Airflow pulverization system

Abstract

This application provides an airflow pulverizing system, relating to the field of dry powder material flow ultrafine pulverization technology. It includes an airflow pulverizer and a dual-channel nozzle. The airflow pulverizer has a pulverizing chamber, and the dual-channel nozzle has a feed channel and an air inlet channel. The nozzle of each of the feed channel and the air inlet channel is connected to the pulverizing chamber. The air inlet channel includes a first section and a second section connected to each other. The inlet of the air inlet channel is formed in the first section, and the second section is spaced apart and disposed on the inner circumference of the feed channel. The nozzle of the air inlet channel is formed at the end of the second section opposite to the first section and adjacent to the nozzle of the feed channel, so that the powder material flow and the compressed airflow can enter the pulverizing chamber coaxially. This application changes the powder material feeding method of the airflow pulverizer, allowing the powder material flow and the compressed airflow to enter the airflow pulverizer coaxially, enabling the material particles to obtain a longer acceleration distance, thereby increasing the speed of particle collision, friction, and shearing, and ensuring the pulverizing effect.

Description

Technical Field

[0001] This application relates to the field of dry powder material flow ultrafine grinding technology, and in particular to an airflow grinding system. Background Technology

[0002] Air jet mills, as important equipment for ultrafine grinding, are widely used in the ultrafine grinding of non-metallic minerals, chemical raw materials, lithium battery materials, etc. The working principle of an air jet mill is generally as follows: compressed air, after being filtered and dried, is injected at high speed into the grinding chamber through a Laval nozzle. At the confluence of multiple high-pressure airflows, the material is repeatedly pulverized through collision, friction, and shearing. The pulverized material, under the suction of the induced draft fan, moves with the rising airflow to the classification zone. Under the strong centrifugal force generated by the high-speed rotating classification wheel, coarse and fine materials are separated. Fine particles that meet the particle size requirements pass through the classification wheel and are collected by the dust collector, while coarse particles descend back to the grinding zone for further pulverization.

[0003] Whether particles can be crushed depends on their impact velocity. During the impact process, particles can only be broken when their elastic energy exceeds their own crushing energy. The amount of elastic energy depends solely on the conversion of kinetic energy during the collision. Therefore, the higher the impact velocity, the easier it is for the particles to break. However, airflow pulverizers in related technologies typically use obliquely arranged chutes for feeding, with the extension line of the feed pipe pointing towards the center of the nozzle's spray cross-section. This makes it difficult for particles to achieve a relatively efficient acceleration process in the pulverizing chamber, resulting in a larger output particle size, a wider particle size range, low equipment operating efficiency, and high overall energy consumption. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] Therefore, embodiments of this application propose an airflow pulverizing system that changes the feeding method of powder materials in an airflow pulverizer. The powder material flow and compressed airflow can be coaxially introduced into the airflow pulverizer, allowing the material particles to obtain a longer acceleration distance, thereby increasing the speed of particle collision, friction, and shearing, ensuring pulverizing effect, reducing product particle size, and narrowing the particle size distribution of the product particles.

[0006] An airflow pulverizing system according to an embodiment of this application includes an airflow pulverizer and a dual-channel nozzle. The airflow pulverizer has a pulverizing chamber, and the dual-channel nozzle has a feed channel and an air inlet channel. The feed channel is adapted to allow a flow of powder material to pass through, and the air inlet channel is adapted to allow a compressed airflow to pass through. Both the feed channel and the air inlet channel have an inlet and an outlet. The outlet of each of the feed channel and the air inlet channel is connected to the pulverizing chamber. The air inlet channel includes a first section and a second section that are connected to each other. The inlet of the air inlet channel is formed in the first section, and the second section of the air inlet channel is spaced apart and disposed on the inner circumference of the feed channel. The outlet of the air inlet channel is formed at the end of the second section opposite to the first section and adjacent to the outlet of the feed channel, so that the powder material flow and the compressed airflow can enter the pulverizing chamber coaxially.

[0007] According to the airflow pulverizing system of this application embodiment, by setting the second section of the air inlet channel of the dual-channel nozzle at intervals on the inner circumference of the feed channel, an annular channel can be formed between the outer circumferential wall of the second section of the air inlet channel and the inner circumferential wall of the feed channel. After the powder material enters the feed channel, it can be sprayed into the pulverizing chamber through the annular channel. The compressed airflow is sprayed into the pulverizing chamber from the second section of the air inlet channel in the middle of the annular channel, so as to realize the coaxial passage of the powder material flow and the compressed airflow. After the two converge at the nozzle, since the two flow directions are consistent and the powder material flow still has a certain flow velocity when it enters the pulverizing chamber, the kinetic energy loss between the two is small when the compressed airflow accelerates the powder material flow flowing in the same direction. This is beneficial for the material particles to obtain a longer acceleration distance. Therefore, compared with the related technology, this application changes the feeding method of the powder material in the airflow pulverizer. The powder material flow and the compressed airflow can enter the airflow pulverizer coaxially, so that the material particles can obtain a longer acceleration distance, thereby increasing the speed of particle collision, friction and shearing, ensuring the pulverizing effect, reducing the product particle size, and narrowing the particle size distribution of the product particles.

