from the upstream side to the upstream flow path 12A of the introduction pipe 12 flows in the horizontal direction H through the upstream flow path 12A and reaches the valve chamber 14 on the downstream side β.
The steam S that passes through the valve chamber 14 and flows into the first downstream channel 13A from the outlet 14B of the valve chamber 14 has a downward velocity component. Since the outer peripheral surface 16 and the inner peripheral surface 17 of the first downstream channel 13A are curved in an arc shape toward the downstream β, the steam S flowing into the first downstream channel 13A And has a velocity component in the horizontal direction H. The steam S that has passed through the first downstream channel 13A flows in the horizontal direction H through the second downstream channel 13B.

[Effect of steam valve 7]
Next, the effect which the steam valve 7 of this embodiment shows is demonstrated.
In the steam valve 7 of the present embodiment, the steam S flowing into the valve chamber 14 from the introduction pipe 12 changes its direction along the outer peripheral surface 16 facing the first downstream channel 13A and is directed to the second downstream channel 13B. Flowing. The outer peripheral surface 16 forms a smooth curved surface with no undulations, including the inclined surface 51 of the bush 50 exposed in the first downstream channel 13A. Accordingly, when passing through the first downstream side flow path 13A, the steam S does not cause a swirling flow that causes pressure loss or even a slight amount. For this reason, the pressure loss of the steam S passing through the steam valve 7 can be suppressed.

  Further, the bush 50 is formed so that the inclined surface 51 is flush with the outer peripheral surface 16 of the first downstream channel 13 </ b> A, and prevents the swirling flow from being generated when the steam S collides with the bush 50. Therefore, an increase in pressure loss can be suppressed.

Further, the steam valve 7 has a structure in which the valve rod 70 is drawn downward through the casing 10.
Here, in the case of the structure in which the valve stem 70 penetrates the upper lid 20 and is drawn upward, it is necessary to consider the valve stem 70 when removing the upper lid 20 when the steam valve 7 is inspected or maintained. There is. Therefore, the burden of removing the upper lid 20 is heavy.
On the other hand, the steam valve 7 from which the valve stem 70 is drawn downward through the casing 10 does not need to consider the valve stem 70 when removing the upper lid 20. It is possible to reduce the work load of the worker who performs the operation.

[Modification of First Embodiment]
Next, Modification 1 of the first embodiment will be described with reference to FIG. In FIG. 4, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

The steam valve 7 described above includes the bush 50 integrally. However, in the present embodiment, as shown in FIG. 4B, the bush 50 can be divided into an upper structure 53 in which the inclined surface 51 is formed and a lower structure 54.
As shown in FIG. 4A, the upper structure 53 and the lower structure 54 are arranged in this order from above in the storage chamber 18. Also in this modification, the upper structure 53 and the lower structure 54 are accommodated and held in the storage chamber 18 so that the inclined surface 51 of the upper structure 53 is flush with the outer peripheral surface 16.

  In the modified example, since the lower structure 54 has a simple cylindrical shape, a general bushing that can withstand a high temperature operation environment can be applied. On the other hand, if only the part of the upper structure 53 is produced so as to have the inclined surface 51, the production is easy because the size is small compared with the case where the entire bush 50 is integrally formed.

[Second Embodiment]
Next, a second embodiment will be described with reference to FIG. In FIG. 5, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.

In the steam valve 8 of the second embodiment, the storage chamber 18 is closed with the outer peripheral surface 16 serving as the upper lid 55 with respect to the first downstream channel 13A. The surface of the upper lid 55 forms a part of the outer peripheral surface 16.
Therefore, the bush 50 accommodated in the accommodating chamber 18 is accommodated so as to be covered by the casing 10 without being exposed to the first downstream channel 13A. The upper lid 55 is formed with a through hole 56 through which the valve rod 70 penetrates the front and back surfaces. The through hole 56 has a smaller diameter than the bush 50, and the bush 50 is connected to the first downstream channel 13A. It is not an exposed element.

  In the second embodiment, the bush 50 is accommodated in the storage chamber 18 from the opening in the vertical direction V, and a lower lid 57 is provided in the storage chamber 18 to hold the bush 50. The lower lid 57 is formed with an insertion hole 19 through which the valve rod 70 is inserted.

According to this embodiment, the bush 50 can be accommodated in the storage chamber 18 without being exposed to the first downstream channel 13A. Therefore, since the outer peripheral surface 16 that divides the first downstream channel 13A is integrally formed as the casing 10, it can have a smoother curved surface.
Moreover, since the bush 50 can apply a simple cylindrical commercial item, the effort which forms the inclined surface 51 can be saved. Therefore, the second embodiment can reduce the cost of the bush 50.

  The preferred embodiment of the present invention has been described above, but the configuration described in the above embodiment is selected or changed to another configuration as long as it does not depart from the gist of the present invention. be able to.

  For example, the radius of curvature of the outer peripheral surface 16 can be set to an appropriate value based on conditions such as the flow rate and flow velocity of the steam S passing through the steam flow path.

DESCRIPTION OF SYMBOLS 1 Steam turbine power plant 2 Steam turbine 3 Generator 4 Condenser 5 Water supply pump 6 Boiler 7 Steam valve 8 Steam valve 10 Casing 11 Opening 12 Introduction pipe 12A Upstream flow path 13 Discharge pipe 13A First downstream flow path 13B 1st Two downstream flow paths 14 Valve chamber 14A Inlet 14B Outlet 16 Outer peripheral surface 17 Inner peripheral surface 18 Storage chamber 19 Insertion hole 20 Upper lid 21 Valve element guide 30 Strainer 31 Main body 32 Rectifier plate 40 Valve seat 50 Bush 51 Inclined surface 52 Seal member 53 Upper structure 54 Lower structure 55 Upper lid 56 Through hole 57 Lower lid 60 Valve body 70 Valve rod S Steam H Horizontal direction V Vertical direction α Upstream side β Downstream side

Claims (7)

A casing having a steam channel through which steam flows from the upstream side toward the downstream side;
A valve element disposed in a valve chamber forming the steam flow path so as to be capable of reciprocating between a closed position and an open position;
A valve seat supported by the casing, on which the valve body is seated in the closed position;
With
The steam flow path is
An upstream flow path through which the steam flows in a horizontal direction toward the valve chamber;
A downstream flow path through which the steam flows from the valve chamber,
The downstream channel is
The steam flowing in the vertical direction from the valve chamber flows in a horizontal direction toward the downstream side by flowing along a curved guide surface.
A steam valve characterized by that. The steam flow path is
An upstream channel connected to the valve chamber;
The valve chamber connected to the upstream flow path;
A first downstream channel connected to the valve chamber, and a second downstream channel connected to the first downstream channel,
In the first downstream channel, the steam flows along the curved guide surface,
In the second downstream channel, the steam flows in a horizontal direction.
The steam valve according to claim 1. A valve rod for reciprocating the valve body,
The valve stem passes through the casing and is drawn below the casing;
The steam valve according to claim 2. The casing is
Holding a bush for slidably supporting the valve stem;
The steam valve according to claim 3. The bush has a tip exposed in the first downstream channel,
The tip forms an inclined surface following the curved guide surface;
The steam valve according to claim 4. The bush
It is constituted integrally including the tip, or
It is constituted by a combination of an upper structure including the inclined surface of the tip and a lower structure separate from the upper structure.
The steam valve according to claim 5. The bush
By being accommodated so as to be covered by the casing, it is not exposed to the first downstream channel,
The steam valve according to claim 4.

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