Flow limiting device of nuclear power plant reactor coolant pump shaft seal flow isolation valve and isolation valve

Abstract

The utility model relates to a nuclear power plant reactor coolant pump shaft seal flow isolation valve flow limiting device and an isolation valve, the nuclear power plant reactor coolant pump shaft seal flow isolation valve flow limiting device comprises a rotating part, an end cover and a positioning part, and the rotating part is used for connecting a hand wheel; the rotating piece is provided with an avoiding hole and a limiting hole which are arranged at intervals, and the avoiding hole is used for allowing the valve rod to penetrate through. The limiting hole is formed around the avoiding hole and is arc-shaped; a connecting hole is formed in the end cover and used for being in threaded connection with the valve rod. The positioning piece is arranged between the rotating piece and the end cover and is provided with a through hole for the valve rod to penetrate through; the positioning piece is detachably connected with the end cover; the positioning piece is provided with a limiting piece which is movably arranged in the limiting hole in a penetrating mode. The device is simple in structure, convenient to operate and capable of achieving accuracy and rapidness of limiting opening adjustment of the isolation valve.

Description

Technical Field

[0001] This application relates to the field of nuclear power technology, and in particular to a flow limiting device and isolation valve for a reactor coolant pump shaft seal flow isolation valve in a nuclear power plant. Background Technology

[0002] During normal operation, one reactor coolant pump shaft seal water filter in a nuclear power plant is in operation while another is on standby. When the operating filter needs replacement due to high differential pressure, the standby filter must be activated. During the activation of the standby filter, even though it is already filled with water, the high pressure of the reactor coolant pump shaft seal water (approximately 170 bar) causes rapid fluctuations in the shaft seal water flow rate when the inlet isolation valve of the standby filter is opened, leading to a low shaft seal water flow alarm in the main control room. The same situation occurs during the filling and venting process after the standby filter replacement is completed. Frequent occurrences of this alarm interfere with the monitoring by the main control room operators and distract them.

[0003] This necessitates that the opening degree of the isolation valve at the inlet of the standby filter be as small as possible to avoid introducing fluctuations into the system. Therefore, it is necessary to design and develop an isolation valve flow-limiting device. Utility Model Content

[0004] This application provides a flow limiting device and an isolation valve for the shaft seal flow isolation valve of a reactor coolant pump in a nuclear power plant, so as to regulate the limiting opening degree of the isolation valve.

[0005] In a first aspect, this application provides a flow limiting device for a reactor coolant pump shaft seal flow isolation valve in a nuclear power plant, applied to an isolation valve, wherein the isolation valve includes a handwheel and a valve stem, the handwheel and the valve stem being threadedly connected; the flow limiting device for the reactor coolant pump shaft seal flow isolation valve in a nuclear power plant includes:

[0006] A rotating component is used to connect the handwheel; the rotating component is provided with clearance holes and limiting holes arranged at intervals, the clearance holes are used for the valve stem to pass through; the limiting holes are arranged around the clearance holes and are arc-shaped;

[0007] The end cap is provided with a connecting hole for threaded connection with the valve stem.

[0008] A positioning element is provided between the rotating element and the end cap, and has a through hole for the valve stem to pass through; the positioning element is detachably connected to the end cap; the positioning element is provided with a limiting element, which is movably inserted into the limiting hole.

[0009] Furthermore, the number of the limiting holes is multiple, and the multiple limiting holes are arranged at intervals and symmetrically;

[0010] The number of the limiting members is multiple, and each of the limiting members is movably inserted into one of the limiting holes.

[0011] Furthermore, it also includes a locking component, wherein the end cap is provided with a fixing hole and the positioning component is provided with an adjustment hole; the locking component is detachably inserted into the fixing hole and the adjustment hole.

[0012] Furthermore, the positioning element is also provided with a plurality of adjustment holes, which are symmetrically distributed around the through hole at intervals along the directional axis.

[0013] Furthermore, the number of adjustment holes ranges from 5 to 20.

[0014] Furthermore, the fixing hole is provided with an internal thread; the locking member includes an operating part and a locking part connected to the operating part, the locking part is provided with an external thread, the locking part is threadedly connected to the fixing hole, and the locking part passes through the adjusting hole; the operating part is located on the side of the end cover opposite to the positioning member;

[0015] Furthermore, the rotating member has at least one locking part on the side opposite to the positioning member, and the locking part is used to connect the handwheel.

