Boiler explosion door
The boiler explosion-proof door structure, which combines guide columns and sealing grooves, solves the problems of gaps in the sealing surface and slow response speed of existing explosion-proof doors, achieving efficient sealing and rapid pressure relief, and improving the safety and economy of boiler operation.
Patent Information
- Application Number
- CN202520623701.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-04-03
AI Technical Summary
Existing gravity-type explosion-proof doors have gaps in the sealing surface due to vibration and temperature changes during long-term operation, posing a safety hazard of outside air and impurities entering the equipment, and their response speed is slow; hinged explosion-proof doors have a large door body weight, and their response speed is not compatible with the propagation of boiler pressure waves; rupture disc explosion-proof doors are expensive and have a long time to resume production.
Design a boiler explosion-proof door, which adopts a fixed seat and cover plate structure, guide columns and sealing grooves cooperate, the cover plate is positioned by guide holes, the sealing flange cooperates with the sealing groove, guide sleeve and spring enhance stability, heat-resistant layer improves heat resistance, and multiple guide columns and kits improve movement stability and sealing effect.
It improves sealing performance and reliability, reduces leakage risk, enhances response speed and service life, reduces maintenance costs, and improves the safety and economy of boiler operation.
Smart Images
Figure CN223924877U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of explosion doors, particularly relates to a boiler explosion door. BACKGROUND
[0002] In the heat energy application equipment such as fuel oil, fuel gas boiler, to cope with the internal instantaneous explosion, explosion structural serious damage, usually install explosion door. The existing explosion door is mainly divided into gravity type, hinge type and bursting disc type, wherein gravity type explosion door relies on self-weight sealing, but in the long-term operation of equipment, affected by vibration, temperature change etc., the sealing surface is easy to appear gap, and the outside air and impurities are easy to enter the equipment, affect normal operation and exist security hidden danger, can not satisfy the production demand. SUMMARY
[0003] The utility model discloses at least one of the technical problems in the prior art. To this end, the utility model provides a boiler explosion door, which can improve the sealing effect and enhance the reliability.
[0004] The boiler explosion door according to the first aspect of the utility model, including fixed seat and cover plate, the fixed seat is fixedly connected to the explosion opening of the boiler, the upper end of the fixed seat is provided with sealing groove, the sealing groove is arranged around the explosion opening, the fixed seat is fixedly connected with the guide column;The cover plate is arranged at the upper end of the fixed seat, the cover plate is provided with a guide hole, the guide column is arranged in the guide hole, the lower end of the cover plate is provided with a sealing convex edge, the sealing convex edge is arranged along the circumference of the cover plate, the sealing convex edge is arranged in the sealing groove, and the sealing convex edge abuts against the bottom wall of the sealing groove.
[0005] The boiler explosion door according to the utility model has at least the following beneficial effects: the boiler is provided with an explosion opening, the fixed seat is fixedly connected to the explosion opening, the sealing groove is arranged at the upper end of the fixed seat, and the sealing groove is arranged around the explosion opening. The guide column is fixed on the fixed seat, so that the cover plate can be positioned at the upper end of the fixed seat through the guide hole. The lower end of the cover plate is provided with a sealing convex edge, and the sealing convex edge is arranged along the circumference of the cover plate. The sealing convex edge can abut against the bottom wall of the sealing groove, so that the fixed seat and the cover plate can be connected tightly, and the sealing effect is improved. The cover plate can slide along the axial direction of the guide column. When the internal pressure of the boiler increases, the cover plate can be pushed to move away from the fixed seat, which facilitates the pressure release in the boiler and improves the reliability. When the cover plate is reset, the cover plate can be guided to move in the direction of the guide column, so that the sealing convex edge can abut against the bottom wall of the sealing groove accurately. The sealing effect of the fixed seat and the cover plate is improved, the leakage path of the flue gas in the boiler is prolonged, the risk of leakage is reduced, and the reliability is improved.
[0006] According to some embodiments of the utility model, the cover plate is connected with a guide sleeve, the guide sleeve is fixedly connected in the guide hole, and the guide column is arranged in the guide sleeve.
[0007] According to some embodiments of the utility model, a fillet is arranged between the inner side wall and the end face of the guide sleeve.
