Filter element, filtration device body, filtration device, and filter unit

Abstract

To provide a filter element capable of inhibiting a filter part from being damaged by the pressure of a liquid to be filtered with a simple structure, a filter device body, a filter device, and a filter unit.SOLUTION: A filter element 1 includes a filter part 2 for removing contaminants from a liquid to be filtered through filtering parts 2A with the filtering parts 2A continuously folded into a wave shape to be annularly formed as a whole, an upper end holding member 3 arranged at an upper end part of the filter part 2 to hold the upper end part in a liquid-tight state and having an injection port 3H for injecting the liquid to be filtered into the filter part 2, a lower end holding member 4 arranged at a lower end part of the filter part 2 to hold the lower end part in a liquid-tight state, and expansion suppressing members 5 arranged at an outer periphery of the filter part 2 between the upper end holding member 3 and the lower end holding member 4 to suppress expansion of the filter part 2 in a radial direction when the liquid to be filtered is injected into the filter part 2 through the injection port 3H.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filter element, a filter device body, a filter device, and a filter unit for filtering a liquid to be filtered, such as a machining fluid or cutting oil, generated in a machine or the like. [Background technology]

[0002] For example, impurities such as sludge are contained in the fluids to be filtered, such as machining fluids and cutting oils generated in metalworking machines such as electric discharge machines. Therefore, filtration devices for filtering and reusing the machining fluids and cutting oils discharged from metalworking machines, and filter elements for use in filtration devices, are known.

[0003] Patent Document 1 discloses a filter element for filtering liquid. The filter element described in Patent Document 1 includes a filter assembly, an outer cylinder, a first end cap, and a second end cap. The filter assembly includes a main filter made of nonwoven fabric, a final filter made of nonwoven fabric, and cores inserted into the interior spaces of the main filter and the final filter. The filter element described in Patent Document 1 is used while being set in a housing.

[0004] The liquid to be filtered flows under pressure from the inner peripheral side to the outer peripheral side of the main filter. This completes the first filtration. At this time, the convex portion on the inner wall surface of the outer tube prevents the outer peripheral side of the main filter from expanding due to the pressure of the liquid to be filtered flowing from the inner cavity of the main filter to the outer peripheral side. The liquid to be filtered also flows from the outer peripheral side to the inner peripheral side of the final filter while maintaining pressure. This completes the second filtration. At this time, the core inserted into the inner cavity of the final filter supports the inner peripheral side of the final filter. In this way, the filter element disclosed in Patent Document 1 prevents the main filter and final filter from being damaged by the pressure of the liquid to be filtered. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-29984 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the filter element described in Patent Document 1 includes an outer cylinder, a main filter, a final filter, and a core. This makes the filter element structure complex and large. Furthermore, when the filter element is used, it is set in a housing that covers the filter element. This makes the device that uses the filter element large.

[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a filter element, a filtration device main body, a filtration device, and a filter unit that can prevent the filter part from being damaged by the pressure of the liquid to be filtered with a simple structure. [Means for solving the problem]

[0008] The above problem is solved by a filter element according to the present invention, which removes impurities from a liquid to be filtered by pouring the liquid to be filtered discharged from a machine into the filter element, the filter portion having a filtration section that is continuously folded in a wave-like pattern to form a ring as a whole, and which removes the impurities from the liquid to be filtered through the filtration section; an upper end holding member that is disposed at the upper end of the filter portion and holds the upper end in a liquid-tight state, and has an inlet for pouring the liquid to be filtered into the filter portion; a lower end holding member that is disposed at the lower end of the filter portion and holds the lower end in a liquid-tight state; and an expansion suppressing member that is disposed on the outer periphery of the filter portion between the upper end holding member and the lower end holding member, and which suppresses radial expansion of the filter portion when the liquid to be filtered is poured into the filter portion through the inlet.

[0009] According to the filter element of the present invention, an expansion suppression member disposed on the outer periphery of the filter portion between the upper end holding member and the lower end holding member suppresses radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through the inlet of the upper end holding member. Therefore, the expansion suppression member can prevent the filter portion from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion. Furthermore, the filter element does not include a member for covering the filter portion or a member for supporting the inside of the filter portion. Therefore, the filter portion can be prevented from being damaged by the pressure of the liquid to be filtered with a simple structure. Furthermore, the weight of the filter element can be reduced.

[0010] In the filter element according to the present invention, the filter portion, the upper end holding member, the lower end holding member, and the expansion suppressing member are preferably made of a combustible material.

[0011] According to the filter element of the present invention, the filter portion, upper end holding member, lower end holding member, and expansion suppression member are made of combustible materials. This makes it easy to incinerate the filter element. In other words, by incinerating the filter element, most of the filter portion, upper end holding member, lower end holding member, and expansion suppression member can be carbonized. As a result, by incinerating the filter element after filtration, metals (sludge) such as rare metals contained in the impurities removed from the filtered liquid by the filter portion can be extracted and recycled.

[0012] In the filter element according to the present invention, the upper end holding member and the lower end holding member are preferably made of a metal material.

[0013] In the filter element according to the present invention, the upper end holding member and the lower end holding member are made of a metal material, which more reliably prevents the filter portion from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion, and also prevents damage to the upper end holding member and the lower end holding member.

[0014] The above problem is solved by a filtration device main body according to the present invention, which houses a filter element that removes impurities from a liquid to be filtered when the liquid to be filtered discharged from a machine is poured into the filter element, the filtration device main body comprising: an annular peripheral part having an opening at an upper end and accommodating the filter element inserted through the opening; a bottom part closing the lower part of the annular peripheral part and supporting a lower end holding member of the filter element; a lid part that can open and close the opening of the annular peripheral part and, when the opening is closed, closes an inlet formed in the upper end holding member of the filter element for pouring the liquid to be filtered into the inside of the filter part of the filter element and holds the filter element together with the bottom part; and a discharge part that discharges liquid from which the impurities have been removed from the liquid to be filtered to the outside of the annular peripheral part, wherein the inner circumferential surface of the annular peripheral part suppresses radial expansion of the filter part when the liquid to be filtered is poured into the inside of the filter part through the inlet.

[0015] The filtration device main body according to the present invention uses the inner circumferential surface of the annular peripheral portion to suppress radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through an injection port formed in the upper end holding portion of the filter element. That is, the filtration device main body supports the outer circumferential portion of the filter portion of the filter element with the inner circumferential surface of the annular peripheral portion, suppressing radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion. Therefore, the filtration device main body can suppress damage to the filter portion due to the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion. Furthermore, because the filtration device main body that houses the filter element can suppress damage to the filter portion of the filter element, a simple structure can suppress damage to the filter portion due to the pressure of the liquid to be filtered, even if the filter element does not have a member for covering the filter portion or a member for supporting the inside of the filter portion.

[0016] In the filtration device main body of the present invention, the lid portion preferably has an inner lid member that presses the upper end holding member of the filter element to suppress expansion of the upper end holding member of the filter element when the liquid to be filtered is injected into the inside of the filter element through the injection port while the lid portion is closing the opening.

[0017] According to the filtration device main body of the present invention, the lid portion has an inner lid member. When the liquid to be filtered is poured into the filter element through the inlet while the lid portion closes the opening of the annular peripheral portion, the inner lid member presses against the upper end holding member of the filter element to suppress expansion of the upper end holding member of the filter element. This prevents damage to the filter portion due to the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion, and also prevents damage such as detachment of the upper end holding member, in which the inlet is formed, from the filter portion.

[0018] In the filtration device body according to the present invention, the lid portion preferably has a biasing means for biasing the inner lid member toward the upper end holding member of the filter element when the lid portion closes the opening.

[0019] According to the filter device main body of the present invention, the lid portion has a biasing means. The biasing means biases the inner lid member of the lid portion toward the upper end holding member of the filter element while the lid portion closes the opening of the annular peripheral portion. Therefore, even if there is "variation" in the height of the filter element (the length in the direction connecting the lid portion and the bottom of the filter device main body), the inner lid member is biased toward the upper end holding member of the filter element by the biasing means, more reliably pressing the upper end holding member of the filter element and more reliably suppressing the upper end holding member of the filter element from expanding. This more reliably prevents the upper end holding member of the filter element from becoming detached from the filter portion and being damaged.

[0020] In the filtration device main body of the present invention, the lid portion preferably has an injection pipe that is inserted into the inside of the filter element through the injection port when the lid portion closes the opening, and injects the liquid to be filtered into the inside of the filter element.

[0021] In the filtration device main body according to the present invention, the cover has an injection pipe. The injection pipe is inserted into the filter element through the injection port while the cover closes the opening of the annular peripheral portion, and injects the liquid to be filtered into the filter element. This allows the injection pipe to reliably inject the liquid to be filtered under pressure into the filter element through the injection port.

[0022] The filtration device body according to the present invention is preferably characterized by further comprising a push-up mechanism provided at the bottom for lifting the filter element housed inside the annular peripheral portion toward the opening of the annular peripheral portion.

[0023] According to the filtration device main body of the present invention, the filtration device main body further includes a lifting mechanism. The lifting mechanism is provided at the bottom of the filtration device main body and lifts the filter element housed inside the annular peripheral portion toward the opening of the annular peripheral portion. Therefore, the lifting mechanism lifts the filter element, which has become heavy due to the liquid to be filtered and impurities after the filtration process, toward the opening of the annular peripheral portion, making it easier for an operator to remove the filter element through the opening of the annular peripheral portion and supporting the operator's work.

