High-efficiency energy-saving nuclear power condensate pump

Abstract

The application discloses a high-efficiency energy-saving nuclear power condensate pump, and relates to the technical field of pumps, which comprises a pump shell, an inner cylinder is inserted into the pump shell, the top of the inner cylinder is fixedly connected with the top of the pump shell, a drainage shell is fixedly installed on the top of the pump shell, a water pumping assembly is arranged in the inner cylinder, and the application further comprises a gas-liquid separation cylinder which is inserted between the inner cylinder and the pump shell, a water inlet pipe which is in communication with the gas-liquid separation cylinder is fixedly installed on the pump shell, and water in the gas-liquid separation cylinder flows downward in a spiral manner through the water inlet pipe. The micro-bubbles in water are removed in advance through the cyclone enrichment and the negative pressure one-way air permeation and degassing, the cavitation of the impeller and the efficiency attenuation of the pump body are inhibited from the root, the water inlet rotation direction is matched with the rotation direction of the impeller through the double-path pre-rotation structure, the turbulence and vortex loss are eliminated, the flow field is optimized, and the hydraulic efficiency and the energy-saving effect are improved.

Description

Technical Field

[0001] This invention belongs to the field of pump technology, specifically, it relates to a high-efficiency and energy-saving nuclear power plant condensate pump. Background Technology

[0002] The suction side of the condensate pump in nuclear power plants is a high-vacuum environment, where free air bubbles are easily generated in the water. These bubbles can cause cavitation damage, excessive vibration, and reduced operating efficiency when they enter the impeller. Therefore, the equipment has extremely high requirements for cavitation resistance, long service life, and vibration reduction performance.

[0003] For example, the patent document with announcement number CN102116319B discloses a condensate pump for nuclear power plants, including an outer cylinder, a pump body, an outlet shell, a motor frame, a pump shaft, a first-stage impeller, a second-stage impeller, a last-stage impeller, a mechanical seal, a bearing assembly, and a motor. The motor frame is fixed to the upper end of the outlet shell; the mechanical seal is located in the inner cavity of the outlet shell through a sealing shell; the bearing assembly includes several guide bearings and a vertical thrust bearing; the motor is fixed to the upper end of the motor frame and connected to the upper end of the pump shaft; the pump body includes a double-suction volute housing, a straight pipe, a secondary guide vane, and a final guide vane, which are coaxially connected to each other from bottom to top in the center of the inner cavity of the outer cylinder; the outlet shell is fixed to the upper end of the outer cylinder and connected to the final guide vane; a flange is installed on the outer circumference of the top plate of the straight pipe, and the flange is connected to the bottom plate of the outlet shell by several radially evenly distributed through rods and nuts to tighten the secondary guide vane and the final guide vane; an auxiliary support device is also provided between the pump body and the outer cylinder.

[0004] The above-mentioned pump body has many functional limitations during use: the water flow can only enter the double-suction volute directly through the inlet horn, and it is impossible to complete the directional bubble enrichment and negative pressure removal before the medium reaches the first-stage impeller, making it difficult to suppress impeller cavitation erosion and pump efficiency decline from the source; relying solely on the bottom single spring support for vibration reduction and thermal expansion compensation, it is impossible to construct an upper and lower stage coordinated vibration reduction system. In view of the above problems, a high-efficiency and energy-saving nuclear power condensate pump is proposed here. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-efficiency and energy-saving nuclear power plant condensate pump that can overcome or at least partially solve the above problems.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows: A high-efficiency and energy-saving nuclear power plant condensate pump includes a pump casing with an inner cylinder inserted into it. The top of the inner cylinder is fixedly connected to the top of the pump casing. A drainage shell is fixedly installed on the top of the pump casing. A pumping assembly is disposed in the inner cylinder. The pump also includes: a gas-liquid separator inserted between the inner cylinder and the pump casing; an inlet pipe fixedly installed on the pump casing, communicating with the gas-liquid separator; water entering the gas-liquid separator through the inlet pipe flows spirally downwards; a negative pressure chamber is provided between the gas-liquid separator and the pump casing, with a waterproof and breathable structure between them; a negative pressure suction pipe fixedly installed on the drainage shell, communicating with the negative pressure chamber; a bottom guide shroud snapped into the pump casing and fixed to the bottom of the inner cylinder, with its top snapped and sealed to the gas-liquid separator; the spirally downward flowing water is guided by the bottom guide shroud to flow spirally upwards, with the flow direction consistent with the rotation direction of the pumping assembly; and a damping and shock-absorbing assembly disposed at the bottom of the bottom guide shroud to absorb the impact load of the water flow on the bottom guide shroud.

