A multi-stage centrifugal pump with cavitation resistance

Abstract

The utility model relates to the technical fields of pump discloses a multistage centrifugal pump of anti cavitation, including low pressure section, high pressure section, pump shaft, pressure relief pipe and machine seal seat, low pressure section and high pressure section intercommunication form fluid cavity, machine seal seat connects in high pressure section far from low pressure section one side, and pump shaft is arranged in low pressure section, high pressure section and machine seal seat respectively, low pressure section is equipped with medium inlet and inducer room, and inducer room both ends are connected with medium inlet and fluid cavity communication respectively, and inducer room is equipped with inducer connected in pump shaft, and low pressure section is equipped with jet flow channel, and jet flow channel is connected with inducer room, and machine seal seat is equipped with pressure relief channel, and pressure relief channel is connected with fluid cavity in high pressure section far from low pressure section one side, and jet flow channel and pressure relief channel are connected through pressure relief pipe. The utility model discloses a multistage centrifugal pump of anti cavitation, and high pressure medium is introduced at inducer, avoids cavitation, and drives low pressure medium to accelerate flow.

Description

Technical Field

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

[0002] Currently, multistage centrifugal pumps are widely used in industrial and energy sectors. However, in actual operation, they are prone to cavitation due to insufficient suction conditions or changes in operating conditions. This leads to increased vibration and noise, and causes severe cavitation damage to critical components such as the impeller, guide vanes, and intermediate sections, affecting the pump's reliability and service life. Existing self-balancing multistage centrifugal pumps are particularly susceptible to cavitation under conditions such as increased medium temperature, insufficient suction head, and excessively high or low operating flow rates, severely impacting normal operation. To avoid cavitation, additional pre-pressurization equipment or elevated water tanks are typically required. This not only increases system investment and operating costs but also reduces the overall economic efficiency and reliability of operation. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. It provides a cavitation-resistant multistage centrifugal pump that introduces a high-pressure medium at the inducer to prevent cavitation and accelerate the flow of a low-pressure medium.

[0004] To achieve the above objectives, this utility model provides a cavitation-resistant multistage centrifugal pump, including 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 connected 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 passes through the low-pressure section, the high-pressure section, and the mechanical seal seat respectively.

[0005] The low-pressure section is provided with a medium inlet and an inducer chamber. The two ends of the inducer chamber are respectively connected to the medium inlet and the fluid cavity. The inducer chamber is provided with an inducer connected to the pump shaft. The low-pressure section is provided with a jet channel, which is connected to the inducer chamber. The mechanical seal seat is provided with a pressure relief channel, which is connected to the fluid cavity on the side of the high-pressure section away from the low-pressure section. The jet channel and the pressure relief channel are connected through a pressure relief pipe.

[0006] As a preferred embodiment, the low-pressure section includes an inlet section and a first-stage intermediate section. The first-stage intermediate section is connected to the side of the inlet section facing the high-pressure section. The medium inlet is located in the inlet section. The inducer chamber is connected within the first-stage intermediate section. The side of the inlet section facing the first-stage intermediate section has an inducer installation port. The inducer chamber has a jet hole and an axially extending inducer channel. The inducer is located within the inducer channel. The two ends of the inducer channel are respectively connected to the medium inlet and the fluid cavity. The jet hole is connected to both the jet channel and the inducer channel.

[0007] As a preferred embodiment, the inducer wheel is provided with an inducer wheel suction surface on the side facing the water inlet section, and the jet hole is arranged facing the inducer wheel suction surface.

[0008] As a preferred embodiment, the water inlet section is provided with a jet channel, the jet channel is arranged around the induction installation port, the induction wheel chamber is connected to the opening of the jet channel, a plurality of jet holes are provided, the plurality of jet holes are arranged at intervals along the circumference of the induction wheel chamber, the plurality of jet holes are respectively connected to the jet channel, and a plurality of jet channels are provided, the plurality of jet channels are arranged at intervals along the circumference of the water inlet section and are connected to the jet channel.

[0009] As a preferred embodiment, the inducer chamber is provided with a first sealing ring and a second sealing ring on the side facing the jet channel, the jet hole and the jet channel are respectively located between the first sealing ring and the second sealing ring, and the first sealing ring and the second sealing ring are respectively sealed to the inducer chamber and the water inlet section.

