A marine large-flow single-stage double-suction vertical centrifugal pump

Abstract

The utility model provides a kind of marine high-flow single-stage double-suction vertical centrifugal pump, including vertical installation's double volute structure pump body, pump cover is arranged above pump body, and pump body lower end is arranged below, and pump suction inlet and pump discharge outlet are arranged on pump body, and impeller and pump shaft are installed between pump suction inlet and pump discharge outlet;The upper end journal of pump shaft is installed on pump cover by upper bearing assembly, and the lower end journal of pump shaft is installed in pump body lower end by lower bearing assembly, and upper bearing assembly includes upper bearing, upper bearing gland and upper bearing seat, and lower bearing assembly includes lower bearing and lower bearing gland;Further including mechanical seal component, and mechanical seal component includes machine seal gland and machine seal positioning sleeve;Further including connecting assembly and driving motor, and connecting assembly includes motor end coupling, intermediate coupling and pump end coupling, and the present application can effectively solve the problems of shafting stability, axial force balance, easy maintenance and anti-cavitation under the premise of ensuring the large flow of pump body.

Description

Technical Field

[0001] This utility model relates to the field of fluid transport machinery technology, specifically to a centrifugal pump, and more particularly to a marine high-flow single-stage double-suction vertical centrifugal pump. Background Technology

[0002] On ships, centrifugal pumps are the most widely used and numerous type of pump, primarily used in ballast water systems, cooling water systems, fire protection systems, and tank cleaning drainage systems. They are one of the key pieces of equipment on board, and their performance affects the ship's stability, operational efficiency, and even safety. With the increasing size of modern ships, higher demands are placed on the flow rate, reliability, and spatial layout of centrifugal pumps.

[0003] Traditional vertical centrifugal pumps, when pursuing high flow rates, typically employ large-diameter single-suction impellers or single-suction double-impeller designs. Large-diameter single-suction impeller pumps not only experience high axial forces and demanding bearing requirements, but also have limited efficiency improvements. Single-suction double-impeller pumps, on the other hand, result in long axial dimensions, complex structures, heavy pump bodies, high manufacturing costs, and inconvenient maintenance. Double-suction impellers can effectively balance axial forces and allow for higher flow rates and speeds, but traditional horizontal double-suction pumps, while offering high flow rates, occupy a large area, making them inconvenient for the compact layouts of ship engine rooms. Existing vertical centrifugal pumps often face the following technical challenges when used in high-flow-rate applications:

[0004] 1) Poor shaft stability: The pump shaft is long and is prone to vibration and deflection when running at high speed and under heavy load, which affects the mechanical seal and bearing life.

[0005] 2) Axial force balance problem: Theoretically, the axial force of the double suction impeller is self-balancing, but in actual operation, due to machining errors or flow field asymmetry, there is still residual axial force, which requires reliable bearings to bear.

[0006] 3) Inconvenient maintenance: The replacement of the lower bearing (guide bearing) of traditional vertical pumps is difficult, often requiring the entire rotor to be lifted out or even the pump body to be disassembled, resulting in a large workload and long maintenance time.

[0007] 4) Cavitation performance: Under high flow rate suction conditions, the requirements for the pump's cavitation performance are extremely high, which may be difficult to meet with traditional structural designs.

[0008] Therefore, there is an urgent need for a new type of vertical centrifugal pump that can solve the problems of shaft stability, axial force balance, easy maintenance and cavitation resistance while ensuring a large flow rate. Utility Model Content

[0009] This utility model aims to overcome the shortcomings of the existing technology and provide a marine high-flow single-stage double-suction vertical centrifugal pump with compact structure, large flow rate, stable and reliable operation, and easy maintenance. Specifically, it is a marine high-flow single-stage double-suction vertical centrifugal pump that is particularly suitable for the high-flow transportation needs of large ships.

