Anti-backflow monitoring device for liquid pipeline in nuclear power plant

Abstract

The utility model discloses a nuclear power station liquid pipeline inside anti -back flow monitoring devices, it includes shell, water stop, elastic member and micro -switch, shell is columnar structure, shell is used for installing in nuclear power station liquid pipeline inside top surface, and the upper end of water stop is located in the shell, and the upper end of water stop is connected through elastic member with the inner top surface of shell, and the lower end of water stop is located outside the shell, and the middle part of water stop is rotatably connected with the bottom wall of shell, and the part of water stop is located in the shell and is close to the bottom wall of shell is equipped with the waterproof film of isolation with the bottom wall of shell, micro -switch is installed in the inner top surface of shell, and the contact part of micro -switch is opposite and set up with the upper end of water stop. This nuclear power station liquid pipeline inside anti -back flow monitoring devices can real -time monitoring nuclear power station liquid pipeline inside fluid flow direction, can effectively avoid the influence that fluid back flow brings, and this nuclear power station liquid pipeline inside anti -back flow monitoring devices structure is relatively simple, and the manufacturing cost is lower, is favorable in nuclear power plant promotes application.

Description

Technical Field

[0001] This utility model relates to the field of nuclear power technology, and in particular to a backflow prevention monitoring device for liquid pipelines in nuclear power plants. Background Technology

[0002] Backflow, a typical abnormal flow pattern in nuclear power plant piping systems, can violate the unidirectional flow design principles of some systems and cause multiple risks: at the equipment level, backflow can cause pump impeller reversal, bearing overload and seal failure, while impacting valves and heat exchangers, causing structural damage and reduced heat transfer efficiency; at the system level, backflow may induce cross-contamination of primary / secondary loop radioactive fluids, cross-contamination of high / low radioactive systems, and interfere with instrument monitoring and core cooling functions. Under extreme conditions, it may even cause pipeline rupture due to water hammer effect or pressure boundary failure.

[0003] While current protective measures construct backflow prevention systems using manual or electromechanical barriers such as check valves and isolation valves, the sealing performance of valves is easily affected by dynamic pressure fluctuations and material deformation under high temperature and pressure, transient flow conditions, and complex thermal stress coupling, leading to instability of the locking threshold and the spread of radioactive or chemical contamination. Current pipeline liquid flow direction monitoring technologies fall into two categories: one involves placing pressure sensors inside the pipeline to detect sudden pressure drops caused by changes in flow direction; however, since pressure fluctuations can occur even when the fluid flow direction is normal, existing technologies carry a certain risk of misjudgment. The other category requires placing both flow direction sensors and flow velocity meters inside the pipeline; however, due to the radiation, high temperature and pressure, and even corrosive properties of some fluids in nuclear power plant pipeline systems, the internal chips and external structures of the sensors and flow velocity meters are easily damaged, leading to inaccurate functionality. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a backflow prevention monitoring device for liquid pipelines in nuclear power plants.

[0005] The technical solution adopted by this utility model to solve its technical problem is: to construct a backflow prevention monitoring device for liquid pipelines in nuclear power plants, including a shell, a water-blocking plate, an elastic element and a micro switch; The outer shell has a columnar structure and is used to be installed on the top surface of the liquid pipeline in the nuclear power plant. The upper end of the water-blocking plate is located inside the outer shell and is connected to the inner top surface of the outer shell through the elastic element. The lower end of the water-blocking plate is located outside the outer shell and the middle part of the water-blocking plate is rotatably connected to the bottom wall of the outer shell. The part of the water-blocking plate located inside the outer shell and close to the bottom wall of the outer shell is provided with an isolation waterproof membrane. The micro switch is installed on the inner top surface of the housing, and the contact portion of the micro switch is positioned opposite to the upper end of the water-blocking plate.

[0006] In some embodiments, the outer casing is cylindrical.

[0007] In some embodiments, the housing is a metal housing.

