An apparatus for preparing nano-powders by a plasma irradiation method

Abstract

The present invention provides an apparatus for preparing nanopowders by plasma irradiation, comprising a furnace body, a powder collecting device, a vaporizing device, and a wire feeding device. The vaporizing device is disposed on the furnace body and above the crucible. The powder collecting device is disposed at the rear of the furnace body via a pipeline. The wire feeding device is disposed outside the furnace body and feeds a base material welding wire into the furnace body. The vaporizing device comprises at least two plasma guns, each connected to a negative electrode and a positive electrode, generating a high-temperature arc between the plasma guns and the crucible. The plasma guns are each provided with a handwheel for adjusting the upward and downward movement of the plasma guns. The base material welding wire is vaporized by the high-temperature arc. The vaporized base material is then blown through the vaporizing device and a horizontal air blowing assembly above the crucible opening to the powder collecting device for collection. The apparatus of the present invention has an ingenious structural design, with each device or component interconnected to ensure the vacuum degree of the equipment during production and processing, reduce the contact between the raw materials and air or oxygen, ensure the production quality of the nanopowder, and facilitate continuous and uninterrupted production.

Description

Technical Field

[0001] The invention relates to equipment for preparing nano powder by irradiation method, in particular to equipment for preparing nano powder by plasma irradiation method. Background Art

[0002] Nano powder is ultrafine powder. Ultrafine powder technology is an emerging process technology. After the material is ultrafinely pulverized, the resulting powder has good surface properties, such as dispersibility and solubility. Since the newly generated particles have significant characteristics such as good surface effect, quantum size effect, small size effect and quantum tunneling effect, ultrafine powder has been widely used in electrical engineering, medicine, chemical industry and other fields. Conventional pulverization technology can be divided into gas phase method, liquid phase method and solid phase method according to the preparation state. It can be divided into amorphous crystallization method, mechanical crushing method, plasma method, atomization method and so on according to whether a chemical reaction occurs. In the existing technology, a plasma gun is used to produce and process the base material. The base material is vaporized under a protective atmosphere and then cooled to prepare nano powder. However, there are the following defects:

[0003] 1. The impurities in the crucible are not cleaned thoroughly before processing, and the crucible is heated unevenly and easily cracked;

[0004] 2. The use of a single plasma gun is prone to damage to internal components, and the long maintenance time causes production interruptions;

[0005] 3. The vaporized base material is easily adsorbed on the inner wall of the furnace, resulting in material waste and cross contamination when replacing other materials;

[0006] 4. Raw materials are easily exposed to air, which affects the purity of nanopowders;

[0007] 5. During production, the machine needs to be stopped to add materials, which is prone to interruption and cannot achieve continuous processing. After the interruption, the machine needs to be vacuumed again, which is inefficient. The material is easily exposed to air, resulting in poor product quality. Summary of the Invention

[0008] The object of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a device for preparing nanopowder by plasma irradiation, which can preheat and automatically clean the crucible, reduce overhaul and maintenance costs, avoid material waste and cross contamination, achieve uninterrupted continuous production, ensure product quality and efficiency, and produce nanopowder materials with high purity.

[0009] The technical solution of the present invention is: an apparatus for preparing nanopowder by plasma irradiation, comprising a furnace body, a powder collecting device, a vaporizing device and a wire feeding device, wherein a crucible is provided in the furnace body, the vaporizing device is arranged on the furnace body and located above the crucible, the powder collecting device is arranged at the rear of the furnace body through a pipeline, the wire feeding device is arranged outside the furnace body and feeds base material welding wire into the furnace body, the vaporizing device comprises at least two plasma guns, the plasma guns are connected to a negative electrode, and the crucible is connected to a positive electrode, so that a high-temperature arc is generated between the two, and each plasma gun is provided with a handwheel for adjusting the upward and downward movement of the plasma gun. The base material welding wire is vaporized by the high-temperature arc, and the vaporized base material is blown into the powder collecting device through the vaporizing device and a horizontal blowing assembly above the crucible opening for collection.

