Explosion-proof pressure relief device for acetic anhydride storage tank

Abstract

The invention relates to the technical field of acetic anhydride storage, and provides an acetic anhydride storage tank anti-explosion pressure relief device which comprises a blocking block, a valve body, a valve cover and a valve element. The valve body comprises an outer valve seat and an inner valve seat, a pressure relief cavity is formed in the inner valve seat, and the valve element is arranged in the pressure relief cavity in a sliding mode. A spiral flow guide cavity is formed in the blocking block, a communicating cavity is formed in the valve element, and a low-pressure cavity, a medium-pressure cavity and a high-pressure cavity are formed between the valve element and the inner valve seat from bottom to top in sequence. A gas-liquid separation cavity is formed in the valve deck, the communicating cavity communicates with the spiral flow guide cavity and the low-pressure cavity, and the high-pressure cavity communicates with the gas-liquid separation cavity. A liquid return pipe is arranged on the valve cover in the radial direction, the other end of the liquid return pipe is connected to the position below the feeding port of the tank body, and a one-way valve is arranged on the liquid return pipe. When the valve element moves from bottom to top, the elastic piece is compressed to store energy, and the low-pressure cavity is firstly communicated with the medium-pressure cavity. The pressure relief device adapts to acetic anhydride storage pressure gradient change, and stable and smooth pressure relief is achieved.

Description

Technical Field

[0001] This invention relates to the field of acetic anhydride storage technology, and in particular to an explosion-proof pressure relief device for acetic anhydride storage tanks. Background Technology

[0002] Acetic anhydride is an important organic chemical raw material widely used in the pharmaceutical, dye, fragrance, and plastics industries. It is a colorless, transparent liquid at room temperature and pressure and is volatile. During storage, acetic anhydride is typically stored in sealed tanks. Due to factors such as changes in ambient temperature, the evaporation of the medium itself, and trace chemical reactions within the tank, the pressure inside the tank is prone to fluctuations. If the pressure exceeds the tank's capacity, it can lead to safety accidents such as explosions and leaks.

[0003] Existing explosion-proof pressure relief devices for storage tanks mostly use traditional spring-loaded safety valves or rupture discs. Acetic anhydride is highly volatile during storage, and when depressurized, it carries a large amount of liquid, which, if directly discharged, will cause material loss and environmental pollution. Furthermore, during acetic anhydride storage, the pressure inside the tank is not constant but varies with ambient temperature and the rate of evaporation. During depressurization, when a slight pressure fluctuation occurs inside the tank, once the depressurization conditions are met, the pressure relief channel fully opens, and a large amount of volatile acetic anhydride vapor leaks rapidly. This not only causes the loss of valuable media, but the leaked vapor also hydrolyzes with moisture in the air to form highly corrosive acetic acid, corroding surrounding equipment and pipelines.

[0004] When the pressure inside the tank suddenly becomes high, existing pressure relief methods cannot quickly release the high pressure. The pressure relief rate lags behind the pressure rise rate, which can easily cause the pressure inside the storage tank to exceed its bearing capacity, leading to serious safety accidents such as explosions and leaks. In addition, traditional safety valves experience a large pressure surge at the moment of opening, which can easily cause valve core vibration and damage to the sealing surface, resulting in an unstable pressure relief process and poor safety stability. Summary of the Invention

[0005] In view of this, the present invention aims to provide an explosion-proof pressure relief device for acetic anhydride storage tanks, which can adapt to the storage characteristics of acetic anhydride and the working conditions of pressure gradient changes, so as to achieve stable and gentle pressure relief and ensure safety.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows: An explosion-proof pressure relief device for an acetic anhydride storage tank includes a block located on the upper part of the tank body, a valve body connected to the block, a valve cover sleeved on the valve body, and a valve core located in the inner cavity of the valve body. The valve body includes an outer valve seat and an inner valve seat. The inner valve seat has a pressure relief chamber extending through its height, and the valve core is slidably disposed within the pressure relief chamber. A spiral flow guiding chamber is formed within the plug, and a communicating chamber is formed within the valve core. A low-pressure chamber, a medium-pressure chamber, and a high-pressure chamber are formed between the valve core and the inner valve seat, arranged sequentially from bottom to top. A gas-liquid separation chamber is formed within the valve cover. The communicating chamber communicates with the spiral flow guiding chamber and the low-pressure chamber, respectively, and the high-pressure chamber communicates with the gas-liquid separation chamber. An air outlet is provided at the top of the valve cover, and a return pipe for collecting liquid is provided radially on the valve cover. The other end of the return pipe is connected to the bottom of the feed inlet of the tank, and a one-way valve is provided on the return pipe. An elastic element is provided between the valve core and the valve cover. When the valve core is driven to move upward by the high-pressure fluid, the elastic element is compressed and stores energy, and the low-pressure chamber is first connected to the medium-pressure chamber. When the valve core continues to move upward, the low-pressure chamber, the medium-pressure chamber and the high-pressure chamber are connected simultaneously. When the high-pressure fluid is depressurized, the elastic element releases energy and drives the valve core to reset.

