Medical filter

Abstract

A medical filter (10) comprises a housing (12), an inflow port (14), a filter medium (18), an outflow port (16), and a reinforcing material (19). The reinforcing material (19) allows a fluid (49) that has passed through the filter medium (18) to pass therethrough, and suppresses deformation of the filter medium (18) due to the pressure of the fluid (49) passing through the filter medium (18). The reinforcing material (19) covers the filter medium (18) in an outflow region (42) of an internal space (30) of the housing (12). The reinforcing material (19) has parallel sections (51) and tapered sections (53) connected to the parallel sections (51) in a state in which the fluid (49) passes through.

Description

Medical Filters

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to medical filters.

[0002] Japanese Patent Laid-Open Publication No. 7-67952 discloses a medical filter. The medical filter has a housing, an inlet port, an outlet port, and a filter material. The housing has an internal space. The inlet port and the outlet port are each fixed to the periphery of the housing. The filter material is fixed to the housing and disposed in the internal space of the housing. The filter material divides the internal space of the housing into an inlet region and an outlet region. Liquid (blood) flows into the inlet region through the inlet port. The filter material blocks the passage of specific components (white blood cells) of the liquid that flows into the inlet region. The liquid that passes through the filter material flows into the outlet region. The liquid that flows into the outlet region flows out of the housing through the outlet port.

[0003] Japanese Patent Application Publication No. 7-67952

[0004] When the filter medium is made of a soft material such as polyurethane, the pressure of the liquid flowing into the inlet region and passing through the filter medium can cause the filter medium to deform. This deformation can increase the pore size of the filter medium, allowing certain components to pass through the filter medium. This can result in a decrease in the filter medium's filtration performance.

[0005] The present invention aims to solve the above-mentioned problems.

[0006] (1) An aspect of the present invention is a medical filter comprising: a housing having an internal space; an inlet port fixed to the peripheral portion of the housing for allowing liquid to flow into the internal space from outside the housing; a filter material fixed to the housing and arranged in the internal space; an outlet port fixed to the peripheral portion for allowing the liquid that has passed through the filter material to flow out to the outside; and a reinforcing material through which the liquid that has passed through the filter material can pass and which suppresses deformation of the filter material due to the pressure of the liquid passing through the filter material; wherein the filter material divides the internal space into an inlet region into which the liquid flows in through the inlet port and an outlet region through which the liquid that has passed through the filter material flows out to the outside through the outlet port; and the reinforcing material covers the filter material in the outlet region, and when the liquid is passing through, has a parallel portion and a tapered portion connected to the parallel portion.

[0007] This configuration can prevent the filter medium from being deformed by the pressure of the liquid flowing into the inflow area and passing through the filter medium, thereby preventing a decrease in the filtering performance of the filter medium due to deformation of the filter medium.

[0008] (2) In the medical filter described in (1) above, the reinforcing material may have lower extensibility than the filtering material.

[0009] This configuration effectively prevents the filter medium from being deformed by the pressure of the liquid flowing into the inflow region and passing through the filter medium.

[0010] (3) In the medical filter described in (1) or (2) above, the filter material may be formed in a bag shape, the inside of the filter material may be the inlet region, the inlet port may penetrate the base end of the filter material and be inserted into the inlet region, and the reinforcing material may be formed in a bag shape to cover the outer surface of the filter material.

[0011] With this configuration, the filter material can be easily covered with the reinforcing material.

[0012] (4) In the medical filter described in (3) above, the base end of the filter material, the inlet port, and the base end of the reinforcing material may be integrally fixed to the peripheral edge of the housing.

[0013] This configuration allows the filter medium, inlet port, and reinforcing material to be easily secured inside the housing.

[0014] (5) In the medical filter described in (3) or (4) above, the outer surface of the filtering material and the inner surface of the reinforcing material may be in contact with each other.

[0015] This configuration effectively prevents the filter medium from being deformed by the pressure of the liquid passing through the filter medium.

[0016] (6) In the medical filter described in (5) above, the filtering material and the reinforcing material may be integrally formed.

[0017] According to this configuration, the filter medium and the reinforcing material can be easily manufactured.

[0018] (7) In the medical filter described in any one of (3) to (6) above, the parallel portion may be parallel to the axial direction of the inlet port, and the tapered portion may be inclined with respect to the axial direction and connected to the parallel portion so as to surround the parallel portion.

[0019] With this configuration, when liquid flows into the inlet area, the pressure of the liquid can effectively prevent the filter material from expanding in a direction perpendicular to the axial direction of the inlet port (in the thickness and width directions of the housing).

[0020] (8) In the medical filter described in any one of (1) to (7) above, the filter material may be a porous material that allows the liquid to pass through, and the reinforcing material may be a porous material having a pore size larger than the pore size of the filter material.

[0021] With this configuration, it is possible to prevent the liquid that has passed through the filter material from being blocked by the reinforcing material.

[0022] (9) In the medical filter described in (8) above, the reinforcing material may be a nonwoven fabric.

[0023] This configuration makes it easy to cover the filter material with the reinforcing material in the outflow area.

[0024] According to the present invention, it is possible to prevent the filter medium from being deformed by the pressure of the liquid flowing into the inflow region and passing through the filter medium, thereby preventing a decrease in the filtering performance of the filter medium due to deformation of the filter medium.

