JPS643877Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) The present invention relates to an elastic ball seat mounting structure for a ball valve, and in particular, the invention relates to an elastic ball seat mounting structure for a ball valve, and in particular, to prevent the elastic ball seat provided in the body of the valve from protruding toward the flow path side or from elasticity. This invention relates to an elastic ball seat mounting structure that prevents deformation and damage to the ball seat, reliably prevents leakage from the part where the elastic ball seat is mounted, and facilitates replacement of the elastic ball seat.

(Prior art) Generally, there are floating type and trunnion type ball valves, and both are equipped with an elastic ball seat that seals the valve by contacting the ball surface. Usually, an elastic ball seat is simply attached to a step provided on the body near the ball surface, or an elastic ball seat is inserted into a seat retainer provided within the body.

By the way, various mounting structures for ball seats have been proposed in the past, and one example will be explained using Japanese Patent Laid-Open No. 48-40026 as an example.

The bulletin states that the valve seat is pressed into contact with a retaining ring (insert) screwed into the body, and the contact surface between the retaining ring and the valve seat is shaped like a truncated cone to improve sealing performance and position the valve seat. What has been done is disclosed.

(Problem that the invention aims to solve) However, when using a ball valve, the elastic ball seat generally pops out from the body or seat retainer toward the flow path due to fluid pressure, abnormal pressure rise, temperature rise, etc. In many cases, the sealing function of the elastic ball sheet deteriorates significantly due to deformation or damage to the elastic ball sheet. Furthermore, if measures were taken to prevent this, it became difficult to replace the elastic ball seat.

Furthermore, according to the above-mentioned conventional publication, the valve seat is pressed by a retaining ring and is mounted in contact with the shoulder of the body. If the ball is pressed abnormally on the surface, if the ball is rotated in the opening direction in this state, a part of the annular valve seat will be exposed to the through hole side of the ball when the ball reaches the approximately 45 degree position. Since it would be difficult to return to its previous position if it were to pop out, there was a risk that major problems would occur, such as the sealing function of the valve seat being impaired.

Structure of the invention (Means for solving the problems) The present invention provides a new and useful ball valve that completely solves the problems of the conventional one. established,
In a ball valve in which an elastic ball seat is brought into sealing contact with the ball surface, and the elastic ball seat is attached to a step formed in the body or a groove of a seat retainer installed in the body, the above-mentioned step or groove is provided. In this method, a female screw part is provided in the fluid direction of the valve, and an engaging surface is formed at the deep part of the female screw part perpendicular to the screwing direction, and the outer peripheral surface of the elastic ball seat is By providing a male threaded portion and screwing the male threaded portion into the female threaded portion, the threaded end surface of the male threaded portion of the elastic ball sheet is pressed against the engagement surface of the step portion or groove. This is an elastic ball seat mounting structure for a ball valve in which both are brought into close contact with each other, and a locking portion for locking a tool is provided on the opposite surface of the screwing tip surface of the male screw portion.

(Function) To install the elastic ball seat of the present invention, a tool is locked in the locking part, and the tool is screwed into the step formed in the body or into the groove of the seat retainer installed in the body. Screw in until it is pressed against the engaging surface of the part or groove.

Then, the threaded end surface of the ball seat comes into close contact with the engagement surface, effectively exhibiting a sealing function, and preventing leakage from the bottom.

Furthermore, even if the ball is rotated in a state where the pressure inside the body is abnormally increased, the elastic ball seat is securely screwed into the step or groove.
It does not pop out or move unnecessarily, maintains the installed state reliably, and provides a sealing mechanism over a long period of time.

Furthermore, even when replacing the ball seat, it can be done extremely easily since it is only screwed together.

(Example) Examples of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a floating type ball valve, and FIG. 2 is a partially enlarged sectional view of FIG. 1.

In the figure, 1 is the ball valve body, 2 is the body 1
This ball 2 is rotatably provided inside the valve 2. A through hole 3 is formed in the ball 2, and the rotation of the ball 2 enables opening and closing of the valve.

Reference numeral 4 denotes a stepped portion formed in the body 1, and this stepped portion 4 has a female screw portion 5 formed on the inner peripheral surface in the fluid direction, and an engaging surface 4a perpendicular to the screwing direction at the deep part of the screwing. is formed. Reference numeral 6 denotes a pair of ball seats that are in sealing contact with the surface of the ball 2, and a male screw portion 7 is screwed into the outer peripheral surface of the elastic ball sheet 6. A tip surface 6a is formed at the tip end of the male screw portion 7. It is screwed into the female threaded portion 5 described above.

