Multi-stage centrifugal pump flow guide body supporting structure and multi-stage centrifugal pump

Abstract

A multi-stage centrifugal pump flow guide body supporting structure and a multi-stage centrifugal pump. A guide vane (103) is provided in each flow guide body (1), a supporting shaft sleeve (14) of a pump shaft (3) is fixedly mounted in the middles of the guide vanes (103), and each flow guide body (1) is the flow guide body (1) configured to share a central axis with the supporting shaft sleeve (14). During the rotation of the pump shaft (3), radial supporting is provided by means of the supporting shaft sleeve (14), thereby improving the strength of radial supporting for the pump shaft (3). In addition, each flow guide body (1) is configured to share the central axis with the supporting shaft sleeve (14), that is, the central axis of each flow guide body (1) is the central axis of the supporting shaft sleeve (14), such that when multiple stages of flow guide bodies (1) in the multi-stage centrifugal pump are arranged stage by stage, the central axis of the supporting shaft sleeve (14) is used for fixed-axis machining, and thus the center and the circumference of each flow guide body (1) are located by taking the center of the supporting shaft sleeve (14) as the central axis, thereby improving the accuracy of locating the central axis of the flow guide body (1), reducing the center deviation of a series arrangement of different flow guide bodies (1), and improving the rotation stability of the multi-stage centrifugal pump.

Description

Multistage centrifugal pump guide body support structure and multistage centrifugal pump

[0001] This application claims priority to the above-mentioned Chinese patent application filed with the China Patent Office on September 13, 2023, with application number 202322524503.6 and utility model name “Multi-stage centrifugal pump guide body support structure and multi-stage centrifugal pump”, the entire contents of which are incorporated by reference into the above-mentioned application. Technical Field

[0002] The utility model relates to the technical field of multi-stage centrifugal pumps, and more specifically, to a multi-stage centrifugal pump guide body support structure and the multi-stage centrifugal pump. Background Art

[0003] A multistage centrifugal pump is a pump that integrates a motor and pump body, immersed in groundwater wells to pump and deliver water. It is widely used in agricultural irrigation and drainage, industrial and mining enterprises, urban water supply and drainage, and sewage treatment. Multistage centrifugal pumps pump water through the high-speed rotation of the pump impeller, drawing groundwater through the diverter body at high speed. During impeller rotation, the liquid flow can easily cause radial oscillation of the pump shaft. Contact between the pump shaft and the diverter body through the pump shaft hole can cause wear on the diverter body and pump shaft after prolonged operation, affecting the radial support stability of both.

[0004] A multi-stage centrifugal pump is provided with a multi-stage guide body arranged in series. Due to processing errors, the serial structure of the guide body can easily cause coaxiality differences between multiple guide bodies and the pump shaft, which also aggravates the radial swing of the pump shaft and also affects the rotational stability of the pump shaft in the guide body.

[0005] Therefore, how to improve the support stability of the guide body and the pump shaft during the water pumping process is an urgent problem to be solved by those skilled in the art.

[0006] It should be pointed out here that the technical content provided in this section is intended to help those skilled in the art understand the present invention, and does not necessarily constitute prior art.

[0007] Utility Model Content

[0008] In view of this, the purpose of the present invention is to provide a multi-stage centrifugal pump guide body support structure to improve the support stability of the guide body and the pump shaft during the water pumping process; the present invention also provides a multi-stage centrifugal pump.

[0009] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0010] A multi-stage centrifugal pump guide body support structure, wherein a guide vane is provided in the guide body, a pump shaft support sleeve is fixedly installed in the middle of the guide vane, and the guide body is configured to share a central axis with the support sleeve.

[0011] Preferably, in the above-mentioned multi-stage centrifugal pump guide body support structure, a positioning ring is mounted on the outer periphery of the guide body, and the positioning ring is processed into a positioning ring whose outer periphery is coaxial with the support sleeve.

[0012] Preferably, in the above-mentioned multi-stage centrifugal pump guide body support structure, the guide body includes a guide body upper cover and a guide body lower cover spliced ​​together along the axial direction, and the axial ends of the positioning ring are respectively mounted on the guide body upper cover and the guide body lower cover.

[0013] Preferably, in the above-mentioned multi-stage centrifugal pump body guide support structure, the positioning ring is installed through one end of the body guide upper cover, and the lower end of the body guide lower cover is provided with a limiting step for limiting the installation position of the positioning ring.

