A bellows shut-off valve for phosgene pipelines

Abstract

This invention belongs to the field of gate valve technology, and specifically relates to a bellows gate valve for phosgene pipelines. It includes a valve body, valve seat, valve cover assembly, hollow valve stem, and handwheel. The outer wall of the hollow valve stem has a lifting thread that mates with the valve cover assembly. A corrosion-resistant rubber valve core that mates with the valve seat is fixedly sleeved at the bottom of the hollow valve stem. The corrosion-resistant rubber valve core has an expansion cavity inside, which communicates with an opening at the bottom of the hollow valve stem. This invention enables the bellows gate valve for phosgene pipelines to not only have impact buffering, phosgene leakage prevention, real-time monitoring and accurate alarm for sealing failure, but also multiple sealing functions when the gate valve is closed. This effectively improves the sealing effect and reliability of the gate valve, significantly enhances its protective performance, extends its service life, effectively avoids safety accidents caused by large-scale phosgene leakage, and improves the safety and reliability of phosgene pipeline operation.

Description

Technical Field

[0001] This invention belongs to the field of gate valve technology, and in particular relates to a bellows gate valve for phosgene pipelines. Background Technology

[0002] Phosgene is a colorless or slightly yellow gas with a strong, pungent or suffocating odor. It is also an important organic intermediate, a highly reactive electrophilic reagent, and easily hydrolyzed. A bellows is a pipe used to transport liquids and gases, formed by a series of corrugations that allow the pipe to have greater elasticity under certain pressure. Phosgene-specific bellows stop valves are mainly used for cutting off the medium in phosgene pipeline systems. The pipeline on / off control is achieved through the opening and closing of the valve core and valve seat. For example, patent CN222458369U discloses a phosgene-specific bellows stop valve.

[0003] Currently, in actual use, phosgene-specific bellows gate valves are subject to continuous scouring and wear from the gas-liquid two-phase phosgene. This can easily lead to damage defects such as increased surface roughness and dimensional accuracy deviations on the valve core sealing surface, directly compromising the sealing performance between the valve core and the valve seat. Furthermore, traditional phosgene-specific bellows gate valves generally lack real-time monitoring and alarm functions for valve core sealing failure, resulting in highly concealed phosgene leakage caused by sealing failure, which seriously reduces the safety and reliability of valve operation.

[0004] In addition, when existing phosgene-specific bellows stop valves are in operation, the flow velocity of the gas-liquid two-phase medium in the pipeline will change suddenly due to the fluctuation of phosgene delivery pressure and the rapid opening and closing of the valve, which will lead to air hammer. Frequent air hammer impact pressure will damage the internal structure of the stop valve, significantly shorten the service life of the phosgene pipeline bellows stop valve, and seriously threaten the stable operation of the phosgene pipeline system.

[0005] To address this issue, we propose a bellows shut-off valve for phosgene pipelines. Summary of the Invention

[0006] The purpose of this invention is to address the above-mentioned problems by providing a bellows shut-off valve for phosgene pipelines.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a bellows stop valve for phosgene pipelines, comprising a valve body, a valve seat, a valve cover assembly, a hollow valve stem, and a handwheel. The outer wall of the hollow valve stem is provided with a lifting thread that mates with the valve cover assembly. A corrosion-resistant rubber valve core that mates with the valve seat is fixedly sleeved at the bottom end of the hollow valve stem. An expansion cavity is provided inside the corrosion-resistant rubber valve core, and the expansion cavity communicates with the opening at the bottom of the hollow valve stem.

[0008] An air supply mechanism is fixedly sleeved on the outer wall of the hollow valve stem;

[0009] A phosgene leak-proof mechanism is fixedly sleeved on the outer wall of the valve body;

[0010] The outer wall of the phosgene leak-proof mechanism is fixedly connected to an outer cover. The top of the outer cover is fixedly embedded with a first sealing bearing. The inner wall of the first sealing bearing is fixedly connected to a connecting hose. The top of the connecting hose is fixedly connected to a threaded cap for fixing a handwheel. The top of the hollow valve stem is provided with a connecting thread that matches the thread on the inner wall of the threaded cap. The bottom of the outer cover is fixedly connected to a normally closed solenoid valve. The bottom of the normally closed solenoid valve is fixedly connected to a branch pipe.

