JP2016014468A - High-pressure pipe joint and high-pressure valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-pressure pipe joint and a high-pressure valve suitable for a high-pressure fluid flow passage, capable of exhibiting high sealability and ensuring the prevention of the leakage of an extra-high pressure fluid while preventing deformation and breaking of a gasket and connection end portions due to an excessive fastening force and improving durability, and facilitating pipe installation.SOLUTION: Connection end portion surfaces 15 of a pair of tubular connection members 10 are sealed and connected by fastening a screw member 12 via a gasket 11, the gasket 11 is formed of a metal lower in hardness than the connection end portion surfaces 15, a narrow flat seal portion 20 is formed on an innermost side or near the innermost side of each connection end portion surface 15, an obtuse tapered surface 21 is formed along an outside diameter of the narrow flat seal portion 20, the connection end portion surfaces 15 are sealed in a state of widening a seal portion 22 sealed to the gasket 11 by the narrow flat seal portion 20 and the obtuse tapered surface 21 by a magnitude of a fastening load at a time of fastening the screw member 12, and sealability is maintained even against an extra-high pressure fluid by a seal structure in which the obtuse tapered surface 21 on the outside diameter of the narrow flat seal portion 20 acts as a stopper at a time of fastening the screw member 12 at a maximum fastening load.

Description

  The present invention relates to a high-pressure pipe joint, for example, a super-high pressure pipe joint and a high-pressure valve that can be applied to a flow path of a hydrogen station through which an ultra-high pressure fluid such as hydrogen flows.

  In recent years, for example, the supply infrastructure of a hydrogen station of an automobile fuel cell is becoming widespread, and high-pressure hydrogen that reaches an ultra-high pressure of about 99 MPa may flow in the piping equipment of this hydrogen station. For this reason, the high-pressure pipe joint is desired to have a performance that can withstand a high-pressure fluid called this type of super-high-pressure fluid.

As a pipe joint for high-pressure fluid, for example, a pipe joint disclosed in Patent Document 1 is disclosed. In this pipe joint, in one set of joint members, an annular projection having a semicircular cross section is formed on each butt end surface, and a metal gasket is interposed between the butt end surfaces to screw a male screw or a female screw member. The tips of these protrusions are provided so as to press and seal both sides of the gasket.
In the pipe joint of patent document 2, the annular protrusion for gasket pressing is formed in the inner peripheral part of each butt | matching end surface of the joint member of both sides, respectively. The cross-sectional shape of these gasket-pressing annular protrusions is a sector of about a quarter of a circle, and the inner peripheral surface of each joint member including these inner peripheral surfaces is formed into a tapered surface that spreads toward the tip side. Yes. This pipe joint is formed so that the over-tightening prevention annular protrusion protrudes in the tightening direction from the gasket-pressing annular protrusion, and a retainer for holding the gasket on the joint member during tightening is provided so that it can be pressed from both sides. It has been.
In FIG. 12, the conventional pipe joint 1 used for the hydrogen station for ultra-high pressures of about 99 MPa is shown. This pipe joint 1 has a convex tapered surface 3 for sealing formed at the tip of the piping tube 2, and a sealing collar 5 is provided on the inner periphery of the male screw nut 4 for mounting the piping tube 2. A concave taper surface 7 is formed on the inner side of the female screw body 6 that is the attachment side, and the convex taper surface 3 can be contacted and sealed. In this pipe joint, the pipe tube 2 is connected to the female screw through the male screw nut 4 and the collar 5 by screwing the male screw 8 formed on the outer periphery of the male screw nut 4 and the female screw 9 formed on the inner periphery of the female screw body 6. Connected to body 6.

When these pipe joints are tightened, the tightening load is determined by JISB8266 Appendix 3 “Bolt tightening flange of pressure vessel”. In this case, as the tightening load, A. Bolt load required in use, B. There is a bolt load required when tightening the gasket. For example, assuming that the operating temperature is normal temperature, the material strength is the same, so the tightening load of the pipe joint must be tightened with a larger load than these. is there.
Among the tightening loads, A. The bolt load Wm1 required in use is expressed by the sum (Wml = H + Hp) of the total load H applied by the internal pressure and the compressive force Hp applied to the gasket or joint contact surface in order to maintain sufficient airtightness. At this time, the total load applied by the internal pressure H = π × G ^ 2 × P / 4, the compressive force Hp = 2 × π × b × G × m × P applied to the gasket or joint contact surface in order to maintain sufficient airtightness P: internal pressure, G: diameter of the gasket reaction force circle, b: basic width of the gasket seat, m: gasket coefficient, and thread material strength at operating temperature: σb.
On the other hand, B. The bolt load Wm2 required at the time of tightening the gasket is expressed by Wm2 = π × b × G × y, where y is the minimum design tightening pressure of the gasket and the thread material strength at normal temperature is evaluated by σa.

By the way, in the gasket-clamping type pipe joint as described above, there may be a case where a projection other than the annular projection for sealing is provided at the gasket clamping position.
For example, in the pipe joint of Patent Document 3, a bead that contributes to sealing of the gasket is provided as an inner ring on the ground end face of the joint member, and a rim is provided as an outer ring on the outer peripheral side of the bead. In this case, the bead is formed in an arch shape and the rim is formed in a substantially trapezoidal shape, an annular flat area is formed between them, and a notch-like recess is formed in the rim. In this pipe joint, when the joint members are tightened together, the gasket is inserted into the area or the recess of the gasket to prevent the pipe joints from slipping or twisting in the circumferential direction. Trying to prevent the relative rotation of.

