Submerged high temperature pump

Abstract

This solution discloses a submersible high-temperature pump, including a main shaft driven by a motor, an axial thrust magnetic bearing mounted on the motor end of the main shaft, and an impeller end of the main shaft submerged in a high-temperature medium. It also includes a pump casing and a sliding bearing. The main shaft extends into the pump casing, and the sliding bearing is installed between the main shaft and the pump casing. The sliding bearing is located on the main shaft near the impeller. A radial magnetic bearing is installed axially adjacent to the axial thrust magnetic bearing. The advantages of this solution are: based on the operating environment and structural characteristics of the submersible high-temperature pump, it innovatively adopts a hybrid approach using magnetic and sliding bearings, leveraging the advantages of various bearing types, balancing equipment reliability and lifespan, reducing equipment complexity, simplifying the structure, lowering costs, and bringing significant economic benefits while reducing manufacturing and maintenance costs.

Description

Technical Field

[0001] This utility model relates to the field of high-temperature pumps, specifically a submersible high-temperature pump. Background Technology

[0002] High-temperature pumps are pumps specifically designed for conveying high-temperature media. In order to operate normally at high temperatures and be compatible with the system immersion depth requirements, the rotors of submerged high-temperature pump sets (conveying media temperature ≥400℃), such as liquid metal pumps and molten salt pumps, often adopt a long cantilever structure, with the motor located at the top and the impeller for conveying the media located at the bottom.

[0003] Traditional pump units often use sliding or rolling bearings, which have limitations in service life. Firstly, if rolling bearings are used, they are typically positioned above the liquid surface, resulting in excessively long cantilever arms, severe eccentricity and wobble on the long shaft, and harsh operating conditions for the bearings. This leads to accelerated aging and failure of the rolling bearings, causing mechanical wear. Secondly, to avoid excessive cantilever length and improve rotor stability, two media-lubricated sliding bearings can be used, forming two radial support points. However, to ensure sufficient support rigidity, the friction pair clearance of sliding bearings is generally small. Consequently, such pump units often experience lubrication failure or shaft jamming due to impurities or properties in the medium, resulting in a short service life.

[0004] Chinese patent document CN119878538A, published on April 25, 2025, discloses an expandable multi-stage magnetic levitation molten salt pump. This pump includes three sequentially connected pump stages (first, second, and third) between its suction and pressure ports. A radial magnetic levitation bearing assembly is positioned between the first and second pump stages to provide rotational support for the rotor. An axial magnetic levitation bearing is positioned between the second and third pump stages to provide axial support for the rotor. This invention separates the axial and radial magnetic levitation bearings, making the axial bearing easier to inspect and repair, reducing maintenance costs, and improving the pump's long-term reliability. The unique structural interaction between the different pump stages, guide vanes, and the flow channel formed by the magnetic levitation bearing housing effectively improves hydraulic efficiency and unit operational stability.

[0005] Chinese patent document CN117748819A, published on March 22, 2024, discloses a two-point magnetic levitation pump assembly with a cantilevered impeller, comprising a shielded motor, axial magnetic bearings, a pump body, protective bearings, and a sensor system. This assembly features a coaxial design between the motor shaft and the impeller shaft, and suspends the rotor as a whole via magnetic bearings, achieving contactless rotor support to suppress mechanical vibrations generated by the rotor-bearing system. Simultaneously, controllable electromagnetic force is applied using electromagnetic bearings to actively cancel out major mechanical vibrations. Furthermore, suspending the rotor effectively reduces pump bearing wear and improves the operational reliability of the device.

[0006] Chinese patent document CN117748818A, published on March 22, 2024, discloses a topology of a multi-stage impeller magnetic levitation pump set with two suspension points and three protection points. This structure comprises a motor 1, a multi-stage pump 2, an axial magnetic bearing 3, a radial magnetic bearing, a protection bearing, a rotating shaft 9, and a filter 10. This structure eliminates components such as mechanical seals and couplings found in traditional pump sets, integrating the motor shaft and pump shaft. It employs two suspension points and three protection points to levitate and protect the rotor as a whole, achieving contactless rotor support. Based on the compact structure of the multi-stage impeller pump set, the axial length of the pump set is effectively reduced, significantly improving the overall integration of the device.

