JPH09210225A - Synthetic resin-made ball valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix the dimension between valve unit holding parts in a valve casing receiving a ball valve unit and a seat ring, so as to provide uniform seal performance and operating force over a long period. SOLUTION: This ball valve is opened/closed by almost 90 deg. rotating a valve unit by operating a valve rod, a lower part of a ball valve unit 3 is rotatably supported to be received in a valve casing 1, the valve casing 1 and a cover 2 are thermally fused and integrally connected. The lower part of the ball valve unit 3 is rotatably supported and received in the valve casing 1, also in a relation between the ball valve unit 3 and a seat ring 5, the valve unit 3 is provided so as to seal by contact with the seat ring 5, the dimension between axial direction surfaces of a valve unit through hole is provided so as to generate a clearance between the seat ring 5 and the valve unit in its fully opened position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball valve made of a thermoplastic resin used for burying a gas transportation pipe for city gas, natural gas or the like.

[0002]

2. Description of the Related Art In recent years, a thermoplastic resin pipe such as a polyethylene resin has been increasingly used as a buried gas pipe. The joints and ball valves used for these pipes are also made of the same thermoplastic resin, and are electrically fused or thermally fused to the pipes to be connected. The above-mentioned buried ball valve usually has a ball valve body having a through hole that forms a flow path and a seat ring made of ethylene tetrafluoride resin or rubber that seals the valve body in the valve chamber. The seat rings are arranged so as to face each other on both sides of the ball valve body, and are held inside the valve chamber while the valve body retains the repulsive force. By rotating the valve body by 90 degrees, the valve box and the ball valve body are opened and closed with a sealing property. Since the ball valve element is mounted in the valve chamber through the seat ring, it slightly moves in the fluid flow direction. When the valve is closed, the pressure of the fluid is applied to the ball valve element and the ball valve element is pressed to the downstream side. Therefore, the ball valve element is firmly adhered to the seat ring on the downstream side to improve the sealing property. Such a ball valve is generally called a floating type ball valve.

If the ball valve is not opened and closed for a long time, the grease used is pushed out from the contact surface between the ball valve body and the seat ring and escapes, and the ball valve body and the seat ring are solidified by the grease. There was a case that the coefficient of friction became large, uniform torque could not be obtained, and opening and closing operations could not be performed smoothly in an emergency. Further, when left for a long period of time, the elastic force is lost due to the creep of the seat ring, and there is a problem that it is impossible to always maintain a good sealing property. Therefore, the ball valve disclosed in Japanese Utility Model Publication No. 4-35643 is also a floating type valve,
It has been proposed that the contact area between the seat ring and the ball valve element when fully opened is reduced by providing a relief surface on the seat ring to improve operability.

Further, in the ball valve disclosed in Japanese Utility Model Publication No. 4-39492, when the main body main body portion having one seat ring and the body cap having the other seat ring are heat-sealed, In order to keep the degree of insertion into the main body of the body constant, that is, to keep the holding dimension between both seat rings constant, an annular stopper is provided on the body cap to keep the degree of insertion constant, and seals on both sides of the valve body. The surface pressure is made uniform to obtain a stable sealing property.

[0005]

However, since the ball valves disclosed in Japanese Utility Model Publication No. 4-35643 and Japanese Utility Model Publication No. 4-39492 are both floating type ball valves described above, they are not fully closed. Fluid pressure is applied to the spherical valve body, and the valve body is strongly pressed against the downstream seat ring. To open it, it is rotated while being pushed to the downstream side by fluid pressure, so even when fully opened, the ball valve body is pressed strongly against the downstream side seat ring compared to the upstream side seat ring, and the valve body and seat ring A lot of contact area with will come into contact. As a result, a uniform surface pressure cannot be applied to the seat rings on both sides, the rotational torque of the valve element increases, and the seat ring creeps for a long period of time, and the sealing performance at the time of valve closing cannot be obtained. There is a problem.

In the ball valve of Japanese Utility Model Publication No. 4-39492, when the body cap is butt-welded to the valve box,
Although the size of the ball valve holding part due to the seat ring does not vary, the main body forming the valve box and the body cap are heat-sealed, and the seat ring and valve in the axial direction of the valve box The thermal fusion is performed in a direction that directly affects the holding size of the body. Therefore, even if there is a stopper, it is difficult to fuse the dimension in the axial direction of the valve box at regular intervals,
In addition, since the distance between the fusion part and the stopper part is close, the heat effect of the heating and fusion process affects the stopper part as well, and the stopper effect during fusion disappears. There is a problem in that the dimension between the body holding portions varies, and it is difficult to manufacture a ball valve having a dimension between the body holding portions that always has a stable sealing property.

