JP7624036B2 - Method for forming dust-collecting layer on porous body without using binder - Google Patents

Description

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. In particular, the present invention relates 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.

The filter element of a 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.

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 resulting sintered synthetic resin has gaps between the individual synthetic resin particles that make up the synthetic resin. The gaps allow air to pass through.

The dust collection layer of the filter element of the sinter lamellar filter is formed by suspending the 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 the filter element material made of a resin sintered body, and then drying the coating liquid.

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 the filter element material made of a resin sintered body and then dried to form a conductive carbon layer. After that, 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.

The resin material and particle size of the resin particles used as the dust collection layer are selected according to the properties and particle size of the dust to be collected using 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.

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 the dust-laden air containing the particles to be collected is captured by the dust collection layer, and the 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.

Here, the configuration of a general dust collector and the process of removing dust from dust-laden air will be described with reference to FIG.
The dust collector 10 has a sealed casing 12, the interior 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 for discharging the removed dust and an outlet 28 for the dust are provided at the bottom of the casing.

As shown in FIG. 1 (2), the filter element 24 has a large diameter portion 32 at the upper end, which is formed into a bulging shape to accommodate a frame 34. Both ends of the frame housed in the large diameter portion are attached to the upper top plate 14 integrally with the large diameter portion via tightening bolts 36. A packing 38 is interposed between the upper top plate and the frame.

As shown in the perspective view (Figure 1 (3)) of the P-P cross section of the filter element's external view, the inside of the filter element is formed with multiple 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-laden air supplied from the dust-laden 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 captured adheres to and accumulates in the dust-capturing layer formed on the material surface of the filter element, and the clean air that flows 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.

When the dust-collecting layer formed on the surface of the filter element is filled with dust, the air passage is blocked and 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 without scattering. The brushed off dust is collected from the outlet 28 through the hopper 26.

The synergistic effect of the above-mentioned dust collector device configuration, the process of removing dust from dust-laden air, and the filter element configuration makes the filter element, which is made of a filter element material made of a resin sintered body and a dust-collecting layer made of resin fine particles, a dust-collecting filter element that can be used continuously for long periods of time, and has been widely adopted as an environmental dust collection method for dust-generating locations in mines, quarries, steelworks, etc., both in Japan and overseas.

However, the dust collection layer formed by applying a conventional coating liquid to the surface of the filter element material is adhered to the surface of the filter element material by the adhesive force of the water-soluble binder, and therefore is not very strong. There was concern that when the powder to be collected that has adhered to 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 powder to be collected. For this reason, it could not be used in applications where prevention of contamination of food, etc. is important.

Furthermore, compared to typical 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. Given this background, there is a demand for the development of a dust collection layer that is stronger and has lower initial pressure loss, to be formed on the surface of the filter element material made of sintered resin.

As a method for solving the above technical problems, the inventors have 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 is possible with low pressure loss compared to an element in which a dust collection layer is formed using a liquid binder.

In order to apply this low pressure loss filter element to a larger dust collector, the inventors manufactured a large filter element using the above dust collection layer formation method, and conducted dust collection experiments while backwashing with pulsed air for long-term operation. Although the expected pressure loss was initially maintained, the pressure loss increased over time.

JP 2003-126627 A JP 2004-202326 A Patent Publication No. 2022-022054

The object of the present invention is to provide a method for manufacturing a filter element in which a dust-collecting layer is formed on the surface of a filter element material made of a resin sintered body, and which maintains a strong and low initial pressure loss for a long period of time and can withstand scale-up.

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.

In view of the above problems, the inventors of the present invention have further studied the method of forming the dust collection layer through trial and error. As a result, they have discovered that by mixing particles with 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 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 together 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.