[0010] Preferably, 2-5 plasma guns are provided, more preferably, 2 or 3 plasma guns are provided; the first plasma gun is energized by contacting the bottom of the crucible through the adjustment of the hand wheel, and then the first plasma gun and the crucible are adjusted to a certain distance through the hand wheel. During the adjustment process, a drawn arc, i.e., a high-temperature arc, is formed between the first plasma gun and the crucible, and the distance is 0.1-12 cm, more preferably, the distance is 7-10 cm; the hand wheel is used to adjust the distance between the plasma gun and the crucible, the thickness of the arc, and the temperature of the arc; the first plasma gun preheats the crucible, cleans the residual materials and impurities in the crucible, and blows out protective gas to form a high vacuum in the crucible The state is ensured to be oxygen-free; then the second plasma gun is turned on in the same way, and the high-temperature arcs of the first plasma gun and the second plasma gun are superimposed to ensure that the temperature in the crucible can reach the set temperature. The other plasma guns can be used as backup or continue to be turned on, and the arcs of subsequent plasma guns are also superimposed to ensure that the temperature in the crucible reaches the set temperature and the protective gas is blown out; if a single plasma gun is used to vaporize the base material, the power of a single plasma gun is too large and it is easy to be damaged; if the number of plasma guns exceeds the set number, the installation space is limited and the installation cost will increase; therefore, using multiple plasma guns is convenient to ensure the continuous production of nanopowder.

[0011] Furthermore, a plurality of gas filling points are provided in the furnace body. The gas flow formed by the gas filling in the furnace body prevents the vaporized parent material from being adsorbed on the inner wall of the furnace body and blows the vaporized parent material toward the rear of the furnace body, thereby preventing the vaporized parent material from being adsorbed on the furnace body and causing material waste.

[0012] Furthermore, the furnace body is provided with a furnace door, and the furnace door and the inner wall of the furnace body are paved with a ventilation isolation layer, and the airflow at the inflation point passes through the stainless steel mesh and blows into the furnace body cavity; the ventilation isolation layer is a stainless steel mesh layer or a bubble film, and the surface of the stainless steel mesh layer or the bubble film is a smooth surface, which is convenient for reducing the adsorption effect.

[0013] The ventilation isolation layer is detachably mounted on the inner wall of the furnace body, making it easier to clean the furnace body. It can disperse and insulate the protective gas blown out of the furnace body, further preventing the vaporized base material from being adsorbed on the inner wall of the furnace body, thereby isolating and protecting the inner wall of the furnace body. The ventilation isolation layer can be replaced after multiple uses.

[0014] Furthermore, the blowing assembly includes an air inlet pipe and a blowing nozzle. The air inlet pipe is passed through the furnace door. A blowing nozzle is provided at the inner end of the air pipe, and the blowing nozzle is arranged above the crucible opening. The outer end of the air inlet pipe is connected to a high-pressure gas source, and an electromagnetic valve is provided on the air inlet pipe.

[0015] Furthermore, the blowing components are provided in at least two groups, one of which is provided below the crucible opening, and the remaining groups are provided above the crucible opening in an upper and lower distribution.

[0016] Preferably, at least 2-5 groups of air blowing assemblies are provided; more preferably, at least 3 groups of air blowing assemblies are provided, with one group positioned below the crucible opening and the remaining two groups positioned above the crucible opening and distributed vertically. Positioning the air blowing assemblies below the crucible opening prevents vaporized parent material from adsorbing on the periphery of the crucible and its surroundings. Positioning the two groups above the crucible opening prevents vaporized parent material from passing through the protective gas layer blown by the air blowing assemblies and dispersing upward, thereby preventing excessive dispersion from adsorbing on the inner wall of the furnace.

[0017] Furthermore, it also includes a vacuum glove box, a vacuum exhaust component and an operating platform. The vacuum glove box is arranged below the powder collection device. The vacuum exhaust component is connected to the pipeline through a vacuum tube. The furnace body, wire feeding component and control cabinet are arranged on the operating platform. The control cabinet is used to control the operation of the entire equipment and the setting of operating parameters, operation monitoring, etc.

[0018] Furthermore, the powder collecting device includes a powder collecting tank, a filter element and a driving device. The powder collecting tank is provided with a powder inlet at the upper end and a discharge port at the lower end. The filter element is vertically fixed in the powder collecting tank. At least one brush is provided on the periphery of the filter element. The brush is driven by the driving device on the top of the powder collecting tank and rotates with the filter element as the axis. The brush is used to clean the powder on the inner wall of the powder collecting tank and the outer surface of the filter element. The lower end of the filter element is connected to the exhaust pipe, and the exhaust pipe is connected to the vacuum glove box.

