JP2012013141A - Trunnion type ball valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trunnion type ball valve which can reliably seal high-pressure fluid from a primary side and a secondary side according to a double seal method established by a repulsive force by the use of a spring and a fluid pressure, secure sealing property by generating a prescribed pressing force on the basis of the fluid pressure and adjust the pressing force to an optimum sealing surface pressure while securing the whole compactness and the strength of a seat retainer, suppressing the rise of a valve operation torque to enhance the durability and maintaining superior operability.SOLUTION: The trunnion type ball valve includes: a ball 12 disposed freely rotatably via a stem 11 in a body 14; and a seal mechanism 13 which is arranged on both side positions of the ball 12 such that the ball 12 comes into sealing contact with the seal mechanism 13. The seal mechanism 13 includes a ball sheet 25, a seat retainer 18, a spring member 22 and a seal member 20. The pressing force of the seal mechanism 13 is constituted with the repulsive force applied to the sheet retainer 18 by the spring member 22 and the fluid pressure set on the inner diameter side of the seal member 20.

Description

  The present invention relates to a ball valve, and more particularly to a high-pressure trunnion-type ball valve suitable for high-pressure gas (hydrogen) such as a hydrogen station.

Conventionally, for example, in a piping facility in which a high-pressure fluid such as hydrogen of 90 MPa or more flows, a high-pressure trunnion-type ball valve is generally used. In this type of ball valve, generally, a ball valve body is rotatably supported in a body by a stem and a trunnion, and a retainer member and a ball seat are mounted in the body. The retainer member and the ball seat Is structured to be attached in close contact with the ball valve body through the spring force of the spring. At this time, a sealing O-ring is mounted between the retainer member and the body.
With this structure, the ball valve has a sealing direction called a double seal system on the upstream and downstream sides of the valve. The double seal method is a so-called self-tensioning force in which the initial squashing force of the ball seat is crushed with a spring force and brought into close contact with the ball valve body together with the retainer member, and the ball valve body and the ball seat are brought into close contact with the pressing force of the fluid. Therefore, the high-pressure ball valve uses the pressure of the high-pressure fluid to improve the sealing performance. At this time, this ball valve is a so-called double valve in which the ball seat is pressed against the ball valve body and exerts self-tightening force regardless of the fluid pressure from either the primary side or the secondary side. Normally, the seal structure is used, and when the fluid pressure from either the primary side or the secondary side is applied by this double seal structure, the double seal works by this fluid pressure. ing.

As a double seal type ball valve, for example, the ball valve shown in FIG. 12 and the ball valve shown in Patent Document 1 are known.
The ball valve 1 shown in FIG. 12 is intended to obtain sealing performance by the spring force of the coil spring 2 and the self-tightening force, and is a stage for mounting the O-ring 4 formed on the outer peripheral side of the retainer member 3. Self-tensioning force is generated by the shaped part 5. In this ball valve 1, when H ₁ is the outer diameter on the enlarged diameter side of the stepped portion 5 of the retainer member 3 and H ₂ is the outer diameter on the reduced diameter side of the stepped portion 5 of the retainer member 3, the retainer in FIG. When pressure is applied from the right side to the left side of the member 3, the ball seat 6 and the ball valve body 7 are sealed at the position of the diameter h ₁ (inner peripheral position of the seal portion), and the seat pressing force (self-tightening) at this time Force) F ₁ is expressed as sheet pressing force F ₁ = ¼ · π (H ₁ ² −h ₁ ² ) × ΔA ₁ . Here, ΔA ₁ is a differential pressure, and this differential pressure ΔA ₁ is the pressure on the right side of the retainer member 3 (pressure in the flow path) −the pressure on the left side of the retainer member 3 (pressure in the cavity 8).
On the other hand, when pressure is applied from the left side to the right side of the retainer member 3, the ball seat 6 and the ball valve body 7 are sealed at the position of the diameter h ₂ (the outer peripheral position of the seal portion) via the cavity 8. The sheet pressing force F ₂ is expressed as sheet pressing force F ₂ = ¼ · π (h ₂ ² −H ₂ ² ) × ΔA ₂ . At this time, the differential pressure ΔA ₂ is the pressure on the left side of the retainer member 3 minus the pressure on the right side of the retainer member 3.
Thus, the self-tightening force is the difference between the pressure difference between the primary side and the secondary side via the retainer member 3 and the area difference between the primary side and the secondary side of the retainer member 3 when this differential pressure is applied. Expressed by product.