[0025] FIG. 1 is a front view of a medical filter according to a first embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIGS. 4A and 4B are partial cross-sectional views showing other exemplary configurations of a filter medium. FIG. 5 is a front view of a medical filter according to a first embodiment with liquid flowing into the inflow region. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view of a medical filter. FIG. 8 is a cross-sectional view of a medical filter. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 5. FIG. 10 is a front view of a medical filter according to a comparative example with liquid flowing into the inflow region. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 10. FIG. 13 is a front view of a medical filter according to a second embodiment. FIG. 14 is a front view of a medical filter according to a third embodiment. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14. Fig. 16 is a front view of a medical filter according to a fourth embodiment, and Fig. 17 is a cross-sectional view taken along line XVII-XVII in Fig. 16 .

[0026] A medical filter 10 according to a first embodiment will be described with reference to FIGS. 1 to 9. The medical filter 10 is a filter for filtering a liquid 49 (see FIGS. 6 and 9). The medical filter 10 is a filter for preventing the passage of predetermined components in the liquid 49. The medical filter 10 may be a filter for preventing the passage of predetermined components in blood (e.g., white blood cells). Of FIGS. 1 to 9, FIGS. 1 to 4B show the medical filter 10 in an initial state in which no liquid 49 is being supplied. FIGS. 5 to 9 show the medical filter 10 in a state in which the liquid 49 is being supplied.

[0027] As shown in FIGS. 1-3, medical filter 10 includes a housing 12, an inlet port 14, an outlet port 16, a filter medium 18, and a reinforcement material 19.

[0028] The housing 12 is a rectangular bag. The housing 12 has a first sheet portion 20 and a second sheet portion 22. The first sheet portion 20 and the second sheet portion 22 are two separate flexible sheets. The first sheet portion 20 and the second sheet portion 22 are transparent sheets. The first sheet portion 20 and the second sheet portion 22 are rectangular sheets of the same size and thickness. The first sheet portion 20 and the second sheet portion 22 are made of a synthetic resin. Specifically, examples of materials that can be used for the first sheet portion 20 and the second sheet portion 22 include thermoplastic elastomers such as soft vinyl chloride, polyurethane, ethylene-vinyl acetate copolymer, hydrogenated styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer or hydrogenated products thereof, and mixtures of thermoplastic elastomers with softeners such as polyolefins and ethylene-ethyl acrylate.

[0029] The housing 12 is formed into a bag shape by overlapping the first sheet portion 20 and the second sheet portion 22 and fusing the outer edge 24 of the first sheet portion 20 and the outer edge 26 of the second sheet portion 22. The first sheet portion 20 and the second sheet portion 22 may be fused together by external heat fusing using heat sealing. Alternatively, the first sheet portion 20 and the second sheet portion 22 may be fused together by internal heat fusing using a high-frequency welder, an ultrasonic welder, or the like. In the following description, "fusing" includes the above-mentioned external heat fusing and internal fusing.

[0030] The fused outer edge portions 24, 26 of the first sheet portion 20 and the second sheet portion 22 form a peripheral edge portion 28 of the housing 12. Furthermore, by fusing the outer edge portions 24, 26 of the first sheet portion 20 and the second sheet portion 22, an internal space 30 is formed inside the housing 12. In the following description, the fused portion of the housing 12 will be referred to as a fused region 32. In Figure 1, the fused region 32 is shown by a two-dot chain line.

[0031] Alternatively, the housing 12 may be formed by folding a single flexible sheet, overlapping the sheets, and fusing the outer edges of the flexible sheet. In this case, one portion of the folded flexible sheet becomes the first sheet portion 20, and the other portion becomes the second sheet portion 22.

[0032] As shown in FIGS. 1 and 2 , the inflow port 14 is a tubular member. The inflow port 14 is provided at a first end 31, which is one end of the housing 12. Specifically, the inflow port 14 penetrates the first end 31 of the peripheral edge 28 of the housing 12 and is inserted into the internal space 30 of the housing 12. The inflow port 14 is fixed to the peripheral edge 28 of the housing 12 by being fused to the first end 31 of the housing 12. The inflow port 14 is made of, for example, a synthetic resin. The inflow port 14 allows a liquid 49, such as blood (see FIGS. 6 and 9 ), to flow from the outside of the housing 12 into the internal space 30 of the housing 12.

[0033] The outlet port 16 is a cylindrical member of the same size and shape as the inlet port 14. The outlet port 16 is provided at the second end 33, which is the other end of the housing 12. Specifically, the outlet port 16 penetrates the second end 33 of the peripheral edge 28 of the housing 12 and is inserted into the internal space 30 of the housing 12. The outlet port 16 is fixed to the peripheral edge 28 of the housing 12 by being fused to the second end 33 of the housing 12. The constituent material of the outlet port 16 is the same as the constituent material of the inlet port 14. The outlet port 16 allows the liquid 49 in the internal space 30 of the housing 12 to flow out of the housing 12.

[0034] The inlet port 14 and the outlet port 16 are fixed to a peripheral edge 28 of the housing 12 while facing each other. That is, the inlet port 14 and the outlet port 16 are fixed coaxially to the housing 12. The inlet port 14 and the outlet port 16 are arranged on a central axis 34 of the inlet port 14.

[0035] The filter medium 18 is disposed in the internal space 30 of the housing 12. The filter medium 18 is formed in a rectangular shape when viewed from the front in FIG. 1 . The filter medium 18 is formed in a bag shape when viewed in cross section in FIG. 2 . The filter medium 18 is fused to the housing 12, thereby being fixed to the housing 12. As shown in FIG. 1 , the filter medium 18 is fixed to the housing 12 coaxially with the central axis 34. A base end 36 of the filter medium 18 faces the inlet port 14. A tip end 38 of the filter medium 18 faces the outlet port 16.