[0007] Preferably, the inner cylinder includes, from top to bottom, a reducing guide tube, a final guide vane, two secondary guide vanes, a double-suction volute housing, and a horn frame, which are fixedly installed in sequence. The horn frame is fixedly connected to the double-suction volute housing, the top of the reducing guide tube is fixedly connected to the drainage housing, and a motor frame is fixedly installed on the top of the drainage housing.

[0008] Preferably, the pumping assembly includes a first-stage double-suction impeller disposed in a double-suction volute housing, a second-stage impeller disposed in a second-stage guide vane, a final-stage impeller disposed in a final-stage guide vane, and a rotating shaft disposed in an inner cylinder. The two ends of the rotating shaft are rotatably mounted to a motor frame and a horn frame, respectively. The first-stage double-suction impeller, the second-stage impeller, and the final-stage impeller are all fixedly connected to the rotating shaft. A limiting frame is fixedly installed inside the reducing guide tube. The limiting frame is rotatably connected to the rotating shaft. A balancing drum is fixedly fitted on the rotating shaft. The balancing drum is located inside the inner cavity of the drainage housing.

[0009] Preferably, the gas-liquid separator includes a first mounting cylinder and a second mounting cylinder arranged coaxially. The first mounting cylinder and the second mounting cylinder are fixedly installed by a spiral guide plate. The negative pressure chamber is located between the first mounting cylinder and the pump casing. The second mounting cylinder is inserted and fixedly connected to the bottom guide cover. A waterproof and breathable spiral wall is provided on the side wall of the first mounting cylinder. An mounting plate is fixedly installed on the top of the first mounting cylinder and the second mounting cylinder. A waterproof and breathable plate is fixedly installed on the mounting plate.

[0010] Preferably, the mounting cavity between the second mounting cylinder and the first mounting cylinder is wider at the top and narrower at the bottom, the second mounting cylinder is provided with an upper water inlet hole at the diameter change point of the mounting cavity, and a first guide vane is fixedly installed on the inner side of the second mounting cylinder; The first guide vane guides the water flow that is diverted into the second mounting cylinder from the mounting cavity to flow in a spiral manner to the water inlet above the double-suction volute housing, and the rotation direction of the water flow is consistent with the rotation direction of the first-stage double-suction impeller.

[0011] Preferably, the bottom guide shield includes a hemispherical shell, which is snapped and sealed to the first mounting cylinder and fixed. A conical guide column is fixedly installed at the center of the interior of the hemispherical shell, and a second guide vane is fixedly installed on the side wall of the conical guide column. An annular concave arc-shaped water guide slope is provided between the conical guide column and the hemispherical shell, and the conical guide column is coupled to the horn frame.

[0012] Preferably, a guide ring is fixedly installed at the bottom of the second mounting cylinder. The guide ring, in conjunction with the arc-shaped inner wall of the hemispherical shell, guides the spiral water flow discharged from the gas-liquid separator to the annular concave arc-shaped water guide slope. The annular concave arc-shaped water guide slope guides the water flow through the second guide vane. The second guide vane guides the water flow to spiral upward along the rotation direction of the first-stage double suction impeller.

[0013] Preferably, the negative pressure chamber is provided with an elastic element, which is fitted onto the outside of the inner cylinder. The two ends of the elastic element abut against and limit the mounting plate and the inner wall of the top of the pump casing, respectively. After the water pump is assembled, the elastic element is in a compressed and pre-tightened state.

[0014] Preferably, an elastic metal plug is fixedly installed inside the pump casing, the hemispherical shell is inserted into the elastic metal plug, and a sealing ring is fixedly installed inside the pump casing, the sealing ring abutting against the hemispherical shell for sealing.

[0015] Preferably, the damping shock absorption assembly includes a sling fixedly installed at the bottom of the hemispherical shell, a counterweight fixedly installed at the bottom of the sling, a sealed cavity provided inside the pump casing and below the hemispherical shell, the sealed cavity being filled with a damping medium, and the counterweight being immersed in the damping medium.

[0016] The present invention has at least the following beneficial effects: This invention uses swirl enrichment combined with negative pressure unidirectional ventilation and degassing to remove microbubbles in water in advance, thereby inhibiting impeller cavitation and pump efficiency decay from the source. The dual-path pre-swirl structure matches the inlet water swirl direction with the impeller rotation direction, eliminating turbulence and eddy current losses, optimizing the flow field, improving hydraulic efficiency and energy saving. The gap decoupling assembly can isolate the vibration on the inlet side, and the damping components can efficiently dissipate water hammer and vibration energy, resulting in excellent vibration reduction and noise reduction. Meanwhile, the controllable micro-vibration of the structure can assist in gas evolution and self-cleaning of dirt, effectively preventing flow channel blockage and reducing operation and maintenance costs; The multi-layered nested cylinder enhances the overall rigidity and pressure-bearing capacity of the machine, while the negative pressure interlayer reduces operating noise. With the combination of multi-stage booster rectification, axial balancing of the balance drum, and multi-point support structure, the rotor movement is effectively suppressed, ensuring long-term stable, high-precision, and reliable operation of the pump body, meeting the requirements of nuclear power for long-term maintenance-free, low-energy consumption, and high safety.

