Negative pressure and dry grinding process coupling working method for high-precision particle size screening

Abstract

The invention discloses a negative pressure and dry grinding process coupling working method for high-precision particle size screening, relates to the technical field of dry grinding, and aims at improving the subsequent material separation process according to the basic principle of the dry grinding process and aiming at the temperature change of a grinding environment. According to the essence of the material separation process, materials with corresponding particle sizes and grinding media are separated through screens with corresponding pore diameters, firstly, a material receiving disc is additionally arranged in cooperation with vortex airflow, and the material receiving disc aims at preventing the materials from being excessively concentrated to affect the material screening process on the basis that it is guaranteed that the materials are fully diffused; specifically, the rubber layer can change the radian direction, the diffusion degree of fine grinding materials driven under the vortex effect is increased, and the real-time temperature change of inert gas in the grinding process and the separation process can be essentially used as a judgment basis in the grinding process. The key content is that the temperature of the grinding environment in the grinding machine is changed in real time on the basis of ensuring continuous flowing of inert gas.

Description

Technical Field

[0001] The invention relates to the technical field of dry grinding, and in particular to a working method of coupling negative pressure for high-precision particle size screening with a dry grinding process. Background Art

[0002] The principles of dry grinding are basically similar to those of wet grinding. Its advantages are that there is no drying process, high efficiency and low energy consumption, etc., and from the perspective of grinding accuracy: after the material is ground, it is screened according to the particle diameter, and the material that meets the requirements is discharged and collected, and the material that does not meet the requirements is returned to the grinding mechanism for re-grinding. Please refer to the relevant content in publication numbers CN111484026A and CN1559692A.

[0003] The basic structure of particle screening is a screen structure with corresponding aperture, in which there is bound to be a clogging problem. However, it is important to note that: considering the particularity of the material, there is no lubricating and buffering effect of the liquid medium between the grinding material / medium, which leads to temperature changes in the actual grinding environment. The continuously accumulated temperature will aggravate the wear of the grinding medium (zirconium beads) and will also change the environmental pressure inside the grinding structure. In addition, the grinding material is prevented from being oxidized by pumping inert protective gas. Therefore, in the screening cycle of the mixed material, there are obvious fluctuations in the ambient temperature and ambient pressure in the grinding structure and the screening structure, especially the pressure changes therein directly affect the screening process and the "flow" process of the material, such as: the mixed material enters the screening structure from the grinding structure, the internal environmental pressure of the grinding structure is much greater than the internal environmental pressure in the screening structure, and the mixed material is filled into the screening structure at high speed, affecting the inert protective environment inside the grinding structure, directly affecting the filtering effect and the screening cycle effect.

[0004] The present invention proposes a solution to this problem. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for coupling negative pressure with a dry grinding process for high-precision particle size screening. The method is aimed at the material particle size screening process in the dry grinding process, and takes into account the temperature / pressure changes in the grinding action. During the actual screening cycle, it directly affects the inert protective environment in the grinding equipment and also indirectly affects the screening process.

[0006] The object of the present invention can be achieved by the following technical solution: a method for coupling a negative pressure and dry grinding process for high-precision particle size screening, using a grinder, a separation drum and an air pump, a mixed material is obtained by the grinding action of the grinder, the mixed material enters the separation drum for separation action to obtain finely ground material and coarsely ground material, and the finely ground material is directly collected and the coarsely ground material is returned to the grinder for secondary grinding action, and an atmosphere temperature balance system is established by the air pump during the separation action;

[0007] The atmosphere environment temperature balance system includes an airflow forward blowing stage in the grinder and an airflow backflow stage in the separation cylinder, and obtains the gas temperature in the airflow forward blowing stage and the airflow backflow stage as well as the grinding environment temperature of the grinder. An indirect cooling component is added in the airflow backflow stage to control the start-up cycle of the airflow forward blowing stage according to the gas temperature of the grinder.

[0008] It is further configured as follows: a sieve cylinder is installed on the inner wall of the separation cylinder, and a mixing port and a discharge port are respectively provided at the upper and lower ends of the outer wall of the separation cylinder, a return port is provided at the lower end of the sieve cylinder, and a sieve port is provided at the outer wall position inside the separation cylinder.