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 to form a dust collection layer.
(2) The method for manufacturing a filter element according to (1), wherein the particle diameter of one or more of the plurality of types of particles is smaller than the particle diameter of the filter element material.
(3) The method for producing a filter element according to (1) or (2), wherein at least one type of particulates forming the dust-collecting layer among the plurality of types of particulates 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 according to (1) are separately absorbed into a filter element material and formed in a layer on the surface thereof.
(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 method including forming an inner surface of the filter element (204) facing the inner space (208) and an outer surface facing the opposite direction of the inner space (208 ... an inner surface of the filter element (204) facing the inner space (208) and an outer surface facing the opposite direction of the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the inner space (208), the method including forming an inner surface of the filter element (204) facing the
(9) The 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) The 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 helical configuration (302).
(13) The method for manufacturing a filter element (204) according to any one of (9) to (12), comprising forming the filter element (204) with at least one pocket- 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 forming protrusions (304) and recesses (306) of the at least one filter element wall (310) 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), wherein one of the two types of fine particles constituting the matrix material of the dust collection layer (202) is polyethylene.
(16) A method for manufacturing a filter element (204) according to any one of (1) to (15), characterized in that the formation of the dust-collecting layer (202) is carried out 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 types 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).

Examples of the heating means for heating the layer of fine particles include a heating means for irradiating heat rays and a heating means for heating in a high-temperature atmosphere. An example of the heating means for irradiating heat rays is an infrared heater, and an example of the heating means for heating in a high-temperature atmosphere is a gear oven.

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 it is preferable to use resin fine powder with 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 Microtrac.

As the resin fine powder that forms 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.) are preferably used.

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 only needs to 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.

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-collecting layer, the amount of fine particles to be attached to the surface of the filter element material can be appropriately specified within the range of 1 g to 100 g/ ^m2 , and more preferably within the range of 30 g to 60 g/ ^m2 .

If the amount of fine particles attached to the surface of the filter element material is small, they will not spread throughout and the pores of the sintered body will not be fully filled. If there is too much, they will form lumps on the surface, causing an increase in initial pressure drop.

A simple way to attach the fine particles to the surface of the filter element material is to apply it with a brush, for example.

As a method for adhering the fine particles that form the dust-collecting layer to the surface of the filter element material, a tool as shown in FIG. 3 is used.
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 adhered fine particles, those particles that do not melt when heated remain in 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 including 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 together the members constituting the element with an adhesive or the like.

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.

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, the interior space of the pocket- or bag-like structure, except for the clean fluid discharge 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 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.

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 components of two or more filter elements 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.

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.

In particular, the geometric configuration can be formed by a number of protrusions and recesses on both sides of the filter element wall.

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 particulate matter are attached in powder form to a filter element and then one of the two or more types of particulate matter 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.

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.

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.

In a particularly preferred embodiment, by using the method for manufacturing a filter element described in this specification, it is possible to use 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 collection layer" refers to the materials or particulates that make up the structure of the dust collection layer, rather than other materials such as additives or fillers that are added to the matrix.

In one example, one of the two types of particulates that make up the matrix material of the dust collection layer may be polyethylene.

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 to the surface of the filter element material in powder form, 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 in powder form and are applied 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.
Additionally, the method of manufacturing the filter element described herein does not require the use of perfluoroalkoxyalkanes (PFA) to form the dust-collecting layer.
Thus, 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.

The present invention relates to the above-mentioned method for manufacturing a filter element, as well as to a filter element manufactured by this method.

The dust collection layer formed by the technology of the present invention is more strongly fused to the filter element material than previous technologies, making it possible to clean with air blowing or high-pressure running water, and also preventing contamination of the collected dust powder with the fine particles that make up the dust collection layer.

By adjusting the particle size of the fine particles that are attached to the surface of the filter element material to form the dust collection layer, it is possible to adjust the size of the pores in the dust collection layer. It is also possible to change the performance of the dust collection layer by mixing other particles in advance with the fine particles that are attached.

As a result, the present invention makes it possible to provide users with filters with pore sizes that are sufficient to meet required performance requirements, such as low pressure loss. Furthermore, it is expected to prevent contamination of collected dust powder, leading to the development of new applications and contributing to the improvement of the efficiency and productivity of dust collector maintenance.

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.

(1) An external view of a typical dust collector, (2) an external view of a filter element (sinter lamellar), and (3) a perspective view of the P-P cross section. Heating method (oven) Cross-sectional view of filter element material suction tool 2 Core element material pictures Cross-sectional images of examples Lab Load Test Device for 2 Core Elements Load test equipment for full-scale filter elements A graph showing the time course of pressure loss in a full-scale filter element, along with experimental results for a conventional example. 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; 10 shows a schematic cross-sectional view of a filter element manufactured using the processing box of FIG. 9. 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; 12 shows a schematic cross-sectional view of a filter element manufactured using the processing box of FIG. 11. 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. 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. 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. Graph showing the time course of pressure loss of the filter element of Example 9

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.

