Long-time fire retardant structure with intra-cavity flow guide function

Abstract

The invention relates to the field of flame arresters, and discloses a long-time flame arresting structure with an intra-cavity flow guide function, which comprises a shell provided with a pressure relief air inlet end, a pressure relief air outlet end and a cavity; the burning-resistant structure is arranged at the pressure relief exhaust end; and the cavity flow guide structure is arranged in the cavity and is used for dividing pressure relief airflow flowing into the cavity from the pressure relief air inlet end into a plurality of regional airflow flowing towards different regions of the burning-resistant structure. Thus, the cavity flow guide structure can actively divide pressure relief air flow flowing into the cavity from the pressure relief air inlet end, the divided multi-strand regional air flow can flow through different regions of the burning-resistant structure, heat in the burning-resistant structure is dispersed, the risks of tempering and burnthrough phenomena are effectively reduced, the fire retardance duration is effectively prolonged, and the service life of the fire retardant is prolonged. Therefore, the long-time fire-retardant structure can provide long-time burning-resistant protection when accidents such as fire break out at the pressure relief position of the storage tank of the petrochemical device occur, further expansion of the accidents is prevented, and more preparation time is reserved for emergency rescue.

Description

Technical Field

[0001] The present invention belongs to the technical field of flame arresters, and particularly relates to a long-time flame arrestment structure with an in-cavity flow guiding function. Background Art

[0002] During the feeding and discharging process of a storage tank in a petrochemical plant or when the external temperature rises, the gas pressure in the tank will increase. To prevent overpressure damage or pressure buildup of the storage tank, a breather valve is generally installed on the tank top. When there is an ignition source in the external environment, it may ignite the combustible gas exhaled from the storage tank, causing the flame to spread back to the storage tank, thereby triggering a fire or explosion in the storage tank. Therefore, the breather valve needs to have a flame arrestment function, and a product that has undergone an overall flame arrestment test should be selected for an all-weather flame arrestment breather valve.

[0003] However, most of the combustible gases exhaled from the storage tank are premixed combustible gases with high calorific values. Existing pipe-end flame arresters or flame arrestment breather valves generally have problems such as being unable to withstand burning for a long time. As a result, before a long-time burning occurs at the pipe end and effective emergency rescue measures are in place, they cannot provide long-time burning resistance protection, leading to the further expansion of the accident. Summary of the Invention

[0004] The purpose of the present invention is to provide a long-time flame arrestment structure with an in-cavity flow guiding function, which can provide long-time burning resistance protection when an accident such as a fire occurs at the pressure relief position of a storage tank in a petrochemical plant, so as to prevent the further expansion of the accident and leave more preparation time for emergency rescue.

[0005] To achieve the above purpose, the present invention provides a long-time flame arrestment structure with an in-cavity flow guiding function, which includes:

[0006] A housing, provided with a pressure relief air inlet end, a pressure relief air outlet end, and a cavity communicating the pressure relief air inlet end and the pressure relief air outlet end;

[0007] A burning resistance structure, arranged at the pressure relief air outlet end; and

[0008] A cavity flow guiding structure, arranged in the cavity and used for dividing the pressure relief air flow flowing into the cavity from the pressure relief air inlet end into multiple regional air flows flowing in different regions towards the burning resistance structure.

[0009] In some embodiments, the cavity flow guiding structure includes:

[0010] A middle flow guiding member, arranged opposite to the pressure relief air inlet end and used for dividing the pressure relief air flow flowing into the cavity from the pressure relief air inlet end into an outer regional air flow and an inner regional air flow flowing in the outer region and the inner region of the cavity respectively.

[0011] In some embodiments, the middle flow guiding member is provided with a flow-through structure therethrough, and the middle flow guiding member is further configured to divide the pressure relief air flow into an outer ring area air flow, an inner ring area air flow, and a middle area air flow that are sequentially distributed from the outside to the inside in the cavity.

[0012] In some embodiments, the flow-through structure includes a plurality of flow-through holes formed in a middle circular area of the middle flow guiding member.

[0013] In some embodiments, the total flow-through area of the flow-through structure is not greater than one-third of the flow-through area of the pressure relief air inlet end.

[0014] In some embodiments, the middle flow guiding member is a curved plate with the convex surface facing the pressure relief air inlet end.

[0015] In some embodiments, the middle flow guiding member is a pressure relief valve disc for switching the on / off state between the cavity and the pressure relief air inlet end.

[0016] In some embodiments, the axial projection area of the middle flow guiding member is not greater than the axial projection area of the pressure relief air inlet end.

[0017] In some embodiments, the diameter of the middle flow guiding member is D1, the distance between the middle flow guiding member and the inner wall of the upstream end of the cavity is H1, the distance between the middle flow guiding member and the inner wall of the downstream end of the cavity is H2, the inner diameter of the cavity is D, and the inner diameter of the pressure relief air inlet end is d, satisfying:

[0018] wherein e is the natural constant.

[0019] In some embodiments, the cavity flow guiding structure further includes:

[0020] A first annular flow guiding member, disposed on the downstream side of the middle flow guiding member, with an outer circumferential wall of the first annular flow guiding member spaced from the inner circumferential wall of the cavity, and the first annular flow guiding member is configured to further divide the outer side area air flow and the inner side area air flow into an outer ring area air flow, an inner ring area air flow, and a middle area air flow that are sequentially distributed from the outside to the inside in the cavity.

[0021] In some embodiments, the cavity flow guiding structure further includes:

[0022] A second annular flow guiding member, disposed on the downstream side of the first annular flow guiding member, with an outer circumferential wall of the second annular flow guiding member spaced from the inner circumferential wall of the cavity, and the outer ring radius of the second annular flow guiding member is greater than the outer ring radius of the first annular flow guiding member.

[0023] In some embodiments, the cavity flow guiding structure is configured to divide the pressure relief air flow flowing into the cavity into an outer region air flow and an inner region air flow that flow in the outer region and the inner region of the cavity respectively, and to make the flow rate of the outer region air flow greater than that of the inner region air flow, and / or to make the flow rate of the outer region air flow greater than that of the inner region air flow.

[0024] In some embodiments, the cavity flow guiding structure is configured to divide the pressure relief air flow flowing into the cavity into an outer ring region air flow, an inner ring region air flow, and a middle region air flow that are sequentially distributed from the outside to the inside in the cavity, and to make the flow rates of the outer ring region air flow, the middle region air flow, and the inner ring region air flow decrease in sequence, and / or to make the flow rates of the outer ring region air flow, the middle region air flow, and the inner ring region air flow decrease in sequence.

[0025] Through the above technical solution, when the combustible pressure relief air flow continuously discharges through the pressure relief exhaust end and the fire-resistant structure is ignited, the fire-resistant structure will burn for a long time. In the long-time fire-blocking structure of the present invention, due to the setting of the cavity flow guiding structure, compared with the existing fire arrester in which the combustion heat accumulates in a local area (usually the middle area) of the fire-blocking structure, resulting in the combustion heat being difficult to dissipate and even causing the fire-blocking structure to be burned through during the long-time combustion condition, the pressure relief air flow flowing into the cavity from the pressure relief inlet end can be actively shunted, and the multiple divided regional air flows can flow through different regions of the fire-resistant structure, thereby dispersing the heat in the fire-resistant structure, effectively reducing the risk of flashback and burning through, and effectively prolonging the fire-blocking duration. It can be seen that the long-time fire-blocking structure of the present invention can provide long-time fire-resistant protection when an accident such as a fire occurs at the pressure relief position of a storage tank in a petrochemical device, thereby preventing the accident from further expanding and leaving more preparation time for emergency rescue.

[0026] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific embodiments section. Brief Description of the Drawings

[0027] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. They are used together with the following specific embodiments to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts. In the drawings:

[0028] Figure 1 is a schematic diagram of a long-time fire-blocking structure in a specific embodiment of the present invention;

[0029] Figure 2Schematic diagram of another long-time fireproof structure in the specific embodiment of the present invention. The long-time fireproof structure in the figure is provided with two protective side fire-resistant layers;

[0030] Figure 3 Schematic diagram of another long-time fireproof structure in the specific embodiment of the present invention. The long-time fireproof structure in the figure is provided with a middle flow guide member;

[0031] Figure 4 Schematic diagram of another long-time fireproof structure in the specific embodiment of the present invention. The long-time fireproof structure in the figure is provided with a middle flow guide member, and the middle flow guide member is a bent plate with a flow-through structure;

[0032] Figure 5 Axial schematic diagram of a middle flow guide member in the specific embodiment of the present invention. The middle flow guide member in the figure includes a middle circular region provided with a flow-through structure;

[0033] Figure 6 Schematic diagram of a long-time fireproof structure applied as a breather valve in the specific embodiment of the present invention;

[0034] Figure 7 Schematic diagram of a long-time fireproof structure applied as a breathing valve in the specific embodiment of the present invention;

[0035] Figure 8 Schematic diagram of another long-time fireproof structure in the specific embodiment of the present invention. The long-time fireproof structure in the figure is provided with a middle flow guide member and a first annular flow guide member;

[0036] Figure 9 Schematic diagram of another long-time fireproof structure in the specific embodiment of the present invention. The long-time fireproof structure in the figure is provided with a middle flow guide member, a first annular flow guide member and two protective side fire-resistant layers;

[0037] Figure 10 Schematic diagram of another long-time fireproof structure in the specific embodiment of the present invention. The long-time fireproof structure in the figure is provided with a middle flow guide member, a first annular flow guide member and a second annular flow guide member;

[0038] Figure 11 Schematic diagram of the regional air flow distribution in the cavity when a cavity flow guide structure is set for a long-time fireproof structure in the specific embodiment of the present invention;

[0039] Figure 12 Schematic diagram of the regional air flow distribution in the cavity when a cavity flow guide structure is set for another long-time fireproof structure in the specific embodiment of the present invention;

[0040] Figure 13 For Figure 3 Schematic diagram of the structural parameters of the long-time fireproof structure in;

[0041] Figure 14 Schematic diagram of an air inlet end flow guiding structure in a specific embodiment of the present invention;

[0042] Figure 15 Regional air flow distribution diagram in the cavity when a long - time flame retardant structure in a specific embodiment of the present invention is provided with an air inlet end flow guiding structure;

[0043] Figure 16 Regional air flow distribution diagram in the cavity when another long - time flame retardant structure in a specific embodiment of the present invention is provided with an air inlet end flow guiding structure;

[0044] Figures 17 to 19 Axial schematic diagram of three optional heat insulation support structures in a specific embodiment of the present invention;

[0045] Figures 20 to 21 Side view of another two optional heat insulation support structures in a specific embodiment of the present invention;

[0046] Figure 22 Schematic diagram of another long - time flame retardant structure in a specific embodiment of the present invention. In the figure, each refractory layer is provided with a refractory layer outer ring area and a refractory layer inner area, and the refractory layer inner area can be a closed heat insulation area;

[0047] Figure 23 Axial schematic diagram of a refractory layer in a specific embodiment of the present invention. The refractory layer in the figure includes a first closed heat insulation disc and a plurality of first flame retardant discs;

[0048] Figure 24 Schematic diagram of another long - time flame retardant structure in a specific embodiment of the present invention. In the figure, each refractory layer is provided with a refractory layer outer ring area, a refractory layer inner ring area and a refractory layer middle area, and the refractory layer inner ring area can be a closed heat insulation area;

[0049] Figure 25 Axial schematic diagram of another refractory layer in a specific embodiment of the present invention. The refractory layer in the figure includes a flame retardant ring, a closed heat insulation ring and a fourth flame retardant disc;

[0050] Figure 26 Axial schematic diagram of another refractory layer in a specific embodiment of the present invention. The refractory layer in the figure includes a second closed heat insulation disc, a plurality of second flame retardant discs and a single third flame retardant disc;

[0051] Figure 27 Schematic diagram of a stacked porous refractory layer in a specific embodiment of the present invention;

[0052] Figure 28 Schematic diagram of a combustion - side refractory layer in a specific embodiment of the present invention. The combustion - side refractory layer in the figure is provided with a refractory layer disc part and a refractory layer convex part;

[0053] Figure 29 This is a schematic diagram of a fireproof structure for a comparative experiment in a specific embodiment of the present invention. There is no gap left between the fire-resistant layer on the combustion side and the fire-resistant layer on the protection side of the fireproof structure in the figure.

