JPH09242902A - Two-set type three-way ball valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an inner leak caused by the pressure difference of fluid and to prevent a ball seat from being permanently deformed to deteriorate sealing performance by fixing a ball received in a body on a rotary shaft in a two-seat type three-way ball valve used for an air conditioner. SOLUTION: A projecting part 3a having two parallel planes at the bottom part of a stem 3 is formed and considerably tightly fitted in a recessed groove 2a of a ball 2 and the ball 2 is joined to the stem 3 with a bolt 4. When the pressure at a pipe joining end 8a is higher than that at the other pipe joining ends 8b, 8c, for example, the ball 2 is pressed to the left by the pressure difference but, since the ball 2 is joined to the stem 3 and is fixed on a rotary shaft, it can not be moved. Therefore, the ball seat 5 remains in a pressure welding state at the pipe joining end 8a side to prevent a leakage from the joining end 8a to a body cavity 8d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-sided seat type three-way ball valve mainly used for cold and hot water piping of air conditioning equipment.

[0002]

2. Description of the Related Art A three-way ball valve of this type has three pipe connection ends, one of which is an inflow port and two of which are outflow ports, and a fluid from the outflow port is directed to either of the outflow ports. It is a ball valve that is switched to flow or is switched to flow the fluid from any one of the inflow ports to the outflow port with one of them as the outflow port and two of them as the inflow port.

FIG. 4 is a vertical cross-sectional view showing an example of a conventional two-face sheet type three-way ball valve, which has three pipe connecting ends 21, 22 and 23, and the pipe connecting end 23 flows through. The ball 24 is rotated by the stem 25 so that the fluid from the inflow port 23 flows to either the outflow port 21 or 22 with the pipe connection ends 21 and 22 as the inflow port and the outflow port as the outflow port, and the port 24a of the ball 24 is set as illustrated. To the pipe connection end 21 or to the pipe connection end 22.

Alternatively, the pipe connection end 23 is used as an outflow port, and the pipe connection ends 21 and 22 are used as inflow ports, and the inflow port 21 or 22 is used.
The ball 24 is rotated by the stem 25 so that the fluid from any one of them flows to the outlet 23, and the port 24a of the ball 24 is directed toward the pipe connection end 21 or toward the pipe connection end 22 as shown in the figure. Or

In FIG. 4, reference numerals 26 and 27 designate balls and seats, and the ball 24 designates these ball seats 26.
And 27. The three-way ball valve shown in FIG. 4 is a vertical type in which the pipe connecting end 23 is provided below the stem 25, and the three pipe connecting ends 2 are provided.
The plane containing the center lines of 1, 22 and 23 also contains the center line of the stem 25.

FIG. 5 is a longitudinal sectional view of a two-way ball valve shown for comparing and explaining the operation of the three-way ball valve shown in FIG. 4, in which the ball 32 is supported by ball seats 33 and 34. The valve is open. FIG.
FIG. 4 is a vertical sectional view showing a state where the ball valve 31 is closed.

In FIG. 5, the fluid is on the right side of the pipe connecting end 3
Assuming that the flow is flowing from 5 to the pipe connection end 34 on the left side, the pressure at the pipe connection end 35 is higher than the pressure at the pipe connection end 36 in the valve closed state shown in FIG. Is pushed to the left, the left ball seat 33 is pushed by the ball 32 and is slightly deformed while being strongly pressed against the ball 32 and the body 37 to completely seal between them.

At this time, the ball 32 slightly moves to the left due to the slight compressive deformation of the ball seat 33. Therefore, the ball seat 34 on the right side often comes out of contact with the ball 32 and the seat retainer 38 so that the pipe connection end 35 and the body cavity 39 communicate with each other. However, since the two-way ball valve 31 is completely sealed by the ball seat 33 as described above, the valve closed state is maintained.

At the connecting portion between the ball 32 and the stem 40, a convex shape 40a having two parallel flat surfaces is formed at the lower end of the stem 40, and the convex shape 40a is formed in the concave groove 32a provided at the upper portion of the ball 32. In the fitted state and the valve closed state as shown in FIG. 6, the ball 32 can be moved from the upstream side to the downstream side by the fluid pressure without being obstructed by the stem 40.

In the two-sided seat type three-way ball valve shown in FIG. 4, the balls 24 are supported by the two ball seats 26 and 27 like the two-way ball valve 31 shown in FIGS. 5 and 6. , For example, in FIG.
If the pressure at is higher than the pressure at the pipe connection ends 21 and 23, this pressure difference will push the ball 24 to the left and there will be some play at the connection with the stem 25 which will cause the movement to the left. The ball seat 26 is pushed by the ball 24 and slightly deformed by compression.

