JPH09196189A - Butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a butterfly valve which prevents thermally symmetric unbalance, and is compact in size and excellent in the shutoff property. SOLUTION: A valve box 23 and an inner cylinder 24 are formed so that the valve box 23 is provided with a radially projected valve box flange 28 on an inner circumferential surface, the inner cylinder 24 is provided with a radially projected inner cylinder flange 29 on an outer circumferential surface, the valve box flange 28 and the inner cylinder flange 29 are provided with a curved part along the outer circumference of a valve stem 26, and the valve box flange 28 and the inner cylinder flange 29 are located opposite to each other through the axis of the valve stem 26. The flanges 28, 29 are lapped and connected to each other in a long hole along the radial direction by bolts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve, and more particularly to a butterfly valve for high temperature used for controlling a hot gas flow.

[0002]

2. Description of the Related Art Conventionally, as a butterfly valve used for controlling a high temperature gas flow of about 650 to 750.degree. In the butterfly valve 1, a heat insulating material layer 4 having a predetermined thickness is arranged on the inner circumference of a valve box 3 having connection flanges 2 projecting on the outer circumferences of both ends, and an inner cylinder 5 made of a heat resistant material is provided on the inner circumference of the heat insulating material layer 4. Is arranged concentrically with the valve box 3, and a disc-shaped valve body 6 capable of opening and closing the flow path is arranged at a central position in the inner cylinder 5 in the axial direction. The valve body 6 is fixed to a valve rod 7 which is provided in a direction perpendicular to the axis of the valve box 3 and the inner cylinder 5 and rotates around the axis.

From the axial center position of the valve rod 7 to the valve box 3 and the inner cylinder 5
At a position spaced a proper distance in the axial direction of the flange 8, a flange 8 is provided so as to project from the inner circumference of the valve box 3, and a flange 9 that overlaps with the outer surface of the flange 8 is provided so as to project on the outer circumference of the inner cylinder 5. 8 and 9 are fastened to each other by bolts with a gasket 10 also serving as a sliding material interposed between the overlapping surfaces, whereby the inner cylinder 5 is supported by the valve box 3. The flanges 8 and 9 are formed continuously in an annular shape because they do not interfere with the penetration portion of the valve box 3 and the valve rod 7 of the inner cylinder 5.

On the inner circumference of the inner cylinder 5, there is formed a valve seat projection 11 with which the outer peripheral edge of the valve body 6 comes into close contact when the valve body 6 is placed in the closed position. A holding plate 12 is provided on the inner circumference so as to prevent the heat insulating material layer 4 from falling out. At the axial center of the valve rod 7, a cylindrical refrigerant passage 13 having a small flow passage cross-sectional area is formed by disposing a round rod or a pipe in the center of the passage having a round hole shape.

With such a structure, the heat insulating material layer 4 arranged on the inner circumference of the valve box 3 insulates the valve box 3 from the high temperature internal fluid, so that the strength of the valve box 3 can be increased without lowering the thermal efficiency. The inner cylinder 5 which is secured and arranged on the inner circumference of the heat insulating material layer 4 prevents the heat insulating material from flowing downstream due to the flow of the internal fluid.

Further, the flanges 8 and 9 projecting from the valve box 3 and the inner cylinder 5 are overlapped and connected to each other, so that a difference in thermal expansion between the valve box 3 and the inner cylinder 5 is caused by a slip between the overlapping surfaces. The difference in thermal expansion is absorbed more smoothly by absorbing and absorbing the gasket 10 also as a sliding material between the overlapping surfaces.

In addition to the butterfly valve 1 as described above, at the axial center position of the valve rod, a partially cutout flange projecting on the inner circumference of the valve box and a partially cutout flange projecting on the outer circumference of the inner cylinder are provided. A butterfly valve adapted to be polymerized is also proposed.
In this butterfly valve, at a position shifted from the axial center position of the valve stem in the axial direction of the valve box and the inner cylinder by an appropriate distance, a structure such as connecting the inner cylinder and the valve box with a flexible joint is used to improve the shutoff property. I have to.

[0008]

However, the annular flange on the inner circumference of the valve box and the annular flange on the outer circumference of the inner cylinder are located at a position displaced from the axial center position of the valve rod in the axial direction of the valve box and the inner cylinder by an appropriate distance. In the case of a butterfly valve configured to be superposed, there is a problem that the thermal symmetry is broken and the valve element does not come into close contact with the valve seat protrusion when the flow path is fully closed.

Further, in the case of a butterfly valve in which a partially cutout flange on the inner circumference of the valve box and a partially cutout flange on the outer circumference of the inner cylinder are overlapped with each other at the axial center position of the valve stem, the shut-off structure becomes large. was there.

The present invention solves the above problems, and an object of the present invention is to provide a butterfly valve which is compact and has a high shutoff property without causing thermal symmetry collapse.

