Air filter manufacturing method and air filter

Abstract

This invention provides a method for preparing an air filter element and the air filter element itself. The preparation method includes the following steps: providing a multi-layer composite nonwoven fabric; processing the nonwoven fabric to form a fine filter block; sealing the sides of the fine filter block to form the fine filter module; polyurethane foam molding to form a coarse filter module; connecting the fine filter module and the coarse filter module to form an air filter element. This invention uses nonwoven fabric as the filter medium of the air filter element, which has the characteristics of high air permeability, low resistance, and washability. Furthermore, it exhibits stable performance and excellent weather resistance under operating conditions of -40°C to 120°C, thereby extending the service life of the air filter element. The side sealing process reinforces and seals the filter, preventing leakage and supporting the filter medium, ensuring the dimensional stability of the air filter element.

Description

Technical Field

[0001] This invention relates to the field of physics, and more particularly to air filtration devices, especially a method for preparing an air filter element and the air filter element itself. Background Technology

[0002] Traditional passenger car engine purification filters use filter media made of wood pulp fiber impregnated with resin. They have low dust holding capacity and filtration accuracy, poor water resistance and weather resistance, and generally need to be replaced every 10,000km to 20,000km. They are not washable and have a short lifespan, which does not conform to the future trend of environmental protection and long service life. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing an air filter element and an air filter element, which solves the problems of existing air purification filter elements using wood pulp fiber as the filter medium, such as low dust holding capacity, low filtration accuracy, poor water resistance and weather resistance, non-washability, and short lifespan.

[0004] In a first aspect, the present invention provides a method for preparing an air filter element, comprising the following steps: providing a multi-layer composite nonwoven fabric; processing the nonwoven fabric to form a fine filter block; sealing the sides of the fine filter block to form the fine filter module; polyurethane foam molding to form a coarse filter module; and connecting the fine filter module and the coarse filter module to form an air filter element.

[0005] In this invention, non-woven fabric is used as the filter medium of the air filter element. It has the characteristics of high air permeability, low resistance, and washability. Moreover, it has good performance stability and excellent weather resistance under operating conditions of -40°C to 120°C, thereby extending the service life of the air filter element. The side sealing process is used to reinforce and seal the filter element, which can prevent leakage and support the filter medium of the air filter element, ensuring the dimensional stability of the air filter element.

[0006] In one implementation of the first aspect, the process of forming a fine filter block by processing the nonwoven fabric includes the following steps: indenting the nonwoven fabric; injecting hot melt adhesive lines into both sides of the indented nonwoven fabric to evenly distribute the indented nonwoven fabric into multiple filter cavities with equal filtration areas, forming filter paper blocks; dividing and connecting adjacent filter cavities by support ribs formed by the hot melt adhesive lines; and continuously and uninterruptedly folding the filter paper blocks to form the fine filter block.

[0007] In this implementation, the non-woven fabric (the filter medium of the air filter) is coated with glue on both sides to form multiple evenly distributed filter cavities. This optimizes the air intake channel, reduces air intake resistance, and facilitates the even distribution of gas on the inlet / outlet surfaces of the filter medium. This ensures the strength and rigidity of the air filter, as well as the uniform dust holding capacity and low resistance of the filter medium, thereby ensuring the stable performance of the air filter.

[0008] In one implementation of the first aspect, before indenting the nonwoven fabric, the process of forming a fine filter block by processing the nonwoven fabric further includes: leveling the nonwoven fabric; the indentation process of the nonwoven fabric includes: indenting the nonwoven fabric after leveling.

[0009] In one implementation of the first aspect, forming the fine filter block includes: cutting the filter paper block that has been repeatedly folded to obtain the fine filter block.

[0010] In one implementation of the first aspect, the edge sealing treatment of the side of the fine filter block includes: bonding PET edge strips to the side of the fine filter block.

