Nickel large-diameter continuous lotus-root-shaped heat exchanger, integrated forming mold and method

Abstract

The invention discloses a nickel large-diameter continuous lotus-root-shaped heat exchanger and an integral forming die and method, the heat exchanger comprises an outer pipe and an inner pipe, and the inner pipe is of a continuous lotus-root-shaped structure and is composed of a plurality of continuous lotus-root-shaped short sections. Each lotus-root-shaped short section is provided with a straight barrel section and conical opening sections which are located at the two ends of the straight barrel section and shrink inwards, and the adjacent lotus-root-shaped short sections are connected through the conical opening sections. The integrated forming die comprises a frame body, a driving component and a die body. According to the large-diameter continuous lotus-root-shaped heat exchanger, the inner pipe is of a continuous integrated lotus-root-shaped structure, and welding cracks of nickel metal are effectively avoided. Meanwhile, the inner pipe of the continuous lotus-root-shaped structure enables flowing of fluid entering the inner pipe to be changed compared with a straight pipe, for example, radial flowing change is achieved through the lotus-root-shaped structure of the inner wall of the inner pipe, and therefore the heat exchange effect of the heat exchanger is improved under the limitation of the specification of the outer pipe.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a nickel-made large-diameter continuous lotus-shaped heat exchanger, an integral molding die, and a method. Background Art

[0002] A heat exchanger, also known as a heat exchanger, is an energy-saving device that transfers heat between two or more fluids at different temperatures. Its basic function is to transfer heat between fluids at different temperatures. Through a heat exchanger, part of the heat of the hot fluid can be transferred to the cold fluid, causing the cold fluid to heat up and the hot fluid to cool down, thereby achieving the desired temperature state for each. Heat exchangers play an important role in improving energy utilization, controlling process flow temperature, regulating ambient temperature, and protecting equipment. In the industrial field, heat exchangers can be used in chemical reactions, distillation, condensation and other processes to control reaction temperature, separate mixtures, or condense gas products; in the power industry, heat exchangers are used in boiler feed water heating and other links in power plant cooling to improve power generation efficiency; and also include applications such as high-temperature process cooling in metallurgy and metal processing, sterilization and cooling of food and pharmaceuticals, and heat recovery and condensation in refrigeration and air conditioning.

[0003] Currently, heat exchangers can be classified according to various standards. For example, they are classified by the shape and structure of the heat transfer surface into tubular heat exchangers and plate heat exchangers, and by the materials used into metallic and non-metallic materials. In the chemical and petroleum industries, corrosion resistance is a key characteristic of heat exchangers. Currently, metals with good corrosion resistance include titanium and nickel. Nickel outperforms titanium in terms of corrosion resistance, high temperature resistance, and cost. Consequently, heat exchangers made of nickel are widely used in specialized heat exchange applications.

[0004] In the industrial field, metal tube heat exchangers are widely used, such as Figure 1 The figure shows a currently used tubular heat exchanger structure, which includes an inner tube and an outer tube. The port of the inner tube is welded to the inner wall of the outer end to form a heat exchange cavity between the inner and outer tubes. The inlet and outlet are set on the diagonal surface of the outer tube. The heat exchange process is as follows Figure 1As shown, one liquid is introduced from the left port of the outer tube, into the inner tube, and flows out from one side of the outer tube, while the second liquid enters from the inlet on the outer tube and flows out in the heat exchange chamber toward the outlet, achieving heat exchange between the two fluids through the side wall of the inner tube. The outer and inner tubes of this common tubular heat exchanger are both straight tube structures, which makes the flow rate of the fluid inside them relatively fast, resulting in low heat exchange efficiency during the flow cycle of the fluid in the heat exchanger, and the set heat exchange effect cannot be achieved. Therefore, the heat exchange effect is currently improved by increasing the diameter of the inner and outer tubes of the heat exchanger to increase the surface area. However, for equipment with limited installation space, the increased specifications of the heat exchanger will make it difficult to assemble the heat exchanger smoothly, and the heat exchange efficiency cannot be effectively improved. Summary of the Invention

[0005] In response to the above-mentioned problems, the present invention aims to provide a nickel-made large-diameter continuous lotus-shaped heat exchanger, an integrated molding mold and a method. The inner tube of the heat exchanger with a continuous lotus-shaped structure prepared by the mold can effectively increase the heat exchange area and efficiency of the heat exchanger under the condition of limited outer tube size; at the same time, the mold and method can achieve the formation of the inner tube with a lotus-shaped structure on the basis of eliminating splicing welds. This method can be applied to the molding of inner tubes of large-diameter heat exchangers and ensure the fluid pressure bearing capacity.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a nickel-made large-diameter continuous lotus-shaped heat exchanger, comprising an outer tube and an inner tube, a closed heat exchange cavity is formed between the outer tube and the inner tube, and an inlet and an outlet that are connected to the heat exchange cavity are sequentially arranged on the diagonal upper and lower surfaces of the outer tube. The outer tube is a straight tube structure, and the inner tube is a continuous lotus-shaped structure, which is composed of a plurality of continuous lotus-shaped short sections.

