Self-balancing sectional multi-stage centrifugal pump

Abstract

The invention belongs to the field of centrifugal pumps, and provides a self-balancing sectional multi-stage centrifugal pump which comprises a motor, a pump body, a coupler, a front pump shaft, a rear pump shaft, a bearing, a front shell assembly, a rear shell assembly, a long rod clamping bolt, a first blade assembly, a middle blade assembly, a tail blade assembly, a water inlet pipe opening, a water outlet pipe opening, a balance pipe, a balance seat and a balance disc. The front blade assembly and the middle blade assembly are both single-impeller assemblies, the tail blade assembly is a double-impeller assembly and comprises a tail blade shell and a semi-solid shaft reverse double-impeller, and a semi-solid shaft turbine is arranged in the front shell assembly. The shaft end of the semi-solid shaft turbine, the shaft end of the solid shaft single impeller and the shaft end of the semi-solid shaft reverse double impeller are sequentially connected through a plurality of spline hoops, the front pump shaft is in transmission connection to the semi-solid shaft turbine from front to back, and the rear pump shaft is in transmission connection to the semi-solid shaft reverse double impeller from back to front. The self-balancing system is reasonable in design, good in self-balancing effect, convenient to disassemble and maintain and beneficial to improving 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 segmental multi-stage centrifugal pump. Background Art

[0002] Centrifugal pumps are available in various forms, such as vertical, horizontal, single-stage, multi-stage, single-suction, double-suction, and self-priming. Centrifugal pumps work by rotating the impeller to cause water to undergo centrifugal motion. Before starting the water pump, fill the pump casing and the suction pipe with water, then start the motor so that the pump shaft drives the impeller and water to rotate at high speed, causing the water to undergo centrifugal motion and be thrown to the outer edge of the impeller, flowing into the water pressure pipeline of the water pump through the flow channel of the volute pump casing. A multistage centrifugal pump has two or more impellers on the pump shaft. Since the pump shaft of a multistage centrifugal pump has an axial flow of 2 to 5 mm during operation, some multistage centrifugal pumps use a double suction method to achieve self-balancing, such as the single-shell segmented self-balancing horizontal multistage centrifugal pump disclosed in CN204163994U. Some multistage centrifugal pumps generally add a balancing disc and a balancing pipe structure on the tail blade side, such as a new type of double-balanced structure multistage centrifugal pump disclosed in CN115596674A, thereby achieving self-balancing.

[0003] The existing patent CN102913452A is a first-stage positively symmetrical double-suction segmented multistage centrifugal pump, including a pump shaft and a plurality of 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, and the ends of the symmetrically arranged impeller groups are arranged face to face. The impeller groups at the suction end of the centrifugal pump and the discharge end of the centrifugal pump are evenly arranged in the same direction. A 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 reverse impeller. The first-stage impeller is equipped with a first-stage guide vane, and the first-stage reverse impeller is equipped with a first-stage reverse guide vane. The axial forces generated by the first-stage impeller and the first-stage reverse impeller are equal in magnitude and opposite in direction. In addition to the design of the balance disc and the balance pipe, the multistage centrifugal pump also proposes the design of positive and reverse first blades. However, such centrifugal pumps have the following problems in actual operation: first, one interface of the balancing pipe used 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 one side of the impeller and the other side of the balancing disc. 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 the 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 arranged at the edge of the impeller where the water flows out. They generally only play a role in diversion, and the diversion path relies on fluid power and inertia to enter the next impeller when the water flows to the back of the 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, and the motor and pump body are usually connected to the base of the workshop or pump room, which increases the workload of disassembly and maintenance. Summary of the invention

[0004] In view of the technical problems existing in the above-mentioned centrifugal pumps, the present invention proposes a self-balancing segmental 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 that a self-balancing segmented multi-stage centrifugal pump provided by the present invention includes 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, a balancing pipe connected to the rear shell assembly is provided on the water inlet, 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, and the first blade assembly and the middle blade assembly are A single impeller assembly and single impeller assemblies adjacent to each other in front and behind are nested with each other, the single impeller assembly includes a pair of half impeller shells, the center of the half impeller shells is provided with an impeller mounting hole, the half impeller shells are provided with guide vanes on the front side of the impeller mounting hole, a solid shaft single impeller is provided in the impeller mounting hole, the tail blade assembly is a double impeller assembly, the double impeller assembly includes a tail blade shell, a semi-solid shaft reverse double impeller is provided inside the tail blade shell, a semi-solid shaft turbine is provided inside the front shell assembly, the shaft end of the semi-solid shaft turbine, the solid shaft single impeller adjacent to each other in front and behind, and the shaft end of the semi-solid shaft reverse double impeller are sequentially connected through a plurality of 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.