[0017] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0018] In the attached diagram: Figure 1 This is a three-dimensional structural diagram of a high-efficiency and energy-saving nuclear power plant condensate pump proposed in this invention; Figure 2 This is a front sectional view of a high-efficiency and energy-saving nuclear power plant condensate pump proposed in this invention; Figure 3 This is a schematic diagram of the gas-liquid separation cylinder of a high-efficiency and energy-saving nuclear power plant condensate pump proposed in this invention; Figure 4 for Figure 3 Schematic diagram of the structure at point A; Figure 5 This is a schematic diagram of the pumping assembly of a high-efficiency and energy-saving nuclear power plant condensate pump proposed in this invention; Figure 6 for Figure 5 Schematic diagram of the structure at point B; Figure 7 This is a schematic diagram of the inner cylinder of a high-efficiency and energy-saving nuclear power plant condensate pump proposed in this invention; Figure 8 This is a schematic diagram of the structure of a double-suction volute casing for a high-efficiency and energy-saving nuclear power condensate pump proposed in this invention. Figure 9 This is a schematic diagram of the bottom guide shield of a high-efficiency and energy-saving nuclear power condensate pump proposed in this invention.

[0019] In the diagram: 1. Pump casing; 2. Gas-liquid separator; 21. First mounting cylinder; 211. Waterproof and breathable spiral wall; 22. Second mounting cylinder; 221. Guide ring; 222. Upper water inlet; 223. First guide vane; 23. Spiral guide plate; 3. Pumping assembly; 31. Shaft; 32. First-stage double-suction impeller; 33. Second-stage impeller; 34. Final-stage impeller; 35. Limiting bracket; 4. Inner cylinder; 41. Double-suction volute casing; 42. Secondary guide vane; 43. Final-stage guide vane; 44. Reducer 45. Conduit; 46. Drainage shell; 47. Inlet pipe; 58. Horn bracket; 59. Bottom guide shield; 50. Hemispherical shell; 51. Second guide vane; 52. Annular concave arc-shaped water guide slope; 53. Conical guide column; 64. Negative pressure chamber; 65. Mounting plate; 66. Waterproof and breathable plate; 67. Negative pressure extraction pipe; 78. Sealing ring; 79. Elastic metal insert; 70. Elastic element; 81. Sealing chamber; 82. Sling; 83. Counterweight; 84. Damping medium; 95. Motor frame; 96. Balance drum. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0021] Example: Refer to Figures 1-9 A high-efficiency and energy-saving nuclear power plant condensate pump includes a pump casing 1, an inner cylinder 4 inserted into the pump casing 1, the top of the inner cylinder 4 being fixedly connected to the top of the pump casing 1, a drain casing 45 fixedly installed on the top of the pump casing 1, and a pumping assembly 3 disposed in the inner cylinder 4. It also includes a gas-liquid separator 2 inserted between the inner cylinder 4 and the pump casing 1, an inlet pipe 46 fixedly installed on the pump casing 1 communicating with the gas-liquid separator 2, and water entering the gas-liquid separator 2 through the inlet pipe 46 flowing spirally downwards; a negative pressure chamber 6 is provided between the gas-liquid separator 2 and the pump casing 1. A waterproof and breathable structure is provided between the gas-liquid separator 2 and the negative pressure chamber 6. A negative pressure suction pipe 63 connected to the negative pressure chamber 6 is fixedly installed on the drainage shell 45. The bottom guide shroud 5 is snapped into the pump shell 1 and fixed to the bottom of the inner cylinder 4. The top of the shroud is snapped and sealed to the gas-liquid separator 2. The water flowing downward spirally is guided by the bottom guide shroud 5 to change to flowing upward spirally, and the flow direction is consistent with the rotation direction of the pumping assembly 3. The damping and shock absorption assembly is set at the bottom of the bottom guide shroud 5 to absorb the impact load of the water flow on the bottom guide shroud 5.