[0007] Similar to existing magnetic levitation pumps, these typically include two or more radial electromagnetic bearings and one thrust electromagnetic bearing. Because the rotor is supported by magnetic bearings, non-contact support avoids mechanical lubrication wear, extending the equipment's service life. However, electromagnetic bearings are mechatronic devices, introducing numerous electrical components and resulting in complex hardware and control systems. They also exhibit high failure rates and low reliability, especially in high-temperature and complex environments, failing to meet the reliability requirements of nuclear power and special equipment. Summary of the Invention

[0008] To address the above issues, this invention provides a submersible high-temperature pump that uses a combination of various bearings to balance equipment reliability and lifespan requirements.

[0009] To achieve the purpose of this invention, the present invention adopts the following technical solution: A submersible high-temperature pump, comprising a main shaft driven to rotate by a motor, an axial thrust magnetic bearing mounted on the motor end of the main shaft, and an impeller end of the main shaft submerged in a high-temperature medium. It also includes the pump housing and sliding bearings; The main shaft extends into the pump casing, and a sliding bearing is installed between the main shaft and the pump casing.

[0010] Preferably, the sliding bearing is installed on the main shaft near the impeller.

[0011] Preferably, a radial magnetic bearing is installed on the axial side of the axial thrust magnetic bearing.

[0012] As a preferred embodiment, the bearing clearance of the radial magnetic bearing is G1, and the bearing clearance of the sliding bearing (8) is G2, so that G2 < G1.

[0013] As a preferred option, with the radius of the main shaft as R, 5‰R < G2 < 10‰R.

[0014] Preferably, a rolling bearing is mounted axially alongside the radial magnetic bearing.

[0015] As a preferred embodiment, with the bearing clearance of the rolling bearing being G3, we have G2 < G3 < G1.

[0016] Preferably, the pump casing is equipped with a heat insulation layer that separates the normal temperature zone from the high temperature zone; the motor, rolling bearing, radial magnetic bearing and axial thrust magnetic bearing are located in the normal temperature zone.

[0017] The beneficial effects of this solution are as follows: Based on the operating environment and structural characteristics of the submersible high-temperature pump, an innovative solution using a combination of magnetic bearings and sliding bearings is adopted, which leverages the advantages of each type of bearing, takes into account the reliability and lifespan of the equipment, reduces the complexity of the equipment, simplifies the structure, lowers the cost, brings significant economic benefits, and reduces the manufacturing and maintenance costs of the equipment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a structural diagram of the shaft system of this utility model; Figure 3 yes Figure 2 Enlarged view of part A; Figure 4 yes Figure 2 Enlarged view of part B.

[0019] The components include: motor 1, rolling bearing 2, radial magnetic bearing 3, axial thrust magnetic bearing 4, heat insulation layer 5, main shaft 6, pump casing 7, sliding bearing 8, and impeller 9. Detailed Implementation

[0020] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0021] This embodiment focuses on a submersible high-temperature pump, primarily used for pumping requirements in a liquid metal preparation process. In the liquid metal preparation industry, pumping equipment faces extremely high demands. It must not only withstand high-temperature environments but also ensure stable and efficient operation under complex conditions to guarantee the continuity of the production process and product quality. The submersible high-temperature pump of this embodiment is meticulously designed to meet these stringent requirements.

[0022] See Figure 1 , Figure 2 As shown, the submersible high-temperature pump in this embodiment mainly consists of key components such as a motor 1, an axial thrust magnetic bearing 4, a heat insulation layer 5, a main shaft 6, a pump casing 7, a sliding bearing 8, and an impeller 9. The pump casing 7 is placed vertically, which facilitates the smooth flow of liquid metal within the pump, reduces flow resistance, and improves pumping efficiency. The main shaft 6 is housed within the pump casing 7 and serves as the core transmission component of the entire pump; its precision and stability directly affect the pump's performance.

