High temperature medium pump phase change self-lubricating bearing device

Abstract

The application relates to a high-temperature medium pump phase-change self-lubricating bearing device, which comprises a phase-change molten medium, a temperature control retainer, a temperature control system and a rotating shaft; the temperature control retainer is fixedly arranged, the temperature control retainer is internally communicated with cooling medium, and the cooling medium is connected with the temperature control system; the rotating shaft is rotationally arranged at the center position of the temperature control retainer; the phase-change molten medium covers the outside of the temperature control retainer; the temperature control system controls the temperature of the temperature control retainer, so that the phase-change molten medium close to the temperature control retainer is solidified to form a solid-state medium shell; an annular gap is formed between the solid-state medium shell and the rotating shaft; and the rotating shaft drives the phase-change molten medium in the gap to form dynamic pressure support. The application realizes self-lubrication by relying on medium solid-liquid phase change, can adjust the lubricating gap through temperature control, is matched with a medium in-situ self-repairing structure, and overcomes the defects of traditional high-temperature medium lubricating bearings, such as easy failure, serious bearing wear and easy shaft holding.

Description

Technical Field

[0001] This invention relates to the field of bearing technology for molten salt equipment, and more specifically to a phase change self-lubricating bearing device for a high-temperature medium pump. Background Technology

[0002] Molten salt reactors are a key candidate reactor type for fourth-generation nuclear energy. The Chinese Academy of Sciences launched a special research project on thorium-based molten salt nuclear energy systems (TMSR) in 2011, and achieved full-power operation of the relevant experimental reactor in 2024. Molten salt energy storage, as a novel thermal energy storage technology, relies on molten salt thermal energy storage and phase change thermal energy storage to achieve energy storage, and its application scale continues to expand. In the complete set of equipment for molten salt reactors and molten salt energy storage, the molten salt pump is a core and critical piece of equipment, and the bearing, as a core component of the molten salt pump, directly determines the overall operational reliability of the molten salt pump.

[0003] Molten salt conditions are characterized by high temperatures (up to 700℃) and strong corrosiveness, and the operating environment of molten salt reactors is also affected by the corrosion of fission products. Existing conventional molten salt pumps generally use traditional sliding bearing structures. Under the high-temperature molten salt service environment, the combined effects of molten salt corrosion, fission product corrosion, and high-speed friction result in prominent defects such as rapid friction loss, short service life, and easy seizing and jamming during operation. Summary of the Invention

[0004] In order to solve the problems of easy wear and short life of bearings in molten salt environment in the prior art, the present invention aims to provide a phase change self-lubricating bearing device for high temperature medium pumps.

[0005] The high-temperature medium pump phase change self-lubricating bearing device according to the present invention includes a phase change molten medium, a temperature-controlled retainer, a temperature control system, and a rotating shaft. The temperature-controlled retainer is fixedly arranged, and a cooling medium is connected inside the retainer. The cooling medium is connected to the temperature control system. The rotating shaft is rotatably mounted at the center of the retainer. The phase change molten medium covers the outside of the retainer. The temperature control system regulates the temperature of the retainer, causing the phase change molten medium adhering to the retainer to solidify into a solid medium shell. An annular gap is formed between the solid medium shell and the rotating shaft. The rotation of the shaft drives the phase change molten medium within the gap to form a hydrodynamic support. This invention, by relying on the solid-liquid differentiation of the phase change molten medium to construct a zoned lubrication structure, can achieve hydrodynamic support by the medium itself without the need for external lubricating grease. This adapts to harsh corrosive conditions and avoids the short lifespan of conventional medium-lubricated bearings.

[0006] In a preferred embodiment, the temperature-controlled retainer consists of an inner liner and an outer bladder. The inner liner forms a sealed cavity, and the outer bladder has a porous mesh structure. The phase-change melting medium is filled inside the mesh pores of the outer bladder. This invention, by adopting a unique retainer structure with a separate inner liner and outer bladder and a mesh structure for filling the medium, breaks through the limitations of traditional one-piece smooth sleeve structures and provides arrangement space for medium embedding and curing.

