A low-vibration centrifugal pump

Abstract

This invention provides a low-vibration centrifugal pump. A main impeller is installed inside the pump casing. At least one set of dynamic and static ring assemblies is provided in the gaps between the front and rear cover plates of the main impeller and the pump casing. Each dynamic and static ring assembly has gaps, forming a water film at the gaps to reduce vibration. The dynamic and static ring assembly includes a sealing ring and a balancing ring. One end of the sealing ring is mounted on the pump casing; one end of the balancing ring is mounted on the front / rear cover plate of the main impeller; and one end of the other sealing ring is installed inside the other end of the balancing ring, with a gap between the two sealing rings. This invention can effectively balance the pressure on both sides of the impeller during rotation, thereby greatly reducing the vibration of the main impeller caused by axial force imbalance.

Description

Technical Field

[0001] This invention relates to the field of centrifugal pumps, and particularly to a low-vibration centrifugal pump. Background Technology

[0002] Centrifugal pumps operate by using the centrifugal motion of an impeller to move water. Before starting the pump, the pump casing and suction pipe must be filled with water. Then, the motor is started, causing the pump shaft to drive the impeller and water to rotate at high speed. The water undergoes centrifugal motion, being thrown towards the outer edge of the impeller and flowing into the pump's discharge pipe through the flow channel of the volute casing. Its working medium is mainly water, oil, acid and alkali solutions, emulsions, etc.

[0003] A centrifugal pump's basic structure consists of six parts: impeller, pump body, pump shaft, bearings, and stuffing box. The impeller is the core component of the centrifugal pump, operating at high speeds and producing high output. The inner and outer surfaces of the impeller must be smooth to reduce frictional losses in the water flow. The pump body, also called the pump casing, is the main body of the pump, providing support and stability, and connecting to the bearing mounting bracket. The pump shaft connects to the motor via a coupling, transmitting the motor's torque to the impeller; therefore, it is the primary component for transmitting mechanical energy. The sliding bearings use transparent oil as a lubricant; the oil level must be filled to the mark. Too much oil will seep out along the pump shaft, while too little will cause the bearing to overheat and burn out, leading to an accident. The stuffing box mainly consists of packing, water seal rings, packing sleeves, packing glands, and water seal pipes. The main function of the stuffing box is to seal the gap between the pump casing and the pump shaft, preventing water from flowing out of the pump and preventing outside air from entering the pump.

[0004] When a centrifugal pump operates at high speed, two main issues arise: firstly, a low-pressure zone appears inside the impeller flow channel, leading to cavitation. This not only affects the pump's hydraulic performance but also causes impeller vibration and noise. Secondly, uneven stress on the impeller's front and rear end covers causes dynamic imbalance in the impeller rotor, resulting in impeller vibration. The higher the centrifugal pump's speed and the greater the density of the medium, the more severe the vibration and the less stable the pump's operation. Therefore, it is necessary to control the vibration and cavitation of centrifugal pumps to improve their operational stability and hydraulic performance.

[0005] Traditional centrifugal pumps primarily employ two principles to reduce vibration: firstly, by adding a vibration damping structure; however, this method does not address the root cause of centrifugal pump vibration. Secondly, by using a filter to reduce impurities in the water, thereby reducing impeller vibration. This method is only suitable for applications with a small amount of impurities in the water; when the water being pumped contains a large amount of impurities, it can cause blockage at the pump inlet. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a low-vibration centrifugal pump that can effectively balance the pressure on both sides of the impeller during rotation, thereby greatly reducing the vibration of the main impeller caused by axial force imbalance.

[0007] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0008] A low-vibration centrifugal pump is provided, wherein a main impeller is installed inside the pump casing, and at least one set of dynamic and static ring assemblies are provided in the gaps between the front cover plate and the rear cover plate of the main impeller and the pump casing; each dynamic and static ring assembly is provided with a gap, and a water film is formed in the gap to reduce vibration.

[0009] Furthermore, the dynamic and static ring assembly includes a sealing ring and a balance ring. One end of the sealing ring is mounted on the pump casing; one end of the balance ring is mounted on the front / rear cover plate of the main impeller; one end of the other sealing ring is mounted inside the other end of the balance ring, and a gap is provided between the two sealing rings.

