Long-time fire retardant structure with convex design

Abstract

The invention relates to the field of flame arresters, and discloses a long-time flame arresting structure with a convex design, 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 comprises a plurality of burning-resistant layers which are sequentially arranged at intervals in the axial direction of the pressure relief exhaust end, the burning-resistant layer located at the most downstream forms a burning side burning-resistant layer, and the burning-resistant layer located at the upstream of the burning side burning-resistant layer forms a protection side burning-resistant layer; at least partial area of the downstream side surface of the combustion-side burning-resistant layer protrudes towards the downstream; and the flow guide structure is arranged in the shell, is positioned on the upstream of the burning-resistant structure and is used for dividing the pressure relief airflow in the shell into a plurality of regional airflow flowing towards different regions of the burning-resistant structure. Thus, the burning-resistant layer on the burning side has a large heat dissipation area during burning, and the flow guide structure is beneficial to heat dispersion, so that the risks of tempering and burnthrough phenomena can be effectively reduced, and the fire retardance duration is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of flame arresters, and particularly relates to a long-time flame retardant structure with a convex design. 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 phase pressure in the tank will increase. To prevent overpressure damage or pressure buildup in 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 retardant function, and a product that has undergone an overall flame retardant test should be selected for an all-weather flame retardant breather valve.

[0003] However, most of the combustible gases exhaled from the storage tank are premixed combustible gases with high calorific values, and the existing pipe end flame arresters or flame retardant 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, thus causing the accident to expand further. Summary of the Invention

[0004] The purpose of the present invention is to provide a long-time flame retardant structure with a convex design, 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 accident from expanding further and leave more preparation time for emergency rescue.

[0005] To achieve the above purpose, the present invention provides a long-time flame retardant structure with a convex design, 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, the burning resistance structure includes a plurality of burning resistance layers arranged at intervals along the axial direction of the pressure relief air outlet end, the burning resistance layer located at the most downstream forms a burning side burning resistance layer, the burning resistance layer located upstream of the burning side burning resistance layer forms a protection side burning resistance layer, and at least part of the downstream side surface of the burning side burning resistance layer protrudes downward; and

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

[0009] In some embodiments, the downstream side surface of the burning side burning resistance layer forms a burning resistance layer curved surface.

[0010] In some embodiments, the curved surface of the fire-resistant layer is formed as a variable-curvature curved surface or a constant-curvature curved surface with a single convex position.

[0011] In some embodiments, the curved surface of the fire-resistant layer is formed as a local spherical surface.

[0012] In some embodiments, the fire-resistant layer on the combustion side includes a fire-resistant layer disc portion and a fire-resistant layer convex portion connected to the downstream side of the fire-resistant layer disc portion. The downstream side surface of the fire-resistant layer convex portion is a local spherical surface protruding downward.

[0013] In some embodiments, the radius of the fire-resistant layer disc portion is R1 and the thickness is T4, and the radian corresponding to the local spherical surface is β, satisfying: β = 3.78ε -0.8 arctan(T4 / R1); where ε is the MESG value of typical representative combustible gases such as n-hexane, ethylene, and hydrogen, and MESG is the maximum experimental safety gap.

[0014] In some embodiments, the flow guiding structure includes:

[0015] A cavity flow guiding structure, disposed in the cavity, and configured to divide the pressure relief airflow flowing into the cavity into an outer region airflow and an inner region airflow that flow in the outer region and the inner region of the cavity respectively, and make the flow velocity of the outer region airflow greater than that of the inner region airflow, and / or make the flow rate of the outer region airflow greater than that of the inner region airflow.

[0016] In some embodiments, the flow guiding structure includes:

[0017] A cavity flow guiding structure, disposed in the cavity, and configured to divide the pressure relief airflow flowing into the cavity into an outer ring region airflow, an inner ring region airflow, and a middle region airflow that are sequentially distributed from the outside to the inside in the cavity, and make the flow velocities of the outer ring region airflow, the middle region airflow, and the inner ring region airflow decrease in sequence, and / or make the flow rates of the outer ring region airflow, the middle region airflow, and the inner ring region airflow decrease in sequence.

[0018] In some embodiments, the flow guiding structure includes:

[0019] An air inlet end flow guiding structure, disposed in the pressure relief air inlet end, and configured to divide the pressure relief airflow flowing into the pressure relief air inlet end into an outer layer region airflow and an inner region airflow that flow in the outer layer region and the inner region of the pressure relief air inlet end respectively, and make the flow velocity of the outer layer region airflow greater than that of the inner region airflow, and / or make the flow rate of the outer layer region airflow greater than that of the inner region airflow.

[0020] In some embodiments, the diversion structure includes:

[0021] An intake end diversion structure, which is arranged inside the pressure relief intake end and is used to divide the pressure relief air flow flowing into the pressure relief intake end into an outer region air flow, an inner region air flow, and a middle region air flow that flow in the outer region, the inner region, and the middle region in the pressure relief intake end respectively, and makes the flow velocity of the outer region air flow, the flow velocity of the middle region air flow, and the flow velocity of the inner region air flow be distributed from large to small, and / or makes the flow rate of the outer region air flow, the flow rate of the middle region air flow, and the flow rate of the inner region air flow be distributed from large to small.

[0022] In the long-time fire resistance structure of the present invention, since at least one protective side refractory layer is provided upstream of the combustion side refractory layer, and at least part of the downstream side surface of the combustion side refractory layer protrudes downward, when the combustion side refractory layer burns, the heat dissipation area of the combustion heat can be greatly increased, the risk that the combustion side refractory layer is burned through due to heat accumulation can be effectively reduced, and even if the combustion side refractory layer is burned through, the protective side refractory layer can also take over to play a fire resistance role. The diversion structure can actively divert the pressure relief air flow flowing into the housing, and the multiple divided regional air flows can flow through different regions of the refractory structure, thereby dispersing the heat in the refractory structure, effectively reducing the risk of flashback and burn-through, and effectively prolonging the fire resistance time.

