JPH11210900A - Sealing structure in ball valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance sealability for a sealing means in a ball valve without using a specific energiging means. SOLUTION: A spherical valve element 5 turnable around a vertical shaft 7 is stored inside a valve chest 3 communicating with a passage 2, and an annular valve seat 14 abutting to the circumferential face of the valve element 5 is arranged between an annular tapered part 11 formed in an upstream or downstream of the valve element 5 in the passage 2 and having a diameter contracted with distance from the valve element 5 and the valve element 5, freely to move to the passage 2 direction. A sealing means 17 having a cylindrical form and formed into a tapered face 19 having its inner circumferential face slidingly contacting with the outer circumferential face of a cylindrical part 13 of the annular valve seat 14, and having the end part in the opposite side of the valve element 5 slidingly contacting with the annular tapered part 11 is provided between a ring part 12 abutting to the circumferential face of the valve element 5 and the annular tapered part 11, and an energizing means 18 for energizing the annular valve seat 14 and the sealing means 17 to a direction opposing each other along the passage 2 is provided between the ring part 12 and the sealing means 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing structure for a ball valve, which can improve the sealing performance of the ball valve with a simple structure.

[0002]

2. Description of the Related Art In a ball valve in which a spherical valve element is accommodated in a valve chamber formed in the middle of a flow path penetrating a valve box, a peripheral portion of the spherical valve element upstream or downstream of the spherical valve element is provided inside the valve chamber. An annular valve seat that is in contact with the surface and the inner peripheral surface of the valve chamber is disposed so that a conveyed material such as fluid or powder does not leak from between the valve chamber and the spherical valve element.

[0003] In particular, in a ball valve in which a high-temperature conveyed material is caused to flow through a flow path, the spherical valve element undergoes thermal expansion, and the pressure contact force between the spherical valve element and the annular valve seat is excessively increased. ,
The spherical valve element may not be able to rotate. Therefore, by making the annular valve seat movable in the direction of the flow path and making the annular valve seat follow the thermal expansion of the spherical valve element, the thermal expansion of the spherical valve element is absorbed and the spherical valve element cannot rotate. May be prevented.

As an example of such a ball valve,
For example, an annular diameter-reducing step is formed on the inner peripheral surface of the flow path on the upstream or downstream side of the spherical valve body, and between the diameter-reducing step and the spherical valve body, the diameter of the spherical valve body is reduced. An annular valve seat having a ring portion abutting on the peripheral surface facing the step portion, and a cylindrical portion extending from the inner end of the ring portion in the flow direction so as to move away from the spherical valve body, and Between the portion and the reduced-diameter step portion, a seal means that is in contact with the outer peripheral surface of the cylindrical portion and the reduced-diameter step portion is arranged. Some devices are provided with biasing means for biasing in opposite directions along the flow path.

[0005]

However, in the above-described ball valve, the urging force of the urging means is increased to prevent the conveyed material from leaking from the annular valve seat into the flow passage. In addition, it is necessary to press the sealing means against the reduced diameter step portion with a strong force. However, since the space between the reduced diameter step portion and the annular valve seat is narrow and it is difficult to provide a large urging means here, the urging force of the urging means is limited.

Further, since the above-mentioned ball valve has no means for pressing the sealing means and the cylinder, there is a possibility that the conveyed material may leak from between the sealing means and the cylinder.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and improves the sealing performance of the sealing means without using any special urging means. It is an object of the present invention to provide a seal structure for a ball valve, which prevents a load from leaking from a container.

