JPS6327597B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a valve seat that is placed in pressure contact with the valve body and the valve body to maintain airtightness, and rotates the valve body. The present invention relates to a ball valve that opens and closes a fluid passage, and in particular, the valve seat is separated from the valve body when the valve body is rotated.

(Prior Art) A cross-sectional view of an example of a conventional ball valve is shown in FIG. In the figure, a spherical valve chamber 1a and a passage 1b communicating with the valve chamber 1a are provided inside a valve body 1. A spherical valve body 2 is disposed in the valve chamber 1a and has a passage 2a connected to the passage 1b.
It is arranged so that it can rotate freely. Furthermore, passage 1b
A seat ring 3 is fitted into the inner cylinder wall of the valve body 2 so as to be slidable in the direction of the passage 1b.
The valve seat 5 is pressed against the valve body 2 and maintained in an airtight state. In addition, 7
is a key that connects the valve body 2 and the rotating shaft 6, and 4 is a gasket that makes the valve body 1 and the seat ring 3 airtight.

Thus, by rotating the rotating shaft 6 and arranging the passage 2a of the valve body 2 and the passage 1b of the valve body 1 in a straight line, the flow passage is opened, and the passage 2a of the valve body 2 is aligned with the passage 2a of the valve body 1. If it is placed perpendicular to the passage 1b, the flow passage will be closed.

By the way, in such a ball valve, since the valve seat 5 is always pressed against the valve body 2, when the valve body 2 is rotated, the valve may be damaged due to wear, galling, or even foreign matter mixed into the fluid. Sheet 5 is susceptible to damage. In particular, in an intermediate opening state from a fully open state to a fully closed state, a part of the valve seat 5 is located facing the passage 2a of the valve body 2,
Galling is likely to occur at the edges of the passage 2a. Further, if the valve body 2 is in an intermediate opening state to restrict the flow rate, the valve seat 5 at the portion of the valve body 2 that corresponds to the edge of the passage 2a is particularly susceptible to damage. This is valve body 2
This is because in the intermediate opening state, fluid pressure imbalance and changes in the flow state occur continuously, and the valve body 2 is in an unstable vibration state.

Therefore, as a technique for eliminating such damage to the valve seat 5, there are techniques proposed in Japanese Patent Publication No. 19776-1977 and Japanese Patent Publication No. 25186-1986.
All of these devices have a structure in which the seat ring 3 is moved so as to be separated from the valve body 2 using fluid pressure when the valve body 2 is opened/closed. It is valid.

However, in these proposed structures, the mechanism for separating the seat ring 3 from the valve body 2 is performed by operating a switching valve provided outside the valve body 1 using fluid pressure within the ball valve. However, it has a large number of parts, a complicated structure, and is expensive. Furthermore, there are many parts that need to be sealed, such as the piping connecting the valve body 1 and the switching valve, and the switching valve, making maintenance management complicated, and damage to the sealing parts can cause serious accidents such as leakage of fluid inside the ball valve to the outside. easy.

Furthermore, at a rotation angle where the valve body 2 is not in a closed state,
As a technique for mechanically separating the seat ring 3 from the valve body 2 to eliminate damage to the valve seat 5, there are techniques proposed in Utility Model Application Publication No. 49-143831 and Japanese Patent Application Publication No. 54-122431. . These techniques have a structure in which the seat ring 3 is appropriately separated from the valve body 2 by a cam disposed on the rotating shaft 6 of the valve body 2.

This structure is simpler than one in which the seat ring 3 is separated from the valve body 2 using fluid pressure, and is particularly suitable for small-sized ball valves.

(Problems to be Solved by the Invention) By the way, the technology proposed in Japanese Utility Model Application Publication No. 49-143831 is to arrange a cam consisting of a long diameter portion and a short diameter portion on both sides of the rotating shaft of the valve body 2. , the long diameter portion is brought into contact with the seat ring 3 and the seat ring 3 is separated by the valve body 2. The seat ring 3, which is separated from the valve body 2, is supported by the long diameter portion of the cam at one point on both sides of the rotation axis of the valve body 2, respectively. For this reason, the seat ring 3 tends to become unstable in the passage, and especially when the valve body 2 is at an intermediate opening degree, the seat ring 3 becomes unstable due to fluid pressure imbalance or changes in the vibration state. There is a problem in that it tends to generate vibrations, which can easily become a factor in generating noise.

Furthermore, the technique proposed in Japanese Patent Application Laid-open No. 122431/1983 is to bring a roller connected to the seat ring 3 into contact with cams disposed on both sides of the rotating shaft of the valve body 2. Similar to the technique proposed in Japanese Utility Model Application Publication No. 49-143831, there is a problem in that the seat ring 3 is unstable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ball valve that has a simple structure and has a stable seat ring when separated from the valve body.

(Means for Solving the Problem) In order to achieve the above object, the ball valve of the present invention maintains airtightness by disposing a valve seat that is pressed against the valve body and the valve body. , in a ball valve that opens and closes a fluid passage by rotating the valve body, a seat ring for holding the valve seat is slidably disposed on an inner cylindrical wall of the passage, and the seat ring is attached to the valve body. an elastic member is disposed to elastically bias the seat ring toward the valve body, and two protrusions are provided on each side of the rotation shaft of the valve body on the side of the valve body of the seat ring, separated in the circumferential direction and the axial direction of the rotation shaft. and a cam portion having an annular shape and having two recesses into which the protrusions fit respectively at a rotation angle at which the valve body is in a closed state is provided on each side of the rotation axis of the valve body. has been done.

