Modular self-cooling electromagnetic direct drive self-suction multi-stage pump

Abstract

The application discloses a modular self-cooling electromagnetic direct-drive self-suction multistage pump, which comprises a main shaft, a disc motor assembly, multistage impellers, guide vanes, a junction box, an inlet volute, an outlet volute and a self-suction cavity; the disc motor assembly is fixed on the main shaft; a plurality of stages of impellers and guide vanes are connected in series on the main shaft on both sides of the disc motor in the axial direction; the first-stage impeller corresponds to the inlet volute and forms a first self-suction cavity; the last-stage impeller corresponds to the outlet volute and forms a second self-suction cavity; a backflow hole is arranged on the volute to realize self-suction; the stages of impellers, the guide vanes and the volutes are connected through stud modules, and the number of stages can be increased or decreased according to the lift demand; an axial cooling flow channel is arranged in the main shaft and the rotor; liquid is transported into the flow channel through end face openings, and flows through the stator-rotor air gap to take away heat, so that an external cooling device is not needed. The electromagnetic direct-drive is adopted, the structure is compact, the volume is small, the heat dissipation efficiency is high, and the disassembly, maintenance and assembly are convenient; and the bearing is lubricated by using the conveying medium, so that there is no pollution and leakage risk.

Description

Technical Field

[0001] This invention belongs to the technical field of self-priming multistage centrifugal pumps, specifically relating to a modular self-cooling electromagnetic direct-drive self-priming multistage pump. Background Technology

[0002] Self-priming multistage centrifugal pumps combine the advantages of self-priming pumps and multistage pumps. They can automatically vent air and prime water during startup, while providing a high head. They are widely used in municipal engineering, industrial systems, agricultural irrigation, and shipbuilding industries.

[0003] However, the existing structure still has the following shortcomings: (1) Large size and low transmission efficiency: Traditional multistage pumps usually use an external motor, which is connected to the pump shaft through a coupling, resulting in a long axial dimension and a large space occupation. In addition, the coupling transmission brings additional energy loss.

[0004] (2) The cooling method has obvious defects: Self-fan cooling: low cooling efficiency (prone to excessive temperature rise in high-temperature environments), sensitive to dust, and high noise (≥85dB).

[0005] Forced air cooling: The additional fan consumes 1% to 3% of the rated power, relies on an external power supply, and is not suitable for explosion-proof environments.

[0006] Water-cooled jacket cooling: There are risks of scaling and leakage. It requires a water pump, water tank and pipeline, making the system complex and costly to maintain.

[0007] Oil cooling: poor fluidity at low temperatures, oil deterioration affecting insulation, and high cost.

[0008] (3) Inconvenient maintenance: The impellers and guide vanes of traditional multistage pumps are usually integrally cast or fixed in series. Once a stage is damaged, disassembly and assembly are cumbersome and replacement of parts takes a long time.

[0009] (4) Complex bearing lubrication: Most bearings use oil lubrication, which poses a risk of oil leakage and contamination, and requires regular oil changes. Summary of the Invention

[0010] To address the technical problems existing in the prior art, this invention provides a modular, self-cooled, electromagnetically driven, self-priming multistage pump, comprising a main shaft, a disc motor, multistage impellers, guide vanes, an inlet volute, an outlet volute, and a self-priming chamber, characterized in that: The disc motor adopts a two-stator-one-rotor structure, including two stator assemblies and one rotor assembly. The rotor assembly is fixed on the main shaft and located between the two stator assemblies. Several stages of impellers and guide vanes are connected in series on both sides of the axial direction of the disc motor on the main shaft. The first stage impeller is matched with the inlet volute, the last stage impeller is matched with the outlet volute, and the intermediate stages of impellers are matched with guide vanes. A first self-priming chamber is formed between the first-stage impeller and the inlet volute, and a second self-priming chamber is formed between the last-stage impeller and the outlet volute; both the inlet volute and the outlet volute are provided with reflux holes, which connect the self-priming chamber and the inner cavity of the volute. The main shaft and the rotor assembly are provided with an axially penetrating cooling channel. The disc motor has circular holes at both ends of its axial direction. The two ends of the cooling channel are respectively connected to the pump chambers on both sides of the motor assembly through the circular holes. The impeller, guide vanes, inlet volute, and outlet volute are connected and fixed to the disc motor via studs, forming a modular structure.

