Novel double-circular-seam atomizer and atomizing device

Abstract

The invention belongs to the technical field of powder metallurgy, and discloses a novel double-circular-seam atomizer and an atomizing device.The novel double-circular-seam atomizer comprises an atomizer base body, a vertically-through melt channel is formed in the middle of the atomizer base body and used for allowing a flow guide nozzle to penetrate through, and the atomizer base body is provided with a cavity coaxial with the melt channel and a circular-seam spraying hole; the cavity is used for inputting high-pressure gas, and the circular seam spraying hole communicates with the cavity and is used for spraying out the high-pressure gas to form high-speed gas flow so as to break metal melt liquid flow flowing out of the flow guide nozzle. The number of the circular seam spraying holes is two, the two circular seam spraying holes are the first circular seam spraying hole and the second circular seam spraying hole, the second circular seam spraying hole surrounds the first circular seam spraying hole from the outer side of the first circular seam spraying hole, and on any longitudinal section plane of the atomizer base body, the jet flow center lines of the second circular seam spraying hole and the first circular seam spraying hole intersect at one point; the melt liquid flow crushing effect can be improved, the diffusion angle of metal liquid drops is increased, formation of large particles is reduced, and metal powder with smaller particle size and better sphericity degree is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of powder metallurgy, and in particular to a novel double annular gap atomizer and an atomizing device. Background Art

[0002] Inert gas atomization is a commonly used method for producing metal powders. It has the advantages of low oxygen content, high fine powder yield, and good sphericity. It is widely used in the production of ultrafine powders such as metal 3D printing, powder metallurgy, and cold spraying.

[0003] In the process of producing metal powder by inert gas atomization, the molten metal obtained by smelting is usually passed through a guide nozzle to form a melt flow, and then a high-speed inert gas flow is sprayed to the melt flow by an atomizer to break the melt flow into metal droplets, and the metal droplets are cooled to obtain metal powder. At present, the commonly used atomizers are mostly single annular gap atomizers, and their structure includes an annular cavity and an annular gap spray hole connected thereto. During operation, high-pressure inert gas is input into the annular cavity and sprayed out from the annular gap spray hole to form a high-speed inert gas flow.

[0004] However, there are some problems with the existing single annular gap atomizer. First, the single annular gap atomizer has a poor effect on the breakup of the melt flow, and it is difficult to effectively disperse the melt flow into fine droplets. Secondly, the diffusion angle of the broken metal droplets is small, which makes it easy for the droplets to collide before they are completely cooled, forming large particles (satellite balls). These problems ultimately make it difficult to obtain small-particle metal powders, and the sphericity of the metal powders is poor.

[0005] In addition, the structure of the single annular gap atomizer limits its effect on the melt flow. Since there is only one annular gap nozzle, the contact area and action time of the airflow and the melt flow are limited, making it difficult to achieve a more efficient atomization process.

[0006] In view of the above problems, the existing technology needs to be improved urgently. Summary of the invention

[0007] The purpose of the present application is to provide a novel double annular gap atomizer and atomizing device, which can improve the melt flow breakup effect, increase the metal droplet diffusion angle, reduce the formation of large particles, and obtain metal powder with smaller particle size and better sphericity.

[0008] In the first aspect, the present application provides a novel double annular gap atomizer for atomizing a molten metal flow, comprising an atomizer base, a melt channel running through the base from top to bottom being provided in the middle of the atomizer base, the melt channel being used for a guide nozzle to pass through, the atomizer base being provided with a cavity and an annular gap spray hole coaxial with the melt channel, the cavity being used for inputting high-pressure gas, the annular gap spray hole being connected to the cavity, and being used for spraying the high-pressure gas to form a high-speed airflow to break up the molten metal flow flowing out of the guide nozzle; the annular gap spray hole being provided with two, namely a first annular gap spray hole and a second annular gap spray hole, the second annular gap spray hole surrounding the first annular gap spray hole from the outside of the first annular gap spray hole, and on any longitudinal cross-sectional plane of the atomizer base, the jet midlines of the second annular gap spray hole and the first annular gap spray hole intersect at one point.