[0016] Furthermore, the locking part includes two locking feet, which are spaced apart to form a locking groove for accommodating the spokes of the handwheel.

[0017] Furthermore, the end cap has a sleeve portion on the side facing the positioning member, the sleeve portion has the connecting hole, and the connecting hole has an internal thread; the sleeve portion passes through the through hole.

[0018] Secondly, this application provides an isolation valve, comprising:

[0019] Valve body;

[0020] A valve stem is movably inserted through the valve body;

[0021] A handwheel, which is rotatably mounted on the valve body and threadedly connected to the valve stem;

[0022] As described above, in the nuclear power plant reactor coolant pump shaft seal flow isolation valve flow limiting device, the rotating part of the nuclear power plant reactor coolant pump shaft seal flow isolation valve flow limiting device is connected to the handwheel; the valve stem passes through the clearance hole of the rotating part and the through hole of the positioning part, and is threadedly connected to the end cover.

[0023] The technical solution provided in this application has the following advantages compared with the prior art:

[0024] In the technical solution of this application, the flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump is applied to the isolation valve. A rotating component is connected to the handwheel of the isolation valve, and an end cap is threadedly connected to the valve stem of the isolation valve. A positioning component is connected to the end cap; rotation of the handwheel causes the rotating component to rotate relative to the positioning component. The cooperation between the limiting hole and the limiting component limits the rotation angle of the handwheel, thereby limiting the opening degree of the isolation valve and achieving the adjustment of the restricted opening degree of the isolation valve. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0028] Figure 1 A schematic diagram of a flow limiting device for a shaft seal flow isolation valve of a reactor coolant pump in a nuclear power plant, provided as an embodiment of this application;

[0029] Figure 2 for Figure 1 Another perspective illustration;

[0030] Figure 3 for Figure 1 A schematic diagram of its decomposed structure.

[0031] Explanation of reference numerals in the attached figures:

[0032] Rotating component 1, clearance hole 1a, limiting hole 1b, snap-fit ​​part 11, snap-fit ​​foot 111, snap-fit ​​groove 11a.

[0033] End cap 2, connecting hole 2a, fixing hole 2b, sleeve part 21,

[0034] Positioning component 3, through hole 3a, limiting component 31, adjusting hole 3b, assembly hole 3c.

[0035] Locking part 4, operating part 41, locking part 42. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0038] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0039] To address the technical problem that existing isolation valves are inconvenient to adjust when the opening degree needs to be limited, this application provides a flow limiting device for the shaft seal flow isolation valve of a nuclear power plant reactor coolant pump, which can adjust the limited opening degree of the isolation valve.

[0040] Firstly, Figures 1 to 3This application provides a flow limiting device for a nuclear power plant reactor coolant pump shaft seal flow isolation valve, applied to an isolation valve. The isolation valve includes a handwheel and a valve stem, which are threadedly connected. The flow limiting device includes a rotating component 1, an end cap 2, and a positioning component 3. The rotating component 1 is used to connect to the handwheel. The rotating component 1 has a clearance hole 1a and a limiting hole 1b spaced apart. The clearance hole 1a is used for the valve stem to pass through. The limiting hole 1b is arranged around the clearance hole 1a and is arc-shaped. The end cap 2 has a connecting hole 2a for threaded connection with the valve stem. The positioning component 3 is located between the rotating component 1 and the end cap 2 and has a through hole 3a for the valve stem to pass through. The positioning component 3 is detachably connected to the end cap 2. The positioning component 3 has a limiting component 31, which is movably inserted into the limiting hole 1b.

[0041] When the flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump is applied to the isolation valve, the rotating part 1 is connected to the handwheel of the isolation valve, and the end cover 2 is threadedly connected to the valve stem of the isolation valve. The positioning part 3 is connected to the end cover 2. The rotation of the handwheel causes the rotating part 1 to rotate relative to the positioning part 3. The cooperation between the limiting hole 1b and the limiting part 31 can limit the rotation angle of the handwheel, thereby limiting the opening degree of the isolation valve. This application has a simple structure, is easy to operate, and can achieve accurate and rapid adjustment of the isolation valve opening degree.

