Direct connection type vertical multi-stage centrifugal pump

Abstract

The utility model discloses a direct connection type vertical multi-stage centrifugal pump, which relates to the technical field of pumps, and comprises a driving part and a pump body, according to the technical scheme, the connecting groove is formed in the driving shaft, and one end of the pump shaft extends into the connecting groove and is connected with the driving shaft, so that the driving shaft and the pump shaft are coaxial, when the pump body goes wrong and needs to be repaired, maintenance of the centrifugal pump can be achieved only by disassembling a part, the maintenance quality and effect are improved, and the maintenance cost is reduced. And one end of the pump shaft is arranged to be the circular truncated cone, so that in the rotary connection process of the pump shaft, the axis of the pump shaft and the axis of the driving shaft are gradually overlapped, the overlap ratio of the axis of the pump shaft and the axis of the driving shaft is increased, vibration and abnormal sound during working of the centrifugal pump are avoided, and the working stability of the centrifugal pump is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of pumps, in particular to a direct-connected vertical multi-stage centrifugal pump. Background Art

[0002] In order to ensure the assembly efficiency of the pump body, there is an integrated structural design of the pump shaft and the drive shaft, which can realize the installation of the pump shaft and the drive shaft at the same time, eliminating the process of matching the drive shaft and the pump shaft.

[0003] However, due to the different pump powers, the length of the pump shaft is also different. If the pump shaft is too long, the concentricity is difficult to ensure, which increases the difficulty of pump shaft processing. Moreover, when the pump has problems and needs maintenance, the pump needs to be disassembled as a whole, which greatly increases the workload and difficulty of the maintenance personnel, and is not conducive to improving maintenance efficiency. Utility Model Content

[0004] The main purpose of the utility model is to propose a direct-connected vertical multi-stage centrifugal pump, which aims to connect the motor and the pump shaft, ensure concentricity, reduce the maintenance difficulty of the rational pump, and improve maintenance efficiency.

[0005] To achieve the above-mentioned purpose, the utility model proposes a direct-connected vertical multi-stage centrifugal pump, comprising:

[0006] A driving portion, wherein the driving portion is provided with a driving shaft, and the driving shaft is provided with a connecting groove;

[0007] A pump body, the pump body being connected to the driving part, the pump body being provided with a pump shaft, one end of the pump shaft being plugged into the connecting groove;

[0008] The end of the pump shaft inserted into the connecting groove is in a truncated cone shape, and a plurality of abutment portions are inserted into the drive shaft at intervals, and the plurality of abutment portions are all in abutment with the pump shaft.

[0009] In one embodiment, a tooth portion is provided on a side of the abutting portion facing the pump shaft.

[0010] In one embodiment, a first water inlet and outlet and a second water inlet and outlet are respectively provided on two opposite sides of the pump body, the first water inlet and outlet are provided between the driving part and the pump body, the side surface of the first water inlet and outlet is concave to form a processing cavity, the driving shaft passes through the processing cavity, and the abutment portion is located in the processing cavity.

[0011] In one embodiment, a first flow cavity is provided in the first water inlet and outlet, a first water inlet and outlet is provided on a side of the first water inlet and outlet, the first water inlet and outlet is connected to the first flow cavity, and a spoiler is provided in the first flow cavity.

[0012] In one embodiment, the width of the spoiler in the extending direction of the drive shaft is smaller than the inner diameter of the first flow cavity in the extending direction of the drive shaft.

[0013] In one embodiment, a first drain port is provided in the first water inlet and outlet portion, the first drain port is connected to the first flow cavity, and a first plug is provided in the first flow cavity.

[0014] In one embodiment, a second flow cavity is provided in the second water inlet and outlet, a second water inlet and outlet is provided on the side of the second water inlet and outlet, the second water inlet and outlet is connected to the second flow cavity, the second water inlet and outlet is provided with a water discharge channel, and a second plug is provided in the water discharge channel.

[0015] In one embodiment, the pump shaft passes through the pump body, a plurality of impellers are spaced apart on the pump shaft within the pump body, and a limiting portion is connected to one end of the pump shaft away from the driving portion.

