JP2000240823A - Ball shaped valve element support structure for ball valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball-shaped valve element support structure for a ball valve, which is simple in structure and inexpensive due to a reduced number of parts, facilitates work and assembly, and can extend a seal life through an even abutting of a seat. SOLUTION: A thread hole 10 concentric with a rotational axis (a) of a ball-shaped valve element 5 held rotatably within a valve case 2 for opening and closing a valve casing passage 3 is formed in a lower portion thereof. A ball stay 12, the lower portion of which abuts on the inner circumferential flat surface of the valve case 2 is fitted into the thread hole 10. A set screw 13 is screwed into the thread hole 10, so as to align an axis of the valve casing passage 3 with the axis of the ball-shaped valve element 5 by adjusting a screwing amount of the set screw 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball valve support structure for a ball valve which is used by being interposed in various fluid transport pipes.

[0002]

2. Description of the Related Art A ball valve of this type generally has a basic structure as shown in FIG. In other words, the valve housing 2 has flanges 1 and 1 for connection to the pipeline at both ends, and the valve housing 2 is formed by fixing and joining the divided valve housings 2A and 2B which are divided into right and left. A valve stem 4 having a vertical axis a perpendicular to the flow direction of the fluid in 3 is rotatably supported, and the rotation of the valve stem 4 around the vertical axis a causes the flow path 3 in the valve box to rotate. A ball valve element 5 that opens and closes is held in the valve box 2. A spherical sheet 5 a is formed on the outer peripheral surface of the ball-shaped valve element 5, and an annular sheet 6 slidably in contact with the spherical sheet 5 a is located immediately upstream and downstream of the valve element 5 in the valve box 2. Is attached to each.

In the ball valve having the above-described structure, the axis of the flow path 3 in the valve box and the axis of the ball-shaped valve element 5 are vertically displaced by the weight of the ball-shaped valve element 5 so that the valve-element-side spherical seat 5 a The contact with the valve box side sheet 6 becomes uneven, and as a result,
There is a problem that the two sheets 5a and 6 are unevenly worn and the sealing performance deteriorates in a short period of time. In order to suppress a reduction in the life of the seal due to such misalignment, it is necessary to support the ball-shaped valve element 5 at the lower portion thereof on the valve box 2 side. As a support structure A of the ball-shaped valve element 5 (a portion surrounded by a circle in FIG. 4), a configuration shown in FIG. 5 has conventionally been adopted. That is, a through hole 20 communicating with the outside is formed in a lower portion of the valve box 2 (one of the divided valve box portions 2B), and a ball stay is formed in the through hole 20 so that an upper end thereof contacts the outer peripheral surface of the ball valve element 5. (Ball support member) 21
And a sealing O-ring 22, a spring 23 and an O-ring 24 are fitted into the through-hole 20 below the ball stay 21, and a cover 25 for closing the lower end opening of the through-hole 20 is bolted through a bolt 26. By fixing the ball-shaped valve element 5 to the valve box 2 via the ball stay 21, the O-rings 22 and 24, and the spring 23, the axis of the ball-shaped valve element 5 coincides with the axis of the flow path 3 in the valve box. As described above.

[0004]

As described above, in the conventional ball valve body support structure of the ball valve, since the through hole 20 is formed in the lower portion of the valve box 2, the cover 25 for receiving the ball stay 21 and the cover 25 are provided. Parts such as the O-rings 22 and 24 for preventing fluid leakage are required, which complicates the structure and tends to increase the cost required for supporting the valve body. In order to accurately match the axis of the valve box flow path 3 with the axis of the ball-shaped valve element 5, the height of the inner surface protrusion of the cover 25 is processed according to the actual product, or the height is adjusted. There was a problem that processing and assembly became troublesome, such as using shims.

The present invention has been made to solve the above-mentioned problem, and has a small number of parts, is simple and inexpensive, and is easy to process and assemble. An object of the present invention is to provide a ball-shaped valve body support structure for a ball valve that can be achieved.

[0006]

In order to solve the above-mentioned problems, a ball-shaped valve body supporting structure for a ball valve according to the present invention according to the first aspect of the present invention comprises: By providing a ball-shaped valve element that opens and closes a flow path in the valve box by rotation about an axis along a direction crossing the flow, and mounting a valve-box-side sheet that slides on a spherical seat surface of the ball-shaped valve element. In the ball valve, a screw hole is formed in a lower part of the ball-shaped valve body concentrically with the rotation axis of the valve body, and a valve body support member having a lower end portion in contact with the inner peripheral surface of the valve box in the screw hole. And a set screw for adjusting the upper and lower cores of the flow path in the valve box and the ball-shaped valve body is screwed into a screw hole above the valve body support member, and the set screw is fixed to the valve body. It is characterized by having.

According to the present invention having the above-described structure, the ball-shaped valve element is inserted into the screw hole formed on the ball-shaped valve element and can be vertically adjusted and fixed by a set screw. The conventional support, in which the valve body support member is fitted and held in a through hole formed in the lower part of the valve box because the weight of the valve body is supported so that its axis matches the axis of the flow path in the valve box. Compared with the structure, the use of a cover for receiving the support member and the use of an O-ring for preventing fluid leakage can be omitted, the number of parts can be reduced, the structure can be simplified, and the cost can be reduced. In addition, it is possible to accurately match the upper and lower cores of the ball-shaped valve body with the flow path in the valve box simply by adjusting the screwing amount of the set screw, which makes machining and assembly easier than the conventional support structure. However, the life of the seal can be extended by evenly contacting the sheets.

