JP2006220268A - Ball valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball valve suppressing co-rotation of a ball presser when removing a union nut, capable of removing a flanged short pipe, and preventing flying out of a ball. <P>SOLUTION: In the ball valve, the flanged short pipe 4 is arranged in an outer end of the ball presser 3 in an abutting state by turnably arranging a ball valve element 2 opening and closing a passage in a valve body 1, providing a seat 13 such that it is pressed against the ball valve element 2 by the ball presser 3, engaging a cap nut 5 with a flange part 16 of the flanged short pipe 4, and screwing the cap nut 5 on an end of the valve body 1. The ball presser 3 is screwed to at least one end inner circumference of the valve body 1, and a sliding member 19 of a material with a smaller coefficient of static friction than a material of the flanged short pipe 4 or a material of the cap nut 5 is interposed between the flanged short pipe 4 and the cap nut 5, or it is provided integrally with the flanged short pipe 4 and/or the cap nut 5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ball valve used in piping lines of various industries such as chemical factories, water and sewage, agriculture / fishery industry, semiconductor manufacturing field, and food field, and more specifically, when a cap nut is removed. The present invention relates to a ball valve capable of removing a flanged short tube while preventing the ball presser from rotating together with rotation of a nut and preventing the ball valve body from popping out during piping.

  Conventionally, there has been a ball valve as shown in FIGS. 10 and 11 (see, for example, Patent Document 1). In this ball valve, when the ball presser 103 is inserted into the valve body 101 and turned, the engaging portion of the ball presser 103 and the engaging portion of the valve main body 101 are engaged, and the ball 102 and the ball presser 103 are popped out. A block type union type ball valve for preventing the ball retainer 103 is engaged with the end 104 of the flanged short tube 106 at the outer end of the ball retainer 103, and the inner flange 105 of the union nut 107 is connected to the flanged short tube. In a ball valve that is locked to the flange portion 104 of the valve 106 and screwed into a male screw on the outer surface of the valve main body 101, the flanged short tube is provided between the flange portion 104 of the flanged short tube 106 and the inner flange portion 105 of the union nut 107. A collar 108 having a lower coefficient of static friction than the flange portion 104 of the union nut 107 and the inner flange portion 105 of the union nut 107 is interposed. At this time, the ball retainer 103 is engaged and retained with the valve body 101 by providing a pair of circumferentially extending protrusions 109 on the inner peripheral surface of the valve body 101, and the ball retainer 103 has a large diameter portion 110. And small-diameter portions 111 are alternately provided in the circumferential direction, and an engagement groove 112 in which the small-diameter portion 111 is extended in the circumferential direction is provided near the outside of the large-diameter portion 110. , The ball holder 103 is inserted into the valve body 101 so that the small-diameter portion 111 and the protrusion 109 are aligned with each other in the circumferential direction. The engagement groove 112 of the ball retainer 103 is engaged with the protrusion 109 of the valve body 101 by turning. The effect is that when the union nut 107 is rotated, the collar 108 is inserted between the flange 104 of the flanged short tube 106 and the inner flange 105 of the union nut 107, so that the union nut 107 is rotated. The accompanying rotation of the ball presser 103 is prevented, and the ball presser 103 and the ball 102 do not jump out.

JP 7-310835 A

  However, in the conventional ball valve, a collar 108 having a low static friction coefficient is interposed between the flange 104 of the flanged short tube 106 and the inner flange 105 of the union nut 107, and the friction generated on the contact surface of the collar 108. In this case, the rotation of the ball presser 103 due to the rotation of the union nut 107 cannot be completely prevented by merely interposing the collar 108. There is. That is, when the ball valve being piped is in a closed state, the upstream side of the ball 102 in the valve body 101 is in a state where fluid pressure is applied. At this time, particularly when the lubricating oil is not sufficiently applied to the O-ring 113 or lubrication is performed. When repairing or replacing a pipe connected to the flanged short pipe 106 in an oil-free ball valve to which no oil is applied, the downstream union nut 107 is removed and the downstream flanged short pipe 106 is removed. Although it is removed, the friction on the contact surface of the collar 108 is not reduced so much depending on the use situation of the ball valve, the difference in the coefficient of static friction between the collar 108 and the collar 104 and the inner collar 105, the shape of the collar 108, etc. There is a risk of co-rotation. Further, in the method of holding the ball presser 103 on the valve main body 101, the ball presser 103 is inserted into the valve main body 101 and rotated and engaged by rotating from a quarter rotation to a half rotation. Therefore, the amount of rotation when holding or removing the ball presser 103 is in a small range from one-quarter rotation to one-half rotation, and the resistance applied when the ball presser 103 is rotated in the removing direction is small. For this reason, depending on the configuration and circumstances of the ball valve, the friction generated on the contact surface of the collar 108 cannot be sufficiently reduced, and the ball presser 103 may be rotated together with the rotation of the union nut 107. The resistance applied when turning in the direction to remove 103 is small, and if the ball retainer 103 is rotated from a quarter rotation to a half rotation, the ball retainer 103 is detached from the valve body 101. There was a problem that the ball 102 and the ball presser 103 may jump out and the fluid may flow out.