[0016] In one embodiment, the limiting portion is provided with a plurality of clamping surfaces, and the plurality of clamping surfaces are arranged at intervals.

[0017] In one embodiment, an isolation cover is provided on the side of the driving portion facing away from the pump body, and a steering groove is provided on the isolation cover.

[0018] The technical solution of the present invention is to provide a connecting groove on the drive shaft, and one end of the pump shaft extends into the connecting groove and is connected to the drive shaft to achieve coaxiality between the drive shaft and the pump shaft. This is so that when a problem occurs with the pump body and needs to be repaired, only part of the pump body needs to be disassembled to achieve maintenance of the centrifugal pump, thereby improving the quality and effect of maintenance. In addition, one end of the pump shaft is set to a frustum, so that during the process of rotating the pump shaft, the axis center line of the pump shaft and the axis center line of the drive shaft gradually coincide with each other, thereby improving the coincidence degree between the axis center line of the pump shaft and the axis center line of the drive shaft, avoiding vibration and abnormal noise during the operation of the centrifugal pump, and ensuring the stability of the operation of the centrifugal pump. At the same time, multiple abutment parts are provided on the drive shaft, and the multiple abutment parts all abut against the pump shaft. By adjusting the position of the abutment part relative to the pump shaft, the position of the axis center line of the abutment part is adjusted to ensure the coaxiality between the drive shaft and the pump shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1A schematic structural diagram of an embodiment of a direct-connected vertical multi-stage centrifugal pump provided by the present utility model;

[0021] Figure 2 A schematic structural diagram of another embodiment of the direct-connected vertical multi-stage centrifugal pump provided by the present invention;

[0022] Figure 3 A schematic structural diagram of another embodiment of the direct-connected vertical multi-stage centrifugal pump provided by the present utility model;

[0023] Figure 4 for Figure 2 Enlarged cross-sectional view at AA in the middle;

[0024] Figure 5 for Figure 3 Enlarged cross-sectional view of the middle BB;

[0025] Figure 6 for Figure 2 Enlarged cross-sectional view at CC;

[0026] Figure 7 for Figure 5 A partial enlarged view of point D in the middle;

[0027] Figure 8 This is a structural schematic diagram of a restriction portion in an embodiment of a direct-connected vertical multi-stage centrifugal pump provided by the present invention;

[0028] Figure 9 This is a schematic top view of the structure of an embodiment of a direct-connected vertical multi-stage centrifugal pump provided by the utility model.

[0029] Description of Figure Numbers:

[0030] 100. Direct-coupled vertical multi-stage centrifugal pump; 10. Driving unit; 11. Driving body; 12. Driving shaft; 13. Abutting unit; 14. Connecting groove; 15. Through hole; 20. First water inlet and outlet; 21. First plug; 22. First water inlet and outlet body; 23. Spoiler; 24. First flow chamber; 25. Processing chamber; 30. Pump body; 31. Pump shaft; 32. Impeller; 33. Restricting unit; 34. Clamping surface; 40. Second water inlet and outlet; 41. Second flow chamber; 42. Second water inlet and outlet body; 43. Second plug; 44. Discharge channel.

[0031] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] The utility model provides a direct-connected vertical multi-stage centrifugal pump.

[0036] See also Figure 1 In one embodiment of the present invention, the direct-connected vertical multi-stage centrifugal pump comprises:

[0037] A driving portion 10, wherein the driving portion 10 is provided with a driving shaft 12, and the driving shaft 12 is provided with a connecting groove 14;

[0038] A pump body 30 is connected to the driving unit 10 . A pump shaft 31 is provided on the pump body 30 . One end of the pump shaft 31 is inserted into the connecting groove 14 .

[0039] The end of the pump shaft 31 inserted into the connecting groove 14 is in a truncated cone shape. A plurality of abutting portions 13 are inserted into the drive shaft 12 at intervals, and all of the abutting portions 13 abut against the pump shaft 31 .

[0040] It should be noted that the driving unit 10 includes a driving body 11 , and the driving body 11 is dynamically connected to the driving shaft 12 .

