Compact ultrathin electromagnetic pump

Abstract

The utility model discloses a compact ultrathin electromagnetic pump, including magnet, pump case unit and magnetic shell, said pump case unit includes metal electrode, metal joint and metal electrode and metal joint integrated injection moulding plastic pump case, the plastic pump case is provided with the internal flow channel, the two metal electrode is located in the internal flow channel both sides, the magnetic shell is located in the internal flow channel, and the magnetic shell is located in the internal flow channel. The two metal connectors are located at the two ends of the plastic pump shell and are in butt joint with the two ends of the inner flow channel, the magnet is arranged on the plastic pump shell, and the plastic pump shell is sleeved with the magnetic conduction shell. The electromagnetic pump is reasonable in structural design, the plastic pump shell is formed through injection molding, the inner flow channel is formed in the plastic pump shell, the metal electrodes are arranged on the two sides of the inner flow channel, the metal connectors are in butt joint with the two ends of the inner flow channel, the magnets are located at the upper position and the lower position of the inner flow channel and form a magnetic circuit through the magnetic conduction shell, the structure of the electromagnetic pump is greatly simplified, and production and manufacturing are easy. The production efficiency is improved and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of electromagnetic pumps, in particular to a compact ultra-thin electromagnetic pump. Background Art

[0002] With the advancement of technology, the power consumption of portable electronic devices is getting higher and higher, and the heat generated is getting higher and higher. How to transfer heat from the heat source to the heat sink fins is becoming more and more of a bottleneck in the design of heat dissipation modules. Common high-density heat transfer solutions include phase change heat transfer, such as flattened heat pipes and temperature equalizers; there are also single-phase liquid cooling, such as water cooling loop solutions and liquid metal loop solutions.

[0003] The measured results show that the total temperature rise of the liquid metal loop is significantly better than that of the water cooling loop. For example, for a 160W notebook cooling module, when other components are the same, the maximum temperature of the CPU is more than 10° lower when the liquid metal loop is used than when the water cooling loop is used, and the liquid metal loop has a better cooling effect.

[0004] Therefore, compared with the water-cooled loop, the liquid metal loop has a huge advantage. However, since the dynamic viscosity of liquid metal is about 4-6 times that of water, the liquid metal cannot be driven by a conventional fluid mechanical pump, but can only be driven by an electromagnetic pump. Based on the driving principle, electromagnetic pumps can be divided into conductive electromagnetic pumps and inductive electromagnetic pumps. Due to space limitations, inductive electromagnetic pumps are large in size and are unlikely to be placed in portable electronic devices, so micro electromagnetic pumps generally use conductive electromagnetic pumps. Since 2004, there have been a variety of conductive electromagnetic pump designs.

[0005] For example, the utility model patent application with publication number "CN115842461A" and titled "A Permanent Magnet DC Conductive Electromagnetic Pump" discloses a permanent magnet DC conductive electromagnetic pump, including a pipeline, two electrodes, a permanent magnet combination, two groups of pipeline mounting components and two bakelite boards, one group of the pipeline mounting components is arranged at the liquid inlet end for fixing the pipeline, and one group of the pipeline mounting components is arranged at the liquid outlet end for fixing the pipeline; the pipeline mounting components include two pipe clamps, two screws, four nuts and two insulation layers, and the two pipe clamps are arranged on both sides of the pipeline opposite to each other; the two ends of the screw are respectively connected to the opposite surfaces of the two magnetizers, each screw passes through the end of the pipe clamp, and the pipe clamp is fixed to the pipeline at the end of the pipe clamp by the two nuts. Each insulation layer is arranged between the pipe clamp and the pipeline, and the insulation layer is clamped on the surface of the pipeline by the pipe clamp. The two ends of the board surface of each bakelite board are respectively connected to the side surfaces of the two magnetizers, and each electrode passes through the bakelite board to connect to the surface of the pipeline. It has many parts, a complex structure, a high overall thickness, a large volume, and occupies a lot of space, which is not conducive to the miniaturization design of the equipment. Utility Model Content

[0006] In view of the above-mentioned shortcomings, the purpose of the utility model is to provide a compact ultra-thin electromagnetic pump.

