Self-balancing segmented multistage centrifugal pump

Abstract

The application belongs to the field of centrifugal pumps and discloses a self-balancing sectional multistage centrifugal pump, which comprises a motor, a pump body, a shaft coupling, a front pump shaft, a rear pump shaft, a bearing, a front shell assembly, a rear shell assembly, a long rod clamping bolt, a head vane assembly, a middle vane assembly, a tail vane assembly, a water inlet pipe, a water outlet pipe, a balance pipe, a balance seat and a balance disc. The head vane assembly and the middle vane assembly are single-vane assemblies, and the tail vane assembly is a double-vane assembly and comprises a tail shell and a semi-solid shaft reverse double-vane. A semi-solid shaft turbine is arranged in the interior of the front shell assembly, the shaft end of the semi-solid shaft turbine, the solid shaft single-vane and the shaft end of the semi-solid shaft reverse double-vane are sequentially connected through a plurality of spline hoops in sequence, the front pump shaft is drivingly connected to the semi-solid shaft turbine from front to back, and the rear pump shaft is drivingly connected to the semi-solid shaft reverse double-vane from back to front. The application has the advantages of reasonable design, good self-balancing effect, convenience in disassembly and maintenance and improvement of the actual working efficiency of the system.

Description

Technical Field

[0001] The invention belongs to the field of centrifugal pumps, and in particular relates to a self-balancing segmented multi-stage centrifugal pump. Background Art

[0002] Centrifugal pumps come in a variety of styles, including vertical, horizontal, single-stage, multi-stage, single-suction, double-suction, and self-priming. Centrifugal pumps operate by centrifugally moving water as the impeller rotates. Before starting the pump, the pump casing and suction pipe are filled with water. The motor is then started, causing the pump shaft to rotate the impeller and water at high speed. This centrifugal motion causes the water to be thrown toward the outer edge of the impeller and flow through the flow channel of the volute casing into the pump's pressure water line. Multistage centrifugal pumps have two or more impellers on the pump shaft. Because multistage centrifugal pumps experience 2-5mm of axial drift during operation, some multistage centrifugal pumps use a double-suction design to achieve self-balancing, such as the single-casing, segmented, self-balancing horizontal multistage centrifugal pump disclosed in CN204163994U. Other multistage centrifugal pumps typically incorporate a balancing disc and balancing pipe structure on the tail blade side, such as the novel double-balanced multistage centrifugal pump disclosed in CN115596674A.

[0003] Existing patent CN102913452A is a first-stage symmetrical double-suction segmented multistage centrifugal pump, which includes a pump shaft and several impeller groups fixed on the pump shaft. A pair of impeller groups are symmetrically arranged on both sides of the suction end of the centrifugal pump. The ends of the symmetrically arranged impeller groups are arranged face to face. The impeller groups located at the suction end and the discharge end of the centrifugal pump are evenly arranged in the same direction. The pair of impeller groups symmetrically arranged on both sides of the suction end of the centrifugal pump include a first-stage impeller and a first-stage counter-impeller. The first-stage impeller is equipped with a first-stage guide vane, and the first-stage counter-impeller is equipped with a first-stage counter-guide vane. The axial forces generated by the first-stage impeller and the first-stage counter-impeller are equal in magnitude and opposite in direction. In addition to the design of a balancing disc and a balancing pipe, this multistage centrifugal pump also proposes a design of positive and negative first blades. However, such centrifugal pumps have the following problems in actual operation: first, one interface of the balancing pipe used in conjunction with the balancing disc is connected to the balancing chamber on the same side of the balancing disc, and the other interface is connected to the suction end of the centrifugal pump. The balancing principle of the balancing disc is to achieve balance by the pressure on the impeller side and the balance disc side. 50%-80% of the axial force acts on the balancing seat where the balancing disc is installed. The positive and negative design is adopted in the first blade, and the balancing effect on the axial force generated by the continuous rotation of the subsequent impeller and fluid is not obvious; second, the guide vane in the centrifugal pump is not very stable. The guide vanes in the centrifugal pump are similar and are all arranged at the edge of the impeller where the water flows out. They generally only serve to guide the flow, and the water flows to the back of the impeller by relying on fluid dynamics and inertia to enter the next impeller, causing most of the fluid to participate in the axial force balance process, increasing the instability coefficient. Furthermore, although the front and rear impellers are designed to be installed in sections, the inspection and disassembly process needs to start from the motor and coupling position, and then disassemble them one by one. In addition, the motor and pump body are usually connected to the base of the workshop or pump room, which increases the intensity of disassembly and maintenance. Summary of the Invention