[0010] As a preferred embodiment, an included angle c is formed between the axes of the two jet holes arranged radially opposite each other in the inducer chamber, wherein the included angle c = 15°-75°.

[0011] As a preferred embodiment, the jet hole is provided with a jet inlet and a jet outlet, the jet inlet is connected to the jet groove, the jet outlet is disposed towards the inducer wheel, and the diameter of the jet inlet is larger than the diameter of the jet outlet.

[0012] As a preferred embodiment, the jet orifice forms an included angle b between its two opposite ends along the radial direction, the included angle b being 6°-30°.

[0013] As a preferred embodiment, the low-pressure section further includes a low-pressure intermediate section, the first-stage intermediate section is connected between the water inlet section and the low-pressure intermediate section, the end of the inducer chamber away from the water inlet section is connected to the low-pressure intermediate section, the pump shaft is connected to a low-pressure impeller, the low-pressure impeller is located on the side of the low-pressure intermediate section facing the inducer chamber, the inducer chamber and the first-stage intermediate section define a degassing chamber, the inducer chamber is provided with a degassing hole, the degassing hole is arranged facing the low-pressure impeller, the degassing chamber is connected to the inducer chamber through the degassing hole, and the water inlet section is provided with a degassing channel for communicating with a degassing device, the degassing channel is connected to the degassing chamber.

[0014] As a preferred embodiment, the low-pressure impeller has an impeller suction surface on the side facing the inducer chamber, and the degassing hole faces the impeller suction surface.

[0015] Compared with existing technologies, this utility model's anti-cavitation multistage centrifugal pump offers the following advantages: The low-pressure section and high-pressure section are connected to form a fluid cavity, ensuring the flow of media between them. The mechanical seal is connected to the side of the high-pressure section furthest from the low-pressure section, located at the end of the high-pressure section where the medium pressure is higher, facilitating the pressure relief channel to obtain high-pressure media for jet propagation. The pump shaft passes through the low-pressure section, high-pressure section, and mechanical seal. The inducer is connected to the pump shaft, driving the impeller and inducer to rotate, ensuring the normal operation of the entire pump system. The low-pressure section has a medium inlet and an inducer chamber. The medium enters the low-pressure section from the medium inlet for pressurization, and the inducer chamber provides installation space for the inducer. Both ends of the inducer chamber are connected to the medium inlet and the fluid cavity, respectively, ensuring the medium enters the inducer chamber from the medium inlet and then into the subsequent fluid cavity, guaranteeing a smooth medium flow path. The low-pressure section has a jet channel connected to the inducer chamber. This jet channel is the passage for the high-pressure medium to enter the inducer chamber, ensuring that the high-pressure jet can enter the inducer area. The mechanical seal seat is equipped with a pressure relief channel, which connects to the fluid cavity on the side of the high-pressure section furthest from the low-pressure section. This channel is used to draw out a portion of the high-pressure medium from the end of the high-pressure section. The jet channel and the pressure relief channel are connected by a pressure relief pipe, which serves as a transmission channel for the high-pressure medium, introducing it into the jet channel and then into the inducer chamber. The high-pressure medium forms a localized high-pressure zone near the inducer inlet, raising the pressure at the inducer inlet and effectively preventing cavitation. The high-pressure jet mixes with the low-pressure medium within the inducer chamber, accelerating the flow of the low-pressure medium and allowing it to flow more smoothly into the inducer, avoiding cavitation caused by uneven flow velocity or insufficient pressure. Attached Figure Description

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

[0017] Figure 2 This is a schematic diagram of the assembly structure of the water inlet section, the first stage middle section, and the low-pressure middle section in an embodiment of this utility model.

[0018] Figure 3 This is an embodiment of the present utility model. Figure 2 A magnified structural diagram at point 6B.

[0019] Figure 4 This is a cross-sectional structural diagram of the water inlet section according to an embodiment of the present invention.

[0020] Figure 5 This is a front view of the water inlet section of an embodiment of this utility model.

[0021] Figure 6 This is a front view of the induced wheel chamber in an embodiment of this utility model.

[0022] Figure 7This is a cross-sectional structural diagram of the inducer chamber according to an embodiment of the present invention.

[0023] Figure 8 This is an embodiment of the present utility model. Figure 1 An enlarged structural diagram at point 6A.

