JP4721971B2 - Detachment prevention fitting - Google Patents

Description

  The present invention relates to a detachment prevention pipe joint having a structure in which an insertion opening formed at an end portion of the other pipe is inserted into a receiving opening formed at an end portion of one pipe.

  As this type of separation preventing pipe joint, there is one used for a bent portion of a pipeline. An unaverage force based on the fact that the pressure of the fluid in the pipe is not averaged due to the bending of the pipe line acts on the separation preventing pipe joint, and the unaverage force acts in a direction in which the joint is pulled out. As a detachment prevention pipe joint for preventing such a joint from coming off, one shown in FIG. 6 is known (Patent Document 1).

  In FIG. 6, a receiving port 23 is formed at the end of one tube 21 joined to each other, and an insertion port 24 to be inserted into the receiving port 23 is formed at the end of the other tube 22. Yes. Each tube 21, 22 is made of ductile cast iron. Between the inner peripheral surface of the receiving port 23 and the outer peripheral surface of the insertion port 24 inserted into the receiving port 23, a sealing material 25 is disposed in a compressed state. The sealing function is demonstrated.

  An annular insertion flange 26 that does not have a circumferential dividing portion is fitted on the outer periphery of a portion of the insertion opening 24 that is not inserted into the receiving opening 23, and the insertion flange 26 is inserted by a fillet weld portion 27. It is fixed to the insertion slot 24. In addition, an insertion rib 28 is welded to the outer periphery of the insertion opening 24 at predetermined intervals, and an insertion flange 26 is welded to a standing surface of the insertion rib 28, and the insertion opening 24 is interposed via the insertion rib 28. The outer surface and the insertion flange 26 are integrated.

  An annular receiving ring 29 having no circumferential dividing portion is fitted on the receiving opening 23, and the receiving ring 29 is a flange-shaped protrusion 30 formed on the outer periphery of the end of the receiving opening 23. Are arranged so as to be able to engage with each other in the tube axis direction. The insertion flange 26 and the insertion rib 28 are made of structural steel or the like, and the reception ring 29 is made of ductile cast iron or the like.

  A plurality of bolts 31 penetrating the insertion flange 26 and the receiving ring 29 and extending in the tube axis direction are provided at appropriate intervals in the circumferential direction, and nuts 32 are screwed into the tips of the bolts 31. And the nut 32, the insertion flange 26 and the receiving ring 29 are fastened to each other with the protrusion 30 of the receiving port 23 sandwiched therebetween. The bolt 31 and the nut 32 are made of chromium / molybdenum steel or the like.

  With such a configuration, the receiving port 23 and the insertion port 24 are integrated to prevent the tubes 21 and 22 from moving relative to each other in the direction in which they are pulled out from each other. Even if it uses, it can prevent reliably that a joint pulls out by the non-average force of the fluid in a pipe | tube.

When the joint is bent and joined in a state where the receiving port 23 and the insertion port 24 are bent, the bolt 31 is loosened in advance, and the joining of the receiving port 23 and the insertion port 24 in the bent state is completed. Then, the bolt 31 is tightened. By adjusting the tightening length of each bolt 31 provided in a plurality along the circumferential direction of the joint, it corresponds to bending joining.
JP 2001-41367 A

  In such a pipe joint, it may be necessary to adjust the length to a predetermined length by cutting the insertion port 24 side of the pipe 22 depending on the situation of the laying site of the pipe line. However, in the case of the above-described conventional pipe joint, in such a case, the insertion flange 26 and the insertion rib 28 are newly prepared, and the insertion flange 26 and the insertion rib 28 are cut. It is necessary to perform welding and to weld to a new location of the insertion opening 24.

  That is, in this case, since it is necessary to newly prepare the insertion flange 26 and the insertion rib 28, the cost is increased by this amount, and the economic efficiency is deteriorated. Moreover, when welding the insertion flange 26 and the insertion rib 28, since the dimension of the welding part is comparatively long, there also existed a fault which requires a long time for construction. Furthermore, there is a problem that it is not easy to weld the insertion flange 26 at an accurate position at the site where the pipe is laid.

  Further, in the case of the pipe joint having the above-described conventional configuration, the receiving ring 29 is disposed so as to be able to be engaged with the protrusion 30 of the receiving port 23, but the receiving ring 29 is arranged on the receiving port 23 side of the pipe 21. It must be inserted from the opposite side of the tube 21, that is, from the insertion port 24 side of the tube 21, and moved to the receiving port 23 part. Especially when the tube 21 is long, the moving operation of the receiving ring 29 is performed. However, it took a lot of time and effort, causing a reduction in work efficiency.