  In the tube coupling of Patent Document 4, in addition to each bead for sandwiching a gasket formed on the joint member, a protrusion is provided on the end face side of the joint member on both sides of the gasket.

Japanese Utility Model Publication 1-228398 Japanese Patent No. 3567786 JP 2001-516862 A US Pat. No. 5,145,219

In tightening the pipe joint of Patent Document 1 described above, A. The bolt load Wm1 required in use is squared by the diameter G of the gasket reaction force circle. The calculated bolt load Wm1 required in use is B. The bolt load Wm2 required at the time of tightening the gasket is relatively larger than the value. As a result, A. The required bolt load Wm1 is required in use, but in this case, the absolute value of the tightening load becomes large because the diameter G of the reaction force circle of the gasket is larger than the inner diameter of the pipe.
And when the pipe joint screw is tightened by this tightening load, the tightening force becomes excessive because the bead width for sealing the pipe joint is narrow and there is no stopper mechanism at the time of tightening. In addition, the allowable surface pressure limit of the material constituting the sealing bead may be exceeded, and the gasket or the sealing bead may be greatly deformed or broken to prevent the surface pressure from being secured. For this reason, there is a problem that the fluid easily leaks and the durability of the seal portion is deteriorated. Further, the gasket may protrude to the inner diameter side and adversely affect the fluid.

In the case of the pipe joint of Patent Document 2, a sealing bead is formed on the innermost diameter side of the pipe, and the gasket surface and the flange of the sleeve serve as a stopper. Even when the bolt is over-tightened with a tightening load that is more than the bolt load Wm2 required for tightening the gasket, abnormal deformation and breakage of the sealing bead and the gasket can be prevented by the stopper function of the gasket surface and the flange of the stopper. However, as a result, A.I. Sealing is performed via the sealing bead with a load smaller than the bolt load Wm1 required in use, and the gasket is pressed by the entire sealing bead, so creeping is applied to the partially pressed portion of the gasket. A phenomenon will occur. In this case, there is a problem that stress applied to the gasket is relaxed due to elongation deformation due to a creep phenomenon, the seal surface pressure is lowered, and leakage is likely to occur.
Furthermore, even if you try to tighten the nuts again to recover such seal surface pressure, there is a collar for preventing over-tightening, or pressing the gasket over the entire surface of the butt end face will result in a sufficient increase. I can't tighten it.
For these reasons, the pipe joints of Patent Document 1 and Patent Document 2 are limited to, for example, a pressure fluid of about 26 MPa, that is, a so-called medium pressure fluid seal, and used as a pipe joint for an ultrahigh pressure fluid of about 99 MPa. Not suitable for.

  In the case of the pipe joint in FIG. 12, it is possible to flow an ultra-high pressure fluid, but the pipe tube 2 to be connected is deeply inserted into the body side via the male screw nut 4 and sealed, so that the pipe tube 2 It is necessary to securely insert the convex taper surface 3 to the back side of the female thread body 6 and to tighten and connect the nut 4 while maintaining the state in contact with the concave taper surface 7. There is a problem that it is difficult.

  On the other hand, in the pipe joint of Patent Document 3, since the gasket is brought into contact with the bead, the rim, the area, and the dent to prevent the rotation, the contact area of the gasket with respect to the joint member is increased. In the pipe joint having this structure, it is difficult to locally seal the gasket with the joint member, and there is a possibility that sufficient sealing performance cannot be secured for high-pressure fluid such as ultrahigh-pressure fluid.

  In Patent Document 4, when the protrusions provided on both surfaces of the gasket are brought into contact with the end faces of the joint member to prevent rotation, the pinching pressure is applied to the peripheral surface by intermittently forming the protrusions at predetermined intervals. It becomes difficult to work evenly in the direction, and excessive tightening force may cause rotation and damage the gasket. Further, when the force is concentrated on the protrusion, the protrusion is easily damaged, and there is a problem that the protrusion needs to be formed on the gasket.

  The present invention has been developed to solve the above-mentioned problems, and its object is a pipe joint suitable for a flow path of high-pressure fluid, and a gasket or connection end side due to excessive tightening force. Providing a high-pressure pipe joint and a high-pressure valve that can prevent deformation and breakage of the pipe, exhibit high sealing performance while improving durability, reliably prevent leakage of ultra-high pressure fluid, and make piping work easy It is in.

  In order to achieve the above object, the invention according to claim 1 is a high-pressure pipe joint in which the connection end surfaces of a pair of tubular connection members are sealed and connected by tightening a screw member via a gasket, The metal is lower in hardness than the connection end surface, and the connection end surface is formed with a narrow flat seal portion in the innermost side or near the innermost side, and an obtuse angle along the outer diameter side of the narrow flat seal portion. When the taper surface is formed and the screw member is tightened, the seal is expanded with the narrow flat seal portion and the obtuse angle taper surface depending on the size of the tightening load, and at the maximum tightening load. When tightened, this is a high-pressure pipe joint that maintains a sealing property against ultra-high pressure fluid with a seal structure in which an obtuse taper surface on the outer diameter side serves as a stopper.

  The invention according to claim 2 is the high-pressure pipe joint in which a relief portion having no stopper structure is provided on the outer diameter side of the obtuse angle tapered surface.

  The invention according to claim 3 is a high-pressure pipe joint in which chamfering is provided on the flow path side of the connection end surface of the tubular connection member, and the narrow flat seal portion is prevented from being deformed to the flow path side.