[0007] Preferably, each of the lotus-shaped short sections comprises a straight section and inwardly contracted tapered sections at both ends of the straight section, and adjacent lotus-shaped short sections are connected by the tapered sections.

[0008] Preferably, each of the cone-mouth sections is an arc structure, and is in arc transition with the straight cylinder section, and the adjacent cone-mouth sections are connected with arc transition.

[0009] An integral molding die for a nickel-made large-caliber continuous lotus-shaped heat exchanger, comprising: The frame is composed of symmetrical vertical beams and a horizontal beam at the top; A driving member is provided below the crossbeam to realize vertical driving; The mold body includes an upper mold arranged below the driving member and a lower mold located on the ground below the upper mold. The upper mold and the lower mold are both semi-circular cylindrical structures, and conical protrusions are correspondingly arranged above and below the upper mold and the lower mold to fit the tapered mouth sections where adjacent lotus-shaped short sections are connected. The conical protrusions are V-shaped structures with arc transitions.

[0010] Preferably, a plurality of ribs are provided at axial intervals on the back side of the upper mold and connected to the driving member, and a plurality of the ribs are provided on the back side of the lower mold and fixed on the ground.

[0011] Preferably, transverse limiting rods are provided on the left and right sides of the rib surface of the lower die for vertically limiting the downward movement of the upper die, and the top ends of the transverse limiting rods can penetrate into the adjacent ribs of the upper die.

[0012] Preferably, axial limiting rods for axially limiting the downward movement of the upper mold are provided on both the left and right sides of the front and rear end surfaces of the lower mold.

[0013] Preferably, a tube support frame is provided on both sides of the lower mold, and support rollers are provided on the tube support frame at intervals along the axial direction of the inner tube.

[0014] Preferably, an assembly rod is hinged on the transverse limiting rod, and a heating gun is axially slidably assembled on the assembly rod.

[0015] A method for integrally forming a nickel-made large-diameter continuous lotus-shaped heat exchanger comprises the following steps: S1. Place the straight tube blank for forming the inner tube on the supporting roller of the tube body support frame; S2, driving the straight tube billet to move on the supporting roller, and making its end extend into the lower die to a certain length; S3, surface heating the straight tube blank and the portion of the tapered protrusion exposed outside the lower die by axial movement and vertical deflection of the heating gun; S4. After the surface of the straight tube billet is heated to the thermal deformation temperature, the driving member moves downward, driving the upper die to press the straight tube billet downward. The straight tube billet is squeezed by the conical protrusions of the upper die and the lower die, forming a prototype of a tapered mouth section on its surface; S5, driving the upper die to move downward multiple times, and rotating the straight tube blank at the same time, so that the tapered section on the surface of the straight tube blank is formed; S6. After the single tapered section is formed, the straight tube billet is driven to move on the supporting rollers, and steps S3-S5 are repeated to form the straight tube billet into an integral inner tube with a lotus root-shaped structure; S7. Insert the inner tube into the outer tube, and weld the port of the inner tube and the inner wall of the outer tube to seal, thereby forming the continuous lotus-shaped heat exchanger.

[0016] The beneficial effects of the present invention are as follows: the nickel-made, large-diameter, continuous lotus-shaped heat exchanger disclosed herein has a continuous, integrated lotus-shaped inner tube, effectively preventing weld cracks in the nickel metal. Furthermore, the continuous lotus-shaped inner tube can alter the flow of the fluid entering it compared to a straight tube. For example, the lotus-shaped structure of the inner tube wall achieves radial flow variation, thereby improving the heat exchange efficiency of the heat exchanger within the constraints of the outer tube specifications.

[0017] The one-piece forming mold disclosed in the present application forms a V-shaped structure and connected tapered sections on a straight tube blank by mechanical pressing, so that the inner tube forms a continuous lotus-shaped structure, avoiding the problem of a significant increase in welds of the inner tube formed by welding multiple short sections and affecting its pressure-bearing capacity.

[0018] The disclosed one-piece molding method can effectively avoid the problems of cracks and breakage caused by pressing during the process of forming a lotus-shaped inner tube by using a pressing method with gradually increasing depth and local heating of the pressing part. At the same time, the combination of the one-piece molding mold and the method can realize the rolling of large-diameter inner tubes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a diagram of the inner and outer tubes and combined structure of a current conventional tubular heat exchanger.

[0020] Figure 2 This is a structural diagram of a single lotus root-shaped short section of the present invention.

[0021] Figure 3 This is a structural diagram of the molded inner tube of the present invention.

[0022] Figure 4 For the present invention Figure 3 A magnified view of the structure at center A.

[0023] Figure 5 This is a structural diagram of the inner and outer tubes of the heat exchanger of the present invention.

[0024] Figure 6 This is the structural diagram of the heat exchanger of the present invention.

