Reliable double-shell self-balancing multistage centrifugal pump

Abstract

The invention relates to the technical field of pumps, and discloses a reliable double-shell self-balancing multi-stage centrifugal pump, a low-pressure section is provided with a medium inlet and an inducer chamber, the two ends of the inducer chamber communicate with the medium inlet and a fluid cavity correspondingly, and an inducer connected to a pump shaft is arranged in the inducer chamber; the pump shaft sleeve is provided with a throttling ring, the throttling ring is located at the end, away from the low-pressure section, of the high-pressure section, drainage threads are arranged on the periphery of the throttling ring, a throttling channel is defined between the drainage threads and the high-pressure section, the mechanical seal base is provided with a pressure relief channel, one end of the throttling channel is communicated with the fluid cavity, and the other end of the throttling channel is communicated with the pressure relief channel. And the pressure relief channel is communicated with the inducer chamber through a pressure relief pipe. According to the reliable double-shell self-balancing multi-stage centrifugal pump, the throttling ring is driven by the pump shaft to rotate, the inlet pressure is effectively increased, cavitation is prevented, the throttling channel has the pressure relief effect on the high-pressure section, the impact load of a high-pressure medium on the pump shaft, the bearing and the bearing box is relieved, the operation stability of the pump is improved, and the service life of the pump is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pumps, in particular to a reliable double-casing self-balanced multi-stage centrifugal pump. BACKGROUND

[0002] The reliable double-casing self-balanced multi-stage centrifugal pump is a special centrifugal pump with a large number of impellers, guide vanes and middle sections, a plurality of impellers are installed in series in positive and negative directions on a pump shaft and placed in a pump cavity formed by a plurality of guide vanes in positive and negative directions and a plurality of middle sections in positive and negative directions, and the pump has a very high lift (pressure) of 3600 m or more, a flow rate of 5000 m3 / h or more, and a rotation speed of 1500 r / min to 7500 r / min. Therefore, the application range of the reliable double-casing self-balanced multi-stage centrifugal pump is very wide, such as special industrial fields of steel descaling engineering, seawater desalination engineering, coal mining engineering, oil field water injection engineering, long-distance oil transportation engineering, high-pressure pipeline transportation process of a refinery, high-pressure water supply engineering of a power plant boiler, LNG low-temperature high-pressure liquid transportation engineering, offshore ship and offshore platform, etc. The temperature of the conveyed medium has various characteristics of low temperature, normal temperature, high temperature and high-low temperature change, and the application working condition environment also has the characteristics of normal temperature, high temperature and low temperature. Therefore, the high anti-cavitation, stability, reliability and safety of the reliable double-casing self-balanced multi-stage centrifugal pump during use and operation are very important.

[0003] In the existing reliable double-casing self-balanced multi-stage centrifugal pump technology, the pump is not designed as a double-anti-cavitation structure, and a double-high anti-cavitation system is not provided, so that the necessary cavitation allowance of the pump is very large (i.e. NPSHr≥20 m, and some are even larger), and the anti-cavitation performance is not good. Due to the change of the working condition of the pipe network system during the operation of the pump, the multi-stage centrifugal pump is very prone to cavitation, such as cavitation under the working conditions of an increase in the temperature of the conveyed medium, insufficient lift of the pump suction device, excessive flow rate of the pump, and too small flow rate of the pump. Cavitation will cause the multi-stage pump to vibrate and make noise, and the explosion of bubbles produced by cavitation in the medium flow will cause the impeller, guide vane and middle section of the multi-stage pump to be severely damaged by bubble explosion and corrosion, so that the pump cannot work, and the service life and reliability of the pump are severely shortened. In order to ensure that the reliable double-casing self-balanced multi-stage centrifugal pump does not cavitate during operation, the lift (i.e. the required pressure lift NPSHa at the inlet of the water inlet section) of the pump suction device equipment or device system needs to be higher than the necessary cavitation allowance value of the pump (i.e. NPSHa>20 m), thereby increasing the production cost, operation cost and maintenance cost of the multi-stage pump. SUMMARY

[0004] The reliable double-shell self-balancing multi-stage centrifugal pump aims to at least solve one of the technical problems existing in the prior art. The pump shaft drives the throttle ring to rotate, effectively raises the inlet pressure, prevents cavitation from occurring, the throttle channel has a pressure relief effect on the high-pressure section, reduces the impact load of the high-pressure medium on the pump shaft, bearing and bearing box, and improves the operation stability and service life of the pump.

[0005] To achieve the above-mentioned purpose, the reliable double-shell self-balancing multi-stage centrifugal pump comprises a low-pressure section, a high-pressure section, a pump shaft, a pressure relief pipe and a mechanical seal seat, the low-pressure section and the high-pressure section are communicated to form a fluid cavity, the mechanical seal seat is connected to one side of the high-pressure section away from the low-pressure section, and the pump shaft is respectively arranged in the low-pressure section, the high-pressure section and the mechanical seal seat; the low-pressure section is provided with a medium inlet and an inducer chamber, both ends of the inducer chamber are respectively communicated with the medium inlet and the fluid cavity, and the inducer chamber is provided with an inducer connected to the pump shaft.

[0006] The pump shaft is provided with a throttle ring, the throttle ring is located at one end of the high-pressure section away from the low-pressure section, the outer periphery of the throttle ring is provided with a drainage thread, the drainage thread and the high-pressure section define a throttle channel, the mechanical seal seat is provided with a pressure relief channel, one end of the throttle channel is communicated with the fluid cavity, and the other end is communicated with the pressure relief channel, and the pressure relief channel is communicated with the inducer chamber through the pressure relief pipe.

[0007] As a preferred scheme, the pump shaft is provided with a mechanical seal shaft sleeve, the mechanical seal shaft sleeve protrudes radially to form a mechanical seal shaft sleeve ring, the mechanical seal shaft sleeve ring, the mechanical seal seat and the high-pressure section define a pressure relief cavity, one end of the mechanical seal shaft sleeve is connected with the throttle ring, one end of the throttle channel is communicated with the pressure relief cavity, and one end of the pressure relief channel is communicated with the pressure relief cavity.

[0008] As a preferred scheme, the high-pressure section comprises a high-pressure impeller, a high-pressure middle section and a secondary water inlet section, the low-pressure section, the high-pressure middle section and the secondary water inlet section define the fluid cavity, the high-pressure impeller is connected to the pump shaft and located in the high-pressure middle section, the secondary water inlet section is connected to one side of the high-pressure middle section away from the low-pressure section, the secondary water inlet section is connected between the high-pressure middle section and the mechanical seal seat, the secondary water inlet section is communicated with the low-pressure section, the throttle ring and the secondary water inlet section define the throttle channel, the throttle channel is provided with a drainage inlet, the drainage inlet is located on one side of the secondary water inlet section facing the high-pressure middle section, and the other end of the secondary water inlet section and the mechanical seal seat and the mechanical seal shaft sleeve ring define the pressure relief cavity.

[0009] As a preferred solution, the inducer chamber is provided with a jet hole, the inducer is provided with an inducer suction surface on the side facing the low pressure section, the low pressure section is provided with a jet passage communicating with the pressure relief pipe, one end of the jet hole communicates with the jet passage, and the other end of the jet hole is arranged towards the inducer suction surface.

[0010] As a preferred solution, the low pressure section comprises a water inlet section and a first stage middle section, the first stage middle section is connected to the water inlet section on the side facing the high pressure section, the medium inlet is arranged on the water inlet section, the inducer chamber is arranged in the first stage middle section, the water inlet section is provided with an inducer mounting opening on the side facing the first stage middle section, the inducer chamber is provided with an inducer passage extending in the axial direction, the inducer is arranged in the inducer passage, and the two ends of the inducer passage respectively communicate with the medium inlet and the fluid cavity.

[0011] As a preferred solution, the low pressure section further comprises a low pressure middle section, the first stage middle section is connected between the water inlet section and the low pressure middle section, the end of the inducer chamber away from the water inlet section communicates with the low pressure middle section, the pump shaft is connected with a low pressure impeller, the low pressure impeller is arranged on the side of the low pressure middle section facing the inducer chamber, the inducer chamber and the first stage middle section define a degassing cavity, the inducer chamber is provided with a degassing hole, the degassing hole is arranged towards the low pressure impeller, the degassing cavity communicates with the inducer chamber through the degassing hole, and the water inlet section is provided with a degassing passage for communicating with a degassing device, the degassing passage communicates with the degassing cavity.

[0012] As a preferred solution, a transition elbow, a water inlet and outlet section, a liquid inlet main pipe and a liquid outlet main pipe are further included, the pump shaft is arranged in the water inlet and outlet section, the water inlet and outlet section is arranged between the low pressure section and the high pressure section, the low pressure section is provided with a medium inlet, the water inlet and outlet section is provided with a medium outlet, the low pressure section communicates with one end of the transition elbow through the water inlet and outlet section, and the other end of the transition elbow communicates with the end of the high pressure section away from the water inlet and outlet section, the high pressure section communicates with the water inlet and outlet section to form a fluid cavity.

[0013] A low pressure cylinder is arranged on the outer periphery of the low pressure section, the low pressure cylinder and the low pressure section define a low pressure heat exchange cavity, the low pressure heat exchange cavity is provided with a low pressure heat exchange inlet and a low pressure heat exchange outlet, a high pressure cylinder is arranged on the outer periphery of the high pressure section, the high pressure cylinder and the high pressure section define a high pressure heat exchange cavity, the high pressure heat exchange cavity is provided with a high pressure heat exchange inlet and a high pressure heat exchange outlet, the low pressure heat exchange inlet and the high pressure heat exchange inlet respectively communicate with the liquid inlet main pipe, the low pressure heat exchange outlet and the high pressure heat exchange outlet respectively communicate with the liquid outlet main pipe, and the low pressure heat exchange inlet, the low pressure heat exchange outlet, the high pressure heat exchange inlet and the high pressure heat exchange outlet are respectively connected with valve bodies.

[0014] As a preferred solution, the water inlet and outlet section assembly is located between the low pressure section and the high pressure section, the pump shaft is coaxially arranged in the low pressure section, the water inlet and outlet section assembly and the high pressure section respectively, the low pressure section is communicated with one end of the transition bend through the water inlet and outlet section assembly, and the other end of the transition bend is communicated with one end of the high pressure section away from the water inlet and outlet section assembly.

[0015] The water inlet and outlet section assembly is provided with a balance cavity, a balance hole, a medium outlet and a high pressure throttling inlet, the medium outlet and the high pressure throttling inlet are communicated with the high pressure section respectively, the high pressure throttling inlet is located between the pump shaft and the medium outlet, the high pressure throttling inlet is communicated with the balance cavity, and the balance cavity is communicated with the transition bend through the balance hole.

