A multi-stage impeller pump unit system

Abstract

The application discloses a multistage impeller pump unit system and belongs to the pump unit field. The application is provided with an arc-shaped abutting part in the front part of each guide vane assembly along the axial direction and a plane abutting part in the rear part, the rear guide vane assembly is positioned by the abutting of the front arc-shaped abutting part and the plane abutting part in the rear part of the front guide vane assembly, the last guide vane is positioned by the abutting of the rear plane abutting part and the side wall plane of the front bearing seat, and a sealing area is formed below each arc-shaped abutting part, and a sealing piece is arranged in the sealing area. The application can effectively guarantee the installation precision between the multistage guide vanes and improve the sealing performance between the multistage guide vanes.

Description

Technical Field

[0001] This invention relates to the field of pump unit technology, and more specifically, to a multi-stage impeller pump unit system. Background Technology

[0002] A multistage impeller pump is a key piece of equipment that uses multiple impellers and guide vanes connected in series to transport high-pressure fluids. Its core advantage lies in its progressive pressurization, enabling it to achieve high head within a single pump while maintaining high hydraulic efficiency and operational stability. Compared to single-stage pumps, multistage pumps have a wider range of applications in petrochemical, power, water supply systems, and boiler feedwater industries.

[0003] In a multistage pump structure, the primary function of the guide vanes is to rectify the high-speed fluid at the impeller outlet, reduce eddy current losses, and convert kinetic energy into pressure energy. The installation accuracy and sealing performance of the multistage guide vanes directly affect the overall pump performance. If there is a deviation in the guide vane installation position, the installation error of a single stage may accumulate, easily leading to uneven fluid flow, periodic impacts, and consequently mechanical vibration and abnormal noise. Under long-term operation, vibration will accelerate the wear of critical components such as bearings and mechanical seals, and may even lead to fatigue fracture of the pump shaft, affecting the long-term stable operation of the pump. Furthermore, poor sealing is more likely to occur when installing multiple stages, leading to interstage leakage, energy loss, and reduced overall pump efficiency. Therefore, ensuring the precise installation and sealing of the guide vanes in a multistage impeller pump is crucial for reducing vibration and energy loss, and improving the overall performance and reliability of the pump. Summary of the Invention

[0004] 1. The technical problem that the invention aims to solve

[0005] To address the issue that poor installation between guide vanes in existing multi-stage impeller pumps negatively impacts overall pump performance, a proposed multi-stage impeller pump unit system is provided. This system effectively ensures the installation accuracy between guide vanes and improves the sealing performance between them, thereby reducing pump vibration and energy loss, and enhancing the overall performance and reliability of the pump.

[0006] 2. Technical Solution

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0008] The present invention discloses a multi-stage impeller pump unit system, including a base, a pump casing, and a front bearing housing pressed between the base and the pump casing. The pump shaft is installed in the base and extends through the front bearing housing into the pump casing. Multi-stage guide vane assemblies are respectively fitted onto the pump shaft inside the pump casing. The multi-stage guide vane assembly includes a first-stage guide vane and a last-stage guide vane. Each guide vane assembly has an arc-shaped abutment at the front and a planar abutment at the rear along the axial direction. The first-stage guide vane is positioned by abutting against the planar inner wall of the pump casing through the arc-shaped abutment at the front. The last-stage guide vane is positioned by abutting against the planar abutment at the rear of the first-stage guide vane assembly through the arc-shaped abutment at the front. The last-stage guide vane is positioned by abutting against the planar side wall of the front bearing housing through the planar abutment at the rear. A sealing area is formed below each arc-shaped abutment, and a sealing element is provided in the sealing area.

[0009] Furthermore, specifically, each stage guide vane assembly has an outer ring body coaxially surrounding the pump shaft, and a guide vane fitting area is formed within the outer ring body for the guide vane portion of the next stage guide vane assembly to fit into; the front end of the outer ring body has a forward bend that bends inward, and an arc-shaped transition portion a is formed between the forward bend and the outer ring body, and the forward bend extends radially from the outside to the inside towards the direction gradually approaching the tail end of the outer ring body; the tail end of the outer ring body has a backward bend that bends inward, and a flat portion d is formed radially on the outer wall surface of the backward bend;

[0010] When assembling the multi-stage guide vane assembly, the arc-shaped transition part a of the forward bend on the first-stage guide vane is positioned against the inner wall plane of the pump casing, the arc-shaped transition part a of the forward bend on the subsequent-stage guide vane is positioned against the flat part d of the rear bend on the previous-stage guide vane, and the flat part d of the rear bend on the last-stage guide vane is positioned against the side wall plane of the front bearing housing.

