Powder feeding device for conveying fine-particle powder

Abstract

The utility model discloses a powder feeding device for conveying fine particle powder, which comprises a powder storage bin, a powder feeding mechanism and a dispersion bin, the powder feeding mechanism is mounted at a discharge port of the powder storage bin, the dispersion bin is cylindrical, the top end of the dispersion bin is connected with an outlet of the powder feeding mechanism, and the powder feeding mechanism is mounted in the dispersion bin. The side cylindrical wall of the dispersion bin is provided with an air blowing port for blowing air to the inner cavity of the dispersion bin along the tangential direction of the side wall of the dispersion bin and a powder outlet for discharging powder; and the powder feeding mechanism is communicated with the top of the dispersion bin. Air can be blown into the inner cavity of the dispersion bin through the air blowing opening in the side face of the dispersion bin, carrier gas blown into the dispersion bin from the air blowing opening can be mixed with carrier gas in the inner cavity of the dispersion bin and rotate, powder mixed with the carrier gas is in bulk and good in fluidity, and meanwhile the powder outlet is formed in the tangential direction of the side wall of the dispersion bin. Therefore, the rotated powder can be discharged along the powder outlet when passing through the powder outlet. The fine powder conveying device can continuously convey fine powder with the particle size smaller than 20 micrometers and is not prone to being blocked, and therefore the continuity and uniformity of fine powder conveying are guaranteed.

Description

Technical Field

[0001] The utility model belongs to the fields of powder preparation, thermal spraying, 3D printing, etc., and specifically relates to a powder feeding device for conveying fine-particle powder. Background Art

[0002] In the fields of powder metallurgy, thermal spraying, 3D printing, etc., powder particles need to be transported to the working area. In order to improve the quality and precision of the final product, the required particle size is becoming increasingly refined, from 45-106μm to 15-53μm or even 5-20μm. The mainstream powder feeder in the market is the funnel-type scraper powder feeder, which requires the powder to be transported to have a certain fluidity and is more suitable for loosening large-particle powder. When transporting 5-20μm fine-particle powder, agglomeration, agglomeration, intermittent and even clogging of the powder feeding tube often occurs. Fine-particle powder below 5μm cannot even be transported by traditional powder feeders. As a result, some process links that require the uniform feeding of fine powder cannot be guaranteed, affecting the smooth progress of the next process. For example, during the powder plasma spheroidization treatment, it is impossible to evenly and dispersely feed fine-grained irregular metal powders below 20μm into the plasma torch, resulting in the inability to obtain spherical metal powders in a fine particle size range for 3D printing, which is in huge demand. The scarcity of fine-grained spherical metal powder raw materials is the bottleneck problem restricting the development of metal 3D printing. Therefore, solving the problem of fine powder feeding will also indirectly promote the development of the 3D printing industry. In the field of thermal spraying, fine-grained powder raw materials cannot be evenly dispersed and fed in, which leads to the inability to obtain dense thin coatings of uniform thickness in some cases, and some working conditions that require precise repair cannot be completed.

[0003] It can be seen that providing a powder feeding device capable of conveying fine-particle powder is an issue that urgently needs to be solved in the art. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the utility model is to provide a powder conveying device for conveying fine-particle powder. The utility model can solve the problem that fine powder below 20 μm is easy to agglomerate during conveyance.

[0005] The technical solution adopted by the utility model is as follows:

[0006] A powder feeding device for conveying fine particle powder comprises a powder storage bin, a powder feeding mechanism and a dispersion bin, wherein the powder feeding mechanism is installed at the discharge port of the powder storage bin, the dispersion bin is cylindrical, the top of the dispersion bin is connected to the outlet of the powder feeding mechanism, the side cylindrical wall of the dispersion bin is provided with an air blowing port for blowing air into the inner cavity of the dispersion bin along the tangent direction of the side wall of the dispersion bin and a powder outlet for discharging powder, and the powder feeding mechanism is connected to the top of the dispersion bin.

[0007] Preferably, the center of the top of the dispersion bin is connected to the outlet of the powder feeding mechanism.

[0008] Preferably, the side cylindrical wall of the dispersion bin is symmetrically provided with two blowing ports for blowing air into the inner cavity of the dispersion bin along the tangent direction of the side wall of the dispersion bin, and the two blowing ports are rotationally symmetrical about the axis of the dispersion bin.

[0009] Preferably, the air outlet is arranged in the middle position of the dispersion chamber in the height direction.