[0011] Furthermore, The stator assembly includes a stator housing, motor windings disposed within the stator housing, and a shielding sleeve wrapped around the outside of the stator housing. The stator housing is filled with sealant. The rotor assembly includes a rotor core, a permanent magnet, and a shielding sleeve wrapped around the outside of the rotor core. The rotor core is filled with sealant. The stator assembly and the rotor assembly are separated only by an axial air gap, through which the cooling liquid flows to remove heat from the motor.

[0012] Furthermore, the main shaft is supported at both ends of the disc motor by sliding bearings, which are respectively installed in bearing seats on both sides of the disc motor along the axial direction; thrust bearings are respectively provided between the two stator assemblies and the rotor assembly of the disc motor; both the sliding bearings and the thrust bearings are lubricated by the liquid medium delivered by the impeller, without the need for external lubricating oil.

[0013] Furthermore, the top of the inlet volute is provided with a water injection hole, which is connected to the self-priming chamber and is used to inject a certain amount of water into the self-priming chamber before the pump is started, so as to form self-priming.

[0014] Furthermore, the impeller is fixed to the main shaft by a key, and the impellers are arranged at intervals along the axial direction of the main shaft; the guide vanes, the inlet volute, and the outlet volute are detachably connected to the disc motor by studs. Each stage of the impeller, the guide vane, and the volute constitutes an independent modular unit, and the number of stages of the impeller and the guide vane can be increased or decreased on the main shaft according to the target head requirement.

[0015] Furthermore, an inlet pressure gauge is installed at the inlet of the inlet volute, and an outlet pressure gauge is installed at the outlet of the outlet volute, for monitoring the pressure difference between the pump inlet and outlet. A flow meter is also installed at the outlet of the outlet volute to monitor the pump's outlet flow rate in real time. Vibration sensors are installed on the outer wall of the inlet and outlet volutes to monitor the vibration amplitude during pump operation. Temperature sensors are provided in each of the two stator assemblies near the shielding sleeve to monitor the temperature of the motor stator.

[0016] Furthermore, the outlet volute or inlet volute has a threaded mounting hole on its shell. The threaded mounting hole is used to install a medium monitoring sensor. The medium monitoring sensor includes one or more of a pH sensor, a temperature sensor, a turbidity sensor, and an online viscometer. The medium monitoring sensor extends into the self-priming cavity through the threaded mounting hole and directly contacts the conveyed medium to monitor the medium characteristics.

[0017] Furthermore, an axial displacement monitoring device is provided at the end of the outlet volute, the axial displacement monitoring device including an eddy current sensor or a displacement sensor; The axial displacement monitoring device extends into the second self-priming cavity through the mounting hole opened on the end face of the outlet volute. The detection end of the axial displacement monitoring device is arranged opposite to the end face of the spindle and maintains a small clearance fit, which is used to monitor the axial movement of the spindle in real time during operation.

[0018] Furthermore, the top of the disc motor is provided with a junction box, and the lead cables of the two stator assemblies converge to the junction box through the wiring channel; the junction box is provided with wiring terminals, and the lead cables are connected to the external power line inside the junction box; the outlet of the junction box is provided with a sealing structure.

