Dry sand mill

Abstract

The invention discloses a dry-process sand mill, and relates to the technical field of material crushing and grinding, the dry-process sand mill comprises a machine body, the machine body is provided with a feeding device, a grinding device, a discharging device and a driving device, the grinding device comprises a stirring shaft which is rotatably arranged, the stirring shaft is provided with a stirring assembly, and the stirring assembly is provided with a feeding device and a discharging device. The stirring assembly comprises a plurality of stirring discs which are arranged at intervals in the axial direction of the stirring shaft, a plurality of uniformly arranged stirring blades are installed on the stirring discs in the circumferential direction, the working face of each stirring blade is of an arc-shaped structure, and the radian direction of each stirring blade is matched with the rotating direction of the stirring shaft; the invention provides a dry sand mill which comprises a plurality of axially arranged stirring discs and a plurality of stirring blades uniformly and circumferentially arranged on the stirring discs, and the working surface of each stirring blade is of an arc-shaped structure, so that aggregates can be effectively impacted, the condition that uncrushed coarse particles and fine particle aggregates exist in products is avoided, and the product quality is improved. And meanwhile, the uniformity of particle size distribution of the product is ensured.

Description

Technical Field

[0001] This invention relates to the field of material crushing and grinding technology, specifically to a dry sand mill. Background Technology

[0002] Sand mills are highly efficient ultrafine grinding and pulverizing equipment, widely used in coatings, inks, pigments, pharmaceuticals, food, electronic materials, and new energy fields. Traditional sand mills are mostly wet sand mills, requiring a liquid medium, which limits their application in materials sensitive to moisture or requiring complex subsequent drying processes. Dry sand mills, on the other hand, do not require a liquid medium and directly pulverize and grind solid dry powder materials. They offer advantages such as shorter process flow, lower energy consumption, and less environmental pollution, leading to a growing demand for them.

[0003] For example, the patent with authorization announcement number CN113171850B, authorization announcement date August 16, 2024, entitled "Dry Sand Mill," has an inner cylinder and a main shaft constituting the grinding chamber. The grinding chamber includes a pre-grinding chamber, a fine grinding chamber, and a precision grinding chamber. The main shaft in the pre-grinding chamber is equipped with stirring blades arranged circumferentially around the main shaft to form an axial spiral structure for feeding material into the fine grinding chamber. The main shafts in the fine grinding and precision grinding chambers are equipped with grinding blades arranged in pairs along the axial spacing of the main shaft, feeding material towards the discharge pipe. This invention divides the grinding chamber of the sand mill into a pre-grinding chamber, a fine grinding chamber, and a precision grinding chamber. The stirring blades and grinding blades drive the mixture of material and grinding media to generate relatively high-speed motion, achieving the grinding process. Due to the three-stage graded grinding, the material can be directly dry-ground to obtain a finer final product. This reduces the steps of adding water to the material before grinding and drying the material after grinding, simplifying the grinding process and making it suitable for grinding materials with high fineness requirements.

[0004] For example, patent CN212348955U, authorized on January 15, 2021, entitled "A Continuous Through-Type Dry Sand Mill for Ferrites," describes a device comprising a support frame, a material hopper, an electrical control cabinet, a motor, a feed inlet, a discharge outlet, an exhaust outlet, and a stirring section. The material hopper is cylindrical, and the hopper, electrical control cabinet, and motor are all mounted on the support frame, with the motor positioned above the hopper. The feed inlet and exhaust outlet are located at the top of the hopper, while the discharge outlet is at the bottom. The stirring section is located inside the hopper and connected to the output of the motor. This patented device overcomes the shortcomings of commonly used single dry mixing processes in the industry, such as uneven mixing and poor particle contact leading to incomplete reactions and the formation of additional phases. It ensures uniform mixing of various components, resulting in finer particles with close contact, thereby promoting solid-phase reactions during sintering and facilitating the production of high-performance sintered ferrite permanent magnet materials.

