Micro-open low-flow-resistance swing check valve

Abstract

The invention relates to the technical field of fluid machinery, in particular to a slightly-opened low-flow-resistance swing check valve which comprises a valve body, a valve rod, a valve rod, a valve rod, a valve rod, a valve rod and a valve rod. The valve clack assembly is installed in the valve cavity and comprises a valve plate, a gravity balance body and a balance weight mechanism. Wherein one end of the valve plate is rotationally connected with the side wall of the valve cavity and is connected with the gravity balance body; the gravity balance body and the rotating axis of the valve plate are eccentrically arranged, and the gravity balance body can drive the valve plate to rotate in the direction away from the flow inlet channel; the balance weight mechanism is installed on the rotating path of the valve plate, can rotate along a preset axis and is limited to the side, away from the flow inlet channel, of the valve plate. In the installation state, the counterweight mechanism can limit the opening angle of the valve plate. The overflow capacity of the valve can be fully guaranteed, and meanwhile the situation that the opening degree is insufficient or the valve clack flutters is avoided.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery technology, specifically to a micro-opening, low-flow-resistance swing check valve. Background Technology

[0002] Check valves are key components in fluid piping systems of nuclear power plants, thermal power plants, and petrochemical industries. They allow fluid to flow freely in one direction and automatically prevent flow in the opposite direction, thus avoiding backflow. Among the many types of check valves, swing check valves are widely used due to their simple structure, reliable operation, and wide range of applications.

[0003] The working principle of a conventional swing check valve is as follows: When fluid flows in from the valve inlet (below the valve disc), the medium pressure overcomes the weight of the valve disc and the rotational resistance, pushing the valve disc to rotate upward around the axis of rotation and open the valve, allowing the fluid to pass through; when there is no flow or reverse flow (closed): when the inlet pressure decreases or disappears, the valve disc, under the action of its own weight, spring force and the pressure of the reverse fluid, quickly swings back and fits against the valve seat sealing surface, thereby preventing the fluid from flowing back.

[0004] Existing swing check valves have a large projected area when the valve disc is open, creating significant resistance to the fluid passage and resulting in unnecessary system capacity loss. Furthermore, the existing swing check valve's micro-opening control mechanism provides additional closing force by adding a spring. While this spring preload helps with rapid closing, at low flow rates, the spring force becomes an additional resistance that needs to be overcome, making the valve disc prone to unstable micro-opening chattering.

[0005] Therefore, it is necessary to study a micro-opening, low-flow-resistance swing check valve to improve the stability and reliability of fluid pipeline systems. Summary of the Invention

[0006] To address the technical problems of existing check valves, such as high flow resistance and easy chattering under low flow conditions, this invention provides a micro-opening, low-flow-resistance swing check valve. By controlling the opening and closing of the valve disc through a counterweight structure, it can maintain a stable micro-opening state initially, eliminating the need for a reset spring. At low flow rates, the flow of the medium does not affect the valve disc, and when fully open, it exhibits low flow resistance characteristics, avoiding unnecessary system capacity loss and ensuring that the system flow meets requirements. While fully guaranteeing the valve's flow capacity, it avoids insufficient opening or valve disc chattering, thereby improving the stability and reliability of the fluid pipeline system.

[0007] This invention is achieved through the following technical solution:

[0008] This invention provides a micro-opening, low-flow-resistance swing check valve, comprising: a valve body having an inlet channel, a valve cavity, and an outlet channel, the valve cavity being connected to the inlet channel and the outlet channel; a valve disc assembly installed within the valve cavity, comprising a valve plate, a gravity balance body, and a counterweight mechanism; wherein, one end of the valve plate is rotatably connected to the side wall of the valve cavity and connected to the gravity balance body; the gravity balance body is eccentrically positioned relative to the rotation axis of the valve plate and is capable of driving the valve plate to rotate away from the inlet channel; the counterweight mechanism is installed on the rotation path of the valve plate, is capable of rotating along a preset axis, and is limited to the side of the valve plate away from the inlet channel; in the installed state, the counterweight mechanism can limit the opening angle of the valve plate, so that the opening angle of the valve plate is maintained at a set value.

