Centrifugal pump

Abstract

The present application relates to a centrifugal pump, comprising a pump body assembly, the pump body assembly including a pump sleeve (22) and a plurality of impeller stage groups, each impeller stage group including: a support body assembly (300) and a diffuser cavity assembly (200), and an impeller assembly (100), the impeller assembly (100) including an impeller hub (110), an impeller (120), and an impeller seat (130), a wear-resistant accessory (150) defining a rotational engagement surface (152) being attached to the lower end surface of the impeller hub (110), the impeller axial support assembly (200 or 200') including an outer housing (210), an inner housing (220), and a diffuser (230) connected between the outer housing (210) and the inner housing (220), and a stationary support (250) attached to the inner housing (220), the stationary support (250) including a stationary engagement surface (254) engaging with the rotational engagement surface (152), such that the axial force of the impeller assembly (100) is transmitted to the inner housing (220), and then transmitted to the pump sleeve (22).

Description

Technical Field

[0001] This application relates to a centrifugal pump, particularly a multistage centrifugal pump for deep wells with high rotational speed and high head. Background Art

[0002] Centrifugal pumps for deep wells generally include a motor assembly and a pump body assembly containing impellers that are driven to rotate by a pump shaft. The rotational speed of the pump shaft of traditional centrifugal pumps is generally around 3000 rpm. If the head of the water output by the centrifugal pump is to reach 300 m, the height of the centrifugal pump may usually reach 3 m. Therefore, such deep well pumps are large in size and very heavy.

[0003] Most centrifugal pumps for deep wells are used for agricultural irrigation, and the operating environment is usually at depths ranging from 100 m to 500 m underground. In applications with harsh natural environments such as mountains, the operation is very inconvenient. In particular, just for the handling of the centrifugal pump, workers need to carry it manually to the top of the mountain, which may take several hours or even a day. Installing the large and heavy centrifugal pump into the bottom of a few hundred meters deep well and subsequent possible maintenance are very difficult. This greatly limits the application of centrifugal pumps.

[0004] In the process of improving the pump, in order to increase the head of the centrifugal pump, the method of increasing the diameter of the impeller is usually adopted, which further increases the volume and weight of the pump and exacerbates the above-mentioned inconvenience of the pump.

[0005] It is desired to simplify the structure of the pump. Summary of the Invention

[0006] The purpose of this application is to provide a centrifugal pump for deep wells with high power, high head but reduced volume and weight.

[0007] To this end, this application provides a centrifugal pump, including a pump sleeve and a plurality of impeller stage groups accommodated in the pump sleeve. Each impeller stage group includes: an impeller assembly driven to rotate by the pump shaft of the centrifugal pump, an impeller axial support assembly surrounding the lower half of the impeller assembly and providing an axial support function, and a support body assembly surrounding the upper half of the impeller assembly and providing support for it. The impeller axial support assembly and the support body assembly are mechanically connected together to form an impeller cavity for accommodating the impeller assembly, wherein:

[0008] The impeller assembly includes a hub defining a joint with the pump shaft, an impeller radially extending outward from the hub, and an impeller seat attached to the outer periphery of the impeller in the radial direction. An anti-wear accessory defining a rotational joint surface is attached to the lower end surface of the hub.

[0009] The impeller axial support assembly includes an outer housing mechanically connected to the support body assembly and attached to the pump sleeve, an inner housing surrounding a portion of the outer peripheral surface of the impeller hub, a guide vane connected between the outer housing and the inner housing, and a stationary support attached to the inner housing. The stationary support includes a stationary engagement surface that engages with the rotating engagement surface such that the axial force of the impeller assembly is transmitted to the inner housing and then to the pump sleeve.

[0010] In one embodiment, the anti-wear accessory is embedded in a groove formed in the lower end surface of the impeller hub or attached to at least a portion of the lower end surface of the impeller hub.

[0011] In one embodiment, the anti-wear accessory is a tungsten steel ring.

[0012] In one embodiment, the stationary support is directly or via an intermediate member attached to the inner housing.

[0013] In one embodiment, the stationary support is a ceramic ring.

[0014] In one embodiment, the impeller and the impeller seat define an impeller passage, and the outer housing, the inner housing, and the guide vane define a diversion passage that is in fluid communication with the impeller passage.

