Intelligent cleaning reverse-flushing multi-stage centrifugal pump

Abstract

The application relates to the field of centrifugal pumps, and discloses a multi-stage centrifugal pump with intelligent cleaning and reverse flushing, which comprises a multi-stage centrifugal pump body, a water inlet arranged on one side surface of the multi-stage centrifugal pump body and a water outlet arranged on the top of one end of the multi-stage centrifugal pump body; a hollow switching shell is arranged on the side surface of the water inlet in a communication mode, the inner cavity of the switching shell is in a cylindrical shape, a filter switching assembly is arranged on the inner side of the switching shell, the filter switching assembly comprises a switching shaft rotatably arranged on the middle part of the inner side of the switching shell, and a pair of oppositely arranged filter plates are arranged on the side wall of the switching shaft. The multi-stage centrifugal pump with intelligent cleaning and reverse flushing can realize filter blocking and blockage monitoring and automatic cleaning through the cooperation of the switching shell, the filter switching assembly, the first sealing plate, the water pressure sensor and the pipeline assembly, and the efficiency is improved without shutdown.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of centrifugal pumps, in particular to a multi-stage centrifugal pump with intelligent cleaning and reverse flushing. BACKGROUND

[0002] A multi-stage centrifugal pump is a high-efficiency fluid conveying device that realizes step-by-step liquid pressure increase by connecting multiple impellers in series. Its core advantage lies in significantly increasing the limited lift of a single-stage impeller through multi-stage superposition, and it is widely used in deep well water lifting, high-pressure boiler water supply, long-distance pipeline transportation, and other high-lift demand scenarios. To prevent impurities from entering the pump cavity and causing impeller wear or flow passage blockage, existing technologies usually provide a filter structure, such as a filter screen, filter basket, or cyclone separator, at the water inlet of the pump to filter out solid particles, fibers, and other foreign matter through physical interception, thereby protecting the normal operation of the precision components inside the pump.

[0003] However, the filter structure of existing multi-stage centrifugal pumps has certain defects: when the filter assembly gradually clogs due to long-term interception of impurities, the system pressure loss increases and the flow decreases, requiring the pump to be shut down for disassembly and cleaning or replacement of the filter element. This process not only relies on manual operation and takes a long time, but also causes production process interruption and increased maintenance costs. In addition, frequent disassembly and assembly can easily cause installation errors, further increasing the risk of leakage.

[0004] The traditional filter structure lacks real-time clogging monitoring and automatic cleaning functions, and cannot provide early warning or online processing when clogging occurs, which seriously restricts the continuous operation efficiency and intelligent level of the pump system.

[0005] Therefore, it is necessary to provide a multi-stage centrifugal pump with intelligent cleaning and reverse flushing to solve the above problems. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the defects of the prior art. The present application provides a multi-stage centrifugal pump with intelligent cleaning and reverse flushing, which solves the problems of inconvenient cleaning and inability to monitor clogging in real time.

[0007] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0008] A multi-stage centrifugal pump with intelligent cleaning and reverse flushing, comprising a multi-stage centrifugal pump body, a water inlet provided on one side surface of the multi-stage centrifugal pump body, and a water outlet provided on the top of one end of the multi-stage centrifugal pump body.

[0009] A switching shell is connected to the side surface of the water inlet, and the inner cavity of the switching shell is cylindrical. A filter switching assembly is provided on the inner side of the switching shell. The filter switching assembly comprises a switching shaft rotatably provided in the middle of the inner side of the switching shell. A pair of oppositely arranged filter plates are provided on the side wall of the switching shaft. A driving source is provided at the bottom of the switching shell to drive the rotation of the switching shaft.

