A pre-grinding device

Abstract

The application discloses a pre-grinding device, and belongs to the technical field of grinding. The pre-grinding device comprises a rack, a grinding assembly and a filtering assembly. The grinding assembly comprises a rotating shaft driven by a motor, a rotating shearing disc and a plurality of stirring discs fixed on the shaft. An annular machine shell is arranged above the motor, and a fixed shearing disc opposite to the rotating shearing disc is fixed to the top of the annular machine shell. The top of the rotating shearing disc is provided with a plurality of stepped protrusions, and the bottom of the fixed shearing disc is provided with corresponding recesses. The rotating shearing disc and the fixed shearing disc form a grinding gap with a gap gradually decreasing from inside to outside layer by layer, and the side walls of each layer are provided with shearing grooves staggered with each other. The material is firstly subjected to multi-stage shearing and crushing between the two discs, then enters the annular machine shell, and is further ground by the grinding medium driven by the stirring discs, and finally is separated by a filter element and discharged. The pre-grinding device integrates efficient pre-shearing and medium grinding, significantly improves the crushing capacity of high-hardness impurities, thereby reducing the number of subsequent grinding devices, reducing energy consumption and cost, and improving the fineness and uniformity of products.

Description

Technical Field

[0001] This invention relates to a pre-grinding device, belonging to the field of grinding technology. Background Technology

[0002] Grinding technology is widely used in mining, chemical, and material preparation fields. In particular, in the processing of ores and solid materials, it is often necessary to grind the raw materials to a specific particle size in order to improve their reactivity, dissolution rate or meet the requirements of downstream processes. At present, sand mills are commonly used as the main fine grinding equipment in the industry.

[0003] Traditional grinding processes mainly rely on multiple sand mills operating in series. The working principle is that a high-speed rotating agitator drives the grinding media (such as zirconium beads, steel balls, etc.) to generate violent and disordered movement in a closed cavity. The material particles are gradually broken and ground by the random squeezing, collision and friction between the media and between the media and the cavity and the material. However, the effective shear force generated by this grinding mechanism based on media collision is relatively weak.

[0004] In actual production, especially when processing mineral materials with complex compositions, the materials often contain crystals or fine impurity particles with a hardness significantly higher than the main material. Existing sand mills rely on a relatively flexible collision-based crushing method, which is obviously insufficient for grinding these high-hardness micro-particles. It is difficult to effectively grind them to the target particle size in one or a few passes. Therefore, in order to ensure that the overall fineness of the final product is up to standard, it is often necessary to repeatedly pass the material through a series of sand mill units for cyclic grinding.

[0005] This traditional series of grinding processes has several significant drawbacks, including: insufficient overall grinding efficiency; relatively high equipment investment and operating costs; considerable room for improvement in the particle size uniformity and quality of the resulting products; poor energy consumption control and environmental performance during production; and insufficient controllability and flexibility in adjusting the process parameters of the entire system. Specifically:

[0006] 1. Low grinding efficiency: It has a weak ability to crush high-hardness impurities, the grinding time is long, and the output per unit of energy consumption is low.

[0007] 2. High investment and operating costs: large equipment investment, high energy consumption, and high operating costs of grinding media and cooling systems.

[0008] 3. Long production cycle: Multiple grinding cycles result in long processing time and low production capacity.

[0009] 4. Poor particle size uniformity: The collision and grinding process is highly random, resulting in a wide particle size distribution and poor quality stability.

[0010] 5. Frequent equipment wear and maintenance: The medium and lining are severely worn, resulting in a high failure rate and a large workload for maintenance.

[0011] 6. Automation level and human dependence: Multi-machine serial management is complex and highly dependent on human monitoring.

[0012] 7. High risk of metal contamination: Wear and tear generates metal shavings that may get mixed into the product, requiring an additional impurity removal process.

[0013] 8. Extremely low effective energy utilization rate: most of the energy is consumed in ineffective collisions and heat generation, and the proportion of fragmentation energy is relatively low.

[0014] 9. Poor process flexibility and adjustability: The series system has little room for adjustment and is difficult to adapt to the needs of flexible production of multiple varieties.

[0015] 10. The coexistence of "over-grinding" and "under-grinding" of materials: Uneven distribution of energy and residence time leads to some over-grinding and some under-grinding, resulting in poor product uniformity.

[0016] 11. The system occupies a large area and has complex pipelines: multiple devices and pipelines occupy a large space, and the infrastructure and cleaning and maintenance costs are high.

[0017] 12. Noise and heat management issues are prominent: multi-machine operation generates a lot of noise and heat, resulting in high cooling costs and affecting heat-sensitive materials.

[0018] 13. Difficulty in scaling up the process and reliance on experience: parameters are nonlinearly related, and scaling up cannot be directly calculated proportionally, resulting in high trial-and-error costs and long cycles. Summary of the Invention

[0019] The purpose of this invention is to provide a pre-grinding device to solve the problems mentioned in the background art.

