JP4664203B2 - Double pipe joint structure - Google Patents

Description

  The present invention relates to a double pipe joint structure in which an outer pipe and an inner pipe of a double pipe are branched by a joint pipe section.

  A conventional double pipe joint structure of this type is disclosed in Patent Document 1. As shown in FIG. 5, the joint structure of the double pipe 100 includes an end part of the double pipe 100 and an outer pipe joint pipe 110 and an inner pipe joint pipe 111 which are joint pipe parts connected to the end part. It is configured.

  The double pipe 100 includes an outer pipe 101 having a first flow path formed therein, an inner pipe 102 disposed inside the second pipe and having a second flow path formed therein, and the inner pipe 102 and the outer pipe 101. It is comprised from the connection rib 103 which connects between. An end portion on the branch side of the inner tube 102 is formed in an inner tube protruding portion 102 a that protrudes from the end of the outer tube 101.

  The outer pipe joint pipe 110 has a shape curved at a right angle, and one end side of the outer pipe joint pipe 110 is formed in the enlarged diameter portion 110a. One end side of the outer tube 101 is inserted into the enlarged diameter portion 110a. A brazing material 120 brazes the outer peripheral surface of the inserted outer tube 101 and the inner peripheral surface of the enlarged diameter portion 110 a of the outer tube joint tube 110. Further, a through hole 110 b is formed at a curved portion of the outer pipe joint pipe 110. The inner tube projecting portion 102a projects outward from the through hole 110b. Then, the first brazing material 121 brazes the outer peripheral surface of the inner pipe protruding portion 102 a and the peripheral surface of the through hole 110 b of the outer pipe joint pipe 110.

  One end side of the inner pipe joint pipe 111 is formed in the enlarged diameter part 111a. One end side of the inner tube protruding portion 102a is inserted into the enlarged diameter portion 111a. A space between the outer peripheral surface of the inserted inner pipe protrusion 102 a and the inner peripheral surface of the enlarged diameter portion 111 a of the inner pipe joint pipe 111 is brazed by the second brazing material 122.

  Next, the assembly process of the joint structure of the double pipe 100 will be described. The end of the outer pipe 101 of the double pipe 100 is inserted into the enlarged diameter part 110a of the outer pipe joint part 110, and the inner pipe protrusion 102a of the double pipe 100 is externally connected to the outside through the through hole 110b of the outer pipe joint part 110. Protrusively. Here, after winding the 2nd brazing material 121 around the outer peripheral surface of the inner pipe protrusion part 102a beforehand, the inner pipe protrusion part 102a is penetrated to the through-hole 110b. The end portion of the inner tube protruding portion 102a is inserted into the enlarged diameter portion 111a of the inner tube joint tube 111.

  Next, the 1st brazing material 120 is arrange | positioned in the state wound around the outer peripheral surface of the outer pipe | tube 101 in the upper position from the end of the enlarged diameter part 110a of the outer pipe joint pipe | tube 110. FIG. The 3rd brazing material 122 is arrange | positioned in the state wound around the outer peripheral surface of the inner pipe | tube protrusion part 102a above the end of the enlarged diameter part 111a of the inner pipe joint pipe | tube 111. FIG.

  Next, the temporarily assembled double pipe 100, outer pipe joint pipe 110, and inner pipe joint pipe 111 are arranged with the double pipe 100 side up and the outer pipe joint pipe 110 and inner pipe joint pipe 111 side down. To do.

Next, the three brazing materials 120, 121, 122 are heated with a burner or the like. Then, the 1st brazing material 120 arrange | positioned on the outer peripheral surface of the outer tube | pipe 101 fuse | melts, the molten brazing material 120 flows into between the inner peripheral surfaces of the outer tube enlarged diameter part 110a with dead weight, and solidifies after that. The second brazing material 121 disposed on the outer peripheral surface of the inner tube protruding portion 102a is melted, and the melted brazing material 121 flows into the peripheral surface of the through-hole 110b of the outer pipe joint portion 110 by its own weight, and then solidifies. To do. The third brazing material 122 disposed on the outer peripheral surface of the inner pipe projecting portion 102a is melted, and the melted brazing material 122 flows between itself and the inner peripheral surface of the inner pipe joint tube 111, and then solidifies. Thus, between the outer pipe 101 and the outer pipe joint part 110, between the inner pipe protrusion part 102a and the peripheral surface of the through hole 110b of the outer pipe joint pipe 110, and between the inner pipe protrusion part 102a and the inner pipe. It is completed by brazing each with the joint pipe 111.
JP 2004-245393 A

  However, in the conventional joint structure of the double pipe 100, the brazing between the outer peripheral surface of the inner pipe projecting portion 102a and the peripheral surface of the through hole 110b of the outer pipe joint portion 110 cannot be visually confirmed. There is a problem that the inspection process becomes troublesome.

