A reverse-drive impurity type magnetic pump

Abstract

This invention relates to the field of magnetic pump technology and discloses a reverse-drive impurity type magnetic pump, including a pump chamber. The pump chamber has three channels outside: an inlet, an outlet, and an impurity removal channel. An impeller is provided in the pump chamber. The impeller is connected to the shaft of an inner magnetic rotor and is driven to rotate by a motor connected to the shaft of an outer magnetic rotor. Liquid flows axially into the pump chamber from the inlet. The inlet has a suction chamber, which is a conical cylinder with a gradually and uniformly shrinking cross-sectional area. An inducer wheel is provided on the side of the impeller facing the inlet. The inducer wheel rotates coaxially with the impeller. The blades of the inducer wheel are installed at a small angle, making the flow channel between the blades long and wide, and the number of blades is 2-4.

Description

Technical Field

[0001] This invention relates to the field of magnetic pump technology, specifically to a reverse-drive impurity type magnetic pump. Background Technology

[0002] In a reverse-drive magnetic pump, the motor is connected to the outer magnetic rotor, and the impeller is connected to the inner magnetic rotor. The outer and inner magnetic rotors are directly separated by an isolation sleeve. The power comes from the motor side outside the pump, passing through the isolation sleeve to drive the impeller inside. This "outside-in" magnetic drive method is the origin of the term "reverse drive," which accurately describes the core characteristics of magnetic coupling. The rotation of the motor drives the outer magnetic rotor assembly connected to the motor shaft to rotate synchronously. A set of permanent magnets (usually high-performance neodymium iron boron or samarium cobalt magnets) are firmly installed on the outer magnetic rotor. These magnets are arranged with alternating N and S poles to form a strong spatial alternating magnetic field. In the pump head, there is an inner magnetic rotor coaxially connected to the impeller, on which permanent magnets with the same polarity arrangement are also installed. The inner and outer magnetic rotors are completely separated by a thin-walled seal called an isolation sleeve. When the outer magnetic rotor rotates under the drive of the motor, the rotating magnetic field it generates passes through the isolation sleeve, and the magnetic lines of force "grab" or "drag" the magnets on the inner magnetic rotor, causing the inner magnetic rotor to rotate synchronously with the outer magnetic rotor. This is similar to two magnets separated by a glass plate; if one moves, the other will move as well. The inner magnetic rotor drives the pump shaft and impeller to rotate together. The impeller does work on the liquid in the pump chamber, giving it kinetic and pressure energy, thereby realizing the transportation of the liquid. Ordinary magnetic centrifugal pumps have poor anti-clogging capabilities because they use closed impellers with narrow flow channels, making them easily clogged by particles or fibers. The core principle of impurity-type anti-clogging magnetic pumps is to use open flow channels or impellers, allowing solid particles and fibers to pass through unimpeded, rather than trying to "restrict" them in narrow impeller flow channels. However, the blades of such open impellers are directly exposed to the water flow entering at the inlet. When the liquid enters the pump chamber, the flow direction changes drastically, and the pressure distribution is uneven. It is more likely that the pressure will drop below the saturated vapor pressure in some areas, causing cavitation. When the bubbles burst, they will cause severe erosion damage to the impeller and pump casing. Summary of the Invention

[0003] (a) Technical problem to be solved: In view of the shortcomings of the existing technology, the present invention provides a reverse-drive impurity type magnetic pump, which has the advantage of anti-cavitation and solves the problem of severe cavitation of open impeller.

[0004] (II) Technical Solution: To achieve the above-mentioned anti-cavitation purpose, the present invention provides the following technical solution: a reverse-drive impurity type magnetic pump, including a pump chamber, the pump chamber having an inlet, an outlet and an impurity removal channel outside the pump chamber, an impeller inside the pump chamber, the impeller being connected to the inner magnetic rotor shaft and driven to rotate by a motor connected to the outer magnetic rotor shaft, the liquid in the inlet flowing axially into the pump chamber, the inlet having a suction chamber, the suction chamber being a conical cylinder with a gradually uniformly shrinking cross-sectional area, an inducer wheel on the side of the impeller facing the inlet, the inducer wheel rotating coaxially with the impeller, the inducer wheel blades adopting a low angle of attack design, the flow channel between the blades forming a stable, gradually accelerating and pressurizing environment rather than violent squeezing, and the number of blades being 2-4.

