JPH07301366A - Butterfly valve - Google Patents

Abstract

(57) [Abstract] [Purpose] Pressurized fluidized bed boiler combined cycle power plant (PFB)
In C), an object is to provide an appropriate cooling system for a valve rod of a butterfly valve used as a control valve and a stop valve for high-temperature (about 900 ° C.) combustion gas flowing from a boiler outlet to a gas turbine. [Structure] The valve rod is a double hollow tube, low-temperature fluid (air) is supplied from both ends of the valve rod, and a return flow is made at an intermediate point of the valve rod. . The bearing portion is also cooled by providing another cooling passage. [Effect] By the return flow type impingement cooling, efficient cooling can be performed, high thermal efficiency is possible, and a normal Co-based or Ni-based alloy valve rod can be used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to high temperature fluids, especially 800 ° C.
The present invention relates to a butterfly valve for controlling combustion gas, and more particularly to a butterfly valve having a structure for cooling the valve rod portion and the bearing for supporting the valve rod, which are severe in high temperature strength.

[0002]

2. Description of the Related Art Butterfly valves are industrially used in various fields, but the temperature of the working fluid is lower than the combustion gas temperature and is used at 600 ° C. or lower. Therefore, a high temperature material such as Cr-Mo steel or Cr-M is used for the material of the valve rod or the valve body.
If o-V steel or the like was used, it could be used without problems in terms of high temperature strength.

Although it was possible to use an inexpensive material by using a cooling structure, the increase in equipment cost and the increase in operation and maintenance cost due to the adoption of a complicated structure are relatively large, and the cooling structure is in full swing. It was not developed.

[0004]

With the progress of engineering technology, a valve for controlling a high temperature fluid has become one of the important devices. It is considered that raising the temperature is one of the most effective methods for improving the thermal efficiency, but the maximum temperature in the heat cycle is 600 ° C. or less in the ordinary boiler. On the other hand, in a combined cycle power plant combining a pressurized fluidized bed boiler, a gas turbine, and a steam turbine, which have been developed in recent years, the temperature of the combustion gas at the boiler outlet is about 900 ° C. The gas flow rate is also large in large capacity power plants. In this case, providing a butterfly valve in the middle of the large-diameter gas pipe is considered to be one of the suitable methods.

When the combustion gas at 900 ° C. passes through the butterfly valve, the high temperature strength of the valve body, the valve rod, the valve casing, and the bearing for supporting the valve rod becomes a problem, but the valve body and the valve casing have a high temperature resistant casting alloy. For example, a Cr-Ni alloy can be used, but since the valve rod that supports the valve body is a strength member and has a sliding portion, it is difficult to use a high temperature casting, and a nickel-base heat-resistant alloy or the like is used. However, it is necessary to lower the metal temperature by cooling. Similarly, a bearing portion having sliding uses a nickel-base heat-resistant alloy or the like, but needs cooling. Also, when cooling fluid is introduced from one side of the valve rod to cool the valve rod, the cooling fluid becomes hot at the outlet of the valve rod due to the amount of heat entering from the valve body, and other parts such as the valve rod and the valve body. The temperature is such that the bearing, which has a relatively low strength against heat, will be seized. Therefore, it is necessary to cool the bearing portion as well, and it is necessary to consider that the heat quantity of the fluid that has cooled the valve rod and the valve body does not affect the bearing portion.

Further, as a low temperature fluid for cooling the valve rod and the bearing portion, one which is relatively easy to obtain and inexpensive is required, and for cooling the valve rod, almost all of the valve rod is required. It is necessary to uniformly cool and prevent the generation of excessive thermal stress. At the same time, it has become important to increase the cooling efficiency and control the flow rate of the cooling fluid to prevent increase in equipment cost and operating cost.

The present invention has been made in view of the above problems, and an object thereof is to efficiently cool the valve rod and the bearing portion and maintain the strength of the valve rod and the bearing portion. It is to provide a butterfly valve having a suitable cooling structure.

[0008]

A first feature of a butterfly valve according to the present invention for achieving the above object is to make a valve rod hollow and to pass this hollow portion through an axial center portion of the valve rod. 1 hollow part and a double hollow part consisting of an annular second hollow part located on the outer peripheral side of the first hollow part, wherein the second hollow part is the bearing part and the central part of the valve rod. A partition plate that divides is provided, and a communication hole that communicates the first and second hollow portions is provided at least in the vicinity of the central portion of the valve rod and in the vicinity of the bearing portion. Fluid is supplied to the first hollow portion, and the fluid flowing through the first hollow portion is caused to flow into the second hollow portion through the communication hole, so that the valve rod central portion and the bearing portion are respectively provided. It is configured such that it is independently cooled and then discharged to the outside of the valve rod.