  In addition, brazing between the outer pipe 101 and the outer pipe joint 110 and brazing between the inner pipe protrusion 102a and the inner pipe joint 111 can directly heat the brazing materials 120 and 122 by a burner. On the other hand, brazing between the peripheral surfaces of the inner tube protruding portion 102a and the through hole 110b of the outer tube joint portion 110 cannot directly heat the brazing material 121 by a burner. Accordingly, since the three brazing locations are not uniform in melting time, there is a problem that the influence on the base material is great and the quality stabilization is hindered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a double pipe joint structure that can simplify the brazing inspection process and can stabilize the quality with little influence on the brazing base material.

  The invention of claim 1 that achieves the above object comprises an outer tube having a first flow passage formed therein, and an inner tube disposed inside the outer tube and having a second flow passage formed therein. In the double pipe joint structure in which the double pipe is branched by a joint pipe part, the double pipe is formed such that an end of the outer pipe is formed in an outer pipe enlarged diameter part, and an end of the inner pipe is the outer pipe. The joint pipe part has an outer pipe joint pipe in which a through hole is formed, and one end side of the outer pipe joint pipe is inserted into the outer pipe diameter-expanded part. In addition, the protruding portion of the inner pipe is guided to the outside through the through-hole, and a brazing material is provided between the outer pipe joint pipe and the outer pipe diameter-expanded section from the outer peripheral surface of the outer pipe joint pipe. Supply and flow between the inner peripheral surface of the outer pipe expanded diameter portion, between the outer peripheral surface of the inner pipe protruding portion and the peripheral surface of the through hole of the outer pipe joint pipe Wherein the by supplying the raw material from the outer peripheral surface of the inner tube protrusion poured between the peripheral surface of the through-holes are brazed respectively.

  Invention of Claim 2 is the joint structure of the double pipe of Claim 1, Comprising: The said joint piping part has an inner pipe joint pipe other than the said outer pipe joint pipe, The said inner pipe protrusion part of An end portion is formed in the inner pipe enlarged diameter portion, the inner pipe joint pipe is inserted into the inner pipe enlarged diameter section, and the inner pipe joint pipe is provided between the inner pipe enlarged diameter section and the inner pipe joint pipe. The brazing material is provided by brazing by supplying a brazing material from the outer circumferential surface of the inner pipe and pouring it between the inner circumferential surface of the inner pipe expanded portion.

  According to the invention of claim 1, in the state where the double pipe and the joint pipe part are temporarily assembled, all the places where the brazing material is disposed are outside, and the brazing material can be melted by heating from the outside. The brazing state can be confirmed by visual observation, and since the brazing material can be directly heated by a burner at all locations, the melting conditions are all the same, so the melting time of the brazing material becomes uniform. As described above, the brazing inspection process can be simplified and the quality can be stabilized.

  According to the invention of claim 2, in addition to the effect of the invention of claim 1, the tip of the outer pipe joint pipe is placed in the outer pipe enlarged diameter portion while the inner pipe passing through the inside of the outer pipe joint pipe is passed through the through hole. The double pipe and the joint piping part can be temporarily assembled by inserting and inserting one end side of the inner pipe joint pipe into the inner pipe enlarged diameter part of the inner pipe projecting part projecting outward from the through hole. Therefore, the temporary assembly of the double pipe and the joint pipe can be facilitated. If the brazing process is performed after the temporary assembly is completely completed, the assembly of the joint structure is completed, and it is not necessary to intervene the process of processing the joint piping part after the temporary assembly process, so that the assembly operation can be simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a first embodiment of the present invention. FIG. 1 is a sectional view of a joint structure on the female side of a double pipe, and FIG. 2 is an enlarged sectional view of an essential part thereof.

  As shown in FIG. 1, the joint structure on the female side of the double pipe 1 includes an end portion of the double pipe 1 and a joint pipe portion 10 connected to the end portion.