[0009] The present invention provides a micro-opening, low-flow-resistance swing check valve, comprising a valve body, a valve plate, a gravity balance body, and a counterweight mechanism. One end of the valve plate is rotatably connected to the side wall of the valve cavity, and the valve plate is connected to the gravity balance body, with the gravity balance body and the valve plate's rotation axis eccentrically positioned. Simultaneously, the counterweight mechanism is installed on the rotation path of the valve plate and can rotate along a preset axis, confined to the side of the valve plate away from the inlet channel. Thus, the gravity balance body provides an initial opening torque to the valve plate, driving it to rotate away from the inlet channel of the valve body. The counterweight mechanism's limiting action ensures that the valve plate initially maintains a certain opening angle. The valve plate maintains a stable open state under low flow rates, ensuring reliable opening under low pressure differentials and stable operation when not in operation. Under higher forward flow rates, the force of the fluid medium drives the valve plate to rotate, keeping it fully open. This results in low flow resistance when the check valve is fully open, avoiding unnecessary system capacity loss and ensuring the system flow meets requirements. Under the action of the reverse medium, the valve plate loses its downward thrust and closes under the combined force of the counterweight, its own weight, and the reverse medium thrust, ensuring reliable closure of the check valve.

[0010] When the valve plate is open, the initial opening torque is provided by the gravity balance body and the counterweight mechanism limits the opening. It does not need to overcome the preload of the return spring, so that the medium flow at a small opening does not affect the valve disc and maintains stable operation with a slight opening. When the flow is reversed, the valve is closed by the action of the counterweight mechanism, its own weight, and the thrust of the reverse medium. This ensures the reliability of the reverse closing and eliminates the need for life-delay components such as springs. It not only has a long service life and high reliability, but also does not need to overcome additional resistance, thus avoiding the valve disc from experiencing slight opening chatter.

[0011] Therefore, the present invention provides a valve that can maintain a slightly open and stable state at the initial stage, does not require a reset spring, does not affect the valve disc when the medium flow is low, has low flow resistance when fully open, avoids unnecessary system capacity loss, ensures that the system flow meets the requirements, and avoids insufficient opening or valve disc flutter while fully ensuring the valve's flow capacity, thereby improving the stability and reliability of the fluid pipeline system.

[0012] In an optional embodiment of this application, a valve cover is also included, which seals over the upper end of the valve cavity to facilitate the machining of the valve body and the installation of the valve disc assembly within the valve body.

[0013] In an optional embodiment of this application, the valve cover is connected to the valve body by mounting bolts, which facilitates the installation and removal of the valve cover.

[0014] In an optional embodiment of this application, a sealing ring gasket is provided between the valve cover and the valve body. The sealing ring gasket is used to seal the gap between the valve cover and the valve body to ensure the sealing of the valve body cavity.

[0015] In an optional embodiment of this application, a sealing lip weld is provided on the side of the valve body facing the valve cover. Under high fluid pressure, the valve cover and valve body can be welded by self-fusion sealing welding to provide a double seal at the joint between the valve body and the valve cover, thereby further improving the sealing performance of the valve body and ensuring that the valve body can be used in high-pressure pipeline systems.

[0016] In an optional embodiment of this application, the outlet channel has a tapered, gradually expanding structure to reduce the resistance to medium flow.

[0017] In an optional embodiment of this application, a valve seat is further included, which is sealed and inserted into the end of the inlet channel to facilitate high-precision machining of the valve seat.

[0018] In an optional embodiment of this application, the valve seat is welded and fixed to the valve body to ensure the stability of the valve seat installation.

[0019] In an optional embodiment of this application, the side of the valve seat facing the valve plate is a ground surface to ensure that the flatness and roughness of the valve seat sealing surface meet the design requirements, so that the valve plate fits on the valve seat with sufficient sealing performance.

[0020] In an optional embodiment of this application, the valve disc assembly further includes a valve shaft, and the valve plate is rotatably connected to the valve body via the valve shaft, so as to rotatably connect the valve plate within the valve cavity.

[0021] In an optional embodiment of this application, the valve plate assembly further includes a connecting rod, one end of which is rotatably connected to the valve shaft and fixedly connected to the gravity balance body, so as to connect the valve plate to the valve shaft.

[0022] In an optional embodiment of this application, a bushing is provided around the valve shaft. The bushing is made of a self-lubricating material and is located between the valve shaft and the connecting support rod, so as to improve the reliability of the valve plate operation by utilizing the self-lubricating properties of the bushing.

[0023] In an optional embodiment of this application, a connecting shaft is provided in the middle of the valve plate, and the connecting shaft is connected to the connecting support rod through a spherical self-centering structure, so that the valve plate can automatically adapt to the change of valve seat shape and improve the valve seat sealing performance.