[0054] Description of the reference numerals in the drawings

[0055] 1 Housing;

[0056] 11 Pressure relief air inlet end, 12 Pressure relief air outlet end, 13 Cavity;

[0057] 2 Fire-resistant layer;

[0058] 21a Fire-resistant layer on the combustion side, 21b Fire-resistant layer on the protection side;

[0059] 22a Outer ring area of the fire-resistant layer, 22b Inner ring area of the fire-resistant layer, 22c Intermediate area of the fire-resistant layer;

[0060] 23a First closed heat insulation disc, 23b First fireproof disc;

[0061] 24a Second closed heat insulation disc, 24b Second fireproof disc, 24c Third fireproof disc;

[0062] 25a Fireproof ring, 25b Closed heat insulation ring, 25c Fourth fireproof disc;

[0063] 26a First layer of shell, 26b Stacked particles;

[0064] 27a Disc part of the fire-resistant layer, 27b Convex part of the fire-resistant layer;

[0065] 3 Heat insulation support structure;

[0066] 31 Heat insulation support unit;

[0067] 32a Body part of the heat insulation support, 32b Protruding part of the heat insulation support;

[0068] 4 Middle flow guide member;

[0069] 41 Flow-through structure, 42 Bending plate, 43 Pressure relief valve disc;

[0070] 5 First annular flow guide member;

[0071] 6 Second annular flow guide member;

[0072] 7 First circumferential partition;

[0073] 8 Second circumferential partition;

[0074] G11 Airflow in the outer area, G12 Airflow in the inner area;

[0075] Airflow in the outer ring area G21, airflow in the inner ring area G22, airflow in the middle area G23;

[0076] Airflow in the outer layer area G31, airflow in the inner area G32, airflow in the inner layer area G321, airflow in the middle area G322 Detailed implementation manners

[0077] The following describes in detail the specific implementation manners of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0078] The following describes the long-time flame arrester structure according to the present invention with reference to the accompanying drawings.

[0079] Through analysis, when the existing pipe end flame arrester or flame arrester breathing valve burns for a long time, the combustion heat has three heat transfer directions. One is to transfer to the inside of the flame arrester through heat conduction and thermal radiation. The second is to be carried away by some combustible gases discharged by the flame arrester. The third is to be dissipated to the outside atmosphere through heat conduction and thermal radiation, etc.

[0080] Both the second and third heat transfer directions mentioned above are beneficial to preventing the combustion heat from accumulating in the flame arrester, making the flame arrest effect of the flame arrester better. The first heat transfer direction is not the case. The transfer of combustion heat to the inside of the flame arrester will increase the risk of flashback and burning through of the flame arrester.

[0081] However, due to the flame arrest structure and the form of the internal structure of the existing pipe end flame arrester or flame arrester breathing valve, when the flame arrest structure burns, the main heat transfer direction of the combustion heat is the first one mentioned above. Therefore, the combustion heat will quickly accumulate in the flame arrest structure and will accumulate in a local area of the flame arrest structure (usually the middle area), and it is easy to have a burning through phenomenon in this local area.

[0082] To solve the deficiencies of the existing technology, the long-time flame arrester structure of the present invention is mainly optimized based on two design directions: one is to enhance the heat transfer in the second and third heat transfer directions as much as possible, that is, to enhance the external dissipation of the combustion heat; the other is to weaken the heat transfer in the first heat transfer direction as much as possible, that is, to weaken the transfer of the combustion heat to the inside of the long-time flame arrester structure.

[0083] Multiple alternative embodiments of the long-time flame arrester structure of the present invention will be provided later. Each embodiment is designed by adopting at least one of the above two design directions, and can effectively extend the flame arrest duration.

[0084] In each alternative embodiment, first refer to Figure 1, the basic structure of the long-time flame arrester structure includes a housing 1 and a fire-resistant structure. Specifically, the housing 1 is provided with a pressure-relief air inlet end 11, a pressure-relief air outlet end 12, and a cavity 13 connecting the pressure-relief air inlet end 11 and the pressure-relief air outlet end 12. When it is necessary to release the gas pressure through the long-time flame arrester structure, the pressure-relief air flow sequentially passes through the pressure-relief air inlet end 11, the cavity 13, and the pressure-relief air outlet end 12 and is discharged. In addition, the fire-resistant structure is arranged at the pressure-relief air outlet end 12. In order to ensure that the pressure-relief air flow can be discharged from the pressure-relief air outlet end 12, structures such as holes and gaps need to be arranged in the fire-resistant structure.

[0085] When there is an ignition source in the outside world and the pressure-relief air flow is ignited on the downstream side of the fire-resistant structure, the following two working conditions exist:

[0086] One is the non-long-time fire-resistant working condition. At this time, the pressure-relief air flow is not continuously discharged through the pressure-relief air outlet end 12. Therefore, under the quenching and outward heat transfer effects of the fire-resistant structure, the fire-resistant structure can prevent the flame from spreading upstream (i.e., inside the long-time flame arrester structure) of the fire-resistant structure;

[0087] The other is the long-time fire-resistant working condition. At this time, the pressure-relief air flow is continuously discharged through the pressure-relief air outlet end 12, and there will be a flame on the downstream side of the fire-resistant structure for a long time. The fire-resistant structure may not be able to prevent the flame from spreading upstream of the fire-resistant structure, and even the flame will burn through the fire-resistant structure. These situations are likely to cause more serious accidents such as storage tank fires or explosions.

[0088] Next, multiple optional embodiments that can effectively extend the flame arrest duration will be introduced one by one:

[0089] Airflow control method 1 (cavity diversion structure)

[0090] Referring to Figure 3 and Figure 11 , the long-time flame arrester structure may include a cavity diversion structure arranged in the cavity 13. Specifically, the cavity diversion structure may include a middle diversion member 4 arranged opposite to the pressure-relief air inlet end 11. Under the diversion action of the middle diversion member 4, the pressure-relief air flow flowing into the cavity 13 from the pressure-relief air inlet end 11 can be divided into an outer region air flow G11 flowing in the outer region of the cavity 13 and an inner region air flow G12 flowing in the inner region of the cavity 13.

[0091] Compared with the existing flame arrester in the long-time combustion working condition where the combustion heat accumulates in a local area (usually the middle area) of the flame arrester structure, resulting in difficult heat dissipation of the combustion heat and even burning through of the flame arrester structure, the long-time flame arrester structure of this embodiment can actively divert the pressure-relief air flow flowing into the cavity 13 by arranging the middle diversion member 4. The divided outer region air flow G11 and inner region air flow G12 can disperse the heat in the fire-resistant structure to different regions, thereby effectively reducing the risk of flashback and burning through phenomena and effectively extending the flame arrest duration.

[0092] Further, with reference to Figure 4 and Figure 12 , the middle flow guide member 4 may be provided with a flow-through structure 41 (such as a plurality of holes or slits) therethrough. At this time, the pressure relief air flow flowing into the cavity 13 from the pressure relief air inlet end 11 will pass through the middle flow guide member 4 through the outer peripheral edge of the middle flow guide member 4 and the flow-through structure 41. The pressure relief air flow passing through the outer peripheral edge of the middle flow guide member 4 will be divided into two air flows. The air flow in the outer region is the outer ring region air flow G21, and a part of the air flow in the inner region will converge with the pressure relief air flow passing through the flow-through structure 41. Thus, the air flow in the inner region is further formed into two split air flows with different flow velocities and / or flow rates, that is, the inner ring region air flow G22 and the middle region air flow G23.

[0093] In other words, overall, after the pressure relief air flow passes through the middle flow guide member 4 provided with the flow-through structure 41, in the region of the cavity 13 downstream of the middle flow guide member 4, there will be an outer ring region air flow G21, an inner ring region air flow G22, and a middle region air flow G23 that are distributed from outside to inside in sequence. This flow field form can disperse the heat in the fire-resistant structure to more different regions, further prolonging the fire resistance time.

[0094] With reference to Figure 4 , to reduce the resistance of the pressure relief air flow, the middle flow guide member 4 may be set as a curved plate 42 (such as an arc-shaped plate), and the convex surface of the curved plate 42 faces the pressure relief air inlet end 11. In this way, when the pressure relief air flow is divided at the outer peripheral edge of the middle flow guide member 4, the air flow resistance is smaller, ensuring that the long-time fire-resistant structure has a higher pressure relief speed, and at the same time is conducive to taking away the heat in the cavity 13 more quickly.

[0095] In addition to being set as the curved plate 42, the middle flow guide member 4 may also be set into other streamlined shapes, such as conical, spindle-shaped, water droplet-shaped, etc., and the present invention does not limit this.

[0096] With reference to Figure 6 and Figure 7 , when the long-time fire-resistant structure is applied to a breathing valve (or an exhalation valve), the middle flow guide member 4 may be used as the pressure relief valve disc 43 of the breathing valve (or the exhalation valve) to switch the on-off state between the cavity 13 and the pressure relief air inlet end 11. When the pressure relief valve disc 43 moves downward and opens to connect the cavity 13 with the pressure relief air inlet end 11, the pressure relief valve disc 43 plays the above-mentioned guiding and splitting roles.

[0097] With reference to Figure 5 , the flow-through structure 41 may include a plurality of flow-through holes formed in the middle circular region of the middle flow guide member 4. In addition to roughly limiting the flow range of the middle region air flow G23 to the middle cylindrical region of the cavity 13, the flow velocity and flow rate of the middle region air flow G23 can also be adjusted by designing different aperture sizes and hole distribution densities, etc.

[0098] In a specific embodiment, the total flow-through area of the over-current structure 41 is not greater than one-third of the flow-through area of the pressure-relief air inlet end 11, so as to prevent the flow rate of the air flow G23 in the middle region from being too large and causing the problem that the middle region of the burn-resistant structure overheats and cannot be effectively solved.

[0099] In a specific embodiment, the area of the axial projection of the middle flow guide member 4 is not greater than the area of the axial projection of the pressure-relief air inlet end 11, so as to prevent the radial dimension of the middle flow guide member 4 from being too large and affecting the discharge speed of the pressure-relief air flow.

[0100] In a specific embodiment, referring to Figure 13 , the diameter of the middle flow guide member 4 is D1, the distance between the middle flow guide member 4 and the inner wall of the upstream end of the cavity 13 is H1, the distance between the middle flow guide member 4 and the inner wall of the downstream end of the cavity 13 is H2, the inner diameter of the cavity 13 is D, and the inner diameter of the pressure-relief air inlet end 11 is d, satisfying:

[0101] Wherein, e is the natural constant, and its value is approximately 2.718.

[0102] The above relational expressions mainly preferably limit the size and position of the middle flow guide member 4. Generally, in order to obtain better flow performance, the inner diameter D of the cavity 13 is more than twice the inner diameter d of the pressure-relief air inlet end 11. However, in the case where the middle flow guide member 4 is not provided, after the pressure-relief air flow enters the cavity 13 from the pressure-relief air inlet end 11, the flow velocity in the middle region of the cavity will be higher than that in the outer ring region of the cavity, resulting in the pressure-relief air flow concentrating on passing through the middle region of the burn-resistant structure and having a large pressure drop.

[0103] From the perspective of optimizing the flow field distribution, the above relational expressions design the specific range of the diameter D1 of the middle flow guide member 4, and respectively limit the ranges of the distance H1 between the middle flow guide member 4 and the inner wall of the upstream end of the cavity 13 and the distance H2 between the middle flow guide member 4 and the inner wall of the downstream end of the cavity 13.

[0104] Specifically, the diameter D1 mainly considers that the main air flow of the pressure-relief air flow impacts on the middle flow guide member 4 and then flows to the downstream from the outer peripheral edge of the middle flow guide member 4. If the diameter D1 is too large, the flow-through space of the outer side air flow will be reduced. Therefore, according to the experimental data and the basic principles of fluid mechanics, the above range limit is imposed on the diameter D1.

[0105] The distance H1 mainly considers that the flow-through area required for the pressure-relief air flow to pass through here should be larger than the oncoming flow area of the pressure-relief air inlet end 11 to reduce the pressure loss caused by the 90° bend.

