A slow closing check valve

Abstract

The application discloses a slow-closing check valve, and relates to the technical field of valves.The slow-closing check valve comprises a valve body and an opening and closing mechanism, the valve body is provided with an inner cavity, the inner cavity is open at both ends, and the inner cavity comprises a rotating cavity in the middle and two channels on both sides; the opening and closing mechanism comprises a main valve clack and a secondary valve clack, the main valve clack is rotationally arranged above one side of the rotating cavity, and the main valve clack opens or closes the channel in a rotating swing mode, the main valve clack is provided with a liquid passing opening, and the secondary valve clack is rotationally arranged above the liquid passing opening and opens or closes the liquid passing opening in a rotating swing mode; wherein the rotation between the secondary valve clack and the main valve clack has a damping effect.The slow-closing check valve has the advantages of effectively relieving water hammer effect, realizing time sequence closing of the main valve clack and the secondary valve clack, and improving the safety of a pipeline system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valves, in particular to a slow-closing check valve. BACKGROUND

[0002] As a key component in fluid conveying system, the core function of check valve is to achieve one-way flow cut-off through the self-weight and medium pressure of the circular valve disc. Swing check valve adopts inclined valve disc design, which keeps open state when medium flows forward, and realizes rapid closure through medium pushing when medium flows backward. However, this traditional structure has defects: when the conveying system encounters pump sudden stop or flow rate sudden drop, the valve disc will be closed instantaneously under the action of medium pressure or gravity, and this sudden flow cut-off behavior will generate severe water hammer effect in the pipeline. The pressure wave formed by water hammer will not only impact the valve body structure, causing sealing failure and component deformation, but also may be transmitted along the pipeline to cause chain damage, and in severe cases, it may cause pipeline explosion, pump damage and other safety accidents. SUMMARY

[0003] The main purpose of the present application is to provide a slow-closing check valve, which has the advantages of effectively alleviating water hammer effect, realizing time sequence closure of main and auxiliary valve discs, and improving the safety of pipeline system.

[0004] To achieve the above purpose, the slow-closing check valve provided by the present application comprises:

[0005] A valve body is provided with an inner cavity, the inner cavity is open at both ends, and the inner cavity comprises a rotating cavity in the middle and two channels on both sides;

[0006] An opening and closing mechanism comprises a main valve disc and an auxiliary valve disc, the main valve disc is rotationally arranged above one side of the rotating cavity to open or close the channel in a rotary swing manner, the main valve disc is provided with a liquid passage, and the auxiliary valve disc is rotationally arranged above the liquid passage to open or close the liquid passage in a rotary swing manner;

[0007] Wherein, the rotation between the auxiliary valve disc and the main valve disc has a damping effect, when the medium in the check valve is in forward flow state, the main valve disc and the auxiliary valve disc are both in open state, when the medium in the check valve is in backward flow state, the main valve disc swings to close the channel due to its own gravity and the change of medium flow direction, and after the main valve disc is closed, the auxiliary valve disc is closed due to the pushing of medium pressure, so that the main valve disc and the auxiliary valve disc are closed in sequence, sudden flow cut-off is avoided, and damage caused by water hammer effect is reduced.

[0008] In an embodiment, the liquid passage is arranged in the middle of the main valve disc.

[0009] In an embodiment, the opening and closing mechanism comprises:

[0010] Two fixed parts, which are located above one side of the rotating cavity, and form a rotating position between the two fixed parts;

[0011] A rotating shaft, which is rotatably arranged in the fixed part;

[0012] A connecting frame, which connects the rotating shaft and the main valve disc, and is located on the side of the main valve disc close to the rotating cavity.

[0013] In an embodiment, the connecting frame comprises:

[0014] A connecting plate, which is connected with the rotating shaft;

[0015] A connecting ring, which is connected with the connecting plate, and the inner ring of the connecting ring is arranged for the auxiliary valve disc, so that the auxiliary valve disc can be smoothly closed or opened;

[0016] Four connecting blocks, which are evenly arranged on the connecting ring, and the connecting blocks connect the main valve disc.

