Metal mesh coffee filter and method for forming a ceramic layer on the filter body of a metal mesh coffee filter

Abstract

To provide a metal mesh coffee filter and a method of forming a ceramic layer on a filter body of the metal mesh coffee filter that are related to forming of ceramic coating and solve the problems of clogging with coffee powder, intrusion of fine powder into extracted coffee liquid, and further a reduction in aromatic property of coffee liquid due to coffee oil components being adsorbed onto the filter.SOLUTION: A ceramic layer 2C is formed on surfaces of vertical line 21 and horizontal lines 22 forming a filter body 2. The ceramic layer 2C is made by first applying a coating 2P that forms a hydrophilic coating to front and back surfaces of the filter body 2 to form a hydrophilic film 2H on the vertical lines 21 and the horizontal lines 22, and then re-coating the hydrophilic film 2H with the coating 2P to spread the coating 2P over an entire area of the vertical lines 21 and the horizontal lines 22 through the hydrophilic film 2H.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a coffee filter for brewing coffee, and particularly to a metal mesh coffee filter that prevents leakage of fine powder of coffee powder while preventing clogging caused by the fine powder of coffee powder.

Background Art

[0002] When brewing coffee, paper filters are generally widely used. This product has been evaluated for its ease of use, but on the other hand, it has also been pointed out that the unique smell of paper transfers to the coffee, and the oil component in useful coffee is also adsorbed, reducing the umami components, flavor components, etc. of the extracted coffee liquid. For this reason, users who are more particular about the taste, aroma, etc. of coffee use metal mesh filters such as stainless steel mesh.

[0003] However, metal mesh filters, naturally, due to the relationship of the mesh opening dimensions, etc., fine powder of coffee powder is likely to leak, and the fine powder that cannot be completely leaked clogs at the wire crossing parts that make up the mesh, and if this grows, the filtering function will also be reduced.

[0004] For these reasons, the present inventor has already proposed Patent No. 6553546 "Metal Mesh Coffee Filter and Its Manufacturing Method" (Patent Document 1) and JP-A-2021-040964 "Filter for Extracting Extract and Its Manufacturing Method" (Patent Document 2), and disclosed a method for solving the above problems by devising the mesh shape and ceramic coating, and has been favorably received by users. However, even with such improvements, when using a natural raw material such as coffee powder, problems such as clogging by the coffee powder, problems such as fine powder mixing into the extracted coffee liquid, and further problems such as a decrease in the aroma of the coffee liquid due to the adsorption of the coffee oil component by the filter still cannot be completely eliminated.

Prior Art Documents

[0005] [Patent Document 1] Patent No. 6553546 [Patent Document 2] Japanese Patent Publication No. 2021-040964 [Overview of the project] [Problems that the invention aims to solve]

[0006] In view of these circumstances, the inventors have attempted to investigate the formation of ceramic coatings and have set forth the objective of developing a metal mesh coffee filter and a method for forming a ceramic layer on the filter body of a metal mesh coffee filter that can solve the above-mentioned problems. [Means for solving the problem]

[0007] First, the metal mesh coffee filter described in claim 1 is, A coffee filter comprising a filter body formed in the shape of a container that tapers at the bottom using a metal mesh, wherein an appropriate amount of coffee grounds is placed in a coffee grounds storage section formed inside the filter body, and coffee liquid is extracted; A ceramic layer is formed on the surface of the vertical and horizontal lines that form the filter body. This ceramic layer is a paint that forms a hydrophilic coating film. First, apply the coating to both the front and back surfaces of the filter body to form a hydrophilic film on the vertical and horizontal lines. Next, paint is applied to this hydrophilic film, allowing the paint to spread throughout the entire length and width of the vertical and horizontal lines through the hydrophilic film. the law of nature, Furthermore, the intersections and overlapping portions of the wires constituting the filter body are smoothed with a ceramic layer. Furthermore, the filter body is configured such that, with a ceramic layer formed on its surface and tilted at a set angle on the filter surface, the permeable particle size is smaller than the diameter of fine coffee grounds. It is characterized by the following:

[0008] Also, claims 2The metal mesh coffee filter described is as described in the claim 1st article In addition to the requirements listed, The aforementioned ceramic layer is characterized by having pores with a diameter of 0.1 to 3 μm.

[0009] Also, claims 3 The metal mesh coffee filter described is as described in the claim 1st article In addition to the requirements listed, The aforementioned coating is characterized by bonding with the material of the coated surface through ionic bonding.

[0010] Also, claims 4 The metal mesh coffee filter described is as described in the claim 1st article In addition to the requirements listed, The aforementioned metal mesh is twill Ori It is formed by be It is characterized by the following:

[0011] Also, claims 5 The metal mesh coffee filter described is as described in the claim 1st article In addition to the requirements listed, The aforementioned ceramic layer is characterized by having a thickness of 4-8% of the diameter of the wire that performs the filtering action.

[0012] Also, claims 6 The description 、 A method for forming a ceramic layer on the filter body of a metal mesh coffee filter is: A method for forming a ceramic layer on a filter body in a coffee filter, which comprises a filter body formed in the shape of a container that tapers at the bottom using a metal mesh, and in which an appropriate amount of coffee grounds is placed in a coffee grounds-containing section formed inside the filter body for extracting coffee liquid, With respect to the vertical and horizontal lines forming the filter body, First, a paint that forms a hydrophilic coating is applied to form a hydrophilic film on the vertical and horizontal lines. Next, by applying paint repeatedly on this hydrophilic film, the paint is made to spread over the entire area of the vertical and horizontal lines through the hydrophilic film. It is, Furthermore, the intersections and overlapping portions of the wires constituting the filter body are smoothed with a ceramic layer. Furthermore, the filter body is configured such that, with a ceramic layer formed on its surface and tilted at a set angle on the filter surface, the permeable particle size is smaller than the diameter of the fine coffee grounds. It is characterized by this.

