Fire-resistant smoke exhaust duct and method for manufacturing the same

Abstract

The application discloses a fire-resistant smoke exhaust air duct and a preparation method thereof, and comprises a metal layer and a connecting layer arranged on the inner side of the metal layer; the metal layer is composed of a plurality of metal sheets which are fixedly connected through welding; the connecting layer comprises a separation groove and a filling fabric; the separation groove is composed of a plurality of concave hexagonal structures, and the filling fabric is uniformly filled in the separation groove; the filling fabric is made of glass fiber and ceramic fiber, and ceramic whiskers / dendrites are connected to the surface of the filling fabric; the surface of the ceramic whiskers / dendrites is attached with microcapsules which have a structure that chitosan is a shell layer and a carbonate material is a capsule core; thus, the connecting strength of the outer metal layer is effectively improved, the occurrence of cracking and loosening is reduced, the filling of the filling fabric and the microcapsules effectively improves the fire suppression, and the spread of the fire is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of smoke exhaust duct, in particular to a fire-resistant smoke exhaust duct and a preparation method thereof. BACKGROUND

[0002] The smoke exhaust duct is mainly used for setting smoke prevention facilities in evacuation passages and densely populated areas, which is beneficial to the safety evacuation of personnel. The setting of the smoke exhaust duct is beneficial to the timely exhaust of toxic and high-temperature smoke generated in the fire scene, ensures the safety of the area, and eliminates the obstacles of fire extinguishing. The occurrence of fire is usually accompanied by high-temperature smoke and gas generation. The setting of the smoke exhaust duct is generally used for the exhaust of such smoke and gas, prevents the expansion and burning of the fire, and is beneficial to the direction identification of personnel in the fire scene.

[0003] However, the smoke exhaust duct in the existing device is mostly composed of a galvanized iron pipe and an inner fireproof plate, and the flanges are used to connect each section of the smoke exhaust duct. The structure of each section of the smoke exhaust duct is too heavy and has insufficient rigidity. The flanges at the connection part will be loose and even fall off in the fire scene due to the increase of temperature. SUMMARY

[0004] The present application overcomes the shortcomings of the prior art and provides a fire-resistant smoke exhaust duct and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a preparation method of a fire-resistant smoke exhaust duct, comprising the following steps:

[0006] S1: connecting metal sheets by welding to form a metal layer;

[0007] S2: connecting ceramic sheets by mechanical fixation to form an inner concave hexagonal structure, welding the inner concave hexagonal structure and the metal layer again to form a connection layer;

[0008] S3: using a filling fabric made of glass fiber and ceramic fiber, and connecting ceramic whiskers / dendrites on the surface of the filling fabric;

[0009] S4: using chitosan as a shell layer and carbonate material as a capsule core to form microcapsules by a crosslinking agent, and adding an adhesive or a glue during preparation to increase the adhesion of the shell layer, so as to obtain microcapsules that are slightly soluble in water to form a protective layer and have adhesion;

[0010] S5: using the two different filling fabrics prepared in S3 to fill the inner recessed hexagons in S2, evenly distributing the microcapsules in S4 on the filling fabrics during filling, and spraying water during filling to make the microcapsule surface slightly soluble to make it have certain adhesion and be evenly adhered to the filling fabrics, thereby forming a connection layer and fixing and connecting the connection layer and the inner shell layer.

[0011] In a preferred embodiment of the present application, in S1, the welding is selected from one of fusion welding, pressure welding or soldering.

[0012] In a preferred embodiment of the present application, in S2, the mechanical fixing mode is to use bolts or screws and the like connecting pieces for fixed connection, and the laser welding mode is used for welding the inner recessed hexagonal structure and the metal layer.

[0013] In a preferred embodiment of the present application, in S3, the glass fiber filling fabric is prepared by high-temperature melt spinning and solidification treatment process, and the branch ceramic whisker / dendrite is prepared by coating, spraying or dipping and the like.

[0014] In a preferred embodiment of the present application, in S3, the ceramic fiber filling fabric is prepared by high-temperature sintering and stretching process, and the branch ceramic whisker / dendrite is also prepared by coating or dipping and the like.

[0015] In a preferred embodiment of the present application, in S4, the microcapsules are formed by using ultrasonic stirring to make the chitosan solution coat the carbonate materials.