[0009] The airflow ejected from the first annular gap spray hole preliminarily breaks up the molten metal flow, and the airflow ejected from the second annular gap spray hole further breaks up the molten metal flow, thereby increasing the contact area and action time between the airflow and the molten metal flow, improving the breakup effect of the molten metal flow, and reducing the size of the metal droplets; since the second annular gap spray hole is outside the first annular gap spray hole and the jet midlines of the two intersect at one point, the angle between the jet midline of the second annular gap spray hole and the axis of the melt channel is larger, which can increase the diffusion range of the metal droplets, reduce the probability of collision between the metal droplets, and reduce the formation of large particles; at the intersection point, the airflow rate increases, which can enhance the breakup effect and cooling effect, accelerate the cooling and solidification of the metal droplets, thereby reducing the probability of forming large particles after collision, and further reducing the formation of large particles; therefore, the novel double annular gap atomizer can improve the breakup effect of the molten metal flow, increase the diffusion angle of the metal droplets, reduce the formation of large particles, and obtain metal powders with smaller particle size and better sphericity.

[0010] Preferably, the angle between the jet centerline of the first annular gap spray hole and the axis of the melt channel is 25°-30° smaller than the angle between the jet centerline of the second annular gap spray hole and the axis of the melt channel.

[0011] By setting two annular gap nozzles and making their jet center lines at different angles with the axis of the melt channel, a complex airflow field is formed. The first annular gap nozzle has a smaller angle, which can generate a stronger shear force, which helps to initially break up the metal melt flow. The second annular gap nozzle has a larger angle, which can generate a larger range of vortices, further refine the metal powder, and disperse the metal droplets to a larger range, reducing the probability of collision between metal droplets. The difference in the angle between the two annular gap nozzles (25°-30°) is optimized. This design allows the two airflows to act on the metal melt flow at different positions and angles, thereby achieving a more uniform and efficient atomization process.

[0012] Preferably, the included angle between the jet centerline of the first annular gap spray hole and the axis of the melt channel is 30°-36°; the included angle between the jet centerline of the second annular gap spray hole and the axis of the melt channel is 55°-66°.

[0013] Preferably, the included angle between the jet centerline of the first annular gap spray hole and the axis of the melt channel is 33°, and the included angle between the jet centerline of the second annular gap spray hole and the axis of the melt channel is 60°.

[0014] Preferably, the first annular gap spray hole and the second annular gap spray hole are both Laval spray holes.

[0015] The use of Laval nozzles as the first annular nozzle and the second annular nozzle can significantly improve the atomization effect. The Laval nozzle has a special contraction-expansion structure that can accelerate the subsonic airflow to supersonic speed. During the atomization process, the Laval nozzle can generate a faster and more uniform airflow, thereby more effectively breaking up the metal melt flow.

[0016] Preferably, the cavity comprises a first cavity and a second cavity which are isolated from each other, the first annular gap spray hole is connected to the first cavity, and the second annular gap spray hole is connected to the second cavity.

[0017] Preferably, the rated outlet gas pressure of the first annular gap spray hole and the second annular gap spray hole is not greater than one atmosphere.

[0018] Preferably, the rated outlet gas pressures of the first annular gap spray hole and the second annular gap spray hole are both equal to one atmosphere.

[0019] Preferably, the rated pressure of the second cavity is greater than the rated pressure of the first cavity.

[0020] In a second aspect, the present application provides an atomization device, including the novel double-annular gap atomizer described above.