[0013] Also, the claim 7 described 、 The method for forming a ceramic layer on the filter body in a metal mesh coffee filter is, in addition to the requirements described in the above claim 6 described, The ceramic layer is characterized in that pores with a diameter of 0.1 to 3 μm are formed.

[0014] Also, the claim 8 described 、 The method for forming a ceramic layer on the filter body in a metal mesh coffee filter is, in addition to the requirements described in the above claim 6 described, The paint is characterized in that it binds to the material of the coating surface by ionic bonding.

[0015] Also, the claim 9 described 、 The method for forming a ceramic layer on the filter body in a metal mesh coffee filter is, in addition to the requirements described in the above claim 6 described, The metal mesh is formed in a twill weave be and is characterized by this.

[0016] Also, the claim 10 described 、 The method for forming a ceramic layer on the filter body in a metal mesh coffee filter is, in addition to the requirements described in the above claim 6 described, The thickness of the ceramic layer is characterized in that it is 4 to 8% of the diameter of the wire responsible for the filtering action. The aforementioned problems are then solved by means of the configuration of the invention described in each of these claims. [Effects of the Invention]

[0017] First, claim 1 and 6 According to the invention described, due to the hydrophilicity of the hydrophilic film formed on the vertical and horizontal lines, the paint applied over this hydrophilic film instantly penetrates and spreads throughout the entire hydrophilic film, thereby increasing the layer thickness. Furthermore, in areas where there are uneven or missed areas in the paint application, the applied paint expands the hydrophilic film, eliminating these issues. As a result, a ceramic layer can be formed in which the paint has spread throughout the entire vertical and horizontal lines. Furthermore, since the vertical and horizontal lines are entirely embedded in the ceramic layer and not exposed, it is possible to prevent coffee grounds from getting caught in the wire material. Furthermore, according to the present invention, the wire can be reliably embedded in the ceramic layer, especially at intersections and overlapping sections where coffee fine powder is prone to getting trapped. This makes it possible to more reliably avoid trapping coffee fine powder by the wire.

[0018] Also, claims 2 and 7 According to the described invention, since fine coffee grounds are not trapped in the pores, the ceramic layer can be kept clean.

[0019] Also, claims 3 and 8 According to the described invention, the ceramic layer can be made to have excellent strength and can be formed to be extremely thin.

[0020] Also, claims 4 and 9 According to the described invention, it is possible to exert the effect of the ceramic layer without impairing the high filtration accuracy of the twill weave wire mesh.

[0021] Also, claims 5 and 10 According to the described invention, it is possible to prevent a decrease in filtration function due to the formation of a ceramic layer. [Brief explanation of the drawing]

[0022] [Figure 1]This is a perspective view (a) showing an example of use of the filter (metal mesh coffee filter) of the present invention, and a perspective view (b) showing the filter in a disassembled state, excluding the upper support material. [Figure 2] These are front cross-sectional views, plan views, and bottom views of the filter, viewed from three different directions. [Figure 3] This is an explanatory diagram showing a front cross-sectional view and a left side view of the filter, as well as an enlarged view of the bottom of the front cross-sectional view. [Figure 4] This diagram (a) shows the planar unfolded shape of the flat mesh that forms the initial shape of the filter body, and how it is folded to form a three-dimensional filter body that tapers downwards, as well as a projection view (b) showing the joint of the flat mesh as seen from the direction of arrow A in the partial diagram. [Figure 5] This is an explanatory diagram illustrating, step by step, the process of forming a flat mesh with a clamping surface into a three-dimensional structure on a filter body that tapers downwards. [Figure 6] These are a front view and a vertical cross-sectional view showing, step by step, how the ceramic layer is formed on the filter body of the metal mesh coffee filter of the present invention. [Modes for carrying out the invention]

[0023] The embodiments for carrying out the present invention include those described in the following examples, as well as various forms and methods that can be further improved within the technical concept. In this explanation, we will first describe the metal mesh coffee filter 1, and then describe the manufacturing method of this filter. [Examples]

[0024] The metal mesh coffee filter 1 for extract extraction of the present invention (hereinafter sometimes simply referred to as filter 1) comprises a filter body 2 formed in the shape of a container that tapers to the bottom using a metal mesh. After placing extraction raw materials P, such as coffee grounds, inside the filter, hot water is poured from above to extract the extract components (e.g., coffee oil, coffee aroma, etc.) from the extraction raw materials P. For this reason, filter 1 of the present invention is mainly suitable for extracting coffee liquid, but it can also be applied to simple extraction methods to extract umami components (extract components) from other raw materials P, such as bonito flakes, kelp, and shiitake mushrooms, by pouring hot water over them (so-called dashi). Incidentally, while dashi is traditionally made by boiling raw materials such as bonito flakes, this specification also includes simple methods of making dashi, namely, pouring hot water over bonito flakes, etc., which are the extraction raw materials P, as part of the extraction process. However, the following explanation is primarily based on the premise of coffee extraction, in which case the extraction raw material P will be coffee grounds of an appropriate particle size, such as fine, medium, or coarse.

