Composite heat exchange tube and production equipment thereof

Abstract

This utility model discloses a composite heat exchange tube and its production equipment, including: a substrate pretreatment device, an inner and outer tube insertion device, a filler layer coating device, and a composite tube drawing device. The inner and outer tube insertion device inserts the inner tube into the outer tube. The filler layer coating device is located in the middle of the inner and outer tube insertion device. During the insertion process, the filler layer coating device coats the outer surface of the inner tube. The outlet of the inner and outer tube insertion device is equipped with a composite tube drawing device for drawing the inserted heat exchange tube. The composite heat exchange tube proposed in this utility model solves the problems of high cost, short lifespan, and easy corrosion of existing stainless steel heat exchange tubes through innovative structural design and process optimization.

Description

Technical Field

[0001] This utility model relates to the field of pipe processing equipment technology, and in particular to a composite heat exchange tube and its production equipment. Background Technology

[0002] As the core component of a heat exchanger, heat exchange tubes primarily function to transfer heat between hot and cold fluids through the tube wall, and are widely used in industries such as industrial, energy, chemical, and refrigeration. However, in actual operating conditions, the media in contact with heat exchange tubes often contain corrosive components such as acids, alkalis, and salts, which can easily lead to corrosion problems over long-term operation, including uniform corrosion, pitting corrosion, and stress corrosion cracking. These problems can not only cause thinning of the tube wall but also perforation. As the core component of a heat exchange system, the failure risk of heat exchange tubes directly affects the safety and economy of industrial equipment. To address corrosion risks, existing technologies typically use corrosion-resistant stainless steel heat exchange tubes instead of traditional carbon steel heat exchange tubes. The corrosion resistance of stainless steel mainly stems from the passivation film formed on its surface. When stainless steel contains at least 10.5% chromium, a very thin, dense, and stable chromium oxide film (Cr2O3) forms on the surface. This film effectively isolates the stainless steel from direct contact with corrosive media. The formation of the passivation film is a spontaneous oxidation process; when stainless steel is exposed to an oxygen-containing environment, chromium preferentially combines with oxygen to form an oxide layer. This oxide film not only prevents further oxidation reactions but also alters the electrode potential of stainless steel, raising it from negative to positive, thereby inhibiting electrochemical corrosion. While stainless steel heat exchange tubes possess excellent corrosion resistance, their production cost is high (approximately 50,000-60,000 RMB / ton), and they still face the risk of localized corrosion under complex operating conditions (such as high temperature and high chloride ion environments), leading to a shortened lifespan (1-2 years) and further increasing operating costs. Furthermore, pure stainless steel tubes have poor thermal conductivity, which may affect heat exchange efficiency. Therefore, the industry urgently needs a low-cost heat exchange tube solution that also offers good corrosion resistance. Utility Model Content

[0003] In order to solve the problems existing in the prior art, this utility model provides a composite heat exchange tube and its production equipment to solve the existing technical problems.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] This utility model provides a production equipment for composite heat exchange tubes, including: a substrate pretreatment device, an inner and outer tube insertion device, a filler layer coating device, and a composite tube drawing device. The inner and outer tube insertion device inserts the inner tube into the outer tube. The filler layer coating device is provided in the middle of the inner and outer tube insertion device. During the insertion process of the inner and outer tube insertion device, the filler layer coating device coats the outer surface of the inner tube. The outlet of the inner and outer tube insertion device is provided with a composite tube drawing device for drawing the heat exchange tube after insertion.

[0006] Preferably, the composite tube pulling device includes a pre-tension self-balancing traction head, a drive slide, and a mold. The moving end of the drive slide is connected to the pre-tension self-balancing traction head. The pre-tension self-balancing traction head includes multiple sets of circumferentially distributed wedge-shaped sliders, wear-resistant pads, and disc spring buffer modules. A mold is fixedly installed at one end of the drive slide.

