JPH0861519A - Butterfly valve - Google Patents

Abstract

PURPOSE: To make unform the exhaust amount of a refrigerant and cool the inside wall of a valve stem outer pipe uniformly by forming the valve stem from an inner pipe as a circular flow-path and outer pipe as a ring-shaped flow-path, and arranging the axial direction pitch of opening furnished in the valve stem inner pipe so that the pinch becomes denser from the valve element periphery toward the center. CONSTITUTION: A high temp, butterfly valve concerned is used as a gas turbine inlet valve of a pressurized fluid layer type composite power plant etc., wherein a valve stem 26 accommodated in a valve element 24 of butterfly valve is configured with an outer pipe 25, an inner pipe 27a equipped with circular openings 28a..., and a partitioning plate 30 provided in the center of the valve element. The inner pipe 27a is formed so that the axial direction pitches of the circular openings 28a... and openings 29a... arranged in the pipe axial direction and pipe circumferential direction symmetrically about the partitioning plate 30 are denser as approaching the partitioning plate 30 and coarser as going farther from the plate 30. On the inside wall surface of the outer pipe 25, projections 34a... and 35a... are furnished symmetrically about the plate 30 in the middle of the axial direction pitch of the circular openings 28a... in the inner pipe 27a.

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 stem cooling structure suitable for the high temperature butterfly valve.

[0002]

2. Description of the Related Art Recently, in a fluidized bed power plant such as shown in FIG.
And for the purpose of isolating 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 about to be applied to a power plant. Among these hot valves,
In particular, the butterfly valve 9 is required to have a high level of function and reliability in order to urgently shut off the hottest combustion gas at high speed.

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

Further, the valve rod 16 which operates at high speed in high temperature combustion gas has both ends supported by bearings 22a and 22b, but the high temperature strength of the valve rod material is as high as 600 ° C. or higher as shown in FIG. Then, 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 portion of the inside of the valve rod 16 is proposed in Japanese Patent Application No. 3-85669. .

[0005]

However, the above-mentioned known technique does not refer to a technique for improving the performance of valve stem cooling and energy saving of the cooling medium.

That is, it goes without saying that an actual power generation plant requires a cooling system capable of achieving the maximum cooling effect by using the minimum cooling medium in order to increase the thermal efficiency of the plant. Has not taken any measures to increase the cooling effect of the valve stem or reduce the cooling medium. In addition, in the high temperature butterfly valve applied to an actual power plant, the processing amount of combustion gas is enormous, so the valve diameter is considerably large, and the axial length of the valve stem is also lengthened accordingly. Become. Therefore, considering reliability such as thermal stress of the valve rod, a method of cooling the valve rod in the axial direction as uniformly as possible is necessary.

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

[0008]

A first feature of a butterfly valve according to the present invention for achieving the above object is to dispose a heat insulating material layer on an inner circumference of a valve box, and to arrange an inner circumference of the heat insulating material layer. An inner cylinder made of a heat-resistant material is provided in the inner cylinder, and a valve body is provided inside the inner cylinder to rotate around an axis to open and close a flow path. In a butterfly valve provided with a valve rod projecting at, the valve rod is composed of an inner pipe having a circular flow passage and an outer pipe having an annular flow passage, and the inner pipe has a large number in a pipe axial direction and a pipe circumferential direction. A circular opening is provided, and the circular openings are arranged such that the axial arrangement pitch is dense on the valve body center side and coarse on the valve body outer peripheral side, and both ends of the valve rod inner tube are arranged. The cooling medium is introduced into the inner wall of the outer tube from the circular opening of the inner tube so that the cooling medium is jetted and collided with the inner wall of the outer tube.

A second feature of the butterfly valve according to the present invention is that a plurality of projections having a function of a turbulence promoting body are arranged in the axial direction on the inner wall of the outer tube having the annular flow path. The cooling medium is introduced from both ends of the valve rod inner pipe, jetted from the circular opening of the inner pipe to the inner wall of the outer pipe, collided, and brought into contact with the turbulent flow promoting body.