[0020] To achieve the above objectives, the present invention adopts the following technical solution:

[0021] Compared with the prior art, the present invention designs a pre-grinding device, including a frame, on which a grinding component is installed, and a filter component is provided inside the grinding component;

[0022] The grinding assembly includes a motor, and a rotating shaft is fixed to the output shaft end of the motor;

[0023] A rotating shearing disk is fixed on the top outer periphery of the rotating shaft;

[0024] An annular housing is fixed to the upper side of the motor, and a fixed shearing disc is fixed to the top of the annular housing.

[0025] Several agitator discs are fixed on the outer circumference of the rotating shaft.

[0026] Furthermore, the fixed shearing disc includes a feed hole at its top, and the fixed shearing disc is located above the rotating shearing disc and the two are arranged opposite each other;

[0027] When the rotating shearing disc rotates, it cooperates with the fixed shearing disc to perform multi-directional, no-dead-angle, step-by-step rigid shearing and grinding on the material.

[0028] Furthermore, the top of the rotating shearing disk has a multi-layered stepped disk-shaped protrusion structure that increases in height from the outside to the inside, and the bottom of the fixed shearing disk has a multi-layered stepped disk-shaped concave structure that deepens in depth from the outside to the inside. The protrusions of the rotating shearing disk and the concave parts of the fixed shearing disk are spaced apart in both the axial and radial directions, thereby forming a grinding gap between the layers.

[0029] The rotating shearing disk has several first shearing grooves along the circumferential direction on the outer wall of each layer of protrusions.

[0030] The fixed shearing disc has several second shearing grooves arranged circumferentially on the inner wall of each layer of the recess.

[0031] Furthermore, the axial width and radial width of the grinding gap decrease layer by layer from the inner layer to the outer layer.

[0032] Furthermore, from the inner layer to the outer layer, the number of the first shear groove and the second shear groove increase layer by layer, and their widths decrease layer by layer.

[0033] Furthermore, the axial depth of the first shear groove in each layer is less than the protrusion height of the protrusion layer in which it is located;

[0034] Except for the innermost layer, the length of the first shear groove in each of the other layers, measured on a horizontal plane along a straight line pointing to the axis of rotation, is less than the radius difference between the protruding layer in which it is located and the adjacent inner protruding layer.

[0035] The axial depth of the second shear groove in each layer is less than the depth of the depression in the depression layer in which it is located.

[0036] Except for the outermost layer, the radial depth of the second shear groove in each of the remaining layers is less than the radius difference between the recessed layer in which it is located and the adjacent recessed layer.

[0037] Furthermore, the rotating shearing disk has a stepped hole at the top center, and the innermost first shearing groove communicates with the stepped hole;

[0038] The first shear groove is an inclined structure.

[0039] Furthermore, the interior of the annular housing is filled with grinding media, which, when the agitator rotates, work in conjunction with the grinding media to grind the sheared and ground material.

[0040] Furthermore, the grinding media is confined within the annular housing by the filter assembly, and the ground material is discharged through the filter assembly.

[0041] The filtration assembly includes a cylindrical filter element fixed to the inner wall of the annular housing, and an annular flow channel is formed between the cylindrical filter element and the inner wall of the annular housing. The side wall of the annular housing is provided with a discharge hole that communicates with the annular flow channel.

[0042] Furthermore, an inner cylinder is fixed on the inner wall of the annular housing, and a cooling chamber is formed between the inner cylinder and the inner wall of the annular housing. The annular housing is provided with a water inlet and a water outlet that communicate with the cooling chamber, and a spiral baffle is provided inside the cooling chamber.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] This invention, through innovative structural design, organically combines multi-stage shear grinding with media grinding. This not only effectively overcomes a series of inherent defects in traditional tandem sand grinding processes, but also brings significant technological advancements and outstanding substantial effects in terms of improved efficiency, reduced costs, improved quality, energy conservation and environmental protection, and enhanced process controllability. Specifically:

[0045] 1. This invention, by setting up a rotating shearing disk and a fixed shearing disk with a multi-layered stepped structure, and in conjunction with the first and second shearing grooves thereon, first performs strong, multi-directional, and dead-angle-free rigid shearing and grinding during the material falling process. This crushing mechanism dominated by shearing force has extremely high crushing efficiency for high-hardness crystals and fine impurities in materials, and can effectively grind them in one process, thereby greatly improving the overall grinding efficiency for complex materials and reducing the energy consumption per unit product.

[0046] 2. This invention integrates pre-shear grinding and subsequent media grinding into one device, achieving the effect of replacing multiple series sand mills with one device. This significantly reduces the initial purchase quantity of equipment, floor space, and investment in supporting pipelines and valves. At the same time, the efficient shear grinding reduces the load and time of subsequent media grinding, thereby reducing the overall power consumption, the frequency of replenishment of grinding media, and the operating cost of the cooling system, resulting in a significant reduction in overall operating costs.

[0047] 3. The material of this invention completes the entire process from coarse crushing, fine shearing to fine grinding in one continuous process in this equipment. The process is seamlessly connected, avoiding repeated pumping and waiting of materials between multiple equipment, thereby greatly shortening the overall processing time of a single batch of materials, speeding up the production rhythm, and improving the overall throughput capacity of the production line.

