External high-temperature molten salt vertical double-suction pump

Abstract

The utility model relates to a kind of external high-temperature molten salt vertical double-suction pump, the double-suction pump includes: base, flush pipe, lower pump cover, pump body, double-suction impeller, upper pump cover, shaft seal component, motor support, pump shaft, bearing component, shaft sleeve, sliding bearing sleeve, sliding bearing, end cover etc., pump suction inlet and outlet are horizontal in and out, double-suction impeller is installed on pump shaft, shaft sleeve and guide bearing sleeve are located double-suction impeller upper and lower position respectively, double-suction impeller is positioned by shaft sleeve, guide bearing sleeve installation;Pump shaft, double-suction impeller, shaft sleeve, guide bearing sleeve jointly constitute the rotor component of pump;Bearing component and sliding bearing jointly constitute the support component of pump;Rolling bearing is installed in bearing component, and its axial and radial load generated by pump group is borne. The utility model avoids the deformation problem caused by insufficient pump rotor support stiffness under high-temperature working condition, effectively avoids the amplification effect of slight inclination or center deviation, thereby reduce the risk of abnormal wear and vibration.

Description

Technical Field

[0001] This utility model relates to a vertical double-suction pump, specifically an external high-temperature molten salt vertical double-suction pump that reduces shaft length, significantly lowers maintenance costs and risks, and effectively avoids cavitation. Background Technology

[0002] A high-temperature molten salt pump is a special industrial pump designed for conveying high-temperature, highly corrosive, and easily solidified molten salt media. It is the "heart" of systems such as concentrated solar power (CSP) and molten salt energy storage, responsible for the circulation and transport of molten salt. It typically needs to operate stably for extended periods in a high-temperature and highly corrosive environment of 400–600℃.

[0003] Due to its special operating conditions, involving high temperature and corrosive media, higher requirements are placed on the design, operation and maintenance of the pump.

[0004] Most existing high-temperature molten salt pumps are traditional long-shaft submersible pumps or traditional submersible suspension pumps, which are vertical immersion pumps and are usually top-suspended structures. Because the pump itself is heavy, the tank body cannot withstand the weight of the pump, so an additional steel structure or concrete platform needs to be designed to support the weight of the pump itself. Furthermore, special insulation design and thermal expansion compensation are required at the connection between the two. The investment in foundation construction is large, and the working environment is at a high altitude, which brings potential difficulties to operation and maintenance.

[0005] Due to its long cantilever structure design (shaft length typically ≥5 meters, ≥15 meters for large storage tanks), the impeller is located at the end of the long shaft, essentially functioning as a massive suspended rotor. This structure inherently suffers from poor rigidity during high-speed rotation. Any slight tilt or center misalignment will be amplified during operation, leading to abnormal wear and vibration. This places high demands on installation accuracy, alignment between components, and the design of the foundation platform. Furthermore, it is sensitive to off-center loads; impeller imbalance and uneven media flow will amplify their effects, threatening shaft strength and bearing life.

[0006] The current installation method results in the main components of the high-temperature molten salt pump being located inside the molten salt tank. Furthermore, due to its long submerged depth, several intermediate and lower bearings are typically required to provide support and prevent excessive shaft oscillation. The bearings, submerged in high-temperature molten salt, are among the most vulnerable parts of the pump. Their maintenance and repair are extremely difficult; any maintenance requires lifting the entire pump out of the tank, a high-risk and costly process. Utility Model Content

[0007] To address the aforementioned problems, the main objective of this utility model is to provide an external high-temperature molten salt vertical double-suction pump that reduces shaft length, significantly lowers maintenance costs and risks, and effectively avoids cavitation.

[0008] This utility model solves the above-mentioned technical problems through the following technical solution: an external high-temperature molten salt vertical double-suction pump, the external high-temperature molten salt vertical double-suction pump comprising: a base, a flushing pipe, a lower pump cover, a pump body, a double-suction impeller, an upper pump cover, a shaft seal component, a motor bracket, a pump shaft, a bearing component, a shaft sleeve, a sliding bearing sleeve, a sliding bearing, and an end cover.

[0009] Both the pump inlet and outlet are horizontal. The pump body is fixedly installed on the base, located between the upper and lower pump covers. The motor is mounted on the motor bracket, which is fixedly installed above the pump body. One end of the flushing pipe is connected to the pump body outlet, and the other end is connected to the end cover. An air vent valve is designed on the flushing pipe. Molten salt provides lubrication for the sliding bearing through the flushing pipe and end cover under the pressure of the pump body outlet.

