Air filter

Abstract

The utility model discloses an air filter which comprises an outer frame body and a filter main body arranged in the outer frame body, the filter main body comprises static electret non-woven fabric and a supporting material, the static electret non-woven fabric is of an n-shaped continuous bending structure, the supporting material is connected between two side folds of the static electret non-woven fabric, and the supporting material is of a space structure. The air filter disclosed by the utility model has the characteristics of low resistance and high trapping efficiency.

Description

Technical Field

[0001] This utility model relates to an air filter. Background Technology

[0002] Currently, air filters mainly include those with diaphragms and those without diaphragms. Diaphragm filters use ultra-fine glass fiber filter paper as the filter media, with folded materials such as PVC paper or aluminum foil as separators. Filterless filters mainly use PP electrostatic electret nonwoven fabric as the filter media, with hot melt adhesive as the separator in the filter element.

[0003] However, filters with pleats use fiberglass filter media, which has high air resistance and affects the purified air volume. Filters without pleats use electrostatic electret nonwoven fabric, with rubber strips between the pleats for support. Especially in cases of high pleat height or high air volume, the filter pleats are prone to deformation, and the pleats stick together, reducing the ventilation area, resulting in high air resistance and reduced filtration efficiency.

[0004] For example, Chinese utility model patent CN206492320U discloses a partitioned air filter, which includes an outer frame, partitions evenly spaced around the outer frame, and an internal filter media composed of three layers of glass fiber filter paper. This filter is a partitioned type, and although its air resistance is improved compared to a three-stage filter used in cleanrooms, the air resistance of the three-layer glass fiber filter media is still very high. When applied to general filtration applications, it results in low airflow and high energy consumption.

[0005] For example, Chinese utility model patent CN208771066U discloses an air filter for ultrafine particulate matter. This filter includes an outer frame and a filter element composed of multiple rows of parallel pleated fiber filter media in the shape of "M" or "W". This filter is a type without partitions. During ventilation, the deformation of the pleated fiber filter media causes high air resistance. Furthermore, due to the deformation of the filter media, the fibers stick together, resulting in a reduced effective utilization area and low cumulative purification capacity. Utility Model Content

[0006] The purpose of this invention is to provide an air filter with low resistance and high capture efficiency.

[0007] The technical solution of this utility model is as follows:

[0008] The air filter of this utility model includes an outer frame and a filter body disposed within the outer frame. The filter body includes a static electret nonwoven fabric with a Z-shaped continuous bending structure and a support material connected between the two sides of the static electret nonwoven fabric. The support material has a spatial structure.

[0009] The aforementioned spatial structure is preferably a folded or wavy corrugated structure.

[0010] Preferably, the bending direction of the above corrugated structure is vertically connected between the folds on both sides of the electrostatically charged electret non-woven fabric.

[0011] The folding height of the above electrostatically charged electret non-woven fabric is preferably 20 - 300 mm, and the folding distance is preferably 2 - 6 mm.

[0012] The height of the above corrugation is preferably 2.0 - 6.0 mm, and the distance between adjacent vertices of the corrugation is preferably 2.0 - 6.0 mm.

[0013] The above electrostatically charged electret non-woven fabric is preferably at least one of melt-blown non-woven fabric, needle-punched non-woven fabric or heat-bonded non-woven fabric.

[0014] The above support material is preferably an electrostatically charged electret non-woven fabric with a stiffness greater than 100 mg.

[0015] Advantages of the present utility model: The air filter of the present utility model features low resistance and high capture efficiency. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the three-dimensional structure of the air filter of the present utility model. Figure 2 It is a top view of the air filter of the present utility model. Figure 3 It is a schematic diagram of the structure of the filter main body. Among them: 1 is the outer frame body, 2 is the electrostatically charged electret non-woven fabric with a U-shaped continuous bending structure, and 3 is the support material.

[0017] Figure 4 It is a schematic diagram of the structure of the electrostatically charged electret non-woven fabric with a U-shaped continuous bending structure. Among them: A is the folding height, and B is the folding distance.

[0018] Figure 5 It is a schematic diagram of the structure of the folded support material. Among them: 3 is the support material, C is the height of the corrugation, and D is the distance between adjacent vertices of the corrugation. Detailed Embodiments

[0019] The air filter of the present utility model includes an outer frame body and a filter main body disposed within the outer frame body. The filter main body includes an electrostatically charged electret non-woven fabric with a U-shaped continuous bending structure and a support material connected between the folds on both sides of the electrostatically charged electret non-woven fabric. The support material has a spatial structure. The air filter of the present utility model belongs to a panel air filter. The outer frame body plays a role in airtightness. The electrostatically charged electret non-woven fabric with a U-shaped continuous bending structure can effectively reduce the air resistance of the filter screen and play a role in efficiently filtering particulate matter. The spatial structure support material is equivalent to a partition, mainly providing a channel for air flow and adsorbing and accommodating dust to a certain extent.

