JPH0617944A - Butterfly valve for high temperature - Google Patents

Abstract

PURPOSE:To surely prevent leaks by bringing a valve element side seat surface into good contact with a valve box side seat surface regardless of the intensity of fluid pressure applied to a valve element held in its closed position while eliminating the thermal influence of high-temperature fluids and to enable the seat surfaces to be readily set in a good contact state after assembly even if the accuracy of the clearance between a valve shaft and a bearing is bad. CONSTITUTION:A projecting portion 8 is formed on the outer periphery of the center boss portion 3a of a valve element 3, the center boss portion 3a being secured to a valve shaft 4 at a position biased from seat surfaces 6, 7 to the direction of flow of fluids; a movable pressar member 9, by which the valve element 3 being rotated to its closed position is pressed via the projecting portion 8 in the direction in which it makes contact with each seat surface, is held in a state in which the amount by which it presses a support 10 located on the side of a valve box 2 can be adjusted.

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 used for opening and closing a high temperature fluid passage.

[0002]

2. Description of the Related Art Conventionally, as this type of butterfly valve, those shown in FIGS. 5 and 6 have been known. This butterfly valve includes a valve box 52 having an annular seat surface 51 and a bearing 5
The valve shaft 56 is supported via the valve shaft 3 and the valve body 56 having the seat surface 55 corresponding to the valve box side seat surface 51 on the outer periphery is disposed at a position eccentric to the seat surfaces 51 and 55 in the fluid flow direction. Through the central boss portion 56a of the valve body 56, the valve shaft 54
The valve body 56 is fixed to the valve body 56, and the valve body 56 is pivotally operated via the valve shaft 54 so that the valve body side seat surface 55 is closely attached to the valve box side seat surface 51 so as to be separable.

By the way, when the valve body 56 is made of rubber, the adhesion between the seat surfaces 51 and 55 is improved, but
When used in a high temperature fluid flow path, the rubber is liable to be thermally adversely affected, and a predetermined adhesion cannot be obtained. Therefore, for high temperatures, the valve body 56 is made of metal. In this case, the bearing 53 has a certain clearance G with respect to the valve shaft 54 in consideration of thermal expansion of the valve shaft 54 and the like. Supported to have.

[0004]

However, according to the above-mentioned conventional structure, since the valve body 56 is made of metal, the valve body side seat surface 55 when the valve body 56 is rotated to the closed position.
Adhesion to the valve box side seat surface 51 is worse than in the case of a rubber valve body.

In particular, when a large fluid pressure is applied to the valve body 56 from the direction indicated by the arrow A at the closed position, the clearance G causes the valve body 56 to be displaced downstream by the clearance. , A gap is created between the seat surfaces 51 and 55, which causes fluid leakage.

Further, even if the fluid pressure is from the opposite direction (the direction of arrow B), if the pressure is small, the valve element 56
There remains anxiety about the adhesion between the two seat surfaces 51, 55 at the closed position.

The present invention has been made to solve the above-mentioned conventional problems, and the close contact of the seat surface does not depend on the magnitude of the fluid pressure urged by the valve body at the closed position. It is an object of the present invention to provide a high temperature butterfly valve which can improve the performance and can easily adjust the positioning of the valve body after assembly.

[0008]

In order to achieve the above object, the present invention supports a valve shaft with a certain clearance in a bearing fixed to a valve box having an annular seat surface, and the valve box side seat on the outer periphery. The valve body having a seat surface corresponding to the surface is fixed to the valve shaft via the central boss portion of the valve body at a position eccentric to both seat surfaces in the fluid flow direction, and the valve body is rotated via the valve shaft. In a butterfly valve for high temperature in which the valve body side seat surface is brought into close contact with and separated from the valve box side seat surface by a dynamic operation, a convex portion is formed on the outer periphery of the central boss portion of the valve body, and the valve body A movable pressing member that presses the valve body through the convex portion in a direction in which both seat surfaces come into close contact with each other when the sheet is rotated to the closed position, by pressing the movable pressing member on the support body fixed to the valve box. It is held in an adjustable state.

[0009]

With the above construction, when the valve element is rotated through the valve shaft and displaced along the flow direction of the fluid, the flow path is set to the open state. Further, when the valve body is rotationally displaced so as to be orthogonal to the flow direction, the valve body side seat surface comes into close contact with the valve box side seat surface, and a closed state is established.

At this time, due to the clearance between the valve shaft and the bearing, the thermal expansion of the valve shaft and the like due to the high temperature fluid is absorbed and the opening / closing operation becomes smooth. In particular, even if a large pressure of the fluid is applied to the valve body in the closed position to cause a gap in the seat surface, the valve body is pressed against the pressure by the movable pressing member via the convex portion, so that the valve is pressed. The body side seat surface strongly adheres to the valve box side seat surface. Further, even when the fluid pressure from the opposite direction is small, the adhesion between the two sheet surfaces is maintained, and there is no risk of leakage.

Further, even if there is a variation in the clearance amount or the like, the closed position of the valve body can be easily and properly set by variably adjusting the pressing amount by the movable pressing member after assembly.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing an entire valve device to which a high temperature butterfly valve according to an embodiment of the present invention is applied.

In FIG. 1, reference numeral 1 denotes a high temperature butterfly valve, which includes a valve box 2, a valve body 3, a valve shaft 4 and a bearing 5. 6 is a member that supports the upper end side of the valve shaft 4, and 7 is an opening / closing operation mechanism portion that opens and closes the valve body 3 via the valve shaft 4.