[0022] This embodiment precisely addresses the technical shortcomings of traditional nuclear power plant condensate pumps by achieving overall matching and coordination of the pump casing 1, inner cylinder 4, gas-liquid separation cylinder 2, negative pressure chamber 6, bottom guide shroud 5, water pumping assembly 3, damping and shock absorption assembly, water inlet pipe 46, negative pressure extraction pipe 63, and waterproof and breathable structure. These shortcomings include cavitation during water inlet, lack of bubble pretreatment, limited vibration damping methods, lack of self-cleaning capability, easy clogging of flow channels, lack of negative pressure backflow prevention, lack of noise reduction and pressure-bearing structure, and a single water inlet flow field. The specific working principle is as follows: During operation, the condensate medium is first transported to the gas-liquid separator 2 through the inlet pipe 46. Under the guidance of the gas-liquid separator 2, the medium forms a stable spiral downward flow state. The centrifugal effect of the swirling flow causes the microbubbles and free gas carried in the water to accumulate on the cylinder wall, realizing the pretreatment of inlet bubbles. The gas-liquid separator 2 and the outer pump casing 1 enclose a negative pressure chamber 6. The operator continuously extracts air from the negative pressure chamber 6 through the negative pressure pipe 63 installed on the drain casing 45 to maintain a stable negative pressure environment inside the negative pressure chamber 6. With the waterproof and breathable structure set between the gas-liquid separator 2 and the negative pressure chamber 6, one-way separation of water and gas is realized. Only the accumulated gas is allowed to penetrate and overflow, while the water cannot leak out. Microbubbles and free gas in the water are continuously removed and discharged. Efficient gas-liquid separation is completed before the medium enters the pumping assembly 3, avoiding impeller cavitation erosion from the source and preventing the continuous decline of pump hydraulic efficiency.

[0023] During pump operation, the damping and vibration reduction components mounted at the bottom of the bottom guide shroud 5 continuously dissipate the vibration energy caused by water flow impact and the start-stop water hammer pulse load, replacing the traditional single spring vibration reduction structure and achieving a stable damping and vibration reduction effect. At the same time, the gas-liquid separation cylinder 2 and the bottom guide shroud 5 adopt a snap-fit ​​sealing assembly structure, which can retain a small amount of axial vibration margin. The small-amplitude micro-vibrations generated by the pump operation can continuously disturb the water flow, assisting the water microbubbles to be expelled and improving the gas-liquid separation effect. On the other hand, it can generate regular vibration pulses, which can shake off and clean the scale and fine impurities attached to the waterproof and breathable structure and internal flow channels in real time, realizing the active self-cleaning of the flow channels and preventing flow channel blockage.

[0024] After undergoing gas-liquid separation pretreatment, the spiral downward water flow completes a smooth flow channel reversal when passing through the bottom guide shroud 5, changing from spiral downward flow to spiral upward flow. Moreover, the overall rotation direction of the water flow is consistent with the rotation direction of the pumping assembly 3. This co-rotation structure completely changes the flow field defects of the traditional single direct-flow water inlet of the pump body, effectively eliminating inlet turbulence, flow deviation, and eddy impact phenomena. It allows the water flow to smoothly conform to the impeller blades inside the pumping assembly 3 and enter the pressurization area, significantly reducing hydraulic impact loss and ineffective eddy loss, optimizing the overall flow field state inside the pump, significantly improving the hydraulic utilization rate of the pump, and achieving a highly efficient and energy-saving operation effect.

[0025] The pump casing 1, gas-liquid separator 2 and inner cylinder 4 adopt a multi-layer nested assembly structure. The multi-layer cylinders constrain and limit each other, improving the overall structure's resistance to deformation and pressure stability. The negative pressure chamber 6 forms a sealed interlayer cavity, which can serve as a sound insulation buffer layer, effectively blocking the outward radiation of hydraulic turbulence noise and mechanical vibration noise inside the pump, significantly reducing the overall operating noise and optimizing the equipment's operating environment.

[0026] The gas-liquid separator 2 and the negative pressure chamber 6 form a stable internal and external pressure difference system. Relying on the waterproof and breathable structure's one-way barrier characteristic of only allowing air to pass through but not water, the negative pressure chamber 6 only extracts gas and does not form a water flow path. This can block the backflow of condensate through the branch of the negative pressure chamber 6, eliminating the need for additional auxiliary equipment such as shut-off valves and gas-water separators. This simplifies the overall structure of the pump body, reduces equipment failure points, and ensures long-term stable and continuous operation of the pump body.

