阅读说明：本技术 一种用于燃气供气的双壁管结构及其装配方法 (Double-wall pipe structure for gas supply and assembling method thereof ) 是由 梅加化 于 2020-06-29 设计创作，主要内容包括：本发明公开了一种用于燃气供气的双壁管结构及其装配方法,包括：内管；外管,套设于所述内管外,所述外管的管壁上沿其周向设置有至少两个通孔；套筒,固设于所述外管上,且与所述通孔对应设置,所述套筒的内壁设置有内螺纹；螺栓,由外向内依次穿过所述套筒和所述通孔,并抵接在所述内管上,所述螺栓上设置有与所述内螺纹配合的外螺纹,以使所述螺栓与所述套筒螺纹连接,以将所述外管支撑在所述内管外部。该发明提供一种结构简单,组装方便的双壁管结构。(The invention discloses a double-wall pipe structure for gas supply and an assembly method thereof, wherein the double-wall pipe structure comprises the following components: an inner tube; the outer pipe is sleeved outside the inner pipe, and at least two through holes are formed in the pipe wall of the outer pipe along the circumferential direction of the outer pipe; the sleeve is fixedly arranged on the outer pipe and corresponds to the through hole, and an inner thread is arranged on the inner wall of the sleeve; and the bolt sequentially penetrates through the sleeve and the through hole from outside to inside and is abutted to the inner pipe, and an external thread matched with the internal thread is arranged on the bolt, so that the bolt is in threaded connection with the sleeve, and the outer pipe is supported outside the inner pipe. The invention provides a double-wall pipe structure which is simple in structure and convenient to assemble.)

1. A double-walled tube structure for gas supply, comprising:

an inner tube (10);

the outer pipe (20) is sleeved outside the inner pipe (10), and at least two through holes (21) are formed in the pipe wall of the outer pipe (20) along the circumferential direction of the pipe wall;

the sleeve (40) is fixedly arranged on the outer pipe (20) and is arranged corresponding to the through hole (21), and an internal thread is arranged on the inner wall of the sleeve (40);

the bolt (30) sequentially penetrates through the sleeve (40) and the through hole (21) from outside to inside and abuts against the inner pipe (10), and an external thread matched with the internal thread is arranged on the bolt (30) so that the bolt (30) is in threaded connection with the sleeve (40) and the outer pipe (20) is supported outside the inner pipe (10).

2. The double-walled tube structure of claim 1, wherein:

the tail end of the bolt (30) is provided with an elastic head (31), and the elastic head (31) is abutted to the inner pipe (10).

3. The double-walled tube structure of claim 1, wherein:

sleeve (40) with the one end that outer tube (20) are connected is provided with arc surface (41), arc surface (41) can with the outer wall laminating of outer tube (20).

4. The double-walled tube structure of claim 1, wherein:

the inner pipe (10) comprises a first inner pipe straight pipe (11), an inner pipe bent pipe (12) and a second inner pipe straight pipe (13) which are sequentially connected;

the outer pipe (20) comprises a first outer pipe straight pipe (22), an outer pipe bent pipe (23) and a second outer pipe straight pipe (24) which are sequentially connected;

the first outer pipe straight pipe (22) is arranged outside the first inner pipe straight pipe (11), the outer pipe bent pipe (23) is arranged outside the inner pipe bent pipe (12), and the second outer pipe straight pipe (24) is arranged outside the second inner pipe straight pipe (13);

the tail ends of the first inner pipe straight pipe (11) and the first outer pipe straight pipe (22) are connected with a first flange (60); the tail ends of the second inner pipe straight pipe (13) and the second outer pipe straight pipe (24) are connected with a second flange (70).

5. The double-walled pipe structure of claim 4, wherein:

the double-walled tube structure further includes:

a bellows segment (80) connected to the second flange (70);

the bellows segment (80) comprises:

the corrugated pipe (81) and a third flange (82) and a fourth flange (83) which are respectively arranged at two ends of the corrugated pipe (81), wherein the third flange (82) is connected with the second flange (70).

