Water seal check valve

Abstract

The utility model relates to non return valve technical field, concretely is water seal check valve, including valve body, the lower part of valve body outer wall is equipped with L shape air inlet pipe, the top of valve body is equipped with air outlet pipe, the position of valve body in and close bottom is equipped with electric heating rod, the front and back sides of valve body inner wall are rotatably connected with water seal subassembly, and water seal subassembly includes rotating lever, the outer wall of rotating lever is equipped with two and is symmetrically set up the connecting rod of front and back, the top end of two connecting rods is connected with the rotary cover in common, the inner wall of rotating lever passes through the valve body and is equipped with U shape connecting block, and the front side of valve body is equipped with U shape fixed plate, the inner side of U shape fixed plate is rotatably connected with first hydraulic cylinder, and the movable rod of first hydraulic cylinder is rotatably connected with U shape connecting block. The water seal check valve, through set up electric heating rod, effectively solved the problem that water seal failure of low temperature environment under the liquid water in the valve icing, ensure the reliable operation of the valve under cold working condition, improve the environmental adaptability of system.

Description

Technical Field

[0001] This utility model relates to the field of check valve technology, specifically a water-sealed check valve. Background Technology

[0002] A water-sealed check valve is a valve used to prevent gas backflow. Its working principle is based on the water seal effect. A water seal chamber is set inside the valve, with the output end of the submerged pipe above the water surface. When the rotary cover rotates to be directly above the output end of the submerged pipe, the open end of the rotary cover is below the water surface, and the output end of the submerged pipe is inside the rotary cover, thus creating a water seal. The advantages of a water-sealed check valve are its relatively simple structure and its ability to adapt well to various gas conditions.

[0003] Patent CN218208000U discloses a water-sealed check valve, including a valve body. The valve body is hollow and cylindrical. An overflow pipe is installed on one circular side of the valve body. A connecting pipe is provided on the overflow pipe, connecting the inside of the overflow pipe to the inside of the valve body. A partition plate is also fixedly connected inside the overflow pipe, dividing the overflow pipe into upper and lower parts. The upper part of the overflow pipe is connected to an inlet valve, and the lower part of the overflow pipe is connected to a drain valve. The partition plate is located below the connecting pipe, and a drain pipe connecting the upper and lower parts of the overflow pipe is fixedly connected to the partition plate. The top of the drain pipe is higher than the top of the connecting pipe, and the bottom of the drain pipe is lower than the partition plate. The overflow pipe structure of this utility model can automatically maintain the water level by maintaining a dynamic balance of water level.

[0004] The existing water-sealed check valves described above can automatically maintain water level by maintaining dynamic water level balance, but they have significant shortcomings in low-temperature environments. When the ambient temperature drops, the water inside the valve may freeze, causing the water seal to fail and preventing the rotary cover from rotating properly. This situation not only affects the normal operation of the valve but may also pose a serious threat to the entire fluid transport system. Therefore, to solve this problem, we propose a water-sealed check valve, which aims to ensure reliability and effectiveness in low-temperature environments, thereby improving the applicability and safety of the water-sealed check valve. Utility Model Content

[0005] The purpose of this invention is to provide a water-sealed check valve to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A water-sealed check valve includes a valve body, which serves as the core housing, providing the water seal cavity and the basic structure for installing other components. Figure 1 , Figure 4 and Figure 6As shown, an L-shaped air inlet pipe is provided through the lower middle part of the outer wall of the valve body. The L-shaped air inlet pipe is used to guide gas into the valve body. Its output end is located above the liquid surface in the water seal chamber. An air outlet pipe is provided through the top of the valve body. The air outlet pipe is used to discharge gas. Its bottom end cooperates with the rotary cover to achieve a seal. An electric heating rod is provided in the valve body and near the bottom. The electric heating rod is connected to an external power supply and a thermostat to keep the water in the valve body at a constant temperature. The temperature is controllable, as long as the water does not freeze.