[0009] It is further configured as follows: a movable plate and a fixed plate are respectively arranged at the upper end of the screen drum along the direction from top to bottom, the movable plate maintains a sliding motion in the inner wall of the separation drum, and multiple groups of spring guide rods are arranged between the movable plate and the fixed plate, and the fixed plate maintains a fixed connection with the upper end of the screen drum and the inner wall of the separation drum.

[0010] It is further configured as follows: an electric push rod is installed at the upper end of the separation cylinder, the output shaft of the electric push rod passes downward into the interior of the separation cylinder and is installed with a conical block corresponding to the moving disk, the mixing port corresponds to the upper side position of the moving disk, and a fixed rod corresponding to the conical block is installed at the center point of the bottom end of the inner wall of the screen cylinder, a sliding action is maintained between the conical block and the upper end of the fixed rod, and multiple sets of receiving trays are provided on the fixed rod.

[0011] It is further configured as follows: the diameters of the receiving plate and the screen cylinder decrease from top to bottom, the screen cylinder is provided with an air outlet corresponding to the air pump at the upper end of the return port, the air outlet is arranged in a circular array along the fixed rod, and the air outlet is inclined in the horizontal and vertical directions.

[0012] It is further configured as follows: the receiving tray is composed of a rubber layer and a fixed arc tray, the fixed arc tray is fixedly connected to the fixed rod, and the cross section of the fixed arc tray is in a downward curved arc shape, and the rubber layer is installed at the outer edge of the fixed arc tray.

[0013] It is further configured that: the outer edge of the rubber layer and the inner wall of the screen drum are in two states: contact or non-contact.

[0014] It is further configured that: the grinding action and the separation action are performed or stopped synchronously, and the operation process of the grinding action and the separation action includes the following contents:

[0015] Action 1: Set the upper limit temperature of grinding during the grinding action. When the grinding environment temperature is greater than or equal to the upper limit temperature, the grinding and separation actions are stopped simultaneously and enter the positive air flow stage. The air pump is used to pump inert gas into the grinder, and the mixed material is introduced into the separation cylinder through the inert gas.

[0016] Action 2: After the airflow positive feeding stage is completed, it enters the airflow backflow stage. The air pump continuously pumps inert gas into the screen drum through the air port, and completes the separation of finely ground materials and coarsely ground materials through the screen port and the receiving tray. The finely ground materials and coarsely ground materials are discharged from the discharge port and the return port respectively.

[0017] Action 3: When the finely ground material is recovered through the discharge port, the inert gas pumped in by the tuyere is collected simultaneously, and the recovered inert gas is cooled through the indirect cooling component. Finally, the inert gas that has completed the cooling action is used as the gas source in the positive blowing stage of the airflow.

[0018] The present invention has the following beneficial effects:

[0019] 1. Based on the dry grinding process and in conjunction with the subsequent separation process of mixed materials, the essence of the separation process is to separate materials of corresponding particle sizes and grinding media through screens of corresponding apertures. To this end, improvements are made to the material separation process, using vortex airflow to drive the full diffusion of the mixed materials, thereby limiting the diameter change of the screen drum and adding a receiving tray. On the one hand, the receiving tray can prevent excessive concentration of materials from affecting the material diffusion and separation process, and on the other hand, it can also generate internal negative pressure through the vortex gas to improve the diffusion degree of the finely ground materials;

[0020] 2. The key content of the present invention is reflected in the temperature change in the grinding environment. First, the overall grinding state can be judged according to the temperature change of the grinding environment. It can also be used as the starting cycle of the separation action and the grinding action. In the subsequent separation action, when the vortex gas is formed with inert gas, the inert gas provided is a relatively low-temperature gas. Its purpose is to cool the mixed material after the grinding is completed. The key is to control the temperature of the inert gas introduced into the separation cylinder and return the cooled inert gas to the grinding environment. In this way, the temperature of the grinding environment is indirectly controlled to avoid excessive temperature affecting the grinding quality of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a schematic diagram of the structure of the grinding machine in the method of coupling negative pressure and dry grinding process for high-precision particle size screening proposed by the present invention;

[0023] Figure 2This is a schematic diagram of the structure of the separation cylinder in the method of coupling negative pressure and dry grinding process for high-precision particle size screening proposed by the present invention;

[0024] Figure 3 For the present invention Figure 2 sectional view of

[0025] Figure 4 for Figure 2 The cross-sectional view of the corresponding screen drum;

[0026] Figure 5 It is a cross-sectional view of the receiving tray in the separation cylinder.

