Method for forming dust-collecting layer on porous body without using binder

Abstract

To provide a manufacturing method for a filter element in which fine particles constituting a dust-collecting layer are not peeled off and high performance is maintained over a long period of time even when the filter element is scaled up.SOLUTION: A layer of fine particles containing low-melting-point fine particles and small-diameter fine particles is deposited and formed on the surface of a filter element material while sucking the filter element material, and the layer of fine particles is heated by heating means, exemplified by an infrared heater or an oven, to sinter the fine particles to form a dust-collecting layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a filter that has low pressure loss and good energy efficiency by forming a dust collection layer that has a certain strength while providing high collection performance without using a binder, and in particular to a method for manufacturing a filter that has excellent resistance to pulsed air during backwashing and maintains its performance for a long period of time even when scaled up. [Background technology]

[0002] The filter element of the dust collection filter is composed of a filter element material made of a resin sintered body and a dust collection layer made of resin fine particles. Depending on the specifications of the filter element, a conductive carbon layer may be added to the filter element.

[0003] The filter element material can be obtained by sintering synthetic resin powder using methods such as those described in Patent Documents 1 and 2, and the obtained sintered synthetic resin has voids between the individual synthetic resin particles that make up the synthetic resin powder, allowing air to pass through.

[0004] The dust collection layer of the filter element of a sinter lamellar filter is formed by suspending resin fine particles to be used as the dust collection layer in an aqueous solvent to prepare a coating liquid containing the resin fine particles to be used as the dust collection layer, applying the coating liquid to the surface of a filter element material made of a resin sintered body, and then drying the coating liquid.

[0005] In addition, in antistatic filter elements, conductive carbon powder is suspended in a water-based solvent to prepare a coating liquid containing the conductive carbon powder, and the carbon coating liquid is applied to the surface of a filter element material made of a resin sintered body and then dried to form a conductive carbon layer. Thereafter, a coating liquid containing resin fine particles to be used as a dust collection layer is applied and then dried to form a dust collection layer.

[0006] The resin fine particles used as the dust collection layer are selected from the resin material and particle size according to the property and particle size of the dust to be collected by the dust collection filter. The resin material used as the dust collection layer is selected from polyethylene (PE), polytetrafluoroethylene (PTFE), etc., and the resin particle size is selected from the range of 1 to 100 μm.

[0007] The dust collection layer is formed by individually stacking fine resin particles used in the collection layer, and has a structure in which there are gaps between the individual resin particles that make up the collection layer through which air can pass. Dust in dust-laden air containing the particles to be collected is captured by the dust collection layer, and clean air after the dust is collected by the dust collection layer passes through the gaps formed in the collection layer through which air can pass and the gaps in the filter element material, and flows into the inside of the filter element.

[0008] Here, the configuration of a typical dust collector and the process of removing dust from dust-laden air will be explained with reference to FIG. The dust collector 10 has a sealed casing 12, the inside of which is divided into a lower dust collection chamber 16 and an upper clean air chamber 18 by an upper top plate 14 which serves as a partition wall, and a dust-laden air supply port 20 which communicates with the lower dust collection chamber is provided halfway up the casing. A clean air outlet 22 which communicates with the clean air chamber is provided at the top of the casing. Furthermore, hollow, flat filter elements 24 are attached at predetermined intervals to the underside of the upper top plate, and a hopper 26 which discharges the removed dust and an outlet 28 for the dust are provided at the bottom of the casing.

[0009] As shown in Fig. 1 (2), the filter element 24 has a large diameter portion 32 formed at the upper end, which is bulged out to accommodate a frame 34. Both ends of the frame housed within the large diameter portion are attached to the upper top plate 14 together with the large diameter portion via tightening bolts 36. A packing 38 is interposed between the upper top plate and the frame.

[0010] As shown in the perspective view (FIG. 1(3)) of the PP cross section of the external view of the filter element, the inside of the filter element is formed with a plurality of hollow chambers 24a with open upper ends, and the dust-adhering surface of the element is corrugated or bellows-shaped to increase the adhesion area. Dust-containing air supplied from the dust-containing air supply port 20 into the dust collection chamber 16 of the casing passes through the filter body of the hollow filter element and flows inside. At this time, the powder to be collected adheres to and accumulates in the dust collection layer formed on the material surface of the filter element, and the clean air that has flowed inside the filter element passes through the passage of the frame and enters the clean air chamber 18 at the top of the casing, and is led to a specified location from its exhaust port 22.

[0011] When the dust-collecting layer formed on the surface of the filter element is filled with dust, the air passage is blocked and the pressure loss increases. Therefore, the filter elements 24 are backwashed at regular intervals to remove the dust that has been collected. That is, the backwash valves (not shown) are opened and closed at regular intervals by timer control or the like, and pulsed air for backwashing is sprayed from the corresponding spray pipes. As a result, the pulsed air flows backward from the inside to the outside of each filter element 24, and the dust that has been collected and collected on the dust-collecting layer is brushed off as it is without scattering. The brushed off dust is collected from the outlet 28 through the hopper 26.

[0012] Due to the synergistic effect of the above-mentioned dust collector device configuration, the process of removing dust from dust-laden air, and the configuration of the filter element, a filter element composed of a filter element material made of a resin sintered body and a dust collection layer made of resin fine particles has been widely adopted as an environmental dust collection means for dust-generating locations in mines, quarries, steelworks, and the like both in Japan and overseas, as a dust-collecting filter element that can be used continuously over a long period of time.

[0013] However, the dust collection layer formed by applying a conventional coating liquid to the surface of the filter element material is attached to the surface of the filter element material by the adhesive force of the water-soluble binder, so it is not very strong, and there was a concern that when the target powder that has adhered and accumulated on the dust collection layer is removed by backwashing with pulsed air, part of the dust collection layer may peel off, causing contamination of the target powder. Therefore, it could not be used in applications where prevention of contamination of food, etc. is important.

[0014] Furthermore, compared to general bag-type dust filters, the pressure loss (initial pressure loss) per filtration area at the start of operation is somewhat large, and this does not meet the needs of users who want to reduce initial costs. In light of this, there is a demand for the development of a dust collection layer that is stronger and has lower initial pressure loss as the layer to be formed on the surface of the filter element material made of a sintered resin.

[0015] As a method for solving the above technical problems, the present inventors developed a dry method for forming a dust collection layer without using a liquid binder (Patent Document 3). By using a filter element manufactured by this method, efficient dust collection with low pressure loss became possible compared to an element in which a dust collection layer is formed using a liquid binder.

[0016] In order to apply this low pressure loss filter element to a larger dust collector, the inventors manufactured a large filter element by the above-mentioned dust collection layer forming method and conducted a dust collection experiment while performing backwashing with pulsed air for long-term operation. Although the expected pressure loss was maintained at first, the pressure loss increased over time. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] JP 2003-126627 A [Patent Document 2] JP 2004-202326 A [Patent Document 3] Patent Publication No. 2022-022054 Summary of the Invention [Problem to be solved by the invention]

[0018] An object of the present invention is to provide a method for manufacturing a filter element in which a dust collection layer is formed on the surface of a filter element material made of a resin sintered body, which method maintains a strong and low initial pressure drop over a long period of time and can withstand scale-up. [Means for solving the problem]

[0019] The inventors of the present invention investigated the problems that occur when the prior art described in Patent Document 3 is scaled up in detail, and found that the increase in pressure loss is caused by the increase in the area to be heated with scale up, which leads to uneven temperature during heating and fusing, and the particles melt completely, resulting in the formation of areas with pores of a size close to that of the filter element material. When such areas with pores are formed, excessive airflow occurs in the areas, and the powder to be collected that cannot be removed by backwashing with pulsed air accumulates in the filter element material, eventually blocking the pores. When such blocked areas increase, the absolute number of pores in the filter decreases, which increases the airflow per pore, resulting in a vicious cycle in which the blocked areas gradually increase from areas with relatively large pores, leading to an increase in pressure loss. Furthermore, when backwashing with pulsed air, which is necessary for long-term operation, is performed intermittently, if the particles that make up the dust collection layer are larger in diameter than the powder to be collected, the fine particles of the powder to be collected will repeatedly break through the dust collection layer and accumulate within the filter element material, which was found to be another cause of increased pressure loss.

