Blade-adjustable vertical metal seawater circulating pump for nuclear power station

Abstract

The invention discloses a blade-adjustable vertical metal seawater circulating pump for a nuclear power station, and relates to the technical field of seawater circulating pumps, the blade-adjustable vertical metal seawater circulating pump comprises a connecting pipe, a support, a pump shaft, a protective sleeve, a water lubricated bearing, a water outlet elbow, a motor, a guide blade body, an impeller chamber, a suction horn and an impeller body, and a filler sealing component is arranged between the water outlet elbow and the pump shaft; the impeller body is composed of a hub and blade bodies, the blade bodies are evenly distributed on the outer surface of the hub in the circumferential direction, the impeller body adjusts the angles of the blade bodies through hydraulic oil, the pump set is of a core-pulling structure, and under the condition that a suction horn, a connecting pipe and a water outlet bent pipe are not disassembled, only the rotor part of the pump needs to be pulled out, the rotor part can be overhauled; the hydraulic adjusting mechanism is arranged, online real-time blade angle adjustment is supported, working condition changes can be responded without shutdown, system operation flexibility and control precision are improved, and safe, stable and efficient operation of the nuclear power station cooling water system is guaranteed.

Description

Technical Field

[0001] This application relates to the field of seawater circulation pump technology, and in particular to an adjustable blade vertical metal seawater circulation pump for use in nuclear power plants. Background Technology

[0002] The vertical adjustable blade metal seawater circulating pump used in nuclear power plants is a key piece of equipment in the nuclear island circulating water system. Its operational reliability is directly related to the safety and efficiency of the power plant. The function of the circulating water system is to provide the necessary cooling water to the condenser of the steam turbine and the heat exchangers of the auxiliary cooling water system in the conventional island during unit operation.

[0003] Currently, the adjustable blade vertical metal seawater circulation pumps used in nuclear power plants have relatively complex blade adjustment mechanisms with some structures exposed. This not only increases the overall size of the equipment but also makes them susceptible to seawater corrosion and external environmental factors. Furthermore, some adjustment mechanisms are not direct and efficient enough in the transmission process when adjusting the blade angle, resulting in energy loss and slow adjustment response. As a result, they cannot meet the stringent requirements of nuclear power plants for efficient and precise adjustment of seawater circulation pumps. Summary of the Invention

[0004] To address the issue of external hydraulic cylinder adjusting blades being susceptible to external influences, leading to indirect transmission, this application provides an adjustable blade vertical metal seawater circulation pump for nuclear power plants.

[0005] This application provides a technical solution for an adjustable-blade vertical metal seawater circulating pump used in nuclear power plants, which adopts the following approach: An adjustable-blade vertical metal seawater circulating pump for nuclear power plants includes a connecting pipe and a support. A pump shaft runs through the inside of the connecting pipe, and a protective sleeve is installed at the top of the connecting pipe. A water-lubricated bearing is installed inside the protective sleeve, and a water outlet bend is installed at the top of the protective sleeve. A motor is installed inside the support, and the output shaft of the motor is connected to the pump shaft via a coupling. A packing seal is installed between the water outlet bend and the pump shaft. A guide vane is installed at the bottom of the connecting pipe, and an impeller chamber is installed inside the guide vane. A suction horn is installed at the bottom of the guide vane, and an impeller body is installed inside the impeller chamber. The impeller body is a mixed-flow impeller body, consisting of a hub and blades. The blades are evenly distributed around the outer surface of the hub, and the angle of the blades is adjusted by hydraulic oil. The pump set adopts a removable core structure, which can be removed simply by extracting the pump rotor without removing the suction horn, connecting pipe and discharge bend.