[0008] A water seal assembly is rotatably connected between the front and rear sides of the inner wall of the valve body. The water seal assembly switches the position of the rotary cover by rotation to achieve water seal or release the seal. The water seal assembly includes a rotating rod, which serves as a rotation axis and transmits hydraulic driving force to the connecting rod and the rotary cover. The outer wall of the rotating rod is provided with two connecting rods arranged symmetrically front and rear. The connecting rods are used to connect the rotating rod and the rotary cover and transmit rotational motion. The top ends of the two connecting rods are connected to the rotary cover. The rotary cover is immersed in the water surface through the opening to form a water seal, or is removed from the water surface to release the seal. The front end of the rotating rod passes through the inner wall of the valve body and is provided with a U-shaped connecting block. The connection between the rotating rod and the valve body is a sealed rotational connection. The U-shaped connecting block is used to connect the movable rod of the first hydraulic cylinder to convert linear motion into rotational motion.

[0009] The valve body has a U-shaped fixing plate on the front side, which provides a fixed fulcrum for the first hydraulic cylinder to ensure the stability of the hydraulic drive. The first hydraulic cylinder is rotatably connected to the inner side of the U-shaped fixing plate and connected to the external hydraulic drive system. The first hydraulic cylinder drives the rotating rod to rotate through hydraulic drive, controlling the switching of the water seal state. The movable rod of the first hydraulic cylinder is rotatably connected to the U-shaped connecting block. The movable rod of the first hydraulic cylinder pushes the U-shaped connecting block to rotate, causing the U-shaped connecting block to drive the rotating rod to rotate, thereby causing the rotating rod to drive the two connecting rods to rotate, and then causing the two connecting rods to drive the rotary cover to rotate. When the rotary cover rotates to the top, the opening of the rotary cover faces downward and is submerged below the water surface, producing a water seal effect.

[0010] Preferred, such as Figure 5 As shown, an inner tube is provided between the front and rear sides of the inner wall of the L-shaped air intake pipe, and the rotating rod passes through the inner tube. The inner tube provides a passage for the rotating rod to ensure the sealing between the rotating rod and the L-shaped air intake pipe.

[0011] Preferred, such as Figure 6 As shown, the bottom ends of both connecting rods are equipped with counterweights, which are used to balance the weight of the rotary cover and keep it in a stable position when there is no external force.

[0012] The outer wall of the rotary cover is provided with a first sealing gasket, which is used to fit against the bottom end of the air outlet pipe to prevent gas from leaking from the air outlet pipe. The inner wall of the rotary cover is provided with a second sealing gasket, which is used to fit against the output end of the L-shaped air inlet pipe to block the gas backflow path and achieve a double sealing effect in conjunction with the water seal.

[0013] The bottom end of the air outlet pipe is located directly above the output end of the L-shaped air inlet pipe. When the rotary cover is in a water-sealed state, the convex surface of the first sealing gasket is in contact with the bottom end of the air outlet pipe, and the concave surface of the second sealing gasket is in contact with the output end of the L-shaped air inlet pipe.

[0014] Preferred, such as Figure 4 As shown, the valve body is equipped with a guide, which is used to reduce water vapor entering the vent pipe when the water seal is released, thereby improving system reliability. The guide includes two second hydraulic cylinders arranged symmetrically on the left and right, which are connected to an external hydraulic drive system. The second hydraulic cylinders control the lifting and lowering of the rectangular tube through hydraulic drive. The movable rod of the second hydraulic cylinder passes through the top of the valve body and is fixedly connected to a moving plate. The moving plate connects the second hydraulic cylinder and the rectangular tube, transmitting vertical displacement. A rectangular tube is provided between the two moving plates. The rectangular tube is sleeved on the outside of the connection between the vent pipe and the L-shaped inlet pipe, blocking the upward path of water vapor.

[0015] The rectangular tube is sleeved on the outside of the rectangular tube. When the rotating cover is released from the water seal state, the rectangular tube is sleeved on the outside of the connection between the air outlet pipe and the L-shaped air inlet pipe. The movable rod of the second hydraulic cylinder extends and drives the rectangular tube to move down, so that the rectangular tube is sleeved on the outside of the connection between the air outlet pipe and the L-shaped air inlet pipe, effectively reducing the amount of water vapor entering the air outlet pipe.