[0005] During the dry sand milling process, material particles are prone to agglomeration, which means that they adsorb each other in the grinding chamber to form agglomerates. These agglomerates are difficult to be effectively crushed by the grinding media and cannot meet the target ultrafine particle size requirements. This results in the product containing both uncrushed coarse particles and agglomerated fine particle aggregates, directly destroying the uniformity of the product particle size distribution. Summary of the Invention

[0006] The purpose of this invention is to provide a dry sand mill to overcome the above-mentioned shortcomings of the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A dry sand mill includes a machine body, on which a feeding device, a grinding device, a discharging device, and a driving device are provided. The grinding device includes a rotating stirring shaft, on which a stirring assembly is mounted. The stirring assembly includes a plurality of stirring discs spaced apart along the axial direction of the stirring shaft. A plurality of uniformly arranged stirring blades are mounted circumferentially on the stirring discs. The working surface of the stirring blades has an arc-shaped structure, and the arc direction of the stirring blades is adapted to the rotation direction of the stirring shaft.

[0008] In the aforementioned dry sand mill, the arc direction of the stirring blades is adapted to the rotation direction of the stirring shaft, and the stirring blades of two adjacent sets of stirring discs are staggered in the circumferential direction.

[0009] The aforementioned dry sand mill further includes a grinding cylinder fixed to the machine body, with a grinding media inlet on the upper side of the grinding cylinder and a grinding media outlet on the lower side of the grinding cylinder.

[0010] The aforementioned dry sand mill includes a feeding device comprising a hopper fixed to the upper end of the machine body, a feeding end on the grinding cylinder, a dispersant installed inside the hopper, and a feeding screw installed on the lower side of the hopper, the feeding screw being connected to the feeding end of the grinding cylinder.

[0011] In the aforementioned dry sand mill, the outlet end of the feed screw extends into the interior of the grinding cylinder, and the outlet direction of the feed screw forms a certain angle with the rotation direction of the stirring shaft.

[0012] The aforementioned dry sand mill includes a discharge device comprising a discharge screen pipe fixed at the end of the grinding cylinder away from the feeding device, wherein multiple screens are provided inside the discharge screen pipe.

[0013] The aforementioned dry sand mill includes a drive device comprising a drive motor mounted on the machine body, wherein the output shaft of the drive motor is connected to the stirring shaft via a coupling.

[0014] In the aforementioned dry sand mill, the surface of the stirring blades is coated with a zirconia ceramic coating.

[0015] In the aforementioned dry sand mill, the outer wall of the grinding cylinder is provided with a cooling jacket, the cooling jacket is provided with a coolant inlet and a coolant outlet, and flowing coolant is introduced into the cooling jacket to cool the grinding cylinder.

[0016] In the aforementioned dry sand mill, a vibrator is installed on the hopper to prevent material from clogging inside the hopper.

[0017] In the above technical solution, the present invention provides a dry sand mill, including multiple axially arranged stirring discs and multiple uniformly circumferentially arranged stirring blades on the stirring discs, and the working surface of the stirring blades is an arc-shaped structure, which can effectively impact agglomerates and avoid the situation where there are both uncrushed coarse particles and agglomerated fine particle aggregates in the product, while ensuring the uniformity of the particle size distribution of the product. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a three-dimensional structural diagram of a dry sand mill provided in one embodiment of the present invention.

[0020] Figure 2 This is a top view of a dry sand mill provided in one embodiment of the present invention.

[0021] Figure 3 For the present invention Figure 2 A magnified view of the area at point X.

[0022] Figure 4 This is a partial cross-sectional view of a dry sand mill provided in one embodiment of the present invention.

[0023] Figure 5 This is a partial three-dimensional structural schematic diagram of a grinding device provided in one embodiment of the present invention.

[0024] Figure 6 This is a partial three-dimensional structural schematic diagram of a grinding device provided in another embodiment of the present invention.

[0025] Figure 7 This is a partial three-dimensional structural diagram of the grinding device provided in another embodiment of the present invention.

[0026] Figure 8 This is a partial cross-sectional view of a grinding apparatus provided in another embodiment of the present invention.

[0027] Figure 9 For the present invention Figure 8 A magnified view of the area at point Y.

[0028] Figure 10 A cross-sectional view of the stirring blades provided in another embodiment.

[0029] Figure 11 A partial three-dimensional structural schematic diagram of a grinding apparatus provided in another embodiment.

[0030] Figure 12 A three-dimensional structural schematic diagram of the stirring blade provided for another embodiment.

[0031] Figure 13 A cross-sectional view of the stirring blades provided for another embodiment.