[0025] The filter 1 of the present invention mainly consists of a filter body 2 formed in the shape of a container that tapers downwards using a metal mesh, as described above. As an example, as shown in Figures 1 to 3, this filter body 2 is formed in a sloping shape that is open at the top and tapers downwards, similar to a typical commercially available paper filter, and this sloping surface mainly constitutes the filter surface (filtration surface). Naturally, during extraction, an appropriate amount of extraction raw material P, such as coffee grounds, is put into the inner space of this filter body 2, and this space is called the raw material storage section R.

[0026] The filter body 2 is formed from a metal mesh (SUS) as described above, and in this embodiment, the metal mesh is, for example, a twill weave. Orikin A net will be used. This twill mat Ori The wire mesh is a combination of a flat weave and a twill weave pattern, in which the horizontal wires 22 are woven across every two vertical wires 21, resulting in a double layer of horizontal wires and a structure that is tightly attached on both the front and back sides. OrikinThe mesh is woven in a way that leaves no gaps, and a winding flow path is formed in the depth direction of the wire mesh. The aforementioned woven mat Orikin An example of the net's specifications is shown below. Vertical wire diameter 50 μm, vertical mesh 165, horizontal wire diameter 50 μm, horizontal mesh 600 (the mesh of twill weave wire mesh is expressed by the number of horizontal wires between 25.4 mm (1 inch) of openings), mesh opening 100 μm, particle size passing through 15 μm or less. In this embodiment, the diameter of the vertical line 21 and the diameter of the horizontal line 22 are the same, but the diameter of the vertical line 21 may be made larger than the diameter of the horizontal line 22. In this embodiment, as a metal mesh, one example is a twill weave. Orikin While a mesh was used, various types of wire mesh woven with other methods, such as plain weave wire mesh, can also be used.

[0027] This type of twill weave Orikin The filter body 2, which is constructed using a mesh, has a filter surface with an inclination angle of approximately 55°, as shown in the front cross-sectional view of Figure 2. In this inclined state, and with the ceramic layer 2C formed on its surface as described later, the permeable particle size is set to be smaller than that of fine coffee grounds (for example, approximately 20 μm) (1 to 9 μm (or 9 μm or less)).

[0028] Such settings are made considering the gap dimensions between the horizontal lines 22 (projection distance viewed from the vertical direction) as well as the thickness of the ceramic layer 2C. In the filter 1 of the present invention, the horizontal lines 22 are mainly configured to prevent the passage of fine coffee grounds. In other words, the coffee grounds are roasted and have a porous structure, and the surface of these fine particles is not smooth but has protrusions of various sizes. Furthermore, since the extracted liquid flows down the inclined surface (55°) of the filter body 2, much of the fine powder gets caught on the horizontal line 22. On the other hand, the gap between the vertical lines 21 is larger than the size of fine coffee grounds (approximately 20 μm), thereby improving the passability of the extracted coffee liquid and preventing the extraction time from becoming excessively long.

[0029] Please note that the mesh sizes (mesh spacing) mentioned above are merely examples; horizontal mesh spacing can be applied up to approximately 500-650 mesh spacing, and vertical mesh spacing can be applied up to approximately 100-250 mesh spacing.

[0030] Furthermore, the filter body 2 is initially formed in a planar unfolded state, as shown in Figure 4(a) as an example, and this is referred to as a flat mesh W0 in this specification. This flat mesh W0 is then folded as appropriate to form a three-dimensional, tapered filter body 2. The planar unfolded flat mesh W0 can be obtained, for example, by punching it out from a metal mesh sheet (so-called blank punching). The planar unfolded shape of the flat mesh W0 is as shown in Figures 4(a) and 5 above, and consists of two approximately isosceles trapezoids placed side by side. These approximately isosceles trapezoids are folded opposite each other so that the central bottom 2B (the bottom 2B of the filter body 2 when formed in a three-dimensional state) is symmetrical (a line). At this time, the clamping allowances Wa formed on the edges (joint WJ) of the opposing approximately isosceles trapezoids are joined together in an overlapping manner to form a three-dimensional, tapered filter body 2. Therefore, the filter body 2 is provided with support members 3 that serve as reinforcing frames at the joint WJ, bottom 2B, or upper opening during three-dimensional formation, thereby maintaining the three-dimensional shape of the filter body 2.

[0031] The following describes the support material 3. As shown in Figures 1(b) and 2 as an example, the support member 3 is basically a support member (reinforcement frame material) that clamps the filter body 2 from both the inside (raw material containment section R side) and the outside with an appropriate width dimension. In particular, at the joint WJ of the three-dimensional filter body 2, the clamping portions Wa formed therein are overlapped, and the joint WJ is held with an appropriate width dimension. Then, in this clamped state, the support member 3 and the metal mesh (overlapping portion) are joined together by, for example, spot welding, and integrated. With such a support member 3, the thin mesh filter body 2 is reliably formed into a three-dimensional state, and that three-dimensional state is maintained for many years. In this invention, the filter body 2 is basically formed in a three-dimensional state with a flat lower tip (including a line segment), as shown in Figure 1, and this is sometimes referred to as a roughly frustoconical shape (three-dimensional trapezoidal shape) (see Figure 4(a)). Alternatively, the filter body 2 may also be formed in a three-dimensional state with a pointed lower tip, and this may be referred to as a cone shape.

[0032] Due to this configuration, the support member 3 comprises, as an example, an inner support member 31 provided inside the three-dimensionally formed filter body 2, an outer support member 32 provided outside the three-dimensionally formed filter body 2, and an upper support member 33 provided at the upper opening (upper open portion) of the three-dimensionally formed filter body 2, as shown in Figure 1 above. The following describes each component that makes up the support material 3.