[0024] In an optional embodiment of this application, a support platform is provided on the side wall of the valve cavity; the counterweight mechanism includes a counterweight hammer, the hammer handle of the counterweight hammer is rotatably connected to the valve shaft, and the hammer head of the counterweight hammer is limited on the support platform. While ensuring that the counterweight mechanism can rotate with the valve plate, it can limit the opening angle of the valve plate under low flow conditions, thereby ensuring the stability of the valve plate opening under low flow conditions.

[0025] In an optional embodiment of this application, the counterweight hammer head is provided with a support shaft. In the installed state, the support shaft abuts against the support platform to facilitate precise control of the initial position of the counterweight hammer.

[0026] In an optional embodiment of this application, the gravity balance body is adapted with a balance adjustment component, which is made of high-density metal material. This can reduce the size of the gravity balance body and also facilitate the adjustment of the opening torque applied by the gravity balance body to the valve plate.

[0027] In an optional embodiment of this application, the balance adjustment component is made of tungsten alloy, which ensures that the balance adjustment component has sufficient balance adjustment capability while also having sufficient radiation resistance.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] The present invention provides a micro-opening, low-flow-resistance swing check valve, comprising a valve body, a valve plate, a gravity balance body, and a counterweight mechanism. One end of the valve plate is rotatably connected to the side wall of the valve cavity, and the valve plate is connected to the gravity balance body, with the gravity balance body and the valve plate's rotation axis eccentrically positioned. Simultaneously, the counterweight mechanism is installed on the rotation path of the valve plate and can rotate along a preset axis, confined to the side of the valve plate away from the inlet channel. Thus, the gravity balance body provides an initial opening torque to the valve plate, driving it to rotate away from the inlet channel of the valve body. The counterweight mechanism's limiting action ensures the valve plate maintains a certain opening angle in its initial state, ensuring a stable opening state under low flow rates, and reliable opening under low pressure differential conditions. When the valve is fully open, it maintains stable operation without being fully open. However, when the forward flow is large, the force of the fluid medium causes the valve plate to drive the counterweight mechanism to continue rotating, maintaining the fully open state. This ensures that the check valve has low flow resistance when fully open, avoiding unnecessary system capacity loss and ensuring that the system flow meets requirements. Under the action of the reverse medium, the valve plate loses its downward thrust and closes under the combined force of the counterweight mechanism, its own weight, and the reverse medium thrust. This ensures the reliability of the check valve's closure, eliminating the need for lifespan components such as springs. It not only has a long service life and high reliability but also avoids the occurrence of valve disc flutter due to slight opening, thereby improving the stability and reliability of the fluid pipeline system. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] In the attached diagram:

[0032] Figure 1 This is a cross-sectional view of the micro-opening, low-flow-resistance swing check valve provided in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the structure of the micro-opening low-flow-resistance swing check valve after the valve body is cut open, according to an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the valve disc assembly of the micro-opening low-flow-resistance swing check valve provided in an embodiment of the present invention.

[0035] Figure 4 This is a schematic diagram of the micro-opening, low-flow-resistance swing check valve in the micro-opening state provided in an embodiment of the present invention.

[0036] Figure 5This is a schematic diagram of the fully open state of the micro-opening low-flow-resistance swing check valve provided in an embodiment of the present invention.

[0037] Figure 6 This is a schematic diagram of the structure of the micro-opening low-flow-resistance swing check valve provided in the embodiment of the present invention, which is completely closed in check mode.

[0038] The attached figures include reference numerals and their corresponding component names:

[0039] 10-Valve body, 11-Inlet channel, 12-Valve cavity, 13-Outlet channel, 14-Sealing lip weld, 15-Support platform, 20-Valve plate, 21-Connecting shaft, 22-Spherical self-centering structure, 30-Gravity balance body, 40-Counterweight mechanism, 41-Counterweight hammer, 42-Support shaft, 50-Valve cover, 51-Mounting bolt, 52-Sealing ring gasket, 60-Valve seat, 70-Valve shaft, 80-Connecting support rod. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0042] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0043] In the description of the embodiments of this application, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this application is usually placed in when in use, or the orientation or positional relationship that is commonly understood by those skilled in the art. It is only for the convenience of describing this application and simplifying the description, and is not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0044] In the description of this application, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0045] Example