[0020] The aforementioned spatial structures, including supports, hollow tubes, corrugated or porous sponge structures, can all support the electrostatically electret nonwoven fabric in the Z-shaped continuous bending structure. When the support material is a support, hollow tube, or sponge structure, the connection between the electrostatically electret nonwoven fabric in the Z-shaped continuous bending structure and the support material is achieved through dot-matrix adhesive bonding; when the support material is a corrugated structure, the connection between the electrostatically electret nonwoven fabric in the Z-shaped continuous bending structure and the support material is achieved through adhesive bonding at the apex of one side of the corrugation. This ensures that the electrostatically electret nonwoven fabric and the support material do not shift in position and also improves production speed.

[0021] Considering the contact area and processability of the spatial structure support material and the electrostatic electret nonwoven fabric, the spatial structure is preferably a folded or wavy corrugated structure. When the apex of the corrugated structure is combined with the electrostatic electret nonwoven fabric, the volume occupied by the ventilation channel is maximized, which is conducive to airflow. Furthermore, the effective air contact area between the electrostatic electret nonwoven fabric and the spatial structure support material is maximized, and the utilization rate of the electrostatic electret nonwoven fabric is maximized.

[0022] Preferably, the bending direction of the above-mentioned corrugated structure is perpendicularly connected to the folds on both sides of the electrostatic electret nonwoven fabric. When the airflow passes through the corrugated channel, it can effectively reduce the air resistance of the corrugated structure itself, which is conducive to the uniform flow of air through the electrostatic electret nonwoven fabric, resulting in a filter with low air resistance.

[0023] The preferred fold height of the electrostatic electret nonwoven fabric is 20–300 mm, and the preferred fold spacing is 2.0–6.0 mm. If the fold height is too high, the electrostatic electret nonwoven fabric is prone to bending, making assembly with the support material difficult; if the fold height is too low, the usable area of ​​the electrostatic electret nonwoven fabric is small, leading to a tendency for increased filter resistance. Furthermore, if the fold spacing is too large, although the ventilation ducts become larger, the reduced usable area of ​​the electrostatic electret nonwoven fabric also tends to increase filter resistance; if the fold spacing is too small, the ventilation ducts of the corrugated spatial structure support material are small, and the support material is denser, resulting in poor ventilation and a tendency for increased filter resistance.

[0024] The corrugated height is matched with the fold spacing of the electrostatic electret nonwoven fabric with a continuous zigzag bending structure. Therefore, the preferred corrugated height is 2.0–6.0 mm, and the preferred spacing between adjacent vertices is 2.0–6.0 mm. If the corrugated height is too high or the spacing between adjacent vertices is too large, the supporting strength of the support material will be weakened, and the corrugated structure will be prone to bending under pressure. If the corrugated height is too low or the spacing between adjacent vertices is too small, the dense corrugated structure may lead to a reduction in ventilation channels and an increase in filter resistance.

[0025] The aforementioned electrostatic electret nonwoven fabric is preferably at least one of meltblown nonwoven fabric, needle-punched nonwoven fabric, or thermally bonded nonwoven fabric. The stiffness of the electrostatic electret nonwoven fabric is preferably greater than 50 mg. The electrostatic electret nonwoven fabric can be a single-layer structure or a two-layer structure. When the electrostatic electret nonwoven fabric is a single-layer structure, a layer of meltblown nonwoven fabric, needle-punched nonwoven fabric, or thermally bonded nonwoven fabric is folded into a continuous V-shaped bending structure, and then the bending direction of the corrugated support material is perpendicularly connected to the folds on both sides of the electrostatic electret nonwoven fabric, thereby assembling it into the filter body. When the electrostatic electret nonwoven fabric is a two-layer structure, it is preferable to bond the thermally bonded nonwoven fabric and meltblown nonwoven fabric together, then fold it into a continuous V-shaped bending structure, and then assemble it with the corrugated support material to form the filter body. The thermally bonded nonwoven fabric is an electrostatic electret thermally bonded nonwoven fabric formed of coarse fibers, mainly serving a shaping function, while the meltblown nonwoven fabric is an electrostatic electret meltblown nonwoven fabric formed of fine fibers, mainly serving a filtering function. During use, air flows in from the electrostatic electret thermal bonding nonwoven fabric and flows out from the electrostatic electret meltblown nonwoven fabric.