[0023] The upper end of the main shaft 6 is connected to the motor 1, which serves as the power source, providing the necessary power for the rotation of the main shaft 6 to the entire pump system. The motor 1 is typically a high-performance special motor, capable of stable operation in high-temperature environments, and its output power and speed can be precisely matched to the actual pumping requirements of the liquid metal. An impeller 9 is installed near the lower end of the main shaft 6. The impeller 9 is a key working component of the pump, and its design shape and dimensions are carefully optimized to ensure that it can effectively drive the liquid metal from the inlet during rotation (…). Figure 1 The liquid flows upward from the lower middle part and from the outlet ( Figure 1 (Bottom right) flows downwards. This unique flow path design facilitates the circulation and mixing of liquid metal during the preparation process, improving preparation efficiency and quality.

[0024] To ensure the stability and reliability of the pump during operation, the upper and lower ends of the pump casing 7 are firmly fixed. An axial thrust magnetic bearing 4 is installed above the main shaft 6, near the motor side. The axial thrust magnetic bearing 4 employs advanced electromagnetic control technology, a significant technological innovation of this embodiment. This technology can monitor the magnitude of the axial thrust generated by the main shaft 6 during operation in real time and accurately, and quickly adjust the magnitude and direction of the electromagnetic force based on the monitoring results. Through this dynamic adjustment, the axial thrust magnetic bearing 4 provides stable and reliable axial support to the main shaft 6, effectively preventing excessive displacement in the axial direction. During liquid metal pumping, the main shaft 6 is subjected to complex axial forces due to the flow and pressure changes of the liquid metal. Without the precise support of the axial thrust magnetic bearing 4, the main shaft 6 may experience axial movement, leading to serious problems such as pump seal failure and impeller-to-casing collision, affecting the normal operation and service life of the pump. The application of the axial thrust magnetic bearing 4 fundamentally solves these problems, ensuring stable operation of the pump in the axial direction.

[0025] A sliding bearing 8 is installed below the main shaft 6, near the impeller 9. Located between the main shaft 6 and the pump housing 7, the sliding bearing 8 primarily ensures the stability of the lower end of the main shaft 6 during rotation. In the high-temperature environment of liquid metal, the sliding bearing 8 needs to possess excellent high-temperature resistance and self-lubricating properties. In this embodiment, the sliding bearing 8 utilizes special materials and manufacturing processes. Its friction pair surfaces undergo precision machining and special treatment, enabling the formation of a stable lubricating film at high temperatures, reducing friction and wear, and ensuring smooth operation of the main shaft 6 during high-speed rotation. Simultaneously, the large clearance design of the sliding bearing 8 is also a highlight of this embodiment. This design significantly reduces the risk of blockage and shaft jamming, because some tiny impurity particles may exist in the liquid metal. If the sliding bearing clearance is too small, these impurity particles can easily get stuck in the bearing clearance, leading to poor bearing operation or even seizure. The large clearance design provides sufficient space for impurity particles to pass through, improving the bearing's adaptability to complex media environments.

[0026] This embodiment also includes a heat insulation layer 5 installed inside the pump casing 7, which axially divides the pump casing 7 into upper and lower parts. The upper part corresponds to the normal temperature zone, where the motor 1 and the axial thrust magnetic bearing 4 are located. The design of the normal temperature zone provides a suitable working environment for the motor 1 and the axial thrust magnetic bearing 4, avoiding damage to electronic components and precision parts from high temperatures, extending their service life, and improving the reliability of the equipment. The lower part corresponds to the high temperature zone, where the sliding bearing 8 and the impeller 9 are located and immersed in liquid metal. This partitioned design fully considers the operating temperature requirements of different components, achieving an optimized layout of the equipment.

[0027] In actual operation, after the motor 1 starts, it drives the main shaft 6 to rotate, and the impeller 9 rotates accordingly, starting to pump liquid metal. The axial thrust magnetic bearing 4 adjusts the axial support force in real time to ensure the stability of the main shaft 6 in the axial direction; the sliding bearing 8 provides stable support to the lower end of the main shaft 6 in the high-temperature zone, ensuring the smooth rotation of the main shaft 6. With the coordinated work of all components, the entire pump system can efficiently and stably complete the pumping task of liquid metal, meeting the process requirements of the liquid metal preparation process. This embodiment serves as the basic embodiment of this solution, providing a solid foundation and important reference for the further evolution and optimization of subsequent embodiments.