[0020] In view of the above problems, the inventors further conducted trial and error in determining a method of forming the dust collection layer. As a result, they discovered that by mixing particles having a low melting point with some of the particles forming the dust collection layer and setting the heating temperature when forming the dust collection layer to a temperature equal to or higher than the melting temperature of the particles with a low melting point and lower than the melting points of the particles of the filter element material and the other fine particles forming the dust collection layer, even if there are some temperature unevenness in various parts of the filter element material, the particles forming the dust collection layer can be reliably fused to each other by the low melting point particles, and further, by mixing fine particles with the particles forming the dust collection layer, it is possible to reduce the breakthrough of fine powder to be collected through the dust collection layer during backwashing with pulsed air, which led to the present invention.

[0021] Thus, the embodiments of the present invention are as follows. (1) A method for manufacturing a filter element, comprising: forming a layer of multiple types of fine particles on a surface of a filter element material, at least one of the multiple types having a melting point lower than that of the fine particles forming the filter element material and the dust collection layer; and heating the layer of fine particles with a heating means to sinter the fine particles and form a dust collection layer. (2) A method for manufacturing a filter element according to (1), wherein the particle size of one or more of the multiple types of particles is smaller than the particle size of the filter element material. (3) The method for manufacturing a filter element according to (1) or (2), wherein at least one type of particulate matter among the plurality of types of particulate matter that form the dust-trapping layer is smaller than the pores of the filter element material. (4) A method for manufacturing a filter element according to any one of (1) to (3), in which two or more types of fine particles of (1) are thoroughly mixed in advance and then sucked into a filter element material, forming the fine particles on the surface of the filter element material. (5) A method for manufacturing a filter element according to any one of (1) to (4), in which two or more types of particles (1) are separately absorbed into a filter element material and formed in a layer on its surface. (6) A method for producing a filter element according to any one of (1) to (5), wherein the heating means is an infrared heater or an oven. (7) A method for manufacturing a filter element (204) according to any one of (1) to (6), comprising forming a dust-trapping layer on the outer surface of a filter element (204) having an inner surface facing the inner space (208) and an outer surface oriented in the opposite direction to the inner space (208), the filter element (204) comprising at least one pocket-like structure or bag-like structure (310), the at least one pocket-like structure or bag-like structure (310) leaving at least one clean fluid outlet opening (212) and having an inner space (208) surrounded by at least one wall (210) of the filter element (204). (8) A method for manufacturing a filter element (204) according to any one of (1) to (6), comprising: forming a dust-collecting layer (202) on the inner surface of the filter element (204), the filter element (204) having at least one pocket-like structure or bag-like structure (310), the at least one pocket-like structure or bag-like structure (310) leaving at least one untreated fluid inlet opening (228) and having an internal space (208) surrounded by at least one wall (210) of the filter element (204), the filter element (204) having an inner surface facing the internal space (208) and an outer surface facing in the opposite direction to the internal space (208). (9) A method for manufacturing a filter element (204) according to any one of (1) to (8), wherein the filter element (204) is formed of at least one filter element wall (210) defining a lamellar structure (300), the lamellar structure (300) including a geometric configuration of protrusions (304) and recesses (306) on at least one of two opposing sides of the at least one filter element wall (210). (10) The method of manufacturing a filter element (204) according to (9), wherein the geometric configuration is defined by a plurality of protrusions (304) and recesses (306) on opposite sides of the at least one filter element wall (210). (11) The method of manufacturing a filter element (204) of (9) or (10), comprising shaping the protrusions (304) and recesses (306) of the at least one filter element wall (210) to form at least one undercut portion (308) of the geometric configuration. (12) A method for producing a filter element (204) according to any one of (9) to (11), wherein the geometric configuration of the lamellar structure is a spiral configuration (302). (13) The method for manufacturing a filter element (204) according to any one of (9) to (12), comprising: the filter element (204) being formed with at least one pocket-like or bag-like structure (310) having a cylindrical, conical, or other rotationally symmetric shape defined by the at least one filter element wall (210); and the protrusions (304) and recesses (306) of the at least one filter element wall (310) being formed to form the geometric shape of the lamellar structure (300). (14) A method for manufacturing a filter element (204) according to any one of (9) to (13), wherein one of the two or more types of fine particles constitutes a matrix material of the dust collection layer (202) and is made of the same resin material as the filter element material. (15) A method for producing a filter element (204) according to (14), comprising the step of: one of two types of fine particles constituting a matrix material of the dust-collecting layer (202) being polyethylene. (16) A method for producing a filter element (204) according to any one of (1) to (15), characterized in that the dust-collecting layer (202) is formed without using any binder or solvent. (17) The method for producing a filter element (204) according to any one of (1) to (16), wherein the two or more kinds of fine particles do not contain perfluoroalkoxyalkane (PFA). (18) A filter element (204) manufactured by the method according to any one of (1) to (17).

[0022] Examples of heating means for heating the layer of fine particles include heating means that irradiate heat rays and heating means that heat in a high-temperature atmosphere. An example of heating means that irradiates heat rays is an infrared heater, and an example of heating means that heats in a high-temperature atmosphere is a gear oven.

[0023] The particle size of the resin fine powder used in the dust collection layer can be selected from the range of 0.1 to 200 μm, and preferably the resin fine powder has an average particle size of 0.1 μm to 50 μm. The average particle size mentioned here refers to the D50 value measured with a particle size distribution measuring device such as a microtrack.

[0024] As the resin fine powder forming the dust collection layer, in addition to PTFE fine particles, ultra-high molecular weight polyethylene (GUR2126, manufactured by Celanese Japan) or low molecular weight polyethylene (Hi-Wax HP10A, manufactured by Mitsui Fine Chemicals, Inc.) is preferably used.

[0025] Furthermore, the temperature difference between the melting point of the low-melting point resin fine powder and the melting point of the other fine particles that form the dust collection layer need only be greater than the temperature unevenness that inevitably occurs due to the heating means used, and a low-melting point resin such as low molecular weight polyethylene can be used as the low-melting point fine particles.

[0026] Furthermore, among the fine particles that form the dust collection layer, high density polymers such as HDPE can be used for small diameter particles. In forming the dust collection layer, the amount of fine particles to be attached to the surface of the filter element material is 1 g to 100 g / m 2 An appropriate amount can be specified from the range of 30g to 60g / m 2 Attach within the range of.

[0027] If the amount of fine particles attached to the surface of the filter element material is small, they will not spread throughout the entire surface and the pores of the sintered body will not be filled sufficiently. If the amount is excessive, they will form lumps on the surface, causing an increase in initial pressure drop.

[0028] A simple method for attaching the fine particles to the surface of the filter element material is, for example, to apply the particles with a brush.

