Filter and method of manufacturing the same

Abstract

The present disclosure relates to a filter and a manufacturing method thereof. The filter includes a dust collecting unit, and the dust collecting unit includes a filter medium formed in a pleated shape including a plurality of curved portions folded up and down in a direction parallel to a plurality of parallel patterns and a connection portion, a conductive coating pattern including a plurality of parallel patterns, and a first power source electrically connected to first and second ends of the conductive coating pattern and configured to apply a voltage, wherein the connection portion connects adjacent curved portions, one parallel pattern of the plurality of parallel patterns is disposed in the connection portion, and the plurality of parallel patterns include a first adjacent parallel pattern and a second adjacent parallel pattern, and a first current flowing through the first adjacent parallel pattern flows in a direction opposite to a second current flowing through the second adjacent parallel pattern.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0188378, filed on December 30, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to filters and methods of manufacturing the same. Background Technology

[0004] The statements in this section are provided only as background information in connection with this disclosure and may not constitute prior art.

[0005] Non-woven fabric filters or electrostatic precipitators are typically used in air conditioning systems.

[0006] In the case of conventional nonwoven filters, due to physical collection, a dense structure of the nonwoven filter is desirable to improve dust collection efficiency, but this also causes significant pressure loss during air conditioning system operation. Furthermore, as the dust collection rate increases, the spaces between the nonwoven fibers become narrower, leading to increased pressure loss.

[0007] To mitigate this pressure loss, a common approach is to increase the filter's surface area within a limited space by adding more bends and ridges. However, when the air conditioning system is running, adjacent bends and ridges can stick together, reducing dust collection efficiency and increasing pressure loss.

[0008] To suppress this adhesion between the curved sections, the filter fabric is fixed by heat fusion, which is a method to fix the filter fabric and suppress the adhesion between the curved sections. However, this requires an additional process, and the fixing force of the filter fabric is further deteriorated by heat fusion.

[0009] In the case of conventional electrostatic precipitators, dust is collected in the dust collection unit by electricity through charging dust particles and forming an electric field, and such conventional electrostatic precipitators are still expected to have improved dust collection efficiency.

[0010] The information disclosed in this background section is only intended to enhance the understanding of the background technology of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0011] This disclosure provides filters and manufacturing methods that can improve conventional dust collection filters, suppress pressure drops and adhesion between curved sections, and provide increased dust collection efficiency.

[0012] The filter according to an exemplary form of this disclosure relates to a filter including a dust collection unit.

[0013] The dust collection unit may include a filter medium, a conductive coating pattern, and a first power source electrically connected to a first end and a second end of the conductive coating pattern and configured to apply a voltage.

[0014] The conductive coating pattern may include multiple parallel patterns, and the filter medium may be formed into a wrinkled shape, which includes multiple curved portions folded up and down along a direction parallel to the multiple parallel patterns and connecting portions connecting adjacent curved portions.

[0015] Parallel patterns can be set in the connecting part, and currents in opposite directions can flow between adjacent parallel patterns.

[0016] The conductive coating pattern can be a zigzag pattern, wherein multiple parallel patterns are connected at offset positions in the upper and lower parts of the conductive coating pattern.

[0017] When a voltage is applied to the conductive coating pattern, a repulsive force can act between parallel patterns in adjacent connected portions.

[0018] The filter medium can have a structure with multiple fine fibers randomly intersecting.

[0019] Conductive coating patterns allow conductive particles to adhere to the surface of fine fibers.

[0020] Conductive particles can be conductive nanoparticles.

[0021] The conductive particles can be conductive nanowire particles.

[0022] The thickness of the conductive nanowire particles can be 100 nm to 200 nm and the length can be 150 μm or less.

[0023] It may further include a charging unit disposed in front of the dust collection unit and charging the dust particles.

[0024] Dust particles charged in the charging unit can be collected in the conductive coating pattern using electricity and van der Waals forces.

[0025] It may further include a second power source electrically connected to the charging unit and configured to apply a high voltage.

[0026] It may further include a second power source electrically connected to the charging unit and the dust collection unit and configured to apply a high voltage.

[0027] The electric field can be generated by the voltage difference between the charging unit and the dust collection unit.

[0028] Filters can be used in air conditioning units or air conditioning systems.