[0007] Preferably, the inlet of the inner and outer tube sleeve device receives the inner tube after the surface has been treated by the substrate pretreatment equipment, and the inner tube to be processed enters from the inlet of the substrate pretreatment equipment.

[0008] Preferably, the filler coating equipment includes: a coating support, on which a recovery tank and a rotary coating machine are installed. The recovery tank is equipped with a nozzle of a mixing and feeding extruder and a coating cylinder of the rotary coating machine. The mixing and feeding extruder extrudes filler material through the nozzle and adheres it to the surface of the inner tube. The rotary coating machine drives the coating cylinder to rotate, so as to coat the filler material adhered to the surface of the inner tube of the substrate evenly.

[0009] This utility model also provides a composite heat exchange tube, comprising: an inner tube, an outer tube disposed on the outside of the inner tube, and a filling layer between the inner tube and the outer tube.

[0010] Preferably, the filler layer is a filler material applied to the surface of the substrate using a filler layer application device.

[0011] Preferably, the outer tube is a thin-layer stainless steel tube.

[0012] The beneficial effects of this utility model are:

[0013] The composite heat exchange tube proposed in this invention solves the problems of high cost, short lifespan, and easy corrosion of existing stainless steel heat exchange tubes through innovative structural design and process optimization, as detailed below:

[0014] The base layer uses low-cost carbon steel pipes: By using carbon steel pipes (costing approximately 1 / 10th that of stainless steel) as the base material, traditional all-stainless steel heat exchanger tubes are replaced, significantly reducing material costs. The stainless steel layer is designed with a thinner layer: the stainless steel layer is only 0.1-2mm thick (far thinner than traditional all-stainless steel pipes), further reducing the amount of stainless steel used and keeping costs under control. Compared to all-stainless steel heat exchanger tubes, composite heat exchanger tubes can reduce costs by 50%-70% while retaining the corrosion resistance of stainless steel, giving composite heat exchanger tubes a service life similar to pure stainless steel heat exchanger tubes.

[0015] Adding thermally conductive particles, such as graphene, silicon carbide, and silver powder, to modified thermally conductive materials can reduce the interfacial thermal resistance between the stainless steel layer and the substrate, thereby improving heat transfer efficiency.

[0016] From substrate pretreatment to final drawing, each process is linked with equipment to achieve continuous production, reducing manual intervention and improving process stability. Attached Figure Description

[0017] The above-described aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of the structure of the composite heat exchange tube according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of the production equipment for the composite heat exchange tube according to an embodiment of this utility model;

[0020] Figure 3 This is a schematic diagram of the structure of the composite heat exchange tube and its production equipment, including the inner and outer tube sleeve device and the filler layer coating device, according to an embodiment of this utility model.

[0021] Figure 4 This is a schematic diagram of the structure of the filling layer coating equipment of the composite heat exchange tube and its production equipment according to an embodiment of the present utility model;

[0022] Figure 5 This is a schematic diagram of the composite heat exchange tube and the composite tube drawing device of the production equipment of the present invention.

[0023] Explanation of reference numerals in the attached figures

[0024] exist Figures 1-5 In the middle, there are: inner tube 1; filler layer 2; outer tube 3; substrate pretreatment equipment 4; inner and outer tube sleeve device 5; filler layer coating equipment 6; composite tube drawing device 7; inner tube sleeve device 8; outer tube clamping device 9; nozzle 10; rotary coating machine 11; coating cylinder 12; recovery tank 13; coating support 14; mixing and feeding extruder 15; drive slide 16; pre-tightening force self-balancing traction head 17; heat exchange tube 18; mold 19; and drawing machine 20. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] A composite heat exchange tube includes the following structure:

[0027] Inner tube 1 (or base layer, substrate): A metal base pipe, such as carbon steel pipe, Corten steel pipe, ND steel pipe, etc., can also be selected. Other metal pipes with high structural strength, high temperature resistance, good thermal conductivity, and certain corrosion resistance can also be used. Furthermore, carbon steel pipe, as the base layer, has high strength, can withstand high pressure and high temperature, has good durability, and low cost. The cost of carbon steel pipe is only 1 / 10 of that of stainless steel, and it has high thermal conductivity (approximately 50 W / m·K), which is superior to stainless steel (approximately 16 W / m·K).