  The present invention solves the above-mentioned problems, and an object of the present invention is to provide a disconnection prevention pipe joint that can improve the work efficiency at the construction site, including the case of cutting the insertion opening, and is excellent in economy. And

  In order to achieve the above object, the separation preventing pipe joint according to the present invention is a pipe in which an insertion opening formed at the end of the other pipe is inserted into a receiving opening formed at the end of one pipe. A joint, a weld bead formed on the outer periphery of the insertion slot, an outer insertion ring inserted into the insertion slot, and an annular insertion lock ring that is split in the circumferential direction; An annular insertion ring that can be engaged with the ring and does not have a circumferential dividing portion, and one circumferential direction that can be fitted to a protrusion that is externally fitted to the receiving port and formed on the outer periphery of the receiving port. A split annular receiving lock ring, an annular receiving ring that is externally fitted to the receiving opening and has an inner circumferential portion that can engage with the receiving lock ring, and a circumferential dividing portion; It is provided with a plurality, and is fastened with the receiving ring and the insertion ring being restricted in position in the tube axis direction. And a fastening member that holds the state in which the insertion ring abuts the weld bead via the insertion lock ring when the tubes try to move relative to each other in the direction in which the mouth is detached. It is characterized by being.

  In this case, the insertion ring is formed with an inward protruding portion extending inward along the tube radial direction, and on the surface away from the receiving port in the insertion lock ring, the distal end side of the insertion port becomes more outward in the tube radial direction. An inclined surface that is inclined with respect to the outer peripheral surface of the insertion port is formed so that the inner peripheral tip corner of the inner protrusion of the insertion ring can contact the inclined surface of the insertion lock ring in the tube axis direction. It is preferable that it is arrange | positioned.

  Furthermore, it is preferable that the inclination angle of the inclined surface of the insertion lock ring is smaller than the inclination angle with respect to the outer peripheral surface of the insertion opening where the weld bead contacts the insertion lock ring.

  According to the present invention, since the insertion lock ring and the insertion ring are not welded to the insertion opening but merely fitted to the insertion opening, when the insertion side is cut at the construction site of the pipeline However, it is possible to obtain a detachment preventing structure by performing the same work as when no cutting work is performed, and there is no inconvenience that a new insertion ring must be prepared separately. In addition, since it is only necessary to form a weld bead on the outer periphery of the insertion slot, the welded part length can be shortened compared to the conventional case where the insertion ring and the insertion flange are welded. can do. In addition, since the annular receiving ring having no circumferential dividing portion and the protruding portion of the receiving portion are connected to each other through the annular receiving lock ring divided in the circumferential direction, the receiving ring The inner diameter of the receiver can be made larger than the outer diameter of the receiver, and the receiver lock ring can be made larger than the protrusion of the receiver, so that the receiver ring and the receiver lock ring can be received by one of the pipes. It can be externally fitted to the receiving port from the mouth side end face side, and the moving operation of the receiving ring and the receiving lock ring is hardly performed, and the work efficiency is improved.

  In addition, the inner peripheral tip corner of the inner projecting portion extending inward along the tube diameter direction in the insertion ring is in contact with the inclined surface formed on the surface away from the receiving port in the insertion lock ring. Since it is configured, the radial direction of the action point of the force acting in the tube axis direction from the insertion ring in the insertion lock ring and the reaction point of the reaction force acting in the tube axis direction from the weld bead in the insertion lock ring As a result, the moment acting on the insertion lock ring due to the force from the insertion ring and the reaction force from the weld bead is suppressed to a small level. The amount of deformation can be kept small, and as a result, the manufacturing cost can be minimized while maintaining good reliability.

  In addition, the insertion lock ring rides on the weld bead by making the inclination angle of the inclined surface of the insertion lock ring smaller than the inclination angle with respect to the outer peripheral surface of the insertion opening where the weld bead contacts the insertion lock ring. It is possible to reliably prevent the insertion opening from being detached from the receiving opening, thereby further improving the reliability.

  As shown in FIGS. 1 and 2, a receiving port 2 is formed at the end of one tube 1 to be joined to each other, and an insertion inserted into the inside of the receiving port 2 is formed at the end of the other tube 3. A mouth 4 is formed. Each of the tubes 1 and 3 is made of ductile cast iron. A seal material accommodation groove 5 is formed on the inner periphery of the receiving port 2, and an annular rubber seal material 6 is disposed in the accommodation groove 5. The sealing material 6 is compressed between the inner peripheral surface of the receiving groove 5 and the outer peripheral surface of the insertion port 4 inserted into the sealing material 6, so that the receiving port 2 and the insertion port 4 A required sealing function is provided between them. On the outer periphery of the tube 1 in the vicinity of the opening end (referred to as the tube end surface 2a) on the side where the receiving port 2 is provided, a protrusion 7 is formed that projects outwardly in the tube diameter direction in a flange shape, A groove portion 2b that is recessed inward in the radial direction of the tube is formed at a location that is located on the opposite side of the projection 7 from the tube end surface 2a.