6. The double-walled pipe structure of claim 5, wherein:

the bellows segment (80) further comprises:

and the sleeve (84) is arranged outside the corrugated pipe (81) and used for protecting the corrugated pipe (81), and one end of the sleeve (84) is fixed on the third flange (82) or the fourth flange (83).

7. The double-walled pipe structure of claim 4, wherein:

the first outer pipe straight pipe (22) is connected with the first flange (60) through a first half pipe (221) and a second half pipe (222), and the first half pipe (221) and the second half pipe (222) can be combined into a pipe;

the second outer pipe straight pipe (24) is connected with the second flange (70) through a third half pipe (241) and a fourth half pipe (242), and the third half pipe (241) and the fourth half pipe (242) can be combined into a pipe.

8. The double-walled pipe structure of claim 7, wherein:

the two ends of the inner pipe elbow (12) are longer than the two ends of the outer pipe elbow (23).

9. Double-walled pipe construction according to claim 1, characterized in that a washer (50) is padded between the bolt head of the bolt (30) and the sleeve (40).

10. A method of assembling a double wall tubular structure according to claim 8, comprising the steps of:

a. sleeving the outer pipe elbow (23) outside the inner pipe elbow (12);

b. placing the sleeve (40) over the through hole (21) on the outer tube elbow (23);

c. after the bolt (30) is sequentially inserted into the sleeve (40) and the through hole (21), the bolt is abutted against the inner pipe bent pipe (12), and the bolt (30) is screwed;

d. bending the inner pipe elbow (12) and the outer pipe elbow (23) to a required angle;

e. respectively welding the first inner pipe straight pipe (11) and the second inner pipe straight pipe (13) with two ends of the inner pipe bent pipe (12);

f. sleeving the first outer pipe straight pipe (22) outside the first inner pipe straight pipe (11);

g. placing the sleeve (40) over the through hole (21) on the first outer straight tube (22);

h. the bolt (30) is sequentially inserted into the sleeve (40) and the through hole (21), then is abutted against the first inner pipe straight pipe (11), and is screwed tightly;

i. sleeving the second outer pipe straight pipe (24) outside the second inner pipe straight pipe (13);

j. -placing the sleeve (40) on the through hole (21) on the second outer tube straight tube (24);

k. the bolt (30) is sequentially inserted into the sleeve (40) and the through hole (21), then is abutted against the second inner pipe straight pipe (13), and is screwed tightly;

l, welding the tail end of the first inner pipe straight pipe (11) with the first flange (60);

m, trimming the lengths of the first half pipe (221) and the second half pipe (222) according to the distance between the first outer pipe straight pipe (22) and the first flange (60), and welding the first outer pipe straight pipe (22) and the first flange (60) through the first half pipe (221) and the second half pipe (222);

n, welding the tail end of the second inner pipe straight pipe (13) with the second flange (70);

and o, trimming the lengths of the third half pipe (241) and the fourth half pipe (242) according to the distance between the second outer pipe straight pipe (24) and the second flange (70), and welding the second outer pipe straight pipe (24) and the second flange (70) through the third half pipe (241) and the fourth half pipe (242).

Technical Field

The invention relates to the technical field of gas supply, in particular to a double-wall pipe structure for gas supply and an assembly method thereof.

Background

Because of the safe gas supply requirements of fuel gases such as hydrogen, natural gas and the like, a double-wall pipe is generally adopted for supplying gas, namely, a gas supply pipeline is arranged in a ventilation pipe, and an independent mechanical exhaust fan is arranged in the space between the gas supply pipeline and the ventilation pipe, so that forced ventilation is realized, and the safety of a gas supply system is ensured. The existing double-wall pipe has complex structure and installation process and high cost, and is not suitable for double-wall pipelines with the diameter of less than 20 mm.

Disclosure of Invention

The invention aims to provide a double-wall pipe structure for gas supply and an assembly method thereof, and aims to solve the problems of complex structure and installation process and high cost of the double-wall pipe for gas supply in the background technology.