[0004] In response to the technical problems existing in the above-mentioned centrifugal pumps, the present invention proposes a self-balancing segmented multi-stage centrifugal pump which has a reasonable design, good self-balancing effect and is easy to disassemble and repair.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: the present invention provides a self-balancing segmented multi-stage centrifugal pump, including a motor and a pump body, a coupling is provided at the power output end of the motor, a pump shaft connected to the coupling is provided at the center of the pump body, and a plurality of bearings are provided at both ends of the pump shaft, the pump body includes a front shell assembly and a rear shell assembly, the front shell assembly and the rear shell assembly are connected by a plurality of long rod clamping bolts, the front shell assembly and the rear shell assembly are respectively provided with a first blade assembly, a plurality of middle blade assemblies and a tail blade assembly, the first blade assembly and the tail blade assembly are respectively provided with a water inlet and a water outlet, the water inlet is provided with a balancing pipe connected to the rear shell assembly, the interior of the rear shell assembly is a balancing chamber and a balancing seat and a balancing disk are provided in the balancing chamber, the first blade assembly and the middle blade assembly are The single impeller assembly and the single impeller assemblies adjacent to each other in front and behind are nested with each other, the single impeller assembly comprising a pair of half-impeller shells, the center of the half-impeller shells being provided with an impeller mounting hole, the half-impeller shells being provided with guide vanes on the front side of the impeller mounting hole, a solid shaft single impeller being provided in the impeller mounting hole, the tail blade assembly being a double impeller assembly, the double impeller assembly comprising a tail blade shell, a semi-solid shaft reverse double impeller being provided inside the tail blade shell, a semi-solid shaft turbine being provided inside the front shell assembly, the shaft ends of the semi-solid shaft turbine, the solid shaft single impellers adjacent to each other in front and behind, and the shaft ends of the semi-solid shaft reverse double impellers being sequentially connected through a plurality of spline hoops, the pump shaft comprising a front pump shaft and a rear pump shaft, the front pump shaft being connected to the semi-solid shaft turbine from front to rear, and the rear pump shaft being connected to the semi-solid shaft reverse double impeller from rear to front.

[0006] Preferably, the spline hoop includes a pair of half-hoops, a plurality of spline grooves are provided on the inner side of the half-hoops, and a plurality of pairs of countersunk threaded holes are provided on the half-hoops, which are spaced apart from the spline grooves. The shaft end of the semi-solid shaft turbine, the front and rear adjacent solid shaft single impellers and the shaft end of the semi-solid shaft reverse double impeller are all provided with splines for cooperating with the spline grooves, and the splines are provided with threaded blind holes corresponding to the countersunk threaded holes, and the threaded blind holes are connected to the countersunk threaded holes by countersunk bolts.

[0007] Preferably, the half-impeller shell includes an outer shell, a sleeve and a lip are respectively provided at both ends of the outer shell, a partition is provided on the inner side of the outer shell to divide the inner side into two interconnected spaces, the impeller mounting hole is provided in the center of the partition, and a plurality of axial positioning protrusions distributed at intervals are provided on the outer side of the outer shell, a positioning blind hole is provided at one end of the axial positioning protrusion and a positioning pin for cooperating with the positioning blind hole is provided at the other end.

[0008] Preferably, the side of the partition opposite to the guide vane is a stepped structure, and the guide vane includes an annular blade segment corresponding to the plate surface of the partition, and one side of the annular blade segment cooperates with the supporting ring convex support arranged on the back of the solid shaft single impeller. The inner side of the annular blade segment is provided with multiple support segments connected to the partition, and a guide channel for passing fluid is formed between adjacent support segments.

[0009] Preferably, a spacer sleeve is provided between the semi-solid shaft reverse double impeller and the balancing disk, the balancing seat is provided with an axial countersunk groove at one end facing the spacer sleeve, and the end of the balancing disk is provided with a limiting shoulder that cooperates with the axial countersunk groove.

