JP2002106725A - Shaft sealing structure for butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft sealing structure of a butterfly valve capable of sufficiently displaying sealing performance in the butterfly valve separating a valve box from a valve box sheet. SOLUTION: A valve rod 18 is arranged by being passed through a through hole 13a of the cylindrical valve box sheet 13 arranged on the valve box 12. A valve element 22 is provided at the inside of the valve box sheet 13. Valve element side shaft sealing seal materials 25 are provided around the valve rod 18 on both sides of the valve element 22. A valve element sheet 24 in slidable contact with the valve box sheet 13 is provided at a peripheral edge part of the valve element 22. A ring-shaped valve box side shaft sealing seal material 26 which is abutted on the valve sheet 13 and is made of an elastic material is arranged on a through hole 13a of the valve box sheet 13. A seal material pressing part 20 is provided at a lower end of a bush 20. A tapered surface 26a formed on an inner periphery of the valve box side shaft sealing seal material 26 and a tapered surface 20b formed on an outer periphery of the seal material pressing part 20 are made to abut each other. A boss part 19 is provided with a fastening means 28 for pressing the seal material pressing part 20a on the valve box side shaft sealing seal material 26 via the bush 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing structure for a butterfly valve, and more particularly to a technique for sealing a gap between a valve stem and a valve box sheet in a watertight manner.

[0002]

2. Description of the Related Art In a metal sheet butterfly valve as shown in FIG. 5, for example, a valve element 2 is provided inside a valve box 1 so as to be rotatable around the axis of a valve rod 3, and a metal element is provided around the valve element 2. A valve body sheet 4 made of a material is provided, and a valve box sheet (not shown) that is in sliding contact with the valve body sheet 4 is provided on the inner surface of the valve box 1.

The valve stem 3 is disposed so as to pass through the boss portion 5 of the valve box 1, and a rubber shaft sealing material 8 is disposed between the valve body-side shaft sealing ring 6 and the bush 7. By tightening the annular holding plate 9 disposed on the other end side with the fastening bolt 10, the shaft sealing material 8 is pressed through the holding plate 9 and the bush 7 to seal the valve stem 3.

[0004]

By the way, in a metal sheet butterfly valve mounted on a pipeline, a force acts on the valve box 1 due to fluctuations in water pressure or ground, and the valve box may be deformed. When the valve box sheet is integrally formed on the inner peripheral surface of the valve box 1 as in the related art, the valve box sheet is deformed as the valve box 1 is deformed, and the valve box sheet and the valve body sheet 4 are deformed. There is a problem that water does not come into contact with water tightly to cause water leakage, or the valve body 2 is restrained by deformation of the valve box sheet. For this reason, it is conceivable that the valve box sheet is formed separately from the valve box 1. However, the above-mentioned conventional shaft sealing structure cannot exhibit sufficient sealing performance.

The present invention has been made to solve the above-mentioned problem, and provides a butterfly valve shaft sealing structure capable of exhibiting sufficient sealing performance even in a butterfly valve having a valve box and a valve box sheet as separate bodies. The purpose is to:

[0006]

In order to solve the above problems, a shaft sealing structure of a butterfly valve according to the present invention comprises a cylindrical valve box sheet made of a thin metal material inside a valve box. A valve box sealing material made of an elastic material is arranged concentrically between the inner surface of the valve box and the outer peripheral surface of the valve box sheet, and is inserted into a boss portion of the valve box and a through hole of the valve box sheet to form a valve. A rod is arranged, and a valve body is rotatably provided around the axis of the valve rod in the valve box sheet.
A valve body-side shaft sealing seal material made of a metal material is provided around the valve shaft on both sides of the valve body in the axial direction of the valve shaft, and a valve body sheet made of a metal material that slides on the inner peripheral surface of the valve box sheet in a watertight manner. Along the periphery of the valve body, provided between the valve body side shaft seal materials on both sides,
Insert a bush that holds the valve stem rotatably into the boss,
A ring-shaped valve box-side shaft sealing material made of an elastic material that comes into contact with the valve box sheet and the valve body-side shaft sealing material is disposed in the through hole of the valve box sheet. A seal material pressing portion disposed between the valve shaft and the valve shaft is provided, a taper surface is formed on an inner periphery of the valve box side shaft sealing seal material, and a taper surface is formed on an outer periphery of the seal material pressing portion, and a valve box side shaft seal is formed. The seal member and the seal member pressing portion are arranged so as to be in contact with both tapered surfaces, and the boss portion is provided with a fastening means for pressing the seal member press portion against the valve box side shaft seal member through a bush. It is.