[0029] A tool like the one shown in Figure 3 is used to attach the fine particles that form the dust collection layer to the surface of the filter element material. The material for the two core elements is placed in the jig shown in Fig. 3, the fine particles that form the dust collection layer are placed on the bottom, and while sucking using a ring blower that is connected to the jig by piping, compressed air is blown in from the compressed air outlet 92 at the bottom of the jig to raise the particles up and distribute them thoroughly in the pores on the surface of the element. The fine particles that form the dust collection layer are either all mixed together or are not mixed and are deposited in layers in stages. The method for fixing the fine particles attached to the surface of the filter element material by the above method as a dust collection layer is to use a heating means such as an oven as shown in Figure 2. The fine particles are heated to the softening point of the particle with the lowest softening point, melting the fine particles and fusing them to the surface of the element material and to each other, completing the process. A dust-collecting layer is formed on the surface of the completed filter element material, as shown in Figure 5. After the pores of the filter element material are filled with the above-mentioned adhered fine particles, the fine particles that do not melt when heated remain in their particulate form, forming a dust-collecting layer with extremely fine pores, achieving both dust-collecting performance and suppression of initial pressure loss. The two-core element is a test filter of the filter element in the manner shown in FIG. 4, and has a structure equipped with two sets of hollow chambers (cores) with open upper ends inside the filter element material, and is an element material obtained by integral sintering or by bonding the components that make up the element together with an adhesive or the like.

[0030] The above-described method can be applied to form a dust-collecting layer on a filter element having at least one pocket-like or bag-like structure. A pocket-like or bag-like structure is characterized by forming an interior space surrounded by at least one wall. At least one wall has an opening to provide access to the interior space of the pocket- or bag-like structure from the outside for inserting or removing substances from the interior space.

[0031] The at least one pocket- or bag-like structure may have the shape of a pocket or bag having at least one clean fluid outlet opening and defining an interior space surrounded by at least one wall of the filter element. That is to say, with the exception of the clean fluid discharge opening or openings, the interior space of the pocket- or bag-like structure is surrounded by at least one filter element wall. Such a filter element has an inner surface facing the interior space of the pocket-like or bag-like structure. Such a filter element also has an exterior surface facing away from the interior space of the pocket or bag-like structure. When such a filter element is utilized, the method of forming the dust collection layer described herein would involve forming the dust collection layer on the outer surface of a pocket-like or bag-like structure. According to this, the particles forming the dust-collecting layer are attached to the surface of at least one wall of the filter element facing in the opposite direction of the internal space. What is important is that the dust-collecting layer is also applied to filter elements that are configured with a pocket-like or bag-like structure. In other words, if a filter element having a pocket-like or bag-like structure is formed before assembly, it is not necessary to form a filter element by assembling two or more filter element parts, each having a dust trapping layer laminated thereon, separately. Rather, according to the method described herein, the dust-collecting layer can be applied to the filter element on the outside of the pocket- or bag-like structure, or more precisely, already forming the pocket- or bag-like structure.

[0032] Additionally or alternatively, the at least one pocket- or bag-like structure may be in the form of a pocket or bag defining an interior space enclosed by at least one wall of the filter element while leaving at least one raw fluid inlet opening. In other words, the interior space of the pocket- or bag-like structure, except for the raw fluid inlet opening or openings, is surrounded by at least one filter element wall. Such a filter element has an inner surface facing the interior space of the pocket-like or bag-like structure. Such filter elements also have opposing exterior surfaces of the interior space of the pocket- or bag-like structure. When such a filter element is utilized, the method of forming the dust collection layer described herein would involve forming the dust collection layer on the inside of a pocket-like or bag-like structure. In this way, the particles forming the dust-collecting layer are attached to the surface of at least one wall of the filter element facing the interior space. Importantly, the dust collecting layer can be applied to a filter element that already has a pocket-like or bag-like structure. Furthermore, if a filter element having a pocket-like structure or a bag-like structure is formed before assembly, there is no need to form the filter element by assembling two or more filter element components each having a dust collection layer separately. Rather, the method described herein allows the dust-collecting layer to be formed on the surface of the filter element blank inside a pocket- or bag-like structure, or more precisely already forming the pocket- or bag-like structure.

[0033] Furthermore, the above-described method may be applied to form a dust-collecting layer on a surface of a filter element blank formed with at least one filter element wall defining a lamellar structure. The lamella structure comprises a geometric configuration of protrusions and recesses on at least one of two opposing sides of at least one filter element wall. In particular, the at least one filter element wall defining the lamellar structure may be the same filter element wall as the at least one filter element wall defining the pocket-like or bag-like structure.

[0034] In particular, the geometric configuration may be constituted by a plurality of protrusions and recesses on either side of the filter element wall.

[0035] In particular, the protrusions and recesses of at least one filter element wall may be shaped to form at least one undercut portion of the geometric configuration. Conventional application methods such as spraying and brushing are unable to apply a dust-collecting layer as a coating film uniformly to the surface of the filter element wall that forms the undercut portion, and therefore it is unavoidable that there will be areas in the undercut pores that are not coated or where the coating is inefficient. Using a special technique in which two or more types of fine particles are attached in powder form to a filter element and then one of the two or more types of fine particles is melted to obtain a dust-collecting material of sufficiently uniform thickness, a dust-collecting layer can be formed even in areas where undercuts are formed.

[0036] In a particular embodiment of the method of manufacturing a filter element as described herein, the geometric configuration of the lamellar structure is a helical structure. By applying a helical structure, a given volume of filter element can be made into a lamellar structure with a large surface area available for filtering. For example, in the case of a filter element with a pocket-like or bag-like structure, the area of ​​the filtering surface per unit of the internal space surrounded by the filter element wall will be particularly large. This increases the filtering efficiency per volume required by the filter element.

[0037] In particular, the filter element may be formed with at least one pocket-like or bag-like structure having a cylindrical, conical, or other rotationally symmetric shape. A pocket-like or bag-like structure having a cylindrical or conical shape is rotationally symmetrical about the longitudinal axis of the cylinder or cone. Instead of a cylindrical or conical shape, other shapes may be used that have the same rotational symmetry about the longitudinal axis. The shape of the filter element is defined by at least one filter element wall. The protrusions and recesses of at least one filter element wall are shaped to form the geometric configuration of the lamella structure. In particular, lamellar structures having a helical geometry are well suited for pocket- or bag-like structures having a cylindrical or conical shape.

[0038] In a particularly preferred embodiment, the method for manufacturing a filter element described herein allows the use of the same resin material as the filter element material to which one of the two or more types of particulates constituting the matrix material of the dust collection layer is attached. In this manner, a substantially uniform filter element can be produced in which the material used to form the body of the filter element (eg, a sintered polyethylene material) also forms the matrix of the dust trapping layer. In this context, the term "matrix of the dust trapping layer" refers to the materials or particulates that make up the structure of the dust trapping layer, rather than other materials such as additives or fillers that are added to the matrix.

[0039] In one example, one of the two types of particulates constituting the matrix material of the dust collection layer may be polyethylene.

