Double-distributor bottom-spraying conical circulation bed for pellet coating
By using a double distributor bottom spray conical circulation bed and a ring tube distributor in the micropillar coated fluidized bed, a circulation structure is formed and the air inlet volume is adjusted, which solves the problems of poor application flexibility of the equipment and loss of micropillar particles, and a more efficient micropillar coating process is achieved.
Patent Information
- Application Number
- CN202411948752.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-04-01
AI Technical Summary
The existing micropill coated fluidized bed technology has poor application flexibility when the micropill particle size changes, which can easily cause micropill particle loss.
A double distributor bottom spray conical circulation bed is adopted. By setting up a flow tube and a ring tube distributor in the conical fluidized bed, a circulation structure is formed to achieve an orderly circulation of the micropellet particles, and the air inlet volume is adjusted through the air volume controller to adapt to the prescription of different preparations.
The orderly circulation and coating efficiency of micro-pellets are improved, the operation flexibility of the equipment is increased, the loss of micro-pellets is reduced, and a more efficient coating process is achieved.
Smart Images
Figure CN119732841A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of pharmaceutical engineering technology, and in particular to a double-distributor bottom-spray conical annular fluidized bed for pellet coating. Background Art
[0002] Micropellets are small spherical oral solid dosage forms with a diameter of less than 2.5 mm. They have the advantages of good fluidity and uniform quality. They can achieve taste masking, moisture resistance, light shielding, anti-oxidation, gastrointestinal solubility, sustained and controlled release, reduce gastric mucosal irritation, and improve bioavailability. The formulation, process and equipment structure of micropellet coating preparations are directly related to the uniform density of the coating drug-loaded film, thereby affecting the drug release effect.
[0003] At present, the microcapsule coating technologies at home and abroad include coating pan method, centrifugal granulation method, condensation granulation method, fluidized bed method, etc. Among them, the bottom spray Wurster fluidized bed technology has outstanding advantages such as good uniformity of coating film formation within the batch, high efficiency, less coating liquid loss, good batch reproducibility, and wide application range. It is currently a widely used device in the microcapsule preparation and sustained-release coating process. The device mainly adopts a combined structure of a conical fluidized bed and a guide tube. During the operation, the microcapsule particles can form an orderly and directional circulation flow. The coating liquid droplets and the microcapsules move in the same direction, so that the microcapsule particles and any angle of the surface have equal opportunities to contact the droplets. After the interphase transfer process of droplet sedimentation, coating, spreading film formation, water evaporation, and close accumulation of polymer particles, a uniform, continuous and dense coating film is finally formed. At present, the relevant research on this technology has made substantial progress and has been industrialized.
[0004] However, as the formulation process and pellet particle size change, the air volume in the fluidized air domain needs to be redistributed, resulting in the need to frequently replace and adjust the porosity and distribution design of the gas porous distribution plate in the bottom spray Wurster device. At the same time, some pellets above the distribution plate are retained, accumulated and lost, reducing the flexibility of equipment application and causing the loss of some pellet particles. Summary of the invention
[0005] In order to improve the problem of poor equipment application flexibility and easy loss of micro-pill particles in the existing fluidized bed technology when the particle size of micro-pills changes, the present application provides a double distributor bottom spray conical annular fluidized bed for micro-pill coating.
[0006] The present application provides a double distributor bottom spray conical annular fluidized bed for pellet coating, which adopts the following technical solution: A double distributor bottom spray conical annular fluidized bed for pellet coating, comprising: The straight section has a feeding port on its side wall and a bag filter on the top; A cone section is connected to the lower part of the straight cylinder section, and a flow guide pipe is coaxially arranged inside the cone section, and the flow guide pipe and the cone section form a conical annular flow bed; A showerhead distributor is located in the cone section and is arranged below the guide pipe and is connected to an air source. An air heater is arranged on the pipeline of the showerhead distributor. The showerhead plane of the showerhead distributor is flush with the bottom end of the cone section. A dual-fluid atomizing nozzle, used for conveying the coating liquid, and arranged in the middle of the top of the showerhead distributor and pointing to the bottom of the guide tube; and The annular tube distributor is arranged around the outer periphery of the shower head distributor and is arranged with a gap between the guide tube and the inner wall of the cone section. The air outlet of the annular tube distributor is arranged in a direction away from the guide tube.