  The double pipe 1 includes an outer pipe 2 having a first flow passage formed therein, an inner pipe 3 disposed inside the second flow passage and formed therein, an inner pipe 3 and an outer pipe 2. The connecting rib 4 is arranged on a concentric shaft and connects between the inner tube 3 and the outer tube 2. An end portion on the branch side of the outer tube 2 is formed in the outer tube expanded diameter portion 2a having a larger diameter than other portions. A tapered flange 2c for holding the melted brazing material is formed at the tip of the outer pipe diameter-enlarged portion 2a. An end portion on the branch side of the inner tube 3 is formed in an inner tube protruding portion 3 a protruding from the end of the outer tube 2. An end portion of the inner tube protruding portion 3a is formed in the inner tube enlarged diameter portion 3b. A tapered flange portion 3c for holding the molten brazing material is formed at the tip of the inner pipe expanded diameter portion 3b. The connecting rib 4 is removed so that only the inner tube 3 extends from the end of the outer tube expanded portion 2a, and the slit 2b (by cutting between the inner surface of the outer tube expanded portion 2a and the connecting rib 4 is cut). 2) is formed.

  The joint piping part 10 is comprised from the outer flange joint pipe 11, the inner pipe joint pipe 12, and the joint flange part 13 which supports these other end sides.

  The outer pipe joint pipe 11 has a shape curved at a right angle, and one end side thereof is inserted into the outer pipe enlarged diameter portion 2a. The outer peripheral surface of the inserted outer pipe joint tube 11 and the inner peripheral surface of the outer pipe enlarged diameter portion 2a are joined by a first brazing portion 20. A through hole 11 a is formed in the curved portion of the outer pipe joint pipe 11. The inner pipe enlarged diameter part 3b of the inner pipe protruding part 3a protrudes from the through hole 11a. The outer peripheral surface of the inner pipe enlarged diameter portion 3 b and the peripheral surface of the through hole 11 a of the outer pipe joint pipe 11 are joined by the second brazing portion 21.

  The inner pipe joint pipe 12 has a shape that is distorted at a right angle, and one end of the inner pipe joint pipe 12 is inserted into the inner pipe expanded diameter portion 3b. The outer peripheral surface of the inserted inner pipe joint pipe 12 and the inner peripheral surface of the inner pipe enlarged diameter portion 3b are joined by a third brazing portion 22.

  The joint flange portion 13 has holes 13a and 13b at two locations, and the other end sides of the outer pipe joint pipe 11 and the inner pipe joint pipe 12 are inserted into the holes 13a and 13b, respectively. The other end sides of the outer pipe joint pipe 11 and the inner pipe joint pipe 12 are respectively formed in the female connection portions 11b and 12a by pipe deformation processing. Further, the other end sides of the outer pipe joint pipe 11 and the inner pipe joint pipe 12 are fixed to the joint flange portion 13 by the caulking portions 23, 23 and the like.

  Next, the assembly process of the joint structure of the double pipe 1 will be described. One end side of the outer pipe joint pipe 11 is inserted into the outer pipe enlarged diameter part 2 a of the double pipe 1, and the inner pipe projection part 3 a of the double pipe 1 is projected outside from the through hole 11 a of the outer pipe joint pipe 11. To do. Thereafter, a tapered flange portion 3c is formed by a punch or the like at the tip of the inner tube enlarged diameter portion 3b of the inner tube protruding portion 3a. One end side of the inner pipe joint pipe 32 is inserted into the inner pipe enlarged diameter part 3b of the projected inner pipe projecting part 3a.

One end side of the inner pipe joint pipe 12 is inserted into the inner pipe enlarged diameter part 3b of the protruding inner pipe projecting part 3a.

  Next, the temporarily assembled double pipe 1 and the joint pipe section 10 are arranged with the joint pipe section 10 side facing up and the double pipe 1 side facing down.

  Next, the brazing material is arranged in three places where brazing is performed as follows. That is, as shown in FIG. 2, the first brazing material 20 a is arranged around the entire circumference by being wound around the outer peripheral surface of the outer pipe joint pipe 11 at a position above the end of the outer pipe enlarged diameter part 2 a. A second brazing material (not shown) is arranged around the entire circumference by winding the second brazing material (not shown) around the outer peripheral surface of the inner pipe joint portion 12 at a position above the outer pipe joint pipe 11. A third brazing material (not shown) is arranged around the entire circumference by winding it around the outer peripheral surface of the inner pipe joint pipe 12 at a position above the end of the inner pipe enlarged diameter portion 3b.