[0006] By adopting the above technical solution, the circulating pump is composed of core components such as connecting pipe, support, sheath, outlet bend, and motor into a vertical unit. The connecting pipe runs through the pump shaft, and the top is connected to the sheath and outlet bend in sequence. The bottom is connected to the suction horn via guide vanes, forming a complete flow channel. The support supports the motor at the top, which drives the pump shaft via a coupling. The impeller adopts a mixed-flow design, and its blade angle can be adjusted via a hydraulic system. Most importantly, the entire pump unit adopts a "removable core structure," meaning that during maintenance, it is not necessary to disassemble large components such as the suction horn, connecting pipe, and outlet bend. The fixed components only require the rotor assembly, including the impeller and pump shaft, to be extracted as a whole, which greatly shortens maintenance time and improves the economy and safety of nuclear power plant operation. In addition, the seawater circulating water pump adopts a single-stage single-suction, adjustable blade mixed-flow pump structure, which can flexibly adapt to different operating conditions and ensure that the system always operates stably near the high-efficiency zone, significantly improving energy utilization efficiency. It is also equipped with a hydraulic adjustment mechanism to support online real-time adjustment of blade angle, which can respond to changes in operating conditions without stopping the machine, improving the system's operational flexibility and control accuracy, and ensuring the safe, stable and efficient operation of the nuclear power plant's cooling water system.

[0007] Preferably, the output shaft of the motor and the pump shaft are rigidly connected. The coupling transmits the torque generated by the motor from the output shaft to the main shaft of the pump shaft and transmits the thrust of the pump to the thrust bearing at the top of the motor.

[0008] By adopting the above technical solution, a rigid coupling is used to connect the motor output shaft and the pump shaft. This connection method has a dual core function: first, it efficiently and reliably transmits the torque generated by the motor to the pump shaft to drive the impeller to rotate; second, it transmits the axial thrust generated during the operation of the water pump (such as the reaction force of the water and the weight of the rotor) to a special thrust bearing at the top of the motor through the coupling to bear it, thus ensuring the axial stable positioning of the entire rotor system.

[0009] Preferably, the suction horn is used to introduce water flow into the impeller body, and the suction horn is horn-shaped.

[0010] By adopting the above technical solution, the suction horn at the bottom of the pump body has a horn-shaped opening. Its main function is to guide the water flow smoothly into the impeller chamber. Its specific streamlined design can optimize the water intake conditions, effectively prevent the generation of harmful vortices and pressure pulsations, create a good inflow environment for the efficient and stable operation of the impeller, and improve the hydraulic performance of the pump from the source.

[0011] Preferably, the guide vane body is manufactured by casting, welding and CNC machining. The blades are cast from duplex stainless steel, and the outer and inner rings are welded to the blades. The guide vane body converts the velocity head of the medium at the blade outlet into pressure energy, collects the liquid flow, guides it through the connecting pipe to the water outlet bend, and then transports it to the water outlet pipe.

[0012] By adopting the above technical solution, the guide vane is located behind the impeller outlet and is made of duplex stainless steel using a casting and welding process. Its core function is to "rectify" and "convert energy" the high-speed water flow from the impeller: on the one hand, its blades guide the rotational motion of the water flow into axial motion; on the other hand, it effectively converts part of the kinetic energy (velocity head) of the water flow into pressure energy, thereby improving the pump efficiency and smoothly guiding the collected liquid flow into the connecting pipe.

[0013] Preferably, the water outlet bend is a guide component that changes the direction of water flow from vertical to horizontal, and its inner wall is smooth.

[0014] By adopting the above technical solution, the outlet bend is the final guiding component of the flow channel. Its function is to transform the vertical upward water flow that flows out of the protective pipe into a horizontal flow that flows out of the pump body through the smooth and gently transitioning internal flow channel. The excellent hydraulic profile design can minimize the local loss and disturbance when the water flow changes direction, ensure the smooth flow of the outlet water, and thus reduce the impact on the subsequent pipeline system.

[0015] Preferably, a flow guide is provided at the outlet of the sheath tube, the flow guide has a smooth streamline shape, and multiple reinforcing ribs are welded between the sheath tube and the flow guide.

[0016] By adopting the above technical solution, the sheath pipe is connected between the connecting pipe and the outlet bend. Its function is to form a diffusion section, so that the water flow velocity from the connecting pipe can be reduced evenly and gently, thereby converting some kinetic energy into pressure energy and reducing hydraulic losses along the way. The guide shroud and its reinforcing ribs at the outlet further optimize the flow pattern, ensuring that the water flow enters the bend smoothly. At the same time, the reinforcing ribs can withstand the water flow reaction force, enhance the structural rigidity, and suppress vibration.