[0024] In the picture:

[0025] 0001, Fluid cavity;

[0026] 1001, Low-pressure section; 1002, Medium inlet; 1007, Water inlet section; 1009, Low-pressure intermediate section; 1013, Low-pressure impeller; 1014, Jet channel; 1015, First stage intermediate section; 1016, Jet passage; 1017, Induction installation port; 1018, Impeller suction surface; 1019, Degassing passage; 1020, Degassing interface;

[0027] 2001, High-voltage section; 2012, High-voltage impeller;

[0028] 3001. Inlet / outlet water section; 3002. Medium outlet;

[0029] 4001, Transition bend;

[0030] 5001, Pump shaft; 5006, Drain thread; 5007, Drain inlet;

[0031] 1501, Inducer wheel chamber; 1502, Inducer wheel; 1503, Inducer wheel suction surface; 1504, Induction channel; 1505, First sealing ring; 1506, Second sealing ring; 1507, Jet hole; 1508, Jet inlet; 1509, Jet outlet; 1510, Degassing chamber; 1511, Degassing hole;

[0032] 1601, mechanical seal seat; 1602, pressure relief channel; 1603, pressure relief pipe. Detailed Implementation

[0033] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0034] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" used to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0035] In the description of this utility model, it should be understood that the terms "connected," "linked," and "fixed," etc., used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or a welded connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly defined. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0036] like Figures 1 to 8 As shown, a preferred embodiment of the present invention provides a cavitation-resistant multistage centrifugal pump, comprising 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 and the high-pressure section 2001 are connected 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 passes through the low-pressure section 1001, the high-pressure section 2001, and the mechanical seal seat 1601.

[0037] 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 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. The low-pressure section 1001 is provided with a jet channel 1016, which is connected to the inducer chamber 1501. The mechanical seal seat 1601 is provided with a pressure relief channel 1602, which is connected to the fluid cavity 0001 on the side of the high-pressure section 2001 away from the low-pressure section 1001. The jet channel 1016 and the pressure relief channel 1602 are connected through a pressure relief pipe 1603.

[0038] This utility model discloses an anti-cavitation multistage centrifugal pump. The low-pressure section 1001 and the high-pressure section 2001 are connected to form a fluid cavity 0001, ensuring the flow of medium between the high-pressure section 2001 and the low-pressure section 1001. The mechanical seal seat 1601 is connected to the side of the high-pressure section 2001 away from the low-pressure section 1001, located at the end of the high-pressure section 2001. The higher medium pressure in this location facilitates the pressure relief channel 1602 obtaining high-pressure medium for jet propagation. The pump shaft 5001 passes through the low-pressure section 1001, the high-pressure section 2001, and the mechanical seal seat 1601. The inducer wheel 1502 is connected to the pump shaft 5001, driving the impeller and inducer wheel 1502 to rotate, ensuring the normal operation of the entire pump system. The low-pressure section 1001 is provided with a medium inlet 1002 and an inducer wheel chamber 1501. The medium enters the low-pressure section 1001 from the medium inlet 1002 for pressurization, and the inducer wheel chamber 1501 provides installation space for the inducer wheel 1502. The inducer chamber 1501 is connected at both ends to the medium inlet 1002 and the fluid cavity 0001, respectively, ensuring that the medium enters the inducer chamber 1501 from the medium inlet 1002 and then enters the subsequent fluid cavity 0001, thus ensuring a smooth flow path for the medium. The low-pressure section 1001 is provided with a jet channel 1016, which is connected to the inducer chamber 1501. The jet channel 1016 serves as the channel for the high-pressure medium to enter the inducer chamber 1501, ensuring that the high-pressure jet can enter the inducer 1502 area. The mechanical seal seat 1601 is provided with a pressure relief channel 1602, which is connected to the fluid cavity 0001 on the side of the high-pressure section 2001 away from the low-pressure section 1001. The pressure relief channel 1602 is used to draw out a portion of the high-pressure medium from the end of the high-pressure section 2001. The jet channel 1016 and the pressure relief channel 1602 are connected by a pressure relief pipe 1603. The pressure relief pipe 1603 serves as a transmission channel for the high-pressure medium, introducing the high-pressure medium from the high-pressure section 2001 into the jet channel 1016 and then into the inducer chamber 1501. A local high-pressure zone is formed near the inlet of the inducer 1502, increasing the pressure at the inlet of the inducer 1502 and effectively preventing cavitation. The high-pressure jet mixes with the low-pressure medium within the inducer chamber 1501, accelerating the flow of the low-pressure medium and allowing it to flow more smoothly into the inducer 1502, avoiding cavitation caused by uneven flow velocity or insufficient pressure.