[0015] In one embodiment, the impeller includes a tapered portion that extends outward in the radial direction and upward in the axial direction starting from an axial position on the outer peripheral surface of the impeller hub, and blades that extend spirally from the lower surface of the tapered portion. The impeller seat is attached to the radial outer periphery of the blades.

[0016] In one embodiment, the angle between the lower surface and the axial direction is between 40° and 70°.

[0017] In one embodiment, the outer housing of the impeller axial support assembly is joined to the impeller seat through an intermediate ring. The intermediate ring includes an axially extending portion that extends substantially along the axial direction and a radially extending portion that extends radially outward from the axially extending portion. The axially extending portion is located radially inside the impeller seat and a first space is defined between them. The radially extending portion is located below the impeller seat and a second space is defined between them.

[0018] In one embodiment, an annular gap that allows impurities in the water to pass through is defined between the radially outermost end of the impeller seat of the impeller of each impeller stage group and the corresponding support body assembly.

[0019] In one embodiment, the plurality of impeller stage groups includes a first impeller stage group closest to the motor assembly of the centrifugal pump. The impeller axial support assembly corresponding to the first impeller stage group is an inlet seat assembly, and the support body assembly of the first impeller stage group is radially connected to the diffuser cavity assembly of the adjacent impeller stage group above it.

[0020] In one embodiment, the plurality of impeller stage groups includes other impeller stage groups above the first impeller stage group. The impeller axial support assembly corresponding to the other impeller stage groups is a diffuser cavity assembly.

[0021] In one embodiment, the pump shaft is a six-tooth pump shaft including six key teeth distributed in the circumferential direction.

[0022] In the centrifugal pump of the present application, the axial force borne by the impeller assembly in each impeller stage group is transmitted via the impeller to the diffuser cavity assembly, and then to the pump sleeve, without being superimposed on the adjacent impeller stage group below, thus avoiding the superposition of axial forces and reducing the resulting losses in pump efficiency and pump power. When achieving the same head, the height and weight of the pump are reduced by approximately two-thirds, greatly improving the application versatility and ease of use of the centrifugal pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The foregoing and other features, advantages, and benefits of the present application will be described in detail below with reference to the accompanying drawings and in conjunction with the exemplary embodiments of the present application. It should be understood that the drawings are not drawn to scale and are merely used to illustrate the principles of the present application, rather than to limit the present application to the illustrated embodiments. The components shown in the drawings do not necessarily exist in all embodiments of the present application, and components not shown in the drawings may exist in some embodiments of the present application.

[0024] Figure 1 is a longitudinal sectional view of an exemplary centrifugal pump of the present application;

[0025] Figure 2 is Figure 1 a partial exploded view of the centrifugal pump;

[0026] Figure 3 is Figure 1 an enlarged view of the impeller assembly and the diffuser cavity assembly of the second impeller stage group of the centrifugal pump;

[0027] Figure 4 is a cross-sectional view of the pump shaft of an exemplary centrifugal pump of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] The centrifugal pump of the present application will be described in detail below with reference to the accompanying drawings. Throughout the drawings, parts having the same or similar structures or functions have the same reference numerals.

[0029] Figure 1 and2 An axial sectional view and a partial exploded view of the centrifugal pump of the present application are respectively shown. Generally, the centrifugal pump includes a motor assembly 10 and a pump body assembly 20. The motor assembly 10 includes a motor housing and a motor, such as an electric motor, that is housed within the motor housing and can output a high rotational speed. An auxiliary system, such as a cooling system, that provides an auxiliary function for the operation of the motor is also provided within the motor housing. The pump body assembly 20 includes a pump sleeve 22 and a plurality of impeller stage groups housed within the pump sleeve 22. The output shaft of the motor drives the impellers of each impeller stage group in the centrifugal pump to rotate through the pump shaft 11 of the centrifugal pump. In the illustrated embodiment, the pump shaft 11 is a six-tooth pump shaft. Figure 4 A magnified cross-sectional view of the pump shaft 11 is shown, where the pump shaft 11 includes a body 111 and six convex portions 113 uniformly arranged on the outer peripheral surface of the body 111.

