A method for controlling the preparation of micron-sized spheroidized powders or nanopowders

Abstract

This invention discloses a method for controlling the preparation of micron-sized spheroidized powder or nano-powder. The controller opens the valves and / or switches between the gas supply device and the preparation device, and controls the vacuum pump to evacuate both the gas supply device and the preparation device. The controller controls the vacuum pump to adjust the gas pressure of each component in the gas supply device. The gas supply device fills the preparation device with working gas. The valves and / or switches on the cooling pipe connecting the cooling device and the preparation device are opened. The controller adjusts the gas pressure of each component in the gas supply device and the preparation device using a PID controller. The controller controls the flow of material within the preparation device under the blowing of the working gas to prepare micron-sized spheroidized powder or nano-powder. The vacuum pump evacuates the collection device. The collection device collects the powder in the preparation device. The working gas in the preparation device is filtered and returned to the gas supply device. The internal airflow pressure required by each component of this invention can be stably adjusted.

Description

Technical Field

[0001] This invention relates to the field of powder making equipment technology, and in particular to a method for controlling the preparation of micron-sized spherical powders or nano-powders. Background Technology

[0002] Micron-sized or nano-sized powders are mainly used in additive manufacturing, metal injection molding, and thermal spraying. Plasma spheroidization is one of the current methods for preparing micron-sized or nano-sized powders using plasma. In a high-temperature environment, the working gas sends the powder into a high-temperature plasma, where the powder particles melt rapidly and condense into spheres under surface tension. After cooling, they solidify into spherical powders with good sphericity. There is no pollution from electrode evaporation, and the prepared micron-sized or nano-sized powders have uniform composition and good flowability.

[0003] Existing systems for preparing micron-sized or nano-sized powders using plasma spheroidization involve numerous devices, each requiring a gas flow field. For example, patent CN113134618A discloses a plasma preparation device for metal-based ceramic 3D printing composite powders. This device uses a high-pressure nitrogen cylinder group connected to a high-pressure precision ceramic powder feeder to deliver material, and employs a central high-pressure argon cylinder, side high-pressure argon cylinders, and a high-pressure argon cylinder to supply working gas to a high-frequency induction plasma generator. The method of directly supplying gas through gas cylinders is inconvenient for regulating the working gas pressure of the entire preparation system, and the gas is directly vented and cannot be recycled. The device for preparing ultrafine pure metal powder disclosed in CN108788172B is equipped with a gas supply station and a gas mixing tank. Although it can achieve gas recycling, the gas mixing tank only supplies gas to the plasma gun and the powder preparation chamber in two ways. It cannot accurately regulate the gas pressure of each component in the entire working gas path. When the gas pressure of a single component changes, it will affect the gas pressure stability of the entire working gas path, thereby affecting the preparation of powder. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention discloses a control system for the preparation of micron-sized spheroidized powders or nano-powders, employing the following technical solution:

[0005] A method for controlling the preparation of micron-sized spheroidized powder or nanopowder is provided, applied to a control system for the preparation of micron-sized spheroidized powder or nanopowder. The control system includes a gas supply device, a preparation device, a collection device, a cooling device, a vacuum pump, and a controller. Valves and / or switches for adjustment and control are provided between the connecting parts of each device. The method includes the following steps:

[0006] Step 1: In the initial micron-spheroidized powder or nano-powder preparation system, all components and valves are in the closed state. The controller opens the valves and / or switches between the gas supply device and the preparation device, controls the vacuum pump to start and perform vacuuming operation on the gas supply device and the preparation device, and simultaneously controls the cooling device to cool the vacuum pump.

[0007] Step 2: The controller shuts down the vacuum pump and stops the cooling device from cooling the vacuum pump;

[0008] Step 3: The controller controls the gas supply device to fill the preparation device with working gas, and each component in the preparation device reaches the preset gas pressure. The controller adjusts the gas pressure of each component in the gas supply device.

[0009] Step 4: The controller controls the valves and / or switches on the cooling pipes connecting the cooling device and the preparation device to open;

[0010] Step 5: The controller adjusts the air pressure of the air supply device and each component of the preparation device in a PID manner to maintain a stable state;

[0011] Step 6: The controller powers on each component in the preparation device to start up and achieve the working state;

[0012] Step 7: The controller controls the material to flow in the preparation device under the blowing of the working gas. The preparation device performs plasma spheroidization or nano-processing to prepare micron-sized spheroidized powder or nano-powder. The prepared powder is then condensed and sieved.

[0013] Step 8: The controller controls the vacuum pump to start, the vacuum pump evacuates the collecting device, and at the same time controls the cooling device to cool the vacuum pump.

[0014] Step 9: The controller shuts down the vacuum pump, stops the cooling device from cooling the vacuum pump, opens the valve and / or switch between the collecting device and the preparation device, and the collecting device classifies and collects the powder sieved in the preparation device.

[0015] Step 10: The working gas in the preparation device is returned to the gas supply device after filtration.

[0016] Furthermore, the gas supply device includes a gas source, a pressure stabilizing tank, a buffer tank, a dryer, and a gas storage tank; the preparation device includes a silo, a feeder, a radio frequency plasma torch, a main unit compartment, a cyclone separator, a powder collection compartment, a filter, and a booster; and the cooling device includes a water chiller and a fan.

[0017] Furthermore, in step 1, the controller controls the water chiller to start, the valve at the outlet of the water chiller to open, and the valve between the water chiller and the vacuum pump to open. The controller also controls the switches or valves on the working gas path between the hopper, the feeder, the filter, the radio frequency plasma torch, the main unit compartment, the cyclone separator, and the powder collection compartment to open. The controller controls the vacuum pump to open the valves between the hopper, the feeder, the powder collection compartment, the pressure stabilizing tank, and the buffer tank, respectively. The vacuum pump is then activated to perform a vacuuming operation on the working gas path consisting of the hopper, the feeder, the radio frequency plasma torch, the main unit compartment, the cyclone separator, the powder collection compartment, the filter, the booster, and the buffer tank in sequence. The vacuum pump also performs a vacuuming operation on the main gas supply path consisting of the buffer tank, the dryer, and the pressure stabilizing tank in sequence.

[0018] Furthermore, in step 2, the controller controls the valves between the vacuum pump and the silo, the feeder, the powder collection silo, the pressure stabilizing tank, and the buffer tank to close. The controller also controls the vacuum pump to close and the valve between the water chiller and the vacuum pump to close. The gas source is turned on, and the valve between the gas source and the buffer tank is opened. The working gas enters the buffer tank for storage. The working gas in the buffer tank is dried by the dryer and then enters the pressure stabilizing tank. The main gas supply line is connected, and the controller automatically controls the pressure of the buffer tank and the pressure stabilizing pipe.

