Fastener anti-loosening system and method for comprehensive flow-induced vibration test of reactor internals

Abstract

The invention provides a fastener anti-loosing system and method for a reactor internal comprehensive flow-induced vibration test, the system comprises a stud, an anti-loosing cup and a locking nut, the stud comprises a screw head and a threaded column, one end of the screw head deviating from the threaded column is connected with a first plate body, the threaded column is arranged in a matching hole of a second plate body in a penetrating manner, and the locking cup is connected with the locking nut. A placing groove communicated with the matching hole is formed in the second plate body above the matching hole, and the circumferential size of the placing groove is larger than that of the matching hole; the anti-loosening cup sleeves the outer side of the threaded column and is arranged in the placing groove; the locking nut is arranged on the outer side of the threaded column in a sleeving mode and is in threaded fit with the threaded column, and the locking nut is located in the anti-loosening cup; the locking nut or the second plate body is provided with at least two clamping grooves in the top of the containing groove, and the top of the anti-loosening cup is pressed to the clamping grooves so as to be fixedly connected with the locking nut or the second plate body. According to the anti-loosening system, underwater welding can be avoided, and the underwater installation convenience is improved on the premise that the anti-loosening effect is considered.

Description

Technical Field

[0001] The present invention relates to the technical field of fastener anti-loosening, and particularly relates to a fastener anti-loosening system and method for comprehensive flow-induced vibration tests of in-core components. Background Art

[0002] There are a large number of fasteners in the structure of reactor in-core components. At present, the anti-loosening structures of fasteners all need to achieve limit through welding with the installation surface. However, welding has a large heat input, which causes deformation in the relevant area. Before welding, visual inspection and penetrant inspection need to be carried out on the surface to be welded. After welding, visual inspection and penetrant inspection need to be carried out on the weld surface, resulting in a large amount of work.

[0003] At the same time, in some areas or positions, due to the size limitation of the anti-loosening structure, the welds are in the form of spot welding, and there is a situation where penetrant inspection cannot be carried out, which cannot guarantee the weld quality.

[0004] The prototype reactor needs to carry out comprehensive flow-induced vibration tests of in-core components to verify the structural design of in-core components. During the comprehensive flow-induced vibration tests of in-core components, a large number of sensors need to be installed, and a large number of fasteners also need to be installed to fix relevant test accessories. If the traditional anti-loosening structure is used, a large amount of welding is required, which causes more deformation on the surface of in-core components, and the operating space in some areas is limited, and the weld quality cannot be guaranteed.

[0005] At the same time, there is a situation where fasteners fall off during the operation of in-core components. Due to the neutron activation effect of materials and the deposition of fission products on the surface during the operation of in-core components, there is radioactivity, and maintenance needs to be carried out underwater. The traditional anti-loosening structure is welded, so there is a problem of difficult underwater maintenance.

[0006] Based on this, the inventors of the present application propose a fastener anti-loosening system and method for comprehensive flow-induced vibration tests of in-core components in order to solve one or more of the above technical problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defect of poor fastening quality of fasteners in the prior art, and provide a fastener anti-loosening system and method for comprehensive flow-induced vibration tests of in-core components.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] The present invention provides a fastener anti-loosening system for comprehensive flow-induced vibration tests of in-core components, including:

[0010] The stud comprises a screw head and a threaded column, wherein the end of the screw head facing away from the threaded column is connected to the first plate body, the threaded column is passed through the matching hole of the second plate body, and the second plate body is provided with a placement groove communicating with the matching hole above the matching hole, and the circumferential dimension of the placement groove is larger than the matching hole;

[0011] An anti-loosening cup, sleeved on the outer side of the threaded column and placed in the placement groove;

[0012] A locking nut is sleeved on the outside of the threaded column and matched with the thread of the threaded column, and the locking nut is located in the anti-loosening cup; wherein,

[0013] The locking nut or the second plate is provided with at least two clamping grooves at the top of the placement groove, and the top of the anti-loosening cup is fixedly connected with the locking nut or the second plate by being pressed to the clamping grooves.