  The ball valve in Patent Document 1 includes a ball valve body, a retainer member, a ball seat, and a disc spring, and tries to bring the ball seat into close contact with the ball valve body by the spring force of the disc spring and the self-tightening force of fluid. Is. In this ball valve, when the pressure in the flow path exceeds the pressure in the cavity, the retainer member is urged in the seal engagement direction with the valve element by an unbalanced flow pressure pressure load, and the working load sealing force is Each of the unbalanced channel pressure load and the unbalanced cavity pressure load is in parallel. In other words, this valve is intended to enhance the sealing performance against high-pressure fluid by exerting in parallel the working seal load due to the spring force and the flow path pressure load (self-tightening force) due to the fluid pressure.

  The trunnion type ball valve having the above-described structure attempts to improve the sealing performance against high-pressure fluid by improving the adhesion between the ball valve body and the ball seat by the double seal structure. It is also necessary to consider the operability due to the rotational torque of the body, and it is also necessary to improve the durability against the rotational torque to ensure smooth operability.

US Patent Application Publication No. 2010/90146

However, the ball valve of Patent Document 1 and FIG. 12 is provided with a stepped portion 5 for mounting the O-ring 4 on the retainer member 3 to seal the inner and outer peripheral sides of the O-ring 4 in FIG. and the surface, the difference due to the outer diameter H ₁ of the enlarged diameter side of the stepped portion 5, the outer diameter of H ₂ reduced diameter, the diameter h _1, h ₂ is the sealing portion of the ball seat 6 and the ball valve body 7 Therefore, if the difference in diameter is too large, the area to which the differential pressure is applied becomes large, and the sheet pressing force due to the self-tightening force becomes excessive. Therefore, the operation torque is increased, the operability is impaired, the durability of the ball seat 6 is also deteriorated, and the life may be shortened.

To prevent this increase of the own緊力, but is possible to reduce the diameter ratio of the outer diameter H ₁ to the diameter h ₁ and formed small outer diameter H ₁ is considered, in this case, reduced diameter of the outer diameter H ₁ As a result, the diameter-reduced cylindrical portion 9 formed to secure the dimensions of the stepped portion 5 for mounting the O-ring is also reduced in diameter, and the reduced-diameter cylindrical portion 9 can withstand excessive stress during high-pressure loads due to its thinning. There is a risk of not being able to complete. For this reason, when the inner diameter and outer diameter of the O-ring 4 are increased in order to reduce the stress applied to the reduced diameter cylindrical portion 9, the ball valve body 7 and the ball seat 6 need to be increased in accordance with this size. As the whole size increases, the operability also deteriorates.
On the other hand, when the outer diameter H ₂ is made larger and the expansion ratio of the diameter h ₂ to the outer diameter H ₂ is made smaller, the outer diameter H ₁ becomes larger due to the expansion of the outer diameter H _2. As in the case of forming a large diameter, the entire valve is enlarged and the operability is deteriorated.

While avoiding an increase in the overall size of the valve, the outer diameter H ₁ to the diameter h _1, in order to try to reduce the diameter ratio of the outer diameter H ₂ diameter h ₂ with respect to, conceivable to use a small O-ring cross-sectional dimension However, in this case, forcibly reducing the cross-sectional dimension of the O-ring leads to deterioration of the sealing performance by the O-ring, which is difficult to realize.

Further, as described above, these valves have a structure in which an O-ring 4 is mounted in a space between the outer diameter H ₁ and the outer diameter H _{2. The} diameters of the outer diameters H ₁ and H ₂ Since the difference in diameter affects the sealing function of the O-ring 4, there is also a problem that it is difficult to select the size of the O-ring 4. In order to improve the sealing performance by the O-ring 4, it is possible to increase the difference between the outer diameter H ₁ and the outer diameter H ₂ and mount an O-ring having a large cross section. The thickness of 9 becomes so thin that it cannot withstand excessive stress.

  Thus, since these ball valves are formed with the stepped portion 5 for mounting the O-ring on the retainer member 3 side, it is difficult to adjust the self-tightening force through the stepped portion 5. As a result, it has been difficult to set the surface pressure between the ball seat 6 and the ball valve body 7 to an optimum state.

  Further, in the ball valve of Patent Document 1, the diameter of the ball seat is large. By forming the diameter of the reduced diameter cylindrical portion corresponding to the seal position between the ball seat and the ball valve body, a predetermined diameter is obtained. It is possible to gain self-reliance. However, when the seal diameter of the ball seat with respect to the substantially spherical ball valve body is increased in this way, the ball seat is easily held by the valve body and sucked. As a result, the wear of the ball seat is likely to proceed, and the sealing performance may be deteriorated or the operation torque may be increased.

