JP4812091B2 - Ball valve - Google Patents

Description

  The present invention relates to a ball valve, and more particularly to a technique effective when applied to a seat structure of a seat ring that seals between a ball and a body.

  As one of valves for controlling fluid (liquid, gas) flowing through a pipe, there is a 90 degree open / close ball valve.

  Here, as a conventional ball valve, for example, those described in Patent Document 1 (Patent No. 3053170) and Patent Document 2 (Patent No. 2681155) are known.

  Hereinafter, the ball valves described in Patent Document 1 and Patent Document 2 will be described.

  The ball valve described in Patent Document 1 relates to a primary side seat structure of a floating ball valve, and is made of a seat ring 101 having elasticity such as rubber and a non-metallic material such as resin as shown in FIG. And an outer ring 102 and a body 104 in which an annular groove 105 is formed. The bottom surface 101a of the seat ring 101 and the bottom surface 105a of the annular groove 105 in contact with the bottom surface 105a are formed so as to be inclined toward the ball 103 as the outer diameter is increased, and the bottom surface 101a of the seat ring 101 and the bottom surface 105a of the annular groove 105 are There is a space 106 between which the gap becomes smaller as the outer diameter is increased. Then, the pressure between the inner peripheral surface of the seat ring 101 and the inner surface of the annular groove 105 is pressurized by the upstream fluid pressure, so that the seat ring 101 is pushed outward to press the seat ring 101 against the ball 103. In addition to being sealed, back leakage to the outer ring 102 side flowing through the vacant chamber 106 is also prevented, and the surface pressure between the bottom surface 101a of the seat ring 101 and the bottom surface 105a of the annular groove 105 is also increased. The ring 101 is further pushed toward the ball 103 and hermetically sealed.

  In this ball valve, when the seat ring 101 is assembled (no load), the bottom surface 101a of the seat ring 101 and the bottom surface 105a of the annular groove 105 of the body 104 come into contact with each other. Back sealing performance can be obtained. When further pressure is applied, the seat ring 101 is deformed in the outer diameter direction, and as the outer diameter is increased, the seat ring 101 is deformed so as to block the empty chamber 106 by an inclined surface inclined to the ball 103, and the rear surface As the pressure increases, the seal ring pressure with the ball 103 increases as the seat ring 101 moves toward the ball 103. At this time, the outer ring 102 also tries to move in the direction of the ball 103 and may come into contact with the ball 103, but the ball 103 is not damaged because the outer ring 102 is made of resin or the like. Further, when the pressure on the secondary side increases and the ball 103 is pushed from the opposite side, the ball 103 comes into contact with the metal contact surface 104a of the body 104, and the seat ring 101 and the outer ring 102 are pushed by a certain amount or more. Protected against crushing.

  The ball valve described in Patent Document 2 also has a seat ring having elasticity such as rubber, an outer ring made of a non-metallic material such as resin, and a body having an annular groove. . The bottom of the seat ring and the bottom of the annular groove are formed so as to incline toward the ball as the inner diameter is increased. When the ball is positioned at the center of the stem with the same pressure in the body, the bottom of the seat ring An annular space is provided between the bottom of the groove and the seat ring to be deformed by being pressed by the ball, and the clearance between the ball and the valve seat in the movement direction of the ball is separated from the seat ring. It is comprised so that it may become large in order between a space | interval, an outer ring, and a valve seat part.

Here, Patent Document 3 (Japanese Utility Model Publication No. 3-29646) describes an annular retainer ring fixed to a seat retainer by a bolt. The retainer ring presses against the seat ring, thereby sealing between the seat ring and the seat retainer and preventing the seat ring from falling off the seat retainer.
Japanese Patent No. 3053170 Japanese Patent No. 2681155 Japanese Utility Model Publication No. 3-29646

  However, the techniques described in Patent Document 1 and Patent Document 2 described above are based on the premise that the seat ring is made of an elastic material such as rubber, and valves are used for corrosive fluids and high / low temperature fluids. Therefore, if the seat ring is made of a resin or the like (that is, a material having elasticity lower than that of rubber), the seat ring is unlikely to be deformed to the outer diameter side, and the surface pressure due to pressure is hardly obtained.

