Multistage centrifugal pump

Abstract

The application relates to the technical field of centrifugal pumps, and discloses a multistage centrifugal pump which comprises a water inlet section, a primary impeller, a guide vane, a middle section, a secondary impeller, a final-stage impeller, a water outlet section, the water inlet section is provided with a water inlet anti-swirl rib, the water outlet section is provided with a water outlet anti-swirl rib, the middle section is provided with a middle anti-swirl rib, the water inlet anti-swirl rib cooperates with the guide vane, the primary impeller and the water inlet section to form a first anti-swirl front cavity, the middle anti-swirl rib cooperates with the guide vane, the secondary impeller and the middle section to form a second anti-swirl front cavity, the middle anti-swirl rib cooperates with the final-stage impeller and the water outlet section to form a third anti-swirl front cavity, and the water outlet anti-swirl rib cooperates with the final-stage impeller to form an anti-swirl rear cavity. Compared with the prior art, the multistage centrifugal pump significantly reduces liquid rotation driven by impeller rotation, reduces hydraulic loss caused by liquid rotation, improves the efficiency of the water pump, and reduces the vibration of the water pump, which is beneficial to improving the stability of the water pump and ensuring normal operation of the water pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of centrifugal pumps, in particular to a multi-stage centrifugal pump. BACKGROUND

[0002] The centrifugal pump refers to a pump for conveying liquid by centrifugal force generated by rotation of an impeller. The multi-stage centrifugal pump is a pump in which two or more centrifugal pumps having the same function are combined together, and the fluid passage structure is such that the medium pressure relief port of the first stage is communicated with the inlet of the second stage, and the medium pressure relief port of the second stage is communicated with the inlet of the third stage, and each structure is arranged in series. The multi-stage centrifugal pump can improve the set pressure and meet the requirements of some special application occasions.

[0003] The existing multi-stage centrifugal pump has a large number of impeller stages. Rotation of the impeller causes rotation of the liquid in the impeller cavity, and a large amount of liquid rotation forms a hydraulic vortex loss, thereby reducing the efficiency of the multi-stage pump. Further, the vortex formed by rotation also causes unstable flow of the liquid, increases vibration of the water pump, and reduces the operation reliability of the water pump. Furthermore, the increase in the number of impeller stages also causes the pump shaft to be too long, and the flushing and lubrication effect of the sliding bearing is poor. The slight change of the long pump shaft increases the wear of the sliding bearing, and reduces the service life of the water pump or directly damages the water pump.

[0004] In addition, due to the large number of impeller stages of the multi-stage pump, the pump has a high lift, and a large axial force is generated during operation. In the prior art, high-pressure liquid is usually used to balance and relieve the axial force. This part of high-pressure liquid is not fully utilized, and the high-pressure liquid is directly leaked into the suction inlet of the water inlet section, causing the motor of the water pump to do useless work, wasting energy, increasing the operation cost of the water pump, and unbalanced axial force of the multi-stage pump also causes the water pump bearing to bear too large axial thrust, high bearing temperature, operation vibration, large noise and easy damage, which also affects the normal use of the pump. SUMMARY

[0005] To solve the above technical problems, the purpose of the present application is to provide a multi-stage centrifugal pump which has the advantages of ingenious structure design, small degree of liquid rotation, etc.

[0006] Based on this, the application provides a multistage centrifugal pump, which comprises a water inlet section, a primary impeller, a guide vane, a middle section, a secondary impeller, a final-stage impeller, a water outlet section, a balance hub, a mechanical seal seat, a set-type mechanical seal, a pump shaft, a sliding bearing cover, a sliding bearing, a sliding bearing sleeve, a bearing box support, a shaft coupling and a motor, the water inlet section is provided with a water inlet anti-swirl rib, the water outlet section is provided with a water outlet anti-swirl rib, and the middle section is provided with a middle anti-swirl rib; the water inlet anti-swirl rib, the guide vane, the primary impeller and the water inlet section cooperatively form a first anti-swirl front cavity covering the primary impeller, the middle anti-swirl rib, the guide vane, the secondary impeller and the middle section cooperatively form a second anti-swirl front cavity covering the secondary impeller, the middle anti-swirl rib, the final-stage impeller and the water outlet section cooperatively form a third anti-swirl front cavity covering the final-stage impeller, and the water outlet anti-swirl rib and the final-stage impeller cooperatively form an anti-swirl rear cavity covering the final-stage impeller.

