Pipe end flaring method combining flaring, cleaning and cooling in multiple processes

Abstract

The application discloses a pipe end flaring forming method of flaring cleaning and cooling multi-process integration, and has the characteristics of designing a three-in-one needle, keeping the three-in-one needle coaxial with the processed pipe, oiling, flaring forming inner hole shaping, keeping the mutual position of the three-in-one needle and the processed pipe unchanged, the needle head cone body and the cone hole part forming a seal, the compressed gas being punched into the compressed gas channel, the airflow being punched out of the outer part through the jet hole along the flared forming inner hole wall of the processed pipe in the reverse direction to blow out the stains, and the three-in-one needle and the processed pipe being cooled at the same time. The method simplifies the process, reduces the labor time cost, and improves the production efficiency. The method solves the problems of sewage discharge, secondary corrosion in the pipe, and easy rusting of the pipe opening caused by traditional technologies such as water-based cleaning agent cleaning and solvent cleaning after flaring, has no VOC emission, is non-toxic and harmless, and is non-flammable and non-explosive. The method reduces product surface scratches, is safe in the operation process, and is reliable in product quality.

Description

Technical Field

[0001] This invention relates to refrigerator heat exchanger tube manufacturing technology, and in particular to a tube end flaring and forming method that integrates multiple processes such as flaring, cleaning, and cooling. Background Technology

[0002] During the manufacturing of refrigerator heat exchanger tubes, the ends need to be flared. During this flaring process, carbon deposits are generated due to the use of flaring fluid and temperature increases. Residual flaring oil also adheres to the inner wall of the tube, forming stains. If these stains are not cleaned properly, they will affect subsequent brazing processes, causing serious quality problems in the finished product.

[0003] For stains on the inner walls of small-diameter pipes, the existing cleaning methods mainly include the following:

[0004] One method involves solvent cleaning followed by drying. After flaring the opening, the container is placed in an organic solvent cleaning tank for cleaning, and then allowed to air dry. The disadvantage of this method is that the use of organic solvents is not only harmful to human health but also generates significant VOC emissions.

[0005] The second method involves water-based ultrasonic cleaning → water washing (repeated water washing) → passivation → water washing → drying. The disadvantages of this method are: a long process route, low efficiency, and the generation of a large amount of wastewater, increasing environmental pressure; high production costs and energy consumption, hindering energy conservation and emission reduction; a potential quality hazard due to the possibility of the inner wall of the pipe not being completely dried, easily causing ice blockage in the refrigerator; and the possibility of rusting during drying.

[0006] In addition, domestic heat exchanger tube manufacturers currently carry out tube end flaring processes in multiple steps, from oiling to flaring to various cleaning methods. The whole process is complicated, involving on-site assembly line logistics transfer, repeated process inspections, etc., resulting in high labor and time costs and low production efficiency. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned problems and provide a pipe end flaring and forming method that integrates flaring, cleaning, and cooling into a single process. Through the design of the three-in-one needle and the analysis of its relationship with the pipe being processed, the method utilizes compressed gas to reverse high pressure to flush away dirt from the inner wall of the pipe during the flaring and forming process. This method features continuous or simultaneous multi-process operation, reduced transfer of semi-finished products between processes, lower labor and time costs, significantly improved finished product manufacturing efficiency, stable and reliable quality, and no VOC emissions.

[0008] The above-mentioned technical problems of the present invention are mainly solved by the following technical solution: a method for forming a pipe end flaring and cleaning process that integrates multiple steps, characterized by comprising the following:

[0009] A. Design a three-in-one needle, the three-in-one needle includes a needle bar, the front end of the needle bar has a needle tip with a diameter larger than the diameter of the needle bar, the needle tip has a conical part; the length of the needle bar is greater than the length of the inner hole of the tube being processed; a compressed gas channel is provided along the axial direction of the three-in-one needle, and an air jet hole is provided at the bottom end of the compressed gas channel.

[0010] B. Keep the three-in-one needle coaxial with the tube being processed.

[0011] C. Apply oil to the opening of the pipe being processed.

[0012] D. Move the three-in-one needle or the tube being processed, and use the needle to squeeze the tube to shape the flared inner hole in the inner hole of the tube, while simultaneously forming a tapered hole.

