Pipe connection

Abstract

In a pipe fitting 1, a pipe head 5 is inserted into a socket 3; a lock ring 8 is fitted into a lock ring groove 7 formed in the inner periphery of the socket 3; and an engaging portion 15 is formed in the outer periphery of the pipe head 5, wherein the engaging portion 15 engages with the lock ring 8 from the rear side of the socket in the separation direction A from the pipe head 5, thereby preventing the pipe head 5 from being separated from the socket 3. The engaging portion 15 is formed at a position extending backward from the distal end of the pipe head 5 in the separation direction A from the pipe head 5. A bending restraining member 35 is provided to restrain the socket 3 and the head tube 5 in the bending direction C between the inner periphery of the socket 3 and the outer periphery of the head tube 5 in the region between the distal end of the head tube 5 and the engaging portion 15.

Description

Description Invention title: Pipe connection Technical background

[0001] The present invention relates to a pipe connection that has a preventive function against separation, the pipe connection must ensure a predetermined level of bending strength against flexibility to withstand the thrust force (unbalanced force) acting on the pipeline. Prior knowledge

[0002] Typically, for a pipe connection of this type, for example, there is a pipe connection 100 in which a pipe 104 is inserted from a first pipe 103 into a socket 102 of a second pipe 101, as shown in FIG. 15. A groove corresponding to a locking ring 105 is formed in the inner periphery of the socket 102, and a locking ring 106 is positioned in the groove corresponding to the locking ring 105. A pipe head protrusion 107 is formed on the outer periphery of the pipe head 104. The pipe head 104 can be prevented from being separated from the socket 102 by the pipe head protrusion 107 engaging with the locking ring 106 from the back of the socket in the separation direction A from the pipe head 104.

[0003] Generally, the thrust force (the force required to move the pipe by the water pressure in the pipe) is applied to the curved portion, branch portion of the pipeline, or the like. If the pipe joint 100 with the separation preventive function as described above is used for the pipeline to which such thrust force is applied, the pipeline expands / contracts or bends in the direction in which the thrust force is applied. The expansion / contraction function of the pipe joint 100 causes the sealing of the pipe joint 100 to be adversely affected.

[0004] As a countermeasure for this, a cylindrical cover 108 is installed between the distal end of the pipe head 104 and the end portion of the socket 102 of the pipe connection 100, which is located in the area where the pipeline thrust force is applied.

[0005] Since the installation of such a liner 108 secures the pipe head 104 from relative movement in the pipe axis direction in the socket 102, expansion / contraction and leakage of the pipe connection 100 are limited and the bending stiffness of the pipe connection 100 is increased, thereby being able to withstand thrust force. Note that as the pipe connection 100 as described above, Japanese Patent No. 2004-263813 may be referred to. Summary of the invention Technical problems

[0006] However, unfortunately a conventional system described above cannot achieve sufficient bending strength of the pipe connection 100 by installing the liner 108 alone, especially when the diameters of the pipes 101 and 103 are large. The aim of the present invention is to provide a pipe connection that allows for achieving sufficient bending strength. A solution to the problem

[0007] The pipe connection of this invention includes: A socket from the first pipe; A second pipe socket, the first pipe pipe must be inserted into the second pipe socket; A groove compatible with the locking ring formed in the interior of the socket; A locking ring that must be placed in the locking ring groove; and An engaging portion formed on an outer periphery of the pipe head, the engaging portion must engage with the locking ring from the back side of the socket in the direction of separation of the pipe head to prevent separation of the pipe head from the socket, wherein The engaging portion is formed in a position that retracts from the distal end of the header in the direction of separation of the header, and A bending restraining member is provided for restraining the socket and the head tube in the direction of bending between the inner periphery of the socket and the outer periphery of the head tube in the range between the distal end of the head tube and the engaging portion.

[0008] Accordingly, since the socket and the pipe head are restrained in the bending direction by providing a bending restraining member between the inner periphery of the socket and the outer periphery of the pipe head in the range between the distal end of the pipe head and the engaged portion, the bending stiffness of the pipe connection is increased, thereby enabling sufficient bending stiffness to be achieved.