[0011] The outer wall of the outer cover is fixedly connected to a sealing failure alarm mechanism.

[0012] In the aforementioned bellows shut-off valve for phosgene pipelines, the gas supply mechanism includes a support ring fixedly sleeved to the outer wall of a hollow valve stem. A corrosion-resistant rubber sleeve is fixedly sleeved to the outer wall of the support ring. The bottom end of the corrosion-resistant rubber sleeve is fixedly sleeved to the outer wall of the hollow valve stem. The top outer wall of the corrosion-resistant rubber sleeve is slidably and sealingly connected to the top inner wall of the valve body. A beveled extrusion ring that mates with the corrosion-resistant rubber sleeve is fixedly connected to the top inner wall of the valve body. An air inlet hole is provided on the outer wall of the hollow valve stem located at the corrosion-resistant rubber sleeve.

[0013] In the aforementioned bellows shut-off valve for phosgene pipelines, the phosgene leak-proof mechanism includes a protective housing fixedly sleeved to the outer wall of the valve body. The top of the protective housing has a fixed slot, and a sealing gasket ring is sleeved on the slot wall. A top cover is fixedly connected to the top of the protective housing by bolts. A corrosion-resistant rubber sealing cover is fixedly connected to the inner wall of the top cover. A second sealing ring is fixedly sleeved on the stem wall of the hollow valve stem. The outer wall of the second sealing ring is fixedly connected to the inner wall of the top of the corrosion-resistant rubber sealing cover. The bottom end of the branch pipe passes through the inner wall of the bottom end of the protective housing and extends into the interior of the protective housing.

[0014] In the above-mentioned bellows shut-off valve for phosgene pipeline, the bottom of the protective shell is filled with an absorbent liquid layer, and a liquid guide block is fixedly connected to the inner wall of the protective shell. The bottom end of the liquid guide block has an opening that matches both ends of the valve body, and the bottom end of the liquid guide block is located in the absorbent liquid layer.

[0015] In the aforementioned bellows shut-off valve for phosgene pipelines, the sealing failure alarm mechanism includes a fixed housing fixedly connected to the outer wall of the outer casing. An audible and visual alarm is fixedly connected to the outer wall of the fixed housing. A controller is fixedly connected to the outer wall of the outer casing located at the fixed housing. Two through holes are opened on the outer wall of the outer casing located at the fixed housing, and a pressure sensor and a phosgene sensor are fixedly connected to the walls of the two through holes.

[0016] In the aforementioned bellows shut-off valve for phosgene pipelines, the side wall of the outer casing is provided with an installation through hole, and a one-way air inlet is fixedly connected to the wall of the installation through hole.

[0017] In the above-mentioned bellows stop valve for phosgene pipelines, a sealing ring is movably sleeved at the joint between the hollow valve stem and the threaded cap, and a gasket ring is fixedly connected to the bottom end of the threaded cap.

[0018] In the above-mentioned bellows stop valve for phosgene pipeline, a fixed flange that mates with the valve cover assembly is fixedly connected to the upper surface of the valve body, and connecting flanges are fixedly connected to both the inlet end and the outlet end of the valve body.

