JP3352597B2 - Ball valve seat ring - Google Patents

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 FIG. 7 shows an example of a conventional ball valve. In this ball valve, a ball-shaped valve element 2 is rotatably disposed inside a valve chamber 1a of a valve box 1. Valve room 1 of valve box 1
The annular groove 3 is formed in each of the peripheral portions of the opening portions of the valve box ports 1b and 1c that are opened in a.
Seat rings 4 that are in contact with the outer peripheral surface of the valve body 2 are fitted respectively.

As shown in FIG. 7, a manual handle 5 fixed to the valve body 2 is operated from a valve opened state in which the communication hole 2a of the valve body 2 and the valve box ports 1b and 1c of the valve box 1 are communicated. By rotating the valve body 2 by 90 °, the valve can be brought into the closed state.

As shown in FIG. 8, the seat ring 4 is generally made of polytetrafluoroethylene [PTF
E (registered trademark Teflon)], and had poor elasticity. For this reason, when the fluid pressure is small, it is difficult to sufficiently obtain the surface pressure on the sealing surface 4a of the seat ring 4 over the entire circumference, and the sealing surface 4a and the valve body 2
Or a so-called leakage of the sealing surface occurs, or the back surface 4b of the seat ring 4 and the side surface 3a of the annular groove 3
A so-called back-side leakage, in which a fluid leaks from between the two, may occur.

Therefore, as shown in FIG. 9, the seat ring 4 is made of a polytetrafluoroethylene seat ring main body 4A and a nitrile rubber [NBR (acrylonitrile-butadiene) formed integrally with the inner peripheral surface of the seat ring main body 4A. It is considered that the elastic sheet portion 4B made of rubber) is formed and the sealing surface 4c of the elastic sheet portion 4B is brought into contact with the outer peripheral surface of the valve body 2.

As shown in FIG. 10, a seat ring 4 is provided with a ring-shaped holder 6, a seat ring main body 4A made of polytetrafluoroethylene fitted in an annular recess formed in the front surface of the holder 6, and a holder. An O-ring 7 fitted into an annular recess formed on the outer peripheral surface of
The annular groove 3 is inserted into a recess formed on the back of the holder 6.
And a spring 8 pressed against the side surface 3a of the second member.

[0007]

However, in the conventional structure described above, the sealing surface 4a of the seat ring main body 4A is pressed against the outer peripheral surface of the valve body 2 by the spring 8, thereby preventing the leakage of the sealing surface and the O-ring. Although the back surface leakage is prevented by contacting the inner peripheral surface 3b of the annular groove 3 with the groove 7, the structure is complicated, the number of parts is large, and the production cost is high.

The present invention solves the above-mentioned problems, and
It is an object of the present invention to provide a seat ring of a ball valve having a simple structure, a small number of parts, a low manufacturing cost, and capable of preventing leakage of a sealing surface and a back surface.

[0009]

In order to solve the above-mentioned problems, a seat ring of a ball valve according to the present invention has a ball-shaped valve element rotatably disposed in a valve chamber of a valve box, and is opposed to the valve element. In a ball valve in which an annular groove is formed at the peripheral edge of the opening of the valve box port to be fitted and a seat ring that abuts on the outer peripheral surface of the valve body is fitted into the annular groove, the seat ring abuts on the outer peripheral surface of the valve body. A seat ring main body, an O-ring fitted into an annular recess formed on the outer peripheral surface of the seat ring main body and abutting against an inner peripheral surface of the annular groove, and an O-ring located on the inner peripheral surface side of the seat ring main body. An inner peripheral side elastic seat portion abutting on the outer peripheral surface, and a back side elastic projection portion located on the back side of the seat ring main body and abutting on the side surface of the annular groove are provided.

According to the above configuration, even when the fluid pressure is small, the sealing surface of the inner peripheral surface elastic sheet portion is formed by the elastic force by the back side elastic projection abutting against the side surface of the annular groove. While the O-ring is in contact with the inner peripheral surface of the annular groove to prevent leakage of the back surface, the O-ring is in contact with the outer peripheral surface of the valve body to prevent leakage of the sealing surface. Moreover, when the seat ring is mounted on the valve box, the inner peripheral side elastic seat portion, the rear side elastic projection portion and the seat ring main body can be handled as a single member, so that the mounting operation can be simplified and the structure can be simplified. Manufacturing cost can be reduced by simplification and reduction of the number of parts.

In the present invention, the back side elastic projections are formed intermittently at intervals in the circumferential direction of the seat ring body. According to this configuration, since the rear-side elastic projections are formed intermittently, the rear-side elastic projections are liable to be elastically deformed, and the elastic force of the rear-side elastic projections causes the sealing surface of the inner peripheral-side elastic seat to be closed to the valve body. Can be reliably brought into contact with the outer peripheral surface of the main body.

