Long-time fire retardant structure with axial heat insulation function

Abstract

The invention relates to the field of flame arresters, and discloses a long-time flame arresting structure with an axial heat insulation function, which comprises a shell provided with a pressure relief air inlet end, a pressure relief air outlet end and a cavity; the burning-resistant structure is arranged at the pressure relief exhaust end and 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 is a burning side burning-resistant layer, and the burning-resistant layer located at the upstream of the burning side burning-resistant layer is a protection side burning-resistant layer; the heat insulation supporting structure is arranged between the two adjacent burning-resistant layers and is in contact with the two adjacent burning-resistant layers; 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. The long-time fire-retardant structure can provide long-time burning-resistant protection when accidents such as fire break out at the pressure relief position of the storage tank of the petrochemical device occur, so that further expansion of the accidents can be prevented, and more preparation time is reserved for emergency rescue.

Description

Technical Field

[0001] The present invention belongs to the technical field of flame arresters, and particularly relates to a long-time flame-retarding structure with axial heat insulation function. Background Art

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

[0003] However, most of the combustible gases exhaled from the storage tank are premixed combustible gases with high calorific values. Existing pipe-end flame arresters or flame-retarding breather valves generally have problems such as inability to withstand burning for a long time, resulting in the inability to provide long-time burning resistance protection before long-time burning at the pipe end and the effective implementation of emergency rescue measures, thus causing the accident to further expand. Summary of the Invention

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

[0005] To achieve the above purpose, the present invention provides a long-time flame-retarding structure with axial heat insulation function, which includes:

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

[0007] A burning-resistant structure, arranged at the pressure relief air outlet end, the burning-resistant structure includes a plurality of burning-resistant layers arranged at intervals along the axis of the pressure relief air outlet end, the burning-resistant layer located at the most downstream forms a burning-side burning-resistant layer, and the burning-resistant layer located upstream of the burning-side burning-resistant layer forms a protection-side burning-resistant layer;

[0008] An insulating support structure, arranged between two adjacent burning-resistant layers and in contact with the two adjacent burning-resistant layers; and

[0009] A flow guiding structure, arranged in the housing and upstream of the burning-resistant 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-resistant structure.

[0010] In some embodiments, the proportion of the total contact area of the heat insulation support structure with two adjacent refractory layers to the cross-sectional area of the refractory layer is The thermal conductivity of the heat insulation support structure 3 is λ, satisfying:

[0011]

[0012] In some embodiments, not greater than 3%, preferably, not greater than 1%.

[0013] In some embodiments, the refractory layer on the protection side closest to the combustion-side refractory layer is the first protection-side refractory layer. The distance between the combustion-side refractory layer and the first protection-side refractory layer is L, and the diameter of the first protection-side refractory layer is D2, satisfying: L = 3.31 + 2.615MESG - 0.012D 2 , where MESG is the maximum experimental safe gap.

[0014] In some embodiments, the heat-resistant temperature of the heat insulation support structure is not less than 1000 °C; and / or, the linear change rate of the heat insulation support structure is not greater than 10%, preferably, the linear change rate of the heat insulation support structure is not greater than 5%.

[0015] In some embodiments, the heat insulation support structure is a multi-layer heat insulation support structure, and the multi-layer heat insulation support structure includes a plurality of heat insulation support units stacked in sequence along the axial direction; or, the multi-layer heat insulation support structure includes a heat insulation support body portion and a heat insulation support protrusion portion protruding from the heat insulation support body portion along the axial direction.

[0016] In some embodiments, the heat insulation support structure includes a solid heat insulation support structure, a porous heat insulation support structure having a porous structure, and a hollow heat insulation support structure having a hollow cavity.

[0017] In some embodiments, the heat insulation support structure forms a point contact, a line contact, or a surface contact with the refractory layer.

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

[0019] A cavity flow guiding structure, which is arranged in the cavity and is used for dividing 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 making the flow rate of the outer region airflow greater than that of the inner region airflow, and / or making the flow rate of the outer region airflow greater than that of the inner region airflow.

[0020] In some embodiments, the flow guiding structure includes:

[0021] A cavity flow guiding structure is arranged inside the cavity and is used for dividing the pressure relief air flow flowing into the cavity into an outer ring area air flow, an inner ring area air flow, and a middle area air flow that are sequentially distributed from the outside to the inside in the cavity, and enabling the flow velocity of the outer ring area air flow, the flow velocity of the middle area air flow, and the flow velocity of the inner ring area air flow to be distributed from large to small, and / or enabling the flow rate of the outer ring area air flow, the flow rate of the middle area air flow, and the flow rate of the inner ring area air flow to be distributed from large to small.

[0022] In some embodiments, the flow guiding structure includes:

[0023] An air inlet end flow guiding structure is arranged inside the pressure relief air inlet end and is used for dividing the pressure relief air flow flowing into the pressure relief air inlet end into an outer layer area air flow and an inner area air flow that respectively flow in the outer layer area and the inner area in the pressure relief air inlet end, and enabling the flow velocity of the outer layer area air flow to be greater than the flow velocity of the inner area air flow, and / or enabling the flow rate of the outer layer area air flow to be greater than the flow rate of the inner area air flow.

[0024] In some embodiments, the flow guiding structure includes:

[0025] An air inlet end flow guiding structure is arranged inside the pressure relief air inlet end and is used for dividing the pressure relief air flow flowing into the pressure relief air inlet end into an outer layer area air flow, an inner layer area air flow, and a middle area air flow that respectively flow in the outer layer area, the inner layer area, and the middle area in the pressure relief air inlet end, and enabling the flow velocity of the outer layer area air flow, the flow velocity of the middle area air flow, and the flow velocity of the inner layer area air flow to be distributed from large to small, and / or enabling the flow rate of the outer layer area air flow, the flow rate of the middle area air flow, and the flow rate of the inner layer area air flow to be distributed from large to small.

[0026] Through the above technical solution, when the combustible pressure relief air flow continuously discharges through the pressure relief exhaust end and is ignited on the downstream side of the combustion side fire-resistant layer, the combustion side fire-resistant layer will be burned for a long time. At this time, since there is at least one protective side fire-resistant layer provided upstream of the combustion side fire-resistant layer, the heat dissipation area of the combustion heat can be greatly increased, the risk of the combustion side fire-resistant layer being burned through due to heat accumulation can be effectively reduced, and even if the combustion side fire-resistant layer is burned through, the protective side fire-resistant layer can also take over to play a fire-blocking role.

[0027] In addition, the heat insulation support structure has a heat insulation function and can effectively weaken the thermal radiation and heat conduction between its adjacent two fire-resistant layers, thereby reducing and delaying the transfer of combustion heat to the inside of the housing; at the same time, the heat insulation support structure also has a support function. When the fire-resistant layer downstream of it is deformed by heat, it can support the deformed fire-resistant layer to prevent it from directly contacting the upstream fire-resistant layer too quickly, thereby also slowing down the transfer of combustion heat to the inside of the housing and taking into account the overall structural integrity of the fire-resistant structure.

[0028] Furthermore, the diversion structure can actively divert the pressure-relief airflow flowing into the housing. The multiple diverted regional airflows can flow through different regions of the fire-resistant structure, thereby dispersing the heat in the fire-resistant structure, effectively reducing the risk of flashback and burning through, and effectively extending the fire-blocking duration.

[0029] It can be seen that the long-time fire-blocking structure of the present invention can provide long-time fire-resistant protection when an accident such as a fire occurs at the pressure-relief position of a storage tank in a petrochemical device, thereby preventing the accident from further expanding and leaving more preparation time for emergency rescue.

[0030] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific embodiment part. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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, other drawings can be obtained based on the structures shown in these drawings without creative efforts. In the drawings:

[0032] Figure 1 is a schematic diagram of a long-time fire-blocking structure in a specific embodiment of the present invention;

[0033] Figure 2 is a schematic diagram of another long-time fire-blocking structure in a specific embodiment of the present invention. The long-time fire-blocking structure in the figure is provided with two protective side fire-resistant layers;

[0034] Figure 3 is a schematic diagram of another long-time fire-blocking structure in a specific embodiment of the present invention. The long-time fire-blocking structure in the figure is provided with a middle diverter;

[0035] Figure 4 is a schematic diagram of another long-time fire-blocking structure in a specific embodiment of the present invention. The long-time fire-blocking structure in the figure is provided with a middle diverter, and the middle diverter is a curved plate with a flow-through structure;

[0036] Figure 5 is an axial schematic diagram of a middle diverter in a specific embodiment of the present invention. The middle diverter in the figure includes a middle circular region provided with a flow-through structure;

[0037] Figure 6 is a schematic diagram of a long-time fire-blocking structure applied as a breathing valve in a specific embodiment of the present invention;

[0038] Figure 7Schematic diagram of a long - time flame - arrester structure applied as a breathing valve in a specific embodiment of the present invention;

[0039] Figure 8 Schematic diagram of another long - time flame - arrester structure in a specific embodiment of the present invention. The long - time flame - arrester structure in the figure is provided with a middle flow - guiding member and a first annular flow - guiding member;

[0040] Figure 9 Schematic diagram of another long - time flame - arrester structure in a specific embodiment of the present invention. The long - time flame - arrester structure in the figure is provided with a middle flow - guiding member, a first annular flow - guiding member and two protective side fire - resistant layers;