[0027] Reference Figures 2-7 The inner cylinder 4 includes, from top to bottom, a reducing guide tube 44, a final stage guide vane 43, two secondary guide vanes 42, a double-suction volute housing 41, and a horn frame 47, which are fixedly installed in sequence. The horn frame 47 is fixedly connected to the double-suction volute housing 41. The top of the reducing guide tube 44 is fixedly connected to the drainage housing 45. A motor frame 9 is fixedly installed on the top of the drainage housing 45. The pumping assembly 3 includes a first-stage double-suction impeller 32 disposed in the double-suction volute housing 41 and a secondary impeller disposed in the secondary guide vanes 42. 33. The final stage impeller 34 is set in the final stage guide vane 43 and the rotating shaft 31 is set in the inner cylinder 4. The two ends of the rotating shaft 31 are rotatably installed with the motor frame 9 and the horn frame 47 respectively. The first stage double suction impeller 32, the secondary impeller 33 and the final stage impeller 34 are all fixedly connected to the rotating shaft 31. The limiting frame 35 is fixedly installed in the reducing guide tube 44. The limiting frame 35 is rotatably connected to the rotating shaft 31. The balancing drum 91 is fixedly mounted on the rotating shaft 31. The balancing drum 91 is located in the inner cavity of the drainage shell 45.

[0028] When the water pump is working, the motor mounted on the motor frame 9 drives the rotating shaft 31 to rotate. The rotating shaft 31 synchronously drives the first-stage double-suction impeller 32, the secondary impeller 33, and the final-stage impeller 34 to rotate at high speed. The co-current spiral water flow, which has been separated by gas-liquid separation and rectification at the front end, enters the double-suction volute casing 41, the secondary guide vane 42, and the final-stage guide vane 43 in sequence. Each stage of the impeller continuously performs work to pressurize the incoming condensate medium. The medium pressure is gradually increased through multi-stage segmented pressurization. At the same time, the guide vanes at each stage rectify and stabilize the high-speed water flow, regulate the flow field, and reduce turbulence and eddy current losses. After pressurization, the medium is stably discharged into the drainage casing 45 through the reducing pipe 44, realizing continuous and efficient pressurized delivery.

[0029] During the high-speed operation of the rotor, the pressure difference of the medium will generate a continuous axial thrust on each stage of the impeller, causing the shaft 31 to tend to move axially. At this time, the balance drum 91 arranged in the inner cavity of the drainage shell 45 uses the pressure difference formed by the high and low pressure chambers of the pump body to generate a reverse balance thrust, dynamically offsetting the axial load generated by the impeller, balancing the axial force on the shaft 31 in real time, effectively limiting the axial movement of the rotor. Together with the multi-point support structure formed by the motor frame 9, the horn frame 47 and the limit frame 35, it comprehensively ensures the long-term high-speed, stable and high-precision operation of the pumping assembly 3.

[0030] Reference Figures 2-6 and Figure 9 The gas-liquid separator 2 includes a first mounting cylinder 21 and a second mounting cylinder 22 coaxially arranged. The first mounting cylinder 21 and the second mounting cylinder 22 are fixedly installed by a spiral guide plate 23. The negative pressure chamber 6 is located between the first mounting cylinder 21 and the pump casing 1. The second mounting cylinder 22 is inserted and fixedly connected to the bottom guide cover 5. A waterproof and breathable spiral wall 211 is provided on the side wall of the first mounting cylinder 21. The top of the first mounting cylinder 21 and the second mounting cylinder 22 are fixedly installed with a mounting plate 61. A waterproof and breathable plate 62 is fixedly installed on the mounting plate 61. The mounting cavity between the second mounting cylinder 22 and the first mounting cylinder 21 is wider at the top and narrower at the bottom. The second mounting cylinder 22 is provided with an upper water inlet hole 222 at the diameter change of the mounting cavity. A first guide vane 223 is fixedly installed on the inner side of the second mounting cylinder 22. The first guide vane 223 guides the water flow into the inner side of the second mounting cylinder 22 in a spiral pattern. The water flows to the inlet above the double-suction volute housing 41, and the water flow rotation direction is consistent with the rotation direction of the first-stage double-suction impeller 32. The bottom guide shroud 5 includes a hemispherical housing 51, which is snapped and sealed to the first mounting cylinder 21. A conical guide column 54 is fixedly installed in the center of the interior of the hemispherical housing 51. A second guide vane 52 is fixedly installed on the side wall of the conical guide column 54. An annular concave arc-shaped water guide slope 53 is provided between the conical guide column 54 and the hemispherical housing 51. A guide ring 221 is fixedly installed at the bottom of the second mounting cylinder 22. The guide ring 221, in conjunction with the arc-shaped inner wall of the hemispherical housing 51, guides the spiral water flow discharged from the gas-liquid separator 2 to the annular concave arc-shaped water guide slope 53. The annular concave arc-shaped water guide slope 53 guides the water flow through the second guide vane 52. The second guide vane 52 guides the water flow to spiral upward along the rotation direction of the first-stage double-suction impeller 32.