[0021] Beneficial effects: The novel double annular gap atomizer and atomizing device provided by the present application uses the airflow ejected from the first annular gap nozzle hole to preliminarily break up the molten metal flow, and then uses the airflow ejected from the second annular gap nozzle hole to further break up the molten metal flow, thereby increasing the contact area and action time between the airflow and the molten metal flow, improving the breakup effect of the molten metal flow, and reducing the size of the metal droplets; since the second annular gap nozzle hole is outside the first annular gap nozzle hole and the jet midlines of the two intersect at one point, the angle between the jet midline of the second annular gap nozzle hole and the axis of the melt channel is larger, which can increase the diffusion range of the metal droplets, reduce the probability of collision between the metal droplets, and reduce the formation of large particles; at the intersection point, the airflow rate increases, which can enhance the breakup effect and cooling effect, accelerate the cooling and solidification of the metal droplets, thereby reducing the probability of forming large particles after collision, and further reducing the formation of large particles; therefore, the novel double annular gap atomizer can improve the breakup effect of the molten metal flow, increase the diffusion angle of the metal droplets, reduce the formation of large particles, and obtain metal powders with smaller particle size and better sphericity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A longitudinal cross-sectional view of a novel double annular gap atomizer provided in an embodiment of the present application.

[0023] Figure 2 A schematic diagram of the structure of the atomization device provided in an embodiment of the present application.

[0024] Explanation of reference numerals: 1. atomizer base; 2. melt channel; 3. cavity; 301. first cavity; 302. second cavity; 4. annular gap spray hole; 401. first annular gap spray hole; 402. second annular gap spray hole; 100. novel double annular gap atomizer; 200. guide nozzle; 300. atomizing chamber; 400. smelting chamber; 500. smelting crucible; 600. tundish; 700. collector. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0026] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0027] In the manufacturing process of metal powder, inert gas atomization has become a widely used method because it can prepare metal powders with low oxygen content, high fine powder yield and good sphericity. This method shows great advantages in the production of ultrafine powders such as metal 3D printing, powder metallurgy and cold spraying. In traditional processes, most use single annular gap atomizers, which consist of an annular cavity and an annular gap nozzle connected to it. By inputting high-pressure inert gas into the annular cavity, the high-pressure gas is ejected from the nozzle to form a high-speed airflow, thereby breaking up the metal melt flow.

[0028] However, there are some problems that cannot be ignored in the single annular gap atomizer in the process of breaking up the melt flow and cooling the metal droplets. The airflow sprayed by the single annular gap atomizer is often difficult to fully break up the melt flow, resulting in a smaller diffusion angle for the metal droplets to form, which further causes a higher probability of droplets colliding and condensing into large particles before cooling. In this case, it is difficult to obtain metal powder with a smaller particle size and better sphericity, which directly affects the powder quality and subsequent processing performance.

[0029] In view of these problems, the present application proposes a novel double-annular gap atomizer.

[0030] Please refer to Figure 1 In some embodiments of the present application, a novel double annular gap atomizer 100 is used to atomize a molten metal flow, including an atomizer base 1, a melt channel 2 running through the upper and lower parts is provided in the middle of the atomizer base 1, the melt channel 2 is used for the guide nozzle 200 to pass through, the atomizer base 1 is provided with a cavity 3 (annular cavity) and an annular gap spray hole 4 coaxial with the melt channel 2, the cavity 3 is used to input high-pressure gas (generally inert gas), the annular gap spray hole 4 is connected to the cavity 3, and is used to spray high-pressure gas to form a high-speed airflow to break up the molten metal flow flowing out of the guide nozzle 200; there are two annular gap spray holes 4, namely a first annular gap spray hole 401 and a second annular gap spray hole 402, the second annular gap spray hole 402 surrounds the first annular gap spray hole 401 from the outside, and is located on any longitudinal cross-sectional plane of the atomizer base 1 (such as Figure 1 The plane where the image is located, the axis of the melt channel 2 is on this plane), the jet center line of the second annular gap spray hole 402 and the first annular gap spray hole 401 (that is, the central axis of the jet on the longitudinal section plane, such as Figure 1In the figure, straight line a is the jet center line of the first annular gap spray hole 401, and straight line b is the jet center line of the second annular gap spray hole 402) and they intersect at one point.

