Fertilizer screening device

Abstract

The invention belongs to the technical field of fertilizer processing equipment, and provides a fertilizer screening device which comprises a main body rack, a screening machine cover is fixedly arranged at the upper end of the main body rack, a feeding cylinder is fixedly arranged at one end of the screening machine cover, a feeding opening is formed in the feeding cylinder, and a hopper is installed at the feeding opening through a flange plate; a screening barrel connected with an outlet of the feeding barrel is arranged in the screening machine cover, and a fertilizer conveying and feeding drive is installed at the end, away from the screening machine cover, of the feeding barrel; the main body rack is provided with a plurality of discharging funnels for independently discharging the sieved fertilizer; a machine cover end cover is fixedly arranged on the side, away from the feeding cylinder, of the screening machine cover. By integrating the material dispersing and multi-stage screening structure, online material dispersing and grading screening of fertilizer particles are achieved, and the technical problems that traditional split type equipment is low in space utilization rate, unstable in material dispersing efficiency and insufficient in screening precision are effectively solved.

Description

Technical Field

[0001] This invention belongs to the technical field of fertilizer processing equipment, specifically a fertilizer screening device. Background Technology

[0002] Blended fertilizer (BB fertilizer) is a multi-nutrient fertilizer made by physically mixing different single-element fertilizers or compound fertilizers. Its production process is flexible and efficient. In the production of blended fertilizer, it is necessary to select single-element nitrogen, phosphorus, and potassium fertilizers or compound fertilizers with similar particle sizes to avoid separation. After being weighed by an automatic metering device, they are transported to a horizontal mixer for cyclic mixing to ensure uniformity. The mixed fertilizer is then processed by a screening machine; large particles are broken up and returned to the mixing process. The finished product is sealed by an automatic packaging machine. However, existing methods require a conveyor belt and a material dispersing mechanism at the tail of the screening machine. The conveyor belt transports oversized fertilizer particles discharged from the tail of the screening machine to the material dispersing mechanism for breaking them up, extending the length of the production line, occupying a large amount of space, and increasing fertilizer loss during processing.

[0003] Patent application number 202310595006.7 discloses a fertilizer screening system. This system efficiently screens granulated fertilizer particles and directly crushes oversized particles inside the equipment before returning them to a disc granulator for regranulation. This design significantly shortens the production line length, saves valuable production space, and effectively reduces material losses during conveying and independent crushing processes, offering significant advantages in improving overall production efficiency and reducing operating costs.

[0004] However, in this specific application scenario, a prominent technical problem is that due to the diversity of blended fertilizer formulations, batch differences in raw materials, and fluctuations in granulation process parameters, oversized fertilizer particles entering the screening system exhibit significant differences in physical properties, particularly in hardness, density, and moisture content. Existing integrated material dispersing mechanisms, while achieving efficient material dispersing through the counter-rotation of the screen drum and baffle plate, and the presence of dispersing teeth one and two, typically operate their drive motors at a fixed speed. This results in a constant relative speed of movement for the dispersing teeth and the resulting impact, shearing, or crushing forces. This fixed-parameter dispersing method may lead to incomplete dispersing, low efficiency, and even increased wear on the dispersing teeth and equipment blockage when dealing with harder particles. Furthermore, fertilizer agglomeration is equivalent to large-particle fertilizer, requiring further dispersing and re-screening.

[0005] In addition, in the aforementioned patent, fertilizer screening is achieved using only a single screen roller, which cannot achieve a good screening effect. Summary of the Invention

[0006] The purpose of this invention is to provide a fertilizer screening device that solves the technical problems of low space utilization, unstable material dispersing efficiency, and insufficient screening accuracy of traditional split-type equipment.

[0007] The technical solution adopted by this invention to solve its technical problem is as follows: a fertilizer screening device, comprising a main frame, a screening cover fixedly installed on the upper end of the main frame, a feed cylinder fixedly installed at one end of the screening cover, a feeding port provided on the feed cylinder, and a hopper installed at the feeding port via a flange; a screening cylinder connected to the outlet of the feed cylinder is provided inside the screening cover, and a drive for conveying and feeding fertilizer is installed at the end of the feed cylinder away from the screening cover; multiple discharge funnels for independently discharging the screened fertilizer are provided on the main frame; a cover end cap is fixedly installed on the side of the screening cover away from the feed cylinder, and a dispersing mechanism for dispersing fertilizer is installed on the cover end cap; a screening frame is provided on the lower inner side of the screening cover, and the screening frame is located between the discharge funnels and the screening cylinder for further screening the fertilizer screened in the screening cylinder.

[0008] Preferably, the feeding drive includes a feeding motor fixedly installed on the feeding cylinder, the output end of the feeding motor is fixedly connected to a feeding shaft, the feeding shaft passes through the feeding cylinder and the screening cylinder, and feeding spiral blades for spirally pushing fertilizer are fixedly arranged on the outer periphery of the feeding shaft inside the feeding cylinder and the screening cylinder. Multiple linkage support rods arranged in a ring array are provided at the outlet of the feeding shaft of the feeding cylinder, and the linkage support rods are fixedly connected to the screening cylinder for synchronously driving the screening cylinder to rotate.

[0009] Preferably, the screening cylinder includes a screen drum, the side wall of which is evenly provided with a plurality of screening holes, both ends of which are rotatably connected to the inner wall of the screening machine cover through a cylinder bearing seat, and the cylinder bearing seat is fixedly installed inside the screening machine cover by a bearing bracket, and the side of the screen drum away from the feed cylinder is provided with a plurality of material dispersing teeth that cooperate with the material dispersing mechanism.

[0010] Preferably, the bulk material dispersing mechanism includes a motor bracket fixedly mounted on the end cover of the machine hood, a bulk material dispersing motor fixedly mounted on the motor bracket, the output shaft of the bulk material dispersing motor passing through the end cover of the machine hood and fixedly connected to a bulk material sleeve, a plurality of bulk material teeth two cooperating with the first bulk material teeth to disperse fertilizer are fixedly provided on the outer periphery of the bulk material sleeve, and a plurality of pushing blades arranged in a circular array are fixedly provided on the bulk material sleeve, the pushing blades being used to push fertilizer particles to the bulk material teeth; the lower part of the screening machine hood, located below the bulk material sleeve, is provided with a discharge trough for discharging the dispersed fertilizer.