[0041] Figure 10 Schematic diagram of another long - time flame - arrester structure in a specific embodiment of the present invention. The long - time flame - arrester structure in the figure is provided with a middle flow - guiding member, a first annular flow - guiding member and a second annular flow - guiding member;

[0042] Figure 11 Regional air - flow distribution diagram in the cavity when a long - time flame - arrester structure in a specific embodiment of the present invention is provided with a cavity flow - guiding structure;

[0043] Figure 12 Regional air - flow distribution diagram in the cavity when another long - time flame - arrester structure in a specific embodiment of the present invention is provided with a cavity flow - guiding structure;

[0044] Figure 13 For Figure 3 Schematic diagram of the structural parameters of the long - time flame - arrester structure in;

[0045] Figure 14 Schematic diagram of an air - inlet end flow - guiding structure in a specific embodiment of the present invention;

[0046] Figure 15 Regional air - flow distribution diagram in the cavity when a long - time flame - arrester structure in a specific embodiment of the present invention is provided with an air - inlet end flow - guiding structure;

[0047] Figure 16 Regional air - flow distribution diagram in the cavity when another long - time flame - arrester structure in a specific embodiment of the present invention is provided with an air - inlet end flow - guiding structure;

[0048] Figures 17 to 19 Axial schematic diagram of three optional heat - insulation support structures in a specific embodiment of the present invention;

[0049] Figures 20 to 21 Side - view schematic diagrams of two other optional heat - insulation support structures in a specific embodiment of the present invention;

[0050] Figure 22Schematic diagram of another long - time fire - resistant 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;

[0051] Figure 23 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;

[0052] Figure 24 Schematic diagram of another long - time fire - resistant 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;

[0053] Figure 25 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;

[0054] Figure 26 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;

[0055] Figure 27 Schematic diagram of a stacked porous fire - resistant layer in the specific embodiment of the present invention;

[0056] Figure 28 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;

[0057] Figure 29 Schematic diagram of a fire - blocking structure for comparative experiments in the specific embodiment of the present invention. There is no gap between the combustion - side fire - resistant layer and the protection - side fire - resistant layer of the fire - blocking structure in the figure.

[0058] Explanation of reference numerals

[0059] 1 Housing;

[0060] 11 Pressure - relief air - inlet end, 12 Pressure - relief air - exhaust end, 13 Cavity;

[0061] 2 Fire - resistant layer;

[0062] 21a Combustion - side fire - resistant layer, 21b Protection - side fire - resistant layer;

[0063] 22a Fire - resistant layer outer - ring area, 22b Fire - resistant layer inner - ring area, 22c Fire - resistant layer middle area;

[0064] 23a First closed heat - insulation disc, 23b First fire - blocking disc;

[0065] 24a Second closed heat-insulating disc, 24b Second fire-blocking disc, 24c Third fire-blocking disc;

[0066] 25a Fire-blocking ring, 25b Closed heat-insulating ring, 25c Fourth fire-blocking disc;

[0067] 26a First-layer shell, 26b Stacked particles;

[0068] 27a Burn-resistant layer disc part, 27b Burn-resistant layer convex part;

[0069] 3 Heat-insulating support structure;

[0070] 31 Heat-insulating support unit;

[0071] 32a Heat-insulating support body part, 32b Heat-insulating support protruding part;

[0072] 4 Middle flow guide;

[0073] 41 Flow-through structure, 42 Bending plate, 43 Pressure relief valve disc;

[0074] 5 First annular flow guide;

[0075] 6 Second annular flow guide;

[0076] 7 First circumferential partition;

[0077] 8 Second circumferential partition;

[0078] G11 Outer region air flow, G12 Inner region air flow;

[0079] G21 Outer ring region air flow, G22 Inner ring region air flow, G23 Middle region air flow;

[0080] G31 Outer layer region air flow, G32 Inner region air flow, G321 Inner layer region air flow, G322 Intermediate region air flow Specific embodiments

[0081] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0082] The following describes a long-time fire-blocking structure according to the present invention with reference to the accompanying drawings.

[0083] Through analysis, when the existing pipe-end flame arrester or flame arrestor breather valve burns for a long time, the combustion heat has three transfer directions. One is to transfer to the inside of the flame arrester through heat conduction and thermal radiation. The second is to be carried away by some combustible gases discharged by the flame arrester. The third is to dissipate to the outside atmosphere through heat conduction, thermal radiation, etc.

[0084] Both the second and third heat transfer directions mentioned above are conducive to preventing the combustion heat from accumulating in the flame arrester, making the flame arrester have a better flame arrest effect. However, the first heat transfer direction is different. The combustion heat transfers to the inside of the flame arrester, which will increase the risk of flashback and burning through of the flame arrester.

[0085] However, the existing pipe-end flame arresters or flame arrestor breathing valves are restricted by their flame arrest structures and internal structure forms. When the flame arrest structure burns, the main direction of the combustion heat transfer is mainly the first one mentioned above. Therefore, the combustion heat will quickly accumulate in the flame arrest structure and will accumulate in the local area (usually the middle area) of the flame arrest structure, and it is easy to have a burning-through phenomenon in this local area.

[0086] To solve the deficiencies of the existing technologies, the long-time flame arrest 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 arrest structure.

[0087] Multiple optional embodiments of the long-time flame arrest structure of the present invention will be provided in the following text. Each embodiment adopts at least one of the above two design directions for design, and can effectively extend the flame arrest duration.

[0088] In each optional embodiment, first refer to Figure 1 , the basic structure of the long-time flame arrest 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 of the combustible gas through the long-time flame arrest structure, the pressure relief air flow sequentially passes through the pressure relief air inlet end 11, the cavity 13, and the pressure relief air outlet end 12 and is discharged. In addition, the fire-resistant structure is arranged at the pressure relief air outlet end 12. In order to ensure that the pressure relief air flow can be discharged from the pressure relief air outlet end 12, structures such as holes and gaps need to be arranged in the fire-resistant structure.

[0089] When there is an ignition source in the outside world and the pressure relief air flow is ignited on the downstream side of the fire-resistant structure, there are the following two working conditions:

[0090] One is the non-long-time fire-resistant working condition. At this time, the pressure relief air flow does not continuously pass through the pressure relief air outlet end 12 for discharge. 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., the inside of the long-time flame arrest structure) of the fire-resistant structure;

[0091] The other is the long-time fire-resistant working condition. At this time, the pressure relief air flow continuously passes through the pressure relief air outlet end 12 for discharge, 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.

[0092] The following is a step-by-step introduction to multiple alternative embodiments that can effectively extend the fire retardant duration:

[0093] Airflow control method 1 (cavity diversion structure)

[0094] Referring to Figure 3 and Figure 11 , the long-time fire retardant structure may include a cavity diversion structure disposed in the cavity 13. Specifically, the cavity diversion structure may include a middle diversion member 4 disposed opposite to the pressure relief air inlet end 11. The pressure relief air flow flowing into the cavity 13 from the pressure relief air inlet end 11 can be divided into an outer region air flow G11 flowing in the outer region of the cavity 13 and an inner region air flow G12 flowing in the inner region of the cavity 13 under the diversion action of the middle diversion member 4.

[0095] Compared with the existing fire arrester under long-time combustion conditions where the combustion heat accumulates in a local area (usually the middle area) of the fire retardant structure, resulting in difficulty in dissipating the combustion heat and even causing the fire retardant structure to be burned through, the long-time fire retardant structure of this embodiment can actively divert the pressure relief air flow flowing into the cavity 13 by setting the middle diversion member 4. The diverted outer region air flow G11 and inner region air flow G12 can disperse the heat in the fire-resistant structure to different regions, thereby effectively reducing the risk of flashback and burn-through phenomena and effectively extending the fire retardant duration.

[0096] Further, referring to Figure 4 and Figure 12 the middle diversion member 4 may be provided with a flow-through structure 41 (such as multiple holes, slits). 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 outer periphery of the middle diversion member 4 and the flow-through structure 41. The pressure relief air flow passing through the outer periphery of the middle diversion member 4 will be divided into two air flows. The air flow in the outer region is the outer ring region air flow G21, and part of the air flow in the inner region will converge with the pressure relief air flow passing through the flow-through structure 41, so that the air flow in the inner region is further formed into two diverted 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.

[0097] In other words, overall, after the pressure relief air flow passes through the middle diversion member 4 provided with the flow-through structure 41, 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 from outside to inside in the region of the cavity 13 downstream of the middle diversion member 4. This flow field form can disperse the heat in the fire-resistant structure to more different regions and further extend the fire retardant duration.

[0098] Referring to Figure 4, to reduce the resistance of the pressure relief air flow, the middle flow guiding member 4 can be set as a bent plate 42 (such as an arc-shaped plate), and the convex surface of the bent plate 42 faces the pressure relief air inlet end 11. In this way, the air flow resistance is smaller when the pressure relief air flow is shunted at the outer periphery of the middle flow guiding member 4, ensuring that the long-time fire resistance structure has a higher pressure relief speed, and at the same time is conducive to taking away the heat in the cavity 13 more quickly.

[0099] In addition to being set as the bent plate 42, the middle flow guiding member 4 can also be set into other streamline shapes, such as conical, spindle-shaped, water droplet-shaped, etc., and the present invention does not limit this.

[0100] Refer to Figure 6 and Figure 7 , when the long-time fire resistance structure is applied to a breathing valve (or an exhalation valve), the middle flow guiding 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 shunting roles.