[0019] Furthermore, in step 2, when the working gas pressure of the buffer tank is greater than the preset pressure value of the buffer tank, the valve between the buffer tank and the gas storage tank is opened, and the working gas enters the gas storage tank for standby. At this time, the controller controls the valve between the gas source and the buffer tank to close.

[0020] Furthermore, in step 3, the controller controls the pressure stabilizing tank to supply gas to the radio frequency plasma torch, and simultaneously controls the valves of each gas supply branch to open. The pressure stabilizing tank fills the silo, the feeder, the radio frequency plasma torch, the main unit silo, the cyclone chamber, the powder collection silo, the filter, and the booster with working gas to reach the preset gas pressure. The controller then closes all output gas valves of the pressure stabilizing tank and enters a static standby state.

[0021] Furthermore, in step 5, the controller controls the pressure stabilizing tank to control the opening of each regulating valve of the radio frequency plasma torch using a PID method. This controls the valves between the radio frequency plasma torch and the main unit compartment, the cyclone separator and the powder collection compartment, the powder collection compartment and the filter, the filter and the booster compressor, and the booster compressor and the buffer tank to all open. The valve between the buffer tank and the pressure stabilizing tank is also opened. The controller controls the booster compressor to start and controls the booster compressor motor speed using a PID method based on the main unit compartment pressure, thereby controlling the booster compressor's air extraction capacity. The controller also controls the opening of the regulating valve between the pressure stabilizing tank and the buffer tank using a PID method based on the preset pressure of the pressure stabilizing tank, and the equipment enters a dynamic standby state.

[0022] Furthermore, in step 6, the controller powers on each component and starts the radio frequency plasma torch. The controller controls the opening of each valve at the radio frequency plasma torch so that the pressure in each part of the equipment reaches the preset value of the working state. The gas flow rate in each pipeline between the radio frequency plasma torch and the pressure stabilizing tank reaches the preset value. When the radio frequency plasma torch is working, the gas expands due to heat. The controller will automatically discharge the excess gas to the gas storage tank for backup according to the preset pressure value of the buffer tank. If the pressure in each part does not reach the working state value, the controller will control the gas source to replenish the buffer tank according to the preset value.

[0023] Furthermore, in step 7, the controller controls the valve between the pressure stabilizing tank and the feeder, and controls the output gas flow rate to the required value according to the process requirements. The material is fed from the hopper through the feeder under the blowing of the working gas, and enters the radio frequency plasma torch for plasma spheroidization or nano-processing. The spheroidized powder is condensed in the main unit chamber. Micron-sized powder remains in the main unit chamber, while other powders enter the cyclone separator for sieving. Nano-sized powders enter the powder collection chamber. When necessary, the valve between the buffer tank and the main unit chamber can be quickly opened and closed to purge the observation window of the main unit chamber.

[0024] Furthermore, in step 9, the controller controls the opening of the switch valve at the outlet of the gas storage tank, connecting the auxiliary gas supply circuit consisting of the buffer tank, the gas storage tank, and the collection device. The gas storage tank fills the collection device with working gas. The controller automatically closes the valve body of the gas storage tank and the collection device according to the preset working pressure value of the collection device. The controller controls the collection device to work, collecting the powder in the corresponding connected main unit compartment, cyclone separator, and powder collection compartment.

[0025] By adopting the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The controller of this invention controls the pressure stabilizing tank to provide working gas to the silo, feeder, radio frequency plasma torch, main unit silo and powder collection silo respectively, and controls the opening of each valve body through PID control method. It can effectively balance and control the internal gas pressure required by each component, and can also adjust the internal pressure and flow rate of each component separately to reduce the impact on the gas pressure of other components.

[0027] (2) The controller of this invention controls the buffer tank to discharge excess gas into the storage tank and controls the storage tank to supply gas to the collection device. This avoids the pressure stabilizing tank from directly regulating the gas pressure of the collection device, reduces the load on the pressure stabilizing tank, and also avoids the gas in the storage tank from being directly discharged into the atmosphere, thus avoiding the waste of working gas. The working gas is recycled, saving costs and reducing environmental pollution.

[0028] (3) The powder prepared by this invention has good sphericity, no hollow spheres, few satellite spheres, good flowability, and can be graded and recycled, enabling the sieving of different grades of powder, which is beneficial to obtaining spherical micron powder and nano powder with good purity. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the principle of a micron-sized spheroidized powder or nano-powder preparation control system according to the present invention;

[0030] Figure 2 This is a schematic diagram of gas flow during vacuuming before powder preparation in the micron-spherical powder or nano-powder preparation control system of the invention embodiment;

[0031] Figure 3 This is a schematic diagram of material flow with airflow during the powder preparation process in the powder preparation control system for micron-sized or nano-sized powders, as described in an embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram of the airflow direction during the vacuuming process in the powder collection process of the metal micron-spheroidized powder or nano powder preparation control system in an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of the airflow direction during powder collection in the micron-spherical powder or nano-powder preparation control system of this invention.

[0034] In the diagram: 1. Hopper; 2. Feeder; 3. Feeding device; 4. RF plasma torch; 5. Main unit hopper; 6. First powder collection device; 7. Cyclone separator; 8. Second powder collection device; 9. Third powder collection device; 10. Powder collection bin; 11. Filter; 12. Booster; 13. Buffer tank; 14. Pressure stabilizing tank; 15. Air storage tank; 16. Air source; 17. Fan; 18. Water chiller; 19. Humidity detection device; 20a. First cooling switch valve; 20b. Second cooling switch valve; 2 0c, Automatic on / off valve; 20d, Third cooling on / off valve; 20e, Fourth cooling on / off valve; 20f, Fifth cooling on / off valve; 20g, Sixth cooling on / off valve; 20h, Seventh cooling on / off valve; 21a, First flow controller; 21b, Second flow controller; 21c, Third flow controller; 21d, Fourth flow controller; 21e, Fifth flow controller; 21f, Sixth flow controller; 22a, First regulating valve; 22b, Second regulating valve; 22c, Third Control valve; 22d, fourth control valve; 22e, fifth control valve; 23a, first switching valve; 23b, second switching valve; 23c, third switching valve; 23e, fourth switching valve; 23f, sixth switching valve; 23g, seventh switching valve; 23h, eighth switching valve; 23i, ninth switching valve; 23j, tenth switching valve; 23k, eleventh switching valve; 23m, twelfth switching valve; 23n, thirteenth switching valve; 23p, fourteenth switching valve; 23q, fifteenth switching valve Valve; 23r, sixteenth switching valve; 23s, seventeenth switching valve; 23t, eighteenth switching valve; 23w, nineteenth switching valve; 23x, twentieth switching valve; 23y, twenty-first switching valve; 23z, twenty-second switching valve; 24, dryer; 25a, first safety valve; 25b, second safety valve; 25c, third safety valve; 25d, twenty-third switching valve; 26, high-temperature gate valve; 27a, first check valve; 27b, second check valve; 28, pressure control valve. Detailed Implementation

[0035] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that in the description of the present invention, terms such as "upper," "lower," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. This is merely for ease of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, it should not be construed as a limitation of the present invention.

