Microwave plasma spheroidization device for micron-sized powder and application method

Abstract

The application relates to a microwave plasma spheroidization device for micron-level powder and an application method, and relates to the technical field of metal powder processing; the device comprises a machine body and a plasma exciter arranged at the top of the machine body; a feeding pipe is arranged at the top of the machine body; a material collecting tank is arranged at the bottom of the machine body; a reaction tank is arranged in communication between the machine body and the material collecting tank; a mounting frame is arranged in the reaction tank; a buffer assembly for slowing down the falling speed of powder is arranged on the mounting frame; a cooling assembly for assisting in cooling powder is arranged on the reaction tank; and the application has the effect of improving the cooling spheroidization quality of metal powder.

Description

Technical Field

[0001] This application relates to the field of metal powder processing technology, and in particular to a microwave plasma spheroidization device and application method for micron-sized powders. Background Technology

[0002] In recent years, with the continuous development of metal powder metallurgy and metal additive manufacturing (3D printing) technologies, especially in high-end application fields such as aerospace and medical, higher requirements have been put forward for the quality and particle size of metal powders.

[0003] Microwave plasma spheroidization technology utilizes microwave energy to excite gas to form plasma. The high-temperature environment of the plasma melts the surface (or the entirety) of irregular powder particles. The molten droplets shrink into spherical shapes due to surface tension, and then the spherical shape is fixed by rapid cooling, thereby obtaining powders with high sphericity and high flowability.

[0004] Regarding the aforementioned technologies, after the metal powder is melted by plasma, it falls directly into the spheroidizing device. This results in too short a time for the metal powder to cool and fix its spherical surface, which can easily affect the cooling and spheroidizing quality of the metal powder and reduce its sphericity and flowability. Therefore, improvements are needed. Summary of the Invention

[0005] To improve the cooling and spheroidizing quality of metal powders, this application provides a microwave plasma spheroidizing device and application method for micron-sized powders.

[0006] Firstly, this application provides a microwave plasma spheroidizing device for micron-sized powders, employing the following technical solution: A microwave plasma spheroidizing device for micron-sized powder includes a body and a plasma exciter disposed on the top of the body. A feed pipe is disposed on the top of the body, and a collection tank is disposed on the bottom of the body. A reaction tank is disposed between the body and the collection tank. A mounting frame is disposed inside the reaction tank, and a buffer component for slowing down the falling speed of the powder is disposed on the mounting frame. A cooling component for assisting in cooling the powder is disposed on the reaction tank.

[0007] By employing the above technical solution, the plasma exciter melts the powder supplied by the feed pipe. The molten powder then contracts into spherical droplets under surface tension. The buffer assembly applies upward airflow resistance to the falling molten powder, slowing its descent and extending its residence time within the reaction vessel. The cooling assembly creates a low-temperature environment within the reaction vessel, thoroughly cooling the slowly falling powder and allowing sufficient time for the spherical droplets to solidify and solidify. Through the coordinated operation of the buffer and cooling assemblies, the powder undergoes sufficient cooling within the reaction vessel before falling into the collection tank for collection. This avoids insufficient sphericity or adhesion caused by excessively rapid descent and inadequate cooling, thus improving the cooling and spheroidization quality of the metal powder.

[0008] Preferably, the buffer assembly includes an air duct, an air duct component, and a guide ring plate; the air duct is mounted on a mounting frame, with one end facing the plasma exciter, and several sets of ventilation holes are formed through the peripheral wall of the air duct; the air duct component is disposed inside the air duct to guide the airflow to blow the molten powder in the plasma exciter; the guide ring plate is disposed at the end of the air duct facing the plasma exciter, and the inner diameter of the guide ring plate facing the end of the machine body gradually decreases towards the machine body to concentrate the airflow inside the air duct; the outer diameter of the guide ring plate away from the end of the machine body gradually increases towards the direction away from the plasma exciter to guide the powder to flow to the inner peripheral wall of the reaction vessel.