[0016] In a preferred embodiment of the present application, in S5, two different filling fabrics are used for filling, and two different filling fabrics are alternately and evenly filled or the two different filling fabrics are first wrapped in a structure to make the two filling fabrics wrapped and filled.

[0017] A fire-resistant smoke exhaust air duct is prepared based on a preparation method of a fire-resistant smoke exhaust air duct, and the fire-resistant smoke exhaust air duct comprises a metal layer and a connection layer arranged on the inner side of the metal layer.

[0018] The metal layer is composed of a plurality of metal sheets, and the metal sheets are fixedly connected by welding.

[0019] The connection layer comprises a separation groove and a filling fabric, the separation groove is composed of a plurality of inner recessed hexagonal structures, and the filling fabric is evenly filled in the separation groove.

[0020] The filling fabric is made of glass fiber and ceramic fiber, the surface of the filling fabric is branched with ceramic whisker / dendrite, the surface of the ceramic whisker / dendrite is attached with microcapsules, the microcapsules have a structure of chitosan as a shell layer and carbonate material as a capsule core.

[0021] In a preferred embodiment of the present application, the concave hexagonal structure is composed of four short vertical plates forming two dovetail-shaped structures, and the two long vertical plates are fixedly connected to the two dovetail-shaped structures, thereby forming a concave hexagonal structure, and the separation groove is composed of a plurality of concave hexagons.

[0022] In a preferred embodiment of the present application, the carbonate material is selected from calcium carbonate or sodium bicarbonate, which can decompose carbon dioxide at high temperature.

[0023] The present application solves the defects in the background art and has the following beneficial effects:

[0024] (1) The present application provides a fire-resistant smoke exhaust air duct and a preparation method thereof. The connection layer composed of concave hexagonal structures is used for connection, and the filling fabric and microcapsules are used for filling. Compared with the prior art, the metal layer is directly welded to the inner fireproof layer, which effectively improves the connection strength of the outer metal layer, reduces the occurrence of cracking and loosening, and effectively improves the fire suppression effect by using the filling fabric and microcapsules for filling, thereby avoiding the spread of fire.

[0025] (2) The present application provides a fire-resistant smoke exhaust air duct and a preparation method thereof. The connection layer is formed by fixedly connecting a plurality of concave hexagonal structures, and the metal layer is fixedly connected through the connection layer. Since the concave hexagonal structure has a high contact area, the friction between the contact surfaces is effectively increased, the fastening of the connection is improved, and the possibility of loosening is reduced. The stress of the concave hexagonal structure can be dispersed to a larger area, reducing the concentration of local stress and the possibility of loosening. When external force acts on the connection, the concave hexagonal structure can evenly distribute the stress and maintain the fastening of the connection. In addition, the recessed part of the concave hexagonal structure can prevent the relative movement of the connecting parts. When the connecting parts are subjected to vibration or shock, the recessed part of the concave hexagonal structure can prevent the sliding or rotation of the connecting parts, thereby reducing the possibility of loosening. The stability of the metal layer is improved, and the loosening or even falling off of the metal layer at the joint under long-term high temperature is avoided.

[0026] (3) The present application provides a fire-resistant smoke exhaust air duct and a preparation method thereof. The branch structure of the dendrite on the surface of the filling fabric increases the pore structure of the filling fabric, improves the adsorption capacity of the material for gas or liquid, and increases the surface area of the material to provide more active sites, so that the filling fabric can adhere to more microcapsules with chitosan as the shell layer and carbonate material as the core. Due to the properties of chitosan and carbonate material, when high temperature is encountered, chitosan melts to expose the core carbonate material to release carbon dioxide, thereby inhibiting the spread of fire. BRIEF DESCRIPTION OF DRAWINGS

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a perspective structural diagram of a preferred embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the three-dimensional structure of the connecting layer according to a preferred embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the connecting layer filling structure of a preferred embodiment of the present invention;

[0031] In the diagram: 1. Metal layer; 2. Metal sheet; 3. Connecting layer; 4. Ceramic sheet; 5. Filling fabric. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] As shown in Figure 1 , Figure 2 and Figure 3 , a fire-resistant smoke exhaust duct and a preparation method thereof, comprising the following steps:

[0037] S1: connecting the metal sheet 2 by welding to form a metal layer 1;

[0038] In a preferred embodiment of the present application, in S1, the welding is selected from one of fusion welding, pressure welding or soldering.