[0025] Figure 7 This is a structural diagram of the frame of the present invention.

[0026] Figure 8 This is a top view of the conical protrusions in the upper and lower molds of the present invention.

[0027] Figure 9 This is a diagram illustrating the pressing process of the tapered section on the inner tube of the present invention.

[0028] Figure 10 This is a diagram illustrating the horizontal lateral deflection during the downward movement of the upper mold of the present invention.

[0029] Figure 11 This is a diagram illustrating the front-to-rear axial offset between the upper die and the lower die during the downward movement of the upper die of the present invention.

[0030] Figure 12 The present invention is provided with a transverse limiting rod and an axial limiting rod as shown in the figure.

[0031] Figure 13 This is a diagram showing the gravity deflection of the inner tube during the pressing process of the tapered section of the present invention.

[0032] Figure 14 This is a diagram showing that a rod support frame is provided on one side of the lower mold in the present invention.

[0033] Figure 15 The inner tube of the tapered section of the present invention moves downward relative to the lower die during press forming.

[0034] Figure 16 This is a diagram illustrating the bending caused by the inner tube being supported by the tube support frame during the downward movement of the inner tube of the present invention.

[0035] Figure 17 The present invention provides a hinged rod so that the tube body support frame can move downward synchronously when the inner tube is pressed downward.

[0036] Figure 18 The present invention is provided with a driving plate and a set square diagram.

[0037] Figure 19 The present invention provides a driving plate and a triangular plate to synchronously drive the tube body support frame to move downward during the downward movement of the upper die.

[0038] Figure 20 This is a diagram showing that tube support frames are provided on both sides of the lower mold in the present invention.

[0039] Figure 21 This is a diagram showing that a ruler is provided on one side of the inner tube in the direction of movement.

[0040] Figure 22 A diagram of an articulated assembly rod is provided for the present invention.

[0041] Figure 23 This is a diagram showing a heating gun being installed on an assembly rod of the present invention and heating the pressing portion of the inner tube.

[0042] Figure 24 This is a physical illustration of the one-piece molding die of the present invention.

[0043] Figure 25 This is a physical illustration of the conical protrusions inside the upper and lower molds of the present invention.

[0044] Figure 26 This is a physical illustration of the inner tube formed by compression molding according to the present invention.

[0045] Figure 27 This is a physical illustration of the tapered section pressed under a heated state according to the present invention.

[0046] Figure 28 This is a physical diagram of the heat exchanger of the present invention.

[0047] Figure 29 This is a physical diagram of the heat exchanger of the present invention.

[0048] In the figure: 1-outer tube; 1a-inlet; 1b-outlet; 2-inner tube; a-heat exchange chamber; 21-lotus root shaped short section; 21a-straight cylinder section; 21b-tapered section; 3-frame; 31-vertical beam; 32-cross beam; 4-hydraulic cylinder; 51-upper die; 52-lower die; 5a-conical protrusion; 61-rib plate; 62-horizontal plate; 71-lateral limit rod; 72-axial limit rod; 8-tube support frame; 81-cross rod; 82-vertical rod; 821-sleeve section; 822-screw section; 83-support roller; 84-hinged rod; 85-vertical limit plate; 9-drive plate; 91-triangular plate; 10-support rod; 11-sleeve; 12-ruler; 13-vertical plate; 14-assembly rod; 15-heating gun. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0050] Refer to the attached Figures 2 to 29 The nickel-made large-diameter continuous lotus-shaped heat exchanger shown in the figure includes an outer tube 1 and an inner tube 2. A closed heat exchange chamber a is formed between the outer tube 1 and the inner tube 2. An inlet 1a and an outlet 1b are sequentially provided on the diagonal upper and lower surfaces of the outer tube 1, which are connected to the heat exchange chamber a. The outer tube 1 is a straight tube structure. The present application aims to improve the heat exchange efficiency of the heat exchanger under the condition that the specifications of the outer tube 1 are limited. Figure 3 As shown, the inner tube 2 provided in the present application is a continuous lotus-shaped structure, which is composed of a continuous plurality of lotus-shaped short sections 21, and the adjacent lotus-shaped short sections 21 are an integrated structure, and are not welded (the heat exchanger disclosed in the present application is made of nickel. Since nickel metal is very prone to cracks during high-temperature welding, there is great difficulty in welding forming, especially since multiple lotus-shaped short sections 21 constitute more welding points). The lotus-shaped inner tube 2 with an integrated structure effectively avoids welding cracks of nickel metal, and thus the integrated structure is particularly suitable for non-welding forming of nickel heat exchangers.

[0051] The inner tube 2 with a continuous lotus-shaped structure can change the flow of the fluid entering it compared to a straight tube. For example, the lotus-shaped structure of the inner wall of the inner tube 2 can realize radial flow changes, thereby improving the heat exchange effect of the heat exchanger within the specification limit of the outer tube 1.