[0008] According to some embodiments of the utility model, the number of the guide column and the guide sleeve is multiple, the multiple guide columns are evenly arranged along the circumference of the fixed base, and the guide column and the guide sleeve are one-to-one corresponding.
[0009] According to some embodiments of the utility model, the multiple guide columns are arranged along the vertical direction.
[0010] According to some embodiments of the utility model, the upper end of the guide column is connected with a positioning plate, a plurality of positioning holes are formed in the positioning plate along the circumference, the guide column is arranged in the positioning hole, and the guide column and the positioning hole are one-to-one corresponding.
[0011] According to some embodiments of the utility model, two nuts are threadedly connected with the guide column, and the positioning plate is arranged between the two nuts.
[0012] According to some embodiments of the utility model, the guide column is sleeved with a spring, and the cover plate can abut against the spring.
[0013] According to some embodiments of the utility model, along the axial direction of the guide column, the length of the spring is less than the length of the guide column, and the spring is arranged at the end of the guide column away from the fixed base.
[0014] According to some embodiments of the utility model, the lower end of the cover plate is fixedly provided with a heat-resistant layer, and the heat-resistant layer is located in the explosion-proof opening.
[0015] The additional aspects and advantages of the utility model will be partially given in the following description, partially will become obvious from the following description, or will be understood through the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS
[0016] The utility model will be further explained in combination with the drawings and embodiments, wherein:
[0017] Figure 1 It is the schematic view of boiler explosion door of the utility model embodiment;
[0018] Figure 2 It is Figure 1 It is the A place partial close -up of of
[0019] Figure 3The utility model discloses a fixed seat of boiler explosion door's schematic diagram of embodiment of the utility model;
[0020] Figure 4 The utility model discloses a cover plate of boiler explosion door's schematic diagram of embodiment of the utility model;
[0021] Figure 5 The utility model discloses a guide sleeve of boiler explosion door's schematic diagram of embodiment of the utility model;
[0022] Figure 6 The utility model discloses a positioning plate of boiler explosion door's schematic diagram of embodiment of the utility model;
[0023] Figure 7 The utility model discloses a running schematic diagram of boiler explosion door's schematic diagram of embodiment of the utility model;
[0024] Figure 8 The schematic diagram of prior art boiler explosion door Figure 1 ;
[0025] Figure 9 The schematic diagram of prior art boiler explosion door Figure 2 .
[0026] Reference signs:
[0027] Fixed seat 100, sealing groove 110, guide column 120, positioning plate 130, positioning hole 131, nut 132, spring 140;
[0028] Cover plate 200, guide hole 210, sealing convex edge 220, guide sleeve 230, round angle 231, heat resistance layer 240;
[0029] Explosion-proof opening 310. Specific implementation
[0030] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as the limitation of the utility model.
[0031] In the description of the utility model, it is understood that the orientation description, such as the orientation or position relationship of up, down, front, back, left, right and the like, is based on the orientation or position relationship shown in the drawings, only for the convenience of describing the utility model and simplifying the description, and is not indicative or implied that the indicated device or element must have a particular orientation, a particular orientation and operation, therefore, it cannot be understood as the limitation of the utility model.
[0032] In the description of the utility model, if several mean one or more, multiple means more than two, greater than, less than, exceed and the like are understood as not including the number, above, below, within and the like are understood as including the number. If it is described to the first, the second is only used for distinguishing the purpose of technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.
[0033] In the description of the utility model, unless otherwise explicitly limited, the words such as setting, installation, connection should be understood in a broad sense, and the person skilled in the art can reasonably determine the specific meaning of the above words in the utility model according to the specific content of the technical scheme.
[0034] In related technologies, in order to deal with the structural damage caused by internal instantaneous deflagration and explosion of fuel, gas boiler and other heat energy application equipment, explosion doors are usually installed. The existing explosion doors are mainly divided into gravity type, hinge type and bursting disc type.
[0035] Referring to Figure 8 , the gravity type explosion door relies on self-weight sealing, and the door body is pressed in the explosion opening through the spring, but in the long-term operation of the equipment, affected by vibration, temperature change and the like, the sealing surface between the door body and the explosion opening is easy to appear gap, and the outside air and impurities are easy to enter the equipment, and the spring is easy to relax stress in long-term high temperature environment, which affects normal operation and exists safety hidden danger.