[0048] 4. This invention, through the design of a grinding gap that decreases layer by layer from the inside out, a shearing groove that increases in number and narrows layer by layer, and a groove structure that does not reach the edge, forces the material to pass through increasingly fine shearing areas step by step along a preset path. This forced and orderly step-by-step refining process ensures that the material particles are subjected to more uniform crushing action, thereby obtaining a final product with a narrower particle size distribution and significantly improved uniformity.

[0049] 5. The main crushing action of this invention occurs in the gaps and grooves of the shearing discs. This is a precise shearing action between rigid components. Compared with the irregular and violent collisions of the grinding media in the sand mill, it greatly reduces the impact wear on the grinding media and the equipment lining. Therefore, the loss rate of the grinding media and the replacement frequency of the equipment inner cylinder and filter screen are significantly reduced. The equipment operates more stably, the maintenance interval is extended, the downtime caused by maintenance is reduced, and the amount of equipment can be reduced, thus reducing the failure rate.

[0050] 6. This invention employs a highly integrated single-machine design, consolidating multi-stage grinding processes into one unit. Operators only need to centrally monitor and adjust the core parameters of a single machine to control the entire grinding process, completely eliminating the reliance on intensive manual labor for complex coordination, balancing, and individual monitoring of multiple connected devices. This greatly simplifies the operating interface, reduces the risk of human error, provides a solid foundation for fully automated and intelligent control of the production line, significantly improves the convenience and reliability of production management, and reduces the number of devices required, thus reducing manpower input.

[0051] 7. This invention significantly reduces the reliance on impact crushing. Under the premise of achieving the same fineness requirements, it can reduce the amount of high-hardness metal grinding media used. At the same time, it can greatly shorten the grinding time, fundamentally reducing the risk of introducing metal impurities into the product, and is more suitable for the production of high-purity products.

[0052] 8. The present invention uses rigid shearing to directly and efficiently apply mechanical energy to the material particles themselves for crushing. The energy transfer path is direct, and the energy consumption and heat generation from ineffective media collisions are greatly reduced. Therefore, the energy utilization efficiency of the present invention is much higher than that of traditional collision grinding methods. While achieving the same or better grinding effect, it realizes energy saving and consumption reduction.

[0053] 9. This invention allows for convenient adjustment of the shearing intensity of the shearing disc by adjusting the motor speed; the stepped structure itself provides multiple crushing intensity levels. This design enables a single device to more flexibly adapt to materials with different hardness and initial particle size. The grinding effect can be optimized by adjusting the process parameters, thereby improving the device's process adaptability and flexible production capacity.

[0054] 10. This invention, through a forced layer-by-layer graded grinding mechanism, ensures that materials of different particle sizes can receive appropriate and sufficient shearing action in their respective layers. High-hardness particles are effectively processed in the early shearing stage, preventing them from becoming under-ground particles due to difficulty in crushing in subsequent processes. At the same time, the orderly flow also prevents the over-grinding of fine particles that have already met the standards, thereby improving the overall quality consistency of the product.

[0055] 11. This invention adopts a highly integrated design, which integrates the pre-grinding and fine grinding functions into a compact housing. Compared with a series system consisting of multiple independent sand mills, pumps, intermediate tanks and complex pipelines, this equipment has a compact structure, small footprint, and extremely simplified external connection pipelines, which reduces installation complexity, cleaning difficulty and risk of cross-contamination.

[0056] 12. This invention uses a shear-based grinding method, which reduces the number of devices and thus generates significantly less operating noise than multiple sand mills that rely on impact, improving the working environment. In addition, the equipment integrates a high-efficiency cooling chamber composed of an inner cylinder and spiral baffles, which can directly, uniformly, and efficiently cool the grinding area, precisely control the material temperature, and avoid affecting product quality or causing thermal overload due to excessive temperature rise. At the same time, the cooling energy consumption is lower.

[0057] 13. The core crushing mechanism of this invention is based on a defined geometric structure (gap, shear groove) and rotational motion. Its crushing effect has a clearer physical relationship with parameters such as structural size and rotation speed. This more deterministic design principle makes the process scale-up from small laboratory machines to large industrial machines more reliable and predictable, reduces scale-up risks and over-reliance on experience, and shortens the development cycle of new products and processes. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0059] Figure 1 This is a frontal perspective view of the present invention;

[0060] Figure 2 This is a front-section three-dimensional structural diagram of the present invention;

[0061] Figure 3 The invention proposed Figure 2 A magnified schematic diagram of a portion of area A in the middle;

[0062] Figure 4 This is a schematic diagram of the internal structure of the annular casing proposed in this invention;

[0063] Figure 5 The invention proposed Figure 4 A magnified schematic diagram of a portion of region B in the middle section;

[0064] Figure 6 This is a schematic diagram of the rotating shear disk proposed in this invention;

[0065] Figure 7 This is a schematic diagram of the fixed shear disc structure proposed in this invention;

[0066] Figure 8 This is a table diagram illustrating the application of Embodiment 1 in this invention;

[0067] Figure 9 This is a table diagram illustrating the application of Embodiment 2 in this invention.