[0013] E. Keep the relative positions of the three-in-one needle and the tube being processed unchanged. At this time, the conical part of the needle tip and the conical hole part form a seal, and the flared inner hole and the outer diameter of the needle bar form a clean space.

[0014] F. Compressed gas is injected into the compressed gas channel, and the airflow is sprayed into the clean space through the jet hole, and then blown out in the opposite direction along the inner wall of the flared forming of the processing tube, blowing away the stains adhering to the inner wall of the flared forming of the processing tube; at the same time, the three-in-one needle and the processed tube are cooled.

[0015] G. Turn off the compressed gas, move the three-in-one needle or the workpiece tube, and unload the workpiece tube.

[0016] In the aforementioned pipe end flaring and forming method that integrates flaring, cleaning, and cooling processes, preferably, the three-in-one needle is made of tool steel, and its needle head includes a conical part plus a cylindrical part with a diameter larger than the needle bar that serves as a sizing element, with the air jet located at the bottom end of the needle bar.

[0017] In the aforementioned tube end flaring and forming method that integrates flaring, cleaning, and cooling processes, preferably, the surface of the three-in-one needle is provided with a ceramic coating and is smooth, with a surface hardness ≥ HV3500.

[0018] In the aforementioned pipe end flaring forming method that integrates flaring, cleaning, and cooling processes, preferably, the airflow injected from the jet hole into the clean space is turbulent or spiral airflow.

[0019] In the aforementioned pipe end flaring and forming method that integrates flaring, cleaning, and cooling processes, preferably, the compressed gas injected into the compressed gas channel is a pulsed gas flow.

[0020] In the aforementioned pipe end flaring and forming method that integrates flaring, cleaning, and cooling processes, preferably, the cross-sectional area of ​​the compressed gas channel is larger than the cross-sectional area of ​​the clean space to maintain an effective pressure difference.

[0021] In the aforementioned pipe end flaring and forming method that integrates flaring, cleaning, and cooling processes, preferably, the jet holes are symmetrically or evenly distributed around the wall of the compressed gas channel, and the jet holes form an acute angle with one diameter of the circle of the compressed gas channel.

[0022] In the aforementioned pipe end flaring and forming method that integrates flaring, cleaning, and cooling processes, preferably, the three-in-one needle also includes a needle seat, the shape of which is larger than the outer diameter of the needle rod, wherein the portion of the needle rod that is longer than the inner hole of the flaring and forming of the pipe being processed and the end face of the needle seat form a sludge discharge area.

[0023] In the aforementioned pipe end flaring and forming method that integrates flaring, cleaning, and cooling processes, preferably, the compressed gas injected into the compressed gas channel is dry cold air with a humidity range of 1% to 5% and a temperature ≤25℃.

[0024] This technical solution, based on the structural characteristics of refrigerator heat exchange tubes (condenser tubes), designs a three-in-one needle, completely negating the traditional multi-process, multi-site, multi-workshop operation method involving oiling, flaring, cleaning, drying, and cooling. The three-in-one needle uses a needle shaft as its base, with an axially arranged blind-hole-shaped compressed gas channel. An air jet is located at the bottom of the compressed gas channel, leading to the outside of the needle shaft. The front end of the needle shaft is designed with a needle tip with a diameter larger than the needle shaft, serving as a flaring die. The flaring of the processed tube to form the inner hole is completed by the flaring die. Since the flared end of the processed tube will form a tapered hole with the original tube diameter, this solution utilizes this tapered hole by adding a tapered section to the needle tip of the three-in-one needle. During the shaping of the flared inner hole, the tapered section and the tapered hole maintain a mutually sealing relationship, creating a space between the outer diameter of the needle shaft and the flared inner hole that requires cleaning.

[0025] Thus, as long as the relative positions of the three-in-one needle and the workpiece remain unchanged, the stains on the inner wall of the flared forming hole can be blown and cleaned by injecting compressed gas. At the same time, both the three-in-one needle and the workpiece can be cooled, especially reducing the surface temperature of the three-in-one needle and improving its service life.