  The outer periphery of the portion of the insertion port 4 not inserted into the receiving port 2 protrudes outward in the tube diameter direction with a predetermined cross-sectional shape (for example, a substantially elliptical shape or a cross-sectional shape obtained by halving a simple circle or a mountain shape). The weld bead 8 is formed in a continuous or intermittent state in the circumferential direction.

  An insertion lock ring 9 is fitted on the outer periphery of the insertion port 4 at a position farther from the receiving port 2 than the weld bead 8 in a state where the insertion lock ring 9 is in contact with the outer periphery of the insertion port 4. The welding bead 8 is disposed at a position away from the receiving port 2 so as to be able to engage in the pipe axis direction. Further, the insertion ring 10 is externally fitted with a gap from the outer periphery of the insertion port 4 in a posture so as to cover the insertion lock ring 9 from the outer peripheral side, and the insertion ring 10 is inserted into the insertion lock. The ring 9 is disposed on a surface of the ring 9 away from the receiving port 2 so as to be able to engage in the tube axis direction. Here, the insertion lock ring 9 is formed in a single annular shape in the circumferential direction and is elastically deformable. On the other hand, the insertion ring 10 is formed in an annular shape having no circumferentially divided portion.

  The insertion ring 10 includes a cylindrical portion 10a that covers the insertion lock ring 9 from the outer peripheral side and extends in a cylindrical shape along the tube axis direction so as to face the outer peripheral surface of the insertion port 4, and the cylindrical portion 10a An inner projecting portion 10b extending inward along the tube radial direction so as to be closer to the outer peripheral surface of the insertion port 4 from a location away from the receiving port 2, and a tube diameter than a location near the receiving port 2 in the cylindrical portion 10a A flange portion 10c that extends outward in the direction, and a plurality of reinforcing ribs 10d that are integrally formed so as to straddle the flange portion 10c and the tubular portion 10a and are provided at appropriate intervals in the circumferential direction. .

  Bolt insertion holes 16 along the tube axis direction are formed in the flange portion 10c so as to penetrate through a plurality of positions at appropriate intervals in the circumferential direction. Further, the end surface on the inner side in the tube radial direction from the portion where the bolt insertion hole 16 of the flange portion 10c is formed functions as a tube end surface abutting portion 10f that abuts against and can engage with the tube end surface 2a of the receiving port 2. .

  In addition, an insertion set bolt 11 with a hexagonal hole is screwed into the tubular portion 10a of the insertion ring 10 at a predetermined interval in the circumferential direction to press the insertion lock ring 9 inward in the tube radial direction to reduce the diameter. The insertion port lock ring 9 is disposed so as to be in close contact with the outer peripheral surface of the insertion port 4 by screwing the insertion port set bolt 11 so as to advance inward in the pipe diameter direction. In addition, the insertion lock ring 9 can be elastically deformed in the diameter-expanding direction in a single state that is not pressed by the insertion set bolt 11, and an external force such as an operator is applied in the direction of opening the split portion. Thus, the inner peripheral diameter is configured to be larger than the dimension in the pipe radial direction (referred to as a pipe diameter dimension) where the weld bead 8 is provided. Moreover, the diameter (tube diameter dimension) of the inner peripheral surface of the inner protrusion 10b which is the innermost peripheral part of the insertion ring 10 is formed to be larger than the pipe diameter dimension of the place where the weld bead 8 is provided. ing.

  A receiving lock ring 12 is externally fitted in the groove 2b of the receiving port 2. The receiving lock ring 12 is arranged so as to be able to engage with the surface along the tube radial direction in the groove 2b of the receiving port 2 in the tube axis direction. It is installed. Further, the receiving ring 13 is externally fitted with a clearance from the outer periphery of the receiving port 2 so as to cover the receiving lock ring 12 from the outer peripheral side. The ring 12 is disposed on the surface of the ring 12 away from the tube end surface 2a so as to be able to engage in the tube axis direction. Here, the receiving port lock ring 12 is formed in a ring shape that is divided into one piece in the circumferential direction, and can be elastically deformed. On the other hand, the receiving ring 13 is formed in an annular shape having no circumferential dividing portion.

