A powder screening device for drug production

Abstract

This application provides a powder screening device for pharmaceutical production, belonging to the field of pharmaceutical production technology. It includes a frame and a screening chamber located at the upper end of the frame. A feeding chamber is located at the right end of the screening chamber. A screen is rotatably connected inside the screening chamber, and a main shaft is rotatably connected inside the feeding chamber, with the main shaft and screen coaxially arranged. A bushing is fixedly installed on the outer side of the main shaft, and sleeves are arranged in a circumferential array on the outer side of the bushing. The outer sides of the sleeves corresponding axially are fixedly connected to impeller blades. Sealing plates are slidably connected within the sliding grooves opened inside the impeller blades. Air grooves corresponding to the screen positions are opened on the sides of the sealing plates. The sliding grooves are connected to a through hole in the middle of the main shaft via air pipes. This application effectively solves the problem of screen clogging caused by electrostatic adsorption and slight agglomeration of viscous materials, while simultaneously achieving high-pressure airflow purging and mechanical scraping, combined with screen rotation to complete all-round cleaning.

Description

Technical Field

[0001] This application relates to the field of pharmaceutical manufacturing technology, specifically to a powder screening device for pharmaceutical manufacturing. Background Technology

[0002] Pharmaceutical powders, as core intermediate or end products in the pharmaceutical industry, are often used in the production of various pharmaceutical products such as oral preparations, external powders, and sterile powders for injection. The uniformity of particle size distribution, purity, and flowability of the powder directly affect the dissolution rate, bioavailability, and clinical efficacy of the drugs. In the pharmaceutical powder production process, sieving is a key refining step, which requires classifying the pulverized powder according to a preset particle size to remove impurities and oversized particles, ensuring that the product quality meets pharmacopoeia standards. With the continuous improvement of the pharmaceutical industry's requirements for product precision, efficient and stable sieving technology has become a core link that urgently needs to be optimized in the pharmaceutical powder production process.

[0003] Currently, commonly used screening devices in pharmaceutical powder production mainly include vibrating screens, rotary vibrating screens, and air classifiers. Among them, vibrating screens and rotary vibrating screens use vibrators to generate high-frequency vibrations to classify materials. However, for fine-particle-size pharmaceutical powders (especially ultrafine powders with a particle size of less than 100μm), the inertial force generated by vibration can easily cause the powder to agglomerate, which not only reduces the screen penetration rate but also makes it easy for fine powder to adhere to the screen surface and form blockages. Air classifiers use airflow to drive the material to move and pass through the screen. Although this reduces agglomeration to some extent, when the pharmaceutical powder contains trace amounts of sticky components (such as traditional Chinese medicine extract powders or wet powders), the material is easy to embed into the screen mesh or form scale on the screen surface, resulting in a continuous decrease in screening efficiency. This requires frequent shutdowns for cleaning, affecting the continuity of production.

[0004] To address the problem of screen clogging in screening devices, relevant technical fields have proposed targeted improvement solutions. For example, Chinese patent document CN119857645B discloses a sliding cleaning airflow screen and its unclogging structure. This device includes a screen cage, a stirring assembly, and a blowing assembly. The stirring assembly is located inside the screen cage, and the blowing assembly is located at one end of the screen cage. By mounting a gravity sensor on a fixed frame to monitor changes in material weight, the screen clogging status is determined. When the detected value exceeds a threshold, the gap and tilt angle between the impeller blades and the screen are adjusted via an electric telescopic rod. The scraping action of the impeller blades combined with the pulse blowing of the blowing assembly achieves coordinated screening and unclogging operations, thereby improving the screen permeability to a certain extent.

[0005] However, while the aforementioned technical solutions can alleviate screen clogging to some extent in pharmaceutical powder sieving scenarios, they cannot completely eliminate the clogging phenomenon. Compared to ordinary industrial materials, pharmaceutical powders have characteristics such as finer particle size, larger specific surface area, easy moisture absorption and agglomeration, and some varieties are inherently sticky. Although scraping and cleaning by the contact between the impeller blades and the screen can remove the material attached to the screen surface, for ultra-fine sticky pharmaceutical powder particles embedded in the screen aperture, the scraping force is difficult to accurately transmit to the inside of the mesh, which can easily lead to particle residue and gradual accumulation to form stubborn blockage. Moreover, the contact scraping between the impeller blades and the screen may cause mechanical wear on the screen, especially for high-precision fine-pore screens commonly used in pharmaceutical powder sieving. After wear, the aperture will become larger, which will affect the sieving accuracy of pharmaceutical powder. On the other hand, reducing the scraping force cannot effectively remove sticky blockages, creating a contradiction between the clogging removal effect and screen protection. Ultimately, this leads to the recurrence of screen clogging problems, which restricts the stability and efficiency of pharmaceutical powder sieving. Summary of the Invention

[0006] In view of this, this application provides a powder screening device for pharmaceutical production, which solves the problem of screen blockage caused by powder material embedding inside the screen.

