JPH0710136Y2 - Ball valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a ball valve used for piping for transporting water, oil, gas, etc. to open and close the flow of fluid.

(Prior Art) In a ball valve equipped with a ball seat in which a metal ring is fitted on the outer peripheral surface, leakage between the metal ring and the ball seat and leakage from the metal ring and the valve body are prevented. However, conventionally, the structure shown in the partial sectional view of FIG. 5 has been used.

That is, the flow passage 22 of the valve body 21 is formed with the enlarged diameter step portion 24 that opens to the ball 23 side, and the enlarged diameter step portion 24 is formed from the ball 23 side from the ball seat 25, the retainer 26, and the retainer gland 27. And the annular leaf spring 28 are sequentially mounted, the cylindrical metal ring 29 is fitted on the outer peripheral surface 25a of the ball seat 25, and the gasket 30 is attached to the portion of the retainer 26 facing the ball seat 25 and the metal ring 29. The gasket 30 is mounted and prevents leakage between the ball seat 25 and the metal ring 29.

Further, a step portion 26a for gland is formed on the outer peripheral side of the side surface of the retainer 26 facing the retainer gland 27, and an annular packing 31 is loaded into this, and the annular packing 31 is compressed by the annular protrusion 27a of the retainer gland 27. Thus, the leakage between the retainer 26 and the valve main body 21, and hence the leakage between the metal ring 29 and the valve main body 21, is prevented.

(Problems to be solved by the invention) However, in this structure, the gasket 30 and the annular packing 31 are
In addition to the ball seat 25, the retainer 26, and the annular leaf spring 28, the retainer gland 27 is required, and the structure is complicated and the cost is high.

The present invention has been devised in view of the above-mentioned prior art, and in a ball valve equipped with a ball seat in which a cylindrical metal ring is fitted on the outer peripheral surface, leakage from between the metal ring and the ball seat and It is intended to solve the problem that the structure for preventing the leakage from between the metal ring and the valve body is complicated, and thus the cost becomes high.

Configuration of the Invention (Means for Solving the Problems) The present invention has the following configuration in order to solve the above problems.

That is, a ball valve equipped with a pair of ball seats in which a cylindrical metal ring is fitted on the outer peripheral surface, and a diameter-increasing stepped portion that opens to the ball side of the inflow passage and the outflow passage of the valve body is formed. Then, the ball seat, the retainer, and the annular spring are sequentially mounted from the ball side to the expanded diameter step portion, and a right-angled step portion is provided on a side surface of the ball seat facing the retainer, and a side surface of the retainer facing the ball seat. A right-angled step portion that forms a rectangular annular space such as a substantially square or rectangular cross-section that opens in the outer circumferential direction between the ball seat fitted to the right-angled step portion of the ball seat and fitted with the metal ring. The packing was installed in the annular space.

In this case, the packing is preferably made of expanded graphite.

Further, it is preferable that the right-angled step portion formed on the retainer is formed such that the side surface on the retainer side of the annular space is a convex or concave annular curved surface. It is preferable that the side surface of the annular space on the ball seat side is formed into a convex or concave annular curved surface.

Further, an outer peripheral groove having an abutting surface is formed on the ball side of a carbon ball seat made of carbon and a carbon compound, and one end surface of the above-mentioned metal ring is abutted on the abutting surface to burn the metal ring in the outer peripheral groove. It may be configured to be fitted by fitting.

(Operation) An annular space opened in the outer peripheral direction is formed between the retainer and the ball seat in which a cylindrical metal ring is fitted on the outer peripheral surface, and the packing is attached to the annular space. At the same time as stopping the leakage between the metal ring and the ball seat, it also stops the leakage between the metal ring and the expanded step portion of the valve body. Compared with the structure, the structure is extremely simple, and moreover, it is possible to reliably seal.

In this case, if the packing is made of expanded graphite and the ball sheet is made of carbon, a ball valve having particularly excellent heat resistance and chemical resistance is obtained.