Since the buried ball valve is usually buried in the soil, it is buried in the soil except for the central portion of the valve box body. For this reason, the pipe flow paths at both ends of the valve box cannot be discriminated from the ground, and in some cases, it cannot be discriminated from the ground as to which direction the buried pipe is installed. Therefore, even if the handle operating rod is inserted from the ground and the valve rod of the ball valve buried in the ground is rotated, the operating position as to whether the ball valve is closed or opened may not be known and an erroneous operation may be performed. Also, since the handle operating rod is inserted and opened from the ground to the buried ball valve, if the lower part of the valve has an unstable shape such as a cylindrical surface that easily rolls down, it is not possible to place it stably and the upper part of the valve cannot be placed. There is a problem that it is difficult to properly implement piping to the ground.

The present invention provides a synthetic resin ball valve which solves the above-mentioned problems, and makes the dimension between the valve body holding portions of the valve body accommodating the ball valve body and the seat ring constant for a long period of time. It has a uniform sealing property and operating force over a wide range, and a uniform valve assembly structure is obtained.Furthermore, even if it is buried in the soil, the flow direction of the valve box and the through hole direction of the ball valve body can be confirmed from the ground. The present invention provides a synthetic resin ball valve in which opening and closing operations of the valve can be performed without mistake, the valve box can be stably placed, and piping can be easily performed.

[0009]

DISCLOSURE OF THE INVENTION The gist of the present invention is to provide a ball valve body having a through hole in the axial direction, seat rings arranged on opposite sides of the ball valve body, and the seat ring and the ball valve body. A valve box made of a thermoplastic resin having an opening for accommodating the inside and inserting the valve body in the upper part, a lid made of a thermoplastic resin for covering the opening on the upper surface of the valve box, and a valve box attached to the lid. A ball valve that is engaged with a ball valve element inside the valve valve and that opens and closes by operating the valve rod to rotate the valve element by approximately 90 degrees, and the lower portion of the ball valve element is rotatable within the valve box. A ball valve made of synthetic resin, characterized in that the valve box and the lid are heat-fused and integrally joined together.

Further, according to the present invention, a ball valve body having a through hole in the axial direction, seat rings arranged on both sides of the ball valve body so as to face each other, and the seat ring and the ball valve body are housed inside and the upper part is provided. A valve box made of a thermoplastic resin having an opening for inserting the valve body, a lid made of a thermoplastic resin for covering the opening on the upper surface of the valve box, and a ball valve inside the valve box attached to the lid. It is composed of a mating valve rod, and the valve body is operated by operating the valve rod approximately 9
In a ball valve that opens and closes when rotated by 0 degrees, the lower portion of the ball valve element is rotatably supported and accommodated in a valve box, and the relationship between the ball valve element and the seat ring is determined by the closing position of the valve element. Is provided so as to abut and seal the seat ring, and the axial face-to-face dimension of the valve body through hole is provided so that a gap is created between the seat ring and the seat ring at the fully opened position. This is a resin ball valve.

It is desirable that the lid and the valve box be provided with a stopper portion at a position apart from the heat-sealed portion so as to make a butt margin of the welding constant. Further, in the ball valve, an identifying portion is provided on the upper surface of the lid so that the pipe axial direction of the valve box can be seen from above, and the through hole direction of the spherical valve body can be seen from above at the upper end of the valve rod. It is desirable to provide a resin cap. Further, it is preferable that a plurality of protruding ribs extending downward from the lower surface of the central portion of the valve box are provided on the lower surface of the valve box so that the valve box can be mounted without rolling.

[0012]

The present invention is not a conventional floating type ball valve, but the lower part of the ball valve body is rotatably supported on the inner surface of the valve box, and the valve box members are not heat-sealed.
Since the valve box accommodating the valve body and the seat ring is formed of an integral member, the valve chamber accommodating the seat ring and the ball valve body is always kept at a constant size. In addition, the valve body and seat ring are inserted through the opening in the upper part of the valve box to support the lower part of the valve body on the inner surface of the valve box. The ball valve element is rotated about the axis, and the contact surface pressure with the left and right seat rings is also equalized. In this state, the lid is heat-sealed to the opening in the upper part of the valve box.Therefore, regarding the inner dimensions of the valve chamber where the valve body and seat ring are mounted, the It is possible to obtain a valve that does not influence the influence or the dimension between the sealing surfaces on the ball valve body in the valve chamber and always maintains the uniform sealing surface pressure with the valve body.