[0041] It can be understood that the driving part 10 is a motor, the driving shaft 12 is a driving shaft, and the driving part 10 outputs power to drive the driving shaft to rotate, thereby driving the pump shaft 31 to rotate, so as to achieve normal operation of the centrifugal pump.

[0042] like Figure 7 As shown, the drive shaft 12 is provided with a plurality of through holes 15 , each of the through holes 15 is provided with the abutment portion 13 , the through holes 15 are connected to the connecting groove 14 , and the abutment portion 13 abuts against the pump shaft 31 .

[0043] It can be understood that by setting the abutment portion 13, the displacement of the abutment portion 13 in the through hole 15 is adjusted, and then the abutment force of the abutment portion 13 on the pump shaft 31 is adjusted. Under the joint action of multiple abutment portions 13, the axis between the drive shaft 12 and the pump shaft 31 is adjusted to ensure that the drive shaft 12 and the pump shaft 31 are coaxial.

[0044] In order to ensure that the axis between the drive shaft 12 and the pump shaft 31 is adjusted, as shown in FIG. Figure 7 As shown, there are two abutting portions 13 and two through holes 15 , and the two through holes 15 are oppositely arranged on the driving shaft 12 .

[0045] It can be understood that the two abutment portions 13 arranged relatively in the through hole 15 act together on the pump shaft 31. By adjusting the two relatively arranged abutment portions 13, the axis center of the pump shaft 31 can be adjusted so as to better match the concentricity with the drive shaft 12, and the abutment portions 13 can limit the separation of the drive shaft 12 and the pump shaft 31 during the reverse rotation.

[0046] It should be noted that the number of the through holes 15 and the abutting portions 13 are both even, and they are symmetrically arranged in pairs to ensure calibration quality.

[0047] It can be understood that the abutting portion 13 is screw-fitted into the through hole 15 , so that the position of the abutting portion 13 in the through hole 15 can be adjusted by rotating the abutting portion 13 .

[0048] It can be understood that the drive shaft 12 and the pump shaft 31 are threaded together, and one end of the pump shaft 31 is a frustum. During the rotation of the pump shaft 31, the pump shaft 31 is automatically aligned with the axis of the drive shaft 12 through the inclined surface.

[0049] It should be noted that the thread provided on one end of the drive shaft 12 is a reverse thread, which ensures that the drive shaft 12 and the pump shaft 31 are more closely matched during rotation, thereby improving the fixing effect.

[0050] The technical solution of the present invention is to provide the connecting groove 14 on the drive shaft 12, and one end of the pump shaft 31 extends into the connecting groove 14 and is connected to the drive shaft 12, so as to realize the coaxiality of the drive shaft 12 and the pump shaft 31. In order to facilitate the maintenance of the centrifugal pump by only disassembling part when a problem occurs in the pump body and needs to be repaired, the quality and effect of the maintenance are improved. In addition, one end of the pump shaft 31 is set as a frustum, so that during the rotation connection of the pump shaft 31, the axis of the pump shaft 31 is aligned with the axis of the pump shaft 31. The axis center lines of the drive shaft 12 gradually overlap, thereby increasing the degree of overlap between the axis center lines of the pump shaft 31 and the axis center lines of the drive shaft 12, avoiding vibration and abnormal noise during the operation of the centrifugal pump, and ensuring the stability of the operation of the centrifugal pump. At the same time, a plurality of abutment portions 13 are provided on the drive shaft 12, and the plurality of abutment portions 13 abut against the pump shaft 31. By adjusting the position of the abutment portion 13 relative to the pump shaft 31, the position of the axis center line of the abutment portion 13 is adjusted to ensure the coaxiality between the drive shaft 12 and the pump shaft 31.

[0051] In one embodiment, a tooth portion is provided on a side of the abutting portion 13 facing the pump shaft 31 .

[0052] like Figure 7 As shown, a plurality of teeth are provided at intervals on the side of the abutting portion 13 facing the pump shaft 31 , and one end of the teeth facing away from the abutting portion 13 abuts against the pump shaft 31 .

[0053] It can be understood that by providing a plurality of the teeth, when the abutting portion 13 is rotated, the teeth abut against the pump shaft 31 and the force acting on the pump shaft 31 is increased.