[0017] In an embodiment, the auxiliary valve disc comprises a rotating shaft, the connecting block is provided with a damping cylinder, and the rotating shaft is rotatably arranged in the damping cylinder; or

[0018] The rotating shaft is rotatably connected with the connecting block, and a torsional spring is arranged between the rotating shaft and the connecting block.

[0019] In an embodiment, a recessed table is arranged around the liquid passage, one side of the auxiliary valve disc is provided with a sealing gasket, and the sealing gasket is located in the recessed table when the auxiliary valve disc is in a closed state.

[0020] In an embodiment, a damping structure is arranged between the rotating shaft and the fixed part, which is used to exert a damping effect on the rotation of the rotating shaft when the main valve disc is closed more than half, and to avoid strong impact of the main valve disc on the premise of ensuring the check speed.

[0021] In an embodiment, the opposite sides of the two fixed parts are each provided with a recessed groove, the rotating shaft is rotatably arranged in the recessed groove, there is a gap between the edge of the rotating shaft and the inner wall of the recessed groove, the two ends of the rotating shaft are provided with protruding parts, the inner wall surface of the recessed groove is provided with a damping part, and the protruding part is in contact with the damping part when the main valve disc is closed more than half, so as to exert a damping effect on the rotating shaft.

[0022] In an embodiment, the main valve disc comprises a valve disc body and a sealing ring, the sealing ring is arranged around the edge of the valve disc body, a bumper ring is arranged in one of the passages, and the bumper ring is sealed with the sealing ring.

[0023] In an embodiment, the edge of the sealing ring is provided with a guide slope, and the anti-collision ring is provided with a slope corresponding to the guide slope.

[0024] From the above, the slow closing check valve and the opening and closing mechanism thereof provided by the application can effectively avoid the sudden interruption of the medium flow and significantly reduce the impact caused by the water hammer effect through the time sequence action of the primary valve disc closing first and the secondary valve disc closing second, and have the advantages of simple structure, convenient maintenance, safety and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained according to the structures shown in these drawings without creative labor.

[0026] Figure 1 A perspective structural schematic view of an embodiment of the slow closing check valve provided by the application;

[0027] Figure 2 A sectional view of the opening of the check valve;

[0028] Figure 3 A sectional view of the closing of the check valve;

[0029] Figure 4 An exploded schematic view of the opening and closing mechanism.

[0030] DESCRIPTION OF DRAWINGS

[0031] 1000, slow closing check valve; 1, valve body; 11, rotating cavity; 12, passage; 2, opening and closing mechanism; 21, primary valve disc; 211, sealing ring; 212, liquid passage; 213, recessed platform; 22, secondary valve disc; 221, rotating shaft; 222, torsional spring; 23, fixed part; 231, recessed groove; 232, damping part; 24, rotating shaft; 241, protruding part; 25, connecting frame; 251, connecting plate; 252, connecting ring; 253, connecting block; 3, anti-collision ring.

[0032] The realization of the object, functional features and advantages of the application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0033] With reference to the drawings and the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0034] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directional indications also change accordingly.

[0035] In addition, if the embodiments of the present application involve descriptions such as “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the scope of protection claimed by the present application.

[0036] Please refer to Figures 1 to 4 The application provides a slow-closing check valve 1000, which comprises a valve body 1 and an opening and closing mechanism 2. The valve body 1 is provided with an inner cavity, the inner cavity is open at both ends, and the inner cavity comprises a rotating cavity 11 in the middle and two channels 12 on both sides. The opening and closing mechanism 2 comprises a main valve disc 21 and a secondary valve disc 22, the main valve disc 21 is rotationally arranged above one side of the rotating cavity 11, and opens or closes the channel 12 in a rotary swinging manner, the main valve disc 21 is provided with a liquid passage 212, and the secondary valve disc 22 is rotationally arranged above the liquid passage 212 and opens or closes the liquid passage 212 in a rotary swinging manner. The rotation between the secondary valve disc 22 and the main valve disc 21 has a damping effect, when the medium in the check valve is in a forward flow state, the main valve disc 21 and the secondary valve disc 22 are both in an open state, when the medium in the check valve is in a reverse flow state, the main valve disc 21 swings to close the channel 12 due to its own gravity and the change of the flow direction of the medium, and after the main valve disc 21 is closed, the secondary valve disc 22 is closed due to the pushing of the medium pressure, so that the main valve disc 21 and the secondary valve disc 22 are closed in sequence, sudden flow interruption is avoided, and damage caused by water hammer effect is reduced.

