Multi-stage impeller pump guide vane sealing system

Abstract

The utility model discloses a multi-stage impeller pump guide vane sealing system, and belongs to the field of pump set guide vane sealing. Each stage of guide vane assembly comprises an outer ring body part, the front end of the outer ring body part is bent inwards to form a front bent part, and the rear end of the outer ring body part is bent inwards to form a rear bent part; among the multiple stages of guide vane assemblies, the front bent part of the rear stage of guide vane assembly abuts against the rear bent part of the front stage of guide vane assembly for positioning, a sealing area is formed on the inner side of the abutting area of the front bent part and the rear bent part, and a sealing piece is arranged in the sealing area. Primary leakage prevention is formed through abutting contact, the sealing area is further formed on the inner side of the abutting area, further sealing is conducted through the sealing piece, and liquid is prevented from leaking from the assembling gap of the two-stage guide vane assembly.

Description

Technical Field

[0001] This utility model relates to the field of pump guide vane sealing technology, and more specifically, to a multi-stage impeller pump guide vane sealing system. Background Technology

[0002] A multistage impeller pump is a key device that uses multiple impellers and guide vanes connected in series to transport high-pressure fluids. Its core advantage lies in the fact that by superimposing energy at each stage, it can achieve high head output in a compact structure while maintaining high operating efficiency and stability. Therefore, it is widely used in petrochemical, power systems, high-pressure boiler water supply, and long-distance pipeline transportation.

[0003] In multistage pump structures, the primary function of guide vanes is to rectify and convert the high-speed fluid at the impeller outlet. Poor sealing between adjacent guide vanes can lead to interstage leakage, where high-pressure fluid flows back to the low-pressure side, causing energy loss and reducing overall pump efficiency. Under high-pressure conditions, interstage leakage significantly increases eddy and turbulent losses, affecting the pump's head and flow characteristics, and even causing its performance curve to deviate from design conditions. Furthermore, when transporting high-temperature liquids, interstage leakage can even lead to localized cavitation, accelerating erosion damage to the impeller and guide vanes. Currently, the industry commonly installs floating wear rings in the impeller-guide vane mating area to reduce liquid backflow in the impeller region, but the sealing between multistage guide vanes is often neglected. Utility Model Content

[0004] 1. Technical problem to be solved by the utility model

[0005] In view of the problem that poor sealing between guide vanes in multi-stage impeller pumps can easily lead to inter-stage leakage, this utility model aims to provide a multi-stage impeller pump guide vane sealing system that can improve the sealing between guide vanes of each stage, reduce inter-stage leakage, and optimize the pump's head and flow characteristics.

[0006] 2. Technical Solution

[0007] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0008] This utility model discloses a multi-stage impeller pump guide vane sealing system, comprising a multi-stage guide vane assembly assembled sequentially along the axial direction. Each stage guide vane assembly includes an outer ring body. Along the water flow inlet direction, the front end of the outer ring body is bent inward to form a front bend, and the rear end is bent inward to form a rear bend. Between the multi-stage guide vane assemblies, the front bend of the subsequent stage guide vane assembly abuts against and is positioned against the rear bend of the preceding stage guide vane assembly. A sealing area is formed inside the abutting area of ​​the front bend and the rear bend, and a sealing element is provided in the sealing area.

[0009] Furthermore, an arc-shaped transition section a is formed between the front bend and the outer ring body, and a flat section d is formed radially on the outer wall surface of the rear bend; the two-stage guide vane assemblies are positioned by the arc-shaped transition section a and the flat section d abutting against each other.

[0010] Furthermore, the front end of the outer ring body also has a coaxially distributed assembly ring. The assembly ring is connected to the front end of the outer ring body through the front bend. The assembly ring of the subsequent stage guide vane assembly extends into the inner side of the rear bend of the preceding stage guide vane assembly, thereby forming a sealing area between the front bend, the assembly ring, and the rear bend of the preceding stage guide vane assembly.

[0011] Furthermore, the front bend extends radially from the outside inward toward the tail end of the outer ring body; the bottom end of the rear bend bends axially toward the front bend to form an inner stop ring, and an arc-shaped transition section b is formed between the inner stop ring and the rear bend; thus, a variable diameter sealing area is formed inside the abutment area of ​​the two-stage guide vane assembly.