[0030] In the present application, for convenience of description, the direction in which the pump shaft 11 extends is defined as the axial direction, and the circumferential direction extends around the axial direction. The centrifugal pump of the present application is usually placed vertically during use, so the axial direction is also referred to as the vertical direction. The direction / end towards the motor assembly 10 in the axial direction is called the lower side / lower end, and the opposite direction / end is called the upper side / upper end. In a plane perpendicular to the axial direction, with the central axis of the pump shaft 11 that defines the axial direction as a reference, the direction from the pump sleeve 22 towards the central axis of the pump shaft 11 is called radially inward, and conversely, the direction from the central axis of the pump shaft 11 towards the pump sleeve 22 is called radially outward.

[0031] Refer again to Figure 1 and 2 , in the axial direction, from bottom to top, the pump body assembly 20 sequentially includes a water inlet section 30, an impeller section 50 composed of a plurality of impeller stage groups, and a water outlet section 40.

[0032] In the water inlet section 30, water inlet holes 32 are provided on the pump sleeve 22 and are distributed in the circumferential direction. And, in the water inlet section 30, a conical housing 34 is provided within the pump sleeve 22. The conical housing 34 is configured as an inverted cone that opens towards the motor assembly 10 and includes a central hole that allows the pump shaft 11 to pass through. A pump shaft connection portion that connects the pump shaft 11 to the output shaft of the motor assembly 10 and supports the pump shaft 11 is provided within a space 33 formed by the inner surface 37 of the conical housing 34 that faces the motor assembly 10. The opposite outer surface 39 of the conical housing 34 and the pump sleeve 22 define a water inlet space 35 that is in fluid communication with the water inlet holes 32 to receive water that enters from outside the centrifugal pump via the water inlet holes 32. According to the present application, the water inlet holes 32 include a plurality of water inlet hole groups that are spaced apart in the circumferential direction of the pump sleeve 22, and each water inlet hole group includes a plurality of water inlet holes that are densely distributed.

[0033] In the impeller section 50, five impeller stage groups B1 - B5 arranged in series in the axial direction are successively installed in the pump sleeve 22. Of course, the number of impeller stage groups of the centrifugal pump is not limited to five, but can be changed according to actual requirements. In this text, the impeller stage group adjacent to the water inlet section 30 and located at the bottom of the centrifugal pump is called the first impeller stage group, denoted by the reference mark B1; other impeller stage groups except the first impeller stage group are called other impeller stage groups, denoted by the reference marks B2 - B5.

[0034] Typically, in a centrifugal pump including multiple impeller stage groups B1 - B5 as shown in the figure, for other impeller stage groups B2 - B5 except the first impeller stage group B1 adjacent to the water inlet section 30, each impeller stage group includes an impeller assembly 100 driven by the pump shaft 11 to rotate together, a guide vane cavity assembly 200 surrounding the lower half of the impeller assembly 100 and providing an axial support function, and a support body assembly 300 surrounding the upper half of the impeller assembly 100 and providing support for it. The first impeller stage group B1, that is, the lowermost impeller stage group, has a slightly different structure because it is adjacent to and connected to the water inlet section 30 of the pump body assembly 20. The impeller assembly 100 of the first impeller stage group B1 also includes a support body assembly 300 surrounding its upper half. The difference is that the lower half of the impeller assembly 100 is axially supported by an inlet seat assembly 200' whose structure is slightly different from the above-mentioned guide vane cavity assembly 200.

[0035] Although the inlet seat assembly 200' that provides axial support for the impeller assembly 100 of the first impeller stage group B1 has a different structure from the guide vane cavity assembly 200 that provides axial support for the impeller assemblies 100 of other impeller stage groups B2 - B5, the interface structures between the inlet seat assembly 200' for the first impeller stage group B1 and the impeller assembly 100 and between the inlet seat assembly 200' and the support body assembly 300 are the same as the interface structures between the guide vane cavity assembly 200 for other impeller stage groups B2 - B5 and the impeller assembly 100 and between the guide vane cavity assembly 200 and the support body assembly 300. In view of this, in the description of this text, the inlet seat assembly 200' for the first impeller stage group B1 and the guide vane cavity assembly 200 for other impeller stage groups B2 - B5 are collectively referred to as the "impeller axial support assembly". That is to say, each impeller stage group B1 - B5 of the centrifugal pump of the present application includes an impeller assembly 100, a support body assembly 300, and an impeller axial support assembly 200 or 200'.

