Self-priming centrifugal seawater pump

Abstract

This invention provides a self-priming centrifugal seawater pump, comprising a pump body, a pump cover, and a pump shaft. A copper alloy main impeller and a rubber auxiliary impeller are mounted on the pump shaft. An inlet distribution plate is mounted on one side of the rubber auxiliary impeller near the copper alloy main impeller, and an outlet distribution plate is mounted on the other side. An annular bushing is fitted around the outer circumference of the rubber auxiliary impeller. The inner bore of the rubber auxiliary impeller and the bushing are eccentrically fitted, which causes the rubber auxiliary impeller to deform and interfere with the inner bore of the bushing to achieve radial sealing. The inlet distribution plate, the rubber auxiliary impeller, and the outlet distribution plate are axially fitted together, and axial sealing is achieved by pressing the two end faces of the rubber auxiliary impeller. A balance hole is provided on the rear cover plate of the copper alloy main impeller. An inlet waist-shaped groove is provided on the inlet distribution plate, and an outlet waist-shaped groove is provided on the outlet distribution plate. A central hole is provided on the pump cover, and an outlet pipe including an outlet check valve is connected to the central hole. The above structures are connected in sequence to form a self-priming chamber.

Description

Technical Field

[0001] This invention belongs to the field of pump technology, specifically relating to a self-priming centrifugal seawater pump, which is particularly suitable for cooling systems driven by the crankshaft of marine engines. Background Technology

[0002] In marine cooling systems, seawater pumps are used to draw water from below sea level and deliver it to the intercooler to cool the high-temperature fresh water flowing from the engine block and cylinder head. Existing seawater pumps mainly fall into the following categories:

[0003] 1. External or internal mixing self-priming centrifugal pump

[0004] This type of self-priming pump achieves its self-priming function by incorporating a liquid storage chamber and a gas-liquid separation chamber within the pump body, utilizing a cyclic process of gas-liquid mixing and separation. However, this type of self-priming pump has the following drawbacks:

[0005] Large size and complex structure: It requires the setting of special liquid storage chamber, gas-liquid separation chamber, reflux hole, etc., which leads to a significant increase in the axial or radial dimensions of the pump body and high requirements for installation space.

[0006] Not suitable for direct-drive installation on engine crankshaft: Due to the limited space at the output end of the engine crankshaft, large-volume self-priming pumps are difficult to install directly.

[0007] 2. Conventional copper alloy impeller centrifugal pump

[0008] This type of seawater pump uses a copper alloy impeller, which has the advantages of being resistant to seawater corrosion, having a compact structure, and high efficiency. However, it has a fundamental drawback—it lacks self-priming capability. Before starting, the pump body must be filled with seawater, and there must be no air in the inlet pipe.

[0009] In marine operations, when the hull tilts and the water intake is exposed above the sea level, air will enter the water intake pipe. At this time, the conventional centrifugal pump cannot vent the air on its own, causing the pump to fail to draw water, the cooling system to fail, and potentially leading to engine overheating.

[0010] 3. Rubber impeller seawater pump (flexible impeller pump)

[0011] This type of seawater pump uses an integral rubber impeller, achieving self-priming through the interference fit between the outer circumference of the impeller and the inner wall of the pump body, simultaneously performing water intake and drainage functions. Its advantages are strong self-priming capability and simple structure. However, its disadvantages are also prominent:

[0012] Flow rate decreases after rubber impeller wear: Since the interference fit of the outer circle of the rubber impeller is the key to ensuring self-priming and water delivery capacity, as the operating time increases (about 500 hours), the wear of the outer circle of the impeller leads to a reduction in the interference fit, and the pump's flow rate and head continue to decrease, failing to meet the requirements of the cooling system.

[0013] Frequent replacement: To ensure cooling performance, the rubber impeller needs to be replaced frequently, resulting in high maintenance costs and long downtime.

[0014] Single function: The rubber impeller performs both self-priming and water conveyance functions at the same time. Both functions are affected after wear, and there is a lack of functional redundancy.