[0101] Refer to Figure 5 , the flow-through structure 41 can include a plurality of flow-through holes formed in the middle circular area of the middle flow guiding member 4. In addition to roughly limiting the flow range of the air flow G23 in the middle area to the middle cylindrical area of the cavity 13, the flow rate and flow volume of the air flow G23 in the middle area can also be adjusted by designing different aperture sizes and hole distribution densities, etc.

[0102] In a specific embodiment, the total flow-through area of the flow-through structure 41 is not greater than one-third of the flow-through area of the pressure relief air inlet end 11, so as to prevent the problem that the middle area of the fire-resistant structure overheats due to the excessive flow volume of the air flow G23 in the middle area from being effectively solved.

[0103] In a specific embodiment, the area of the axial projection of the middle flow guiding member 4 is not greater than the area of the axial projection of the pressure relief air inlet end 11, preventing the radial dimension of the middle flow guiding member 4 from being too large and affecting the discharge speed of the pressure relief air flow.

[0104] In a specific embodiment, refer to Figure 13 , the diameter of the middle flow guiding member 4 is D1, the distance between the middle flow guiding member 4 and the inner wall of the upstream end of the cavity 13 is H1, the distance between the middle flow guiding 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:

[0105] Among them, e is the natural constant, and its value is approximately 2.718.

[0106] The above relationship mainly optimally limits 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 is 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 fire-resistant structure and a large pressure drop.

[0107] From the perspective of optimizing the flow field distribution, the above relationship designs the range of the diameter D1 of the specific middle flow guide member 4, and respectively limits the range 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 range of the distance H2 between the middle flow guide member 4 and the inner wall of the downstream end of the cavity 13.

[0108] Specifically, the diameter D1 mainly considers that the main air flow of the pressure relief air flow should impact on the middle flow guide member 4, and then flow 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 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.

[0109] The distance H1 mainly considers that the flow 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 to reduce the pressure loss caused by the 90° bend.

[0110] The distance H2 considers that the incoming flow should be fully developed after passing through the middle flow guide member 4, so that the refraction flow generated by the air flow impacting on the inner wall of the downstream end of the cavity 13 forms a good disturbance effect on the air flow, and then forms a relatively uniform flow velocity distribution, which is mainly derived from the fluid mechanics theory, numerical simulation and experimental results.

[0111] Refer to Figure 8 、 Figure 9 and Figure 12, the cavity flow guiding structure may further include a first annular flow guiding member 5 disposed on the downstream side of the middle flow guiding member 4. Wherein, the outer circumferential wall of the first annular flow guiding member 5 is spaced from the inner circumferential wall of the cavity 13. When the middle flow guiding member 4 has already divided the outer region air flow G11 and the inner region air flow G12, the outer region air flow G11 and the inner region air flow G12 can be further divided by the first annular flow guiding member 5 when passing through it. At this time, the air flow of the outer part of the outer region air flow G11 flows downstream through the spaced area between the outer circumferential wall of the first annular flow guiding member 5 and the inner circumferential wall of the cavity 13, and this part of the air flow is the outer ring region air flow G21; while the air flow of the inner part of the outer region air flow G11 and the air flow of the outer part of the inner region air flow G12 are divided when passing through the inner circumferential edge of the first annular flow guiding member 5. The divided air flow close to the inner circumferential edge of the first annular flow guiding member 5 is the inner ring region air flow G22, and the divided air flow far from the inner circumferential edge of the first annular flow guiding member 5 (i.e., the divided air flow flowing in the middle region of the cavity 13) is the middle region air flow G23.

[0112] In other words, overall, after the pressure relief air flow is divided by the middle flow guiding member 4 and the first annular flow guiding member 5, 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 in the region of the cavity 13 downstream of the first annular flow guiding member 5. This flow field form can disperse the heat in the fire-resistant structure to more different regions, further prolonging the fire resistance duration.

[0113] It should be noted that when the middle flow guiding member 4 is provided with a flow-through structure 41 and the cavity flow guiding structure is provided with a first annular flow guiding member 5 at the same time, there will also 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 in the region of the cavity 13 downstream of the first annular flow guiding member 5. This is because the flow-through structure 41 mainly affects the flow rate and / or flow velocity of the middle region air flow G23.

[0114] Refer 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. Wherein, 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 adjust the flow field form of the outer ring region air flow G21, the inner ring region air flow G22, and the middle region air flow G23 to adjust the flow rate and / or flow velocity of the air flow in each region, or can further divide into more strands of region air flow, as evenly as possible to disperse the heat in the fire-resistant structure to achieve an excellent fire resistance duration extension effect.

[0115] Only some optional forms of the cavity diversion structure are listed in the present invention for illustration. It can be understood that other cavity diversion structure forms that can also divide the pressure relief air flow in the cavity 13 into multiple regional air flows should also fall within the scope of the concept of the present invention.

[0116] Airflow control method 2 (inlet end diversion structure)

[0117] Referring to Figure 14 and Figure 15 , the long-time fire-blocking structure may include an intake-end diversion structure provided in the pressure relief intake end 11. Specifically, the intake-end diversion structure may include a first circumferential partition 7, and the outer peripheral wall of the first circumferential partition 7 is spaced from the inner peripheral wall of the pressure relief intake end 11. In this way, the pressure relief air flow flowing into the pressure relief intake end 11 can be divided into an outer-layer regional air flow G31 flowing between the inner peripheral wall of the pressure relief intake end 11 and the outer peripheral wall of the first circumferential partition 7 and an inner-region air flow G32 flowing inside the first circumferential partition 7 under the diversion of the first circumferential partition 7.

[0118] Compared with the existing flame arrester in the long-time combustion condition where the combustion heat accumulates in a local area (usually the middle area) of the fire-blocking structure, resulting in difficulty in dissipating the combustion heat and even causing the fire-blocking structure to be burned through, the long-time fire-blocking structure of this embodiment can actively divide the pressure relief air flow flowing into the pressure relief intake end 11 by providing the first circumferential partition 7. The separated outer-layer regional air flow G31 and inner-region air flow G32 can disperse the heat in the heat-resistant structure to different areas, thereby effectively reducing the risk of flashback and burning through, effectively extending the fire-blocking duration, and achieving long-time fire blocking.

[0119] Further, referring to Figure 14 and Figure 16 , the intake-end diversion structure may further include a second circumferential partition 8 provided inside the first circumferential partition 7, and the second circumferential partition 8 is spaced inside and outside the first circumferential partition 7. At this time, the inner-region air flow G32 can be further divided into an inner-layer regional air flow G321 flowing between the first circumferential partition 7 and the second circumferential partition 8 and an intermediate-region air flow G322 flowing inside the second circumferential partition 8 under the diversion of the second circumferential partition 8.

[0120] In other words, overall, when the pressure relief air flow passes through the intake-end diversion structure provided with the first circumferential partition 7 and the second circumferential partition 8, there will be an outer-layer regional air flow G31, an inner-layer regional air flow G321, and an intermediate-region air flow G322 distributed in sequence from outside to inside in the pressure relief intake end 11. This flow field form can disperse the heat in the heat-resistant structure to more different areas and further extend the fire-blocking duration.

[0121] 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 air flow G31, the inner layer region air flow G321, and the intermediate layer region air flow 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 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.

[0122] 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 inlet end diversion ratio of the annular region between the first circumferential partition 7 and the second circumferential partition 8, and the inlet end diversion ratio of the inner region of the second circumferential partition 8 are a, b, and c respectively.

[0123] Furthermore, the total flow area of the inlet end of the air inlet end flow guiding structure is S0.

[0124] Based on the principle of flow conservation, the following relational expressions are set so that the pressure relief air 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 air flow rate flowing through the outer layer flow-through structure of the fire-resistant structure, the pressure relief air 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 air flow rate flowing through the inner layer flow-through structure of the fire-resistant structure, and the pressure relief air flow rate flowing into the inner region of the second circumferential partition 8 is equal to the pressure relief air flow rate flowing through the intermediate layer flow-through structure of the fire-resistant structure. The specific relational expressions are as follows:

[0125] (S1*σ1) / (S0*a) ≤ 2 / 3;

[0126] (S2*σ2) / (S0*b) ≥ 5;

[0127] 1 ≤ (S3*σ3) / (S0*c) ≤ 3.

[0128] It should be noted that the air inlet end flow guiding 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 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.

[0129] Only some optional forms of the air inlet end flow guiding structure of the present invention are listed for illustration. It can be understood that other forms of the air inlet end flow guiding structure that can also divide the pressure relief air flow in the pressure relief air inlet end 11 into multiple regional air flows should also fall within the concept scope of the present invention.

[0130] In addition to the cavity flow guiding structure and the intake end flow guiding structure provided above, other forms of flow guiding structures can also be arranged in the housing 1. For example, an integral housing flow guiding structure that simultaneously occupies the spaces of the cavity 13 and the pressure relief intake end 11 can also be designed. In other words, the present invention does not limit the specific form of the flow guiding structure arranged in the housing 1, as long as the flow guiding structure is located upstream of the fire-resistant structure and can divide the pressure relief airflow 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.

[0131] Airflow control method 3 (porosity distribution of fire-resistant structure)

[0132] By arranging multiple fire-resistant layer partitions with different porosity rates in the fire-resistant structure, the pressure relief airflow 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 rate of this region can be relatively small to reduce the flow rate passing through this region, thereby reducing the combustion heat in this region.