[0010] Furthermore, the pump casing is provided with an annular groove, the other end of the balance ring is located in the annular groove, and the gap between the two sealing rings is located in the annular groove.

[0011] Furthermore, one of the sealing rings is mounted on the pump housing via a connecting sleeve, and the other sealing ring is mounted inside the other end of the balance ring via a connecting sleeve.

[0012] Furthermore, the dynamic and static ring assembly includes a front dynamic and static ring assembly and a rear dynamic and static ring assembly. A plurality of front dynamic and static ring assemblies are evenly distributed radially along the main impeller in the gap between the front cover plate of the main impeller and the pump casing; and a plurality of rear dynamic and static ring assemblies are evenly distributed radially along the main impeller in the gap between the rear cover plate of the main impeller and the pump casing.

[0013] Furthermore, the front dynamic and static ring assembly and the rear dynamic and static ring assembly are located on the same axial direction, or the front dynamic and static ring assembly and the rear dynamic and static ring assembly are staggered.

[0014] Furthermore, the gaps between the front moving and stationary ring assemblies and the gaps between the rear moving and stationary ring assemblies decrease as the diameter of the main impeller increases.

[0015] Furthermore, an auxiliary impeller is installed at the front end of the pump shaft on which the main impeller is installed, and a first chamber is provided between the rear cover plate of the main impeller and the pump cover; a through hole communicating with the first chamber is provided inside the pump shaft; one end of the through hole is connected to the water inlet of the auxiliary impeller; the other end of the through hole is connected to the pumping system outside the pump casing, which is used to generate pressure to balance the axial force of the main impeller.

[0016] Furthermore, the auxiliary impeller has blades rotating in the same direction as the main impeller, and the outlet of the auxiliary impeller is directly opposite the low-pressure area at the root of the main impeller blades.

[0017] Furthermore, the pump casing is provided with a second chamber, and the other end of the through hole is connected to the second chamber; the second chamber is connected to the pumping system for conveying clean water.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. The low-vibration centrifugal pump of the present invention has at least one set of dynamic and static ring assemblies in the gap between the front cover plate and the rear cover plate of the main impeller and the pump casing respectively; the dynamic and static ring assemblies are provided with gaps, and by forming a water film in the gaps, the pressure on both sides of the impeller during rotation can be effectively balanced, thereby greatly reducing the vibration of the main impeller caused by axial force imbalance.

[0020] 2. In the low-vibration centrifugal pump of the present invention, the gap between the two sealing rings is located in the annular groove. Thus, the water film formed at the gap is located in the annular groove. The axial force imbalance of the main impeller will cause the water film to vibrate. The water film can be regarded as an elastic damping, which can reduce some of the vibration. In addition, the vibration generated by the water film will collide and rebound on the wall of the annular groove, which will further reduce the vibration generated by the water film.

[0021] 3. In the low-vibration centrifugal pump of the present invention, the sealing ring is installed on the pump casing through a connecting sleeve, which can reduce the transmission of vibration from the sealing ring to the pump casing.

[0022] 4. In the low-vibration centrifugal pump of the present invention, the gaps between the plurality of front dynamic and static ring assemblies and the gaps between the plurality of rear dynamic and static ring assemblies decrease as the impeller diameter increases, and different gaps are set according to the different pressure distribution and vibration magnitude of the main impeller.

[0023] 5. The low-vibration centrifugal pump of the present invention, wherein clean water injected from the outside is diverted to the first chamber through the pump shaft, and when the clean water fills the chamber, on the one hand, a certain pressure is generated to balance the axial force of the main impeller at this position, thereby improving the running stability of the main impeller; on the other hand, it reduces the flow leakage of the rear port ring of the main impeller, thereby improving the performance of the centrifugal pump.