[0007] To solve the above-mentioned technical problems, this application provides a powder screening device for pharmaceutical production, including a frame and a screening chamber disposed on the upper end of the frame. A feeding chamber is disposed on the right end of the screening chamber. A screen is rotatably connected inside the screening chamber. A main shaft is rotatably connected inside the feeding chamber, and the main shaft is coaxially arranged with the screen. A bushing is fixedly installed on the outer side of the main shaft. Sleeves are arranged in a circumferential array on the outer side of the bushing. The outer sides of the sleeves corresponding to the axial direction are fixedly connected to impeller blades. A sealing plate is slidably connected in a sliding groove opened inside the impeller blade. An air groove corresponding to the position of the screen is opened on the side of the sealing plate. Air holes for connecting the air grooves and sliding grooves are evenly opened inside the sealing plate. The sliding groove is connected to a through hole in the middle of the main shaft through an air pipe.

[0008] By adopting the above technical solution, the main shaft drives the impeller blades to rotate, which in turn drives the airflow in the screening chamber to form a spiral vortex. The radial centrifugal force and axial propulsion force generated by the vortex can break up the agglomeration of drug powder and drive the material to adhere to the screen, providing power for efficient screening and improving the screening accuracy of fine powder. During screen cleaning, high-pressure gas is precisely introduced into the air groove corresponding to the screen through the through hole in the middle of the main shaft, the air pipe, the slide groove of the impeller blade, and the air hole of the sealing plate. It targets the powder adsorbed on the inner wall of the screen and, together with the extended sealing plate, can effectively clean the material agglomerated on the inner wall of the screen. Moreover, the hidden air path design completely isolates the air path from the screening area, which not only prevents drug powder from entering the air path and causing blockage and contamination, ensuring the stability of the screen cleaning effect, but also prevents impurities in the air path from mixing into the material and affecting the purity of the drug. This meets the stringent cleanliness requirements of drug production and ultimately achieves a triple optimization of screening efficiency, screen cleaning effect, and material cleanliness.

[0009] Optionally, each sleeve has a T-shaped rod slidably connected inside. The outer ends of the T-shaped rods are fixedly connected to the corresponding sealing plates in the axial direction. Each T-shaped rod is fitted with a spring. The spring applies a driving force to the T-shaped rod to move it closer to the main shaft and allows the sealing plate to be completely hidden in the groove inside the wind turbine blade.

[0010] By adopting the above technical solution, the sealing plate is automatically reset and hidden by the elastic force of the spring. During the sieving process, the sealing plate is completely stored in the chute, which will not interfere with the airflow driven by the impeller blades and the sieving trajectory of the drug powder. This avoids powder agglomeration or loss caused by ineffective collision between the sealing plate and the drug powder, simplifies the device structure and reduces energy consumption. At the same time, it provides guidance for the subsequent sliding of the sealing plate and adapts to the needs of continuous operation in drug production.

[0011] Optionally, the outer side of the sealing plate is threaded with an adjusting stud, and the outer side of the wind turbine blade is provided with a stepped hole that seals with the adjusting stud.

[0012] By adopting the above technical solution, the maximum extension distance of the sealing plate can be precisely limited by adjusting the fit between the stud and the stepped hole. This ensures that the sealing plate maintains a reasonable distance from the screen during screen cleaning, avoiding screen wear and drug powder contamination caused by hard contact. It can also adapt to the screen cleaning needs of drug powders with different particle sizes. By rotating the stud to change the distance, targeted cleaning of powders with different degrees of agglomeration adhering to the inner wall of the screen can be achieved. At the same time, the threaded connection and sealing fit design can prevent drug powder from entering the stepped hole or chute during the screening process, ensuring the sealing performance and operational stability of the device.

[0013] Optionally, a drive ring is rotatably connected inside the screening chamber. The inner arc surface of the drive ring is uniformly provided with arc-shaped grooves. Arc-shaped strips that cooperate with the arc-shaped grooves are uniformly provided at the outer end of the screen. The frame is provided with a drive assembly for driving the drive ring to rotate.