[0009] By adopting the above technical solution, the air intake component generates an upward airflow inside the air intake duct. The airflow is drawn in from the bottom of the air intake duct and blown upward through the duct. The inner diameter of the upper end of the guide ring plate narrows, which converges and accelerates the airflow, enhancing the upward lifting force on the molten powder to disperse it and spread it in all directions. The outer diameter of the lower end of the guide ring plate expands, guiding the airflow carrying the powder outward, causing the powder to scatter and fall along the inner peripheral wall of the reaction tank, increasing the contact area and heat exchange distance between the powder and the inside of the reaction tank, and further extending the cooling path. In addition, the airflow inside the air intake duct is blown outward through the ventilation holes to apply a radial force along the air intake duct to the falling powder, prompting the powder to approach the inner wall of the reaction tank for heat exchange and further slowing down the falling speed of the powder.

[0010] Preferably, the mounting frame is provided with a rotating component for driving the air duct to rotate, and the mounting frame is provided with a shocking component for shocking the mounting frame.

[0011] By adopting the above technical solution, the rotating component drives the exhaust pipe to rotate, and the rotating exhaust pipe generates circumferential disturbance to the airflow, causing the airflow to form a rotating flow field inside the reaction vessel. The powder falls along a spiral path in the rotating airflow, further extending the residence time. In addition, the rotating exhaust pipe uses the rotating flow field to drive the powder to scatter and adhere to the inner wall of the reaction vessel for heat exchange, improving the cooling efficiency of the powder. The shock-absorbing component applies intermittent impact vibration to the mounting frame, shaking off the powder adhering to the surface of the mounting frame and exhaust pipe, preventing the powder from accumulating and affecting the smooth flow of air.

[0012] Preferably, the rotating assembly includes a fixed gear ring, a rotating gear, and a rotating motor; the air duct is rotatably connected to the mounting frame; the fixed gear ring is sleeved on the air duct, the rotating gear is rotatably mounted on the mounting frame, and the rotating gear and the fixed gear ring mesh with each other for transmission; the rotating motor is mounted on the mounting frame to drive the rotating gear to rotate.

[0013] By adopting the above technical solution, a rotating motor drives a rotating gear to rotate, and the rotating gear drives the exhaust pipe to rotate around its own axis through a fixed gear ring. The gear meshing transmission method has a precise transmission ratio, ensuring that the exhaust pipe rotates at a stable speed.

[0014] Preferably, the shock-absorbing assembly includes a fixed protrusion, a baffle cover, and shock-absorbing balls; the fixed protrusions are spaced apart on the mounting frame along the circumference of the air duct, the baffle cover is fitted over the end of the air duct facing the mounting frame to cover the rotating assembly; the shock-absorbing balls are spaced apart on the peripheral wall of the baffle cover along the circumference of the baffle cover to impact the fixed protrusions.

[0015] By adopting the above technical solution, the rotation of the exhaust pipe drives the baffle to rotate synchronously, and the shock balls on the baffle rotate with it. When the shock balls pass the fixed protrusion on the mounting frame, the shock balls strike the fixed protrusion and generate vibration. The vibration is transmitted to the exhaust pipe and other components through the mounting frame. The baffle covers the rotating assembly to prevent powder from entering the meshing gap of the rotating assembly and causing jamming.

[0016] Preferably, the cooling assembly includes a heat-conducting pipe, a mounting bracket, a water supply ring, a water supply pipe, a water outlet ring, and a water outlet pipe; the heat-conducting pipe passes through the inside of the reaction tank and extends spirally along the height direction of the reaction tank; the mounting bracket is located outside the reaction tank, and both the water supply ring and the water outlet ring are mounted on the mounting bracket; the water supply ring is located between the machine body and the reaction tank, and the water supply pipe is connected to the water supply ring, with one end of the water supply ring connected to the heat-conducting pipe; the water outlet ring is located between the machine body and the collection tank, and the water outlet pipe is connected to the water outlet ring, with the other end of the water outlet ring connected to the heat-conducting pipe.

