A bending moment test detection device

Abstract

The application is suitable for the technical field of valve detection and production, and provides a bending moment test detection device, which comprises two bases, two vertical supports fixed on the two bases, an assembling frame arranged on one side of the two bases, a horizontal extension part extending to the vertical support direction on the top of the assembling frame, a limiting mechanism arranged on the two vertical supports and used for fixing the pipe and the valve from both ends, a bracket arranged on the top of the vertical support and used for supporting the pipe, and an adjustable counterweight mechanism arranged on the assembling frame and used for applying adaptive bending moment load to the pipe. The device can complete the bending moment test parallel to the valve rod axis and the bending moment test perpendicular to the valve rod axis.

Description

Technical Field

[0001] This invention belongs to the field of valve testing technology, and in particular relates to a bending moment test device. Background Technology

[0002] In fluid transportation fields such as water supply systems, large-diameter valves are key control components. Their structural strength and sealing performance under complex working conditions directly determine the operational stability of the entire pipeline system. After production, large-diameter valves need to undergo bending moment type tests to verify their resistance to deformation and leakage prevention when subjected to external bending loads (such as foundation settlement, geological deformation, external extrusion, etc.).

[0003] For example, Chinese Utility Model Patent Publication No. CN216410557U discloses a valve test bench with bending moment detection function, including a base frame and a fixed platform vertically fixed on the base frame. Two movable frames are slidably connected to the fixed platform, and two clamping cylinders are slidably connected between the two movable frames. A bending moment pressure head is fixedly connected to the output end of the clamping cylinders. The fixed platform is respectively equipped with a first drive assembly and a second drive assembly to drive the two movable frames and the two clamping cylinders to move in opposite directions or away from each other. The first drive assembly and the second drive assembly are of the same specifications. A conformal fitting part is provided on the movable frame, and a workpiece clamping mouth is formed between the bending moment pressure head and the conformal fitting part. This patent can perform bending moment testing on valves of various sizes. However, the bending moment test of this patent violates the bending moment test method. According to Appendix C of GB / T 37827-2019 "Welded Ball Valves for Urban Heating" bending moment test method, the test force is applied to the pipes at both ends of the valve, not to the valve itself. Therefore, the data measured by this patent is inaccurate. A complete bending moment test includes tests parallel to the valve stem axis (primarily assessing axial load and stability) and tests perpendicular to the valve stem axis (primarily assessing bending resistance and sealing performance). The test parallel to the valve stem axis primarily simulates the axial forces that the valve stem may experience and assesses their impact on the bearings. When the valve stem is subjected to thrust or tension along its axis, it may cause additional load on the bearings, slight axial displacement of the valve stem, and even affect sealing performance. This test verifies the stability of the valve stem and bearing system under axial forces, ensuring that the valve will not jam or experience abnormal wear under pressure. The test perpendicular to the valve stem axis is the focus of the bending moment test. This test simulates the valve stem's ability to resist bending moments. When a medium (such as water) flows through the valve, especially causing uneven impact on the butterfly plate of a large-diameter butterfly valve, or due to pipeline stress, valve weight (particularly significant for large valves), a strong lateral bending moment will be generated on the valve stem. Existing patents only cover tests parallel to the valve stem axis, which is incomplete.

[0004] In addition, the existing valve bending moment testing equipment lacks flexibility in its test counterweight and loading structure, and cannot be adapted to the self-weight of different valves and the weight of pipeline combinations, thus limiting the test efficiency and versatility. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that bending moment testing cannot comprehensively measure both the test parallel to the valve stem axis and the test perpendicular to the valve stem axis. At least one of the existing valve bending moment testing devices has the inconvenience of adjusting the test counterweight.

[0006] This invention is implemented as follows: a bending moment testing device includes: two bases, the two bases being distributed at a distance along a straight line; two vertical frames fixed on the two bases; an assembly frame disposed on one side of the two bases, the top of the assembly frame having a horizontal extension extending towards the vertical frame; a limiting mechanism disposed on the two vertical frames for fixing pipe fittings and valves from both ends; a bracket disposed on the top of the vertical frames for supporting the pipe fittings; an adjustable counterweight mechanism disposed on the assembly frame and adjustable in height and position for applying adaptive bending moment loads to the pipe fittings; and a water circulation filtration mechanism disposed below the assembly frame for injecting water into the pipe fittings and recovering leaked water.

[0007] Preferably, the limiting mechanism includes: a limiting shell fixed to the bracket by screws, wherein the limiting shell clamps the pipe fitting when it is closed with the bracket; and a second inner pad is provided inside both the bracket and the limiting shell.