[0133] Compared with the existing fire arresters in the long-time combustion condition where the combustion heat accumulates in the local area (usually the middle area) of the fire-blocking structure, resulting in the difficulty of dissipating the combustion heat and even causing the fire-blocking structure to be burned through, the long-time fire-blocking structure of this embodiment can actively shunt the pressure relief airflow flowing through the fire-resistant structure by reasonably setting the porosity rates of the multiple fire-resistant layer partitions, prevent the phenomenon of local overheating in the fire-resistant structure, thereby effectively reducing the risk of flashback and burning through, effectively extending the fire resistance duration, and achieving long-time fire blocking.

[0134] 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 airflow flows through the fire-resistant structure, it 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.

[0135] Furthermore, refer to Figure 24 , the fire-resistant layer inner area may include a fire-resistant layer inner ring area 22b and a fire-resistant layer middle area 22c. At this time, the fire-resistant layer outer ring area 22a, the fire-resistant layer inner ring area 22b, and the fire-resistant layer middle area 22c are arranged in sequence from outside to inside. In this way, when the pressure relief airflow flows through the fire-resistant structure, it will be divided into three regional airflows, and the three regional airflows are discharged through the fire-resistant layer outer ring area 22a, the fire-resistant layer inner ring area 22b, and the fire-resistant layer middle area 22c respectively.

[0136] 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 of the fire-resistant layer 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.

[0137] It should be noted that more annular fire-resistant layer partitions can be divided in the fire-resistant structure to divide more regional airflows, so as to disperse the heat in the fire-resistant structure as evenly as possible, so as to achieve an excellent effect of extending the fire resistance duration.

[0138] The specific structural forms of the outer ring region 22a of the fire-resistant layer, the inner region of the fire-resistant layer, the inner ring region 22b of the fire-resistant layer, 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 airflow into multiple regional airflows should also fall within the scope of the concept of the present invention.

[0139] Flow velocity and flow rate distribution form under airflow control

[0140] It has been experimentally proven by the designers of the present invention that when the fire-resistant structure burns, the faster the flow rate of the pressure relief airflow 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 airflow with a high flow rate can carry away the combustion heat accumulated in the fire-resistant structure faster, accelerating the outward dissipation of the combustion heat.

[0141] Therefore, when dividing the pressure relief airflow into multiple regional airflows through the active shunt technology (that is, the aforementioned airflow 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 airflow meet the requirements of extending the fire resistance duration.

[0142] Now two optional flow rate and flow distribution forms with better effects of extending the fire resistance duration are provided:

[0143] The first distribution form is: making the regional airflow with a high flow rate and a large flow pass through the outer region of the fire-resistant structure, and making the regional airflow with a low flow rate and a low flow pass through the inner region of the fire-resistant structure. In particular, there may be no regional airflow passing through the inner region of the fire-resistant structure.

[0144] When the fire-resistant structure burns, the regional air flow with a large flow rate 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 regional air flow with a low flow rate will pass through the inner region (including the middle region) of the fire-resistant structure at a low speed, or there is no regional 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 with a large flow rate, 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 the middle region being burned through.

[0145] The second distribution form is: making the regional air flow with a high flow velocity and a large flow rate pass through the outer ring region of the fire-resistant structure, making the regional air flow with a low flow velocity and a low flow rate pass through the inner ring region of the fire-resistant structure, and making the regional air flow with a medium flow velocity and a medium flow rate pass through the middle region of the fire-resistant structure. And in particular, there may be no regional air flow passing through the inner ring region of the fire-resistant structure.

[0146] When the fire-resistant structure burns, the regional air flow with a large flow rate 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 regional air flow with a medium flow rate 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 with a large flow rate, 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 the middle region being burned through. In addition, the regional air flow with a low flow rate will pass through the inner ring region of the fire-resistant structure at a low speed, or there is no regional air flow passing through the inner ring region of the fire-resistant structure, which is equivalent to making the inner ring region of the fire-resistant structure form a low heat conduction region between the outer ring region and the middle region, thereby weakening the transfer of combustion heat from the outer ring region of the fire-resistant structure to the middle region and further reducing the risk of flashback and being burned through in the middle region of the fire-resistant structure.

[0147] In a specific embodiment, the average velocity of the regional air flow with a high flow velocity and a large flow rate is defined as v1 and the flow area is defined as s1, the average velocity of the regional air flow with a low flow velocity and a low flow rate is defined as v2 and the flow area is defined as s2, the average velocity of the regional air flow with a medium flow velocity and a medium flow rate is defined as v3 and the flow area is defined as s3, and the average flow 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.

[0148] At this time, the porosity distribution form of the cavity diversion structure, the air inlet diversion structure or the fire-resistant structure can be adjusted in terms of structure and parameters to satisfy the following relationship:

[0149] v1≥1.2v, preferably v1≥1.5v;

[0150] v3≤0.8v, preferably v3≤0.5v;

[0151] v2 ≤ 0.4v, preferably v2 ≤ 0.2v;

[0152] v1 * s1 ≥ 0.5v * s, preferably v1 * s1 ≥ 0.7v * s;

[0153] v3 * s3 ≤ 0.5v * s, preferably v3 * s3 ≤ 0.3v * s;

[0154] v2 * s2 ≤ 0.3v * s, preferably v2 * s2 ≤ 0.1v * s.

[0155] For the cavity flow guiding structure (airflow control method 1):

[0156] 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, it can make the flow velocity of the outer region airflow G11 greater than that of the inner region airflow G12, and / or make the flow rate of the outer region airflow G11 greater than that of the inner region airflow G12, so as to meet the aforementioned first flow velocity and flow rate distribution form.

[0157] 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, it can make the flow velocities of the outer ring region airflow G21, the middle region airflow G23, and the inner ring region airflow G22 be distributed from large to small, and / or make the flow rates of the outer ring region airflow G21, the middle region airflow G23, and the inner ring region airflow G22 be distributed from large to small, so as to meet the aforementioned second flow velocity and flow rate distribution form.

[0158] It should be noted that a series of parameters such as the radius of the middle flow guiding member 4, the first annular flow guiding member 5, and the second annular flow guiding member 6 of the cavity flow guiding structure, the spacing in the upstream and downstream directions, and the spacing from the inner peripheral wall of the cavity 13 can be adjusted to meet the actual required flow velocity and flow rate distribution form.

[0159] For the intake end flow guiding structure (airflow control method 2):

[0160] Referring to Figure 15 , when the intake end flow guiding structure divides the outer layer region airflow G31 and the inner region airflow G32 in the pressure relief intake end 11, it can make the flow velocity of the outer layer region airflow G31 greater than that of the inner region airflow G32, and / or make the flow rate of the outer layer region airflow G31 greater than that of the inner region airflow G32, so as to meet the aforementioned first flow velocity and flow rate distribution form;

[0161] For example, the inlet flow area of the annular region between the inner peripheral wall of the pressure relief inlet end 11 and the first circumferential partition 7 can be made larger than the inlet flow 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 the flow rate of the inner region air flow G32;

[0162] In addition, the outlet flow area of the annular region between the inner peripheral wall of the pressure relief inlet end 11 and the first circumferential partition 7 can be made smaller than the outlet flow 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 the flow velocity of the inner region air flow G32.

[0163] Refer to Figure 16 , when the inlet guide structure divides the outer region air flow G31, the inner layer region air flow G321, and the intermediate region air flow G322 in the pressure relief inlet end 11, the flow velocities of the outer region air flow G31, the intermediate region air flow G322, and the inner layer region air flow G321 can be distributed from large to small, and / or the flow rates of the outer region air flow G31, the intermediate region air flow G322, and the inner layer region air flow G321 can be distributed from large to small, so as to meet the aforementioned second flow velocity and flow rate distribution form;

[0164] For example, the inlet shunt ratio of the annular region between the inner peripheral wall of the pressure relief inlet end 11 and the first circumferential partition 7 is a, the inlet shunt ratio of the annular region between the first circumferential partition 7 and the second circumferential partition 8 is b, and the inlet shunt ratio of the inner region of the second circumferential partition 8 is c, satisfying: a > c > b, so as to achieve that the flow rates of the outer region air flow G31, the intermediate region air flow G322, and the inner layer region air flow G321 are distributed from large to small;

[0165] In addition, the outlet flow areas of the annular region between the inner peripheral wall of the pressure relief inlet end 11 and the first circumferential partition 7, the inner region of the second circumferential partition 8, and 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 intermediate region air flow G322, and the inner layer region air flow G321 are distributed from large to small.

[0166] For the porosity distribution of the fire-resistant structure (air flow control method three):

[0167] Refer to Figure 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, so as to meet the aforementioned first flow velocity and flow rate distribution form.

[0168] 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.

[0169] 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:

[0170]

[0171] 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:

[0172]

[0173]

[0174] Among them, ε max is the upper limit value set of the porosity, ε min is the lower limit value set of the 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.

[0175] 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.

[0176] Multi-layered fire-resistant structure

[0177] Referring to Figure 1 and Figure 2 , the fire-resistant structure may include a plurality of fire-resistant layers 2 arranged at intervals in sequence along the axial direction of the pressure relief and exhaust end 12. Among them, the fire-resistant layer 2 located at the most downstream is formed as the 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 the protection-side fire-resistant layer 21b.

[0178] 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 provided 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 to play a fire-blocking role, thereby greatly extending the fire-blocking duration of the fire-resistant structure.