Also, when the side surface of the annular space on the retainer side or the ball seat side is formed into a convex or concave annular curved surface, the annular packing having a substantially square cross section is strongly compressed between the inner diameter side and the outer diameter side or the middle. The part is strongly compressed to further enhance the sealing effect of the packing against the above-mentioned two leaks.

Further, if the metal ring is shrink-fitted into the outer peripheral groove of the carbon ball seat and mounted, and one end is abutted against the abutting surface, the metal ring can be prevented from coming off.

In the structure of the present invention, an all-metal ball seat can be used instead of the carbon or resin ball seat fitted with the metal ring.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial vertical sectional view showing an embodiment of the ball valve of the present invention.

In the figure, 1 is a ball valve, 2 is a ball valve 1.
Of the present invention, 3 is a ball seat, 4 is a metal ring, 5 is a retainer, 6 is an annular leaf spring, and 7 is a ball of a valve body.

In this example, the ball seat 3 is made of carbon or resin, and a cylindrical metal ring 4 is fitted to the ball seat 3a. The valve body 2 is formed with an enlarged diameter step portion 2b that opens to the ball 7 side of the inflow / outflow passage 2a. The enlarged diameter step portion 2b is formed from the ball 7 side to the ball seat 3, the retainer 5, and the annular leaf spring. 6 and 6 are installed in sequence. In FIG. 1, only one of these inflow side or outflow side is shown and the other is omitted.

Right side step 3b on the side surface 3b of the ball seat 3 facing the retainer 5
3c is provided, and a side surface 5a of the retainer 5 facing the ball seat 3 is fitted to the right-angled step portion 3c of the ball seat 3 and is opened in the outer peripheral direction with the ball seat 3 fitted with the metal ring 4. A right-angled step portion 5b forming an annular space 8 having a substantially square cross section is provided.

A packing 9 is attached to the annular space 8, and in this embodiment, the packing 9 is made of expanded graphite. It should be noted that it is arbitrary how to form the right angled step portion 3c of the ball seat 3 and the right angled step portion 5b of the retainer 5, and thus whether the annular space 8 formed as a result is on the ball seat 3 side or the retainer 5 side. , FIG. 1 shows the latter case, and FIG. 2 is a partial longitudinal sectional view showing the former case.

The annular leaf spring 6 is given a required elastic deformation when the ball valve 1 is assembled, and due to its resilience, properly compresses the packing 9 and applies contact surface pressure to the ball 7 of the ball seat 3. There is.

In FIG. 1, 10 is a stem, 11 is a stem bearing, 12 is a thrust washer, and 13 is a gland packing.

FIG. 3 (a) shows a right-angled step portion 5b formed on the retainer 5,
FIG. 3 is a partial vertical cross-sectional view in which the side surface 8a of the annular space 8 on the side of the retainer 5 is formed into a concave annular curved surface, and FIG. 3 (b) is also a side surface 8a having a convex annular curved surface. FIG. 3 (c) is a partial vertical cross-sectional view in the case of forming
The right-angled step portion 3c formed on the ball seat 3 is attached to the annular space 8
FIG. 3D is a partial cross-sectional view in which the side surface 8b on the side of the ball seat 3 is formed into a concave annular curved surface, and FIG. 3D shows the right-angled step portion 3c formed in the ball seat 3 in the annular space 8 FIG. 7 is a partial cross-sectional view of the side surface 8b on the side of the ball seat 3 formed to have a convex annular curved surface.

Next, the operation of the embodiment shown in FIGS. 1 to 3 will be described.

Since the annular space 8 opening in the outer peripheral direction is formed between the ball seat 3 in which the cylindrical metal ring 4 is fitted on the outer peripheral surface 3a and the retainer 5, and the packing 9 is attached to the annular space 8. The packing 9 prevents leakage between the metal ring 4 and the ball seat 3 and at the same time prevents leakage between the metal ring 4 and the enlarged diameter step portion 2b of the valve body 2. Compared to the conventional structure that stops leakage at two points separately,
The structure is simple and the seal can be surely made.