[0031] The airflow ejected from the first annular gap spray hole 401 preliminarily breaks up the metal melt flow, and the airflow ejected from the second annular gap spray hole 402 further breaks up the metal melt flow, thereby increasing the contact area and action time between the airflow and the melt flow, improving the breakup effect of the melt flow, and reducing the size of the metal droplets; since the second annular gap spray hole 402 is outside the first annular gap spray hole 401 and the jet center lines of the two intersect at one point, the angle between the jet center line of the second annular gap spray hole 402 and the axis of the melt channel 2 (hereinafter referred to as the airflow) is 1 / 400mm. The larger the impact angle), the greater the diffusion range of the metal droplets, the lower the probability of collision between the metal droplets, and the lower the formation of large particles; at the intersection point, the gas flow rate increases, which can enhance the crushing and cooling effects, accelerate the cooling and solidification of the metal droplets, thereby reducing the probability of forming large particles after collision, and further reducing the formation of large particles; therefore, the novel double annular gap atomizer 100 can improve the melt flow crushing effect, increase the metal droplet diffusion angle, reduce the formation of large particles, and obtain metal powders with smaller particle size and better sphericity.

[0032] In some preferred embodiments, the angle between the jet centerline of the first annular gap spray hole 401 and the axis of the melt channel 2 is 25°-30° smaller than the angle between the jet centerline of the second annular gap spray hole 402 and the axis of the melt channel 2 (i.e., the airflow angle of the jet of the first annular gap spray hole 401 is 25°-30° smaller than the airflow angle of the jet of the second annular gap spray hole 402).

[0033] By setting two annular gap spray holes 4 and making their jet center lines have different angles with the axis of the melt channel 2, a complex airflow field is formed. The first annular gap spray hole 401 has a smaller angle, which can generate a stronger shear force, which helps to initially break up the metal melt flow. The second annular gap spray hole 402 has a larger angle, which can generate a larger range of eddies, further refine the metal powder, and disperse the metal droplets to a larger range, reducing the probability of collision between metal droplets. The difference in the angle between the two annular gap spray holes 4 (25°-30°) is optimized. This design allows the two airflows to act on the metal melt flow at different positions and angles, thereby achieving a more uniform and efficient atomization process.

[0034] Furthermore, the included angle between the jet centerline of the first annular gap spray hole 401 and the axis of the melt channel 2 is 30°-36°; the included angle between the jet centerline of the second annular gap spray hole 402 and the axis of the melt channel 2 is 55°-66°.

[0035] The atomization effect is optimized by precisely controlling the angle between the jet centerline of the first annular gap spray hole 401 and the second annular gap spray hole 402 and the axis of the melt channel 2. The angle range of the first annular gap spray hole 401 is 30°-36°. This smaller angle allows the high-pressure gas to act more directly on the metal melt flow, improving the initial crushing efficiency. The angle range of the second annular gap spray hole 402 is 55°-66°. This larger angle can further disperse and refine the metal droplets after the initial crushing, and also helps to control the shape of the atomization area. The difference in the angle between the two annular gap spray holes 4 is about 25°-30°. This design can create a multi-level atomization effect. The first annular gap spray hole 401 of the inner layer is mainly responsible for the initial crushing, while the second annular gap spray hole 402 of the outer layer further refines the droplets and controls the atomization area. This combination can optimize the size distribution and morphology of the powder particles while ensuring the atomization efficiency.

[0036] In the novel double annular gap atomizer 100 of the present application, the angle between the jet centerline of the first annular gap spray hole 401 and the axis of the melt channel 2 can be adjusted within the range of 30°-36°. For example, it can be set to 30°, 32°, 33°, 34° or 36°. The selection of this angle range is verified by experiments. When the angle is less than 30°, the initial crushing effect of the high-pressure gas on the melt flow may not be ideal; and when the angle is greater than 36°, the efficiency of the initial crushing may be reduced.

[0037] The angle between the jet centerline of the second annular gap spray hole 402 and the axis of the melt channel 2 can be adjusted within the range of 55°-66°. For example, it can be set to 55°, 60°, 63° or 66°. This larger angle range can effectively further disperse and refine the metal droplets after the initial crushing of the first annular gap spray hole 401. When the angle is less than 55°, the effect of the second crushing may not be fully exerted; and when the angle is greater than 66°, the atomization area may be too diffuse, affecting the collection efficiency of the powder.