[0012] Furthermore, it also includes a pump casing, a multi-stage guide vane assembly installed inside the pump casing, and an arc-shaped transition portion a on the first-stage guide vane of the multi-stage guide vane assembly abutting against the inner wall plane of the pump casing for positioning, and a sealing area is formed inside the abutting area, and a sealing element is provided in the sealing area.

[0013] Furthermore, the pump casing includes a main casing and a casing end cover; the arc-shaped transition portion a on the first-stage guide vane abuts against the inner wall plane of the casing end cover; and the middle of the casing end cover is provided with an axially protruding end cover protrusion, and an arc-shaped transition portion c is formed between the end cover protrusion and the casing end cover, thereby forming a variable diameter sealing area inside the abutting area between the first-stage guide vane and the casing end cover.

[0014] Furthermore, the surface roughness of the upper plane d of the back bend is less than 3.2, and the perpendicularity of the plane d reaches level 7-9, with the flatness level of the plane d being lower than the perpendicularity level.

[0015] Furthermore, the angle between the inclined extension direction of the front bend and the radial extension direction of the outer ring body is 9°-45°.

[0016] Furthermore, the radius R2 of the arc transition section b is greater than the radius R1 of the arc transition section a.

[0017] Furthermore, the radius of the arc of the arc transition section a is 1.2mm≤R1≤2mm, and the radius of the arc of the arc transition section b is R2≥2.5mm.

[0018] 3. Beneficial effects

[0019] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0020] (1) In the guide vane sealing system of this utility model, each stage of the guide vane assembly has a front bending part formed by bending inward at the front end of the outer ring body and a rear bending part formed by bending inward at the rear end. The front bending part and the rear bending part are used to abut and position to achieve contact installation. The abutting contact forms primary leakage prevention, and a sealing area is further formed inside the abutting area. The sealing element is used for further sealing to prevent liquid from leaking from the assembly gap of the two stages of the guide vane assembly, effectively improving the sealing performance.

[0021] (2) The guide vane sealing system of this utility model uses the arc transition part a and the flat part d to abut and position the two-stage guide vane components, realizing the contact positioning method of surface and line. It has a stronger self-adjustment function, allowing the material near the contact area to undergo slight elastic deformation to form "elastic line contact". By deforming and coordinating local unevenness, a continuous sealing line can be formed, further ensuring the sealing between the guide vane components of each stage.

[0022] (3) In the guide vane sealing system of this utility model, the front bend extends radially from the outside to the inside towards the tail end of the outer ring body, and together with the arc transition part b formed between the inner stop ring and the rear bend, they form a variable diameter sealing area with a cross section close to a triangle. It has an appropriate sealing ring installation space, and when the two-stage guide vane assemblies are in line contact and positioned, they can form an effective compression of the sealing ring, thus further improving the sealing performance between the guide vane assemblies. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the pump unit in the embodiment;

[0024] Figure 2 This is a schematic diagram of the internal cross-sectional structure of the pump unit in the embodiment;

[0025] Figure 3 for Figure 2 A magnified schematic diagram of the local structure at point A;

[0026] Figure 4 for Figure 2 A schematic diagram of a partial axial side view at point A in the middle;

[0027] Figure 5 This is a schematic diagram of the explosion state of the multi-stage guide vane assembly in the embodiment;

[0028] Figure 6 This is a schematic diagram of the front bearing housing in the embodiment;

[0029] Figure 7 This is a partially enlarged schematic diagram of the fit between the last stage guide vane and the front bearing housing in the embodiment.

[0030] Figure 8 This is a schematic diagram of the structure of the intermediate guide vane in the embodiment;

[0031] Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure of the middle guide vane;

[0032] Figure 10 This is a schematic diagram of the structure of the final stage guide vane in the embodiment.

[0033] Explanation of the labels in the diagram:

[0034] 100. Base; 101. Main body; 102. Pump shaft;

[0035] 200. Pump shell; 201. Main shell; 202. Shell end cover; 203. End cover convex part; 210. Seal;

[0036] 300. First-stage guide vane; 310. Intermediate guide vane; 320. Last-stage guide vane; 330. Guide vane section;

[0037] 301. Outer ring body; 302. Front bend; 303. Assembly ring; 304. Front end cover; 305. Rear bend; 306. Inner stop ring;

[0038] 311. Reverse guide vane; 312. Forward guide vane; 313. Front connecting wall; 314. Shaft extension; 315. Radial extension; 316. Rear connecting wall; 321. Outlet;

[0039] 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;

[0040] 500. Impeller. Detailed Implementation

[0041] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings.