[0007] Furthermore, the annular tube distributor is located between the shower head distributor and the flow guide pipe.
[0008] Furthermore, the annular tube distributor is at least 50 mm higher than the shower head plane of the shower head distributor.
[0009] Furthermore, the opening direction of the annular tube distributor is toward the outermost side of the shower head plane of the shower head distributor.
[0010] Furthermore, the annular pipe distributor is connected to at least two air inlet pipes.
[0011] Furthermore, the internal space of the guide tube is the coating zone, the annular space between the guide tube and the cone section is the circulation zone, the space below the cross-section of the guide tube is the bottom zone, and the space above is the drying zone, and the micro-pellet particles flow through the coating zone, the drying zone, the circulation zone and the bottom zone in sequence to complete the internal circulation flow.
[0012] Furthermore, the opening diameter of the showerhead distributor is larger than the particle diameter of the micropills, and a discharge port is provided at the turning position of the vertical section of the pipeline of the showerhead distributor.
[0013] Furthermore, the cone section is made of transparent material.
[0014] Furthermore, the air flow velocity in the showerhead distributor is greater than the air flow velocity in the annular tube distributor, and the distance between the guide tube and the showerhead distributor is 5 to 20 mm, and the inclination angle of the cone section is 10° to 20°.
[0015] Furthermore, a first flow solenoid valve is provided on the air pipeline of the shower head distributor, and a second solenoid flow valve is provided on the air pipeline of the ring tube distributor. The first flow solenoid valve and the second flow solenoid valve are commonly connected to an air volume controller, and the air volume controller is used to control the air intake of the coating area and the circulation area, and the air intake per unit time of the coating area is 3 to 8 times the air intake per unit time of the circulation area.
[0016] In summary, the present application includes at least one of the following beneficial technical effects: 1. By setting a guide tube in the conical fluidized bed, a circulation structure can be formed. On the one hand, the guide tube can realize the orderly circulation of the micro-pellets in the conical fluidized bed through regular particle flow, especially the radial flow of the micro-pellets in the bottom area of the guide tube helps to break the bubbles and enhance the multi-phase contact efficiency; on the other hand, the advantages of the partitioned reaction based on regular flow are highlighted. Specifically, the gas and solid phases in the coating area of the guide tube flow upward in parallel in a manner similar to plug flow, while the high-density micro-pellets flow downward in the countercurrent in the circulation area, which maximizes the driving force of the orderly circulation of the micro-pellets, improves the mass transfer, heat transfer and mixing efficiency of the micro-pellets, and the bed temperature is easy to control, which can achieve efficient contact between the micro-pellets and the coating droplets; 2. With the help of the orderly circulation of the pellet particles in the device, the process technology requirements of the pellet coating process for coating uniformity and density are met; and due to the zoning coordination of the coating area, drying area, circulation area and bottom area, the fluidization air volume in different flow areas can be reasonably adjusted according to the actual particle properties and process requirements to control the coating rate intensity, thereby increasing the operational flexibility of the production device; 3. The downward angle of the opening of the ring tube distributor can be processed according to the material properties and the installation position of the ring tube distributor and the shower head distributor. It is expected to reduce the accumulation of micro-pellets at the bottom, improve the loss of micro-pellets, and increase the utilization rate of micro-pellets; 4. Compared with the single-structure distribution plate in the prior art, once the formulation process conditions change and the required optimal air volume changes, the opening size of the distribution plate needs to be frequently changed to obtain the optimal air volume in the coating area and the circulation area. The micro-pill coating double distributor bottom spray conical circulating bed of the present application only needs to control the first flow solenoid valve and the second solenoid flow valve corresponding to the showerhead distributor and the ring tube distributor through the air volume controller to flexibly adjust the zones when the optimal air volume in the coating area and the circulation area required by different formulation prescription processes are different, which can greatly improve the operating range and flexibility of the device, and at the same time improve the fluidization state of the micro-pill particles at the bottom of the bed, and has the advantages of efficient gas-solid contact, multi-zone coordinated control, large operating flexibility, and high coating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0018] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application; Figure 2 This is a simplified installation diagram of a showerhead distributor and a ring-tube distributor according to an embodiment of the present application; Figure 3 is a top view of a showerhead distributor and a ring-tube distributor according to an embodiment of the present application; Figure 4 Schematic diagram of the inner circulation flow direction of the micro-pellet particles in the embodiment of the present application; Figure 5 It is a schematic diagram of the air flow direction of an embodiment of the present application.