[0011]

In order to solve the above problems, a butterfly valve according to claim 1 of the present invention has a valve box and an inner cylinder arranged concentrically, and a space between the valve box and the inner cylinder. In a butterfly valve having a disk-shaped valve body that is provided with a heat insulating material layer and that rotates around the axis of the valve rod to open and close the flow path in the inner cylinder, the valve box is arranged in a radial direction. The inner cylinder has a protruding valve box flange on the inner peripheral surface, and the inner cylinder has an inner cylinder flange that protrudes in the radial direction on the outer peripheral surface, and the valve box flange and the inner cylinder flange are on the outer circumference of the valve rod. It has a curved portion along the axis of the valve rod and is positioned opposite to each other via the axial center of the valve rod. The flanges are overlapped with each other, and bolts are connected to the slots in the radial direction.

A butterfly valve according to a second aspect of the present invention is such that a sliding member is interposed between the overlapping surfaces of the valve box flange and the inner cylinder flange. In the butterfly valve according to a third aspect of the present invention, a sealing material that seals between the valve box and the inner cylinder is arranged over the entire circumference of the inner cylinder.

In a butterfly valve according to a fourth aspect of the present invention, a flange seal seat portion which is opposed to each other in the radial direction is formed on each of the valve box flange and the inner cylinder flange, and the flange seal seat portion is supported by both flange seal seat portions and is radially supported. A sealing material having expandability is provided.

In the butterfly valve according to a fifth aspect of the present invention, the sealing material has a plurality of frustoconical cylinders having different diameters arranged concentrically and in opposite directions, and a bottom end edge of the inner frustoconical cylinder. And a head end edge of the outer frustoconical cylinder body are welded to each other, and a notch along the outer peripheral surface of the valve stem is provided at a portion facing the valve stem, and the end of the outermost frustoconical cylinder body is provided. And the end of the innermost frustoconical cylinder body are welded to the valve box flange and the inner cylinder flange.

In the butterfly valve according to the sixth aspect, the sealing material is formed of a thin plate material. According to the configuration of claim 1, in a state where the heat insulation layer does not reduce the thermal efficiency and the strength of the valve box is secured, and the inner cylinder prevents the heat insulation material from flowing downstream by the internal fluid, The difference in thermal expansion in the radial direction due to the temperature of the inner cylinder becoming higher than the temperature of the valve box is easily absorbed by the valve box flange and the inner tube flange sliding on each other on the overlapping surface. At this time, since the valve box flange and the inner cylinder flange are located opposite to each other with the axis of the valve rod in between, the thermal symmetry is not broken and the valve body and the valve are fully closed when the flow path is fully closed. The close contact with the seat protrusion is secured.

According to the second aspect of the present invention, the sliding member improves the sliding between the flanges, and the difference in thermal expansion is more easily absorbed. According to the configuration of claim 3, since the sealing material that seals between the valve box and the inner cylinder is arranged over the entire circumference of the inner cylinder, the internal fluid is provided in the heat insulating material layer between the valve box and the inner cylinder. Even when the gas flows in, it is blocked by the sealing material and does not flow further than this butterfly valve. Also, the sealing material itself becomes compact.

According to the structure described in claim 4, since the flange seal seat portion is formed, the seal material can be easily installed, and the seal material has expandability in the radial direction, so that thermal expansion Only relatively low stress occurs at times.

According to the fifth aspect of the present invention, the sealing material formed by welding the bottom end edge of the inner truncated conical cylinder body and the head end edge of the outer truncated conical cylinder body in the radial direction is used. It has expandability, and relatively low stress is generated even during thermal expansion.

According to the sixth aspect of the invention, the sealing material made of a thin plate material has a gentle temperature gradient between the inner cylinder, the sealing material and the valve box, and the thermal stress is reduced.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5, in the butterfly valve 21, an inner cylinder 24 made of a heat-resistant material is concentrically arranged inside a valve box 23 having connecting flanges 22 on both outer circumferences. A heat insulating material layer 25 is disposed between them, and a disc-shaped valve element 27 that rotates around the axis of the valve rod 26 to open and close the flow path is provided in the inner cylinder 24.

The valve box 23 has a valve box flange 28 protruding in the radial direction on the inner peripheral surface, and the inner cylinder 24 has an inner tube flange 29 protruding in the radial direction on the outer peripheral surface. Flange 28,
The inner cylinder flange 29 also has curved portions 28 a and 29 a along the outer circumference of the valve rod 26. These valve box flanges 2
8. The inner cylinder flange 29 is positioned to face each other via the axis of the valve rod 26 and is overlapped with each other. A gasket 30 also serving as a sliding material is interposed between the overlapped surfaces in the radial direction. In the elongated hole 31, the bolt 3 whose head covers the elongated hole 31
Bound by two. Thereby, the inner cylinder 24 is supported by the valve box 23.