[0019] Compared with existing technologies, the advantages of a bellows shut-off valve for phosgene pipelines are:

[0020] 1. Through the design of the corrosion-resistant rubber valve core and air supply mechanism, when the shut-off valve is installed, a certain amount of air is first injected into the outer casing through the one-way air inlet. This ensures that there is enough air in the air supply mechanism for the opening and closing of the corrosion-resistant rubber valve core, and also slightly expands the expansion cavity of the corrosion-resistant rubber valve core, providing a certain buffering capacity in advance. The stable air pressure in the outer casing after air injection is set as the air pressure reference threshold for the seal failure alarm. During the operation of the shut-off valve, if the gas-liquid two-phase phosgene experiences air hammer due to pressure fluctuations or rapid valve opening and closing, the impact force of the air hammer is buffered and offset by the deformation of the corrosion-resistant rubber valve core and the corrosion-resistant rubber sleeve, thereby significantly reducing the damage of the air hammer impact force to the internal structure of the shut-off valve. At the same time, the expansion of the corrosion-resistant rubber sleeve makes it fit more tightly against the inner wall of the valve body top, improving the sealing performance of the valve body top. This mechanism gives the shut-off valve an impact buffering function, effectively improving the shut-off valve's protection capability, thereby extending the service life of the shut-off valve and ensuring the stable operation of the phosgene pipeline system.

[0021] 2. Through the valve seat, air supply mechanism, and corrosion-resistant rubber valve core, when the corrosion-resistant rubber valve core of the gate valve closes with the flow hole of the valve seat, the hollow valve stem pushes the corrosion-resistant rubber valve core downward, causing it to gradually approach and insert into the flow hole of the valve seat. At the same time, the hollow valve stem drives the corrosion-resistant rubber sleeve to squeeze the inclined extrusion ring. Due to the obstruction and restriction of the inclined extrusion ring, the corrosion-resistant rubber sleeve undergoes a large-scale extrusion deformation. After being squeezed, the air inside the corrosion-resistant rubber sleeve is injected into the expansion cavity through the air inlet and the internal channel of the hollow valve stem, causing the corrosion-resistant rubber valve core to expand rapidly. The expanded corrosion-resistant rubber valve core is in the shape of an "I" and tightly adheres to the top surface, bottom surface, and wall of the flow hole of the valve seat, achieving multiple seals for the flow hole of the valve seat and greatly improving the sealing effect and reliability.

[0022] 3. Through the phosgene leak-proof mechanism, if the valve cover assembly fails to seal at the connection between the fixed flange and the valve body, resulting in phosgene leakage, the leaking phosgene will be confined by the closed space formed by the protective shell and the corrosion-resistant rubber sealing cover, making it difficult for it to diffuse to the outside. Moreover, due to the strong water absorption characteristics of the liquid guide block, the bottom of the liquid guide block can be continuously kept moist by being immersed in the absorbent liquid layer. When the leaking phosgene comes into contact with the solution in the liquid guide block, it will be treated by reaction. For example, phosgene reacts with water to generate an acidic solution and carbon dioxide. The accumulation of carbon dioxide will push the corrosion-resistant rubber sealing cover to bulge outward, forming a visual leak warning signal to remind the production site personnel that a leak has occurred and emergency maintenance is required. This mechanism enables the gate valve to have a phosgene leak-proof function, greatly improving the protective performance of the gate valve.

[0023] 4. With the extended service life of the gate valve, the surface of the corrosion-resistant rubber valve core will be damaged due to the erosion and wear of the medium, leading to the failure of the gate valve to close and seal. At this time, the sealing failure alarm mechanism will activate the corresponding alarm process according to the location of the leak and remind maintenance personnel to repair the gate valve in time. This mechanism enables the gate valve to have real-time monitoring and accurate alarm function for sealing failure, which can effectively avoid safety accidents caused by large-scale phosgene leakage and significantly improve the safety and reliability of phosgene pipeline operation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a bellows shut-off valve for phosgene pipelines provided by the present invention;

[0025] Figure 2 This is a three-dimensional structural diagram of the valve body portion of a bellows shut-off valve for phosgene pipelines provided by the present invention;

[0026] Figure 3 This is a partial cross-sectional view of the bellows shut-off valve for phosgene pipelines provided by the present invention.

[0027] Figure 4 This is a schematic diagram of the hollow valve stem portion of a bellows stop valve for phosgene pipelines provided by the present invention.

[0028] Figure 5 This is a schematic diagram of the phosgene leak prevention mechanism in a bellows stop valve for phosgene pipelines provided by the present invention.