[0007] In some embodiments of the application, the water inlet section is further provided with a first butt joint hole, a backflow hole, a backflow ring, a flushing hole and a flushing ring; the backflow ring and the guide vane and the primary impeller cooperatively form a backflow cavity; and the flushing ring and the sliding bearing and the sliding bearing sleeve cooperatively form a flushing cavity.

[0008] In some embodiments of the application, the water outlet section is further provided with a second butt joint hole, a pressure relief hole, a pressure relief ring and a balance ring; the balance ring and the balance hub and the final-stage impeller cooperatively form a balance cavity; and the pressure relief ring and the balance hub and the mechanical seal seat cooperatively form a pressure relief cavity.

[0009] In some embodiments of the application, the sliding bearing, the sliding bearing sleeve and the sliding bearing cover cooperatively form a lubricating cavity, and the sliding bearing cover is provided with a backflow groove.

[0010] In some embodiments of the application, the set-type mechanical seal is connected in communication with the lubricating cavity through a flushing lubricating pipe, the balance cavity is connected in communication with the pressure relief cavity through the balance ring, the pressure relief cavity is connected in communication with the backflow cavity through a balance pipe, the pressure relief hole and the backflow hole, the backflow cavity is connected in communication with the flushing cavity through the flushing hole, and the flushing cavity is connected in communication with the lubricating cavity through the backflow groove.

[0011] In some embodiments of the application, an assembly part is further included, which comprises a horizontally arranged bottom plate and a vertical support plate perpendicular to the bottom plate, and the bottom plate and the support plate are both provided with bolts and through holes.

[0012] The embodiment of the application provides a multistage centrifugal pump, which has the following beneficial effects compared with the prior art:

[0013] The embodiment of the present application provides a multistage centrifugal pump, which comprises a water inlet section, a primary impeller, a guide vane, a middle section, a secondary impeller, a final impeller, a water outlet section, a balance hub, a mechanical seal seat, a set type mechanical seal, a pump shaft, a sliding bearing cover, a sliding bearing, a sliding shaft sleeve, a bearing box support, a shaft coupling and a motor, the water inlet section is provided with a water inlet anti-swirl rib, the water outlet section is provided with a water outlet anti-swirl rib, and the middle section is provided with a middle anti-swirl rib; the water inlet anti-swirl rib, the guide vane, the primary impeller and the water inlet section cooperatively form a first anti-swirl front cavity covering the primary impeller, the middle anti-swirl rib, the guide vane, the secondary impeller and the middle section cooperatively form a second anti-swirl front cavity covering the secondary impeller, the middle anti-swirl rib, the final impeller and the water outlet section cooperatively form a third anti-swirl front cavity covering the final impeller, and the water outlet anti-swirl rib cooperatively forms an anti-swirl rear cavity covering the final impeller with the final impeller. Based on the above structure, the multistage centrifugal pump provided by the present application has the first anti-swirl front cavity, the second anti-swirl front cavity, the third anti-swirl front cavity and the anti-swirl rear cavity, the anti-swirl front cavity and the anti-swirl rear cavity can significantly reduce liquid rotation caused by rotation of the impeller, thereby reducing hydraulic loss caused by liquid rotation, improving the efficiency of the water pump, reducing the consumption of the water pump and saving energy; further, the reduction of liquid rotation can also reduce vibration of the water pump, which is beneficial to improving the stability of the water pump and ensuring normal operation of the water pump. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 FIG. 1 is a structural schematic diagram of the multistage centrifugal pump of the embodiment of the present application;

[0015] Figure 2 FIG. 4 is a structural schematic diagram of the water inlet section of the multistage centrifugal pump of the embodiment of the present application;

[0016] Figure 3 FIG. 6 is a structural schematic diagram of the water outlet section of the multistage centrifugal pump of the embodiment of the present application;

[0017] Figure 4 FIG. 8 is a structural schematic diagram of the middle section of the multistage centrifugal pump of the embodiment of the present application;

[0018] Figure 5 FIG. 11 is a structural schematic diagram of the reinforced assembly of the embodiment of the present application.