[0011] In one implementation of the first aspect, prior to the step of connecting the fine filter module and the coarse filter module, the method for preparing the air filter element further includes: sealing the fine filter module; the step of connecting the fine filter module and the coarse filter module includes: connecting the sealed fine filter module and the coarse filter module.

[0012] In this implementation, the air filter element's waterproof performance is ensured by sealing the fine filter module.

[0013] In one implementation of the first aspect, connecting the fine filter module and the coarse filter module includes: bonding the fine filter module and the coarse filter module with hot melt adhesive.

[0014] In one implementation of the first aspect, the side of the coarse filter module away from the fine filter module has a wavy shape.

[0015] In this implementation, the side of the coarse filter module away from the fine filter module is designed with a concave-convex wave shape, so that sound waves can be absorbed and reflected in the groove, thereby achieving the effect of noise reduction or reducing echo, and thus improving the purity of the sound.

[0016] Secondly, the present invention provides an air filter element, which is prepared by the air filter element preparation method described above.

[0017] As described above, the method for preparing the air filter element and the air filter element of the present invention have the following beneficial effects:

[0018] (1) Compared with the prior art, the air filter prepared by the air filter preparation method provided by the present invention first filters out large dust particles through the coarse filter module to prevent large dust particles from accumulating on the surface of the fine filter module during the process of filtering dust in the air. At the same time, the coarse filter module can also reduce the air flow rate, thereby preventing the fine filter module from being broken down and thus extending the service life of the air filter. Then, the fine filter module performs precise filtration of tiny pollutants. The use of graded filtration increases the dust holding capacity and ensures that the air filter maintains low resistance and saves energy during use.

[0019] (2) In the filtration process, the present invention can also achieve the function of noise reduction; specifically, the coarse filtration module is used to absorb sound and reduce noise first, and then the fine filtration module is used to ensure the effect of noise reduction. Attached Figure Description

[0020] Figure 1 The flowchart shown is a method for preparing the air filter element of the present invention in one embodiment.

[0021] Figure 2 The flowchart shown is a process for processing nonwoven fabric to form a fine filter block according to one embodiment of the present invention.

[0022] Figure 3 The diagram shown is a split view of an embodiment of the air filter element of the present invention.

[0023] Figure 4 The image shown is a partial cross-sectional view of an embodiment of the air filter element of the present invention.

[0024] Figure 5 The image shown is a cross-sectional view of an embodiment of the air filter element of the present invention.

[0025] Figure 6 The diagram shown is a structural schematic of the coarse filter module of the present invention in one embodiment.

[0026] Figure 7 The diagram shows a three-dimensional mesh structure of the internal structure of the coarse filter module of the present invention in one embodiment. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0028] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0029] As mentioned in the background section, traditional passenger vehicle engine air purification filters use wood pulp fiber impregnation as the filter medium. Because wood pulp fiber has a coarse fiber diameter, small surface porosity, high intake resistance, and low dust holding capacity, using it as a filter medium results in high intake noise, leading to an uncomfortable driving experience. Furthermore, traditional wood pulp fiber filters have short lifespans, low efficiency, and are prone to premature engine wear. Wood pulp fiber filter media also has poor weather resistance; in windy, sandy, rainy, or snowy environments, the filter is easily deformed and bent after getting damp. This deformation affects the filter's flow channels, resistance, and other performance indicators, and makes it susceptible to puncture. Additionally, poor sealing on the sides of existing filters can easily lead to leakage in bumpy, unpaved road environments, which does not adequately protect the engine. Existing filters cannot be washed with water, have a short lifespan, and require frequent replacement (generally every 10,000 km to 20,000 km).

[0030] Furthermore, in the automotive industry, as users' demands for overall vehicle comfort increase, OEMs are being forced to impose increasingly stringent requirements on vehicle noise, including intake system noise. New energy vehicles (range-extended hybrids, hybrids, and pure electric vehicles) are increasingly incorporating comfort and safety features, leading to a decrease in available space in the engine compartment. This results in less space for installing wideband mufflers, resonant boxes, and other noise reduction components. The contradiction between the reduced space for noise reduction and the need to improve vehicle noise levels is becoming increasingly significant. Improving vehicle noise levels requires space to install noise reduction components, but the increasingly compact engine compartment space does not allow for the installation of too many.

