Check valve and acid discharge system for preventing acid gas and acid liquor from flowing reversely

Abstract

The utility model provides a check valve and an acid discharge system for preventing acid gas and acid liquor from reversely flowing, which comprise a valve core component and a hollow valve body, and the valve core component is arranged in the hollow valve body; the valve element assembly comprises an elastic piece and a blocking piece, the hollow valve body sequentially comprises a first limiting part, a movable part and a second limiting part, the blocking piece is installed at one end of the spring and limited in the movable part through the first limiting part, and the second limiting part is installed at the other end of the spring. And the elastic piece is limited in the movable part through the second limiting part. And the check valve ensures that the fluid can only flow in one direction, so that the reverse flow phenomenon is effectively prevented. Through the reasonable layout of the valve core assembly and the hollow valve body structure design, the installation and maintenance of the check valve become more flexible and convenient, the design allows rapid installation and replacement, and the maintenance time and cost are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to one -way valve field especially relates to a check valve and prevent acid gas and acid liquid backflow's acid discharging system. BACKGROUND

[0002] In the equipment handling chemical liquids, such as the equipment supplying acidic liquid, the cleaning equipment and the wet process equipment, etc., a "leak-proof tray" is usually equipped below these equipments. The main function of this tray is to temporarily collect the leaked liquid in the tray in the emergency situation of chemical liquid leakage, so as to effectively control the spread of the leaked liquid and reduce the possible damage and pollution. In this way, the leak-proof tray provides valuable time for handling the leakage accident to take further emergency measures.

[0003] The acid discharging pipeline equipped with the leak-proof tray should be kept unobstructed at all times to ensure that the acid discharging operation can be carried out quickly in the event of chemical liquid leakage, so as to timely control and reduce the impact of the leakage. However, this design has two main problems:

[0004] 1. A large amount of acidic gas may accumulate in the main acid discharging pipeline. In some cases, these acid gases flow back along the acid discharging pipeline and may enter the clean room, causing the air quality of the clean room to deteriorate, affecting the environmental control standards, and thus possibly causing damage to the equipment and materials in the room.

[0005] 2. When multiple wet process equipment discharges waste acid at the same time, the capacity and discharge speed of the main acid discharging pipeline are insufficient to cope with the sudden increase in the amount of waste acid, which may cause the accumulation of waste acid in the pipeline, and even the phenomenon of backflow. This not only reduces the efficiency of acid discharging, but also may trigger the leakage sensor, causing the machine to mistakenly identify a leakage accident and shut down, affecting the continuity and stability of the production process. SUMMARY

[0006] In order to solve all or part of the problems of the prior art, the utility model provides a check valve and an acid discharging system for preventing acid gas and acid liquid backflow. By installing the check valve of the utility model on the acid discharging pipeline of the leak-proof tray, the acid liquid is allowed to flow from the leak-proof tray to the main acid discharging pipeline, while any possible backflow of acid gas and acid liquid is prevented, thereby protecting the clean room environment and equipment safety.

[0007] To achieve the above purpose, the utility model provides the following technical scheme:

[0008] A check valve characterized by comprising a valve core assembly and a hollow valve body, the valve core assembly is installed in the hollow valve body; the valve core assembly comprises a resilient member and a blocking member, the hollow valve body comprises a first limiting portion, a movable portion and a second limiting portion in sequence, the blocking member is installed at one end of the resilient member, the blocking member is limited in the movable portion through the first limiting portion, and the resilient member is limited in the movable portion through the second limiting portion. The check valve ensures that the fluid can only flow in one direction, effectively preventing the reverse flow phenomenon. Through the reasonable layout of the valve core assembly and the hollow valve body structure design, the installation and maintenance of the check valve become more flexible and convenient, and the design allows quick installation and replacement, reducing the maintenance time and cost.

[0009] The hollow valve body further comprises an annular flange located on the side of the first limiting portion away from the movable portion. The annular flange provides an additional connection point, making the installation of the check valve more convenient, and allowing it to be quickly connected with other pipeline systems or components.

