JPH05141543A - Butterfly valve with metal valve seat - Google Patents

Abstract

PURPOSE:To give continuity to the seat surface of the seat portion provided on the inner periphery of a valve box without being peripherally discontinued at the valve shaft supporting portion of the valve box, eliminate the need for providing a bearing device in a special seal structure on the valve shaft supporting portion and ensure sealing ability while realizing a simple structure at a low cost. CONSTITUTION:The seat surface 6 of the seat portion 5 on the inner periphery of a valve box 1 is mated with the peripheral face of a virtual cylinder R inclined to the axial center P of a cylindrical flow passage 2 on both a plane perpendicular to a valve shaft 3 and a plane parallel to the valve shaft 3. The seat surface 6 is offset against a valve shaft supported position in the valve box 1 toward the axial center.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal valve seat butterfly valve used for controlling the opening and closing of various fluid passages such as waterworks.

[0002]

2. Description of the Related Art As a butterfly valve of this type, the one disclosed in, for example, Japanese Patent Publication No. 55-18297 is conventionally known, which will be described with reference to FIG. In FIG. 4, reference numeral 1 is a valve box having a cylindrical flow path 2.
A valve shaft 3 that is orthogonal to the axis P of the cylindrical flow path 2 is rotatably supported in the. Reference numeral 4 is a disc-shaped valve body which is attached to the valve shaft 3 and opens and closes the cylindrical flow path 2 by rotation of the valve shaft 3. An annular seat portion 5 is formed on the inner peripheral surface of the valve box 1 so as to correspond to the valve shaft 3, and the seat portion 5 has a plane orthogonal to the valve shaft 3 (sheet surface in FIG. 4).
The seat surface 6 is formed so as to coincide with the peripheral surface of the virtual cylinder R0 having the axis Q that is inclined with respect to the axis P of the cylindrical flow path 2. On the other hand, on the outer peripheral surface of the valve body 4, there is formed a seat surface 7 which is in close contact with the seat surface 6 in a fully closed state where the valve body 4 is perpendicular to the axis P of the cylindrical flow path 2. There is.

In the butterfly valve having the above structure, when the valve shaft 3 is rotated to rotate the valve body 4 to a position parallel to the axis P of the cylindrical flow path 2, the cylindrical flow path 2 is formed. Open to allow fluid delivery. Further, if the valve body 4 is rotated until it is orthogonal to the axis P of the cylindrical fluid 2, the valve body 4
The seat surface 7 of (3) comes into close contact with the seat surface 6 on the valve box 1 side, and the cylindrical flow path 2 is fully closed.

[0004]

According to the conventional butterfly valve having the above-mentioned structure, the valve shaft 3 is supported by the valve box 1 at a position where it penetrates the seat portion 5 on the valve box 1 side. ,
The seat surface 6 of the seat portion 5 is discontinuous in the circumferential direction. For this reason, a bearing device having a special seal structure is required in the penetrating portion (supporting portion) of the valve shaft 3, which has the drawbacks of complicating the overall structure and increasing the cost.

The present invention has been made to solve the above-mentioned problems, and while maintaining continuity in the circumferential direction on the seat surface to simplify the structure of the valve shaft supporting portion and suppress cost increase, It is an object of the present invention to provide a metal valve seat butterfly valve capable of ensuring a sealing property.

[0006]

In order to achieve the above object, the present invention provides a valve box having a cylindrical flow passage, an inner peripheral surface of which is provided with an annular seat portion, and the cylindrical flow passage. A valve shaft rotatably supported by the valve box so as to cross the shaft center; and a disc-shaped valve body attached to the valve shaft to open and close the cylindrical flow path by rotation of the valve shaft, In a butterfly valve configured to bring the seat surface formed on the outer peripheral surface of the valve body into close contact with the seat surface formed on the seat portion at the fully closed position of the valve body, in a direction orthogonal to the valve shaft. The seat surface is aligned with the peripheral surface of a virtual cylinder inclined with respect to the axis in both the plane and the plane parallel to the valve shaft, and the seat surface is described above with respect to the valve shaft bearing position in the valve box. It is displaced in the axial direction.