[0019] Preferably, two sets of powder collecting devices are provided to ensure uninterrupted and continuous production. When one of the powder collecting devices is full, it can be switched to the other powder collecting device for collection through a valve. In order to ensure the vacuum degree of the powder collecting device, a vacuum tube is provided in the powder collecting tank, and the vacuum tube is connected to the vacuum exhaust component, and a valve is provided on the vacuum tube.

[0020] Furthermore, the wire feeding device includes a shell, a wire feeder, a bracket and a roller. The shell is provided with a bracket, the roller is arranged in the shell through a fixed axis, the wire feeder is arranged in the shell, and the wire feeding device is connected to the furnace body through a vacuum tube. The wire feeder in a vacuum environment continuously feeds the base material welding wire from the vacuum tube to the chamber crucible. A valve is provided on the vacuum tube, and a vacuum tube is provided on the shell. The vacuum tube is connected to the vacuum exhaust component, and a valve is provided on the vacuum tube.

[0021] Furthermore, the furnace body is also provided with a secondary feeding assembly, including a feeding chamber, a drive motor, a solenoid valve and a guide pipe. A number of feeding chambers are provided in the feeding chamber, and the feeding chambers are driven to rotate by the drive motor above the feeding chamber. The solenoid valve is arranged at the outlet of the feeding chamber, and the lower end of the solenoid valve is connected to the guide pipe. The guide pipe guides the raw materials into the crucible. The feeding chamber is connected to the vacuum exhaust assembly through a vacuum exhaust pipe, and a valve is provided on the vacuum exhaust pipe.

[0022] Furthermore, a dust filter is vertically provided on the pipeline, and the dust filter is connected to the vacuum exhaust component through a vacuum exhaust pipe;

[0023] Or a pneumatic ball valve is provided on one end of the pipeline close to the powder collecting tank; preferably, a pneumatic ball valve is provided on the powder inlet pipe of the powder collecting tank, and the powder inlet pipe is connected to the pipeline, and the pipeline can be connected to multiple powder inlet pipes to ensure continuous production;

[0024] Or the pipeline is further provided with a branch pipe, on which a resistance vacuum gauge, a sensor and a pressure gauge are provided; used to detect the vacuum degree, pressure and oxygen amount in the furnace body; to ensure that the production environment is within the set range;

[0025] Or the powder collecting tank and the furnace body are both provided with explosion-proof openings to prevent explosion due to excessive temperature or entry of air;

[0026] Alternatively, the furnace door, furnace body, pipeline and powder collecting tank are all provided with cooling interlayers, and cooling water flows through the interlayers to ensure the cooling effect on the vaporized parent material and the formation of nano powders.

[0027] Before processing, close the furnace door and the valves connecting the furnace body to the outside world, so that the furnace body, powder collecting tank and vacuum exhaust pipe together form a closed chamber; then the vacuum exhaust component starts to evacuate the entire chamber. When the interior of the chamber reaches the set vacuum environment, argon gas is filled into the furnace door, the inside of the furnace body, the plasma gun and the blowing component to prevent air from entering and ensure the vaporization environment inside the furnace body.

[0028] The present invention has the following beneficial effects:

[0029] 1. Multiple plasma guns are started in sequence. The first plasma gun is used to preheat and clean the crucible to avoid cracking due to uneven heating of the crucible, thus ensuring the service life of the crucible. The arcs between the subsequently started plasma guns and the crucible cross or overlap to ensure the processing temperature of the material. The distance between the plasma gun and the crucible is adjusted by the hand wheel to adjust the arc thickness and the temperature in the crucible.

[0030] 2. Several inflation points are set on the inner wall of the furnace body to blow the vaporized parent material into the furnace body cavity to avoid the vaporized parent material being adsorbed on the inner wall of the furnace body and causing material waste; and a ventilation isolation layer is laid on the inner wall of the furnace body to disperse and even the protective gas blown out from the inflation points, and further reduce the adsorption of the vaporized parent material on the inner wall of the furnace body. The surface of the ventilation isolation layer is smooth, and the adsorption effect of the vaporized parent material is poor, which plays an isolating and protective role and heat insulation role on the inner wall of the furnace body, making it easy to clean the furnace body; the ventilation isolation layer is detachable and arranged in the furnace body to facilitate the cleaning of the nano powder in the furnace body to avoid cross contamination.

[0031] 3. The wire feeding device and secondary feeding components all use vacuum to isolate the raw materials from the air before entering the furnace body, ensuring the quality of nano powder production and enabling continuous production of alloy powder, avoiding interruption of production due to adding raw materials in the middle, and avoiding tedious processes such as mixing and briquetting of raw materials before processing.

