A bottom-mounted magnetic stirring device

Abstract

This application discloses a bottom-mounted magnetic stirring device suitable for installation at the bottom of a mixing tank. The magnetic stirring device includes an isolation sleeve and an impeller assembly. The isolation sleeve is installed at the bottom of the mixing tank and is arranged vertically. A drive shaft is disposed inside the isolation sleeve. The impeller assembly is sleeved outside the isolation sleeve and disposed inside the mixing tank. The drive shaft is adapted to drive the impeller assembly to rotate via magnetic transmission. The impeller assembly is axially movably connected to the isolation sleeve. The impeller assembly is adapted to drive the material in the middle of the mixing tank to move downward. A limiting structure is provided on the isolation sleeve, and the limiting structure is located on the upper part of the impeller assembly. It is adapted to generate a downward limiting force acting on the impeller assembly, thereby limiting the maximum upward displacement of the impeller assembly. One object of this application is to provide a magnetic stirring device that meets high hygiene standards, has low wear, and does not easily leave material residue.

Description

Technical Field

[0001] This application relates to the field of magnetic stirring, and in particular to a bottom-mounted magnetic stirring device. Background Technology

[0002] Currently, bottom-entry magnetic stirring devices are used in mixing tanks and installed at the bottom of the tank. The opening at the bottom of the mixing tank is sealed by an isolation sleeve. The outer side of the isolation sleeve is inside the mixing tank, and the inner side of the isolation sleeve is outside the mixing tank. A drive shaft is rotatably installed inside the isolation sleeve, and an impeller assembly is fitted on the outer side of the isolation sleeve. The drive shaft drives the impeller assembly to rotate through magnetic transmission, so that the impeller assembly can stir the material inside the mixing tank. The material inside the mixing tank can be liquid, solid particles, etc.

[0003] Traditional magnetic stirring devices typically drive the material in the middle of the mixing tank upwards, facilitating stirring. However, in actual use, magnetic stirring devices are prone to wear and tear, which can cause contamination of materials with high hygiene requirements (such as those in the pharmaceutical industry). Furthermore, material residues can easily remain on the magnetic stirring device, making cleaning difficult. These are problems that need to be solved by those skilled in the art. Summary of the Invention

[0004] One objective of this application is to provide a magnetic stirring device that meets high hygiene standards, has minimal axial wear, and minimizes material residue.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] A bottom-mounted magnetic stirring device is suitable for installation at the bottom of a mixing tank. The magnetic stirring device includes an isolation sleeve and an impeller assembly. The isolation sleeve is installed at the bottom of the mixing tank and is arranged vertically. A drive shaft is disposed within the isolation sleeve. The impeller assembly is sleeved outside the isolation sleeve and disposed inside the mixing tank. The drive shaft is adapted to drive the impeller assembly to rotate via magnetic transmission. The impeller assembly is axially movably connected to the isolation sleeve. The impeller assembly is adapted to drive material in the middle of the mixing tank to move downwards. A limiting structure is provided on the isolation sleeve, and the limiting structure is disposed on the upper part of the impeller assembly, adapted to generate a downward limiting force acting on the impeller assembly, thereby limiting the maximum upward displacement of the impeller assembly. It is easily understood that, driven by the impeller assembly, material in the middle of the mixing tank moves downwards, and material on the outside moves upwards, thus forming a circulation, facilitating the stirring process. Furthermore, the inside of the isolation sleeve is outside the mixing tank, and the outside of the isolation sleeve is inside the mixing tank. Magnetic drive is an existing technology in which the drive magnet on the drive shaft and the transmission magnet on the impeller assembly are adapted to generate a magnetic force that attracts each other. When the drive shaft rotates, due to the magnetic attraction, it can drive the transmission magnet fixed on the impeller assembly to rotate, thereby driving the impeller assembly to rotate.

[0007] The inventors of this application further analyze the reasons why existing magnetic stirring devices are prone to wear: magnetic stirring devices usually drive the material in the middle of the stirring tank to move upward, and this material will generate a downward impact force on the impeller assembly. This impact force will continue to increase as the stirring speed of the material increases. In addition, since the gravity of the impeller assembly is also downward, a limiting structure needs to be set on the isolation sleeve to bear the effects of gravity and impact force at the same time. As the stirring speed increases, the impact force will continue to increase, further aggravating the force on the limiting structure, thereby causing the limiting structure to wear and deform, which in turn contaminates the material or causes material residue to remain at the worn and deformed area, making cleaning difficult.