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, and compressed air was blown from the compressed air outlet 92 at the bottom of the jig while sucking at a filtration air speed of 2.0 m / min using a ring blower arranged in communication with the jig by piping, and the mixed particles were lifted up and sufficiently distributed to the pores on the surface of the element material. The mixture was heated and fused at an atmospheric temperature of 130 ° C for 30 minutes using a gear oven (ACR45A, manufactured by Toyo Seiki Seisakusho Co., Ltd.) to produce a two-core filter element (filtration area 0.16 m ² ) with a dust collection layer.
The two-core element obtained above was attached to a two-core element laboratory dust collection load test device (Nitetsu Mining, Figure 6), and a dust collection load confirmation test was performed for 5 minutes under conditions of a filtration air speed of 1 m/min (treatment air volume 0.16 ^m3 /min) and dust feed concentration (10 g/ ^m3 ) using calcium carbonate powder for flue gas desulfurization (average particle size: 12 μm, Nittetsu Mining) as the experimental dust collection powder. In the dust collection load confirmation test, the pressure loss (kPa) and exhaust dust concentration (LD-3K2, Shibata Scientific) 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 (Hi-Wax HP10A, manufactured by Mitsui Fine Chemicals, Inc.) used in Example 8 of Patent Document 3.
Although the pressure loss was slightly higher than that of Patent Document 3 (Example 8), the exhaust dust concentration was significantly lower.

The actual size filter element prepared above was attached to a load test device for actual size filter elements (Figure 7: manufactured by Nittetsu Mining Co., Ltd.) 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 Figure 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 is a partition wall.
The experimental dust collection powder used was calcium carbonate powder for flue gas desulfurization (average particle size: 12 μm, manufactured by Nittetsu Mining Co., Ltd.), which was extracted to a predetermined dust content by a constant volume feeder 101 installed downstream of an upper tank 102, became dust-laden air in the piping, and flowed into the dust collection chamber under conditions of a filtered air velocity of 1 m/min (processing air volume 18 ^m3 /min) and a dust feed concentration of 5 g/ ^m3 . The dust-laden air was separated into dust and air by test filter elements 106 installed in the dust collection chamber at predetermined intervals and in a predetermined 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 FIG.
From the graph in FIG. 8, it can be seen that the filter element of this embodiment has a slightly higher initial pressure drop than that of Patent Document 3 (Example 8), but 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, the layer 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 a dust collection layer with a high initial pressure loss but with fewer large pores that could cause gaps.

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 material. Specifically, first the particles were attached to the surface of the element material in the following order: HDPE (D50 = 120 μm), then LLDPE (D50 = 20 μm), then HDPE (D50 = 10 μm), then LLDPE (D50 = 20 μm), and finally PTFE (D50 = 3.7 μm). The particles were then removed from the jig and heated and fused at an ambient temperature of 130°C for 30 minutes in a gear oven (ACR45A, manufactured by Toyo Seiki Seisakusho) to produce two core elements with dust collection layers.

The two-core element obtained above was attached to a two-core element laboratory dust collection load test device (Nitetsu Mining, Figure 6), and a dust collection load confirmation test was performed for 5 minutes under conditions of a filtration air velocity of 1 m/min (treatment air volume 0.16 ^m3 /min) and dust feed concentration (10 g/ ^m3 ) using calcium carbonate powder for flue gas desulfurization (average particle size: 12 μm, Nittetsu Mining) as the experimental dust collection powder. In the dust collection load confirmation test, the pressure loss (kPa) and exhaust dust concentration (LD-3K2, Shibata Scientific) at the start and end of the test were evaluated.
As is clear from the table showing the results, in Example 3, it was possible to achieve a lower pressure loss while maintaining the collection performance of Example 1.

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 exit 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 material 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 volume 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 via 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 volume 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, blower or 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 method described above 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.