[0011] Preferably, a cleaning brush for cleaning the bulk material motor and the bulk material teeth is fixedly installed on the top inner side of the screening machine cover.

[0012] Preferably, the bulk material motor is a variable frequency motor equipped with a frequency converter, and a high-precision current sensor is installed on the power line of the bulk material motor to monitor the operating current of the motor in real time; an industrial-grade programmable logic controller or a dedicated industrial controller is set on the main frame, which interacts with the frequency converter and the current sensor to adjust the speed of the bulk material motor according to the type of fertilizer.

[0013] Preferably, the method by which the controller adjusts the speed of the bulk material motor according to the type of fertilizer is as follows: After the fertilizer is fed into the feed cylinder, the feeding motor starts at a preset reference speed under the initial command of the controller, driving the screen drum and the feeding shaft to rotate for preliminary screening. When oversized fertilizer particles are pushed between the first and second dispersing teeth by the feeding screw, the current sensor will monitor the load current of the dispersing motor in real time; the magnitude of the load current directly reflects the resistance borne by the dispersing, that is, the hardness of the dispersing particles or the difficulty of dispersing. If the controller detects that the load current is consistently higher than the preset hard particle threshold, it indicates that it is processing harder particles or that the resistance of the bulk material is increasing. The controller will immediately send a command to the frequency converter to gradually increase the speed of the bulk material motor. The increase in the speed of the bulk material motor will simultaneously increase the reverse speed of the cylinder bearing seat and the bulk material sleeve, thereby increasing the relative speed between the first and second bulk material teeth and the impact, shearing or crushing force, ensuring that hard particles can be dispersed efficiently and thoroughly. If the controller detects that the load current is consistently lower than the preset soft particle threshold, it indicates that softer particles are being processed or the resistance of the bulk material is decreasing. The controller will send a command to the frequency converter to gradually reduce the speed of the bulk material motor. The reduction in motor speed will reduce the relative speed and force of the bulk material teeth, effectively avoiding over-crushing of soft particles, thereby reducing the generation of fine dust and material loss.

[0014] Preferably, the screening frame includes a receiving tray disposed inside the screening machine cover. A screen is detachably installed on the inner side of the receiving tray. The screen is installed at an angle inside the receiving tray, with the side closer to the feed cylinder higher than the side farther from the feed cylinder. The screen is provided with a plurality of screen holes, and the screen holes on the side closer to the feed cylinder are smaller than the screen holes on the side farther from the feed cylinder.

[0015] Preferably, the screening frame further includes two sets of limiting guide rails fixedly installed on the inner wall of the screening machine cover. Limiting sliders are slidably connected to the limiting guide rails, and the limiting sliders are fixedly connected to the outer wall of the receiving tray. Multiple vibration springs are fixedly installed on the side wall of the receiving tray near the feed cylinder. The side of the vibration springs away from the receiving tray is fixedly connected to the inner wall of the screening machine cover. The elasticity of the vibration springs drives the receiving tray to slide back and forth along the limiting guide rails to vibrate and screen the fertilizer.

[0016] Preferably, a linkage wedge is fixedly provided on the upper end of the receiving tray near the feeding cylinder, and a drive disk is fixedly provided on the outer periphery of the screen roller. The drive disk has multiple drive wedge grooves arranged in a ring array on the end face near the receiving tray. The drive wedge grooves are wedge-shaped and engage with the linkage wedge. When the drive disk rotates, the pressing action of the linkage wedge and the drive disk drives the receiving tray to slide back and forth along the limiting guide rail, and it is rebounded and reset by the elastic action of the vibration spring.

[0017] The beneficial effects of this invention are as follows: By integrating the bulk material mechanism with the multi-stage screening structure, online bulk material distribution and grading screening of fertilizer particles are realized. The intelligent adjustment mechanism of frequency conversion control combined with current feedback is used to optimize the bulk material parameters. With the linkage-driven vibrating screening design, the technical problems of low space utilization, unstable bulk material efficiency and insufficient screening accuracy of traditional split equipment are effectively solved. It has the technical effects of high equipment integration, excellent energy consumption utilization and controllable screening particle size. Attached Figure Description

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] Figure 1 This is a three-dimensional structural diagram of the entire invention; Figure 2 This is a schematic diagram of the overall axonometric structure of the present invention; Figure 3 This is a cross-sectional view of the overall structure of the present invention; Figure 4 This is the present invention. Figure 3 Enlarged structural diagram at point A; Figure 5 This is a schematic diagram of the feeding shaft of the present invention; Figure 6 This is a schematic diagram of the assembly structure of the screening cylinder and screening frame of the present invention; Figure 7 This is a three-dimensional structural schematic diagram of the screening cylinder of the present invention; Figure 8 This is a schematic diagram of the axial structure of the screening cylinder of the present invention; Figure 9 This is a three-dimensional structural diagram of the screening rack of the present invention.