[0019] Furthermore, the cooling channel is formed by the axial through hole inside the main shaft and the air gap between the stator and rotor; the circular opening on the end face of the bearing seat is respectively connected to both ends of the cooling channel, so that the liquid is transported from the pump chamber on the axial side of the disc motor into the cooling channel through the circular opening, flows through the air gap between the stator assembly and the rotor assembly, and then flows out from the circular opening at the other end to the pump chamber on the other side of the motor assembly, forming a circulating cooling circuit for the disc motor.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses a disc motor and pump body for direct drive, eliminating the need for a coupling, shortening the axial dimension, significantly reducing the overall size of the machine, and improving transmission efficiency; the disc motor adopts a two-stator-one-rotor structure, with two stator assemblies symmetrically arranged on both sides of the rotor assembly, providing greater driving force, while both stators can effectively dissipate heat through cooling channels. The motor has internal cooling channels, and the medium flows directly through the air gap between the stator and rotor to remove heat. There is no need for an external fan or water cooling jacket, resulting in high heat dissipation efficiency, low noise, and no risk of coolant leakage. Both the stator and rotor are equipped with shielding sleeves and sealed with sealant to ensure that liquid does not seep into the motor and cause insulation damage or rusting of parts. The impeller, guide vane, and volute are all modularly connected by studs, allowing for quick addition or removal of stages to adjust the head. Any damaged part can be replaced individually, making disassembly and assembly time-saving and convenient. Each stage of the impeller is fixed to the main shaft by a key, and the guide vane and volute are detachably connected to the disc motor by studs. The structure is clear and maintenance is convenient. Sliding bearings and thrust bearings that use the conveying medium for lubrication do not require lubricating oil, have no risk of pollution or leakage, have a simple structure, and are suitable for frequent start-stop conditions; they have a small number of bearings, long maintenance cycles, and high operational reliability. The first and second self-priming chambers, together with the return hole, enable the self-priming function. The automatic air venting and water priming during startup make it easy to use. The water injection hole can pre-fill the self-priming chambers with water to ensure a fast and reliable self-priming process. It is especially suitable for applications that require frequent startup or have no backflow conditions. It has a complete monitoring system, including inlet and outlet pressure monitoring, outlet flow monitoring, vibration monitoring, motor temperature monitoring, axial displacement monitoring, and media characteristic monitoring (pH value, temperature, turbidity, viscosity). It can upload the working status and working environment of the pump set in real time to achieve intelligent operation and maintenance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall external structure of the present invention; Figure 2 This is a cross-sectional view of the internal structure of the present invention; Figure 3 This is a magnified view of a disc motor. Figure 4 This is a schematic diagram showing the location of the first self-priming chamber and the reflux hole; Figure 5 This is a schematic diagram showing the location of the second self-priming chamber and the reflux hole; Figure 6 This is a schematic diagram of the cooling channel routing.

[0022] In the diagram: 1. Pump inlet; 2. Stud; 3. Water injection hole; 4. Junction box; 5. Pump outlet; 6. Impeller; 7. Shaft sleeve; 8. First sliding bearing; 9. Stator assembly; 901. Motor winding; 902. Stator housing; 10. Outlet volute; 11. Inlet volute; 12. Guide vane; 13. Rotor assembly; 14. Second sliding bearing; 15. Elastic retaining ring; 16. End face opening; 17. Intermediate flow channel; 18. First self-priming chamber; 19. Second self-priming chamber; 20. First self-priming chamber return hole; 21. Second self-priming chamber return hole; 22. Rotor shielding sleeve; 23. Stator shielding sleeve; 24. Thrust bearing; 25. Main shaft; 26. Left end circular hole; 27. Right end circular hole; 28. Bearing housing. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0025] like Figure 1 and Figure 2 As shown, this invention provides a modular self-cooled electromagnetic direct-drive self-priming multistage pump, including a disc motor. The disc motor adopts a two-stator-one-rotor structure, internally containing two stator assemblies 9 and one rotor assembly 13. The rotor assembly 13 is fixed on the main shaft 25 and located between the two stator assemblies 9, with the two stator assemblies 9 respectively arranged on both axial sides of the rotor assembly 13. The disc motor has an inlet volute 11 on the left side and an outlet volute 10 on the right side, with a junction box 4 on the top. The top of the inlet volute 11 has a water injection hole 3. The disc motor has a horizontally arranged main shaft 25 inside, which is supported at the left and right ends of the disc motor by a first sliding bearing 8 and a second sliding bearing 14, respectively. The first sliding bearing 8 and the second sliding bearing 14 are respectively fixed on bearing seats 28. Thrust bearings 24 are symmetrically arranged between the two stator assemblies 9 and the rotor assembly 13 of the disc motor. Both the sliding bearings and the thrust bearings are lubricated by a liquid medium delivered by the impeller, requiring no external lubricating oil.