[0019] Reference numerals: 11. Straight section; 111. Feeding port; 12. Conical section; 13. Bottom section; 2. Bag filter; 3. Flow guide pipe; 41. Shower head distributor; 42. Air heater; 43. Discharge port; 5. Double fluid atomizing nozzle; 6. Ring pipe distributor; 61. Air inlet pipe; 71. Coating area; 72. Drying area; 73. Circulation area; 74. Bottom area. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0021] Reference Figure 1 , Figure 2 and Figure 3 The present application discloses a double distributor bottom spray conical annular fluidized bed for pellet coating, which comprises: The straight section 11 has a feeding port 111 on its side wall and a bag filter 2 on its top; The cone section 12 is connected to the lower part of the straight cylinder section 11, and a flow guide pipe 3 is coaxially arranged inside the cone section 12. There is a gap between the flow guide pipe 3 and the inner wall of the cone section 12, and the flow guide pipe 3 and the cone section 12 form a conical annular flow bed; specifically, the inclination angle of the cone section is 10° to 20°; The showerhead distributor 41 is located in the conical section 12 and is arranged below the flow guide pipe 3 and is connected to the air source. An air heater 42 is arranged on the pipeline of the showerhead distributor 41. The showerhead plane of the showerhead distributor 41 is flush with the bottom end of the conical section 12. A dual-fluid atomizing nozzle 5, used for conveying the coating liquid, and arranged in the middle of the top of the showerhead distributor 41 and pointing to the bottom of the flow guide tube 3; and The annular tube distributor 6 is connected to the air source and is arranged around the outer periphery of the shower head distributor 41 , and is arranged with a gap between the guide tube 3 and the inner wall of the cone section 12 . The air outlet of the annular tube distributor 6 is arranged in a direction away from the guide tube 3 .
[0022] Specifically, the above-mentioned annular tube distributor 6 is located between the shower head distributor 41 and the guide pipe 3, the annular tube distributor 6 is at least 50 mm higher than the shower head plane of the shower head distributor 41, the distance between the guide pipe 6 and the shower head distributor 41 is 5 to 20 mm, and the air outlet opening direction of the annular tube distributor 6 is toward the outermost side of the shower head plane of the shower head distributor 41, and the annular tube distributor 6 is connected to at least two air inlet pipes 61 connected to the air source.
[0023] And, refer to Figure 4 and Figure 5 The inner space of the guide tube is the coating zone 71, in which the coating material is efficiently and evenly coated on the micro-pellet particles; the annular space between the guide tube and the cone section 12 is the circulation zone 73, which mainly provides a process for the micro-pellet particles to flow downward in a directional manner; the space below the guide tube cross section is the bottom zone 74, and the space above is the drying zone 72. The drying zone 72 mainly completes the stable drying process of the coating material on the surface of the micro-pellet particles, and the bottom zone 74 mainly completes the process of lateral transportation of the micro-pellet particles to the projection area of the coating zone 71 and initial contact with the coating droplets. The micro-pellet particles flow through the coating zone 71, the drying zone 72, the circulation zone 73 and the bottom zone 74 in sequence to complete the internal circulation flow.