[0014] According to one embodiment of the present invention, at least two positioning keys are provided on the periphery of the anti-loosening cup;

[0015] The second plate body is provided with at least two positioning grooves along the circumference of the placement groove, and the positioning key is axially penetrated in the positioning groove along the matching hole.

[0016] According to one embodiment of the present invention, at least two snap-in grooves are provided on the top of the locking nut along its circumference, and the top portion of the anti-loosening cup is pressed inwardly into the snap-in groove to be fixedly connected with the locking nut.

[0017] According to an embodiment of the present invention, a screw hole that matches with the threaded column thread is opened in the middle of the locking nut, and a cross groove is arranged on the top of the locking nut to match with an external locking tool.

[0018] According to an embodiment of the present invention, a positioning hole is provided at the bottom of the anti-loosening cup, and a positioning protrusion is provided at the bottom of the locking nut to be clamped in the positioning hole;

[0019] The second plate body is provided with at least two clamping grooves in the circumferential direction of the top of the placement groove, and the top portion of the anti-loosening cup is pressed outwardly into the clamping groove to be fixedly connected with the second plate body.

[0020] According to one embodiment of the present invention, the cross-sectional shape of the positioning hole is a polygon;

[0021] The cross-sectional shape of the positioning protrusion is consistent with the cross-sectional shape of the positioning hole.

[0022] According to an embodiment of the present invention, a stress release groove is provided in an angle region between adjacent sides of the positioning hole, and the stress release groove is communicated with the inner side of the positioning hole.

[0023] According to an embodiment of the present invention, at least two of the clamping grooves are evenly distributed circumferentially around the top of the locking nut or circumferentially around the top of the second plate body in the placement groove.

[0024] According to an embodiment of the present invention, the axial cross-section of the clamping groove along the locking nut or the mating hole is conical.

[0025] The present invention also provides a method for preventing loosening of fasteners for the comprehensive flow-induced vibration test of in-core components, which is implemented by using the fastener anti-loosening system for the comprehensive flow-induced vibration test of in-core components as described above. The anti-loosening method includes:

[0026] Put an anti-loosening cup outside the stud and then screw the locking nut to the stud head according to the target torque;

[0027] Press the top surface of the anti-loosening cup into the clamping groove provided on the locking nut or the second plate body to prevent loosening of the fastener.

[0028] The positive and progressive effects of the present invention are as follows:

[0029] For the fastener anti-loosening system for the comprehensive flow-induced vibration test of in-core components of the present invention, an anti-loosening cup is arranged on the top of the stud to limit the locking nut. Therefore, there is no need to weld the locking nut and the stud, avoiding the problem of radioactive aerosol caused by underwater welding. Furthermore, it meets the underwater installation requirements, and can be remotely carried out underwater by using tools, with convenient installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above-mentioned and other features, properties and advantages of the present invention will become more obvious through the following description in conjunction with the drawings and embodiments, where:

[0031] Figure 1 is a sectional view from an angle of an embodiment of the fastener anti-loosening system for the comprehensive flow-induced vibration test of in-core components of the present invention;

[0032] Figure 2 is Figure 1 an exploded view of the stud, anti-loosening ring and locking nut in

[0033] Figure 3 is Figure 1 a top view of

[0034] Figure 4 is an exploded view of the stud, anti-loosening ring and locking nut of another embodiment of the fastener anti-loosening system for the comprehensive flow-induced vibration test of in-core components of the present invention;

[0035] Figure 5 is an exploded view of the stud, anti-loosening ring and locking nut of yet another embodiment of the fastener anti-loosening system for the comprehensive flow-induced vibration test of in-core components of the present invention;

[0036] Figure 6 for Figure 5 Exploded view of the center stud, anti-loosening ring and locking nut from another perspective.