[0010] The movable portion comprises a valve core channel, the first limiting portion and the second limiting portion comprise a valve body channel, the inner diameter of the valve core channel is greater than the inner diameter of the valve body channel; a first step is formed at the connection between the first limiting portion and the movable portion for blocking the blocking member, and a second step is formed at the connection between the second limiting portion and the movable portion for installing the resilient member. The different inner diameters of the valve core channel and the valve body channel allow the valve core assembly to move flexibly in the movable portion while maintaining good cooperation with the valve body channel. The design of the first step provides a clear blocking point for the blocking member, and the second step provides an installation platform for the resilient member.

[0011] The blocking member is a blocking ball, the diameter of the blocking ball is greater than the inner diameter of the valve body channel, and the first step is an inclined blocking surface. The diameter of the blocking ball is greater than the inner diameter of the valve body channel, which ensures that when the check valve is closed, the blocking ball can tightly fit the inclined blocking surface of the first step to form a good seal.

[0012] The blocking ball is a hollow plastic ball, and the resilient member is a plastic spring with a spring coefficient less than 0.04 N / mm. Plastic material has good corrosion resistance, and hollow plastic ball is lighter in weight due to its hollow structure, making the check valve operation more convenient. The plastic spring with low spring coefficient provides moderate resilience, which helps the blocking ball move smoothly under the action of fluid pressure, reducing the water hammer effect or other pressure fluctuations that may be caused by rapid closing or opening.

[0013] The utility model discloses still provide a kind of acid discharging system for preventing acid gas and acid liquid backflow, comprising: the anti-leakage tray being arranged below main equipment, the anti-leakage tray bottom is connected with first acid discharging pipeline, the first acid discharging pipeline is connected to main acid discharging pipeline;One-way traffic structure is equipped on the first acid discharging pipeline, the one-way traffic structure allows the acid liquid in the anti-leakage tray to flow to the main acid discharging pipeline after passing the first acid discharging pipeline and is discharged, while preventing acid gas and / or acid liquid in the main acid discharging pipeline from backflowing to the anti-leakage tray by the first acid discharging pipeline.By being provided with one-way traffic structure on the first acid discharging pipeline, system ensures that acid liquid can only flow from the anti-leakage tray to the main acid discharging pipeline, effectively prevents the backflow of acid gas and acid liquid, reduces environmental pollution and safety risk.

[0014] The one-way traffic structure is a check valve, the check valve includes a valve core assembly and a hollow valve body, the valve core assembly is installed in the hollow valve body; The valve core assembly includes a resilient member and a blocking member, the hollow valve body includes a first limiting portion, a movable portion and a second limiting portion in sequence, the blocking member is installed at one end of the resilient member, the blocking member is limited in the movable portion through the first limiting portion, and the resilient member is limited in the movable portion through the second limiting portion. When fluid flows from the anti-leakage tray to the main acid discharging pipeline, fluid pressure directly acts on the blocking member of the check valve, and the elastic force generated by the pre-compression of the resilient member is overcome to a certain extent. Under the action of fluid pressure, the blocking member moves downward, thereby opening the passage of the hollow valve body and allowing fluid to pass. When fluid flow stops or reverses, the resilience of the resilient member pushes the blocking member towards the first limiting portion, and the blocking member returns to its initial position under the action of the elastic force of the resilient member, thereby closing the passage of the hollow valve body and preventing acid gas and acid liquid from backflowing to the anti-leakage tray.

[0015] The hollow valve body further includes an annular flange, the annular flange is located on the side of the first limiting portion away from the movable portion; The first acid discharging pipeline is provided with a groove for mounting the annular flange at the connection with the anti-leakage tray, and the hollow valve body is installed in the first acid discharging pipeline in interference fit. The design of the groove enables the annular flange to be conveniently connected with the anti-leakage tray, increases the connection reliability of the check valve and the pipeline system, and reduces the failure caused by unstable connection.