[0017] By adopting the above technical solution, cooling water enters the water supply ring through the water supply pipe, and is distributed into each loop of the spiral heat-conducting pipe. It flows along the spiral path throughout the entire interior of the reaction tank, absorbing heat from the powder and gas inside, and then collects at the outlet ring before being discharged through the outlet pipe. The spiral extension of the heat-conducting pipe increases the heat exchange area and time between the cooling water and the internal thermal environment of the reaction tank, improving cooling efficiency and thus providing auxiliary cooling for the spheroidized powder.

[0018] Preferably, the water supply ring and the water outlet ring are rotatably connected to the end of the reaction tank, and the fixed frame is provided with a driving component to drive the reaction tank to rotate, and the rotation direction of the reaction tank is opposite to the rotation direction of the exhaust pipe.

[0019] By adopting the above technical solution, the driving component drives the entire reaction tank to rotate in the opposite direction to the exhaust pipe, generating reverse disturbance to the airflow inside the tank and enhancing convective heat transfer between the airflow and the inner wall of the reaction tank. Simultaneously, the centrifugal force generated by the rotation of the reaction tank throws the powder near the tank wall outwards, further dispersing the powder distribution and promoting uniform cooling; and the airflow in the opposite direction to the reaction tank and pipe causes the airflow to come into contact with the inner wall of the reaction tank, reducing powder adhesion to the inner wall and ensuring stable powder discharge.

[0020] Preferably, the bottom of the reaction vessel is provided with a sieve screen for screening powder, and an elastic element is provided between the bottom of the reaction vessel and the sieve screen to drive the sieve screen closer to the air duct by its own elastic force; the side wall of the sieve screen facing the air duct is provided with a number of positioning protrusions at intervals along the circumference of the sieve screen, and a rotating rod is provided at the bottom of the air duct, and a pressing rod is provided on the rotating rod for pressing and fixing the protrusions away from the air duct.

[0021] By adopting the above technical solution, the cooled powder falls onto the screening screen, and the powder that meets the particle size requirements passes through the screening screen and enters the collection tank. When the exhaust pipe rotates, it drives the pressing rod to rotate synchronously through the rotating rod. The pressing rod periodically presses the positioning protrusions on the screening screen, pushing the screening screen to move downward against the elastic force of the elastic element. When the pressing rod slides past the positioning protrusion, the elastic element pushes the screening screen upward to rebound, generating up-and-down vibration to shake the powder on the screening screen, preventing the powder from clogging the screening screen holes and improving screening efficiency. Furthermore, the upward vibration force of the screening screen promotes the upward movement of agglomerated powder that does not meet the particle size requirements. The rotating rod and pressing rod then crush the agglomerated powder, reducing the agglomeration of the powder.

[0022] Preferably, the collection tank is provided with a converging hopper inside, and the inner diameter of the converging hopper gradually decreases in the direction away from the reaction tank. The inner wall of the converging hopper is provided with a positioning frame, and the positioning frame is provided with a baffle hopper for passing through the converging hopper. A gap is left between the outer peripheral wall of the baffle hopper and the inner peripheral wall of the converging hopper for the powder to pass through, and the outer diameter of the baffle hopper gradually increases in the direction away from the reaction tank.

[0023] By adopting the above technical solution, the powder falls into the collection tank, first sliding down the conical inner wall of the closing hopper, then landing on the upper surface of the baffle hopper, and finally sliding down the conical outer wall of the baffle hopper to the bottom of the collection tank. The meandering channel formed by the baffle hopper and the closing hopper provides secondary buffering and deceleration for the powder, further extending the cooling time of the powder, while avoiding the accumulation and dust caused by the powder falling directly from a height; furthermore, the gap formed by the bottom-contracting closing hopper and the baffle hopper reduces the impact of the rising airflow generated by the buffer components on the powder inside the collection tank, ensuring stable collection of the powder.

[0024] Secondly, This application provides a method for using a microwave plasma spheroidizing device for micron-sized powders, comprising the following steps: Ignition: The plasma exciter ignites the plasma to form a microwave plasma torch; Feeding: The feed tube supplies the powder to be spheroidized to the microwave plasma torch body; Buffer: The buffer component slows down the falling speed of the molten powder; Cooling: The cooling components assist in cooling the powder falling inside the reaction vessel; Collection: The collection tank collects the spheroidized powder falling from inside the reaction tank.