[0068] In the diagram: 1. Frame; 2. Motor; 3. Rotating shaft; 4. Rotating shearing disc; 5. Annular housing; 6. Fixed shearing disc; 7. Agitating disc; 8. First shearing groove; 9. Second shearing groove; 10. Stepped hole; 11. Cylindrical filter element; 12. Feed hole; 13. Inner cylinder. Detailed Implementation

[0069] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0070] Please see Figures 1-9 The present invention provides a technical solution:

[0071] A pre-grinding device includes a frame 1, a grinding assembly, and a filtering assembly.

[0072] The frame 1 serves as the supporting foundation for the entire equipment, on which the grinding assembly is fixedly installed. The grinding assembly mainly includes a drive section, a shearing grinding section, and a media grinding section.

[0073] Specifically, the drive unit includes a motor 2, which is fixedly mounted on the frame 1 by bolts.

[0074] In this embodiment, the motor 2 has a power of 30kW, and it is connected to an external power supply and controller via wires to realize start-stop and speed regulation.

[0075] The output shaft of motor 2 is set vertically upward, and a rotating shaft 3 is fixed to the end of its output shaft by a key.

[0076] Specifically, the rotating shaft 3 and the output shaft of the motor 2 are integrally forged to ensure the rigidity and coaxiality of the transmission.

[0077] The shearing and grinding section is located at the top of the equipment, and its core consists of a rotating shearing disc 4 and a fixed shearing disc 6.

[0078] The rotating shearing disc 4 is fixedly mounted on the top outer periphery of the rotating shaft 3 through the stepped hole 10 on its top, a key, and bolts, so that it can rotate at high speed together with the rotating shaft 3.

[0079] The fixed shearing disc 6 is fixedly installed on the top of the annular housing 5.

[0080] The annular housing 5 is a vertically placed cylindrical structure that is fixed to a housing above the frame 1 by bolts.

[0081] The motor 2 is located directly below the annular housing 5, that is, the annular housing 5 is fixed on the upper side of the motor 2.

[0082] A feed hole 12 is provided at the top center of the fixed shearing disc 6. A feed pipe is connected to the feed hole 12 and is fixed to the upper surface of the fixed shearing disc 6 for feeding materials.

[0083] The fixed shearing disk 6 is located directly above the rotating shearing disk 4, with the two positioned vertically opposite each other and spaced apart.

[0084] The center of the fixed shearing disk 6 coincides with the center of the rotating shearing disk 4 and the axis of the rotating shaft 3.

[0085] The material falls into the feed hole 12 and first reaches the central area of ​​the rotating shearing disc 4.

[0086] To achieve efficient, multi-stage shearing and grinding, the rotating shearing disk 4 and the fixed shearing disk 6 employ a special multi-layered stepped mating structure, specifically:

[0087] like Figure 6 As shown, the top of the rotating shearing disk 4 (i.e. the side facing the fixed shearing disk 6) is processed into a multi-layered concentric stepped disk-shaped protrusion structure. These protrusion layers increase in height from the outside to the inside (i.e. from the edge of the disk to the center), forming a structure similar to steps.

[0088] Accordingly, such as Figure 7 As shown, the bottom of the fixed shearing disk 6 (i.e. the side facing the rotating shearing disk 4) is processed into a multi-layered concentric stepped disk-shaped recessed structure that is complementary to the rotating shearing disk 4. These recessed layers deepen from the outside to the inside.

[0089] After assembly, the rotating shearing disk 4 matches the fixed shearing disk 6. The protrusions of the rotating shearing disk 4 are located exactly in the recesses of the fixed shearing disk 6, but the two maintain a small interval in both the axial and radial directions, so that an annular grinding gap is formed between each protrusion and recess. These grinding gaps together constitute the channel through which the material is sheared step by step.

[0090] To further enhance the shearing effect, several first shearing grooves 8 are uniformly formed circumferentially on the outer wall of each layer of the rotating shearing disk 4.

[0091] Similarly, on the inner wall of each recess of the fixed shearing disc 6, a number of second shearing grooves 9 are evenly provided in the circumferential direction.

[0092] When the rotating shearing disc 4 rotates at high speed, the first shearing groove 8 and the fixed second shearing groove 9 on it will periodically intersect, align and then separate, thereby generating strong shearing, tearing and impact on the material in the gap, realizing rigid shearing and grinding. Moreover, the rotating shearing disc 4 and the fixed shearing disc 6 can generate grinding in the axial direction, radial direction and gap, thus enabling multi-directional shearing and grinding.

[0093] To achieve progressive grinding of materials from coarse to fine, the structures of the rotating shearing disc 4 and the fixed shearing disc 6 were specially designed, specifically as follows:

[0094] The gap decreases gradually: The axial width (i.e., vertical spacing) and radial width (i.e., inner and outer spacing) of the grinding gap are both set to decrease gradually from the innermost layer (near the center) to the outermost layer (near the edge), which makes the shearing action on the material as it flows from the inner layer to the outer layer increasingly fine.

