Superfine powder filling machine and graphitization furnace comprising same

Abstract

The utility model provides a kind of superfine powder filling machine and including its graphitization furnace, superfine powder filling machine includes: lower hopper is installed in the upper end portion of outer shell body, for conveying downward and forcedly downward powder material;Material collecting cover is installed in the lower end portion of outer shell body, for collecting compressed powder material;Multi-stage pair of rollers are sequentially arranged from top to bottom along the inner wall surface of outer shell body, and each stage pair of rollers includes at least two opposite rotating rollers;Driving device is connected with pair of rollers, for driving pair of rollers to rotate;Pair of rollers and lower hopper form a cavity, vacuum equipment is installed at the cavity, for extracting gas in powder material, and make the negative pressure in working area form.The utility model adopts the way of pair of rollers step-by-step compression under negative pressure state, make gas discharge more easily in superfine powder compression process, to improve compression efficiency.It can greatly improve the filling amount of negative electrode material in crucible, to effectively reduce the power consumption of negative electrode material graphitization process, reduce graphitization production cost.

Description

Technical Field

[0001] This utility model relates to the field of graphitization furnace production, and in particular to an ultrafine powder filling machine and a graphitization furnace including the same. Background Technology

[0002] In recent years, with the implementation of national new energy policies, lithium batteries have been widely used in automobiles, energy storage, and other fields. However, the manufacture of lithium batteries requires a large amount of positive and negative electrode materials. Furthermore, positive and negative electrode materials are the main components of lithium batteries and also constitute the main cost of lithium battery production.

[0003] Currently, the production of lithium-ion battery anode materials requires the transformation of carbonaceous materials into graphite anode materials at temperatures exceeding 2500℃. In the graphitization process of producing anode materials, a carbon-graphite crucible is filled with anode carbon powder in a graphitization furnace, and then subjected to high temperatures to graphitize the carbon powder into graphite powder. Typically, the graphitization process for one ton of anode material requires 8000 kW of electrical energy. Therefore, the graphitization production of anode materials is a high-energy-consuming industrial process.

[0004] In existing graphitization production methods for anode materials, the main equipment used is a graphitization furnace, equipped with a graphitization transformer power supply. The process begins with loading the anode material into a specialized graphite crucible. Then, the graphite crucible containing the anode material is placed into the graphitization furnace. Next, electricity is supplied to the furnace, raising the temperature to over 2500℃, thus transforming the material into a graphitic material.

[0005] In the entire graphitization production of anode materials, the anode material is ultrafine coke powder, with a very fine particle size. The number of crucibles that can be loaded into each graphitization furnace is fixed. The amount of anode material loaded into each crucible, along with the total number of crucibles, determines the furnace's loading capacity. Therefore, the power consumption and production cost of graphitization production in each furnace are essentially constant and have little to do with the quantity of product loaded into the crucibles. The quantity of anode material loaded into the crucibles directly affects the power consumption and production cost.

[0006] For example, in actual production, due to the ultra-fine particle size of the negative electrode material, often below 20 μm, it is difficult to expel air from the powder when filling it into a graphite crucible. This results in a low packing density of the powder inside the crucible, ranging from 0.85 to 0.95 g / cm³. 3 It has a density 2.36 g / cm³ higher than the theoretical density. 3 The difference is significant. When the packing density is 0.9 g / cm³... 3 At that time, the power consumption for graphitization was 8000kw / ton of product, and the production cost for graphitization was 8500 yuan / ton.

[0007] However, the crucibles for containing the negative electrode powder need to withstand temperatures above 2500℃, which necessitates the use of graphite crucibles. Graphite crucibles have very low mechanical strength, and high-power, high-pressure, and high-vibration powder filling machinery can easily damage them, making them unsuitable for negative electrode powder filling production.