[0025] In summary, this application includes at least one of the following beneficial technical effects: This application applies an upward airflow lifting force to the molten powder through a buffer component, which slows down the falling speed of the powder. Combined with the cooling component, a low-temperature environment is formed in the reaction vessel, which allows the powder to solidify and shape after sufficient cooling. This significantly prolongs the cooling and spheroidizing time of the powder and improves the sphericity and flowability of the metal powder. By combining the rotating component and the shock component, the air duct rotates to form a rotating flow field, causing the powder to fall along the spiral path. The shock ball hits the fixed protrusion to shake off the adhering powder, which not only extends the cooling path but also ensures the smooth flow of air. Automatic vibratory screening is achieved through the cooperation of the screening screen and the pressing rod, and the detour channel formed by the closing hopper and the baffle hopper decelerates the powder a second time, further improving the collection quality and cooling effect of the powder. Attached Figure Description

[0026] Figure 1This is a schematic diagram of the structure of a microwave plasma spheroidization device and application method for micron-sized powder according to an embodiment of this application.

[0027] Figure 2 It is a cross-sectional schematic diagram used to show the internal structure of the reaction vessel.

[0028] Figure 3 It is a cross-sectional schematic diagram used to illustrate the connection between the shock-absorbing components and the air duct.

[0029] Explanation of reference numerals in the attached figures: 1. Body; 11. Plasma exciter; 12. Feed pipe; 13. Collection tank; 2. Reaction vessel; 21. Mounting frame; 22. Screening screen; 221. Positioning protrusion; 23. Elastic component; 3. Buffer assembly; 31. Air duct; 311. Ventilation hole; 312. Rotating rod; 313. Pressing rod; 32. Air duct component; 33. Guide ring plate; 4. Cooling assembly; 41. Heat conduction pipe; 42. Fixing frame; 421. Driving component; 43. Water supply ring; 44. Water supply pipe; 45. Water outlet ring; 46. Water outlet pipe; 5. Rotating assembly; 51. Fixed gear ring; 52. Rotating gear; 53. Rotating motor; 6. Vibration assembly; 61. Fixed protrusion; 62. Material baffle; 63. Vibration ball; 7. Closing hopper; 71. Positioning frame; 72. Material baffle hopper. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0031] This application discloses a microwave plasma spheroidizing device and application method for micron-sized powders, which can be used to improve the cooling spheroidizing quality of metal powders.

[0032] Reference Figure 1 and Figure 2 A microwave plasma spheroidizing device for micron-sized powder includes a body 1 and a plasma exciter 11 mounted on top of the body 1. The plasma exciter 11 is used to excite the working gas to form a plasma torch using microwave energy. A feed pipe 12 is also mounted on top of the body 1, with the outlet of the feed pipe 12 facing the plasma torch area. A collection tank 13 is connected to the bottom of the body 1.

[0033] Reference Figure 1 and Figure 2A reaction tank 2 is installed between the machine body 1 and the collection tank 13. The reaction tank 2 is a hollow cylindrical structure with openings at both ends. One end of the reaction tank 2 is connected to the bottom of the machine body 1, and the inner diameter of the reaction tank 2 gradually decreases towards the end of the machine body 1. The other end of the reaction tank 2 is connected to the top of the collection tank 13, and the inner diameter of the reaction tank 2 gradually decreases towards the end of the collection tank 13, so that the powder can be close to the inner wall of the reaction tank 2 for heat exchange and cooling during the falling process. A mounting frame 21 is fixedly installed inside the reaction tank 2, and a buffer assembly 3 is installed on the mounting frame 21. A cooling assembly 4 is installed on the reaction tank 2.