[0010] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0011] A marine high-flow single-stage double-suction vertical centrifugal pump is characterized by: a pump body with a vertically installed double volute structure, a pump cover on the top of the pump body, a lower end of the pump body on the bottom, a pump inlet and a pump outlet on the pump body, an impeller and a pump shaft for driving the impeller to rotate installed between the pump inlet and the pump outlet, the impeller being a double-suction closed impeller, the double-suction closed impeller being circumferentially fixed and torque transmitted to the pump shaft by an impeller key, and being axially fixed by an impeller locking nut fastened to the pump shaft;

[0012] The centerlines of the pump inlet and the pump outlet are on a horizontal straight line and are located on both sides of the pump body. The pump inlet is divided into two independent chambers within the pump body, namely the upper suction chamber and the lower suction chamber, which correspond to the two suction inlets of the double-suction closed impeller.

[0013] The upper journal of the pump shaft is mounted on the pump cover via an upper bearing assembly, and the lower journal of the pump shaft is mounted on the lower end of the pump body via a lower bearing assembly. The upper bearing assembly includes an upper bearing cover, an upper bearing, and an upper bearing seat. The upper bearing seat is fixedly mounted on the pump cover, the upper bearing is mounted inside the upper bearing seat, and the upper bearing cover is mounted on the upper bearing seat and covers the upper bearing. The upper bearing is a pair of angular contact ball bearings mounted back-to-back with a bearing spacer between them. The upper journal of the pump shaft passes through the pump cover and is mounted inside the upper bearing, with its end passing through the upper bearing cover. The lower bearing assembly includes a lower bearing and a lower bearing cover. A lower bearing mounting hole is provided at the lower end of the pump body, and the lower bearing is mounted inside the lower bearing mounting hole. The lower bearing cover is mounted on the lower bearing mounting hole. The lower bearing is a sliding bearing, and the lower journal of the pump shaft is mounted in the lower bearing. The lower journal of the pump shaft and the lower bearing are clearance-fitted and slidably connected.

[0014] It also includes a mechanical seal component, which includes a mechanical seal gland and a mechanical seal positioning sleeve. The mechanical seal gland is installed between the pump shaft and the pump cover, and the mechanical seal positioning sleeve is fitted on the pump shaft and has an interference fit with the upper end journal of the pump shaft.

[0015] It also includes a connecting assembly and a drive motor. The connecting assembly includes a motor end coupling, an intermediate coupling, and a pump end coupling. The motor end coupling is mounted on the output shaft of the drive motor, and the pump end coupling is mounted on the upper journal end of the pump shaft. The pump end coupling and the motor end coupling are connected through the intermediate coupling. The drive motor is vertically fixed above the pump body.

[0016] Furthermore, the upper bearing assembly also includes an upper bearing locking nut, which locks the inner ring of the upper bearing onto the upper journal of the pump shaft.

[0017] Furthermore, the lower bearing assembly also includes a first O-ring, which is installed between the lower bearing cap and the lower bearing mounting hole.

[0018] Furthermore: the bottom of the pump body and the lower end of the pump body are integrally cast.

[0019] Furthermore, it also includes a motor bracket, which is sleeved on the outside of the connecting assembly and fixed to the pump body, and the drive motor is vertically fixed to the motor bracket by bolts.

[0020] Furthermore: the pump cover is provided with a groove, the upper bearing seat is installed above the groove, the bottom of the groove is provided with a through hole for the pump shaft to pass through, the through hole and the pump shaft are mechanically sealed, a water baffle ring is provided in the groove, a skeleton oil seal is provided between the water baffle ring and the upper bearing seat, a second O-ring and a third O-ring are respectively provided between the pump body and the pump cover, and a fourth O-ring is provided between the skeleton oil seal and the bottom wall of the groove.

[0021] Furthermore, the upper bearing end cap is provided with a grease fitting.

[0022] Furthermore, an impeller gasket is installed between the double-suction closed impeller and the pump shaft.

[0023] In the above structure: the pump body in this application is a vertically installed double volute structure, and its bottom and the lower end of the pump body are integrally cast, which has good structural rigidity and can effectively suppress vibration.

[0024] A horizontal pump inlet is provided on one side of the middle part of the pump body. The pump inlet is divided into two independent and symmetrical suction chambers in the pump body, namely the upper suction chamber and the lower suction chamber. These two suction chambers correspond precisely to the upper and lower suction ports on the upper and lower sides of the double-suction closed impeller. A horizontal pump outlet is provided on the other side of the middle part of the pump body. The center lines of the pump inlet and pump outlet flanges are on a horizontal straight line.