[0008] In some embodiments, the airflow pulverizing system further includes a raw material silo, a feed pipe, and a conveying fan. The raw material silo is used to store the material to be pulverized and is provided with a first discharge port. The first discharge port is connected to a first end of the feed pipe so that the material to be pulverized can enter the feed pipe. The second end of the feed pipe is connected to the conveying fan, which is adapted to convey the material to be pulverized from the feed pipe to form a powder material flow. The third end of the feed pipe is connected to the inlet of the feed channel.

[0009] Understandably, the raw material silo, as a storage device for the material to be crushed, can ensure the continuous operation of the airflow crushing system when the powder material source is intermittently supplied, while the conveying fan, as the power source for the material to be crushed, provides power for the movement of the material in the feed pipe to form a pneumatic conveying environment and achieve the first acceleration of the material.

[0010] In some embodiments, the raw material silo is further provided with a vibration mechanism, which is used to vibrate the raw material silo to prevent the material to be crushed from bridging in the raw material silo, thereby affecting the smooth discharge of the material to be crushed from the first discharge port.

[0011] In some embodiments, the raw material silo is further provided with a first weighing unit, which is adapted to weigh the remaining material in the raw material silo in order to measure the material conveying volume and further improve the coordination performance of the raw material silo in the operation of the air jet milling system.

[0012] In some embodiments, the raw material silo is further provided with a first feed port, and a first feed valve and a second feed valve are connected in series at the first feed port so that the opening and closing of the first feed port can be jointly controlled by the first feed valve and the second feed valve. The first feed valve is adapted to communicate with a powder material source, and the first feed valve and the second feed valve can be controlled to open and close sequentially when the raw material silo is fed.

[0013] Understandably, the first and second feed valves installed at the first feed inlet can simultaneously achieve the connection and disconnection between the raw material silo and the powder material source, and ensure the airtightness of the powder material source feeding into the raw material silo by opening and closing the first and second feed valves in sequence, effectively avoiding the influence of the external environment on the material to be crushed.

[0014] In some embodiments, the second feed valve is connected to the first feed port via a first hose.

[0015] In some embodiments, the airflow pulverizing system further includes a screw conveyor and a transmitter. The first discharge port, the screw conveyor, the transmitter, and the first end of the feed pipe are connected in sequence. The first discharge port is provided with a first discharge valve to control the opening and closing of the first discharge port. The screw conveyor is used to control the output amount of the material to be pulverized, and the transmitter is used to ensure that the material to be pulverized is conveyed evenly.

[0016] Understandably, when feeding the air jet mill, the frequency of the screw conveyor can be set according to the required feeding speed, and the screw conveyor can be coordinated with the first weighing unit of the raw material silo to accurately control the output of the material to be crushed, while the transmitter can uniformly and stably convey the material to be crushed under the air conveying environment of the conveying fan.

[0017] In some embodiments, the first discharge port is connected to the screw conveyor via a second flexible hose, which cooperates with the first flexible hose to ensure the accuracy of the test results of the first weighing unit.

[0018] In some embodiments, the dual-channel nozzle is further provided with a distributor, which is coaxially installed in the feed channel and communicates with the feed channel to reduce the turbulence of the powder material flow in the feed channel. The distributor and the second section of the air inlet channel are arranged sequentially from the inlet of the feed channel toward the nozzle.

[0019] The cross-sectional area of ​​the distributor gradually decreases from the inlet of the feed channel toward the nozzle to accelerate the flow of powder material.

[0020] It is understandable that after the material to be crushed enters the dual-channel nozzle through the feed pipe, it needs to pass through the distributor in the feed channel and enter the crushing chamber through the nozzle of the feed channel. During this process, because the cross-sectional area of ​​the distributor decreases along the flow direction of the powder material, the cross-section of the feed channel is also reduced. The powder material is first compressed and then expanded when it flows through this cross-section, which can achieve a second acceleration of the material.

[0021] In some embodiments, the nozzle of the air intake channel is connected to the pulverizing chamber via a Laval nozzle, the Laval nozzle being spaced apart on the inner circumferential side of the feed channel; or, the nozzle of the air intake channel has a Laval nozzle structure, so that the compressed airflow is injected into the pulverizing chamber at supersonic speed.

[0022] It is understandable that after the material to be crushed is ejected from the nozzle of the feed channel, the compressed airflow ejected from the nozzle of the air intake channel is accelerated to supersonic speed. Therefore, the material is propelled by the high-speed jet of gas at the nozzle and shot toward the center of the crushing chamber, so as to achieve a third acceleration of the material.