[0006] Preferably, the spline hoop comprises a pair of half-hoop sleeves, a plurality of spline grooves are arranged on the inner side of the half-hoop sleeves, a plurality of pairs of countersunk threaded holes are arranged on the half-hoop sleeves and 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, 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 at 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, one side of the annular blade segment cooperates with a supporting ring convex support arranged on the back of the solid shaft single impeller, and a plurality of supporting segments connected to the partition are arranged on the inner side of the annular blade segment, 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, an axial countersunk groove is provided at one end of the balancing seat facing the spacer sleeve, and a limiting shoulder cooperating with the axial countersunk groove is provided at the end of the balancing disk.

[0010] Preferably, the balancing plate 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 at the center of the front shell assembly, a baffle plate connected to the pump shaft is provided inside the buffer sealing cavity, a sealing spring distributed on both sides of the baffle plate 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 in front and behind, and the shaft ends of 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 holes.

[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 the design of a double impeller assembly for the tail blade assembly, thereby being able to balance 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 vane of the self-balancing segmented multi-stage centrifugal pump provided by the present invention can not only play the role of guiding flow, but also reduce the real-time influence of the fluid pressure on the rear side of the solid shaft single impeller, and 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 beneficial to reduce the workload of disassembly and maintenance. The design is reasonable and beneficial 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 briefly introduces 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 creative work.

[0020] Figure 1 A three-dimensional diagram 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 Sectional view of the self-balancing segmental multistage centrifugal pump in the GG direction;

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

[0025] Figure 6 for Figure 3 Sectional view of the self-balancing segmental multistage 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 hoop provided for an embodiment;

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

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

[0030] Fig.11An axonometric diagram of the distribution of the spiral spring provided in the embodiment inside 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 shell assembly; 51. Buffer seal chamber; 52. Baffle; 53. Sealing spring; 54. Sealing flange; 6. Rear shell assembly; 7. Long rod clamping bolt; 8. Single impeller assembly; 81. Half impeller shell; 811. Outer shell; 812. Sleeve; 813. Lip; 814. Partition; 815. Axial positioning protrusion; 816. Positioning blind hole; 817. Positioning pin; 82. Impeller mounting hole; 83. Guide vane; 831. Ring blade 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, scroll 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 in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. For the convenience of description, if the words "upper", "lower", "left" and "right" appear below, they only indicate that the upper, lower, left and right directions are consistent with the accompanying 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 of the following disclosure.