[0008] Therefore, to reduce the power consumption and production cost of graphitization, maximizing the amount of negative electrode material packed in the crucible is the most direct way to reduce power consumption and cost. In actual production, the amount of powder packed in each crucible does not affect the total production cost of graphitization in that batch, but the production cost per unit weight of negative electrode powder is calculated by dividing the total cost of graphitization in that batch by the total amount of powder in all crucibles in that batch.

[0009] In view of this, the inventor of this utility model has designed an ultrafine powder filling machine and a graphitization furnace including the same, in order to overcome the above-mentioned technical problems. Utility Model Content

[0010] The technical problem to be solved by this utility model is to overcome the defects of the prior art, such as difficulty in gas discharge and low compression efficiency during the compression of ultrafine powder when filling negative electrode material in graphite crucible, and to provide an ultrafine powder filling machine and a graphitization furnace including the same.

[0011] The present invention solves the above-mentioned technical problems through the following technical solution:

[0012] An ultrafine powder filling machine, characterized in that the ultrafine powder filling machine comprises:

[0013] A hopper and an outer casing, wherein the hopper is installed at the upper end of the outer casing for conveying powder downwards;

[0014] A material collection hood is installed at the lower end of the outer shell and is used to collect compressed powder.

[0015] The multi-stage rollers are arranged sequentially from top to bottom along the inner wall of the outer shell. Each stage of the rollers includes at least two rollers rotating in opposite directions, used to compress the powder downwards and force it downwards.

[0016] A driving device, connected to the rollers, is used to drive the rollers to rotate and compress and convey the powder.

[0017] A vacuum pump is installed in the cavity between the rollers and the hopper to extract gas from the powder and create a negative pressure in the working area.

[0018] According to one embodiment of the present invention, the spacing between the rollers of each level of the roller pair decreases sequentially from top to bottom. In two adjacent levels of roller pairs, the spacing between the rollers of the next level of roller pair is reduced by 2% to 15% compared to the spacing between the rollers of the previous level of roller pair.

[0019] According to one embodiment of the present invention, the ultrafine powder filling machine includes at least five stages of rollers.

[0020] According to one embodiment of the present invention, the particle size of the powder is less than or equal to 50 micrometers.

[0021] According to one embodiment of the present invention, the powder is lithium battery negative electrode powder, ultrafine carbon black, or plant cell wall broken powder.

[0022] According to one embodiment of the present invention, the roller is a cylinder, and the surface of the cylinder has a toothed surface.

[0023] According to one embodiment of the present invention, the surface of the rack is a plane or an arc surface, the rack is arranged on the surface of a cylinder, and the cross-section is star-shaped.

[0024] According to one embodiment of the present invention, a pressure sensing device is installed inside the material collection hood to collect and transmit filling information to the control system, and the filling density of the powder is adjusted by the control system.

[0025] According to one embodiment of the present invention, the rollers of the pair of rollers are respectively installed in the outer casing via rotating shafts, and each row of rollers from top to bottom is connected by a chain. The driving device is connected to the rotating shaft of the uppermost pair of rollers, and the driving device drives the uppermost pair of rollers to rotate, while the chain drives the other pair of rollers to rotate together.

[0026] According to one embodiment of the present invention, the outer shell is further provided with multiple rows of guide posts, the guide posts are located on both sides of the rollers, and the chain is clamped between the guide posts and the rotating shaft of the rollers.

[0027] This utility model also provides a graphitization furnace, characterized in that the graphitization furnace includes at least one ultrafine powder filling machine, a feeding and storage system and multiple powder containers as described above, the ultrafine powder filling machine is installed inside the powder containers, and the feeding and storage system is installed above the ultrafine powder filling machine for conveying powder to the downward hopper.