[0005] The pump chamber and the suction chamber are provided with a transition angle with a uniformly expanded cross-sectional area.

[0006] The ratio of the inducer blade diameter to the impeller inlet diameter is 0.9, and the length-to-diameter ratio of the inducer is 1:5.

[0007] The gap between the inducer and impeller axis and the pump chamber is smaller than the gap between the side and the pump chamber.

[0008] The pump chamber is asymmetrically volute-shaped. Along the direction of rotation, the gap between the impeller side near the outlet and the pump chamber is the conveying zone, and the gap near the impurity removal channel is the settling zone. The settling zone is larger than the conveying zone.

[0009] The inner wall of the suction chamber is uniformly arrayed with protruding guide grilles, which are spiral in shape and rotate in the same direction as the impeller in the pump chamber.

[0010] The section of the impeller blades near the inlet is a raised arc shape, with the raised direction pointing in the direction of impeller rotation, while the section away from the inlet is parallel to the axis.

[0011] The width ratio of the convex arc segment to the parallel segment of the impeller blade is 2:1.

[0012] (III) Beneficial Effects: Compared with the prior art, the present invention provides a reverse-drive impurity type magnetic pump with the following beneficial effects: 1. This reverse-drive impurity type magnetic pump, through the funnel-shaped suction chamber with uniformly contracted cross-section at the inlet, can streamline and smoothly accelerate the axially flowing liquid, forming a pre-compressed flow field with uniform and symmetrical pressure distribution before entering the pump chamber. This not only significantly reduces inlet impact loss and eddy generation, providing an ideal working environment for the impeller, but also balances the load between the blades from the source, avoiding "premature" cavitation induced by local low-pressure areas. Subsequently, the smooth transition angle between the suction chamber and the pump chamber completely eliminates the step-like abrupt change in the flow cross-section, further ensuring the continuity and stability of the liquid flow. The core anti-cavitation design lies in the front-mounted inducer, which has 2-4 blades with large installation angles, long flow channels, and adopts an airfoil cross-section. This configuration allows for very gentle "pre-pressurization" and "pre-rotation" of the liquid. Even in extreme conditions where localized cavitation occurs in the main flow, the inducer can confine the generated bubbles to a controllable area on the back of the blades, forming a stable "hypercavitation" state and preventing bubbles from clogging the flow channel. The liquid, after being pressurized by the inducer, has a pressure significantly higher than its vaporization pressure, acting like a treated "safe fluid" before being fed into the main impeller. This greatly improves the pump's required net positive suction head (NPSH) performance, enabling stable operation even at extremely low suction pressures or when conveying easily vaporized media. It significantly improves operational stability and lifespan; the uniform inflow reduces the periodic impact load on the impeller and bearings, thereby reducing vibration and noise and extending the unit's lifespan. It broadens the pump's operating range; its excellent anti-cavitation capability allows it to handle more demanding conditions, such as conveying high-temperature and volatile media. The perfect combination of magnetic drive and a high-efficiency hydraulic model ensures the core advantage of complete leak-free operation without sacrificing hydraulic efficiency. Instead, it maximizes efficiency by optimizing inlet conditions. Enhanced media adaptability, smooth flow channels, and cavitation resistance make it more resistant to transporting liquids containing trace amounts of gaseous components or more easily vaporized liquids.

