Energy-saving vertical self-suction two-stage centrifugal pump for ship

Abstract

The application discloses an energy-saving vertical self-suction two-stage centrifugal pump for a ship, which comprises a pump body, a motor arranged above the pump body, a pump shaft in transmission connection with the motor and vertically extending into the pump body, and a suction inlet and a discharge outlet arranged on the pump body; a first-stage impeller and a second-stage impeller are arranged on the pump shaft in an axial direction, the outlet side of the first-stage impeller is communicated with the inlet side of the second-stage impeller through a flow guide channel, and the medium entering the pump through the suction inlet is pressurized by the first-stage impeller and the second-stage impeller in sequence and then discharged through the discharge outlet; a self-suction liquid storage cavity and a gas-liquid separation cavity are arranged in the pump body, the gas-liquid separation cavity is communicated with the outlet side of the first-stage impeller, the self-suction liquid storage cavity is communicated with the inlet side of the first-stage impeller through a backflow channel, and the gas phase region of the gas-liquid separation cavity is communicated with a gas outlet; the probability of suction loss and sudden increase of exhaust resistance of the centrifugal pump under complex marine conditions of the ship is reduced, and the continuity of the self-suction cycle and the stable liquid supply are ensured.

Description

Technical Field

[0001] This invention relates to a self-priming two-stage centrifugal pump, and more particularly to an energy-saving vertical self-priming two-stage centrifugal pump for use in ships. Background Technology

[0002] In the field of marine engineering, self-priming centrifugal pumps are widely used in critical operations such as bilge water discharge, ballast water transfer, and fire protection systems because they do not require a foot valve and can automatically expel air from the suction line and complete priming. However, as ships become larger and more complex, coupled with the inevitable rolling and tilting of the hull during navigation, the design limitations of traditional self-priming pumps are becoming increasingly apparent.

[0003] Existing single-stage or multi-stage self-priming pumps typically rely on a single open reservoir to maintain the required circulating water volume for startup, and use a single vent fixed at a specific position on the top of the reservoir to discharge the gas after gas-liquid separation. This structure can operate stably under ideal horizontal conditions, but when a ship encounters waves and experiences pitching or listing, the pump's attitude changes accordingly. At this time, the fixed vent, originally located at a high position, is easily completely submerged due to the relative displacement of the liquid level within the reservoir, creating a so-called liquid seal. Once the vent is liquid-sealed, the gas separated inside the reservoir cannot escape smoothly, leading to pressure imbalance within the pump, ineffective separation of the gas-liquid mixture, ultimately causing interruption of the self-priming cycle, priming failure, or even prolonged dry-running of the pump, seriously threatening the pump's reliability and the safety of ship operation.

[0004] Furthermore, the traditional design features a large single open liquid storage chamber with a lack of optimized guidance for liquid reflux and gas accumulation paths. This necessitates the filling of a large amount of liquid before each start-up, increasing wasted power consumption and prolonging self-priming time. Simultaneously, due to the fixed and singular exhaust point, stagnant gas masses easily form in the upper part of the chamber under non-horizontal conditions, further compressing the effective liquid circulation space and reducing gas-liquid separation efficiency. This inherent defect, highly sensitive to installation posture, has become a key technical bottleneck restricting the application of traditional self-priming pumps in dynamic marine environments. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides an energy-saving vertical self-priming two-stage centrifugal pump for ships.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: an energy-saving vertical self-priming two-stage centrifugal pump for ships, comprising: a pump body, a motor disposed above the pump body, a pump shaft connected to the motor and extending vertically into the pump body, and an inlet and an outlet disposed on the pump body.

[0007] The pump shaft is axially spaced with a first-stage impeller and a second-stage impeller. The outlet side of the first-stage impeller is connected to the inlet side of the second-stage impeller through a flow guide channel, so that the medium entering from the suction port is pressurized by the first-stage impeller and the second-stage impeller in sequence and then discharged from the discharge port.

[0008] The pump body is equipped with a self-priming liquid storage chamber and a gas-liquid separation chamber. The gas-liquid separation chamber is connected to the outlet side of the first-stage impeller, and the self-priming liquid storage chamber is connected to the inlet side of the first-stage impeller through a return channel. The gas phase region of the gas-liquid separation chamber is connected to the exhaust port.

[0009] The first-stage impeller drives the liquid in the self-priming storage chamber to form a gas-liquid mixture with the intake gas. After the gas-liquid mixture enters the gas-liquid separation chamber, the separated liquid returns to the first-stage impeller through the return channel, and the separated gas is discharged through the exhaust port. After the intake pipeline is filled with liquid, the first-stage impeller and the second-stage impeller are driven by the same motor through the pump shaft and continuously pressurized through the guide channel to complete self-priming and two-stage conveying without setting up an independent air pumping power source.

[0010] In a preferred embodiment of the present invention, the motor is fixedly mounted on the bracket, and the bracket is fixedly connected to the top of the pump cover; the pump shaft passes through the bracket and the pump cover in sequence, and the first-stage impeller and the second-stage impeller are both coaxially fixed on the pump shaft so as to be synchronously driven by the motor.

[0011] In a preferred embodiment of the present invention, a bearing seat is provided between the bracket and the pump cover, the bearing seat is sleeved on the outside of the pump shaft and is used to support the pump shaft; a mechanical seal is provided between the bearing seat and the pump cover, the mechanical seal is arranged around the pump shaft to seal the position where the pump shaft passes through the pump cover.

[0012] In a preferred embodiment of the present invention, the first-stage impeller is located on the side of the second-stage impeller near the pump cover, and a flow guide channel is provided between the first-stage impeller and the second-stage impeller, connecting the outlet side of the first-stage impeller and the inlet side of the second-stage impeller along the axial direction of the pump shaft.

[0013] In a preferred embodiment of the present invention, the flow guiding channel includes an inlet section connected to the outlet side of the first-stage impeller, a transition flow guiding section for changing the fluid flow direction, and an outlet section connected to the inlet side of the second-stage impeller; the transition flow guiding section extends along the outer periphery of the pump shaft to smoothly guide the rotating fluid output from the first-stage impeller to the inlet side of the second-stage impeller.

[0014] In a preferred embodiment of the present invention, both the self-priming liquid storage chamber and the gas-liquid separation chamber are formed in the pump body and located on the outer periphery of the first-stage impeller and the second-stage impeller. The gas-liquid separation chamber is located above the self-priming liquid storage chamber and communicates with it, so that the lower part of the gas-liquid separation chamber forms a liquid collection area and the upper part forms a gas collection area.

[0015] In a preferred embodiment of the present invention, the return channel is a single return channel disposed in the pump body. One end of the return channel is connected to the liquid collection area of ​​the self-priming liquid storage chamber and / or the gas-liquid separation chamber, and the other end is connected to the inlet side of the first-stage impeller, so as to replenish the circulating liquid to the first-stage impeller during the start-up self-priming stage.

[0016] In a preferred embodiment of the present invention, the exhaust port is a single exhaust port located at the top of the gas-liquid separation chamber. The inner end of the exhaust port is connected to the gas collection area, and the outer end is connected to the outside of the pump body. The exhaust port is higher than the connection position between the return channel and the self-priming liquid storage chamber or the gas-liquid separation chamber.

[0017] In a preferred embodiment of the present invention, the suction port and the discharge port are respectively located on opposite sides of the pump body. The suction port is connected to the inlet side of the first-stage impeller through the suction flow channel in the pump body, and the discharge port is connected to the outlet side of the second-stage impeller, so that the main conveying medium flows sequentially along the suction port, the first-stage impeller, the guide channel, the second-stage impeller and the discharge port.

[0018] In a preferred embodiment of the present invention, a fan cover is provided on the upper part of the motor and a junction box is provided on the side; the upper end of the pump body is fixedly connected to the pump cover and the lower end is fixedly connected to the base, and the motor, bracket, pump cover, pump body and base are arranged vertically in sequence.