[0008] Preferably, the counterweight mechanism includes: two reels rotatably mounted on the assembly frame via four bearing seats arranged in pairs; a motor fixed to the bottom of the horizontal extension; a transmission rod, the two ends of which are fixedly connected to the opposite ends of the two reels via couplings; two meshing bevel teeth fixed to the output shaft of the motor and the transmission rod; a retractable steel wire rope wound on the reels; and a loading mechanism installed at the end of the steel wire rope for applying a test force to the pipe fitting.

[0009] Preferably, the loading mechanism includes: a hook fixed to the bottom end of the wire rope; a hanging ring hung on the hook; a placement shell fixedly connected to the bottom of the hanging ring; a replaceable counterweight block disposed inside the placement shell; a slot provided on the side wall of the placement shell; a retaining shell fixed to the bottom of the placement shell and cooperating with the pipe fitting; and a first inner pad disposed between the retaining shell and the pipe fitting.

[0010] Preferably, the water circulation filtration mechanism includes: a water tank disposed between two bases; two water pumps disposed on both sides of the water tank; two electric telescopic rods fixed at both ends of the top of the water tank; two connecting plates fixed on the push rods of the two electric telescopic rods; two plugs fixedly connected to the two connecting plates via connecting blocks, the two plugs being adapted to corresponding pipe fitting ports; a water pump pipe fixedly connected to the water pump inlet and communicating with the water tank; and a telescopic pipe fixedly connected to the water pump outlet and passing through the plugs.

[0011] Preferably, the water circulation filtration mechanism further includes: a water receiving shell disposed on the top of the water tank; a housing that communicates with the center of the bottom of the water receiving shell through a first conduit; a second conduit that is fixedly connected to the bottom of the housing and communicates with the top of the water tank; a detachable filter box disposed within the housing; and a filter plate disposed within the filter box.

[0012] Preferably, the water tank is provided with a water inlet; the water inlet is provided with a removable cover plate for replenishing the water tank with the water required for the test.

[0013] Preferably, both the first inner pad and the second inner pad are arc-shaped and made of rubber. A guide plate is fixed on the assembly frame. The guide plate has a through hole for the steel wire rope to pass through. A protective tube is installed in the through hole. A shielding door is provided on the assembly frame to shield the motor, reel, and transmission rod.

[0014] Preferably, the counterweight mechanism further includes: a reciprocating lead screw, the reciprocating lead screw including a smooth rod in the middle and two threaded sections at both ends, the two threaded sections being rotatably mounted on the assembly frame via two bearing seats; two guide blocks threaded onto the two threaded sections; a guide rod fixed between the two bearing seats and passing through the guide blocks; a guide hole provided on the guide block for a steel wire rope to pass through; two pulleys fixed on the transmission rod and the smooth rod respectively; and a transmission belt sleeved between the two pulleys.

[0015] Compared with related technologies, the bending moment testing device provided by the present invention has the following advantages: One set of equipment can complete bending moment tests parallel to the valve stem axis and bending moment tests perpendicular to the valve stem axis. The overall support frame of the device is built by the base, vertical frame and assembly frame. The limiting mechanism on the vertical frame realizes the stable bearing and limiting of different specifications of pipe fittings and valve assemblies. With the adjustable counterweight mechanism, the load height and position can be flexibly adjusted. The counterweight can be replaced according to different test requirements and four-point bending moment load can be applied simultaneously, which solves the problem of insufficient flexibility of counterweight and loading structure in traditional valve bending moment test devices. Attached Figure Description

[0016] Figure 1This is a front view structural schematic diagram of a bending moment testing device provided by the present invention; Figure 2 This is a schematic diagram of the front cross-sectional structure of a bending moment testing device provided by the present invention; Figure 3 for Figure 2 An enlarged structural diagram of part A shown in the figure; Figure 4 for Figure 2 An enlarged structural diagram of part B shown in the figure; Figure 5 for Figure 2 An enlarged structural diagram of section C shown in the figure; Figure 6 for Figure 2 An enlarged structural diagram of part D shown in the figure; Figure 7 for Figure 2 An enlarged structural diagram of part E shown in the figure; Figure 8 This is a schematic diagram of the guide block in this invention; Figure 9 This is a schematic diagram of the filter box in this invention; Figure 10 This is a schematic diagram of the present invention under test conditions perpendicular to the valve stem axis; Reference numerals: 1. Base; 2. Vertical frame; 3. Bracket; 4. Limiting shell; 5. Pipe fitting; 6. Valve; 7. Assembly frame; 8. Clamping case; 9. Placement shell; 10. Counterweight; 11. Reel; 12. Wire rope; 13. Hook; 14. Hanging ring; 15. Motor; 16. Transmission rod; 17. Bevel gear; 18. Plug; 19. Electric telescopic rod; 20. Connecting plate; 21. Water tank; 22. Water pump; 23. Pumping unit 24. Telescopic pipe; 25. Water inlet shell; 26. Shell; 27. First conduit; 28. Second conduit; 29. ​​Filter box; 30. Filter plate; 31. Reciprocating screw; 32. Guide block; 33. Guide rod; 34. Pulley; 35. Transmission belt; 36. Guide plate; 37. Shielding door; 38. Water inlet; 39. Cover plate; 40. First inner pad; 41. Second inner pad; 42. Buckle; 43. Moment plate. Detailed Implementation

