CN113513482B

CN113513482B - multistage centrifugal pump

Info

Publication number: CN113513482B
Application number: CN202110546349.5A
Authority: CN
Inventors: 樊海锋; 岳娟娟
Original assignee: Zibo Huayan Pump Co ltd
Current assignee: Zibo Huayan Pump Co ltd
Priority date: 2021-05-19
Filing date: 2021-05-19
Publication date: 2023-08-22
Anticipated expiration: 2041-05-19
Also published as: CN113513482A

Abstract

The application relates to the field of multistage centrifugal pumps, and discloses a multistage centrifugal pump, wherein an annular convex block is positioned in an annular groove, a sealing cover is pressed downwards, two conical blocks are further buckled with corresponding locking blocks under the action of gravity, and the two locking springs are elastically deformed, so that the mechanical sealing and dismounting of the multistage centrifugal pump are facilitated, a top cap is pulled upwards to drive a control rod through blocking two water inlet ends, a return spring is elastically deformed, a rubber plug is separated from a circulation hole, water is injected into a pump shell through the circulation hole, a motor is started at the same time, an output end of the motor drives an input shaft to rotate through a coupler, the input shaft further enables a cam to rotate, one side of the cam contacts with a lower fixed disc during rotation, and impacts the fixed disc, and further the fixed disc generates vertical vibration along the directions of three guide rods, so that air and bubbles in the pump shell are discharged through a water outlet end, and the centrifugal pump can normally absorb and discharge liquid.

Description

Multistage centrifugal pump

Technical Field

The application relates to the field of multistage centrifugal pumps, in particular to a multistage centrifugal pump.

Background

The vertical multistage centrifugal pump is also called CDLF vertical multistage centrifugal pump, is designed and manufactured by absorbing advanced technology at home and abroad, adopts a standard vertical motor and a quick-mounting mechanical seal, is very convenient to replace, and has the characteristics of high efficiency, energy conservation, reliable quality, wide application range and the like after being put on the market. The pump is convenient to replace by adopting a standard vertical motor and a quick-assembly mechanical seal, the performance and the service life of the pump are greatly improved by adopting an excellent hydraulic model and an advanced manufacturing process, the reliability of the operation of the pump and the temperature of a conveying medium can be improved by adopting the mechanical seal made of hard alloy and fluororubber as a shaft seal, and the overflow part of the pump is formed by adopting stainless steel plate stamping and welding, so that the pump can be suitable for mild corrosive mediums, and has the advantages of compact integral structure, small volume, light weight, low noise, obvious energy-saving effect and convenient maintenance.

In the prior art, when the multistage centrifugal pump is not filled with water or is not full of water before being started, air is arranged in the pump shell, the density of the air is far smaller than that of liquid, the generated centrifugal force is very small, the centrifugal force is insufficient to enable the center of the impeller to form low pressure, the pressure difference between the liquid level and the center is very small, the liquid below the pump cannot be sucked into the pump under the action of the pressure difference, at the moment, the pump is empty and cannot absorb liquid, the discharge port cannot discharge liquid, in order to prevent abnormal operation, the centrifugal pump is required to be filled with the conveyed liquid before being started, and an independent filling inlet is not arranged in the prior art, so that the filling process before being started is complicated, on the other hand, the mechanical sealing part of the multistage centrifugal pump is inconvenient to assemble and disassemble due to the fact that the mechanical sealing part is complicated, and the mechanical sealing is easy to deviate after long-time low-frequency vibration, the sealing performance of the centrifugal pump cannot be ensured.

Disclosure of Invention

(one) solving the technical problems

Aiming at the defects of the prior art, the application provides the multistage centrifugal pump with good sealing effect, which has the advantages of good sealing performance, easy disassembly and assembly, unstable ground connection and the like, and solves the problems of poor sealing performance and difficult air discharge.