[0037] Specifically, the valve body 1 can be made of cast iron, stainless steel or other corrosion-resistant materials, and the shape of the inner cavity can be designed as circular, square or other geometric shapes according to actual needs. The size of the rotating cavity 11 should ensure that the main valve disc 21 can freely rotate and swing, and the diameter of the two channels 12 can be adjusted according to the medium flow. The main valve disc 21 and the auxiliary valve disc 22 can be made of metal or composite materials, and their weight and size need to be optimized according to the medium pressure. The shape and size of the liquid passage 212 can be adjusted according to the medium flow rate and flow to ensure that the auxiliary valve disc 22 can effectively control the opening and closing of the liquid passage 212. The damping effect can be achieved by setting a damper, a torsional spring 222 or other buffering devices between the auxiliary valve disc 22 and the main valve disc 21 to control the closing speed of the auxiliary valve disc 22.

[0038] Therefore, the technical scheme sets the main valve disc 21 and the auxiliary valve disc 22, and makes them close in turn, effectively alleviating the water hammer effect caused by the rapid closing of the traditional check valve. Among them, the main valve disc 21 first closes the channel 12, and then the auxiliary valve disc 22 slowly closes the liquid passage 212, avoiding the sudden interruption of the medium flow, thereby reducing the impact on the pipeline and the valve. Compared with the prior art, the scheme significantly reduces the damage risk caused by the water hammer effect while ensuring the check function, improves the service life and safety of the valve.

[0039] Please refer to Figures 2 to 4 Further, the present application also proposes that the liquid passage 212 is opened in the middle of the main valve disc 21.

[0040] Specifically, the liquid passage 212 is arranged in the middle of the main valve disc 21, so that the medium flow can be uniformly distributed through the liquid passage 212. As a preferred embodiment, the shape of the liquid passage 212 can be circular, oval or polygonal, and its size is determined according to the size of the main valve disc 21 and the medium flow requirement. For example, the diameter of the liquid passage 212 can be 1 / 3 to 1 / 2 of the width of the main valve disc 21 to ensure sufficient flow area. Further, the edge of the liquid passage 212 can be chamfered or rounded to reduce the resistance of the medium flow. In addition, the central design of the position of the liquid passage 212 helps the auxiliary valve disc 22 to be evenly stressed when closing, avoiding the sealing being not tight or the wear being intensified due to bias. Therefore, the technical scheme sets the liquid passage 212 in the middle of the main valve disc 21, optimizes the medium flow path, and makes the linkage of the main valve disc 21 and the auxiliary valve disc 22 more stable.

[0041] Please refer to Figures 2 to 4Further, the application also proposes that the opening and closing mechanism 2 of the slow closing check valve 1000 comprises two fixed parts 23, a rotating shaft 24 and a connecting frame 25. The two fixed parts 23 are located above one side of the rotating cavity 11 and form rotating positions in between. The rotating shaft 24 is rotatably arranged on the fixed parts 23. The connecting frame 25 connects the rotating shaft 24 and the main valve disc 21 and is located on the side of the main valve disc 21 close to the rotating cavity 11.

[0042] The fixed parts 23 can be made of metal casting or high-strength engineering plastic, and the interval distance thereof needs to be accurately designed according to the swing amplitude of the main valve disc 21. The rotating shaft 24 can be made of stainless steel, and the two ends thereof are rotatably connected with the fixed parts 23 through bearings or shaft sleeves. The connecting frame 25 can be an integrally formed metal frame structure, and the connecting mode thereof with the rotating shaft 24 includes welding, bolt fixing or clamping, and the connecting mode thereof with the main valve disc 21 includes threaded connection or riveting. As a preferred embodiment, a buffer gasket can be arranged between the connecting frame 25 and the main valve disc 21 to reduce the impact during closing.