  Next, the three brazing materials 20a (not shown) and (not shown) are heated with a burner or the like. Then, the brazing material 20a disposed on the outer peripheral surface of the outer pipe joint pipe 11 is melted, and the melted brazing material 20a flows between itself and the inner peripheral surface of the outer pipe expanding portion 2a, and then solidifies. The brazing material (not shown) arranged on the outer peripheral surface of the inner pipe expanded diameter portion 3b is melted, and the molten brazing material flows into the peripheral surface of the through hole 11a of the outer pipe joint pipe 11 by its own weight, and thereafter Solidify. The brazing material (not shown) arranged on the outer peripheral surface of the inner pipe joint pipe 12 is melted, and the melted brazing material flows into the inner peripheral surface of the inner pipe expanded portion 3b by its own weight, and then solidifies.

  Thus, between the outer pipe 2 and the outer pipe joint pipe 11, between the inner pipe enlarged diameter part 3b and the peripheral surface of the through hole 11a of the outer pipe joint pipe 11, and the inner pipe enlarged diameter part 3b. When the inner pipe joint pipe 12 is brazed and joined by the brazing portions 20, 21, and 22, respectively, the process is completed.

  As described above, in the joint structure of the double pipe 1, the brazing material 20a, (not shown), (not shown) is arranged in a state where the double pipe 1 and the joint pipe portion 10 are temporarily assembled. Since all three places are outside, the brazing material 20a (not shown) and (not shown) can be melted by heating from the outside, so that the brazed state can be confirmed visually, and all the places Since the melting conditions are the same because the brazing material 20a (not shown) and (not shown) can be directly heated by a burner, the melting time of the brazing material 20a (not shown) and (not shown) Becomes uniform. As described above, the brazing inspection process can be simplified and the quality can be stabilized.

  In the first embodiment, one end side of the outer pipe joint pipe 11 is inserted into the outer pipe enlarged diameter part 2a while allowing the inner pipe protrusion 3a passing through the inside of the outer pipe joint pipe 11 to penetrate the through hole 11a. The double pipe 1 and the joint pipe part 10 can be temporarily assembled by inserting one end side of the inner pipe joint pipe 12 into the inner pipe enlarged diameter part 3b of the inner pipe projection part 3a projecting outside from the through hole 11a. Therefore, the temporary assembly of the double pipe 1 and the joint piping part 10 can be facilitated. After completing this temporary assembly process, if the brazing process is performed, the assembly of the joint structure is completed, and it is not necessary to intervene the machining process of the joint piping part 10 after the temporary assembly process, thus simplifying the assembly work. it can.

  In the first embodiment, the tapered flange portions 2c and 3c for holding the molten raw material are provided at the distal end of the outer tube expanded portion 2a and the distal end of the inner tube expanded portion 3b, respectively. , The certainty of brazing is improved.

  FIG. 3 is a cross-sectional view of a joint structure on the male side of a double pipe, showing a second embodiment of the present invention. As shown in FIG. 3, the joint structure on the male side of the double pipe is composed of an end portion of the double pipe 1 and a joint pipe portion 30 connected to the end portion.

  Since the double pipe 1 has the same configuration as that of the first embodiment, the same reference numerals are given to the same constituent portions to avoid redundant description.

  Similarly to the first embodiment, the joint pipe part 30 is composed of an outer pipe joint pipe 31, an inner pipe joint pipe 32, and a joint flange part 36 that supports the other end side thereof.

  The outer pipe joint pipe 31 has a shape curved at a right angle, and one end side thereof is inserted into the outer pipe enlarged diameter portion 2a. The outer peripheral surface of the inserted outer pipe joint pipe 31 and the inner peripheral surface of the outer pipe enlarged diameter part 2a are joined by a first brazing part 33. A through hole 31 a is formed in the curved portion of the outer pipe joint pipe 31. The inner tube protruding portion 3a protrudes from the through hole 31a. And the 2nd brazing part 34 has joined between the outer peripheral surface of the open pipe enlarged diameter part 3b of the inner pipe protrusion part 3a, and the peripheral surface of the through-hole 31a of the outer pipe joint pipe | tube 31. FIG.