[0007] With the above construction, the valve element has a valve stem with a valve stem extending between a fully closed position where the valve element sheet slides against the valve box sheet and a fully opened position where the valve element is parallel to the flow path axis. Rotate around my heart. By sealing the gap between the inner surface of the valve box and the outer peripheral surface of the valve box sheet with the valve box sealing material, when fully opened, the entire amount of fluid flowing into the valve box passes through the internal flow path of the valve box sheet.

On the other hand, by tightening the tightening means and pressing the sealing member pressing portion to the valve box side shaft sealing seal material via the bush, the valve box side shaft sealing seal material is made watertight to the valve body side shaft sealing seal material. In addition to the sliding contact, the wedge action of the tapered surface causes the valve box-side shaft sealing seal material to spread radially outward, and a surface pressure is generated against the inner peripheral surface of the through hole of the valve box sheet to exert sealing performance. At the time of rotation of the valve element, the valve element-side shaft sealing material rotates while being in water-tight sliding contact with the valve box-side shaft sealing material. Therefore, the fluid flowing through the internal flow path of the valve box sheet does not leak around the valve stem.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A metal sheet butterfly valve according to an embodiment of the present invention will be described below with reference to the drawings. 1 to 4, a metal seat butterfly valve 1 is shown.
1 has a valve box sheet 13 arranged inside a valve box 12,
The valve box sheet 13 is made of a cylindrical thin metal material.
It is provided concentrically with one channel axis and with a predetermined gap S between each other.

Between the inner surface of the valve case 11 and the outer peripheral surface of the valve case sheet 13, a pair of valve case O-rings 14 are disposed on the upstream and downstream sides of the valve case sheet 13. The valve box O-ring 14 is mounted in an annular groove 15 formed on the inner surface of the valve box 11. A stopper 16 is arranged adjacent to the upstream end and the downstream end of the valve box sheet 13. The stopper 16 locks the valve box sheet 13 in the axial direction of the flow path. 11 fixed.

The valve stem 18 passes through a boss 19 of the valve box 11 and a through hole 13a of the valve box sheet 13 in a direction perpendicular to the axial direction of the flow path. It is held rotatably. A plurality of O-rings 21 are arranged on the inner peripheral surface and the outer peripheral surface of the bush 20 to seal between the valve stem 18 and the boss 19.

The valve body 22 includes the valve stem 1 inside the valve box sheet 13.
8 is rotatably arranged around the axis, and the pin 23 is
It is connected to. The valve body 22 is provided with a valve body sheet 24 at a peripheral portion. The valve body sheet 24 is made of a metal material, and the valve box sheet 1 is formed on a valve body sheet surface 24a formed on an outer peripheral surface thereof.
No. 3 is in water-tight sliding contact with the valve box seat surface 13b. The valve body sheet 24 has a shape inclined at a predetermined angle with respect to the cross section of the valve box flow path.

Between the valve body 22 and the bush 20, there is provided a ring-shaped valve body-side seal seal material 25 made of a metal material and a valve box-side shaft seal material 26 made of an elastic material of ethylene tetrafluoride resin.
And are arranged. The valve body-side shaft seal material 25 is made of a valve stem 18.
Are disposed on both sides of the valve element 22 in the axial direction, and the valve element sheet 24 is provided between the two valve element-side shaft sealing materials 25.

The valve box-side shaft seal material 26 is made of the valve box sheet 13.
And a tapered surface 26a on the inner periphery.
Is formed. The valve box-side shaft sealing material 26 may be formed into a single piece as shown in FIG. At the lower end of the bush 20, a sealing member pressing portion 20a is provided between the valve box side shaft sealing member 26 and the valve rod 18, and a tapered surface 20b is formed on the outer periphery of the sealing member pressing portion 20a.
The valve box-side shaft seal material 26 and the seal material pressing portion 20 are arranged so as to abut on both tapered surfaces 26a and 20b.
Note that the seal material pressing portion 20a may be integrated with the bush 20 or may be separate.

At the other end of the bush 20, an annular holding plate 27 is arranged, and the holding plate 27 is attached to the boss 19 with a tightening bolt 28. By tightening the tightening bolt 28, the valve box-side shaft seal 26 is pressed by the seal pressing section 20 a via the holding plate 27 and the bush 20.