As described above, the elastic ball sheet 6 is securely screwed to the step portion 4, so that even if the elastic ball sheet 6 is deformed by abnormal pressure of the fluid, there is no risk of the elastic ball sheet 6 accidentally popping out into the flow path. Furthermore, even if an excessive force is applied to the tongue-shaped portion 8 formed on the elastic ball sheet 6 and the like, the elastic ball sheet 6 is not easily deformed because the outer peripheral surface of the elastic ball sheet 6 is screwed.
The elastic ball sheet 6 can easily return to its original shape, and when the elastic ball sheet 6 is attached to the step portion 4, the elastic ball sheet 6 can be easily attached and detached by simply engaging the engagement portion 10 such as a convex claw or a concave groove formed on the elastic ball sheet 6 with a tool and screwing the elastic ball sheet 6.
The tip surface 6a of the plug 6 is pressed against the engagement surface 4a of the step portion 4 to come into complete face-to-face contact, so that the two provide a strong seal and prevent leakage from the back side of the plug 6.

In addition, as shown in FIGS. 3 and 4, by providing a sealing member (for example, an O-ring, a gasket, etc.) 9, the above-mentioned leakage prevention can be further ensured.

Next, FIG. 5 is a longitudinal sectional view showing a trunnion type ball valve, and FIG. 6 is a partially enlarged sectional view of FIG. 5.

In the figure, 12 is the body of the ball valve, 13 is the ball rotated by the stem 14, and 15 is the ball 1.
This is a trunnion shaft in which the lower part of 3 is rotatably attached to the body 12. Reference numeral 16 denotes a seat retainer attached to the stepped portion 17 of the body 12, and this seat retainer 16 is pressed in the direction of the ball surface via a leaf spring 18.

19 is a female screw portion formed in the fluid direction on the outer peripheral side of the groove 24 formed in the seat retainer 16;
Reference numeral 4a denotes an engagement surface provided at the inner part of the screw-in part at right angles to the screw-in direction. A male threaded portion 21 formed on the outer peripheral surface of an elastic ball seat 20 is screwed onto the female threaded portion 19. Reference numeral 20a denotes a tip provided at the screw-in tip of the elastic ball seat 20, and is crimped onto the engagement surface 24a. 22 is an O-ring provided on the seat retainer 16, and 23 is a locking portion such as a groove or a protruding pawl for locking a tool when screwing the ball seat 20 into the seat retainer 16.

Even when the elastic ball seat 20 is provided in the seat retainer 16 as described above, the elastic ball seat 2
Since the elastic ball seat 20 can be screwed on, deformation and damage to the elastic ball seat 20 can be prevented. Also, the tip end surface 20a of the elastic ball seat 20 is connected to the seat retainer 1.
By press-fitting the engaging surface 24a of the groove 24 of No. 6, leakage from the back can be prevented. Furthermore, the elastic ball seat can be easily replaced.

Furthermore, the present invention can be applied to any of two-way, three-way, and four-way ball valves, and at least one of the two or more elastic seal members installed in these ball valves. This also includes the case where it is attached by screwing means.

Effects of the invention As stated above, the following effects can be obtained by the invention.

(1) During use, the elastic ball sheet does not protrude toward the flow path, is not deformed, or is damaged, and exhibits its sealing function effectively over a long period of time, providing excellent durability.

(2) It is possible to easily and reliably position the elastic ball seat when installing it and when replacing it.

(3) A sealing effect is achieved between the tip end surface of the elastic ball seat and the engagement surface of the mounting portion, and leakage from the back of the elastic ball seat can be reliably prevented.

(4) It is possible to provide a ball valve with a simple structure, excellent economic efficiency, and high reliability.

[Brief explanation of the drawing]

The drawings show each embodiment of the present invention, and FIG. 1 is a longitudinal sectional view showing an example of a floating type valve, FIG. 2 is a partially enlarged sectional view of the same, and FIGS. Fig. 4 is a partially cutaway sectional view showing another embodiment of the present invention, Fig. 5 is a longitudinal sectional view showing an example of a trunnion type valve, and Fig. 6 is a partially enlarged sectional view of the same. be. 1,12...Body, 2,13...Ball, 3
...Through hole, 4...Step, 24...Groove, 4a, 2
4a...Engaging surface, 5, 19...Female screw portion, 6, 2
0... Elastic ball seat, 6a, 20a... Tip surface, 7, 21... Male thread part, 10... Locking part, 1
6... Seat retainer.

Claims (1)

[Scope of utility model registration request] A ball having a through hole is rotatably provided in the body, an elastic ball seat is brought into sealing contact with the ball surface, and the elastic ball seat is installed in a step formed in the body or in a groove of a seat retainer installed in the body. In a ball valve designed to
The above-mentioned step or groove is provided with a female screw portion in the fluid direction of the valve, and an engagement surface located at a right angle to the screw direction is formed at the deep end of the female screw portion,
By providing a male threaded portion on the outer peripheral surface of the elastic ball sheet and screwing the male threaded portion into the female threaded portion, the threaded end surface of the male threaded portion of the elastic ball sheet is formed into the stepped portion or An elastic ball of a ball valve, characterized in that the elastic ball is crimped onto the engagement surface of the groove to bring them into close contact, and further includes a locking portion for locking a tool on the opposite surface of the threaded tip surface of the male screw portion. Seat attachment structure.