[0024] The object is to provide a filter device comprising: a filter element into which a liquid to be filtered discharged from a machine is poured to remove impurities from the liquid to be filtered; and a filtration device body accommodating the filter element, wherein the filter element is formed into a ring shape as a whole by continuously folding a filtering portion in a wave-like shape, and the filter portion removes the impurities from the liquid to be filtered through the filtering portion; an upper end holding member disposed at an upper end of the filter portion, holding the upper end of the filter portion in a liquid-tight state, and having an inlet for pouring the liquid to be filtered into the filter portion; and a lower end holding member disposed at a lower end of the filter portion, holding the lower end of the filter portion in a liquid-tight state. The aforementioned problems are solved by the filtration device according to the present invention, which comprises a member, wherein the filtration device main body has an opening at an upper end, an annular peripheral part that houses the filter element inserted through the opening, a bottom part that closes the lower part of the annular peripheral part and supports the lower end holding member of the filter element, and a lid part that is capable of opening and closing the opening of the annular peripheral part, that closes the injection port when the opening is closed, and that holds the filter element together with the bottom part, and wherein the radial expansion of the filter part when the liquid to be filtered is injected into the filter part through the injection port is suppressed by the inner circumferential surface of the annular peripheral part.

[0025] According to the filtration device of the present invention, the filtration device main body uses the inner circumferential surface of the annular peripheral portion to suppress radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through an injection port formed in the upper end holding portion of the filter element. That is, the filtration device main body supports the outer circumferential portion of the filter portion of the filter element with the inner circumferential surface of the annular peripheral portion, suppressing radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion. Therefore, the filtration device main body can suppress damage to the filter portion due to the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion. Furthermore, because the filtration device main body that houses the filter element can suppress damage to the filter portion of the filter element, a simple structure can suppress damage to the filter portion due to the pressure of the liquid to be filtered, even if the filter element does not have a member for covering the filter portion or a member for supporting the inside of the filter portion.

[0026] In the filtration device of the present invention, the filter element preferably further has an expansion suppression member that is arranged on the outer periphery of the filter section between the upper end holding member and the lower end holding member and that suppresses radial expansion of the filter section when the liquid to be filtered is injected into the inside of the filter section through the inlet.

[0027] In the filtration device according to the present invention, an expansion suppression member disposed on the outer periphery of the filter portion between the upper end holding member and the lower end holding member of the filter element suppresses radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through the inlet of the upper end holding member. Therefore, the expansion suppression member can prevent the filter portion from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion. Furthermore, the filter element does not include any member for covering the filter portion or any member for supporting the inside of the filter portion. Therefore, the simple structure can prevent the filter portion from being damaged by the pressure of the liquid to be filtered. Furthermore, the weight of the filter element can be reduced.

[0028] In the filtration device according to the present invention, the lid portion preferably has an inner lid member that presses against the upper end holding member of the filter element to suppress expansion of the upper end holding member of the filter element when the liquid to be filtered is injected into the inside of the filter element through the injection port while the lid portion is closing the opening.

[0029] According to the filtration device of the present invention, the lid portion has an inner lid member. When the liquid to be filtered is poured into the filter element through the inlet while the lid portion closes the opening of the annular peripheral portion, the inner lid member presses against the upper end holding member of the filter element to suppress expansion of the upper end holding member of the filter element. This prevents the filtration device body from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion, and also prevents the upper end holding member, in which the inlet is formed, from being detached from the filter portion and being damaged.

[0030] In the filtration device according to the present invention, the lid portion preferably has a biasing means for biasing the inner lid member toward the upper end holding member of the filter element when the lid portion closes the opening.

[0031] According to the filtration device of the present invention, the lid portion has a biasing means. The biasing means biases the inner lid portion's member toward the upper end holding member of the filter element while the lid portion closes the opening of the annular peripheral portion. Therefore, even if there is "variation" in the height of the filter element (the length in the direction connecting the lid portion and the bottom of the filtration device body), the inner lid portion is biased toward the upper end holding member of the filter element by the biasing means, more reliably pressing the upper end holding member of the filter element and more reliably suppressing the upper end holding member of the filter element from expanding. This more reliably prevents the upper end holding member of the filter element from becoming detached from the filter portion and being damaged.

[0032] In the filtration device according to the present invention, the lid portion preferably has an injection pipe that is inserted into the inside of the filter element through the injection port when the lid portion closes the opening, and injects the liquid to be filtered into the inside of the filter element.

[0033] In the filtration device according to the present invention, the cover has an injection pipe that is inserted into the filter element through the injection port while the cover closes the opening of the annular peripheral portion, and injects the liquid to be filtered into the filter element. This allows the injection pipe to reliably inject the liquid to be filtered under pressure into the filter element through the injection port.

[0034] In the filtration device of the present invention, preferably, the filtration device main body further has a push-up mechanism provided at the bottom for lifting the filter element housed inside the annular peripheral portion toward the opening of the annular peripheral portion.

[0035] According to the filtration device of the present invention, the filtration device main body further includes a lifting mechanism. The lifting mechanism is provided at the bottom of the filtration device main body and lifts the filter element housed inside the annular peripheral portion toward the opening of the annular peripheral portion. Therefore, the lifting mechanism lifts the filter element, which has become heavy due to the liquid to be filtered and impurities after the filtration process, toward the opening of the annular peripheral portion, making it easier for an operator to remove the filter element through the opening of the annular peripheral portion and supporting the operator's work.

[0036] The filtration device according to the present invention preferably further comprises a filter element housing that houses the filter element and has liquid permeability that allows the liquid from which the impurities have been removed from the liquid to be filtered to pass through, and the filter element housing is provided inside the annular peripheral portion so that it can be freely attached and detached to the filtration device main body through the opening of the filtration device main body together with the filter element housed therein.

[0037] According to the filtration device of the present invention, the filter element housing accommodates the filter element and has liquid permeability that allows the passage of liquid removed from the liquid to be filtered. The filter element housing also has liquid permeability that allows the passage of liquid from which impurities have been removed. The filter element housing, with the filter element housed therein, is detachably mounted within the annular peripheral portion of the filtration device main body through an opening in the filtration device main body. Therefore, even if the filter element becomes heavy after filtration due to the liquid to be filtered and impurities, an operator can easily remove the filter element together with the filter element housing from the filtration device main body by removing the filter element housing from the filtration device main body. Furthermore, an operator can install a new filter element, for example, in the filter element housing and then place the new filter element inside the annular peripheral portion of the filtration device main body. This allows an operator to easily replace the filter element.

[0038] The above-mentioned problem is solved by a filter unit according to the present invention, which includes a filter element that removes impurities from the liquid to be filtered when the liquid to be filtered discharged from a machine is poured into the filter element, and a filter element container that houses the filter element and has liquid permeability that allows liquid after the impurities have been removed from the liquid to be filtered to pass through, wherein the filter element has a filtering section that is formed into a ring shape as a whole by continuously folding the filtering section in a wave-like pattern and that removes the impurities from the liquid to be filtered through the filtering section, an upper end holding member that is disposed at the upper end of the filter section and holds the upper end of the filter section in a liquid-tight state and has an inlet for pouring the liquid to be filtered into the filter section, and a lower end holding member that is disposed at the lower end of the filter section and holds the lower end of the filter section in a liquid-tight state, and wherein the filter element container, with the filter element housed therein, is characterized in that when the liquid to be filtered is poured into the filter section through the inlet, radial expansion of the filter section is suppressed by side portions.

[0039] In the filter unit according to the present invention, the filter element housing uses its side surfaces to suppress radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through an injection port formed in the upper end holding portion of the filter element. That is, the filter element housing supports the outer periphery of the filter portion of the filter element with its side surfaces, suppressing radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion. Therefore, the filter element housing can suppress damage to the filter portion due to the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion. Furthermore, because the filter element housing that houses the filter element can suppress damage to the filter portion of the filter element, a simple structure can suppress damage to the filter portion due to the pressure of the liquid to be filtered, even if the filter element does not include a member for covering the filter portion or a member for supporting the inside of the filter portion.

[0040] In the filter unit of the present invention, the filter element preferably further has an expansion suppression member that is arranged on the outer periphery of the filter section between the upper end holding member and the lower end holding member and that suppresses radial expansion of the filter section when the liquid to be filtered is injected into the inside of the filter section through the injection port.

[0041] According to the filter unit of the present invention, an expansion suppression member disposed on the outer periphery of the filter portion between the upper end holding member and the lower end holding member of the filter element suppresses radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through the inlet of the upper end holding member. Therefore, the expansion suppression member can prevent the filter portion from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion. Furthermore, the filter element does not include a member for covering the filter portion or a member for supporting the inside of the filter portion. Therefore, the simple structure can prevent the filter portion from being damaged by the pressure of the liquid to be filtered. Furthermore, the weight of the filter element can be reduced.