[0016] As a preferred solution, the water inlet and outlet section assembly includes a water inlet and outlet section, a balance shaft sleeve and a high pressure throttling ring, the two axial ends of the water inlet and outlet section are connected with the low pressure section and the high pressure section respectively, the balance cavity, the balance hole and the medium outlet are arranged in the water inlet and outlet section respectively, the high pressure throttling ring is connected to one side of the water inlet and outlet section facing the high pressure section, the balance shaft sleeve is sleeved on the outer periphery of the pump shaft, one end of the high pressure throttling ring facing the high pressure section is sleeved on the balance shaft sleeve, and the high pressure throttling ring is located in the balance cavity.

[0017] As a preferred solution, the water inlet and outlet section assembly further includes a low pressure throttling ring, the low pressure throttling ring is connected to one side of the water inlet and outlet section facing the low pressure section, the low pressure throttling ring is sleeved on one end of the balance shaft sleeve facing the low pressure section, one end of the low pressure throttling ring is located in the balance cavity and defines a medium diffusion port with the high pressure throttling ring, and the other end of the low pressure throttling ring defines a low pressure throttling outlet with the balance shaft sleeve, and the low pressure throttling outlet is communicated with the transition bend.

[0018] Compared with the prior art, the embodiment of the application has the beneficial effects that: the reliable double-shell self-balancing multi-stage centrifugal pump comprises a low-pressure section, a high-pressure section, a pump shaft, a pressure relief pipe and a mechanical seal seat, the low-pressure section and the high-pressure section are communicated to form a fluid cavity, the mechanical seal seat is connected to one side of the high-pressure section away from the low-pressure section, and the pump shaft is sequentially arranged in the low-pressure section, the high-pressure section and the mechanical seal seat. The low-pressure section is provided with a medium inlet and an inducer chamber, the two ends of the inducer chamber are communicated with the medium inlet and the fluid cavity respectively, and the inducer chamber is provided with an inducer connected to the pump shaft, thereby forming an intake and preliminary pressurization path of low-pressure medium. A throttle ring is arranged on the pump shaft and located at one end of the high-pressure section away from the low-pressure section, the throttle ring is provided with a drainage thread on the outer periphery, and the high-pressure section and the throttle ring are limited to form a throttling channel; a pressure relief channel is arranged in the mechanical seal seat, one end of the throttling channel is communicated with the fluid cavity of the high-pressure section, the other end of the throttling channel is communicated with the pressure relief channel, and the pressure relief channel is communicated with the inducer chamber through the pressure relief pipe. The rotation of the throttle ring driven by the pump shaft can actively guide the high-pressure medium in the high-pressure section to the pressure relief channel through the drainage thread structure, and then the high-pressure medium is transported to the inducer chamber through the pressure relief pipe, thereby forming a local high-pressure area near the suction inlet of the inducer, effectively raising the inlet pressure and preventing cavitation. At the same time, the high-pressure jet flow and the low-pressure medium are mixed in the inducer chamber, the entrainment effect is enhanced, the low-pressure medium is driven to flow at a high speed, the intake performance is further improved, and cavitation caused by uneven flow velocity or insufficient pressure is avoided. In addition, the drainage effect of the throttling channel also has a pressure relief effect on the high-pressure section, thereby reducing the impact load of the high-pressure medium on the pump shaft, the bearing and the bearing box, and improving the running stability and service life of the pump. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a whole structure schematic diagram of the embodiment of the application.

[0020] Figure 2 It is an enlarged structure schematic diagram of 6A in the embodiment of the application. Figure 1

[0021] Figure 3 It is an enlarged structure schematic diagram of 8B in the embodiment of the application. Figure 2

[0022] Figure 4 It is an assembly structure schematic diagram of the water inlet section, the first-stage middle section and the low-pressure middle section of the embodiment of the application.

[0023] Figure 5 It is an enlarged structure schematic diagram of 6B in the embodiment of the application. Figure 4

[0024] Figure 6 It is a cross-sectional structure schematic diagram of the water inlet section of the embodiment of the application.

[0025] Figure 7 It is a front view of the water inlet section of the embodiment of the application.

[0026] ​​​Figure 8 is the front view of the inducer wheel chamber of the embodiment of the present application.

[0027] Figure 9 is the sectional view of the inducer wheel chamber of the embodiment of the present application.

[0028] Figure 10 is the structural schematic view of the water inlet and outlet section assembly of the embodiment of the present application.

[0029] Figure 11 is the enlarged structural schematic view of 5A in the embodiment of the present application. Figure 10

[0030] Figure 12 is the sectional structural schematic view of the water inlet and outlet section of the embodiment of the present application.

[0031] Figure 13 is the structural schematic view of the water inlet and outlet section toward the low pressure section side of the embodiment of the present application.

[0032] Figure 14 is the structural schematic view of the water inlet and outlet section toward the high pressure section side of the embodiment of the present application.

[0033] Figure 15 is the sectional structural schematic view of the balance shaft sleeve of the embodiment of the present application.

[0034] Figure 16 is the sectional structural schematic view of the high pressure throttle ring of the embodiment of the present application.

[0035] Figure 17 is the enlarged structural schematic view of 5B in the embodiment of the present application. Figure 11

[0036] Figure 18 is the enlarged structural schematic view of 5C in the embodiment of the present application. Figure 11

[0037] Figure 19 is the structural schematic view of the low pressure throttle ring of the embodiment of the present application.

[0038] Figure 20 is the sectional view of the low pressure section side of the embodiment of the present application.

[0039] Figure 21 is the sectional view of the other side of the low pressure section of the embodiment of the present application.

[0040] Figure 22 is the enlarged structural schematic view of 7A in the embodiment of the present application. Figure 20

[0041] is the sectional view of the high pressure section side of the embodiment of the present application. Figure 23

[0042] is the sectional view of the high pressure section side of the embodiment of the present application.​​​Figure 24 is a cross-sectional view of another side of the high-pressure section of an embodiment of the application.

[0043] Figure 25 is an enlarged structural schematic view of 7B in an embodiment of the application Figure 23

[0044] Figure 26 is an enlarged structural schematic view of 2A in an embodiment of the application Figure 1

[0045] in the figure:

[0046] ​​0001、fluid cavity; 1001, low pressure section; 1002, medium inlet; 1003, first rod; 1007, water inlet section; 1009, low pressure middle section; 1012, low pressure cylinder; 1013, low pressure impeller; 1014, jet channel; 1015, first middle section; 1016, jet passage; 1019, degassing passage; 1020, degassing interface; 1021, low pressure heat exchange cavity; 1022, low pressure heat exchange inlet; 1023, low pressure heat exchange sub-inlet; 1024, first low pressure branch pipe; 1025, low pressure heat exchange outlet; 1026, low pressure heat exchange sub-outlet; 1027, second low pressure branch pipe; 1029, low pressure inner partition plate; 1030, low pressure heat exchange sub-cavity; 2001, high pressure section; 2002, second rod; 2006, secondary water inlet section; 2008, high pressure middle section; 2010, high pressure cavity; 2012, high pressure impeller; 2011, high pressure cylinder; 2015, high pressure heat exchange cavity; 2016, high pressure heat exchange inlet; 2017, high pressure heat exchange sub-inlet; 2018, high pressure heat exchange outlet; 2019, high pressure heat exchange sub-outlet; 2020, high pressure inner partition plate; 2021, high pressure heat exchange sub-cavity; 2022, first high pressure branch pipe; 2023, second high pressure branch pipe; 3000, water inlet and outlet section assembly; 3001, water inlet and outlet section; 3002, medium outlet; 3007, balance cavity; 3008, balance hole; 4001, transition elbow; 4002, transition cylinder; 4003, transition heat exchange cavity; 4004, transition heat exchange inlet; 4005, transition heat exchange outlet; 5001, pump shaft; 5006, flow guide thread; 5007, flow guide inlet; 5008, throttling passage; 5009, throttling ring; 6001, first box; 6002, stabilizing groove; 6008, rotor stabilizing assembly; 6009, first elastic member; 6010, second elastic member; 6011, first bearing; 7001, balance shaft sleeve; 7002, first thrust groove; 7004, high pressure balance flow channel; 7007, resistance flow cavity; 7008, high pressure resistance flow inlet; 7009, high pressure resistance flow outlet; 7010, high pressure shaft end face; 7011, resistance flow inclined face; 7012, first end of inclined face; 7013, second end of inclined face; 7014, high pressure resistance flow thread; 7016, low pressure resistance flow thread; 7017, low pressure resistance flow outlet; 7020, low pressure balance flow channel; 8001, high pressure throttling ring; high pressure ring end face 8002; 9001, low pressure throttling ring; 9004, medium diffusion port; 1501, inducer chamber; 1502, inducer; 1503, inducer suction face; 1504, inducer passage; 1507, jet hole; 1510, degassing cavity; 1511, degassing hole; 1601, mechanical seal seat; 1602, pressure relief passage; 1603, pressure relief pipe; 1604, mechanical seal shaft sleeve; 1605, mechanical seal shaft sleeve ring; 1606, pressure relief cavity; 1701, liquid inlet main pipe; 1702, liquid outlet main pipe; 1703, valve body; 1704, low pressure sub-valve body;1705, high pressure sub-valve body. ; DETAILED DESCRIPTION

[0047] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0048] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0049] In the description of the present invention, it should be understood that the terms "connected," "connected," "fixed," etc. used in the present invention should be interpreted broadly. For example, the terms may be fixedly connected, detachably connected, or integrated; may be mechanically connected or welded; may be directly connected or indirectly connected through an intermediate medium; may be internal communication between two elements or an interactive relationship between two elements, unless otherwise clearly defined. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] like Figures 1 to 26 As shown, a reliable double-casing self-balancing multi-stage centrifugal pump according to a preferred embodiment of the present invention includes a low-pressure section 1001, a high-pressure section 2001, a pump shaft 5001, a pressure relief pipe 1603 and a mechanical seal seat 1601. The low-pressure section 1001 is connected to the high-pressure section 2001 to form a fluid cavity 0001. The mechanical seal seat 1601 is connected to the side of the high-pressure section 2001 away from the low-pressure section 1001. The pump shaft 5001 is respectively provided in the low-pressure section 1001, the high-pressure section 2001 and the mechanical seal seat 1601; the low-pressure section 1001 is provided with a medium inlet 1002 and an inducer chamber 1501, and both ends of the inducer chamber 1501 are respectively connected to the medium inlet 1002 and the fluid cavity 0001. The inducer chamber 1501 is provided with an inducer 1502 connected to the pump shaft 5001;

[0051] The pump shaft 5001 is sleeved with a throttle ring 5009, the throttle ring 5009 is located at one end of the high-pressure section 2001 away from the low-pressure section 1001, the outer periphery of the throttle ring 5009 is provided with a flow guide thread 5006, the flow guide thread 5006 and the high-pressure section 2001 define a throttle channel 5008, the mechanical seal seat 1601 is provided with a pressure relief channel 1602, one end of the throttle channel 5008 is in communication with the fluid cavity 0001, and the other end is in communication with the pressure relief channel 1602, and the pressure relief channel 1602 is in communication with the inducer chamber 1501 through the pressure relief pipe 1603.