[0015] In summary, existing seawater pump technology presents a difficult contradiction: if a metal impeller centrifugal pump is used, it lacks self-priming capability and is prone to failure due to air intake when the hull tilts; if a self-priming centrifugal pump (external / internal mixing type) is used, it is large in size, installation is limited, and wear of the self-priming components affects the overall pump performance; if a rubber impeller pump is used, the flow rate decreases after the impeller wears, requiring frequent replacement. Summary of the Invention

[0016] The technical problem to be solved by the present invention is to provide a compact, crankshaft-driven, self-priming centrifugal seawater pump that can meet the self-priming requirements of marine cooling systems and ensure that the main impeller flow rate does not decrease due to wear of the self-priming components during long-term operation.

[0017] To solve the above-mentioned technical problems, the technical solution of the present invention is: a self-priming centrifugal seawater pump, comprising a pump body, a pump cover, and a pump shaft. The pump body is provided with an inlet and an outlet. A copper alloy main impeller and a rubber auxiliary impeller are mounted on the pump shaft. An inlet distribution plate is mounted on one side of the rubber auxiliary impeller near the copper alloy main impeller, and an outlet distribution plate is mounted on the other side. An annular bushing is fitted around the outer circumference of the rubber auxiliary impeller. The rubber auxiliary impeller and the inner hole of the bushing are eccentrically fitted, which causes the rubber auxiliary impeller and the inner hole of the bushing to deform and interfere to achieve radial sealing. The inlet distribution plate, the rubber auxiliary impeller, and the outlet distribution plate are tightly fitted in the axial direction, and the rubber auxiliary impeller is pressed by the inlet distribution plate and the outlet distribution plate. The two end faces of the impeller are axially sealed; the rear cover plate of the copper alloy main impeller is provided with a balance hole, the inlet distribution plate is provided with an inlet waist-shaped groove, the outlet distribution plate is provided with an outlet waist-shaped groove, the pump cover is provided with a pump cover center hole, and the pump cover center hole is connected to an outlet pipe including an outlet check valve; the balance hole, the inlet waist-shaped groove, the adjacent blade spacing area of ​​the rubber auxiliary impeller, the outlet waist-shaped groove, the inner area of ​​the pump cover, and the outlet pipe are sequentially connected to form a self-priming chamber; seawater enters the pump body from the inlet, and after being pressurized by the rotation of the copper alloy main impeller, most of it is discharged from the outlet, and the other part enters the self-priming chamber through the balance hole on the rear cover plate of the copper alloy main impeller, and is then pressurized by the rotation of the rubber auxiliary impeller and discharged from the outlet pipe.

[0018] The working process and principle of the above-mentioned seawater pump are as follows: The pump shaft drives the copper alloy main impeller and the rubber auxiliary impeller to rotate synchronously, forming two seawater conveying paths that always work in parallel. The first conveying path: Seawater enters the pump body through the inlet, and after being pressurized by the rotation of the copper alloy main impeller, most of it is discharged into the central cooler from the outlet. The second conveying path: Another portion of the seawater enters the self-priming chamber through the balance hole on the rear cover plate of the copper alloy main impeller, and then enters the adjacent blade spacing area of ​​the rubber auxiliary impeller through the inlet waist-shaped groove. When the rubber auxiliary impeller rotates, its flexible blades cooperate with the eccentric bushing to generate a volume change, discharging the seawater into the central cooler through the outlet waist-shaped groove, the pump cover's central hole, the outlet check valve, and the outlet pipeline. The outlet check valve... The valve is only used to prevent seawater backflow in the second delivery path. When there is gas in the inlet pipe, the second delivery path simultaneously draws in the gas-liquid mixture and forces the gas out, achieving a self-priming and exhaust function. When there is no gas in the inlet pipe, the second delivery path and the first delivery path are connected in parallel to deliver seawater. The copper alloy main impeller can meet the predetermined minimum coolant requirement at the specified engine speed when working independently. The rubber auxiliary impeller increases the total delivery flow through the second delivery path when it is not worn. When worn, its self-priming and exhaust function decreases, but the copper alloy main impeller can still independently guarantee the minimum coolant requirement. The overall delivery performance is not affected by the wear state of the rubber auxiliary impeller.

[0019] Furthermore, the inlet distribution plate, outlet distribution plate, and bushing are provided with axially oriented limiting holes, and limiting pins are screwed into the upper end face of the pump cover. These limiting pins are sequentially inserted into the limiting holes on the inlet distribution plate, bushing, and outlet distribution plate. This prevents the aforementioned components from rotating with the rubber impeller.

