Vibrating screen

Abstract

The utility model discloses a vibrating screen, which is used for screening polymer particles cut by a granulator and comprises a feeding component, a vibrating component, a discharging component, a vibrating component, a vibrating component, a vibrating component and a vibrating component, the feeding component comprises a feeding pipeline, and the polymer particles cut by the granulator are conveyed by the feeding pipeline; the screening assembly is arranged at the outlet of the feeding pipeline and comprises a screening surface, and the polymer particles flow into the screening surface through the feeding pipeline; the material pressing roller is rotationally connected with the screening assembly and arranged above the screening surface, a gap is formed between the material pressing roller and the screening surface, and an adsorption part is arranged in the material pressing roller; wherein when the screening assembly screens the polymer particles, the pressing roller can roll and grind the polymer particles so as to separate the adhered polymer particles, and the adsorption part is used for adsorbing the polymer particles containing iron impurities. By adopting the technical scheme, adhered polymer particles can be separated, iron impurities in the polymer particles can be cleaned, the qualified rate of the polymer particles is improved, the labor intensity of workers is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of mechanical equipment, and in particular to a vibrating screen. Background Technology

[0002] In the production of polymer pellets, the material is drawn from the extruder to the pelletizer and then pelletized. After pelletizing, the pellets need to be screened by a vibrating screen before entering the homogenization chamber. During the production process, due to the high local temperature of the material, some polymer pellets after pelletizing by the pelletizer stick together, which does not meet the standards of the finished pellets. At the same time, the sticky polymer pellets will cause the vibrating screen to become clogged. Also, some impurities containing iron will be introduced into the polymer pellets during the production process, causing the polymer pellets to be unqualified as a whole. If the impurities containing iron enter the homogenization chamber, the material in the entire homogenization chamber will be unqualified, which will require manual screening. This not only greatly increases the labor intensity of workers, but also seriously reduces production efficiency. Utility Model Content

[0003] The purpose of this invention is to solve the technical problems of existing vibrating screens being unable to handle polymer particle adhesion and the inability to remove iron impurities within the polymer particles. This invention provides a vibrating screen that can separate adhered polymer particles and remove iron impurities from the polymer particles, thereby improving the yield of qualified polymer particles, reducing the labor intensity of workers, and increasing production efficiency.

[0004] To address the aforementioned technical problems, this utility model discloses a vibrating screen for screening polymer particles cut by a pelletizer, comprising:

[0005] The feeding assembly includes a feeding pipe through which polymer particles cut by the pelletizer are transported.

[0006] A screening component is located at the outlet of the feeding pipe. The screening component includes a screen surface, and polymer particles flow into the screen surface through the feeding pipe.

[0007] The pressure roller is rotatably connected to the screening assembly and is positioned above the screen surface with a gap between it and the screen surface. An adsorption element is installed inside the pressure roller.

[0008] In this component, when the screening component screens polymer particles, the pressure roller can roll and crush the polymer particles to separate the polymer particles that are stuck together, and the adsorption component is used to adsorb polymer particles containing iron impurities.

[0009] By adopting the above technical solution, the adhering polymer particles can be separated and the iron impurities in the polymer particles can be removed, thereby improving the qualification rate of polymer particles, reducing the labor intensity of workers, and improving production efficiency.

[0010] According to another specific embodiment of the present invention, the screening component further includes:

[0011] The screen box has an opening at the top and a cavity inside for receiving polymer particles. The screen surface is located at the opening at the top of the screen box and is fixedly connected to the screen box.

[0012] The motor is located on one side of the screen box. The motor is connected to the screen box through a spring bracket. An eccentric block is installed on the drive shaft of the motor. The eccentric block is connected to the spring bracket. When the motor drives the eccentric block to rotate, the eccentric block drives the spring bracket connected to it and the screen box connected to the spring bracket to vibrate back and forth.

[0013] According to another specific embodiment of the present invention, the screening component further includes two guide plates. The guide plates are thin metal plates disposed on the screen surface and arranged on both sides of the screen surface along the reciprocating vibration direction of the screen box. They are used to change the movement trajectory and speed of the polymer particles and prevent the polymer particles from accumulating.

[0014] According to another specific embodiment of the present invention, the screen box further includes a discharge port, which is opened on the side of the screen box near the bottom. A guide plate inclined towards the discharge port is provided inside the screen box. The polymer particles move along the guide plate to the discharge port and flow into the next process from the discharge port.

[0015] According to another specific embodiment of the present invention, the pressure roller disclosed in this embodiment includes:

[0016] The roller body is cylindrical, with a shaft head at the center of each end. Bearings are mounted on the shaft heads, and the roller body is rotated and mounted on the screen box via the bearings. The inside of the roller body is hollow.

[0017] The drive unit is connected to one of the shaft heads of the roller body and is used to drive the roller body to rotate.

[0018] An adsorption element is installed on the inner wall of the roller body. When the roller body rotates, the adsorption element is used to adsorb iron-containing polymer particles onto the surface of the roller body.

[0019] According to another specific embodiment of the present invention, the adsorption element is a permanent magnet, which is fixedly installed on the inner side wall of the roller body.

[0020] According to another specific embodiment of the present invention, the adsorption element is an electromagnet, which is disposed in the roller body and has a gap with the inner side wall of the roller body. The electromagnet changes the magnetic force of the electromagnet by adjusting the current supplied to the electromagnet, which is used to adjust the adsorption intensity of the pressure roller according to the amount of polymer particles on the screen surface.

[0021] According to another specific embodiment of the present invention, the embodiment of the present invention also includes a metal detector, which is set at the outlet of the screening component near the feeding pipe. The metal detector includes an oscillator and a detection coil. The oscillator drives the detection coil to detect the amount of iron-containing impurities in the polymer particles using a high-frequency alternating magnetic field. The electromagnet adjusts the current supplied to the electromagnet according to the detection result of the metal detector.

[0022] According to another specific embodiment of the present invention, the present invention discloses that a scraper is also provided on the roller body. The scraper is located on one side of the roller body. When the roller body adsorbs iron-containing polymer particles onto the surface of the roller body, the polymer particles rotate with the roller body to the scraper side. The scraper scrapes the iron-containing polymer particles off the surface of the roller body and moves with the scraper to the collection device.

[0023] According to another specific embodiment of the present invention, the embodiment of the present invention also includes a cleaning and blowing device disposed at the scraper. The cleaning and blowing device includes a nozzle facing the scraper and is used to spray a high-pressure pulsed airflow onto the scraper to blow the iron-containing polymer particles on the scraper into the collection device.

[0024] According to another specific embodiment of the present invention, the roller body surface is provided with a serrated pattern, and the serrated pattern surface is coated with a tungsten carbide coating. The serrated pattern is used to increase the impact point of crushing, and the tungsten carbide coating is used to increase the service life of the serrated pattern.

[0025] According to another specific embodiment of the present invention, the embodiment of the present invention discloses that it also includes an air cooling device, which is disposed at the outlet of the feeding pipe, and includes an air outlet facing the screen surface, for blowing air onto the polymer particles on the screen surface to reduce the temperature of the polymer particles. Attached Figure Description

[0026] Figure 1 A schematic diagram of the structure of an embodiment of the vibrating screen of this utility model is shown. Figure 1 ;

[0027] Figure 2 A schematic diagram of the structure of an embodiment of the vibrating screen of this utility model is shown. Figure 2 ;

[0028] Figure 3 A schematic diagram of the structure of the pressure roller in an embodiment of the vibrating screen of this utility model is shown. Figure 1 ;

[0029] Figure 4 A schematic diagram of the structure of the pressure roller in an embodiment of the vibrating screen of this utility model is shown. Figure 2 . Detailed Implementation

[0030] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Although the description of this utility model will be presented in conjunction with preferred embodiments, this does not mean that the features of this utility model are limited to this embodiment. On the contrary, the purpose of describing the utility model in conjunction with the embodiments is to cover other options or modifications that may be derived based on the claims of this utility model. To provide a deep understanding of this utility model, many specific details will be included in the following description. This utility model may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this utility model, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0031] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.

[0033] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0034] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0035] Reference Figure 1 and Figure 2 This application provides a vibrating screen for screening polymer particles cut by a pelletizer, comprising:

[0036] The feeding assembly 1 includes a feeding pipe 11, through which polymer particles cut by the pelletizer are conveyed;

[0037] Screening component 2 is located at the outlet of feeding pipe 11. Screening component 2 includes screen surface 21, on which polymer particles flow into the screen surface 21 through feeding pipe 11.

[0038] The pressing roller 3 is rotatably connected to the screening assembly 2 and is positioned above the screen surface 21 with a gap between it and the screen surface 21. An adsorption element 32 is provided inside the pressing roller 3.