[0007] In order to achieve the above purpose, the technical solution provided by the utility model is:

[0008] A compact ultra-thin electromagnetic pump comprises a magnet, a pump housing unit and a magnetic shell, wherein the pump housing unit comprises a metal electrode, a metal joint and a plastic pump housing which is integrally injection-molded and tightly combined and fixed with the metal electrode and the metal joint, wherein an inner flow channel is arranged in the plastic pump housing, two metal electrodes are located on both sides of the inner flow channel, two metal joints are located at both ends of the plastic pump housing and are connected to the two ends of the inner flow channel, the magnet is arranged on the plastic pump housing at the upper and lower positions corresponding to the inner flow channel, and the magnetic shell is sleeved on the plastic pump housing.

[0009] As a preferred solution of the utility model, the plastic pump housing is provided with a pouring hole connected to the inner flow channel, through which liquid metal is conveniently poured, effectively solving the problem that a hole needs to be opened in the metal flow channel to realize the pouring of liquid metal. After the liquid metal is poured through the pouring hole, a sealing member is provided on the pouring hole for sealing. For example, a rubber plug or a screw can be used to seal the pouring hole.

[0010] As a preferred solution of the utility model, the electrode plate portion of the metal electrode is located on the inner side wall of the inner flow channel, and the welding pad portion of the metal electrode is located on the outer surface of the plastic pump housing for easy connection.

[0011] As a preferred solution of the utility model, the pad portion of the metal electrode is located on the lower surface of the plastic pump housing and can be directly welded to the mainboard, making it convenient to connect and draw power from the mainboard, and can realize dual-channel and multi-channel power supply, reducing the difficulty of circuit module design.

[0012] As a preferred solution of the utility model, the cross-sectional dimensions of the inner flow channel are consistent with the cross-sectional dimensions of the channel of the metal joint, and the inner flow channel and the channel of the metal joint are mutually conductive. This is beneficial to core pulling and demolding, simplifies the manufacturing process, facilitates mass industrial production, reduces manufacturing costs, and is also beneficial to the flow of liquid metal. The inner flow channel is flat, and compared with a circular channel, a flat channel is more conducive to reducing the overall height.

[0013] As a preferred solution of the utility model, the surface of the metal joint is provided with evenly distributed indentations with a depth of 0.05 to 0.2 mm, so as to increase the physical bonding force between the metal joint and the plastic pump housing.

[0014] As a preferred solution of the utility model, the magnetic shell is U-shaped as a whole, and magnet cavities are provided on the upper and lower surfaces of the plastic pump shell corresponding to the position of the inner flow channel, and the magnet is arranged in the magnet cavity; two magnetic shells are symmetrically mounted on the plastic pump shell from both sides, and the opening of the magnet cavity is closed, passing through.

[0015] The beneficial effects of the utility model are as follows: the structure design of the utility model is reasonable, the plastic pump shell is formed by injection molding, and an inner flow channel is formed inside it, and metal electrodes are provided on both sides of the inner flow channel, and metal joints are connected at both ends, that is, the metal electrodes and metal joints are buried to fix them during the injection molding of the plastic pump shell, and the magnets are located at the upper and lower positions of the inner flow channel and form a magnetic circuit through the magnetic conductive shell, which greatly simplifies the structure of the electromagnetic pump and is easy to produce. In addition, a magnet cavity for fixing the magnet is provided on the plastic pump shell, which not only effectively reduces the overall height, but also allows the magnet to be closer to the inner flow channel. The cross-sectional dimensions of the inner flow channel of the plastic pump shell are consistent with the cross-sectional dimensions of the channel of the metal interface, which is conducive to core pulling and demolding, simplifies the manufacturing process, facilitates mass industrial production, reduces manufacturing costs, and is also conducive to the flow of liquid metal; the pad part of the metal electrode is located on the lower surface of the plastic pump shell, which not only reduces the occupied space, but also can be directly welded to the main board, and is resistant to high temperature, can be suitable for SMT assembly, can improve production efficiency, and reduce costs; in addition, the anti-corrosion effect is good and the service life is long.

[0016] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The three-dimensional structure of the utility model is shown in FIG. Figure 1 .

[0018] Figure 2 The three-dimensional structure of the utility model is shown in FIG. Figure 2 .

[0019] Figure 3 It is a cross-sectional structural schematic diagram of the utility model.

[0020] Figure 4 It is a schematic diagram of the exploded structure of the utility model.