[0036] Specific Implementation Example 1, combined with Figures 1 to 5A micron-spherical powder or nanopowder preparation control system is used to prepare irregular metal or non-metal powders into micron-spherical powders or nanopowders that meet the requirements of use. The prepared micron-spherical powders or nanopowders are spherical powders. The system includes a gas supply device, a preparation device, a collection device, a monitoring device, an electrical control system, a cooling device, and a controller.

[0037] The gas supply device is used to provide the working gas required by the system, including a gas source 16, a gas storage tank 15, a buffer tank 13, a pressure stabilizing tank 14, and a dryer 24. The gas source 16, the buffer tank 13, the dryer 24, and the pressure stabilizing tank 14 are connected in sequence. The pressure stabilizing tank 14 is connected to the preparation device to provide working gas with stable pressure. The buffer tank 13 is connected to the preparation device for purging or back-purging. The buffer tank 13 is also connected to the gas storage tank 15 to store excess working gas. The gas source 16 is also connected to the gas storage tank 15 and the preparation device respectively.

[0038] The preparation device prepares irregular powder into spherical micron-sized powder or nano-powder. It includes a hopper 1, a feeder 2, an RF plasma torch 4, a main unit hopper 5, a cyclone separator 7, a powder collection hopper 10, a filter 11, and a booster 12 connected in sequence. The hopper 1, feeder 2, and RF plasma torch 4 are respectively connected to a pressure stabilizing tank 14, and the gas pressure is regulated and maintained by the pressure stabilizing tank 14. The main unit hopper 5, filter 11, and powder collection hopper 10 are respectively connected to a buffer tank 13. The buffer tank 13 can purge the observation window of the main unit hopper 5 for easy observation, and back-purge the filter 11 and powder collection hopper 10 to help the collection device collect powder. The booster 12 is connected to the buffer tank 13 to recover the working gas for recycling and to increase the power of the working gas circulation in the working gas path, and to control the pressure of the main unit hopper to remain stable.

[0039] The collection device is used to collect powder in the preparation device, including a first powder collection device 6, a second powder collection device 8 and a third powder collection device 9. The first powder collection device 6 is connected to the main unit compartment 5 and collects micron powder with a particle size greater than or equal to 3 microns. The second powder collection device 8 is connected to the cyclone separator 7 and collects medium-sized powder with a particle size greater than 800 nanometers and less than or equal to 10 micrometers. The third powder collection device 9 is connected to the powder collection bin 10 and collects nano powder with a particle size less than or equal to 800 nanometers.

[0040] In this embodiment, there is one powder collection bin. In other embodiments, there may be multiple powder collection bins connected in parallel, and multiple third powder collection devices are provided at the same time, with one third powder collection device connected to each powder collection bin.

[0041] The cooling device is used to cool the preparation device, including a water chiller 18 and a fan 17. The water chiller 18 is connected to the feeder 2, the radio frequency plasma torch 4, the main unit chamber 5, the cyclone separator 7, the powder collection chamber 10, and the filter 11 respectively, and cools each component. The fan 17 is connected to the radio frequency plasma torch 4 and cools it with air.

[0042] The monitoring device monitors the working status of the preparation device, including multiple cameras and a display. The multiple cameras are connected to the display and are respectively installed in the material bin 1, feeder 2, radio frequency plasma torch 4, and main unit bin 5.

[0043] The controller provides electrical control over each component through the electrical control system.

[0044] Each connecting component is equipped with a valve body and / or switch for adjustment and control. The controller is connected to each component to control the operation of each component, and is also connected to the valve body and / or switch between each component to control the opening and closing of each valve body and / or switch, and to monitor the pressure, flow rate, temperature, etc. of each pipeline.

[0045] Furthermore, the silo 1, feeder 2, radio frequency plasma torch 4, main unit chamber 5, cyclone separator 7, powder collection chamber 10, filter 11, booster 12, and buffer tank 13 are sequentially connected to form a working air path. A feeding device 3 is installed between the silo 1 and the feeder 2. A first switching valve 23a is installed between the feeder 2 and the radio frequency plasma torch 4. A high-temperature gate valve 26 is installed between the radio frequency plasma torch 4 and the main unit chamber 5. For the specific structure and working principle of the high-temperature gate valve 26, please refer to the bidirectional sealing high-temperature gate valve for nanomaterials disclosed in CN209587180U. A cyclone separator 7 and powder collection chamber 10 are connected to form a working air path. The tenth switch valve 23j; the sixth switch 23f between the powder collection bin 10 and the filter 11; the twelfth switch valve 23m between the filter 11 and the booster 12; the thirteenth switch valve 23n between the booster 12 and the buffer tank 13; and a second anti-backflow check valve 27b between the thirteenth switch valve 23n and the booster 12. The working gas blows the powder into the working gas path, where it flows to the radio frequency plasma torch 4 for high-temperature heating, condenses in the main unit bin 5, and some particles remain in the main unit bin 5. These particles are then blown again by the working gas to the cyclone separator 7 for separation. Finally, the working gas circulates back to the buffer tank 13. The controller's switches can open and close the current pipeline according to the working process, thereby controlling the amount of powder flowing from the main unit bin 5 to the cyclone separator 7 and the powder collection bin 10.