[0052] Further, if Figure 2As shown, each lotus-shaped short section 21 is composed of a straight section 21a and a tapered section 21b located at both ends of the straight section 21a. Adjacent lotus-shaped short sections 21 are connected by the tapered section 21b. The diameter of the straight section 21a is larger than that of the tapered section 21b, thereby increasing the heat exchange area of ​​the inner tube 2. At the same time, the diameter of the straight section 21a and the tapered section 21b changes, causing the flow rate of the fluid in the inner tube 2 to continuously change. Compared with the inner tube 2 with a straight tube structure, it can achieve radial mixing of the fluid, exchange heat on the side wall of the inner tube 2 through the mixing of the fluid, and thus improve the heat exchange effect of the heat exchanger as a whole from the increase in heat exchange area and the mixing of the fluid.

[0053] Further, if Figure 4 As shown, each of the cone-mouth sections 21b is an arc structure, and is in arc transition with the straight cylinder section 21a, and the adjacent cone-mouth sections 21b are connected with each other in arc transition. The inner tube 2 of the heat exchanger of the present application is formed by non-welding, that is, it is formed by mechanical external force, and the diameter of the tapered section 21b is smaller than that of the straight section 21a. Therefore, in order to avoid the problem of the tapered section 21b directly shrinking obliquely inward compared to the straight section 21a and causing fracture at the joint, the present application sets the tapered section 21b to an arc structure and transitions with the straight section 21a in an arc, which can effectively avoid the problem of the tapered section 21b directly shrinking obliquely inward under the action of mechanical external force and easily causing cracks at the joint; and the adjacent tapered sections 21b are also connected by an arc transition, that is, the problem of cracks and fractures at the corners of the oblique cross V-shaped connection is avoided. Therefore, through the arc structure of the tapered section 21b and the arc transition with the straight section 21a and the adjacent tapered section 21b, the problem of cracks and fractures during mechanical external force forming is effectively avoided, thereby ensuring the pressure bearing capacity of the inner tube 2.

[0054] According to the lotus-shaped heat exchanger disclosed in the present application, the present application also provides an integrated molding die for a nickel-made large-diameter continuous lotus-shaped heat exchanger, such as Figure 7 Shown, including: The frame 3 is composed of symmetrical vertical beams 31 and a horizontal beam 32 on the top. The vertical beams 31 and the horizontal beams 32 are preferably welded together, and the bottom end of the vertical beam 31 is preferably fixed to the ground.

[0055] A driving component, preferably a hydraulic cylinder 4 , is provided below the crossbeam 32 to achieve vertical driving.

[0056] The mold body includes an upper mold 51 disposed below the driving member, and a lower mold 52 located on the ground below the upper mold 51. The upper mold 51 and the lower mold 52 are both semi-circular cylindrical structures, and conical protrusions 5a are correspondingly disposed above and below the upper mold 51 and the lower mold 52 to fit the tapered sections 21b where adjacent lotus-shaped short sections 21 are connected. The conical protrusions 5a are V-shaped structures with arc transitions. When the lotus-shaped short sections 21 on the inner tube 2 are formed, the straight tube blank is inserted into the upper mold 51 and the lower mold 52 and is received on the conical protrusion 5a of the lower mold 52 to keep the straight tube blank horizontal. Then, the hydraulic cylinder 4 moves downward, squeezing the surface of the straight tube blank through the conical protrusions 5a of the upper mold 51 and the lower mold 52, forming a V-shaped structure and connected tapered sections 21b on the straight tube blank. The straight tube billet is moved axially to extrude a plurality of connected tapered sections 21b thereon, thereby forming the inner tube 2 of the continuous lotus-shaped heat exchanger.

[0057] In order to facilitate the fixing of the upper mold 51 and the lower mold 52 of the semicircular arc structure, as shown in FIG. Figure 7 As shown, multiple ribs 61 are axially spaced apart on the back of the upper mold 51 and connected to the drive member. Multiple ribs 61 are also provided on the back of the lower mold 52 and fixed to the ground. The ribs 61 are welded to the outer circumferences of the upper and lower molds 51, 52. The upper and lower ribs 61 are welded together by a horizontal plate 62. The upper mold 51 is connected to the hydraulic cylinder 4 via the horizontal plate 62 (either by welding or with high-strength screws). The lower mold 52 is fixed to the ground (e.g., cement) via the horizontal plate 62 (and screws), thereby securing the upper and lower molds 51, 52 in a circular arc structure.