[0016] The one-way traffic structure is a one-way valve made of plastic material, which is installed on the first acid discharging pipeline through threaded or flange connection. Through threaded or flange connection, the plastic one-way valve can be conveniently installed in the pipeline system.

[0017] The main device is a wet process device, connected with a second acid discharge pipeline connected to the main acid discharge pipeline; a leakage sensor is installed in the anti-leakage tray near the first acid discharge pipeline.

[0018] The utility model has at least the following beneficial effects:

[0019] 1) By installing the check valve on the acid discharge pipeline, the utility model effectively prevents the backflow of acid gas and acid liquid, thereby protecting the clean room environment and equipment safety. This one-way flow design ensures that the acid liquid can only flow from the anti-leakage tray to the main acid discharge pipeline, avoiding corrosion and pollution problems that may be caused by backflow, and improving the safety of the working environment and the service life of the equipment.

[0020] 2) The check valve has a precise valve core assembly and a hollow valve body structure, which not only ensures the one-way flow of fluid, but also provides an additional connection point through the design of the annular flange, making the installation of the check valve more convenient and allowing it to be quickly connected to other pipeline systems or components. This design simplifies the installation process, improves the reliability of the system, and makes maintenance more convenient.

[0021] 3) The utility model selects plastic material as the main constituent material of the check valve, and the corrosion resistance of plastic ensures the stability of the check valve in the acid liquid environment. The use of hollow plastic balls and low-elasticity coefficient plastic springs not only reduces the weight of the check valve, improving the portability of the operation, but also reduces the water hammer effect or other pressure fluctuations that may occur due to rapid closing or opening through moderate spring force, thereby improving the stability of the system and the smoothness of the operation. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the utility model, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings described below are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor.

[0023] Figure 1 It is an internal structure diagram of the check valve in the embodiment 1 of the utility model.

[0024] Figure 2 It is a structure diagram of the acid discharge system for preventing backflow of acid gas and acid liquid in the embodiment 2 of the utility model.

[0025] Figure 3 It is an internal structure diagram of the check valve in the embodiment 2 of the utility model.

[0026] Reference signs: 1 - one-way traffic structure; 11 - elastic member; 12 - blocking member; 13 - first limiting portion; 14 - movable portion; 15 - second limiting portion; 16 - annular flange; 17 - first step; 18 - second step; 2 - main device; 3 - leak-proof tray; 4 - leakage sensor; 5 - first acid discharge pipeline; 6 - second acid discharge pipeline; 7 - main acid discharge pipeline. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0028] The implementation of the present application will be described in detail below in combination with specific embodiments.

[0029] Embodiment 1

[0030] In the embodiments of the present application, in combination with reference Figure 1 As shown in the figure, a check valve is provided, which is composed of a valve core assembly and a hollow valve body. The valve core assembly is installed in the hollow valve body.

[0031] The hollow valve body is divided into three main parts: a first limiting portion 13, a movable portion 14 and a second limiting portion 15. The movable portion 14 is located between the first limiting portion 13 and the second limiting portion 15, and constitutes the area where the valve core assembly mainly moves. The first limiting portion 13 is located at one end of the movable portion 14, which provides one end limiting for the valve core assembly. The second limiting portion 15 is located at the other end of the movable portion 14, which provides the other end limiting. The two end limiting portions together ensure that the valve core assembly does not exceed the predetermined range of movement. The movable portion 14 includes a valve core passage, which allows the valve core assembly to move up and down in the passage to control the flow direction of the fluid. The first limiting portion 13 and the second limiting portion 15 include a valve body passage, and the inner diameter of the valve core passage is designed to be larger than the inner diameter of the valve body passage, so as to ensure that the valve core assembly can move freely in the movable portion 14, while being properly supported and limited by the first limiting portion 13 and the second limiting portion 15. The hollow valve body further includes an annular flange located on the side of the first limiting portion 13 away from the movable portion 14, which is used for the installation of the check valve or the connection with other system components.