  The invention according to claim 4 is the high-pressure pipe joint in which the outer diameter of the gasket is provided so as to be fitted to the inner diameter of the female nut constituting the screw member, and this gasket is positioned in the female nut in a centered state.

  The invention according to claim 5 is a high-pressure pipe joint in which the connection end surface of a pair of tubular connection members is sealed and connected by tightening a screw member via a gasket, and the gasket is harder than the connection end surface. Is a low metal, and an annular protrusion is formed in the vicinity of the inner diameter of the connection end surface. On the outer diameter side of the connection end surface, a screw member is tightened to prevent the tubular connection member from rotating in the circumferential direction. This is a high-pressure pipe joint provided with an outer peripheral annular portion.

  The invention according to claim 6 is the high-pressure pipe joint in which the clamping surface between the outer peripheral annular portion and the annular projection is a flat surface.

  The invention according to claim 7 is a high-pressure pipe joint having a concave flat surface between the outer peripheral annular portion and the annular projection.

  The invention according to claim 8 is the high-pressure pipe joint in which the outer peripheral annular portion is provided with a slit for releasing the pressure in the concave flat surface.

  The invention according to claim 9 is the high-pressure valve in which the high-pressure pipe joint is provided on the connection portion side of the valve body.

  According to the first aspect of the present invention, an excessive tightening force can be obtained by sealing while expanding the seal portion with the gasket according to the size of the tightening load by the narrow flat seal portion and the obtuse angle tapered surface of the connection end surface. In the case of the occurrence of an overload, the gasket is sealed from the narrow flat seal part to the obtuse angle taper surface, so that an excessive tightening load is not applied to the narrow flat seal part. Durability can be improved while preventing side deformation and breakage. The full load of the thrust at the time of tightening is applied to the narrow flat seal portion to exhibit high sealing performance by surface pressure, and leakage can be prevented even with an ultrahigh pressure fluid such as high pressure hydrogen of about 99 MPa. In addition, vibration is less likely to loosen due to the reaction force due to the maximum tightening load, and the surface pressure increases as the tightening force increases, so that additional tightening can be handled. Even if the stress applied to the gasket is eased by the creep phenomenon and the seal surface pressure is lowered, the seal surface pressure can be recovered by this tightening.

  According to the second aspect of the present invention, when the tightening load becomes large and the gasket is going to deform in the outer diameter direction, the tightening load on the outer diameter side gasket is stopped by the relief portion, so that the gasket or narrowness is reduced. Deformation of the flat seal portion and the obtuse angle tapered surface can be prevented. For this reason, durability of a gasket can be improved and a high sealing performance can be maintained.

  According to the third aspect of the present invention, the chamfering prevents the narrow flat seal portion from being deformed to the flow path side to maintain the sealing performance, and suppresses the deformation of the gasket to the flow path side, thereby affecting the fluid by the gasket. Can be minimized.

  According to the invention which concerns on Claim 4, it becomes possible to mount | wear easily, centering a gasket, without requiring the retainer for attachment or detachment. In this case, the gasket is prevented from being deformed by sealing the gasket with the narrow flat seal portion and the obtuse angle taper surface, and the gasket is not attached to the connection end surface and can be easily removed.

  According to the invention of claim 5, the circumferential annular portion prevents slippage or twist in the circumferential direction between the gaskets sandwiched between the tubular connection members, and prevents the circulation of the tubular connection members. Can be connected. Sealing while preventing rotation in this way can prevent the occurrence of sliding grooves and damage to the gasket, improve durability, and improve sealing performance. Leakage is reliably prevented even when high-pressure fluid flows. Furthermore, the tightness of the gasket by the annular protrusions can be improved and the sealing performance can be recovered while preventing the tubular connecting member from rotating around the outer peripheral annular portion by retightening. The peripheral annular portion relieves stress at the time of sealing the annular protrusion, and exhibits a uniform sealing force.

  According to the sixth aspect of the present invention, the tubular connecting member is rotated by the outer peripheral annular portion while the surface pressure is increased by the flat clamping surface to improve the sealing performance by the annular protrusion and prevent fluid leakage. By blocking it, it is possible to prevent the gasket from being slid or to be damaged, and maintain the sealing performance.

  According to the invention according to claim 7, the tubular connecting member is connected in a state where the gasket is locally contacted by the small contact area of the outer peripheral annular groove and the annular protrusion, and thereby the pressing force between the contact parts is reduced. Improves to exhibit sufficient sealing performance against ultra high pressure fluid to prevent leakage.

  According to the eighth aspect of the present invention, the internal pressure on the concave flat surface side is released to the outside by the slit, and the annular protrusion and the outer peripheral annular portion are uniformly pressed and sealed in a stable state to improve the sealing performance while preventing the rotation. it can.

  According to the ninth aspect of the invention, it is possible to open and close the flow path through which the super-high pressure fluid flows, and to control the flow rate. For example, when applied to a flow path such as a hydrogen station through which high-pressure hydrogen flows, Can be controlled at a large flow rate while preventing leakage.