[0021] Figure 5 It is a schematic diagram of the structure of the metal electrode in the utility model.

[0022] Figure 6 It is a structural schematic diagram of the middle frame in the utility model.

[0023] Figure 7 It is a schematic diagram of the structure of the utility model assembled with a metal runner.

[0024] Figure 8 for Figure 7 Schematic diagram of the local cross-sectional structure. DETAILED DESCRIPTION

[0025] See also Figure 1-Figure 6 The present embodiment provides a compact ultra-thin electromagnetic pump, which includes a magnetic shell 1, a magnet 2 and a pump shell unit, wherein the pump shell unit includes a metal electrode 3, a metal joint 4 and a plastic pump shell 5 which is integrally injection molded and tightly combined and fixed with the metal electrode 3 and the metal joint 4.

[0026] The plastic pump housing 5 is provided with an inner flow channel 51, which is flat and more conducive to reducing the overall height. Metal electrodes 3 are provided on both sides of the inner flow channel 51, and metal joints 4 are provided at both ends of the plastic pump housing 5 to be connected to the two ends of the inner flow channel 51. The magnet 2 is arranged on the plastic pump housing 5 at the upper and lower positions corresponding to the inner flow channel 51, and the magnetic conductive housing 1 is sleeved on the plastic pump housing 5.

[0027] The electrode plate portion of the metal electrode 3 is located on the inner side wall of the inner flow channel, and the pad portion 32 of the metal electrode 3 is located on the outer surface of the plastic pump housing 5 for easy connection. Preferably, the pad portion 32 of the metal electrode 3 is located on the lower surface of the plastic pump housing 5. Figure 5 The middle part of the metal electrode 3 is in a straight line to form a straight rod, and the two ends of the straight rod are provided with the pad part 32, which is exposed from the outer wall of the plastic pump shell 5 and extends to the bottom surface of the plastic pump shell 5, and the electrode plate part 31 is located at the center of the straight rod. Since the pad part 32 is located on the lower surface of the plastic pump shell 5, it can be directly welded to the main board, which is convenient for connection and power supply with the main board, and can realize dual-way and multi-way power supply, reducing the difficulty of circuit module design.

[0028] Preferably, the cross-sectional dimensions of the inner flow channel 51 are consistent with the cross-sectional dimensions of the channel of the metal joint 4. This is beneficial for core pulling and demolding, simplifies the manufacturing process, facilitates mass industrial production, reduces manufacturing costs, and is also beneficial for the flow of liquid metal. The surface of the metal joint 4 is embossed to form evenly distributed indentations, and the depth of the indentations is preferably 0.05 to 0.2 mm to increase the physical bonding force between the metal joint 4 and the plastic pump housing. An infusion hole 53 connected to the inner flow channel 51 is provided on the plastic pump housing 5. The infusion hole 53 is used to facilitate the infusion of liquid metal, which effectively solves the traditional problem of needing to open a hole in the metal flow channel 8 to achieve the infusion of liquid metal. After the liquid metal is infused through the infusion hole 53, a sealing member is provided on the infusion hole 53 for sealing. For example, the infusion hole 53 can be sealed with a rubber plug or a screw. The magnetic shell 1 is U-shaped as a whole, and magnet cavities are provided on the upper and lower surfaces of the plastic pump shell 5 at positions corresponding to the inner flow channel 51, and the magnet 2 is arranged in the magnet cavity 52; two magnetic shells 1 are symmetrically mounted on the plastic pump shell 5 from both sides, and the opening of the magnet cavity 52 is closed.

[0029] The production of a compact and ultra-thin electromagnetic pump includes the following steps:

[0030] (1) Processing and molding of the middle frame: prepare the middle frame material, preferably pure copper, oxygen-free copper or iron-copper alloy, such as T2 pure copper, TU2 oxygen-free copper and other grades, and then use metal powder injection molding (MIM), CNC processing + welding, metal 3D printing and other processes to make an integrated middle frame, preferably metal powder injection molding (MIM). The middle frame includes two metal electrodes 3 arranged relatively to the left and right positions and two metal joints 4 arranged relatively to the front and back positions; the two metal electrodes 3 are connected to the two metal joints 4 through a connector 7 to form an integrated structure. The two metal joints 4 and the two metal electrodes 3 are formed into a whole by injection molding at one time, and the combination is tight and the sealing effect is good, which greatly simplifies the assembly process of the electromagnetic pump, and the volume is small and thin. Taking a 160W module as an example, the structural design of the utility model can be achieved to 26mm×17mm×8mm, which can be perfectly placed in a portable electronic device such as a gaming notebook. Moreover, the metal injection molding process and the insert injection molding process are very mature, with good reliability and low mass production cost. Insert molding can significantly simplify the manufacturing process and reduce manufacturing costs.