  Further, the seal position between the bottom surface of the annular groove and the bottom surface of the seat ring is the outermost diameter of the seat ring. And, under the high pressure condition, if the REIT ring made of a material that is less elastic than rubber, such as resin, is deformed by the pressure between the inner periphery of the annular groove and the seat ring, the sealing position is unlimited as much as possible. As it approaches the outer diameter, pressure enters the gap (vacant space 106). Then, when the valve is opened, a pressure difference is generated between the cavity and the gap, and a force that pushes the seat ring toward the cavity works, so that the seat ring is easily ejected. In addition, when a material such as resin that is less elastic than rubber is used, the gap is not filled, so the force that separates the bottom of the seat ring and the bottom of the annular groove by the pressure that enters the gap works. The contact surface pressure is reduced, and the sealing performance is lowered.

  Furthermore, since the outer ring is not fixed, there is a possibility that the outer ring is locally deformed by the pressure and jumps out to the cavity side in the course of the valve opening / closing operation.

  If the structure is to be applied to a trunnion type ball valve, the body has to be deeply grooved for the outer ring, and the productivity is not good.

  Here, if the technique described in Patent Document 3 is applied to the technique described in Patent Documents 1 and 2 and the seat ring is pressed by the retainer ring, there is a possibility that damage such as pop-out or deformation of the seat ring can be prevented. is there.

  However, according to Patent Document 3, since the retainer ring is fixed to the seat retainer with bolts, in order to prevent the pressing force against the seat ring from becoming unstable, a large number of bolts must be arranged in an annular shape. Therefore, the number of parts and assembly man-hours increase.

  In addition, since the retainer ring holds the outer diameter of the seat ring, if an excessive pressing force is applied by the bolt, the outer ring side bottom surface of the seat ring has a higher surface pressure than the inner diameter side bottom surface. The point may become unstable and pressure may enter the back.

  In addition, the load that causes the seat ring to pop out due to the reaction force or pressure of the seat ring must be received by the bolts that penetrate through the seat retainer, and the load that pulls the bolt is always applied. It is necessary to use a high-strength bolt so that the bolt does not loosen or break due to the movement of the bolt.

  And when the tip of the bolt is close to the ball, if the seat ring wears out, the bolt may interfere with the ball and cause deterioration of sealing performance or malfunction. It is necessary to ensure a wide gap between the outer ring and the ball.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a ball valve that can obtain a stable sealing property and can prevent a seat ring from popping out and being damaged.

  In addition, the present invention provides a ball valve having a retainer ring mounting structure that is excellent in mounting strength and reliability as a seat ring holding function without causing an increase in assembly man-hours and that does not cause interference with the ball. Objective.

In order to solve the above-mentioned problem, the ball valve according to the first aspect of the present invention is rotatably disposed on a flow path formed in the housing, and has a through-hole communicating with the flow path to form the through-hole. A ball that opens and closes the flow path by a hole, a seat ring that is provided on at least the inflow side or the outflow side of the fluid in the ball and presses against the outer peripheral surface of the ball, and a bottom surface that inclines toward the ball side as the outer diameter is increased. An annular seat ring holding groove is formed, and has a sheet holding means for fitting and holding the seat ring in the seat ring holding groove, and a bottom surface of the seat ring holding groove and a bottom surface of the seat ring sealed with, between the bottom surface including the innermost diameter side bottom surface of the seat ring and the bottom surface of the seat ring retention groove and the sheet holding means in contact with the seat ring and A sealing portion that, the outer periphery of the bottom surface of the conjunction gap widens while inclined to the ball side as fall outside diameter located outside diameter and the outer peripheral edge of the bottom surface of the seat ring retaining groove seat ring of the seal portion A first space that is not in contact with the end is formed, and the pressure deformation of the seat ring is absorbed into the first space with the seal portion as a fulcrum.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, a communication groove that connects the first space and the cavity is formed on the outer peripheral surface of the seat ring. It is characterized by.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, a second portion is formed on the inner diameter side of the seal portion by a bottom surface of the seat ring holding groove and a bottom surface of the seat ring. A space is formed.