[0009] With respect to the pipe connection of the present invention, the bending restraining member is preferably a ring-shaped member. According to the pipe connection of the present invention, the bending restraining member is preferably divided into a number of arcuate bending restraining pieces in the circumferential direction.

[0010] Accordingly, by placing each bending piece between the inner periphery of the socket and the outer periphery of the head tube in the range between the distal end of the head tube and the engaging portion in a ring-like manner, the bending restraining member can be easily mounted. According to the pipe connection of the present invention, an expansion / contraction restraining member is provided for restraining the socket and the pipe head in the direction of the pipe axis preferably between the distal end of the pipe head and the rear end portion of the socket. Accordingly, the expansion / contraction of the pipe connection is limited and the bending stiffness of the pipe connection is increased. With respect to the pipe connection of the present invention, the expansion / contraction restraining member is preferably a ring-shaped member.

[0011] According to the pipe connection of the present invention, the expansion / contraction restraining member preferably prevents the bending member from being deflected in the direction of the pipe axis through the inner periphery of the socket and the outer periphery of the pipe head and from sliding outwardly from the distal end of the pipe head and the rear end of the socket. Accordingly, the flexural member can be prevented from sliding outwardly between the inner periphery of the socket and the outer periphery of the head tube between the distal end of the head tube and the rear end portion of the socket to be separated. Advantages of the present invention

[0012] According to the present invention as described above, since the socket and the pipe head are restrained in the bending direction by providing a bending restraining member between the inner periphery of the socket and the outer periphery of the pipe head in the range between the distal end of the socket, the pipe head and the engaging portion, the bending rigidity of the pipe connection is increased, thereby enabling sufficient bending strength to be achieved. Brief description of the shapes

[0013] [Figure 1] Figure 1 is a plan view of a pipeline with a pipe connection according to an embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view of the corresponding pipe connection. [Figure 3] Figure 3 shows a locking ring whose diameter is expanded, the locking ring should be provided as per the same at the pipe connection. [Figure 4] Figure 4 is a cross-sectional view of the ring body as provided at the pipe connection. [Figure 5] Figure 5 is a perspective view of the ring body as provided in the pipe connection. [Figure 6] Figure 6 shows a view taken along arrow XX in Figure 2. [Figure 7] Figure 7 shows the view taken along arrow ZZ in Figure 6. [Figure 8] Figure 8 shows the view taken along arrow YY in Figure 2. [Figure 9] Figure 9 is a sectional view to show the method of connecting pipes at the pipe joint based on the same. [Figure 10] Figure 10 is a sectional view to show the method of connecting pipes at the pipe joint based on the same. [Figure 11] Figure 11 is a sectional view to show the method of connecting pipes at the pipe joint based on the same. [Figure 12] Figure 12 is a cross-sectional view to show the method of connecting pipes at the pipe joint in accordance with the same. [Figure 13] Figure 13 is a sectional view to show the method of connecting pipes at the pipe joint based on the same. [Figure 14] Figure 14 is a sectional view to show the method of connecting pipes at the pipe joint based on the same. [Figure 15] Figure 15 is a cross-sectional view of a typical pipe joint. Description of the embodiments

[0014] In the following, an embodiment of the present invention will be described with reference to the drawings.

[0015] As shown in FIG. 1 , a pipeline 50, which is formed by connecting a plurality of pipes, has a bent portion 51 bent at a right angle, and a pipe joint 1. A thrust force 52 is applied to the bent portion 51.

[0016] In the pipe connection 1, which has a separation preventive function, a pipe head 5 is inserted from a first pipe 4 into the socket 3 of the second pipe 2. Note that ductile iron pipes are used for these pipes 2 and 4.

[0017] As shown in Fig. 2, a locking ring groove 7 is formed on the inner peripheral surface of the socket 3 over the entire circumference. The locking ring groove 7 accommodates a locking ring 8 and an annular pressing member 9 that presses the locking ring 8 inward in the radial direction of the pipe.

[0018] As shown in Figure 3, the lock ring 8 is a ring having a slot structure in which a portion thereof is cut out. The lock ring 8 has an elastic property such that its diameter is expanded by expanding the width 12 of the cut out portion 11 with the expander 13 and is reduced by removing the expander 13 from the cut out portion 11 to return to the original diameter.