[0031] (2) Surface treatment of the middle frame: The middle frame is subjected to surface treatment to enhance the bonding strength between the middle frame and the plastic pump housing; the surface treatment includes surface roughening treatment and silane coupling treatment performed in sequence. The surface roughening treatment is to increase the specific surface area of ​​the middle frame and enhance the physical bonding strength between the middle frame and the plastic pump housing 5. After the roughening treatment, dents with a depth of 0.05 to 0.2 mm are evenly distributed on the surface of the middle frame. The silane coupling treatment is performed to form a chemical adsorption film on the rough surface of the middle frame, so as to form a chemical bond between the middle frame and the surface of the injection molding body 5, thereby further enhancing the bonding strength between the middle frame and the injection molding body 5.

[0032] (3) Insert injection molding of the middle frame: prepare the material of the plastic pump casing 5, preferably glass fiber reinforced LCP, glass fiber reinforced PPA or glass fiber reinforced PPS, such as brand PPS+30GF. Since the plastic material contains glass fiber, the thermal expansion coefficient of the plastic pump casing 5 is close to that of the middle frame, which can further improve the bonding effect, and the plastic material is not easy to be plated, which brings convenience to the subsequent nickel plating process of the metal joint 4 and the metal electrode 3. Then, the insert injection molding process is used to form the plastic pump casing 5 that is tightly combined with the middle frame to obtain the pump casing unit. The main body of the traditional electromagnetic pump is mostly cast with epoxy resin, or bonded with structural adhesive. The thermal expansion coefficients of epoxy resin and structural adhesive are very different from those of copper. Therefore, when undergoing the low-temperature welding process, defects such as poor sealing are prone to occur. The plastic pump housing 5 of the utility model is made of glass fiber reinforced LCP, glass fiber reinforced PPA or glass fiber reinforced PPS, among which the short-term temperature resistance of glass fiber reinforced LCP can reach 280°C, the short-term temperature resistance of glass fiber reinforced PPA can reach 280°C, and the short-term temperature resistance of glass fiber reinforced PPS can reach 260°C; and the conventional low-temperature welding process is between 180-200°C, so it is compatible with the low-temperature welding process. The plastic pump housing 5 has an inner flow channel 51 that connects the two metal joints 4; the electrode plate portions 31 of the two metal electrodes 3 are located on the two side walls of the inner flow channel 51, and the pad portions 32 of the two metal electrodes 3 are located on the outer surface of the plastic pump housing 5. Preferably, the pad portions 32 of the metal electrodes 3 are located on the lower surface of the plastic pump housing 5. The electrode terminals of the traditional electromagnetic pump are located on both sides of the pump, and the size is large, so it is difficult to directly power the mainboard, so wires, terminals and other connecting devices are required, which not only complicates the structure of the electromagnetic pump, but also occupies a large space for the electrodes and wires. The pad portion 32 of the metal electrode 3 of the present invention is located on the lower surface, i.e., the bottom surface, of the plastic pump housing 5. Figure 5The middle part of the metal electrode 3 is in a straight line to form a straight rod part, and the two ends of the straight rod part are provided with the pad part 32, and the pad part 32 is exposed from the outer wall of the plastic pump shell 5 and extends to the bottom surface of the plastic pump shell 5, and the electrode plate part 31 is located at the center of the straight rod part. The pad part 32 is located on the lower surface of the plastic pump shell 5, which not only reduces the occupied space, but also can be directly welded to the main board. While achieving fixation, it is also convenient to connect and draw power from the main board, and can realize dual-channel and multi-channel power supply, reducing the difficulty of circuit module design. It can be applied to SMT assembly, which can further improve production efficiency and reduce costs. Magnet cavities 52 are provided on the upper and lower surfaces of the plastic pump shell 5 corresponding to the position of the inner flow channel 51.