[0029] Figure 6 This is a schematic diagram of the sealing failure alarm mechanism in a bellows stop valve for phosgene pipelines provided by the present invention;

[0030] Figure 7 This is a three-dimensional structural diagram of the liquid guide block in a bellows stop valve for phosgene pipelines provided by the present invention.

[0031] In the diagram: 1. Valve body; 2. Valve seat; 3. Valve cover assembly; 4. Hollow valve stem; 5. Handwheel; 6. Corrosion-resistant rubber valve core; 7. Air supply mechanism; 71. Support ring; 72. Corrosion-resistant rubber sleeve; 73. Beveled extrusion ring; 74. Air inlet; 8. Phosgene leak prevention mechanism; 81. Protective housing; 82. Sealing gasket ring; 83. Top cover; 84. Corrosion-resistant rubber sealing cover; 85. Second sealing ring; 9. Seal failure alarm mechanism; 1. Fixed housing; 92. Audible and visual alarm; 93. Controller; 94. Pressure sensor; 95. Phosphorus sensor; 10. Expansion cavity; 11. Outer cover; 12. First sealed bearing; 13. Connecting hose; 14. Threaded cap; 15. Normally closed solenoid valve; 16. Branch pipe; 17. Absorbent liquid layer; 18. Liquid guide block; 19. One-way air inlet; 20. Sealing ring; 21. Gasket ring; 22. Fixed flange; 23. Connecting flange. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figures 1-7 As shown, a bellows shut-off valve for phosgene pipelines includes a valve body 1, a valve seat 2, a valve cover assembly 3, a hollow valve stem 4, and a handwheel 5. The outer wall of the hollow valve stem 4 has a lifting thread that mates with the valve cover assembly 3. A corrosion-resistant rubber valve core 6 that mates with the valve seat 2 is fixedly sleeved at the bottom end of the hollow valve stem 4. An expansion cavity 10 is formed inside the corrosion-resistant rubber valve core 6, and the expansion cavity 10 communicates with the opening at the bottom of the hollow valve stem 4. A gas supply mechanism 7 is fixedly sleeved on the outer wall of the hollow valve stem 4 for gas supply. Mechanism 7 includes a support ring 71 that is fixedly sleeved to the outer wall of the hollow valve stem 4. A corrosion-resistant rubber sleeve 72 is fixedly sleeved to the outer wall of the support ring 71. The bottom end of the corrosion-resistant rubber sleeve 72 is fixedly sleeved to the outer wall of the hollow valve stem 4. The top outer wall of the corrosion-resistant rubber sleeve 72 is slidably connected to the top inner wall of the valve body 1. A beveled extrusion ring 73 that cooperates with the corrosion-resistant rubber sleeve 72 is fixedly connected to the top inner wall of the valve body 1. An air inlet 74 is opened on the outer wall of the hollow valve stem 4 at the corrosion-resistant rubber sleeve 72.

[0034] A phosgene leak-proof mechanism 8 is fixedly sleeved on the outer wall of the valve body 1. The phosgene leak-proof mechanism 8 includes a protective shell 81 fixedly sleeved on the outer wall of the valve body 1. A fixed slot is opened at the top of the protective shell 81, and a sealing gasket ring 82 is sleeved on the groove wall of the fixed slot. A top cover 83 is fixedly connected to the top of the protective shell 81 by bolts. A corrosion-resistant rubber sealing cover 84 is fixedly connected to the inner wall of the top cover 83. A second sealing ring 85 is fixedly sleeved on the stem wall of the hollow valve stem 4. The outer wall of the second sealing ring 85 is fixedly connected to the inner wall of the top of the corrosion-resistant rubber sealing cover 84. The bottom end of the branch pipe 16 passes through the inner wall of the bottom end of the protective shell 81 and extends into the interior of the protective shell 81. The bottom of the protective shell 81 is filled with an absorbent liquid layer 17. A liquid guide block 18 is fixedly connected to the inner wall of the protective shell 81. An opening that matches both ends of the valve body 1 is opened at the bottom end of the liquid guide block 18. The bottom end of the liquid guide block 18 is located in the absorbent liquid layer 17.