[0010] Preferably, the balancing disk is provided with an annular track on the side facing away from the limiting shoulder, a spring joint is provided in the track, the spring joint is provided at one end of the spiral spring, the spiral radius of the spiral spring gradually increases from the spring joint and a plurality of fixing parts are provided on the end circle thereof, the fixing parts are provided on the inner wall of the balancing chamber.

[0011] Preferably, a buffer sealing cavity is provided in the center of the front shell assembly, a baffle connected to the pump shaft is provided inside the buffer sealing cavity, a sealing spring distributed on both sides of the baffle is provided in the buffer sealing cavity, and a sealing flange is provided at the end of the sealing spring.

[0012] Preferably, the shaft end of the semi-solid shaft turbine, the shaft ends of the solid shaft single impellers adjacent to each other and the semi-solid shaft reverse double impellers are all provided with wear-resistant brake pads.

[0013] Preferably, a sealing ring is provided in the impeller mounting hole.

[0014] Preferably, the outer peripheral surface of the spline hoop is provided with bullnose perforations.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are:

[0016] 1. The self-balancing segmented multi-stage centrifugal pump provided by the present invention not only adopts the design of a balancing disc and a balancing pipe to balance the axial flow, but also adopts a double impeller assembly design for the tail vane assembly, thereby balancing part of the axial force generated by the continuous operation of the multi-stage single impeller assembly, thereby improving the self-balancing performance of the equipment.

[0017] 2. The guide vanes of the self-balancing segmented multi-stage centrifugal pump provided by the present invention can not only guide the flow, but also reduce the real-time impact of the fluid pressure on the rear side of the solid shaft single impeller. At the same time, they can also play the role of axial support. While reducing unstable factors, it plays the role of balancing the axial force, which can improve the self-balancing performance of the equipment to a certain extent.

[0018] 3. The self-balancing segmented multi-stage centrifugal pump provided by the present invention divides the pump shaft into two and establishes a transmission relationship with the semi-solid shaft turbine, the solid shaft single impeller and the semi-solid shaft reverse double impeller. On the one hand, it realizes effective power transmission, and on the other hand, it can disassemble the equipment by means of intermediate disassembly, which is conducive to reducing the workload of disassembly and maintenance. The design is reasonable and conducive to improving the actual working efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0020] Figure 1 A perspective view of a self-balancing segmented multi-stage centrifugal pump provided in an embodiment;

[0021] Figure 2 A front view of a self-balancing segmented multi-stage centrifugal pump provided in an embodiment;

[0022] Figure 3 A left side view of a self-balancing segmented multi-stage centrifugal pump provided in an embodiment;

[0023] Figure 4 for Figure 2 Cross-sectional view of the self-balancing segmental multi-stage centrifugal pump in the GG direction;

[0024] Figure 5 for Figure 4 A magnified schematic diagram of the structure A in the middle;

[0025] Figure 6 for Figure 3 Cross-sectional view of the self-balancing segmental multi-stage centrifugal pump (without motor and coupling) in the EE direction;

[0026] Figure 7 for Figure 6 A magnified schematic diagram of structure B in the middle;

[0027] Figure 8 An exploded view of a single impeller assembly and a splined collar provided for an embodiment;

[0028] Figure 9 An axonometric view of a semi-solid shaft reverse dual impeller provided for an embodiment;

[0029] Figure 10 An axonometric view of a semi-solid shaft reverse dual impeller in another direction provided for an embodiment;

[0030] Figure 11An axonometric diagram showing the distribution of the scroll springs provided in the embodiment within the rear housing assembly;

[0031] In the above figures:

[0032] 1. Motor; 2. Coupling; 3. Pump shaft; 31. Front pump shaft; 32. Rear pump shaft; 4. Bearing; 5. Front housing assembly; 51. Buffer seal chamber; 52. Baffle; 53. Sealing spring; 54. Sealing flange; 6. Rear housing assembly; 7. Long rod clamping bolt; 8. Single impeller assembly; 81. Half impeller housing; 811. Outer housing; 812. Socket; 813. Lip; 814. Partition; 815. Axial locating protrusion; 816. Positioning blind hole; 817. Positioning pin; 82. Impeller mounting hole; 83. Guide vane; 831. Ring segment; 832. Support segment; 84. Solid shaft single impeller; 85. Support ring protrusion; 9. Double impeller assembly Parts; 91. Tail blade shell; 92. Semi-solid shaft reverse double impeller; 10. Water inlet pipe; 11. Water outlet pipe; 12. Balance pipe; 13. Balance chamber; 14. Balance seat; 141. Axial countersunk; 15. Balance plate; 151. Limit shoulder; 152. Track; 16. Semi-solid shaft turbine; 17. Spline hoop; 171. Half hoop sleeve; 172. Spline groove; 173. Countersunk threaded hole; 174. Spline; 175. Threaded blind hole; 176. Countersunk bolt; 177. Bullnose perforation; 18. Spacer sleeve; 19. Volute spring; 191. Spring joint; 192. Fixing piece; 20. Wear-resistant brake pad; 21. Sealing ring. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other unless they conflict. For the convenience of description, the words "upper", "lower", "left", and "right" appearing below only indicate the upper, lower, left, and right directions consistent with the drawings themselves and do not limit the structure.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Examples, such as Figures 1-11As shown, the self-balancing segmented multi-stage centrifugal pump provided by the present invention includes a motor 1 and a pump body, a coupling 2 is provided at the power output end of the motor 1, a pump shaft 3 connected to the coupling 2 is provided at the center of the pump body, and a plurality of bearings 4 are provided at both ends of the pump shaft 3. The pump body includes a front shell assembly 5 and a rear shell assembly 6, and the front shell assembly 5 and the rear shell assembly 6 are connected by a plurality of long rod clamping bolts 7. The front shell assembly 5 and the rear shell assembly 6 are sequentially provided with a first blade assembly, a plurality of middle blade assemblies and a tail blade assembly, and the first blade assembly and the tail blade assembly are respectively provided with a water inlet pipe port 10 and a water outlet pipe port 11, and the water inlet pipe port 10 is provided with a balancing pipe 12 connected to the rear shell assembly 6, and the interior of the rear shell assembly 6 is a balancing chamber 13 and a balancing seat 14 and a balancing disk 15 are provided in the balancing chamber 13. Among them, the working space of the front shell assembly 5 and the rear shell assembly 6 maintains a certain sealing basis with the working space of the impeller; the long rod clamping bolt 7 is used to clamp the front shell assembly 5, a tail blade assembly, the first blade assembly and the tail blade assembly and the rear shell assembly 6; there are at least two sets of bearings 4 in the front shell assembly 5 and the rear shell assembly 6, and the pump shaft 3 is concentrically supported by the bearings 4 to provide a stable working axis for the pump shaft 3; the balancing plate 15, the balancing seat 14, the balancing chamber 13 and the balancing pipe 12 constitute a basic channeling balancing mechanism, which is used to balance the front and rear side pressures of all impellers, thereby providing self-balancing protection for the pump shaft 3 and all impellers.

[0036] In order to improve the self-balancing performance of the present invention, the first blade assembly and the middle blade assembly provided by the present invention are both single impeller assemblies 8 and the front and rear adjacent single impeller assemblies 8 are nested with each other. The single impeller assembly 8 includes a pair of half blade shells 81. The center of the half blade shell 81 is provided with an impeller mounting hole 82. The half blade shell 81 is provided with a guide vane 83 on the front side of the impeller mounting hole 82. A solid shaft single impeller 84 is provided in the impeller mounting hole 82. The tail blade assembly is a double impeller assembly 9 and is nested with the single impeller assembly 8 and the rear shell assembly 6 on its rear side. The double impeller assembly 9 includes a tail blade shell 91, the tail blade shell 9 1 is provided with a semi-solid shaft reverse double impeller 92 inside, and a semi-solid shaft turbine 16 is provided inside the front shell assembly 5. The shaft end of the semi-solid shaft turbine 16, the solid shaft single impeller 84 adjacent to the front and rear, and the shaft end of the semi-solid shaft reverse double impeller 92 are sequentially connected through multiple spline hoops 17. The pump shaft 3 includes a front pump shaft 31 and a rear pump shaft 32. The front pump shaft 31 is connected to the semi-solid shaft turbine 16 from front to rear. The semi-solid shaft turbine 16 is used to compress water to flow toward the first blade assembly. The rear pump shaft 32 is connected to the semi-solid shaft reverse double impeller 92 from rear to front.