[0033] (4) CNC machining of the pump housing unit: CNC machining is performed on the pump housing unit, and the connector 7 between the metal joint 4 and the metal electrode 3 is cut so that the two metal joints 4 and the two metal electrodes 3 are completely separated and insulated, and the inner flow channel 51 is machined. Because the inner flow channel 51 has a process draft angle, after machining, the cross-sectional dimensions of the inner flow channel 51 are consistent with the cross-sectional dimensions of the channel of the metal joint 4, so as to ensure the exhaust during the pouring of liquid metal and facilitate the flow of liquid metal; the pump channel of the traditional electromagnetic pump is designed to be flatter in the middle part in order to increase the Ampere force and bring the two magnets closer together, resulting in the inconsistency of the cross-sectional dimensions of the two ends of the pump channel with the middle part, that is, the height and width dimensions are inconsistent. When the width of the pump channel is wider than the width of the pump channel at both ends, it is difficult to pour. Because if the infusion structure is designed in the direction perpendicular to the magnet, then since the height of the pump channel below the magnet is the smallest, once the liquid metal level reaches the highest point of the pump channel, liquid metal can no longer be infused, and at this time there is still a lot of air left in the pipeline, that is, it is difficult to completely remove the air inside the metal channel 8, resulting in a low amount of liquid metal infusion; and the pump channel is difficult to process, and cannot be produced by injection molding, and can only be produced by small-scale casting, and the manufacturing cost is high. The utility model optimizes the inner channel 51, and designs the inner channel 51 and the channel of the metal joint 4 to have equal cross-sections, and only reserves a process draft angle in the inner channel 51, which is convenient for injection molding production and reduces costs. Then CNC processing is performed to remove the process draft angle. After processing, the cross-sectional dimensions of the inner channel 51 are consistent with the cross-sectional dimensions of the channel of the metal joint 4, so as to smoothly realize the design of the infusion structure on the electromagnetic pump body and simplify the complexity of the entire loop design.

[0034] Preferably, a perfusion hole 53 is processed on the upper surface or the lower surface of the plastic pump housing 5 by CNC, and the perfusion hole 53 is connected to the inner flow channel 51 to facilitate the perfusion of liquid metal, effectively solving the problem of traditionally needing to drill a hole in the metal flow channel 8 to achieve perfusion of liquid metal.

[0035] The metal electrode 3, metal joint 4 and metal flow channel 8 of the utility model are all made of pure copper. For this reason, in terms of corrosion protection, the metal flow channel 8 is preferably plated with nickel as a whole by a chemical nickel-phosphorus alloy process of low-phosphorus nickel to ensure that the metal flow channel 8 is resistant to liquid metal corrosion while maintaining good weldability with the metal fins. For the metal electrode 3 and the metal joint 4, it is preferred to use a chemical nickel-phosphorus alloy process of low-phosphorus nickel or a chemical nickel-boron alloy process of low-boron nickel to ensure good electrical conductivity. Since the metal material surface of the metal joint 4 and the metal flow channel 8 of the utility model in contact with the liquid metal has a nickel-phosphorus coating or a nickel-boron coating, it can be ensured that it will not oxidize during the welding process, thereby improving the product quality. In the nickel plating process, since a plastic material that is not easy to plate is used, nickel plating can be performed as a whole. As a result, the plastic pump housing 5 is not plated, while the metal joint 4 and the metal electrode 3 are effectively nickel plated.

[0036] (5) Magnetic circuit unit assembly: The magnet 2 is installed into the magnet cavity 52. ​​The magnet 2 can be fixed in the magnet cavity 52 by gluing, snapping, interference fit, etc. This effectively reduces the overall height and ensures that the magnet 2 can be closer to the inner flow channel 51. The magnet 2 is preferably Sm2Co 17 Type magnet. Traditional electromagnetic pumps generally use sintered NdFeB magnets, and high temperature resistant grade (temperature resistant over 180°C) sintered NdFeB magnets are expensive. In addition, even if high temperature resistant grade NdFeB magnets are used, the risk of irreversible demagnetization of the magnets cannot be reduced because the magnet temperature is too close to the temperature of the low temperature welding process. Once the magnet is demagnetized, the driving force of the electromagnetic pump will be reduced or even fail. Magnet 2 uses Sm2Co 17 The magnet has a temperature resistance of up to 300-350℃ and is perfectly compatible with low-temperature welding processes without the risk of high-temperature demagnetization.