  In addition, the ball valve of the document 1 attempts to obtain a sealing force by exerting in parallel a working seal load due to the spring force of the disc spring and a self-tightening force due to fluid pressure. When the force is reduced, the entire sealing performance is adversely affected, and it is difficult to ensure stable sealing performance and torque performance during operation.

  The present invention has been developed to solve the above-described problems, and the object of the present invention is from a primary side and a secondary side by a double seal system using a spring force and fluid pressure. High-pressure fluid can be reliably sealed, and while ensuring the overall compactness and strength of the seat retainer, a predetermined pressing force is generated by the fluid pressure and adjusted to the optimum seal surface pressure to ensure stable sealing performance Another object of the present invention is to provide a trunnion-type ball valve capable of suppressing the increase in valve operation torque to enhance durability and maintaining excellent operability.

  In order to achieve the above object, the invention according to claim 1 is a trunnion type in which a ball is rotatably provided in a body main body via a stem, and seal mechanisms for sealing contact with the ball are arranged at both side positions of the ball. A ball valve having a ball mechanism in sealing contact with the ball surface, a seat retainer with the ball seat attached to the tip, and a spring attached to the seat retainer to provide a resilient force to the ball seat side It consists of a member and a seal member mounted in the mounting groove on the inner peripheral surface of the body main body located on the outer peripheral surface of the seat retainer, and the spring force that the spring member imparts to the seat retainer is set on the inner diameter side of the seal member It is a trunnion type ball valve that uses the pressure of the seal mechanism as a result of the fluid pressure.

  The invention according to claim 2 is a trunnion type ball valve in which the body body is provided with a cap member on each of the primary side and the secondary side of the body, and a mounting groove for mounting a seal member is formed on the inner peripheral surface of the cap member. is there.

  The invention according to claim 3 is a trunnion-type ball in which a mounting groove for mounting a seal member is formed by a step formed on the inner peripheral surface of the cap member and an annular stopper provided between the body and the engaging portion of the cap member. It is a valve.

  The invention according to claim 4 is a trunnion-type ball valve in which an O-ring having a sealing member as an O-ring and an O-ring having backup rings on both sides is mounted in a mounting groove.

  The invention according to claim 5 is a trunnion type ball valve in which a manual handle or an actuator is attached to an upper end portion of a stem to form a manual or automatic valve.

  According to the first aspect of the present invention, the double seal system is based on the spring force of the spring and the fluid pressure, and the sealing mechanism for sealing contact with the ball is disposed at both side positions of the ball, so that The high-pressure fluid from the secondary side can be reliably sealed, and this sealing mechanism uses the spring force of the spring member and the pressure set by the fluid pressure set on the inner diameter side of the seal member. On the other hand, the strength of the sheet retainer can be ensured by ensuring a sufficient thickness. During sealing, the fluid pressure on both the primary side and the secondary side is set by the inner diameter side of the seal member, so that the pressing force by the fluid pressure can be reduced and maintained at a predetermined size. Stable operability can be ensured by adjusting the pressing force due to the force and the spring force of the spring member to ensure a stable sealing performance with the optimum seal surface pressure, and reducing the operating force by suppressing the increase in valve operating torque It is possible to improve the durability of the operation by securing the high performance trunnion type ball valve suitable for the ultra high pressure fluid. For this reason, the freedom degree in the material selection of a ball seat increases, and the product with higher performance can also be manufactured.

  According to the second aspect of the present invention, since the cap member can be removed from the body and the seal member can be attached to and detached from the mounting groove of the cap member, the seal member can be used even when the seal member is consumed due to repeated valve opening / closing operation or aging deterioration. The member can be easily replaced, and the sealing property by the seal member can be maintained and the self-tightening force by the fluid pressure can be stably exhibited.

  According to the invention of claim 3, the cap member is removed from the body by forming a mounting groove for mounting the seal member with the stepped portion of the cap member and the annular stopper, and the annular stopper is removed from the cap member, By attaching the seal member to the stepped part of the cap member from the opening side, the seal member can be smoothly installed while preventing deformation and damage, and the seal member is disposed at a predetermined position by attaching an annular stopper from above. Thus, high sealing performance can be maintained. This makes it possible to use a hard seal member adapted to a higher pressure fluid, further improving the functionality as a high-pressure trunnion type ball valve and ensuring high operability while reliably preventing fluid leakage. .

  According to the fourth aspect of the present invention, since the backup ring is disposed on both sides of the cap member, the seal member is protected from both sides even when the seat retainer slides with respect to the body body. The self-tightening force and sealing function of the member can be maintained over a long period of time.