[0008] In some embodiments, the diameter of the outer casing is 3 cm.

[0009] In some embodiments, the portion of the water-blocking plate located outside the housing is rectangular in shape.

[0010] In some embodiments, the portion of the water-blocking plate located outside the outer casing has dimensions of 5cm in length, 4cm in width, and 0.5cm in thickness.

[0011] In some embodiments, the portion of the water-blocking plate located inside the housing is rectangular in shape.

[0012] In some embodiments, the middle part of the water-blocking plate is rotatably connected to the bottom wall of the outer casing via a pivot.

[0013] In some embodiments, the water-blocking plate is a metal water-blocking plate.

[0014] In some embodiments, the end of the housing is provided with a through hole for the control line of the micro switch to pass through, and a sealing ring is fitted around the outer periphery of the portion of the control line located in the through hole.

[0015] The present invention has the following advantages: the anti-backflow monitoring device for liquid pipelines in nuclear power plants can monitor the flow direction of fluids in liquid pipelines in real time, effectively avoiding the impact of fluid backflow. Moreover, the anti-backflow monitoring device for liquid pipelines in nuclear power plants has a relatively simple structure and low manufacturing cost, which is conducive to its widespread application in nuclear power plants. Compared with flow direction sensors and flow velocity meters, the anti-backflow monitoring device for liquid pipelines in nuclear power plants does not require periodic calibration or sensor replacement, significantly reducing the maintenance requirements throughout the entire life cycle and effectively improving convenience. Attached Figure Description

[0016] To more clearly illustrate the technical solution of this utility model, the present utility model will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show some embodiments of this utility model and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort. In the drawings: Figure 1 This is one of the structural application diagrams of the anti-backflow monitoring device in the liquid pipeline of the nuclear power plant in some embodiments of this utility model; Figure 2 This is the second schematic diagram of the structural application of the anti-backflow monitoring device in the liquid pipeline of the nuclear power plant in some embodiments of this utility model; Figure 3 This is the third schematic diagram of the structural application of the anti-backflow monitoring device in the liquid pipeline of the nuclear power plant in some embodiments of this utility model. Detailed Implementation

[0017] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or component referred to must have a specific orientation; therefore, they should not be construed as limitations on this utility model.

[0018] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. The terms "first," "second," "third," etc., are only for the convenience of describing this technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," "third," etc., may explicitly or implicitly include one or more of that feature. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0019] In the following description, specific details such as particular system structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will understand that the present invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0020] See Figure 1and Figure 2 This utility model discloses a backflow prevention monitoring device for liquid pipelines in nuclear power plants, including a shell 10, a water-blocking plate 20, an elastic element 30, and a micro switch 40.

[0021] The outer casing 10 has a columnar structure and is used to be installed on the inner top surface of the liquid pipeline 200 of the nuclear power plant. The upper end of the water-blocking plate 20 is located inside the outer casing 10, and the upper end of the water-blocking plate 20 is connected to the inner top surface of the outer casing 10 through the elastic member 30. The lower end of the water-blocking plate 20 is located outside the outer casing 10, and the middle part of the water-blocking plate 20 is rotatably connected to the bottom wall of the outer casing 10. The part of the water-blocking plate 20 located inside the outer casing 10 and close to the bottom wall of the outer casing 10 is provided with an isolation waterproof membrane 60.

[0022] The micro switch 40 is installed on the inner top surface of the housing 10, and the contact portion 41 of the micro switch 40 is disposed opposite to the upper end of the water-blocking plate 20.

[0023] This backflow prevention monitoring device for liquid pipelines in nuclear power plants can monitor the flow direction of fluids in the pipelines in real time, effectively avoiding the impact of backflow. Moreover, the device has a relatively simple structure and low manufacturing cost, which is conducive to its widespread application in nuclear power plants. Compared with flow direction sensors and flow velocity meters, this device does not require regular calibration or replacement of sensors, significantly reducing the maintenance requirements throughout its life cycle and effectively improving convenience.