By the movement of the ball 24, the pressure-bonded state of the ball seat 27 on the right side to the ball 24 and the seat retainer 28 is released, and the pipe connection end 22 and the body cavity 29 are brought into communication with each other. The body cavity 29 is separated from the pipe connecting end 21 by the ball seat 26, but is not directly connected to the pipe connecting end 23 because a ball seat is not provided between the body cavity 29 and the pipe connecting end 21. Therefore, the fluid leaking from the pipe connecting end 22 to the cavity 29 flows into the pipe connecting end 23.

In this case, the above operation is the same regardless of which of the pipe connection ends 21 and 23 is the inflow port or the outflow port, the pipe connection end 23 is the inflow port, and the pipe connection end 21 is the outflow port. In some cases, the fluid leaking from the above-mentioned pipe connecting end 22 through the cavity 29 to the pipe connecting end 23 flows to the pipe connecting end 21.

FIG. 7 is a cross-sectional view showing a state in which the balls 24 of the two-face seat type three-way ball valve shown in FIG. 4 are slightly rotated. In this state, port 2 of ball 24
Since 4a rotates and moves with respect to the ball seat 26, the area of the ball seat 26 for supporting the balls 24 is narrow as can be seen from the drawing.

As described above, when the pressure at the pipe connecting end 22 is higher than the pressure at the pipe connecting ends 21 and 23, the ball 24 is pushed to the left by the difference in the pressures and the ball seat 26 has a small area. Since this ball 24 is supported, only that portion locally deforms permanently, and the sealing performance deteriorates.

As described above, in the conventional two-sided seat type three-way ball valve, internal leakage is likely to occur due to the pressure difference of the fluid, and local permanent deformation of the ball seat causes the sealability to deteriorate. It has some problems, and in order to solve or alleviate these problems, a four-sided seat type three-way ball valve with four ball seats is made, but it has a complicated structure and a large size. In addition, it is very expensive and is rarely used except in special cases.

[0016]

SUMMARY OF THE INVENTION The present invention has two main problems described above in the conventional two-sided seat type three-way ball valve, namely, internal leakage is likely to occur due to the pressure difference of the fluid, and the ball seat is It is intended to provide a two-side seat type three-way ball valve which solves the problem that the sealability is deteriorated due to local permanent deformation.

[0017]

In order to achieve the above-mentioned object, the present invention is configured to be fixed on the rotation axis housed in the body. In this case, the balls may be connected to the stem by fitting and bolting and fixed on the axis of rotation, or the balls may be fixed on the upper side by fixing the lower part to the body. The cylindrical member fitted to the lower port of the ball may be fixed on the rotation axis.

Since the two-sided seat type three-way ball valve of the present invention is constructed as described above, the lower pipe connecting end of the vertical three-way ball valve and the side pipe connecting end of the horizontal three-way ball valve are connected. Except for the fact that the pressure at any one of the pipe connection ends is higher than the pressure at the other pipe connection end and the ball is pushed to one side due to this pressure difference, the ball is fitted and bolted or the stem is moved upward. The ball does not move because it is fixed on the axis of rotation by a tubular member or the like that is fixed to the body by fitting with the lower part of the ball and is fitted into the lower port of the ball.

Therefore, on the side of the pipe connection end where the pressure is high, the pressure-bonding state of the ball seat mounted between the ball and the body or the seat retainer does not change, and the leakage into the body cavity does not occur.

Further, even if the ball is rotated and the area of the ball seat for supporting the ball is narrowed, the ball does not move, so that it is not compressed to cause local permanent deformation of the ball seat and the sealing property is improved. It does not lower.

Further, unlike the floating ball type, the two-sided seat type three-way ball valve of the present invention does not press the ball to the downstream side ball seat by fluid pressure, but it does not work on the back surface of the ball seat. Since the O-ring is attached, this completely prevents back leakage at the ball seat portion on the upstream side of the ball, increases the elastic force that presses the ball seat onto the ball, and reliably seals on the upstream side. be able to.

When the ball is connected to the stem by fitting and bolting, the stem is completely prevented from popping out, and the stem popping-out preventing part as in the conventional three-way ball valve is not provided. Not necessary.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a two-sided sheet type 3 of the present invention.
1 is a vertical sectional view showing an embodiment of a one-way ball valve,
Is a ball valve, 2 is a ball, 3 is a stem, 4 is a bolt, 5 and 6 are ball seats, 7 is an O-ring, 8 is a body, and 9 is a seat retainer. A convex portion 3a having two parallel flat surfaces is formed on the lower end portion of the stem 3, and the convex portion 3a is fitted into a concave groove 2a provided on the upper portion of the ball 2 relatively tightly. The ball 2 is bolted to the stem 3 by using, and the ball 2 is coupled to the stem 3 so that the ball 2 is fixed on its rotation axis.

FIG. 2 is a partial cross-sectional view showing the ball 2 and the stem 3 joined together by using the bolt 4 shown in FIG. 1 in a cross section including the center line of the stem 3 perpendicular to the cross section of FIG. is there.