[0040] In particular, in the method for producing a filter element described in this specification, the dust-collecting layer can be formed without using a binder or a solvent. In particular, the methods of manufacturing the filter elements described herein may be referred to as dry coating or powder coating methods. That is, one or more types of particulate matter of the dust collection layer are applied in powder form to the surface of the filter element material, but they may also be applied in a premixed form as a mixture of one or more types of particulate matter, or different types of particulate matter may be applied sequentially. No liquid binders or solvents are used in this process. Rather, at least one of the one or more types of particulates is melted by applying heat after the particulates have been powdered and are attached to the surface of the filter element material. This allows the properties of the dust trapping layer to be tuned much better than with traditional liquid-based coating methods. In particular, the application of one or more particulates in powder form to the surface of a filter element in combination with the use of the fluidized bed technology described herein allows for high quality coating of even layered structures that contain complex geometries such as undercuts. Furthermore, the method of manufacturing the filter element described herein does not require the use of perfluoroalkoxyalkanes (PFA) to form the dust-collecting layer. Therefore, in a specific embodiment, the two or more types of particulates forming the dust-collecting layer do not contain PFA, and in particular the two or more types of particulates do not contain polytetrafluoroethylene. As described herein, by using a binder or solvent-free method for forming and adhering the dust trapping layer to the surface of the filter element material, a completely PFA-free filter element can be obtained, which can be effectively cleaned by pressure pulses for an extended period of time. As the inventors have found, the pressure drop of a fluid passing through a filter element according to the present invention after a pressure wash cycle is initially relatively low and remains at a fairly low and stable level even over the extended useful life of the filter element.

[0041] The present invention relates to the method for producing a filter element as described above, as well as to the filter element produced by this method. Effect of the Invention

[0042] The dust collection layer formed by the technology of the present invention is more firmly fused to the filter element material than previous technologies, making it possible to not only clean with an air blower or high-pressure running water, but also to prevent contamination of the collected dust powder with the fine particles that make up the dust collection layer.

[0043] By adjusting the particle size of the fine particles that are attached to the surface of the filter element material as the fine particles that make up the dust collection layer, it is possible to adjust the size of the pores in the dust collection layer. Also, by mixing other particles in advance with the fine particles to be attached, it is possible to change the performance of the dust collection layer.

[0044] As a result, the present invention makes it possible to provide users with a filter having a pore size sufficient for required performance such as low pressure loss, etc. Furthermore, it is expected that the filter will prevent contamination of collected dust powder, develop new applications, and contribute to improving the efficiency and productivity of dust collector maintenance.

[0045] The above-mentioned method can be applied to form a dust-collecting layer on a filter element material surface having at least one pocket-like or bag-like structure. The dust collecting layer can be applied to the surface of the filter element material in a configuration that already forms a pocket-like or bag-like structure. This dust collection layer can be formed on the outside of the pocket-like or bag-like structure, on the inside of the pocket-like or bag-like structure, or on both, in a form that already forms a pocket-like or bag-like structure. A particular advantage of the method of the invention is that it allows a sufficiently uniform dust-trapping layer to be formed on the surface of the filter element blank, even when the surface comprises a surface topography which forms undercuts. Additionally, the same material, such as polyethylene, that is used to form the filter element blank can be used to form the matrix of the dust trapping layer. [Brief description of the drawings]

[0046] [Figure 1] (1) Appearance of a typical dust collector, (2) appearance of a filter element (sinter lamellar), and (3) perspective view of the PP cross section. [Diagram 2] Heating method (oven) [Diagram 3] Cross-sectional view of filter element material suction tool [Figure 4] 2 Core element material pictures [Diagram 5] Cross-sectional images of examples [Figure 6] Lab Load Test Device for 2 Core Elements [Figure 7] Load test equipment for full-scale filter elements [Figure 8] A graph showing the time course of pressure loss in a full-scale filter element, along with experimental results for a conventional example. [Figure 9] 1 shows a schematic diagram of a treatment box for forming a dust-trapping layer on the outside of a pocket- or bag-shaped filter element blank according to a further embodiment; [Figure 10] 10 shows a schematic cross-sectional view of a filter element manufactured using the processing box of FIG. 9. [Figure 11]1 shows a schematic diagram of a treatment box for forming a dust-trapping layer inside a pocket- or bag-shaped filter element material according to a further embodiment; [Figure 12] 12 shows a schematic cross-sectional view of a filter element manufactured using the processing box of FIG. 11. [Figure 13] 1 shows a schematic diagram of a treatment box for forming a dust-trapping layer on the inside of a pocket- or bag-shaped filter element blank according to a further embodiment. [Figure 14] 1A-1C show different views of a filter element blank on whose inside or outside a dust trapping layer can be formed according to any of the embodiments of the present invention. [Figure 15] 13A-13C show different views of further filter element blanks on whose inside or outside a dust trapping layer may be formed according to any of the embodiments of the present invention. [Figure 16] Graph showing the time course of pressure loss of the filter element of Example 9 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples. The filter element used in the examples and comparative examples of the present invention is a two-core integrated element. The two-core integrated element is a filter element for scale-up testing, which has two sets of hollow chambers inside the filter element. The two-core integrated element is obtained by forming the dust collection layer of the present invention on an element material obtained by integral sintering. EXAMPLES

[0048] The two-core element material was placed in the suction jig shown in Figure 3, and 5 g of mixed particles mixed at a weight ratio of LLDPE (linear low molecular weight PE, D50 = 45 μm): HDPE (high density PE, D50 = 10 μm): PTFE (D50 = 3.7 μm) = 5: 4: 1 was placed on the bottom. A ring blower was connected to the jig by piping, and while sucking at a filtration air speed of 2.0 m / min, compressed air was blown in from the compressed air outlet 92 at the bottom of the jig, causing the mixed particles to fly up and be sufficiently distributed in the pores on the surface of the element material. The mixture was heated and fused at an atmospheric temperature of 130 °C for 30 min using a gear oven (ACR45A, manufactured by Toyo Seiki Seisakusho Co., Ltd.) to produce a two-core filter element (filtration area 0.16 m) equipped with a dust collection layer. 2 ) was prepared. The two-core element obtained above was attached to a two-core element laboratory dust collection load test device (manufactured by Nittetsu Mining Co., Ltd., Figure 6). As the experimental dust collection powder, calcium carbonate powder for flue gas desulfurization (average particle size: 12 μm, manufactured by Nittetsu Mining Co., Ltd.) was used, and the filtration air velocity was 1 m / min (treatment air volume 0.16 m 3 / min), dust feed concentration (10g / m 3 The dust collection load confirmation test was carried out for 5 minutes under the conditions of . In the dust collection load confirmation test, the pressure loss (kPa) and the exhaust dust concentration (LD-3K2, Shibata Scientific Co., Ltd.) at the start and end of the test were evaluated. The results obtained are shown in the table below, along with the results of a similar experiment conducted on a filter element made using a classified product (D50 = 24 μm) of the low molecular weight polyethylene powder (Hiwax HP10A, manufactured by Mitsui Fine Chemicals) used in Example 8 of Patent Document 3. Although the pressure loss was slightly higher than that in Patent Document 3 (Example 8), the exhaust dust concentration was significantly lower. EXAMPLES