[0013] 2. This reverse-drive impurity-type magnetic pump, through its unique asymmetric volute design, intelligently achieves simultaneous "solid-liquid separation" and "clean liquid pressurization" within a single pump chamber. In the impeller rotation direction, the pump chamber is cleverly divided into two functionally distinct zones. The large settling zone, utilizing the sharply increased flow area, drastically reduces the velocity of the liquid carrying solid particles, providing a tranquil "haven" for heavy impurities. These impurities are then completely separated from the main flow under the combined action of their own gravity and strong centrifugal force, and smoothly converge along the pump casing wall into the impurity removal channel, thus achieving active and continuous discharge of impurities. Simultaneously, in the spatially converging transport zone, the pre-purified liquid is efficiently collected, its flow rate is steadily increased, and its kinetic energy is systematically converted into the pressure energy required for the outlet. This synergistic mechanism of "low-speed separation in the settling zone and high-speed lifting in the conveying zone" greatly reduces the risk of impurities eroding and clogging core components such as the main impeller and mechanical seal, significantly improving the pump's service life and operational reliability under harsh conditions. It optimizes energy distribution, concentrating the energy mainly used for conveying clean liquids in the conveying zone, avoiding unnecessary energy consumption in stirring and carrying solid particles, thereby improving the overall pump operating efficiency. This design, together with the front-end inducer and suction chamber, forms a perfect relay. The inducer ensures that the liquid enters the impeller in a stable, cavitation-free state, while the centrifugal force generated by the impeller becomes the original driving force for solid-liquid separation. Finally, the asymmetric volute completes the ultimate task of "separation" and "conveyance".

[0014] 3. This reverse-drive impurity-type magnetic pump features an inlet section of the impeller near the inlet, where the convex arc shape in the direction of rotation acts like a highly efficient "bucket" precisely cutting into the fluid. This allows for a rapid and intense exchange of momentum with the liquid the moment it enters the flow channel, transferring energy to the liquid very early and quickly. This not only significantly improves the pump's head generation capacity but, more importantly, it powerfully enhances the impeller's anti-cavitation performance. The earlier the pressure builds up, the less likely the liquid is to vaporize on the impeller surface. Subsequently, at the rear of the impeller, the flow channel becomes parallel to the axis, providing a low-resistance, low-turbulence stable flow channel for the liquid that has already acquired its main energy. This allows the liquid to flow smoothly towards the pump casing, efficiently converting the previously acquired kinetic energy into stable pressure energy and minimizing internal eddies and impact losses. This synergistic design of "powerful pressurization at the front and stable flow guidance at the rear" firstly forms a perfect "relay race" with the front-mounted inducer. The inducer is responsible for raising the liquid pressure above the safety line, while the forward-inclined blades of the main impeller take over the "baton" and provide the final efficient pressurization, together constructing a double-layered and robust defense against cavitation. This ability to quickly build up pressure further strengthens the driving force for solid-liquid separation within the asymmetric volute, ensuring that the settling zone has sufficient centrifugal force to throw out solid particles. It optimizes the load distribution inside the impeller, avoids local stress concentration that may be caused by a single profile, and improves the mechanical strength and lifespan of the impeller. At the same time, this smooth profile transition also significantly reduces operating noise and vibration, making the overall operation of the pump more stable and quiet. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention;

[0016] Figure 2 This is a cross-sectional view of the front of the pump chamber of the present invention;

[0017] Figure 3 This is a cross-sectional view of the pump chamber of the present invention from the side direction;

[0018] Figure 4 This is a schematic diagram of the inducer and impeller structure of the present invention;

[0019] Figure 5 This is a side view of the inducer and impeller of the present invention.

[0020] In the diagram: 1. Pump chamber; 11. Inducer wheel; 12. Impeller; 13. Suction chamber; 101. Inlet; 102. Outlet; 103. Impurity removal channel; 131. Transition angle; 1001. Settling zone; 1002. Conveying zone. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1-5 A reverse-drive impurity-type magnetic pump includes a pump chamber 1. The pump chamber 1 has three channels: an inlet 101, an outlet 102, and a purification channel 103. An impeller 12 is installed inside the pump chamber 1. The impeller 12 is connected to the shaft of an inner magnetic rotor and is driven to rotate by a motor connected to the shaft of an outer magnetic rotor. Liquid flows axially into the pump chamber 1 through the inlet 101. The inlet 101 has a suction chamber 13, which is a cone-shaped cylinder with a gradually shrinking cross-sectional area. An inducer 11 is installed on the side of the impeller 12 facing the inlet 101. The inducer 11 rotates coaxially with the impeller 12. The blades of the inducer 11 adopt a low angle of attack design, creating a stable, gradually accelerating, and pressurized environment between the blades, rather than intense compression. The low angle of attack ensures that the fluid flows tightly against the blade surface, preventing stripping and eddies due to excessive angle. In the long flow channel, the fluid has sufficient time and space to be gradually driven and accelerated by the rotation of the blades. The number of blades is 2-4, and a transition angle 131 with uniformly expanded cross-sectional area is provided between the pump chamber 1 and the suction chamber 13.