[0039] As one embodiment, such as Figure 1 As shown, the pump shaft 5001 is connected to a low-pressure impeller 1013 located in the low-pressure section 1001 and a high-pressure impeller 2012 located in the high-pressure section 2001. The pump shaft 5001 drives the low-pressure impeller 1013 and the high-pressure impeller 2012 to rotate, thereby achieving a multi-stage pressurization function. The structure of the low-pressure impeller 1013 and the high-pressure impeller 2012 is existing technology and will not be described in detail here.

[0040] Furthermore, such as Figures 2 to 4As shown, the low-pressure section 1001 includes an inlet section 1007 and a first-stage intermediate section 1015. The first-stage intermediate section 1015 is connected to the side of the inlet section 1007 facing the high-pressure section 2001. A medium inlet 1002 is located in the inlet section 1007. An inducer wheel chamber 1501 is connected to the first-stage intermediate section 1015. An inducer installation port 1017 is provided on the side of the inlet section 1007 facing the first-stage intermediate section 1015. The inducer wheel chamber 1501 has a jet hole 1507 and an axially extending inducer channel 1504. The inducer wheel 1502 is located in the inducer channel 1504. The two ends of the inducer channel 1504 are respectively connected to the medium inlet 1002 and the fluid cavity 0001. The jet hole 1507 is connected to the jet channel 1016 and the inducer channel 1504 respectively. The medium inlet 1002 is located in the inlet section 1007, and the medium enters the inducer wheel chamber 1501 from the inlet section 1007. The first-stage intermediate section 1015 is fixedly connected to the inlet section 1007. The inlet section 1007 is provided with an induction installation port 1017. One end of the induction wheel chamber 1501 is connected to the induction installation port 1017, and the other end is connected to the first-stage intermediate section 1015 to fix the induction wheel chamber 1501. Simultaneously, the induction wheel chamber 1501 communicates with the medium inlet 1002 of the inlet section 1007 through the induction installation port 1017. The induction wheel chamber 1501 is provided with a jet hole 1507 and an axially extending induction channel 1504. The jet hole 1507 is used for high-pressure jet medium injection, and the induction channel 1504 serves as the main flow path for the medium from the medium inlet 1002 to the fluid cavity 0001, extending axially to facilitate smooth medium flow. The induction wheel 1502 is located within the induction channel 1504, coinciding with the jet action area to enhance the synergistic effect. The jet hole 1507, jet channel 1016 and induction channel 1504 are connected to ensure that the high-pressure medium can be injected into the induction wheel 1502 in the induction channel 1504 to achieve active pressurization and anti-cavitation effect.

[0041] Furthermore, such as Figure 3 As shown, the inducer wheel 1502 has an inducer wheel suction surface 1503 on the side facing the inlet section 1007, and the jet hole 1507 is set facing the inducer wheel suction surface 1503. This allows the high-pressure medium to pass through the pressure relief channel 1602, pressure relief pipe 1603, and jet channel 1016, and then directly act on the suction surface of the inducer wheel 1502 in the form of a high-speed jet through the jet hole 1507, increasing the pressure level in this area and reducing the required net positive suction head (NPSH) of the pump. At the same time, when the jet is sprayed onto the suction surface, it accelerates the flow of the low-pressure medium in the inlet section 1007, effectively preventing cavitation caused by uneven flow velocity or insufficient pressure, improving the suction performance during the pump start-up phase, and enhancing the operational reliability and service life of the multistage centrifugal pump.

