Multi-stage impeller pump unit system

Abstract

The invention discloses a multi-stage impeller pump unit system, and belongs to the field of pump units. The front portion of each stage of guide vane assembly in the axial direction is provided with the arc-shaped abutting portion, the rear portion of each stage of guide vane assembly is provided with the plane abutting portion, the later stage of guide vane assembly abuts against the plane abutting portion of the rear portion of the previous stage of guide vane assembly for positioning through the arc-shaped abutting portion of the front portion, and the last stage of guide vane assembly abuts against the side wall plane of the front bearing seat for positioning through the plane abutting portion of the rear portion. A sealing area is formed below each arc-shaped abutting part, and a sealing piece is arranged in each sealing area. According to the invention, the mounting precision among the multi-stage guide vanes can be effectively guaranteed, and the sealing performance among the multi-stage guide vanes is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pump units, and more specifically, to a multi-stage impeller pump unit system. Background Art

[0002] The multi-stage impeller pump is a key device for high-pressure fluid transportation by connecting multiple impellers and diffusers in series. Its core advantage lies in step-by-step pressurization, enabling a relatively high head in a single pump while maintaining high hydraulic efficiency and operational stability. Compared with single-stage pumps, multi-stage pumps have a wider range of applications in fields such as petrochemical, power, water supply systems, and boiler feed water.

[0003] In the multi-stage pump structure, the main function of the diffuser 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 assembly sealing performance of multiple diffusers will directly affect the overall performance of the pump. If there is a deviation in the installation position of the diffuser, the single-stage installation error may accumulate step by step, easily leading to uneven fluid flow, generating periodic shocks, and then causing mechanical vibrations and abnormal noises. Under long-term operation, vibrations will accelerate the wear of key components such as bearings and mechanical seals, and may even cause fatigue fracture of the pump shaft, affecting the long-term stable operation of the pump. Moreover, it is easier to have poor sealing during multi-stage installation and cooperation, which will lead to inter-stage leakage, causing energy losses and reducing the overall efficiency of the pump. Therefore, ensuring the precise installation and sealing of the diffusers in the multi-stage impeller pump is particularly important for reducing vibrations and energy losses, and improving the overall performance and reliability of the pump. Summary of the Invention

[0004] 1. Technical Problems to be Solved by the Invention

[0005] Aiming at the situation in the prior art where the poor installation between multiple diffusers in a multi-stage impeller pump affects the overall performance of the pump, a multi-stage impeller pump unit system is proposed, which can effectively ensure the installation accuracy between multiple diffusers and improve the sealing performance between multiple diffusers, thereby facilitating the reduction of pump body vibrations and energy losses, and improving the overall performance and reliability of the pump.

[0006] 2. Technical Solutions

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

[0008] A multi-stage impeller pump unit system of the present invention includes a machine base, a pump casing, and a front bearing housing pressed between the machine base and the pump casing. A pump shaft is installed in the machine base and extends through the front bearing housing to the pump casing. Multi-stage guide vane assemblies are respectively sleeved on the pump shaft in the pump casing. The multi-stage guide vane assemblies include a first-stage guide vane and a last-stage guide vane. Each stage of the guide vane assembly has an arc-shaped abutting portion at the front in the axial direction and a flat abutting portion at the rear. The first-stage guide vane is abutted and positioned against the inner wall plane of the pump casing through the front arc-shaped abutting portion. The next-stage guide vane assembly is abutted and positioned against the flat abutting portion at the rear of the previous-stage guide vane assembly through the front arc-shaped abutting portion. The last-stage guide vane is abutted and positioned against the side wall plane of the front bearing housing through the flat abutting portion at the rear. And a sealing area is formed below each arc-shaped abutting portion, and a sealing member is provided in the sealing area.

[0009] Furthermore, specifically, each stage of the guide vane assembly has an outer ring body portion coaxially surrounding the outer periphery of the pump shaft. A guide vane fitting area is formed in the outer ring body portion for the front guide vane portion of the next-stage guide vane assembly to fit and embed. The front end of the outer ring body portion is bent inward to form a front bending portion. An arc-shaped transition portion a is formed between the front bending portion and the outer ring body portion. And the front bending portion extends obliquely inward in the radial direction from the outside to the direction gradually approaching the tail end of the outer ring body portion. The tail end of the outer ring body portion is formed with a rear bending portion bent inward. A flat portion d is formed on the outer wall surface of the rear bending portion in the radial direction.