[0031] Among them, the waterproof and breathable spiral wall 211 and the waterproof and breathable plate 62 are preferably made of polytetrafluoroethylene polymer breathable material or stainless steel powder sintered porous breathable material. This type of material has excellent characteristics such as high strength, corrosion resistance, high and low temperature resistance, uniform pore size, and air permeability without water permeability. It is suitable for the long-term operation of clean media in nuclear power plant condensate, and can effectively resist water vapor erosion and scaling blockage, ensuring that the breathable pores are unobstructed for a long time and that the gas-liquid separation performance is stable. At the same time, it has excellent anti-aging and anti-fatigue performance, meeting the requirements of long-term maintenance-free continuous operation of nuclear power equipment.

[0032] When the pump is working, condensate enters the mounting cavity between the first mounting cylinder 21 and the second mounting cylinder 22 through the inlet pipe 46, and then flows downward along the spiral guide plate 23. During the flow, the centrifugal effect of the swirling flow causes the tiny bubbles and free gas carried in the water to continuously accumulate and gather on the cylinder wall. The waterproof and breathable spiral wall 211 and the waterproof and breathable plate 62 form a double breathable structure on the side wall and top surface, allowing the accumulated gas to penetrate into the negative pressure chamber 6 in one direction and be continuously extracted. The water is completely blocked inside the chamber, achieving a continuous and stable negative pressure pre-gas-liquid separation effect.

[0033] The condensate, after gas-liquid separation, flows to the transition point of the mounting cavity (wider at the top and narrower at the bottom), forming two independent flow paths. These paths then flow through the bottom space of the mounting cavity and the upper inlet hole 222, respectively, to distribute the water. Part of the condensate is diverted through the upper water inlet 222 into the inner cavity of the second mounting cylinder 22. The incoming water flow is guided and regulated by the first guide vane 223 fixed inside the second mounting cylinder 22, so that the diverted water flow forms a stable spiral flow direction and is continuously transported to the water inlet area above the double suction volute 41. The rotation direction of this water flow is consistent with the rotation direction of the first-stage double suction impeller 32, realizing upper auxiliary pre-swirl water inlet. Most of the remaining condensate flows downward spirally along the bottom space of the installation cavity, forming the main inlet water flow. This water flow spirals downward and is guided by the annular concave arc-shaped water guide slope 53 and the waterproof and breathable spiral wall 211, thereby realizing the reversal of the water flow. The water flow that was originally flowing downward is reversed to flow upward. Under the secondary guidance of the second guide vane 52, the water flow is kept rotating and rising. The rotation direction of the water flow is consistent with the rotation direction of the first-stage double suction impeller 32.

[0034] During the overall operation, this structure eliminates air in the inlet water through multi-stage coordinated operation of spiral swirl air collection, negative pressure bidirectional permeable degassing, variable diameter upper and lower diversion water inlet, primary and secondary dual-path pre-swirl rectification, and bottom arc-shaped smooth reversal. This eliminates the drawbacks of turbulent flow field, large inlet water impact, and high eddy current loss, thereby suppressing impeller cavitation erosion and long-term pump efficiency decline from the root. It utilizes gravity, spiral guide plate 23, first guide vane 223, and second guide vane 52 to achieve water flow rotation, and the water flow rotation direction is precisely matched with the impeller working direction, which greatly reduces hydraulic ineffective loss and significantly improves the hydraulic utilization rate of the pump and the energy-saving operation effect of the whole machine.

[0035] Reference Figures 3-6 The negative pressure chamber 6 is equipped with an elastic element 72, which is fitted onto the outside of the inner cylinder 4. The two ends of the elastic element 72 abut against the mounting plate 61 and the inner wall of the top of the pump casing 1, respectively. After the water pump is assembled, the elastic element 72 is in a compressed and pre-tightened state. An elastic metal plug 71 is fixedly installed inside the pump casing 1. The hemispherical shell 51 is inserted into the elastic metal plug 71. A sealing ring 7 is fixedly installed inside the pump casing 1. The sealing ring 7 abuts against the hemispherical shell 51 and seals. The damping and shock absorption assembly includes a sling 81 fixedly installed at the bottom of the hemispherical shell 51. A counterweight 82 is fixedly installed at the bottom of the sling 81. A sealing chamber 8 is provided inside the pump casing 1 and below the hemispherical shell 51. The sealing chamber 8 is filled with a damping medium 83 (damping oil). The counterweight 82 is immersed in the damping medium 83.

