Detachable impurity filtration and adsorption type lead-cooled fast reactor ceramic main pump impeller device

Abstract

The invention belongs to the technical field of circulating purification of liquid metal cooling reactor main pump impellers, and particularly relates to a detachable impurity filtering and adsorbing type lead cooling fast reactor ceramic main pump impeller device. Comprising a ceramic impeller, a supporting pressure plate, a double-tower type metal rubber assembly, a screw-in end cover, a suction end cover, an axial flow pump shell, a transmission shaft, a protection support, a rotating motor, a coupler and a bearing cover. The double-tower type metal rubber assembly is made of stainless steel wires through winding, weaving and cold stamping, the tower type structure increases the specific surface area, multi-stage through holes are formed, and oxides and solid particles in a liquid coolant can be adsorbed in a layered mode; in the pressed state, the metal rubber continuously provides pre-tightening force for the impeller body and outputs high damping, and axial vibration is remarkably restrained. And the filter assembly can be quickly disassembled and assembled and can be replaced under the condition of no shutdown. The main pump impeller has the advantages of purification, adsorption, vibration reduction and maintainability, and the service life of the main pump impeller in a high-temperature liquid metal environment is remarkably prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of liquid metal cooled reactor main pump impeller circulation purification, and particularly relates to a detachable impurity filtering and adsorbing type lead-cooled fast reactor ceramic main pump impeller device, which is a detachable impurity filtering and adsorbing-vibration damping and pre-tightening integrated lead-cooled fast reactor ceramic main pump impeller device. BACKGROUND

[0002] Lead-cooled fast reactor (LFR) and lead-bismuth-cooled fast reactor (LBE-FR) are important representatives of the fourth generation nuclear energy system. The main pump is immersed in high-temperature liquid metal coolant at 350-500 DEG C for a long time, and is subjected to severe erosion and fluid-structure coupling vibration caused by high-density and low-viscosity fluid. The axial pre-tightening of the current main pump ceramic impeller mainly depends on single spring gasket or disc spring device. Such traditional elastic elements are prone to stress relaxation and creep deformation in high-temperature environment, resulting in rapid attenuation of pre-tightening force and insufficient axial stability. High-temperature liquid lead / lead bismuth has strong corrosiveness to structural materials, and metal components will dissolve into the coolant to form metal oxide particles. Metal oxide particles deposit in low-temperature areas or areas with low flow rate, causing pipe blockage and heat transfer efficiency reduction. In addition, the existing suction end cover structure has single function and cannot effectively pre-rotate and rectify the coolant, which seriously restricts the subsequent purification efficiency and flow stability.

[0003] Metal rubber (MR) is a new multifunctional material made of metal wires (such as stainless steel) with a diameter of 0.1-0.3 mm by winding, weaving and cold stamping processes. Its essence is a nonlinear porous metal elastomer with adjustable porosity of 30-70% and excellent structure recovery capability. The three-dimensional interlaced wire bundles realize high internal friction damping effect through sliding and micro-contact, which significantly suppresses structure vibration. At the same time, its continuous metal skeleton endows it with good high-temperature resistance, liquid metal corrosion resistance and durable and stable mechanical properties. In addition, the internal multi-level pore network of metal rubber also has good filtering and adsorbing capacity, which can effectively capture particle impurities in liquid lead / lead-bismuth coolant.

[0004] Based on the above excellent performance, the metal rubber damping-filtering assembly has been widely used in spacecraft pipeline support, high-temperature steam system, lunar exploration equipment and rocket nozzle sandwich shell in harsh service environment, and has shown significant damping and noise reduction, thermal stability and impurity interception effect. Compared with traditional mechanical damping device or single-stage static filter, MR assembly can not only provide adjustable high damping and precise force-displacement control, but also realize hierarchical adsorption by means of porous network structure, and has excellent service adaptability in high-temperature liquid metal working condition. At present, the integrated application of metal rubber material in the impeller structure of lead-cooled fast reactor main pump also shows good potential, which can realize the integration of pre-tightening, damping and purification functions without increasing the complexity of the system, and provides a new path for improving the operation reliability and long-term maintainability of the fast reactor system. SUMMARY