[0010] When the multi-stage guide vane assemblies are assembled, the arc-shaped transition portion a of the front bending portion on the first-stage guide vane abuts against the inner wall plane of the pump casing for positioning. The arc-shaped transition portion a of the front bending portion on the next-stage guide vane abuts against the flat portion d of the rear bending portion on the previous-stage guide vane for positioning. The flat portion d of the rear bending portion on the last-stage guide vane abuts against the side wall plane of the front bearing housing for positioning.

[0011] Furthermore, an assembly ring portion coaxially distributed is also provided at the front end of the outer ring body portion. The front bending portion is connected between the outer ring body portion and the assembly ring portion. A front end cover extending radially is provided at the front end of the assembly ring portion. A through hole for the pump shaft to pass through is provided on the front end cover.

[0012] The bottom end of the rear bending portion is bent axially toward the direction close to the front bending portion to form an inner stop ring extending axially. An arc-shaped transition portion b is formed between the inner stop ring and the rear bending portion. So that when the multi-stage guide vane assemblies are assembled, a reduced-diameter sealing area is formed between the front bending portion of the next-stage guide vane assembly and the rear bending portion of the previous-stage guide vane assembly, and an internal and external coaxial clearance fit is maintained between the assembly ring portion of the next-stage guide vane assembly and the inner stop ring of the previous-stage guide vane assembly.

[0013] Furthermore, the pump housing includes an axially extending main housing, and the front end of the main housing has a radially extending housing end cover; a radially protruding end cover convex part is provided in the middle of the end cover, and an arc-shaped transition part c is formed between the end cover convex part and the end cover, and a variable-diameter sealing area is correspondingly formed between the arc-shaped transition part c and the front bending part of the first-stage guide vane; the arc-shaped transition part a of the front bending part on the first-stage guide vane abuts against the inner wall plane of the end cover, and the assembly ring part of the first-stage guide vane and the inner wall of the end cover convex part maintain an internal and external coaxial clearance fit.

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

[0015] The flat part d of the rear bending part on the last-stage guide vane abuts against the flat wall surface of the main body part, and the outer wall of the first convex ring part and the inner stop ring on the last-stage guide vane maintain an internal and external coaxial clearance fit.

[0016] Furthermore, guide vane parts are provided on the front end covers of the last-stage guide vanes, and the guide vane parts are fitted and embedded into the inner cavity of the outer ring body part of the previous-stage guide vane assembly;

[0017] The guide vane part includes a positive guide vane and a negative guide vane arranged in sequence 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 extending radially, and an axial extension part is provided on the outer edge of the front connecting wall; the axial extension part of the subsequent-stage guide vane assembly and the assembly ring part of the previous-stage guide vane assembly maintain an internal and external coaxial clearance fit.

[0018] Furthermore, a radially inward extending radial extension part is provided at the front end of the axial extension part, and a clearance fit is maintained between the radial extension part and the inner wall of the front end cover of the previous-stage guide vane assembly.

[0019] Furthermore, the roughness of the flat part d on the rear bending part is less than 3.2, and the perpendicularity of the flat part d reaches grade 7-9, and the flatness grade of the flat part d is less than the perpendicularity grade; or / and, the included angle between the inclined extension direction of the front bending part and the radial extension direction of the outer ring body part is 9°-45°.

[0020] Furthermore, the arc radius R2 of the arc-shaped transition part b between the rear bending part and the inner stop ring is greater than the arc radius R1 of the arc-shaped transition part a between the front bending part and the front end of the outer ring body part; or, the arc radius R1 of the arc-shaped transition part a between the front bending part and the front end of the outer ring body part is 1.2mm ≤ R1 < 2mm, and the arc radius R2 of the arc-shaped transition part b between the rear bending part and the inner stop ring is R2 ≥ 2.5mm; or / and, the arc radius R3 of the arc-shaped transition part c between the end cover and the end cover convex part is R3 ≥ 2.5mm.