[0032] 4. Multiple groups of blowing components are set to blow air above and below the crucible opening respectively, blowing the vaporized parent material to the tail of the furnace body, preventing the vaporized parent material from passing through the horizontal air flow layer above the crucible and being scattered in the furnace body, further preventing the vaporized parent material from being adsorbed on the inner wall of the furnace body and preventing the vaporized parent material from being adsorbed on the outer surface of the crucible and its surroundings.

[0033] 5. The equipment structure of the present invention is cleverly designed, and the various devices or components are combined with each other to ensure the vacuum degree of the equipment production and processing, reduce the contact between raw materials and air or oxygen, ensure the production quality of nanopowder, and facilitate continuous and uninterrupted production.

[0034] The detailed structure of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 - is a schematic diagram of the structure of the present invention;

[0036] Figure 2 - is another structural schematic diagram of the present invention;

[0037] Figure 3 - is a schematic diagram of the furnace structure of the present invention;

[0038] 1-wire feeding device, 2-operating platform, 3-air blowing assembly, 4-crucible, 5-plasma gun, 6-handwheel, 7-infrared temperature measuring mechanism, 8-explosion-proof port, 9-dust filter, 10-pipeline, 11-pneumatic ball valve, 12-drive motor, 13-brush, 14-cooling interlayer, 15-vacuum glove box, 16-vacuum exhaust assembly, 17-observation window, 18-secondary feeding assembly, 19-first plasma gun, 20-second plasma gun, 21-wire inlet pipe, 22-vacuum exhaust pipe, 23-branch pipe, 24-powder collecting tank, 25-pneumatic powder butterfly valve, 26-control cabinet, 27-resistance vacuum gauge, 28-sensor, 29-pressure gauge, 30-material guide pipe, 31-furnace door, 32-arc, 33-ventilation isolation layer, 34-inflating point. DETAILED DESCRIPTION

[0039] As shown in the accompanying drawings: A device for preparing nanopowder by plasma irradiation, including a furnace body under a vacuum protective atmosphere, a powder collecting device, a vaporization device and a wire feeding device 1, a crucible 4 is provided in the furnace body, the vaporization device is arranged on the furnace body and is located above the crucible 4, the powder collecting device is arranged at the tail of the furnace body through a pipe 10, the wire feeding device 1 is arranged outside the furnace body and transports the base material welding wire into the furnace body, the vaporization device includes at least two plasma guns 5, the plasma gun 5 is connected to the negative electrode, and the crucible 4 is connected to the positive electrode to generate a high-temperature arc 32 between the two, and the plasma gun 5 is provided with a handwheel 6 for adjusting the up and down movement of the plasma gun 5. The base material welding wire is vaporized by the high-temperature arc 32, and the vaporized base material is blown into the powder collecting device through the vaporization device and the horizontal blowing component 33 above the opening of the crucible 4.

[0040] Preferably, 2-5 plasma guns 5 are provided, more preferably, 2 or 3 plasma guns 5 are provided; the first plasma gun 19 is energized by contacting the bottom of the crucible 4 through the adjustment of the hand wheel 6, and then the first plasma gun 19 and the crucible 4 are adjusted to a certain distance through the hand wheel 6. During the adjustment process, a drawn arc, i.e., a high-temperature arc 32, is formed between the first plasma gun 5 and the crucible 4, with a distance of 0.1-12 cm, more preferably, a distance of 7-10 cm; the hand wheel 6 is used to adjust the distance between the plasma gun and the crucible 4, the thickness of the arc 32 and the temperature of the arc 32; the first plasma gun 19 preheats the crucible 4, cleans the residual materials and impurities in the crucible 4, and blows out the protective gas to form a high degree of the crucible 4 The vacuum state is ensured to be oxygen-free; then the second plasma gun 20 is turned on in the same way, and the high-temperature arcs 32 of the first plasma gun 19 and the second plasma gun 20 are superimposed to ensure that the temperature in the crucible 4 can reach the set temperature. The other plasma guns 5 can be used as backup or continue to be turned on, and the arcs 32 of the subsequent plasma guns 5 are also superimposed to ensure that the temperature in the crucible 4 reaches the set temperature and blow out the protective gas; if a single plasma gun 5 is used to vaporize the base material, the power of the single plasma gun 5 is too large and it is easy to be damaged; if the number of plasma guns 5 exceeds the set number, the installation space is limited and the installation cost will increase; therefore, using multiple plasma guns 5 is convenient to ensure the continuous production of nanopowder.