[0010] The side wall of the switching shaft is provided with a pair of oppositely arranged first sealing plates, and the filter plates are cross-shaped with the first sealing plates, and the first sealing plates correspond to the edges of the water inlet when one of the filter plates corresponds to the water inlet;

[0011] The water inlet is provided with a water pressure sensor near one end of the multi-stage centrifugal pump body;

[0012] The switching shell is provided with a pipeline assembly, the pipeline assembly includes a first branch pipe arranged on one side of the water outlet, one end of the first branch pipe away from the water outlet corresponds to and communicates with one end of the switching shell near the water pressure sensor, one end of the first branch pipe is provided with a control valve, one side of the first branch pipe is provided with a second branch pipe in communication, one end of the second branch pipe away from the first branch pipe corresponds to and communicates with one side of the switching shell away from the multi-stage centrifugal pump body, and the communication part is opposite to the filter plate arranged away from the water inlet, and one side of the switching shell is provided with a blowdown pipe opposite to the second branch pipe.

[0013] Preferably, the second branch pipe is rotatably arranged with a rotating shaft on the inner side of one end of the switching shell, the rotating shaft is fixed with a sealing ball for plugging the second branch pipe, and a through hole is formed in one side of the sealing ball.

[0014] Preferably, the driving source is used to drive the switching shaft and the rotating shaft to rotate alternately, the driving source includes a transmission box arranged at the bottom of the switching shell, the lower end of the rotating shaft extends to the inner side of the transmission box and is provided with a first gear, the lower end of the switching shaft extends to the inner side of the transmission box and is provided with a second gear, and the inner side of the transmission box is rotatably provided with an incomplete gear between the first gear and the second gear and used for alternating engagement with the first gear and the second gear, the bottom of the transmission box is provided with a motor for driving the incomplete gear to rotate, and when the incomplete gear completes one engagement with the second gear and the first gear, the first gear and the second gear can rotate one hundred and eighty degrees.

[0015] Preferably, the first sealing plate is symmetrically provided with a plugging piece for plugging the bottom of the first branch pipe on both sides of the upper end of the first sealing plate, and the plugging piece is separated from the first branch pipe when the first sealing plate is in the plugging state of the water inlet.

[0016] Preferably, the inner side of the switching shell is provided with a locking assembly, the locking assembly includes a first locking disc arranged at the bottom of the first gear, the bottom of the second gear is provided with a second locking disc, one side of the second locking disc and the first locking disc is provided with an arc-shaped locking groove, and the bottom of the incomplete gear is provided with a fan-shaped locking arc, and the locking arc is used for plug-in cooperation with the locking groove.

[0017] Preferably, the switching shaft is a hollow structure, a middle portion of the inside of the switching shaft is rotationally provided with an inner shaft, a torsion spring is arranged between the end of the inner shaft and the inner wall of the switching shaft, and the filter plate is provided with a connecting plate extending to the inside of the switching shaft and fixedly connected with the side wall of the inner shaft at one end close to the switching shaft.

[0018] Preferably, the side wall of the switching shaft is provided with an opening, the filter plate is provided with a second sealing plate close to one end of the switching shaft, the second sealing plate is arc-shaped and in sliding cooperation with the outer wall of the switching shaft, the second sealing plate is used for plugging the opening, the connecting plate is fixed to the side wall of the second sealing plate, and one end of the connecting plate extends to the inside of the switching shaft through the opening.

[0019] Preferably, the edge of the first sealing plate is provided with a sealing rubber ring.

[0020] Preferably, the inside of the first sealing plate is provided with a piston cavity, the peripheral inside of the first sealing plate is provided with an expansion cavity in communication with the sealing rubber ring and the piston cavity, the expansion cavity and the inside of the piston cavity are filled with a fluid, one end of the inside of the piston cavity away from the expansion cavity is movably connected with a piston rod, one end of the piston rod extends to the inside of the switching shaft and corresponds to the side wall of the inner shaft, the side wall of the inner shaft is provided with an arc-shaped pressing block, one end of the sealing rubber ring is in sliding cooperation with the pressing block, and one end of the pressing block is provided with a slope with elasticity.

[0021] Preferably, the fluid is hydraulic oil.

[0022] Compared with the prior art, the intelligent cleaning reverse flushing multi-stage centrifugal pump has the following beneficial effects:

[0023] 1. The intelligent cleaning reverse flushing multi-stage centrifugal pump, through the cooperation of the switching shell, the filter switching assembly, the first sealing plate, the water pressure sensor and the pipeline assembly, can realize filter blocking and automatic cleaning while monitoring the blockage, and can realize reverse flushing self-cleaning of the filter plate by using a small amount of liquid discharged from the water outlet as a reverse flushing water source, without stopping the machine, thereby improving the efficiency.