[0052] The reliable double-shell self-balancing multi-stage centrifugal pump of the application comprises a low-pressure section 1001, a high-pressure section 2001, a pump shaft 5001, a pressure relief pipe 1603 and a mechanical seal seat 1601, the low-pressure section 1001 is in communication with the high-pressure section 2001 to form a fluid cavity 0001, the mechanical seal seat 1601 is connected to one side of the high-pressure section 2001 away from the low-pressure section 1001, and the pump shaft 5001 is sequentially arranged in the low-pressure section 1001, the high-pressure section 2001 and the mechanical seal seat 1601. The low-pressure section 1001 is provided with a medium inlet 1002 and an inducer chamber 1501, the two ends of the inducer chamber 1501 are in communication with the medium inlet 1002 and the fluid cavity 0001 respectively, and the inducer chamber 1501 is provided with an inducer 1502 connected to the pump shaft 5001, thereby forming an intake and preliminary pressurization path of low-pressure medium. The pump shaft 5001 is sleeved with a throttle ring 5009 located at one end of the high-pressure section 2001 away from the low-pressure section 1001, and the outer periphery of the throttle ring 5009 is provided with a flow guide thread 5006, and the flow guide thread 5006 and the high-pressure section 2001 define a throttle channel 5008; the mechanical seal seat 1601 is provided with a pressure relief channel 1602, one end of the throttle channel 5008 is in communication with the high-pressure section 2001 and the fluid cavity 0001, and the other end is in communication with the pressure relief channel 1602, and the pressure relief channel 1602 is in communication with the inducer chamber 1501 through the pressure relief pipe 1603. The pump shaft 5001 drives the rotation of the throttle ring 5009, and the flow guide thread 5006 structure can actively guide the high-pressure medium in the high-pressure section 2001 to the pressure relief channel 1602, and then to the inducer chamber 1501 through the pressure relief pipe 1603, thereby forming a local high-pressure area near the suction port of the inducer 1502, effectively raising the inlet pressure and preventing cavitation. At the same time, the high-pressure jet flow and the low-pressure medium are mixed in the inducer chamber 1501, thereby enhancing the ejecting effect, driving the low-pressure medium to flow faster, further improving the intake performance, and avoiding cavitation caused by uneven flow rate or insufficient pressure. In addition, the flow guiding effect of the throttle channel 5008 also has a pressure relief effect on the high-pressure section 2001, thereby reducing the impact load of the high-pressure medium on the pump shaft 5001, the bearing and the bearing box, and improving the running stability and service life of the pump.

[0053] Further, as shown in FIG. 1, Figures 1 to 3As shown, the pump shaft 5001 is sleeved with a mechanical seal shaft sleeve 1604, the mechanical seal shaft sleeve 1604 is radially protruding to form a mechanical seal shaft sleeve ring 1605, the mechanical seal shaft sleeve ring 1605, the mechanical seal seat 1601 and the high-pressure section 2001 define a pressure relief cavity 1606, one end of the mechanical seal shaft sleeve 1604 is connected with the throttle ring 5009, one end of the throttle channel 5008 is communicated with the pressure relief cavity 1606, one end of the pressure relief channel 1602 is communicated with the pressure relief cavity 1606. The mechanical seal shaft sleeve ring 1605, the mechanical seal seat 1601 and the high-pressure section 2001 together define an annular space as the pressure relief cavity 1606. It is one of the key structures to realize the self-balancing pressure relief and sealing protection function of the multi-stage centrifugal pump. The pressure relief cavity 1606 connects the throttle channel 5008 and the pressure relief channel 1602, and constitutes a flow path of the high-pressure medium from the high-pressure section 2001, the throttle channel 5008, the pressure relief cavity 1606, the pressure relief channel 1602 and the inducer chamber 1501. The pressure relief cavity 1606 plays a buffering role, can stabilize the flow of high-pressure medium from the drainage thread structure 5006, and prevent pressure from suddenly changing; the pressure relief cavity 1606 plays a transition role, realizes the continuous flow and path guidance of the pressure relief medium, improves the stability and controllability of the pressure relief system, and further improves the operation stability and reliability of the pump under complex working conditions such as high pressure and high temperature.

[0054] Further, as Figures 1 to 3As shown, the high-pressure section 2001 includes a high-pressure impeller 2012, a high-pressure middle section 2008, and a secondary water inlet section 2006, the low-pressure section 1001, the high-pressure middle section 2008, and the secondary water inlet section 2006 define a fluid cavity 0001, the high-pressure impeller 2012 is connected to the pump shaft 5001 and located in the high-pressure middle section 2008, the secondary water inlet section 2006 is connected to the high-pressure middle section 2008 away from the low-pressure section 1001, the secondary water inlet section 2006 is connected to the high-pressure middle section 2008 between the mechanical seal seat 1601 and the mechanical seal shaft sleeve ring 1605, the secondary water inlet section 2006 communicates with the low-pressure section 1001, the throttle ring 5009 and the secondary water inlet section 2006 define a throttling passage 5008, the throttling passage 5008 is provided with a flow guide inlet 5007, the flow guide inlet 5007 is located on the side of the secondary water inlet section 2006 facing the high-pressure middle section 2008, and the other end of the secondary water inlet section 2006 and the mechanical seal seat 1601 and the mechanical seal shaft sleeve ring 1605 define a pressure relief cavity 1606. The low-pressure section 1001, the high-pressure middle section 2008, and the secondary water inlet section 2006 together define a fluid cavity 0001, the high-pressure impeller 2012 is connected to the pump shaft 5001 and located in the high-pressure middle section 2008, the secondary water inlet section 2006 is connected to the high-pressure middle section 2008 away from the low-pressure section 1001, and forms a throttling passage 5008 and a pressure relief cavity 1606 between the high-pressure middle section 2008 and the mechanical seal seat 1601. The throttling passage 5008 is provided with a flow guide inlet 5007 located on the side of the secondary water inlet section 2006 facing the high-pressure middle section 2008 for efficient flow of the high-pressure section 2001 medium; the other end of the secondary water inlet section 2006 and the mechanical seal seat 1601 and the mechanical seal shaft sleeve ring 1605 together define a pressure relief cavity 1606 as a buffer and transition area for high-pressure medium. The integrated arrangement of the secondary water inlet section 2006 realizes the modularization and compactness of the high-pressure section 2001 structure, and improves the flow efficiency of the throttling passage 5008 and the stability of the pressure relief system. After the high-pressure medium enters the pressure relief cavity 1606 through the throttling passage 5008, it can be further transported to the inducer chamber 1501 through the pressure relief passage 1602, and a local high-pressure area is formed near the suction inlet of the inducer 1502, effectively preventing cavitation.

[0055] Further, as Figures 4 to 9As shown, the inducer chamber 1501 is provided with a jet hole 1507, the inducer 1502 is provided with an inducer suction surface 1503 on one side of the low pressure section 1001, the low pressure section 1001 is provided with a jet channel 1016 communicating with the pressure relief pipe 1603, one end of the jet hole 1507 communicates with the jet channel 1016, and the other end of the jet hole 1507 is arranged towards the inducer suction surface 1503. The low pressure section 1001 is provided with the jet channel 1016, the jet channel 1016 communicates with the inducer chamber 1501, the jet channel 1016 is a channel for the high pressure medium to enter the inducer chamber 1501, the jet hole 1507 respectively communicates with the jet channel 1016 and the inducer chamber 1501, and the jet hole 1507 is arranged towards the inducer suction surface 1503 to form a jet anti-cavitation system, so that the high pressure medium after passing through the pressure relief channel 1602, the pressure relief pipe 1603 and the jet channel 1016, directly acts on the suction surface of the inducer 1502 in the form of high-speed jet, improves the pressure level of the region, and reduces the necessary cavitation margin of the pump. At the same time, when the jet is sprayed towards the suction surface, the low pressure medium in the water inlet section 1007 is accelerated to flow, effectively preventing the cavitation phenomenon caused by uneven flow rate or insufficient pressure, improving the suction performance at the start-up stage of the pump, and improving the operation reliability and service life of the multi-stage centrifugal pump.

[0056] Further, as shown in the figure, Figures 4 to 9 As shown, the low pressure section 1001 includes a water inlet section 1007 and a first stage middle section 1015, the first stage middle section 1015 is connected to one side of the water inlet section 1007 towards the high pressure section 2001, the medium inlet 1002 is arranged in the water inlet section 1007, the inducer chamber 1501 is connected in the first stage middle section 1015, one side of the water inlet section 1007 towards the first stage middle section 1015 is provided with an inducer mounting port, the inducer chamber 1501 is provided with a jet hole 1507 and an inducer channel 1504 extending in the axial direction, the inducer 1502 is located in the inducer channel 1504, both ends of the inducer channel 1504 respectively communicate with the medium inlet 1002 and the fluid cavity 0001, and the jet hole 1507 respectively communicates with the jet channel 1016 and the inducer channel 1504. The medium inlet 1002 is arranged in the water inlet section 1007, and the medium enters the inducer chamber 1501 from the water inlet section 1007. The first stage middle section 1015 is connected with the water inlet section 1007 to realize fixation, the water inlet section 1007 is provided with the inducer mounting port, one end of the inducer chamber 1501 is connected to the inducer mounting port, and the other end is connected in the first stage middle section 1015 to realize fixation of the inducer chamber 1501. At the same time, the inducer chamber 1501 communicates with the medium inlet 1002 of the water inlet section 1007 through the inducer mounting port. The inducer channel 1504 is the main flow path of the medium from the medium inlet 1002 to the fluid cavity 0001, and extends in the axial direction, which is conducive to smooth flow of the medium. The inducer 1502 is located in the inducer channel 1504, so that it coincides with the jet action area to improve the synergistic effect.