[0039] When the screening component 2 screens the polymer particles, the pressure roller 3 can roll and crush the polymer particles to separate the adhering polymer particles, and the adsorption component 32 is used to adsorb polymer particles containing iron impurities.

[0040] In this embodiment, the feeding pipe 11 is made of non-metallic material to adapt to the conveying environment of polymer particles and ensure long-term stability. Its inner diameter is designed according to the production and flow requirements of the polymer particles; in this application, it is between 10 and 30 cm to ensure smooth flow of the polymer particles without clogging. The inner wall of the pipe is polished to reduce friction during polymer particle flow and prevent polymer particles from accumulating on the pipe wall.

[0041] One end of the feeding pipe 11 is connected to the discharge port 25 of the pelletizer via a flange. The connection is sealed with a high-temperature resistant and wear-resistant rubber gasket to prevent material leakage during conveying. The other end extends above the screening component 2, and the outlet is connected to the inlet of the screening component 2 to ensure that polymer particles can flow accurately into the screen surface 21.

[0042] The screen surface 21 is woven from high-strength stainless steel wire, possessing excellent wear resistance and toughness, capable of withstanding the crushing of the pressure roller 3 and the friction of polymer particles. The screen aperture size is customized according to the particle size specifications of the polymer particles to be screened. In this application, taking the screening of qualified polymer particles with a particle size of 2-5 mm as an example, the screen aperture size is set to about 5 mm to ensure that polymer particles smaller than the screen aperture size can pass through smoothly, while polymer particles larger than the screen aperture size remain on the screen surface 21 for subsequent processing.

[0043] The screen surface 21 is woven from high-strength stainless steel wire, possessing excellent wear resistance and toughness. This allows the screen surface 21 to withstand prolonged crushing by the pressure roller 3 and repeated friction from a large number of polymer particles, ensuring that the screen surface 21 will not break or deform during long-term use, maintaining stable screening performance, extending the service life of the screen surface 21, and reducing equipment maintenance costs and replacement frequency. The screen aperture size is customized according to the required polymer particle size specifications, accurately screening out polymer particles that do not meet the size requirements. This ensures that the final product has uniform polymer particle size, meets quality standards, and facilitates subsequent product processing and use.

[0044] The pressure roller 3 is made of high-strength carbon steel or alloy steel with a surface hardness of HRC40-50, providing sufficient crushing performance and wear resistance. The length of the pressure roller 3 is determined by the width of the screen surface 21 and the polymer particle processing capacity; its length is less than the width of the screen surface 21 and can cover most of the screen surface 21 area, achieving effective crushing of the polymer particles. The pressure roller 3 is rotatably connected to the screening assembly 2, and the adsorption element 32 installed inside the pressure roller 3 is used to adsorb polymer particles containing iron impurities.

[0045] The pressure roller 3 is made of high-strength carbon steel or alloy steel and has undergone quenching and tempering treatment, giving it a high surface hardness. When rolling and crushing polymer particles, it can apply sufficient pressure to effectively separate polymer particles that are stuck together, ensuring the dispersion of polymer particles and improving screening accuracy. Furthermore, its excellent wear resistance ensures that the roller surface will not easily wear down during prolonged contact and friction with polymer particles, maintaining a stable crushing effect and reducing problems such as uneven crushing of polymer particles and missed or stuck polymer particles caused by roller wear. This extends the service life of the pressure roller 3 and reduces equipment maintenance costs and replacement frequency. The appropriate roller size design allows it to cover most of the screen surface 21, ensuring comprehensive crushing of polymer particles on the screen surface 21 and avoiding untreated areas, further improving the separation effect of stuck polymer particles and the overall screening quality.

[0046] By adopting the above technical solution, the adhering polymer particles can be separated and the iron impurities in the polymer particles can be removed, thereby improving the qualification rate of polymer particles, reducing the labor intensity of workers, and improving production efficiency.

[0047] In one feasible embodiment, the screening assembly 2 further includes a screen box 22 with an opening at the top. The interior of the screen box 22 is a cavity for receiving polymer particles. The screen surface 21 is disposed at the opening at the top of the screen box 22 and is fixedly connected to the screen box 22. A motor 23 is disposed on one side of the screen box 22. The motor 23 is connected to the screen box 22 through a spring bracket 24. An eccentric block is disposed on the drive shaft of the motor 23. The eccentric block is connected to the spring bracket 24. When the motor 23 drives the eccentric block to rotate, the eccentric block drives the spring bracket 24 connected to it and the screen box 22 connected to the spring bracket 24 to reciprocate.

[0048] In this embodiment, the screen box 22 is generally rectangular in shape (it can also be designed into other suitable shapes according to the actual site and production needs), with an opening at the top to facilitate the falling of polymer particles from above. The size of its internal cavity is determined according to the amount of polymer particles being processed, ensuring sufficient space for the polymer particles to tumble and be screened fully during vibration. The walls of the cavity and bottom are welded from steel plates, ensuring that the overall structure has sufficient strength and rigidity to withstand the weight of the screen surface 21, the motor 23, and the polymer particles, and will not easily deform during long-term vibration. The screen box 22 is made of high-quality carbon steel, which has good welding performance and is easy to manufacture into complex screen box structures. The screen box 22 is rust-proofed to resist the corrosion of moisture and corrosive substances present in the production environment, extending the service life of the screen box 22.

[0049] The rectangular screen box 22 has a simple structure and high space utilization, making it easy to arrange and install in the production workshop. Made of carbon steel with rust-proofing treatment, it ensures structural strength while reducing manufacturing costs, extending service life, decreasing the frequency of equipment replacement, and improving economic efficiency. Furthermore, the robust box wall structure effectively protects the internal screen surface 21 and the screening process, preventing external factors from interfering with the screening operation and providing a stable screening environment for polymer particles.

[0050] At the edge of the opening at the top of the screen box 22, an inward-facing groove is machined. The width and depth of the groove are adapted to the frame of the screen surface 21. After the frame of the screen surface 21 is embedded in the groove, it is further secured with bolts. The bolts are evenly distributed along the groove, with one bolt every 10-20 cm in this application, ensuring a firm connection between the screen surface 21 and the screen box 22 and preventing loosening or displacement during vibration. A rubber sealing strip is also placed inside the groove. After the screen surface 21 is installed, it is compressed and deformed, filling the gap between the screen surface 21 and the groove, thus providing a seal and ensuring that the screening process takes place in a relatively closed environment, avoiding material loss and pollution to the surrounding environment.

[0051] The combination of slots and bolts ensures the secure installation of the screen surface 21 while facilitating its disassembly and replacement. When the screen surface 21 is damaged or clogged and requires repair or replacement, operators can quickly perform the necessary procedures, reducing equipment downtime and improving production efficiency. The rubber sealing strip effectively prevents material leakage, avoiding waste, maintaining a clean production site, reducing potential safety hazards caused by spilled materials, and helping to maintain a stable screening environment, ensuring accurate screening results.

[0052] Based on the dimensions of the screen box 22, the expected weight of polymer particles to be carried, and the required vibration intensity, a three-phase asynchronous vibratory motor 23 with a power output between 0.5 and 5 kW and a speed typically between 1000 and 1500 rpm is selected. The motor 23 is mounted on a motor mount on one side of the screen box 22. The motor mount is fixed to the side wall of the screen box 22 by welding or bolting, ensuring a stable installation position and accurate relative positioning between the motor 23 and the screen box 22. The height and angle of the motor mount ensure that the drive shaft of the motor 23 is aligned with the vibration direction of the screen box 22, ensuring that the vibration is effectively transmitted to the screen box 22 and the screen surface 21, thereby improving screening efficiency.

[0053] The selection of the three-phase asynchronous vibration motor 23, due to its mature technology and wide application, ensures high reliability, low failure probability, and easy maintenance during equipment operation. It can adapt to the demands of long-term, high-intensity industrial production, guaranteeing the continuity of the entire screening process. The rationally designed installation position of the motor 23 ensures the accuracy of the vibration direction and the high efficiency of vibration transmission, enabling stable and effective vibration of the screen box 22 and screen surface 21. This improves the tumbling and screening effect of polymer particles on the screen surface 21, contributing to improved product screening quality and production efficiency.

[0054] The spring bracket 24 consists of multiple high-strength springs, of which helical springs are used in this application, and matching upper and lower connecting seats. The upper and lower connecting seats are respectively connected to the eccentric block on the drive shaft of the motor 23 and the side wall of the screen box 22. The connection method is bolt connection or welding to ensure that the connection is firm and reliable.