[0026] A rotor assembly 13 is mounted in the middle of the main shaft 25. The rotor assembly 13 is a permanent magnet rotor, and stator housings 902 are provided at both ends of it. The motor windings 901 are fixed to the inner wall of the stator housings 902. Figure 3 As shown, the stator assembly 9 includes a stator housing 902, motor windings 901 disposed within the stator housing 902, and a stator shielding sleeve 23 surrounding the stator housing 902. The stator housing 902 is filled with sealant to ensure that liquid cannot enter the windings and can only flow through the axial air gap between the stator and rotor. The rotor assembly 13 includes a rotor core, permanent magnets, and a rotor shielding sleeve 22 surrounding the rotor core. The rotor core is also filled with sealant. Only an axial air gap is left between the stator assembly 9 and the rotor assembly 13 for the transported liquid to pass through, achieving isolation from the transported medium.

[0027] Several stages of impellers 6 and guide vanes 12 are sequentially installed on the main shaft 25, located on the left side of the rotor assembly 13. The leftmost impeller is the first stage, corresponding to the inlet volute 11. Similarly, several stages of impellers 6 and guide vanes 12 are sequentially installed on the right side, with the rightmost impeller being the last stage, corresponding to the outlet volute 10. Each impeller 6 is fixed to the main shaft 25 by a key, and each guide vane 12 and volute (inlet volute 11, outlet volute 10) is fixedly connected to the disc motor assembly by studs 2, forming a modular whole. Each stage of impeller 6, guide vane 12, and volute constitutes an independent modular unit. When it is necessary to increase the head, the number of impellers 6 and guide vanes 12 can be increased on the left and right sides respectively. Only the studs of the corresponding length need to be replaced, without replacing the entire machine.

[0028] like Figure 4 and Figure 5 As shown, the inlet volute 11 and the first-stage impeller form a first self-priming chamber 18, and the outlet volute 10 and the last-stage impeller form a second self-priming chamber 19. The top of the inlet volute 11 has a water injection hole 3, which communicates with the first and second self-priming chambers 18 and 19, used to inject a certain amount of water into the self-priming chamber before pump startup to achieve self-priming. The inlet volute 11 has a first return hole 20, and an end face opening 16 is also provided on its end face, through which the pumping medium flows into the second-stage impeller. The outlet volute 10 has a second return hole 21, which connects the self-priming chamber and the inner cavity of the volute, allowing the liquid in the self-priming chamber to flow back into the volute.

[0029] like Figure 6As shown, the main shaft 25 and rotor assembly 13 have an axially penetrating cooling channel inside, which is formed by the axial through hole inside the main shaft 25 and the axial air gap between the stator and rotor. The disc motor has a left circular hole 26 and a right circular hole 27 at both ends of the axial direction, and the two ends of the cooling channel are connected to the pump chambers on both sides of the disc motor through the left circular hole 26 and the right circular hole 27, respectively. The liquid is introduced into the pump through inlet 1, pressurized by the first-stage impeller, and enters the first self-priming chamber 18 through the outlet of the inlet volute 11. After being filled, it enters the second-stage impeller through the end face opening 16 for further pressurization. The liquid is then transferred step by step by the guide vanes 12 to the left side of the disc motor. It flows into the cooling channel inside the main shaft and rotor assembly through the left circular hole 26. Some of the medium flows through the axial air gap between the stator assembly 9 and the rotor assembly 13 to directly cool the disc motor. Then it flows out through the right circular hole 27 and enters the right impeller stage for further pressurization. Finally, it is discharged into the second self-priming chamber 19 by the last impeller and discharged through the pump outlet 5, forming a circulating cooling circuit for the disc motor.

