JP3048032B2 - Butterfly valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high temperature butterfly valve structure applied to a gas turbine inlet valve of a pressurized fluidized bed combined cycle power plant or the like, and more particularly to a valve rod cooling structure suitable for the high temperature butterfly valve.

[0002]

2. Description of the Related Art Recently, in a pressurized fluidized-bed power plant as shown in FIG.
In order to isolate the air compressor 2 and the gas turbine 3,
High-temperature valves such as a butterfly valve 9, a compressor discharge valve 10, and a bypass valve 11, which are gas turbine inlet valves, are being applied to power plants. Among these high temperature valves,
In particular, the butterfly valve 9 is required to be highly functional and highly reliable in order to quickly shut off the hottest combustion gas at high speed.

Conventionally, as an emergency shutoff valve applied to such a high-temperature combustion gas, a butterfly valve shown in FIGS. 3 and 4 has been proposed in Japanese Patent Application No. 5-281551. The butterfly valve 9 has a heat insulating member 21 on the inner periphery of the valve box 12 including the flanges 13a and 13b connected to the high-temperature combustion gas pipe.
And an inner cylinder 14. A valve body 15 which is opened and closed by a valve rod 16 is provided inside the inner cylinder 12, and valve seats 17a and 17b provided in the inner cylinder 14 as shown in FIG.
And the valve body 15 come into contact with each other to shut off the combustion gas.

The valve stem 16 which operates at high speed in a high-temperature combustion gas is supported at both ends by bearings 22a and 22b, and the high-temperature strength of the valve stem is 600 ° C. or higher as shown in FIG. , The creep rupture strength is significantly reduced. Therefore, in order to maintain the high-temperature strength of the valve rod material, a method of introducing a cooling medium such as air into the hollow part of the valve rod 16 in a hollow structure has been proposed in Japanese Utility Model Application No. 3-85669. .

[0005]

However, the above-mentioned prior art does not mention a technique for improving the performance of valve stem cooling or energy saving of a cooling medium.

That is, in order to increase the thermal efficiency of the plant, it is needless to say that an actual power generation plant requires a cooling system that can achieve the maximum cooling effect by using the minimum cooling medium. No measures have been taken to increase the cooling effect of the valve stem and to reduce the cooling medium. In addition, the high-temperature butterfly valve applied to an actual power generation plant requires a considerably large valve diameter due to the huge amount of combustion gas to be processed, and the axial length of the valve stem also increases accordingly. Become. Therefore, in consideration of the reliability such as the thermal stress of the valve stem, a method of cooling as uniformly as possible in the axial direction of the valve stem is required.

The present invention has been made in consideration of the above problems, and has as its object to be applied to a pressurized fluidized bed combined cycle power plant and the like, which has higher cooling efficiency and An object of the present invention is to provide a butterfly valve having a structure capable of suppressing generation of thermal stress.

[0008]

A first feature of a butterfly valve according to the present invention for achieving the above object is that a heat insulating material layer is provided on an inner periphery of a valve box, and an inner circumferential surface of the heat insulating material layer is provided. An inner cylinder made of a heat-resistant material is disposed on the inner cylinder. The inner cylinder has a valve body that rotates around an axis to open and close a flow path, and both ends penetrate the valve body and the valve box, and both ends are external. In a butterfly valve provided with a valve stem protruding into the valve, the valve stem is constituted by an inner pipe having a circular flow path and an outer pipe having an annular flow path, and the inner pipe has a large number of pipes in a pipe axial direction and a pipe circumferential direction. With a circular opening, the circular openings are arranged so that the arrangement pitch in the axial direction is dense on the valve body center side and coarse on the valve body outer peripheral side, and both ends of the valve stem inner tube. The cooling medium is introduced from above, and is ejected from the circular opening of the inner tube to the inner wall of the outer tube so as to collide.

[0009] A second feature of the butterfly valve according to the present invention is that a plurality of protrusions having a function of a turbulence promoter are disposed in an axial direction on an inner wall of the outer pipe having the annular flow path. A cooling medium is introduced from both ends of the inner pipe of the valve stem, is jetted from the circular opening of the inner pipe to the inner wall of the outer pipe, and collides with the turbulence promoting body.