[0020] In one embodiment, the pump cover is mounted on the pump body by fastening bolts, and an annular boss is provided on the inner side of the pump cover, the end face of the annular boss being in contact with the outer end face of the outlet distribution plate.

[0021] In one embodiment, the outer circle of the bushing is coaxially arranged with the outer circle of the copper alloy main impeller.

[0022] In one embodiment, the shaft hole of the rubber auxiliary impeller is provided with a keyway for installing a semi-circular key, which is connected to the water pump shaft to transmit torque; the shaft hole of the copper alloy main impeller is interference-fitted with the water pump shaft.

[0023] In one embodiment, a water seal, an oil seal, a first deep groove ball bearing, a bearing positioning sleeve, a second deep groove ball bearing, and a bore elastic retaining ring are sequentially assembled axially between the other end of the pump shaft and the connecting body.

[0024] In one embodiment, the rubber impeller includes multiple flexible blades that extend outward from the central hub in a star-shaped or radial pattern. The blades radially engage with the eccentric inner hole of the bushing, achieving radial sealing through blade deformation.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) Compact structure, suitable for direct crankshaft installation: There is no need to set up a separate large-volume liquid storage chamber and gas-liquid separation chamber. The self-priming chamber is integrated inside the pump body. The pump body size is comparable to that of a conventional centrifugal pump. It can be directly installed on the output end of the engine crankshaft, which solves the problems of large size and limited installation of existing self-priming pumps.

[0027] 2) Dual paths always in parallel, reliable self-priming: The two seawater delivery paths always work in parallel. When the inlet pipe contains gas, the second delivery path simultaneously draws out the gas-liquid mixture and forces it into the central cooler to quickly complete self-priming. When there is no gas in the inlet pipe, the second delivery path and the first delivery path work in parallel to deliver seawater and jointly provide cooling flow.

[0028] 3) Main function guaranteed, auxiliary function enhanced: The copper alloy main impeller can independently meet the minimum coolant requirement at the engine's specified speed. When the rubber auxiliary impeller is unworn, it adds extra flow, serving as a supplementary function; after the rubber auxiliary impeller wears, only the self-priming exhaust function decreases, but the copper alloy main impeller can still independently guarantee the minimum cooling requirement, and the overall conveying performance remains unaffected. This achieves structural and performance decoupling between the main conveying function and the self-priming auxiliary function.

[0029] 4) Fail-safe design and low maintenance cost: As a wear part, the rubber impeller's wear will not cause engine cooling system failure, only a weakening of its self-priming function. Since air intake into the intake pipe due to hull roll is an occasional occurrence, the actual working load of the rubber impeller is low, and its replacement cycle is much longer than that of conventional flexible impeller pumps (500 hours). Even if replacement is necessary, the rubber impeller can be quickly replaced simply by removing the pump cover, resulting in good manufacturability and low maintenance costs.

[0030] 5) Double sealing, high self-priming efficiency: The rubber impeller achieves radial sealing through eccentric interference and end face sealing through axial compression. The double sealing ensures the airtightness of the self-priming chamber, ensuring that sufficient vacuum can be established during the self-priming process and that the emptying speed is fast.

[0031] 6) Anti-rotation design for stable operation: The inlet distribution plate, outlet distribution plate and bushing are fixed by limit pins to prevent them from rotating with the rubber impeller, thus ensuring the stability of the self-priming chamber structure and the reliability of the self-priming function. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the external structure of the seawater pump in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the internal structure of the seawater pump in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the copper alloy main impeller structure in an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the rubber impeller structure in an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the rubber auxiliary impeller and bushing structure in an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the inlet distribution plate structure in an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the outlet distribution plate structure in an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the pump cover structure in an embodiment of the present invention;

[0040] The attached diagram is labeled as follows: 1. Pump body; 2. Copper alloy main impeller; 2a. Balance hole; 3. Inlet distribution plate; 3a. Inlet waist-shaped groove; 4. Rubber auxiliary impeller; 4a. Blade spacing area; 4b. Keyway; 5. Outlet distribution plate; 5a. Outlet waist-shaped groove; 6. Pump cover; 6a. Pump cover center hole; 6b. Annular boss; 6c. Inner area of ​​pump cover; 7. Bushing; 8. Outlet check valve; 8a. Outlet pipeline; 9. Fastening bolt; 10. Limit pin; 11. Semi-circular key; 12. Pump shaft; 13. Water seal; 14. Oil seal; 15. First deep groove ball bearing; 16. Bearing positioning sleeve; 17. Second deep groove ball bearing; 18. Hole elastic retaining ring; 19. Connecting body. Detailed Implementation

[0041] To facilitate understanding by those skilled in the art, the invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the invention.