[0057] As one of the embodiments, as shown in Figures 4 to 9 The water inlet section 1007 is provided with a jet groove 1014, which is arranged around the induction installation port. The induction wheel chamber 1501 is connected to the opening of the jet groove 1014. The jet hole 1507 is provided with a plurality of jet holes 1507, which are arranged along the circumference of the induction wheel chamber 1501 and are respectively communicated with the jet groove 1014. The jet channel 1016 is provided with a plurality of jet channels 1016, which are arranged along the circumference of the water inlet section 1007 and are communicated with the jet groove 1014. The annular structure of the jet groove 1014 arranged around the induction installation port provides a unified high-pressure medium distribution channel for the plurality of jet holes 1507. The induction wheel chamber 1501 is connected to the opening side of the jet groove 1014, and a sealed connection is formed between the induction wheel chamber 1501 and the jet groove 1014, so that the jet groove 1014 forms a sealed annular channel. The high-pressure medium in the plurality of jet channels 1016 enters the annular jet groove 1014 and then enters the induction wheel chamber 1501 from the plurality of jet holes 1507, respectively, to ensure that the high-pressure medium can only enter the induction channel 1504 through the jet hole 1507, thereby improving the sealing and efficiency of the system. The plurality of jet holes 1507 are arranged along the circumference of the induction wheel chamber 1501, which realizes more uniform jet coverage and enhances the pressure boosting effect near the suction surface 1503 of the induction wheel. The plurality of jet channels 1016 are respectively communicated with the discharge pipe, and the plurality of jet channels 1016 respectively introduce high-pressure medium from the discharge pipe 1603 to the jet groove 1014, forming a multi-point energy supply path, which improves the flow stability and response speed.

[0058] Further, as shown in Figures 4 to 9As shown, the low-pressure section 1001 further comprises a low-pressure middle section 1009, the first-stage middle section 1015 is connected between the water inlet section 1007 and the low-pressure middle section 1009, the end of the inducer chamber 1501 away from the water inlet section 1007 is in communication with the low-pressure middle section 1009, the low-pressure impeller 1013 is connected to the pump shaft 5001, the low-pressure impeller 1013 is located on the side of the low-pressure middle section 1009 facing the inducer chamber 1501, the inducer chamber 1501 and the first-stage middle section 1015 define a degassing cavity 1510, the inducer chamber 1501 is provided with a degassing hole 1511, the degassing hole 1511 is arranged towards the low-pressure impeller 1013, the degassing cavity 1510 is in communication with the inducer chamber 1501 through the degassing hole 1511, the water inlet section 1007 is provided with a degassing passage 1019 for communication with a degassing device, the degassing passage 1019 is in communication with the degassing cavity 1510 to form a degassing anti-cavitation system. The jet groove 1014 is arranged in an annular structure around the inducer mounting port, and provides a unified high-pressure medium distribution channel for the plurality of jet holes 1507. The inducer chamber 1501 is connected to the opening side of the jet groove 1014, and a sealed connection is formed between the inducer chamber 1501 and the jet groove 1014, so that the jet groove 1014 forms a sealed annular channel, and the high-pressure medium in the plurality of jet channels 1016 enters the annular jet groove 1014 and then enters the inducer chamber 1501 from the plurality of jet holes 1507, respectively, to ensure that the high-pressure medium can only enter the inducer channel 1504 through the jet hole 1507, thereby improving the system sealing performance and efficiency. The plurality of jet holes 1507 are arranged in a circumferential direction of the inducer chamber 1501, so as to achieve more uniform jet coverage and enhance the pressure boosting effect near the inducer suction surface 1503. The plurality of jet channels 1016 are respectively in communication with the drain pipes, the plurality of jet channels 1016 respectively introduce high-pressure medium from the pressure relief pipes 1603 to the jet groove 1014, form a multi-point energy supply path, and improve the flow stability and response speed.

[0059] As an embodiment, the water inlet section 1007 is provided with a degassing interface 1020, and the degassing interface 1020 is in communication with the degassing passage 1019. The degassing interface 1020 is used to connect a degassing device. The degassing anti-cavitation system and the jet anti-cavitation system form a double high anti-cavitation system.

[0060] Further, as Figures 20 to 25As shown, the reliable double-shell self-balancing multi-stage centrifugal pump further comprises a liquid inlet main pipe 1701, a liquid outlet main pipe 1702, a transition elbow 4001, a pump shaft 5001, and a low-pressure section 1001, an inlet and outlet water section 3001, and a high-pressure section 2001 which are respectively sleeved on the pump shaft 5001, the low-pressure section 1001 is provided with a medium inlet 1002, the inlet and outlet water section 3001 is provided with a medium outlet 3002, the inlet and outlet water section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001, the low-pressure section 1001 is communicated with one end of the transition elbow 4001 through the inlet and outlet water section 3001, and the other end is communicated with one end of the high-pressure section 2001 away from the inlet and outlet water section 3001, the high-pressure section 2001 is communicated with the inlet and outlet water section 3001 to form a fluid cavity 0001,

[0061] The outer periphery of the low-pressure section 1001 is sleeved with a low-pressure cylinder 1012, and the low-pressure cylinder 1012 and the low-pressure section 1001 define a low-pressure heat exchange cavity 1021, which is provided with a low-pressure heat exchange inlet 1022 and a low-pressure heat exchange outlet 1025. The outer periphery of the high-pressure section 2001 is sleeved with a high-pressure cylinder 2011, and the high-pressure cylinder 2011 and the high-pressure section 2001 define a high-pressure heat exchange cavity 2015, which is provided with a high-pressure heat exchange inlet 2016 and a high-pressure heat exchange outlet 2018. The low-pressure heat exchange inlet 1022 and the high-pressure heat exchange inlet 2016 are respectively communicated with the liquid inlet main pipe 1701, and the low-pressure heat exchange outlet 1025 and the high-pressure heat exchange outlet 2018 are respectively communicated with the liquid outlet main pipe 1702. The low-pressure heat exchange inlet 1022, the low-pressure heat exchange outlet 1025, the high-pressure heat exchange inlet 2016 and the high-pressure heat exchange outlet 2018 are respectively connected with valve bodies 1703. The low-pressure section 1001 is provided with a medium inlet 1002, and the water inlet and outlet section 3001 is provided with a medium outlet 3002. The medium enters from the medium inlet 1002 and is output from the medium outlet 3002. The water inlet and outlet section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001 and is connected with the low-pressure section 1001 and the high-pressure section 2001 respectively. The low-pressure section 1001 is communicated with the high-pressure section 2001 through a transition elbow 4001, so as to realize the medium transmission between the stages of the multi-stage pump and ensure the continuous pressurization capacity of the pump. The outer periphery of the low-pressure section 1001 is provided with the low-pressure cylinder 1012, which defines the low-pressure heat exchange cavity 1021 with the low-pressure section 1001, so as to control the heat exchange space of the low-pressure section 1001 and realize the temperature control of the low-pressure section 1001. The outer periphery of the high-pressure section 2001 is provided with the high-pressure cylinder 2011, which defines the high-pressure heat exchange cavity 2015 with the high-pressure section 2001, so as to control the heat exchange space of the high-pressure section 2001 and realize the temperature control of the high-pressure section 2001. The low-pressure heat exchange inlet 1022 and the high-pressure heat exchange inlet 2016 are respectively communicated with the liquid inlet main pipe 1701, so as to provide a unified heat exchange medium inlet 1002 and realize the centralized control of the heat exchange system. The low-pressure heat exchange outlet 1025 and the high-pressure heat exchange outlet 2018 are respectively communicated with the liquid outlet main pipe 1702, so as to realize the unified recovery and recycling of the heat exchange medium and improve the heat exchange efficiency and system integration. The low-pressure heat exchange inlet 1022, the low-pressure heat exchange outlet 1025, the high-pressure heat exchange inlet 2016 and the high-pressure heat exchange outlet 2018 are respectively connected with the valve bodies 1703, so as to control the flow and on-off of the heat exchange medium and realize the step-by-step regulation to achieve the accurate temperature control of different regions of the pump cavity. The low-pressure heat exchange cavity 1021 and the high-pressure heat exchange cavity 2015 are independent of each other, which can independently adjust the flow and temperature of the heat exchange medium according to the temperature requirements of the respective regions. The liquid inlet main pipe 1701 and the liquid outlet main pipe 1702 are connected uniformly, which is convenient for centralized control and improves the system integration. The valve bodies 1703 control so that each low-pressure heat exchange cavity 1021 and high-pressure heat exchange cavity 2015 can flexibly adjust the heat exchange strategy according to the operating state (start, run, stop).The heat exchange cavity structure and the pump body structure are highly integrated, reducing the influence on the main function operation of the pump, and then realizing the temperature control of the pump cavity through the hierarchical heat exchange structure, preventing structural deformation, and improving the operation reliability.

[0062] As one of the embodiments, as shown in Figures 20 to 25 The outer periphery of the transition elbow pipe 4001 is sleeved with a transition cylinder body 4002, and the transition cylinder body 4002 and the transition elbow pipe 4001 define a transition heat exchange cavity 4003. The transition heat exchange cavity 4003 is provided with a transition heat exchange inlet 4004 connected with a valve body 1703 and a transition heat exchange outlet 4005. The transition heat exchange inlet 4004 is in communication with the liquid inlet main pipe 1701, and the transition heat exchange outlet 4005 is in communication with the liquid outlet main pipe 1702. The outer periphery of the transition elbow pipe 4001 is sleeved with the transition cylinder body 4002, and the transition cylinder body 4002 and the transition elbow pipe 4001 jointly define the transition heat exchange cavity 4003. The transition heat exchange cavity 4003 is provided with the transition heat exchange inlet 4004 connected with the valve body 1703 and the transition heat exchange outlet 4005. The transition heat exchange inlet 4004 is in communication with the liquid inlet main pipe 1701, and the transition heat exchange outlet 4005 is in communication with the liquid outlet main pipe 1702, realizing independent temperature control in the transition elbow pipe 4001 region, filling the temperature control blank between the low-pressure section 1001 and the high-pressure section 2001, and forming a complete temperature control link from the low-pressure section 1001, the transition section, and the high-pressure section 2001. Through the independent control of the transition heat exchange cavity 4003, the temperature demand under different working conditions can be more flexibly responded to, ensuring that the pump always maintains a stable temperature environment during startup, operation, and shutdown, avoiding structural deformation or performance degradation caused by thermal expansion and contraction.

[0063] As one of the embodiments, as shown in Figures 20 to 25 The high-pressure heat exchange cavity 2015, the low-pressure heat exchange cavity 1021, and the transition heat exchange cavity 4003 form the cavity hierarchical pressure maintaining heat exchange function of the pump, so that the pump cavity can accurately and fully realize the cooling, heat preservation, and heating capacity, eliminate the expansion and contraction deformation of the pump cavity and other components, and ensure the reliable and safe operation of the multi-stage pump.