[0007] In a preferred embodiment, the mesh structure of the outer shell forms a skeletal constraint on the solid medium shell, simultaneously increasing the heat exchange contact area. This invention, by forming an embedded skeletal constraint structure for the solidified medium through the mesh structure, can improve the heat exchange efficiency of the hot and cold media and make the temperature control response more sensitive, while also preventing the solid medium from cracking and falling off, thus stabilizing the overall structural morphology of the solid medium shell.

[0008] In a preferred embodiment, the hardness of the material used for the shaft is greater than the hardness of the solid medium shell. By limiting the hardness ratio between the shaft and the solid medium, this invention can avoid shaft wear damage during operation and preferentially consume the solid medium to achieve flexible friction fit.

[0009] In a preferred embodiment, the temperature control system adjusts the thickness of the solid medium shell by changing the temperature of the cooling medium, thereby altering the annular gap size. This invention, by linking temperature control with the solid medium shell thickness to fine-tune the lubrication gap, overcomes the limitation of traditional bearings having a fixed, non-adjustable factory clearance, achieving online stepless adjustment of the bearing's load-bearing capacity.

[0010] In a preferred embodiment, a container is also provided, inside which the phase change molten medium is stored. By adding an independent container to centrally store the phase change molten medium, this invention enables airtight storage of the medium, facilitates temperature control of the medium, and is suitable for application scenarios without native high-temperature environments.

[0011] In a preferred embodiment, a heating and insulation device is provided on the outer wall of the container to maintain the phase change molten medium inside the container in a molten state. By providing a heating and insulation structure on the outside of the container, this invention can continuously ensure that the medium remains in a molten state, providing the basic operating conditions for the medium to undergo in-situ phase change solidification and form a solid lubricating layer.

[0012] In a preferred embodiment, when the working environment can maintain the phase change melting medium in a molten state, the container and heating and insulation device are removed. This invention, through its modular design with detachable and optional containers and heating and insulation devices, can adapt to working environments with built-in high-temperature heat sources, simplifying equipment components and reducing the overall space occupied by the machine.

[0013] In a preferred embodiment, the temperature-controlled retainer is made of a thermally conductive material that is chemically compatible with the phase-change melting medium. By using a specially formulated material with high thermal conductivity and excellent chemical compatibility with the medium, this invention accelerates heat exchange efficiency, achieves precise temperature control, and simultaneously prevents corrosion of the retainer by the high-temperature medium, thus extending its service life.

[0014] In a preferred embodiment, the phase-change molten medium within the annular gap self-repairs by replenishing the worn areas after the shaft wears down to the solid medium shell, relying on phase change to compensate for the damage. This invention, through a phase-change self-repair mechanism where the molten medium solidifies in situ upon cooling, can automatically fill the wear gaps in the solid medium, maintain the lubrication gap size stably over a long period, and significantly extend the overall service life of the bearing.

[0015] This invention relies on a phase-change molten medium to form a solid-liquid partition lubrication structure on the outside of a temperature-controlled cage. The temperature control system adjusts the thickness of the solid medium shell and the lubrication gap. Combined with a grid frame to reinforce the solid medium and a design that allows for in-situ phase-change self-repair after wear, this invention solves industry problems such as lubrication failure, high bearing friction loss, and easy shaft seizure under high-temperature and corrosive conditions. Furthermore, the container and heating / insulation devices can be flexibly selected according to site conditions to adapt to different operating environments. While ensuring stable dynamic pressure lubrication support for the rotating shaft, it effectively extends the overall service life of the bearing, significantly improving the operational stability and applicability of the device under harsh molten medium conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the phase change self-lubricating bearing device for the high-temperature medium pump of the present invention.

[0017] Figure 2 This is a schematic cross-sectional view of the temperature control holder in this invention. Detailed Implementation

[0018] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0019] like Figure 1 As shown, the high-temperature medium pump phase change self-lubricating bearing device according to the present invention includes a rotating shaft 1, a temperature control retainer 2, a cooling medium 3, a container 4, a temperature control system 5, a heating and heat preservation device 6, and a phase change melting medium 7.

[0020] The molten medium can be nitrates, fluorides, and other high-temperature media with phase change melting characteristics, and the applicable temperature is greater than 100℃.