[0042] It should be noted in advance that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly in this invention. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0043] Example 1

[0044] like Figures 1 to 8As shown, this embodiment provides a self-priming centrifugal seawater pump assembly, including a pump body 1, a pump cover 6, and a pump shaft 12. The pump body 1 has an inlet and an outlet at different external positions. The inlet of the pump body 1 is connected to an inlet pipe submerged below sea level, and the outlet is connected to a central cooler via a pipe. A copper alloy main impeller 2 and a rubber auxiliary impeller 4 are mounted on the pump shaft 12. The copper alloy main impeller 2 is made of a copper alloy resistant to seawater corrosion (such as ZCuZn16Si4 or ZCuAl10Fe3). An inlet distribution plate 3 is mounted on one side of the rubber auxiliary impeller 4 near the copper alloy main impeller 2, and an outlet distribution plate 5 is mounted on the other side. An annular bushing 7 is fitted around the outer circumference of the rubber auxiliary impeller 4. The outer circles of the above-mentioned parts are fitted with a small clearance to the inner hole of the pump body 1 to ensure coaxiality.

[0045] 1. Sealed structure

[0046] Radial sealing: The rubber auxiliary impeller 4 and the inner bore of the bushing 7 are eccentrically fitted. Specifically, the outer circle of the bushing 7 is coaxial with the outer circle of the copper alloy main impeller 2, while the axis of the inner bore of the bushing 7 has an eccentricity of 2.0 mm with the axis of the inner bore of the pump body 1. The outer circle of the rubber auxiliary impeller 4 is designed to theoretically fit the inner bore of the bushing 7. After assembly, a radial interference is formed between the outer circle of the rubber auxiliary impeller 4 and the inner bore of the bushing 7, with the interference controlled between 0.2 and 0.8 mm. Due to the elasticity of the rubber material, the blades of the rubber auxiliary impeller 4 undergo radial deformation, tightly fitting with the inner bore of the bushing 7, thus achieving radial sealing.

[0047] Axial sealing: The inlet distribution plate 3, rubber auxiliary impeller 4, and outlet distribution plate 5 are sequentially fitted together axially. An annular boss 6b is provided on the inner side of the pump cover 6, and the end face of the annular boss 6b fits against the outer side of the outlet distribution plate 5. The pump cover 6 is connected to the pump body 1 around its end face by fastening bolts 9. After tightening the bolts, the annular boss 6b presses against the outlet distribution plate 5, which in turn presses against the rubber auxiliary impeller 4 and the inlet distribution plate 3 in sequence, ensuring that the two end faces of the rubber auxiliary impeller 4 are tightly fitted against the inner sides of the inlet distribution plate 3 and the outlet distribution plate 5, respectively, achieving an axial seal. The axial clamping force is controlled by the bolt torque, aiming for slight deformation of the rubber auxiliary impeller 4 without damage.

[0048] 2. Self-priming cavity structure

[0049] The rear cover plate of the copper alloy main impeller 2 has multiple balance holes 8 (6 in this embodiment, evenly distributed along the circumference). The diameter of the balance hole 8 is determined by calculation based on the area of ​​the sealing ring gap. In this embodiment, the diameter of a single hole is 8~10mm.

[0050] An inlet waist-shaped groove 3a is provided on the inlet distribution plate 3, and an outlet waist-shaped groove 5a is provided on the outlet distribution plate 5. The inlet waist-shaped groove 3a and the outlet waist-shaped groove 5a are offset at a certain angle in the circumferential direction to ensure that the adjacent blade spacing area 4a of the rubber auxiliary impeller 4 can be connected to the inlet waist-shaped groove 3a and the outlet waist-shaped groove 5a in sequence.

[0051] The pump cover 6 has a central hole 6a, which is connected to an outlet pipe 8a. An outlet check valve 8 is installed on the outlet pipe 8a. The outlet check valve 8 is similar to a diaphragm check valve, which can be opened as long as there is a pressure difference on both sides. It is used to prevent seawater backflow and is not used to control the start and stop of the pipeline.