[0046] Furthermore, the gas source 16, buffer tank 13, dryer 24, and pressure stabilizing tank 14 are sequentially connected to form a main gas supply line. The pressure stabilizing tank 14 is connected to the silo 1, feeder 2, and radio frequency plasma torch 4 to form gas supply branches. Regulating valves are installed between adjacent components of the main gas supply line. A 23rd switch valve 25d is installed at the outlet of the gas source 16 to promptly disconnect the gas source 16 from the main gas supply line. A fourth regulating valve 22d is installed between the 23rd switch valve 25d and the buffer tank 13. A first regulating valve 22a is installed between the buffer tank 13 and the dryer 24. A 20th switch valve 23x is installed between the pressure stabilizing tank 14 and the silo 1. A second regulating valve 22b is installed between the pressure stabilizing tank 14 and the feeder 2. The controller controls the powder feeding gas flow rate, the feeding amount, and the initial rate of injection into the radio frequency plasma torch 4. Three gas supply branches are set between the pressure stabilizing tank 14 and the radio frequency plasma torch 4. The three gas supply branches are respectively connected to the center gas, side gas, and cooling gas of the radio frequency plasma torch 4. Each branch is equipped with a third regulating valve 22c, a fifth regulating valve 22e, and a sixth regulating valve 22f. The controller controls the opening of the third regulating valve 22c, the fifth regulating valve 22e, and the sixth regulating valve 22f, thereby regulating the flow rate of the center gas, side gas, and cooling gas of the radio frequency plasma torch 4. This controls the on / off state of each gas supply branch and the stability of the gas pressure, ensuring the stability of the working gas pressure in the hopper 1, feeder 2, radio frequency plasma torch 4, main unit hopper 5, and powder collection hopper 10. The pressure in the main unit hopper 5, the combined flow rate of each gas, and the cooling temperature determine the spheroidization rate of the powder and the particle size of the nanoparticles. The center gas is used to ionize and generate the plasma flame, the side gas is used as an auxiliary gas or protective gas for the center gas, and the cooling gas is used to cool the generating device of the radio frequency plasma torch.

[0047] When the radio frequency plasma torch 4 is working, the power supply is connected. When it starts working, the voltage is increased, the fifth regulating valve 22e connecting to the side gas is closed, the sixth regulating valve 22f connecting to the cooling gas is opened, and the third regulating valve 22c connecting to the center gas is opened to ignite the radio frequency plasma torch 4. After ignition, the fifth regulating valve 22e connecting to the side gas is opened, and the radio frequency plasma torch 4 enters normal operation.

[0048] Another startup scheme for the radio frequency plasma torch 4 is as follows: When starting work, the voltage is increased, the fifth regulating valve 22e connecting to the side gas is closed, the sixth regulating valve 22f connecting to the cooling gas is opened, the third regulating valve 22c connecting to the center gas is closed, and the pressure control valve 28 between the gas source 16 and the radio frequency plasma torch 4 is opened, so that the pure gas from the gas source is directly supplied to the center gas to ignite the radio frequency plasma torch 4. After ignition, the pressure control valve 28 is closed, the fifth regulating valve 22e connecting to the side gas is opened, and the third regulating valve 22c connecting to the center gas is opened, and the radio frequency plasma torch 4 enters normal operation.

[0049] Furthermore, the buffer tank 13, the gas storage tank 15, and the collecting device are sequentially connected to form an auxiliary gas supply line. A nineteenth switch valve 23w is installed on the auxiliary gas supply line between the buffer tank 13 and the gas storage tank 15. When the working gas pressure in the buffer tank 13 exceeds the range, the nineteenth switch valve 23w opens, discharging the excess working gas into the gas storage tank 15. The gas storage tank 15 can also replenish the buffer tank 13 with gas to ensure stable gas pressure in the buffer tank 13. A switch valve is installed on the auxiliary gas supply line between the gas storage tank 15 and the collecting device. A seventeenth switch valve 23s is connected to the gas outlet of the gas storage tank 15. The first powder collecting device 6 is connected to the seventeenth switch valve 23s through a second switch valve 23b installed at the outlet. The second powder collecting device 8 is connected through the outlet... The third switch valve 23c is connected to the seventeenth switch valve 23s. The third powder collection device 9 is connected to the seventeenth switch valve 23s via the fifth switch valve 23e. The seventeenth switch valve 23s can control the opening and closing of the auxiliary gas supply line between the gas storage tank 15 and the collection device. The second switch solenoid valve 23b, the third switch valve 23c, and the fifth switch valve 23e control the gas entering the first powder collection device 6, the second powder collection device 8, and the third powder collection device 9, respectively. The working gas released from the buffer tank 13 due to excessive pressure into the gas storage tank 15 provides a protective atmosphere for the collection device. This avoids the problem of unstable gas pressure caused by directly using the working gas in the pressure stabilizing tank 14 to the preparation device, and makes reasonable use of the released working gas.

[0050] The buffer tank 13 delivers the working gas exceeding the internal pressure to the gas storage tank 15, saving resources. The gas storage tank 15 supplies gas to the collection device separately, without affecting the working gas supplied by the pressure stabilizing tank 14 in the working gas line. This further ensures the stability of the gas flow field of the entire system and facilitates the separate control of the pressure in the preparation device and the collection device.

[0051] The buffer tank 13 is connected to the filter 11 by the eleventh switch valve 23k and to the powder collection bin 10 by the seventh switch valve 23g. When preparing to collect powder, the airflow back-purges the filter 11 and the powder collection bin 10, which helps to collect powder.

[0052] Furthermore, a twenty-third switch valve 25d is installed at the outlet of the gas source 16 and connected to the gas storage tank 15 through the eighteenth switch valve 23t. The eighteenth switch valve 23t controls the connection and disconnection between the gas storage tank 15 and the gas source 16. The eighteenth switch valve 23t is connected to the buffer tank 13 through the fourth regulating valve 22d. A pressure control valve 27 is connected between the gas source 16 and the radio frequency plasma torch 4. It is opened before the pressure stabilizing tank 14 supplies gas to the radio frequency plasma torch 4, so that the gas source 16 is connected to the radio frequency plasma torch 4, which serves as an ignition mechanism.

[0053] Furthermore, the water chiller 18 is connected to the feeder 2, the radio frequency plasma torch 4, the main unit compartment 5, the cyclone separator 7, the powder collection bin 10, and the filter 11 as cooling pipes. An automatic switching valve 20c is installed at the outlet of the water chiller 18 for overall control of the cooling water. Cooling switching valves are installed on the cooling pipes. A first cooling switching valve 20a is installed between the automatic switching valve 20c and the feeder 2; a second cooling switching valve 20b is installed between the automatic switching valve 20c and the radio frequency plasma torch 4; a third cooling switching valve 20d is installed between the automatic switching valve 20c and the main unit compartment 5; a fourth cooling switching valve 20e is installed between the automatic switching valve 20c and the cyclone separator 7; and a sixth cooling switching valve 20g is installed between the automatic switching valve 20c and the powder collection bin 10. A seventh cooling switch valve 20h is installed between 20c and filter 11 to control and regulate the cooling water flow on each cooling pipe, ensuring that the working temperature of each component, including feeder 2, RF plasma torch 4, main unit chamber 5, cyclone separator 7, powder collection chamber 10, and filter 11, is suitable and preventing damage to the components due to excessive temperature. Specifically, each of the feeder 2, RF plasma torch 4, main unit chamber 5, cyclone separator 7, powder collection chamber 10, and filter 11 is also connected to the water chiller 18 via a cooling circuit (not shown in the figure) to recover and reuse cooling water, thus saving water resources. Each cooling switch valve is used to control the liquid flow on each cooling pipe, which can cool and reduce the temperature of the components connected to each cooling pipe, ensuring the normal operating temperature required for each connected component.