[0037] 1. Stud; 11. Screw head; 12. Threaded column;

[0038] 2. The first plate;

[0039] 3. Second plate; 31. Matching hole; 32. Placement groove; 33. Positioning groove;

[0040] 4. Anti-loosening cup; 41. Positioning key; 42. Positioning hole; 421. Stress relief groove;

[0041] 5. Locking nut; 51. Snap-fit groove; 52. Cross groove; 53. Positioning protrusion. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0044] Please refer to Figures 1 to 6 The present invention proposes a fastener anti-loosening system for comprehensive flow-induced vibration test of in-core components, including a stud 1, an anti-loosening cup 4 and a locking nut 5. The stud 1 includes a screw head 11 and a threaded column 12. The end of the screw head 11 facing away from the threaded column 12 is connected to the first plate body 2. The threaded column 12 is penetrated into the matching hole 31 of the second plate body 3. The second plate body 3 is provided with a placement groove 32 connected to the matching hole 31 above the matching hole 31, and the circumferential size of the placement groove 32 is larger than the matching hole 31.

[0045] The anti-loosening cup 4 is sleeved outside the threaded stud 12 and placed in the placement groove 32; the locking nut 5 is sleeved outside the threaded stud 12 and is in threaded cooperation with the threaded stud 12, and the locking nut 5 is located inside the anti-loosening cup 4. Among them, at least two clamping grooves 51 are provided at the top of the locking nut 5 or the second plate body 3 in the placement groove 32, and the top of the anti-loosening cup 4 is pressed into the clamping groove 51 to be fixedly connected with the locking nut 5 or the second plate body 3.

[0046] After the traditional stud 1 connects the first plate body 2 and the second plate body 3, the locking nut 5 is used for locking, and then the stud 1 and the locking nut 5 are further welded. On the one hand, limited by the dimensional space between the locking nut 5 and the stud 1, the welding method between the stud 1 and the locking nut 5 is spot welding, and there are problems with poor weld quality in spot welding. Therefore, the locking nut 5 is prone to detachment from the stud 1 under the impact of the coolant in the flow-induced vibration test; on the other hand, when the in-core components are operating, the stud 1 is underwater. Once maintenance is required, there are problems of difficult underwater welding and thus difficult maintenance.

[0047] Based on this, the present invention sleeved the anti-loosening cup 4 outside the stud 1, and then the locking nut 5 presses the anti-loosening cup 4 into the placement groove 32. At the same time, a partial area at the top of the anti-loosening cup 4 is pressed into the clamping groove 51 provided on the second plate body 3 or the locking nut 5. Thus, the connection stability between the locking nut 5 and the stud 1 can be improved by using the anti-loosening cup 4.

[0048] The setting method of the stud 1, the locking nut 5 and the anti-loosening cup 4 of the present invention can be used in the flow-induced vibration test of in-core components. In the flow-induced vibration test, it is required that the fasteners cannot fall off, and the structure of the in-core components should not be damaged as much as possible during the test. Instead of using welding to prevent loosening of the locking nut 5 and the stud 1, the present application uses the anti-loosening cup 4 to prevent the locking nut 5 from rotating. Thus, it has the advantages of convenient installation and good anti-loosening effect, and meets the connection strength requirements between the stud 1 and the locking nut 5 in the flow-induced vibration test.

[0049] Moreover, the present invention is also convenient for maintenance after the test. The staff can use a long-handled tool to disassemble and assemble the locking nut 5 and the anti-loosening cup 4, and the disassembly and assembly process is very convenient.

[0050] It can be seen that the middle part of the anti-loosening cup 4 has a cavity, and there is an avoidance hole in the middle of the cavity for avoiding the stud 1. Thus, the anti-loosening cup 4 can be sleeved outside the stud 1, and the size of the locking nut 5 corresponds to the cavity. Thus, the locking nut 5 can be sleeved outside the stud 1 and located inside the cavity.