[0049] The actual size filter element prepared above was attached to a load test device for actual size filter elements (Fig. 7: manufactured by Nittetsu Mining) and a dust collection load confirmation test was carried out. The structure of the load test device for actual size filter elements is the same as that of the general dust collector shown in Fig. 1, and the inside of the sealed casing is divided into an upper clean air chamber 103 and a lower dust collection chamber 107 by an upper top plate 108, which serves as a partition wall. The dust collection powder used in the experiment was calcium carbonate powder for flue gas desulfurization (average particle size: 12 μm, manufactured by Nittetsu Mining). It was extracted by a constant quantity supply device 101 installed downstream of the upper tank 102 so that it had a predetermined dust content. It became dust-containing air in the piping and was filtered at a speed of 1 m / min (processing air volume 18 m 3 / min), dust feed concentration (5g / m 3 The dust-containing air flows into the dust collection chamber under the condition of (a) above. The dust-containing air is separated into dust and air by the test filter elements 106 that are installed in the dust collection chamber at a predetermined interval and number. The dust particles that adhere to and accumulate on the dust collection layer formed on the material surface of the filter element are swept down to a hopper 109 under the dust collection chamber at one-minute intervals by backwash pulse air of 0.5 MPa, and are stored in a lower tank 105 by a dust transport device 104. The experimental dust particles that have accumulated in the lower tank are transported to an upper tank by a pneumatic transport device (not shown). In the dust collection load confirmation test, the pressure loss (kPa) and the exhaust dust concentration (LD-3K2, Shibata Scientific Co., Ltd.) at the start and end of the test were evaluated. The test results are shown in Figure 8. From the graph in FIG. 8, it can be seen that although the filter element of this embodiment has a slightly higher initial pressure drop than Patent Document 3 (Example 8), this quickly reverses and the pressure drop remains significantly lower than that of the dust collection layer of the conventional technology. This is thought to be because, under the conditions of Patent Document 3 (Example 8), the low molecular weight PE fine particles melt, and the large particles that remain unmelted are responsible for forming the pores in the dust collection layer, whereas in the dust collection layer of this example, it is formed from a three-type mixed fine particle consisting of a mixture of two types of fine particles that do not melt at the heating temperature, and the fine particles that do not melt when heated contribute to the formation of extremely fine pores, resulting in the formation of a dust collection layer with fewer large pores that can cause gaps, although the initial pressure loss is high. EXAMPLES

[0050] The materials for the two core elements were placed in the suction jig shown in Figure 3, and the LLDPE, HDPE, and PTFE powders were placed individually at the bottom. A ring blower connected to the jig by piping was used to suck the particles at 2.0 m / min. Compressor air was then blown in from the compressed air outlet 92 at the bottom of the jig, causing the mixed particles to fly up and spread throughout the pores on the surface of the element materials. Specifically, first HDPE (D50 = 120 μm), then LLDPE (D50 = 20 μm), then HDPE (D50 = 10 μm), further LLDPE (D50 = 20 μm), and finally PTFE (D50 = 3.7 μm) particles were adhered to the surface of the element material, and then the elements were removed from the jig and heated and fused at an ambient temperature of 130°C for 30 minutes using a gear oven (ACR45A, manufactured by Toyo Seiki Seisakusho) to produce two core elements with dust collection layers.

[0051] The two-core element obtained above was attached to a two-core element laboratory dust collection load test device (manufactured by Nittetsu Mining Co., Ltd., Figure 6). As the experimental dust collection powder, calcium carbonate powder for flue gas desulfurization (average particle size: 12 μm, manufactured by Nittetsu Mining Co., Ltd.) was used, and the filtration air velocity was 1 m / min (treatment air volume 0.16 m 3 / min), dust feed concentration (10g / m 3 The dust collection load confirmation test was carried out for 5 minutes under the conditions of . In the dust collection load confirmation test, the pressure loss (kPa) and the exhaust dust concentration (LD-3K2, Shibata Scientific Co., Ltd.) at the start and end of the test were evaluated. As is clear from the table showing the results, in Example 3, the collection performance of Example 1 was maintained while a lower pressure loss was achieved.

[0052] [Table 1] EXAMPLES

[0053] FIG. 9 shows a schematic diagram of a treatment box 200 for forming a dust-trapping layer 202 on its outer pocket-like filter element material 206 according to a further embodiment. The processing box 200 includes a processing box housing 214 that completely encloses a processing volume 222 . The processing box housing 214 has an inlet opening 218 through which an aerosol comprising a carrier fluid and a powder mixture (i.e., a mixture of two or more types of particulates dispersed in a carrier fluid) can enter the processing space 222 (see arrow A). The processing box housing 214 further includes a mounting opening 216 for receiving and mounting a mounting flange 220 . A filter element blank 206 of a filter element 204 having a dust-trapping layer 202 is attached to the mounting flange 220 . In FIG. 9, the processing box housing 214 is depicted in a partially cut away configuration to better illustrate the processing volume 222 with the mounting flange 220 and filter element material 206 therein. The filter element blank 206, and thus the filter element 204, is formed with at least one pocket- or bag-like structure 310 having the shape of a pocket or bag (see FIGS. 14 and 15). The pocket or bag-like structure 310 defines the interior space 208 of the filter element blank 206 or filter element 204 . The interior space 208 is surrounded by at least one filter element wall 210 (see FIG. 10). At least one filter element wall 210 completely surrounds the interior space 208 except for at least one clean fluid outlet opening 212 . Thus, the filter element 204 has an inner surface facing toward the interior space 208 and an outer surface facing away from the interior space 208 . When the filter element wall 210 is made from a porous material (e.g., porous polyethylene), fluid (e.g., gas or air) enters the interior space 208 of the filter element 204 through the filter element wall 210 and exits the interior space 208 through the clear fluid exit opening 212. However, powder material (ie, one or more particulates dispersed in a carrier fluid injected through the inlet opening 218 ) cannot pass through the filter element wall 210 . The filter element body 206 with the mounting flange 220 is inserted into the mounting opening 216 and mounted such that the closed side of the filter element blank 206 extends into the processing space 222 and the clean fluid outlet 212 of the filter element 204 opens toward the outside of the processing box housing 214. In a configuration in which the mounting flange 220 provided on the filter element body blank is inserted into the mounting opening 216, as shown in Figure 9, the mounting opening 216 and the mounting flange 220, as well as the mounting flange 220 and the filter element wall 210, fluid-tightly seal the processing volume 222 from the environment of the processing box housing 214. Sealing means outside of common engineering practice, such as a seal ring, may also be used. 9, fluid can only exit the processing volume 222 through the clean fluid outlet 212 of the filter element 204, as indicated by arrow B in FIG. In the orientation of the filter element 204 and mounting flange 220 shown in FIG. 9 , the powder material cannot enter the interior space 208 of the filter element blank 206; rather, the powder material is deposited on the outside of the filter element blank 206 forming a dust trapping layer 202 on the outside of the filter element 204. Thus, in the processing box 200 of FIG. 9, the pocket- or bag-type filter element 204 is inserted into the processing box 200 with its outer surface exposed to the processing space 222 . Thus, the treatment chamber 200 of FIG. 9 is configured to form a dust-collecting layer 202 on the outer surface of a pocket-like filter element 204 . FIG. 10 shows a schematic cross-sectional view of a filter element 204 manufactured using the processing box of FIG. The process of forming the dust-trapping layer 202 on the outside of the pocket-shaped filter element 204 proceeds as follows: (i) An aerosol fluid of two or more types of finely divided mixed powder materials constituting the dust-collecting layer dispersed in a pressurized carrier fluid (e.g., air) is injected into the treatment space 222 through the inlet opening 218 (see arrow A). (ii) The clean fluid outlet 212 of the filter element body 206 is connected to a fan, blower, pump, or similar device, which draws a fluid flow (e.g., air) from the treatment space 222 through the filter element wall 210 and which no longer contains powder material. Rather, the powder material is applied to the exterior surface of the filter element blank 206 as fluid injected into the treatment space passes through the filter element wall 210 and into the treatment space 222 . (iii) Due to the suction action provided to the aerosol in the treatment space 222 by a fan, a blower or a pump connected to the cleaning fluid outlet 212 of the filter element 204 (see arrow B), the powder mixture dispersed in the carrier fluid in the treatment space 222 adheres to the outer surface of the filter element blank 206 (more precisely, to the outer surface of the filter element wall 210 facing the treatment space 222). A dust trapping layer 202 is formed on the exterior surface of the filter element 204 by applying a powder material to the filter element blank 206 . (iv) The processing box 200 includes a nozzle arrangement 226 that includes at least one conduit that includes a plurality of nozzles. A fluid pulse is injected into the processing volume 222 through the nozzle arrangement 226 (see arrow C). These fluid pulses further help to keep the aerosol of powder mixture dispersed in the carrier fluid in the processing space 222 well dispersed and uniformly mixed until application of the material for the dust collection layer 202 is complete. The provision of such a nozzle arrangement 226 is optional. This process makes it possible to provide a uniform distribution of powder material on the surface of the filter element wall 210, even when the filter element wall 210 has a complex surface shape, for example, when the filter element wall 210 has an undercut portion. For example, in the embodiment of the filter element blank 206 shown in FIGS. 14 and 15 , the filter element wall 210 forming the filter element blank 206 comprises a lamellar structure 300 having a complex surface geometry including a helical structure 302 of protrusions 304 and recesses 306 . The protrusions 304 and recesses 306 form an undercut portion of the exterior of the filter element blank 206 . The protrusions 304 and recesses 306 also form undercut portions in the interior of the filter element blank 206 . Rotation of the filter element 204 within the processing box 200 is an optional means. As a result, the above-described method utilizes a filtration-like process to deposit a powder mixture to form the dust-trapping layer 202 on the exterior surface of the filter element 204 . After the powder mixture for forming the dust-collecting layer 202 is applied to the outer surface of the filter element 204, the filter element 204 is removed from the treatment box 200 and subjected to a heat treatment as described with respect to the previous embodiments. This heat treatment melts one of the two or more types of particles contained in the powder mixture applied to the surface of the filter element material 206, and after the heat treatment is completed, the dust collection layer 202 is fixed to the filter element material 206. Also, with regard to heat treatment, see FIG. 2 and its description, as well as Example 1 above. EXAMPLES