[0064] As one of the embodiments, as shown in Figures 20 to 25As shown, the low-pressure section 1001 includes a water inlet section 1007 and a low-pressure middle section 1009, the medium inlet 1002 is arranged at the water inlet section 1007, the low-pressure middle section 1009 is located between the water inlet section 1007 and the water inlet and outlet section 3001, the low-pressure cylinder 1012 is sleeved on the outer periphery of the low-pressure middle section 1009, both ends of the low-pressure cylinder 1012 are sealingly connected with the water inlet section 1007 and the water inlet and outlet section 3001 respectively, and the low-pressure middle section 1009 is in communication with the transition bend 4001 through the water inlet and outlet section 3001. The water inlet section 1007 is provided with the medium inlet 1002, so as to ensure that the medium can enter the low-pressure section 1001 and flow to the water inlet and outlet section 3001 through the low-pressure middle section 1009. The low-pressure cylinder 1012 is sleeved on the outer periphery of the low-pressure middle section 1009 to form a low-pressure heat exchange cavity 1021, so that the heat exchange medium can uniformly cover the surface of the low-pressure section 1001, thereby improving the heat exchange efficiency. The both ends of the low-pressure cylinder 1012 are sealingly connected with the water inlet section 1007 and the water inlet and outlet section 3001, so as to ensure the sealing property of the low-pressure heat exchange cavity 1021 and prevent mutual pollution between the heat exchange medium and the pumping medium, thereby ensuring the normal operation of the system.

[0065] As one of the embodiments, as shown in FIG. 1, the heat exchange system 1000 includes a low-pressure section 1001 and a high-pressure section 2001, the low-pressure section 1001 is connected with the high-pressure section 2001 through a transition bend 4001, and the transition bend 4001 is connected with the low-pressure section 1001 through a water inlet and outlet section 3001. Figures 20 to 25As shown, the low-pressure cylinder 1012 is provided with a low-pressure inner partition plate 1029 located in the low-pressure heat exchange cavity 1021. The low-pressure inner partition plate 1029 is connected with the low-pressure middle section 1009. The low-pressure inner partition plate 1029 separates the low-pressure heat exchange cavity 1021 into a plurality of low-pressure heat exchange sub-cavities 1030 that are isolated from each other. The low-pressure heat exchange inlet 1022 includes a plurality of low-pressure heat exchange sub-inlets 1023, and the low-pressure heat exchange outlet 1025 includes a plurality of low-pressure heat exchange sub-outlets 1026. The valve body 1703 includes a plurality of low-pressure sub-valve bodies 1704. Each low-pressure heat exchange sub-cavity 1030 is respectively provided with a low-pressure heat exchange sub-inlet 1023 and a low-pressure heat exchange sub-outlet 1026. The low-pressure heat exchange sub-inlet 1023 is connected with a first low-pressure branch pipe 1024, and the first low-pressure branch pipe 1024 is in communication with the liquid inlet main pipe 1701. The low-pressure heat exchange sub-outlet 1026 is connected with a second low-pressure branch pipe 1027, and the second low-pressure branch pipe 1027 is in communication with the liquid outlet main pipe 1702. The first low-pressure branch pipe 1024 and the second low-pressure branch pipe 1027 are respectively connected with a low-pressure sub-valve body 1704. The low-pressure inner partition plate 1029 separates the low-pressure heat exchange cavity 1021 into a plurality of independent low-pressure heat exchange sub-cavities 1030. Each low-pressure heat exchange sub-cavity 1030 has an independent low-pressure heat exchange sub-inlet 1023 and a low-pressure heat exchange sub-outlet 1026, and is in communication with the liquid inlet main pipe 1701 and the liquid outlet main pipe 1702 through the respective first low-pressure branch pipe 1024 and the second low-pressure branch pipe 1027. Each low-pressure heat exchange sub-cavity 1030 is equipped with an independent low-pressure sub-valve body 1704 for controlling the flow and on-off of the heat exchange medium. Each low-pressure heat exchange sub-cavity 1030 can be independently temperature-regulated, which improves the flexibility and controllability of the system and effectively avoids structural deformation or performance degradation caused by uneven local temperature. The low-pressure heat exchange sub-cavities 1030 work independently, so that even if a certain low-pressure heat exchange sub-cavity 1030 fails, it will not affect the normal operation of other low-pressure heat exchange sub-cavities 1030, thereby improving the reliability of the system.

[0066] As one of the embodiments, as Figures 20 to 25As shown, the low-pressure section 1001 is provided with a first rod body 1003 extending in the same direction as the pump shaft 5001, and the low-pressure section 1001 is connected to the water inlet and outlet section 3001 through the first rod body 1003. The low-pressure section 1001 is connected to the water inlet and outlet section 3001 through the first rod body 1003 to form a first assembly part, and the cumulative error of each assembly part is controlled within a local range to avoid error accumulation. The water inlet and outlet section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001, and the water inlet and outlet section 3001 serves as an intermediate reference part. During assembly, the water inlet and outlet section 3001 is fixed first, then the low-pressure section 1001 is connected through the first rod body 1003, and then the high-pressure section 2001 is assembled to form an assembly logic with the intermediate reference part at both ends. This reduces the difficulty of traditional multi-stage pump alignment and ensures the assembly coaxiality of the low-pressure section 1001, the high-pressure section 2001 and the water inlet and outlet section 3001. The low-pressure section 1001 is rigidly connected to the water inlet and outlet section 3001 through the first rod body 1003, and the axial force is transmitted to the water inlet and outlet section 3001 to avoid force concentration on the pump shaft 5001, reduce vibration and wear, and ensure reliable and safe operation of the multi-stage pump.

[0067] As one of the embodiments, as shown in Figures 20 to 25 The high-pressure section 2001 includes a secondary water inlet section 2006 and a high-pressure middle section 2008. The high-pressure middle section 2008 is located between the secondary water inlet section 2006 and the water inlet and outlet section 3001. The high-pressure cylinder 2011 is sleeved on the outer periphery of the high-pressure middle section 2008, and the two ends of the high-pressure cylinder 2011 are sealingly connected to the secondary water inlet section 2006 and the water inlet and outlet section 3001, respectively. The sealing connection of the two ends of the high-pressure cylinder 2011 to the secondary water inlet section 2006 and the water inlet and outlet section 3001 ensures the sealing of the high-pressure heat exchange cavity 2015, prevents mutual contamination between the heat exchange medium and the pumping medium, and ensures the normal operation of the system. The secondary water inlet section 2006 communicates with the transition bend pipe 4001, and the transition bend pipe 4001 communicates with the side of the secondary water inlet section 2006 away from the high-pressure middle section 2008, forming a complete medium flow path from the low-pressure section 1001 to the high-pressure section 2001, and improving the overall performance of the pump.

[0068] As one of the embodiments, as shown in Figures 23 to 25As shown, the high-pressure cylinder 2011 is provided with a high-pressure inner partition plate 2020 located in the high-pressure heat exchange cavity 2015. The high-pressure inner partition plate 2020 is connected with the high-pressure middle section 2008. The high-pressure inner partition plate 2020 separates the high-pressure heat exchange cavity 2015 into a plurality of high-pressure heat exchange sub-cavities 2021 that are isolated from each other. The high-pressure heat exchange inlet 2016 includes a plurality of high-pressure heat exchange sub-inlets 2017, and the high-pressure heat exchange outlet 2018 includes a plurality of high-pressure heat exchange sub-outlets 2019. The valve body 1703 includes a plurality of high-pressure sub-valve bodies 1705. Each high-pressure heat exchange sub-cavity 2021 is respectively provided with a high-pressure heat exchange sub-inlet 2017 and a high-pressure heat exchange sub-outlet 2019. The high-pressure heat exchange sub-inlet 2017 is connected with a first high-pressure branch pipe 2022, and the first high-pressure branch pipe 2022 is in communication with the liquid inlet main pipe 1701. The high-pressure heat exchange sub-outlet 2019 is connected with a second high-pressure branch pipe 2023, and the second high-pressure branch pipe 2023 is in communication with the liquid outlet main pipe 1702. The first high-pressure branch pipe 2022 and the second high-pressure branch pipe 2023 are respectively connected with the high-pressure sub-valve body 1705. The high-pressure heat exchange cavity 2015 is separated into a plurality of independent high-pressure heat exchange sub-cavities 2021 by the high-pressure inner partition plate 2020, so that the heat exchange medium can more evenly cover the surface of the high-pressure section 2001, thereby improving the heat exchange efficiency. Each high-pressure heat exchange sub-cavity 2021 is provided with an independent high-pressure heat exchange sub-inlet 2017, a high-pressure heat exchange sub-outlet 2019, and a high-pressure sub-valve body 1705, which can flexibly adjust the flow and temperature of the heat exchange medium according to actual needs, thereby avoiding structural deformation or performance degradation caused by uneven local temperature. In addition, the independently controlled high-pressure heat exchange sub-cavities 2021 can precisely regulate the temperature of each high-pressure heat exchange sub-cavity 2021 during different stages such as starting, running, and stopping, thereby improving the overall controllability and adaptability of the system.

[0069] As one embodiment, as shown in FIG. 1, the heat exchange system 100 includes a heat exchange cavity 101, a liquid inlet main pipe 102, a liquid outlet main pipe 103, a valve body 104, a heat exchange medium 105, and a heat exchange medium supply device 106. Figures 23 to 25As shown, the high-pressure section 2001 is provided with a second rod body 2002 extending in the same direction as the pump shaft 5001, and the high-pressure section 2001 is connected with the water inlet and outlet section 3001 through the second rod body 2002. The high-pressure section 2001 is connected with the water inlet and outlet section 3001 through the second rod body 2002 to form a second assembly part, so that the cumulative error of each assembly part is controlled within a local range, and the error is avoided from being superimposed. The water inlet and outlet section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001, and the water inlet and outlet section 3001 serves as an intermediate reference part. In assembly, the water inlet and outlet section 3001 is first fixed, then the water inlet and outlet section 3001 is connected with the low-pressure section 1001, and then the water inlet and outlet section 3001 and the high-pressure section 2001 are assembled through the second rod body 2002 to form an assembly logic of fixing two ends by an intermediate reference part. The assembly logic reduces the difficulty of traditional multi-stage pump step-by-step alignment, and ensures the assembly coaxiality of the low-pressure section 1001, the high-pressure section 2001 and the water inlet and outlet section 3001. The high-pressure section 2001 is rigidly connected with the water inlet and outlet section 3001 through the second rod body 2002, the axial force is transmitted to the water inlet and outlet section 3001, the force is avoided from being concentrated on the pump shaft 5001, the vibration and wear are reduced, and the reliable and safe operation of the multi-stage pump is ensured.