[0035] Examples, such as Figure 1-Figure 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, 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, 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, the water inlet pipe port 10 is provided with a balancing pipe 12 connected to the rear shell assembly 6, 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 as well as 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 equipment, the first blade assembly and the middle blade assembly provided by the present invention are both single impeller assemblies 8, and the single impeller assemblies 8 adjacent to each other are nested with each other. The single impeller assembly 8 includes a pair of half blade shells 81, and 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, and 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 the rear side thereof. The double impeller assembly 9 includes a tail blade shell 91, and 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 each other in front and rear, and the shaft end of the semi-solid shaft reverse double impeller 92 are sequentially connected through a plurality of spline hoops 17 in sequence. 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, and 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 a balancing disc 15 and a balancing pipe 12 to balance the axial flow, the present invention also adopts the design of a 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 directions inside the impellers are the same, but the directions of water inlet and outlet are different. In particular, the impeller facing the side of the balancing seat 14 can spit a portion of the water between the two toward 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 a portion 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 side 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 a role of axial support, while reducing the instability factors of the fluid, it plays a role in balancing the axial force, thereby further improving the self-balancing performance of the 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 by disassembling from the middle, which can effectively reduce the work intensity 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 Fig. 9As shown, the spline hoop 17 provided by the present invention includes a pair of half-hoop sleeves 171, a plurality of spline grooves 172 are arranged on the inner side of the half-hoop sleeve 171, a plurality of countersunk threaded holes 173 spaced apart from the spline grooves 172 are arranged on the half-hoop sleeve 171, 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 all provided with splines 174 for cooperating with the spline grooves 172, a threaded blind hole 175 corresponding to the countersunk threaded hole 173 is arranged on the spline 174, and the threaded blind hole 175 is connected to the countersunk threaded hole 173 by a countersunk bolt 176. Among them, the spline 174 and the spline groove 172 provide a plurality of key connection foundations, and the half-hoop sleeve 171 is buckled at the connection position of the front and rear solid shafts in a half-sleeve manner, and the countersunk bolt 176 plays a fixing role, thereby ensuring the synchronous transmission relationship of 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, the semi-solid shaft turbine 16 and the semi-solid shaft reverse double impeller 92. It should be noted that the diameter of the solid part 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 solid shaft single impeller 84 and the semi-solid shaft reverse double impeller 92 adjacent to each other are designed with splines, 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 which divides the inner side into two interconnected spaces, the impeller mounting hole 82 is arranged 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, and 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 sleeve 812 and the lip 813 of the adjacent single impeller assemblies 8 are nested with each other, which not only play a sealing role, but also play a docking and centering role; the working chamber of 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 designed to be open on the left and right during the disassembly and assembly process, which can reduce the assembly difficulty of the equipment; the axial positioning protrusion 815, on the one hand, increases the sealing surface of the front and rear single impeller assemblies 8, and on the other hand, provides a processing surface and a welding surface for the positioning pin 817 and the positioning blind hole 816, and the processed positioning pin 817 and the 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 the 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 to the guide vane 83 is 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 matched with a supporting ring convex 85 arranged on the back of the solid shaft single impeller 84, and a plurality of supporting segments 832 connected to the partition 814 are arranged on the inner side of the annular blade segment 831, and a guide channel for passing fluid is formed between adjacent supporting segments 832. Among them, the partition 814 and the guide vane 83 adopt a stepped design, and the formed guide channel includes a horizontal part and an inclined part, the end of the inclined part faces the water inlet of the solid shaft single impeller 84, and the water flow discharged from the edge of the impeller enters the horizontal part under the action of kinetic energy and inertia, and then flows along the inclined part to the water inlet of the solid shaft single impeller 84. In this case, the annular blade segment 831 and the solid shaft single impeller 84 have a certain overlapping coverage range in the axial direction, and part of the pressure of the fluid in the overlapping range directly acts on the half blade shell 81, reducing the pressure acting on the back of the solid shaft single impeller 84. In addition, 2-3 supporting ring protrusions 85 can be designed on the back of the solid shaft single impeller 84. On the basis of ensuring the fluid path connection, the annular blade segment 831 can reasonably support the back of the solid shaft single impeller 84, balancing part of the axial thrust, thereby improving the self-balancing performance of the device.

[0042] In order to improve the self-balancing performance, a spacing sleeve 18 is arranged between the semi-solid shaft reverse double impeller 92 and the balancing disc 15 of the present invention, an axial countersunk 141 is arranged at one end of the balancing seat 14 facing the spacing sleeve 18, and a limiting shoulder 151 cooperating with the axial countersunk is arranged at the end of the balancing disc 15. Among them, the spacing sleeve 18 plays the role of spacing the balancing disc 15 and the semi-solid shaft reverse double impeller 92, and can transmit axial force to the balancing disc 15; the balancing disc 15 and the balancing seat 14 form a set of limiting mechanisms through the nesting design of the axial countersunk 141 and the limiting shoulder 151, and ensure that the balancing cavity 13 and the working cavity of the semi-solid shaft reverse double impeller 92 are under the basic condition of relative isolation, and ensure that the balancing range of the balancing disc 15 is within a controllable range, which is larger than the original 2-5mm axial drift, so that the device can avoid occasionally entering the pressure holding operation condition, thereby ensuring the actual working performance of the device, and to a certain extent, it is also conducive to improving the actual service life of the device.