[0039] It should be noted that the welding method is preferably fusion welding. The outermost layer of the smoke exhaust duct requires high temperature resistance, corrosion resistance and fire resistance, and also requires strong structural strength. Therefore, it is made of metal material, and the metal sheet 2 is welded together by fusion welding, and the fusion welding method uses the melting point of the technology to make the metal sheet 2 welded together to form a whole, thereby enhancing the strength of the metal layer 1. During welding, first, prepare the metal sheet 2 and welding equipment needed for welding. Ensure that the surface of the metal sheet 2 is clean, free of oil and oxides; place the metal sheet 2 at the position to be connected, and use clamps or other fixing devices to fix it, ensuring the stability of the welding position; contact the welding electrode or welding wire with the metal sheet 2, and start the welding current. During welding, keep the welding electrode or welding wire in contact with the metal sheet 2, and slowly move along the connection line to make the arc melt in the welding area; on the melted metal sheet 2, use the welding wire or welding rod to supplement the welding material. The welding material should be compatible with the welded metal and have good welding performance; after welding is completed, wait for the welding area to cool down, and then check the quality of the weld. Ensure that the weld is free of cracks, pores and other defects.

[0040] S2: connecting the ceramic sheet 4 by mechanical fixation to form an inner concave hexagonal structure, and welding the inner concave hexagonal structure with the metal layer 1 again to form a connecting layer 3;

[0041] In a preferred embodiment of the present application, in S2, the mechanical fixation method is to use bolts or screws and other connecting components to fix and connect, and the welding between the inner recessed hexagonal structure and the metal layer 1 is connected by laser welding.

[0042] It should be noted that the ceramic sheet 4 is arranged in an inner recessed hexagonal structure to increase the contact area: the inner recessed hexagonal structure has a larger contact area than the flat structure. In this way, the friction between the contact surfaces can be increased, the fastening of the connection can be improved, and the possibility of loosening can be reduced. Increase the surface area of the connection: the inner recessed hexagonal structure has more connection surfaces than other shapes. In this way, the surface area of the connection can be increased, the connection can be more secure, can withstand greater force, and the risk of loosening can be reduced. Disperse stress: the inner recessed hexagonal structure can disperse stress to a larger area, reducing the concentration of local stress, thereby reducing the possibility of loosening. When external forces act on the connection, the inner recessed hexagonal structure can evenly distribute stress and maintain the fastening of the connection. Prevent relative movement: the recessed part of the inner recessed hexagonal structure can prevent the relative movement of the connecting components. When the connecting components are subjected to vibration or shock, the recessed part of the inner recessed hexagonal structure will prevent the sliding or rotation of the connecting components, thereby reducing the possibility of loosening. In this way, the stability of the metal layer 1 is increased, so that even if the metal layer 1 is in a super-high temperature state for a long time, the inner recessed hexagonal structure can still enhance the fastening of the metal layer 1, reduce the possibility of loosening, and improve the fastening.

[0043] S3: Two different filling fabrics 5 are prepared using glass fibers and ceramic fibers respectively, and ceramic whiskers / dendrites are grafted on the surfaces of the two fabrics;

[0044] In a preferred embodiment of the present application, in S3, the glass fiber preparation filling fabric 5 adopts high-temperature melt spinning and solidification treatment processes, and the ceramic whisker / dendrite grafting is prepared by coating, spraying or dipping.

[0045] It should be noted that the specific steps for preparing the glass fiber filling fabric 5 and grafting ceramic whiskers on its surface are as follows: selecting suitable glass fiber materials and preparing them into fabrics. Glass fiber fabrics can be prepared using weaving, knitting, non-woven fabric and other processes; surface treatment is performed on the glass fiber fabric to increase its surface roughness and activity, which is beneficial to the growth of ceramic whiskers / dendrites. Common surface treatment methods include acid pickling, high temperature oxidation, etc.; the precursor solution or suspension of ceramic whiskers / dendrites is coated on the surface of the glass fiber fabric. Brush coating, spraying and other methods can be used for coating; the glass fiber fabric coated with ceramic whisker / dendrite precursor is sintered. Under appropriate temperature and atmosphere conditions, the ceramic whisker / dendrite precursor will be converted into ceramic whisker / dendrite and firmly grafted on the surface of the glass fiber fabric; according to the required whisker / dendrite morphology and performance, the sintering conditions such as temperature and time are adjusted. Different ceramic materials and whisker / dendrite morphologies may require different sintering conditions; after sintering is completed, post-treatment is performed on the glass fiber fabric, such as cooling, washing, etc., to ensure that the ceramic whiskers / dendrites are firmly grafted on the surface of the fabric.