(II) technical scheme

In order to achieve the above purpose, the present application provides the following technical solutions: the multistage centrifugal pump comprises a pump shell, a rotary groove is formed in the inner wall of the bottom of the pump shell, a power shaft is connected in the rotary groove in a rotary mode, one end of the power shaft extends to the outside of the pump shell, a connecting hole is formed in one side of the power shaft, a plurality of inner impellers which are uniformly distributed are fixedly sleeved on the power shaft, outer impellers are arranged on one sides of the inner impellers, an annular groove is formed in the top of the pump shell, a sealing cover is arranged at the top of the annular groove, a rotary hole is formed in the top of the sealing cover, one end of the power shaft penetrates through the rotary hole and extends to the outside of the sealing cover, an annular lug is fixedly connected to the bottom of the sealing cover, the position of the annular lug corresponds to the position of the annular groove, an inner sealing ring is arranged on one side of the annular lug, one side of the inner sealing ring is attached to the inner wall of one side of the pump shell, sealing sleeves are fixedly connected with two arc-shaped lugs on one side of the sealing cover, conical blocks are fixedly connected to the bottom of the arc-shaped lug, one side of the sealing cover is fixedly connected with two arc-shaped lugs, and the two arc-shaped lugs are respectively corresponding to the positions of the arc-shaped lugs.

Preferably, two equal fixedly connected with thick traveller in one side of arc piece, two the circular slot has all been seted up to the one end of thick traveller, two equal fixedly connected with thin traveller in the circular slot, two equal fixedly connected with locking piece of one end of thin traveller, two the position of locking piece respectively with two the position of toper piece corresponds, the same side thick traveller with equal fixedly connected with same locking spring on the thin traveller, the same side the both ends of locking spring respectively with the arc piece the locking piece is connected.

Preferably, one side of the pump shell is provided with an upper fixing disc, the top of the upper fixing disc is fixedly connected with a connecting disc, the bottom of the upper fixing disc is fixedly connected with four stand columns, one side of the pump shell is provided with a water outlet end, the bottom of the pump shell is fixedly sleeved with a base, one side of the base is provided with two water inlet ends, the bottom of the base is fixedly connected with a lower fixing disc, and the top of the lower fixing disc is provided with three evenly distributed perforations.

Preferably, three guide rods are sleeved in the through holes in a sliding manner, two ends of the three guide rods respectively penetrate through the corresponding through holes and extend out of the through holes, the bottom ends of the three guide rods are fixedly connected with the same chassis, shaking springs are fixedly sleeved on the three guide rods, two ends of the shaking springs are respectively connected with the lower fixing disc and the chassis, and the top of the chassis is fixedly connected with a base.

Preferably, the top fixedly connected with motor of base, the output of motor passes through shaft coupling fixedly connected with input shaft, the one end fixedly connected with cam of input shaft, the position of cam with the position of pump case is corresponding, the arc wall has been seted up at the top of chassis, the position of arc wall with the position of cam is corresponding, three evenly distributed spacing holes have been seted up at the top of chassis.

Preferably, three the tip cone has all been cup jointed in the spacing downthehole slip, and is three the both ends of tip cone extend respectively to outside the corresponding spacing hole, three the equal fixedly connected with in top of tip cone two fixed blocks, two of the same position the equal fixedly connected with of one side that the fixed block is close to each other is first fixed axle, and is three all rotated on the first fixed axle and cup jointed the handle, three tip cone one side all is equipped with the supporting shoe.

Preferably, rectangular grooves are formed in the top ends of the three supporting blocks, second fixing shafts are fixedly connected in the rectangular grooves, rectangular holes are formed in one sides of the handles, the second fixing shafts are located in the rectangular holes, water inlet holes are formed in one sides of the pump shell, a guide pipe is fixedly connected to one side of the water inlet holes, and a water filling port is fixedly connected to one end of the guide pipe.

Preferably, a flow hole is formed in one end of the water injection port, the flow hole corresponds to the water inlet hole, a control rod is sleeved in the flow hole in a sliding manner, two ends of the control rod extend out of the flow hole respectively, a rubber plug is fixedly connected to one end of the control rod, and the position of the rubber plug corresponds to that of the flow hole and is adaptive to that of the flow hole.

Preferably, a top cap is fixedly connected to one end of the control rod, a reset spring is fixedly sleeved on the control rod, two ends of the reset spring are respectively connected with the water injection port and the top cap, a water injection cavity is formed in the top end of the base, and the water injection cavity is communicated with two water inlet ends.

(III) beneficial effects

Compared with the prior art, the application provides a multistage centrifugal pump, which has the following beneficial effects:

1. this multistage centrifugal pump is through being located annular groove with annular lug, presses sealed lid downwards, drives two arc lugs and toper piece, and then make two toper soon detain mutually with corresponding locking piece under the action of gravity for two locking springs take place elastic deformation, thereby the sealed dismouting of multistage centrifugal pump machinery of being convenient for.