[0032] Explanation of reference numerals in the attached figures: 1. Machine body; 2. Feeding device; 21. Hopper; 22. Disperser; 23. Feeding screw; 3. Drive device; 4. Grinding device; 41. Stirring shaft; 42. Stirring assembly; 421. Stirring disc; 422. Stirring blades; 423. Grinding cylinder; 424. Rotating shaft; 425. Inner cylinder; 426. Annular movable groove; 427. Annular movable plate; 428. Drive gear; 429. Annular rack; 43. Annular grading plate; 431. Grading screen; 44. Vibration assembly; 441. Mounting groove; 442. Contact rod; 443. Vibration spring; 45. Storage port; 451. Receiving groove; 453. Baffle plate; 454. Connecting groove; 455. Sliding rod; 456. Mounting spring; 457. Fixing block; 458. Drive ring; 459. Fixing rod; 460. Arc-shaped extrusion block; 5. Discharge device. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] like Figure 1-13 As shown in the figure, a dry sand mill provided by the present invention includes a machine body 1. The machine body 1 is provided with a feeding device 2, a grinding device 4, a discharging device 5 and a driving device 3. The grinding device 4 includes a rotating stirring shaft 41. A stirring assembly 42 is installed on the stirring shaft 41. The stirring assembly 42 includes a plurality of stirring discs 421 arranged at intervals along the axial direction of the stirring shaft 41. A plurality of uniformly arranged stirring blades 422 are installed circumferentially on the stirring discs 421. The working surface of the stirring blades 422 has an arc-shaped structure.

[0035] Specifically, in this embodiment, the machine body 1 serves as the main mounting carrier for the dry sand mill, providing stable support for each functional device and ensuring coaxiality and structural stability during equipment operation. Without further elaboration, the machine body 1 is sequentially equipped with a drive device 3, a feeding device 2, a grinding device 4, and a discharging device 5. The installation positions of each device are precisely matched to the material flow path, ensuring continuous operation. The drive device 3 is mainly used to drive the grinding device 4 to grind the material, driving the stirring shaft 41 to rotate at high speed and smoothly, providing continuous and stable power for material grinding. The stirring component 42 of the grinding device 4 is key to achieving ultrafine material pulverization. The stirring component 42 is mainly used for stirring and grinding the material. The stirring disc 421 has a cylindrical structure, and preferably there are nine stirring discs 421. The stirring discs 421 are detachably fixed to the stirring shaft 41 by bolts to facilitate subsequent repair and replacement of damaged stirring blades 422. Preferably, the stirring discs 421 are evenly spaced along the axial direction of the stirring shaft 41. Preferably, there are four stirring blades 422. In this embodiment, the stirring blades 422 are designed with an arc-shaped structure. This structure not only enhances the impact and shearing effect on the grinding media and materials during rotation, improving grinding efficiency, but also continuously pushes the materials towards the discharge device 5 with the guiding force of the arc surface, achieving synchronous grinding and feeding, and ensuring production continuity. The arc direction of the stirring blades 422 is adapted to the rotation direction of the stirring shaft 41 to enhance the stirring effect on the grinding media and materials.

[0036] In another embodiment of the present invention, the stirring blades 422 of two adjacent sets of stirring discs 421 are staggered in the circumferential direction to avoid the material forming a fixed circulation in the grinding cylinder 423 and improve the uniformity of grinding. The stirring assembly 42 in this embodiment is uniquely designed. The stirring blades 422 adopt an arc-shaped working surface and are adapted to the rotation direction of the stirring shaft 41. At the same time, the staggered distribution of the blades of adjacent stirring discs 421 can greatly enhance the stirring intensity and uniformity of the grinding medium and material, avoid the local accumulation and circulation of material, significantly improve the grinding efficiency and grinding effect, and make the product particle size finer and more uniformly distributed.

[0037] In another embodiment of the present invention, the grinding device 4 further includes a grinding cylinder 423 fixed on the body 1. The grinding cylinder 423 has a grinding medium inlet on its upper side and a grinding medium outlet on its lower side. The grinding medium is zirconium oxide beads, alumina beads, or zirconium silicate beads, and its diameter is selected according to the feed particle size and the required output particle size of the material, usually 2-20 mm. More preferably, a grinding liner (not shown in the figure) is installed on the inner wall of the grinding cylinder 423. The function of the grinding liner is to protect the inner wall of the grinding cylinder 423 from wear by the grinding medium and the material, and at the same time, it works with the stirring component 42 and the grinding medium to enhance the impact, friction and shearing effect on the material, thereby improving the grinding effect.

