JP2002181204A - Butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relieve operation torque produced during closing of a valve and facilitate manufacture without needing high working accuracy. SOLUTION: In a butterfly valve 20 formed that a seat ring 22 made of rubber is removably mounted on a valve body 21, a seat ring consist of a cylinder part 22a to cover the inner surface of the valve body and a flange part 22b to cover the end face of the valve body, a middle high part 22c for a valve seat is formed on the inner surface of the cylinder part 22a and a peripheral protrusion 22d is formed on the outer surface thereof, the protrusion 22d is fitted in a recess groove 21a in the inner surface of the valve body 21, and the outer periphery of a disc-formed valve plate 23 is brought into pressure contact with the middle high part 22c to close the valve. The button surface of the recess groove 21a of the inner surface of the valve body and the top part of the protrusion 22d of the seat ring 22 form cylinder surfaces S with diameters equal to each other. Its central line M forms a straight line crossing orthogonally with a valve stem 24 and inclining at an angle θ in a valve closing direction with a central line N of the valve body 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve interposed in a pipe for controlling a fluid such as water and air flowing through the pipe.

[0002]

2. Description of the Related Art As a butterfly valve which constitutes a pipe for fluid transport and is interposed between two pipes adjacent to each other in the front and rear, 2
A cylindrical valve body connected between the end flanges of the pipe, a seat ring made of a rubber-like elastic body formed in a cylindrical shape covering the inner surface of the valve body, and a diametrical direction of the valve body. A disc-shaped valve body that rotates around the valve shaft, and when the valve body is rotated to be orthogonal to the center axis of the valve body, the outer periphery of the valve body is pressed against the inner surface of the seat ring. 2. Description of the Related Art A center type butterfly valve in which a pipe is closed is known.

FIG. 3 shows an example of a center type butterfly valve 10, in which 11 is a cylindrical valve body, 12 is a seat ring, 1
3 is a valve shaft and 14 is a valve body. The seat ring 12 includes a cylindrical portion 12a covering the inner surface of the valve body 11 and the cylindrical portion 12a.
and a flange 12b projecting radially outward from both ends of the valve body 11 to cover the end surface of the valve body 11, and is formed detachably with respect to the valve body 11; The portion 12c is formed continuously in the circumferential direction, so that the pressure difference at the start of opening of the valve body 14 can be reduced without lowering the sealing pressure at the time of fully closing as compared with the case without the middle and high portions 12c. It has become.

The above-mentioned butterfly valve 10 rotates in a closing direction (the direction of the arrow P in FIG. 3) from a state where the valve body 14 is opened, and the valve body 14 comes into pressure contact with the middle and high section 12c of the seat ring 12 so as to be pressed. Is compressed obliquely forward with respect to the radial direction of the valve body 11, the oblique force F is generated at a contact portion between the inner surface of the valve body 11 and the outer surface of the cylindrical portion 12 a of the seat ring 12. When this force F is divided into a horizontal component A along the inner surface of the valve body 11 and a vertical component B in the radial direction, the seat ring 12 only fits on the inner surface of the valve body 11. The horizontal component A causes a displacement between the outer surface of the cylindrical portion 12a of the seat ring 12 and the inner surface of the valve body 11, and the middle and high portions 12c escape from the valve body 11 to deteriorate the sealing performance. Was.

[0005] To prevent this reduction in sealing performance, FIG.
As shown in FIG.
a is formed in the circumferential direction, while a ridge 12 d having a rectangular cross section is provided on the outer surface of the cylindrical portion 12 a of the seat ring 12 in the circumferential direction,
A configuration in which a ridge 12d is fitted into a concave groove 11a is known. In this case, the cylindrical portion 12 of the seat ring 12
a, the sealability is more stable than that of the butterfly valve of FIG. 1, but the cylindrical portion 12a and the valve body 1
Since the horizontal component of the force acting on the contact portion of the inner surface 1 is the same as that of the butterfly valve in FIG. 3, the operating torque of the valve body 14 was not reduced. In addition, the above-mentioned concave groove 11a and ridge 12d
Was omitted and an attempt was made to machine the inner surface of the valve body 11 into a rough surface instead. However, in this case also, the effect of reducing the operating torque was not obtained.

In Japanese Patent Publication No. 55-18297, the seat ring 12 made of the rubber-like elastic body is omitted, and instead, as shown in FIG. The seat ring 11b for a valve seat is integrally protruded in the form of a ridge, and its tip 11c is formed in the shape of a cylindrical surface 15 inclined with respect to the center line of the valve body 11 (however, the cylindrical surface 15 with respect to the valve body 11). The inclination angle is set to 5 to 15 degrees in the valve closing direction around the valve shaft 13).
A metal valve body 14 in which an outer periphery 14a is formed in a cylindrical surface closely contacting the cylindrical surface 15 is disclosed.

In this case, the intersection angle between the center line of the cylindrical surface 15 and the center line of the valve body 11 is set to the above-mentioned size, so that the valve seat seat ring 11b and the valve body 14
And the operating torque of the valve body 14 can be greatly reduced by suppressing the friction generated between the valve body 14 and the front end 11c of the valve seat ring 11b and the outer peripheral surface 14a of the valve body 14. Required, and its processing and maintenance of accuracy were extremely difficult.