[0054] Furthermore, the micron-sized spheroidized powder or nano-powder preparation control system also includes a vacuum pump 21, which is controlled by a controller. The vacuum pump 21 is connected to the first powder collection device 6, the second powder collection device 8, and the third powder collection device 9 through the second switch valve 23b, the third switch valve 23c, and the fifth switch valve 23e, respectively, to perform vacuuming operations on the collection devices. The vacuum pump 21 is also connected to the material hopper 1, the feeder 2, the pressure stabilizing tank 14, the buffer tank 13, and the powder collection hopper 10 through the twenty-first switch valve 23y, the twenty-second switch valve 23z, the fifteenth switch valve 23q, the sixteenth switch valve 23r, and the eighth switch valve 23h, to perform vacuuming operations on the working gas path and the main gas supply path. The inlet of the vacuum pump 21 is connected to the twenty-first switch valve through the fourth switch valve 23d. Vacuum pump 21 is connected to the inlet of vacuum pump 21 via the ninth switch valve 23i, the fifteenth switch valve 23q, the sixteenth switch valve 23r, and the eighth switch valve 23h. This connection plays a central control role when evacuating the collection device. Vacuum pump 21 is emptied via the first one-way valve 27a. Gas storage tank 15, buffer tank 13, and pressure stabilizing tank 14 are emptied via the first safety valve 25a, the second safety valve 25b, and the third safety valve 25c, respectively. This arrangement prevents excess air from existing in the working gas path and the main gas supply path, avoids nitrogen and oxygen in the air from affecting the quality and characteristics of the powder, and ensures the purity of the prepared powder.

[0055] Furthermore, the micron-sized spheroidized powder or nano-powder preparation control system also includes a flow detection device, a humidity detection device 19, and a gas composition detection sensor. Multiple flow detection devices are respectively connected to the hopper 1, the feeder 2, the radio frequency plasma torch 4, and the main unit 5. The humidity detection device 19 is connected to the main unit 5. The humidity detection device 19 and the gas composition detection sensor respectively detect the humidity and gas composition of the cooling gas introduced during operation. The flow detection device, humidity detection device 19, and gas composition detection sensor are connected to the controller to provide feedback on the detection information. Preferably, the flow detection device is a flow controller. A first flow controller 21a is installed between the hopper and the twentieth switch valve 23x, a second flow controller 21b is installed between the feeder 2 and the second regulating valve 22b, a third flow controller 21c, a fourth flow controller 21d and a fifth flow controller 21c are installed on the three gas supply branches connected to the radio frequency plasma torch 4, a fourteenth switch valve 23p is installed between the main unit compartment 5 and the buffer tank 13, and a sixth flow controller 21f is installed between the fourteenth switch valve 23p and the main unit compartment 5, respectively controlling the gas flow of the corresponding gas supply branches, so as to more accurately control the pressure of the working gas in each connected component and maintain pressure stability.

[0056] The control system for preparing micron-sized or nano-sized powders also includes pressure and temperature sensors. Multiple pressure sensors are respectively installed on the hopper 1, feeder 2, radio frequency plasma torch 4, main unit hopper 5, cyclone separator 7, powder collection hopper 10, pressure stabilizing tank 14, buffer tank 13, and gas storage tank 15, and are connected to the controller to detect the working pressure of the above components in real time and provide timely feedback to the controller, so as to facilitate the adjustment of gas flow and component pressure. Multiple temperature sensors are respectively installed on the feeder 2, radio frequency plasma torch 4, main unit hopper 5, cyclone separator 7, powder collection hopper 10, and filter 11, and are connected to the controller to detect the working temperature of the above components in real time and provide timely feedback to the controller, so as to facilitate the adjustment of cooling pipelines and ensure that the working temperature of the above components remains stable.

[0057] The micron-spherical powder or nano-powder preparation control system also includes an air humidity detection device, which is connected to the controller to provide detection information and thereby control the air humidity for cooling. Preferably, the air humidity detection device is connected to the fan 17.

[0058] A method for controlling the preparation of micron-sized spheroidized powder or nanopowder, employing any of the micron-sized spheroidized powder or nanopowder preparation control systems described above, comprises the following steps:

[0059] Step 1: Initially, all components and valves are in the closed state. The controller controls the water chiller 18 to open, the automatic switching valve 20c to open, and the cooling switching valve of the cooling pipeline between the water chiller 18 and the vacuum pump 21 to open. The controller controls the first switching valve 23a, the high-temperature gate valve 26, the tenth switching valve 23j, the twenty-first switching valve 23y, the twenty-second switching valve 23z, the fifteenth switching valve 23q, the sixteenth switching valve 23r, and the eighth switching valve 23h on the working gas line to open, and controls the ninth switching valve 23i at the inlet of the vacuum pump 21. The fourth switch valve 23d and the first one-way valve 27a at the outlet are opened, controlling the vacuum pump 21 to perform vacuuming operation on the working gas path between the material bin 1 and the powder collection bin 10 and the main gas supply path between the pressure stabilizing tank 14 and the buffer tank 13; vacuuming is to prevent too much air from mixing into the entire system, because air contains oxygen, which is easy to oxidize during the preparation of micron-sized spheroidized powder or nano powder, affecting the properties of the prepared powder; the cooling water output from the water chiller 18 is cooled by the vacuum pump 26c through the automatic switch valve 20c and the fifth cooling switch valve 20f;

[0060] Step 2: The controller shuts off the vacuum pump 21, closes the cooling switch valve of the cooling pipe between the water chiller 18 and the vacuum pump 21, turns on the gas source 16, and opens the safety valve 25d and the fourth regulating valve 22d between the gas source 16 and the buffer tank 13. The working gas enters the buffer tank 13 for storage. The working gas in the buffer tank 13 is dried by the dryer 24 and then enters the pressure stabilizing tank 14. The main gas supply line is connected. When the working gas pressure in the buffer tank 13 is greater than the preset pressure value of the buffer tank 13, the nineteenth switch valve 23w is opened, and the working gas enters the storage tank 15 for standby. At this time, the controller closes the valve between the gas source 16 and the buffer tank 13.