[0026] Furthermore, regarding the flaring tip of the three-in-one needle: The three-in-one needle is made of tool steel. For soft workpieces such as copper and aluminum, the tip can be made with a diameter larger than the shank. In this design, a ceramic coating is preferred on the tip surface. This easily produces a smooth surface, and its surface hardness meets design requirements. This high-hardness, smooth surface is less likely to scratch the workpiece surface during flaring, has a low shrinkage rate, stable sizing standards, and results in a smoother, finer surface, thus greatly improving corrosion resistance.

[0027] Furthermore, regarding the cleaning airflow intensity and cleaning effect: The design of the jet holes in this solution can achieve the air knife purging effect of turbulent or spiral airflow. Turbulence, also known as turbulent flow, occurs when the flow velocity increases significantly, making streamlines indistinguishable and creating numerous small vortices in the flow field. Adjacent flow layers not only slide but also mix, forming turbulence. This disordered, diffusing airflow thoroughly cleans various types of stains adhering to the flared inner hole. Spiral airflow, on the other hand, is an airflow with specific rotational characteristics. It moves in a spiral shape, possessing a certain directionality and rotational speed. This airflow form has excellent shearing force on the surface of the cylindrical inner wall tube, similar to polishing.

[0028] In this design, the cross-sectional area of ​​the compressed gas channel must be larger than that of the clean space to maintain an effective pressure differential. Therefore, when the diameter of the pipe being processed is smaller than a certain value, the implementation of this design becomes more difficult.

[0029] Furthermore, regarding operation and application: The highly rigid three-in-one needle tip's tapered section mates with the inner diameter of the original tube hole during the initial flaring process, instantly forming a natural centering and positioning with the tube. While maintaining the three-in-one needle and the tube coaxial, there's no need to consider offset factors. The operation is simple and intuitive, enabling automated processing. During the flaring and shaping of the inner hole, maintaining appropriate pressure on the three-in-one needle is sufficient to meet sealing requirements, preventing contaminated gas from entering the original tube hole.

[0030] Furthermore, this solution also incorporates applications such as dry cold air and pulsed airflow based on product characteristics, offering users a wide range of choices. The aim is to ensure that the inner hole of the flaring forming process is cleaned in one go, keeping the product surface dry, preventing rust, protecting the three-in-one needle and its supporting facilities, and extending the service life of the equipment.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: it completely changes the problem that traditional pipe end flaring requires multiple processes, simplifies the process, reduces labor and time costs, and improves production efficiency; it solves the problems of sewage discharge, secondary corrosion inside the pipe, and easy rusting of the pipe end caused by traditional technologies such as water-based cleaning agents and solvent cleaning after flaring; it has no VOC emissions, is non-toxic and harmless, and is not flammable or explosive; it reduces scratches on the product surface, ensures safe operation, and guarantees reliable product quality. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an operational state structure according to the present invention.

[0033] Figure 2 yes Figure 1 A magnified schematic diagram of the structure at point M in the middle.

[0034] Figure 3A schematic diagram of a three-in-one needle structure according to the present invention.

[0035] Figure 4 This is a schematic diagram of the flared end structure of a processed tube according to the present invention.

[0036] In the diagram: 1-Three-in-one needle, 101-Needle seat, 102-Needle bar, 103-Conical part, 104-Compressed gas channel, 105-Air jet hole, 2-Processing tube, 201-Flanged inner hole, 202-Conical hole, 203-Original tube hole, 3-Stain, 4-Clean space.

[0037] A-Discharge Zone. Detailed Implementation

[0038] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0039] This embodiment presents a pipe end flaring and forming method that integrates multiple processes such as flaring, cleaning, and cooling. It is a pipe end flaring manufacturing method that integrates multiple processes such as oiling, flaring, shaping, dry cleaning, and drying using a three-in-one needle 1.

[0040] Taking the flared end of the refrigerator steel pipe as processing pipe 2, the structure of its flared part after shaping is as follows: Figure 4 As shown, the process includes the original tube hole 203 and the flared inner hole 201, which serves as the brazing mating part for the next process. A tapered hole 202 is formed between the original tube hole 203 and the flared inner hole 201. Due to the characteristics of the flaring process, a small amount of oil stains will remain on the wall of the flared inner hole 201 of the processed tube 2 (carbon deposits will appear at high temperatures, which will then form stains 3). As the flaring process progresses, the oil stains will gradually decrease until they disappear.