[0008] In addition, when bottom-in inclined stirring is used, the liquid moves upward in a spiral motion. The rotation can easily form a central inclined funnel-shaped vortex from the liquid surface downward. This vortex may seem to flow violently, but it is actually a circumferential flow with weak mass transfer performance. Moreover, it can easily bring gas from the gas phase space into the liquid.

[0009] Based on this, the inventors of this application have developed a bottom-entry magnetic stirring device, which is installed at the bottom of the stirring tank. The impeller assembly can drive the material in the middle of the stirring tank to move downward, thereby generating an upward impact force on the impeller assembly, which counteracts the gravity of the impeller assembly. This impact force increases continuously with the increase of stirring speed until it completely exceeds the gravity of the impeller assembly. At this point, a limiting structure generates a downward limiting force, thereby limiting the maximum upward displacement of the impeller assembly. This effectively reduces the force acting on the limiting structure during use (this force is the same in magnitude as the downward limiting force generated by the limiting structure, but in the opposite direction, belonging to the action-reaction relationship), thereby reducing the stress on the limiting structure, thus reducing the wear and deformation of the limiting structure, reducing the possibility of material contamination, and reducing the problem of material residue at the wear and deformation sites causing cleaning difficulties.

[0010] In addition, the bottom-entry magnetic stirring device of this application drives the liquid to move upward in a spiral, forming a flow field with strong mass transfer performance, thereby increasing the uniformity of liquid stirring.

[0011] Further preferably, the top of the isolation sleeve has a sliding post protruding upward along the axial direction, and the sliding post is fixedly connected to the isolation sleeve. The impeller assembly includes a transmission seat and an impeller body. The impeller body and the transmission seat are fixedly connected and arranged in the vertical direction. The transmission seat is sleeved on the outside of the isolation sleeve. The drive shaft drives the transmission seat to drive through magnetic transmission, and drives the impeller body to rotate, thereby driving the material in the middle of the mixing tank to move downward. The impeller body is sleeved on the outside of the sliding post, and the inner wall of the impeller body is adapted to abut against the outer peripheral surface of the sliding post and restrict the radial displacement of the impeller body.

[0012] In a further preferred embodiment, a limiting cap is provided on the top of the sliding column protruding radially outward, and the lower end face of the limiting cap is adapted to abut against the upper end face of the impeller body and limit the maximum upward displacement of the impeller body along the axial direction.

[0013] In a further preferred embodiment, a first magnet is provided in the middle of the limiting cap, and a second magnet is provided on the impeller body. The first magnet and the second magnet are adapted to generate a magnetic force that repels each other in the vertical direction, thereby generating a downward limiting force acting on the impeller body.

[0014] In a further preferred embodiment, a first magnet is provided on the outer periphery of the limiting cap, and a second magnet is provided on the impeller body. The first magnet and the second magnet are adapted to generate a magnetic force that repels each other in the vertical direction, thereby generating a downward limiting force acting on the impeller body.

[0015] Further preferably, the transmission seat has transmission magnets distributed circumferentially inside, and the drive shaft has drive magnets distributed circumferentially outside. The drive magnets drive the transmission magnets to rotate by magnetic force transmission, thereby driving the transmission seat to rotate. The transmission seat has a weight-reducing groove arranged circumferentially on its upper side. The weight-reducing groove is located outside the transmission magnets, and the groove opening faces downward. A sealing block is also fixedly connected to the bottom of the transmission seat. The sealing block is adapted to close the groove opening of the weight-reducing groove.

[0016] Further preferably, the bottom of the isolation sleeve expands radially outward to form a mounting portion, the upper part of the mounting portion penetrates into the mixing tank, the lower part of the mounting portion is adapted to close the bottom opening of the mixing tank, a third magnet is provided on the upper part of the mounting portion, and a fourth magnet matching the third magnet is provided on the lower part of the transmission seat. The third magnet and the fourth magnet are adapted to generate a repulsive magnetic force between each other in the vertical direction, and to make the impeller assembly suspend relative to the isolation sleeve.

[0017] Further preferably, the material inside the mixing tank is a liquid, and when the impeller assembly is stationary relative to the mixing tank, the weight of the impeller assembly is controlled to be equal to the buoyancy of the liquid on the impeller assembly.