[0024] 2. The intelligent cleaning reverse flushing multi-stage centrifugal pump, through the cooperation of the inner shaft, the torsion spring and the connecting plate, can buffer and protect the filter plate, so as to avoid damage to the filter plate caused by instantaneous pressure or excessive pressure; through the cooperation of the pressing block, the slope, the piston rod, the piston cavity, the expansion cavity and the fluid, the expansion of the sealing rubber ring can be realized by driving the rotation of the inner shaft by the filter plate under pressure, so that the larger the water pressure is, the higher the sealing performance between the first sealing plate and the inner wall of the switching shell is, and the possibility of leakage is avoided, thereby realizing compact structure and increasing practicability. BRIEF DESCRIPTION OF DRAWINGS

[0025] The disclosure of the present application will be illustrated with reference to the accompanying drawings. It should be appreciated that the drawings are for illustration purposes only and are not intended to limit the scope of protection of the present application. In the drawings, the same reference numerals are used to refer to the same components. Among them:

[0026] Figure 1 The structural schematic diagram of the present application is shown schematically;

[0027] Figure 2 The structural schematic diagram of the present application is shown schematically;

[0028] Figure 3 The overall structural schematic diagram of the present application is shown schematically;

[0029] Figure 4 The structural schematic diagram of the present application is shown schematically;

[0030] Figure 5 The structural schematic diagram of the present application is shown schematically; Figure 4 from another perspective;

[0031] Figure 6 The structural schematic diagram of the present application is shown schematically;

[0032] Figure 7 The overall structural schematic diagram of the present application is shown schematically;

[0033] Figure 8 The structural schematic diagram of the present application is shown schematically; Figure 7 from another perspective;

[0034] Figure 9 The structural schematic diagram of the present application is shown schematically;

[0035] Figure 10 The structural schematic diagram of the present application is shown schematically;

[0036] Figure 11 The structural schematic diagram of the present application is shown schematically;

[0037] Figure 12 The structural schematic diagram of the present application is shown schematically.

[0038] The figure label: 1, multistage centrifugal pump main body; 2, water outlet; 3, water inlet; 4, switching shell; 5, first branch pipe; 6, second branch pipe; 7, blow-off pipe; 8, transmission box; 9, control valve; 10, rotating shaft; 11, water pressure sensor; 12, switching shaft; 13, filter plate; 14, first sealing plate; 15, blocking piece; 16, sealing rubber ring; 17, opening; 18, inner shaft; 19, torsional spring; 20, pressure block; 21, second sealing plate; 22, connecting plate; 23, piston rod; 24, slope surface; 25, piston cavity; 26, expansion cavity; 27, sealing ball; 28, first gear; 29, second gear; 30, incomplete gear; 31, first locking disc; 32, locking arc; 33, second locking disc; 34, locking groove; 35, through hole; 36, motor. DETAILED DESCRIPTION

[0039] It is easy to understand that according to the technical scheme of the present application, a person skilled in the art can propose a plurality of structure modes and implementation modes which can be replaced with each other without changing the essential spirit of the present application. Therefore, the following detailed description and the accompanying drawings are only exemplary description of the technical scheme of the present application, and should not be regarded as the whole or regarded as the limitation or restriction of the technical scheme of the present application.

[0040] According to an embodiment of the present application Figures 1-12 is shown.