A third feature of the butterfly valve according to the present invention is that an air separation layer having a certain gap is provided between the outer wall of the outer tube having the annular flow passage and the inner wall of the valve body, A protrusion having the function of a turbulence promoter is disposed on the inner wall of the outer tube where the body and the valve stem outer tube are in axial contact with each other, and a cooling medium is introduced from both ends of the valve stem inner tube to form a circular inner tube. The reason is that the blast is jetted from the opening to the inner wall of the outer tube and collides with the turbulence promoting body.

Further, a fourth feature of the butterfly valve according to the present invention is that the pipe shaft diameter of the inner pipe is made larger at the center of the valve body and gradually smaller toward the outer peripheral side of the valve body, thereby reducing the inner diameter. The cross-sectional area of the annular flow path formed by the pipe axis of the pipe and the inner wall of the inner pipe is formed by changing the cross-sectional area in the axial direction, and the inner pipe has a large number of circular openings in the pipe axis direction and the pipe circumferential direction. The cooling medium is introduced from both ends of the valve stem inner pipe so that the cooling medium is ejected from the circular opening of the inner pipe and collides with the inner wall of the outer pipe.

Furthermore, the opening axis angle of the circular opening provided on the inner wall of the valve stem inner pipe is formed to be substantially right at the center of the valve body and to be gradually increased toward the outer periphery of the valve body. May be.

Further, the cooling medium may be discharged from the center of the valve body to the outer periphery of the valve body in the annular flow path.

Further, the cooling medium discharged to the outer peripheral side of the valve body may be recovered to a waste heat recovery / feed water heater of the pressurized fluidized bed combined cycle power plant.

Further, means for detecting the temperature of the cooling medium discharged to the outer peripheral side of the valve body and controlling the amount of the cooling medium using the detected temperature so that the cooling medium outlet temperature falls within a specified temperature range. May be provided.

[0016]

The present invention provides a valve cooling system having high cooling performance by taking the above measures, and can contribute to the improvement of the reliability of the high-temperature butterfly valve and the efficiency of the power plant. In other words, it is difficult to equalize the amount of the cooling medium jetted in the axial direction by simply injecting the cooling medium from the opening of the hollow chamber inside the valve stem to cool the inner wall of the valve stem outer tube.
The discharge amount of the cooling medium, that is, the impingement speed is made uniform by arranging the axial pitches of the openings provided in the valve stem inner pipe so as to be denser from the outer peripheral portion toward the central portion as in the present invention. This makes it possible to cool the inner wall of the valve stem outer tube almost uniformly.

Further, when a turbulence promoting member is provided on the inner wall surface of the outer stem of the valve stem, a turbulent flow promoting effect acts in a process in which the cooling medium after jetting returns to the outer pipe of the annular flow passage, and the heat of the cooling medium is increased. Communication is further improved. Therefore, in the means of the present invention,
The superimposition effect of the impingement cooling and the promotion of the turbulent flow effectively acts, so that the valve stem can be cooled more efficiently.

Further, by providing an air separation layer having a certain gap between the outer wall of the valve stem outer tube and the inner wall of the valve body,
The isolation layer provides a heat insulating effect, can suppress heat conduction from the valve body to the valve stem, and can further enhance the cooling effect of the cooling medium.

On the other hand, the inner pipe of the valve stem is provided with a pipe shaft whose diameter gradually changes, and the cooling medium flowing through the inner pipe is arranged so that the flow passage area is large at the center of the valve and small at the outer periphery of the valve. As a result, the pressure of the cooling medium increases from the outer periphery of the valve toward the center, and even if the openings of the inner pipe of the valve stem are arranged at the same pitch in the axial direction, the amount of the cooling medium ejected from the openings is controlled by the axis. In this manner, the impingement cooling can be uniformly performed in the axial direction on the inner wall of the valve stem outer tube.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a high-temperature butterfly valve to which the present invention is applied.

A valve stem 26 is provided inside the valve body 24 of the butterfly valve.
The valve stem 26 is composed of an outer tube 25, an inner tube 27, and a partition plate 30 at the center of the valve body. And a large number of circular openings 28a, 28b, 28c.
b, 29c... are provided, and the circular openings 28a,
The opening areas of 28b, 28c ... are almost the same.

