Composite filter, filter cartridge and air filtration device

Abstract

This application proposes a composite filter, filter element, and air filtration device, comprising: a pre-filter layer, a structure made of bamboo fiber material, used for pre-filtration of air; and a main filter layer, stacked and connected to the pre-filter layer, comprising one or more combinations of a glass fiber layer, a polyester fiber layer, an activated carbon layer, a meltblown nonwoven fabric layer, and an antibacterial coating. The bamboo fiber pre-filter layer, with its natural porous mesh structure, preferentially intercepts large particulate pollutants, achieving coarse filtration and reducing the load on the main filter layer. The main filter layer, through the synergistic effect of single or multiple mechanisms such as micron-level fiber interlacing, activated carbon adsorption, and electrostatic electret of meltblown fabric, deeply traps fine particles such as PM2.5 in the air after pre-filtration. The two layers work together in a progressively decreasing pore size gradient, allowing air pollutants to undergo a step-by-step purification process from coarse filtration to fine filtration, ultimately improving filtration efficiency.

Description

Technical Field

[0001] This application relates to the field of air filtration technology, and in particular to a composite filter and an air filtration device. Background Technology

[0002] Air filters are key components widely used in industry, homes, medical fields, and automobiles, playing an important role in air purification, environmental quality control, and pollution protection.

[0003] Currently, the mainstream filter elements in air filters are generally made of any single material among glass fiber, polyester fiber, and activated carbon, which has the technical problem of low filtration efficiency. Utility Model Content

[0004] This application provides a composite filter and an air filtration device to solve the problems existing in related technologies. The technical solution is as follows:

[0005] In a first aspect, embodiments of this application provide a composite filter, comprising:

[0006] A pre-filter layer, wherein the pre-filter layer is a structure made of bamboo fiber material, and the pre-filter layer is used for pre-filtering air; and

[0007] The main filter layer is stacked with the pre-filter layer. The main filter layer is one or more of the following: glass fiber layer, polyester fiber layer, activated carbon layer, meltblown nonwoven fabric layer, and antibacterial coating. The main filter layer is used to perform fine filtration on the air after it has been treated by the pre-filter layer.

[0008] In one embodiment, the composite filter further includes:

[0009] The post-filter layer, the main filter layer, and the pre-filter layer are stacked sequentially along the thickness direction of the composite filter body. The post-filter layer is made of bamboo fiber material and is used to perform post-filtration treatment on the air after it has been treated by the main filter layer.

[0010] In one embodiment, the composite filter further includes:

[0011] A PET support layer is disposed between the pre-filter layer and the main filter layer, or the PET support layer is disposed between the main filter layer and the post-filter layer.

[0012] In one embodiment, the composite filter further includes:

[0013] A first interlayer connection structure is disposed between the pre-filter layer and the main filter layer, and the first interlayer connection structure is used to fix the pre-filter layer and the main filter layer together.

[0014] The second interlayer connection structure is disposed between the post-filter layer and the main filter layer, and is used to fix the post-filter layer and the main filter layer together.

[0015] In one embodiment, when the main filter layer is a combination of glass fiber layer, polyester fiber layer, activated carbon layer, meltblown nonwoven fabric layer, and antibacterial coating, the composite filter further includes:

[0016] The third interlayer connection structure is disposed between two adjacent layers in the main filter layer, and the third interlayer connection structure is used to fix two adjacent layers in the main filter layer together.

[0017] In one embodiment, the first interlayer connection structure, the second interlayer connection structure, and the third interlayer connection structure can all be any one of a thermoplastic connection structure, an adhesive connection structure, or a suture connection structure.

[0018] In one embodiment, the cross-sectional shape of the composite filter is rectangular.

[0019] In one embodiment, the cross-sectional shape of the composite filter is a continuously folded wavy shape.

[0020] In one embodiment, the cross-sectional shape of the composite filter is a continuously folded sawtooth shape.

[0021] In one embodiment, the composite filter is cylindrical.

[0022] Secondly, embodiments of this application provide a filter element, including the aforementioned composite filter body.

[0023] Thirdly, embodiments of this application provide an air filtration device, including the aforementioned composite filter.