[0008]

The present invention relates to FIG.
Butterfly valve of the type, that is, a seat ring made of a rubber-like elastic body is detachably attached to the cylindrical valve body, and the seat ring projects from both ends of the cylindrical portion covering the inner surface of the cylindrical valve body and its both ends. A flange portion covering the end surface of the valve body, a middle and high portion for a valve seat is formed on an inner surface of the cylindrical portion, and a ridge is formed on an outer surface in a circumferential direction, and the ridge is formed on an inner surface of the valve body. In the butterfly valve fitted in the recessed groove, the operation torque generated when the valve is closed is further reduced, and high-precision machining accuracy is not required, thereby facilitating manufacture.

[0009]

In a butterfly valve according to the present invention, a seat ring made of a rubber-like elastic body is detachably mounted on a cylindrical valve body, and the seat ring covers an inner surface of the valve body. It comprises a cylindrical portion and a flange portion extending from both ends thereof and covering the end surface of the valve body. A mid-high portion for a valve seat is formed on the inner surface of the cylindrical portion, and a circumferential ridge is formed on the outer surface. The valve fits into a circumferential concave groove formed on the inner surface of the valve body, and the outer periphery of a disc-shaped valve plate fixed to the diametric valve shaft of the valve body comes into pressure contact with the middle and high portions to open the valve. In the butterfly valve, the bottom of the concave groove on the inner surface of the valve body and the top of the ridge on the outer surface of the cylindrical portion of the seat ring are formed on a cylindrical surface having the same diameter as each other, and the center line thereof is defined as the valve shaft. At right angles to the valve body center line And characterized in that it.

When the above-mentioned butterfly valve is interposed and fixed between the end flanges of two pipes adjacent to each other in the front and rear in the pipeline, when the disc-shaped valve body of the butterfly valve is rotated around the valve shaft, Similar to a butterfly valve having a seat ring made of a conventional rubber-like elastic body and having a middle and a high portion on the inner surface of the cylindrical portion and a ridge on the outer surface, when the valve body is oriented parallel to the pipeline, When the path is fully opened and the valve element is orthogonal to the pipe, the entire outer periphery of the valve element comes into contact with the middle and high parts of the seat ring and becomes fully closed. , The operating torque of the valve body is reduced, and the sealing pressure when fully closed is not reduced.

However, in the present invention, the top of the protrusion on the outer surface of the cylindrical portion and the bottom surface of the concave groove of the valve body corresponding to the top are formed in cylindrical surfaces having the same diameter, and the center line thereof is orthogonal to the valve axis. Since the valve body is inclined in the valve closing direction with respect to the center line of the valve body, when the valve body contacts the middle and high parts of the seat ring and closes the middle and high parts when closing the valve, the top of the ridge and the concave groove are formed. A conventional butterfly, in which the horizontal component of the force acting on the contact surface of the bottom surface (the component force acting in the generatrix direction of the cylindrical surface) forms the top of the ridge and the bottom surface of the concave groove on a cylindrical surface parallel to the inner surface of the valve body. It becomes smaller than the valve, and the vertical component increases accordingly.

Since the horizontal component force is reduced as described above, the displacement of the seat ring when closing the valve is reduced as compared with the conventional case, and the sealing performance is further stabilized. Also, since the vertical component is increased, the sealing performance is improved. Therefore, even if the force acting on the contact surface between the top of the ridge and the bottom surface of the groove is smaller than before, the same vertical component as before And torque can be reduced. In addition, since the contact surface between the top of the ridge and the bottom of the concave groove is inclined as described above, it is possible to make the compression rate of the seat ring when the valve body and the seat ring are pressed against each other proportional to the valve opening. Therefore, as the valve is closed, the sealing force increases, and when the valve is opened, a force acts in a direction to release the compression, and the torque when the valve is opened is reduced.

The ridges and grooves serve as stoppers for preventing the cylindrical portion of the seat ring from shifting.
The seal surface is independent of the seal surface of the butterfly valve, the seal surface is formed at the contact portion between the middle and high portions of the seat ring and the outer periphery of the valve body, and the seat ring provided with the ridge is made of a rubber-like elastic body. Therefore, high precision is not required for processing the contact surfaces of the ridges and grooves, and the manufacturing is easy.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 20 denotes a butterfly valve, 21 denotes a valve body, 22 denotes a seat ring, 23 denotes a disc-shaped valve body, and 24 denotes a valve shaft. The valve body 21 is formed in a cylindrical shape from metal or hard synthetic resin.
The seat ring 22 is made of a rubber-like elastic body such as vulcanized rubber, and has a cylindrical portion 22a fitted to the inner surface of the valve body 21;
A flange portion 22b that extends radially outward from both ends of the cylindrical portion 22a and covers the end surface of the valve body 21 is formed. And this flange part 22b is the valve body 2
1 is removably fitted into an end face stepped portion 21b recessed from the end face.