[0036] For each impeller stage group, its support body assembly 300 and impeller axial support assembly are mechanically connected together to jointly form an impeller cavity that houses and supports the impeller stage group 100. The support body assembly 300 of each impeller stage group is mechanically connected to the impeller axial support assembly 200 or 200' of the adjacent impeller stage group above it, so that the impeller stage groups are mechanically connected together. Similarly, for each impeller stage group, the impeller assembly 100 defines an impeller passage 125 (see Figure 3 ) through which water is allowed to flow, and the impeller axial support assembly 200 or 200' defines a guiding passage 225 ( Figure 3 ) that is in fluid communication with the impeller passage 125. The impeller passage 125 of each impeller stage group is in fluid communication with the guiding passage 225 of the adjacent impeller stage group above it, so as to form a continuous water flow passage in the entire impeller section 50. In other words, the impeller assemblies 100 and the impeller axial support assemblies 200 or 200' of all the impeller stage groups B1 - B5 jointly define this water flow passage.

[0037] In the water outlet section 40 located at the opposite end of the water inlet section 30, it includes the uppermost guide vane cavity assembly 410 connected to the support body assembly 300 of the last impeller stage group B5, a check valve assembly 420 installed on the guide vane cavity assembly 410, and an outlet seat assembly 430 connected to the pump sleeve 22 and defining an outlet 432 (as Figure 1 shown)

[0038] Figure 3 A cross-sectional view schematically showing the joint structure of the impeller assembly 100 and the impeller axial support assembly 200 in an enlarged form is taken with the second impeller stage group B2 as an example. Those skilled in the art should understand that the joint structure of the impeller assembly 100 and the impeller axial support assembly 200 described below for the second impeller stage group B2 is applicable to all other impeller stage groups of the centrifugal pump, including the first impeller stage group B1.

[0039] The structures of the impeller assemblies 100 and the support body assemblies 300 of all the impeller stage groups of the centrifugal pump are the same. The impeller assembly 100 mainly includes a hub 110, an impeller 120, and an impeller seat 130. The hub 110 is generally cylindrical and defines a shaft hole 112 that allows the pump shaft 11 of the centrifugal pump to pass through and engage with it. Usually, the hub 110 and the pump shaft 11 can be engaged via a key engagement method, Figure 3 and the keyway in the shaft hole 112 is schematically shown in

[0040] The impeller 120 includes a conical portion 124 that extends outward in the radial direction from the upper portion of the outer peripheral surface 114 of the hub 110, for example, outward from the axial position P and expanding upward in the axial direction, and blades 126 that extend spirally from the lower surface 123 of the conical portion 124. The impeller seat 130 is located radially outside the impeller 120 and is circumferentially attached to the impeller 120, specifically to the radial outer periphery or the free end of the blades 126. The impeller seat 130 includes an axial base 132 and an expansion portion 134 that extends radially outward and axially upward from the axial base 132. An impeller passage 125 allowing water to flow through is formed between the impeller 120 and the impeller seat 130. In an embodiment of the present application, the impeller 120 and the hub 110 are integrally formed, and the impeller seat 130 is attached to the outer periphery of the impeller 120 in any known manner in the art to rotate with the impeller 120. Those skilled in the art can understand that the hub 110, the impeller 120, and the impeller seat 130 can be separately formed and then attached together, or any two or all three of them can be integrally formed.

[0041] As described above, the blades 126 of the impeller 120 extend from the lower surface 123 of the conical portion 124. In one embodiment, the angle between the lower surface 123 and the horizontal plane is between 20° and 50°, in other words, the angle between the lower surface 123 and the central axis Z is between 40° and 70°.

[0042] An anti-wear accessory 150 is attached to the lower end surface of the hub 110. The anti-wear accessory 150 can be attached and fixed to the lower end surface of the hub 110 by any suitable means, including but not limited to interference fit, connection using fasteners, and any other known connection means in the art. In the illustrated embodiment, the anti-wear accessory 150 is embedded in a groove formed in the lower end surface of the hub 110. The lower end surface 152 of the anti-wear accessory 150 provides a rotating engagement surface for engaging with the impeller axial support assembly 200. In an embodiment not shown, it can be envisaged that the anti-wear accessory 150 can be attached to a part of the lower end surface of the hub 110 or cover the entire lower end surface of the hub 110.