In particular, by providing an elastic body between the valve body support member and the set screw, the lower end portion of the valve body support member is brought into elastic contact with the inner peripheral surface of the valve box, and foreign matter is interposed between the two. And the like can be prevented from being bitten, and the opening and closing operation of the valve body can be always kept in a smooth state.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical side view of a ball valve according to the present invention, and FIG. 2 is an enlarged vertical side view of a main part of the ball valve. Since the basic configuration of this ball valve is the same as that shown in FIG. 4, the same portions are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the ball valve having the above-described basic configuration, the configuration shown in FIG. 2 is adopted as the support structure A for the ball-shaped valve element 5. That is, a screw hole 10 concentric with the rotation axis a of the valve body 5 is formed below the ball-shaped valve body 5.
Is formed, and a horizontal flat surface 11 slightly protruding radially inward is formed on the inner peripheral surface of the valve box 2 (one of the divided valve box portions 2A) corresponding to the screw holes 10. .

After assembling the ball-shaped valve element 5 into the valve box 2,
A ball stay (valve body support member) 12 is fitted into the screw hole 10, and a set screw 13 with a hexagonal hole is screwed and set thereon, and the amount of screwing of the set screw 13 is adjusted to adjust the ball stay 12. The lower end of the valve body abuts against the flat surface 11 on the inner circumference of the valve box 2, and the axial force of the ball-shaped valve element 5 is made to coincide with the axis of the flow path 3 in the valve box by the reaction force thereof to perform the alignment. When the alignment is completed, the head of the set screw 13 is swaged or the head is spot-welded to fix the set screw 13 to the ball-shaped valve element 5. Further, an epoxy putty 14 is filled into the screw hole 10 remaining above the set screw 13 and hardened, so that the inner cylindrical surface 5b of the ball-shaped valve element 5 is finished to be flush.

In the ball valve having the support structure A as described above, the weight of the ball-shaped valve element 5 is received and supported on the flat surface 11 on the inner periphery of the valve box 2 by the set screw 13 and the ball stay 12, and both shafts are supported. Since the cores are aligned, the contact between the valve body-side sheet 5a and the valve box-side sheet 6 becomes uniform, and a reduction in sealing performance due to uneven wear of these sheets 5a and 6 can be suppressed.

Further, since there is no through hole in the lower portion of the valve box 2, there is little possibility of fluid leakage without using a cover or a special seal ring for closing the through hole, and a ball valve having a long seal life is used. The structure can be simple and inexpensive with a small number of parts. FIG. 3 is an enlarged vertical sectional side view of a main part of a ball valve according to another embodiment of the present invention. In this embodiment, in the above-described support structure A of the ball-shaped valve element 5, the ball stay 12 and the set screw 13 A spring 15 as an elastic body is interposed therebetween. In this case, the lower end portion of the ball stay 12 can be reliably brought into contact with and held by the flat surface 11 on the valve box 2 side by the elastic force of the spring 15. It is possible to prevent the ball-shaped valve element 5 from being bitten and keep the rotation opening and closing operation of the ball-shaped valve element 5 in a smooth state at all times.

[0014]

As described above, according to the present invention, the self-weight of the ball-shaped valve body is supported on the valve box by the valve body support member and the set screw inserted into the screw hole formed on the ball-shaped valve body side. Therefore, the axes of the valve body and the flow path in the valve box can be surely matched, and the contact of the seat can be made uniform, and the life of the seal can be extended. Moreover, since it is not necessary to form a through hole on the valve box side, it is not necessary to use a special seal or cover for preventing fluid leakage, and the number of parts can be reduced and the structure can be simplified. In addition, since there is no need to use actual shimming or adjustment shims for centering, machining and assembly are very easy, and the cost of the entire valve can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a vertical side view of a ball valve according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional side view of a main part of the ball valve.

FIG. 3 is an enlarged vertical sectional side view of a main part of a ball valve according to another embodiment of the present invention.

FIG. 4 is a longitudinal side view of a conventional general ball valve.

FIG. 5 is an enlarged longitudinal sectional side view of a main part of the conventional ball valve.

[Explanation of symbols]

 2 valve box 3 valve box flow path 5 ball-shaped valve element 5a valve element side seat 6 valve box side sheet 10 screw hole 11 flat surface on valve box side 12 ball stay (valve element support member) 13 set screw 15 spring (elastic body) )

Claims (2)

[Claims] 1. A ball-shaped valve element which opens and closes a flow path in a valve box by rotation about an axis along a direction crossing a flow of fluid in the flow path in the valve box, and the ball is provided in the valve box. In a ball valve having a valve box-side seat that is in sliding contact with the spherical seat surface of a spherical valve body, a screw hole is formed below the ball-shaped valve body concentrically with the rotation axis of the valve body. The valve body support member whose lower end is in contact with the inner peripheral surface of the valve box is fitted into the screw hole, and the screw holes above this valve body support member can adjust the flow path in the valve box and the upper and lower cores of the ball-shaped valve body. Wherein said set screw is screwed in and said set screw is fixed to the valve body. 2. The ball-shaped valve element supporting structure for a ball valve according to claim 1, wherein an elastic body is interposed between the valve element supporting member and the set screw.