JPS636532Y2 - - Google Patents

Description

[Detailed Description of the Invention] The purpose of the present invention is to prevent the protrusion of the ball of a plastic ball valve in the closed state and to absorb excessive stress during use after piping.

The applicant had previously applied for Utility Model Application No. 100790 (1981) (Kokoku Publication No. 53-9951) regarding plastic ball valves and obtained a utility model right (Registration No.
1267355). However, with this ball valve, the union is only inserted into the valve body and is not directly engaged with the valve body, so when the cap nut is removed with the valve closed,
The structure is such that the ball and union are pushed out of the valve body by the pressure of the fluid. Therefore, when installing or replacing the pipe that connects to the fluid outflow side of the ball valve, replacing the seat pressed against the ball, or inspecting the ball surface,
It was found that there is a possibility that the ball or the ball and union protrude outside the valve body, which poses a safety problem.

One possible method to prevent the ball from protruding due to fluid pressure is to push a union with claws into the valve body, rotate it, and engage it directly with the groove in the valve body, but the structure using this method is disclosed in Japanese Patent No. 927630. (Japanese Patent Publication No. 53-6375). Other methods include gluing and fixing the ball to the stem, and bonding the union to the valve body.
These methods make it impossible to replace the ball or seat, and if a failure occurs, the entire valve must be replaced, which is uneconomical.

For the above-mentioned reasons, the present invention combines the unions 3 disposed on both sides of the ball with the valve body 1 by means of a screw having a gap 14 for screwing the unions 3 loosely in the axial direction. No.No.
No. 1267355). This prevents the ball 2 from protruding outside the valve body due to fluid pressure.

In addition, British Patent No. 974911 is known as a device which is apparently quite similar to the present invention, and attention is particularly drawn to the gasket 76 etc. seen in FIGS. 3 and 4.

However, in the proposed valve, the union 3
This valve differs from the prior art in that it is configured to flexibly resist pulling and bending moments applied to the pipe by providing a gap 14 between the valve body 1 and the valve body 1. This point will be explained in detail later with reference to FIG. 4.

A preferred embodiment of the present invention will be explained in detail below through the drawings. Figure 1 shows a ball valve (Utility Model Registration No. 1267355);
The figure shows a ball valve according to the invention. 1 is a valve body, 2 is a ball, and 3 is a union having a flange 13 that contacts the ball 2 and is connected to the body cap 4 via an O-ring 9. 4 is a body cap, 5 is a cap nut, 6 is a seat, 7 is a handle, 8 is a stem, 9 is an O-ring that seals between the union 3 and the body cap 4, and 10 is an O-ring that seals between the main body 1 and the union 3. ring,
11 is an O-ring that seals between the valve body 1 and the stem 8; 12 is a rubber sheet gasket inserted between the valve body 1 and the union 3; and 13 is a collar provided on the union 3. The union 3 is connected to the body cap via an O-ring 9 by screwing in a cap nut 5, and its position relative to the valve body 1 is fixed via a seat packing 12. The valve body 1 and the union 3 are screwed together and sealed by an O-ring 10.

As shown in Fig. 3, the threaded part of the valve body 1 and the union 3 is connected to the flange part 13 of the union 3.
Provided between the groove in which the ring 10 is fitted,
In addition, a gap 14 is provided between the valve body 1 and the screw thread of the valve body 1, so that the valve body 1 is loosely engaged with the valve body 1. In addition, since the sheet gasket 12 is interposed between the flange 13 of the union 3 and the main body 1, the union 3 can be tightened further, and the stress transmitted from the piping is greatly reduced by the sheet gasket 12 and the gap 14. effectively absorbed. Although the valve body 1 and the union 3 are screwed together,
Since the gap 14 is provided between both threads, the position of the union 3 relative to the valve body 1 is fixed via the seat packing 12 by screwing in the cap nut 5 as described above.