[0017] Preferably, the water-lubricated bearing is a guide bearing made of polymer material. The guide bearing allows the spindle to move axially within the guide bearing. The guide bearing and its support have sufficient strength and rigidity to withstand the maximum radial load to avoid harmful vibration. Each bearing has an independent flushing water pipe.

[0018] By adopting the above technical solution, the water-lubricated bearing is installed inside the protective sleeve to support the pump shaft. It is a guide bearing made of polymer material, which allows the pump shaft to have a certain degree of axial movement freedom when rotating. Its function is to provide reliable radial support for the long shaft system, withstand the radial load generated by water flow and rotor, prevent harmful vibration, and the independent flushing water pipeline can continuously clean the bearing. Its sealing and sand removal functions ensure the reliability and durability of operation in sandy seawater.

[0019] Preferably, an adjusting arm is provided on one side of the blade body, and the adjusting arm is located inside the blade body. The pump shaft is disposed inside the hub. The pump shaft is provided with two cylinders for adjusting hydraulic oil. A cylinder is fixed on the outer surface of the pump shaft. A piston rod is slidably disposed inside the cylinder. The piston rod is slidably disposed inside the cylinder. A connecting rod is rotatably connected to the outer ring of the piston rod. The connecting rod is rotatably connected to the adjusting arm. The piston rod moves up and down to drive the connecting rod to rotate the blade body clockwise or counterclockwise. A buffer device is provided on the inner wall of the hub.

[0020] By adopting the above technical solution, this is the core actuator for blade angle adjustment. The adjusting arm is located inside the blade and connected to it. The pump shaft integrates a control cylinder. Its working process is as follows: hydraulic oil drives cylinder one or cylinder two to move, pushing the piston rod to make precise linear motion inside the fixed cylinder; the piston rod converts the linear motion into the rotational motion of the adjusting arm through a linkage mechanism (such as a ball joint), thereby driving all blades to rotate synchronously and precisely around their axis, realizing stepless adjustment of pump performance. The buffer device set in the hub is used to improve the smoothness of this process.

[0021] Preferably, the buffer device includes a fixed cylinder fixed inside the hub, a movable column rotatably connected to the fixed cylinder on the outer surface of the adjusting arm, a damper for absorbing and dissipating the impact energy of the blades by external forces fixedly connected between the movable column and the inner wall of the fixed cylinder, and a return spring fixedly connected between the movable column and the inner wall of the fixed cylinder, the return spring being sleeved on the outer surface of the damper to allow the movable column to return to its initial position after being impacted.

[0022] By adopting the above technical solution, the buffer device consists of a fixed cylinder, a moving column, a damper, and a return spring. Its specific function is as follows: when the blade is adjusted or impacted by water flow, the moving column connected to the adjusting arm slides in the fixed cylinder, and the damper can immediately absorb and dissipate the impact energy, effectively suppressing vibration and preventing hard impacts; the return spring provides restoring force, assisting the moving column and adjusting mechanism to quickly and stably return to the predetermined position after the impact or when the action ends, thereby protecting the adjusting mechanism, extending its service life, and ensuring the setting accuracy of the blade angle.

[0023] Preferably, the bracket is a welded structure made of carbon structural steel and coated with anti-corrosion paint. The design of the bracket is determined according to the requirements of the water pump layout and motor connection, and the dimensions are accurately matched with the motor to ensure correct connection.

[0024] By adopting the above technical solution, the bracket is the basic support structure connecting the pump body and the motor. It is made of carbon steel structure welded and treated with anti-corrosion. Its function is to provide a support platform with sufficient strength and rigidity according to the arrangement requirements of the water pump and the motor, so as to ensure that the motor and the water pump shaft system are accurately aligned and connected. The stable bracket is an important foundation for ensuring the long-term stable and fault-free operation of the entire pump set.