It is the longitudinal cross-sectional view which showed embodiment of the high-pressure piping joint in this invention. FIG. 2 is an enlarged longitudinal sectional view showing a main part of FIG. 1. It is a partially expanded sectional view which shows the state which fastened the screw member of FIG. It is the schematic which shows a gasket retainer. It is the longitudinal cross-sectional view which showed other embodiment of the high-pressure piping joint in this invention. It is the longitudinal cross-sectional view which showed other embodiment of the piping joint for high pressures. It is a partially expanded sectional view of the high-pressure piping joint of FIG. It is an expanded sectional view which shows the connection end part surface vicinity of the pipe connection member of FIG. It is a partially cutaway side view of the tubular connection member of FIG. It is a graph which shows the relationship between a fastening torque and a rotation angle. It is the longitudinal cross-sectional view which showed an example of the valve | bulb for high pressures. It is sectional drawing which shows the conventional pipe joint.

  Hereinafter, embodiments of a high-pressure pipe joint according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of a high-pressure pipe joint according to the present invention, and FIGS. 2 and 3 show enlarged views of main parts of the high-pressure pipe joint. As shown in FIG. 1, the high-pressure pipe joint in the present invention includes a tubular connecting member 10, a gasket 11, and a screw member 12. The nominal diameter of the joint is, for example, from 1/4 inch to 9/16 inch, and each figure shows an embodiment of 3/8 inch.

  In FIG. 1, the tubular connection member 10 is formed in a substantially cylindrical shape using, for example, high-strength austenitic stainless steel such as SUS316, and a connection end surface 15 is formed on the connection side. The connection end surface 15 of the pair of tubular connection members 10 is provided so as to be connected while being sealed by tightening the screw member 12 via the gasket 11. The screw member 12 is formed, for example, in the form of a male screw member 16 and a female nut 17 using a stainless alloy or the like as a material, and these are provided so as to be screwed together. An annular flange 18 formed on the end side of the tubular connecting member 10 is accommodated inside the screw member 12, and the annular flange 18 of one tubular connecting member 10 is formed on the inner periphery of the female nut 17. It is locked to the annular projection 19 and is provided so that it can be tightened when the end of the annular flange 18 of the other tubular connecting member 10 is pressed against the end of the male screw member 16.

  A narrow planar seal portion 20 is formed on the connection end surface 15 in the vicinity of the innermost side, and an obtuse angle is formed with respect to the planar seal portion 20 along the outer diameter side of the narrow planar seal portion 20. An obtuse angle taper surface 21 is provided. 2 and 3, the narrow planar seal portion 20 in the present embodiment is provided in a position near the innermost side of the connection end surface 15, for example, in an annular shape having a width L of 0.2 to 0.6 mm in the radial direction, An obtuse taper surface 21 is formed from the narrow flat seal portion 20 at an inclination angle θ of 2 to 6 °.

In this case, if the width L of the narrow flat seal portion 20 is less than 0.2 mm, the narrow flat seal portion 20 comes into line contact with the gasket 11, and the gasket 11 may be damaged due to the one pole concentration of the load.
On the other hand, if the width L exceeds 0.6 mm, the seal surface pressure of the gasket 11 obtained when the screw member 12 is tightened is lowered, and the sealing performance against the ultrahigh pressure fluid may be lowered. Therefore, the width L is preferably 0.2 to 0.6 mm.

If the inclination angle θ of the obtuse angle tapered surface 21 is less than 2 °, the gasket 11 may be in contact with the entire obtuse angle tapered surface 21.
In addition, when the inclination angle θ exceeds 6 °, the width of the seal portion with the gasket 11 increases with an increase in tightening load, and the gasket 11 may be damaged due to the concentration of the load.

The pair of tubular connecting members 10 are connected by tightening the screw member 12 in a state where the gasket 11 is sandwiched on the connection end surface 15 side, and when the screw member 12 is tightened, the pair of tubular connecting members 10 is narrowed depending on the size of the tightening load. The flat seal portion 20 and the obtuse angle tapered surface 21 seal the seal portion 22 with the gasket 11 in an expanded surface seal state. In this case, when the tubular connecting member 10 is tightened with the maximum tightening load, the obtuse taper surface 21 on the outer diameter side functions as a stopper so that the contact area between the gasket 11 and the obtuse angle taper surface 21 does not expand. It has a sealing structure. In other words, the gasket 11 is formed in a seal structure in which a tightening load is applied to a portion in contact with the obtuse angle tapered surface 21 and no load is applied to a portion not in contact with the obtuse angle tapered surface 22. .
Specifically, the obtuse angle tapered surface 21 has a stopper function that stops the deformation of the gasket 11 in the middle of the obtuse angle tapered surface 21, and the obtuse angle tapered surface 21 on the outer diameter side of the position where the stopper function has worked has a gasket. A space in which 11 does not contact the obtuse angle tapered surface 21 is secured.

With the above configuration, when the tubular connecting member 10 is tightened with the maximum tightening load, the sealing performance against the ultrahigh pressure fluid is ensured in the portion where the gasket 11 and the obtuse angle tapered surface 21 abut.
And, by securing the space between the obtuse angle tapered surface 21 and the gasket 11 on the outer diameter side from the position where the stopper function works, the tubular connecting member 10 can be gradually tightened and tightened. It is possible to increase the sealing performance against the ultra-high pressure fluid.

  Here, the ultra-high pressure fluid refers to a pressure fluid of about 99 MPa, and an example thereof is fuel hydrogen used in a hydrogen station of an automobile fuel cell. In the high-pressure pipe joint of the present invention, for example, a fluid having a pressure from a low-pressure fluid of about 5 MPa to such an ultrahigh-pressure fluid can be flowed.

