Butt welding structure of wound heat exchange tube

Abstract

The butt welding structure of the wound heat exchange tube comprises a tube plate (1) and a heat exchange tube (2) connected to the tube plate (1), a plurality of tube holes (1.1) are evenly formed in the tube plate (1), an annular welding flange (1.2) is arranged on the periphery of the opening end of each tube hole (1.1), a step hole (1.3) is formed in the opening end of an annular hole of each annular welding flange (1.2), and the heat exchange tube (2) is connected to the tube plate (1). And the aperture of the outer side of the stepped hole (1.3) is larger than that of the inner side. The butt welding structure of the wound tube heat exchange tube has the advantages of being fast to assemble and high in production efficiency.

Description

Technical Field

[0001] The utility model relates to a butt welding structure, in particular to a butt welding connecting structure between a heat exchange tube and a tube sheet applied to a coiled tube heat exchanger, belonging to the technical field of heat exchangers. Background Art

[0002] At present, in the manufacturing process of tubular heat exchangers (shell-and-tube heat exchangers, coiled-tube heat exchangers), the heat exchange tubes and tube sheets are generally connected in the following ways: Figure 4 In the structure shown in the figure, after the heat exchange tube is inserted into the tube hole on the tube sheet, the outer wall of the heat exchange tube is closely fitted with the inner wall of the tube hole of the tube sheet through the tube expansion mechanism, and the heat exchange tube is welded at the other end where it extends to the tube sheet, such as Figure 4 As shown. In actual applications, it is found that after adopting the above structure, the end of the heat exchange tube extending outside the other end surface of the tube sheet is not flush with the cross-section of the tube sheet due to welding, so it will affect the fluid during use and affect its flow equalization effect. For this reason, Chinese patent CN201910934621.X discloses "A method for welding heat exchange tubes and tube sheets and its application", which adopts a butt welding structure to realize the butt welding connection of the heat exchange tube at one end of the tube sheet. During the butt welding process, it is necessary to set a groove on the butt welding surface. Therefore, it requires a higher butt welding accuracy during the welding process, and needs to use professional butt welding auxiliary tooling, which makes the manufacturing efficiency low. For this reason, this patent has been improved on this basis again to reduce the butt welding accuracy and improve the manufacturing efficiency. Utility Model Content

[0003] The utility model aims to overcome the above-mentioned shortcomings and provide a butt welding structure of a coiled tube heat exchange tube with high production efficiency.

[0004] The purpose of the utility model is achieved in this way:

[0005] A butt welding structure for heat exchange tubes comprises a tube sheet and a heat exchange tube connected to the tube sheet, wherein a plurality of tube holes are evenly arranged on the tube sheet, an annular welding flange is arranged around the opening end of each tube hole, the opening end of the annular hole of the annular welding flange is arranged as a step hole, and the outer hole diameter of the step hole is larger than the inner hole diameter.

[0006] Preferably, the annular hole of the annular welding flange is connected to the tube hole and has the same hole diameter, that is, the hole diameter of the inner small-diameter end of the step hole is equal to the hole diameter of the tube hole.

[0007] Preferably, the bottom of the outer wall of the annular welding flange is connected to the end surface of the tube sheet by a circular arc transition.

[0008] Preferably, the tube sheet and the annular welding flange are an integral structure formed in one piece.

[0009] Preferably, the depth of the large-diameter end of the step hole is 0.7-1.0 mm.

[0010] Compared with the prior art, the beneficial effects of the utility model are:

[0011] The utility model provides a step hole on the annular welding flange of the tube sheet of the wound tube heat exchanger, so as to facilitate the rapid insertion and positioning of the heat exchange tube during the welding process, thereby greatly improving the production efficiency. Then welding is performed, and because the wall of the step hole is thinner, it will be fused with the heat exchange tube during the welding process, making the connection more firm. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The utility model is a schematic diagram of a butt welding structure of a coiled tube heat exchange tube.

[0013] Figure 2 It is a structural schematic diagram of the tube plate of the utility model.