[0010] Preferably, the powder outlet is arranged at a middle position between the two air outlets.

[0011] Preferably, the powder outlet is arranged in the middle position in the height direction of the dispersion bin.

[0012] Preferably, the powder feeding mechanism is a screw powder feeding mechanism.

[0013] Preferably, the screw powder feeding mechanism comprises a powder feeding bin, a screw rod and a power mechanism, wherein the screw rod is horizontally installed inside the powder feeding bin, the power mechanism is installed on the powder feeding bin and connected to the screw rod, and the power mechanism is used to drive the screw rod to rotate; a feed port is provided on the top of the powder feeding bin at a position opposite to the screw rod, and the feed port of the powder feeding bin is connected to the discharge port of the powder storage bin;

[0014] An air blowing pipe and a powder delivering pipe connected to the inner cavity of the powder delivering bin are provided at the discharge end of the spiral rod on the powder delivering bin. The air blowing pipe and the powder delivering pipe are located on one side of the feed port of the powder delivering bin. The outlet of the air blowing pipe is directly opposite to the inlet of the powder delivering pipe up and down. The outlet of the powder delivering pipe serves as the outlet of the screw powder delivering mechanism and is connected to the top of the dispersion bin.

[0015] Preferably, the tank body of the powder storage bin is in the shape of a cylindrical tank, a feed inlet is provided at the top of the powder storage bin, and a discharge outlet is provided at the bottom of the powder storage bin.

[0016] Preferably, the discharge port of the powder storage bin is in the shape of a funnel.

[0017] The utility model has the following beneficial effects:

[0018] In the powder feeding device for conveying fine-particle powder of the utility model, by setting a dispersion bin, the powder can be dispersed and not easy to agglomerate. The specific principle is: air can be blown into the inner cavity of the dispersion bin through the blowing port on the side of the dispersion bin. Since the blowing port is set tangentially along the side wall of the dispersion bin and the dispersion bin is cylindrical, the carrier gas blown in from the blowing port will mix with the carrier gas in the inner cavity of the dispersion bin and rotate. The powder mixed with the carrier gas is dispersed and has good fluidity. At the same time, the powder outlet is also set tangentially along the side wall of the dispersion bin. Therefore, the rotated powder can be discharged along the powder outlet when passing through the powder outlet. At the same time, the utility model uses the powder storage bin to store a certain amount of powder, and can continuously transport the powder in the powder storage bin to the dispersion bin through the powder feeding mechanism, and the powder can be dispersed and stably output through the dispersion bin. Through experiments, the utility model can continuously convey fine powder below 20 μm and is not easy to be blocked, thereby ensuring the continuity and uniformity of the fine powder conveying. From the above, it can be seen that the utility model can solve the problem of easy agglomeration of fine powder during conveying. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The utility model is a schematic diagram of the structure of a powder feeding device for conveying fine-particle powder.

[0020] Figure 2 It is a cross-sectional schematic diagram of the height of the tangential air inlet of the dispersion bin of the utility model.

[0021] Figure 3-1 When plasma spheroidizing fine-grained molybdenum powder, the product powder spheroidization effect diagram when the fine powder feeding device of the utility model is used to feed powder; Figure 3-2 When plasma spheroidizing fine-grained molybdenum powder, the product powder spheroidization effect diagram is when a traditional powder feeder is used to feed the powder.

[0022] In the figure: powder storage bin 100, screw powder feeding mechanism 200, dispersion bin 300, powder storage tank 110, feed port 120, spiral powder feeding rod 210, powder feeding bin 220, air blowing pipe 221, powder feeding pipe 222, power mechanism 211, first air blowing port 310, second air blowing port 320, powder outlet 330. DETAILED DESCRIPTION

[0023] The following is a further detailed description of the implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0024] like Figure 1As shown, the powder feeding device for conveying fine-particle powder of the utility model comprises a powder storage bin 100, a screw powder feeding mechanism 200 and a dispersion bin 300. The top of the powder storage tank 110 of the powder storage bin 100 is provided with a feed port 120; the screw powder feeding mechanism 200 is connected to the bottom of the powder storage bin 100, and the screw powder feeding mechanism 200 comprises a powder feeding bin 220 and a screw rod 210 horizontally installed inside the powder feeding bin 220, an air blowing pipe 221 is provided at the top left of the powder feeding bin 220, a powder feeding pipe 222 is provided at the bottom left of the powder feeding bin 220, a power mechanism 211 is embedded on the right side of the screw rod 210, and the power mechanism 211 is embedded on the right side of the screw rod 210. 1 can drive the screw 210 to rotate and transport materials; the dispersion bin 300 is cylindrical, the top of the dispersion bin 300 is connected to the powder feeding pipe 222 of the screw powder feeding mechanism 200, and a pair of tangential air blowing ports are symmetrically opened at the middle height position of the cylindrical wall on the side of the dispersion bin 300, which are respectively marked as the first air blowing port 310 and the second air blowing port 320, and a powder outlet 330 connected to the powder conveying pipe is provided on the side of the dispersion bin 300 at the middle position of the two tangential air inlets.

