Process for on-line forming, annealing and preventing oxidation of female copper tube and structure thereof

Abstract

This invention discloses a process and structure for online forming, annealing, and oxidation prevention of internally threaded copper tubes, specifically relating to the field of internally threaded copper tubes. The process includes a raw material tray, on the left side of which are sequentially arranged an internal thread high-frequency forming machine, a chain-type drawing traction machine, a chipless cutting machine, an annealing mechanism, a cooling mechanism, a storage container, a cutting machine, and a semi-automatic U-bending machine. During operation, the annealing mechanism activates a heating coil via an external power supply. The energized heating coil generates a high-frequency magnetic field, which, through electromagnetic induction, heats the copper tube inside the annealing tube, achieving uniform heating. Simultaneously, as the copper tube is cut by the chipless cutting machine, a portion of the copper tube enters the annealing tube. The high-temperature annealing tube, combined with high-frequency induction heating, performs high-temperature annealing on the uniformly entering copper tube, causing the internal grains to rearrange and eliminating internal stress generated during forming. This reduces the hardness of the copper tube, increases its toughness, and ensures uniform hardness of the inner and outer walls of the copper tube.

Description

Technical Field

[0001] This invention relates to the field of internal threaded copper tube processing technology, specifically to the process and structure of online forming, annealing and anti-oxidation of internal threaded copper tubes. Background Technology

[0002] Due to their excellent thermal conductivity, structural strength, and heat exchange efficiency, internally threaded copper tubes are widely used in air conditioning, refrigeration, and HVAC fields. As downstream industries continue to increase their requirements for the dimensional accuracy, mechanical properties, and surface quality of precision copper tubes, the integrated production of online forming, annealing, and anti-oxidation of internally threaded copper tubes has become a core demand for industry development.

[0003] Currently, the production of internally threaded copper tubes mostly adopts a segmented processing mode, that is, the internal thread is formed first, then annealed separately, and finally cooled and processed. This production method has problems such as low production efficiency, complicated process connection, and easy surface scratches during copper tube transportation, making it difficult to meet the needs of large-scale, high-precision production.

[0004] In the annealing process, existing annealing equipment mostly uses medium-frequency heating, which mainly acts on the surface of the copper tube. This method results in poor heating uniformity, and when the copper tube wall thickness is large, it easily leads to an external heating and internal cooling phenomenon, resulting in insufficient recrystallization of the inner wall of the copper tube. This leads to significant differences in hardness between the front and rear sections and between the inner and outer walls, failing to meet the mechanical performance requirements of precision copper tubes. Simultaneously, during online production, the sealing section of the annealing equipment is relatively short, allowing air to easily mix into the protective atmosphere, such as nitrogen, causing defects such as oxidation, discoloration, and yellowing on the copper tube surface, affecting the surface finish and the quality of subsequent welding and processing. Therefore, this paper provides a process method and structure for online forming annealing and anti-oxidation of internally threaded copper tubes to solve the problems mentioned in the background art. Summary of the Invention

[0005] The purpose of this invention is to provide a process and structure for online forming, annealing and anti-oxidation of internally threaded copper tubes, so as to reduce the hardness of copper tubes, improve their toughness, and ensure the uniformity of hardness of the inner and outer walls of the copper tubes.

[0006] The objective of this invention can be achieved through the following technical solutions: The process and structure for online forming, annealing, and anti-oxidation of internally threaded copper tubes include a raw material tray. On the left side of the raw material tray, in sequence, are an internally threaded high-frequency forming machine, a chain-type drawing traction machine, a chipless cutting machine, an annealing mechanism, a cooling mechanism, a storage container, a cutting machine, and a semi-automatic U-bending machine. A support platform is fixedly connected to the bottom of the chipless cutting machine. The annealing mechanism includes annealing support blocks fixedly connected to the top surface of the support platform and arranged horizontally. A transverse guide groove is opened inside each annealing support block, and an inlet is opened on the right side of the right annealing support block, corresponding to the discharge port of the chipless cutting machine. Annealing tubes are fixedly connected to the inner sides of both annealing support blocks. Heating coils arranged in a threaded pattern are fixedly installed on the outer side of the annealing tubes. Both ends of the annealing tubes are sealed and fixed to the surface of the annealing support blocks by sealing caps.

[0007] As a further embodiment of the present invention: the annealing tube is a horizontally arranged high-purity fused silica tube, and the heating coil is a high-frequency induction heating coil.

