Compression device, heat exchange system and tube assembly

Abstract

This application discloses a compression device, a heat exchange system, and a pipe assembly. The compression device includes a compressor, a liquid receiver, and a pipe assembly. The compressor includes a housing and a compression mechanism. The housing has a port, and the compression mechanism is located inside the housing and has a suction port. The liquid receiver is located outside the housing and has a liquid outlet. The pipe assembly includes an installation pipe, a first pipe body, and a second pipe body. The installation pipe is connected to the port. The first pipe body is inserted into the installation pipe, with one end connected to the suction port and the other end connected to the installation pipe. One end of the second pipe body is connected to the other end of the first pipe body, and the other end of the second pipe body is connected to the liquid outlet. The installation pipe and the first pipe body are steel pipes. At least a portion of the second pipe body is located outside the first pipe body and the installation pipe, and the second pipe body is a stainless steel pipe.

Description

Technical Field

[0001] This invention relates to the field of compression device technology, and in particular to a compression device, heat exchange system, and tube assembly. Background Technology

[0002] In related technologies, a compression device includes a compressor and a receiver. The compressor is a device used for heat transfer in a heat exchange system. The compression mechanism in the compressor is connected to the receiver via a connecting pipe, thereby completing the air intake from the receiver to the compression mechanism. However, the connecting pipes in existing compression devices have high material costs and short service lives, which affects the production cost and service life of the compression device. Summary of the Invention

[0003] The main objective of this invention is to provide a compression device, a heat exchange system, and a tube assembly, which aims to reduce the production cost of the compression device while increasing its service life.

[0004] To achieve the above objectives, this application proposes a compression device, comprising: A compressor includes a housing and a compression mechanism, the housing having an inlet, and the compression mechanism being disposed within the housing and having an intake port; A liquid reservoir is disposed outside the housing and has a liquid outlet; The tube assembly includes an installation tube, a first tube body, and a second tube body. The installation tube is connected to the port. The first tube body is inserted into the installation tube, with one end connected to the air intake and the other end connected to the installation tube. One end of the second tube body is connected to the other end of the first tube body, and the other end of the second tube body is connected to the liquid storage outlet. The installation tube and the first tube body are steel pipes. At least a portion of the second tube body is located outside the first tube body and the installation tube, and the second tube body is a stainless steel pipe.

[0005] In some embodiments, the other end of the second tube is inserted into the liquid storage outlet, and the second tube is connected to the liquid storage container by high-frequency induction brazing or flame brazing. A first sealing brazing seam is formed between the outer peripheral wall of the second tube and the liquid storage container.

[0006] In some embodiments, the second tube body and the reservoir are welded together by brass flux-cored solder to form the first sealing seam, and the first sealing seam is arranged in a ring around the outer peripheral wall of the second tube body.

[0007] In some embodiments, one end of the second tube is inserted into the first tube, and the second tube and the first tube are connected by high-frequency induction brazing or flame brazing. A second sealing brazing seam is formed between the outer peripheral wall of the second tube and the end of the first tube.

[0008] In some embodiments, the second tube body and the first tube body are welded together by brass flux-cored brazing filler metal to form the second sealing seam, and the second sealing seam is arranged in a ring around the outer peripheral wall of the second tube body.

[0009] In some embodiments, the other end of the first tube extends out of the mounting tube, and the first tube and the mounting tube are connected by high-frequency induction brazing or flame brazing, and a third sealing brazing seam is formed between the outer peripheral wall of the first tube and the end of the mounting tube.

[0010] In some embodiments, the first tube body and the mounting tube are welded together by brass flux-cored brazing filler metal to form the third sealing seam, which is arranged in a ring around the outer peripheral wall of the first tube body.

[0011] In some embodiments, the end of the mounting tube near the housing is bent outward to form a flange, the flange abutting against the inner side of the tube opening, the mounting tube and the housing are connected by high-frequency induction brazing or flame brazing, and a fourth sealing brazing seam is formed between the outer peripheral wall of the mounting tube and the housing.

[0012] In some embodiments, the mounting tube and the housing are welded together by brass flux-cored brazing filler metal to form the fourth sealing seam, which is arranged in a ring around the outer peripheral wall of the mounting tube.

[0013] In some embodiments, the second tube is welded to the reservoir and the first tube respectively using brass flux-cored solder, and the mounting tube is welded to the first tube and the housing respectively using brass flux-cored solder. The brass flux-cored solder includes a brass sheath and a flux core filled in the brass sheath. The brass sheath has a soldering opening with a width not greater than 0.5 mm.

[0014] In some embodiments, the second tube is a stainless steel tube with a carbon content of no more than 0.03%; And / or, the hardness of the second tube is 100-210 Hv.

[0015] In some embodiments, the second tube is a 304L stainless steel tube.

[0016] In some embodiments, the first tube includes a first connecting segment and a second connecting segment connected together. The inner diameter of the first connecting segment is smaller than the inner diameter of the second connecting segment. The first connecting segment is inserted into the air intake hole and is interference-fitted with the air intake hole. Sealing oil is provided between the first connecting segment and the hole wall of the air intake hole. One end of the second tube is inserted into the second connecting segment and is welded to the second connecting segment by high-frequency induction brazing or flame brazing.

[0017] In some embodiments, the first pipe body further includes a transition section, the transition section connecting the first connecting section and the second connecting section, wherein the inner diameter and outer diameter of the transition section are both gradually widened along the direction from the first connecting section to the second connecting section; And / or, the first connecting segment and the second connecting segment are arranged in a cylindrical shape.

[0018] In some embodiments, the second pipe body includes a first pipe segment, a bend segment, and a second pipe segment connected in sequence. The first pipe segment is connected to the first pipe body, and the second pipe segment is connected to the liquid storage outlet. The extension directions of the first pipe segment and the second pipe segment intersect. The minimum outer diameter of the first pipe segment and the second pipe segment is D. Along the extension direction of the first pipe segment, the minimum distance between the end of the first pipe segment away from the bend segment and the central axis of the second pipe segment is L1. Along the extension direction of the second pipe segment, the minimum distance between the end of the second pipe segment away from the bend segment and the central axis of the first pipe segment is L2. D, L1, and L2 satisfy: L1 ≥ 1.5D, L2 ≥ 1.5D.

