JPH11159637A - Seat ring for ball valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely maintain a seal property. SOLUTION: In a ball valve respectively fitting a seat ring 4 into a pair of annular grooves 3 formed between a valve chest in a valve body and both end circulation holes to bring the seat ring 4 into contact with a peripheral surface of a valve element 2, a seat ring main unit 17 with the seat ring 4 into contact with the peripheral surface of the valve element 2 and an elastic seat part 18 bonded from an internal peripheral surface over to a back surface of the seat ring main unit 17 are provided. In a back surface of the elastic seat part 18, an elastic protrusion part 18a into contact with a side surface of the annular groove is integrally formed, in a front surface of the elastic seat part 18, a seal surface 18b into contact with a peripheral surface of the valve element 2 is formed, an O ring 20 is provided, which is fitted into an annular recessed part 19 formed in a peripheral surface of the seat ring main unit 17 to come into contact with an internal peripheral surface of the annular groove, and in an internal peripheral surface of the elastic seat part 18, a metal- made liner 21 is internally fitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat ring of a ball valve excellent in preventing fluid leakage.

[0002]

2. Description of the Related Art As an example of a ball valve, as shown in FIG. 3, a ball-shaped valve body 2 is rotatably disposed in a valve chamber 1a of a valve box 1, and both the valve chamber 1a and the valve chamber 1a of the valve box 1 are connected to each other. Flow holes 1b, 1c
There is a seat ring 4 fitted in a pair of annular grooves 3 formed in an inner peripheral surface between the valve body 2 and the outer peripheral surface of the valve body 2. By operating the manual handle 5 fixed to the valve element 2 from the valve open state (see FIG. 3) communicating with the flow holes 1b and 1c of the valve box 1, the valve element 2 is rotated 90 °, The valve can be closed.

Conventionally, as an example of the seat ring 4, there is one shown in FIG. This has a seat ring main body 7 in contact with the outer peripheral surface of the valve body 2, and a rubber elastic sheet portion 8 adhered from the inner peripheral surface to the back surface of the seat ring main body 7. A projection 8a is formed integrally with the side surface of the annular groove 3 and a sealing surface 8b is formed on the front surface of the elastic seat portion 8 to abut on the outer peripheral surface of the valve body 2, and the outer peripheral surface of the seat ring body 7 is formed. O which is fitted into the annular recess 9 formed in the
A ring 10 is provided.

[0004]

In the above construction, the sealing surface 8b of the elastic sheet portion 8 is brought into contact with the outer peripheral surface of the valve body 2 to prevent the so-called leakage of the sealing surface, and the O-ring 10 is connected to the annular groove 3 by the annular groove 3. A so-called back surface leakage is prevented by making contact with the inner peripheral surface of the seal member, and the structure is such that the seal surface pressure is proportional to the pressure, so that the sealing performance can be maintained from a low pressure to a high pressure. However, when the pressure becomes high, the sealing surface pressure increases, and the frictional force between the seat ring 4 and the valve body 2 increases. Therefore, for example, when the ball valve is opened from the fully closed state, the elastic seat portion 8 is elastically deformed due to its low rigidity, and the sealing performance is reduced, and the elastic deformation amount sometimes increases, and the elastic seat portion 8 is increased. 8 could be damaged.

[0005] In view of the above problems, an object of the present invention is to provide a seat ring of a ball valve that can reliably maintain sealing performance.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a ball-shaped valve element is rotatably disposed in a valve chamber of a valve box. In a ball valve in which a seat ring fitted into a pair of annular grooves formed between both end communication holes and an outer peripheral surface of the valve body, the seat ring contacts the outer peripheral surface of the valve body. Having a seat ring body in contact therewith, an elastic sheet portion adhered from the inner peripheral surface to the back surface of the seat ring body,
An elastic projection is formed integrally with a back surface of the elastic seat portion to abut against a side surface of the annular groove, and a sealing surface is formed on a front surface of the elastic seat portion to abut an outer peripheral surface of the valve body. An O-ring that is fitted into an annular recess formed on the outer peripheral surface of the elastic sheet portion and abuts on an inner peripheral surface of the annular groove, and a metal liner is internally fitted on an inner peripheral surface of the elastic sheet portion. And

[0007] According to the above construction, the elastic projection is in contact with the side surface of the annular groove, and the sealing surface of the elastic sheet portion is in contact with the outer peripheral surface of the valve body by its elastic force. Surface leakage can be prevented, and back leakage can be prevented because the O-ring is in contact with the inner peripheral surface of the annular groove. Also, since the inner peripheral surface of the elastic seat portion is reinforced by the metal liner, when the ball valve is opened from the fully closed state in a state where the sealing surface pressure is large and the frictional force between the seat ring and the valve body is increased. However, since the elastic deformation amount of the elastic sheet portion is small, the elastic sheet portion is not damaged, and the sealing property can be reliably maintained. Further, a ball valve having good sealing performance and operability from low pressure to high pressure can be obtained by simply adding a simple improvement to the conventional seat ring.