[0035] The outer wall of the phosgene leak prevention mechanism 8 is fixedly connected to an outer cover 11. The top of the outer cover 11 is fixedly embedded with a first sealing bearing 12. The inner wall of the first sealing bearing 12 is fixedly connected to a connecting hose 13. The top of the connecting hose 13 is fixedly connected to a threaded cap 14 for fixing the handwheel 5. The top of the hollow valve stem 4 is provided with a connecting thread that matches the thread on the inner wall of the threaded cap 14. The bottom of the outer cover 11 is fixedly connected to a normally closed solenoid valve 15. The bottom of the normally closed solenoid valve 15 is fixedly connected to a branch pipe 16.

[0036] The outer wall of the outer cover 11 is fixedly connected to a sealing failure alarm mechanism 9. The sealing failure alarm mechanism 9 includes a fixed shell 91 fixedly connected to the outer wall of the outer cover 11. An audible and visual alarm 92 is fixedly connected to the outer wall of the fixed shell 91. A controller 93 is fixedly connected to the outer wall of the outer cover 11 located at the fixed shell 91. Two through holes are opened on the outer wall of the outer cover 11 located at the fixed shell 91, and a pressure sensor 94 and a phosgene sensor 95 are fixedly connected to the walls of the two through holes.

[0037] The outer cover 11 has a mounting through hole on its side wall, and a one-way air inlet 19 is fixedly connected to the wall of the mounting through hole. A sealing ring 20 is movably sleeved at the joint between the hollow valve stem 4 and the threaded cap 14. A gasket ring 21 is fixedly connected to the bottom end of the threaded cap 14. A fixing flange 22 that mates with the valve cover assembly 3 is fixedly connected to the upper surface of the valve body 1. Both the inlet and outlet ends of the valve body 1 are fixedly connected to connecting flanges 23.

[0038] The barometric pressure sensor 94 and the luminous pressure sensor 95 are electrically connected to the input terminal of the controller 93 via wires. The audible and visual alarm 92 and the normally closed solenoid valve 15 are electrically connected to the output terminal of the controller 93 via wires. The controller 93 is an 80C51 microcontroller. The above-mentioned power-conducting components and electrical connections are all existing technologies and will not be described in detail here.

[0039] The corrosion-resistant rubber valve core 6, corrosion-resistant rubber sleeve 72, corrosion-resistant rubber sealing cover 84, and connecting hose 13 are all made of polytetrafluoroethylene modified rubber. Polytetrafluoroethylene modified rubber combines corrosion resistance and elasticity, solving the problem of easy deformation of the sealing surface, and can resist the erosion and corrosion of phosgene. The liquid guide block 18 is made of porous perfluoroether rubber sponge. After foaming, this material has uniform pores, high water absorption rate, and strong acid and corrosion resistance, ensuring the reliability of the shut-off valve.

[0040] The operating principle of the present invention is described as follows: When the shut-off valve is installed, the connecting thread at the top of the hollow valve stem 4 is precisely matched with the inner thread of the threaded cap 14. At the same time, the threaded cap 14 is securely and sealed to the top of the hollow valve stem 4 through the sealing ring 20 and the gasket ring 21 to ensure that there is no leakage risk at the connection. Then, the air pressure value inside the outer cover 11 is displayed in real time through an external auxiliary device (such as a display screen). After that, a certain amount of air is injected into the outer cover 11 through the one-way air inlet 19. On the one hand, this ensures that there is enough air in the air supply mechanism 7 for the opening and closing of the corrosion-resistant rubber valve core 6. On the other hand, it causes the expansion cavity 10 of the corrosion-resistant rubber valve core 6 to expand slightly, thus having a certain buffering capacity in advance. The air injection process is monitored in real time by the air pressure sensor 94 and the external auxiliary device. The stable air pressure inside the outer cover 11 after air injection is set as the air pressure reference threshold for the sealing failure alarm, so as to avoid the air pressure inside the air supply mechanism 7 being too high and interfering with the sealing effect or too low and affecting the buffering function.