[0070] As one of the embodiments, as shown in Figures 20 to 25 The low-pressure section 1001 is connected with the water inlet and outlet section 3001 through the first rod body 1003 to form a first assembly part, and the high-pressure section 2001 is connected with the water inlet and outlet section 3001 through the second rod body 2002 to form a second assembly part. The first assembly part and the second assembly part form a stable function of grading the cavity of the pump, so that the pump cavity can be accurately positioned and matched, the concentricity of assembly and operation is ensured, the expansion, contraction and sagging deformation of the pump cavity and other parts are eliminated, and the reliable and safe operation of the multi-stage pump is ensured.

[0071] Further, as shown in Figures 10 to 19 The water inlet and outlet section assembly 3000 is located between the low-pressure section 1001 and the high-pressure section 2001, the pump shaft 5001 is coaxially arranged in the low-pressure section 1001, the water inlet and outlet section assembly 3000 and the high-pressure section 2001, the low-pressure section 1001 is communicated with one end of the transition elbow 4001 through the water inlet and outlet section assembly 3000, and the other end of the transition elbow 4001 is communicated with the end of the high-pressure section 2001 away from the water inlet and outlet section 3001.

[0072] The inlet and outlet water section assembly 3000 is provided with a balance cavity 3007, a balance hole 3008, a medium outlet 3002 and a high-pressure resistance flow inlet 7008. The medium outlet 3002 and the high-pressure resistance flow inlet 7008 are respectively communicated with the high-pressure section 2001. The high-pressure resistance flow inlet 7008 is located between the pump shaft 5001 and the medium outlet 3002. The high-pressure resistance flow inlet 7008 is communicated with the balance cavity 3007. The balance cavity 3007 is communicated with the transition elbow 4001 through the balance hole 3008. The low-pressure section 1001, the inlet and outlet water section assembly 3000, the transition elbow 4001 and the high-pressure section 2001 are connected to form a complete fluid cavity 0001. The medium enters the fluid cavity 0001 from the medium inlet 1002 of the low-pressure section 1001. The pump shaft 5001 is arranged in the low-pressure section 1001, the inlet and outlet water section assembly 3000 and the high-pressure section 2001 respectively and drives the impeller in the low-pressure section 1001 and the high-pressure section 2001 to rotate to pressurize the medium in the fluid cavity 0001. The inlet and outlet water section assembly 3000 is provided with a balance cavity 3007, a balance hole 3008, a medium outlet 3002 and a high-pressure resistance flow inlet 7008. The medium outlet 3002 and the high-pressure resistance flow inlet 7008 are respectively communicated with the high-pressure section 2001. The high-pressure resistance flow inlet 7008 is located between the pump shaft 5001 and the medium outlet 3002. Most of the high-pressure medium of the high-pressure section 2001 flows out from the medium outlet 3002. The high-pressure medium enters the balance cavity 3007 through the high-pressure resistance flow inlet 7008. The high-pressure resistance flow inlet 7008, the balance cavity 3007 and the balance hole 3008 form a pressure regulating path. After the high-pressure medium of the high-pressure section 2001 enters the balance cavity 3007 through the high-pressure resistance flow inlet 7008, the balance cavity 3007 acts as a pressure buffer container and absorbs pressure pulsation through its volume effect. The high-pressure medium in the balance cavity 3007 diffuses and depressurizes through the balance hole 3008 and finally flows back to the high-pressure section 2001 through the transition elbow 4001, reducing the effect of residual axial force on the impeller of the low-pressure section 1001, thereby realizing the regulation of residual axial force of the multi-stage centrifugal pump and ensuring the reliable and safe operation of the multi-stage pump.

[0073] As one of the embodiments, as shown in the figure, a plurality of low-pressure impellers 1013 are arranged in the low-pressure section 1001, the low-pressure impellers 1013 are arranged in the low-pressure cavity of the low-pressure section 1001, a plurality of high-pressure impellers 2012 are arranged in the high-pressure section 2001, the high-pressure impellers 2012 are arranged in the high-pressure cavity 2010 of the high-pressure section 2001, the low-pressure impellers 1013 and the high-pressure impellers 2012 are coaxially connected to the pump shaft 5001, the plurality of low-pressure impellers 1013 and the plurality of high-pressure impellers 2012 are arranged along the pump shaft 5001, the rotation directions of the low-pressure impellers 1013 and the high-pressure impellers 2012 are opposite. The low-pressure impellers 1013 and the high-pressure impellers 2012 are prior art, as long as the impellers can pressurize the medium. The medium is pressurized step by step by the low-pressure impellers 1013 and the high-pressure impellers 2012, and the step-by-step pressurization of the medium by the low-pressure impellers 1013 and the high-pressure impellers 2012 is prior art. The low-pressure impellers 1013 and the high-pressure impellers 2012 are fixedly connected to the pump shaft 5001, the motor is connected to the pump shaft 5001 to drive the pump shaft 5001 to rotate, the low-pressure impellers 1013 are driven to rotate in the low-pressure section 1001 by the pump shaft 5001, and the high-pressure impellers 2012 are driven to rotate in the high-pressure section 2001 by the pump shaft 5001.

[0074] Further, as shown in the figure, Figures 10 to 19 The inlet and outlet section assembly 3000 includes an inlet and outlet section 3001, a balance shaft sleeve 7001, and a high-pressure throttle ring 8001. The two ends of the inlet and outlet section 3001 are connected to the low-pressure section 1001 and the high-pressure section 2001, respectively. The balance cavity 3007, the balance hole 3008, and the medium outlet 3002 are arranged on the inlet and outlet section 3001. The high-pressure throttle ring 8001 is connected to one side of the inlet and outlet section 3001 facing the high-pressure section 2001. The balance shaft sleeve 7001 is arranged on the outer periphery of the pump shaft 5001. The high-pressure throttle ring 8001 is arranged on one end of the balance shaft sleeve 7001 facing the high-pressure section 2001. The high-pressure throttle ring 8001 and the balance shaft sleeve 7001 define a high-pressure flow resistance inlet 7008. The other end of the high-pressure throttle ring 8001 is located in the balance cavity 3007. The high-pressure throttle ring 8001 is connected to the inlet and outlet section 3001 to fix the high-pressure throttle ring 8001. The balance shaft sleeve 7001 is arranged on the outer periphery of the pump shaft 5001 and is driven to rotate synchronously by the pump shaft 5001. The high-pressure throttle ring 8001 and the balance shaft sleeve 7001 define a high-pressure flow resistance inlet 7008, which can guide part of the high-pressure medium flowing out of the high-pressure section 2001 into the balance cavity 3007. The other end of the high-pressure throttle ring 8001 is located in the balance cavity 3007, so that the high-pressure medium flows smoothly between the balance shaft sleeve 7001 and the high-pressure throttle ring 8001 into the balance cavity 3007 for pressure buffering, enhancing the controllability of the high-pressure medium flow path.

[0075] As one of the embodiments, as shown in the figure, Figures 10 to 19As shown, the water inlet and outlet sections 3001 are connected to the low-pressure middle section 1009 and the high-pressure middle section 2008 at both ends of the axial direction.

[0076] As one embodiment, Figures 10 to 19 As shown, the outer periphery of the balancing sleeve 7001 is provided with high-pressure choke threads 7014, which are positioned correspondingly to the position of the high-pressure throttle ring 8001. When the pump shaft 5001 drives the balancing sleeve 7001 to rotate synchronously, the high-pressure choke threads 7014 guide and promote the high-pressure medium flowing into the balancing chamber 3007 from the high-pressure choke inlet 7008, effectively preventing the backflow of the high-pressure medium and enhancing the controllability of the high-pressure medium flow path.

[0077] As one embodiment, Figures 10 to 19 As shown, a first thrust groove 7002 is provided on the end surface of the balancing sleeve 7001 facing the high-pressure section 2001. The end of the balancing sleeve 7001 facing the low-pressure section 1001 abuts the pump shaft 5001. The opening of the first thrust groove 7002 faces the high-pressure section 2001. The high-pressure section 2001 includes a high-pressure cavity 2010 for pressurized fluid. A high-pressure balancing channel 7004 is provided between the water inlet and outlet sections 3001 and the high-pressure section 2001. The high-pressure balancing channel 7004 communicates with the high-pressure cavity 2010, and the first thrust groove 7002 connects with the high-pressure balancing channel 7004. The high-pressure balancing channel 7004 connects the high-pressure cavity 2010 with the first thrust groove 7002. The high-pressure medium in the high-pressure section 2001 enters the first thrust groove 7002 through the high-pressure balancing channel 7004, pushing the balancing sleeve 7001 toward the low-pressure side, positioning it with the pump shaft 5001 and achieving axial positioning. The balancing sleeve 7001 is automatically positioned using high-pressure fluid, eliminating the need for external adjustment mechanisms. The continuous action of the high-pressure fluid dynamically balances the axial forces 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.

[0078] Further, such as Figures 10 to 19As shown, the water inlet and outlet section assembly 3000 further comprises a low-pressure throttling ring 9001 connected to one side of the water inlet and outlet section 3001 facing the low-pressure section 1001, the low-pressure throttling ring 9001 is sleeved on one end of the balance shaft sleeve 7001 facing the low-pressure section 1001, one end of the low-pressure throttling ring 9001 is located in the balance cavity 3007, and the low-pressure throttling ring 9001 and the high-pressure throttling ring 8001 define a medium diffusion port 9004 therebetween, the other end of the low-pressure throttling ring 9001 and the balance shaft sleeve 7001 define a low-pressure throttling outlet 7017 therebetween, and the low-pressure throttling outlet 7017 communicates with the transition bend 4001. The low-pressure throttling ring 9001 is connected to the water inlet and outlet section 3001 to fix the low-pressure throttling ring 9001. The high-pressure medium first enters the gap between the high-pressure throttling ring 8001 and the balance shaft sleeve 7001 from the high-pressure throttling inlet 7008 and flows in the direction of the pump shaft 5001. Part of the high-pressure medium flows into the balance cavity 3007 through the medium diffusion port 9004, and after pressure buffering in the balance cavity 3007, enters the transition bend 4001 through the balance hole 3008; when the flow of the high-pressure medium is large, the rest continues to flow in the direction of the pump shaft 5001, enters the gap between the low-pressure throttling ring 9001 and the balance shaft sleeve 7001, and finally flows into the transition bend 4001 through the low-pressure throttling outlet 7017. The arrangement of the medium diffusion port 9004 enables the high-pressure medium to be preliminarily dispersed when entering the balance cavity 3007, and when the flow of the high-pressure medium is large, the communication between the low-pressure throttling outlet 7017 and the transition bend 4001 ensures that the high-pressure medium can be timely diverted, avoiding local pressure accumulation, reducing the influence of residual axial force on the impeller of the low-pressure section 1001, improving the stability, safety and service life of the multi-stage centrifugal pump in operation, and improving the processing capacity of the system to the high-pressure medium, and enhancing the dynamic adjustment performance of the residual axial force.