[0029] A filter manufacturing method according to an exemplary form of the present disclosure includes: folding a filter medium alternately up and down to form a pleated shape, the pleated shape including a plurality of curved portions and connecting portions connecting adjacent curved portions; forming a conductive coating pattern on the filter medium; and electrically connecting a first end and a second end of the conductive coating pattern to a first power source.

[0030] When forming a conductive coating pattern on a filter medium, the conductive coating pattern may include multiple parallel patterns, and one of the multiple parallel patterns may be formed and positioned on the connecting portion.

[0031] The conductive coating pattern can be a zigzag pattern, wherein multiple parallel patterns are mismatched and connected to each other in the upper and lower parts of the conductive coating pattern.

[0032] The filter media can have a structure with multiple intersecting fine fibers.

[0033] Conductive particles can adhere to a surface formed by multiple fine fibers and form a conductive coating pattern.

[0034] Before forming a conductive coating pattern on the filter medium, the process may further include preparing a conductive nanowire solution and cleaning the surface of the conductive nanowires.

[0035] A conductive coating pattern can be formed by spraying it onto the filter medium.

[0036] The formation of conductive coating patterns on the filter media can be performed two or more times.

[0037] The filter media can have a structure with multiple fine fibers randomly intersecting, and the conductive coating pattern can allow conductive particles to adhere to the surface of the fine fibers.

[0038] The conductive particles can be conductive nanowire particles.

[0039] The thickness of conductive nanowire particles can range from 100 nm to 200 nm.

[0040] The length of the conductive nanowire particles can be 150 μm or smaller.

[0041] In addition to improving dust collection efficiency, filters and their manufacturing methods can also be provided to reduce pressure loss and adhesion between curved sections.

[0042] Further areas of application will become apparent from the description provided herein. It should be understood that the descriptions and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0043] To better understand this disclosure, various forms of the disclosure, given by way of example, will now be described with reference to the accompanying drawings, in which:

[0044] Figure 1 This is a schematic diagram illustrating the structure of a filter according to an exemplary form of this disclosure;

[0045] Figure 2 It is a diagram showing the conductive coating pattern formed on the filter medium and the flow of current when a voltage is applied to the conductive coating pattern;

[0046] Figure 3A , Figure 3B and Figure 3C It is a diagram used to explain the principle of the force acting between conductive coating patterns in adjacent connected portions;

[0047] Figure 4 This is a photograph of the dust collection unit of one type of filter disclosed herein;

[0048] Figure 5 These are SEM images of a dust collection unit of a filter according to an exemplary form of this disclosure;

[0049] Figure 6 This is a diagram illustrating an air conditioning system with a filter applied according to another form of this disclosure;

[0050] Figure 7 This is a photograph of a filter including a charging unit and a dust collection unit, according to an exemplary form of this disclosure;

[0051] Figure 8 This is a diagram illustrating the dust collection principle of a filter according to another form of this disclosure;

[0052] Figure 9 This is a diagram illustrating the dust collection principle of a filter according to another form of this disclosure;

[0053] Figure 10 This is a diagram illustrating a filter manufacturing process according to an exemplary form of this disclosure;

[0054] Figure 11A , Figure 11B and Figure 11C This is a diagram illustrating a detailed process of coating steps in one form of this disclosure;

[0055] Figure 12 It is a graph showing the measured resistance of the thin film based on the number of coatings per nanowire length under the same weight coating conditions; and

[0056] Figure 13 It is a graph that estimates the dust collection performance of the exemplary form and the comparative example.

[0057] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way. Detailed Implementation

[0058] The following description is exemplary in nature only and is not intended to limit this disclosure, its application, or its uses. It should be understood that in all the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0059] Furthermore, unless explicitly stated otherwise, the words “comprise” and variations such as “comprises” or “comprising” will be understood to imply inclusion of the stated element, but not to exclude any other element.

[0060] Unless otherwise indicated, a singular term may include a plural term.

[0061] It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element or there may be intermediate elements present. Conversely, when an element is referred to as being "directly on" another element, there are no intermediate elements present.

[0062] Furthermore, throughout the instruction manual, "on" means positioned above or below the target component, and does not mean that it must be positioned at the top based on the direction of gravity.

[0063] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part.

[0064] Although not specifically defined, all terms, including the technical and scientific terms used herein, shall have the meaning as understood by one of ordinary skill in the art.