[0027] In the figure: 1. Grinding machine; 2. Separating cylinder; 201. Mixing port; 202. Discharging port; 203. Return port; 3. Screen cylinder; 4. Electric push rod; 5. Moving plate; 6. Fixed plate; 7. Air outlet; 8. Conical blocking block; 9. Fixed rod; 10. Spring guide rod; 11. Receiving plate; 1101. Rubber layer; 1102. Fixed arc plate. DETAILED DESCRIPTION

[0028] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] Example 1: Targeting the particle size screening process in the dry grinding process, and taking into account the temperature / pressure changes during the grinding action, the actual screening cycle directly affects the inert protective environment in the grinding equipment and also indirectly affects the screening process. The following technical solution is proposed:

[0030] Reference Figures 1 to 5 In this embodiment, the high-precision particle size screening method is coupled with a negative pressure and dry grinding process, using a grinder 1, a separation drum 2, and an air pump. A mixed material is obtained through the grinding action of the grinder 1. The mixed material enters the separation drum 2 for separation to obtain finely ground material and coarsely ground material. The finely ground material is directly collected and the coarsely ground material is returned to the grinder 1 for secondary grinding. During the separation action, an air pump is used to establish an atmospheric temperature balance system.

[0031] The atmosphere environment temperature balance system includes an airflow forward blowing stage in the grinder 1 and an airflow backflow stage in the separation drum 2, and obtains the gas temperature in the airflow forward blowing stage and the airflow backflow stage as well as the grinding environment temperature of the grinder 1, and adds an indirect cooling component in the airflow backflow stage. The start-up cycle of the airflow forward blowing stage is controlled according to the gas temperature of the grinder 1, a sieve drum 3 is installed on the inner wall of the separation drum 2, and a mixing port 201 and a discharge port 202 are respectively provided at the upper and lower ends of the outer wall of the separation drum 2, a return port 203 is provided at the lower end of the sieve drum 3, and a sieve port is provided on the outer wall of the sieve drum 3 corresponding to the inner side of the separation drum 2.

[0032] Principle introduction: A brief explanation of the dry grinding process: its essence is to use the rotational action to drive the material to be fully stirred. In order to increase the shear force, hard materials can be added, taking zirconium beads as an example. However, when the materials collide with each other, the temperature continues to accumulate, and the grinding environment temperature continues to rise. Higher temperatures will directly affect the material properties or the life of the zirconium beads. In addition, it is impossible to fully grind all materials to a qualified state in one grinding cycle. Therefore, after completing a grinding cycle, the mixed material that has been ground once will be discharged for separation, and the material that meets the particle size requirements will be discharged. The material that does not meet the particle size requirements and the zirconium beads are returned to the grinding equipment for the next grinding cycle. This part is the conventional principle;

[0033] Furthermore, considering the material properties, inert gas protection is required during the grinding process. The essence of this is to completely replace the internal gas of the grinding environment with inert gas to prevent material oxidation. Therefore, when the mixed material is pumped into the subsequent separation equipment, inert gas is also required as the power gas source. The key content of the present invention is to cool the inert gas in the subsequent separation equipment to reversely control the atmospheric temperature in the grinding environment.

[0034] Example 2: Supplementary explanation of the subsequent material separation process based on Example 1:

[0035] A moving disc 5 and a fixed disc 6 are respectively provided at the upper end of the screen drum 3 in the direction from top to bottom. The moving disc 5 maintains a sliding action in the inner wall of the separation drum 2, and multiple groups of spring guide rods 10 are provided between the moving disc 5 and the fixed disc 6. The fixed disc 6 maintains a fixed connection with the upper end of the screen drum 3 and the inner wall of the separation drum 2. An electric push rod 4 is installed at the upper end of the separation drum 2. The output shaft of the electric push rod 4 passes downward through the interior of the separation drum 2 and is provided with a conical block 8 corresponding to the moving disc 5. The mixing port 201 corresponds to the upper side position of the moving disc 5. A fixed rod 9 corresponding to the conical block 8 is installed at the center point of the bottom end of the inner wall of the screen drum 3. The conical block 8 maintains a sliding action with the upper end of the fixed rod 9, and a spring guide rod 10 is provided on the fixed rod 9. There are multiple sets of receiving trays 11, and the diameters of the receiving trays 11 and the screen drum 3 decrease from top to bottom. The screen drum 3 is equipped with an air outlet 7 corresponding to the air pump at the upper end of the return port 203. The air outlet 7 is arranged in a circular array along the fixed rod 9, and the air outlet 7 is inclined in the horizontal and vertical directions. The receiving tray 11 is composed of a rubber layer 1101 and a fixed arc tray 1102. The fixed arc tray 1102 is fixedly connected to the fixed rod 9, and the cross-section of the fixed arc tray 1102 is in a downward curved arc shape. The rubber layer 1101 is installed at the outer edge of the fixed arc tray 1102, and the outer edge of the rubber layer 1101 and the inner wall of the screen drum 3 are in contact or non-contact states.