Further, with respect to the seal surface pressure holding dimension of the seat ring (this refers to the dimension between the valve body and the seat ring where good sealing performance is achieved when the seat ring contacts the valve body), when fully closed. A face-to-face dimension in the axial direction of the through hole of the ball valve element is provided so that the seat ring is sealed with an appropriate sealing surface pressure and does not come into contact with the seat ring when fully opened. Therefore, in the case of a ball valve which is used in a fully opened state for a long time, the seat ring does not contact the valve body, so that the seat ring does not creep and the elasticity is not lost. In addition, the valve body closing operation is light at the time of emergency, and the sealing property of the seat ring when closing is good. This is because the valve body insertion opening is provided in the upper part of the valve box so that the assembly dimension between the two seat rings is constant, and the lower part of the valve body is rotatably supported in the valve box. The fact that they were housed also contributed greatly.

Further, the fusion of the valve box and the lid is provided with a stopper portion at a portion distant from the fusion portion so as to keep the butt margin of the fusion constant, so that the stopper is softened and the dimensions are varied. Without a stopper, a uniform fusion allowance can be obtained. In addition, an identification section is provided on the upper surface of the fusion-bonded lid on the top of the valve box so that the flow path of the valve box can be identified, and a cap is provided on the top of the valve rod so that the direction of the ball valve through hole can be identified. Even if the valve box is buried and the pipe axis directions at both ends of the valve box are not known, the opening and closing operation of the valve can be surely performed without fail by looking at the identification part on the lid upper surface and the cap on the valve rod upper part from the ground. Furthermore, since there are multiple protruding ribs on the bottom surface of the valve box that allow the valve box to be placed without rolling, the valve box can be placed stably, and therefore horizontal and vertical centering is easy and piping is not required. It is easy and easy to handle as a single unit before piping.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of a ball valve showing a first embodiment. 1 is a polyethylene resin valve box, and a valve chamber 1 for accommodating a ball valve body 3 and a seat ring 5.
a, the flow path 1b and the connecting portion 1c with the pipe are symmetrically provided,
It has an opening 1e at the top and is integrally molded by injection molding. Reference numeral 2 denotes a lid, and a fitting hole 2a into which the valve rod 4 is fitted is provided at the center, and the lid 2 is also made of the same polyethylene resin and is fusion-fixed to the valve box 1 by butt fusion. The lid 2 may have a round shape or an oval shape, but the oval shape has an advantage that a small amount of material is required for molding. Further, the lid 2 is provided with a guide portion 2b in order to make the fitting hole 2a of the lid 2 and the concentricity of the valve rod 4 and the ball valve body 3 in fusion welding the butt to the valve box 3.

A ball valve element 3 is incorporated in the valve chamber 1a of the valve box 1. The valve body 3 has a through hole channel 3a inside,
In addition, the trunnion stub 3b is provided at the bottom of the valve box 1
A stub fitting hole 1d is provided in the lower portion of the valve chamber 1a. The trunnion stub 3b and the stub fitting hole 1d are fitted to each other, and the ball valve element 3 is rotatably supported in the valve box 1 about this shaft. Therefore, the valve body 3 is not moved in the flow direction by the fluid pressure. The trunnion stub 3b may be provided integrally with the valve body 3 as shown in FIG. 1, or may be rotatably supported in the valve box 1 as another component.

A fitting portion 3c for fitting with the valve rod 4 is provided on the upper portion of the ball valve body 3. In the valve chamber 1a, the seat rings 5 for maintaining the hermeticity when fully closed are installed at both ends of the valve body 3 at positions equally distributed to the left and right with respect to the rotation axes of the spherical valve body 3 and the valve rod 4. There is. The drawing shows the valve body when fully opened. In this state, the surface of the valve body flow passage 3a is made larger than the seal surface pressure holding dimension at the valve body closed position so that a gap is formed between the seat ring 5 and the valve body 3. The space size is small. Specifically, it may be chamfered in the vertical direction so as to take an angle at the intersection with the outer surface of the valve body 3. Therefore, since the seat ring 5 has a uniform gap left and right with the valve body 3 when the valve is fully opened, no contact pressure is applied to the seat ring 5 and also from the opening 1e in the upper part of the valve box. The valve body 3 can be easily attached. Then, by rotating the valve rod 4 fitted in the valve body 3 by 90 °, the valve is fully closed or fully opened. Therefore, the torque for rotating from the fully open position to the fully closed side can be light.