[0024] 6. The low-vibration centrifugal pump of the present invention has a first chamber between the rear cover plate of the main impeller and the pump cover; a through hole communicating with the first chamber is provided in the pump shaft; one end of the through hole is connected to the water inlet of the auxiliary impeller; the other end of the through hole is connected to the pumping system outside the pump casing, so that the externally injected clean water is injected at a certain pressure and shot through the auxiliary impeller to the root of the blades of the main impeller, so as to compensate for the pressure reduction at the root of the blades caused by the centrifugal force during the operation of the main impeller, thereby reducing the cavitation phenomenon of the impeller, and thus reducing the vibration of the impeller and increasing the service life of the impeller.

[0025] 6. In the low-vibration centrifugal pump of the present invention, the externally injected clean water will diffuse through the outlet of the auxiliary impeller, changing the direction and angle of the outlet of the auxiliary impeller so that the diffusion area can cover the cavitation area of ​​the impeller. The cavitation area can be the working surface or the cavitation area on the back of the blade. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the low-vibration centrifugal pump structure described in this invention.

[0028] Figure 2 for Figure 1 A magnified view of part I.

[0029] Figure 3 for Figure 1 Part II enlarged view.

[0030] Figure 4 This is a schematic diagram of the pump shaft and bushing structure of the low-vibration centrifugal pump described in this invention.

[0031] Figure 5 This is a schematic diagram of the main impeller front cover plate structure of the low-vibration centrifugal pump described in this invention.

[0032] Figure 6 This is a schematic diagram of the main impeller rear cover plate structure of the low-vibration centrifugal pump described in this invention.

[0033] Figure 7 This is a schematic diagram showing the length of the gap described in this invention.

[0034] In the picture:

[0035] 1-Main impeller; 2-Auxiliary impeller; 3-Vortex casing; 4-Pump cover; 5-Bushing; 6-Pump shaft; 7-First sealing ring; 8-Second sealing ring; 9-Third sealing ring; 10-First rubber connecting sleeve; 11-Second rubber connecting sleeve; 12-Third rubber connecting sleeve; 13-First front balance ring; 14-Second front balance ring; 15-Third front balance ring; 16-Suspension component; 17-Water guide ring; 18-First chamber; 19-Second chamber; 20-First rear balance ring; 21-Second rear balance ring; 22-Third rear balance ring. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] like Figure 1As shown, the low-vibration centrifugal pump of the present invention includes a pump casing, a main impeller 1, and a suspension component 16. The pump casing includes a volute 3 and a pump cover 4. The suspension component 16 supports a pump shaft 6, and the main impeller 1 is mounted on one end of the pump shaft 6. The main impeller 1 is located inside the pump casing. At least one set of dynamic and static ring assemblies is provided in the gaps between the front and rear cover plates of the main impeller 1 and the pump casing. Each dynamic and static ring assembly has gaps. By forming a water film in the gaps, the pressure on both sides of the main impeller 1 during rotation can be effectively balanced, thereby greatly reducing the vibration of the main impeller 1 caused by axial force imbalance.

[0040] The dynamic and static ring assembly includes a sealing ring and a balance ring. One end of the sealing ring is mounted on the pump casing; one end of the balance ring is mounted on the front or rear cover plate of the main impeller 1; one end of the other sealing ring is mounted inside the other end of the balance ring, and a gap is provided between the two sealing rings.