[0037] (6) Assembling the magnetic circuit unit: Two magnetic conductive shells 1 are made. The magnetic conductive shells are in a U shape. The material of the magnetic conductive shells 1 can be low carbon steel, galvanized steel or ferritic stainless steel, such as DC01, DX51D+Z, 10Cr17 and other grades, and then stamped and bent. They have good magnetic conductivity and can effectively avoid magnetic leakage. The two magnetic conductive shells 1 are symmetrically mounted on the plastic pump housing 5 from both sides, and the opening of the magnet cavity 52 is closed. The two magnetic conductive shells 1 can be fixed to the semi-finished pump body by gluing, snapping, screwing, etc. to obtain a compact ultra-thin electromagnetic pump product.

[0038] (7) See Figure 7 and Figure 8, connect the two metal joints 4 to the two ends of the metal flow channel 8. The connection method can be laser welding, high-frequency pulse cold welding or other welding methods with a small heat-affected zone. Then, liquid metal is injected into the inner flow channel 51 through the injection hole 53. The liquid metal automatically flows into the metal flow channel 8 until it is full. Then, the injection hole 53 is sealed with a rubber plug 6 or a screw to obtain a compact liquid metal electromagnetic pump loop.

[0039] In other embodiments, step (7) may also be moved before step (5), that is, the metal runner 8 is assembled first, and then the magnet 2 and the magnetic shell 1 are assembled.

[0040] According to the disclosure and teaching of the above description, the technical personnel in the field to which the utility model belongs can also change and modify the above implementation. Therefore, the utility model is not limited to the specific implementation methods disclosed and described above, and some modifications and changes to the utility model should also fall within the scope of protection of the claims of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the utility model.

Claims

1. A compact ultra-thin electromagnetic pump, comprising a magnet, characterized in that: It also includes a pump housing unit and a magnetic shell. The pump housing unit includes a metal electrode, a metal joint and a plastic pump housing that is integrally injection molded with the metal electrode and the metal joint. An inner flow channel is provided in the plastic pump housing. The two metal electrodes are located on both sides of the inner flow channel. The two metal joints are located at both ends of the plastic pump housing and are connected to the two ends of the inner flow channel. The magnet is arranged on the plastic pump housing at the upper and lower positions corresponding to the inner flow channel, and the magnetic shell is sleeved on the plastic pump housing.

2. The compact ultra-thin electromagnetic pump according to claim 1, characterized in that: The inner flow channel is flat.

3. The compact ultra-thin electromagnetic pump according to claim 1, characterized in that: The cross-sectional dimensions of the inner flow channel are consistent with the cross-sectional dimensions of the channel of the metal joint, and the inner flow channel and the channel of the metal joint are connected to each other.

4. The compact ultra-thin electromagnetic pump according to claim 1, characterized in that: The electrode plate portion of the metal electrode is located on the inner side wall of the inner flow channel, and the pad portion of the metal electrode is located on the outer surface of the plastic pump housing.

5. The compact ultra-thin electromagnetic pump according to claim 4, characterized in that: The pad portion of the metal electrode is located on the lower surface of the plastic pump housing.

6. The compact ultra-thin electromagnetic pump according to claim 4, characterized in that: The middle part of the metal electrode is in a straight line to form a straight rod part, and the pad parts are arranged at both ends of the straight rod part. The pad parts are exposed from the outer wall of the plastic pump shell and extend to the bottom surface of the plastic pump shell, and the electrode plate part is located at the center of the straight rod part.

7. The compact ultra-thin electromagnetic pump according to claim 1, characterized in that: The surface of the metal joint is provided with evenly distributed indentations.

8. The compact ultra-thin electromagnetic pump according to claim 7, characterized in that: The depth of the dent is 0.05-0.2 mm.

9. The compact ultra-thin electromagnetic pump according to any one of claims 1 to 8, characterized in that: The magnetic shell is U-shaped as a whole, and magnet cavities are provided on the upper and lower surfaces of the plastic pump shell at positions corresponding to the inner flow channel, and the magnet is arranged in the magnet cavities; two magnetic shells are symmetrically mounted on the plastic pump shell from both sides and close the openings of the magnet cavities.

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