[0036] Referring to Figure 9 , the door body of the hinge type explosion door is connected in the explosion opening through the hinge, but the weight of the door body itself is large, which has the problem of large rotational inertia, resulting in slow response speed of the door body, unable to quickly relieve the pressure of the boiler, unable to match the pressure wave propagation speed of the boiler, and unable to meet the production demand.
[0037] Although the bursting disc type explosion door can realize accurate bursting pressure and good sealing property, it belongs to disposable consumables, and the replacement cost is high, the reproduction time is long, and the economy of use cannot be met.
[0038] Therefore, the utility model provides a boiler explosion door, which can improve the sealing effect and enhance the reliability.
[0039] It can be understood that referring to Figures 1 to 4 , and Figure 7The utility model discloses a boiler explosion door, including fixed seat 100 and apron 200, fixed seat 100 fixed connection is in the explosion -proof opening 310 of boiler, and the upper end of fixed seat 100 is provided with sealing groove 110, and sealing groove 110 is arranged around explosion -proof opening 310, and fixed seat 100 is fixedly connected with guide column 120, apron 200 is arranged in the upper end of fixed seat 100, and apron 200 is provided with guide hole 210, and guide column 120 is arranged in guide hole 210, and the lower end of apron 200 is provided with sealing convex edge 220, and sealing convex edge 220 is arranged along the circumference of apron 200, and sealing convex edge 220 is arranged in sealing groove 110, and sealing convex edge 220 abuts the bottom wall of sealing groove 110.
[0040] The boiler is provided with explosion -proof opening 310, and fixed seat 100 is fixedly connected in explosion -proof opening 310, and sealing groove 110 is arranged in the upper end of fixed seat 100, and sealing groove 110 is arranged around explosion -proof opening 310, and guide column 120 is fixed on fixed seat 100, so that apron 200 can be positioned in the upper end of fixed seat 100 through guide hole 210, and the lower end of apron 200 is provided with sealing convex edge 220, and sealing convex edge 220 is arranged along the circumference of apron 200, so that sealing convex edge 220 can abut the bottom wall of sealing groove 110, so that fixed seat 100 and apron 200 can be connected closely, and the sealing effect is improved. Apron 200 can slide along the axial direction of guide column 120, when the pressure inside the boiler increases, apron 200 can be pushed to move away from fixed seat 100, facilitating the pressure release in the boiler, and improving reliability, when apron 200 resets, apron 200 can guide the moving direction through guide column 120, so that sealing convex edge 220 can abut the bottom wall of sealing groove 110 accurately, improve the sealing effect of fixed seat 100 and apron 200, and can prolong the leakage path of flue gas in the boiler, reduce the risk of leakage, and improve reliability.
[0041] Wherein, the shape of sealing groove 110 and sealing convex edge 220 is annular, so that when apron 200 abuts the upper end of fixed seat 100 through gravity, sealing groove 110 and sealing convex edge 220 cooperate to tightly connect fixed seat 100 and apron 200 together, not only can prolong the leakage path of flue gas, but also can change the leakage direction of flue gas, so as to increase the leakage resistance of flue gas, and reduce the risk of leakage.
[0042] In addition, by setting sealing groove 110 and sealing convex edge 220 to seal fixed seat 100 and apron 200, the deformation gap of fixed seat 100 or apron 200 caused by temperature or pressure change can be avoided, and the sealing performance and reliability can be improved.
[0043] It should be noted that fixed seat 100 can be fixedly connected to the explosion -proof opening 310 of the boiler by welding.
[0044] It can be understood that, with reference to Figure 1 The cover plate 200 is connected with a guide sleeve 230, the guide sleeve 230 is fixedly connected in the guide hole 210, and the guide column 120 is arranged in the guide sleeve 230. By arranging the guide sleeve 230 to be fixed in the guide hole 210 and arranging the guide column 120 to pass through the guide sleeve 230, the stability of the cover plate 200 in axial sliding along the guide column 120 can be enhanced, the cover plate 200 can be prevented from shaking, deviating or being stuck during movement, the smoothness and reliability of the explosion venting can be improved, the sealing convex edge 220 can be more accurately abutted against the bottom wall of the sealing groove 110 when the cover plate 200 is reset, the sealing effect can be further improved, the opening and closing actions of the cover plate 200 can be accurate, the risk of flue gas leakage in the boiler can be reduced, and the operation safety and reliability of the boiler can be improved.