[0058] During the downward movement of the upper die 51 and the contact between its conical protrusion 5a and the straight tube blank, due to the vertical extension error of the piston rod of the hydraulic cylinder 4 and the influence of the surface flatness of the straight tube blank, there will be a problem of left and right lateral deflection of the upper die 51 and the lower die 52 ( Figure 10 As shown), in order to avoid the problem that the deflection causes the extrusion force to deflect on the forming of the lotus-shaped inner tube 2 and affects the forming quality of the tapered section 21b, as shown Figure 12 As shown, transverse limiting rods 71 ​​are provided on the left and right sides of the surface of the ribs 61 of the lower die 52 to vertically limit the downward movement of the upper die 51. The top ends of the transverse limiting rods 71 ​​can penetrate into the adjacent ribs 61 of the upper die 51. In the process of the upper die 51 being driven downward by the hydraulic cylinder 4, before the conical protrusions 5a of the upper die 51 come into contact with the surface of the straight tube blank, the upper die 51 moves downward into the transverse limiting rods 71 ​​provided on the left and right, limiting the left and right deflection of the upper die 51 when it moves downward, as well as the deflection after it comes into contact with the straight tube blank, thereby improving the forming quality of the tapered section 21b and avoiding the problem of cracks caused by the inconsistent circumferential extrusion depth of the tapered section 21b on the inner tube 2 after the tapered section 21b is offset due to the extrusion force.

[0059] Also, in order to avoid axial deviation between the upper die 51 and the lower die 52 during the downward movement ( Figure 11 ), as shown in Figure 12 As shown, axial limiting rods 72 are provided on both the left and right sides of the front and rear end surfaces of the lower die 52 to limit the axial position of the upper die 51 when moving downward. The axial limiting rods 72 restrict the vertical alignment of the tapered protrusions 5a of the upper and lower dies 51, 52, thereby allowing the tapered sections 21b on the surface of the straight tube blank to be circumferentially connected and formed continuously, thus preventing axial misalignment of the tapered sections 21b formed by pressing and forming the upper and lower tapered sections 21b, which could lead to cracks or breakage of the inner tube 2.

[0060] Since the tapered sections 21b on the straight tube blank are pressed one by one, Figure 13 As shown in FIG, when the tapered section 21b in the center of the non-straight tube blank is pressed, the straight tube blank located outside the upper die 51 and the lower die 52 is deflected due to gravity. In addition, even if the straight tube blank is placed on the tapered protrusion 5a of the lower die 52, the straight tube blank cannot be placed horizontally due to the non-planar structure of the tapered protrusion 5a. Therefore, in order to avoid the tilt of the straight tube blank affecting the forming quality of the tapered section 21b, as shown in FIG. Figure 14 As shown, a tube support frame 8 is provided on both sides of the lower die 52, and support rollers 83 are provided on the support frame along the axial direction of the inner tube 2. Placing the straight tube blank on the support rollers 83 can keep it relatively parallel to the upper die 51 and the lower die 52, thereby effectively solving the tilt deviation and instability that may occur in the manual support state.

[0061] In order to adjust the horizontality of the straight tube blank under the support roller 83, Figure 14 As shown, the tube support frame 8 is composed of a crossbar 81 and a vertical bar 82. The support rollers 83 are spaced apart on the crossbar 81. The vertical bar 82 is a threaded telescopic sleeve structure, with the top end hingedly connected to the crossbar 81 and the bottom end rotatably mounted on the ground. By rotating the vertical bars 82 with threaded sleeve structures on both sides, the ends of the crossbar 81 can be adjusted up and down, thereby quickly adjusting the horizontality of the placed straight tube blank. The hinge hole between the vertical bar 82 and the crossbar 81 is preferably larger than the outer diameter of the hinge rod 84 to avoid adjustment interference caused by the horizontal length of the tilted vertical bar 82 being shortened and inconsistent with the spacing between the vertical bars 82 when the left and right sides are adjusted to different heights. In practice, when the vertical bars 82 are set to a horizontal position, the range of horizontal height adjustment on the left and right sides is relatively small, and horizontal adjustment can be completed within the range of the hinge gap between the vertical bar 82 and the crossbar 81.

[0062] like Figure 15As shown, in the process of the upper die 51 squeezing the straight tube blank downward through the conical protrusion 5a, the conical protrusion 5a of the lower die 52 also squeezes the straight tube blank, so that the conical protrusions 5a on the upper and lower sides are embedded in the straight tube blank, and the straight tube blank is moved downward toward the lower die 52 from the conical protrusion 5a initially placed on the lower die 52, while the support roller 83 supports the straight tube blank in a stable state. The downward movement during the pressing process will cause the support roller 83 to drive the straight tube blank upward, as shown in FIG. Figure 16 As shown in the figure, the downward pressing action and the upward supporting action cause the straight tube billet to bend. Therefore, in order to solve this problem, Figure 17 As shown, the vertical rod 82 includes a sleeve section 821 and a screw section 822, and the top end of the sleeve section 821 is hinged with a hinged rod 84, and the hinged rod 84 is hingedly connected to the cross bar 81, and a torsion spring is provided at the hinge between the hinged rod 84 and the sleeve section 821 to drive the hinged rod 84 to rotate toward the lower mold 52 (not shown in the figure, its action direction drives the hinged rod 84 toward the lower mold 52), and a vertical limiting plate 85 is provided on the side wall of the sleeve section 821 to be in contact with the side wall of the hinged rod 84.