  Further, as shown in FIGS. 2 and 3, a relief portion 25 having no stopper function is provided on the outer diameter side of the obtuse angle tapered surface 21. In this embodiment, the relief portion 25 is formed in a flat surface shape parallel to the narrow planar seal portion 20 from the outermost diameter side of the obtuse angle tapered surface 21. Thereby, the separation distance between the relief portions 25 becomes longer than the separation distance between the stopper positions (contact boundary between the gasket 11 and the obtuse angle taper surface 21) in the obtuse angle tapered surface 21. 11 is reliably prevented. For this reason, the gasket 11 is not sandwiched between the connection end surface 15 and the gasket 11 in the escape portion 25, and deformation of the gasket 11 to the outer diameter side is allowed.

  A chamfer 26 is provided on the flow path side of the connection end surface 15 of the tubular connection member 10. The chamfer 26 is provided with a width of about 0.5 mm at an angle of 10 to 45 °. By providing the chamfer 26 in this way, the chamfer 26 is chamfered on the innermost side in the case of the high-pressure pipe joint of this embodiment. 26, a narrow flat seal portion 20 is formed near the innermost side on the outer diameter side of the chamfer 26. When the chamfer 26 is provided, the chamfer 26 prevents the innermost pinching of the tubular connecting member 10, thereby preventing the narrow flat seal portion 20 from being deformed to the flow path side. In addition, the narrow plane seal part 20 should just be formed in the innermost side of the connection end part surface 15, or innermost vicinity.

  The gasket 11 is formed in a ring shape from a metal having a hardness lower than that of the connection end face 15, and is made of, for example, nickel, stainless steel, copper such as C1020, or a copper alloy. The inner diameter of the gasket 11 is the same as or slightly larger than the flow path, and the outer diameter of the gasket 11 is slightly smaller than the inner peripheral side of the female nut 17. The outer diameter of the gasket 11 may be approximately the same as the inner diameter of the female nut 17. In the present embodiment, the thickness of the gasket 11 is set to about 0.8 mm.

  As shown in FIGS. 1 to 3, a gasket retainer 30 is attached to the outer peripheral side of the gasket 11, and the gasket 11 can be attached to and detached from the connection end surface 15 via the gasket retainer 30. An annular protrusion 31 is formed on the outer periphery of the gasket retainer 30, and the inner diameter of the annular protrusion 31 is slightly smaller than the outer diameter of the gasket 11. Thereby, the gasket 11 can be attached to the inner periphery of the annular protrusion 31 in a fitted state. As shown in the perspective view of FIG. 4A and the longitudinal sectional view of FIG. 4B, the annular protrusion 31 is formed with a plurality of elastic locking portions 32 at predetermined intervals, as shown in FIGS. Further, the gasket retainer 30 to which the gasket 11 is attached is provided on the outer peripheral side of the connection end face 15 by the elastic force of the elastic locking portion 32 in the inner peripheral direction. The gasket 11 can be removed by removing the elastic locking portion 32 from the connection end surface 15.

  Notches 33 having an appropriate shape, size, and number are formed on the outer periphery of the gasket 11, and the type of the gasket 11 can be identified by visually checking the notches 33. Thereby, the gasket 11 having a diameter suitable for the connection end surface 15 can be mounted on the gasket retainer 30 and attached. In the present embodiment, the notch 33 is provided for identification. However, as long as the sealing function as a gasket can be exhibited, different types of identification parts such as protrusions may be provided.

It is also possible to form the tubular connecting member 10 described above from a material having a hardness higher than that of SUS316, and to form the gasket 11 from SUS316. Further, the relief portion 25 may be in a form other than a flat surface parallel to the narrow flat seal portion 20 as long as it does not become a stopper without contacting the gasket 11. For example, the relief portion may be an obtuse angle tapered surface 21. It can also be formed in a taper shape extending from.
Moreover, as a use in the case of using said high-pressure pipe joint as a joint, besides an ordinary straight pipe, for example, an elbow pipe, a cheese pipe, etc. are mentioned, In addition, it is used for various connection parts. it can.

Then, the effect | action in the said embodiment of the high-pressure piping joint of this invention is demonstrated.
In the high-pressure pipe joint of the present invention, the gasket 11 is formed of a metal having a hardness lower than that of the connection end surface 15, the narrow flat seal portion 20 is formed in the vicinity of the innermost side of the connection end surface 15, and the narrow flat surface An obtuse angle taper surface 21 is formed along the outer diameter side of the seal portion 20, and when the screw member 12 is tightened, the narrow planar seal portion 20 and the obtuse angle taper surface 21 correspond to the size of the tightening load. Sealing is performed in a state where the sealing portion 22 with the gasket 11 is expanded.

  In this case, when the screw member 12 is tightened, first, as shown in FIG. 2, the narrow flat seal portion 20 which is a seal surface comes into contact with the gasket 11 with the seal width W1 of the width L, and further tightened. The obtuse angle taper surface 21 formed along the outer diameter side of the flat seal part 20 causes the gasket 11 to gradually deform in the axial direction along the obtuse angle taper surface 21 so that the seal part 22 is the seal shown in FIG. Expands to width W2. As a result, the bolt load Wm2 required at the time of gasket tightening described above and the bolt load Wm1 required in the state of use can be tightened by a tightening force, and the tightening acting on the tubular connecting member 10 can be performed. It becomes possible to act on the obtuse angle tapered surface 21 side with the narrow flat seal portion 20 as the center by using the total load as the seal load. For this reason, the tightening load can be increased to increase the seal load.

