JP2574864Y2 - Seal structure of butterfly valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for a butterfly valve.

[0002]

2. Description of the Related Art Conventional butterfly valves include, for example, FIG.
5 to FIG. 3 to 5, the valve box 1
The valve body 2 is disposed in the inside of the valve body 1 in a state of being inclined back and forth in the axial direction of the valve box 1, and the valve body 2 is provided with a valve stem 3 disposed in a direction perpendicular to the axis of the valve box 1. It rotates around the axis. Further, a valve box seat portion 4 is provided in an annular shape along the inner periphery of the valve box 1, and the valve body sheet portion 5 is formed around the entire outer periphery of the valve body 2 facing the valve box seat portion 4 by a ferrule. Has formed. In the fully closed state, the valve body seat portion 5 and the valve case seat portion 4 are brought into pressure contact with each other, so that the valve case 1 and the valve body 2 are pressed.
Between the seals.

[0003]

However, in the above-described conventional structure, the pressure contact surfaces of the valve body sheet portion 4 and the valve body sheet portion 5 which are made of a highly rigid metal body are pressed and sealed. High accuracy is required for the shape, and there is a problem that if a gap occurs between the sheet portions due to a processing error, the sealing property becomes insufficient. When a gap is formed between the valve box seat portion 4 and the valve body seat portion 5 on one side of the valve body 2, the valve box seat portion 4 and the valve body seat portion 5 are formed on the opposite side via the valve rod.
Have a problem that the opening / closing operation becomes difficult because the frictional force is increased due to excessively strong pressure contact.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a butterfly valve seal structure which can ensure high sealing performance without being affected by machining errors and can easily perform opening and closing operations. .

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention forms a valve box seat portion on an inner periphery of a valve box and forms an annular groove on an outer periphery of a valve body opposed to the valve box seat portion. Forming
A valve seat ring disposed in the groove is fitted at a proper distance between the bottom surface of the groove and the inner peripheral edge of the valve seat ring, and a suitable space in the circumferential direction is provided on the inner peripheral side of the valve seat ring. In this configuration, a plurality of slits are provided in the radial direction.

[0006]

With the above construction, in the fully closed state, the valve body seat ring presses against the valve box seat portion to seal between the valve box and the valve body. At this time, when the valve body seat ring is biased against one side of the valve body seat portion and pressed against one side due to axial misalignment between the valve box and the valve body, one side of the valve body seat ring generates a reaction force caused by the pressing. The valve seat seat ring retreats in the groove, and the other side of the valve body seat ring advances in the groove toward the opposing portion of the valve box seat, so that the valve body seat ring and the valve box seat are evenly distributed over the entire circumference. Crimp. Also, when the valve body seat ring is deformed into distortion due to the distortion of the valve box or the like, the slit absorbs the distortion and elastically deforms.

Therefore, the distortion of the valve box, the processing error in the valve box seat, the displacement of the axial center in the mounting structure of the valve body, and the like can be absorbed by the movement in the groove of the valve body seat ring and the elastic deformation. Uniform sealing properties can be secured over the entire circumference of the body seat ring.
Also, when opening and closing the valve body, the valve body seat ring and the valve box seat portion are pressed uniformly over the entire circumference, so that the opening and closing operation can be easily performed with a light operating force.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Since the main configuration of this embodiment is the same as that shown in FIGS. 3 to 5, the main part of the present invention is shown in FIGS.

1 and 2, a valve box seat portion 12 is formed in an annular shape on the inner surface of a valve box 11, and a valve body that rotates in a direction 13 around the axis of a valve rod is provided inside the valve box 11. 14 are provided. An annular holding plate 16 for holding a metal valve seat ring 15 is fixed to the outer peripheral portion of the valve body 14 with bolts 17, and the valve body 14 and the holding plate facing the valve box seat portion 12 are fixed. An annular groove 18 is formed on the outer periphery of the groove 16.

The valve seat ring 15 has a U-shaped cross section, an arc portion 15a abuts on the valve box seat portion 12, and an appropriate gap X is provided between the inner peripheral edge 15b and the bottom surface of the groove portion 18 so as to be formed in the groove portion 18. It is fitted. Further, a plurality of slits 19 are provided at appropriate intervals in the circumferential direction on the inner peripheral side of the valve seat ring 15.
Is cut in the radial direction. Further, between the valve body seat ring 15 and the valve body 14, between the valve body seat ring 15 and the holding plate 16, and between the valve body 14 and the holding plate 16, water is stopped by a rubber ring 20.

The operation of the above configuration will be described below.
In the fully closed state, the valve body seat ring 15 is pressed against the valve box seat portion 12 to seal between the valve box 11 and the valve body 14. At this time, the valve body seat ring 15 is displaced by the axial center misalignment between the valve box 11 and the valve body 14 so that the valve body seat portion 1 is not moved.
When one side of the valve body seat ring 15 is pressed against the one side of the valve body 2, one side of the valve body seat ring 15 receives the reaction force caused by the pressing and retreats so as to reduce the gap X in the groove 18. The other side advances in the groove portion 18 toward the opposing portion of the valve box seat portion 12, and the valve body seat ring 15 and the valve box seat portion 12 are pressed uniformly over the entire circumference. In addition, when the valve body seat ring 15 is deformed into distortion due to the distortion of the valve box 11 or the like, each slit 19 absorbs the distortion and elastically deforms.

Therefore, the distortion of the valve box 11, the processing error in the valve box seat 12, the axial displacement in the mounting structure of the valve body 14, and the like are absorbed by the movement and elastic deformation of the valve body seat ring 15 in the groove 18. It is possible,
A uniform sealing property can be ensured over the entire circumference of the valve body seat ring 15. Also, when opening and closing the valve body 14, the valve body seat ring 15 and the valve box seat portion 12 are pressed uniformly over the entire circumference, so that the opening and closing operation can be easily performed with a light operating force.

[0013]

As described above, according to the present invention, the movement and elastic deformation of the valve body seat ring in the groove cause the distortion of the valve box, the processing error in the valve box seat, and the shaft in the valve body mounting structure. Uniform sealing can be secured over the entire circumference of the valve seat ring by absorbing misalignment and the like, and the opening and closing operation can be easily performed with a light operating force.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a seal structure of a butterfly valve according to an embodiment of the present invention.

FIG. 2 is a sectional view of a valve body seat ring in the embodiment.

FIG. 3 is an overall vertical sectional view of a conventional butterfly valve.

FIG. 4 is an overall cross-sectional view of a conventional butterfly valve.

FIG. 5 is an enlarged sectional view of a portion A in FIG. 4;

[Explanation of symbols]

 12 valve box seal box 14 valve body 15 valve body seat ring 18 groove 19 slit

Claims (1)

(57) [Scope of request for utility model registration] 1. A valve box seat portion is formed on an inner periphery of a valve box, an annular groove is formed on an outer periphery of a valve body opposed to the valve box seat portion, and a valve body seat ring disposed in the groove portion is formed by a groove portion. It is fitted with an appropriate distance between the bottom surface of the valve body and the inner peripheral edge of the valve body seat ring, and a plurality of slits are provided in the radial direction on the inner peripheral side portion of the valve body seat ring at appropriate intervals in the circumferential direction. Features a butterfly valve seal structure.