Pipe end flaring forming method integrating multiple procedures of flaring, cleaning and cooling

Abstract

The invention discloses a pipe end flaring forming method integrating multiple procedures of flaring, cleaning and cooling, which is characterized by comprising the following steps: designing a trinity needle, keeping the trinity needle and a processed pipe in a coaxial state, oiling, forming a flaring forming inner hole, keeping the mutual positions of the trinity needle and the processed pipe unchanged, and sealing a needle head cone part and a taper hole part. Compressed air is pumped into the compressed air channel, air flow reversely rushes out along the inner hole wall of the flaring forming of the machining pipe through the air injection hole to blow out stains, and meanwhile the trinity needle and the machined pipe are both cooled. Procedures are simplified, labor and time cost is reduced, and production efficiency is improved; the problems of sewage discharge, secondary corrosion in the pipe, easy rusting of the pipe orifice and the like caused by the traditional technologies of cleaning with a water-based cleaning agent, cleaning with a solvent and the like after flaring are solved, and no VOC (Volatile Organic Compound) discharge, no toxicity, no harm, no flammable and combustible properties are realized; product surface scratches are reduced, the operation process is safe, and the product quality is reliable.

Description

Technical Field

[0001] The invention relates to a manufacturing technology for a refrigerator heat exchange tube, in particular to a tube end expanding and forming method which integrates multiple processes of expanding, cleaning and cooling. Background Art

[0002] The ends of refrigerator heat exchange tubes need to be expanded during production. During the process of expanding, carbides will be produced due to the use of expanding fluid and temperature rise, and residual expanding oil will also adhere to the inner wall of the tube to form stains. If these stains are not cleaned up, they will affect the brazing of the subsequent process and cause serious quality problems for the finished product.

[0003] For the stains on the inner wall of such a small diameter tube, the existing cleaning methods are mainly the following:

[0004] The first method is solvent cleaning → drying. After the expansion, the pipe is placed in an organic solvent cleaning tank for cleaning, and then dried naturally. The disadvantage of this method is that since organic solvents are used for cleaning, it is not only harmful to the human body, but also produces a large amount of VOC emissions.

[0005] The second is water-based ultrasonic cleaning → water washing (repeated water washing) → passivation → water washing → drying. The disadvantages of this method are: long process route, low efficiency, also produces a lot of wastewater, increasing environmental pressure; high production cost, high energy consumption, not conducive to energy saving and emission reduction; there is a quality risk that the water on the inner wall of the pipe cannot be dried, which is easy to cause ice blockage in the refrigerator; in addition, it is easy to cause rust during drying.

[0006] In addition, at present, domestic heat exchange tube manufacturers basically carry out the tube end expansion process in multiple steps, from oiling → expansion → various cleaning methods. The whole process is cumbersome, such as on-site assembly line logistics transfer, repeated process inspection, etc., the manpower and time costs are high, and the production efficiency is low. Summary of the invention

[0007] The purpose of the present invention is to solve the above-mentioned problems and to provide a tube end flaring forming method which integrates multiple processes of flaring, cleaning and cooling. Through the design of a three-in-one needle and the analysis of the characteristics of its relationship with the processed tube, during the flaring forming process, compressed gas is used to reversely high-pressure wash the stains on the inner wall of the tube. The method has the characteristics of carrying out multiple processes continuously or simultaneously, reducing the transfer of semi-finished products between processes, reducing manpower and time costs, greatly improving the manufacturing efficiency of finished products, and having stable and reliable quality and no VOC emissions.

[0008] The above technical problem of the present invention is mainly solved by the following technical solution: a pipe end flaring forming method integrating flaring, cleaning and cooling processes, characterized in that it includes the following contents:

[0009] A. Design a three-in-one needle, which includes a needle rod, a needle head with a diameter larger than that of the needle rod at the front end of the needle rod, and a cone portion; the length of the needle rod is larger than the length of the inner hole of the expanded tube being processed; a compressed gas channel is provided along the axial direction of the three-in-one needle, and a jet hole is provided at the bottom end of the compressed gas channel.