  The inner pipe joint pipe 32 has a greatly distorted shape, and one end side thereof is inserted into the inner pipe enlarged diameter portion 3b. The outer peripheral surface of the inserted inner pipe joint pipe 32 and the inner peripheral surface of the inner pipe enlarged diameter portion 3b are joined by a third brazing portion 35.

  The joint flange portion 36 fixes the other end side of the outer pipe joint pipe 31 and the inner pipe joint pipe 32. The other end sides of the outer pipe joint pipe 31 and the inner pipe joint pipe 32 are respectively formed on the male connection portions 31b and 32a by pipe deformation processing.

  Next, the assembly process of the joint structure of the double pipe 1 will be described. One end side of the outer pipe joint pipe 31 is inserted into the outer pipe expanded diameter part 2 a of the double pipe 1, and the inner pipe protrusion part 3 a of the double pipe 1 protrudes outside from the through hole 31 a of the outer pipe joint pipe 31. To do. Thereafter, a tapered flange portion 3c is formed by a punch or the like at the tip of the inner tube expanded portion 3b of the inner tube protrusion 3a. One end side of the inner pipe joint pipe 32 is inserted into the inner pipe enlarged diameter part 3b of the projected inner pipe projecting part 3a.

  Next, the temporarily assembled double pipe 1 and the joint pipe part 30 are arranged with the joint pipe part 30 side upward and the double pipe 1 side downward.

  Next, a brazing material (not shown) is arranged as follows in three places where brazing is performed. In other words, the first brazing material is arranged around the entire circumference by being wound around the outer peripheral surface of the outer pipe joint pipe 31 at a position above the end of the outer pipe enlarged diameter portion 2a. The second brazing material is arranged around the entire circumference by winding the second brazing material around the outer peripheral surface of the inner pipe expanded diameter portion 3b at a position above the outer pipe joint pipe 31. The third brazing material is disposed around the entire circumference by winding the third brazing material around the outer peripheral surface of the inner pipe joint pipe 32 at a position above the end of the inner pipe enlarged diameter portion 3b.

  Next, the three brazing materials are heated with a burner or the like. Then, the 1st brazing material arrange | positioned on the outer peripheral surface of the outer pipe joint pipe | tube 31 fuse | melts, the molten brazing material flows between the inner peripheral surfaces of the outer pipe enlarged diameter part 2a with dead weight, and solidifies after that. The second brazing material disposed on the outer peripheral surface of the inner pipe expanded diameter portion 3b is melted, and the molten brazing material flows into the peripheral surface of the through hole 31a of the outer pipe joint pipe 31 by its own weight, and then solidifies. The third brazing material arranged on the outer peripheral surface of the inner pipe joint pipe 32 is melted, and the molten brazing material flows into the inner peripheral surface of the inner pipe enlarged diameter portion 3b by its own weight, and then solidifies.

  Thus, between the outer pipe 2 and the outer pipe joint pipe 31, between the inner pipe enlarged diameter part 3b and the peripheral surface of the through hole 31a of the outer pipe joint pipe 31, and the inner pipe enlarged diameter part 3b. If it braces between each with the inner pipe joint pipe 32, it will be completed.

  As described above, even in the joint structure of the double pipe 1, all the three places where the brazing material is disposed in the state where the double pipe 1 and the joint pipe portion 30 are temporarily assembled, as in the first embodiment. Since it is on the outside, the brazing state can be confirmed by visual observation, and the melting time of the brazing material becomes uniform. As described above, the brazing inspection process can be simplified and the quality can be stabilized.

  In the second embodiment, as in the first embodiment, one end side of the outer pipe joint pipe 31 is made to pass through the through hole 31a through the inner pipe protrusion 3a passing through the inside of the outer pipe joint pipe 31. The double pipe 1 is inserted by inserting one end side of the inner pipe joint pipe 32 into the inner pipe enlarged diameter part 3b of the inner pipe protruding part 3a which is inserted into the outer pipe enlarged diameter part 2a and protrudes to the outside from the through hole 31a. And the joint piping part 30 can be temporarily assembled. Therefore, the temporary assembly of the double pipe 1 and the joint piping part 30 can be facilitated. After completing this temporary assembly process, if the brazing process is performed, the assembly of the joint structure is completed, and it is not necessary to intervene the machining process of the joint piping part 30 after the temporary assembly process, thus simplifying the assembly work. it can.