[0042] It should be noted that the valve body of the isolation valve is connected to the valve stem. When the handwheel is turned, it will cause the valve stem to translate, which in turn will cause the valve body to move. Adjusting the distance the valve body moves is the adjustment of the isolation valve's opening. In other words, the valve body opening can be adjusted by the angle of the handwheel rotation. During the translation of the valve stem, the end cover 2 and the positioning element 3 will also translate. The limiting element 31 has sufficient length to ensure that even if the positioning element 3 translates, the limiting element 31 will still pass through the limiting hole 1b, ensuring the limiting fit between the limiting hole 1b and the limiting element 31. The translation of the positioning element 3 is not a rotation, so it will not affect the relative rotation angle between the rotating element 1 and the positioning element 3, and therefore will not affect the valve body opening adjustment.

[0043] The central angle of the limiting hole 1b is less than 360°. In this embodiment, to achieve adjustment of the small opening of the isolation valve, the central angle of the limiting hole 1b is less than or equal to 180°. Thus, the maximum rotation angle of the handwheel is 180°.

[0044] like Figure 2 and Figure 3As shown, in this embodiment, the number of limiting holes 1b is multiple, and the multiple limiting holes 1b are arranged at intervals and symmetrically; the number of limiting members 31 is multiple, and each limiting member 31 is movably inserted into one of the limiting holes 1b. In this embodiment, the number of limiting holes is two, and the number of limiting members is also two. The limiting holes and limiting members are arranged in a one-to-one correspondence.

[0045] It is understandable that by setting multiple limiting holes 1b, and each limiting hole 1b having a limiting member 31 inserted therein, the limiting members 31 are symmetrically arranged on the side of the positioning member 3 facing the rotating member 1. When the limiting member 31 is resisted by the limiting hole 1b, multiple limiting members 31 receive resistance, so that the positioning member 3 is balanced by force, avoiding the positioning member 3 from deflection and shaking, and improving the stability and reliability of the rotating member 1 when rotating relative to the positioning member 3.

[0046] like Figures 1 to 3 As shown, in the technical solution of this embodiment, a locking member 4 is also included. The end cap 2 is provided with a fixing hole 2b, and the positioning member 3 is provided with an adjustment hole 3b. The locking member 4 is detachably inserted through the fixing hole 2b and the adjustment hole 3b.

[0047] It is understandable that locking and unlocking of positioning part 3 and end cover 2 can be achieved through locking part 4. When it is necessary to limit the rotation angle of rotating part 1, locking part 4 is locked to positioning part 3. In this way, when rotating part 1 is driven to rotate by handwheel, positioning part 3 will not rotate under the restriction of end cover 2. When it is not necessary to limit the rotation angle of rotating part 1, locking part 4 can be removed, so that locking part 4 and positioning part 3 are unlocked. At this time, positioning part 3 is a movable part. When rotating part 1 rotates, when limiting part 31 rotates to the limiting position of limiting hole 1b, the continuing rotation of rotating part 1 will drive positioning part 3 to rotate synchronously, and the rotation angle of rotating part 1 is not limited.

[0048] like Figure 3 As shown, in the technical solution of this embodiment, the positioning member 3 is further provided with a plurality of adjustment holes 3b, which are symmetrically spaced around the through hole 3a, that is, the plurality of adjustment holes 3b are spaced apart and evenly distributed along the direction surrounding the through hole 3a.

[0049] It is understandable that by setting multiple adjustment holes 3b, the rotation angle of the rotating component 1 can be further limited, that is, the valve body opening can be limited. In this embodiment, the minimum rotation angle of the rotating component 1 is the included angle between two adjacent adjustment holes 3b, and the maximum rotation angle is the angle value of the central angle of the limiting hole 1b.