[0011] Furthermore, the front end of the outer ring body is provided with a coaxially distributed assembly ring, the front bend is connected between the outer ring body and the assembly ring, the front end of the assembly ring is provided with a radially extending front end cover, and the front end cover is provided with a through hole for the pump shaft to pass through.

[0012] The bottom end of the rear bend is bent axially toward the front bend to form an axially extending inner stop ring. An arc-shaped transition part b is formed between the inner stop ring and the rear bend. This ensures that when the multi-stage guide vane assembly is assembled, a variable diameter sealing area is formed between the front bend of the next stage guide vane assembly and the rear bend of the previous stage guide vane assembly, and the assembly ring of the next stage guide vane assembly and the inner stop ring of the previous stage guide vane assembly maintain an inner and outer coaxial clearance fit.

[0013] Furthermore, the pump casing includes an axially extending main casing, the front end of which has a radially extending end cap; and the middle of the end cap has an axially protruding end cap protrusion, and an arc-shaped transition portion c is formed between the end cap protrusion and the end cap, which forms a variable diameter sealing area with the front bend of the first-stage guide vane; the arc-shaped transition portion a of the front bend of the first-stage guide vane abuts against the inner wall plane of the end cap, and the assembly ring of the first-stage guide vane and the inner wall of the end cap protrusion maintain an inner and outer coaxial clearance fit.

[0014] Furthermore, the front bearing housing includes a radially extending main body, a shaft hole in the middle of the main body for the pump shaft to pass through, and a first convex ring protruding axially on the wall surface of the main body facing the final stage guide vane.

[0015] The planar portion d of the rear bend on the last stage guide vane abuts against the planar wall of the main body, and the outer wall of the first convex ring portion maintains a coaxial clearance fit with the inner stop ring on the last stage guide vane.

[0016] Furthermore, the front end cover of the final stage guide vane is provided with a guide vane portion, which is fitted into the inner cavity of the outer ring body of the previous stage guide vane assembly.

[0017] The guide vane section includes a positive guide vane and a negative guide vane arranged sequentially along the water flow direction. The negative guide vane is fixed on the front end cover. The front end of the positive guide vane is provided with a front connecting wall that extends radially. The outer edge of the front connecting wall is provided with a shaft extension that extends axially. The shaft extension of the subsequent guide vane assembly and the assembly ring of the previous guide vane assembly maintain an inner and outer coaxial clearance fit.

[0018] Furthermore, the front end of the shaft extension is provided with a radially inwardly extending radial extension, which maintains a clearance fit with the inner wall of the front end cover of the previous stage guide vane assembly.

[0019] Furthermore, the roughness of the upper plane d of the rear bend is less than 3.2, and the perpendicularity of the plane d reaches level 7-9, the flatness level of the plane d being less than the perpendicularity level; or / and, the angle between the inclined extension direction of the front bend and the radial extension direction of the outer ring body is 9°-45°.

[0020] Furthermore, the radius R2 of the arc transition portion b between the rear bend and the inner stop ring is greater than the radius R1 of the arc transition portion a between the front bend and the front end of the outer ring body; or, the radius R1 of the arc transition portion a between the front bend and the front end of the outer ring body is 1.2mm≤R1<2mm, and the radius R2 of the arc transition portion b between the rear bend and the inner stop ring is ≥2.5mm; or / and, the radius R3 of the arc transition portion c between the shell end cap and the end cap protrusion is ≥2.5mm.

[0021] Furthermore, the radial fit clearance between the assembly ring of the first-stage guide vane and the end cover protrusion of the pump casing, and the radial fit clearance between the assembly ring of the next-stage guide vane assembly and the inner stop ring of the previous-stage guide vane assembly are all controlled to be 0.02-0.2mm; the axial fit clearance between the radial extension of the next-stage guide vane assembly and the front end cover of the previous-stage guide vane assembly is ≥0.5mm.