[0025] The tank body 110 of the powder storage bin 100 is in the shape of a cylindrical tank, the top of the tank body 110 is sealed and connected to the feed port 120, the bottom of the tank body 110 is sealed and connected to the screw powder feeding mechanism, and the bottom powder outlet of the tank body 110 is funnel-shaped. The powder in the tank body 110 falls by gravity onto the screw 210 of the sealed screw powder feeding mechanism 200 or into the powder feeding bin 220.

[0026] The screw powder feeding mechanism 200 includes a powder feeding bin 220, a screw rod 210 and a power mechanism 211. The screw rod 210 is horizontally installed inside the powder feeding bin 220. The power mechanism 211 is installed on the powder feeding bin 220 and connected to the screw rod 210. The power mechanism 211 is used to drive the screw rod 210 to rotate. A feed port is provided at the top of the powder feeding bin 220 at a position opposite to the screw rod 210. The feed port of the powder feeding bin 220 is connected to the discharge port of the powder storage bin 100. An air blowing pipe 221 and a powder feeding pipe 222 connected to the inner cavity of the powder feeding bin 220 are provided at the discharge end of the screw rod 210 on the powder feeding bin 220. The air blowing pipe 221 and the powder feeding pipe 222 are located on one side of the feed port of the powder feeding bin 220. The outlet of the air blowing pipe 221 is directly opposite to the inlet of the powder feeding pipe 222 up and down. The outlet of the powder feeding pipe 222 serves as the outlet of the screw powder feeding mechanism 200 and is connected to the top of the dispersion bin 300. The screw 210 in the screw powder feeding mechanism 200 rotates unidirectionally driven by the power mechanism 211, so that the powder falling from the storage bin is transported from right to left. The powder feeding bin 220 is horizontally cylindrical, and the top air blowing pipe 221 on the left side thereof is vertically aligned with the bottom powder feeding pipe 222.

[0027] like Figure 2As shown, the dispersion bin 300 of the utility model is in the shape of an oblate barrel, the center of the top plane of the dispersion bin 300 is sealed and connected to the powder feeding pipe 222 of the spiral powder feeding mechanism 2, and two tangential air blowing ports (i.e., the first air blowing port 310 and the second air blowing port 320) are located at half the height of the dispersion bin 300, and the centers of the two tangential air blowing ports are about the axis of the dispersion bin 300 ( Figure 2 The first air outlet 310 and the second air outlet 320 are rotationally symmetrical about the central axis of the direction perpendicular to the paper surface shown in the figure, and the blowing directions of the first air outlet 310 and the second air outlet 320 are opposite. In this way, under the action of the two tangentially blown high-pressure gases, a high-speed vortex is formed inside the dispersion bin 300, which can disperse the agglomerated fine particles and keep the fine particle powder in a dispersed state for output. The center of the powder outlet 330 is located at the midpoint of the semicircle of the line connecting the centers of the two tangential air inlets on the height section circle where the two tangential air outlets are located, and the direction of the powder outlet is tangent to the circumferential side wall of the dispersion bin along the vortex direction in the dispersion bin. The utility model can realize quantitative and directional delivery of powder dropped from the storage bin through unidirectional rotation of the screw mechanism, and the high-pressure gas is sent in tangentially to the side of the cylindrical dispersion bin to form a high-speed flow vortex inside the dispersion bin, which disperses the fine particle agglomerates sent therein and keeps the fine particle powder in a dispersed state, thus successfully solving the problems in the field of fine powder below 20μm that are easy to agglomerate, uneven powder delivery, intermittent and even blocked powder delivery pipes and cannot be delivered.

[0028] When the powder feeding device of the utility model feeds powder, the powder dispersion degree can be controlled by the pressure of the tangential gas in the dispersion bin, and the powder feeding amount can be adjusted by the rotation speed of the screw, so that the fine particle powder can be smoothly output loosely, evenly, quantitatively, directionally and continuously.