[0036] The filter medium 18 is a porous body made of synthetic resin or synthetic fiber. Examples of materials for the filter medium 18 include polyester, polyamide, polypropylene, polyethylene, polyurethane, polyvinyl chloride, acrylonitrile, and styrene-based elastomers. The pore size and thickness of the porous body can be appropriately selected depending on the blood component to be separated and removed from blood. For example, when the blood component to be separated and removed from blood is white blood cells, a porous body with an average pore size of 3 μm to 20 μm is preferred.

[0037] The filter medium 18 is formed by folding one rectangular flexible sheet 35 made of the above-mentioned constituent materials into a U-shape and fusing the outer edges of the folded flexible sheet 35. Therefore, the filter medium 18 is formed into a bag shape by fusing the outer edges of the one flexible sheet 35. Alternatively, the filter medium 18 may be formed into a bag shape by overlapping two flexible sheets 35 made of the above-mentioned constituent materials and fusing the outer edges of the two flexible sheets 35.

[0038] The filter media 18 may be formed as shown in Figures 4A and 4B.

[0039] The filter medium 18 shown in FIG. 4A is formed by stacking a plurality of rectangular flexible sheets 35, folding them into a U-shape, and fusing the outer edges of the folded flexible sheets 35 together.

[0040] The filter medium 18 shown in Figure 4B is formed into a bag shape by stacking multiple rectangular flexible sheets 35 and fusing the outer edges of the multiple flexible sheets 35. Specifically, one sheet body 39 made up of multiple overlapping flexible sheets 35 and another sheet body 39 made up of multiple overlapping flexible sheets 35 are prepared. The outer edge of one sheet body 39 is fused to the outer edge of the other sheet body 39, forming the filter medium 18 into a bag shape. In this case, the outer edge of one sheet body 39 is the outer edge of the multiple flexible sheets 35 that make up the one sheet body 39. The outer edge of the other sheet body 39 is the outer edge of the multiple flexible sheets 35 that make up the other sheet body 39.

[0041] 1 and 2, the inlet port 14 is inserted into the base end 36 of the bag-shaped filter medium 18. That is, the inlet port 14 is in communication with the interior of the filter medium 18. The housing 12, the base end 36 of the filter medium 18, and the inlet port 14 are fused together. As a result, the base end 36 of the filter medium 18 and the inlet port 14 are fixed to the housing 12 as a unit.

[0042] The filter medium 18 divides the interior space 30 of the housing 12 into an inlet region 40 and an outlet region 42. Specifically, the inlet region 40 is the space inside the filter medium 18. The inlet region 40 communicates with the outside of the housing 12 via the inlet port 14. A liquid 49 (see FIGS. 6 and 9 ) flows into the inlet region 40 via the inlet port 14.

[0043] The filter 18 prevents passage of predetermined components (e.g., white blood cells in blood) in the liquid 49 that has flowed into the inflow region 40. The filter 18 allows passage of components of the liquid 49 other than the predetermined components.

[0044] The outflow region 42 is a space outside the filter medium 18 within the internal space 30 of the housing 12. The outflow region 42 is in communication with the outlet port 16. Liquid 49 that has passed through the filter medium 18 flows into the outflow region 42. The liquid 49 that has flowed into the outflow region 42 flows out of the housing 12 via the outlet port 16.

[0045] When liquid 49 flows into the inflow region 40, the filter medium 18 is subjected to the pressure of the liquid 49. The reinforcing material 19 is disposed in the internal space 30 to suppress deformation of the filter medium 18 due to the pressure of the liquid 49. For this reason, the reinforcing material 19 is made of a material that is harder than the filter medium 18 and has lower extensibility (tensile elongation) than the filter medium 18, as will be described later.

[0046] Specifically, the reinforcing material 19 covers the outer surface of the filter medium 18 in the outflow region 42. Because the filter medium 18 is formed in a bag shape, the reinforcing material 19 is formed in a bag shape so as to cover the outer surface of the filter medium 18. Therefore, the entire outer surface of the filter medium 18 is covered with the reinforcing material 19. The filter medium 18 and the reinforcing material 19 overlap each other. That is, the outer surface of the filter medium 18 and the inner surface of the reinforcing material 19 are in contact with each other. In this case, the outer surface of the filter medium 18 and the inner surface of the reinforcing material 19 may be fused together. The filter medium 18 and the reinforcing material 19 may be molded integrally. Furthermore, as shown in FIGS. 4A and 4B , when the filter medium 18 is formed by stacking multiple flexible sheets 35, the reinforcing material 19 is arranged to cover the outer surface of the outermost flexible sheet 35.

[0047] When liquid 49 flows into the inflow region 40, the filter medium 18 receives the pressure of the liquid 49 and expands in a direction perpendicular to the axial direction of the inflow port 14. As the filter medium 18 expands in a direction perpendicular to the axial direction of the inflow port 14, the tip 38 side of the filter medium 18 (the bottom of the filter medium 18) is pulled (pulled up) toward the inflow port 14. The axial direction of the inflow port 14 is the direction along the central axis 34. The directions perpendicular to the axial direction of the inflow port 14 are the width direction and thickness direction of the housing 12. The width direction of the housing 12 is also the width direction of the filter medium 18 and the reinforcing material 19. The thickness direction of the housing 12 is also the thickness direction of the filter medium 18 and the reinforcing material 19. In Figures 6 to 9, the shapes of the filter material 18 and the reinforcing material 19 when liquid 49 is flowing into the inflow region 40 are shown by solid lines, and the shapes of the filter material 18 and the reinforcing material 19 in the initial state when liquid 49 has not flowed into the inflow region 40 are shown by dashed double-dashed lines.