[0008] As a further embodiment of the present invention: nitrogen grooves are provided on the top of the two annealing support blocks, the nitrogen grooves are vertically connected to the corresponding conduit grooves, and a nitrogen pipe is fixedly connected to the top of the nitrogen grooves, and an existing nitrogen supply device is fixedly connected to the other end of the nitrogen pipe.

[0009] As a further aspect of the present invention: the cooling mechanism includes a cooling pipe, the right end of which is fixedly connected to the surface of the left annealing support block via a sealing cap II, thereby achieving a sealed connection between the cooling mechanism and the annealing mechanism and ensuring that the protective atmosphere does not leak; the cooling pipe has an annular cylindrical cooling chamber inside, and a pair of left and right arranged partition rings are fixedly connected inside the cooling chamber, which divides the cooling chamber into three independent cavities: left, middle, and right, and the three cavities can independently receive and discharge coolant.

[0010] As a further embodiment of the present invention: a set of transversely arranged threaded guide plates are fixedly connected inside the cooling cavity.

[0011] As a further embodiment of the present invention: a main support is provided on the rear side of the cooling pipe, and auxiliary supports arranged on the left and right are fixedly connected to the front side of the main support. The two auxiliary supports are fixedly connected to the cooling pipe to achieve stable support for the cooling pipe. A liquid distribution box is fixedly connected to the top of the main support. The liquid distribution box is hollow inside and has an inlet pipe fixedly connected to its rear side. The other end of the inlet pipe is connected to the output end of the chiller. The front wall of the liquid distribution box has three outlets arranged horizontally from left to right: outlet one, outlet two, and outlet three. The cross-section of outlet one and outlet two is the same, while the cross-section of outlet three is larger. A set of liquid guiding hoses is fixedly connected to the front side of the liquid distribution box. The set of liquid guiding hoses corresponds to the three outlets and the other end of the liquid guiding hoses is connected to the surface of the cooling pipe. A set of liquid outlet hoses is fixedly connected to the bottom of the cooling chamber. A connector is fixedly connected to the other side of the liquid outlet hoses. A discharge pipe is fixedly connected to the rear side of the connector. The discharge pipe is fixedly connected to the input end of the chiller.

[0012] As a further embodiment of the present invention: a temperature sensor 1 and a temperature sensor 2 are fixedly installed in the left and right sections of the cooling chamber, respectively; a mounting bracket is fixedly connected to the right side of the liquid separator, a cylinder is fixedly installed on the left side wall of the mounting bracket, a sliding rod is fixedly connected to the output end of the cylinder, the sliding rod passes through the right wall of the liquid separator, and a sliding sealing sleeve is provided at the connection between the liquid separator and the sliding rod to ensure the sealing of the liquid separator; a partition 1 and a partition 2 arranged on the left and right are fixedly connected to the bottom of the sliding rod; a controller is installed on the main bracket, and the controller is electrically connected to the chiller, the pump body, the two temperature sensors and the cylinder, respectively.

[0013] This invention also provides a process for online forming, annealing, and oxidation prevention of internally threaded copper tubes, comprising the following steps: S1. Pass the copper tubes on the raw material tray through the internal thread high-frequency forming machine and the chain drawing traction machine in sequence to complete the pipeline connection and sealing inspection. Preset the working parameters of each equipment to ensure that there is no leakage and no abnormality. S2. Start the chain-type drawing traction machine, which drives the copper tube to move at a constant speed. Through the high-frequency internal thread forming machine, the copper tube's inner wall thread is formed under the assistance of high-frequency induction heating, forming an internal thread structure that meets the requirements. Then, the chipless cutting machine cuts the copper tube to a fixed length. S3. The formed copper tube is sent to the annealing mechanism. Under the protection of high-purity nitrogen, uniform annealing is achieved by high-frequency induction heating to eliminate the internal stress generated during the forming process and ensure the stability of the copper tube performance. S4. After annealing, the copper tube enters the segmented cooling chamber and achieves uniform cooling through a preset gradient cooling system to avoid local overheating or insufficient cooling. The entire process maintains an oxygen-free environment to prevent oxidation. S5. After cooling, the copper tubes undergo specification testing and are then subjected to subsequent bending and finishing processes to finally obtain qualified internally threaded copper tube products.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The process and structure of this online forming, annealing and anti-oxidation process for internally threaded copper tubes involve using an annealing mechanism that activates a heating coil via an external power source. The energized coil generates a high-frequency magnetic field, which, through electromagnetic induction, heats the copper tube itself, achieving uniform heating. Simultaneously, as the copper tube is cut by a chipless cutter, a portion of the tube enters the annealing tube. The high-temperature annealing tube, combined with high-frequency induction heating, performs high-temperature annealing on the uniformly entering copper tube, causing the internal grains to rearrange and eliminating internal stress generated during forming. This reduces the hardness of the copper tube, increases its toughness, and ensures uniform hardness of the inner and outer walls.