[0023] A suction chamber 13 is located at the inlet flange 101. The cross-sectional area of ​​the suction chamber 13 is a gradually and uniformly contracting conical cylinder, shaped like a trumpet. According to the continuity equation Q=A·V, as the cross-sectional area of ​​the flow channel decreases, the flow velocity will increase uniformly. According to Bernoulli's principle, an increase in velocity will lead to a decrease in pressure. The straight conical design ensures that the liquid across the entire cross-section is accelerated synchronously and smoothly, avoiding sudden high speeds and pressure drops in local areas. This allows the overall pressure level to decrease orderly within a controllable range, rather than suddenly collapsing at a certain point. It guides the axially flowing liquid to the impeller 12 surface in the pump chamber 1 in a streamlined manner, greatly reducing flow separation, impact, and vortex generation. It can provide a flow field with a very symmetrical and uniform velocity and pressure distribution to the impeller inlet. Each blade on the impeller can receive liquid under almost identical conditions, avoiding the situation where some blades are affected by external pressure. Poor flow can lead to premature cavitation. Meanwhile, a transition angle 131 is provided between the suction chamber 13 and the pump chamber 1. The diameter of the front end of the transition angle 131 is the same as the diameter of the end of the suction chamber 13, and the diameter of the end of the transition angle 131 is the same as the diameter of the pump chamber 1. This avoids a step-like abrupt change in the liquid flow cross-sectional area. An inducer 11 is provided on the side of the impeller 12 facing the inlet 101. The inducer 11 is coaxially arranged with the impeller 12, and the blades of the inducer 11 wrap around the hub. The installation angle is very small, making its displacement effect on the liquid weak. The flow channel between the blades is very long and wide. The blade cross-section adopts a special aerospace airfoil design, so that when local cavitation occurs, the bubbles are confined to the back of the blades and do not block the entire flow channel. This state is called "super cavitation." After being pressurized by the inducer 11 and pre-rotated, the liquid pressure is much higher than the vaporization pressure. At this point, this "safe" liquid is sent into the impeller 12.

[0024] The ratio of the blade diameter of the inducer 11 to the inlet diameter of the impeller 12 is 0.9, and the length-to-diameter ratio of the inducer 11 is 1:5. The diameter of the inducer 11 blade is slightly smaller than that of the impeller 12 inlet, forming a small step. This ensures that the pre-pressurized liquid discharged from the inducer 11 can be precisely "delivered" to the optimal angle of attack of the main impeller 12 blades, rather than impacting the impeller 12 hub or front cover plate. This 0.9 ratio is optimized to ensure sufficient flow area while avoiding inlet flow interference and additional losses caused by excessive diameter. Under low inlet pressure, local flow inevitably occurs within the inducer 11. In the case of cavitation, the 1:5 length-to-diameter ratio provides ample space and time for bubble generation, development, and collapse, ensuring that bubbles collapse only within the flow channel and do not extend into the downstream impeller 12. The inducer 11 can operate stably in this state, acting as a "cavitation container." The axial clearance between the inducer 11 and impeller 12 and the pump chamber 1 is smaller than the axial clearance between the inducer 11 and the pump chamber 1. The smaller axial clearance means that the backflow leakage path from the high-pressure area at the outlet of the inducer 11 to the low-pressure area at the inlet is narrower and has greater resistance. This forces more liquid to flow forward along the designed flow channel and into the impeller 12, rather than consuming energy through internal circulation.