[0023] 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

[0024] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific embodiments, they are used 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, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings. In the drawings:

[0025] Figure 1 is a schematic diagram of a long-time fire resistance structure in a specific embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of another long-time fire resistance structure in a specific embodiment of the present invention. The long-time fire resistance structure in the figure is provided with two protective side refractory layers;

[0027] Figure 3 is a schematic diagram of another long-time fire resistance structure in a specific embodiment of the present invention. The long-time fire resistance structure in the figure is provided with a middle diversion member;

[0028] Figure 4Schematic diagram of another long-time fire-blocking structure in the specific implementation manner of the present invention. The long-time fire-blocking 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;

[0029] Figure 5 Axial schematic diagram of a middle flow guide member in the specific implementation manner of the present invention. The middle flow guide member in the figure includes a middle circular area provided with a flow-through structure;

[0030] Figure 6 Schematic diagram of a long-time fire-blocking structure applied as a breathing valve in the specific implementation manner of the present invention;

[0031] Figure 7 Schematic diagram of a long-time fire-blocking structure applied as a breather valve in the specific implementation manner of the present invention;

[0032] Figure 8 Schematic diagram of another long-time fire-blocking structure in the specific implementation manner of the present invention. The long-time fire-blocking structure in the figure is provided with a middle flow guide member and a first annular flow guide member;

[0033] Figure 9 Schematic diagram of another long-time fire-blocking structure in the specific implementation manner of the present invention. The long-time fire-blocking 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;

[0034] Figure 10 Schematic diagram of another long-time fire-blocking structure in the specific implementation manner of the present invention. The long-time fire-blocking 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;

[0035] Figure 11 Regional air flow distribution diagram in the cavity when a cavity flow guide structure is set for the long-time fire-blocking structure in the specific implementation manner of the present invention;

[0036] Figure 12 Regional air flow distribution diagram in the cavity when a cavity flow guide structure is set for another long-time fire-blocking structure in the specific implementation manner of the present invention;

[0037] Figure 13 For Figure 3 Schematic diagram of the structural parameters of the long-time fire-blocking structure in;

[0038] Figure 14 Schematic diagram of an air inlet end flow guide structure in the specific implementation manner of the present invention;

[0039] Figure 15 Regional air flow distribution diagram in the cavity when an air inlet end flow guide structure is set for the long-time fire-blocking structure in the specific implementation manner of the present invention;

[0040] Figure 16The regional air flow distribution diagram in the cavity when setting the air inlet end diversion structure for another long-time fire resistance structure in the specific embodiment of the present invention;

[0041] Figures 17 to 19 The axial schematic diagram of three optional heat insulation support structures in the specific embodiment of the present invention;

[0042] Figures 20 to 21 The side view of two other optional heat insulation support structures in the specific embodiment of the present invention;

[0043] Figure 22 The schematic diagram of another long-time fire resistance structure in the specific embodiment of the present invention. In the figure, each fire-resistant layer is provided with a fire-resistant layer outer ring area and a fire-resistant layer inner side area, and the fire-resistant layer inner side area can be a closed heat insulation area;

[0044] Figure 23 The axial schematic diagram of a fire-resistant layer in the specific embodiment of the present invention. The fire-resistant layer in the figure includes a first closed heat insulation disc and a plurality of first fire-blocking discs;

[0045] Figure 24 The schematic diagram of another long-time fire resistance structure in the specific embodiment of the present invention. In the figure, each fire-resistant layer is provided with a fire-resistant layer outer ring area, a fire-resistant layer inner ring area and a fire-resistant layer middle area, and the fire-resistant layer inner ring area can be a closed heat insulation area;

[0046] Figure 25 The axial schematic diagram of another fire-resistant layer in the specific embodiment of the present invention. The fire-resistant layer in the figure includes a fire-blocking ring, a closed heat insulation ring and a fourth fire-blocking disc;

[0047] Figure 26 The axial schematic diagram of another fire-resistant layer in the specific embodiment of the present invention. The fire-resistant layer in the figure includes a second closed heat insulation disc, a plurality of second fire-blocking discs and a single third fire-blocking disc;

[0048] Figure 27 The schematic diagram of a stacked porous fire-resistant layer in the specific embodiment of the present invention;

[0049] Figure 28 The schematic diagram of a combustion-side fire-resistant layer in the specific embodiment of the present invention. The combustion-side fire-resistant layer in the figure is provided with a fire-resistant layer disc part and a fire-resistant layer convex part;

[0050] Figure 29 The schematic diagram of a fire resistance structure for comparative experiment in the specific embodiment of the present invention. There is no gap left between the combustion-side fire-resistant layer and the protection-side fire-resistant layer of the fire resistance structure in the figure.

[0051] Explanation of reference numerals

[0052] 1 Housing;

[0053] 11 Pressure relief intake end, 12 pressure relief exhaust end, 13 cavity;

[0054] 2 Fire-resistant layer;

[0055] 21a Combustion side fire-resistant layer, 21b Protection side fire-resistant layer;

[0056] 22a Outer ring area of fire-resistant layer, 22b Inner ring area of fire-resistant layer, 22c Middle area of fire-resistant layer;

[0057] 23a First closed heat-insulating disc, 23b First fire-blocking disc;

[0058] 24a Second closed heat-insulating disc, 24b Second fire-blocking disc, 24c Third fire-blocking disc;

[0059] 25a Fire-blocking ring, 25b Closed heat-insulating ring, 25c Fourth fire-blocking disc;

[0060] 26a First layer of shell, 26b Stacked particles;

[0061] 27a Disc part of fire-resistant layer, 27b Convex part of fire-resistant layer;

[0062] 3 Heat-insulating support structure;

[0063] 31 Heat-insulating support unit;

[0064] 32a Heat-insulating support body part, 32b Heat-insulating support protruding part;

[0065] 4 Middle part flow guide;

[0066] 41 Flow-through structure, 42 Bending plate, 43 Pressure relief valve disc;

[0067] 5 First annular flow guide;

[0068] 6 Second annular flow guide;

[0069] 7 First circumferential partition;

[0070] 8 Second circumferential partition;

[0071] G11 Outer region air flow, G12 Inner region air flow;

[0072] G21 Outer ring region air flow, G22 Inner ring region air flow, G23 Middle region air flow;

[0073] G31 Outer layer region air flow, G32 Inner region air flow, G321 Inner layer region air flow, G322 Middle region air flow Specific implementation method

[0074] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and understanding the present invention, and are not used to limit the present invention.

[0075] The following describes a long-time flame arrestor structure according to the present invention with reference to the accompanying drawings.

[0076] Through analysis, when the existing pipe-end flame arrestor or flame arrestor breather valve burns for a long time, the combustion heat has three heat transfer directions. One is to transfer to the inside of the flame arrestor through heat conduction and thermal radiation. The second is to be carried away by part of the combustible gas discharged by the flame arrestor. The third is to dissipate to the external atmosphere through heat conduction, thermal radiation, etc.

[0077] The second and third heat transfer directions mentioned above are both beneficial to preventing the combustion heat from accumulating in the flame arrestor, making the flame arrestor effect better. The first heat transfer direction is not the case. The transfer of combustion heat to the inside of the flame arrestor will increase the risk of flashback and burning through of the flame arrestor.

[0078] However, due to the constraints of the existing pipe-end flame arrestor or flame arrestor breather valve on its flame arrestor structure and internal structure form, when the flame arrestor structure burns, the heat transfer direction of the combustion heat is mainly the first one mentioned above. Therefore, the combustion heat will quickly accumulate in the flame arrestor structure and will accumulate in a local area of the flame arrestor structure (usually the middle area), and it is easy to have a burning-through phenomenon in this local area.

[0079] To solve the deficiencies of the existing technology, the long-time flame arrestor 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 arrestor structure.

[0080] Multiple alternative embodiments of the long-time flame arrestor 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 arrestor duration.