[0054] It can be understood that when the drive shaft 12 drives the pump shaft 31 to rotate forward and reverse, the abutment force between the tooth portion and the pump shaft 31 limits the pump shaft 31 from rotating relative to the drive shaft 12 when the drive shaft 12 rotates, thereby ensuring the consistency of movement between the pump shaft 31 and the drive shaft 12 and ensuring work quality and efficiency.

[0055] It should be noted that the tooth portion has a sharp end to prevent relative movement between the tooth portion and the pump shaft 31 from affecting power transmission between the drive shaft 12 and the pump shaft 31 .

[0056] In one embodiment, a first water inlet and outlet portion 20 and a second water inlet and outlet portion 40 are respectively provided on two opposite sides of the pump body 30. The first water inlet and outlet portion 20 is provided between the driving portion 10 and the pump body 30. The side surface of the first water inlet and outlet portion 20 is concave to form a processing cavity 25. The driving shaft 12 passes through the processing cavity 25, and the abutment portion 13 is located in the processing cavity 25.

[0057] like Figures 1 to 5 As shown, when the centrifugal pump is working, the driving part 10 drives the driving shaft 12 to rotate, and then drives the pump shaft 31 to rotate, so that the liquid passes through the second water inlet and outlet part 40 and the pump body 30, and leaves the water pump through the first water inlet and outlet part 20.

[0058] In order to facilitate the staff to operate the abutment portion 13 , the side surface of the first water inlet and outlet portion 20 is concave to form the processing cavity 25 . When the drive shaft 12 passes through the processing cavity 25 , the abutment portion 13 is located in the processing cavity 25 .

[0059] It can be understood that the processing chamber 25 is concave and accommodates part of the drive shaft 12, so that the staff can directly reach into the processing chamber 25 to operate the abutment portion 13, facilitate the adjustment between the axis center line of the pump shaft 31 and the axis center line of the drive shaft 12, and improve the adjustment efficiency.

[0060] It should be noted that, in order to facilitate the operation of the abutment portion 13 in the drive shaft 12 , a groove is provided on the side of the abutment portion 13 away from the pump shaft 31 , so as to facilitate the operation of the abutment portion 13 by an operating tool.

[0061] In one embodiment, a first flow cavity 24 is provided in the first water inlet and outlet portion 20 , a first water inlet and outlet is provided on the side of the first water inlet and outlet portion 20 , the first water inlet and outlet is connected to the first flow cavity 24 , and a spoiler 23 is provided in the first flow cavity 24 .

[0062] It can be understood that the first water inlet and outlet portion 20 includes a first water inlet and outlet body 22 , and the first flow cavity 24 is provided in the first water inlet and outlet body 22 .

[0063] like Figure 4 and Figure 6 As shown, the liquid enters the first flow cavity 24 through the pump body 30 and leaves through the first water inlet and outlet, thereby realizing normal operation of the centrifugal pump.

[0064] It should be noted that, when the centrifugal pump is working, the liquid is output in a rotating manner, so the liquid in the first flow chamber 24 is prone to form a vortex-like fluid, which affects the normal output of the liquid.

[0065] It is understandable that a spoiler 23 is provided in the first flow chamber 24 to disrupt the rotating flow of the fluid and break up the refluxed liquid, thereby ensuring the normal output of the liquid and improving the output quality and efficiency.

[0066] It should be noted that, in order to improve the disturbance quality, the spoiler 23 is arranged on a side close to the first water inlet and outlet, so that the spoiler 23 can disrupt the liquid reflux state at the position of the first water inlet and outlet to ensure the liquid discharge efficiency.

[0067] In one embodiment, the width of the spoiler 23 in the extending direction of the drive shaft 12 is smaller than the inner diameter of the first flow cavity 24 in the extending direction of the drive shaft 12 .

[0068] like Figure 5 and Figure 6 As shown, the spoiler 23 does not completely block the flow direction of the liquid in the first flow chamber 24, so that the normally flowing liquid and the disturbed liquid flow relative to each other, further disrupting the water flow, avoiding the occurrence of vortices, improving the disruption effect, reducing the production cost of the spoiler 23 and improving assembly efficiency.