[0014] By adopting the above technical solution, and through the interlocking of arc grooves and arc strips, a stable linkage between the drive ring and the screen is achieved. When the drive component drives the drive ring to rotate, it can synchronously drive the screen to rotate. Moreover, the interlocking structure facilitates the disassembly and maintenance of the screen, and is suitable for the replacement needs of screens of different specifications in drug production. At the same time, the circumferentially evenly distributed arc grooves and arc strips can make the screen bear the force evenly, avoid the screen from shifting or shaking when rotating, ensure the stability of the drug powder sieving trajectory, and improve the sieving accuracy.

[0015] Optionally, the bottom of the screening chamber is provided with a fine material outlet and a coarse material outlet, and the end of the screen near the coarse material outlet is provided with an impeller for pushing the coarse material to the coarse material outlet, and the middle part of the impeller is rotatably connected to the main shaft, and the impeller is located between the fine material outlet and the coarse material outlet.

[0016] By adopting the above technical solution, the graded collection and precise conveying of coarse and fine materials can be achieved. After being screened by the screen, the fine material is discharged from the fine material outlet, while the coarse material moves towards the coarse material outlet under the action of airflow and spiral propulsion. The impeller can actively push the coarse material gathered at the end of the screen to the coarse material outlet, avoiding the accumulation of coarse material that blocks the end of the screen and affects the screening efficiency. At the same time, the impeller is located between the two outlets, which can effectively separate the conveying paths of coarse and fine materials, prevent fine material from mixing into coarse material and causing a decrease in screening accuracy, and reduce material waste.

[0017] Optionally, the outer arc surface of the screening chamber is evenly distributed with nozzles corresponding to the positions of the screen, and each nozzle is connected to an external high-pressure air source.

[0018] By adopting the above technical solution, the nozzles spray high-pressure air from the outside of the screen and, in conjunction with the rotation of the screen, can completely remove the drug powder adsorbed in the screen holes, greatly reducing the probability of screen clogging. The circumferentially distributed nozzles can ensure that the cleaning range covers the entire circumference of the screen, so that the force on each area of ​​the screen is uniform and avoids excessive local air pressure that could cause screen deformation.

[0019] Optionally, a cover is fixedly installed on the side of the screening chamber near the coarse material outlet, the left end of the main shaft is movably inserted into the inside of the cover, and an air connector for supplying air to the inside of the main shaft is provided on the outside of the cover.

[0020] By adopting the above technical solution, the cover can seal the end of the screening chamber to prevent drug powder from leaking during the screening process, ensuring a clean production environment and the health of operators; the movable plug-in fit between the main shaft and the cover does not affect the high-speed rotation of the main shaft, and can provide a stable channel for the gas connector to supply gas, so that high-pressure gas can be accurately delivered into the main shaft through hole through the gas connector, realizing that the gas circuit and the transmission structure do not interfere with each other, and improving the stability and reliability of the device operation.

[0021] Optionally, the drive assembly includes a motor disposed on the outside of the frame, and a rotating shaft is rotatably connected inside the screening chamber. One end of the rotating shaft is provided with a gear, and the gear meshes with teeth evenly distributed on the outer arc surface of the drive ring. The motor can drive the rotating shaft to rotate by belt drive.

[0022] By adopting the above technical solution and using a motor drive, the rotation direction and speed of the screen can be precisely controlled. Through the meshing of gears and drive rings, the rotation of the shaft is converted into the stable rotation of the screen. Moreover, the diameter of the gears is smaller than the diameter of the drive rings, which allows the screen to rotate slowly in the opposite direction, thus meeting the requirements for fine sieving of drug powders.

[0023] Optionally, the right end of the main shaft is rotatably connected to the inner wall of the feeding hopper, and a spiral blade for feeding is provided at the right end of the main shaft. The spiral blade is located inside the feeding hopper, and the motor can drive the main shaft to rotate through belt drive.

[0024] By adopting the above technical solution, continuous and uniform feeding of drug powder can be achieved. When the spiral blade rotates with the main shaft, it can smoothly push the powder in the feeding hopper into the screening hopper, avoiding the screening blockage caused by the accumulation of powder at the feeding port. At the same time, the spiral feeding can control the feeding speed, so that the powder enters the screening area with a uniform thickness, improves the screening accuracy, simplifies the device structure, reduces the number of power sources, reduces the equipment manufacturing cost and maintenance difficulty, and is suitable for continuous operation scenarios in drug production.

[0025] Optionally, the outer arc surface of the screening chamber is provided with an observation window.

[0026] By adopting the above technical solution, operators can observe the sieving status of drug powder, material accumulation, and screen cleanliness in the sieving chamber in real time through the observation window. This facilitates timely detection of sieving abnormalities and the implementation of countermeasures to prevent the malfunction from escalating and affecting production efficiency.