[0043] Specifically, the cooperation of the fixed parts 23 and the rotating shaft 24 enables the main valve disc 21 to stably rotate and swing around the rotating shaft 24. The connecting frame 25 transmits the rotating motion of the rotating shaft 24 to the main valve disc 21, ensuring that the opening and closing actions of the main valve disc 21 are synchronized with the rotating shaft 24. The connecting frame 25 is located on the side of the main valve disc 21 close to the rotating cavity 11, which can optimize the length of the force arm and reduce the torque required to drive the main valve disc 21 to swing. Thus, while ensuring the reliable opening and closing of the valve, the structure can effectively control the swing speed of the main valve disc 21 and avoid the water hammer effect caused by rapid closing.

[0044] Please refer to Figures 2 to 4 Further, the application also proposes that the connecting frame 25 comprises a connecting plate 251, a connecting ring 252 and four connecting blocks 253. The connecting plate 251 is connected with the rotating shaft 24, the connecting ring 252 is connected with the connecting plate 251, the inner ring of the connecting ring 252 is positioned for the auxiliary valve disc 22 so that the auxiliary valve disc 22 can be smoothly closed or opened, and the four connecting blocks 253 are evenly and spacedly arranged on the connecting ring 252 and connected with the main valve disc 21.

[0045] Specifically, the connecting plate 251 can be stamped or cast from a metal plate, and its thickness is designed to be 3-8 mm according to the force requirement. The connecting ring 252 is preferably an annular steel plate, and its inner diameter is 5-10 mm larger than the diameter of the auxiliary valve disc 22 to ensure sufficient positioning. The connecting blocks 253 can be fixed on the connecting ring 252 by welding or bolt connection, and the number thereof is preferably 4 and evenly distributed at 90°. The connecting mode of each connecting block 253 with the main valve disc 21 can be hinged or rigidly connected. As a preferred embodiment, a buffer gasket can be arranged between the connecting block 253 and the main valve disc 21 to reduce the impact and vibration.

[0046] Thus, the technical scheme realizes reliable transmission of the main valve disc 21 and the rotating shaft 24 by optimizing the structure of the connecting frame 25, and provides sufficient movement space for the auxiliary valve disc 22. The inner ring design of the connecting ring 252 avoids movement interference of the auxiliary valve disc 22, and the uniform distribution of the connecting blocks 253 ensures balanced force of the main valve disc 21. Compared with the prior art, the structure effectively reduces the friction loss of the moving parts and prolongs the service life of the valve under the premise of ensuring the opening and closing function of the valve. Specifically, the modular design of the connecting frame 25 facilitates processing and assembly, and the symmetrical arrangement of the four connecting blocks 253 ensures stable closing of the main valve disc 21 and avoids sealing failure caused by uneven force.

[0047] Please refer to Figures 2 to 4 , further, the application also provides that the auxiliary valve disc 22 comprises a rotating shaft 221, a damping cylinder is arranged on the connecting block 253, and the rotating shaft 221 is rotatably arranged in the damping cylinder; or the rotating shaft 221 is rotatably connected with the connecting block 253, and a torsional spring 222 is arranged between the rotating shaft 221 and the connecting block 253.

[0048] Specifically, the damping cylinder can adopt a hydraulic damping structure, filled with viscous fluid, to achieve the effect of rotational damping through fluid resistance. As another embodiment, the damping cylinder can adopt a magneto-rheological damping structure to adjust the damping force by changing the magnetic field strength. The torsional spring 222 can be made of stainless steel to achieve different damping effects by adjusting the pre-tightening force. The connection between the rotating shaft 221 and the connecting block 253 can adopt a bearing structure to ensure smooth rotation. The inner wall of the damping cylinder can be provided with a wear-resistant coating to prolong the service life.

[0049] Thus, the technical scheme realizes reliable transmission of the main valve disc 21 and the rotating shaft 24 by optimizing the structure of the connecting frame 25, and provides sufficient movement space for the auxiliary valve disc 22. The inner ring design of the connecting ring 252 avoids movement interference of the auxiliary valve disc 22, and the uniform distribution of the connecting blocks 253 ensures balanced force of the main valve disc 21. Compared with the prior art, the structure effectively reduces the friction loss of the moving parts and prolongs the service life of the valve under the premise of ensuring the opening and closing function of the valve. Specifically, the modular design of the connecting frame 25 facilitates processing and assembly, and the symmetrical arrangement of the four connecting blocks 253 ensures stable closing of the main valve disc 21 and avoids sealing failure caused by uneven force.