[0036] Solution Description: Refer to Figure 4 The separation process is described below, which specifically includes the following steps:

[0037] S1: The mixed material needs to be pumped out of the grinder 1 in a high-pressure form, which is specifically manifested in the positive airflow blowing stage. In essence, it will directly enter the upper space on the movable disc 5. In this state, the electric push rod 4 needs to drive the conical block 8 to move upward to completely block the movable disc 5. However, in the high-pressure state, the movable disc 5 has a downward movement state, and the conical block 8 will also move downward synchronously. Conversely, when the conical block 8 continues to move downward, the mixed material emerges from the center point of the movable disc 5 and enters the screen drum 3. The purpose is to use the relative movement amplitude of the conical block 8 and the movable disc 5 to reduce the pressure amplitude of the mixed material entering the inside of the screen drum 3, and the spring guide rod 10 is also used in conjunction with it to control the movement amplitude of the movable disc 5;

[0038] S2: The key point is that each receiving tray 11 and multiple air vents 7, when the air pump blows out the inert gas through the air vents 7, first limit the setting angle of each air vent 7, the purpose is to ensure that the airflow direction of the air vent 7 is tilted upward, and each air vent 7 is also tilted in the direction of the water, thereby forming a spiral upward airflow, driving the mixed material to fully diffuse, but the following actions are formed through the receiving tray 11:

[0039] S2-1: In the initial state, under the action of the vortex airflow, the rubber layer 1101 bends upward and its outer edge contacts the inner wall of the screen drum 3, which can be understood as: dividing the interior of the screen drum 3 into multiple independent spaces, and under the continuous action of the vortex airflow, the upward bending degree of the rubber layer 1101 is intensified without contacting the inner wall of the screen drum 3. The purpose is to avoid excessive concentration of the mixed material and affect the separation process on the basis of ensuring the diffusion of the mixed material. As the mixed material continues to accumulate on the receiving tray 11, the weight borne by the rubber layer 1101 increases, so that the rubber layer 1101 bends downward, and part of the mixed material falls into the next receiving tray 11;

[0040] S2-2: When performing the separation action, it is necessary to ensure that the moving disc 5 is in a closed state. Then, when the inert gas is continuously pumped into the air port 7, the inert gas can only flow out along the sieve holes and be discharged from the discharge port 202. More specifically, when the receiving tray 11 is in an upwardly bent state, the entire receiving tray 11 forms a "bowl shape", and under the action of the vortex airflow, a negative pressure environment is formed at the upper internal position of the entire receiving tray 11. Then the finely ground material therein will rise with the vortex gas and flow out from the sieve mouth, while the coarsely ground material or heavier zirconium beads are deposited at the bottom end of the sieve drum 3 under the action of gravity for storage, and the finely ground material flows out from the discharge port 202 with the inert gas and is collected, and the coarsely ground material and zirconium beads stored at the bottom end of the sieve drum 3 will also be returned to the grinder 1 under the action of the inert gas.

[0041] Example 3: The atmosphere temperature balancing system is described in combination with Example 1 and Example 2:

[0042] The grinding action and the separation action are performed or stopped synchronously, and the operation process of the grinding action and the separation action includes the following contents:

[0043] Action 1: During the grinding action, an upper limit temperature is set. When the grinding environment temperature is greater than or equal to the upper limit temperature, the grinding and separation actions are stopped simultaneously and the process enters the positive airflow stage. An air pump is used to pump inert gas into the grinder 1, and the mixed material is introduced into the separation drum 2 through the inert gas.