[0029] In the powder feeding device of the utility model, the powder storage bin and the screw powder feeding mechanism, as well as the screw powder feeding mechanism and the dispersion bin are sealed and connected, and the whole is in a sealed state. The several air pipes and powder feeding pipes can be made of plastic, stainless steel or other materials as appropriate, while ensuring sealing.

[0030] The three gases of the powder feeding device of the present invention (i.e., the carrier gas of the first air port 310, the second air port 320 and the air pipe 221) should be the same gas. Inert gases such as N2 and Ar can be selected for easily oxidized powders or powders with requirements on oxygen content. Cheap compressed air can be selected for powders with relatively stable properties.

[0031] The screw in the screw powder feeding mechanism of the utility model rotates unidirectionally, and can continuously and evenly feed a small amount of powder falling from the powder storage bin to the left side of the powder feeding bin. When the powder is sent to the bottom of the air blowing pipe at the top of the left side of the powder feeding bin, the powder is sent to the dispersion bin driven by the airflow. In the dispersion bin, under the action of two streams of high-pressure gas blown in tangentially, a high-speed vortex is formed inside to disperse the agglomerated fine particles, so that the fine-particle powder remains in a dispersed state. Under the action of the airflow, the powder is discharged from the powder outlet of the dispersion bin. The use of the dispersion bin makes the powder loose, uniform and continuous during output, which can effectively prevent the fine-particle powder from agglomerating, intermittent or even clogging the powder feeding pipe during output. The powder feeding amount can be controlled by the screw speed, especially solving the problem of agglomeration of fine-particle metal powder with a particle size of less than 20μm and difficult to transport.

[0032] In order to verify the powder feeding effect of the fine particle powder feeding device of the utility model, the utility model provides the following embodiments.

[0033] Embodiment 1:

[0034] The powder feeding device of this embodiment and the traditional funnel-type scraper-type powder feeding device were compared in the uniformity of fine-particle powder delivery. The experiment collected the fine-particle molybdenum powder delivered by the two powder feeding devices in 4 random 5-minute fixed time periods and weighed them respectively. The results show that the masses of molybdenum powder delivered by the powder feeding device of the utility model in 4 random 5-minute fixed time periods are 200g, 201g, 197g, 200g and 198g respectively, while the masses of molybdenum powder delivered by the traditional powder feeder in 4 random 5-minute fixed time periods are 100g, 201g, 160g, 280g and 350g respectively. It can be seen that the fine-particle powder feeding device of the utility model adopts a dispersion bin, so that the powder feeding rate is relatively stable and uniform; while the traditional powder feeder does not perform special dispersion treatment on the agglomerated fine-particle molybdenum powder, so the powder feeding rate fluctuates widely and the powder feeding is uneven.

[0035] Embodiment 2:

[0036] The experiment of regulating the effect of the screw speed on the powder delivery amount of the powder delivery device in this embodiment was conducted. The experiment collected the fine-grained molybdenum powder delivered within 5 minutes at different screw speeds, and weighed it to study the effect of the screw speed on the powder delivery amount. The results show that under the experimental conditions, when the screw speeds are 5r / min (revolutions / minute), 10r / min, 15r / min, 20r / min, 25r / min, and 30r / min, respectively, the mass of fine powder collected within 5 minutes is 20g, 25g, 30g, 35g, and 40g, respectively. It can be seen that the mass of fine powder delivered within a fixed time is linearly related to the screw speed, that is, the powder delivery amount can be regulated by the screw speed.

[0037] Embodiment 3:

[0038] When plasma spheroidizing fine-grained molybdenum powder, the fine powder feeding device of the utility model and the traditional powder feeder are used to transport the fine-grained molybdenum powder, and the spheroidization effect of the product powder is compared. For metal molybdenum powder raw materials with an average particle size of 15μm, the plasma spheroidization experiment is carried out using the fine powder feeding device of the utility model and the traditional funnel-type scraper powder feeder. During the experiment, all other working conditions and corresponding process parameters except for the powder feeder device are kept exactly the same. The results show that when the fine-grained powder feeding device of the utility model is used to feed powder, the powder spheroidization rate reaches 99.7%, and the product powder is dispersed, the particle size distribution is narrow, and the sphericity of individual powder particles is good. Figure 3-1 As shown; when using the traditional funnel-type scraper powder feeder to feed powder, the powder spheroidization rate after plasma treatment is less than 50%, and there are large agglomerated particles in the powder, the particle size distribution is wide, and the sphericity of individual powder particles is poor, as shown Figure 3-2 As shown. The main reason is that when the powder feeding device of the utility model is used to feed powder, the fine powder particles fed into the plasma torch are in a dispersed state due to the purging effect of the high-speed rotating vortex gas in the dispersion chamber. The dispersion uniformity of the powder feeding makes the heat absorption of each particle in the plasma torch basically uniform, which is conducive to the spheroidization of the fine powder particles and the particle size distribution is uniform; when the traditional powder feeder is used to feed powder, the 15μm molybdenum powder has a small particle size and the particles are easy to agglomerate, resulting in uneven powder feeding rate. The powder particles entering the plasma torch have different heat absorption conditions. Under the given plasma power, some particles can be spheroidized, while those particles that are concentratedly fed cannot be spheroidized, so the spheroidization rate of the product powder is reduced, and those large agglomerated particles cannot be dispersed without external force, so the product powder particle size range is wider.