  According to the invention which concerns on Claim 5, it can be set as a manual or an automatic type valve | bulb as needed, suitably according to the use condition of the valve, such as the magnitude | size and kind of the pressure of the high pressure fluid which flows through an inside, an installation location, etc. The operation method can be adopted.

It is sectional drawing which showed 1st Embodiment of the trunnion type ball valve in this invention. FIG. 2 is an enlarged cross-sectional view showing the vicinity of the seat retainer in FIG. 1. FIG. 2 is an enlarged cross-sectional view showing the vicinity of the stem in FIG. 1. It is the schematic diagram which showed the relationship between a handle cap and a cover. It is a partially omitted plan view of the body showing a state where the cover is removed. It is a partially expanded front view which shows the cover vicinity of FIG. It is sectional drawing which showed 2nd Embodiment of the trunnion type ball valve in this invention. FIG. 8 is an enlarged cross-sectional view showing the vicinity of the seat retainer in FIG. 7. FIG. 8 is a partially enlarged front view showing the vicinity of the cover of FIG. 7. It is principal part sectional drawing which showed 3rd Embodiment of the trunnion type ball valve in this invention. 5 is a graph showing the relationship between differential pressure and pressing force. It is a partially expanded sectional view which shows the conventional ball valve.

  Hereinafter, embodiments of a trunnion type ball valve according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a trunnion-type ball valve according to a first embodiment of the present invention, and FIG. 2 shows the vicinity of the seat retainer of FIG.

  In the figure, a ball valve body (hereinafter referred to as a valve body) 10 according to the present invention is particularly suitable for flowing a high-pressure fluid, and a ball (valve body) that is a valve body via a stem 11 in the body body. ) 12 is rotatably provided, and has a trunnion type ball valve structure in which sealing mechanisms 13 for sealing contact with the ball 12 are arranged at both side positions of the ball 12. The valve body 10 is composed of a body body 14, which is composed of a body 15 and cap members 16, 16 provided on the primary side and the secondary side of the body 15, respectively. 14 includes a seal mechanism 13. Here, the high pressure in the present embodiment is, for example, 35 MPa or more, and 70 to 105 MPa, specifically 90 MPa is assumed in the piping equipment for the hydrogen station.

  The body 15 is formed in a substantially rectangular shape, and the body body 14 is configured by screwing the cap members 16, 16 with the gasket 17 sandwiched between both sides of the body 15. A mounting hole 19 for mounting a later-described seat retainer 18 is provided on the inner peripheral surface of the cap member 16, and the seat retainer 18 is provided in the mounting hole 19 so as to be fitted therein. A mounting groove 21 for mounting a seal member 20 described later is formed in the mounting hole 19, and the mounting groove 21 is provided on the inner peripheral surface 14 a on the body main body 14 side located on the outer peripheral surface 18 a of the seat retainer 18. ing. Further, the mounting hole 19 is formed with a diameter expanding groove 23 for mounting a spring member 22 to be described later, which has a diameter larger than that of the mounting hole 19. Further, a female thread portion 24 is formed in communication with the other side of the mounting hole 19, and an external joint 26 can be screwed to the female thread portion 24. The cap member 16 can be integrated with the body 15 by a joining means such as adhesion or welding.

  The seal mechanism 13 includes a ball seat 25, the above-described seat retainer 18, a spring member 22, and a seal member 20. Among these, the ball sheet 25 is formed in an annular shape capable of sealing contact with the ball surface 12 a of the ball 12.

  The seat retainer 18 is provided to place and seal the ball seat 25 at a predetermined position on the ball 12, and has a diameter-expanded portion 26 disposed on the ball 12 side and a diameter smaller than the diameter-expanded portion 26. And a cylindrical portion 27. A groove portion 28 is formed at the tip of the enlarged diameter portion 26, and the ball sheet 25 is attached to the groove portion 28. An internal flow path 29 is formed in the seat retainer 18.

  As will be described later, the cylindrical portion 27 of the seat retainer 18 is formed in a straight shape with the same outer diameter by arranging the seal member 20 and the backup ring 30 on the body main body 14 side. Is inserted into the mounting groove 21 so that the seat retainer 18 is movable in the flow path direction. The sealing member 20 is in close contact with the outer peripheral surface of the cylindrical portion 27, and the cylindrical portion 27 is sealed by the sealing member 20 when the seat retainer 18 moves in the flow path direction.