[0065] The filter disclosed herein can improve dust collection efficiency, while simultaneously mitigating the problem of pressure loss degradation and suppressing adhesion between curved sections.

[0066] The filter according to this disclosure and its manufacturing method are described in detail below.

[0067] <Filter>

[0068] A filter according to an exemplary form of this disclosure includes a filter medium, a conductive coating pattern, and a dust collection unit, the dust collection unit including a first power source electrically connected to the conductive coating pattern to apply a voltage.

[0069] The conductive coating pattern can include multiple parallel patterns.

[0070] The filter medium can have a pleated shape, which consists of curved portions folded up and down along a direction parallel to multiple parallel patterns and connecting portions connecting adjacent curved portions. The curved portions can be "Λ"-shaped or "Π"-shaped, but are not limited to these.

[0071] Parallel patterns can be positioned on the connecting parts.

[0072] Current flowing in opposite directions can flow through adjacent parallel patterns. In this case, the current flowing in opposite directions generates a repulsive force between adjacent parallel patterns, eliminating the need for separate structures such as heat-sealing, and suppressing adhesion between adjacent bends or adjacent connections, thereby maintaining the wrinkled shape and improving the pressure loss of the filter.

[0073] Figure 1 This is a schematic diagram illustrating the structure of a filter according to an exemplary form of this disclosure.

[0074] like Figure 1 As shown, parallel patterns can be positioned at the same height relative to the baseline.

[0075] The conductive coating pattern can be a zigzag pattern, in which multiple parallel patterns are connected at offset positions at the top and bottom. In this case, there is an advantage that the current between adjacent parallel patterns can be designed to flow in opposite directions through a simple electrical connection.

[0076] Figure 2 This is a diagram illustrating a conductive coating pattern formed in a filter medium and the flow of current when a voltage is applied to the conductive coating pattern. The conductive coating pattern includes a plurality of parallel patterns 13 and connecting patterns 14, which connect adjacent parallel patterns at mismatched positions at the upper and lower parts.

[0077] like Figure 2 As shown, the current flows in one direction in a sawtooth pattern along the conductive coating pattern, and the current flows in opposite directions in the conductive coating patterns formed in adjacent connecting portions.

[0078] Figure 3A , Figure 3B and Figure 3C It is a diagram used to explain the principle of the force acting between conductive coating patterns in adjacent connected parts. Figure 3AThe magnetic field generated in the first region and the force exerted by the first region on the second region are shown. Figure 3B It is the magnetic field generated in the second region and the force exerted on the first region by the second region, and Figure 3C The force acting between parallel patterns in adjacent connecting portions is shown.

[0079] When current flows in opposite directions through parallel patterns located in adjacent connecting portions, a repulsive force acts between the parallel patterns of the two adjacent connecting portions. Therefore, adhesion between adjacent curved sections of the filter media can be suppressed. That is, a form of filter disclosed herein maintains the gap between curved sections without the need for separate structures such as heat-sealed fasteners, and can improve the pressure loss performance of the filter.

[0080] The conductive coating pattern can be applied to the entire thickness direction of the filter medium, to one surface of the filter medium, or to a local area of ​​the thickness direction of one surface of the filter medium. Even in this case, adhesion between the curved portions of the filter medium can be suppressed.

[0081] The conductive coating pattern can be positioned on a surface of the filter medium, or it can be positioned on a localized area in the thickness direction of a surface of the filter medium. When the conductive coating pattern is positioned on a localized area in the thickness direction of a surface of the filter medium, the conductive coating pattern can be positioned in front of the filter medium.

[0082] In this specification, when the surface in which air enters is referred to as the first surface and the surface out which air exits is referred to as the second surface, the front of the filter medium refers to the direction in which air enters from the first surface.

[0083] Filter media can be formed by interlacing multiple fine fibers. Air can move through the spaces between the fine fibers.

[0084] If the space between the fibers is too narrow, the resistance to airflow increases, and then the pressure loss may increase.

[0085] Considering the application and air resistance, the spacing between multiple microfibers and the thickness of the microfibers can be adjusted appropriately as needed.

[0086] The filter media can be made of non-woven fabric.

[0087] The filter media can be polyester, polypropylene, and / or glass fiber.

[0088] Activated carbon can be added to the filter media, which can improve odor collection efficiency.

[0089] If necessary, filter media with manually applied electrostatic force can be used, and in this case, the initial performance of the filter can be improved.