[0030] The self-priming process is as follows: Before starting the pump, a certain amount of water is injected into the pump through the water injection hole 3. The water enters the first self-priming chamber 18 and the second self-priming chamber 19. After starting, the first-stage impeller rotates at high speed, throwing out the water-gas mixture in the self-priming chamber. The liquid flows back into the volute through the return hole 20, and the gas is discharged from the pump outlet 5, creating a negative pressure at the impeller inlet. This continuously discharges air from the inlet pipe and draws in liquid, completing the self-priming process. The second self-priming chamber 19 serves the same purpose, ensuring that gas can also be discharged from the outlet side.

[0031] Regarding the monitoring system, a temperature sensor (not shown in the figure) is installed inside the stator housing 902 near the stator shield 23. The signal line is led out through the junction box 4 to monitor the motor temperature in real time. An inlet pressure gauge is installed at the pump inlet 1, and an outlet pressure gauge is installed at the pump outlet 5 to monitor the pressure difference between the pump inlet and outlet. A flow meter is installed at the pump outlet 5 to monitor the pump outlet flow rate in real time. Vibration sensors are installed on the outer walls of the inlet volute 11 and the outlet volute 10 to monitor the vibration amplitude during pump operation. Threaded mounting holes are made on the outer housing of the first self-priming chamber 18 or the second self-priming chamber 19 to install a pH sensor, a temperature sensor, a turbidity sensor, and an online viscometer, respectively. Each sensor extends into the self-priming chamber through the threaded mounting holes and directly contacts the conveyed medium to monitor the medium characteristics (pH value, temperature, turbidity, viscosity). An axial displacement monitoring device (such as an eddy current sensor or a displacement sensor) is installed at the tail end (right end) of the main shaft 25. A mounting hole is made on the end face of the outlet volute 10 to insert the sensor and monitor the axial movement of the shaft. The junction box 4 on the top of the disc motor is equipped with wiring terminals. The lead cables of the two stator assemblies 9 are gathered in the junction box 4 through the wiring channel and connected to the external power line in the junction box 4. The outlet of the junction box 4 is equipped with a sealing structure to prevent liquid from seeping in.

[0032] In summary, these are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the specification are within the scope of the present invention.

Claims

1. A modular, self-cooled, electromagnetically driven, self-priming multistage pump, comprising a main shaft, a disc motor, multistage impellers, guide vanes, an inlet volute, an outlet volute, and a self-priming chamber, characterized in that: The disc motor adopts a two-stator-one-rotor structure, including two stator assemblies and one rotor assembly. The rotor assembly is fixed on the main shaft and located between the two stator assemblies. Several stages of impellers and guide vanes are connected in series on both sides of the axial direction of the disc motor on the main shaft. The first stage impeller is matched with the inlet volute, the last stage impeller is matched with the outlet volute, and the intermediate stages of impellers are matched with guide vanes. A first self-priming chamber is formed between the first-stage impeller and the inlet volute, and a second self-priming chamber is formed between the last-stage impeller and the outlet volute; both the inlet volute and the outlet volute are provided with reflux holes, which connect the self-priming chamber and the inner cavity of the volute. The main shaft and the rotor assembly are provided with an axially penetrating cooling channel. The disc motor has circular holes at both ends of its axial direction. The two ends of the cooling channel are respectively connected to the pump chambers on both sides of the motor assembly through the circular holes. The impeller, guide vanes, inlet volute, and outlet volute are connected and fixed to the disc motor via studs, forming a modular structure.