[0021] The temperature control retainer 2 is fixed in place after assembly, with a through hole in its center. The temperature control retainer 2 is made of materials with high thermal conductivity and excellent chemical compatibility with the phase change molten medium 7, such as nickel, GH3535, or graphite, carbon fiber, or other non-metallic materials. It should be understood that excellent chemical compatibility with the phase change molten medium 7 refers to excellent chemical stability under high-temperature conditions; the two will not react chemically. The temperature control retainer 2 is internally connected to the cooling medium 3, which is connected to the temperature control system 5 via external piping. The temperature control system 5 enables the circulation and precise temperature control of the cooling medium 3. The cooling medium 3 can be a gas or a liquid; inert gas can be used, and liquid options include heat transfer oil, pure water, sodium-potassium alloy, and low-melting-point molten salt.

[0022] The rotating shaft 1 is inserted into the central through hole of the temperature control holder 2 and can rotate around its own axis, forming a rotating pair. The rotating shaft 1 is made of high-temperature wear-resistant material, and the hardness of the material itself is greater than the hardness of the solid phase change molten medium 7 after solidification. Materials such as ceramics, GH3535, Stellite alloy, and high entropy alloys, or other metallic or non-metallic materials, can be selected.

[0023] Container 4 is a hollow cavity structure used to centrally hold the phase change molten medium 7. The outer side of the temperature control holder 2 is completely immersed in the phase change molten medium 7 inside the container 4, and the rotating shaft 1 is also partially immersed in the phase change molten medium 7.

[0024] The heating and heat preservation device 6 is fixedly arranged on the outer wall of the container 4 to continuously heat and preserve the phase change molten medium 7 inside the container 4, so that the phase change molten medium 7 is normally kept in a molten liquid state.

[0025] like Figure 2 As shown, the temperature control retainer 2 is composed of an inner liner 2-1 and an outer bladder 2-2. The inner liner 2-1 is a sealed cavity structure, and the interior of the cavity is used to circulate and contain the cooling medium 3. The outer bladder 2-2 is fixedly attached to the outside of the inner liner 2-1. The outer bladder 2-2 adopts a porous mesh frame hollow structure, and the porous space of the mesh frame of the outer bladder 2-2 is filled with a phase change molten medium 7. After the phase change molten medium 7 solidifies, the mesh frame is embedded inside the solid medium, which not only greatly increases the heat exchange contact area, but also provides constraint and reinforcement to the solid medium through the mesh frame skeleton, preventing the solid medium from breaking and falling off, and improving the overall structural strength of the solid medium.

[0026] Cooling medium 3 is introduced into the sealed inner liner 2-1 of the temperature control holder 2, and forced circulation heat exchange is achieved under the control of the temperature control system 5. The cooling medium can be a gaseous medium or a liquid medium. The temperature control system 5 precisely controls the overall outer wall temperature of the temperature control holder 2 by changing the temperature of the cooling medium 3, and adjusts the thickness of the solid medium shell to change the size of the annular gap.

[0027] The phase change molten medium 7 fills the inner cavity of the container 4 and the mesh pores of the outer bladder 2-2 of the temperature control holder 2. Under normal conditions, it is in a molten liquid state after being heated by the heating and heat preservation device 6. When it comes into contact with the low-temperature outer wall of the temperature control holder 2, it can undergo a solidification phase change and form a solid shell.

[0028] The overall working process of the device is briefly described below.

[0029] After the equipment is started, the heating and insulation device 6 on the outside of container 4 continues to work, heating all the phase change molten medium 7 inside container 4 to a molten liquid state; the temperature control system 5 is activated, and the temperature control system 5 regulates the temperature of the cooling medium 3 and circulates inside the inner liner 2-1, continuously removing the heat from the temperature control holder 2, so that the temperature of the outer wall of the temperature control holder 2 is lower than the solidification melting point of the phase change molten medium 7; the phase change molten medium 7 that is in close contact with the outer wall of the temperature control holder 2 is cooled and gradually solidifies to form a solid medium shell. The solid medium shell grows outward from the outer wall of the temperature control holder. Due to the temperature gradient limitation, the solid medium cannot extend to the surface of the rotating shaft 1, and finally a ring gap is formed between the solid medium shell and the rotating shaft 1. The phase change molten medium 7 inside the gap remains liquid due to the influence of the high ambient temperature.