[0022] 3. Beneficial effects

[0023] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0024] (1) The pump unit system of the present invention adopts a plane and arc surface contact positioning method between the first stage guide vane and the inner wall of the pump casing, as well as between the front and rear guide vane assemblies, to achieve a surface and line contact positioning method. It has a stronger self-adjustment function, forms an elastic line contact, improves positioning accuracy, avoids positioning tilt between multi-stage guide vane assemblies, and prevents the water pump from working normally. It can also form a continuous sealing line, and a sealing ring is provided in the formed sealing area to increase the sealing between guide vane assemblies at each stage, reduce the head and efficiency loss caused by inter-stage leakage, and improve the energy efficiency level of the water pump.

[0025] (2) In addition to using the contact positioning of the plane and the arc surface, the pump unit system of the present invention also uses the axial and radial clearance of other areas to position and install the adjacent guide vane components. This ensures the accuracy of the positioning and installation, avoids the situation where double positioning cannot be installed, and also reserves sufficient adjustment space for linear contact. It can also reduce fluid leakage and improve head and efficiency. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the pump unit in the embodiment;

[0027] Figure 2 This is a schematic diagram of the internal cross-sectional structure of the pump unit in the embodiment;

[0028] Figure 3 for Figure 2 A magnified schematic diagram of the partial structure at point A in the middle;

[0029] Figure 4 for Figure 2 A schematic diagram of a partial axial side view at point A in the middle;

[0030] Figure 5 This is a schematic diagram of the explosion state of the multi-stage guide vane arrangement in the embodiment;

[0031] Figure 6 This is a schematic diagram of the front bearing housing in the embodiment;

[0032] Figure 7This is a partially enlarged schematic diagram of the fit between the last stage guide vane and the front bearing housing in the embodiment.

[0033] Figure 8 This is a schematic diagram of the structure of the intermediate guide vane in the embodiment;

[0034] Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure of the middle guide vane;

[0035] Figure 10 This is a schematic diagram of the structure of the final stage guide vane in the embodiment.

[0036] Explanation of the labels in the diagram:

[0037] 100. Base; 101. Main body; 102. Pump shaft;

[0038] 200. Pump shell; 201. Main shell; 202. Shell end cover; 203. End cover convex part; 210. Seal;

[0039] 300. First-stage guide vane; 310. Intermediate guide vane; 320. Last-stage guide vane; 330. Guide vane section;

[0040] 301. Outer ring body; 302. Front bend; 303. Assembly ring; 304. Front end cover; 305. Rear bend; 306. Inner stop ring;

[0041] 311. Reverse guide vane; 312. Forward guide vane; 313. Front connecting wall; 314. Shaft extension; 315. Radial extension; 316. Rear connecting wall; 321. Outlet;

[0042] 400. Front bearing housing; 401. Inner main body; 402. Shaft hole; 403. Outer edge; 404. First convex ring; 405. Main body; 406. Second convex ring;

[0043] 500. Impeller. Detailed Implementation

[0044] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings.

[0045] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0046] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can be mechanical connections or electrical connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. The terms "first," "second," "third," and "fourth" should also be interpreted broadly, merely distinguishing feature names and not indicating a specific sequential relationship. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] The present invention will be further described below with reference to embodiments.

[0048] Example

[0049] Combination Figures 1-10 As shown, a multi-stage impeller pump unit system of this embodiment includes a base 100, a pump casing 200, and a front bearing seat 400 pressed between the base 100 and the pump casing 200. The pump shaft 102 is installed in the base 100 and extends through the front bearing seat 400 into the pump casing 200. Multi-stage guide vane assemblies are respectively fitted onto the pump shaft 102 in the pump casing 200. More specifically, the base 100 includes a main body 101, and a motor assembly is installed inside the main body 101, including the pump shaft 102, a rotor assembly, and a stator assembly. Multi-stage guide vane assemblies and multi-stage impellers 500 are installed inside the pump casing 200. The impellers 500 are correspondingly installed in the inner area of ​​the guide vanes of the guide vane assembly. The liquid thrown out by the impellers 500 is guided out through the guide vanes and flows to the next stage impeller 500 to achieve multi-stage pressurization of the water flow and finally guide the liquid to the high-pressure area for discharge.