2. According to the multistage centrifugal pump, due to the arrangement of the inner sealing ring and the sealing sleeve, the influence on the tightness of the centrifugal pump caused by the deviation of the sealing caused by long-time vibration is prevented.

3. This multistage centrifugal pump, through plugging up two water intaking ends, upwards pull out the top cap and drive the control lever, reset spring produces elastic deformation, the rubber buffer breaks away from with the circulation hole, and then water injection in to the pump case through the circulation hole, start the motor simultaneously, the output of motor drives the input shaft through the shaft coupling and rotates, the input shaft then makes the cam rotate, one side and lower fixed disk contact when the cam rotates, and strike the fixed disk, and then make the fixed disk produce vertical vibrations along three guide bar direction, thereby air and bubble in the pump case pass through the water outlet end and discharge, make the centrifugal pump can normally imbibe and flowing back.

4. This multistage centrifugal pump, through, pressing the top cap once more, through reset spring's setting, help the rubber buffer to get back to in the circulation hole for whole water injection process is more convenient.

5. This multistage centrifugal pump is through upwards mentioning three handles simultaneously for the handle uses first fixed axle and second fixed axle to rotate upwards as rotation center, and then makes the pointed cone push down through spacing hole, makes pointed cone insert ground, thereby has fixed the connected state with ground between, has guaranteed multistage centrifugal pump and has stabilized the work.

Drawings

FIG. 1 is a perspective view of a first view of the present application;

FIG. 2 is a schematic view of a second perspective view of the present application;

FIG. 3 is a partially enlarged perspective view of the structure of FIG. 1 according to the present application;

FIG. 4 is a schematic perspective view of an annular groove of the present application;

FIG. 5 is a schematic perspective view of a pump housing according to the present application;

FIG. 6 is a schematic perspective view of an inner impeller of the present application;

FIG. 7 is a schematic perspective view of an outer impeller of the present application;

FIG. 8 is a schematic perspective view of a base of the present application;

FIG. 9 is a schematic perspective view of the chassis of the present application;

FIG. 10 is a schematic perspective view of the spike cone and handle of the present application;

FIG. 11 is an enlarged perspective view of the structure of FIG. 5A according to the present application;

FIG. 12 is a schematic view of a water injection port according to the present application;

FIG. 13 is a schematic perspective view of a rubber stopper according to the present application.

In the figure: 1. a pump housing; 2. a power shaft; 3. a connection hole; 4. an inner impeller; 5. an outer impeller; 6. an annular groove; 7. sealing cover; 8. an annular bump; 9. an inner seal ring; 10. sealing sleeve; 11. arc-shaped protruding blocks; 12. a conical block; 13. an arc-shaped block; 14. a thick sliding column; 15. a fine slide column; 16. a locking block; 17. a locking spring; 18. an upper fixing plate; 19. a connecting disc; 20. a column; 21. a water outlet end; 22. a base; 23. a water inlet end; 24. a lower fixing plate; 25. perforating; 26. a guide rod; 27. a chassis; 28. a shaking spring; 29. a base; 30. a motor; 31. an input shaft; 32. a cam; 33. an arc-shaped groove; 34. a limiting hole; 35. a pointed cone; 36. a fixed block; 37. a first fixed shaft; 38. a handle; 39. a support block; 40. rectangular grooves; 41. a second fixed shaft; 42. a rectangular hole; 43. a conduit; 44. a water filling port; 45. a flow hole; 46. a control lever; 47. a rubber stopper; 48. a top cap; 49. a return spring; 50. a water injection cavity.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

As described in the background art, the present application provides a multistage centrifugal pump in order to solve the above technical problems.