[0055] The spring support 24 utilizes the elastic properties of springs to convert the rotational motion of the motor 23 into the reciprocating linear vibration of the screen box 22 under the centrifugal force generated by the eccentric block, which is suitable for screening polymer particles. By adjusting the eccentricity of the eccentric block and the speed of the motor 23, the vibration parameters can be changed, allowing the vibrating screen to flexibly cope with different production conditions. For example, for polymer particles with small particle size and easy agglomeration, the vibration frequency and amplitude can be appropriately increased to enhance the dispersion and screening effect of polymer particles; while for polymer particles with larger particle size and better flowability, the vibration parameters can be reduced accordingly to avoid excessive jumping and splashing of polymer particles, ensuring the accuracy and stability of screening, thereby improving the adaptability of the equipment to different materials and the controllability of the screening effect.

[0056] When motor 23 is powered on and starts running, its drive shaft drives the eccentric block in high-speed circular motion. Because there is a certain eccentricity between the center of gravity of the eccentric block and the center of the drive shaft, periodic centrifugal force is generated during rotation. This centrifugal force acts on the connected spring support 24, causing the spring to elastically deform, which in turn drives the screen box 22 to reciprocate linearly under the elastic restoring force of the spring. By adjusting the eccentricity of the eccentric block and the rotational speed of motor 23, the amplitude and frequency of vibration can be changed to adapt to the screening requirements of polymer particles with different sizes and properties.

[0057] In one feasible embodiment, the screening component 2 further includes two guide plates, which are thin metal plates disposed on the screen surface 21 and arranged on both sides of the screen surface 21 along the reciprocating vibration direction of the screen box 22, to change the movement trajectory and speed of the polymer particles and prevent the polymer particles from accumulating.

[0058] In this embodiment, the guide plate is made of stainless steel sheet with a thickness of 2-5 mm. This material can withstand the corrosive effects of chemical substances from polymer particles and the influence of moisture in the production environment, ensuring stable performance and preventing rust and damage during long-term use. Simultaneously, it possesses sufficient strength and toughness to maintain its shape and prevent deformation under the impact of polymer particles and prolonged vibration, thus effectively guiding the movement trajectory of the polymer particles.

[0059] The guide plate is elongated, its length matching the length of the screen surface 21, and slightly shorter. Its width is determined based on the width of the screen surface 21 and the range of changes needed to the polymer particle trajectory, typically between 10 and 30 centimeters. One edge of the guide plate is straight, aligned with the edge of the screen surface 21, while the other edge is designed with a curved shape, such as an inward or outward arc, to better guide the polymer particles to disperse and move in different directions.

[0060] The guide plates are installed on both sides of the screen surface 21 along the reciprocating vibration direction of the screen box 22. Multiple metal mounting brackets (generally one every 20-30 cm) are pre-welded to the inner wall of the screen box 22 corresponding to the installation positions of the guide plates. The mounting brackets have screw holes machined into them. The guide plates are connected to these mounting brackets by bolts, ensuring that the guide plates are firmly fixed to their respective positions on both sides of the screen surface 21, preventing loosening or displacement during the vibration of the screen box 22 and the impact of polymer particles.

[0061] The installation angle between the guide plate and the screen surface 21 is adjustable. A movable connection structure with angle markings is used at the connection between the guide plate and the mounting bracket. By loosening the bolts, rotating the guide plate to the appropriate angle, and then tightening the bolts, the angle between the guide plate and the screen surface 21 can be changed. The angle can be adjusted between 10° and 60°, allowing operators to make precise adjustments based on the actual screening conditions.

[0062] The guide plate effectively avoids the problem of local accumulation of polymer particles on the screen surface 21 by changing the movement trajectory and speed of the polymer particles. During the vibration of the screen box 22, polymer particles may have originally accumulated in some areas due to inertia and other factors. However, the presence of the guide plate causes the polymer particles to change their movement path according to the guidance direction of the guide plate when they come into contact with it, and disperse to other areas of the screen surface 21. This ensures that the polymer particles are evenly distributed on the entire screen surface 21, thereby increasing the effective screening area of ​​the screen surface 21, avoiding the reduction in screening efficiency due to local blockage, and ensuring that the screening work can be carried out continuously and efficiently.

[0063] When polymer particles collide with the guide plate, their speed changes accordingly based on the angle and shape of the guide plate. Reducing the speed allows the polymer particles to remain on the screen surface 21 for a longer time, giving them a greater chance to pass through the screen openings. This speed adjustment increases the probability of accurately screening polymer particles, especially those with particle sizes close to the screen opening size or good flowability. For polymer particles that are stuck together, the guide plate's effect of changing their trajectory and speed may cause them to separate during the collision process, further improving the screening quality of the stuck polymer particles and ultimately helping to improve the quality and uniformity of the products produced in the entire screening process.

[0064] The adjustable angle design allows the guide plate to adapt to the screening needs of polymer particles with different types, sizes, and moisture content. For polymer particles with smaller size and poor flowability, the guide plate angle can be adjusted to make the movement trajectory of the polymer particles relatively gentle, preventing the polymer particles from accumulating too quickly at the edge of the screen surface 21. For polymer particles with larger size and easy to roll quickly, the guide plate angle can be appropriately increased to enhance the force of changing the movement direction of the polymer particles, guiding the polymer particles to roll and screen more fully on the screen surface 21. This improves the adaptability of the equipment to various material conditions, expands the scope of application of the equipment, and reduces the need to replace or adjust the equipment due to changes in materials.

[0065] In one feasible embodiment, the screen box 22 further includes a discharge port 25, which is located on the side of the screen box 22 near the bottom. The screen box 22 is provided with a guide plate that is inclined toward the discharge port 25. The polymer particles move along the guide plate to the discharge port 25 and flow into the next process from the discharge port 25.

[0066] In this embodiment, the discharge port 25 is located on the side wall of the screen box 22 near the bottom. Its height is determined based on the overall size of the screen box 22 and the characteristics of the polymer particles, and is approximately 10-30 cm from the bottom of the screen box 22. This ensures that qualified polymer particles passing through the screen can flow out smoothly while preventing large particles or impurities that have not been fully screened from flowing out prematurely. The shape of the discharge port 25 is usually rectangular, with its long side aligned with the length of the side wall of the screen box 22. The length of the short side is designed based on the expected material flow rate, generally between 10-20 cm, to meet the discharge requirements of different production scales.

[0067] The edges of the discharge port 25 are polished to be smooth and burr-free, preventing scratches on polymer particles or material blockage. A flange is installed around the discharge port 25, with multiple bolt holes evenly distributed on the flange (generally spaced 5-10 cm apart). Bolts can be used to tightly connect it to the feed port of subsequent conveying equipment, ensuring that the material can flow smoothly into the next process and preventing material leakage at the connection point.

[0068] The guide plate is made of wear-resistant plastic sheet or stainless steel sheet with a thickness of 3-6 mm, which has good wear resistance and a smooth surface, facilitating the sliding of polymer particles. Its overall shape is rectangular, with the length matching the width of the screen box 22. The width is determined based on the internal space of the screen box 22 and the position of the discharge port 25, generally between 20-50 cm. One side of the guide plate is welded and fixed to the inner wall of the screen box 22, while the other side slopes downwards towards the discharge port 25. The inclination angle is usually between 10° and 30°. This angle ensures that the particles slide smoothly under their own weight without causing excessive impact or splashing due to excessively high particle speed.

[0069] Inside the screen box 22, the flow guide plate is generally installed below the screen surface 21, spanning the entire internal space of the screen box 22 along its width. At the connection between the two side walls of the screen box 22 and the flow guide plate, reinforcing ribs are used for reinforcement. The reinforcing ribs are made of triangular or right trapezoidal metal plates, welded between the flow guide plate and the side walls to ensure that the flow guide plate will not deform or loosen when bearing the weight of the particles and the impact force of the downward slide, thus maintaining a stable flow guide effect.

[0070] The discharge port 25 is positioned near the bottom of the screen box 22, allowing polymer particles that meet the particle size requirements after being screened by the screen surface 21 to naturally fall into the area near the discharge port 25. This facilitates collection and transport to the homogenization chamber 4, reducing unnecessary accumulation and residence time of particles within the screen box 22. The rectangular shape design is well-suited for use with the inlet of subsequent conveying equipment, facilitating connection. Furthermore, it allows for control over the material's outflow speed and volume to some extent, preventing excessively fast or slow discharge from affecting the continuity of the entire production process.

[0071] The polished 25mm edge of the discharge port and the equipped flange connection structure ensure smooth material flow, preventing particle blockage or leakage caused by rough edges or loose connections. A tight connection to subsequent conveying equipment not only ensures accurate material delivery to the next stage, maintaining production continuity, but also prevents material leakage into the surrounding environment, keeping the production site clean and reducing material waste and potential safety hazards.