According to the seat ring of the ball valve of the present invention, a ball-shaped valve body is rotatably disposed in a valve chamber of a valve box, and an annular groove is formed in a peripheral portion of an opening of a valve box port facing the valve body. In the ball valve in which a seat ring abutting on the outer peripheral surface of the valve body is fitted into the annular groove, the seat ring is located on the inner peripheral surface side of the seat ring body abutting on the outer peripheral surface of the valve body. An inner peripheral side elastic seat portion abutting on the outer peripheral surface of the valve body, a rear side elastic projection portion located on the back side of the seat ring main body and abutting on the side surface of the annular groove, and an outer peripheral surface side of the seat ring main body Located on a circular cross section with seat ring book
Projecting outward from the outer peripheral surface of the body,
An inner peripheral elastic sheet portion, a rear elastic protrusion, and an outer peripheral elastic sheet portion which are formed integrally with the seat ring main body with an integral structure. .

According to this configuration, when the seat ring is mounted on the valve box, the seat ring main body, the inner peripheral side elastic seat portion, the back side elastic projection portion, and the outer peripheral side elastic seat portion can be handled as a single member. Further, the mounting operation can be further simplified.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. Components that perform the same operations as those described above with reference to FIGS. 7 to 10 are denoted by the same reference numerals, and description thereof is omitted.

FIG. 1 shows a main part of a ball valve according to an embodiment of the present invention. A seat ring 4 has an elastic seat portion 11 integrally formed on an inner peripheral surface and a back surface of a seat ring main body 10. The O-ring 12 is held on the outer peripheral surface of the seat ring body 10. The seat ring main body 10 is formed of polytetrafluoroethylene (PTFE), and its seat surface 10a is in contact with the outer peripheral surface of the valve body 2 and a semicircular cross section in which the elastic seat portion 11 fits on the back surface. And an annular concave portion 10c having a rectangular cross section into which the O-ring 12 is fitted is formed on the outer peripheral surface.

The elastic sheet portion 11 is made of nitrile rubber [NB
R (acrylonitrile-butadiene rubber)], which is formed integrally with the seat ring main body 10 by vulcanization bonding, and has an inner peripheral elastic sheet portion 11A and a rear elastic protrusion 11B. I have.

As shown in FIG. 2, the sealing surface 11a of the inner peripheral side elastic seat portion 11A is formed in an arc shape, and protrudes forward by a slight distance α from the sealing surface 10a of the seat ring main body 10 so as to protrude. 2 is in contact with the outer peripheral surface. The rear side elastic projection 11B is formed in a ring shape having a circular cross section and is fitted into the annular concave portion 10b, and the rear end surface 11b is slightly spaced β from the rear surface of the elastic sheet portion 11.
And abuts on the side surface 3 a of the annular groove 3.

The O-ring 12 is made of nitrile rubber [NB
R (acrylonitrile-butadiene rubber)], and is fitted into the annular concave portion 10c. The sealing surface 12a of the annular groove 3 protrudes outward from the outer peripheral surface of the seat ring body 10 by a slight interval t. It is in contact with the inner peripheral surface 3b.

According to the above-described structure, even when the fluid pressure is small, the back side elastic projection 11B is formed on the side surface 3 of the annular groove 3.
a, the sealing surface 11a of the inner peripheral side elastic sheet portion 11A comes into contact with the outer peripheral surface of the valve body 2 by its elastic force, thereby preventing leakage of the sealing surface.

The sealing surface 12a of the O-ring 12 is in contact with the inner peripheral surface 3b of the annular groove 3 to prevent back leakage. The back side elastic projection 11B also prevents back side leakage. In this case, the seat ring 4 is composed of the O-ring 12, the seat ring main body 10 integrally formed with the inner peripheral elastic sheet portion 11A and the rear elastic protrusion 11B, and has a simple structure and a reduced number of parts. Low cost and low production cost.

In the above-described embodiment, the back side elastic projection 11B is formed in a ring shape. However, as shown in FIG.
The back side elastic projection 11B may be formed intermittently at intervals in the circumferential direction. According to this configuration, the back side elastic projection 11B is easily elastically deformed, and the sealing surface 11a of the inner peripheral side elastic seat 11A can be reliably brought into contact with the outer peripheral surface of the valve body 2 by the elastic force.

FIG. 4 shows another embodiment of the present invention. The seat ring 4 includes a seat ring main body 10 abutting on the outer peripheral surface of the valve body 2 and an inner peripheral surface of the seat ring main body 10. And an elastic sheet portion 11 having a substantially U-shaped cross section integrally formed on the back surface and the outer peripheral surface. The elastic sheet portion 11 is formed of nitrile rubber [NBR (acrylonitrile-butadiene rubber)], is formed integrally with the seat ring main body 10 by vulcanization bonding, and has an inner peripheral elastic sheet portion 11A, a rear elastic protrusion. It has an integral structure consisting of a portion 11B and an outer peripheral side elastic sheet portion 11C.

As shown in FIG. 5, the sealing surface 11a of the inner peripheral side elastic seat portion 11A is formed in an arc shape and protrudes forward by a slight distance α from the sealing surface 10a of the seat ring main body 10 so as to protrude. 2 is in contact with the outer peripheral surface. The rear side elastic projection 11B is formed in a ring shape having a circular cross section and is fitted into the annular concave portion 10b, and the rear end surface 11b is slightly spaced β from the rear surface of the elastic sheet portion 11.
And abuts on the side surface 3 a of the annular groove 3.