[0025] In summary, this application includes at least one of the following beneficial technical effects: 1. The seawater circulating pump in this application adopts a retractable vertical design, which is compact in structure, easy to maintain and repair, and significantly reduces downtime and maintenance costs. Furthermore, the seawater circulating pump uses a single-stage, single-suction, adjustable-blade mixed-flow pump structure, which can flexibly adapt to different operating conditions, ensuring that the system always operates stably near the high-efficiency zone, and significantly improving energy utilization efficiency. 2. Key components in contact with seawater are made of duplex steel, which has excellent corrosion resistance and cavitation resistance, effectively extending the service life of the pump unit and reducing the total life cycle cost; equipped with a hydraulic adjustment mechanism, it supports online real-time adjustment of the blade angle, which can respond to changes in operating conditions without stopping the machine, improving the system's operational flexibility and control accuracy, and ensuring the safe, stable and efficient operation of the nuclear power plant's cooling water system.

[0026] 3. By using a buffer device installed on the inner wall of the hub, when the blades are impacted by external forces during adjustment or operation, the moving column slides in the fixed cylinder, the damper absorbs and dissipates the impact energy, and the return spring restores the moving column to its initial position, thereby effectively buffering the impact of external forces on the blades and hub, reducing vibration and stress concentration, improving the stability and reliability of pump unit operation, and extending the service life of the equipment. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of this application; Figure 2 This is a partial structural diagram of this application; Figure 3 This is a schematic diagram of the internal structure of the impeller body in this application; Figure 4 This is a schematic diagram of the internal structure of the cylinder in this application; Figure 5 This is a schematic diagram of the internal structure of the fixed cylinder in this application.

[0028] Reference numerals: 1. Suction horn; 2. Impeller chamber; 3. Guide vane; 4. Impeller body; 41. Hub; 42. Blade body; 43. Adjusting arm; 5. Pump shaft; 51. Cylinder; 52. Piston rod; 53. Connecting rod; 54. Cylinder 1; 55. Cylinder 2; 56. Fixed cylinder; 57. Moving column; 58. Return spring; 59. Damper; 6. Connecting pipe; 7. Sheath pipe; 8. Water-lubricated bearing; 9. Water outlet bend; 10. Packing seal component; 11. Coupling; 12. Bracket; 13. Motor. Detailed Implementation

[0029] The following is in conjunction with the appendix Figures 1-5 This application will be described in further detail.

[0030] Example 1 This application discloses an adjustable blade vertical metal seawater circulation pump for use in nuclear power plants.