[0052] The six regions—the gap between the rear cover plate of the copper alloy main impeller 2 and the inlet distribution plate 3, the inlet waist-shaped groove 3a, the blade spacing area 4a of the rubber auxiliary impeller 4, the outlet waist-shaped groove 5a, the area between the outlet distribution plate 5 and the inner side of the pump cover 6, and the outlet pipeline 8a—are connected in sequence to form a self-priming chamber.

[0053] 3. Anti-rotation structure

[0054] To prevent the inlet distribution plate 3, bushing 7, and outlet distribution plate 5 from rotating with the rubber auxiliary impeller 4, limit holes are made at corresponding axial positions on the inlet distribution plate 3, bushing 7, and outlet distribution plate 5. A limit pin 10 is screwed into the upper end face of the pump cover 6. The part of the limit pin 10 that mates with the pump cover 6 is threaded for fastening, while the part of the limit pin 10 that passes through the limit holes on the outlet distribution plate 5, bushing 7, and inlet distribution plate 3 is a smooth rod structure, used to fix the above parts inside the pump body 1 so that they cannot rotate.

[0055] 4. Transmission Structure

[0056] The inner bore of the rubber auxiliary impeller 4 has a keyway 4b, which connects to the water pump shaft 12 via a semi-circular key 11 to achieve torque transmission. The inner bore of the copper alloy main impeller 2 is interference-fitted with the water pump shaft 12 and is fixed by heat fitting or press fitting. The outer side of the water pump shaft 12 has a spline, which mates with the spline sleeve at the engine output end, allowing the engine to directly drive the water pump shaft 12 to rotate.

[0057] 5. Sealing and Support Structure

[0058] On the other side of the copper alloy main impeller 2 (front cover plate side), a water seal 13, an oil seal 14, a first deep groove ball bearing 15, a bearing positioning sleeve 16, a second deep groove ball bearing 17, and a retaining ring 18 for the bore are sequentially assembled along the axial direction. The outer circles of the above parts are coaxially fitted with the inner hole of the connecting body 19. The water seal 13 and oil seal 14 are used to prevent seawater from leaking into the bearing cavity along the pump shaft; the deep groove ball bearings 15 and 17 are used to support the water pump shaft 12; the bearing positioning sleeve 16 is used to adjust the axial clearance of the bearing; and the retaining ring 18 for the bore is used for axial positioning of the bearing. The connecting body 19 is fixedly connected to the engine flywheel housing or bracket.

[0059] 6. Work Process

[0060] Under normal water supply conditions (no gas in the inlet pipe): The engine drives the water pump shaft 12 to rotate, causing the copper alloy main impeller 2 and the rubber auxiliary impeller 4 to rotate synchronously. Seawater enters the front cover plate of the copper alloy main impeller 2 through the pump body inlet. Under the centrifugal force of the main impeller, it is pressurized and discharged from the pump body outlet, entering the central cooler (first delivery path). At the same time, a small amount of seawater enters the self-priming chamber through the balance hole 2a on the rear cover plate of the copper alloy main impeller 2, and enters the adjacent blade spacing area 4a of the rubber auxiliary impeller 4 through the inlet waist-shaped groove 3a. The flexible blades of the rubber auxiliary impeller 4 cooperate with the eccentric bushing 7 to produce a volume change similar to that of a flexible impeller pump, pressurizing the seawater and discharging it into the central cooler (second delivery path) through the outlet waist-shaped groove 5a, the pump cover center hole 6a, the outlet check valve 8, and the outlet pipe 8a. The two paths always work in parallel, jointly providing cooling seawater to the central cooler. The outlet check valve 8 automatically opens under the pressure of the second delivery path, only preventing backflow when the machine stops.

[0061] Self-priming operation (inlet pipe contains gas): When the ship tilts and the intake port is exposed above sea level, air enters the inlet pipe. At this time, the copper alloy main impeller 2 cannot build up sufficient centrifugal force due to the intake of air, and the flow rate of the first delivery path drops sharply. However, the rubber auxiliary impeller 4 continues to rotate, and the volume change generated by its flexible blades and eccentric bushing 7 has a strong self-priming ability, which can force the gas-liquid mixture (a mixture of air and seawater) in the self-priming chamber to be drawn in and discharged. The specific process is as follows: When the rubber auxiliary impeller 4 rotates, the volume of the adjacent blade spacing area 4a increases at the inlet waist-shaped groove 3a, drawing in the gas-liquid mixture in the self-priming chamber; the volume decreases at the outlet waist-shaped groove 5a, forcibly discharging the gas-liquid mixture into the central cooler through the outlet pipe 13. At the same time, the low-pressure area at the rear cover plate of the copper alloy main impeller 2 continuously draws the gas-liquid mixture into the self-priming chamber through the balance hole 2a, forming a cycle. After several tens of seconds of circulating exhaust, the air in the inlet pipe is gradually exhausted, the seawater automatically fills the pump body, and the first delivery path returns to normal operation.