[0044] Action 2: After the airflow feeding stage is completed, it enters the airflow backflow stage, and the air pump continuously pumps inert gas into the screen drum 3 through the air port 7, and completes the separation of finely ground materials and coarsely ground materials through the screen port and the receiving plate 11. The finely ground materials and coarsely ground materials are discharged from the discharge port 202 and the return port 203 respectively;

[0045] Action 3: When the finely ground material is recovered through the discharge port 202, the inert gas pumped in by the air port 7 is collected simultaneously, and the recovered inert gas is cooled through the indirect cooling component. Finally, the inert gas that has completed the cooling action is used as the gas source in the forward blowing stage of the airflow.

[0046] Solution description: The key content of the present invention is the flow direction of the inert gas during the material circulation process. For example, in the initial stage, the gas environment inside the grinder 1 and the separation drum 2 is completely replaced by inert gas, and a certain amount of inert gas is pumped into the grinding environment to maintain the pressure environment during the grinding action. Then, when the mixed material that has completed a grinding action is pumped into the separation drum 2, inert gas is also used as the gas source. However, the gas source of this part is essentially also derived from the separation drum 2. It can be indirectly understood that: a storage tank structure for storing inert gas is also provided between the separation drum 2 and the grinder 1. The separation drum 2, the grinding environment and the storage tank form a complete gas path. The inert gas in the positive blowing stage of the airflow comes from the storage tank. tank, and the inert gas in the storage tank comes from the inert gas blown out by the tuyere, but the tuyere 7 is also based on the inert gas in the storage tank, so it can be directly understood that: the interiors of the separation cylinder 2, the grinding environment and the storage tank are all filled with inert gas. When executing the positive airflow blowing stage, the inert gas in the storage tank is drawn out to pump the mixed material into the separation cylinder 2, and the inert gas in the storage tank is also used as the gas source for the gas blown out of the tuyere 7. During the grinding and separation actions, the grinding environment and the interior of the separation cylinder are in a relatively closed state. Therefore, in the actual separation action, the storage tank and the interior of the separation cylinder 2 form independent circuits, and the finely ground material flows with the inert gas, and the finely ground material is settled while the inert gas is returned to the storage tank.

[0047] Finally, the stored coarsely ground material and zirconium beads will be returned to the grinder 1 with the inert gas inside the storage tank. However, in this process, the inert gas in the storage tank needs to be indirectly cooled. Water-cooled indirect heat exchange can be used, so that the mixed material can also be cooled during the separation action. The key is to cool the inert gas to a suitable temperature. Then, when part of the inert gas mixed with the coarsely ground material and zirconium beads is returned to the grinder 1, the grinding environment can also be cooled.

[0048] In summary: According to the basic principles of dry grinding technology, the subsequent material separation process is improved according to the changes in grinding environment temperature. The essence of the material separation process is to separate the materials and grinding media of corresponding particle sizes through the screen of corresponding aperture. The first is to add a receiving plate in conjunction with the vortex airflow. Its purpose is to avoid excessive concentration of materials and affect the material screening process on the basis of ensuring sufficient diffusion of materials. It is specifically reflected in the rubber layer that can change the arc direction and increase the degree of diffusion of finely ground materials under the action of the vortex. Secondly, the real-time temperature change of the inert gas during the grinding and separation process can be used as a basis for judgment in the grinding process, but the key content is to change the grinding environment temperature inside the grinder in real time on the basis of ensuring the continuous flow of inert gas.

[0049] The above contents are merely examples and explanations of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0050] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these 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 any one or more embodiments or examples.

[0051] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for coupling negative pressure with dry grinding process for high-precision particle size screening, using a grinder (1), a separation cylinder (2) and an air pump, characterized in that: A mixed material is obtained by the grinding action of the grinder (1), and the mixed material enters the separation drum (2) for separation to obtain finely ground material and coarsely ground material, and the finely ground material is directly collected and the coarsely ground material is returned to the grinder (1) for secondary grinding. During the separation action, an air pump is used to establish an atmospheric temperature balance system; The atmosphere environment temperature balance system includes an airflow forward blowing stage in a grinder (1) and an airflow back-blowing reflux stage in a separation cylinder (2), and obtains the gas temperatures in the airflow forward blowing stage and the airflow back-blowing reflux stage as well as the grinding environment temperature of the grinder (1). An indirect cooling component is added in the airflow back-blowing reflux stage, and the start-up cycle of the airflow forward blowing stage is controlled according to the gas temperature of the grinder (1).