[0031] Reference Figure 1 An adjustable blade vertical metal seawater circulating pump for nuclear power plants includes a connecting pipe 6 and a support 12. The support 12 is a welded structure made of carbon structural steel and coated with anti-corrosion paint. The design of the support 12 is determined according to the requirements of the pump layout and motor connection. Its dimensions are accurately aligned with the motor 13 to ensure correct connection. A pump shaft 5 is fixedly connected through the inside of the connecting pipe 6. The pump shaft 5 is a hollow shaft design. A protective sleeve 7 is fixedly connected and connected to the top surface of the connecting pipe 6. A flow guide is installed at the outlet of the protective sleeve 7. The flow guide has smooth flow lines to minimize local hydraulic loss and ensure stable outflow. Multiple reinforcing ribs are welded between the protective sleeve 7 and the flow guide to withstand the outlet dynamic reaction force and reduce vibration and sway caused by water flow disturbance. The sheath tube 7 has a water-lubricated bearing 8 that is slidably connected inside. The water-lubricated bearing 8 is a guide bearing made of polymer material. The guide bearing allows the spindle to move axially within the guide bearing. The guide bearing and its support have sufficient strength and rigidity to withstand the maximum radial load to avoid harmful vibration. Each bearing has an independent flushing water pipe with sealing and mud and sand discharge functions to ensure that the guide bearing is not worn by mud and sand. The top of the protective sleeve 7 is fixedly connected to and connected to the outlet bend 9. The outlet bend 9 is a guide component that changes the direction of water flow from vertical to horizontal. Its inner wall is smooth and, together with the flow guide cover of the protective sleeve 7, the transition is uniform and smooth, and the hydraulic performance is good. The fixed section of the motor 13 is fixedly connected inside the bracket 12. The motor 13 adopts a large vertical squirrel cage asynchronous motor 13. The thrust bearing of the motor 13 bears the thrust of the entire seawater circulating water pump group. The motor 13 can adopt a variable frequency or fixed frequency operation mode. The output shaft of the motor 13 is connected to the main shaft of the pump shaft 5 with high-strength bolts. The coupling 11 transmits the torque generated by the motor 13 from the output shaft of the motor 13 to the main shaft of the pump shaft 5, and transmits the thrust of the pump to the thrust bearing at the top of the motor 13. A packing seal component 10 is provided between the outlet elbow 9 and the pump shaft 5. The packing is pressed into the stuffing box by the gland to achieve a sealing effect. The packing seal has the characteristics of tight sealing, wear resistance, simple and reliable structure, and easy maintenance and replacement. The packing packing is made of composite material braiding, with excellent self-lubricating performance. The cooling and lubrication water during operation is provided from the outside. The packing seal component 10 can be made of graphite-reinforced polytetrafluoroethylene packing. The bottom of the connecting pipe 6 is fixedly connected to and connected to the guide vane body 3. The guide vane body 3 is made by casting, welding and CNC machining. The blades are made of duplex stainless steel. The outer ring and inner ring are welded to the blades. The guide vane body 3 converts the medium velocity head at the blade outlet into pressure energy, collects the liquid flow, guides it through the connecting pipe 6 to the water outlet bend 9, and transports it to the water outlet pipe. The inner wall of the guide vane body 3 is fixedly connected to the impeller chamber 2, and the bottom of the guide vane body 3 is fixedly connected to the suction horn 1. The suction horn 1 is used to introduce water flow into the impeller body 4, and the suction horn 1 is horn-shaped. The shape and size of the horn-shaped water inlet have good hydraulic characteristics and do not produce harmful vortices and pressure pulsations. The impeller body 4 is installed inside the impeller chamber 2. The impeller body 4 is a mixed flow impeller body 4. The impeller body 4 is composed of a hub 41 and blade body 42. The blade body 42 is evenly distributed on the outer surface of the hub 41. The impeller body 4 adjusts the angle of its blade body 42 by hydraulic oil. The pump set adopts a core-pulling structure. Without removing the suction horn 1, connecting pipe 6 and outlet bend 9, the rotor component of the pump can be pulled out for maintenance, saving maintenance time to the greatest extent.

[0032] Before the pump unit is started, the thrust bearing of the motor 13 has already borne the weight of the entire rotating part and the water thrust. After starting, the motor 13 transmits the torque to the pump shaft 5 through the coupling 11, driving the impeller body 4 to rotate at high speed. The water flow is smoothly introduced through the horn-shaped suction horn 1, effectively avoiding harmful vortices and pressure pulsations. After entering the impeller chamber 2, the water flow impacts the blade body 42 of the mixed flow impeller body 4, and the impeller body 4 converts mechanical energy into the kinetic energy and pressure energy of the water. The high-speed water flow from the impeller body 4 enters the guide vane body 3. The duplex stainless steel blades of the guide vane body 3 orderly convert the rotational kinetic energy of the water flow into pressure energy and guide the collected liquid flow to the connecting pipe 6. Subsequently, the water flow enters the sheath pipe 7 through the connecting pipe 6. The sheath pipe 7, with its good hydraulic profile, reduces the flow velocity evenly and gently, reducing friction loss. The guide shroud and reinforcing rib structure at its outlet further ensures smooth water flow direction and resists dynamic reaction force, reducing vibration. The water then enters the outlet bend 9, where it undergoes a smooth transition from vertical to horizontal, and finally flows smoothly into the outlet pipe. Throughout this process, the pump shaft 5 is radially supported by the water-lubricated bearing 8, allowing axial movement. Its independent flushing system ensures the cleanliness and durability of the bearing. The packing seal component 10, lubricated by external cooling water, effectively prevents water leakage from the pump shaft 5. When a shutdown for maintenance is required, the advantages of its pull-out structure can be utilized: after disconnecting the coupling 11 between the motor 13 and the pump shaft 5, the entire rotor assembly, including the impeller body 4, guide vane body 3, pump shaft 5 and water-lubricated bearing 8, can be vertically extracted from the fixed housing composed of the suction horn 1, connecting pipe 6 and outlet bend 9, thereby greatly simplifying the maintenance process and saving critical time.