[0019] In some embodiments, the first pipe segment and the second pipe segment are arranged in a straight pipe shape, and the wall thickness of the first pipe segment and the second pipe segment is not less than 0.8 mm; And / or, the wall thickness of the bend is not less than 0.4 mm.

[0020] This application also proposes a heat exchange system, which includes the compression device described above.

[0021] This application also proposes a pipe assembly for connecting the compression mechanism of a compressor and a liquid receiver. The pipe assembly includes an installation pipe, a first pipe body, and a second pipe body. The installation pipe is used to connect to a port on the compressor housing. The first pipe body is inserted into the installation pipe, with one end connected to the suction port of the compression mechanism and the other end connected to the installation pipe. One end of the second pipe body is connected to the other end of the first pipe body, and the other end is used to connect to the liquid receiver outlet of the liquid receiver. The installation pipe and the first pipe body are steel pipes. At least a portion of the second pipe body is located outside the first pipe body and the installation pipe, and the second pipe body is made of stainless steel.

[0022] In the technical solution of this application, the compression device includes a compressor, a liquid reservoir, and a pipe assembly. The pipe assembly includes an installation pipe, a first pipe body, and a second pipe body. The installation pipe is connected to the port of the housing. The first pipe body is inserted into the installation pipe, with one end connected to the suction port of the compression mechanism and the other end connected to the installation pipe. One end of the second pipe body is connected to the other end of the first pipe body, and the other end of the second pipe body is connected to the liquid reservoir outlet. By inserting and connecting the installation pipe and the first pipe body, the sealing performance and connection strength between the pipe bodies are improved. The installation pipe and the first pipe body are made of steel pipes, which, compared to copper pipes, are advantageous in reducing... The lower material cost also improves the structural stability of the tube assembly and its resistance to deformation at the pipe ends, enabling the tube assembly to better withstand the vibration of the heat exchange system and the stress in the pipeline, thereby improving the sealing reliability and fatigue life of the tube assembly connections. At least a portion of the second tube is located outside the first tube and the mounting pipe. The second tube is made of stainless steel, which, compared to copper tubes, helps reduce material costs and allows the second tube exposed outside the shell to effectively resist the erosion of corrosive media, improving the corrosion resistance and rust resistance of the exposed portion of the tube assembly, thus extending the service life of the tube assembly. Therefore, the technical solution of this application helps reduce the material cost of the tube assembly and increase its service life, thereby reducing the production cost of the compression device while increasing its service life. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 A schematic diagram of the structure of an embodiment of the compression device provided in this application; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 A schematic diagram of another embodiment of the compression device provided in this application; Figure 4 for Figure 3 Enlarged view of point B in the middle; Figure 5 This is a cross-sectional view of an embodiment of the first tube body of this application; Figure 6 This is a cross-sectional view of an embodiment of the second tube body of this application; Figure 7 This is a cross-sectional view of an embodiment of the second tube body of this application; Figure 8 This is a schematic diagram showing the tube assembly of this application connected by brass flux-cored solder. Figure 9 This is a schematic diagram of the brass flux-cored solder of this application.

[0025] Explanation of icon numbers: 10. Compression device; 100. Compressor; 110. Housing; 111. Pipe port; 120. Compression mechanism; 121. Suction port; 200. Liquid reservoir; 210. Liquid reservoir outlet; 300. Pipe body assembly; 310. Installation pipe; 311. Flanged edge; 320. First pipe body; 321. First connecting section; 322. Second connecting section; 323. Transition section; 330. Second pipe body; 331. First pipe segment; 332. Bend segment; 333. Second pipe segment; 400, Brass flux-cored brazing filler metal; 410, Brass sheath; 420, Flux core; 430, Soldering opening; 440, Brass wire; 401, First sealing brazing seam; 402, Second sealing brazing seam; 403, Third sealing brazing seam; 404, Fourth sealing brazing seam.

[0026] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0029] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0030] In related technologies, a compression device includes a compressor and a receiver. The compressor is a device used for heat transfer in a heat exchange system. The compression mechanism in the compressor is connected to the receiver via a connecting pipe, thereby completing the air intake from the receiver to the compression mechanism. However, the connecting pipes in existing compression devices have high material costs and short service lives, which affects the production cost and service life of the compression device.

[0031] Based on this, this application proposes a compression device that reduces the material cost of the tube assembly and increases the service life of the tube assembly, thereby reducing the production cost of the compression device while increasing its service life.

[0032] Please see Figures 1 to 9 In one embodiment of this application, the compression device 10 includes a compressor 100, a liquid reservoir 200, and a pipe assembly 300. The compressor 100 includes a housing 110 and a compression mechanism 120. The housing 110 has a pipe opening 111, and the compression mechanism 120 is disposed inside the housing 110 and has an air intake 121. The liquid reservoir 200 is disposed outside the housing 110 and has a liquid outlet 210. The pipe assembly 300 includes an installation pipe 310, a first pipe body 320, and a second pipe body 330. The installation pipe 310 is connected to... The pipe opening 111 is connected; the first pipe body 320 is inserted into the installation pipe 310, one end of the first pipe body 320 is connected to the air intake 121 and the other end is connected to the installation pipe 310; one end of the second pipe body 330 is connected to the other end of the first pipe body 320, and the other end of the second pipe body 330 is connected to the liquid storage outlet 210; the installation pipe 310 and the first pipe body 320 are steel pipes; at least part of the second pipe body 330 is located outside the first pipe body 320 and the installation pipe 310, and the second pipe body 330 is a stainless steel pipe.

[0033] The housing 110 is provided with a pipe port 111 for connecting to a pipeline, serving as a channel interface for refrigerant inflow and outflow. The specific location of the pipe port 111 is not limited; exemplarily, the pipe port 111 is located on the outer peripheral wall of the housing 110 and near the bottom of the housing 110, corresponding to the position of the suction port 121 of the compression mechanism 120. The compression mechanism 120 is a component that compresses gas. The compression mechanism 120 can be a cylinder and a piston installed in the cylinder. A motor for driving the compression mechanism 120 is also installed inside the housing 110. The motor drives the compression mechanism 120 to compress the refrigerant drawn in from the liquid receiver 200.