In a typical implementation mode of the application, as shown in fig. 1-13, the multistage centrifugal pump comprises a pump shell 1, a rotary groove is formed in the inner wall of the bottom of the pump shell 1, a power shaft 2 is connected in a rotary mode, one end of the power shaft 2 extends out of the pump shell 1, a connecting hole 3 is formed in one side of the power shaft 2, a plurality of uniformly distributed inner impellers 4 are fixedly sleeved on the power shaft 2, outer impellers 5 are arranged on one side of the uniformly distributed inner impellers 4, an annular groove 6 is formed in the top of the pump shell 1, a sealing cover 7 is arranged at the top of the annular groove 6, a rotary hole is formed in the top of the sealing cover 7, one end of the power shaft 2 penetrates through the rotary hole and extends out of the sealing cover 7, an annular bump 8 is fixedly connected to the bottom of the sealing cover 7, the position of the annular bump 8 corresponds to the annular groove 6, one side of the annular bump 8 is provided with an inner sealing ring 9, one side of the inner sealing sleeve 10 is fixedly connected with one side of the sealing cover 7, two arc-shaped bumps 11 are fixedly connected to one side of the sealing sleeve 11, the bottoms of the two arc-shaped bumps 11 are fixedly connected with conical blocks 12, one side of the two arc-shaped bumps 1 are fixedly connected with two arc-shaped bumps 13 of the pump shell 13 respectively corresponding to the positions of the arc-shaped bumps 13.

Further, in the above scheme, the thick slide column 14 is fixedly connected with one side of two arc-shaped blocks 13, the circular slot is all seted up to the one end of two thick slide columns 14, the thin slide column 15 has all been fixedly cup jointed in two circular slots, the one end of two thin slide columns 15 is all fixedly connected with locking piece 16, the position of two locking pieces 16 respectively corresponds with the position of two toper pieces 12, the same locking spring 17 has all been fixedly cup jointed on the thick slide column 14 and the thin slide column 15 of the same side, the both ends of the locking spring 17 of same side are connected with arc-shaped block 13, locking piece 16 respectively, through the setting of arc-shaped block 13, thick slide column 14, thin slide column 15, the fixed of sealed lid 7 and spacing of being convenient for, thereby make things convenient for loading and unloading mechanical seal.

Further, in the above scheme, one side of the pump casing 1 is provided with the upper fixing plate 18, the top of the upper fixing plate 18 is fixedly connected with the connecting plate 19, the bottom of the upper fixing plate 18 is fixedly connected with the four upright posts 20, one side of the pump casing 1 is provided with the water outlet end 21, the bottom of the pump casing 1 is fixedly sleeved with the base 22, one side of the base 22 is provided with the two water inlet ends 23, the bottom of the base 22 is fixedly connected with the lower fixing plate 24, and the top of the lower fixing plate 24 is provided with the three evenly distributed perforations 25.

Further, in the above scheme, guide rods 26 are all sleeved in the three through holes 25 in a sliding manner, two ends of the three guide rods 26 respectively penetrate through corresponding through holes 25 and extend out of the through holes 25, the bottom ends of the three guide rods 26 are fixedly connected with the same chassis 27, shaking springs 28 are fixedly sleeved on the three guide rods 26, two ends of the three shaking springs 28 are respectively connected with the lower fixed disc 24 and the chassis 27, a base 29 is fixedly connected to the top of the chassis 27, and the pump shell 1 is prevented from inclining when shaking through the arrangement of the three guide rods 26.

Further, in the above-mentioned scheme, the top fixedly connected with motor 30 of base 29, the output of motor 30 passes through shaft coupling fixedly connected with input shaft 31, the one end fixedly connected with cam 32 of input shaft 31, the position of cam 32 corresponds with the position of pump case 1, arc wall 33 has been seted up at the top of chassis 27, the position of arc wall 33 corresponds with the position of cam 32, three spacing hole 34 of even distribution have been seted up at the top of chassis 27, through the setting of arc wall 33, the rotation of cam 32 is convenient for.

Further, in the above scheme, the three limiting holes 34 are all slidably sleeved with the pointed cone 35, two ends of the three pointed cones 35 extend out of the corresponding limiting holes 34 respectively, two fixing blocks 36 are fixedly connected to the top ends of the three pointed cones 35, first fixing shafts 37 are fixedly connected to one sides, close to each other, of the two fixing blocks 36 at the same position, handles 38 are rotatably sleeved on the three first fixing shafts 37, supporting blocks 39 are arranged on one sides of the three pointed cones 35, and the whole multistage centrifugal pump device can be fixed in the ground through the arrangement of the three pointed cones 35.

Further, in the above-mentioned scheme, rectangular slot 40 has all been seted up on the top of three supporting shoe 39, all fixedly connected with second fixed axle 41 in the three rectangular slot 40, rectangular hole 42 has all been seted up to one side of three handle 38, three second fixed axle 41 of coplanar position all are located three rectangular hole 42, the inlet opening has been seted up to one side of pump case 1, one side fixedly connected with pipe 43 of inlet opening, the one end fixedly connected with water injection mouth 44 of pipe 43, through the setting of handle 38, first fixed axle 37 and second fixed axle 41, the pointed cone 35 of being convenient for inserts ground.