  The receiving ring 13 includes a cylindrical portion 13a extending in a cylindrical shape in a posture facing the outer periphery of the receiving port 2 in a posture so as to cover the receiving lock ring 12 from the outer peripheral side, and a tube of the receiving port 2 in the cylindrical portion 13a. A flange portion 13b extending inward in the pipe radial direction so as to approach the outer periphery of the receiving port 2 from a position away from the end surface 2a, and a flange portion 13b provided at an appropriate interval in the circumferential direction. Reinforcing ribs 13c extending inward in the tube radial direction so as to approach the outer periphery of the receiving port 2 from a location closer to the tube end surface 2a of the receiving port 2 than the location where the receiving port 2 is provided. Bolt insertion holes 17 in the tube axis direction are formed in the flange portion 13b so as to penetrate through a plurality of positions at appropriate intervals in the circumferential direction. Further, the inner peripheral portion of the surface of the flange portion 13b close to the receiving tube end surface 2a can be brought into contact with and contact with the surface of the receiving lock ring 12 on the side away from the receiving tube end surface 2a. It is configured.

  Further, the tubular portion 13a and the reinforcing rib 13c of the receiving ring 13 are provided with hexagonal holes for reducing the diameter by pressing the receiving lock ring 12 inwardly in the pipe radial direction at predetermined intervals in the circumferential direction. The set bolt 18 is screwed, and the receiving port set bolt 18 is disposed so as to be in close contact with the outer peripheral surface of the receiving port 2 by screwing the receiving port set bolt 18 so as to advance inward in the pipe diameter direction. Yes. The receiving lock ring 12 can be elastically deformed in the diameter-expanding direction in a single state that is not pressed by the receiving set bolt 18, and an external force such as an operator is applied in the direction of opening the split portion. Thus, the inner peripheral diameter is configured to be larger than the pipe diameter of the portion where the protrusion 7 of the receiving port 2 is provided. Further, the pipe diameter dimension of the inner peripheral surface of the flange portion 13b which is the innermost peripheral portion of the receiving ring 13 is formed larger than the pipe diameter dimension of the portion where the outer peripheral projection 7 of the receiving opening 2 is provided. ing.

  As shown in FIG. 1, a bolt 14 is inserted in the tube axis direction through a bolt insertion hole 16 of the insertion ring 10 and a bolt insertion hole 17 of the receiving ring 13, and a nut 15 is screwed to the bolt 14 and fastened. A plurality of bolts 14 and nuts 15 functioning as fastening members are provided at appropriate intervals along the circumferential direction of the receiving ring 13 and the insertion ring 10. Then, by screwing nuts 15 into these bolts 14, the receiving ring 13 and the insertion ring 10 can be tightened together. When the receiving ring 13 and the insertion ring 10 are tightened in this way, the receiving lock ring 12 pressed in the tube axis direction by the receiving ring 13 and the tube end surface abutting portion 10f of the insertion ring 10 The protrusion 7 of the receiving port 2 is sandwiched, and the one tube 1 provided with the receiving port 2, the receiving port lock ring 12, the receiving ring 13, and the insertion ring 10 are integrated.

In particular, the engagement structure between the insertion ring 10 and the insertion lock ring 9 is as shown in FIGS. That is, as shown in FIG. 3 and FIG. 4 in an enlarged manner, the insertion ring 10 has a tube diameter close to the inner peripheral surface and the receiving port 2 in the inner protrusion 10b extending inward along the tube radial direction. A corner portion (referred to as an inner peripheral tip corner portion) 10 g intersecting with the surface along the direction is configured to engage the insertion lock ring 9. Further, the surface of the insertion lock ring 9 with which the inner peripheral tip corner 10g of the insertion ring 10 is engaged, that is, the surface of the insertion lock ring 9 away from the receiving port 2 is closer to the outer side in the tube radial direction. an inclined posture closer to the distal end side, is constituted by the inclined surface 9a inclined at a predetermined angle theta ₁ with respect to the outer peripheral surface of the inserting 3. Then, the inclination angle θ ₁ of the inclined surface 9 a of the insertion lock ring 9 is smaller than the inclination angle θ _{2 with} respect to the outer peripheral surface of the insertion opening 3 where the weld bead 8 contacts the insertion lock ring 9. Is formed. In addition, the inclination direction of the location which contacts the insertion lock ring 9 of the weld bead 8 is also a direction inclined in such a posture as to approach the distal end side of the insertion opening 4 toward the outer side in the pipe radial direction.

  In the pipe joint having such a configuration, when the receiving port 2 and the insertion port 4 are joined, first, the sealing material 6 is disposed in the seal housing groove 5 of the receiving port 2. Also. The receiving ring 13 is fitted on the receiving port 2, and then the receiving lock ring 12 is fitted on the groove 2 b of the receiving port 2.