[0061] The preset pressure values ​​of buffer tank 13 include static preset pressure values ​​and dynamic preset pressure values. The static preset pressure value is one preset pressure value of buffer tank 13 when the radio frequency plasma torch 4 is not working, and the dynamic preset pressure value is another preset pressure value of buffer tank 13 when the radio frequency plasma torch 4 is working. Generally, the static preset pressure value is lower than the dynamic preset pressure value, mainly because after the radio frequency plasma torch 4 is ignited and working, the gas in the working gas path heats up and expands, and the pressure increases. It is necessary to leave space for gas expansion in buffer tank 13. Therefore, when the radio frequency plasma torch 4 is not working, the working gas pressure in buffer tank 13 is... When the pressure in buffer tank 13 exceeds the static preset pressure value, the nineteenth switch valve 23w opens, and the working gas enters the storage tank 15 for standby. Once the pressure in buffer tank 13 is less than or equal to the static preset pressure value, the nineteenth switch valve 23w closes. When the radio frequency plasma torch 4 is working, if the working gas pressure in buffer tank 13 exceeds the dynamic preset pressure value, the nineteenth switch valve 23w opens, and the working gas enters the storage tank 15 for standby. Once the pressure in buffer tank 13 is less than or equal to the dynamic preset pressure value, the nineteenth switch valve 23w closes. In this step, the radio frequency plasma torch 4 is not working, and the preset pressure value of buffer tank 13 is the static preset pressure value.

[0062] Step 3: The controller pressure tank 14 supplies gas to the radio frequency plasma torch 4, and simultaneously controls the valves of each gas supply branch to open. The twentieth switch valve 23x is opened, and the pressure tank 14 supplies gas to the silo 1 to prevent powder backflow. The second regulating valve 22b, the third regulating valve 22c, the fifth regulating valve 22e, and the sixth regulating valve 22f are opened. The pressure tank 14 fills the feeder 2, the radio frequency plasma torch 4, the main unit silo 5, the cyclone separator 7, the powder collection silo 10, the filter 11, and the booster 12 with working gas to form a protective atmosphere. After the pressure tank 14 stabilizes the gas supply to the radio frequency plasma torch 4 and reaches the preset gas pressure, the flow detection device detects and feeds back to the controller in real time. The controller closes all output gas valves of the pressure tank 14 and enters a static standby state.

[0063] Step 4: The controller controls the operation of the water chiller 18, and the cooling switch valves on each cooling pipe are opened. The first cooling switch valve 20a, the second cooling switch valve 20b, the third cooling switch valve 20d, the fourth cooling switch valve 20e, the sixth cooling switch valve 20g and the seventh cooling switch valve 20h are opened. The feeding device 3 is opened and the high-temperature gate valve 26 is opened. At the same time, the controller controls the operation of each component in the preparation device, and the high-voltage electrical appliances enter the heat preparation state.

[0064] Step 5: The controller controls the pressure stabilizing tank 14 to control the opening of each regulating valve of the radio frequency plasma torch 4 in a PID manner. The high-temperature gate valve 26 between the radio frequency plasma torch 4 and the main unit compartment 5, the tenth switch valve 23j between the cyclone separator 7 and the powder collection compartment 10, the sixth switch valve 23f between the powder collection compartment 10 and the filter 11, the twelfth switch valve 23m between the filter 11 and the booster 12, and the thirteenth switch valve 23n between the booster 12 and the buffer tank 13 are all opened. The regulating valve between the buffer tank 13 and the pressure stabilizing tank 14 is opened. The controller controls the booster 12 to start up and controls the speed of the booster 12 motor in a PID manner according to the pressure of the main unit compartment 5, thereby controlling the pumping capacity of the booster. The gas enters a circulation state in the silo 1, feeder 2, radio frequency plasma torch 4, main unit 5, cyclone separator 7, powder collection silo 10, filter 11, booster 12 and buffer tank 13. The controller controls the opening of the regulating valve between the pressure stabilizing tank 14 and the buffer tank 13 in a PID manner according to the preset pressure of the pressure stabilizing tank 14, and the equipment enters a dynamic standby state.

[0065] Step 6: The controller powers on all components and starts the ignition switch to start the radio frequency plasma torch 4. The controller controls the opening of each regulating valve at the radio frequency plasma torch 4 to make the pressure of each part of the equipment reach the preset value. When the radio frequency plasma torch 4 is working, the gas expands due to heat. The controller will automatically discharge the excess gas to the gas storage tank 15 for later use according to the pressure value set in the buffer tank 13. In this step, the radio frequency plasma torch 4 is working, and the preset pressure value of the buffer tank 13 is a dynamic preset pressure value.

[0066] Step 7: The controller controls the second regulating valve 22b between the pressure stabilizing tank 14 and the feeder 2 to adjust the output gas flow rate according to the process requirements. The material is fed from the hopper 1 through the feeder 2 under the blowing of the working gas and enters the radio frequency plasma torch 4 for plasma spheroidization. The spheroidized powder is condensed in the main unit hopper 5. The micron powder remains in the main unit hopper 5, and the other powders enter the cyclone separator 7 for sieving. The nano powder enters the powder collection hopper 10. When needed, the fourteenth switch valve 23p between the buffer tank 13 and the main unit hopper 5 is quickly opened to purge the observation window of the main unit hopper 5.

[0067] Step 8: The controller controls the vacuum pump 21 to turn on, and the fifth cooling switch valve 20f of the cooling pipeline between the water chiller 18 and the vacuum pump 21 is opened. At the same time, the controller controls the fourth switch valve 23d, the second switch valve 23b, the third switch valve 23c, and the fifth switch valve 23e to open. The vacuum pump 21 evacuates the first powder collection device 6, the second powder collection device 8, and the third powder collection device 9 to prepare for powder collection.

[0068] Step 9: The controller controls the vacuum pump 21 to shut down, the fifth cooling switch valve 20f of the cooling pipeline between the water chiller 18 and the vacuum pump 21 to shut down, controls the eleventh switch valve 23k between the buffer tank 13 and the filter 11 to open, and controls the seventh switch valve 23g between the powder collection bin 10 to open for backflushing, so that the powder can enter the powder collection device. The controller controls the seventeenth switch valve 23s at the outlet of the gas storage tank 15 to open, so that the auxiliary gas supply line is connected. The gas storage tank fills each of the powder collection devices with working gas. The controller controls each of the powder collection devices to work, and collects the powder in the corresponding connected main unit compartment 5, cyclone separator 7 and powder collection bin 10 respectively. Micron powder is collected in the first powder collection device 6, and nano powder is collected in the third powder collection device 9.