[0041] Implementation, for example Figure 1 and Figure 2As shown, the dynamic and static ring assembly includes a front dynamic and static ring assembly and a rear dynamic and static ring assembly. Three front dynamic and static ring assemblies are evenly distributed radially along the main impeller 1 in the gap between the front cover plate and the pump casing of the main impeller 1. The three front dynamic and static ring assemblies are a first front dynamic and static ring assembly, a second front dynamic and static ring assembly, and a third front dynamic and static ring assembly. The third front dynamic and static ring assembly, the second front dynamic and static ring assembly, and the first front dynamic and static ring assembly are radially distributed on the front cover plate of the main impeller 1. The first front dynamic and static ring assembly includes a first sealing ring 7 and a first front balancing ring 13. One end of the first sealing ring 7 is mounted on the volute 3 through a first rubber connecting sleeve 10, which is the static ring. One end of the first front balancing ring 13 is mounted on the front cover plate of the main impeller 1. The other first sealing ring 7 is mounted inside the other end of the first front balancing ring 13 through a first rubber connecting sleeve 10, which is the dynamic ring. The two first sealing rings 7 are axially aligned, and there is a gap between the two first sealing rings 7. The second front dynamic and static ring assembly includes a second sealing ring 8 and a second front balancing ring 14. One end of the second sealing ring 8 is mounted on the volute 3 via a second rubber connecting sleeve 11, which is the static ring. One end of the second front balancing ring 14 is mounted on the front cover plate of the main impeller 1. The other second sealing ring 8 is mounted inside the other end of the second front balancing ring 14 via a second rubber connecting sleeve 11, which is the dynamic ring. The two second sealing rings 8 are axially aligned, and a gap is provided between them. The third front dynamic and static ring assembly includes a third sealing ring 9 and a third front balancing ring 15. One end of the third sealing ring 9 is mounted on the volute 3 via a third rubber connecting sleeve 12, which is the static ring. One end of the third front balancing ring 15 is mounted on the front cover plate of the main impeller 1. The other third sealing ring 9 is mounted inside the other end of the third front balancing ring 15 via a third rubber connecting sleeve 12, which is the dynamic ring. The two third sealing rings 9 are axially aligned, and a gap is provided between them. Figure 1 and Figure 5 As shown, the inner diameter of the first sealing ring 7 is larger than the inner diameter of the second sealing ring 8, and the inner diameter of the second sealing ring 8 is larger than the inner diameter of the third sealing ring 9. For example... Figure 5 As shown, the front cover plate of the main impeller 1 is respectively machined with grooves corresponding to the first front balance ring 13, the second front balance ring 14, and the third front balance ring 15 for the connection of the two.

[0042] Implementation, for example Figure 1 and Figure 3As shown, three rear dynamic and static ring assemblies are evenly distributed radially along the main impeller 1 in the gap between the rear cover plate and the pump casing of the main impeller 1. The three rear dynamic and static ring assemblies are the first rear dynamic and static ring assembly, the second rear dynamic and static ring assembly, and the third rear dynamic and static ring assembly. The third rear dynamic and static ring assembly, the second rear dynamic and static ring assembly, and the first rear dynamic and static ring assembly are radially distributed on the rear cover plate of the main impeller 1. The first rear dynamic and static ring assembly includes a first sealing ring 7 and a first rear balance ring 20. One end of the first sealing ring 7 is mounted on the pump cover 4 through a first rubber connecting sleeve 10. One end of the first rear balance ring 20 is mounted on the rear cover plate of the main impeller 1. One end of the other first sealing ring 7 is mounted inside the other end of the first rear balance ring 20 through a first rubber connecting sleeve 10. The two first sealing rings 7 are axially aligned, and a gap is provided between the two first sealing rings 7. The second rear dynamic and static ring assembly includes a second sealing ring 8 and a second rear balancing ring 21. One end of the second sealing ring 8 is mounted on the pump cover 4 via a second rubber connecting sleeve 11; one end of the second rear balancing ring 21 is mounted on the rear cover plate of the main impeller 1; one end of the other second sealing ring 8 is mounted inside the other end of the second front balancing ring 14 via the second rubber connecting sleeve 11. The two second sealing rings 8 are axially aligned, and a gap is provided between them. The third rear dynamic and static ring assembly includes a third sealing ring 9 and a third rear balancing ring 22. One end of the third sealing ring 9 is mounted on the pump cover 4 via a third rubber connecting sleeve 12; one end of the third rear balancing ring 22 is mounted on the rear cover plate of the main impeller 1; one end of the other third sealing ring 9 is mounted inside the other end of the third rear balancing ring 22 via the third rubber connecting sleeve 12. The two third sealing rings 9 are axially aligned, and a gap is provided between them. Figure 1 and Figure 6 As shown, the inner diameter of the first sealing ring 7 is larger than the inner diameter of the second sealing ring 8, and the inner diameter of the second sealing ring 8 is larger than the inner diameter of the third sealing ring 9. For example... Figure 6 As shown, the rear cover plate of the main impeller 1 is respectively machined with grooves corresponding to the first rear balance ring 20, the second rear balance ring 21, and the third rear balance ring 22 for connection between the two.