[0024] In this way, the pellets enter the bed layer composed of the straight tube section 11 and the conical section 12 through the feed port 111. One path of air is heated to about 50°C by the air heater 42, and then enters the bottom of the guide tube 3 through the showerhead distributor 41; at the same time, the other path of air enters the bottom of the annular space composed of the guide tube 3 and the fluidized bed conical section 12 through the annular tube distributor 6, and forms a violent turbulent contact with the pellets. At the same time, the double-fluid atomizing nozzle 5 atomizes the coating liquid and sprays it into the bottom of the guide tube and the internal bed layer, so that the pellets flow in a regular internal circulation manner in the conical annular bed.
[0025] Specifically, air is introduced into the coating area 71 by the showerhead distributor 41 and into the circulation area 73 by the annular distributor 6, and then flows upward after merging in the drying area 72, and finally discharged after passing through the bag filter 2. The pellet particles continuously flow through the coating area 71, the drying area 72, the circulation area 73 and the bottom area 74 in the conical annular bed. During this internal circulation flow process, the pellet particles are in contact with the atomized coating liquid in the bottom area 74 and the coating area 71 in the same direction, and then the atomized droplets settle, coat, spread and form a film on the surface of the pellet particles in the internal circulation, the water evaporates, and the polymer particles are closely accumulated to form a dense and uniform coating film. Subsequently, the pellet particles are entrained by the gas to the drying area 72 above the cross section of the guide tube for drying. Since the bag filter 2 is installed in the top space of the straight section 11, when the gas is vented, the micro-pellets return to the circulation area 73 for circulation. After the coating process is completed, the annular tube distributor 6 and the shower head distributor 41 are closed, and the micro-pellets can be discharged for packaging.
[0026] Therefore, by setting the guide tube 3 in the conical fluidized bed, a circulation structure can be formed. On the one hand, the guide tube 3 can realize the orderly circulation of the micro-pellets in the conical fluidized bed through the regular particle flow, especially the radial flow of the micro-pellets in the bottom area 74 of the guide tube helps to break the bubbles and enhance the multi-phase contact efficiency. On the other hand, the advantages of the partition reaction based on regular flow are highlighted. Specifically, the gas and solid phases in the coating area 71 of the guide tube 3 flow upward in parallel in an approximately plug flow manner, while the high-density micro-pellets flow downward in the countercurrent in the circulation area 73, which maximizes the driving force of the orderly circulation of the micro-pellets, improves the mass transfer, heat transfer and mixing efficiency of the micro-pellets, and the bed temperature is easy to control, which can achieve efficient contact between the micro-pellets and the coating droplets. Thirdly, the orderly circulation of the micro-pellets in the device meets the process technology requirements of the micro-pellet coating process for coating uniformity and density. Fourthly, due to the zone coordinated control, the fluidizing air volume in different flow areas can be reasonably adjusted to control the coating rate intensity according to the actual particle properties and process requirements, thereby increasing the operational flexibility of the production unit.
[0027] In addition, the downward angle of the opening of the annular tube distributor 6 can be processed according to the material properties and the installation position of the annular tube distributor 6 and the showerhead distributor 41. Figure 3 As shown, the showerhead distributor 41 opening and the installation position with the annular tube distributor 6 are as shown in the attached Figure 2 As shown, it is expected that the accumulation of micro-pellets at the bottom can be reduced, the loss of micro-pellets can be improved, and the utilization rate of micro-pellets can be increased.