[0069] Furthermore, the method for controlling the preparation of micron-sized spherical powders or nanopowders also includes:

[0070] Step 10: The controller controls the filter 11 and the booster 12 to open, and simultaneously controls the opening of the switching valves in the working gas path section between the powder collection bin 10, the filter 11, the booster 12 and the buffer tank 13. The sixth switching valve 23f, the seventh switching valve 23k, the twelfth switching valve 23m and the thirteenth switching valve 23n are opened, and the second one-way valve 27b is opened, so that the working gas in the preparation device is recovered into the buffer tank 13. The controller performs PID control on the speed of the booster 12 to ensure that the pressure in the main chamber 5 is constant. The pressure in the main chamber 5 can be adjusted within the range of 0-130KPa, and can be adjusted according to different powder preparation requirements.

[0071] It should be noted that the booster 12, as the gas circulation power source, must start the circulation before the radio frequency plasma torch 4 is ignited. Under the action of the controller, the gas pressure in the space of each component is at the required intensity. After ignition, it can be automatically or manually adjusted to the required pressure in the working state and the gas pressure of each part can be adjusted according to the process requirements.

[0072] In each operating step, the opening and closing of each component, valve and / or switch only describes the current state. The order of opening and closing of each component and valve and / or switch depends on the actual operation. Generally, the relevant valve and / or switch is opened first, and then the related component is opened. When closing, the relevant component is closed first, and then the relevant valve and / or switch is closed to ensure that each component operates normally and will not be damaged by excessive gas pressure.

[0073] The motor speed of the booster compressor 12 determines the pumping capacity of the booster compressor 12, which in turn determines the pressure of the main chamber 5. The controller uses the PID control method to adjust the motor speed of the booster compressor 12 to ensure that the pressure of the main chamber 5 is at the value required by the process. The preset pressure of the booster compressor 12 is 500 kPa, and the preset pressures of the air source 16, the buffer tank 13, and the pressure stabilizing tank 14 are also 500 kPa. The controller can also adjust the booster compressor 12 using a self-regulating valve.

[0074] The aforementioned micron-spheroidized powder or nano-powder preparation control system also includes an alarm. When gas leakage in the system causes a sudden change in gas pressure or the gas pressure of each component exceeds the preset pressure value, or when cooling water leaks in the cooling pipes, the alarm will sound, prompting personnel to handle and repair the system within a preset time. If the problem is not addressed within the preset time, the system will shut down immediately. When the temperature of each component is too high and exceeds the preset temperature value, the alarm will sound simultaneously, and the system will shut down immediately.

[0075] When the micron-sized or nano-sized powder is prepared and the system needs to be shut down, the system will automatically shut down according to the set program. The automatic shutdown operation steps are as follows: the radio frequency plasma torch 4 is extinguished, the high voltage connected to the radio frequency plasma torch 4 is turned off, after the temperature of each component drops to the shutdown requirement, the gas supply device stops supplying gas, the fan is turned off, the water chiller is turned off, the entire system is shut down, the gas pressure in each component is adjusted to the set pressure value under static conditions, and all valves and / or switches in the system are closed.

[0076] In Example 2, a cooling device is connected to the booster compressor 12, which can be either air-cooled or water-cooled. Preferably, the booster compressor 12 is connected to a water chiller 18 through a cooling switch valve to cool it down and ensure that the booster compressor 12 works normally. An automatic humidifier is also connected to the fan 17, which can automatically turn on or off according to the air humidity detected by the humidity detection device 19 to humidify the air at the fan 17. The fan 17 blows in the humidified air to ensure that the humidity in the system is suitable. Other settings are the same as in Example 1.

[0077] In Example 3, the main unit compartment 5 and the gas storage tank 15 in the micron-spheroidized powder or nano-powder preparation system are connected by a switch valve. The gas storage tank 15 can replenish the main unit compartment 5 with gas to ensure the normal operation of the main unit compartment 5, while not affecting the gas pressure stability of the entire working gas path. Other settings are the same as in Example 1.

[0078] In Example 4, during cold winters, the entire system needs to maintain a constant temperature when the equipment is shut down to prevent malfunctions. The water chiller 18 requires cooling of relevant equipment during operation (feeder 2, RF plasma torch 4, main unit compartment 5, cyclone separator 7, powder collection compartment 10, and filter 11 operate at temperatures below 50°C). When the equipment is shut down, the connected equipment needs to maintain a constant temperature (1°C to 10°C). Therefore, the water tank of the water chiller 18 is connected to an electric heater to maintain a constant temperature within the water tank. In winter, when the temperature drops below zero, to prevent the cooling system from freezing and causing equipment damage, the system automatically... The temperature of each component of the measuring equipment is measured, and the equipment enters the anti-freeze mode. The first cooling switch valve 20a, the second cooling switch valve 20b, the third cooling switch valve 20d, the fourth cooling switch valve 20e, the sixth cooling switch valve 20g, and the seventh cooling switch valve 20h are opened. The electric heater and the water in the water tank of the water chiller 18 circulate in the cooling pipes and cooling circuit to ensure that the components connected to the water chiller 18 maintain a constant temperature. Since the water temperature provided by the water chiller 18 cannot meet the constant temperature requirement of the feeder 2, a heater is connected to the feeder 2. Electric heating or water bath heating can be used to ensure that the feeder 2 operates at a constant temperature. Other settings are the same as in Embodiment 1.

[0079] In this invention, each switching valve, regulating valve, and cooling switching valve can be an electric valve or a solenoid valve, and can be automatically or manually controlled, as long as it enables the smooth flow or cut-off of the fluid medium.

[0080] The parts of this invention not described in detail are prior art. 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 variations 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 claims and their equivalents.