[0020] In the diagram: 1. Main frame; 2. Screening machine cover; 3. Feed cylinder; 4. Feeding drive; 41. Feeding motor; 42. Feeding shaft; 43. Feeding spiral blade; 44. Linkage support rod; 5. Machine cover end cap; 6. Bulk material mechanism; 61. Motor bracket; 62. Bulk material motor; 63. Bulk material cover; 64. Pushing blade; 65. Bulk material tooth two; 7. Discharge hopper; 8. Screening cylinder; 81. Screen drum; 82. Cylinder bearing seat; 83. Bearing bracket; 84. Bulk material tooth one; 85. Drive disc; 86. Drive wedge groove; 9. Screening frame; 91. Receiving tray; 92. Screen; 93. Limiting guide rail; 94. Limiting slider; 95. Linkage wedge block; 96. Vibration spring; 10. Outlet groove; 11. Cleaning brush. Detailed Implementation

[0021] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0022] Please see Figures 1-9 As shown in the embodiment of this application, a fertilizer screening device is proposed, including a main frame 1, a screening cover 2 fixedly installed on the upper end of the main frame 1, a feed cylinder 3 fixedly installed at one end of the screening cover 2, a feeding port provided on the feed cylinder 3, and a hopper installed at the feeding port through a flange; a screening cylinder 8 connected to the outlet of the feed cylinder 3 is provided inside the screening cover 2, and a fertilizer conveying drive 4 is installed at the end of the feed cylinder 3 away from the screening cover 2; multiple discharge funnels 7 are provided on the main frame 1 for independent discharge of the screened fertilizer; a cover end cap 5 is fixedly installed on the side of the screening cover 2 away from the feed cylinder 3, and a dispersing mechanism 6 for dispersing fertilizer is installed on the cover end cap 5; a screening frame 9 is provided on the lower inner side of the screening cover 2, and the screening frame 9 is located between the discharge funnels 7 and the screening cylinder 8 for further screening the fertilizer screened in the screening cylinder 8.

[0023] The main frame 1 serves as the structural foundation of the entire device. It can be constructed using a metal frame structure, such as welded or bolted steel, to support the various functional modules and ensure overall stability. The screening machine hood 2 forms a closed working space. It can be machined from steel plates and connected to other components via sealing strips or sealant to prevent dust diffusion. The flange connection between the feed cylinder 3 and the hopper can use standard flanges and bolts for easy disassembly and maintenance. The feeding drive 4 can be implemented using mechanical transmission methods such as belt drive, chain drive, or gear drive to rotate the screening cylinder 8 and complete the initial screening. The number and arrangement of the discharge funnels 7 can be adjusted according to actual needs, for example, by setting two or three to collect materials of different particle sizes.

[0024] Furthermore, the bulk material handling mechanism 6 integrated into the end cover 5 can be implemented in various ways, such as using hammer milling, roller milling, or shear milling, to meet the immediate processing needs of oversized particles. The screening frame 9 can be designed with a multi-layer screen structure or a vibrating screen structure, with specific implementation methods including but not limited to electromagnetic vibration, eccentric wheel vibration, or pneumatic vibration, thereby improving screening accuracy. The choice of these implementation methods mainly depends on the specific process requirements and material characteristics.

[0025] The innovation of this application lies in constructing an internal material circulation processing system by integrating a bulk material handling mechanism with a secondary screening function. Compared to existing technologies that require a conveyor belt and bulk material handling machine at the tail of the screening machine, this design significantly shortens the production line length and reduces space occupation. Simultaneously, by directly installing the bulk material handling mechanism 6 inside the screening machine cover 2, the problem of large, agglomerated particles requiring external transport and rework is avoided, reducing material loss during transport. Furthermore, the secondary screening design of the screening frame 9 further improves screening accuracy, forming a complete closed-loop material handling system and solving the space waste problem caused by the back-and-forth material transport in traditional processes.

[0026] The working principle of this embodiment is as follows: The main frame 1 serves as the structural foundation of the entire device, supporting and fixing each functional module. The screening machine hood 2 forms an independent working space through its enclosed design, effectively preventing dust diffusion and protecting the internal components. The feed cylinder 3 and the hopper are quickly connected via a flange, facilitating feeding operations while ensuring the sealing of the connection. The feeding drive 4 drives the screening cylinder 8 to rotate, causing the fertilizer to undergo initial screening within the screening cylinder 8. Larger particles are intercepted, while smaller particles pass through the screening holes to enter the next stage.

[0027] Furthermore, the material dispersing mechanism 6 installed on the end cover 5 directly disperses oversized particles intercepted by the screening cylinder 8, eliminating the need for additional conveying equipment, thus significantly shortening the process flow and reducing material loss. The screening frame 9, positioned between the discharge funnel 7 and the screening cylinder 8, performs secondary screening of the received initial screening product to improve overall screening accuracy. The design of the screening frame 9 allows for more thorough material grading, ensuring accurate separation of fertilizers of different particle sizes and independent collection through multiple discharge funnels 7.

[0028] Therefore, this technical solution integrates a bulk material handling mechanism with a secondary screening function to construct a complete internal material circulation system. Specifically, the material processed by the bulk material handling mechanism 6 re-enters the screening process, and the screening rack 9 further classifies the products from the initial screening, forming a closed-loop processing mechanism. This synergistic effect not only solves the space waste problem caused by the back-and-forth material transport in traditional processes, but also reduces material loss through real-time bulk material handling, while improving the adaptability to particles of different hardness, and avoiding inefficiency and equipment wear risks caused by incomplete bulk material handling or over-crushing.

[0029] Please see Figures 1-5 As shown, this application further proposes a feeding drive 4 including a feeding motor 41 fixedly installed on the feeding cylinder 3. The output end of the feeding motor 41 is fixedly connected to a feeding shaft 42. The feeding shaft 42 passes through the feeding cylinder 3 and the screening cylinder 8. Feeding spiral blades 43 for spirally pushing fertilizer are fixedly provided on the outer periphery of the feeding shaft 42 inside the feeding cylinder 3 and the screening cylinder 8. Multiple linkage support rods 44 arranged in a ring array are provided at the outlet of the feeding shaft 42. The linkage support rods 44 are fixedly connected to the screening cylinder 8 for synchronously driving the screening cylinder 8 to rotate.

[0030] Specifically, the feeding motor 41 refers to a drive device capable of providing stable power output, which can be implemented using an AC asynchronous motor, a DC brushless motor, or a servo motor. In practical applications, the feeding shaft 42 is a rigid transmission shaft, and its material can be high-strength alloy steel or stainless steel to ensure structural stability under high torque conditions. The feeding spiral blade 43 is a key component for material conveying through a continuous spiral surface structure, and it can be manufactured through cold rolling or machining. The linkage rod 44 is a connecting component that transmits torque; its annular array distribution is designed to evenly distribute the transmission load and reduce stress concentration.