[0024] The advantages or beneficial effects of the above technical solutions include at least the following:

[0025] The composite layered structure of bamboo fiber pre-filter and main filter solves the problem of low filtration efficiency of traditional single materials. Specifically, the bamboo fiber pre-filter, with its natural porous mesh structure, preferentially intercepts large particulate pollutants, achieving coarse filtration and reducing the load on the main filter. The main filter, through the synergistic effect of single or multiple mechanisms such as micron-level fiber interlacing, activated carbon adsorption, and electrostatic electret of meltblown cloth, deeply traps fine particles such as PM2.5 in the air after pre-filtration. The two (bamboo fiber pre-filter and main filter) work together in a hierarchical manner with decreasing pore size gradient, allowing air pollutants to undergo a step-by-step purification process of coarse filtration and fine filtration, ultimately improving filtration efficiency. Furthermore, bamboo fiber possesses a natural longitudinal tubular pore structure, with irregular micron-sized grooves and pores distributed on its surface. This multi-level pore size distribution allows for a multi-channel diversion effect when airflow passes through, preventing concentrated airflow along a single path and thus avoiding increased local pressure drop. Simultaneously, bamboo fiber exhibits moderate rigidity, naturally forming a three-dimensional network structure during processing. The fibers are physically interlocked rather than tightly entangled to construct the filtration network. This open architecture ensures effective interception of large particulate pollutants while avoiding the rigid obstruction of airflow inherent in traditional dense filter materials. Additionally, the hemicellulose component on the surface of bamboo fiber gives it natural hydrophilicity, reducing particle adhesion and accumulation on the fiber surface and preventing increased dynamic air resistance due to particle blockage during filtration. These combined structural characteristics allow the bamboo fiber pre-filter layer to achieve coarse filtration while maintaining low and stable airflow resistance, thus achieving the dual effect of improved filtration efficiency and optimized airflow resistance. Moreover, bamboo fiber itself possesses natural antibacterial and anti-mite properties, which, combined with the main filter layer, enhance the antibacterial and anti-mildew capabilities of the composite filter, extending its service life. The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of this application will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0026] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0027] Figure 1 This is a three-dimensional structural diagram of the composite filter body of this utility model;

[0028] Figure 2 This is an exploded view of the composite filter body of this utility model;

[0029] Figure 3This is a three-dimensional structural diagram of the main filter layer in the composite filter body of this utility model;

[0030] Figure 4 This is a three-dimensional structural diagram of the filter element according to the first embodiment of the present utility model;

[0031] Figure 5 This is a three-dimensional structural diagram of the filter element according to the second embodiment of the present utility model;

[0032] Figure 6 This is a three-dimensional structural diagram of the filter element according to the third embodiment of the present utility model;

[0033] Figure 7 This is a three-dimensional structural diagram of the filter element according to the fourth embodiment of the present utility model;

[0034] Figure 8 This is a three-dimensional structural diagram of the filter element according to the fifth embodiment of the present utility model;

[0035] Figure 9 This is a three-dimensional structural diagram of the filter element according to the sixth embodiment of this utility model.

[0036] Figure Labels

[0037] 1. Composite filter body; 11. Pre-filter layer; 12. Main filter layer; 121. Glass fiber layer; 122. Polyester fiber layer; 123. Activated carbon layer; 124. Meltblown nonwoven fabric layer; 125. Antibacterial coating; 13. Post-filter layer; 14. PET support layer. Detailed Implementation

[0038] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0039] See Figures 1-3 This illustration shows a preferred embodiment of a composite filter 1, comprising:

[0040] Pre-filter layer 11, which is a structure made of bamboo fiber material, is used for pre-filtering air; and

[0041] The main filter layer 12 is stacked with the pre-filter layer 11 and is connected to the pre-filter layer 11. The main filter layer 12 is one or more of the following: glass fiber layer 121, polyester fiber layer 122, activated carbon layer 123, meltblown nonwoven fabric layer 124, and antibacterial coating 125. The main filter layer 12 is used to perform fine filtration on the air after it has been treated by the pre-filter layer 11.