  At this time, the tube diameter dimension of the inner peripheral surface of the flange portion 13b which is the innermost peripheral portion of the receiving ring 13 is formed larger than the tube diameter dimension of the portion where the outer peripheral protrusion 7 of the receiving port 2 is provided. Therefore, the receiving ring 13 can be easily fitted from the side where the receiving port 2 of the one tube 1 is provided. Further, since the receiving lock ring 12 is formed in a ring shape that is divided into one piece in the circumferential direction, it is fitted outside in a state where an external force is applied so as to expand the diameter so as to get over the protrusion 7 of the receiving port 2. By moving the tube 1 in the tube axis direction, the tube 1 can be externally fitted from the side where the receiving port 2 of the tube 1 is provided. After the receiving lock ring 12 and the receiving ring 13 are externally fitted to the receiving port 2 in this way, the receiving lock ring 12 is reduced in diameter by screwing the receiving set bolt 18, so that the receiving lock ring 12. The inner peripheral surface is closely attached to the outer peripheral surface of the receiving port 2.

  Further, the insertion ring 10 is first fitted on the insertion slot 4 in which the weld bead 8 is formed in advance, and then the insertion lock ring 9 is fitted. At this time, the pipe diameter dimension of the inner peripheral surface of the inner protrusion 10b which is the innermost peripheral part of the insertion ring 10 is formed larger than the pipe diameter dimension of the portion where the weld bead 8 is provided. Therefore, it is possible to easily fit the insertion ring 10 from the side where the insertion opening 4 of the other tube 3 is provided. Moreover, since the insertion lock ring 9 is formed in an annular shape that is divided into one piece in the circumferential direction, it is fitted outside with an external force applied so as to expand the diameter so as to get over the weld bead 8 of the insertion opening 4. By moving the tube 3 in the direction of the tube axis, the tube 3 can be externally fitted from the side where the insertion port 4 of the other tube 3 is provided. After the insertion lock ring 9 and the insertion ring 10 are externally fitted to the insertion port 4 in this manner, the insertion lock ring 9 is reduced in diameter by screwing the insertion set bolt 11, and the insertion lock ring 9. Is brought into close contact with the outer peripheral surface of the insertion opening 4.

  In this state, the insertion opening 4 is inserted into the receiving opening 2, and the sealing material 6 is compressed between the receiving opening 2 and the insertion opening 4. Further, the bolt 14 is passed through the bolt through hole 17 of the receiving ring 13 and the bolt through hole 16 of the insertion ring 10, and the nut 15 is tightened from the tip of the bolt 14 to complete the joining state shown in FIGS. 1 and 2. And

  According to the above-described configuration, the insertion lock ring 9 and the insertion ring 10 are not welded to the insertion port 4 but are simply fitted to the insertion port 4, so that they are inserted at the construction site of the pipe. Even when the side of the mouth 4 is cut, a detachment prevention structure can be obtained by performing the same work as when the cutting work is not performed, and there is no inconvenience that a new insertion ring or the like has to be prepared separately. .

  In addition, since it is only necessary to form the weld bead 8 on the outer periphery of the insertion port 4, the welded portion length can be shortened compared to the conventional case where the insertion ring and the insertion flange are welded. It can be easily installed on site.

  In addition, since the annular receiving ring 13 having no circumferential dividing portion and the protruding portion 7 of the receiving port 2 are engaged with each other through the annular receiving lock ring 12 divided in the circumferential direction. The inner diameter of the receiving ring 13 can be formed larger than the outer diameter of the receiving opening 2 and the receiving lock ring 12 can be made larger in diameter than the protrusion 7 of the receiving opening 2. The receiving lock ring 12 can be externally fitted to the receiving port 2 from the tube end surface 2a side of the receiving port 2 of one of the tubes 1, and the moving operation of the receiving ring 13 and the receiving lock ring 12 can be hardly performed. , Work efficiency will be good.

  Further, according to the above configuration, the insertion ring 10 can be engaged with the weld bead 8 via the insertion lock ring 9 in the tube axis direction by tightening the bolt 14 and the nut 15. Even if it is used for the bent portion of the pipe, it is possible to prevent the joint from coming out due to the non-average force of the fluid in the pipe.

Here, the behavior of the insertion lock ring 9 when a non-average force is applied along the tube axis direction will be described in detail.
When a non-average force is applied in the direction in which the receiving port 2 comes out of the insertion port 4, this force acts on the insertion lock ring 9 from the insertion ring 10, and further, from the insertion lock ring 9 to the weld bead 8. This force is applied and received by the weld bead 8. At the same time, the reaction force from the weld bead 8 acts on the insertion lock ring 9, and the reaction force from the insertion lock ring 9 acts on the inner protrusion 10 b of the insertion ring 10.