[0034] The liquid receiver 200 is a container component used to store and / or separate a gas-liquid two-phase working medium. The compression mechanism 120 and the liquid receiver 200 are interconnected through a pipe assembly 300. The pipe assembly 300 includes an installation pipe 310, a first pipe 320, and a second pipe 330. The gaseous refrigerant in the liquid receiver 200 flows out from the liquid outlet 210 and flows sequentially through the second pipe 330, the first pipe 320, and the installation pipe 310 before flowing into the compression mechanism 120 through the suction port 121.

[0035] For example, one end of the installation tube 310 is sealed to the port 111 of the housing 110, the first tube 320 is inserted into the installation tube 310, one end of the first tube 320 is sealed to the inner wall of the suction hole 121, and the other end of the first tube 320 is sealed to the installation tube 310; one end of the second tube 330 is inserted into the first tube 320 and sealed to the first tube 320, and the other end of the second tube 330 is sealed to the liquid storage outlet 210. The first tube 320 and the inner wall of the suction port 121 can be sealed together by means of sealing, interference fit, welding, etc.; the first tube 320 and the mounting tube 310 can be sealed together by welding; the first tube 320 and the second tube 330 can be sealed together by welding; the second tube 330 and the liquid reservoir 200 can be sealed together by welding. This arrangement can prevent external gas from leaking into the tube assembly 300 or the gaseous refrigerant in the tube assembly 300 from leaking into the outside.

[0036] The mounting pipe 310 is made of steel, which ensures the structural strength of the connection between the mounting pipe 310 and the pipe opening 111 of the housing 110 and resists deformation; and compared with copper pipe, it can reduce material costs, thereby reducing the production cost of the compression device 10.

[0037] The first tube body 320 is a steel pipe. One end of the first tube body 320 is connected to the suction port 121, giving it structural strength that maintains an interference fit with the inner wall of the suction port 121, thus facilitating the connection and fixation between the first tube body 320 and the suction port 121. The other end of the first tube body 320 is connected to the mounting pipe 310. Both the mounting pipe 310 and the first tube body 320 are steel pipes, allowing the connection to withstand greater vibration and pipeline stress in the heat exchange system, thereby ensuring the sealing reliability of the connection. Furthermore, the fact that both the mounting pipe 310 and the first tube body 320 are steel pipes allows them to be welded together using high-frequency induction brazing or flame brazing without the need for manual brazing, further reducing welding costs. For example, the steel pipe can be an alloy steel pipe or a stainless steel pipe; no specific limitation is made here.

[0038] At least a portion of the second tube 330 is disposed outside the first tube 320 and the mounting tube 310, that is, the second tube 330 extends outside the first tube 320 and the mounting tube 310 to facilitate connection with the reservoir 200 outside the housing 110; and the second tube 330 is a stainless steel tube, which allows the second tube 330 to be isolated from external moisture and corrosive media. Stainless steel tubes have corrosion resistance and rust resistance, which helps to improve the service life of the exposed second tube 330. Furthermore, the second tube 330 is made of stainless steel, which allows the second tube 330 to be welded to the first tube 320 and the reservoir 200 by high-frequency induction brazing or flame brazing without the need for manual brazing, further reducing welding costs. For example, the stainless steel tube can be 304L stainless steel or 316L stainless steel, and the specific type is not limited here.

[0039] The compression device 10 of this application uses a highly economical steel pipe to support and fix the first pipe body 320 inside the compression device 10, and a corrosion-resistant stainless steel pipe to protect the second pipe body 330 outside the compression device 10. This helps to reduce material costs while improving the overall strength, sealing reliability and corrosion resistance life of the pipe body assembly 300.

[0040] In the technical solution of this application, the compression device 10 includes a compressor 100, a liquid reservoir 200, and a pipe assembly 300. The pipe assembly 300 includes an installation pipe 310, a first pipe 320, and a second pipe 330. The installation pipe 310 is connected to the port 111 of the housing 110. The first pipe 320 is inserted into the installation pipe 310. One end of the first pipe 320 is connected to the suction port 121 of the compression mechanism 120, and the other end is connected to the installation pipe 310. One end of the second pipe 330 is connected to the other end of the first pipe 320, and the other end of the second pipe 330 is connected to the liquid reservoir outlet 210 of the liquid reservoir 200. By inserting and connecting the installation pipe 310 and the first pipe 320, the sealing performance and connection strength between the pipes are improved. The 320 is made of steel pipe, which, compared to copper pipe, helps reduce material costs and improves the structural stability of the pipe assembly 300 and its resistance to deformation at the pipe opening 111. This allows the pipe assembly 300 to better withstand the vibration of the heat exchange system and the stress in the pipeline, thereby improving the sealing reliability and fatigue life of the pipe assembly 300's connections. At least a portion of the second pipe 330 is located outside the first pipe 320 and the mounting pipe 310. The second pipe 330 is made of stainless steel, which, compared to copper pipe, helps reduce material costs and allows the second pipe 330 exposed outside the shell 110 to effectively resist the erosion of corrosive media. This improves the corrosion resistance and rust resistance of the portion of the pipe assembly 300 exposed outside the shell 110, thus extending the service life of the pipe assembly 300. Therefore, the technical solution of this application helps reduce the material cost of the pipe assembly 300 and extend its service life, thereby reducing the production cost of the compression device 10 while extending its service life.

[0041] In one embodiment, the other end of the second tube 330 is inserted into the liquid storage outlet 210. The second tube 330 and the liquid storage container 200 are connected by high-frequency induction brazing or flame brazing. A first sealing brazing seam 401 is formed between the outer peripheral wall of the second tube 330 and the liquid storage container 200.

[0042] Understandably, the other end of the second tube 330 is inserted into the liquid storage outlet 210 to facilitate precise positioning of one end of the second tube 330, ensure coaxiality of the connection, and allow the brazing filler metal to fill the gap between the inner wall of the second tube 330 and the liquid storage outlet 210, thereby improving the welding quality.