In order to achieve the purpose, the invention adopts the following technical scheme:

a double-walled tube structure for gas supply, comprising:

an inner tube;

the outer pipe is sleeved outside the inner pipe, and at least two through holes are formed in the pipe wall of the outer pipe along the circumferential direction of the outer pipe;

the sleeve is fixedly arranged on the outer pipe and corresponds to the through hole, and an inner thread is arranged on the inner wall of the sleeve;

and the bolt sequentially penetrates through the sleeve and the through hole from outside to inside and is abutted to the inner pipe, and an external thread matched with the internal thread is arranged on the bolt, so that the bolt is in threaded connection with the sleeve, and the outer pipe is supported outside the inner pipe.

Optionally, the end of the bolt is provided with an elastic head, and the elastic head abuts against the inner tube.

Optionally, one end of the sleeve connected with the outer pipe is provided with an arc surface, and the arc surface can be attached to the outer wall of the outer pipe.

Optionally, the inner pipe comprises a first inner pipe straight pipe, an inner pipe bent pipe and a second inner pipe straight pipe which are connected in sequence;

the outer pipe comprises a first outer pipe straight pipe, an outer pipe bent pipe and a second outer pipe straight pipe which are sequentially connected;

the first outer pipe straight pipe is arranged outside the first inner pipe straight pipe, the outer pipe bent pipe is arranged outside the inner pipe bent pipe, and the second outer pipe straight pipe is arranged outside the second inner pipe straight pipe;

the tail ends of the first inner pipe straight pipe and the first outer pipe straight pipe are connected with a first flange; the tail ends of the second inner pipe straight pipe and the second outer pipe straight pipe are connected with a second flange.

Optionally, the double-walled tube structure further includes:

the corrugated pipe section is connected with the second flange;

the bellows section comprises:

the corrugated pipe, a third flange and a fourth flange are arranged at two ends of the corrugated pipe respectively, and the third flange is connected with the second flange.

Optionally, the bellows section further comprises:

and the sleeve is arranged outside the corrugated pipe and used for protecting the corrugated pipe, and one end of the sleeve is fixed on the third flange or the fourth flange.

Optionally, the first outer pipe straight pipe and the first flange are connected through a first half pipe and a second half pipe, and the first half pipe and the second half pipe can be combined into a pipe;

the second outer pipe straight pipe and the second flange are connected through a third half pipe and a fourth half pipe, and the third half pipe and the fourth half pipe can be combined into a pipe.

Optionally, both ends of the inner pipe elbow are longer than both ends of the outer pipe elbow.

Optionally, a gasket is padded between the bolt head of the bolt and the sleeve.

The invention also provides an assembly method for the double-wall pipe structure, which comprises the following steps:

a. sleeving the outer pipe bent pipe outside the inner pipe bent pipe;

b. placing the sleeve over the through-hole on the outer tube elbow;

c. after the bolt sequentially penetrates through the sleeve and the through hole, the bolt is abutted against the inner pipe bent pipe and is screwed tightly;

d. bending the inner pipe bent pipe and the outer pipe bent pipe together to a required angle;

e. respectively welding the first inner pipe straight pipe and the second inner pipe straight pipe with two ends of the inner pipe bent pipe;

f. sleeving the first outer pipe straight pipe outside the first inner pipe straight pipe;

g. placing the sleeve over the through hole on the first outer straight tube;

h. after the bolt sequentially penetrates through the sleeve and the through hole, the bolt is abutted against the first inner pipe straight pipe and is screwed tightly;

i. sleeving the second outer pipe straight pipe outside the second inner pipe straight pipe;

j. placing the sleeve over the through hole on the second outer tube straight tube;

k. after the bolt sequentially penetrates through the sleeve and the through hole, the bolt is abutted against the second inner pipe straight pipe and is screwed tightly;

welding the tail end of the first inner pipe straight pipe with the first flange;

m, trimming the lengths of the first half pipe and the second half pipe according to the distance between the first outer pipe straight pipe and the first flange, and welding the first outer pipe straight pipe and the first flange through the first half pipe and the second half pipe;

n, welding the tail end of the second inner pipe straight pipe with the second flange;

and o, trimming the lengths of the third half pipe and the fourth half pipe according to the distance between the second outer pipe straight pipe and the second flange, and welding the second outer pipe straight pipe and the second flange through the third half pipe and the fourth half pipe.