  The present invention has been made in view of the above-described problems of the prior art. When the union nut 107 is removed, the ball holder 103 can be prevented from co-rotating, the hooked short tube 106 can be removed, and the ball 102 can be removed. An object of the present invention is to provide a ball valve that prevents the ball from popping out.

  The configuration of the valve of the present invention for solving the above problems will be described with reference to the drawings. A ball valve body 2 for opening and closing a flow path is rotatably disposed in the valve body 1, and a seat 13 is The flanged short tube 4 is provided so as to be pressed against the ball valve body 2, and the cap nut 5 is engaged with the flange 16 of the flanged short tube 4 and screwed to the end of the valve body 1. In the ball valve disposed in contact with the outer end of the ball retainer 3, the ball retainer 3 is screwed onto the inner periphery of at least one end of the valve body 1, and the material of the short tube 4 with a hook or the material of the cap nut 5. First, the sliding member 19 made of a material having a smaller static friction coefficient is interposed between the flanged short tube 4 and the cap nut 5 or is provided integrally with the flanged short tube 4 and / or the cap nut 5. Features

  The second feature is that the static friction coefficient of the material of the sliding member 19 is 12/20 to 20/20 of the static friction coefficient of the material of the flanged short tube 4 or the material of the cap nut 5.

  The third feature is that the surface roughness of the sliding member 19 is 0.1 μm to 6.3 μm.

  Further, the fourth feature is that the sliding member 19 has a thin ring shape and an elliptical cross section.

  Furthermore, a fifth feature is that the ball valve body 2 is rotated by manual, pneumatic, or electric drive.

  In the present invention, the valve body 1 and the ball retainer 3 are joined by screws. However, if a screw is used, for example, even if the ball retainer 3 rotates together with the rotation of the cap nut 5, the thread groove The ball retainer 3 is not detached from the valve body 1 as long as is cut. When the pipe connected to the flanged short tube 4 is repaired or replaced, fluid pressure is applied to the downstream side of the ball retainer 3 (in the direction of the arrow in FIG. 1), so that the ball retainer 3 is unscrewed. Is a resistance that suppresses the rotation of the ball retainer 3 at all times, and is difficult to remove. In addition, each part can be easily molded and processed, and a part with good dimensional accuracy can be obtained, and the ball retainer 3 presses the seat 13 toward the ball valve body 2 by adjusting the tightening of the screw. This is preferable because the force can be adjusted.

  The range of the static friction coefficient of the sliding member 19 of the present invention is preferably in the range of 1 / twentieth to twenty-twentieth of the static friction coefficient of the material of the contact portion with the flanged short tube 4 or the cap nut 5, More preferably, it is in the range of 1/20 to 6/20. In order to facilitate the molding and processing of the sliding member 19, it is necessary to be at least 1/20, and the friction between the sliding surface of the sliding member 19 and the flanged short tube 4 or the cap nut 5 is reduced and the ball presser is reduced. In order to suppress the co-rotation of 3 more reliably, it is necessary to be 12/20 or less. Further, the material of the sliding member 19 of the present invention is a synthetic resin, as long as its static friction coefficient is in the range of 1/20 to 12/20 of the static friction coefficient of the material of the flanged short tube 4 or the material of the cap nut 5. The metal is not particularly limited. For example, if the material of the flanged short tube 4 or the material of the cap nut 5 is a vinyl chloride resin (hereinafter referred to as PVC), polypropylene (hereinafter referred to as PP), polyvinylidene fluoride (hereinafter referred to as PVDF), Polytetrafluoroethylene and the like are preferable. The static friction coefficient of the present invention was measured in accordance with JIS K7125.