[0043] High-frequency induction brazing utilizes high-frequency alternating current to generate induced eddy currents on the second tube 330 and the reservoir 200, thereby achieving localized rapid heating. After the brazing filler metal melts, a first sealing brazing seam 401 is formed. High-frequency induction brazing has the characteristics of concentrated heating, fast speed, small heat-affected zone, and high degree of automation.

[0044] Flame brazing uses the flame of a combustible gas combustion to heat and melt the brazing filler metal to form a bond. Flame brazing equipment is simple and suitable for welding in various complex positions.

[0045] For example, the liquid outlet 210 of the liquid reservoir 200 is made of steel, specifically cold-rolled steel sheet (SPCC).

[0046] The second tube 330 and the liquid reservoir 200 are connected by high-frequency induction brazing or flame brazing, so that the two are firmly connected together and can withstand the vibration and pressure pulsation of the heat exchange system, which is beneficial to improving the welding sealing reliability of the stainless steel tube and the cold-rolled steel plate. A first sealing brazing seam 401 is formed between the outer peripheral wall of the second tube 330 and the liquid reservoir 200. The first sealing brazing seam 401 can prevent refrigerant leakage and improve the sealing performance.

[0047] In one embodiment, the second tube 330 and the reservoir 200 are welded together by brass flux-cored brazing filler metal 400 to form a first sealing weld seam 401, which is arranged in a ring around the outer peripheral wall of the second tube 330.

[0048] Understandably, the brass flux-cored solder 400 is a welding material with a brass base and an internal flux core 420. The flux core 420 serves as a flux. The brass flux-cored solder 400 has good wettability, flowability, and strength, making it suitable for connecting stainless steel tubes to the steel of the reservoir 200 to form a strong first sealing weld seam 401. The annular first sealing weld seam 401 ensures a sealed structure at the connection between the second tube 330 and the reservoir 200, preventing refrigerant leakage and improving the reliability of the compression device 10.

[0049] In one embodiment, one end of the second tube 330 is inserted into the first tube 320, and the second tube 330 and the first tube 320 are connected by high-frequency induction brazing or flame brazing. A second sealing brazing seam 402 is formed between the outer peripheral wall of the second tube 330 and the end of the first tube 320.

[0050] Understandably, one end of the second tube 330 is inserted into the first tube 320 to facilitate precise positioning of one end of the second tube 330, ensure coaxiality of the connection, and allow the brazing filler metal to fill the gap between the inner walls of the second tube 330 and the first tube 320, thereby improving the welding quality.

[0051] High-frequency induction brazing utilizes high-frequency alternating current to generate induced eddy currents on the second tube body 330 and the first tube body 320, thereby achieving localized rapid heating. After the brazing filler metal melts, a second sealing brazing seam 402 is formed. High-frequency induction brazing has the characteristics of concentrated heating, fast speed, small heat-affected zone, and high degree of automation.

[0052] Flame brazing uses the flame of a combustible gas combustion to heat and melt the brazing filler metal to form a bond. Flame brazing equipment is simple and suitable for welding in various complex positions.

[0053] The second tube 330 and the first tube 320 of this design are connected by high-frequency induction brazing or flame brazing, so that the two are firmly connected together and can withstand the vibration and pressure pulsation of the heat exchange system, which is beneficial to improving the welding sealing reliability of stainless steel tubes and steel tubes; a second sealing brazing seam 402 is formed between the outer peripheral wall of the second tube 330 and the end of the first tube 320, which can prevent refrigerant leakage and improve the sealing performance.

[0054] In one embodiment, the second tube 330 and the first tube 320 are welded together by brass flux-cored brazing filler metal 400 to form a second sealing weld seam 402, which is arranged in a ring around the outer peripheral wall of the second tube 330.

[0055] Understandably, the brass flux-cored brazing filler metal 400 is a welding material with a brass base and an internal flux core 420. The flux core 420 serves as a flux. The brass flux-cored brazing filler metal 400 has good wettability, flowability, and strength, making it suitable for connecting stainless steel pipes to steel pipes to form a strong second sealing weld seam 402. The annular second sealing weld seam 402 ensures a sealed structure at the connection between the second pipe body 330 and the first pipe body 320, preventing refrigerant leakage and improving the reliability of the compression device 10.

[0056] In one embodiment, the other end of the first tube 320 extends out of the mounting tube 310. The first tube 320 and the mounting tube 310 are connected by high-frequency induction brazing or flame brazing. A third sealing brazing seam 403 is formed between the outer peripheral wall of the first tube 320 and the end of the mounting tube 310.

[0057] Understandably, the other end of the first tube 320 extends out of the mounting tube 310 to facilitate brazing and brazing to form a third sealing brazed joint 403, and to allow the brazing filler metal to fill the gap between the inner wall of the first tube 320 and the mounting tube 310, thereby improving the welding quality.

[0058] High-frequency induction brazing utilizes high-frequency alternating current to generate induced eddy currents on the first tube 320 and the mounting tube 310 to achieve localized rapid heating. After the brazing filler metal melts, a third sealing brazing seam 403 is formed. High-frequency induction brazing has the characteristics of concentrated heating, fast speed, small heat-affected zone, and high degree of automation.

[0059] Flame brazing uses the flame of a combustible gas combustion to heat and melt the brazing filler metal to form a bond. Flame brazing equipment is simple and suitable for welding in various complex positions.

[0060] In this design, the first tube body 320 and the mounting tube 310 are connected by high-frequency induction brazing or flame brazing, so that the two are firmly connected together and can withstand the vibration and pressure pulsation of the heat exchange system, which is beneficial to improving the welding sealing reliability of stainless steel tubes and steel tubes; a third sealing brazing seam 403 is formed between the outer peripheral wall of the first tube body 320 and the end of the mounting tube 310. The third sealing brazing seam 403 can prevent the lubricating oil in the shell 110 from leaking and improve the sealing performance.