[0106] The spacing H2 is considered to ensure that the oncoming flow can fully develop after passing through the middle flow guide member 4, so that the refracted flow generated by the airflow hitting the inner wall of the downstream end of the cavity 13 can have a good disturbing effect on the airflow, thereby forming a relatively uniform flow velocity distribution. It is mainly derived from fluid mechanics theory, numerical simulation and experimental results.

[0107] Referring to Figure 8 、 Figure 9 and Figure 12 , the cavity flow guide structure may further include a first annular flow guide member 5 provided on the downstream side of the middle flow guide member 4. Wherein, the outer circumferential wall of the first annular flow guide member 5 is spaced from the inner circumferential wall of the cavity 13. When the middle flow guide member 4 has already divided the outer region airflow G11 and the inner region airflow G12, the outer region airflow G11 and the inner region airflow G12 can be further divided by the first annular flow guide member 5 when passing through it. At this time, the airflow on the outer part of the outer region airflow G11 flows downstream through the spaced area between the outer circumferential wall of the first annular flow guide member 5 and the inner circumferential wall of the cavity 13, and this part of the airflow is the outer ring region airflow G21; while the airflow on the inner part of the outer region airflow G11 and the airflow on the outer part of the inner region airflow G12 are divided when passing through the inner circumferential edge of the first annular flow guide member 5. The divided airflow close to the inner circumferential edge of the first annular flow guide member 5 is the inner ring region airflow G22, and the divided airflow far from the inner circumferential edge of the first annular flow guide member 5 (i.e., the divided airflow flowing in the middle region of the cavity 13) is the middle region airflow G23.

[0108] In other words, overall, after the pressure relief airflow is divided by the middle flow guide member 4 and the first annular flow guide member 5, there will be an outer ring region airflow G21, an inner ring region airflow G22 and a middle region airflow G23 distributed in sequence from outside to inside in the region of the cavity 13 downstream of the first annular flow guide member 5. This flow field form can disperse the heat in the fire-resistant structure to more different regions, further prolonging the fire resistance duration.

[0109] It should be noted that when the middle flow guide member 4 is provided with a flow-through structure 41 and the cavity flow guide structure is provided with a first annular flow guide member 5 at the same time, there will also be an outer ring region airflow G21, an inner ring region airflow G22 and a middle region airflow G23 distributed in sequence from outside to inside in the region of the cavity 13 downstream of the first annular flow guide member 5, because the flow-through structure 41 mainly affects the flow rate and / or flow velocity of the middle region airflow G23.

[0110] Referring to Figure 10, the cavity flow guiding structure may further include a second annular flow guiding member 6 disposed on the downstream side of the first annular flow guiding member 5. Among them, the outer circumferential wall of the second annular flow guiding member 6 is spaced from the inner circumferential wall of the cavity 13, and the outer ring radius of the second annular flow guiding member 6 is greater than the outer ring radius of the first annular flow guiding member 5. Obviously, the second annular flow guiding member 6 can further guide and shunt the flow field forms of the outer ring region air flow G21, the inner ring region air flow G22, and the middle region air flow G23 to adjust the flow rate and / or flow velocity of the air flow in each region, or can further divide more strands of regional air flows, and disperse the heat in the fire-resistant structure as evenly as possible to achieve an excellent effect of extending the fire resistance duration.

[0111] The present invention only lists some optional forms of the cavity flow guiding structure for illustration. It can be understood that other cavity flow guiding structure forms that can also divide the pressure relief air flow in the cavity 13 into multiple strands of regional air flows should also fall within the scope of the concept of the present invention.

[0112] Airflow control method 2 (inlet end diversion structure)

[0113] Referring to Figure 14 and Figure 15 , the long-time fire-resistant structure may include an intake end flow guiding structure disposed in the pressure relief intake end 11. Specifically, the intake end flow guiding structure may include a first circumferential partition 7, and the outer circumferential wall of the first circumferential partition 7 is spaced from the inner circumferential wall of the pressure relief intake end 11. Thus, the pressure relief air flow flowing into the pressure relief intake end 11 can be divided into an outer layer region air flow G31 flowing between the inner circumferential wall of the pressure relief intake end 11 and the outer circumferential wall of the first circumferential partition 7 and an inner region air flow G32 flowing inside the first circumferential partition 7 under the guiding action of the first circumferential partition 7.

[0114] Compared with the existing fire arrester under the long-time combustion condition where the combustion heat accumulates in a local area (usually the middle area) of the fire-resistant structure, resulting in difficult heat dissipation of the combustion heat and even burning through the fire-resistant structure, the long-time fire-resistant structure of this embodiment can actively shunt the pressure relief air flow flowing into the pressure relief intake end 11 by setting the first circumferential partition 7. The shunted outer layer region air flow G31 and inner region air flow G32 can disperse the heat in the fire-resistant structure to different regions, thereby effectively reducing the risk of flashback and burning through, effectively extending the fire resistance duration, and achieving long-time fire resistance.

[0115] Further, referring to Figure 14 and Figure 16, the intake-end flow guiding structure may further include a second circumferential partition 8 disposed within the first circumferential partition 7, and the second circumferential partition 8 is spaced apart from the first circumferential partition 7 both inside and outside. At this time, under the guiding action of the second circumferential partition 8, the internal region airflow G32 can be further divided into an inner-layer region airflow G321 flowing between the first circumferential partition 7 and the second circumferential partition 8 and an intermediate region airflow G322 flowing inside the second circumferential partition 8.

[0116] In other words, overall, when the pressure-relief airflow passes through the intake-end flow guiding structure provided with the first circumferential partition 7 and the second circumferential partition 8, there will be an outer-layer region airflow G31, an inner-layer region airflow G321, and an intermediate region airflow G322 that are sequentially distributed from outside to inside within the pressure-relief intake end 11. This flow field form can disperse the heat in the fire-resistant structure to more different regions, further prolonging the fire-blocking duration.

[0117] In a specific embodiment, the structural parameter relationship between the fire-resistant structure and the intake-end flow guiding structure is defined. Specifically, the fire-resistant structure may include an outer-layer flow-through structure, an inner-layer flow-through structure, and an intermediate flow-through structure for the outer-layer region airflow G31, the inner-layer region airflow G321, and the intermediate region airflow G322 to flow through respectively; the porosity of the outer-layer flow-through structure, the inner-layer flow-through structure, and the intermediate flow-through structure are σ1, σ2, and σ3 respectively; the flow-through areas of the outer-layer flow-through structure, the inner-layer flow-through structure, and the intermediate flow-through structure are S1, S2, and S3 respectively.

[0118] In addition, the inlet-end diversion ratios of the annular region between the inner peripheral wall of the pressure-relief intake end 11 and the outer peripheral wall of the first circumferential partition 7, the annular region between the first circumferential partition 7 and the second circumferential partition 8, and the inner region of the second circumferential partition 8 are a, b, and c respectively.

[0119] Furthermore, the total flow-through area of the inlet end of the intake-end flow guiding structure is S0.

[0120] Based on the principle of flow conservation, the following relationships are set such that the flow rate of the pressure-relief airflow flowing into the annular region between the inner peripheral wall of the pressure-relief intake end 11 and the outer peripheral wall of the first circumferential partition 7 is equal to the flow rate of the pressure-relief airflow flowing through the outer-layer flow-through structure of the fire-resistant structure, the flow rate of the pressure-relief airflow flowing into the annular region between the first circumferential partition 7 and the second circumferential partition 8 is equal to the flow rate of the pressure-relief airflow flowing through the inner-layer flow-through structure of the fire-resistant structure, and the flow rate of the pressure-relief airflow flowing into the inner region of the second circumferential partition 8 is equal to the flow rate of the pressure-relief airflow flowing through the intermediate flow-through structure of the fire-resistant structure. The specific relationships are as follows:

[0121] (S1*σ1) / (S0*a) ≤ 2 / 3;

[0122] (S2*σ2) / (S0*b) ≥ 5;

[0123] 1 ≤ (S3 * σ3) / (S0 * c) ≤ 3.

[0124] It should be noted that the air inlet end flow guiding structure may also be provided with more circumferential partitions in addition to the first circumferential partition 7 and the second circumferential partition 8 to divide more regional airflows and disperse the heat in the fire-resistant structure as evenly as possible to achieve an excellent effect of extending the fire resistance duration.

[0125] Only some optional forms of the air inlet end flow guiding structure are listed in the present invention for illustration. It can be understood that other forms of air inlet end flow guiding structures that can also divide the pressure relief airflows in the pressure relief air inlet end 11 into multiple regional airflows should also fall within the scope of the concept of the present invention.

[0126] In addition, in addition to the cavity flow guiding structure and the air inlet end flow guiding structure provided above, other forms of flow guiding structures may also be provided in the housing 1. For example, an integral housing flow guiding structure that simultaneously occupies the spaces of the cavity 13 and the pressure relief air inlet end 11 can also be designed. In other words, the present invention does not limit the specific form of the flow guiding structure provided in the housing 1. As long as the flow guiding structure is located upstream of the fire-resistant structure and can divide the pressure relief airflows in the housing 1 into multiple regional airflows flowing towards different regions of the fire-resistant structure, the effect of extending the fire resistance duration can be achieved.

[0127] Airflow control method 3 (porosity distribution of refractory structure)

[0128] By providing multiple fire-resistant layer partitions with different porosities in the fire-resistant structure, the pressure relief airflows can have different flow velocities and / or flow rates when passing through the multiple fire-resistant layer partitions. For example, for the regions in the fire-resistant structure that are prone to local overheating during combustion, the porosity of this region can be relatively small to reduce the flow rate passing through this region, thereby reducing the combustion heat in this region.

[0129] Compared with the existing fire arrester under long-time combustion conditions where the combustion heat accumulates in the local region (usually the middle region) of the fire resistance structure, resulting in difficult heat dissipation of the combustion heat and even burning through the fire resistance structure, the long-time fire resistance structure of this embodiment can actively shunt the pressure relief airflows flowing through the fire-resistant structure by reasonably setting the porosities of multiple fire-resistant layer partitions, prevent local overheating of the fire-resistant structure, thereby effectively reducing the risk of flashback and burning through, effectively extending the fire resistance duration, and achieving long-time fire resistance.

[0130] Refer to Figure 22 , the fire-resistant layer partition may include a fire-resistant layer outer ring region 22a and a fire-resistant layer inner region located inside the fire-resistant layer outer ring region 22a. In this way, when the pressure relief airflows pass through the fire-resistant structure, they will be divided into two regional airflows, and the two regional airflows are discharged through the fire-resistant layer outer ring region 22a and the fire-resistant layer inner region respectively.

[0131] Further, referring to Figure 24 , the inner region of the fire-resistant layer may include an inner ring region 22b and an intermediate region 22c of the fire-resistant layer. At this time, the outer ring region 22a, the inner ring region 22b, and the intermediate region 22c of the fire-resistant layer are arranged in sequence from outside to inside. In this way, when the pressure relief air flow passes through the fire-resistant structure, it will be divided into three regional air flows, and the three regional air flows are discharged through the outer ring region 22a, the inner ring region 22b, and the intermediate region 22c of the fire-resistant layer respectively.

[0132] In a specific embodiment, the radius of the intermediate region 22c of the fire-resistant layer is r1, the outer ring radius of the inner ring region 22b of the fire-resistant layer is r2, and the outer ring radius of the outer ring region 22a of the fire-resistant layer is R, satisfying: 0 ≤ r1 ≤ R / 3, R / 3 ≤ r2 ≤ 2R / 3. In particular, when r1 = 0, it is equivalent to that the fire-resistant layer partition includes the outer ring region 22a and the inner region of the fire-resistant layer, and the inner region of the fire-resistant layer is not further divided into the inner ring region 22b and the intermediate region 22c of the fire-resistant layer.

[0133] It should be noted that more annular fire-resistant layer partitions can be divided in the fire-resistant structure to divide more regional air flows, and the heat in the fire-resistant structure can be dispersed as evenly as possible to achieve an excellent effect of extending the fire resistance duration.