[0015] Furthermore, the process and structure of the online forming, annealing, and anti-oxidation of the internally threaded copper tube involves pumping constant-temperature coolant from the chiller into the inlet pipe, then into the distribution box. The coolant, after entering the distribution box, is discharged through different outlets. Since the three outlet sections are the largest, the amount of coolant entering the right section of the cooling chamber is also the largest under the same delivery pressure. With the three sections of the cooling chamber having the same size, the right section, directly facing the high-temperature annealed copper tube, can quickly remove a large amount of heat from the copper tube surface, achieving a strong cooling effect and preventing performance fluctuations caused by the high-temperature copper tube remaining at high temperatures for extended periods. After entering different sections of the cooling chamber, the coolant forms a spiral flow along the wall under the guidance of the threaded guide plates, fully contacting the inner wall of the cooling tube and improving heat exchange efficiency. Finally, through the outlet hose and connector, it is discharged back to the chiller via the discharge pipe. The chiller then cools the high-temperature coolant, restoring it to constant-temperature coolant, achieving a circulating liquid cooling effect. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure of the online forming annealing and anti-oxidation process for internally threaded copper tubes; Figure 2 This is a schematic diagram of the annealing mechanism in the online forming annealing and oxidation prevention process of internally threaded copper tubes. Figure 3 A schematic cross-sectional view of the annealing mechanism in the process method and structure for online forming annealing and oxidation prevention of internally threaded copper tubes; Figure 4 This is a schematic diagram of the cooling mechanism in the online forming annealing and anti-oxidation process of internally threaded copper tubes. Figure 5 A schematic diagram of the cooling pipe cross-section structure in the process method and structure of online forming annealing and anti-oxidation of internally threaded copper tubes; Figure 6This is a schematic diagram of the cross-sectional structure of the separator box in the process method and structure of online forming annealing and anti-oxidation of internally threaded copper tubes.

[0017] In the diagram: 10. Raw material tray; 11. High-frequency internal thread forming machine; 12. Chain-type drawing traction machine; 13. Support platform; 14. Chipless cutting machine; 20. Annealing mechanism; 201. Annealing support block; 202. Annealing tube; 203. Heating coil; 204. Guide groove; 205. Inlet; 206. Nitrogen tank; 207. Nitrogen pipe; 208. Sealing cover one; 209. Sealing cover two; 30. Cooling mechanism; 301. Cooling pipe; 302. Cooling chamber; 303, partition ring; 304, threaded guide plate; 305, liquid inlet pipe; 306, liquid distribution box; 307, liquid inlet hose; 308, liquid outlet hose; 309, connector; 310, discharge pipe; 311, liquid outlet one; 312, liquid outlet two; 313, liquid outlet three; 314, mounting bracket; 315, cylinder; 316, sliding rod; 317, partition one; 318, partition two; 319, main bracket; 320, auxiliary bracket.

[0018] like Figures 1-6 As shown, the process and structure of online forming, annealing and anti-oxidation of internal threaded copper tubes include a raw material tray 10. On the left side of the raw material tray 10, there are, in sequence, an internal thread high-frequency forming machine 11, a chain drawing traction machine 12, a chipless cutting machine 14, an annealing mechanism 20, a cooling mechanism 30, a storage container, a cutting machine and a semi-automatic U-bending machine.

[0019] Before the copper tube forming process, the copper tubes on the raw material tray 10 are sequentially passed through the internal thread high-frequency forming machine 11 and connected to the chain drawing traction machine 12. Then, the movable end of the copper tube is connected to the chipless cutting machine 14. The chain drawing traction machine 12 provides traction force, pulling the copper tubes wound on the surface of the raw material tray 10, causing the copper tubes to move continuously to the left at a uniform speed. While the copper tubes are moving, the part in contact with the internal thread high-frequency forming machine 11 undergoes plastic deformation under the action of high-frequency induction. The forming die extrudes and forms an internal thread structure, completing the internal thread forming. The formed copper tubes maintain a uniform speed and are then cut by the chipless cutting machine 14. The cutting machine 14 performs a fixed-length chipless cut on the formed copper tube. The cut copper tube enters the annealing mechanism 20 through the inlet 205. Under the protection of high-purity nitrogen, it is annealed at high temperature by high-frequency induction heating by the heating coil 203 to eliminate internal stress. The annealed high-temperature copper tube enters the cooling mechanism 30 and is rapidly cooled to the qualified temperature through the gradient adaptive cooling of the three-stage cooling chamber 302. The cooled copper tube enters the storage container for cycle buffering, and then is finally finely adjusted to the fixed length by the cutting machine. Finally, it is sent to the semi-automatic U-bending machine to complete the bending and forming, and finally obtains a qualified internal thread bent U-shaped copper tube.