According to a second aspect of the present invention, in the first aspect of the present invention, a reinforcing flange is integrally provided on an outer peripheral surface of the liner. According to the above configuration, since the deformation of the liner is prevented by the reinforcing flange, the elastic sheet portion can be more reliably reinforced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of a ball valve according to an embodiment of the present invention.
The seat ring main body 17 abuts on the outer peripheral surface of the valve body 2.
And an elastic sheet portion 18 adhered from the inner peripheral surface to the back surface of the seat ring main body 17.
8, an elastic projection 18a is integrally formed on the back surface,
A sealing surface 18b is formed on the front surface of the elastic seat portion 18 to be in contact with the outer peripheral surface of the valve body 2, and is fitted into an annular concave portion 19 formed on the outer peripheral surface of the seat ring main body 17 so that the annular groove 3 is formed.
An O-ring 20 is provided in contact with the inner peripheral surface of the elastic sheet portion 18, and a metal liner 21 is fitted on the inner peripheral surface of the elastic sheet portion 18.

The seat ring body 17 is formed of polytetrafluoroethylene (PTFE).
The sealing surface 17a is in contact with the outer peripheral surface of the valve body 2. The elastic sheet portion 18 is formed of rubber (for example, acrylonitrile-butadiene rubber (NBR)), and is integrally formed with the seat ring main body 17 by vulcanization bonding.

According to the above configuration, as shown in FIG. 2, the elastic projection 18a is projected rearward from the back surface of the elastic sheet portion 18 by a small distance α, and the sealing surface 18b is formed in an arc shape. The sealing surface 1 of the seat ring body 17
As shown in FIG. 1, the elastic projection 18a abuts against the side surface of the annular groove 3 so that the elastic surface 18a abuts on the sealing surface 1 by its elastic force.
8b abuts against the outer peripheral surface of the valve body 2, thereby preventing leakage of the seal surface.

The O-ring 20 is formed of rubber (for example, acrylonitrile-butadiene rubber (NBR)), and its sealing surface 20a is
1, the sealing surface 20a is in contact with the inner peripheral surface of the annular groove 3 to prevent leakage of the back surface as shown in FIG. .

The liner 21 is made of stainless steel, and as shown in FIG.
a is protruded integrally and is formed in a substantially L-shaped cross section. According to the above configuration, since the inner peripheral surface of the elastic seat portion 18 is reinforced by the liner 21, the ball valve is removed in a state where the sealing surface pressure is large and the frictional force between the seat ring 4 and the valve body 2 is increased. Even when the elastic sheet portion 18 is opened from the fully closed state, the amount of elastic deformation of the elastic sheet portion 18 is small, the elastic sheet portion 18 is not damaged, the sealing property can be reliably maintained, and the reinforcing flange portion 21a Since the deformation of the liner 21 is prevented, the elastic sheet portion 18 can be reinforced more reliably.

When manufacturing the seat ring 4,
A liner 21 is incorporated on the inner peripheral side of the elastic sheet portion 18,
The elastic sheet portion 18 and the seat ring main body 17 may be bonded by vulcanization.

In this case, the seat ring body 1 described above is used.
7, by setting the cross-sectional shape of the seat ring 4 including the elastic sheet portion 18 and the liner 21 to be the same as the cross-sectional shape of the conventional liner-less seat ring 4 (see FIG. 4). The molding die for use can be used as it is, and the production cost can be reduced.

[0016]

According to the first aspect of the present invention, the elastic projection is brought into contact with the side surface of the annular groove, whereby the sealing surface of the elastic sheet portion comes into contact with the outer peripheral surface of the valve body by its elastic force. As a result, leakage of the sealing surface can be prevented, and leakage of the back surface can also be prevented because the O-ring is in contact with the inner peripheral surface of the annular groove. Also, since the inner peripheral surface of the elastic seat portion is reinforced by the metal liner, when the ball valve is opened from the fully closed state in a state where the sealing surface pressure is large and the frictional force between the seat ring and the valve body is increased. However, since the elastic deformation amount of the elastic sheet portion is small, the elastic sheet portion is not damaged, and the sealing property can be reliably maintained. Further, a ball valve having good sealing performance and operability from low pressure to high pressure can be obtained by simply adding a simple improvement to the conventional seat ring.

According to the second aspect of the invention, since the deformation of the liner is prevented by the reinforcing flange, the elastic sheet portion can be reinforced more reliably.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of a ball valve according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the seat ring.

FIG. 3 is a cross-sectional view of the ball valve.

FIG. 4 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve box 2 Valve body 3 Annular groove 4 Seat ring 17 Seat ring main body 18 Elastic seat part 18a Elastic projection part 18b Seal surface 19 Annular groove 20 O-ring 21 Liner 21a Reinforcement flange of liner

Claims (2)

[Claims] 1. A ball-shaped valve element is rotatably disposed in a valve chamber of a valve box, and is fitted in a pair of annular grooves formed between the valve chamber in the valve box and both end communication holes. In a ball valve in which a seat ring is in contact with an outer peripheral surface of the valve body,
The seat ring has a seat ring main body abutting on an outer peripheral surface of the valve body, and an elastic seat portion adhered from an inner peripheral surface to a back surface of the seat ring main body, and the annular groove is provided on a back surface of the elastic seat portion. An elastic projection is formed integrally with the side surface of the seat ring, and a sealing surface is formed on the front surface of the elastic seat portion to contact the outer peripheral surface of the valve body. A seat ring for a ball valve, wherein an O-ring is provided so as to be fitted into contact with an inner peripheral surface of the annular groove, and a metal liner is internally fitted on an inner peripheral surface of the elastic seat portion. 2. A seat ring for a ball valve according to claim 1, wherein a reinforcing flange is integrally provided on an outer peripheral surface of said liner.