  According to a fourth aspect of the present invention, the ball valve of the present invention is rotatably disposed on a flow path formed in the housing, and a through hole communicating with the flow path is formed, and the flow path is opened and closed by the through hole. And a seat ring that is provided on at least the inflow side or the outflow side of the fluid in the ball and that is in pressure contact with the outer peripheral surface of the ball, and an annular seat ring holding groove is formed. A retainer that fits into and holds the sheet ring, and a retainer that is formed in a C-shape or divided into a plurality of portions and that has a gap portion and prevents the seat ring from coming off from the seat ring retaining groove A retainer ring holding formed on the sheet holding means and holding the retainer ring by fitting an outer diameter side of the retainer ring. When attached to the sheet holding means so as to be fitted into the gap portion of the retainer ring, and having a spacer to prevent diameter and rotation of said retainer ring.

  According to the present invention, the following effects can be obtained.

  That is, according to the present invention, the bottom surface of the seat ring holding groove and the bottom surface of the seat ring are in contact with each other, and the seal portion that seals between the sheet holding means and the seat ring is located on the outer diameter side of the seal portion. As the outer diameter is increased, a first space is formed in which the gap is widened while being inclined toward the ball side, and the pressure deformation of the seat ring is absorbed in the first space with the seal portion as a fulcrum. It is possible to obtain a ball valve capable of obtaining a stable sealing performance without changing the position of the seat ring and preventing the seat ring from popping out and being damaged.

  Further, according to the present invention, the outer diameter side of the retainer ring is fitted into the retainer ring holding groove, and the spacer is fitted into the gap portion of the retainer ring to prevent the diameter reduction and rotation of the retainer ring. As a result, the number of assembling steps can be reduced, and it is possible to obtain a ball valve having a retainer ring mounting structure which is excellent in mounting strength and reliability as a seat ring holding function and does not interfere with the ball.

  Hereinafter, the best mode for carrying out the present invention will be described more specifically with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. In addition, since description here is the best form by which this invention is implemented, this invention is not limited to the said form.

  1 is a cross-sectional view showing a ball valve according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a main part of the ball valve of FIG. 1, and FIG. 3 is an enlarged view of a main part of the ball valve of FIG. 4 is an explanatory view showing the retainer ring used in the ball valve of FIG. 1, FIG. 5 is an explanatory view showing the relationship between the retainer ring and the bolt of FIG. 4, and FIG. 6 is an attachment of the retainer ring of FIG. FIG. 7 is an explanatory view showing a retainer ring as a modified example, FIG. 8 is an explanatory view showing the relationship between the retainer ring and the bolt considered by the inventor, and FIG. FIG. 10 is an enlarged cross-sectional view showing a main part of a ball valve according to another embodiment of the present invention.

  First, the configuration of the ball valve in one embodiment of the present invention will be described.

  In the ball valve of the present embodiment shown in FIG. 1, the housing 12 is composed of a body 12a and a body cap 12b, and has a structure in which a cylindrical flow path 13 is formed. The structure of the housing is appropriately selected from a structure such as a side entry type in which a ball is inserted by being divided in the flow direction (lateral direction) and a top entry type in which a ball is inserted by being divided in a vertical direction. The

  Inside the housing 12, a ball 14 having a cylindrical through hole 14 a communicating with the flow path 13 is disposed on the flow path 13. The ball 14 is supported by a pair of stems 15a and 15b arranged in a direction orthogonal to the flow path 13, and pivots in a direction to open and close the flow path 13 through the through hole 14a with the stems 15a and 15b serving as pivot points. It is installed freely. Here, the ball 14 is made of metal or resin, and in the case of metal, for example, stainless steel, carbon steel, ductile iron, iron, bronze, brass, or a core made of these metals is formed by stellite or plating. When the surface-treated product is made of resin, for example, a fluororesin, nylon resin, plastic, or a metal core covered with them is used.

  A cavity 16 that is a space surrounded by the housing 12 and the balls 14 is formed around the stems 15a and 15b.