[0020] refer to Figures 1-6The bottom of the chipless cutting machine 14 is fixedly connected to a support platform 13. The annealing mechanism 20 includes annealing support blocks 201 fixedly connected to the top surface of the support platform 13 and arranged in a left-right configuration. The annealing support blocks 201 have a transverse guide groove 204 inside. The right side of the right annealing support block 201 has an inlet 205. The inlet 205 corresponds to the discharge port of the chipless cutting machine 14, ensuring that the copper tube cut by the chipless cutting machine 14 can accurately enter the guide groove 204. The inner sides of the two annealing support blocks 201 are fixedly connected to an annealing tube 202. The outer side of the annealing tube 202 is fixedly installed with a threaded heating coil 203. The two ends of the annealing tube 202 are sealed and fixed to the surface of the annealing support blocks 201 by a sealing cap 208, realizing the sealed installation of the annealing tube 202 and preventing leakage of the internal protective atmosphere and the entry of external air.

[0021] Preferably, the annealing tube 202 uses a horizontally arranged high-purity fused silica tube (temperature resistance ≥1250℃) as the core annealing cavity. It has excellent insulation properties and does not interfere with the high-frequency magnetic field. It is also transparent and visible, allowing for real-time monitoring of the copper tube's annealing status and facilitating timely detection of abnormalities during the annealing process. The heating coil 203 is a high-frequency induction heating coil with an adjustable operating frequency of 25-45kHz and a heating efficiency >90%. It can achieve uniform heating of the copper tube in both the radial and axial directions, avoiding problems such as local overheating or insufficient heating.

[0022] Existing copper tube annealing devices suffer from poor temperature uniformity during copper tube annealing. Medium-frequency heating mainly acts on the surface of the tube, and when the tube wall thickness is large, the phenomenon of external heat and internal coldness easily occurs, resulting in insufficient recrystallization of the inner wall and significant differences in hardness between the front and rear sections and between the inner and outer walls of the entire tube, which cannot meet the performance requirements of precision copper tubes. In contrast, the annealing mechanism 20 starts the heating coil 203 through an external power supply. After the heating coil 203 is energized, it generates a high-frequency magnetic field, which causes the copper tube inside the annealing tube 202 to heat up through electromagnetic induction, achieving uniform heating. While the copper tube is being cut by the chipless cutter 14, part of the copper tube simultaneously enters the annealing tube 202. The high-temperature annealing tube 202, combined with high-frequency induction heating, performs high-temperature annealing on the copper tube that enters at a uniform speed, causing the internal grains of the copper tube to rearrange, eliminating the internal stress generated during the forming process, reducing the hardness of the copper tube, improving its toughness, and ensuring uniform hardness and stable performance of the inner and outer walls of the copper tube, thus meeting the subsequent processing and use requirements of precision copper tubes.

[0023] Furthermore, nitrogen gas grooves 206 are provided on the top of the two annealing support blocks 201. The nitrogen gas grooves 206 are vertically connected to the corresponding conduit grooves 204, and a nitrogen pipe 207 is fixedly connected to the top of the nitrogen gas grooves 206. The other end of the nitrogen pipe 207 is fixedly connected to an existing nitrogen supply device (such as a nitrogen cylinder, nitrogen pressure regulator and flow meter combination), which can realize the stable supply and flow regulation of nitrogen, and ensure the stability of the protective atmosphere during the annealing process.

[0024] During annealing, copper tubes are often protected with gas. However, existing gas protection methods are unstable. Due to the short sealing section in online production, air can easily mix in with protective atmospheres such as nitrogen and ammonia decomposition gas, leading to defects such as slight oxidation, discoloration, and yellowing on the tube surface, affecting subsequent welding and surface acceptance. In this device, during annealing, the nitrogen supply device introduces high-purity nitrogen into the nitrogen tank 206 through the nitrogen pipe 207. The nitrogen flows from the nitrogen tank 206 into the guide tube 204 and then into the annealing tube 202, gradually replacing the air inside the annealing tube 202, allowing the copper tube to complete annealing in an oxygen-free nitrogen atmosphere. At the same time, both ends of the annealing tube 202 are sealed with sealing caps 208, which, together with the sealing structure of the subsequent cooling mechanism 30, forms a fully sealed protective channel, effectively preventing air from mixing in and completely avoiding defects such as oxidation and discoloration on the copper tube surface. This ensures the smoothness of the copper tube surface, improves the product qualification rate, and provides an oxygen-free environment for the subsequent cooling process.