  That is, at this time, the insertion lock ring 9 receives a force Fa along the tube axis direction from the contact point with the inner peripheral corner 10g of the insertion ring 10 as shown in FIG. 8, a reaction force Ta is received along the tube axis direction from a contact point with 8 (that is, a point on the outer periphery of the insertion port 4 where the weld bead 8 is substantially formed). Therefore, if the distance between the contact point of the insertion lock ring 9 with the inner peripheral tip corner 10g of the insertion ring 10 and the contact point with the weld bead 8 is large, the insertion lock ring 9 A large moment M around the contact point with the weld bead 8 is generated inside. Therefore, if it is such a structure, for example, it will pass for a long time after installing pipes 1 and 2, and the insertion set bolt 11 will corrode etc. If a non-average force is applied in a state where no force is applied, the insertion lock ring 9 may be deformed by the moment M generated in the insertion lock ring 9. In order to prevent such a problem, it is necessary to use a large cross-sectional area as the insertion lock ring 9 in order to suppress deformation of the insertion lock ring 9, and in this case, the manufacturing cost is accordingly increased. Increase.

  However, in the present invention, the inner ring-shaped portion 10b extending inward along the tube radial direction is formed on the insertion ring 10, and the surface of the insertion lock ring 9 that is in contact with the insertion ring 10 is formed with the tube diameter. Since it is constituted by the inclined surface 9a that is closer to the distal end side of the insertion opening 4 toward the outer side in the direction, the insertion ring 10 and the insertion opening are formed at the inner peripheral distal end corner portion 10g that is the innermost peripheral portion in the tube diameter direction of the insertion ring 10 The lock ring 9 is always engaged. Therefore, the contact point of the inner peripheral tip corner 10g that is the point of action of the force Fa acting in the tube axis direction from the insertion ring 10 in the insertion lock ring 9 and the weld bead 8 in the insertion lock ring 9 in the tube axis direction. The dimension L in the tube radial direction with the point of action of the reaction force Ta acting on the tube is minimized. As a result, the moment M acting on the insertion lock ring 9 due to the force Fa from the insertion ring 10 and the reaction force Ta from the weld bead 8 can be suppressed to a small value. However, the amount of deformation can be kept small, and as a result, the manufacturing cost can be minimized while maintaining good reliability.

  By the way, when the moment M generated in the insertion lock ring 9 is suppressed to be small as described above, the contact point between the insertion lock ring 9 and the weld bead 8 is pressed toward the outer periphery of the insertion port 4. Since the force is also reduced, the insertion lock ring 9 tends to ride on the inclined surface with which the weld bead 8 abuts in some cases, and in the worst case, the receiving port 2 may come out of the insertion port 4.

However, in the present invention, the inclination angle θ ₁ of the inclined surface 9 a of the insertion lock ring 9 is smaller than the inclination angle θ _{2 with} respect to the outer peripheral surface of the insertion opening 3 where the weld bead 8 contacts the insertion lock ring 9. Therefore, even when an unbalanced force acts in the direction in which the insertion slot 4 comes out of the receiving slot 2, the insertion slot lock ring 9 does not ride on the weld bead 8, and the insertion slot 4 and It is possible to prevent the receiving port 2 from being separated from each other.

This point will be described in more detail with reference to FIG.
The weld bead 8 is formed in a state of being stacked on the outer periphery of the insertion opening 4, but the portion of the welding bead 8 that contacts the insertion lock ring 9 is formed in a slightly inclined state. Therefore, when observing only the force relationship between the weld bead 8 and the insertion lock ring 9, when a force along the tube axis direction is applied from the insertion lock ring 9 to the weld bead 8, the insertion from the weld bead 8 to the insertion bead is performed. A reaction force Ta along the tube axis direction equivalent to the force from the insertion lock ring 9 acts on the lock ring 9 and a force Tb corresponding to the inclination angle at the contact point of the weld bead 8 is generated. This force acts as a force A that causes the insertion lock ring 9 to ride on the weld bead 8.

  For this reason, the cross-sectional shape of the insertion lock ring 9 is a mere rectangle, and the surface of the insertion lock ring 9 that abuts on the inner protrusion 10b of the insertion ring 10 is not an inclined surface, but is along the tube radial direction. If it is a vertical surface, only the force along the tube axis direction acts from the insertion ring 10 to the insertion lock ring 9. Therefore, for example, in a state where a long time has passed since the installation of the pipes 1 and 2 and the insertion set bolt 11 is corroded, the inward force in the pipe radial direction by the insertion set bolt 11 does not act. When the average force is applied, the insertion slot lock ring 9 tends to ride on the inclined surface with which the weld bead 8 abuts. In the worst case, the receiving slot 2 may come out of the insertion slot 4.