[0010] B. Keep the trinity needle and the processed tube coaxial.

[0011] C. Oil the pipe ends to be processed.

[0012] D. Move the three-in-one needle or the processed tube, and squeeze the processed tube with the needle to shape the expanded inner hole in the inner hole of the processed tube and form a tapered hole at the same time.

[0013] E. Keep the relative position of the three-in-one needle and the processed tube unchanged. At this time, the cone part of the needle head and the cone hole part form a seal, and the expanded inner hole and the outer diameter of the needle rod form a clean space.

[0014] F. Inject compressed gas into the compressed gas channel, and the airflow is ejected into the clean space through the jet hole, and rushes out in the opposite direction along the inner hole wall of the expanded molding of the processed tube, and the stains adhering to the inner hole wall of the expanded molding of the processed tube are blown out; at the same time, the three-in-one needle and the processed tube are cooled.

[0015] G. Turn off the compressed gas, move the trinity needle or the processed tube, and unload the processed tube.

[0016] In the aforementioned tube end flaring forming method integrating flaring, cleaning and cooling multiple steps, preferably, the three-in-one needle is made of tool steel, and its needle head includes a conical portion and a cylindrical portion with a diameter larger than the needle rod and serving as a sizing device, and the air jet hole is located at the bottom end of the needle rod.

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

[0018] In the aforementioned tube end expanding and forming method integrating the multiple steps of expanding, cleaning and cooling, preferably, the airflow sprayed from the air jet hole into the clean space is a turbulent or spiral airflow.

[0019] In the aforementioned tube end expanding and forming method integrating the multiple steps of expanding, cleaning and cooling, it is preferred that the compressed gas injected into the compressed gas channel is a pulsed gas flow.

[0020] In the aforementioned tube end expanding and forming method integrating the multiple steps of expanding, cleaning and cooling, 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 tube end expanding forming method integrating the multiple steps of expanding, cleaning and cooling, preferably, the jet holes are symmetrically or evenly distributed around the hole wall of the compressed gas channel, and the jet holes form an acute angle with a diameter of the circle of the compressed gas channel where they are located.

[0022] In the aforementioned tube end expansion and forming method integrating the expansion, cleaning and cooling steps, preferably, the three-in-one needle also includes a needle seat, the outer shape of the needle seat is larger than the outer diameter of the needle rod, wherein the needle rod is larger than the inner hole length of the expanded tube being processed and the end face of the needle seat to form a sewage discharge area.

[0023] In the aforementioned tube end expanding and forming method integrating the multiple steps of expanding, cleaning and cooling, 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°C.

[0024] This technical solution is designed according to the structural characteristics of refrigerator heat exchange tubes (condenser tubes), which completely negates the traditional multi-process, multi-site and multi-workshop operation methods such as oiling → expansion → cleaning → drying → cooling. The three-in-one needle uses the needle rod as the base, and is axially provided with a blind hole-shaped compressed gas channel. The bottom of the compressed gas channel is provided with an air jet hole, and the air jet hole leads to the outside of the needle rod. The needle head with a diameter larger than the needle rod at the front end of the needle rod is used as an expansion die, and the expansion forming inner hole of the processed tube is completed by the expansion die. Since the end of the processed tube will form a tapered hole part with the original tube diameter after expansion, this solution uses the tapered hole part to set a cone part on the needle head of the three-in-one needle. When the expansion forming inner hole is finalized, the cone part and the tapered hole part maintain a mutually matched sealing state relationship, and a space that needs to be cleaned is formed between the outer diameter of the needle rod and the expansion forming inner hole.

[0025] At this point, as long as the relative position of the three-in-one needle and the processed tube remains unchanged, the stains on the inner hole wall of the expansion molding can be blown and cleaned by injecting compressed gas, and at the same time, the three-in-one needle and the processed tube can be cooled, especially reducing the surface temperature of the three-in-one needle and increasing its service life.