[0028] The positive and progressive effects of this utility model are as follows:

[0029] This utility model of an ultrafine powder filling machine and a graphitization furnace including the same has the following advantages:

[0030] 1. The use of a roller compression method under negative pressure makes it easier for gas to escape during the compression of ultrafine powder, thereby improving the compression efficiency;

[0031] Second, the ultrafine powder will not cause impact or damage to the container during compression;

[0032] Third, the equipment has a simple structure, is easy to manufacture, maintain, repair, and operate, and is inexpensive;

[0033] Fourth, significantly increase the amount of negative electrode material filled in the crucible, thereby effectively reducing the power consumption of the graphitization process of the negative electrode material and reducing the production cost of graphitization. Attached Figure Description

[0034] The above and other features, properties and advantages of this utility model will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0035] Figure 1 This is a schematic diagram of the structure of the ultrafine powder filling machine of this utility model.

[0036] Figure 2 for Figure 1 A sectional view taken along line AA.

[0037] Figure 3 This is a side view of the ultrafine powder filling machine of this utility model.

[0038] Figure 4 This is a schematic diagram of the chain installation in the ultrafine powder filling machine of this utility model.

[0039] Figure 5 This is a schematic diagram of the internal structure of the ultrafine powder filling machine of this utility model.

[0040] Figure 6 This is a schematic diagram of the operation of the ultrafine powder filling machine of this utility model.

[0041] Figure 7 This is a schematic diagram of the graphitization furnace of this utility model.

[0042] [Attached image labels]

[0043] 10 feeding hoppers

[0044] 20 outer shell

[0045] Material collection hood 30

[0046] 40 rollers

[0047] Drive unit 50

[0048] Vacuum equipment 60

[0049] Powder 70

[0050] Roller 41

[0051] Chain 80

[0052] Rotating shaft 42

[0053] Guide column 90

[0054] Cavity 11

[0055] 100 Ultrafine Powder Filling Machine

[0056] 200 feeding and storage system

[0057] Multiple powder containers 300 Detailed Implementation

[0058] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0059] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the present invention will now be described in detail, examples of which are shown in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts.

[0060] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.

[0061] Furthermore, it is required that this utility model be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0062] like Figure 1 and Figure 2 As shown, this utility model discloses an ultrafine powder filling machine, including: a feeding hopper 10, an outer shell 20, a material collecting hood 30, a multi-stage roller 40, a driving device 50, and a vacuum device 60. The feeding hopper 10 is installed at the upper end of the outer shell 20 and is used to convey powder 70 downwards.

[0063] A collection hood 30 is installed at the lower end of the outer casing 20 to collect the compressed powder 70. The size and shape of the collection hood 30 are determined according to the size and shape of the powder container (e.g., a crucible). The collection hood 30 prevents the powder from being thrown up when the rotating rollers 40 feed the powder 70 into the container.

[0064] In addition, a pressure sensor can be installed on the material collection hood 30. The pressure sensor will collect the filling information and transmit it to the equipment control system (e.g., control computer). The equipment control system will then control the filling machine to move upward and adjust the pressure to control the density of the powder filling. In other words, the powder filling density is adjusted by the control system.

[0065] Preferably, the particle size of powder 70 in this application is set to be less than or equal to 50 micrometers, for example, preferably 10 to 20 micrometers, or preferably 30 micrometers, all of which can meet the requirements of the technical solution of this application. In addition, powder 70 can be lithium battery negative electrode powder, ultrafine carbon black, or plant cell wall broken powder.

[0066] Here, when powder 70 is preferably lithium battery anode powder, the particle size of the lithium battery anode powder can preferably be 3 micrometers to 30 micrometers, and it is fed into the hopper 10 through a feeding device. Of course, powder 70 is also suitable for other micrometer-sized and low-density ultrafine powders, such as ultrafine carbon black and plant cell wall broken powder.

[0067] Multi-stage rollers 40 are arranged sequentially from top to bottom along the inner wall of the outer casing 20. Each stage of rollers 40 includes at least two opposing rotating rollers 41 (for example, two rollers are arranged opposite each other in this embodiment). The opposing rotation of the rollers 41 conveys the loose powder 70 downwards while simultaneously compressing it. For example, in the first stage of rollers 40, the left roller 41 rotates clockwise and the right roller 41 rotates counterclockwise, compressing the powder entering the gap between the two rollers. After the initial compression by the uppermost first-stage rollers 40, the bulk density of the powder 70 is higher than that of the powder in the hopper 10. Each downward-moving stage of rollers 40 further compresses the initially compressed powder 70 and forces it downwards. This multi-stage roller structure achieves a better compression effect. Finally, the multi-stage compressed powder is concentrated below the collecting hood 30 and filled into a container.