[0019] As shown in Fig. 2, a head tube protrusion 15 (an example of an engaging portion) is formed on the outer periphery of the head tube 5 over the entire circumference. The head tube protrusion 15 is formed at a position that is set back by a predetermined distance from the distal end of the head tube 5 in the separation direction A from the head tube 5. The head tube 5 can be prevented from being separated from the socket 3 by engaging the head tube protrusion 15 with the lock ring 8 from the rear side of the socket in the separation direction A from the rod 5. Note that when the head tube protrusion 15 is engaged with the lock ring 8, as described above, a distance D between the distal end of the socket of the rod 5 and an end plate 37 (an example of a rear end portion) of the socket 3 is maximized.

[0020] As shown in Fig. 11, the inner peripheral surface of the socket 3 includes a conical portion 16 whose diameter gradually decreases from an opening end face toward the back of the socket 3, a straight portion 17 extending directly from the rear end of the conical portion 16 toward the back, and a socket protrusion 18 projecting inward from the rear end of the straight portion 17 in the radial direction of the pipe. The straight portion 17 is formed to have a constant inner diameter in the pipe axis direction. The socket protrusion 18 is formed in the entire circumference between the straight portion 17 and the ring groove of the lock 7 in the pipe axis direction and has a smaller inner diameter than the straight portion 17.

[0021] As shown in Fig. 2, on the end side of the socket opening relative to the lock ring 8, a sealing gasket 19 is provided which is compressed in the radial direction of the pipe to seal between the inner peripheral surface of the socket 3 and the outer peripheral surface of the pipe head 5. The sealing ring 19 is a ring made of rubber (rubber ring) and is placed in the seating space of the sealing gasket 20. Note that the seating space of the sealing gasket 20, as shown in Fig. 11, is formed in the entire circumference between the conical portion 16 and the straight portion 17 of the socket 3, and the outer peripheral surface of the pipe head 5.

[0022] As shown in Figure 2, a press ring 22 is provided for pressing the sealing washer 19 towards the back of the socket at the end portion of the socket opener 3. The press ring 22 has an adjacent portion 23 which is connected to the end portion of the socket opener 3 in the pressing direction B where it presses the sealing washer 19 and is connected to the end portion of the socket opener 3 by a number of bolts 25 and nuts 26.

[0023] A ring body 31 is provided between the lock ring 8 and the sealing gasket 19 in the pipe axis direction. As shown in FIGS. 2, 4 and 5, the ring body 31, which is a ring having a slot structure with a portion cut out, is made of a material such as an elastic resin. The ring body 31 has an annular main body portion 32 having a slot structure and a deflection prevention member 33 for preventing the main body portion 32 from being deflected toward the opening end of the socket 3.

[0024] The main body portion 32 has a rectangular cross-sectional shape and is positioned between the inner peripheral surface of the socket protrusion 18 and the outer peripheral surface of the pipe head 5, thereby moving the pipe head 5 in the radial direction of the socket pipe 3 such that the deviation between the first pipe axis 4 and the second pipe axis 2 in the radial direction of the pipe is reduced.

[0025] The height H in the radial direction from the inner peripheral surface 53 to the outer peripheral surface 54 of the main body part 32 is set to less than half the difference between the minimum allowable inner diameter of the socket protrusion 18 and the maximum allowable outer diameter of the head tube 5.

[0026] In the deflection preventing member 33, the distal end portion in the pipe axis direction is engageable against the straight portion 17 of the inner peripheral surface of the socket 3, and the base end portion in the pipe axis direction is integrally provided on the inner peripheral side of the main body portion 32. The deflection preventing member 33 has a ring shape whose diameter expands conically from the base end portion to the distal end portion, and also has a slot structure. Note that a gap 38 is formed around the entire circumference between the sealing gasket 19 and the ring body 31 in the direction of the pipe axis.

[0027] In addition, as shown in Fig. 2, the pipe connection 1 is provided with an expansion / contraction restraining member 34 and a bending restraining member 35 to resist the thrust force 52 (refer to Fig. 1). The expansion / contraction restraining member 34 is a member that restricts the socket 3 and the pipe head 5 in the pipe axis direction and is movably positioned between the distal end of the pipe head 5 and the end plate 37 of the socket 3. By the expansion / contraction restraining member 34, the distance D between the distal end of the pipe head 5 and the end plate 37 of the socket 3 is kept at a maximum.