[0042] The above problem is solved by a filter unit according to the present invention, comprising: a filter element that removes impurities from the liquid to be filtered when the liquid to be filtered discharged from a machine is poured into the filter element; and a storage bag that houses the filter element and is formed of a resin mesh and has liquid permeability that allows liquid after the impurities have been removed from the liquid to be filtered to pass through, wherein the filter element has a filtering section that is formed into a ring shape by continuously folding the filtering section in a wave-like pattern as a whole and that removes the impurities from the liquid to be filtered through the filtering section; an upper end holding member that is disposed at the upper end of the filter section and holds the upper end of the filter section in a liquid-tight state and has an inlet for pouring the liquid to be filtered into the filter section; and a lower end holding member that is disposed at the lower end of the filter section and holds the lower end of the filter section in a liquid-tight state, and wherein the storage bag, with the filter element housed therein, is characterized in that when the liquid to be filtered is poured into the filter section through the inlet, the side portions of the storage bag suppress radial expansion of the filter section.

[0043] In the filter unit according to the present invention, the side surfaces of the storage bag suppress radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through an injection port formed in the upper end holding portion of the filter element. That is, the side surfaces of the storage bag support the outer periphery of the filter portion of the filter element, suppressing radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion. Therefore, the storage bag can suppress damage to the filter portion due to the pressure of the liquid to be filtered flowing from the inside of the filter portion to the outside of the filter portion. Furthermore, because the storage bag that houses the filter element can suppress damage to the filter portion of the filter element, a simple structure can suppress damage to the filter portion due to the pressure of the liquid to be filtered, even if the filter element does not have a member for covering the filter portion or a member for supporting the inside of the filter portion.

[0044] In the filter unit according to the present invention, the storage bag preferably has a reinforcing portion fixed to the side surface portion to reinforce the side surface portion and suppress radial expansion of the side surface portion.

[0045] In the filter unit according to the present invention, the side surfaces of the storage bag are reinforced by the reinforcing portions, which suppress radial expansion. Therefore, the side surfaces of the storage bag can more reliably suppress radial expansion of the filter unit when the liquid to be filtered is injected into the filter unit through the injection port formed in the upper end holding portion of the filter element. This more reliably prevents the filter unit from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter unit to the outside of the filter unit. [Effects of the Invention]

[0046] According to the present invention, it is possible to provide a filter element, a filtration device main body, a filtration device, and a filter unit that can prevent the filter portion from being damaged by the pressure of the liquid to be filtered with a simple structure. [Brief explanation of the drawings]

[0047] [Figure 1] 1 is a perspective view showing a first preferred embodiment of a filter element of the present invention, viewed obliquely downward from above. [Figure 2] 2 is a perspective view of the filter element of the first embodiment shown in FIG. 1, viewed obliquely from below in an upward direction. FIG. [Figure 3] Fig. 3(A) is a cross-sectional view showing an example of the internal structure of the filter element shown in Fig. 1 along the axial direction (vertical direction). Fig. 3(B) is a schematic diagram showing an example of the structure of a filter portion that constitutes the filter element. [Figure 4] Fig. 4(A) is a perspective view showing a filter unit having a filter element and a filter unit housing, and Fig. 4(B) is a front view showing the filter unit in a state where the filter element is housed in the filter unit housing. [Figure 5]FIG. 2 is a front view showing the filter device main body. [Figure 6] FIG. 6 is a vertical cross-sectional view of the filtration device body shown in FIG. 5. [Figure 7] 6 is a vertical cross-sectional view of the filtration device body taken along line KK in FIG. 5. [Figure 8] FIG. 7 is a cross-sectional view showing a state in which a cover of the filtration device main body shown in FIG. 6 is open. [Figure 9] FIG. 10 is a front view showing how the filter element is attached to the inside of the filtering device body. [Figure 10] FIG. 10 is a front view showing a state in which the filter element is attached inside the filter device main body and the inside of the filter device main body is sealed. [Figure 11] 10 is a cross-sectional view showing how the filtrate injection pipe is fitted into the filtrate injection opening of the upper end holding member of the filter element. FIG. [Figure 12] 10 is a perspective view showing an example of a structure in which the upper part of the filter element housing is opened when the filter element housing is pushed up. FIG. [Figure 13] Fig. 13(A) is a perspective view showing a filter unit having a filter element and a storage bag, and Fig. 13(B) is a front view showing the filter unit with the filter element stored in the storage bag. [Figure 14] FIG. 10 is a front view showing how a filter element according to a second embodiment of the present invention is mounted inside a filtering device main body. DETAILED DESCRIPTION OF THE INVENTION

[0048] Preferred embodiments of the present invention will now be described in detail with reference to the drawings. The embodiments described below are preferred examples of the present invention, and therefore various technically preferable limitations are applied thereto, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is particularly limited. Furthermore, in each drawing, similar components are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0049] (First embodiment) (Filter element 1) First, the filter element 1 will be described. FIG. 1 is a perspective view showing a first preferred embodiment of a filter element of the present invention, viewed obliquely downward from above. FIG. 2 is a perspective view of the filter element of the first embodiment shown in FIG. 1, viewed obliquely from below and obliquely upward. Fig. 3(A) is a cross-sectional view showing an example of the internal structure of the filter element shown in Fig. 1 along the axial direction (vertical direction). Fig. 3(B) is a schematic diagram showing an example of the structure of a filter portion that constitutes the filter element.

[0050] 1 and 2 is removably housed and held within a filtering device main body, which will be described later. The filter element 1 is filled with a liquid to be filtered, which is discharged from a machine such as a wire electric discharge machine or a metalworking machine, and removes impurities from the liquid, and then discharges the liquid resulting from the filtration.

[0051] The liquid to be filtered by the filter element 1 is circulated between the filter element 1 side and the machine side for reuse. The liquid to be filtered is, for example, machining fluid discharged from a wire electric discharge machine or cutting fluid discharged from a machine tool. The filter element 1 can also be called a filter device or a filtration unit. The filter element 1 generally includes a filter portion 2, an upper end holding member 3, a lower end holding member 4, and a bulge prevention member 5. The "bulge prevention member 5" of this embodiment is an example of the "expansion suppression member" of the present invention. All components of the filter element 1 may be made of materials that can be incinerated after use.

[0052] <Filter section 2> As shown in FIGS. 3(A) and 3(B), the filter unit 2 has an annular filtration portion 2A and a hollow portion 2B. The filter unit 2 is made of an incinerable material, such as nonwoven fabric, pulp-based paper, or a porous resin membrane. The most preferred material for the filter unit 2 is nonwoven fabric, but is not limited to this. The filtration portion 2A is continuously formed along the circumferential direction CL. The filtration portion 2A of the filter unit 2 has numerous fine pores 2S for removing impurities from the liquid to be filtered and discharging the remaining liquid. For example, the pores 2S are gaps between the fibers of the nonwoven fabric that form the filter unit 2. The filtration accuracy of the fine pores 2S of the filter unit 2 is, for example, approximately 0.5 μm, which is extremely high even among filter paper, but is not limited to this.

[0053] The overall shape of the filter unit 2 shown in Figures 3(A) and 3(B) is preferably, for example, substantially cylindrical. Note that in Figure 3(B), a part of the filtering portion 2A of the filter unit 2 is not shown in order to simplify the drawing.

[0054] 1 and 3, the filter unit 2 is annular as a whole when viewed from above, and the filtering section 2A of the filter unit 2 is pleated by being continuously folded along the circumferential direction so as to form an approximately V-shape or W-shape. Therefore, the annular filtering section 2A of the filter unit 2 has a plurality or many pleats 2P along the circumferential direction. However, the shapes of the filter unit 2 and the filtering section 2A are not limited to these.

[0055] This significantly increases the filtering area of ​​the filter section 2. Adjacent pleat sections 2P are formed by folding along the axial height L shown in Figures 3(A) and 3(B). As shown in Figure 3(B), a space 2C is formed between adjacent pleat sections 2P. After impurities have been removed from the liquid to be filtered, the remaining liquid can pass between adjacent pleat sections 2P.

[0056] <Upper end holding member 3 and lower end holding member 4> In this example, the upper end holding member 3 and the lower end holding member 4 shown in FIGS. 1 to 3 are circular or disk-shaped members made of an incinerable material, such as natural rubber, synthetic rubber, or resin. Alternatively, the upper end holding member 3 and the lower end holding member 4 do not necessarily have to be made of an incinerable material and may be made of a metal such as iron. The upper end holding member 3 is attached to surround the upper end 2M of the filter unit 2. The upper end holding member 3 holds the upper end 2M of the filter unit 2 in a liquid-tight state while preventing the upper end 2M of the filter unit 2 from expanding in the radial direction R due to the pressure of the liquid to be filtered being poured in. The "radial direction R" in this embodiment is an example of the "diameter direction" in the present invention. A liquid to be filtered injection opening 3H is provided in the center of the upper end holding member 3, allowing the liquid to be filtered to be poured into the hollow portion 2B of the filter unit 2. The "liquid to be filtered injection opening 3H" in this embodiment is an example of the "inlet" in the present invention.

[0057] The lower end holding member 4 is attached and arranged so as to surround the periphery of the lower end 2N of the filter part 2. The lower end holding member 4 holds the lower end 2N of the filter part 2 in a liquid-tight state while holding the lower end 2N of the filter part 2 to prevent the lower end 2N of the filter part 2 from expanding in the radial direction R due to the pressure of the injected liquid to be filtered.