[0025] See Figure 3 The pump chamber 1 is an asymmetric volute. Along the direction of rotation, the gap between the impeller 12 and the pump chamber 1 near the outlet 102 forms the conveying zone 1002. This space is converging, and the reduced area leads to a rebound in flow velocity, thus efficiently converting the kinetic energy of the pre-separated, relatively clean liquid into pressure energy for final discharge. The gap near the impurity removal channel 103 forms the settling zone 1001. The settling zone 1001 is larger than the conveying zone 1002, and its spaciousness, according to the fluid continuity equation (Q = A × V), increases in area A inevitably lead to a significant decrease in flow velocity V. This low-speed environment provides conditions for the settling and aggregation of heavy solid particles ejected by centrifugal force, preventing them from being re-entrained by the high-speed liquid flow. In this area, solid particles "crawl" along the pump casing wall and move towards the impurity removal channel.

[0026] The inner wall of the suction chamber 13 is uniformly arrayed with protruding guide grids. The guide grids are spiral in shape and their rotation direction is consistent with the rotation direction of the impeller 12 in the pump chamber 1, so that the water flow is pre-swirled before entering the pump chamber 1, and the water flow direction is more orderly.

[0027] See Figures 4-5The blades of the impeller 12 have a raised arc shape near the inlet 101, with the direction of the raised arc being the direction of rotation of the impeller 12. The forward-leaning raised arc design allows the blades to have a vigorous momentum exchange with the fluid at the inlet, like a powerful little shovel, which can transfer energy to the liquid earlier and more effectively, increasing the head. The section away from the inlet 101 is parallel to the axis. After the main energy of the fluid is added, the parallel flow channel provides a stable, low-turbulence path. The width ratio of the raised arc section to the parallel section of the impeller 12 blades is 2:1.

