A multistage centrifugal pump

Abstract

This utility model relates to the technical field of pumps and discloses a multi-stage centrifugal pump. The pump shaft sleeve is equipped with a balance sleeve located within the inlet and outlet sections. A first thrust groove is provided on the end face of the balance sleeve facing the high-pressure section, with its opening facing the high-pressure section. The high-pressure section has a high-pressure chamber for pressurizing the fluid. A high-pressure balance flow channel is provided between the inlet / outlet section and the high-pressure section, communicating with the high-pressure chamber. The first thrust groove is also connected to the high-pressure balance flow channel. This multi-stage centrifugal pump utilizes a high-pressure medium to automatically position the balance sleeve, eliminating the need for an external adjustment mechanism. The continuous action of the high-pressure medium dynamically balances the axial force generated during pump shaft operation, preventing shaft movement and improving the operational stability and pressure output efficiency of the multi-stage centrifugal pump.

Description

Technical Field

[0001] This utility model relates to the technical field of pumps, and in particular to a multistage centrifugal pump. Background Technology

[0002] Multistage centrifugal pumps, widely used in industrial fluid transport, have always faced the critical challenge of axial force balance as a key factor limiting their performance. Traditional technologies typically employ mechanical balancing discs or drums to achieve axial force balance, but these structures have significant shortcomings in practical operation. Mechanical contact balancing devices inevitably experience wear, which not only shortens equipment maintenance cycles but also affects operational stability. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. It provides a multi-stage centrifugal pump that utilizes a high-pressure medium to automatically position and balance the shaft sleeve, eliminating the need for an external adjustment mechanism. The continuous action of the high-pressure medium dynamically balances the axial force generated during pump shaft operation, preventing shaft misalignment and improving the operational stability and pressure output efficiency of the multi-stage centrifugal pump.

[0004] To achieve the above objectives, this utility model provides a multi-stage centrifugal pump, including a low-pressure section, a high-pressure section, an inlet / outlet section, a transition bend, and a pump shaft. The pump shaft is coaxially disposed in the low-pressure section, the inlet / outlet section, and the high-pressure section, respectively. The inlet / outlet section is located between the low-pressure section and the high-pressure section. The low-pressure section has a medium inlet, and the inlet / outlet section has a medium outlet. The low-pressure section is connected to one end of the transition bend through the high-pressure section, and the other end of the transition bend is connected to the end of the high-pressure section away from the inlet / outlet section. The high-pressure section is connected to the medium outlet.

[0005] The pump shaft sleeve is provided with a balance shaft sleeve located in the inlet and outlet water section. The end face of the balance shaft sleeve facing the high pressure section is provided with a first thrust groove. The opening of the first thrust groove is set towards the high pressure section. The high pressure section is provided with a high pressure cavity for pressurizing fluid. A high pressure balance flow channel is provided between the inlet and outlet water section and the high pressure section. The high pressure balance flow channel is connected to the high pressure cavity. The first thrust groove is connected to the high pressure balance flow channel.

[0006] As a preferred embodiment, the first thrust groove is annular.

[0007] As a preferred embodiment, the high-pressure section is provided with a second thrust groove on the side facing the balance bushing. The second thrust groove is connected to the high-pressure balance flow channel. The opening of the second thrust groove faces the first thrust groove. The first thrust groove and the second thrust groove define a thrust cavity.

[0008] As a preferred embodiment, the balance shaft is fitted with a displacement cavity, the opening of which faces the high-pressure section. The high-pressure section is equipped with a high-pressure impeller connected to the pump shaft. The high-pressure impeller protrudes towards the displacement cavity to form a high-pressure protrusion, the diameter of which is smaller than the diameter of the displacement cavity.

[0009] As a preferred embodiment, the first thrust groove is located on the outer periphery of the displacement cavity.

[0010] As a preferred embodiment, one end of the balance bushing is provided with a bushing positioning groove, the opening of the bushing positioning groove is set towards the low-pressure section, and the bushing positioning groove is engaged with the pump shaft.

[0011] As a preferred embodiment, the bushing positioning groove is annular.

[0012] As a preferred embodiment, the pump shaft is provided with a shaft positioning groove, a positioning ring is engaged in the shaft positioning groove, and the shaft sleeve positioning groove abuts against the positioning ring.

