Annealing and anti-oxidation device for wire drawing machine

Abstract

This invention discloses an anti-oxidation device for annealing of a wire drawing machine, relating to the field of cable manufacturing technology. It includes a nitrogen generator, a bakelite pipe, and a preheating unit located between the annealing unit and the bakelite pipe. The bakelite pipe has an anti-oxidation chamber for the wire to pass through. The preheating unit includes a preheating chamber, a vent pipe, a guide pipe, and a return pipe. The preheating chamber has an exothermic chamber for the wire to pass through and an absorbent chamber, which are spaced apart on the outer periphery of the exothermic chamber. The vent pipe connects to the inlets of the nitrogen generator and the absorbent chamber. The guide pipe connects to the outlet of the bakelite pipe and the inlet of the absorbent chamber. The return pipe connects to the inlet of the bakelite pipe and the outlet of the absorbent chamber. This invention improves product consistency and yield.

Description

Technical Field

[0001] This invention relates to the field of cable production technology, specifically to an anti-oxidation device for wire drawing machine annealing. Background Technology

[0002] In the cable manufacturing industry, copper wire drawing machines are typically equipped with continuous annealing units to eliminate work hardening that occurs during the cold drawing process, restoring the copper wire's conductivity and ductility. During the annealing process, the copper wire is at a high temperature (usually 400-600℃), making it highly susceptible to reacting with oxygen in the air, resulting in the formation of an oxide layer on the surface (turning black or red), which severely affects conductor quality and subsequent processing.

[0003] Currently, the industry commonly adopts the process of introducing protective gas into the annealing tube and the sealing cavity. However, the protective gas is usually directly introduced into the annealing cavity at room temperature (about 20-40°C), while the surface temperature of the copper wire after annealing and heating is as high as 400-600°C, resulting in a huge temperature difference of hundreds of degrees Celsius between the two.

[0004] The rapid cooling of the copper wire surface creates a thermal shock effect, which causes lattice distortion and residual stress in the copper crystal structure after recrystallization due to the rapid cooling. This weakens the actual effect of annealing in eliminating work hardening, resulting in batch-to-batch fluctuations in key performance indicators such as elongation and conductivity of the copper wire. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-oxidation device for annealing of wire drawing machines to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an anti-oxidation device for annealing of a wire drawing machine, suitable for use between an annealing unit and a cooling unit, comprising a nitrogen generator, a bakelite pipe, and a preheating unit disposed between the annealing unit and the bakelite pipe, wherein the bakelite pipe is provided with an anti-oxidation chamber for the wire to pass through;

[0007] The preheating unit includes:

[0008] The preheating box has a heat release chamber for the wire to pass through, and the preheating box also has a heat absorption chamber, which is spaced around the outer periphery of the heat release chamber;

[0009] A vent pipe connects the nitrogen generator and the heat absorption chamber to the air inlet.

[0010] A vent pipe, connecting the outlet of the bakelite pipe and the inlet of the heat absorption chamber; and

[0011] The return air pipe connects the air inlet of the bakelite pipe and the air outlet of the heat absorption chamber.

[0012] Furthermore, the preheating box is also provided with a heat-conducting cavity, which is located between the heat-absorbing cavity and the heat-releasing cavity;

[0013] The preheating unit also includes a phase change material disposed within the heat-conducting cavity.

[0014] Furthermore, the preheating unit also includes a heat-conducting frame disposed within the heat-conducting cavity, the heat-conducting frame having a storage cavity for holding the phase change material.

[0015] Furthermore, the inner wall of the storage cavity is provided with a diaphragm, which divides the storage cavity into a phase change cavity and a gas cavity. The phase change cavity is used to hold the phase change material, and the gas cavity is used to hold the gas.

[0016] The preheating unit also includes a pressure sensor located in the air chamber, an electrically controlled valve located in the return air pipe, and a control structure that is communicatively connected to the pressure sensor and the electrically controlled valve. The electrically controlled valve is used to control the opening degree of the return air pipe.

[0017] Furthermore, the control structure is also used to acquire the linear speed signal and annealing current signal of the wire drawing machine host. The control structure calculates the estimated heat value of the current wire entering the heat release chamber based on the linear speed signal and the annealing current signal, and generates a feedforward control signal based on the estimated heat value. The feedforward control signal is superimposed on the feedback signal of the air pressure sensor to jointly control the opening degree of the electronically controlled valve.

[0018] Furthermore, the porosity of the thermally conductive skeleton is 60%-90%.

[0019] Furthermore, the heat-conducting cavity is sequentially configured with multiple temperature zones along the direction of wire travel. The phase change materials in different temperature zones are different, and the melting point of the phase change materials increases sequentially from the air inlet to the air outlet of the heat-absorbing cavity.