[0010] The double-suction impeller is mounted on the pump shaft. The shaft sleeve and guide bearing sleeve are located on the upper and lower positions of the double-suction impeller, respectively. The double-suction impeller is installed and positioned by the shaft sleeve and guide bearing sleeve. The pump shaft, double-suction impeller, shaft sleeve and guide bearing sleeve together form the rotor component of the pump. The bearing component and sliding bearing together form the support component of the pump. The bearing component is equipped with rolling bearings, which bear the axial and radial loads generated by the pump unit.

[0011] In a specific embodiment of this utility model, an air vent valve is provided on the flushing pipe.

[0012] In a specific embodiment of this utility model, the sliding bearing sleeve is fixed to the pump shaft by a round nut.

[0013] In a specific embodiment of this utility model, the bushing is fixed to the pump shaft by a second locking device.

[0014] In a specific embodiment of this utility model, the bushing is provided with a groove that effectively prevents high-temperature molten salt from entering the sealed cavity while ensuring the flow of external compressed gas.

[0015] In a specific embodiment of this utility model, the lower pump cover is designed with a salt discharge hole to facilitate the discharge of solidifiable molten salt during maintenance and downtime.

[0016] In a specific embodiment of this utility model, the bearing component is provided with a thin oil lubricating and cooling liquid in the rolling bearing.

[0017] In a specific embodiment of this utility model, the inner hole of the sliding bearing is designed with a lubrication guide groove, and the outer circle is designed with a guide hole and a liquid collection groove.

[0018] In a specific embodiment of this utility model, the bushing is fixed to the pump shaft by a first locking nut, which locks the bushing and thus locks the double-suction impeller.

[0019] In a specific embodiment of this utility model, sealing rings are provided on both the upper pump cover and the lower pump cover.

[0020] The positive and progressive effects of this utility model are as follows: The external high-temperature molten salt vertical double-suction pump provided by this utility model has the following advantages: This utility model replaces the existing long-shaft immersion pump with a vertical double-suction pump design with the same parameters. Its design features effectively avoid some inherent risks caused by the long shaft system of existing products, and solve the problems of high molten salt leakage risk and huge initial construction investment in existing designs; it also solves the problems of high investment and high risk in the operation and maintenance of existing equipment.

[0021] This invention replaces the existing long-shaft immersion pump with a vertical double-suction pump design with the same parameters, providing another feasible solution for existing solar thermal and energy storage molten salt pumping solutions. Attached Figure Description

[0022] Figure 1 A schematic diagram of the overall structure of this utility model.

[0023] The following are the names corresponding to the reference numerals in this utility model: In the diagram: 1. Base; 2. Flushing pipe; 3. Lower pump cover; 4. Pump body; 5. Double suction impeller; 6. Upper pump cover; 7. Shaft seal assembly; 8. Motor bracket; 9. Pump shaft; 10. Bearing assembly; 11. First locking nut; 12. Shaft sleeve; 13. Sealing ring; 14. Sliding bearing sleeve; 15. Sliding bearing; 16. Second locking device; 17. End cover. Detailed Implementation

[0024] The preferred embodiments of this utility model are given below with reference to the accompanying drawings to illustrate the technical solution of this utility model in detail.

[0025] Figure 1 A schematic diagram of the overall structure of this utility model is shown below. Figure 1 As shown: This utility model proposes an external high-temperature molten salt vertical double-suction pump, which includes: a base 1, a flushing pipe 2, a lower pump cover 3, a pump body 4, a double-suction impeller 5, an upper pump cover 6, a shaft seal component 7, a motor bracket 8, a pump shaft 9, a bearing component 10, a first locking nut 11, a shaft sleeve 12, a sealing ring 13, a sliding bearing sleeve 14, a sliding bearing 15, a second locking device 16, and an end cover 17.

[0026] Both the pump inlet and outlet are horizontal, and their directions can be changed according to different applications. The pump body 4 is fixedly mounted on the base 1, and is located between the upper pump cover 6 and the lower pump cover 3. Both the upper pump cover 6 and the lower pump cover 3 are equipped with sealing rings 13.

[0027] The motor is mounted on the motor bracket 8, which is fixedly mounted above the pump body 4. One end of the flushing pipe 2 is connected to the outlet of the pump body 4, and the other end is connected to the end cover 17. An air vent valve is designed on it. Molten salt provides lubrication for the sliding bearing through the flushing pipe 2 and the end cover 17 under the pressure of the outlet of the pump body 4.