[0032] The valve core assembly consists of an elastic element 11 and a blocking element 12. The blocking element 12 is installed at one end of the elastic element 11, so that when the elastic element 11 is compressed or rebounds, the blocking element 12 will move accordingly, thereby controlling the opening and closing state of the check valve. The first limiting part 13 in the hollow valve body defines the range of the movable part 14. The first step 17 formed at the connection between the first limiting part 13 and the movable part 14 provides a stop point for the blocking element 12, preventing the blocking element 12 from moving excessively under fluid pressure. The elastic element 11 is restricted within the movable part 14 by the second limiting part 15. The second step 18 formed at the connection between the second limiting part 15 and the movable part 14 provides a stable mounting base for the elastic element 11. The second step 18 ensures the correct position of the elastic element 11 in the valve body, allowing the elastic element 11 to exert its elastic function within the defined space, while preventing the elastic element 11 from interfering with other components of the valve body. In the initial state, the elastic element 11 is designed to be in a pre-compressed state. Its rebound force acts on the blocking element 12, lifting the blocking element 12 to the first step 17 position in the hollow valve body, meaning the check valve is in the closed state. In this embodiment, the blocking element 12 is in the form of a blocking ball, with a diameter slightly larger than the inner diameter of the valve body channel. The first step 17 is an inclined blocking surface, ensuring a tight fit between the blocking ball and the first step 17 in the closed state, which can prevent fluid backflow as much as possible. Specifically, the blocking ball is designed as a hollow plastic ball. This lightweight material is easily lifted by the elastic element 11, and the corrosion resistance of plastic makes it suitable for use in chemically harsh environments. The elastic element 11 is a plastic spring with a low elastic coefficient. This low elastic coefficient plastic spring can provide an appropriate amount of return force to the blocking ball, and at the same time, it can quickly close when the fluid flows in the opposite direction to prevent backflow.

[0033] When the fluid flows in the forward direction, the fluid pressure acts on the blocking ball, overcoming the pre-compression force of the plastic spring, pushing the blocking ball away and opening the check valve. When the fluid stops flowing or flows in the reverse direction, the force of the plastic spring pushes the blocking ball back to the first step 17, closing the check valve and preventing backflow. In other embodiments, the shape of the blocking element 12 can be customized according to its functional requirements, such as spherical, conical, cylindrical, or butterfly shapes, to adapt to different fluid control strategies and valve body structures. The design of the first step 17 closely matches the shape of the blocking element 12, ensuring that the blocking element 12 can be stably positioned on the step when the check valve is closed, forming an effective seal.

[0034] Example 2

[0035] This utility model also provides an acid drainage system to prevent the backflow of acid gas and acid liquid, in conjunction with reference. Figure 2 , Figure 3As shown, the system is designed for equipment that uses chemical liquids, such as acid equipment, cleaning equipment, wet process equipment, etc., to prevent acid gas and acid liquid backflow, ensuring safe operation and environmental protection. The system includes a leak-proof tray 3 set below the main equipment 2 to collect any leaks that may occur, reducing the impact on the surrounding environment. The bottom of the leak-proof tray 3 is connected to a first acid drainage line 5, which is responsible for transporting the acid liquid collected in the leak-proof tray 3 to the main acid drainage line 7. In this embodiment, the main equipment 2 is a wet process equipment connected to a second acid drainage line 6 responsible for collecting the acid liquid generated by the equipment, and the second acid drainage line 6 transports the acid liquid generated by the wet process equipment to the main acid drainage line 7. The main acid drainage line 7 serves as a centralized channel responsible for collecting and transporting all acid liquids generated by the main equipment 2 and the leak-proof tray 3. Through the main acid drainage line 7, all collected acid liquids are uniformly transported to subsequent processing facilities.

[0036] In the leak-proof tray 3, a leak sensor 4 is also installed, which is mainly used to monitor and detect possible chemical liquid leaks. The leak sensor 4 is generally arranged at the inlet of the acid drainage line, and this location is chosen to ensure that the sensor can quickly sense the leaked material when a leak occurs, thereby achieving early warning. Once the leak sensor 4 detects a leak, it will send an alarm and trigger a safety mechanism, causing the main equipment 2 to automatically stop running (shutdown). This automatic shutdown is a preventive measure to prevent further damage to the equipment by the leaked material and to avoid potential risks to the environment and personnel safety. In this way, the leak sensor 4 provides an additional layer of safety for the wet process equipment.