[0045] In addition, by arranging the guide sleeve 230, the cover plate 200 and the guide column 120 can be separated, direct friction between the cover plate 200 and the guide column 120 can be avoided, the wear rate can be slowed down, the service life can be prolonged, the maintenance cost can be reduced, and the use economy can be improved.
[0046] Specifically, with reference to Figure 1 and Figure 5 A fillet 231 is arranged between the inner side wall and the end face of the guide sleeve 230. By arranging the fillet 231 between the inner side wall and the end face of the guide sleeve 230, the frictional resistance between the guide column 120 and the edge of the end face of the guide sleeve 230 during sliding can be reduced, stress concentration and scraping wear caused by the sharp edge of the guide sleeve 230 can be avoided, and thus the wear of the guide column 120 and the guide sleeve 230 can be further slowed down, and the service life of the guide column 120 and the guide sleeve 230 can be prolonged.
[0047] Specifically, with reference to Figure 1 The number of the guide columns 120 and the guide sleeves 230 is each set to be multiple, the multiple guide columns 120 are arranged at equal intervals in the circumferential direction of the fixed seat 100, and the guide column 120 and the guide sleeve 230 are in one-to-one correspondence. The multiple guide columns 120 are arranged at equal intervals in the circumferential direction of the fixed seat 100, and the guide column 120 and the guide sleeve 230 are in one-to-one correspondence, the movement stability and balance of the cover plate 200 on the fixed seat 100 can be enhanced, the cooperation of the multiple guide columns 120 and the multiple guide sleeves 230 can improve the guidance and support of the cover plate 200 when the cover plate 200 slides axially along the guide column 120, the cover plate 200 can be prevented from tilting or deviating due to uneven force, and the cover plate 200 can be smoothly and accurately opened and closed.
[0048] In addition, the plurality of guide columns 120 and the plurality of guide sleeves 230 jointly bear the frictional force during the movement of the cover plate 200, thereby reducing the wear rate of the single guide column 120 and the guide sleeve 230, further prolonging the service life, and further improving the overall sealing performance of the boiler explosion door. The plurality of guide columns 120 and the plurality of guide sleeves 230 can guide the sealing convex edge 220 to abut against the bottom wall of the sealing groove 110 more accurately, thereby reducing the risk of leakage and improving the safety and reliability of the boiler operation.
[0049] Specifically, referring to Figure 1 , the plurality of guide columns 120 are arranged in the vertical direction. The plurality of guide columns 120 are arranged in the vertical direction, which can guide the sliding of the cover plate 200 on the guide column 120 by gravity. When the pressure inside the boiler increases and pushes the cover plate 200 to move upward, the vertically arranged guide column 120 can guide the cover plate 200 to quickly rise in the vertical direction, thereby improving the response speed of the boiler explosion door, shortening the opening time of the cover plate 200, avoiding the accumulation of pressure in the boiler, and helping to protect the structure of the boiler; when the pressure inside the boiler recovers, the cover plate 200 can be reset downward under the action of its own gravity, so that the cover plate 200 can accurately return along the original path, and the sealing convex edge 220 can abut against the bottom wall of the sealing groove 110 accurately, thereby effectively improving the sealing effect.
[0050] In addition, the vertically arranged guide column 120 can reduce the phenomenon of deviation or jamming of the cover plate 200 caused by lateral force, so that the cover plate 200 opens more smoothly, thereby improving the reliability of the boiler explosion door.