[0041] The present invention also includes a vacuum glove box 15, a vacuum exhaust assembly 16 and an operating platform 2. The vacuum glove box 15 is arranged below the powder collection device. The vacuum exhaust assembly 16 is connected to the pipeline 10 through a vacuum pipe 22. The operating platform 2 is arranged on the frame. The furnace body, wire feeding assembly and control cabinet 26 are arranged on the operating platform 2. The control cabinet 26 is used to control the operation of the entire equipment, the setting of operating parameters, operation monitoring, etc.

[0042] In an embodiment, the powder collecting device includes a powder collecting tank 24, a filter element and a driving device. The powder collecting tank 24 is provided with a powder inlet at the upper end and a discharge port at the lower end. The filter element is vertically fixed in the powder collecting tank 24. At least one brush 13 is provided on the periphery of the filter element. The brush 13 is driven by the driving device on the top of the powder collecting tank 24 and rotates with the filter element as the axis. The brush 13 is used to clean the powder on the inner wall of the powder collecting tank 24 and the outer surface of the filter element to prevent nano-powder materials from being adsorbed on the inner wall of the powder collecting tank 24 and the outer surface of the filter element. The lower end of the filter element is connected to an exhaust pipe, and a pneumatic powder butterfly valve 25 is provided on the exhaust pipe. The exhaust pipe is connected to a vacuum glove box 15.

[0043] In an embodiment, the vacuum exhaust assembly 16 includes a vacuum pump and an integrated vacuum tube 22. The integrated vacuum tube 22 is connected to the vacuum pump. The setting of the integrated vacuum tube 22 facilitates vacuuming of multiple components at the same time or vacuuming of a certain component individually, thereby ensuring a vacuum environment for the operation of the equipment.

[0044] In the embodiment, a dust filter 9 is vertically provided on the pipe 10 at the tail end of the furnace body. The dust filter 9 is connected to the vacuum extraction component 16 through a vacuum pipe 22. When the vacuum extraction component 16 extracts the vacuum degree in the equipment cavity to the required degree, the valve in front of the filter of the vacuum extraction component 16 is closed. At this time, when powder is made in the chamber, the powder may enter the vacuum pipe 10. The function of the dust filter 9 in the middle section of the pipe 10 is to block the powder from continuing to penetrate into the pipe 10. The advantage of installing the filter vertically is that the powder is not easy to accumulate inside the dust filter 9, thereby avoiding clogging of the dust filter 9.

[0045] Preferably, the pipe 10 is further provided with a branch pipe 23 equipped with a resistance vacuum gauge 27, a sensor 28, and a pressure gauge 29 for detecting the vacuum, pressure, and oxygen level within the furnace, thereby ensuring that the production environment is within a set range. The furnace body is provided with an infrared temperature measurement mechanism 7 for monitoring the temperature of the arc 32, and an observation window 17 for observing the production status of the nanopowder within the furnace body.

[0046] In the embodiment, a pneumatic ball valve 11 is provided on one end of the pipeline 10 close to the powder collecting tank 24; preferably, a pneumatic ball valve 11 is provided on the powder inlet pipe of the powder collecting tank 24, and the powder inlet pipe is connected to the pipeline 10. The pipeline 10 can be connected to multiple powder inlet pipes to ensure continuous production.

[0047] Preferably, the powder collecting tank 24 and the furnace body are provided with explosion-proof ports 8 to avoid explosions caused by excessive temperature or entry of air; preferably, the furnace door 31, the furnace body, the exhaust pipe 10 and the powder collecting tank 24 are provided with a cooling interlayer 14, and cooling water circulates in the interlayer to ensure the cooling effect of the vaporized base material and the formation of nanopowders; before processing, the furnace door 31 and the valves connecting the furnace body to the outside are closed first, so that the furnace body, the powder collecting tank 24 and the vacuum exhaust pipe 10 form a closed chamber together; then the vacuum exhaust component 16 starts to evacuate the entire chamber, and when the interior of the chamber reaches the set vacuum environment, argon gas is started to be filled into the furnace door 31, the interior of the furnace body, the plasma gun 5 and the blowing component 3 to avoid the entry of air and ensure the vaporization environment in the furnace body. At the same time, the argon gas filled in is used as a carrier gas to blow the vaporized base material to the tail of the furnace body.