As shown in FIG. 2, a seal between the passage 13 and the cavity 16 in the seal portion S _1, to prevent fluid from leaking from the channel 13 to the cavity 16, an annular seat ring 17, These are in pressure contact with the outer peripheral surface of the ball 14, and are provided on the fluid inflow side and the outflow side (the body 12 a and the body cap 12 b side) of the ball 14. Accordingly, the ball 14 rotates while sliding with the seat ring 17.

  For the material of the seat ring 17, resins such as PCTFF, PTFE, modified PTFE (PFA + PTFE), filled PTFE, polyether, and nylon can be used. That is, the seat ring 17 can be made of a resin material containing fluorine, nylon, ether, or the like.

  Here, since PCTFF has good dimensional stability at low temperatures and high mechanical strength, it is mainly suitable for use at ultra-low temperatures. PTFE is versatile and resistant to wear, and is suitable for the use of ultrapure water, chemicals, and chemicals that dislike colored foreign matters generated by abrasion of the sheet. Modified PTFE (PFA + PTFE) is the same application as PTFE, and is suitable for use when creep resistance and use at high temperatures (up to about 230 ° C.) are required. Even low temperatures can be used up to about −100 ° C. Filled PTFE uses glass fiber, carbon fiber, or the like as the filler depending on the corrosion resistance with the fluid, etc., has excellent strength and wear resistance, and is suitable for use at about −100 to 230 ° C. The polyether resin is suitable for use at high pressure and high temperature (up to about 270 ° C.) and has excellent strength and high temperature characteristics. Nylon resins are mainly suitable for use at high pressure.

  However, the material of the seat ring 17 is not limited to these, and various materials other than these (various resins and metals other than rubber products alone) can be used.

  The seat ring 17 is held by an annular seat retainer (sheet holding means) 20. That is, an annular seat ring holding groove 20a is formed in the seat retainer 20 so as to open in the axial direction of the flow path 13, and the seat ring 17 is fitted into the seat ring holding groove 20a and held by the seat retainer 20. ing.

  Further, an annular retainer ring holding groove 20d is formed in the seat retainer 20 in the direction orthogonal to the outer diameter side of the seat ring holding groove 20a, and the retainer ring 19 is fitted therein. That is, the outer diameter side of the retainer ring 19 is fitted into the retainer ring holding groove 20 d, and the seat ring 17 is in contact with the inner diameter side of the retainer ring 19. This prevents the seat ring 17 from falling off the seat ring holding groove 20a. The details of the retainer ring 19 will be described later.

  The seat retainer 20 is provided so as to be displaceable in the axial direction of the flow path 13, and a plurality of spring holding holes 20 b are formed on the opposite side of the seat retainer 20 from the balls 14. The spring holding hole 20b is provided with a spring 21 that presses against the housing 12 and applies an urging force to displace the seat retainer 20 in the direction of the ball 14. Thereby, especially at the time of low pressure, the seat retainer 20 is positively moved to the ball 14 side by the spring 21 and the seat ring 17 is pressed against the ball 14. The spring 21 uses a coil spring, but a leaf spring or a disc spring may be used.

  An annular seal holding groove 20 c is formed on the outer periphery of the seat retainer 20. An O-ring 18 that seals between the housing 12 and the seat retainer 20 is fitted in the seal holding groove 20c. Accordingly, the fluid pressure is prevented from leaking from between the seat retainer 20 and the housing 12 to the cavity 16, and a force for displacing the seat retainer 20 toward the ball 14 is applied.

In the embodiment according to the first invention of the present application, as shown in detail in FIG. 3, the bottom surface 20a-1 of the seat ring holding groove 20a and the bottom surface 17-1 of the seat ring 17 become closer to the ball 14 side as the outer diameter becomes larger. The bottom surface 17-1 of the seat ring 17 is largely inclined toward the ball 14. Specifically, in the present embodiment, the inclination angle theta ₁ of the bottom surface 20a-1 of the seat ring holding groove 20a is 50 °, the inclination angle theta ₂ of the bottom surface 17-1 of the seat ring 17 is 45 ° . However, the inclination angles θ ₁ and θ ₂ can be freely set, and are not limited to the angles shown in the present embodiment.