[0023] In some embodiments, the dual-channel nozzles are multiple and arranged at intervals along the circumference of the grinding chamber, so as to improve the uniformity of the distribution of the material to be ground in the grinding chamber when the material to be ground is introduced into the air jet mill, and at the same time increase the collision probability of the material particles in the grinding chamber, thereby further improving the grinding efficiency of the air jet mill. In conjunction with the above structure, it can achieve ultra-fine grinding of material particles, reduce product particle size, and narrow the particle size distribution of product particles.

[0024] In some embodiments, the inlets of the air intake channels of all the dual-channel nozzles are connected through an air-filled ring tube, which is sleeved on the outer periphery of the air jet mill so that compressed air is distributed to the air intake channels of each dual-channel nozzle by the air-filled ring tube, thereby simplifying the overall structure of the air jet milling system.

[0025] In some embodiments, the inlet of the air intake channel is connected to a compressed air source via a heater, so that the compressed air flow is heated by the heater, thereby increasing the gas temperature and storing energy in the form of internal energy. This allows the gas to provide more kinetic energy to the material when it merges with the material, and the heated gas has a better expansion effect in the low-pressure area, resulting in a smaller gas consumption under the same gas velocity conditions.

[0026] In some embodiments, the airflow pulverizing system further includes a classifying wheel, a receiving hopper, and a dust collector connected in sequence. The classifying wheel is connected to the pulverizing chamber and is used to screen powder materials of different particle sizes. The receiving hopper is used to temporarily store powder materials with qualified particle sizes and is provided with a second discharge port. The second discharge port is equipped with a second discharge valve and is adapted to be connected to a discharge tank. The second discharge valve is used to control the opening and closing of the second discharge port. The dust collector is used to separate powder materials with qualified particle sizes from gas.

[0027] In some embodiments, the receiving hopper is further provided with a second weighing unit, which is used to weigh the receiving hopper so that when the weight of the receiving hopper reaches a set value, the powder material is discharged from the second discharge port.

[0028] In some embodiments, the airflow pulverizing system further includes an induced draft fan connected to the dust collector, which enables the pulverizing chamber to form a slight negative pressure so that powder materials of the correct particle size can pass through the classifying wheel.

[0029] Understandably, the induced draft fan can maintain a slightly negative pressure environment in the crushing chamber, providing power for the powder material to pass through the classifying wheel. At the same time, in conjunction with the conveying fan, a stable airflow can be formed in the feed pipe, thus creating a pneumatic conveying environment.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of an airflow pulverizing system according to an embodiment of this application.

[0032] Figure 2 This is a schematic diagram of a dual-channel nozzle in an airflow pulverizing system according to an embodiment of this application.

[0033] Figure 3 This is another structural schematic diagram of a dual-channel nozzle in an airflow pulverizing system according to an embodiment of this application.

[0034] Reference numerals: 1. Airflow pulverizer; 11. Classifier wheel; 2. Dual-channel nozzle; 21. Feed channel; 22. Air inlet channel; 221. First section; 222. Second section; 223. Laval nozzle; 23. Distributor; 24. Air envelope ring pipe; 25. Heater; 3. Raw material bin; 31. First discharge port; 32. Vibrating mechanism; 33. First weighing unit; 34. First feed port; 35. First feed valve; 36. Second feed valve; 37. First hose; 38. First discharge valve; 39. Second hose; 4. Feed pipe; 5. Conveying fan; 6. Screw conveyor; 7. Generator; 8. Receiving bin; 81. Dust collector; 82. Second discharge port; 83. Second discharge valve; 84. Discharge tank; 85. Second weighing unit; 9. Exhaust fan. Detailed Implementation

[0035] The embodiments of this application are described in detail below, with examples of these embodiments illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0036] like Figures 1 to 3 As shown in the figure, an airflow pulverizing system according to an embodiment of this application includes an airflow pulverizer 1 and a dual-channel nozzle 2. The airflow pulverizer 1 has a pulverizing chamber, and the dual-channel nozzle 2 has a feed channel 21 and an air inlet channel 22. The feed channel 21 is adapted to allow a flow of powder material to pass through, and the air inlet channel 22 is adapted to allow a compressed airflow to pass through. Both the feed channel 21 and the air inlet channel 22 have an inlet and an outlet. The outlet of each of the feed channel 21 and the air inlet channel 22 is connected to the pulverizing chamber. The air inlet channel 22 includes a first section 221 and a second section 222 that are connected to each other. The inlet of the air inlet channel 22 is formed in the first section 221, and the second section 222 of the air inlet channel 22 is spaced apart on the inner circumferential side of the feed channel 21. The outlet of the air inlet channel 22 is formed at the end of the second section 222 that is away from the first section 221 and adjacent to the outlet of the feed channel 21, so that the flow of powder material and the compressed airflow can enter the pulverizing chamber coaxially.