[0037] Specifically, in addition to adopting the design of the balancing disc 15 and the balancing pipe 12 to balance the axial leakage, the present invention also adopts the design of the double impeller assembly 9 for the tail blade assembly. The semi-solid shaft reverse double impeller 92 is two impellers welded back to back. The flow channel direction inside the impeller is the same, but the direction of the water inlet and outlet is different. In particular, the impeller facing the side of the balancing seat 14 can spit part of the water between the two to the water outlet pipe 11 by rotation, thereby reducing the pressure difference on both sides of the semi-solid shaft reverse double impeller 92, so it can also balance part of the axial force generated by the continuous operation of the multi-stage single impeller assembly 8, thereby improving the self-balancing performance of the equipment. Furthermore, the guide vane 83 designed in the present invention, on the one hand, can improve its guide effect as a guide structure through the extension design on the back of the solid shaft single impeller 84, and cause the structure to divide the fluid on the rear side of the solid shaft single impeller 84 and the occupancy ratio of the structure itself, which can reduce the real-time impact of the fluid pressure on the rear side of the solid shaft single impeller 84. On the other hand, the guide vane 83 can also play the role of axial support, while reducing the instability factors of the fluid, it plays the role of balancing the axial force, further improving the self-balancing performance of the present equipment.

[0038] like Figure 4-Figure 7 As shown, the self-balancing segmented multi-stage centrifugal pump provided by the present invention divides the pump shaft 3 into two, and establishes a transmission relationship with the semi-solid shaft turbine 16, the solid shaft single impeller 84 and the semi-solid shaft reverse double impeller 92, so as to realize effective power transmission on the one hand, and on the other hand, for inspecting the middle part of the pump body, namely the first blade assembly, the middle blade assembly and the tail blade assembly, the long rod clamping bolt 7 can be removed first, and then the half blade shell 81 can be removed, and then the first blade assembly, the middle blade assembly and the tail blade assembly can be disassembled from the middle, which can effectively reduce the workload of disassembly and maintenance, and the design is reasonable and conducive to improving the actual working efficiency of the system.

[0039] like Figure 6 、 Figure 8 and Figure 9As shown, the spline hoop 17 provided by the present invention includes a pair of half-hoops 171, each of which is provided with a plurality of spline grooves 172 on its inner side. The half-hoops 171 are provided with a plurality of pairs of countersunk threaded holes 173 spaced apart from the spline grooves 172. The shaft ends of the semi-solid shaft turbine 16, the adjacent solid shaft single impeller 84, and the semi-solid shaft reverse double impeller 92 are all provided with splines 174 for mating with the spline grooves 172. The splines 174 are provided with threaded blind holes 175 corresponding to the countersunk threaded holes 173. The threaded blind holes 175 and the countersunk threaded holes 173 are connected by countersunk bolts 176. The splines 174 and the spline grooves 172 provide multiple key connection bases, and the half-hoops 171 are buckled onto the connection position of the front and rear solid shafts in a half-sleeve manner. The countersunk bolts 176 serve to fix the spline, thereby ensuring the synchronous transmission relationship between the front and rear solid shafts. At the same time, the half-and-half design of the spline hoop 17 is also to facilitate the reasonable disassembly of the adjacent solid shaft single impeller 84, semi-solid shaft turbine 16, and semi-solid shaft reverse double impeller 92. It should be noted that the diameter of the solid portion of the solid shaft single impeller 84 and the semi-solid shaft reverse double impeller 92 is smaller than the caliber of the impeller inlet, which does not affect the passage of the fluid through the impeller flow channel; the shaft end of the semi-solid shaft turbine 16, the front and rear adjacent solid shaft single impeller 84, and the shaft end of the semi-solid shaft reverse double impeller 92 are designed with splines, and the outermost side of the spline 174 is on the same curved surface as the outermost side of the solid shaft, and the countersunk bolt 176 is also a concealed connection design, so it will not significantly affect the driving effect of the impeller on the fluid.