[0031] See Figures 1 to 7This invention uses non-woven fabric as the filter medium for the air filter element. Compared with wood pulp fiber, it has the advantages of being lightweight, water-repellent (wood pulp fiber will swell when it absorbs water), having long fibers, small diameter, high surface porosity, being less prone to clogging, having high dust holding capacity per pass, high air permeability, low resistance, and being washable. Furthermore, it exhibits stable performance and excellent weather resistance under operating conditions of -40°C to 120°C, ensuring that the filter paper will not bend, deform, or fold throughout the entire lifespan of the air filter element. This invention also achieves noise reduction. Specifically, sound absorption and noise reduction are achieved first through a coarse filter module, and then through a fine filter module to ensure the noise reduction effect. Simultaneously, by designing the side of the coarse filter module away from the fine filter module with a concave-convex wave shape, sound waves can be absorbed and reflected within the grooves, thereby achieving noise reduction or reducing echoes, thus improving sound purity. This effectively alleviates the contradiction between reducing the space for noise reduction in the engine compartment and increasing vehicle noise levels.

[0032] The technical solutions of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] like Figure 1 As shown, in one embodiment, the method for preparing the air filter element of the present invention includes the following steps:

[0034] Step S1: Provide a multi-layer composite nonwoven fabric.

[0035] It should be noted that this non-woven fabric is used as the filter medium for the air filter element.

[0036] Non-woven fabric, also known as high-breathability synthetic fiber, has a dust holding capacity that is more than 4 times higher than that of filter paper for the same filtration area. The air permeability of all-chemical fiber filter paper is more than 2 times higher than that of traditional wood pulp fiber filter paper.

[0037] Step S2: Process the nonwoven fabric to form a fine filter block.

[0038] like Figure 2 As shown, in one embodiment, the process of treating the nonwoven fabric to form a fine filter block includes the following steps:

[0039] Step S21: Indent the nonwoven fabric.

[0040] In one embodiment, before indenting the nonwoven fabric, the process of forming a fine filter block by processing the nonwoven fabric further includes: flattening the nonwoven fabric.

[0041] In this embodiment, the indentation treatment of the nonwoven fabric includes: indenting the nonwoven fabric after it has been leveled.

[0042] In one embodiment, the nonwoven fabric roll is leveled by pressure rollers and then indented.

[0043] Specifically, the nonwoven fabric roll after leveling is indented according to the fold height of the filter medium.

[0044] It should be noted that the specific pleat height of the filter medium is not a limiting factor of the present invention. In practical applications, it can be determined according to the specific application scenario.

[0045] In one embodiment, a reciprocating inserter is used for indentation.

[0046] Step S22: Apply hot melt adhesive lines to both sides of the nonwoven fabric after the embossing treatment, so that the nonwoven fabric after the embossing treatment is evenly distributed into multiple filter cavities with equal filter areas to form filter paper blocks.

[0047] It should be noted that in this embodiment, by performing double-sided glue injection on the non-woven fabric after the embossing treatment, compared with the single-sided glue injection in the prior art, the average distribution of gas on the inlet / outlet surface of the filter medium is ensured, the strength and stiffness of the air filter element are guaranteed, and the dust holding capacity of the filter medium is uniform and the resistance is low, thereby ensuring the stable performance of the air filter element.

[0048] In one embodiment, a continuous and uninterrupted glue injection process is used to inject hot melt glue lines into both sides of the non-woven fabric after the indentation treatment, so that the inflow surface (the side where dirty air is located) and the outflow surface (the side where clean air is located) of the filter medium are evenly distributed into multiple filter cavities of equal area, ensuring the strength and stiffness of the air filter element folds, and ensuring that the filter medium has uniform dust holding capacity and low resistance.