[0021] Furthermore, the radial fit clearance between the assembly ring portion of the first-stage guide vane and the end cover convex portion of the pump casing, as well as the radial fit clearance between the assembly ring portion of the next-stage guide vane assembly and the inner stop collar of the previous-stage guide vane assembly, are both controlled to be 0.02 - 0.2 mm; the axial fit clearance between the radially extending portion of the next-stage guide vane assembly and the front end cover of the previous-stage guide vane assembly is ≥0.5 mm.

[0022] 3. Beneficial effects

[0023] Adopting the technical solution provided by the present invention, compared with the prior art, it has the following beneficial effects:

[0024] (1) In the pump unit system of the present invention, a contact positioning method of plane and arc surface is adopted between the first-stage guide vane and the inner wall of the pump casing, as well as between the front and rear stage guide vane assemblies, realizing a contact positioning method of surface and line, having a stronger self-adjusting function, forming an elastic line contact, improving the positioning accuracy, avoiding situations such as positioning inclination between multi-stage guide vane assemblies and the pump being unable to work properly, and forming a continuous sealing line, and a sealing ring is arranged in the formed sealing area to increase the sealing performance between the guide vane assemblies at all levels, reducing the head and efficiency losses caused by inter-stage leakage, and improving the energy efficiency level of the pump.

[0025] (2) In the pump unit system of the present invention, in addition to adopting the contact positioning of plane and arc surface for adjacent guide vane assemblies, the axial and radial clearance fits in other areas are additionally used for positioning and installation, which not only ensures the accuracy of positioning and installation, but also avoids the situation where double positioning cannot be installed, and at the same time reserves sufficient adjustment space for linear contact, and can reduce the fluid leakage amount, improving the head and efficiency. Description of the drawings

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

[0027] Figure 2 It is a schematic internal sectional view of the pump unit in the embodiment;

[0028] Figure 3 For Figure 2 The partial enlarged structural diagram at A in

[0029] Figure 4 For Figure 2 The partial axonometric view at A in

[0030] Figure 5 It is a schematic exploded view of the multi-stage guide vane cooperation in the embodiment;

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

[0032] Figure 7Partial enlarged schematic diagram of the mating state of the last-stage guide vane and the front bearing housing in the embodiment;

[0033] Figure 8 Schematic diagram of the structure of the intermediate guide vane in the embodiment;

[0034] Figure 9 For Figure 8 Schematic cross-sectional structure diagram of the intermediate guide vane;

[0035] Figure 10 Schematic diagram of the structure of the last-stage guide vane in the embodiment.

[0036] Explanation of the reference numerals in the schematic diagram:

[0037] 100, machine base; 101, main housing body; 102, pump shaft;

[0038] 200, pump casing; 201, main casing; 202, casing 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 part;

[0040] 301, outer ring body part; 302, front bending part; 303, assembly ring part; 304, front end cover; 305, rear bending part; 306, inner stop ring;

[0041] 311, return guide vane; 312, forward guide vane; 313, front connecting wall; 314, shaft extension part; 315, diameter extension part; 316, rear connecting wall; 321, water outlet;

[0042] 400, front bearing housing; 401, inner main body part; 402, shaft hole; 403, outer edge part; 404, first convex ring part; 405, main body part; 406, second convex ring part;

[0043] 500, impeller. Detailed implementation manners

[0044] To further understand the content of the present invention, the present invention will be described in detail with reference to the accompanying drawings.

[0045] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0046] In addition, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. The terms "first", "second", "third", and "fourth" should be understood in a broad sense, only for distinguishing the feature names and not indicating a specific sequential relationship. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] The present invention will be further described below in conjunction with embodiments.