[0027] In summary, compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0028] 1. By using the relative motion of the impeller blades and the screen rotating in opposite directions, combined with the reverse air jet from the external air source, the problem of screen sticking and clogging caused by electrostatic adsorption and slight agglomeration of sticky materials can be solved. At the same time, the external air source jets air onto the outer side of the screen through the nozzle, which creates a backflow effect on the screen, further avoiding the risk of clogging. It can also promote the uniform contact of materials with the entire circumference of the screen, effectively improving the screening rate and fine powder recovery rate.

[0029] 2. It adopts a pneumatically driven concealed sealing plate structure. The sealing plate is hidden during screening and does not interfere with the operation. During cleaning, high-pressure airflow and mechanical scraping can be achieved simultaneously, and the screen rotation can complete all-round cleaning. At the same time, the distance between the sealing plate and the screen is controlled by an adjustable limit structure, which avoids mechanical wear while cleaning the screen efficiently and reduces the probability of screen failure.

[0030] 3. The initial separation of coarse and fine materials is achieved by relying on the bidirectional force of the spiral swirling flow field. Combined with the obstruction of the impeller, the coarse material is intercepted and screened for a second time, which greatly reduces the loss of fine material discharged with the coarse material. Through the dual transmission path design of motor linkage, the main shaft and screen rotate in opposite directions at different speeds, providing stable power support for efficient screening, anti-clogging and cleaning. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a powder screening device for drug production according to this application; Figure 2This is a schematic diagram of the front structure of this application; Figure 3 This is a schematic diagram of the internal front sectional structure of this application; Figure 4 For this application Figure 3 A magnified schematic diagram of the structure at point A; Figure 5 For this application Figure 3 A magnified schematic diagram of the structure at point B; Figure 6 This is a schematic diagram of the left sectional view of the structure of this application; Figure 7 For this application Figure 6 A magnified schematic diagram of the structure at point C; Figure 8 This is a partial cross-sectional view of the drive ring structure of this application.

[0032] Explanation of reference numerals in the attached drawings: 1. Frame; 101. Screening bin; 102. Feed bin; 103. Fine material outlet; 104. Coarse material outlet; 105. Nozzle; 106. Observation window; 2. Main shaft; 21. Bushing; 22. Sleeve; 23. Wind turbine blade; 231. Slide groove; 24. Air pipe; 25. T-shaped rod; 26. Spring; 27. Spiral blade; 3. Screen; 31. Arc-shaped strip; 32. Impeller; 4. Sealing plate; 41. Air groove; 42. Air hole; 5. Adjusting stud; 6. Stepped hole; 7. Drive ring; 71. Arc-shaped groove; 8. Drive assembly; 81. Motor; 82. Rotating shaft; 821. Gear; 9. Cover; 91. Air connector. Detailed Implementation

[0033] The following will be described in conjunction with embodiments of this application. Figures 1-8 The technical solutions of the embodiments of this application are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of this application are within the scope of protection of this application.

[0034] Reference Figure 1 , Figure 2 and Figure 3This embodiment provides a powder screening device for pharmaceutical production, including a frame 1, a screening mechanism, and a blockage removal mechanism. The frame 1 is welded from square tubing, and a screening chamber 101 is fixedly installed at the upper end of the frame 1. The bottom of the screening chamber 101 is provided with a fine material outlet 103 and a coarse material outlet 104. The screening mechanism is installed inside the screening chamber 101, and the screening mechanism is positioned corresponding to the fine material outlet 103, so that the screened fine material can be discharged through the fine material outlet 103 at the bottom of the screening chamber 101. The tail end of the screening mechanism is positioned corresponding to the coarse material outlet 104, so that the coarse material remaining after screening can be discharged through the coarse material outlet 104 at the bottom of the screening chamber 101.

[0035] The screening chamber 101 is rotatably connected to a main shaft 2. The right end of the main shaft 2 is located in the feed chamber 102 located at the right end of the screening chamber 101. The right end of the main shaft 2 is provided with a spiral blade 27, which is located inside the feed chamber 102. The unblocking mechanism is arranged in a circumferential array on the outside of the main shaft 2, and the unblocking mechanism is located inside the screening mechanism.

[0036] In use, the material to be screened is fed into the feed hopper 102, and then the main shaft 2 rotates, causing the spiral blade 27 on the right side of the main shaft 2 to rotate, pushing the material inside the feed hopper 102 into the screening mechanism. When the material passes through the screening mechanism, the fine material screened out is discharged from the fine material outlet 103 at the bottom of the screening hopper 101, while the coarse material remaining after screening is discharged from the coarse material outlet 104 at the bottom of the screening hopper 101.