[0033] Example 2 Reference Figure 1 - Figure 5 An adjusting arm 43 is fixedly connected to one side of the blade body 42, and the adjusting arm 43 is located inside the blade body 42. The pump shaft 5 is installed inside the hub 41. The pump shaft 5 is fixedly connected to a first cylinder 54 and a second cylinder 55. The first cylinder 54 and the second cylinder 55 are used to adjust the hydraulic oil. A cylinder 51 is fixedly connected to the outer surface of the bottom end of the pump shaft 5. A piston rod 52 is slidably connected inside the cylinder 51, and the piston rod 52 is slidably connected inside the cylinder 51. A connecting rod 53 is rotatably connected to the outer circumference array of the piston rod 52. The connecting rod 53 is hinged to the adjusting arm 43 through a ball joint. The piston rod 52 moves up and down to drive the connecting rod 53 to make the blade body 42 rotate clockwise or counterclockwise. A buffer device is provided on the inner wall of the hub 41. The buffer device includes a fixed cylinder 56, which is symmetrically fixed to the top of the inner wall of the hub 41. A movable column 57 is rotatably connected to the outer surface of the adjusting arm 43. The movable column 57 is slidably connected to the inner wall of the fixed cylinder 56. A damper 59 is fixedly connected to the side of the movable column 57 near the fixed cylinder 56, and the other side of the damper 59 is fixedly connected to the inner wall of the fixed cylinder 56. The damper 59 is used to absorb and dissipate the impact energy of the blades from external forces. A return spring 58 is fixedly connected to the side of the movable column 57 near the fixed cylinder 56. The side of the return spring 58 away from the movable column 57 is fixedly connected to the inner wall of the fixed cylinder 56, and the return spring 58 is sleeved on the outer surface of the damper 59 to allow the movable column 57 to return to its initial position after being impacted.

[0034] When it is necessary to adjust the blade body angle 42 to adapt to changes in system operating conditions, the blade adjustment system starts working. According to the instructions, the external hydraulic control unit pumps the pressurized oil through the oil circuit inside the pump shaft 5 to the first cylinder 54 or the second cylinder 55 respectively. If it is necessary to increase the blade angle, such as by rotating counterclockwise, pressurized oil enters cylinder 54 to push the piston inside, or enters cylinder 55 from the other side to pull the piston. This piston movement directly drives the piston rod 52, which is rigidly connected to it, to move precisely axially along the inner wall of the cylinder 51 fixed on the pump shaft 5, for example, upward. The linear movement of the piston rod 52 is converted into rotational torque through multiple connecting rods 53 distributed in a circular array on its outer ring. The upper end of each connecting rod 53 is hinged to the piston rod 52 through a ball joint, and the lower end is also hinged to the adjusting arm 43 of the corresponding blade body 42 through a ball joint. Therefore, the upward movement of the piston rod 52 pushes each adjusting arm 43 through the connecting rod 53, thereby driving all blade bodies 42 to rotate synchronously and smoothly around their axis in a predetermined direction, such as counterclockwise, to increase the angle. During the entire adjustment process, especially when the blade body 42 rotates close to the preset limit position or is subjected to transient impact from the water flow, the moving column 57, which is rotatably connected to the adjusting arm 43, will slide relative to the corresponding fixed cylinder 56. At this time, the buffer device starts to work, and the damper 59 can effectively absorb and consume the impact kinetic energy transmitted from the adjusting arm 43, suppressing the vibration and instantaneous overshoot of the mechanism. At the same time, the return spring 58 sleeved outside the damper 59 undergoes elastic deformation and stores some energy. When the impact force decreases or the adjustment action stops, the return spring 58 releases the stored energy, pushes the moving column 57 and assists the adjusting arm 43 to return to a stable equilibrium position, ensuring the accuracy of blade positioning and the reliability of long-term operation of the mechanism. Conversely, when a clockwise rotation to reduce the blade angle is required, the hydraulic circuit supplies oil in the opposite direction, driving the piston rod 52 to move in the opposite direction. This, in turn, pulls the adjusting arm 43 via the connecting rod 53, causing the blade body 42 to rotate in the opposite direction. The buffer device also plays a role in buffering, absorbing vibration, and assisting in resetting during this process.