[0058] <Bulge prevention material 5> 1 and 2, a plurality of expansion prevention members 5 are arranged on the outer periphery of the filter unit 2 between the upper end holding member 3 and the lower end holding member 4 so as to bind the outer periphery of the filter unit 2. The expansion prevention members 5 are preferably circular, endless strip-shaped members. The upper end holding member 3, the lower end holding member 4, and the expansion prevention members 5 prevent the filter unit 2 from expanding in the radial direction R even when the liquid to be filtered is injected under pressure into the hollow portion 2B through the liquid to be filtered injection opening 3H.

[0059] The bulge prevention members 5 can be made of an incinerable material, such as the same nonwoven fabric as the filter section 2, or synthetic or natural rubber, which are the materials of the upper end holding member 3 and the lower end holding member 4. As mentioned above, the upper end holding member 3 and the lower end holding member 4 may also be made of a metal such as iron. In the illustrated example, three bulge prevention members 5 are arranged, but one, two, four or more can be arranged depending on the axial length along the axial height L of the filter section 2.

[0060] In the filter element 1 according to this embodiment, the expansion prevention member 5, which is disposed on the outer periphery of the filter portion 2 between the upper end holding member 3 and the lower end holding member 4, suppresses radial expansion of the filter portion 2 when the liquid to be filtered is injected into the interior (hollow portion 2B) of the filter portion 2 through the liquid to be filtered injection opening 3H of the upper end holding member 3. Therefore, the expansion prevention member 5 can suppress damage to the filter portion 2 due to the pressure of the liquid to be filtered flowing from the interior of the filter portion 2 to the exterior of the filter portion 2. Furthermore, the filter element 1 does not include a member for covering the filter portion 2 or a member for supporting the interior of the filter portion 2. Therefore, the simple structure can suppress damage to the filter portion 2 due to the pressure of the liquid to be filtered. Furthermore, the weight of the filter element 1 can be reduced.

[0061] Furthermore, if the filter section 2, the upper end holding member 3, the lower end holding member 4, and the bulge prevention member 5 are made of combustible materials, the filter element 1 can be easily incinerated. That is, by incinerating the filter element 1, it is possible to carbonize most of the filter section 2, the upper end holding member 3, the lower end holding member 4, and the bulge prevention member 5. As a result, by incinerating the filter element 1 after the filtration process, metals (sludge) such as rare metals contained in the impurities removed from the filtered liquid by the filter section 2 can be extracted and recycled.

[0062] <Filter unit 7> Fig. 4(A) is a perspective view showing a filter unit having a filter element and a filter unit housing, and Fig. 4(B) is a front view showing the filter unit in a state where the filter element is housed in the filter unit housing. The filter unit 7 according to this embodiment includes the above-described filter element 1 and a filter element container 10.

[0063] As shown in FIGS. 4(A) and 4(B), the filter element holder 10 is a cylindrical member with a bottom made of a corrosion-resistant metal, such as stainless steel. The filter element holder 10 has an opening 11 and a bottom 12, and a peripheral surface, or side surface 14, has a number of circular through-holes 10H formed over the entire area. The filter element 1 can be inserted and held inside the filter element holder 10 through the opening 11. The filter element holder 10 has a number of through-holes 10H, which gives it liquid permeability, allowing liquid from which impurities have been removed from the liquid to be filtered to pass through. The filter element holder 10, with the filter element 1 housed (i.e., housed), is provided inside the filter device main body 20, described below, together with the filter element 1, so as to be detachable from the filter device main body 20.

[0064] The filter element housing 10 according to this embodiment uses the side portions 14 to suppress radial expansion of the filter portion 2 (specifically, the filtration portion 2A shown in FIG. 3(A)) when the liquid to be filtered is poured into the hollow portion 2B of the filter portion 2 through the liquid to be filtered pouring opening 3H formed in the upper end holding member 3 of the filter element 1. That is, the filter element housing 10 supports the outer periphery of the filter portion 2 of the filter element 1, and suppresses radial expansion of the filter portion 2 when the liquid to be filtered is poured into the hollow portion 2B of the filter portion 2.

[0065] Therefore, the filter element housing 10 can prevent the filter portion 2 from being damaged by the pressure of the liquid to be filtered that flows from the inside of the filter portion 2 to the outside of the filter portion 2. Furthermore, because the filter element housing 10 that houses the filter element 1 can prevent the filter portion 2 of the filter element 1 from being damaged, even if the filter element 1 is not provided with a member for covering the filter portion 2 or a member for supporting the inside of the filter portion 2, the simple structure of the filter element housing 10 can prevent the filter portion 2 from being damaged by the pressure of the liquid to be filtered.

[0066] Furthermore, even when the filter element housing 10 supports the outer periphery of the filter portion 2 of the filter element 1 and suppresses radial expansion of the filter portion 2 when the liquid to be filtered is poured into the hollow portion 2B of the filter portion 2, the liquid to be filtered can flow through the space 2C (see FIG. 3(B)) of the filter portion 2 to the outside of the filter portion 2 and pass through the numerous holes 10H of the filter element housing 10. In other words, even when the filter element housing 10 supports the outer periphery of the filter portion 2 of the filter element 1 with the side portion 14, the filter element housing 10 can suppress obstruction of the flow of the liquid to be filtered and ensure the flow of the liquid to be filtered.

[0067] As shown in FIG. 12, the filter element housing 10 is preferably divided into two halves 99 along the axial direction. The semicircular divided portions 12M of the bottom portion 12 are divided into two diametrically opposite each other and are connected by a hinge (not shown). Each of the halves 99 has a guide portion 97. Meanwhile, guide pins 88 are provided radially opposite each other on the inner upper portion of the annular peripheral portion 21 of the filter device main body 20. When the filter element 1 is housed in the filter element housing 10 as shown in FIG. 4(B), and the filter element housing 10 shown in FIG. 12 is pushed upward within the annular peripheral portion 21 of the filter device main body 20, the relative positions of the guide pins 88 and the guide portions 97 change, and the guide pins 88 fit into the guide portions 97, respectively. As a result, the half portions 99, 99 are pushed apart in the SS direction, making it easier to remove the filter element 1 from the filter element container 10.

[0068] (Filtering device body 20) Next, a filter device body 20 according to an embodiment of the present invention, which detachably houses the above-described filter element 1, will be described with reference to FIGS. FIG. 5 is a front view showing the filter device main body. FIG. 6 is a vertical cross-sectional view of the filtration device body shown in FIG. 7 is a vertical cross-sectional view of the filtration device body shown in FIG. 5 taken along line KK. FIG. 8 is a cross-sectional view showing the filtration device body shown in FIG. 6 with the cover open. For ease of explanation, FIG. 8 shows the inner lid member 34 and the injection part 40 disassembled from the lid body 31.

[0069] The filtration device main body 20 shown in Fig. 5 accommodates and detachably holds the filter element 1. As already explained, the filter element 1 removes impurities from the liquid to be filtered by pouring the liquid into the filter element 1. As shown in Fig. 5, the filtration device main body 20 generally has an annular peripheral portion 21, a bottom portion 22, a discharge portion 23, a lid portion 30, and legs 24.

[0070] The filtration device main body 20 is made of a metal material, such as stainless steel, that has excellent water resistance and corrosion resistance. The annular peripheral portion 21 has a circular opening 26 at its top. The bottom of the annular peripheral portion 21 is formed to be continuous with the bottom portion 22. The annular peripheral portion 21 and the bottom portion 22 form an annular container 25. The bottom portion 22 has a semi-elliptical cross section and closes the bottom of the annular peripheral portion 21. A discharge portion 23 is connected downward to the center of the bottom portion 22.

[0071] <Discharge section 23> The discharge section 23 discharges the liquid, from which impurities have been removed from the liquid to be filtered using the filter element 1, from the inside of the annular container 25 to the outside of the annular container 25. The legs 24 are formed in an annular shape, and the bottom section 22 is housed and fixed at its upper part. The legs 24 are installed on a fixing section (not shown), for example, on the floor side. As shown in FIG. 6 , the filter element 1 is detachably inserted through the opening 26 and housed inside the container 25 (specifically, the annular peripheral portion 21). The lower end of the filter element 1 is supported by a support plate 48 provided on the bottom section 22. In other words, the bottom section 22 supports the lower end holding member 4 of the filter element 1 via the support plate 48.

[0072] <Lid part 30> 5 to 8, the lid portion 30 is provided so as to be able to open and close the opening 26 at the top of the annular peripheral portion 21. The lid portion 30 is able to open and close the opening 26 of the annular peripheral portion 21, and also hermetically closes it. When the lid portion 30 closes the opening 26, it presses the upper end holding member 3 of the filter element 1 downward, thereby holding the filter element 1 between the lid portion 30 and the bottom portion 22 so as not to move in the up-down direction Z.

[0073] Next, a preferred structural example of the lid portion 30 will be described with reference to FIGS. The lid portion 30 has a lid body 31, an opening / closing hinge portion 32, a fixing portion 33, an inner lid member 34, and an injection portion 40 for the liquid to be filtered. The lid body 31 closes the opening 26 of the annular peripheral portion 21 in an openable and closable manner. The lid body 31 has a handle 35. An operator can hold the handle 35 to open and close the lid body 31. The lid body 31 has a semi-elliptical cross section.