[0025] The pump shaft is a vertical shaft. The uppermost journal of the pump shaft is mounted on the upper bearing assembly set on the pump cover, and the lowermost journal of the pump shaft is mounted on the lower bearing assembly set at the lower end of the pump body. It passes through the impeller working chamber, pump cover, mechanical seal cover, upper bearing seat, upper bearing and upper bearing cover on the pump body.

[0026] The upper bearing assembly includes an upper bearing cover, an upper bearing, and an upper bearing housing. The upper bearing is located on the upper part of the pump shaft and is installed in a cavity formed by the upper bearing housing and the upper bearing cover. Crucially, the upper bearing uses a pair of back-to-back angular contact ball bearings with a bearing spacer between them. These angular contact ball bearings can withstand both radial forces and bidirectional residual axial forces, ensuring precise positioning and stable operation of the shaft system. The upper bearing lock nut locks the inner ring of the upper bearing onto the pump shaft. The weight of the pump's rotating body is transferred from the upper bearing to the upper bearing housing, meaning the drive motor does not need to bear the weight of the pump's rotating body, thus extending the service life of the drive motor's bearings. The lower bearing assembly includes a lower bearing and a lower bearing cover. The lower bearing is a sliding bearing (copper sleeve) and is installed in a lower bearing mounting hole at the lower end of the pump body. It is pressed and fixed to the pump body by the lower bearing cover, which is fixed from below with bolts. The lowermost end of the pump shaft extends into the lower bearing hole. The two are clearance fit and sliding connection. The lower bearing mainly acts as a guide bearing for the pump shaft, providing radial auxiliary support for the pump shaft and controlling the radial vibration of the pump shaft.

[0027] The impeller is a double-suction closed impeller, which is circumferentially fixed and torque transmitted to the pump shaft through the impeller key. It is axially fixed by two impeller locking nuts fastened to the middle and lower section of the pump shaft, located between the upper suction chamber and the lower suction chamber. The impeller locking nuts are located below the double-suction closed impeller.

[0028] The mechanical seal component is installed in the central shaft hole of the pump cover and is secured by bolts to the mechanical seal gland. A special mechanical seal positioning sleeve is provided, which is fitted onto the pump shaft and has an interference fit with the pump shaft journal. This is used to provide precise axial support and positioning for the mechanical seal, preventing it from failing due to shaft deflection or vibration.

[0029] The drive motor is vertically mounted on the upper end of the pump body. Its output shaft is connected to the upper end of the pump shaft through a motor end coupling, an intermediate coupling, and a pump end coupling, driving the pump shaft and impeller to rotate synchronously.

[0030] During operation, the drive motor starts and drives the pump shaft to rotate at high speed through the motor end coupling, intermediate coupling and pump end coupling. The pump shaft drives the double-suction closed impeller to rotate at high speed. Liquid enters from the pump suction port, is divided into the upper suction chamber and the lower suction chamber, and is sucked in from the upper and lower suction ports of the double-suction closed impeller. After being pressurized, it flows into the double volute flow channel and is finally discharged from the pump discharge port.

[0031] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0032] 1. Extremely high operational stability: Utilizing a hybrid support system of "angular contact ball bearings (upper bearing) + sliding bearings (lower bearing)". The upper bearing, with its angular contact ball bearings, can simultaneously withstand radial and bidirectional axial forces, greatly enhancing the rigidity and stability of long shaft systems and effectively reducing operational vibration. The lower bearing uses copper-sleeved sliding bearings with excellent wear resistance and vibration absorption.

[0033] 2. Extremely long service life of drive motor: The weight of rotating parts such as pump shaft and impeller is borne by the upper bearing, not by the drive motor, which greatly extends the maintenance interval of drive motor bearings and the service life of drive motor.

[0034] 3. Excellent anti-cavitation performance and high flow rate: The single-stage double-suction impeller structure not only balances most of the axial force, but more importantly, its inlet flow channel area is doubled and the flow velocity is low, which fundamentally reduces the required net positive suction head (NPSHr) of the pump, making it very suitable for ship operating conditions with high flow rate suction.