[0048] Embodiment

[0049] Combined with Figures 1-10 As shown, a multi-stage impeller pump unit system of this embodiment includes a machine base 100, a pump casing 200, and a front bearing housing 400 pressed between the machine base 100 and the pump casing 200. A pump shaft 102 is installed in the machine base 100 and extends through the front bearing housing 400 and into the pump casing 200 in cooperation. Multi-stage guide vane assemblies in the pump casing 200 are respectively sleeved on the pump shaft 102. More specifically, the machine base 100 includes a main base body 101, and a motor assembly including the pump shaft 102, a rotor assembly, a stator assembly, etc. is installed inside the main base body 101. Multi-stage guide vane assemblies and multi-stage impellers 500 are installed in the pump casing 200. The impellers 500 are correspondingly and cooperatively installed in the inner regions of the guide vanes of the guide vane assemblies. The liquid discharged from the impellers 500 is discharged through the guide vanes and flows to the next-stage impellers 500 to achieve multi-stage pressurization of the water flow, and finally the liquid is guided to the high-pressure area and discharged.

[0050] In this embodiment, the multi-stage guide vane assemblies include a first-stage guide vane 300 and a last-stage guide vane 320, in order to Figure 3Taking the three-stage guide vane assembly shown as an example, it includes a first-stage guide vane 300, an intermediate guide vane 310, and a last-stage guide vane 320. When there are more than three stages, there are multiple groups of intermediate guide vanes 310. Each stage of the guide vane assembly has an arc-shaped abutting portion at the front in the axial direction and a flat abutting portion at the rear. The first-stage guide vane 300 is in contact and abutted for positioning with the inner wall plane of the pump casing 200 through the front arc-shaped abutting portion. The next-stage guide vane assembly is in contact and abutted for positioning with the flat abutting portion at the rear of the previous-stage guide vane assembly through the front arc-shaped abutting portion. The last-stage guide vane 320 is in contact and abutted for positioning with the side wall plane of the front bearing housing 400 through the rear flat abutting portion. And a sealing area is formed below each arc-shaped abutting portion, and a seal 210 is provided in this sealing area. Adopting the surface-line contact positioning of the arc-shaped abutting portion and the flat abutting portion helps to fully ensure the assembly accuracy of each stage of the guide vane assembly, ensure the coaxiality with the pump shaft 102, improve the assembly sealing performance, and at the same time utilize the further sealing area formed below the surface-line contact area to fully seal with the assembled seal 210. Specifically, an O-ring can be used.

[0051] More specifically, in combination with Figures 2-5 shown, the structure of the guide vane assembly is preferably adopted as follows: Each stage of the guide vane assembly has an outer ring body portion 301 coaxially surrounding the outer periphery of the pump shaft 102. A guide vane fitting area is formed inside the outer ring body portion 301 for the front guide vane portion 330 of the next-stage guide vane assembly to fit and embed. The front end of the outer ring body portion 301 is bent inward to form a front bending portion 302. An arc-shaped transition portion a is formed between the front bending portion 302 and the outer ring body portion 301. As shown by the identification in Figure 4 , and the front bending portion 302 extends obliquely in the direction gradually approaching the tail end of the outer ring body portion 301 from the outside to the inside along the radial direction. The tail end of the outer ring body portion 301 is formed with a rear bending portion 305 bent inward. A flat portion d is formed along the radial direction on the outer wall surface of the rear bending portion 305. When assembling multiple-stage guide vane assemblies, that is, using the arc-shaped transition portion a as the arc-shaped abutting portion and the flat portion d as the flat abutting portion, the arc-shaped transition portion a of the front bending portion 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 bending portion 302 on the next-stage guide vane abuts against the flat portion d of the rear bending portion 305 on the previous-stage guide vane for positioning. The flat portion d of the rear bending portion 305 on the last-stage guide vane 320 abuts against the side wall plane of the front bearing housing 400 for contact and positioning.

[0052] In the above - mentioned manner, between the first - stage guide vane 300 and the inner wall of the pump casing 200, as well as between the front - and - rear - stage guide vane assemblies, a contact - positioning method of a plane and an arc surface is adopted to achieve a contact - positioning method of a surface and a line. This can effectively reduce the requirements for the flatness of the flat part d of the rear - bending part 305 and the inner wall of the pump casing 200, as well as the parallelism requirement of the flat part d of the rear - bending part 305 relative to the arc - shaped transition part a on the front - bending part 302. Moreover, such a contact method has a stronger self - adjustment function. The line contact between the arc - shaped transition part a of the front - bending part 302 and the flat part d of the rear - bending part 305 allows the material near the contact area to undergo small elastic deformation, forming an "elastic line contact". Through deformation coordination of local unevenness, a continuous sealing line can be formed, increasing the sealing performance between the guide vane assemblies at all levels. At the same time, such a line - contact positioning method can also avoid the flatness error existing in the traditional surface contact. Especially, the cumulative error between multiple - stage guide vane assemblies becomes larger, resulting in situations such as positioning inclination between multiple - stage guide vane assemblies, poor coaxiality with the pump shaft 102, vibration and abnormal noise of the water pump, and even inability to work properly. This linear contact can further evenly distribute the stress along the contact line, avoiding stress concentration that affects the positioning accuracy due to the deformation of the contact surface.