[0031] In detail, this solution directly connects the feeding motor 41 to the feeding shaft 42, utilizing a through-type structure to achieve synchronous control of fertilizer conveying and the rotation of the screening cylinder 8. The feeding spiral blades 43 on the outer periphery of the feeding shaft 42 generate axial thrust during fertilizer conveying, ensuring uniform material flow and preventing blockages caused by accumulation. The linkage rod 44 directly transmits the rotational motion of the feeding shaft 42 to the screening cylinder 8, achieving dynamic matching between the rotational speed of the screening cylinder 8 and the feeding speed, effectively solving the problem of material retention caused by inconsistent rotational speeds. This mechanical linkage method not only simplifies the power system structure but also improves the reliability of equipment operation through uniform torque transmission. Furthermore, the continuous pushing action of the feeding spiral blades 43 combined with the synchronous drive of the linkage rod 44 forms a highly efficient material conveying and screening system, significantly improving overall work efficiency.

[0032] Please see Figures 6-8As shown, this application further proposes that the screening cylinder 8 includes a screen roller 81, the side wall of which is evenly provided with a plurality of screening holes, both ends of which are rotatably connected to the inner wall of the screening machine cover 2 through a cylinder bearing seat 82, and the cylinder bearing seat 82 is fixedly installed inside the screening machine cover 2 through a bearing bracket 83, and a plurality of material dispersing teeth 84 that cooperate with the material dispersing mechanism 6 are provided on the side of the screen roller 81 away from the feed cylinder 3.

[0033] Specifically, the screen drum 81 is a cylindrical component with a porous structure, which can be made of stainless steel to ensure wear resistance and corrosion resistance, and its purpose is to achieve dynamic screening of materials. The screening holes are a key structure used for grading according to particle size, and their diameter can be flexibly adjusted according to actual needs. The cylinder bearing seat 82 can be understood as a support and positioning device, which can be implemented using rolling bearings or sliding bearings, to ensure the smooth rotation of the screen drum 81. The bearing bracket 83 is a fixed support structure, which can be installed inside the screening machine cover 2 by welding or bolting, to enhance the stability of the overall structure. The material dispersing tooth 84 is a toothed structure used in conjunction with the material dispersing mechanism 6, which can be made of high-hardness alloy materials, to improve material dispersing efficiency.

[0034] In detail, the screen drum 81 achieves stable rotational motion through a combination design of the cylinder bearing seat 82 and bearing support 83. This structure not only effectively avoids displacement deviations caused by vibration but also maintains accuracy during the screening process. The screening holes on the side wall of the screen drum 81 classify the fertilizer by particle size during rotation, while the material-dispersing teeth 84 at the end form an engagement area with the material-dispersing mechanism 6, allowing large particles to directly enter the material-dispersing area without additional conveying. This design significantly shortens the material transport path. Simultaneously, the annular distribution of the material-dispersing teeth 84, rotating synchronously with the screen drum 81, achieves dynamic matching between the relative speed of the material-dispersing teeth and the material-dispersing mechanism 6 and the screening process, thus providing uniform material distribution and stable material-dispersing resistance. Furthermore, this solution reduces energy consumption through mechanical linkage and strengthens the connection between the screening and material-dispersing processes, improving overall work efficiency.

[0035] The above technical solutions not only solve the problem of limited screening efficiency in existing technologies, but also optimize the linkage between screening and bulk material processing, achieving a more efficient fertilizer processing process.

[0036] Please see Figures 1-4As shown, this application further proposes a bulk material mechanism 6 including a motor bracket 61 fixedly installed on the end cover 5 of the machine cover, a bulk material motor 62 fixedly installed on the motor bracket 61, the output shaft of the bulk material motor 62 passing through the end cover 5 and fixedly connected to a bulk material sleeve 63, a plurality of bulk material teeth 65 that cooperate with the bulk material teeth 84 to disperse fertilizer are fixedly provided on the outer periphery of the bulk material sleeve 63, and a plurality of pushing blades 64 arranged in a ring array are fixedly provided on the bulk material sleeve 63, the pushing blades 64 being used to push fertilizer particles to the bulk material teeth; a discharge trough 10 for discharging dispersed fertilizer is provided at the lower part of the screening machine cover 2 below the bulk material sleeve 63.

[0037] Specifically, the bulk material handling mechanism 6 refers to a device for handling oversized particles after screening, which can be implemented using a rotary bulk material handling mechanism structure. The bulk material cover 63 refers to a shell structure with a specific shape, which can be designed as cylindrical or conical, to provide a mounting base for the bulk material teeth 65 and form a bulk material chamber. The pusher blade 64 can be understood as a component that guides the flow of material; it can take the form of an arc-shaped plate or a spiral blade, with the purpose of evenly distributing fertilizer particles into the bulk material area.

[0038] In detail, this technical solution securely mounts the bulk material motor 62 onto the end cover 5 of the machine shroud via a motor bracket 61, ensuring the stability of the bulk material distribution process. When the bulk material motor 62 drives the bulk material cover 63 to rotate, the outer circumference of its bulk material teeth 65 and the end of the screening cylinder 8 form a dynamic bulk material distribution interaction. The annular array distribution design of the driving blades 64 can uniformly guide oversized particles after screening to the bulk material teeth area. This material pre-distribution mechanism effectively avoids the decrease in bulk material distribution efficiency caused by local accumulation. The outlet trough 10 is located directly below the bulk material cover 63, using gravity to accelerate the discharge of the material after bulking, preventing secondary agglomeration caused by material retention in the bulking area. Of particular note is the relative positional relationship between the driving blades 64 and the bulk material teeth. This design allows the material to acquire a certain initial velocity before entering the bulking area, enhancing the impact effect of the bulk material teeth on the particles. At the same time, the annular array distribution of the blades ensures the continuity and stability of the bulking process.