[0018] Further preferably, the transmission base has transmission magnets distributed circumferentially inside, and the drive shaft has drive magnets distributed circumferentially outside. The drive magnets drive the transmission magnets to rotate through magnetic transmission, thereby driving the transmission base to rotate. When the impeller assembly is stationary relative to the mixing tank, the transmission magnets and the drive magnets are axially misaligned, and the drive magnets are located on the upper part of the transmission magnets. The impeller assembly is suspended relative to the isolation sleeve under the magnetic force of the transmission magnets and the drive magnets.

[0019] Preferably, the sliding column is integrally formed with the isolation sleeve or is fixedly connected by threads.

[0020] Compared with the prior art, the beneficial effects of this application are as follows:

[0021] (1) Since the bottom-entry magnetic stirring device is set at the bottom of the mixing tank, the impeller assembly can drive the material in the middle of the mixing tank to move downward, so that the material can generate an upward impact force on the impeller assembly and counteract the gravity of the impeller assembly. The impact force will increase continuously as the stirring speed increases until it completely exceeds the gravity of the impeller assembly. At this time, the limiting structure generates a downward limiting force, thereby limiting the maximum upward displacement of the impeller assembly. This effectively reduces the force acting on the limiting structure during use (this force is the same in magnitude as the downward limiting force generated by the limiting structure, but opposite in direction, and belongs to the relationship of action and reaction forces), thereby reducing the force on the limiting structure, thereby reducing the wear and deformation of the limiting structure, reducing the possibility of material contamination, and reducing the problem of material residue causing cleaning difficulties at the wear and deformation site.

[0022] (2) In addition, the bottom-entry magnetic stirring device of this application drives the liquid to move upward in a spiral, forming a flow field with strong mass transfer performance, thereby increasing the uniformity of liquid stirring. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of one embodiment of the magnetic stirring device of this application, showing the impeller assembly;

[0024] Figure 2 An exploded view of one embodiment of the magnetic stirring apparatus of this application, showing the isolation sleeve;

[0025] Figure 3a This is a schematic diagram of Embodiment 1 of the magnetic stirring device of this application. The dashed lines show the flow direction of the material in the middle of the stirring tank, and the limiting structure is mechanical limiting.

[0026] Figure 3b This is a schematic diagram of a first embodiment of the magnetic stirring device of this application, showing the impeller assembly moving upward;

[0027] Figure 4 This is a partial enlarged view of position A in Embodiment 1 of the magnetic stirring device of this application, showing the impeller body contacting the limiting cap;

[0028] Figure 5 This is a schematic diagram of Embodiment 2 of the magnetic stirring device of this application, showing that the limiting structure is a magnetic limiting structure;

[0029] Figure 6 This is a schematic diagram of Embodiment 3 of the magnetic stirring device of this application, showing that the limiting structure is another type of magnetic limiting;

[0030] Figure 7 This is a schematic diagram of Embodiment 4 of the magnetic stirring device of this application, showing the separate arrangement of the sliding column 12 and the isolation sleeve 1;

[0031] Figure 8 This is a schematic diagram of one embodiment of the magnetic stirring device of this application, showing a weight reduction tank;

[0032] Figure 9 This is a schematic diagram of one embodiment of the magnetic stirring device of this application, showing the drive magnet and the transmission magnet being offset along the axial direction.

[0033] In the figure: 1. Isolation sleeve; 11. Limiting structure; 12. Sliding column; 121. Limiting cap; 1211. First magnet; 13. Mounting part; 131. Third magnet; 2. Impeller assembly; 21. Transmission seat; 211. Weight reduction groove; 212. Transmission magnet; 213. Sealing block; 214. Fourth magnet; 22. Impeller body; 221. Second magnet; 100. Drive shaft; 101. Drive magnet; 200. Mixing tank. Detailed Implementation

[0034] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0035] In the description of this application, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0036] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0037] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0038] The inventors of this application further analyzed the reasons why existing magnetic stirring devices are prone to wear: magnetic stirring devices usually drive the material in the middle of the stirring tank 200 to move upward, and this material will generate a downward impact force on the impeller assembly 2. This impact force will continue to increase as the stirring speed of the material increases. In addition, since the gravity of the impeller assembly 2 is also downward, a limiting structure 11 needs to be set on the isolation sleeve 1 to bear the effects of gravity and impact force at the same time. As the stirring speed increases, the impact force will continue to increase, further aggravating the force on the limiting structure 11, thereby causing the limiting structure 11 to wear and deform, which in turn contaminates the material or causes material residue at the worn and deformed area, making cleaning difficult.