[0014] Preferably, in the above-mentioned multi-stage centrifugal pump guide body support structure, the supporting sleeve is a ceramic sleeve, a sleeve mounting hole is provided in the middle of the guide vane, and positioning structures for positioning the sleeve mounting hole and the mounting end surface of the ceramic sleeve are provided.

[0015] Preferably, in the above-mentioned multi-stage centrifugal pump guide body support structure, the positioning ring is a stainless steel positioning ring, and the stainless steel positioning ring is processed so that the outer peripheral surface is coaxially arranged with the support sleeve.

[0016] Preferably, in the above-mentioned guide vane support structure, a plane bearing is provided on the water outlet side of the guide vane, and the plane bearing includes a supporting side and an embedded side, and the outer diameter of the embedded side is larger than the outer diameter of the supporting side;

[0017] The inner ring of the guide vane is provided with an embedding groove for embedding the plane bearing, and the ceramic sleeve is in abutment with the plane bearing.

[0018] Preferably, in the above-mentioned multi-stage centrifugal pump guide body support structure, the inner wall surface of the bearing mounting hole has an inwardly protruding limiting protrusion, and the outer wall surface of the ceramic sleeve is provided with a clamping groove that cooperates with the limiting protrusion;

[0019] The limiting protrusions and the clamping grooves include multiple groups surrounding the circumference of the bearing mounting hole.

[0020] A multi-stage centrifugal pump comprises a pump body and a pump shaft, wherein the pump shaft is provided with multiple groups of impellers and guide bodies arranged in stages, the guide body having a multi-stage centrifugal pump guide body support structure as described in any one of the above items, and the inner ring of the ceramic bearing is provided with a rotor bearing sleeved on the pump shaft.

[0021] Preferably, in the above-mentioned multi-stage centrifugal pump, there is a first fitting clearance between the rotor bearing and the pump shaft, and there is a second fitting clearance between the support sleeve and the rotor bearing, and the first fitting clearance is larger than the second fitting clearance.

[0022] Preferably, in the above multi-stage centrifugal pump, the fitting tolerance of the second fitting clearance is 0.04-0.06

[0023] The utility model provides a multi-stage centrifugal pump guide body support structure, wherein a guide vane is provided in the guide body, a pump shaft support sleeve is fixedly installed in the middle of the guide vane, and the guide body is configured to share a central axis with the support sleeve. When the multi-stage centrifugal pump pumps liquid, the liquid is lifted by the guide body and then pumped out. The guide vane is provided in the guide body, and during the lifting process, the liquid circulates through the guide vane's guide. A support sleeve fixedly installed in the middle of the guide vane supports the pump shaft. During the rotation of the pump shaft, the support sleeve provides radial support, thereby improving the radial support strength of the pump shaft. At the same time, the guide body is configured to share a central axis with the support sleeve, and the central axis of the guide body is the central axis of the support sleeve. When the multi-stage guide bodies in the multi-stage centrifugal pump are arranged step by step, the central axis of the support sleeve is fixedly processed, so that when the guide body is positioned at the center and the periphery, the center of the support sleeve is used as the central axis. This improves the positioning accuracy of the central axis of the guide body, reduces the center deviation of different guide bodies arranged in series, and improves the rotation stability of the multi-stage centrifugal pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0025] FIG1 is a cross-sectional view of a multi-stage centrifugal pump guide body support structure provided by the present invention;

[0026] FIG2 is a schematic diagram of the cross-sectional structure of the flow guide body in FIG1 ;

[0027] FIG3 is a schematic diagram of the structure of the ceramic sleeve in FIG1 ;

[0028] FIG4 is a cross-sectional view of the guide body support structure of the multi-stage centrifugal pump in FIG1 taken along the AA direction. DETAILED DESCRIPTION

[0029] The present invention will be described below based on embodiments, but the present invention is not limited to these embodiments.

[0030] As shown

[0031] 1-3, FIG1 is a cross-sectional view of the guide body support structure of the multi-stage centrifugal pump provided by the present invention; FIG2 is a schematic diagram of the cross-sectional structure of the guide body in FIG1; FIG3 is a schematic diagram of the ceramic sleeve structure in FIG1.