A second feature of the butterfly valve according to the present invention is that the valve rod is hollow and the hollow portion is a first hollow portion passing through the axial center portion of the valve rod and the first hollow portion. A double hollow portion formed of an annular second hollow portion located on the outer peripheral side of
A plurality of communication holes that communicate the first and second hollow portions are provided, and a fluid is supplied from both ends of the valve rod to the first hollow portion, and a fluid flowing through the first hollow portion is supplied. The valve rod is cooled by being jetted from the communication hole to the second hollow portion.

Further, a third feature of the butterfly valve according to the present invention is that the valve rod is hollow and the hollow portion is a first hollow portion passing through the axial center portion of the valve rod and the first hollow portion. A double hollow portion formed of an annular second hollow portion located on the outer peripheral side of
A plurality of communication holes that communicate the first and second hollow portions are provided, and a fluid is supplied from both ends of the valve rod to the second hollow portion, and a fluid flowing through the second hollow portion is supplied. The first hollow portion is allowed to flow through the communication hole and flow out from both end portions of the valve rod.

Furthermore, the fluid may be compressed air.

[0012]

According to the above-mentioned first feature of the present invention, the fluid supplied from both ends of the valve rod passes through the first hollow portion and is passed through the communication holes in the vicinity of the central portion of the valve rod and in the vicinity of the bearing portion. The second hollow portion is divided into the valve rod central portion and the shaft bristles, and the fluid passing through the divided second hollow portion separates the valve rod and the bearing portion from each other. Since it is cooled and discharged to the outside of the valve rod, the fluid heated by cooling the valve rod at the central portion of the valve rod does not flow into the bearing portion to heat the bearing portion. At the same time, since the bearing is also cooled, it is possible to protect the bearing, which has a relatively low thermal strength compared to the valve rod, and to control the butterfly valve (rotation) due to seizure or deformation of the bearing. ) It is possible to prevent the impossible state. Moreover, since the hollow portion is doubled, the flow passage area near the side wall of the valve rod can be made annular so that the flow passage area can be narrowed and the flow velocity of the fluid can be increased to efficiently cool the valve rod and the bearing portion. be able to.

According to the second feature of the present invention, the first feature
Since the fluid is ejected from the hollow portion of the valve toward the second hollow portion, the cooling medium can directly collide with the inner wall surface of the valve rod, and the cooling efficiency can be improved.

Further, according to the third feature of the present invention, the fluid is made to flow from the outer hollow portion of the double hollow portion, and the fluid for cooling the valve rod is made to flow from the inner hollow portion thereof. Therefore, the fluid heated by cooling the valve rod does not come into direct contact with the inner wall surface of the bearing portion, and the heating of the bearing portion can be suppressed.

[0015]

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

1 and 2 show the structure of a butterfly valve according to an embodiment of the present invention. Although the valve body 2 controls the high temperature combustion gas 12, the valve body 2 becomes high temperature by heat transfer from the high temperature combustion gas. In a combined cycle power plant that combines a gas turbine, a steam turbine, and a pressurized fluidized bed boiler, the combustion gas temperature is about 900 ° C, and the valve body is also exposed to high temperatures. The valve body 2 is attached to the valve rod 3, and the valve rod also becomes high temperature mainly due to heat transfer from the valve body. In addition, bearings 4 are provided on both ends of the valve rod 3.
Is provided, and the valve body 2 and the valve rod 3 are rotatably supported. In order to cool the valve rod 3 and the bearing portion 4, from the valve rod / bearing cooling air inlets 5 at both ends of the valve rod 3, 1
Supply cooling air at a temperature of 00 ° C or less.

A specific cooling structure for the valve rod will be described with reference to FIG.

FIG. 3 is a cross-sectional view of a butterfly valve having a cooling structure according to an embodiment of the present invention, showing one cross section of the valve rod 3 which is divided into two parts from its central portion.

As shown in FIG. 3, the valve rod has a double hollow structure, and this double hollow structure has a first hollow portion 102 passing through a substantially central axis of the valve rod and the first hollow portion 102. It has a second hollow portion 101 on the outer periphery. Then, when cooling the valve rod 3 and the bearing portion 4, from both ends of the valve rod 3 (in FIG. 3, the structure of half of them is shown. The structure of the other half not shown is the same as that shown in FIG. The following description of other examples is also the same as that of Fig. 3.) Compressed low temperature air is introduced into the inner hollow portion which is the first hollow portion 102.
A part of this cooling air passes through the communication hole 103, is provided in the middle of the second hollow portion 101, and is divided by the partition plate 100 that divides the second hollow portion into a valve pair cooling portion and a bearing cooling portion. The flow is blocked, and the bearing cooling air reversal flow 17 is formed, which cools the bearing portion 4 and the opposing valve rod portion, and is discharged from the bearing cooling air outlet 6. The remaining cooling air passes through the communication hole 104 in the vicinity of the valve body center line 18, becomes the valve rod cooling air reversal flow 14, mainly cools the valve body supporting portion of the valve rod 3, and is discharged from the valve rod cooling air outlet 7. To be done.