[0081] In each alternative embodiment, first refer to Figure 1 , the basic structure of the long-time flame arrestor 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 arrestor 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 provided in the fire-resistant structure.

[0082] When there is an ignition source in the outside world and the pressure-relief airflow is ignited on the downstream side of the fire-resistant structure, there are the following two working conditions:

[0083] One is the non-long-term fire-resistant working condition. At this time, the pressure-relief airflow does not continuously discharge through the pressure-relief exhaust 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-term flame-retarding structure) of the fire-resistant structure;

[0084] The other is the long-term fire-resistant working condition. At this time, the pressure-relief airflow continuously discharges through the pressure-relief exhaust 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.

[0085] Next, several alternative embodiments that can effectively extend the flame-retarding duration will be introduced one by one:

[0086] Airflow control method 1 (cavity diversion structure)

[0087] Referring to Figure 3 and Figure 11 , the long-term flame-retarding structure may include a cavity diversion structure provided in the cavity 13. Specifically, the cavity diversion structure may include a middle diversion member 4 disposed opposite to the pressure-relief inlet end 11. The pressure-relief airflow flowing into the cavity 13 from the pressure-relief inlet end 11 can be divided into an outer-region airflow G11 flowing in the outer region of the cavity 13 and an inner-region airflow G12 flowing in the inner region of the cavity 13 under the diversion action of the middle diversion member 4.

[0088] Compared with the existing long-term combustion working condition of a flame arrester in which the combustion heat accumulates in a local area (usually the middle area) of the flame-retarding structure, resulting in difficult heat dissipation of the combustion heat and even burning through of the flame-retarding structure, the long-term flame-retarding structure of this embodiment can actively divert the pressure-relief airflow flowing into the cavity 13 by setting the middle diversion member 4. The diverted outer-region airflow G11 and inner-region airflow 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-retarding duration.

[0089] Furthermore, referring 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 from the outer periphery of the middle flow guide member 4 and the flow-through structure 41. The pressure relief air flow passing through the outer periphery of the middle flow guide member 4 will be split 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.

[0090] 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 distributed in sequence from outside to inside. This flow field form can disperse the heat in the fire-resistant structure to more different regions, further prolonging the fire resistance duration.

[0091] Refer to Figure 4 , to reduce the resistance of the pressure relief air flow, the middle flow guide member 4 can 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 split at the outer periphery 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 is conducive to more quickly taking away the heat in the cavity 13.

[0092] In addition to being set as the curved plate 42, the middle flow guide member 4 can also be set as other streamline shapes, such as conical, spindle-shaped, water droplet-shaped, etc., and the present invention does not limit this.

[0093] Refer 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 can 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 to open and the cavity 13 is communicated with the pressure relief air inlet end 11, the pressure relief valve disc 43 plays the above-mentioned guiding and splitting roles.

[0094] Refer 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.

[0095] 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, resulting in the problem that the middle region of the burn-resistant structure overheats and cannot be effectively solved.

[0096] 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, 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.

[0097] 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:

[0098] wherein, e is the natural constant, and its value is approximately 2.718.

[0099] 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 the pressure drop is relatively large.

[0100] 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.

[0101] Specifically, the diameter D1 mainly takes into account 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 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 of the diameter D1 is carried out.

[0102] The distance H1 mainly takes into account that the flow-through area required for the pressure-relief air flow to pass through here should be larger than the incoming flow area of the pressure-relief air inlet end 11, so as to reduce the pressure loss caused by the 90° bend.

[0103] 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 refraction 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, and then form a relatively uniform flow velocity distribution. It is mainly derived from fluid mechanics theory, numerical simulation and experimental results.

[0104] 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 diverted 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 diverted when passing through the first annular flow guide member 5. At this time, the airflow on the outer side 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 side of the outer region airflow G11 and the airflow on the outer side of the inner region airflow G12 are diverted when passing through the inner circumferential edge of the first annular flow guide member 5. The diverted airflow close to the inner circumferential edge of the first annular flow guide member 5 is the inner ring region airflow G22, and the diverted airflow far from the inner circumferential edge of the first annular flow guide member 5 (i.e., the diverted airflow flowing in the middle region of the cavity 13) is the middle region airflow G23.

[0105] In other words, overall, after the pressure relief airflow is diverted 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 time.

[0106] 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, 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.

[0107] 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 air flow G21 in the outer ring region, the air flow G22 in the inner ring region, and the air flow G23 in the middle region, so as 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.

[0108] 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 belong to the concept scope of the present invention.

[0109] Airflow control method 2 (inlet end diversion structure)

[0110] 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.

[0111] 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 the difficulty of dissipating the combustion heat and even causing the fire-resistant structure to be burned through, 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 arranging 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 realizing long-time fire resistance.

[0112] Further, referring to Figure 14 and Figure 16, the air inlet 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.

[0113] In other words, overall, when the pressure relief airflow passes through the air inlet 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 distributed in sequence from outside to inside within the pressure relief air inlet end 11. This flow field form can disperse the heat in the fire-resistant structure to more different regions, further extending the fire resistance duration.

[0114] In a specific embodiment, the structural parameter relationship between the fire-resistant structure and the air inlet 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 layer 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 layer 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 layer flow-through structure are S1, S2, and S3 respectively.

[0115] In addition, the inlet end diversion ratios of the annular region between the inner peripheral wall of the pressure relief air inlet 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.

[0116] Furthermore, the total inlet end flow-through area of the air inlet end flow guiding structure is S0.

[0117] Based on the principle of flow conservation, the following relationships are set such that the pressure relief airflow flow rate flowing into the annular region between the inner peripheral wall of the pressure relief air inlet end 11 and the outer peripheral wall of the first circumferential partition 7 is equal to the pressure relief airflow flow rate flowing through the outer layer flow-through structure of the fire-resistant structure, the pressure relief airflow flow rate flowing into the annular region between the first circumferential partition 7 and the second circumferential partition 8 is equal to the pressure relief airflow flow rate flowing through the inner layer flow-through structure of the fire-resistant structure, and the pressure relief airflow flow rate flowing into the inner region of the second circumferential partition 8 is equal to the pressure relief airflow flow rate flowing through the intermediate layer flow-through structure of the fire-resistant structure. The specific relationships are as follows:

[0118] (S1*σ1) / (S0*a)≤2 / 3;

[0119] (S2*σ2) / (S0*b)≥5;

[0120] 1 ≤ (S3 * σ3) / (S0 * c) ≤ 3.

[0121] It should be noted that the air inlet end diversion structure may also be provided with more circumferential partitions other than the first circumferential partition 7 and the second circumferential partition 8 to divide more regional airflows, so as to disperse the heat in the fire-resistant structure as evenly as possible to achieve an excellent effect of extending the fire resistance duration.

[0122] In the present invention, only some optional forms of the air inlet end diversion structure are listed for illustration. It can be understood that other forms of air inlet end diversion structures that can also divide the pressure relief airflows in the pressure relief air inlet 11 into multiple regional airflows should also fall within the scope of the concept of the present invention.