The inner cylinder flange 29 is formed in a stepwise cross section, and has a step portion 29b facing the valve box flange 28 with an appropriate interval. Then, the flange seal seat portion 28, which faces the step portion 29b of the inner cylinder flange and the valve box flange 28 in the radial direction, respectively, is opposed to each other.
b, 29c are formed, and the flange seal seats 28b, 2
A sealing material 33, which is supported by 9c and has expandability in the radial direction, is arranged over the entire circumference of the inner cylinder 24. The flange seal seat portions 28b and 29c have curved surfaces whose opposing surfaces are parallel to the outer peripheral surface of the inner cylinder (and the inner peripheral surface of the valve box).

The sealing material 33 is formed of a thin plate material and has a shape as shown in FIG. That is, two frusto-conical cylinders 34, 35 having different diameters are concentrically arranged in opposite directions, and the bottom end edge 34a of the inner frusto-conical cylinder 34 and the outer frusto-conical cylinder are disposed. The head end edge 35a of 35 is welded to each other, and cutout portions 34b and 35b along the outer peripheral surface of the valve rod are provided at a portion facing the valve rod. Then, it is welded to the flange seal seat portion 28b at the bottom end edge 35c of the outer frustoconical cylinder body 35, and is welded to the flange seal seat portion 29c at the head end edge 34c of the inner frustoconical cylinder body 34. There is.

A valve seat projection 36 is formed on the inner circumference of the inner cylinder 24, the outer periphery of which is in close contact with the valve body 27 when the valve body 27 is placed in the fully closed position. A holding plate 37 that prevents the heat insulating material layer 25 from falling out is provided on the inner circumference of both ends. A cylindrical refrigerant passage (not shown) is formed in the shaft core of the valve rod 26.

The operation of the above configuration will be described. When a high-temperature fluid flows in the inner cylinder 24, the inner cylinder 24 becomes hot, but the valve box 23 does not have such a high temperature because the heat insulating material layer 25 is interposed. Therefore, a commercially available suitable material is used. The required strength can be ensured, and since the inner cylinder 24 becomes high in temperature, a large portion of the fluid pressure is supported by the valve box 23, so a large strength is not required. Therefore, commercially available heat-resistant steel is used. However, it can withstand the high temperature sufficiently. Further, since the inner cylinder 24 is present on the inner circumference of the heat insulating material layer 25, the heat insulating material does not flow downstream due to the flow of the fluid.

On the other hand, since the heat insulating material layer 25 is interposed between the inner cylinder 24 and the valve box 23, a large temperature difference occurs and a thermal expansion difference occurs. The difference in thermal expansion between the inner cylinder 24 and the valve housing 23 in the radial direction is due to the difference between the valve housing flange 28 and the inner cylinder flange 29.
Are overlapped with each other and fastened by the bolts 32 in the long holes 31, the valve box flange 28 and the inner cylinder flange 29 are absorbed by sliding on each other at their overlapping surfaces. At that time, since the gasket 30 interposed between the overlapping surfaces acts as a sliding member, the difference in thermal expansion is more smoothly absorbed, and excessive stress is locally generated or the inner cylinder 24 is not deformed. To be prevented.

The difference in thermal expansion between the inner cylinder 24 and the valve box 23 in the axial direction is appropriately absorbed at the connecting portion with the pipe connected to the butterfly valve 21. At this time, since the valve box flange 28 and the inner cylinder flange 29 are located opposite to each other with the axis of the valve rod 26 in between, the thermal symmetry does not collapse, and the valve when the flow path is fully closed is maintained. The close contact between the body 27 and the valve seat protrusion 36 is ensured.

Further, the flange seal seat portion 29c of the inner cylinder flange 29 and the flange seal seat portion 2 of the valve box flange 28 are provided.
Since the sealing material 33 is disposed so as to be supported by 8b,
Even when the internal fluid flows into the heat insulating material layer 25, it is blocked by the sealing material 23 and does not flow down beyond the butterfly valve 21.

Although the sealing material 33 also thermally expands, since the inner truncated cone cylindrical body 34 and the outer truncated cone cylindrical body 35 are welded to each other, they have expandability and contractibility in the radial direction. Moreover, since it is formed of a thin plate material, the temperature gradient between the inner cylinder, the seal material, and the valve box becomes gentle, so that the difference in thermal expansion is absorbed under relatively low stress.

FIG. 6 shows a main part of a butterfly valve of another embodiment. Here, the sealing material 33 has four frustoconical cylinders 38, 39, 40, 41 having different diameters arranged concentrically and in opposite directions, and the bottoms of the inner frustoconical cylinders, respectively. It is formed by welding the end edge and the head end edge of the outer frustoconical cylinder, and is provided with a notch (not shown) along the outer peripheral surface of the valve rod at a portion facing the valve rod. There is.