[0039] This application further proposes that a cleaning brush 11 is fixedly installed on the top inner side of the screening machine cover 2 for cleaning the bulk material motor 62 and the bulk material teeth 84.

[0040] Specifically, the cleaning brush 11 refers to a device with flexible or rigid bristles, which can be made of nylon, wire, or composite materials. Its purpose is to remove surface deposits through contact with rotating parts, maintaining normal equipment operation. The inner top of the screening machine cover 2 refers to the upper area inside the screening machine cover. This location is chosen based on material flow characteristics to preferentially intercept splashed wet particles, preventing their accumulation on critical components.

[0041] In detail, the cleaning brush 11 is fixed to the top of the inner side of the screening machine cover 2, allowing it to continuously contact the rotating bulk material teeth 84 and the stationary bulk material motor 62 housing. When the screen drum 81 rotates, the cleaning brush 11 achieves automatic cleaning through relative motion. This structure requires no additional power source and relies on the machine's own operation to complete the cleaning task. The cleaning brush 11 provides dual cleaning for both the bulk material motor 62 and the bulk material teeth 84, ensuring that the heat dissipation surface of the motor housing is free of residue, maintaining stable motor operation, and ensuring that the teeth of the bulk material teeth 84 remain smooth, allowing particles of different hardness to pass smoothly through the bulk material area without interference from residue. At the same time, this design significantly reduces the risk of equipment failure caused by particle adhesion, adapts to the working conditions of fluctuating moisture content in blended fertilizers, and provides a basic operational guarantee for the subsequent intelligent control of the speed of the bulk material motor 62.

[0042] The above technical solution effectively solves the problem that fertilizer granules tend to adhere to the surface of the dispersing mechanism 6 when the moisture content is high, avoiding the decrease in heat dissipation efficiency, blockage of the gap between the dispersing teeth, and reduction in dispersing efficiency, thereby improving the stability of equipment operation and reducing maintenance frequency.

[0043] This application further proposes that the bulk material motor 62 is a variable frequency motor equipped with a frequency converter, and a high-precision current sensor is installed on the power line of the bulk material motor 62 to monitor the operating current of the motor in real time; an industrial-grade programmable logic controller or a dedicated industrial controller is set on the main frame 1, which interacts with the frequency converter and the current sensor to adjust the speed of the bulk material motor 62 according to the type of fertilizer.

[0044] Specifically, a frequency converter is a power electronic device that can change the output frequency to adjust the speed of a motor. It can be implemented using AC-DC-AC converters, direct frequency converters, etc. In practical applications, the frequency converter controls the speed of the bulk material motor 62 by adjusting the output frequency, thereby adapting to the bulk material requirements of fertilizer granules of varying hardness. A current sensor is a device that converts a current signal into a measurable electrical signal. It can be implemented using Hall effect sensors, shunts, etc., and its purpose is to acquire real-time operating status information of the bulk material motor 62. An industrial-grade programmable logic controller (PLC) or dedicated industrial controller is an automated control device with powerful data processing capabilities. It can analyze and process the collected current signal through preset algorithms and send adjustment commands to the frequency converter.

[0045] In detail, when fertilizer granules enter the bulk material area, the feeding motor 41 drives the screen drum 81 and the feeding shaft 42 to rotate, initiating the initial screening process. For oversized fertilizer granules, the feeding auger 43 pushes them between the first bulk material tooth 84 and the second bulk material tooth 65 for bulking. At this time, the current sensor monitors the load current change of the bulk material motor 62 in real time, and this current value directly reflects the resistance encountered by the bulk material. When the load current is detected to be continuously higher than the preset hard particle threshold, it indicates that harder particles are being processed or the bulk material resistance is increasing. The controller immediately sends a command to the frequency converter to gradually increase the speed of the bulk material motor 62. This speed increase will simultaneously increase the reverse speed of the cylinder bearing seat 82 and the bulk material sleeve 63, thereby enhancing the relative movement speed and impact, shearing or crushing force between the first bulk material tooth 84 and the second bulk material tooth 65, ensuring that hard particles can be efficiently and thoroughly bulked. Conversely, when the load current is consistently below the preset soft particle threshold, indicating that softer particles are being processed or the resistance of the bulk material is decreasing, the controller sends a command to the frequency converter to reduce the rotational speed. By reducing the relative speed and force of the material handling teeth, over-crushing of soft particles is effectively avoided, thereby reducing the generation of fine dust and material loss. This solution, by introducing a variable frequency motor, current sensor, and intelligent controller to construct a closed-loop feedback system, achieves dynamic adaptive adjustment of the bulk material process, ensuring sufficient dispersion of hard particles while avoiding over-crushing of soft particles.

[0046] This application further proposes a method for the controller to adjust the speed of the bulk material motor 62 according to the fertilizer type. After the fertilizer is fed into the feed cylinder 3, the feeding motor 41 starts at a preset reference speed under the initial command of the controller, driving the screen drum 81 and the feeding shaft 42 to rotate for preliminary screening. When oversized fertilizer particles are pushed between the first and second bulk material teeth 84 and 65 by the feeding spiral blades 43, the current sensor will monitor the load current of the bulk material motor 62 in real time. If the controller detects that the load current is continuously higher than the preset hard particle threshold, it indicates that harder particles are being processed or the bulk resistance is increasing. The controller will immediately send a command to the frequency converter to gradually increase the speed of the bulk material motor 62. The speed of the bulk material motor 62 increases; the increase in the speed of the bulk material motor 62 will simultaneously increase the reverse speed of the cylinder bearing seat 82 and the bulk material cover 63, thereby increasing the relative motion speed and the impact, shearing or crushing force between the first bulk material tooth 84 and the second bulk material tooth 65, ensuring that hard particles can be efficiently and thoroughly dispersed; if the controller detects that the load current is continuously lower than the preset soft particle threshold, it indicates that softer particles are being processed or the bulk material resistance is reduced, and the controller will send a command to the frequency converter to gradually reduce the speed of the bulk material motor 62; the reduction in motor speed will reduce the relative motion speed and force of the bulk material teeth, effectively avoiding over-crushing of soft particles, thereby reducing the generation of fine dust and material loss.