[0041] As Figures 1-7 , Figure 11As shown, an intelligent cleaning reverse flushing multistage centrifugal pump, including multistage centrifugal pump body 1, set in multistage centrifugal pump body 1 one end side water inlet 3 and set in multistage centrifugal pump body 1 one end top water outlet 2, the side of water inlet 3 is communicated with the hollow switch shell 4, and the inner cavity of switch shell 4 is cylindrical, the inner side of switch shell 4 is rotatably provided with switch shaft 12, the side wall of switch shaft 12 is provided with a pair of oppositely arranged filter plates 13, the bottom of switch shell 4 is provided with a driving source for driving switch shaft 12 to rotate, in order to realize the segmentation of switch shell 4 inner cavity, a pair of oppositely arranged first sealing plate 14 is arranged on the side wall of switch shaft 12, and the filter plate 13 and the first sealing plate 14 are cross-shaped, the edge of the first sealing plate 14 is provided with a sealing rubber ring 16, and the sealing rubber ring 16 is attached to the inner wall of the switch shell 4, when one of the filter plates 13 corresponds to the water inlet 3, the first sealing plate 14 corresponds to the edge of the water inlet 3, the water inlet 3 is provided with a water pressure sensor 11 near one end of the multistage centrifugal pump body 1, the water pressure sensor 11 is located on the side of the switch shell 4 close to the multistage centrifugal pump body 1, the probe of the water pressure sensor 11 extends into the inner cavity of the water inlet 3, the water outlet 2 is provided with a first branch pipe 5 on one side, the first branch pipe 5 is communicated with the end of the switch shell 4 close to the water pressure sensor 11, the first branch pipe 5 is provided with a control valve 9 at one end, the first branch pipe 5 is provided with a second branch pipe 6 on one side, the second branch pipe 6 is communicated with the side of the switch shell 4 away from the multistage centrifugal pump body 1, and the communication part is opposite to the filter plate 13 arranged away from the water inlet 3, the switch shell 4 is provided with a blow-off pipe 7 opposite to the second branch pipe 6 on one side, the blow-off pipe 7 is also provided with a valve, in order to seal the second branch pipe 6, a rotating shaft 10 is rotatably arranged on the inner side of the second branch pipe 6 close to the switch shell 4, the rotating shaft 10 is fixed with a sealing ball 27 for sealing the second branch pipe 6, a through hole 35 is formed in one side of the sealing ball 27, a blocking piece 15 for blocking the bottom of the first branch pipe 5 is arranged on both sides of the upper end of the first sealing plate 14, and when the first sealing plate 14 blocks the water inlet 3, the blocking piece 15 is separated from the first branch pipe 5;

[0042] Further, as Figure 12As shown, the drive source is used to drive the switching shaft 12 and the rotating shaft 10 to rotate alternately. In a preferred embodiment, the drive source includes a transmission box 8 disposed at the bottom of the switching housing 4. The lower end of the rotating shaft 10 extends to the inner side of the transmission box 8 and is provided with a first gear 28. The lower end of the switching shaft 12 extends to the inner side of the transmission box 8 and is provided with a second gear 29. An incomplete gear 30 is rotatably disposed on the inner side of the transmission box 8 between the first gear 28 and the second gear 29 and is used to alternately mesh with the first gear 28 and the second gear 29. A motor 36 is disposed at the bottom of the transmission box 8 to drive the incomplete gear 30 to rotate. When the incomplete gear 30 completes one mesh with the second gear 29 and the first gear 28, both the first gear 28 and the second gear 29 can rotate 180 degrees.

[0043] like Figure 5 , Figure 12 As shown, in order to lock the control valve 9 and the switching shaft 12 when they are not engaged, a first locking disc 31 is provided at the bottom of the first gear 28, and a second locking disc 33 is provided at the bottom of the second gear 29. Both the second locking disc 33 and the first locking disc 31 have an arc-shaped locking groove 34 on one side. The bottom of the incomplete gear 30 has a fan-shaped locking arc 32, which is used to engage with the locking groove 34. The configuration is such that when the incomplete gear 30 is separated from the second gear 29, the locking arc 32 enters the locking groove 34 on the second locking disc 33, and when the incomplete gear 30 is separated from the first gear 28, the locking arc 32 enters the locking groove 34 on the first locking disc 31.