[0035] 4. Double volute pump body design: The pump body adopts a double volute structure, which can effectively balance the radial force generated by the impeller during operation, further reduce bearing load and shaft deflection, and improve the pump's service life and efficiency.

[0036] 5. Excellent Maintenance Convenience: This utility model offers significant maintenance advantages. Both the motor and upper bearing assembly are located above the pump body. After removing the coupling bolts and the nuts securing the motor bracket to the pump body, the drive motor and motor bracket can be lifted out as a whole, allowing for inspection or replacement of the upper bearing assembly and mechanical seal. The lower bearing (copper sleeve) can also be replaced separately by removing the lower bearing cover, significantly reducing maintenance workload and time, eliminating the need to disassemble the entire pump body and piping.

[0037] 6. Compact structure and space-saving: The vertical double-suction structure greatly reduces the footprint of the pump unit, and the short span between the two angular contact ball bearings in the upper bearing significantly reduces the overall height of the pump, making it ideal for space-constrained ship engine room layouts. The pump body and base are integrally cast, enhancing overall rigidity and simplifying installation.

[0038] 7. Strong adaptability to marine applications: The structural design takes into account the special working conditions of the ship's environment, such as vibration and swaying, and has good overall rigidity and reliable operation. Attached Figure Description

[0039] Figure 1 A schematic diagram of a marine single-stage double-suction vertical centrifugal pump;

[0040] Figure 2 This is a sectional view of the pump body;

[0041] Figure 3 This is a front view of the pump;

[0042] Figure 4 This is a side view of the pump.

[0043] List of reference numerals in the attached diagram:

[0044] 1. Drive motor; 2. Motor end coupling; 3. Intermediate coupling; 4. Pump end coupling; 5. Upper bearing cover; 6. Upper bearing; 7. Upper bearing housing; 8. Mechanical seal cover; 9. Pump cover; 10. Pump shaft; 11. Impeller; 12. Sealing ring; 13. Pump body; 130. Lower end of pump body; 131. Pump inlet; 1311. Upper suction chamber; 1312. Lower suction chamber; 132. Pump outlet; 133. Lower bearing housing 14. Mounting hole; 15. Lower bearing cover; 16. First O-ring; 17. Lower bearing; 18. Impeller lock nut; 19. Impeller key; 20. Second O-ring; 21. Impeller gasket; 22. Mechanical seal positioning sleeve; 23. Third O-ring; 24. Mechanical seal; 25. Fourth O-ring; 26. Water baffle; 27. Oil seal; 28. Bearing spacer; 29. ​​Grease fitting; 30. Upper bearing lock nut; 21. Motor bracket. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0046] like Figures 1-4 As shown, this utility model proposes a marine high-flow single-stage double-suction vertical centrifugal pump, including a pump body 13 with a vertically installed double volute structure. A pump cover 9 is provided on the top of the pump body 13, and a lower end 130 of the pump body is provided on the bottom. The pump body 13 is provided with a pump inlet 131 and a pump outlet 132. An impeller 11 and a pump shaft 10 for driving the impeller 11 to rotate are installed between the pump inlet 131 and the pump outlet 132. The impeller 11 is a double-suction closed impeller. The double-suction closed impeller is circumferentially fixed and torque transmitted to the pump shaft 10 through an impeller key 18. It is axially fixed by an impeller locking nut 17 fastened to the pump shaft 10.

[0047] The centerlines of the pump inlet 131 and the pump outlet 132 are on a horizontal straight line and are located on both sides of the pump body 13. The pump inlet 131 is divided into two independent chambers inside the pump body 13, namely the upper suction chamber 1311 and the lower suction chamber 1312. The upper suction chamber 1311 and the lower suction chamber 1312 correspond to the two suction ports on both sides of the double-suction closed impeller.