[0019] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0020] (1) This invention provides an energy-saving vertical self-priming two-stage centrifugal pump for ships. By setting an anti-rolling compartment structure consisting of multiple circumferentially spaced partitions in the self-priming liquid storage chamber, and opening balance holes at the bottom of the partitions, and setting exhaust holes with multiple circumferentially distributed gas inlets at the top of the gas-liquid separation chamber, when the ship rolls, pitches, or tilts continuously, causing the pump body attitude to change, the circumferentially distributed partitions can effectively prevent the stored liquid from migrating and violently swaying to the lower side of the pump body under the action of gravity and inertia. The balance holes maintain the low-level liquid phase balance of each storage unit while limiting the rapid flow of liquid. The multiple circumferentially distributed gas inlets ensure that there is always a gas inlet at a momentary high position connected to the gas phase region, avoiding the loss of effective circulating fluid due to the overall displacement of the liquid storage away from the return port, and eliminating the situation where a single exhaust port is submerged by liquid and forms a liquid seal when the pump body is tilted. Compared with traditional self-priming pumps that use a single open liquid storage chamber and a single exhaust port in a fixed position, this significantly improves the uniformity of liquid distribution and the unobstructedness of the exhaust path under dynamic tilting and swaying conditions, reduces the probability of centrifugal pumps losing suction and experiencing a sudden increase in exhaust resistance under complex marine sea conditions, and ensures the continuity and stable liquid supply of the self-priming cycle.

[0021] (2) This invention provides an energy-saving vertical self-priming two-stage centrifugal pump for ships. By setting an interstage supply liquid area on the liquid phase side of the lower part of the gas-liquid separation chamber between the first-stage impeller and the second-stage impeller, the upper part of the supply liquid area is separated from the gas phase area by a solid baffle. A return discharge channel connecting the upper part of the gas-liquid separation chamber is set at the upper part of the inlet of the second-stage impeller. Under the condition of intermittent air intake at low liquid level, the gas-liquid mixture output by the first-stage impeller completes preliminary separation in the gas-liquid separation chamber. The separated liquid that settles at the bottom enters the supply liquid area to form a natural liquid seal and short-term buffer volume, blocking the large volume gas mass that accumulates at the top from directly entering the second-stage impeller. At the same time, the stored liquid in the supply liquid area smooths out the pressure of the preceding stage. The transient fluctuations in output flow rate, while the trace residual gas entering the vicinity of the second-stage impeller with the liquid is returned to the upper part of the gas-liquid separation chamber and discharged again under the action of buoyancy and pressure difference through the return channel, realizes the independent spatial separation of the liquid intake path of the second-stage impeller and the natural migration path of the gas. Compared with the traditional two-stage pump where the front and rear stages are directly connected in series and the rear impeller has to directly bear the impact of the high gas content medium, it prevents the gas binding phenomenon caused by the large volume of gas entering the second-stage impeller, weakens the transmission of the flow fluctuation of the front stage to the rear stage, avoids the sudden drop and rise of the outlet pressure during the recovery of liquid delivery, and improves the stability of the pump set in the delivery process under the conditions of high gas content of the intake medium and intermittent gas entrainment.

[0022] (3) This invention provides an energy-saving vertical self-priming two-stage centrifugal pump for ships. By installing an anti-swirling component that extends axially and has multiple liquid passage holes on its outer periphery between the suction inlet and the pump body suction channel, and setting a flow stabilizing structure with a flow guide baffle in the gas-liquid separation chamber, during low-level suction, the anti-swirling component occupies the central area of ​​the suction inlet and disperses the suction liquid flow, weakening the concentrated low-pressure state at the center of the suction inlet and the tendency to form suction vortices on the free liquid surface; the flow guide baffle in the flow stabilizing structure circumferentially divides and redirects the rotating gas-liquid flow discharged from the first-stage impeller. By weakening the large-scale circulating motion within the gas-liquid separation chamber, this structure reduces the degree to which external gas is concentrated and drawn into the pump body in the form of gas nuclei vortices from the source. It also creates a stable flow field environment for the upward escape of bubbles within the gas-liquid separation chamber. Compared with traditional self-priming centrifugal pumps that lack inlet suction vortex control and in-chamber rotating flow intervention, it significantly reduces the initial gas content of the suction medium, improves the gas-liquid separation efficiency and liquid flow stability of the gas-liquid separation chamber, improves the inlet hydraulic conditions of each stage impeller, and further consolidates the high-efficiency and stable operation performance of the vertical two-stage centrifugal pump under complex working conditions. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a perspective structural diagram of a preferred embodiment of the present invention;

[0025] Figure 2 This is an overall cross-sectional view of a preferred embodiment of the present invention;

[0026] Figure 3 This is a schematic cross-sectional view of the pump body portion according to a preferred embodiment of the present invention;

[0027] In the diagram: 1. Pump body; 2. Motor; 3. Pump shaft; 4. Support; 5. Pump cover; 6. Base; 7. Suction port; 8. Discharge port; 9. First-stage impeller; 10. Second-stage impeller; 11. Guide channel; 12. Self-priming liquid storage chamber; 13. Gas-liquid separation chamber; 14. Return hole; 15. Exhaust hole; 16. Anti-sway compartment structure; 17. Liquid supply area; 18. Flow stabilization structure; 19. Anti-vortex component. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0030] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] As shown in the figure, this application provides an energy-saving vertical self-priming two-stage centrifugal pump for ships, including a pump body 1, a motor 2 disposed above the pump body 1, a pump shaft 3 that is drivenly connected to the motor 2 and extends vertically into the pump body 1, and an inlet 7 and an outlet 8 disposed on the pump body 1.

[0033] A first-stage impeller 9 and a second-stage impeller 10 are axially spaced on the pump shaft 3. The outlet side of the first-stage impeller 9 is connected to the inlet side of the second-stage impeller 10 through the guide channel 11, so that the medium entering from the suction port 7 is pressurized by the first-stage impeller 9 and the second-stage impeller 10 in sequence and then discharged from the discharge port 8.

[0034] The pump body 1 is provided with a self-priming liquid storage chamber 12 and a gas-liquid separation chamber 13. The gas-liquid separation chamber 13 is connected to the outlet side of the first-stage impeller 9. The self-priming liquid storage chamber 12 is connected to the inlet side of the first-stage impeller 9 through a return channel. The gas phase region of the gas-liquid separation chamber 13 is connected to the exhaust port.

[0035] The first-stage impeller 9 drives the liquid in the self-priming storage chamber 12 to form a gas-liquid mixture with the intake gas. After the gas-liquid mixture enters the gas-liquid separation chamber 13, the separated liquid returns to the first-stage impeller 9 through the return channel, and the separated gas is discharged through the exhaust port. After the intake pipeline is filled with liquid, the first-stage impeller 9 and the second-stage impeller 10 are driven by the same motor 2 through the pump shaft 3 and continuously pressurized through the guide channel 11, thereby completing self-priming and two-stage conveying without setting an independent air pumping power source.

[0036] This invention utilizes the same motor 2 and the same pump shaft 3 to establish a continuous hydraulic link of first-stage self-priming—gas-liquid separation—liquid reflux—interstage transport—sub-stage pressurization. During the start-up phase, the first-stage impeller 9 completes gas-liquid mixing and exhaust with the help of the pre-stored liquid in the pump. After the suction pipe is filled with liquid, the flow path originally used for self-priming is naturally connected to the main flow path of the two-stage pressurization. The second-stage impeller 10 continues to pressurize based on the first-stage impeller 9. Thus, the power required for self-priming and the power required for two-stage transport are both provided by the same power source, reducing the need for independent air extraction devices and their auxiliary drive components, while maintaining the compact axial arrangement of the vertical pump.

[0037] Example 1:

[0038] The pump body 1 serves as the mounting base for the entire machine's pressure bearing and hydraulic flow channel. Its upper end is fixedly connected to the pump cover 5, and its lower end is fixedly connected to the base 6. The base 6 is used to fix the entire machine on the ship's equipment foundation. The motor 2 is located above the pump body 1 and is fixedly mounted on the bracket 4. The bracket 4 is fixedly connected to the upper part of the pump cover 5. The motor 2, bracket 4, pump cover 5, pump body 1, and base 6 are arranged vertically in sequence, thus forming a vertical overall structure in which the upper power zone and the lower hydraulic zone are separated. A fan cover can be installed on the upper part of the motor 2, and a junction box can be installed on the side to complete the heat dissipation protection and electrical connection of the motor 2, respectively.