[0041] This embodiment also includes an air compressor, an air dryer, a cooler, a clamping device for the processing tube 2, a three-in-one pin 1 fixing and pushing mechanism, and an automated control system, etc., all of which are implemented using conventional technical means and will not be described in detail here.

[0042] This embodiment includes the following:

[0043] A. Design a three-in-one needle 1, which is made of tool steel, such as... Figure 3 As shown, the three-in-one needle 1 includes a needle bar 102, and a needle tip 102 with a diameter larger than that of the needle bar at its front end. The needle tip 102 includes a conical portion 103 and a cylindrical portion with a diameter larger than that of the needle bar 102 for sizing. The length of the needle bar 102 is greater than the length of the flared inner hole 201 of the workpiece tube 2. A compressed gas channel 104 is provided along the central axis of the three-in-one needle 1, and an air jet hole 105 is provided at the bottom end of the compressed gas channel 104, which is also located at the bottom end of the needle bar 102.

[0044] The needle tip 102 of the three-in-one needle 1 has a ceramic coating 6 on its surface. The surface of the ceramic coating 6 is smooth and the surface hardness of the needle tip 102 is ≥HV3500.

[0045] The three-in-one needle 1 also includes a needle seat 101. The outer diameter of the needle seat 101 is larger than the outer diameter of the needle bar 102. The length of the needle bar 102 that is larger than the flared inner hole 201 of the processed tube 2 and the end face of the needle seat 101 form a sewage discharge area A. The sewage discharge area A is sealed and collected to the sewage collection device.

[0046] The following conditions must be met: the cross-sectional area of ​​the compressed gas passage 104 is greater than the cross-sectional area of ​​the clean space 4 to maintain an effective pressure difference. The clean space 4 is a small space with a single-sided gap formed by the flared inner hole 201 and the outer diameter of the needle rod 102.

[0047] B. Keep the three-in-one needle 1 and the tube being processed 2 coaxial.

[0048] C. Apply flaring oil to the opening of the pipe being processed.

[0049] D. Move the three-in-one needle 1, and use the needle tip to press the workpiece tube 2 to shape the flared inner hole 201 in the inner bore of the workpiece tube 2, while simultaneously forming the tapered hole 202, as shown. Figure 1 , Figure 2 As shown.

[0050] E. Keep the relative positions of the three-in-one needle 1 and the processed tube 2 unchanged. At this time, the needle cone part 103 and the cone hole part 202 form a sealed fit, and the flared inner hole 201 and the outer diameter of the needle bar 102 form a clean space 4.

[0051] The airflow injected from the jet orifice 105 into the clean space 4 is turbulent or spiral airflow. The turbulent effect is generated by multiple jet orifices 105, which are laterally arranged at the bottom of the injection orifice 104, and are evenly distributed around the orifice wall. The spiral airflow effect is achieved by the jet orifices 105 being symmetrically or evenly distributed around the orifice wall of the compressed gas channel 104, with the jet orifices 105 forming an acute angle with one diameter of the circle of the compressed gas channel 104.

[0052] The compressed gas introduced into the compressed gas channel 104 is a pulsed airflow. The compressed gas introduced into the compressed gas channel 104 is dry, cold air with a humidity range of 1% to 5% and a temperature of ≤25℃, which can be adjusted appropriately according to the working environment and season.

[0053] F. After compressed gas is injected into the compressed gas channel 104, the airflow is sprayed into the cleaning space 4 through the jet hole 105, and then blows out in the opposite direction along the inner wall of the flared end forming 201 of the processing tube, blowing away the dirt 3 adhering to the inner wall of the flared end forming 201 of the processing tube. At the same time, the three-in-one needle 1 and the processed tube 2 are also cooled. The dry air keeps the blown surface dry and prevents rust spots.

[0054] G. Turn off the compressed gas, remove the three-in-one needle 1, and unload the processed tube 2.

[0055] Note: For the steel pipe for refrigerators in this embodiment, a cleaning space 4 is left between the flared inner hole 201 of the processed pipe 2 and the outer diameter of the three-in-one needle 1 rod 102 that cooperates with it. The cleaning space 4 can be 0.1 to 0.3 mm on one side.