[0041] Subsequently, as the gas-liquid dual-phase phosgene passes through the inlet of valve body 1, through the flow hole of valve seat 2, and then exits from the outlet of valve body 1, if air hammer occurs due to pressure fluctuations or rapid valve opening and closing, the impact force of the air hammer will directly act on the corrosion-resistant rubber valve core 6 through the gas-liquid dual-phase phosgene. Since the corrosion-resistant rubber valve core 6 has slightly expanded and possesses elastic deformation capability, it will deform rapidly after being impacted, achieving the first layer of buffering through its own elasticity. At the same time, the deformation process will compress the air in the expansion cavity 10, causing the air to flow back along the internal channel of the hollow valve stem 4 and the air inlet 74 into the corrosion-resistant rubber sleeve 72, pushing the corrosion-resistant rubber sleeve 72. The expansion deformation allows the corrosion-resistant rubber sleeve 72 to fit more tightly against the inner wall of the top of the valve body 1, which not only improves the sealing performance of the top of the valve body 1, but also forms a second buffer through the deformation resistance of the corrosion-resistant rubber sleeve 72. This significantly reduces the damage to the internal structure of the gate valve caused by the impact of air hammer. After the air hammer phenomenon, the impact force of the medium on the corrosion-resistant rubber valve core 6 gradually decreases. The air supply mechanism 7 and the corrosion-resistant rubber valve core 6 return to their initial state under the action of their own elasticity and air flow. This mechanism gives the gate valve the function of impact buffering, effectively improving the protection capability of the gate valve, thereby extending the service life of the gate valve and ensuring the stable operation of the phosgene pipeline system.

[0042] When the shut-off valve, through the handwheel 5 and hollow valve stem 4, drives the corrosion-resistant rubber valve core 6 to close with the flow hole of the valve seat 2, rotating the handwheel 5 causes the hollow valve stem 4 to rotate on the valve cover assembly 3. The valve cover assembly 3, in conjunction with the lifting thread on the hollow valve stem 4, pushes the corrosion-resistant rubber valve core 6 downward, causing the corrosion-resistant rubber valve core 6 to gradually approach and insert into the flow hole of the valve seat 2. At the same time, the hollow valve stem 4, through the support ring 71, drives the corrosion-resistant rubber sleeve 72 to move downward synchronously. When the corrosion-resistant rubber sleeve 72 moves to the position of the inclined extrusion ring 73, it is resisted by the inclined extrusion ring 73. Due to the restriction, the corrosion-resistant rubber sleeve 72 will undergo significant compression deformation. After being compressed, the air inside the corrosion-resistant rubber sleeve 72 is injected into the expansion cavity 10 through the air inlet 74 and the internal channel of the hollow valve stem 4, causing the corrosion-resistant rubber valve core 6 to expand rapidly. The expanded corrosion-resistant rubber valve core 6 is in the shape of an "I" and is tightly attached to the top surface, bottom surface and wall of the flow hole of the valve seat 2, achieving multiple seals for the flow hole of the valve seat 2 and greatly improving the sealing effect. This mechanism enables the gate valve to have multiple sealing functions when closed, significantly improving the reliability of the gate valve's closing seal.

[0043] If a phosgene leaks due to a sealing failure at the connection between the valve cover assembly 3 and the valve body 1 via the fixed flange 22, the leaking phosgene will be confined by the closed space formed by the protective shell 81 and the corrosion-resistant rubber sealing cover 84, making it difficult for it to diffuse to the outside. Moreover, due to the strong water absorption properties of the liquid guide block 18, the bottom of the liquid guide block 18 can be continuously kept moist by being immersed in the absorbent liquid layer 17 (such as water or alkaline solution). When the leaking phosgene comes into contact with the solution in the liquid guide block 18, it will be reacted and treated. For example, phosgene reacts with water to generate an acidic solution and carbon dioxide. The accumulation of carbon dioxide will push the corrosion-resistant rubber sealing cover 84 to bulge outward, forming a direct leakage warning signal to remind the production site staff that a leakage accident has occurred and emergency maintenance is required. During the maintenance process, the staff must wear professional protective equipment (such as gas masks and chemical protective clothing) and cooperate with air purification equipment to avoid contact with harmful gases and injury. This mechanism enables the gate valve to have a phosgene leakage prevention function, which greatly improves the protective performance of the gate valve.