Further, in the above-mentioned scheme, the one end of water injection port 44 has been seted up and has been flowed through hole 45, and the flow through hole 45 corresponds with the inlet port, has been slided and has been cup jointed control lever 46 in the flow through hole 45, and the both ends of control lever 46 extend to the flow through hole 45 respectively outward, and the one end fixedly connected with rubber stopper 47 of control lever 46, the position of rubber stopper 47 corresponds with the position of flow through hole 45, and looks adaptation.

Further, in the above-mentioned scheme, the top cap 48 is fixedly connected with one end of the control rod 46, the reset spring 49 is fixedly sleeved on the control rod 46, two ends of the reset spring 49 are respectively connected with the water injection port 44 and the top cap 48, the water injection cavity 50 is formed in the top end of the base 22, the water injection cavity 50 is communicated with the two water inlet ends 23, and the water injection port 44, the circulation hole 45, the control rod 46, the rubber plug 47 and the reset spring 49 are arranged, so that water injection is facilitated, air in the pump shell 1 is discharged, and liquid suction and liquid discharge of the centrifugal pump are facilitated.

When the multistage centrifugal pump is used, the annular convex blocks 8 are positioned in the annular groove 6, the sealing cover 7 is pressed downwards, the two arc convex blocks 11 and the conical blocks 12 are driven, the two conical blocks 12 are further buckled with the corresponding locking blocks 16 under the action of gravity, and the two locking springs 17 are elastically deformed, so that the sealing disassembly and assembly of the multistage centrifugal pump machinery are facilitated; meanwhile, due to the arrangement of the inner sealing ring 9 and the sealing sleeve 10, the influence of the sealing property of the centrifugal pump caused by the deviation of the sealing due to long-time vibration is prevented; the two water inlet ends 23 are plugged, the top cap 48 is pulled upwards to drive the control rod 46, the reset spring 49 generates elastic deformation, the rubber plug 47 is separated from the circulation hole 45, water is injected into the pump shell 1 through the circulation hole 45, meanwhile, the motor 30 is started, the output end of the motor 30 drives the input shaft 31 to rotate through the coupler, the input shaft 31 further enables the cam 32 to rotate, one side of the cam 32 contacts with the lower fixed disc 24 during rotation, the fixed disc 24 is impacted, the fixed disc 24 is further enabled to vibrate vertically along the directions of the three guide rods 26, and accordingly air and bubbles in the pump shell 1 are discharged through the water outlet ends 21, and the centrifugal pump can absorb and discharge liquid normally.

After the air is exhausted, the top cap 48 is pressed again, and the rubber plug 47 is helped to return to the flow hole 45 through the arrangement of the reset spring 49, so that the whole water injection process is more convenient; simultaneously, three handles 38 are lifted upwards, so that the handles 38 rotate upwards by taking the first fixing shaft 37 and the second fixing shaft 41 as rotation centers, and then the pointed cone 35 is pressed downwards through the limiting hole 34, and the pointed cone 35 is inserted into the ground, thereby fixing the connection state with the ground, and ensuring the stable operation of the multistage centrifugal pump.

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

Claims

1. Multistage centrifugal pump, including pump case (1), its characterized in that: the utility model discloses a pump casing, including pump casing (1) and sealing cover (7), the inner wall of the bottom of pump casing (1) has seted up the change groove, the change inslot rotation is connected with power shaft (2), the one end of power shaft (2) extends to outside pump casing (1), connecting hole (3) have been seted up to one side of power shaft (2), fixed cover has been connected a plurality of even inner impellers (4) on power shaft (2), a plurality of even inner impellers (4) all are equipped with outer impeller (5) in one side, annular groove (6) have been seted up at pump casing (1) top, the top of annular groove (6) is equipped with sealed lid (7), the change hole has been seted up at the top of sealed lid (7), the one end of power shaft (2) runs through the change hole extends to outside sealed lid (7), the bottom fixedly connected with annular bump (8) of sealed lid (7), the position of annular bump (8) corresponds, and looks adaptation, one side of annular bump (8) is equipped with inner seal (9), one side of inner impeller (4) all is equipped with outer impeller (5), one side of inner seal (1) is equipped with sealed lid (11) and two arc-shaped connection (11) have, two arc-shaped seal cover (11) are connected fixedly, two arc blocks (13) are fixedly connected to one side of the pump shell (1), and the positions of the two arc blocks (13) correspond to the positions of the two arc protruding blocks (11) respectively; two equal fixedly connected with thick traveller (14) in one side of arc piece (13), two the circular slot has all been seted up to the one end of thick traveller (14), two equal fixedly connected with thin traveller (15) in the circular slot, two the equal fixedly connected with locking piece (16) of one end of thin traveller (15), two the position of locking piece (16) respectively with two the position of toper piece (12) corresponds, with one side thick traveller (14) with all fixedly cup joint same locking spring (17) on thin traveller (15), with one side the both ends of locking spring (17) respectively with arc piece (13) locking piece (16) are connected.