[0042] The composite layered structure of bamboo fiber pre-filter 11 and main filter 12 solves the problem of low filtration efficiency of traditional single materials. Specifically, the bamboo fiber pre-filter 11, with its natural porous mesh structure, preferentially intercepts large particulate pollutants, achieving coarse filtration and reducing the load on the main filter 12. The main filter 12, through the synergistic effect of single or multiple mechanisms such as micron-level fiber interlacing, activated carbon adsorption, and electrostatic electret of meltblown cloth, deeply intercepts fine particles such as PM2.5 in the air after pre-filtration. The two (bamboo fiber pre-filter 11 and main filter 12) work together in a hierarchical manner with decreasing pore size gradient, allowing air pollutants to undergo a step-by-step purification process of coarse filtration and fine filtration, ultimately improving filtration efficiency. Furthermore, bamboo fiber possesses a natural longitudinal tubular pore structure, with irregular micron-sized grooves and pores distributed on its surface. This multi-level pore size distribution allows for a multi-channel diversion effect when air flows through it, preventing concentrated airflow through a single path and thus avoiding increased local pressure drop. Simultaneously, bamboo fiber exhibits moderate rigidity, naturally forming a three-dimensional network structure during processing. The fibers are physically interlocked rather than tightly entangled to construct the filtration network. This open architecture ensures effective interception of large particulate pollutants while avoiding the rigid obstruction of airflow inherent in traditional dense filter materials. Additionally, the hemicellulose component on the surface of bamboo fiber gives it natural hydrophilicity, reducing particle adhesion and accumulation on the fiber surface and preventing increased dynamic air resistance due to particle blockage during filtration. These combined structural characteristics allow the bamboo fiber pre-filter layer 11 to achieve coarse filtration while maintaining low and stable airflow resistance, thus achieving the dual effect of improved filtration efficiency and optimized airflow resistance. Moreover, bamboo fiber itself possesses natural antibacterial and anti-mite properties. Combined with the main filter layer 12, this enhances the antibacterial and anti-mildew capabilities of the composite filter body 1, extending its service life.

[0043] It should be noted that the glass fiber layer 121 forms a physical interception barrier through the dense interlaced structure of micron-sized fibers, which can effectively capture suspended particulate matter; the polyester fiber layer 122 constructs a three-dimensional filtration network with the flexibility of fibers to achieve gradient interception of particulate matter; the activated carbon layer 123 uses its well-developed porous surface structure to adsorb gaseous pollutants and odor molecules; the meltblown nonwoven fabric layer 124 enhances the capture ability of submicron-sized particles by relying on the electrostatic effect generated by the electret; and the antibacterial coating 125 inhibits bacterial reproduction by destroying the microbial cell structure through active ingredients. With the main filter layer 12 composed of glass fiber layer 121, polyester fiber layer 122, activated carbon layer 123, meltblown nonwoven fabric layer 124, and antibacterial coating 125, the functional filter layers work together to form a comprehensive purification system from coarse filtration to fine filtration and from physical interception to chemical treatment, so that the composite filter 1 has multiple functions of particulate matter filtration, gaseous pollutant adsorption, and microbial inhibition.

[0044] It should be noted that the adjacent layers in the main filter layer 12 are also stacked along the thickness direction of the composite filter body 1.

[0045] It is understood that bamboo fiber can be processed into non-woven fabric using chopped bamboo pulp fiber, refined bamboo fiber, and needle punching / wet forming processes.

[0046] It is understood that the antibacterial coating 125 can be made of any one of the following materials: silver ions, chitosan, natural tea polyphenols, etc.

[0047] See Figures 1-2 In one embodiment, the composite filter 1 further includes:

[0048] The post-filter layer 13, the main filter layer 12 and the pre-filter layer 11 are stacked sequentially along the thickness direction of the composite filter body 1. The post-filter layer 13 is connected to the main filter layer 12. The post-filter layer 13 is a structure made of bamboo fiber material. The post-filter layer 13 is used to perform post-filtration treatment on the air after it has been treated by the main filter layer 12. By adding a bamboo fiber post-filter layer 13 to the composite filter 1, a three-stage gradient filtration system is formed by stacking it sequentially with the main filter layer 12 and the pre-filter layer 11 along the thickness direction. The post-filter layer 13 utilizes the natural porous structure of bamboo fiber to perform terminal purification of the air treated by the main filter layer 12. Its three-dimensional mesh fiber structure can not only capture the fine particles that escape from the main filter layer 12, but also balance the airflow resistance through the loose pore distribution between the fibers. At the same time, the antibacterial properties of bamboo fiber form a microbial inhibition barrier at the final air outlet, forming a dual antibacterial protection with the bamboo fiber pre-filter layer 11. This allows the overall composite filter 1 to achieve a linear increase in filtration efficiency while maintaining low air resistance characteristics, and extends the service life of the composite filter 1 through the reasonable distribution of pollutant interception load between layers.