[0026] The aforementioned support material is preferably an electrostatic electret nonwoven fabric with a stiffness greater than 100mg. This not only provides support but also facilitates further increases in particulate matter filtration efficiency and dust holding capacity through electrostatic adsorption on the surface of the support material.

[0027] The present invention will be further illustrated by the following embodiments, but the scope of protection of the present invention is not limited to the embodiments. The physical property parameters in the embodiments are determined by the following methods.

[0028] [The fold height of electrostatic electret nonwoven fabric with a Z-shaped continuous bending structure]

[0029] First, separate the filter body from the frame, remove the filter body, remove the electrostatic electret nonwoven fabric with the Z-shaped continuous bending structure from the filter body, and then use a ruler to directly measure the Z-shaped fold height (B) at any 5 points, and calculate the average value of N=5.

[0030] The fold spacing of electrostatic electret nonwoven fabric with a continuous zigzag bending structure.

[0031] First, separate the filter body from the frame, remove the filter body, remove the electrostatic electret nonwoven fabric with the Z-shaped continuous bending structure from the filter body, and then use vernier calipers to directly measure the fold spacing (A) of any 5 Z-shaped points, and calculate the average value of N=5.

[0032] [Height of corrugated board]

[0033] First, separate the filter body from the frame. Take out the filter body and then use a vernier caliper to directly measure the corrugated height of the corrugated support material between the zigzag folds of the electrostatic electret nonwoven fabric, that is, the distance (D) between the peak and valley of the fold. Measure 5 sets of data and calculate the average value of N=5.

[0034] Spacing between adjacent vertices of a corrugated board

[0035] First, separate the filter body from the frame. Take out the filter body and then use a vernier caliper to directly measure the distance between two adjacent vertices of the corrugated support material with electrostatic electret nonwoven fabric folds, that is, the distance (C) between two adjacent fold peaks. Measure 5 sets of data and calculate the average value of N=5.

[0036] [Stiffness of the supporting material]

[0037] First, separate the filter body and the frame, remove the filter body, remove the support material from the filter body, and measure according to the JIS L1096 (Greyan type) standard. The test sample size is 38mm × 25mm. Calculate the average value of N = 5.

[0038] Pressure Loss

[0039] According to JIS B 9908-2001 standard, the air volume is 160m³. 3 At a pressure of / h, the pressure drop of the air filter is measured, and the result is read directly from the pressure gauge.

[0040] [Capture Efficiency]

[0041] According to JIS B 9908-2001 standard, the air volume is 160m³. 3 At a rate of / h, 0.3–0.5 μm electrostatically degraded KCl aerosol particles were used for testing. The formula for calculating the collection efficiency is as follows:

[0042]

[0043] Upstream particle count: The number of KCl aerosol particles in the metered gas flow above the filter cartridge.

[0044] Downstream particle count (number): The number of KCl aerosol particles in the metered gas below the filter cartridge.

[0045] Example 1

[0046] Preparation of electrostatic electret nonwoven fabric with a Z-shaped continuous bending structure: Electrostatic electret PET thermal bonding nonwoven fabric with a stiffness of 70mg and electrostatic electret PP meltblown nonwoven fabric with a filtration efficiency of 99.97% are laminated together. The two layers of electrostatic electret nonwoven fabric are folded into a Z-shaped continuous bending structure using a folding device, wherein the fold height is 20mm and the fold spacing is 2.0mm.

[0047] Preparation of support material: Using a corrugated folding device, electrostatic electret PET spunbond nonwoven fabric with a stiffness of 120mg is folded into a folded shape with a corrugation height of 2.0mm. The distance between adjacent vertices of the folded support material is 4.0mm.

[0048] Filter fabrication: A folded support material is glued to one side and then vertically bonded layer by layer to the folds of a continuously bent, zigzag-shaped electrostatic electret nonwoven fabric to obtain the filter body. Hot melt adhesive is then applied to the perimeter of the outer frame, and the filter body is placed inside the outer frame and bonded together, ultimately producing the air filter of this invention. The physical properties of this filter are shown in Table 1 below.

[0049] Examples 2-5

[0050] The preparation process is the same as in Example 1, and the specific formulation and properties are shown in Table 1.

[0051] Example 6

[0052] The preparation process of the electrostatic electret nonwoven fabric with a continuous bending structure in a zigzag shape is the same as in Example 4.