2. The multistage centrifugal pump according to claim 1, wherein: one side of pump case (1) is equipped with fixed disk (18), the top fixedly connected with connection pad (19) of going up fixed disk (18), the bottom fixedly connected with four stand (20) of going up fixed disk (18), go out water end (21) have been seted up to one side of pump case (1), the bottom fixed sleeve of pump case (1) has base (22), two water inlet ends (23) have been seted up to one side of base (22), the bottom fixedly connected with of base (22) is fixed disk (24) down, three perforation (25) of evenly distributed have been seted up at the top of fixed disk (24) down.

3. The multistage centrifugal pump according to claim 2, wherein: three guide rods (26) are sleeved in the through holes (25) in a sliding mode, the two ends of the guide rods (26) penetrate through the corresponding through holes (25) respectively and extend out of the through holes (25), the bottom ends of the guide rods (26) are fixedly connected with the same chassis (27), shaking springs (28) are fixedly sleeved on the guide rods (26), the two ends of the shaking springs (28) are connected with the lower fixing disc (24) and the chassis (27) respectively, and bases (29) are fixedly connected to the tops of the chassis (27).

4. A multistage centrifugal pump according to claim 3, wherein: the top fixedly connected with motor (30) of base (29), the output of motor (30) is through shaft coupling fixedly connected with input shaft (31), the one end fixedly connected with cam (32) of input shaft (31), the position of cam (32) with the position of pump case (1) is corresponding, arc wall (33) have been seted up at the top of chassis (27), the position of arc wall (33) with the position of cam (32) is corresponding, three spacing hole (34) of evenly distributed have been seted up at the top of chassis (27).

5. The multistage centrifugal pump according to claim 4, wherein: three tip cone (35) have all been slided and sleeved in spacing hole (34), three tip cone (35) both ends extend respectively to corresponding outside spacing hole (34), three tip cone (35)'s top all fixedly connected with two fixed blocks (36), two of coplanar one side that fixed block (36) are close to each other all fixedly connected with first fixed axle (37), three all rotate on first fixed axle (37) and cup joint handle (38), three tip cone (35) one side all is equipped with supporting shoe (39).

6. The multistage centrifugal pump according to claim 5, wherein: rectangular grooves (40) are formed in the top ends of the supporting blocks (39), second fixing shafts (41) are fixedly connected in the rectangular grooves (40), rectangular holes (42) are formed in one sides of the handles (38), the second fixing shafts (41) are located in the rectangular holes (42), water inlets are formed in one sides of the pump shell (1), guide pipes (43) are fixedly connected to one sides of the water inlets, and water injection ports (44) are fixedly connected to one ends of the guide pipes (43).

7. The multistage centrifugal pump according to claim 6, wherein: one end of the water injection port (44) is provided with a flow hole (45), the flow hole (45) corresponds to the water inlet hole, a control rod (46) is sleeved in the flow hole (45) in a sliding way, the two ends of the control rod (46) extend out of the circulation hole (45) respectively, one end of the control rod (46) is fixedly connected with a rubber plug (47), and the position of the rubber plug (47) corresponds to the position of the circulation hole (45) and is matched with the position of the circulation hole.

8. The multistage centrifugal pump according to claim 7, wherein: one end fixedly connected with hood (48) of control lever (46), fixed sleeve has reset spring (49) on control lever (46), reset spring (49) both ends respectively with water injection mouth (44) hood (48) are connected, water injection chamber (50) have been seted up on the top of base (22), water injection chamber (50) are linked together with two water inlet (23).