Further, a third feature of the butterfly valve according to the present invention is that an air separating layer having a constant gap is provided between the outer wall of the outer tube having the annular flow passage and the inner wall of the valve body, and the valve is also provided. Circular shape of the inner pipe by arranging a projection having a function of a turbulence promoting body on the inner wall of the outer pipe where the body and the outer shaft of the valve rod come into axial contact This is because the turbulent flow promoting body is brought into contact with the inner wall of the outer tube by jetting from the opening and colliding with it.

Furthermore, a fourth feature of the butterfly valve according to the present invention is that the diameter of the inner pipe tube is set so that the central portion of the valve body is large and the outer peripheral portion of the valve body is gradually reduced. The annular passage formed by the tube axis of the tube and the inner wall of the inner tube is formed by changing the cross-sectional area in the axial direction, and a large number of circular openings are formed in the inner tube in the tube axial direction and the tube circumferential direction. The cooling medium is introduced from both ends of the valve rod inner tube so that the cooling medium is jetted from the circular opening of the inner tube to the inner wall of the outer tube and collided with the cooling medium.

Furthermore, the opening axis angle of the circular opening provided on the inner wall of the valve rod inner pipe is formed so as to be substantially right at the center side of the valve body and gradually changed to an acute angle toward the outer peripheral side of the valve body. You may.

Furthermore, the cooling medium may be discharged from the valve body center side of the annular flow path to the valve body outer circumference side.

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

Furthermore, 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 so that the cooling medium outlet temperature falls within a specified temperature range by using the detected temperature. May be provided.

[0016]

The present invention provides a valve rod cooling system having a high cooling performance by taking the above means, and can contribute to the improvement of reliability of the high temperature butterfly valve and the efficiency improvement of the power generation plant. That is, it is difficult to homogenize the ejection amount of the cooling medium in the axial direction by simply injecting the cooling medium from the opening of the hollow chamber inside the valve rod to cool the inner wall of the valve rod outer tube.
As in the present invention, by arranging the axial pitch of the openings provided in the inner pipe of the valve rod so as to become denser from the outer peripheral portion of the valve body toward the central portion, the discharge amount of the cooling medium, that is, the impingement speed is made uniform. It is possible to cool the inner wall of the valve stem outer tube almost uniformly.

Further, when a turbulent flow promoting body is attached to the inner wall surface of the valve rod outer tube, a turbulent flow promoting effect is exerted during the process in which the jetted cooling medium returns to the outer tube of the annular flow passage, so that the heat of the cooling medium is increased. Communication is further improved. Therefore, according to the means of the present invention,
The superposition effect by impingement cooling and turbulent flow promotion works effectively to cool the valve rod more efficiently.

Further, by providing an air isolation layer having a constant gap between the outer wall of the valve rod outer tube and the inner wall of the valve body,
The isolation layer exerts a heat insulating effect and can suppress heat conduction from the valve body to the valve rod, so that the cooling effect of the cooling medium can be further enhanced.

On the other hand, a pipe shaft whose shaft diameter gradually changes is provided in the inner pipe of the valve rod, and the pipe is arranged so that the flow passage area of the cooling medium flowing through the inner pipe is large at the valve central portion and small at the valve outer peripheral portion. Causes the pressure of the cooling medium to rise from the valve outer periphery toward the center, and even if the openings of the valve rod inner pipes are arranged at the same pitch in the axial direction, the amount of cooling medium ejected from the openings is controlled. The inner wall of the valve stem outer tube can be uniformly impinged in the axial direction.