[0050] Please refer to Figures 2 to 4 , further, the application also provides that a recessed platform 213 is arranged around the liquid passage 212, and a sealing gasket is arranged on one side of the auxiliary valve disc 22, and when the auxiliary valve disc 22 is in the closed state, the sealing gasket is located in the recessed platform 213.

[0051] Specifically, the recessed platform 213 is an annular groove structure formed around the edge of the liquid passage 212, and its depth and width are matched with the size of the sealing gasket. The sealing gasket can be made of elastic sealing materials such as rubber and polytetrafluoroethylene, and is installed on the sealing surface of the secondary valve disc 22 by bonding or mechanical fixing. As a preferred embodiment, the cross-sectional shape of the recessed platform 213 can be designed as a trapezoidal or arc shape to better accommodate the sealing gasket and form multiple sealing lines. In addition, the sealing gasket can have a hollow structure or an internal reinforcing skeleton to balance the elastic deformation ability and structural strength.

[0052] The working principle of the technical scheme is that when the medium backflow causes the primary valve disc 21 to close, the secondary valve disc 22 slowly closes under the action of the medium pressure. During the closing process, the sealing gasket first contacts the edge of the recessed platform 213, and as the secondary valve disc 22 continues to press down, the sealing gasket deforms elastically and is completely embedded in the recessed platform 213. Thus, a three-stage sealing effect is formed: the first stage is realized by the tight contact between the sealing gasket and the side wall of the recessed platform 213 for radial sealing; the second stage is realized by the pressure bonding between the bottom of the sealing gasket and the bottom surface of the recessed platform 213 for axial sealing; and the third stage is maintained by the rebound force generated by the deformation of the sealing gasket. Compared with the flat contact type sealing, this structure can effectively compensate for the processing error, realize reliable sealing under low pressure working condition, and reduce the requirement for the processing precision of the valve disc. By controlling the depth of the recessed platform 213, the sealing contact pressure can also be accurately adjusted to avoid premature aging of the sealing material due to overpressure.

[0053] Please refer to Figures 2 to 4 Further, the application also proposes that a damping structure is arranged between the rotating shaft 24 and the fixing member 23, which is used to exert a damping effect on the rotation of the rotating shaft 24 when the primary valve disc 21 is closed more than half, so as to avoid strong impact of the primary valve disc 21 on the premise of ensuring the check speed.

[0054] The specific implementation modes of the damping structure include but are not limited to the following: the opposite sides of the two fixing members 23 are each provided with a recessed groove 231, the rotating shaft 24 is rotationally arranged in the recessed groove 231, there is a gap between the edge of the rotating shaft 24 and the inner wall of the recessed groove 231, the edges of the two ends of the rotating shaft 24 are provided with protruding portions 241, the inner wall of the recessed groove 231 is provided with damping members 232, and when the primary valve disc 21 is closed more than half, the protruding portions 241 are in contact with the damping members 232 to generate a damping effect on the rotating shaft 24. The damping members 232 can be made of elastic materials such as rubber and polyurethane, and the impact energy can be absorbed by the deformation of the materials. In addition, the damping structure can also adopt an active control mode such as a hydraulic damper or a magnetorheological damper to adjust the damping force in real time according to the closing angle of the primary valve disc 21.

[0055] The technical scheme introduces damping effect in the middle of the closing process of the main valve disc 21, so that the main valve disc 21 is not hindered in the initial stage of rapid closing, ensuring the check response speed; and when approaching complete closing, the damping structure starts to act, slowing down the closing speed, thereby effectively reducing the impact force between the main valve disc 21 and the valve body 1. Compared with the existing technology which simply relies on gravity or spring force for rapid closing, the scheme can ensure timely closing of the valve while significantly reducing the impact of water hammer effect, prolonging the service life of the valve and improving the safety of the system. Specifically, the timing of the intervention of the damping structure is precisely designed, and the damping is started only after the closing angle of the main valve disc 21 exceeds 50%, which avoids the influence of early damping on the closing speed and ensures sufficient buffering effect in the critical stage.