  The spring member 22 is made of, for example, a coil spring, and is mounted between the expanded diameter groove portion 23 and the expanded diameter portion 26 of the seat retainer 18 fitted and inserted into the mounting hole 19, and the seat retainer 18 is supported by the spring member 22. Elasticity is applied to the ball seat 25 side. The spring member 22 may be a disc spring.

  The seal member 20 is made of, for example, a rubber O-ring, and is mounted in the mounting groove 21 together with the backup ring 30. Thus, the seal member 20 is disposed on the inner peripheral surface 14 a on the body main body 14 side, and the outer peripheral surface 18 a of the seat retainer 18. It is arranged. The backup ring 30 is made of, for example, PTFE (polytetrafluoroethylene). The seal member 20 and the backup ring 30 may be formed of different materials. In this case, it is preferable to use a soft material similar to rubber or PTFE, respectively, and by using a soft material. The mounting groove 21 is deformed to facilitate mounting. The seal member 20 is mounted in the mounting groove 21 with the backup rings 30, 30 arranged on both sides, and both sides are protected by the backup rings 30, 30.

  The ball 12 has a shaft portion 12 b on the upper side and a trunnion (lower stem) 12 c on the lower side, and the shaft portion 12 b and the lower stem 12 c are rotatably mounted in the body 15 via a bearing 31. When the ball 12 is rotated by the stem 11, the fluid can flow when the communication hole 12d formed in the ball and the internal flow path 29 of the seat retainer 18 communicate with each other.

  The valve body 10 exerts a pressing force by the seal mechanism 13 by the elastic force that the spring member 22 applies to the seat retainer 18 and the fluid pressure set on the inner diameter side of the seal member 20 by the above-described configuration. The high-pressure fluid can be sealed by the heavy seal method.

  On the outer peripheral side of the stem 11, a packing washer 33, a gland 34, a bush 35, and a ball bearing 36, in which a V packing 32 is accommodated, are disposed, and the stem 11 can be freely rotated into the body 15 through these. Installed.

  The packing washer 33 includes a cylindrical portion 37 that can store the laminated V-packing 32 that seals between the stem 11 and a bottom portion 38 on which the V-packing 32 is placed. V packings 32 are stacked in a suitable number. An annular groove 39 is formed on the outer peripheral side of the cylindrical portion 37, and a sealing O-ring 40 and a protective ring 41 are attached to the annular groove 39. A cutout groove 42 for guiding the leaked high-pressure fluid to the outside is provided on the upper surface side of the cylindrical portion 37. Similar to the packing washer 33, a sealing O-ring 40 and a protective ring 41 are mounted on the inner and outer circumferences of the V-packing 32 located on the bottom side. As described above, the seal O ring 40 and the protective ring 41 are mounted between the stem 11 and the V packing 32, the V packing 32 and the packing washer 33, and the packing washer 33 and the body 15. Leakage of high-pressure fluid from the shaft mounting portion is prevented.

  The packing washer 33 is disposed on the upper side of the stem 11 via the ball bearing 36, so that the stem 11 can rotate with respect to the V packing 32 and the ground 34 via the ball bearing 36. A leak port 43 is formed at a position facing the packing washer 33 of the body 15. Through this leak port 43, it becomes possible to detect a fluid leak by an external detection device (not shown).

  The gland 34 is formed in a substantially cylindrical shape, and has an annular flange portion 44 into which the packing washer 33 can be fitted, and a lid portion 45 that can cover the V packing 32. The gland 34 is attached from above the packing washer 33 so as to be fitted into a mounting recess 46 formed in the body 15, and presses the packing washer 33 containing the V packing 32 toward the ball bearing 36. A bush 35 is disposed on the inner peripheral side of the gland 34, and the V packing 32 is pressed against the bottom 38 of the packing washer 33 by the bush 35.

  With such a configuration, even when a high-pressure fluid flows in the valve body 10 and a force in the direction in which the stem 11 rises due to the differential pressure with the outside air in FIG. 1 is applied, the V-packing 32 is protected by the packing washer 33. Therefore, the V-packing 32 is prevented from being crushed in the axial direction, and the deterioration of the sealing performance is prevented, and the high-pressure fluid is surely prevented from leaking. For this reason, it is possible to prevent the V packing 32 from being consumed and to suppress the deterioration of the operability of the stem 11.

Further, a cover 50 shown in FIG. 6 is attached to the body 15 of the valve body 10, and a handle cap 51 and a manual handle 52 are attached via the cover 50.
The cover 50 is formed in a substantially disc shape, and a bottom surface side thereof is provided with a bowl-shaped side surface portion 54 that can be fitted to an annular protrusion 53 formed on the upper surface side of the body 15. 54, two counterbore portions 55 and two notches 56 are alternately formed at intervals of 90 °. A hole 57 for inserting the handle cap 51 is formed in the center of the cover 50, and a restriction piece 58 is formed projectingly in the hole 57 as shown in FIG. The rotation of the stem 11 can be restricted to 90 °.