[0049] In one embodiment, the composite filter 1 further includes:

[0050] A PET support layer 14 is disposed between the pre-filter layer 11 and the main filter layer 12, connecting the pre-filter layer 11 and the main filter layer 12; alternatively, the PET support layer 14 is disposed between the main filter layer 12 and the post-filter layer 13, connecting the main filter layer 12 and the post-filter layer 13. Thus, by placing the PET support layer 14 between the pre-filter layer 11 and the main filter layer 12, or between the main filter layer 12 and the post-filter layer 13, the high strength and rigidity of the PET material provide stable physical support for the composite filter 1, preventing structural deformation or interlayer displacement of each functional filter layer under airflow impact. Simultaneously, the unique mesh-like perforated structure of the PET support layer 14 maintains unobstructed airflow channels to control overall wind resistance, and guides airflow evenly through each functional filter layer through a precisely designed pore size distribution, avoiding a decrease in filtration efficiency caused by local airflow short-circuiting. Therefore, while ensuring the overall structural stability of the composite filter 1, the comprehensive performance of the multi-layer composite filter structure is optimized.

[0051] In one embodiment, the composite filter 1 further includes:

[0052] The first interlayer connection structure is disposed between the pre-filter layer 11 and the main filter layer 12. The first interlayer connection structure is used to fix the pre-filter layer 11 and the main filter layer 12 together.

[0053] The second interlayer connection structure is located between the post-filter layer 13 and the main filter layer 12, and is used to fix the post-filter layer 13 and the main filter layer 12 together. Thus, by setting the first interlayer connection structure between the pre-filter layer 11 and the main filter layer 12, and the second interlayer connection structure between the main filter layer 12 and the post-filter layer 13, a stable interlayer connection is formed between the functional filter layers. This effectively prevents the interlayer separation or misalignment of the composite filter 1 due to airflow impact or mechanical vibration during use, ensuring that the multi-layer functional filter layers always maintain the designed relative positional relationship and filtration gradient. At the same time, the setting of the first and second interlayer connection structures ensures close contact between the functional filter layers to achieve the optimal filtration path for step-by-step interception of pollutants, while avoiding a decrease in filtration efficiency due to interlayer displacement, thereby significantly improving the structural reliability and long-term stability of the composite filter 1.

[0054] In one embodiment, when the main filter layer 12 is a combination of glass fiber layer 121, polyester fiber layer 122, activated carbon layer 123, meltblown nonwoven fabric layer 124, and antibacterial coating 125, the composite filter body 1 further includes:

[0055] The third interlayer connection structure is located between two adjacent layers in the main filter layer 12, and is used to fix the two adjacent layers in the main filter layer 12 together. Thus, by setting the third interlayer connection structure between adjacent functional layers in the main filter layer 12, the filter media with different properties, such as the glass fiber layer 121, polyester fiber layer 122, activated carbon layer 123, meltblown nonwoven fabric layer 124, and antibacterial coating 125, form a stable interlayer bond. This effectively prevents interface separation or structural deformation of the multi-layer functional filter layers due to differences in physical properties during use, ensuring that each functional filter layer maintains the designed synergistic filtration relationship in the composite filter body 1. At the same time, while maintaining the structural integrity of each component within the main filter layer 12, this third interlayer connection structure ensures the effective connection of pollutant interception, adsorption, and antibacterial functions among the multi-layer composite filter media, thereby significantly improving the overall structural stability and multi-functional synergistic filtration effect of the composite filter body 1.

[0056] In one embodiment, the first, second, and third interlayer connection structures can all be any one of the following: hot-melt connection, adhesive connection, or stitched connection. Thus, by configuring the first, second, and third interlayer connection structures to selectively employ hot-melt, adhesive, or stitched connections, the connection methods between the functional filter layers of the composite filter 1 offer process adaptability flexibility. Hot-melt connection achieves seamless interface bonding through material self-adhesion, avoiding adhesive contamination; adhesive connection can adapt to the high-strength bonding requirements between different material layers; and stitched connection provides reliable mechanical reinforcement. The selective application of these three connection methods optimizes the interlayer bonding strength according to the material characteristics of different functional filter layers and balances connection efficiency and cost according to production process requirements. This ensures that the composite filter 1 maintains stable interlayer structural integrity under long-term airflow impact and temperature and humidity changes, thereby comprehensively improving the reliability and service life of the filter.