[0056] Please refer to Figures 2 to 4 Further, the opposite side of each of the two fixing members 23 is provided with a recessed groove 231, the rotating shaft 24 is rotatably arranged in the recessed groove 231, there is a gap between the edge of the rotating shaft 24 and the inner wall of the recessed groove 231, the edge of the rotating shaft 24 is provided with a protruding part 241, and the inner wall of the recessed groove 231 is provided with a damping member 232. When the main valve disc 21 is closed more than half, the protruding part 241 contacts the damping member 232 to generate damping effect on the rotating shaft 24.

[0057] The recessed groove 231 is a recessed structure arranged on the inner side of the fixing member 23, used for accommodating the rotating shaft 24 and limiting the radial displacement thereof. The gap between the edge of the rotating shaft 24 and the inner wall of the recessed groove 231 allows the rotating shaft 24 to rotate freely while avoiding direct friction. The protruding part 241 is a protruding structure extending outward from the end of the rotating shaft 24, which can be hemispherical, wedge-shaped or other shapes suitable for contacting the damping member 232. The damping member 232 can be made of elastic materials such as rubber and polyurethane, which can absorb impact energy by deformation. As a preferred embodiment, the damping member 232 can be designed as an arc-shaped sheet structure, matching the motion trajectory of the protruding part 241.

[0058] The technical scheme sets damping structure between the rotating shaft 24 and the fixing member 23 to generate buffering effect in the late stage of closing of the main valve disc 21. Specifically, when the closing angle of the main valve disc 21 exceeds 50%, the protruding part 241 on the rotating shaft 24 starts to contact the damping member 232, and as the closing angle increases, the contact pressure gradually increases, thereby forming a progressive damping effect. In this way, the valve is ensured to respond quickly in the initial stage of reverse flow of the medium, and the impact speed in the final stage of closing is effectively slowed down. Compared with the prior art, the scheme optimizes the design of the mechanical structure, significantly reduces the impact force when the valve disc is closed without affecting the check function, thereby reducing the damage caused by water hammer effect.

[0059] Please refer to Figures 2 to 4Further, the application further provides that the main valve disc 21 of the slow closing check valve 1000 comprises a valve disc body and a sealing ring 211, the sealing ring 211 is arranged around the edge of the valve disc body, the passage 12 is provided with a bump ring 3, and the bump ring 3 is sealed with the sealing ring 211. Wherein, the edge of the sealing ring 211 is provided with a guide slope, and the bump ring 3 is provided with a slope corresponding to the guide slope.

[0060] Specifically, the sealing ring 211 can be made of elastic materials such as rubber and polytetrafluoroethylene, and is fixed on the edge of the valve disc body by vulcanization or mechanical pressing. The bump ring 3 is preferably made of metal and is fixed on the inner wall of the passage 12 by screw connection or welding. The inclination angle of the guide slope and the slope of the bump ring 3 is recommended to be 15-45 degrees, and the angle design can realize gradual contact sealing. As a preferred embodiment, the sealing ring 211 can be designed as a V-shaped section, and the lip part thereof forms a line contact sealing with the slope of the bump ring 3. In addition, the slope of the bump ring 3 can be provided with a wear-resistant coating, such as a tungsten carbide coating, to prolong the service life.

[0061] Therefore, the technical scheme realizes gradual contact during the closing process of the main valve disc 21 by the cooperation of the guide slope and the slope, effectively buffers the impact force between the valve disc and the valve body 1. When the medium flows reversely, the main valve disc 21 starts to close under the action of gravity, the guide slope of the sealing ring 211 first makes slight contact with the slope of the bump ring 3, and as the closing stroke increases, the contact area gradually increases until complete sealing. Compared with the flat contact mode, this structure can significantly reduce the impact noise at the moment of closing, and improve the sealing reliability through the self-centering effect of the slope. The angle design of the guide slope can also guide the flow of the medium and reduce the erosion damage of the sealing surface by turbulence.