  FIG. 4 shows a third embodiment of the present invention, and FIG. 4 is a sectional view of the joint structure on the female side of the double pipe. As shown in FIG. 4, the joint structure on the female side of the double pipe 1 includes an end portion of the double pipe 1 and a joint pipe portion 40 connected to the end portion.

  Similar to the first embodiment, the double pipe 1 includes an outer pipe 2 in which a first flow path is formed, and an inner pipe which is disposed inside and has a second flow path formed therein. 3 and a connecting rib 4 that connects the inner tube 3 and the outer tube 2. An end of the outer tube 2 on the branch side is formed in the outer tube enlarged diameter portion 2a. A slit (particularly, no reference numeral) is formed by cutting between the inner surface of the outer pipe enlarged diameter portion 2a and the connecting rib. One end side of the outer pipe joint pipe 41 can be inserted using this slit. A tapered flange 2c for holding the molten brazing material is formed at the distal end of the outer tube diameter-enlarged portion 2a.

  An end portion on the branch side of the inner tube 3 is formed in an inner tube protruding portion 3 a protruding from the end of the outer tube 2. The inner tube protruding portion 3a is longer than that of the first embodiment and is bent at a substantially right angle in the middle, and the other end of the curve is supported by a joint flange portion 42 described below. That is, unlike the first embodiment, the distal end side of the inner pipe enlarged diameter portion 3a also serves as an inner pipe joint pipe.

  Unlike the first embodiment, the joint pipe part 40 is composed of an outer pipe joint pipe 41 and a joint flange part 42 that supports the other end side and the other end side of the inner pipe protruding part 3a.

  The outer pipe joint pipe 41 has a shape that is distorted at a right angle, and one end of the outer pipe joint pipe 41 is inserted into the outer pipe enlarged diameter portion 2a. The outer peripheral surface of the inserted outer pipe joint pipe 41 and the inner peripheral surface of the outer pipe enlarged diameter part 2a are joined by a first brazing part 43. A through hole 41 a is formed in the curved portion of the outer pipe joint pipe 41. The inner tube protruding portion 3a protrudes from the through hole 41a. The outer peripheral surface of the inner pipe protrusion 3 a and the peripheral surface of the through hole 41 a of the outer pipe joint pipe 41 are joined by a second brazing part 44.

  The joint flange portion 42 has holes 42a and 42b at two locations, and the other end sides of the outer pipe joint pipe 41 and the inner pipe protrusion 3a are inserted into the holes 42a and 42b, respectively. The other end sides of the outer pipe joint pipe 41 and the inner pipe protruding portion 3a are respectively formed in the female connection portions 41b and 3d by pipe deformation processing. Further, the other end sides of the outer pipe joint pipe 41 and the inner pipe protruding portion 3a are fixed to the joint flange portion 42 by caulking portions 45, 45 and the like.

  Next, the assembly process of the joint structure of the double pipe 1 will be described. One end side of the outer pipe joint pipe 41 is inserted into the outer pipe enlarged diameter part 2 a of the double pipe 1, and the inner pipe protrusion part 3 a of the double pipe 1 protrudes outside from the through hole 41 a of the outer pipe joint pipe 41. To do.

  Next, the temporarily assembled double pipe 1 and the joint pipe section 40 are arranged with the joint pipe section 40 side facing up and the double pipe 1 side facing down.

  Next, a brazing material (not shown) is arranged as follows in two places to be brazed. That is, the first brazing material is arranged around the entire circumference by being wound around the outer peripheral surface of the outer pipe joint pipe 41 at a position above the end of the outer pipe enlarged diameter portion 2a. The second brazing material is placed around the entire circumference by wrapping the second brazing material around the outer peripheral surface of the inner pipe protruding portion 3a at a position above the outer pipe joint pipe 41.

  Next, the two brazing materials are heated with a burner or the like. Then, the brazing material arranged on the outer peripheral surface of the outer pipe joint pipe 41 is melted, and the melted brazing material flows into the inner peripheral surface of the outer pipe enlarged diameter portion 2a by its own weight, and then solidifies. The brazing material disposed on the outer peripheral surface of the inner pipe enlarged diameter portion 3a is melted, and the melted brazing material flows into the peripheral surface of the through hole 41a of the outer pipe joint pipe 41 by its own weight, and then solidifies.

