Plasma ultrasonic generator and ultrasonic atomization pulverizing device

Abstract

The plasma ultrasonic generator comprises a shell, the shell is provided with a containing cavity and a discharging opening formed in the bottom end of the containing cavity, and a feeding pipe used for introducing raw materials is arranged in the shell; the gas inlet pipe is arranged on the periphery of the feeding pipe in a sleeving manner, and a first gas inlet channel used for introducing central gas is formed between the gas inlet pipe and the feeding pipe; a second gas inlet channel for introducing protective gas is formed between the gas inlet pipe and the shell; the coil is arranged in the shell, and high-frequency current is introduced into the coil to generate a magnetic field, so that the central gas is ionized to form plasma; the plasma melts the raw materials to form liquid drops; the ultrasonic device is arranged in the shell and located at the bottom of the shell. The ultrasonic device reduces the particle size of the droplets. Compared with the prior art, the prepared powder is small in particle size.

Description

Technical Field

[0001] The present invention relates to the field of preparation of powder materials, and particularly to a plasma ultrasonic generator and an ultrasonic atomization powder-making device. Background Art

[0002] The 3D printing method can manufacture die parts with complex shapes and internal structures by layer-by-layer stacking of powdered materials, breaking through the limitations of traditional processing methods. This improvement in design freedom makes the manufacturing of die-casting molds more precise and efficient, meeting the requirements of modern manufacturing for high-precision and high-quality die-casting molds. The commonly used particle size of 3D printing powder is 15 - 53 um. Currently, methods such as electrode induction gas atomization powder making, plasma rotating electrode powder making, plasma spheroidization, and plasma wire powder making are commonly used to prepare 3D printing powder.

[0003] The principle of the plasma spheroidization method is as follows: Utilizing the high-temperature environment of thermal plasma, the carrier gas feeds irregularly shaped powder into the high-temperature plasma. The powder particles quickly absorb heat and then the surface (or the whole) melts, and under the action of surface tension, they condense and polymerize into spherical droplets. After entering the cooling chamber, they are rapidly cooled and solidified to fix the spherical shape, thereby obtaining spherical powder. This method can only spheroidize non-spherical irregular powder and cannot change the powder particle size.

[0004] The principle of the plasma wire powder making method is to feed metal wire raw materials at a certain rate through a special feeding mechanism. Under the action of the focused plasma jet generated by multiple symmetrically installed plasma torches at the top of the furnace body, the raw materials are quickly dispersed into ultra-fine droplets or aerosol, and during the deposition process, heat exchange occurs with the inert gas used for cooling, and near-spherical powder is obtained after solidification. This method uses plasma to melt the wire into droplets, and forms a high-pressure plasma jet through compressed inert gas to break the droplets into spherical powder. The raw material of this method is metal wire, and the cost of metal wire raw materials is relatively high. Moreover, this method requires auxiliary equipment such as compressors to compress the inert gas into high-pressure gas for breaking the droplets, resulting in high energy consumption and large gas consumption.

[0005] However, the powder particles produced by the electrode induction gas atomization powder making method (EIGA) and the plasma rotating electrode powder making method (PREP) have large particle sizes. When used as commercial 3D printing powder, more than half of the large-particle-size (above 53 um) powder will be scrapped, causing a large amount of waste.

[0006] Therefore, it is necessary to improve the existing 3D printing powder preparation technology. Summary of the Invention

[0007] The first problem to be solved by the present invention is to provide a plasma ultrasonic generator according to the above technical status, which can be used for powder preparation and the obtained powder particles have small particle sizes.

[0008] The second problem to be solved by the present invention is to provide an ultrasonic atomization powder making device applying the above-mentioned plasma ultrasonic generator in view of the above technical status quo.

[0009] The solution adopted by the present invention to solve the above first technical problem is: a plasma ultrasonic generator, including a housing, the housing having a cavity and a discharge port provided at the bottom end of the cavity, characterized in that: a feed pipe for introducing raw materials is provided in the housing;

[0010] An intake pipe, sleeved on the outer periphery of the feed pipe, a first intake channel for introducing central gas is formed between the intake pipe and the feed pipe; a second intake channel for introducing protective gas is formed between the intake pipe and the housing;

[0011] A coil, provided in the housing, the coil passing a high-frequency current to generate a magnetic field, ionizing the central gas to form a plasma; the plasma melting the raw materials to form droplets; and

[0012] An ultrasonic device, provided in the housing and located at the bottom of the housing; the ultrasonic device reducing the particle size of the droplets.

[0013] Preferably, the raw materials are one or more of large particle waste materials produced by using the EIGA and PREP methods for powder making, and irregular large particle powders crushed by mechanical methods. The raw material cost is low.

[0014] In order to reduce pollution, preferably, the ultrasonic device is provided on the outer periphery of the cavity.

[0015] In order to increase the energy utilization rate of the ultrasonic wave, preferably, the ultrasonic device is provided at the bottom of the cavity.

[0016] Preferably, the central gas is argon.

[0017] Preferably, the protective gas is a mixed gas of argon and hydrogen. The mixed gas of argon and hydrogen in proportion can isolate the high-temperature plasma from the components. In addition, hydrogen can affect plasma characteristics such as temperature, electron density, etc.