[0044] like Figures 8-9 As shown, in order to provide buffer protection for the filter plate 13, the switching shaft 12 is configured as a hollow structure. An inner shaft 18 is rotatably provided in the middle of the inner side of the switching shaft 12. A torsion spring 19 is provided between the end of the inner shaft 18 and the inner wall of the switching shaft 12. A connecting plate 22 is provided at one end of the filter plate 13 near the switching shaft 12, extending to the inner side of the switching shaft 12 and fixedly connected to the side wall of the inner shaft 18. Specifically, the side wall of the switching shaft 12 is provided with an opening 17. An arc-shaped second sealing plate 21 is provided at one end of the filter plate 13 near the switching shaft 12, which slides with the outer wall of the switching shaft 12. The second sealing plate 21 is used to seal the opening 17. The connecting plate 22 is fixed to the side wall of the second sealing plate 21, and one end of the connecting plate 22 extends into the switching shaft 12 through the opening 17.

[0045] Furthermore, such as Figures 9-10As shown, in order to increase the sealing between the first sealing plate 14 and the inner wall of the switching shell 4, a piston cavity 25 is arranged on the inner side of the first sealing plate 14, and an expansion cavity 26 is arranged on the inner side of the periphery of the first sealing plate 14 and communicates with the sealing rubber ring 16 and the piston cavity 25. The inner side of the expansion cavity 26 and the piston cavity 25 is filled with fluid, which is preferably hydraulic oil, or other liquids with small temperature influence can also be replaced. The inner side of the piston cavity 25 away from the expansion cavity 26 is movably connected with a piston rod 23, one end of the piston rod 23 extends to the inner side of the switching shaft 12 and corresponds to the side wall of the inner shaft 18. The side wall of the inner shaft 18 is provided with an arc-shaped pressing block 20, one end of the sealing rubber ring 16 is in sliding fit with the pressing block 20, and one end of the pressing block 20 is provided with a slope surface 24 which is smoothly transitioned with the outer wall of the pressing block 20.

[0046] In use, the multi-stage impeller in the multi-stage centrifugal pump body 1 rotates, and the liquid enters through the water inlet 3 and is discharged from the water outlet 2 under the centrifugal force of the impeller. During this period, one of the filter plates 13 corresponds to the water inlet 3 to filter impurities, and the other filter plate 13 is at the other end of the switching shell 4 for switching. The first sealing plate 14 is located at the side of the water inlet 3 to achieve sealing, and the water pressure sensor 11 monitors the water pressure during this period to determine the clogging of the filter plate 13. Moreover, when the liquid flows through the water inlet 3 and the switching shell 4, the water pressure pushes the filter plate 13, and the filter plate 13 drives the inner shaft 18 to rotate through the connecting plate 22, and the torsional spring 19 is twisted and generates a reverse force to buffer and protect the filter plate 13. One end of the piston rod 23 always abuts against the side wall of the pressing block 20. When the water pressure is too large, the filter plate 13 drives the inner shaft 18 to rotate more, and at this time the slope surface 24 corresponds to the piston rod 23, and then the slope surface 24 presses the piston rod 23, and the piston rod 23 extrudes the hydraulic oil in the direction of the expansion cavity 26. The hydraulic oil outwardly presses the sealing rubber ring 16, so that the sealing rubber ring 16 has a tendency to expand, and then the larger the water pressure, the tighter the sealing rubber ring 16 is attached to the inner wall of the switching shell 4, avoiding the possibility of leakage;