[0019] In the diagram, 1. Inlet section; 2. First-stage impeller; 3. Guide vane; 4. Middle section; 5. Second-stage impeller; 6. Last-stage impeller; 7. Outlet section; 8. Inlet anti-swirling rib; 9. Outlet anti-swirling rib; 10. Middle anti-swirling rib; 11. First anti-swirling front chamber; 12. Second anti-swirling front chamber; 13. Third anti-swirling front chamber; 14. Anti-swirling rear chamber; 15. Balance hub; 16. Mechanical seal seat; 17. Container-type mechanical seal; 18. Shaft sleeve; 19. Bearing end cover; 20. Bearing; 21. Bushing; 22. Round nut; 23. Pump coupling; 24. Motor; 25. Electrical coupling; 26. Bearing housing bracket; 27. Bearing gland. 28. Washer; 29. ​​Return chamber; 30. Balance pipe; 31. Flushing and lubrication pipe; 32. Balance chamber; 33. Pressure relief chamber; 34. Flushing chamber; 35. Sliding bushing; 36. Pump shaft; 37. Sliding bearing; 38. Snap ring; 39. Lubrication chamber; 40. Sliding bearing cover; 41. Return groove; 42. Tie rod; 43. First mating hole; 44. Return hole; 45. Return ring; 46. Flushing hole; 47. Flushing ring; 48. Second mating hole; 49. Pressure relief hole; 50. Pressure relief ring; 51. Balance ring; 52. Base plate; 53. Support plate; 54. Through hole; 55. Bolt. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] It should be understood that the terms "before," "after," etc., are used in this invention to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, "before" information can also be called "after" information, and "after" information can also be called "before" information, without departing from the scope of this invention.

[0022] like Figures 1 to 5 As shown in the figure, this embodiment of the invention provides a multi-stage centrifugal pump, which includes an inlet section 1, a first-stage impeller 2, a guide vane 3, a middle section 4, a second-stage impeller 5, a final-stage impeller 6, an outlet section 7, a balance hub 15, a mechanical seal seat 16, a cartridge mechanical seal 17, a pump shaft 36, a sliding bearing cover 40, a sliding bearing 37, a sliding shaft sleeve 35, a bearing housing bracket 26, a coupling, and a motor 24. The inlet section 1 is provided with an inlet anti-vortex rib 8, the outlet section 7 is provided with an outlet anti-vortex rib 9, and the middle section 4 is provided with a middle anti-vortex rib. The inlet anti-swirl rib 10, together with the guide vane 3, the first-stage impeller 2 and the inlet section 1, forms the first anti-swirl front cavity 11 covering the first-stage impeller 2. The middle anti-swirl rib 10, together with the guide vane 3, the second-stage impeller 5 and the middle section 4, forms the second anti-swirl front cavity 12 covering the second-stage impeller 5. The middle anti-swirl rib 10, together with the last-stage impeller 6 and the outlet section 7, forms the third anti-swirl front cavity 13 covering the last-stage impeller 6. The outlet anti-swirl rib 9, together with the last-stage impeller 6, forms the anti-swirl rear cavity 14 covering the last-stage impeller 6.

[0023] Based on the above structure, the multi-stage centrifugal pump provided by the application has a first anti-rotation front cavity 11, a second anti-rotation front cavity 12, a third anti-rotation front cavity 13 and an anti-rotation rear cavity 14. The arrangement of the anti-rotation front cavity and the anti-rotation rear cavity can significantly reduce the liquid rotation caused by the rotation of the impeller, thereby reducing the hydraulic loss caused by the liquid rotation, improving the efficiency of the water pump, reducing the consumption of the water pump and saving energy. Further, the reduction of the liquid rotation can also reduce the vibration of the water pump, which is conducive to improving the stability of the water pump and ensuring the normal operation of the water pump.