However, in the present invention, the portion of the insertion lock ring 9 that engages the insertion ring 10 is configured by the inclined surface 9a that is inclined so as to approach the distal end side of the insertion port 4 toward the outer side in the tube radial direction. When a non-average force acts in the direction in which the receiving port 2 comes out of the insertion port 4, that is, along the tube axis direction, a force Fa along the tube axis direction is generated from the insertion ring 10 to the insertion lock ring 9. At the same time, a force Fb corresponding to the inclination angle θ ₁ of the inclined surface 9 a is generated in a direction in which the insertion lock ring 9 is pressed against and closely contacted with the outer periphery of the insertion opening 4. And the inclination angle θ ₁ of the inclined surface 9 a of the insertion lock ring 9 is formed so as to be smaller than the inclination angle θ _{2 with} respect to the outer peripheral surface of the insertion opening 3 where the weld bead 8 contacts the insertion lock ring 9. Therefore, rather than the force Tb which is received from the weld bead 8 and is about to ride on the weld bead 8, the force Fb which is pressed against the outer periphery of the insertion port 4 received on the inclined surface 9 a of the insertion port lock ring 9. As a result, the insertion lock ring 9 is good even when the insertion set bolt 11 is corroded so that the inward force of the insertion set bolt 11 is not applied in the pipe radial direction. Thus, the outer periphery of the insertion port 4 is pressed against and closely contacted with each other, so that the receiving port 2 can be reliably prevented from coming out of the insertion port 4.

That is, the force that the insertion lock ring 9 tries to ride on the weld bead 8 is A, the force that acts perpendicularly from the insertion ring 10 to the inclined surface 9 a of the insertion lock ring 9 is F, and the insertion ring 10. The force acting on the inclined surface 9a of the insertion lock ring 9 along the tube axis direction is Fa, and the force acting on the inclined surface 9a of the insertion lock ring 9 along the tube radial direction is Fb. Fc is the force along the tube axis direction that the insertion port 4 is about to come out of the receiving port 2 from the mouth lock ring 9 to the insertion ring 10, and T is the force acting on the insertion lock ring 9 from the weld bead 8. When the force acting along the tube axis direction from the weld bead 8 to the insertion lock ring 9 is Ta, and the force acting along the tube diameter direction from the weld bead 8 to the insertion lock ring 9 is Tb,
A = Tb-Fb
= T · cos θ ₂ −F · cos θ ₁
= (Fc / sin θ ₂ ) · cos θ ₂ − (Fc / sin θ ₁ ) · cos θ ₁
(∵Fc = F · sin θ ₁ = T · sin θ ₂ )
= Fc. ((1 / tan θ ₂ ) − (1 / tan θ ₁ ))
Therefore, when θ ₂ > θ ₁ (the inclination angle θ ₂ of the weld bead 8 is larger than the inclination angle θ ₁ of the inclined surface 9a of the insertion lock ring 9), A <0 (the insertion lock ring 9 is welded) The force to ride on the bead 8 becomes a negative value), and the insertion lock ring 9 does not ride on the weld bead 8. In other words, the insertion lock ring 9 does not ride on the weld bead 8 by setting so that θ ₂ > θ ₁ .

In this case, the inclination angle θ ₁ of the inclined surface 9 a of the insertion lock ring 9 is smaller than the inclination angle θ ₂ of the weld bead 8, but the inclination angle θ ₂ of the weld bead 8 is The inclination angle is as large as possible within a range that does not exceed. That is, when the inclination angle theta ₁ of the inclined surface 9a of the inserting the lock ring 9 is small, correspondingly, inward force Fb of the pipe diameter direction acting from the inserting ring 10 to the spigot locking ring 9 is increased, In this case, the force Fb may cause the insertion port 4 itself to be deformed in the diameter-reducing direction, or the inner protrusion 10b of the insertion ring 10 may be deformed so as to be pushed outward in the tube diameter direction. There is. Therefore, the inclination angle θ ₁ of the inclined surface 9 a of the insertion lock ring 9 is smaller than the inclination angle θ ₂ of the weld bead 8 so as to be as large as possible within this range so that such a problem does not occur. It is set to an angle. Further, in this case, the inner protruding portion 10b of the insertion ring 10 is not provided so as to be inclined from the cylindrical portion 10a of the insertion ring 10, but is bent inward in the pipe radial direction from the cylindrical portion 10a. Since the inner protrusion tip 10b of the inner protrusion 10b is in contact with the insertion lock ring 9, the inclination angle θ1 of the inclined surface 9a of the insertion lock ring 9 is set. There is an advantage that it can be freely selected, that is, a large inclination angle can be freely selected.