[0043] The impeller axial support assembly 200 includes a housing 210 adapted to mechanically engage and be attached to the support body assembly 300 ( Figure 3 not shown in the figure) of the impeller stage group and attached to the pump sleeve 22, and an inner housing 220 that surrounds the lower half of the impeller stage group 100, specifically the lower part of the outer peripheral surface 114 of the hub 110. The guide vane 230 extends between the inner housing 220 and the outer housing 230, and together with the inner housing 220 and the outer housing 210, forms a guide vane passage 225 allowing water to flow through.

[0044] In the illustrated embodiment, the middleware 240 is fixedly attached to the inner housing 220. The stationary support base 250 that directly contacts and supports the impeller assembly 100 is attached to the middleware 240 and remains stationary during the operation of the centrifugal pump. The middleware 240 and the stationary support base 250 respectively define shaft holes 242 and 252 that allow the pump shaft to pass through. The stationary support base 250 includes an upper surface 254 that serves as a stationary engagement surface for contacting the rotating engagement surface provided by the lower end surface 152 of the above-mentioned wear-resistant accessory 150.

[0045] As Figure 3 shown, in the assembled state of the impeller assembly 100 and the impeller axial support assembly 200, the lower end surface 152 of the wear-resistant accessory 150 that rotates at a high speed with the impeller assembly 100 engages the upper surface 254 of the stationary ceramic support base 250. A dynamic seal engagement is formed between the contacting surfaces of the wear-resistant accessory 150 and the stationary support base 250, preventing water in the water flow channel from entering the pump shaft hole through the axial gap 270 between the inner housing 220 and the hub 110 of the impeller assembly 100. In one embodiment, the wear-resistant accessory 150 can be formed of tungsten steel material, and the stationary support base 250 can be formed of ceramic material. The selection of these two materials minimizes the frictional resistance between the relatively moving wear-resistant accessory 150 and the stationary support base 250. Preferably, as Figure 3 shown, there are notches 262 evenly distributed circumferentially on the upper end surface 254 of the stationary support base 250. The setting of these notches 262 avoids or greatly reduces the molecular binding force generated due to the formation of a vacuum between the high-speed rotating wear-resistant accessory 150 and the stationary stationary support base 250, greatly reducing the power loss of the centrifugal pump and improving the efficiency of the pump.

[0046] As shown in the figure, the outer housing 210 of the impeller axial support assembly 200 is joined to the axial base 132 of the impeller seat 130 of the impeller assembly 100 through an intermediate ring 280. The intermediate ring 280 includes an axially extending portion 282 that extends substantially along the axial direction and a radially extending portion 284 that extends radially outward therefrom transverse to the axially extending portion 282. A first space 292 is defined between the axially extending portion 282 and the axial base 132 of the impeller seat 130. A second space 294 is defined between the radially extending portion 284 and the axial base 132. The width of the first space 292 in the radial direction is smaller than the width of the second space 294 in the axial direction. The second space 294 can serve the function of pressure balance. Specifically, during the operation of the centrifugal pump, the water attempting to invade the water flow channel from the space radially outside the impeller seat 130 via the second space 294 and the first space 292 has its velocity greatly reduced after entering the second space 294, so that it will not continue to enter the first space 292, that is, most or even all of the water is blocked in the second space 294. At the same time, under the action of centrifugal force, the water in the second space 294 is thrown out, thereby forming an internal water pressure that counteracts the external water pressure, such that the impeller 120 does not bear the radial force generated by the water. In addition, the above water pressure balance also keeps the impeller assembly 100, specifically the impeller seat 130 and the outer housing 210, in a "sealed" state all the time, and the seal will not fail due to the high-speed rotation of the impeller.

[0047] In the non-operating state of the centrifugal pump, the impeller assembly 100 is assembled in the axial impeller cavity formed by the support body assembly 300 and the impeller axial support assembly 200. The lower end face 152 of the wear-resistant accessory 150 is in axial contact with the upper end face 254 of the stationary support 250, and the impeller axial support assembly 200 axially supports the impeller assembly 100 and the support body assembly 300.