[0039] The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A powder feeding device for conveying fine-particle powder, characterized in that: The invention comprises a powder storage bin (100), a powder delivery mechanism and a dispersion bin (300), wherein the powder delivery mechanism is installed at the discharge port of the powder storage bin (100), the dispersion bin (300) is cylindrical, the top of the dispersion bin (300) is connected to the outlet of the powder delivery mechanism, the side cylindrical wall of the dispersion bin (300) is provided with a blowing port for blowing air into the inner cavity of the dispersion bin (300) along the tangent direction of the side wall of the dispersion bin (300) and a powder outlet (330) for discharging powder, and the powder delivery mechanism is connected to the top of the dispersion bin (300).

2. A powder feeding device for conveying fine-particle powder according to claim 1, characterized in that: The center of the top of the dispersion bin (300) is connected to the outlet of the powder feeding mechanism.

3. A powder feeding device for conveying fine-particle powder according to claim 1, characterized in that: Two blowing ports for blowing air into the inner cavity of the dispersion bin (300) are symmetrically arranged on the side cylindrical wall of the dispersion bin (300) along the tangent direction of the side wall of the dispersion bin (300), and the two blowing ports are rotationally symmetrical about the axis of the dispersion bin (300).

4. A powder feeding device for conveying fine-particle powder according to claim 1 or 3, characterized in that: The air blowing port is arranged at the middle position of the dispersion chamber (300) in the height direction.

5. A powder feeding device for conveying fine-particle powder according to claim 3, characterized in that: The powder outlet (330) is arranged at the middle position between the two air blowing ports.

6. A powder feeding device for conveying fine-particle powder according to claim 1 or 5, characterized in that: The powder outlet (330) is arranged at the middle position of the dispersion bin (300) in the height direction.

7. A powder feeding device for conveying fine-particle powder according to claim 1, characterized in that: The powder feeding mechanism adopts a screw powder feeding mechanism (200).

8. A powder feeding device for conveying fine-particle powder according to claim 7, characterized in that: The screw powder feeding mechanism (200) comprises a powder feeding bin (220), a screw rod (210) and a power mechanism (211); the screw rod (210) is horizontally installed inside the powder feeding bin (220); the power mechanism (211) is installed on the powder feeding bin (220) and connected to the screw rod (210); the power mechanism (211) is used to drive the screw rod (210) to rotate; a feed port is provided at the top of the powder feeding bin (220) at a position opposite to the screw rod (210); the feed port of the powder feeding bin (220) is connected to the discharge port of the powder storage bin (100); An air blowing pipe (221) and a powder feeding pipe (222) are provided on the powder feeding bin (220) at the discharge end of the spiral rod (210), and are communicated with the inner cavity of the powder feeding bin (220). The air blowing pipe (221) and the powder feeding pipe (222) are located on one side of the feed port of the powder feeding bin (220). The outlet of the air blowing pipe (221) and the inlet of the powder feeding pipe (222) are vertically opposite to each other. The outlet of the powder feeding pipe (222) serves as the outlet of the screw powder feeding mechanism (200) and is communicated with the top of the dispersion bin (300).

9. A powder feeding device for conveying fine-particle powder according to claim 1, characterized in that: The tank body (110) of the powder storage bin (100) is in the shape of a cylindrical tank, a feed port (120) is provided at the top of the powder storage bin (100), and a discharge port is provided at the bottom of the powder storage bin (100).

10. A powder feeding device for conveying fine-particle powder according to claim 1, characterized in that: The discharge port of the powder storage bin (100) is in the shape of a funnel.

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