[0095] The shearing grooves change gradually: from the innermost layer to the outermost layer, the number of the first shearing groove 8 and the second shearing groove 9 increases layer by layer, while the width of a single groove decreases layer by layer. The increase in the number means that the material is sheared more times per unit time, and the decrease in width means that the shearing action is more concentrated and more precise.

[0096] The "no-edge" design of the first shear groove 8: This is the key to ensuring no dead corners and forcing materials to pass through the grinding gap. Except for the innermost layer, the first shear groove 8 of each other layer is designed as a "two-sided open" structure, that is, the top (axial) and outer peripheral (radial) sides of the raised layer in which it is located are open, but there is a gap between the radial inner end (i.e. the end facing the rotation center) and the outer wall of the adjacent inner raised layer.

[0097] Meanwhile, the axial bottom end of the first shear groove 8 does not extend to the bottom surface of the protrusion layer.

[0098] In other words, the axial depth of the first shear groove 8 in each layer is less than the protrusion height of the protrusion layer in which it is located; except for the innermost layer, the length of the first shear groove 8 in the other layers measured on the horizontal plane along a straight line pointing to the axis of rotation (i.e., its radial projection dimension) is less than the radius difference between the protrusion layer in which it is located and the inner adjacent protrusion layer.

[0099] The "no edge" design of the second shear groove 9: The design of the second shear groove 9 corresponds to the first shear groove 8, but the spatial position is mirror symmetrical.

[0100] Except for the outermost layer, the second shear groove 9 of each of the other layers is designed as an "open on both sides" structure, that is, the bottom (axial) and inner circumferential (radial) side of the recessed layer in which it is located are open, but the radially outer end (i.e. the end away from the rotation center) is separated from the inner wall of the adjacent outer recessed layer.

[0101] Meanwhile, the axial top end of the second shear groove 9 does not extend to the top surface of the recessed layer.

[0102] In other words, the axial depth of the second shear groove 9 in each layer is less than the depth of the depression layer in which it is located; except for the outermost layer, the radial depth of the second shear groove 9 in the remaining layers is less than the radius difference between the depression layer in which it is located and the adjacent depression layer.

[0103] The outermost second shear groove 9 has a special design: the width of the outermost second shear groove 9 is set to be smaller than the minimum particle size of the grinding media used in the subsequent media grinding. In this embodiment, the width of the outermost second shear groove 9 is less than 3.0 mm. This design can effectively prevent the grinding media from entering the upper shearing and grinding area, ensuring that the two-stage grinding functions are both coordinated and do not interfere with each other.

[0104] This symmetrical design of the shear grooves, which do not reach the edges, ensures that materials cannot be "short-circuited" between the shear grooves of adjacent layers. Instead, they are forced to pass through the "main grinding zone," which has the strongest shearing effect, formed by the gap between the rotating shear plate 4 and the fixed shear plate 6. This achieves multi-directional, dead-angle-free, step-by-step rigid shearing and grinding of the materials.

[0105] To optimize feeding and initial material flow, a stepped hole 10 is provided at the top center of the rotary shearing disc 4. This stepped hole 10 is used to securely mount the rotary shearing disc 4 onto the rotary shaft 3 with bolts and keys, and its sidewall is connected to the innermost first shearing groove 8.

[0106] The first shearing groove 8 is designed with an inclined structure. When it rotates with the rotating shearing disk 4, the inclined groove wall will apply a centrifugal force component to the material, thereby more effectively throwing the material from the central stepped hole 10 to the grinding gap, which can improve the grinding efficiency and also allow the material to flow to the next grinding layer.

[0107] The material falls into the feed hole 12 of the fixed shearing disc 6 and directly enters the space formed by the innermost first shearing groove 8 and the second shearing groove 9 to start the first stage of shearing.

[0108] Throughout the process, the equipment relies on the centrifugal force generated by rotation to transport materials, eliminating the need for an external material conveying pump and enabling direct material intake, thus simplifying the system.

[0109] After undergoing multi-stage shearing and grinding, the material is thrown out from the outermost grinding gap and enters the annular casing 5.

[0110] The internal space of the annular housing 5 forms a grinding chamber, which is filled with a certain amount of grinding media. The grinding media includes grinding balls of different particle sizes mixed in a certain proportion. In this embodiment, the grinding media is: grinding balls Y1 with a particle size of 3.0 to 3.2 mm account for 30%, grinding balls Y2 with a particle size of 3.2 to 3.4 mm account for 30%, and grinding balls Y3 with a particle size of 3.4 to 3.6 mm account for 40%. In this embodiment, the total filling amount of grinding media is 5 kg.

[0111] In order to perform media grinding on the material, several agitator discs 7 are fixedly installed on the part of the rotating shaft 3 located inside the annular housing 5.

[0112] Specifically, the stirring disc 7 is fixed on the rotating shaft 3 by a sleeve. Three stirring discs 7 are distributed from top to bottom. There is a gap between two adjacent stirring discs 7. Several stirring holes are opened on the stirring disc 7. Some stirring discs 7 are also provided with protrusions.

[0113] When the rotating shaft 3 drives the agitator 7 to rotate, they will violently agitate the grinding media, causing collisions, compression and friction between the media and between the media and the material, thereby further grinding the material.