[0134] The specific structural forms of the outer ring region 22a, the inner region of the fire-resistant layer, the inner ring region 22b, and the intermediate region 22c of the fire-resistant layer can refer to the embodiments of the radial heat insulation of the fire-resistant structure in the following text, and will not be described in detail here. It can be understood that other structural forms of the fire-resistant layer partitions that can also divide the pressure relief air flow into multiple regional air flows should also fall within the scope of the concept of the present invention.

[0135] Flow velocity and flow rate distribution form under airflow control

[0136] It has been proved by the experiments of the designers of the present invention that when the fire-resistant structure burns, the faster the flow rate of the pressure relief air flow passing through the fire-resistant structure, the smaller the combustion heat transferred to the inside of the long-time fire-resistant structure. Analyzing from the theoretical level, mainly because the air flow with a high flow rate can take away the combustion heat accumulated in the fire-resistant structure faster and accelerate the outward dissipation of the combustion heat.

[0137] Therefore, when dividing the pressure relief air flow into multiple regional air flows through the active shunt technology (i.e., the aforementioned air flow control methods one, two, and three), the structural and parameter adjustments can be made to the cavity diversion structure, the intake end diversion structure, or the porosity distribution form of the fire-resistant structure, so that the flow rate and flow distribution form of each regional air flow meet the requirements of extending the fire resistance duration.

[0138] Now, two optional flow rate and flow distribution forms with better effects of extending the fire resistance duration are provided:

[0139] The first distribution form is as follows: the air flow in the high-flow-rate and large-flow-region passes through the outer region of the fire-resistant structure, and the air flow in the low-flow-rate and low-flow-region passes through the inner region of the fire-resistant structure. In particular, there may be no air flow passing through the inner region of the fire-resistant structure.

[0140] When the fire-resistant structure burns, the large-flow air flow will pass through the outer region of the fire-resistant structure, where the heat dissipation efficiency is relatively high, at a high speed, taking away a large amount of combustion heat faster and further increasing the heat dissipation rate of the combustion heat. The low-flow air flow will pass through the inner region (including the middle region) of the fire-resistant structure at a low speed, or there may be no air flow passing through the inner region of the fire-resistant structure. Compared with the existing flame arrester in which the pressure-relief air flow passes through the middle region of the fire-resistant structure in a large flow, it can effectively solve the problem of local heat concentration in the middle region of the fire-resistant structure and effectively reduce the risk of flashback and burning through of the middle region.

[0141] The second distribution form is as follows: the air flow in the high-flow-rate and large-flow-region passes through the outer ring region of the fire-resistant structure, the air flow in the low-flow-rate and low-flow-region passes through the inner ring region of the fire-resistant structure, and the air flow in the medium-flow-rate and medium-flow-region passes through the middle region of the fire-resistant structure. In particular, there may be no air flow passing through the inner ring region of the fire-resistant structure.

[0142] When the fire-resistant structure burns, the large-flow air flow will pass through the outer ring region of the fire-resistant structure, where the heat dissipation efficiency is relatively high, at a high speed, taking away a large amount of combustion heat faster and further increasing the heat dissipation rate of the combustion heat. The medium-flow air flow will pass through the middle region of the fire-resistant structure at a medium speed. Compared with the existing flame arrester in which the pressure-relief air flow passes through the middle region of the fire-resistant structure in a large flow, it can effectively solve the problem of local heat concentration in the middle region of the fire-resistant structure and effectively reduce the risk of flashback and burning through of the middle region. In addition, the low-flow air flow will pass through the inner ring region of the fire-resistant structure at a low speed, or there may be no air flow passing through the inner ring region of the fire-resistant structure, which is equivalent to forming a low-thermal-conductivity region between the outer ring region and the middle region of the fire-resistant structure, thereby weakening the transfer of combustion heat from the outer ring region to the middle region of the fire-resistant structure and further reducing the risk of flashback and burning through of the middle region of the fire-resistant structure.

[0143] In a specific embodiment, the average velocity of the air flow in the high-flow-rate and large-flow-region is defined as v1 and the flow area is defined as s1, the average velocity of the air flow in the low-flow-rate and low-flow-region is defined as v2 and the flow area is defined as s2, the average velocity of the air flow in the medium-flow-rate and medium-flow-region is defined as v3 and the flow area is defined as s3, and the average velocity of the pressure-relief air flow flowing into the pressure-relief air inlet 11 is defined as v and the flow area is defined as s.

[0144] At this time, the porosity distribution form of the cavity flow guiding structure, the air inlet end flow guiding structure or the fire-resistant structure can be adjusted in terms of structure and parameters to meet the following relational expressions:

[0145] v1≥1.2v, preferably v1≥1.5v;

[0146] v3≤0.8v, preferably v3≤0.5v;

[0147] v2≤0.4v, preferably v2≤0.2v;

[0148] v1*s1≥0.5v*s, preferably v1*s1≥0.7v*s;

[0149] v3*s3≤0.5v*s, preferably v3*s3≤0.3v*s;

[0150] v2*s2≤0.3v*s, preferably v2*s2≤0.1v*s.

[0151] For the cavity flow guiding structure (air flow control method 1):

[0152] Refer to Figure 11 , when the cavity flow guiding structure divides the outer region air flow G11 and the inner region air flow G12 in the cavity 13, the flow velocity of the outer region air flow G11 can be made greater than that of the inner region air flow G12, and / or the flow rate of the outer region air flow G11 can be made greater than that of the inner region air flow G12 to meet the aforementioned first flow velocity and flow rate distribution form.

[0153] Refer to Figure 12 , when the cavity flow guiding structure divides the outer ring region air flow G21, the inner ring region air flow G22, and the middle region air flow G23 in the cavity 13, the flow velocities of the outer ring region air flow G21, the middle region air flow G23, and the inner ring region air flow G22 can be distributed from large to small, and / or the flow rates of the outer ring region air flow G21, the middle region air flow G23, and the inner ring region air flow G22 can be distributed from large to small to meet the aforementioned second flow velocity and flow rate distribution form.

[0154] It should be noted that a series of parameters such as the radii of the middle flow guiding member 4, the first annular flow guiding member 5, and the second annular flow guiding member 6 of the cavity flow guiding structure, the spacing in the upstream and downstream directions, and the spacing from the inner peripheral wall of the cavity 13 can be adjusted to meet the actually required flow velocity and flow rate distribution form.

[0155] For the air inlet end flow guiding structure (air flow control method 2):

[0156] Refer to Figure 15, when the intake end flow guiding structure divides the outer region airflow G31 and the inner region airflow G32 in the pressure relief intake end 11, the flow velocity of the outer region airflow G31 can be made greater than that of the inner region airflow G32, and / or the flow rate of the outer region airflow G31 can be made greater than that of the inner region airflow G32, so as to meet the aforementioned first flow velocity and flow rate distribution form;

[0157] For example, the inlet end flow area of the annular region between the inner peripheral wall of the pressure relief intake end 11 and the first circumferential partition 7 can be made greater than the inlet end flow area of the inner region of the first circumferential partition 7, so as to achieve that the flow rate of the outer region airflow G31 is greater than that of the inner region airflow G32;

[0158] In addition, the outlet end flow area of the annular region between the inner peripheral wall of the pressure relief intake end 11 and the first circumferential partition 7 can be made smaller than the outlet end flow area of the inner region of the first circumferential partition 7, so as to achieve that the flow velocity of the outer region airflow G31 is greater than that of the inner region airflow G32.

[0159] Refer to Figure 16 , when the intake end flow guiding structure divides the outer region airflow G31, the inner layer region airflow G321, and the middle region airflow G322 in the pressure relief intake end 11, the flow velocities of the outer region airflow G31, the middle region airflow G322, and the inner layer region airflow G321 can be distributed from large to small, and / or the flow rates of the outer region airflow G31, the middle region airflow G322, and the inner layer region airflow G321 can be distributed from large to small, so as to meet the aforementioned second flow velocity and flow rate distribution form;

[0160] For example, the inlet end flow splitting ratio of the annular region between the inner peripheral wall of the pressure relief intake end 11 and the first circumferential partition 7 can be a, the inlet end flow splitting ratio of the annular region between the first circumferential partition 7 and the second circumferential partition 8 can be b, and the inlet end flow splitting ratio of the inner region of the second circumferential partition 8 can be c, satisfying: a > c > b, so as to achieve that the flow rates of the outer region airflow G31, the middle region airflow G322, and the inner layer region airflow G321 are distributed from large to small;

[0161] In addition, the outlet end flow areas of the annular region between the inner peripheral wall of the pressure relief intake end 11 and the first circumferential partition 7, the outlet end flow area of the inner region of the second circumferential partition 8, and the outlet end flow area of the annular region between the first circumferential partition 7 and the second circumferential partition 8 can be set from small to large, so as to achieve that the flow velocities of the outer region airflow G31, the middle region airflow G322, and the inner layer region airflow G321 are distributed from large to small.

[0162] For the porosity distribution of the fire-resistant structure (airflow control method three):

[0163] Refer toFigure 22 When the fire-resistant structure is provided with a fire-resistant layer outer ring area 22a and a fire-resistant layer inner area located inside the fire-resistant layer outer ring area 22a, the porosity of the fire-resistant layer outer ring area 22a can be made greater than the porosity of the fire-resistant layer inner area to meet the aforementioned first flow velocity and flow rate distribution form.

[0164] Refer to Figure 24 When the fire-resistant structure is provided with a fire-resistant layer outer ring area 22a, a fire-resistant layer inner ring area 22b, and a fire-resistant layer middle area 22c arranged in sequence from outside to inside, the porosity of the fire-resistant layer outer ring area 22a, the porosity of the fire-resistant layer middle area 22c, and the porosity of the fire-resistant layer inner ring area 22b can be set from large to small to meet the aforementioned second flow velocity and flow rate distribution form.

[0165] The porosity mainly needs to meet the requirements of fire resistance while taking into account the requirements of flow performance, and at the same time, it can achieve the requirement of changing the flow field distribution by changing the porosity design. For the fire resistance requirement, for different combustible gases, the porosity requirements are different. According to the experimental results of the representative gases in the following table:

[0166]

[0167] The relationship between the porosity and the ring diameters of the fire-resistant layer outer ring area 22a, the fire-resistant layer inner ring area 22b, and the fire-resistant layer middle area 22c can be constructed, which is related to the gas type, and the following relational expressions are fitted:

[0168]

[0169]

[0170] Among them, ε max is the set of upper limit values of porosity, ε min is the set of lower limit values of porosity, the radius of the fire-resistant layer middle area 22c is r1, the outer ring radius of the fire-resistant layer inner ring area 22b is r2, the outer ring radius of the fire-resistant layer outer ring area 22a is R, MESG is the maximum experimental safe gap, MESG (maximum experimental safe gap), for all concentrations of the measured gas or vapor, when the internal mixture is ignited, the maximum gap between two parts of an internal cavity that prevents the external gas mixture from being ignited through a 25-mm long flame path, and the safe gap is measured according to IEC60079-20-1:2010.

[0171] And it should be noted that the porosity of the fire-resistant layer middle area 22c should be lower than the minimum porosity of the fire-resistant layer outer ring area 22a.

[0172] Multi-layer refractory structure

[0173] Refer to Figure 1 andFigure 2 The fire-resistant structure may include a plurality of fire-resistant layers 2 arranged at intervals along the axial direction of the pressure relief exhaust end 12. Among them, the fire-resistant layer 2 located at the most downstream is formed as a combustion-side fire-resistant layer 21a, and the fire-resistant layer 2 located upstream of the combustion-side fire-resistant layer 21a is formed as a protection-side fire-resistant layer 21b.

[0174] When the combustible pressure relief gas flow continuously discharges through the pressure relief exhaust end 12 and is ignited on the downstream side of the combustion-side fire-resistant layer 21a, the combustion-side fire-resistant layer 21a will be burned for a long time. At this time, since there is at least one protection-side fire-resistant layer 21b upstream of the combustion-side fire-resistant layer 21a, the heat dissipation area of the combustion heat can be greatly increased, effectively reducing the risk that the combustion-side fire-resistant layer 21a is burned through due to heat accumulation. And even if the combustion-side fire-resistant layer 21a is burned through, the protection-side fire-resistant layer 21b can also take over the role of fire blocking, thereby greatly extending the fire blocking duration of the fire-resistant structure.