[0038] In another embodiment of the present invention, the feeding device 2 includes a hopper 21 fixed to the upper end of the machine body 1, a feeding end is provided on the grinding cylinder 423, a dispersant 22 is installed in the hopper 21, and a feeding screw 23 is also installed on the lower side of the hopper 21. The feeding screw 23 is connected to the feeding end of the grinding cylinder 423. It also includes a feeding screw and a feeding motor (not shown in the figure). The feeding screw is driven by the feeding motor to realize quantitative and uniform feeding of materials.

[0039] In another embodiment of the present invention, the outlet end of the feed screw 23 extends into the interior of the grinding cylinder 423, and the outlet direction of the feed screw 23 forms a certain angle with the rotation direction of the stirring shaft 41 to promote rapid mixing of the material and the grinding medium. Specifically, during operation, the dry material to be ground is quantitatively conveyed from the hopper 21 to the feed screw 23 via the feed screw, and enters the grinding cylinder 423 at a certain speed and direction for grinding under the conveying action of the feed screw 23.

[0040] In another embodiment of the present invention, the discharge device 5 includes a discharge screen pipe fixed to one end of the grinding cylinder 423 away from the feeding device 2, and a plurality of screens are provided inside the discharge screen pipe to assist in the conveying and separation of materials.

[0041] In another embodiment of the present invention, the driving device 3 includes a drive motor mounted on the machine body 1. The output shaft of the drive motor is connected to the stirring shaft 41 via a coupling, providing continuous and stable power for the rotation of the stirring shaft 41. Specifically, during operation, when the dry material to be ground enters the grinding cylinder 423, the drive motor drives the stirring shaft 41 to rotate, thereby driving the stirring assembly 42 to rotate at high speed. At this time, the stirring blades 422 agitate the grinding media and materials in the grinding cylinder 423, causing strong impact, collision, friction and shearing effects between the grinding media, between the grinding media and the materials, and between the materials and the grinding liner, thereby crushing and grinding the materials.

[0042] In another embodiment of the present invention, the surfaces of the grinding liner and the stirring blade 422 are coated with a wear-resistant coating, which is a tungsten carbide or zirconium oxide ceramic coating, or a zirconium oxide or silicon carbide ceramic component, to improve its wear resistance and extend its service life.

[0043] In another embodiment of the present invention, a cooling jacket is provided on the outer wall of the grinding cylinder 423. The cooling jacket is provided with a coolant inlet and a coolant outlet. Coolant is introduced into the cooling jacket to cool the grinding cylinder 423 and prevent the material temperature from becoming too high due to frictional heat during the grinding process. Specifically, during operation, coolant is introduced into the cooling jacket during the grinding process to remove the heat generated during grinding through heat exchange and control the temperature inside the grinding cylinder 423.

[0044] In another embodiment of the present invention, a vibrator is provided on the hopper 21 to prevent material from clogging in the hopper 21; in addition, mechanical seals or skeleton oil seals are provided between the two ends of the grinding cylinder 423 and the stirring shaft 41 to ensure the sealing of the grinding cylinder 423 and prevent dust leakage.