[0020] Furthermore, a traveling cylinder is provided inside the heat absorption chamber, the traveling cylinder is rotatably connected to the preheating box, and a spiral blade is fixed to the outer periphery of the traveling cylinder.

[0021] Furthermore, ball bearings are installed on the sidewalls of the helical blades, and the ball bearings abut against the inner wall of the heat absorption box.

[0022] Compared with existing technologies, the beneficial effects of this invention are as follows: By adding a preheating unit between the annealing unit and the bakelite pipe, the residual heat radiated outward when the high-temperature wire passes through the exothermic chamber is used to preheat the nitrogen flowing through the absorbent chamber, so that the nitrogen is heated to near the wire temperature before entering the bakelite pipe. This effectively reduces the temperature difference between the nitrogen and the high-temperature copper wire, avoids the thermal shock effect caused by room-temperature nitrogen directly scouring the high-temperature copper wire, eliminates the lattice distortion and residual stress caused by rapid cooling of the copper crystal structure, and keeps the key performance indicators such as elongation and conductivity of the annealed copper wire stable, thereby improving product consistency and yield. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the installation location of the anti-oxidation device for the annealing of the wire drawing machine according to the present invention;

[0024] Figure 2 This is a cross-sectional view of the annealing and anti-oxidation device for the wire drawing machine of the present invention;

[0025] Figure 3 for Figure 2 A magnified view of part A in the diagram.

[0026] In the diagram: 10, Annealing unit; 20, Cooling unit; 30, Bakelite pipe; 40, Preheating unit; 401, Preheating box; 4011, Heat release chamber; 4012, Heat absorption chamber; 4013, Heat conduction chamber; 402, Vent pipe; 403, Air guide pipe; 404, Air return pipe; 405, Phase change material; 406, Heat-conducting frame; 4061, Heat insulation ring; 4062, Storage cavity; 4063, Diaphragm; 4064, Phase change cavity; 4065, Gas cavity; 50, Traveling cylinder; 501, Spiral blade; 5011, Ball bearing. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] like Figures 1-3 As shown, the present invention provides a technical solution: an anti-oxidation device for annealing of a wire drawing machine, applicable between an annealing unit 10 and a cooling unit 20, including a nitrogen generator, a bakelite pipe 30, and a preheating unit 40 disposed between the annealing unit 10 and the bakelite pipe 30, wherein the bakelite pipe 30 is provided with an anti-oxidation chamber for the wire to pass through.

[0029] The gaps at both ends of the bakelite pipe 30, through which the wires pass, form an exhaust channel. The nitrogen generator continuously supplies fresh nitrogen, and excess nitrogen is discharged through this gap, maintaining a slight positive pressure inside the anti-oxidation chamber and preventing external air from entering.

[0030] The preheating unit 40 includes a preheating box 401, a vent pipe 402, a guide pipe 403, and a return pipe 404. The preheating box 401 has a heat release chamber 4011 for the wire to pass through, and the preheating box 401 also has a heat absorption chamber 4012, which is spaced around the outer periphery of the heat release chamber 4011. The vent pipe 402 is connected to the nitrogen generator and the air inlet of the heat absorption chamber 4012. The guide pipe 403 is connected to the air outlet of the bakelite pipe 30 and the air inlet of the heat absorption chamber 4012. The return pipe 404 is connected to the air inlet of the bakelite pipe 30 and the air outlet of the heat absorption chamber 4012.

[0031] It should be noted that the air inlet of the heat absorption chamber 4012 is the common confluence of the ventilation pipe 402 and the guide pipe 403. Both the ventilation pipe 402 and the guide pipe 403 are connected to this air inlet of the heat absorption chamber 4012, rather than forming two independent air inlets on the heat absorption chamber 4012. Fresh nitrogen gas produced by the nitrogen generator reaches this air inlet through the ventilation pipe 402, and the return nitrogen gas discharged from the outlet of the bakelite pipe 30 also reaches this air inlet through the guide pipe 403. The two gases come into contact and mix at this air inlet before entering the heat absorption chamber 4012, and then enter the heat absorption chamber 4012 together.