[0039] The pump shaft 3 is connected to the output end of the motor 2 and extends vertically through the bracket 4 and the pump cover 5 into the pump body 1. A bearing seat is provided between the bracket 4 and the pump cover 5. The bearing seat is sleeved on the outside of the pump shaft 3 to provide radial and axial support for the pump shaft 3. A mechanical seal is provided between the bearing seat and the pump cover 5. The mechanical seal is arranged around the pump shaft 3 to close the position where the pump shaft 3 passes through the pump cover 5, thereby isolating the upper transmission area from the conveying medium inside the pump body 1.

[0040] The first-stage impeller 9 and the second-stage impeller 10 are both coaxially fixed on the pump shaft 3 and spaced apart along the axial direction of the pump shaft 3. The first-stage impeller 9 is located on the side of the second-stage impeller 10 closer to the pump cover 5. The two impellers are synchronously driven by the same motor 2, so that there are no speed matching and start-stop timing problems caused by independent power sources between the two stages. The first-stage impeller 9 is mainly responsible for starting self-priming, gas-liquid mixing and initial pressurization, while the second-stage impeller 10 is mainly responsible for further pressurization after the suction pipeline is filled with liquid.

[0041] The flow guiding channel 11 is located between the first-stage impeller 9 and the second-stage impeller 10, and includes an inlet section connected to the outlet side of the first-stage impeller 9, a transition flow guiding section for changing the fluid flow direction, and an outlet section connected to the inlet side of the second-stage impeller 10. The transition flow guiding section extends along the outer circumference of the pump shaft 3, causing the rotating fluid output from the first-stage impeller 9 to be redirected and guided as it transfers axially to the second-stage impeller 10. This interstage flow guiding structure utilizes the annular space around the vertical pump shaft 3 and shortens the external piping between the two stages, allowing the outlet side of the first-stage impeller 9 to directly form a continuous hydraulic connection with the inlet side of the second-stage impeller 10.

[0042] The suction port 7 and the discharge port 8 are respectively located on opposite sides of the pump body 1. The suction port 7 is connected to the inlet side of the first-stage impeller 9 through the suction flow channel inside the pump body 1, and the discharge port 8 is connected to the outlet side of the second-stage impeller 10. Therefore, after the pump enters the stable liquid delivery state, the main delivery medium flows sequentially along the suction port 7 - first-stage impeller 9 - guide channel 11 - second-stage impeller 10 - discharge port 8, forming a two-stage series booster main flow path.

[0043] Both the self-priming liquid storage chamber 12 and the gas-liquid separation chamber 13 are formed inside the pump body 1 and arranged on the outer periphery of the first-stage impeller 9 and the second-stage impeller 10. The gas-liquid separation chamber 13 is located above and communicates with the self-priming liquid storage chamber 12, so that the lower part of the gas-liquid separation chamber 13 forms a liquid collection area and the upper part forms a gas collection area. One end of the return channel communicates with the liquid collection area of ​​the self-priming liquid storage chamber 12 and the gas-liquid separation chamber 13, and the other end communicates with the inlet side of the first-stage impeller 9. The exhaust port is set at the top of the gas-liquid separation chamber 13, with its inner end communicating with the gas collection area and its outer end communicating with the outside of the pump body 1, and is higher than the communication position between the return channel and the liquid storage area. Thus, a self-priming circulation flow path is formed inside the pump body 1 that runs parallel to the two-stage main conveying flow path and participates in the operation during the start-up phase.

[0044] After shutdown, a certain amount of liquid remains in the lower part of the self-priming liquid storage chamber 12 and the gas-liquid separation chamber 13. When restarted, the motor 2 drives the first-stage impeller 9 and the second-stage impeller 10 to rotate simultaneously through the pump shaft 3. The first-stage impeller 9 first obtains circulating liquid through the return channel. Under the action of the first-stage impeller 9, the circulating liquid mixes with the air in the suction channel to form a gas-liquid mixture, which is then sent into the gas-liquid separation chamber 13. After the gas-liquid mixture enters the relatively expanded gas-liquid separation space, the flow rate decreases. The gas migrates to the upper gas collection area and is discharged through the exhaust port, while the liquid collects in the lower liquid area and returns to the first-stage impeller 9 through the return channel.

[0045] As the aforementioned gas-liquid mixing-separation-reflux process continues, the air in the suction pipe gradually decreases, and the liquid on the suction port 7 side is gradually lifted and enters the first-stage impeller 9. When the suction pipe is basically filled with liquid, the working medium of the first-stage impeller 9 gradually transitions from a high-gas-content mixture to a liquid-dominant medium. Its output enters the second-stage impeller 10 through the guide channel 11. The second-stage impeller 10 further increases the medium pressure and outputs it through the discharge port 8. In this way, the self-priming cycle is not independent of the two-stage conveying, but rather uses the same first-stage impeller 9 and the same internal flow channel of the pump to complete the continuous switching from the exhaust self-priming state to the two-stage pressurization state.

[0046] Thus, motor 2 and pump shaft 3 drive both the gas-liquid mixing during the self-priming stage and the dual-stage pressurization during the normal stage; the self-priming storage chamber 12, the gas-liquid separation chamber 13 and the return channel establish the circulating liquid conditions required for self-priming of the first-stage impeller 9, and once the first-stage impeller 9 establishes a stable liquid inlet, it directly supplies liquid to the second-stage impeller 10 through the guide channel 11. Therefore, there is no need to set up a separate drive source, reducing auxiliary energy consumption, installation space and maintenance components, and making the self-priming function and high-head conveying function of the vertical two-stage pump form the same power chain and hydraulic chain.

[0047] Example 2:

[0048] Based on Example 1, this embodiment further explains the self-priming liquid storage chamber 12, the return hole 14, and the gas-liquid separation exhaust hole 15 under special working conditions such as ship rolling, pitching, continuous tilting, and intermittent air intake at low liquid levels.

[0049] This embodiment is based on the basic vertical two-stage self-priming structure formed in Embodiment 1. Further structural improvements are made to address the problems of unstable self-priming circulation caused by changes in the liquid storage position inside the pump body 1 due to the hull's rolling, pitching, and continuous tilting during actual ship operation, as well as the problem of intermittent air intake at the suction port 7 when the pumped liquid is at a low level.

[0050] Specifically, when the ship is in a stable attitude and the inlet 7 is continuously submerged in the liquid, the liquid in the self-priming storage chamber 12 can be kept in a relatively stable position. The first-stage impeller 9 continuously obtains circulating liquid through the return hole 14. The first-stage impeller 9 mixes the circulating liquid with the air in the suction pipe and delivers it to the gas-liquid separation chamber 13. The gas is discharged through the exhaust hole 15, and the liquid returns to the self-priming storage chamber 12 and the first-stage impeller 9, thereby forming a continuous self-priming cycle.

[0051] However, when the ship rolls, pitches, or tilts continuously, the pump body 1 changes attitude synchronously with the hull, and the liquid inside the pump body 1 shifts relative to the pump body 1 under the influence of gravity and inertia. At this time, if the liquid stored in the pump is concentrated in a single connected space, the liquid can easily migrate to the lower side of the pump body 1 in a short period of time, causing the liquid level in the higher side area to drop. For a vertical self-priming pump that relies on the return flow of the stored liquid to complete self-priming, the problem caused by this phenomenon is not only a decrease in the total amount of liquid stored in the pump, but also that the liquid originally present in the pump cannot continuously reach the inlet of the first-stage impeller 9, resulting in a decrease in the effective amount of stored liquid actually participating in the self-priming cycle.

[0052] Meanwhile, when the bilge water, ballast water, or other transported liquids drop to low levels, the submersion depth of the liquid above the intake 7 decreases. The ship's rolling motion further causes periodic changes in the instantaneous liquid level near the intake 7, gradually transforming the intake 7 from a state of continuous liquid intake to one of alternating intake of liquid, gas-containing liquid, large bubbles, and air plugs. After air enters the first-stage impeller 9, it occupies part of the flow space at the inlet and between the blades, reducing the effective liquid volume obtained by the first-stage impeller 9 and causing significant fluctuations in the flow rate, pressure, and gas content at the outlet of the first-stage impeller 9.