[0016] Preferred, combined Figure 3 and Figure 4 As shown, a water inlet pipe is provided on the outer wall of the valve body near the top. The water inlet pipe is controlled by a solenoid valve to inject water and maintain the dynamic balance of the liquid level in the water seal cavity. A solenoid valve is provided on the water inlet pipe. A drain pipe with a valve is provided at the bottom of the valve body. The drain pipe is used to drain the water in the valve body, which is convenient for maintenance or emptying the water seal cavity.

[0017] The upper middle part of the inner wall of the valve body is equipped with a first water level sensor and a second water level sensor. The solenoid valve, the first water level sensor, and the second water level sensor are connected to an external power supply and a controller for operation. The first water level sensor is located below the second water level sensor. The first water level sensor detects a low water level and triggers a water replenishment operation. The second water level sensor detects a high water level and triggers a stop water injection operation. The controller controls the solenoid valve to ensure the stability of the water seal. When the rotary cover is in the water seal state, the bottom of the rotary cover is located below the first water level sensor to ensure that the bottom of the rotary cover is below the water surface. The second water level sensor is located below the output end of the L-shaped air inlet pipe to prevent water from entering the L-shaped air inlet pipe.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] 1. This water-sealed check valve, by setting up an electric heating rod linked with a temperature controller, effectively solves the problem of water seal failure caused by the freezing of liquid water inside the valve in low-temperature environments, ensuring reliable operation of the valve in cold conditions and improving the environmental adaptability of the system.

[0020] 2. This water seal check valve, through the coordinated control of the first and second water level sensors and the automatic water replenishment function of the solenoid valve, can monitor and dynamically adjust the liquid level in the water seal chamber in real time, avoiding errors caused by manual intervention and significantly improving the stability of the water seal effect.

[0021] 3. The water seal check valve adopts a double sealing design with an outer wall first sealing gasket and an inner wall second sealing gasket on the rotary cover. Together with the water seal, it forms a multi-layer sealing barrier. Even when there are air pressure fluctuations or backflow impacts, it can still effectively block the gas backflow path and avoid system abnormalities or safety hazards.

[0022] 4. The water-sealed check valve features a rectangular tube in its guide that controls the lifting and lowering of the valve. When the water seal is released, the tube covers the connection between the outlet and inlet pipes, reducing the amount of water vapor entering the outlet pipe, lowering the risk of internal condensation or corrosion, and extending the valve's service life. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0024] Figure 2 This is a schematic diagram of the overall cross-sectional structure of this utility model;

[0025] Figure 3 This utility model Figure 2 Enlarged structural diagram at point A;

[0026] Figure 4 This is a schematic diagram of the internal assembly structure of the valve body in this utility model;

[0027] Figure 5 This is a schematic diagram of the L-shaped air inlet and outlet pipe structure in this utility model;

[0028] Figure 6 This is a schematic diagram of the water seal component structure in this utility model;

[0029] In the diagram: 100, valve body; 110, U-shaped fixing plate; 120, drain pipe; 130, electric heating rod; 200, L-shaped air inlet pipe; 210, inner pipe; 300, air outlet pipe; 400, water seal assembly; 410, rotating rod; 420, connecting rod; 430, rotating cover; 440, counterweight; 450, first sealing gasket; 460, second sealing gasket; 470, U-shaped connecting block; 500, first hydraulic cylinder; 600, guide; 610, second hydraulic cylinder; 620, moving plate; 630, rectangular tube; 700, first water level sensor; 800, second water level sensor; 900, water inlet pipe. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are 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, and therefore should not be construed as a limitation of this utility model.

[0032] Please see Figures 1-6 This utility model provides a technical solution:

[0033] The water-sealed check valve includes a valve body 100. The valve body 100 serves as the core housing, providing the water seal cavity and the basic structure for installing other components. Figure 1 , Figure 4 and Figure 6 As shown, an L-shaped air inlet pipe 200 is provided through the lower middle part of the outer wall of the valve body 100. The L-shaped air inlet pipe 200 is used to guide gas into the interior of the valve body 100. Its output end is located above the liquid surface of the water seal chamber. An air outlet pipe 300 is provided through the top of the valve body 100. The air outlet pipe 300 is used to discharge gas. Its bottom end cooperates with the rotary cover 430 to achieve a seal. An electric heating rod 130 is provided inside the valve body 100 and near the bottom. The electric heating rod 130 is connected to an external power supply and a thermostat to keep the water inside the valve body 100 heated at a constant temperature. The temperature is controllable, as long as the water does not freeze.