[0049] It should be noted that the double-sided injection molding process makes the filter medium of the air filter element an integrated structure, ensuring the stability of the air filter element's dimensions and excellent assembly with the intake assembly. At the same time, the double-sided injection molding process uniformly distributes the non-woven filter medium, dividing the filter medium of the entire air filter element into several filter cavities with equal filtration areas. Each filter cavity is divided and connected by supporting ribs, which can effectively prevent phenomena such as folding, bending, and collapse during use.

[0050] In this embodiment, adjacent filter cavities are divided and connected by support ribs formed by the hot melt adhesive lines.

[0051] It should be noted that the uninterrupted hot melt adhesive line forms a connecting rib on the surface after curing, while the hot melt adhesive line that separates each filter cavity is called a support rib; the hot melt adhesive line fixing band on the inlet and outlet surfaces of the filter medium supports and prevents the filter medium from folding, ensuring that the dirt holding capacity of each filter cavity can be evenly distributed.

[0052] The integrated structure of the filter media and hot melt adhesive line results in high air filter strength and facilitates modular arrangement; the modular filter paper manufacturing process can perfectly replace the original material air filter.

[0053] Step S23: Continuously and uninterruptedly fold the filter paper block to form the fine filter block.

[0054] In one embodiment, forming the fine filter block includes: cutting the filter paper block that has been repeatedly folded to obtain the fine filter block.

[0055] Step S3: Seal the sides of the fine filter block to form the fine filter module.

[0056] In one embodiment, the edge sealing treatment of the side of the fine filter block includes: bonding PET edge strips to the side of the fine filter block.

[0057] It should be noted that PET, commonly known as polyester resin, is a crystalline saturated polyester.

[0058] It should be noted that the aforementioned side sealing process can prevent leakage, enabling the air filter to be used in various road conditions. At the same time, it can support the air filter media and ensure dimensional stability.

[0059] It should be noted that the aforementioned fine filtration module mainly uses fiber filtration. Its filtration mechanism is a combination of effects including inertial impaction, interception, and diffusion. Its interception efficiency for particles larger than 1μm is no less than 90%.

[0060] Inertial impaction: Heavy particulate pollutants deviate from the streamline under inertial action and collide with the fiber and are trapped (for particles larger than 1 μm).

[0061] Interception: As particulate pollutants move with the streamlines, they collide with the fibers and are trapped because the particle size is larger than the distance between the streamlines and the fibers (for particles with a diameter of 0.1 μm to 5 μm).

[0062] Diffusion: Tiny contaminants (particles smaller than 1 μm) are trapped on the fiber due to Brownian motion.

[0063] Step S4: Polyurethane foam molding to form a coarse filter module.

[0064] It should be noted that this coarse filter module can prevent the fine filter module from being damaged, increases the ash storage capacity, and plays a role in noise reduction.

[0065] The coarse filter module, also known as the sound absorption and noise reduction module, is made of polyurethane foam material foamed in a specific mold through a special process. The material has a water-repellent effect (polyurethane material can also be frequently used as a waterproof material for roofs). It can filter and intercept large particles larger than 10um. The main filtration mechanism is pore filtration (sieving).

[0066] In one embodiment, the side of the coarse filter module away from the fine filter module has a wavy shape (e.g., Figures 3 to 6 (As shown).

[0067] It should be noted that by designing the side of the coarse filter module away from the fine filter module as a concave-convex wave shape, sound waves can be absorbed and reflected within the grooves, thereby achieving the effect of noise reduction or echo reduction, and thus improving the purity of the sound.

[0068] In one embodiment, the coarse filter module is an overall honeycomb porous medium, which can reduce the intake noise of the air filter, filter large dust particles, and prevent the intake air passage from becoming blocked.