[0007] Furthermore, the outer wall of the valve core is formed with a stepped sealing platform, and the inner wall of the pressure relief chamber is formed with a stepped sealing surface that matches the sealing platform. The low-pressure chamber, medium-pressure chamber, and high-pressure chamber are formed by the sealing platform and the sealing surface in combination.

[0008] Furthermore, the tank body is formed with a conformally shaped cavity, the block includes a block with an opening facing downwards and a blocking plate for sealing the opening of the block, the inner wall of the block is formed with a spiral groove arranged from bottom to top, and the blocking plate and the block enclose to form the spiral flow guiding cavity; the blocking plate is formed with a through flow hole, and the flow hole connects the cavity and the spiral flow guiding cavity.

[0009] Furthermore, the outer valve seat includes a mounting plate and a cylindrical body vertically connected to the mounting plate, the cylindrical body being formed into a cylindrical structure with a cavity; The inner valve seat includes, from top to bottom, a top block, a first sealing block, a second sealing block, a third sealing block, a connecting block, and a bottom block; The bottom block abuts against the mounting plate, and the sealing surface is formed on the inner wall of the first sealing block and the second sealing block.

[0010] Furthermore, the valve core includes, from top to bottom, a guide section, a first conical section, a first sealing section, a second sealing section, a second conical section, and a third sealing section; When the valve core is in the initial position, a low-pressure chamber is formed between the second conical section, the second sealing block, and the third sealing block. The second sealing section abuts against the first sealing block and the second sealing block, and a first sealing ring is provided at the junction of the first sealing block and the second sealing block. The first sealing ring is used to restrict the communication between the low-pressure chamber and the medium-pressure chamber when the valve core is in the initial position.

[0011] Furthermore, an annular cavity is formed inside the first sealing block, and the annular cavity and the second sealing section together form the medium-pressure cavity, wherein the maximum diameter of the annular cavity is greater than the maximum diameter of the pressure relief cavity; When the valve core is in the initial position, the first sealing section and the second sealing section simultaneously abut against the first sealing block; A second sealing ring is provided between the first sealing block and the first sealing section. The second sealing ring is used to restrict the communication between the medium-pressure chamber and the high-pressure chamber when the valve core is in the initial position.

[0012] Furthermore, a third conical section is provided between the first sealing section and the second sealing section, and the diameter of the third conical section gradually decreases from top to bottom.

[0013] Furthermore, the second conical segment includes an inverted conical segment, a guide segment, and a straight conical segment arranged sequentially from top to bottom; The diameter of the guide section is the smallest, the diameter of the inverted cone section gradually decreases from top to bottom, and the diameter of the upright cone section gradually increases from top to bottom; The slope of the inverted cone section is greater than that of the upright cone section, so that the valve core obtains a smaller pressure relief area in the initial opening stage and a larger pressure relief area in the main pressure relief stage.

[0014] Furthermore, the valve cover includes a cap and a positioning member screwed into the cap, wherein a spirally descending return channel is formed within the positioning member; The top block has a through cavity formed inside, the lower part of the positioning member is inserted into the through cavity, the lower part of the through cavity forms the high pressure chamber, the inner cavity inside the positioning member forms the gas-liquid separation chamber, and the gas-liquid separation chamber is divided into a lower air intake buffer zone and an upper exhaust zone. The positioning component is also pivotally connected to a swirl plate in the middle, and the swirl plate has multiple through exhaust holes. The outlet of the return channel is connected to the return pipe. When the high-pressure fluid is injected at high speed from the high-pressure chamber into the air intake buffer and impacts the swirl plate, the gas phase carries some tiny droplets through the exhaust hole into the exhaust zone, and the liquid droplets impact the swirl plate due to inertia and are impacted by the swirl plate to form a liquid film on the inner wall of the positioning member. The liquid film flows through the return channel into the return pipe.