As shown in FIG. 4, the handle cap 51 is formed in a substantially cylindrical shape having substantially the same diameter as the gland 34, and a locking piece 59 that can be locked to the regulating piece 58 of the cover 50 is formed on the outer peripheral side thereof. Has been. On the bottom surface side of the handle cap 51, a fitting hole portion 51a into which the parallel portion 11a formed on the upper end portion of the stem 11 can be fitted is formed. The handle cap 51 is connected to the fitting hole portion 51a and the parallel portion 11a. And the stem 11 are integrated. The handle cap 51 is formed with a substantially semicircular attachment hole 60, while the attachment portion of the handle 52 is provided in a substantially semicircular shape that can be fitted into the attachment hole 60.
Note that a female screw 61 is provided at a position where the side spot facing portion 55 and the cutout portion 56 of the annular projection 53 of the body 11 correspond to each other, and a fixing bolt 62 and a set screw 63 can be screwed to the female screw 61. It has become.

The handle cap 51 is attached to the stem 11 in a predetermined direction by fitting the fitting hole 51a and the parallel portion 11a. In this state, the cover 50 is fitted and attached to the annular protrusion 53 from above the handle cap 51. The Furthermore, the handle cap 51 is fixed by screwing the fixing bolt 62 and the set screw 63 to the female screw 61 via the counterbore portion 55 and the notch portion 56 of the cover 50, respectively. The handle cap 51 is fixed to the handle cap 51. And the handle 52 is attached to the stem upper end portion 11b. When the handle 52 is rotated, the locking piece 59 is regulated by contacting the regulating piece 58, so that the handle 52 can be opened and closed while the stem 11 is regulated to rotate at a rotation angle of 90 °.
In this manner, the manual handle 52 can be attached to the stem upper end portion 11b to make the valve body 10 a manual valve.

Then, the effect | action in the said embodiment of the trunnion type | mold ball valve of this invention is demonstrated.
Since the valve body 10 of the present invention sets the fluid pressure on the inner diameter side of the seal member 20 of the seal mechanism 13, the following self-tightening force can be obtained.

In FIG. 2, when the right side of the seat retainer 18 is the primary side and the left side is the secondary side, the ball seat 25 and the ball 12 are sealed at the position of the diameter d ₁ , and the self-tightening force (push by the ball seat) When the pressure) and F _1, the self緊力_{F 1 = 1/4 · π} (D 2 -d 1 2) a × [Delta] P _1. Here, D is the inner diameter of the sealing position in the seal member 20, and this inner diameter D coincides with the outer diameter of the cylindrical portion 27. ΔP ₁ represents a valve closing pressure difference (primary side pressure−secondary side pressure). In this embodiment, the relationship d ₁ <D <d ₂ is set.
On the other hand, when the left side of the seat retainer 18 is the primary side and the right side is the secondary side, the ball seat 25 and the ball 12 are sealed at the position of the diameter d ₂ , and the self-tightening force at this time is F _2. Tension F ₂ = ¼ · π (d ₂ ² −D ² ) × ΔP ₂ . Here, ΔP ₂ represents the valve cutoff differential pressure.
As described above, the pressure in the left or right direction is applied to the valve main body 10, and the valve main body 10 and the seat retainer 18 have the inner diameter D of the seal member 20 regardless of which of the left and right sides is the primary side or the secondary side. Seal at.

With this structure, the fluid pressure can be set by adjusting the self-tightening force even when the pressure in the left or right direction is applied only by changing the dimension of the inner diameter D of the seal member 20 with respect to the diameters d ₁ and d ₂ . At the same time, by reducing the difference between the diameters d ₁ and d ₂ and the inner diameter D to reduce the area where the self-tensioning force is applied, the small self-tensioning force is applied to obtain the optimum sheet pressing force by this self-tensioning force. Is possible.
Therefore, in the case of the double sealing method using the self-tightening force of the fluid and the elastic force of the spring member 22, the consumption of the sealing member 20 is suppressed and the decrease (fluctuation) of the self-tightening force is minimized. The pressing force of the sealing mechanism 13 due to the fluid pressure set on the inner diameter side of the sealing member 20 and the elastic force of the spring member 22 can be kept substantially constant to exhibit a stable sealing performance, and the torque performance during operation can be improved. It becomes possible to stabilize. For this reason, when the seat retainer 18 is provided, the load of the self-tightening force can be calculated based on the inner diameter of the seal member 20, so that the degree of freedom in design is increased.