[0046] Combination Figure 1 and Figure 2 This embodiment provides a micro-opening, low-flow-resistance swing check valve, comprising: a valve body 10, having an inlet channel 11, a valve cavity 12, and an outlet channel 13, wherein the valve cavity 12 is connected to the inlet channel 11 and the outlet channel 13; a valve disc assembly, installed within the valve cavity 12, comprising a valve plate 20, a gravity balance body 30, and a counterweight mechanism 40; wherein one end of the valve plate 20 is rotatably connected to the side wall of the valve cavity 12 and connected to the gravity balance body 30; the gravity balance body 30 is eccentrically positioned relative to the rotation axis of the valve plate 20 and is capable of driving the valve plate 20 to rotate away from the inlet channel 11; the counterweight mechanism 40 is installed on the rotation path of the valve plate 20, is capable of rotating along a preset axis, and is limited to the side of the valve plate 20 away from the inlet channel 11; in the installed state, the counterweight mechanism 40 can limit the opening angle of the valve plate 20, so that the opening angle of the valve plate 20 is maintained at a set value.

[0047] Specifically, the valve body 10, as the main structure of the check valve, is used to connect to the system pipeline. Its inlet channel 11 and outlet channel 13 typically employ a full-bore design to reduce media flow resistance. Simultaneously, the outer ends of the inlet channel 11 and outlet channel 13 are generally flanged, bolted, or tapered structures to facilitate connection to the system pipeline. In this embodiment, the outlet channel 13 has a tapered, gradually expanding structure to further reduce media flow resistance.

[0048] The material of the valve body 10 needs to be selected according to the type, pressure and temperature of the working medium. It is usually made of cast iron, cast steel, stainless steel, alloy steel, brass / bronze, etc.

[0049] It is understood that this embodiment also includes a valve seat 60. Generally, the valve seat 60 of the check valve is integrally formed with the valve body 10 (the valve seat 60 is directly machined onto the valve body 10), and the valve body 10 is located at the intersection of the valve cavity 12 and the inlet channel 11. In this embodiment, the valve seat 60 is sealed and inserted into the end of the inlet channel 11 to facilitate high-precision machining of the valve seat 60. Simultaneously, the valve seat 60 is welded and fixed to the valve body 10 to ensure the stability of the valve seat 60 installation.

[0050] In other words, the valve seat 60 adopts a cartridge structure, embedded in the valve body 10 and welded together with it. A hard alloy layer is provided on the sealing surface of the valve seat 60, such as by welding a tungsten-cobalt hard alloy layer onto the sealing surface of the valve seat 60 using a welding process, to improve the sealing life of the valve seat 60. Correspondingly, hard alloy is welded onto the valve disc sealing area to improve the durability of the sealing pair. After welding, the sealing surfaces of the valve seat 60 and valve body 10 are precision machined using a CNC machining center. With the assistance of specialized machining fixtures and controlled machining processes, the dimensional and positional tolerances of the sealing surface of the valve seat 60 and the mounting shaft hole (valve shaft 70 hole) on the valve body 10 are ensured, guaranteeing a complete fit between the valve plate 20 and the sealing surface of the valve seat 60 after closure.

[0051] Furthermore, the side of the valve seat 60 facing the valve plate 20 is a ground surface to ensure that the flatness and roughness of the sealing surface of the valve seat 60 meet the design requirements, so that the valve plate 20 fits on the valve seat 60 with sufficient sealing performance.

[0052] It is understood that this embodiment also includes a valve cover 50, which seals and covers the upper end of the valve cavity 12 to facilitate the machining of the valve body 10 and the installation of the valve disc assembly within the valve body 10.

[0053] Generally, the valve cover 50 is connected to the valve body 10 by mounting bolts 51. That is, the port of the valve cavity 12 in the middle of the valve body 10 is a flange structure, which facilitates the installation and removal of the valve cover 50 and the maintenance of the check valve.

[0054] It is understood that a sealing ring gasket 52 is provided between the valve cover 50 and the valve body 10. The sealing ring gasket 52 is used to seal the gap between the valve cover 50 and the valve body 10 to ensure the sealing of the inner cavity of the valve body 10.