[0047] When the filter plate 13 is blocked to a certain extent to affect the water output of the water outlet 2, the water pressure value monitored by the water pressure sensor 11 exceeds the preset value, at which point the motor 36 and the control valve 9 are started, and the liquid in the water outlet 2 enters the first branch pipe 5, the sealing ball 27 is in a sealing state against the second branch pipe 6, the sealing piece 15 is in a sealing state against the first branch pipe 5, the two ends of the locking arc 32 correspond to the two locking grooves 34, the control valve 9 and the switching shaft 12 are in a locked state, at which point the rotating shaft 10 and the switching shaft 12 cannot rotate, due to the start of the motor 36, the motor 36 drives the incomplete gear 30 to rotate, one end of the locking arc 32 is separated from the locking groove 34 on the second locking disc 33, the switching shaft 12 is unlocked, then the incomplete gear 30 meshes with the second gear 29, the second gear 29 drives the switching shaft 12 to gradually rotate one hundred and eighty degrees, and then the switching shaft 12 drives the filter plate 13 and the first sealing plate 14 to rotate, the switching shaft 12 rotates counterclockwise, avoiding the impurities upstream of the filter plate 13 from being washed into the multi-stage centrifugal pump body 1, when rotating to the first sealing plate 14 about to cause sealing of the water inlet 3, the sealing piece 15 on one of the first sealing plates 14 is separated from the lower end of the first branch pipe 5, at which point the liquid in the first branch pipe 5 enters the water inlet 3, and then enters the multi-stage centrifugal pump body 1, temporarily achieving self-circulation, avoiding dry running and cavitation of the impeller in the multi-stage centrifugal pump body 1 when the first sealing plate 14 seals the water inlet 3, reducing mechanical damage, when about to rotate one hundred and eighty degrees, the water inlet 3 is gradually opened by the first sealing plate 14 to restore the suction work, the sealing piece 15 on the other first sealing plate 14 will be displaced to the lower end of the first branch pipe 5 for sealing, and normal suction work is performed, at which point, when the switching shaft 12 rotates one hundred and eighty degrees, the incomplete gear 30 is separated from the second gear 29, the locking arc 32 enters the locking groove 34 on the second locking disc 33, then one end of the locking arc 32 is separated from the locking groove 34 on the first locking disc 31, the incomplete gear 30 begins to mesh with the first gear 28, and then the first gear 28 drives the sealing ball 27 to rotate ninety degrees through the control valve 9, at which point the motor 36 stops for a period of time, due to the sealing of the bottom of the first branch pipe 5, the liquid entering the first branch pipe 5 will enter the second branch pipe 6, and then enter the switching shell 4 through the through hole 35 to backwash the filter plate 13, the waste water is discharged through the blow-off pipe 7 for collection and treatment, the other end of the water inlet 3 and the inside of the switching shell 4 normally flows liquid during backwashing, after a period of backwashing, the motor 36 is operated again, the incomplete gear 30 continues to drive the first gear 28 to rotate, so that the sealing ball 27 continues to rotate ninety degrees, so that the through hole 35 is misaligned with the second branch pipe 6, the sealing ball 27 seals the second branch pipe 6 again, the control valve 9 and the motor 36 are closed, and in order to avoid liquid leakage, a valve can also be provided on the blow-off pipe 7;

[0048] It should be noted that due to the existence of the sealing rubber ring 16, the bottom of the first branch pipe 5 cannot be completely sealed by the sealing sheet 15. Even if the sealing sheet 15 leaks when it is located at the bottom of the first branch pipe 5, the leaked liquid will enter the multi-stage centrifugal pump body 1 together with the liquid entering from the water inlet 3, and will not affect the use. The sealing sheet 15 is mainly to ensure that most of the liquid in the first branch pipe 5 can enter the second branch pipe 6 during the backwashing stage, so as to ensure sufficient water pressure for backwashing.

[0049] The technical scope of the present application is not limited to the above description, and those skilled in the art can make various modifications and changes to the above embodiments without departing from the technical idea of the present application, and these modifications and changes shall be within the protection scope of the present application.