[0072] The guide plate is made of wear-resistant and smooth-surfaced material, which effectively reduces the friction of particles during their descent, allowing them to move smoothly and quickly to the discharge port 25. This improves discharge efficiency and reduces surface wear and debris caused by friction, ensuring product quality. The appropriate tilt angle design allows the particles to maintain a relatively stable motion while sliding down under gravity. This prevents particles from splashing and scattering at the discharge port 25 due to excessive speed, which would affect material collection and subsequent processes. It also prevents particles from accumulating on the guide plate due to an excessively small angle, which would hinder the smoothness of screening and discharge processes.

[0073] The guide plate, spanning the internal space of the screen box 22 and reinforced with reinforcing ribs, ensures its stability and reliability during the vibration and particle flow of the entire screen box 22. It uniformly receives polymer particles falling from the screen surface 21 and guides them orderly to the discharge port 25. Regardless of the vibration of the screen box 22, the guide plate will not shift or deform, ensuring stable discharge and providing strong support for the smooth completion of the entire screening process, thus improving the stability and efficiency of the entire production process.

[0074] In one feasible embodiment, the pressure roller 3 includes a roller body, which is cylindrical, with a shaft head at the center of each end of the roller body. Bearings are mounted on the shaft heads, and the roller body is rotatably mounted on the screen box 22 via the bearings. The inside of the roller body is hollow. A driving device is driven and connected to one of the shaft heads of the roller body to drive the roller body to rotate. An adsorption element 32 is disposed on the inner side wall of the roller body. When the roller body rotates, the adsorption element 32 is used to adsorb iron-containing polymer particles onto the surface of the roller body.

[0075] In this embodiment, the roller body is made of high-strength alloy steel. After a special heat treatment process, it has high hardness and good toughness, which can withstand the large pressure and friction generated during the crushing of polymer particles. This effectively prevents wear and deformation on the roller body surface, thereby ensuring the service life of the pressing roller 3 and the stability of the crushing effect.

[0076] The high-strength alloy steel roller body ensures wear resistance and stability during the crushing process, reduces wear caused by frequent contact with polymer particles, extends the service life of the pressure roller 3, and lowers equipment maintenance costs and replacement frequency. The reasonable size design allows the roller body to effectively cover the screen surface 21 area within the screen box 22, achieving comprehensive particle crushing, improving the separation efficiency of adhering particles, ensuring improved screening effect, and avoiding interference with the inner wall of the screen box 22, ensuring smooth equipment operation. The hollow structure reduces weight while providing convenient installation space for internal functional components, facilitating the integration and coordinated operation of all functions of the pressure roller 3, making the equipment structure more compact and rational.

[0077] The cylindrical roller's outer diameter is determined by the width of the screen box 22 and the effective screening area of ​​the screen surface 21, generally between 15 and 30 cm, to ensure that it can cover most of the screen surface 21 area and achieve comprehensive crushing of polymer particles. The length of the roller is slightly smaller than the width of the screen box 22 (usually with a 5-10 cm gap) to avoid interference with the inner wall of the screen box 22 during rotation, while ensuring that particles at different positions on the screen surface 21 can be crushed.

[0078] The interior of the roller is hollow. On the one hand, this reduces the weight of the entire roller and the load on the drive unit and bearings, which is conducive to the stable operation of the equipment. On the other hand, the hollow structure provides space for the installation and layout of the adsorption component 32, related cleaning devices and wiring (if any), which facilitates the rational layout and coordinated operation of the internal functional components.

[0079] The shaft ends, located at the center of both ends of the roller body, are made of high-quality medium carbon steel and precision-machined. They are connected to the roller body via an interference fit, ensuring no relative displacement during rotation and guaranteeing the integrity and stability of the roller body's rotation. The outer diameter of the shaft end is matched to the inner diameter of the selected bearing, and its surface is ground to achieve high smoothness and dimensional accuracy, reducing friction when mating with the bearing and improving rotational smoothness. Self-aligning roller bearings are selected, possessing high load-bearing capacity and excellent self-aligning performance, capable of adapting to axial and radial force changes that may occur during the operation of the pressure roller 3, effectively distributing the weight of the roller body and the force generated when crushing particles, ensuring flexible and stable roller body rotation. The bearings are installed in specially designed bearing seats on both sides of the screen box 22, and the bearing seats are firmly connected to the side walls of the screen box 22 by bolts, providing a stable support structure for the bearings. During bearing installation, strict adherence to bearing installation specifications is maintained, such as using a heat-fitting method to ensure proper and undamaged bearing installation, allowing the roller body to rotate smoothly on the screen box 22 via the bearings.

[0080] The interference fit between the shaft head and the roller body, along with high-precision machining, ensures the integrity and stability of the roller's rotation, avoiding problems such as vibration and eccentricity caused by loose connections. This ensures the uniformity and accuracy of the compaction operation, improving the compaction quality of the particles. The use of self-aligning roller bearings, properly installed in stable bearing housings, effectively bears various forces on the roller body, adapting to force changes under different working conditions. This allows for flexible and smooth roller rotation, reducing equipment failure rates, improving equipment reliability and safety, extending bearing life, and lowering maintenance costs.

[0081] The power source for the drive unit is usually a three-phase asynchronous motor, which has the advantages of simple structure, reliable operation, convenient maintenance and low cost, and can meet the needs of long-term continuous operation in industrial production environment.

[0082] To transmit the power of the motor to the roller shaft, belt drive is often used. High-strength, wear-resistant rubber belts are selected and matched with pulleys of appropriate specifications (installed on the motor output shaft and the roller shaft). The efficiency and stability of the transmission are ensured by adjusting the belt tension. Belt drive has the advantages of buffering and vibration absorption, overload protection to a certain extent, and easy installation and maintenance.

[0083] The electric motor is mounted on one side of the screen box 22 via a motor mount 23. The motor mount 23 is fixed to the screen box 22 by welding or bolting to ensure the stability of the motor's installation position. The output shaft of the motor is connected to the shaft of the roller body via a transmission component (belt or gear). Appropriate protective and positioning measures are taken at the connection point, such as using protective covers to prevent personnel from accidentally contacting rotating parts, and setting positioning pins to ensure the accuracy and stability of the connection, preventing loosening or misalignment during operation that could affect power transmission.

[0084] The speed of the pressure roller 3 is flexibly adjustable according to different polymer particle states (such as degree of adhesion, particle size, etc.) and production process requirements, and is equipped with a speed regulating device. The transmission ratio can be changed by adjusting the diameter ratio of the pulleys, thereby realizing speed regulation; the speed regulation range allows the roller speed to be flexibly varied between 30 and 200 rpm, enabling the pressure roller 3 to better adapt to various production conditions and improve the effect of crushing and separating polymer particles.

[0085] The equipped speed control device allows the pressure roller 3 to flexibly adjust its rotation speed according to different material conditions and production requirements. This enables better crushing and separation of polymer particles with varying degrees of adhesion and particle size. For example, for particles with severe adhesion, the rotation speed can be appropriately increased to enhance the crushing pressure and improve the separation efficiency of the adhered particles. Conversely, for smaller and more fragile particles, the rotation speed can be reduced to avoid excessive crushing and particle breakage, thus ensuring product quality. This also improves the equipment's adaptability to different materials and expands its application range.

[0086] The adsorption elements 32 are evenly distributed along the inner wall of the roller body in a ring arrangement, with a certain distance between adjacent electromagnets (generally between 5 and 10 cm). This ensures a relatively uniform and comprehensive magnetic field area on the roller body surface. Regardless of where the particle is on the screen surface 21 as it passes under the pressure roller 3, iron-containing impurities have a high probability of being adsorbed onto the roller body surface, improving the comprehensiveness and effectiveness of adsorption. The uniform arrangement ensures the formation of a comprehensive and stable magnetic field area on the roller body surface, improving the comprehensiveness and reliability of impurity adsorption. No matter where the particle is on the screen surface 21, iron-containing impurities can be effectively adsorbed, further enhancing the impurity removal effect.

[0087] Reference Figure 1 , Figure 2 and Figure 3 In one feasible embodiment, the adsorption element 32 is a permanent magnet, which is fixedly installed on the inner sidewall of the roller body.

[0088] In this embodiment, a neodymium iron boron permanent magnet is selected as the adsorption element 32. It has an extremely high magnetic energy product, enabling it to generate a strong magnetic field within a small volume. This allows it to adsorb iron-containing impurities from polymer particles, achieving good adsorption even for trace amounts of iron. This ensures that the permanent magnet maintains stable magnetism and its adsorption capacity for iron-containing impurities even during long-term use, despite external magnetic field interference, temperature changes, and vibrations during the rolling process.