[0013] As a preferred embodiment, the low-pressure section includes multiple low-pressure intermediate sections, each equipped with a low-pressure impeller. The multiple low-pressure intermediate sections are sequentially connected to form a low-pressure cavity. The pump shaft passes through the low-pressure cavity, which is connected to the medium inlet. The low-pressure impeller is located within the low-pressure cavity and connected to the pump shaft.

[0014] As a preferred embodiment, the high-pressure section includes multiple high-pressure intermediate sections, which are sequentially connected to form the high-pressure cavity. The pump shaft passes through the high-pressure cavity, and the high-pressure cavity is connected to the medium outlet.

[0015] This utility model discloses a multi-stage centrifugal pump, which, compared with the prior art, has the following advantages: It includes a low-pressure section, a high-pressure section, an inlet / outlet section, a transition bend, and a pump shaft. The pump shaft coaxially runs through the low-pressure section, the inlet / outlet section, and the high-pressure section. The inlet / outlet section is located between the low-pressure section and the high-pressure section, forming a multi-stage series structure. The low-pressure section has a medium inlet for introducing the fluid to be pressurized; the inlet / outlet section has a medium outlet for outputting the finally pressurized fluid. The fluid enters the low-pressure section from the medium inlet, is initially pressurized by the low-pressure impeller, and then flows to the inlet / outlet section. The inlet / outlet section guides the initially pressurized fluid to the transition bend, which then transports the fluid to the inlet end of the high-pressure section, i.e., the end away from the inlet / outlet section. The high-pressure section performs secondary pressurization on the fluid, and the pressurized high-pressure fluid flows out from the high-pressure section and is finally output through the medium outlet of the inlet / outlet section. A balance sleeve is fitted on the pump shaft, located inside the inlet / outlet section, and its end face facing the high-pressure section has a first thrust groove. A high-pressure chamber is formed within the high-pressure section. A high-pressure balancing flow channel is provided between the inlet / outlet section and the high-pressure section, connecting the high-pressure chamber to the first thrust groove. The high-pressure medium in the high-pressure section enters the first thrust groove through the high-pressure balancing flow channel, pushing the balance sleeve towards the low-pressure side to position it against the pump shaft, achieving axial positioning. The balance sleeve is automatically positioned using the high-pressure medium, eliminating the need for external adjustment mechanisms. The continuous action of the high-pressure medium dynamically balances the axial force generated during pump shaft operation, preventing shaft movement and improving the operational stability and pressure output efficiency of the multi-stage centrifugal pump. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model.

[0017] Figure 2 This is an embodiment of the present utility model. Figure 1 A magnified structural diagram at point 3A.

[0018] Figure 3 This is a cross-sectional structural diagram of the balance bushing according to an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the structure of one end of the balance bushing in an embodiment of this utility model.

[0020] Figure 5 This is a schematic diagram of the structure of the other end of the balance bushing in an embodiment of this utility model.

[0021] In the picture:

[0022] 1001, Low-pressure section; 1002, Medium inlet; 1009, Low-pressure intermediate section; 1011, Low-pressure cavity; 1013, Low-pressure impeller;

[0023] 2001, High-pressure section; 2008, High-pressure intermediate section; 2010, High-pressure cavity; 2012, High-pressure impeller; 2013, Second thrust groove; 2014, High-pressure protrusion;

[0024] 3001, Inlet / Outlet Section; 3002, Medium Outlet;

[0025] 4001, Transition bend;

[0026] 5001, Pump shaft; 5004, Shaft positioning groove; 5005, Positioning ring;

[0027] 7001, Balance bushing; 7002, First thrust groove; 7003, Thrust chamber; 7004, High-pressure balance flow channel; 7005, Displacement chamber; 7006, Bushing positioning groove. Detailed Implementation

[0028] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0029] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" used to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0030] In the description of this utility model, it should be understood that the terms "connected," "linked," and "fixed," etc., used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or a welded connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] like Figures 1 to 5As shown, a preferred embodiment of the present invention provides a multi-stage centrifugal pump, comprising a low-pressure section 1001, a high-pressure section 2001, an inlet / outlet section 3001, a transition bend 4001, and a pump shaft 5001. The pump shaft 5001 is coaxially disposed in the low-pressure section 1001, the inlet / outlet section 3001, and the high-pressure section 2001. The inlet / outlet section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001. The low-pressure section 1001 is provided with a medium inlet 1002, and the inlet / outlet section 3001 is provided with a medium outlet 3002. The low-pressure section 1001 is connected to one end of the transition bend 4001 through the high-pressure section 2001, and the other end of the transition bend 4001 is connected to the end of the high-pressure section 2001 away from the inlet / outlet section 3001. The high-pressure section 2001 is connected to the medium outlet 3002.