[0037] Reference Figure 3 and Figure 6 The screening mechanism includes a screen 3 and a drive ring 7; both the screen 3 and the drive ring 7 rotate inside the screening chamber 101. The inner arc surface of the drive ring 7 is uniformly provided with arc-shaped grooves 71, and the outer end of the screen 3 is uniformly provided with arc-shaped strips 31 that mate with the arc-shaped grooves 71 (see reference). Figure 8 A bushing 21 is fixedly installed on the outer side of the main shaft 2, and sleeves 22 are arranged in a circumferential array on the outer side of the bushing 21. The outer side of the sleeves 22 corresponding to the axial direction is fixedly connected to the wind turbine blades 23. The drive assembly 8 installed inside the frame 1 can drive the drive ring 7 and the main shaft 2 to rotate in opposite directions through belt drive. The outer arc surface of the screening chamber 101 is evenly distributed with nozzles 105 corresponding to the positions of the screen 3. The nozzles 105 are all connected to the external high-pressure air source.

[0038] When screening materials, the drive assembly 8 drives the main shaft 2 to rotate, causing the impeller blades 23, which are fixedly installed on the outside of the main shaft 2 through the bushing 21 and the sleeve 22, to rotate inside the screen 3. The high-speed rotation of the impeller blades 23 drives the airflow inside the screen 3 to form a spiral vortex. In the vortex, the material is simultaneously subjected to radial centrifugal force (driving the material to stick to the screen 3) and axial spiral propulsion force (driving the coarse material to move to the tail end). Fine powder passes through the screen 3 by centrifugal force and air kinetic energy, while coarse material moves along the inner wall of the screen 3 to the tail end for discharge by spiral propulsion force, thus achieving efficient separation of coarse and fine materials.

[0039] Meanwhile, driven by the drive component 8, the arc groove 71 on the inner wall of the drive ring 7 cooperates with the corresponding arc strip 31 on the outer side of the screen 3, causing the screen 3 to rotate slowly in the opposite direction relative to the impeller blades 23. The relative motion between the screen 3 and the impeller blades 23 enhances the screening effect and reduces the probability of material sticking to the screen and clogging due to electrostatic adsorption and slight stickiness. The external air source sprays air onto the outer side of the screen 3 through the nozzle 105, which can have a backwashing effect on the screen 3, further reducing the probability of screen clogging. At the same time, it allows the material to contact the entire circumference of the screen 3 evenly, improving the screening rate and fine powder recovery rate.

[0040] Reference Figure 3 and Figure 4 The unblocking mechanism includes a sealing plate 4, a T-shaped rod 25, and an air pipe 24. The sealing plate 4 is slidably installed in a groove 231 provided on the outside of the impeller blade 23. Air grooves 41 corresponding to the positions of the screen 3 are opened on the sides of the sealing plate 4. Air holes 42 are evenly opened inside the sealing plate 4 to connect the air grooves 41 and the groove 231 (see reference). Figure 6 and Figure 7 The T-shaped rod 25 is slidably installed inside the sleeve 22. The outer end of the T-shaped rod 25 passes through the side wall of the impeller blade 23 and is fixedly connected to the corresponding sealing plate 4. The outer side of the T-shaped rod 25 is fitted with a spring 26. The spring 26 can apply a driving force to the T-shaped rod 25 to move closer to the main shaft 2, and make the sealing plate 4 completely hidden in the groove 231 inside the impeller blade 23. The air pipe 24 is used to connect the groove 231 with the through hole in the middle of the main shaft 2. The screening chamber 101 is fixedly installed with a cover 9 on the side near the coarse material outlet 104. The left end of the main shaft 2 is movably inserted into the inside of the cover 9. The outer side of the cover 9 is provided with an air connector 91 for supplying air to the inside of the main shaft 2.