[0026] Further, regarding the expanded needle of the trinity needle: the trinity needle is made of tool steel. For soft processed tubes, such as copper, aluminum, etc., the needle head can be directly made larger in diameter than the needle rod. In this scheme, a ceramic coating is preferably provided on the needle head surface, which is easy to obtain a smooth surface, and its surface hardness can meet the design requirements. Moreover, this high-hardness smooth surface is not easy to scratch the surface of the processed tube during expansion, has a small shrinkage rate, and a stable sizing standard, and makes the surface of the processed tube smoother and more delicate, thereby greatly improving the anti-corrosion effect.

[0027] Furthermore, regarding the intensity and effect of the cleaning airflow: the design of the jet hole in this scheme can obtain the air knife blowing effect of turbulent or spiral airflow. Turbulent flow is turbulent flow. When the flow rate increases to a large value, the streamlines are no longer clearly discernible, and many small vortices will form in the flow field. There is not only sliding but also mixing between adjacent flow layers, forming turbulence. This disordered and diffusive airflow can fully clean various stains adhering to the inner hole of the expanded molding. Spiral airflow is an airflow with specific rotation characteristics. It moves in a spiral form and has a certain directionality and rotation speed. This airflow form has better shear force on the surface of the cylindrical inner wall tube, just like polishing.

[0028] In this scheme, the cross-sectional area of ​​the compressed gas channel should be larger than the cross-sectional area of ​​the clean space to maintain an effective pressure difference. Therefore, when the diameter of the processed pipe is smaller than a certain value, the implementation difficulty of this scheme will also increase.

[0029] Furthermore, regarding the operation and application: the needle cone at the front end of the three-in-one needle with excellent rigidity of this solution will match the inner diameter of the original tube hole of the processed tube at the beginning of the expansion, and will instantly form a natural centering and positioning with the tapered hole of the processed tube. While keeping the three-in-one needle and the processed tube coaxial, there is no need to consider the factor of partial expansion. The action is simple and goes with the flow, and automatic operation can be achieved. When the inner hole of the expansion forming is finalized, as long as the appropriate pressure of the three-in-one needle is maintained, the sealing requirements can be met to prevent the gas containing stains from entering the original tube hole.

[0030] Furthermore, this solution also designs applications such as dry cold air and pulse airflow based on product characteristics, which allows users to have a wide range of choices. The purpose is to ensure that the inner hole of the expansion molding is cleaned at one time, keep the product surface dry, avoid rust, protect the three-in-one needle and its supporting facilities, and extend the service life of the equipment.

[0031] Compared with the prior art, the beneficial effects of the present invention are: completely changing the problem that traditional pipe end expansion requires multiple processes to complete, simplifying the process, reducing manpower and time costs, and improving production efficiency; solving the problems of sewage discharge, secondary corrosion in the pipe, easy rusting of the pipe mouth, etc. caused by traditional technologies such as cleaning with water-based cleaning agents and solvents after expansion, no VOC emissions, non-toxic and harmless, non-flammable and explosive; reducing product surface scratches, safe operation process, and reliable product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of an operating state structure of the present invention.

[0033] Figure 2 yes Figure 1 Schematic diagram of the local enlarged structure at M in the middle.

[0034] Figure 3A schematic diagram of a trinity needle structure of the present invention.

[0035] Figure 4 The present invention is a schematic diagram of the structure of the expanded end portion of a processed pipe.

[0036] In the figure: 1-trinity needle, 101-needle seat, 102-needle rod, 103-cone part, 104-compressed gas channel, 105-jet hole, 2-processing tube, 201-expanded inner hole, 202-cone hole part, 203-original tube hole, 3-stain, 4-clean space.

[0037] A-Drainage area. DETAILED DESCRIPTION

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

[0039] The present embodiment is a tube end flaring forming method that integrates multiple steps of flaring, cleaning and cooling. It is a tube end flaring manufacturing method that integrates multiple steps such as oiling → flaring → shaping → dry cleaning → drying by a three-in-one needle 1.