As can be seen from the above description and FIG. 3, in this embodiment, the partition plate 100 independently cools the central portion of the valve rod and the bearing portion by the fluid flowing through the second hollow portion 101. Therefore, the valve stem cooling air reversal flow 14 that has become high temperature by cooling the central portion of the valve stem does not reach the bearing part 4 and heat the bearing part 4, and the bearing part 4 is preferably cooled. Can be protected.

Further, the cooling of both the central portion of the valve rod and the bearing portion is a return flow type cooling, and since the low temperature air before cooling and the high temperature air after cooling exchange heat, relatively uniform cooling is possible, and Even if low temperature air of 50 ° C. is used, the temperature of the cooling air rises, the temperature difference from the combustion gas temperature of 900 ° C. can be reduced, and the thermal stress can be reduced. As the cooling fluid, compressed air, which is inexpensive and easily available from the viewpoint of equipment, was used. In a pressurized fluidized bed boiler combined cycle power plant, it is possible to obtain the required air amount from the intermediate stage of the compressor in the gas turbine equipment.
Also, two cooling air outlets, a bearing cooling air outlet and a valve rod cooling air outlet, are provided to cool the bearing portion of the valve rod and the valve body support portion independently.

Another embodiment of the present invention is shown in FIG. The difference from the above-mentioned embodiment is that the impingement return flow system is adopted for cooling the valve rod of the valve body support part and the cooling performance is improved. First hollow part 1 of double hollow structure valve rod
02 and the second hollow portion 101 are provided with a plurality of small holes 16 for collision cooling, which are communication holes, and cooling air is supplied from both ends of the valve rod 3 from the first hollow portion 102 and ejected from this small diameter hole. The impingement cooling is performed by causing the cooling air to collide with the inner wall of the valve rod 3 by the collision air flow 15. This impingement cooling improves the cooling performance, so that the amount of cooling air can be reduced or the valve stem temperature can be further lowered. Further, similarly to the embodiment described with reference to FIG. 3, in this embodiment, the partition plate 100 is provided in the second hollow portion 101 to divide the bearing cooling portion and the cooling portion in the central portion of the valve rod into independent parts. If cooled, the bearing can be protected. Further, although not shown, the collision cooling small diameter hole 16 may be provided in the vicinity of the bearing portion, and in this case, the cooling efficiency of the bearing portion can be further improved.

Another embodiment of the present invention is shown in FIG. In this embodiment, the cooling structure is simplified as compared with the above two embodiments. In this embodiment, the cooling air is supplied from both ends of the valve rod 3 from the second hollow portion 101, so that the bearing portion 4 and the valve rod 3 are provided.
The cooling air that has cooled the air is discharged from the first hollow portion 102 to the outside of the valve rod 3 from both ends of the valve rod 3 through the communication hole 104. As described above, the present embodiment is characterized in that the bearing portion 4 of the valve rod 3 and the valve body support portion that is the central portion of the valve rod are cooled in the same cooling path. In this case, the bearing portion 4 and the valve body support portion are provided in the same cooling path, but the cooling air that has become high temperature due to cooling in the central portion of the valve rod is on the inner peripheral side of the second hollow portion. Since the air flows through the first hollow portion, the amount of heat of the cooling air that has cooled the valve body support portion is equal to the second hollow portion 10
The cooling air flowing through 1 prevents transmission to the bearing portion 4. Therefore, the bearing portion 4 is not heated by the cooling air that has become high temperature by cooling the valve body support portion. In terms of cooling the bearing portion 4 and the valve body support portion and cooling the valve body support portion to protect the bearing portion 4 from the high temperature cooling air, the bearing portion 4 is more protected than the embodiment described with reference to FIGS. 3 and 4. It can be implemented with a simple configuration.

Further, by changing the valve stem portion and adding air pipes connected to both ends of the valve stem, it can be used for remodeling an existing butterfly valve. The structure for cooling as a return flow near the valve rod intermediate point is the same as that of the above-mentioned embodiment.