[0024] Further, as shown in Figure 2 In some embodiments of the application, the water inlet section 1 is further provided with a first docking hole 43, a backflow hole 44, a backflow ring 45, a flushing hole 46 and a flushing ring 47. The backflow ring 45 cooperates with the guide vane 3 and the primary impeller 2 to form a backflow cavity 29, and the flushing ring 47 cooperates with the sliding bearing 37 and the sliding shaft sleeve 35 to form a flushing cavity 34. Figure 3 As shown in Figure 1 The sliding bearing 37 cooperates with the sliding shaft sleeve 35 and the sliding bearing cover 40 to form a lubricating cavity 39, and the sliding bearing cover 40 is provided with a backflow groove 41.

[0025] As shown in Figure 1 The sliding bearing 37 is installed in the sliding bearing cover 40, the circular nut 22 is screwed on the pump shaft 36, the sliding shaft sleeve 35 is sleeved on the pump shaft 36, the snap ring 38 is clamped on the pump shaft 36 and cooperates with the sliding shaft sleeve 35, the circular nut 22 is screwed towards the sliding shaft sleeve 35 and locked and fixed, the sliding bearing cover 40 is installed on the water inlet section 1 after cooperating with the flushing ring 47, the water inlet section 1 is installed and fixed on the bottom plate 52, the sliding shaft sleeve 35 cooperates with the sliding bearing 37 after the pump shaft 36 passes through the water inlet section 1, the primary impeller 2 cooperates with the circular nut 22 and the water inlet section 1 after passing through the pump shaft 36, the guide vane 3 cooperates with the primary impeller 2 and the water inlet section 1 after passing through the pump shaft 36, the middle section 4 cooperates with the guide vane 3 and the water inlet section 1 after passing through the pump shaft 36, the secondary impeller 5 cooperates with the primary impeller 2, the guide vane 3 and the middle section 4 after passing through the pump shaft 36, the guide vane 3 cooperates with the secondary impeller 5 and the middle section 4 after passing through the pump shaft 36, the middle section 4 cooperates with the guide vane 3 and the middle section 4 after passing through the pump shaft 36, the final impeller 6 cooperates with the secondary impeller 5, the guide vane 3 and the middle section 4 after passing through the pump shaft 36, the balance hub 15 cooperates with the final impeller 6 after passing through the pump shaft 36, the balance ring 51 cooperates with the balance hub 15 after the water outlet section 7 passes through the pump shaft 36, and the final impeller 6 and the middle section 4, and the water inlet section 1, the middle section 4, the water outlet section 7 and the guide vane 3 are locked and fixed together by the pull rod 42.

[0026] As Figure 1 shown, the gasket 28 is matched with the balance hub 15 through the pump shaft 36, the mechanical seal seat 16 is installed on the water outlet section 7, the assembled mechanical seal 17 is matched with the mechanical seal seat 16 through the pump shaft 36, the shaft sleeve 18 is matched with the assembled mechanical seal 17 through the pump shaft 36, the bearing end cover 19 is fixedly installed on the bearing box support 26, the bearing box support 26 is installed and fixed on the water outlet section 7 after the bearing end cover 19 is matched with the shaft sleeve 18 and the mechanical seal seat 16 through the pump shaft 36; the bearing 20 is installed on the bushing 21, the bushing 21 is matched with the shaft sleeve 18 through the pump shaft 36, and the bearing 20 is matched with the bearing box support 26 and the bearing end cover 19 at the same time, the round nut 22 is matched with the bushing 21 through the pump shaft 36, and rotating the round nut 22 makes the bushing 21, the shaft sleeve 18, the assembled mechanical seal 17, the gasket 28, the balance hub 15, the last-stage impeller 6, the second-stage impeller 5, the first-stage impeller 2 and the round nut 22 locked and fixed together.

[0027] The assembled mechanical seal 17 is fixed on the mechanical seal seat 16, the bearing pressure cover 27 is locked and fixed after being matched with the bearing 20 and the bearing box support 26 through the pump shaft 36, and the pump joint 23 is installed on the pump shaft 36.