[0048] The upper journal of the pump shaft 10 is mounted on the pump cover 9 via an upper bearing assembly, and the lower journal of the pump shaft 10 is mounted on the lower end 130 of the pump body via a lower bearing assembly. The upper bearing assembly includes an upper bearing cap 5, an upper bearing 6, and an upper bearing seat 7. The upper bearing seat 7 is fixedly mounted on the pump cover 9, and the upper bearing 6 is mounted inside the upper bearing seat 7. The upper bearing cap 5 is mounted on the upper bearing seat 7 and covers the upper bearing 6. The upper bearing 6 is a pair of angular contact ball bearings mounted back-to-back, with a bearing spacer 27 installed between them. The upper journal passes through the pump cover 9 and is installed in the upper bearing 6, and its end passes through the upper bearing cover 5. The lower bearing assembly includes a lower bearing 16 and a lower bearing cover 14. The lower end 130 of the pump body has a lower bearing mounting hole 133. The lower bearing 16 is installed in the lower bearing mounting hole 133, and the lower bearing cover 14 is installed on the lower bearing mounting hole 133. The lower bearing 16 is a sliding bearing. The lower journal of the pump shaft 10 is installed in the lower bearing 16. The lower journal of the pump shaft 10 and the lower bearing 16 are clearance fit and sliding connection.

[0049] It also includes a mechanical seal component, which includes a mechanical seal gland 8 and a mechanical seal positioning sleeve 21. The mechanical seal gland 8 is installed between the pump shaft 10 and the pump cover 9, and the mechanical seal positioning sleeve 21 is fitted on the pump shaft 10 and has an interference fit with the upper journal of the pump shaft 10.

[0050] The system also includes a connecting assembly and a drive motor 1. The connecting assembly includes a motor end coupling 2, an intermediate coupling 3, and a pump end coupling 4. The motor end coupling 2 is mounted on the output shaft of the drive motor 1, and the pump end coupling 4 is mounted on the upper journal end of the pump shaft 10. The pump end coupling 4 and the motor end coupling 2 are connected via the intermediate coupling 3. The drive motor 1 is vertically fixed above the pump body 13. The upper bearing assembly also includes an upper bearing locking nut 29, which locks the inner ring of the upper bearing 6 onto the upper journal of the pump shaft 10. The lower bearing assembly also includes a first O-ring 15, which is installed between the lower bearing cap 14 and the lower bearing mounting hole 133. The bottom of the pump body 13 and the lower end 130 of the pump body are integrally cast. The system also includes a motor bracket 30, which is sleeved on the outside of the connecting assembly and fixed to the pump body 13. The drive motor 1 is vertically fixed to the motor bracket 30 by bolts. The pump cover 9 has a groove, and the upper bearing seat 7 is installed above the groove. A through hole for the pump shaft 10 to pass through is provided at the bottom of the groove. A mechanical seal 23 is located between the through hole and the pump shaft 10. A water-retaining ring 25 is provided inside the groove. A skeleton oil seal 26 is provided between the water-retaining ring 25 and the upper bearing seat 7. A second O-ring 19 and a third O-ring 22 are respectively provided between the pump body 13 and the pump cover 9. A fourth O-ring 24 is provided between the skeleton oil seal 26 and the bottom wall of the groove. A grease fitting 28 is provided on the end cap of the upper bearing 6. An impeller gasket 20 is installed between the double-suction closed impeller and the pump shaft 10.

[0051] The pump body 13 in this application is a vertically installed double volute structure. Its bottom and the lower end 130 of the pump body are integrally cast, which has good structural rigidity and can effectively suppress vibration.

[0052] A horizontal pump inlet 131 is provided on one side of the middle part of the pump body 13. The pump inlet 131 divides the flow inside the pump body 13 to form two independent and symmetrical suction chambers, namely the upper suction chamber 1311 and the lower suction chamber 1312. These two suction chambers correspond precisely to the upper and lower suction ports on the upper and lower sides of the double-suction closed impeller. A horizontal pump outlet 132 is provided on the other side of the middle part of the pump body 13. The center lines of the flanges of the pump inlet 131 and the pump outlet 132 are on a horizontal straight line.

[0053] The pump shaft 10 is a vertical shaft. The uppermost journal of the pump shaft 10 is mounted on the upper bearing assembly set on the pump cover 9, and the lowermost journal of the pump shaft 10 is mounted on the lower bearing assembly set on the lower end 130 of the pump body. It passes through the impeller 11 working chamber, pump cover 9, mechanical seal cover 8, upper bearing seat 7, upper bearing 6 and upper bearing cover 5 on the pump body 13.