[0030] During equipment operation, the rotating shaft 1 continuously rotates. The liquid phase-change molten medium inside the annular gap forms a liquid film under the action of rotational dynamic pressure. This dynamic pressure effect enables the shaft 1 to be suspended and supported, thus completing the bearing's load-bearing lubrication. Operators can fine-tune the temperature of the cooling medium 3 through the temperature control system 5, thereby changing the temperature of the outer wall of the temperature-controlled cage 2: lowering the cage temperature increases the thickness of the solid medium shell and reduces the annular lubrication gap, increasing the bearing's support capacity; raising the cage temperature melts some of the solid medium, thins the medium shell, and increases the lubrication gap, reducing the bearing's support capacity. This achieves stepless adjustment of the bearing's support performance.

[0031] During the long-term operation of the bearing, the friction of the shaft 1 will wear down the local solid medium shell. The phase change molten medium 7 in the molten state around the wear location will recrystallize under the action of the low temperature shell, automatically filling the wear gap and realizing the self-repair of the lubricating medium. The wear-repair and recrystallization are in a continuous dynamic balance, making the theoretical service life of the bearing approach infinity.

[0032] It should be understood that the above embodiments are preferred embodiments of the present invention. In practical applications, by adjusting the thickness of the solid medium shell to change the annular gap size, the container 4 and the heating and heat preservation device 6 can be eliminated, and the temperature control holder 2 and the rotating shaft 1 can be directly immersed in the molten phase change medium 7 provided by the working environment, while the remaining structure and temperature control and lubrication principles remain unchanged; the materials of the temperature control holder 2 and the rotating shaft 1 can be flexibly replaced according to the type of medium and the operating temperature. Any simple equivalent substitutions made based on the structure of this solution fall within the protection scope of the present invention.

Claims

1. A phase change self-lubricating bearing device for a high-temperature medium pump, characterized in that, It includes a phase change melting medium, a temperature-controlled retainer, a temperature control system, and a rotating shaft. The temperature-controlled retainer is fixedly arranged, and a cooling medium is connected inside the temperature-controlled retainer. The cooling medium is connected to the temperature control system. The rotating shaft is rotatably assembled at the center of the temperature-controlled retainer. The phase change melting medium covers the outside of the temperature-controlled retainer. The temperature control system regulates the temperature of the temperature-controlled retainer, causing the phase change melting medium in close contact with the temperature-controlled retainer to solidify into a solid medium shell. An annular gap is formed between the solid medium shell and the rotating shaft. The rotation of the rotating shaft drives the phase change melting medium in the gap to form a dynamic pressure support.

2. The high-temperature medium pump phase change self-lubricating bearing device according to claim 1, characterized in that, The temperature control holder consists of an inner liner and an outer bladder. The inner liner forms a sealed cavity, and the outer bladder has a porous mesh structure. The phase change melting medium is filled inside the mesh pores of the outer bladder.

3. The high-temperature medium pump phase change self-lubricating bearing device according to claim 2, characterized in that, The outer shell's mesh structure forms a skeletal constraint on the solid medium shell, simultaneously increasing the heat exchange contact area.

4. The phase change self-lubricating bearing device for a high-temperature medium pump according to claim 1, characterized in that, The material used for the shaft is harder than the material used for the solid dielectric shell.

5. The high-temperature medium pump phase change self-lubricating bearing device according to claim 1, characterized in that, The temperature control system changes the annular gap size by adjusting the thickness of the solid medium shell by changing the temperature of the cooling medium.

6. The phase change self-lubricating bearing device for a high-temperature medium pump according to claim 1, characterized in that, It is also equipped with a container, which contains the phase change melting medium.

7. The high-temperature medium pump phase change self-lubricating bearing device according to claim 6, characterized in that, The outer wall of the container is equipped with a heating and insulation device to keep the phase change melting medium inside the container in a molten state.

8. The phase change self-lubricating bearing device for a high-temperature medium pump according to claim 7, characterized in that, When the working environment can maintain the phase change melting medium in a molten state, remove the container and heating and insulation device.

9. The phase change self-lubricating bearing device for a high-temperature medium pump according to claim 1, characterized in that, The temperature-controlled retainer is made of a thermally conductive material that is chemically compatible with the phase change melting medium.

10. The phase change self-lubricating bearing device for a high-temperature medium pump according to claim 1, characterized in that, After the solid medium shell is worn by the rotating shaft, the phase change molten medium in the annular gap can achieve structural self-repair by replenishing the loss position through phase change.

Images