[0038] For example, in a specific embodiment, the angle between the jet centerline of the first annular gap spray hole 401 and the axis of the melt channel 2 is 33°, and the angle between the jet centerline of the second annular gap spray hole 402 and the axis of the melt channel 2 is 60°. The 33° angle setting of the first annular gap spray hole 401 enables the high-pressure gas to act more directly on the metal melt flow, providing a preliminary crushing force. The 60° angle setting of the second annular gap spray hole 402 can cover the metal droplets that have been preliminarily crushed in a larger range, further refining the particles. This angle configuration enables the jets of the two annular gap spray holes 4 to work effectively together. The smaller angle of the first annular gap spray hole 401 ensures direct impact on the metal melt, while the larger angle of the second annular gap spray hole 402 provides a wider coverage range. This design can not only improve the atomization efficiency, but also improve the particle size distribution and morphology of the metal powder.

[0039] Preferably, the first annular gap spray hole 401 and the second annular gap spray hole 402 are both Laval spray holes.

[0040] The use of Laval nozzles as the structure of the first annular gap nozzle 401 and the second annular gap nozzle 402 can significantly improve the atomization effect. The Laval nozzle has a special contraction-expansion structure, which can accelerate the subsonic airflow to supersonic speed. During the atomization process, the Laval nozzle can generate a faster and more uniform airflow, thereby more effectively breaking up the metal melt flow.

[0041] The structure of the Laval nozzle generally includes a contraction section, a throat section, and an expansion section. The contraction section accelerates the airflow from subsonic speed to sonic speed, the airflow at the throat reaches sonic speed, and the expansion section further accelerates the airflow to supersonic speed. In the present application, the first annular nozzle 401 and the second annular nozzle 402 can adopt different contraction ratios and expansion ratios to adapt to different airflow speed requirements. For example, the first annular nozzle 401 can adopt a smaller contraction ratio and expansion ratio to produce a relatively low supersonic airflow, which is mainly used for the initial crushing of the melt; while the second annular nozzle 402 can adopt a larger contraction ratio and expansion ratio to produce a higher-speed supersonic airflow for further refining the metal particles.

[0042] For example, the contraction ratio of the first annular gap spray hole 401 can be set to between 1.5:1 and 3:1, and the expansion ratio can be set to between 2:1 and 4:1; the contraction ratio of the second annular gap spray hole 402 can be set to between 2:1 and 4:1, and the expansion ratio can be set to between 3:1 and 6:1. This design allows the airflows generated by the two spray holes to form a gradient in speed and kinetic energy, which is conducive to gradually refining the metal melt and improving the atomization efficiency.

[0043] In practical applications, the design of the Laval nozzle also needs to consider factors such as gas pressure and temperature. For example, the throat area can be adjusted to adapt to different gas pressures to ensure that the ideal supersonic state can be achieved under various working conditions. In addition, the material selection of the Laval nozzle (i.e., the material of the atomizer substrate 1) is also very important. High-temperature resistant and corrosion-resistant alloy materials are usually used to ensure good performance and life in high-temperature and high-pressure working environments.

[0044] Among them, only one cavity 3 may be provided, so that the first annular gap spray hole 401 and the second annular gap spray hole 402 are both connected to the cavity 3 .

[0045] But more preferably, see Figure 1 The cavity 3 includes a first cavity 301 and a second cavity 302 which are isolated from each other. The first annular gap spray hole 401 is connected to the first cavity 301 , and the second annular gap spray hole 402 is connected to the second cavity 302 .

[0046] By setting up the first cavity 301 and the second cavity 302 which are isolated from each other and are connected to the first annular gap spray hole 401 and the second annular gap spray hole 402 respectively, the independent control of the high-pressure gas supply of the two annular gap spray holes 4 is realized. This design allows the air pressure and air volume of the first annular gap spray hole 401 and the second annular gap spray hole 402 to be adjusted separately, so that the atomization process can be controlled more accurately. For example, the speed and pressure of the inner and outer layers of air flow can be adjusted as needed to optimize the crushing effect of the metal melt. In addition, this independently controlled structure also provides greater flexibility for further optimizing the atomization process, such as adjusting the gas parameters according to different metal materials or powder particle size requirements. Through this design, the atomizer can better adapt to different atomization requirements, improve the atomization efficiency and the consistency of powder quality. At the same time, this structure also provides convenience for studying the influence of different air pressure combinations on the atomization effect, which helps to further improve the atomization technology.