[0090] However, it is not limited to this, and it can be applied in various ways as long as it can collect dust particles of micro-unit size.

[0091] Conductive coating patterns can be formed by attaching conductive particles to the surface of the fine fibers constituting the filter media. In this case, since the coating can be formed without sealing the spaces between multiple fine fibers, the reduction in pressure loss can be minimized.

[0092] The conductive particles can be conductive nanoparticles. In this case, the gaps between multiple fine fibers are not closed, and the conductive coating pattern can be obtained with almost no impact on the gaps between the fine fibers. In other words, the conductive coating pattern has almost no impact on the coarseness of the filter media, thus reducing pressure loss.

[0093] Conductive nanoparticles can be used without restriction, as long as the conductive nanoparticles are nanoscale conductive materials.

[0094] The conductive particles can be conductive nanowire particles. In this case, due to the high aspect ratio of the nanowires, a network structure is formed, which promotes electrical connections and improves conductivity.

[0095] The conductive nanoparticles can be silver nanowires, carbon nanowires, gold nanowires, and / or platinum nanowires. In this case, there are advantages such as high conductivity, antibacterial properties, and corrosion resistance.

[0096] A photograph of a dust collection unit as an exemplary form of a filter according to this disclosure. Figure 4 It is a photograph of a filter medium with a conductive coating pattern.

[0097] Figure 5 This is a SEM photograph of the dust collection unit of a filter according to another form of this disclosure.

[0098] This demonstrates the formation of a silver nanowire coating on a nonwoven filter medium composed of polypropylene and polyester. The filter medium has a nonwoven structure in which microfibers are randomly interwoven, and silver nanowires are attached to the surface of the microfibers to form a conductive coating. The silver nanowires are approximately 100 nm thick and approximately 70 μm long.

[0099] The thickness of the conductive nanowire particles can range from 100 nm to 200 nm. Specifically, the thickness can range from 120 nm to 150 nm.

[0100] If the nanowire particles are too thick, the conductive coating may become too thick, and the gaps between the microfibers in the filter media may become too narrow, potentially increasing pressure loss when the air conditioning system is running. If the nanowire particles are too thin, they may be easily damaged due to their low mechanical strength and chemical stability.

[0101] The length of the conductive nanowire particles can be 150 μm or less. Specifically, the length can be 140 μm or less, 120 μm or less, 20 μm to 150 μm, 20 μm to 140 μm, 40 μm to 140 μm, 80 μm to 140 μm, 100 μm to 140 μm, 120 μm to 140 μm, 40 μm to 120 μm, 40 μm to 100 μm, or 70 μm to 90 μm.

[0102] If the nanowire particles are too long, impurities generated due to twisting between the nanowires may lead to difficulties in the coating process and a deterioration in quality.

[0103] If the nanowire particles are too short, the contact points between the wires increase due to the low aspect ratio, and therefore the conductivity decreases due to the increased contact resistance.

[0104] Figure 12 This is a graph showing the measured resistance of the thin film based on the number of coatings per nanowire length under the same weight coating conditions.

[0105] refer to Figure 12 It can be seen that when the length of the nanowire meets this range, the resistance of the thin film decreases.

[0106] The width of the filter media connection (i.e., the spacing between adjacent bends) can be appropriately adjusted according to the size of the filter product and the pressure loss.

[0107] Considering the width of the filter media connection and the serrated conductive coating pattern, the width of the conductive coating pattern and the coating spacing L can be adjusted appropriately as needed.

[0108] Figure 6 This is a schematic diagram illustrating an air conditioning system that utilizes a filter of one type according to this disclosure. (Reference) Figure 6 The diagram shows a structure in which the outdoor air inlet section 4 and the indoor air inlet section 5 are positioned in front of the charging unit 2 and the dust collection unit 1, and the blower motor 6 is positioned at the rear.

[0109] A filter according to another form of the present disclosure may include a charging unit positioned in front of the dust collection unit and charging dust particles flowing in from the outside.

[0110] In this specification, when the surface into which air enters is referred to as the first surface and the surface out of which air is referred to as the second surface, the front of the dust collection unit refers to the surface located on the first surface of the dust collection unit, and is used to mean that it is spaced apart and located on the first surface of the dust collection unit.