Further, as shown in FIGS. 3 (a) to (d), one or both side surfaces 8a, 8b of the annular space 8 on the side of the retainer 5 have a convex or concave annular curved surface. The intermediate portion of the rectangular annular packing 9 having a substantially square shape or a rectangular shape is strongly compressed, or the inner diameter side and the outer diameter side are strongly compressed to further enhance the sealing effect of the packing 9 against the above-mentioned two leaks. It will be.

In the structure of the present embodiment, the ball seat 3 made of all metal can be used instead of the ball seat 3 made of carbon or resin in which the metal ring 4 is fitted.

FIG. 4 is a partial vertical cross-sectional view showing still another embodiment of the present invention. As shown in FIG. 4, an outer peripheral groove 3e having a stepped abutting surface 3d is formed on a carbon ball seat 3. By fitting the metal ring 4 into the outer peripheral groove 3e by shrink fitting, it is possible to reliably prevent the metal ring 4 from coming off.

Advantageous Effects of Invention According to the ball valve of the present invention, in a ball valve equipped with a ball seat in which a metal ring is fitted on the outer peripheral surface,
While achieving a simple structure and low cost, it is possible to reliably prevent both leaks between the metal ring and the ball seat and between the metal ring and the valve body with the packing. can do. Also, with this structure, not only carbon or resin ball seats but also metal ball seats can be used as they are for the ball seat fitted with a metal ring, so that the application range is wide.

[Brief description of drawings]

1 to 4 show an embodiment of the ball valve of the present invention. FIG. 1 is a partial longitudinal sectional view showing one embodiment of the ball valve, and FIG. 2 shows another embodiment. Partial longitudinal sectional views, and FIGS. 3A to 3D are partial longitudinal sectional views when the sectional shape of the annular space of the embodiment shown in FIG. 1 is changed,
FIG. 4 is a partial vertical sectional view showing still another embodiment, and FIG. 5 is a partial vertical sectional view showing a conventional example of a ball valve having a ball seat fitted with a metal ring. 1 ... Ball valve, 2 ... Valve body 2a ... Flow path, 2b ... Expanding step section 3 ... Ball seat, 3a ... Outer peripheral surface 3b ... Side surface, 3c ... Right section 3d ... Projection For the time being, 3e …… Outer peripheral groove 4 …… Metal ring 5, …… Retainer 5a …… Side surface, 5b …… Right-angled step 6 …… Annular leaf spring, 7 …… Ball 8 …… Annular space, 8a, 8b… … Side 9 …… Packing

Claims (4)

[Scope of utility model registration request] 1. A ball valve equipped with a pair of ball seats, each of which has a cylindrical metal ring fitted on an outer peripheral surface thereof, wherein the diameter-increasing step is open on the ball side of an inflow passage and an outflow passage of a valve body. The ball seat, the retainer, and the annular spring are sequentially mounted from the ball side to the expanded-diameter step portion,
A right-angled step portion is provided on a side surface of the ball seat facing the retainer, and an outer circumference is formed between the side surface of the retainer facing the ball seat and the metal sheet fitted with the right-angled step portion of the ball seat. Direction is provided with a right-angled step portion that forms a rectangular annular space such as a substantially square or rectangular cross-section that is open in the direction, and packing is installed in this annular space, and it projects toward the ball side of a carbon ball seat made of carbon and carbon compounds. A ball valve, wherein an outer peripheral groove having a contact surface is formed, and one end surface of the above-mentioned metal ring is abutted against this contact surface and the metal ring is fitted into the outer peripheral groove by shrink fitting. 2. The ball valve according to claim 1, wherein the packing is made of expanded graphite. 3. The ball valve according to claim 1 or 2, wherein the right-angled step portion formed on the retainer is formed such that a side surface of the annular space on the retainer side has a convex or concave annular curved surface. 4. The right-angled step portion formed on the ball seat is formed so that the side surface of the annular space on the ball seat side has a convex or concave annular curved surface. Ball valve.