[0123] In addition, in addition to the cavity diversion structure and the air inlet end diversion structure provided above, other forms of diversion structures may also be provided in the housing 1. For example, an integral housing diversion structure that simultaneously occupies the spaces of the cavity 13 and the pressure relief air inlet 11 can also be designed. In other words, the present invention does not limit the specific form of the diversion structure provided in the housing 1. As long as the diversion 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.

[0124] Airflow control method 3 (porosity distribution of refractory structure)

[0125] 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.

[0126] Compared with the existing fire arrester under long-term combustion conditions where the combustion heat accumulates in the local region (usually the middle region) of the fire-resistant structure, resulting in difficult heat dissipation of the combustion heat and even burning through the fire-resistant structure, the long-term fire-resistant 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-term fire resistance.

[0127] Refer to Figure 22 , the fire-resistant layer partition may include 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. 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 area 22a and the fire-resistant layer inner area respectively.

[0128] Further, with reference 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] Flow velocity and flow rate distribution form under airflow control

[0133] It has been proven 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-term fire resistance structure. Analyzed at the theoretical level, mainly because the air flow with a high flow rate can carry away the combustion heat accumulated in the fire-resistant structure faster and accelerate the outward dissipation of the combustion heat.

[0134] 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 needs of extending the fire resistance duration.

[0135] Now two optional flow rate and flow distribution forms with better effects of extending the fire resistance duration are provided:

[0136] 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.

[0137] When the fire-resistant structure burns, the large-flow air flow will pass through the outer region of the fire-resistant structure with relatively high heat dissipation efficiency at a high speed, taking away a large amount of combustion heat faster and further increasing the dissipation speed 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 is 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.

[0138] 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.

[0139] When the fire-resistant structure burns, the large-flow air flow will pass through the outer ring region of the fire-resistant structure with relatively high heat dissipation efficiency at a high speed, taking away a large amount of combustion heat faster and further increasing the dissipation speed 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 is 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.

[0140] 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.

[0141] At this time, the porosity distribution forms of the cavity flow guiding structure, the intake end flow guiding structure or the burn-resistant structure can be adjusted in terms of structure and parameters to meet the following relational expressions:

[0142] v1 ≥ 1.2v, preferably v1 ≥ 1.5v;

[0143] v3 ≤ 0.8v, preferably v3 ≤ 0.5v;

[0144] v2 ≤ 0.4v, preferably v2 ≤ 0.2v;

[0145] v1 * s1 ≥ 0.5v * s, preferably v1 * s1 ≥ 0.7v * s;

[0146] v3 * s3 ≤ 0.5v * s, preferably v3 * s3 ≤ 0.3v * s;

[0147] v2 * s2 ≤ 0.3v * s, preferably v2 * s2 ≤ 0.1v * s.

[0148] For the cavity flow guiding structure (airflow control method 1):

[0149] Referring to Figure 11 , when the cavity flow guiding structure divides the outer region airflow G11 and the inner region airflow G12 in the cavity 13, the flow velocity of the outer region airflow G11 can be made greater than that of the inner region airflow G12, and / or the flow rate of the outer region airflow G11 can be made greater than that of the inner region airflow G12, so as to meet the aforementioned first flow velocity and flow rate distribution form.

[0150] Referring to Figure 12 , when the cavity flow guiding structure divides the outer ring region airflow G21, the inner ring region airflow G22, and the middle region airflow G23 in the cavity 13, the flow velocities of the outer ring region airflow G21, the middle region airflow G23, and the inner ring region airflow G22 can be distributed from large to small, and / or the flow rates of the outer ring region airflow G21, the middle region airflow G23, and the inner ring region airflow G22 can be distributed from large to small, so as to meet the aforementioned second flow velocity and flow rate distribution form.

[0151] It should be noted that a series of parameters 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, such as the radius, 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.

[0152] For the intake end flow guiding structure (airflow control method 2):

[0153] Referring to Figure 15, when the intake end flow guiding structure divides the outer region air flow G31 and the inner region air flow G32 in the pressure relief intake end 11, it can make the flow velocity of the outer region air flow G31 greater than that of the inner region air flow G32, and / or make the flow rate of the outer region air flow G31 greater than that of the inner region air flow G32, so as to meet the aforementioned first flow velocity and flow rate distribution form;

[0154] For example, the inlet end flow-through 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 larger than the inlet end flow-through area of the inner region of the first circumferential partition 7, so as to achieve that the flow rate of the outer region air flow G31 is greater than that of the inner region air flow G32;

[0155] In addition, the outlet end flow-through 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-through area of the inner region of the first circumferential partition 7, so as to achieve that the flow velocity of the outer region air flow G31 is greater than that of the inner region air flow G32.

[0156] Refer to Figure 16 , when the intake end flow guiding structure divides the outer region air flow G31, the inner layer region air flow G321, and the middle region air flow G322 in the pressure relief intake end 11, it can make the flow velocities of the outer region air flow G31, the middle region air flow G322, and the inner layer region air flow G321 be distributed from large to small, and / or make the flow rates of the outer region air flow G31, the middle region air flow G322, and the inner layer region air flow G321 be distributed from large to small, so as to meet the aforementioned second flow velocity and flow rate distribution form;

[0157] 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 air flow G31, the middle region air flow G322, and the inner layer region air flow G321 are distributed from large to small;

[0158] In addition, the outlet end flow-through 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-through area of the inner region of the second circumferential partition 8, and the outlet end flow-through 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 air flow G31, the middle region air flow G322, and the inner layer region air flow G321 are distributed from large to small.

[0159] Regarding the porosity distribution of the burn-resistant structure (air flow control method three):

[0160] 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.

[0161] 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.

[0162] 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:

[0163]

[0164]

[0165] 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:

[0166]

[0167]

[0168] 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, it is the maximum gap between two parts of an internal cavity that passes through 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.

[0169] 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.

[0170] Multi-layer refractory structure

[0171] Reference Figure 1 and Figure 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.

[0172] 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 burn 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, it can greatly increase the heat dissipation area of the combustion heat, effectively reduce the risk of the combustion-side fire-resistant layer 21a being 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.

[0173] The following provides some embodiments of fire-resistant structure parameters that have been experimentally proven to obtain better fire blocking duration extension effects:

[0174] 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 , 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.

[0175] From the above relationship, it can be seen 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).

[0176] It should be noted that the spacing L has a great influence on the fire resistance performance. When the spacing L is small, since the heat transfer of the fire-resistant layer 21a on the combustion side 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 fire-resistant layer 21a on the combustion side burns for a long time, the temperature on its upstream side is relatively high, which is likely to ignite the combustible gas in the gap between the fire-resistant layer 21a on the combustion side and the first protection-side fire-resistant layer. The combustible gas may continue to burn in the large gap, easily causing a smoldering phenomenon. The combustion heat in the gap is more difficult to dissipate outward, and most of it is transferred upstream, also increasing the risk of fire resistance failure.