[0047] In a specific implementation, the first cavity 301 and the second cavity 302 can adopt a variety of structural designs. For example, a partition can be set inside the atomizer base 1 to separate the original single cavity into two independent chambers. Another way is to open two independent cavities 3 on the atomizer base 1, each cavity 3 has its own gas input port (for example Figure 1 c in the figure is a gas input port, and each cavity 3 is evenly arranged with a plurality of gas input ports along the circumference to ensure uniform gas pressure in the cavity 3). Both designs can ensure that the first cavity 301 and the second cavity 302 are completely isolated to prevent gas cross-flow.

[0048] The communication between the first annular gap spray hole 401 and the first cavity 301, and the communication between the second annular gap spray hole 402 and the second cavity 302, can be achieved through precision machined channels. The design of these channels needs to take into account the flow characteristics of the gas flow to ensure that the gas can be evenly distributed throughout the annular gap spray hole 4. The cross-sectional area and shape of the channel can be optimized as needed to reduce gas flow resistance and energy loss.

[0049] Preferably, the rated outlet pressure of the first annular gap spray hole 401 and the second annular gap spray hole 402 (ie, the reference pressure at the outlet required to be reached during operation) is not greater than one atmosphere.

[0050] The novel double annular gap atomizer 100 is installed in the atomizing chamber 300 of the atomizing device for use. The pressure of the atomizing chamber 300 of the general atomizing device is maintained at one atmospheric pressure during operation. Controlling the outlet air pressure of the annular gap spray hole 4 to be no greater than one atmospheric pressure can suppress the generation of shock waves at the outlet, thereby avoiding the air flow velocity at the outlet from being reduced to subsonic speed and causing the temperature at the outlet to rise due to the generation of shock waves at the outlet (the reduction of air flow velocity will reduce the atomization efficiency, and the increase of temperature at the outlet will increase energy loss). In addition, the deflection of the air flow direction caused by the pressure difference at the outlet pressure is reduced. Specifically, controlling the rated outlet air pressure of the annular gap spray hole 4 to be no greater than one atmospheric pressure has the following advantages: first, it can prevent the reflux or splashing of the metal melt caused by excessive air flow pressure, thereby improving the stability and safety of the atomization process. Secondly, suppressing the generation of shock waves at the outlet, avoiding the air flow velocity at the outlet from being reduced to subsonic speed and causing the temperature at the outlet to rise due to the generation of shock waves at the outlet, thereby reducing the energy consumption in the atomization process and improving the atomization efficiency. By controlling the outlet air pressure of the annular gap spray hole 4 in this way, combined with the double annular gap design, the metal melt flow can be efficiently crushed and atomized, thereby producing a metal powder with higher quality and more uniform particle size distribution. This design can optimize energy utilization while ensuring the atomization effect, and improve the economy and environmental protection of the entire atomization process.

[0051] In the present application, the rated outlet pressure of the first annular gap spray hole 401 and the second annular gap spray hole 402 can be controlled to be no greater than one atmospheric pressure in a variety of ways. One possible implementation method is to control the outlet pressure of the spray hole by accurately adjusting the air pressure in the cavity 3. For example, a pressure sensor and a pressure regulating valve can be installed in the cavity 3 to ensure that the outlet pressure of the spray hole is always maintained within a range of no greater than one atmospheric pressure by real-time monitoring and adjusting the air pressure in the cavity 3.

[0052] Another possible implementation method is to control the outlet pressure by geometric design of the nozzle. For example, the expansion degree of the airflow in the nozzle can be affected by adjusting the contraction ratio and expansion ratio of the nozzle, thereby controlling the outlet pressure. In this case, the length ratio of the contraction section and the expansion section of the nozzle can be designed to be between 1:2 and 1:4 to achieve an ideal outlet pressure control effect.