[0028] Filler Layer 2: Filler Layer 2 is a layer of filler material applied to the surface of the substrate by the filler layer coating device 6. It fills the gap between the substrate and the stainless steel layer, reducing the voids between them. Filler Layer 2 blocks the migration path of corrosive media and prevents the formation of conductive channels between the substrate and the stainless steel layer by electrolytes, thus avoiding electrochemical corrosion. Furthermore, Filler Layer 2 is a modified thermally conductive material, reducing the interfacial thermal resistance between the stainless steel layer and the substrate. The modified thermally conductive material can be prepared by adding thermally conductive particles, nanomaterials, metal powders, etc., to the base thermally conductive material; for example, using silicone grease or methylphenyl silicone oil as the base thermally conductive material, and adding single or combined materials such as potassium metal, graphene, graphite, silicon carbide, silver, copper powder, and nanoparticles. It is important to note that to avoid electrochemical corrosion between the stainless steel and the base tube, the base thermally conductive material must be non-conductive.

[0029] Outer tube 3 (or stainless steel layer): A thin-layer stainless steel tube, with a thickness between 0.1-2mm, is used. Compared with traditional all-stainless steel tubes (2-4mm), this saves 50%-70% of material. It is composited with the base layer through a drawing process. The outer stainless steel layer has strong structural rigidity, making it less prone to damage or breakage during transportation and installation. Moreover, during the welding connection of the composite heat exchange tube 18 to the tube box plate, since both the inner and outer layers of the rigid tube are made of rigid materials, they can be welded to the tube box plate. During the welding process, they are naturally welded together as one unit, and there will be no end breakage due to the difference in the coefficient of thermal expansion of the materials.

[0030] A composite heat exchanger tube production equipment includes the following components:

[0031] Substrate pretreatment equipment 4: Typically, shot blasting machines, sandblasting machines, and polishing and grinding machines are used to treat the surface of the substrate, ensuring strong bonding with the filler layer 2 and the stainless steel layer. Its core function is to clean and roughen the surface of the substrate, which is the first process in the preparation of composite heat exchange tubes. High-purity cast steel shot (0.8-1.2mm particle size) is used for high-speed blasting, achieving a surface roughness of Ra 3.2-6.3μm, removing oxide scale, rust, and impurities. The surface cleanliness after treatment must meet ISO 8501-1Sa 2.5 standard.

[0032] Inner and outer tube insertion device 5: A insertion machine inserts the substrate inner tube 1 into the stainless steel outer tube 3 to form a composite tube structure. During insertion, eccentricity should be avoided to prevent stress concentration. The inner and outer tube insertion device 5 includes an outer tube 3 clamping device and an inner tube insertion device 8. The inner tube insertion device 8 uses a motor-driven threaded screw mechanism to push the substrate inner tube 1 into the outer tube 3, with the insertion speed controlled at 0.5–5 m / min. The outer tube clamping device includes a frame with several slots fixed on it to restrict the movement of the outer tube. The inner tube insertion device 8 includes a track frame and a pushing device, which guides the substrate inner tube along the track to insert it into the outer tube.