Claims

1. A microspheroidized powder or nanometer powder preparation control method applied to a microspheroidized powder or nanometer powder preparation control system, the microspheroidized powder or nanometer powder preparation control system comprising a gas supply device, a preparation device, a collection device, a cooling device, a vacuum pump and a controller, wherein a valve and / or a switch for adjusting control are arranged between the connecting parts of each device, and characterized in that: The method comprises the following steps: the microspheroidized powder or nanometer powder preparation control system further comprises a gas supply device, a preparation device, a collection device, a cooling device, a vacuum pump and a controller, wherein a valve and / or a switch for adjusting control are arranged between the connecting parts of each device, and characterized in that: Step 1: All parts and all valves in the initial microspherization powder or nanometer powder preparation system are in a closed state, the controller opens the valves and / or switches between the gas supply device and the preparation device, controls the vacuum pump to be opened to perform vacuumizing operation on the gas supply device and the preparation device, and controls the cooling device to cool the vacuum pump; the gas supply device comprises a gas source, a pressure stabilizing tank, a buffer tank, a dryer and a gas storage tank; the preparation device comprises a material bin, a feeder, a radio frequency plasma torch, a main machine bin, a cyclone separator, a powder collecting bin, a filter and a booster; and the cooling device comprises a water cooling machine and a fan; ​​ Step 2: The controller controls the vacuum pump to be closed and controls the cooling device to stop cooling the vacuum pump; Step 3: The controller controls the gas supply device to fill the preparation device with working gas, and each part in the preparation device reaches a preset gas pressure; the controller adjusts the gas pressure of each part in the gas supply device; the controller controls the pressure stabilizing tank to supply gas to the radio frequency plasma torch, and controls the valves of each gas supply branch to be opened, so that the pressure stabilizing tank fills the material bin, the feeder, the radio frequency plasma torch, the main machine bin, the cyclone separator, the powder collecting bin, the filter and the booster with working gas to reach a preset gas pressure, and the controller closes each output gas valve of the pressure stabilizing tank to enter a static standby state; Step 4: The controller controls the valves and / or switches on the cooling pipeline connected between the cooling device and the preparation device to be opened; Step 5: The controller adjusts the gas pressure of each part of the gas supply device and the preparation device in a PID mode to keep a stable state; Step 6: The controller controls each part in the preparation device to be powered on to reach a working state; Step 7: The controller controls the material to flow in the preparation device under the blowing of the working gas, so that the preparation device performs plasma spherization or nanometerization processing to prepare microspherization powder or nanometer powder, and the prepared powder is condensed and screened; the controller controls the valve between the pressure stabilizing tank and the feeder to control the output gas flow to reach a required value according to process requirements, the material is fed from the material bin to the feeder under the blowing of the working gas, enters the radio frequency plasma torch to perform plasma spherization or nanometerization processing, the spherized powder is condensed in the main machine bin, the micro powder remains in the main machine bin, other powder enters the cyclone separator to be screened, the nanometer powder enters the powder collecting bin, and the valve between the buffer tank and the main machine bin is quickly opened and closed as needed to blow the observation window of the main machine bin; Step 8: The controller controls the vacuum pump to be opened, and the vacuum pump performs vacuumizing operation on the collecting device, while the cooling device cools the vacuum pump; Step 9: The controller controls the vacuum pump to be closed, controls the cooling device to stop cooling the vacuum pump, opens the valves and / or switches between the collecting device and the preparation device, and the collecting device classifies and collects the screened powder in the preparation device. The controller controls the opening of the switch valve at the outlet of the gas tank, and the buffer tank, the gas tank and the collection device form a gas supply auxiliary road, the gas tank fills the working gas of the collection device, and the controller automatically closes the valve body between the gas tank and the collection device according to the preset working pressure value of the collection device. The controller controls the operation of the collection device to collect the powder in the corresponding connected host warehouse, cyclone separator and powder collection warehouse respectively. Step 10: The working gas in the preparation device returns to the gas supply device after filtration.

2. The method according to claim 1, wherein the method is characterized by: In step 1, the controller controls the water cooler to open, the valve body at the outlet of the water cooler to open, and the valve body between the water cooler and the vacuum pump to open. The controller controls the opening of the switch or valve body on the working gas path between the material warehouse, the feeder, the filter, the radio frequency plasma torch, the host warehouse, the cyclone separator, the powder collection warehouse, controls the opening of the valve body between the vacuum pump and the material warehouse, the feeder, the powder collection warehouse, the pressure stabilizing tank, the buffer tank, and controls the vacuum pump to open to perform vacuum operation on the working gas path composed of the material warehouse, the feeder, the radio frequency plasma torch, the host warehouse, the cyclone separator, the powder collection warehouse, the filter, the booster and the buffer tank in turn. The vacuum pump also performs vacuum operation on the gas supply main road composed of the buffer tank, the dryer and the pressure stabilizing tank in turn.

3. The method according to claim 2, wherein the method is characterized by: In step 2, the controller controls the closing of the valve body between the vacuum pump and the material warehouse, the feeder, the powder collection warehouse, the pressure stabilizing tank and the buffer tank. The controller controls the closing of the valve body between the water cooler and the vacuum pump, the opening of the valve body between the gas source and the buffer tank, and the opening of the gas source. The working gas enters the buffer tank for storage, and the working gas in the buffer tank enters the pressure stabilizing tank after being dried by the dryer. The gas supply main road is communicated, and the controller automatically controls the pressure of the buffer tank and the pressure stabilizing tube.

4. The method according to claim 3, wherein the method is characterized by: In step 2, when the working gas pressure of the buffer tank is greater than the preset pressure value of the buffer tank, the valve body between the buffer tank and the gas tank is opened, and the working gas enters the gas tank for standby. At this time, the controller controls the closing of the valve body between the gas source and the buffer tank.

5. The method for controlling the preparation of micron-sized spherical powders or nanopowders as described in claim 4, characterized in that: In step 5, the controller controls the PID control of the opening degree of each adjusting valve of the radio frequency plasma torch by the pressure stabilizing tank, controls the opening of the valve body between the radio frequency plasma torch and the host warehouse, the valve body between the cyclone separator and the powder collection warehouse, the valve body between the powder collection warehouse and the filter, the valve body between the filter and the booster, the valve body between the booster and the buffer tank, and the valve body between the buffer tank and the pressure stabilizing tank. The controller controls the booster to start, and controls the motor speed of the booster to control the gas pumping capacity of the booster in a PID manner according to the pressure of the host warehouse. The controller controls the opening degree of the adjusting valve between the pressure stabilizing tank and the buffer tank in a PID manner according to the preset pressure of the pressure stabilizing tank, and the equipment enters a dynamic standby state.

6. The method according to claim 5, wherein the method is characterized by: In step 6, the controller controls the power of each component, and starts the radio frequency plasma torch, the controller controls the opening of each valve body at the radio frequency plasma torch to make the pressure of each part of the device reach the preset value of the working state, and the gas flow of each pipeline between the radio frequency plasma torch and the pressure stabilizing tank reaches the preset value. When the radio frequency plasma torch works, the gas expands due to heating, and the controller will automatically discharge the excess gas to the gas storage tank for standby according to the preset pressure value of the buffer tank. If the pressure of each part does not reach the working state value, the controller will control the gas source to supplement the buffer tank according to the preset value.

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