[0051] By setting the anti-loosening cup 4, the anti-loosening cup 4 cooperates with the second plate body 3 and the locking nut 5 respectively, which is convenient for installation, and there is no need to weld the locking nut 5 and the stud 1. Furthermore, the problem of radioactive aerosol caused by underwater welding can be avoided, and rapid underwater installation can be achieved, and the anti-loosening requirements are met.

[0052] It should be noted that the stud 1 of the present invention is a threaded connector including a screw head 11 and a threaded column 12. Similar structures such as screws also fall within the scope of implementation of the present invention and are also protected by the present invention, and are not listed here.

[0053] Please refer to Figures 1 to 3 At least two positioning keys 41 are provided on the circumferential side of the anti-loosening cup 4; at least two positioning grooves 33 are opened circumferentially along the placement groove 32 of the second plate body 3, and the positioning key 41 is axially penetrated in the positioning groove 33 along the matching hole 31.

[0054] That is, the shape of the placement groove 32 is adapted to the shape of the anti-loosening cup 4. The circle is taken as an example here for explanation. The placement groove 32 is coaxially arranged with the matching block. The positioning key 41 arranged on the anti-loosening cup 4 is used to cooperate with the positioning groove 33 arranged on the placement groove 32. On the one hand, it is used to guide the installation of the anti-loosening cup 4, and on the other hand, it can play a role of stopping rotation.

[0055] For example, when the locking nut 5 and the stud 1 become loose and tend to rotate, the rotational force will be transmitted to the anti-loosening cup 4, and the positioning key 41 of the anti-loosening cup 4 is restricted by the positioning groove 33 to form a rotation stop, thereby the anti-loosening cup 4 stops the locking nut 5 from rotating.

[0056] Please refer to Figure 2 and Figure 4 The number of the positioning keys 41 can be two or three, or more, which is not limited here.

[0057] Furthermore, at least two clamping grooves 51 are provided at the top of the locking nut 5 along its circumference, and the top portion of the anti-loosening cup 4 is pressed inwardly into the clamping groove 51 to be fixedly connected with the locking nut 5 .

[0058] The number of the clamping grooves 51 can be two, three or more, which is not limited here. At least two clamping grooves 51 are evenly distributed around the top circumference of the locking nut 5, so that the force between the anti-loosening cup 4 and the locking nut 5 after being pressed together is more uniform, which is conducive to stopping rotation.

[0059] Optionally, the engaging groove 51 has a conical cross-sectional shape along the axial direction of the locking nut 5 , thereby improving the connection stability between the anti-loosening cup 4 and the locking nut 5 after being pressed together.

[0060] That is, the depth of the conical snap-fit groove 51 is deeper, so after the anti-loosening cup 4 and the locking nut 5 are pressed together, the contact area between the anti-loosening cup 4 and the locking nut 5 in the snap-fit groove 51 is larger, and the connection between the anti-loosening cup 4 and the locking nut 5 is tighter.

[0061] Optionally, a crimping pliers can be used to press the top part structure of the anti-loosening cup 4 into the clamping groove 51, thereby realizing the mechanical locking of the anti-loosening cup 4 and the second plate body 3. Alternatively, a hydraulic press head or a pneumatic press head can be used instead, which is not limited herein.

[0062] In one embodiment, a threaded hole that is threadedly engaged with the threaded post 12 is formed in the middle of the lock nut 5, and a cross groove 52 is provided at the top of the lock nut 5 to cooperate with an external locking tool.

[0063] To improve the underwater installation and maintenance efficiency, a cross groove 52 is provided at the top of the lock nut 5, so that the staff can use a long-handled locking tool to install the lock nut 5 and the anti-loosening cup 4 underwater.

[0064] Thus, the lock nut 5 and the anti-loosening cup 4 can be used for the maintenance of the in-core components after the fuel assembly operates, without welding, and can be remotely maintained underwater, and the requirements for installation tools are also very low.