[0037] To prevent the acid gas generated by the acid liquid in the main acid discharge pipeline 7 from entering the clean room along the first acid discharge pipeline 5 and causing pollution, and to prevent the acid liquid in the main acid discharge pipeline 7 from flowing back to the leak-proof tray 3 when multiple devices are simultaneously performing acid discharge operations, triggering the leak sensor 4 and causing the device to shut down. The utility model is provided with a one-way passage structure 1 on the first acid discharge pipeline 5, which only allows fluid to flow in one direction, i.e. from the leak-proof tray 3 to the main acid discharge pipeline 7. This structure effectively prevents the acid gas and / or acid liquid in the main acid discharge pipeline 7 from flowing back to the leak-proof tray 3, avoiding possible environmental pollution and safety risks. In normal operation, when the leak-proof tray 3 collects acid liquid, the one-way passage structure 1 opens, allowing the acid liquid to flow from the first acid discharge pipeline 5 to the main acid discharge pipeline 7. When the fluid pressure decreases, the structure closes, preventing backflow. The one-way passage structure 1 can be designed in various ways, such as a spring-loaded valve, a gravity check valve, or a hydraulic check valve, to achieve reliable one-way control. Considering the corrosive nature of the acid liquid, the material selection of the one-way passage structure 1 must be able to resist chemical corrosion, such as engineering plastics, to ensure long-term stable operation. Due to the height difference between the main acid discharge pipeline 7 and the main device 2, this design creates a pressure gradient, making it difficult for the acid liquid to flow back to the main device 2, thus reducing the likelihood of backflow. This natural pressure difference provides a certain degree of backflow protection for the system, reducing the need for a one-way passage structure 1. Although the second acid discharge pipeline 6 is not equipped with a one-way passage structure 1 in the current embodiment, the system design still retains flexibility, allowing adjustments to the second acid discharge pipeline 6 based on actual operating conditions and needs, including the installation of a one-way passage structure 1 if necessary.

[0038] In the present embodiment, the one-way passage structure 1 adopts the check valve design described in embodiment 1, which is not only easy to install, but is particularly suitable for existing pipeline systems, allowing for convenient late installation without the need for large-scale modification or replacement of existing systems. The design of the check valve is based on the detailed description above, specifically including a valve core assembly and a hollow valve body, with the valve core assembly installed in the hollow valve body. The valve core assembly includes a resilient member 11 and a blocking member 12, and the hollow valve body includes a first limiting portion 13, a movable portion 14, and a second limiting portion 15 in sequence. The blocking member 12 is installed at one end of the resilient member 11, the blocking member 12 is limited in the movable portion 14 through the first limiting portion 13, and the resilient member 11 is limited in the movable portion 14 through the second limiting portion 15. The hollow valve body further includes an annular flange, which is located on the side of the first limiting portion 13 away from the movable portion 14. The connection between the first acid discharge pipeline 5 and the leak-proof tray 3 is provided with a groove for installing the annular flange. The hollow valve body is installed in the first acid discharge pipeline 5 through interference fit, which provides a relatively firm connection.

[0039] The elastic member 11 of the check valve is selected from a plastic spring with low elastic coefficient, which allows the spring to provide appropriate return force when the fluid flows reversely, and ensures that the check valve can be closed quickly when the weight of the fluid exceeds the spring force, thereby preventing reverse flow.