(Function) Therefore, at a rotation angle where the valve body is not in a closed state, the two protrusions provided circumferentially apart from the seat ring come into contact with the annular peripheral wall of the cam part, so that the seat ring Even when separated from the valve body, the seat ring is supported at two points and remains stable.

(Description of Embodiments) Embodiments of the present invention will be described below with reference to FIGS. 1 to 7. FIG. 1 is an overall sectional view of an embodiment of the ball valve of the present invention, and FIG.
FIG. 3 is an enlarged sectional view of the main part of the device shown in FIG. 1 in a closed state; FIG. 3 is a view taken in the direction of arrow A in FIG.
The figure is a view of the sliding seat 9 in FIG.
The figure is an enlarged sectional view of the sliding seat 9 in FIG. 3 taken in the direction of arrow C, FIG. It is a view taken along arrow A in the figure. In FIGS. 1 to 7, the same members as those in FIG. 8 are given the same reference numerals, and redundant explanations will be omitted.

An annular cam portion 8 is fixed to each of the upper and lower sides of the rotating shaft of the valve body 2 by bolts 13, concentrically with the valve body 2. A sliding seat 9 is fixed to the seat ring 3 facing the cam portion 8 with bolts 12, and is brought into contact with the peripheral wall of the cam portion 8 by the elasticity of an elastic member 11. The contact surface of the sliding seat 9 is provided with two semicircular protrusions 9a and 9b, and the peripheral wall of the cam portion 8 is provided with a position where the valve body 2 faces the sliding seat 9 at a closed angle. recesses 8a, into which the protrusions 9a, 9b can fit;
8b is provided. Note that the protrusions 9a and 9b
The recesses 8a and 8b are arranged so as not to be vertically aligned in the direction of the rotation axis of the cam part 8, and spaced apart in the circumferential direction. In addition, the pin 10 and the elastic member 1
1 are alternately arranged at equal pitches in the circumferential direction of the seat ring 3 between the seat ring 3 and the valve body 1, and prevent the seat ring 3 from rotating in the circumferential direction. The entire circumference of the seat ring 3 is configured to be pressed against the valve body 2 with uniform pressure.

In FIGS. 2 and 3, the valve body 2 is in the rotation angle of the closed state, and the concave portions 8a, 8b have protrusions 9a,
9b is inserted, the seat ring 3 is pressed and moved in the direction of the valve body 2 by the elastic member 11, and the valve seat 5
is in close contact with the valve body 2. From this state, valve body 2
When rotated by operating the rotating shaft 6, the protrusions 9a, 9b move into the recesses 8a, 8 as shown in FIGS. 6 and 7.
b, the seat ring 3 is pushed and moved in the direction of separation from the valve body 2 against the elasticity of the elastic member 11, and the valve seat 5 is separated from the valve body 2.
The valve body 2 is rotated in a state where the valve seat 5 is not in contact with the valve body 2.

In such a configuration, the two protrusions 9a, 9b
are arranged separately in the circumferential direction of the rotation axis of the valve body 2, and are provided on both sides of the rotation axis of the valve body 2, so that even when the seat ring 3 is separated from the valve body 2, the 2 It is supported by two protrusions 9a and 9b and is in a stable state. Therefore, even if an imbalance in fluid pressure or a change in the flow state occurs when the valve body 2 is at an intermediate opening degree, the seat ring 3 does not vibrate or generate noise.

In the above embodiment, the cam portion 8 is formed as a separate member from the valve body 2, but the present invention is not limited to this, and the cam portion 8 may be formed integrally with the valve body 2. Similarly, the seat ring 3 and the sliding seat 9 may be formed as separate members or may be formed integrally. Furthermore, the protrusions 9a and 9b are not limited to the semicircular shape as in the above embodiment, but may also be trapezoidal or triangular, and if the recesses 8a and 8b are shaped so that these protrusions 9a and 9b can fit into them. good.

(Effects of the Invention) As explained above, according to the ball valve of the present invention, the seated valve separated from the valve body is in a stable state, so it is not affected by fluid pressure imbalance or changes in the flow state. Does not cause vibration,
It has an excellent effect of not generating noise or the like.

[Brief explanation of the drawing]

FIG. 1 is an overall cross-sectional view of one embodiment of the ball valve of the present invention, FIG. 2 is an enlarged cross-sectional view of the main part in the closed state of FIG. 1, and FIG. A
FIG. 4 is a view in the direction of arrow B of the sliding seat in FIG. 3, FIG. 5 is an enlarged cross-sectional view of the sliding seat in FIG. The figure is an enlarged cross-sectional view of the main part in the open state of FIG. 1, and FIG.
FIG. 8 is a sectional view of an example of a conventional ball valve. 1: Valve body, 2: Valve body, 3: Seat ring, 5:
Valve seat, 8: cam part, 8a, 8b: recessed part,
9: Sliding seat, 9a, 9b: Projection, 11: Elastic member.

Claims (1)

[Claims] 1. A ball valve that maintains airtightness by placing a valve seat pressed against the valve body between the valve body and the valve body, and holding the valve seat in a ball valve that opens and closes a fluid passage by rotating the valve body. A seat ring is slidably disposed on the inner cylindrical wall of the passage, an elastic member is disposed to elastically bias the seat ring toward the valve body, and an elastic member is disposed on the valve body side of the seat ring to Two protrusions are provided on each side of the rotational shaft of the valve body, separated in the circumferential direction and axial direction of the rotational axis, and each of the two protrusions on both sides of the rotational axis of the valve body is annular and has a shape that prevents the valve body from being closed. 1. A ball valve comprising: a cam portion having two recesses into which the protrusion portions fit respectively at a certain rotation angle.