[0114] To prevent the grinding media from entering the upper shearing and grinding zone, the width of the second shear groove 9 in the outermost layer (i.e., the bottommost layer) is set to be smaller than the minimum particle size of all grinding balls (i.e., less than 3.0 mm).

[0115] The equipment is equipped with a filtration system to separate the grinding media from the qualified slurry produced after grinding.

[0116] The filter assembly includes a cylindrical filter element 11, which is fixed to the inner wall of the annular housing 5 by a static seal, and an annular flow channel is formed between the cylindrical filter element 11 and the inner wall of the annular housing 5.

[0117] On the side wall of the annular housing 5, there is a discharge hole that communicates with the annular flow channel and is connected to a discharge pipe head.

[0118] The ground slurry passes through the cylindrical filter element (11) under pressure, and then enters the annular flow channel between the cylindrical filter element (11) and the inner wall of the annular housing (5), and is finally discharged through the discharge hole and the discharge pipe connected thereto.

[0119] The pore size of the cylindrical filter element (11) is smaller than the particle size of the grinding media, so the grinding media is blocked in the grinding chamber.

[0120] For ease of cleaning and maintenance, a backflow drain hole can be provided on the outer wall of the annular housing 5, which is normally sealed with a plug.

[0121] Because the grinding process generates heat, this equipment also integrates a cooling system.

[0122] An inner cylinder 13 is fixed to the inner wall of the annular housing 5 by static sealing. The interlayer space between the inner cylinder 13 and the inner wall of the annular housing 5 forms a cooling chamber. A water inlet and a water outlet communicating with this cooling chamber are provided on the annular housing 5.

[0123] To enhance the cooling effect, a spiral baffle is welded into the cooling chamber, so that the cooling water enters from the inlet hole, flows through the entire chamber along the spiral path, and then flows out from the outlet hole, achieving uniform and efficient cooling of the grinding area.

[0124] A dynamic sealing component is installed at the point where the rotating shaft 3 passes through the bottom of the annular housing 5 to prevent slurry leakage. The housing fixed on the frame 1 provides protection and support for the entire equipment.

[0125] The working principle of this embodiment is as follows:

[0126] Before use, feed the slurry material to be ground through the feed pipe.

[0127] When in operation, start motor 2, which drives rotating shaft 3, rotating shearing disk 4 and stirring disk 7 to rotate together.

[0128] Material is continuously fed in through the feed hole 12 and falls into the stepped hole 10 area in the center of the rotating shearing disk 4. Under the action of centrifugal force, it is thrown into the multi-layer stepped shearing and grinding zone composed of the rotating shearing disk 4 and the fixed shearing disk 6.

[0129] The material flows sequentially from the inner layer to the outer layer, undergoing "rigid shearing and grinding" with gradually decreasing gaps and progressively increasing shearing force, thus being effectively crushed, especially efficient in handling high-hardness impurities.

[0130] After initial crushing, the material enters the grinding chamber of the annular casing 5. Driven by the stirring disc 7, it mixes with the grinding media and undergoes further "media grinding" to achieve the target fineness.

[0131] The slurry of the required fineness passes through the cylindrical filter element 11 and is discharged from the discharge hole through the annular flow channel, while the grinding media is retained by the filter element.

[0132] The cooling system operates continuously, removing the heat generated during grinding.

[0133] The entire process is completed continuously in one machine, realizing the integration from pre-shearing to fine grinding, and has the advantages of high efficiency, low energy consumption, small footprint, and uniform product particle size.

[0134] Application Example 1: Grinding of sulfonylurea technical material suspension.

[0135] This pre-grinding equipment has been validated in the production of sulfonylurea technical suspension.

[0136] The original process used three 100-liter sand mills connected in series. Because the raw material contained crystal particles with extremely high hardness, it had to be circulated and ground twice (total time was about 8 hours) to barely achieve a product fineness D90 of 3.0µm, with a wide particle size distribution and a sieve pass rate of 92%.

[0137] After using the equipment of this invention (model HR-55YM) as a pre-processor, the process is optimized to "1 pre-grinding mill + 2 100-liter sand mills" connected in series. The pre-grinding mill utilizes its multi-layer stepped shear structure to effectively crush the high-hardness crystals in advance.

[0138] After optimization, the material only needs to pass through the subsequent two sand mills once to complete the grinding, reducing the production time per batch to 4.5 hours and improving efficiency by about 44%.

[0139] The fineness of the product has been significantly improved, with a fineness D90 of 1.8µm and a narrower particle size distribution. The sieve passing rate reaches 100%, and there is no crystal residue.

[0140] At the same time, the equipment investment was reduced by 1 unit (a reduction of about 33%), the energy consumption per ton of product decreased from 120kWh to 85kWh (a reduction of about 29%), and the required number of operators was reduced from 2 to 1.

[0141] The specific verification process is as follows:

[0142] Experimental product: Sulfonylurea technical suspension.

[0143] Original process configuration: 3 100-liter sand mills in series for grinding.

[0144] Key pain point: Because the raw material contains extremely hard crystalline particles, conventional grinding methods are difficult to break them in one go.