[0024] See Figure 1 and Figure 2 In some embodiments, the outer casing 10 is cylindrical. The axis of the outer casing 10 is parallel to the axis of the nuclear power plant liquid pipeline 200. The outer casing 10 may be installed inside the nuclear power plant liquid pipeline 200 by laser welding. The cylindrical shape of the outer casing 10 avoids cavitation damage caused by local turbulence through its arc-shaped design.

[0025] In some embodiments, the housing 10 is a metal housing, preferably made of stainless steel, such as 316L stainless steel.

[0026] In some embodiments, the diameter of the outer casing 10 is 3 cm.

[0027] See Figure 1 and Figure 2 In some embodiments, the portion of the water-blocking plate 20 located outside the housing 10 is rectangular in shape.

[0028] In some embodiments, the portion of the water-blocking plate 20 located outside the housing 10 has dimensions of 5 cm in length, 4 cm in width, and 0.5 cm in thickness.

[0029] See Figure 1 and Figure 2 In some embodiments, the portion of the water-blocking plate 20 located inside the housing 10 is rectangular in shape, and may be a long rectangular structure.

[0030] See Figure 1 In some embodiments, the water-blocking plate 20 is normally inclined, and it may be oriented towards the countercurrent direction, such as... Figure 1 As shown, arrow A indicates the downstream direction, and arrow B indicates the upstream direction.

[0031] In some embodiments, the middle portion of the water-blocking plate 20 is rotatably connected to the bottom wall of the housing 10 via a pivot. The bottom wall of the housing 10 may be provided with a mounting base, and the middle portion of the water-blocking plate 20 is rotatably connected to the mounting base via a pivot. The mounting base may be provided with a movable groove, such as a rectangular movable groove, to allow the water-blocking plate 20 sufficient space to rotate. The waterproof membrane 60 can be used to isolate the movable groove, preventing external water from entering the housing 10. Of course, other rotating mounting methods can also be used for the water-blocking plate 20; no specific limitations are made here.

[0032] In some embodiments, the water-blocking plate 20 is a metal water-blocking plate. Preferably, the water-blocking plate 20 may be made of stainless steel, such as 316L stainless steel.

[0033] In some embodiments, the outer shell 10 and the water-blocking plate 20 may also be made of other radiation-resistant, high-temperature and high-pressure-resistant, and corrosion-resistant materials, which are not specifically limited here.

[0034] In some embodiments, the contact portion 41 of the micro switch 40 is disposed facing the end of the water-blocking plate 20. The specifications and model of the micro switch 40 can be selected according to actual needs, and are not specifically limited here.

[0035] In some embodiments, the end of the housing 10 is provided with a through hole for the control line of the micro switch 40 to pass through. A sealing ring is fitted around the outer periphery of the portion of the control line located within the through hole to improve sealing. Alternatively, the end of the housing 10 may be provided with a waterproof connector for connection. The control line can be connected to the control platform in the main control room.

[0036] In some embodiments, the elastic element 30 may be a helical column spring, which is in a compressed state under normal installation conditions.

[0037] In some embodiments, the backflow prevention monitoring device in the nuclear power plant liquid pipeline is welded to the upper side of the inner wall of the nuclear power plant liquid pipeline 200. The water-blocking plate 20 is used to receive the fluid. When the water-blocking plate 20 is only subjected to the elastic force of the elastic element 30, the lifting direction should be consistent with the direction of flow. When the normal flow direction of the fluid in the nuclear power plant liquid pipeline 200 is predetermined, if a flow occurs in the nuclear power plant liquid pipeline 200, the flow pushes the part of the water-blocking plate 20 located outside the outer casing 10 to retract towards the outer casing 10, while simultaneously causing the part of the water-blocking plate 20 located inside the outer casing 10 to move away from the contact portion 41 of the micro switch 40. When the normal flow direction of the fluid in the liquid pipeline 200 of the nuclear power plant is predetermined, if backflow occurs in the liquid pipeline 200 due to valve leakage, misoperation, or other reasons, the backflow will push the water-blocking plate 20 to move in a direction that overcomes the elastic force of the elastic element 30. When the backflow thrust exceeds the tension threshold of the elastic element 30, the part of the water-blocking plate 20 located inside the outer casing 20 will move closer to the contact part 41 of the micro switch 40 until the contact is pressed and the backflow signal is triggered. The tension threshold of the elastic element 30 can be determined by selecting appropriate material specifications according to actual needs, and is not specifically limited here.