[0040]

[0041] wherein w is the weight of the blocking member 12, d is the diameter of the first limiting portion 13, h is the height thereof, p is the specific gravity of the liquid, L1 is the free length of the elastic member 11, and L2 is the length of the elastic member 11 after being compressed in the check valve. In order to ensure that the check valve can work effectively when the weight of the fluid exceeds the spring force, the elastic coefficient of the selected elastic member 11 must be less than the calculated value. In this way, when the weight of the leakage liquid flowing from the leak-proof tray 3 plus the weight of the blocking member 12 is greater than the elastic force exerted by the elastic member 11, the blocking member 12 will be pressed down, allowing the leakage liquid to be discharged downward, thereby achieving effective leakage discharge and reverse flow protection. In the embodiment, the free length L1 of the elastic member 11 is set to 30 mm, the estimated weight w of the blocking member 12 is 1 g, and the estimated specific gravity p of the liquid is 1 g / cm 3 . According to the formula, wherein d is the diameter of the first limiting portion 13, which is set to 1.6 cm, h is 10 mm, and L2 is the length of the spring after being compressed, which is set to 25 mm. Substituting the numerical values into the formula, it is calculated that k = 4.22 g / mm = 0.04 N / mm (Note: 1 g = 1 / 1000 * 9.8 = 0.0098 N). This calculation result shows that the elastic coefficient of the elastic member 11 is controlled at a relatively low value, so as to ensure that the blocking member 12 can move down smoothly when the weight of the fluid exceeds the spring force, allowing the leakage liquid to be discharged downward, thereby achieving effective leakage discharge and reverse flow protection. This design not only improves the safety of the system, but also ensures the reliability and flexibility of the operation of the check valve by precisely controlling the elastic coefficient of the elastic member 11.

[0042] Since the design of the check valve allows for later installation, the existing pipeline system can improve its performance and safety by installing the check valve without undergoing large-scale modification. In other specific embodiments of the acid discharge system, in order to meet different installation requirements and system configurations, the one-way passage structure 1 can also be a plastic one-way valve. The plastic one-way valve can be installed as part of the design in the early stage of pipeline system construction, or installed later to adapt to different installation requirements and system configurations. It can be installed on the first acid discharge pipeline 5 through standard threaded connection or flange connection, facilitating quick installation and maintenance. The plastic one-way valve has good corrosion resistance and is suitable for use in corrosive media such as acid liquid, reducing maintenance costs and replacement frequency.

[0043] In the prior art, by modifying the acid drainage pipe of the leak-proof tray 3 from a straight-line design to a P-trap structure with an S-shaped bend, the backflow of acid gas into the cleanroom environment can be effectively prevented. This design utilizes the water seal principle, blocking the flow of acid gas by creating a water barrier in the pipe. However, this modification also presents some challenges and issues: the construction process becomes more complex, as the installation of the S-shaped bend is more intricate than a straight pipe, requiring precise positioning and connection to ensure the sealing and functionality of the P-trap. The P-trap occupies a larger space, which is particularly problematic in high-value floor areas where the space under the floor is limited, potentially affecting the installation and maintenance of other equipment. Regular injection of clean water into the P-trap is required to maintain the effectiveness of the water seal. If not replaced regularly, the water in the P-trap can gradually become acidic due to the absorption of acid gas, eventually losing its ability to block acid gas and causing it to be released again. Although the P-trap can prevent the backflow of acid gas, it does not completely solve the problem of acid liquid backflow. When the waste acid discharge exceeds the processing capacity of the secondary acid drainage pipe, the P-trap still cannot prevent the waste acid from flowing back from the acid drainage pipe, which can trigger the leak sensor 4 and cause the machine to shut down.

[0044] The acid drainage system of the present utility model improves the operation safety and system reliability significantly through the carefully designed one-way passage structure 1. The check valve is made of plastic material, which not only reduces the cost, but also enhances the corrosion resistance, suitable for harsh chemical environment. The combination of the innovative elastic member 11 and the blocking member 12 ensures the precise control of the opening and closing of the check valve, and the integration of the leak sensor 4 provides protection for early leakage detection. Once leakage is detected, the safety mechanism can be triggered immediately to automatically stop the equipment operation, avoiding potential safety and environmental risks. In addition, the late installation capability of the check valve and the convenient installation method through threaded or flanged connection enable the existing pipeline system to be upgraded quickly without large-scale modification, improving performance and safety. The acid drainage system of the present utility model provides a safe, reliable and economical solution for equipment using chemical liquids with its innovation, flexibility and cost-effectiveness.