[0068] Each roller 41 is preferably cylindrical, with toothed strips on its surface. Specifically, the surface of the toothed strips can be flat or curved, and the strips are arranged on the cylindrical surface with a star-shaped cross-section. Powder 70 is filled when the toothed grooves of the roller 41 face upwards. When it rotates to intersect with the teeth of the opposite roller, the powder is compressed. Upon further rotation, the toothed grooves press the compressed powder downwards. The multi-stage, relatively rotating toothed rollers 41 compress the ultrafine powder 70 flowing downwards, expelling gas from the powder 70 until it reaches a certain density, at which point it is filled into the container below.

[0069] Preferably, the spacing between the rollers 41 of each of the roller pairs 40 decreases sequentially from top to bottom.

[0070] More preferably, in two adjacent stages of rollers 40, the spacing between the rollers 41 of the next stage roller 40 is 2% to 15% smaller than the spacing between the rollers 41 of the previous stage roller 40. For example, in this embodiment, the spacing between the rollers 41 of the next stage roller 40 is 5% smaller than the spacing between the rollers 41 of the previous stage roller 40. For example, in this embodiment, the tooth height of the first stage roller is preferably greater than 20mm, the spacing of the upper stage roller 40 is about 5mm larger than the spacing of the lower stage roller 40, and the spacing of the last stage roller 40 is about 10mm. The bottom of the outer casing 20 is configured as an arc-shaped plate, which matches the last stage roller 40.

[0071] This allows the gap between the rollers 41 of each stage of the roller pair 40 to gradually decrease from top to bottom, until in the last stage of the roller pair 40, the two rollers 41 mesh with each other or are very close. The multi-stage roller pair 40 is arranged from top to bottom, and the gap of the next stage roller pair 40 is gradually smaller than the gap of the previous stage roller pair 40, which can ensure the grading and compression of powder, while forcing it to be conveyed downward.

[0072] Preferably, the gap adjustment of the multi-stage rollers 40 can typically be achieved in one of two ways: First, using rollers of the same size, the gap between each stage of the rollers can be directly adjusted. Second, rollers of different sizes can be designed, and the gap between each stage of the rollers can be changed by adjusting the diameter of each stage of the rollers and adjusting the installation position of the roller rotation shaft during installation.

[0073] Furthermore, the number of stages of the compression rollers 40 can be determined according to the predetermined degree of compression. For crucible filling of the negative electrode material, more than 5 stages are more reasonable. For example, 7 stages of rollers are used in this embodiment. Since the powder 70 contains a large amount of gas (e.g., air), it is difficult to expel the gas in one go. Therefore, this application uses multiple stages of rollers to slowly compress the powder step by step. Each stage of rollers compresses the powder in sequence, compressing it while conveying it downwards, thereby maximizing the discharge of gas from the powder.

[0074] like Figures 3 to 5 As shown, the drive unit 50 is connected to the rollers 40 and is used to drive the rollers 40 to rotate and compress and convey the powder 70. Preferably, the rollers 41 of each stage of the rollers 40 are respectively mounted on the side wall of the outer casing 20 (e.g., a square outer casing) via a rotating shaft 42, and the rollers 41 are installed inside the outer casing 20. In the longitudinal direction, each row of rollers 41 from top to bottom is connected by a chain 80, which connects the drive unit 50 to the rotating shaft 42 of the uppermost roller 40 (i.e., the first stage roller).