[0037] It is understood that, according to the airflow pulverizing system of this application embodiment, by spaced the second section 222 of the air inlet channel 22 of the dual-channel nozzle 2 on the inner circumferential side of the feed channel 21, an annular channel can be formed between the outer circumferential wall of the second section 222 of the air inlet channel 22 and the inner circumferential wall of the feed channel 21, so that the powder material can be sprayed into the pulverizing chamber through the annular channel after entering the feed channel 21, while the compressed airflow is sprayed into the pulverizing chamber from the second section 222 of the air inlet channel 22 in the middle of the annular channel, so as to realize the coaxial passage of the powder material flow and the compressed airflow. After the two converge at the nozzle, due to the flow direction of the two, Since the powder material flow is in the same direction and still has a certain flow velocity when it enters the grinding chamber, the kinetic energy loss between the two is small when the compressed airflow accelerates the powder material flow in the same direction. This is beneficial for the material particles to obtain a longer acceleration distance. Therefore, compared with related technologies, this application changes the feeding method of the powder material in the airflow pulverizer 1. The powder material flow and the compressed airflow can be coaxially introduced into the airflow pulverizer 1, so that the material particles can obtain a longer acceleration distance, thereby increasing the speed of particle collision, friction and shearing, ensuring the pulverization effect, reducing the product particle size, and narrowing the particle size distribution of the product particles.

[0038] Specifically, the grinding chamber can extend along the height direction. The dual-channel nozzle 2 can be installed on the peripheral wall of the airflow mill 1. The dual-channel nozzle 2 may include a material pipe and an airflow pipe, the material pipe being a straight pipe open at both ends (e.g., ...). Figure 2 As shown in the figure, the inner cavity of the material pipe is the feed channel 21, and the peripheral wall of the material pipe has an inlet for the feed channel 21 that communicates with its inner cavity. In this case, the airflow pipe may include a first pipe and a second pipe that are detachably connected (the first pipe and the second pipe can be detachably connected, for example, by means of flange and bolt connection). The inner cavity of the first pipe is the first section 221 of the air intake channel 22, and the inner cavity of the second pipe is the second section 222 of the air intake channel 22. The second pipe can be inserted into the inner cavity of the material pipe, and the outer peripheral wall of the second pipe and the inner peripheral wall of the material pipe define an annular channel. Taking the figure as an example, the first pipe is located to the left of the second pipe, and the right end of the second pipe is the nozzle and is flush with the right end of the material pipe (that is, the nozzle of the feed channel 21); or, the material pipe may include a first straight pipe section and a second straight pipe section that are detachably connected (e.g., Figure 3 As shown in the figure, the inner cavities of the first and second straight pipe sections together define the feed channel 21. In this case, the airflow pipe can be a bend, and the inner cavity of the bend serves as the air inlet channel 22. At least a portion of the bend can be inserted into the inner cavity of the second straight pipe section, and its outer peripheral wall and the inner peripheral wall of the second straight pipe section define an annular channel. For example, in the figure, the first straight pipe section is located to the left of the second straight pipe section, and the right end of the second straight pipe section is the nozzle of the feed channel 21. The right end of the bend is also the nozzle. Ceramic patches can also be installed on the inner peripheral wall of the feed channel 21 to effectively prevent wear on the feed channel 21 and extend the service life of the dual-channel nozzle 2.

[0039] Preferably, the second section 222 of the air inlet channel 22 is coaxially located in the feed channel 21 to ensure that the powder material can be sprayed out evenly after passing through the annular channel.

[0040] like Figure 1 As shown, in some embodiments, the airflow pulverizing system further includes a raw material silo 3, a feed pipe 4, and a conveying fan 5. The raw material silo 3 is used to store the material to be pulverized and is provided with a first discharge port 31. The first discharge port 31 is connected to the first end of the feed pipe 4 so that the material to be pulverized can enter the feed pipe 4. The second end of the feed pipe 4 is connected to the conveying fan 5. The conveying fan 5 is adapted to convey the material to be pulverized in the feed pipe 4 to form a powder material flow. The third end of the feed pipe 4 is connected to the inlet of the feed channel 21.

[0041] Understandably, the raw material silo 3, as a storage device for the material to be crushed, can ensure the continuous operation of the airflow crushing system when the powder material source is intermittently supplied, while the conveying fan 5, as the power source for the material to be crushed, provides power for the movement of the material to be crushed in the feed pipe 4 to form a pneumatic conveying environment and achieve the first acceleration of the material.

[0042] Specifically, the first discharge port 31 can be located at the bottom of the raw material silo 3. The conveying fan 5 can make the gas flow velocity in the feed pipe 4 within the range of 15 to 18 m / s. The gas flow velocity can be, for example, 15 m / s, 15.5 m / s, 16 m / s, 16.5 m / s, 17 m / s, 17.5 m / s, 18 m / s, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] like Figure 1 As shown, in some embodiments, the raw material silo 3 is also provided with a vibration mechanism 32, which is used to vibrate the raw material silo 3 to prevent the material to be crushed from bridging in the raw material silo 3, thereby affecting the smooth discharge of the material to be crushed from the first discharge port 31.