[0048] Several aeration points 34 are provided within the furnace. The airflow created by the aeration of the furnace prevents the vaporized parent material from approaching the inner wall of the furnace and adsorbing on it. The protective gas blown out from the aeration points 34 propels the vaporized parent material toward the rear of the furnace, preventing it from being adsorbed on the furnace and causing material waste.

[0049] The furnace body is provided with a furnace door 31, and a ventilation isolation layer 33 is laid on the furnace door 31 and the inner wall of the furnace body. The airflow at the inflation point 34 passes through the stainless steel mesh and blows into the furnace body cavity; the ventilation isolation layer 33 is a stainless steel mesh layer or a bubble film, and the surface of the stainless steel mesh layer or the bubble film is a smooth surface, which is convenient for reducing the adsorption of the vaporized base material on the stainless steel mesh layer or the bubble film.

[0050] Preferably, the ventilation isolation layer 33 is detachably arranged on the inner wall of the furnace body. After the ventilation isolation layer 33 is removed, it is convenient to clean the furnace body, and the protective gas blown out from the furnace body inflation point 34 has the effect of dispersing the airflow and uniforming the wind, and has a heat-insulating effect on the inner wall of the furnace body, further preventing the vaporized base material from being adsorbed on the inner wall of the furnace body, and has an isolating and protective effect on the inner wall of the furnace body. The ventilation isolation layer 33 can be replaced after multiple uses.

[0051] Thus, three layers of protection are achieved. The first layer of protection is the protective gas blown out from the inflation point 34, that is, the protective gas between the inflation point 34 and the ventilation isolation layer 33; the second layer of protection is the protective gas after uniform wind passing through the ventilation isolation layer 33, and the protective gas is directly blown into the furnace body cavity; the third layer of protection, the ventilation isolation layer 33 itself, isolates and protects the inner wall of the furnace body, effectively preventing the vaporized base material from being adsorbed on the inner wall of the furnace body.

[0052] The blowing assembly 3 includes an air inlet pipe and a blowing nozzle. The air inlet pipe is passed through the furnace door 31 and is sealed with the furnace door 31. A blowing nozzle is provided at the inner end of the air pipe, and the blowing nozzle is arranged above the opening of the crucible 4. The outer end of the air inlet pipe is connected to a high-pressure gas source. An electromagnetic valve is provided on the air inlet pipe. The protective gas blown out of the blowing nozzle is used as a carrier gas to transport the vaporized base material to the tail of the furnace body.

[0053] Three rows of blowing nozzles are arranged in an upper and lower distribution to blow air to the upper and lower parts of the opening of the crucible 4 respectively. Blowing air toward the lower part of the opening of the crucible 4 can prevent the vaporized base material from being adsorbed on the outer surface of the crucible 4 and its surroundings. Two rows are arranged above the opening of the crucible 4 to prevent the vaporized base material from passing through the protective gas layer blown out by the blowing component 3 and spreading upward, thereby preventing the vaporized base material from being adsorbed on the inner wall of the furnace body due to excessive dispersion.

[0054] Alternatively, at least two groups of air blowing assemblies 3 are provided, with one group positioned below the opening of the crucible 4 and the remaining groups positioned vertically and horizontally above the opening of the crucible 4. Preferably, at least 2-5 groups of air blowing assemblies 3 are provided. More preferably, in this embodiment, at least three groups of air blowing assemblies 3 are provided, with one group positioned below the opening of the crucible 4 and the remaining two groups positioned vertically and horizontally above the opening of the crucible 4. Positioning the air blowing assemblies 3 below the opening of the crucible 4 prevents vaporized parent material from adsorbing on the outer surface of the crucible 4 and its surroundings. Positioning the two groups above the opening of the crucible 4 prevents vaporized parent material from passing through the protective gas layer blown by the air blowing assemblies 3 and dispersing upward, thereby preventing excessive dispersion from adsorbing on the inner wall of the furnace body.

[0055] Two sets of powder collecting devices are provided to ensure uninterrupted and continuous production. When one of the powder collecting devices is full, it can be switched to the other powder collecting device for collection through a valve. In order to ensure the vacuum degree of the powder collecting device, a vacuum pipe 22 is provided in the powder collecting tank 24. The vacuum pipe 22 is connected to the vacuum exhaust component 16. A valve is provided on the vacuum pipe 22. Before replacement, the powder collecting device is vacuumed to prevent the powder collecting device from carrying air and affecting the production environment of the nano powder in the furnace body.