[0048] As described above, the reinforcing material 19 covers the outer surface of the filter medium 18. Therefore, when liquid 49 flows into the inflow region 40 and passes through the filter medium 18, the reinforcing material 19 also receives the pressure of the liquid 49 and expands in a direction perpendicular to the axial direction of the inflow port 14. More specifically, when liquid 49 flows into the inflow region 40, the pressure of the liquid 49 is evenly applied inside the filter medium 18. As a result, the filter medium 18 tends to expand in the thickness and width directions of the filter medium 18. As described above, the reinforcing material 19 is provided on the outside of the filter medium 18 and is harder and has a lower tensile elongation than the filter medium 18. As a result, the pressure of the liquid 49 is evenly applied, thereby preventing the filter medium 18 from expanding in the thickness and width directions. Furthermore, the tip portion 55 (bottom portion) of the reinforcing material 19 is relatively soft. Therefore, when the liquid 49 flows into the inflow region 40 and the reinforcing material 19 is subjected to the pressure of the liquid 49, the tip 55 side of the reinforcing material 19 is pulled up toward the inflow port 14. Figure 6 shows a state in which the tip 55 side (bottom) of the reinforcing material 19 and the tip 38 side (bottom) of the filter medium 18 are slightly pulled up toward the inflow port 14 compared to before the liquid 49 flows into the inflow region 40 (two-dot chain line). Figure 7 shows a state in which the bottom of the reinforcing material 19 and the bottom of the filter medium 18 are pulled up flat toward the inflow port 14. Figure 8 shows a state in which the bottom of the reinforcing material 19 and the bottom of the filter medium 18 are pulled up toward the inflow port 14, with the central portions of each bottom being recessed toward the inflow port 14.

[0049] When liquid 49 flows into the inlet region 40, the reinforcing member 19 expands into a hexagonal shape when viewed in the width direction of the housing 12 (see FIG. 6 ). Also, the reinforcing member 19 expands into a hexagonal shape when viewed in the axial direction of the inlet port 14 (see FIG. 9 ).

[0050] That is, when the liquid 49 is flowing into the inflow region 40, the reinforcing material 19 has two parallel portions 51 and a tapered portion 53. In other words, when the liquid 49 is flowing into the inflow region 40, the reinforcing material 19 has two parallel portions 51 and a tapered portion 53.

[0051] Each of the two parallel portions 51 is a portion of the reinforcing material 19 that is parallel to the central axis 34. Each of the two parallel portions 51 is a flat portion that is parallel to the central axis 34. The two parallel portions 51 face each other across the central axis 34. Compared to the initial state, each of the two parallel portions 51 is spaced apart from the central axis 34 in the thickness direction of the housing 12. In other words, each of the two parallel portions 51 protrudes in the thickness direction of the housing 12 compared to the initial state.

[0052] The tapered portion 53 is connected to the two parallel portions 51. The tapered portion 53 is connected to the two parallel portions 51 so as to surround each of the two parallel portions 51. The tapered portion 53 is inclined with respect to the central axis 34. Specifically, the base end side of the tapered portion 53 connects the base end portion 37 of the reinforcing material 19 to the two parallel portions 51. Therefore, the base end side of the tapered portion 53 is inclined from the two parallel portions 51 toward the base end portion 37 of the reinforcing material 19. Furthermore, the tip side of the tapered portion 53 is inclined from the two parallel portions 51 toward the tip portion 55 of the reinforcing material 19. Furthermore, the side portion of the tapered portion 53 between the tip side and the base side of the tapered portion 53 is inclined toward the side edge of the reinforcing material 19.

[0053] The reinforcing material 19 does not have any folds to form boundaries between the two parallel portions 51 and the tapered portion 53. When the liquid 49 flows into the inflow region 40 and is subjected to the pressure of the liquid 49 that has passed through the filter medium 18, the two parallel portions 51 and the tapered portion 53 are formed. Also, in FIG. 6 , in the axial direction of the inflow port 14, the width L6 of each of the two parallel portions 51 is greater than the width L7 of the base end of the tapered portion 53 and the width L8 of the tip end of the tapered portion 53 (L6 > L7, L6 > L8). Furthermore, as shown in FIG. 9 , in the width direction of the housing 12, the width L9 of each of the two parallel portions 51 is greater than the widths L10 and L11 of the sides of the tapered portion 53 (L9 > L10, L9 > L11).

[0054] When liquid 49 has flowed into inflow region 40, two parallel portions 51 and tapered portion 53 are formed in reinforcing material 19, so even if filter medium 18 expands under the pressure of liquid 49, the expansion of filter medium 18 is suppressed inside reinforcing material 19. In other words, the expansion of filter medium 18 is suppressed to a shape that conforms to the inner surface of reinforcing material 19. This makes it possible to suppress large expansion of filter medium 18 in the thickness and width directions of housing 12.

[0055] When the inflow of the liquid 49 into the inflow region 40 stops, the reinforcing material 19 and the filter medium 18 return to their original shapes (the shapes in the initial state).