[0179] The following provides some embodiments of the fire-resistant structure parameters that have been experimentally proven and can obtain better fire-blocking duration extension effects:

[0180] In a specific embodiment, the protection-side fire-resistant layer 21b closest to the combustion-side fire-resistant layer 21a is defined as the first protection-side fire-resistant layer. The distance between the combustion-side fire-resistant layer 21a and the first protection-side fire-resistant layer is L, and the diameter of the first protection-side fire-resistant layer is D2, satisfying: L = 3.31 + 2.615MESG - 0.012D 2 , where MESG is the maximum experimental safe gap, MESG (maximum experimental safe gap). For all concentrations of the measured gas or vapor, when the internal mixture is ignited, it is the maximum gap between two parts of an internal cavity 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.

[0181] From the above relational expression, 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).

[0182] It should be noted that the distance L has a greater impact on the fire-blocking and fire-resistant performance. When the distance L is small, since the heat transfer of the combustion-side fire-resistant layer 21a is mainly heat conduction and heat radiation, it will cause the heat transfer to increase geometrically, especially heat radiation, which is inversely proportional to the square of the distance 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-blocking failure; while when the distance L is large, after the combustion-side fire-resistant layer 21a burns for a long time, the temperature on its upstream side is relatively high, and it is easy to ignite the combustible gas in the gap between the combustion-side fire-resistant layer 21a and the first protection-side fire-resistant layer. The combustible gas may continue to burn in the large gap, easily causing a smoldering phenomenon, and the combustion heat in the gap is more difficult to dissipate outward, and most of it is transferred upstream, which also increases the risk of fire-blocking failure.

[0183] Therefore, in order to obtain a better fire-blocking effect, preferably, the size of the distance L is limited by the above relational expression. The above relational expression is related to the gas type and is obtained by fitting the experimental results in the following table:

[0184]

[0185] In a specific embodiment, when the long-time fireproof structure is actually applied, to obtain a better effect of extending the fireproof time, it is necessary to satisfy:

[0186] For Class IIA combustible gas, L ≤ 6 mm, preferably, 2 mm ≤ L ≤ 4 mm;

[0187] For Class IIB3 combustible gas, L ≤ 4 mm, preferably, 1 mm ≤ L ≤ 2 mm.

[0188] By limiting L, it is possible to prevent L from being too large, reducing the risk that the pressure relief airflow in the interval area between the fire-resistant layer 21a on the combustion side and the first protective-side fire-resistant layer is directly ignited by the high-temperature fire-resistant layer and resulting in the phenomenon of interlayer smoldering, thereby reducing the risk of fireproof failure. In addition, it is possible to prevent 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 protective-side fire-resistant layer.

[0189] In a specific embodiment, the total thickness of the multiple fire-resistant layers 2 is T, and the porosity of the fire-resistant layer 2 is δ, satisfying: T ≥ 3.14e 4.58δ .

[0190] In a specific embodiment, to reduce the flow resistance, it is necessary to satisfy: T < 6.28e 4.58δ .

[0191] In a specific embodiment, the thickness of the protective-side fire-resistant layer 21b is T2, satisfying: T2 ≤ 1.57e 4.58δ .

[0192] In a specific embodiment, to obtain a better effect of extending the fireproof time and a smaller flow resistance, it is necessary to satisfy: 0.4 ≤ δ ≤ 0.6.

[0193] In a specific embodiment, the thickness of the fire-resistant layer 21a on the combustion side is T1, satisfying: T1 ≥ T2.

[0194] In a specific embodiment, when the long-time fireproof structure is actually applied, to obtain a better effect of extending the fireproof time and a smaller flow resistance, it is necessary to satisfy: T ≥ 30 mm.

[0195] In a specific embodiment, the gap value of the fire-resistant layer 21a on the combustion side is h1, and the gap value of the protective-side fire-resistant layer 21b is h2, satisfying: h1 ≤ h2.

[0196] In a specific embodiment, h1 ≤ MESG, preferably, h1 ≤ 0.5MESG.

[0197] In a specific embodiment, h2 ≤ MESG, preferably, h2 ≤ 0.8MESG.

[0198] In a specific embodiment, the gap of the burn-resistant layer 21a on the combustion side is axially deflected relative to the burn-resistant layer 21a on the combustion side, and the deflection angle is α, satisfying: T1 * tanα ≥ h1.

[0199] In a specific embodiment, the flow area of each burn-resistant layer 2 is not less than the flow area of the pressure relief air inlet end 11.

[0200] Axial heat insulation of fire-resistant structure (heat insulation support structure)

[0201] Referring to Figure 1 and Figure 2 , the long-term fire-resistant structure may include a heat-insulating support structure 3 provided between two adjacent burn-resistant layers 2, and the heat-insulating support structure 3 is in contact with the two adjacent burn-resistant layers 2.

[0202] The heat-insulating support structure 3 has a heat-insulating function and can effectively weaken the thermal radiation and heat conduction between its two adjacent burn-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-insulating support structure 3 also has a supporting function. When the downstream burn-resistant layer 2 is deformed by heat, it can support the deformed burn-resistant layer 2 to prevent it from coming into direct contact with the upstream burn-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 burn-resistant structure.

[0203] To improve the support strength, the heat-insulating support structure 3 can be arranged to form a support within the entire radial range of the burn-resistant layer 2, thereby effectively preventing the downstream burn-resistant layer 2 from deforming and collapsing after a long-term combustion. For example, referring to Figure 18 , a triangular heat-insulating support structure 3 can be adopted, and the diameter of the circumscribed circle of the triangle can be set to be equal to the diameter of the burn-resistant layer 2; or, referring to Figure 17 , a cross-shaped heat-insulating 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 burn-resistant layer 2.

[0204] To enhance the heat-insulating effect, the total contact area of the heat-insulating support structure 3 with the two adjacent burn-resistant layers 2 should be as small as possible. If the ratio of the total contact area of the heat-insulating support structure 3 with the two adjacent burn-resistant layers 2 to the cross-sectional area of the burn-resistant layer 2 is defined as Define the thermal conductivity of the heat-insulating support structure 3 as λ, then it satisfies: In other words, is related to λ.

[0205] In a specific embodiment, is not greater than 3%, preferably, is not greater than 1%.

[0206] In a specific embodiment, the heat-insulating support structure 3 forms a point contact with the fire-resistant layer 2. For example, the heat-insulating support structure 3 can contact the fire-resistant layer 2 by being provided with bump structures.

[0207] In a specific embodiment, the heat-insulating support structure 3 forms a line contact with the fire-resistant layer 2. For example, a slender cylindrical heat-insulating support structure 3 can be adopted.

[0208] In a specific embodiment, the heat-insulating support structure 3 forms a surface contact with the fire-resistant layer 2. For example, a slender rectangular heat-insulating support structure 3 can be adopted.

[0209] To improve the heat-insulating effect, it can also be achieved by increasing the thickness of the heat-insulating support structure 3.

[0210] In a specific embodiment, the heat-insulating support structure 3 is a multi-layer heat-insulating support structure. For example, referring to Figure 19 and Figure 20 , the multi-layer heat-insulating support structure can include a plurality of heat-insulating support units 31 stacked in sequence along the axial direction, that is, the total thickness of the heat-insulating support structure 3 is increased by stacking a plurality of independent heat-insulating support units 31; or, referring to Figure 21 , the multi-layer heat-insulating support structure can also include a heat-insulating support body portion 32a and a heat-insulating support protruding portion 32b protruding from the heat-insulating support body portion 32a along the axial direction, that is, the total thickness of the heat-insulating support structure 3 is increased by providing a heightening structure (heat-insulating support protruding portion 32b) in the integrated heat-insulating support structure 3.

[0211] In addition, the heat-insulating support structure 3 should be made of high-temperature-resistant materials to ensure that when the fire-resistant structure burns for a long time and continuously transfers heat to the heat-insulating support structure 3, the heat-insulating support structure 3 will not deform or deform excessively and lose its good support strength.

[0212] In a specific embodiment, the heat-resistant temperature of the heat-insulating support structure 3 is not less than 1000 °C.

[0213] In a specific embodiment, the linear change rate of the heat-insulating support structure 3 is not greater than 10%, preferably, the linear change rate of the heat-insulating support structure 3 is not greater than 5%, so that the heat-insulating support structure 3 can have no obvious deformation when heated for a long time.

[0214] Furthermore, the present invention does not limit the internal structure of the heat-insulating support structure 3. For example, the heat-insulating support structure 3 can be a solid-type heat-insulating support structure, a porous-type heat-insulating support structure with a porous structure, and a hollow-type heat-insulating support structure with a hollow cavity, etc.

[0215] Radial heat insulation of fire-resistant structure

[0216] Based on the content in the embodiment of the aforementioned air flow control method 3, obviously, when the fire-resistant structure is provided with one or more fire-resistant layers 2, a single fire-resistant layer 2 can refer to Figure 22 , divide the outer ring area 22a of the fire-resistant layer and the inner area of the fire-resistant layer located inside the outer ring area 22a of the fire-resistant layer; or, a single fire-resistant layer 2 can refer to Figure 24 , divide the outer ring area 22a of the fire-resistant layer, the inner ring area 22b of the fire-resistant layer, and the middle area 22c of the fire-resistant layer arranged in sequence from outside to inside.

[0217] 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, so that the inner area of the fire-resistant layer can be set as a closed heat insulation area, and the outer ring area 22a of the fire-resistant layer can allow the pressure relief air flow to pass through.