[0028] As shown in FIGS. 2, 6 and 7, the expansion / contraction restraining member 34 is a cylindrical member made of metal and has a recessed portion 39 in the inner circumference, and is divided into a number (for example, four in FIG. 6) of expansion / contraction restraining pieces 40 in an arcuate circumferential direction. The end portions of one and the other of the adjacent expansion / contraction restraining pieces 40 are connected to each other in the circumferential direction through a connecting plate 42 and a number of connecting bolts 43. That is, a plurality of bolt holes 44 are formed in the connection. The plate 42 and a connecting bolt hole 45 are formed in the end portion of the expansion / contraction restraining piece 40. Then, by inserting the connecting bolt 43 into the bolt hole 44 of the connecting plate 42 and screwing it into the connecting bolt hole 45 of the expansion / contraction restraining piece 40, the end portion of one of the expansion / contraction restraining pieces 40 and the end portion of the other expansion / contraction restraining piece 40 are connected together.

[0029] In addition, in each expansion / contraction restraining piece 40, a centering screw hole 47 is formed that penetrates the inner peripheral surface and the outer peripheral surface. A centering screw 48 that aligns the center of the expansion / contraction restraining member 34 with the center of the pipe 2 is screwed into each centering screw hole 47. By rotating each centering screw 48, the expansion / contraction restraining member 34 is moved in the radial direction of the pipe.

[0030] Note that while the inner diameter of the expansion / contraction restraining member 34 is the same as or nearly the same as the inner diameter of the pipe head 5, the outer diameter of the expansion / contraction restraining member 34 is larger than the outer diameter of the pipe head 5. As a result, as shown in FIG. 2 , an end face 34a of the expansion / contraction restraining member 34 protrudes outwardly in the pipe axial direction as a step in the pipe radial direction from the outer periphery of the pipe head 5 over the entire circumference.

[0031] As shown in FIGS. 2 and 8 , the bending restraining member 35 is a member for restraining the socket 3 and the pipe head 5 in the bending direction C and is movably positioned between the inner periphery of the socket 3 and the outer periphery of the pipe 5 in the range between the distal end of the pipe head 5 and the protrusion of the nail 15. This bending restraining member 35 is a ring-shaped member made of metal and is divided into a plurality (for example, three in FIG. 8 ) of bending restraining pieces 60 in the circumferential direction. Next, a method for connecting pipes 2 and 4 in the connection of pipe 1 described above will be explained.

[0032] As shown in Fig. 9, in advance, the ring body 31, the sealing washer 19, and the press ring 22 are externally connected to the first tube 4. Then, the ring press member 9 and the lock ring 8 are inserted into the lock ring groove 7 of the second tube 2. After that, as shown in Fig. 3, the width 12 of the cut-out portion 11 of the lock ring 8 is expanded by the expander 13 to expand the diameter of the lock ring 8. Then, as shown in Fig. 9, an L-shaped diameter expansion retainer 58 is inserted into the cut-out portion 11 of the lock ring 8, and the expander 13 is removed to hold the lock ring 8 in a state in which the diameter is expanded.

[0033] Then, as shown in Figure 10, the pipe head 5 is inserted into the socket 3 so that the pipe protrusion 15 passes from the end of the socket opening 3 toward the back of the socket 3 relative to the lock ring 8. At this moment, the lock ring 8 is maintained in a diametrically expanded state by the diametrically expanded retainer 58, and the rod protrusion 15 easily passes through the lock ring 8. Then, as shown in Figure 11, the diameter expansion retainer 58 is removed to reduce the diameter of the locking ring 8. As a result, the locking ring 8 holds the outer circumference of the rod 5.

[0034] Then, as shown in Figure 12, with the tube protrusion 15 engaging with the lock ring 8, the ring body 31 is moved in the direction of the tube axis to be pressed through the end of the socket opening 3, between the inner peripheral surface of the socket 3 and the outer peripheral surface of the tube head 5, and positioned between the inner peripheral surface of the socket protrusion 18 and the outer peripheral surface of the tube head 5.