[0042] Furthermore, such as Figure 3As shown, the inlet section 1007 is provided with a jet channel 1014, which surrounds the induction mounting port 1017. The induction wheel chamber 1501 is connected to the opening of the jet channel 1014. Multiple jet holes 1507 are provided, spaced apart circumferentially along the induction wheel chamber 1501, and each jet hole 1507 communicates with the jet channel 1014. Multiple jet channels 1016 are provided, spaced apart circumferentially along the inlet section 1007 and communicating with the jet channel 1014. The annular structure of the jet channel 1014 surrounding the induction mounting port 1017 provides a unified high-pressure medium distribution channel for the multiple jet holes 1507. The inducer chamber 1501 is connected to the open side of the jet channel 1014, forming a sealed connection between the inducer chamber 1501 and the jet channel 1014, thus creating a sealed annular channel. High-pressure media from multiple jet channels 1016 enter the annular jet channel 1014 and then enter the inducer chamber 1501 through multiple jet holes 1507, ensuring that the high-pressure media can only enter the inducer channel 1504 through the jet holes 1507, improving system sealing and efficiency. Multiple jet holes 1507 are spaced circumferentially along the inducer chamber 1501 to achieve more uniform jet coverage and enhance the pressure boosting effect near the inducer suction surface 1503. Multiple jet channels 1016 are connected to vent pipes, introducing high-pressure media from the pressure relief pipe 1603 into the jet channel 1014, forming a multi-point power supply path and improving flow stability and response speed.

[0043] In one embodiment, the end of the pressure relief pipe 1603 facing the water inlet section 1007 is connected to multiple pressure relief branch pipes, and each pressure relief branch pipe is connected to a jet channel 1016 to achieve the diversion of multiple jet channels 1016.

[0044] Furthermore, such as Figure 3 and Figure 7 As shown, the inducer chamber 1501 facing the jet channel 1014 is provided with a first sealing ring 1505 and a second sealing ring 1506. The jet hole 1507 and the jet channel 1014 are respectively located between the first sealing ring 1505 and the second sealing ring 1506. The first sealing ring 1505 and the second sealing ring 1506 are respectively sealed to the inducer chamber 1501 and the water inlet section 1007. The axially distributed first sealing ring 1505 and second sealing ring 1506 achieve multiple sealing protection for the jet channel 1014 and the jet hole 1507 area, preventing leakage of the high-pressure jet medium during transmission and improving sealing reliability. At the same time, confining the jet channel 1014 between the two sealing rings avoids the diffusion or backflow of the high-pressure medium in non-target areas, ensuring jet efficiency.

[0045] As one embodiment, such as Figure 3 and Figure 7As shown, the inducer chamber 1501 has a first sealing groove and a second sealing groove on the side facing the jet channel 1014. A first sealing ring 1505 is connected to the first sealing groove, and a second sealing ring 1506 is connected to the second sealing groove. The first and second sealing grooves on the side of the inducer chamber 1501 facing the jet channel 1014 are used to install the first sealing ring 1505 and the second sealing ring 1506, respectively. The sealing grooves precisely position the sealing rings, preventing misalignment or detachment during assembly or operation, significantly improving the assembly accuracy and operational stability of the sealing structure.

[0046] Furthermore, the axes of the two jet holes 1507 arranged radially opposite to each other in the inducer chamber 1501 form an included angle c, which is 15°-75°, to avoid mutual interference between the jets of the jet holes 1507 arranged radially opposite to each other and to ensure the pressurization effect.

[0047] Furthermore, such as Figure 3 As shown, the jet orifice 1507 has a jet inlet 1508 and a jet outlet 1509. The jet inlet 1508 is connected to the jet channel 1014, and the jet outlet 1509 is oriented towards the inducer wheel 1502. The diameter of the jet inlet 1508 is larger than the diameter of the jet outlet 1509. While maintaining a constant flow rate, this allows the high-pressure medium to obtain a higher flow velocity and stronger kinetic energy when passing through the jet orifice 1507. The high-speed jet directly acts on the suction surface 1503 region of the inducer wheel, effectively increasing the pressure level in that region.

[0048] Furthermore, such as Figure 7 As shown, an included angle b is formed between the two opposite ends of the jet orifice 1507 along the radial direction, with included angle b = 6°-30°. By using an appropriate angle range of included angle b, the flow velocity and energy concentration of the high-pressure medium within the jet orifice 1507 are improved, while the coverage effect and impact strength of the jet on the inducer wheel suction surface 1503 are also improved.

[0049] As one embodiment, such as Figure 6 and Figure 7 As shown, the number of jet holes 1507 is greater than or equal to three. By setting multiple jet holes 1507, the high-pressure medium can act on the region of the inducer suction surface 1503 from multiple directions simultaneously, which significantly improves the pressure level and energy distribution uniformity in this region.