[0044] It should be noted that bridging refers to the phenomenon where, when the material to be crushed is discharged through the first discharge port 31, an arch-shaped structure is formed between the materials, blocking the first discharge port 31.

[0045] like Figure 1 As shown, in some embodiments, the raw material silo 3 is further provided with a first weighing unit 33, which is adapted to weigh the remaining material in the raw material silo 3 in order to measure the material conveying amount and further improve the cooperation performance of the raw material silo 3 in the operation of the airflow pulverizing system.

[0046] like Figure 1As shown, in some embodiments, the raw material silo 3 is further provided with a first feed port 34. The first feed port 34 is connected in series with a first feed valve 35 and a second feed valve 36 so that the first feed valve 35 and the second feed valve 36 jointly control the opening and closing of the first feed port 34. The first feed valve 35 is suitable for communicating with the powder material source. When the raw material silo 3 is feeding, the first feed valve 35 and the second feed valve 36 can be controlled to open and close in sequence.

[0047] It is understandable that the first feed valve 35 and the second feed valve 36 installed at the first feed inlet 34 can, while realizing the connection and disconnection between the raw material silo 3 and the powder material source, ensure the airtightness of the powder material source feeding into the raw material silo 3 by means of the sequential opening and closing of the first feed valve 35 and the second feed valve 36, and effectively avoid the influence of the external environment on the material to be crushed.

[0048] Specifically, the first feed inlet 34 can be located at the top of the raw material silo 3. The second feed valve 36 and the first feed valve 35 can be sequentially installed from bottom to top on the first feed inlet 34. The first feed valve 35 and the second feed valve 36 can also be replaced with a double butterfly valve structure.

[0049] It should be noted that when feeding the raw material silo 3 with the powder material source, the first feed valve 35 can be opened first, and the second feed valve 36 can be closed at this time. After the gas in the pipeline between the first feed valve 35 and the powder material source is discharged, the second feed valve 36 can be opened again, so that the powder material source is connected to the first feed port 34, and the raw material silo 3 can be fed in a closed environment.

[0050] Furthermore, the second feed valve 36 is connected to the first feed port 34 through the first flexible hose 37, that is, the second feed valve 36 and the first feed port 34 are softly connected.

[0051] like Figure 1 As shown, in some embodiments, the airflow pulverizing system further includes a screw conveyor 6 and a transmitter 7. The first discharge port 31, the screw conveyor 6, the transmitter 7, and the first end of the feed pipe 4 are sequentially connected. The first discharge port 31 is provided with a first discharge valve 38 to control the opening and closing of the first discharge port 31. The screw conveyor 6 is used to control the output amount of the material to be pulverized, and the transmitter 7 is used to ensure that the material to be pulverized is conveyed evenly. The screw conveyor 6 can extend along the height direction.

[0052] It is understandable that when feeding the airflow pulverizer 1, the frequency of the screw conveyor 6 can be set according to the required feeding speed, and the screw conveyor 6 can be coordinated with the first weighing unit 33 of the raw material bin 3 to accurately control the output of the material to be pulverized, while the transmitter 7 can uniformly and stably convey the material to be pulverized in the air conveying environment of the conveying fan 5.

[0053] It should be noted that the working principle of transmitter 7 is similar to the negative pressure dilute phase conveying of materials. It is necessary to control the air volume and feed rate to ensure that the material to be crushed enters the feed pipe 4 in a dilute phase.

[0054] Furthermore, the first discharge port 31 is connected to the screw conveyor 6 via a second flexible hose 39. The second flexible hose 39 cooperates with the first flexible hose 37 to ensure the accuracy of the test results of the first weighing unit 33. Similarly, there is a flexible connection between the first discharge port 31 and the screw conveyor 6.

[0055] like Figure 3 As shown, in some embodiments, the dual-channel nozzle 2 is further provided with a distributor 23, which is coaxially installed in the feed channel 21 and communicates with the feed channel 21 to reduce the turbulence of the powder material flow in the feed channel 21. The distributor 23 and the second section 222 of the air intake channel 22 are arranged sequentially from the inlet of the feed channel 21 toward the nozzle.

[0056] The cross-sectional area of ​​the distributor 23 gradually decreases from the inlet of the feed channel 21 toward the nozzle, that is, the cross-sectional area of ​​the distributor 23 gradually decreases from left to right in the figure, so as to accelerate the flow of powder material.

[0057] It is understandable that after the material to be crushed enters the dual-channel nozzle 2 through the feed pipe 4, it needs to pass through the distributor 23 in the feed channel 21 and enter the crushing chamber from the nozzle of the feed channel 21. During this process, because the cross-sectional area of ​​the distributor 23 is reduced along the flow direction of the powder material, the cross-section of the feed channel 21 is also reduced. The powder material is first compressed and then expanded when it flows through this cross-section, which can achieve a second acceleration of the material.