[0045] Furthermore, this embodiment provides a new technical solution for the stirring assembly 42. In this embodiment, the stirring blade 422 is a fan-shaped plate structure, no longer an arc-shaped structure. This is to ensure the overall working strength of the stirring blade 422, as the arc-shaped stirring blade 422 is easily damaged during impact. In addition, the stirring disc 421 is still sleeved and installed on the outside of the stirring shaft 41. In this embodiment, the stirring blade 422 is not directly fixed to the stirring disc 421. The stirring disc 421 is circumferentially rotatably mounted with multiple rotating shafts 424. The number of rotating shafts 424 is preferably six and evenly spaced. The stirring blade 422 is fixed on the rotating shafts 424. In addition, an inner cylinder 425 is fixed on the inner wall of the grinding cylinder 423. The inner cylinder 425 has multiple annular movable grooves 426. 26 is configured in a one-to-one correspondence with the stirring plate 421. An annular movable plate 427 is rotatably mounted on the side of the annular movable groove 426 away from the grinding cylinder 423. The cross-section of the annular movable plate 427 is T-shaped to facilitate its limited movement within the annular movable groove 426. All rotating shafts 424 within the same stirring plate 421 are rotatably mounted on the annular movable plate 427, and the end of the rotating shaft 424 closest to the grinding cylinder 423 extends into the annular movable groove 426. A drive gear 428 is fixed to the end of the rotating shaft 424 located in the movable groove. An annular rack 429 is also fixed to the side wall of the annular movable groove 426. The drive gear 428 and the annular rack 429 mesh with each other. When the stirring shaft 41 rotates, the drive gear 428 rotates under the drive of the annular rack 429, thereby driving the rotating shaft 424 to rotate.In operation, the drive motor rotates the stirring shaft 41, causing multiple stirring discs 421 to rotate synchronously and drive multiple rotating shafts 424 to perform circular motion. The movement of the rotating shafts 424 also causes the annular movable plate 427 to rotate within the annular movable groove 426. Simultaneously, the rotation of the rotating shafts 424 drives the drive gear 428 to perform circular motion. Since the drive gear 428 meshes with the annular rack 429, the drive gear 428 rotates, causing the rotating shaft 424 to rotate as well. This rotation of the rotating shaft 424 causes the stirring blades 422 to rotate synchronously, allowing the sides of the stirring blades 422 to contact the material. This breaks up the fixed circulation and localized accumulation of the material, enhancing the impact and shearing force against agglomerates. This design allows for more thorough contact between the grinding media and the material, resulting in more uniform force distribution and preventing the residue of coarse particles and secondary agglomeration of fine particles. This improves the ultrafine grinding effect and the uniformity of the product particle size distribution. In addition, the rotation of the stirring blades 422 can also propel the material within the horizontally positioned grinding cylinder 423. This not only facilitates passive grading of the material but also promotes its exit from the chamber. Compared to the arc-shaped stirring blades 422, the rotation of the stirring blades 422 is significantly more effective in preventing material accumulation at the feed end. In summary, the passive rotation of the stirring blades 422 serves two functions: firstly, it ensures more thorough contact with the material, resulting in a better impact on agglomerated materials; secondly, it effectively propels the material within the grinding cylinder 423, facilitating grading and exit from the chamber.

[0046] Furthermore, an annular grading plate 43 is fixed in the middle of the inner wall of the inner cylinder 425. The number of annular grading plates 43 is not less than one, preferably two. A grading screen 431 is installed on the annular grading plate 43. The grading screen 431 is used for screening materials. Multiple grading holes are opened on the grading screen 431. The diameter of the grading holes on the grading screen 431 closer to the discharge device 5 is smaller. In this embodiment, a vibration assembly 44 is installed on the stirring blade 422 on the side closer to the grading screen 431 (there are stirring blades 422 on both sides of the grading screen 431; in this embodiment, it specifically refers to the stirring blade 422 on the side farther from the discharge device 5). The vibration assembly 44 includes multiple mounting slots 441 formed on the side wall of the stirring blade 422 near the grinding cylinder 423. A contact rod 442 is slidably mounted within each mounting slot 441. The end of the contact rod 442 away from the stirring blade 422 is arc-shaped. The contact rod 442 has a circular rod-like structure, and its diameter is larger than the diameter of the grading screen holes on the adjacent grading screen 431. That is, the contact rod 442 will not insert into the grading screen holes. A vibration spring 443 connects the contact rod 442 to the mounting slot 441. The contact rod 442 and the grading screen 431 are correspondingly fitted. When the rotating shaft 424 rotates, the contact rod 442 will interact with the grading screen. The screen 431 contacts and causes the grading screen 431 to vibrate; specifically, during operation, when the stirring shaft 41 rotates, the rotating shaft 424 also performs a circular motion and rotates. During the rotation of the rotating shaft 424, the stirring blades 422 also rotate. At this time, the rotation of the stirring blades 422 (on the side closer to the grading screen 431) causes the contact rod 442 to contact the grading screen 431. As the stirring blades 422 rotate, the contact rod 442 also rotates and is pressed into the mounting groove 441 by the grading screen 431. The vibration spring 443 is also compressed accordingly. When the stirring blades 422 continue to rotate, the contact rod 442 separates from the grading screen, and under the elastic action of the vibration spring 443... When the contact rod 442 is reset, it elastically strikes the grading screen 431, causing the grading screen 431 to vibrate and preventing it from being blocked by material. In this embodiment, the rotation of the stirring blade 422 passively causes the grading screen 431 to vibrate, thus preventing material blockage. The compound motion of the stirring blade 422 (combined by revolution around the stirring shaft 41 and rotation around the rotating shaft 424) has three functions: firstly, it allows for more thorough contact with the material, resulting in a better impact on agglomerated materials; secondly, it effectively propels the material within the grinding cylinder 423; and thirdly, it passively triggers the vibration of the grading screen 431.