[0034] A water seal assembly 400 is rotatably connected between the front and rear sides of the inner wall of the valve body 100. The water seal assembly 400 achieves water sealing or unsealing by rotating the position of the rotary cover 430. The water seal assembly 400 includes a rotating rod 410, which serves as a rotating shaft to transmit hydraulic driving force to the connecting rod 420 and the rotary cover 430. The outer wall of the rotating rod 410 is provided with two connecting rods 420 arranged symmetrically in front and behind. The connecting rods 420 are used to connect the rotating rod 410 and the rotary cover 430 to transmit rotational motion. The top ends of the two connecting rods 420 are connected to the rotary cover 430. The rotary cover 430 is immersed in the water surface through the opening to form a water seal, or is removed from the water surface to unseal. The front end of the rotating rod 410 passes through the inner wall of the valve body 100 and is provided with a U-shaped connecting block 470. The connection between the rotating rod 410 and the valve body 100 is a sealed rotating connection. The U-shaped connecting block 470 is used to connect the movable rod of the first hydraulic cylinder 500 to convert linear motion into rotational motion.

[0035] A U-shaped fixing plate 110 is provided on the front side of the valve body 100. The U-shaped fixing plate 110 provides a fixed fulcrum for the first hydraulic cylinder 500 to ensure the stability of the hydraulic drive. The first hydraulic cylinder 500 is rotatably connected to the inner side of the U-shaped fixing plate 110 and is connected to the external hydraulic drive system. The first hydraulic cylinder 500 drives the rotating rod 410 to rotate through hydraulic drive, controlling the switching of the water seal state. The movable rod of the first hydraulic cylinder 500 is rotatably connected to the U-shaped connecting block 470. The movable rod of the first hydraulic cylinder 500 pushes the U-shaped connecting block 470 to rotate, so that the U-shaped connecting block 470 drives the rotating rod 410 to rotate, so that the rotating rod 410 drives the two connecting rods 420 to rotate, and then the two connecting rods 420 drive the rotating cover 430 to rotate. When the rotating cover 430 rotates to the top, the opening of the rotating cover 430 faces downward and is submerged below the water surface, producing a water seal effect.

[0036] In this embodiment, as Figure 5 As shown, an inner tube 210 is provided between the front and rear sides of the inner wall of the L-shaped air intake pipe 200. The rotating rod 410 passes through the inner tube 210, which provides a passage for the rotating rod 410 to ensure the sealing between the rotating rod 410 and the L-shaped air intake pipe 200.

[0037] Specifically, such as Figure 6 As shown, the bottom ends of the two connecting rods 420 are equipped with counterweights 440. The counterweights 440 are used to balance the weight of the rotating cover 430 so that it can maintain a stable posture when there is no external force.

[0038] The outer wall of the rotary cover 430 is provided with a first sealing gasket 450, which is used to fit against the bottom end of the air outlet pipe 300 to prevent gas from leaking from the air outlet pipe 300. The inner wall of the rotary cover 430 is provided with a second sealing gasket 460, which is used to fit against the output end of the L-shaped air inlet pipe 200 to block the gas backflow path and achieve a double sealing effect in conjunction with the water seal.

[0039] The bottom end of the air outlet pipe 300 is located directly above the output end of the L-shaped air inlet pipe 200. When the rotary cover 430 is in a water-sealed state, the convex surface of the first sealing gasket 450 is in contact with the bottom end of the air outlet pipe 300, and the concave surface of the second sealing gasket 460 is in contact with the output end of the L-shaped air inlet pipe 200.