Since the union 3 is screwed onto the valve body 1, even if the cap nut 5 is removed while the ball valve is closed, the ball 2 is held down by the union 3 and is prevented from protruding outside the valve body 1 due to fluid pressure. be done. Furthermore, since the two unions 3 are equidistant from the center point of the valve body 1, it is extremely easy to assemble the ball 2 at the center of the valve body 1. Further, the stress due to thermal expansion of the pipe is dispersed from the collar 13 of the union 3 to the valve body 1 via the seat packing 12, so the stress applied to the ball 2 is reduced and an increase in handle torque is suppressed. In addition, since the union 3 is screwed into the valve body 1 and has a flange 13, it is not fixed at an angle with respect to the valve body 1, and an increase in handle torque due to the inclination fixation is prevented. .

In addition, in this invention, regarding the effect of loosely connecting the union and the valve body with a gap,
Since you may have some doubts, I would like to explain this in detail with reference to FIG.

FIG. 4 is a vertical cross-sectional view schematically showing the state of the threaded connection between the union and the valve body when the union 3 is screwed into the valve body 1. The upper side is the valve body 1, and the lower side is the union. 3 is shown.
Also, the left side of the figure is the ball side.

When the union 3 is screwed into the valve body 1 and fixed, the repulsive force of the ball and the seat (not shown in this figure) presses the threads of the union 3 against the wall of the threads of the valve body 1 opposite the ball.

After screwing in union 3, when tightening the cap nut (not shown in this figure) together with the body cap (not shown in this figure) to the valve body 1, the union 3 will be on the ball side as shown by the arrow. is pushed to state a or state b.

shows the state when the valve is closed. When fluid is passed through the valve and the valve is closed, the pressure of the fluid pushes the ball, so the ball is pushed as shown by the arrow. As shown, an acting force is generated from the left to the right in the figure, and the union 3 moves slightly from a to a' or from b to b'.

As can be seen from the above explanation, the gap in question is to alleviate the stress applied from the ball and the stress coming from the piping, weaken the force applied to the threads of the union 3 and the valve body 1, and also reduce the surface pressure between the seat and the ball. It also has the function of increasing tightening to control the

The sealing effect of the seat against the ball is as follows:
Since it is controlled by tightening the cap nut, even if there is a gap, the surface pressure between the ball and seat is maintained and the sealing action is not affected. Such a structure and effect cannot be achieved in the valve described in GB 974,911, which describes the prior art, and is neither expressed nor implied.

As described above, the present invention inherits most of the advantages of the previously registered ball valve, and eliminates its disadvantages by screwing the union into the valve body.

[Brief explanation of drawings]

Figure 1 is a vertical side view of a conventional ball valve, Figure 2 is a vertical side view of the ball valve of the present invention, and Figure 3 is a vertical side view of a conventional ball valve.
The figure is an enlarged longitudinal cross-sectional side view of the threaded portion. FIG. 4 is a schematic and partially enlarged detailed vertical cross-sectional view showing that the manner in which a gap is created at the threaded connection point between the union and the valve body during valve assembly and valve closing operation is variable. 1...Valve body, 2...Ball, 3...Union, 4...Body cap, 5...Cap nut, 6...Seat, 7...Handle, 9,1
0, 11... O-ring, 12... Seat packing, 13... Tsuba, 14... Gap.

Claims (1)

[Scope of utility model registration request] A valve body 1 having a valve chamber inside and having a male threaded portion on the outer periphery and a female threaded portion on the inner periphery at each of both ends.
, a ball 2 as a hollow valve member disposed in the valve chamber, a union 3 screwed into the female thread on the inner periphery of the end of the valve body 1, and A body cap 4 is crimped onto the outer end, a cap nut 5 is screwed onto a male thread on the outer periphery of the end of the valve body 1 to fix the body cap 4 in a predetermined position, and a cap nut 5 is interposed between the ball 2 and the union 3. In the plastic ball valve, the main components are a seat 6 with a seat 6 and a handle 7 for rotatably operating the ball 2 from outside the valve body 1 via a stem 8, which is arranged on both sides of the ball 2. The above-mentioned union 3 is connected to the ball 2 and connected to the body cap 4.
A flange portion 13 is provided in the valve body 1 and an elastic sheet packing 12 is inserted between the valve body 1 and the union 3, and the female threaded portion of the inner end of the valve body 1 and the male threaded portion of the union 3 are connected to each other with an axis between them. A ball valve characterized in that the ball valve is loosely screwed together by providing a gap 14 for loosely screwed connection in the direction.