[0032] The pump shaft 5001 is fitted with a balance shaft sleeve 7001 located in the inlet / outlet section 3001. The end face of the balance shaft sleeve 7001 facing the high pressure section 2001 is provided with a first thrust groove 7002. The opening of the first thrust groove 7002 is set towards the high pressure section 2001. The high pressure section 2001 is provided with a high pressure chamber 2010 for pressurizing fluid. A high pressure balance flow channel 7004 is provided between the inlet / outlet section 3001 and the high pressure section 2001. The high pressure balance flow channel 7004 is connected to the high pressure chamber 2010. The first thrust groove 7002 is connected to the high pressure balance flow channel 7004.

[0033] This utility model discloses a multistage centrifugal pump, comprising a low-pressure section 1001, a high-pressure section 2001, an inlet / outlet section 3001, a transition bend 4001, and a pump shaft 5001. The pump shaft 5001 coaxially passes through the low-pressure section 1001, the inlet / outlet section 3001, and the high-pressure section 2001. The inlet / outlet section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001, forming a multistage series structure. The low-pressure section 1001 is provided with a medium inlet 1002 for introducing the fluid to be pressurized; the inlet / outlet section 3001 is provided with a medium outlet 3002 for outputting the finally pressurized fluid. The fluid enters the low-pressure section 1001 from the medium inlet 1002, is initially pressurized by the low-pressure impeller 1013, and then flows to the inlet / outlet section 3001. The inlet / outlet section 3001 guides the initially pressurized fluid to the transition bend 4001, which then transports the fluid to the inlet end of the high-pressure section 2001, i.e., the end furthest from the inlet / outlet section 3001. The high-pressure section 2001 further pressurizes the fluid, and the pressurized high-pressure fluid flows out of the high-pressure section 2001 and is finally output through the medium outlet 3002 of the inlet / outlet section 3001. A balance sleeve 7001 is fitted onto the pump shaft 5001, located inside the inlet / outlet section 3001, with a first thrust groove 7002 on its end face facing the high-pressure section 2001. A high-pressure chamber 2010 is formed within the high-pressure section 2001. A high-pressure balance flow channel 7004 connects the high-pressure chamber 2010 to the first thrust groove 7002 between the inlet / outlet section 3001 and the high-pressure section 2001. The high-pressure medium in the high-pressure section 2001 enters the first thrust groove 7002 through the high-pressure balance flow channel 7004, pushing the balance sleeve 7001 to move towards the low-pressure side, positioning it in conjunction with the pump shaft 5001 to achieve axial positioning. The balance sleeve 7001 is automatically positioned using the high-pressure medium, eliminating the need for external adjustment mechanisms. The continuous action of the high-pressure medium dynamically balances the axial force generated by the pump shaft 5001 during operation, preventing shaft movement and improving the operational stability and pressure output efficiency of the multi-stage centrifugal pump.

[0034] Furthermore, the first thrust groove 7002 is annular. A high-pressure chamber 2010 is provided within the high-pressure section 2001, and a high-pressure balance flow channel 7004 is provided between the inlet / outlet section 3001 and the high-pressure section 2001, connecting the high-pressure chamber 2010 to the annular first thrust groove 7002. The high-pressure medium enters the annular first thrust groove 7002 through the high-pressure balance flow channel 7004. The opening of the annular first thrust groove 7002 faces the high-pressure section 2001, creating a uniform pressure distribution within the annular first thrust groove 7002, ensuring that the high-pressure medium acts evenly on the entire end face. The annular structure ensures that the high-pressure medium acts evenly on the balance sleeve 7001, avoiding localized stress concentration. The high-pressure medium acts on the entire annular end face of the balance sleeve 7001, generating a stable axial thrust that pushes the balance sleeve 7001 towards the low-pressure side. The cooperation between the annular thrust groove and the high-pressure balance flow channel 7004 ensures continuous and stable axial thrust, improving positioning reliability. Uniform pressure distribution effectively suppresses pump shaft vibration and extends bearing life.