  The range of the surface roughness of the sliding member 19 of the present invention is preferably in the range of 0.1 μm to 6.3 μm, and more preferably in the range of 0.2 μm to 6.3 μm. This is because it is necessary to be 0.1 μm or more in order to facilitate the processing of the sliding member 19, and to be 6.3 μm or less in order to further reduce friction by smoothing the contact surface of the sliding member 19. Because there is. In addition, the surface roughness of this invention is arithmetic mean roughness Ra, It measured based on JISB0601 using the surface roughness measuring device.

  In the present invention, the sliding member 19 may be sandwiched between the flanged short tube 4 and the cap nut 5 as shown in FIG. 2, and the sliding member 20 is integrated with the cap nut 21 as shown in FIG. The sliding member 23 may be provided integrally with the flanged short tube 25 as shown in FIG. 5, or the sliding members 26 and 27 may be provided with the flanged short tube 29 as shown in FIG. The cap nut 28 and the cap nut 28 may be integrally provided. The configuration in which the sliding member 19 is sandwiched between the flanged short tube 4 and the cap nut 5 (see FIG. 2) is preferable because the sliding member 19 can be easily replaced even if it is damaged or deteriorated. When the sliding members 20, 23, 26, 27 are provided integrally with the flanged short tubes 22, 25, 29 and / or the cap nuts 21, 24, 28 (see FIGS. 4, 5, and 6) Since the number of parts does not increase, the labor of assembly does not increase, and when a worker who is not used to the work at the site constructs, the cap nuts 21, 24, 28 are removed and the short pipes 22, 25, 29 with hooks are attached. This is preferable because there is no risk of losing the sliding member 19 which is a relatively small part when removing or forgetting to set the sliding member 19 when assembling. Further, as shown in FIG. 6, sliding members 26 and 27 having a small coefficient of static friction are provided on the contact surface between the flanged short tube 29 and the cap nut 28, thereby generating the contact surface between the flanged short tube 29 and the cap nut 28. It is suitable for further reducing friction.

  2, when the sliding member 19 of the present invention is sandwiched between the flanged short tube 4 and the cap nut 5, the shape of the sliding member 19 is the contact between the flanged short tube 4 and the cap nut 5. Although it will not specifically limit if it is the structure provided by interposing in a surface, It is preferable that it is a thin ring shape and a cross-sectional shape is an elliptical shape. This is because the contact surface between the sliding member 19 and the flanged short tube 4 and the cap nut 5 is made close to line contact to reduce the contact area, and the friction generated on the contact surface of the sliding member 19 is reduced. It is preferable because it can be reduced by a certain amount.

  Also, as shown in FIGS. 4, 5, and 6, the sliding members 20, 23, 26, and 27 of the present invention are integrated with the flanged short tubes 22, 25, and / or the cap nuts 21, 24, and 28. The sliding members 20, 23, 26, 27 may be provided on the entire circumference of the flanged short tubes 22, 25, 29 and / or the cap nuts 21, 24, 28 or at equal intervals. There is no particular limitation as long as a sliding effect can be obtained. Moreover, the method of providing integrally is not specifically limited, such as integral molding, melt | fusion, welding, adhesion | attachment, fitting, and screwing. Moreover, you may integrally provide the short pipes 22, 25, 29 and / or the cap nut 21,24,28 and the sliding members 20,23,26,27 with the same material integrally.

  Further, the ball valve of the present invention may be one in which the ball presser 3 is screwed into only one of the end portions of the valve body 1 as shown in FIG. 1, and is screwed into both end portions as shown in FIG. Things can be used.

  Further, the ball valve of the present invention is not limited to the two-way ball valve but also the three-way and multi-way ball valve.

  The ball valve according to the present invention is driven mainly by a manual type, but it may be driven by a pneumatic type (see FIG. 8) or an electric type (see FIG. 9), and is not particularly limited. In the case of the pneumatic type and the electric type, instead of the handle 9 of the ball valve, the pneumatic type driving unit 30 and the electric type driving unit 32 are mounted via mounting bases 31 and 33, respectively, and are conducted to the upper part of the stem 10. The

  The material of the valve body 1, the ball valve body 2, the ball retainer 3, the flanged short tube 4 and the cap nut 5 of the ball valve of the present invention is PVC, but it satisfies the strength and characteristics required for the ball valve. As long as it is a synthetic resin such as PP, PVDF, polyethylene, polyphenylene sulfide, or a metal such as copper, cast iron, or cast steel, it is not particularly limited.