[0055] Based on this, a sealing lip weld 14 is provided on the side of the valve body 10 facing the valve cover 50. That is, the flange sealing part of the valve body 10 is designed with a sealing lip weld, which allows the valve cover 50 and the valve body 10 to be welded together by self-fusion sealing welding under high fluid pressure, so as to achieve double sealing at the joint between the valve body 10 and the valve cover 50, improve the performance of the external sealing structure of the check valve, further improve the sealing performance of the valve body 10, and ensure that the valve body 10 can be used in high-pressure pipeline systems.

[0056] Combination Figure 3 The valve disc assembly further includes a valve shaft 70, and the valve plate 20 is rotatably connected to the valve body 10 via the valve shaft 70, so as to rotatably connect the valve plate 20 in the valve cavity 12.

[0057] Specifically, the valve plate 20 assembly also includes a connecting rod 80, one end of which is rotatably connected to the valve shaft 70 and fixedly connected to the gravity balance body 30, so as to connect the valve plate 20 to the valve shaft 70.

[0058] Accordingly, the gravity balance body 30 is typically connected to the connecting support rod 80 by bolts or directly welded to the connecting support rod 80, such that the center of the gravity balance body 30 is eccentrically positioned relative to the rotation axis of the valve plate 20. In this embodiment, after the valve plate 20 and the gravity balance body 30 are assembled, the overall center is located approximately 2mm horizontally at the center of the valve shaft 70, thus providing an initial opening torque for the valve plate 20.

[0059] Combination Figure 4 The valve chamber 12 has a support platform 15 on its side wall; the counterweight mechanism 40 includes a counterweight 41, the handle of which is rotatably connected to the valve shaft 70, and the head of which is fixed on the support platform 15. This ensures that the counterweight mechanism 40 can rotate with the valve plate 20 while limiting the opening angle of the valve plate 20 under low flow conditions, thus ensuring the stability of the valve plate 20's opening under low flow conditions. In this embodiment, the limiting effect of the counterweight 41 allows the valve plate 20 to initially have an opening angle of approximately 20°.

[0060] The counterweight 41 has a support shaft 42 on its hammer head. In the installed state, the support shaft 42 abuts against the support platform 15 to facilitate precise control of the initial position of the counterweight 41.

[0061] Furthermore, the gravity balance body 30 is equipped with a balance adjustment component (usually a rod-shaped structure). This balance adjustment component is made of a high-density metal, such as tungsten, gold, tantalum, or their corresponding alloys. This reduces the size of the gravity balance body 30 and facilitates adjustment of the opening torque applied to the valve plate 20 by the gravity balance body 30. Thus, by adjusting the position of the balance adjustment component built into the gravity balance body 30, the opening degree of the valve plate 20 in its free state can be adjusted within the range of 0–75°, achieving free-state opening degree adjustment of the valve plate 20.

[0062] Therefore, the center of gravity of the valve disc assembly is located at a certain distance (e.g., 2mm) in the horizontal direction of the center of the valve shaft 70, which provides an initial opening torque for the plate and, through the limiting effect of the counterweight 41, keeps the valve plate 20 in a certain micro-opening angle in the initial state.

[0063] In this embodiment, the balance adjustment component is preferably made of tungsten alloy, which ensures that the balance adjustment component has sufficient balance adjustment capability and sufficient radiation resistance.

[0064] It should be understood that a bushing is provided around the valve shaft 70. The bushing is made of a self-lubricating material and is located between the valve shaft 70 and the connecting support rod 80. This utilizes the self-lubricating properties of the bushing to improve the reliability of the valve plate 20's operation. The bushing can be made of materials such as polytetrafluoroethylene, graphite, or ceramic. In this embodiment, silicon nitride ceramic is used as the bushing material to ensure that the bushing has a sufficient service life.

[0065] Correspondingly, the inner hole of the handle of the counterweight 41 is ground and can rotate freely around the valve shaft 70 without jamming. This ensures that the rotation of the valve shaft 70 and the rotation of the counterweight mechanism 40 do not affect each other, thus guaranteeing the reliable opening of the check valve under low pressure differential and the reliable closing under reverse low pressure differential.

[0066] In other words, the counterweight mechanism 40 is mounted on the valve shaft 70 and can rotate freely around the valve shaft 70. It is suspended on the boss inside the valve body 10, located on the opening side of the valve plate 20 and maintaining a certain distance from the valve plate 20. After the valve plate 20 is opened at a certain angle, the valve plate 20 contacts the counterweight hammer 41 of the counterweight mechanism 40. The direction of gravity of the counterweight hammer 41 is opposite to the opening direction of the valve plate 20, which is conducive to the reverse closing of the valve plate 20 and ensures the reliable closing of the check valve under micro pressure difference.