[0033] First, the inner support member 31 is formed in a roughly U-shape with the U-shaped opening facing upwards, or in a roughly V-shape with a flat bottom, as shown in Figure 1(b) above as an example, and is continuously bent from one joint side (joint WJ) of the filter body 2, through the bottom 2B, to the other joint side (joint WJ). In other words, the inner support member 31 is bent to continuously connect the bottom 2B of the filter body 2, which is tapered at the bottom in its three-dimensional state, and two opposing lines (two joint lines (joint WJ)) on the side circumferential surface located on its extension, and plays the role of firmly supporting (pressing down) the joint WJ of the filter body 2 in particular. Therefore, the inner support member 31 comprises a bottom inner support member 31B that supports the bottom 2B of the filter body 2, and a side inner support member 31S that supports the joint WJ (side) of the filter body 2. Overall, the bottom inner support member 31B is formed in a long, narrow, flat shape, while the long, narrow side inner support member 31S is formed by bending it in an inclined shape. The bottom inner support member 31B is formed in a nearly flat shape that does not curve in the width direction, but the side inner support member 31S is preferably formed to be slightly curved in the width direction (short side direction), because it is desirable for it to substantially follow the side surface (curved surface) of the filter body 2.

[0034] Furthermore, a filtration-promoting opening 34 is provided in the bottom inner support material 31B, and the metal mesh that constitutes the filter body 2 is stretched over this filtration-promoting opening 34. In this way, the bottom inner support material 31B, which supports and reinforces the bottom 2B of the filter body 2, is also configured to have a filtration function. Thus, a filtration-promoting opening 34 is formed in the bottom inner support material 31B to improve and promote the filtration process, preventing over-extraction of extracts that would occur if the bottom of the filter were formed to be blocked, and preventing impurities from being mixed into the extract (coffee liquid). For this reason, in this specification, the opening formed in the bottom 2B (bottom inner support material 31B) of the filter body 2 is referred to as a filtration-promoting opening 34.

[0035] Furthermore, since the filter body 2 is stretched across the bottom 2B (bottom inner support material 31B), it is preferable that the filtration-promoting opening 34 be opened to the largest possible size. In other words, since the idea is that the fine particles of coffee grounds (extraction raw material P) are captured by the filter body 2 at the bottom 2B, the filtration-promoting opening 34 itself can be opened to a large size without considering the passage or non-passage of fine particles. In other words, from the perspective of improving the permeability of the extracted liquid (coffee liquid), it is desirable that the filtration-promoting opening 34 be opened to the largest possible size, as long as it does not impair the strength of the bottom inner support material 31B. At least in the case of coffee extraction, the filtration-promoting opening 34 should be formed to a size larger than the particle size of coarsely ground coffee grounds (for example, a particle diameter of about 0.72 to 0.92 mm). Furthermore, during extraction, as shown in the enlarged section of Figure 3 as an example, the extraction material P (fine coffee grounds and coffee residue) captured by the filter body 2 is stored in the filtration-promoting opening 34. However, by making the filtration-promoting opening 34 larger, the captured and stored extraction material P (coffee residue) does not clog the filtration-promoting opening 34 (it does not form bridges), and after extraction, it can be easily removed from the filtration-promoting opening 34 simply by rinsing it with water from both the inside and outside.

[0036] To give a more specific explanation of the size of the filtration-promoting opening 34, when the width dimension of the bottom inner support material 31B is approximately 8 mm and the length dimension is approximately 39 mm, the filtration-promoting opening 34 is formed as an oval-shaped opening, for example, as shown in Figures 1 and 2, and its dimensions are, for example, approximately 6 mm in the short axis direction and approximately 35 mm in the long axis direction.

[0037] Next, the outer support member 32 will be described. The outer support member 32 is a component that is paired with the inner support member 31 (particularly the side inner support member 31S) described above, and is provided to sandwich the filter body 2. In other words, the outer support member 32 is responsible for supporting the filter body 2 from the outside (outside the raw material storage section R). However, in this configuration, the outer support member 32 is not present near the center of the bottom of the filter body 2 where the filtration-promoting opening 34 is formed, in order to allow filtration by the filter body 2 (the filter body 2 stretched over the filtration-promoting opening 34) to proceed smoothly. Therefore, the outer support member 32 is configured to be substantially divided by a pair of left and right side outer support members 32S, as shown in Figure 1(b) above, for example, but the bottom 2B of the filter body 2 is supported by a covering cap 35, which will be described later. Incidentally, the gap below the outer support members 32 (side outer support members 32S) that are provided in a divided state on the left and right is broadly included in the filtration promotion opening 34. Furthermore, since the entire filter body 2 (filter surface) is formed in a sloping shape that tapers downwards, it is preferable that the outer support member 32 be formed to be somewhat wider than the inner support member 31, in order to firmly grip the filter body 2. Furthermore, the outer support member 32 (side outer support member 32S) is formed in almost the same inclination as the side inner support member 31S.