[0175] The following provides some embodiments of the fire-resistant structure parameters that have been experimentally proven and can obtain better fire blocking duration extension effects:

[0176] In a specific embodiment, the protection-side fire-resistant layer 21b closest to the combustion-side fire-resistant layer 21a is defined as the first protection-side fire-resistant layer. The distance between the combustion-side fire-resistant layer 21a and the first protection-side fire-resistant layer is L, and the diameter of the first protection-side fire-resistant layer is D2, satisfying: L = 3.31 + 2.615MESG - 0.012D 2 , where MESG is the maximum experimental safe gap, MESG (maximum experimental safe gap). For all concentrations of the measured gas or vapor, when the internal mixture is ignited, it is the maximum gap between two parts of an internal cavity with a 25-mm long flame path to prevent the external gas mixture from being ignited. The safe gap is measured according to IEC60079-20-1:2010.

[0177] It can be seen from the above relationship that L is related to D 2 and the fire blocking grade (the fire blocking grade is represented by the MESG value of the representative gas).

[0178] It should be noted that the spacing L has a great influence on the fire resistance and burning resistance performance. When the spacing L is small, since the heat transfer of the burning-side fire-resistant layer 21a is mainly heat conduction and thermal radiation, it will cause the heat transfer to increase geometrically, especially thermal radiation, which is inversely proportional to the square of the spacing L. The increase in heat will cause the temperature of the first protection-side fire-resistant layer to rise rapidly, increasing the risk of fire resistance failure; when the spacing L is large, after the burning-side fire-resistant layer 21a burns for a long time, the temperature on its upstream side is relatively high, and it is easy to ignite the combustible gas in the gap between the burning-side fire-resistant layer 21a and the first protection-side fire-resistant layer. The combustible gas continues to burn in the large gap, which is likely to cause a smoldering phenomenon, and the combustion heat in the gap is more difficult to dissipate outward, and most of it is transferred upstream, which also increases the risk of fire resistance failure.

[0179] Therefore, in order to obtain a better fire resistance effect, preferably, the size of the spacing L is limited by the above relational formula. The above relational formula is related to the type of gas and is obtained by fitting the experimental results in the following table:

[0180]

[0181] In a specific embodiment, when the long-term fire resistance structure is actually applied, to obtain a better effect of extending the fire resistance duration, it is necessary to satisfy:

[0182] For Class IIA combustible gases, L ≤ 6 mm, preferably, 2 mm ≤ L ≤ 4 mm;

[0183] For Class IIB3 combustible gases, L ≤ 4 mm, preferably, 1 mm ≤ L ≤ 2 mm.

[0184] By limiting L, it is possible to prevent the value of L from being too large, reducing the risk of interlayer smoldering caused by the high-temperature fire-resistant layer directly igniting the pressure relief airflow in the interval area between the burning-side fire-resistant layer 21a and the first protection-side fire-resistant layer, thereby reducing the risk of fire resistance failure. In addition, it is possible to prevent the value of L from being too small, thereby preventing the enhancement of heat conduction between the burning-side fire-resistant layer 21a and the first protection-side fire-resistant layer.

[0185] In a specific embodiment, the total thickness of the multiple fire-resistant layers 2 is T, and the porosity of the fire-resistant layer 2 is δ, satisfying: T ≥ 3.14e 4.58δ .

[0186] In a specific embodiment, in order to reduce the flow resistance, it is necessary to satisfy: T < 6.28e 4.58δ .

[0187] In a specific embodiment, the thickness of the protection-side fire-resistant layer 21b is T2, satisfying: T2 ≤ 1.57e 4.58δ .

[0188] In a specific embodiment, in order to obtain a better effect of extending the fire resistance duration and a smaller flow resistance, it is satisfied that 0.4 ≤ δ ≤ 0.6.

[0189] In a specific embodiment, the thickness of the burn-resistant layer 21a on the combustion side is T1, and it is satisfied that T1 ≥ T2.

[0190] In a specific embodiment, when the long-time fire-blocking structure is actually applied, in order to obtain a better effect of extending the fire resistance duration and a smaller flow resistance, it is satisfied that T ≥ 30 mm.

[0191] In a specific embodiment, the gap value of the burn-resistant layer 21a on the combustion side is h1, and the gap value of the burn-resistant layer 21b on the protection side is h2, and it is satisfied that h1 ≤ h2.

[0192] In a specific embodiment, h1 ≤ MESG, and preferably, h1 ≤ 0.5 MESG.

[0193] In a specific embodiment, h2 ≤ MESG, and preferably, h2 ≤ 0.8 MESG.

[0194] In a specific embodiment, the gap of the burn-resistant layer 21a on the combustion side is axially deflected relative to the burn-resistant layer 21a on the combustion side, and the deflection angle is α, and it is satisfied that T1 * tanα ≥ h1.

[0195] In a specific embodiment, the flow area of each burn-resistant layer 2 is not less than the flow area of the pressure relief air inlet end 11.

[0196] Axial heat insulation of refractory structure (heat insulation support structure)

[0197] Referring to Figure 1 and Figure 2 , the long-time fire-blocking structure may include a heat insulation support structure 3 provided between two adjacent burn-resistant layers 2, and the heat insulation support structure 3 is in contact with the two adjacent burn-resistant layers 2.

[0198] The heat insulation support structure 3 has a heat insulation function and can effectively weaken the heat radiation and heat conduction between its two adjacent burn-resistant layers 2, so as to reduce and delay the transfer of combustion heat to the inside of the housing 1; at the same time, the heat insulation support structure 3 also has a support function. When the downstream burn-resistant layer 2 is deformed by heat, it can support the deformed burn-resistant layer 2 to avoid its too-fast direct contact with the upstream burn-resistant layer 2, thereby also slowing down the transfer of combustion heat to the inside of the housing 1 and taking into account the overall structural integrity of the burn-resistant structure.

[0199] To improve the support strength, the heat insulation support structure 3 may be arranged to form a support within the entire radial range of the burn-resistant layer 2, so as to effectively prevent the downstream burn-resistant layer 2 from deforming and collapsing after a long-time combustion. For example, referring to Figure 18, a triangular heat insulation support structure 3 can be adopted, and the diameter of the circumcircle of the triangle can be set to be equal to the diameter of the fire-resistant layer 2; or, referring to Figure 17 , a cross-shaped heat insulation support structure 3 can be adopted, and the lengths of the two straight line segments forming the cross can be set to be equal to the diameter of the fire-resistant layer 2.

[0200] To improve the heat insulation effect, the total contact area between the heat insulation support structure 3 and the adjacent two fire-resistant layers 2 should be as small as possible. If the ratio of the total contact area between the heat insulation support structure 3 and the adjacent two fire-resistant layers 2 to the cross-sectional area of the fire-resistant layer 2 is defined as Define the thermal conductivity of the heat insulation support structure 3 as λ, then it satisfies: In other words, is related to λ.

[0201] In a specific embodiment, is not greater than 3%, preferably, is not greater than 1%.

[0202] In a specific embodiment, the heat insulation support structure 3 forms a point contact with the fire-resistant layer 2. For example, the heat insulation support structure 3 can be in contact with the fire-resistant layer 2 by being provided with a bump structure.

[0203] In a specific embodiment, the heat insulation support structure 3 forms a line contact with the fire-resistant layer 2. For example, a slender cylindrical heat insulation support structure 3 can be adopted.

[0204] In a specific embodiment, the heat insulation support structure 3 forms a surface contact with the fire-resistant layer 2. For example, a slender rectangular heat insulation support structure 3 can be adopted.

[0205] To improve the heat insulation effect, it can also be achieved by increasing the thickness of the heat insulation support structure 3.

[0206] In a specific embodiment, the heat insulation support structure 3 is a multi-layer heat insulation support structure. For example, referring to Figure 19 and Figure 20 , the multi-layer heat insulation support structure can include a plurality of heat insulation support units 31 stacked in sequence along the axial direction, that is, the total thickness of the heat insulation support structure 3 is increased by stacking a plurality of independent heat insulation support units 31; or, referring to Figure 21 , the multi-layer heat insulation support structure can also include a heat insulation support body portion 32a and a heat insulation support protruding portion 32b protruding from the heat insulation support body portion 32a along the axial direction, that is, the total thickness of the heat insulation support structure 3 is increased by providing a height increasing structure (heat insulation support protruding portion 32b) in the integral heat insulation support structure 3.

[0207] In addition, the heat-insulating support structure 3 should be made of high-temperature resistant materials to ensure that when the fire-resistant structure burns for a long time and continuously transfers heat to the heat-insulating support structure 3, the heat-insulating support structure 3 will not deform or deform excessively and lose its good support strength.

[0208] In a specific embodiment, the heat-resistant temperature of the heat-insulating support structure 3 is not less than 1000 °C.

[0209] In a specific embodiment, the linear change rate of the heat-insulating support structure 3 is not more than 10%, preferably, the linear change rate of the heat-insulating support structure 3 is not more than 5%, so that the heat-insulating support structure 3 can have no obvious deformation when heated for a long time.

[0210] Furthermore, the present invention does not limit the internal structure of the heat-insulating support structure 3. For example, the heat-insulating support structure 3 can be a solid heat-insulating support structure, a porous heat-insulating support structure with a porous structure, and a hollow heat-insulating support structure with a hollow cavity, etc.

[0211] Radial heat insulation of refractory structure

[0212] Based on the content in the embodiment of the foregoing air flow control method three, obviously, when the fire-resistant structure is provided with one or more fire-resistant layers 2, a single fire-resistant layer 2 can refer to Figure 22 , divide the outer ring area 22a of the fire-resistant layer and the inner area of the fire-resistant layer located inside the outer ring area 22a of the fire-resistant layer; or, a single fire-resistant layer 2 can refer to Figure 24 , divide the outer ring area 22a of the fire-resistant layer, the inner ring area 22b of the fire-resistant layer, and the middle area 22c of the fire-resistant layer arranged in sequence from outside to inside.

[0213] Refer to Figure 22 , when the fire-resistant layer 2 is provided with the outer ring area 22a of the fire-resistant layer and the inner area of the fire-resistant layer, the porosity of the inner area of the fire-resistant layer can be zero, so that the inner area of the fire-resistant layer can be set as a closed heat-insulating area, and the outer ring area 22a of the fire-resistant layer can allow the pressure-relief air flow to circulate.

[0214] Since the inner area of the fire-resistant layer is closed and has a heat-insulating function, the pressure-relief air flow cannot directly flow through the inner area of the fire-resistant layer to the downstream inner area of the fire-resistant layer 2, thereby reducing the generation of combustion heat in the downstream inner area. In addition, the inner area of the fire-resistant layer can effectively slow down the transfer of the combustion heat of the outer ring area 22a of the fire-resistant layer to the inside, so a large amount of combustion heat can be quickly dissipated outward in the outer ring area 22a of the fire-resistant layer, thereby effectively prolonging the fire-blocking duration.

[0215] In a specific embodiment, refer to Figure 23, the fire-resistant layer 2 may include a first closed heat-insulating disc 23a and a plurality of first fire-blocking discs 23b. Among them, the outer ring area 22a of the fire-resistant layer and the inner area of the fire-resistant layer are both disposed on the first closed heat-insulating disc 23a. A plurality of first fitting openings formed at intervals in the circumferential direction are provided in the outer ring area 22a of the fire-resistant layer of the first closed heat-insulating disc 23a, and the plurality of first fire-blocking discs 23b are respectively fitted into the plurality of first fitting openings.

[0216] With such an arrangement, the plurality of first fire-blocking discs 23b are all available for the pressure-relief air flow to pass through, thereby ensuring the flowability of the outer ring area 22a of the fire-resistant layer. In addition to the area where the plurality of first fire-blocking discs 23b are fitted, the remaining areas in the first closed heat-insulating disc 23a are not available for the pressure-relief air flow to pass through, and at the same time, it has a heat-insulating function, which can not only effectively slow down the transfer of the combustion heat in the outer ring area 22a of the fire-resistant layer to the inside, but also slow down the heat transfer between the plurality of first fire-blocking discs 23b, so that more combustion heat is dissipated to the outside atmosphere.