[0061] In one embodiment, the first tube body 320 and the mounting tube 310 are welded together by brass flux-cored brazing filler metal 400 to form a third sealing weld seam 403, which is arranged in a ring around the outer peripheral wall of the first tube body 320.

[0062] Understandably, the brass flux-cored brazing filler metal 400 is a welding material with a brass base and an internal flux core 420. The flux core 420 serves as a flux. The brass flux-cored brazing filler metal 400 has good wettability, flowability, and strength, making it suitable for connecting stainless steel pipes to steel pipes to form a strong third sealing weld seam 403. The annular third sealing weld seam 403 ensures a sealed structure at the connection between the first pipe body 320 and the mounting pipe 310, preventing lubricating oil leakage from the housing 110 and improving the reliability of the compression device 10.

[0063] Please see Figure 2 In one embodiment, the end of the mounting tube 310 near the housing 110 is bent outward to form a flange 311, the flange 311 abuts against the inner side of the tube opening 111, the mounting tube 310 and the housing 110 are connected by high frequency induction brazing or flame brazing, and a fourth sealing brazing seam 404 is formed between the outer peripheral wall of the mounting tube 310 and the housing 110.

[0064] It is understandable that when the flange 311 abuts against the inner edge of the tube opening 111, the installation of the mounting tube 310 is more stable, which facilitates the welding connection between the mounting tube 310 and the housing 110, improves the welding stability, and allows the brazing filler to fill the gap between the mounting tube 310 and the edge of the tube opening 111 of the housing 110, thereby improving the welding quality.

[0065] High-frequency induction brazing utilizes high-frequency alternating current to generate induced eddy currents on the mounting tube 310 and the shell 110 to achieve localized rapid heating. After the brazing filler metal melts, a fourth sealing brazing seam 404 is formed. High-frequency induction brazing has the characteristics of concentrated heating, fast speed, small heat-affected zone, and high degree of automation.

[0066] Flame brazing uses the flame of a combustible gas combustion to heat and melt the brazing filler metal to form a bond. Flame brazing equipment is simple and suitable for welding in various complex positions.

[0067] For example, the material of the port 111 of the housing 110 is steel, specifically cold-rolled steel sheet (SPCC).

[0068] In this design, the mounting pipe 310 and the shell 110 are connected by high-frequency induction brazing or flame brazing, so that the two are firmly connected together and can withstand the vibration and pressure pulsation of the heat exchange system, which is beneficial to improving the welding sealing reliability of the stainless steel pipe and the cold-rolled steel plate. A fourth sealing brazing seam 404 is formed between the outer peripheral wall of the mounting pipe 310 and the shell 110. The fourth sealing brazing seam 404 can prevent the lubricating oil in the shell 110 from leaking and improve the sealing performance.

[0069] In one embodiment, the mounting tube 310 and the housing 110 are welded together by brass flux-cored brazing filler metal 400 to form a fourth sealing weld seam 404, which is arranged in a ring around the outer peripheral wall of the mounting tube 310.

[0070] Understandably, the brass flux-cored solder 400 is a welding material with a brass base and an internal flux core 420. The flux core 420 serves as a flux. The brass flux-cored solder 400 has good wettability, flowability, and strength, making it suitable for connecting stainless steel tubes to the steel of the housing 110 to form a strong fourth sealing weld seam 404. The annular fourth sealing weld seam 404 ensures a sealed structure at the connection between the mounting tube 310 and the housing 110, preventing lubricating oil leakage from the housing 110 and improving the reliability of the compression device 10.

[0071] Please see Figure 8 and Figure 9 In one embodiment, the second tube 330 is welded to the reservoir 200 and the first tube 320 respectively by brass flux-cored solder 400, and the mounting tube 310 is welded to the first tube 320 and the shell 110 respectively by brass flux-cored solder 400. The brass flux-cored solder 400 includes a brass outer sheath 410 and a flux core 420 filled in the brass outer sheath 410. The brass outer sheath 410 is provided with a soldering opening 430, and the width of the soldering opening 430 is not greater than 0.5mm.

[0072] It is understandable that the pipe components 300 in this solution are all connected by brass flux-cored brazing filler metal 400, which is conducive to unifying and simplifying the welding process. Brass flux-cored brazing filler metal 400 is suitable for connecting dissimilar materials between stainless steel pipes and steel pipes or other metals. Brass flux-cored brazing filler metal 400 has good wettability and flux-cored 420 welding assistance, which can ensure the welding quality and sealing reliability of the connection point.

[0073] The brass outer sheath 410 is a pre-formed welding wire with a flux opening 430. The wire is filled with flux core 420. During welding heating, the brass outer sheath 410 melts as filler metal, while the flux core 420 flows out due to heat. This removes the oxide film, promotes solder flow, and protects the welding area. The flux opening 430 ensures the flux core 420 flows out, thus improving the convenience of the welding process and the stability of the weld quality. For example, the width of the flux opening 430 is 0.2mm, 0.3mm, 0.4mm, or 0.5mm, but it can also be any other value within the above range.

[0074] For example, the brass outer sheath 410 is a copper-zinc alloy welding wire. For example, the flux core 420 is a flux, which is composed of boric acid, borax, and fluoride, with an activation temperature of 750-1050℃. The boric acid accounts for 70-90% of the total weight of the flux core 420, the borax accounts for 5-20% of the total weight of the flux core 420, the fluoride accounts for 3-10% of the total weight of the flux core 420, and the flux core 420 accounts for 10-25% of the total weight of the brass flux-cored solder 400.

[0075] In one embodiment, the brass flux-cored filler metal 400 further includes a brass wire 440 disposed within the brass sheath 410. With this arrangement, during welding heating, the internal brass wire 440 and the external brass sheath 410 melt together. The brass wire 440, as a high-melting-point metal pre-uniformly arranged within the flux core 420, guides and stabilizes the flow of the molten filler metal during its melting process. This facilitates a more uniform and stable formation of a sealed weld seam by the brass flux-cored filler metal 400, reducing welding defects such as porosity or discontinuous filling, and improving welding reliability.