[0038] Next, we will describe the covering cap 35 that supports the bottom 2B of the filter body 2. As an example, the covering cap 35 is attached to the bottom 2B of the filter body 2, or more specifically, to the corners at both ends of the bottom 2B, from below, by welding or the like, as shown in Figure 1(b). Furthermore, when attaching the covering cap 35, as an example, as shown in the enlarged view of Figure 3, it is attached so that its upper end abuts against the lower end of the outer support member 32. Furthermore, as shown in Figure 1(b) above, the covering cap 35 has vertical walls 35W formed on both sides, and the bottom 2B (four corners) of the filter body 2 is attached so as to be contained (covered) inside these vertical walls 35W. Furthermore, the filter body 2 is formed by folding two roughly isosceles trapezoidal shapes made of metal mesh from both sides at the bottom 2B of the filter body 2. During this folding, pinholes sometimes occurred at the four corners at both ends of the bottom 2B. However, even if pinholes occur, they are reliably covered by the covering cap 35, resulting in a structure that prevents almost all fine coffee grounds from passing through the pinholes (and mixing them into the extracted coffee liquid).

[0039] Next, the upper support member 33 will be described. The upper support member 33 is a frame member (reinforcement frame member) for supporting the upper opening (upper open portion) of the filter body 2, which is formed in three dimensions as described above. This upper support member 33 is also provided so as to clamp the opening edge of the filter body 2 from both the inside and the outside around its entire circumference. The upper support member 33 and the metal mesh (filter body 2) are then welded (for example, spot welded) at this clamping portion to form a single unit. When distinguishing between the inner and outer upper support members 33, they are referred to as the inner upper support member 33I and the outer upper support member 33U. Incidentally, the inner upper support member 33I is formed by bending it (in a flange-like shape) so that it protrudes from the top surface to the outer circumference, as shown in the enlarged section of Figure 2, for example, and a part of it further protrudes outwards to form the handle 36 of the filter 1. Furthermore, as shown in Figure 2 (partially in the enlarged view), the upper support member 33 is preferably provided so as to abut the upper ends of the inner support member 31 and the outer support member 32 described above. This integrates the support member 3 as a whole, achieving overall shape maintenance and increased strength of the three-dimensionally formed filter body 2.

[0040] Furthermore, in forming the filter body 2 in three dimensions from the flat mesh W0, as described above, the approximately isosceles trapezoidal joints WJ are overlapped as shown in Figure 4(b) as an example, and this overlapping portion is referred to as the clamping allowance Wa. Furthermore, before supporting with the support material 3, the clamping allowance Wa of the flat metal mesh W0 is overlapped in advance and spot-welded. This makes it easier to subsequently clamp and join with the inner support material 31 and the outer support material 32. Incidentally, in the planar unfolded shape of the flat mesh W0, as shown in Figures 4(a) and 5 as an example, a clamping allowance Wa, which becomes a folded piece, is formed in the longitudinal (folded line) direction extension of the bottom 2B, for example, with a length of about 10 mm. Then, in forming this flat mesh W0 into a three-dimensional shape, first, the clamping portions Wa formed at the roughly isosceles trapezoidal joint WJ are folded so that they overlap, and then the folded pieces (clamping portions Wa) are folded again from the outside of the overlapping joint WJ so that they overlap (see Figure 5). As a result, the extensions at both ends of the bottom 2B are formed by overlapping a total of three clamping portions Wa (mesh fabric) (see "triple" in Figures 4 and 5), and the other joints WJ are formed by overlapping a total of two clamping portions Wa (mesh fabric). Of course, by overlapping the clamping portions Wa in this way, the thickness dimension increases accordingly, but since it is sandwiched between the inner support material 31 and the outer support material 32, which are approximately 1 mm thick, there is no adverse effect. Furthermore, as will be explained in more detail later, after forming the filter body 2 by creating a three-dimensional shape from the flat mesh W0, a ceramic baking coating is applied to both the front and back surfaces of the filter. As a result, minute gaps can be filled by the flow of this coating.

[0041] As an example, filter 1 is constructed by providing a cup rest 4 at the bottom of the filter body 2, as shown by dashed lines (double-dotted lines) in Figures 1(a) and 3, thereby allowing the filter body 2 to be held above the cup C. The cup holder 4 comprises a hollow disc 41 that is placed on the opening edge of a cup C (including a server, etc.) that stores an extracted liquid such as coffee, and a tapered folded portion 42 is continuously formed in the approximate center of the disc. This folded portion 42 is fixed to the outer support member 32 of the filter body 2 by welding or the like, thereby integrating it with the filter body 2 (integration of the filter body 2 and the cup holder 4). For this reason, the angle of the tapering (angle of inclination) of the folded portion 42 is approximately the same as the angle of the outer support member 32. Incidentally, although the cup holder 4 is described here as being fixed to the filter body 2, the cup holder 4 can also be attached to the filter body 2 in a detachable manner.

[0042] A characteristic feature of the present invention is that the filter body 2 is coated with a ceramic material on both its front and back surfaces, forming a ceramic layer 2C. The formation of this ceramic layer 2C is a coating treatment that enhances hydrophilicity. After the coffee has been extracted, simply rinse off any coffee grounds adhering to the filter body 2 with running water, then lightly scrub with a sponge, or soak the filter body 2 in water and then lightly scrub with a sponge under running water. This allows water to penetrate between the ceramic layer 2C coating and the dirt, lifting the dirt and making it easier to remove.

[0043] Furthermore, as an example, the paint 2P used to form the ceramic layer 2C is Velascoat manufactured by Shinkosha Co., Ltd. This material bonds to the coated surface material (SUS) through ionic bonding, exhibiting a much stronger bonding force compared to conventional paints that bond to the coated surface material through van der Waas forces. Incidentally, using a coating that matches the thermal expansion coefficient of the metal being coated will reduce the occurrence of delamination and cracking. Furthermore, in this embodiment, as will be described later, the thickness of the ceramic layer 2C is set to 2-4 μm, so the particle size of silica, which is the main component of the paint 2P, is optimized. The paint 2P is milled to adjust the particle size to 300-500 nm (7.5-25% of the thickness of the ceramic layer 2C).

