A sealing mechanism for a dry granulator

Abstract

The utility model relates to dry granulation technical field discloses a kind of sealing mechanism for dry granulator, including granulator, the outer wall side of granulator is equipped with conveying structure, it spirally conveys material to the inside of granulator, the inside one end of conveying structure is equipped with sealing mechanism, it is sealed to conveying structure, the outside of sealing mechanism is also equipped with cooling structure, it is cooled to sealing mechanism;The conveying structure includes conveying pipe, one end of the conveying pipe is connected with granulator, another end of the conveying pipe is fixedly connected with conveying motor.In the utility model, high-strength magnetic field formed in radial gap by magnetic circuit assembly captures magnetic fluid, forming liquid seal ring.The sealing ring can adapt to the rotating conveying shaft, maintain complete sealing interface, eliminate the reverse leakage of powder material, and ensure the pressure stability of the granulation process.Because of the liquid contact between magnetic fluid and conveying shaft, mechanical wear is reduced.

Description

Technical Field

[0001] This utility model relates to the field of dry granulation technology, and in particular to a sealing mechanism for a dry granulation machine. Background Technology

[0002] Dry granulation machines are key equipment in the pharmaceutical and chemical industries, used to directly granulate powdered materials through processes such as extrusion, crushing, and granulation. Their core working units include a screw conveyor structure and a pressure roller structure. The screw conveyor structure is responsible for continuously and stably conveying the powdered material between the two pressure rollers and creating the necessary pre-compression pressure, which is a prerequisite for ensuring the quality of granulation.

[0003] In this field, the dynamic sealing reliability of screw conveyor structures has always been a technical challenge. Currently, common sealing solutions mostly employ packing seals or mechanical seals. Packing seals rely on the tight contact between the packing and the rotating shaft, which inevitably involves wear, and this wear causes significant mechanical damage.

[0004] Furthermore, both packing seals and mechanical seals generate significant heat due to friction during long-term operation. If this heat cannot be dissipated in time, it can lead to thermal deformation and accelerated wear of the sealing elements, or even failure under high heat. Summary of the Invention

[0005] To overcome the above shortcomings, this utility model provides a sealing mechanism for a dry granulation machine, which aims to improve the problem that the existing packing seal relies on the tight contact between the compressed packing and the rotating shaft, resulting in significant wear.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a sealing mechanism for a dry granulator, comprising a granulator, wherein a conveying structure is installed on one side of the outer wall of the granulator, which conveys the material into the granulator via a screw conveyor, and a sealing mechanism is provided at one end of the inner side of the conveying structure to seal the conveying structure; and a cooling structure is also provided outside the sealing mechanism to cool the sealing mechanism. The conveying structure includes a conveying pipe, one end of which is connected to the granulator, and the other end of which is fixedly connected to a conveying motor. The output end of the conveying motor passes through the outer wall of the conveying pipe and is fixedly connected to a conveying shaft. A conveying auger is installed on the outside of the conveying shaft, and a feed inlet is provided at the top of the conveying pipe.

[0007] As a further description of the above technical solution: The sealing mechanism includes a sealing housing, which is installed on the outer wall of the conveying shaft. The sealing housing has a magnetic circuit assembly inside, which includes an annular permanent magnet and a pair of pole shoes symmetrically arranged on both sides of the annular permanent magnet. The pole shoes have pole teeth on their outer sides, and a radial gap is formed between the pole teeth and the surface of the conveying shaft. The radial gap is filled with a magnetic fluid.

[0008] As a further description of the above technical solution: The sealed housing is further provided with a magnetic shielding shell, and the magnetic circuit assembly is disposed inside the magnetic shielding shell. The material of the magnetic shielding shell is austenitic stainless steel.

[0009] As a further description of the above technical solution: The cooling structure includes a cooling jacket that surrounds the outside of the magnetic shielding shell, and the interior of the cooling jacket is filled with coolant.

[0010] As a further description of the above technical solution: A miniature shaft is installed on one side of the outer wall of the cooling jacket, and a permanent magnet impeller is rotatably connected to one end of the miniature shaft.

[0011] As a further description of the above technical solution: The cooling jacket is made of either stainless steel or plastic.

[0012] As a further description of the above technical solution: A liquid injection hole is provided on one side of the outer wall of the sealing shell, and a guide plate connected to the inner wall of the sealing shell is provided below the liquid injection hole.

[0013] This utility model has the following beneficial effects: In this invention, a high-intensity magnetic field formed by a magnetic circuit assembly in the radial gap traps the magnetofluid, forming a liquid sealing ring. This sealing ring can adaptively rotate the conveyor shaft, maintaining a complete sealing interface, preventing reverse leakage of powder materials, and ensuring stable pressure during the granulation process. Because the magnetofluid and the conveyor shaft are in liquid contact, mechanical wear is reduced, significantly improving the service life and reliability of the sealing mechanism.