[0079] As one of the embodiments, as shown in Figures 10 to 19 The outer periphery of the balance shaft sleeve 7001 is provided with a low-pressure throttling thread 7016, which is arranged at a position corresponding to the position of the low-pressure throttling ring 9001. When the pump shaft 5001 drives the balance shaft sleeve 7001 to rotate synchronously, the low-pressure throttling thread 7016 guides and promotes the movement of the high-pressure medium towards the low-pressure throttling outlet 7017, effectively preventing the backflow of the high-pressure medium, and enhancing the controllability of the flow path of the high-pressure medium.

[0080] As one of the embodiments, as shown in Figures 10 to 19As shown, a high-pressure balancing channel 7004 is defined between the water inlet and outlet sections 3001 and the high-pressure section 2001. One end of the high-pressure balancing channel 7004 communicates with the medium outlet 3002 and the fluid chamber 0001 of the high-pressure section 2001, respectively, and the other end communicates with the high-pressure flow-blocking inlet 7008. The high-pressure balancing channel 7004 is disposed between the high-pressure section 2001 and the water inlet and outlet sections 3001, directing the high-pressure medium within the high-pressure section 2001 toward the high-pressure flow-blocking inlet 7008. This channel guides and diverts the flow of the high-pressure medium within the high-pressure section 2001, with the majority of the high-pressure medium exiting through the medium outlet 3002 and the remaining portion entering the high-pressure flow-blocking inlet 7008 through the high-pressure balancing channel 7004. This allows the high-pressure medium to undergo preliminary pressure distribution adjustment before entering the high-pressure flow-blocking inlet 7008.

[0081] Further, such as Figures 10 to 19 As shown, a low-pressure balancing flow channel 7020 is defined between the water inlet and outlet sections 3001 and the low-pressure section 1001. One end of the low-pressure balancing flow channel 7020 is connected to the transition elbow 4001, and the other end is connected to the low-pressure flow blocking outlet 7017. The medium flows out of the low-pressure flow blocking outlet 7017 and enters the transition elbow 4001 through the low-pressure balancing flow channel 7020, and then flows back to the high-pressure section 2001 through the transition elbow 4001.

[0082] As one embodiment, Figure 17As shown, the water inlet and outlet section 3001 is connected with a high-pressure throttling ring 8001, the balance shaft sleeve 7001 is connected to the pump shaft 5001 and is sleeved on the outer periphery of the pump shaft 5001, the high-pressure throttling ring 8001 is sleeved on the outer periphery of the balance shaft sleeve 7001, the high-pressure throttling ring 8001 and the outer periphery of the balance shaft sleeve 7001 define a flow resistance cavity 7007, the flow resistance cavity 7007 is provided with a high-pressure flow resistance inlet 7008 and a high-pressure flow resistance outlet 7009, the high-pressure flow resistance inlet 7008 and the high-pressure flow resistance outlet 7009 are oppositely arranged at two ends of the flow resistance cavity 7007 along the axial direction of the balance shaft sleeve 7001, the high-pressure throttling ring 8001 is provided with a high-pressure ring end face 8002, the balance shaft sleeve 7001 is provided with a high-pressure shaft end face 7010, and the high-pressure flow resistance inlet 7008 is located between the high-pressure ring end face 8002 and the high-pressure shaft end face 7010. The balance shaft sleeve 7001 is connected to the pump shaft 5001 and is sleeved on the outer periphery of the pump shaft 5001, so as to fix the balance shaft sleeve 7001 and drive the balance shaft sleeve 7001 to rotate synchronously through the pump shaft 5001. The high-pressure throttling ring 8001 is sleeved on the outer periphery of the balance shaft sleeve 7001, the high-pressure throttling ring 8001 and the outer periphery of the balance shaft sleeve 7001 define the flow resistance cavity 7007, the flow resistance cavity 7007 is provided with the high-pressure flow resistance inlet 7008 and the high-pressure flow resistance outlet 7009, the high-pressure flow resistance inlet 7008 and the high-pressure flow resistance outlet 7009 are oppositely arranged at two ends of the flow resistance cavity 7007 along the axial direction of the balance shaft sleeve 7001, the high-pressure flow resistance inlet 7008 of the flow resistance cavity 7007 is used for introducing the high-pressure medium of the high-pressure section 2001; the high-pressure flow resistance inlet 7008 and the high-pressure flow resistance outlet 7009 are in communication, the high-pressure medium flows out of the high-pressure flow resistance outlet 7009 to form a pressure relief channel, so that part of the high-pressure medium between the high-pressure section 2001 and the water inlet and outlet section 3001 can flow out through the pressure relief channel, the generation of residual axial force of the high-pressure section 2001 towards the low-pressure section 1001 is reduced, and the service life and operation reliability of the water pump are improved.

[0083] As one of the embodiments, as Figure 17As shown, the outer circumferential surface of the balance shaft sleeve 7001 is provided with a flow resistance inclined surface 7011 located in the flow resistance cavity 7007, the flow resistance inclined surface 7011 is provided with a first inclined surface end 7012 and a second inclined surface end 7013, the first inclined surface end 7012 is arranged towards the high-pressure flow resistance inlet 7008, and the second inclined surface end 7013 is arranged obliquely towards the axis of the balance shaft sleeve 7001, the high-pressure flow resistance outlet 7009 is located on one side of the second inclined surface end 7013 in the axial direction of the balance shaft sleeve 7001, and the high-pressure flow resistance inlet 7008 and the high-pressure flow resistance outlet 7009 are arranged in a radial direction offset manner along the balance shaft sleeve 7001. The high-pressure medium generates a force opposite to the residual axial force in the flow resistance cavity 7007. The throttling process of the high-pressure medium in the flow resistance cavity 7007 counteracts the residual axial force, thereby improving the operation stability and service life of the pump. The radial direction offset arrangement of the high-pressure flow resistance inlet 7008 and the high-pressure flow resistance outlet 7009 prolongs and optimizes the flow path of the high-pressure medium in the flow resistance cavity 7007. After the high-pressure medium enters the flow resistance cavity 7007 from the high-pressure flow resistance inlet 7008, the high-pressure medium collides with the inner wall of the flow resistance cavity 7007 opposite to the high-pressure flow resistance inlet 7008, and then collides with the flow resistance inclined surface 7011 in the opposite direction along the axial direction. The impact of the high-pressure medium on the flow resistance inclined surface 7011 directly generates a balance force opposite to the direction of the residual axial force; the flow of the medium on the inclined surface forms a stable pressure gradient. The first inclined surface end 7012 is arranged towards the high-pressure flow resistance inlet 7008, and the second inclined surface end 7013 is arranged obliquely towards the axis of the balance shaft sleeve 7001, which not only optimizes the direction of the impact force, but also guides the orderly flow of the high-pressure medium to the high-pressure flow resistance outlet 7009, avoids the accumulation of the high-pressure medium in the flow resistance cavity 7007, and improves the stability and reliability of the axial force balance. As an embodiment, the balance cavity 3007 is in communication with the transition elbow 4001 through the balance hole 3008, and the balance cavity 3007, the flow resistance cavity 7007, the first thrust groove 7002, the balance hole 3008, and the transition elbow 4001 are connected to form a residual axial force balance system.

[0084] As an embodiment, as shown in FIG. 6, the balance cavity 3007 is in communication with the transition elbow 4001 through the balance hole 3008, and the balance cavity 3007, the flow resistance cavity 7007, the first thrust groove 7002, the balance hole 3008, and the transition elbow 4001 are connected to form a residual axial force balance system. Figure 26As shown, the high-pressure section 2001 is located between the water inlet and outlet section 3001 and the first box 6001, the first box 6001 is connected to the high-pressure section 2001, the first box 6001 is provided with a stabilizing groove 6002, the stabilizing groove 6002 is connected with a rotor stabilizing assembly 6008, the rotor stabilizing assembly 6008 includes a first elastic member 6009, a second elastic member 6010 and a first bearing 6011 for sleeving on the pump shaft 5001, the first bearing 6011 is located between the first elastic member 6009 and the second elastic member 6010, one end of the first elastic member 6009 and the second elastic member 6010 respectively abuts against the first bearing 6011, the other end of the first elastic member 6009 and the second elastic member 6010 is connected to the stabilizing groove 6002. The first box 6001 is provided with a stabilizing groove 6002, and the rotor stabilizing assembly 6008 is connected to the stabilizing groove 6002 to realize fixation and form an anti-rotor micro-shift device. The rotor stabilizing assembly 6008 includes a first elastic member 6009, a second elastic member 6010 and a first bearing 6011, the first bearing 6011 is sleeved on the pump shaft 5001, and the first bearing 6011 realizes positioning of the pump shaft 5001 while not affecting rotation of the pump shaft 5001. The first bearing 6011 is located between the first elastic member 6009 and the second elastic member 6010, and the first bearing 6011 is connected in the stabilizing groove 6002 to realize positioning. One end of the first elastic member 6009 away from the first bearing 6011 is connected to the stabilizing groove 6002 to realize fixation of the first elastic member 6009, the other end of the first elastic member 6009 abuts against the first bearing 6011, when the pump shaft 5001 moves towards the first elastic member 6009, the pump shaft 5001 drives the first bearing 6011 to move towards the first elastic member 6009, the first bearing 6011 exerts pressure on the first elastic member 6009, the first elastic member 6009 drives the first bearing 6011 to reset under the action of elastic force, and the first bearing 6011 drives the pump shaft 5001 to reset synchronously. One end of the second elastic member 6010 away from the first bearing 6011 is connected to the stabilizing groove 6002 to realize fixation of the second elastic member 6010, the other end of the second elastic member 6010 abuts against the first bearing 6011, when the pump shaft 5001 moves towards the second elastic member 6010, the pump shaft 5001 drives the first bearing 6011 to move towards the second elastic member 6010, the first bearing 6011 exerts pressure on the second elastic member 6010, the second elastic member 6010 drives the first bearing 6011 to reset under the action of elastic force, and the second bearing drives the pump shaft 5001 to reset synchronously. When the pump shaft 5001 is at the initial position, the first elastic member 6009 and the second elastic member 6010 do not exert axial force on the pump shaft 5001.The pump shaft 5001 will produce a slight axial movement due to the working condition pressure fluctuation, and since the first spring and the second spring provide the first bearing 6011 with the acting force in two directions, the slight axial movement of the pump shaft 5001 due to the working condition pressure fluctuation can be effectively absorbed, the slight axial movement of the pump shaft 5001 is relieved, and the pump shaft 5001 is kept at the initial position.

