JPH0617945A - 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 fluid pressure applied to a valve element held in its closed position, while eliminating the thermal influence of high-temperature fluids. 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 presser 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 provided in a valve box 2.

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. 4 and 5 have been known. This butterfly valve includes a valve box 42 having an annular seat surface 41 and a bearing 4
3, the valve shaft 44 is supported via the valve shaft 3, and the valve body 46 having the seat surface 45 corresponding to the valve box side seat surface 41 on the outer periphery is disposed at a position eccentric to the seat surfaces 41, 45 in the fluid flow direction. The valve shaft 43 is inserted through the central boss portion 46a of the valve body 46.
The valve body-side seat surface 45 is brought into close contact with and separated from the valve box-side seat surface 41 by rotating the valve body 46 via the valve shaft 44.

By the way, when the valve body 46 is made of rubber, the adhesion between the seat surfaces 41 and 45 is improved, but
When used in a high temperature fluid flow path, the rubber is liable to be adversely affected by heat and the desired adhesion cannot be obtained. Therefore, when used as a high temperature fluid, the valve body 46 is made of metal. In the butterfly valve using the metal valve element 46, the bearing 43 is supported so as to have a constant clearance G with respect to the valve shaft 44 in consideration of thermal expansion of the valve shaft 44 and the like.

[0004]

However, according to the above-mentioned conventional structure, since the valve body 46 is made of metal, the valve body side seat surface 45 when the valve body 46 is rotated to the closed position.
The adhesion to the valve box side seat surface 41 is worse than that of the rubber valve body.

In particular, when a large fluid pressure is applied to the valve body 46 in the closed position from the direction indicated by the arrow A, the clearance G causes the valve body 46 to be displaced downstream by the clearance, and A gap is created between the seat surfaces 41 and 45, which causes 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 46
There remains anxiety about the close contact between the seat surfaces 41 and 45 at the closed position.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to improve the adhesion of the seat surface without being influenced by the fluid pressure applied to the valve body in the closed position. An object of the present invention is to provide a high temperature butterfly valve that can be improved.

[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 When the valve is rotated to the closed position, the valve box is provided with a 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.

[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 fluid is applied to the valve body in the closed position to cause a gap on the seat surface, the valve body is pressed against the pressure by the pressing member through the convex portion, 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.

[0011]

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. Further, the valve body 3 fixes the central boss portion 3a to the valve shaft 4 so that the rotation center exists at a position eccentric to the seat surfaces 6 and 7 in the fluid flow direction.

Reference numeral 8 denotes 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 pressing member 9 is provided to press the valve body 3 through the convex portion 8 in a direction in which the valve body side seat surface 7 is in close contact with the valve box side seat surface 6.

With the above structure, when the valve body 3 is rotated through the valve shaft 4 to a position along the flow direction of the fluid, the flow path is opened. Further, when the valve body 3 is rotated through the valve shaft 4 to a position (FIG. 1) orthogonal to the fluid flow direction,
The valve body side seat surface 7 comes into close contact with the valve box side seat surface 6 and the flow path is closed. In this case, the clearance G existing between the valve shaft 4 and the bearing 5 absorbs thermal expansion of the valve shaft 4 and the like, so that the opening / closing operation can be 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 holding member 9 on the side. That is, when the valve body 3 is closed, the valve body 3 tends to be displaced by the amount of the clearance G toward the downstream side due to the urging of a large fluid pressure from the direction of the arrow A, while the pressing member 9 is convex. Valve body 3 via part 8
Will be pushed back upstream. 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, even if the pressure is small, the holding member 9 forcibly presses the valve through the convex portion 8. Since the body 3 is displaced, again, the valve body side seat surface 7
A strong adhesion between the valve box side seat surface 6 can be obtained, and the risk of leakage can be eliminated.

[0019]

As described above, according to the present invention, the 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 provided on the valve box side. Since it is pressed by the pressing member, the valve body side seat surface can be brought into good close contact with the valve box side seat surface without being affected by the pressure applied to the valve body. Even in the body, regardless of the magnitude of the fluid pressure, the occurrence of leakage can be reliably prevented, and the closing performance can be improved.

[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.

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

FIG. 4 is a plan sectional view showing a configuration of a main part of a conventional high temperature butterfly valve.

5 is a cross-sectional view taken along the line VV 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 Holding member 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 come into close contact with and separate from a 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. A butterfly valve for high temperature, characterized in that a pressing member for pressing the valve body in the direction of close contact with the valve body is provided in the valve box.