[0058] Specifically, when the dual-channel nozzle 2 includes a material pipe and an airflow pipe, and the material pipe includes a detachably connected first straight pipe section and a second straight pipe section, the mounting end of the distributor 23 can be clamped between the flanges of the first straight pipe section and the second straight pipe section. The flanges of the first straight pipe section and the second straight pipe section can be fixedly connected by bolts. A sealing gasket can also be provided on the outer periphery of the mounting end of the distributor 23, and the sealing gasket is also clamped between the flanges of the first straight pipe section and the second straight pipe section to ensure the sealing of the connection. Taking the figure as an example, the main body of the distributor 23 is located in the inner cavity of the second straight pipe section.

[0059] It should be noted that excessive disturbance of the feed near the outlet side of the dual-channel nozzle 2 (i.e., the nozzle side of the feed channel 21) will change the flow pattern, leading to turbulence at the outlet and thus reducing the grinding efficiency. Therefore, a distributor 23 can be used to reduce the turbulence in the feed channel 21 to achieve a swirling distribution effect and ensure the grinding effect of the material in the grinding chamber. In addition, the distributor 23 has a smaller flow cross-section and a higher air velocity at the cross-section, which will have a certain acceleration effect on the flow of powder material.

[0060] like Figure 2 and Figure 3 As shown, in some embodiments, the nozzle of the air intake channel 22 is connected to the crushing chamber through a Laval nozzle 223, which is spaced apart on the inner circumferential side of the feed channel 21. Alternatively, the nozzle of the air intake channel 22 is in the form of a Laval nozzle structure, so that the compressed airflow is injected into the crushing chamber at supersonic speed.

[0061] It is understandable that after the material to be crushed is ejected from the nozzle of the feed channel 21, the compressed airflow ejected from the nozzle of the air intake channel 22 is accelerated to supersonic speed. Therefore, the material is propelled by the high-speed jet gas at the nozzle and shot toward the center of the crushing chamber to achieve a third acceleration of the material.

[0062] Specifically, the nozzle of the air intake channel 22 can be coaxially inserted into the Laval nozzle 223, and a sealing gasket can be sandwiched between the inner peripheral wall of the nozzle of the air intake channel 22 and the outer peripheral wall of the Laval nozzle 223 to ensure the sealing of the connection. The end of the Laval nozzle 223 opposite to the nozzle of the air intake channel 22 can be flush with the nozzle of the feed channel 21.

[0063] like Figure 1 As shown, in some embodiments, there are multiple dual-channel nozzles 2 arranged at intervals along the circumference of the grinding chamber, so as to improve the uniformity of the distribution of the material to be ground in the grinding chamber when the material to be ground is introduced into the air jet mill 1, and at the same time increase the collision probability of the material particles in the grinding chamber, thereby further improving the grinding efficiency of the air jet mill 1. In conjunction with the above structure, it can achieve ultra-fine grinding of material particles, reduce product particle size, and narrow the particle size distribution of product particles.

[0064] Preferably, multiple dual-channel nozzles 2 are arranged at equal intervals along the circumference of the grinding chamber.

[0065] like Figure 1 As shown, in some embodiments, the inlets of the air intake channels 22 of all dual-channel nozzles 2 are connected through an air envelope ring pipe 24, which is sleeved on the outer periphery of the airflow pulverizer 1, so that compressed air is distributed to the air intake channels 22 of each dual-channel nozzle 2 by the air envelope ring pipe 24, thereby simplifying the overall structure of the airflow pulverizer system.

[0066] like Figure 1 As shown, in some embodiments, the inlet of the air intake channel 22 is connected to the compressed air source through the heater 25, so that the compressed air flow is heated by the heater 25, thereby increasing the temperature of the gas and storing energy in the form of internal energy, so as to provide more kinetic energy to the material when it merges with the material. Moreover, the heated gas has a better expansion effect in the low-pressure area, and the gas consumption is smaller under the same gas velocity conditions.

[0067] Specifically, the inlet of heater 25 can be connected to a compressed air source, the outlet of heater 25 can be connected to an intake manifold, and the end of the intake manifold away from heater 25 can be connected to an air envelope ring pipe 24 so that the air envelope ring pipe 24 can distribute the heated compressed air to the intake passage 22 of each dual-channel nozzle 2.

[0068] like Figure 1 As shown, in some embodiments, the airflow pulverizing system further includes a classifying wheel 11, a receiving hopper 8, and a dust collector 81 connected in sequence. The classifying wheel 11 is connected to the pulverizing chamber and is used to screen powder materials of different particle sizes, so that small particles of qualified particle size can pass through the classifying wheel 11 under the drive of gas, while particles of unqualified particle size return to the pulverizing chamber for re-pulverization. The receiving hopper 8 is used to temporarily store powder materials of qualified particle size and is provided with a second discharge port 82. The second discharge port 82 is equipped with a second discharge valve 83 and is adapted to communicate with a discharge tank 84. The second discharge valve 83 is used to control the opening and closing of the second discharge port 82. The dust collector 81 is used to separate powder materials of qualified particle size from gas.