[0217] Referring to Figure 24 , when the fire-resistant layer 2 is provided with an outer ring area 22a, an inner ring area 22b, and an intermediate area 22c of the fire-resistant layer, the porosity of the inner ring area 22b of the fire-resistant layer can be zero. Thus, the inner ring area 22b of the fire-resistant layer can be set as a closed heat-insulating area, while the outer ring area 22a and the intermediate area 22c of the fire-resistant layer can both allow the pressure-relief air flow to pass through.

[0218] The above arrangement takes into account the flow efficiency of the pressure-relief air flow and retains the flowability of the intermediate area 22c of the fire-resistant layer. At the same time, the inner ring area 22b of the fire-resistant layer is closed and has a heat-insulating function, which can effectively slow down the transfer of the combustion heat in the outer ring area 22a of the fire-resistant layer to the intermediate area 22c of the fire-resistant layer, so as to prevent a large amount of combustion heat from accumulating in the intermediate area 22c of the fire-resistant layer and causing backfire and burn-through phenomena. A large amount of combustion heat can be quickly dissipated outward from the outer ring area 22a of the fire-resistant layer, thereby effectively extending the fire-blocking duration.

[0219] In a specific embodiment, referring to Figure 26 , the fire-resistant layer 2 may include a second closed heat-insulating disc 24a, a plurality of second fire-blocking discs 24b, and a single third fire-blocking disc 24c. Among them, the outer ring area 22a, the inner ring area 22b, and the intermediate area 22c of the fire-resistant layer are all disposed on the second closed heat-insulating disc 24a. A plurality of second fitting openings formed at intervals in the circumferential direction are provided in the outer ring area 22a of the fire-resistant layer of the second closed heat-insulating disc 24a, and the plurality of second fire-blocking discs 24b are respectively fitted into the plurality of second fitting openings. A third fitting opening is provided in the intermediate area 22c of the fire-resistant layer of the second closed heat-insulating disc 24a, and the third fire-blocking disc 24c is fitted into the third fitting opening.

[0220] With such a setting, both the third fire - blocking disc 24c and the multiple second fire - blocking discs 24b allow the pressure - relief air flow to pass through, thus ensuring the flowability of the middle area 22c and the outer - ring area 22a of the fire - resistant layer. In the second closed heat - insulating disc 24a, except for the areas where the third fire - blocking disc 24c and the multiple second fire - blocking discs 24b are embedded, the rest of the area does not allow the pressure - relief air flow to pass through, and at the same time has a heat - insulating function. It can not only effectively slow down the transfer of the combustion heat in the outer - ring area 22a of the fire - resistant layer to the middle area 22c of the fire - resistant layer, but also slow down the heat transfer between the multiple second fire - blocking discs 24b, enabling more combustion heat to be dissipated to the outside atmosphere.

[0221] In a specific embodiment, referring to Figure 25 , the fire - resistant layer 2 may include a fire - blocking ring 25a, a closed heat - insulating ring 25b, and a fourth fire - blocking disc 25c nested in sequence from the outside to the inside. Among them, the outer - ring area 22a of the fire - resistant layer is arranged on the fire - blocking ring 25a, the inner - ring area 22b of the fire - resistant layer is arranged on the closed heat - insulating ring 25b, and the middle area 22c of the fire - resistant layer is arranged on the fourth fire - blocking disc 25c.

[0222] With such a setting, both the fire - blocking ring 25a and the fourth fire - blocking disc 25c allow the pressure - relief air flow to pass through, thus ensuring the flowability of the outer - ring area 22a and the middle area 22c of the fire - resistant layer. The closed heat - insulating ring 25b does not allow the pressure - relief air flow to pass through, and at the same time has a heat - insulating function, which can effectively slow down the transfer of the combustion heat in the outer - ring area 22a of the fire - resistant layer to the middle area 22c of the fire - resistant layer, enabling more combustion heat to be dissipated to the outside atmosphere.

[0223] It should be noted that the above - mentioned first closed heat - insulating disc 23a, second closed heat - insulating disc 24a, closed heat - insulating ring 25b, or other forms of closed heat - insulating structures should be made of materials with low thermal conductivity. The inside of these closed heat - insulating structures can be set as a hollow structure, for example. In the hollow state, it can be vacuum - treated or filled with low - thermal - conductivity materials to achieve good heat - insulating performance.

[0224] Stacked porous refractory layer

[0225] The fire - resistant layer 2 can adopt structures such as a corrugated - plate fire - blocking disc with a porous structure, a sintered - type porous fire - resistant layer, and a stacked - type porous fire - resistant layer. In this embodiment, specifically for the stacked - type porous fire - resistant layer, some specific embodiments that can obtain better effects of extending the fire - blocking duration are provided.

[0226] In a specific embodiment, referring to Figure 27 , the stacked - type porous fire - resistant layer may include a first - layer shell 26a and multiple stacked particles 26b stacked inside the first - layer shell 26a.

[0227] Both the first layer of shell 26a and the stacked particles 26b have high temperature resistance. There are multiple particle gaps formed between the multiple stacked particles 26b, thus forming a porous structure, and therefore having a certain fluidity. In addition, a plurality of first layer of shell through holes are provided on both the upstream side wall and the downstream side wall of the first layer of shell 26a. The pressure relief air flow can flow into the fire-resistant layer through the plurality of first layer of shell through holes on the upstream side wall, then flow through the multiple particle gaps to the downstream side wall, and finally flow out of the fire-resistant layer through the plurality of first layer of shell through holes on the downstream side wall. In order to ensure that the stacked particles 26b do not fall out of the first layer of shell through holes, the diameter of the first layer of shell through holes should be smaller than the diameter of the stacked particles 26b.

[0228] It should be noted that there is a risk that the multiple stacked particles 26b may expand due to heat, causing the particle gaps in some areas to expand excessively. At this time, the air flow rate in the particle gaps in these areas increases excessively, which is likely to cause flashback and lead to fire arrest failure. Therefore, the thermal deformation of the stacked particles 26b should be minimized.

[0229] For example, the distance between the upstream inner side wall and the downstream inner side wall of the first layer of shell 26a can be made the same as the total stacking thickness of the multiple stacked particles 26b along the axis of the stacked porous fire-resistant layer, so as to compact the multiple stacked particles 26b, which can effectively reduce the thermal expansion amplitude of the multiple stacked particles 26b, avoid excessive expansion of the particle gaps, and thus effectively reduce the probability of fire arrest failure.

[0230] In addition, the diameter d1 of the stacked particles 26b and the total stacking thickness T3 of the multiple stacked particles 26b along the axis of the stacked porous fire-resistant layer are related to the gas explosion grade. To achieve a better effect of extending the fire arrest duration, d1 and T3 can be set according to the following relational formula, and the relational formula is as follows:

[0231] When the pressure relief air flow is Class IIA gas, 1 ≤ [0.068ln(d1) + 0.31] * d1 / [(0.69 - 0.068ln(d1)] ≤ 1.5;

[0232] When the pressure relief air flow is Class IIB3 gas, 0.6 ≤ [0.068ln(d1) + 0.31] * d1 / [(0.69 - 0.068ln(d1)] ≤ 1.2;

[0233] T3 ≥ d1 / [ξ(1 - ξ)MESG], where MESG is the maximum experimental safe gap, MESG (maximum experimental safe gap). For all concentrations of the measured gas or vapor, when the internal mixture is ignited, it is the maximum gap between two parts of an internal cavity that passes a 25 mm long flame path to prevent the external gas mixture from being ignited. The safe gap is measured according to IEC60079 - 20 - 1:2010.

[0234] If the combustible gas is a mixed gas, its MESG value can be calculated based on its different gas components, or simplified to refer to the MESG value of a typical gas of the corresponding explosion class. For example, for Group IIA gases, propane is selected as the representative gas, and its MESG value is 0.93 mm; for Group IIB3 gases, ethylene is selected as the representative gas, and its MESG value is 0.67 mm; for Group IIC gases, hydrogen is selected as the representative gas, and its MESG value is 0.31 mm.

[0235] For the stacked porous fire-resistant layer, the pressure-relief air flow needs to pass through the gaps between the stacked particles. When the particle size of the stacked particles 26b is larger, the gaps between the stacked particles are also larger, and too large gaps between the stacked particles will cause the flame to burn in the gaps, thereby triggering flashback and resulting in fire-blocking failure.

[0236] And the above relationship limits the equivalent pore size represented by the gap value formed between the stacked particles 26b, which can achieve flame quenching between the pores, and then achieve fire blocking. At the same time, in order to ensure the flow performance, the total stacked thickness T3 is limited.

[0237] In a specific embodiment, the stacked porous fire-resistant layer may include a second shell and a plurality of lightweight spheres stacked inside the second shell.

[0238] Both the second shell and the lightweight spheres have high temperature resistance. There are multiple sphere gaps formed between the plurality of lightweight spheres, thus forming a porous structure, and thus having a certain fluidity. In addition, a plurality of second shell through holes are provided on both the upstream side wall and the downstream side wall of the second shell. The pressure-relief air flow can flow into the interior of the fire-resistant layer through the plurality of second shell through holes on the upstream side wall, then flow through the multiple sphere gaps to the downstream side wall, and finally flow out of the fire-resistant layer through the plurality of second shell through holes on the downstream side wall. In order to ensure that the lightweight spheres will not fall out of the second shell through holes, the diameter of the second shell through holes should be smaller than the diameter of the lightweight spheres.

[0239] Particularly, due to the small mass of the lightweight spheres, when the pressure-relief air flow passes through the multiple sphere gaps, it can drive the plurality of lightweight spheres to rotate, realizing the cold and hot cycle of the lightweight spheres, prolonging the heat transfer time, and being beneficial to improving the fire-blocking performance.

[0240] Convex design of combustion side refractory layer

[0241] By protruding at least a part of the downstream side surface of the combustion-side fire-resistant layer 21a downward, the area of the downstream side surface of the combustion-side fire-resistant layer 21a is enlarged, which can strengthen the heat dissipation effect of the downstream side surface, effectively improve the problem of combustion heat accumulation, and thus prolong the fire-blocking duration of the combustion-side fire-resistant layer 21a.

[0242] For example, the downstream side of the combustion-side fire-resistant layer 21a can be set as a fire-resistant layer curved surface, which has at least one convex position and can be in different specific forms such as a variable-curvature curved surface or a constant-curvature curved surface. When a constant-curvature curved surface with a single convex position is adopted, the fire-resistant layer curved surface is a local spherical surface (i.e., a part of a complete spherical surface). In this way, it is possible to balance the improvement of the heat dissipation effect and the simplification of processing, which is beneficial to reducing the production cost.

[0243] In other words, this embodiment does not limit the specific form of the convex area on the downstream side of the combustion-side fire-resistant layer 21a, as long as it is beneficial to improving the heat dissipation effect.

[0244] In a specific embodiment, referring to Figure 28 , the combustion-side fire-resistant layer 21a includes a fire-resistant layer disc portion 27a and a fire-resistant layer convex portion 27b connected to the downstream side of the fire-resistant layer disc portion 27a. At this time, the downstream side surface of the fire-resistant layer convex portion 27b is set as a local spherical surface protruding downstream. In this way, in the downstream part of the combustion-side fire-resistant layer 21a, the fire-resistant layer convex portion 27b can improve the heat dissipation effect. In the upstream part of the combustion-side fire-resistant layer 21a, the shape of the fire-resistant layer disc portion 27a is the same as that of the protection-side fire-resistant layer 21b. The upstream side surfaces of the fire-resistant layer disc portion 27a and the protection-side fire-resistant layer 21b are both flat surfaces, which can ensure that the distance between the upstream side surface of the fire-resistant layer disc portion 27a and the downstream side surface of the protection-side fire-resistant layer 21b is the same everywhere within the radial range, avoiding enhanced heat conduction due to too small a distance or smoldering due to too large a distance in a local area.

[0245] In addition, the radian corresponding to the local spherical surface is β, which is related to the structural dimensions of the combustion-side fire-resistant layer 21a and the fire resistance and burning resistance level.