[0053] Furthermore, in the guide vane assembly structure, an axially - distributed assembly ring part 303 is further provided at the front end of the outer ring body part 301. The front - bending part 302 is connected between the outer ring body part 301 and the assembly ring part 303, and the connection between the front - bending part 302 and the assembly ring part 303 is also a smooth transition connection. A radially - extending front end cover 304 is provided at the front end of the assembly ring part 303, and a through - hole for the pump shaft 102 to pass through is provided on the front end cover 304. The bottom end of the rear - bending part 305 is further bent axially towards the direction close to the front - bending part 302 to form an axially - extending inner stop ring 306, and an arc - shaped transition part b is formed between the inner stop ring 306 and the rear - bending part 305. When assembling multiple - stage guide vane assemblies, a variable - diameter sealing area that approaches a triangle in cross - section is jointly formed by the rear - bending part 305 and the inner stop ring 306 of the previous stage and the front - bending part 302 and the assembly ring part 303 of the next stage, that is, the inner - region space increases radially inward, having an appropriate sealing - ring installation space. And when the two - stage guide vane assemblies are in line - contact abutment positioning, effective extrusion of the sealing ring can be formed, so as to improve the sealing performance between the guide vane assemblies, further reducing the head and efficiency losses caused by inter - stage leakage and improving the energy - efficiency level of the water pump. In practice, the assembly ring part 303 of the next - stage guide vane assembly corresponds to the inner stop ring 306 of the previous - stage guide vane assembly in position and maintains an internal - and - external coaxial clearance fit. Preferably, the radial fit clearance is 0.02 - 0.2 mm in practice. The inner stop ring 306 of the previous - stage guide vane assembly is used to form radial positioning of the next - stage guide vane assembly, ensuring both the accuracy of positioning and installation and avoiding the situation of impossible installation due to double - positioning. At the same time, it also reserves sufficient adjustment space for linear contact and can reduce the leakage amount of fluid from the high - pressure area to the low - pressure area in the guide vane, improving the head and efficiency.

[0054] Specifically, in practice, for the arc transition part a between the front bending part 302 and the front end of the outer ring body part 301, it is preferably controlled that the arc radius R1 is between 1.2 mm and 2 mm. The arc surface can be formed by stretch forming without secondary processing. And preferably, 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°, such as 9°, 15°, 30°, 45°, etc., to avoid bending rupture and to form a sufficient variable-diameter sealing area with a cross-section approaching a triangle. For the rear bending part 305 and the tail end of the outer ring body part 301, stretch forming is also used for smooth arc transition, and a flat part d is formed by secondary processing on the outer wall surface of the rear bending part 305 extending radially. And preferably, the roughness of the flat part d is controlled to be less than 3.2, the perpendicularity of the flat part d meets the requirements of grade 7-9, and the flatness grade of the flat part d is lower than the perpendicularity grade, such as the flatness is grade 7 and the perpendicularity is grade 8 or 9, etc., to ensure that when the last-stage guide vane 320 is installed, the flat part d is kept in close contact and positioned with the side wall plane of the front bearing seat 400 and has strong sealing performance. A large arc transition is adopted between the rear bending part 305 and the inner stop ring 306, and 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 bending part 302 and the outer ring body part 301. Specifically, it is controlled that R2≥2.5 mm to facilitate the formation of a variable-diameter sealing area.