  In this way, when the brazing is performed between the outer pipe 2 and the outer pipe joint pipe 41 and between the inner pipe protrusion 3a and the peripheral surface of the through hole 41a of the outer pipe joint pipe 41, the process is completed.

  As described above, in the joint structure of the double pipe 1, in the state where the double pipe 1 and the joint pipe portion 40 are temporarily assembled, all the two places where the brazing material is disposed are outside, and by heating from the outside, Since the brazing material can be melted, the state of brazing can be confirmed visually, and since the brazing material can be directly heated by a burner at all locations, the melting conditions are the same, so the melting time of the brazing material is uniform. become. As described above, the brazing inspection process can be simplified and the quality can be stabilized. In addition, the third embodiment has an advantage that only two brazing points are required as compared with the first embodiment.

  Of course, the same configuration as that of the third embodiment can be applied to the joint structure on the male side.

  In the first to third embodiments, the case where the brazing process is performed by using a row has been described, but it is needless to say that the process can be performed by a feeding row. In the case of a feed row, the molten brazing material is flown in the direction of the flow of the flow in FIGS.

It is sectional drawing of the joint structure by the side of the female side of the double pipe which shows 1st Embodiment of this invention. FIG. 1 is an enlarged cross-sectional view of a main part of a joint structure, showing a first embodiment of the present invention. It is sectional drawing of the joint structure of the male side of a double pipe | tube which shows 2nd Embodiment of this invention. It is sectional drawing of the joint structure by the side of the female side of the double pipe which shows 3rd Embodiment of this invention. It is sectional drawing of the joint structure of the double pipe of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double pipe 2 Outer pipe 2a Outer pipe enlarged diameter part 3 Inner pipe 3a Inner pipe protrusion part 3b Inner pipe enlarged diameter part 10 Joint piping part 11 Outer pipe joint pipe 11a Through hole 12 Inner pipe joint pipe 30 Joint piping part 31 Outside Pipe joint pipe 31a Through hole 32 Inner pipe joint pipe 40 Joint pipe part 41 Outer pipe joint pipe 41a Through hole

Claims (2)

A double pipe having an outer pipe (2) having a first flow path formed therein and an inner pipe (3) disposed inside the outer pipe (2) and having a second flow path formed therein. In the joint structure of the double pipe (1) where (1) is branched by the joint pipe part (10, 30, 40),
In the double pipe (1), an end of the outer pipe (2) is formed in an outer pipe enlarged diameter part (2a), and an end of the inner pipe (3) is an end of the outer pipe (2). Formed in the protruding inner tube (3a),
The joint pipe part (10, 30, 40) has an outer pipe joint pipe (11, 31, 41) in which a through hole (11a, 31a, 41a) is formed,
One end side of the outer pipe joint pipe (11, 31, 41) is inserted into the outer pipe enlarged diameter part (2a), and the inner pipe protrusion (3a) passes through the through hole (11a, 31a, 41a). Penetrated to the outside,
The brazing material (20a) is supplied from the outer peripheral surface of the outer pipe joint pipe (11, 31, 41) between the outer pipe joint pipe (11, 31, 41) and the outer pipe diameter-expanded portion (2a). Then, it flows between the inner peripheral surface of the outer pipe enlarged diameter part (2a), and the outer peripheral surface of the inner pipe projecting part (3a) and the through-hole ( 11a, 31a, 41a) between the peripheral surfaces of the through-holes (11a), (31a, 41a) by supplying brazing material from the outer peripheral surface of the inner tube protrusion (3a). The joint structure of the double pipe (1), which is brazed by being poured into the pipe. The joint structure of the double pipe (1) according to claim 1,
The joint pipe section (10, 30) has an inner pipe joint pipe (12, 32) in addition to the outer pipe joint pipe (11, 31).
An end of the inner pipe projecting portion (3a) is formed in the inner pipe enlarged diameter portion (3b), and the inner pipe joint pipe (12, 32) is inserted into the inner pipe enlarged diameter portion (3b), A brazing material is supplied from the outer peripheral surface of the inner pipe joint pipe (12, 32) between the inner pipe diameter-expanded part (3b) and the inner pipe joint pipe (12, 32). The joint structure of the double pipe (1), which is brazed by pouring between the inner peripheral surface of (3b).

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