[0053] In addition, it is also possible to consider using an adjustable nozzle structure to adjust the opening size of the nozzle in real time through mechanical or electronic control to achieve more precise outlet air pressure control. For example, a variable cross-section annular slit nozzle 4 can be designed to control the outlet air pressure by adjusting the width of the annular slit to meet different atomization requirements.

[0054] In a possible implementation manner, the rated outlet gas pressures of the first annular gap spray hole 401 and the second annular gap spray hole 402 are both equal to one atmosphere.

[0055] By setting the rated outlet pressure of the two annular gap spray holes 4 to be equal and equal to the atmospheric pressure, the following effects can be achieved: First, it ensures that the high-pressure gas ejected from the two annular gap spray holes 4 has the same outlet pressure, which is conducive to forming a stable airflow field, thereby improving the consistency and stability of the atomization effect. Secondly, setting the outlet pressure equal to the atmospheric pressure can avoid airflow turbulence, backflow and shock wave generation caused by excessive outlet pressure, which helps to form a more uniform and directional airflow and improve the crushing efficiency of the metal melt flow. Finally, this setting can also reduce energy consumption, because there is no need to compress the gas to a state higher than the atmospheric pressure, and it also reduces the impact and wear of the high-pressure gas on the equipment, extending the service life of the equipment.

[0056] Preferably, the rated pressure of the second cavity 301 (ie, the reference pressure required to be reached during operation) is greater than the rated pressure of the first cavity 302 .

[0057] The second cavity 302 is connected to the second annular gap spray hole 402 on the outside, and the first cavity 301 is connected to the first annular gap spray hole 401 on the inside. By increasing the rated pressure of the second cavity 302, the high-speed airflow sprayed from the annular gap spray hole 4 on the outside can have greater kinetic energy. This design helps to enhance the crushing effect of the metal melt flow, especially for further refinement of the melt droplets that have been preliminarily crushed by the annular gap spray hole 4 on the inside.

[0058] In practical applications, the rated pressure of the second cavity 302 may be 10%-50% higher than the rated pressure of the first cavity 301. For example, if the rated pressure of the first cavity 301 is 3 MPa, the rated pressure of the second cavity 302 may be set at 3.5 MPa. This pressure difference design may be adjusted according to specific atomization requirements and metal material properties.

[0059] The setting of the pressure difference not only affects the kinetic energy of the airflow, but also the speed and temperature of the airflow. Generally, higher pressure gas will produce faster airflow speed and lower airflow temperature when it is ejected. This characteristic can be used to further optimize the atomization process. For example, the higher pressure airflow in the outer layer can provide a stronger cooling effect, which helps to quickly solidify the metal droplets and reduce the collision and merging between the droplets.

[0060] In addition, the pressure difference design of the present application can also be combined with the angle design (referring to the airflow angle) of the first annular gap spray hole 401 and the second annular gap spray hole 402 to produce a better atomization effect. For example, the airflow with a lower pressure in the inner layer can cooperate with the first annular gap spray hole 401 with a smaller angle, which is mainly responsible for initial crushing and guiding the melt flow; while the airflow with a higher pressure in the outer layer cooperates with the second annular gap spray hole 402 with a larger angle, which is responsible for further crushing the droplets and increasing the diffusion angle of the droplets.

[0061] During the atomization process, the pressures of the first cavity 301 and the second cavity 302 can be precisely adjusted by an independent pressure control system. This independent control design allows operators to flexibly adjust the pressure ratio of the inner and outer gas flows according to actual needs to adapt to different metal materials and target particle size distributions. For example, for low-melting-point metals that are easy to atomize, the pressure difference between the two cavities can be appropriately reduced; while for high-melting-point, high-viscosity metals, the pressure difference can be increased to provide a stronger crushing ability.

[0062] refer to Figure 2 The present application provides an atomization device, including the novel double-annular gap atomizer 100 described above.