[0032] The wire drawing machine annealing and anti-oxidation device provided in this embodiment of the application includes a nitrogen generator producing room temperature nitrogen gas, which is sent into the heat absorption chamber 4012 of the preheating box 401 via a vent pipe 402. Simultaneously, after the high-temperature wire passes through the annealing unit 10, it passes through the heat release chamber 4011 and then through the preheating box 401. The high-temperature residual heat carried by the wire is radiated through the wall of the heat release chamber 4011 to the heat absorption chamber 4012, heating the nitrogen gas inside. The preheated nitrogen gas is then sent through a return pipe 404 to the inlet of the bakelite pipe 30 and enters the anti-oxidation chamber, forming a protective atmosphere for the high-temperature wire passing through the bakelite pipe 30. The nitrogen gas in the anti-oxidation chamber flows back to the inlet of the heat absorption chamber 4012 via a guide pipe 403, forming a circulation path. After being preheated by the preheating unit 40, the wire enters the bakelite pipe 30, passes through the anti-oxidation chamber under nitrogen protection, and finally enters the cooling unit 20 for cooling.

[0033] Compared with existing technologies, by adding a preheating unit 40 between the annealing unit 10 and the bakelite pipe 30, the residual heat radiated outward when the high-temperature wire passes through the exothermic chamber 4011 is used to preheat the nitrogen flowing in the absorbent chamber 4012, making the nitrogen significantly warmer than room temperature before entering the bakelite pipe 30. This effectively reduces the temperature difference between the nitrogen and the high-temperature copper wire, avoids the thermal shock effect caused by room-temperature nitrogen directly impacting the high-temperature copper wire, eliminates lattice distortion and residual stress caused by rapid cooling of the copper crystal structure, and keeps key performance indicators such as elongation and conductivity of the copper wire stable after annealing, thus improving product consistency and yield.

[0034] Meanwhile, the preheating process requires no external energy input and makes full use of the waste heat from annealing, further reducing system energy consumption.

[0035] In some embodiments, see Figure 2 The preheating box 401 is also provided with a heat conduction cavity 4013, which is located between the heat absorption cavity 4012 and the heat release cavity 4011.

[0036] The preheating unit 40 also includes a phase change material 405 disposed in the heat conduction cavity 4013.

[0037] Optionally, phase change material 405 is a high-purity refined alkane phase change wax.

[0038] The high-temperature residual heat released when the wire passes through the heat release chamber 4011 is first conducted through the wall of the heat release chamber 4011 to the phase change material 405 in the heat conduction chamber 4013. When the temperature of the phase change material 405 reaches its melting point, the material begins to melt, absorbing and storing the residual heat of the wire; the heat is further conducted through the outer wall of the heat conduction chamber 4013 to the heat absorption chamber 4012, heating the nitrogen gas in the heat absorption chamber 4012. When the residual heat of the wire decreases, the phase change material 405 gradually solidifies, releasing the stored latent heat, continuing to maintain the heat supply to the heat absorption chamber 4012, and keeping the nitrogen preheating temperature stable.

[0039] A heat-conducting cavity 4013 filled with phase change material 405 is added between the heat absorption cavity 4012 and the heat release cavity 4011. Utilizing the characteristic of phase change material 405 to absorb or release a large amount of latent heat during the solid-liquid phase change process, a "peak-shaving and valley-filling" buffer is applied to the residual heat of the wire. When the heat brought in by the wire is excessive, the phase change material 405 melts and absorbs heat, storing the excess heat; when the heat of the wire is insufficient, the phase change material 405 solidifies and releases heat, continuously heating the nitrogen gas. This ensures that the nitrogen preheating temperature remains stable near the melting point of the phase change material 405 for a long time, significantly suppressing the nitrogen outlet temperature drift caused by fluctuations in the wire drawing machine's line speed, ensuring a constant nitrogen temperature entering the bakelite pipe 30, and further improving the stability of the copper wire's performance after annealing.

[0040] In some embodiments, see Figure 2The preheating unit 40 also includes a heat-conducting frame 406 disposed in the heat-conducting cavity 4013, and the heat-conducting frame 406 has a storage cavity 4062 for holding the phase change material 405.

[0041] Optionally, the thermally conductive skeleton 406 is a foamed copper skeleton.

[0042] After the heat dissipation chamber 4011 absorbs the residual heat from the wire, the heat is rapidly conducted to the heat-conducting frame 406. The frame, utilizing its high thermal conductivity, quickly transfers the heat to all parts of the phase change material 405 within the entire storage cavity 4062, allowing the phase change material 405 to be uniformly heated and melted. When nitrogen flows through the heat absorption chamber 4012, the wall of the heat absorption chamber 4012 absorbs heat from the heat-conducting frame 406, heating the nitrogen. The heat-conducting frame 406 acts as a "thermal bridge" between the walls of the heat dissipation chamber 4011 and the heat absorption chamber 4012, making heat transfer more efficient and uniform.