[0017] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0018] This invention provides a bending moment test detection device, such as... Figure 1-9 As shown, the bending moment test device includes: two bases 1, which are distributed at a distance along a straight line; two vertical frames 2 fixed on the two bases 1; an assembly frame 7 disposed on one side of the two bases 1, the top of the assembly frame having a horizontal extension extending towards the vertical frame; a limiting mechanism disposed on the two vertical frames 2 for fixing the pipe fitting 5 and valve 6 from both ends; a bracket 3 disposed on the top of the vertical frame for supporting the pipe fitting; an adjustable counterweight mechanism disposed on the assembly frame 7 and adjustable in height and position for applying an adaptive bending moment load to the pipe fitting 5; and a water circulation filtration mechanism disposed below the assembly frame 7 for injecting water into the pipe fitting 5 and recovering leaked water.

[0019] In a further preferred embodiment of the present invention, the limiting mechanism includes: a limiting shell 4 fixed to the bracket 3 by screws, wherein the limiting shell clamps the pipe fitting when it is closed with the bracket; and a second inner pad 41 is provided inside both the bracket 3 and the limiting shell 4.

[0020] In this embodiment, before the bending moment type test of the pipe fitting 5 and the valve 6, the bracket 3 is first installed securely in the preset position of the vertical frame 2. Then, the second inner pad 41 is laid on the bearing surface of the bracket 3 and the inner side of the limiting shell 4 respectively. Then, the spacing of the bracket 3 is adjusted according to the outer diameter of the pipe fitting 5 to prepare for the subsequent placement of the pipe fitting 5 and valve 6 assembly.

[0021] The assembly of pipe fitting 5 and valve 6 is hoisted above the bracket 3 and slowly lowered so that pipe fitting 5 lands smoothly in the bearing area of ​​the bracket 3. Then, the limiting shell 4 is fixed to the bracket 3 with screws, so that the limiting shell 4 and the bracket 3 form a wrapping and limiting structure for pipe fitting 5. The valve 6 is fixed to the adjacent ends of the two pipe fittings 5 ​​with bolts. The second inner pad 41 is attached to the outer wall of pipe fitting 5, thus completing the fixation of the test piece and providing a stable foundation for the subsequent application of bending moment load. During the test, the bracket 3 can reliably support the assembly of pipe fitting 5 and valve 6, preventing displacement of the assembly due to its own weight. The limiting shell 4 can restrict the lateral sway of pipe fitting 5, ensuring the positional stability of the test piece when bending moment load is applied. At the same time, the second inner pad 41 can buffer the contact stress between the bracket 3, the limiting shell 4 and pipe fitting 5, reducing the possibility of impact damage to the surface of pipe fitting 5, providing a guarantee for the smooth conduct of the test, and can also adapt to the limiting requirements of pipe fittings of different specifications, improving the adaptability of the device.

[0022] In a further preferred embodiment of the present invention, the counterweight mechanism includes: two reels 11 rotatably mounted on the assembly frame 7 via four bearing seats arranged in pairs; a motor 15 fixed to the bottom of the horizontal extension; a transmission rod 16, the two ends of which are fixedly connected to the opposite ends of the two reels 11 via couplings; two meshing bevel teeth 17 fixed to the output shaft of the motor 15 and the transmission rod 16; a retractable steel wire rope 12 wound on the reels 11; and a loading mechanism installed at the end of the steel wire rope for applying a test force to the pipe fitting.

[0023] In this embodiment, based on the load position requirements converted from the bending moment value required for the test, the motor 15 in the assembly frame 7 is started. The output shaft of the motor 15 rotates, driving the meshing bevel gear 17 to rotate, causing the transmission rod 16 to rotate accordingly. The transmission rod 16 further drives the two reels 11 at both ends to rotate synchronously. During the rotation of the reels 11, the wire rope 12 is wound up and unwound, thereby driving the loading mechanism connected to the wire rope 12 to adjust its height until the loading mechanism is adjusted to the pre-loaded position of the pipe fitting 5. The counterweight mechanism, through the linkage of motor 15, bevel gear 17 and transmission rod 16, can drive two reels 11 to synchronously wind and unwind the wire rope 12, making the height adjustment of the loading mechanism more synchronized and ensuring the balance of the four-point bending load. At the same time, the cooperation between reels 11 and wire rope 12 can realize the flexible adjustment of the height of the loading mechanism, which can adapt to the test height requirements of different specifications of pipe fittings and valve assemblies, providing adaptable load height conditions for the test, and improving the test versatility of the device to a certain extent.