[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 rod 26 is provided inside the valve body 24 of the butterfly valve.
The valve rod 26 is composed of an outer pipe 25, an inner pipe 27 and a partition plate 30 at the center of the valve body. The inner pipe 27 is symmetrical with respect to the central partition plate 30 in the pipe axial direction and the pipe circumferential direction. A large number of circular openings 28a, 28b, 28c ... And 29a, 29
b, 29c ... Are provided, and the circular openings 28a,
The opening areas of 28b, 28c ... Are almost the same.

However, as described in detail in FIG. 6, the axial pitch of the circular openings provided in the inner pipe 27 becomes denser as it approaches the center of the valve body, that is, the partition plate 30, and as it moves away from the partition plate 30. Arrange roughly. The reason for this will be described in detail later. On the other hand, on the inner wall surface of the outer pipe 25 of the valve rod having the annular flow path, the projections 34a, 34b, 34c ... And 35a, 35 having the function of the turbulence promoting body with the partition plate 30 symmetrical.
b, 35c ... Are attached. The protrusions 35a, 35b, 3
5c ... Circular openings 28a, 28 of the inner tube 27
b, 28c ... Are arranged in the middle of the axial pitch.

The cooling medium for the valve rod is introduced from both ends of the valve rod 26 into the inner pipe 27 as indicated by arrows 31a and 31b, and 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, when the circular openings 28 and 29 are arranged at equal pitches in the axial direction, according to our experiment, as shown in FIG. 7, the temperature T ₀ of the inner wall surface of the outer tube 25 is equal to the valve body. It becomes high at the center side and becomes low at the outer peripheral side of the valve body, and the temperature distribution becomes considerably uneven in the axial direction. Along with this, the heat transfer coefficient α ₀ of the cooling medium is low on the center side of the valve body and high on the outer peripheral side of the valve body. This result shows that the impingement cooling by the circular openings 28 and 29 of the inner pipe 27 should select the cooling structure in consideration of the thermal stress of the valve rod and the uniform cooling performance. .

Therefore, according to the present invention, as described above, the partition plate 30 becomes denser as it approaches the central portion of the valve body, that is, the partition plate 30.
We propose a cooling structure that is arranged more coarsely away from. In this cooling structure, the circular openings 28, 2 are arranged toward the center of the valve body.
It is possible to increase the amount of cooling medium ejected from 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.
_{It is possible to make 1} uniform in the axial direction, and avoid thermal stress on the valve stem and uneven cooling performance.

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

8 to 11 show application examples of the present invention,
It shows a modified embodiment.

FIG. 8 shows another embodiment of the present invention, which is a valve body 2
The inner peripheral portion of 4 and the outer peripheral portion of the outer tube 25 do not come into full contact with each other in the axial direction, and slit-shaped isolation layers 39a, 39b ... Are provided.
This is the case where the valve body 24 and the outer pipe 25 of the valve rod are in partial contact with each other in the axial direction, such as 40a, 40b. As a result, the isolation layer 39 forms an adiabatic layer with air, and the heat flow transmitted by heat conduction from the valve body 24 to the outer pipe 25 of the valve rod can be suppressed, and the valve rod can be protected more reliably.

Further, projections 38a, 38b ... Having a function of a turbulence promoting body are attached to the inner wall surface of the valve rod outer tube 25, which is opposed to the valve bodies 24 and 40a, 40b. Then, the cooling performance of the contact portion between them is improved.

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

In this embodiment, the pipe shafts 41a and 41b are attached inside the inner pipes 27a and 27b, and the shaft diameter of the pipe shaft 41 is made larger on the center side of the valve body and smaller on the outer side of the valve body. It is an example of. Thereby, the inner pipe 27 and the pipe shaft 41
It becomes possible to sequentially change the area of the annular flow passages 41a and 41b formed in 1. in the axial direction.
The pressure of the cooling medium in a and 41b becomes higher toward the center of the valve body.

Therefore, the circular opening 28 of the inner pipe 27,
Even when 29 are arranged at equal pitches in the axial direction, it is possible to increase the amount of the cooling medium ejected from the circular openings 28c and 29c on the center side of the valve body, and prevent nonuniform cooling performance in the axial direction.