[0043] In some embodiments, see Figure 2 The inner wall of the storage cavity 4062 is provided with a diaphragm 4063, which divides the storage cavity 4062 into a phase change cavity 4064 and a gas cavity 4065. The phase change cavity 4064 is used to hold the phase change material 405, and the gas cavity 4065 is used to hold the gas.

[0044] The preheating unit 40 also includes a pressure sensor located in the air chamber 4065, an electrically controlled valve located in the return air pipe 404, and a control structure that is connected to the pressure sensor and the electrically controlled valve. The electrically controlled valve is used to control the opening degree of the return air pipe 404.

[0045] During the endothermic melting process, the phase change material 405 expands in volume, pushing the diaphragm 4063 to deform towards the gas chamber 4065, compressing the gas inside the gas chamber 4065 and increasing its pressure. The pressure sensor sends the current pressure value to the control structure. The control structure determines the degree of melting (heat storage) of the phase change material 405 based on the pressure value and adjusts the opening of the solenoid valve on the return gas pipe 404 accordingly: when the pressure increases (sufficient heat storage), the opening of the solenoid valve is increased, allowing more nitrogen to flow through the endothermic chamber 4012 to absorb heat; when the pressure decreases (insufficient heat storage), the opening of the solenoid valve is decreased, reducing the nitrogen flow rate to prevent nitrogen from flowing out of the endothermic chamber 4012 before it is fully preheated.

[0046] The control structure dynamically adjusts the opening of the solenoid valve on the return pipe 404 based on the feedback value of the pressure sensor, realizing the automatic adjustment logic of "the greater the heat storage of the phase change material 405 → the stronger the diaphragm 4063 pushes → the higher the pressure → the greater the valve opening → the increased nitrogen flow rate", so that the nitrogen intake volume is matched with the current heat storage of the phase change material 405 in real time, ensuring that the outlet nitrogen temperature is constant.

[0047] In some embodiments, the control structure is also used to acquire the linear speed signal and annealing current signal of the wire drawing machine host. The control structure calculates the estimated heat value of the current wire entering the heat release chamber 4011 based on the linear speed signal and annealing current signal, and generates a feedforward control signal based on the estimated heat value. The feedforward control signal is superimposed on the feedback signal of the air pressure sensor to jointly control the opening degree of the electric control valve.

[0048] The control structure reads the linear velocity signal (m / s) and annealing current signal (A) from the main control PLC of the wire drawing machine in real time, and calculates the estimated heat brought into the heat dissipation chamber 4011 by the current wire. The control structure converts this estimated value into a feedforward control signal and outputs it to the solenoid valve in advance to coarsely adjust the valve opening. At the same time, the current air pressure signal fed back by the air pressure sensor is processed by PID to generate a feedback control signal to finely adjust the valve opening. The feedforward signal and the feedback signal are superimposed in the control structure and jointly drive the solenoid valve to achieve precise and rapid adjustment of the nitrogen flow rate.

[0049] By introducing the linear speed signal and annealing current signal from the wire drawing machine, the control structure can calculate the heat estimate and generate a feedforward control signal in advance, before the heat change of the wire is actually conducted to the phase change material 405, thus adjusting the opening of the electronic control valve in advance. This feedforward-feedback composite control strategy overcomes the lag defect of temperature regulation relying solely on the feedback of the air pressure sensor, significantly improves the system's response speed to sudden operating conditions such as acceleration and deceleration of the wire drawing machine, and significantly enhances the system's anti-interference capability.

[0050] In some embodiments, the thermally conductive skeleton 406 has a porosity of 60%-90%.

[0051] This maximizes the heat exchange efficiency between the thermally conductive frame 406 and the phase change material 405, enabling the phase change material 405 to respond quickly to changes in the wire's heat and improving the device's dynamic thermal response performance.

[0052] In some embodiments, see Figure 2 The heat conduction cavity 4013 is set with multiple temperature zones along the direction of wire travel. The phase change material 405 in different temperature zones is different. The melting point of the phase change material 405 increases sequentially from the air inlet of the heat absorption cavity 4012 to the air outlet of the heat absorption cavity 4012.

[0053] It should be noted that a heat insulation ring 4061 is provided between the heat-conducting skeletons 406 in different temperature zones.

[0054] Low-temperature nitrogen flows in through the inlet of the heat absorption chamber 4012. It first passes through the first temperature zone with the lowest melting point, absorbing the heat released by the phase change material 405 in this temperature zone, and the temperature rises to the first level. Then it passes through the second temperature zone, the third temperature zone and so on with the melting point increasing step by step until the outlet. The temperature of the nitrogen is gradually raised to the highest preset temperature, rather than a sudden high temperature or constant temperature airflow. This reduces the thermal shock difference of nitrogen to different sections of the wire and further ensures the uniformity of the wire structure along its length.