[0056] The wire feeding device 1 includes a shell, a wire feeder, a bracket and a roller. The shell is provided with a bracket. The roller is arranged in the shell through a fixed axis. The wire feeder is arranged in the shell. The wire feeding device 1 is connected to the furnace body through a vacuum tube. The wire feeder in a vacuum environment continuously feeds the base material welding wire from the vacuum tube to the chamber crucible 4. A valve is provided on the vacuum tube. The vacuum tube is connected to the wire inlet pipe 21 on the furnace body. A vacuum tube 22 is provided on the shell. The vacuum tube 22 is connected to the vacuum exhaust component 16. A valve is provided on the vacuum tube 22.

[0057] When continuously adding raw materials, first close the valves on the wire feeder and the vacuum tube, then open the shell to replace or continue to add raw materials. After adding, close the shell and seal it, open the valve on the vacuum tube 22, and use the vacuum exhaust component 16 to evacuate the inside of the shell until the set vacuum degree is reached. After reaching the set value, close the valve on the vacuum tube 22, open the valve on the vacuum tube and the wire feeder, and start conveying raw materials into the furnace body. Continuous addition of raw materials without stopping the machine facilitates continuous production and processing, and prevents raw materials from contacting the air and affecting the production quality of nanopowder.

[0058] The furnace body is also provided with a secondary feeding assembly 18, which includes a feeding chamber, a drive motor 12, a solenoid valve and a guide pipe 30. A number of feeding chambers are provided in the feeding chamber, and the feeding chamber is driven to rotate by the drive motor 12 above the feeding chamber. The solenoid valve is arranged at the outlet of the feeding chamber, and the lower end of the solenoid valve is connected to the guide pipe 30. The guide pipe 30 guides the raw materials into the crucible 4. The feeding chamber is connected to the vacuum exhaust assembly 16 through a vacuum exhaust pipe 22, and a valve is provided on the vacuum exhaust pipe 22.

[0059] When replacing raw materials, first close the solenoid valve and seal it, then open the feeding chamber above, add raw materials to the feeding chamber, close the feeding chamber after adding, and open the valve on the vacuum pipe 22. The vacuum pumping assembly 16 evacuates the feeding chamber. When the set vacuum degree is reached, close the valve on the vacuum pipe 22, and then open the solenoid valve again. This completes the replacement or addition of the raw materials, avoids the raw materials from carrying air, and ensures the vacuum degree of the furnace body and the processing quality of the nano powder. Before processing, the feeding chamber can be evacuated separately or together with the furnace body.

[0060] During use, first, cooling water is circulated to the cooling interlayer 14 of the furnace door 31, the furnace body, the exhaust pipe 10 and the powder collecting tank 24, and the base material welding wire is added to the wire feeding device 1, and the second and third raw materials are added to the secondary feeding component 18. The raw materials in the secondary feeding component 18 can also be added after the base material welding wire is vaporized for a period of time. Then, the furnace door 31 and the valve connecting to the outside world in the furnace body are closed, so that the furnace body, the powder collecting tank 24 and the vacuum exhaust pipe 10 form a closed chamber together; then the vacuum exhaust component 16 starts to evaporating the entire cavity. The chamber is evacuated, and when the interior of the chamber reaches the set vacuum environment, argon gas is filled into the furnace door 31, the interior of the furnace body, the plasma gun 5 and the blowing assembly 3 to prevent the entry of air and ensure the vaporization environment in the furnace body. The first plasma gun 19 is started, and then the second plasma gun 20 is started. When the temperature in the crucible 4 reaches the set temperature, the wire feeding device 1 starts to feed the base material welding wire into the furnace body. The base material is vaporized in the crucible 4, and the vaporized base material is blown to the tail of the furnace body by the filled argon as a carrier gas and sent to the powder collecting tank 24.

[0061] The equipment structure of the present invention is cleverly designed, and the various devices or components are combined with each other to ensure the vacuum degree of the equipment production and processing, reduce the contact between raw materials and air or oxygen, ensure the production quality of nano powder, and facilitate continuous and uninterrupted production.

[0062] The above are preferred embodiments of the present invention and the technical principles used therein. For those skilled in the art, any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, are within the scope of protection of the present invention.