[0042] In the description of this utility model, 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 utility model 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 utility model.

[0043] 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 utility model based on the specific circumstances.

[0044] The present invention will be further described below with reference to the embodiments.

[0045] Example

[0046] This embodiment provides a multi-stage impeller pump guide vane sealing system, including a multi-stage guide vane assembly assembled sequentially along the axial direction. Each stage guide vane assembly includes an outer ring body 301. Along the water flow inlet direction, the front end of the outer ring body 301 is bent inward to form a front bend 302, and the rear end is bent inward to form a rear bend 305. Between the multi-stage guide vane assemblies, the front bend 302 of the subsequent stage guide vane assembly abuts against and is positioned against the rear bend 305 of the previous stage guide vane assembly. A sealing area is formed inside the abutting area of ​​the front bend 302 and the rear bend 305, and a sealing element 210 is provided in the sealing area. In this design, the front bend 302 and the rear bend 305 are first used to abut and position the components to achieve contact installation. The abutment contact forms a primary leak-proof layer, and a sealing zone is further formed inside the abutment area. The sealing element 210 is used for further sealing, achieving a full seal between the two-stage guide vane assemblies. This prevents liquid from leaking from the assembly gap between the two-stage guide vane assemblies, effectively improving sealing performance and reducing leakage.

[0047] More specifically, in practice, an arc-shaped transition portion a is preferably formed between the front bend portion 302 and the outer ring body portion 301, and a flat portion d is formed radially on the outer wall surface of the rear bend portion 305; the two-stage guide vane assemblies are positioned by abutting against the arc-shaped transition portion a and the flat portion d, realizing a surface-to-line contact positioning method, which has a stronger self-adjusting function, allowing the material near the contact area to undergo slight elastic deformation, forming "elastic line contact". By coordinating local unevenness through deformation, a continuous sealing line can be formed, further ensuring the sealing performance between the guide vane assemblies of each stage.

[0048] Regarding the formation of the sealing area, it is preferable that the front end of the outer ring body 301 also has a coaxially distributed assembly ring 303. The assembly ring 303 is connected to the front end of the outer ring body 301 through the front bend 302. The assembly ring 303 of the subsequent stage guide vane assembly extends into the inner side of the rear bend 305 of the previous stage guide vane assembly, thereby forming a sealing area together between the front bend 302, the assembly ring 303 and the rear bend 305 of the previous stage guide vane assembly. In this way, the sealing area is formed while the guide vane assemblies of each stage are positioned and installed.

[0049] This embodiment typically provides a multi-stage impeller pump unit system using this sealing system to facilitate a more detailed and comprehensive description of the sealing system. Combined with... 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, combined with... Figures 2-5 As shown, taking a three-stage system as an example, it has a first-stage guide vane 300, intermediate guide vanes 310, and a final-stage guide vane 320. When using three or more stages, it has multiple sets of intermediate guide vanes 310. Each stage guide vane assembly has an outer ring body 301 coaxially surrounding the pump shaft 102. The outer ring body 301 forms a guide vane fitting area for the guide vane part 330 at the front end 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 part a is formed between the forward bend 302 and the outer ring body 301, such as... Figure 4As 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 portion d is formed radially on the outer wall surface of the rear bend 305; when the multi-stage guide vane assembly is assembled, the arc-shaped transition portion 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 portion a of the front bend 302 on the next-stage guide vane abuts against the flat portion d of the rear bend 305 on the previous-stage guide vane for positioning, and the flat portion 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.

[0051] 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, effectively reducing the requirements for the flatness of the rear bend 305 planar portion d and the inner wall of the pump casing 200, and 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, allowing 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. Simultaneously, this line contact positioning method 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.

[0052] 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 with a cross section close to a triangle. That is, the space of the radially inward area increases, 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.

[0053] 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 sufficient variable diameter sealing area. 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, if R2 is controlled to be ≥2.5mm, it is convenient to form a variable diameter sealing area, which is beneficial to the installation and compression sealing of the sealing ring.

[0054] To achieve line contact fit between the first-stage guide vane 300 and the pump casing 200, and the formation of a triangular sealing area, 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 having 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.

[0055] 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.

[0056] 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.

[0057] In this embodiment, further, the front end caps 304 of the intermediate guide vane 310 and the final guide vane 320 are also provided with guide vane portions 330, which are fitted into the inner cavity of the outer ring portion 301 of the preceding guide vane assembly; while the first-stage guide vane 300 does not need to be provided with guide vane portions 330, and the outer ring portion 301 of the final guide vane 320 is also 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.