[0035] As a result, the main body part 32 moves the ring body 31 of the pipe head 5 in the radial direction of the pipe so that the deviation in the radial direction of the pipe between the axis of the first pipe 4 and the axis of the second pipe 2 is reduced. For this reason, the axis of the first pipe 4 coincides with the axis of the second pipe 2, so that the pipes 2 and 4 can be centered.

[0036] Then, as shown in Fig. 13, the sealing washer 19 is inserted into the sealing washer seating space 20 from the end portion of the socket opening 3, the pressing ring 22 is connected to the end portion of the socket opening 3 by means of a bolt 25 and a nut 26. And the bolt 25 and the nut 26 are straightened until the adjacent portion 23 of the pressing ring 22 is against the end face of the socket opening 3. As a result, the sealing washer 19 is pressed into the sealing washer seating space 20 so as to be compressed in the radial direction of the pipe.

[0037] Then, as shown by an imaginary line in FIG. 13, first, a bending restraining piece 60 is inserted between the distal end of the pipe head 5 and the end plate 37 of the socket 3 between the inner periphery of the socket 3 and the outer periphery of the pipe head 5 in the range between the distal end of the pipe head 5 and the protrusion of the pipe head 15 so as to be positioned at the lower part in the pipe connection 1. Then, two bending restraining pieces 60 are respectively inserted between the distal end of the pipe head 5, and the end portion 37 of the socket 3 is inserted between the inner periphery of the socket 3 and the outer periphery of the socket 5 in the range between the distal end of the pipe head 5 and the protrusion of the pipe head 15 so as to be positioned in the circumferential direction.

[0038] Thus, by discarding the three pieces of bending restraint 60 in a ring shape, as shown in Figure 8, the bending restraint member 35 can be easily placed between the inner periphery of the socket 3 and the outer periphery of the head tube 5 in the area between the distal end 5 and the protrusion of the head tube 15, as shown in Figure 14.

[0039] Then, as shown in Figure 6, one of the expansion / contraction restraining pieces 40 is placed in the lower part of the socket 3, then a separate expansion / contraction restraining piece 40 is placed in each end part of the expansion / contraction restraining pieces 40 and the end parts. Of these, the corresponding expansion / contraction restraining pieces 40 are connected by the connecting plate 42 and the connecting bolts 43. In addition, a remaining expansion / contraction restraining piece 40 is placed in the upper part of the socket 3 and the end parts. The adjacent expansion / contraction restraining pieces 40 are connected by the connecting plate 42 and the connecting bolts 43.

[0040] By discarding the four expansion / contraction restraining pieces 40 in a cylindrical shape, as shown in Figure 2, the expansion / contraction restraining member 34 is positioned between the distal end of the tube head 5 and the end plate 37 of the socket 3. Thereafter, by turning each of the centering screws 48, the center of the expansion / contraction restraining member 34 is aligned with the center of the tube 2.

[0041] For example, when the center of the expansion / contraction restraining member 34 is lower than the center of the tube 2, the centering screw 48 may be rotated to raise the expansion / contraction restraining member 34 with the centering screw 48 until the center of the expansion / contraction restraining member 34 is aligned with the center of the tube 2.

[0042] By connecting the pipes 2 and 4 as described above, a bending restraining member 35 is formed between the inner periphery of the socket 3 and the outer periphery of the pipe 5 in the range between the distal end of the pipe head 5 and the pipe head protrusion 15, at the pipe connection 1 as shown in Fig. 2. Therefore, the socket 3 and the pipe head 5 are restrained in the bending direction C so that the bending rigidity of the pipe connection 1 is increased, thereby enabling sufficient bending rigidity to be achieved.

[0043] In addition, since the expansion / contraction restraining member 34 is provided between the distal end of the pipe head 5 and the end plate 37 of the socket 3, the pipe head 5 is prevented from moving in the direction of the pipe axis relative to the socket 3. Thus, it restricts the expansion / contraction of the pipe connection 1 and increases the bending rigidity of the pipe connection 1.