[0034] Reference Figure 1 and Figure 2 The buffer assembly 3 includes an air duct 31, an air duct component 32, and a guide ring plate 33. The air duct 31 is rotatably mounted on the mounting frame 21 via bearings, with its upper end facing the plasma exciter 11. Multiple sets of ventilation holes 311 are formed through the peripheral wall of the air duct 31, evenly distributed along its circumference and axial direction. The air duct component 32 is fixedly installed inside the air duct 31; specifically, the air duct component 32 is an air duct fan that guides airflow from the bottom of the air duct 31 and blows it upwards during operation.

[0035] Reference Figure 1 and Figure 2 The guide ring plate 33 is fixedly installed at the end of the air duct 31 facing the plasma exciter 11. The inner diameter of the upper port of the guide ring plate 33 gradually decreases from bottom to top, forming a tapered opening. The outer diameter of the lower port of the guide ring plate 33 gradually increases from top to bottom, forming a tapered flared opening, to help the powder adhere to the inner circumferential wall of the upper part of the reaction vessel 2.

[0036] Reference Figure 2 and Figure 3 A rotating assembly 5 is mounted on the mounting bracket 21. The rotating assembly 5 includes a fixed gear ring 51, a rotating gear 52, and a rotating motor 53. The fixed gear ring 51 is fixedly sleeved on the outer peripheral wall of the air duct 31. The rotating gear 52 is rotatably mounted on the mounting bracket 21 via bearings and meshes with the fixed gear ring 51 for transmission. The rotating motor 53 is fixedly mounted on the mounting bracket 21, and the output shaft of the rotating motor 53 is connected to the rotating gear 52 for transmission, so as to drive the rotating gear 52 to rotate the fixed gear ring 51 and the air duct 31.

[0037] Reference Figure 2 and Figure 3A vibration assembly 6 is mounted on the mounting frame 21. The vibration assembly 6 includes a fixed protrusion 61, a baffle 62, and vibration balls 63. The fixed protrusions 61 are fixedly fixed to the mounting frame 21 at intervals along the circumference of the air duct 31. The baffle 62 is fixedly sleeved on the lower end of the air duct 31 facing the mounting frame 21 and covers the outside of the rotating assembly 5. The vibration balls 63 are fixedly fixed to the outer peripheral wall of the baffle 62 at intervals along the circumference of the baffle 62 to intermittently impact the fixed protrusions 61, thereby causing the mounting frame 21, the baffle 62, and the air duct 31 to vibrate, thus reducing the adhesion of powder.

[0038] Reference Figure 1 and Figure 2 The cooling assembly 4 includes a heat pipe 41, a mounting bracket 42, a water supply ring 43, a water supply pipe 44, a water outlet ring 45, and a water outlet pipe 46. The heat pipe 41 is installed inside the reaction tank 2 and extends spirally along the height of the reaction tank 2. The mounting bracket 42 is installed outside the reaction tank 2, and both the water supply ring 43 and the water outlet ring 45 are fixedly installed on the mounting bracket 42. The water supply ring 43 is located at the connection between the machine body 1 and the reaction tank 2. The water supply ring 43 is rotatably connected to the end of the reaction tank 2 via a rotary joint, and the interior of the water supply ring 43 is connected to the upper end of the heat pipe 41. The water supply pipe 44 is connected to the water supply ring 43 to supply coolant to the interior of the water supply ring 43. The water outlet ring 45 is located at the connection between the reaction tank 2 and the collection tank 13. The water outlet ring 45 is rotatably connected to the end of the reaction tank 2 via a rotary joint, and the interior of the water outlet ring 45 is connected to the lower end of the heat pipe 41. The outlet pipe 46 is connected to the outlet ring 45 for discharging the coolant after heat exchange.

[0039] Reference Figure 1 and Figure 2 A drive component 421 is installed on the fixed frame 42. In this embodiment, the drive component 421 includes a gear structure driven by a motor to drive the reaction vessel 2 to rotate around its own axis, and the rotation direction of the reaction vessel 2 is set to be opposite to the rotation direction of the duct 31.