[0075] In this embodiment, each stage of the roller pair 40 is equipped with two relatively rotating rollers, and the multi-stage roller pair 40 forms two rows of rollers 41. Each row of rollers 41 is connected vertically by a chain 80. The drive device 40 is also connected to the rotation shaft of the uppermost first-stage roller pair via a chain. When the drive device 50 drives the uppermost roller pair 40 (i.e., the first-stage roller pair) to rotate, the chain 80 drives the remaining multi-stage roller pairs 40 to rotate together. Thus, only one drive device 50 is needed to drive all multi-stage roller pairs 40 to rotate simultaneously.

[0076] In addition, multiple rows of guide posts 90 are provided on the outer casing 20, and the guide posts 90 are arranged on both sides of the roller 40, with the chain 80 sandwiched between the guide posts 90 and the rotating shaft of the roller.

[0077] like Figure 6 As shown, when the multi-stage rollers 40 compress the powder 70 and convey it downwards, the vacuum equipment 60 simultaneously extracts the gas (e.g., air) from the outer casing 20, creating a certain negative pressure in the working area. A cavity 11 is formed between the rollers 40 and the hopper 10. The multi-stage rollers 40 compress the powder 70, discharging the gas (e.g., air) from the powder 70 into the cavity 11.

[0078] For example, in this embodiment, the vacuum pumping device 60 preferably includes a vacuum tube and a vacuum pumping system, with one end of the vacuum tube connected to the cavity 11 and the other end connected to the vacuum pumping system.

[0079] A vacuum device 60 is installed in the cavity 11, which puts the cavity 11 under negative pressure and removes the gas discharged by the multi-stage rollers 40 during extrusion. In actual use, the entire system maintains a negative pressure of about 10,000 Pa. The gas extracted contains a large amount of negative electrode powder, which is separated by the gas-solid separation device and returned to the upper feed hopper 10.

[0080] In practice, the conventional tool for compacting solid materials is a press. A press applies pressure to the powder from top to bottom through a pressure head, which is the most effective and direct method. However, this application addresses ultrafine powders, which are very loose and contain more than 50% air. This means that the press cannot effectively compact the powder during the actual compaction process. Once the press applies pressure to the powder, the air inside needs to escape, requiring a channel. Therefore, the press's die cannot be completely sealed, causing the powder and air to escape together.

[0081] Therefore, this application uses multi-stage rollers to compress the powder in stages, gradually and fully expelling the gas (e.g., air) from the powder into the upper cavity. The compressed powder is then conveyed downwards as the rollers rotate. Simultaneously, a vacuum device is used to create a negative pressure state in the cavity, thereby extracting air from the cavity and achieving separation of air and powder.

[0082] In the operation of the ultrafine powder filling machine described in this application, vacuuming and filling are carried out simultaneously. The powder is conveyed from top to bottom, and each stage of rollers performs a small amount or a certain proportion of compression. The compression amount at each stage is small, so that the air in the powder will escape under the action of external force. At the same time, a vacuuming device is added to help the gas to be discharged to the outside.

[0083] like Figure 7 As shown, this utility model also provides a graphitization furnace, including at least one ultrafine powder filling machine 100 as described above, a feeding and storage system 200, and multiple powder containers 300 (e.g., crucibles, crucible moving platforms), with the ultrafine powder filling machine 100 installed inside the powder container 300. In actual production, the ultrafine powder filling machine 100 extends into the powder container 300, ensuring that the collecting hood 30 contacts the bottom of the powder container 300 as much as possible before starting the filling operation. The feeding and storage system 200 is installed above the ultrafine powder filling machine 100 and is used to convey powder 70 to the downward hopper 10.

[0084] In summary, the ultrafine powder filling machine and the graphitization furnace including it of this utility model have the following advantages:

[0085] First, the use of a roller-driven, staged compression method makes it easier for gas to escape during the compression of ultrafine powder, thereby improving compression efficiency.

[0086] Second, the ultrafine powder will not cause impact or damage to the container during compression.

[0087] Third, the equipment has a simple structure, is easy to manufacture, maintain, and operate, and is inexpensive. The cost of the ultrafine powder filling machine applied for in this application to achieve the same filling output is only half that of existing filling equipment in the industry.