[0024] In a further preferred embodiment of the present invention, the loading mechanism includes: a hook 13 fixed to the bottom end of the wire rope 12; a hanging ring 14 hanging on the hook 13; a placement shell 9 fixedly connected to the bottom of the hanging ring 14; a replaceable counterweight 10 disposed inside the placement shell 9; a slot 42 provided on the side wall of the placement shell; a retaining shell 8 fixed to the bottom of the placement shell 9 and cooperating with the pipe fitting; and a first inner pad 40 disposed between the retaining shell 8 and the pipe fitting.

[0025] In this embodiment, the clamp refers to an open clamp that can enclose at least the upper surface of the pipe fitting. A test parallel to the valve stem axis can be performed first. After the transmission components such as the reel 11 and the wire rope 12 are debugged, the first inner pad 40 is laid on the inside of the clamp 8, and then the hanging ring 14 is hung on the hook 13 at the bottom of the wire rope 12, so that the placement shell and the wire rope 12 are connected. Then, according to the test bending moment requirements of the DN500 pipe fitting 5 and valve 6 assembly, the required counterweight is calculated and the corresponding counterweight block 10 is placed in the placement shell 9 to complete the preliminary assembly of the loading component. After the loading mechanism is adjusted to the pre-loaded position of the pipe fitting 5, the clamp 8 is clamped in the designated position of the pipe fitting 5, and the first inner pad 40 is in contact with the outer wall of the pipe fitting 5. At this time, the motor 15 is started to drive the reel 11 to finely adjust the tension of the wire rope 12, so that the weight of the counterweight 10 placed in the shell 9 is converted into a load on the pipe fitting 5. The adaptive bending moment load is applied to the pipe fitting 5 and valve 6 assembly in the form of four-point bending, and the bending moment type test is carried out to verify its deformation resistance and leakage prevention capabilities. Then perform a test perpendicular to the valve stem axis, such as... Figure 10 As shown, the loading mechanism is raised by a wire rope, and a moment disc 43 is installed on the valve stem. The height of the moment disc is matched with the height of the clamp. At this time, the clamp is completely detached from the pipe. One placement shell is pulled close to the moment disc, or two placement shells are pulled close to the moment disc at the same time. The moment disc bears the weight of the placement shell, the counterweight, and the clamp, thereby performing a moment test perpendicular to the valve stem axis.

[0026] This application uses a counterweight to apply force for tests parallel to and perpendicular to the valve stem axis. The advantage is that the force generated by the counterweight (or weights) is directly determined by the weight's mass and gravitational acceleration, providing absolute accuracy. The counterweight can be calibrated by a metrological verification institution, ensuring a complete and clear traceability chain for the force value. Once the counterweight is suspended, the applied force value remains stable over a long period without drifting. This is crucial for long-term continuous testing or creep performance testing. The mechanical loading system has a simple structure, no complex control components, and a low failure rate. Even in the event of an accident, the force value changes relatively slowly, which helps protect the specimen and instrument. The counterweight loading system has a simple structure, relatively low manufacturing and maintenance costs, a visually intuitive loading process, simple and clear force calculation, and low operator training requirements. Because the counterweight's position is fixed, the applied force position on the pipe remains consistent during each bending moment test, ensuring consistent test conditions.

[0027] In a further preferred embodiment of the present invention, the water circulation filtration mechanism includes: a water tank 21 disposed between two bases; two water pumps 22 disposed on both sides of the water tank 21; two electric telescopic rods 19 fixed at both ends of the top of the water tank 21; two connecting plates 20 fixed on the push rods of the two electric telescopic rods 19; two plugs 18 fixedly connected to the two connecting plates 20 by connecting blocks, the two plugs being adapted to corresponding pipe ports; a water pumping pipe 23 fixedly connected to the water inlet of the water pump 22 and connected to the water tank 21; and a telescopic pipe 24 fixedly connected to the water outlet of the water pump 22 and passing through the plugs 18.