[0069] It should be noted that the main material of the aforementioned coarse filter module is polyurethane foam sponge, which has a three-dimensional mesh-like porous structure (e.g., Figure 4 and Figure 7 As shown, it has a large number of interconnected pores. When sound waves enter the interior, they cause air vibrations. Due to the viscous resistance of the air and the friction between the air and the pore walls, a considerable portion of the sound energy is converted into heat energy and consumed. When the air is adiabatically compressed, heat exchange occurs continuously between the air and the pore walls. Due to heat conduction, some sound energy is also converted into heat energy, thereby reducing noise and effectively mitigating the contradiction between the reduction of noise reduction space in the car engine compartment and the increase in vehicle noise level.

[0070] Specifically, the coarse filter module functions as follows:

[0071] (1) Sound absorption and noise reduction;

[0072] (2) Reduce airflow velocity to protect the fine filter module from being damaged;

[0073] (3) Filter large particles to prevent dust from accumulating on the surface of the fine filter module and improve the life of the fine filter module;

[0074] (4) Washable;

[0075] (5) Large dust particles are desorbed by vibration.

[0076] Step S5: Connect the fine filter module and the coarse filter module to form an air filter element.

[0077] In one embodiment, prior to the step of connecting the fine filter module and the coarse filter module, the method for preparing the air filter element further includes: sealing the fine filter module.

[0078] In one embodiment, polyurethane is used to seal the fine filtration module.

[0079] Specifically, polyurethane is injected into the processing cavity, and then the fine filter module is placed inside. After the polyurethane cures, the fine filter module is sealed.

[0080] It should be noted that the polyurethane here acts as a sealing ring.

[0081] In this embodiment, connecting the fine filter module and the coarse filter module includes connecting the sealed fine filter module and the coarse filter module.

[0082] In one embodiment, connecting the fine filter module and the coarse filter module includes bonding the fine filter module and the coarse filter module with hot melt adhesive.

[0083] It should be noted that the scope of protection of the air filter preparation method described in this invention is not limited to the order of steps listed in this embodiment. Any solution achieved by adding, subtracting, or replacing steps in the prior art based on the principles of this invention is included within the scope of protection of this invention.

[0084] In one embodiment, the air filter element of the present invention is prepared by the air filter element preparation method described above.

[0085] It should be noted that the working principle of this air filter is as follows:

[0086] First, the coarse filter module absorbs sound and reduces noise, filtering out large dust particles and preventing them from accumulating on the surface of the fine filter module. Simultaneously, this coarse filter module also reduces airflow velocity, preventing the fine filter module from being damaged and thus extending the lifespan of the air filter element. Then, the fine filter module precisely filters out minute pollutants, ensuring effective noise reduction. This multi-stage filtration increases dust capacity, ensuring consistently low resistance and energy savings during air filter use.

[0087] It should be noted that, in conjunction with the above, the air filter element provided by the present invention adopts graded filtration (specifically, graded filtration through a coarse filter module and a fine filter module), which increases the dust holding capacity and ensures that the air filter element maintains low resistance during use, thus saving energy and reducing consumption.

[0088] In one embodiment, applying the above-mentioned air filter to a vehicle can improve the user's driving comfort. The air filter is washable and reusable, has a long lifespan (more than 3 times that of traditional filters), and can be replaced up to 100,000 km.

[0089] The following specific embodiments will further explain the air filter element prepared by the air filter element preparation method described above.

[0090] like Figure 3 and Figure 4 As shown, in one embodiment, the air filter element provided by the present invention includes a fine filter module 31 and a coarse filter module 32.

[0091] like Figure 3 As shown, in one embodiment, the fine filter module 31 and the coarse filter module 32 are bonded together by a hot melt adhesive strip 33.

[0092] like Figure 3 and Figure 4 As shown, in one embodiment, the fine filtration module 31 includes a fine filtration block 311 and a PET edge strip 312.

[0093] The fine filter block 311 is prepared by sequentially flattening, creasing, continuously applying glue to both sides, continuously folding and reciprocating, and slitting a multi-layer composite non-woven fabric roll 3111 (i.e., the filter medium of the air filter element).