[0043] The dynamic and static ring assemblies have similar structures. Taking the first front dynamic and static ring assembly as an example, the volute 3 has an annular groove. One first sealing ring 7 is located in the annular groove, and the other end of the first front balance ring 13 is also located in the annular groove. Since the other first sealing ring 7 is installed at the other end of the first front balance ring 13, the gap between the two first sealing rings 7 is located in the annular groove. Thus, the water film formed at the gap is located in the annular groove. The vibration of the water film caused by the imbalance of the axial force of the main impeller can be regarded as an elastic damping, which can reduce part of the vibration. In addition, the vibration generated by the water film will collide and rebound on the wall of the annular groove, which will further reduce the vibration generated by the water film. Both the front and rear dynamic and static ring assemblies include the annular groove described above.

[0044] An implementation example Figure 1 As shown, the front and rear moving and stationary ring assemblies are located on the same axial direction. In another embodiment, the front and rear moving and stationary ring assemblies are staggered, that is, the front and rear moving and stationary ring assemblies are not located on the same axis, such as the first rear moving and stationary ring assembly being located axially between the first and second front moving and stationary ring assemblies.

[0045] An implementation example Figure 2 and Figure 3 As shown, the size of the gaps between the plurality of front moving and stationary ring assemblies and the size of the gaps between the plurality of rear moving and stationary ring assemblies are the same, meaning that the water films generated between the two sealing rings are theoretically similar. In another embodiment, however, the size of the gaps between the plurality of front moving and stationary ring assemblies and the size of the gaps between the plurality of rear moving and stationary ring assemblies decreases as the diameter of the main impeller 1 increases.

[0046] The size of the gap here can be either the spacing between the gaps or the length of the gap. The spacing between the gaps is the installation distance between the two sealing rings. The length of the gap is as follows: Figure 7 As shown, taking the first front dynamic and static ring assembly as an example, the two first sealing rings 7 are staggered in the axial direction, and the overlapping part of the two first sealing rings 7 in the axial direction is the gap for generating water film, and the length of the overlapping part is the length of the gap.

[0047] like Figure 1 and Figure 4As shown, an auxiliary impeller 2 is installed at the front end of the pump shaft 6 on which the main impeller 1 is mounted. A first chamber 18 is provided between the rear cover plate of the main impeller 1 and the pump cover 4. A through hole communicating with the first chamber 18 is provided inside the pump shaft 6. Three flow channels leading to the shaft through hole are evenly distributed radially on the rear cover plate. One end of the through hole is connected to the water inlet of the auxiliary impeller 4; the other end of the through hole is connected to the pumping system outside the pump casing, used to generate pressure to balance the axial force of the main impeller 1. The blades of the auxiliary impeller 2 have the same rotation direction as those of the main impeller 1, and the water outlet of the auxiliary impeller 2 is directly opposite the low-pressure area at the root of the blades of the main impeller 1. Clean water injected from the outside is diverted to the first chamber 18 through the pump shaft 6. When the clean water fills this chamber, it will, on the one hand, block the slight leakage of the impeller inlet ring to prevent water with particulate impurities from entering the packing seal and causing wear; on the other hand, it will generate a certain pressure to balance the axial force of the main impeller 1 and reduce vibration.

[0048] The groove on the back of the pump cover 4 and the suspension component 16 form a closed second chamber 19. The groove on the back of the pump cover 4 can utilize the weight-reducing groove or weight-reducing hole on the back of the original pump cover 4, or it can utilize the reinforcing rib on the back of the original pump cover 4. Three radially distributed flow channel holes are machined on the near-axial side of the groove, allowing externally injected clean water to flow through the holes on the water guide ring 17 to the through hole of the pump shaft 6, i.e., the other end of the through hole is connected to the second chamber 19; the second chamber 19 is connected to the pumping system for conveying clean water through the water injection hole. Figure 1 As shown, the bushing 5 has three radially distributed flow channel holes machined at corresponding positions on the water guide ring 17, which are used for the flow of clean water to the pump shaft 6. The pump shaft 6 is also machined with three radially distributed flow channel holes at the connection position with the water guide ring 17 and at the position with the rear cover plate of the main impeller 1.