The valve rod 4 is made of stainless steel and has an O-ring seal with the lid 2 and a 90 degree opening / closing stopper pin 15 is fitted on the upper portion thereof, and a cap 6 is mounted on the upper portion thereof. Cap 6
Is rotatably fitted to the lid 2 by O-ring sealing. The lid 1 and the inner peripheral side guide portion 2b are fitted into the opening 1e in the upper part of the valve box, and the outer peripheral side 7 is provided with a space between the cover 2 and the guide portion 2b.
The butt is fused. In the fully opened state of the valve of FIGS. 1 and 2, the ball valve body 3 and the seat ring 5 have a certain clearance, and the ball valve body is mounted while being supported by the center of rotation of the inner surface of the valve box. The valve body can be rotated with a small operating force without creeping to the ring. Further, even in the stage of rotating the valve body, since the ball valve body 3 has a structure in which the rotation axis is determined around the center of the valve box, it is not affected by fluid pressure and seat rings provided on both sides of the spherical valve body 3 are not affected. 5 is rotated while applying a uniform surface pressure. For this reason, the valve body and the seat ring are not strongly pressed or stuck, and the operating force for opening and closing the valve body does not suddenly change.
Smooth operation is possible, and the seat ring and a constant sealing surface pressure are always maintained and good sealing performance is obtained.

FIG. 2 is an enlarged sectional view of the upper portion and the lid portion of the valve box. The fitting guide portion 2b of the lid 2 is provided to keep the amount of butt fusion of the valve box 1 and the lid 2 in butt fusion.
By providing a stopper 2c on the end face portion of the valve and providing a fusion portion 7 on the outer peripheral side with a space from the guide portion 2b, the stopper 2c abuts on the guide bottom portion 1f of the valve box 1 when the fusion welding portion 7 is welded by the butt. Then, the amount of the abutting fusion of the fusion bonding portion 7 is made constant. With this structure, even when the fusion-bonded portion 7 of the valve box 1 and the lid 2 is heated and melted, the stopper portion 2c does not melt.
Since they are farther apart, the butt fusion amount of the fusion-bonding portion 7 can be reliably made constant without being affected by the heat of the fusion-bonding portion 7. The guide portion 2 and the stopper portion 2c may be provided in the valve box and the lid so as to have a reverse concavo-convex relationship.

FIG. 3 is a vertical sectional view of the periphery of the lid according to the second embodiment of the present invention. In this embodiment, after the piped valve body is buried in the soil, a protective pipe 9 is attached to the upper surface of the lid so that the valve can be opened and closed from the ground. Ribs 8 are provided on the upper surface of the lid 2 so as to radially project from the center of rotation of the valve rod 4 to the outer periphery of the lid 2 so that the outer periphery of the rib 8 can be used as a guide to easily attach the protective tube 9. As a result, it is possible to open and close the valve by inserting the handle operating rod from the ground without burying the operation part of the valve piped in the ground with earth and sand.

FIG. 4 is a plan view of FIG. 3, in which the ribs 8 projecting upward are spaced apart in the circumferential direction of the ribs 8 so that the flow direction of the valve box 1 can be seen from above the valve. As shown in the figure, the ribs 8a in the flow path direction are narrowly provided so as to form a pair, and even if the rib 8a indicating the axial direction of the valve box is buried in the connection port 11 of the valve box and cannot be seen from the ground. The rib piping direction can be determined by looking at the rib 8a. Further, the cap 6 which covers the upper end of the valve rod 4 is also provided with a recessed line 12 indicating the through flow direction of the ball valve body so that the direction of the flow path 3a of the valve body 3 can be seen from above. It is painted in fluorescent color for easy viewing. As a result, even if the valve body is buried in the ground, the open / closed state of the valve can be discriminated by looking through the operation portion of the valve in the protection pipe 9 from the ground, and a reliable opening / closing operation can be performed. . The line 12 of the cap 6 may be provided as a convex portion, or instead of the line 12, the entire shape of the cap may be provided as a rhombus shape that is long and thin in the flow path direction.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, the ball valve element 3 and the valve rod 4 are integrally formed, and the trunnion stub is also integrally formed. Regarding integral molding with the valve rod or stub, either integral molding with the same material or insert molding with a valve rod or stub of another material may be performed. In addition, the same polyethylene connecting pipe 10 is previously inserted into the connecting ports 11 at both ends of the valve box and the sockets are fused and provided. Therefore, this connecting pipe 1
It is convenient because the polyethylene pipe and the electric fusion joint can be used at the burying site by using No. 0, or the butt fusion can be performed and the pipe can be immediately connected. Also in the present invention, the same effect as the first embodiment can be obtained.