[0062] Please refer to Figures 2 to 4 Further, the application further provides that the edge of the sealing ring 211 is provided with a guide slope, and the bump ring 3 is provided with a slope matched with the guide slope. The technical scheme realizes gradual contact during the closing process of the main valve disc 21 by setting the guide slope and the slope of the bump ring 3. When the main valve disc 21 swings to the closing position, the guide slope of the sealing ring 211 first contacts the slope of the bump ring 3, and as the valve disc continues to move, the contact area gradually increases until complete sealing. This design effectively avoids the instantaneous impact generated by traditional flat contact, and decomposes the closing impact force into axial and radial components through the slope guiding effect, which significantly reduces the impact noise and wear between the valve disc and the valve seat.

[0063] The above description is only an exemplary embodiment of the application, and does not limit the patent scope of the application, and any equivalent structural transformation made by using the content of the application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the application.

Claims

1. A slow closing check valve characterized by, The slow closing check valve comprises: a valve body provided with an inner cavity, the inner cavity being open at both ends and comprising a rotating cavity in the middle and two channels on both sides; an opening and closing mechanism comprising a main valve disc and a secondary valve disc, the main valve disc being rotatably arranged above one side of the rotating cavity to open or close the channels in a rotary swing manner, the main valve disc being provided with a liquid passage, and the secondary valve disc being rotatably arranged above the liquid passage to open or close the liquid passage in a rotary swing manner; wherein the rotation between the secondary valve disc and the main valve disc has a damping effect, the main valve disc and the secondary valve disc are both in an open state when the medium in the check valve is in a forward flow state, the main valve disc swings to close the channels due to its own gravity and the change of the flow direction of the medium when the medium in the check valve is in a reverse flow state, the secondary valve disc is closed due to the pushing of the medium pressure after the main valve disc is closed, the main valve disc and the secondary valve disc are closed in succession, sudden flow interruption is avoided, and damage caused by water hammer effect is reduced; the opening and closing mechanism comprises two fixing members, a rotating shaft and a connecting frame, the fixing members are arranged above one side of the rotating cavity, a rotating position is formed between the two fixing members, the rotating shaft is rotatably arranged in the fixing members, the connecting frame connects the rotating shaft and the main valve disc, and the connecting frame is arranged on the side of the main valve disc close to the rotating cavity; the connecting frame comprises a connecting plate, a connecting ring and four connecting blocks, the connecting plate is connected with the rotating shaft, the connecting ring is connected with the connecting plate, the inner ring of the connecting ring is provided with a position for the secondary valve disc to smoothly close or open, and the four connecting blocks are uniformly and spacedly arranged on the connecting ring and connected with the main valve disc; the secondary valve disc comprises a rotating shaft, a damping cylinder is arranged on the connecting block, and the rotating shaft is rotatably arranged in the damping cylinder; or the rotating shaft is rotatably connected with the connecting block, and a torsional spring is arranged between the rotating shaft and the connecting block.

2. The slow closing check valve of claim 1, wherein the liquid passage is arranged in the middle of the main valve disc.

3. The slow closing check valve of claim 1, wherein a recessed platform is arranged around the liquid passage, one side of the secondary valve disc is provided with a sealing gasket, and the sealing gasket is arranged in the recessed platform when the secondary valve disc is in a closed state.

4. The slow closing check valve of claim 1, wherein a damping structure is arranged between the rotating shaft and the fixing member, the damping structure is used to apply a damping effect to the rotation of the rotating shaft when the main valve disc is closed by more than half, and the damping structure can avoid strong impact of the main valve disc on the premise of ensuring the check valve speed.

5. The slow closing check valve of claim 4, wherein the opposite sides of the two fixing members are both provided with recessed grooves, the rotating shaft is rotatably arranged in the recessed grooves, there is a gap between the edge of the rotating shaft and the inner wall of the recessed groove, the ends of the rotating shaft are provided with protruding portions, and the inner wall surface of the recessed groove is provided with a damping member, the protruding portions are in contact with the damping member when the main valve disc is closed by more than half to generate a damping effect on the rotating shaft.

6. The slow closing check valve of claim 1, wherein the main valve disc comprises a valve disc body and a sealing ring, the sealing ring is arranged around the edge of the valve disc body, a collision-preventing ring is arranged in one of the channels, and the collision-preventing ring is sealed with the sealing ring.

7. The slow closing check valve of claim 6, wherein the edge of the sealing ring is provided with a guide inclined surface, and the collision-preventing ring is provided with an inclined surface corresponding to the guide inclined surface.

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