[0044] Furthermore, the ceramic layer 2C formed by the aforementioned paint 2P has countless pores, the diameter of which is 0.1 to 3 μm. By setting the pore diameter to the above-mentioned dimensions, clogging of the pores with fine coffee grounds (20 μm) can be avoided. Furthermore, coffee oils do not penetrate these pores due to the surface tension of the oil. In addition, since the ceramic layer 2C is hydrophilic, the coffee oil components are repelled by the ceramic layer 2C and pass through the filter body 2 along with the coffee extract.

[0045] While such ceramic layers 2C have been disclosed in the prior art described above, the present invention has, through much trial and error, discovered a nearly optimal configuration for their formation. In other words, the ceramic layer 2C needs to be formed to a certain thickness in order to fully exhibit its water affinity. On the other hand, since such measures effectively narrow the mesh spacing (mesh opening), finding the optimal thickness for the ceramic layer 2C was not always easy. Furthermore, coffee grounds are a natural material, and depending on how the coffee beans are ground, they can be coarse, medium, or fine. Even if there is an average particle size, these particle sizes are not uniform, making the generation of finely ground coffee grounds unavoidable. This invention investigates the optimal thickness of the ceramic layer 2C, taking these conditions into consideration. In conclusion, the thickness of the ceramic layer 2C is 2 to 4 μm (4 to 8% of the diameter of the transverse wire 22 that performs the filtering action). The reason why the ceramic layer 2C can be made into such an extremely thin film is, as mentioned above, because the paint 2P is strongly bonded to the material (SUS) of the coated surface by ionic bonds.

[0046] Furthermore, according to the present invention, the ceramic layer 2C, which is set to such a thickness, can be formed not only on the surface of the wire portion (vertical wires 21, horizontal wires 22) of the filter body 2, as will be described in detail later, but also in areas where it is important to reliably form the ceramic layer 2C, such as the intersections 2X and overlapping portions 2W of the wires, that is, in areas where there is a risk of fine coffee grounds getting stuck. The wire intersection 2X is the point where the vertical wire 21 and the horizontal wire 22 intersect, while the overlapping point 2W is the point where adjacent wires come into contact. Both of these points are areas where fine coffee grounds may get trapped. Furthermore, the overlapping section 2W includes not only the overlapping of wires themselves, but also the parts where the wires and the support material 3 overlap.

[0047] Incidentally, in conventional methods for forming ceramic layers 2C with such thickness dimensions, surface tension sometimes prevented the paint 2P from spreading evenly across the entire surface of the fine wire, resulting in insufficient coating of paint 2P at wire intersections 2X, overlapping sections 2W, etc. Furthermore, applying additional paint 2P to these uncoated areas would thicken the ceramic layer 2C, inevitably resulting in a smaller mesh opening. On the other hand, according to the present invention, it is possible to secure the desired mesh opening dimensions without leaving any areas uncoated with paint 2P.

[0048] The metal mesh coffee filter 1 of the present invention has the basic structure described above, and the manufacturing method of such a filter 1 will be described below. (1) Planar unfolded shape of flat mesh As described above, the filter body 2 is formed three-dimensionally from a flat mesh W0 that is in a planar unfolded state. As an example of its planar unfolded shape, as shown in Figure 4(a), it is formed by arranging two approximately isosceles trapezoids symmetrically on the left and right sides, with the lower end of the filter body 2 (the bottom 2B when formed three-dimensionally) being symmetrical. When forming the three-dimensional structure, the two approximately isosceles trapezoids are folded at the symmetrical bottom 2B, and the edges of the two approximately isosceles trapezoids are joined together to form the three-dimensional structure (the edges of the approximately isosceles trapezoids that are joined together are the joint WJ). To describe the shape of the flat mesh W0 in more detail, first, the joint WJ is provided with a clamping allowance Wa for overlapping each other. Furthermore, a clamping allowance Wa is provided in the longitudinal (folded line) direction extension of the bottom 2B during three-dimensional formation. This is a folded piece that extends, for example, about 10 mm from the end of the bottom 2B. Here, the symbol "WB" in the figure represents the bottom fold line for folding the two roughly isosceles trapezoidal shapes relative to the bottom 2B, and in this case, two parallel lines are formed. The symbol "WS" in the figure represents the side fold line for folding the clamping allowance Wa formed at the joint WJ.

[0049] To obtain a flat mesh W0 of this shape, as described above, it can be obtained, for example, by punching out a flat mesh W0 of the above shape from a long mesh sheet (blank punching). Furthermore, by setting the longitudinal dimension of the bottom 2B in Figure 4(a) to be shorter, it is possible to obtain a filter 1 that is more or less conical than roughly frustoconical (three-dimensional trapezoidal) as a three-dimensional filter body 2, which is intended for a filter body 2 that corresponds to a conventional conical dripper.