[0088] Fourth, significantly increase the amount of negative electrode material filled in the crucible, thereby effectively reducing the power consumption of the graphitization process of the negative electrode material and reducing the production cost of graphitization.

[0089] V. High production efficiency and significant compression effect; compared with existing methods using vibration, vacuuming, mechanical pressing, and manual tamping, the compaction density is increased by 0.3 g / cm³. 3 above.

[0090] VI. With the same graphitization furnace production, the output can be increased by more than 30% by adjusting the crucible filling density. The power consumption and production cost of the negative electrode powder graphitization process are reduced by 30%. The power consumption of the existing negative electrode material graphitization process has been reduced from 8,000 kWh / ton to below 6,000 kWh / ton, and the production cost has been reduced from 8,500 yuan / ton to below 6,000 yuan / ton.

[0091] For those skilled in the art, the above disclosure of utility models is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0092] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0093] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments of the utility model, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not mean that the subject matter of the present application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiments disclosed above.

[0094] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. An ultrafine powder filling machine, characterized in that, The ultrafine powder filling machine includes: A hopper and an outer casing, wherein the hopper is installed at the upper end of the outer casing for conveying powder downwards; A material collection hood is installed at the lower end of the outer shell and is used to collect compressed powder. The multi-stage rollers are arranged sequentially from top to bottom along the inner wall of the outer shell. Each stage of the rollers includes at least two rollers rotating in opposite directions, used to compress the powder downwards and force it downwards. A driving device, connected to the rollers, is used to drive the rollers to rotate and compress and convey the powder. A vacuum pump is installed in the cavity between the rollers and the hopper to extract gas from the powder and create a negative pressure in the working area.

2. The ultrafine powder filling machine as described in claim 1, characterized in that, The spacing between the rollers of each level of the roller pair decreases sequentially from top to bottom. In adjacent levels of roller pairs, the spacing between the rollers of the next level is reduced by 2% to 15% compared to the spacing between the rollers of the previous level.

3. The ultrafine powder filling machine as described in claim 1, characterized in that, The ultrafine powder filling machine includes at least five stages of rollers.

4. The ultrafine powder filling machine as described in claim 1, characterized in that, The particle size of the powder is less than or equal to 50 micrometers.

5. The ultrafine powder filling machine as described in claim 1, characterized in that, The powder is lithium battery negative electrode powder, ultrafine carbon black, or plant cell wall broken powder.

6. The ultrafine powder filling machine as described in claim 1, characterized in that, The roller is a cylinder with toothed surfaces.

7. The ultrafine powder filling machine as described in claim 6, characterized in that, The surface of the rack is either flat or curved, and the racks are arranged on the surface of a cylinder with a star-shaped cross-section.

8. The ultrafine powder filling machine as described in claim 1, characterized in that, A pressure sensor is installed inside the material collection hood to collect and transmit filling information to the control system, which is used to adjust the filling density of the powder.

9. The ultrafine powder filling machine as described in claim 1, characterized in that, The rollers of the pair of rollers are respectively mounted in the housing through rotating shafts. Each row of rollers from top to bottom is connected by a chain. The drive device is connected to the rotating shaft of the uppermost pair of rollers and drives the uppermost pair of rollers to rotate, and the chain drives the other pairs of rollers to rotate together.

10. The ultrafine powder filling machine as described in claim 9, characterized in that, The outer casing is also provided with multiple rows of guide posts, which are located on both sides of the rollers, and the chain is clamped between the guide posts and the rotating shaft of the rollers.

11. A graphitization furnace, characterized in that, The graphitization furnace includes at least one ultrafine powder filling machine, a feeding and storage system, and a plurality of powder containers as described in any one of claims 1-10. The ultrafine powder filling machine is installed inside the powder containers, and the feeding and storage system is installed above the ultrafine powder filling machine for conveying powder to the downward hopper.

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