[0058] 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.

[0059] The scope of protection of this utility model is defined only by the claims. Thanks to the teachings of this utility model, those skilled in the art will readily recognize that alternative structures to the disclosed structure can be used as feasible alternative implementations, and that the disclosed implementations can be combined to produce new implementations, which also fall within the scope of the appended claims.

Claims

1. A multi-stage impeller pump guide vane seal system comprising a plurality of guide vane assemblies sequentially assembled in an axial direction, characterized in that: Each guide vane assembly comprises an outer ring body (301), the front end of the outer ring body (301) is inwardly bent to form a front bending portion (302), and the rear end is inwardly bent to form a rear bending portion (305); between the multi-stage guide vane assemblies, the front bending portion (302) of the rear-stage guide vane assembly is positioned against the rear bending portion (305) of the front-stage guide vane assembly, and a sealing area is formed inside the abutting area of the front bending portion (302) and the rear bending portion (305), and a sealing element (210) is arranged in the sealing area.

2. A multiple stage impeller pump guide vane seal system as claimed in claim 1, wherein: An arc-shaped transition portion a is formed between the front bending portion (302) and the outer ring body (301), and a flat portion d is formed on the outer wall surface of the rear bending portion (305) in the radial direction; the arc-shaped transition portion a and the flat portion d are used to position the two-stage guide vane assemblies against each other.

3. A multiple stage impeller pump guide vane seal system as claimed in claim 1, wherein: The front end of the outer ring body (301) further has a coaxially distributed assembly ring portion (303), the assembly ring portion (303) is connected to the front end of the outer ring body (301) through the front bending portion (302), the assembly ring portion (303) of the rear-stage guide vane assembly extends into the inside of the rear bending portion (305) of the front-stage guide vane assembly, so as to enclose a sealing area between the front bending portion (302), the assembly ring portion (303) and the rear bending portion (305) of the front-stage guide vane assembly.

4. A multiple stage impeller pump guide vane seal system as claimed in claim 2, wherein: The front bending portion (302) extends in the radial direction of the outer ring body (301) from outside to inside towards the tail end of the outer ring body (301); the bottom end of the rear bending portion (305) is bent in the axial direction towards the front bending portion (302) to form an inner stop ring (306), and an arc-shaped transition portion b is formed between the inner stop ring (306) and the rear bending portion (305); so as to form a variable-diameter sealing area inside the abutting area of the two-stage guide vane assemblies.

5. A multiple stage impeller pump guide vane seal system as claimed in claim 4, wherein: The pump also comprises a pump shell (200), the multi-stage guide vane assemblies are installed in the pump shell (200), and the arc-shaped transition portion a of the first-stage guide vane (300) is positioned against the inner wall plane of the pump shell (200), and a sealing area is formed inside the abutting area, and a sealing element (210) is arranged in the sealing area.

6. A multiple stage impeller pump guide vane seal system as claimed in claim 5, wherein: The pump shell (200) comprises a main shell (201) and a shell end cover (202); the arc-shaped transition portion a of the first-stage guide vane (300) is positioned against the inner wall plane of the shell end cover (202); and the middle part of the shell end cover (202) is provided with an axially protruding end cover protrusion (203), and an arc-shaped transition portion c is formed between the end cover protrusion (203) and the shell end cover (202), so as to form a variable-diameter sealing area inside the abutting area of the first-stage guide vane (300) and the shell end cover (202).

7. A multiple stage impeller pump guide vane seal system as claimed in claim 2, wherein: The roughness of the flat portion d of the rear bending portion (305) is less than 3.2, the perpendicularity of the flat portion d reaches 7-9 levels, and the flatness level of the flat portion d is less than the perpendicularity level.

8. A multiple stage impeller pump guide vane seal system as claimed in claim 4, wherein: The angle between the inclined extension direction of the front bending portion (302) and the radial extension direction of the outer ring body (301) is 9°-45°.

9. A multiple stage impeller pump guide vane seal system as claimed in claim 4, wherein: The arc radius R2 of the arc-shaped transition portion b is greater than the arc radius R1 of the arc-shaped transition portion a.

10. A multiple stage impeller pump guide vane seal system as claimed in claim 4, wherein: The arc radius R1 of the arc-shaped transition portion a is 1.2mm≤R1≤2mm, and the arc radius R2 of the arc-shaped transition portion b is R2≥2.5mm.

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