[0039] In addition, when bottom-in inclined stirring is used, the liquid moves upward in a spiral motion. The rotation can easily form a central inclined funnel-shaped vortex from the liquid surface downward. This vortex may seem to flow violently, but it is actually a circumferential flow with weak mass transfer performance. Moreover, it can easily bring gas from the gas phase space into the liquid.

[0040] Based on this, the inventors of this application have developed a bottom-mounted magnetic stirring device suitable for installation at the bottom of a stirring tank 200, one embodiment of which is, for example... Figures 1 to 9 As shown, the magnetic stirring device includes an isolation sleeve 1 and an impeller assembly 2. The isolation sleeve 1 is installed at the bottom of the mixing tank 200 and is arranged in the vertical direction. A drive shaft 100 is provided inside the isolation sleeve 1. The impeller assembly 2 is sleeved outside the isolation sleeve 1 and is arranged inside the mixing tank 200. The drive shaft 100 is adapted to drive the impeller assembly 2 to rotate by magnetic transmission. Specifically, the impeller assembly 2 includes a transmission seat 21 and an impeller body 22. The impeller body 22 and the transmission seat 21 are fixedly connected and arranged in the vertical direction. The transmission seat 21 is sleeved outside the isolation sleeve 1, and the inner edge of the transmission seat 21 is... A drive magnet 212 is circumferentially distributed, and a drive magnet 101 is circumferentially distributed around the outer periphery of the drive shaft 100. The drive magnet 101 drives the drive magnet 212 to rotate via magnetic transmission, thereby causing the drive seat 21 to rotate. The impeller assembly 2 is axially movably connected to the isolation sleeve 1. The impeller assembly 2 is suitable for driving the material in the middle of the mixing tank 200 to move downward. The isolation sleeve 1 is provided with a limit structure 11, which is located on the upper part of the impeller assembly 2 and is suitable for generating a downward limiting force acting on the impeller assembly 2, thereby limiting the maximum upward displacement of the impeller assembly 2. It is easy to understand that under the drive of the impeller assembly 2, the material in the middle of the mixing tank 200 moves downward (e.g., ...). Figure 3a (As indicated by the middle arrow), the external material moves upwards, thus forming a circulation, which facilitates the mixing process. Additionally, as... Figure 3aAs shown, the interior of the isolation sleeve 1 is located outside the mixing tank 200, and the exterior of the isolation sleeve 1 is located inside the mixing tank 200. Magnetic drive is a prior art technique, in which the drive magnet 101 on the drive shaft 100 and the transmission magnet 212 on the impeller assembly 2 are adapted to generate a mutually attractive magnetic force. When the drive shaft 100 rotates, due to the magnetic attraction, it can drive the transmission magnet 212 fixed on the impeller assembly 2 to rotate, thereby driving the impeller assembly 2 to rotate.

[0041] It is worth mentioning that the downward movement of material in the middle of the mixing tank 200 controlled by the impeller assembly 2 can be achieved by controlling the blade tilt angle and the rotation direction of the impeller assembly 2, such as... Figure 1 As shown, the impeller assembly 2 rotates clockwise, and the blade tilts in the same direction as the rotation, thereby enabling the impeller assembly 2 to drive the material in the middle of the mixing tank 200 to move downward.

[0042] Because the impeller assembly 2 can drive the material in the middle of the mixing tank 200 to move downward, these materials can generate an upward impact force on the impeller assembly 2, which counteracts the gravity of the impeller assembly 2. This impact force will continue to increase as the mixing speed increases until it completely exceeds the gravity of the impeller assembly 2. At this time, the limiting structure 11 generates a downward limiting force, thereby limiting the maximum upward displacement of the impeller assembly 2. This effectively reduces the force acting on the limiting structure 11 during use (this force is the same in magnitude as the downward limiting force generated by the limiting structure 11, but in the opposite direction, which is a relationship between action and reaction forces). This reduces the stress on the limiting structure 11, thereby reducing the wear and deformation of the limiting structure 11, reducing the possibility of material contamination, and reducing the problem of material residue at the wear and deformation sites causing cleaning difficulties. This meets the production requirements of sanitary materials and avoids the problem of material contamination. It is easy to understand that, assuming the impeller assembly 2 rotates at the same speed, the driving material moves upward or downward at the same speed, thus the impact force of the material on the impeller assembly 2 is the same in magnitude but opposite in direction. When the impact force of the material on the impeller assembly 2 is downward, the limiting force of the limiting component is approximately equal to the magnitude of the impact force of the material on the impeller assembly plus the magnitude of gravity. When the impact force of the material on the impeller assembly 2 is upward, the limiting force of the limiting component is approximately equal to the magnitude of the impact force of the material on the impeller assembly minus the magnitude of gravity. When the impact force is the same, it is obvious that the limiting force of the limiting component is smaller when the impact force of the material on the impeller assembly 2 is upward.