[0043] Furthermore, the present invention provides an annular track 152 on the side of the balancing disc 15 facing away from the limiting shoulder, and a spring joint 191 is provided in the track 152. The spring joint 191 is provided at one end of the spiral spring 19. The spiral radius of the spiral spring 19 gradually increases from the spring joint 191 and a plurality of fixing members 192 are provided on the end circle thereof. The fixing members 192 are provided on the inner wall of the balancing chamber 13. By designing the spiral spring 19 in the balancing chamber 13, a certain dynamic elastic force can be provided to the balancing disc 15, especially when the balancing disc 15 is in the moment 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 means of a side opening + end screw, so when the balancing disk 15 continuously rotates the pump shaft 32, the end of the spiral spring can always support the balancing disk 15, and the spiral spring itself does not produce a large degree of distortion.

[0044] In order to improve the relative sealing performance between the front pump shaft 31 and the front shell assembly 5, the present invention provides a buffer sealing cavity 51 at the center of the front shell assembly 5, a baffle 52 connected to the pump shaft 3 is provided inside the buffer sealing cavity 51, and sealing springs 53 distributed on both sides of the baffle 52 are provided in the buffer sealing cavity 51, and sealing flanges 54 are provided at the ends of the sealing springs 53. A pair of sealing flanges 54 are designed to seal the working cavity of the first blade assembly and the inner cavity of the front shell assembly 5. At the same time, the axial movement of the baffle 52 is synchronized with the axial movement of the front pump shaft 31. When the front pump shaft 31 is in the process of dynamic self-balancing, the two sealing flanges 54 are supported by the sealing springs 53, which can further ensure the actual service life of the bearing 4 inside the front shell assembly 5.

[0045] In order to improve the water pumping performance of the centrifugal pump, from the transmission aspect, the present invention is provided with a wear-resistant brake pad 20 at the shaft end of the semi-solid shaft turbine 16, the solid shaft single impeller 84 adjacent to each other in front and back, and the shaft end of the semi-solid shaft reverse double impeller 92. By installing the wear-resistant brake pad 20, the friction force and tension force of the shaft end of the semi-solid shaft turbine 16, the solid shaft single impeller 84 adjacent to each other in front and back, and the shaft end of the semi-solid shaft reverse double impeller 92 can be increased, thereby improving the synchronous driving performance of the impellers at different positions, and to a certain extent, the shear load of the countersunk bolt 176 on the spline hoop 17 can also be reduced to ensure the connection reliability of the spline hoop 17 at the shaft end position.

[0046] In order to reduce the reverse leakage of water at the installation node of the solid shaft single impeller 84, a sealing ring 21 is provided in the impeller installation hole 82 of the present invention. 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 inclined surfaces. 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 perforation 177 is provided on the outer peripheral surface of the spline hoop 17. After disassembling the countersunk bolt 176, a special tool is inserted into the bull nose perforation 177 and hooked outward to remove the half hoop sleeve 171.

[0048] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A self-balancing segmented multistage centrifugal pump, comprising 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, a plurality of bearings are provided at both ends of the pump shaft, the pump body comprises 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 sequentially 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 disc are 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 with each other. The single impeller assembly includes a pair of half blade shells, the center of the half blade shells is provided with an impeller mounting hole, the half blade shells are provided with guide vanes 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, and a semi-solid shaft reverse double impeller is provided inside the tail blade shell. A semi-solid shaft turbine is provided inside the front shell assembly, and 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 are sequentially connected through a plurality of spline hoops in sequence. The pump shaft includes a front pump shaft and a rear pump shaft, and 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 multistage 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 arranged on the inner side of the half hoop sleeves, a plurality of pairs of countersunk threaded holes are arranged 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, 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 multistage 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. A partition is provided on the inner side of the outer shell to divide the inner side into two interconnected spaces, front and rear. The impeller mounting hole is provided at the center of the partition. A plurality of axial positioning protrusions distributed at intervals are provided on the outer side of the outer shell, and 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.

4. The self-balancing segmented multistage centrifugal pump according to claim 3, characterized in that: 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, one side of the annular blade segment cooperates with a supporting ring convex support arranged on the back of the solid shaft single impeller, and a plurality of supporting segments connected to the partition are arranged on the inner side of the annular blade segment, and a guide channel for passing fluid is formed between adjacent support segments.

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

6. The self-balancing segmented multistage centrifugal pump according to claim 5, characterized in that: The balancing plate 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 a circle at the end thereof, and the fixing parts are provided on the inner wall of the balancing chamber.

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

8. The self-balancing segmented multistage 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 in front and behind, and the shaft ends of the semi-solid shaft reverse double impellers are all provided with wear-resistant brake pads.

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

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

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