[0056] The reinforcing material 19 is a porous body through which the liquid 49 that has passed through the filter medium 18 can pass. The pore size of the porous body that constitutes the reinforcing material 19 is the same as the pore size of the porous body that constitutes the filter medium 18. Alternatively, the pore size of the porous body that constitutes the reinforcing material 19 is larger than the pore size of the porous body that constitutes the filter medium 18. In this case, the porous body that constitutes the reinforcing material 19 is coarser than the porous body that constitutes the filter medium 18. Therefore, the reinforcing material 19 does not filter the liquid 49 that has passed through the filter medium 18. In other words, the reinforcing material 19 does not function as a filter for the liquid 49.

[0057] Furthermore, the reinforcing material 19 is a porous material that is harder than the filter medium 18 and less extensible than the filter medium 18. Therefore, when the filter medium 18 and the reinforcing material 19 are subjected to the same force (for example, the pressure of the liquid 49), the reinforcing material 19 is less likely to stretch than the filter medium 18. In other words, the reinforcing material 19 has higher rigidity against tensile forces than the filter medium 18.

[0058] The porous material constituting the reinforcing material 19 may be, for example, a nonwoven fabric made of PET. In the case of a nonwoven fabric made of PET, the diameter of the fibers constituting the nonwoven fabric is preferably about 0.3 μm to 20 μm. In addition, the weight per unit area of ​​the nonwoven fabric per 0.1 mm of thickness is 10 g / m. 2 ~60g / m 2 The weight per unit area is preferably about 20 g / m 2 ~50g / m 2 It is more preferable that the degree of

[0059] Furthermore, the surface of the porous body (e.g., nonwoven fabric) that constitutes the reinforcing material 19 may be coated with a hydrophilic polymer or an antithrombogenic material, thereby improving the permeability of platelets through the nonwoven fabric.

[0060] A pre-filter may be provided inside the filter medium 18. The pre-filter separates and removes aggregates and the like from blood. When the pre-filter is made of nonwoven fabric, the diameter of the fibers constituting the nonwoven fabric is preferably about 5 μm to 30 μm. The weight per unit area of ​​the nonwoven fabric per 0.1 mm of thickness is preferably 10 g / m. 2 ~40g / m 2 The weight per unit area is preferably about 15 g / m 2 ~35g / m 2 It is more preferable that the degree of

[0061] Alternatively, the reinforcing material 19 may be formed using a mesh-like member that is less extensible than the filter medium 18 and has a larger pore size than the filter medium 18 .

[0062] The reinforcing material 19 may be made of a porous material having lower extensibility (tensile elongation) than the filter medium 18. Therefore, the reinforcing material 19 may be made of a porous material made of a material other than PET. Alternatively, the porous material making up the reinforcing material 19 may be a porous material having lower extensibility than the filter medium 18 and made of the same material as the filter medium 18.

[0063] The tensile elongation of the reinforcing material 19 will be described in detail. When viewed from the axial direction of the inlet port 14, the ratio of the circumferential length of the reinforcing material 19 when liquid 49 has flowed into the inlet region 40 to the circumferential length of the reinforcing material 19 when liquid 49 has flowed into the inlet region 40 is referred to as the tensile elongation of the reinforcing material 19. In this case, the tensile elongation of the reinforcing material 19 is preferably 0% to 40%. The tensile elongation is more preferably 0% to 35%. The tensile elongation is even more preferably 0% to 30%. The tensile elongation is even more preferably 0% to 25%. The tensile elongation is even more preferably 0% to 20%. By setting the tensile elongation of the reinforcing material 19 in this manner, it is possible to effectively suppress the expansion of the filter medium 18 in the width and thickness directions of the housing 12 when liquid 49 flows into the inlet region 40.

[0064] As shown in FIGS. 1 and 2, the fused region 32 includes a peripheral fused region 50 and a filter media fused region 52 .

[0065] The peripheral fused region 50 is a fused portion between the outer edge 24 of the first sheet portion 20 and the outer edge 26 of the second sheet portion 22 at the peripheral edge 28 of the housing 12. In the peripheral fused region 50, the outer edge 24 of the first sheet portion 20 and the outer edge 26 of the second sheet portion 22 are directly fused together.

[0066] The peripheral fused region 50 is integrally fused to the inlet port 14 and outlet port 16 .

[0067] The opening of the inlet port 14 on the outlet port 16 side (the opening communicating with the inlet region 40) is located at the filter medium fused region 52. Alternatively, the opening of the inlet port 14 on the outlet port 16 side may be located closer to the outlet port 16 than the filter medium fused region 52.

[0068] The filter medium fused region 52 is formed inward in the width direction of the housing 12 relative to the peripheral fused region 50. The filter medium fused region 52 is a fused portion of the housing 12 with the filter medium 18. The filter medium fused region 52 extends along the width direction of the housing 12 (the left-right direction in FIGS. 1 and 3 ), which is perpendicular to the axial direction of the inlet port 14 and the thickness direction of the housing 12.