The invention has the advantages that: be provided with the through-hole on the outer tube, the bolt passes sleeve and through-hole, and sleeve and bolt screw-thread fit, the terminal butt of bolt is on the inner tube, screws up the bolt and can fix the outer tube in the outside of inner tube, forms double-walled tube structure, and overall structure is simple, and the equipment is convenient, greatly reduced the cost of double-walled tube.

Drawings

FIG. 1 is a perspective view of a double wall tubular structure in an embodiment of the invention;

FIG. 2 is a first exploded view of the double wall tubular structure of FIG. 1 in accordance with the present invention;

FIG. 3 is a schematic cross-sectional view of section A-A of the double wall tubular structure of FIG. 1 in accordance with the present invention;

FIG. 4 is an exploded view of the bolt, elastomeric head, washer and sleeve of an embodiment of the present invention;

FIG. 5 is a second exploded view of the double wall tubular structure of FIG. 1 in accordance with the present invention;

FIG. 6 is an exploded view of a bellows segment in an embodiment of the present invention;

FIG. 7 is a schematic view of the assembly of the inner tube elbow and the outer tube elbow in an embodiment of the invention.

In the figure:

100. a double wall tubular structure; 10. an inner tube; 20. an outer tube; 30. a bolt; 40. a sleeve; 50. a gasket; 60. A first flange; 70. a second flange; 80. a bellows section;

11. a first inner pipe straight pipe; 12. bending the inner pipe; 13. a second inner pipe straight pipe; 21. a through hole; 22. a first outer tube straight tube; 23. bending the outer pipe; 24. a second outer tube straight tube; 31. an elastic head; 41. a circular arc surface; 81. A bellows; 82. a third flange; 83. a fourth flange; 84. a sleeve;

221. a first half pipe; 222. a second half pipe; 241. a third half pipe; 242. a fourth half-tube.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

Referring to fig. 1, 2 and 3, a double-wall pipe structure 100 includes an inner pipe 10, an outer pipe 20, a bolt 30 and a sleeve 40. As shown in fig. 2, the outer pipe 20 is sleeved outside the inner pipe 10, the inner pipe 10 is used for ventilating gas, the outer pipe 20 is used as a ventilation pipe, and air flows in a space between the inner pipe 10 and the outer pipe 20 to perform a ventilation function.

As shown in fig. 3, at least two through holes 21 are formed in the wall of the outer tube 20 along the circumferential direction thereof, and the through holes 21 extend in the radial direction of the outer tube 20 to pass through the outside and the inside of the outer tube 20. The sleeve 40 is fixed on the outer tube 20 and is disposed corresponding to the through hole 21, the sleeve 40 is substantially cylindrical, an inner hole of the sleeve 40 is communicated with the through hole 21, so that the bolt 30 can pass through the inner hole of the sleeve 40 and the through hole 21, and an inner wall of the sleeve 40 is provided with an internal thread. The manner of fixedly connecting the sleeve 40 to the outer tube 20 may be, for example, welding. The bolt 30 sequentially penetrates through the sleeve 40 and the through hole 21 from outside to inside and abuts against the inner tube 10, and an external thread matched with the internal thread on the inner wall of the sleeve 40 is arranged on the bolt 30, so that the bolt 30 is in threaded connection with the sleeve 40, and the outer tube 20 can be supported outside the inner tube 10. The bolt 30 can be an M8 bolt, i.e., a bolt 30 with a diameter of 8 mm. Because the number of the through holes 21 is at least two, and the bolt 30 and the sleeve 40 are correspondingly arranged at each through hole 21, the number of the bolts 30 and the sleeves 40 is at least two, so that the outer pipe 20 can be supported and fixed outside the inner pipe 10, the outer pipe 20 cannot move randomly, the relative fixation between the inner pipe and the outer pipe is ensured, and the stability of the whole double-wall pipe structure 100 is ensured.