[0055] To achieve the line contact fit between the first-stage guide vane 300 and the pump casing 200 and the formation of a variable-diameter sealing area, in practice, it can be preferably designed that the pump casing 200 includes an axially extending main casing 201, and the front end of the main casing 201 has a radially extending shell end cover 202; and a axially protruding end cover convex part 203 is provided in the middle of the shell end cover 202, and an arc transition part c is also formed between the end cover convex part 203 and the shell end cover 202. Similarly, the arc radius R3 of the arc transition part c is controlled to be R3≥2.5 mm, and a variable-diameter sealing area is correspondingly formed between the arc transition part c and the front bending part 302 of the first-stage guide vane 300; the arc transition part a of the front bending part 302 on 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 convex part 203 are kept in coaxial clearance fit inside and outside. Similarly, the radial fit clearance is preferably 0.02-0.2 mm to avoid the situation of double positioning and inability to install, to reserve sufficient adjustment space for linear contact and to reduce fluid leakage.

[0056] Combined with Figures 3-6As shown, further, the front bearing housing 400 can be designed as follows. It includes a radially extending main body portion 405. A shaft hole 402 for the pump shaft 102 to pass through is provided in the middle of the main body portion 405. A first convex ring portion 404 protruding axially is provided on the wall surface of the main body portion 405 facing the last-stage guide vane 320. The flat portion d of the rear bent portion 305 on the last-stage guide vane 320 abuts and contacts the flat wall surface of the main body portion 405 for positioning. And the outer wall of the first convex ring portion 404 and the inner stop ring 306 on the last-stage guide vane 320 maintain an internal and external coaxial clearance fit. Preferably, the radial fit clearance is 0.02 - 0.2 mm. The cooperation between the main body portion 405 of the front bearing housing 400 and the rear bent portion 305 on the last-stage guide vane 320 realizes the plane abutting and positioning in the axial direction. The cooperation between the first convex ring portion 404 of the front bearing housing 400 and the inner stop ring 306 of the last-stage guide vane 320 realizes the positioning in the radial direction.

[0057] More specifically, in combination with Figure 5 and Figure 6 , the outer edge of the main body portion 405 of the front bearing housing 400 is the outer edge portion 403. An axially protruding second convex ring portion 406 is provided on the inner side surface of the outer edge portion 403 facing the pump casing 200. The main casing 201 of the pump casing 200 is sleeved on the outer circumference of the second convex ring portion 406 and abuts and presses the outer edge portion 403 to press the front bearing housing 400 between the pump casing 200 and the main seat body 101 of the machine base 100. And a surrounding sealing ring can be provided between the main casing 201 and the second convex ring portion 406 for sealing. The first convex ring portion 404 inside the main body portion 405 and the second convex ring portion 406 are coaxially distributed. And a radially extending inner main body portion 401 is formed between the annular ends of the first convex ring portion 404. The shaft hole 402 is opened at the center of the inner main body portion 401.

[0058] In this embodiment, further, a guide vane portion 330 is also provided on the front end covers 304 of the intermediate guide vane 310 and the last-stage guide vane 320. The guide vane portion 330 is fitted and embedded in the inner cavity of the outer ring body portion 301 of the previous-stage guide vane assembly. And the first-stage guide vane 300 does not need to be provided with the guide vane portion 330. And a plurality of outlet holes 321 are provided around the outer ring body portion 301 of the last-stage guide vane 320 to facilitate the flow of the pressurized liquid to the high-pressure area for discharge. Specifically, in combination with Figures 8-10As shown in the figure, the guide vane part 330 includes a stay vane 312 and a return vane 311 arranged in sequence along the water flow direction. The return vane 311 is fixed on the front end cover 304. The front end of the return vane 311 is connected to the stay vane 312 through a rear connection wall 316. The front end of the stay vane 312 is provided with a front connection wall 313 extending radially. The outer edge of the front connection wall 313 is provided with an axial extension part 314. When assembling multiple-stage guide vane assemblies, an internal and external coaxial clearance fit is maintained between the axial extension part 314 of the latter-stage guide vane assembly and the inner wall of the assembly ring part 303 of the former-stage guide vane assembly. The specific radial clearance is 0.02 - 0.2 mm. Further, the front end of the axial extension part 314 is provided with a radial extension part 315 extending radially inward. A clearance fit is maintained between the radial extension part 315 of the next-stage guide vane assembly and the inner wall of the front end cover 304 of the former-stage guide vane assembly. The specific axial clearance is that the fit clearance ≥ 0.5 mm to ensure that the axial extension part 314 does not contact the front end cover 304 of the former-stage guide vane assembly and avoid the situation of double positioning at both ends of the same-stage guide vane assembly, which affects the installation.