[0065] Please refer to Figure 5 and Figure 6 , a positioning hole 42 is formed at the bottom of the anti-loosening cup 4, and a positioning protrusion 53 that is clamped in the positioning hole 42 is provided at the bottom of the lock nut 5; at least two clamping grooves 51 are circumferentially formed at the top of the placing groove 32 of the second plate body 3, and the top part of the anti-loosening cup 4 is pressed outward into the clamping groove 51 to be fixedly connected to the second plate body 3.

[0066] That is to say, after the lock nut 5 is engaged with the stud 1, the bottom is restricted by the positioning hole 42 and can play an anti-loosening effect.

[0067] For example, when the lock nut 5 rotates relative to the stud 1, the rotational force of the lock nut 5 is transmitted to the anti-loosening cup 4 by the positioning protrusion 53, and then a part of the anti-loosening cup 4 is pressed into the clamping groove 51 of the second plate body 3. Thus, restricted by the second plate body 3, the anti-loosening cup 4 can restrict the rotation of the lock nut 5, and further realize the anti-rotation function, so as to ultimately improve the connection stability between the lock nut 5 and the stud 1.

[0068] That is to say, in this embodiment, the anti-loosening cup 4 is pressed outward into the clamping groove 51, and the clamping groove 51 is arranged on the second plate body 3.

[0069] Optionally, the cross-sectional shape of the positioning hole 42 is a polygon, such as a triangle, a quadrilateral, a pentagon, etc., which is not limited herein. Correspondingly, the shape of the positioning protrusion 53 is also a triangle, a quadrilateral, and a pentagon.

[0070] Thus, under the cooperation of the positioning protrusion 53 and the positioning hole 42, the anti-loosening cup 4 can prevent the lock nut 5 from loosening.

[0071] Further, a stress relief groove 421 is provided in the angular region of the adjacent sides of the positioning hole 42, and the stress relief groove 421 communicates with the inner side of the positioning hole 42.

[0072] To prevent stress concentration from occurring at the angle of the adjacent sides of the positioning hole 42 under the rotational load of the positioning protrusion 53, a stress relief groove 421 is opened in this region, thereby releasing the concentrated load at the position of the adjacent side angle.

[0073] In summary, in the present invention, a lock nut cup 4 is provided outside the stud 1. The lock nut cup 4, the lock nut 5 and the stud 1 are not welded together, thus avoiding the problem of radioactive aerosol caused by underwater welding. Moreover, the installation method of the lock nut cup 4 and the lock nut 5 is simple and has low requirements for the installation and the installation environment, thus meeting the maintenance requirements after the in-core components operate and the usage requirements of the in-core components comprehensive fluid-induced vibration test.

[0074] The present invention also proposes a method for preventing loosening of fasteners for the in-core components comprehensive fluid-induced vibration test, which is realized by using the above-mentioned fastener anti-loosening system for the in-core components comprehensive fluid-induced vibration test. The anti-loosening method includes:

[0075] Put a lock nut cup outside the stud and then screw the lock nut to the stud head according to the target torque;

[0076] Press the top surface of the lock nut cup into the clamping groove provided on the lock nut or the second plate body to prevent loosening of the fastener.

[0077] For the cooperation between the lock nut and the stud, the traditional method is welding for anti-loosening. However, if the lock nut becomes loose during maintenance, since the stud is underwater, underwater welding is likely to generate radioactive aerosol, and thus the welding quality cannot be guaranteed, presenting the defect of difficult maintenance.

[0078] In the present invention, through the lock nut cup and by borrowing the second plate body, the rotational force of the lock nut can be transmitted to the lock nut cup and finally to the second plate body. The lock nut cup and the second plate body are used to prevent loosening of the lock nut. In this way, the anti-loosening effect can be achieved without welding, and the installation process is very convenient, meeting the requirements for the quick installation and maintenance of the lock nut.