[0062] Performance after wear: After long-term use, the outer circle and end face of the rubber auxiliary impeller 4 will wear. Radial wear leads to a reduction in interference fit, and axial wear leads to a decrease in end face sealing pressure. When the wear reaches a certain level, the sealing performance of the self-priming chamber decreases, and the self-priming and exhaust function of the rubber auxiliary impeller 4 weakens or even fails. At this time, if hull tilting and air intake occur, the self-priming module may not be able to completely vent the air. However, the independent working capacity of the copper alloy main impeller 2 is not affected by the wear of the rubber auxiliary impeller 4. As long as there is seawater in the pump body (after normal start-up or after self-priming), the copper alloy main impeller 2 can still independently deliver the specified flow rate (e.g., 500L / min, head ≥9m) to meet the minimum cooling requirements of the engine. Therefore, the wear of the rubber auxiliary impeller 4 will not cause the cooling system to fail, but only reduces the self-priming backup function. Since hull tilting and air intake is an occasional condition, the actual working load of the rubber auxiliary impeller 4 is low, and its replacement cycle is much longer than that of a conventional flexible impeller pump (500 hours). When replacing, simply loosen the fastening bolt 9, remove the pump cover 6, and the rubber impeller 4 can be taken out for replacement. The operation is simple.

[0063] The self-priming centrifugal seawater pump assembly provided in this embodiment has a compact structure and can be directly installed at the engine crankshaft output end without the need for an additional large-capacity liquid storage chamber and gas-liquid separation chamber. Its dual-path parallel operating mode ensures reliable self-priming and guarantees the main function; wear of the rubber auxiliary impeller does not affect engine cooling, resulting in low maintenance costs. It is particularly suitable for marine cooling systems and can also be used in other industrial pumping applications requiring self-priming functionality.

[0064] Example 2

[0065] This embodiment is basically the same as Embodiment 1, except for the shape and number of blades in the rubber auxiliary impeller 4. In this embodiment, the rubber auxiliary impeller 4 includes 11 flexible blades, which extend outward from the central hub in a star shape. The blade cross-section is trapezoidal, thicker at the root and thinner at the tip to increase root strength. The blades radially engage with the eccentric inner hole of the bushing 7, with an eccentricity of 2mm and an interference fit of 0.4mm. The blade deformation of the rubber auxiliary impeller 4 in this embodiment is designed to be small to meet the low-frequency operating requirements of its use as a backup self-priming module, further extending its service life.

[0066] Example 3

[0067] This embodiment is basically the same as Embodiment 1, except for the setting of the opening pressure of the outlet check valve 8. In this embodiment, the outlet check valve 8 is a rubber-structured check valve, which can open in one direction as long as there is a pressure difference on both sides.

[0068] Example 4

[0069] This embodiment is basically the same as Embodiment 1, except for the anti-rotation structure. In this embodiment, there are four limiting pins 10, arranged at intervals along the circumference to provide a more reliable anti-rotation effect. The outer circle of the first section of the limiting pin has a threaded structure and connects to the threaded hole of the pump cover 6. The outer circle of the second section has a smooth rod structure and is inserted into the corresponding holes of the outlet distribution plate 5, bushing 7, and inlet distribution plate 3 from top to bottom.

[0070] Example 5

[0071] This embodiment is basically the same as Embodiment 1, except for the number and diameter of the balance holes 8 in the copper alloy main impeller 2. Based on the pump flow rate (473 L / min) and the sealing ring gap area, the number of balance holes 8 in this embodiment is 4, with a diameter of 12 mm and a total area of ​​452 mm², which is approximately 6.8 times the sealing ring gap area (66.7 mm²), in order to provide better self-priming circulation flow.