[0053] Therefore, this embodiment addresses the complex problem caused by the combined effects of hull attitude changes and intermittent air intake at low liquid levels. On the one hand, the circulating liquid in the pump shifts position due to the hull swaying; on the other hand, the suction port 7 continuously supplies new air to the first-stage impeller 9. When both factors are present, the first-stage impeller 9 cannot obtain stable circulating liquid and needs to continuously process the newly introduced air, making the self-priming cycle more prone to interruption.

[0054] To address the aforementioned issues, this embodiment forms a self-priming liquid storage chamber 12 and a gas-liquid separation chamber 13 around the first-stage impeller 9. An anti-sway compartment structure 16 is provided inside the self-priming liquid storage chamber 12, and a reflux hole 14 is provided between the self-priming liquid storage chamber 12 and the first-stage impeller 9. At the same time, an exhaust hole 15 is provided in the gas phase region of the gas-liquid separation chamber 13. The above structure forms a self-priming hydraulic region around the first-stage impeller 9 where liquid storage, reflux, gas-liquid separation, and exhaust are interdependent. This structurally restricts the overall migration of the stored liquid caused by the hull swaying and maintains the required circulating liquid and exhaust path for the first-stage impeller 9 during intermittent air intake at the inlet 7.

[0055] Specifically, the self-priming liquid storage chamber 12 is disposed inside the pump body 1 and located on the outer periphery of the first-stage impeller 9. The self-priming liquid storage chamber 12 forms a circumferentially extending liquid storage space around the first-stage impeller 9. The anti-shake compartment structure 16 is disposed inside the self-priming liquid storage chamber 12. The anti-shake compartment structure 16 includes multiple compartment partitions that are spaced apart along the circumference of the self-priming liquid storage chamber 12. The multiple compartment partitions divide the continuous liquid storage space into multiple liquid storage units distributed along the outer periphery of the first-stage impeller 9.

[0056] Each compartment bulkhead extends from the cavity wall of the self-priming liquid storage chamber 12 into the interior of the chamber, and obstructs the lateral movement of the liquid along the circumference of the self-priming liquid storage chamber 12. Adjacent liquid storage units are connected by balance holes located at the lower part of the compartment bulkhead. The balance holes maintain necessary liquid compensation between adjacent liquid storage units, while preventing large-scale influx of liquid from one liquid storage unit to another during rapid hull rolling.

[0057] Therefore, when the pump body 1 tilts to one side with the hull, the liquid level in the storage unit closer to the lower tilt side rises, while the liquid level in the storage unit located on the higher tilt side drops. Due to the restriction between the storage units by the compartmentalized bulkheads, the liquid in the storage unit located on the higher side will not all pass through the self-priming storage chamber 12 to concentrate on the lower side in a short period of time, thus keeping liquid in multiple circumferential positions.

[0058] The aforementioned structure alters the traditional monolithic liquid storage chamber, where liquid can freely migrate throughout the entire chamber. With a traditional monolithic liquid storage chamber, even if a significant amount of liquid remains inside the pump after the pump body 1 is tilted, it may become unusable because all the liquid concentrates on the side furthest from the return flow position. This embodiment utilizes multiple liquid storage units to spatially divide the liquid, transforming the centralized storage within the pump body 1 into a circumferentially distributed storage system.

[0059] Therefore, the anti-sway compartment structure 16 in this embodiment improves the effective liquid storage volume that the first-stage impeller 9 can actually obtain in the tilted state, rather than simply increasing the total liquid storage volume by expanding the volume of the pump body 1.

[0060] When the hull rolls periodically, the stored liquid moves back and forth with the change in attitude of the pump body 1. The compartment bulkhead continuously blocks the stored liquid from forming a large-scale circumferential inertial flow, which divides the large swaying that may have run through the entire self-priming storage chamber 12 into smaller liquid movements within each storage unit, reducing the overall swaying amplitude of the free surface of the stored liquid and the periodic impact of the liquid on the chamber wall.

[0061] The balance hole is located at the bottom of the compartment partition. The compensation of liquid between each liquid storage unit occurs in the low liquid phase region of the liquid storage area. Therefore, while maintaining the long-term balance of liquid volume in each liquid storage unit, the compartment partition will not lose its function of limiting rapid shaking.

[0062] Through the above structural relationship, the self-priming liquid storage chamber 12 and the anti-roll compartment structure 16 together form an anti-roll liquid storage system that can maintain multiple liquid reserves even as the ship's attitude changes, providing a basis for the subsequent return hole 14 to continuously supply liquid to the first-stage impeller 9.

[0063] At least a portion of each liquid storage unit is connected to the inlet side of the first-stage impeller 9 through multiple circumferentially distributed return branches. Each return branch can merge into a common return area before supplying liquid to the first-stage impeller 9, or they can be connected to the vicinity of the inlet of the first-stage impeller 9 respectively. When the hull tilts in a certain direction, the local liquid level of the high-side liquid storage unit may drop, but the return branches on the low side or in other directions can still keep the liquid submerged, thereby avoiding the immediate interruption of the entire self-priming cycle after a single return port is exposed to the liquid surface.

[0064] The reflux hole 14 is arranged between the self-priming liquid storage chamber 12 and the inlet of the first-stage impeller 9. The liquid inlet end of the reflux hole 14 is connected to the liquid phase region in the self-priming liquid storage chamber 12, and the liquid outlet end of the reflux hole 14 is connected to the inlet side of the first-stage impeller 9. Thus, during the rotation of the first-stage impeller 9, the liquid stored in the self-priming liquid storage chamber 12 is guided back to the inlet of the first-stage impeller 9.

[0065] The return hole 14 forms multiple liquid intake positions along the circumference of the self-priming liquid storage chamber 12, with each intake position corresponding to the liquid storage in a different circumferential region. When the hull tilts, the local liquid level on the higher tilt side drops, while the liquid on the lower tilt side and other circumferential regions still covers the corresponding return intake position. Therefore, the return hole 14 will not lose its overall liquid supply due to a local position being exposed above the liquid surface.

[0066] During the self-priming stage, the first-stage impeller 9 relies on the return liquid to form a gas-liquid mixture with the air entering from the suction port 7. As the return liquid continues to enter the first-stage impeller 9, the blades of the first-stage impeller 9 do work on the return liquid, giving it a high velocity. The return liquid then mixes with the incoming air inside the impeller, thus transforming the large volume of air that is difficult to directly transport by a centrifugal impeller into a gas-liquid mixture that can move with the liquid.

[0067] Therefore, the return hole 14 is the liquid basis for the continuous self-priming process. As long as the first-stage impeller 9 continues to receive return liquid, the newly entered air can be continuously carried away from the inlet of the first-stage impeller 9 by the circulating liquid, making it difficult for a large volume air pocket to continuously occupy the flow channel at the inlet of the first-stage impeller 9.

[0068] When the ship rolls, the anti-roll compartment structure 16 first restricts the overall migration of the liquid storage to the lower side, ensuring that a certain amount of liquid is retained in different circumferential positions; the return port 14 then draws circulating liquid from the liquid storage unit that still retains liquid. Thus, the anti-roll compartment structure 16 solves the problem of whether the liquid is still in a usable position, while the return port 14 solves the problem of how the liquid in a usable position continuously enters the first-stage impeller 9.

[0069] If there is only the anti-sway compartment structure 16 without a stable return path, the stored liquid, although retained in different locations, cannot effectively return to the first-stage impeller 9. If there are only multiple return locations but the stored liquid can still migrate rapidly as a whole within a large cavity, then multiple return locations may still simultaneously lose liquid coverage under a specific tilt state. In this embodiment, the cooperation between the anti-sway compartment structure 16 and the return hole 14 ensures both the space retention and continuous access to the liquid.

[0070] The gas-liquid separation chamber 13 is formed inside the pump body 1 and located on the outer periphery of the first-stage impeller 9. The gas-liquid separation chamber 13 is connected to the outlet of the first-stage impeller 9 and is also connected to the self-priming liquid storage chamber 12.

[0071] After the first-stage impeller 9 mixes the return liquid with the intake air, the gas-liquid mixture enters the gas-liquid separation chamber 13 from the outlet of the first-stage impeller 9. The gas-liquid separation chamber 13 forms an enlarged volume space relative to the blade flow channel of the first-stage impeller 9. After the gas-liquid mixture enters the gas-liquid separation chamber 13 from the high-speed flow channel of the first-stage impeller 9, its overall flow velocity decreases.

