Reverse powder feeding plasma spheroidizing radio frequency reaction torch capable of secondary reaction

Abstract

The invention discloses a reverse powder feeding plasma spheroidizing radio frequency reaction torch capable of secondary reaction, and relates to the field of plasma spheroidizing metal powder preparation.According to the technical scheme, the reverse powder feeding plasma spheroidizing radio frequency reaction torch comprises a reaction torch body, the reaction torch body comprises a vertically-through reaction cavity, and the middle section of the reaction cavity is of a cambered surface structure with the larger circle diameter; an inductance coil is arranged on the side wall of the middle section of the reaction cavity; an air supply pipe is arranged at the upper section of the reaction torch; and a powder feeding pipe is arranged at the lower end of the reaction cavity. The size of the inner diameter of the wall is enlarged in the middle of the reaction torch, the temperature is transversely concentrated in the middle, and the powder feeding pipe is mounted at the bottom, so that irregular metal powder can be subjected to secondary plasma spheroidizing reaction, the powder preparation efficiency is greatly improved, impurities on spherical powder are removed to a greater extent, and the powder quality is improved.

Description

Technical Field

[0001] This invention relates to the field of plasma spheroidization of metal powder, and in particular to a reverse-feeding plasma spheroidization radio frequency reaction torch capable of secondary reactions. Background Technology

[0002] In recent years, with the vigorous development of high technology and the urgent need for new nanomaterials and new preparation processes, the market demand for new and high-quality metal powder materials for additive manufacturing will show a rapid growth trend. It is imperative to strengthen the independent research and development and independent innovation of new and high-quality additive manufacturing metal materials, and the research and application of plasma chemistry are receiving increasing attention.

[0003] Among the many plasma powder making technologies, plasma spheroidizing powder technology (PS) has advantages such as high-quality powder, narrow particle size distribution, high yield and efficiency, good chemical purity and applicability to a variety of metals. Compared with other powder making technologies, it performs best in spheroidizing high-melting-point fine powders, and is therefore the most suitable spheroidizing technology for producing powders for additive manufacturing.

[0004] As a core component of plasma spheroidization equipment, the radio frequency (RF) plasma reaction torch directly affects the performance and lifespan of the equipment. Its key technologies include the design of the RF plasma reaction torch, the distribution of the temperature field within the torch, and the high-temperature reaction characteristics of the plasma. The RF plasma reaction torch is the core component of powder spheroidization, transferring energy to the gas through inductive coupling to generate high-temperature plasma for spheroidizing metal powders. However, during the powder spheroidization process, fine particles may still be present on the powder surface, leading to low powder production efficiency and poor powder quality. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a reverse-feeding plasma spheroidizing radio frequency reaction torch capable of secondary reaction. This design enlarges the inner diameter of the torch wall in the middle section, concentrating the temperature laterally in the center. The powder feeding tube is installed at the bottom, enabling irregular metal powders to undergo a secondary plasma spheroidizing reaction, significantly improving powder production efficiency, removing impurities from the spherical powder to a greater extent, and enhancing powder quality.

[0006] The technical solution adopted by this invention to solve its technical problem is: a reverse-feeding plasma spheroidizing radio frequency reaction torch capable of secondary reaction, comprising a reaction torch body, The reaction torch body includes a reaction chamber that runs vertically through the top and bottom. The middle section of the reaction chamber has an arc surface structure with a larger diameter. An inductor coil is provided on the side wall of the middle section of the reaction chamber. The upper section of the reaction torch is provided with a gas supply pipe; the lower end of the reaction chamber is provided with a powder supply pipe.

[0007] Preferably, the upper and lower sections of the reaction chamber are cylindrical structures.

[0008] Preferably, the middle section of the reaction chamber is cylindrical, and the two ends of the cylinder are tapered to transition to the upper and lower sections of the reaction chamber.

[0009] Preferably, the upper and lower sections of the reaction chamber have a radius of 30 cm, and the middle section of the reaction chamber has a maximum radius of 46-54 mm.

[0010] Preferably, the middle section of the reaction chamber has an elliptical structure.

[0011] Preferably, the upper and lower sections of the reaction chamber have a radius of 30 cm, and the middle section of the reaction chamber has a maximum radius of 60-64 mm.