[0025] refer to Figures 1-6 The cooling mechanism 30 includes a cooling pipe 301. The right end of the cooling pipe 301 is fixedly connected to the surface of the left annealing support block 201 through a sealing cap 209, so as to achieve a sealed connection between the cooling mechanism 30 and the annealing mechanism 20 and ensure that the protective atmosphere does not leak. The cooling pipe 301 has an annular cylindrical cooling chamber 302 inside. A pair of left and right arranged partition rings 303 are fixedly connected inside the cooling chamber 302. The partition rings 303 divide the cooling chamber 302 into three independent cavities: left, middle and right. The three cavities of the cooling chamber 302 can independently enter and exit the coolant, so as to achieve segmented independent cooling and facilitate precise control of the cooling intensity of each segment.

[0026] Preferably, a set of transversely arranged threaded guide plates 304 are fixedly connected inside the cooling chamber 302; the threaded guide plates 304 can guide the coolant to flow spirally along the inner wall of the cooling pipe 301, force the coolant to flow along the wall, eliminate stagnant water areas in the cooling chamber 302, avoid uneven local cooling, and at the same time increase the contact area between the coolant and the cooling pipe 301, improve heat exchange efficiency, ensure uniform and rapid cooling of the copper pipe, and prevent defects such as bending, ellipticing, and springback of the copper pipe due to uneven cooling.

[0027] Specifically, a main support 319 is provided on the rear side of the cooling pipe 301. Auxiliary supports 320 arranged on the left and right sides are fixedly connected to the front side of the main support 319. The two auxiliary supports 320 are fixedly connected to the cooling pipe 301 to achieve stable support for the cooling pipe 301. A liquid distribution box 306 is fixedly connected to the top of the main support 319. The liquid distribution box 306 is hollow inside and has a liquid inlet pipe 305 fixedly connected to its rear side. The other end of the liquid inlet pipe 305 is connected to the output end of the chiller. The front wall of the liquid distribution box 306 has three horizontally arranged outlets from left to right: outlet one 311, outlet two 312, and outlet three 313. 11 has the same cross-section as outlet 2 312, while outlet 313 has a larger cross-section. A set of liquid guiding hoses 307 are fixedly connected to the front side of the liquid distribution box 306. The set of liquid guiding hoses 307 corresponds to the three liquid outlets and the other end of the liquid guiding hoses 307 is connected to the surface of the cooling pipe 301 to realize liquid delivery to different sections of the cooling chamber 302. A set of liquid outlet hoses 308 are fixedly connected to the bottom of the cooling chamber 302. A connector 309 is fixedly connected to the other side of the liquid outlet hoses 308. A discharge pipe 310 is fixedly connected to the rear side of the connector 309. The discharge pipe 310 is fixedly connected to the input end of the chiller to form a coolant circulation loop.

[0028] Existing cooling devices lack sufficient cooling control precision and mostly employ air cooling or simple spraying methods. The cooling rate cannot be precisely adjusted, making it difficult to balance the pipe's softness, grain size, and resilience performance. In contrast, this cooling mechanism 30 achieves circulating water cooling through a chiller, ensuring a constant liquid temperature (maintained at 18-22℃) inside the cooling chamber 302. Simultaneously, the pump pressurizes and delivers the coolant from the chiller, ensuring stable coolant flow and efficient heat exchange.