As shown in FIGS. 1 and 5, projecting ribs 13, 13 are provided on both sides of the lower surface of the valve box 1 to prevent the valve box from rotating and rolling on a flat surface. It can be placed. The projecting ribs 13 may be provided at four places on the lower surface of the valve box 1, or the projecting ribs 13 having an installation width where the valve box 1 does not roll may be provided at two places on both sides. The protruding ribs 13 are placed below the lower surface 14 of the central portion of the valve box, and the remains of the dam when the valve body 1 is provided by resin injection molding remain on the lower surface 14 of the central portion. Even
The projecting ribs 13, 13 enable stable mounting.

[0024]

The synthetic resin ball valve of the present invention is mounted on both sides of the valve body such that the ball valve body does not move under the influence of fluid pressure and is always held in the center of the valve box for rotation. The seat ring always maintains a fixed positional relationship, and the surface pressure applied to the seat ring when fully opened is smaller than that when fully closed. Therefore, uniform sealability and operability are obtained, creep is unlikely to occur in the seat ring, the elastic force of the seat ring is retained, and a long life is maintained. Furthermore, the surface pressure holding dimension of the seat ring does not change depending on the assembly method, and the sealing performance does not change. Therefore, good sealing performance can be maintained over a long period of time, the valve can be opened and closed easily, and the valve can be opened and closed without fail even when the pipe is buried. Since it can be placed, it is easy to handle and easy to handle.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view around fusion of the valve box and the lid of FIG.

FIG. 3 is a vertical cross-sectional view around a lid according to a second embodiment of the present invention.

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is a sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

1 ... Valve box 1a ... Valve chamber 1
f ... Valve box guide bottom 2 ... Lid 2b ... Lid guide 2
c ... Lid stopper 3 ... Ball valve body 3b ... Trunnion stub 4
… Valve 5… Seat ring 6… Cap 7
… Fusion part 8… Rib 9… Protection tube 1
0 ... Connection pipe 11 ... Valve box connection port 12 ... Line showing flow direction 1
3 ... protruding rib

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasushi Kondo 200 Komukai, Asahi-cho, Mie-gun, Mie Prefecture Hitachi Valve Co., Ltd.

Claims (5)

[Claims] 1. A ball valve body having a through hole in an axial direction, seat rings arranged on both sides of the ball valve body so as to face each other, a seat body and a ball valve body housed inside, and a valve body is provided at an upper portion. A valve box made of a thermoplastic resin having an opening for insertion, a lid made of a thermoplastic resin covering the opening on the upper surface of the valve box, and a valve mounted on the lid to engage a ball valve element in the valve box. A ball valve, which comprises a rod and is opened and closed by operating the valve rod to rotate the valve body by about 90 degrees, wherein the lower portion of the ball valve body is rotatably supported and accommodated in the valve box, and A synthetic resin ball valve in which a lid is heat-sealed and integrally joined. 2. A ball valve body having a through hole in the axial direction, seat rings arranged on both sides of the ball valve body so as to face each other, and the seat ring and the ball valve body are housed inside and the valve body is mounted on the upper part. A valve box made of a thermoplastic resin having an opening for insertion, a lid made of a thermoplastic resin covering the opening on the upper surface of the valve box, and a valve mounted on the lid to engage a ball valve element in the valve box. A ball valve which comprises a rod and which opens and closes by operating the valve rod to rotate the valve body by about 90 degrees, wherein a lower portion of the ball valve body is rotatably supported and accommodated in a valve box, and the ball is The valve body and the seat ring are provided so as to abut and seal the seat ring at the closed position of the valve body, and at the fully opened position of the valve body, a gap is formed between the seat ring and the valve body through hole. Is characterized by the provision of the axial face-to-face dimension of Plastic ball valve. 3. The synthetic method according to claim 1, wherein the lid and the valve box are provided with a stopper portion at a position apart from the heat-sealing portion so as to make a butt margin of the welding constant. Resin ball valve. 4. A resin which is provided on an upper surface of the lid so as to identify an axial direction of the pipe of the valve box from above, and an upper end of the valve rod allows the direction of the through hole of the spherical valve body to be seen from above. The synthetic resin ball valve according to claim 1, wherein a cap made of synthetic resin is provided. 5. The lower surface of the valve box is provided with a plurality of projecting ribs extending downward from the lower surface of the central portion of the valve box, so that the valve box can be mounted without rolling. 4. The synthetic resin ball valve according to 4.