[0012] Preferably, the gas delivery pipe includes a hydrogen gas delivery pipe and an ammonia gas delivery pipe.

[0013] Preferably, the powder feeding pipe is made of quartz material.

[0014] Preferably, the powder feeding pipe uses an inert gas pneumatic feeding system, and the inert gas is either argon or helium.

[0015] Preferably, the inductor coil comprises three coils spaced 29mm apart vertically.

[0016] Advantages of this invention: This design enlarges the inner wall size of the reaction chamber with coils in the middle section, causing a change in temperature distribution. This concentrates the high-temperature region in the middle section of the reaction chamber with coils, reducing energy loss. The arc-shaped structure of the middle section of the reaction chamber also makes the stress distribution within the inner diameter of the wall more uniform. The powder feeding pipe adopts a bottom-mounted method, which allows irregular metal powders to undergo a secondary plasma spheroidization reaction, greatly improving powder production efficiency, removing impurities from spherical powders to a greater extent, and improving powder quality. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only two of the drawings in this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a simulation diagram of the temperature distribution inside the reaction torch in Embodiment 1 of the present invention; Figure 2 This is a simulation diagram of the temperature distribution inside the reaction torch in Embodiment 2 of the present invention; Detailed Implementation

[0019] To enhance understanding of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. These embodiments are only used to explain the invention and do not limit the scope of protection of the invention. Example

[0020] like Figure 1 As shown, a reverse-feeding plasma spheroidizing radio frequency reaction torch capable of secondary reactions includes a torch body. The reaction torch body includes a reaction chamber that runs vertically through the top and bottom. The middle section of the reaction chamber has an arc surface structure with a larger diameter. An inductor coil is provided on the side wall of the middle section of the reaction chamber. The upper section of the reaction torch is provided with a gas supply pipe; the lower end of the reaction chamber is provided with a powder supply pipe.

[0021] The upper and lower sections of the reaction chamber are both cylindrical structures.

[0022] The middle section of the reaction chamber is cylindrical, and the two ends of the cylinder are tapered to transition to the upper and lower sections of the reaction chamber.

[0023] The upper and lower sections of the reaction chamber have a radius of 30 cm, and the middle section of the reaction chamber has a maximum radius of 46-54 mm.

[0024] The gas supply pipes include hydrogen gas supply pipes and ammonia gas supply pipes.

[0025] The powder feeding pipe is made of quartz material.

[0026] The powder feeding pipe uses an inert gas pneumatic feeding system, and the inert gas is either argon or helium.

[0027] The inductor coil comprises three coils spaced 29 mm apart vertically. Since simulation results show that the number of coils does not affect the temperature distribution within the reaction torch, three coils are more suitable to reduce costs. Example

[0028] Compared to Example 1, this example also includes the following feature: the middle section of the reaction chamber adopts an elliptical structure.

[0029] The upper and lower sections of the reaction chamber have a radius of 30 cm, and the middle section of the reaction chamber has a maximum radius of 60-64 mm.

[0030] Advantages of this invention: This design enlarges the inner wall size of the reaction chamber with coils in the middle section, causing a change in temperature distribution. This concentrates the high-temperature region in the middle section of the reaction chamber with coils, reducing energy loss. The arc-shaped structure of the middle section of the reaction chamber also makes the stress distribution within the inner diameter of the wall more uniform. The powder feeding pipe adopts a bottom-mounted method, which allows irregular metal powders to undergo a secondary plasma spheroidization reaction, greatly improving powder production efficiency, removing impurities from spherical powders to a greater extent, and improving powder quality.

[0031] This solution, which uses bottom-reverse powder feeding, has the following specific advantages: 1. Optimize powder heating efficiency Extend residence time: When the powder enters the high-temperature plasma zone from the bottom in the opposite direction, it needs to rise against the airflow to extend its residence time in the high-temperature zone, thereby promoting full melting and uniform heating.

[0032] Enhanced path controllability: Powder gradually enters the high-temperature core from the low-temperature zone, avoiding extreme problems such as powder "overburning" or "unmelting" in top powder feeding, thus improving thermal efficiency.

[0033] 2. Improve material utilization rate Reduce powder scattering: In traditional top-feeding systems, unmelted powder is easily blown away by high-speed plasma flow, leading to material waste (loss rate can reach over 30%). Bottom-feeding systems, through the combined effect of reverse airflow and gravity, can significantly reduce scattering losses, increasing material utilization to over 85%.