Claims

1. An apparatus for preparing nanopowders by plasma irradiation, comprising a furnace, a powder collecting device, a vaporizing device, and a wire feeding device, wherein a crucible is disposed within the furnace, the vaporizing device is disposed on the furnace and above the crucible, the powder collecting device is disposed at the rear of the furnace via a pipe, and the wire feeding device is disposed outside the furnace and feeds a base material welding wire into the furnace, characterized in that: The vaporization device includes at least two plasma guns, the plasma guns are connected to the negative electrode, and the crucible is connected to the positive electrode to generate a high-temperature arc between the two. The plasma guns are each provided with a handwheel for adjusting the up and down movement of the plasma guns. The base material welding wire is vaporized by the high-temperature arc. The vaporized base material is blown through the vaporization device and the horizontal blowing assembly above the crucible opening to the powder collection device for collection; The blowing assembly includes an air inlet pipe and a blowing nozzle. The air inlet pipe is provided on the furnace door. The inner end of the air pipe is provided with a blowing nozzle, which is arranged above the crucible opening. The outer end of the air inlet pipe is connected to a high-pressure air source. The air inlet pipe is provided with a solenoid valve. The blowing components are provided in at least two groups, one of which is provided below the crucible opening, and the remaining groups are provided above the crucible opening in an upper and lower distributed manner; Several inflation points are arranged in the furnace body; The furnace body is provided with a furnace door, and a ventilation isolation layer is laid on the furnace door and the inner wall of the furnace body. The airflow at the inflation point passes through the stainless steel mesh and blows into the furnace body cavity; the ventilation isolation layer is a stainless steel mesh layer or a bubble film.

2. The device for preparing nanopowder by plasma irradiation according to claim 1, characterized in that: It also includes a vacuum glove box, a vacuum exhaust component and an operating platform. The vacuum glove box is arranged below the powder collection device. The vacuum exhaust component is connected to the pipeline through a vacuum pipe. The furnace body, wire feeding component and control cabinet are arranged on the operating platform.

3. The device for preparing nanopowder by plasma irradiation according to claim 2, characterized in that: The powder collecting device includes a powder collecting tank, a filter element and a driving device. The powder collecting tank is provided with a powder inlet at the upper end and a discharge port at the lower end. The filter element is vertically fixed in the powder collecting tank. At least one brush is provided on the periphery of the filter element. The brush is driven by the driving device on the top of the powder collecting tank and rotates with the filter element as the axis. The brush is used to clean the powder on the inner wall of the powder collecting tank and the outer surface of the filter element. The lower end of the filter element is connected to an exhaust pipe, and the exhaust pipe is connected to a vacuum glove box.

4. The device for preparing nanopowder by plasma irradiation according to claim 2, characterized in that: The wire feeding device includes a shell, a wire feeder, a bracket and a roller. The shell is provided with a bracket, the roller is arranged in the shell through a fixed shaft, the wire feeder is arranged in the shell, the wire feeding device is connected to the furnace body through a vacuum tube, and the wire feeder in a vacuum environment continuously feeds the base material welding wire from the vacuum tube to the chamber crucible. A valve is provided on the vacuum tube, and a vacuum tube is provided on the shell. The vacuum tube is connected to the vacuum exhaust component, and a valve is provided on the vacuum tube.

5. The device for preparing nanopowder by plasma irradiation according to claim 2, characterized in that: The furnace body is also provided with a secondary feeding assembly, including a feeding chamber, a drive motor, a solenoid valve and a guide pipe. The feeding chamber is provided with several feeding cavities, which are driven to rotate by the drive motor above the feeding chamber. The solenoid valve is arranged at the outlet of the feeding chamber, and the lower end of the solenoid valve is connected to the guide pipe. The guide pipe guides the raw materials into the crucible. The feeding chamber is connected to the vacuum exhaust assembly through a vacuum exhaust pipe, and a valve is provided on the vacuum exhaust pipe.

6. The device for preparing nanopowder by plasma irradiation according to claim 3, characterized in that: A dust filter is vertically provided on the pipeline, and the dust filter is connected to the vacuum extraction component through a vacuum extraction pipe; Or a pneumatic ball valve is provided on one end of the pipeline close to the powder collecting tank; Or the pipeline is further provided with a branch pipe, and the branch pipe is provided with a resistance vacuum gauge, a sensor and a pressure gauge; Or the powder collecting tank and the furnace body are both provided with explosion-proof openings; Or the furnace door, furnace body, pipeline and powder collecting tank are all provided with cooling interlayers, and cooling water circulates in the interlayers.

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