[0145] Original process: It required two rounds of grinding to barely meet the standards, resulting in severe equipment wear and extremely long production cycles.

[0146] Experimental equipment: Pre-grinding mill (model: HR-55YM).

[0147] Control group:

[0148] Control group (without using a pre-grinding machine): 3 100-liter sand mills, running at full power, cyclically grinding twice.

[0149] Experimental group (using a pre-grinding machine): 2 x 100L sand mills + pre-grinding machine, single grinding pass.

[0150] Comparison of core experimental data, such as Figure 8 As shown.

[0151] In-depth analysis of experimental data:

[0152] Efficiency: Capacity release is 44%. Without the pre-grinding mill, three sand mills must run at full load for eight hours to complete one batch. After the introduction of the pre-grinding mill, the hard crystals are pre-crushed, so that the subsequent two sand mills only need to grind once to meet the standard.

[0153] Result: The production time per batch was reduced from 8 hours to 4.5 hours, and the overall production capacity was increased by nearly half.

[0154] Significant cost reduction: Overall costs decreased by approximately 30%.

[0155] Equipment wear: The number of grinding passes is reduced from 2 to 1, and the wear of the grinding media and lining inside the sand mill is directly halved.

[0156] Energy consumption data: Data shows that due to the shortened process and reduced equipment, the power consumption per ton of product has decreased from 120kWh to 85kWh, a reduction of 29%.

[0157] Human resource optimization: What used to require two people to take turns operating three machines can now be done by just one person, reducing labor costs by about 54%.

[0158] Quality change: Particle size distribution narrowed by approximately 44%.

[0159] Key finding: The unique shearing design of the pre-grinding mill ensures more uniform pretreatment of hard crystals, avoiding the phenomenon of insufficient grinding in sand mills.

[0160] Data supports this: the product's fineness D90 value has decreased from 3.0µm to 1.8µm, and the particle size distribution range has narrowed by about 40%. This means that the product has a higher suspension rate, better stability, and no risk of secondary precipitation.

[0161] Application Example 2: Grinding of various pesticide suspensions.

[0162] In the production of suspensions such as 40% pyraclostrobin and 24% pyrazole, this pre-grinding equipment also demonstrated significant optimization effects.

[0163] Taking 40% pyrazole tebuconazole suspension as an example, the original process required 5 sand mills connected in series and circulated grinding for 4.2 hours to achieve a product fineness D90≤3µm.

[0164] After introducing the pre-grinding machine of this invention for precision pre-shearing, only 3 sand mills need to be started to maintain a production capacity of 700 kg / h while ensuring that the product achieves the same fineness index. The system pressure is stable and there is no overload or overpressure phenomenon.

[0165] This optimization reduces the number of units by 2, improves overall efficiency by about 40%, reduces power consumption per ton by about 40%, and reduces the cost of related auxiliary materials (refrigerant, zirconium beads) by about 45%.

[0166] For 24% pyrazole suspension (liquid), the original process required 5 units to operate at full load. After optimization, only 2 sand mills are needed in series. The product fineness D90≤2.9µm is achieved, and the efficiency is comparable to that of 5 units. This achieves the effect of reducing 3 units and increasing the overall efficiency by 60%.

[0167] When processing 24% pyrazole suspension powder raw material (pyrazole powder), the original process required one sand mill for coarse grinding, followed by two sand mills in series for grinding, with a capacity of 680 kg / h and a product fineness D90≤4µm. After pre-treatment with the pre-grinding machine of this invention, only one sand mill is used for the entire process. Under the same capacity, the product fineness is improved to D90≤3.5µm, successfully reducing two units and improving the overall efficiency by about 40%.

[0168] The specific verification process is as follows:

[0169] Product 1: 40% pyrazole tebuconazole suspension.

[0170] Conventional process: 5 sand mill units (No. 1-5) are used in series, with a total capacity of 700 kg / h. The product fineness D90≤3μm requires 4.2 hours of circulating grinding.

[0171] Process optimization: Through fine shearing with a pre-grinding mill, only units 2-4 (3 units) are used, the total capacity is maintained at 700kg / h, the product fineness D90≤3μm (same particle size), and the number of cycles is reduced by 2 machines.

[0172] Key findings: The axial flow design of the precision pre-grinding mill makes material crushing more uniform and avoids single-unit pressure overload and overpressure (the system pressure is stable and no overpressure phenomenon has occurred).

[0173] Conclusion: Reducing the number of generating units by two resulted in a 40% increase in overall efficiency.

[0174] Product 2: 24% pyrazole suspension.

[0175] Conventional process: 5 sand mill units operate at full load, with a total capacity of 1100 kg / h and a product fineness D90≤3μm.

[0176] Optimized process: Using a pre-grinding mill for shearing, and with the same grinding flow rate, only two sand mill units (No. 4 and No. 5) are connected in series. Through testing, the product fineness D90 ≤ 2.9μm is achieved, which is almost the same as the efficiency of five machines.

[0177] Key findings: The axial flow design of the pre-grinding mill makes material crushing more uniform and avoids single-unit pressure overload (system pressure is stable and no overpressure phenomenon has occurred).