Then, the bottom end edge of the outermost frustoconical cylinder body 41 is welded to the valve box flange 28, and the step portion 29b of the inner cylinder flange 29 is joined to the head end edge of the innermost frustoconical cylinder body 38. It is welded to.

Furthermore, a butterfly valve as shown in FIG. 7 can also be implemented. The sealing material 33 is formed by concentrically disposing cylindrical bodies 42 and 43 having a cross section as shown in the drawing and welding them together. 44 is a fastener.

[0033]

As described above, according to the butterfly valve of the present invention, the difference in thermal expansion between the valve box and the inner cylinder is achieved by overlapping the flanges projecting from the valve box and the inner cylinder and connecting them by bolts. Can be easily absorbed by the slip between the flanges, and large thermal stress can be prevented from occurring in the inner cylinder and the valve box. Further, since the flanges are opposed to each other via the axis of the valve rod, the thermal symmetry does not deteriorate, and the close contact between the valve body and the valve seat protrusion can be ensured when the flow path is fully closed.

By interposing a sliding material between the overlapping surfaces of the flanges, the sliding between the flanges can be further improved and the difference in thermal expansion can be more easily absorbed. By arranging the sealing material that seals between the valve box and the inner cylinder over the entire circumference of the inner cylinder, the internal fluid that has flowed into the heat insulating material layer can be blocked by the sealing material. It can be prevented from flowing down.

By forming the flange seal seat portion, the seal material can be easily installed, and since the seal material has expandability in the radial direction, the stress at the time of thermal expansion can be reduced.

The bottom edge of the inner frusto-conical cylinder and the head edge of the outer frusto-conical cylinder are welded to each other to form a sealing material, which is a relatively compact sealing material. It can absorb its thermal expansion under low stress and block internal fluids.

By forming the sealing material from a thin plate material, the temperature gradient between the inner cylinder, the sealing material and the valve box can be made gentle, and the thermal stress in the sealing material can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the overall configuration of a butterfly valve according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing the configuration of the same butterfly valve excluding the valve body from another direction.

FIG. 3 is a perspective view of an inner cylinder forming the butterfly valve.

FIG. 4 is a perspective view of a sealing material that constitutes the butterfly valve.

FIG. 5 is an explanatory view showing the same butterfly valve taken along the line AA in FIG. 2.

FIG. 6 is a vertical cross-sectional view of a main part of a butterfly valve according to another embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view of a main part of a butterfly valve according to another embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view showing the overall configuration of a conventional butterfly valve.

[Explanation of symbols] 21 Butterfly valve 23 Valve box 24 Inner tube 25 Insulation material layer 26 Valve rod 27 Valve body 28 Valve box flange 29 Inner tube flange 28a, 29a Curved section 28b, 29c Flange seal seat section 30 Gasket (sliding material) 31 Slot 32 Bolt 33 Seal material 34,35 Frustroconical conical body 34b, 35b Notch

Claims (6)

[Claims] 1. A valve box and an inner cylinder are concentrically arranged, a heat insulating material layer is arranged between the valve box and the inner cylinder, and the inner cylinder is rotated about an axis of a valve rod. In a butterfly valve provided with a disc-shaped valve body that opens and closes a flow path, the valve box has a valve box flange projecting in a radial direction on an inner peripheral surface, and the inner cylinder projects in a radial direction. Has an inner cylinder flange on the outer peripheral surface, the valve box flange and the inner cylinder flange have a curved portion along the outer periphery of the valve rod, and are located opposite to each other via the axial center of the valve rod, A butterfly valve, characterized in that they are polymerized together and are bolted together in a long hole along the radial direction. 2. The butterfly valve according to claim 1, wherein a sliding material is interposed between the overlapping surfaces of the valve box flange and the inner cylinder flange. 3. The butterfly valve according to claim 1, wherein a sealing material for sealing between the valve box and the inner cylinder is provided over the entire circumference of the inner cylinder. 4. A seal material having radial expansion and contraction properties is formed on each of the valve box flange and the inner cylinder flange by forming flange seal seat portions facing each other in the radial direction and supporting them on both flange seal seat portions. The butterfly valve according to claim 3, wherein the butterfly valve is provided. 5. The sealing material comprises a plurality of frustoconical cylinders having different diameters arranged concentrically and in opposite directions, and the bottom end edge of the inner frustoconical cylinder and the outer frustoconical cylinder. It is welded to the head edge of the body and has a notch along the outer peripheral surface of the valve stem at the part facing the valve stem. The outermost truncated cone end and the innermost truncated cone. The butterfly valve according to claim 4, wherein the conical tubular body is welded to the valve box flange and the inner tubular flange at an end portion thereof. 6. The butterfly valve according to claim 3, wherein the sealing material is formed of a thin plate material.