[0036] When the pump body expands and contracts due to temperature rise during operation, or when parts experience slight axial movement, or when assembly gaps gradually widen due to vibration, the elastic element 72 automatically compensates for the gaps caused by dimensional changes by relying on its own expansion and contraction characteristics. This maintains the tight sealing state between the gas-liquid separator 2 and the bottom guide shroud 5 throughout the process, preventing gaps from appearing at the connection point. The negative pressure chamber 6 is enclosed by the gas-liquid separator 2 and the pump casing 1. The airtight seal prevents outside air from seeping into the negative pressure chamber 6 and also avoids leakage of negative pressure from the chamber. This stabilizes the negative pressure value inside the negative pressure chamber 6, ensuring that the waterproof and breathable spiral wall 211 and the waterproof and breathable plate 62 can properly exhaust air in one direction, and preventing the gas-liquid separation from failing due to insufficient negative pressure.

[0037] The elastic metal insert 71 itself has elastic deformation capability, which will not completely lock and fix the hemispherical shell 51, allowing the bottom guide shroud 5 to produce a very small range of vertical and radial micro-movements, that is, to reserve a small floating margin.

[0038] A sling 81 and a counterweight 82 are connected below the hemispherical shell 51. The counterweight 82 is immersed in the damping medium 83 of the sealed cavity 8. When the water flow impact and pump body vibration are transmitted to the hemispherical shell 51, the floating structure can produce a small sway. The counterweight 82 moves in the damping medium 83 with the sway, and the vibration impact energy is consumed by the viscous resistance of the liquid, thus completing the vibration reduction and noise reduction.

[0039] In this invention, the conical guide column 54 and the horn frame 47 are only coaxially nested, without rigid contact or fixed connection. The gas-liquid separation cylinder 2, the inner cylinder 4, and the pumping assembly 3 are completely decoupled from each other under force. The water flow impact and vibration on the inlet side will not be transmitted inward to the impeller system of the rotating shaft 31, and the rotor operation is more stable. The bottom guide cover 5 has a complete axial floating margin and can generate controllable small-amplitude micro-vibration by relying on the water flow impact. It can not only dissipate the impact energy with the help of the counterweight 82 and the damping medium 83 to achieve vibration reduction and noise reduction, but also shake off the dirt and impurities attached to the flow channel and the air-permeable structure through vibration, disturb the water body to accelerate the precipitation of bubbles, enhance the self-cleaning effect and the pre-gas-liquid separation effect, and is less likely to cause flow channel blockage.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-efficiency and energy-saving nuclear power plant condensate pump, comprising a pump casing (1), characterized in that, An inner cylinder (4) is inserted into the pump casing (1), the top of the inner cylinder (4) is fixedly connected to the top of the pump casing (1), a drain housing (45) is fixedly installed on the top of the pump casing (1), a pumping assembly (3) is provided in the inner cylinder (4), and the pumping assembly (3) is also provided. A gas-liquid separator (2) is inserted between the inner cylinder (4) and the pump casing (1). A water inlet pipe (46) communicating with the gas-liquid separator (2) is fixedly installed on the pump casing (1). Water entering the gas-liquid separator (2) through the water inlet pipe (46) flows downward in a spiral. A negative pressure chamber (6) is provided between the gas-liquid separation cylinder (2) and the pump casing (1). A waterproof and breathable structure is provided between the gas-liquid separation cylinder (2) and the negative pressure chamber (6). A negative pressure suction pipe (63) communicating with the negative pressure chamber (6) is fixedly installed on the drainage casing (45). The bottom guide shroud (5) is snapped into the pump housing (1) and fixed to the bottom of the inner cylinder (4), and the top is snapped and sealed with the gas-liquid separator (2). The water flowing downward spiral is guided by the bottom guide shroud (5) to change into flowing upward spiral, and the flow direction is consistent with the rotation direction of the pumping assembly (3). The damping and shock absorption component is set at the bottom of the bottom guide shield (5) to absorb the impact load of the water flow on the bottom guide shield (5).

2. The high-efficiency and energy-saving nuclear power plant condensate pump according to claim 1, characterized in that, The inner cylinder (4) includes a reducing guide tube (44), a final stage guide vane (43), two secondary guide vanes (42), a double-suction volute housing (41), and a horn frame (47) that are fixedly installed from top to bottom. The horn frame (47) is fixedly connected to the double-suction volute housing (41). The top of the reducing guide tube (44) is fixedly connected to the drainage housing (45). A motor frame (9) is fixedly installed on the top of the drainage housing (45).