[0069] As shown in Fig. 1, the filter medium fused region 52 is connected to the peripheral fused region 50. Specifically, both ends of the filter medium fused region 52 in the width direction and the base end of the filter medium fused region 52 in the axial direction are connected to the peripheral fused region 50. The filter medium fused region 52 is integrally fused to the base end 36 of the filter medium 18, the base end 37 of the reinforcing material 19, and the inlet port 14. Although Fig. 2 shows a schematic diagram, strictly speaking, in the filter medium fused region 52, a portion of the housing 12 (the first sheet portion 20 and the second sheet portion 22) is impregnated with the filter medium 18 and the reinforcing material 19. In the filter medium fused region 52, the outer peripheral surface of the inlet port 14 and the outer peripheral surface of the reinforcing material 19 are surrounded by both the filter medium 18 and the housing 12. Therefore, in the filter medium fused region 52, at the location where the inlet port 14 is located, a portion of the housing 12 is impregnated with the filter medium 18 and the reinforcing material 19, thereby integrally fusion-bonding the housing 12, the filter medium 18, the reinforcing material 19, and the inlet port 14. In the filter medium fused region 52, at a location other than the location where the inlet port 14 is located, a portion of the housing 12 is impregnated with the filter medium 18 and the reinforcing material 19, thereby integrally fusion-bonding the first sheet portion 20, the filter medium 18, the reinforcing material 19, and the second sheet portion 22.

[0070] 1 and 3, the width L3 of the outlet region 42 in the width direction is greater than the width L2 of the filter medium 18 in the width direction (L3>L2). The outlet region 42 extends further toward the outlet port 16 than the tip 38 of the filter medium 18.

[0071] The medical filter 10 according to the first embodiment is used as follows.

[0072] Liquid 49, such as blood, is pumped from outside the housing 12 through the inlet port 14 and flows into the inlet region 40. The filter medium 18 blocks specific components, such as white blood cells, from passing through the liquid 49 that has flowed into the inlet region 40, while allowing components other than the specific components to pass through. After passing through the filter medium 18, the liquid 49 passes through the reinforcing material 19 and flows into the outlet region 42. After flowing into the outlet region 42, the liquid 49 flows out of the housing 12 through the outlet port 16.

[0073] At this time, the filter medium 18 expands in a direction perpendicular to the axial direction of the inlet port 14 under the pressure of the liquid 49. The bottom of the filter medium 18 is pulled up toward the inlet port 14. Since the reinforcing material 19 covers the outer surface of the filter medium 18, the reinforcing material 19 also expands in a direction perpendicular to the axial direction of the inlet port 14 under the pressure of the liquid 49, and the bottom of the reinforcing material 19 is pulled up toward the inlet port 14. At this time, two parallel portions 51 and a tapered portion 53 are formed in the reinforcing material 19. The reinforcing material 19 also has lower extensibility (tensile strength) than the filter medium 18. Therefore, when the liquid 49 passes through the filter medium 18, deformation of the filter medium 18 due to the pressure of the liquid 49 can be suppressed. In other words, the expansion of the filter medium 18 can be suppressed inside the reinforcing material 19. This prevents the filter medium 18 from expanding in a direction perpendicular to the axial direction of the inlet port 14 under the pressure of the liquid 49.

[0074] 10 to 12 show a medical filter 48 according to a comparative example. The medical filter 48 according to the comparative example does not include a reinforcing member 19.

[0075] In the medical filter 48, when a liquid 49 flows into the inflow region 40, the filter medium 18 expands under the pressure of the liquid 49. Specifically, when the liquid 49 flows into the inflow region 40, the filter medium 18 expands under the pressure of the liquid 49 in a direction perpendicular to the axial direction of the inflow port 14, and the bottom of the filter medium 18 is pulled up toward the inflow port 14. This increases the pore size of the filter medium 18, and reduces the filtering performance of the filter medium 18.

[0076] In contrast, in the medical filter 10 according to the first embodiment, the reinforcing material 19 is provided, and therefore the swelling of the filter material 18 is suppressed inside the reinforcing material 19. This suppresses deformation of the filter material 18, and the filtering performance of the filter material 18 can be maintained.

[0077] The first embodiment has the following advantages.

[0078] If the reinforcing member 19 is not provided, when the liquid 49 that has flowed into the inlet region 40 passes through the filter medium 18, the pressure of the liquid 49 may cause the filter medium 18 to deform. Specifically, the pressure of the liquid 49 passing through the filter medium 18 may cause the filter medium 18 to expand in directions perpendicular to the axial direction of the inlet port 14 (the thickness direction and width direction of the housing 12). The expansion of the filter medium 18 may increase the pore size of the porous body that constitutes the filter medium 18, which may reduce the filtering performance of the filter medium 18.

[0079] In contrast, in the first embodiment, as shown in Figures 2 and 3, a reinforcing material 19 is disposed in the internal space 30. The reinforcing material 19 allows the liquid 49 that has passed through the filter medium 18 to pass through, and covers the filter medium 18 in the outflow region 42. Furthermore, when the liquid 49 is passing through, the reinforcing material 19 has a parallel portion 51 and a tapered portion 53 connected to the parallel portion 51. This prevents the filter medium 18 from being deformed by the pressure of the liquid 49 that flows into the inflow region 40 and passes through the filter medium 18. As a result, a decrease in the filtering performance of the filter medium 18 due to deformation of the filter medium 18 can be suppressed.

[0080] The reinforcing material 19 has a lower extensibility than the filter medium 18, and therefore can effectively prevent the filter medium 18 from being deformed by the pressure of the liquid 49 that flows into the inflow region 40 and passes through the filter medium 18.

[0081] The reinforcing material 19 is formed in a bag shape so as to cover the outer surface of the bag-shaped filter medium 18. This allows the filter medium 18 to be easily covered with the reinforcing material 19.

[0082] The base end 36 of the filter medium 18, the inlet port 14, and the base end 37 of the reinforcing member 19 are integrally fixed to the periphery 28 of the housing 12. This allows the filter medium 18, the inlet port 14, and the reinforcing member 19 to be easily fixed inside the housing 12.