[0014] In this invention, a forced circulation cooling system driven by a permanent magnet impeller and integrated within the cooling jacket can actively and efficiently remove the heat generated during the operation of the magnetic circuit components. This active heat dissipation mechanism ensures that the magnetofluid is always within its optimal operating temperature range, effectively preventing performance degradation or failure due to overheating, and guaranteeing the long-term stability of the sealing effect. It is particularly suitable for pharmaceutical production conditions that require long-term continuous operation. Attached Figure Description

[0015] Figure 1This is a perspective view of a sealing mechanism for a dry granulation machine proposed in this utility model; Figure 2 This is a diagram illustrating a sealing mechanism for a dry granulator according to the present invention. Figure 3 This is an exploded view of a sealing mechanism for a dry granulator proposed in this utility model; Figure 4 This is a cross-sectional view of a sealing mechanism for a dry granulator proposed in this utility model.

[0016] Legend: 1. Granulator; 2. Conveying structure; 21. Conveying pipe; 22. Conveying motor; 23. Conveying shaft; 24. Conveying auger; 25. Feed inlet; 3. Sealing mechanism; 31. Sealing housing; 32. Magnetic circuit assembly; 321. Ring permanent magnet; 322. Pole shoe; 323. Pole tooth; 324. Radial clearance; 325. Magnetorheological fluid; 33. Magnetic shield; 311. Liquid injection hole; 312. Guide plate; 4. Cooling structure; 41. Cooling jacket; 42. Coolant; 43. Miniature shaft; 44. Permanent magnet impeller. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] Reference Figure 1-4 An embodiment of this utility model is provided: a sealing mechanism for a dry granulator, including a granulator 1, a conveying structure 2 installed on one side of the outer wall of the granulator 1, which conveys the material into the granulator 1 by a screw conveyor, a sealing mechanism 3 provided at one end of the inner side of the conveying structure 2, which seals the conveying structure 2, and a cooling structure 4 provided outside the sealing mechanism 3, which cools the sealing mechanism 3. The conveying structure 2 includes a conveying pipe 21. One end of the conveying pipe 21 is connected to the granulator 1. The other end of the conveying pipe 21 is fixedly connected to a conveying motor 22. The output end of the conveying motor 22 passes through the outer wall of the conveying pipe 21 and is fixedly connected to a conveying shaft 23. A conveying auger 24 is installed on the outside of the conveying shaft 23. A feed inlet 25 is provided at the top of the conveying pipe 21.

[0019] The sealing mechanism 3 includes a sealing housing 31, which is installed on the outer wall of the conveying shaft 23. The sealing housing 31 is provided with a magnetic circuit assembly 32. The magnetic circuit assembly 32 includes an annular permanent magnet 321 and a pair of pole shoes 322 symmetrically arranged on both sides of the annular permanent magnet 321. The pole shoes 322 are provided with pole teeth 323 on the outside. A radial gap 324 is formed between the pole teeth 323 and the surface of the conveying shaft 23. The radial gap 324 is filled with a magnetic fluid 325. The sealed housing 31 is further provided with a magnetic shielding shell 33, and the magnetic circuit assembly 32 is disposed inside the magnetic shielding shell 33. The material of the magnetic shielding shell 33 is austenitic stainless steel.

[0020] A liquid injection hole 311 is provided on one side of the outer wall of the sealing housing 31, and a guide plate 312 connected to the inner wall of the sealing housing 31 is provided below the liquid injection hole 311.

[0021] Specifically, the annular permanent magnet 321 generates a constant magnetic field, which is guided and concentrated to the pole teeth 323 by the pole shoes 322 on both sides. Due to the radial gap 324 between the pole shoes 322 and the conveyor shaft 23, a high-intensity magnetic circuit is formed at this location. The injected magnetofluid 325 is captured by this high-intensity magnetic field and firmly adheres to the radial gap 324 between the pole teeth 323 and the surface of the conveyor shaft 23, forming one or more liquid "O-ring" sealing rings. When the conveyor shaft 23 rotates, the liquid properties of the magnetofluid 325 allow it to maintain relative motion with the shaft surface, while simultaneously maintaining the integrity and stability of the sealing rings under the constraint of the high-intensity magnetic field, thereby achieving a dynamic rotational seal and effectively preventing the powder material in the granulator 1 cavity from leaking backwards along the conveyor shaft 23. The guide plate 312 is used to guide the magnetic fluid 325 to the radial gap 324 region when it is injected through the injection hole 311, so as to ensure that the magnetic fluid 325 can be accurately and uniformly filled into the sealing working area. In this embodiment, the magnetic fluid 325 is a stable colloidal solution composed of nano-sized iron oxide, fluorocarbon oil and surfactant.

[0022] The cooling structure 4 includes a cooling jacket 41, which surrounds the outside of the magnetic shielding shell 33, and the interior of the cooling jacket 41 is filled with coolant 42.

[0023] A miniature shaft 43 is installed on one side of the outer wall of the cooling jacket 41, and a permanent magnet impeller 44 is rotatably connected to one end of the miniature shaft 43.