[0008]

According to the present invention, the above-mentioned problem is solved as follows. (1) A spherical valve element rotatable around a substantially vertical axis is accommodated in a flow path penetrating a valve chamber of a valve box, and an upstream or downstream side of the spherical valve element on an inner peripheral surface of the flow path. An annular ring portion is formed on at least one of the annular ring portions, the diameter of which decreases as the distance from the spherical valve body decreases, and between the spherical valve body and the annular taper portion, which contacts the peripheral surface of the spherical valve body. And an annular valve seat having a cylindrical portion extending in a direction away from the spherical valve body along the flow path from the inner periphery of the ring portion, and disposed so as to be movable in the flow direction, and the ring portion and the annular portion. Between the tapered portion, a cylindrical shape, the inner peripheral surface is in sliding contact with the outer peripheral surface of the tubular portion of the annular valve seat, and the end opposite to the spherical valve body can be in sliding contact with the annular tapered portion. The sealing means, which is a surface, is disposed so as to be movable in the flow path direction, Between the grayed portion and the sealing means is provided urging means for urging the annular valve seat and the sealing means, along the flow path in opposite directions.

(2) In the above item (1), the tapered surface of the sealing means is formed of a synthetic resin material.

(3) In the above item (2), the sealing means is provided on a cylindrical member formed of a synthetic resin material, and is provided outside the cylindrical member in the axial direction. And a ring member formed by:

[0011]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

A flow path (2) penetrating the valve case (1) in the left-right direction is formed inside the valve case (1), and a central portion of the flow path has a larger diameter than the flow path (2). (3).

The valve chamber (3) contains a spherical valve element (5) having a substantially horizontal through hole (4) aligned with the flow path (2). The lower end of a stem (7) penetrating a vertical shaft hole (6) provided above the valve chamber (3) is engaged with the upper surface of the valve chamber (3).

[0014] Stem (7) by driving means not shown
By rotating, the spherical valve element (5) rotates in the valve chamber (3).

The upstream side of the valve chamber (3) in the flow path (2) (the left side in the figure is defined as the upstream side)
A diameter-reducing step (8) for reducing the diameter in stages is formed. Between the peripheral surface on the upstream side of the spherical valve element (5) and the reduced-diameter stepped portion (8), the first cylindrical inner surface whose right side surface is in contact with the peripheral surface of the spherical valve element (5). An annular valve seat (9) is arranged, and a first annular valve seat is provided.
An annular first sealing means (1) is provided between (9) and the reduced diameter step (8).
0).

Downstream of the valve chamber (3) in the flow path (2),
An annular annular taper (1
1) is formed. Between the downstream peripheral surface of the spherical valve element (5) and the annular tapered part (11), a ring part (12) whose left side surface, which is the inner surface, is in contact with the peripheral surface of the spherical valve element (5). , A cylindrical portion (13) extending from the inner periphery of the ring portion (12) toward the downstream side
The second annular valve seat (14) is disposed.

In the space between the ring portion (12) and the annular tapered portion (11), a ring member (15) made of metal and a cylindrical member (15) made of a synthetic resin material such as graphite or Teflon are provided. 16) and a second sealing means (17) comprising
Between the ring portion (12) of the second annular valve seat (14) and the ring member (15), the second annular valve seat (14) and the ring member (15)
An annular disc spring (1) that urges in the opposite direction along (2)
8) is provided.

The downstream end surface of the tubular member (16) is a tapered surface that slides on the annular tapered portion (11), and the inner peripheral surface of the tubular member (16) is a second annular valve seat (14). It comes into sliding contact with the outer peripheral surface of the cylindrical portion (13).

According to such an embodiment, the spherical valve element
In the closed state (the state shown in the figure) in which the through hole (4) of (5) intersects the flow path (2), when a conveyed material such as a liquid or powder fluid flows from the upstream side to the downstream side, The pressure of the flow is spherical valve (5)
, The spherical valve element (5) is pressed against the second annular valve seat (14), and the space between the spherical valve element (5) and the second annular valve seat (14) is sealed.

When the spherical valve element (5) presses the second annular valve seat (14) toward the annular tapered portion (11), the tapered surface (19) and the annular tapered portion (11) which are in a wedge relationship with each other. Is strongly sealed, and there is almost no possibility that the conveyed material leaks from between the two.

The wedge force at this time causes the cylindrical member (1
6) is pressed toward the cylindrical portion (13) of the second annular valve seat (14), so that the space between the cylindrical member (16) and the second annular valve seat (14) is strongly sealed, and There is almost no risk that the conveyed material will leak out from between.