[0044] As the service life of the gate valve increases, the surface of the corrosion-resistant rubber valve core 6 will be damaged due to erosion and wear by the medium, leading to the failure of the gate valve's closure seal. At this time, the seal failure alarm mechanism 9 will activate the corresponding alarm process according to the leakage location. If the corrosion-resistant rubber valve core 6 is damaged and leaks on the surface of the valve body 1 inlet side, the gas-liquid two-phase phosgene on the valve body 1 inlet side will seep into the expansion cavity 10 through the damaged and leaking point, and then enter the outer cover 11 along the internal channel of the hollow valve stem 4. At this time, after the phosgene sensor 95 detects the phosgene in the outer cover 11, it immediately converts the detection signal into an electrical signal and transmits it to the controller 93. The controller 93 then... The received electrical signal synchronously controls two operations: First, it controls the normally closed solenoid valve 15 to open, allowing the gas-liquid two-phase phosgene inside the outer casing 11 to be injected into the absorbent liquid layer 17 (such as water or alkaline solution) of the protective shell 81 through the branch pipe 16. The phosgene is easily soluble in water, so it is quickly absorbed and its diffusion is avoided. If the absorbent liquid layer 17 is an alkaline solution, the phosgene dissolves in the water in the alkaline solution and produces an acidic solution. The acidic solution can then neutralize the alkaline solution, minimizing the harm caused by phosgene leakage. Second, it activates the audible and visual alarm 92, emitting a clear audible and visual alarm signal to remind maintenance personnel to handle the emergency.