2. The self-priming multistage pump according to claim 1, characterized in that: The stator assembly includes a stator housing, motor windings disposed within the stator housing, and a shielding sleeve wrapped around the outside of the stator housing. The stator housing is filled with sealant. The rotor assembly includes a rotor core, a permanent magnet, and a shielding sleeve wrapped around the outside of the rotor core. The rotor core is filled with sealant. The stator assembly and the rotor assembly are separated only by an axial air gap, through which the cooling liquid flows to remove heat from the motor.

3. The self-priming multistage pump according to claim 1, characterized in that: The main shaft is supported at both ends of the disc motor by sliding bearings, which are respectively installed in bearing seats on both sides of the disc motor axially; thrust bearings are respectively provided between the two stator assemblies and the rotor assembly of the disc motor; both the sliding bearings and the thrust bearings are lubricated by the liquid medium delivered by the impeller, without the need for external lubricating oil.

4. The self-priming multistage pump according to claim 1, characterized in that: The top of the inlet volute is provided with a water injection hole, which is connected to the self-priming chamber and is used to inject a certain amount of water into the self-priming chamber before the pump is started, so as to form self-priming.

5. The self-priming multistage pump according to claim 1, characterized in that: The impeller is fixed to the main shaft by a key, and the impellers are arranged at intervals along the axial direction of the main shaft. The guide vanes, the inlet volute, and the outlet volute are detachably connected to the disc motor by studs. Each stage of the impeller, the guide vane, and the volute constitutes an independent modular unit. The number of stages of the impeller and guide vanes can be increased or decreased on the main shaft according to the target head requirement.

6. The self-priming multistage pump according to claim 1, characterized in that: An inlet pressure gauge is installed at the inlet of the inlet volute, and an outlet pressure gauge is installed at the outlet of the outlet volute, for monitoring the pressure difference between the pump inlet and outlet. A flow meter is also installed at the outlet of the outlet volute to monitor the pump's outlet flow rate in real time. Vibration sensors are installed on the outer wall of the inlet and outlet volutes to monitor the vibration amplitude during pump operation. Temperature sensors are provided in each of the two stator assemblies near the shielding sleeve to monitor the temperature of the motor stator.

7. The self-priming multistage pump according to claim 1, characterized in that: The outlet or inlet volute has a threaded mounting hole for mounting a medium monitoring sensor. The medium monitoring sensor includes one or more of a pH sensor, a temperature sensor, a turbidity sensor, and an online viscometer. The medium monitoring sensor extends into the self-priming cavity through the threaded mounting hole and directly contacts the conveyed medium to monitor its characteristics.

8. The self-priming multistage pump according to claim 1, characterized in that: The end of the outlet volute is provided with an axial displacement monitoring device, which includes an eddy current sensor or a displacement sensor. The axial displacement monitoring device extends into the second self-priming cavity through the mounting hole opened on the end face of the outlet volute. The detection end of the axial displacement monitoring device is arranged opposite to the end face of the spindle and maintains a small clearance fit, which is used to monitor the axial movement of the spindle in real time during operation.

9. The self-priming multistage pump according to claim 1, characterized in that: The top of the disc motor is equipped with a junction box, and the lead cables of the two stator assemblies converge to the junction box through the wiring channel; the junction box is equipped with wiring terminals, and the lead cables are connected to the external power supply line inside the junction box; the outlet of the junction box is equipped with a sealing structure.

10. The self-priming multistage pump according to claim 1, characterized in that: The cooling channel is formed by the axial through hole inside the main shaft and the air gap between the stator and rotor. The circular opening on the end face of the bearing seat is respectively connected to both ends of the cooling channel, so that the liquid is pumped from the pump chamber on the axial side of the disc motor into the cooling channel through the circular opening, flows through the air gap between the stator assembly and the rotor assembly, and flows out from the circular opening at the other end to the pump chamber on the other side of the motor assembly, forming a circulating cooling circuit for the disc motor.

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