When a conveyed material such as a liquid or a powder fluid flows from the downstream side to the upstream side, the pressure of the conveyed material causes the spherical valve body
(5) is pressed into contact with the first annular valve seat (9) to seal between the two, so that there is no possibility that the conveyed material leaks from between the two.

Further, even if the spherical valve element (5) undergoes thermal expansion, the second annular valve seat (14) moves toward the annular tapered portion (11), thereby causing the spherical valve element (5) to thermally expand. Absorbs the minute,
The spherical valve element (5) does not become unrotatable due to too high a pressure contact force between the spherical valve element (5) and the second annular valve seat (14).

A second annular valve seat (14) and an annular tapered portion (13) are provided on the upstream side, and a first annular valve seat (9) and a reduced diameter step (8) are provided on the downstream side. You may.

[0025]

According to the present invention, the following effects can be obtained. (a) According to the first aspect of the present invention, for example, when an annular valve seat is provided on the downstream side, when a conveyed material such as a liquid or powder fluid flows from the upstream side to the downstream side, the pressure of the conveyed material As a result, the spherical valve body is pressed toward the annular valve seat, and the space between the spherical valve body and the annular valve seat is sealed. Further, when the spherical valve body is pressed toward the annular valve seat, the sealing means is pressed toward the annular tapered portion by the urging force of the urging means, and the tapered surface and the annular tapered portion that are in a wedge relationship with each other. Since the space between them is strongly sealed, there is almost no possibility that the conveyed material leaks from between the two. Further, the sealing means is pressed against the cylindrical portion of the annular valve seat by the wedge force, so that the sealing portion between the cylindrical portion of the sealing means and the cylindrical portion of the annular valve seat is strongly sealed. There is almost no danger of leakage.

(B) According to the second aspect of the present invention, since the tapered surface of the sealing means easily conforms to the annular tapered portion, a stronger seal can be provided between the tapered surface and the annular tapered portion.

(C) According to the third aspect of the present invention, since a part of the sealing means is a metal ring member, the rigidity of the sealing means is improved.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of an embodiment of the present invention.

[Explanation of symbols]

 (1) Valve box (2) Flow path (3) Valve chamber (4) Through hole (5) Spherical valve body (6) Shaft hole (7) Stem (shaft) (8) Reduced diameter step (9) First Annular valve seat (10) First sealing means (11) Annular taper portion (12) Ring portion (13) Tube portion (14) Second annular valve seat (annular valve seat) (15) Ring member (16) Tube member ( 17) Second sealing means (sealing means) (18) Disc spring (biasing means) (19) Tapered surface

Claims (3)

[Claims] 1. A valve chamber communicating with a flow path in a valve box accommodates a spherical valve element rotatable about a substantially vertical axis, and an upstream or downstream side of the spherical valve element on an inner peripheral surface of the flow path. An annular ring that forms an annular tapered portion that decreases in diameter as it moves away from the spherical valve body on at least one of the sides, and an annular ring that contacts the peripheral surface of the spherical valve body between the spherical valve body and the annular tapered portion. Portion, an annular valve seat having a cylindrical portion extending in a direction away from the spherical valve body along the flow path from the inner periphery of the ring portion, disposed so as to be movable in the flow direction, and the ring portion and Between the annular taper and a cylindrical shape,
A sealing means in which the inner peripheral surface is in sliding contact with the outer peripheral surface of the cylindrical portion of the annular valve seat, and the end on the opposite side to the spherical valve body is a tapered surface that can be in sliding contact with the annular tapered portion, in the flow direction. It is arranged so as to be movable, and further provided between the ring portion and the sealing means is a biasing means for biasing the annular valve seat and the sealing means in opposite directions along the flow path. Seal structure for ball valve. 2. The seal structure for a ball valve according to claim 1, wherein the tapered surface of the sealing means is formed of a synthetic resin material. 3. A sealing member comprising: a cylindrical member formed of a synthetic resin material; and a ring member provided outside of the cylindrical member in the axial direction and abutting on the urging member and formed of metal. 3. The method according to claim 2, wherein
The seal structure in the ball valve as described.