[0050] (2) Bending of flat mesh Subsequently, the flat mesh W0 described above is formed into a three-dimensional shape on the filter body 2, which is tapered at the bottom. As shown in Figures 4(a) and 5, the clamping pieces Wa formed at the roughly isosceles trapezoidal joint WJ are first folded so that they overlap. Then, the clamping pieces Wa, which are folded pieces formed as extensions of both ends of the bottom 2B, are folded to overlap the overlapping joint WJ. As a result, the extensions of both ends of the bottom 2B are formed by the overlapping of a total of three clamping pieces Wa (mesh fabric), and the other joint WJ is formed by the overlapping of a total of two clamping pieces Wa (mesh fabric). In this embodiment, at the extensions at both ends of the bottom 2B, the clamping portions Wa, which are folded pieces formed in those areas, are folded and overlapped so that they are located on the outermost part of the filter body 2. Here, the mesh fabric (metal mesh) forming the clamping portions Wa, although thin, has thickness, so at the extensions at both ends of the bottom where three layers are stacked, the clamping portions Wa may not overlap precisely and may protrude slightly from the corners. However, in this embodiment, since the covering caps 35 are fitted to both ends of the bottom 2B from the lower outside, even if the clamping portions Wa protrude from the corners, they will be contained within (covered) the vertical wall portion 35W of the covering caps 35, and exposure to the outside will be prevented.

[0051] (3) Spot welding (temporary welding) Subsequently, with the clamping portions Wa overlapping as described above, the clamping portions Wa of the flat mesh W0 are spot-welded (pre-welded) prior to clamping with the support material 3. By performing the spot welding first, the subsequent clamping and joining with the support material 3 becomes easier. When performing spot welding, for example, in a flat mesh W0, two sides of a roughly isosceles trapezoid (the clamping allowance Wa of the joint WJ) facing each other are overlapped on top of an appropriate receiving jig, and then this overlapping portion (clamping allowance Wa) is spot-welded.

[0052] (4) Clamping by inner support material and outer support material Subsequently, the flat mesh W0 (filter body 2) is sandwiched from the inside and outside by the support members 3 (inner support member 31 and outer support member 32), and in this sandwiched state, the support members 3 and the filter body 2 (metal mesh) are joined by welding (for example, spot welding) (see enlarged view of Figure 4(a)). Of course, after the outer support member 32 is attached, the covering cap 35 is joined so as to abut its lower end. When joining the support material 3 and the filter body 2, the spacing of the spot welds may be equal above and below the joint WJ (clamping allowance Wa), but since the filtration action of the filter surface is mainly on the lower side (approximately the lower half), it is preferable to make the welding spacing smaller towards the bottom. Furthermore, of the support members 3, the inner support member 31 in particular is arranged such that, when viewed from above, the bottom inner support member 31B that supports the bottom 2B and the side inner support members 31S that support the joints WJ on both sides are in a straight line, thereby strengthening the filter body 2.

[0053] (5) Installation of upper support members Furthermore, as described above, an upper support member 33 is attached around the entire circumference of the upper opening of the filter body 2, which is formed in three dimensions in this manner (see Figure 2). Specifically, an inner upper support member 33I and an outer upper support member 33U are attached so as to sandwich the upper opening edge of the filter body 2 from the inside and outside. These upper support members 33 are provided so as to abut the upper ends of the inner support member 31 and the outer support member 32, as described above (see a partially enlarged view of Figure 2).

[0054] (6) Formation of the ceramic layer Subsequently, a ceramic baked coating is applied to all parts of the front and back surfaces of the filter body 2 to form a ceramic layer 2C, and this method will be explained below.

[0055] i) Primer First, as shown in Figures 6(a) and (b), paint 2P is applied (spray-coated) to both sides of the filter body 2 to form a hydrophilic film 2H on the vertical lines 21 and horizontal lines 22 with a film thickness of 0.5 to 1.0 μm. In this example, the film thickness was set to 1.0 μm. The thickness of the hydrophilic film 2H is set to a value smaller than the thickness of the ceramic layer 2C, which is 4-8% (2-4 μm in this embodiment) of the diameter of the wire (horizontal wire 22) that performs the filtering action. This makes it possible to apply the paint 2P in multiple layers.

[0056] ii) Apply multiple coats Next, as shown in Figure 6(c), paint 2P is applied to the hydrophilic film 2H. The applied paint 2P instantly penetrates and spreads throughout the entire hydrophilic film 2H, wetting it. Furthermore, in areas where there are uneven areas or missed spots in the paint 2P application, the applied paint 2P expands the hydrophilic film 2H, eliminating these imperfections. As a result, the paint 2P spreads throughout the entire vertical line 21 and horizontal line 22. This process of applying multiple coats of paint 2P can be carried out until the paint 2P covers the entire area of ​​the vertical lines 21 and horizontal lines 22, but the thickness of the resulting ceramic layer 2C should not exceed 4-8% of the diameter of the horizontal line 22 (in this embodiment, the diameter of the horizontal line 22 is 50 μm, so this would be 2-4 μm).

[0057] In addition, at the intersection 2X, the paint 2P applied to the vertical line 21 and the paint 2P applied to the horizontal line 22, due to the surface tension acting on each, form an arc-shaped portion 2L, resulting in a so-called smoothed corner. As a result, the paint 2P can sufficiently fill the minute gaps that occur at the intersection 2X. Similarly, the minute gaps that occur at the overlapping portion 2W are also filled by the paint 2P. Furthermore, when applying the second coat of paint 2P, it should be done before the lower layer of paint 2P dries out completely.

[0058] iii) Baking As described above, once the multiple coats have been applied, a baking process is then carried out. The filter body 2 coated with paint 2P is placed in a heating furnace and, for example, heated at 300°C for approximately 60 to 90 minutes (the moisture is evaporated first, the temperature is gradually increased after evaporation, and the temperature is gradually decreased after the ceramics have set). The paint 2P that has undergone this heat treatment hardens, and the ceramic layer 2C is baked onto the filter body 2.