[0054] FIG. 11 shows a schematic diagram of a treatment box 200 for forming a dust-collecting layer 202 on its inner pocket-like filter element 204 according to a further embodiment. FIG. 12 shows a schematic cross-sectional view of a filter element manufactured using the processing box of FIG. The processing box of FIG. 11 basically corresponds to the processing box of FIG. Therefore, in FIG. 11, the same reference numbers are used as shown in FIG. For components in FIG. 11 having the same reference numbers as FIG. 9, please refer to the description of FIG. 9 above unless otherwise specified. The differences between the embodiment of FIG. 11 and FIG. 9 are described below. Similar to FIG. 9, the processing box housing 200 has a mounting opening 216 for receiving and mounting a mounting flange 220 . A filter element blank 206 having a dust trapping layer 202 is attached to the mounting flange 220 . In FIG. 11, the processing box housing 214 is shown partially cut away to better show the processing volume 222 with the mounting flange 220 and filter element body 206 therein. In order to form the dust-collecting layer 202 inside the pocket- or bag-shaped filter element 204, the configuration of the mounting flange 220 is changed from that of FIG. 9, and the pocket- or bag-shaped filter element body 206 is attached to the mounting flange 220 by a different method. Unlike the mounting flange 220 of FIG. 9, the mounting flange 220 of FIG. The mounting flange receiver 230 provides an extension of the mounting flange 220 to the treatment box 222 and is configured to receive the filter element blank 206 of the filter element 202 to which the dust collection layer 202 is applied. 9, the filter element blank 206, and thus the filter element 204, is also formed with at least one pocket- or bag-like structure 310 having the shape of a pocket or bag. The pocket or bag-like structure 310 defines the interior space 208 of the filter element blank 206 or filter element 204 . The interior space 208 is surrounded by at least one filter element wall 210 (see FIG. 12). Thus, the filter element 204 has an inner surface facing the interior space 208 and an outer surface facing away from the interior space 208 . In particular, the same filter element material 206 used in the embodiment of FIG. 9 may be used in the embodiment of FIG. However, in the embodiment of FIG. 11 , the filter element blank 206 is mounted to the mounting flange receptacle 230 of the mounting flange 220 in a different orientation, i.e., such that at least one filter element wall 210 completely surrounds the interior space 208, except for the at least one raw fluid inlet opening 228. The raw fluid inlet opening 228 opens into the processing volume 222 . Thus, the aerosol (ie, the carrier fluid, e.g., gas or air, in which the powder mixture is dispersed) within the processing volume 222 flows into the interior volume 208 of the filter element material 206 via the raw fluid inlet opening 228 . When the filter element wall 210 is made from a porous material (e.g., porous polyethylene), the fluid phase of the aerosol (e.g., gas or air) can pass through the filter element wall 210 and into the space 234 formed between the outer surface of the filter element blank 206 and the mounting flange receptacle 230. The space 234 is fluidly connected to a fan, blower, or pump that draws fluid from the space 234 through a mounting flange outlet 238 . In a configuration in which the mounting flange receiver 230 with the filter element blank 206 inserted therein is mounted within the mounting opening 216, as shown in Figure 11, the mounting opening 216 and the mounting flange 220 fluid-tight seal the processing volume 222 to the environment of the process box housing 214, and the mounting flange receiver 230 and the filter element blank 206 fluid-tight seal the processing volume 222 to a space 234 formed between the outer side of the filter element blank 206 and the mounting flange receiver 230. Sealing means outside of common engineering practice, such as a seal ring, may also be used. Thus, in the configuration shown in FIG. 11, fluid can pass through the filter element wall 210, reach the space 234 formed between the outside of the filter element blank 206 and the mounting flange receiver 230, and then exit the processing space 222 only through the mounting flange outlet 238, as shown by arrow B in FIG. 11. However, since the filter element wall 210 is not permeable to the powder material, the powder material cannot escape from the processing volume 222 at all. Similar to the orientation of the filter element 204 and mounting flange 220 shown in FIG. 11 , only the fluid phase of the aerosol injected into the processing space 222 can pass through the filter element wall 210, while the powder material (i.e., one or more particulates dispersed in a carrier fluid injected through the inlet opening 218) cannot pass through the filter element wall 210 and the powder material adheres to the inside of the filter element blank 206. As the powder adheres to the inside of the filter element 204 , a dust trapping layer 202 is formed on the inside of the filter element 204 . Thus, in the processing box 200 of FIG. 11, the pocket- or bag-shaped filter element 204 is inserted into the processing box 200 with its inside exposed to the processing space 222 . Therefore, the treatment box 200 of FIG. 11 is configured to form a dust-collecting layer 202 on the inside of the pocket-like filter element 204 . FIG. 12 shows a schematic cross-sectional view of a filter element manufactured using the processing box of FIG. The remaining process steps are the same as those described above with respect to the embodiment of FIGS. The dust-collecting layer 202 is fixed to the filter element material 206 by referring to the above steps (i) to (iv) and the subsequent heating step. EXAMPLES