[0076] In one embodiment, the second tube 330 is a stainless steel tube with a carbon content of no more than 0.03%. This configuration means the second tube 330 is an ultra-low carbon stainless steel tube. By limiting the carbon content of the second tube 330 to no more than 0.03%, this design reduces the precipitation of chromium carbide, thereby ensuring that the weld seam between the second tube 330 and the first tube 320 and the reservoir 200 has good corrosion resistance. This improves the corrosion resistance and sealing performance of the welded joint, meeting the requirement that the second tube 330 is exposed outside the housing 110. For example, the second tube 330 is made of 304L stainless steel, 316L stainless steel, etc.

[0077] In one embodiment, the hardness of the second tube 330 is 100–210 Hv. This means that the Vickers hardness of the second tube 330 after quenching is within the range of 100 to 210 Hv. A hardness of not less than 100 Hv ensures that the second tube 330 has sufficient strength and rigidity, preventing deformation and damage due to excessive softness. A hardness of not more than 210 Hv ensures that the second tube 330 has good plasticity and toughness, facilitating welding and reducing the risk of brittle fracture. This improves the manufacturing feasibility and structural reliability of the second tube 330. For example, the hardness value of the second tube 330 can be 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, or 210 Hv, or any other value within the aforementioned range.

[0078] In one embodiment, the second tube 330 is a 304L stainless steel tube. This configuration results in an extremely low carbon content in the second tube 330. The extremely low carbon content reduces the risk of chromium carbide precipitation during brazing, thereby ensuring that the sealed brazing joint after the second tube 330 is welded to the first tube 320 and the reservoir 200 has good corrosion resistance. This improves the corrosion resistance and sealing performance of the welded joint, meeting the requirement that the second tube 330 is exposed outside the housing 110.

[0079] Please see Figure 5 In one embodiment, the first tube 320 includes a first connecting section 321 and a second connecting section 322 connected together. The inner diameter of the first connecting section 321 is smaller than the inner diameter of the second connecting section 322. The first connecting section 321 is inserted into the air intake hole 121 and is press-fitted with the air intake hole 121. Sealing oil is provided between the first connecting section 321 and the hole wall of the air intake hole 121. One end of the second tube 330 is inserted into the second connecting section 322 and is welded to the second connecting section 322 by high-frequency induction brazing or flame brazing.

[0080] Both the first connecting section 321 and the second connecting section 322 can be circular tube structures. The inner diameter of the first connecting section 321 is smaller than that of the second connecting section 322. The smaller inner diameter of the first connecting section 321 facilitates an interference fit with the suction hole 121. The larger inner diameter of the second connecting section 322 provides a larger contact area for the insertion and welding of the second tube body 330, improving welding convenience and connection strength.

[0081] For example, the first connecting section 321 and the second connecting section 322 are coaxially connected, so that when the refrigerant flows from the reservoir 200 to the suction port 121, the refrigerant does not need to go through a special bend, which can reduce the flow resistance and fluid turbulence of the refrigerant.

[0082] The contact surface of the first connecting section 321 and the wall of the suction port 121 is provided with sealing oil to form an oil film between them, which effectively prevents refrigerant leakage and improves the reliability of the compression device 10.

[0083] One end of the second tube body 330 is connected to the second connecting section 322 by high-frequency induction brazing or flame brazing, so that the two are firmly connected together and can withstand the vibration and pressure pulsation of the heat exchange system, which is beneficial to improving the welding sealing reliability of stainless steel tubes and steel tubes; a second sealing brazing seam 402 is formed between the outer peripheral wall of the second tube body 330 and the end of the first tube body 320, which can prevent refrigerant leakage and improve sealing performance.

[0084] High-frequency induction brazing utilizes a high-frequency alternating current to generate induced eddy currents on the second tube 330 and the first tube 320, thereby achieving localized rapid heating. After the brazing filler metal melts, a second sealing brazing seam 402 is formed. High-frequency induction brazing features concentrated heating, high speed, small heat-affected zone, and high degree of automation. Flame brazing utilizes the flame of combustible gas combustion for heating, causing the brazing filler metal to melt and connect. Flame brazing equipment is simple and suitable for welding in various complex positions. For example, in this solution, one end of the second tube 330 is inserted into the second connecting section 322 and connected to the second connecting section 322 by high-frequency induction brazing.

[0085] In one embodiment, the first tube body 320 further includes a transition section 323, which connects the first connecting section 321 and the second connecting section 322. The inner diameter and outer diameter of the transition section 323 are both gradually widened along the direction from the first connecting section 321 to the second connecting section 322.

[0086] It is understandable that the inner and outer diameters of the transition section 323 are gradually widened along the direction from the first connecting section 321 to the second connecting section 322. This helps to avoid abrupt changes in the cross-sectional area of ​​the transition section 323 that could generate eddies and airflow noise, facilitates manufacturing, and reduces stress concentration, thereby improving the energy efficiency of the compression device 10 and reducing noise.

[0087] In one embodiment, the first connecting segment 321 and the second connecting segment 322 are arranged in a cylindrical shape. This arrangement can ensure the dimensional consistency of the first connecting segment 321 and the second connecting segment 322, which is convenient for processing and manufacturing.

[0088] Please see Figure 6 and Figure 7In one embodiment, the second pipe body 330 includes a first pipe segment 331, a bend segment 332, and a second pipe segment 333 connected in sequence. The first pipe segment 331 is connected to the first pipe body 320, and the second pipe segment 333 is connected to the liquid storage outlet 210. The extension directions of the first pipe segment 331 and the second pipe segment 333 intersect. The minimum outer diameter of the first pipe segment 331 and the second pipe segment 333 is D. The minimum distance between the end of the first pipe segment 331 away from the bend segment 332 and the central axis of the second pipe segment 333 along the extension direction of the first pipe segment 331 is L1. The minimum distance between the end of the second pipe segment 333 away from the bend segment 332 and the central axis of the first pipe segment 331 along the extension direction of the second pipe segment 333 is L2. D, L1, and L2 satisfy: L1 ≥ 1.5D, L2 ≥ 1.5D.