[0063] Specifically, the atomizing device further includes a smelting chamber 400 and an atomizing chamber 300. A smelting crucible 500 and a tundish 600 are arranged in the smelting chamber 400. A guide nozzle 200 is connected to the bottom of the tundish 600. The lower part of the guide nozzle 200 extends into the atomizing chamber 300. The novel double annular seam atomizer 100 is arranged in the atomizing chamber 300 and is sleeved on the lower part of the guide nozzle 200 through the melt channel 2. The novel double annular seam atomizer 100 is connected to an external gas supply device, and the external gas supply device delivers high-pressure gas (generally inert gas) to the cavity 3 of the novel double annular seam atomizer 100. Among them, a collector 700 is arranged at the lower end of the atomizing chamber 300 for collecting metal powder.

[0064] The working principle is as follows: the metal raw material is heated and melted into a metal melt in a smelting crucible 500, and then poured into a tundish 600. The metal melt flows from a guide nozzle 200 into an atomizing chamber 300 to form a metal melt liquid flow. A new double-annular gap atomizer 100 sprays a high-speed airflow toward the metal melt liquid flow for atomization to form metal powder, which eventually falls into a collector 700.

[0065] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0066] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A novel double annular gap atomizer for atomizing a metal melt flow, comprising an atomizer base (1), wherein a melt channel (2) penetrating from top to bottom is provided in the middle of the atomizer base (1), wherein the melt channel (2) is used for a guide nozzle to pass through, and the atomizer base (1) is provided with a cavity (3) and an annular gap spray hole (4) coaxial with the melt channel (2), wherein the cavity (3) is used for inputting high-pressure gas, and the annular gap spray hole (4) is connected with the cavity (3) and is used for spraying the high-pressure gas to form a high-speed airflow to break up the metal melt flow flowing out of the guide nozzle; characterized in that: The annular gap spray holes (4) are provided with two, namely a first annular gap spray hole (401) and a second annular gap spray hole (402), the second annular gap spray hole (402) surrounds the first annular gap spray hole (401) from the outside of the first annular gap spray hole (401), and on any longitudinal cross-sectional plane of the atomizer base (1), the jet midlines of the second annular gap spray hole (402) and the first annular gap spray hole (401) intersect at one point.

2. The novel double annular gap atomizer according to claim 1 is characterized in that: The included angle between the jet centerline of the first annular gap spray hole (401) and the axis of the melt channel (2) is 25°-30° smaller than the included angle between the jet centerline of the second annular gap spray hole (402) and the axis of the melt channel (2).

3. The novel double annular gap atomizer according to claim 2 is characterized in that: The included angle between the jet centerline of the first annular gap spray hole (401) and the axis of the melt channel (2) is 30°-36°; the included angle between the jet centerline of the second annular gap spray hole (402) and the axis of the melt channel (2) is 55°-66°.

4. The novel double annular gap atomizer according to claim 3 is characterized in that: The included angle between the jet centerline of the first annular gap spray hole (401) and the axis of the melt channel (2) is 33°, and the included angle between the jet centerline of the second annular gap spray hole (402) and the axis of the melt channel (2) is 60°.

5. The novel double annular gap atomizer according to claim 1 is characterized in that: The first annular gap spray hole (401) and the second annular gap spray hole (402) are both Laval spray holes.

6. The novel double annular gap atomizer according to claim 1 is characterized in that: The cavity (3) comprises a first cavity (301) and a second cavity (302) which are isolated from each other, the first annular gap spray hole (401) is in communication with the first cavity (301), and the second annular gap spray hole (402) is in communication with the second cavity (302).

7. The novel double annular gap atomizer according to claim 1 is characterized in that: The rated outlet gas pressure of the first annular gap spray hole (401) and the second annular gap spray hole (402) is not greater than one atmosphere.

8. The novel double annular gap atomizer according to claim 7, characterized in that: The rated outlet gas pressures of the first annular gap spray hole (401) and the second annular gap spray hole (402) are both equal to one atmospheric pressure.

9. The novel double annular gap atomizer according to claim 6, characterized in that: The rated pressure of the second cavity (302) is greater than the rated pressure of the first cavity (301).

10. An atomizing device, characterized in that: A novel double-annular gap atomizer (100) comprising the novel double-annular gap atomizer (100) as described in any one of claims 1 to 9.

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