[0046] In a preferred embodiment of the present application, in S3, the ceramic fiber preparation filling fabric 5 is prepared by high temperature sintering and stretching process, and the grafted ceramic whisker / dendrite is also prepared by coating or impregnation method.

[0047] It should be noted that ceramic fiber is a kind of fiber material with excellent high temperature resistance, corrosion resistance and high strength, which can be used to prepare the filling fabric 5. The steps for grafting ceramic whiskers / dendrites on the surface are as follows: selecting suitable ceramic fiber materials, such as alumina fiber, silicon carbide fiber, etc., and preparing them into fabrics. Ceramic fiber fabrics can be prepared using weaving, knitting, non-woven fabric and other processes; surface treatment is performed on the ceramic fiber fabric to increase its surface roughness and activity, which is beneficial to the growth of ceramic whiskers / dendrites. Common surface treatment methods include acid pickling, high temperature oxidation, etc.; the ceramic fiber fabric after surface treatment is placed in the environment for the growth of ceramic whiskers / dendrites, such as high temperature furnace, and ceramic whiskers / dendrites will grow on the surface of the ceramic fiber fabric; according to the required whisker / dendrite morphology and performance, the growth conditions such as temperature, atmosphere, time, etc. are adjusted. Different ceramic materials and whisker / dendrite morphologies may require different growth conditions; after the growth of whiskers / dendrites is completed, post-treatment is performed on the ceramic fiber fabric, such as cooling, washing, etc., to ensure that the whiskers / dendrites are firmly grafted on the surface of the fabric.

[0048] S4: using chitosan as the shell layer and carbonate material as the core to form microcapsules by cross-linking agent, and adding adhesive or adhesive during preparation to increase the adhesion of the shell layer, so as to obtain microcapsules which are slightly soluble in water to form a protective layer and have adhesion;

[0049] In a preferred embodiment of the present application, in S4, the carbonate material is selected from calcium carbonate or sodium bicarbonate, etc. which can decompose carbon dioxide at high temperature, and the microcapsule is formed by using ultrasonic stirring to make the chitosan solution coat the carbonate material.

[0050] It should be noted that the method for preparing the carbonate material as the core and the chitosan as the shell of the microcapsule, and making it have certain water solubility and viscosity, and forming a protective film when the chitosan is contacted with water to prevent the carbonate material from being released too early, and having certain viscosity to adhere to the outside object is as follows: selecting calcium carbonate or sodium bicarbonate, etc. which can decompose carbon dioxide at high temperature as the core; mixing the carbonate material powder with the solvent to form a suspension. Stirring or ultrasonic treatment, etc. can be used to make the core uniformly dispersed in the solvent; dissolving the chitosan in an appropriate amount of solvent to form a chitosan solution; slowly adding the carbonate core suspension to the chitosan solution while stirring to make the carbonate core coated with chitosan to ensure uniform coating of the core; continue to stir the chitosan solution coated with the carbonate core, and gradually add a crosslinking agent such as ethylene glycol diether. The addition of the crosslinking agent will make the chitosan form a crosslinked structure, thereby forming stable microcapsules; during preparation, the concentration of chitosan in the chitosan solution and the amount of crosslinking agent added can be adjusted to control the water solubility and viscosity of the microcapsules. Increasing the concentration of chitosan and the amount of crosslinking agent added can increase the water solubility and viscosity of the microcapsules; the chitosan will form a protective film when it is contacted with water, preventing the carbonate core from being released too early. When the microcapsules are used, the chitosan will form a protective film when it is contacted with water, delaying the release of the core; in order to make the microcapsules have certain viscosity to adhere to the outside object, an adhesive or adhesive such as polyvinyl alcohol or gelatin can be added to the chitosan solution. These substances can increase the viscosity of the shell layer, making the microcapsules adhere to the outside object.