[0057] In one embodiment, the composite filter 1 has a rectangular cross-sectional shape, that is, the composite filter 1 is flat, so that the composite filter 1 can be used for HVAC air filters and air purifier filters.

[0058] In one embodiment, the cross-sectional shape of the composite filter 1 is a continuous folded wave shape, making the composite filter 1 suitable for HEPA filters or high airflow filters.

[0059] In one embodiment, the composite filter 1 has a continuously folded sawtooth cross-sectional shape, making it suitable for HEPA filters or high-flow-rate filters.

[0060] In one embodiment, the composite filter 1 is cylindrical, making it suitable for use as an industrial dust removal filter element.

[0061] In one embodiment, the composite filter 1 is in the form of other irregular shapes, so that the composite filter 1 can be applied to vehicle air conditioning filters, mask filters, etc.

[0062] In summary, the composite filter 1 of this utility model has at least the following advantages:

[0063] The filtration efficiency can reach G4~MERV13 levels, with a PM2.5 filtration rate of >85% and a PM0.3 efficiency of ≥95% through composite design;

[0064] Wind resistance is less than 300Pa (under normal wind speed conditions);

[0065] Antibacterial rate >99% (targeting Escherichia coli, Staphylococcus aureus, etc.);

[0066] Without integrating the glass fiber layer 121 and the polyester fiber layer 122, the overall material is biodegradable, environmentally friendly and non-toxic, and meets RoHS and REACH regulations.

[0067] See Figures 4-9 This invention illustrates a preferred embodiment of a filter element comprising the aforementioned composite filter body 1.

[0068] The filter element of this utility model, by adopting the aforementioned composite filter body 1, also solves the problem of low filtration efficiency of traditional single materials through the composite layered structure of bamboo fiber pre-filter layer 11 and main filter layer 12. Specifically, the bamboo fiber pre-filter layer 11, with its natural porous mesh structure, preferentially intercepts large particulate pollutants, achieving coarse filtration and reducing the load on the main filter layer 12; the main filter layer 12, through the synergistic effect of single or multiple mechanisms such as micron-level fiber interlacing, activated carbon adsorption, and electrostatic electret of meltblown cloth, deeply intercepts fine particles such as PM2.5 in the air after pre-filtration. The two (bamboo fiber pre-filter layer 11 and main filter layer 12) cooperate in a hierarchical manner with decreasing pore size gradient, so that air pollutants undergo a step-by-step purification process of coarse filtration and fine filtration, ultimately achieving improved filtration efficiency. Furthermore, bamboo fiber possesses a natural longitudinal tubular pore structure, with irregular micron-sized grooves and pores distributed on its surface. This multi-level pore size distribution allows for a multi-channel diversion effect when air flows through it, preventing concentrated airflow through a single path and thus avoiding increased local pressure drop. Simultaneously, bamboo fiber exhibits moderate rigidity, naturally forming a three-dimensional network structure during processing. The fibers are physically interlocked rather than tightly entangled to construct the filtration network. This open architecture ensures effective interception of large particulate pollutants while avoiding the rigid obstruction of airflow inherent in traditional dense filter materials. Additionally, the hemicellulose component on the surface of bamboo fiber gives it natural hydrophilicity, reducing particle adhesion and accumulation on the fiber surface and preventing increased dynamic air resistance due to particle blockage during filtration. These combined structural characteristics allow the bamboo fiber pre-filter layer 11 to achieve coarse filtration while maintaining low and stable airflow resistance, thus achieving the dual effect of improved filtration efficiency and optimized airflow resistance. Moreover, bamboo fiber itself possesses natural antibacterial and anti-mite properties. Combined with the main filter layer 12, this enhances the antibacterial and anti-mildew capabilities of the composite filter body 1, extending its service life.

[0069] A preferred embodiment of the present invention provides an air filtration device, including the aforementioned composite filter 1.