[0028] The double-suction impeller 5 is mounted on the pump shaft 9. The shaft sleeve 12 and the guide bearing sleeve 14 are located above and below the double-suction impeller 5, respectively. The double-suction impeller 5 is installed and positioned by the shaft sleeve 12 and the guide bearing sleeve 14. The shaft sleeve 12 is fixed to the pump shaft 9 by a lock nut 11. The lock nut 11 locks the shaft sleeve 9, thereby locking the double-suction impeller 5.

[0029] The lower pump cover 3 is designed with a salt discharge hole to facilitate the discharge of solidifiable molten salt during maintenance and downtime, thus ensuring the operation of the pump unit system.

[0030] One end of the flushing pipe 2 is connected to the outlet of the pump body 4, and the other end is connected to the end cover 17. A drain valve is designed on it. Molten salt, under the pressure at the outlet of the pump body 4, provides lubrication to the sliding bearing through the flushing pipe 2 and the end cover 17. Its structure is simple, easy to use, and its operation and maintenance are convenient and reliable.

[0031] The double-suction impeller 5 is mounted on the pump shaft 9 and positioned via the shaft sleeve 12 and guide bearing sleeve 14. A flat key transmits the working torque to the double-suction impeller 5. The sliding bearing sleeve 14 is fixed to the pump shaft 9 by a round nut. The shaft sleeve 12 is fixed to the pump shaft 9 by a locking device 16. Its unique groove design effectively prevents high-temperature molten salt from entering the sealing cavity while ensuring the flow of external compressed gas. The high-pressure gas pushes the residual molten salt into the pump body suction port, thus preventing the accumulation of molten salt in the sealing cavity. Together, these two mechanisms provide a barrier for the main shaft seal of the unit.

[0032] The pump rotor assembly consists of the pump shaft 9, double-suction impeller 5, shaft sleeve 12, guide bearing sleeve 14, etc. The double-suction impeller 5 balances the axial force through its own design, improves the pump's net positive suction head (NPSH), and avoids the complex bearing system design of the original design.

[0033] The bearing assembly 10 and the sliding bearing 15 together form the pump's support components. The bearing assembly houses rolling bearings that bear the axial and radial loads generated by the pump unit and are lubricated and cooled by thin oil. It features a simple structure, easy machining, reliable operation, and convenient and simple maintenance.

[0034] The shaft seal component 7 adopts a combined sealing design, effectively solving the critical main shaft sealing problem of the molten salt pump. It also allows for remote monitoring and information-based surveillance, providing adaptive safety assurance for unit operation. Furthermore, its modular design allows for quick assembly and installation onto the main shaft system, greatly improving the convenience and timeliness of installation and maintenance.

[0035] The sliding bearing sleeve 14 and the sliding bearing 15 together form the sliding bearing component of the pump. The inner hole of the sliding bearing 15 is designed with a lubrication guide groove, and the outer circle is designed with a guide hole and a liquid collection groove. The high-pressure molten salt is lubricated by the flushing pipe 2 under the pressure of the pump body 4 outlet. The structure is simple, the maintenance and operation are highly predictable, and the operation, maintenance and repair are simple and convenient.

[0036] Most existing high-temperature molten salt pumps are traditional long-shaft submersible pumps or traditional submersible suspension pumps, which are vertical immersion pumps and are usually top-suspended structures. Because the pump itself is heavy, the tank body cannot withstand the weight of the pump, so an additional steel structure or concrete platform needs to be designed to support the weight of the pump itself. Furthermore, special insulation design and thermal expansion compensation are required at the connection between the two. The investment in foundation construction is large, and the working environment is at a high altitude, which brings potential difficulties to operation and maintenance.

[0037] This invention replaces the existing long-shaft immersion pump with a vertical double-suction pump design of the same parameters, which significantly reduces the pump's weight and length. It can be independently installed on the bottom platform of the tank, thus avoiding the infrastructure investment of steel structure and concrete platform. By designing an overflow pipe at the bottom of the tank, a loop can be formed with the pump. Furthermore, due to the height difference of the liquid level in the tank, a backflow effect can also be formed on the pump, thereby providing pressure to the pump inlet and effectively preventing cavitation.

[0038] Existing solutions employ a long cantilever structure design (shaft length typically ≥5 meters, ≥15 meters for large storage tanks), with the impeller located at the end of the long shaft, essentially functioning as a massive suspended rotor. This structure inherently suffers from poor rigidity during high-speed rotation. Any minute tilt or center misalignment will be amplified during operation, leading to abnormal wear and vibration. This places high demands on installation accuracy, alignment between components, and the design of the foundation platform. Furthermore, it is sensitive to off-center loads; impeller imbalance and uneven media flow will amplify their effects, threatening shaft strength and bearing life.