[0041] During screening, under the elastic force of spring 26, a driving force is applied to T-shaped rod 25 to move it closer to main shaft 2, so that sealing plate 4 can be completely hidden in the groove 231 inside impeller blade 23, and the end face of sealing plate 4 is flush with the outer end face of blade to avoid interference with screening operation. At this time, main shaft 2 drives impeller blade 23 to rotate synchronously, and centrifugal force drives the material inside screen 3 to tumble and flow. Qualified particle size material passes through screen 3 to complete classification, and unqualified material is retained to ensure efficient screening. When screen 3 becomes clogged and material residue needs to be cleaned, external air source is activated. High pressure gas is injected into the through hole in the middle of main shaft 2 through air connector 91 and cavity inside sealing cover 9, and then distributed to the groove 231 of each impeller blade 23 through air pipe 24. Because the sealing plate 4 is initially hidden, its outer air groove 41 is tightly fitted with the inner wall of the slide 231 to form a closed cavity. After the air pressure continues to rise, it overcomes the elastic force of the spring 26 and pushes the sealing plate 4 to slide out along the slide 231 and close to the screen 3. At the same time, the air groove 41 and the inner wall of the slide 231 are separated, forming a smooth airflow channel. High-pressure gas is sprayed through the air groove 41 to impact the screen 3. With the slow rotation of the screen 3, it fully covers all areas of the screen 3, achieving thorough cleaning and quickly restoring the screening accuracy.

[0042] Reference Figure 3 and Figure 5 The outer side of the sealing plate 4 is threaded with adjusting studs 5, and the outer side of the impeller blades 23 is provided with stepped holes 6 that are sealed to the adjusting studs 5.

[0043] As the sealing plate 4 slides outward along the slide groove 231, the adjusting stud 5 connected to its outer thread will precisely match the pre-set stepped hole 6 on the outer side of the impeller blade 23, thus forming a reliable limiting structure to constrain the maximum movement position of the sealing plate 4. By adjusting the contact between the stud 5 and the inner wall of the stepped hole 6, it can be ensured that the sealing plate 4 can accurately approach the screen 3 while maintaining a reasonable distance. This can not only thoroughly scrape and clean the larger material agglomerates adhering to and accumulating on the inner wall of the screen 3, effectively breaking up the agglomeration and blockage problem, and ensuring the smoothness and efficiency of the screening operation, but also fundamentally avoid direct hard contact between the sealing plate 4 and the screen 3. Since the screen 3 is a precision and easily damaged component, hard contact can easily cause mechanical damage such as screen surface damage and aperture deformation. This design greatly reduces the probability of the screen 3 failing prematurely due to wear, extends the service life of the screen 3, and reduces the frequency of equipment downtime for replacement. In addition, operators can flexibly adjust the initial distance between the adjusting stud 5 and the inner step surface of the stepped hole 6 by rotating the adjusting stud 5 in the forward or reverse direction, thereby achieving precise control of the maximum displacement position of the sealing plate 4. This can adapt to the screening requirements of materials with different particle sizes, different specifications of screen parameters 3 and various working conditions, greatly improving the adaptability and flexibility of the device.

[0044] Reference Figure 2 and Figure 3The screen 3 is provided with an impeller 32 at one end near the coarse material outlet 104 for pushing the coarse material to the coarse material outlet 104. The middle part of the impeller 32 is rotatably connected to the main shaft 2 and is used to support the impeller 32 and the screen 3. The impeller 32 is located between the fine material outlet 103 and the coarse material outlet 104.

[0045] During screening, under the action of airflow, the coarse material moves to the left end of the screen 3. At this time, the impeller 32 can block the coarse material, so that the material can be screened again, greatly reducing the probability of fine material being discharged from the coarse material outlet 104. As the screen 3 rotates, the impeller 32 discharges the coarse material gathered at the left end of the screen 3, so that the screened coarse material is discharged from the coarse material outlet 104.

[0046] Reference Figure 1 and Figure 2 The drive assembly 8 includes a motor 81 and a rotating shaft 82. The motor 81 is located on the outside of the frame 1, and the rotating shaft 82 is rotatably connected to the inside of the screening chamber 101. A gear 821 is fixedly installed at one end of the rotating shaft 82. The outer arc surface of the drive ring 7 is arrayed with teeth that can mesh with the gear 821. The motor 81 can drive the rotating shaft 82 to rotate through belt drive.

[0047] During screening, the motor 81 is started, which drives the rotating shaft 82 to rotate via belt drive. In turn, the meshing of the gear 821 drives the drive ring 7 and the screen 3 to rotate in the opposite direction relative to the output shaft of the motor 81. Since the diameter of the gear 821 is smaller than the diameter of the drive ring 7, the screen 3 can rotate at a low speed. At the same time, the motor 81 drives the main shaft 2 to rotate at a high speed via belt drive. At this time, the rotation direction of the main shaft 2 is the same as the rotation direction of the output shaft of the motor 81, which allows the main shaft 2 to rotate in the opposite direction relative to the screen 3.