On the inner surface of the cylindrical portion 22a of the seat ring 22, a mid-high portion 22 forming a valve seat is provided at the center in the width direction.
c is continuously provided in the circumferential direction, and a ridge 22d having a trapezoidal cross section is continuously provided in the center in the width direction of the outer surface in the circumferential direction. The ridge 22d is formed on the inner surface of the valve body 21. The seat ring 22 is prevented from being displaced by being fitted in the groove 21a having a trapezoidal cross section. Here, the top of the protruding ridge 22d and the bottom surface of the concave groove 21a are formed in cylindrical surfaces S having the same diameter. However, the center line M of the cylindrical surface S is
Is rotated clockwise from the valve open state to reach the fully closed state shown in FIG.
1 is a straight line inclined by an angle θ in the valve closing direction with respect to the center line N.

The cross-sectional shape of the concave groove 21a is a straight line parallel to the center line N of the valve body 21 and along the inner surface of the valve body 21 and a bottom surface of the concave groove 21a parallel to the center line M of the cylindrical surface S. Are formed as a pair of sides, and one end and the other end of the pair of sides are respectively connected to form a trapezoid having two straight lines perpendicular to the center line N of the valve body 21 as a pair of sides. And
The cross-sectional shape of the ridge 22d is substantially the same as the cross-sectional shape of the concave groove 21a.

In the above structure, as shown in FIG.
When the valve element 23 rotates clockwise (in the direction of arrow P) from the valve open state to close the valve, if the valve element 23 comes into contact with the middle high portion 22 c of the seat ring 22, the bottom surface of the concave groove 21 a on the inner surface of the valve body 21. A force F is generated at a contact portion between the outer surface of the seat ring 22 and the top of the ridge 22d. This force F is a component force in the generatrix direction (horizontal component force) A of the cylindrical surface S constituting the bottom surface and the top portion.
1 is inclined with respect to the valve body 21 by the angle θ, so that the force F in FIG. 2 is different from the force F in FIG. If equal, horizontal component A
2 is smaller in FIG. 2 than in FIG. 3 according to the magnitude of the inclination angle θ, and the vertical component B is correspondingly larger.

The above-mentioned inclination angle θ varies depending on the diameter of the valve, but is generally preferably in the range of 5 to 15 degrees in order to reduce the horizontal component of the force F by 10% or more. In addition, the concave groove 21
The width (the vertical dimension in FIG. 1) of the a and the ridge 22d is in the range of 5 to 20 mm, and is preferably about １ ／ of the width (the vertical dimension) of the cylindrical portion 22a. The depth of the groove 21a and the height of the ridge 22d are 3 to 10 at the end (the upper end in FIG. 1) in the valve closing direction.
mm is preferable, and if it is less than 3 mm, the effect of preventing displacement is not obtained. Conversely, if it exceeds 10 mm, the middle and high portions 22c of the seat ring 22 become thick, and it becomes difficult to obtain a desired effect due to the inclination.

[0019]

As described above, in the butterfly valve according to the present invention, the bottom surface of the concave groove on the inner surface of the valve body and the protrusion on the outer surface of the cylindrical portion of the seat ring are formed into cylindrical surfaces having the same diameter.
Since the center line is a straight line that is orthogonal to the valve axis and inclined in the valve closing direction with respect to the center line of the valve body, the displacement of the seat ring when closing the valve is smaller than before. In addition, the sealing performance is further improved, the sealing performance is improved, the operating torque can be reduced accordingly, and high precision is not required for machining, and the production is easy.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a cross-sectional view illustrating an operation.

FIG. 3 is a sectional view of a first conventional example.

FIG. 4 is a sectional view of a second conventional example.

FIG. 5 is a sectional view of a third conventional example.

[Explanation of symbols]

 20: Butterfly valve 21: Valve body 21a: Concave groove 21b: End face step 22: Seat ring 22a: Cylindrical part 22b: Flange part 22c: Middle high part 22d: Ridge 23: Valve body 24: Valve shaft S: Cylindrical surface, M: center line, N: center line, θ: angle

Claims (1)

[Claims] A seat ring made of a rubber-like elastic body is detachably mounted on a cylindrical valve body, and the seat ring projects from both ends of the cylindrical portion covering the inner surface of the valve body and an end face of the valve body. And a flange portion covering the inner surface of the cylindrical portion, a middle-high portion for the valve seat is formed on the inner surface of the cylindrical portion, and a circumferential ridge is formed on the outer surface, and the circumferential ridge is formed on the inner surface of the valve body. A butterfly valve fitted in a concave groove, wherein an outer periphery of a disc-shaped valve plate fixed to a valve shaft in a diameter direction of the valve body is pressed against the middle and high portion to close the valve. The bottom surface of the concave groove on the inner surface of the body and the top of the ridge on the outer surface of the cylindrical portion of the seat ring are formed in cylindrical surfaces having the same diameter, and the center line is orthogonal to the valve axis and the valve is closed with respect to the center line of the valve body. A butterfly valve characterized by being inclined in a direction.