The double-wall pipe structure 100 is simple in structure, the installation between the inner pipe and the outer pipe can be completed only through a small number of parts, the double-wall pipe is formed, all parts are ready-made parts without field processing, and the double-wall pipe can be directly assembled, so that the installation difficulty is reduced, and the cost is reduced.

As mentioned above, the number of the through holes 21 is at least two, but may be a plurality, such as three, four or five, etc., and each through hole 21 is fitted with one bolt 30 and the sleeve 40. In the embodiment shown in fig. 3, there are three through holes 21, and the three through holes 21 are uniformly distributed on the outer tube 20 along the circumferential direction of the outer tube 20.

As shown in fig. 3, the through-hole 21 has a bore diameter between the inner and outer diameters of the sleeve 40 so that the bolt 30 can pass from the inner bore of the sleeve 40 into the through-hole 21. Preferably, the diameter of the through hole 21 is slightly larger than the inner diameter of the sleeve 40, but not too large, so as to ensure that the bolt 30 can pass through the through hole 21, and the through hole 21 is not too large to cause the strength of the outer tube 20 to be reduced.

With continued reference to fig. 3, the end of the bolt 30 is provided with an elastic head 31, and the elastic head 31 abuts against the inner tube 10, so that the contact between the bolt 30 and the inner tube 10 is soft contact, and the inner tube 10 can be protected. Specifically, as shown in fig. 4, a clamping column is disposed at the end of the bolt 30, a clamping hole is disposed at the top end of the elastic head 31, and the clamping column of the bolt 30 is clamped into the clamping hole of the elastic head 31, so that the elastic head 31 can be mounted at the end of the bolt 30. The elastic head 31 may be made of plastic or rubber.

Referring to fig. 3 and 4, an arc surface 41 is disposed at one end of the sleeve 40 abutting against the outer tube 20, and the arc surface 41 can be attached to the outer wall of the outer tube 20, so as to prevent a gap from being formed at the joint between the outer tube 20 and the sleeve 40 and prevent air leakage. In addition, when the sleeve 40 is welded to the outer tube 20 by welding, the fitting between the arc surface 41 and the outer wall of the outer tube 20 can also reduce the welding difficulty, so that the welding effect is better.

With continued reference to fig. 3 and 4, a gasket 50 is disposed between the bolt head of the bolt 30 and the sleeve 40 to increase the sealing performance between the bolt 30 and the sleeve 40 and prevent air leakage. The spacer 50 can also compensate the length error of the bolt 30, so that the bolt 30 can be tightly pressed on the inner pipe 10.

Referring to fig. 5, the inner pipe 10 includes a first inner pipe straight pipe 11, an inner pipe bent pipe 12 and a second inner pipe straight pipe 13 connected in sequence; the outer pipe 20 comprises a first outer pipe straight pipe 22, an outer pipe bent pipe 23 and a second outer pipe straight pipe 24 which are connected in sequence; the first outer pipe straight pipe 22 is arranged outside the first inner pipe straight pipe 11, the outer pipe bent pipe 23 is arranged outside the inner pipe bent pipe 12, and the second outer pipe straight pipe 24 is arranged outside the second inner pipe straight pipe 13. The inner tube elbow 12 and the outer tube elbow 23 are both elbows bent at an angle, such as 90 °, and the elbows are provided to facilitate installation of the double wall tube structure 100 in a corner or other location where bending is desired. In addition, the outer pipe bent pipe 23 can be installed outside the inner pipe bent pipe 12 and then bent together to form a bent pipe, that is, the outer pipe bent pipe 23 and the inner pipe bent pipe 12 are also straight pipes originally, and after the outer pipe bent pipe 23 and the inner pipe bent pipe 12 are installed together, the straight pipe is bent to form a bent pipe, so that the problem that the outer pipe bent pipe 23 cannot be sleeved outside the inner pipe bent pipe 12 due to the inner pipe bent pipe 12 and the outer pipe bent pipe 23 which are both bent pipes is solved. The present invention adopts a sectional design for both the inner tube 10 and the outer tube 20, which is convenient for transportation and placement of materials and field installation, and is not easy to operate if the tubes are too long. In addition, the sectional design also makes the return bend department buckle easily, and shorter pipe is bent and is got up more conveniently.