[0059] (7) Installation of cup holder Next, the cup holder 4 is assembled to the filter body 2, and the folded portion 42 of the cup holder 4 is fixed to the outer support member 32 of the filter body 2 by welding or the like.

[0060] The metal mesh coffee filter 1 of the present invention is manufactured as described above as an example. In the filter 1 manufactured in this manner, the diameter of the pores formed in the ceramic layer 2C is 0.1 to 3 μm, so fine coffee grounds (approximately 20 μm) are not trapped in these pores. Even if the filter body 2 becomes dirty, the hydrophilicity of the ceramic layer 2C allows water to penetrate below the dirt during washing, lifting it away. As a result, it can be easily cleaned with just water, making daily hygiene management easy for anyone. Furthermore, due to the surface tension of the oil, the coffee oil does not penetrate into the pores of the ceramic layer 2C. Moreover, because the ceramic layer 2C is hydrophilic, the coffee oil is repelled by the ceramic layer 2C and passes through the filter body 2 along with the coffee extract, resulting in a coffee extract that retains the original aroma of the coffee.

[0061] As mentioned above, the extensions at both ends of the bottom portion 2B are formed by overlapping a total of three clamping layers Wa (mesh fabric), which increases the thickness of that portion. However, since the ceramic layer 2C is formed on both the front and back surfaces of the filter body 2 after three-dimensional formation, minute gaps are not only filled by the flow of paint 2P, but according to the specifications disclosed in this invention, a smoothed state is achieved in which an arc-shaped portion 2L is formed, and this configuration prevents clogging by fine coffee grounds. [Explanation of symbols]

[0062] 1. Metal mesh coffee filter (filter) 2. Filter body 3 Support material 4 cup holders 21 Vertical lines 22 horizontal lines 2B Bottom 2C ceramic layer 2H Hydrophilic membrane 2X intersection 2P paint 2L arc section 2W overlapping section 31 Inner support material 31B Bottom inner support 31S Side inner support material 32 Outer support material 32S Side outer support 33 Upper support material 33I Inner upper support 33U outer upper support 34 Filtration promotion opening 35 Covering cap 35W vertical wall section 36 Handle 41 Hollow disk 42 Folded section W0 Flat Mesh WJ joint WB bottom broken line WS side break line Wa clamping allowance C cup P extraction raw material R Raw material storage section

Claims

1. A coffee filter comprising a filter body formed in the shape of a container that tapers at the bottom using a metal mesh, wherein an appropriate amount of coffee grounds is placed in a coffee grounds storage section formed inside the filter body, and coffee liquid is extracted; A ceramic layer is formed on the surface of the vertical and horizontal lines that form the filter body. This ceramic layer is a paint that forms a hydrophilic coating film. First, apply the coating to both the front and back surfaces of the filter body to form a hydrophilic film on the vertical and horizontal lines. Next, paint is applied to this hydrophilic film, allowing the paint to spread throughout the entire area of ​​the vertical and horizontal lines through the hydrophilic film. Furthermore, the intersections and overlapping portions of the wires constituting the filter body are smoothed with a ceramic layer. Furthermore, the metal mesh coffee filter is characterized in that the filter body has a ceramic layer formed on its surface, and the size of the permeable particles when tilted at a set angle on the filter surface is smaller than the diameter of the fine coffee grounds.

2. The metal mesh coffee filter according to claim 1, characterized in that the ceramic layer has pores with a diameter of 0.1 to 3 μm.

3. The metal mesh coffee filter according to claim 1, characterized in that the paint bonds to the material of the coated surface by ionic bonding.

4. The metal mesh coffee filter according to claim 1, characterized in that the metal mesh is formed in a twill weave.

5. The metal mesh coffee filter according to claim 1, characterized in that the thickness of the ceramic layer is 4 to 8% of the diameter of the wire that performs the filtering action.

6. A method for forming a ceramic layer on a filter body in a coffee filter, which comprises a filter body formed in the shape of a container that tapers at the bottom using a metal mesh, and in which an appropriate amount of coffee grounds is placed in a coffee grounds-containing section formed inside the filter body for extracting coffee liquid, With respect to the vertical and horizontal lines forming the filter body, First, a paint that forms a hydrophilic coating is applied to form a hydrophilic film on the vertical and horizontal lines. Next, paint is applied to this hydrophilic film, allowing the paint to spread throughout the entire area of ​​the vertical and horizontal lines through the hydrophilic film. Furthermore, the intersections and overlapping portions of the wires constituting the filter body are smoothed with a ceramic layer. Furthermore, the method for forming a ceramic layer on the filter body of a metal mesh coffee filter is characterized in that the filter body is set such that, with a ceramic layer formed on its surface and tilted at a set angle on the filter surface, the permeable particle size is smaller than the diameter of fine coffee grounds.

7. The method for forming a ceramic layer on the filter body of a metal mesh coffee filter according to claim 6, characterized in that the ceramic layer has pores with a diameter of 0.1 to 3 μm.

8. The method for forming a ceramic layer on the filter body of a metal mesh coffee filter according to claim 6, characterized in that the paint is bonded to the material of the coated surface by ionic bonding.

9. The method for forming a ceramic layer on the filter body of a metal mesh coffee filter according to claim 6, characterized in that the metal mesh is formed using a twill weave.

10. A method for forming a ceramic layer on the filter body of a metal mesh coffee filter according to claim 6, characterized in that the thickness of the ceramic layer is 4 to 8% of the diameter of the wire that performs the filtering action.

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