[0178] Conclusion: Reducing the number of generating units by 3 resulted in a 60% increase in overall efficiency.

[0179] Product 3: 24% pyrazole suspension (pyrazole powder).

[0180] Conventional process: First, coarse grinding is performed using No. 1 sand mill. After the formula is obtained, No. 1 and No. 2 mills are used for joint grinding, with a capacity of 680 kg / h and a product fineness D90≤4μm.

[0181] Optimized process: Pre-treatment with a pre-grinding machine is adopted, and the No. 2 machine is used for full-process processing. Under the same processing capacity, the product fineness D90 ≤ 3.5μm.

[0182] Key findings: The axial flow design of the precision shearing machine makes material crushing more uniform and avoids single-unit pressure overload (the system pressure is stable and no overpressure phenomenon has occurred).

[0183] Conclusion: Reducing the number of generating units by two resulted in a 40% increase in overall efficiency.

[0184] Comparison of experimental data, such as Figure 9 As shown.

[0185] These practical applications demonstrate that the pre-grinding equipment of the present invention, through its efficient shearing and crushing capabilities, can serve as a core pre-treatment unit, significantly simplifying the subsequent grinding process and achieving cost reduction and efficiency improvement.

[0186] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pre-grinding device, comprising a frame (1), characterized in that: A grinding assembly is installed on the frame (1), and a filter assembly is provided inside the grinding assembly; The grinding assembly includes a motor (2), and a rotating shaft (3) is fixed to the output shaft end of the motor (2). A rotating shearing disk (4) is fixed on the top outer periphery of the rotating shaft (3). An annular housing (5) is fixed to the upper side of the motor (2), and a fixed shearing disc (6) is fixed to the top of the annular housing (5). Several agitator discs (7) are fixed on the outer periphery of the rotating shaft (3). The fixed shearing disc (6) includes a feed hole (12) at its top, and the fixed shearing disc (6) is located above the rotating shearing disc (4) and the two are arranged opposite to each other. The top of the rotating shearing disk (4) is a multi-layered stepped disk-shaped protrusion structure that increases in height from the outside to the inside, and the bottom of the fixed shearing disk (6) is a multi-layered stepped disk-shaped concave structure that deepens in depth from the outside to the inside. The protrusions of the rotating shearing disk (4) and the concave layers of the fixed shearing disk (6) are spaced apart in both the axial and radial directions, thereby forming a grinding gap between the layers. The rotating shearing disk (4) has several first shearing grooves (8) arranged circumferentially on the outer wall of each layer of the protrusion. The fixed shearing disc (6) has several second shearing grooves (9) arranged circumferentially on the inner wall of each layer of the recess. The axial and radial widths of the grinding gap decrease layer by layer from the inner layer to the outer layer; From the inner layer to the outer layer, the number of the first shear groove (8) and the second shear groove (9) increases layer by layer and the width decreases layer by layer; The axial depth of the first shear groove (8) in each layer is less than the protrusion height of the protrusion layer in which it is located; Except for the innermost layer, the length of the first shear groove (8) in each of the other layers, measured on the horizontal plane along a straight line pointing to the axis of rotation, is less than the radius difference between the protruding layer in which it is located and the adjacent inner protruding layer. The axial depth of the second shear groove (9) in each layer is less than the depth of the depression in the depression layer in which it is located; Except for the outermost layer, the radial depth of the second shear groove (9) in each of the remaining layers is less than the radius difference between the recessed layer in which it is located and the adjacent outer recessed layer.

2. The pre-grinding equipment according to claim 1, characterized in that: When the rotating shearing disc (4) rotates, it cooperates with the fixed shearing disc (6) to perform multi-directional, dead-angle-free, step-by-step rigid shearing and grinding on the material.

3. The pre-grinding equipment according to claim 1, characterized in that: The rotating shearing disk (4) has a stepped hole (10) at the top center, and the innermost first shearing groove (8) is connected to the stepped hole (10). The first shear groove (8) is an inclined structure.

4. The pre-grinding equipment according to any one of claims 2 to 3, characterized in that: The annular housing (5) is filled with grinding media, which grinds the material after shearing and grinding by cooperating with the grinding media when the agitator (7) rotates.

5. The pre-grinding equipment according to claim 4, characterized in that: The grinding media is confined within the annular housing (5) by the filter assembly, and the ground material is discharged through the filter assembly. The filter assembly includes a cylindrical filter element (11) fixed to the inner wall of the annular housing (5), and an annular flow channel is formed between the cylindrical filter element (11) and the inner wall of the annular housing (5). The side wall of the annular housing (5) is provided with a discharge hole that communicates with the annular flow channel.

6. The pre-grinding equipment according to claim 1, characterized in that: An inner cylinder (13) is also fixed on the inner wall of the annular housing (5). A cooling chamber is formed between the inner cylinder (13) and the inner wall of the annular housing (5). The annular housing (5) is provided with an inlet hole and an outlet hole that communicate with the cooling chamber. A spiral baffle is provided inside the cooling chamber.

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