[0028] In this embodiment, after the pipe fitting 5 and valve 6 assembly are fixed in place, the two electric telescopic rods 19 on the water tank 21 are activated. The push rods of the two electric telescopic rods 19 extend and retract, causing the two connecting plates 20 to move, so that the two plugs 18 connected to the connecting plates 20 are displaced synchronously until the two plugs 18 are tightly fitted to the port of the pipe fitting 5, thus sealing the port of the pipe fitting 5. Then, the water pump 22 is activated to transport the water in the water tank 21 to the inside of the pipe fitting 5, creating a water pressure environment that simulates the actual working conditions for the test. The combination of water tank 21 and water pump 22 enables the supply of test water, providing the necessary water pressure conditions for verifying the sealing performance of valve 6 under bending moment load, and facilitating the smooth conduct of the test.

[0029] In this embodiment, after the plug 18 has sealed the port of the pipe fitting 5, the water pump 22 is started. The operation of the water pump 22 causes the water in the water tank 21 to enter the water pump 22 through the water pump pipe 23. Then, through the pressurization action of the water pump 22, the water is transported to the telescopic pipe 24. The telescopic pipe 24 adapts its length according to the displacement of the plug 18, so that the water can smoothly enter the sealed pipe fitting 5 until the water pressure inside the pipe fitting 5 reaches the water pressure value required for the test, thereby simulating the actual working water pressure environment of the valve 6. The pumping pipe 23 provides a stable water intake path for the water pump 22, ensuring a continuous supply of test water. The telescopic pipe 24 can be adjusted to expand and contract with the position of the plug 18, adapting to the water delivery needs of plugs 18 with different spacing, and preventing the pipeline from bending or falling off due to displacement. The cooperation of the entire pipeline assembly can realize the directional delivery of test water, creating water pressure conditions that fit the actual working conditions for the pipe fitting 5 and valve 6 assembly, which helps to more accurately verify the sealing performance of valve 6 under bending moment load.

[0030] In a further preferred embodiment of the present invention, the water circulation filtration mechanism further includes: a water receiving shell 25 disposed on the top of the water tank 21; a housing 26 connected to the center of the bottom of the water receiving shell 25 via a first conduit 27; a second conduit 28 fixedly connected to the bottom of the housing 26 and connected to the top of the water tank 21; a detachable filter box 29 disposed within the housing 26; and a filter plate 30 disposed within the filter box 29. The filter box 29 and the filter plate 30 are used to filter impurities in the seepage water, thereby achieving purification and recycling of the seepage water.

[0031] In this embodiment, if water seepage occurs at the connection between pipe 5 and valve 6 during the bending moment test, the seepage water will drip into the water receiving shell 25 and then flow into the shell 26 through the first conduit 27. The filter box 29 and filter plate 30 in the shell 26 will filter the seepage water and intercept the impurities in the seepage water. The filtered water will then flow back to the water tank 21 through the second conduit 28, thereby completing the recovery and purification of the seepage water. The water collection shell 25 can collect the seepage water during the test, avoiding the seepage water from polluting the test site; the filter box 29 and filter plate 30 can purify the seepage water, reducing the impact of impurities in the water on the water tank 21 and water pump 22, and the filter box 29 is detachable, which is convenient for cleaning or replacing the filter plate 30 later; the second conduit 28 can return the purified seepage water to the water tank 21, realizing the recycling of test water and reducing the water cost of the test to a certain extent.

[0032] In a further preferred embodiment of the present invention, a water inlet 38 is provided on the water tank 21; a detachable cover plate 39 is provided inside the water inlet 38 for replenishing the water required for the test into the water tank 21.

[0033] In this embodiment, when the water level in the water tank 21 is detected to be lower than the preset standard during the test, or when the initial water volume is found to be insufficient before the test, the cover plate 39 is removed from the water inlet 38, and the required clean water for the test is injected into the water tank 21 through the water inlet 38. After the water level in the water tank 21 reaches the specified height, the cover plate 39 is reinstalled at the water inlet 38 to complete the water replenishment operation of the water tank 21, so that the water circulation filtration mechanism can continuously supply water for the test. The water inlet 38 provides a convenient water replenishment channel for the water tank 21, which can replenish the water lost during the test in a timely manner and ensure the continuous and stable operation of the water circulation filtration mechanism. The detachable cover plate 39 can effectively block the water inlet 38, preventing water in the water tank 21 from splashing out of the water inlet 38 during the test. At the same time, it can also prevent external impurities from entering the water tank 21 through the water inlet 38 and contaminating the test water, thus providing a water supply guarantee for the smooth conduct of the test.

[0034] In a further preferred embodiment of the present invention, the first inner pad 40 and the second inner pad 41 are both arc-shaped and made of rubber. A guide plate 36 is fixed on the assembly frame 7. The guide plate 36 has a through hole through which the wire rope 12 can pass. A protective tube is provided in the through hole. A blocking door 37 is provided on the assembly frame 7 to block the motor 15, the reel 11 and the transmission rod 16.