[0043] Further supplementing the principle of magnetism makes the forces acting on materials equal.

[0044] It is worth mentioning that, under the condition of working with liquid materials, the impeller assembly 2 will also be affected by the buoyancy of the liquid during use. The buoyancy will offset the effect of gravity, but it will not affect the effect of reducing the force on the limiting structure 11 in this application.

[0045] In addition, the bottom-entry magnetic stirring device of this application drives the liquid to move upward in a spiral, forming a flow field with strong mass transfer performance, thereby increasing the uniformity of liquid stirring.

[0046] Further optimization, such as Figures 3a to 3b As shown, a sliding column 12 is provided on the top of the isolation sleeve 1 along the axial direction and is fixedly connected to the isolation sleeve 1. The drive shaft 100 drives the transmission seat 21 through magnetic transmission and drives the impeller body 22 to rotate, thereby driving the material in the middle of the mixing tank 200 to move downward. The impeller body 22 is sleeved on the outside of the sliding column 12, and the inner wall of the impeller body 22 is adapted to abut against the outer peripheral surface of the sliding column 12 and restrict the radial displacement of the impeller body 22.

[0047] A sliding post 12 is provided on the top of the isolation sleeve 1, protruding upward along the axial direction. The sliding post 12 is fixedly connected to the isolation sleeve 1, and the impeller body 22 is sleeved on the outside of the sliding post 12. The inner wall of the impeller body 22 is adapted to abut against the outer circumferential surface of the sliding post 12, which can limit the radial displacement of the impeller body 22 and prevent the impeller body 22 from radially moving during rotation, causing unnecessary wear. Since a transmission magnet 212 is provided inside the transmission base 21 and a drive magnet 101 is provided on the drive shaft 100, the transmission magnet 212 and the drive magnet 101 are in a magnetic meshing state. Therefore, the radial displacement of the impeller assembly 2 can be limited to a certain extent by the transmission magnet 212 and the drive magnet 101. However, since the transmission magnet 212 and the drive magnet 101 are in magnetic transmission and there is no contact between them, they are easily disturbed by the material in the mixing tank 200 during the stirring process, causing unstable motion states such as radial movement, which leads to unnecessary wear. Therefore, by setting a sliding column 12 and making the inner wall of the impeller body 22 abut against the outer circumferential surface of the sliding column 12, the radial displacement of the impeller body 22 can be further significantly reduced.

[0048] It is also worth mentioning that lubricating sleeves can be used to further reduce axial friction while increasing radial restraint. Using lubricating sleeves can further reduce axial wear, enabling its use in high-hygiene environments.

[0049] Example 1: As Figures 3a to 4 As shown, a limit cap 121 protrudes radially outward from the top of the sliding column 12. The lower end face of the limit cap 121 is adapted to abut against the upper end face of the impeller body 22, limiting the maximum upward axial displacement of the impeller body 22. In this embodiment, the limiting structure 11 is the limit cap 121, which adopts the principle of mechanical limiting. When the impeller body 22 rotates and stirs the material, the flow direction of the material is as follows: Figure 3aAs indicated by the dashed arrow, the material will therefore generate an upward force acting on the impeller body 22, such as... Figure 3b As shown, this force counteracts the gravity of the impeller assembly 2 and increases with increasing rotational speed; when this force exceeds the gravity of the impeller assembly 2, the impeller assembly 2 will move upward, and the lower end face of the limiting cap 121 will abut against the upper end face of the impeller body 22. Figure 4 As shown, the impeller assembly 2 is restricted by the limiting cap 121 to prevent it from detaching upward from the sliding column 12. It is also worth mentioning that the limiting cap 121 can be threaded to the top of the sliding column 12, integrally formed with the sliding column 12, or fixedly connected to the top of the sliding column 12 by welding or other methods.