[0050] Furthermore, such as Figure 2As shown, the low-pressure section 1001 also includes a low-pressure intermediate section 1009. The first-stage intermediate section 1015 is connected between the water inlet section 1007 and the low-pressure intermediate section 1009. The end of the inducer chamber 1501 away from the water inlet section 1007 is connected to the low-pressure intermediate section 1009. The pump shaft 5001 is connected to a low-pressure impeller 1013. The low-pressure impeller 1013 is located on the side of the low-pressure intermediate section 1009 facing the inducer chamber 1501. The inducer chamber 1501 and the first-stage intermediate section 1015 define a degassing chamber 1510. The inducer chamber 1501 is provided with a degassing hole 1511. The degassing hole 1511 is set facing the low-pressure impeller 1013. The degassing chamber 1510 is connected to the inducer chamber 1501 through the degassing hole 1511. The water inlet section 1007 is provided with a degassing channel 1019 for communicating with the degassing device. The degassing channel 1019 is connected to the degassing chamber 1510. A low-pressure intermediate section 1009 is added to the low-pressure section 1001, and a degassing chamber 1510 is formed between the first-stage intermediate section 1015 and the inducer chamber 1501. A degassing hole 1511 is provided on the inducer chamber 1501, connecting the degassing chamber 1510 to the inducer chamber 1501. The end of the inducer chamber 1501 away from the inlet section 1007 is connected to the low-pressure intermediate section 1009, and thus to the fluid chamber 0001. The degassing hole 1511 is arranged towards the low-pressure impeller 1013, allowing the released gas to enter the degassing chamber 1510 through the degassing hole 1511 and be discharged to the external degassing device via the degassing channel 1019 on the inlet section 1007. The operation of the external degassing device actively removes gas from the inlet area of ​​the low-pressure impeller 1013, effectively preventing cavitation caused by gas accumulation.

[0051] As one embodiment, such as Figures 2 to 5 As shown, the degassing channel 1019, jet channel 1016, and medium inlet 1002 are isolated from each other in the water inlet section 1007. The water inlet section 1007 is equipped with the degassing channel 1019, jet channel 1016, and medium inlet 1002, respectively, and these three are isolated from each other. This ensures that the functional channels do not interfere with each other during operation, avoids crossflow or pressure interference between the high-pressure jet medium, the degassed gas, and the main medium, and improves the functional independence and operational stability of the system. By rationally integrating the degassing channel 1019, jet channel 1016, and medium inlet 1002 into the same water inlet section 1007, a compact layout is achieved.

[0052] In one embodiment, the water inlet section 1007 is provided with an inner water inlet cavity and a degassing outer cavity. The inner water inlet cavity is connected to the medium inlet 1002 and the induction channel 1504 respectively. The degassing outer cavity is arranged around the inner water inlet cavity. A degassing interface 1020 is provided on the side of the degassing outer cavity away from the first stage middle section 1015. The degassing interface 1020 is connected to the degassing device. The end of the degassing outer cavity facing the first stage middle section 1015 is connected to the degassing cavity 1510 to form a degassing channel 1019.

[0053] As one embodiment, the external degassing device is existing technology and will not be described in detail here.

[0054] Furthermore, the low-pressure impeller 1013 has an impeller suction surface 1018 on the side facing the inducer chamber 1501, and a degassing hole 1511 faces the impeller suction surface 1018. By directly aligning the degassing hole 1511 with the impeller suction surface 1018, the gas is guided out as soon as it accumulates or enters, preventing cavitation and ensuring the reliable and efficient operation of the pump.

[0055] As one embodiment, such as Figure 1 As shown, the cavitation-resistant multistage centrifugal pump also includes an inlet / outlet section 3001 and a transition bend 4001. The pump shaft 5001 is coaxially mounted in the low-pressure section 1001, the inlet / outlet section 3001, and the high-pressure section 2001. The inlet / outlet section 3001 is located between the low-pressure section 1001 and the high-pressure section 2001. The low-pressure section 1001 has a medium inlet 1002, and the inlet / outlet section 3001 has a medium outlet 3002. The low-pressure section 1001 is connected to one end of the transition bend 4001 via the inlet / outlet section 3001, and the other end of the transition bend 4001... The high-pressure section 2001 is connected to the end away from the inlet / outlet section 3001. The high-pressure section 2001 is connected to the medium outlet 3002. The low-pressure section 1001, the high-pressure section 2001, and the inlet / outlet section 3001 are coaxially connected to the pump shaft 5001. The water that needs to be pressurized enters from the medium inlet 1002 of the low-pressure section 1001 and is pressurized in the fluid chamber 0001 of the low-pressure section 1001 and the fluid chamber 0001 of the high-pressure section 2001 in sequence to form a high-pressure medium. The high-pressure medium flows out from the medium outlet 3002 of the inlet / outlet section 3001.