[0045] If the surface of the corrosion-resistant rubber valve core 6 at the outlet side of the valve body 1 is damaged and leaks, since there is no gas-liquid two-phase phosgene obstruction at the outlet side of the valve body 1, the reserved air in the gas supply mechanism 7 and the expansion cavity 10 will leak to the outlet side of the valve body 1 through the damaged leak, causing the air pressure inside the outer casing 11 to drop. The air pressure sensor 94 captures the air pressure change in real time and converts it into an electrical signal and sends it to the controller 93. When the air pressure inside the outer casing 11 is lower than the air pressure reference threshold for the controller 93 to alarm the seal failure, the controller 93 will immediately control the audible and visual alarm 92 to alarm, reminding maintenance personnel to repair the shut-off valve in time to avoid the leakage from expanding and causing a larger safety accident. This mechanism enables the shut-off valve to have real-time monitoring and accurate alarm functions for seal failure, which can effectively avoid safety accidents caused by a large amount of phosgene leakage and significantly improve the safety and reliability of valve operation.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bellows shut-off valve for phosgene pipelines, comprising a valve body (1), a valve seat (2), a valve cover assembly (3), a hollow valve stem (4), and a handwheel (5), wherein the outer wall of the hollow valve stem (4) is provided with a lifting thread that mates with the valve cover assembly (3), characterized in that, The bottom end of the hollow valve stem (4) is fixedly sleeved with a corrosion-resistant rubber valve core (6) that cooperates with the valve seat (2). The corrosion-resistant rubber valve core (6) has an expansion cavity (10) inside, and the expansion cavity (10) is connected to the opening at the bottom of the hollow valve stem (4). The hollow valve stem (4) is fixedly sleeved with an air supply mechanism (7). The outer wall of the valve body (1) is fixedly sleeved with a phosgene anti-leakage mechanism (8); The outer wall of the phosgene leak prevention mechanism (8) is fixedly connected to an outer cover (11). The top of the outer cover (11) is fixedly embedded with a first sealing bearing (12). The inner wall of the first sealing bearing (12) is fixedly connected to a connecting hose (13). The top of the connecting hose (13) is fixedly connected to a threaded cap (14) for fixing the handwheel (5). The top of the hollow valve stem (4) is provided with a connecting thread that matches the threaded thread on the inner wall of the threaded cap (14). The bottom of the outer cover (11) is fixedly connected to a normally closed solenoid valve (15). The bottom of the normally closed solenoid valve (15) is fixedly connected to a branch pipe (16). The outer wall of the outer cover (11) is fixedly connected to a sealing failure alarm mechanism (9); The phosgene leak prevention mechanism (8) includes a protective shell (81) fixedly sleeved to the outer wall of the valve body (1). The top of the protective shell (81) is provided with a fixed slot, and a sealing gasket (82) is sleeved on the groove wall of the fixed slot. The top of the protective shell (81) is fixedly connected to a top cover (83) by bolts. A corrosion-resistant rubber sealing cover (84) is fixedly connected to the inner wall of the top cover (83). A second sealing ring (85) is fixedly sleeved on the rod wall of the hollow valve stem (4). The outer wall of the second sealing ring (85) is fixedly connected to the inner wall of the top of the corrosion-resistant rubber sealing cover (84). The bottom end of the branch pipe (16) passes through the inner wall of the bottom end of the protective shell (81) and extends into the interior of the protective shell (81). The bottom of the protective shell (81) is filled with an absorbent liquid layer (17), and a liquid guide block (18) is fixedly connected to the inner wall of the protective shell (81). The bottom end of the liquid guide block (18) is provided with an opening that matches the two ends of the valve body (1). The bottom end of the liquid guide block (18) is located in the absorbent liquid layer (17). The sealing failure alarm mechanism (9) includes a fixed shell (91) fixedly connected to the outer wall of the outer cover (11). An audible and visual alarm (92) is fixedly connected to the outer wall of the fixed shell (91). A controller (93) is fixedly connected to the outer wall of the outer cover (11) located at the fixed shell (91). Two through holes are opened on the outer wall of the outer cover (11) located at the fixed shell (91), and a pressure sensor (94) and a phosgene sensor (95) are fixedly connected to the hole walls of the two through holes.

2. The bellows shut-off valve for phosgene pipelines according to claim 1, characterized in that, The gas supply mechanism (7) includes a support ring (71) fixedly sleeved to the outer wall of the hollow valve stem (4). A corrosion-resistant rubber sleeve (72) is fixedly sleeved to the outer wall of the support ring (71). The bottom end of the corrosion-resistant rubber sleeve (72) is fixedly sleeved to the outer wall of the hollow valve stem (4). The top outer wall of the corrosion-resistant rubber sleeve (72) is sealed and slidably connected to the top inner wall of the valve body (1). A beveled extrusion ring (73) that cooperates with the corrosion-resistant rubber sleeve (72) is fixedly connected to the top inner wall of the valve body (1). An air inlet hole (74) is opened on the outer wall of the hollow valve stem (4) located at the corrosion-resistant rubber sleeve (72).

3. A bellows shut-off valve for phosgene pipelines according to claim 1, characterized in that, The outer cover (11) has an installation through hole on its side wall, and a one-way air inlet (19) is fixedly connected to the hole wall of the installation through hole.

4. A bellows shut-off valve for phosgene pipelines according to claim 1, characterized in that, A sealing ring (20) is movably sleeved at the joint between the hollow valve stem (4) and the threaded cap (14), and a gasket ring (21) is fixedly connected to the bottom end of the threaded cap (14).

5. A bellows shut-off valve for phosgene pipelines according to claim 1, characterized in that, The upper surface of the valve body (1) is fixedly connected to a fixed flange (22) that cooperates with the valve cover assembly (3), and the inlet and outlet ends of the valve body (1) are both fixedly connected to connecting flanges (23).

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