[0053] Preparation of support material: A material with a density of 25 kg / m³... 3 The porous sponge was cut into sheets with a thickness of 3mm.

[0054] Filter preparation: Apply adhesive to five points on one side of the porous sponge support material, including the four corners and the center, with an adhesive application area of ​​1-5 cm². 2 The filter body is made by vertically bonding layers of electrostatic electret nonwoven fabric with a continuously bent Z-shaped structure. Hot melt adhesive is then applied around the outer frame, and the filter body is placed inside the outer frame and bonded together, ultimately producing the air filter of this invention. The physical properties of this filter are shown in Table 1 below.

[0055] Comparative Example 1

[0056] A 120mg stiffness electrostatic electret PET thermally bonded nonwoven fabric and a 99.97% filtration efficiency electrostatic electret PP meltblown nonwoven fabric are laminated together. The two layers of electrostatic electret nonwoven fabric are then folded into a continuous Z-shaped bending structure using a folding device, with a fold height of 100mm and a fold spacing of 6.0mm. This is then assembled with an outer frame to obtain a filter without support material. The physical properties of this filter are shown in Table 1 below.

[0057] Comparative Example 2

[0058] Preparation of ordinary nonwoven fabric with a Z-shaped continuous bending structure: Ordinary PET nonwoven fabric with a stiffness of 120mg is folded into a Z-shaped continuous bending structure using a folding device, wherein the fold height is 100mm and the fold spacing is 3.0mm.

[0059] Preparation of support material: Using a corrugated folding device, PET spunbond nonwoven fabric with a stiffness of 120mg is folded into a folded shape with a corrugation height of 3.0mm. The distance between adjacent vertices of the folded support material is 6.0mm.

[0060] Filter fabrication: A folded corrugated support material is glued to one side and then vertically bonded layer by layer to the folds of a regular PET nonwoven fabric with a continuous zigzag bending structure to obtain the filter body. Hot melt adhesive is applied to the four sides of the outer frame, and the filter body is placed inside the outer frame and bonded together to obtain the final filter. The physical properties of this filter are shown in Table 1 below.

[0061] Comparative Example 3

[0062] Preparation of glass fiber nonwoven fabric with a continuous bending structure in the shape of a zigzag: The glass fiber filter is folded using a folding device, with a fold height of 100 mm and a fold spacing of 3.0 mm.

[0063] A folding device is used to fold 120mg PET spunbond nonwoven fabric into a continuous Z-shaped bending structure, with a fold height of 100mm and a fold spacing of 3.0mm.

[0064] Preparation of support material: Ordinary PET nonwoven fabric with a stiffness of 120mg is folded into a folded shape with a corrugation height of 3.0mm using a corrugated folding device. The distance between adjacent vertices of the folded support material is 6.0mm.

[0065] Filter fabrication: A folded corrugated support material is glued to one side and then vertically bonded layer by layer to the folds of a continuously bent, zigzag-shaped fiberglass nonwoven fabric to obtain the filter body. Hot melt adhesive is then applied to the perimeter of the outer frame, and the filter body is placed inside the outer frame and bonded together to obtain the final filter. The physical properties of this filter are shown in Table 1 below.

[0066] Table 1

[0067]

Claims

1. An air filter, characterized in that: The air filter includes an outer frame (1) and a filter body disposed within the outer frame (1). The filter body includes a static electret nonwoven fabric (2) with a Z-shaped continuous bending structure and a support material (3) connected between the folds on both sides of the static electret nonwoven fabric (2). The support material (3) has a spatial structure.

2. The air filter according to claim 1, characterized in that: The spatial structure is a folded or wavy corrugated structure.

3. The air filter according to claim 2, characterized in that: The bending direction of the corrugated structure is perpendicularly connected to the folds on both sides of the electrostatic electret nonwoven fabric (2).

4. The air filter according to claim 1, characterized in that: The fold height (A) of the electrostatic electret nonwoven fabric (2) is 20-300 mm, and the fold spacing (B) is 2.0-6.0 mm.

5. The air filter according to claim 2, characterized in that: The height (C) of the corrugation is 2.0 to 6.0 mm, and the distance (D) between adjacent vertices of the corrugation is 2.0 to 6.0 mm.

6. The air filter according to claim 1, characterized in that: The electrostatic electret nonwoven fabric (2) is at least one of meltblown nonwoven fabric, needle-punched nonwoven fabric or thermally bonded nonwoven fabric.

7. The air filter according to claim 1, characterized in that: The support material (3) is an electrostatic electret nonwoven fabric with a stiffness greater than 100mg.

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