[0055] FIG. 13 shows a schematic diagram of a treatment box 200 for forming a dust-collecting layer 202 on its inner pocket-like filter element 204 according to a further embodiment. FIG. 10 shows a schematic cross-sectional view of a filter element manufactured using the processing box of FIG. The processing box of FIG. 13 basically corresponds to the processing box of FIG. Therefore, in FIG. 13, the same reference numbers are used as in FIG. Unless otherwise stated, for components in FIG. 13 having the same reference numbers as those shown in FIG. 11, please refer to the description of FIG. 11 above. The differences between the embodiment of FIG. 13 and that of FIG. 11 are described below. Similar to that shown with respect to FIG. 11, the filter element blank 206, and thus the filter element 204, is also formed with at least one pocket- or bag-like structure 310 having the shape of a pocket or bag. The pocket or bag-like structure 310 defines the interior space 208 of the filter element blank 206 or filter element 204 . The interior space 208 is surrounded by at least one filter element wall 210 (see FIG. 12). Thus, the filter element 204 has an inner surface facing toward the interior space 208 and an outer surface facing away from the interior space 208 . In particular, the same filter element material 206 used in the embodiment of FIGS. 11 and 12 may be used in the embodiment of FIG. However, in the embodiment of FIG. 13, the filter element blank 206 is mounted to the mounting flange 220, i.e., from the exterior of the process box housing 214, and oriented such that at least one filter element wall 210 completely surrounds the interior space 208, except for at least one raw fluid inlet opening 228. The raw fluid inlet opening 228 opens into the processing volume 222 . Thus, the aerosol (i.e., the carrier fluid, e.g., gas or air, in which the powder mixture is dispersed) within the processing volume 222 can enter the interior volume 208 of the filter element material 206 via the raw fluid inlet opening 228 . The filter element wall 210 is made of a porous material (e.g., porous polyethylene) so that the fluid phase of the aerosol (e.g., gas or air) can pass through the filter element wall 210 and into the exterior space outside the filter element 204. From the exterior space outside the filter element 204, the fluid phase is aspirated by the action of a fan, blower, or pump 238 that draws fluid from the exterior space. For example, the treatment box housing 214 and the filter element 204 can be inserted into a second housing 236 connected to said fan, blower, or pump 238. The embodiment of FIG. 13 does not require a mounting flange receiver 230 as described with respect to the embodiment of FIG. In the treatment box 200 of Figure 13, a pocket-shaped or bag-shaped filter element 204 is attached to the treatment box 200 by mounting it on the treatment box housing 214 so that its inside is exposed to the treatment space 222, similar to the treatment box 200 of Figure 11. Therefore, the process chamber 200 of FIG. 13 is configured to form a dust-collecting layer 202 on the inside of the pocket-shaped filter element 204 . The remaining process steps are the same as those described above for the embodiment of FIGS. The dust-collecting layer 202 is fixed to the filter element body 206 by referring to the above steps (i) to (v) and the subsequent heating step. EXAMPLES

[0056] FIG. 14 shows three different perspective views of a filter element blank 206 on whose interior and / or exterior a dust trapping layer 202 may be applied, according to any embodiment of the present invention. The filter element blank 206, and thus the filter element 204, is formed in a pocket- or bag-like structure 310 having the shape of a pocket or bag. The pocket or bag-like structure 310 defines the interior space 208 of the filter element blank 206 or filter element 204 . The interior space 208 is surrounded by at least one filter element wall 210 (see FIG. 10 or 12). Thus, the filter element 204 or filter element blank 206 has an inner side facing toward the interior space 208 and an outer side facing away from the interior space 208 . As described in the fourth embodiment, the dust-collecting layer 202 can be formed on the outer surface of the filter element material 206 to manufacture a filter element having the dust-collecting layer 202 on its outer surface. Alternatively, or additionally, the dust trapping layer 202 may be formed on the inside of the filter element material 206 to produce a filter element having the dust trapping layer 202 on the inner side, as described with respect to Examples 5 and 6. The filter element blank 206 is formed with at least one filter element wall 210 that defines a lamellar structure 300 . The lamella structure 300 comprises a complex geometric arrangement of protrusions 304 and recesses 306 on the exterior of at least one filter element wall 210 . Alternatively, the lamella configuration 300 may include a complex geometric configuration of protrusions 304 and recesses 306 , with at least the recesses 306 on the inside of at least one filter element wall 210 . In particular, as shown in FIG. 14, the lamella structure 300 comprises a complementary geometric configuration comprised of a plurality of protrusions 304 and recesses 306 on both the exterior and interior sides of at least one filter element wall 210 . The protrusions 304 and recesses 306 of at least one filter element wall 210 are shaped to form at least one undercut portion 308 of the geometric configuration. A particular advantage of the filter element wall 210 defining the lamellar structure 300 is that it may provide a relatively large filter surface area for a given volume of filter element material 206 . However, applying a dust-trapping layer to the surface of such a filter element blank 206 is usually difficult, especially when the lamella structure 300 comprises an undercut portion 308 or comprises multiple undercut portions 308 . Conventional coating methods have been unable to form a sufficiently uniform dust-trapping layer 202 on a filter element material 206 having such a complex geometric configuration. However, the dry coating method according to the present invention, as described herein, provides for the first time a method for forming a sufficiently uniform dust-trapping layer 202 on a filter element blank 206 having a complex geometric configuration, such as a lamellar configuration 300 having protrusions 304 and recesses 306 with at least one undercut portion 308. In the embodiment shown in FIG. 14, the geometric configuration of the lamellar structure is a helical configuration 302 . The protrusions 304 and recesses 306 of at least one filter element wall 210 are shaped to form a helical configuration of the lamellar structure. The filter element blank 206, and thus the filter element 204, is also formed of at least one pocket-like or bag-like structure 310 having a cylindrical shape. In other embodiments, the filter element blank 206 , and thus the filter element 204 , may also be formed having a conical, frusto-conical, or other rotationally symmetric shape defined by at least one filter element wall 210 . The term “rotationally symmetric shape” is intended to denote any shape that has rotational symmetry along the longitudinal axis of the filter element blank 206 . Filter element blanks 206 having such complex geometric shapes can be manufactured through a sintering process, for example, by sintering polymer particles, particularly polyethylene particles. EXAMPLES

[0057] FIG. 15 shows different views of a further filter element material 206 on the inside and / or outside of which a dust trapping layer 202 may be formed, according to any embodiment of the present invention. In the embodiment of FIG. 15, the filter element blank 206 , and thus the filter element 204 , is formed from a plurality of pocket-like or bag-like structures 310 . Each of these pocket- or bag-like structures 310 has the shape of a pocket or a bag. The pocket or bag-like structure 310 defines an interior space 208 of the filter element blank 206 or filter element 204 . The interior space 208 is surrounded by at least one filter element wall 210 . Thus, the filter element 204 or filter element blank 206 has an inner surface facing toward the interior space 208 and an outer surface facing away from the interior space 208 . The considerations discussed above with respect to FIG. 14 also apply with respect to the embodiment of FIG. 15, and reference is made to those discussions as well. EXAMPLES