[0072] Since the density of gas is significantly less than that of liquid, under the influence of decreasing flow rate and gravity, the gas entering the gas-liquid separation chamber 13 is gradually released from the liquid and migrates to the upper gas phase region of the gas-liquid separation chamber 13, while the liquid gathers in the lower part of the gas-liquid separation chamber 13 and the self-priming liquid storage chamber 12.

[0073] A flow stabilizing structure 18 is installed inside the gas-liquid separation chamber 13. The flow guide baffle in the flow stabilizing structure 18 divides and guides the rotating gas-liquid flow discharged from the first-stage impeller 9, limiting the rotating flow at the outlet of the first-stage impeller 9 from continuing to form a large-scale circulation throughout the gas-liquid separation chamber 13. After the gas-liquid mixed medium passes through the flow stabilizing structure 18, the rotational speed decreases, and the velocity difference and density difference between the gas and liquid make it easier for bubbles to be released from the liquid.

[0074] Therefore, the flow stabilizing structure 18 in this embodiment first weakens the rotational motion entering the gas-liquid separation chamber 13, so that the gas-liquid mixing medium obtains more stable separation conditions; after the gas is separated from the liquid, the gas volume fraction in the liquid decreases, which further reduces the flow instability of the gas-liquid mixing medium.

[0075] When the ship is rolling, the free liquid surface in the gas-liquid separation chamber 13 tilts as the pump body 1 changes attitude. The anti-roll compartment structure 16 and the flow stabilizing structure 18 together restrict the formation of large-scale sloshing of the liquid throughout the entire chamber, making it less likely that the gas that has been separated from the liquid will be re-entrained by the liquid due to the violent reciprocating motion of the liquid.

[0076] Therefore, the gas-liquid separation chamber 13 not only undertakes the gas-liquid separation during the normal self-priming start-up phase, but also undertakes the phased centralized processing of the fresh air continuously entering the pump under the low liquid level intermittent air intake state.

[0077] The exhaust port 15 is located on the upper part of the pump body 1 and communicates with the gas phase region of the gas-liquid separation chamber 13. The exhaust port 15 includes a gas collection area located on the upper part of the gas-liquid separation chamber 13, a gas collection channel arranged around the gas-liquid separation chamber 13, multiple gas collection inlets formed at different circumferential positions along the gas collection channel, and a centralized exhaust port communicating with the gas collection channel.

[0078] Multiple gas collection inlets are connected to the upper regions of the gas-liquid separation chamber 13 at different circumferential positions. After the gas separated from the gas-liquid mixture enters the gas phase region of the gas-liquid separation chamber 13, it enters the gas collection channel from the gas collection inlet closest to the current gas accumulation position, and then is collected by the gas collection channel to the centralized exhaust port and discharged from the pump body 1.

[0079] When the hull is kept horizontal, multiple gas collection inlets are connected to the upper gas phase region of the gas-liquid separation chamber 13, and the gas is collected and discharged through the gas collection channel.

[0080] When the hull tilts to either side, the instantaneous free liquid surface of the gas-liquid separation chamber 13 tilts relative to the pump body 1, and the gas moves towards the relatively higher side of the pump body 1. At this time, the gas collection inlet located on the relatively higher side remains in the gas phase region and directly receives the gas accumulated at that location. Even if the gas collection inlet located on the relatively lower side is briefly covered by liquid, it will not cause the entire exhaust path to be interrupted.

[0081] Therefore, in this embodiment, the exhaust port 15 transforms the traditional fixed single exhaust position into a multi-position gas intake and centralized exhaust port 15 distributed along the circumference. After the hull attitude changes, the gas accumulation position in the gas-liquid separation chamber 13 changes, while the exhaust port 15 always has a gas collection inlet corresponding to the current gas accumulation position.

[0082] This structure solves the problems of traditional single exhaust ports, where gas is difficult to reach the exhaust port when the fixed exhaust port is no longer at its instantaneous high point during hull tilting, and where liquid rushing towards the fixed exhaust port can easily form a liquid seal, causing a sudden increase in exhaust resistance.

[0083] In this embodiment, the gas does not need to traverse the entire gas-liquid separation chamber 13 laterally to find a fixed exhaust point. Instead, after the gas accumulates, it directly enters the adjacent gas collection inlet, reducing the residence time of the gas in the chamber and lowering the possibility that the separated gas will be entrained into the liquid phase again by the liquid sloshing effect.

[0084] Under intermittent air intake conditions at low liquid levels, when the intake port 7 briefly draws in bubbles, air masses, or air plugs, the first-stage impeller 9 still uses the return liquid provided by each liquid storage unit to form a transportable gas-liquid mixture from the incoming air. After the gas-liquid mixture enters the gas-liquid separation area, the gas is discharged through a multi-directional gas collection path, and the liquid falls back to each liquid storage unit and continues to participate in the self-priming cycle. At this time, the compartmentalized liquid storage structure, the return port 14, and the exhaust port 15 do not solve the problems of liquid storage, return, and exhaust independently, but rather form a closed loop with each other. The compartments ensure the existence of the return liquid, which enables the first-stage impeller 9 to continuously deliver air to the separation area. Separation and exhaust allow the liquid to re-enter the liquid storage area.

[0085] In this embodiment, the working process under the combined effects of hull swaying and intermittent air intake at low liquid levels is as follows: when the suction inlet 7 remains fully submerged, the first-stage impeller 9 continuously draws in liquid from the suction inlet 7. At the same time, the liquid in the self-priming storage chamber 12 enters the first-stage impeller 9 through the return hole 14. At this time, the pump is in a stable liquid delivery state, and the gas content in the gas-liquid separation chamber 13 is low.

[0086] As the level of the transported liquid decreases, the instantaneous submersion depth above the suction inlet 7 decreases. When the hull tilts in a direction that lowers the liquid level near the suction inlet 7, the suction inlet 7 begins to entrain air, increasing the proportion of gas at the inlet of the first-stage impeller 9.

[0087] During this stage, the anti-sway compartment structure 16 maintains circulating liquid in multiple liquid storage units, and the return port 14 continues to deliver the circulating liquid to the first-stage impeller 9. The air entering from the suction port 7 will not stay directly at the inlet of the first-stage impeller 9 for a long time, but will form a gas-liquid mixture with the return liquid and be delivered by the first-stage impeller 9 to the gas-liquid separation chamber 13.

[0088] After the gas-liquid mixture enters the gas-liquid separation chamber 13, the flow stabilizing structure 18 weakens its rotational motion, causing the gas to be released from the liquid and converge towards the gas phase region. The exhaust port 15 collects the separated gas at different circumferential positions and discharges the gas through the centralized exhaust port.

[0089] The separated liquid re-enters the lower part of the gas-liquid separation chamber 13 and the self-priming liquid storage chamber 12 under the action of gravity, and returns to the first-stage impeller 9 again through the return hole 14. This forms a continuous closed loop of liquid storage retention—return supply—gas-liquid mixing—gas-liquid separation—gas discharge—liquid re-storage—re-return.

[0090] When the hull swings further, causing the intake 7 to draw in a large air mass or air block in a short period of time, the liquid flow rate obtained by the first-stage impeller 9 from the intake 7 will temporarily decrease. However, the liquid pre-reserved in the self-priming storage chamber 12 will still enter the first-stage impeller 9 through the return hole 14, so that the interior of the first-stage impeller 9 will not immediately become a state completely occupied by air.

[0091] Therefore, during this short period, the first-stage impeller 9 still has liquid as a gas transport carrier, which can continue to transfer the incoming gas to the gas-liquid separation chamber 13, instead of leaving a large volume of air stuck at the inlet of the first-stage impeller 9 for a long time.

[0092] When the hull swings back and the suction inlet 7 is fully submerged by liquid again, the amount of liquid entering the first-stage impeller 9 increases rapidly. The gas that was previously left in the gas-liquid separation chamber 13 continues to be discharged through the exhaust port 15, and the liquid in the self-priming storage chamber 12 is replenished. Each storage unit restores the liquid balance through the balance hole, and the pump smoothly returns from the high gas content operating state to the continuous liquid delivery state.