[0029] During operation, the constant-temperature coolant from the chiller is pumped into the inlet pipe 305 and then into the distributor box 306. The coolant in the distributor box 306 is discharged through different outlets. Since outlet 313 has the largest cross-section, the amount of coolant entering the right section of the cooling chamber 302 is also the largest under the same delivery pressure. With all three sections of the cooling chamber 302 having the same size, the right section of the cooling chamber 302, which directly faces the annealed high-temperature copper tube, can quickly remove a large amount of heat from the copper tube surface, achieving a strong cooling effect and preventing performance fluctuations caused by the high-temperature copper tube remaining at high temperatures for extended periods. The coolant entering the cooling chamber 302... After different sections, a spiral flow is formed under the guidance of the threaded guide plate 304, which fully contacts the inner wall of the cooling pipe 301 to improve heat exchange efficiency. Finally, the liquid is discharged back to the chiller through the outlet hose 308 and connector 309 and the discharge pipe 310. The chiller cools the high-temperature coolant and turns it back into a constant-temperature coolant, achieving the effect of circulating liquid cooling. Furthermore, by dividing the cooling chamber 302 into sections, the cooling intensity of each section can be precisely controlled according to the temperature change of the copper pipe during the cooling process, forming a gradient cooling of weak left, stable middle, and strong right, which takes into account both the cooling efficiency and performance stability of the copper pipe and avoids internal stress or deformation of the copper pipe due to sudden cooling.

[0030] Furthermore, temperature sensor one and temperature sensor two (not shown in the figure, both are existing conventional temperature sensors) are fixedly installed in the left and right sections of the cooling chamber 302, respectively; a mounting bracket 314 is fixedly connected to the right side of the liquid distribution box 306, and a cylinder 315 is fixedly installed on the left side wall of the mounting bracket 314. A sliding rod 316 is fixedly connected to the output end of the cylinder 315. The sliding rod 316 penetrates the right wall of the liquid distribution box 306, and a sliding sealing sleeve is provided at the connection between the liquid distribution box 306 and the sliding rod 316 to ensure the sealing of the liquid distribution box 306 and prevent coolant leakage; partitions one 317 and partition two 318 arranged on the left and right sides are fixedly connected to the bottom of the sliding rod 316; a controller (not shown in the figure) is installed on the main bracket 319. The controller is electrically connected to the chiller, pump body, two temperature sensors and cylinder 315 to realize automatic control of the cooling process.

[0031] When the cooling mechanism 30 is not activated, the output end of cylinder 315 is fixed, causing outlet 313 to be covered by partition 317, while partition 318 is located to the right of outlet 311, leaving outlet 311 uncovered. At this time, the three outlets have the same cross-section. In the early stages of copper tube forming, the annealing mechanism 20 and cooling mechanism 30 must be activated in advance because there is a preheating phase. During this phase, since the annealed high-temperature copper tube has not yet entered the cooling pipe 301, the temperatures of the three sections of the cooling chamber 302 are consistent. The temperature data fed back to the controller by the temperature sensors are the same, so the controller controls the cylinder 315 to remain stationary. The coolant entering the distribution box 306 will be evenly distributed to the three outlets, so that the flow rate and volume of coolant entering the three sections of the cooling chamber 302 are the same. At this time, the three sections of the cooling chamber 302 are cooled evenly, which can preheat the cooling pipe 301 and avoid local sudden cooling deformation of the copper pipe due to excessive temperature difference when the high-temperature copper pipe enters later. At the same time, it ensures that the cooling system is in a stable standby state, preparing for subsequent adaptive cooling.

[0032] When the annealed high-temperature copper tube enters the cooling pipe 301, the copper tube first enters the right side of the cooling pipe 301, causing the temperature of the right section of the cooling chamber 302 to rise rapidly. This results in a discrepancy in the temperatures detected by the two temperature sensors (the temperature of the right section is higher than that of the left section). The controller receives the temperature data fed back by the two temperature sensors in real time and compares the two sets of data. Then, based on the temperature difference, it controls the extension distance of the output end of the cylinder 315 (the higher the temperature difference, the longer the extension of the output end of the cylinder 315). The extension of the output end of the cylinder 315 drives the sliding rod 316 to move to the left, which in turn drives the partition 317 to gradually move away from the liquid outlet 313, thus reducing the coverage of the liquid outlet 313. As the volume decreases, the outlet cross-section gradually increases, resulting in more coolant entering outlet 313. Simultaneously, baffle 2 318 gradually covers outlet 1 311, making the cross-section of outlet 1 311 smaller and smaller, thus reducing the amount of coolant entering outlet 1 311. This adjustment process perfectly meets the cooling requirements of the copper tube after annealing: since the temperature of the annealed copper tube drops rapidly after the strong cooling of the right section and the normal cooling of the middle section, only a small amount of coolant is needed for the left section for slow cooling. This ensures that the copper tube is thoroughly cooled to the qualified temperature (≤60℃) and avoids overcooling of the left section, which could cause the copper tube to spring back and deform, thus ensuring the dimensional accuracy and mechanical properties of the copper tube are stable.