[0028] Example 2 Example 2 is a further evolution and optimization based on Example 1, aiming to further improve the performance and reliability of the submersible high-temperature pump.

[0029] In this embodiment, a radial magnetic bearing 3 is installed above the main shaft 6 near the motor 1. The radial magnetic bearing 3 is mounted axially beside the axial thrust magnetic bearing 4. This layout design fully utilizes the space within the pump housing 7 and simultaneously provides multi-directional support for the main shaft 6. The radial magnetic bearing 3 also employs electromagnetic control technology, one of the core applications of modern magnetic levitation technology. This technology, by setting multiple electromagnetic coils and sensors inside the radial magnetic bearing 3, can monitor the radial displacement of the main shaft 6 in real time and with precision. When the main shaft 6 experiences radial displacement due to factors such as uneven flow of liquid metal or load changes during operation, the sensors immediately detect this change and feed the signal back to the control system. The control system quickly calculates the magnitude and direction of the electromagnetic force that needs adjustment based on the feedback signal and achieves radial support and correction of the main shaft 6 by controlling the current in the electromagnetic coils. Through this dynamic adjustment, the radial magnetic bearing 3 ensures stable operation of the main shaft 6 in the radial direction, effectively reducing radial wobble and improving the pump's operating accuracy and stability.

[0030] See further Figure 3 , Figure 4 As shown, the bearing clearance of the radial magnetic bearing 3 is G1, and the bearing clearance of the sliding bearing 8 is G2, where G2 < G1. In traditional sliding bearing designs, the single-sided clearance between friction pairs is typically about 1‰-2‰ of the main shaft radius R. However, the lower medium-lubricated sliding bearing 8 in this design adopts a large clearance design, with its single-sided clearance G2 being enlarged to 5‰R - 10‰R. This large clearance design has significant advantages. During the pumping of liquid metal, the liquid metal may contain a certain amount of impurity particles. If the sliding bearing clearance is too small, these impurity particles are easily stuck in the bearing clearance, leading to poor bearing operation or even seizure, seriously affecting the normal operation of the pump. The large clearance design provides sufficient space for impurity particles to pass through, greatly reducing the risk of blockage and shaft seizure, and improving the adaptability and reliability of the bearing in complex media environments.

[0031] During normal operation, the submersible high-temperature pump is supported at two points: a radial magnetic bearing 3 at the top and a sliding bearing at the bottom. This two-point support method has many advantages, effectively avoiding the swaying problem of a long cantilever. With traditional single-point support or improper support methods, the main shaft 6 is prone to significant swaying during high-speed rotation, leading to uneven clearance between the impeller and the pump casing, affecting the pump's flow rate and head, and increasing wear and vibration. The two-point support method allows the main shaft 6 to maintain a relatively stable state during rotation, reducing sway amplitude and improving the pump's operational stability and efficiency. Furthermore, the two-point support method also improves bearing operating conditions. The radial magnetic bearing 3 and the sliding bearing 8, when supporting the main shaft 6, can rationally distribute the load, reducing the force on individual bearings, lowering bearing wear and fatigue damage, and extending bearing service life.

[0032] The radial magnetic bearing 3 inherently possesses the characteristic of zero-contact friction, which is a significant advantage over traditional mechanical bearings. In traditional mechanical bearings, contact friction generates substantial heat and wear, increasing energy loss and shortening bearing lifespan. The radial magnetic bearing 3, however, uses electromagnetic force to levitate and support the main shaft 6, avoiding contact friction and thus reducing energy loss and wear, improving equipment operating efficiency and reliability. Furthermore, the radial magnetic bearing 3 is positioned in the upper, ambient temperature region, allowing it to operate within a suitable temperature environment. This avoids the impact of high temperatures on electromagnetic components and the control system, further enhancing operational reliability and ease of maintenance.