[0089] The permanent magnet is fixed to the roller body along its inner wall using a combination of specially designed grooves and strong adhesive. Grooves matching the shape and size of the permanent magnet are pre-machined into the inner wall of the roller body. The depth of the grooves is generally about one-third to one-half the thickness of the permanent magnet. After the permanent magnet is embedded in the groove, a high-strength, heat-resistant adhesive (such as epoxy resin) with good bonding properties is filled between the groove and the permanent magnet to further reinforce the fixation of the permanent magnet and ensure that it will not loosen or shift under conditions such as roller rotation or impact from particles.

[0090] The permanent magnets are arranged in a uniform ring along the inner wall of the roller, with adjacent magnets in close contact without significant gaps, to form a continuous and uniform magnetic field region on the roller surface. Simultaneously, the number and size of the permanent magnets are rationally determined based on the length and diameter of the roller. For example, for a roller with a diameter of 20 cm and a length of 80 cm, permanent magnets with a length of 10 cm, a width of 5 cm, and a thickness of 2 cm can be selected, with 8-10 magnets evenly arranged along the circumference and 8-10 rows evenly arranged along the axial direction. This ensures a strong and uniform magnetic field coverage across the entire roller surface, improving the adsorption efficiency for iron-containing impurities.

[0091] The high energy product and strong magnetism of neodymium iron boron permanent magnets enable them to generate a strong adsorption force on iron-containing impurities during the screening of polymer particles. Even if the impurity particles are small in size or have a low content, they can be effectively adsorbed onto the roller surface, greatly improving the iron removal effect and precision. This enhances the purity of the final polymer product, ensures the quality stability of the product during subsequent processing and use, and avoids problems such as product appearance defects, decreased mechanical properties, and damage to processing equipment caused by residual iron impurities.

[0092] The high coercivity ensures the long-term stability of the permanent magnet's magnetism. During the long-term operation of the vibrating screen, in the face of frequent vibrations, different working temperature environments, and possible weak external electromagnetic interference, the permanent magnet can still stably exert its adsorption effect. Unlike electromagnets, it does not require a continuous power supply and complex magnetic field strength adjustment and control. This reduces the problem of fluctuations in adsorption effect caused by magnetic field instability, improves the reliability and predictability of the entire adsorption and impurity removal process, and reduces the complexity of equipment operation and maintenance costs.

[0093] The combination of slots and adhesive in the fixing method ensures both the secure installation of the permanent magnet and ease of operation. The slots provide initial positioning and restraint for the permanent magnet, preventing displacement in the axial and circumferential directions, while the adhesive further fills the gaps, enhancing the connection strength between the permanent magnet and the roller. This allows it to withstand the centrifugal force of the roller rotation and the impact force of particles on the roller surface, ensuring that the permanent magnet remains in the correct position throughout the entire service life of the equipment, maintaining a stable magnetic field distribution and guaranteeing the continuous effectiveness of the adsorption function.

[0094] The uniform and densely arranged permanent magnets form a comprehensive, continuous, and uniformly strong magnetic field region on the roller surface. This ensures that iron-containing impurities receive a relatively consistent adsorption force regardless of their location on the screen surface 21 as they pass under the pressure roller 3. This avoids adsorption dead zones caused by uneven magnetic field strength, improving the comprehensiveness and effectiveness of adsorption, further optimizing the iron removal effect, and ensuring consistent product quality. Simultaneously, the rational determination of the number and size of the permanent magnets allows for adaptation to the actual size and shape of the roller. This meets adsorption requirements while avoiding waste of permanent magnet material, controlling equipment costs, and making the overall roller structure more rational and compact, which is conducive to stable equipment operation and improved overall performance.

[0095] Reference Figure 1 , Figure 2 and Figure 4 In one feasible embodiment, the adsorption element 32 is an electromagnet, which is disposed in the roller body and has a gap with the inner sidewall of the roller body. The electromagnet changes the magnetic force of the electromagnet by adjusting the current supplied to the electromagnet, which is used to adjust the adsorption intensity of the pressure roller 3 according to the amount of polymer particles on the screen surface 21.

[0096] In this embodiment, the core of the electromagnet is made of electrical pure iron with high magnetic permeability, which has excellent magnetic permeability and can concentrate the magnetic field lines, enhance the magnetic field strength generated by the electromagnet, and effectively reduce hysteresis loss, improve the working efficiency of the electromagnet, and ensure that a stable and strong magnetic field can be quickly formed after current is applied, so as to better adsorb iron-containing polymer particles.

[0097] The coil is made of enameled wire with high temperature resistance and good insulation properties. The number of turns and wire diameter of the coil are determined according to the required magnetic field strength range and the power supply conditions of the equipment. By precisely controlling the winding parameters of the coil, it is ensured that the electromagnet can accurately output a magnetic field of corresponding strength under different current conditions, thus meeting the requirements for adjusting the attraction strength.

[0098] Multiple electromagnets are evenly distributed along the axial direction of the roller body inside the roller body, and are also arranged at equal intervals in the circumferential direction. An appropriate interval is maintained between adjacent electromagnets (usually between 5 and 10 cm) to ensure the formation of a uniform and widely covered magnetic field area on the roller body surface. Each electromagnet works relatively independently, but they also cooperate to provide a stable adsorption force for polymer particles passing through the entire screen surface 21 area.

[0099] A certain gap is reserved between the electromagnet and the inner wall of the roller, generally controlled at around 2-5 cm. This gap serves multiple purposes. Firstly, it facilitates heat dissipation of the electromagnet during operation, preventing heat generated by prolonged energization from accumulating inside the roller and affecting its performance and lifespan. Secondly, a suitable gap allows the magnetic field to better diffuse inside the roller and penetrate to the roller surface, forming a relatively uniform and effective adsorption magnetic field. This prevents uneven magnetic field distribution due to excessive distance or reduced adsorption effect due to excessive distance, ensuring effective adsorption of iron-containing impurities in polymer particles passing beneath the roller.

[0100] A specialized mounting bracket is installed inside the roller to maintain the electromagnets in a fixed position and ensure proper clearance between them and the roller's sidewalls. The mounting bracket is made of a non-magnetic, high-strength metal material, such as aluminum alloy, and is fixed inside the roller by welding or bolting. The electromagnets are secured to the mounting bracket via slots or bolts. During installation, positioning blocks and shims are used to precisely control the distance between the electromagnets and the roller's sidewalls, ensuring accurate positioning of each electromagnet and preventing displacement or shaking during equipment operation.

[0101] The magnetic force of an electromagnet is directly proportional to the current flowing through its coil. The current flowing through the electromagnet coil is controlled by an external adjustable power supply, thus adjusting the magnetic force. This adjustable power supply is implemented using a frequency converter. The operator sets the corresponding current value in the control system based on the amount of polymer particles on the screen surface 21 and the observed adsorption of iron impurities, thereby changing the magnetic field strength of the electromagnet. For example, when the amount of polymer particles on the screen surface 21 is large and there are many iron impurities, the current can be appropriately increased to enhance the electromagnet's adsorption strength and ensure that more iron impurities are adsorbed. Conversely, when the amount of particles is small or the impurity content is significantly reduced, the current should be decreased to avoid excessive adsorption, which would lead to unnecessary energy consumption and potential impact on equipment operation.

[0102] Using high-permeability electrical pure iron as the core enables the electromagnet to efficiently generate a strong magnetic field, enhancing its adsorption capacity for iron-containing impurities. This ensures that even tiny iron particles can be effectively captured, improving product purity. Carefully designed coil parameters allow for precise adjustment of the magnetic field strength, meeting diverse adsorption intensity requirements in different production scenarios. This enhances the equipment's adaptability to material changes while ensuring the stability and reliability of the magnetic field. This helps maintain a stable adsorption effect and reduces problems such as incomplete or excessive adsorption of impurities caused by magnetic field fluctuations.

[0103] The uniformly distributed electromagnet layout inside the roller body ensures the formation of a uniform and comprehensive magnetic field on the roller surface. No matter where the polymer particles are on the screen surface 21, passing under the pressure roller 3, iron-containing impurities can be subjected to a relatively consistent adsorption force, avoiding adsorption dead zones, improving the comprehensiveness and effectiveness of adsorption, ensuring that particles in the entire screen surface 21 area can be effectively de-ironized, improving the screening quality, and ensuring the quality stability of the final product.

[0104] The appropriate gap provides ample space for heat dissipation of the electromagnet, effectively reducing heat buildup caused by prolonged energization, extending its service life, minimizing performance degradation and malfunction risks due to overheating, and improving the reliability and stability of the equipment. Simultaneously, the suitable gap facilitates the uniform diffusion and effective penetration of the magnetic field within the roller body, optimizing the magnetic field distribution and enhancing the adsorption effect on iron-containing impurities. This makes the adsorption process more stable and efficient, further improving the accuracy and overall quality of iron removal.