[0033] The filler layer coating equipment 6 uses a rotary coating machine 11 (rotary coating) to uniformly coat the inner and outer layers of the composite pipe with filler material, forming a filler layer 2. The filler layer coating equipment 6 is positioned between the outer pipe clamping device 9 and the inner pipe insertion device 8. During the insertion process of the inner pipe 1 into the outer pipe 3, the outer surface of the inner pipe 1 is rotary coated. Its core function is to ensure that the substrate surface is uniformly coated with filler material before the stainless steel layer is inserted. The filler layer coating equipment 6 includes two processes: extrusion and coating of the filler layer 2 material, and is equipped with a recycling device to collect and process the dripping filler layer 2 material for reuse. Further, the rotary coating machine 11 includes a coating support 14, on which a recycling tank 13 is installed. The recycling tank 13 is equipped with the nozzle 10 of the mixing and feeding extruder 15 and the coating cylinder 12 of the rotary coating machine 11. The mixing and feeding extruder 15 extrudes the filler layer 2 material through the nozzle 10 and adheres it to the surface of the inner tube 1 of the substrate. The rotary coating machine 11 drives the coating cylinder 12 to rotate and coat the filler layer 2 material adhered to the surface of the inner tube 1 of the substrate evenly.

[0034] Composite tube pulling device 7: The heat exchange tube 18 after being sleeved is pulled by the tube pulling machine 20, so that the stainless steel layer is reduced in diameter and tightly bonded to the base layer. The composite tube pulling device 7 includes a pre-tightening force self-balancing traction head 17, a drive slide 16, and a mold 19. The moving end of the drive slide is connected to the pre-tightening force self-balancing traction head. The pre-tightening force self-balancing traction head is characterized by including 6 sets of circumferentially distributed wedge-shaped sliders, UHMWPE wear-resistant pads, and disc spring buffer modules, which realize dynamic balance of clamping force and impact buffering through mechanical-hydraulic coupling. The mold 19 is fixedly installed at one end of the drive slide. The pre-tightening force self-balancing traction head 17 clamps the sleeved composite heat exchange tube 18 (the heat exchange tube 18 processed by the inner and outer tube sleeve device 5). The drive slide 16 pulls one end of the composite heat exchange tube 18 away from the mold 19 until the other end of the tube passes through the mold 19.

[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A production equipment for composite heat exchange tubes, characterized in that: include: The system includes a substrate pretreatment device, an inner and outer tube insertion device, a filler layer coating device, and a composite tube drawing device. The inner and outer tube insertion device inserts the inner tube into the outer tube. A filler layer coating device is installed in the middle of the inner and outer tube insertion device. During the insertion process, the filler layer coating device coats the outer surface of the inner tube. The outlet of the inner and outer tube insertion device is equipped with a composite tube drawing device for drawing the heat exchange tube after insertion.

2. The production equipment for composite heat exchange tubes according to claim 1, characterized in that: The composite tube pulling device includes a pre-tension self-balancing traction head, a drive slide, and a mold. The moving end of the drive slide is connected to the pre-tension self-balancing traction head. The pre-tension self-balancing traction head includes multiple sets of circumferentially distributed wedge-shaped sliders, wear-resistant pads, and disc spring buffer modules. A mold is fixedly installed at one end of the drive slide.

3. The production equipment for composite heat exchange tubes according to claim 1, characterized in that: The inlet of the inner and outer tube insertion device receives the inner tube after the surface has been treated by the substrate pretreatment equipment, and the inner tube to be processed enters from the inlet of the substrate pretreatment equipment.

4. The production equipment for composite heat exchange tubes according to claim 1, characterized in that: The filler coating equipment includes: a coating support, on which a recovery tank and a rotary coating machine are installed. The recovery tank is equipped with a nozzle of a mixing and feeding extruder and a coating cylinder of the rotary coating machine. The mixing and feeding extruder extrudes filler material through the nozzle and adheres it to the surface of the inner tube. The rotary coating machine drives the coating cylinder to rotate, so as to coat the filler material adhered to the surface of the inner tube of the substrate evenly.

5. A composite heat exchange tube, comprising: The inner tube is characterized in that: an outer tube is provided on the outside of the inner tube, and a filling layer is filled between the inner tube and the outer tube.

6. The composite heat exchanger tube according to claim 5, characterized in that: The filler layer is a layer of filler material applied to the surface of the substrate using a filler layer coating device.

7. The composite heat exchanger tube according to claim 5, characterized in that: The outer tube is a thin-layer stainless steel tube.

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