[0072] To facilitate understanding by those skilled in the art of the improvements made by the invention over the prior art, some of the accompanying drawings and descriptions have been simplified. The above embodiments are preferred implementations of the invention. In addition, the invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the technical solution are within the scope of protection of the invention.

Claims

1. A self-priming centrifugal seawater pump, comprising a pump body (1), a pump cover (6), and a pump shaft (12), wherein the pump body (1) is provided with an inlet and an outlet, characterized in that: A copper alloy main impeller (2) and a rubber auxiliary impeller (4) are mounted on the pump shaft (12). An inlet distribution plate (3) is mounted on one side of the rubber auxiliary impeller (4) near the copper alloy main impeller (2), and an outlet distribution plate (5) is mounted on the other side. An annular bushing (7) is fitted around the outer circumference of the rubber auxiliary impeller (4). The inner hole of the rubber auxiliary impeller (4) and the bushing (7) are eccentrically fitted. This eccentric fit causes the inner hole of the rubber auxiliary impeller (4) to deform and interfere with the inner hole of the bushing (7) to achieve radial sealing. The inlet distribution plate (3), the rubber auxiliary impeller (4), and the outlet distribution plate (5) are tightly fitted in the axial direction. The inlet distribution plate (3) and the outlet distribution plate (5) press the two end faces of the rubber auxiliary impeller (4) to achieve axial sealing. The rear cover plate of the copper alloy main impeller (2) is provided with a balance hole (2a). The inlet distribution plate (3) is provided with an inlet waist-shaped groove (3a), the outlet distribution plate (5) is provided with an outlet waist-shaped groove (5a), the pump cover (6) is provided with a pump cover (6) middle hole, and the pump cover (6) middle hole is connected to an outlet pipe (8a) including an outlet check valve (8); the balance hole (2a), the inlet waist-shaped groove (3a), the adjacent blade spacing area (4a) of the rubber auxiliary impeller (4), the outlet waist-shaped groove (5a), the inner area of ​​the pump cover (6) and the outlet pipe (8a) are connected in sequence to form a self-priming chamber; seawater enters the pump body (1) from the inlet, and after being pressurized by the rotation of the copper alloy main impeller (2), most of it is discharged from the outlet, and the other part enters the self-priming chamber through the balance hole (2a) on the back cover plate of the copper alloy main impeller (2), and is then pressurized by the rotation of the rubber auxiliary impeller (4) and discharged from the outlet pipe (8a).

2. The self-priming centrifugal seawater pump according to claim 1, characterized in that: The inlet distribution plate (3), outlet distribution plate (5) and bushing (7) are provided with axial limiting holes. The upper end face of the pump cover (6) is screwed with a limiting pin (10). The limiting pin (10) is inserted into the limiting holes on the inlet distribution plate (3), bushing (7) and outlet distribution plate (5) in sequence.

3. The self-priming centrifugal seawater pump according to claim 1 or 2, characterized in that: The pump cover (6) is installed on the pump body (1) by fastening bolts (9). The inner side of the pump cover (6) is provided with an annular boss (6b), and the end face of the annular boss (6b) is in contact with the outer end face of the outlet distribution plate (5).

4. The self-priming centrifugal seawater pump according to claim 1 or 2, characterized in that: The outer circle of the bushing (7) is coaxial with the outer circle of the copper alloy main impeller (2).

5. The self-priming centrifugal seawater pump according to claim 1 or 2, characterized in that: The shaft hole of the rubber secondary impeller (4) is provided with a keyway (4b) for installing a semi-circular key (11), which is connected to the water pump shaft (12) to transmit torque; the shaft hole of the copper alloy main impeller (2) is interference-fitted with the water pump shaft (12).

6. The self-priming centrifugal seawater pump according to claim 1 or 2, characterized in that: The other end of the pump shaft is sequentially fitted with a water seal (13), an oil seal (14), a first deep groove ball bearing (15), a bearing positioning sleeve (16), a second deep groove ball bearing (17), and a bore elastic retaining ring (18) along the axial direction between it and the connecting body (19).

7. The self-priming centrifugal seawater pump according to claim 1 or 2, characterized in that: The rubber impeller (4) includes multiple flexible blades. The flexible blades extend outward from the central hub in a star-shaped or radial pattern. The blades radially engage with the eccentric inner hole of the bushing (7) to achieve radial sealing through blade deformation.

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