[0040] The end of the refrigerator steel pipe is expanded as the processing pipe 2, and the structure of the expanded part after shaping is as follows Figure 4 As shown, it includes the original tube hole 203, the expanded inner hole 201 as the brazing matching part of the next process, and the tapered hole 202 is formed between the original tube hole 203 and the expanded inner hole 201. According to the characteristics of the expansion process, a small amount of oil stains will be left on the wall of the expanded inner hole 201 of the processed tube 2 (carbon deposits will appear at high temperature, and then stains 3 will be formed). As the expansion progresses inward, the oil stains will gradually decrease until there is no oil stains.

[0041] In this embodiment, it also includes an air compressor, an air dryer, a cooler, a processing tube 2 clamping device, a three-in-one needle 1 fixing and pushing mechanism, and an automatic control system, etc., all of which are implemented according to conventional technical means and will not be described in detail here.

[0042] This embodiment includes the following contents:

[0043] A. Design the trinity needle 1, which is made of tool steel, such as Figure 3 As shown, the trinity needle 1 comprises a needle rod 102, the front end of which has a needle head 102 with a diameter greater than that of the needle rod, and the needle head 102 comprises a cone portion 103 plus a cylindrical portion with a diameter greater than that of the needle rod 102 and having a sizing function. The length of the needle rod 102 is greater than the length of the expanded inner hole 201 of the processed tube 2. A compressed gas channel 104 is provided along the central axis of the trinity needle 1, and an injection hole 105 is provided at the bottom end of the compressed gas channel 104, and the injection hole 105 is also located at the bottom end of the needle rod 102.

[0044] The surface of the needle head 102 of the trinity needle 1 is provided with a ceramic coating 6 , the surface of the ceramic coating 6 is a smooth surface, and the surface hardness of the needle head 102 is ≥ HV3500.

[0045] The trinity needle 1 also includes a needle seat 101, whose outer shape (outer diameter) is larger than the outer diameter of the needle rod 102, wherein the needle rod 102 is larger than the length of the expanded inner hole 201 of the processed tube 2 and the end face of the needle seat 101 to form a sewage discharge area A, and the sewage discharge area A is sealed and collected to the sewage collecting device.

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

[0047] B. Keep the trinity needle 1 and the processed tube 2 coaxial.

[0048] C. Apply expansion oil to the pipe mouth being processed.

[0049] D. Move the three-in-one needle 1, and squeeze the processed tube 2 by the needle head to shape the expanded inner hole 201 in the inner hole of the processed tube 2, and at the same time form the tapered hole part 202, such as Figure 1 , Figure 2 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 tapered hole part 202 form a sealing fit, and the expanded inner hole 201 and the outer diameter of the needle rod 102 are the clean space 4.

[0051] The airflow injected from the air jet hole 105 to the clean space 4 is turbulent or spiral airflow, wherein the turbulent effect is generated by the multiple air jet holes 105 disposed laterally at the bottom of the injection hole 104 and evenly distributed around the injection hole wall. The spiral airflow effect is obtained by the air jet holes 105 being symmetrically or evenly distributed around the hole wall of the compressed gas channel 104, and the air jet holes 105 and a diameter of the circle of the compressed gas channel 104 are at an acute angle.

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

[0053] F. After the compressed gas is injected into the compressed gas channel 104, the airflow is ejected into the clean space 4 through the air jet hole 105, and rushes out in the opposite direction along the inner hole wall of the processing tube expansion molding 201, and the stains 3 adhering to the inner hole wall of the processing tube expansion molding 201 are blown out, and at the same time, the three-in-one needle 1 and the processed tube 2 are also cooled. The dry air keeps the surface being blown dry to avoid rust spots.

[0054] G. Turn off the compressed gas, remove the trinity needle 1, and unload the processed tube 2.

[0055] Note: For the steel pipe pipeline for refrigerator in this embodiment, a clean space 4 is left between the expanded inner hole 201 of the processed tube 2 and the outer diameter of the needle rod 102 of the three-in-one needle 1 matched therewith, and the clean space 4 can be left with 0.1-0.3mm on one side.