The bottom surface 20a-1 of the seat ring holding groove 20a and the bottom surface 17-1 of the seat ring 17 are in contact with each other so that the space between the seat retainer 20 and the seat ring 17 is in contact with each other. seal portion S ₂ for sealing is formed.
As shown in FIG. 3, the seal portion S ₂ includes a bottom surface 20a-1 of the bottom face 17-1 and the sheet ring retaining groove 20a containing a radially innermost side bottom is formed in contact with the seat ring 17.

Further, the structure of the bottom surface 17-1 of such seat ring holding groove 20a of the bottom surface 20a-1 and the seat ring 17, the outer diameter side of the seal portion S _2, inclined ball 14 side as fall outside diameter However, a first space 31 in which the gap is widened is formed, and on the inner diameter side, the second space surrounded by the acute angle portion of the radial cross section of the seat ring holding groove 20a and the acute angle portion of the radial cross section of the seat ring 17 is formed. A space 32 is formed.

  On the outer peripheral surface of the seat ring 17, a plurality of communication grooves 17 a that communicate the first space 31 and the cavity 16 are formed at predetermined intervals, and the first space 31 has the same pressure as the cavity 16. Yes. However, the communication groove 17a may be only one instead of a plurality.

The bottom surface 20a-1 of the seat ring holding groove 20a and the bottom surface 17-1 of the seat ring 17 are inclined toward the ball 14 as the outer diameter is increased, and the inclination angle of the bottom surface 17-1 of the seat ring 17 is larger. since it is made, the first space 31, the radial cross section has a shape substantially triangular in which the seal portion S ₂ vertices.

Further, the shape of the acute angle portion of the seat ring holding groove 20a and the shape of the acute angle portion of the seat ring 17 may be the same to eliminate the second space 32. However, by forming the second space 32 as in this embodiment, the width of the annular seal portion S ₂ is narrower than in the case there is no such space. Thus, even when the position of the seal portion S ₂ seat ring 17 is deformed by being pressed by the ball 14 is moved to the back, room for the area of the seal portion S ₂ is increased less, i.e. of the seal portion S ₂ This is desirable because the cross-section becomes difficult to be a wide flat surface and the reduction of the seal surface pressure is prevented.

  Here, in the embodiment according to the second invention of the present application, the retainer ring 19 fitted into the annular retainer ring holding groove 20d formed in the seat retainer 20 is formed in a C shape as shown in FIG. The gap portion 19a is provided. The retainer ring 19 is made of metal, and has flexibility that can be restored even if the diameter is reduced when fitted. In the state where the retainer ring is held in the retaining groove 20d, the bolt (spacer) 25 is attached to the seat retainer 20 so as to be fitted into the gap portion 19a. That is, a bolt mounting hole (not shown) is formed in the retainer ring holding groove 20d, and when assembling, the retainer ring 19 is reduced in diameter so as to narrow the gap 19a, and is fitted into the retainer ring holding groove 20d. Include. And the said bolt attachment hole is exposed so that the clearance gap 19a may become a position of a bolt attachment hole. After that, when the bolt 25 is attached to the bolt attachment hole, the gap portion 19a is blocked, and the retainer ring 19 is prevented from being reduced in diameter and rotating so as not to fall off (see FIG. 5). It is fixed to the retainer ring holding groove 20d.

  In this embodiment, the bolt 25 is used as the spacer. However, it is sufficient that the gap 19a of the retainer ring 19 can be closed. For example, a pin that can be fitted with one touch can be used.

  Next, the operation of the ball valve in one embodiment of the present invention will be described.

  In the ball valve having the above-described structure, the ball 14 is rotated by the stems 15a and 15b so that the through hole 14a is not in communication with the flow channel 13 and the flow channel 13 is closed.

At this time, in the embodiment according to the first invention of the present application, in the state where the fluid pressure on the inflow side is not applied to the ball valve or the pressure on the inflow side is the same as the pressure in the cavity 16. As shown in FIG. 2, the seat retainer 20 is pressed in the axial direction toward the ball 14 by the load generated by the elastic force of the spring 21, whereby the seal portion S ₁ of the seat ring 17 is pressed against the ball 14. The In a state where the fluid pressure of the inflow side is applied, the sheet retainer 20 further receives a load by the fluid pressure between the seal diameter of the seal outer diameter and the seal portion S ₁ of the O-ring 18, the seat ring 17 The seal portion S ₁ is more strongly pressed against the ball 14.