[0049] The working principle is as follows:

[0050] When the centrifugal pump is operating, the pumping system continuously injects water at a certain pressure into the pump body. The centrifugal force of the auxiliary impeller 2 propels the external water at a certain pressure towards the low-pressure area at the root of the blades of the main impeller 1, reducing cavitation and thus reducing pump vibration. Front and rear dynamic and static ring assemblies are installed on the front and rear cover plates of the main impeller 1. During pump operation, a water film at a certain pressure forms in the gaps, balancing the axial force on the front and rear cover plates of the main impeller 1 to some extent, further reducing pump vibration. This invention significantly improves pump vibration and enhances centrifugal pump stability.

[0051] Externally injected clean water diffuses through the outlet of auxiliary impeller 2. By changing the direction and angle of the auxiliary impeller outlet, the diffusion area can cover the cavitation-prone areas of the impeller. These cavitation areas can be the working surface or the back surface of the blades. Changing the direction and angle of the auxiliary impeller outlet means that installing auxiliary impellers with different outlet directions and angles can create diffusion areas of different sizes.

[0052] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0053] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-vibration centrifugal pump, wherein a main impeller (1) is installed inside the pump casing, characterized in that, At least one set of dynamic and static ring assemblies is provided in the gap between the front cover plate and the rear cover plate of the main impeller (1) and the pump casing; each of the dynamic and static ring assemblies is provided with a gap, and a water film is formed in the gap to reduce vibration; The dynamic and static ring assembly includes a sealing ring and a balance ring. One end of the sealing ring is mounted on the pump casing; one end of the balance ring is mounted on the front / rear cover plate of the main impeller (1); one end of the other sealing ring is mounted inside the other end of the balance ring, and a gap is provided between the two sealing rings. The moving and stationary ring assembly includes a front moving and stationary ring assembly and a rear moving and stationary ring assembly. A plurality of front moving and stationary ring assemblies are evenly distributed radially along the main impeller (1) in the gap between the front cover plate of the main impeller (1) and the pump casing. A plurality of rear moving and stationary ring assemblies are evenly distributed radially along the main impeller (1) in the gap between the rear cover plate of the main impeller (1) and the pump casing. The front moving and stationary ring assemblies and the rear moving and stationary ring assemblies are located in the same axial direction, or the front moving and stationary ring assemblies and the rear moving and stationary ring assemblies are staggered. The gaps between the plurality of front moving and stationary ring assemblies and the gaps between the plurality of rear moving and stationary ring assemblies decrease as the diameter of the main impeller (1) increases. The pump casing is provided with an annular groove, one of the sealing rings is installed in the annular groove, the other end of the balance ring is located in the annular groove, and the gap between the two sealing rings is located in the annular groove.

2. The low-vibration centrifugal pump according to claim 1, characterized in that, One of the sealing rings is mounted on the pump housing via a connecting sleeve, and the other sealing ring is mounted inside the other end of the balance ring via a connecting sleeve.

3. The low-vibration centrifugal pump according to any one of claims 1-2, characterized in that, An auxiliary impeller (2) is installed at the front end of the pump shaft (6) on which the main impeller (1) is installed. A first chamber (18) is provided between the rear cover plate of the main impeller (1) and the pump cover (4). A through hole communicating with the first chamber (18) is provided inside the pump shaft (6). One end of the through hole is connected to the water inlet of the auxiliary impeller (2). The other end of the through hole is connected to the pumping system outside the pump casing to generate pressure to balance the axial force of the main impeller (1).

4. The low-vibration centrifugal pump according to claim 3, characterized in that, The auxiliary impeller (2) has the same blade rotation direction as the main impeller (1), and the outlet of the auxiliary impeller (2) is directly opposite the low-pressure area at the root of the blade of the main impeller (1).

5. The low-vibration centrifugal pump according to claim 3, characterized in that, The pump casing is provided with a second chamber (19), and the other end of the through hole is connected to the second chamber (19); the second chamber (19) is connected to the pumping system for conveying clean water.

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