[0038] The backflow prevention monitoring device inside the liquid pipeline of a nuclear power plant offers the following advantages: The device is small in size and its outer surface fits perfectly against the inner wall of the liquid pipeline 200. It can be directly fixed to the inner wall of the liquid pipeline 200 using underwater welding technology, eliminating the need for drilling holes in the liquid pipeline 200 or modifying its original structure. This avoids the installation complexity and project delays caused by traditional solutions that require emptying the pipeline, isolating the storage tank, or suspending system operation. This installation method can be implemented without interrupting system operation, effectively ensuring the economy and safety of continuous operation of nuclear power plant equipment, and is particularly suitable for nuclear energy systems where shutdown for maintenance is not feasible at any time.

[0039] The device's cross-sectional area is significantly smaller than the pipe diameter, generating only minimal resistance to forward-flowing water. The water-blocking plate 20 is rotatable, easily pushed and lifted by the water flow in the forward direction to ensure that the pipe flow rate is not significantly affected; in the reverse direction, it triggers a signal to avoid interference from abnormal flow patterns. This adaptive structure makes the device suitable for both unidirectional and bidirectional fluid pipelines, breaking through the limitation of traditional monitoring equipment's single adaptability to flow direction.

[0040] Backflow prevention monitoring devices in nuclear power plant liquid pipelines can serve as a redundant protection layer for check valves and isolation valves. They can monitor abnormal operating conditions caused by valve leakage or misoperation in real time, and work in conjunction with isolation valves to promptly cut off water flow, effectively preventing radioactive diffusion or thermal-hydraulic imbalance caused by cross-contamination between different systems. Compared to traditional monitoring solutions, this device significantly reduces production costs. Furthermore, it can be deployed on a large scale in various pipelines within nuclear power plants, forming a comprehensive backflow prevention protection network.

[0041] The backflow prevention monitoring device in the liquid pipelines of nuclear power plants adopts a mechanical monitoring mechanism, eliminating the need for periodic calibration or sensor replacement, significantly reducing the maintenance requirements throughout the entire life cycle. This technology transforms equipment modifications that traditionally required major overhauls into routine online implementations, effectively reducing project time and improving economic efficiency.

[0042] It should be noted that when the diameter of the pipeline in which the anti-backflow monitoring device is installed in the liquid pipeline of the nuclear power plant increases or decreases, the volume and placement of the anti-backflow monitoring device in the liquid pipeline of the nuclear power plant can be adjusted accordingly. When installed in a pipeline that transports fluids of different properties, the materials of the outer shell 10, water blocking plate 20, etc. of the anti-backflow monitoring device in the liquid pipeline of the nuclear power plant can be adjusted accordingly to ensure its resistance to radiation, high temperature and high pressure, and corrosion. The above two situations are still within the scope of protection of the technical solution.

[0043] like Figure 3 As shown, in some embodiments, the backflow prevention monitoring device in the nuclear power plant liquid pipeline is applied as follows: The backflow prevention monitoring device in the nuclear power plant liquid pipeline can be installed in the nuclear power plant liquid pipeline 200 that connects to the liquid storage pool 100, and the backflow prevention monitoring device in the nuclear power plant liquid pipeline is installed at one end of the nuclear power plant liquid pipeline 200 near the liquid storage pool 100, effectively avoiding the risk of false triggering of local disturbances in the pipeline area caused by routine operations such as filling and draining water and solid feeding.