The present invention has the structure as described above, and the following excellent effects can be obtained.
(1) A sliding member having a coefficient of static friction smaller than that of the flanged short tube or the material of the cap nut is interposed between the flanged short tube and the cap nut, or integrated with the flanged short tube and / or the cap nut. When the pipe connected to the short tube with a flange is repaired or replaced, that is, when removing the short tube with the cap nut removed while the fluid pressure is applied to the upstream side, Slip occurs on the contact surface with the sliding member against the rotation of the nut, the co-rotation of the flanged short tube and the ball retainer is suppressed, and the ball retainer does not come off, preventing the ball valve body from popping out And no fluid flows out.
(2) Since the static friction coefficient of the sliding member is from 1/20 to 12/20 of the static friction coefficient of the material of the flanged short tube or the material of the cap nut, when the cap nut is removed, the sliding member comes into contact with the sliding member. Since the friction of the surface is reduced to more surely generate the slip and the co-rotation of the short tube with the flange and the cap nut can be surely suppressed, the ball valve body does not pop out and the fluid does not flow out.
(3) When the surface roughness of the sliding member is 0.1 μm to 6.3 μm, when removing the cap nut, the contact surface of the sliding member is smoothed to reduce friction with the sliding member. Since the slip can be generated more reliably and the co-rotation of the short tube with the flange and the cap nut can be surely suppressed, the ball valve body does not pop out and the fluid does not flow out.
(4) The sliding member has a thin ring shape and an elliptical cross-sectional shape, so that the contact surface between the sliding member, the flanged short tube, and the cap nut is substantially in line contact to reduce the contact area. Since the friction generated on the contact surface of the sliding member is reduced and slipping is generated more reliably, and the co-rotation of the short tube with the hook and the cap nut can be surely suppressed, the ball valve body does not pop out, Fluid does not flow out.
(5) Secondary damage can be prevented by preventing the ball valve body from popping out.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, it is needless to say that the present invention is not limited to the embodiments. FIG. 1 is a longitudinal sectional view showing the ball valve of the present invention when fully closed. FIG. 2 is an enlarged vertical cross-sectional view of the main part of FIG. FIG. 3 is an enlarged vertical sectional view of a main part showing a state in the middle of removing the cap nut of FIG. FIG. 4 is an enlarged vertical cross-sectional view of a main part showing a configuration of a ball valve in which a sliding member is provided integrally with a cap nut. FIG. 5 is an enlarged vertical cross-sectional view of a main part showing a configuration of a ball valve in which a sliding member is integrally provided with a flanged short tube. FIG. 6 is an enlarged vertical cross-sectional view of a main part showing a configuration of a ball valve in which sliding members are integrally provided on a short tube with a flange and a cap nut, respectively. FIG. 7 is a longitudinal sectional view showing a configuration of a ball valve in which a ball presser is provided at both ends of the valve main body when fully closed. FIG. 8 is a partial cross-sectional view showing a configuration of a ball valve by a pneumatic drive. FIG. 9 is a partial cross-sectional view showing a configuration of a ball valve by electric driving.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  Reference numeral 1 denotes a PVC valve body having a diameter of 25 mm. The valve main body 1 has a substantially hollow cylindrical shape and is provided with a valve chamber 6 therein. A through hole into which the stem 10 is inserted is provided in communication with the valve chamber 6 in a direction orthogonal to the flow path axis. . A male screw portion 7 is provided on the outer periphery of both end portions of the valve body 1, and a female screw portion 8 is provided on the inner periphery of one end portion of the valve main body 1.

  2 is a ball valve body made of PVC. The ball valve body 2 is disposed in the valve chamber 6 of the valve body 1 and is fitted to a lower end portion of a stem 10 having a handle 9 fitted on the upper portion thereof. In particular, when the ball valve that is piped is fully closed, that is, when the fluid pressure is applied to the upstream side, the ball valve is fitted in a state of being slightly movable to the downstream side.