[0218] 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 extending the fire resistance duration.

[0219] In a specific embodiment, referring to Figure 23 , the fire-resistant layer 2 may include a first closed heat insulation disc 23a and a plurality of first fire-resistant discs 23b. Among them, both the outer ring area 22a of the fire-resistant layer and the inner area of the fire-resistant layer are arranged on the first closed heat insulation disc 23a. A plurality of first mounting openings are formed at intervals in the circumferential direction in the outer ring area 22a of the first closed heat insulation disc 23a, and the plurality of first fire-resistant discs 23b are respectively mounted in the plurality of first mounting openings.

[0220] With such a setting, the plurality of first fire-resistant discs 23b can all allow the pressure relief air flow to pass through, thereby ensuring the flowability of the outer ring area 22a of the fire-resistant layer. Except for the area where the plurality of first fire-resistant discs 23b are mounted in the first closed heat insulation disc 23a, the remaining areas cannot allow the pressure relief air flow to pass through, and at the same time have a heat insulation function, which can not only effectively slow down the transfer of the combustion heat of 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-resistant discs 23b, so that more combustion heat is dissipated to the outside atmosphere.

[0221] Referring to Figure 24 , when the fire-resistant layer 2 is provided with 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, the porosity of the inner ring area 22b of the fire-resistant layer can be zero, so that the inner ring area 22b of the fire-resistant layer can be set as a closed heat insulation area, and both the outer ring area 22a of the fire-resistant layer and the middle area 22c of the fire-resistant layer can allow the pressure relief air flow to pass through.

[0222] The above settings take into account the flow efficiency of the pressure relief air flow and retain 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 insulation 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 to the outside through the outer ring area 22a of the fire-resistant layer, thereby effectively extending the fire resistance duration.

[0223] In a specific embodiment, referring to Figure 26 , the fire-resistant layer 2 may include a second closed heat-insulating disc 24a, a plurality of second fire-blocking discs 24b, and a single third fire-blocking disc 24c. Among them, the outer ring area 22a, the inner ring area 22b, and the intermediate area 22c of the fire-resistant layer are all arranged on the second closed heat-insulating disc 24a. A plurality of second fitting openings are formed at intervals in the circumferential direction in the outer ring area 22a of the second closed heat-insulating disc 24a. The plurality of second fire-blocking discs 24b are respectively fitted into the plurality of second fitting openings one by one. A third fitting opening is provided in the intermediate area 22c of the second closed heat-insulating disc 24a, and the third fire-blocking disc 24c is fitted into the third fitting opening.

[0224] With such a setting, both the third fire-blocking disc 24c and the plurality of second fire-blocking discs 24b allow the pressure relief air flow to pass through, thereby ensuring the flowability of the intermediate area 22c and the outer ring area 22a of the fire-resistant layer. In addition, in the second closed heat-insulating disc 24a, except for the areas where the third fire-blocking disc 24c and the plurality of second fire-blocking discs 24b are fitted, the remaining areas do not allow the pressure relief air flow to pass through, and at the same time have a heat insulation 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 intermediate area 22c of the fire-resistant layer, but also slow down the heat transfer between the plurality of second fire-blocking discs 24b, so that more combustion heat is dissipated to the outside atmosphere.

[0225] In a specific embodiment, referring to Figure 25 , the fire-resistant layer 2 may include a fire-blocking ring 25a, a closed heat-insulating ring 25b, and a fourth fire-blocking disc 25c that are nested in sequence from the outside to the inside. Among them, the outer ring area 22a of the fire-resistant layer is arranged on the fire-blocking ring 25a, the inner ring area 22b of the fire-resistant layer is arranged on the closed heat-insulating ring 25b, and the intermediate area 22c of the fire-resistant layer is arranged on the fourth fire-blocking disc 25c.

[0226] With such a setting, both the fire-blocking ring 25a and the fourth fire-blocking disc 25c allow the pressure relief air flow to pass through, thereby ensuring the flowability of the outer ring area 22a and the intermediate area 22c of the fire-resistant layer. The closed heat-insulating ring 25b does not allow the pressure relief air flow to pass through, and at the same time has a heat insulation 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 that more combustion heat is dissipated to the outside atmosphere.

[0227] It should be noted that the above-mentioned first closed heat-insulating disc 23a, second closed heat-insulating disc 24a, closed heat-insulating ring 25b or other forms of closed heat-insulating structures should be made of materials with low thermal conductivity. The interior of these closed heat-insulating structures can be set as a hollow structure, for example. In the hollow state, it can be evacuated or filled with materials with low thermal conductivity to achieve good heat-insulating performance.

[0228] Stacked porous fire-resistant layer

[0229] The fire-resistant layer 2 can adopt structures such as a corrugated plate fire-resistant disc 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-resistant duration are provided.

[0230] 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.

[0231] Both the first layer shell 26a and the stacked particles 26b have high temperature resistance. There are multiple particle gaps formed between the plurality of stacked particles 26b, thus forming a porous structure and 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 interior of the fire-resistant 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 fire-resistant 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.

[0232] It should be noted that there is a risk that the plurality of stacked particles 26b 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, easily triggering flashback and resulting in fire resistance failure. Therefore, the thermal deformation of the stacked particles 26b should be minimized as much as possible.

[0233] 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 plurality of stacked particles 26b along the axial direction of the stacked porous fire-resistant layer to compact the plurality of stacked particles 26b, which can effectively reduce the thermal expansion amplitude of the plurality of stacked particles 26b, avoid excessive expansion of the particle gaps, and thus effectively reduce the probability of fire resistance failure.

[0234] In addition, the diameter d1 of the stacked particles 26b, the total stacked thickness T3 of the multiple stacked particles 26b along the axial direction of the stacked porous fire-resistant layer are related to the gas explosion grade. To achieve a better effect of extending the fire-blocking duration, d1 and T3 can be set according to the following relational expressions, which are as follows:

[0235] When the pressure-relief airflow is Class IIA gas, 1 ≤ [0.068ln(d1) + 0.31] * d1 / [(0.69 - 0.068ln(d1)] ≤ 1.5;

[0236] When the pressure-relief airflow is Class IIB3 gas, 0.6 ≤ [0.068ln(d1) + 0.31] * d1 / [(0.69 - 0.068ln(d1)] ≤ 1.2;

[0237] 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, 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.

[0238] If the combustible gas is a mixed gas, its MESG value can be calculated according to its different gas components, or it can be simplified to refer to the MESG value of the typical gas of the corresponding explosion grade. For example, propane is selected as the representative gas for Class IIA gas, and its MESG value is 0.93 mm; ethylene is selected as the representative gas for Class IIB3 gas, and its MESG value is 0.67 mm; hydrogen is selected as the representative gas for Class IIC gas, and its MESG value is 0.31 mm.

[0239] For the stacked porous fire-resistant layer, the pressure-relief airflow needs to pass through the particle stacking gaps. When the particle size of the stacked particles 26b is larger, the particle stacking gaps are also larger, and too large particle stacking gaps will cause the flame to burn in the gaps, thereby causing flashback and resulting in the failure of fire blocking.

[0240] And the above relational expressions limit the equivalent pore size represented by the gap value formed between the stacked particles 26b, which can achieve the quenching of the flame between the pores, and thus achieve fire blocking. At the same time, in order to ensure the flow performance, the total stacked thickness T3 is limited.

[0241] 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.

[0242] Both the second layer shell and the lightweight spheres have high temperature resistance. There are multiple sphere gaps formed between the multiple lightweight spheres, thus forming a porous structure, and therefore having a certain fluidity. In addition, a plurality of second layer shell through holes are provided on both the upstream side wall and the downstream side wall of the second layer shell. The pressure relief air flow can flow into the fire-resistant layer through the plurality of second layer 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 layer shell through holes on the downstream side wall. To ensure that the lightweight spheres do not fall out of the second layer shell through holes, the diameter of the second layer shell through holes should be smaller than the diameter of the lightweight spheres.

[0243] 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 multiple lightweight spheres to rotate, realizing the heat and cold cycle of the lightweight spheres, prolonging the heat transfer time, and being beneficial to improving the fire resistance performance.

[0244] Convex design of the combustion side fire-resistant layer

[0245] By setting at least a part of the downstream side surface of the combustion-side fire-resistant layer 21a to protrude downward, the area of the downstream side surface of the combustion-side fire-resistant layer 21a is enlarged, which can strengthen the heat dissipation effect of the downstream side surface, effectively improve the problem of combustion heat accumulation, and thus prolong the fire resistance duration of the combustion-side fire-resistant layer 21a.

[0246] For example, the downstream side surface of the combustion-side fire-resistant layer 21a can be set as a fire-resistant layer curved surface. The fire-resistant layer curved surface has at least one protruding position, and can be in different specific forms such as a variable curvature curved surface and a fixed curvature curved surface; when adopting a fixed curvature curved surface with a single protruding position, the fire-resistant layer curved surface is a partial spherical surface (i.e., a part of a complete spherical surface). In this way, it is possible to balance improving the heat dissipation effect and simplifying the processing, which is beneficial to reducing the production cost.

[0247] In other words, the specific form of the protruding area of the downstream side surface of the combustion-side fire-resistant layer 21a in this embodiment is not limited, as long as it is beneficial to improving the heat dissipation effect.