[0040] Reference Figure 2 and Figure 3 A screen 22 is installed at the bottom of the reaction vessel 2, and the screen 22 is horizontally positioned. An elastic element 23 is installed between the bottom of the reaction vessel 2 and the bottom wall of the screen 22. Specifically, the elastic element 23 is a compression spring with an upward elastic force, pushing the screen 22 closer to the air duct 31. Multiple sets of positioning protrusions 221 are fixedly fixed circumferentially on the upper surface of the screen 22. A rotating rod 312 is fixedly connected to the bottom of the air duct 31 via a bracket, and the rotating rod 312 rotates synchronously with the air duct 31. A pressing rod 313 is fixedly installed on the rotating rod 312. The end of the pressing rod 313 is used to indirectly contact the positioning protrusions 221 and press the positioning protrusions 221 downward.

[0041] Reference Figure 2 and Figure 3 The collecting tank 13 has a tapering hopper 7 installed inside. The inner diameter of the tapering hopper 7 gradually decreases from top to bottom, forming an inverted cone shape. A positioning frame 71 is fixedly installed on the inner wall of the tapering hopper 7, and a baffle hopper 72 is fixedly installed on the positioning frame 71. The baffle hopper 72 passes through the bottom port of the tapering hopper 7, and the outer diameter of the baffle hopper 72 gradually increases from top to bottom, forming a regular cone shape. An annular gap is left between the outer peripheral wall of the baffle hopper 72 and the inner peripheral wall of the bottom port of the tapering hopper 7 for the powder to pass through.

[0042] The implementation principle of the microwave plasma spheroidizing device for micron-sized powder in this application embodiment is as follows: The plasma exciter 11 is ignited to form a plasma torch. The feed pipe 12 supplies metal powder to the torch area. The powder melts at high temperature and shrinks into spherical droplets under the action of surface tension. The spherical droplets fall under the action of gravity and enter the reaction tank 2 area.

[0043] The air intake component 32 generates an upward airflow inside the air intake pipe 31. The airflow is drawn in from the bottom of the air intake pipe 31 and blown upward. After being converged and accelerated at the upper port of the guide ring plate 33, it applies an upward lifting force to the falling droplets, blowing the molten powder apart and spreading it in all directions.

[0044] The lower end of the guide ring plate 33 guides the airflow carrying the powder outward, causing the powder to scatter and fall along the inner circumferential wall of the reaction tank 2. Simultaneously, the airflow inside the duct 31 is blown outward through the ventilation holes 311, applying a radial force along the duct 31 to the falling powder. This, combined with the rotation of the duct 31 by the rotating component 5, causes the airflow from the ventilation holes 311 to push the powder closer to the inner wall of the reaction tank 2 for heat exchange, further slowing the powder's descent.

[0045] The rotating motor 53 drives the rotating gear 52 and the fixed gear ring 51 to rotate the exhaust pipe 31. The rotating exhaust pipe 31 generates circumferential disturbance to the airflow, creating a rotating flow field within the reaction vessel 2. The powder falls along a spiral path in the rotating airflow, further extending the residence time. The rotating flow field causes the powder to disperse and adhere to the inner wall of the reaction vessel 2 for heat exchange. The driving component 421 drives the reaction vessel 2 to rotate in the opposite direction, generating reverse disturbance to the airflow inside the vessel, enhancing the convective heat exchange between the airflow and the inner wall of the reaction vessel 2. The opposite rotation of the reaction vessel 2 and the airflow inside the vessel cause the airflow to come into contact with the inner wall of the reaction vessel 2, reducing the adhesion of powder to the inner wall of the reaction vessel 2.

[0046] Cooling water enters the water supply ring 43 through the water supply pipe 44, and is distributed into each loop of the spiral heat-conducting pipe 41. It flows along the spiral path through the entire interior of the reaction vessel 2, absorbing heat from the powder and gas inside, and then collects at the outlet ring 45 before being discharged through the outlet pipe 46. During its slow descent, the spherical droplets continuously exchange heat with the heat-conducting pipe 41 and the inner wall of the reaction vessel 2, fully solidifying and solidifying into spherical powder.