  3 is a PVC ball retainer. The ball retainer 3 has a cylindrical shape, and an O-ring 11 is provided on the outer periphery, and a male screw portion 12 that is screwed with the female thread portion 8 of the valve body 1 is provided on the outer periphery. The ball valve body 2 is pressed and held by the seat 13 from both sides of the flow path in the valve chamber 6. An O-ring 14 is disposed on the end surface of the ball retainer 3 on the side where the male thread portion 12 is provided.

  4 is a PVC short tube with a flange. The short tube 4 with the flange is provided with a flange 16 at one end of the short tube portion 15.

  19 is a PP sliding member. The sliding member 19 has a thin ring shape and an elliptical cross-sectional shape, and has a surface roughness of 1.6 μm. Between the flange portion 16 of the flanged short tube 4 and the inner flange portion 18 of the cap nut 5. Intervened and provided.

  5 is a PVC cap nut. The cap nut 5 has a cylindrical shape, and is provided with a female screw portion 17 that is screwed into the male screw portion 7 of the valve body 1 on the inner periphery of one end portion, and protrudes toward the inner peripheral side at the other end portion. An inner collar portion 18 is provided. The cap nut 5 engages the inner flange 18 with the flange 16 of the flanged short tube 4 and is screwed to the valve body 1, so that the flanged short tube 4 is held by the ball retainer 3 via the O-ring 14. It is fixed to the end face.

  Next, the operation when the ball valve of the present invention is opened and closed will be described. When the handle 9 is rotated 90 degrees from the closed state of FIG. 1, the stem 10 fitted to the handle 9 rotates, and the ball valve fitted to the stem 10 as the stem 10 rotates. The body 2 is rotated 90 degrees to open the ball valve.

  Next, in the ball valve of the present invention, when the lubricant is not applied to the O-ring 14, that is, in the state where the oil-free valve is piped, the pipe connected to the flanged short pipe 4 on the downstream side ( The action of removing the cap nut 5 and removing the flanged short tube 4 when repairing or exchanging (not shown) will be described with reference to FIGS. At this time, the flow direction of the fluid is the arrow direction in the figure.

  When the ball valve is closed, that is, when the fluid pressure is applied to the upstream side (left side in FIG. 1) and the fluid pressure is applied, the downstream side (right side in FIG. 1) cap nut 5 is rotated to remove the cap nut. 5, friction occurs on the contact surface between the inner end surface of the inner flange portion 18 of the cap nut 5 and the outer end surface of the flange portion 16 of the flanged short tube 4 and the sliding member 19. Here, the static friction coefficient of PVC, which is the material of the flanged short tube 4 and the cap nut 5, is 0.5, and the static friction coefficient of PP, which is the material of the sliding member 19, is 0.1. The coefficient is 4/20 of the static friction coefficient of the flanged short tube 4 and the cap nut 5, and is within the range of 1/20 to 12/20. The friction of the contact surface is reduced and slippage occurs. By this slip, only the cap nut 5 is rotated, and the rotation of the cap nut 5 is hardly transmitted to the flanged short tube 4 and the rotation of the flanged short tube 4 is suppressed. Since the rotation of the flanged short tube 4 is suppressed, the ball presser 3 pressed through the O-ring 14 does not rotate, and the cap nut 5 can be removed (see FIG. 3), preventing co-rotation. Is done. Then, by removing the flanged short tube 4 from the valve body 1, the flanged short tube 4 can be removed without rotating the ball retainer 3 together.

  Moreover, since the surface roughness of the sliding member 19 is 1.6 μm and is in the range of 0.1 μm to 6.3 μm, the contacted surface of the sliding member 19 is made smooth, Since the friction on the contact surface between the cap nut 5 and the sliding member 19 is further reduced, the sliding of the sliding member 19 can be generated more reliably.

  Further, since the sliding member 19 has a thin ring shape and an elliptical cross section, the contact surface of the sliding member 19 with the flanged short tube 4 and the cap nut 5 is brought into close contact with the line contact. By reducing the area, the friction generated on the abutting surface of the sliding member 19 is further reduced as the contact area of the abutting surface decreases, so that the sliding of the sliding member 19 can be more reliably generated.

  The coefficient of static friction between the sliding member 19 and the flanged short tube 4 and the cap nut 5, the surface roughness of the sliding member 19, and the shape of the sliding member 19 correspond to the relationship between the sliding member 19, the flanged short tube 4 and the cap nut 5. In order to improve the slip of the contact surface, there is an effect on each of them, and by further using these configurations in combination, the slip of the contact surface can be further improved.