[0040] like Figure 4 and Figure 8As shown, the half-impeller shell 81 provided by the present invention includes an outer shell 811, and a sleeve 812 and a lip 813 are respectively provided at both ends of the outer shell 811. The inner side of the outer shell 811 is provided with a partition 814 that divides the inner side into two interconnected spaces in front and back. The impeller mounting hole 82 is provided at the center of the partition 814, and the outer side of the outer shell 811 is provided with a plurality of axial positioning protrusions 815 distributed at intervals. One end of the axial positioning protrusion 815 is provided with a positioning blind hole 816 and the other end thereof is provided with a positioning pin 817 for cooperating with the positioning blind hole 816. Specifically, the sleeves 812 and lips 813 of adjacent single impeller assemblies 8 are nested with each other, which not only plays a sealing role, but also plays a docking and centering role; a working chamber for the solid shaft single impeller 84 and the guide vane 83 is formed between the partitions 814 of the adjacent single impeller assemblies 8, and the working chamber is also open to the left and right during the disassembly and assembly process, which can reduce the assembly difficulty of the device; the axial positioning protrusion 815 increases the sealing surface of the front and rear single impeller assemblies 8 on the one hand, and provides a processing surface and a welding surface for the positioning pin 817 and the positioning blind hole 816 on the other hand. The processed positioning pin 817 and positioning blind hole 816 can play a positioning role, especially the shell parts of all the front and rear single impeller assemblies 8 remain relatively fixed in the working state, and the position of the guide vane 83 is also determined after assembly, which is conducive to ensuring the assembly accuracy of the solid shaft single impeller 84 and ensuring the overall driving effect of the guide vane 83 and the solid shaft single impeller 84 on the fluid. Regarding the sealing design of the front and rear single impeller assemblies 8, before assembly is completed, a layer of sealant can be applied on the sleeves 812 and lips 813 of the front and rear half-blade shells 81, and a layer of sealant can be applied on the mating surfaces of the half-blade shells 81 to improve the overall sealing performance of the equipment after assembly.

[0041] like Figure 5 and Figure 8As shown, the side of the partition 814 provided by the present invention opposite the guide vane 83 has a stepped structure. The guide vane 83 includes an annular blade segment 831 corresponding to the plate surface of the partition 814. One side of the annular blade segment 831 is supported and cooperated with the support ring protrusion 85 provided on the back of the solid shaft single impeller 84. The inner side of the annular blade segment 831 is provided with multiple support segments 832 connected to the partition 814. The adjacent support segments 832 form a diversion channel for the passage of fluid. The partition 814 and the guide vane 83 adopt a stepped design, and the diversion channel formed includes a horizontal portion and an inclined portion. The end of the inclined portion faces the water inlet of the solid shaft single impeller 84. The water discharged from the edge of the impeller enters the horizontal portion under the action of kinetic energy and inertia, and then flows along the inclined portion to the water inlet of the solid shaft single impeller 84. In this way, the annular blade segment 831 and the solid shaft single impeller 84 have a certain overlap in the axial direction. Within this overlap, a portion of the fluid pressure acts directly on the half-impeller casing 81, reducing the pressure acting on the back of the solid shaft single impeller 84. Furthermore, two or three supporting annular protrusions 85 can be designed on the back of the solid shaft single impeller 84. While ensuring the fluid path is connected, the annular blade segment 831 can reasonably support the back of the solid shaft single impeller 84, balancing some of the axial thrust, thereby improving the self-balancing performance of the device.

[0042] To improve self-balancing performance, a spacer sleeve 18 is provided between the semi-solid shaft counter-rotating dual impeller 92 and the balancing disc 15. The balancing seat 14 is provided with an axial countersunk notch 141 at one end facing the spacer sleeve 18, and a stop shoulder 151 is provided at the end of the balancing disc 15 to cooperate with the axial countersunk notch. The spacer sleeve 18 serves to space the balancing disc 15 from the semi-solid shaft counter-rotating dual impeller 92 and transmit axial force to the balancing disc 15. The nested design of the axial countersunk notch 141 and the stop shoulder 151 forms a stop mechanism between the balancing disc 15 and the balancing seat 14. This ensures that the balancing chamber 13 and the working chamber of the semi-solid shaft counter-rotating dual impeller 92 are relatively isolated, ensuring that the balancing range of the balancing disc 15 is within a controllable range, which is larger than the original 2-5mm axial drift. This prevents the device from occasionally entering a pressure-suppressed operating condition, thereby ensuring the device's actual operating performance and, to a certain extent, improving the device's actual service life.