[0050] The specific operation for limiting the minimum rotation angle is as follows: loosen the locking member 4, rotate the positioning member 3 so that the limiting member 31 moves to the limiting position of the limiting hole 1b, rotate the end cover 2 so that one fixing hole 2b of the end cover 2 corresponds to one adjusting hole 3b, determine the position of the end cover 2, and then rotate the positioning member 3 in the opposite direction so that the adjacent adjusting hole 3b corresponds to the fixing hole 2b. The locking member 4 passes through the adjusting hole 3b and the fixing hole 2b to lock the positioning member 3 and the end cover 2. At this time, the angle of the limiting member 31 offset from the limiting position corresponds to the angle between the two adjacent adjusting holes 3b (minimum rotation angle). In this way, the rotating member 1 can rotate at this minimum rotation angle, so as to achieve accurate control of the rotation angle of the rotating member 1.

[0051] It should be noted that by setting multiple adjustment holes 3b, the rotation angle of the rotating part 1 can be made to be two times, three times, etc., the minimum rotation angle.

[0052] In some embodiments, to facilitate understanding the positional relationship between the adjustment hole 3b and the fixing hole 2b, markings can be made on the outer periphery of the positioning member 3, with each marking corresponding to the center position of an adjustment hole 3b.

[0053] like Figure 3 As shown, in this embodiment, the number of adjusting holes 3b is 5-20. This allows for adjustment of more rotation angles of the rotating component, thereby enabling greater limitation of the opening degree.

[0054] like Figure 3 As shown, in this embodiment, the number of adjustment holes 3b is 16. In one embodiment, when the central angle of the limiting hole 1b is 180°, the rotation angle between the rotating part 1 and the handwheel can be limited to a minimum of 1 / 16 turn and a maximum of 1 / 2 turn.

[0055] like Figure 3 As shown, in this embodiment, the fixing hole 2b has an internal thread; the locking member 4 includes an operating part 41 and a locking part 42 connected to the operating part 41. The locking part 42 has an external thread and is threadedly connected to the fixing hole 2b. The locking part 42 passes through the adjusting hole 3b; the operating part 41 is located on the side of the end cover 2 away from the positioning member 3. This allows the locking member 4 to quickly limit the positioning member 3 and the end cover 2 and achieve quick disassembly, preventing the positioning member 3 from rotating. In one embodiment, to improve connection stability, the adjusting hole 3b may have an internal thread; in another embodiment, the hole wall of the adjusting hole 3b is designed to be smooth. The outer periphery of the locking part 42 abuts against the hole wall of the adjusting hole 3b.

[0056] In one embodiment, the outer wall of the operating part 41 is provided with knurling, which can improve the anti-slip effect and facilitate the disassembly and assembly of the locking part 4.

[0057] like Figures 1 to 3As shown, in this embodiment, the rotating member 1 has at least one locking part 11 on the side opposite to the positioning member 3, and the locking part 11 is used to connect the handwheel. It can be understood that the locking part 11 enables quick assembly of the rotating member 1 and the handwheel.

[0058] like Figure 3 As shown, in this embodiment, the locking part 11 includes two locking feet 111, which are spaced apart to form a locking groove 11a. The locking groove 11a is used to accommodate the spokes of the handwheel. The structure is simple and the installation is quick.

[0059] In this embodiment, there are multiple snap-fit ​​parts 11, and each snap-fit ​​part 11 is provided with a snap-fit ​​groove 11a, and each snap-fit ​​groove 11a is used to accommodate a spoke.

[0060] like Figure 3 As shown, in the technical solution of this embodiment, the end cap 2 is provided with a sleeve portion 21 on the side facing the positioning member 3, the sleeve portion 21 is provided with the connecting hole 2a, the connecting hole 2a is provided with internal thread; the sleeve portion 21 passes through the through hole 3a.

[0061] It is understandable that the threaded connection between the end cap 2 and the valve stem is achieved through the sleeve portion 21. The sleeve portion 21 has a certain length, which can improve the connection stability between the end cap 2 and the valve stem. The positioning member 3 is movably sleeved on the sleeve portion 21. Compared with the positioning member 3 being directly sleeved on the valve stem, this avoids the influence of the threads on the valve stem on the positioning member 3. In this embodiment, the sleeve extends into the clearance hole 1a, which can avoid the influence of the threads on the valve stem on the rotating member 1. At the same time, it can facilitate the quick coaxial assembly of the rotating member 1, the positioning member 3, and the end cap 2.