  Further, by mounting the seal member 20 on the body main body 14 side, the inner diameter D is adjusted to obtain a necessary self-tightening force while maintaining a high sealing function by the seal member 20 without adversely affecting the seal performance. It is possible to withstand excessive stress without reducing the thickness of the cylindrical portion 27. As a result, the seat retainer 18 can be made compact while ensuring rigidity, and a high-performance trunnion-type ball valve can be provided while avoiding an increase in the size of the entire valve body 10.

Thus, since the cylindrical part 27 can be formed in a small diameter, the enlarged diameter part 26 does not become larger than necessary, and the diameter of the ball seat 25 attached to the enlarged diameter part 26 can be reduced. For this reason, it is possible to prevent the ball sheet 25 from being hugged or sucked to the ball 12, and the consumption of the seal member 20 can be suppressed.
Further, if the inner diameter is matched, the ball seat 25 having a larger outer diameter can be adopted, so that the degree of freedom in design is increased and the performance of the product can be improved.

  As a comparative example with the trunnion-type ball valve of the present invention, a technique is assumed in which the sealing mechanism is in sealing contact with the ball only by the elastic force of the spring member without exerting any self-tightening force. Since the uniformity of the sealing surface of the sealing member may decrease due to friction associated with the opening / closing operation of the valve, the degree shown in the present embodiment is such that the pressing force of the sealing mechanism increases as the fluid pressure increases. It is best to use the self-strength of

Here, the graph which compared the relationship between the differential pressure | voltage and the pressing force in the valve main body 10 of this invention and the ball valve of patent document 1 is shown in FIG. In this graph, for convenience of explanation, the pressing force by the spring in the trunnion type ball valve of the present invention is equivalent to that of the ball valve of Patent Document 1 in a state where the differential pressure is zero. When the pressing force of the ball seat (ball seat) is compared under the condition that the pressing force due to the elastic force of the spring member is the same, the ball valve of the literature 1 has the operating seal load due to the spring force and the flow path pressure load due to the fluid pressure. Therefore, when the differential pressure is 0, only the pressing force by the spring indicated by the two-dot chain line is applied. When the differential pressure increases from this state, the pressing force due to the fluid pressure indicated by the alternate long and short dash line (self-tightening force 2) increases greatly, and the slope of the graph also increases.
On the other hand, in the case of the valve main body of the present invention, since the pressing force of the ball seat 25 is mainly supported by the spring member 22, as shown by the solid line, the pressing force by the fluid pressure (self-tightening force) Rise (inclination of the graph) can be suppressed, and stable valve seat sealability can be ensured over a long period of time.

  FIG. 7 shows a second embodiment of the trunnion type ball valve according to the present invention, and FIG. 8 shows the vicinity of the seat retainer of FIG. In the following embodiments, the same parts as those in the above embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 8, in the valve main body 70 in this embodiment, a step portion 72 is formed on the inner peripheral surface of the cap member 71, and the engagement formed between the step portion 72, the body 73, and the cap member 71. An annular stopper 75 is provided between the portion 74. By mounting the annular stopper 75, a mounting groove 76 for mounting the seal member 20 is formed, and the seal member 20 is mounted in the mounting groove 76. At this time, as in the above-described embodiment, the backup member 30 is protected by the backup ring 30 by mounting the backup ring 30 on both sides of the seal member 20 that is an O-ring and mounting the backup ring 30 on the mounting groove 76. At this time, the spring member 22 is mounted in a resilient state between the annular stopper 75 and the enlarged diameter portion 26 of the seat retainer 18.

  By providing the detachable annular stopper 75 in the body main body 14 in this way, the seal member 20 and the backup ring 30 can be easily mounted at predetermined positions without being deformed from the opening side. Can be formed. For this reason, it becomes possible to further enhance the sealing function, and for example, it becomes easy to flow an ultrahigh pressure fluid exceeding 90 MPa.

  At that time, the annular stopper 75 is formed in a thin, substantially ring shape, and the mounting position of the cap member 71 screwed to the body 73 is adjusted to set the dimension of the engaging portion 74 in the flow path direction in advance. A gap G of about 0.5 mm, for example, can be formed between the body-side tip 75a of the annular stopper 75 and the body 73. Thus, by screwing the cap member 71 onto the body 73, a gap G is formed between the body 73 and the body-side tip 75 a of the annular stopper 75 and the body 73 so that the gasket 17 can be sandwiched between both parts. is doing.