[0035] Furthermore, a second thrust groove 2013 is provided on the side of the high-pressure section 2001 facing the balance sleeve 7001. The second thrust groove 2013 is connected to the high-pressure balance flow channel 7004, and the opening of the second thrust groove 2013 faces the first thrust groove 7002. The first thrust groove 7002 and the second thrust groove 2013 define a thrust cavity 7003. A second thrust groove 2013 is provided on the end face of the high-pressure section 2001, and the thrust cavity 7003 is formed by the first thrust groove 7002 and the second thrust groove 2013 being arranged opposite to and connected. The high-pressure balance flow channel 7004 is connected to both the first thrust groove 7002 and the second thrust groove 2013. The high-pressure medium enters the thrust cavity 7003 simultaneously through the high-pressure balance flow channel 7004. The medium forms a uniform pressure field in the thrust cavity 7003, which acts on the mating surfaces of the first and second thrust grooves 2013 respectively, pushing the balance sleeve 7001 to move towards the low-pressure side, thereby achieving axial positioning. The first and second thrust grooves work together to enhance the balance effect within a limited space.

[0036] Furthermore, the balance sleeve 7001 is provided with a displacement cavity 7005, the opening of which faces the high-pressure section 2001. The high-pressure section 2001 is provided with a high-pressure impeller 2012 connected to the pump shaft 5001. The high-pressure impeller 2012 protrudes towards the displacement cavity 7005, forming a high-pressure protrusion 2014, the diameter of which is smaller than the diameter of the displacement cavity 7005. The continuous action of the high-pressure medium keeps the balance sleeve 7001 in an optimal balanced position. The pump shaft 5001 drives the high-pressure impeller 2012 to rotate. When the axial force decreases, the balance sleeve 7001 returns to its original position under the action of the reverse force, and the high-pressure protrusion 2014 re-approaches the displacement cavity 7005. The cooperation between the high-pressure protrusion 2014 and the displacement cavity 7005 avoids rigid collision between the balance sleeve 7001 and the high-pressure section 2001, improving operational safety. The displacement cavity 7005 provides ample axial movement space, allowing the balance bushing 7001 to be freely adjusted in position to adapt to different working conditions.

[0037] Furthermore, the first thrust groove 7002 is located on the outer periphery of the displacement cavity 7005. The first thrust groove 7002 on the outer periphery provides the main balancing force, and its placement increases the bearing radius, while the structure of the displacement cavity 7005 ensures safe avoidance. The placement of the first thrust groove 7002 on the outer periphery of the displacement cavity 7005 retains its safe avoidance function while improving the balancing effect through optimized positioning.

[0038] Furthermore, one end of the balance bushing 7001 is provided with a bushing positioning groove 7006, the opening of which faces the low-pressure section 1001, and the bushing positioning groove 7006 is engaged with the pump shaft 5001. By engaging the balance bushing 7006 with the pump shaft 5001, excessive displacement of the balance bushing 7001 can be prevented.

[0039] In one embodiment, the bushing positioning groove 7006 is an annular groove structure, and the pump shaft 5001 is provided with a positioning flange at the corresponding position of the bushing positioning groove 7006. The positioning flange and the bushing positioning groove 7006 form a snap-fit ​​engagement.

[0040] Furthermore, the bushing positioning groove 7006 is annular. Axial force is transmitted evenly through the annular contact surface, resulting in uniform pressure distribution on the contact surface and avoiding localized stress concentration.

[0041] Furthermore, the pump shaft 5001 is provided with a shaft positioning groove 5004, which engages with a positioning ring 5005. The shaft sleeve positioning groove 7006 abuts against the positioning ring 5005. The positioning ring 5005 serves as an axial limiting device, preventing excessive displacement of the balance shaft sleeve 7001. By providing the shaft positioning groove 5004 on the pump shaft 5001 and cooperating with the positioning ring 5005, precise positioning and reliable limiting of the balance shaft sleeve 7001 are achieved.