[0069] Specifically, the classifying wheel 11 can be installed on top of the air jet mill 1. The receiving hopper 8 can be located beside the air jet mill 1 and a dust collector 81 can be installed on its top.

[0070] like Figure 1 As shown, in some embodiments, the receiving hopper 8 is further provided with a second weighing unit 85, which is used to weigh the receiving hopper 8 so that when the weight of the receiving hopper 8 reaches a set value, the powder material is discharged from the second discharge port 82 to ensure the production continuity of the airflow pulverizing system.

[0071] like Figure 1 As shown, in some embodiments, the airflow pulverizing system further includes an induced draft fan 9, which is connected to a dust collector 81. The induced draft fan 9 can create a slight negative pressure in the pulverizing chamber so that powder materials with the correct particle size can pass through the classifier wheel 11. The outlet of the induced draft fan 9 can be connected to an external exhaust gas treatment device to treat the exhaust gas.

[0072] Understandably, the induced draft fan 9 can maintain a slightly negative pressure environment in the crushing chamber, providing power for the powder material to pass through the classifier wheel 11. At the same time, in conjunction with the conveying fan 5, a stable airflow can be formed in the feed pipe 4, thereby creating a pneumatic conveying environment.

[0073] It should be noted that the specific structures and working principles of the rapping mechanism 32, the first weighing unit 33, the screw conveyor 6, the transmitter 7, the distributor 23, the heater 25, the classifying wheel 11, the dust removal chamber, and the induced draft fan 9 can adopt existing technologies in this field, and will not be elaborated here. Furthermore, the entire process can be intelligently monitored by an intelligent monitoring and control system, automatically adjusting some parameters in the process, such as motor speed and inlet pressure, and collecting data returned by equipment sensors in real time, automatically adjusting according to the parameters set in the human-machine interface system.

[0074] Therefore, the advantage of this application over related technologies lies in changing the feeding method of powder materials in the air jet mill 1, enabling feeding along the axial direction of the dual-channel nozzle 2, achieving three-stage acceleration of powder materials, and having good material crushing ability. The radial distribution of materials in the crushing chamber is better, reducing product particle size, narrowing the particle size distribution of products, and improving the crushing efficiency of the air jet mill 1.

[0075] The working process of this air jet milling system will now be explained in detail, based on its specific structure:

[0076] S1. Close the first discharge valve 38 of the raw material silo 3, and open and close the first feed valve 35 and the second feed valve 36 in sequence so that the material to be crushed is conveyed to the raw material silo 3, and then close the first feed valve 35 and the second feed valve 36.

[0077] S2. Turn on the conveying fan 5 and the induced draft fan 9 to create a pneumatic conveying environment in the feed pipe 4;

[0078] S3. Start the stage wheel 11 and open the main intake valve of the compressed air source;

[0079] S4. Open the screw conveyor 6 and the first discharge valve 38, adjust the screw conveyor 6 to a suitable frequency according to the first weighing unit 33 of the raw material bin 3, and convey the powder material to the air jet mill 1 through the transmitter 7. Under the action of the dual-channel nozzle 2, the material particles are crushed.

[0080] S5. Small particles with qualified particle size are screened by the classifying wheel 11 and pass through the classifying wheel 11 to the receiving hopper 8. The dust collector 81 performs gas-solid separation and finally conveys them to the discharge tank 84. Particles with unqualified particle size are returned to the crushing chamber for re-crushing.

[0081] In addition, the vibration mechanism 32 can be activated in a timely manner according to the actual situation during the above operation to prevent materials from bridging in the raw material silo 3.

[0082] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0083] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0084] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0085] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0086] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0087] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An air jet milling system characterized in that, The device includes an airflow pulverizer (1) and a dual-channel nozzle (2). The airflow pulverizer (1) has a pulverizing chamber, and the dual-channel nozzle (2) has a feed channel (21) and an air inlet channel (22). The feed channel (21) is adapted to allow a flow of powder material to pass through, and the air inlet channel (22) is adapted to allow a compressed airflow to pass through. Both the feed channel (21) and the air inlet channel (22) have an inlet and an outlet. The outlet of each of the feed channel (21) and the air inlet channel (22) is connected to the pulverizing chamber. The air intake channel (22) includes a first section (221) and a second section (222) that are connected to each other. The inlet of the air intake channel (22) is formed in the first section (221). The second section (222) of the air intake channel (22) is spaced apart on the inner circumference of the feed channel (21). The nozzle of the air intake channel (22) is formed at the end of the second section (222) away from the first section (221) and adjacent to the nozzle of the feed channel (21), so that the powder material flow and the compressed air flow can enter the crushing chamber coaxially.