[0093] When the above process occurs repeatedly during multiple swaying cycles of the ship, this embodiment does not require a complete pump stop and re-priming process to be repeated every time air enters the inlet 7. Instead, by continuously maintaining effective liquid storage and continuous venting, the pump maintains self-priming conditions in the cycle of normal water intake - air intake - short-term air lock - re-water intake.

[0094] Therefore, when the ship's attitude changes, the shift in liquid position will not simultaneously cut off all return paths, nor will the shift in gas position simultaneously cut off all exhaust paths. This structure can transform the impact of hull rolling on the self-priming process from a single-point failure to multi-point redundancy, reducing the probability of repeated loss of priming caused by the exposure of a certain return position or the submersion of a certain exhaust position, and providing more continuous first-stage liquid supply conditions for subsequent two-stage stable pressurization.

[0095] Through the above structure, this embodiment solves the problem of unstable effective liquid storage position caused by hull swaying. The anti-sway compartment structure 16 keeps the liquid in the self-priming liquid storage chamber 12 in multiple circumferential liquid storage units, reducing the degree to which all the liquid migrates to the lower side of the pump body 1 at the same time. The return hole 14 obtains circulating liquid from different circumferential liquid phase positions, so that the first stage impeller 9 can still obtain the liquid required to maintain self-priming after the pump body 1 tilts.

[0096] Secondly, this embodiment solves the problem of air binding in the first-stage impeller 9 under intermittent air intake conditions at low liquid levels. By continuously introducing reflux liquid into the first-stage impeller 9, the incoming air always has a liquid carrier, reducing the probability that large air masses occupy the impeller inlet and blade flow channel for a long time.

[0097] Furthermore, this embodiment solves the problem of the fixed exhaust position failing due to the hull swaying. The exhaust port 15 continuously corresponds to the instantaneous high side of the gas-liquid separation chamber 13 through multiple circumferential gas collection inlets, so that the exhaust process no longer depends on a certain fixed geometric position of the pump body 1.

[0098] Furthermore, the anti-sway compartment structure 16, the return port 14, the gas-liquid separation chamber 13, the flow stabilizing structure 18, and the exhaust port 15 form a continuous hydraulic closed loop. The anti-sway compartment structure 16 retains the liquid, the return port 14 utilizes the retained liquid, the first-stage impeller 9 uses the return liquid to transport air, the gas-liquid separation chamber 13 re-separates the liquid, and the exhaust port 15 truly removes the gas from the pump body 1. The separated liquid becomes the subsequent return liquid again.

[0099] Therefore, the above structure generates a continuous synergistic effect, which enables the pump to maintain the continuity of self-priming cycle even when the hull attitude changes periodically and the suction port 7 is periodically air-intaked, reducing the repeated establishment and disappearance of outlet pressure, and shortening the time required to restore stable liquid supply after the suction port 7 is re-submerged.

[0100] Example 3:

[0101] Based on Example 2, this embodiment further describes the provision of an independent liquid supply area 17 between the first-stage impeller 9 and the second-stage impeller 10, and the provision of a residual gas return and flow stabilization structure 18.

[0102] In a typical two-stage centrifugal pump, the first-stage impeller 9 and the second-stage impeller 10 are connected in series. The medium generated at the outlet of the first-stage impeller 9 directly enters the second-stage impeller 10 through the guide channel 11. When the first-stage impeller 9 draws in a stable liquid, the above-mentioned series structure can achieve continuous pressurization.

[0103] However, under the intermittent air intake condition of low liquid level in the ship targeted by this application, the outlet medium of the first-stage impeller 9 is not a stable single-phase liquid, but a gas-liquid mixture with varying gas content over time. Especially when the inlet 7 briefly draws in large air masses or airlocks, the outlet of the first-stage impeller 9 will experience a short-term decrease in flow rate, an increase in gas content, and a decrease in pressure.

[0104] If the first-stage impeller 9 and the second-stage impeller 10 are kept in a normal direct connection state, the high gas content medium discharged from the first-stage impeller 9 will directly reach the inlet of the second-stage impeller 10 along the guide channel 11.

[0105] The second-stage impeller 10 is mainly responsible for further pressurizing the liquid, and its normal pressurization requires a continuous liquid at the inlet. When a large amount of air enters the second-stage impeller 10, the gas occupies the inlet and blade flow channel of the second-stage impeller 10, which reduces the effective working area of ​​the second-stage impeller 10 on the liquid, resulting in a decrease in the second-stage head, fluctuations in outlet pressure, and air binding.

[0106] At the same time, the resumption of water intake by the first-stage impeller 9 does not mean that the second-stage impeller 10 can resume immediately. The gas that has entered the inlet of the second-stage impeller 10 and the high point between stages is still stuck near the second stage. Therefore, there is a time difference between the first stage resuming liquid intake and the second stage still accumulating gas.

[0107] This time difference causes significant asynchrony in the recovery process of the two-stage pump. When the residual gas is suddenly pushed out of the second stage by the liquid, the second-stage impeller 10 may re-establish a higher pressure in a short period of time, resulting in a sudden increase in outlet pressure.

[0108] Therefore, this embodiment solves the problem of how to allow the first-stage impeller 9 to continue to undertake the gas-liquid mixing and transport task while minimizing the direct impact of the large air mass and high gas content disturbance generated by the first-stage impeller 9 on the second-stage impeller 10.

[0109] Therefore, in this embodiment, a liquid supply area 17 is provided between the first-stage impeller 9 and the second-stage impeller 10, and a return channel and a flow stabilizing structure 18 are provided so that the gas and liquid move along different migration paths before entering the second-stage impeller 10.

[0110] The liquid supply area 17 is located on the liquid phase side of the gas-liquid separation chamber 13. The liquid inlet position of the liquid supply area 17 is lower than the main gas accumulation area in the gas-liquid separation chamber 13. The outlet of the liquid supply area 17 is connected to the inlet of the second-stage impeller 10.

[0111] The lower part of the liquid supply area 17 is connected to the liquid phase area where the separated liquid is located. When the gas-liquid mixture discharged from the first-stage impeller 9 enters the gas-liquid separation chamber 13, the large volume of gas moves towards the gas phase area, and the separated liquid enters the lower liquid phase area. The second-stage impeller 10 obtains liquid from the lower liquid phase area through the liquid supply area 17. In this way, a gas barrier area is formed between the first-stage impeller 9 and the second-stage impeller 10 using the liquid itself.

[0112] In this embodiment, the liquid seal does not completely isolate the two stages through independent mechanical valves. Instead, a liquid layer is formed between the liquid inlet position of the liquid supply area 17 and the free liquid surface of the gas-liquid separation chamber 13, so that the path that the air mass must take to directly enter the second-stage impeller 10 from the gas phase region is blocked by continuous liquid.

[0113] The gas, under the influence of buoyancy, tends to move towards the upper part of the gas-liquid separation chamber 13, while the liquid intake position of the second-stage impeller 10 is located in the lower liquid phase region. Therefore, the natural migration direction of the gas is separated from the main liquid intake direction of the second-stage impeller 10. This structure achieves spatial separation between the gas migration path and the subsequent liquid supply path.

[0114] The liquid supply area 17 simultaneously forms a short-term liquid buffer space before the inlet of the second-stage impeller 10. Under normal liquid supply conditions, the first-stage impeller 9 continuously supplies liquid to the gas-liquid separation chamber 13, and the liquid supply area 17 is continuously replenished with liquid. The second-stage impeller 10 obtains stable liquid from this area.

[0115] When the suction inlet 7 briefly draws in the air plug, and the instantaneous liquid flow rate of the first-stage impeller 9 decreases, the amount of new liquid replenished by the first-stage impeller 9 to the gas-liquid separation chamber 13 decreases synchronously. However, the liquid that was previously stored in the lower part of the gas-liquid separation chamber 13 and in the liquid supply area 17 will not disappear instantly. During this stage, the second-stage impeller 10 continues to obtain stored liquid from the liquid supply area 17, so that the instantaneous flow rate change of the second-stage impeller 10 lags behind the instantaneous flow rate change of the first-stage impeller 9. Therefore, the short-term flow rate decrease of the first-stage impeller 9 will not be transmitted to the second-stage impeller 10 in the same and synchronous manner.