[0035] Among them: Cylinder 1 54 is the coarse adjustment chamber, which adopts a large-diameter piston and can quickly respond to the large angle adjustment (such as ±15°) of the blade body 42; Cylinder 2 55 is the fine adjustment chamber, which adopts a small-diameter piston and is superimposed on Cylinder 1 54. The flow rate is controlled by the throttle valve to achieve a fine adjustment of ±0.5°. At the very top of pump shaft 5, below coupling 11, is a four-channel high-pressure rotary distributor (not shown in the figure). The four-channel high-pressure rotary distributor can be an Rh400-25A-4ex, and includes: Static housing: fixed on bracket 12, and equipped with oil inlet 1, oil inlet 2, oil return port 1, and oil return port 2; Rotating spindle: Rotates coaxially with pump shaft 5, and has four longitudinal deep holes inside, which are respectively connected to oil cylinder 1 54 and oil cylinder 2 55. Oil inlet 1, oil inlet 2 and oil return port 1, oil return port 2 correspond to the four longitudinal deep holes and are connected to oil cylinder 1 54 and oil cylinder 2 55. Sealing pair: A combined slip ring seal is adopted, made of polytetrafluoroethylene (PTFE) and carbon fiber to withstand dynamic hydraulic pressure; Damper 59 uses silicone oil as the dielectric. The return spring 58 in this device uses the calculation formula for alloy springs: F=kx, where F is the external force on the spring, k is the spring constant, and x is the deformation of the spring. The elastic force of the alloy spring is then calculated so that it can be used in this device. The return spring 58 in this device can be made of 304 stainless steel wire.

[0036] The implementation principle of an adjustable blade vertical metal seawater circulating pump for nuclear power plants according to an embodiment of this application is as follows: After the adjustable-blade vertical metal seawater circulating pump for nuclear power plants is started, the motor 13 drives the pump shaft 5 and the mixed-flow impeller to rotate through the coupling 11. The water flows smoothly into the impeller chamber 2 through the suction horn 1, converting mechanical energy into the kinetic and pressure energy of the water. Subsequently, the high-speed water flows through the guide vane body 3 for rectification and conversion into pressure energy. Then, it passes through the flow channel formed by the connecting pipe 6, the protective sleeve pipe 7, and the outlet bend pipe 9 in sequence, achieving a gradual reduction in flow velocity and a smooth change in flow direction, and finally being discharged from the pump body. During this process, the pump shaft 5 is a water-lubricated shaft with an independent flushing system. Supported by bearing 8 and prevented from leaking by packing seal component 10, the core innovation of this pump lies in its pull-out core structure and hydraulic vane adjustment system: during maintenance, the rotor component can be pulled out as a whole, greatly simplifying the maintenance process. During operation, the piston rod 52 is driven to move linearly by the oil cylinder inside the pump shaft 5, and is converted into vane angle adjustment via connecting rod 53. At the same time, the damper 59 integrated in the hub 41 absorbs the impact and suppresses the vibration, ensuring smooth adjustment and accurate positioning, thereby achieving reliable, efficient and adaptive control of the pump unit performance.