[0069] In one embodiment, a first drain port is provided in the first water inlet and outlet portion 20 , the first drain port is connected to the first flow cavity 24 , and a first plug 21 is provided in the first drain port.

[0070] It can be understood that the first drain port is connected to the outside. When the liquid in the pump body 30 needs to be discharged, by removing the first plug 21 in the first drain port, the liquid can be assisted to flow out from the first drain port when the pump body 30 is not working, thereby avoiding liquid residue.

[0071] It should be noted that the first plug 21 is detachably connected to the first drain outlet.

[0072] It can be understood that the first plug 21 is spirally connected to the first drain outlet, and the first plug 21 can be tightened or loosened by rotation, which facilitates the disassembly and assembly of the first plug 21.

[0073] In one embodiment, a second flow cavity 41 is provided in the second water inlet and outlet part 40, a second water inlet and outlet is provided on the side of the second water inlet and outlet part 40, the second water inlet and outlet is communicated with the second flow cavity 41, and a water discharge channel 44 is provided in the second water inlet and outlet part 40, and a second plug 43 is provided in the water discharge channel 44.

[0074] like Figure 4As shown, the second water inlet and outlet part 40 includes a second water inlet and outlet body 42 and a second flow cavity 41. The second flow cavity 41 is arranged in the second water inlet and outlet body 42. The pump body 40 is connected to the second water inlet and outlet body 42, and the second flow cavity 41 is connected to the internal space of the pump body 40. A second water inlet and outlet is provided on the side of the second water inlet and outlet body 42.

[0075] It can be understood that when the driving part 10 is working, the driving shaft 12 drives the pump shaft 31 to rotate, and then drives the impeller 32 to rotate, so that the liquid enters the pump body 30 from the second water inlet and outlet, and leaves from the first water inlet and outlet.

[0076] It is understandable that in order to prevent liquid from remaining in the pump body 30, the drain channel 44 is set in the second water inlet and outlet part so that the liquid can leave the pump body 30 through the drain channel 44, thereby preventing the liquid from freezing and solidifying in a low temperature environment and causing damage to the pump body 30.

[0077] In one embodiment, the pump shaft 31 passes through the pump body 30 , a plurality of impellers 32 are spaced apart on the pump shaft 31 in the pump body 30 , and a limiting portion 33 is connected to one end of the pump shaft 31 away from the driving portion 10 .

[0078] like Figure 4 and Figure 6 As shown, the pump shaft 31 is passed through the first water inlet and outlet 20 and the pump body 30, and a sealing coil is connected between the pump shaft 31 and the first water inlet and outlet 20 to prevent liquid from leaking from the gap between the pump shaft 31 and the first water inlet and outlet 20, thereby ensuring the efficiency of the centrifugal pump.

[0079] It can be understood that the multiple impellers 32 are arranged at intervals on the pump shaft 31 in the pump body 30, so that the multiple impellers 32 are driven to rotate synchronously during the rotation of the pump shaft 31, thereby facilitating the suction of liquid into the pump body 30 and realizing the normal operation of the centrifugal pump.

[0080] In order to prevent the multiple impellers 32 from detaching from the pump shaft 31, the limiting portion 33 is connected to the end of the pump shaft 31 away from the first water inlet and outlet, so that the first impeller 32 is restricted on the pump shaft 31, ensuring that the remaining multiple impellers 32 are restricted on the pump shaft 31, thereby facilitating the transmission between the pump shaft 31 and the multiple impellers 32.

[0081] It should be noted that the limiting portion abuts against the first impeller, and a nut is connected to the end of the pump shaft 31 to further limit the limiting portion, thereby increasing the limit of the impeller 32 by the limiting force.

[0082] It is understandable that when the nut needs to be removed, the limiting portion 33 can be restricted so that during the rotation of the nut, the limiting portion 33 and the pump shaft 31 cannot rotate with the rotation of the nut, thereby ensuring that the nut can be loaded and unloaded normally and quickly, thereby improving the efficiency of loading and unloading.

[0083] In one embodiment, the limiting portion 33 is provided with a plurality of clamping surfaces 34 , and the plurality of clamping surfaces 34 are arranged at intervals.