[0047] Furthermore, due to gravity, the material tends to accumulate on the lower side of the inner wall of the grinding cylinder 423. This results in the material being discharged from the lower side of the discharge device 5, failing to fully utilize its overall conveying and separating efficiency. Excessive compression and blockage of the material at the lower side also affects the smoothness of discharge, hindering the overall grinding and discharge efficiency of the equipment. Therefore, this embodiment provides a further solution: multiple storage ports 45 are provided on the end face of the stirring blade 422, and receiving grooves 451 are provided on the side walls of the storage ports 45. The receiving grooves 451 communicate with the corresponding storage ports 45, and a baffle plate 453 is slidably installed within the receiving grooves 451. The structure is approximately square-shaped. Furthermore, the stirring blade 422 has a connecting groove 454, whose extension direction is the same as that of the rotating shaft 424. The connecting groove 454 is square-shaped, and multiple connecting grooves 454 are connected to the receiving groove 451. A sliding rod 455 is slidably installed within the connecting groove 454, and a mounting spring 456 connects the sliding rod 455 to the connecting groove 454. The baffle plate 453 is connected to the sliding rod 455 via a fixing block 457. Under the elastic action of the mounting spring 456, initially, the baffle plate 453 extends into the storage port 45 and partially blocks the storage port 45, thus allowing the storage port 45 to process some material. The sliding rod 455 extends beyond the stirring blade 422 at one end away from the stirring shaft 41. A driving ring 458 is mounted on the end of the sliding rod 455 outside the stirring blade 422. The driving ring 458 is slidably sleeved on the rotating shaft 424, and there is a certain gap between the driving ring 458 and the end of the stirring blade 422 away from the stirring shaft 41. This gap is defined as the movement gap, which allows the driving ring 458 to move towards the stirring shaft 41. In addition, in this embodiment, a fixing rod 459 is fixed on the upper side of the inner wall of the inner cylinder 425. An arc-shaped extrusion block 460 is fixed at the end of the fixing rod 459 near the stirring shaft 41. The arc-shaped extrusion block 460 is located away from the stirring shaft. One end of the 41 is arc-shaped, and the central axis of the virtual circle containing this arc coincides with the central axis of the stirring shaft 41. The end of the arc-shaped extrusion block 460 near the stirring shaft 41 is inclined, and the thickness of the arc-shaped extrusion block 460 gradually increases along the rotation direction of the stirring shaft 41. This is to compress the driving ring 458 at a specific position, moving it closer to the stirring shaft 41. The arc-shaped extrusion block 460 and the driving ring 458 are correspondingly fitted. When the rotating shaft 424 performs a circular motion and brings the driving ring 458 into contact with the arc-shaped extrusion block 460, the driving ring 458 will be compressed and moved closer to the stirring shaft 41. In addition, both the fixing rod 459 and the arc-shaped extrusion block 460 are located directly above the stirring shaft 41.This is so that when the stirring blades 422 move directly above the stirring shaft 41, some of the material in the storage port 45 is thrown out, allowing some material to be output from the top of the discharge device 5; specifically, during operation, As the stirring shaft 41 rotates, the stirring disc 421 also rotates synchronously and drives the stirring blades 422 to perform a circular motion. At this time, the material accumulated on the lower side of the inner wall of the grinding cylinder 423 will enter the storage port 45 on the end face of the stirring blades 422. Since the baffle plate 453 extends into the storage port 45 in the initial state, the storage port 45 blocks the material and completes the storage. When the stirring blade 422 moves to a position directly above the stirring shaft 41 as it revolves, the driving ring 458 on the outer side of the sliding rod 455 contacts the arc-shaped extrusion block 460 at the end of the fixed rod 459 on the upper side of the inner wall of the inner cylinder 425. As the stirring shaft 41 continues to rotate, the thickness of the arc-shaped extrusion block 460 gradually increases along the rotation direction. The inclined extrusion driving ring 458 on the arc-shaped extrusion block 460 moves towards the stirring shaft 41, thereby driving the sliding rod 455 to slide in the connecting groove 454 and compress the installation spring 456. At the same time, the baffle plate 453 moves synchronously with the sliding rod 455 and disengages from the storage port 45. At this time, the material stored in the storage port 45 is no longer obstructed and is thrown out to the upper area of ​​the grinding cylinder 423 (that is, in contact with the upper area of ​​the discharge device 5) under the action of the centrifugal force of the rotating stirring blade 422. This part of the material is finally output from the upper channel of the discharge device 5, realizing that the material is discharged from both the upper and lower sides of the discharge device 5, giving full play to the conveying and separation efficiency of the discharge device 5, and avoiding the situation where the material on the lower side is excessively squeezed and congested, affecting the smoothness of the discharge. Thus, in this embodiment, the compound motion of the stirring blade 422 is used to drive the material at the bottom to the upper side and then automatically throw it out under the action of centrifugal force. In summary, the compound motion of the stirring blade 422 has four functions: first, it makes more sufficient contact with the material and has a better impact effect on the agglomerated material; second, it can effectively promote the movement of the material in the grinding cylinder 423; third, it passively triggers the vibration of the grading screen 431; and fourth, it drives the material at the bottom to the upper side and then automatically throws it out under the action of centrifugal force.