[0035] In this embodiment, when the pipe 5 is fixed and a bending moment load is applied, the second inner pad 41 is in contact with the outer wall of the pipe 5. After the clip 8 is clipped onto the pipe 5, the first inner pad 40 simultaneously contacts the pipe 5, thus protecting the pipe 5. During the process of the reel 11 winding and unwinding the wire rope 12, the wire rope 12 moves along the protective tube in the through hole of the guide plate 36, while the shielding door 37 is always in a closed state, thus shielding and protecting the motor 15, reel 11 and transmission rod 16 in the assembly frame 7. In this embodiment, after the motor 15 is started, the power is transmitted to the transmission rod 16 through the bevel gear 17, which drives the two sets of reels 11 to rotate synchronously, so that the two sets of wire ropes 12 are wound and unwound synchronously, which in turn drives the two sets of hooks 13 and hanging rings 14 to rise and fall synchronously, so that the chuck 8 can apply load synchronously at preset positions on both sides of the pipe fitting 5. According to the test requirements of four-point bending, the pipe fitting 5 and valve 6 assembly are subjected to a balanced bending moment, thus completing the load application stage of the bending moment type test. The symmetrical arrangement of the two sets of components enables synchronous loading of the pipe 5, allowing the bending moment load to be applied evenly to the test specimen, avoiding uneven stress on the test specimen due to unilateral loading, which would affect the accuracy of the test data. The synchronous retraction and extension actions ensure the stability of the loading process and reduce the possibility of test specimen skewing. At the same time, the symmetrical structure can also distribute the load pressure of individual components, extend the service life of the components, and provide structural protection for the reliability of the test.

[0036] To further improve the performance of this device, in addition to the above-mentioned solutions, this solution also includes the following embodiments: In another embodiment of the present invention, the counterweight mechanism further includes: a reciprocating screw 31, the reciprocating screw including a smooth rod in the middle and two threaded sections at both ends, the two threaded sections being rotatably mounted on the assembly frame 7 via two bearing seats; two guide blocks 32 threaded onto the two threaded sections; a guide rod 33 fixed between the two bearing seats and passing through the guide blocks 32; a guide hole provided on the guide block 32 for the wire rope 12 to pass through; two pulleys 34 fixed on the transmission rod 16 and the smooth rod respectively; and a transmission belt 35 sleeved between the two pulleys 34, the transmission rod 16 being linked with the reciprocating screw 31 via the pulleys 34 and the transmission belt 35, which can realize the synchronous action of the reel 11 winding and unwinding the wire rope 12 and guiding the guide blocks 32.

[0037] In this embodiment, after the motor 15 is started, the power drives the transmission rod 16 to rotate via the bevel gear 17. While the transmission rod 16 drives the two sets of reels 11 to synchronously wind and unwind the wire rope 12, it also drives the reciprocating screw 31 to rotate via the pulley 34 and the transmission belt 35, causing the guide block 32 to reciprocate along the guide rod 33. This allows the wire rope 12 to be synchronously guided through the guide hole, ensuring that the wire rope 12 always maintains the preset traction angle. This, together with the clamp 8, completes the application of bending moment load to the pipe fitting 5. The linkage design of the transmission rod 16 and the reciprocating screw 31 enables the synchronous movement of the reel 11 winding and unwinding the wire rope 12 and the guide block 32 guiding, improving the coordination of the loading process. The reciprocating movement of the guide block 32 can effectively guide the wire rope 12, preventing the wire rope 12 from deviating or tangling during winding and unwinding, and ensuring the stability of the load application. The guide rod 33 can limit the rotation of the guide block 32, ensuring the accuracy of its movement trajectory, providing reliable guiding support for bending moment loading at different positions, and further improving the test adaptability of the device.