[0047] After passing through the screening screen 22, the powder falls into the collection tank 13. It first slides down the conical inner wall of the converging hopper 7, then lands on the upper surface of the baffle hopper 72, and slides down the conical outer wall of the baffle hopper 72 to the bottom of the collection tank 13. The meandering channel formed by the baffle hopper 72 and the converging hopper 7 provides secondary buffering and deceleration for the powder, further extending its cooling time. The constricted structure at the bottom of the converging hopper 7 reduces the impact of the rising airflow generated by the induced draft fan 32 on the powder inside the collection tank 13.

[0048] This application also discloses a method for using a microwave plasma spheroidizing device for micron-sized powders, comprising the following steps: Ignition: Plasma excier 11 performs plasma ignition to form a microwave plasma torch.

[0049] Feeding: Feeding pipe 12 feeds the powder to be spheroidized to the microwave plasma torch body.

[0050] Buffer: The air duct 32 generates an upward airflow in the air duct 31, which converges at the upper end of the guide ring plate 33 and applies a lifting force to the molten powder, blowing the powder outward and spreading it in all directions; the ventilation hole 311 blows air outward and applies a radial force to the powder; the rotating component 5 drives the air duct 31 to rotate and form a rotating flow field, and the powder falls along the spiral path and scatters close to the inner wall of the reaction tank 2 for heat exchange.

[0051] Cooling: Cooling water flows through the spiral heat pipe 41 to absorb heat from the reaction vessel 2; the driving component 421 drives the reaction vessel 2 to rotate in the opposite direction, enhancing convective heat transfer and reducing powder adhesion.

[0052] Collection: The screening screen 22 vibrates and screens the powder, and the pressing rod 313 and rotating rod 312 crush the powder. The qualified powder passes through the screening screen 22 and falls into the bottom of the collection tank 13 through the meandering channel formed by the closing hopper 7 and the baffle hopper 72.

[0053] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A microwave plasma spheroidizing device for micron-sized powder, comprising a body (1) and a plasma exciter (11) disposed on the top of the body (1), wherein a feed pipe (12) is disposed on the top of the body (1) and a collection tank (13) is disposed on the bottom of the body (1); characterized in that: A reaction tank (2) is connected between the machine body (1) and the collection tank (13). A mounting frame (21) is provided inside the reaction tank (2). A buffer component (3) for slowing down the falling speed of the powder is provided on the mounting frame (21). A cooling component (4) for assisting in cooling the powder is provided on the reaction tank (2).

2. The microwave plasma spheroidizing device for micron-sized powder according to claim 1, characterized in that: The buffer assembly (3) includes an air duct (31), an air duct component (32), and a guide ring plate (33); the air duct (31) is mounted on the mounting frame (21), one end of the air duct (31) faces the plasma exciter (11), and several sets of ventilation holes (311) are opened through the peripheral wall of the air duct (31); the air duct component (32) is located inside the air duct (31) to guide the airflow to blow the molten powder of the plasma exciter (11); The guide ring plate (33) is provided with an air duct (31) facing the end of the plasma exciter (11). The inner diameter of the guide ring plate (33) facing the end of the machine body (1) gradually decreases towards the machine body (1) to gather the airflow inside the air duct (31). The outer diameter of the guide ring plate (33) away from the end of the machine body (1) gradually increases towards the end of the plasma exciter (11) to guide the powder to flow to the inner circumferential wall of the reaction vessel (2).

3. The microwave plasma spheroidizing device for micron-sized powder according to claim 2, characterized in that: The mounting bracket (21) is provided with a rotating assembly (5) for driving the air duct (31) to rotate, and the mounting bracket (21) is provided with a shocking assembly (6) for shocking the mounting bracket (21).

4. The microwave plasma spheroidizing device for micron-sized powder according to claim 3, characterized in that: The rotating assembly (5) includes a fixed gear ring (51), a rotating gear (52), and a rotating motor (53); the air duct (31) is rotatably connected to the mounting frame (21); the fixed gear ring (51) is sleeved on the air duct (31), the rotating gear (52) is rotatably mounted on the mounting frame (21), and the rotating gear (52) and the fixed gear ring (51) mesh with each other for transmission; the rotating motor (53) is mounted on the mounting frame (21) to drive the rotating gear (52) to rotate.