  In this case, the distal end portion 75 a does not contact the body 73, and the annular stopper 75 is pressed against the cap member 71 side that is the mounting side of the seal member 20 and the backup ring 30 by the elastic force of the spring member 22. Installed. In this manner, the annular stopper 75 is pressed between the body 73 and the cap member 71 and the movement in the flow path direction is restricted, so that a gap is generated between the annular stopper 75 and the cap member 71. Is prevented, and high sealing performance by the seal member 20 is ensured.

  In the trunnion type ball valve of this embodiment, as shown in FIG. 7, a pneumatic actuator 80 for automatic operation is attached to the stem upper end portion 11b to form an automatic valve. Similarly to the manual handle 52 described above, the actuator 80 is also attached to the body 73 via the cover 76, the fixing bolt 62, and the set screw 63 shown in FIG. In this case, since the stem 11 is fitted and fixed in the fitting hole 83 formed in the output shaft 82 of the pneumatic actuator 80, it is not necessary to use a handle cap.

  This actuator 80 is a so-called spring return type, and is provided with a retainer member 85 for preventing the spring member 84 mounted therein from popping out. The retainer member 85 is formed with a projecting abutting portion 86, and when the piston 87 reciprocates in the cylinder 88, the abutting portion 86 abuts on both sides inside the cylinder 88, whereby the piston 87 is illustrated. The stroke not to be controlled is regulated, and the rotation angle of the output shaft 82 is regulated to a predetermined angle, that is, 90 °.

  FIG. 10 shows a third embodiment of a trunnion type ball valve according to the present invention. In the valve main body 90 in this embodiment, the annular stopper 91 is formed in a cylindrical shape, the annular stopper 91 is provided between the step portion 92 and the engaging portion 93, and the body-side distal end portion 91 a of the annular stopper 91 and the body are provided. 94 is provided with a gap G ′. Also in this case, as in the case of FIG. 7, the gap G ′ is set to a predetermined dimension by adjusting the mounting position of the cap member 95 with respect to the body 94 in advance, and the seal member 20 and the backup ring 30 are deformed. The annular stopper 91 can be assembled from above by simply mounting the cap member 95 from the opening side.

  The present invention is particularly suitable for piping equipment through which hydrogen or the like of a high-pressure fluid used in a fuel cell flows, but can exhibit excellent sealing properties and torque characteristics if the high-pressure fluid flows through a pipeline, for example, It is suitable as a high pressure ball valve used in a place where various high pressure fluids flow such as a valve in a CNG (Compressed Natural Gas) station or a pipe valve.

DESCRIPTION OF SYMBOLS 10 Valve main body 11 Stem 12 Ball 12a Ball surface 13 Seal mechanism 14 Body main body 14a Inner peripheral surface 15 Body 16 Cap member 18 Seat retainer 20 Seal member 21 Mounting groove 22 Spring member 22a Outer peripheral surface 25 Ball seat 30 Backup ring 52 Manual handle 72 Step part 74 Engagement part 75 Annular stopper 76 Mounting groove 80 Pneumatic actuator

Claims (5)

  A trunnion-type ball valve in which a ball is rotatably provided in a body body through a stem, and seal mechanisms for sealing contact of the ball are arranged at both side positions of the ball. The seal mechanism includes a ball surface and a seal. Located on the outer peripheral surface of the seat retainer, a ball retainer that is in contact, a seat retainer with the ball seat attached to the tip, a spring member attached to the seat retainer to impart a resilient force to the ball seat side It consists of a seal member mounted in a mounting groove on the inner peripheral surface of the body body side, and the spring mechanism pushes the seal mechanism by the elastic force applied to the seat retainer and the fluid pressure set on the inner diameter side of the seal member. A trunnion-type ball valve characterized by pressure.   2. The trunnion type ball valve according to claim 1, wherein the body body is provided with a cap member on each of a primary side and a secondary side of the body, and a mounting groove for mounting a seal member is formed on an inner peripheral surface of the cap member.   The trunnion according to claim 1 or 2, wherein a mounting groove for mounting a seal member is formed by a step formed on the inner peripheral surface of the cap member and an annular stopper provided between the engagement portion of the body and the cap member. Type ball valve.   The trunnion-type ball valve according to claim 3, wherein the seal member is an O-ring, and an O-ring having backup rings on both sides is mounted in the mounting groove.   The trunnion-type ball valve according to any one of claims 1 to 4, wherein a manual handle or an actuator is attached to an upper end portion of the stem to form a manual or automatic valve.

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