[0018] In order to take away the heat generated by the plasma and thus protect the components, preferably, a cooling pipe for introducing cooling water is provided on the housing.

[0019] The solution adopted by the present invention to solve the above second technical problem is: an ultrasonic atomization device applying the above-mentioned plasma ultrasonic generator, characterized in that: including:

[0020] A cooling device, provided at the bottom of the plasma ultrasonic generator, the cooling device cooling the droplets generated by the plasma ultrasonic generator to form powder particles by cooling the droplets;

[0021] The first material tank is arranged at the bottom of the cooling device and is used for collecting the cooled powder particles; and

[0022] A vacuum device, the air inlet of which is connected to the air outlet of the cooling device, and the vacuum device is provided with an exhaust port for discharging gas outwards.

[0023] Preferably, the particle size of the powder particles is 15 - 53 um.

[0024] Preferably, the ultrasonic atomization device further includes a filtering device arranged between the vacuum device and the cooling device, and a second material tank for storing waste is arranged at the bottom of the filtering device.

[0025] Preferably, the ultrasonic atomization device further includes a feeding device and an air inlet pipe located at the top of the plasma ultrasonic generator; the discharge hole of the feeding device is connected to the feeding port of the feeding pipe; the air inlet pipe is used for introducing a protective gas into the second air inlet channel and introducing a central gas into the first air inlet channel.

[0026] Compared with the existing method, the advantages of the present invention are as follows: A first air inlet channel for introducing a central gas is formed between the air inlet pipe and the feeding pipe of the plasma ultrasonic generator; a second air inlet channel for introducing a protective gas is formed between the air inlet pipe and the housing; the central gas is ionized to form plasma. Since the plasma has a relatively high temperature, the plasma melts the raw material to form droplets. Then, under the action of the ultrasonic vibration of the ultrasonic device, the droplets are broken, so that the particle size of the droplets is reduced. The droplets with reduced particle size flow out of the plasma ultrasonic generator from the discharge port at the bottom end of the cavity. After the droplets are cooled, solid powder particles are obtained. Since the particle size of the droplets is small, the particle size of the prepared powder particles is also small, realizing refinement; and, the particle size of the powder particles is inversely proportional to the surface energy. Since the plasma temperature is high, the superheat degree of the droplets is high, and more energy can be converted into surface energy, which is beneficial to the reduction of the particle size of the powder particles. The ultrasonic vibration converts the mechanical energy generated by the ultrasonic device into the surface energy of the powder. The greater the surface energy, the finer the powder particles; in addition, the droplets are broken into small particle sizes by ultrasonic waves instead of by high-pressure gas, so there is no need to compress the inert gas, and there is no need for additional supporting equipment such as compressors and screw machines, and the production cost is low. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of the plasma ultrasonic generator in Embodiment 1;

[0028] Figure 2 It is a schematic structural diagram of the ultrasonic atomization device in Embodiment 1;

[0029] Figure 3 It is a schematic structural diagram of the plasma ultrasonic generator in Embodiment 2. Detailed Embodiments

[0030] The present invention will be further described in detail below in conjunction with the embodiments with reference to the accompanying drawings.

[0031] Embodiment 1

[0032] As Figure 1-2 shown, it is a preferred embodiment of the present invention.

[0033] As Figure 1 shown, a plasma ultrasonic generator 100 includes a housing 15, an intake pipe, a coil 4, and an ultrasonic device 5.

[0034] The housing 15 has a cavity 100a and a discharge port 7 provided at the bottom end of the cavity 100a. A feed pipe 1 for introducing raw materials is provided inside the housing 15; a cooling pipe 17 for introducing cooling water is provided on the housing 15.

[0035] The intake pipe is sleeved on the outer periphery of the feed pipe 1. A first intake channel 2 for introducing central gas is formed between the intake pipe and the feed pipe 1; a second intake channel 3 for introducing protective gas is formed between the intake pipe and the housing 15; wherein, the central gas is argon, and the protective gas is a mixed gas of argon and hydrogen.

[0036] The coil 4 is provided inside the housing 15. The coil 4 is energized with high-frequency current to generate a magnetic field, causing the central gas to be ionized to form plasma; the plasma melts the raw materials to form droplets 16; and

[0037] The ultrasonic device 5 is provided inside the housing 15 and is located at the bottom of the housing 15 and on the outer periphery of the cavity 100a. The ultrasonic device 5 is not in direct contact with the droplets 16 and is not likely to cause contamination; the ultrasonic device 5 reduces the particle size of the droplets 16.

[0038] As Figure 2 shown, this embodiment also provides an ultrasonic atomization device applying the above-mentioned plasma ultrasonic generator 100. The ultrasonic atomization device includes a cooling device 6, a first material tank 14, a vacuum device 8, a filtering device 10, a second material tank 11, a feeding device 12, and an intake pipe 13.