[0246] The fire resistance and burning resistance level is classified according to ISO16852. Generally, the commonly used fire resistance and burning resistance levels are IIA, IIB3, and IIC, and their typical representative combustible gases are n-hexane, ethylene, and hydrogen, respectively.

[0247] To better represent the relationship between β and the structural dimensions of the combustion-side fire-resistant layer 21a and the fire resistance and burning resistance level, the MESG values of the typical representative combustible gases (n-hexane, ethylene, and hydrogen) can be taken as the characterization method of the fire resistance and burning resistance level. At this time, it satisfies:

[0248] β = 3.78ε -0.8 arctan(T4 / R1);

[0249] where ε is the MESG value of the typical representative combustible gases n-hexane, ethylene, and hydrogen, R1 is the radius of the fire-resistant layer disc portion 27a, and T4 is the thickness of the fire-resistant layer disc portion 27a.

[0250] By designing the fire-resistant layer 21a on the combustion side through the above relationship, a better effect of extending the fire-blocking duration can be obtained.

[0251] High-temperature resistant coating

[0252] To improve the fire-resistant and burn-resistant performance, a high-temperature resistant coating can be applied at least on the downstream side surface of the fire-resistant layer 2 itself. Preferably, a high-temperature resistant coating that does not have performance damage under long-term combustion conditions of not less than 2 hours and above 450°C is applied.

[0253] In a specific embodiment, the high-temperature resistant coating is arranged to cover the outer surface of the fire-resistant layer 2, including the entire surface composed of the downstream side surface, upstream side surface, peripheral wall surface, surface of holes or gaps, etc. of the fire-resistant layer 2 itself, so as to improve the fire-resistant and burn-resistant performance of the fire-resistant layer 2 with a larger area.

[0254] In a specific embodiment, for the combustion-side fire-resistant layer 21a, a high-temperature resistant coating with a high heat radiation rate or a high reflectivity is preferably applied. For example, the reflectivity of the high-temperature resistant coating is not less than 70%, and preferably, the reflectivity is not less than 90%.

[0255] In a specific embodiment, the thickness of the high-temperature resistant coating applied to the combustion-side fire-resistant layer 21a is 200μm to 500μm, and preferably, the thickness is 300μm to 500μm.

[0256] In a specific embodiment, for the protection-side fire-resistant layer 21b, a high-temperature resistant coating with a low thermal conductivity is preferably applied. For example, the thermal conductivity of the high-temperature resistant coating is not greater than 0.2W / (m·K).

[0257] In a specific embodiment, the thickness of the high-temperature resistant coating applied to the protection-side fire-resistant layer 21b is 20μm to 50μm.

[0258] In a specific embodiment, the thickness of the high-temperature resistant coating is T t , at this time, the fire-blocking gap characteristic value of the fire-resistant layer 2 is h g , the thickness of the fire-resistant layer 2 is T0, and it satisfies:

[0259]

[0260] T0≥3.14e 1.31MESG+1.88 ;

[0261] Among them, MESG is the maximum experimental safe gap. For all concentrations of the tested gas or vapor, when the internal mixture is ignited, it is the maximum gap between the two parts of the internal cavity through a 25mm long flame path to prevent the external gas mixture from being ignited. The safety gap is measured in accordance with IEC60079-20-1:2010.

[0262] It should be noted that the characteristic value of the fire-resistant gap h of the refractory layer 2 is g It is closely related to the fire resistance and burning resistance. When the characteristic value of the fire resistance gap h g When it is larger, the flow rate of the pressure relief airflow that can flow is larger, and its combustion heat is high, so that more heat per unit area is transferred to the downstream refractory layer 2, thereby affecting the fire-resistant and refractory effect; and when the characteristic value of the fire-resistant gap h g When it is smaller, although the flow rate of the pressure relief air flow is smaller and the combustion heat is low, the circulation performance is poor. Therefore, in order to obtain better circulation performance in practical applications, a larger burn-resistant layer area is required. However, as the area of ​​the burn-resistant layer increases, the total combustion heat does not decrease. The heat in the middle area of ​​the burn-resistant layer will be more difficult to dissipate due to the increase in the area of ​​the burn-resistant layer, thereby affecting the fire-retardant and burn-resistant performance.

[0263] In the case of high temperature resistant coating, the characteristic value of the fire barrier gap of the burning resistant layer 2 is h g changes, so preferably, the characteristic value of the fire-blocking gap is h through the above relationship g And the characteristic value of the fire-blocking gap is h g Thickness T of high temperature resistant coating t etc. to limit.

[0264] Long-term fire resistance working condition not less than 2 hours

[0265] At present, some domestic storage tanks or tank areas are difficult to meet the nitrogen sealing requirements, which will cause the gas phase space to be Zone 1. API2000 recommends that for storage tanks with a gas phase space of Zone 1 after nitrogen sealing (or other gas sealing), the flame arrester or flame arresting breathing valve on the tank should be an atmospheric deflagration type flame arrester with long-term flame retardancy and fire resistance, and the flame retardancy and fire resistance time should be no less than 2 hours. However, it is difficult for existing flame arresters or flame arresting breathing valves to meet the requirement of a fire retardancy and fire resistance time of no less than 2 hours.

[0266] Based on the above concept, the present invention further provides multiple embodiments of long-time fire-blocking structures with a fire-blocking time of not less than 2 hours, and sets multiple comparative examples for comparison to better reflect the effect of the present invention on improving the fire-blocking time.

[0267] In the experimental tests of multiple embodiments and comparative examples, the pipe diameter specification of the pressure relief air inlet end 11 is DN100, and the experimental test medium uses a mixture of n-hexane and air recommended by ISO16852, where the volume fraction of n-hexane in the mixture is 2.1%. In addition, during the experimental test process, the temperature changes on the upstream side and downstream side of the fire-resistant structure are concerned, the duration required for the upstream side temperature to rise by 20°C, and whether the fire can be blocked after burning for 2 hours, etc.

[0268] Example 1:

[0269] Refer to Figure 8 and Figure 18 , and the specific structural parameters in the long-time fire-blocking structure are as follows:

[0270] The cavity 13 adopts a coaxial equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief air inlet end 11 is d, and D = 2d;

[0271] The middle flow guide member 4 adopts a metal circular plate with a diameter of 0.8d, and is spaced 0.25d from the upstream side wall of the cavity 13;

[0272] The first annular flow guide member 5 adopts a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced 0.25d from the middle flow guide member 4;

[0273] The fire-resistant layer 21b on the protection side adopts a corrugated plate fire-blocking disc with a diameter of 2d, a thickness of 15 mm, and a fire-blocking gap value of 0.45 mm;

[0274] The fire-resistant layer 21a on the combustion side adopts a corrugated plate fire-blocking disc with a diameter of 2d, a thickness of 15 mm, and a fire-blocking gap value of 0.45 mm;

[0275] The heat insulation support structure 3 adopts high-temperature resistant metal wires with a cross-sectional diameter of 2 mm. The heat insulation support structure 3 is arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the fire-resistant layer 21a on the combustion side.

[0276] Example 2:

[0277] Refer to Figure 4 , Figure 5 and Figure 18 , and the specific structural parameters in the long-time fire-blocking structure are as follows:

[0278] The cavity 13 adopts a coaxial equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief air inlet end 11 is d, and D = 2d;

[0279] The middle flow guide member 4 is made of an arc-shaped metal circular plate, and a plurality of through holes are provided in the middle circular area thereof; wherein, along the radial direction of the pressure relief air inlet end 11, the maximum span of the arc-shaped metal circular plate is equal to the diameter d of the pressure relief air inlet end 11; in addition, the most upstream end of the arc-shaped metal circular plate is spaced 0.25d from the upstream side wall of the cavity 13; furthermore, the boundary diameter of the middle circular area of the middle flow guide member 4 is 0.5d, and the total flow area of all the through holes is half of the total area of the middle circular area;

[0280] The protection side fire-resistant layer 21b uses a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0281] The combustion side fire-resistant layer 21a uses a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0282] The heat insulation support structure 3 uses high-temperature resistant metal wires with a cross-sectional diameter of 2 mm, and the heat insulation support structure 3 is arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion side fire-resistant layer 21a.

[0283] Example 3:

[0284] Refer to Figure 10 and Figure 18 , the specific structural parameters in the long-time firestop structure are as follows:

[0285] The cavity 13 uses a coaxial and equal-diameter cavity, the diameter of the cavity 13 is D, the diameter of the pressure relief air inlet end 11 is d, and D = 2d;

[0286] The middle flow guide member 4 uses a metal circular plate with a diameter of 0.8d, and is spaced 0.25d from the upstream side wall of the cavity 13;

[0287] The first annular flow guide member 5 uses a metal annular plate with inner and outer diameters of d and 1.4d respectively, and is axially spaced 0.15d from the middle flow guide member 4;

[0288] The second annular flow guide member 6 uses a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced 0.15d from the first annular flow guide member 5;

[0289] The protection side fire-resistant layer 21b uses a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0290] The combustion side fire-resistant layer 21a uses a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0291] The heat insulation support structure 3 is made of high-temperature resistant metal wire with a cross-sectional diameter of 2 mm. The heat insulation support structure 3 is arranged in a triangle, and the diameter of the circumcircle of the triangle is equal to the diameter of the combustion-side fire-resistant layer 21a.

[0292] Example 4:

[0293] Referring to Figure 24 and Figure 18 , the specific structural parameters in the long-time fire-resistant structure are as follows:

[0294] The cavity 13 adopts a coaxial and equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief and air inlet end 11 is d, and D = 2d;

[0295] The middle flow guide member 4 adopts a metal circular plate with a diameter of 0.8d and is spaced 0.25d from the upstream side wall of the cavity 13;

[0296] The first annular flow guide member 5 adopts a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced 0.25d from the middle flow guide member 4;

[0297] The protection-side fire-resistant layer 21b includes a corrugated plate fire-resistant disc, a closed heat-insulating metal ring, and a corrugated plate fire-resistant ring sleeved in sequence from the inside to the outside. The closed heat-insulating metal ring is provided with a hollow cavity or a low thermal conductivity material is filled in the hollow cavity thereof; for the corrugated plate fire-resistant disc, its diameter is 0.8d, its thickness is 15 mm, and the fire-resistant gap value is 0.45 mm; for the corrugated plate fire-resistant ring, its inner and outer diameters are 1.3d and 1.6d respectively, its thickness is 15 mm, and the fire-resistant gap value is 0.45 mm;

[0298] The combustion-side fire-resistant layer 21a includes a corrugated plate fire-resistant disc, a closed heat-insulating metal ring, and a corrugated plate fire-resistant ring sleeved in sequence from the inside to the outside. The closed heat-insulating metal ring is provided with a hollow cavity or a low thermal conductivity material is filled in the hollow cavity thereof; for the corrugated plate fire-resistant disc, its diameter is 0.8d, its thickness is 15 mm, and the fire-resistant gap value is 0.45 mm; for the corrugated plate fire-resistant ring, its inner and outer diameters are 1.3d and 1.6d respectively, its thickness is 15 mm, and the fire-resistant gap value is 0.45 mm;

[0299] The heat insulation support structure 3 is made of high-temperature resistant metal wire with a cross-sectional diameter of 2 mm. The heat insulation support structure 3 is arranged in a triangle, and the diameter of the circumcircle of the triangle is equal to the diameter of the combustion-side fire-resistant layer 21a.

[0300] Example 5:

[0301] Referring to Figure 9 and Figure 18 , the specific structural parameters in the long-time fire-resistant structure are as follows:

[0302] The cavity 13 is a coaxial equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief and air inlet end 11 is d, and D = 2d;

[0303] The middle flow guide member 4 is a metal circular plate with a diameter of 0.8d, and is spaced 0.25d from the upstream side wall of the cavity 13;

[0304] The first annular flow guide member 5 is a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced 0.25d from the middle flow guide member 4;

[0305] Both of the two protective side fire-resistant layers 21b are corrugated plate fire-resistant discs with a diameter of 2d, a thickness of 15 mm, and a fire-resistant gap value of 0.45 mm;

[0306] The combustion side fire-resistant layer 21a is a corrugated plate fire-resistant disc with a diameter of 2d, a thickness of 15 mm, and a fire-resistant gap value of 0.45 mm;

[0307] Both of the two heat insulation support structures 3 are high-temperature resistant metal wires with a cross-sectional diameter of 2 mm. Both of the two heat insulation support structures 3 are arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion side fire-resistant layer 21a.