[0028] Working Principle: In the reverse-drive magnetic pump, the motor is connected to the outer magnetic rotor, and the impeller 12 is connected to the inner magnetic rotor. The outer and inner magnetic rotors are directly separated by an isolation sleeve. Power is supplied from the external motor side of the pump, passing through the isolation sleeve to drive the internal impeller 12. This "outside-to-inside" magnetic drive method is the origin of the term "reverse drive," which accurately describes the core characteristic of magnetic coupling. Ordinary magnetic centrifugal pumps have poor anti-clogging capabilities because they use closed impellers with narrow flow channels, making them easily clogged by particles or fibers. The core principle of the impurity-type anti-clogging magnetic pump is to use an open flow channel or impeller 12, allowing solid particles and fibers to pass through unimpeded, rather than attempting to "restrict" them to the narrow impeller 12 flow channel. Because the impeller 12 rotates within the pump chamber... A low-pressure vortex zone is generated at the center, and the annular space of pump chamber 1 is the main flow channel. The main kinetic energy and flow direction of the liquid are determined by this main vortex. The density of solid particles is usually different from that of liquid. Due to centrifugal force and other factors, they are "thrown" towards the periphery of pump chamber 1, where the energy is more stable and the space is larger, i.e., the path where the main vortex is located. However, the open impeller 12 blades are directly exposed to the water flow entering through inlet 101. When the liquid enters pump chamber 1, the flow direction changes drastically, and the pressure distribution is uneven. It is easier for the pressure to drop below the saturated vapor pressure in local areas, resulting in cavitation. When the bubbles burst, they will cause severe erosion damage to the impeller and pump casing. A suction chamber 13 is provided at the flange of inlet 101. The cross-sectional area of ​​suction chamber 13 gradually and uniformly shrinks. The conical cylinder, shaped like a trumpet, follows the continuity equation Q=A·V. As the cross-sectional area of ​​the flow channel decreases, the flow velocity increases uniformly. According to Bernoulli's principle, increased velocity leads to a decrease in pressure. The straight conical design ensures that the liquid across the entire cross-section is accelerated synchronously and smoothly, avoiding sudden high speeds and pressure drops in localized areas. This allows the overall pressure level to decrease systematically within a controllable range, rather than collapsing abruptly at a point. It guides the axially flowing liquid to the impeller 12 surface in a streamlined manner, greatly reducing flow separation, impact, and vortex generation. It provides a highly symmetrical and uniform flow field with both velocity and pressure distribution to the impeller inlet. Each blade on the impeller receives liquid under almost identical conditions, avoiding... This design prevents some blades from prematurely cavitating due to poor inflow. Furthermore, a transition angle 131 is provided between the suction chamber 13 and the pump chamber 1. The diameter of the front end of the transition angle 131 is the same as the diameter of the end of the suction chamber 13, and the diameter of the end of the transition angle 131 is the same as the diameter of the pump chamber 1. This avoids a sudden, step-like change in the liquid flow cross-sectional area. An inducer 11 is located on the side of the impeller 12 facing the inlet 101. The inducer 11 is coaxially arranged with the impeller 12, and its blades wrap around the hub. The installation angle is very small, resulting in a weaker displacement effect on the liquid. The flow channel between the blades is very long and wide. The blade cross-section adopts a special aerospace airfoil design, which ensures that in the event of localized cavitation, the bubbles are confined to the back of the blades and do not block the entire flow channel. This state is called "super cavitation."After being pressurized by the inducer 11 and pre-rotated, the liquid pressure is now much higher than the vaporization pressure. At this point, this "safe" liquid is then fed into the impeller 12.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A reverse-drive impurity-type magnetic pump, comprising a pump chamber (1), wherein the pump chamber (1) is provided with three channels outside the pump chamber (1): an inlet (101), an outlet (102), and an impurity removal channel (103); an impeller (12) is provided inside the pump chamber (1), the impeller (12) being connected to the shaft of an inner magnetic rotor and driven to rotate by a motor connected to the shaft of an outer magnetic rotor, characterized in that: The liquid in the water inlet (101) flows into the pump chamber (1) axially, the water inlet (101) is provided with a suction chamber (13), the suction chamber (13) is a tapered cylinder with gradually uniform cross-sectional area contraction, the inducer (11) is arranged on the side of the impeller (12) facing the water inlet (101), the inducer (11) rotates coaxially with the impeller (12), the inducer (11) blades adopt low angle of attack design, the flow channel between the blades forms a stable, gradually accelerated and pressurized environment, rather than violent extrusion, and the number of blades is 2-4, the transition angle (131) with uniform cross-sectional area expansion is arranged between the pump chamber (1) and the suction chamber (13), the pump chamber (1) is asymmetric volute, along the rotation direction, the gap between the impeller (12) side near the water outlet (102) and the pump chamber (1) is the conveying area (1002), and the gap near the impurity removal channel (103) is the settling area (1001), the space of the settling area (1001) is greater than that of the conveying area (1002).

2. A reverse drive impeller magnetic pump according to claim 1, characterized in that: The blade of the inducer (11) and the inlet diameter of the impeller (12) are in the proportion of 0.9, and the length-diameter ratio of the inducer (11) is 1:

5.

3. A reverse drive impeller magnetic pump according to claim 2, characterized in that: The gap between the inducer (11) and the inner wall of the pump chamber (1) on the axis direction of the inducer (11) is less than the gap between the outer periphery of the inducer (11) and the inner periphery of the pump chamber (1).

4. A reverse drive impeller magnetic pump according to claim 1, characterized in that: The inner wall of the suction chamber (13) is uniformly arrayed with protruding flow guide grilles.

5. A reverse drive impeller magnetic pump according to claim 4, characterized in that: The flow guide grille is spiral, and the rotation direction is consistent with the rotation direction of the impeller (12) in the pump chamber (1).

6. A reverse drive impeller magnetic pump according to claim 1, characterized in that: The blade of the impeller (12) near the water inlet (101) is in the form of convex arc, and the convex direction is the rotation direction of the impeller (12), and the section far from the water inlet (101) is parallel to the axis.

7. A reverse drive impeller magnetic pump according to claim 6, characterized in that: The width ratio of the convex arc section and the parallel section of the impeller (12) blade is 2:1.

Images