Claims

1. A smart cleaning reverse flush multi-stage centrifugal pump characterized by: The utility model provides a multi-stage centrifugal pump body, water inlet arranged on one end side of multi-stage centrifugal pump body and water outlet arranged on one end top of multi-stage centrifugal pump body, The side surface of the water inlet is communicated with a switching shell, and the inner cavity of the switching shell is cylindrical, the inner side of the switching shell is provided with a filter switching assembly, the filter switching assembly comprises a switching shaft rotatably arranged in the middle part of the inner side of the switching shell, the side wall of the switching shaft is provided with a pair of oppositely arranged filter plates, and the bottom of the switching shell is provided with a driving source for driving the rotation of the switching shaft, The side wall of the switching shaft is provided with a pair of oppositely arranged first sealing plates, and the filter plate and the first sealing plate are in a cross shape, when one of the filter plates corresponds to the water inlet, the first sealing plate corresponds to the edge of the water inlet, The water inlet is provided with a water pressure sensor close to one end of the multi-stage centrifugal pump body, The switching shell is provided with a pipeline assembly, the pipeline assembly comprises a first branch pipe arranged on one side of the water outlet, one end of the first branch pipe away from the water outlet corresponds to and is communicated with one end of the switching shell close to the water pressure sensor, one end of the first branch pipe is provided with a control valve, one side of the first branch pipe is communicated with a second branch pipe, one end of the second branch pipe away from the first branch pipe corresponds to and is communicated with one side of the switching shell away from the multi-stage centrifugal pump body, and the communication part is opposite to the filter plate arranged away from the water inlet, one side of the switching shell is provided with a blow-off pipe oppositely arranged with the second branch pipe, The switching shaft is a hollow structure, an inner shaft is rotatably arranged in the middle part of the inner side of the switching shaft, a torsional spring is arranged between the end of the inner shaft and the inner wall of the switching shaft, and one end of the filter plate close to the switching shaft is provided with a connecting plate extending to the inner side of the switching shaft and fixedly connected with the side wall of the inner shaft, The edge of the first sealing plate is provided with a sealing rubber ring, the inner side of the first sealing plate is provided with a piston cavity, the peripheral inner side of the first sealing plate is provided with an inflation cavity communicated with the sealing rubber ring and the piston cavity, the inflation cavity and the piston cavity are filled with a fluid, one end of the piston rod away from the inflation cavity in the inner side of the piston cavity is movably connected, one end of the piston rod extends to the inner side of the switching shaft and corresponds to the side wall of the inner shaft, the side wall of the inner shaft is provided with an arc-shaped pressure applying block, one end of the sealing rubber ring is slidably connected with the pressure applying block, and one end of the pressure applying block is provided with a slope with elasticity, Two sides of the upper end of the first sealing plate are symmetrically provided with blocking pieces for blocking the bottom of the first branch pipe, and when the first sealing plate is in the blocking state of the water inlet, the blocking pieces are separated from the first branch pipe.

2. A smart cleaning back-flushing multi-stage centrifugal pump according to claim 1, characterized in that: One end of the second branch pipe close to the switching shell is rotatably provided with a rotating shaft, the rotating shaft is fixedly provided with a sealing ball for blocking the second branch pipe, and one side of the sealing ball is provided with a through hole.

3. A smart cleaning back-flushing multi-stage centrifugal pump according to claim 2, characterized in that: The driving source is used for driving the switching shaft and the rotating shaft to rotate alternately, the driving source comprises a transmission box arranged at the bottom of the switching shell, the lower end of the rotating shaft extends to the inner side of the transmission box and is provided with a first gear, the lower end of the switching shaft extends to the inner side of the transmission box and is provided with a second gear, the inner side of the transmission box is rotatably provided with an incomplete gear between the first gear and the second gear and used for alternately engaging with the first gear and the second gear, the bottom of the transmission box is provided with a motor used for driving the incomplete gear to rotate, when the incomplete gear completes one engagement with the second gear and the first gear, the first gear and the second gear can rotate one hundred and eighty degrees.

4. A smart cleaning back-flushing multi-stage centrifugal pump according to claim 3, characterized in that: The inner side of the switching shell is provided with a locking assembly, the locking assembly comprises a first locking disc arranged at the bottom of the first gear, the bottom of the second gear is provided with a second locking disc, one side of the second locking disc and the first locking disc is provided with an arc-shaped locking groove, the bottom of the incomplete gear is provided with a fan-shaped locking arc, and the locking arc is used for plug-in cooperation with the locking groove.

5. A smart cleaning back-flushing multi-stage centrifugal pump according to claim 1, characterized in that: The side wall of the switching shaft is provided with an opening, one end of the filter plate close to the switching shaft is provided with a second sealing plate which is arc-shaped and is in sliding cooperation with the outer wall of the switching shaft, the second sealing plate is used for plugging the opening, the connecting plate is fixed to the side wall of the second sealing plate, and one end of the connecting plate extends to the inner side of the switching shaft through the opening.

6. A smart cleaning back-flushing multi-stage centrifugal pump according to claim 1, characterized in that: The fluid is hydraulic oil.

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