[0111] Figure 7 This is a photograph of a filter according to another form of the present disclosure. It can be seen that the filter according to another form of the present disclosure includes a charging unit spaced apart from and positioned in front of the current collector.

[0112] Figure 8 This is a diagram illustrating the dust collection principle of a filter according to another form of this disclosure.

[0113] The second power source is the one that applies a high voltage.

[0114] The second power source is electrically connected to the charging unit and applies a high voltage to the charging unit through the second power source. Specifically, both the positive and negative terminals of the second power source can be connected to the charging unit.

[0115] The charging unit, which is subjected to a high voltage, charges the incoming dust, and the charged dust particles are moved by the airflow and then adhered to the conductive coating pattern by the electric field and van der Waals forces around the dust collection unit.

[0116] Figure 9 This is a diagram illustrating the dust collection principle of a filter according to another form of this disclosure.

[0117] The second power supply is electrically connected to the charging unit and the dust collection unit, and the electric field is generated by the voltage difference between the charging unit and the dust collection unit.

[0118] The incoming dust particles are charged in the charging unit, move through the electric field formed between the charging unit and the dust collection unit, and adhere to the conductive coating pattern of the dust collection unit using electricity and van der Waals forces.

[0119] Specifically, the charging unit is connected to the negative terminal of the second power supply, and the dust collection unit is connected to the positive terminal of the second power supply. In this case, the efficiency can be relatively improved. However, it is not limited to this, and the charging unit can also be connected to the positive terminal of the second power supply and the dust collection unit to the negative terminal.

[0120] To explain the electrical connection between the second power source and the dust collection unit, the electrical connection between the positive terminal of the first power source and one end A of the conductive pattern is called the first line, and the electrical connection between the negative terminal of the first power source and the other end B of the conductive pattern is called the second line.

[0121] The dust collection unit can be electrically connected to a second power source via either the first or second line. Figure 9This illustrates the case where the dust collection unit is electrically connected to a second power source on a second line.

[0122] When the positive voltage of the first power supply is denoted as αV and the positive voltage of the second power supply is denoted as βV, the relationship between α and β is βV ≥ 1000 * αV, and dust is generated between the charging unit and the dust collection unit. Large voltage difference.

[0123] The positive voltage βV of the second power supply can be from +1kV to +3kV. This positive voltage βV can also be from +1kV to +2kV.

[0124] If the positive voltage αV of the first power supply is less than 220V, it is sufficient. Specifically, the positive voltage αV can be 50V to 220V, 80V to 220V, 100V to 200V, 130V to 200V, or 150V to 220V.

[0125] Conventional electrostatic precipitators collect dust using electricity, but in the case of the filter according to this disclosure, dust collection efficiency is improved due to the use of van der Waals forces as well as physical and electrical dust collection, and there is an advantage that dust will not be reabsorbed by van der Waals forces even when the power is turned off.

[0126] The van der Waals force is due to the attraction between the filter media and the conductive coating and the dust particles. Van der Waals forces are essentially forces acting between molecules, and when dust particles are small, the van der Waals forces are very strong due to their large surface area, causing the dust particles to adhere stably.

[0127] Furthermore, since the filter disclosed herein collects dust via electricity and van der Waals forces, dust collection efficiency can be improved even when using filter media with a lower density than conventional nonwoven filters, and there is an advantage that there is almost no pressure loss depending on the density of the filter media.

[0128] The charging unit may include at least one charging pin, and dust can be charged by applying a high voltage to the charging pin. The number and arrangement of the charging pins can be adjusted according to the area of ​​the dust collection filter, and the voltage applied to the charging pins can be adjusted according to the flow rate and the distance to the filter.

[0129] However, this disclosure is not limited thereto, and unless there are special circumstances, the structure of the charging unit used in the art can be applied.

[0130] The filter can have a collection rate of 40% or higher for particles larger than 0.3 μm and smaller than 1 μm. Specifically, this collection rate can be 40% to 99%, 45% to 99%, 50% to 99%, 54% to 99%, 40% to 95%, 45% to 95%, 50% to 95%, 54% to 95%, 40% to 90%, 45% to 90%, 50% to 90%, or 54% to 90%.