[0034] Optimized directional deposition: Bottom-feed powder makes it easier to form a "bottom-up" deposition path on the workpiece surface, which is especially suitable for coating complex curved surfaces or internal cavities (such as the inner wall of turbine blades) and reduces powder escape.

[0035] 3. Improve coating / cladding quality Improved uniformity: Bottom powder feeding makes the powder distribution more compatible with the plasma flow field, reducing local accumulation or porosity, and improving coating density (experiments show that porosity can be reduced to <2%).

[0036] Reduced unmelted particles: Fully heated powder can reduce the proportion of unmelted particles in the coating and improve the bonding strength (e.g., bonding strength is increased by 20%-30% in HVOF spraying).

[0037] 4. Adaptable to complex geometries No obstruction of vision: Bottom powder feeding eliminates the need to project powder from above the workpiece, avoiding the "blind spot" problem of traditional top powder feeding when processing deep grooves, inner holes, or overhanging structures, thus broadening the applicability of the process.

[0038] Multi-axis collaborative capability: In robot-assisted processing, the bottom powder feeding system can flexibly cooperate with multi-degree-of-freedom robotic arms to achieve high-precision manufacturing of complex three-dimensional structures.

[0039] 5. Enhance process stability Reduced plasma interference: The airflow direction of the reverse-feeding powder is opposite to the main plasma flow direction, which reduces the disturbance to the stability of the plasma torch and reduces arc fluctuation (experiments show that the voltage fluctuation amplitude is reduced by 15%-20%).

[0040] Powder-airflow coordinated control: By utilizing the counteracting effect of the reverse carrier gas and plasma flow, precise control of the powder trajectory can be achieved, reducing the sensitivity to process parameters.

[0041] 6. Energy-saving and environmental protection potential Improved energy efficiency: Sufficient heating and reduced scattering can reduce energy consumption per unit mass of powder. Experimental data shows that energy consumption can be reduced by 10%-15%.

[0042] Reduced dust emissions: Enclosed bottom dust feeding systems are easier to integrate with dust recovery devices, reducing particulate matter pollution in the working environment.

[0043] 7. Advantages in special scenarios Gravity-assisted deposition: In microgravity or vacuum environments (such as space manufacturing), bottom powder feeding can achieve stable transport by means of inertial force, breaking through the limitations of traditional powder feeding that relies on gravity.

[0044] Processing of high melting point materials: For high melting point materials such as tungsten and silicon carbide, the bottom-feeding gradual heating mode can avoid instantaneous overheating and volatilization of the material.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A reverse-feeding plasma spheroidizing radio frequency reaction torch capable of secondary reactions, characterized in that, Including the reaction torch body, The reaction torch body includes a reaction chamber that runs vertically through the top and bottom. The middle section of the reaction chamber has an arc surface structure with a larger diameter. An inductor coil is provided on the side wall of the middle section of the reaction chamber. The upper section of the reaction torch is provided with a gas supply pipe; the lower end of the reaction chamber is provided with a powder supply pipe.

2. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 1, characterized in that: The upper and lower sections of the reaction chamber are both cylindrical structures.

3. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 2, characterized in that: The middle section of the reaction chamber is cylindrical, and the two ends of the cylinder are tapered to transition to the upper and lower sections of the reaction chamber.

4. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 3, characterized in that: The upper and lower sections of the reaction chamber have a radius of 30 cm, and the middle section of the reaction chamber has a maximum radius of 46-54 mm.

5. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 2, characterized in that: The middle section of the reaction chamber has an elliptical structure.

6. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 5, characterized in that: The upper and lower sections of the reaction chamber have a radius of 30 cm, and the middle section of the reaction chamber has a maximum radius of 60-64 mm.

7. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 1, characterized in that: The gas supply pipes include hydrogen gas supply pipes and ammonia gas supply pipes.

8. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 1, characterized in that: The powder feeding pipe is made of quartz material.

9. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 1, characterized in that: The powder feeding pipe uses an inert gas pneumatic feeding system, and the inert gas is either argon or helium.

10. The reverse-feeding powder-spheroidizing radio frequency reaction torch capable of secondary reaction according to claim 1, characterized in that: The inductor coil comprises three coils spaced 29mm apart vertically.

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