FIG. 3 is a vertical cross-sectional view showing another embodiment of the two-sided seat type three-way ball valve of the present invention, in which 11 is this ball valve, 12 is a ball, 13 is a stem, and 14 is a cylindrical shape. Members 5 and 6 are ball seats, 7 is an O-ring, 1
Reference numeral 5 is a body, and 9 is a seat retainer. Forming a convex portion 13a having two parallel flat surfaces on the lower end of the stem 13,
This is fitted relatively tightly into the concave groove 12a provided in the upper portion of the ball 12, and further, as shown in the figure, the tubular member 14 screwed and fixed to the body 15 is fitted into the port 12b below the ball 12. The ball 12 is fixed on its axis of rotation.

Further, the ball valve 1 shown in FIG. 1 is also shown in FIG.
In the ball valve 11 shown in FIG. 2, the O-ring 7 is attached to the back surface of the ball seats 5 and 6.

The operation of the two embodiments shown in FIGS. 1 and 3 will be described below. In the embodiment of FIG. 1, for example, when the pressure at the pipe connecting end 8a is higher than the pressure at the other pipe connecting ends 8b and 8c, the ball 2 is pushed to the left in the figure by the difference in pressure, but the ball 2 Does not move because it is connected to the stem 3 by fitting and bolting and is fixed on its rotation axis.

In the embodiment of FIG. 3, for example, the pressure at the pipe connecting end 15a is different from the pressure at the other pipe connecting ends 15b and 15b.
When higher than the pressure at c, the ball 12 is pushed to the left of the figure by this pressure difference, but the ball 12
Is fixed on the axis of rotation by the stem 13 and the tubular member 14, and therefore does not move.

Therefore, between the ball 2 and the seat retainer 9 and the ball 1 on the side of the pipe connecting ends 8a and 15a.
2 and the seat retainer 9 are attached to the ball seat 5 without changing the pressure bonding state, and the pipe connecting end 8a or 15
There is no leakage from a into the body cavity 8d or 15d.

Further, even if the balls 2 and 12 are rotated so that the area for supporting the balls 2 or 12 of the ball seat 6 becomes smaller as shown in FIG. 7 for the conventional three-way ball valve, the balls 2 and 12 are Since 12 does not move,
The ball seat 6 is not compressed enough to cause local permanent deformation, and the sealing performance is not deteriorated.

Further, in the two-face sheet type three-way ball valves 1 and 11 which are the embodiments of the present invention, unlike the floating ball type, the balls 2 and 12 are formed by the fluid pressure.
Does not press the ball seats 6 on the downstream side, but since the O-rings 7 are attached to the back surfaces of the ball seats 5 and 6, the ball seats 5 and 6 on the upstream side are thereby mounted.
It completely prevents back leakage in the ball seats 5 and 6
Increase the elastic force to press the ball onto the ball 2 or 12,
The body cavity 8 in the ball seat 5 on the upstream side
A leak to d or 15d can be reliably sealed.

In the embodiment shown in FIG. 1, the stem 3
Is fitted to the ball 2 and the stem 3 is completely prevented from popping out by the pressure of the fluid inside,
Parts such as the stem retainer 16 provided to prevent the stem 13 from popping out in the embodiment of FIG. 3 are not necessary.

[0033]

As described above, the two-sided seat type three-way ball valve of the present invention does not cause internal leakage due to the pressure difference of the fluid even if it is the two-sided seat type, and is locally attached to the ball seat. There is no possibility of causing permanent deformation and deteriorating the sealing property. Further, there is no need for a component for preventing the stem from popping out, which is economical.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a two-sided sheet type three-way ball valve of the present invention.

2 is a partial cross-sectional view showing the ball and stem in FIG. 1 in a cross section including the center line of the stem perpendicular to the cross section in FIG.

FIG. 3 is a vertical cross-sectional view showing another embodiment of the two-face seat type three-way ball valve of the present invention.

FIG. 4 is a vertical cross-sectional view showing an example of a conventional two-side seat type three-way ball valve.

FIG. 5 is a vertical cross-sectional view of a two-way ball valve shown for explanation.

6 is a vertical cross-sectional view showing a closed state of the two-way ball valve shown in FIG.

7 is a transverse cross-sectional view showing a state in which the balls of the conventional two-sided seat type three-way ball valve shown in FIG. 4 are slightly rotated.

[Explanation of symbols]

 1, 11 Two-side seat type three-way ball valve 2, 12 Ball 3, 13 Stem 4 Bolt 7 O-ring 12a Lower port 14 Cylindrical member

Claims (3)

[Claims] 1. A two-sided seat type three-way ball valve characterized in that a ball accommodated in a body is fixed on a rotation axis. 2. A two-sided seat type three-way ball valve according to claim 1, wherein the ball is connected to the stem by fitting and bolting and is fixed on the axis of rotation thereof. 3. A vertical three-way structure in which the ball is fixed on the body by fitting the stem on the upper side and on the lower side by a tubular member fitted on the lower port of the ball. The two-sided seat type three-way ball valve according to claim 1, which is a ball valve.