[0015] Compared with the prior art, the present invention has the following advantages: The acetic anhydride storage tank explosion-proof pressure relief device of the present invention forms a graded structure of low-pressure chamber, medium-pressure chamber and high-pressure chamber through the cooperation of valve core and inner valve seat. The spiral guide chamber located in the tank is connected to the low-pressure chamber. When the pressure reaches the pressure relief condition, the fluid passes through each chamber to reduce the pressure impact, avoid valve core vibration and sealing surface damage. Moreover, the pressure relief flow rate can be flexibly adjusted according to the pressure fluctuation amplitude in the tank, and the pressure relief area can be adjusted according to the position of valve core displacement. This not only avoids a large amount of steam leakage when there is a small amount of pressure relief, but also enables a large flow rate for rapid pressure relief at high pressure. It solves the problems after pressure relief in traditional devices, effectively avoids the hidden danger of overpressure explosion of the storage tank, and can adapt to the pressure gradient change conditions of acetic anhydride storage.

[0016] Meanwhile, a gas-liquid separation chamber and a swirl plate are installed inside the valve cover to efficiently separate the gas and liquid phases during the depressurization process. The separated acetic anhydride liquid flows back to the tank through the return pipe and one-way valve, realizing material recovery and avoiding the risk of corrosion to external equipment caused by the co-ejection of gas and liquid. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a cross-sectional schematic diagram showing the connection between the explosion-proof pressure relief device for the acetic anhydride storage tank and the tank body according to an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the explosion-proof pressure relief device for the acetic anhydride storage tank according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Tank body; 2. Plug; 3. Valve body; 4. Valve cover; 5. Valve core; 6. Low-pressure chamber; 7. Medium-pressure chamber; 8. High-pressure chamber; 9. First sealing ring; 10. Second sealing ring; 11. Check valve; 12. Elastic element; 13. Spiral guide chamber; 31. Outer valve seat; 32. Top block; 33. First sealing block; 34. Second sealing block; 35. Third sealing block; 36. Connecting block; 37. Bottom block; 41. Cap; 42. Positioning component; 43. Return pipe; 44. Air outlet; 51. Guide section; 52. First conical section; 53. First sealing section; 54. Second sealing section; 55. Second conical section; 56. Third sealing section; 57. Third conical section; 58. Communicating cavity; Mounting plate; 312, cylinder body; 421. Reflux channel; 422. Gas-liquid separation chamber; 423. Swirl plate; 551. Inverted cone section; 552. Guide section; 553. Positive cone section; 331. Annular cavity; 4231. Exhaust port. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0020] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "back," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] Furthermore, in the description of this invention, unless otherwise explicitly defined, the terms "installation," "connection," "linking," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in light of the specific circumstances.

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] This embodiment relates to an explosion-proof pressure relief device for an acetic anhydride storage tank. Overall, as follows... Figure 1 As shown, the device includes a plug 2 located on the upper part of the tank 1, a valve body 3 connected to the plug 2, a valve cover 4 sleeved on the valve body 3, and a valve core 5 located in the inner cavity of the valve body 3. The valve body 3 includes an outer valve seat 31 and an inner valve seat. The inner valve seat is formed with a pressure relief chamber that extends through its height direction. The valve core 5 is slidably disposed in the pressure relief chamber. A spiral guide chamber 13 is formed inside the plug 2, and a connecting chamber 58 is formed inside the valve core 5. A low-pressure chamber 6, a medium-pressure chamber 7, and a high-pressure chamber 8 are formed between the valve core 5 and the inner valve seat, arranged sequentially from bottom to top.

[0024] The valve cover 4 has a gas-liquid separation chamber 422 formed inside. The connecting chamber 58 is connected to the spiral guide chamber 13 and the low-pressure chamber 6 respectively, and the high-pressure chamber 8 is connected to the gas-liquid separation chamber 422. The valve cover 4 has an air outlet 44 at the top and a return pipe 43 for collecting liquid is provided radially. The other end of the return pipe 43 is connected to the bottom of the feed inlet of the tank 1. A one-way valve 11 is provided on the return pipe 43. An elastic element 12 is provided between the valve core 5 and the valve cover 4. When the valve core 5 is driven by the high-pressure fluid to move from bottom to top, the elastic element 12 compresses and stores energy, and the low-pressure chamber 6 is first connected to the medium-pressure chamber 7. When the valve core 5 continues to move upward, the low-pressure chamber 6, the medium-pressure chamber 7 and the high-pressure chamber 8 are connected at the same time. When the high-pressure fluid is depressurized, the elastic element 12 releases energy and drives the valve core 5 to reset.

[0025] Based on the above design concept, the explosion-proof pressure relief device for the acetic anhydride storage tank in this embodiment forms a graded structure of low-pressure chamber 6, medium-pressure chamber 7, and high-pressure chamber 8 through the cooperation of valve core 5 and inner valve seat. The spiral guide chamber 13 located inside the tank is connected to the low-pressure chamber 6. When the pressure reaches the pressure relief condition, the fluid passes through each chamber to reduce the pressure impact, avoid vibration of valve core 5 and damage to the sealing surface, and can flexibly adjust the pressure relief flow rate according to the pressure fluctuation amplitude inside the tank, and adjust the pressure relief area according to the displacement position of valve core 5. This not only avoids a large amount of steam leakage during slight pressure relief, but also enables rapid pressure relief with a large flow rate at high pressure, solving the problems after pressure relief in traditional devices, effectively avoiding the hidden danger of overpressure explosion of the storage tank, and can adapt to the pressure gradient change conditions of acetic anhydride storage.