3. The high-efficiency and energy-saving nuclear power plant condensate pump according to claim 2, characterized in that, The pumping assembly (3) includes a first-stage double-suction impeller (32) in the double-suction volute housing (41), a second-stage impeller (33) in the second-stage guide vane (42), a last-stage impeller (34) in the last-stage guide vane (43), and a rotating shaft (31) in the inner cylinder (4). The two ends of the rotating shaft (31) are rotatably installed with the motor frame (9) and the horn frame (47) respectively. The first-stage double-suction impeller (32), the second-stage impeller (33), and the last-stage impeller (34) are all fixedly connected to the rotating shaft (31). A limiting frame (35) is fixedly installed in the reducing guide tube (44). The limiting frame (35) is rotatably connected to the rotating shaft (31). A balancing drum (91) is fixedly mounted on the rotating shaft (31). The balancing drum (91) is located inside the inner cavity of the drainage housing (45).

4. A high-efficiency and energy-saving nuclear power plant condensate pump according to claim 3, characterized in that, The gas-liquid separation cylinder (2) includes a first mounting cylinder (21) and a second mounting cylinder (22) arranged coaxially. The first mounting cylinder (21) and the second mounting cylinder (22) are fixedly installed by a spiral guide plate (23). The negative pressure chamber (6) is located between the first mounting cylinder (21) and the pump casing (1). The second mounting cylinder (22) is inserted and fixedly connected to the bottom guide cover (5). A waterproof and breathable spiral wall (211) is provided on the side wall of the first mounting cylinder (21). An installation plate (61) is fixedly installed on the top of the first mounting cylinder (21) and the second mounting cylinder (22). A waterproof and breathable plate (62) is fixedly installed on the installation plate (61).

5. A high-efficiency and energy-saving nuclear power plant condensate pump according to claim 4, characterized in that, The mounting cavity between the second mounting cylinder (22) and the first mounting cylinder (21) is wider at the top and narrower at the bottom. The second mounting cylinder (22) has an upper water inlet hole (222) at the diameter change of the mounting cavity. The first guide vane (223) is fixedly installed on the inner side of the second mounting cylinder (22). The first guide vane (223) guides the water flow that is diverted into the second mounting cylinder (22) in the mounting cavity to flow in a spiral manner to the water inlet above the double suction volute housing (41), and the water flow rotation direction is consistent with the rotation direction of the first-stage double suction impeller (32).

6. A high-efficiency and energy-saving nuclear power plant condensate pump according to claim 4, characterized in that, The bottom guide shield (5) includes a hemispherical shell (51), which is snapped and sealed to the first mounting cylinder (21) and fixed. A conical guide column (54) is fixedly installed in the center of the interior of the hemispherical shell (51). A second guide vane (52) is fixedly installed on the side wall of the conical guide column (54). An annular concave arc-shaped water guide slope (53) is provided between the conical guide column (54) and the hemispherical shell (51). The conical guide column (54) is coupled to the horn frame (47).

7. A high-efficiency and energy-saving nuclear power plant condensate pump according to claim 6, characterized in that, A guide ring (221) is fixedly installed at the bottom of the second mounting cylinder (22). The guide ring (221) cooperates with the arc-shaped inner wall of the hemispherical shell (51) to guide the spiral water flow discharged from the gas-liquid separation cylinder (2) to the annular concave arc-shaped water guide slope (53). The annular concave arc-shaped water guide slope (53) guides the water flow through the second guide vane (52). The second guide vane (52) guides the water flow to spiral upward along the rotation direction of the first-stage double suction impeller (32).

8. A high-efficiency and energy-saving nuclear power plant condensate pump according to claim 6, characterized in that, The negative pressure chamber (6) is provided with an elastic element (72), which is fitted on the outside of the inner cylinder (4). The two ends of the elastic element (72) abut against and limit the mounting plate (61) and the top inner wall of the pump casing (1), respectively. After the water pump is assembled, the elastic element (72) is in a compressed and pre-tightened state.

9. A high-efficiency energy-saving nuclear power plant condensate pump according to claim 8, characterized in that, An elastic metal plug (71) is fixedly installed inside the pump casing (1), and the hemispherical shell (51) is inserted into the elastic metal plug (71). A sealing ring (7) is fixedly installed inside the pump casing (1), and the sealing ring (7) abuts against the hemispherical shell (51) for sealing.

10. A high-efficiency and energy-saving nuclear power plant condensate pump according to claim 6, characterized in that, The damping shock absorption assembly includes a sling (81) fixedly installed at the bottom of the hemispherical shell (51), a counterweight (82) fixedly installed at the bottom of the sling (81), a sealing cavity (8) is provided inside the pump casing (1) and below the hemispherical shell (51), the sealing cavity (8) is filled with a damping medium (83), and the counterweight (82) is immersed in the damping medium (83).

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