[0033] Furthermore, thanks to the automatic balancing advantage of the radial magnetic bearing 3, the spindle's operating trajectory can be limited to a smaller range (much smaller than G1). Because the spindle 6's operating trajectory is effectively controlled, the stiffness requirement of the bottom sliding bearing 8 is reduced, allowing for a more appropriate increase in its friction pair clearance. This design further optimizes the performance of the sliding bearing 8, ensuring stable support for the spindle 6 while reducing friction and wear problems caused by excessively small clearances, thus improving the service life and reliability of the sliding bearing 8.

[0034] Based on Example 1, this embodiment further improves the performance and reliability of the submersible high-temperature pump by adding a radial magnetic bearing 3 and optimizing the clearance of the sliding bearing 8, providing a more stable and efficient pumping device for the liquid metal preparation process.

[0035] Same as Example 1.

[0036] Example 3 Example 3 is a further evolution and optimization based on Example 2, aiming to create a more advanced and reliable submersible high-temperature pump to meet the increasingly stringent industrial application requirements.

[0037] In this embodiment, a rolling bearing 2 is also installed above the main shaft 6 near the motor 1. The rolling bearing 2 is positioned close to the radial magnetic bearing 3, so that in the room temperature zone, the order from top to bottom along the axial direction is: motor 1, rolling bearing 2, radial magnetic bearing 3, and axial thrust magnetic bearing 4. This layout design is an important innovation of this embodiment, as it fully considers the characteristics and advantages of different types of bearings and achieves an optimized combination of multiple bearings.

[0038] See further Figure 3 , Figure 4 As shown, with the bearing clearance of rolling bearing 2 as G3, G2 < G3 < G1. The main design significance of rolling bearing 2 is to provide a reliable backup function. During the operation of the submerged high-temperature pump, although radial magnetic bearing 3 has many advantages, its electromagnetic control technology involves complex electronic components and control systems, posing a certain risk of failure. Once radial magnetic bearing 3 fails, without a backup support device, the main shaft 6 will lose radial support, leading to uncontrolled pump operation and potentially causing serious equipment damage and production accidents. The rolling bearing 2 installed in this embodiment effectively solves this problem. When radial magnetic bearing 3 fails, rolling bearing 2 can immediately take over the function of supporting the main shaft 6, continuing the unit's operation and avoiding sudden shutdown. This backup design greatly improves the reliability and safety of the pump system, reducing production interruptions and losses caused by equipment failure.

[0039] Because the bearing clearance G3 of the rolling bearing 2 is smaller than the bearing clearance G1 of the radial magnetic bearing 3, collisions are avoided when the radial magnetic bearing 3 fails. When the radial magnetic bearing 3 fails, the spindle 6 may experience some displacement under the influence of gravity, fluid dynamics, etc. If the clearance of the rolling bearing 2 is too large, the spindle 6 may collide with the inner or outer ring of the rolling bearing 2 during displacement, leading to bearing damage and further deformation of the spindle. The reasonable clearance design in this embodiment ensures that the spindle 6 can operate smoothly under the support of the rolling bearing 2 when the radial magnetic bearing 3 fails, avoiding collision accidents.

[0040] Furthermore, since the rolling bearing 2 is only used in case of failure of the radial magnetic bearing 3, its operating time is short. Under normal circumstances, the radial magnetic bearing 3 provides stable and reliable support for the main shaft 6, while the rolling bearing 2 is in standby mode and bears almost no load or wear. Therefore, the lifespan of the rolling bearing 2 is significantly extended compared to traditional pump sets. In traditional pump sets, rolling bearings typically serve as the main support components, bearing large loads and friction for extended periods, making them prone to wear and damage, and requiring frequent replacement. However, the rolling bearing 2 in this embodiment, due to its low usage frequency and minimal wear, can significantly reduce the number of replacements, thereby reducing equipment maintenance costs and downtime.

[0041] Same as Example 2.