[0085] As one of the embodiments, as shown in Figure 1 The water inlet section 1007, the first-stage middle section 1015, the low-pressure middle section 1009 and the water inlet and outlet section 3001 are sequentially connected by the sealing rings, the water inlet and outlet section 3001 and one end of the transition elbow 4001 are connected by the sealing ring, the other end of the transition elbow 4001 is connected by the sealing ring, the secondary water inlet section 2006, the high-pressure middle section 2008 and the water inlet and outlet section 3001 are sequentially connected by the sealing rings, the cavity high sealing function of the pump cavity is formed, the high-pressure side medium continuously pushes the sealing ring to the low-pressure side to contact, and the leakage of the high-pressure medium in the pump cavity is effectively prevented.

[0086] In summary, the reliable double-shell self-balancing multi-stage centrifugal pump can install more impellers (up to 30 stages or more) in series, so that the flow rate of the pump reaches 6000 m 3 / h or more, the lift of the pump reaches 5000 m or more, the rotating speed of the pump reaches 1500 r / min-20000 r / min, and the matching power of the pump reaches 40000 Kw or more; the double high anti-cavitation system, the residual axial force balancing system, the anti-rotor slight movement function, the cavity high sealing function, the cavity grading pressure maintaining and heat exchanging function and the cavity grading stabilizing function are arranged, so that the technical defects and problems such as the difficult start of the pump, the deformation of the cavity and other components, the sag of the rotor component and the cavity, the operation cavitation, the slight movement of the rotor component, the large operation vibration caused by the residual axial force, the large operation noise, the leakage in the conveying process, the high production cost, the low assembly precision of the pump, the weak overall rigidity and strength of the pump cavity and the rotor component, the brittle fracture and stress fracture of the part material caused by the temperature, the alternating fatigue fracture of the pump shaft and the like are completely solved, the safe, reliable and stable operation of the multi-stage pump is ensured, the service life of the pump is improved, the production, operation, maintenance and repair costs of the pump are reduced, the production and use life cycle of the pump is improved, the multi-stage pump can be applied to more kinds of complex and variable fields and working conditions, and more economic value and social benefits are generated.

[0087] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and substitutions can be made, and these improvements and substitutions should be considered as the protection scope of the present application.

Claims

1. A reliable double-shell self-balancing multi-stage centrifugal pump, characterized by: The pump comprises a low-pressure section, a high-pressure section, a pump shaft, a pressure relief pipe and a mechanical seal seat. The low-pressure section is connected to the high-pressure section to form a fluid cavity. The mechanical seal seat is connected to the side of the high-pressure section away from the low-pressure section. The pump shaft is respectively provided through the low-pressure section, the high-pressure section and the mechanical seal seat. The low-pressure section is provided with a medium inlet and an inducer chamber. Both ends of the inducer chamber are respectively connected to the medium inlet and the fluid cavity. An inducer connected to the pump shaft is provided in the inducer chamber. The pump shaft sleeve is provided with a throttling ring, which is located at one end of the high-pressure section away from the low-pressure section. The outer periphery of the throttling ring is provided with a drainage thread, and a throttling channel is defined between the drainage thread and the high-pressure section. The mechanical seal seat is provided with a pressure relief channel, one end of the throttling channel is connected to the fluid cavity, and the other end is connected to the pressure relief channel, and the pressure relief channel is connected to the inducer chamber through the pressure relief pipe.

2. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 1 is characterized in that: The pump shaft sleeve is provided with a mechanical seal sleeve, and the mechanical seal sleeve protrudes radially to form a mechanical seal shaft ring. The mechanical seal shaft ring, the mechanical seal seat and the high-pressure section define a pressure relief chamber. One end of the mechanical seal sleeve is connected to the throttling ring, one end of the throttling channel is communicated with the pressure relief chamber, and one end of the pressure relief channel is communicated with the pressure relief chamber.

3. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 2, characterized in that: The high-pressure section includes a high-pressure impeller, a high-pressure middle section and a secondary water inlet section. The low-pressure section, the high-pressure middle section and the secondary water inlet section define the fluid cavity. The high-pressure impeller is connected to the pump shaft and is located in the high-pressure middle section. The secondary water inlet section is connected to the side of the high-pressure middle section away from the low-pressure section. The secondary water inlet section is connected between the high-pressure middle section and the mechanical seal seat. The secondary water inlet section is communicated with the low-pressure section. The throttling ring and the secondary water inlet section define the throttling channel. The throttling channel is provided with a diversion inlet. The diversion inlet is located on the side of the secondary water inlet section facing the high-pressure middle section. The other end of the secondary water inlet section and the mechanical seal seat and the mechanical seal shaft sleeve define the pressure relief cavity.

4. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 1, characterized in that: The inducer chamber is provided with a jet hole, and the side of the inducer facing the low-pressure section is provided with an inducer suction surface. The low-pressure section is provided with a jet channel connected to the pressure relief pipe, one end of the jet hole is connected to the jet channel, and the other end of the jet hole is arranged toward the inducer suction surface.

5. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 4 is characterized in that: The low-pressure section includes a water inlet section and a first-stage middle section, the first-stage middle section is connected to the side of the water inlet section facing the high-pressure section, the medium inlet is arranged in the water inlet section, the inducer chamber is connected to the first-stage middle section, the water inlet section is provided with an induction mounting port on the side facing the first-stage middle section, the inducer chamber is provided with an induction channel extending along the axial direction, the inducer is located in the induction channel, the two ends of the induction channel are respectively connected to the medium inlet and the fluid cavity, and the jet holes are respectively connected to the jet channel and the induction channel.

6. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 5, characterized in that: The low-pressure section also includes a low-pressure middle section, the first-stage middle section is connected between the water inlet section and the low-pressure middle section, the inducer chamber is communicated with the low-pressure middle section at one end away from the water inlet section, the pump shaft is connected with a low-pressure impeller, the low-pressure impeller is located on the side of the low-pressure middle section facing the inducer chamber, the inducer chamber and the first-stage middle section define a degassing chamber, the inducer chamber is provided with a degassing hole, the degassing hole is arranged toward the low-pressure impeller, the degassing chamber is communicated with the inducer chamber through the degassing hole, the water inlet section is provided with a degassing channel for communicating with a degassing device, and the degassing channel is communicated with the degassing chamber.

7. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 1, characterized in that: It also includes a transition elbow, an inlet and outlet water section, a liquid inlet main pipe and a liquid outlet main pipe, the pump shaft is passed through the inlet and outlet water section, the inlet and outlet water section is located between the low-pressure section and the high-pressure section, the low-pressure section is provided with a medium inlet, the inlet and outlet water section is provided with a medium outlet, the low-pressure section is connected to one end of the transition elbow through the inlet and outlet water section, and the other end is connected to an end of the high-pressure section away from the inlet and outlet water section, and the high-pressure section is connected to the inlet and outlet water section to form a fluid cavity; The outer periphery of the low-pressure section is provided with a low-pressure cylinder, and the low-pressure cylinder and the low-pressure section define a low-pressure heat exchange cavity, and the low-pressure heat exchange cavity is provided with a low-pressure heat exchange inlet and a low-pressure heat exchange outlet. The outer periphery of the high-pressure section is provided with a high-pressure cylinder, and the high-pressure cylinder and the high-pressure section define a high-pressure heat exchange cavity, and the high-pressure heat exchange cavity is provided with a high-pressure heat exchange inlet and a high-pressure heat exchange outlet. The low-pressure heat exchange inlet and the high-pressure heat exchange inlet are respectively connected to the liquid inlet main pipe, and the low-pressure heat exchange outlet and the high-pressure heat exchange outlet are respectively connected to the liquid outlet main pipe, and the low-pressure heat exchange inlet, the low-pressure heat exchange outlet, the high-pressure heat exchange inlet and the high-pressure heat exchange outlet are respectively connected to the valve body.

8. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 1, characterized in that: The pump further comprises an inlet and outlet water section assembly and a transition elbow, wherein the inlet and outlet water section assembly is located between the low-pressure section and the high-pressure section, and the pump shaft is coaxially disposed through the low-pressure section, the inlet and outlet water section assembly, and the high-pressure section, respectively. The low-pressure section is connected to one end of the transition elbow through the inlet and outlet water section assembly, and the other end of the transition elbow is connected to an end of the high-pressure section away from the inlet and outlet water section. The water inlet and outlet section assembly is provided with a balancing chamber, a balancing hole, a medium outlet and a high-pressure choke inlet. The medium outlet and the high-pressure choke inlet are respectively connected to the high-pressure section. The high-pressure choke inlet is located between the pump shaft and the medium outlet. The high-pressure choke inlet is connected to the balancing chamber, and the balancing chamber is connected to the transition elbow through the balancing hole.

9. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 8, characterized in that: The inlet and outlet water section assembly includes an inlet and outlet water section, a balancing sleeve and a high-pressure throttling ring. The axial ends of the inlet and outlet water section are respectively connected to the low-pressure section and the high-pressure section. The balancing chamber, the balancing hole and the medium outlet are respectively opened in the inlet and outlet water section. The high-pressure throttling ring is connected to the side of the inlet and outlet water section facing the high-pressure section. The balancing sleeve is sleeved on the outer periphery of the pump shaft. The high-pressure throttling ring is sleeved on one end of the balancing sleeve facing the high-pressure section. A high-pressure flow resistance inlet is defined between one end of the high-pressure throttling ring and the balancing sleeve. The other end of the high-pressure throttling ring is located in the balancing chamber.

10. The reliable double-casing self-balancing multi-stage centrifugal pump according to claim 9, characterized in that: The inlet and outlet water section assembly also includes a low-pressure throttling ring, which is connected to the side of the inlet and outlet water section facing the low-pressure section. The low-pressure throttling ring is sleeved on one end of the balancing sleeve facing the low-pressure section. One end of the low-pressure throttling ring is located in the balancing chamber and defines a medium diffusion port between the low-pressure throttling ring and the high-pressure throttling ring. A low-pressure choke outlet is defined between the other end of the low-pressure throttling ring and the balancing sleeve, and the low-pressure choke outlet is connected to the transition elbow.

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