[0038] In this embodiment, during the bending moment type test of valve 6, the two ends of the two pipe fittings 5 ​​and valve 6 assembly are first placed in the limiting mechanism on the vertical frame 2. The assembly is supported by the bracket 3, and the limiting shell 4 is fixed by screws. The second inner pad 41 is used to achieve stable limiting of pipe fitting 5. Then, the water circulation filtration mechanism under the assembly frame 7 is started, and the electric telescopic rod 19 is controlled to drive the connecting plate 20 to move, so that the plug 18 seals the port of pipe fitting 5 where valve 6 is not installed. Then, the water pump 22 draws water from the water tank 21 and delivers it to the inside of pipe fitting 5 through the telescopic pipe 24 to simulate the water pressure environment of the actual water supply condition. Based on the bending moment value required by EN1074 standard, the load value to be applied is calculated, and a counterweight block 10 of the corresponding weight is placed into the placement shell 9 of the adjustable counterweight mechanism; the motor 15 is started, and the transmission rod 16 is driven to rotate through the bevel gear 17, so that the reel 11 winds up and unwinds the wire rope 12, the height of the clamp 8 is adjusted and it is clamped in the preset position of the pipe fitting 5, and at the same time, the transmission rod 16 drives the reciprocating screw 31 to rotate through the pulley 34 and the transmission belt 35, so that the guide block 32 moves along the guide rod 33 to guide the wire rope 12, and apply the adaptive bending moment load to the pipe fitting 5 and valve 6 assembly in the form of four-point bending, and carry out type test; During the test, the water receiving shell 25 can collect the water seeping from the connection between the pipe fitting 5 and the valve 6. The seeping water enters the shell 26 through the first conduit 27, and after being filtered by the filter plate 30 in the filter box 29, it flows back to the water tank 21 through the second conduit 28, realizing the recycling of water resources. The adjustable counterweight mechanism of this device can replace the counterweight 10 and adjust the loading position according to the weight of different specifications of pipe fittings and valve assemblies and the test bending moment requirements. Compared with traditional devices, it improves adaptability and helps to improve test efficiency. At the same time, the inner pad in the limiting mechanism can reduce the impact damage to the pipe fitting 5 during the test, ensure the stability of the test process, and provide reliable testing conditions for verifying the structural strength and sealing performance of large-diameter valves under complex working conditions.

[0039] In summary, compared with related technologies, the overall support frame of the device is constructed by the base 1, the vertical frame 2, and the assembly frame 7. The limiting mechanism on the vertical frame 2 enables stable bearing and limiting of the assembly of pipe fittings 5 ​​and valves 6 of different specifications. With the adjustable counterweight mechanism, the load height and position can be flexibly adjusted. The counterweight 10 can be replaced according to different test requirements and four-point bending moment load can be applied simultaneously. This solves the problem of insufficient flexibility in the counterweight and loading structure of traditional valve bending moment test devices.

[0040] It is worth noting that the adjustable counterweight mechanism of this device, with its linkage structure of transmission rod 16, pulley 34, and reciprocating screw 31, differs from traditional single-lifting loading mechanisms. Its innovation lies in achieving synchronous linkage between "load height adjustment" and "wire rope 12 guidance," with the following specific advantages: To avoid load imbalance: Two symmetrically arranged reels 11 synchronously wind up and unwind the wire rope 12 under the drive of the transmission rod 16, which can ensure the synchronous lifting and lowering of the two side clamps 8. The reciprocating screw 31 drives the guide block 32 to move along the guide rod 33, which can correct the traction angle of the wire rope 12 in real time, prevent the clamps 8 from shifting their force points on the pipe 5 due to the wire rope offset, and ensure the uniformity of the four-point bending load. This solves the problem of test data distortion caused by load imbalance in traditional devices. Adaptable to multiple test specimens: The transmission ratio between the transmission rod 16 and the reciprocating screw 31 can be adjusted by replacing the pulley 34. The travel of the guide block 32 can be flexibly adjusted according to the force application point position of different DN specification pipe fittings 5. With the replacement counterweight 10, bending moment loading can be achieved for valve and pipe fitting assemblies of multiple specifications such as DN300-DN600, breaking through the limitation of traditional devices that can only adapt to a single specification test specimen.

[0041] The design of the water circulation filtration mechanism not only enables the recycling of test water, but also optimizes it to meet the requirements of EN1074 standard that "the test liquid is water within the operating temperature range" and "tightness testing". Accurate simulation of water pressure environment: The water pump 22 can deliver constant pressure water to the pipe fitting 5 through the telescopic pipe 24, and the water tank 21 can be connected to an external temperature control device (extension interface reserved) to ensure that the temperature of the test water meets the working temperature range requirements of the standard clause 4.4; the plug 18 driven by the electric telescopic rod 19 can be adapted to the port sealing of pipe fittings 5 ​​of different lengths. With the flexible connection of the telescopic pipe 24, the water pressure leakage problem caused by pipeline displacement in the traditional sealing structure is avoided. Leakage monitoring and water quality assurance: The opening size of the water inlet shell 25 is perfectly matched with the flange connection area of ​​the DN500 valve 6, which can collect the leakage liquid in real time. The filter box 29 (with built-in filter plate 30) inside the shell 26 can filter flange gasket debris, pipe corrosion impurities, etc. in the leakage water, preventing impurities from flowing back to the water tank 21 and contaminating the test water. At the same time, the detachable filter box 29 facilitates later maintenance and ensures the long-term stable operation of the water circulation system. The quick-release structure of hook 13 and hanging ring 14 enables quick disassembly and assembly of the housing 8, facilitating the maintenance of the loaded components after testing; the filter box 29 adopts a snap-on installation, which can be disassembled without tools; the water inlet 38 of the water tank 21 is equipped with a cover plate 39, which not only ensures convenient water replenishment but also prevents external pollutants from entering, reducing the later maintenance cost of the device.