[0131] The filter can have a collection rate of 40% or higher for particles larger than 0.3 μm and smaller than 0.5 μm. Specifically, this collection rate can be 40% to 99%, 45% to 99%, 50% to 99%, 54% to 99%, 40% to 95%, 45% to 95%, 50% to 95%, 54% to 95%, 40% to 90%, 45% to 90%, 50% to 90%, 54% to 90%, 40% to 70%, 45% to 70%, 50% to 70%, 54% to 70%, 40% to 65%, 45% to 65%, 50% to 65%, or 54% to 65%.

[0132] The filter can have a collection rate of 40% or higher for particles larger than 0.5 μm and smaller than 1 μm. Specifically, this collection rate can be 40% to 99%, 45% to 99%, 50% to 99%, 54% to 99%, 40% to 95%, 45% to 95%, 50% to 95%, 54% to 95%, 40% to 90%, 45% to 90%, 50% to 90%, 54% to 90%, 60% to 99%, 60% to 95%, or 60% to 90%.

[0133] The filter can have a collection rate of 80% to 99.9% for particles larger than 5 μm and smaller than 10 μm. Specifically, the collection rate can be 85% to 99.9%, 90% to 99.9%, 85% to 99%, or 90% to 99%.

[0134] The filter can achieve a collection rate of 80% to 99.9% for particles larger than 3 μm and smaller than 5 μm. Specifically, the collection rate can be 85% to 99.9%, 90% to 99.9%, 85% to 99%, or 90% to 99%.

[0135] The filter can achieve a collection rate of 80% to 99.9% for particles larger than 5 μm and smaller than 10 μm. Specifically, this collection rate can be 85% to 99.9%, 90% to 99.9%, 93% to 99.9%, 95% to 99.9%, 97% to 99.9%, 85% to 99%, 90% to 99%, 93% to 99%, 95% to 99%, or 97% to 99%.

[0136] Filters can be used in air purification devices, air filters, air conditioning units, or air conditioning systems.

[0137] Next, the filter manufacturing method will be described. Descriptions overlapping with those described in the filter section above will be omitted.

[0138] <Filter Manufacturing Method>

[0139] Figure 10 This is a diagram illustrating a filter manufacturing process according to an exemplary form of this disclosure.

[0140] One form of filter manufacturing method disclosed herein includes a folding step of alternately folding a filter medium to form a pleated shape, and a coating step of forming a conductive coating pattern on the filter medium.

[0141] When a coating is formed after the folding step of the filter media, there is an advantage in reducing damage to the coating on the bent portions caused by the folding of the filter media.

[0142] In the folding step, the filter medium can be folded into a pleated shape consisting of curved portions and connecting portions that connect adjacent curved portions. As mentioned above, the curved portions can be in the form of "Λ" or "Π".

[0143] In the coating step, the conductive coating pattern may include multiple parallel patterns.

[0144] Parallel patterns can be formed and positioned on the connecting parts.

[0145] In the coating step, the conductive coating pattern can be a zigzag pattern, wherein multiple parallel patterns are mismatched and connected to each other in the upper and lower parts.

[0146] Following the coating step, an electrical connection step may be further included, in which a first power source is electrically connected to both ends of the conductive coating pattern.

[0147] In this case, as described above, when a voltage is applied to the conductive coating pattern, a repulsive force appears between the parallel patterns of adjacent connecting portions, thereby suppressing adhesion between the curved mountain-shaped portions.

[0148] The coating process can involve forming a conductive coating pattern by methods such as spraying or dipping. However, it is not limited to this, and other coating methods can be applied as long as a pattern that can form a conductive coating pattern is available.

[0149] Specifically, the coating step can be performed by spraying. In this case, by minimizing coating unevenness and minimizing resistance, there are advantages such as improved quality uniformity, maximized electrostatic force, and improved dust collection efficiency. Furthermore, conductive coating patterns can be formed on the filter media with minimal impact on the density of the filter media.

[0150] The coating process can be performed in more than one coat. Specifically, two or more coats, two to five coats, or two to four coats can be performed. In this case, a conductive coating pattern with very low sheet resistance can be formed. If the number of coats is too small, the sheet resistance of the resulting conductive coating pattern may be very high.

[0151] If too much coating is applied, the effect of reducing the film resistance will be minimal, production costs will increase, and process efficiency may decrease.

[0152] Figure 11A , Figure 11B and Figure 11C This is a diagram illustrating a detailed process of one form of coating steps in this disclosure.

[0153] This can be further included as a step of preparing a conductive nanowire solution prior to the coating step.