[0024] The cooling jacket 41 is made of either stainless steel or plastic.

[0025] Specifically, the magnetic circuit assembly 32 generates heat during operation due to eddy current effects and friction with the rotating shaft. The coolant 42 within the cooling jacket 41 absorbs and removes this heat. To further improve cooling efficiency, the permanent magnet impeller 44 rotates around the micro-shaft 43 under the influence of an external rotating magnetic field. The rotation of the permanent magnet impeller 44 agitates the coolant 42, creating a forced circulation flow within the cooling jacket 41. This active circulation process disrupts the thermal boundary layer of the static coolant 42, significantly enhancing the heat exchange efficiency between the coolant 42 and the wall of the cooling jacket 41. This results in faster and more uniform cooling of the sealing mechanism 3, ensuring that the operating temperature of the magnetic fluid 325 remains stable within its optimal performance range. The cooling jacket 41 is made of non-magnetic or low-magnetic materials such as stainless steel or plastic to avoid shielding or interfering with the magnetic field of the magnetic circuit assembly 32. In this embodiment, the coolant 42 used is water.

[0026] Working principle: The magnetic circuit assembly 32 generates a constant magnetic field through the annular permanent magnet 321, which is guided and concentrated to the pole teeth 323 by the symmetrically arranged pole shoes 322. A high-intensity magnetic field region is formed in the radial gap 324 between the pole teeth 323 and the surface of the rotating conveyor shaft 23. The injected magnetic fluid 325 is captured by this magnetic field and firmly bound in this radial gap 324, forming one or more liquid sealing rings. This sealing ring can maintain a dynamic sealing state when the conveyor shaft 23 rotates, effectively preventing the reverse leakage of powder material in the granulator 1 cavity. At the same time, in order to ensure that the magnetic fluid 325 operates in the optimal temperature range, the cooling jacket 41 surrounding the magnetic shielding shell 33 is filled with coolant 42. The permanent magnet impeller 44 installed in the cooling jacket 41 rotates under external drive, pushing the coolant 42 to form a forced circulation, effectively destroying the thermal boundary layer, significantly enhancing the heat exchange efficiency, and continuously removing the heat generated by the magnetic circuit assembly 32 during operation, ensuring the long-term stable operation of the sealing mechanism 3.

[0027] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A sealing mechanism for a dry granulator, comprising a granulator (1), characterized in that: A conveying structure (2) is installed on one side of the outer wall of the pellet mill (1), which conveys the material into the pellet mill (1) by a screw conveyor. A sealing mechanism (3) is provided at one end of the inner side of the conveying structure (2), which seals the conveying structure (2). A cooling structure (4) is also provided outside the sealing mechanism (3), which cools the sealing mechanism (3). The conveying structure (2) includes a conveying pipe (21), one end of which is connected to the granulator (1), and the other end of which is fixedly connected to a conveying motor (22). The output end of the conveying motor (22) passes through the outer wall of the conveying pipe (21) and is fixedly connected to a conveying shaft (23). A conveying auger (24) is installed on the outside of the conveying shaft (23), and a feed inlet (25) is provided at the top of the conveying pipe (21).

2. The sealing mechanism for a dry granulation machine according to claim 1, characterized in that: The sealing mechanism (3) includes a sealing housing (31), which is installed on the outer wall of the conveying shaft (23). The sealing housing (31) is provided with a magnetic circuit assembly (32) inside. The magnetic circuit assembly (32) includes an annular permanent magnet (321) and a pair of pole shoes (322) symmetrically arranged on both sides of the annular permanent magnet (321). The pole shoes (322) are provided with pole teeth (323) on the outside. A radial gap (324) is formed between the pole teeth (323) and the surface of the conveying shaft (23). The radial gap (324) is filled with a magnetic fluid (325).

3. The sealing mechanism for a dry granulation machine according to claim 2, characterized in that: The sealed housing (31) is further provided with a magnetic shielding shell (33), and the magnetic circuit assembly (32) is disposed inside the magnetic shielding shell (33). The material of the magnetic shielding shell (33) is austenitic stainless steel.

4. A sealing mechanism for a dry granulation machine according to claim 3, characterized in that: The cooling structure (4) includes a cooling jacket (41) that surrounds the outside of the magnetic shield (33) and is filled with coolant (42).

5. A sealing mechanism for a dry granulation machine according to claim 4, characterized in that: A miniature shaft (43) is installed on one side of the outer wall of the cooling jacket (41), and a permanent magnet impeller (44) is rotatably connected to one end of the miniature shaft (43).

6. A sealing mechanism for a dry granulation machine according to claim 4, characterized in that: The cooling jacket (41) is made of either stainless steel or plastic.

7. A sealing mechanism for a dry granulation machine according to claim 2, characterized in that: A liquid injection hole (311) is provided on one side of the outer wall of the sealing housing (31), and a guide plate (312) connected to the inner wall of the sealing housing (31) is provided below the liquid injection hole (311).

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