[0048] When the centrifugal pump is in operation, the impeller assembly 100 is driven by the pump shaft 11 to rotate at a high speed within the axial impeller cavity. Water is sucked in from the diversion channel 225 defined by the impeller axial support assembly 200 under the action of the suction force generated by the rotation of the impeller 120, enters the impeller channel 125 of the impeller 120, and then is thrown into the diversion channel 225 of the next impeller stage group. At this time, the lower end face 152 of the wear-resistant accessory 150 rotating at a high speed with the impeller assembly 100 is axially in contact and sealingly engaged with the upper end face 254 of the stationary support member 250 that remains stationary. Any axial force received by the impeller assembly 120 is transmitted to the stationary support member 250 of the impeller axial support assembly 200, and then transmitted to the inner housing 220 and the outer housing 210. This transmission of the axial force causes friction to occur between the two mutually contacting end faces 152 and 254. To reduce the impact of this friction on the power and efficiency of the centrifugal pump, any surface treatment measures can be taken on the mutually contacting end faces 152 and 254. In one embodiment, an anti-friction coating can be applied to the end faces 152 and 254. In the illustrated embodiment, tungsten steel and ceramic materials are respectively selected to form the wear-resistant accessory 150 and the stationary support member 250, minimizing the frictional resistance and molecular bonding resistance generated on the two surfaces.

[0049] In addition, as shown in the figure, an annular gap 80 (see Figure 1 ) that allows impurities in the water, such as sediment, to settle downward is defined between the end 134a of the expansion portion 134 of the impeller seat 130 of the impeller assembly 100 and the support body assembly 300. Sediment in the water flowing in the impeller channel 125 enters the impurity collection space 90 jointly defined by the support body assembly 300 of the impeller stage group 100, the outer housing 220 of the impeller axial support assembly 200, and the impeller seat 130 after passing through the annular gap 80.

[0050] As described above, the axial force borne by the impeller assembly 100 in each impeller stage group is transmitted to the impeller axial support assembly 200 (or the inlet seat assembly for the first impeller stage group B1) through the axial engagement between the lower end face 152 of the wear-resistant accessory 150 and the upper end face 254 of the stationary support seat 250 of the impeller axial support assembly 200, and then transmitted to the pump sleeve 22, without being superimposed on the adjacent impeller stage group below. In this way, the axial force borne by the impeller stage group below will not increase, and no superposition of axial forces will occur. Such an arrangement reduces the pump power loss caused by the rotational friction generated by the superposition of the axial forces of the impeller assembly 100. On the other hand, performing corresponding surface treatment on the above-mentioned contact end faces or selecting specific materials can further reduce the lost pump power and improve the pump working efficiency.

[0051] The centrifugal pump of the present application adopts a motor structural component with an output speed as high as 12,000 or higher, and adopts the pump body component structure schematically shown in the figure. Only by configuring 5 impeller stage groups can a water output head of about 300 m be obtained. At this time, the total height of the centrifugal pump is only about 1 m. Even if the controller of the centrifugal pump is placed inside the centrifugal pump, the total height of the centrifugal pump is only about 1.5 m. Compared with the traditional centrifugal pump for deep wells, the height of the pump is shortened by one-half to two-thirds. The reduction in height means a significant reduction in the weight of the centrifugal pump. Such a structure makes the application of the deep well centrifugal pump more extensive, simpler, and easier.

[0052] Although the embodiments shown in the above reference figures describe the present invention, it will be apparent to those of ordinary skill in the art that other embodiments and examples can perform similar functions and / or achieve similar results. It is thus contemplated that all such equivalent embodiments and examples are within the spirit and scope of the present invention and are intended to be covered by the following non-limiting claims for all purposes.