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 to the valve body center side and gradually increases toward the valve body outer circumference side. It is an example in the case of changing to an acute angle. As a result, the outer tube 2
The collision jets 45a, 45b, ... To the inner wall surface of 5 can suppress the deflection of the cooling medium discharged from the annular flow path by the cross flow 47, and prevent the cooling performance of the collision jets from being deteriorated.

FIG. 11 shows still another embodiment of the present invention, which is an embodiment relating to the exhaust heat recovery method and the cooling medium amount control method in the pressurized fluidized bed power plant of the valve rod cooling medium described above. The valve rod cooling medium 49 is introduced into the valve rod 16 from an auxiliary compressor or a blower (not shown), and the exhaust cooling medium 52 is guided to the valve box outer peripheral 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 to the steam turbine.
Heat 0,61. Therefore, it is possible to effectively recover the exhaust heat of the cooling medium whose temperature has risen due to the cooling of the valve rod, and it is possible to contribute to the improvement of the thermal efficiency of an applied plant such as a pressurized fluidized bed power plant. On the other hand, as for the amount of cooling medium, the temperature of the cooling medium 52 after cooling the valve rod is detected by a temperature sensor, and cooling is performed so that the above temperature falls within a specified temperature range (that is, a temperature level at which a target cooling performance can be achieved). The opening of the medium flow rate control valve 50 is adjusted to control the amount of cooling medium. This makes it possible to optimize the amount of cooling medium and to perform effective valve stem cooling.

[0035]

As described above, the present invention can provide a system having a higher cooling performance as a valve rod cooling system for a high temperature butterfly valve, and is a new type of the above pressurized fluidized bed combined cycle power plant. It can contribute to the improvement of reliability and efficiency of the high temperature butterfly valve applied to the plant.

[Brief description of drawings]

FIG. 1 is 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 vertical cross-sectional view of a conventional high temperature butterfly valve.

FIG. 4 is a side view of FIG.

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

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

FIG. 7 is a temperature distribution characteristic in the valve rod.

FIG. 8 is 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 a valve stem cooling opening structure 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 ... Exhaust heat recovery feed water heater, 9 ... High temperature butterfly valve, 1
5, 24 ... Valve body, 16, 26 ... Valve rod, 25 ... Outer pipe, 27
... Inner tube, 28, 29 ... Circular opening, 30 ... Partition plate, 32
... Jet of cooling medium, 34, 35 ... Protrusion with turbulence promoting body, 39 ... Air separation layer, 41 ... Pipe axis of valve rod inner tube, 48
... Valve box outer peripheral cooling chamber, 50 ... Cooling medium flow rate control valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Kugenuma 3-2-2 Sachimachi, Hitachi City, Ibaraki Prefecture Hitachi Engineering Service Co., Ltd.

Claims (8)