[0050] In this embodiment, the multi-stage guide vane assembly includes a first-stage guide vane 300 and a last-stage guide vane 320, so as to... Figure 3Taking the three-stage guide vane assembly shown as an example, it includes a first-stage guide vane 300, intermediate guide vanes 310, and a last-stage guide vane 320. When there are three or more stages, there are multiple sets of intermediate guide vanes 310. Each stage guide vane assembly has an arc-shaped abutment at the front and a flat abutment at the rear along the axial direction. The first-stage guide vane 300 is positioned by contacting and abutting against the inner wall of the pump casing 200 through the arc-shaped abutment at the front. The next stage guide vane assembly is positioned by contacting and abutting against the flat abutment at the rear of the previous stage guide vane assembly through the arc-shaped abutment at the front. The last stage guide vane 320 is positioned by contacting and abutting against the side wall of the front bearing housing 400 through the flat abutment at the rear. A sealing area is formed below each arc-shaped abutment, and a sealing element 210 is provided in the sealing area. The use of arc-shaped abutment and flat abutment for surface-line contact positioning helps to fully ensure the accuracy of the fitting of each stage of guide vane assembly, ensure coaxiality with pump shaft 102, improve fitting sealing, and at the same time utilize the area below the surface-line contact area to form a further sealing zone, fitting the sealing element 210 for full sealing, specifically using O-ring seals.

[0051] More specifically, combined Figures 2-5 As shown, the preferred structure of the guide vane assembly is as follows: each stage guide vane assembly has an outer ring body 301 coaxially surrounding the pump shaft 102, and a guide vane fitting area is formed within the outer ring body 301 for the guide vane portion 330 of the next stage guide vane assembly to fit into; the front end of the outer ring body 301 is bent inward to form a forward bend 302, and an arc-shaped transition portion a is formed between the forward bend 302 and the outer ring body 301, such as... Figure 4 As indicated by the markings, the front bend 302 extends radially from the outside inward toward the tail end of the outer ring body 301; the tail end of the outer ring body 301 forms an inwardly bent rear bend 305, and a flat surface d is formed radially on the outer wall surface of the rear bend 305; when assembling the multi-stage guide vane assembly, the arc-shaped transition a is used as the arc-shaped abutment, and the flat surface d is used as the flat surface abutment. The arc-shaped transition a of the front bend 302 on the first-stage guide vane 300 abuts against the inner wall plane of the pump casing 200 for positioning, the arc-shaped transition a of the front bend 302 on the next-stage guide vane abuts against the flat surface d of the rear bend 305 on the previous-stage guide vane for positioning, and the flat surface d of the rear bend 305 on the last-stage guide vane 320 abuts against the side wall plane of the front bearing seat 400 for positioning.

[0052] By employing the above method, a planar and arc-shaped contact positioning method is used between the first-stage guide vane 300 and the inner wall of the pump casing 200, as well as between the front and rear guide vane assemblies. This achieves a surface-to-line contact positioning method, which effectively reduces the requirements for the flatness of the rear bend 305 planar portion d and the inner wall of the pump casing 200, as well as the parallelism requirements of the rear bend 305 planar portion d relative to the arc-shaped transition portion a on the front bend 302. Furthermore, this contact method has a stronger self-adjusting function. The line contact between the arc-shaped transition portion a of the front bend 302 and the planar portion d of the rear bend 305 allows for slight elastic deformation of the material near the contact area, forming an "elastic line contact." By coordinating local unevenness through deformation, a continuous sealing line can be formed, increasing the sealing performance between the guide vane assemblies at each stage. This linear contact positioning method also avoids the flatness errors inherent in traditional surface contact, especially the cumulative errors between multi-stage guide vane assemblies, which can lead to positioning tilting, poor coaxiality with the pump shaft 102, pump vibration and abnormal noise, or even malfunction. This linear contact also further distributes stress evenly along the contact line, preventing stress concentration that could cause deformation of the contact surface and affect positioning accuracy.