[0063] The operation process is: After the upper die 51 moves downward and its tapered protrusion 5a contacts the upper surface of the straight tube billet (without applying downward pressure), the crossbar 81 is driven rightward, causing the hinged rod 84 to rotate and overcome the force of the torsion spring. As the hinged rod 84 deflects, its support height for the crossbar 81 decreases, and the supported straight tube billet descends, i.e., it descends synchronously with the downward pressure of the upper die 51. The rightward drive of the crossbar 81 and the pressing of the straight tube billet after the tapered protrusion 5a of the lower die 52 contacts the straight tube billet occur simultaneously. Consequently, the downward movement of the straight tube billet during the pressing process is synchronized with the downward movement of the support roller 83, thus resolving the problem of bending of the straight tube billet caused by the support of the support roller 83. After a pressing cycle is completed, the torsion spring drives the hinged rod 84 to deflect and return, and the support roller 83 supports the straight tube billet so that the ground surface and the tapered protrusion 5a of the lower die 52 are at the same height, facilitating the forward movement of the straight tube billet for the pressing of the next tapered section 21b. The vertical limit plate 85 is in contact with the hinge rod 84 after it is reset, so as to avoid the problem that the hinge rod 84 is over-reset due to the force of the torsion spring and the support height of the straight tube blank is reduced.

[0064] When the crossbar 81 is driven during the pressing process, it needs to be synchronized with the pressing process. If there is a deviation, when the downward movement depth of the straight tube billet is greater than the downward movement depth of the support roller 83, the support roller 83 still drives the straight tube billet to have a supporting force and bend; if it is less than the downward movement depth, the support roller 83 will be separated from the straight tube billet and will have no supporting effect on it. Under the action of gravity, the right side of the straight tube billet is prone to axial deviation from the upper mold 51 and the lower mold 52, which affects the forming quality of the tapered section 21b. Therefore, in order to achieve synchronization between the downward movement of the pressing and the downward movement of the support roller 83, as shown in FIG. Figure 18-19 As shown, a driving plate 9 is provided on the side wall of the lower mold 52, and a triangular plate 91 is provided on the outer surface of the driving plate 9. The side of the triangular plate 91 is a slope structure and can be abutted against the end of the crossbar 81. Figure 18-19 As shown, when the upper die 51 moves downward and its conical protrusion 5a contacts the surface of the straight tube blank, the bottom side of the inclined surface of the triangular plate 91 synchronously contacts the end of the crossbar 81. The upper die 51 continues to move downward, and the driving plate 9 drives the triangular plate 91 downward. The inclined surface of the triangular plate 91 simultaneously drives the crossbar 81 to the right (overcoming the force of the torsion spring). The hinged rod 84 deflects, causing the support roller 83 and the straight tube blank to move downward. This synchronizes the downward movement of the support roller 83 during pressing and the downward movement of the support roller 83, thereby alleviating the operational difficulty of manually driving the crossbar 81 and ensuring the forming quality of the inner tube 2. The driving plate 9 has a strip hole (not shown) to adjust the synchronization between the downward movement of the upper die 51 during pressing and the downward movement of the support roller 83. The specifications of the driving plate 9 and the triangular plate 91 can be changed to accommodate the forming of inner tubes 2 of different diameters.

[0065] The multiple tapered sections 21b on the inner tube 2 need to be pressed at equal (or unequal) spacings. However, the marking method manually made on the straight tube blank in advance may still cause deviations when corresponding to the tapered protrusions 5a of the upper die 51 and the lower die 52. Therefore, in order to facilitate the precise molding of the position of the tapered section 21b, as shown in FIG. Figure 21 As shown, a support rod 10 is provided on the outside of the tube support frame 8 in the direction of movement of the inner tube 2. A sleeve 11 is horizontally provided at the top of the support rod 10. A ruler rod 12 is inserted into the sleeve 11. The end of the ruler rod 12 is preferably also provided with a vertical plate 13. The ruler rod 12 has dimension lines engraved thereon. One end of the straight tube blank contacts the vertical plate 13 at the end of the ruler rod 12. The movement of the straight tube blank drives the ruler rod 12 to move. The dimension lines on the ruler rod 12 correspond to the readings at the end of the sleeve 11, thereby accurately visually monitoring the pressing and forming of the tapered section 21b of the inner tube 2, while also improving the efficiency of the continuous pressing operation of the tapered section 21b.