[0051] Specifically, referring to Figure 1 and Figure 6 , the upper end of the guide column 120 is connected with a positioning plate 130, the positioning plate 130 is provided with a plurality of positioning holes 131 in the circumferential direction, the guide column 120 is arranged in the positioning hole 131, and the guide column 120 and the positioning hole 131 are one-to-one corresponding. The positioning plate 130 is provided with a plurality of positioning holes 131 corresponding to the guide column 120 in the circumferential direction, which can provide more accurate and stable support for the installation and positioning of the guide column 120, so that the plurality of guide columns 120 can maintain accurate circumferential position and spacing during installation, thereby avoiding unstable movement of the cover plate 200 caused by installation deviation of the guide column 120, avoiding scratching between the cover plate 200 and the guide column 120, and improving the reliability and safety of the boiler explosion door.
[0052] In addition, the positioning plate 130 can also enhance the overall stability of the plurality of guide columns 120, prevent the guide column 120 from loosening or deviating during long-term use, further improve the smoothness of the sliding of the cover plate 200 on the guide column 120 and the sealing reliability, prolong the service life of the boiler explosion door, and improve the safety and stability of the boiler operation.
[0053] In addition, the positioning plate 130 is arranged, so that the movement stroke of the cover plate 200 in the axial direction of the guide column 120 is limited, the cover plate 200 is prevented from sliding out of the guide column 120, the automatic reset of the cover plate 200 is facilitated, the frequency of maintenance is reduced, and the convenience of use is improved.
[0054] It should be noted that the positioning plate 130 can be fixed on the guide column 120 by means of fasteners, welding or the like, which will not be described here.
[0055] Specifically, referring to Figure 1 , the guide column 120 is threadedly connected with two nuts 132, and the positioning plate 130 is arranged between the two nuts 132. The guide column 120 is threadedly connected with two nuts 132, and the positioning plate 130 is arranged between the two nuts 132, so that the height and levelness of the positioning plate 130 can be adjusted by the two nuts 132, the deviation or shaking of the positioning plate 130 during installation and use is effectively prevented, the positions of the two nuts 132 can be flexibly adjusted according to the internal pressure change of the boiler and safety requirements, the relative distance between the positioning plate 130 and the fixed seat 100 is changed, and then the opening degree of the cover plate 200 is conveniently adjusted, and the adaptability and reliability of the boiler explosion door are improved.
[0056] It can be understood that, referring to Figure 1 , the guide column 120 is sleeved with a spring 140, and the cover plate 200 can abut against the spring 140. The guide column 120 is sleeved with the spring 140, and the cover plate 200 can abut against the spring 140, so that when the internal pressure of the boiler increases and pushes the cover plate 200 to move upward, the spring 140 can absorb the impact force of the cover plate 200, reduce the impact noise, and prolong the service life; when the internal pressure of the boiler is restored, the elastic force of the spring 140 can push the cover plate 200 to adhere to the fixed seat 100, so that the cover plate 200 can be automatically reset, manual maintenance is reduced, the sealing protrusion 220 can accurately adhere to the bottom wall of the sealing groove 110, the sealing effect is improved, and the leakage of flue gas in the boiler is reduced.
[0057] It should be noted that one end of the spring 140 is fixedly connected with the guide column 120, so that when the cover plate 200 moves upward, the impact force of the cover plate 200 can be buffered and absorbed by the spring 140, the damage of the cover plate 200 is reduced, and the reliability is improved.
[0058] Specifically, referring to Figure 1The length of the spring 140 is less than the length of the guide column 120 in the axial direction of the guide column 120, and the spring 140 is arranged at the end of the guide column 120 away from the fixed base 100. By setting the length of the spring 140 to be less than the length of the guide column 120, when the cover plate 200 is opened upward, the cover plate 200 can first slide freely on the guide column 120, can respond more quickly to changes in the internal pressure of the boiler, makes the opening operation of the cover plate 200 more sensitive, and improves the dynamic response performance of the boiler explosion door. Then, the cover plate 200 abuts against the spring 140, the impact force of the cover plate 200 is absorbed by the spring 140, the cover plate 200 is prevented from being pulled out, and the reliability of the boiler explosion door is improved.
[0059] By arranging the spring 140 at the end of the guide column 120 away from the fixed base 100, when the cover plate 200 is opened upward, the cover plate 200 can quickly separate from the fixed base 100, thereby being able to consume the pressure in the boiler, and further being able to reduce the stress on the spring 140, avoid the spring 140 being continuously stressed, improve the working condition of the spring 140, and reduce the possibility of fatigue failure of the spring 140. Moreover, by arranging the spring 140 at the end of the guide column 120 away from the fixed base 100, the influence of heat radiation of the boiler on the spring 140 can be reduced, the possibility of stress relaxation of the spring 140 can be reduced, and the service life of the spring 140 can be prolonged.