Further, as a more specific shape of the weld bead 8 or the insertion lock ring 9, the inclination angle θ ₂ of the weld bead 8 is 70 degrees or more and 85 degrees or less, and the inclination of the inclined surface 9 a of the insertion lock ring 9. The angle θ ₁ is preferably in the range of 65 degrees or more and 80 degrees or less, and in any case, the inclination angle θ ₁ is set so that the inclination angle θ ₂ is smaller.

  As the dimensions of the weld bead 8, when the tube diameter is 1200 mm or more, a width of 12 to 18 mm and a height of 4 to 6 mm are preferable, and when the tube diameter is less than 1200 mm, a width of 7 to 13 mm, A height of 3 to 5 mm is preferred.

  Thereby, even when an unbalanced force acts in a direction in which the insertion opening 4 is pulled out from the receiving opening 2, the insertion opening 4 and the insertion ring 10 can be reliably prevented from being detached from the receiving opening 2. Deformation can also be satisfactorily prevented.

As a method for forming the weld bead 8, for example, as shown in FIG. 5, a pair of copper bands 19 are wound around the outer periphery of the insertion opening 4 with a gap corresponding to the width of the welded portion. It is preferable to form the weld bead 8 by turning the welded portions 8a and 8b between the bands 19 to rotate. At this time, since the ground contact inclination angle θ _{2 on the} outer periphery of the insertion hole of the weld bead 8 is small only by welding once, the inclination angle θ _{2 is} obtained by performing the welding operation twice, that is, by doubling. Large weld beads 8 can be obtained. Therefore, by forming the weld bead 8 having the large inclination angle θ ₂ in this way, the insertion lock ring 9 having a large inclination angle θ ₁ of the inclined surface 9a can be used. It is possible to reliably prevent the mouth 4 itself from being deformed in the diameter reducing direction, and the inner projecting portion 10b of the insertion ring 10 from being deformed so as to be pushed outward in the tube diameter direction. Can be improved.

Sectional drawing of the separation prevention pipe joint concerning embodiment of this invention is shown, and the state cut | disconnected by the bolt insertion location is shown. Sectional drawing of the separation prevention pipe joint is shown, and the state cut | disconnected in the location where the volt | bolt is not penetrated is shown. It is a principal part enlarged view of the insertion lock ring in FIG. 1, and its vicinity part. It is a principal part enlarged view of the insertion lock ring in FIG. 1, and its vicinity part. It is a principal part enlarged view explaining the formation method of a weld bead. It is sectional drawing of the conventional detachment prevention pipe joint.

Explanation of symbols

1 tube 2 receiving port 3 tube 4 inserting port 7 projecting portion 8 welding bead 9 inserting port lock ring 10 inserting port ring 11 inserting port set bolt 12 receiving port lock ring 13 receiving port ring

Claims (3)

A pipe joint in which an insertion port formed at the end of the other pipe is inserted inside the receiving port formed at the end of one pipe,
A weld bead formed on the outer periphery of the insertion opening;
An annular insertion lock ring that is externally fitted to the insertion opening and is divided into one piece in the circumferential direction;
An annular insertion ring that is externally fitted to the insertion opening, can be engaged with the insertion lock ring, and does not have a circumferential dividing portion;
A ring-shaped receiving lock ring that is split into one in the circumferential direction and can be fitted to a protrusion formed on the outer periphery of the receiving port.
An annular receiving ring that is externally fitted to the receiving port and does not have a circumferentially divided portion in which the inner peripheral portion can engage with the receiving lock ring;
A plurality of pipes are provided in the circumferential direction, and the pipes try to move relative to each other in the direction in which the insertion opening is separated from the reception opening by fastening the reception ring and the insertion ring in a state in which the position of the reception opening and the insertion ring is restricted in the tube axis direction. And a fastening member that maintains a state in which the insertion ring abuts the weld bead via the insertion lock ring so as to prevent movement. In the insertion ring, an inward protruding portion extending inward along the tube diameter direction is formed,
On the surface away from the receiving port in the insertion lock ring, an inclined surface that is inclined with respect to the outer peripheral surface of the insertion port is formed so as to approach the distal end side of the insertion port toward the outer side in the tube radial direction
2. An anti-detachment tube according to claim 1, wherein an inner peripheral tip corner portion of the inner protrusion in the insertion ring is disposed so as to be able to engage with the inclined surface of the insertion lock ring in the tube axis direction. Fittings.   3. The detachment prevention pipe joint according to claim 2, wherein the inclination angle of the inclined surface of the insertion lock ring is smaller than the inclination angle with respect to the outer peripheral surface of the insertion opening at a location where the weld bead contacts the insertion lock ring.

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