[0047] Specifically, the controller refers to an industrial-grade programmable logic controller or a dedicated industrial controller used to receive current sensor signals and control the inverter output according to preset logic. It can dynamically adjust the speed of the bulk material handling motor 62 through built-in algorithms. In practical applications, the controller can be implemented using an intelligent control system based on a PID control algorithm, aiming to adapt to the bulk material requirements of particles with different hardness through precise speed adjustment. The current sensor is a high-precision sensor used to collect the operating current of the bulk material handling motor 62 in real time. It can be implemented using a Hall effect sensor or a shunt-type current detection device, aiming to accurately reflect load changes during the bulk material handling process.

[0048] In detail, this solution achieves dynamic adaptive adjustment of the bulk material process by constructing a closed-loop control mechanism of current feedback and speed regulation. When fertilizer particles enter the bulk material area, the current sensor monitors the load current change of the bulk material motor 62, converting the physical bulk material resistance into electrical signal parameters. The controller compares the real-time current value with a preset threshold. When the hard particle threshold is exceeded, the motor speed is increased through the frequency converter. This speed increase not only directly enhances the mechanical force of the bulk material teeth, but more importantly, through the linkage structure of the cylinder bearing seat 82 and the bulk material cover 63, it makes the screen roller 81 and the bulk material cover 63 form a stronger reverse motion tendency, thereby creating a more intense shearing and crushing effect between the bulk material teeth. When the current value is lower than the soft particle threshold, the controller actively reduces the speed design, thereby reducing the relative motion intensity between the bulk material teeth and matching the bulk material force with the material characteristics. This flexible bulk material method is particularly suitable for soft particles with high moisture content or low density, effectively suppressing over-crushing while ensuring the bulk material effect.

[0049] Furthermore, this scheme mechanically links the speed adjustment of the bulk material motor 62 with the rotation state of the screening cylinder 8, so that the entire adjustment process not only involves the bulk material itself, but also simultaneously affects the motion parameters of the screening process, forming a systematic control strategy for coordinated adjustment of bulk material and screening. This design breaks through the limitations of the traditional fixed-parameter bulk material mode, and achieves dual optimization of bulk material efficiency and material adaptability through closed-loop control of real-time sensing, intelligent decision-making and dynamic adjustment.

[0050] Please see Figures 6-9 As shown, this application further discloses the specific structure of the screening frame 9 of the above-mentioned fertilizer screening device. The screening frame 9 includes a receiving tray 91 disposed inside the screening machine cover 2. A screen 92 is detachably installed on the inner side of the receiving tray 91. The screen 92 is installed at an angle inside the receiving tray 91, with the side closer to the feed cylinder 3 being higher than the side farther from the feed cylinder 3. The screen 92 is provided with a plurality of screen holes, and the screen holes on the side closer to the feed cylinder 3 are smaller than the screen holes on the side farther from the feed cylinder 3.

[0051] Specifically, the receiving tray 91 is a supporting structure used to receive fertilizer particles falling from the screening cylinder 8 and guide their flow. It can be made of stamped metal sheet or injection molded engineering plastic, and its purpose is to provide a stable supporting platform to ensure the stability of the screening process. The screen 92 is a filter component with different pore sizes. It can be detachably connected to the receiving tray 91 by bolts, clips, or magnetic attraction, which is intended to facilitate replacement and maintenance, and to adapt to the grading requirements of fertilizers with different particle sizes. Inclined installation refers to the arrangement of the screen 92 at a certain angle within the receiving tray 91. This can be achieved by adjusting the bracket or positioning pins, and its purpose is to use gravity to promote material flow and avoid particle accumulation.

[0052] In detail, this scheme, by installing the screen 92 at an angle within the receiving tray 91, allows fertilizer particles to move continuously forward along the inclined direction under gravity, effectively preventing particle accumulation on the screen surface. The gradient distribution of screen apertures, from small to large along the material flow direction, enables step-by-step screening and separation of fertilizer particles of different sizes. Smaller particles preferentially pass through the near-end screen apertures, while larger particles gradually pass through the progressively larger apertures during movement, completing the grading process. This grading mechanism significantly improves screening accuracy and efficiency, solving the problem of incomplete screening in traditional single-layer screen drums. Furthermore, the detachable installation of the screen 92 facilitates equipment maintenance and process adjustments; different screen sizes can be used to meet diverse screening needs. This design, combined with the preliminary screening function of the screening cylinder 8, forms a complete multi-stage screening system, providing a more precise particle size classification basis for the subsequent independent collection by the discharge funnel 7.

[0053] This application further proposes an improved scheme for the screening frame 9 in the above-mentioned fertilizer screening device, specifically including two sets of limiting guide rails 93 fixedly installed on the inner wall of the screening machine cover 2, with limiting sliders 94 slidably connected at the limiting guide rails 93, and the limiting sliders 94 fixedly connected to the outer wall of the receiving plate 91; multiple vibration springs 96 are fixedly installed on the side wall of the receiving plate 91 near the feeding cylinder 3, and the side of the vibration springs 96 away from the receiving plate 91 is fixedly connected to the inner wall of the screening machine cover 2. The elasticity of the vibration springs 96 drives the receiving plate 91 to slide back and forth along the limiting guide rails 93 to vibrate and screen the fertilizer.

[0054] The limiting guide rail 93 refers to the track structure that provides linear motion guidance for the receiving tray 91, and it can be implemented using metal guide rails, plastic guide rails, or composite material guide rails. The vibration spring 96 can be understood as an elastic element, and it can be implemented using helical springs, leaf springs, or other mechanical elements with elastic deformation characteristics. The limiting slider 94 is a sliding component used in conjunction with the limiting guide rail 93, and it can be implemented using a ball bearing slider, sliding bearing, or self-lubricating slider structure.