[0308] Example 6:

[0309] Refer to Figure 8 and Figure 19 , the specific structural parameters in the long-term fire-resistant structure are as follows:

[0310] The cavity 13 is a coaxial equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief and air inlet end 11 is d, and D = 2d;

[0311] The middle flow guide member 4 is a metal circular plate with a diameter of 0.8d, and is spaced 0.25d from the upstream side wall of the cavity 13;

[0312] The first annular flow guide member 5 is a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced 0.25d from the middle flow guide member 4;

[0313] The protective side fire-resistant layer 21b is a corrugated plate fire-resistant disc with a diameter of 2d, a thickness of 15 mm, and a fire-resistant gap value of 0.45 mm;

[0314] The combustion side fire-resistant layer 21a is a corrugated plate fire-resistant disc with a diameter of 2d, a thickness of 15 mm, and a fire-resistant gap value of 0.45 mm;

[0315] The heat insulation support structure 3 is a double-layer high-temperature resistant metal wire. For each layer of high-temperature resistant metal wire, its cross-sectional diameter is 2 mm, and it is arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion side fire-resistant layer 21a.

[0316] Example 7:

[0317] Referring to Figure 8 and Figure 21 , the specific structural parameters in the long-time fire-resistant structure are as follows:

[0318] The cavity 13 adopts a coaxial equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief air inlet end 11 is d, and D = 2d;

[0319] The middle flow guide member 4 adopts a metal circular plate with a diameter of 0.8d and is spaced 0.25d from the upstream side wall of the cavity 13;

[0320] The first annular flow guide member 5 adopts a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced 0.25d from the middle flow guide member 4;

[0321] The protective side fire-resistant layer 21b adopts a corrugated plate fire-resistant disc with a diameter of 2d, a thickness of 15 mm, and a fire-resistant gap value of 0.45 mm;

[0322] The combustion side fire-resistant layer 21a adopts a corrugated plate fire-resistant disc with a diameter of 2d, a thickness of 15 mm, and a fire-resistant gap value of 0.45 mm;

[0323] The heat insulation support structure 3 adopts a high-temperature resistant metal wire with a heat insulation support body part 32a and a heat insulation support protruding part 32b. The cross-sectional diameter of the heat insulation support body part 32a is 2 mm, the thickness of the heat insulation support protruding part 32b protruding from the heat insulation support body part 32a is 1 mm, and the heat insulation support protruding part 32b is a hemispherical structure.

[0324] Example 8:

[0325] Referring to Figure 6 and Figure 18 , the long-time fire-resistant structure can be applied as a breathing valve, and its specific structural parameters are as follows:

[0326] The cavity 13 adopts a coaxial equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief air inlet end 11 is d, and D = 2d;

[0327] A first flange is provided at the upstream end of the pressure relief air inlet end 11;

[0328] The middle flow guide member 4 serves as the pressure relief valve disc 43 of the breathing valve. The pressure relief valve disc 43 is connected to a first guide rod, and the first guide rod can slide in the first guide groove in the upstream and downstream directions. The pressure relief valve disc 43 can switch the on-off state between the cavity 13 and the pressure relief air inlet end 11. When the pressure relief valve disc 43 moves downstream to open and the cavity 13 is communicated with the pressure relief air inlet end 11, the pressure relief valve disc 43 plays a role in guiding and distributing the flow; among them, the diameter of the pressure relief valve disc 43 is d, and it is spaced 0.25d from the upstream side wall of the cavity 13;

[0329] The first annular flow guide member 5 is made of a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced from the middle flow guide member 4 by 0.25d;

[0330] The fire-resistant layer 21b on the protection side adopts a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0331] The fire-resistant layer 21a on the combustion side adopts a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0332] The heat insulation support structure 3 is made of high-temperature resistant metal wires with a cross-sectional diameter of 2 mm. The heat insulation support structure 3 is arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the fire-resistant layer 21a on the combustion side.

[0333] Example 9:

[0334] Referring to Figure 7 and Figure 18 , the long-term firestop structure can be applied to a breather valve, and its specific structural parameters are as follows:

[0335] The cavity 13 adopts a coaxial and equal-diameter cavity. The diameter of the cavity 13 is D, and the diameter of the pressure relief air inlet end 11 is d, and D = 2d;

[0336] A second flange is provided at the upstream end of the pressure relief air inlet end 11;

[0337] The middle flow guide member 4 serves as the pressure relief valve disc 43 of the breather valve. The pressure relief valve disc 43 is connected to a second guide rod, and the second guide rod can slide in the second guide groove in the upstream and downstream directions. The pressure relief valve disc 43 can switch the on-off state between the cavity 13 and the pressure relief air inlet end 11. When the pressure relief valve disc 43 moves downstream to open and the cavity 13 is communicated with the pressure relief air inlet end 11, the pressure relief valve disc 43 plays a role in guiding and distributing the flow; among them, the diameter of the pressure relief valve disc 43 is d, and it is axially spaced from the upstream side wall of the cavity 13 by 0.25d;

[0338] The first annular flow guide member 5 is made of a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced from the middle flow guide member 4 by 0.25d;

[0339] The fire-resistant layer 21b on the protection side adopts a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0340] The fire-resistant layer 21a on the combustion side adopts a corrugated plate firestop disc with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0341] The heat insulation support structure 3 is made of high-temperature resistant metal wire with a cross-sectional diameter of 2 mm. The heat insulation support structure 3 is arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion-side fire-resistant layer 21a.

[0342] Comparative Example 1:

[0343] Refer to Figure 29 , the fire-blocking structure in the figure can be regarded as a structural simplification and adjustment based on the long-time fire-blocking structure provided in Embodiment 1. Except for the differences specifically described below, the structural parameters of the common structures in Comparative Example 1 and Embodiment 1 are the same.

[0344] The difference between Comparative Example 1 and Embodiment 1 is that: the fire-blocking structure in Comparative Example 1 does not have a heat insulation support structure 3, a middle flow guide member 4, and a first annular flow guide member 5, and there is no gap between the combustion-side fire-resistant layer 21a and the protection-side fire-resistant layer 21b.

[0345] Comparative Example 2:

[0346] Continuing with Figure 29 as an example, the difference between Comparative Example 2 and Comparative Example 1 is only that: the fire-blocking gap values of the combustion-side fire-resistant layer 21a and the protection-side fire-resistant layer 21b in Comparative Example 1 are both 0.45 mm, while the fire-blocking gap values of the combustion-side fire-resistant layer 21a and the protection-side fire-resistant layer 21b in Comparative Example 2 are both 0.85 mm.

[0347] The following table shows the comparison of experimental data between Embodiments 1-9 and Comparative Examples 1-2:

[0348]

[0349]

[0350] As can be seen from the above table, the long-time fire-blocking structure of the present invention, when having multiple-layer fire-resistant structures, a heat insulation support structure 3, and adopting an active flow splitting technology at the same time, has been experimentally proven to achieve a fire-blocking and fire-resistant duration of not less than 2 hours, and the fire-blocking effect has been significantly improved compared with the prior art.

[0351] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0352] In the present invention, unless otherwise clearly specified or limited, the terms "installed", "connected", "connected to", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or capable of communicating with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0353] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0354] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A long - time fire - resistant structure with in - cavity flow - guiding function, Characterized in that, The long - time fire - resistant structure includes: A housing (1), provided with a pressure - relief air inlet end (11), a pressure - relief air exhaust end (12), and a cavity (13) connecting the pressure - relief air inlet end (11) and the pressure - relief air exhaust end (12); A fire - resistant structure, arranged at the pressure - relief air exhaust end (12); and A cavity flow - guiding structure, arranged in the cavity (13) and used for dividing the pressure - relief air flow flowing into the cavity (13) from the pressure - relief air inlet end into multiple regional air flows flowing in different regions towards the fire - resistant structure.

2. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 1, Characterized in that, The cavity flow - guiding structure includes: A middle flow - guiding member (4), arranged opposite to the pressure - relief air inlet end (11), and used for dividing the pressure - relief air flow flowing into the cavity (13) from the pressure - relief air inlet end (11) into an outer - region air flow (G11) and an inner - region air flow (G12) flowing in the outer region and the inner region of the cavity (13) respectively.

3. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 2, Characterized in that, The middle flow - guiding member (4) is provided with a flow - through structure (41) running through it, and the middle flow - guiding member (4) is further arranged to divide the pressure - relief air flow into an outer - ring region air flow (G21), an inner - ring region air flow (G22), and a middle - region air flow (G23) which are distributed in sequence from outside to inside in the cavity (13).

4. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 3, Characterized in that, The flow - through structure (41) includes a plurality of flow - through holes formed in the middle circular region of the middle flow - guiding member (4).

5. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 3, Characterized in that, The total flow - through area of the flow - through structure (41) is not greater than one - third of the flow - through area of the pressure - relief air inlet end (11).

6. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 2, Characterized in that, The middle flow - guiding member (4) is a bent plate (42) and the bent convex surface faces the pressure - relief air inlet end (11).

7. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 2, Characterized in that, The middle flow - guiding member (4) is a pressure - relief valve disc (43) used for switching the on - off state between the cavity (13) and the pressure - relief air inlet end (11).

8. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 2, Characterized in that, The axial projection area of the middle flow - guiding member (4) is not greater than the axial projection area of the pressure - relief air inlet end.

9. The long - time fire - resistant structure with in - cavity flow - guiding function according to claim 2, Characterized in that, The diameter of the middle flow guide member (4) is D1, the distance between the middle flow guide member (4) and the inner wall of the upstream end of the cavity (13) is H1, the distance between the middle flow guide member (4) and the inner wall of the downstream end of the cavity (13) is H2, the inner diameter of the cavity (13) is D, and the inner diameter of the pressure relief air inlet end (11) is d, satisfying: Where e is the natural constant.

10. The long-time flame retardant structure with in-cavity flow guiding function according to claim 2, characterized in that, The cavity flow guiding structure further includes: A first annular flow guide member (5), arranged on the downstream side of the middle flow guide member (4), the outer circumferential wall of the first annular flow guide member (5) is spaced from the inner circumferential wall of the cavity (13), and the first annular flow guide member (5) is used for further dividing the outer region air flow (G11) and the inner region air flow (G12) into an outer ring region air flow (G21), an inner ring region air flow (G22) and a middle region air flow (G23) that are sequentially distributed from outside to inside in the cavity (13).

11. The long-time flame retardant structure with in-cavity flow guiding function according to claim 10, characterized in that, The cavity flow guiding structure further includes: A second annular flow guide member (6), arranged on the downstream side of the first annular flow guide member (5), the outer circumferential wall of the second annular flow guide member (6) is spaced from the inner circumferential wall of the cavity (13), and the outer ring radius of the second annular flow guide member (6) is greater than the outer ring radius of the first annular flow guide member (5).

12. The long-time flame retardant structure with in-cavity flow guiding function according to claim 1, characterized in that, The cavity flow guiding structure is configured to divide the pressure relief air flow flowing into the cavity (13) into an outer region air flow (G11) and an inner region air flow (G12) that flow in the outer region and the inner region of the cavity (13) respectively, and make the flow rate of the outer region air flow (G11) greater than the flow rate of the inner region air flow (G12), and / or make the flow rate of the outer region air flow (G11) greater than the flow rate of the inner region air flow (G12).

13. The long-time flame retardant structure with in-cavity flow guiding function according to claim 1, characterized in that, The cavity flow guiding structure is configured to divide the pressure relief air flow flowing into the cavity (13) into an outer ring region air flow (G21), an inner ring region air flow (G22) and a middle region air flow (G23) that are sequentially distributed from outside to inside in the cavity (13), and make the flow rates of the outer ring region air flow (G21), the middle region air flow (G23) and the inner ring region air flow (G22) decrease from large to small, and / or make the flow rates of the outer ring region air flow (G21), the middle region air flow (G23) and the inner ring region air flow (G22) decrease from large to small.

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