[0039] This utility model replaces the existing long-shaft immersion pump with a vertical double-suction pump design with the same parameters, which greatly reduces the shaft length. From its inherent design, it avoids the problems of poor rotor rigidity and high operation risk caused by long cantilever structure design. Moreover, its vertical design, compared with horizontal double-suction pump, fundamentally avoids the deformation problem caused by insufficient pump rotor support rigidity under high temperature conditions.

[0040] The current installation method results in the main components of the high-temperature molten salt pump being located inside the molten salt tank. Furthermore, due to its long submerged depth, several intermediate and lower bearings are typically required to provide support and prevent excessive shaft oscillation. The bearings, submerged in high-temperature molten salt, are among the most vulnerable parts of the pump. Their maintenance and repair are extremely difficult; any maintenance requires lifting the entire pump out of the tank, a high-risk and costly process.

[0041] This invention replaces the existing long-shaft submersible pump with a vertical double-suction pump design of equivalent parameters, significantly reducing the pump rotor length. Furthermore, the existing design allows for independent installation on the tank bottom platform, eliminating the need for steel structures and concrete platforms, thus significantly reducing the requirements for foundation platform design. This fundamentally lowers the difficulty of installation and commissioning, and improves the reliability of equipment installation. Because its design is located outside the tank, it fundamentally solves the complex pump hoisting work of the original design, significantly reducing maintenance costs and risks.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection of this utility model as defined by the appended claims and their equivalents.

Claims

1. An external high-temperature molten salt vertical double-suction pump, characterized in that: The external high-temperature molten salt vertical double-suction pump includes: a base, a flushing pipe, a lower pump cover, a pump body, a double-suction impeller, an upper pump cover, a shaft seal assembly, a motor bracket, a pump shaft, a bearing assembly, a shaft sleeve, a sliding bearing sleeve, a sliding bearing, and an end cover. Both the pump inlet and outlet are horizontal. The pump body is fixedly installed on the base and located between the upper and lower pump covers. The motor is mounted on the motor bracket, which is fixedly installed above the pump body. One end of the flushing pipe is connected to the pump body outlet, and the other end is connected to the end cover. An air vent valve is designed on the flushing pipe. Molten salt provides lubrication for the sliding bearing through the flushing pipe and end cover under the pressure of the pump body outlet. The double-suction impeller is mounted on the pump shaft. The shaft sleeve and guide bearing sleeve are located on the upper and lower positions of the double-suction impeller, respectively. The double-suction impeller is installed and positioned by the shaft sleeve and guide bearing sleeve. The pump shaft, double-suction impeller, shaft sleeve and guide bearing sleeve together form the rotor component of the pump. The bearing component and sliding bearing together form the support component of the pump. The bearing component is equipped with rolling bearings, which bear the axial and radial loads generated by the pump unit.

2. The external high-temperature molten salt vertical double-suction pump according to claim 1, characterized in that: An air vent valve is installed on the flushing pipe.

3. The external high temperature molten salt vertical double- suction pump according to claim 1, characterized in that: The sliding bearing sleeve is fixed to the pump shaft by a round nut.

4. The external high-temperature molten salt vertical double-suction pump according to claim 1, characterized in that: The bushing is fixed to the pump shaft by a second locking device.

5. The external high-temperature molten salt vertical double-suction pump according to claim 1, characterized in that: The bushing is equipped with grooves that effectively prevent high-temperature molten salt from entering the sealed cavity while ensuring the flow of external compressed gas.

6. The external high-temperature molten salt vertical double-suction pump according to claim 1, characterized in that: The lower pump cover is designed with a drain hole for easy maintenance and discharge of solidified molten salt during downtime.

7. The external high temperature molten salt vertical double- suction pump of claim 1, wherein: The rolling bearings in the bearing assembly are equipped with a thin oil lubricating and cooling liquid.

8. The external high temperature molten salt vertical double- suction pump of claim 1, wherein: The sliding bearing has a lubrication guide groove in the inner hole and a guide hole and a liquid collection groove in the outer circle.

9. The external high temperature molten salt vertical double- suction pump of claim 1, wherein: The shaft sleeve is fixed to the pump shaft by the first locking nut, which locks the shaft sleeve and thus locks the double-suction impeller.

10. The external high-temperature molten salt vertical double-suction pump according to claim 1, characterized in that: Both the upper and lower pump covers are equipped with sealing rings.

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