[0074] As shown in FIG. 6, the opening / closing hinge portion 32 has a base portion 32A, a movable portion 32B, and a connecting pin 32C. One end of the base portion 32A is fixed to an upper position on the outer circumferential surface of the annular peripheral portion 21. One end of the movable portion 32B is fixed to the outer circumferential surface of the lid body 31. The other end of the base portion 32A and the other end of the movable portion 32B are connected to each other by the connecting pin 32C. This allows the lid body 31 to move about the connecting pin 32C from a state in which the lid body 31 closes the opening 26 as shown in FIG. 6 to a state in which the lid body 31 opens the opening 26 as shown in FIG. 8.

[0075] 6, the fixed part 33 has a base part 33A and a movable part 33B. The base part 33A is fixed to an upper position of the outer circumferential surface of the annular peripheral part 21. The movable part 33B is fixed to the outer circumferential surface of the lid body 31. As a result, when the lid body 31 closes the opening 26, the movable part 33B is detachably fixed to the base part 33A using a connecting member 33C.

[0076] The inner lid member 34 shown in Figures 6 to 8 is positioned relative to the inner flange of the lid body 31 by, for example, a pin. The inner lid member 34 and the lid body 31 form a double lid structure for closing the opening 26. As shown in Figure 8, the inner lid member 34 is a disk-shaped member and has a cylindrical portion 34B in the center. The cylindrical portion 34B is formed to protrude toward the inner surface of the lid body 31.

[0077] The cover 31 has a gas inlet 36 and a gas outlet 37. The gas inlet 36 can inject a gas such as air into the interior of the annular peripheral portion 21. A gas inlet pipe 81 is connected to the gas inlet 36. The gas inlet pipe 81 can introduce a gas such as air into the interior of the annular peripheral portion 21 through the gas inlet 36. The gas inlet pipe 81 is provided with an adjustment valve 82 and a check valve 83. The adjustment valve 82 can adjust the pressure of the gas injected into the interior of the annular peripheral portion 21. The check valve 83 prevents the gas injected into the interior of the annular peripheral portion 21 from flowing back out of the annular peripheral portion 21.

[0078] For example, an operator can reduce the pressure of the gas to be injected into the inside of the annular peripheral portion 21 using the adjustment valve 82 and introduce the gas into the inside of the annular peripheral portion 21 through the gas introduction pipe 81. This makes it possible to prevent the air pressure inside the annular peripheral portion 21 from becoming excessively high. This makes it possible to connect the gas introduction pipe 81 to the gas injection part 36 using a detachable connector such as a coupler, without using a fastening member such as a screw. This improves the operability when an operator connects the gas introduction pipe 81 to the gas injection part 36 and injects gas into the inside of the annular peripheral portion 21, and also makes it possible to miniaturize the connection structure between the gas injection part 36 and the gas introduction pipe 81.

[0079] Furthermore, for example, by rotating the filtered liquid injection pipe 41 in the RR direction, the anti-slip portion 44 of the filtered liquid injection pipe 41 moves up and down in the Z direction relative to the filtered liquid injection opening 3H of the upper end holding member 3 of the filter element 1, so that the position of the anti-slip portion 44 in the Z direction (up and down direction) can be adjusted.

[0080] <Injection section 40 for liquid to be filtered> The liquid to be filtered injection section 40 includes a liquid to be filtered injection pipe 41, a mounting member 42, and a spring 43. The "spring 43" in this embodiment is an example of the "biasing means" of the present invention. The liquid to be filtered injection pipe 41 is a pipe for injecting the liquid to be filtered, which is discharged from the machine and has a predetermined pressure, into the filter element 1 in the annular container 25. The liquid to be filtered injection pipe 41 is fitted into an insertion hole 31H formed in the center of the lid body 31 and held by a mounting member 42. The liquid to be filtered injection pipe 41 is held by the mounting member 42 and can be moved up and down in the Z direction by manually rotating the liquid to be filtered injection pipe 41, as shown by arrow RR in FIG. 7 . For example, by rotating the liquid to be filtered injection pipe 41, the inner lid member 34 can be pressed against the filter element 1.

[0081] Furthermore, the to-be-filtrated liquid injection pipe 41 passes through the cylindrical portion 34B of the inner lid member 34 and has a retaining portion 44 at the lower end of the to-be-filtrated liquid injection pipe 41. As shown in FIG. 6 , the retaining portion 44 of the to-be-filtrated liquid injection pipe 41 is fitted into the to-be-filtrated liquid injection opening 3H of the upper end holding member 3 of the filter element 1, and is thereby caught on the inner surface of the upper end holding member 3. In this way, when the lid member 30 closes the opening 26, the to-be-filtrated liquid injection pipe 41 of the injection part 40 is inserted into the to-be-filtrated liquid injection opening 3H, thereby blocking the to-be-filtrated liquid injection opening 3H. This ensures a reliable connection between the to-be-filtrated liquid injection pipe 41 and the filter element 1, allowing the to-be-filtrated liquid to be directly injected into the filter element 1 via the to-be-filtrated liquid injection pipe 41.

[0082] As shown in FIGS. 6 and 7 , the spring 43 is disposed between the inner surface of the lid body 31 and the upper surface of the inner lid member 34. The spring 43 is a biasing means that applies a biasing force to the inner lid member 34 to tightly contact the upper surface of the upper-end holding member 3 of the filter element 1 when the lid body 31 closes the opening 26. That is, the spring 43 biases the inner lid member 34 toward the upper-end holding member 3 of the filter element 1. As a result, as shown in FIG. 6 , when the lid body 31 closes the opening 26, the inner lid member 34 presses the upper end of the filter element 1 downward, holding the filter element 1 between the inner lid member 34 and the bottom 22. Furthermore, the inner lid member 34 prevents the upper-end holding member 3 of the filter element 1 from floating up in the annular container 25 when the liquid to be filtered is injected under pressure through the liquid to be filtered injection opening 3H via the liquid to be filtered injection pipe 41. Therefore, the liquid to be filtered can be fed to the filter element 1 under a predetermined pressure.

[0083] <Gap SP> 7 and 8, a gap SP is formed between the outer periphery of the filter element 1 and the inner circumferential surface of the annular peripheral portion 21. The range of values ​​that the gap SP can assume is preferably, for example, approximately 1 mm or more and 3 mm or less. In the example shown in FIGS. 6 to 8, the filter element 1 is housed in the annular peripheral portion 21 while housed in the filter element housing 10. However, the filter element 1 does not necessarily have to be housed in the annular peripheral portion 21 while housed in the filter element housing 10, and may be housed alone in the annular peripheral portion 21.

[0084] <Support plate 48> As shown in Figures 6 and 7, the bottom 22 of the annular peripheral portion 21 has a disk-shaped support plate 48. The support plate 48 supports the lower end holding member 4 of the housed filter element 1. The outer diameter of the support plate 48 is larger than that of the lower end holding member 4, and it has a number of holes 49. These holes 49 allow the liquid that has passed through the filter element 1 to fall toward the bottom 22. The liquid from which impurities have been removed is then discharged from the annular container 25 to the outside through the discharge portion 23 shown in Figure 5. For example, the support plate 48 rests on a number of support legs 48B fixed to the inner surface of the bottom 22.

[0085] <Push-up mechanism section 50> Next, the push-up mechanism 50 will be described with reference to FIGS. The push-up mechanism 50 is provided inside the leg 24 and attached to the bottom 22. The push-up mechanism 50 lifts the filter element 1 housed in the annular peripheral part 21 from the inside of the annular peripheral part 21 toward the opening 26. The push-up mechanism 50 is foot-operated to push up the filter element 1 in the Z1 direction (see FIG. 8). The push-up mechanism 50 has a vertical operation unit 51, a foot pedal 52, and a link 53.

[0086] As shown in FIGS. 6 and 8 , the up / down operation unit 51 has a fixed part 54 placed on the floor and a movable part 55. A plate 59 is fixed to the movable part 55. A substantially L-shaped foot pedal 52 is rotatably connected to the fixed part 54 by a pin 56. The foot pedal 52 has a foot tip 57 and a connecting part 58. The connecting part 58 is connected to one end of a link 53 by a pin. The other end of the link 53 is connected to the plate 59 by a pin. A boost member 60 is provided on the upper surface of the plate 59 and protrudes in the Z1 direction. The boost member 60 abuts against the lower surface of the support plate 48. Alternatively, the boost member 60 is connected to the lower surface of the support plate 48.

[0087] 4, when the filter element 1 is housed in the annular peripheral portion 21 while housed in the filter element holder 10, the filter element 1 is placed on the support plate 48 via the filter element holder 10. Alternatively, when only the filter element 1 is housed in the annular peripheral portion 21 without using the filter element holder 10, the filter element 1 is placed directly on the support plate 48.

[0088] 8, when the operator presses down the foot pedal tip 57 in the V direction, the foot pedal 52 rotates around the pin 56. This causes the movable part 55 to be pushed up in the Z1 direction relative to the fixed part 54. The push-up member 60 can mechanically push up the filter element 1 together with the support plate 48 by a predetermined stroke SK in the Z1 direction.

[0089] The reason why the filter element 1 is mechanically pushed up in this manner is that a used filter element 1 contains liquid from which impurities have been removed from the liquid to be filtered, and is therefore heavier than a dried filter element 1. This allows an operator to easily and safely remove the used, heavy filter element 1 from the opening 26 of the annular peripheral portion 21. Note that instead of an operator lifting the filter element 1 by foot, the push-up mechanism 50 may be configured to automatically lift the filter element 1 using an actuator such as an electric motor.