[0032] Since the impellers 2 and the guide bodies 1 in the multi-stage centrifugal pump are multiple groups of structures arranged in series, adjacent impellers 2 and guide bodies 1 are arranged continuously to achieve continuous water pumping along the axial direction of the multi-stage centrifugal pump. In the following, for the supporting structure of the impellers 2 and the guide bodies 1, the same parts will be shown with the same reference numerals.

[0033] This embodiment provides a guide body support structure for a multi-stage centrifugal pump. Guide vanes 103 are disposed within the guide body 1. A pump shaft support sleeve 14 is fixedly mounted in the middle of the guide vanes 103. The guide body 1 is configured to share a central axis with the support sleeve 14. When the multi-stage centrifugal pump pumps liquid, the liquid is lifted by the guide body 1 and then pumped out. The guide vanes 103 are disposed within the guide body 1. During the lifting process, the liquid circulates through the guide vanes 103. A support sleeve 14, which supports the pump shaft 3, is fixedly mounted in the middle of the guide vanes 103. During rotation, the pump shaft 3 is radially supported by the support sleeve 14, thereby improving the radial support strength of the pump shaft 3. At the same time, the guide body 1 is set to share a central axis with the support sleeve 14, and the central axis of the guide body 1 is the central axis of the support sleeve 14. When the multi-stage guide bodies 1 in the multi-stage centrifugal pump are arranged step by step, the central axis of the support sleeve 14 is fixed-axis processed, so that when the guide body 1 is positioned at the center and the periphery, the center of the support sleeve 14 is used as the central axis, which improves the positioning accuracy of the central axis of the guide body 1, reduces the center deviation of different guide bodies 1 arranged in series, and improves the rotation stability of the multi-stage centrifugal pump.

[0034] The guide body 1 is a plastic part, and the guide body structure is obtained by injection molding. The existing guide body 1 is obtained by injection molding. Guide vanes 103 are arranged inside the guide body 1, and the pump shaft passes through the inner ring of the guide vane 103. The guide body 1 is a cylindrical structure. The multi-stage guide body 1 is installed in the pump barrel 4 of the multi-stage centrifugal pump after assembly. Due to the dimensional deviation of the injection molding of the guide body 1, the multi-stage guide body 1 is installed in series in the pump barrel 4, and the pump shaft 3 passes through the guide vanes 103 in the multi-stage guide body 1. The pump shaft passes through the holes of the multi-stage guide vanes 103. After the guide bodies 1 are connected in series, the center axis will be offset, affecting the coaxiality of the pump shaft 3 in the pump shaft through the holes in the guide vanes 103. After the multi-stage guide body 1 is connected in series, the outer peripheral surface will also produce coaxiality deviation, which will affect the coaxiality of the pump shaft through hole of the multi-stage guide body 1 during the pumping process of the multi-stage centrifugal pump. The processing error of the outer peripheral surface of the multi-stage guide body 1 will also be transmitted to the pump shaft through hole, further affecting the coaxiality of the pump shaft through hole, causing radial deviation of the pump shaft 3, contact with the pump shaft through hole of the guide vane, and causing wear.

[0035] A support sleeve 14 is provided in the middle of the guide body 1, and is coaxially arranged with the guide body 1. Specifically, the central axis of the support sleeve 14 serves as the center of the guide body 1, and the guide body 1 is coaxially arranged with the support sleeve 14. The central axis of the support sleeve 14 is the central axis of the pump shaft passage hole of the guide vane 103. After the multi-stage guide bodies 1 are arranged in series, the support sleeve 14 and the pump shaft 3 are coaxially arranged. At the same time, the outer peripheral surface of the guide body 1 is machined with the central axis of the support sleeve 14 as the central axis. The central pump shaft passage hole of the multi-stage guide body 1 and the outer peripheral surface of the guide body 1 share the same central axis. This improves the coaxiality of the assembled multi-stage guide bodies in the multi-stage centrifugal pump, thereby improving the operating stability of the multi-stage centrifugal pump.

[0036] Furthermore, the outer periphery of the guide body 1 is enclosed by a positioning ring 104, which is machined so that its outer periphery is coaxial with the support sleeve 14. Positioning ring 104 is made of stainless steel and machined so that its outer periphery is coaxial with the support sleeve 14. Guide vanes 103 are located within the guide body 1, which also houses the liquid flow channels of the multi-stage centrifugal pump. The outer periphery stability of the guide body 1 determines its structural strength.