  Even when tightened by the maximum tightening load, the obtuse angle tapered surface 21 serves as a stopper, and no tightening force is applied to the gasket 11 portion that is not in contact with the obtuse angle tapered surface 21. 11 is prevented from being deformed in the radial direction or breaking due to the concentration of the load, while the full load of the screw tightening thrust is received by the seal portion 22 to maintain high sealing performance even in the case of an ultra-high pressure fluid, and the temperature change Even against the occurrence of vibration and vibration, it is possible to obtain characteristics that are less likely to loosen due to the reaction force due to the maximum tightening load. In particular, since the sealing performance is ensured by the parallel sealing surfaces formed by the narrow flat seal portions 20, the function of increasing the surface pressure with high efficiency at the time of tightening is exhibited and it is possible to cope with additional tightening. At the time of this tightening, the gasket 11 is sealed while being in contact with the narrow planar seal portion 20 and the obtuse angle tapered surface 21 while recovering the sealing force by the narrow planar seal portion 20, so that the gasket 11 is not deformed or broken. It is prevented.

At this time, as described above, if the width L in the radial direction of the narrow planar seal portion 20 is 0.2 to 0.6 mm, the local deformation becomes excessive by setting the width L to 0.2 mm or more. The surface pressure required for sealing can be secured by setting the thickness to 0.6 mm or less. Furthermore, if the inclination angle θ of the obtuse taper surface 21 is in the range of 2 to 6 °, the surface pressure is improved by gradually deforming the narrow flat seal portion 20 into a flat shape when tightened with the maximum tightening load. High sealing performance can be exhibited, the stopper function can be surely exhibited while preventing leakage, and deformation and breakage of the gasket 11 due to excessive tightening can be prevented. Since the gasket 11 does not come into contact with the entire surface of the obtuse angle tapered surface 21, the gasket 11 does not stick to the connection end surface, and there is no possibility that the gasket 11 is damaged during replacement or maintenance.
Since the amount of deformation of the gasket 11 in the axial direction by the obtuse angled taper surface 21 can be suppressed to about 0.2 to 0.3 mm on the front and back of the seal portion 22, the tubular connecting member of equipment or the like without moving the joint or pipe 10 can be easily attached and detached.

On the other hand, even if the connection end surface is provided so that the seal portions are parallel to each other and the seal width is the same as the seal width W2 by the narrow flat seal portion and the obtuse angle tapered surface, Since there is no margin, the sealing performance will not be exhibited reliably. In addition, in this case, the diameter of the gasket reaction force circle becomes an intermediate position of the seal width and the value thereof becomes large, so that there is a problem that the pressure receiving area increases and the seal load increases.
According to the high-pressure piping joint of the present invention, the screw member 8 is maintained while maintaining the state in which the tapered surface 3 of the piping tube 2 and the tapered surface 3 of the body 6 are in contact with each other as in the prior art of FIG. , 9 is not necessary to be tightened and connected, so piping construction is easy.

  Further, by mounting the gasket retainer 30 on the outer peripheral side of the gasket 11, the gasket 11 can be easily attached to and detached from the tubular connecting member 10 through the gasket retainer 30, and the entire joint can be easily assembled. Become. By providing the notch 33 for identification in the gasket retainer 30, it is possible to reliably prevent leakage by attaching the gasket 11 having an appropriate diameter according to the pipe diameter or the like.

FIG. 5 shows another embodiment of the high-pressure pipe joint of the present invention. 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.
In this embodiment, the gasket 40 is provided with an outer diameter that can be fitted to the inner diameter of the female nut 17 constituting the screw member 12. In this case, the gasket 40 can be easily mounted while holding the gasket 40 on the inner diameter side of the female nut 17 without using the gasket retainer 30, and the gasket 40 is positioned in the female nut 17 in a centered state after mounting. Is done. Furthermore, since the deformation amount on the outer diameter side and inner diameter side of the gasket 40 is reduced, the gasket 40 can be easily detached from the female nut 17 without sticking to the tubular connecting member 10.

  FIG. 6 shows still another embodiment of the high-pressure pipe joint. Here, in the high-pressure pipe joint as shown in the figure, when the female nut 17 of the screw member 12 is tightened, the locking surface 19a of the protrusion 19 is pressed against the opposing surface 18a of the annular flange 18 of the tubular connecting member 70, The connection is made while the female nut 17 and the tubular connecting member 70 are rotated. In this case, the locking surface 19a may be formed in a tapered shape toward the inner diameter side at an angle of about 1 °, for example.

  When the tubular connecting member 70 is connected by the rotation of the female nut 17 as described above, if the gasket 11 is sandwiched with the tubular connecting members 70 being rotated, a groove or damage due to sliding contact occurs on the gasket 11. It may lead to a decrease in sealing performance. For this reason, in order to improve the sealing performance by the gasket 11 when connected by the tubular connecting member 70, it is important to prevent the tubular connecting member 70 from being rotated simultaneously with the sandwiching of the gasket 11.

  In order to solve this problem, in the high-pressure pipe joint of this embodiment, as shown in FIGS. 6 to 8, an annular ring portion that is a narrow flat seal portion is provided near the inner diameter of the connection end surface 15 of the tubular connection member 70. A protrusion 72 is formed, and an outer peripheral annular portion 73 is provided on the outer diameter side of the connection end surface 15. In FIG. 9, the annular protrusion 72 and the outer peripheral annular portion 73 are shown by cross hatching.