[0026] Meanwhile, a gas-liquid separation chamber 422 and a swirl plate 423 are set inside the valve cover 4 to efficiently separate the gas phase and liquid phase during the depressurization process. The separated acetic anhydride liquid flows back to the tank 1 through the return pipe 43 and the one-way valve 11 to realize material recovery and avoid the risk of corrosion to external equipment caused by the co-ejection of gas and liquid.

[0027] Based on the above overall concept, an exemplary structure of the acetic anhydride storage tank explosion-proof pressure relief device in this embodiment includes a tank body 1, a plug 2 located on the upper part of the tank body 1, a valve body 3 connected to the plug 2, a valve cover 4 sleeved on the valve body 3, and a valve core 5 located in the inner cavity of the valve body 3. All components that come into contact with acetic anhydride and hydrolysis products are made of stainless steel that is resistant to acetic anhydride corrosion to prevent corrosion failure. At the same time, the inner walls of each fluid channel are polished to prevent the accumulation of acetic anhydride crystals, thus adapting to the highly corrosive characteristics of acetic anhydride.

[0028] As a preferred embodiment, such as Figure 1 and Figure 2As shown, the outer wall of the valve core 5 is formed with a stepped sealing platform, and the inner wall of the pressure relief chamber is formed with a stepped sealing surface that matches the sealing platform. The low-pressure chamber 6, medium-pressure chamber 7, and high-pressure chamber 8 are formed by the mating of the sealing platform and the sealing surface. This arrangement of the valve core 5 and valve seat structure enables orderly staged pressure relief, while the stepped structure adapts to the sliding trajectory of the valve core 5, reducing the wear of the sealing structure caused by fluid impact.

[0029] like Figure 1 and Figure 2 As shown, the tank body 1 has a shaped cavity. The plug 2 includes a block with an opening facing downwards and a plug plate for sealing the opening of the block 2. The inner wall of the block has spiral grooves formed from bottom to top. The plug plate and the block enclose a spiral guide cavity 13. The plug plate has a through flow hole that connects the cavity 58 and the spiral guide cavity 13. By setting a spiral guide cavity 13 with a large area and spiral grooves, the wear of the valve core 5 by fluid impact is reduced, and the fluid flow is guided, alleviating the problem of large pressure impact and easy vibration of the valve core 5 when the pressure relief is opened.

[0030] Preferably, such as Figure 2 As shown, the outer valve seat 31 includes a mounting plate 311 and a cylindrical body 312 vertically connected to the mounting plate 311. The cylindrical body 312 is formed into a cylindrical structure with a cavity. The inner valve seat includes, from top to bottom, a top block 32, a first sealing block 33, a second sealing block 34, a third sealing block 35, a connecting block 36, and a bottom block 37. The bottom block 37 abuts against the top of the mounting plate 311, and the sealing surface is formed on the inner wall of the first sealing block 33 and the second sealing block 34. The inner valve seat is located inside the cylindrical body 312. With the above structural arrangement, it is easy to disassemble and install. The inner valve seat has multiple assembled parts, which can replace individual parts at any time. The valve cover 4 can form a stable overall structure after being squeezed, avoiding loosening of parts due to pressure impact.

[0031] As mentioned above, such as Figure 2 As shown, the pressure relief chamber extends along the height of the inner valve seat. The valve core 5 includes, from top to bottom, a guide section 51, a first conical section 52, a first sealing section 53, a second sealing section 54, a second conical section 55, and a third sealing section 56. When the valve core 5 is in its initial position, a low-pressure chamber 6 is formed between the second conical section 55, the second sealing block 34, and the third sealing block 35. The second sealing section 54 abuts against the first sealing block 33 and the second sealing block 34, and a first sealing ring 9 is provided at the junction of the first sealing block 33 and the second sealing block 34. The first sealing ring 9 is used to restrict the communication between the low-pressure chamber 6 and the medium-pressure chamber 7 when the valve core 5 is in its initial position.