[0053] Furthermore, in the guide vane assembly structure, the front end of the outer ring body 301 is also provided with a coaxially distributed assembly ring 303, and the front bending part 302 is connected between the outer ring body 301 and the assembly ring 303. The front bending part 302 and the assembly ring 303 are also smoothly connected. The front end of the assembly ring 303 is provided with a radially extending front end cover 304, and the front end cover 304 is provided with a through hole for the pump shaft 102 to pass through. The bottom end of the rear bend 305 continues to bend axially toward the front bend 302 to form an axially extending inner stop ring 306. An arc-shaped transition part b is formed between the inner stop ring 306 and the rear bend 305. When the multi-stage guide vane assembly is assembled, the rear bend 305 and inner stop ring 306 of the previous stage, together with the front bend 302 and assembly ring 303 of the next stage, form a variable diameter sealing area that is close to a triangular cross section. That is, the space of the area increases radially inward, providing appropriate space for the sealing ring installation. When the two stages of the guide vane assembly are in line contact and positioned, they can effectively compress the sealing ring. This improves the sealing performance between the guide vane assemblies, further reduces the head and efficiency loss caused by inter-stage leakage, and improves the pump energy efficiency rating. In practice, the assembly ring 303 of the next-stage guide vane assembly corresponds to the inner stop ring 306 of the previous-stage guide vane assembly, and maintains a coaxial clearance fit. In practice, the radial fit clearance is preferably 0.02-0.2mm. The inner stop ring 306 of the previous-stage guide vane assembly forms a radial positioning for the next-stage guide vane assembly, which not only ensures the accuracy of positioning and installation, but also avoids the situation where double positioning cannot be installed. At the same time, it also reserves sufficient adjustment space for linear contact and can reduce the amount of fluid leakage from the high-pressure area to the low-pressure area in the guide vane, thereby improving the head and efficiency.

[0054] Specifically, in practice, the arc-shaped transition portion a between the front bending portion 302 and the front end of the outer ring body portion 301 is preferably controlled to have an arc radius R1 between 1.2mm and 2mm, and can be formed by stretching to form an arc surface without secondary processing. Furthermore, it is preferable that the angle between the inclined extension direction of the front bend 302 and the radial extension direction of the outer ring body 301 is 9°-45°, such as 9°, 15°, 30°, 45°, etc., to avoid bending and breakage, and to form a sufficiently large diameter-changing sealing area with a triangular cross section. The rear bend 305 and the tail end of the outer ring body 301 are also smoothly transitioned by stretching and forming an arc. The outer wall surface of the radially extending rear bend 305 is further processed to form a flat part d. It is preferable to control the roughness of the flat part d to be less than 3.2, and the perpendicularity of the flat part d to meet the requirements of grade 7-9. The flatness grade of the flat part d is lower than the perpendicularity grade, such as a flatness grade of 7 and a perpendicularity grade of 8 or 9, etc., to ensure that when the last stage guide vane 320 is installed, the flat part d and the side wall plane of the front bearing seat 400 are closely abutted and positioned, and the sealing performance is strong. The rear bend 305 and the inner stop ring 306 are connected by a large arc transition. The arc radius R2 of the arc transition part b is greater than the arc radius R1 of the arc transition part a between the front bend 302 and the outer ring body 301. Specifically, R2 is controlled to be ≥2.5mm to facilitate the formation of a variable diameter sealing area.

[0055] To achieve line contact fit between the first-stage guide vane 300 and the pump casing 200, and the formation of the variable diameter sealing zone, in practice, the pump casing 200 can be preferably designed as follows: the pump casing 200 includes an axially extending main casing 201, the front end of the main casing 201 has a radially extending end cap 202; and the middle of the end cap 202 is provided with an axially protruding end cap protrusion 203, and an arc-shaped transition portion c is also formed between the end cap protrusion 203 and the end cap 202. Similarly, the radius R3 of the arc-shaped transition portion c is controlled to be ≥2.5mm. A variable diameter sealing area is formed between the transition portion c and the front bend portion 302 of the first-stage guide vane 300; the arc-shaped transition portion a of the front bend portion 302 of the first-stage guide vane 300 abuts against the inner wall plane of the end cover 202, and the assembly ring portion 303 of the first-stage guide vane 300 and the inner wall of the end cover protrusion 203 maintain an inner and outer coaxial clearance fit. Similarly, the radial fit clearance is preferably 0.02-0.2mm to avoid the situation where double positioning cannot be installed, to reserve sufficient adjustment space for linear contact, and to reduce fluid leakage.