[0079] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "coupling", "fixation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral body; it can also be a mechanical connection. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0080] This application uses specific terms to describe the embodiments of this application. For example, "an embodiment", "one embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0081] Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A fastening anti-loosening system for the comprehensive flow-induced vibration test of in-core components, characterized in that include: The stud comprises a screw head and a threaded column, wherein the end of the screw head facing away from the threaded column is connected to the first plate body, the threaded column is passed through the matching hole of the second plate body, and the second plate body is provided with a placement groove communicating with the matching hole above the matching hole, and the circumferential dimension of the placement groove is larger than the matching hole; An anti-loosening cup, sleeved on the outer side of the threaded column and placed in the placement groove; A locking nut is sleeved on the outside of the threaded column and matched with the thread of the threaded column, and the locking nut is located in the anti-loosening cup; wherein, The locking nut or the second plate is provided with at least two clamping grooves at the top of the placement groove, and the top of the anti-loosening cup is fixedly connected with the locking nut or the second plate by being pressed to the clamping grooves.

2. The anti-loosening system for fasteners in the comprehensive flow-induced vibration test of in-core components according to claim 1, wherein At least two positioning keys are provided on the periphery of the anti-loosening cup; The second plate body is provided with at least two positioning grooves along the circumference of the placement groove, and the positioning key is axially penetrated in the positioning groove along the matching hole.

3. The anti-loosening system for fasteners in the comprehensive flow-induced vibration test of in-core components according to claim 2, characterized in that, The top of the locking nut is provided with at least two snap-fit grooves along its circumference, and the top portion of the anti-loosening cup is pressed inwardly into the snap-fit groove to be fixedly connected with the locking nut.

4. The anti-loosening system for fasteners in the comprehensive flow-induced vibration test of in-core components according to claim 1, wherein A screw hole that matches with the threaded column thread is provided in the middle of the locking nut, and a cross groove is provided on the top of the locking nut to match with an external locking tool.

5. The anti-loosening system for fasteners in the comprehensive flow-induced vibration test of in-core components according to claim 1, characterized in that, A positioning hole is provided at the bottom of the anti-loosening cup, and a positioning protrusion is provided at the bottom of the locking nut to be clamped in the positioning hole; The second plate body is provided with at least two clamping grooves in the circumferential direction of the top of the placement groove, and the top portion of the anti-loosening cup is pressed outwardly into the clamping groove to be fixedly connected with the second plate body.

6. The anti-loosening system for fasteners in the comprehensive flow-induced vibration test of in-core components according to claim 5, characterized in that, The cross-sectional shape of the positioning hole is a polygon; The cross-sectional shape of the positioning protrusion is consistent with the cross-sectional shape of the positioning hole.

7. The anti-loosening system for fasteners in the comprehensive fluid-induced vibration test of in-core components according to claim 5, characterized in that, A stress release groove is provided in an angle region between adjacent sides of the positioning hole, and the stress release groove is communicated with the inner side of the positioning hole.

8. The anti-loosening system for fasteners in the comprehensive fluid-induced vibration test of in-core components according to claim 1, wherein, At least two of the clamping grooves are evenly distributed around the circumference of the top of the locking nut or the second plate is evenly distributed around the circumference of the top of the placement groove.

9. The anti-loosening system for fasteners in the comprehensive fluid-induced vibration test of in-core components according to claim 1, characterized in that, The engaging groove is tapered along the axial cross section of the locking nut or the matching hole.

10. A method for preventing loosening of fasteners for comprehensive in-core component flow-induced vibration tests, characterized in that, The method is implemented by using the fastener anti-loosening system for the comprehensive flow-induced vibration test of the in-core components according to any one of claims 1 to 9, wherein the anti-loosening method comprises: A locking cup is sleeved on the outside of the stud and then the locking nut is screwed to the screw head according to the target torque; The top surface of the anti-loosening cup is pressed into the clamping groove provided on the locking nut or the second plate body to prevent the fastener from loosening.

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