[0116] The liquid seal solves the problem of preventing atmospheric clouds from entering the second stage as much as possible, and the buffering effect solves the problem that the second stage still has a liquid source when the first stage is temporarily insufficient. Both effects are achieved by the same liquid supply area 17. Therefore, this structure forms a liquid storage buffer while using the liquid itself to form a gas barrier.

[0117] When a short-term gas blockage occurs at the inlet 7, causing a momentary drop in the liquid supply to the first-stage impeller 9, the liquid pre-reserved in the lower part of the gas-liquid separation zone and the liquid supply zone 17 can continue to provide a short-term buffer to the second-stage impeller 10. This allows the second-stage impeller 10 to not be completely synchronized with the momentary drop in the flow rate of the first-stage impeller 9. This buffering effect works in conjunction with the gas isolation effect: the liquid seal reduces the proportion of gas entering the second stage, while the buffer reduces the transient fluctuations in the inlet flow rate of the second stage.

[0118] One end of the return channel is connected to the gas accumulation area above the inlet of the second-stage impeller 10, and the other end is connected to the upper gas phase area of ​​the gas-liquid separation chamber 13. The return channel forms a gas return path independent of the two-stage main conveying channel.

[0119] Although the liquid supply area 17 prevents large air masses from directly entering the second-stage impeller 10, a small number of tiny bubbles still remain in the separated liquid. After entering the liquid supply area 17 with the liquid, these bubbles gradually accumulate at the upper part of the inlet of the second-stage impeller 10 during the flow process.

[0120] The gas that has been gathered enters the return channel under the combined action of buoyancy and the pressure difference between the second-stage inlet area and the gas-liquid separation chamber 13, and returns to the upper part of the gas-liquid separation chamber 13 along the return channel. The gas that returns to the gas-liquid separation chamber 13 re-enters the exhaust port 15 and is finally discharged from the pump body 1.

[0121] Therefore, a small amount of gas entering the vicinity of the second-stage inlet does not need to rely on the second-stage impeller 10 to force it into the blade flow channel, nor does it need to wait for a large amount of liquid to push the gas mass out along the outlet 8. Instead, after the gas accumulates, it leaves the second-stage inlet directly along a dedicated return path.

[0122] This structure changes the migration direction of the residual gas. In a typical series two-stage structure, the gas entering the next stage continues to move downstream along the direction of the first-stage impeller 9, the interstage channel, the second-stage impeller 10, and the outlet 8. In this embodiment, after the residual gas enters the high-level area of ​​the second-stage inlet, it returns to the upstream gas processing area along the second-stage inlet gas accumulation area, the return channel, the gas-liquid separation chamber 13, and the exhaust port 15.

[0123] Therefore, the liquid continues to move towards the second-stage impeller 10 and the outlet 8, while the gas returns to the gas-liquid separation chamber 13, forming a separation between the main liquid transport path and the residual gas removal path.

[0124] The flow stabilizing structure 18 is respectively set in the gas-liquid separation area on the outer periphery of the first-stage impeller 9 and between the liquid supply area 17 and the inlet of the second-stage impeller 10. It serves as a flow guide baffle on the outer periphery of the first-stage impeller 9 and is also part of the anti-sway compartment structure 16. The flow guide baffle divides the self-priming liquid storage chamber 12 into multiple liquid storage units on the one hand, and circumferentially divides the rotating gas-liquid flow output by the first-stage impeller 9 on the other hand.

[0125] The medium at the outlet of the first-stage impeller 9 has a strong rotational component. If this rotating flow directly enters the larger gas-liquid separation chamber 13, it is easy to continue to form a large-scale circulation in the chamber, causing the liquid free surface to tumble and re-enter the already separated gas.

[0126] The flow stabilizing structure 18 divides the large-scale rotating flow into multiple local flow regions and restricts the continuous rotation of the fluid throughout the cavity, so that the liquid movement in the gas-liquid separation cavity 13 gradually stabilizes. Therefore, the same flow guide baffle simultaneously undertakes the functions of anti-shaking liquid storage and gas-liquid flow stabilization.

[0127] The flow guide structure set at the interstage liquid supply position adjusts the direction of the liquid before it enters the second stage impeller 10. After passing through the interstage guide vanes, the liquid from different positions in the liquid supply area 17 enters the second stage impeller 10 along the direction close to the designed inlet of the second stage impeller 10.

[0128] In this way, the liquid supply area 17 solves the problems of gas isolation and liquid supply buffering, and the interstage guide structure further solves the problem of uneven flow direction when the liquid enters the second stage impeller 10 from the buffer area. Together, they improve the inlet conditions of the second stage impeller 10.

[0129] The suction port 7 is located on one side of the pump body 1. The anti-swirling component 19 is installed between the suction port 7 and the suction flow channel inside the pump body 1. The anti-swirling component 19 extends into the suction flow channel along the axial direction of the suction port 7, and a filtration area with multiple liquid passage holes is formed on its outer periphery. After the external liquid enters the suction port 7, it first passes through the anti-swirling component 19. Larger solid impurities in the liquid are blocked outside the filtration area. The filtered liquid enters the pump body 1 and flows to the first stage impeller 9.

[0130] The anti-vortex component 19 simultaneously occupies the central region of the suction inlet 7 and disperses the liquid entering the suction inlet 7, preventing the liquid from concentrating and forming a high-velocity concentrated flow stream through the center of the suction inlet 7. When the external liquid level drops, the tendency for free liquid surface suction vortices to form near the suction inlet 7 increases. By dispersing the liquid flow on the suction section, the anti-vortex component 19 weakens the concentrated low-pressure state in the central region of the suction inlet 7, reducing the tendency for free liquid surface gas nuclei to penetrate into the pump body 1 along the center of the suction inlet 7.

[0131] Therefore, this component is not simply used as a filter screen, but also participates in improving the inlet conditions of the first-stage impeller 9 under low liquid level conditions. It forms a two-stage working relationship with the anti-shaking liquid storage structure in Example 2: the anti-swirl component 19 first reduces the degree of external air concentrated into the pump; even if some air still enters, the first-stage impeller 9, the self-priming liquid storage chamber 12, the return hole 14 and the gas-liquid separation structure continue to process the air that has entered the pump.

[0132] In this embodiment, under the combined conditions of ship swaying and intermittent air intake at low liquid levels, the pump operates according to the following process: During normal operation, liquid enters the pump body 1 from the suction port 7, passes through the anti-swirling component 19, and enters the first-stage impeller 9. The first-stage impeller 9 initially pressurizes the liquid and delivers it to the gas-liquid separation chamber 13.

[0133] Under normal liquid conditions, the gas-liquid separation chamber 13 only processes a small amount of trapped gas in the medium. Part of the separated liquid is kept in circulation as required by the first-stage impeller 9 through the return hole 14, while the other part enters the liquid supply area 17.

[0134] The liquid supply area 17 provides continuous liquid to the second-stage impeller 10. After the liquid adjusts its flow direction under the action of the flow stabilizing structure 18, it enters the second-stage impeller 10. The second-stage impeller 10 further pressurizes the medium and discharges it from the outlet 8. When the hull rolls and the inlet 7 experiences intermittent air intake, the gas content of the medium at the inlet of the first-stage impeller 9 increases. The anti-roll compartment structure 16 ensures that circulating liquid is still retained at different circumferential positions in the self-priming liquid storage chamber 12. The return hole 14 continues to replenish liquid to the first-stage impeller 9.

[0135] The first-stage impeller 9 mixes the newly introduced air with the circulating liquid and sends it into the gas-liquid separation chamber 13. Under the action of the flow stabilizing structure 18, the gas-liquid separation chamber 13 separates the gas and liquid. The gas enters the exhaust port 15 and is discharged from the pump body 1. The separated liquid flows downward into the liquid phase region. Part of it re-enters the self-priming liquid storage chamber 12 to maintain the circulation of the first-stage impeller 9, and the other part enters the liquid supply region 17.