[0248] In a specific embodiment, refer to Figure 28, the burn-resistant layer 21a on the combustion side includes a burn-resistant layer disc portion 27a and a burn-resistant layer convex portion 27b connected to the downstream side of the burn-resistant layer disc portion 27a. At this time, the downstream side surface of the burn-resistant layer convex portion 27b is set as a partial spherical surface protruding downstream. In this way, in the downstream side portion of the burn-resistant layer 21a on the combustion side, the burn-resistant layer convex portion 27b can improve the heat dissipation effect. In the upstream side portion of the burn-resistant layer 21a on the combustion side, the shape of the burn-resistant layer disc portion 27a is the same as that of the burn-resistant layer 21b on the protection side. The upstream side surface of the burn-resistant layer disc portion 27a and the downstream side surface of the burn-resistant layer 21b on the protection side are both flat surfaces, which can ensure that the distance between the upstream side surface of the burn-resistant layer disc portion 27a and the downstream side surface of the burn-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.

[0249] In addition, the radian corresponding to the partial spherical surface is β, which is related to the structural dimensions of the burn-resistant layer 21a on the combustion side and the fire resistance and burn resistance level.

[0250] The fire resistance and burn resistance level is classified according to ISO16852. Generally, the commonly used fire resistance and burn resistance levels are IIA, IIB3, and IIC, and their typical representative combustible gases are n-hexane, ethylene, and hydrogen respectively.

[0251] To better represent the relationship between β and the structural dimensions of the burn-resistant layer 21a on the combustion side and the fire resistance and burn 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 burn resistance level. At this time, it satisfies:

[0252] β = 3.78ε -0.8 arctan(T4 / R1);

[0253] Among them, ε is the MESG value of the typical representative combustible gases n-hexane, ethylene, and hydrogen, R1 is the radius of the burn-resistant layer disc portion 27a, and T4 is the thickness of the burn-resistant layer disc portion 27a.

[0254] By designing the burn-resistant layer 21a on the combustion side through the above relational formula, a better effect of extending the fire resistance duration can be obtained.

[0255] High-temperature resistant coating

[0256] To improve the fire resistance and burn resistance performance, at least a high-temperature resistant coating can be applied to the downstream side surface of the burn-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 applied.

[0257] In a specific embodiment, a high-temperature resistant coating is provided to cover the outer surface of the fire-resistant layer 2, including the entire surface composed of the downstream side, upstream side, peripheral wall surface, surface of holes or gaps of the fire-resistant layer 2 itself, etc., so as to improve the fire-blocking and fire-resistant performance of the fire-resistant layer 2 over a larger area.

[0258] In a specific embodiment, for the combustion-side fire-resistant layer 21a, it is preferable to coat a high-temperature resistant coating with a high heat radiation rate or a high reflectivity. For example, the reflectivity of the high-temperature resistant coating is not less than 70%, and preferably, the reflectivity is not less than 90%.

[0259] 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.

[0260] In a specific embodiment, for the protection-side fire-resistant layer 21b, it is preferable to coat a high-temperature resistant coating with a low thermal conductivity. For example, the thermal conductivity of the high-temperature resistant coating is not greater than 0.2 W / (m·K).

[0261] 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.

[0262] 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:

[0263]

[0264] T0 ≥ 3.14e 1.31MESG+1.88 ;

[0265] Among them, 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.

[0266] It should be noted that the fire-blocking gap characteristic value h g of the fire-resistant layer 2 is closely related to the fire-blocking and fire-resistant performance. When the fire-blocking gap characteristic value h g is relatively large, the flow rate of the relieved pressure 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 fire-resistant layer 2, thereby affecting the fire-blocking and fire-resistant effect; and when the fire-blocking gap characteristic value h gWhen it is relatively small, although the flow rate of the venting pressure-relief air flow is small and its combustion heat is low, its flow performance is poor. Therefore, in practical applications, in order to obtain better flow performance, a larger fire-resistant layer area is required. As the area of the fire-resistant layer increases, the total combustion heat does not decrease, and the heat in the middle region of the fire-resistant layer becomes more difficult to dissipate due to the increase in the area of the fire-resistant layer, thus affecting the fire-blocking and fire-resistant performance.

[0267] In the case of coating with a high-temperature resistant coating, the fire-blocking gap characteristic value of the fire-resistant layer 2 is h g changes. Therefore, preferably, the fire-blocking gap characteristic value is h through the above relationship g and the thickness T of the high-temperature resistant coating that affects the fire-blocking gap characteristic value h g etc. are limited. t etc. are limited.

[0268] Long-term fire blocking condition not less than 2 hours

[0269] Currently, in some domestic storage tanks or tank farms, since the nitrogen sealing amount is difficult to meet, 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 fire-blocking and fire-resistant atmospheric deflagration type flame arrester, and the fire-blocking and fire-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 fire-blocking and fire-resistant duration of not less than 2 hours.

[0270] Based on the foregoing concept, the present invention further provides embodiments of a long-time fire-blocking structure with a fire-blocking 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 fire-blocking duration.

[0271] In the experimental tests of multiple embodiments and comparative examples, the pipe diameter specification of the pressure-relief air inlet end 11 is DN100, and the experimental test medium uses a mixture of n-hexane and air recommended by ISO16852, where the volume fraction of n-hexane in the mixture is 2.1%. In addition, during the experimental test process, the temperature changes on the upstream side and downstream side of the fire-resistant structure, the duration required for the upstream side temperature to rise by 20 °C, and whether the fire can be blocked after burning for 2 hours are concerned.

[0272] Example 1:

[0273] Referring to Figure 8 and Figure 18 , the specific structural parameters in the long-time fire-blocking structure are as follows:

[0274] The cavity 13 adopts a coaxial equal-diameter cavity, the diameter of the cavity 13 is D, the diameter of the pressure-relief air inlet end 11 is d, and D = 2d;

[0275] 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;

[0276] 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;

[0277] The protection side fire-resistant layer 21b uses a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0278] The combustion side fire-resistant layer 21a uses a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0279] 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.

[0280] Example 2:

[0281] Refer to Figure 4 、 Figure 5 and Figure 18 The specific structural parameters in the long-term fireproof structure are as follows:

[0282] The cavity 13 uses 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;

[0283] The middle flow guide member 4 uses 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;

[0284] The protection side fire-resistant layer 21b uses a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0285] The combustion side fire-resistant layer 21a uses a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0286] 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.

[0287] Example 3:

[0288] Reference Figure 10 and Figure 18 , the specific structural parameters in the long-time fire-resistant structure are as follows:

[0289] 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;

[0290] 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;

[0291] The first annular flow guide member 5 adopts a metal annular plate with inner and outer diameters of d and 1.4d respectively, and is axially spaced 0.15d from the middle flow guide member 4;

[0292] The second annular flow guide member 6 adopts a metal annular plate with inner and outer diameters of 1.3d and 1.6d respectively, and is axially spaced 0.15d from the first annular flow guide member 5;

[0293] 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;

[0294] 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;

[0295] 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 combustion side fire-resistant layer 21a.

[0296] Example 4:

[0297] Reference Figure 24 and Figure 18 , the specific structural parameters in the long-time fire-resistant structure are as follows:

[0298] 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;

[0299] 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;

[0300] 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;

[0301] The fire-resistant layer 21b on the protection side includes a corrugated plate fireproof disc, a closed heat-insulating metal ring, and a corrugated plate fireproof ring that are 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 its hollow cavity. For the corrugated plate fireproof disc, its diameter is 0.8d, its thickness is 15 mm, and the fireproof gap value is 0.45 mm. For the corrugated plate fireproof ring, its inner and outer diameters are 1.3d and 1.6d respectively, its thickness is 15 mm, and the fireproof gap value is 0.45 mm.

[0302] The fire-resistant layer 21a on the combustion side includes a corrugated plate fireproof disc, a closed heat-insulating metal ring, and a corrugated plate fireproof ring that are 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 its hollow cavity. For the corrugated plate fireproof disc, its diameter is 0.8d, its thickness is 15 mm, and the fireproof gap value is 0.45 mm. For the corrugated plate fireproof ring, its inner and outer diameters are 1.3d and 1.6d respectively, its thickness is 15 mm, and the fireproof gap value is 0.45 mm.

[0303] 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 circumscribed circle of the triangle is equal to the diameter of the fire-resistant layer 21a on the combustion side.

[0304] Example 5:

[0305] Referring to Figure 9 and Figure 18 , the specific structural parameters in the long-time fireproof structure are as follows:

[0306] 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;

[0307] 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;

[0308] 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;

[0309] Both of the fire-resistant layers 21b on the protection side adopt corrugated plate fireproof discs, both with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0310] The fire-resistant layer 21a on the combustion side adopts a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0311] Both of the heat-insulating support structures 3 adopt high-temperature resistant metal wire with a cross-sectional diameter of 2 mm. Both of the heat-insulating support structures 3 are arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the fire-resistant layer 21a on the combustion side.

[0312] Example 6:

[0313] Referring to Figure 8 and Figure 19 , the specific structural parameters in the long-time fireproof structure are as follows:

[0314] 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;

[0315] 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;

[0316] 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;

[0317] The protection side fire-resistant layer 21b adopts a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0318] The combustion side fire-resistant layer 21a adopts a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0319] 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 it is set into a triangle. The diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion side fire-resistant layer 21a.