[0058] According to Example 4, a filter element was manufactured by subjecting a cylindrical filter element material to a treatment for forming a dust-collecting layer in a treatment chamber. Next, a dust collection load confirmation test was carried out on this filter element using the dust collection load test device shown in FIG. The filter element material was made by sintering polyethylene particles. The filter element blank had a cylindrical shape with a generally cylindrical filter element wall. The generally cylindrical filter element wall was provided with a lamellar structure having a helical shape. The lamellar structure was formed by a number of spiral protrusions and recesses, as shown in FIG. The filter element body had a diameter of 137 mm and a length of 220 mm. After the filter element body was inserted into the treatment chamber of FIG. 14, the particulate mixture was flowed into the treatment chamber to form a dust-collecting layer on the filter element body. The particulate mixture was made of 60 wt% LLDPE (linear low density polyethylene, D50 = 45 μm) and 40 wt% UHMWPE (ultra-high molecular weight polyethylene, D50 = 10 μm). The mixture did not contain PTFE. Processing steps followed those described with respect to Example 1 and above with respect to Example 4. The filter element we created is 0.15m 2 The filter surface was 100 mm. The filter element was inserted into the dust collection load test device shown in FIG. The test parameters were as follows: Filter surface: 0.15 m 2 Dust load: 1.5kg clay slate, equivalent to a volume of 2.0L Air volume: 107.1m 3 / s (Test start) ~84m 3 / s (Exam End) Dust mass flow rate: 60 g / s Dust feed concentration: 2017.0 g / m 3 Pulse cleaning cycle: 28 seconds Pulse Cleansing Duration: 2 seconds Cleaning pulse pressure: 0.9 bar Test duration: 2880 cycles = 191 hours Total amount of dust transported: 34380 kg The filter element pressure drop after the pressure wash cycle was as follows: Initial pressure loss: 1750 Pa Pressure loss after 5 minutes: 2650 Pa Pressure loss after 30 minutes: 2800 Pa Pressure loss after 1 hour: 3600 Pa Pressure loss after 2 hours: 3850 Pa Pressure loss after 17 hours: 5450 Pa Pressure loss after 41 hours: 6150 Pa Pressure loss after 43 hours: 6150 Pa Pressure loss after 67 hours: 6400 Pa Pressure loss after 89 hours: 6600 Pa Pressure loss after 161 hours: 6600 Pa Pressure loss after 185 hours: 6600 Pa Pressure loss after 191 hours: 6600 Pa The above pressure loss over time is graphed and shown in FIG. The maximum dust concentrations measured in the clean gas downstream of the filter element were: After 10 minutes: 0.099 mg / m 2 After 1 hour: 0071 mg / m 2 After 43 hours: 0.099 mg / m 2 Dust concentrations were measured by a Hund™ Data II instrument manufactured by Helmut Hund GmbH, Wetzlar, Germany. After dismantling the filter element from the dust load test apparatus, no traces of dust material were found mixed into the filter element material. [Explanation of symbols]

[0059] 10 Sinter lamellar dust collector 12 Casing 14 Top plate 16 Dust collection chamber 18 Clean Air Room 20 Dust-containing air supply port 22 Clean air outlet 24 Filter element 24a Hollow Room 26 Hopper 28 Dust outlet 32 Large diameter section 34 Frames 36 Fastening bolt 38 Packing 91 Aerosol outlet 92 Compressed air outlet 93 Powder constituting dust collection layer 100 Fans 101 Quantitative feeding device 102 Upper Tank 103 Upper clean air chamber 104 Dust conveying device 105 Lower Tank 106 Test filter element 107 Lower dust collection chamber 108 Top plate 109 Hopper 200 Processing box 202 Dust collection layer 204 Filter element 206 Filter element material 208 Interior Space 210 Filter element wall 212 Clean air outlet 214 Processing box housing 216 Mounting hole 218 Fluid Inlet 220 Mounting flange 222 Processing Space 226 Nozzle Device 228 Raw material fluid inlet opening 230 Mounting flange receiver 234 Space between filter element and mounting flange 236 Second Housing 238 Pump 300 Lamella structure 302 Spiral structure 304 Protrusion 306 Recess 308 Undercut section 310 Pocket or bag structure

Claims

1. thoroughly mixing two or more types of microparticles; forming a binder- and / or solvent-free particulate layer of two or more types of particulates on a surface of a filter element material; A step of melting one or more of the two or more types of fine particles by heating; forming a dust-collecting layer after cooling; Among the two or more kinds of particles, the melting point of one or more kinds of particles is lower than the melting points of the other particles and particles constituting the filter element material; The one or more types of fine particles are solidified after melting and are firmly bonded to other fine particles and filament materials, The filter element material is a resin sintered body, The method for producing a filter element, wherein the fine particles are made of a material selected from polyethylene-based resins.

2. The method for producing a filter element according to claim 1 , wherein the particle diameter of one or more of the two or more types of fine particles is smaller than that of a resin constituting a filter element material.

3. The method for producing a filter element according to claim 1 , wherein the particulate is a powder particulate.

4. 2. The method for manufacturing a filter element according to claim 1, wherein each of the two or more types of particulates is formed in a step-like layer on the surface of the filter element material to form a mixed particulate layer consisting of a plurality of particulate layers.

5. Before forming the fine particle layer, the two or more types of fine particles are thoroughly mixed in advance, and then The method for manufacturing a filter element according to claim 1 , further comprising the steps of: sucking the two or more types of particulates into the filter element material to form the particulate layer on a surface of the filter element material.

6. The method for manufacturing a filter element according to claim 1 , further comprising the steps of: sucking the two or more types of particulate matter separately into the filter element material to form the particulate matter layer in a layer shape on the surface of the filter element material.

7. In the heating step, the one or more types of fine particles are melted by a heating means, The method for producing a filter element according to claim 1 , wherein the heating means is an infrared heater or an oven.

8. The filter element (204) comprises at least one pocket-like or bag-like structure (310); the at least one pocket-like or bag-like structure (310) has an interior space (208) surrounded by at least one filter element wall (210) of the filter element (204) leaving at least one clean fluid outlet opening (212); forming a dust-collecting layer on an outer surface of a filter element (204) having an inner surface facing the interior space (208) and an outer surface oriented in an opposite direction to the interior space (208); A method for manufacturing the filter element (204) of claim 1.

9. The filter element (204) comprises at least one pocket-like or bag-like structure (310); the at least one pocket-like or bag-like structure (310) has an interior space (208) bounded by at least one filter element wall (210) of the filter element (204) leaving at least one raw fluid inlet opening (228); the filter element (204) has an inner surface facing the internal space (208) and an outer surface facing in a direction opposite to the internal space (208), and a dust-trapping layer (202) is formed on the inner surface of the filter element (204). A method for manufacturing the filter element (204) of claim 1.

10. The filter element (204) is formed of at least one filter element wall (210) that defines a lamellar structure (300); 2. The method of claim 1, wherein the lamellar structure includes a geometric configuration on at least one of two opposing sides of the at least one filter element wall.

11. 11. The method of claim 10, wherein the geometric configuration comprises a plurality of protrusions (304) and recesses (306) on opposite sides of the at least one filter element wall (210).

12. 12. The method of claim 11, further comprising shaping the plurality of protrusions (304) and recesses (306) of the at least one filter element wall (210) to form at least one undercut portion (308) of the geometric configuration.

13. The method of claim 10, wherein the geometric configuration of the lamellar structure is a helical configuration.

14. the filter element (204) is formed with at least one pocket-like or bag-like structure (310) having a cylindrical, conical, or other rotationally symmetric shape defined by the at least one filter element wall (210); 12. The method of claim 11, further comprising forming the plurality of protrusions (304) and recesses (306) of the at least one filter element wall (210) to form a geometric configuration of the lamella structure (300).

15. 2. The method of claim 1, wherein one of the two or more types of particulates constitutes a matrix material of the dust trapping layer and is made of the same resin material as the filter element material.

16. The method of claim 14, further comprising the step of: forming a matrix material of the dust-collecting layer (202) from one of two types of particulate matter, the matrix material being polyethylene.

17. A method for manufacturing a filter element as described in claim 1, wherein the fine particles are a material selected from the group consisting of LDPE, HDPE, and PTFE.

18. The method of claim 1, wherein the two or more types of particulates do not include perfluoroalkoxyalkanes (PFAs).

19. A filter element material, A filter element comprising: a dust collection layer formed on a surface of the filter element material, The dust-collecting layer is a fine particle layer that does not contain a binder and is made of two or more types of fine particles that are thoroughly mixed together, Among the two or more kinds of particles, the melting point of one or more kinds of particles is lower than the melting points of the other particles and the particles constituting the filter element material, and the one or more kinds of particles are firmly bonded to the other particles by melting and solidifying; The filter element material is a resin sintered body, The filter element, wherein the particulate is a material selected from the group consisting of LDPE, HDPE, and PTFE.

Images