[0037] A stainless steel locating ring 103 is mounted on the outer periphery of the diverter body 1, and a stainless steel locating ring 104 is mounted on the outer ring of the diverter body structure. The inner ring of the stainless steel locating ring is tightly fitted to the diverter body 1. Since the stainless steel locating ring is mounted on the outer periphery of the diverter body 1, its inherent structural stability is ensured. By adding the stainless steel locating ring, the center axis of the support sleeve 14 serves as the center axis of the diverter body 1 and also as the machining center axis of the stainless steel locating ring. If the center axis of the diverter body is offset relative to the center axis of the stainless steel locating ring, the stainless steel locating ring can be rotated and cut so that the center axis of the stainless steel locating ring is the same as the center axis of the support sleeve. This ensures the consistency of the center of each diverter body, improves the coaxiality of the multi-stage diverter bodies connected in series, and enhances the stability of the pump.

[0038] Of course, the guide body 1 is connected in series in multiple stages, and the multiple stages of the guide body 1 are installed in series in the pump barrel 4. In order to ensure the coaxiality of the multiple stages of the guide body 1, an annular inner boss 106 extending axially is provided at the upper end of the guide body 1, and an annular outer boss 107 extending axially is provided at the lower end of the guide body 1. When the two adjacent stages of the guide body 1 are assembled, the annular inner boss 106 is inserted into the inner circle of the annular outer boss 107, thereby positioning the outer edges of the adjacent guide bodies 1 to further ensure the coaxiality.

[0039] Based on the support sleeve 14 being provided on the guide vane 103 inside the guide body 1, the guide body 1 is mounted on the outer ring of the support sleeve 14, and the central axis of the support sleeve 14 serves as the central axis of the guide body 1. When the outer peripheral surface of the guide body 1 and the support sleeve 14 produce a central axis offset, a stainless steel positioning ring is packaged on the outer ring of the guide body 1. By processing and cutting the stainless steel positioning ring, the central axis of the guide body is made to be the central axis of the support sleeve.

[0040] In a specific embodiment of this case, the guide body 1 comprises an upper guide body cover 101 and a lower guide body cover 102, which are spliced ​​together along the axial direction. The axial ends of the positioning ring 104 are respectively mounted on the upper guide body cover 101 and the lower guide body cover 102. The guide body 1 is composed of the upper guide body cover 101 and the lower guide body cover 102, which are spliced ​​together along the axial direction. The guide vanes 103 are fixedly mounted within the upper guide body cover 101. The lower guide body cover 102 is used to house the impeller 2 and cooperates with the guide body 1 to form a liquid flow channel within the guide body.

[0041] In order to avoid processing errors on the periphery of the connected flow guide upper cover 101 and the flow guide lower cover 102, a stainless steel positioning ring is installed on the periphery of the flow guide upper cover 101 and the flow guide lower cover 102 at the same time. The stainless steel positioning ring serves to fix the flow guide upper cover 101 and the flow guide lower cover 102 into an integrated structure, thereby improving the structural assembly strength.

[0042] Furthermore, the positioning ring 104 is installed from one end of the diverter cover 101, and the lower end of the diverter cover 102 is provided with a limiting step 105 for limiting the installation position of the positioning ring 104. During the liquid pumping process of the multi-stage diverter 1, the liquid will provide pressure to squeeze the diverter 1 from the diverter cover 101 to the diverter cover 102. When the stainless steel positioning ring is assembled with the diverter cover 101 and the diverter cover 102, the stainless steel positioning ring is located at the upper part of the diverter 1, specifically, it is mounted on the outer periphery of the diverter cover 101 and the upper half of the diverter cover 102. The lower end of the diverter cover 102 is provided with a ring-shaped limiting step 105, and the stainless steel positioning ring is located at the upper part of the diverter 1, specifically, it is mounted on the outer periphery of the diverter cover 101 and the upper half of the diverter cover 102. During the process of inserting the ring from the diverter cover 101 and further inserting it onto the diverter cover 102, the stainless steel positioning ring will drive the diverter cover 101 to be pressed onto the diverter cover 102. When the stainless steel positioning ring is inserted to the position of the limit step 105, the stainless steel positioning ring presses the limit step 105, and the diverter cover 101 presses the diverter cover 102, so that the diverter cover 101, the diverter cover 102 and the stainless steel positioning ring are assembled into an integrated structure. The above embodiments are worth mentioning that the upper and lower are used to indicate the position of the diverter cover and the diverter cover when they are arranged up and down, and are not used to limit the scope of the diverter structure.