2. The airflow pulverizing system according to claim 1, characterized in that, It also includes a raw material silo (3), a feed pipe (4) and a conveying fan (5). The raw material silo (3) is used to store the material to be crushed and is provided with a first discharge port (31). The first discharge port (31) is connected to the first end of the feed pipe (4) so ​​that the material to be crushed can enter the feed pipe (4). The second end of the feed pipe (4) is connected to the conveying fan (5). The conveying fan (5) is adapted to convey the material to be crushed in the feed pipe (4) to form a powder material flow. The third end of the feed pipe (4) is connected to the inlet of the feed channel (21). And / or, the raw material silo (3) is also provided with a vibrating mechanism (32), which is used to vibrate the raw material silo (3) to prevent the material to be crushed from bridging in the raw material silo (3); And / or, the raw material silo (3) is further provided with a first weighing unit (33), which is adapted to weigh the remaining material in the raw material silo (3) in order to measure the amount of material conveyed.

3. The airflow pulverizing system according to claim 2, characterized in that, The raw material silo (3) is also provided with a first feed port (34). The first feed port (34) is connected in series with a first feed valve (35) and a second feed valve (36) so that the first feed valve (35) and the second feed valve (36) jointly control the opening and closing of the first feed port (34). The first feed valve (35) is suitable for communicating with the powder material source. When the raw material silo (3) is fed, it can control the first feed valve (35) and the second feed valve (36) to open and close in sequence. And / or, the second feed valve (36) is connected to the first feed port (34) via the first hose (37).

4. The airflow pulverizing system according to claim 2, characterized in that, It also includes a screw conveyor (6) and a transmitter (7). The first discharge port (31), the screw conveyor (6), the transmitter (7) and the first end of the feed pipe (4) are connected in sequence. The first discharge port (31) is provided with a first discharge valve (38) so that the opening and closing of the first discharge port (31) can be controlled by the first discharge valve (38). The screw conveyor (6) is used to control the output amount of the material to be crushed, and the transmitter (7) is used to make the material to be crushed conveyed evenly. And / or, the first discharge port (31) is connected to the screw conveyor (6) via a second hose (39).

5. The airflow pulverizing system according to claim 1, characterized in that, The dual-channel nozzle (2) is also provided with a distributor (23), which is coaxially installed in the feed channel (21) and communicates with the feed channel (21) to reduce the turbulence of the powder material flow in the feed channel (21). The distributor (23) and the second section (222) of the air inlet channel (22) are arranged sequentially from the inlet of the feed channel (21) toward the nozzle. The cross-sectional area of ​​the distributor (23) gradually decreases along the direction from the inlet of the feed channel (21) toward the nozzle to accelerate the flow of powder material.

6. The airflow pulverizing system according to any one of claims 1-5, characterized in that, The nozzle of the air intake channel (22) is connected to the crushing chamber through a Laval nozzle (223). The Laval nozzles (223) are spaced apart on the inner circumference of the feed channel (21). Alternatively, the nozzle of the air intake channel (22) is in the form of a Laval nozzle (223) structure, so that the compressed airflow is injected into the crushing chamber at supersonic speed.

7. The airflow pulverizing system according to claim 6, characterized in that, The dual-channel nozzles (2) are multiple and arranged at intervals along the circumference of the pulverizing chamber; And / or, the inlet of the air inlet channel (22) of all the dual-channel nozzles (2) is connected through an air-bag ring pipe (24), which is sleeved on the outer periphery of the airflow pulverizer (1).

8. The airflow pulverizing system according to claim 1, characterized in that, The inlet of the air intake channel (22) is connected to a compressed air source via a heater (25) so that the compressed airflow is heated by the heater (25).

9. The airflow pulverizing system according to claim 1, characterized in that, It also includes a grading wheel (11), a receiving hopper (8) and a dust collector (81) connected in sequence. The grading wheel (11) is connected to the crushing chamber and is used to screen powder materials of different particle sizes. The receiving hopper (8) is used to temporarily store powder materials with qualified particle sizes and is provided with a second discharge port (82). The second discharge port (82) is equipped with a second discharge valve (83) and is suitable to be connected to the discharge tank (84). The second discharge valve (83) is used to control the opening and closing of the second discharge port (82). The dust collector (81) is used to separate powder materials with qualified particle sizes and gas. And / or, the receiving hopper (8) is further provided with a second weighing unit (85), which is used to weigh the receiving hopper (8) so that when the weight of the receiving hopper (8) reaches a set value, the powder material is discharged from the second discharge port (82).

10. The airflow pulverizing system according to claim 9, characterized in that, It also includes an induced draft fan (9), which is connected to the dust collector (81). The induced draft fan (9) can create a slight negative pressure in the crushing chamber so that the powder material with qualified particle size can pass through the classifying wheel (11).

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