[0005] The purpose of the present application is to provide a detachable impurity filtering and adsorbing type ceramic main pump impeller device for lead-cooled fast reactor, to overcome the problems of existing lead-cooled fast reactor main pump, such as easy failure at high temperature, difficulty in online separation of impurities, rapid decay of impeller system pre-tightening force and complicated on-site maintenance operation. The device embeds the upper and lower symmetrical double-tower metal rubber assembly in the front end of the impeller body, and cooperates with the spin-in end cover to build a high-damping adjustable pre-tightening system, realizes the integration of hierarchical adsorption of particulate impurities, flow field rectification and axial damping, adopts a spin-off type quick disassembly structure, can replace the components online without disassembling the transmission shaft and impeller, and can realize on-site replacement without stopping the reactor, thereby significantly improving the long-term reliability, damping performance and maintenance efficiency of the main pump.

[0006] The technical scheme of the present application is as follows:

[0007] A detachable impurity filtering and adsorbing type ceramic main pump impeller device for lead-cooled fast reactor, comprising a ceramic impeller 1, a support pressure plate 2, a double-tower metal rubber assembly 3, a spin-in end cover 4, a suction end cover 6, a shaft flow pump shell 7, a transmission shaft 8, a protection support 9, a rotating motor 10, a shaft coupling 11 and a bearing cover 12.

[0008] The ceramic impeller 1 is provided with a positioning hole in the inside along the axial direction for installing the transmission shaft 8, the tail end of the ceramic impeller 1 has a larger diameter than the front end; the output end of the transmission shaft 8 is inserted into the positioning hole from the tail end of the ceramic impeller 1 and extends out of the positioning hole, and the tail end of the ceramic impeller 1 is connected with the shaft shoulder positioning position of the transmission shaft 8; the input end of the transmission shaft 8 is connected with the rotating motor 10 through the shaft coupling 11, and the transmission shaft 8 is provided with the protection support 9 outside, and the both sides of the protection support 9 are provided with openings for the transmission shaft 8 to pass through.

[0009] The support pressure disc 2 and the double-tower metal rubber assembly 3 are installed on the transmission shaft 8, located outside the front end of the ceramic impeller 1, and are attached to each other, and the support pressure disc 2 is located between the double-tower metal rubber assembly 3 and the ceramic impeller 1; the front end of the transmission shaft 8 is provided with a thread, the inner wall of the screw-in end cover 4 is provided with a screw-in thread 5, the screw-in thread 5 is matched with the thread on the front end of the transmission shaft 8, the screw-in end cover 4 is installed on the front end of the transmission shaft 8, and the double-tower metal rubber assembly 3 is pressed tightly.

[0010] The front end of the ceramic impeller 1, the support pressure disc 2, the double-tower metal rubber assembly 3, the screw-in end cover 4 and the transmission shaft 8 are located inside the axial flow pump shell 7; one side of the axial flow pump shell 7 is provided with an opening for the transmission shaft 8 to pass through, one side of the protection bracket 9 provided with an opening is fixedly connected with the side of the axial flow pump shell 7 provided with an opening, and the opposite side and the top are open structures, the top opening is used for connecting and installing with other devices outside, and the suction end cover 6 is installed on the opening of the other side; the bearing cover 12 is arranged on the other side of the protection bracket 9 provided with an opening, so that sealing is realized.

[0011] The support pressure disc 2 is in a disc structure, the inner wall is attached to the transmission shaft 8, one side of the support pressure disc 2 is attached to the front end of the ceramic impeller 1, and the other side is attached to the double-tower metal rubber assembly 3.

[0012] The double-tower metal rubber assembly 3 is in a left-right symmetrical tower structure, and the left and right parts are both horizontally placed conical frustums, and the diameters of the left and right outer end faces are smaller than that of the central axis part, and the double-tower metal rubber assembly 3 is provided with a through opening along the horizontal central axis for the transmission shaft 8 to pass through.

[0013] The suction end cover 6 is in a disc structure, a plurality of spiral splitter blades 13 are symmetrically arranged in the inside, one end of the spiral splitter blade 13 is fixed to the inner wall of the suction end cover 6, the other end is fixed to the outer periphery of the center support disc of the suction end cover 6, and a plurality of spiral flow channels are arranged on the surface of the spiral splitter blade 13.