[0066] The straight tube billet needs to be pressed to form the tapered section 21b, which needs to be heated to the thermal deformation temperature. It can be pressed and formed after heating in a heating furnace. However, there will be a temperature drop during the transfer process after heating. In addition, multiple tapered sections 21b need to be pressed on the straight tube billet. During the later pressing process, the temperature drop is large, making it difficult to press smoothly and easily causing cracks and breakage in the pressed parts. Therefore, in order to facilitate pressing and forming at the thermal deformation temperature, as shown in FIG. Figure 22-23As shown, an assembly rod 14 is hinged on the transverse limit rod 71, and a heating gun 15 is axially slidably mounted on the assembly rod 14. The assembly rod 14 is preferably hinged on the side wall of the transverse limit rod 71. When not heated, the assembly rod 14 is in a vertical state and does not extend beyond the inner side of the transverse limit rod 71, so that the upper mold 51 will not contact or interfere with the assembly rod 14 when it moves downward. During heating before pressing, the heating gun 15 is preferably assembled on the assembly rod 14 by a binding member such as a clamp. The heating gun 15 is not fastened to the assembly rod 14. The heating gun 15 is preferably hung on the assembly rod 14 so that the heating gun 15 can move left and right on the assembly rod 14, so that the gun head of the heating gun 15 can be close to or away from the surface of the straight tube billet. Before heating begins, the gun head of the heating gun 15 can be kept away from the surface of the straight tube billet and then gradually approached to achieve slow heating and avoid the impact of excessive temperature rise on the internal structure. Since the assembly rod 14 is hinged, the assembly rod 14 can be rotated during the heating process, rotating the heating gun 15 to fully heat the circumference of the straight tube billet that is exposed outside the lower mold 52. As for the portion blocked by the lower mold 52, the straight tube billet is heated by rotating the straight tube billet (the thermal deformation temperature of the upper mold 51 and the lower mold 52 must be greater than the thermal deformation temperature of the straight tube billet). The present application adopts a local heating method of the heating gun 15, which can replace the long-term heating of the heating furnace, and the unheated portion can facilitate the rotation of the straight tube billet. The support roller 83 can preferably be made of metal and have a smooth surface to facilitate the rotation operation of the straight tube billet under the support of the support roller 83.

[0067] According to the above-mentioned integrated molding die, the present application also provides an integrated molding method for a nickel-made large-diameter continuous lotus-shaped heat exchanger, comprising the following steps: S1. Place the straight tube blank for forming the inner tube 2 on the supporting roller 83 of the tube body supporting frame 8.

[0068] S2. The straight tube blank is driven to move on the supporting roller 83 and its end is extended into the lower die 52 by a certain length. The pressing position is determined by pushing the ruler 12 through the end of the straight tube blank.

[0069] S3. The straight tube blank and the portion of the tapered protrusion 5 a exposed outside the lower die 52 are surface heated by the axial movement and vertical deflection of the heating gun 15 , while the straight tube blank is driven to rotate on the support roller 83 .

[0070] S4. After the surface of the straight tube billet is heated to the thermal deformation temperature, the hydraulic cylinder 4 moves downward, driving the upper die 51 to press the straight tube billet downward. The upper die 51 drives the triangular plate 91 to move downward, and the triangular plate 91 drives the cross bar 81 to move right and downward, so that the downward movement depth of the straight tube billet on the lower die 52 is synchronized with the downward movement depth on the support roller 83. The straight tube billet is squeezed by the conical protrusions 5a of the upper die 51 and the lower die 52, and the prototype of the tapered mouth section 21b is formed on its surface.

[0071] S5. Drive the upper die 51 downward multiple times while rotating the straight tube billet, forming the tapered section 21b on the straight tube billet's surface. For example, if the tapered section 21b is 10 mm deep, the circumferential pressing depth can be preferably 2-5 mm at each circumferential pressing. After achieving this depth along the circumference of the straight tube billet, the upper die 51 is pressed downwards to a depth of 10 mm (preferably, the inner surfaces of the upper die 51 and lower die 52 contact the outer circumference of the straight tube billet, i.e., the pressing depth reaches the set 10 mm), thereby gradually pressing the tapered section 21b. Before each increase in pressing depth, the heat gun 15 can be used to preheat the billet to compensate for temperature drops.

[0072] S6. After the single tapered section 21b is formed, the straight tube billet is driven to move on the supporting roller 83, driving the ruler 12 to move backward, and repeating steps S3-S5 to form the straight tube billet into an integral inner tube 2 with a lotus-shaped structure; S7. Insert the inner tube 2 into the outer tube 1, and weld the end of the inner tube 2 and the inner wall of the outer tube 1 to seal them, thereby forming the continuous lotus-shaped heat exchanger.

[0073] At present, small-diameter (such as within 50mm) pipes can be rolled into seamless pipes, while large-diameter pipes are usually difficult to roll into shape. Most of them are made by rolling a plate into a pipe body and then welding the sides into a large-diameter pipe body. When pressing the inner pipe, the present application adopts an integrated forming mold and gradually presses and forms it under a heated state, so that it can be suitable for the forming operation of large-diameter inner pipes, solving the problem of increased welds caused by multi-section welding. The large-diameter pipe body has a larger heat exchange area in the heat exchanger, so that the integrated forming mold and method disclosed in the present application can realize the processing and forming of large-diameter heat exchangers, so that the inner pipe can withstand the designed fluid pressure.