[0042] Furthermore, the low-pressure section 1001 includes multiple low-pressure intermediate sections 1009, each equipped with a low-pressure impeller 1013. These multiple low-pressure intermediate sections 1009 are sequentially connected to form a low-pressure cavity 1011. The pump shaft 5001 passes through the low-pressure cavity 1011, which is connected to the medium inlet 1002. The low-pressure impeller 1013 is located within the low-pressure cavity 1011 and connected to the pump shaft 5001. Through the sequential connection of modular, multi-stage low-pressure sections 1001, efficient and gradual pressurization of the medium is achieved. This configuration is flexible, maintenance is convenient, and operation is stable. The number of low-pressure intermediate sections 1009 can be flexibly adjusted according to actual needs, ensuring the pump unit always maintains optimal operating conditions.

[0043] In one embodiment, it is composed of 3-5 identical low-pressure intermediate sections 1009 connected in series. Each low-pressure intermediate section 1009 is provided with an annular flow channel and a mechanical seal mounting groove. A sealing gasket is connected in the mechanical seal mounting groove. Multiple annular flow channels are connected to form a low-pressure cavity 1011. A low-pressure impeller 1013 is installed in each low-pressure intermediate section 1009. The low-pressure impeller 1013 is fixed to the pump shaft 5001 by a key connection.

[0044] Furthermore, the high-pressure section 2001 includes multiple high-pressure intermediate sections 2008, which are sequentially connected to form a high-pressure chamber 2010. The pump shaft 5001 passes through the high-pressure chamber 2010, which is connected to the medium outlet 3002. The initially pressurized medium enters the high-pressure intermediate section 2008, which is away from the inlet / outlet section 3001, through the transition bend 4001. The medium is accelerated by the high-pressure impeller 2012, and the high-pressure medium is output through the medium outlet 3002. By sequentially connecting multiple high-pressure intermediate sections 2008, efficient and stable pressurization of the medium is achieved. The number of high-pressure intermediate sections 2008 can be flexibly adjusted according to the final output pressure requirement, so that the pump set always maintains optimal operating performance.

[0045] As one embodiment, it is composed of 3-5 identical high-pressure intermediate sections 2008 connected in series. Each high-pressure intermediate section 2008 is provided with an annular flow channel and a mechanical seal mounting groove. A sealing gasket is connected in the mechanical seal mounting groove. Multiple annular flow channels are connected to form a high-pressure cavity 2010. A high-pressure impeller 2012 is installed in each high-pressure intermediate section 2008. The high-pressure impeller 2012 is fixed to the pump shaft 5001 by a key connection.

[0046] In summary, this utility model embodiment provides a multi-stage centrifugal pump, including a low-pressure section 1001, a high-pressure section 2001, an inlet / outlet section 3001, a transition bend 4001, and a pump shaft 5001. The pump shaft 5001 coaxially passes through the low-pressure section 1001, the inlet / outlet section 3001, and the high-pressure section 2001. The inlet / outlet section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001, forming a multi-stage series structure. The low-pressure section 1001 is provided with a medium inlet 1002 for introducing the fluid to be pressurized; the inlet / outlet section 3001 is provided with a medium outlet 3002 for outputting the finally pressurized fluid. The fluid enters the low-pressure section 1001 from the medium inlet 1002, is initially pressurized by the low-pressure impeller 1013, and then flows to the inlet / outlet section 3001. The inlet / outlet section 3001 guides the initially pressurized fluid to the transition bend 4001, which then transports the fluid to the inlet end of the high-pressure section 2001, i.e., the end furthest from the inlet / outlet section 3001. The high-pressure section 2001 further pressurizes the fluid, and the pressurized high-pressure fluid flows out of the high-pressure section 2001 and is finally output through the medium outlet 3002 of the inlet / outlet section 3001. A balance sleeve 7001 is fitted onto the pump shaft 5001, located inside the inlet / outlet section 3001, with a first thrust groove 7002 on its end face facing the high-pressure section 2001. A high-pressure chamber 2010 is formed within the high-pressure section 2001. A high-pressure balance flow channel 7004 connects the high-pressure chamber 2010 to the first thrust groove 7002 between the inlet / outlet section 3001 and the high-pressure section 2001. The high-pressure medium in the high-pressure section 2001 enters the first thrust groove 7002 through the high-pressure balance flow channel 7004, pushing the balance sleeve 7001 to move towards the low-pressure side, positioning it in conjunction with the pump shaft 5001 to achieve axial positioning. The balance sleeve 7001 is automatically positioned using the high-pressure medium, eliminating the need for external adjustment mechanisms. The continuous action of the high-pressure medium dynamically balances the axial force generated by the pump shaft 5001 during operation, preventing shaft movement and improving the operational stability and pressure output efficiency of the multi-stage centrifugal pump.