[0007]

According to the butterfly valve having the above-described structure, the seat surface is not divided in the circumferential direction by the valve shaft, so that a bearing device having a special seal structure at the valve shaft bearing portion is not necessary, and the structure is simple. And cost reduction are achieved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1, 2, and 3 are a front view, a plan sectional view, and a side sectional view, respectively, showing a butterfly valve according to an embodiment of the present invention. The same parts as those of the conventional example shown in FIG. The reference numerals are given and their explanations are omitted.

In FIGS. 1 and 2, the seat surface 6 of the annular seat portion 5 formed on the inner peripheral surface of the valve box 1 is
The cylindrical flow path 2 is formed in a plane orthogonal to the valve shaft 3 (the plane of FIG. 2).
Of the valve shaft 3 as shown in FIG.
Is inclined so as to coincide with the peripheral surface of an imaginary cylinder R having an axis S inclined with respect to the axis P in a plane parallel to the plane (the paper surface of FIG. 3). With respect to the valve shaft supporting position, the seat portion 5 has a constant length l in the direction of the axis P.
Only (Figs. 2 and 3) are deviated. Reference numerals 8 and 9 in the figure denote bearing portions provided on the valve casing 1 and supporting the upper and lower ends of the valve shaft 3, respectively.

In the butterfly valve having the above structure, the valve shaft 3
Since the opening / closing operation of the valve body 4 with respect to the cylindrical flow path 2 by the rotating operation is the same as the conventional one, the description thereof will be omitted. Here, the virtual cylinder R tilted in a plane orthogonal to the valve shaft 3 is further tilted in a plane parallel to the valve shaft 3, and the seat surface 6 is aligned with the peripheral surface of the virtual cylinder R, and the seat is seated. Since the surface 6 is offset from the valve shaft supporting position, the seat surface 6 is not interrupted by the valve shaft 3 in the circumferential direction and continuity is maintained. Therefore, it is not necessary to provide a bearing device or the like having a special sealing function at the bearing portion of the valve shaft 3, the structure of this portion is simplified, and the manufacturing cost can be reduced.

[0011]

As described above, according to the present invention, the seat surface of the seat portion of the valve box is formed of a virtual cylinder which is inclined in both the plane orthogonal to the valve axis and the plane parallel to the valve axis. Since it matches the peripheral surface, the continuity of the entire surface of the seat is maintained,
It is no longer necessary to provide a bearing device with a special seal structure for the bearing part of the valve stem of the valve shaft, thus simplifying the structure and reducing the cost while ensuring good sealability in the fully closed state. can do.

[Brief description of drawings]

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

FIG. 2 is a plan sectional view showing a butterfly valve according to an embodiment of the present invention.

FIG. 3 is a side sectional view showing a butterfly valve according to an embodiment of the present invention.

FIG. 4 is a plan sectional view showing a conventional butterfly valve.

[Explanation of symbols]

 1 Valve box 2 Cylindrical flow path 3 Valve shaft 4 Valve body 5 Seat part 6, 7 Seat surface P Shaft center R Virtual cylinder

Claims (1)

[Claims] 1. A valve box having a cylindrical flow path and an annular seat portion provided on the inner peripheral surface thereof, and rotatably supported by the valve box so as to intersect the axis of the cylindrical flow path. A valve shaft and a disc-shaped valve body attached to the valve shaft to open and close the cylindrical flow path by the rotation of the valve shaft, and the seat surface formed on the outer peripheral surface of the valve body is provided with the valve body. In a butterfly valve configured to be in close contact with the seat surface formed in the seat portion in the fully closed position, the shaft is provided in both a plane orthogonal to the valve axis and a plane parallel to the valve axis. A metal valve seat characterized in that the seat surface is aligned with the peripheral surface of a virtual cylinder inclined with respect to the center, and the seat surface is displaced in the axial direction with respect to the valve shaft bearing position in the valve box. Butterfly valve.