[0074] The above shows and describes the basic principles, main features and advantages of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of protection claimed by the present invention.

Claims

1. A nickel-made, large-diameter, continuous lotus-shaped heat exchanger comprising an outer tube and an inner tube, wherein a closed heat exchange chamber is formed between the outer and inner tubes, and an inlet and an outlet are sequentially provided on the upper and lower diagonal surfaces of the outer tube, communicating with the heat exchange chamber. The outer tube is a straight tube structure, characterized in that: The inner tube is a continuous lotus-shaped structure, which is composed of a plurality of continuous lotus-shaped short sections.

2. The continuous lotus-shaped heat exchanger according to claim 1, characterized in that: Each of the lotus-shaped short sections comprises a straight section and inwardly contracted tapered sections at both ends of the straight section, and adjacent lotus-shaped short sections are connected by the tapered sections.

3. The continuous lotus-shaped heat exchanger according to claim 2, characterized in that: Each of the cone sections is an arc structure and is in arc transition with the straight cylinder section, and the adjacent cone sections are connected with arc transition.

4. An integral molding die for a nickel-made large-caliber continuous lotus-shaped heat exchanger, characterized in that: include: The frame is composed of symmetrical vertical beams and a horizontal beam at the top; A driving member is provided below the crossbeam to realize vertical driving; The mold body includes an upper mold arranged below the driving member and a lower mold located on the ground below the upper mold. The upper mold and the lower mold are both semi-circular cylindrical structures, and conical protrusions are correspondingly arranged above and below the upper mold and the lower mold to fit the tapered mouth sections where adjacent lotus-shaped short sections are connected. The conical protrusions are V-shaped structures with arc transitions.

5. The one-piece molding die according to claim 4, characterized in that: A plurality of ribs are arranged at intervals along the axial direction on the back side of the upper mold and are connected to the driving component. A plurality of ribs are arranged on the back side of the lower mold and are fixed on the ground.

6. The one-piece molding die according to claim 5, characterized in that: Transverse limiting rods are provided on the left and right sides of the rib surface of the lower die for vertically limiting the downward movement of the upper die, and the top ends of the transverse limiting rods can penetrate into the adjacent ribs of the upper die.

7. The one-piece molding die according to claim 5, wherein: Axial limiting rods for axially limiting the downward movement of the upper mold are provided on both the left and right sides of the front and rear end surfaces of the lower mold.

8. The one-piece molding die according to claim 6 or 7, characterized in that: A tube support frame is provided on both sides of the lower die, and support rollers are provided on the support frame along the axial direction of the inner tube; The tube support frame is composed of a horizontal bar and a vertical bar. The support rollers are arranged at intervals on the horizontal bar. The vertical bar is a threaded telescopic sleeve structure, and the top end is hingedly connected to the horizontal bar. The vertical rod includes a sleeve section and a screw section, the top end of the sleeve section is hinged with a hinged rod, the hinged rod is hingedly connected to the cross rod, and a torsion spring is provided at the hinge point between the hinged rod and the sleeve section to drive the hinged rod to rotate toward the lower mold, and a vertical limit plate is provided on the side wall of the sleeve section to contact the side wall of the hinged rod; A driving plate is provided on the side wall of the lower mold, and a triangular plate is provided on the outer surface of the driving plate. The side of the triangular plate is a sloped structure and can be abutted against the end of the cross bar; A support rod is provided on the outside of the tube body support frame in the moving direction of the inner tube, a sleeve is horizontally provided on the top of the support rod, a ruler rod is passed through the sleeve, and dimension lines are engraved on the ruler rod.

9. The one-piece molding die according to claim 8, characterized in that: An assembly rod is hinged on the transverse limiting rod, and a heating gun is axially slidably assembled on the assembly rod.

10. A method for integrally forming a nickel-made large-diameter continuous lotus-shaped heat exchanger, characterized in that: The following steps are involved: S1. Place the straight tube blank for forming the inner tube on the supporting roller of the tube body support frame; S2, driving the straight tube billet to move on the supporting roller, and making its end extend into the lower die to a certain length; S3, surface heating the straight tube blank and the portion of the tapered protrusion exposed outside the lower die by axial movement and vertical deflection of the heating gun; S4. After the surface of the straight tube billet is heated to the thermal deformation temperature, the driving member moves downward, driving the upper die to press the straight tube billet downward. The straight tube billet is squeezed by the conical protrusions of the upper die and the lower die, forming a prototype of a tapered mouth section on its surface; S5, driving the upper die to move downward multiple times, and rotating the straight tube blank at the same time, so that the tapered section on the surface of the straight tube blank is formed; S6. After the single tapered section is formed, the straight tube billet is driven to move on the supporting rollers, and steps S3-S5 are repeated to form the straight tube billet into an integral inner tube with a lotus root-shaped structure; S7. Insert the inner tube into the outer tube, and weld the port of the inner tube and the inner wall of the outer tube to seal, thereby forming the continuous lotus-shaped heat exchanger.

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