The outer peripheral side elastic sheet portion 11C is formed in a circular cross section and is fitted in the annular concave portion 10c, and its sealing surface 11c is located outwardly of the outer peripheral surface of the seat ring main body 10 by a slight interval t. The inner peripheral surface 3 of the annular groove 3 which protrudes
b.

According to the above configuration, even when the fluid pressure is small, the back side elastic projection 11B is formed on the side surface 3a of the annular groove 3.
, The sealing surface 11a of the inner peripheral side elastic sheet portion 11A is brought into contact with the outer peripheral surface of the valve body 2 by its elastic force, thereby preventing leakage of the sealing surface. In addition, the sealing surface 11c of the outer peripheral side elastic sheet portion 11C is
b to prevent back leakage. The back side elastic projection 11B also prevents back side leakage.

In this case, since the inner peripheral side elastic sheet portion 11A, the rear side elastic projection portion 11B and the outer peripheral side elastic sheet portion 11C are formed integrally with the seat ring main body 10, the mounting operation can be easily performed. The structure is simple, the number of parts is small, and the manufacturing cost can be reduced. In the above embodiment, the back side elastic projection 11B is formed in a ring shape, but as shown in FIG.
May be formed intermittently at intervals in the circumferential direction.

[0027]

As described above, according to the present invention, even when the fluid pressure is small, the inner peripheral surface side elastic sheet is made to have the elastic force by contacting the back side elastic projection with the side surface of the annular groove. The sealing surface of the portion can be pressed against the outer peripheral surface of the valve body to prevent leakage of the sealing surface, and the O-ring can prevent leakage of the back surface. By forming the inner peripheral side elastic sheet portion and the rear side elastic projection portion integrally with the seat ring main body, mounting work can be easily performed, the structure is simple, the number of parts is small, and the production cost is reduced. be able to. Also, when the rear side elastic projection is formed intermittently, the rear side elastic projection is easily elastically deformed,
By the elastic force, the sealing surface of the inner peripheral surface side elastic sheet portion can be reliably brought into contact with the outer peripheral surface of the valve body. Furthermore, by integrally forming the inner peripheral side elastic sheet portion, the rear side elastic projection portion, and the outer peripheral side elastic sheet portion on the seat ring main body, the mounting operation can be performed more easily, and the number of parts can be reduced to reduce the cost. Can be manufactured.

[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 transverse sectional view showing a modified example of the seat ring.

FIG. 4 is a cross-sectional view showing a main part of a ball valve according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of the seat ring.

FIG. 6 is a transverse sectional view showing a modified example of the seat ring.

FIG. 7 is a cross-sectional view of the ball valve.

FIG. 8 is a cross-sectional view showing an example of the related art.

FIG. 9 is a cross-sectional view showing another example of the related art.

FIG. 10 is a cross section showing still another example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve box 2 Valve body 3 Annular groove 4 Seat ring 10 Seat ring main body 11A Inner peripheral side elastic seat part 11B Back side elastic projection part 11C Outer peripheral side elastic seat part 12 O-ring

Claims (3)

(57) [Claims] A ball-shaped valve element is rotatably disposed in a valve chamber of a valve box, and an annular groove is formed in a peripheral portion of an opening of a valve box port facing the valve element. In a ball valve in which a seat ring abutting on an outer peripheral surface is fitted, the seat ring is fitted into an annular concave portion formed on an outer peripheral surface of the seat ring main body and an annular recess formed on the outer peripheral surface of the seat ring body. An O-ring contacting the inner peripheral surface of the groove, an inner peripheral elastic seat portion located on the inner peripheral surface side of the seat ring body and abutting on the outer peripheral surface of the valve body, and an O-ring located on the back side of the seat ring main body. A seat for a ball valve, comprising: a rear side elastic projection that abuts a side surface of the annular groove; and an inner peripheral side elastic seat portion and a rear side elastic projection formed integrally with the seat ring body. ring. 2. A ball-shaped valve element is rotatably disposed in a valve chamber of a valve box, and an annular groove is formed in a peripheral portion of an opening of a valve box port facing the valve element. In a ball valve in which a seat ring abutting on the outer peripheral surface is fitted, the seat ring is located on the inner peripheral surface side of the seat ring main body and the seat ring main body abutting on the outer peripheral surface of the valve body. An inner-peripheral-side elastic seat portion that abuts, a back-side elastic protrusion that is located on the back side of the seat ring main body and abuts the side surface of the annular groove, and a cross-sectional circle that is located on the outer peripheral surface side of the seat ring main body;
Protruding outward from the outer peripheral surface of the seat ring body
An outer peripheral side elastic sheet portion which contacts the inner peripheral surface of the annular groove.
A seat ring for a ball valve , wherein the inner peripheral side elastic seat portion, the back side elastic projection portion, and the outer peripheral side elastic seat portion have an integral structure and are integrally formed on a seat ring main body. 3. The seat ring for a ball valve according to claim 1, wherein the back side elastic projections are formed intermittently at intervals in a circumferential direction of the seat ring main body.