FIG. 11 shows a schematic diagram of a treatment box 200 for forming a dust-trapping 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, the same reference numbers are used in FIG. 11 as those 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 that of 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 blank 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 exterior 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 mounting flange 220 fluid-tight seal the processing volume 222 from the environment of the process box housing 214, and the mounting flange receiver 230 and filter element blank 206 fluid-tight seal the processing volume 222 from 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 only exit the processing volume 222 through the mounting flange outlet 238 after passing through the filter element wall 210 and reaching the space 234 formed between the exterior of the filter element blank 206 and the mounting flange receiver 230, 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 volume 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-shaped 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.
Referring to the above steps (i) to (iv) and the subsequent heating step, the dust trapping layer 202 is fixed to the filter element material 206 .

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, the same reference numbers are used in FIG. 13 as shown in FIG.
Unless otherwise noted, 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.
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 (ie, 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 that is 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 FIG. 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 the inside of the filter element 204 is exposed to the treatment space 222, similar to the treatment box 200 of FIG.
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 with respect to the embodiment of FIGS.
With reference to the above steps (i) to (v) and the subsequent heating step, the dust-collecting layer 202 is fixed to the filter element body 206 .

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 Figures 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-trapping layer 202 can be formed on the outer surface of the filter element material 206 to manufacture a filter element having the dust-trapping 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 a 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 of 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.

FIG. 15 shows different views of a further filter element material 206 on whose interior and/or exterior 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.

According to the procedure of 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 prepared filter element had a filtering surface of 0.15 ^m2 .
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 ^m2
Dust load: 1.5 kg clay slate, equivalent to a volume of 2.0 L Air flow: 107.1 m ³ /s (start of test) - 84 m ³ /s (end of test)
Dust mass flow rate: 60 g/s
Dust feed concentration: 2017.0 g/ ^m3
Pulse cleaning cycle: 28 seconds
Pulse cleaning 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/ ^m2
After 1 hour: 0.071 mg/ ^m2
After 43 hours: 0.099 mg/ ^m2
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.

10 Sinter lamellar dust collector
12 Casing
14 Top plate
16 Dust collection chamber
18 Clean Air Chamber
20 Dust-containing air supply port
22 Clean air outlet
24 Filter element
24a Hollow chamber
26 Hopper
28 Dust outlet
32 Large diameter part
34 Frame
36 Fastening bolt
38 Gasket
91 Aerosol outlet
92 Compressed air outlet
93 Dust collection layer constituent powder
100 Fans
101 Fixed quantity supply device
102 Upper tank
103 Upper clean air chamber
104 Dust transport 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 Inner 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 receiver
236 Second housing 238 Pump 300 Lamella structure
302 Spiral structure
304 Protrusion
306 Recess
308 Undercut part
310 Pocket-like or bag-like structure

Claims (19)

thoroughly mixing two or more types of microparticles;
forming a particulate layer of two or more types of particulates, the particulate layer not including a binder and/or a solvent, 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 . The method for manufacturing a filter element according to claim 1, wherein the particle size of one or more of the two or more types of particles is smaller than that of the resin that constitutes the filter element material. The method for manufacturing a filter element according to claim 1, wherein the fine particles are powder-like fine particles. The method for manufacturing a filter element according to claim 1, in which each of the two or more types of particulates is gradually layered on the surface of the filter element material to form a mixed particulate layer consisting of multiple particulate layers. 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. The method for manufacturing a filter element according to claim 1, wherein the two or more types of particulates are separately sucked into the filter element material, and the particulate layer is formed in a layer shape on the surface of the filter element material. 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. 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. 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. 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. 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. 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. The method of claim 10 , wherein the geometric configuration of the lamellar structure is a helical configuration. 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). The method for manufacturing a filter element (204) according to claim 1, wherein one of the two or more types of particulates constitutes a matrix material of the dust-collecting layer (202) and is made of the same resin material as the filter element material. The method for manufacturing a filter element (204) according to claim 14, wherein one of the two types of particulates constituting the matrix material of the dust-collecting layer (202) is polyethylene. 2. The method of claim 1, wherein the particulate material is a material selected from the group consisting of LDPE, HDPE, and PTFE. The method for manufacturing a filter element (204) according to claim 1, characterized in that the two or more types of particulates do not contain perfluoroalkoxyalkane (PFA). 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 .