[0056] Combination Figures 3-6As shown, the front bearing housing 400 can be further designed as follows: it includes a radially extending main body 405, with a shaft hole 402 in the middle for the pump shaft 102 to pass through, and a first convex ring 404 protruding axially on the wall surface of the main body 405 facing the final stage guide vane 320; the flat surface d of the rear bend 305 on the final stage guide vane 320 abuts against and is positioned against the flat wall surface of the main body 405, and the outer wall of the first convex ring 404 maintains a coaxial clearance fit with the inner stop ring 306 on the final stage guide vane 320, preferably with a radial clearance of 0.02-0.2 mm. Axial planar abutment positioning is achieved by the cooperation between the main body 405 of the front bearing housing 400 and the rear bend 305 on the final stage guide vane 320, and radial positioning is achieved by the cooperation between the first convex ring 404 of the front bearing housing 400 and the inner stop ring 306 of the final stage guide vane 320.

[0057] More specifically, combining Figure 5 and Figure 6 The outer edge of the main body 405 of the front bearing housing 400 is the outer edge 403. The inner surface of the outer edge 403 has an axially protruding second convex ring 406 facing the pump housing 200. The main housing 201 of the pump housing 200 is fitted onto the outer periphery of the second convex ring 406 and abuts against and presses against the outer edge 403, thereby pressing the front bearing housing 400 between the pump housing 200 and the main seat 101 of the base 100. A sealing ring can be provided between the main housing 201 and the second convex ring 406 for sealing. The first convex ring 404 and the second convex ring 406 are coaxially distributed on the inner side of the main body 405, and a radially extending inner main body 401 is formed between the annular ends of the first convex ring 404. The shaft hole 402 is opened at the center of the inner main body 401.

[0058] In this embodiment, further, the front end cap 304 of the intermediate guide vane 310 and the final guide vane 320 is also provided with a guide vane portion 330, which is fitted into the inner cavity of the outer ring body portion 301 of the preceding stage guide vane assembly; while the first stage guide vane 300 does not need to be provided with a guide vane portion 330, and the outer ring body portion 301 of the final stage guide vane 320 is provided with multiple outlet holes 321 to facilitate the flow of pressurized liquid to the high-pressure zone for discharge. Specifically, in conjunction with Figures 8-10As shown, the guide vane section 330 includes a positive guide vane 312 and a negative guide vane 311 arranged sequentially along the water flow direction. The negative guide vane 311 is fixed on the front end cover 304. The front end of the negative guide vane 311 is connected to the positive guide vane 312 through the rear connecting wall 316. The front end of the positive guide vane 312 is provided with a radially extending front connecting wall 313. The outer edge of the front connecting wall 313 is provided with an axially extending shaft extension 314. When the multi-stage guide vane assembly is assembled, the shaft extension 314 of the subsequent stage guide vane assembly and the inner wall of the assembly ring 303 of the previous stage guide vane assembly maintain an inner and outer coaxial clearance fit, specifically a radial clearance of 0.02-0.2 mm. Furthermore, the front end of the shaft extension 314 is provided with a radially inwardly extending radial extension 315. The radial extension 315 of the next stage guide vane assembly maintains a clearance fit with the inner wall of the front end cover 304 of the previous stage guide vane assembly. Specifically, the axial clearance is a fit clearance ≥ 0.5 mm, to ensure that the shaft extension 314 does not contact the front end cover 304 of the previous stage guide vane assembly, and to avoid the situation of double positioning at both ends of the same stage guide vane assembly affecting installation.

[0059] The multi-stage impeller pump unit system of this embodiment utilizes the limiting and sealing fit between multiple adjacent guide vane assemblies, between the first-stage guide vane 300 and the pump casing 200, and between the last-stage guide vane 320 and the front bearing seat 400. This effectively improves the installation accuracy of the multi-stage guide vane assembly, ensures its coaxiality with the pump shaft 102, and improves the sealing performance, thereby comprehensively enhancing the overall performance of the pump unit.