[0055] In some embodiments, see Figure 2 The heat absorption chamber 4012 is provided with a traveling cylinder 50, which is rotatably connected to the preheating box 401. A spiral blade 501 is fixed to the outer periphery of the traveling cylinder 50.

[0056] When nitrogen flows through the spiral blades 501 on the outer periphery of the traveling cylinder 50, it generates a tangential impact force on the blades, causing the traveling cylinder 50 to rotate freely around its axis. The rotating traveling cylinder 50 drives the spiral blades 501 to continuously agitate the nitrogen in the heat absorption chamber 4012, changing it from a laminar flow state to a spiral propulsion turbulent state, thereby enhancing the convective heat transfer between the nitrogen and the wall of the heat absorption chamber 4012.

[0057] In some embodiments, see Figure 3 The sidewall of the spiral blade 501 is fitted with ball bearings 5011, which abut against the inner wall of the heat absorption box.

[0058] When nitrogen gas impacts the spiral blade 501 and drives the traveling cylinder 50 to rotate, the balls 5011 installed on the side wall of the spiral blade 501 roll along the inner wall of the heat absorption box, replacing sliding friction with rolling friction resistance, making the traveling cylinder 50 rotate more smoothly and responsively.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A wire drawing machine annealing anti-oxidation device, suitable for use between the annealing unit and the cooling unit, characterized in that, It includes a nitrogen generator, a bakelite pipe, and a preheating unit located between the annealing unit and the bakelite pipe, wherein the bakelite pipe is provided with an anti-oxidation chamber for the wire to pass through; The preheating unit includes: The preheating box has a heat release chamber for the wire to pass through, and the preheating box also has a heat absorption chamber, which is spaced around the outer periphery of the heat release chamber; A vent pipe connects the nitrogen generator and the heat absorption chamber to the air inlet. A vent pipe, connecting the outlet of the bakelite pipe and the inlet of the heat absorption chamber; and The return air pipe connects the air inlet of the bakelite pipe and the air outlet of the heat absorption chamber.

2. The wire drawing machine annealing and anti-oxidation device according to claim 1, characterized in that, The preheating box is also provided with a heat conduction cavity, which is located between the heat absorption cavity and the heat release cavity; The preheating unit also includes a phase change material disposed within the heat-conducting cavity.

3. The wire drawing machine annealing and anti-oxidation device according to claim 2, characterized in that, The preheating unit also includes a heat-conducting frame disposed in the heat-conducting cavity, and the heat-conducting frame has a storage cavity for holding the phase change material.

4. The wire drawing machine annealing and anti-oxidation device according to claim 3, characterized in that, The inner wall of the storage cavity is provided with a diaphragm, which divides the storage cavity into a phase change cavity and a gas cavity. The phase change cavity is used to hold the phase change material, and the gas cavity is used to hold the gas. The preheating unit also includes a pressure sensor located in the air chamber, an electrically controlled valve located in the return air pipe, and a control structure that is communicatively connected to the pressure sensor and the electrically controlled valve. The electrically controlled valve is used to control the opening degree of the return air pipe.

5. The wire drawing machine annealing and anti-oxidation device according to claim 4, characterized in that, The control structure is also used to acquire the linear speed signal and annealing current signal of the wire drawing machine host. The control structure calculates the estimated heat value of the current wire entering the heat release chamber based on the linear speed signal and the annealing current signal, and generates a feedforward control signal based on the estimated heat value. The feedforward control signal is superimposed on the feedback signal of the air pressure sensor to jointly control the opening degree of the electronically controlled valve.

6. The wire drawing machine annealing and anti-oxidation device according to claim 3, characterized in that, The porosity of the thermally conductive skeleton is 60%-90%.

7. The wire drawing machine annealing and anti-oxidation device according to claim 2, characterized in that, The heat-conducting cavity is sequentially set with multiple temperature zones along the direction of wire travel. The phase change materials in different temperature zones are different, and the melting point of the phase change materials increases sequentially from the air inlet to the air outlet of the heat-absorbing cavity.

8. The anti-oxidation device for annealing of a wire drawing machine according to claim 1, characterized in that, The heat absorption chamber is equipped with a traveling cylinder, which is rotatably connected to the preheating box, and a spiral blade is fixed to the outer periphery of the traveling cylinder.

9. The anti-oxidation device for annealing of a wire drawing machine according to claim 8, characterized in that, The helical blades are fitted with ball bearings on their sidewalls, and the ball bearings abut against the inner wall of the heat absorption box.

Images