[0042] This embodiment demonstrates the three significant features of this solution: Feature 1: A novel submersible high-temperature pump assembly structure is proposed, employing a combination of magnetic bearings, rolling bearings, and sliding bearings. This combined structure fully leverages the advantages of different bearing types. Magnetic bearings offer advantages such as non-contact friction and automatic balancing, enabling high-precision support and stable operation of the main shaft. Rolling bearings are characterized by simple structure, high load-bearing capacity, and high reliability, serving as a backup support device to ensure normal operation of the equipment in the event of magnetic bearing failure. Sliding bearings offer advantages such as high-temperature resistance and adaptability to complex media, providing stable support for the main shaft in high-temperature liquid metal environments. The organic combination of these three types of bearings forms a high-performance, highly reliable submersible high-temperature pump assembly structure, providing powerful equipment support for liquid metal preparation processes.

[0043] Feature Two: It fully leverages the automatic balancing capability of magnetic bearings and the greater stability and reliability of sliding bearings. The lower bearing uses a sliding bearing with a larger clearance. This design reduces blockages and shaft jamming caused by impurities or properties in the medium. During liquid metal pumping, the medium may contain various impurity particles. If the sliding bearing clearance is too small, these particles can easily get stuck, affecting the normal operation of the bearing. The large clearance design provides sufficient space for these particles to pass through, improving the adaptability of the sliding bearing in complex media environments. Simultaneously, the automatic balancing capability of the magnetic bearing can adjust the position of the main shaft in real time, ensuring the stability of the main shaft during operation and further improving the overall performance of the pump.

[0044] Feature Three: The number of electrical components is significantly reduced, resulting in a simpler structural design and control system, lowering costs while improving equipment reliability. In traditional submersible high-temperature pump designs, achieving precise support and control of the spindle often requires numerous electrical components and complex control systems, increasing both equipment cost and the probability of failure. This embodiment, however, utilizes a rational combination of different types of bearings, fully leveraging the advantages of each bearing and reducing reliance on complex electrical control systems. The synergistic operation of magnetic bearings, rolling bearings, and sliding bearings makes the pump's structural design simpler and more straightforward, and the control system relatively straightforward as well, thereby reducing manufacturing and maintenance costs while improving equipment reliability and stability.

[0045] This embodiment, as a preferred embodiment of the solution, further improves the performance and reliability of the submersible high-temperature pump by adding a rolling bearing 2 and optimizing the bearing layout and clearance, providing a more advanced and practical pumping solution for the liquid metal preparation industry.

Claims

1. A submersible high-temperature pump, comprising a main shaft (6) driven to rotate by a motor (1), wherein an axial thrust magnetic bearing (4) is mounted on the motor end of the main shaft (6), and the impeller end of the main shaft (6) is submerged in a high-temperature medium, characterized in that, It also includes a pump housing (7) and a sliding bearing (8); The main shaft (6) extends into the pump housing (7), and the sliding bearing (8) is installed between the main shaft (6) and the pump housing (7).

2. The submersible high-temperature pump according to claim 1, characterized in that, The sliding bearing (8) is installed on the main shaft (6) near the impeller (9).

3. A submersible high-temperature pump according to claim 1 or 2, characterized in that, A radial magnetic bearing (3) is installed on the axial side of the axial thrust magnetic bearing (4).

4. The submersible high-temperature pump according to claim 3, characterized in that, Let the bearing clearance of the radial magnetic bearing (3) be G1 and the bearing clearance of the sliding bearing (8) be G2, then G2 < G1.

5. The submersible high-temperature pump according to claim 4, characterized in that, With the radius of the main axis (6) as R, we have 5‰R<G2<10‰R.

6. The submersible high-temperature pump according to claim 4, characterized in that, A rolling bearing (2) is mounted on the axial side of the radial magnetic bearing (3).

7. A submersible high-temperature pump according to claim 6, characterized in that, With the bearing clearance of the rolling bearing (2) as G3, we have G2 < G3 < G1.

8. A submersible high-temperature pump according to claim 6, characterized in that, The pump casing (7) is equipped with a heat insulation layer (5) that separates the normal temperature zone from the high temperature zone; the motor (1), rolling bearing (2), radial magnetic bearing (3) and axial thrust magnetic bearing (4) are located in the normal temperature zone.

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