[0105] Through specialized mounting brackets and precise installation positioning measures, the electromagnet is firmly fixed and accurately positioned inside the roller body. This ensures that during equipment operation, regardless of the centrifugal force generated by the roller rotation or the impact force of particles on the roller, there will be no loosening or displacement. This guarantees the stability of the magnetic field and the continuity of the adsorption effect, avoiding problems such as changes in magnetic field distribution and abnormal adsorption caused by changes in the position of the electromagnet. This provides a strong guarantee for stable adsorption and impurity removal.

[0106] By adjusting the current flowing through the electromagnet, the magnetic force intensity can be changed. This flexible adjustment method allows the pressure roller 3 to precisely adsorb polymer particles on the screen surface 21 according to their actual condition, avoiding the limitations of a fixed adsorption intensity. When dealing with materials with different iron impurity contents and particle sizes, the adsorption intensity can be adjusted as needed. This ensures that impurities are fully adsorbed, improving product quality, while also rationally controlling energy consumption, reducing production costs, and enhancing the equipment's economy and practicality, making it better adaptable to complex and changing production environments.

[0107] In one feasible embodiment, a metal detector is also included, located near the outlet of the feeding pipe 11 of the screening assembly 2. The metal detector includes an oscillator and a detection coil. The oscillator drives the detection coil to detect the amount of iron-containing impurities in the polymer particles using a high-frequency alternating magnetic field. The electromagnet adjusts the current supplied to the electromagnet based on the detection result of the metal detector.

[0108] In this embodiment, the oscillator mainly consists of an oscillation circuit composed of electronic components such as transistors (e.g., high-frequency transistors), capacitors, and inductors. To ensure the accuracy and stability of the detection, the oscillator has good frequency stability. The detection coil is usually made of multi-turn enameled wire. The enameled wire is made of a material that is resistant to high temperatures, has good insulation properties, and excellent conductivity to ensure stable operation when high-frequency alternating current passes through it, avoiding problems such as short circuits and overheating.

[0109] When a high-frequency alternating current flows from the oscillator into the detection coil, a high-frequency alternating magnetic field is generated around the coil according to the law of electromagnetic induction. This magnetic field exhibits a certain distribution pattern in space, with its intensity being stronger near the coil and gradually weakening with increasing distance. When iron impurities within the polymer particles enter this high-frequency alternating magnetic field region, the iron impurities will generate eddy currents due to electromagnetic induction. These eddy currents will then generate a new magnetic field. This new magnetic field superimposes on the original magnetic field generated by the detection coil, causing a change in the magnetic field within the circuit containing the detection coil. This, in turn, alters the voltage, current, and other electrical parameters across the coil. These changes serve as the basis for determining the presence and quantity of iron impurities.

[0110] The metal detector is mounted on the screening assembly 2 above the outlet of the feeding pipe 11, and is fixed by a special bracket. The bracket is made of high-strength metal or engineering plastic, possessing sufficient rigidity and stability to ensure that the metal detector will not shift or shake due to vibration during the operation of the vibrating screen, thus guaranteeing detection accuracy. The center of the detection coil is positioned directly opposite the screen surface 21 area below the outlet of the feeding pipe 11, allowing polymer particles flowing out of the feeding pipe 11 to pass evenly through the high-frequency alternating magnetic field area generated by the detection coil, ensuring that every polymer particle is effectively detected.

[0111] To reduce the impact of external electromagnetic interference on the metal detector's results and to prevent the magnetic field generated by the metal detector itself from interfering with other surrounding electronic equipment, an electromagnetic shield is wrapped around it. The electromagnetic shield is typically made of high-permeability, high-conductivity metals such as copper or aluminum. Through grounding or other methods, it guides external electromagnetic interference signals to the ground while preventing the internal magnetic field from leaking outwards, creating a relatively independent and stable electromagnetic environment for detection and improving the accuracy and reliability of the detection.

[0112] When the electrical parameters of the detection coil change due to iron impurities, these changing signals are first acquired by a high-precision signal acquisition circuit. This circuit uses a high-speed, high-resolution analog-to-digital converter (ADC) to convert the analog electrical signals into digital signals for subsequent precise analysis and processing. For example, it can accurately capture minute signals with voltage changes at the microvolt level, providing a reliable data basis for accurately determining the iron impurity content.

[0113] The acquired and converted digital signal is transmitted to the signal processing unit in the control system via a shielded cable. The signal processing unit has a built-in algorithm and logic program that analyzes and processes the received signal. For example, by comparing it with a preset signal threshold (which is calibrated based on a large number of experiments and actual test data, corresponding to different levels of iron impurity content), it determines the approximate content of iron impurities in the current polymer particles. Then, the analysis result is sent to the power control module of the electromagnet in the form of digital instructions.

[0114] The power control module of the electromagnet adjusts the current flowing through the electromagnet coil according to the instructions received from the signal processing unit and a pre-set correspondence. For example, if the metal detector detects a high content of iron impurities, the signal processing unit issues a high-intensity attraction command, and the power control module increases the output current to generate a stronger magnetic field, thus enhancing the attraction of iron impurities. Conversely, if a low impurity content is detected, the power control module reduces the current accordingly, decreasing the electromagnet's attraction strength. This achieves precise and flexible attraction control, avoiding energy waste and other problems caused by excessive attraction.

[0115] Through precise circuit design and component selection, the oscillator generates a stable and adjustable high-frequency oscillation signal, providing a reliable energy source for detection. This ensures that the detection coil can continuously generate a uniform and appropriately strong high-frequency alternating magnetic field, which is crucial for the accurate detection of iron impurities within polymer particles. The detection coil's rational structure and material selection enable it to operate stably under high-frequency alternating current. Furthermore, based on the characteristics of its generated magnetic field and its sensing principle for iron impurities, it can sensitively capture even trace amounts of iron impurities in the particles, greatly improving detection sensitivity and accuracy. This helps in the early detection and treatment of iron impurities, ensuring product quality.

[0116] The metal detector is installed at a suitable location near the outlet of the feeding pipe 11 and secured with a stable bracket and effective protective shielding measures. This ensures that polymer particles entering the screen surface 21 from the source can be detected promptly and accurately, avoiding the possibility of missed detection of some impurities due to uneven particle distribution on the screen surface 21. The electromagnetic shielding reduces external interference and avoids affecting other equipment, creating a favorable detection environment and further improving the reliability and accuracy of the detection results. This provides precise detection data for the entire iron removal screening process.

[0117] The high-precision signal acquisition and processing mechanism can accurately convert and analyze the weak electrical signals generated by impurities in the detection coil, and transform them into effective commands that can be used to control the electromagnet, achieving seamless integration from detection to control. This precise data processing method ensures the accuracy of judging the iron impurity content, avoids the problem of improper adjustment of adsorption intensity due to signal errors, and enables the electromagnet to accurately adjust the adsorption force according to the actual impurity situation, thereby improving the effectiveness and accuracy of iron removal.

[0118] A dynamic current adjustment mechanism based on metal detector results allows the electromagnet's adsorption intensity to adapt in real time to changes in the iron impurity content of polymer particles, achieving intelligent and automated adsorption control. On one hand, it ensures sufficient adsorption when impurity content is high, guaranteeing product purity; on the other hand, it appropriately reduces adsorption intensity when impurity content is low, saving energy and reducing equipment wear, improving the overall operating efficiency and economy of the equipment. It also ensures the efficient and stable operation of the entire iron removal screening process, enhancing the quality stability and consistency of the final product.

[0119] In one feasible embodiment, a scraper 31 is also provided on the roller body. The scraper 31 is disposed on one side of the roller body. After the roller body adsorbs iron-containing polymer particles onto the roller body surface, the polymer particles rotate with the roller body to the scraper 31 side. The scraper 31 scrapes the iron-containing polymer particles off the roller body surface and moves them to the collection device. A cleaning and blowing device is also included, disposed at the scraper 31. The cleaning and blowing device includes a nozzle facing the scraper 31, which is used to spray a high-pressure pulsed airflow onto the scraper 31 to blow the iron-containing polymer particles on the scraper 31 into the collection device.

[0120] In this embodiment, the scraper 31 is made entirely of cemented carbide, which ensures that the blade remains sharp and structurally intact during prolonged contact and friction with the roller surface and iron-containing polymer particles, effectively scraping off particles adsorbed on the roller surface. The scraper 31 is elongated, with its length matching the length of the roller, slightly shorter than the roller length to allow for 5-10 cm of installation space, and its width is typically between 3-8 cm to ensure coverage of a certain scraping area and improve scraping efficiency.