[0094] like Figure 4 and Figure 5 As shown, in this embodiment, the continuous double-sided adhesive injection process evenly distributes the filter medium into multiple filter cavities 3112 of equal area. Each filter cavity 3112 is separated and fixed by a support rib 3113 formed by a hot melt adhesive line. At the same time, the continuous hot melt adhesive line forms a connecting rib 3114 on the surface after curing, which supports the filter medium and prevents the filter medium from collapsing.

[0095] like Figure 3 As shown, the PET strip 312 is bonded to the side of the fine filter block 311.

[0096] like Figure 3 and Figure 4 As shown, in one embodiment, the air filter element further includes a sealing ring 34.

[0097] Specifically, the sealing ring 34 is located at the edge of the fine filter module 31.

[0098] like Figures 3 to 6 As shown, in one embodiment, the side of the coarse filter module 32 away from the fine filter module 31 has a wavy shape.

[0099] like Figure 4 and Figure 7 As shown, the interior of the coarse filter module 32 has a three-dimensional mesh porous structure.

[0100] In summary, compared with the prior art, the air filter element prepared by this invention, and the air filter element itself, in the noise reduction process, firstly, uses a coarse filter module for sound absorption and noise reduction, filtering out large dust particles and preventing their accumulation on the surface of the fine filter module; simultaneously, the coarse filter module also reduces airflow velocity, thereby preventing the fine filter module from being damaged and extending the service life of the air filter element; then, the fine filter module performs precise filtration of minute pollutants, ensuring the noise reduction effect; the use of staged filtration increases dust holding capacity, ensuring continuous low resistance and energy saving during the use of the air filter element; therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0101] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for preparing an air filter element, characterized in that, Includes the following steps: Provides multi-layer composite nonwoven fabrics; The nonwoven fabric is processed to form a fine filter block; The sides of the fine filter block are sealed to form a fine filter module; Polyurethane foam is molded to form a coarse filter module; The fine filter module and the coarse filter module are connected to form an air filter element; The process of forming a fine filter block by processing the nonwoven fabric includes the following steps: The nonwoven fabric is indented. Hot melt adhesive lines are injected into both sides of the non-woven fabric after it has been embossed, so that the non-woven fabric after embossing is evenly distributed into multiple filter cavities with equal filtration areas to form filter paper blocks; adjacent filter cavities are divided and connected by support ribs formed by the hot melt adhesive lines. The filter paper block is folded continuously and without interruption to form the fine filter block; Before indenting the nonwoven fabric, the process of forming a fine filter block by processing the nonwoven fabric further includes: flattening the nonwoven fabric. The indentation process of the nonwoven fabric includes: indenting the nonwoven fabric after it has been leveled.

2. The method for preparing an air filter element according to claim 1, characterized in that, The process of forming a fine filter block includes: cutting the filter paper block that has been repeatedly folded to obtain the fine filter block.

3. The method for preparing an air filter element according to claim 1, characterized in that, The edge sealing treatment of the side of the fine filter block includes: bonding PET edge strips to the side of the fine filter block.

4. The method for preparing an air filter element according to claim 1, characterized in that, Prior to the step of connecting the fine filter module and the coarse filter module, the method for preparing the air filter element further includes: The fine filtration module is sealed. The connection between the fine filter module and the coarse filter module includes: connecting the sealed fine filter module and the coarse filter module.

5. The method for preparing an air filter element according to claim 1, characterized in that, The connection between the fine filter module and the coarse filter module includes: bonding the fine filter module and the coarse filter module with hot melt adhesive.

6. The method for preparing an air filter element according to claim 1, characterized in that, The side of the coarse filter module away from the fine filter module has a wavy, concave-convex shape.

7. An air filter element, characterized in that, The air filter element is prepared using the air filter element preparation method as described in any one of claims 1 to 6.

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