[0032] The elastic element 12, mounted on the guide section 51, is a cylindrical structure. The first conical section 52 ensures a smooth fluid transition, preventing eddies from forming at the guide section 51 and affecting subsequent gas-liquid separation. It also prevents the valve core 5 from vibrating and shifting due to uneven force, thus solving the problem of valve core 5 vibrating easily when the safety valve is opened. The first sealing section 53 has a cylindrical structure, precisely fitting the sealing surface of the inner wall of the first sealing block 33. The second sealing ring 10 cooperates to achieve graded sealing between the medium-pressure chamber 7 and the high-pressure chamber 8, preventing cross-flow and leakage of acetic anhydride medium when there are no pressure fluctuations. When the pressure inside the tank reaches the high-pressure condition, the valve core 5 moves upward, and the first sealing section 53 gradually separates from the first sealing block 33, quickly opening the high-pressure relief channel to ensure rapid flow of high-pressure fluid and avoid high-pressure relief lag.

[0033] The third sealing section 56 is located at the lowest end of the valve core 5 and fits against the inner wall of the third sealing block 35. The three sealing structures further improve the smoothness of the valve core 5's sliding and ensure sliding accuracy. At the same time, the third sealing section 56 forms an auxiliary seal for the low-pressure chamber 6, which, together with the second conical section 55 and the first sealing ring 9, improves the sealing reliability in the initial state and prevents acetic anhydride vapor leakage when there are no pressure fluctuations. After the upper part of the third sealing section 56 rises to its position, it abuts against the third sealing block 35, restricting the movement of the valve core 5 and preventing the valve core 5 from being damaged by impact due to high pressure.

[0034] In addition, such as Figure 2 As shown, an annular cavity 331 is formed within the first sealing block 33. The annular cavity 331 and the second sealing section 54 together form a medium-pressure chamber 7. The maximum diameter of the annular cavity 331 is larger than the maximum diameter of the pressure relief chamber. When the valve core 5 is in the initial position, the first sealing section 53 and the second sealing section 54 simultaneously abut against the first sealing block 33. A second sealing ring 10 is provided between the first sealing block 33 and the first sealing section 53. The second sealing ring 10 is used to restrict the communication between the medium-pressure chamber 7 and the high-pressure chamber 8 when the valve core 5 is in the initial position. The medium-pressure chamber 7 formed by the annular cavity 331 expands the pressure relief channel under medium-pressure conditions, improves the pressure relief efficiency, and adapts to changes in the medium-pressure gradient within the tank.

[0035] As a preferred embodiment, such as Figure 2 As shown, a third conical section 57 is provided between the first sealing section 53 and the second sealing section 54, and the diameter of the third conical section 57 gradually decreases from top to bottom. The upper part of the first sealing block 33 has an inclined surface that gradually increases from bottom to top. The setting of the third conical section 57 and the inclined surface further increases the effective volume and fluid flow space of the high-pressure chamber 8. When a sudden high pressure occurs in the tank and a large amount of fluid rapidly enters the high-pressure chamber 8, the intermediate-pressure chamber 7 can move a short distance to connect with the high-pressure chamber 8, avoiding the lag in high-pressure leakage.

[0036] Furthermore, such as Figure 2As shown, the second conical section 55 includes an inverted conical section 551, a guide section 552, and a straight conical section 553 arranged sequentially from top to bottom. The guide section 552 has the smallest diameter, the diameter of the inverted conical section 551 gradually decreases from top to bottom, and the diameter of the straight conical section 553 gradually increases from top to bottom. The slope of the inverted conical section 551 is greater than that of the straight conical section 553, so that the valve core 5 obtains a smaller pressure relief area in the initial opening stage and a larger pressure relief area in the main pressure relief stage. The inverted conical section 551 is located at the upper part of the second conical section 55. When a slight pressure fluctuation occurs in the tank, the valve core 5 only moves slightly upward. At this time, the pressure relief gap formed between the inverted conical section 551 and the inner wall of the low-pressure chamber 6 is small, and the inclined surface of the inverted conical section 551 can guide the fluid to flow out slowly along the inclined surface, which is convenient for controlling the pressure relief flow rate, releasing only a small amount of excess steam in the tank, avoiding the leakage of a large amount of volatile acetic anhydride vapor, and reducing material loss. Meanwhile, the inclined structure of the inverted cone section 551 can slow down the fluid flow rate, reduce the impact and further ensure the fluid leakage, and also reduce the adhesion of acetic anhydride condensate in the pressure relief gap, avoid the accumulation of crystals, and ensure the reset effect of valve core 5 after pressure relief.