[0040] Furthermore, such as Figure 4 As shown, the valve body 100 is provided with a guide 600. The guide 600 is used to reduce water vapor entering the air outlet pipe 300 when the water seal is released, thereby improving the reliability of the system. The guide 600 includes two second hydraulic cylinders 610 arranged symmetrically on the left and right, which are connected to an external hydraulic drive system. The second hydraulic cylinders 610 control the lifting and lowering of the rectangular tube 630 through hydraulic drive. The movable rod of the second hydraulic cylinder 610 passes through the top of the valve body 100 and is fixedly connected to a movable plate 620. The movable plate 620 connects the second hydraulic cylinder 610 and the rectangular tube 630 to transmit vertical displacement. A rectangular tube 630 is provided between the two movable plates 620. The rectangular tube 630 is sleeved on the outside of the connection between the air outlet pipe 300 and the L-shaped air inlet pipe 200 to block the upward path of water vapor.

[0041] The rectangular tube 630 is sleeved on the outside of the rectangular tube 630. When the rotating cover 430 is released from the water seal state, the rectangular tube 630 is sleeved on the outside of the connection between the air outlet pipe 300 and the L-shaped air inlet pipe 200. The movable rod of the second hydraulic cylinder 610 extends and drives the rectangular tube 630 to move down, so that the rectangular tube 630 is sleeved on the outside of the connection between the air outlet pipe 300 and the L-shaped air inlet pipe 200, effectively reducing the amount of water vapor entering the air outlet pipe 300.

[0042] Furthermore, in combination Figure 3 and Figure 4 As shown, a water inlet pipe 900 is provided on the outer wall of the valve body 100 near the top. The water inlet pipe 900 is controlled by a solenoid valve to maintain the dynamic balance of the liquid level in the water seal cavity. A solenoid valve is provided on the water inlet pipe 900. A drain pipe 120 with a valve is provided at the bottom of the valve body 100. The drain pipe 120 is used to drain the water in the valve body 100, which is convenient for maintenance or emptying the water seal cavity.

[0043] A first water level sensor 700 and a second water level sensor 800 are provided in the upper middle part of the inner wall of the valve body 100. The solenoid valve, the first water level sensor 700 and the second water level sensor 800 are connected to an external power supply and a controller for operation. The first water level sensor 700 is located below the second water level sensor 800. The first water level sensor 700 detects a low water level and triggers water replenishment. The second water level sensor 800 detects a high water level and triggers a stop water injection. The controller controls the solenoid valve to ensure water seal stability. When the rotary cover 430 is in the water seal state, the bottom of the rotary cover 430 is located below the first water level sensor 700 to ensure that the bottom of the rotary cover 430 is below the water surface. The second water level sensor 800 is located below the output end of the L-shaped air inlet pipe 200 to prevent water from entering the L-shaped air inlet pipe 200.

[0044] It should be noted that the electric heating rod 130, the first hydraulic cylinder 500, the second hydraulic cylinder 610, the first water level sensor 700, the second water level sensor 800, the solenoid valve, the temperature controller, the controller, and the hydraulic drive system in this utility model are all general standard parts or parts known to those skilled in the art. Their structure and principle can be learned by those skilled in the art through technical manuals or conventional experimental methods. The specific connection means should refer to the working sequence of each electrical component in the above working principle to complete the electrical connection. The detailed connection means are well known in the art. The above mainly introduces the working principle and process, and the electrical control will not be described again.