However, the axial pitch of the circular openings provided in the inner tube 27 is, as described in detail in FIG. Arrange coarsely. The reason will be described later in detail. On the other hand, on the inner wall surface of the outer pipe 25 of the valve stem having the annular flow path, the projections 34a, 34b, 34c,...
b, 35c ... are attached. The projections 35a, 35b, 3
5c are circular openings 28a, 28 of the inner tube 27.
are arranged in the middle of the axial pitches of b, 28c.

The cooling medium of the valve stem is introduced into the inner pipe 27 from both ends of the valve stem 26 as shown by arrows 31a and 31b, and is jetted from the circular openings 28 and 29 toward the inner wall surface of the outer pipe 25. The so-called impingement cooling, in which the inner wall surface is cooled by a collision jet of a cooling medium, is performed. However, if the circular opening 28, 29 are arranged at equal pitches in the axial direction, according to our experiments, as shown in FIG. 7, the temperature T ₀ of the inner wall surface of the outer tube 25, the valve body The temperature is high on the center side and low on the outer peripheral side of the valve body, and the temperature distribution becomes considerably uneven in the axial direction. Accordingly, the heat transfer coefficient α ₀ of the cooling medium decreases at the center of the valve body and increases at the outer periphery of the valve body. This result indicates that the cooling structure should be selected in consideration of the thermal stress of the valve stem and the uniform cooling performance in the impingement cooling by the circular openings 28 and 29 of the inner pipe 27. .

Therefore, as described above, according to the present invention, the closer to the center of the valve element, that is, the closer to the partition plate 30, the closer the partition plate 30 is.
We propose a cooling structure that is arranged more coarsely as the distance from the cooling system increases. In the present cooling structure, the circular openings 28, 2 become closer to the center of the valve body.
It is possible to increase the amount of the cooling medium ejected from the nozzle 9, that is, the impingement flow velocity. As a result, as shown in FIG. 7, the temperature T ₁ and the heat transfer coefficient α of the inner wall surface of the outer tube 25 are increased.
₁ can be made uniform in the axial direction, and unevenness in the thermal stress and cooling performance of the valve stem can be avoided.

Further, the projections 34 and 35 attached to the inner wall surface of the outer tube 25 have a function of promoting a turbulent flow such as a vortex flow on the flow of the cooling medium after colliding with the inner wall surface of the outer tube. In addition to the impingement cooling effect by the impinging jet described above, a cooling effect by turbulent forced convection is added,
The cooling performance of the valve stem is further improved.

FIGS. 8 to 11 show application examples of the present invention.
13 shows a modified embodiment.

FIG. 8 shows another embodiment of the present invention.
The inner peripheral portion of the outer tube 4 and the outer peripheral portion of the outer tube 25 are not in contact with each other in the entire axial direction, and slit-shaped isolation layers 39a, 39b.
The valve body 24 and the outer tube 25 of the valve stem are in partial contact with each other in the axial direction as indicated by 40a, 40b, and so on. Thereby, the isolation layer 39 forms a heat insulating layer by air, and can suppress the heat flow transmitted by heat conduction from the valve body 24 to the outer pipe 25 of the valve stem, thereby more reliably protecting the valve stem.

Further, projections 38a, 38b having a turbulence promoting function are provided on the inner wall surface of the valve stem outer tube 25 which faces the valve stem 24 and the valve stem outer tube 25 in contact with the valve stem outer tube 25. Thus, the cooling performance of the contact portion between the two is improved.

FIG. 9 shows still another embodiment of the present invention.

In this embodiment, pipe shafts 41a and 41b are provided inside the inner pipes 27a and 27b, and the diameter of the pipe shaft 41 is large at the center of the valve body and small at the outer periphery of the valve body. This is an embodiment of the present invention. Thereby, the inner pipe 27 and the pipe shaft 41
It is possible to sequentially change the areas of the annular flow paths 41a and 41b formed in the axial direction.
The pressure of the cooling medium at a and 41b increases toward the center of the valve body.

Therefore, the circular openings 28,
Even when the fuel cells 29 are arranged at equal pitches in the axial direction, the amount of the cooling medium ejected from the circular openings 28c and 29c on the valve element center side can be increased, and the cooling performance in the axial direction can be prevented from becoming uneven.