[0045] It should be noted that for those skilled in the art, without departing from the principles of the present utility model, the present utility model can be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present utility model.

Claims

1. A check valve characterized by comprising: The valve core assembly is installed in the hollow valve body; the valve core assembly comprises an elastic member (11) and a blocking member (12), the hollow valve body comprises a first limiting portion (13), a movable portion (14) and a second limiting portion (15) in sequence, the blocking member (12) is installed at one end of the elastic member (11), the blocking member (12) is limited in the movable portion (14) through the first limiting portion (13), and the elastic member (11) is limited in the movable portion (14) through the second limiting portion (15); the elastic member (11) and the blocking member (12) are both made of plastic material, and the elastic coefficient of the elastic member is less than 0.04 N / mm; the hollow valve body further comprises an annular flange (16), and the annular flange (16) is located on the side, away from the movable portion (14), of the first limiting portion (13).

2. The check valve of claim 1, wherein The movable portion (14) comprises a valve core channel, the first limiting portion (13) and the second limiting portion (15) comprise valve body channels, the inner diameter of the valve core channel is greater than the inner diameter of the valve body channel; a first step (17) is formed at the connection between the first limiting portion (13) and the movable portion (14) for blocking the blocking member (12), and a second step (18) is formed at the connection between the second limiting portion (15) and the movable portion (14) for installing the elastic member (11).

3. The check valve of claim 2, wherein The blocking member (12) is a blocking ball, the diameter of the blocking ball is greater than the inner diameter of the valve body channel, and the first step (17) is an inclined blocking surface.

4. The check valve of claim 3, wherein The blocking ball is a hollow plastic ball, and the elastic member (11) is a plastic spring with an elastic coefficient less than 0.04 N / mm.

5. An acid discharge system for preventing backflow of acid gas and acid liquid, characterized by, It comprises: A leakage-proof tray (3) arranged below a main device (2), a first acid discharging pipeline (5) connected to the bottom of the leakage-proof tray (3), and the first acid discharging pipeline (5) connected to a main acid discharging pipeline (7); A one-way passage structure (1) arranged on the first acid discharging pipeline (5), which allows the acid liquid in the leakage-proof tray (3) to flow to the main acid discharging pipeline (7) through the first acid discharging pipeline (5) and then be discharged, and prevents the acid gas and / or acid liquid in the main acid discharging pipeline (7) from flowing back to the leakage-proof tray (3) through the first acid discharging pipeline (5).

6. The acid drainage system of claim 5, wherein, The one-way passage structure (1) is a check valve, the valve core assembly is installed in the hollow valve body; the valve core assembly comprises an elastic member (11) and a blocking member (12), the hollow valve body comprises a first limiting portion (13), a movable portion (14) and a second limiting portion (15) in sequence, the blocking member (12) is installed at one end of the elastic member (11), the blocking member (12) is limited in the movable portion (14) through the first limiting portion (13), and the elastic member (11) is limited in the movable portion (14) through the second limiting portion (15).

7. The acid drainage system of claim 6, wherein, The hollow valve body further comprises an annular flange (16) located on the side of the first limiting part (13) away from the movable part (14); a groove for mounting the annular flange (16) is arranged at the connection between the first acid discharge pipeline (5) and the anti-leakage tray (3), and the hollow valve body is mounted in the first acid discharge pipeline (5) in an interference fit.

8. The acid drainage system of claim 5, wherein, The one-way passing structure (1) is a one-way valve made of plastic, which is installed on the first acid discharge pipeline (5) in a threaded or flange connection mode.

9. The acid drainage system of claim 5, wherein, The main equipment (2) is a wet process equipment, which is connected with a second acid discharge pipeline (6) connected to a main acid discharge pipeline (7); a leakage sensor (4) is installed in the anti-leakage tray (3) near the first acid discharge pipeline (5).

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