[0056] As one embodiment, when the anti-cavitation multistage centrifugal pump is connected only by the low-pressure section 1001 and the high-pressure section 2001 to form a fluid cavity 0001, the medium inlet 1002 is located in the low-pressure section 1001 and the medium outlet 3002 is located in the high-pressure section 2001.

[0057] As one embodiment, such as Figure 8 As shown, the outer circumferential surface of the pump shaft 5001 is provided with a flow-guiding thread 5006. The flow-guiding thread 5006 is located at the end of the high-pressure section 2001 away from the low-pressure section 1001. The end of the flow-guiding thread 5006 facing the low-pressure section 1001 defines a flow-guiding inlet 5007 between it and the high-pressure section 2001. The flow-guiding inlet 5007 communicates with the fluid cavity 0001 of the high-pressure section 2001. The other end of the flow-guiding thread 5006 communicates with the pressure relief channel 1602. By rotating the pump shaft 5001, the flow-guiding thread 5006 is driven to work, and the high-pressure medium flows between the flow-guiding thread 5006 and the high-pressure section 2001 towards the pressure relief channel 1602, realizing the active delivery of the high-pressure medium from the high-pressure section 2001 to the pressure relief channel 1602 without the need for an external pump or power unit, thus saving energy.

[0058] In summary, this utility model embodiment provides a cavitation-resistant multistage centrifugal pump. The low-pressure section 1001 and the high-pressure section 2001 are connected to form a fluid cavity 0001, ensuring the flow of medium between the high-pressure section 2001 and the low-pressure section 1001. The mechanical seal seat 1601 is connected to the side of the high-pressure section 2001 away from the low-pressure section 1001, located at the end of the high-pressure section 2001, where the medium pressure is relatively high, which is beneficial for the pressure relief channel 1602 to obtain high-pressure medium for jetting. The pump shaft 5001 passes through the low-pressure section 1001, the high-pressure section 2001, and the mechanical seal seat 1601. The inducer 1502 is connected to the pump shaft 5001, driving the impeller and the inducer 1502 to rotate, enabling the entire pump system to operate normally. The low-pressure section 1001 is equipped with a medium inlet 1002 and an inducer chamber 1501. The medium enters the low-pressure section 1001 through the medium inlet 1002 and is pressurized. The inducer chamber 1501 provides installation space for the inducer 1502. Both ends of the inducer chamber 1501 are connected to the medium inlet 1002 and the fluid cavity 0001, respectively, ensuring that the medium enters the inducer chamber 1501 from the medium inlet 1002 and then enters the subsequent fluid cavity 0001, guaranteeing a smooth flow path. The low-pressure section 1001 is equipped with a jet channel 1016, which is connected to the inducer chamber 1501. The jet channel 1016 is the passage for the high-pressure medium to enter the inducer chamber 1501, ensuring that the high-pressure jet can enter the inducer 1502 area. The mechanical seal base 1601 is provided with a pressure relief channel 1602, which is connected to the fluid cavity 0001 on the side of the high-pressure section 2001 away from the low-pressure section 1001. The pressure relief channel 1602 is used to draw out a portion of the high-pressure medium from the end of the high-pressure section 2001. The jet channel 1016 is connected to the pressure relief channel 1602 through a pressure relief pipe 1603. The pressure relief pipe 1603 serves as a transmission channel for the high-pressure medium, introducing the high-pressure medium from the high-pressure section 2001 into the jet channel 1016 and then into the inducer chamber 1501. The high-pressure medium forms a local high-pressure zone near the inlet of the inducer 1502, raising the pressure at the inlet of the inducer 1502 and effectively preventing cavitation. The high-pressure jet mixes with the low-pressure medium in the inducer chamber 1501, accelerating the flow of the low-pressure medium and allowing it to flow more smoothly into the inducer 1502, avoiding cavitation caused by uneven flow velocity or insufficient pressure.