[0050] Example 2: Figure 5 As shown, a first magnet 1211 is disposed in the middle of the limiting cap 121, and a second magnet 221 is disposed on the impeller body 22. The first magnet 1211 and the second magnet 221 are adapted to generate a repulsive magnetic force between them in the vertical direction, thereby generating a downward limiting force acting on the impeller body 22. In this embodiment, the limiting structure 11 is a magnetic limiting method, specifically as follows: Figure 5 As shown, a first magnet 1211 is disposed in the middle of the limiting cap 121, with the N pole of the first magnet 1211 facing downwards. A second magnet 221 is disposed on the impeller body 22, with the N pole of the second magnet 221 facing upwards. A repulsive magnetic force is generated between the first magnet 1211 and the second magnet 221 in the vertical direction. Alternatively, the S pole of the first magnet 1211 can be disposed with its downward-facing pole, and the S pole of the second magnet 221 on the impeller body 22 can be disposed with its upward-facing pole. This creates a repulsive force between the first magnet 1211 and the second magnet 221 in the vertical direction, thereby applying a downward limiting force to the impeller body 22 and preventing the impeller body 22 from moving upwards and detaching from the sliding column 12.

[0051] Example 3: Figure 6As shown, a first magnet 1211 is provided on the outer periphery of the limiting cap 121, and a second magnet 221 is provided on the impeller body 22. The first magnet 1211 and the second magnet 221 are adapted to generate a repulsive magnetic force in the vertical direction, thereby generating a downward limiting force acting on the impeller body 22. In this embodiment, the limiting structure 11 adopts a magnetic limiting method. Specifically, the first magnet 1211 is provided on the outer periphery of the limiting cap 121, with the N pole of the first magnet 1211 facing downward, and the second magnet 221 is provided on the impeller body 22, with the N pole of the second magnet 221 facing upward. A repulsive magnetic force is generated between the first magnet 1211 and the second magnet 221 in the vertical direction. Alternatively, the S pole of the first magnet 1211 can be set downwards, and the S pole of the second magnet 221 on the impeller body 22 can be set upwards, forming a repulsive force in the vertical direction between the first magnet 1211 and the second magnet 221, thereby applying a downward limiting force to the impeller body 22 and preventing the impeller body 22 from moving upwards and detaching from the sliding column 12.

[0052] By not setting the first magnet 1211 on the outer periphery of the limiting cap 121, the positions of the first magnet 1211 and the second magnet 221 can be better aligned, so that the magnetic forces that repel each other in the vertical direction can act better on the impeller body 22, thereby limiting the displacement of the impeller body 22.

[0053] Further optimization, such as Figure 8 As shown, a weight-reducing groove 211 is provided circumferentially on the transmission base 21. The weight-reducing groove 211 is located on the outside of the transmission magnet 212, and the groove opening of the weight-reducing groove 211 faces downward. A sealing block 213 is also fixedly connected to the bottom of the transmission base 21, and the sealing block 213 is suitable for sealing the groove opening of the weight-reducing groove 211. It is worth mentioning that the weight-reducing groove 211 can be provided not only on the transmission base 21, but also on the impeller body 22.

[0054] Setting a weight-reducing groove 211 on the transmission base 21 and positioning it on the outside of the transmission magnet 212 has two advantages: First, by setting the weight-reducing groove 211, the weight of the impeller assembly 2 can be reduced, making it easier to achieve a balance between buoyancy and gravity and reducing the force on the limiting structure 11. Second, since the weight-reducing groove 211 is a cavity, it can serve as a heat insulation function. In actual use, since the impeller assembly 2 and the drive shaft 100 adopt a non-contact magnetic transmission method, the magnetic transmission method may cause the temperature of the drive magnet 101 and the transmission magnet 212 to rise. Setting the weight-reducing groove 211 can prevent this temperature from being transmitted to the material in the mixing tank 200 through the transmission base 21, causing the material temperature to rise and thus affecting the mixing result. Especially for processes with strict temperature control, setting the weight-reducing groove 211 can effectively isolate the temperature transmission, improve the quality of production, and reduce unnecessary temperature rise.

[0055] Example 4: Figure 7 As shown, the sliding post 12 and the isolation sleeve 1 are fixedly connected by threads. This fixed connection increases the versatility of the original isolation sleeve 1. A threaded hole is provided on the conventional isolation sleeve 1, and the sliding post 12 is used for threaded connection, thus achieving a fixed connection between the sliding post 12 and the isolation sleeve 1, reducing the hassle of additional material preparation and processing. Of course, the sliding post 12 and the isolation sleeve 1 can also be integrally formed, such as... Figures 3a to 6 As shown.