The structure of the main part of the high temperature butterfly valve 1 is shown in FIGS. 2 and 3, an annular seat surface 6 is formed on the valve box 2, and the valve box 2
On the other hand, the valve shaft 4 is supported via a bearing 5. The bearing 5 is supported by the valve shaft 4 with a certain clearance G.

On the other hand, the valve body 3 is formed with a central boss portion 3a. The valve body 3 has the central boss portion 3a fixed to the valve shaft 4 such that the center of rotation is located at a position eccentric to the seat surfaces 6 and 7 in the fluid flow direction.

Reference numeral 8 is a convex portion formed on the outer periphery of the central boss portion 3a of the valve body 3, and correspondingly, when the valve body 3 is rotated to the closed position in the valve box 2. A movable retainer member 9 is arranged to press the valve body 3 through the convex portion 8 in a direction in which the valve body side seat surface 7 closely contacts the valve box side seat surface 6. The movable pressing member 9 uses, for example, a bolt, and is configured to be screwed into the screw hole 10a of the support body 10 fixed to the valve box 2 so that the pressing amount can be adjusted. Reference numeral 11 is a nut screwed to the bolt 9.

With the above structure, the flow path is opened by rotating the valve body 3 through the valve shaft 4 to a position along the flow direction of the fluid. Further, by rotating the valve body 3 through the valve shaft 4 to a position (FIG. 1) orthogonal to the flow direction of the fluid, the valve body side seat surface 7 becomes the valve box side seat surface 6
And the flow path is closed. In this case, due to the clearance G existing between the valve shaft 4 and the bearing 5,
The thermal expansion of the above is absorbed and the opening / closing operation is smoothly performed without any trouble.

When the valve body 3 is rotated to the closed position, the convex portion 8 formed on the central boss portion 3a causes the valve box 2 to move.
It is pressed by the movable pressing member 9 on the side. That is, when the valve body 3 is closed and a large fluid pressure is applied from the direction of arrow A,
While the valve body 3 is about to be displaced toward the downstream side by the clearance G, the bolt 9 pushes the valve body 3 back upstream via the convex portion 8. Therefore, the valve body side seat surface 7 in the closed state strongly adheres to the valve box side seat surface 6, and the occurrence of leakage is reliably prevented.

When the pressure of the fluid from the direction of the arrow B is received in the closed state of the valve body 3, the bolt 9 is forcibly forced through the convex portion 8 even if this pressure is small. Since 3 is displaced, strong adhesion between the valve body side seat surface 7 and the valve box side seat surface 6 can be obtained, and the risk of leakage can be eliminated.

The amount of pressing of the valve element 3 is adjusted by screwing the bolt 9 to adjust the amount of advance / retreat. That is, even if there is a variation in the clearance G between the valve shaft 4 and the bearing 5, the two seat surfaces 6 and 7 can be easily set to a proper contact state by adjusting the pressing amount by the bolt 9 after assembly. can do.

FIG. 3 shows a modified structure of the essential part of the present invention, in which the bolt 9 is axially movably held in the through hole 12 of the support 10, while the bolt 9 is constantly provided with a spring force in the pressing direction. A spring member 13 for urging is attached. In this case, the valve body 3 is rotated to the closed position so that the convex portion 8 becomes the bolt 9
Since the impact at the time of hitting the spring is absorbed by the spring member 13,
It will help protect the parts.

[0022]

As described above, according to the present invention, thermal expansion can be absorbed by the clearance between the valve shaft and the bearing, and the convex portion of the valve body which is rotationally displaced to the closed position is supported on the valve box side. Since the movable pressing member held by the body is used for pressing, the valve body side seat surface can be brought into good contact with the valve box side seat surface without being affected by the pressure applied to the valve body. Regardless of the magnitude of the fluid pressure, it is possible to reliably prevent the occurrence of leakage.

Moreover, since the pressing amount can be adjusted by the movable pressing member, the valve body after assembly can be easily positioned even if there are variations in clearance, etc. Can be adjusted and set.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a valve device to which a butterfly valve for high temperature according to an embodiment of the present invention is applied.

FIG. 2 is a plan sectional view showing a configuration of a main part of the high temperature butterfly valve.

3 is a cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a plan sectional view showing a modified structure of a main part of the high temperature butterfly valve according to the present invention.

FIG. 5 is a plan sectional view showing a configuration of a main part of a conventional high temperature butterfly valve.

6 is a cross-sectional view taken along line VI-VI of FIG.

[Explanation of symbols]

 2 Valve box 3 Valve body 3a Central boss section 4 Valve shaft 5 Bearing 6 Valve box side seat surface 7 Valve body side seat surface 8 Convex section 9 Movable pressing member 10 Support G clearance

Claims (1)

[Claims] 1. A valve element having a seat surface corresponding to the seat surface on the valve box side on the outer periphery of which is supported by a bearing fixed to a valve box having an annular seat surface with a certain clearance. On the other hand, by fixing the valve body to the valve shaft via the central boss portion of the valve body at a position eccentric in the fluid flow direction, and rotating the valve body via the valve shaft, the valve body side seat surface is moved to the valve box side seat. In a butterfly valve for high temperature, which is designed to be in close contact with and separated from the surface, a convex portion is formed on the outer periphery of the central boss portion of the valve body, and both seat surfaces when the valve body is rotated to the closed position. For a high temperature, characterized in that a movable pressing member that presses the valve body through the convex portion in the direction in which the Butterfly valve.