At this time, the seal portion _{S 2} formed by the bottom surface 17-1 of the seat ring holding groove 20a of the bottom surface 20a-1 and the seat ring 17, between the seat retainer 20 and the seat ring 17 is sealed.

Here, the force pushing the seat ring 17 on the cavity 16 side by the fluid pressure dependent on the difference between the sealing diameter of the seal diameter and the seal portion S ₁ of the seal portion S _2, greater the difference between the sealing diameter is small, extruded force Becomes smaller. In the present embodiment, the outer diameter side of the seal portion S _2, since the first space 31 which gap widens while inclined as the ball 14 side becomes the outer diameter is formed, inevitably seal part S ₂ becomes a side close to the inner diameter of the seat ring 17, the difference between the sealing diameter of the seal portion S ₁ between the seat ring 17 and the ball 14 is reduced. Thereby, since the force which pushes out the seat ring 17 to the cavity 16 side is suppressed, the jump-out of the seat ring 17 and the damage accompanying this are prevented beforehand.

Further, as shown in FIG. 3, the outer space of the seal portion S < _b > ₂ has a gap that becomes wider toward the outer side of the ball 14 while being inclined toward the ball 14. 31 and the outer peripheral edge of the bottom surface 17-1 of the formed sheet ring holding groove 20a of the bottom surface 20a-1 of the outer peripheral edge and the sheet ring 17 is rendered non-contact, further, the seat ring 17 is a reaction force from the seal portion S ₁ F is received, and this reaction force F acts in the direction perpendicular to the tangent line passing through the seal portion S ₁ of the ball 14.

Therefore, the reaction force F is axial force component is sealed portion S ₂ direction F _alpha, and be divided into a radial component force F _beta is a contact portion direction of the outer periphery and the sheet retainer 20 of the seat ring 17. The axial component force F _alpha which joined the seat ring 17, by wedge action due to the inclination of the bottom surface 20a-1 of the seat ring holding groove 20a seat ring 17 with movement in the axial direction is restricted in the seal portion S ₂ The seal surface pressure increases.

The radial component force F _beta, the seat ring 17 acts to deform the outer circumferential direction, near the far bottom 17-1 from the sealing portion S ₁ in the axial direction toward the outer circumference by the pressing of the seal portion S ₂ deformation is restricted, the surface pressure of the seal portion S ₂ rises.

Furthermore, weighting of contact between the more seat ring 17 and the ball 14 becomes a high pressure (i.e., the surface pressure of the seal portion S ₁₎ is increased, the sheet ring 17 to deform more outer circumferential direction. However, the deformation of the outer peripheral direction in addition to the regulation by the aforementioned seal portion S _2, because it is blocked by the sheet retainer 20, the seat ring as the seat ring 17 fills the first space 31 as a fulcrum seal portion S ₂ The holding groove 20a falls to the bottom surface 20a-1 side.

  Here, since the first space 31 is secured more than the deformation amount of the seat ring 17, the pressure deformation of the seat ring 17 is absorbed into the first space 31, and the bottom surface 20a of the seat ring holding groove 20a. -1 and the bottom surface 17-1 of the seat ring 17 always maintain a constant clearance.

Therefore, it reduces the surface pressure width of the seal portion S ₂ is an enlarged, without such difference in seal diameter to expand the seal portion S ₁ by the seal portion S ₂ is moved in the outer circumferential direction, a constant and seal portion S ₂ is maintained, will be surely surface pressure is applied regardless of the pressure or temperature, stable sealing property can be obtained.

In this way, if not the bottom surface 20a-1 of the seat ring holding groove 20a is inclined, that is, if the inclination angle theta ₁ is is 90 °, since no work is wedge effect described above, the bottom surface of the seat ring 17 17- 1 moves in the radial direction in the vicinity of no longer restricted, the seal surface pressure of the seal portion S ₂ does not increase. That is, a stable sealing property cannot be obtained.