[0059] In the multi-stage impeller pump unit system of this embodiment, by using the limit 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 housing 400, the installation accuracy of the multi-stage guide vane assemblies can be effectively improved, the coaxial installation with the pump shaft 102 can be ensured, the sealing performance can be improved, and the overall performance of the pump unit can be comprehensively enhanced.

[0060] The protection scope of the present invention is only defined by the claims. Benefiting from the teachings of the present invention, those skilled in the art can easily recognize that alternative structures of the structures disclosed in the present invention can be used as feasible alternative embodiments, and the embodiments disclosed in the present invention can be combined to generate new embodiments, which also fall within the scope of the appended claims.

Claims

1. A multi-stage impeller pump unit system, comprising a machine base (100), a pump casing (200), and a front bearing seat (400) pressed between the machine base (100) and the pump casing (200); a pump shaft (102) is installed in the machine base (100) and cooperates to pass through the front bearing seat (400) and extend into the pump casing (200); a multi-stage guide vane assembly in the pump casing (200) is respectively sleeved on the pump shaft (102), characterized in that: The multi-stage guide vane assembly comprises a first-stage guide vane (300) and a last-stage guide vane (320), each stage guide vane assembly having an arc-shaped abutment portion at the front portion along the axial direction and a plane abutment portion at the rear portion, the first-stage guide vane (300) being positioned by abutting against the plane of the inner wall of the pump casing (200) through the front arc-shaped abutment portion, the last-stage guide vane assembly being positioned by abutting against the plane of the rear portion of the first-stage guide vane assembly through the front arc-shaped abutment portion, the last-stage guide vane (320) being positioned by abutting against the plane of the side wall of the front bearing seat (400) through the rear plane abutment portion, and a sealing area being formed below each arc-shaped abutment portion, and a sealing member (210) being provided in the sealing area.

2. A multi-stage impeller pump unit system according to claim 1, characterized in that: Each stage of the guide vane assembly has an outer ring body (301) coaxially surrounding the outer circumference of the pump shaft (102), and a guide vane fitting area is formed in the outer ring body (301) for the front end guide vane part (330) of the next stage of the guide vane assembly to fit and embed; The front end of the outer ring body (301) is bent inward to form a front bending portion (302), an arc-shaped transition portion a is formed between the front bending portion (302) and the outer ring body (301), and the front bending portion (302) extends obliquely from the outside to the inside in a direction gradually approaching the tail end of the outer ring body (301) along the radial direction; the tail end of the outer ring body (301) is formed with a rear bending portion (305) bent inward, and a plane portion d is formed on the outer wall surface of the rear bending portion (305) along the radial direction; When assembling the multi-stage guide vane assembly, the arc-shaped transition portion a of the front bend portion (302) on the first-stage guide vane (300) is positioned against the inner wall plane of the pump casing (200), the arc-shaped transition portion a on the second-stage guide vane assembly is positioned against the flat portion d on the first-stage guide vane assembly, and the flat portion d of the rear bend portion (305) on the last-stage guide vane (320) is positioned against the side wall plane of the front bearing seat (400).

3. A multi-stage impeller pump unit system according to claim 2, characterized in that: The front end of the outer ring body (301) is also provided with a coaxially distributed assembly ring portion (303), the front bent portion (302) is connected between the outer ring body (301) and the assembly ring portion (303), the front end of the assembly ring portion (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) is bent axially in a direction close to the front bend (302) to form an inner stop ring (306) extending axially, and an arc-shaped transition portion b is formed between the inner stop ring (306) and the rear bend (305); when the multi-stage guide vane assembly is assembled, a variable diameter sealing area is formed between the front bend (302) of the next-stage guide vane assembly and the rear bend (305) of the previous-stage guide vane assembly, and the assembly ring (303) of the next-stage guide vane assembly and the inner stop ring (306) of the previous-stage guide vane assembly maintain an inner and outer coaxial clearance fit.