[0028] In addition, in order to facilitate the effective control of the fluidizing air volume in each zone, the air flow velocity in the shower head distributor 41 is greater than the air flow velocity in the annular tube distributor 6, and a first flow solenoid valve and a first gas rotor flowmeter are provided on the air path of the shower head distributor 41, and a second solenoid flow valve and a second gas rotor flowmeter are provided on the air path of the annular tube distributor 6. The first flow solenoid valve and the second flow solenoid valve are commonly connected to an air volume controller, and the air volume controller is electrically connected to the first gas rotor flowmeter and the second gas rotor flowmeter. The air volume controller is used to control the air intake of the coating zone 71 and the circulation zone 73. Specifically, during control, the air intake per unit time of the coating zone is 3 to 8 times the air intake per unit time of the circulation zone.
[0029] Therefore, compared with the single-structure distribution plate in the prior art, once the formulation process conditions change and the required optimal air volume changes, the opening size of the distribution plate needs to be frequently changed to obtain the optimal air volume in the coating zone 71 and the circulation zone 73. For the micro-pill coating double distributor bottom spray conical circulating bed of the present application, when the optimal air volume in the coating zone 71 and the circulation zone 73 required by different formulation prescription processes is different, it is only necessary to control the first flow solenoid valve and the second solenoid flow valve corresponding to the showerhead distributor 41 and the ring tube distributor through the air volume controller to flexibly adjust the partition, which can greatly improve the operating range and flexibility of the device, and at the same time improve the fluidization state of the micro-pill particles at the bottom of the bed, and has the advantages of efficient gas-solid contact, multi-zone coordinated control, large operating flexibility, and high coating efficiency.
[0030] Moreover, refer to Figure 1 The opening diameter of the showerhead distributor 41 is larger than the particle diameter of the pellets, and a discharge port 43 is provided at the turning position of the vertical section of the pipeline of the showerhead distributor 41, and the cone section 12 is made of a transparent material, such as organic glass.
[0031] Therefore, with the help of the transparent setting of the cone section 12, the orderly circulation of the micro-pellet particles in the conical fluidized bed can be conveniently observed in real time; and when the micro-pellet particles are processed, the air supply to the shower head distributor 41 and the ring tube distributor is stopped, and the processed micro-pellet particles enter the pipeline of the shower head distributor 41 from the opening at the top of the shower head distributor 41, and are discharged through the discharge port 43. If the discharge is not smooth, the shower head distributor 41 can also be backblown.
[0032] In addition, refer to Figure 1 and Figure 2 A bottom section 13 is also fixedly connected to the bottom end of the cone section 12. The bottom section 13 is not connected to the bottom of the cone section 12 and is used to wrap and fix the air pipelines of the shower head distributor 41 and the ring pipe distributor.
[0033] The implementation principle of a double distributor bottom spray conical annular fluidized bed for pellet coating in the present application is: The air is introduced into the coating area 71 by the showerhead distributor 41 and the circulation area 73 by the annular distributor 6 at the same time. After merging in the drying area 72, the air flows upward and finally passes through the bag filter 2. The pellets flow through the coating area 71, the drying area 72, the circulation area 73 and the bottom area 74 in the conical annular bed. During this internal circulation flow process, the pellets are in contact with the atomized coating liquid in the bottom area 74 and the coating area 71 in the same direction. Then, the atomized droplets settle, coat, spread and form a film on the surface of the pellets in the internal circulation, the water evaporates and the polymer particles are closely accumulated to form a dense and uniform coating film. Subsequently, the pellets are entrained by the gas to the drying area 72 above the cross section of the guide tube for drying. Since the bag filter 2 is installed in the top space of the straight section 11, when the gas is vented, the micro-pellets return to the circulation area 73 for circulation. After the coating process is completed, the annular tube distributor 6 and the shower head distributor 41 are closed, and the micro-pellets can be discharged for packaging.