[0014] The device realizes the integration of solid impurity adsorption and high-damping pre-tightening through structural innovation, and adopts an adjustable pre-tightening and detachable structure, so that the component replacement requirement under the condition of non-stop stacking is met. The filter assembly can be quickly disassembled and replaced under the condition of non-stop stacking. Compared with the traditional elastic washer type pre-tightening mode without purification structure, the device has the advantages of purification, adsorption, vibration reduction and maintainability, significantly prolongs the service life of the main pump impeller in the high-temperature liquid metal environment and reduces the operation and maintenance cost, improves the stable operation ability, pre-tightening durability and coolant cleanliness of the lead-cooled fast reactor main pump system, significantly shortens the maintenance downtime, and has excellent comprehensive engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 This is a schematic diagram of the axonometric structure of the present invention;

[0016] Figure 2 A top view of the structure of the present invention;

[0017] Figure 3 It is a cross-sectional view of the structure of the present invention;

[0018] Figure 4 It is a left side view of the structure of the present invention;

[0019] Figure 5 This is a schematic diagram of the axonometric structure of the impeller body of the present invention;

[0020] Figure 6 It is a structural cross-sectional view of the impeller body of the present invention;

[0021] FIG7( a ) is a schematic diagram of the suction end cover structure of the present invention, and FIG7( b ) is a cross-sectional view taken along line A of FIG7( a ).

[0022] In the figure: 1-impeller, 2-support pressure plate, 3-double-tower metal rubber assembly, 4-screw-in end cover, 5-screw-in thread, 6-suction end cover, 7-axial flow pump housing, 8-drive shaft, 9-protection bracket, 10-rotating motor, 11-coupling, 12-bearing cover, 13-spiral splitter blade. DETAILED DESCRIPTION

[0023] The structure and working process of the device of the present invention will be further described below with reference to the accompanying drawings.

[0024] like Figures 1-6 As shown, the detachable impurity filtering and adsorption type lead-cooled fast reactor ceramic main pump impeller device described in the present invention includes an impeller 1, a supporting pressure plate 2, a double-tower metal rubber assembly 3, a screw-in end cover 4, a suction end cover 6, an axial flow pump housing 7, a transmission shaft 8, a protective bracket 9, a rotating motor 10, a coupling 11, a bearing cover 12 and other components.

[0025] Ceramic impeller 1 has an axially defined locating hole inside for mounting drive shaft 8. The diameter of the impeller's rear end is larger than its front end. The output end of drive shaft 8 is inserted through the rear end of the impeller and extends beyond the hole. The impeller's rear end is then pushed into the shoulder on drive shaft 8 to ensure proper coaxiality. This coaxiality directly impacts the impeller's dynamic balance and vibration characteristics, typically requiring a tolerance of less than 0.01 mm.

[0026] Push the support pressure disc 2 into and install it on the drive shaft 8 at the front end of the ceramic impeller 1, so that the axial positioning surfaces of the two are accurately fitted. The flatness and roughness of the positioning surfaces need to be processed by precision machining (such as grinding or polishing) to below Ra0.8, so as to reduce the assembly error.

[0027] Push the double-tower metal rubber assembly 3 into and install it on the drive shaft 8 at the front end of the ceramic impeller 1, and fit it with the side surface of the support pressure disc 2, to ensure good fitting accuracy.

[0028] The front end of the drive shaft 8 is provided with a screw thread, and the inner wall of the screwed end cover 4 is provided with a screwed thread 5. The screwed end cover 4 is screwed into the front end of the drive shaft 8 along the screwed thread 5 and a screwing force is applied. The degree of screwing of the screwed end cover 4 is controlled to achieve the designed axial compression deformation amount of the double-tower metal rubber assembly 3, thereby providing a stable and reliable pre-tightening force, achieving an ideal damping-filtering effect. The control of the screwing torque is usually realized by a torque wrench. It is recommended that the initial torque be 20-30 Nm, and the specific value needs to be adjusted according to the actual test data. The degree of screwing of the screwed end cover 4 is adjustable, and the torque control is used to adjust the axial compression deformation amount of the metal rubber, so as to realize controllable high-damping output while maintaining high-efficiency impurity adsorption performance, improve the stability of the impeller operation, and slow down the decay of the pre-tightening force.