[0320] Example 7:

[0321] Referring to Figure 8 and Figure 21 , the specific structural parameters in the long-time fireproof structure are as follows:

[0322] 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;

[0323] 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;

[0324] 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;

[0325] The protection side fire-resistant layer 21b adopts a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0326] The combustion side fire-resistant layer 21a adopts a corrugated plate fireproof disc with a diameter of 2d, a thickness of 15 mm, and a fireproof gap value of 0.45 mm;

[0327] The heat-insulating support structure 3 uses a high-temperature resistant metal wire with a heat-insulating support body part 32a and a heat-insulating support protruding part 32b. The cross-sectional diameter of the heat-insulating support body part 32a is 2 mm, the thickness of the heat-insulating support protruding part 32b protruding from the heat-insulating support body part 32a is 1 mm, and the heat-insulating support protruding part 32b is a hemispherical structure.

[0328] Example 8:

[0329] Refer to Figure 6 and Figure 18 , the long-time fire-resistant structure can be applied as a breather valve, and its specific structural parameters are as follows:

[0330] The cavity 13 adopts a coaxial and equal-diameter cavity. The diameter of the cavity 13 is D, the diameter of the pressure relief air inlet end 11 is d, and D = 2d;

[0331] A first flange is provided at the upstream end of the pressure relief air inlet end 11;

[0332] The middle flow guiding member 4 serves as the pressure relief valve disc 43 of the breather valve. The pressure relief valve disc 43 is connected to a first guide rod. 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 splitting the flow; among them, the diameter of the pressure relief valve disc 43 is d, and it is spaced 0.25d from the upstream side wall of the cavity 13;

[0333] The first annular flow guiding member 5 adopts a metal annular plate, and its inner and outer diameters are 1.3d and 1.6d respectively, and it is axially spaced 0.25d from the middle flow guiding member 4;

[0334] The protective side fire-resistant layer 21b adopts a corrugated plate fire-resistant disc, its diameter is 2d, its thickness is 15 mm, and the fire-resistant gap value is 0.45 mm;

[0335] The combustion side fire-resistant layer 21a adopts a corrugated plate fire-resistant disc, its diameter is 2d, its thickness is 15 mm, and the fire-resistant gap value is 0.45 mm;

[0336] The heat-insulating support structure 3 uses a high-temperature resistant metal wire, its cross-sectional diameter is 2 mm, and 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 combustion side fire-resistant layer 21a.

[0337] Example 9:

[0338] Refer to Figure 7 and Figure 18 , the long-time fire-resistant structure can be applied in a breathing valve, and its specific structural parameters are as follows:

[0339] 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;

[0340] A second flange is provided at the upstream end of the pressure relief and air inlet end 11;

[0341] The middle flow guide member 4 serves as the pressure relief valve disc 43 of the breather valve. The pressure relief valve disc 43 is connected to the second guide rod, and the second guide rod can slide in the second guide groove in the upstream and downstream directions. The pressure relief valve disc 43 can switch the on-off state between the cavity 13 and the pressure relief and 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 and air inlet end 11, the pressure relief valve disc 43 plays a role in guiding and splitting the flow; among them, the diameter of the pressure relief valve disc 43 is d, and it is spaced 0.25d from the upstream side wall of the cavity 13;

[0342] The first annular flow guide member 5 adopts a metal annular plate, and its inner and outer diameters are 1.3d and 1.6d respectively, and it is axially spaced 0.25d from the middle flow guide member 4;

[0343] The protective side fire-resistant layer 21b adopts a corrugated plate firestop disc, its diameter is 2d, its thickness is 15 mm, and the firestop gap value is 0.45 mm;

[0344] The combustion side fire-resistant layer 21a adopts a corrugated plate firestop disc, its diameter is 2d, its thickness is 15 mm, and the firestop gap value is 0.45 mm;

[0345] The heat insulation support structure 3 adopts high-temperature resistant metal wires, its cross-sectional diameter is 2 mm, and the heat insulation support structure 3 is arranged in a triangle, and the diameter of the circumscribed circle of the triangle is equal to the diameter of the combustion side fire-resistant layer 21a.

[0346] Comparative Example 1:

[0347] Refer to Figure 29 , the firestop structure in the figure can be regarded as a structural simplification and adjustment based on the long-term firestop 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.

[0348] The difference between Comparative Example 1 and Embodiment 1 is that: the firestop structure in Comparative Example 1 does not have the heat insulation support structure 3, the middle flow guide member 4 and the first annular flow guide member 5, and there is no gap left between the combustion side fire-resistant layer 21a and the protective side fire-resistant layer 21b.

[0349] Comparative Example 2:

[0350] Continue with Figure 29As 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.

[0351] The following table shows the comparison of experimental data between Examples 1-9 and Comparative Examples 1-2:

[0352]

[0353] As can be seen from the above table, the long-term fire-blocking structure of the present invention, when provided with a multi-layer fire-resistant structure in different forms, a heat-insulating support structure 3 and adopting an 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.

[0354] 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.

[0355] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0356] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0357] 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 fireproof structure with axial heat insulation function, Characterized in that, The long-time fireproof 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) communicating 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 in sequence along the axis of the pressure relief air outlet end (12), 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); An insulation support structure (3), arranged between two adjacent fire-resistant layers (2) and in contact with the two adjacent fire-resistant layers (2); 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 fireproof structure with axial heat insulation function according to claim 1, Characterized in that, The proportion of the total contact area of the heat insulation support structure (3) with two adjacent refractory layers (2) to the cross-sectional area of the refractory layer (2) is The heat conductivity of the heat insulation support structure 3 is λ, satisfying:

3. The long-time fireproof structure with axial heat insulation function according to claim 2, Characterized in that, Not more than 3%, preferably, Not more than 1%.

4. The long-time fireproof structure with axial heat insulation function according to claim 1, Characterized in that, The protection-side refractory layer (21b) closest to the combustion-side refractory layer (21a) is the first protection-side refractory layer. The distance between the combustion-side refractory layer (21a) and the first protection-side refractory layer is L, and the diameter of the first protection-side refractory layer is D2, satisfying: L = 3.31 + 2.615MESG - 0.012D 2 , where MESG is the maximum experimental safe gap.

5. The long-time fireproof structure with axial heat insulation function according to claim 1, Characterized in that, The heat-resistant temperature of the insulation support structure (3) is not less than 1000 °C; and / or, the linear change rate of the insulation support structure (3) is not more than 10%, preferably, the linear change rate of the insulation support structure (3) is not more than 5%.

6. The long-time fireproof structure with axial heat insulation function according to claim 1, Characterized in that, The insulation support structure (3) is a multi-layer insulation support structure, the multi-layer insulation support structure includes a plurality of insulation support units (31) arranged in layers in sequence along the axis; or, the multi-layer insulation support structure includes an insulation support body part (32a) and an insulation support protruding part (32b) protruding from the insulation support body part (32a) along the axis.

7. The long-time fireproof structure with axial heat insulation function according to claim 1, Characterized in that, The insulation support structure (3) includes a solid insulation support structure, a porous insulation support structure with a porous structure, and a hollow insulation support structure with a hollow cavity.

8. The long-time fireproof structure with axial heat insulation function according to claim 1, Characterized in that, The insulation support structure (3) forms a point contact, a line contact or a surface contact with the fire-resistant layer (2).

9. The long-time fireproof structure with axial heat insulation function according to any one of claims 1 to 8, Characterized in that, The flow guiding structure includes: A cavity flow guiding structure is arranged inside the cavity (13) and is 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) that flow 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 that of the inner region air flow (G12), and / or making the flow rate of the outer region air flow (G11) greater than that of the inner region air flow (G12).

10. The long-time fire resistance structure with axial heat insulation function according to any one of claims 1 to 8, characterized in that, the flow guiding structure includes: A cavity flow guiding structure is arranged inside the cavity (13) and is used for dividing the pressure relief air flow flowing into the cavity (13) into an outer ring region air flow (G21), an inner ring region air flow (G22) and a middle region air flow (G23) that are sequentially distributed from outside to inside in the cavity (13), and making the flow rates of the outer ring region air flow (G21), the middle region air flow (G23) and the inner ring region air flow (G22) decrease in sequence, and / or making the flow rates of the outer ring region air flow (G21), the middle region air flow (G23) and the inner ring region air flow (G22) decrease in sequence.

11. The long-time fire resistance structure with axial heat insulation function according to any one of claims 1 to 8, 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 for dividing the pressure relief air flow flowing into the pressure relief air inlet end (11) into an outer layer region air flow (G31) and an inner region air flow (G32) that flow in the outer layer region and the inner region of the pressure relief air inlet end (11) respectively, and making the flow rate of the outer layer region air flow (G31) greater than that of the inner region air flow (G32), and / or making the flow rate of the outer layer region air flow (G31) greater than that of the inner region air flow (G32).

12. The long-time fire resistance structure with axial heat insulation function according to any one of claims 1 to 8, 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 for dividing the pressure relief air flow flowing into the pressure relief air inlet end (11) into an outer layer region air flow (G31), an inner layer region air flow (G321) and a middle region air flow (G322) that flow in the outer layer region, the inner layer region and the middle region of the pressure relief air inlet end (11) respectively, and making the flow rates of the outer layer region air flow (G31), the middle region air flow (G322) and the inner layer region air flow (G321) decrease in sequence, and / or making the flow rates of the outer layer region air flow (G31), the middle region air flow (G322) and the inner layer region air flow (G321) decrease in sequence.

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