[0056] Further preferred embodiments, such as Figure 7 As shown, the bottom of the isolation sleeve 1 expands radially outward to form a mounting part 13. The upper part of the mounting part 13 penetrates into the mixing tank 200, and the lower part of the mounting part 13 is adapted to close the bottom opening of the mixing tank 200. When the drive shaft 100 is not started, the impeller assembly 2 is subjected to gravity and buoyancy, which causes it to move downward. This results in the bottom of the transmission seat 21 contacting the upper part of the mounting part 13, causing greater friction between the transmission seat 21 and the mounting part 13 during startup, resulting in wear. Therefore, a third magnet 131 is provided on the upper part of the mounting part 13, and a fourth magnet 214 matching the third magnet 131 is provided on the lower part of the transmission seat 21. The third magnet 131 and the fourth magnet 214 are adapted to generate a repulsive magnetic force in the vertical direction, and make the impeller assembly 2 suspended relative to the isolation sleeve 1.

[0057] In this specific embodiment, the N pole of the third magnet 131 can be positioned upwards, and the N pole of the fourth magnet 214 can be positioned downwards, thereby generating a repulsive force between the third magnet 131 and the fourth magnet 214 in the vertical direction. Similarly, the S pole of the third magnet 131 can be positioned upwards, and the N pole of the fourth magnet 214 can be positioned downwards, thereby generating a repulsive force between the third magnet 131 and the fourth magnet 214 in the vertical direction. This repulsive force allows the impeller assembly 2 to be suspended relative to the isolation sleeve 1 when it is stationary relative to the mixing tank 200, thereby reducing the friction between the impeller assembly 2 and the mounting part 13, thus reducing wear and preventing material contamination or material residue.

[0058] Further preferably, the material inside the mixing tank 200 is a liquid. When the impeller assembly 2 is stationary relative to the mixing tank 200, the weight of the impeller assembly 2 is equal to the buoyancy of the liquid on the impeller assembly 2. The stationary state includes circumferential and axial stationary states. In this specific embodiment, that is, when the drive shaft 100 is in a non-activated state, the impeller assembly 2 can be in both axial and circumferential stationary states relative to the mixing tank 200. Additionally, since the density (ρ) of the liquid inside the mixing tank 200 is generally equal to 1 g / cm³, the impeller assembly 2 is stationary. 3Therefore, the material of the impeller assembly 2 can be a non-metallic material with high strength. The weight reduction groove 211 is used to make the weight of the impeller assembly 2 equal to the buoyancy of the liquid on the impeller assembly 2. This allows the impeller assembly 2 to be suspended relative to the isolation sleeve 1 when the impeller assembly 2 is not started, thereby avoiding the problem of excessive friction between the impeller assembly 2 and the isolation sleeve 1.

[0059] Further optimization, such as Figure 9 As shown, a transmission magnet 212 is distributed circumferentially inside the transmission base 21, and a drive magnet 101 is distributed circumferentially outside the drive shaft 100. When the impeller assembly 2 is stationary relative to the mixing tank 200, the transmission magnet 212 and the drive magnet 101 are offset in the axial direction, and the drive magnet 101 is located above the transmission magnet 212. Under the magnetic force of the transmission magnet 212 and the drive magnet 101, the impeller assembly 2 is suspended relative to the isolation sleeve 1.

[0060] By axially misaligning the transmission magnet 212 and the drive magnet 101, with the drive magnet 101 positioned above the transmission magnet 212, the isolation sleeve 1 can be suspended by the magnetic force of the drive magnet 101 and the transmission magnet 212 (the two are in a magnetic attraction state), thereby reducing the friction between the impeller assembly 2 and the isolation sleeve 1 during startup. Furthermore, in actual use, as the rotational speed of the impeller assembly 2 increases, the upward impact force generated by the material of the mixing tank 200 on the impeller assembly 2 also increases, forcing the impeller assembly 2 to move upward. This causes the drive magnet 101 and the transmission magnet 212 to axially align, increasing the magnetic coupling force (attraction) between them. Therefore, when the impeller assembly 2 rotates, the driving force through the drive shaft 100 can be increased, thereby increasing the torque output through the impeller assembly 2.