[0048] Reference Figure 1 and Figure 2 The outer arc surface of the screening chamber 101 is provided with an observation window 106. Operators can observe the screening status of the drug powder in the screening chamber 101, the material accumulation, and the cleanliness of the screen 3 in real time through the observation window 106. This facilitates timely detection of screening abnormalities and the implementation of countermeasures to prevent the malfunction from escalating and affecting production efficiency.

[0049] The implementation principle of a powder screening device for drug production according to an embodiment of this application is as follows: When the screening device is working, the material to be screened is first put into the feed hopper 102. After the motor 81 is started, the motor 81 drives the main shaft 2 to rotate at high speed through belt drive. The spiral blade 27 on the right side of the main shaft 2 rotates synchronously, pushing the material in the feed hopper 102 into the screen 3. While the main shaft 2 rotates, the impeller blades 23, which are fixedly installed on its outer side through the bushing 21 and the sleeve 22, rotate at high speed inside the screen 3, driving the airflow inside the screen 3 to form a spiral vortex. The material is subjected to the combined action of radial centrifugal force and axial spiral propulsion force in the vortex field. The radial centrifugal force drives the material to stick tightly to the screen 3, while the axial spiral propulsion force drives the coarse material to move towards the tail end of the screen 3. The fine powder passes through the screen 3 with the help of centrifugal force and airflow energy, and the coarse and fine materials are initially separated. The screened fine material is discharged from the fine material outlet 103 at the bottom of the screening hopper 101, while the coarse material moves towards the tail end along the inner wall of the screen 3.

[0050] To enhance the screening effect and reduce the probability of screen 3 clogging, after the motor 81 is started, the rotating shaft 82 is driven to rotate via belt drive. The rotating shaft 82 meshes with the teeth on the drive ring 7 through the gear 821, causing the drive ring 7 and screen 3 to rotate in the opposite direction relative to the output shaft of the motor 81. The arc groove 71 on the inner wall of the drive ring 7 cooperates with the corresponding arc strip 31 on the outer side of the screen 3, causing the screen 3 to rotate slowly in the opposite direction relative to the impeller blades 23. The relative motion between the two reduces the problem of material sticking to the screen and clogging caused by electrostatic adsorption and slight stickiness. At the same time, the external air source sprays air onto the outer side of the screen 3 through the nozzle 105, which forms a backflow effect on the screen 3, further avoiding the risk of clogging. It can also promote the material to contact the entire circumference of the screen 3 evenly, effectively improving the screening rate and fine powder recovery rate. In addition, during screening, the coarse material moves to the left end of the screen 3 under the action of airflow. The impeller 32 can block the coarse material, increase the residence time of the material inside the screen 3, and allow the material to fully participate in screening. This greatly reduces the probability that the fine material will be discharged from the coarse material outlet 104 along with the coarse material. Then, the impeller 32 rotates with the screen 3, pushing the coarse material gathered at the left end to the coarse material outlet 104 for discharge, thus completing the screening of the material.

[0051] In the screening state, the elastic force of spring 26 applies a driving force to T-shaped rod 25, moving it closer to the main shaft 2, so that the sealing plate 4 is completely hidden in the sliding groove 231 inside the impeller blade 23, without affecting the screening operation of the impeller blade 23 on the material. When it is necessary to clean the inside of the screen 3, the external air source introduces high-pressure gas into the through hole in the middle of the main shaft 2 through the air connector 91 and the sealing cover 9. The high-pressure gas enters the sliding groove 231 inside the impeller blade 23 through the air pipe 24. At this time, because the sealing plate 4 is in a hidden state, its outer air groove 41 remains closed. Under the action of air pressure, the sealing plate 4 slides out from the sliding groove 231 and approaches the screen 3, which can scrape and clean the agglomerates adhering to the inner wall of the screen 3. At the same time, the outer air groove 41 of the sealing plate 4 separates from the inner wall of the sliding groove 231, and the high-pressure gas forms an airflow through the air groove 41 to blow the screen 3. With the slow rotation of the screen 3, the screen 3 is cleaned in all directions.

[0052] As the sealing plate 4 slides out of the chute 231, the adjusting stud 5 on its outer side cooperates with the stepped hole 6 corresponding to the outer side of the impeller blade 23 to limit the maximum movement position of the sealing plate 4. This ensures that the sealing plate 4 can approach the screen 3 to scrape and clean larger agglomerates adhering to the inner wall, while maintaining a reasonable distance from the screen 3 to avoid mechanical wear caused by direct contact, significantly reducing the probability of screen 3 failure. At the same time, by rotating the adjusting stud 5, the initial distance between it and the stepped surface inside the stepped hole 6 can be adjusted, thereby flexibly adjusting the maximum movement position of the sealing plate 4 to adapt to different screening scenarios and material characteristics, improving the applicability of the device.