[0177] Therefore, in order to obtain a better fire resistance effect, preferably, the size of the spacing L is limited by the above relationship. The above relationship is related to the type of gas and is obtained by fitting the experimental results in the following table:

[0178]

[0179] 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:

[0180] For Class IIA combustible gas, L ≤ 6 mm, preferably, 2 mm ≤ L ≤ 4 mm;

[0181] For Class IIB3 combustible gas, L ≤ 4 mm, preferably, 1 mm ≤ L ≤ 2 mm.

[0182] 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 air flow in the interval area between the fire-resistant layer 21a on the combustion side 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 fire-resistant layer 21a on the combustion side and the first protection-side fire-resistant layer.

[0183] 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 4.58 δ.

[0184] In a specific embodiment, in order to reduce the flow resistance, it is necessary to satisfy: T < 6.28e 4.58δ .

[0185] In a specific embodiment, the thickness of the protection-side fire-resistant layer 21b is T2, satisfying: T2 ≤ 1.57e 4.58δ .

[0186] 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.

[0187] In a specific embodiment, the thickness of the combustion-side fire-resistant layer 21a is T1, and it is satisfied that T1 ≥ T2.

[0188] In a specific embodiment, when the long-time fire-resistant 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.

[0189] In a specific embodiment, the gap value of the combustion-side fire-resistant layer 21a is h1, and the gap value of the protection-side fire-resistant layer 21b is h2, and it is satisfied that h1 ≤ h2.

[0190] In a specific embodiment, h1 ≤ MESG, and preferably, h1 ≤ 0.5 MESG.

[0191] In a specific embodiment, h2 ≤ MESG, and preferably, h2 ≤ 0.8 MESG.

[0192] In a specific embodiment, the gap of the combustion-side fire-resistant layer 21a is axially deflected relative to the combustion-side fire-resistant layer 21a, and the deflection angle is α, and it is satisfied that T1 * tanα ≥ h1.

[0193] In a specific embodiment, the flow area of each fire-resistant layer 2 is not less than the flow area of the pressure relief air inlet end 11.

[0194] Axial heat insulation of refractory structure (heat insulation support structure)

[0195] Referring to Figure 1 and Figure 2 , the long-time fire-resistant structure may include a heat insulation support structure 3 disposed between two adjacent fire-resistant layers 2, and the heat insulation support structure 3 is in contact with the two adjacent fire-resistant layers 2.

[0196] 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 fire-resistant layers 2, thereby reducing and delaying 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 fire-resistant layer 2 is deformed by heat, it can support the deformed fire-resistant layer 2 to prevent it from directly contacting the upstream fire-resistant layer 2 too quickly, 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 fire-resistant structure.

[0197] 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 fire-resistant layer 2, so as to effectively prevent the downstream fire-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.

[0198] 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.

[0199] In a specific embodiment, is not greater than 3%, preferably, is not greater than 1%.

[0200] 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.

[0201] 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.

[0202] 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.

[0203] To improve the heat insulation effect, it can also be achieved by increasing the thickness of the heat insulation support structure 3.

[0204] 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 part 32a and a heat insulation support protruding part 32b protruding from the heat insulation support body part 32a along the axial direction, that is, the total thickness of the heat insulation support structure 3 is increased by setting a heightening structure (heat insulation support protruding part 32b) in the integrated heat insulation support structure 3.

[0205] In addition, the heat insulation 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 insulation support structure 3, the heat insulation support structure 3 will not deform or deform excessively and lose its good support strength.

[0206] In a specific embodiment, the heat-resistant temperature of the heat insulation support structure 3 is not less than 1000 °C.

[0207] In a specific embodiment, the linear change rate of the heat insulation support structure 3 is not greater than 10%, preferably, the linear change rate of the heat insulation support structure 3 is not greater than 5%, so that the heat insulation support structure 3 can have no obvious deformation when heated for a long time.

[0208] Furthermore, the present invention does not limit the internal structure of the heat insulation support structure 3. For example, the heat insulation support structure 3 can be a solid heat insulation support structure, a porous heat insulation support structure with a porous structure, and a hollow heat insulation support structure with a hollow cavity, etc.

[0209] Radial heat insulation of refractory structure

[0210] 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 , and 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 , and 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.

[0211] Referring 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, and thus the inner area of the fire-resistant layer can be set as a closed heat insulation area, while the outer ring area 22a of the fire-resistant layer can allow the pressure relief air flow to circulate.

[0212] Since the inner area of the fire-resistant layer is closed and has a heat insulation 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 resistance duration.

[0213] In a specific embodiment, referring 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 arranged on the first closed heat-insulating disc 23a. A plurality of first fitting openings are formed at intervals along the circumferential direction 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.

[0214] With such an arrangement, the plurality of first fire-blocking discs 23b are all available for the pressure-relief air flow to pass through, thus 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. 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 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.

[0215] Refer 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.

[0216] 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 burning-through phenomena. 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.

[0217] In a specific embodiment, refer 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 arranged on the second closed heat-insulating disc 24a. A plurality of second fitting openings are formed at intervals along the circumferential direction 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.

[0218] With such an arrangement, both the third fire-blocking plate 24c and the multiple second fire-blocking plates 24b allow the pressure-relief air flow to pass through, thereby ensuring the flowability of the intermediate region 22c and the outer ring region 22a of the fire-resistant layer. In the second closed heat-insulating plate 24a, except for the regions where the third fire-blocking plate 24c and the multiple second fire-blocking plates 24b are embedded, the remaining regions do not allow the pressure-relief air flow to pass through and have a heat-insulating function at the same time. It can not only effectively slow down the transfer of the combustion heat in the outer ring region 22a of the fire-resistant layer to the intermediate region 22c of the fire-resistant layer, but also slow down the heat transfer between the multiple second fire-blocking plates 24b, causing more combustion heat to dissipate to the outside atmosphere.

[0219] 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 plate 25c that are nested in sequence from the outside to the inside. Among them, the outer ring region 22a of the fire-resistant layer is provided on the fire-blocking ring 25a, the inner ring region 22b of the fire-resistant layer is provided on the closed heat-insulating ring 25b, and the intermediate region 22c of the fire-resistant layer is provided on the fourth fire-blocking plate 25c.

[0220] With such an arrangement, both the fire-blocking ring 25a and the fourth fire-blocking plate 25c allow the pressure-relief air flow to pass through, thereby ensuring the flowability of the outer ring region 22a and the intermediate region 22c of the fire-resistant layer. The closed heat-insulating ring 25b does not allow the pressure-relief air flow to pass through and has a heat-insulating function at the same time. It can effectively slow down the transfer of the combustion heat in the outer ring region 22a of the fire-resistant layer to the intermediate region 22c of the fire-resistant layer, causing more combustion heat to dissipate to the outside atmosphere.