[0083] Since the outer surface of the filter medium 18 and the inner surface of the reinforcing material 19 are in contact with each other, deformation of the filter medium 18 due to the pressure of the liquid 49 passing through the filter medium 18 can be effectively prevented.

[0084] By integrally molding the filter material 18 and the reinforcing material 19, the filter material 18 and the reinforcing material 19 can be easily manufactured.

[0085] The parallel portion 51 is parallel to the axial direction of the inlet port 14, and the tapered portion 53 is inclined with respect to the axial direction and is connected to the parallel portion 51 so as to surround the parallel portion 51. This effectively prevents the filter medium 18 from expanding in a direction perpendicular to the axial direction of the inlet port 14 due to the pressure of the liquid 49 when the liquid 49 flows into the inlet region 40.

[0086] The filter medium 18 is a porous body that allows the liquid 49 to pass through, and the reinforcing material 19 is a porous body that has a pore size larger than that of the filter medium 18. This prevents the liquid 49 that has passed through the filter medium 18 from being blocked by the reinforcing material 19.

[0087] If the reinforcing material 19 is a nonwoven fabric, the filter medium 18 can be easily covered with the reinforcing material 19 in the outflow region 42 .

[0088] A medical filter 60 according to a second embodiment will be described with reference to Fig. 13. In the medical filter 60 according to the second embodiment, the same components as those in the medical filter 10 according to the first embodiment (see Figs. 1 to 9) are designated by the same reference numerals, and detailed description thereof will be omitted.

[0089] In the medical filter 60 according to the second embodiment, the filter medium fused region 52 is integrally fused to two side edge portions 62 between the proximal end portion 36 and the distal end portion 38 of the filter medium 18, the proximal end portion 36 of the filter medium 18, and the inflow port 14. Therefore, the filter medium fused region 52 is formed in a U-shape. The filter medium fused region 52 may also be integrally fused to at least one of the two side edge portions 62 of the filter medium 18, the proximal end portion 36 of the filter medium 18, and the inflow port 14.

[0090] The second embodiment also provides the same effects as the first embodiment.

[0091] A medical filter 80 according to a third embodiment will be described with reference to FIGS.

[0092] In the third embodiment, the housing 12 further includes a non-fused region 44 and a window 46 .

[0093] The non-fused region 44 is a space formed inside the housing 12. The non-fused region 44 is a space separate from the internal space 30 of the housing 12. The non-fused region 44 is a spatial region that is not fused. The non-fused region 44 is surrounded by the fused region 32.

[0094] In the third embodiment, only both ends of the filter medium fused region 52 in the width direction are connected to the peripheral fused region 50. In the third embodiment, the filter medium fused region 52 divides the interior of the housing 12 into the internal space 30 and the non-fused region 44. Specifically, the filter medium fused region 52 divides the non-fused region 44 from the outflow region 42 of the internal space 30.

[0095] The non-fused region 44 is formed between the filter media fused region 52 and the fused portion of the peripheral fused region 50 to the inlet port 14. The proximal end 54 of the filter media 18 is located in the non-fused region 44. Specifically, the proximal end 54 of the filter media 18 is located beyond the filter media fused region 52 and in the non-fused region 44.

[0096] Specifically, inlet port 14 is integrally fused to housing 12, sandwiched between peripheral fused region 50 and filter media fused region 52. More specifically, the portion of inlet port 14 located in non-fused region 44 is fused only to proximal end 54 of filter media 18. The portion of inlet port 14 located in non-fused region 44 is not fused to housing 12.

[0097] The non-fused region 44 extends along the width direction of the housing 12. A width L1, which is the dimension of the non-fused region 44 in the width direction, is greater than a width L2 (L1>L2).

[0098] The window portion 46 is a part of the housing 12. The window portion 46 is a part of the first sheet portion 20 and the second sheet portion 22 that constitute the housing 12. The window portion 46 is a window portion for visually observing the non-fused region 44 from outside the housing 12. The window portion 46 is provided in the housing 12 so as to face the non-fused region 44. The window portion 46 is provided in the housing 12 between the non-fused region 44 and the peripheral fused region 50 so as to face the non-fused region 44. Therefore, in the front view of FIG. 14 , the size of the window portion 46 is the same as the size of the non-fused region 44. Therefore, the user can view the base end 54 of the filter medium 18 located in the non-fused region 44 through the window portion 46. As shown in FIG. 15 , the window portion 46 is provided in each of the first sheet portion 20 and the second sheet portion 22 so as to face the non-fused region 44.

[0099] The window portion 46 may be formed in at least one of the first sheet portion 20 and the second sheet portion 22 .

[0100] In the medical filter 80 according to the third embodiment, when the filter medium 18 filters a liquid 49 such as blood, the liquid 49 may pass through portions of the fused region 32 where the fusion bonding strength is low. Such fusion abnormalities are likely to occur at the fusion points between the filter medium fused region 52 and the filter medium 18, and at the fusion points between the filter medium fused region 52, the base end 36 of the filter medium 18, and the inflow port 14. That is, the fusion bonding strength at the fusion points between the filter medium fused region 52 and the filter medium 18 is lower than that at the peripheral fused region 50. Furthermore, because three components, the filter medium fused region 52, the filter medium 18, and the inflow port 14, are fused together, the fusion bonding strength is likely to be lower than that at the peripheral fused region 50.