[0047] The above are merely preferred embodiments of this utility model. It should be noted that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this utility model, and these improvements and substitutions should also be considered within the protection scope of this utility model.

Claims

1. A multistage centrifugal pump, characterized in that: It includes a low-pressure section, a high-pressure section, an inlet / outlet water section, a transition bend, and a pump shaft. The pump shaft is coaxially installed in the low-pressure section, the inlet / outlet water section, and the high-pressure section. The inlet / outlet water section is located between the low-pressure section and the high-pressure section. The low-pressure section has a medium inlet, and the inlet / outlet water section has a medium outlet. The low-pressure section is connected to one end of the transition bend through the high-pressure section. The other end of the transition bend is connected to the end of the high-pressure section away from the inlet / outlet water section. The high-pressure section is connected to the medium outlet. The pump shaft sleeve is provided with a balance shaft sleeve located in the inlet and outlet water section. The end face of the balance shaft sleeve facing the high pressure section is provided with a first thrust groove. The opening of the first thrust groove is set towards the high pressure section. The high pressure section is provided with a high pressure cavity for pressurizing fluid. A high pressure balance flow channel is provided between the inlet and outlet water section and the high pressure section. The high pressure balance flow channel is connected to the high pressure cavity. The first thrust groove is connected to the high pressure balance flow channel.

2. The multistage centrifugal pump according to claim 1, characterized in that: The first thrust groove is annular.

3. The multistage centrifugal pump according to claim 1, characterized in that: The high-pressure section is provided with a second thrust groove on the side facing the balance shaft sleeve. The second thrust groove is connected to the high-pressure balance flow channel. The opening of the second thrust groove faces the first thrust groove. The first thrust groove and the second thrust groove define a thrust cavity.

4. The multistage centrifugal pump according to claim 3, characterized in that: The balance shaft is fitted with a displacement cavity, the opening of which faces the high-pressure section. The high-pressure section is equipped with a high-pressure impeller connected to the pump shaft. The high-pressure impeller protrudes towards the displacement cavity to form a high-pressure protrusion, the diameter of which is smaller than the diameter of the displacement cavity.

5. The multistage centrifugal pump according to claim 4, characterized in that: The first thrust groove is located on the outer periphery of the displacement cavity.

6. The multistage centrifugal pump according to claim 1, characterized in that: One end of the balance bushing is provided with a bushing positioning groove, the opening of the bushing positioning groove is set towards the low-pressure section, and the bushing positioning groove is engaged with the pump shaft.

7. The multistage centrifugal pump according to claim 6, characterized in that: The bushing positioning groove is annular.

8. The multistage centrifugal pump according to claim 6, characterized in that: The pump shaft is provided with a shaft positioning groove, a positioning ring is engaged in the shaft positioning groove, and the shaft sleeve positioning groove abuts against the positioning ring.

9. The multistage centrifugal pump according to claim 1, characterized in that: The low-pressure section includes multiple low-pressure intermediate sections, each equipped with a low-pressure impeller. The multiple low-pressure intermediate sections are connected in sequence to form a low-pressure cavity. The pump shaft passes through the low-pressure cavity and is connected to the medium inlet. The low-pressure impeller is located in the low-pressure cavity and connected to the pump shaft.

10. The multistage centrifugal pump according to claim 4, characterized in that: The high-pressure section includes multiple high-pressure intermediate sections, which are sequentially connected to form the high-pressure cavity. The pump shaft passes through the high-pressure cavity, and the high-pressure cavity is connected to the medium outlet.

Images