[Claims] 1. A heat insulating material layer is arranged on the inner circumference of a valve box, an inner cylinder made of a heat-resistant material is arranged on the inner circumference of the heat insulating material layer, and the inner cylinder is rotated around an axis. Has a valve body that opens and closes the flow path by
And in a butterfly valve provided with a valve rod that penetrates the valve body and the valve box and has both ends projecting to the outside, the valve rod is composed of an inner pipe having a circular flow passage and an outer pipe having an annular flow passage, The inner pipe has a large number of circular openings in the pipe axial direction and the pipe circumferential direction, and the circular openings are densely arranged in the axial direction on the valve body center side and coarsely on the valve body outer circumference side. A butterfly valve, wherein the butterfly valve is arranged so that the cooling medium is introduced from both ends of the inner pipe of the valve rod so as to be jetted and collided with the inner wall of the outer pipe from the circular opening of the inner pipe. 2. A heat insulating material layer is arranged on the inner circumference of a valve box, an inner cylinder made of a heat-resistant material is arranged on the inner circumference of the heat insulating material layer, and the inner cylinder is rotated around an axis. Has a valve body that opens and closes the flow path by
And in the butterfly valve provided with a valve rod that penetrates the valve body and the valve box and has both ends protruding to the outside, the valve rod is composed of an inner pipe having a circular flow passage and an outer pipe having an annular flow passage, The inner pipe has a large number of circular openings in the pipe axial direction and the pipe circumferential direction, and the circular openings are densely arranged on the valve body center side in the axial direction and coarsely arranged on the valve body outer peripheral side. And the inner wall of the outer pipe having the annular flow passage is provided with a plurality of projections having the function of turbulence promoting members in the axial direction, and cooling is performed from both ends of the valve rod inner pipe. A butterfly valve, characterized in that a medium is introduced and jetted from the circular opening of the inner pipe to the inner wall of the outer pipe so as to collide with the medium to bring it into contact with the turbulence promoting body. 3. A heat insulating material layer is arranged on the inner circumference of a valve box, an inner cylinder made of a heat resistant material is arranged on the inner circumference of the heat insulating material layer, and the inner cylinder is rotated around an axis. Has a valve body that opens and closes the flow path by
And in the high temperature butterfly valve provided with a valve rod that penetrates the valve body and the valve box and has both ends protruding to the outside, the valve rod is composed of an inner pipe having a circular flow passage and an outer pipe having an annular flow passage. 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. In addition, an air isolation layer having a constant gap is provided between the outer wall of the outer pipe having the annular flow path and the inner wall of the valve body, and the inner wall of the outer pipe in which the valve body and the valve rod outer pipe are in axial contact with each other. A projection having the function of a turbulent flow promoting body is disposed in the portion, and a cooling medium is introduced from both ends of the valve rod inner pipe, jetted from the circular opening of the inner pipe to the inner wall of the outer pipe, and collided to cause the turbulent flow. A butterfly valve characterized by being brought into contact with a promoter. 4. A heat insulating material layer is arranged on the inner circumference of a valve box, an inner cylinder made of a heat-resistant material is arranged on the inner circumference of the heat insulating material layer, and the inner cylinder is rotated about an axis. Has a valve body that opens and closes the flow path by
And in the high temperature butterfly valve provided with a valve rod that penetrates the valve body and the valve box and has both ends protruding to the outside, the valve rod includes an inner pipe having a pipe axis inside the annular flow passage and a double annular flow. It is composed of an outer pipe having a passage, and the diameter of the inner pipe is
The central portion of the valve body is large and gradually reduced toward the outer peripheral side of the valve body, and 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 is changed in the axial direction. And in the inner tube,
Arranging a large number of circular openings in the pipe axis direction and the pipe circumferential direction,
A butterfly valve, characterized in that a cooling medium is introduced from both ends of the valve rod inner pipe so as to be jetted and collided with the inner wall of the outer pipe through the circular opening of the inner pipe. 5. The butterfly valve according to any one of claims 1 to 4, wherein the opening axis angle of the circular opening provided in the inner wall of the valve rod inner tube is substantially right at the valve body center side, A butterfly valve, characterized in that it is formed so as to gradually change to an acute angle toward the outer peripheral side. 6. The butterfly valve according to any one of claims 1 to 5, wherein the cooling medium is discharged from the valve body center side of the annular flow path to the valve body outer peripheral side. Butterfly valve to do. 7. The butterfly valve according to claim 6, wherein:
A butterfly valve, wherein the cooling medium discharged to the outer peripheral side of the valve body is recovered by an exhaust heat recovery feed water heater of a pressurized fluidized bed combined cycle power plant. 8. The butterfly valve according to claim 1, wherein the temperature of the cooling medium discharged to the outer peripheral side of the valve body is detected, and the cooling medium outlet temperature is defined by using the detected temperature. A butterfly valve comprising means for controlling the amount of cooling medium so that the temperature is within the temperature range.