[0121] The carbide scraper 31, with its high hardness and excellent wear and corrosion resistance, can operate stably for extended periods, reducing wear and replacement frequency and lowering equipment maintenance costs. Its suitable shape and size design allow it to effectively cover a specific scraping area on the roller surface, improving the efficiency and comprehensiveness of particle removal. This ensures that no matter where particles are adsorbed on the roller surface, they can be scraped off by the scraper 31, maintaining roller surface cleanliness, preserving the electromagnet's adsorption effect, and thus guaranteeing product purity. The stable installation structure and reasonable contact angle ensure that the scraper 31 will not loosen or shift during operation, and it can contact the roller surface at the optimal angle, achieving smooth and efficient scraping operation and improving the reliability and stability of the entire adsorption and impurity removal process.

[0122] Installation Structure: On the back of the scraper 31, on the side opposite the blade, multiple mounting holes are evenly spaced along the length, one every 10-20 cm. The scraper 31 is fixed to a special mounting bracket on one side of the roller body using bolts. The mounting bracket is made of high-strength stainless steel and welded to the outer wall of the roller body. Its shape and size match the scraper 31, ensuring that the scraper 31 is stable after installation and maintains a contact angle with the roller body surface between 10° and 30°. This angle allows the scraper 31 to scrape particles more smoothly and effectively, preventing loosening or displacement and ensuring continuous and effective scraping.

[0123] When the roller rotates under the drive of the drive device, the iron-containing polymer particles adsorbed on the surface of the roller rotate with the roller. When these particles rotate with the roller to the side where the scraper 31 is located, because the scraper 31 is in close contact with the surface of the roller and the blade of the scraper 31 has a sharp edge, at the moment the particles come into contact with the scraper 31, the scraper 31, with its own hardness and fixed contact angle, overcomes the adsorption force between the particles and the roller and the cohesive force between the particles, scraping the particles off the surface of the roller and detaching them from the roller, thus preparing them for subsequent collection and processing.

[0124] As the roller continues to rotate, iron-containing polymer particles adsorbed at different positions on the roller surface are continuously brought to the scraper 31. The scraper 31 continuously scrapes off the particles, thereby achieving the cyclic cleaning of the particles on the roller surface, preventing the particles from accumulating on the roller surface, affecting the adsorption effect of the electromagnet and the normal rotation of the roller, and ensuring that the adsorption and impurity removal function of the pressure roller 3 can operate stably and efficiently.

[0125] Benefits of the scraping principle and working process: Based on its physical scraping principle, scraper 31 can directly and effectively remove iron-containing polymer particles adsorbed on the roller surface, avoiding particle accumulation on the roller and preventing excessive accumulation from affecting the magnetic field distribution of the electromagnet and the rotational balance of the roller. This ensures the normal operation of the pressure roller 3 and the continuous performance of the adsorption and impurity removal function. The continuous scraping process keeps the roller surface relatively clean, allowing the electromagnet to continuously and efficiently adsorb new iron-containing impurities, improving the equipment's ability to handle iron-containing impurities and the overall efficiency of iron removal during screening, thus contributing to the production of high-quality polymer products.

[0126] The nozzle of the cleaning device is made of high-temperature resistant and wear-resistant metal. Its internal design incorporates a special airflow channel, enabling the ejected airflow to form a high-speed, stable, and concentrated jet. The nozzle's outlet shape is generally circular or oval, with the outlet diameter determined by the required airflow intensity and coverage area, typically between 5 and 15 mm. The nozzle is mounted near the scraper 31 via an adjustable connecting bracket. This bracket allows for flexible adjustment of the nozzle's angle, height, and distance from the scraper 31, ensuring the nozzle is accurately directed towards the scraper 31, spraying airflow onto the scraper 31 and the scraped particles.

[0127] Air source and pulse generator: The air source for the cleaning device is generally provided by an air compressor. The high-pressure gas generated by the air compressor, with a pressure typically between 0.3 and 0.8 MPa, is stored and stabilized in an air tank before being delivered to the pulse generator. Based on control components such as solenoid valves, the pulse generator can convert continuous airflow into high-pressure pulsed airflow at a set frequency of 5-20 times per minute and a pulse width of 0.1-0.5 seconds. This pulsed airflow is then delivered through pipelines to the nozzles, achieving pulsed blowing off particles from the scraper 31. Compared to continuous airflow, this pulsed airflow jet method, while ensuring the blowing effect, can more effectively utilize the air source and reduce energy consumption.

[0128] The nozzle, made of special materials and with a unique internal structure, generates a high-speed, stable, and concentrated airflow, ensuring effective impact and blowing off of particles on the scraper 31. The adjustable connecting bracket allows operators to precisely adjust the nozzle's position and angle according to actual conditions, enabling it to better adapt to different working environments and particle accumulation levels, thus improving the adaptability and flexibility of the cleaning device. The air source system, composed of an air compressor and pulse generator, provides a stable high-pressure pulsed airflow. While meeting cleaning requirements, the pulsed operation mode optimizes air source utilization, reduces energy consumption, and improves equipment economy. Furthermore, measures such as pressure stabilization via the air tank ensure airflow stability, contributing to consistent cleaning results.

[0129] When the scraper 31 scrapes the iron-containing polymer particles off the roller surface and they adhere to the scraper 31, the nozzle sprays a high-pressure pulsed airflow toward the scraper 31. Under the high-speed impact, the airflow exerts a strong external force on the particles on the scraper 31, overcoming the friction between the particles and the adhesion between the particles and the scraper 31, causing the particles to quickly detach from the scraper 31 and move toward the collection device under the drive of the airflow. Because the pulsed airflow is intermittent and has a strong impact force, it can more thoroughly blow off the particles on the scraper 31, avoiding particle residue and ensuring that the scraper 31 always maintains a good working condition and continuously and effectively performs the scraping operation.

[0130] The cleaning principle of the cleaning device utilizes the powerful impact of high-pressure pulsed airflow to thoroughly blow off particles from the scraper 31 and transport them to the collection device. This avoids problems such as particle residue and secondary pollution, ensuring the cleanliness and scraping efficiency of the scraper 31. This allows the scraper 31 to continuously and efficiently perform scraping work, maintaining the smooth operation of the entire adsorption and iron removal process. Simultaneously, timely collection of particles prevents them from interfering with the screening process, further optimizing the entire screening and iron removal process, improving product quality and equipment operational stability, and ensuring continuous and efficient production.

[0131] The cleaning and blowing device works in conjunction with the scraper 31 to effectively solve the problem of particle residue and accumulation that may occur after the scraper 31 scrapes off particles, ensuring the scraping efficiency and continuity of the scraper 31. At the same time, by promptly blowing the particles to the collection device, it prevents the scraped particles from falling back onto the screen surface 21 or being re-adsorbed onto the roller surface, maintaining the cleanliness and efficiency of the entire screening and iron removal process, and further improving product quality and equipment operation stability.

[0132] In one feasible embodiment, the roller surface is provided with a serrated pattern, and the serrated pattern surface is coated with a tungsten carbide coating. The serrated pattern is used to increase the point of impact for crushing, and the tungsten carbide coating is used to increase the service life of the serrated pattern.

[0133] In this embodiment, the serrated pattern is an isosceles triangle, with a tooth height typically between 2 and 5 mm and a tooth pitch of 5 to 10 mm. This creates suitable protrusions and depressions on the roller surface, providing sufficient leverage points for crushing polymer particles. Different tooth heights and pitches can be adjusted according to the size, hardness, and adhesion of the polymer particles.

[0134] The serrated pattern is evenly distributed along the circumference and axial direction of the roller. In the circumferential direction, the pattern is arranged in a continuous ring, ensuring that each position of the roller can break up the polymer particles it passes through during rotation. In the axial direction, the pattern is arranged in parallel, so that the entire surface of the roller can participate in the particle breaking process, improving the comprehensiveness and efficiency of breaking.

[0135] Tungsten carbide coatings are mainly composed of tungsten carbide (WC) and a binder phase (such as cobalt, Co). Tungsten carbide has extremely high hardness (up to HV1800-2500) and wear resistance, making it a key component for the coating's high wear resistance. The binder phase, cobalt, binds the tungsten carbide particles together, enhancing the coating's toughness and bonding strength, allowing it to adhere better to the roller surface.

[0136] The thickness of the tungsten carbide coating is generally between 0.1 and 0.5 mm, with the specific thickness determined based on the working conditions and service life requirements of the roller. This coating has good wear resistance, corrosion resistance, and impact resistance, and can withstand the friction, impact, and wear of particles on the roller surface during crushing, effectively protecting the serrated texture and extending its service life.

[0137] The rationally designed serrated pattern, with its appropriate tooth height and pitch, provides multiple points of contact for crushing polymer particles. As the roller rotates, these serrations better embed into the adhered particles, increasing the crushing force and making the particles easier to separate, thus improving crushing efficiency. The evenly distributed pattern ensures that the entire roller surface participates in the crushing process, avoiding excessive wear or insufficient crushing in localized areas, and guaranteeing consistent and stable crushing results.