[0044] The liquid pipeline 200 of the nuclear power plant is provided with a check valve 300, a first electric isolation valve 400 and a second electric isolation valve 500 in sequence from the side closer to the liquid storage pool 100 to the side farther away from the liquid storage pool 100. The second electric isolation valve 500 is set to be normally open and can be connected to the control platform in the main control room.

[0045] Specifically, when the fluid in the liquid pipeline 200 of the nuclear power plant triggers a backflow signal, the microswitch 40 can transmit the signal to the control platform in the main control room via the control line. After continuous triggering for N seconds, an alarm is generated in the control platform. After continuous triggering for M seconds, the second electric isolation valve 500 is interlocked to close, isolating the backflow pipeline and preventing the backflow range from expanding. When the backflow signal disappears on its own before the second electric isolation valve 500 is triggered, the second electric isolation valve 500 remains in its original open state. When the backflow is blocked by the interlocked second electric isolation valve 500, even if the backflow signal disappears, the second electric isolation valve 500 will not automatically return to the open state. It needs to be manually opened by the main control operator or on-site personnel to ensure that the consequences caused by the backflow do not continue to expand during the investigation of the backflow cause.

[0046] It is understood that the above embodiments only illustrate preferred embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present utility model patent. It should be noted that for those skilled in the art, the above technical features can be freely combined, and several modifications and improvements can be made without departing from the concept of the present utility model, all of which fall within the protection scope of the present utility model. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present utility model should fall within the coverage of the claims of the present utility model.

Claims

1. A backflow prevention monitoring device for liquid pipelines in a nuclear power plant, characterized in that, It includes a housing (10), a water-blocking plate (20), an elastic element (30), and a micro switch (40); The outer shell (10) has a columnar structure and is used to be installed on the top surface of the liquid pipeline in the nuclear power plant. The upper end of the water-blocking plate (20) is located inside the outer shell (10), and the upper end of the water-blocking plate (20) is connected to the inner top surface of the outer shell (10) through the elastic member (30). The lower end of the water-blocking plate (20) is located outside the outer shell (10), and the middle part of the water-blocking plate (20) is rotatably connected to the bottom wall of the outer shell (10). The part of the water-blocking plate (20) located inside the outer shell (10) and close to the bottom wall of the outer shell (10) is provided with an isolation waterproof membrane (60) with the bottom wall of the outer shell (10). The micro switch (40) is installed on the inner top surface of the housing (10), and the contact portion of the micro switch (40) is disposed opposite to the upper end of the water blocking plate (20).

2. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 1, characterized in that, The outer shell (10) is cylindrical.

3. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 2, characterized in that, The outer casing (10) is a metal casing.

4. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 3, characterized in that, The diameter of the outer shell (10) is 3 cm.

5. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 1, characterized in that, The water-blocking plate (20) located outside the outer shell (10) has a rectangular shape.

6. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 5, characterized in that, The dimensions of the water-blocking plate (20) located outside the outer shell (10) are 5cm in length, 4cm in width, and 0.5cm in thickness.

7. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 5, characterized in that, The portion of the water-blocking plate (20) located inside the outer shell (10) is rectangular in shape.

8. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 1, characterized in that, The middle part of the water-blocking plate (20) is rotatably connected to the bottom wall of the outer shell (10) via a rotating shaft.

9. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 1, characterized in that, The water-blocking plate (20) is a metal water-blocking plate.

10. The backflow prevention monitoring device for liquid pipelines in nuclear power plants according to claim 1, characterized in that, The end of the housing (10) is provided with a wire hole for the control line of the micro switch (40) to pass through, and a sealing ring is provided around the portion of the control line located in the wire hole.

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