[0089] It is understood that the bend section 332 is used to change the direction of the pipeline. The bend section 332 connects the first pipe section 331 and the second pipe section 333. The extension directions of the first pipe section 331 and the second pipe section 333 intersect. For example, the first pipe section 331 extends horizontally, and the second pipe section 333 extends vertically. This solution achieves a spatially staggered connection between the air intake 121 and the liquid storage outlet 210 through the bend section 332, which is beneficial to improving the compactness of the structural layout of the compression device 10.

[0090] The minimum outer diameter of the first pipe section 331 and the second pipe section 333 is D. That is, the outer diameters of the first pipe section 331 and the second pipe section 333 can be the same or different. The minimum nominal outer diameter of the first pipe section 331 and the second pipe section 333 is D. Along the extension direction of the first pipe segment 331, the minimum distance between the end of the first pipe segment 331 away from the bend segment 332 and the central axis of the second pipe segment 333 is L1. L1 reflects the extension length of the bend segment 332 in the extension direction of the first pipe segment 331. L1≥1.5D ensures that the bend segment 332 has a sufficient bending radius. If L1 is too small, the bending radius of the bend segment 332 will be too small, resulting in the pipe wall of the bend segment 332 being too thin after bending. This solution can ensure the structural strength of the pipe wall of the bend segment 332. Along the extension direction of the second pipe segment 333, the minimum distance between the end of the second pipe segment 333 away from the bend segment 332 and the central axis of the first pipe segment 331 is L2. L2 reflects the extension length of the bend segment 332 in the extension direction of the second pipe segment 333. L2≥1.5D ensures that the bend segment 332 has a sufficient bending radius. If L2 is too small, the bending radius of the bend segment 332 will be too small, resulting in the pipe wall of the bend segment 332 being too thin after bending. This solution can ensure the structural strength of the bend segment 332.

[0091] This scheme limits L1≥1.5D and L2≥1.5D, which limits the extension lengths of the first pipe segment 331 and the second pipe segment 333 at both ends of the second pipe body 330. The extension length of the first pipe segment 331 is the effective pipe length of the first pipe segment 331, and the extension length of the second pipe segment 333 is the effective pipe length of the second pipe segment 333. By limiting the effective pipe lengths of the first pipe segment 331 and the second pipe segment 333 to be greater than 1.5 times the minimum outer diameter of the pipe segments at both ends of the second pipe body 330, the bend segment 332 can be smoothly bent and transitioned, and the pipe wall of the bend segment 332 after bending is not too thin, thereby ensuring that the bend segment 332 has sufficient structural strength.

[0092] In one embodiment, the first pipe section 331 and the second pipe section 333 are arranged in a straight pipe shape, and the wall thickness of the first pipe section 331 and the second pipe section 333 is not less than 0.8 mm; and / or, the wall thickness of the bent pipe section 332 is not less than 0.4 mm.

[0093] It is understood that the first pipe segment 331 and the second pipe segment 333 are arranged in a straight pipe shape, which facilitates processing and manufacturing; and the pipe wall thickness is not less than 0.8mm, ensuring the structural strength of the second pipe body 330 and preventing the wall thickness from being too thin when the second pipe body 330 is processed into a bent pipe shape, so that there is sufficient safe wall thickness even in the bent pipe area. For example, the pipe wall thickness of the first pipe segment 331 and the second pipe segment 333 can be 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 13mm, 1.4mm or 1.5mm, etc., and is not limited here.

[0094] The bent pipe section 332 can be formed by bending a straight pipe. During bending, the wall thickness of the straight pipe decreases. In this design, the wall thickness of the bent pipe section 332 is not less than 0.4 mm, which is the same as the wall thickness of the bent straight pipe. This ensures that the bent pipe section 332 has sufficient structural strength, preventing corrosion and perforation when exposed outside the shell 110, thus improving the reliability of the pipe assembly 300. Furthermore, combined with the wall thickness of the first pipe section 331 and the second pipe section 333 being not less than 0.8 mm, the overall reliability of the second pipe body 330 is ensured, while also considering manufacturability, which helps reduce the production cost of the second pipe body 330.

[0095] This application also proposes a heat exchange system including a compression device 10. The specific structure of the compression device 10 is as described in the above embodiments. Since this heat exchange system adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here. Using the compression device 10 of this application in the heat exchange system can reduce production costs while increasing service life.

[0096] This application also proposes a pipe assembly 300 for connecting the compression mechanism 120 of the compressor 100 and the liquid receiver 200. The pipe assembly 300 includes an installation pipe 310, a first pipe body 320, and a second pipe body 330. The installation pipe 310 is used to connect to the port 111 on the housing 110 of the compressor 100. The first pipe body 320 is inserted into the installation pipe 310, one end of the first pipe body 320 is used to connect to the suction port 121 of the compression mechanism 120, and the other end of the first pipe body 320 is connected to the installation pipe 310. One end of the second pipe body 330 is connected to the other end of the first pipe body 320, and the other end of the second pipe body 330 is used to connect to the liquid receiver outlet 210 of the liquid receiver 200. The installation pipe 310 and the first pipe body 320 are steel pipes. At least a portion of the second pipe body 330 is located outside the first pipe body 320 and the installation pipe 310, and the second pipe body 330 is a stainless steel pipe.

[0097] In the technical solution of this application, the installation pipe 310 and the first pipe body 320 are steel pipes. Compared with copper pipes, this reduces material costs and improves the structural stability of the pipe assembly 300 and its resistance to deformation at the pipe opening 111. This allows the pipe assembly 300 to better withstand the vibration of the heat exchange system and the stress in the pipeline, thereby improving the sealing reliability and fatigue life of the pipe assembly 300's connections. At least a portion of the second pipe body 330 is located outside the first pipe body 320 and the installation pipe 310. The second pipe body 330 is made of stainless steel. Compared with copper pipes, this reduces material costs and allows the second pipe body 330 exposed outside the shell 110 to effectively resist the erosion of corrosive media. This improves the corrosion resistance and rust resistance of the portion of the pipe assembly 300 exposed outside the shell 110, thus increasing the service life of the pipe assembly 300. Therefore, the technical solution of this application helps reduce the material cost of the pipe assembly 300 and increase its service life, thereby reducing the production cost of the compression device 10 while increasing its service life. The other technical effects achieved by the technical solution in this embodiment are the same as those in the foregoing embodiments, and will not be described in detail here.