[0138] The high hardness and wear resistance of the tungsten carbide coating effectively protect the serrated texture, making it less prone to wear during long-term crushing operations, extending the service life of the roller, reducing the frequency of equipment maintenance and replacement, and lowering production costs. The coating's corrosion resistance and impact resistance also improve the roller's adaptability to harsh working environments, ensuring stable equipment operation.

[0139] In one feasible embodiment, an air-cooling device is also included, disposed at the outlet of the feeding pipe 11, which includes an air outlet facing the screen surface 21, for blowing air onto the polymer particles on the screen surface 21 to reduce the temperature of the polymer particles.

[0140] In this embodiment, the air-cooling device includes a fan, specifically a centrifugal fan as the power source. Centrifugal fans offer advantages such as large air volume, high air pressure, and stable operation, meeting the need for a continuous supply of large amounts of cool air to the polymer particles on the screen surface 21. The air outlet adopts a trumpet-shaped design, with its larger end facing the screen surface 21 and its smaller end connected to the air duct. This trumpet-shaped structure allows the blown airflow to diffuse at the outlet, increasing the area covered by the airflow and ensuring that it can be evenly blown onto the polymer particles at different positions on the screen surface 21. The air duct is typically made of galvanized steel sheet with a smooth interior to reduce airflow resistance during transport. The shape of the air duct is rationally designed according to the equipment layout and space, and can be combined with various forms such as straight pipes and curved pipes to ensure that the airflow generated by the fan is smoothly guided to the air outlet.

[0141] The air-cooling unit is equipped with corresponding adjustment devices to flexibly control parameters such as air velocity, air volume, and air direction according to different production conditions. An air volume regulating valve is installed on the air duct. By manually or electrically rotating the regulating handle or controlling the motor 23, the valve opening can be changed, thereby achieving linear adjustment of the air volume within the range of 0-100%. Simultaneously, the air outlet is connected to the support frame via a movable connecting structure, allowing adjustment of the outlet's orientation within a certain angle range to precisely control the air direction and better align it with the screen surface 21 and the area where the polymer particles are located.

[0142] After the fan starts, motor 23 drives the impeller to rotate at high speed, drawing the surrounding air into the fan. Under the action of the impeller, the air gains energy and is accelerated, forming an airflow with a certain pressure and velocity. Since the ambient temperature is relatively low (usually lower than the temperature of the polymer particles), the drawn-in air is equivalent to cold air, and the fan delivers this cold air to the outlet through the duct.

[0143] Cold air blown from the outlet is directed at a certain speed and angle towards the polymer particles on the screen surface 21. The cold air comes into full contact with the particles, and heat exchange carries away the heat from the particles, causing the particle temperature to gradually decrease. During this process, parameters such as air volume, air speed, and air direction can be adjusted reasonably by the regulating device according to factors such as the initial temperature and quantity of the particles and the desired cooling target. This ensures that the particles can be uniformly cooled to a suitable temperature range in a short time, avoiding adverse effects on subsequent screening, iron removal, and product quality due to excessively high temperatures.

[0144] The selection of a centrifugal fan, along with a suitable impeller material and motor 23, ensures stable and efficient fan operation, generating sufficient airflow and pressure to provide reliable power for delivering cool air to the screen surface 21. A large airflow ensures sufficient cool air for heat exchange with the polymer particles, while appropriate air pressure enables the airflow to overcome resistance from the ductwork and screen surface 21, accurately delivering cool air to the location of the particles, thus achieving an effective cooling effect.

[0145] The trumpet-shaped air outlet design increases the airflow coverage area, allowing the polymer particles on the screen surface 21 to be more evenly exposed to the cool air. This prevents localized over- or under-cooling, ensuring uniform and consistent cooling, which helps improve product quality stability. The smooth air duct reduces airflow resistance, improves fan efficiency, reduces energy consumption, and also reduces noise caused by airflow turbulence, improving the working environment.

[0146] Equipped with an airflow regulating valve and an adjustable air outlet angle, the air-cooling unit can flexibly adjust parameters according to different production scenarios, adapting to cooling needs under various conditions. For example, when the polymer particle output is large and the temperature is high, the airflow can be increased and the airflow direction adjusted to enhance the cooling effect; while when the particle temperature is relatively low or the cooling accuracy requirement is high, the airflow and airflow direction can be finely adjusted to achieve precise cooling, improving the adaptability and controllability of the equipment and ensuring that the cooling process always meets production requirements.

[0147] Air cooling allows polymer particles to cool evenly on the sieve surface 21, preventing problems such as increased particle adhesion and decreased flowability caused by excessive temperature. This facilitates subsequent screening, crushing, and other processes, improving the efficiency and quality of each step. Furthermore, a proper cooling process prevents changes in particle properties due to overheating (such as thermal degradation), ensuring the quality of the final product and extending its lifespan. This is crucial for the stability of the entire production process and the improvement of product quality.

[0148] Although the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the present invention to these descriptions. Those skilled in the art can make various changes in form and detail, including some simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A vibrating screen for screening polymer particles cut by a pelletizer, characterized in that, include: The feeding assembly includes a feeding pipe through which polymer particles cut by the pelletizer are conveyed; A screening component is provided at the outlet of the feeding pipe. The screening component includes a screen surface, and polymer particles flow into the screen surface through the feeding pipe. A pressing roller is rotatably connected to the screening assembly and is positioned above the screen surface with a gap between it and the screen surface. An adsorption element is provided inside the pressing roller. When the screening component screens polymer particles, the pressure roller can roll and crush the polymer particles to separate the adhering polymer particles, and the adsorption element is used to adsorb polymer particles containing iron impurities.

2. The vibrating screen as described in claim 1, characterized in that, The filtering component also includes: A sieve box with an opening at the top, the interior of which is a cavity for receiving polymer particles, and the sieve surface is disposed at the opening at the top of the sieve box and fixedly connected to the sieve box; A motor is located on one side of the screen box. The motor is connected to the screen box via a spring bracket. An eccentric block is provided on the drive shaft of the motor. The eccentric block is connected to the spring bracket. When the motor drives the eccentric block to rotate, the eccentric block drives the spring bracket connected to it and the screen box connected to the spring bracket to reciprocate.

3. The vibrating screen as described in claim 2, characterized in that, The screening assembly also includes two guide plates, which are thin metal plates disposed on the screen surface and arranged on both sides of the screen surface along the reciprocating vibration direction of the screen box. They are used to change the movement trajectory and speed of polymer particles and prevent polymer particles from accumulating.

4. The vibrating screen as described in claim 2, characterized in that, The screen box also includes a discharge port, which is located on the side of the screen box near the bottom. The screen box is provided with a guide plate that is inclined toward the discharge port. The polymer particles move along the guide plate to the discharge port and flow into the next process through the discharge port.

5. The vibrating screen as described in claim 2, characterized in that, The pressure roller includes: The roller body is cylindrical, with a shaft head at the center of each end of the roller body. Bearings are mounted on the shaft heads, and the roller body is rotatably mounted on the screen box via the bearings. The inside of the roller body is hollow. A drive unit is connected to one of the shaft heads of the roller body to drive the roller body to rotate. An adsorption element is disposed on the inner side wall of the roller body. When the roller body rotates, the adsorption element is used to adsorb iron-containing polymer particles onto the surface of the roller body.

6. The vibrating screen as described in claim 5, characterized in that, The adsorption element is a permanent magnet, which is fixedly installed on the inner sidewall of the roller body.

7. The vibrating screen as described in claim 5, characterized in that, The adsorption element is an electromagnet, which is disposed in the roller body and has a gap with the inner sidewall of the roller body. The electromagnet changes the magnetic force by adjusting the current flowing into it, and is used to adjust the adsorption intensity of the pressure roller according to the amount of polymer particles on the screen surface.

8. The vibrating screen as described in claim 7, characterized in that, It also includes a metal detector, which is located near the outlet of the feeding pipe of the screening assembly. The metal detector includes an oscillator and a detection coil. The oscillator drives the detection coil to detect the amount of iron impurities in the polymer particles using a high-frequency alternating magnetic field. The electromagnet adjusts the current supplied to the electromagnet according to the detection result of the metal detector.

9. The vibrating screen as described in claim 5, characterized in that, The roller is also equipped with a scraper, which is located on one side of the roller. When the roller adsorbs iron-containing polymer particles onto its surface, the polymer particles rotate with the roller to the scraper side. The scraper scrapes the iron-containing polymer particles off the roller surface and moves them to the collection device.

10. The vibrating screen as described in claim 9, characterized in that, It also includes a cleaning and blowing device disposed at the scraper. The cleaning and blowing device includes a nozzle facing the scraper and is used to spray a high-pressure pulsed airflow onto the scraper to blow the iron-containing polymer particles on the scraper into the collection device.

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