[0221] It should be noted that the above-mentioned first closed heat-insulating plate 23a, second closed heat-insulating plate 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 materials with low thermal conductivity to achieve good heat-insulating performance.

[0222] Stacked porous refractory layer

[0223] The fire-resistant layer 2 can adopt structures such as a corrugated plate fire-blocking plate with a porous structure, a sintered porous fire-resistant layer, and a stacked porous fire-resistant layer. In this embodiment, specifically for the stacked porous fire-resistant layer, some specific embodiments that can obtain better effects of extending the fire-blocking duration are provided.

[0224] In a specific embodiment, referring to Figure 27 , the stacked porous fire-resistant layer may include a first layer shell 26a and a plurality of stacked particles 26b stacked inside the first layer shell 26a.

[0225] Both the first-layer 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 shell through-holes are provided on both the upstream side wall and the downstream side wall of the first-layer shell 26a. The pressure-relief air flow can flow into the refractory layer through the plurality of first-layer 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 refractory layer through the plurality of first-layer shell through-holes on the downstream side wall. To ensure that the stacked particles 26b do not fall out of the first-layer shell through-holes, the diameter of the first-layer shell through-holes should be smaller than the diameter of the stacked particles 26b.

[0226] 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 the failure of flame arrest. Therefore, the thermal deformation of the stacked particles 26b should be minimized as much as possible.

[0227] For example, the distance between the upstream inner side wall and the downstream inner side wall of the first-layer shell 26a can be made the same as the total stacking thickness of the multiple stacked particles 26b along the axial direction of the stacked porous refractory 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 flame arrest failure.

[0228] In addition, the diameter d1 of the stacked particles 26b and the total stacking thickness T3 of the multiple stacked particles 26b along the axial direction of the stacked porous refractory layer are related to the gas explosion grade. To achieve a better effect of extending the flame arrest duration, d1 and T3 can be set according to the following relational formula, and the relational formula is as follows:

[0229] When the pressure-relief air flow is Class IIA gas, 1 ≤ [0.068ln(d1) + 0.31] * d1 / [(0.69 - 0.068ln(d1))] ≤ 1.5;

[0230] 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;

[0231] 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.

[0232] If the combustible gas is a mixed gas, its MESG value can be calculated based on its different gas components, or it can be simplified to refer to the MESG value of a typical gas corresponding to the 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.

[0233] For the stacked porous fire-resistant layer, the pressure-relief air flow needs to pass through the gaps between the particles. When the particle size of the stacked particles 26b is larger, the gaps between the particle stacks are also larger. However, too large gaps between the particle stacks will cause the flame to burn in the gaps, leading to flashback and failure of fire prevention.

[0234] The above relationship limits the equivalent pore size represented by the gap value formed between the stacked particles 26b, enabling the flame to be quenched between the pores, thereby achieving fire prevention. At the same time, to ensure the flow performance, the total stacked thickness T3 is limited.

[0235] 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.

[0236] 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 having a certain flowability. 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. To ensure that the lightweight spheres do not fall out through the second shell through-holes, the diameter of the second shell through-holes should be smaller than the diameter of the lightweight spheres.

[0237] 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 prevention performance.

[0238] Convex design of combustion side refractory layer

[0239] By setting at least a part of the downstream side surface of the combustion-side fire-resistant layer 21a to protrude downstream, 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 prevention duration of the combustion-side fire-resistant layer 21a.

[0240] For example, the downstream side of the fire-resistant layer 21a on the combustion side 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.

[0241] In other words, the specific form of the convex area on the downstream side of the fire-resistant layer 21a on the combustion side in this embodiment is not limited, as long as it is beneficial to improving the heat dissipation effect.

[0242] In a specific embodiment, referring to Figure 28 , the fire-resistant layer 21a on the combustion side 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 fire-resistant layer 21a on the combustion side, the fire-resistant layer convex portion 27b can improve the heat dissipation effect. In the upstream part of the fire-resistant layer 21a on the combustion side, the shape of the fire-resistant layer disc portion 27a is the same as that of the fire-resistant layer 21b on the protection side. The upstream side surfaces of both the fire-resistant layer disc portion 27a and the fire-resistant layer 21b on the protection side are 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 fire-resistant layer 21b on the protection side 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 range.

[0243] In addition, the radian corresponding to the local spherical surface is β, which is related to the structural dimensions of the fire-resistant layer 21a on the combustion side and the fire resistance and burning resistance level.

[0244] The fire resistance and burning resistance level is classified according to ISO16852. 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.

[0245] In order to better represent the relationship between β and the structural dimensions of the fire-resistant layer 21a on the combustion side 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:

[0246] β = 3.78ε -0.8 arctan(T4 / R1);

[0247] 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.

[0248] 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.

[0249] High-temperature resistant coating

[0250] To improve the fire resistance and burning resistance performance, a high-temperature resistant coating can be coated at least on the downstream side surface of the fire-resistant layer 2 itself. Preferably, a high-temperature resistant coating that has no performance damage under long-term combustion conditions of not less than 2 hours and above 450°C is coated.

[0251] 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 resistance and burning resistance performance of the fire-resistant layer 2 with a larger area.

[0252] 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 coated. For example, the reflectivity of the high-temperature resistant coating is not less than 70%, and preferably, the reflectivity is not less than 90%.

[0253] In a specific embodiment, the thickness of the high-temperature resistant coating coated on the combustion-side fire-resistant layer 21a is 200 μm to 500 μm, and preferably, the thickness is 300 μm to 500 μm.

[0254] In a specific embodiment, for the protection-side fire-resistant layer 21b, a high-temperature resistant coating with a low thermal conductivity is preferably coated. For example, the thermal conductivity of the high-temperature resistant coating is not greater than 0.2 W / (m·K).

[0255] In a specific embodiment, the thickness of the high-temperature resistant coating coated on the protection-side fire-resistant layer 21b is 20 μm to 50 μm.

[0256] 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:

[0257]

[0258] T0≥3.14e 1.31MESG+1.88 ;

[0259] Among them, MESG is the maximum experimental safe gap, i.e., MESG (maximum experimental safe gap). For all concentrations of the gas or vapor to be measured, 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 in accordance with IEC60079-20-1:2010.

[0260] It should be noted that the characteristic value h of the flame-retarding gap of the flame-resistant layer 2 g is closely related to the flame-retarding and heat-resistant performance. When the characteristic value h of the flame-retarding gap g is relatively large, the flow rate of the pressure-relieving air flow that can pass through is relatively large, and its combustion heat is high, so that more heat per unit area is transferred to the downstream flame-resistant layer 2, thus affecting the flame-retarding and heat-resistant effect; while when the characteristic value h of the flame-retarding gap g is relatively small, although the flow rate of the pressure-relieving air flow that can pass through is relatively small and its combustion heat is low, the flow performance is poor. Therefore, in actual applications, in order to obtain better flow performance, a larger area of the flame-resistant layer is required. Along with the increase in the area of the flame-resistant layer, the total combustion heat does not decrease, and the heat in the middle region of the flame-resistant layer is more difficult to dissipate due to the increase in the area of the flame-resistant layer, thus affecting the flame-retarding and heat-resistant performance.