[0033] Similarly, after the entire device stops operating, since no more high-temperature copper pipes enter the cooling pipe 301, there is no longer a heat source inside the cooling pipe 301. As the cooling mechanism 30 continues to operate, the temperature of the right section of the cooling chamber 302 gradually decreases, and the temperature difference between the temperature data fed back by the two temperature sensors becomes smaller and smaller. Therefore, the controller will control the output end of the cylinder 315 to slowly retract, driving the sliding rod 316 to move to the right, so that the coverage area of ​​the liquid outlet 311 gradually decreases and the cross-section becomes larger, while the coverage area of ​​the liquid outlet 313 gradually increases and the cross-section becomes smaller and smaller, until the cross-sections of the three liquid outlets return to the same, so that the liquid inflow of the three sections of the cooling chamber 302 gradually becomes the same. This flexible shutdown adjustment method can avoid the deformation and cracking of the small amount of copper pipe tail end remaining in the cooling pipe 301 due to local overcooling, and at the same time, it can make the cooling system return to the initial state smoothly, reduce the damage of water flow impact to pipes, seals and sensors, extend the service life of the equipment, and no recalibration is required when starting up next time, and it can quickly enter a stable working state.

[0034] This invention also provides a process for online forming, annealing, and oxidation prevention of internally threaded copper tubes, comprising the following steps: S1. Pass the copper tubes on the raw material tray through the internal thread high-frequency forming machine 11 and the chain drawing traction machine 12 in sequence to complete the pipeline connection and sealing check, preset the working parameters of each equipment, and ensure that there is no leakage or abnormality. S2. Start the chain-type pulling traction machine 12, which drives the copper tube to move at a constant speed. Through the internal thread high-frequency forming machine 11, the copper tube internal wall thread is formed under the assistance of high-frequency induction heating, forming an internal thread structure that meets the requirements. Then the chipless cutting machine 14 cuts the copper tube to a fixed length. S3. The formed copper tube is sent into the annealing mechanism 20. Under the protection atmosphere of high-purity nitrogen, uniform annealing is achieved by high-frequency induction heating to eliminate the internal stress generated during the forming process and ensure the stability of the copper tube performance. S4. After annealing, the copper tube enters the segmented cooling chamber 302. Through the preset gradient cooling system, uniform cooling is achieved to avoid local overheating or insufficient cooling. The entire process maintains an oxygen-free environment to prevent oxidation.

[0035] S5. After cooling, the copper tubes undergo specification testing and are then subjected to subsequent bending and finishing processes to finally obtain qualified internally threaded copper tube products.

[0036] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. An online forming, annealing, and anti-oxidation structure for internally threaded copper tubes, comprising a raw material tray (10), wherein the left side of the raw material tray (10) is sequentially provided with an internally threaded high-frequency forming machine (11), a chain-type drawing traction machine (12), a chipless cutting machine (14), an annealing mechanism (20), a cooling mechanism (30), a storage container, a cutting machine, and a semi-automatic U-bending machine; characterized in that, The bottom of the chipless cutting machine (14) is fixedly connected to a support platform (13). The annealing mechanism (20) includes annealing support blocks (201) fixedly connected to the top surface of the support platform (13) and arranged in a left-right manner. The annealing support blocks (201) have a transverse guide groove (204) inside. The right side of the right annealing support block (201) has an inlet (205) on its right side. The inlet (205) corresponds to the discharge port of the chipless cutting machine (14). The inner sides of the two annealing support blocks (201) are fixedly connected to an annealing tube (202). The outer side of the annealing tube (202) is fixedly installed with a threaded heating coil (203). The two ends of the annealing tube (202) are sealed and fixed to the surface of the annealing support block (201) by a sealing cap (208).

2. The online forming annealing and anti-oxidation structure for internally threaded copper tubes according to claim 1, characterized in that, The annealing tube (202) is a horizontally arranged high-purity fused silica tube, and the heating coil (203) is a high-frequency induction heating coil.

3. The online forming annealing and anti-oxidation structure for internally threaded copper tubes according to claim 2, characterized in that, The top of the two annealing support blocks (201) is provided with a nitrogen tank (206), the nitrogen tank (206) is vertically connected to the corresponding conduit tank (204), and the top of the nitrogen tank (206) is fixedly connected to a nitrogen pipe (207), the other end of the nitrogen pipe (207) is fixedly connected to an existing nitrogen supply device.