[0090] (filtration device 100) Next, the filtration device 100 will be described. As shown in FIGS. 6 to 8, the filtration device 100 includes the above-described filter element 1 that filters impurities from a liquid to be filtered, and the above-described filtration device main body 20 that houses the filter element 1.

[0091] <How to use the filtration device 100 and an example of the filtration operation of the liquid to be filtered> A method of using the above-described filtration device 100 and an example of a filtration operation for filtering a liquid to be filtered will now be described. FIG. 9 is a front view showing how the filter element is attached inside the filtering device body. FIG. 10 is a front view showing a state in which the filter element is attached inside the filter device main body and the inside of the filter device main body is sealed. As shown in FIG. 9, by opening the cover 31 of the cover part 30 of the filter device body 20, the filter element 1 is attached into the annular peripheral part 21 of the filter device body 20 through the opening 26.

[0092] More specifically, as shown in FIG. 9 , the filter element 1 is already housed in the filter element holder 10. That is, in the description of this embodiment, a case will be exemplified in which the filter unit 7 with the filter element 1 housed in the filter element holder 10 is attached to the filtering device main body 20. The filter element 1 housed in the filter element holder 10 in this manner is lowered in the Z2 direction from its suspended state and housed in the annular peripheral portion 21 through the opening 26. As a result, the filter element 1 housed in the filter element holder 10 is placed on the support plate 48, as shown in FIG. 9 . Note that, unlike the example shown in FIG. 9 , the filter element 1 alone may be housed in the annular peripheral portion 21 without using the filter element holder 10. In this case, the filter element 1 is placed directly on the support plate 48.

[0093] Next, as shown in Fig. 9, when the cover body 31 is rotated in the X direction, the cover body 31 seals the opening 26. When the cover member closes the opening 26, the inner cover member 34 presses the upper end holding member 3 of the filter element 1 in the Z2 direction (downward). More preferably, the spring 43 applies a biasing force to the inner cover member 34 against the upper surface of the upper end holding member 3 of the filter element 1 while the cover body 31 closes the opening 26. As a result, as shown in Fig. 10, the inner cover member 34 presses the upper end holding member 3 of the filter element 1 and holds the filter element 1 between the inner cover member 34 and the bottom 22 while the cover body 31 closes the opening 26.

[0094] FIG. 11 is a cross-sectional view showing how the filtrate injection pipe is fitted into the filtrate injection opening of the upper end holding member of the filter element. As shown in FIG. 11 , the retaining portion 44 of the liquid to be filtered injection pipe 41 is fitted into the liquid to be filtered injection opening 3H of the upper end holding member 3 of the filter element 1 and is caught on the inner surface 3R of the upper end holding member 3. The inner lid member 34 prevents the upper end holding member 3 of the filter element 1 from floating up within the annular container 25 when the liquid to be filtered is injected under pressure through the liquid to be filtered injection opening 3H via the liquid to be filtered injection pipe 41. The inner lid member 34 seals the opening 26 of the annular container 25. This ensures a reliable connection between the liquid to be filtered injection pipe 41 and the filter element 1 due to the retaining portion 44 and the elastic force of the spring 43. Therefore, the liquid to be filtered, which is under a predetermined pressure, is smoothly, reliably, and directly injected into the filter element 1 via the liquid to be filtered injection pipe 41.

[0095] 10, the liquid to be filtered that has been injected into the filter element 1 (specifically, the hollow portion 2B) spreads in the filter element 1 along the radial direction R from the inside to the outside of the filter element 1. The filtration section 2A of the filter unit 2 shown in FIG. 3 filters out impurities from the liquid to be filtered and discharges the remaining liquid.

[0096] As a result, the filter element 1 removes impurities from the liquid to be filtered, producing a filtered liquid. The filtered liquid obtained by passing through the filter element 1 passes through the filter element housing 10 shown in FIG. 10 and falls toward the support plate 48. It then passes through the numerous holes 49 in the support plate 48, falls to the bottom 22, and collects in the center of the bottom 22. The liquid that has reached the bottom 22 can then be discharged from the annular container 25 to the outside via the discharge portion 23. This liquid can be reused for further machining.

[0097] As described above, the liquid to be filtered flows under pressure from the inside to the outside of the filter element 1 in the radial direction R. At this time, the filtering portion 2A of the filter unit 2 tends to expand outward due to the pressure of the liquid to be filtered. In contrast, the filtering device main body 20 according to this embodiment uses the inner circumferential surface of the annular peripheral portion 21 to suppress radial expansion of the filter unit 2 (specifically, the filtering portion 2A) when the liquid to be filtered is injected into the hollow portion 2B of the filter unit 2 through the liquid to be filtered injection opening 3H formed in the upper end holding member 3 of the filter element 1. That is, the filtering device main body 20 supports the outer periphery of the filter unit 2 of the filter element 1 with the inner circumferential surface of the annular peripheral portion 21, thereby suppressing radial expansion of the filter unit 2 when the liquid to be filtered is injected into the hollow portion 2B of the filter unit 2. Therefore, the filtering device main body 20 can suppress damage to the filter unit 2 due to the pressure of the liquid to be filtered flowing from the inside of the filter unit 2 to the outside of the filter unit 2. Furthermore, since the filtration device main body 20 that houses the filter element 1 can prevent damage to the filter portion 2 of the filter element 1, even if the filter element 1 is not provided with components for covering the filter portion 2 or components for supporting the inside of the filter portion 2, the simple structure can prevent the filter portion 2 from being damaged by the pressure of the liquid to be filtered.

[0098] Furthermore, even when the filtration device main body 20 supports the outer periphery of the filter portion 2 of the filter element 1 with the inner circumferential surface of the annular peripheral portion 21 and suppresses radial expansion of the filter portion 2 when the liquid to be filtered is poured into the hollow portion 2B of the filter portion 2, the liquid to be filtered can flow through the space 2C (see FIG. 3(B)) of the filter portion 2 to the outside of the filter portion 2 and pass through the filter element housing 10 toward the bottom 22. In other words, even when the filtration device main body 20 supports the outer periphery of the filter portion 2 of the filter element 1 with the inner circumferential surface of the annular peripheral portion 21, obstruction of the flow of the liquid to be filtered can be suppressed and the flow of the liquid to be filtered can be ensured.

[0099] Furthermore, when the liquid to be filtered is poured into the filter element 1 through the liquid-to-be-filtered inlet opening 3H with the lid portion 30 closing the opening 26 of the annular peripheral portion 21, the inner lid member 34 presses the upper end holding member 3 of the filter element 1, suppressing expansion of the upper end holding member 3 of the filter element 1. This makes it possible for the filtration device main body 20 to suppress damage to the filter portion 2 due to the pressure of the liquid to be filtered flowing from the inside of the filter portion 2 to the outside of the filter portion 2, and also to suppress damage to the upper end holding member 3, in which the liquid-to-be-filtered inlet opening 3H is formed, due to detachment from the filter portion 2, for example.

[0100] Furthermore, the spring 43 biases the inner lid member 34 of the lid portion 30 toward the upper end holding member 3 of the filter element 1 while the lid portion 30 closes the opening 26 of the annular peripheral portion 21. Therefore, even if there is "variation" in the height of the filter element 1 (the length in the direction connecting the lid portion 30 and the bottom portion 22 of the filtering device main body 20), the inner lid member 34 is biased toward the upper end holding member 3 of the filter element 1 by the spring 43, more reliably pressing the upper end holding member 3 of the filter element 1 and more reliably suppressing expansion of the upper end holding member 3 of the filter element 1. This more reliably prevents the upper end holding member 3 of the filter element 1 from coming off the filter portion 2 and being damaged.

[0101] <Replacing used filter element 1> Next, the case of replacing a used filter element 1 with a new filter element 1 will be described. FIG. 12 is a perspective view showing an example of a structure in which the upper part of the filter element housing is opened when the filter element housing is pushed up. 10 , when a filtering operation for a liquid to be filtered is performed and, for example, an operator or the like replaces the used filter element 1 with a new filter element 1, first, a gas such as air is injected into the inside of the annular peripheral portion 21 through the gas injection portion 36 provided on the lid 31, thereby discharging the liquid contained in the filter element 1 and the filter element housing 10 to the outside of the inside of the annular peripheral portion 21 through the discharge portion 23. This makes it possible to reduce the weight of the filter element 1 and the filter element housing 10 compared to before the gas was injected into the inside of the annular peripheral portion 21.

[0102] 10 to 9, the cover 31 is lifted in the X1 direction and opened to expose the opening 26. This releases the filter element 1 from the state held between the inner cover member 34 and the bottom 22. In addition, the retaining portion 44 of the filtrate-containing liquid injection pipe 41 is removed from the filtrate-containing liquid injection opening 3H of the upper-end holding member 3 of the filter element 1.

[0103] As shown in Figure 8, when an operator or the like presses down the foot pedal tip 57 of the vertical operation unit 51 in the V direction, the foot pedal 52 rotates around the pin 56. As a result, the movable unit 55 is pushed up in the Z1 direction relative to the fixed unit 54. As a result, the operator or the like can mechanically push up the filter element 1 housed in the filter element housing 10 together with the support plate 48 by a predetermined stroke SK in the Z1 direction by using the lift-up member 60 while standing, without having to crouch down. In other words, the vertical operation unit 51 can easily and safely push up the filter element 1 and the filter element housing 10, which have become heavy due to the removal of impurities from the liquid to be filtered, by the stroke SK shown in Figure 8, from within the annular container 25.