[0051] S5: using the two different filling fabrics 5 prepared in S3 to fill the inner recessed hexagon in S2, uniformly distributing the microcapsules in S4 on the filling fabric 5 during filling, and watering during filling to make the surface of the microcapsules slightly soluble to make them have certain adhesion and adhere uniformly to the filling fabric 5, thereby forming a connection layer 3 and fixing the connection layer 3 to the inner shell layer.

[0052] In a preferred embodiment of the present application, in S5, using different filling fabrics 5 for filling uses two different filling fabrics 5 to alternately fill or wraps the two different filling fabrics 5 in the structure to make the two filling fabrics 5 wrap and fill.

[0053] It should be noted that the branch ceramic whisker (also known as dendrite) is a kind of ceramic material with branch-like structure. Its structure is similar to that of a tree branch, which is composed of main crystals and branch crystals. The branch structure of the branch ceramic whisker increases its surface area, thereby improving the adsorption capacity and activity of the material. This makes the dendrite have wide application in the fields of catalysis, adsorption, separation, etc. Specifically, the structure of the branch ceramic whisker has the following effects: increasing the active surface area: the branch structure increases the surface area of the material, providing more active sites, thereby enhancing the effect of catalytic reaction; improving the adsorption capacity: the branch structure of the dendrite increases the pore structure of the material, improving the adsorption capacity of the material to gas or liquid, making it have advantages in adsorption separation, etc.; enhancing the mechanical properties: the branch structure of the branch ceramic whisker can increase the strength and toughness of the material, improve its wear resistance, corrosion resistance, etc. In summary, the structure of the branch ceramic whisker has the effects of increasing the active surface area, improving the adsorption capacity and enhancing the mechanical properties, making it have wide application prospect in the fields of catalysis, adsorption, separation, etc. Therefore, when filling the filling fabric 5, the water is sprinkled while filling, which makes the surface of the filling fabric 5 wet and the microcapsules wet, thereby making the chitosan on the surface of the microcapsules slightly soluble, producing certain adhesion, so that the surface of the filling fabric 5 is completely adhered with microcapsules, and the dendrite can effectively increase the surface area, thereby improving the adsorption capacity and activity of the material, making the filling fabric 5 adhere more microcapsules.

[0054] A fire-resistant smoke exhaust air duct is prepared based on a preparation method of a fire-resistant smoke exhaust air duct. The fire-resistant smoke exhaust air duct comprises a metal layer 1 and a connecting layer 3 arranged on the inner side of the metal layer 1.

[0055] The metal layer 1 is composed of a metal sheet 2, and the metal sheet 2 is fixedly connected by welding;

[0056] The connecting layer 3 comprises a separation groove and a filling fabric 5. The separation groove is composed of a plurality of concave hexagonal structures, and the filling fabric 5 is uniformly filled in the separation groove.

[0057] The filling fabric 5 is made of glass fiber and ceramic fiber, and the surface of the filling fabric 5 is attached with branch ceramic whiskers / dendrites. The surface of the ceramic whisker / dendrite is attached with microcapsules, and the microcapsules have a structure of chitosan as a shell layer and carbonate material as a capsule core.

[0058] In a preferred embodiment of the present application, the concave hexagonal structure is composed of four short vertical plates forming two dovetail structures, and the two dovetail structures are fixedly connected by two long vertical plates, thereby forming a concave hexagonal structure. The separation groove is composed of a plurality of concave hexagonal structures.

[0059] In a preferred embodiment of the present application, the carbonate material is selected from calcium carbonate or sodium bicarbonate, etc. which can decompose carbon dioxide at high temperature.

[0060] It should be noted that the connecting layer 3 is composed of a plurality of concave hexagons, and the plurality of concave hexagons are completely fitted and fixed together to form a complete connecting layer 3. The connecting layer 3 is fixedly connected with the external metal layer 1. The external metal layer 1 is welded together by a plurality of metal sheets 2 to form the metal layer 1. The metal layer 1 is arranged at the outermost layer. The connecting layer 3 is fixedly connected to the inner side of the metal layer 1. Then, two different fireproof filling fabrics 5 are used to fill the concave hexagons. When filling, the two different fabrics can be filled alternately, that is, one layer of glass fiber prepared filling fabric 5 and one layer of ceramic fiber prepared filling fabric 5 are filled alternately until the filling is completed. The wrapping structure can also be used to wrap the two fabrics and then fill them, that is, the two different fabrics are wrapped together and then filled. Thus, when fireproofing, the two different filling methods can make the two different fabrics play different fireproofing performances. The glass fiber has good high temperature resistance, insulation performance and corrosion resistance. The ceramic fiber has higher high temperature resistance and corrosion resistance and can remain stable at higher temperatures. The glass fiber has good fireproofing performance, can maintain structural stability at high temperatures, and has high flame retardant performance. The ceramic fiber has higher high temperature resistance and can maintain structural integrity in more extreme high temperature environments, and has excellent fireproofing performance.