2. The method for coupling negative pressure and dry grinding process for high-precision particle size screening according to claim 1 is characterized in that: A sieve drum (3) is installed on the inner wall of the separation drum (2), and a mixing port (201) and a discharge port (202) are respectively provided at the upper and lower ends of the outer wall of the separation drum (2). A return port (203) is provided at the lower end of the sieve drum (3), and the sieve drum (3) has a sieve port corresponding to the outer wall inside the separation drum (2).

3. The method for coupling negative pressure and dry grinding process for high-precision particle size screening according to claim 2 is characterized in that: A movable plate (5) and a fixed plate (6) are respectively arranged at the upper end of the sieve drum (3) in a direction from top to bottom. The movable plate (5) maintains a sliding motion in the inner wall of the separation drum (2). A plurality of groups of spring guide rods (10) are arranged between the movable plate (5) and the fixed plate (6). The fixed plate (6) maintains a fixed connection with the upper end of the sieve drum (3) and the inner wall of the separation drum (2).

4. The method for coupling negative pressure and dry grinding process for high-precision particle size screening according to claim 3 is characterized in that: An electric push rod (4) is installed at the upper end of the separation cylinder (2). The output shaft of the electric push rod (4) passes downward into the interior of the separation cylinder (2) and is installed with a conical block (8) corresponding to the moving disk (5). The mixing port (201) corresponds to the upper side of the moving disk (5). A fixed rod (9) corresponding to the conical block (8) is installed at the center point of the bottom end of the inner wall of the sieve cylinder (3). The conical block (8) maintains a sliding action with the upper end of the fixed rod (9), and a plurality of groups of receiving trays (11) are provided on the fixed rod (9).

5. The method for coupling negative pressure and dry grinding process for high-precision particle size screening according to claim 4 is characterized in that: The diameters of the receiving tray (11) and the sieve drum (3) decrease from top to bottom. The sieve drum (3) is provided with an air outlet (7) corresponding to an air pump at the upper end of the return port (203). The air outlet (7) is arranged in a circular array along the fixed rod (9), and the air outlet (7) is arranged obliquely in the horizontal and vertical directions.

6. The method for coupling negative pressure and dry grinding process for high-precision particle size screening according to claim 6 is characterized in that: The receiving plate (11) is composed of a rubber layer (1101) and a fixed arc plate (1102). The fixed arc plate (1102) is fixedly connected to the fixed rod (9), and the cross section of the fixed arc plate (1102) is in a downwardly curved arc shape. The rubber layer (1101) is installed at the outer edge of the fixed arc plate (1102).

7. The method for coupling negative pressure and dry grinding process for high-precision particle size screening according to claim 6, characterized in that: There are two states between the outer edge of the rubber layer (1101) and the inner wall of the screen drum (3): contact or non-contact.

8. The method for coupling negative pressure and dry grinding process for high-precision particle size screening according to claim 7, characterized in that: The grinding action and the separation action are performed or stopped synchronously, and the operation process of the grinding action and the separation action includes the following contents: Action 1: During the grinding action, an upper limit temperature is set. When the grinding environment temperature is greater than or equal to the upper limit temperature, the grinding action and the separation action are stopped simultaneously and the process enters the positive air flow blowing stage. An air pump is used to pump inert gas into the grinder (1), and the mixed material is introduced into the separation cylinder (2) through the inert gas. Action 2: After the airflow feeding stage is completed, the airflow enters the airflow backflow stage, and the air pump continuously pumps inert gas into the screen drum (3) through the air port (7), and the fine-ground material and the coarse-ground material are separated through the screen port and the receiving plate (11). The fine-ground material and the coarse-ground material are discharged from the discharge port (202) and the return port (203) respectively; Action 3: When the finely ground material is recovered through the discharge port (202), the inert gas pumped in by the air port (7) is collected simultaneously, and the recovered inert gas is cooled through the indirect cooling component. Finally, the inert gas that has completed the cooling action is used as the gas source in the positive blowing stage of the air flow.

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