[0037] The above are merely optional embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants, characterized in that: The system includes a connecting pipe (6) and a bracket (12). A pump shaft (5) is installed through the inside of the connecting pipe (6). A protective sleeve (7) is installed at the top of the connecting pipe (6). A water-lubricated bearing (8) is installed inside the protective sleeve (7). A water outlet bend (9) is installed at the top of the protective sleeve (7). A motor (13) is installed inside the bracket (12). The output shaft of the motor (13) is connected to the pump shaft (5) via a coupling (11). Packing material is installed between the water outlet bend (9) and the pump shaft (5). The sealing component (10) has a guide vane body (3) at the bottom of the connecting pipe (6), an impeller chamber (2) is provided inside the guide vane body (3), a suction horn (1) is provided at the bottom of the guide vane body (3), an impeller body (4) is provided inside the impeller chamber (2), the impeller body (4) is composed of a hub (41) and a blade body (42), the blade body (42) is evenly distributed on the outer surface of the hub (41) around the circumference, and the angle of the blade body (42) of the impeller body (4) is adjusted by hydraulic oil; The pump set adopts a core-removable structure, which allows the pump rotor component to be removed without removing the suction horn (1), connecting pipe (6) and outlet bend (9).

2. The adjustable-blade vertical metal seawater circulation pump for nuclear power plants according to claim 1, characterized in that: The output shaft of the motor (13) is rigidly connected to the pump shaft (5). The coupling (11) transmits the torque generated by the motor (13) from the output shaft of the motor (13) to the main shaft of the pump shaft (5) and transmits the thrust of the pump to the thrust bearing at the top of the motor (13).

3. A vertical metal seawater circulation pump with adjustable blades for nuclear power plants according to claim 1, characterized in that: The suction horn (1) is used to introduce water flow into the impeller body (4), and the suction horn (1) is horn-shaped.

4. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants according to claim 1, characterized in that: The guide vane body (3) is made of duplex stainless steel casting blades. The outer ring and inner ring are welded to the blades. The guide vane body (3) converts the medium velocity head at the blade outlet into pressure energy, collects the liquid flow and guides it through the connecting pipe (6) to the water outlet bend (9), and transports it to the water outlet pipe.

5. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants according to claim 1, characterized in that: The water outlet bend (9) is a guide component that changes the direction of water flow from vertical to horizontal, and its inner wall is smooth.

6. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants according to claim 1, characterized in that: A flow guide is provided at the outlet of the sheath tube (7), the flow guide has smooth flow lines, and multiple reinforcing ribs are welded between the sheath tube (7) and the flow guide.

7. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants according to claim 1, characterized in that: The water-lubricated bearing (8) is a guide bearing made of polymer material. The guide bearing allows the spindle to move axially within the guide bearing, and each bearing has an independent flushing water pipe.

8. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants according to claim 1, characterized in that: An adjusting arm (43) is provided on one side of the blade body (42), and the adjusting arm (43) is located inside the blade body (42). The pump shaft (5) is installed inside the hub (41). The pump shaft (5) is provided with a hydraulic cylinder (54) and a hydraulic cylinder (55) for adjusting hydraulic oil. A cylinder (51) is fixed on the outer surface of the pump shaft (5). A piston rod (52) is slidably installed inside the cylinder (51), and the piston rod (52) is slidably installed inside the cylinder (51). A connecting rod (53) is rotatably connected to the outer ring of the piston rod (52). The connecting rod (53) is rotatably connected to the adjusting arm (43). The piston rod (52) moves up and down to drive the connecting rod (53) to make the blade body (42) rotate clockwise or counterclockwise. A buffer device is provided on the inner wall of the hub (41).

9. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants according to claim 8, characterized in that: The buffer device includes a fixed cylinder (56) fixed inside the hub (41), and a movable column (57) rotatably connected inside the fixed cylinder (56) is rotatably provided on the outer surface of the adjusting arm (43). A damper (59) for absorbing and dissipating the impact energy of the blades by external forces is fixedly connected between the movable column (57) and the inner wall of the fixed cylinder (56). A return spring (58) is fixedly connected between the movable column (57) and the inner wall of the fixed cylinder (56). The return spring (58) is sleeved on the outer surface of the damper (59) to allow the movable column (57) to return to its initial position after being impacted.

10. A vertical metal seawater circulation pump with adjustable blades for use in nuclear power plants according to claim 1, characterized in that: The bracket (12) is a welded structure and is sprayed with anti-corrosion paint.

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