[0136] Because the liquid supply zone 17 draws liquid from the liquid phase position after gas-liquid separation, the large air mass accumulated at the top will not directly enter the second-stage impeller 10 along the shortest path. When the suction inlet 7 briefly draws in a large air slug, causing a temporary decrease in the liquid supply to the first-stage impeller 9, the liquid supply zone 17 continues to supply liquid to the second-stage impeller 10 using the previously stored liquid. Therefore, the liquid supply to the second-stage impeller 10 will not be completely synchronized with the instantaneous decrease in the flow rate of the first-stage impeller 9.

[0137] A small amount of air entering near the second-stage inlet with the liquid accumulates in the higher region and returns to the gas-liquid separation chamber 13 through the return channel. This portion of gas re-enters the exhaust path instead of continuing to accumulate inside the second-stage impeller 10.

[0138] After the hull swings back and the inlet 7 regains continuous liquid, the liquid supply to the first-stage impeller 9 gradually resumes, the gas-liquid separation chamber 13 continues to discharge the previously residual gas, and the liquid supply area 17 is fully replenished with liquid again. At this time, the second-stage impeller 10 always maintains a certain liquid supply, and the residual gas at its inlet is discharged along the return channel. Therefore, the process of the second-stage impeller 10 recovering from the gas-containing condition to the stable liquid pressurization state is more continuous.

[0139] The above process forms a complete hydraulic link, including inlet 7 rectification and filtration, first-stage gas-containing transport, anti-shake liquid storage and circulation, gas-liquid separation, multi-directional exhaust, liquid seal gas isolation, interstage liquid buffer, second-stage stable pressurization, and residual gas return separation.

[0140] Through the above structure, this embodiment further extends the anti-shaking self-priming capability formed in Embodiment 2 to the second-stage impeller 10. The liquid supply region 17 separates the operating characteristics of the first-stage impeller 9 (allowing it to handle high-gas-content media) from the operating requirements of the second-stage impeller 10 (requiring a stable liquid inlet), ensuring that the two impellers no longer experience the same instantaneous gas content. The liquid supply region 17 utilizes the separated liquid to form a gas barrier, causing large gas masses to accumulate in the upper part of the gas-liquid separation chamber 13, while the second-stage impeller 10 draws liquid from the lower liquid phase region, structurally altering the direct path of the gas masses into the second-stage impeller 10. The liquid supply region 17 maintains a certain liquid volume, continuing to supply liquid to the second-stage impeller 10 when the first-stage impeller 9 experiences an instantaneous drop in liquid supply, thereby reducing the direct transmission of flow fluctuations from the first stage to the second stage. The return channel provides an independent removal path for the small amount of air entering the second-stage inlet region, preventing a small amount of gas from gradually accumulating over multiple swaying cycles and eventually forming a large gas pocket. The flow stabilizing structure 18 improves the flow state of the gas-liquid mixture at the outlet of the first-stage impeller 9 in the gas-liquid separation chamber 13, and improves the liquid flow direction before entering the second-stage impeller 10 in the liquid supply area 17, so that gas separation and stable liquid delivery promote each other. The anti-vortex component 19 reduces the degree of concentrated suction vortex formed at the suction inlet 7 under low liquid level conditions, reducing the large volume air mass entering the first-stage impeller 9 from the source; the anti-shake liquid storage, separation, exhaust, liquid seal and return structure inside the pump continues to process the air that has entered the system.

[0141] Therefore, this embodiment forms a continuous anti-gas disturbance system from the inlet 7 to the second-stage impeller 10, rather than adding a separate exhaust or liquid storage structure at a certain local location.

[0142] Ultimately, in this embodiment, when hull swaying, low liquid level, and intermittent air intake coexist, the first-stage impeller 9 continues to perform self-priming and gas-liquid mixing, while maintaining the lower gas-liquid supply conditions required by the second-stage impeller 10, thereby reducing second-stage gas binding, sudden drop in outlet pressure, and pressure shock during the recovery process.

[0143] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An energy-saving vertical self-priming two-stage centrifugal pump for ships, comprising: The pump body, the motor disposed above the pump body, the pump shaft connected to the motor and extending vertically into the pump body, and the suction port and discharge port disposed on the pump body, are characterized in that: The pump shaft is provided with a first-stage impeller and a second-stage impeller spaced apart along the axial direction. The outlet side of the first-stage impeller is connected to the inlet side of the second-stage impeller through a flow guide channel, so that the medium entering from the suction port is pressurized by the first-stage impeller and the second-stage impeller in sequence and then discharged from the discharge port. The pump body is provided with a self-priming liquid storage chamber and a gas-liquid separation chamber. The gas-liquid separation chamber is connected to the outlet side of the first stage impeller. The self-priming liquid storage chamber is connected to the inlet side of the first stage impeller through a reflux channel. The gas phase region of the gas-liquid separation chamber is connected to the exhaust port. The first-stage impeller drives the liquid in the self-priming storage chamber to form a gas-liquid mixture with the intake gas. After the gas-liquid mixture enters the gas-liquid separation chamber, the separated liquid returns to the first-stage impeller through the return channel, and the separated gas is discharged through the exhaust port. After the intake pipeline is filled with liquid, the first-stage impeller and the second-stage impeller are jointly driven by the same motor through the pump shaft and continuously pressurized through the guide channel to complete self-priming and two-stage delivery without setting an independent air pumping power source.

2. The energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 1, characterized in that: The motor is fixedly mounted on the bracket, which is fixedly connected to the top of the pump cover; the pump shaft passes through the bracket and the pump cover in sequence, and the first-stage impeller and the second-stage impeller are both coaxially fixed on the pump shaft so as to be synchronously driven by the motor.

3. The energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 2, characterized in that: A bearing seat is provided between the bracket and the pump cover. The bearing seat is sleeved on the outside of the pump shaft and is used to support the pump shaft. A mechanical seal is provided between the bearing seat and the pump cover. The mechanical seal is arranged around the pump shaft to seal the position where the pump shaft passes through the pump cover.

4. The energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 1, characterized in that: The first-stage impeller is located on the side of the second-stage impeller near the pump cover. The flow guide channel is disposed between the first-stage impeller and the second-stage impeller, and connects the outlet side of the first-stage impeller and the inlet side of the second-stage impeller along the axial direction of the pump shaft.

5. An energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 4, characterized in that: The flow guiding channel includes an inlet section connected to the outlet side of the first stage impeller, a transition flow guiding section for changing the fluid flow direction, and an outlet section connected to the inlet side of the second stage impeller; the transition flow guiding section extends along the outer periphery of the pump shaft to smoothly guide the rotating fluid output from the first stage impeller to the inlet side of the second stage impeller.

6. An energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 1, characterized in that: Both the self-priming liquid storage chamber and the gas-liquid separation chamber are formed in the pump body and located on the outer periphery of the first-stage impeller and the second-stage impeller. The gas-liquid separation chamber is located above the self-priming liquid storage chamber and communicates with it, so that the lower part of the gas-liquid separation chamber forms a liquid collection area and the upper part forms a gas collection area.

7. An energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 6, characterized in that: The return channel is a single return channel located within the pump body. One end of the return channel is connected to the liquid collection area of ​​the self-priming storage chamber and / or the gas-liquid separation chamber, and the other end is connected to the inlet side of the first-stage impeller, so as to replenish the circulating liquid to the first-stage impeller during the self-priming start-up phase.

8. An energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 6, characterized in that: The exhaust port is a single exhaust port located at the top of the gas-liquid separation chamber. The inner end of the exhaust port is connected to the gas collection area, and the outer end is connected to the outside of the pump body. The exhaust port is higher than the connection position between the return channel and the self-priming liquid storage chamber or the gas-liquid separation chamber.

9. An energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 5, characterized in that: The suction port and discharge port are respectively located on opposite sides of the pump body. The suction port is connected to the inlet side of the first-stage impeller through the suction flow channel in the pump body, and the discharge port is connected to the outlet side of the second-stage impeller, so that the main conveying medium flows sequentially along the suction port, the first-stage impeller, the guide channel, the second-stage impeller and the discharge port.

10. An energy-saving vertical self-priming two-stage centrifugal pump for ships according to claim 2, characterized in that: The motor is provided with a fan cover on the upper part and a junction box on the side; the upper end of the pump body is fixedly connected to the pump cover and the lower end is fixedly connected to the base. The motor, bracket, pump cover, pump body and base are arranged vertically in sequence.

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