[0060] The scope of protection of this invention is defined only by the claims. Thanks to the teachings of this invention, those skilled in the art will readily recognize that alternative structures to the structures disclosed herein can be used as feasible alternative implementations, and that the implementations disclosed herein can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. A multi-stage impeller pump unit system, comprising a base (100), a pump shell (200), and a front bearing seat (400) compressed between the base (100) and the pump shell (200), a pump shaft (102) installed in the base (100) and extending through the front bearing seat (400) into the pump shell (200); a plurality of guide vane assemblies corresponding to the pump shaft (102) are respectively sleeved in the pump shell (200), characterized in that: the plurality of guide vane assemblies comprise a first guide vane (300) and a last guide vane (320), each guide vane assembly has an arc-shaped abutting portion at the front part in the axial direction and a planar abutting portion at the rear part, the first guide vane (300) is positioned by the arc-shaped abutting portion at the front part and the planar abutting portion of the inner wall of the pump shell (200), the guide vane assembly at the rear part is positioned by the arc-shaped abutting portion at the front part and the planar abutting portion at the rear part of the guide vane assembly at the front part, and the last guide vane (320) is positioned by the planar abutting portion at the rear part and the side wall of the front bearing seat (400), and a sealing area is formed below each arc-shaped abutting portion, and a sealing element (210) is arranged in the sealing area. Each guide vane assembly has an outer ring body portion (301) coaxially surrounding the outer periphery of the pump shaft (102), and a guide vane fitting area is formed in the outer ring body portion (301) for fitting and embedding of the front guide vane portion (330) of the guide vane assembly at the rear part; 2. A multi-stage impeller pump assembly system as claimed in claim 1, wherein: the front end of the outer ring body portion (301) is inwardly bent to form a front bent portion (302), the arc-shaped transition portion a is formed between the front bent portion (302) and the outer ring body portion (301), and the front bent portion (302) extends along the radial direction from the outside to the inside and gradually inclines towards the tail end of the outer ring body portion (301); the tail end of the outer ring body portion (301) is inwardly bent to form a rear bent portion (305), and a planar portion d is formed on the outer wall surface of the rear bent portion (305) along the radial direction; when the plurality of guide vane assemblies are assembled, the arc-shaped transition portion a is used as the arc-shaped abutting portion, and the planar portion d is used as the planar abutting portion, the arc-shaped transition portion a of the front bent portion (302) of the first guide vane (300) is positioned by abutting to the inner wall of the pump shell (200), the arc-shaped transition portion a of the guide vane assembly at the rear part is positioned by abutting to the planar portion d of the guide vane assembly at the front part, and the planar portion d of the rear bent portion (305) of the last guide vane (320) is positioned by abutting to the side wall of the front bearing seat (400). the front end of the outer ring body portion (301) is further provided with an assembly ring portion (303) coaxially distributed, the front bent portion (302) is connected between the outer ring body portion (301) and the assembly ring portion (303), the front end of the assembly ring portion (303) is provided with a front end cover (304) extending in the radial direction, and the front end cover (304) is provided with a through hole for the pump shaft (102) to pass through.

3. A multi-stage impeller pump assembly system as claimed in claim 2, wherein: ​ The bottom end of the rear bending part (305) is bent in the direction of approaching the front bending part (302) in the axial direction, forming an inner stop ring (306) extending in the axial direction, and an arc-shaped transition part b is formed between the inner stop ring (306) and the rear bending part (305); so that when the multi-stage guide vane assembly is assembled, the front bending part (302) of the lower-stage guide vane assembly and the rear bending part (305) of the upper-stage guide vane assembly form a variable-diameter sealing area, and the assembly ring part (303) of the lower-stage guide vane assembly and the inner stop ring (306) of the upper-stage guide vane assembly are kept in the same coaxial gap fit.