[0056] The above embodiments are explanations of the present invention, not limitations of the present invention. For example, when the trinity needle 1 and the processed tube move relative to each other, the trinity needle 1 is fixed and the processed tube moves in some cases, or the workpiece and the mold move relative to each other, etc. Although the present invention is described in conjunction with the 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 limited by the claims, and all those equivalent modifications and substitutions belong to the protection scope of the technical solutions of the present invention.

Claims

1. A pipe end expansion forming method integrating expansion, cleaning and cooling processes, characterized in that: Includes the following: A. Design a three-in-one needle (1), the three-in-one needle comprising a needle rod (102), the front end of the needle rod having a needle head with a diameter greater than the diameter of the needle rod, the needle head having a cone portion (103); the length of the needle rod is greater than the length of the expanded inner hole (201) of the processed tube (2); a compressed gas channel (104) is provided along the axial direction of the three-in-one needle, and a gas injection hole (105) is provided at the bottom end of the compressed gas channel; B. Keep the trinity needle and the processed tube coaxial; C. Oil the mouth of the processed pipe; D. Move the three-in-one needle or the processed tube, and squeeze the processed tube (2) with the needle to shape the expanded inner hole in the inner hole of the processed tube, and at the same time form a tapered hole portion (202); E. Keep the relative position of the three-in-one needle and the processed tube unchanged. At this time, the cone part of the needle head and the cone hole part form a seal, and the expanded inner hole and the outer diameter of the needle rod form a clean space (4); F. The compressed gas is injected into the compressed gas channel, and the gas flow is ejected into the clean space through the gas jet hole, and then rushed out in the opposite direction along the inner hole wall of the expanded and formed processing tube, and the stains (3) adhering to the inner hole wall of the expanded and formed processing tube are blown out; at the same time, the three-in-one needle and the processed tube are cooled; G. Turn off the compressed gas, move the trinity needle or the processed tube, and unload the processed tube.

2. The pipe end expanding and forming method with multiple steps of expanding, cleaning and cooling in one according to claim 1 is characterized in that: The trinity needle (1) is made of tool steel, and its needle head comprises a cone portion (103) and a cylindrical portion having a diameter greater than that of the needle rod (102) and serving as a sizing device, and the air injection hole (105) is located at the bottom end of the needle rod.

3. The pipe end expanding and forming method with multiple steps of expanding, cleaning and cooling in one according to claim 1 or 2, characterized in that: The needle head surface of the trinity needle (1) is provided with a ceramic coating (6) and has a smooth surface, and the needle head surface hardness is ≥ HV3500.

4. The pipe end expanding and forming method with multiple steps of expanding, cleaning and cooling in one as claimed in claim 1, characterized in that: The airflow injected from the air injection hole (105) into the clean space (4) is a turbulent or spiral airflow.

5. The pipe end expanding and forming method with multiple steps of expanding, cleaning and cooling in one 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 expanding and forming method with multiple steps of expanding, cleaning and cooling in one as claimed in claim 1, characterized in that: The cross-sectional area of ​​the compressed gas channel (104) is greater than the cross-sectional area of ​​the clean space (4), so as to maintain an effective pressure difference.

7. The pipe end expanding and forming method with multiple steps of expanding, cleaning and cooling in one as claimed in 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 a diameter of the circle of the compressed gas channel where they are located.

8. The pipe end expanding and forming method with multiple steps of expanding, cleaning and cooling in one as claimed in claim 1, characterized in that: The three-in-one needle (1) also includes a needle seat (101), the outer shape of the needle seat is larger than the outer diameter of the needle rod, wherein the needle rod is larger than the length of the expanded inner hole (201) of the processed tube (2) and the end surface of the needle seat form a sewage discharge area (A).

9. The pipe end expanding and forming method with multiple steps of expanding, cleaning and cooling in one as claimed in claim 1 or 4, characterized in that: The compressed gas injected into the compressed gas channel (104) is dry cold air with a humidity range of 1% to 5% and a temperature of ≤25°C.

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