4. The online forming annealing and anti-oxidation structure for internally threaded copper tubes according to claim 3, characterized in that, The cooling mechanism (30) includes a cooling pipe (301). The right end of the cooling pipe (301) is fixedly connected to the surface of the left annealing support block (201) through a sealing cap (209), so as to achieve a sealed connection between the cooling mechanism (30) and the annealing mechanism (20) and ensure that the protective atmosphere does not leak. The cooling pipe (301) has an annular cylindrical cooling chamber (302) inside. The cooling chamber (302) is fixedly connected with a pair of left and right arranged partition rings (303). The partition rings (303) divide the cooling chamber (302) into three independent cavities: left, middle and right. The three cavities of the cooling chamber (302) can independently enter and exit the coolant.

5. The online forming annealing and anti-oxidation structure for internally threaded copper tubes according to claim 4, characterized in that, A set of transversely arranged threaded guide plates (304) are fixedly connected inside the cooling cavity (302).

6. The online forming annealing and anti-oxidation structure for internally threaded copper tubes according to claim 5, characterized in that, A main support (319) is provided on the rear side of the cooling pipe (301). Auxiliary supports (320) arranged on the left and right sides are fixedly connected to the front side of the main support (319). The two auxiliary supports (320) are fixedly connected to the cooling pipe (301) to achieve stable support for the cooling pipe (301). A liquid distribution box (306) is fixedly connected to the top of the main support (319). The liquid distribution box (306) is hollow inside and has an inlet pipe (305) fixedly connected to its rear side. The other end of the inlet pipe (305) is connected to the output end of the chiller. The front wall of the liquid distribution box (306) has horizontally arranged outlets 1 (311), 2 (312), and 3 (313) from left to right. 313), wherein the cross-section of outlet one (311) and outlet two (312) are the same, while the cross-section of outlet three (313) is larger; a set of liquid guiding hoses (307) are fixedly connected to the front side of the liquid distribution box (306), the set of liquid guiding hoses (307) corresponds to the three liquid outlets and the other end of the liquid guiding hoses (307) is connected to the surface of the cooling pipe (301); a set of liquid outlet hoses (308) are fixedly connected to the bottom of the cooling chamber (302), the other side of the liquid outlet hoses (308) is fixedly connected to the connector (309), the rear side of the connector (309) is fixedly connected to the discharge pipe (310), and the discharge pipe (310) is fixedly connected to the input end of the chiller.

7. The online forming annealing and anti-oxidation structure for internally threaded copper tubes according to claim 6, characterized in that, Temperature sensor 1 and temperature sensor 2 are fixedly installed in the left and right sections of the cooling chamber (302), respectively; a mounting bracket (314) is fixedly connected to the right side of the liquid distribution box (306), and a cylinder (315) is fixedly installed on the left side wall of the mounting bracket (314). A sliding rod (316) is fixedly connected to the output end of the cylinder (315). The sliding rod (316) penetrates the right wall of the liquid distribution box (306), and a sliding sealing sleeve is provided at the connection between the liquid distribution box (306) and the sliding rod (316) to ensure the sealing of the liquid distribution box (306); a partition plate 1 (317) and a partition plate 2 (318) arranged on the left and right sides are fixedly connected to the bottom of the sliding rod (316); a controller is installed on the main bracket (319), and the controller is electrically connected to the chiller, the pump body, the two temperature sensors and the cylinder (315).

8. A process for online forming, annealing, and oxidation prevention of internally threaded copper tubes, characterized in that... Includes the following steps: S1. Pass the copper tubes on the raw material tray through the internal thread high-frequency forming machine (11) and the chain drawing traction machine (12) in sequence to complete the pipeline connection and sealing inspection, preset the working parameters of each equipment, and ensure that there is no leakage or abnormality. S2. Start the chain-type pulling traction machine (12), which drives the copper tube to move at a constant speed. Through the internal thread high-frequency forming machine (11), the copper tube internal wall thread is formed under the assistance of high-frequency induction heating, forming an internal thread structure that meets the requirements. Then the chipless cutting machine (14) cuts the copper tube to a fixed length. S3. The formed copper tube is sent into the annealing mechanism (20). Under the protection atmosphere of high-purity nitrogen, uniform annealing is achieved by high-frequency induction heating to eliminate the internal stress generated during the forming process and ensure the stability of the copper tube performance. S4. After annealing, the copper tube enters the segmented cooling chamber (302). Through the preset gradient cooling system, uniform cooling is achieved to avoid local overheating or insufficient cooling. The entire process maintains an oxygen-free environment to prevent oxidation. S5. After cooling, the copper tubes undergo specification testing and are then subjected to subsequent bending and finishing processes to finally obtain qualified internally threaded copper tube products.

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