The second space 32 is in contact with the inner diameter of the seat ring holding groove 20a, the seal portion S ₂ does not move, is not that the second space 32 is increased. Therefore, the force that pushes out the seat ring 17 works in the axial direction, and the force in the direction tangential to the ball 14 that tends to jump out is prevented.

  Here, as described above, the communication groove 17 a is formed on the outer peripheral surface of the seat ring 17, and the first space 31 has the same pressure as the cavity 16, so that pressure enters the first space 31. No force is generated to push out the seat ring 17 from the seat ring holding groove 20a.

  Now, in the process of opening the ball valve from closing to closing, the force that momentarily pushes the seat ring 17 into the cavity 16 due to the negative pressure generated between the seat ring 17 and the ball 14 or the pressure accumulated in the second space 32. Work. At this time, in the present embodiment, the seat ring 17 abuts on the annular retainer ring 19 to prevent popping out.

  In the embodiment according to the second invention of the present application, the retainer ring 19 has a retainer ring retaining groove in a state where the gap portion 19a is blocked by the bolt 25 and the diameter reduction and rotation of the retainer ring 19 are prevented. Since it is fitted in 20d, a sufficient clearance L is ensured between the balls 14 as shown in FIG. On the other hand, as shown in FIGS. 8 and 9, when the retainer ring 19 is fixed with the bolt 25, the tip of the bolt 25 protrudes, so that a necessary clearance between the ball 14 is required. L is difficult to be secured. Therefore, in the present application, there is no possibility of interference between the bolt 25 and the ball 14, and deterioration of the sealing performance and malfunction due to this interference. Therefore, in order to obtain a necessary clearance, the dimensions of the retainer ring and the seat retainer need not be increased toward the outer diameter side.

In addition, when the bolt is fixed from above the retainer ring, a large number of bolts are arranged in an annular shape, so that the strength for holding the seat ring 17 against the force of the seat ring 17 to jump out is required. in the embodiment, which is fitted a retainer ring 19 to the retainer ring holding groove 20d, further, aggressively since the surface pressure is applied to the seal portion S ₂ by the reaction force from the seal portion S ₁ as described above, the seat ring Since the initial pressing force for 17 is not required, and it is not necessary to arrange a large number of bolts, the number of parts is reduced and the number of assembly steps is not increased.

  Further, when the bolt is fixed from above the retainer ring, the bolt not only needs to have a predetermined strength, but also the bolt may loosen due to vibration or movement of the retainer ring. 25 is fitted in the gap 19a of the retainer ring 19, so that the bolt 25 receives only a shear load from both sides, so that the bolt 25 is not insufficiently pulled or loosened. Since the shear load is only the force that the retainer ring 19 tries to rotate, a large stress is not applied until the bolt 25 is sheared, so that the mounting strength is improved and the ball 14 and the seat retainer 20 are connected. The reliability of the retainer ring 19 as a holding function of the seat ring 19 to be sealed is improved.

  As shown in FIG. 7, the retainer ring 19 may be divided into a plurality of parts (here, divided into three parts), and the bolts 25 may be attached to the gaps 19a. With such a structure, it is sufficient to use a plurality of the same arc-shaped parts, so that the material cost is reduced and the flexibility may be low, so that a rigid ring can be easily assembled and disassembled. It becomes like this.

  As described above, any member other than the bolt 25 may be used as long as it can block the gap portion 19a of the retainer ring 19. However, if the bolt 25 is used, it can be reused, and it is easy to attach and remove, and is excellent in maintainability.

  In the above description, the first space 31 is inclined toward the ball 14 side as the outer diameter is increased (see FIG. 3), but the first space 31 has an outer peripheral end of the bottom surface 20a-1 of the seat ring holding groove 20a. It is sufficient that the outer peripheral end of the bottom surface 17-1 of the seat ring 17 is not in contact, and the gap does not have to become wider as the outer diameter is increased. That is, as shown in FIG. 10, the seat ring holding groove can be used regardless of whether the bottom surface 17-1 of the seat ring 17 has a concavely curved cross-sectional shape, a stepped shape, or other various shapes. The outer peripheral end of the bottom surface 20a-1 of 20a and the outer peripheral end of the bottom surface 17-1 of the seat ring 17 may be non-contact.