[0061] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A bottom-mounted magnetic stirring device, suitable for installation at the bottom of a mixing tank, the magnetic stirring device comprising an isolation sleeve and an impeller assembly, the isolation sleeve being installed at the bottom of the mixing tank and arranged vertically, and a drive shaft being disposed within the isolation sleeve, the impeller assembly being sleeved outside the isolation sleeve and disposed inside the mixing tank, the drive shaft being adapted to drive the impeller assembly to rotate via magnetic transmission, characterized in that: The impeller assembly is axially and movably connected to the isolation sleeve. The impeller assembly is adapted to drive the material in the middle of the mixing tank to move downward and drive the liquid to move upward in a spiral motion. The isolation sleeve is provided with a limiting structure, which is located on the upper part of the impeller assembly and is adapted to generate a downward limiting force acting on the impeller assembly to limit the maximum upward displacement of the impeller assembly.

2. The bottom-entry magnetic stirring device as described in claim 1, characterized in that: The top of the isolation sleeve has a sliding post protruding upward along the axial direction, and the sliding post is fixedly connected to the isolation sleeve. The impeller assembly includes a transmission seat and an impeller body. The impeller body and the transmission seat are fixedly connected and arranged in the vertical direction. The transmission seat is sleeved on the outside of the isolation sleeve. The drive shaft drives the transmission seat to drive through magnetic transmission, and drives the impeller body to rotate, thereby driving the material in the middle of the mixing tank to move downward. The impeller body is sleeved on the outside of the sliding post, and the inner wall of the impeller body is adapted to abut against the outer peripheral surface of the sliding post and restrict the radial displacement of the impeller body.

3. The bottom-entry magnetic stirring device as described in claim 2, characterized in that: A limit cap is provided on the top of the sliding column that protrudes radially outward. The lower end face of the limit cap is adapted to abut against the upper end face of the impeller body and limit the maximum upward displacement of the impeller body along the axial direction.

4. The bottom-entry magnetic stirring device as described in claim 3, characterized in that: A first magnet is provided in the middle of the limiting cap, and a second magnet is provided on the impeller body. The first magnet and the second magnet are adapted to generate a magnetic force that repels each other in the vertical direction, thereby generating a downward limiting force acting on the impeller body.

5. The bottom-entry magnetic stirring device as described in claim 3, characterized in that: The outer periphery of the limiting cap is provided with a first magnet, and the impeller body is provided with a second magnet. The first magnet and the second magnet are adapted to generate a magnetic force that repels each other in the vertical direction, thereby generating a downward limiting force acting on the impeller body.

6. The bottom-entry magnetic stirring device as described in claim 2, characterized in that: The transmission base has transmission magnets distributed circumferentially inside, and drive magnets are distributed circumferentially on the outer periphery of the drive shaft. The drive magnets drive the transmission magnets to rotate by magnetic force transmission, thereby driving the transmission base to rotate. The transmission base has a weight-reducing groove arranged circumferentially on the upper side. The weight-reducing groove is located on the outer side of the transmission magnets, and the groove opening is facing downward. A sealing block is also fixedly connected to the bottom of the transmission base. The sealing block is adapted to close the groove opening of the weight-reducing groove.

7. The bottom-entry magnetic stirring device as described in claim 2, characterized in that: The bottom of the isolation sleeve expands radially outward to form a mounting portion. The upper part of the mounting portion penetrates into the mixing tank, and the lower part of the mounting portion is adapted to close the bottom opening of the mixing tank. A third magnet is provided on the upper part of the mounting portion, and a fourth magnet matching the third magnet is provided on the lower part of the transmission seat. The third magnet and the fourth magnet are adapted to generate a repulsive magnetic force between them in the vertical direction, so that the impeller assembly is suspended relative to the isolation sleeve.

8. The bottom-entry magnetic stirring device as described in claim 2, characterized in that: The material inside the mixing tank is a liquid. When the impeller assembly is stationary relative to the mixing tank, the weight of the impeller assembly is controlled to be equal to the buoyancy of the liquid on the impeller assembly.

9. A bottom-entry magnetic stirring device as described in claim 2, characterized in that: The transmission base has transmission magnets distributed circumferentially inside, and the drive shaft has drive magnets distributed circumferentially outside. The drive magnets drive the transmission magnets to rotate through magnetic transmission, thereby driving the transmission base to rotate. When the impeller assembly is stationary relative to the mixing tank, the transmission magnets and the drive magnets are axially misaligned, and the drive magnets are located on the upper part of the transmission magnets. The impeller assembly is suspended relative to the isolation sleeve under the magnetic force of the transmission magnets and the drive magnets.

10. A bottom-entry magnetic stirring device as described in claim 2, characterized in that: The sliding column is integrally formed with the isolation sleeve or is fixedly connected by threads.

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