Claims

1. A centrifugal pump, comprising a pump sleeve (22) and a plurality of impeller stage groups (B1 - B5) accommodated in the pump sleeve, each impeller stage group comprising: An impeller assembly (100) driven by a pump shaft (11) of a centrifugal pump to rotate therewith, an impeller axial support assembly (200 or 200') surrounding the lower half of the impeller assembly (100) and providing an axial support function, and a support body assembly (300) surrounding the upper half of the impeller assembly (100) and providing support thereto, wherein the impeller axial support assembly (200 or 200') and the support body assembly (300) are mechanically connected together to form an impeller chamber for accommodating the impeller assembly (100), wherein: The impeller assembly (100) includes an impeller hub (110) defining an engagement with the pump shaft (11), an impeller (120) radially extending outward from the impeller hub (110), and an impeller seat (130) attached to the outer periphery of the impeller (120). The impeller hub (110) is cylindrical, and an anti-wear accessory (150) defining a rotational engagement surface (152) is attached to the lower end surface of the impeller hub (110). The impeller axial support assembly (200 or 200') includes a housing body (210) mechanically connected to the support body assembly (300) and attached to the pump sleeve (22), an inner housing body (220) surrounding a part of the outer peripheral surface of the impeller hub (110), a guide vane (230) connected between the housing body (210) and the inner housing body (220), and a stationary support member (250) attached to the inner housing body (220). The stationary support member (250) includes a stationary engagement surface (254) engaging with the rotational engagement surface (152), such that the axial force of the impeller assembly (100) is transmitted to the inner housing body (220) and then to the pump sleeve (22). Wherein the housing body (210) of the impeller axial support assembly (200) is joined to the impeller seat (130) through an intermediate ring (280). The intermediate ring (280) includes an axially extending portion (282) extending substantially in the axial direction and a radially extending portion (284) radially extending outward therefrom transversely to the axially extending portion (282). The axially extending portion (282) is located radially inside the impeller seat (130) and a first space (292) is defined therebetween. The radially extending portion (284) is located below the impeller seat (130) and a second space (294) is defined therebetween.

2. The centrifugal pump according to claim 1, characterized in that, The anti-wear accessory (150) is embedded in a groove formed in the lower end surface of the impeller hub (110), or attached to at least a part of the lower end surface of the impeller hub (110).

3. The centrifugal pump according to claim 2, characterized in that The anti-wear accessory (150) is a tungsten steel ring.

4. The centrifugal pump according to claim 1, characterized in that, The stationary support member (250) is directly or via an intermediate member (240) attached to the inner housing body (220).

5. The centrifugal pump according to claim 4, characterized in that, The stationary support member (250) is a ceramic ring.

6. The centrifugal pump according to claim 1, characterized in that, The impeller (120) and the impeller seat (130) define an impeller passage (125), and the housing body (210), the inner housing body (220) and the guide vane (230) define a diversion passage (225) in fluid communication with the impeller passage (125).

7. The centrifugal pump according to claim 1, characterized in that, The impeller (120) includes a conical portion (124) that extends radially outward and axially upward starting from an axial position (P) on the outer peripheral surface (114) of the hub (110), and blades (126) that extend spirally from the lower surface (123) of the conical portion (124). The impeller seat (130) is attached to the radially outer periphery of the blades (126).

8. The centrifugal pump according to claim 7, characterized in that, The angle between the lower surface (123) and the axial direction is between 40° and 70°.

9. The centrifugal pump according to claim 1, characterized in that, An annular gap (80) that allows impurities in the water to pass through is defined between the radially outermost end (134a) of the impeller seat (130) of the impeller (120) of each impeller stage group and the corresponding support component (300).

10. The centrifugal pump according to any one of claims 1-8, characterized in that, The plurality of impeller stage groups includes a first impeller stage group (B1) closest to the motor assembly of the centrifugal pump. The impeller axial support assembly corresponding to the first impeller stage group (B1) is an inlet seat assembly (200′). The support body assembly (300) of the first impeller stage group (B1) is radially connected to the guide vane cavity assembly (200) of the adjacent impeller stage group above it.

11. The centrifugal pump according to claim 10, characterized in that, The plurality of impeller stage groups includes other impeller stage groups located above the first impeller stage group (B1). The impeller axial support assembly corresponding to the other impeller stage groups is a guide vane cavity assembly (200).

12. The centrifugal pump according to any one of claims 1-8, characterized in that, The pump shaft (11) is a six-tooth pump shaft including six key teeth (111) distributed in the circumferential direction.

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