  By providing the high-pressure pipe joint in such a configuration, when the screw member 12 is tightened, the gasket 11 is clamped by the surface pressure sealing force by the annular protrusion 72 to prevent leakage of the ultrahigh-pressure fluid. While exerting, the gasket 11 is clamped by the outer peripheral annular portion 73 and the function of preventing the circumferential connection of the tubular connecting member 70 is exhibited. At this time, the rotation radius of the outer peripheral annular portion 73 is longer than that of the annular protrusion 72, so that the torque on the outer peripheral annular portion 73 side is further increased, and the outer peripheral side of the gasket 11 is reliably prevented from rotating around the outer peripheral annular portion 73 Thus, the annular protrusion 72 provides a sealing property.

  The pressing surfaces 74 and 75 facing each other between the outer peripheral annular portion 73 and the annular projecting portion 72 are provided as flat surfaces. The contact by the flat surfaces 74 and 75 improves the surface pressure sealing force of the outer peripheral annular portion 73 and the annular protrusion 72 to prevent rotation, and reduces the sealing force due to the groove due to sliding contact with the gasket 11 and damage. Prevents and exhibits excellent sealing performance.

Furthermore, if the clamping surfaces 74 and 75 are provided at the same height in the axial direction, the outer peripheral annular portion 73 and the annular protrusion 72 are simultaneously pressed against the gasket 11 during tightening, and the annular protrusion 72 and the outer peripheral annular portion 73 Each function can be generated simultaneously.
If the outer peripheral annular portion 73 and the annular protrusion 72 are provided with substantially the same cross-sectional shape, the seal area is made equal to equalize the surface pressure balance, and the surface pressure can be prevented by applying a biased force. It can be improved.

  A concave flat surface 76 is provided between the outer peripheral annular portion 73 and the annular protrusion 72. Since the gasket 11 is less likely to come into contact with the concave flat surface 76, a small contact area by the outer peripheral annular portion 73 and the annular protrusion 72 can be locally brought into contact with the gasket 11 to improve the seal surface pressure.

  In the present embodiment, as shown in FIG. 8, the outer peripheral annular portion 73 and the annular protrusion 72 are formed in a substantially trapezoidal cross section, and the chamfer 26 is formed on the inner diameter side (flow channel side) of the annular protrusion 72. A chamfer 77 is provided on each outer diameter side. The concave flat surface 76 is provided with a predetermined depth D via chamfered portions 78 and 79 formed on the outer diameter side of the annular protrusion 72 and the inner diameter side of the outer peripheral annular portion 73, respectively. In this high-pressure pipe joint, for example, the outer circumferential annular portion 73 and the annular protrusion 72 have a width L1 of 0.4 mm, a chamfering angle γ of 45 °, and chamfered portions 78 and 79 of 0.2 mm, respectively. The depth D of the surface 76 is provided at 0.2 mm.

  As shown in FIG. 9, the outer peripheral annular portion 73 is provided with a slit 80 at one place by plastic processing such as punching, pressing or the like or cutting processing. The slit 80 is provided in a 45-degree V-groove shape with a depth of 0.2 mm, for example, and the slit 80 can be used as a leak groove to release the pressure in the concave flat surface 76. This prevents the pressure from remaining in the concave flat surface 76 at the time of tightening, and the internal pressure causes a force to be applied in the direction in which the tubular connecting member 70 is separated, while preventing deformation of the gasket 11 and the like. 72, the outer peripheral annular portion 73 can press the gasket 11 evenly, and both the sealing performance by the annular protrusion 72 and the rotation prevention mechanism by the outer peripheral annular portion 73 can be ensured. The slit 80 may be provided at a plurality of locations.

  When the outer peripheral annular portion 73 is provided, it may be provided at the same position as or close to the engaging surface of the projection 19 in the axial direction of the tubular connecting member 70. In this case, the pressing force of the engaging surface 19a when the female nut 17 is tightened. Can be transmitted so as to directly act in the direction of the outer peripheral annular portion 73, and the effect of preventing rotation can be further enhanced, and the sealing performance by retightening can also be effectively improved.

  Here, the high-pressure pipe joint for connecting the tubular connection members 70 in FIG. 6 and the tubular connection in which only the annular protrusion 72 on the inner periphery side is provided in the tubular connection member in FIG. 6 without providing the outer annular portion 73. With respect to the high-pressure pipe joint that connects the members, the size of the rotation for tightening was compared by a test. For convenience, the high pressure pipe joint having two lip-shaped parts of the annular protrusion 72 and the outer peripheral annular part 73 in FIG. 6 is “double lip”, and the high pressure pipe joint having only the annular protrusion 72 is “single lip”. ".

  As a testing method, the tubular connecting members are tightened by hand tightening with a screw member 12 (male screw member 16, female nut 17) through a gasket 11, and in this state, the male screw member 16 side is fixed with a vise etc. The nut 17 was tightened with a tightening torque of 10 N · m from 10 N · m to 50 N · m. The relationship between the tightening torque and the rotation angle of the female nut 17 and the tubular connecting member on the female nut 17 side is shown in the graph of FIG.

In FIG. 10, when the female nut 17 was tightened for the single lip, the tubular connecting member rotated at substantially the same rotation angle. That is, as a result of the tightening rotation of the female nut 17, the tubular connecting member is rotated at substantially the same angle.
On the other hand, with respect to the double lip, while the tightening torque is increased and the rotation angle of the female nut 17 is increasing at an accelerated speed, the rotation angle of the tubular connecting member 70 is maintained at approximately 0 °. That is, in the double lip, it was confirmed that the tubular connecting member 70 is difficult to rotate around the female nut 17 when the female nut 17 is fastened.