[0034] By setting the guide tube 3 in the conical fluidized bed, a circulation structure can be formed. On the one hand, the guide tube 3 can realize the orderly circulation of the micro-pellets in the conical fluidized bed through the regular particle flow, especially the radial flow of the micro-pellets in the bottom area 74 of the guide tube helps to break the bubbles and enhance the multi-phase contact efficiency. On the other hand, the advantages of the partition reaction based on regular flow are highlighted. Specifically, the gas and solid phases in the coating area 71 of the guide tube 3 flow upward in parallel in an approximately plug flow manner, while the high-density micro-pellets flow countercurrently downward in the circulation area 73, which maximizes the driving force of the orderly circulation of the micro-pellets, improves the mass transfer, heat transfer and mixing efficiency of the micro-pellets, and the bed temperature is easy to control, which can achieve efficient contact between the micro-pellets and the coating droplets. Thirdly, the orderly circulation of the micro-pellets in the device meets the process technology requirements of the micro-pellet coating process for coating uniformity and density. Fourthly, due to the zone coordinated control, the fluidizing air volume in different flow areas can be reasonably adjusted to control the coating rate intensity according to the actual particle properties and process requirements, thereby increasing the operational flexibility of the production unit.
[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A double distributor bottom spray conical annular fluidized bed for pellet coating, characterized in that: include: The straight section has a feeding port on its side wall and a bag filter on the top; A cone section is connected to the lower part of the straight cylinder section, and a flow guide pipe is coaxially arranged inside the cone section, and the flow guide pipe and the cone section form a conical annular flow bed; A showerhead distributor is located in the cone section and is arranged below the guide pipe and is connected to an air source. An air heater is arranged on the pipeline of the showerhead distributor. The showerhead plane of the showerhead distributor is flush with the bottom end of the cone section. A dual-fluid atomizing nozzle, used for conveying the coating liquid, and arranged in the middle of the top of the showerhead distributor and pointing to the bottom of the guide tube; and The annular tube distributor is arranged around the outer periphery of the shower head distributor and is arranged with a gap between the guide tube and the inner wall of the cone section. The air outlet of the annular tube distributor is arranged in a direction away from the guide tube.
2. A double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 1, characterized in that: The annular tube distributor is located between the shower head distributor and the flow guide pipe.
3. The double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 2, characterized in that: The annular tube distributor is at least 50 mm higher than the shower head plane of the shower head distributor.
4. A double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 3, characterized in that: The opening direction of the annular tube distributor is toward the outermost side of the shower head plane of the shower head distributor.
5. The double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 1, characterized in that: The annular pipe distributor is connected with at least two air inlet pipes.
6. The double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 1, characterized in that: The inner space of the guide tube is the coating zone, the annular space between the guide tube and the cone section is the circulation zone, the space below the cross section of the guide tube is the bottom zone, and the space above is the drying zone. The pellet particles flow through the coating zone, the drying zone, the circulation zone and the bottom zone in sequence to complete the internal circulation flow.
7. The double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 1, characterized in that: The opening diameter of the showerhead distributor is larger than the particle diameter of the micropills, and a discharge port is arranged at the turning position of the vertical section of the pipeline of the showerhead distributor.
8. The double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 1, characterized in that: The cone section is made of transparent material.
9. A double distributor bottom spray conical annular fluidized bed for pellet coating according to any one of claims 1 to 8, characterized in that: The air flow velocity in the showerhead distributor is greater than the air flow velocity in the annular tube distributor, and the distance between the guide pipe and the showerhead distributor is 5 to 20 mm, and the inclination angle of the cone section is 10° to 20°.
10. A double distributor bottom spray conical annular fluidized bed for pellet coating according to claim 9, characterized in that: A first flow solenoid valve is arranged on the air pipeline of the shower head distributor, and a second solenoid flow valve is arranged on the air pipeline of the ring tube distributor. The first flow solenoid valve and the second flow solenoid valve are commonly connected to an air volume controller, and the air volume controller is used to control the air intake of the coating area and the circulation area, and the air intake per unit time of the coating area is 3 to 8 times the air intake per unit time of the circulation area.