[0044] Furthermore, as a result of the connection of the bending restraining member 35 to an end face 34a of the expansion / contraction restraining member 34 in the pipe axis direction, the bending restraining member 35 prevents deflection in the pipe axis direction between the inner periphery of the socket 3 and the outer periphery of the pipe head 5 and slipping between the distal end of the pipe head 5 and the end plate 37 of the socket 3, as a result of which the bending restraining member 35 can be prevented from slipping from between the inner periphery of the socket 3 and the outer periphery of the socket 5 to between the distal end of the pipe head 5 and the end plate 37 of the socket 3.

[0045] Furthermore, as shown in Fig. 2, as a result of the attachment of the adjacent portion 23 of the press ring 22 to the end plate of the socket opening 3, the sealing gasket 19 cannot be pressed further toward the back of the socket with the press ring 22. As a result, since the sealing gasket 19 is not pressed against the back of the socket with excessive pressing force and the end portion of the sealing gasket 19 is not attached to the ring body 31, damage to the ring body 31 can be prevented.

[0046] Furthermore, as a result of the deflection preventing member 33 preventing deflection between the inner peripheral surface of the socket 3 and the main body portion 32 with the end portion of the deflection preventing member 33 being connected to the straight portion 17 of the inner peripheral surface in the socket 3, the main body portion 32 of the ring body 31 can be prevented from being deflected from between the inner peripheral surface of the socket protrusion 18 and the outer peripheral surface of the head 5 toward the end of the socket opening (in the separation direction A).

[0047] Although, in the embodiment described above, the expansion / contraction restraining member 34 is divided into four expansion / contraction restraining pieces 40, as shown in FIG. 6 6 , the number of pieces will not be limited to four pieces and may be any number other than four.

[0048] Although, in the embodiment described above, the bending restraining member 35 is divided into three bending restraining pieces 60, as shown in FIG. 8, the number of pieces is not limited to three and may be any number other than three. In addition, bending restraining pieces 60 adjacent to each other in the circumferential direction may be connected.

[0049] Although, in the embodiment described above, the expansion / contraction restraining member 34 and the bending restraining member 35 are provided as separate members in the pipe joint 1, as shown in FIG. 2, the expansion / contraction restraining member 34 and the bending restraining member 35 may be integrally formed, or may have an integral structure in which they are connected by a connecting member such as a bolt. Although, in the embodiment described above, the expansion / contraction restraining member 34 and the bending restraining member 35 are provided in the pipe joint 1 as shown in FIG. 2 , only the bending restraining member 35 can be provided without providing the expansion / contraction restraining member 34 .

Claims

Claims

1. A pipe fitting, comprising: a socket of a first pipe; a second pipe socket, the pipe head of the first pipe being inserted into the socket of the second pipe; a groove compatible with a lock ring formed in the inner periphery of the socket; a lock ring to be received in the groove of the lock ring; and an engaging portion formed in an outer periphery of the spigot, the engaging portion being formed in a position that is retracted in the direction of separation of the spigot from the distal end of the spigot. Wherein the engaging portion is engageable with the lock ring from the rear side of the socket in the direction of separation of the spigot to prevent the spigot from being separated from the socket. A bending restraining member is provided for restricting the socket and the spigot in a bending direction between the inner periphery of the socket and the outer periphery of the spigot in a range between the distal end of the spigot and the engaging portion. An expansion / contraction suppressing member is provided for restricting the socket and the spigot in the direction of the pipe axis between the distal end of the spigot and the rear end of the socket.The outer diameter of the expansion / contraction suppressing member is larger than the outer diameter of the spigot, an end face of the expansion / contraction suppressing member in the pipe axial direction protrudes outwardly as a step in the pipe radial direction from the outside; the circumference of the spigot between the distal end of the spigot and the end portion of the socket is defined therein. In a condition where the engaging portion engages with the locking ring from the back side of the socket in the direction of separating the spigot, the expansion / contraction suppressing member prevents the bending suppressing member from being deflected in the pipe axial direction from the socket and the outer periphery of the spigot and from slipping between the distal end of the spigot and the back end portion of the socket through the inner periphery.

2. The pipe connection according to claim 1, wherein the bending suppressing member is a ring-shaped member.

3. . The pipe connection according to claim 2, wherein the bending restraining member is divided into a plurality of arcuate bending restraining segments in a circumferential direction.

4. The pipe connection of claim 1, wherein the expansion / contraction restraining member is a ring-shaped member.

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