[0070] The air filtration device of this utility model, by employing the aforementioned composite filter 1, solves the problem of low filtration efficiency of traditional single materials through the composite layered structure of bamboo fiber pre-filter layer 11 and main filter layer 12. Specifically, the bamboo fiber pre-filter layer 11, with its natural porous mesh structure, preferentially intercepts large particulate pollutants, achieving coarse filtration and reducing the load on the main filter layer 12; the main filter layer 12, through the synergistic effect of single or multiple mechanisms such as micron-level fiber interlacing, activated carbon adsorption, and meltblown cloth electrostatic electret, deeply intercepts fine particles such as PM2.5 in the air after pre-filtration. The two (bamboo fiber pre-filter layer 11 and main filter layer 12) work together in a hierarchical manner with decreasing pore size gradient, allowing air pollutants to undergo a step-by-step purification process of coarse filtration and fine filtration, ultimately achieving improved filtration efficiency. Furthermore, bamboo fiber possesses a natural longitudinal tubular pore structure, with irregular micron-sized grooves and pores distributed on its surface. This multi-level pore size distribution allows for a multi-channel diversion effect when air flows through it, preventing concentrated airflow through a single path and thus avoiding increased local pressure drop. Simultaneously, bamboo fiber exhibits moderate rigidity, naturally forming a three-dimensional network structure during processing. The fibers are physically interlocked rather than tightly entangled to construct the filtration network. This open architecture ensures effective interception of large particulate pollutants while avoiding the rigid obstruction of airflow inherent in traditional dense filter materials. Additionally, the hemicellulose component on the surface of bamboo fiber gives it natural hydrophilicity, reducing particle adhesion and accumulation on the fiber surface and preventing increased dynamic air resistance due to particle blockage during filtration. These combined structural characteristics allow the bamboo fiber pre-filter layer 11 to achieve coarse filtration while maintaining low and stable airflow resistance, thus achieving the dual effect of improved filtration efficiency and optimized airflow resistance. Moreover, bamboo fiber itself possesses natural antibacterial and anti-mite properties. Combined with the main filter layer 12, this enhances the antibacterial and anti-mildew capabilities of the composite filter body 1, extending its service life.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0073] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A composite filter element, characterized in that, include: A pre-filter layer, which is a structure made of bamboo fiber material, is used for pre-filtering air. as well as The main filter layer is stacked with the pre-filter layer and is connected to the pre-filter layer. The main filter layer is one or more of the following: glass fiber layer, polyester fiber layer, activated carbon layer, meltblown nonwoven fabric layer, and antibacterial coating. The main filter layer is used to perform fine filtration on the air after it has been treated by the pre-filter layer.

2. The composite filter body according to claim 1, characterized in that, The composite filter also includes: The post-filter layer, the main filter layer, and the pre-filter layer are stacked sequentially along the thickness direction of the composite filter body. The post-filter layer is connected to the main filter layer. The post-filter layer is a structure made of bamboo fiber material. The post-filter layer is used to perform post-filtration treatment on the air after it has been treated by the main filter layer.

3. The composite filter body according to claim 2, characterized in that, The composite filter also includes: A PET support layer is disposed between the pre-filter layer and the main filter layer, and the PET support layer connects the pre-filter layer and the main filter layer; or, the PET support layer is disposed between the main filter layer and the post-filter layer, and the PET support layer connects the main filter layer and the post-filter layer.

4. The composite filter body according to claim 2, characterized in that, The composite filter also includes: A first interlayer connection structure is disposed between the pre-filter layer and the main filter layer, and the first interlayer connection structure is used to fix the pre-filter layer and the main filter layer together. The second interlayer connection structure is disposed between the post-filter layer and the main filter layer, and is used to fix the post-filter layer and the main filter layer together.

5. The composite filter body according to claim 4, characterized in that, When the main filter layer is a combination of glass fiber layer, polyester fiber layer, activated carbon layer, meltblown nonwoven fabric layer, and antibacterial coating, the composite filter further includes: The third interlayer connection structure is disposed between two adjacent layers in the main filter layer, and the third interlayer connection structure is used to fix two adjacent layers in the main filter layer together.

6. The composite filter body according to claim 5, characterized in that, The first interlayer connection structure, the second interlayer connection structure, and the third interlayer connection structure can all be any one of the following: heat fusion connection structure, adhesive connection structure, and suture connection structure.

7. The composite filter body according to claim 1, characterized in that, The cross-sectional shape of the composite filter is rectangular.

8. The composite filter body according to claim 1, characterized in that, The cross-sectional shape of the composite filter is a continuously folded wavy shape or a continuously folded sawtooth shape.

9. A filter element, characterized in that, The composite filter includes any one of claims 1-8.

10. An air filtration device, characterized in that, The composite filter includes any one of claims 1-8.

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