[0043] Furthermore, the present invention provides an annular track 152 on the side of the balancing disc 15 facing away from the limiting shoulder. A spring joint 191 is disposed within track 152. Spring joint 191 is positioned at one end of a spiral spring 19. The spiral radius of spiral spring 19 gradually increases from spring joint 191, and multiple fixings 192 are disposed along the distal end of the spiral spring 19. Fixings 192 are located on the inner wall of balancing chamber 13. The inclusion of spiral spring 19 in balancing chamber 13 provides a certain amount of dynamic elastic force to balancing disc 15, particularly during moments of continuous dynamic self-adjustment, thereby improving the self-balancing performance of the device. Among them, the main body of the fixing part 192 is a fixing tube, the side opening of the fixing tube is used to pass the spiral spring 19, and the end of the fixing tube is screwed in and tightened; the spring joint 191 adopts an I-shaped design, and its I-shaped part is slidably set in the track 152, and its end is connected to the spiral spring by using a side opening + end screw method, so when the balancing disc 15 continues to rotate subsequently on the pump shaft 32, the end of the spiral spring can always support the balancing disc 15, and the spiral spring itself does not produce large-scale distortion.

[0044] To improve the relative sealing between the front pump shaft 31 and the front housing assembly 5, the present invention provides a buffer seal chamber 51 at the center of the front housing assembly 5. A baffle 52 connected to the pump shaft 3 is disposed within the buffer seal chamber 51. Sealing springs 53 are disposed within the buffer seal chamber 51 and are distributed on both sides of the baffle 52. Sealing flanges 54 are disposed at the ends of the sealing springs 53. By designing a pair of sealing flanges 54, the working chamber of the first lobe assembly and the inner chamber of the front housing assembly 5 are sealed. Simultaneously, the axial movement of the baffle 52 is synchronized with the axial movement of the front pump shaft 31. While the front pump shaft 31 is in dynamic self-balancing, the sealing springs 53 support the two sealing flanges 54, further ensuring the actual service life of the bearing 4 within the front housing assembly 5.

[0045] In order to improve the water pumping performance of the centrifugal pump, from a transmission perspective, the present invention provides wear-resistant brake pads 20 at the shaft ends of the semi-solid shaft turbine 16, the solid shaft single impeller 84 adjacent to the front and rear, and the semi-solid shaft reverse double impeller 92. The installation of the wear-resistant brake pads 20 increases the friction and tension at the shaft ends of the semi-solid shaft turbine 16, the solid shaft single impeller 84 adjacent to the front and rear, and the semi-solid shaft reverse double impeller 92, thereby improving the synchronous drive performance of the impellers at different positions. Furthermore, the shear load on the countersunk bolts 176 on the spline hoop 17 can be reduced to a certain extent, thereby ensuring the connection reliability of the spline hoop 17 at the shaft end.

[0046] In order to reduce the reverse leakage of water at the installation node of the solid shaft single impeller 84, the present invention provides a sealing ring 21 in the impeller installation hole 82. The sealing ring 21 not only plays the role of sealing the assembly node, but also plays the role of shaft sleeve support based on its smooth surface processing.

[0047] In order to improve the connection reliability of the spline hoop 17 to the shaft end, the spline groove 172 and the spline are designed with an inclined surface. For example, the arc length of the central end of the spline groove 172 is greater than the arc length of the proximal end, and the spline groove 172 and the spline 174 can be nested by press-fitting; in order to reduce the difficulty of disassembling the spline hoop 17, a bull nose through-hole 177 is provided on the outer peripheral surface of the spline hoop 17. After removing the countersunk bolt 176, a special tool is inserted into the bull nose through-hole 177 and hooked outward to remove the half hoop sleeve 171.

[0048] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A self-balancing segmented multi-stage centrifugal pump, comprising a motor and a pump body, a coupling being provided at the power output end of the motor, a pump shaft connected to the coupling being provided at the center of the pump body, a plurality of bearings being provided at both ends of the pump shaft, the pump body comprising a front shell assembly and a rear shell assembly, the front shell assembly and the rear shell assembly being connected by a plurality of long rod clamping bolts, the front shell assembly and the rear shell assembly being provided with a first blade assembly, a plurality of middle blade assemblies and a tail blade assembly in sequence, the first blade assembly and the tail blade assembly being provided with a water inlet and a water outlet respectively, the water inlet being provided with a balancing pipe communicating with the rear shell assembly, the interior of the rear shell assembly being a balancing chamber and a balancing seat and a balancing disk being provided in the balancing chamber, characterized in that The first blade assembly and the middle blade assembly are both single impeller assemblies and the single impeller assemblies adjacent to each other are nested in each other. The single impeller assembly includes a pair of half blade shells, the center of the half blade shell is provided with an impeller mounting hole, the half blade shell is provided with a guide vane on the front side of the impeller mounting hole, and a solid shaft single impeller is provided in the impeller mounting hole. The tail blade assembly is a double impeller assembly, and the double impeller assembly includes a tail blade shell, a semi-solid shaft reverse double impeller is provided inside the tail blade shell, and a semi-solid shaft turbine is provided inside the front shell assembly. The shaft ends of the semi-solid shaft turbine, the solid shaft single impellers adjacent to each other in front and back, and the shaft ends of the semi-solid shaft reverse double impellers are sequentially connected through multiple spline hoops. The pump shaft includes a front pump shaft and a rear pump shaft. The front pump shaft is connected to the semi-solid shaft turbine from front to rear, and the rear pump shaft is connected to the semi-solid shaft reverse double impeller from rear to front.