The operation of the above configuration will be described below. The valve box O-ring 14 is provided between the inner surface of the valve box 12 and the valve box sheet 1.
By sealing the gap S with the outer peripheral surface of the valve 3, the entire amount of the fluid flowing into the valve box 12 passes through the internal flow path of the valve box sheet 13.

By driving the valve stem 18 to rotate in the forward or reverse direction, the valve body 22 is turned at an angle of 90 degrees around the axis of the valve stem within the valve seat 13 between the fully closed position and the fully opened position. The valve body sheet surface 24a of the valve body sheet 24 is brought into water-tight sliding contact with the valve case sheet surface 13b of the valve case sheet 13 at the fully closed position to close the internal flow path of the valve case sheet 13.

The valve box sheet 13 is separate from the valve box 12,
Since there is a predetermined gap S between the two, even when the valve box 12 is deformed due to the water pressure or the fluctuation of the ground and the valve box 12 is deformed, the valve box sheet 13 is not deformed. Its shape is preserved. For this reason, the valve box sheet 13 contacts the valve body sheet 24 in a watertight manner while maintaining the consistency of the seat surface, so that no water leakage occurs and the valve body 22 is not restrained.

On the other hand, by tightening the tightening bolt 28, the valve box-side shaft seal 26 is pressed by the seal pressing section 20a via the pressing plate 27 and the bush 20. As a result, the valve box-side shaft sealing sill 26 spreads radially outward due to the wedge action of both tapered surfaces 20b and 26a, and a surface pressure is generated on the valve box sheet 13 and the sealing material pressing portion 20a to improve the sealing performance. When the valve element 22 rotates, the valve element-side shaft sealing seal material 25 is
It rotates while sliding against water. Therefore, the fluid flowing through the internal flow path of the valve box sheet 13 does not leak around the valve stem 18.

[0020]

As described above, according to the present invention, the valve-box-side shaft sealing material spreads radially outward due to the wedge action of the tapered surface, and a surface pressure is generated against the valve-box sheet to exert the sealing performance. Therefore, at the time of rotation of the valve body, the valve body-side shaft seal material rotates while sliding on the valve case-side shaft seal material in a watertight manner, and the fluid flowing through the internal flow path of the valve box sheet flows around the valve rod. No water leakage.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view showing the metal seat butterfly valve.

FIG. 3 is a sectional view of a main part of the metal seat butterfly valve.

FIG. 4 is a perspective view showing another embodiment of the valve box-side shaft sealing material of the metal sheet butterfly valve.

FIG. 5 is a schematic view showing a conventional metal seat butterfly valve.

[Description of Signs] S gap 11 metal sheet butterfly valve 12 valve box 13 valve box sheet 13a through hole 13b valve box seat surface 14 valve box O-ring 15 annular groove 16 stopper 17 bolt 18 valve rod 19 boss portion 20 bush 20a sealing material Pressing part 20b Tapered surface 21 O-ring 22 Valve 23 Pin 24 Valve seat 24a Valve seat 25 Valve shaft seal seal 26 Valve box shaft seal 26a Tapered surface 27 Presser plate 28 Tightening bolt

Claims (1)

[Claims] A cylindrical valve box sheet made of a thin metal material is disposed concentrically with a flow channel axis inside a valve box, and an elastic material is provided between an inner surface of the valve box and an outer peripheral surface of the valve box sheet. And a valve stem is inserted through the boss part of the valve box and the through hole of the valve box sheet, and the valve body is rotatable in the valve box sheet around the axis of the valve stem. A valve body made of a metal material is provided on both sides of the valve body in the axial direction of the valve shaft, the valve body-side shaft sealing material made of a metal material is provided around the valve shaft, and the inner peripheral surface of the valve box sheet is slidably contacted with the inner peripheral surface of the valve box sheet. A seat is provided between the valve body-side shaft seal materials along both sides of the valve body, a bush for rotatably holding the valve rod is inserted into the boss, and the valve box sheet and the valve are inserted into the through holes of the valve box sheet. A valve box-side shaft seal made of a ring-shaped elastic material that is in contact with the body-side shaft seal is arranged, and the valve box-side shaft seal is provided at the lower end of the bush. A sealing material pressing portion disposed between the sealing member and the valve rod, forming a tapered surface on the inner periphery of the valve box side shaft sealing material, and forming a tapered surface on the outer periphery of the sealing material pressing portion,
Tightening in which the valve box-side shaft seal material and the seal material pressing portion abut on both tapered surfaces and press the seal material press portion against the valve box side shaft seal material via the bush on the boss portion. A shaft sealing structure for a butterfly valve, characterized in that a means is provided.