FIG. 10 shows still another embodiment of the present invention, in which the opening axis angle θ of the circular opening provided in the inner pipe 27 is made perpendicular at the center of the valve body, and gradually toward the outer periphery of the valve body. This is an embodiment in a case where the angle is changed to an acute angle. Thereby, the outer tube 2
5 can be suppressed from being deflected by the cross flow 47 of the cooling medium discharged from the annular flow path, and the cooling performance of the collision jet can be prevented.

FIG. 11 shows still another embodiment of the present invention, which relates to a method of recovering exhaust heat and a method of controlling the amount of cooling medium in a pressurized fluidized-bed power plant using a valve rod cooling medium. The valve stem cooling medium 49 is introduced into the valve stem 16 from an auxiliary compressor or a blower (not shown), and the exhaust cooling medium 52 is guided to the valve box outer peripheral part cooling chamber 48. Further, the cooling medium 56 after cooling the valve box in the valve box outer peripheral cooling chamber 48 is introduced into the exhaust heat recovery feed water heater 8 and mixed with the exhaust gas 58 from the gas turbine to supply water 6 for the steam turbine.
Heat 0,61. Therefore, the exhaust heat of the cooling medium whose temperature has increased due to the cooling of the valve stem can be effectively recovered, which can contribute to the improvement of the thermal efficiency of an applied plant such as a pressurized fluidized-bed power plant. On the other hand, the amount of the cooling medium is detected by a temperature sensor of the temperature of the cooling medium 52 after cooling the valve stem, and the cooling medium is cooled so that the above-mentioned temperature falls within a specified temperature range (that is, a temperature level at which a target cooling performance can be achieved). The opening degree of the medium flow control valve 50 is adjusted to control the amount of the cooling medium. This makes it possible to optimize the amount of cooling medium and perform effective valve stem cooling.

[0035]

As described above, the present invention can provide a cooling system having a higher cooling performance as a valve stem cooling system for a high-temperature butterfly valve. This can contribute to the improvement of the reliability and the efficiency of the high-temperature butterfly valve applied to the plant.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a butterfly valve to which the present invention is applied.

FIG. 2 is a typical example of a conventional pressurized fluidized bed combined cycle power plant.

FIG. 3 is a longitudinal sectional view of a conventional high-temperature butterfly valve.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is an explanatory diagram of high-temperature strength characteristics of a valve material.

FIG. 6 is an explanatory view of the operation of cooling the stem of the high-temperature butterfly valve of the present invention.

FIG. 7 shows temperature distribution characteristics in a valve stem.

FIG. 8 shows a valve stem cooling structure according to another embodiment of the present invention.

FIG. 9 is a valve stem cooling structure according to another embodiment of the present invention.

FIG. 10 is an opening structure of a valve stem cooling according to another embodiment of the present invention.

FIG. 11 is a cooling medium recovery method and control system to which the present invention is applied.

[Explanation of symbols]

8: Waste heat recovery feed water heater, 9: High temperature butterfly valve, 1
5, 24: valve body, 16, 26: valve stem, 25: outer tube, 27
... inner pipe, 28, 29 ... circular opening, 30 ... partition plate, 32
... jet of cooling medium, 34, 35 ... projection with turbulence promoting body, 39 ... air separation layer, 41 ... tube axis of valve stem inner tube, 48
... Valve box outer peripheral cooling chamber, 50... Cooling medium flow control valve.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shuichi Kukunuma 3-2-2, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi Engineering Services Co., Ltd. (56) References Mikai Sho53-148331 (JP, U) Kaihei 3-36170 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) F16K 1/16-1/54 F16K 49/00 F16K 51/00

Claims (8)