[0028] Further, the balance pipe 30 is installed on the water outlet section 7 and the water inlet section 1, the flushing lubrication pipe 31 is installed on the assembled mechanical seal 17 and the sliding bearing cover 40, the electric joint 25 is installed on the motor 24, the motor 24 is matched with the bearing box support 26, the electric joint 25 is matched with the pump joint 23 after the motor 24 is matched with the bearing box support 26, and the bearing box support 26 is fixed on the bearing box support 26 to form the multi-stage centrifugal pump of the application.

[0029] The assembled mechanical seal 17 is connected with the lubrication cavity 39 through the flushing lubrication pipe 31, the balance cavity 32 is connected with the pressure relief cavity 33 through the balance ring 51, the pressure relief cavity 33 is connected with the backflow cavity 29 through the pressure relief hole 49, the balance pipe 30 and the backflow hole 44, the backflow cavity 29 is connected with the flushing cavity 34 through the flushing hole 46, and the flushing cavity 34 is connected with the lubrication cavity 39 through the backflow groove 41.

[0030] Based on the above structure, the set type mechanical seal 17 is communicated with the lubricating cavity 39, so that the high-pressure liquid at the mechanical seal end flows into the lubricating cavity 39 to fully lubricate the sliding bearing 37. After the return flow cavity 29 is communicated with the flushing cavity 34 and then communicated with the lubricating cavity 39, the high-pressure liquid flows into the lubricating cavity 39 to fully flush and lubricate the sliding bearing 37, thereby prolonging the service life of the pump and reducing the use cost. After the balance cavity 32 is communicated with the pressure relief cavity 33 and then communicated with the return flow cavity 29, the high-pressure liquid flows into the return flow cavity 29, and the rotor of the pump is lifted upward by the front cover plate of the primary impeller 2, so that the high-pressure liquid flows into the guide vane 3 for reuse. The reuse of the liquid saves the work of the motor 24 and improves the efficiency of the pump. The balance cavity 32 balances the axial force of the pump with the balance hub 15, the high-pressure liquid return makes the rotor of the pump lift upward to balance the axial force of the pump again, thereby improving the operation safety and reliability of the water pump, prolonging the service life of the pump, and reducing the operation, maintenance and repair costs of the pump.

[0031] It should be noted that the multi-stage centrifugal pump of the present application needs to be installed on the pump base through the assembly before use to ensure the normal operation of the multi-stage centrifugal pump. Specifically, in some embodiments of the present application, the assembly includes a horizontally arranged bottom plate 52, the bottom plate 52 is provided with a through hole 54 and a bolt 55, the bolt 55 passes through the first butt joint hole 43 to realize the fixed connection of the water pump body and the bottom plate 52, and the bottom plate 52 is fixedly connected with the pump base through the through hole 54, that is, the multi-stage centrifugal pump of the present application is fixed on the pump base through the bottom plate 52 and the bolt 55. Of course, for some special working conditions such as the surface of a ship, the vibration value of the water pump needs to be further limited, at this time, in order to reduce the vibration of the water pump, the assembly further includes a support plate 53 perpendicular to the bottom plate 52, the support plate 53 is also provided with a through hole 54 and a bolt 55, the bolt 55 passes through the second butt joint hole 48 to realize the fixed connection of the water pump body and the support plate 53, and the support plate 53 is also fixedly connected with the pump base through the through hole 54, that is, at this time, the multi-stage centrifugal pump is fixed on the pump base through the bottom plate 52, the support plate 53 and the bolt 55. In this way, the reinforced assembly with the support plate 53 can meet the installation requirements of the multi-stage centrifugal pump in special application occasions, and the running vibration value of the multi-stage centrifugal pump after installation is small, the assembly formed by the bottom plate 52 and the support plate 53 improves the operation safety and reliability of the pump, and reduces the operation, maintenance and repair costs of the pump.