[0054] The upper bearing assembly includes an upper bearing cap 5, an upper bearing 6, and an upper bearing housing 7. The upper bearing 6 is located on the upper part of the pump shaft 10 and is installed in the cavity formed by the upper bearing housing 7 and the upper bearing cap 5. Crucially, the upper bearing 6 adopts a pair of back-to-back angular contact ball bearings, with a bearing spacer 27 between the pair of angular contact ball bearings. These angular contact ball bearings can withstand both radial force and bidirectional residual axial force, ensuring the precise positioning and stable operation of the shaft system. The upper bearing locking nut 29 locks the inner ring of the upper bearing 6 onto the pump shaft 10. The weight of the pump rotating body is transferred from the upper bearing 6 to the upper bearing housing 7, meaning that the drive motor 1 does not need to bear the weight of the pump rotating body, thereby extending the bearing service life of the drive motor 1. The lower bearing assembly includes a lower bearing 16 and a lower bearing cover 14. The lower bearing 16 is a sliding bearing (copper sleeve) and is installed in the lower bearing mounting hole 133 opened at the lower end 130 of the pump body. It is pressed and fixed to the pump body 13 by the lower bearing cover 14, which is fixed from below with bolts. The lowermost end of the pump shaft 10 extends into the hole of the lower bearing 16. The two are clearance fit and sliding connection. The lower bearing 16 mainly acts as a guide bearing for the pump shaft 10, providing radial auxiliary support for the pump shaft 10 and controlling the radial vibration of the pump shaft 10.

[0055] Impeller 11 is a double-suction closed impeller. It is circumferentially fixed and torque transmitted to pump shaft 10 by impeller key 18. It is axially fixed by two impeller locking nuts 17 in the middle and lower section of pump shaft 10. It is located between upper suction chamber 1311 and lower suction chamber 1312. The impeller locking nuts 17 are located below the double-suction closed impeller.

[0056] The mechanical seal component is installed at the central shaft hole of the pump cover 9 and is secured by bolts to the mechanical seal gland 8. A special mechanical seal positioning sleeve 21 is provided, which is fitted onto the pump shaft 10 and has an interference fit with the journal of the pump shaft 10. This is used to provide precise axial support and positioning for the mechanical seal 23 and prevent it from failing due to shaft deflection or vibration.

[0057] The drive motor 1 is vertically mounted on the upper end of the pump body 13. Its output shaft is connected to the upper end of the pump shaft 10 through the motor end coupling 2, the intermediate coupling 3 and the pump end coupling 4, driving the pump shaft 10 and the impeller 11 to rotate synchronously.

[0058] During operation, the drive motor 1 starts and drives the pump shaft 10 to rotate at high speed through the motor end coupling 2, the intermediate coupling 3 and the pump end coupling 4. The pump shaft 10 drives the double-suction closed impeller to rotate at high speed. The liquid enters from the pump suction port 131, is divided into the upper suction chamber 1311 and the lower suction chamber 1312, and is sucked in from the upper and lower suction ports of the double-suction closed impeller. After being pressurized, it flows into the double volute flow channel and is finally discharged from the pump discharge port 132.

[0059] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any modifications or equivalent changes made based on the technical essence of the present utility model shall still fall within the scope of protection claimed by the present utility model.