[0037] At the same time, still as Figure 2 As shown, the guide section 552 has a portion with the smallest diameter, which slows down the fluid flow rate, prevents eddies from forming in the two conical sections, reduces the local impact of the fluid on the valve core 5, and avoids vibration of the valve core 5. The positive conical section 553 is located below the second conical section 55, and its diameter gradually increases from top to bottom. The connecting cavity 58 is located on the positive conical section 553. When the valve core 5 is depressurized, the volume of the lower part of the low-pressure chamber 6 decreases. The connecting cavity 58 is located in the lower part of the low-pressure chamber 6, allowing the fluid to directly enter the low-pressure chamber 6 through the connecting cavity 58, avoiding stagnation inside the valve core 5 and reducing the risk of crystallization accumulation.

[0038] As a preferred embodiment, such as Figure 2 As shown, the valve cover 4 includes a cap 41 and a positioning member 42 screwed into the cap 41. A spirally descending return channel 421 is formed within the positioning member 42. A through cavity is formed within the top block 32, and the lower part of the positioning member 42 is inserted into the through cavity. A high-pressure chamber 8 is formed in the lower part of the through cavity. The inner cavity of the positioning member 42 forms a gas-liquid separation chamber 422, which is divided into a lower air intake buffer zone and an upper exhaust zone. A swirl plate 423 is also pivotally connected to the middle of the positioning member 42. Multiple through exhaust holes 4231 are opened on the swirl plate 423. The outlet of the return channel 421 is connected to the return pipe 43.

[0039] like Figure 2As shown, both the positioning element 42 and the cap 41 are rotary structures. The positioning element 42 is stepped, with the smaller diameter end inserted into the upper part of the top block 32. The swirl plate 423 is connected to the middle of the positioning element 42 via a deep groove ball bearing. A positioning sleeve extends from the bottom of the swirl plate 423, and the inner diameter of the positioning sleeve is adapted to the guide section 51. When the valve core 5 moves upward, the elastic element 12 abuts against the lower end of the positioning sleeve. The air outlet 44 on the valve cover 4 and the exhaust hole 4231 on the swirl plate 423 are used to discharge the separated gas. To prevent the liquid phase from being discharged from the exhaust hole 4231, a steam trap is added inside the exhaust hole 4231. The air outlet 44 is a circular through hole formed on the valve cover 4.

[0040] In addition, to ensure that the discharged gas meets environmental emission requirements and to prevent tiny acetic anhydride droplets and impurities from being discharged with the gas and causing environmental pollution, equipment corrosion, or personnel hazards, a filter pad is installed at the gas outlet 44. The filter pad is made of polytetrafluoroethylene material that is resistant to acetic anhydride corrosion and has strong liquid repellency. Its structure is a double-layer composite. The upper layer is a precision filter layer, which is used to efficiently intercept tiny acetic anhydride droplets remaining in the gas. The lower layer is a support filter layer to prevent it from deforming or breaking under the impact of high-pressure gas, ensuring filtration stability. On the other hand, it can further intercept tiny solid impurities that may be carried in the gas. The filter pad is fixed to the inner wall of the gas outlet 44 with a detachable snap-fit ​​structure, which fits tightly with the inner wall of the gas outlet 44 without gaps, preventing the gas from being discharged directly from the gaps without filtration.

[0041] When the high-pressure fluid is injected at high speed from the high-pressure chamber 8 into the intake buffer zone and impacts the swirl plate 423, the gas phase carries some tiny droplets through the exhaust port 4231 into the exhaust zone. The liquid droplets impact the swirl plate 423 due to inertia and are impacted by the swirl plate 423 to the inner wall of the positioning member 42 to form a liquid film. The liquid film flows through the return channel 421 into the return pipe 43.

[0042] In addition, such as Figure 1 and Figure 2 As shown, the connecting cavity 58 has a horizontal section and a vertical section. The horizontal section connects to the low-pressure cavity 6, and the vertical section connects to the spiral guide cavity 13. The bottom of the vertical section is inverted conical, which allows the acetic anhydride fluid in the tank to flow more stably into the connecting cavity 58 after passing through the spiral guide. There is also an arc transition between the horizontal and vertical sections to prevent the fluid from stagnating and crystallizing in the valve core 5 and to improve the smoothness of fluid flow.

[0043] The working process of the explosion-proof pressure relief device for the acetic anhydride storage tank in this embodiment is as follows: The valve core 5 is in its initial position, and the elastic element 12 is in its natural extended state. The first sealing ring 9 restricts the connection between the low-pressure chamber 6 and the medium-pressure chamber 7, and the second sealing ring 10 restricts the connection between the medium-pressure chamber 7 and the high-pressure chamber 8. The acetic anhydride fluid in the tank enters the spiral guide chamber 13 through the cavity and the flow hole. After being stabilized and initially condensed by the spiral guide chamber 13, it enters the low-pressure chamber 6 through the connecting cavity 58 of the valve core 5. At this time, the low-pressure chamber 6 is not connected to the outside world and remains sealed to prevent media leakage.