[0061] The above is based on the ideal embodiment of the present application. Through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing a fire-resistant smoke exhaust duct, characterized in that, Includes the following steps: S1: Connect the metal sheets by welding to form a metal layer; S2: The ceramic sheets are connected by mechanical fixing, so that the ceramic sheets form a concave hexagonal structure. The concave hexagonal structure is then welded to the metal layer to form a connecting layer. S3: The filling fabric is made of glass fiber and ceramic fiber, and ceramic whiskers / dendrites are grafted onto the surface of the filling fabric. S4: Using chitosan as the shell and carbonate material as the core, microcapsules are formed by cross-linking agent. Adhesive is added during preparation to increase the adhesiveness of the shell, thereby obtaining microcapsules that are slightly soluble in water, form a protective layer, and have adhesiveness. S5: The concave hexagon in S2 is filled with two different filling fabrics prepared by S3. During filling, the microcapsules in S4 are evenly distributed on the filling fabric. Water is sprayed during filling to make the surface of the microcapsules slightly dissolve, so that they have a certain degree of adhesion and are evenly adhered to the filling fabric, thereby forming a connecting layer. The connecting layer is fixedly connected to the inner shell. The fire-resistant smoke exhaust duct prepared by the above preparation method includes a metal layer and a connecting layer disposed inside the metal layer, characterized in that... The metal layer is composed of several metal sheets, which are fixedly connected by welding. The connecting layer includes a partition groove and a filling fabric; the partition groove is composed of a plurality of concave hexagonal structures, and the filling fabric is uniformly filled in the partition groove; The filling fabric is made of glass fiber and ceramic fiber, and ceramic whiskers / dendritic crystals are grafted onto the surface of the filling fabric. Microcapsules are attached to the surface of the ceramic whiskers / dendritic crystals. The microcapsules have a structure with chitosan as the shell and carbonate material as the core. The concave hexagonal structure consists of two dovetail-shaped structures composed of four short vertical plates, which are set opposite each other and then fixedly connected by two long vertical plates to form a concave hexagonal structure. The partition groove is composed of several concave hexagons.

2. The method for preparing a fire-resistant smoke exhaust duct according to claim 1, characterized in that: The carbonate material is selected from calcium carbonate or sodium bicarbonate, which can decompose carbon dioxide when exposed to high temperatures.

3. The method for preparing a fire-resistant smoke exhaust duct according to claim 1, characterized in that: In S1, the welding is selected from either fusion welding or pressure welding.

4. The method for preparing a fire-resistant smoke exhaust duct according to claim 1, characterized in that: In S2, the mechanical fixing method is to use bolts or screws for fixing, and the concave hexagonal structure is welded to the metal layer by laser welding.

5. The method for preparing a fire-resistant smoke exhaust duct according to claim 1, characterized in that: In S3, the glass fiber filling fabric is prepared by high-temperature melt spinning and curing process, while the grafted ceramic whiskers / dendrites are prepared by coating or impregnation.

6. The method for preparing a fire-resistant smoke exhaust duct according to claim 1, characterized in that: In S3, the ceramic fiber filling fabric is prepared by high-temperature sintering and stretching process, and the grafted ceramic whiskers / dendritices are also prepared by coating or impregnation.

7. The method for preparing a fire-resistant smoke exhaust duct according to claim 1, characterized in that: In step S4, the microcapsules are formed by encapsulating a carbonate material with a chitosan solution using ultrasonic stirring.

8. The method for preparing a fire-resistant smoke exhaust duct according to claim 1, characterized in that: In S5, different filling fabrics are used for filling, including alternating and uniformly filling with two different filling fabrics or wrapping the two different filling fabrics together before filling.

Images