[0055] Specifically, this design, through the coordinated design of the limiting guide rail 93 and the limiting slider 94, ensures that the receiving tray 91 maintains a precise linear motion trajectory during vibration, avoiding uneven screening caused by shaking. The vibration spring 96 is installed on the side of the receiving tray 91 near the feed cylinder 3, effectively utilizing the natural excitation generated during system operation. Through the elastic deformation of the spring, energy is stored and released, driving the receiving tray 91 to slide back and forth along the limiting guide rail 93, forming continuous vibration. This structural design requires no additional power source and cleverly utilizes mechanical elasticity to achieve automatic vibration.

[0056] Furthermore, after the fertilizer granules fall into the receiving tray 91, the reciprocating motion of the vibrating spring 96 causes the receiving tray 91 to vibrate regularly, effectively preventing fertilizer from accumulating or getting stuck on the screen. Especially when processing sticky or fine particles, this vibration mechanism can significantly improve screening efficiency and particle separation accuracy. At the same time, since the vibration amplitude and frequency mainly depend on the characteristics of the vibrating spring 96, different spring parameters can be selected to adapt to the screening requirements of different materials, demonstrating good adaptability and adjustability.

[0057] The above technical solution not only solves the problem of fertilizer granules easily accumulating or getting stuck on the inclined screen, but also achieves automatic vibration without the need for an additional power source, effectively improving screening efficiency and particle separation accuracy while reducing the need for manual intervention. This design simplifies the equipment structure and reduces maintenance costs while ensuring screening performance.

[0058] This application further proposes that a linkage wedge 95 is fixedly installed on the upper end of the receiving tray 91 near the feeding cylinder 3, and a drive disk 85 is fixedly installed on the outer periphery of the screen roller 81. The end face of the drive disk 85 near the receiving tray 91 is provided with a plurality of drive wedge grooves 86 arranged in a ring array. The drive wedge grooves 86 are wedge-shapedly engaged with the linkage wedge 95. When the drive disk 85 rotates, the pressing of the linkage wedge 95 and the drive disk 85 drives the receiving tray 91 to slide back and forth along the limiting guide rail 93, and it is rebounded and reset by the elastic action of the vibration spring 96.

[0059] Specifically, the linkage wedge 95 refers to a mechanical transmission element with an inclined contact surface, which can be implemented using wedges at different angles. In practical applications, the selection of the wedge angle needs to comprehensively consider transmission efficiency and force distribution to ensure that excessive wear is avoided while transmitting driving force. The drive wedge groove 86 can be understood as a groove structure set on the surface of the drive disc 85, which can be designed as a straight line, an arc, or a multi-segment combination, with the purpose of achieving periodic cooperation with the linkage wedge 95. The vibration spring 96 is an element that provides elastic restoring force; it can be a cylindrical helical spring, a leaf spring, or other forms of elastic device, and its main purpose is to provide a stable restoring force for the reciprocating motion of the receiving disc 91.

[0060] In detail, this scheme converts the rotational motion of the screen drum 81 into the reciprocating vibration of the receiving disc 91 through a mechanical linkage structure. When the drive disc 85 rotates synchronously with the screen drum 81, the annularly distributed drive wedge grooves 86 on its surface periodically contact the linkage wedge block 95. When the wedge groove 86 and the wedge block 95 are engaged, their wedge-shaped surfaces press against each other, pushing the receiving disc 91 to slide away from the feed cylinder 3, overcoming the resistance of the vibration spring 96. When the wedge groove 86 disengages from the wedge block 95, the vibration spring 96 releases its stored energy, causing the receiving disc 91 to slide back to its original position. This design achieves three core functions: First, it utilizes the rotational kinetic energy of the screen drum 81 as the source of vibration driving force, eliminating the need for an independent vibration motor; second, the vibration frequency is physically linked to the rotational speed of the screen drum 81, ensuring dynamic matching between the screening vibration intensity and the material flow rate; third, the intermittent contact characteristics between the wedge block 95 and the wedge groove 86 cause the receiving disc 91 to generate pulsed vibration, which helps prevent screen clogging and improves the fine particle throughput. The guiding cooperation between the limit guide rail 93 and the slider 94 ensures the stability of the vibration direction and avoids structural wear caused by movement deviation.

[0061] The above technical solution not only solves the problem of requiring additional vibration drive components in traditional vibrating screening, but also achieves dynamic matching between vibration frequency and screening requirements. Especially when processing fertilizers with different particle size distributions, it can automatically adjust the vibration intensity according to the rotational speed of the screen drum 81, significantly improving screening efficiency and effectiveness. Furthermore, this solution works organically with the rotational state of the screen drum 81, making the entire screening process more coordinated and efficient, demonstrating the ingenuity and practicality of the design.

[0062] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fertilizer screening device, comprising a main frame (1), a screening cover (2) fixedly mounted on the upper end of the main frame (1), a feed cylinder (3) fixedly mounted on one end of the screening cover (2), a feeding port provided on the feed cylinder (3), and a hopper installed at the feeding port via a flange; a screening cylinder (8) connected to the outlet of the feed cylinder (3) is provided inside the screening cover (2), and a feeding drive (4) for conveying fertilizer is installed at the end of the feed cylinder (3) away from the screening cover (2); a plurality of discharge funnels (7) for independently discharging the fertilizer after screening are provided on the main frame (1); characterized in that: The screening machine cover (2) is fixedly provided with a cover end cap (5) on the side away from the feed cylinder (3). A dispersing mechanism (6) for dispersing fertilizer is installed on the cover end cap (5). A screening frame (9) is provided on the lower inner side of the screening machine cover (2). The screening frame (9) is located between the discharge funnel (7) and the screening cylinder (8) for further screening the fertilizer screened in the screening cylinder (8).