[0059] The above are merely preferred embodiments of this utility model. It should be noted that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this utility model, and these improvements and substitutions should also be considered within the protection scope of this utility model.

Claims

1. A cavitation-resistant multistage centrifugal pump, characterized in that: It includes 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 connected 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 passes through the low-pressure section, the high-pressure section, and the mechanical seal seat respectively. The low-pressure section is provided with a medium inlet and an inducer chamber. The two ends of the inducer chamber are respectively connected to the medium inlet and the fluid cavity. The inducer chamber is provided with an inducer connected to the pump shaft. The low-pressure section is provided with a jet channel, which is connected to the inducer chamber. The mechanical seal seat is provided with a pressure relief channel, which is connected to the fluid cavity on the side of the high-pressure section away from the low-pressure section. The jet channel and the pressure relief channel are connected through a pressure relief pipe.

2. The cavitation-resistant multistage centrifugal pump according to claim 1, characterized in that: The low-pressure section includes an inlet section and a first-stage intermediate section. The first-stage intermediate section is connected to the side of the inlet section facing the high-pressure section. The medium inlet is located in the inlet section. The inducer chamber is connected inside the first-stage intermediate section. The side of the inlet section facing the first-stage intermediate section has an inducer installation port. The inducer chamber has a jet hole and an axially extending inducer channel. The inducer is located inside the inducer channel. The two ends of the inducer channel are respectively connected to the medium inlet and the fluid cavity. The jet hole is connected to both the jet channel and the inducer channel.

3. The cavitation-resistant multistage centrifugal pump according to claim 2, characterized in that: The inducer wheel has an inducer wheel suction surface on the side facing the water inlet section, and the jet hole is arranged facing the inducer wheel suction surface.

4. The cavitation-resistant multistage centrifugal pump according to claim 2, characterized in that: The water inlet section is provided with a jet channel, which surrounds the induction installation port. The induction wheel chamber is connected to the opening of the jet channel. Multiple jet holes are provided, which are spaced apart circumferentially along the induction wheel chamber. The multiple jet holes are respectively connected to the jet channel. Multiple jet channels are provided, which are spaced apart circumferentially along the water inlet section and connected to the jet channel.

5. The cavitation-resistant multistage centrifugal pump according to claim 4, characterized in that: The inducer chamber is provided with a first sealing ring and a second sealing ring on the side facing the jet channel. The jet hole and the jet channel are respectively located between the first sealing ring and the second sealing ring. The first sealing ring and the second sealing ring are respectively sealed to the inducer chamber and the water inlet section.

6. The cavitation-resistant multistage centrifugal pump according to claim 4, characterized in that: An included angle c is formed between the axes of the two jet holes arranged radially opposite each other in the inducer chamber, the included angle c = 15°-75°.

7. The cavitation-resistant multistage centrifugal pump according to claim 6, characterized in that: The jet orifice has a jet inlet and a jet outlet. The jet inlet is connected to the jet groove, and the jet outlet is oriented toward the inducer wheel. The diameter of the jet inlet is larger than the diameter of the jet outlet.

8. The cavitation-resistant multistage centrifugal pump according to claim 2, characterized in that: An included angle b is formed between the two opposite ends of the jet orifice in the radial direction, wherein the included angle b = 6°-30°.

9. The cavitation-resistant multistage centrifugal pump according to claim 2, characterized in that: The low-pressure section further includes a low-pressure intermediate section. The first-stage intermediate section is connected between the water inlet section and the low-pressure intermediate section. The end of the inducer chamber away from the water inlet section is connected to the low-pressure intermediate section. The pump shaft is connected to a low-pressure impeller. The low-pressure impeller is located on the side of the low-pressure intermediate section facing the inducer chamber. The inducer chamber and the first-stage intermediate section define a degassing chamber. The inducer chamber is provided with a degassing hole, which is positioned facing the low-pressure impeller. The degassing chamber is connected to the inducer chamber through the degassing hole. The water inlet section is provided with a degassing channel for communication with a degassing device. The degassing channel is connected to the degassing chamber.

10. The cavitation-resistant multistage centrifugal pump according to claim 9, characterized in that: The low-pressure impeller has an impeller suction surface on the side facing the inducer chamber, and the degassing hole faces the impeller suction surface.

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