[0039] The cooling device 6 is provided at the bottom of the plasma ultrasonic generator 100. The cooling device 6 cools the droplets 16 generated by the plasma ultrasonic generator 100, causing the droplets 16 to be cooled to form powder particles;

[0040] The first material tank 14 is provided at the bottom of the cooling device 6 and is used to collect the cooled powder particles; and

[0041] The intake port of the vacuum device 8 is connected to the outlet of the cooling device 6. The vacuum device 8 is provided with an exhaust port 9 for discharging gas outward.

[0042] The filtering device 10 is provided between the vacuum device 8 and the cooling device 6. A second material tank 11 for storing waste materials is provided at the bottom of the filtering device 10.

[0043] The feeding device 12 and the intake pipe 13 are located at the top of the plasma ultrasonic generator 100; the discharge hole of the feeding device 12 is connected to the inlet of the feeding pipe 1; the intake pipe 13 is used to introduce a protective gas into the second intake channel 3 and introduce a central gas into the first intake channel 2.

[0044] The working process of this embodiment is as follows:

[0045] The vacuum device 8 evacuates the gas in the ultrasonic atomization device and introduces a protective gas; then, a protective gas is introduced into the second intake channel 3 from the intake pipe 13 and a central gas is introduced into the first intake channel 2, and a high-frequency current is passed through the coil 4 to generate a magnetic field, and the central gas is ionized to form a plasma; raw materials are fed into the feeding pipe 1 through the feeding device 12 to the cavity of the housing 15, the plasma melts the raw materials to form droplets 16, and the ultrasonic device 5 breaks the droplets 16 to reduce the particle size of the droplets 16; the droplets 16 with a small particle size enter the cooling device 6 through the discharge port 7, and the droplets 16 are cooled to form powder particles; and enter the first storage tank 14; the particle size of the powder particles is 15 - 53 um. The gas flow in the cooling device 6 enters the filtering device 10, and at the same time, some powder particles that are too small to enter the first storage tank 14 flow into the filtering device 10 with the gas flow, the filtered waste gas flows through the vacuum device 8 and is discharged from the exhaust port 9, and the solid waste enters the second storage tank 11.

[0046] Embodiment 2

[0047] As Figure 3 shown, the difference between this embodiment and Embodiment 1 is that: the ultrasonic device 5 is arranged at the bottom of the cavity 100a, and the contact between the droplet 16 and the ultrasonic device 5 is closer, which is convenient for breaking the droplet 16.

Claims

1. A plasma ultrasonic generator (100), comprising a housing (15), the housing (15) having a cavity (100a) and a discharge port (7) provided at the bottom end of the cavity (100a), characterized in that: A feed pipe (1) for introducing raw materials is provided inside the housing (15). An intake pipe, sleeved around the outer periphery of the feed pipe (1), forms a first intake passage (2) for introducing central gas between the intake pipe and the feed pipe (1); a second intake passage (3) for introducing protective gas is formed between the intake pipe and the housing (15). A coil (4) is provided inside the housing (15). The coil (4) is energized with high-frequency current to generate a magnetic field, ionize the central gas to form plasma, and melt the raw materials with the plasma to form droplets (16); and An ultrasonic device (5) is provided inside the housing (15). The ultrasonic vibration of the ultrasonic device (5) reduces the particle size of the droplets (16).

2. The plasma ultrasonic generator (100) according to claim 1, characterized in that: The ultrasonic device (5) is provided on the outer periphery of the cavity (100a).

3. The plasma ultrasonic generator (100) according to claim 1, characterized in that: The ultrasonic device (5) is provided at the bottom of the cavity (100a).

4. The plasma ultrasonic generator (100) according to claim 1, characterized in that: The central gas is argon.

5. The plasma ultrasonic generator (100) according to claim 1, characterized in that: The protective gas is a mixed gas of argon and hydrogen.

6. The plasma ultrasonic generator (100) according to claim 1, wherein: A cooling pipe (17) for introducing cooling water is provided on the housing (15).

7. An ultrasonic atomization device applying the plasma ultrasonic generator (100) according to any one of claims 1-6, characterized in that: Comprising: A cooling device (6) is provided at the bottom of the plasma ultrasonic generator (100). The cooling device (6) cools the droplets (16) generated by the plasma ultrasonic generator (100) to form powder particles. A first material tank (14) is provided at the bottom of the cooling device (6) and is used for collecting the cooled powder particles; and A vacuum device (8), with its intake port connected to the outlet of the cooling device (6). The vacuum device (8) is provided with an exhaust port (9) for discharging gas outward.

8. The ultrasonic atomization device according to claim 7, characterized in that: The particle size of the powder particles is 15 - 53 μm.

9. The ultrasonic atomization device according to claim 8, wherein: The ultrasonic atomization device further includes a filtering device (10) provided between the vacuum device (8) and the cooling device (6). A second material tank (11) for storing waste is provided at the bottom of the filtering device (10).

10. The ultrasonic atomization device according to claim 8, characterized in that: The ultrasonic atomization device further includes a feeding device (12) and an intake pipe (13) located at the top of the plasma ultrasonic generator (100). The discharge hole of the feeding device (12) is connected to the intake port of the feed pipe (1). The intake pipe (13) is used for introducing protective gas into the second intake passage (3) and introducing central gas into the first intake passage (2).

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