  Here, even if the sliding effect is not sufficiently obtained and the rotation of the cap nut 5 is transmitted to the ball presser 3 via the flanged short tube 4, slipping occurs. The force to rotate is small, and the friction force at the portion where the ball retainer 3 is screwed to the valve body 1 is larger, so that the ball retainer 3 can be prevented from rotating. The co-rotation can be suppressed. Even if the ball retainer 3 rotates together, the rotation of the cap nut 5 is not directly transmitted to the ball retainer 3 due to the sliding effect of the sliding member 19, and the fluid pressure is further downstream with respect to the ball retainer 3. When the ball presser 3 is unscrewed, the ball presser 3 always has a resistance to suppress the rotation of the ball presser 3 and the ball presser 3 is screwed to the valve body by a screw. It does not co-rotate so as to be disengaged from the main body 1, and the worst situation that the ball retainer 3 comes off from the valve main body 1 is avoided.

  From the above, when the pipe nut (not shown) connected to the downstream flanged short pipe 4 is repaired or replaced, the cap nut 5 is removed and the flanged short pipe 4 is removed. The rotation of the ball retainer 3 with respect to the rotation is reliably suppressed, and the ball retainer 3 is not detached from the valve body 1. Therefore, the ball valve body 2 is completely prevented from popping out, and no fluid flows out.

It is a longitudinal cross-sectional view which shows the time of the ball valve of the present invention being fully closed. It is a principal part expanded longitudinal cross-sectional view of FIG. FIG. 3 is an enlarged longitudinal sectional view of a main part showing a state in the middle of removing the cap nut of FIG. 2. It is a principal part expansion longitudinal cross-sectional view which shows the structure of the ball valve in which the sliding member was integrally provided in the cap nut. It is a principal part expansion longitudinal cross-sectional view which shows the structure of the ball valve in which the sliding member was integrally provided in the short tube with a hook. It is a principal part expansion longitudinal cross-sectional view which shows the structure of the ball valve in which the sliding member was integrally provided in the short pipe with a hook and the cap nut, respectively. It is a longitudinal cross-sectional view at the time of full closure which shows the structure of the ball valve in which the ball | bowl presser was provided in the both ends of the valve body. It is a fragmentary sectional view which shows the structure of the ball valve by a pneumatic drive. It is a fragmentary sectional view which shows the structure of the ball valve by an electric drive. It is a cross-sectional view showing a conventional ball valve. It is a side view which shows the ball presser of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Valve body 2 ... Ball valve body 3 ... Ball presser 4 ... Short pipe 5 with a hook ... Cap nut 6 ... Valve chamber 7 ... Male thread part 8 ... Female thread Part 9 ... Handle 10 ... Stem 11 ... O-ring 12 ... Male thread part 13 ... Sheet 14 ... O-ring 15 ... Short pipe part 16 ... Ring part 17 ... -Female thread 18 ... Inner collar 19 ... Sliding member

Claims (5)

  A ball valve element that opens and closes the flow path in the valve body is rotatably arranged, and the seat is provided so as to be pressed against the ball valve element by pressing the ball, and the cap nut is engaged with the flange of the flanged short tube. In the ball valve in which the flanged short tube is disposed in contact with the outer end of the ball retainer by being screwed to the end of the valve body, the ball retainer is screwed to the inner periphery of at least one end of the valve body. A sliding member having a smaller coefficient of static friction than the material of the flanged short tube or the material of the cap nut is interposed between the flanged short tube and the cap nut, or the flanged short tube and / or A ball valve characterized by being provided integrally with a cap nut.   2. The ball valve according to claim 1, wherein a coefficient of static friction of the material of the sliding member is 1 / twentieth to twentieth of a coefficient of static friction of the material of the short tube with a flange or the material of the cap nut.   The ball valve according to claim 1 or 2, wherein the sliding member has a surface roughness of 0.1 µm to 6.3 µm.   The ball valve according to any one of claims 1 to 3, wherein the sliding member has a thin ring shape and an elliptical cross section.   The ball valve according to any one of claims 1 to 4, wherein the ball valve body is rotated by manual, pneumatic, or electric drive.

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