[0045] In this embodiment, the water seal check valve is used by first connecting an external water source through the inlet pipe 900 and activating the solenoid valve to inject an appropriate amount of water into the valve body 100 until the first water level sensor 700 detects a low water level signal and triggers automatic water replenishment. After the second water level sensor 800 detects a high water level, the solenoid valve is closed to ensure that the liquid level in the water seal chamber covers the bottom of the rotary cover 430. When water sealing is required, the external hydraulic drive system activates the first hydraulic cylinder 500, pushing the U-shaped connecting block 470 to rotate the rotating rod 410, causing the connecting rod 420 to drive the rotary cover 430 to rotate until the opening faces downward and is immersed in water. At this time, the first sealing gasket 450 is in contact with the bottom end of the air outlet pipe 300, and the second sealing gasket 460 is in contact with the L-shaped air inlet pipe. The output end of pipe 200 is fitted together, forming a double seal and water seal effect, preventing gas from escaping from the L-shaped air inlet pipe 200. When the water seal needs to be released, the first hydraulic cylinder 500 drives the rotating cover 430 to rotate, causing the rotating cover 430 to rotate 90°. At the same time, the second hydraulic cylinder 610 pushes the moving plate 620 to move the rectangular pipe 630 down to cover the connection between the air outlet pipe 300 and the L-shaped air inlet pipe 200, reducing the amount of water vapor entering the air outlet pipe 300. In low-temperature environments, the electric heating rod 130 uses a thermostat to heat the water in the valve body 100 at a constant temperature to prevent freezing. During routine maintenance, the solenoid valve of the water inlet pipe 900 is closed and the valve of the drain pipe 120 is opened to drain the liquid. After cleaning the impurities in the water seal cavity, water is refilled to restore its use.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A water-sealed check valve, comprising a valve body (100), characterized in that: An L-shaped air inlet pipe (200) is provided through the lower middle part of the outer wall of the valve body (100), and an air outlet pipe (300) is provided through the top of the valve body (100). An electric heating rod (130) is provided inside the valve body (100) near the bottom. A water seal assembly (400) is rotatably connected between the front and rear sides of the inner wall of the valve body (100). The water seal assembly (400) includes a rotating rod (410). The outer wall of the rotating rod (410) has two symmetrically arranged front and rear sides. The connecting rod (420) has a rotating cover (430) connected to the top of the two connecting rods (420). The front end of the rotating rod (410) passes through the inner wall of the valve body (100) and is provided with a U-shaped connecting block (470). A U-shaped fixing plate (110) is provided on the front side of the valve body (100). A first hydraulic cylinder (500) is rotatably connected to the inner side of the U-shaped fixing plate (110). The movable rod of the first hydraulic cylinder (500) is rotatably connected to the U-shaped connecting block (470).

2. The water-sealed check valve according to claim 1, characterized in that: An inner tube (210) is provided between the front and rear sides of the inner wall of the L-shaped air intake pipe (200), and the rotating rod (410) passes through the inner tube (210).

3. The water-sealed check valve according to claim 1, characterized in that: The bottom ends of both connecting rods (420) are provided with counterweights (440).

4. The water-sealed check valve according to claim 1, characterized in that: The outer wall of the rotary cover (430) is provided with a first sealing gasket (450), and the inner wall of the rotary cover (430) is provided with a second sealing gasket (460).

5. The water-sealed check valve according to claim 4, characterized in that: The bottom end of the air outlet pipe (300) is located directly above the output end of the L-shaped air inlet pipe (200). When the rotary cover (430) is in a water-sealed state, the convex surface of the first sealing gasket (450) is in contact with the bottom end of the air outlet pipe (300), and the concave surface of the second sealing gasket (460) is in contact with the output end of the L-shaped air inlet pipe (200).

6. The water-sealed check valve according to claim 1, characterized in that: The valve body (100) is provided with a guide (600), the guide (600) includes two second hydraulic cylinders (610) arranged symmetrically on the left and right. The movable rod of the second hydraulic cylinder (610) passes through the top of the valve body (100) and is fixedly connected to a movable plate (620). A rectangular tube (630) is provided between the two movable plates (620).

7. The water-sealed check valve according to claim 6, characterized in that: The rectangular tube (630) is sleeved on the outside of the rectangular tube (630). When the rotating cover (430) is released from the water seal state, the rectangular tube (630) is sleeved on the outside of the connection between the air outlet pipe (300) and the L-shaped air inlet pipe (200).

8. The water-sealed check valve according to claim 1, characterized in that: The valve body (100) has an inlet pipe (900) on its outer wall and near the top. The inlet pipe (900) is equipped with a solenoid valve. The valve body (100) has a drain pipe (120) with a valve at its bottom.

9. The water-sealed check valve according to claim 1, characterized in that: The valve body (100) has a first water level sensor (700) and a second water level sensor (800) in the upper middle part of its inner wall. The first water level sensor (700) is located below the second water level sensor (800). When the rotary cover (430) is in a water-sealed state, the bottom of the rotary cover (430) is located below the first water level sensor (700), and the second water level sensor (800) is located below the output end of the L-shaped air inlet pipe (200).

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