[0029] The double-tower metal rubber assembly 3 adopts an upper-lower symmetrical tower structure and is pre-tightened by being compressed and screwed into the screwed end cover 4. The screwed end cover 4 is provided with a screwed thread 5 inside. Through the screwing process, the double-tower metal rubber assembly 3 is axially compressed to provide the required axial pre-tightening force and produce a high-efficiency damping effect. The upper-lower symmetry of the tower structure not only enhances the stability of the structure, but also realizes a layered filtering function through multi-stage pore design.

[0030] The screwed end cover 4 can be withdrawn in the threaded direction by unscrewing operation, so that the double-tower metal rubber assembly 3 is completely separated as a whole without the need to disassemble the connection between the ceramic impeller 1 and the drive shaft 8, thereby quickly completing the replacement of the assembly and realizing on-site maintenance under the condition of no shutdown. This design significantly reduces the risk of radiation exposure and shutdown time during maintenance.

[0031] The double-tower metal rubber assembly 3 is made of stainless steel wire with a diameter of 0.1-0.3 mm through winding, weaving, sintering and cold working processes, effectively inhibiting the slip between adjacent metal structures and improving the damping performance; the multi-stage through-pore structure formed inside the metal rubber of the tower structure increases the specific surface area, which can effectively adsorb the oxides and solid particles entrained in the liquid lead / lead-bismuth coolant, and has excellent online impurity trapping capacity. The diameter selection range (0.1-0.3 mm) of the stainless steel wire is based on the balance between porosity and mechanical strength. Too fine wire material may cause excessive porosity and affect fluid passability, and too thick wire may reduce adsorption efficiency.

[0032] The stainless steel wire can be made of 304 stainless steel material, so as to have high temperature resistance and good forming processability, and the hardness and elastic modulus are matched in the heat treatment process, so as to improve the comprehensive performance of damping adsorption. The corrosion resistance and oxidation resistance of 304 stainless steel are excellent below 500 DEG C.

[0033] The ceramic impeller 1 is integrally sintered by Max phase ceramic material, has high strength, corrosion resistance and high temperature resistance, and is precisely ground to ensure coaxial assembly precision and running stability with the transmission shaft 8.

[0034] The suction end cover 6 is fixedly connected with the front end of the axial flow pump shell 7 through bolts, so as to ensure reliable sealing and convenient disassembly. The bolt connection is usually equipped with an O-shaped sealing ring or a metal gasket to prevent high-temperature liquid metal leakage.

[0035] The transmission shaft 8 is provided with a protection support 9, and is connected with the rotating motor 10 through a shaft coupling 11. The protection support plays a role of limiting, stabilizing and resisting vibration, and the shaft coupling can compensate the deviation of shafting centering, so as to ensure that the driving force of the motor is efficiently and stably transmitted to the impeller body.

[0036] As shown in FIGS. 7(a) and 7(b), the suction end cover 6 is a disc structure, and a plurality of spiral distribution vanes 13 are symmetrically arranged in the inside of the disc structure. One end of the spiral distribution vane 13 is fixed to the inner wall of the suction end cover 6, and the other end is fixed to the outer periphery of the center support disc of the suction end cover 6. A plurality of spiral flow channels are arranged on the surface of the spiral distribution vane 13. The spiral distribution vane 13 and the spiral flow channels can uniformly distribute the solid particles when the coolant flows through the flow channels, which is beneficial to improve the efficiency of subsequent impurity adsorption. The geometric parameters (such as the blade angle, the number and the flow channel width) of the spiral distribution vane 13 need to be optimized according to the flow rate and viscosity characteristics of the coolant, so as to ensure the uniformity of the flow field and minimize the pressure loss.

[0037] When the double-tower metal rubber assembly 3 is saturated or the damping performance is attenuated, the connection structure between the ceramic impeller 1 and the transmission shaft 8 does not need to be disassembled, and only the positioning fastening bolt and the rotating end cover 4 need to be loosened, so that the assembly can be taken out as a whole for cleaning or replacement. The cleaning process is recommended to use an ultrasonic cleaning machine, and the cleaning liquid is deionized water or a low-concentration acid solution.

[0038] Through the structure of the application, the impeller body realizes reliable coaxial positioning, adjustable pre-tightening force, efficient damping and multiple functions such as online impurity adsorption. At the same time, the double-tower metal rubber assembly is easy to disassemble and replace, which significantly improves the long-term operation reliability and maintenance convenience of the lead-cooled fast reactor main pump impeller device.