[0032] In summary, the application provides a multi-stage centrifugal pump, comprising a water inlet section, a primary impeller, a guide vane, a middle section, a secondary impeller, a final-stage impeller, a water outlet section, a balance hub, a mechanical seal seat, a set-type mechanical seal, a pump shaft, a sliding bearing cover, a sliding bearing, a sliding bearing sleeve, a bearing box support, a coupling and a motor, the water inlet section is provided with a water inlet anti-swirl rib, the water outlet section is provided with a water outlet anti-swirl rib, and the middle section is provided with a middle anti-swirl rib, the water inlet anti-swirl rib, the guide vane, the primary impeller and the water inlet section cooperate to form a first anti-swirl front cavity covering the primary impeller, the middle anti-swirl rib, the guide vane, the secondary impeller and the middle section cooperate to form a second anti-swirl front cavity covering the secondary impeller, the middle anti-swirl rib, the final-stage impeller and the water outlet section cooperate to form a third anti-swirl front cavity covering the final-stage impeller, and the water outlet anti-swirl rib and the final-stage impeller cooperate to form an anti-swirl rear cavity covering the final-stage impeller. Compared with the prior art, the multi-stage centrifugal pump has a first anti-swirl front cavity, a second anti-swirl front cavity, a third anti-swirl front cavity and an anti-swirl rear cavity, the anti-swirl front cavities and the anti-swirl rear cavity can significantly reduce the liquid rotation driven by the rotation of the impeller, thereby reducing the hydraulic loss caused by the liquid rotation, improving the efficiency of the water pump, reducing the consumption of the water pump and saving energy; further, the reduction of the liquid rotation can also reduce the vibration of the water pump, which is conducive to improving the stability of the water pump and ensuring the normal operation of the water pump.

[0033] The above only describes the preferred embodiments of the application, and it should be noted that those skilled in the art can make several improvements and replacements without departing from the technical principles of the application, and these improvements and replacements should also be considered as the protection scope of the application.

Claims

1. A multi-stage centrifugal pump, characterized by, The pump comprises a water inlet section, a first-stage impeller, a guide vane, a middle section, a second-stage impeller, a last-stage impeller, a water outlet section, a balance hub, a mechanical seal seat, a set mechanical seal, a pump shaft, a sliding bearing cover, a sliding bearing, a sliding bearing sleeve, a bearing box support, a coupling and a motor.

2. The multi-stage centrifugal pump of claim 1, wherein, The water inlet section is provided with a water inlet anti-swirl rib, the water outlet section is provided with a water outlet anti-swirl rib, and the middle section is provided with a middle anti-swirl rib. The water inlet anti-swirl rib, the guide vane, the first-stage impeller and the water inlet section cooperate to form a first anti-swirl front cavity covering the first-stage impeller. The middle anti-swirl rib, the guide vane, the second-stage impeller and the middle section cooperate to form a second anti-swirl front cavity covering the second-stage impeller. The middle anti-swirl rib, the last-stage impeller and the water outlet section cooperate to form an anti-swirl rear cavity covering the last-stage impeller. The water inlet section is further provided with a first butt joint hole, a backflow hole, a backflow ring, a flushing hole and a flushing ring. The backflow ring, the guide vane and the first-stage impeller cooperate to form a backflow cavity. The flushing ring, the sliding bearing and the sliding bearing sleeve cooperate to form a flushing cavity. The water outlet section is further provided with a second butt joint hole, a pressure relief hole, a pressure relief ring and a balance ring. The balance ring, the balance hub and the last-stage impeller cooperate to form a balance cavity. The pressure relief ring, the balance hub and the mechanical seal seat cooperate to form a pressure relief cavity. The sliding bearing, the sliding bearing sleeve and the sliding bearing cover cooperate to form a lubricating cavity. The set mechanical seal is connected to the lubricating cavity through a flushing lubricating pipe. The balance cavity is connected to the pressure relief cavity through the balance ring. The pressure relief cavity is connected to the backflow cavity through a balance pipe, the pressure relief hole and the backflow hole. The backflow cavity is connected to the flushing cavity through the flushing hole. The flushing cavity is connected to the lubricating cavity through the backflow groove. The assembly comprises a horizontally arranged bottom plate and a vertical support plate. The bottom plate and the support plate are provided with bolts and through holes.

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