[0044] When the pressure inside the tank increases slightly, the high-pressure fluid containing acetic anhydride vapor and a small amount of liquid pushes the valve core 5 to move from bottom to top, and the elastic element 12 begins to compress and store energy. When the valve core 5 moves to the first position, the second sealing section 54 disengages from the contact between the first sealing block 33 and the second sealing block 34, the first sealing ring 9 loses its sealing function, the low-pressure chamber 6 connects with the medium-pressure chamber 7, and some fluid enters the medium-pressure chamber 7, achieving a small amount of pressure relief. This avoids the problem of the pressure relief channel being fully opened and a large amount of steam leaking when there is a slight pressure fluctuation in the traditional device, thus reducing material loss and equipment corrosion.

[0045] As the pressure inside the tank continues to rise, the valve core 5 continues to move upward, and the elastic element 12 further compresses and stores energy. When the valve core 5 moves to the second position, the first sealing section 53 disengages from the first sealing block 33, and the second sealing ring 10 cannot seal due to the upward movement. The low-pressure chamber 6, the medium-pressure chamber 7, and the high-pressure chamber 8 are simultaneously connected, and a large amount of high-pressure fluid rapidly enters the high-pressure chamber 8, and then enters the air intake buffer zone of the gas-liquid separation chamber 422 through the through-cavity, realizing rapid pressure relief of high pressure, solving the problem of delayed pressure relief in traditional devices, and ensuring the safety of the storage tank.

[0046] High-pressure fluid is injected at high speed from the high-pressure chamber 8 into the air intake buffer zone and impacts the swirl plate 423. The swirl plate 423 rotates slightly with the fluid, causing the fluid to form a swirling flow. The gas phase carries some tiny droplets through the exhaust port 4231 into the exhaust zone and is finally discharged from the exhaust port 44. The liquid droplets impact the swirl plate 423 due to inertia and are impacted by the swirl plate 423 to form a liquid film on the inner wall of the positioning member 42. Under the action of gravity, the liquid film flows downward along the inner wall of the positioning member 42 and enters the spirally descending return channel 421. Then, it flows back to the bottom of the feed port of the tank 1 through the return pipe 43 and the one-way valve 11, realizing the recovery of acetic anhydride liquid and reducing material loss and environmental pollution.

[0047] Once the high-pressure fluid inside the tank has been depressurized and the pressure inside the tank has returned to normal, the elastic element 12 releases energy, driving the valve core 5 to reset from top to bottom to its initial position along the pressure relief chamber. The first sealing ring 9 and the second sealing ring 10 re-seal the tank, and the low-pressure chamber 6, medium-pressure chamber 7, and high-pressure chamber 8 are separated again. The device returns to its initial sealed state, awaiting the next pressure relief. The stabilizing reset function of the elastic element 12 prevents the valve core 5 from jamming or vibrating, ensuring reliable sealing and improving the safety and stability of the device.

[0048] 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. An explosion-proof pressure relief device for an acetic anhydride storage tank, characterized in that: It includes a block (2) located on the upper part of the tank (1), a valve body (3) connected to the block (2), a valve cover (4) sleeved on the valve body (3), and a valve core (5) located in the inner cavity of the valve body (3). The valve body (3) includes an outer valve seat (31) and an inner valve seat. The inner valve seat is formed with a pressure relief cavity that extends through its height direction. The valve core (5) is slidably disposed in the pressure relief cavity. The plug (2) has a spiral guide cavity (13) formed inside, the valve core (5) has a connecting cavity (58) formed inside, and a low-pressure cavity (6), a medium-pressure cavity (7) and a high-pressure cavity (8) are formed between the valve core (5) and the inner valve seat, arranged sequentially from bottom to top. The valve cover (4) has a gas-liquid separation chamber (422) formed inside. The connecting chamber (58) is connected to the spiral guide chamber (13) and the low-pressure chamber (6) respectively. The high-pressure chamber (8) is connected to the gas-liquid separation chamber (422). The valve cover (4) has an air outlet (44) at the top. The valve cover (4) has a return pipe (43) for collecting liquid in the radial direction. The other end of the return pipe (43) is connected to the bottom of the feed inlet of the tank (1). The return pipe (43) is equipped with a one-way valve (11). An elastic element (12) is provided between the valve core (5) and the valve cover (4). When the valve core (5) is driven by the high-pressure fluid to move from bottom to top, the elastic element (12) is compressed and stored. The low-pressure chamber (6) is first connected to the medium-pressure chamber (7). When the valve core (5) continues to move upward, the low-pressure chamber (6), the medium-pressure chamber (7), and the high-pressure chamber (8) are connected simultaneously. When the high-pressure fluid is depressurized, the elastic element (12) releases energy to drive the valve core (5) to reset.

2. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 1, characterized in that: The outer wall of the valve core (5) is formed with a stepped sealing platform, and the inner wall of the pressure relief chamber is formed with a stepped sealing surface that matches the sealing platform. The low-pressure chamber (6), medium-pressure chamber (7), and high-pressure chamber (8) are formed by the sealing platform and the sealing surface in combination.

3. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 2, characterized in that: The tank (1) has a cavity formed in a conformal manner. The block (2) includes a block with an opening facing downward and a blocking plate for sealing the opening of the block. The inner wall of the block has a spiral groove formed from bottom to top. The blocking plate and the block enclose the spiral guide cavity (13). The blocking plate is formed with a through flow hole, which connects the cavity and the spiral guide cavity (13).

4. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 3, characterized in that: The outer valve seat (31) includes a mounting plate (311) and a cylindrical body (312) vertically connected to the mounting plate (311), the cylindrical body (312) being formed into a cylindrical structure with a cavity; The inner valve seat includes a top block (32), a first sealing block (33), a second sealing block (34), a third sealing block (35), a connecting block (36), and a bottom block (37) arranged sequentially from top to bottom. The bottom block (37) abuts against the mounting plate (311), and the sealing surface is formed on the inner wall of the first sealing block (33) and the second sealing block (34).

5. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 3, characterized in that: The valve core (5) includes a guide section (51), a first conical section (52), a first sealing section (53), a second sealing section (54), a second conical section (55), and a third sealing section (56) arranged sequentially from top to bottom. When the valve core (5) is in the initial position, a low-pressure chamber (6) is formed between the second conical section (55), the second sealing block (34), and the third sealing block (35). The second sealing section (54) abuts against the first sealing block (33) and the second sealing block (34), and a first sealing ring (9) is provided at the junction of the first sealing block (33) and the second sealing block (34). The first sealing ring (9) is used to restrict the communication between the low-pressure chamber (6) and the medium-pressure chamber (7) when the valve core (5) is in the initial position.

6. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 5, characterized in that: The first sealing block (33) has an annular cavity (331) formed inside. The annular cavity (331) and the second sealing section (54) together form the medium pressure cavity (7). The maximum diameter of the annular cavity (331) is greater than the maximum diameter of the pressure relief cavity. When the valve core (5) is in the initial position, the first sealing section (53) and the second sealing section (54) simultaneously abut against the first sealing block (33); A second sealing ring (10) is provided between the first sealing block (33) and the first sealing section (53). The second sealing ring (10) is used to restrict the communication between the medium pressure chamber (7) and the high pressure chamber (8) when the valve core (5) is in the initial position.

7. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 6, characterized in that: A third conical section (57) is provided between the first sealing section (53) and the second sealing section (54), and the diameter of the third conical section (57) gradually decreases from top to bottom.

8. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 5, characterized in that: The second conical section (55) includes an inverted conical section (551), a guide section (552), and a straight conical section (553) arranged sequentially from top to bottom; The diameter of the guide section (552) is the smallest, the diameter of the inverted cone section (551) gradually decreases from top to bottom, and the diameter of the upright cone section (553) gradually increases from top to bottom; The slope of the inverted cone section (551) is greater than that of the positive cone section (553), so that the valve core (5) obtains a smaller pressure relief area in the initial opening stage and a larger pressure relief area in the main pressure relief stage.

9. The explosion-proof pressure relief device for acetic anhydride storage tank according to claim 4, characterized in that: The valve cover (4) includes a cap (41) and a positioning member (42) screwed into the cap (41), wherein a spirally descending return channel (421) is formed in the positioning member (42). The top block (32) has a through cavity formed inside, and the lower part of the positioning member (42) is inserted into the through cavity. The lower part of the through cavity forms the high pressure chamber (8), and the inner cavity inside the positioning member (42) forms the gas-liquid separation chamber (422). The gas-liquid separation chamber (422) is divided into a lower air intake buffer zone and an upper exhaust zone. The positioning component (42) is also pivotally connected to a swirl plate (423) in the middle. The swirl plate (423) has multiple through exhaust holes (4231). The outlet of the return channel (421) is connected to the return pipe (43). When the high-pressure fluid is injected at high speed from the high-pressure chamber (8) into the air intake buffer and impacts the swirl plate (423), the gas phase carries some tiny droplets through the exhaust hole (4231) into the exhaust zone, and the liquid droplets impact the swirl plate (423) due to inertia, and are impacted by the swirl plate (423) to the inner wall of the positioning member (42) to form a liquid film. The liquid film flows through the return channel (421) into the return pipe (43).

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