[0025]

By adopting the forced cooling type butterfly valve of the present invention, it is possible to control the flow rate of a high temperature fluid, for example, combustion gas at 900 ° C. or higher. Inexpensive and easily available air can be used as a low temperature fluid for cooling,
And in the pressurized fluidized bed boiler combined cycle power plant,
It is possible to use compressed air of the gas turbine, which is a component device, and it is possible to cool economically. In addition, the use of a double hollow valve rod has made it possible to achieve more uniform cooling by using a return flow type cooling system.
Further, the impingement cooling by ejecting the cooling fluid from the double pipe inner cylinder portion can further improve the cooling performance.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a butterfly valve according to an embodiment of the present invention.

FIG. 2 is an axial side view of a butterfly valve according to an embodiment of the present invention.

FIG. 3 is a valve rod cooling structure diagram of an embodiment of the present invention.

FIG. 4 is a valve rod cooling structure diagram of another embodiment of the present invention.

FIG. 5 is a valve rod cooling structure diagram of another embodiment of the present invention.

[Explanation of symbols]

1 ... Valve casing, 2 ... Valve body, 3 ... Valve rod, 4 ... Bearing part,
5 ... Valve rod / bearing cooling air inlet, 6 ... Bearing cooling air outlet,
7 ... Valve rod cooling air outlet, 8 ... Hydraulic cylinder, 9 ... Inner valve casing, 10 ... Outer valve casing, 11 ... Insulating material,
12 ... High temperature combustion gas, 13 ... Valve rod / bearing cooling air outlet,
14 ... Valve rod cooling air reverse flow, 15 ... Colliding air flow, 16 ...
Small diameter hole for collision cooling, 17 ... Bearing cooling air reverse flow, 18 ...
Valve body center line, 100 ... Partition plate.

Front page continued (72) Inventor Haruo Urushiya 3-1-1, Saiwaicho, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Shuichi Kugenuma 3--2, Saiwaicho, Hitachi, Ibaraki No. Stock Company Hitachi Engineering Service

Claims (4)

[Claims] 1. A butterfly valve, which is disposed in the middle of a flow path through which a high-temperature fluid flows, and in which bearing portions at both ends of the valve rod are rotatably supported so as to control the flow rate of the high-temperature fluid.
A butterfly valve configured to cool the valve rod by hollowing the valve rod and allowing a fluid to flow through the hollow portion, wherein the hollow portion is a first hollow portion passing through an axial center portion of the valve rod. And a partition plate that divides the second hollow portion into the bearing portion and the central portion of the valve rod, the double hollow portion including an annular second hollow portion located on the outer peripheral side of the first hollow portion. And a communication hole for communicating the first and second hollow portions is provided at least in the vicinity of the central portion of the valve rod and in the vicinity of the bearing portion, and the first hollow portion is provided from both end portions of the valve rod. To the second hollow portion through the communication hole to cool the valve rod central portion and the bearing portion independently of each other. Butter tough, characterized in that it is configured to be discharged to the outside of the valve rod after Lie valve. 2. A butterfly valve for controlling the flow rate of the high temperature fluid, which is arranged in the middle of a flow path for the high temperature fluid, wherein the valve rod is hollow, and the fluid is flowed through the hollow portion. In a butterfly valve configured to cool a rod, the hollow portion includes a first hollow portion that passes through an axial center portion of the valve rod and an annular second portion that is located on an outer peripheral side of the first hollow portion. A double hollow portion formed of a hollow portion is provided with a plurality of communication holes for communicating the first and second hollow portions, and a fluid is supplied to the first hollow portion from both ends of the valve rod. A butterfly valve, characterized in that a fluid flowing through the first hollow portion is jetted from the communication hole to the second hollow portion to cool the valve rod. 3. A butterfly valve, which is disposed in the middle of a flow path through which a high temperature fluid flows, and in which bearing portions at both ends of the valve rod are rotatably supported so as to control the flow rate of the high temperature fluid.
A butterfly valve configured to cool the valve rod by hollowing the valve rod and allowing a fluid to flow through the hollow portion, wherein the hollow portion is a first hollow portion passing through an axial center portion of the valve rod. And a double hollow portion composed of an annular second hollow portion located on the outer peripheral side of the first hollow portion, a plurality of communication holes communicating the first and second hollow portions, and the valve A fluid is supplied to the second hollow portion from both ends of the rod, and the fluid flowing through the second hollow portion is passed through the communication hole to the first
A butterfly valve, characterized in that the butterfly valve is made to flow through the hollow part of the valve and flow out from both ends of the valve rod. 4. The butterfly valve according to any one of claims 1 to 3, wherein the fluid is compressed air.