[0053] Furthermore, in the description of this application, the terms "installation", "connection", "linking", and "setting" should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

Claims

1. A powder screening device for pharmaceutical production, comprising a frame (1) and a screening chamber (101) disposed at the upper end of the frame (1), wherein a feed chamber (102) is disposed at the right end of the screening chamber (101), characterized in that: The screening chamber (101) is rotatably connected to a screen (3), and the feed chamber (102) is rotatably connected to a main shaft (2). The main shaft (2) and the screen (3) are coaxially arranged. A bushing (21) is fixedly installed on the outside of the main shaft (2). A sleeve (22) is arranged in a circumferential array on the outside of the bushing (21). The outer sides of the sleeves (22) corresponding to the axial direction are fixedly connected to the wind turbine blades (23). A sealing plate (4) is slidably connected in the sliding groove (231) opened inside the wind turbine blades (23). An air groove (41) corresponding to the position of the screen (3) is opened on the side of the sealing plate (4). An air hole (42) for connecting the air groove (41) and the sliding groove (231) is evenly opened inside the sealing plate (4). The sliding groove (231) is connected to the through hole in the middle of the main shaft (2) through the air pipe (24).

2. The powder screening device for pharmaceutical production according to claim 1, characterized in that: The sleeve (22) is slidably connected with T-shaped rods (25). The outer ends of the T-shaped rods (25) are fixedly connected to the corresponding sealing plates (4) in the axial direction. The outer sides of the T-shaped rods (25) are all fitted with springs (26). The springs (26) apply a driving force to the T-shaped rods (25) to move closer to the main shaft (2) and enable the sealing plates (4) to be completely hidden in the grooves (231) inside the wind turbine blades (23).

3. The powder screening device for pharmaceutical production according to claim 1, characterized in that: The outer side of the sealing plate (4) is threaded with an adjusting stud (5), and the outer side of the wind turbine blade (23) is provided with a stepped hole (6) that seals with the adjusting stud (5).

4. The powder screening device for pharmaceutical production according to claim 1, characterized in that: The screening chamber (101) is rotatably connected to a drive ring (7). The inner arc surface of the drive ring (7) is uniformly provided with arc grooves (71). The outer end of the screen (3) is uniformly provided with arc strips (31) that are inserted into the arc grooves (71). The frame (1) is provided with a drive assembly (8) for driving the drive ring (7) to rotate.

5. A powder screening device for pharmaceutical production according to claim 1, characterized in that: The bottom of the screening chamber (101) is provided with a fine material outlet (103) and a coarse material outlet (104). The end of the screen (3) near the coarse material outlet (104) is provided with an impeller (32) for pushing the coarse material to the coarse material outlet (104). The middle part of the impeller (32) is rotatably connected to the main shaft (2). The impeller (32) is located between the fine material outlet (103) and the coarse material outlet (104).

6. The powder screening device for pharmaceutical production according to claim 1, characterized in that: The outer arc surface of the screening chamber (101) is evenly distributed with nozzles (105) corresponding to the positions of the screen (3), and the nozzles (105) are all connected to an external high-pressure air source.

7. A powder screening device for pharmaceutical production according to claim 5, characterized in that: The screening chamber (101) is fixedly installed with a cover (9) on the side near the coarse material outlet (104). The left end of the main shaft (2) is movably inserted into the inside of the cover (9). The outer side of the cover (9) is provided with an air connector (91) for supplying air to the inside of the main shaft (2).

8. A powder screening device for pharmaceutical production according to claim 4, characterized in that: The drive assembly (8) includes a motor (81) disposed on the outside of the frame (1). The screening chamber (101) is rotatably connected to a rotating shaft (82). One end of the rotating shaft (82) is provided with a gear (821), and the gear (821) meshes with the teeth evenly distributed on the outer arc surface of the drive ring (7). The motor (81) can drive the rotating shaft (82) to rotate by belt drive.

9. A powder screening device for pharmaceutical production according to claim 8, characterized in that: The right end of the main shaft (2) is rotatably connected to the inner wall of the feed bin (102), and a spiral blade (27) for feeding is provided at the right end of the main shaft (2). The spiral blade (27) is located inside the feed bin (102), and the motor (81) can drive the main shaft (2) to rotate by belt drive.

10. A powder screening device for pharmaceutical production according to claim 1, characterized in that: The outer arc surface of the screening chamber (101) is provided with an observation window (106).

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