[0067] In addition, a connecting shaft 21 is provided in the middle of the valve plate 20. The connecting shaft 21 is connected to the connecting support rod 80 through a spherical self-centering structure 22, so that the valve plate 20 can automatically adapt to the shape changes of the valve seat 60, thereby improving the sealing performance of the valve seat 60. At the same time, the valve plate 20 adopts a planar sealing structure, and its sealing dimension is larger than the sealing surface of the valve seat 60. Under any circumstances, the sealing surface of the valve plate 20 can completely cover the sealing surface of the valve seat 60, thereby improving the sealing performance of the valve seat 60.

[0068] In summary, the micro-opening, low-flow-resistance swing check valve provided in this embodiment has a valve plate 20 rotatably connected to the side wall of the valve cavity 12 at one end. The valve plate 20 is connected to a gravity balance body 30, and the gravity balance body 30 is eccentrically positioned relative to the rotation axis of the valve plate 20. A counterweight 41 is mounted on the rotation path of the valve plate 20 and can rotate along a preset axis, confined to the side of the valve plate 20 away from the inlet channel 11. Thus, the gravity balance body 30 provides an initial opening torque to the valve plate 20, driving it to rotate away from the inlet channel 11 of the valve body 10. The counterweight mechanism 40 limits the valve plate 20, ensuring it maintains a certain opening angle initially. When the forward flow rate is large, the force of the fluid medium causes the valve plate 20 to drive the counterweight mechanism 40 to continue rotating.

[0069] Combination Figure 4In the initial slightly open state, the center of gravity of the valve disc assembly is located about 2mm horizontally in the center line of the valve shaft 70. In the initial state without external force (no medium flow), the torque MG formed by the gravity of the valve disc and the gravity balance body 30 is in the direction of valve disc opening. Under the action of the driving torque MG, the valve shaft 70 is sufficient to drive the valve plate 20 to rotate and open, so that the opening angle of the valve disc reaches the 20° counterweight structure limit. When the valve plate 20 rotates and contacts the counterweight 41, the counter-torque formed by the counterweight 41 is greater than MG, so the valve disc is kept in this position to maintain the slightly open state.

[0070] Combination Figure 5 When the pipeline system has medium flowing through the check valve in the forward direction, based on the aforementioned initial slightly open state, at low flow rates, the medium flow velocity is low, and the flow of the medium is almost unaffected by the valve disc; as the medium flow rate and pressure inside the valve further increase, the valve disc opening angle gradually increases, and the rotational torque formed by the medium is in the same direction as MG. The combined force of the two forces is greater than the reverse torque formed by the counterweight 41, causing the valve plate 20 to push the counterweight 41 to rotate together. When the fluid flow rate reaches the rated value, the valve plate 20 can reach the fully open position.

[0071] Combination Figure 6 When the medium in the pipeline system flows in the reverse direction, the opening force of the medium on the valve plate 20 disappears. Under the gravity of the counterweight 41, the valve plate 20 quickly rotates in the reverse direction of closing. At the same time, the reverse-flowing medium acts on the outside of the valve plate 20, helping the valve plate 20 to rotate in the reverse direction of closing. The valve plate 20 closes quickly under the combined action of the inertial force of the counterweight 41 and the fluid dynamics.

[0072] When the valve plate 20 is open, the initial opening torque is provided by the gravity balance body 30 and the limit is provided by the counterweight mechanism 40. It does not need to overcome the preload of the return spring, so that the medium flow at a small opening does not affect the valve disc and maintains stable operation with a slight opening. When the flow is reversed, it is closed by the gravity of the counterweight mechanism 40, its own weight and the thrust of the reverse medium. This ensures the reliability of the reverse closing and eliminates the need for life-delay components such as springs. It not only has a long service life and high reliability, but also does not need to overcome additional resistance, thus avoiding the valve disc from experiencing slight opening chatter.

[0073] In summary, the micro-opening, low-flow-resistance swing check valve provided in this embodiment controls the opening and closing of the valve disc through a counterweight structure. It can maintain a stable micro-opening state initially without the need for a reset spring. The flow of the medium at low flow rates does not affect the valve disc, and it has low flow resistance characteristics when fully open, avoiding unnecessary system capacity loss and ensuring that the system flow meets requirements. While fully ensuring the valve's flow capacity, it avoids insufficient opening or valve disc flutter, thereby improving the stability and reliability of the fluid pipeline system. This is of great significance for ensuring the high-reliability operation of fluid systems in nuclear power plants and other similar facilities.