5. The microwave plasma spheroidizing device for micron-sized powder according to claim 3, characterized in that: The shock-absorbing assembly (6) includes a fixed protrusion (61), a baffle (62), and a shock-absorbing ball (63); the fixed protrusion (61) is spaced along the circumference of the air duct (31) on the mounting frame (21), and the baffle (62) is fitted onto the end of the air duct (31) facing the mounting frame (21) to cover the rotating assembly (5); the shock-absorbing ball (63) is spaced along the circumference of the baffle (62) on the peripheral wall of the baffle (62) to impact the fixed protrusion (61).

6. The microwave plasma spheroidizing device for micron-sized powder according to claim 3, characterized in that: The cooling assembly (4) includes a heat pipe (41), a mounting bracket (42), a water supply ring (43), a water supply pipe (44), a water outlet ring (45), and a water outlet pipe (46); the heat pipe (41) is inserted inside the reaction vessel (2), and the heat pipe (41) extends spirally along the height direction of the reaction vessel (2); the mounting bracket (42) is located outside the reaction vessel (2), and the water supply ring (43) and the water outlet ring (45) are both located on the mounting bracket. The water supply ring (43) is located between the machine body (1) and the reaction tank (2), and the water supply pipe (44) is connected to the water supply ring (43), and the water supply ring (43) is connected to one end of the heat conduction pipe (41); the water outlet ring (45) is located between the machine body (1) and the collection tank (13), and the water outlet pipe (46) is connected to the water outlet ring (45), and the water outlet ring (45) is connected to the other end of the heat conduction pipe (41).

7. The microwave plasma spheroidizing device for micron-sized powder according to claim 6, characterized in that: The water supply ring (43) and the water outlet ring (45) are rotatably connected to the end of the reaction tank (2), and a driving component (421) is provided on the fixed frame (42) to drive the reaction tank (2) to rotate, and the rotation direction of the reaction tank (2) is opposite to the rotation direction of the air duct (31).

8. The microwave plasma spheroidizing device for micron-sized powder according to claim 3, characterized in that: The bottom of the reaction vessel (2) is provided with a sieve screen (22) for screening powder. An elastic element (23) is provided between the bottom of the reaction vessel (2) and the sieve screen (22) to drive the sieve screen (22) closer to the air duct (31) by its own elastic force. The side wall of the sieve screen (22) facing the air duct (31) is provided with a number of positioning protrusions (221) at intervals along the circumference of the sieve screen (22). The bottom of the air duct (31) is provided with a rotating rod (312). The rotating rod (312) is provided with a pressing rod (313) for pressing and fixing the protrusions (61) away from the air duct (31).

9. The microwave plasma spheroidizing device for micron-sized powder according to claim 1, characterized in that: The collection tank (13) is provided with a converging hopper (7) inside, and the inner diameter of the converging hopper (7) gradually decreases in the direction away from the reaction tank (2). The inner wall of the converging hopper (7) is provided with a positioning frame (71), and the positioning frame (71) is provided with a baffle hopper (72) for passing through the converging hopper (7). A gap is left between the outer peripheral wall of the baffle hopper (72) and the inner peripheral wall of the converging hopper (7) for the powder to pass through, and the outer diameter of the baffle hopper (72) gradually increases in the direction away from the reaction tank (2).

10. A method for using a microwave plasma spheroidizing device employing micron-sized powder as described in any one of claims 1-9, characterized in that: Includes the following steps: Ignition: The plasma exciter (11) performs plasma ignition to form a microwave plasma torch; Feeding: The feeding pipe (12) feeds the powder to be spheroidized toward the microwave plasma torch body; Buffer: The buffer component (3) slows down the falling speed of the molten powder; Cooling: The cooling component (4) assists in cooling the powder falling inside the reaction vessel (2); Collection: The collection tank (13) collects the spheroidized powder falling inside the reaction tank (2).

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