[0062] like Figure 3 As shown, in this embodiment, the positioning member 3 has an assembly hole 3c, and the limiting member 31 is detachably connected to the assembly hole 3c. In one embodiment, the limiting member 31 is threadedly connected to the assembly hole 3c. Limiting members 31 of different lengths can be replaced.

[0063] Secondly, this application provides an isolation valve, including a valve body, a valve stem, a handwheel, and the aforementioned flow limiting device for the shaft seal flow isolation valve of a nuclear power plant reactor coolant pump. The specific structure of this flow limiting device is as described in the above embodiments. Since this isolation valve adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here. The valve stem is movably inserted through the valve body; the handwheel is rotatably disposed on the valve body and threadedly connected to the valve stem; the rotating component 1 of the flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump is connected to the handwheel; the valve stem passes through the clearance hole 1a of the rotating component 1 and the through hole 3a of the positioning component 3, and is threadedly connected to the end cap 2.

[0064] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0065] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0066] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0067] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0068] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0069] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0070] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0071] The above description describes specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A flow limiting device for a shaft seal flow isolation valve of a reactor coolant pump in a nuclear power plant, applied to an isolation valve, the isolation valve comprising a handwheel and a valve stem, the handwheel and valve stem being threadedly connected; characterized in that, The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump includes: A rotating component (1) is used to connect the handwheel; the rotating component (1) is provided with a clearance hole (1a) and a limiting hole (1b) arranged at intervals, the clearance hole (1a) is used for the valve stem to pass through; the limiting hole (1b) is arranged around the clearance hole (1a) and is arc-shaped; The end cap (2) is provided with a connecting hole (2a), which is used for threaded connection with the valve stem; A positioning element (3) is provided between the rotating element (1) and the end cap (2), and has a through hole (3a) through which the valve stem passes; the positioning element (3) is detachably connected to the end cap (2); the positioning element (3) is provided with a limiting element (31), which is movably inserted into the limiting hole (1b).

2. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 1, characterized in that, The number of the limiting holes (1b) is multiple, and the multiple limiting holes (1b) are arranged at intervals and symmetrically; The number of the limiting members (31) is multiple, and each of the limiting members (31) is movably inserted into one of the limiting holes (1b).

3. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 1, characterized in that, It also includes a locking member (4), the end cap (2) is provided with a fixing hole (2b), and the positioning member (3) is provided with an adjustment hole (3b); the locking member (4) is detachably inserted into the fixing hole (2b) and the adjustment hole (3b).

4. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 3, characterized in that, The positioning element (3) is also provided with a plurality of adjustment holes (3b), which are symmetrically distributed around the through hole (3a).

5. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 4, characterized in that, The number of the adjustment holes (3b) ranges from 5 to 20.

6. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 4, characterized in that, The fixing hole (2b) is provided with an internal thread; the locking member (4) includes an operating part (41) and a locking part (42) connected to the operating part (41). The locking part (42) is provided with an external thread. The locking part (42) is threadedly connected to the fixing hole (2b). The locking part (42) passes through the adjusting hole (3b). The operating part (41) is located on the side of the end cover (2) away from the positioning member (3).

7. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 1, characterized in that, The rotating member (1) has at least one snap-fit ​​part (11) on the side opposite to the positioning member (3), and the snap-fit ​​part (11) is used to connect the handwheel.

8. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 7, characterized in that, The latching part (11) includes two latching feet (111), which are spaced apart to form a latching groove (11a) for accommodating the spokes of the handwheel.

9. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump according to claim 1, characterized in that, The end cap (2) has a sleeve portion (21) on the side facing the positioning member (3), the sleeve portion (21) has the connecting hole (2a), the connecting hole (2a) has an internal thread; the sleeve portion (21) passes through the through hole (3a).

10. An isolation valve, characterized in that, include: Valve body; A valve stem is movably inserted through the valve body; A handwheel is rotatably mounted on the valve body and threadedly connected to the valve stem. The flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump as described in any one of claims 1 to 9, wherein the rotating part (1) of the flow limiting device for the shaft seal flow isolation valve of the nuclear power plant reactor coolant pump is connected to the handwheel; the valve stem passes through the clearance hole (1a) of the rotating part (1) and the through hole (3a) of the positioning part (3), and is threadedly connected to the end cover (2).

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