[0098] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A compression device, characterized in that, include: A compressor includes a housing and a compression mechanism, the housing having an inlet, and the compression mechanism being disposed within the housing and having an intake port; A liquid reservoir is disposed outside the housing and has a liquid outlet; The tube assembly includes an installation tube, a first tube body, and a second tube body. The installation tube is connected to the tube opening. The first tube body is inserted into the installation tube, with one end of the first tube body connected to the air intake and the other end connected to the installation tube. One end of the second tube is connected to the other end of the first tube, and the other end of the second tube is connected to the liquid storage outlet; the installation tube and the first tube are steel pipes; at least a portion of the second tube is located outside the first tube and the installation tube, and the second tube is a stainless steel pipe.

2. The compression device as described in claim 1, characterized in that, The other end of the second tube is inserted into the liquid storage outlet. The second tube is connected to the liquid storage container by high-frequency induction brazing or flame brazing. A first sealing brazing seam is formed between the outer peripheral wall of the second tube and the liquid storage container.

3. The compression device as described in claim 2, characterized in that, The second tube body and the liquid reservoir are welded together by brass flux-cored solder to form the first sealing seam, which is arranged in a ring around the outer peripheral wall of the second tube body.

4. The compression device as described in claim 1, characterized in that, One end of the second tube is inserted into the first tube. The second tube and the first tube are connected by high-frequency induction brazing or flame brazing. A second sealing brazing seam is formed between the outer peripheral wall of the second tube and the end of the first tube.

5. The compression device as described in claim 4, characterized in that, The second tube body is welded to the first tube body by brass flux-cored brazing filler metal to form the second sealing seam, which is arranged in a ring around the outer peripheral wall of the second tube body.

6. The compression device as claimed in claim 1, characterized in that, The other end of the first tube extends out of the mounting tube. The first tube and the mounting tube are connected by high-frequency induction brazing or flame brazing. A third sealing brazing seam is formed between the outer peripheral wall of the first tube and the end of the mounting tube.

7. The compression device as claimed in claim 6, characterized in that, The first tube body and the mounting tube are welded together by brass flux-cored brazing filler metal to form the third sealing seam, which is arranged in a ring around the outer peripheral wall of the first tube body.

8. The compression device as claimed in claim 1, characterized in that, The mounting tube is bent outward at one end near the housing to form a flange, which abuts against the inner side of the tube opening. The mounting tube and the housing are connected by high-frequency induction brazing or flame brazing, and a fourth sealing brazing seam is formed between the outer peripheral wall of the mounting tube and the housing.

9. The compression device as claimed in claim 8, characterized in that, The mounting tube and the housing are welded together by brass flux-cored brazing filler metal to form the fourth sealing seam, which is arranged in a ring around the outer peripheral wall of the mounting tube.

10. The compression device as claimed in claim 1, characterized in that, The second tube is welded to the reservoir and the first tube respectively using brass flux-cored solder. The mounting tube is welded to the first tube and the shell respectively using brass flux-cored solder. The brass flux-cored solder includes a brass outer sheath and a flux core filled in the brass outer sheath. The brass outer sheath has a soldering opening with a width not greater than 0.5 mm.

11. The compression device as claimed in claim 1, characterized in that, The second tube is a stainless steel tube with a carbon content of no more than 0.03%; And / or, the hardness of the second tube is 100-210 Hv.

12. The compression device as claimed in claim 11, characterized in that, The second tube is a 304L stainless steel tube.

13. The compression device as claimed in claim 1, characterized in that, The first tube body includes a first connecting section and a second connecting section connected together. The inner diameter of the first connecting section is smaller than the inner diameter of the second connecting section. The first connecting section is inserted into the air intake hole and is interference-fitted with the air intake hole. Sealing oil is provided between the first connecting section and the hole wall of the air intake hole. One end of the second tube body is inserted into the second connecting section and is welded to the second connecting section by high-frequency induction brazing or flame brazing.

14. The compression device as claimed in claim 13, characterized in that, The first pipe body further includes a transition section, which connects the first connecting section and the second connecting section. The inner diameter and outer diameter of the transition section are both gradually widened along the direction from the first connecting section to the second connecting section. And / or, the first connecting segment and the second connecting segment are arranged in a cylindrical shape.

15. The compression device according to any one of claims 1 to 14, characterized in that, The second pipe body includes a first pipe segment, a bend segment, and a second pipe segment connected in sequence. The first pipe segment is connected to the first pipe body, and the second pipe segment is connected to the liquid storage outlet. The extension directions of the first pipe segment and the second pipe segment intersect. The minimum outer diameter of the first pipe segment and the second pipe segment is D. Along the extension direction of the first pipe segment, the minimum distance between the end of the first pipe segment away from the bend and the central axis of the second pipe segment is L1; along the extension direction of the second pipe segment, the minimum distance between the end of the second pipe segment away from the bend and the central axis of the first pipe segment is L2; ​​D, L1 and L2 satisfy: L1≥1.5D, L2≥1.5D.

16. The compression device as claimed in claim 15, characterized in that, The first pipe section and the second pipe section are arranged in a straight pipe shape, and the wall thickness of the first pipe section and the second pipe section is not less than 0.8 mm; And / or, the wall thickness of the bend is not less than 0.4 mm.

17. A heat exchange system, characterized in that, Includes the compression device as described in any one of claims 1 to 16.

18. A pipe assembly for connecting the compression mechanism of a compressor and a liquid receiver, characterized in that, include: The mounting tube is used to connect to the port on the compressor housing; A first tube is inserted into the mounting tube. One end of the first tube is connected to the suction port of the compression mechanism, and the other end of the first tube is connected to the mounting tube. The second tube has one end connected to the other end of the first tube, and the other end of the second tube is used to connect to the liquid storage outlet of the liquid reservoir; the mounting tube and the first tube are steel pipes; at least a portion of the second tube is located outside the first tube and the mounting tube, and the second tube is a stainless steel pipe.

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