2. The self-balancing segmented multi-stage centrifugal pump according to claim 1, characterized in that: The spline hoop includes a pair of half-hoop sleeves, a plurality of spline grooves are provided on the inner side of the half-hoop sleeves, and a plurality of pairs of countersunk threaded holes are provided on the half-hoop sleeves and are spaced apart from the spline grooves. The shaft end of the semi-solid shaft turbine, the solid shaft single impeller adjacent to the front and rear, and the shaft end of the semi-solid shaft reverse double impeller are all provided with splines for cooperating with the spline grooves, and the splines are provided with threaded blind holes corresponding to the countersunk threaded holes, and the threaded blind holes are connected to the countersunk threaded holes by countersunk bolts.

3. The self-balancing segmented multi-stage centrifugal pump according to claim 2, characterized in that: The half-impeller shell includes an outer shell, and a sleeve and a lip are respectively provided at both ends of the outer shell. The inner side of the outer shell is provided with a partition that divides the inner side of the outer shell into two interconnected spaces, front and rear. The impeller mounting hole is provided in the center of the partition. The outer side of the outer shell is provided with a plurality of axial positioning protrusions distributed at intervals. One end of the axial positioning protrusion is provided with a positioning blind hole and the other end thereof is provided with a positioning pin for cooperating with the positioning blind hole.

4. The self-balancing segmented multi-stage centrifugal pump according to claim 3, characterized in that: The side of the partition opposite to the guide vane is a stepped structure. The guide vane includes an annular blade segment corresponding to the plate surface of the partition. One side of the annular blade segment cooperates with the supporting ring convex support arranged on the back of the solid shaft single impeller. The inner side of the annular blade segment is provided with multiple support segments connected to the partition, and a guide channel for passing fluid is formed between adjacent support segments.

5. The self-balancing segmented multi-stage centrifugal pump according to claim 1 or 4, characterized in that: A spacer sleeve is provided between the semi-solid shaft reverse double impeller and the balancing disk. The balancing seat is provided with an axial countersunk groove at one end facing the spacer sleeve. The end of the balancing disk is provided with a limiting shoulder that cooperates with the axial countersunk groove.

6. The self-balancing segmented multi-stage centrifugal pump according to claim 5, characterized in that: The balancing disc is provided with an annular track on the side facing away from the limiting shoulder, and a spring joint is provided in the track. The spring joint is provided at one end of the spiral spring. The spiral radius of the spiral spring gradually increases from the spring joint and a plurality of fixing parts are provided on the end circle thereof. The fixing parts are provided on the inner wall of the balancing chamber.

7. The self-balancing segmented multi-stage centrifugal pump according to claim 1, characterized in that: A buffer sealing cavity is provided at the center of the front shell assembly, a baffle connected to the pump shaft is provided inside the buffer sealing cavity, sealing springs distributed on both sides of the baffle are provided in the buffer sealing cavity, and sealing flanges are provided at the ends of the sealing springs.

8. The self-balancing segmented multi-stage centrifugal pump according to claim 1, characterized in that: The shaft end of the semi-solid shaft turbine, the shaft ends of the solid shaft single impellers adjacent to each other and the semi-solid shaft reverse double impellers are all provided with wear-resistant brake pads.

9. The self-balancing segmented multi-stage centrifugal pump according to claim 1, characterized in that: A sealing ring is provided in the impeller mounting hole.

10. The self-balancing segmented multi-stage centrifugal pump according to claim 1, characterized in that: The outer peripheral surface of the spline hoop is provided with a bullnose perforation.

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