4. A multi-stage impeller pump unit system according to claim 3, characterized in that: The pump casing (200) comprises an axially extending main casing (201), the front end of the main casing (201) is provided with a radially extending casing end cover (202); an axially protruding end cover convex portion (203) is provided in the middle of the casing end cover (202), and an arc-shaped transition portion c is formed between the end cover convex portion (203) and the casing end cover (202), and a variable diameter sealing area is formed between the arc-shaped transition portion c and the front bending portion (302) of the first-stage guide vane (300); the arc-shaped transition portion a of the front bending portion (302) on the first-stage guide vane (300) is against the inner wall plane of the casing end cover (202), and the assembly ring portion (303) of the first-stage guide vane (300) and the inner wall of the end cover convex portion (203) maintain an inner and outer coaxial clearance fit.

5. A multi-stage impeller pump unit system according to claim 3, characterized in that: The front bearing seat (400) comprises a main body (405) extending radially, a shaft hole (402) for the pump shaft (102) to pass through is provided in the middle of the main body (405), and a first convex ring portion (404) protruding in the axial direction is provided on the wall surface of the main body (405) facing the last-stage guide vane (320); The plane portion d of the rear bent portion (305) on the last-stage guide vane (320) is in contact with the plane wall surface of the main body (405), and the outer wall of the first convex ring portion (404) and the inner stop ring (306) on the last-stage guide vane (320) maintain an inner and outer coaxial clearance fit.

6. A multi-stage impeller pump unit system according to claim 2, characterized in that: A guide vane portion (330) is provided on the front end cover (304) of the last-stage guide vane (320), and the guide vane portion (330) is fitted and embedded in the inner cavity of the outer ring body (301) of the previous-stage guide vane assembly; The guide vane portion (330) comprises a positive guide vane (312) and a reverse guide vane (311) which are sequentially arranged along the water flow direction; the reverse guide vane (311) is fixed on the front end cover (304); a front connecting wall (313) extending in the radial direction is provided at the front end of the positive guide vane (312); an axial extension portion (314) extending in the axial direction is provided at the outer edge of the front connecting wall (313); the axial extension portion (314) of the rear-stage guide vane assembly and the assembly ring portion (303) of the front-stage guide vane assembly maintain an inner and outer coaxial clearance fit.

7. A multi-stage impeller pump unit system according to claim 6, characterized in that: A radial extension portion (315) extending radially inward is provided at the front end of the shaft extension portion (314), and a clearance fit is maintained between the radial extension portion (315) and the inner wall of the front end cover (304) of the previous stage guide vane assembly.

8. A multi-stage impeller pump unit system according to claim 2, characterized in that: The roughness of the plane portion d on the rear bending portion (305) is less than 3.2, and the verticality of the plane portion d reaches level 7-9, and the flatness level of the plane portion d is less than the verticality level; or / and, 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 multi-stage impeller pump unit system according to claim 4, characterized in that: The arc radius R2 of the arc-shaped transition portion b between the rear bend portion (305) and the inner stop ring (306) is greater than the arc radius R1 of the arc-shaped transition portion a between the front bend portion (302) and the front end of the outer ring body (301); or, the arc radius R1 of the arc-shaped transition portion a between the front bend portion (302) and the front end of the outer ring body (301) is 1.2mm≤R1≤2mm, and the arc radius R2 of the arc-shaped transition portion b between the rear bend portion (305) and the inner stop ring (306) is ≥2.5mm; or / and, the arc radius R3 of the arc-shaped transition portion c between the shell end cover (202) and the end cover protrusion (203) is ≥2.5mm.

10. A multi-stage impeller pump unit system according to claim 4, characterized in that: The radial fit clearance between the assembly ring (303) of the first-stage guide vane (300) and the end cover convex portion (203) of the pump housing (200), and the radial fit clearance between the assembly ring (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 0.02-0.2 mm; the axial fit clearance between the radial extension portion (315) of the next-stage guide vane assembly and the front end cover (304) of the previous-stage guide vane assembly is ≥0.5 mm.

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