[0060] In addition, by setting the length of the spring 140 to be less than the length of the guide column 120, the compressed length of the spring 140 can be effectively reduced, the space for opening the cover plate 200 upward can be increased under the same structure size, the explosion relief capacity of the boiler explosion door can be improved, the structure of the boiler explosion door is more compact, and thus the manufacturing cost of the product is reduced.
[0061] It should be noted that the first coil of the spring 140 is arranged between the two nuts 132, and the spring 140 can be fixed below the positioning plate 130 by cooperation of the two nuts 132, so that the spring 140 can be stably arranged at the end of the guide column 120 away from the fixed base 100.
[0062] It can be understood that, referring to Figure 1 The lower end of the cover plate 200 is fixedly provided with a heat-resistant layer 240, and the heat-resistant layer 240 is located in the explosion-proof opening 310. By fixedly arranging the heat-resistant layer 240 at the lower end of the cover plate 200, the erosion of high temperature on the cover plate 200 can be effectively resisted, the cover plate 200 is protected from the influence of high temperature, and the service life of the cover plate 200 is prolonged. Moreover, the heat-resistant layer 240 can also reduce the transfer of heat to the outside of the boiler, improve the thermal efficiency of the boiler, and reduce energy loss.
[0063] It should be noted that the heat-resistant layer 240 can be a concrete piece, a ceramic fiber piece, etc., which will not be described here.
[0064] The utility model embodiment makes the detailed explanation in combination with the drawing, but the utility model is not limited to the above -mentioned embodiment, still can make various changes in the knowledge range that the person skilled in the art has possesses without departing from the utility model's tenet under the precondition that the knowledge range that the person skilled in the art has possesses.
Claims
1. A boiler explosion door characterized by, The utility model relates to a sealing device for boiler explosion-proof opening, which comprises the following: A fixed seat is fixedly connected to the explosion-proof opening of the boiler, and a sealing groove is formed in the upper end of the fixed seat, which surrounds the explosion-proof opening. A guide column is fixedly connected to the fixed seat. A cover plate is arranged at the upper end of the fixed seat, and a guide hole is formed in the cover plate. The guide column is arranged in the guide hole. A sealing protruding edge is arranged at the lower end of the cover plate, which surrounds the circumference of the cover plate. The sealing protruding edge is arranged in the sealing groove and abuts against the bottom wall of the sealing groove.
2. The boiler explosion door according to claim 1, wherein The cover plate is connected to a guide sleeve, which is fixedly connected to the guide hole and the guide column is arranged in the guide sleeve.
3. The boiler explosion door according to claim 2, wherein A round corner is arranged between the inner side wall and the end face of the guide sleeve.
4. The boiler explosion door according to claim 2, wherein The number of the guide column and the guide sleeve is multiple. The multiple guide columns are evenly spaced along the circumference of the fixed seat. The guide column and the guide sleeve are one-to-one corresponding.
5. The boiler explosion door according to claim 4, wherein The multiple guide columns are arranged in the vertical direction.
6. The boiler explosion door according to claim 4, wherein A positioning plate is connected to the upper end of the guide column. The positioning plate is circumferentially provided with multiple positioning holes. The guide column is arranged in the positioning hole, and the guide column and the positioning hole are one-to-one corresponding.
7. The boiler explosion door according to claim 6, wherein Two nuts are threadedly connected to the guide column. The positioning plate is arranged between the two nuts.
8. The boiler explosion door according to claim 1, wherein The guide column is sleeved with a spring. The cover plate can abut against the spring.
9. The boiler explosion door according to claim 8, wherein In the axial direction of the guide column, the length of the spring is less than the length of the guide column, and the spring is arranged at the end of the guide column away from the fixed seat.
10. The boiler explosion door according to claim 1, wherein A heat-resistant layer is fixedly arranged at the lower end of the cover plate, which is located in the explosion-proof opening.