[0043] In a specific embodiment of the present case, the supporting sleeve 14 is a ceramic sleeve, a sleeve mounting hole is provided in the middle of the guide vane 103, and positioning structures for positioning the sleeve mounting hole and the mounting end surface of the ceramic sleeve 14 are provided.

[0044] In a specific embodiment of the present case, a plane bearing 12 is provided on the outlet side of the guide vane 103. The plane bearing 12 includes a support side and an embedded side. The outer diameter of the embedded side is larger than the outer diameter of the support side.

[0045] The inner ring of the guide vane 103 is provided with an embedding groove for embedding a plane bearing, and the ceramic sleeve 14 is in abutment with the plane bearing 12 .

[0046] The guide body 1 is a fixed installation structure in the pump body, and the pump shaft 3 rotates in the guide body, generating radial contact with the pump shaft through hole of the guide body 1. In order to improve the inner ring strength of the pump shaft through hole, the inner ring of the plane bearing 12 is a bearing through hole. In order to ensure its installation strength on the guide body, the plane bearing 12 is provided with a step structure consisting of a supporting side 121 and an embedding side 122. The outer diameter of the embedding side 122 is larger than the outer diameter of the supporting side 121. Correspondingly, the inner hole of the guide vane 103 is provided with an embedding groove of a step structure. The axial support strength can be improved by the step structure between the embedding groove and the plane bearing 12. The plane bearing 12 is in abutment with the support sleeve 14 inside the guide vane 103. Between the plane bearing 12 and the impeller 2, the impeller plane bearing 23 and the plane bearing 12 are used to ensure the rotational support stability of the impeller 2 and the guide vane 103.

[0047] Furthermore, the inner wall of the bearing mounting hole features an inwardly projecting limiting protrusion, and the outer wall of the ceramic sleeve 14 is provided with a snap-fitting groove 141 that mates with the limiting protrusion. Multiple groups of these limiting protrusions and snap-fitting grooves 141 surround the circumference of the bearing mounting hole. The snap-fitting grooves 141 and limiting protrusions are arranged intermittently on the outer ring of the ceramic sleeve, providing both axial support and limiting position. This also provides a rotational restraint mechanism for the ceramic sleeve through multi-point support, further enhancing the stability of the ceramic sleeve and deflector assembly.

[0048] As shown in FIG4 , FIG4 is a cross-sectional view of the guide body support structure of the multi-stage centrifugal pump in FIG1 along the AA direction.

[0049] Based on the multi-stage centrifugal pump guide body support structure provided in the above embodiment, the present invention also provides a multi-stage centrifugal pump, including a pump body and a pump shaft. The pump shaft is provided with multiple groups of impellers and guide bodies arranged in stages. The guide body has the multi-stage centrifugal pump guide body support structure provided in the above embodiment. The inner ring of the ceramic bearing is provided with a rotor bearing sleeved on the pump shaft. A coaxially arranged ceramic sleeve 14 and rotor bearing 15 are arranged. The rotor bearing 15 is sleeved on the pump shaft 3 and rotates synchronously with the pump shaft 3. The ceramic sleeve 14 is fixed on the guide body 1. The rotational support of the rotor bearing 15 and the ceramic sleeve 14 provides radial support for the pump shaft.

[0050] Since the multi-stage centrifugal pump adopts the multi-stage centrifugal pump guide body support structure of the above embodiment, the beneficial effects of the multi-stage centrifugal pump brought by the multi-stage centrifugal pump guide body support structure can be referred to the above embodiment.

[0051] In a specific embodiment of the present case, there is a first fitting gap 401 between the rotor bearing 15 and the pump shaft 3 , and a second fitting gap 402 between the support sleeve 14 and the rotor bearing 15 . The first fitting gap 401 is larger than the second fitting gap 402 .

[0052] Preferably, the fitting tolerance of the second fitting gap 402 is 0.04-0.06.