2. The fertilizer screening device according to claim 1, characterized in that: The feeding drive (4) includes a feeding motor (41) fixedly installed on the feeding cylinder (3). The output end of the feeding motor (41) is fixedly connected to a feeding shaft (42). The feeding shaft (42) passes through the feeding cylinder (3) and the screening cylinder (8). The outer periphery of the feeding shaft (42) located inside the feeding cylinder (3) and the screening cylinder (8) is fixedly provided with feeding spiral blades (43) for spirally pushing fertilizer. The feeding shaft (42) is provided with multiple linkage support rods (44) arranged in a ring array at the outlet of the feeding cylinder (3). The linkage support rods (44) are fixedly connected to the screening cylinder (8) for synchronously driving the screening cylinder (8) to rotate.

3. The fertilizer screening device according to claim 1, characterized in that: The screening cylinder (8) includes a screen roller (81). The side wall of the screen roller (81) is evenly provided with a number of screening holes. Both ends of the screen roller (81) are rotatably connected to the inner wall of the screening machine cover (2) through the cylinder bearing seat (82). The cylinder bearing seat (82) is fixedly installed inside the screening machine cover (2) through the bearing bracket (83). The side of the screen roller (81) away from the feed cylinder (3) is provided with a number of material dispersing teeth (84) that cooperate with the material dispersing mechanism (6).

4. The fertilizer screening device according to claim 3, characterized in that: The bulk material mechanism (6) includes a motor bracket (61) fixedly installed on the end cover (5) of the machine cover. A bulk material motor (62) is fixedly installed on the motor bracket (61). The output shaft of the bulk material motor (62) passes through the end cover (5) of the machine cover and is fixedly connected to a bulk material cover (63). Several bulk material teeth (65) that cooperate with the first bulk material tooth (84) to disperse fertilizer are fixedly provided on the outer periphery of the bulk material cover (63). Several pushing blades (64) arranged in a ring array are fixedly provided on the bulk material cover (63). The pushing blades (64) are used to push fertilizer particles to the bulk material teeth. The lower part of the screening machine cover (2) located below the bulk material cover (63) is provided with an outlet groove (10) for discharging the dispersed fertilizer.

5. A fertilizer screening device according to claim 4, characterized in that: A cleaning brush (11) for cleaning the bulk material motor (62) and the bulk material tooth (84) is fixedly installed on the top inner side of the screening machine cover (2).

6. A fertilizer screening device according to claim 4, characterized in that: The bulk material motor (62) is a variable frequency motor equipped with a frequency converter. A high-precision current sensor is installed on the power line of the bulk material motor (62) to monitor the working current of the motor in real time. An industrial-grade programmable logic controller or a dedicated industrial controller is provided on the main frame (1). The controller interacts with the frequency converter and the current sensor to adjust the speed of the bulk material motor (62) according to the type of fertilizer.

7. A fertilizer screening device according to claim 5, characterized in that: The method by which the controller adjusts the speed of the bulk material motor (62) according to the type of fertilizer is as follows: After the fertilizer is fed into the feed cylinder (3), the feeding motor (41) starts at the preset reference speed under the initial command of the controller, driving the screen drum (81) and the feeding shaft (42) to rotate for preliminary screening; When large-sized fertilizer particles are pushed between the first and second granular teeth (84) and granular teeth (65) by the feeding screw (43) for granulation, the current sensor will monitor the load current of the granular motor (62) in real time. The magnitude of the load current directly reflects the resistance borne by the granular material, that is, the hardness of the granular material or the difficulty of granulation. If the controller detects that the load current is continuously higher than the preset hard particle threshold, it indicates that it is processing harder particles or the resistance of the bulk material is increasing. The controller will immediately send a command to the frequency converter to gradually increase the speed of the bulk material motor (62). The increase in the speed of the bulk material motor (62) will simultaneously increase the reverse speed of the cylinder bearing seat (82) and the bulk material cover (63), thereby increasing the relative speed and the impact, shearing or crushing force between the first bulk material tooth (84) and the second bulk material tooth (65), ensuring that the hard particles can be dispersed efficiently and thoroughly. If the controller detects that the load current is consistently lower than the preset soft particle threshold, indicating that it is processing softer particles or that the resistance of the bulk material is decreasing, the controller will send a command to the frequency converter to gradually reduce the speed of the bulk material motor (62).

8. A fertilizer screening device according to claim 3, characterized in that: The screening frame (9) includes a receiving tray (91) set inside the screening machine cover (2). A screen (92) is detachably installed on the inner side of the receiving tray (91). The screen (92) is installed at an angle inside the receiving tray (91) and the side closer to the feed cylinder (3) is higher than the side away from the feed cylinder (3). The screen (92) is provided with a number of screen holes, and the screen holes on the side closer to the feed cylinder (3) are smaller than the screen holes on the side away from the feed cylinder (3).

9. A fertilizer screening device according to claim 8, characterized in that: The screening frame (9) also includes two sets of limiting guide rails (93) fixedly installed on the inner wall of the screening machine cover (2). Limiting sliders (94) are slidably connected to the limiting guide rails (93). The limiting sliders (94) are fixedly connected to the outer wall of the receiving tray (91). Multiple vibration springs (96) are fixedly installed on the side wall of the receiving tray (91) near the feeding cylinder (3). The side of the vibration springs (96) away from the receiving tray (91) is fixedly connected to the inner wall of the screening machine cover (2). The elasticity of the vibration springs (96) drives the receiving tray (91) to slide back and forth along the limiting guide rails (93) to vibrate and screen the fertilizer.

10. A fertilizer screening device according to claim 9, characterized in that: A linkage wedge (95) is fixedly installed on the upper end of the receiving tray (91) near the feeding cylinder (3). A drive disk (85) is fixedly installed on the outer periphery of the screen roller (81). A plurality of drive wedge grooves (86) are arranged in a ring array on the end face of the drive disk (85) near the receiving tray (91). The drive wedge grooves (86) are wedge-shapedly engaged with the linkage wedge (95). When the drive disk (85) rotates, the pressing of the linkage wedge (95) and the drive disk (85) drives the receiving tray (91) to slide back and forth along the limiting guide rail (93), and the elastic action of the vibration spring (96) causes it to rebound and reset.

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