[0154] The steps for preparing nanowire solutions can be the same as those for preparing silver nanowire solutions.

[0155] In an exemplary form of this disclosure, the steps for preparing a silver nanowire solution are performed using a polyol method, wherein the silver salt is reduced by ethylene glycol in the presence of polyvinylpyrrolidone (hereinafter “PVP”). Specifically, the solution is prepared by dissolving 0.8 g of PVP (molecular weight 360,000) and 1 g of silver nitrate (AgNO3) in 100 mL of ethylene glycol. Then, 3.6 mL of ethylene glycol solution in which ferric chloride (FeCl3) is dissolved at a concentration of 2 mM is uniformly mixed into the above solution. Finally, the solution is heated in an oil bath at 130 °C for 4 hours. During this process, the adhesion and growth of Ag on the {100} surface are inhibited due to the selective attachment of Cl or PVP to the {100} surface of the silver nanoparticles, and nanowires are synthesized by growth along the length direction.

[0156] The prepared conductive nanowire solution can be diluted with ethanol and centrifuged to perform three or more steps to clean the conductive nanowires.

[0157] The following embodiments illustrate the present disclosure in more detail. However, the following forms are merely exemplary forms of the present disclosure, and the present disclosure is not limited to these forms.

[0158] The filter medium is folded alternately up and down to form a wrinkled shape consisting of curved portions and connecting portions that connect adjacent curved portions, and a conductive coating is formed on the filter medium by spraying.

[0159] The conductive coating forms a zigzag pattern, wherein multiple parallel patterns are connected at mismatched positions at the upper and lower parts, and the conductive coating pattern is formed such that the parallel patterns are positioned on the connecting portion of the pleated filter medium.

[0160] The conductive coating is electrically connected to a first power source at both ends. The charging unit is positioned in front of the dust collection unit, spaced apart from it, and connected to a second power source. This allows the charging unit to apply a high negative voltage, while a high positive voltage is connected to the dust collection unit. Figure 9 That configuration.

[0161] The filter media used is composed of polypropylene and polyester. For example... Figure 5 As shown, the conductive coating is in the form of silver nanowires attached to the surface of the fine fibers constituting the filter medium. The thickness of the silver nanowires is about 100 nm and the length of the silver nanowires is about 80 μm.

[0162] The second power supply applies high voltages of -2kV and 2kV to the charging unit and the dust collection unit respectively, and the first power supply is connected to both ends of the conductive coating pattern of the dust collection unit to apply a voltage of about 200V and evaluate the dust collection performance.

[0163] <Comparative Example>

[0164] The comparative example uses a dust collection unit without a conductive coating, and the dust collection performance is evaluated under the same conditions as that of the form, except that the charging unit is not included.

[0165] <Evaluation Example - Filter Dust Collection Performance Evaluation Experiment>

[0166] Dust collection performance evaluation experiments were performed on filters of an exemplary form according to this disclosure.

[0167] Figure 13 It is a graph showing the collection rate depending on the particle size of the filter, based on the exemplary form and comparative examples.

[0168] like Figure 13 As shown, in this form, compared with the comparative example, the collection performance is improved for particles smaller than 1 μm and particles larger than 3 μm, and overall it can be seen that it exhibits excellent collection efficiency for ultrafine dust with very small size that is difficult to collect.

[0169] Specifically, it was confirmed that the collection rate of particles smaller than 1 μm was significantly increased to greater than 54% in this form, compared to 38% in the comparative example. Furthermore, it can be seen that the collection rate of particles larger than 3 μm also increased from 94% to 99%.

[0170] This disclosure may be formed in many different forms and should not be construed as being limited to the disclosed form. Furthermore, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the technical spirit and essential characteristics of this disclosure. Therefore, it should be understood that the foregoing forms are for illustrative purposes only, and the scope of this disclosure is not limited thereto.

[0171] <Symbol Explanation>

[0172] 1. Dust collection unit; 2. Charging unit; 4. Outdoor air inlet section.

[0173] 5. Indoor air inlet section, 6. Blower motor, 11. Filter media.

[0174] 12. Conductive coating pattern; 13. Parallel pattern.

[0175] 14 Connecting pattern, 15 Curved part, 16 Connecting part

[0176] 17 First power supply, 18 Second power supply.