  In this embodiment, the case where the present invention is applied to a trunnion type ball valve is shown, but the present invention can be applied to a ball valve having various structures such as a floating type.

It is sectional drawing which shows the ball valve in one embodiment of this invention. It is sectional drawing which shows the principal part of the ball valve of FIG. It is sectional drawing which expands and shows the principal part of the ball valve of FIG. It is explanatory drawing which shows the retainer ring used for the ball valve of FIG. It is explanatory drawing which shows the relationship between the retainer ring of FIG. 4, and a volt | bolt. It is sectional drawing which shows the attachment structure of the retainer ring of FIG. It is explanatory drawing which shows the retainer ring as a modification. It is explanatory drawing which shows the relationship between the retainer ring and the volt | bolt which this inventor examined. It is sectional drawing which shows the attachment structure of the retainer ring which this inventor considered. It is sectional drawing which expands and shows the principal part of the ball valve in other embodiment of this invention. It is sectional drawing which shows the ball valve of patent document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Housing 12a Body 12b Body cap 13 Flow path 14 Ball | bowl 14a Through-hole 15a, 15b Stem 16 Cavity 17 Seat ring 17-1 Bottom surface 17a Communication groove 18 Ring 19 Retainer ring 19a Clearance part 20 Sheet retainer (sheet holding means)
20a Seat ring retaining groove 20a-1 Bottom surface 20b Spring retaining hole 20c Seal retaining groove 20d Retainer ring retaining groove 21 Spring 25 Bolt (spacer)
31 first space 32 second space S ₁ seal portion S ₂ seal portion

Claims (4)

A ball rotatably disposed on a flow path formed in the housing, and a through hole communicating with the flow path is formed to open and close the flow path by the through hole;
A seat ring that is provided on at least the inflow side or the outflow side of the fluid in the ball and is in pressure contact with the outer peripheral surface of the ball;
An annular seat ring holding groove having a bottom surface inclined toward the ball as the outer diameter is formed, and has a sheet holding means for fitting the seat ring into the seat ring holding groove and holding the seat ring;
Between the bottom surface of the seat ring retaining groove and the bottom surface of the seat ring, the bottom surface including the bottom surface on the innermost diameter side of the seat ring and the bottom surface of the seat ring retaining groove are in contact with each other between the sheet retaining means and the seat ring. a sealing portion for sealing the bottom surface of the seat ring and the outer peripheral edge of the bottom surface of the seat ring holding groove with a gap widens while inclined to the ball side as fall outside diameter located on the outer diameter side of the seal portion A first space that is not in contact with the outer peripheral edge of the
The pressure deformation of the seat ring is absorbed in the first space with the seal portion as a fulcrum,
A ball valve characterized by that.   The ball valve according to claim 1, wherein a communication groove that connects the first space and the cavity is formed on an outer peripheral surface of the seat ring.   The ball valve according to claim 1 or 2, wherein a second space is formed on the inner diameter side of the seal portion by a bottom surface of the seat ring holding groove and a bottom surface of the seat ring. A ball rotatably disposed on a flow path formed in the housing, and a through hole communicating with the flow path is formed to open and close the flow path by the through hole;
A seat ring that is provided on at least the inflow side or the outflow side of the fluid in the ball and is in pressure contact with the outer peripheral surface of the ball;
An annular seat ring holding groove is formed, and a sheet holding means for fitting the seat ring into the seat ring holding groove and holding it,
A retainer ring that is formed in a C-shape or divided into a plurality of gaps, the seat ring abuts and prevents the seat ring from falling off the seat ring holding groove;
A retainer ring holding groove formed on the sheet holding means and fitted with an outer diameter side of the retainer ring to hold the retainer ring;
A ball valve comprising: a spacer attached to the seat holding means so as to be fitted into the gap portion of the retainer ring, and a spacer for preventing the diameter reduction and rotation of the retainer ring.

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