[0261] In the case of coating with a high-temperature resistant coating, the characteristic value of the flame-retarding gap of the flame-resistant layer 2 is h g changes. Therefore, preferably, through the above relationship, the characteristic value of the flame-retarding gap is h g and the thickness T of the high-temperature resistant coating that affects the characteristic value of the flame-retarding gap is h g etc. are limited. t

[0262] Long-time fire resistance working condition not less than 2 hours

[0263] At present, since it is difficult to meet the nitrogen sealing amount in some domestic storage tanks or tank farms, the gas phase space will be Zone 1. API2000 recommends that for storage tanks with a gas phase space of Zone 1 after setting nitrogen sealing (or other gas seals), the flame arrester or flame arrestor breather valve on the storage tank should be a long-time flame-retarding and heat-resistant atmospheric deflagration type flame arrester, and the flame-retarding and heat-resistant duration should not be less than 2 hours. However, the existing flame arresters or flame arrestor breather valves are difficult to meet the requirement of a flame-retarding and heat-resistant duration of not less than 2 hours.

[0264] Based on the foregoing concept, the present invention further provides embodiments of a long-time flame-retarding structure with a flame-retarding duration of not less than 2 hours, and sets multiple comparative examples for comparison to better reflect the improvement effect of the present invention on the flame-retarding duration.

[0265] ​In the experimental tests of multiple embodiments and comparative examples, the pipe diameter specification of the pressure relief air inlet end 11 is DN100. The experimental test medium uses a mixture of n-hexane and air recommended by ISO16852, and 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 time required for the upstream side to rise by 20 °C, and whether the fire can be blocked after burning for 2 hours, etc.

[0266] Example 1:

[0267] Referring to Figure 8 and Figure 18 , the specific structural parameters in the long-term fire-blocking structure are as follows:

[0268] 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;

[0269] 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;

[0270] 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;

[0271] 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;

[0272] 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;

[0273] 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.

[0274] Example 2:

[0275] Referring to Figure 4 , Figure 5 and Figure 18 , the specific structural parameters in the long-term fire-blocking structure are as follows:

[0276] 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;

[0277] 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 this middle circular area;

[0278] 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;

[0279] 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;

[0280] 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.

[0281] Example 3:

[0282] Refer to Figure 10 and Figure 18 , and the specific structural parameters in the long-time firestop structure are as follows:

[0283] 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;

[0284] The middle flow guide member 4 is made of a metal circular plate, with a diameter of 0.8d, and is spaced 0.25d from the upstream side wall of the cavity 13;

[0285] The first annular flow guide member 5 is made of a metal annular plate, with an inner diameter and an outer diameter of d and 1.4d respectively, and is axially spaced 0.15d from the middle flow guide member 4;

[0286] The second annular flow guide member 6 is made of a metal annular plate, with an inner diameter and an outer diameter of 1.3d and 1.6d respectively, and is axially spaced 0.15d from the first annular flow guide member 5;

[0287] 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;

[0288] 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;

[0289] The heat-insulating support structure 3 is made of high-temperature-resistant metal wire with a cross-sectional diameter of 2 mm. The heat-insulating 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.

[0290] Example 4:

[0291] Referring to Figure 24 and Figure 18 , the specific structural parameters in the long-time fire-blocking structure are as follows:

[0292] 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;

[0293] The middle flow guide member 4 is made of a metal circular plate with a diameter of 0.8d, and is spaced 0.25d from the upstream side wall of the cavity 13;

[0294] 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 0.25d from the middle flow guide member 4;

[0295] The protection-side fire-resistant layer 21b includes a corrugated plate fire-blocking disc, a closed heat-insulating metal ring, and a corrugated plate fire-blocking 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-blocking disc, its diameter is 0.8d, its thickness is 15 mm, and the fire-blocking gap value is 0.45 mm; for the corrugated plate fire-blocking ring, its inner and outer diameters are 1.3d and 1.6d respectively, its thickness is 15 mm, and the fire-blocking gap value is 0.45 mm;

[0296] The combustion-side fire-resistant layer 21a includes a corrugated plate fire-blocking disc, a closed heat-insulating metal ring, and a corrugated plate fire-blocking 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-blocking disc, its diameter is 0.8d, its thickness is 15 mm, and the fire-blocking gap value is 0.45 mm; for the corrugated plate fire-blocking ring, its inner and outer diameters are 1.3d and 1.6d respectively, its thickness is 15 mm, and the fire-blocking gap value is 0.45 mm;

[0297] The heat-insulating support structure 3 is made of high-temperature-resistant metal wire with a cross-sectional diameter of 2 mm. The heat-insulating 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.

[0298] Example 5:

[0299] Referring to Figure 9 and Figure 18 , the specific structural parameters in the long-time fire-blocking structure are as follows:

[0300] The cavity 13 adopts 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;

[0301] 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;

[0302] 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;

[0303] Both of the two protective side fire-resistant layers 21b adopt corrugated plate fire-resistant discs, each with a diameter of 2d, a thickness of 15 mm, and a fire-resistant gap value of 0.45 mm;

[0304] 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;

[0305] Both of the two heat insulation support structures 3 adopt high-temperature resistant metal wires, each with a cross-sectional diameter of 2 mm. Both of the two heat insulation support structures 3 are arranged in a triangular shape, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion side fire-resistant layer 21a.

[0306] Example 6:

[0307] Refer to Figure 8 and Figure 19 , the specific structural parameters in the long-term fire-resistant structure are as follows:

[0308] The cavity 13 adopts 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;

[0309] 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;

[0310] 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;

[0311] 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;

[0312] 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;

[0313] The heat insulation support structure 3 adopts 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 they are all arranged in a triangular shape. The diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion side fire-resistant layer 21a.

[0314] Example 7:

[0315] Referring to Figure 8 and Figure 21 , the specific structural parameters in the long-time fire-resistant structure are as follows:

[0316] 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;

[0317] 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;

[0318] 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;

[0319] 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;

[0320] 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;

[0321] 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.

[0322] Example 8:

[0323] 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:

[0324] 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;

[0325] A first flange is provided at the upstream end of the pressure relief air inlet end 11;

[0326] 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 diverting; 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;

[0327] The first annular flow guide member 5 is made of a metal annular plate with an inner diameter and an outer diameter of 1.3d and 1.6d respectively, and is axially spaced from the middle flow guide member 4 by 0.25d;

[0328] The fire-resistant layer 21b on the protection side adopts a corrugated plate firestop disk with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0329] The fire-resistant layer 21a on the combustion side adopts a corrugated plate firestop disk with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0330] The heat-insulating support structure 3 adopts high-temperature-resistant metal wires with a cross-sectional diameter of 2 mm. The heat-insulating 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.