[0042] The circuits, electronic components, and modules involved in this invention are all existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon. The content protected by this invention does not involve improvements to the software and methods.

[0043] It should be understood, in the several embodiments provided in this application, that the disclosed apparatus may be implemented in other ways.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not depart from the concept of the present invention. These technical solutions are also within the scope of protection of the present invention.

Claims

1. A bending moment testing device, characterized in that, include: Two bases, the two bases being distributed at a straight interval; Two vertical supports fixed to two bases; An assembly frame is provided on one side of the two bases, the top of the assembly frame having a horizontal extension extending toward the vertical frame; a limiting mechanism is provided on the two vertical frames for fixing the pipe fittings and valves from both ends; a bracket is provided on the top of the vertical frames for supporting the pipe fittings; an adjustable counterweight mechanism is provided on the assembly frame and is adjustable in height and position for applying adaptive bending moment loads to the pipe fittings. A water circulation filtration mechanism, located below the assembly frame, is used to inject water into the pipe fitting and recover leaked water. The counterweight mechanism includes: two reels mounted on the assembly frame via four bearing seats arranged in pairs; a motor fixed to the bottom of the horizontal extension; a transmission rod, with both ends fixedly connected to opposite ends of the two reels via couplings; two meshing bevel teeth fixed to the motor output shaft and the transmission rod; a retractable steel wire rope wound on the reels; and a loading mechanism installed at the end of the steel wire rope to apply a test force to the pipe fitting. The loading mechanism includes: a hook fixed to the bottom end of the steel wire rope; a hanging ring attached to the hook; a placement shell fixedly connected to the bottom of the hanging ring; a replaceable counterweight block disposed within the placement shell; a latch on the side wall of the placement shell; a retaining clip fixed to the bottom of the placement shell and engaging with the pipe fitting; and a first inner pad disposed between the retaining clip and the pipe fitting.

2. The bending moment test detection device as described in claim 1, characterized in that, The limiting mechanism includes: a limiting shell fixed to the bracket by screws, which clamps the pipe fitting when the limiting shell and the bracket are closed; and a second inner pad is provided inside both the bracket and the limiting shell.

3. The bending moment test detection device as described in claim 1, characterized in that, The water circulation filtration mechanism includes: a water tank disposed between two bases; two water pumps disposed on both sides of the water tank; two electric telescopic rods fixed at both ends of the top of the water tank; two connecting plates fixed on the push rods of the two electric telescopic rods; two plugs fixedly connected to the two connecting plates via connecting blocks, the two plugs being adapted to corresponding pipe fitting ports; a water pump pipe fixedly connected to the water pump inlet and communicating with the water tank; and a telescopic pipe fixedly connected to the water pump outlet and passing through the plugs.

4. The bending moment test detection device as described in claim 3, characterized in that, The water circulation filtration mechanism further includes: a water receiving shell disposed on the top of the water tank; a housing that is connected to the center of the bottom of the water receiving shell through a first conduit; a second conduit that is fixedly connected to the bottom of the housing and connected to the top of the water tank; a detachable filter box disposed within the housing; and a filter plate disposed within the filter box.

5. The bending moment test detection device as described in claim 4, characterized in that, The water tank is provided with a water inlet; the water inlet is provided with a removable cover plate for replenishing the water tank with the water required for the test.

6. The bending moment test detection device as described in claim 5, characterized in that, Both the first inner pad and the second inner pad are arc-shaped and made of rubber. A guide plate is fixed on the assembly frame. The guide plate has a through hole for the steel wire rope to pass through. A protective tube is installed in the through hole. A shielding door is installed on the assembly frame to shield the motor, reel and transmission rod.

7. The bending moment test detection device as described in claim 6, characterized in that, The counterweight mechanism further includes: a reciprocating lead screw, which comprises a smooth rod in the middle and two threaded sections at both ends, the two threaded sections being rotatably mounted on the assembly frame via two bearing seats; two guide blocks threaded onto the two threaded sections; a guide rod fixed between the two bearing seats and passing through the guide blocks; a guide hole provided on the guide block for a steel wire rope to pass through; two pulleys fixed on the transmission rod and the smooth rod respectively; and a transmission belt fitted between the two pulleys.

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