[0074] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A micro-opening, low-flow-resistance swing check valve, characterized in that, include: The valve body (10) is provided with an inlet channel (11), a valve chamber (12) and an outlet channel (13), wherein the valve chamber (12) is configured to connect the inlet channel (11) and the outlet channel (13); The valve assembly, installed in the valve cavity (12), includes a valve plate (20), a gravity balance body (30), and a counterweight mechanism (40). Wherein, one end of the valve plate (20) is rotatably connected to the side wall of the valve cavity (12) and connected to the gravity balance body (30); The gravity balance body (30) is eccentrically positioned with respect to the rotation axis of the valve plate (20), and can drive the valve plate (20) to rotate in a direction away from the inlet channel (11); The counterweight mechanism (40) is installed on the rotation path of the valve plate (20), can rotate along a preset axis, and is limited to the side of the valve plate (20) away from the inlet channel (11); In the installed state, the counterweight mechanism (40) can limit the opening angle of the valve plate (20) so that the opening angle of the valve plate (20) is maintained at a set value.

2. The micro-opening low-flow-resistance swing check valve according to claim 1, characterized in that, It also includes a valve cover (50), which seals over the upper end of the valve cavity (12).

3. The micro-opening low-flow-resistance swing check valve according to claim 2, characterized in that, The valve cover (50) is connected to the valve body (10) by mounting bolts (51).

4. The micro-opening low-flow-resistance swing check valve according to claim 2, characterized in that, A sealing ring gasket (52) is provided between the valve cover (50) and the valve body (10), and the sealing ring gasket (52) is used to seal the gap between the valve cover (50) and the valve body (10).

5. The micro-opening low-flow-resistance swing check valve according to claim 2, characterized in that, The valve body (10) has a sealing lip weld (14) on the side facing the valve cover (50).

6. The micro-opening low-flow-resistance swing check valve according to claim 1, characterized in that, The outlet channel (13) has a tapered, gradually expanding structure.

7. The micro-opening low-flow-resistance swing check valve according to claim 1, characterized in that, It also includes a valve seat (60) which is sealed and inserted into the end of the inlet channel (11).

8. The micro-opening low-flow-resistance swing check valve according to claim 7, characterized in that, The valve seat (60) is welded and fixed to the valve body (10).

9. The micro-opening low-flow-resistance swing check valve according to claim 8, characterized in that, The side of the valve seat (60) facing the valve plate (20) is a ground surface.

10. The micro-opening low-flow-resistance swing check valve according to any one of claims 1 to 9, characterized in that, The valve disc assembly also includes a valve shaft (70), and the valve plate (20) is rotatably connected to the valve body (10) via the valve shaft (70).

11. The micro-opening low-flow-resistance swing check valve according to claim 10, characterized in that, The valve plate (20) assembly also includes a connecting rod (80), one end of which is rotatably connected to the valve shaft (70) and fixedly connected to the gravity balance body (30).

12. The micro-opening low-flow-resistance swing check valve according to claim 11, characterized in that, The valve shaft (70) is fitted with a bushing made of self-lubricating material and located between the valve shaft (70) and the connecting support rod (80).

13. The micro-opening low-flow-resistance swing check valve according to claim 11, characterized in that, A connecting shaft (21) is provided in the middle of the valve plate (20), and the connecting shaft (21) is connected to the connecting support rod (80) through a spherical self-centering structure (22).

14. The micro-opening low-flow-resistance swing check valve according to claim 10, characterized in that, A support platform (15) is provided on the side wall of the valve chamber (12). The counterweight mechanism (40) includes a counterweight (41), the handle of which is rotatably connected to the valve shaft (70), and the head of which is fixed on the support platform (15).

15. The micro-opening low-flow-resistance swing check valve according to claim 14, characterized in that, The counterweight (41) has a support shaft (42) on its hammer head. In the installed state, the support shaft (42) abuts against the support platform (15).

16. The micro-opening low-flow-resistance swing check valve according to any one of claims 1 to 9, characterized in that, The gravity balance body (30) is equipped with a balance adjustment component, which is made of high-density metal.

17. The micro-opening low-flow-resistance swing check valve according to claim 16, characterized in that, The balance adjustment component is made of tungsten alloy.

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