4. A multi-stage impeller pump assembly system as claimed in claim 3, wherein: The pump shell (200) comprises an axially extending main shell (201), the front end of the main shell (201) is provided with a radially extending shell end cover (202); and the middle part of the shell end cover (202) is provided with an axially protruding end cover protruding part (203), and an arc-shaped transition part c is formed between the end cover protruding part (203) and the shell end cover (202), which corresponds to the formation of a variable-diameter sealing area between the arc-shaped transition part a of the front bending part (302) of the first-stage guide vane (300); the arc-shaped transition part a of the front bending part (302) of the first-stage guide vane (300) abuts against the inner wall plane of the shell end cover (202), and the assembly ring part (303) of the first-stage guide vane (300) and the inner wall of the end cover protruding part (203) are kept in the same coaxial gap fit.

5. A multi-stage impeller pump assembly system as claimed in claim 3, wherein: The front bearing seat (400) comprises a radially extending main body part (405), the middle part of the main body part (405) is provided with an axial hole (402) for the pump shaft (102) to pass through, and a first protruding ring part (404) protruding in the axial direction is arranged on the wall surface of the main body part (405) facing the last-stage guide vane (320); The plane part d of the rear bending part (305) of the last-stage guide vane (320) abuts against and contacts the plane wall surface of the main body part (405), and the outer wall of the first protruding ring part (404) and the inner stop ring (306) on the last-stage guide vane (320) are kept in the same coaxial gap fit.

6. A multi-stage impeller pump assembly system as claimed in claim 2, wherein: The front end cover (304) of the last-stage guide vane (320) is provided with a guide vane part (330), which is embedded in the inner cavity of the outer ring body part (301) of the front-stage guide vane assembly. The guide vane part (330) comprises a forward guide vane (312) and a reverse guide vane (311) arranged in sequence in the water flow direction, the reverse guide vane (311) is fixed on the front end cover (304), and the forward guide vane (312) is provided with a radially extending front connecting wall (313) at the front end, and the outer edge of the front connecting wall (313) is provided with an axially extending shaft extension part (314); the shaft extension part (314) of the rear-stage guide vane assembly and the assembly ring part (303) of the front-stage guide vane assembly are kept in the same coaxial gap fit.

7. A multi-stage impeller pump assembly system as claimed in claim 6, wherein: The front end of the shaft extension part (314) is provided with a radially inward extending radial extension part (315), and the radial extension part (315) and the inner wall of the front end cover (304) of the front-stage guide vane assembly are kept in the gap fit.

8. A multi-stage impeller pump assembly system as claimed in claim 2, wherein: The roughness of the flat surface d of the rear bending part (305) is less than 3.2, the perpendicularity grade of the flat surface d reaches 7-9, and the flatness grade of the flat surface d is less than the perpendicularity grade; or / and, the included angle between the inclined extension direction of the front bending part (302) and the radial extension direction of the outer ring body part (301) is 9°-45°.

9. A multi-stage impeller pump assembly system as claimed in claim 4, wherein: The arc radius R2 of the arc transition part b between the rear bending part (305) and the inner stop ring (306) is greater than the arc radius R1 of the arc transition part a between the front bending part (302) and the front end of the outer ring body part (301); or, the arc radius R1 of the arc transition part a between the front bending part (302) and the front end of the outer ring body part (301) is 1.2mm≤R1≤2mm, the arc radius R2 of the arc transition part b between the rear bending part (305) and the inner stop ring (306) is R2≥2.5mm; or / and, the arc radius R3 of the arc transition part c between the shell end cover (202) and the end cover protrusion (203) is R3≥2.5mm.

10. A multi-stage impeller pump assembly system as claimed in claim 4, wherein: The radial fitting gap between the assembly ring part (303) of the first-stage guide vane (300) and the end cover protrusion (203) of the pump shell (200), and the radial fitting gap between the assembly ring part (303) of the next-stage guide vane assembly and the inner stop ring (306) of the previous-stage guide vane assembly are both controlled to be 0.02-0.2mm; The front end of the next-stage guide vane assembly is provided with a radial extension part (315) extending radially inward, the radial extension part (315) is gap-fitted with the inner wall of the front end cover (304) of the previous-stage guide vane assembly, and the axial fitting gap between the radial extension part (315) and the front end cover (304) of the previous-stage guide vane assembly is ≥0.5mm.

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