[0048] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A dry sand mill, comprising a body, wherein a feeding device, a grinding device, a discharging device, and a driving device are disposed on the body, characterized in that, The grinding device includes a rotating stirring shaft, on which a stirring assembly is mounted. The stirring assembly includes multiple stirring discs spaced apart along the axial direction of the stirring shaft. Multiple uniformly arranged stirring blades are mounted circumferentially on the stirring discs. The working surface of the stirring blades is arc-shaped, and the arc direction of the stirring blades is adapted to the rotation direction of the stirring shaft.

2. A dry sand mill according to claim 1, characterized in that, The stirring blades of the two adjacent sets of stirring discs are staggered in the circumferential direction.

3. A dry sand mill according to claim 2, characterized in that, The grinding device also includes a grinding cylinder fixed on the machine body, with a grinding media adding port on the upper side of the grinding cylinder and a grinding media discharging port on the lower side of the grinding cylinder.

4. A dry sand mill according to claim 3, characterized in that, The feeding device includes a hopper fixed to the upper end of the machine body, a feeding end is provided on the grinding cylinder, a dispersant is installed in the hopper, and a feeding screw is also installed on the lower side of the hopper. The feeding screw is connected to the feeding end of the grinding cylinder.

5. A dry sand mill according to claim 4, characterized in that, The outlet end of the feed screw extends into the interior of the grinding cylinder, and the outlet direction of the feed screw forms a certain angle with the rotation direction of the stirring shaft.

6. A dry sand mill according to claim 1, characterized in that, The discharge device includes a discharge screen pipe fixed at the end of the grinding cylinder away from the feeding device, and multiple screens are installed inside the discharge screen pipe.

7. A dry sand mill according to claim 1, characterized in that, The driving device includes a drive motor mounted on the machine body, and the output shaft of the drive motor is connected to the stirring shaft by a coupling.

8. A dry sand mill according to claim 1, characterized in that, The surface of each stirring blade is coated with a zirconia ceramic coating.

9. A dry sand mill according to claim 8, characterized in that, The outer wall of the grinding cylinder is provided with a cooling jacket, which has a coolant inlet and a coolant outlet. Coolant flows through the cooling jacket to cool the grinding cylinder.

10. A dry sand mill according to claim 4, characterized in that, The hopper is equipped with a vibrator to prevent material from clogging inside the hopper.

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