(57) [Claims] 1. A heat insulating material layer is provided on an inner periphery of a valve box, an inner cylinder made of a heat-resistant material is provided on an inner periphery of the heat insulating material layer, and the inner cylinder is rotated around an axis. Having a valve body that opens and closes the flow path,
And in a butterfly valve provided with a valve stem that penetrates the valve body and the valve box and both ends protrude to the outside, the valve stem is configured by an inner pipe having a circular flow path and an outer pipe having an annular flow path, The inner pipe has a number of circular openings in the pipe axis direction and the pipe circumferential direction, and the circular openings are arranged such that the axial arrangement pitch is dense on the valve element center side and coarse on the valve element outer peripheral side. A butterfly valve, wherein a cooling medium is introduced from both ends of the valve stem inner pipe so that the cooling medium is ejected from the circular opening of the inner pipe to the inner wall of the outer pipe to collide with the butterfly valve. 2. A heat insulating material layer is disposed on the inner periphery of the valve box, an inner cylinder made of a heat-resistant material is disposed on the inner periphery of the heat insulating layer, and the inner cylinder is rotated around an axis. Having a valve body that opens and closes the flow path,
And in a butterfly valve provided with a valve stem that penetrates the valve body and the valve box and both ends protrude to the outside, the valve stem is configured by an inner pipe having a circular flow path and an outer pipe having an annular flow path, The inner pipe has a number of circular openings in the pipe axis direction and the pipe circumferential direction, and the circular openings are arranged such that the axial arrangement pitch is dense at the valve element center side and rough at the valve element outer peripheral side. And a plurality of projections having the function of a plurality of turbulence promoters in the axial direction are disposed on the inner wall of the outer pipe having the annular flow path, and cooling is performed from both ends of the valve stem inner pipe. A butterfly valve, wherein a medium is introduced, and is ejected from the circular opening of the inner tube to the inner wall of the outer tube so as to collide with the medium and come into contact with the turbulence promoter. 3. A heat insulating material layer is disposed on the inner periphery of the valve box, an inner cylinder made of a heat-resistant material is disposed on the inner periphery of the heat insulating layer, and the inner cylinder is rotated around an axis. Having a valve body that opens and closes the flow path,
And in the high-temperature butterfly valve provided with a valve stem that penetrates the valve body and the valve box and both ends protrude to the outside, the valve stem includes an inner pipe having a circular flow path and an outer pipe having an annular flow path. The inner pipe has a large number of circular openings in the pipe axial direction and the pipe circumferential direction, and is arranged so that the axial arrangement pitch is dense on the valve body center side and coarse on the valve body outer peripheral side. Further, an air separation layer having a certain gap is provided between the outer wall of the outer tube having the annular flow path and the inner wall of the valve body, and the inner wall of the outer tube in which the valve body and the valve stem outer tube are in axial contact with each other. A protrusion having the function of a turbulence promoter is disposed in the portion, and a cooling medium is introduced from both ends of the valve stem inner pipe, and is ejected from the circular opening of the inner pipe to the inner wall of the outer pipe to collide with the turbulent flow. A butterfly valve, wherein the butterfly valve is brought into contact with an accelerator. 4. A heat insulating material layer is provided on the inner periphery of the valve box, an inner cylinder made of a heat-resistant material is provided on the inner periphery of the heat insulating material layer, and the inner cylinder is rotated around an axis. Having a valve body that opens and closes the flow path,
And a high-temperature butterfly valve provided with a valve stem penetrating the valve body and the valve box and projecting outward at both ends, wherein the valve stem includes an inner pipe having a pipe shaft inside the annular flow path and a double annular flow. The outer tube having a passage, the inner tube diameter of the inner tube,
The central portion of the valve body is large, and is gradually reduced toward the outer peripheral side of the valve body, and is formed by changing the cross-sectional area of the annular flow path formed by the pipe axis of the inner pipe and the inner wall of the inner pipe in the axial direction. , And in the inner tube,
Arrange a large number of circular openings in the pipe axis direction and pipe circumferential direction,
A butterfly valve, wherein a cooling medium is introduced from both ends of the valve stem inner pipe so as to be ejected from the circular opening of the inner pipe to the inner wall of the outer pipe to collide therewith. 5. The butterfly valve according to claim 1, wherein an opening axis angle of a circular opening provided on an inner wall of the valve stem inner pipe is substantially perpendicular to a center of the valve body. A butterfly valve formed so as to gradually change its acute angle toward a body outer peripheral side. 6. The butterfly valve according to claim 1, wherein the cooling medium is discharged from a center of the valve body of the annular flow path to an outer peripheral side of the valve body. Butterfly valve. 7. The butterfly valve according to claim 6, wherein
The butterfly valve is characterized in that the cooling medium discharged to the outer peripheral side of the valve body is collected in an exhaust heat recovery / feed water heater of the pressurized fluidized bed combined cycle power plant. 8. The butterfly valve according to claim 1, wherein a temperature of the cooling medium discharged to an outer peripheral side of the valve body is detected, and the temperature of the cooling medium outlet is defined using the detected temperature. A means for controlling the amount of the cooling medium so as to fall within the temperature range described above.