[0014] Figure 3 It is a partial schematic diagram of the pipe hole of the utility model.

[0015] Figure 4 Schematic diagram of the welding structure of conventional tube sheets and heat exchange tubes.

[0016] in:

[0017] Tube sheet 1, heat exchange tube 2, center tube 3;

[0018] Tube hole 1.1;

[0019] Annular welding flange 1.2, step hole 1.3. DETAILED DESCRIPTION

[0020] See also Figures 1 to 3 The utility model relates to a butt welding structure of a tube-wound heat exchange tube, comprising a tube sheet 1 and a heat exchange tube 2 connected to the tube sheet 1, wherein a central tube 3 is connected to the tube sheet 1, and the heat exchange tube 2 is wound around the central tube 3 in multiple layers.

[0021] Specifically, a plurality of tube holes 1.1 are evenly arranged on the tube sheet 1. On the same end face of the tube sheet 1, an annular welding flange 1.2 is arranged around the opening end of each tube hole 1.1, and the bottom of the outer wall of the annular welding flange 1.2 is connected to the cross section of the tube sheet 1 by an arc transition, and the tube sheet 1 and the annular welding flange 1.2 are an integrated structure, which is manufactured by an integrated molding method.

[0022] The annular hole of the annular welding flange 1.2 is connected to the tube hole 1.1 and has the same aperture, and the open end of the annular hole of the annular welding flange 1.2 is set as a step hole 1.3. During butt welding, the heat exchange tube 2 is inserted into the step hole 1.3 of the annular welding flange 1.2 (the aperture of the large-diameter end of the step hole 1.3 is slightly larger than the outer diameter of the heat exchange tube 2, such as the aperture of the large-diameter end of the step hole 1.3 in this embodiment is 0.1mm larger than the outer diameter of the heat exchange tube 2, so as to facilitate the insertion of the heat exchange tube 2, and the slightly larger gap also makes the fusion between the two tighter during subsequent welding), and the end face of the heat exchange tube 2 is abutted against the step surface of the step hole 1.3, and then welded together; due to the presence of the step hole 1.3, the entire butt welding process is faster and more convenient, thereby greatly improving the production efficiency. Preferably, the depth of the large-diameter end of the step hole 1.3 is 0.7-1.0 mm, which not only facilitates the docking of the heat exchange tube 2 and the tube hole 1.1, but also makes it easier to melt through during welding, so that the heat exchange tube 2 and the annular welding flange 1.2 are welded together.

[0023] In addition: It should be noted that the above specific implementation is only an optimization scheme of this patent. Any changes or improvements made by technicians in this field based on the above concept are within the scope of protection of this patent.

Claims

1. A butt-welded structure of a coiled heat exchange tube, comprising a tube sheet (1) and a heat exchange tube (2) connected to the tube sheet (1), characterized in that: The tube plate (1) is evenly provided with a plurality of tube holes (1.1), an annular welding flange (1.2) is provided around the opening end of each tube hole (1.1), the opening end of the annular hole of the annular welding flange (1.2) is provided as a step hole (1.3), and the outer hole diameter of the step hole (1.3) is larger than the inner hole diameter.

2. The butt welding structure of a coiled tube heat exchanger according to claim 1, characterized in that: The annular hole of the annular welding flange (1.2) is connected to the tube hole (1.1) and has the same hole diameter, that is, the hole diameter of the inner small hole diameter end of the step hole (1.3) is equal to the hole diameter of the tube hole (1.1).

3. The butt welding structure of a coiled tube heat exchanger according to claim 1, characterized in that: The bottom of the outer wall of the annular welding flange (1.2) and the end surface of the tube sheet (1) are connected in a circular arc transition.

4. The butt welding structure of the coiled tube heat exchanger according to claim 3, characterized in that: The tube sheet (1) and the annular welding flange (1.2) are an integral structure formed in one piece.

5. The butt welding structure of a coiled tube heat exchanger according to claim 1, characterized in that: The depth of the large-diameter end of the step hole (1.3) is 0.7-1.0 mm.

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