[0084] like Figure 8 As shown, there are two clamping surfaces 34, and the two clamping surfaces 34 are arranged opposite to each other, which makes it convenient for objects such as a wrench to clamp the limiting portion 33, preventing the limiting portion 33 and the pump shaft 31 from rotating synchronously with the rotation of the nut, thereby ensuring the disassembly and assembly efficiency of the nut.

[0085] It should be noted that the clamping surface 34 is a plane to ensure the clamping stability of tools such as wrenches.

[0086] In one embodiment, an isolation cover is provided on the side of the driving portion 10 facing away from the pump body 30 , and a deflection groove 16 is provided on the isolation cover.

[0087] It should be noted that after the centrifugal pump is assembled, the rotor needs to be cranked. However, the tail of a general centrifugal pump has a mesh, which makes it inconvenient to crank the rotor.

[0088] It can be understood that the turning groove 16 is provided in the center of the isolation cover to facilitate the straight line to pass through the isolation cover and be inserted into the groove at the tail of the drive shaft for rotation, thereby realizing the turning of the rotor, eliminating the process of disassembling and assembling the drive part 10, and improving the efficiency of the centrifugal pump after assembly.

[0089] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A direct-connected vertical multi-stage centrifugal pump, characterized in that: include: A driving portion, wherein the driving portion is provided with a driving shaft, and the driving shaft is provided with a connecting groove; A pump body, the pump body being connected to the driving part, the pump body being provided with a pump shaft, one end of the pump shaft being plugged into the connecting groove; The end of the pump shaft inserted into the connecting groove is in a truncated cone shape, and a plurality of abutment portions are inserted into the drive shaft at intervals, and the plurality of abutment portions are all in abutment with the pump shaft.

2. The direct-connected vertical multi-stage centrifugal pump according to claim 1, characterized in that: A tooth portion is provided on a side of the abutting portion facing the pump shaft.

3. The direct-connected vertical multi-stage centrifugal pump according to claim 1, characterized in that: A first water inlet and outlet and a second water inlet and outlet are respectively provided on two opposite sides of the pump body. The first water inlet and outlet are provided between the driving part and the pump body. The side surfaces of the first water inlet and outlet are concave to form a processing cavity. The driving shaft passes through the processing cavity, and the abutment portion is located in the processing cavity.

4. The direct-connected vertical multi-stage centrifugal pump according to claim 3, characterized in that: A first flow cavity is provided in the first water inlet and outlet part, a first water inlet and outlet is provided on the side of the first water inlet and outlet part, the first water inlet and outlet is connected to the first flow cavity, and a spoiler is provided in the first flow cavity.

5. The direct-connected vertical multi-stage centrifugal pump according to claim 4, characterized in that: A width of the spoiler in the extending direction of the drive shaft is smaller than an inner diameter of the first flow chamber in the extending direction of the drive shaft.

6. The direct-connected vertical multi-stage centrifugal pump according to claim 4, characterized in that: A first drain port is provided in the first water inlet and outlet portion, the first drain port is connected to the first flow cavity, and a first plug is provided in the first flow cavity.

7. The direct-connected vertical multi-stage centrifugal pump according to claim 3, characterized in that: A second flow cavity is provided in the second water inlet and outlet part, a second water inlet and outlet is provided on the side of the second water inlet and outlet part, the second water inlet and outlet is connected to the second flow cavity, the second water inlet and outlet part is provided with a water discharge channel, and a second plug is provided in the water discharge channel.

8. The direct-connected vertical multi-stage centrifugal pump according to claim 3, characterized in that: The pump shaft passes through the pump body, a plurality of impellers are arranged at intervals on the pump shaft located in the pump body, and a limiting portion is connected to one end of the pump shaft away from the driving portion.

9. The direct-connected vertical multi-stage centrifugal pump according to claim 8, characterized in that: The limiting portion is provided with a plurality of clamping surfaces, and the plurality of clamping surfaces are arranged at intervals.

10. The direct-connected vertical multi-stage centrifugal pump according to claim 1, characterized in that: An isolation cover is provided on the side of the driving portion facing away from the pump body, and a steering groove is provided on the isolation cover.

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