[0331] Example 9:

[0332] 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:

[0333] 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;

[0334] A second flange is provided at the upstream end of the pressure relief air inlet end 11;

[0335] The middle flow guide member 4 serves as the pressure relief valve disk 43 of the breather valve. The pressure relief valve disk 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 disk 43 can switch the on-off state between the cavity 13 and the pressure relief air inlet end 11. When the pressure relief valve disk 43 moves downstream to open and the cavity 13 is communicated with the pressure relief air inlet end 11, the pressure relief valve disk 43 plays a role in guiding and distributing the flow; among them, the diameter of the pressure relief valve disk 43 is d, and it is axially spaced from the upstream side wall of the cavity 13 by 0.25d;

[0336] The first annular flow guide member 5 is made of a metal annular plate with an inner diameter and an outer diameter of 1.3d and 1.6d respectively, and is axially spaced from the middle flow guide member 4 by 0.25d;

[0337] The fire-resistant layer 21b on the protection side adopts a corrugated plate firestop disk with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0338] The fire-resistant layer 21a on the combustion side adopts a corrugated plate firestop disk with a diameter of 2d, a thickness of 15 mm, and a firestop gap value of 0.45 mm;

[0339] The heat insulation support structure 3 uses 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 combustion-side fire-resistant layer 21a.

[0340] Comparative Example 1:

[0341] 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.

[0342] 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.

[0343] Comparative Example 2:

[0344] 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.

[0345] The following table shows the comparison of the experimental data of Embodiments 1-9 and Comparative Examples 1-2:

[0346]

[0347]

[0348] As can be seen from the above table, the long-time fire-blocking structure of the present invention, when having a multi-layer fire-resistant structure in different forms, a heat insulation support structure 3, and adopting the active flow splitting technology, 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.

[0349] 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 these features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0350] In the present invention, unless otherwise clearly specified or limited, terms such as "installed", "connected", "coupled", "fixed", etc. shall be construed 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 communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention may be understood according to specific circumstances.

[0351] In the description of this specification, the description with reference to terms such as "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 representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0352] 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 a convex design, 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 outlet end (12), and a cavity (13) connecting the pressure-relief air inlet end (11) and the pressure-relief air outlet end (12); A fire-resistant structure, arranged at the pressure-relief air outlet end (12), the fire-resistant structure includes a plurality of fire-resistant layers (2) arranged at intervals along the axial direction of the pressure-relief air outlet end (12), the fire-resistant layer (2) located at the most downstream forms a combustion-side fire-resistant layer (21a), and the fire-resistant layer (2) located upstream of the combustion-side fire-resistant layer (21a) forms a protection-side fire-resistant layer (21b), at least part of the downstream side surface of the combustion-side fire-resistant layer (21a) protrudes downward; and A flow guiding structure, arranged in the housing (1) and upstream of the fire-resistant structure, and used for dividing the pressure-relief air flow in the housing (1) into multiple regional air flows flowing towards different regions of the fire-resistant structure.

2. The long-time fire-resistant structure with a convex design according to claim 1, Characterized in that, The downstream side surface of the combustion-side fire-resistant layer (21a) forms a fire-resistant layer curved surface.

3. The long-time fire-resistant structure with a convex design according to claim 2, Characterized in that, The fire-resistant layer curved surface forms a variable-curvature curved surface or a constant-curvature curved surface with a single protruding position.

4. The long-time fire-resistant structure with a convex design according to claim 2, Characterized in that, The fire-resistant layer curved surface forms a local spherical surface.

5. The long-time fire-resistant structure with a convex design according to claim 4, Characterized in that, The combustion-side fire-resistant layer (21a) includes a fire-resistant layer disc part (27a) and a fire-resistant layer convex part (27b) connected to the downstream side of the fire-resistant layer disc part (27a), and the downstream side surface of the fire-resistant layer convex part (27b) is a local spherical surface protruding downward.

6. The long-time fire-resistant structure with a convex design according to claim 5, Characterized in that, The radius of the disk part (27a) of the fire-resistant layer is R1 and the thickness is T4. The radian corresponding to the partial spherical surface is β, and it satisfies: β = 3.78ε -0.8 arctan(T4 / R1); where ε is the MESG value of typical representative combustible gases such as n-hexane, ethylene and hydrogen, and MESG is the maximum experimental safe gap.

7. The long-time fire-resistant structure with a convex design according to any one of claims 1 to 6, Characterized in that, The flow guiding structure includes: A cavity flow guiding structure, arranged in the cavity (13), and used for dividing the pressure-relief air flow flowing into the cavity (13) 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, and making the flow rate of the outer region air flow (G11) greater than the flow rate of the inner region air flow (G12), and / or making the flow rate of the outer region air flow (G11) greater than the flow rate of the inner region air flow (G12).

8. The long-time fire-resistant structure with a convex design according to any one of claims 1 to 6, Characterized in that, The flow guiding structure includes: The cavity flow guiding structure is arranged inside the cavity (13) and is used to divide the pressure relief air flow flowing into the cavity (13) into an outer ring area air flow (G21), an inner ring area air flow (G22), and a middle area air flow (G23) that are sequentially distributed from the outside to the inside in the cavity (13), and to make the flow rates of the outer ring area air flow (G21), the middle area air flow (G23), and the inner ring area air flow (G22) decrease from large to small, and / or to make the flow rates of the outer ring area air flow (G21), the middle area air flow (G23), and the inner ring area air flow (G22) decrease from large to small.

9. The long-time fire resistance structure with a convex design according to any one of claims 1 to 6, characterized in that the flow guiding structure includes: An air inlet end flow guiding structure is arranged inside the pressure relief air inlet end (11) and is used to divide the pressure relief air flow flowing into the pressure relief air inlet end (11) into an outer layer area air flow (G31) and an inner area air flow (G32) that flow in the outer layer area and the inner area of the pressure relief air inlet end (11) respectively, and to make the flow rate of the outer layer area air flow (G31) greater than the flow rate of the inner area air flow (G32), and / or to make the flow rate of the outer layer area air flow (G31) greater than the flow rate of the inner area air flow (G32).

10. The long-time fire resistance structure with a convex design according to any one of claims 1 to 6, characterized in that the flow guiding structure includes: An air inlet end flow guiding structure is arranged inside the pressure relief air inlet end (11) and is used to divide the pressure relief air flow flowing into the pressure relief air inlet end (11) into an outer layer area air flow (G31), an inner layer area air flow (G321), and a middle area air flow (G322) that flow in the outer layer area, the inner layer area, and the middle area of the pressure relief air inlet end (11) respectively, and to make the flow rates of the outer layer area air flow (G31), the middle area air flow (G322), and the inner layer area air flow (G321) decrease from large to small, and / or to make the flow rates of the outer layer area air flow (G31), the middle area air flow (G322), and the inner layer area air flow (G321) decrease from large to small.

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