Preferably, the first outer pipe straight pipe 22, the outer pipe bent pipe 23 and the second outer pipe straight pipe 24 are all provided with through holes 21, so that the first outer pipe straight pipe 22, the outer pipe bent pipe 23 and the second outer pipe straight pipe 24 are respectively mounted outside the first inner pipe straight pipe 11, the inner pipe bent pipe 12 and the second inner pipe straight pipe 13 through bolts 30.

Referring to fig. 1 and 5, the ends of the first inner straight pipe 11 and the first outer straight pipe 22 are connected to a first flange 60, the ends of the second inner straight pipe 13 and the second outer straight pipe 24 are connected to a second flange 70, and the flanges are provided at the ends of the pipes to facilitate the installation of the double-wall pipe structure 100.

Referring to fig. 1, the double-walled pipe structure 100 further includes a bellows section 80, and the bellows section 80 is connected to the second flange 70. Fig. 6 is an exploded view of a bellows segment according to an embodiment of the present invention, and as shown in fig. 6, a bellows segment 80 includes a bellows 81, and a third flange 82 and a fourth flange 83 respectively disposed at two ends of the bellows 81, and the third flange 82 is connected to the second flange 70. The bellows 81 is used to connect with an inlet or a pipe of other equipment, and since the bellows 81 has elasticity, it is possible to compensate for installation errors and to reduce vibration during operation of the equipment.

Preferably, the bellows segment 80 further includes a sleeve 84, the sleeve 84 is disposed outside the bellows 81 for protecting the bellows 81, the sleeve 84 may be a rigid pipe such as a steel pipe, for example, and can protect the bellows 81, one end of the sleeve 84 is fixed to the third flange 82 or the fourth flange 83, that is, only one end of the sleeve 84 is fixed, and the other end of the sleeve 84 is not fixed, so that the bellows 81 can extend and contract, and if both ends of the sleeve 84 are fixed to the flanges, there is no freedom of movement between the third flange 82 and the fourth flange 83, so that the bellows 81 cannot extend and contract, and the bellows 81 cannot function.

Referring to fig. 1 and 5, the first outer straight pipe 22 is connected to the first flange 60 through a first half pipe 221 and a second half pipe 222, the first half pipe 221 and the second half pipe 222 can be combined into a single pipe, and the first half pipe 221 and the second half pipe 222 can be regarded as dividing a complete pipe into left and right halves. Because the inner tube 10 is welded with the first flange 60 firstly during installation, and then the outer tube 20 is welded with the first flange 60, because the inner tube 10 is welded with the first flange 60 firstly, when the outer tube 20 is welded, in order to compensate length errors, a first half tube 221 and a second half tube 222 are arranged, the first half tube 221 and the second half tube 222 are cut according to length requirements, redundant length is cut off, and then the first half tube 221 and the second half tube are welded between the outer tube 20 and the first flange 60, so that the outer tube 20 and the first flange 60 are welded, and the assembly precision is ensured. The arrangement of the two half pipes can be realized after the inner pipe 10 and the flange 60 are welded, the cut first half pipe 221 and the cut second half pipe 222 can be welded between the outer pipe 20 and the first flange 60, if the whole complete pipe is directly used to be welded between the outer pipe 20 and the first flange 60, the whole complete pipe cannot penetrate between the outer pipe 20 and the first flange 60 because the inner pipe 10 is welded with the first flange 60, so that the arrangement of the two half pipes is realized.