[0056] The above embodiments are illustrative of the present invention and not intended to limit it. For example, when the three-in-one needle 1 and the workpiece tube move relative to each other, in some cases the three-in-one needle 1 may be fixed while the workpiece tube moves, or the workpiece and mold may move relative to each other, etc. Although the present invention has been described in conjunction with preferred embodiments, it should be understood that the present invention is not limited to the preferred embodiments. Those skilled in the art can make various equivalent modifications and substitutions to the technical solutions of the present invention based on the teachings of the present invention. Therefore, the scope of the present invention should be defined by the claims, and all such equivalent modifications and substitutions fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for forming pipe ends by integrating flaring, cleaning, and cooling into a single process, characterized in that, Includes the following: A. Design a three-in-one needle (1), the three-in-one needle includes a needle bar (102), the front end of the needle bar has a needle tip with a diameter greater than the diameter of the needle bar, and the needle tip has a conical part (103); the length of the needle bar is greater than the length of the flared inner hole (201) of the workpiece tube (2); a compressed gas channel (104) is provided along the axial direction of the three-in-one needle, and an air jet hole (105) is provided at the bottom end of the compressed gas channel; the three-in-one needle (1) also includes a needle seat (101), the shape of the needle seat (101) is greater than the outer diameter of the needle bar (102), wherein the portion of the needle bar (102) that is greater than the length of the flared inner hole (201) of the workpiece tube (2) and the end face of the needle seat form a sludge discharge area (A); B. Keep the three-in-one needle (1) and the tube being processed (2) coaxial; C. Apply oil to the opening of the pipe (2) being processed; D. Move the three-in-one needle (1) or the tube to be processed (2), and squeeze the tube to be processed (2) by the needle to shape the flared inner hole (201) in the inner hole of the tube to be processed (2), and at the same time form the tapered hole (202). E. Keep the relative positions of the three-in-one needle (1) and the tube being processed (2) unchanged. At this time, the cone part (103) of the needle tip and the cone hole part (202) form a seal, and the flared inner hole (201) and the outer diameter of the needle bar (102) form a clean space (4). F. Compressed gas is injected into the compressed gas channel, and the airflow is sprayed into the clean space (4) through the jet hole, and then blown out in the opposite direction along the flared inner hole (201) wall of the workpiece tube (2), blowing away the dirt (3) adhering to the flared inner hole (201) wall of the workpiece tube (2); at the same time, the three-in-one needle (1) and the workpiece tube (2) are cooled. G. Turn off the compressed gas, move the three-in-one needle (1) or the processed tube (2), and unload the processed tube (2).

2. The pipe end flaring and forming method integrating flaring, cleaning, and cooling processes according to claim 1, characterized in that, The three-in-one needle (1) is made of tool steel, and its needle head includes a conical part (103) plus a cylindrical part with a diameter greater than that of the needle bar (102) that serves as a sizing part, and an air jet hole (105) is located at the bottom of the needle bar.

3. The pipe end flaring and forming method integrating flaring, cleaning, and cooling processes according to claim 1 or 2, characterized in that, The needle tip of the three-in-one needle (1) has a ceramic coating (6) and a smooth surface, and the surface hardness of the needle tip is ≥HV3500.

4. The pipe end flaring and forming method integrating flaring, cleaning, and cooling processes according to claim 1, characterized in that, The airflow injected from the jet hole (105) into the clean space (4) is turbulent or spiral.

5. The pipe end flaring and forming method integrating flaring, cleaning, and cooling processes according to claim 1 or 4, characterized in that, The compressed gas injected into the compressed gas channel (104) is a pulsed gas flow.

6. The pipe end flaring and forming method integrating flaring, cleaning, and cooling processes according to claim 1, characterized in that, The cross-sectional area of ​​the compressed gas channel (104) is larger than the cross-sectional area of ​​the clean space (4), thus maintaining an effective pressure difference.

7. The pipe end flaring and forming method integrating flaring, cleaning, and cooling processes according to claim 5, characterized in that, The jet holes (105) are symmetrically or evenly distributed around the wall of the compressed gas channel (104), and the jet holes form an acute angle with one of the diameters of the circle of the compressed gas channel.

8. The pipe end flaring and forming method integrating flaring, cleaning, and cooling processes according to claim 1 or 4, characterized in that, The compressed gas introduced into the compressed gas channel (104) is dry cold air with a humidity range of 1% to 5% and a temperature of ≤25℃.

Images