[0053] The pump shaft 3 and the rotor bearing 15 are spline-fitted together. The rotation of the pump shaft 3 drives the rotor bearing 15 to rotate together. During the operation of the multi-stage centrifugal pump, the pump shaft 3 is subject to radial deviation due to factors such as the coaxiality of the support and the impact of the liquid. By providing a smaller second fitting clearance 14 between the rotor bearing 15 and the support sleeve 14, the impact caused by the radial swing of the rotor bearing 15 caused by the pump shaft is reduced, and the support stability between the rotor bearing 15 and the support sleeve 14 is improved. At the same time, a larger first fitting clearance 401 is provided between the pump shaft 3 and the support sleeve 15. The spline transmission structure between the pump shaft 3 and the rotor bearing 15 and the larger radial swing adjustment clearance between the pump shaft 3 and the rotor bearing 15 improve the radial adjustment capability of the pump shaft 3, further reduce the radial impact and radial pressure directly transmitted from the pump shaft 3 to the support sleeve 14, and overall improve the stability of the rotation support structure between the pump shaft 3 and the guide vane 103.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to fall within the scope of protection of the present invention.

Claims

1. A multi-stage centrifugal pump guide body support structure, characterized in that: A guide vane is arranged in the guide body, a pump shaft support sleeve is fixedly installed in the middle of the guide vane, and the guide body is arranged to be a guide body that shares a central axis with the support sleeve.

2. The multi-stage centrifugal pump flow guide support structure according to claim 1, characterized in that: A positioning ring is mounted on the outer periphery of the flow guide body, and the positioning ring is processed into a positioning ring whose outer periphery is coaxial with the supporting sleeve.

3. The multi-stage centrifugal pump flow guide support structure according to claim 2, characterized in that: The guide body comprises a guide body upper cover and a guide body lower cover which are axially spliced ​​and matched, and two axial ends of the positioning ring are respectively mounted on the guide body upper cover and the guide body lower cover.

4. The multi-stage centrifugal pump flow guide support structure according to claim 3, characterized in that: The positioning ring is installed through one end of the flow guide upper cover, and the lower end of the flow guide lower cover is provided with a limiting step for limiting the installation position of the positioning ring.

5. The multi-stage centrifugal pump flow guide support structure according to any one of claims 1 to 4, characterized in that: The supporting shaft sleeve is a ceramic shaft sleeve, a shaft sleeve mounting hole is arranged in the middle of the guide vane, and positioning structures for positioning the shaft sleeve mounting hole and the mounting end surface of the ceramic shaft sleeve are arranged.

6. The multi-stage centrifugal pump flow guide support structure according to claim 5, characterized in that: The positioning ring is a stainless steel positioning ring, and the stainless steel positioning ring is processed so that the outer peripheral surface is coaxially arranged with the supporting shaft sleeve.

7. The multi-stage centrifugal pump body guide support structure according to claim 6, characterized in that: A plane bearing is arranged on the outlet side of the guide vane, the plane bearing comprises a supporting side and an embedded side, and the outer diameter of the embedded side is larger than the outer diameter of the supporting side; The inner ring of the guide vane is provided with an embedding groove for embedding the plane bearing, and the ceramic sleeve is in abutment with the plane bearing.

8. The multi-stage centrifugal pump body guide support structure according to claim 7, characterized in that: The inner wall surface of the bearing mounting hole is provided with a limiting protrusion protruding inwardly, and the outer wall surface of the ceramic sleeve is provided with a clamping groove matched with the limiting protrusion; The limiting protrusions and the clamping grooves include multiple groups surrounding the circumference of the bearing mounting hole.

9. A multi-stage centrifugal pump, comprising a pump body and a pump shaft, wherein the pump shaft is provided with a plurality of impellers and guide bodies arranged in stages, characterized in that: The flow guide body has a multi-stage centrifugal pump flow guide body support structure as claimed in any one of claims 1 to 8, and the inner ring of the ceramic bearing is provided with a rotor bearing sleeved on the pump shaft.

10. The multistage centrifugal pump according to claim 9, characterized in that: A first fitting clearance is defined between the rotor bearing and the pump shaft, and a second fitting clearance is defined between the support sleeve and the rotor bearing. The first fitting clearance is greater than the second fitting clearance.

11. The multistage centrifugal pump according to claim 10, characterized in that: The fitting tolerance of the second fitting gap is 0.04-0.06.

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