Claims

1. A marine high-flow single-stage double-suction vertical centrifugal pump, characterized in that: The pump body (13) includes a vertically mounted double volute structure. A pump cover (9) is provided on the top of the pump body (13), and a pump body lower end (130) is provided on the bottom. A pump inlet (131) and a pump outlet (132) are provided on the pump body (13). An impeller (11) and a pump shaft (10) for driving the impeller (11) to rotate are installed between the pump inlet (131) and the pump outlet (132). The impeller (11) is a double-suction closed impeller. The double-suction closed impeller is circumferentially fixed and torque is transmitted to the pump shaft (10) through an impeller key (18). It is axially fixed by an impeller locking nut (17) fastened to the pump shaft (10). The centerlines of the pump inlet (131) and the pump outlet (132) are on a horizontal straight line and are located on both sides of the pump body (13). The pump inlet (131) splits the flow inside the pump body (13) to form two independent chambers, namely the upper suction chamber (1311) and the lower suction chamber (1312). The upper suction chamber (1311) and the lower suction chamber (1312) correspond to the two suction ports on both sides of the double-suction closed impeller. The upper journal of the pump shaft (10) is mounted on the pump cover (9) via an upper bearing assembly, and the lower journal of the pump shaft (10) is mounted on the lower end (130) of the pump body via a lower bearing assembly. The upper bearing assembly includes an upper bearing cap (5), an upper bearing (6), and an upper bearing seat (7). The upper bearing seat (7) is fixedly mounted on the pump cover (9), and the upper bearing (6) is mounted inside the upper bearing seat (7). The upper bearing cap (5) is mounted on the upper bearing seat (7) and covers the upper bearing (6). The upper bearing (6) is a pair of angular contact ball bearings mounted back-to-back, with a bearing spacer (27) installed between them. The pump shaft (10) The upper end journal passes through the pump cover (9) and is installed in the upper bearing (6), and its end passes through the upper bearing cover (5). The lower bearing assembly includes a lower bearing (16) and a lower bearing cover (14). The lower end (130) of the pump body has a lower bearing mounting hole (133). The lower bearing (16) is installed in the lower bearing mounting hole (133). The lower bearing cover (14) is installed on the lower bearing mounting hole (133). The lower bearing (16) is a sliding bearing. The lower end journal of the pump shaft (10) is installed in the lower bearing (16). The lower end journal of the pump shaft (10) and the lower bearing (16) are clearance fit and sliding connection. It also includes a mechanical seal component, which includes a mechanical seal (23), a mechanical seal gland (8) and a mechanical seal positioning sleeve (21). The mechanical seal gland (8) is installed between the pump shaft (10) and the pump cover (9). The mechanical seal positioning sleeve (21) is fitted on the pump shaft (10) and has an interference fit with the upper journal of the pump shaft (10). It also includes a connecting assembly and a drive motor (1). The connecting assembly includes a motor end coupling (2), an intermediate coupling (3), and a pump end coupling (4). The motor end coupling (2) is mounted on the output shaft of the drive motor (1). The pump end coupling (4) is mounted on the upper journal end of the pump shaft (10). The pump end coupling (4) is connected to the motor end coupling (2) through the intermediate coupling (3). The drive motor (1) is vertically fixed above the pump body (13).

2. The marine high-flow single-stage double-suction vertical centrifugal pump according to claim 1, characterized in that: The upper bearing assembly also includes an upper bearing locking nut (29), which locks the inner ring of the upper bearing (6) onto the upper journal of the pump shaft (10).

3. A marine high-flow single-stage double-suction vertical centrifugal pump according to claim 1, characterized in that: The lower bearing assembly also includes a first O-ring (15), which is installed between the lower bearing cap (14) and the lower bearing mounting hole (133).

4. A marine high-flow single-stage double-suction vertical centrifugal pump according to claim 1, characterized in that: The bottom of the pump body (13) and the lower end (130) of the pump body are integrally cast.

5. A marine high-flow single-stage double-suction vertical centrifugal pump according to claim 1, characterized in that: It also includes a motor bracket (30), which is sleeved on the outside of the connecting assembly and fixed on the pump body (13), and the drive motor (1) is vertically fixed on the motor bracket (30) by bolts.

6. A marine high-flow single-stage double-suction vertical centrifugal pump according to claim 1, characterized in that: The pump cover (9) is provided with a groove, the upper bearing seat (7) is installed above the groove, the bottom of the groove is provided with a through hole for the pump shaft (10) to pass through, the through hole and the pump shaft (10) are mechanically sealed (23), a water baffle (25) is provided in the groove, a skeleton oil seal (26) is provided between the water baffle (25) and the upper bearing seat (7), a second O-ring (19) and a third O-ring (22) are respectively provided between the pump body (13) and the pump cover (9), and a fourth O-ring (24) is provided between the skeleton oil seal (26) and the bottom wall of the groove.

7. A marine high-flow single-stage double-suction vertical centrifugal pump according to claim 1, characterized in that: The upper bearing (6) end cap is provided with a grease nipple (28).

8. A marine high-flow single-stage double-suction vertical centrifugal pump according to claim 1, characterized in that: An impeller gasket (20) is installed between the double-suction closed impeller and the pump shaft (10).

Images