Claims

1. A filter comprising a dust collecting unit, the dust collecting unit comprises: a filter medium formed in a pleated shape, the pleated shape comprising a plurality of curved portions folded up and down along a direction parallel to a plurality of parallel patterns, and a connection portion connecting adjacent curved portions among the plurality of curved portions; a conductive coating pattern comprising the plurality of parallel patterns; and a first power source electrically connected to first and second ends of the conductive coating pattern and configured to apply a voltage, wherein: the connection portion connects adjacent curved portions among the plurality of curved portions, a parallel pattern among the plurality of parallel patterns is disposed in the connection portion, and the plurality of parallel patterns comprise a first adjacent parallel pattern and a second adjacent parallel pattern, and a first electric current flowing through the first adjacent parallel pattern flows in a direction opposite to a second electric current flowing through the second adjacent parallel pattern. the conductive coating pattern is formed in a zigzag shape, and the plurality of parallel patterns are connected at positions offset from each other in upper and lower portions of the conductive coating pattern.

2. The filter of claim 1, wherein, repulsive forces act between the plurality of parallel patterns when a voltage is applied to the conductive coating pattern.

3. The filter of claim 1, wherein, the filter medium comprises a plurality of fine fibers that are randomly crossed, and 4. The filter of claim 1, wherein, the plurality of fine fibers form a surface to which conductive particles are attached, the conductive particles forming the conductive coating pattern. the conductive particles are conductive nanoparticles.

5. The filter of claim 4, wherein, the conductive nanoparticles are conductive nanowire particles.

6. The filter of claim 5, wherein, the conductive nanowire particles have a thickness of 100 nm to 200 nm and a length of 150 μm or less.

7. The filter of claim 6, wherein, 8.The filter of claim 1, further comprising a charging unit disposed in front of the dust collecting unit and configured to charge dust particles. the dust particles charged in the charging unit are collected in the conductive coating pattern by electric and van der Waals forces.

9. The filter of claim 8, wherein, 10.The filter of claim 9, further comprising a second power source electrically connected to the charging unit and configured to apply a high voltage. 11.The filter of claim 9, further comprising a second power source electrically connected to the charging unit and the dust collecting unit and configured to apply a high voltage, an electric field is generated by a voltage difference of the charging unit and the dust collecting unit. wherein, the filter is configured to be applied to an air conditioning device or an air conditioning system.

12. The filter of claim 1, wherein, 13.A filter manufacturing method comprising the steps of: folding up and down a filter medium and forming a pleated shape composed of a plurality of curved portions and a connection portion connecting adjacent curved portions among the plurality of curved portions; forming a conductive coating pattern on the filter medium; and electrically connecting first and second ends of the conductive coating pattern to a first power source, and wherein the conductive coating pattern comprises a plurality of parallel patterns, and the plurality of parallel patterns are formed to be positioned on the connection portion, and wherein the plurality of parallel patterns comprise a first adjacent parallel pattern and a second adjacent parallel pattern, and a first electric current flowing through the first adjacent parallel pattern flows in a direction opposite to a second electric current flowing through the second adjacent parallel pattern. ​ ​ 14.The filter manufacturing method of claim 13, wherein, the conductive coating pattern is formed in a zigzag shape, and the plurality of parallel patterns are connected to each other out of phase in an upper portion and a lower portion of the conductive coating pattern. 15.The filter manufacturing method of claim 13, wherein, the filter medium includes a plurality of fine fibers that are crossed, and the plurality of fine fibers form a surface to which conductive particles are attached, the conductive particles forming the conductive coating pattern. 16.The filter manufacturing method of claim 13, further comprising the steps of: manufacturing a conductive nanowire solution before forming the conductive coating pattern on the filter medium; and cleaning a surface of the conductive nanowire.

17. The filter production method according to claim 13, wherein, forming the conductive coating pattern on the filter medium by spraying.

18. The filter production method according to claim 17, wherein, forming the conductive coating pattern on the filter medium is performed two or more times. 19.The filter manufacturing method of claim 13, wherein, the filter medium includes a plurality of fine fibers that are randomly crossed, and the plurality of fine fibers form a surface to which conductive particles are attached. 20.The filter manufacturing method of claim 19, wherein, the conductive particles are conductive nanowire particles, and the conductive nanowire particles have a thickness of 100 nm to 200 nm and a length of 150 μm or less.

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