[0104] 12, when the filter element housing 10 is pushed upward within the annular peripheral portion 21 of the filtering device main body 20, the guide pins 88, 88 fit into the guide portions 97, 98, respectively, and the half portions 99, 99 can be pushed apart in the SS direction. This makes it easier to remove the filter element 1 shown in FIG. 4(B) from the filter element housing 10, improving the workability of removal.

[0105] For example, a lifting machine (not shown) can grasp and lift the upper edge portion 10R (see FIG. 9) of the pushed-up filter element housing 10 to remove the filter element 1 contained in the filter element housing 10 from the annular container 25. In this way, the used, heavy filter element 1 and filter element housing 10 can be easily and safely removed from the opening 26 of the annular peripheral portion 21. Note that a worker or the like may also grasp and lift the upper edge portion 10R (see FIG. 9) of the filter element housing 10 instead of using a machine to remove the filter element 1 contained in the filter element housing 10 from the annular container 25.

[0106] As described above, in the filtration device 100 according to this embodiment, the filter element holder 10, with the filter element 1 housed therein, is provided inside the annular peripheral portion 21 of the filtration device main body 20 through the opening 26 of the filtration device main body 20 so as to be detachable from the filtration device main body 20 together with the filter element 1. Therefore, even if the filter element 1 becomes heavy after the filtration process due to the presence of the liquid to be filtered and impurities, an operator can easily remove the filter element 1 together with the filter element holder 10 from the filtration device main body 20 by removing the filter element holder 10, which is formed of a resin mesh, from the filtration device main body 20. Furthermore, an operator can install a new filter element 1 in the filter element holder 10 and then place the new filter element 1 inside the annular peripheral portion 21 of the filtration device main body 20. This allows an operator to easily replace the filter element 1.

[0107] <Incineration of used filter elements 1> Next, the incineration treatment of the used filter element 1 will be described. As shown in Figures 3(A) and 3(B), the filter section 2 of the filter element 1 has an annular filtering section 2A as a whole and a hollow section 2B, and is made of, for example, nonwoven fabric, pulp-based paper, or a porous resin film. The upper and lower holding members 3 and 4 of the filter section 2 are made of, for example, natural rubber, synthetic rubber, or resin. The expansion prevention member 5 is made of the same material as the filter section 2 or the upper and lower holding members 3 and 4.

[0108] Therefore, if the upper end holding member 3 and the lower end holding member 4 are made of, for example, natural rubber, synthetic rubber, or resin, the used filter element 1 does not contain any metal parts and is carbonized by incineration as is. By carbonizing the used filter element 1 as is, almost no filter element 1 remains, leaving only the metal (sludge) that is the impurity filtered from the liquid to be filtered. Therefore, only the metal can be extracted from the filter element 1, allowing for the recycling of valuable metals such as iron, copper, aluminum, and stainless steel. Furthermore, in filter elements in which the filter portion and the metal container that houses the filter portion are integrated, the filter element must be disassembled to recycle the metal (sludge) that is the impurity. Alternatively, the filter element may be discarded as is. The filtration device 100 according to this embodiment eliminates such disassembly and disposal.

[0109] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS.

[0110] <Filter unit 7 and storage bag 110> Fig. 13(A) is a perspective view showing a filter unit having a filter element and a storage bag, and Fig. 13(B) is a front view showing the filter unit with the filter element stored in the storage bag. FIG. 14 is a front view showing how a filter element according to the second embodiment of the present invention is mounted inside the filtering device main body.

[0111] A filter unit 7 according to a second embodiment of the present invention includes the filter element 1 described above and a storage bag 110. The storage bag 110 is liquid permeable and allows the remaining liquid to pass through after impurities have been removed from the liquid to be filtered. The storage bag 110 is, for example, a cylindrical container made of a mesh or net-like resin material. The top of the storage bag 110 has an opening 111. The bottom of the storage bag 110 has a bottom 112 and is closed. The side of the storage bag 110 has a side portion 114 that is connected to the bottom 112. The storage bag 110 can store the entire filter element 1 in a removable manner.

[0112] Examples of materials that can be used to form the storage bag 110 include resins containing polyester, resins containing nylon, resins containing polyethylene, resins containing Teflon (registered trademark), resins containing polypropylene, resins containing polyether ether ketone (PEEK), and resins containing polyphenylene sulfide (PPS). However, the materials that can be used to form the storage bag 110 are not limited to these.

[0113] 13(A) and 13(B), the storage bag 110 has a first reinforcing part 113 and a second reinforcing part 115. The first reinforcing part 113 and the second reinforcing part 115 are examples of the "reinforcing part" of the present invention, and are, for example, strips formed by weaving cloth or resin.

[0114] The first reinforcing portion 113 is provided in an annular shape on the side surface portion 114 and fixed thereto, and reinforces the side surface portion 114. That is, the first reinforcing portion 113 is a circular, endless, strip-shaped member and is fixed to the side surface portion 114.

[0115] The second reinforcing portion 115 is fixed to the bottom portion 112 and the side portion 114 and extends from the bottom portion 112 through the side portion 114 toward the opening 111. As shown in FIG. 13(A), the portions of the second reinforcing portion 115 fixed to the bottom portion 112 intersect with each other. This allows the portions of the second reinforcing portion 115 fixed to the bottom portion 112 to more reliably reinforce the bottom portion 112 of the storage bag 110. Also, as shown in FIG. 13(A), the portion of the second reinforcing portion 115 near the opening 111 is spaced from the side portion 114, forming an annular space. Therefore, the middle portion 151 of the second reinforcing portion 115 can function as a grip. For example, a worker or the like can use the middle portions 151 to carry the storage bag 110 containing the filter element 1. The storage bag 110 can be reused repeatedly. The storage bag 110 can also be made of a material that can be incinerated together with the filter element 1. The storage bag 110 of this embodiment, with the filter element 1 housed (i.e., stored) therein, is provided inside the filter device main body 20, described below, together with the filter element 1, so as to be detachable from the filter device main body 20.

[0116] The storage bag 110 shown in Figures 13(A) and 13(B) has four first reinforcing portions 113. However, the number of first reinforcing portions 113 is not limited to four and may be three or less, or five or more. Furthermore, in the storage bag 110 shown in Figures 13(A) and 13(B), the second reinforcing portion 115 is formed of a single belt-shaped member. However, the second reinforcing portion 115 is not limited to being formed of a single belt-shaped member and may be formed of multiple belt-shaped members.

[0117] 14, the filter unit 7 according to this embodiment is placed in the filtering device main body 20 along the Z2 direction, and the lid 30 is fastened. The side surface 114 of the storage bag 110 prevents the filter portion 2 (specifically, the filtration portion 2A) from expanding radially when the liquid to be filtered is poured into the hollow portion 2B of the filter portion 2 through the liquid-to-be-filtered pouring opening 3H formed in the upper end holding member 3 of the filter element 1 shown in FIG. 13(A). That is, the storage bag 110 supports the outer periphery of the filter portion 2 of the filter element 1 with the side surface 114, thereby preventing the filter portion 2 from expanding radially when the liquid to be filtered is poured into the hollow portion 2B of the filter portion 2. Therefore, the storage bag 110 can prevent the filter portion 2 from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter portion 2 toward the outside of the filter portion 2. Furthermore, since the storage bag 110 that houses the filter element 1 can prevent damage to the filter portion 2 of the filter element 1, even if the filter element 1 is not provided with components for covering the filter portion 2 or components for supporting the inside of the filter portion 2, the simple structure can prevent the filter portion 2 from being damaged by the pressure of the liquid to be filtered.

[0118] Furthermore, even when the storage bag 110 supports the outer periphery of the filter portion 2 of the filter element 1 with the side surface portions 114 and suppresses radial expansion of the filter portion 2 when the liquid to be filtered is poured into the hollow portion 2B (see FIG. 3) of the filter portion 2, the liquid to be filtered can flow through the space 2C (see FIG. 3(B)) of the filter portion 2 to the outside of the filter portion 2 and pass through the storage bag 110. In other words, even when the storage bag 110 supports the outer periphery of the filter portion 2 of the filter element 1 with the side surface portions 114, it is possible to suppress obstruction of the flow of the liquid to be filtered and ensure the flow of the liquid to be filtered.

[0119] As described above, the storage bag 110 has the first reinforcing portion 113 and the second reinforcing portion 115. The first reinforcing portion 113 and the second reinforcing portion 115 reinforce the side surface portion 114 and can suppress radial expansion of the side surface portion 114. Therefore, the side surface portion 114 of the storage bag 110 can more reliably suppress radial expansion of the filter portion 2 (specifically, the filtration portion 2A shown in FIG. 3(A)) when the liquid to be filtered is injected into the hollow portion 2B of the filter portion 2 through the liquid to be filtered injection opening 3H formed in the upper end holding member 3 of the filter element 1. This makes it possible for the storage bag 110 to more reliably prevent the filter portion 2 from being damaged by the pressure of the liquid to be filtered flowing from the inside of the filter portion 2 toward the outside of the filter portion 2.