Claims

1. A detachable impurity filtration and adsorption type lead-cooled fast reactor ceramic main pump impeller device, characterized in that: The detachable impurity filtering and adsorption type lead-cooled fast reactor ceramic main pump impeller device comprises a ceramic impeller (1), a supporting pressure plate (2), a double-tower metal rubber component (3), a screw-in end cover (4), a suction end cover (6), an axial flow pump housing (7), a transmission shaft (8), a protective bracket (9), a rotating motor (10), a coupling (11) and a bearing cover (12); The ceramic impeller (1) is provided with a positioning hole in the axial direction for installing the transmission shaft (8), and the diameter of the tail end of the ceramic impeller (1) is larger than the diameter of the front end; the output end of the transmission shaft (8) is inserted into the positioning hole from the tail end of the ceramic impeller (1) and extends out of the positioning hole, and the tail end of the ceramic impeller (1) is connected to the shaft shoulder positioning part of the transmission shaft (8); the input end of the transmission shaft (8) is connected to the rotating motor (10) through a coupling (11), and a protective bracket (9) is provided on the outside of the transmission shaft (8), and openings are provided on both sides of the protective bracket (9) for the transmission shaft (8) to pass through; The supporting pressure plate (2) and the double-tower metal rubber assembly (3) are installed on the transmission shaft (8), located on the outside of the front end of the ceramic impeller (1), and fit together. The supporting pressure plate (2) is located between the double-tower metal rubber assembly (3) and the ceramic impeller (1); the front end of the transmission shaft (8) is provided with a thread, and the inner wall of the screw-in end cover (4) is provided with a screw-in thread (5). The screw-in thread (5) cooperates with the thread on the front end of the transmission shaft (8). The screw-in end cover (4) is installed on the front end of the transmission shaft (8) and presses the double-tower metal rubber assembly (3); The ceramic impeller (1), the supporting pressure plate (2), the double-tower metal rubber assembly (3), the screw-in end cover (4) and the front end of the transmission shaft (8) are located inside the axial flow pump housing (7); one side of the axial flow pump housing (7) is provided with an opening for the transmission shaft (8) to pass through; one side of the protective bracket (9) provided with the opening is fixedly connected to the side of the axial flow pump housing (7) provided with the opening, and the other side and the top opposite to each other are open structures, the top opening is used for connection and installation with other external devices, and the opening on the other side is installed with a suction end cover (6); the other side of the protective bracket (9) provided with the opening is provided with a bearing cover (12) to achieve sealing.

2. The detachable impurity filtering and adsorption type lead-cooled fast reactor ceramic main pump impeller device according to claim 1, characterized in that: The supporting pressure plate (2) is a disc structure, the inner wall of which is in contact with the transmission shaft (8), one side of the supporting pressure plate (2) is in contact with the front end of the ceramic impeller (1), and the other side is in contact with the double-tower metal rubber component (3).

3. The detachable impurity filtering and adsorption type lead-cooled fast reactor ceramic main pump impeller device according to claim 1, characterized in that: The double-tower metal rubber component (3) is a left-right symmetrical tower structure, and the left and right parts are both horizontally placed frustums, and the diameters of the left and right outer end faces are smaller than the diameter of the end face of the central axis part. The double-tower metal rubber component (3) is provided with a through opening along the horizontal central axis for the transmission shaft (8) to pass through.

4. The detachable impurity filtering and adsorption type lead-cooled fast reactor ceramic main pump impeller device according to claim 1, characterized in that: The suction end cover (6) is a disc structure, and a plurality of spiral diverter blades (13) are symmetrically arranged inside the suction end cover. One end of the spiral diverter blade (13) is fixed to the inner wall of the suction end cover (6), and the other end is fixed to the outer periphery of the central supporting circular plate of the suction end cover (6). A plurality of spiral flow guides are provided on the surface of the spiral diverter blade (13).

5. The detachable impurity filtering and adsorption type lead-cooled fast reactor ceramic main pump impeller device according to claim 1, characterized in that: The double-tower metal rubber component (3) is made of stainless steel wire with a diameter of 0.1-0.3 mm through winding, braiding and cold processing processes.

6. The detachable impurity filtering and adsorption type lead-cooled fast reactor ceramic main pump impeller device according to claim 1, characterized in that: The ceramic impeller (1) is formed by integrally sintering Max phase ceramic material.

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