With continued reference to fig. 1 and 5, the second outer tube straight tube 24 is connected to the second flange 70 through a third half tube 241 and a fourth half tube 242, similar to the first half tube 221 and the second half tube 222, the third half tube 241 and the fourth half tube 242 can also be combined into a single tube, and the third half tube 241 and the fourth half tube 242 are cut as needed and then welded between the second outer tube straight tube 24 and the second flange 70 to compensate for the length error.

The first half pipe 221, the second half pipe 222, the third half pipe 241, and the fourth half pipe 242 are all about 50mm long.

Fig. 7 is a schematic structural view illustrating the assembly of the inner pipe elbow and the outer pipe elbow according to the embodiment of the present invention, and as shown in fig. 7, both ends of the inner pipe elbow 12 are longer than both ends of the outer pipe elbow 23, so that both ends of the inner pipe elbow 12 protrude from both ends of the outer pipe elbow 23, and it is convenient to weld both ends of the inner pipe elbow 12 to the first outer pipe straight pipe 22 and the second inner pipe straight pipe 13, respectively.

The present invention also discloses an assembly method for the double wall tubular structure 100 described above, comprising the steps of:

s1, sleeving the outer pipe elbow 23 outside the inner pipe elbow 12;

s2, placing the sleeve 40 on the through hole 21 on the outer pipe elbow 23;

s3, after the bolt 30 penetrates the sleeve 40 and the through hole 21 in sequence, the bolt is abutted against the inner pipe bent pipe 12, and the bolt 30 is screwed tightly;

s4, bending the inner pipe elbow 12 and the outer pipe elbow 23 together to a desired angle, for example, 90 °;

s5, welding the first inner pipe straight pipe 11 and the second inner pipe straight pipe 13 with two ends of the inner pipe bent pipe 12 respectively;

s6, sleeving the first outer pipe straight pipe 22 outside the first inner pipe straight pipe 11;

s7, placing the sleeve 40 on the through hole 21 on the first outer straight pipe 22;

s8, after the bolt 30 sequentially penetrates through the sleeve 40 and the through hole 21, the bolt is abutted against the first inner straight pipe 11, and the bolt 30 is screwed;

s9, sleeving the second outer pipe straight pipe 24 outside the second inner pipe straight pipe 13;

s10, placing the sleeve 40 on the through hole 21 on the second outer pipe straight pipe 24;

s11, after the bolt 30 sequentially penetrates through the sleeve 40 and the through hole 21, the bolt is abutted against the second inner straight pipe 13, and the bolt 30 is screwed;

s12, welding the tail end of the first inner pipe straight pipe 11 with the first flange 60;

s13, cutting the lengths of the first half pipe 221 and the second half pipe 222 according to the distance between the first outer pipe straight pipe 22 and the first flange 60, and welding the first outer pipe straight pipe 22 and the first flange 60 through the first half pipe 221 and the second half pipe 222;

s14, welding the tail end of the second inner pipe straight pipe 13 with the second flange 70;

s15, cutting the lengths of the third half pipe 241 and the fourth half pipe 242 according to the distance between the second outer pipe straight pipe 24 and the second flange 70, and welding the second outer pipe straight pipe 24 and the second flange 70 through the third half pipe 241 and the fourth half pipe 242.

The above steps are only an example, and one of the assembling manners of the double-wall pipe structure 100 of the present invention is illustrated, and the order of some of the steps can be properly adjusted by those skilled in the art according to the needs, and is not limited herein. For example, the step of bending the tube in step S4 may wait until the entire double-walled tube structure 100 is assembled and then bent.

Step S15 may be followed by the steps of assembling bellows segment 80 and attaching bellows segment 80 to second flange 70.

In addition, a step of performing flaw detection on the pipe may be added in the assembling step as needed, for example, performing 100% radiographic inspection on the inner pipe 10 and performing conventional weld inspection on the outer pipe 20. After the inner pipe 10 is qualified, an air pressure test of 1.5 times of design pressure can be performed on the inner pipe 10 to ensure that the inner pipe 10 can bear enough working pressure.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.