[0120] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. The configurations of the above embodiments can be partially omitted or arbitrarily combined in a different manner from the above. [Explanation of symbols]

[0121] 1: filter element, 2: filter portion, 2A: filtration portion, 2B: hollow portion, 2C: space, 2M: upper end portion, 2N: lower end portion, 2P: pleated portion, 2S: hole, 3: upper end holding member, 3H: opening for injecting liquid to be filtered, 3R: inner surface, 4: lower end holding member, 5: bulge prevention member, 7: filter unit, 10: filter element container, 10H: hole, 11: opening, 12: bottom portion, 13: first reinforcing portion, 14: side portion, 15: second reinforcing portion, 20: filtration device main body, 21: surrounding portion, 22: bottom portion, 23: discharge portion, 24: leg portion, 25: container, 26: opening portion, 30: lid portion, 31: lid body, 31H: insertion hole, 32: opening / closing hinge portion, 32A: base, 32B: movable part, 32C: connecting pin, 33: fixed part, 33A: base, 33B: movable part, 33C: connecting member, 34: inner lid member, 34B: cylindrical part, 35: handle, 36: gas inlet part, 37: gas outlet part, 40: inlet part, 41: filtered liquid inlet pipe, 42: mounting member, 43: spring, 44: retaining part, 48: support plate, 48B: support leg, 49: hole, 50: lifting mechanism, 51: up and down operation part, 52: foot pedal, 53: link, 54: fixed part, 55: movable part, 56: pin, 57: foot pedal tip, 58: connecting part, 59: plate, 60: lifting member, 81: gas inlet pipe, 82: Adjusting valve, 83: Check valve, 84: Gas exhaust pipe, 100: Filtering device, 110: Storage bag, 151: Intermediate portion, CL: Circumferential direction, D1: Outer diameter, D2: Inner diameter, L: Height, R: Radial direction, SP: Gap, Z: Vertical direction

Claims

1. A filtration device body that houses a filter element that removes impurities from the liquid to be filtered by being poured into the filtration device body, an annular peripheral portion having an opening at an upper end thereof for receiving the filter element inserted through the opening; a bottom portion that closes the lower portion of the annular peripheral portion and supports a lower end holding member of the filter element; a lid portion that can open and close the opening of the annular peripheral portion, and that, when the opening is closed, blocks an inlet formed in an upper end holding member of the filter element for injecting the liquid to be filtered into the inside of the filter portion of the filter element, and that holds the filter element together with the bottom portion; a discharge section that discharges the liquid from which the impurities have been removed to the outside of the annular peripheral portion; Equipped with The lid portion is an inner lid member that presses the upper end holding member of the filter element when the lid portion closes the opening; an injection pipe that is inserted into the filter element through the injection port while the lid closes the opening and injects the liquid to be filtered into the filter element; and the injection pipe passes through the inner lid member and has a retaining portion that is fitted into the injection port and is caught on the inner surface side of the upper end holding member, A filtration device body characterized in that, when the liquid to be filtered is injected into the inside of the filter section through the inlet, the radial expansion of the filter section is suppressed by the inner surface of the annular surrounding portion, and the expansion of the upper end holding member is suppressed by the inner lid member pressing against the upper end holding member.

2. 2. The filter device body according to claim 1, wherein the lid portion has a biasing means for biasing the inner lid member toward the upper end holding member of the filter element when the lid portion closes the opening.

3. 3. The filtration device body according to claim 1, further comprising a push-up mechanism provided at the bottom portion for lifting the filter element housed inside the annular peripheral portion toward the opening of the annular peripheral portion.

4. a filter element into which the liquid to be filtered discharged from the machine is poured to remove impurities from the liquid to be filtered; a filter device body that houses the filter element; Equipped with The filter element is a filter section having a filtration portion continuously folded in a wave shape to form a ring as a whole, which removes the impurities from the liquid to be filtered through the filtration portion; an upper end holding member that is disposed at an upper end of the filter unit and holds the upper end of the filter unit in a liquid-tight state, and that has an inlet for injecting the liquid to be filtered into the filter unit; a lower end holding member that is disposed at a lower end of the filter unit and holds the lower end of the filter unit in a liquid-tight state; and The filtration device body includes: an annular peripheral portion having an opening at an upper end thereof for receiving the filter element inserted through the opening; a bottom portion that closes a lower portion of the annular peripheral portion and supports the lower end holding member of the filter element; a lid portion that can open and close the opening of the annular peripheral portion, and that closes the injection port when the opening is closed and holds the filter element together with the bottom portion; and The lid portion is an inner lid member that presses the upper end holding member of the filter element when the lid portion closes the opening; an injection pipe that is inserted into the filter element through the injection port while the lid closes the opening and injects the liquid to be filtered into the filter element; and the injection pipe passes through the inner lid member and has a retaining portion that is fitted into the injection port and is caught on the inner surface side of the upper end holding member, When the liquid to be filtered is injected into the filter section through the inlet, radial expansion of the filter section is suppressed by the inner surface of the annular peripheral portion, and expansion of the upper end holding member is suppressed by the inner lid member pressing against the upper end holding member.

5. 5. The filtration device according to claim 4, wherein the filter element further includes an expansion suppression member disposed on the outer periphery of the filter portion between the upper end holding member and the lower end holding member, the expansion suppression member suppressing radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through the inlet.

6. 5. The filtering device according to claim 4, wherein the lid portion has a biasing means for biasing the inner lid member toward the upper end holding member of the filter element when the lid portion closes the opening.

7. The filtration device according to any one of claims 4 to 6, characterized in that the filtration device main body further has a push-up mechanism provided at the bottom and configured to lift the filter element housed inside the annular peripheral portion toward the opening of the annular peripheral portion.

8. The filter element container further includes a filter element container that contains the filter element and has liquid permeability that allows the liquid from which the impurities have been removed from the liquid to be filtered to pass through. The filtration device according to any one of claims 4 to 7, characterized in that the filter element container is provided inside the annular peripheral portion so that it can be freely attached and detached to the filtration device main body through the opening of the filtration device main body together with the filter element housed therein.

9. The filtration device described in Claim 8, characterized in that the filter element container is a cylindrical member having a bottom and has a pair of half portions divided into two along the axial direction of the cylindrical member.

10. The bottom has a pair of divided sections that are divided into two along the radial direction of the cylindrical member, The filtering device according to claim 9, wherein the pair of divided portions are connected to each other.

11. The filtration device body further has a guide pin protruding radially from the inside of the annular peripheral portion, The filtration device described in claim 9, characterized in that the pair of half portions have a pair of guide portions into which the guide pin fits when the filter element housing is pushed up toward the opening inside the annular peripheral portion, and the guide pin fits into the pair of guide portions to expand radially.

12. a filter element into which the liquid to be filtered discharged from the machine is poured to remove impurities from the liquid to be filtered; a filter element container that contains the filter element and has liquid permeability that allows the liquid from which the impurities have been removed from the liquid to be filtered to pass; Preparation, The filter element is a filter section having a filtration portion continuously folded in a wave shape to form a ring as a whole, which removes the impurities from the liquid to be filtered through the filtration portion; an upper end holding member that is disposed at an upper end of the filter unit and holds the upper end of the filter unit in a liquid-tight state, and that has an inlet for injecting the liquid to be filtered into the filter unit; a lower end holding member that is disposed at a lower end of the filter unit and holds the lower end of the filter unit in a liquid-tight state; and The filter element container is a cylindrical member having a bottom, and has a pair of halves divided along an axial direction of the cylindrical member, a filter element housing configured to house the filter element and, when the liquid to be filtered is injected into the filter unit through the inlet, suppress radial expansion of the filter unit with its side portions;

13. The bottom has a pair of divided sections divided into two along the radial direction of the cylindrical member, The filter unit according to claim 12, wherein the pair of divided portions are connected to each other.

14. The filter unit according to claim 12, characterized in that the filter element further has an expansion suppression member that is disposed on the outer periphery of the filter section between the upper end holding member and the lower end holding member and that suppresses radial expansion of the filter section when the filtered liquid is injected into the interior of the filter section through the inlet.

15. a filter element into which the liquid to be filtered discharged from the machine is poured to remove impurities from the liquid to be filtered; a storage bag that houses the filter element and is made of a resin mesh and has liquid permeability that allows the liquid from which the impurities have been removed from the liquid to be filtered to pass through; Preparation, The filter element is a filter section having a filtration portion continuously folded in a wave shape to form a ring as a whole, which removes the impurities from the liquid to be filtered through the filtration portion; an upper end holding member that is disposed at an upper end of the filter unit and holds the upper end of the filter unit in a liquid-tight state, and that has an inlet for injecting the liquid to be filtered into the filter unit; a lower end holding member that is disposed at a lower end of the filter unit and holds the lower end of the filter unit in a liquid-tight state; and the storage bag, with the filter element accommodated in it, uses its side portions to suppress radial expansion of the filter portion when the liquid to be filtered is injected into the filter portion through the inlet, and has a first reinforcing portion that is annularly provided and fixed to the side portions to reinforce the side portions, and a second reinforcing portion that is fixed to the bottom and the side portions and extends from the bottom through the side portions toward an opening formed in the upper part to reinforce the bottom and the side portions.

16. A filter unit as described in Claim 15, characterized in that the portions of the second reinforcing portion fixed to the bottom intersect with each other.

17. A filter unit as described in Claim 15, characterized in that the opening portion of the second reinforcing portion is separated from the side portion and forms an annular space.

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