  FIG. 11 shows a high-pressure valve, and high-pressure pipe joints are provided on both ends of the high-pressure valve that are connected to the valve body 50. A female screw 51 is provided on both ends of the valve body 50, while a male screw 53 is provided on the connection side of the tubular connecting member 52 with the valve body 50, and the male screw 53 and the female screw 51 are engaged with each other. Thus, the tubular connecting member 52 is integrated with the valve body 50.

  A male threaded portion 54 is integrally formed on the connection side of the tubular connecting member 52 with the external pipe line, and the tubular connecting member 52 is directly screwed into the female nut 17 via the male threaded portion 54, and this female nut. 17 is provided so as to be connectable to the tubular connecting member 10 on the pipe line side. As described above, the tubular connecting member 52 is attached to the valve body 50, so that the male screw portion 54 and the female nut are connected via the high-pressure pipe joint having the tubular connecting member 52 and the tubular connecting member 10 on the pipe line side. The high pressure valve can be connected to the pipe line by tightening the screw member according to 17. Also in this case, as in the above-described embodiment, the connection end surface 15 is provided with the narrow flat seal portion 20, the obtuse angle taper surface 21, and the relief portion 25 shown in FIG. 1, and the gasket 40 due to excessive tightening force. In addition, breakage on the connection end side is prevented, and high sealing performance is maintained.

  In the high-pressure valve, the tubular connecting member 52 is provided with a mounting hole 55, and a seat retainer 57 is mounted in the mounting hole 55 via a disc spring 56. A ball seat 58 is mounted on the front end side of the seat retainer 57, and a ball valve body 60 rotatably provided by a stem 59 is sealed by the ball seats 58, 58 on both sides. With this configuration, the high-pressure valve can flow an ultrahigh-pressure fluid such as hydrogen while preventing leakage. At this time, the high-pressure valve is connected to the external pipe line via the high-pressure pipe joint. Side leakage is also reliably prevented.

  In this embodiment, an example in which the high pressure valve is a ball valve has been described. And a sealing structure can be provided. In this case, the high-pressure pipe joint may be provided only on one side of the connection portion side of the valve, and can be arbitrarily set according to the type of the valve, the use location, and the like. Although the gasket 40 that can be fitted to the inner diameter of the female nut 17 is mounted, it may be mounted via a gasket retainer. Moreover, although the male thread part 54 is integrally formed in the tubular connection member 52, the tubular connection member 10 and the male thread member 16 may be provided in separate structures like the said embodiment. In place of the tubular connection member 52, the tubular connection member 70 can also be connected. In this case, in addition to the high sealing performance, the above-described anti-rotation function can be exhibited.

DESCRIPTION OF SYMBOLS 10, 70 Tubular connecting member 11, 40 Gasket 12 Screw member 15 Connection end surface 20 Narrow plane seal portion 21 Obtuse taper surface 22 Seal portion 25 Relief portion 26 Chamfer 30 Gasket retainer 33 Notch groove 50 Valve body θ Inclination angle 72 Annular Protrusion 73 Peripheral annular portion 74, 75 Clamping surface 76 Concave flat surface 80 Slit

Claims (9)

  A high-pressure pipe joint that connects and connects the connection end surfaces of a pair of tubular connection members by tightening a screw member through a gasket, and the gasket is a metal having a lower hardness than the connection end surfaces, On the connection end surface, a narrow flat seal portion is formed in the innermost side or near the innermost side, and an obtuse angle tapered surface is formed along the outer diameter side of the narrow flat seal portion, and the screw member is tightened. In the case of sealing with the narrow flat seal portion and the obtuse angle tapered surface in an expanded state of the seal portion with the gasket according to the size of the tightening load, and when tightening with the maximum tightening load, the outer diameter A high-pressure pipe joint characterized in that the obtuse angle tapered surface on the side has a seal structure that serves as a stopper, so that the sealing performance is maintained even for an ultra-high pressure fluid.   The high-pressure pipe joint according to claim 1, wherein a relief portion having no stopper structure is provided on the outer diameter side of the obtuse angle tapered surface.   The high-pressure pipe joint according to claim 1 or 2, wherein chamfering is provided on the flow path side of the connection end surface of the tubular connection member to prevent the narrow flat seal portion from being deformed to the flow path side.   The outer diameter of the gasket is provided so as to be fitted to the inner diameter of a female nut constituting the screw member, and the gasket is positioned in the female nut in a centered state. Piping joint for high pressure.   A high-pressure pipe joint that connects and connects the connection end surfaces of a pair of tubular connection members by tightening a screw member through a gasket, and the gasket is a metal having a lower hardness than the connection end surfaces, An annular protrusion is formed in the vicinity of the inner diameter of the connection end surface, and an outer peripheral ring is formed on the outer diameter side of the connection end surface to prevent the tubular connection member from rotating in the circumferential direction by tightening the screw member. A high-pressure pipe joint characterized by providing a section.   The high-pressure pipe joint according to claim 5, wherein a clamping surface between the outer peripheral annular portion and the annular protrusion is a flat surface.   The high-pressure pipe joint according to claim 5 or 6, wherein a concave flat surface is formed between the outer peripheral annular portion and the annular projecting portion.   The high-pressure pipe joint according to any one of claims 5 to 7, wherein a slit for releasing pressure in the concave flat surface is provided in the outer peripheral annular portion.   A high-pressure valve comprising the high-pressure pipe joint according to any one of claims 1 to 8 on a connection portion side of a valve body.

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