[0101] Therefore, if the above-described fusion abnormality occurs, the liquid 49 passes through the fused region 52 of the filter medium and flows into the unfused region 44. By visually checking the unfused region 44 through the window 46, the user can confirm whether the liquid 49 has flowed into the unfused region 44. If the user confirms that the liquid 49 has flowed into the unfused region 44, the user can easily recognize that an abnormality has occurred in the medical filter 80.

[0102] The third embodiment also provides the same effects as the first embodiment (see FIGS. 1 to 9). Furthermore, the third embodiment also provides the following effects.

[0103] 14 and 15 , if the liquid 49 flows into the non-fused region 44 when the liquid 49 is introduced into the internal space 30 of the housing 12, a fusion abnormality has occurred inside the medical filter 80. Therefore, by visually checking the inflow of the liquid 49 into the non-fused region 44 from outside the housing 12 through the window 46, an abnormality in the medical filter 80 can be detected early. Furthermore, by detecting an abnormality in the medical filter 80 early, it is possible to reduce loss of the liquid 49 and prevent the liquid 49 from leaking outside the medical filter 80.

[0104] Because the fused filter region 52 is fused to the filter medium 18, the bonding strength due to fusion tends to be weaker than that of the peripheral fused region 50, which is the fused portion between the first sheet portion 20 and the second sheet portion 22. If a fusion abnormality occurs in the fused filter region 52, the liquid 49 will flow into the non-fused region 44. This is effective in early detection of abnormalities in the medical filter 80.

[0105] Because the housing 12, the filter medium 18, and the inlet port 14 are fused together, the fused area between the filter medium fused region 52, the base end 36 of the filter medium 18, and the inlet port 14 is likely to have a lower fusion bonding strength than the peripheral fused region 50. If a fusion defect occurs at the fused area, liquid 49 will flow into the unfused region 44 via the base end 54 of the filter medium 18. The base end 54 of the filter medium 18 is located in the unfused region 44 beyond the filter medium fused region 52. The window 46 faces the unfused region 44. This allows the user to visually check the base end 54 of the filter medium 18 located in the unfused region 44 through the window 46. The user can also easily check through the window 46 whether liquid 49 is flowing into the unfused region 44. This is effective for early detection of abnormalities in the medical filter 80.

[0106] The non-fused region 44 extends along the width direction of the housing 12, and the width L1 of the non-fused region 44 in the width direction is greater than the width L2 of the filter medium 18 in the width direction (L1>L2). This allows the window 46 facing the non-fused region 44 to be larger. As a result, the non-fused region 44 can be easily seen through the window 46 from outside the housing 12.

[0107] The width L3 of the outflow region 42 in the width direction is greater than the width L2 of the filter medium 18 in the width direction (L3>L2). The fused filter region 52 separates the outflow region 42 from the non-fused region 44. If a fusion defect occurs in the fused filter region 52, liquid 49 will flow from the outflow region 42 into the non-fused region 44. This is more effective in early detection of abnormalities in the medical filter 80.

[0108] A medical filter 90 according to a fourth embodiment will be described with reference to FIGS.

[0109] In the medical filter 90 according to the fourth embodiment, the filter medium fused region 52 is integrally fused to two side edge portions 62 between the proximal end portion 36 and the distal end portion 38 of the filter medium 18, the proximal end portion 36 of the filter medium 18, and the inflow port 14. Therefore, as shown in Fig. 16, the filter medium fused region 52 is formed in a U-shape. Note that the filter medium fused region 52 may also be integrally fused to at least one of the two side edge portions 62 of the filter medium 18, the proximal end portion 36 of the filter medium 18, and the inflow port 14.

[0110] In the fourth embodiment, the non-fused region 44 is formed in a U-shape between the filter media fused region 52 and the peripheral fused region 50. The non-fused region 44 has a widthwise portion 64 and two axial portions 66.

[0111] The width direction portion 64 is formed to face the base end portion 36 of the filter medium 18. The width direction portion 64 extends along the width direction. The base end 54 of the filter medium 18 is located in the width direction portion 64. In other words, the base end 54 of the filter medium 18 is located in the width direction portion 64 beyond the filter medium fused region 52.

[0112] Each of the two axial portions 66 is formed to face a side edge portion 62 of the filter medium 18. Each of the two axial portions 66 extends along the axial direction. The side edge 68 of the filter medium 18 is located on the axial portion 66. In other words, the side edge 62 of the filter medium 18 is located on the axial portion 66 beyond the filter medium fused region 52.

[0113] The window 46 is provided in the housing 12 so as to face the non-fused region 44. Therefore, the window 46 is formed in a U-shape. Through the window 46, a user can view the base end 54 and two side edges 62 of the filter medium 18 located in the non-fused region 44. The width L4, which is the dimension of the widthwise portion 64 in the width direction, is greater than the width L2 (L4 > L2). The axial portion 66 also extends further toward the outflow port 16 than the tip end 38 of the filter medium 18.

[0114] The width direction portion 64 and the two axial direction portions 66 may be separated. Furthermore, when the filter medium fused region 52 is integrally fused to one of the two side edge portions 62 of the filter medium 18, the base end portion 36 of the filter medium 18, and the inlet port 14, the filter medium fused region 52 may be formed in an L-shape. In this case, the non-fused region 44 and the window portion 46 are formed in an L-shape corresponding to the filter medium fused region 52.

[0115] The fourth embodiment also provides the same effects as the first embodiment (see FIGS. 1 to 9). Furthermore, the fourth embodiment also provides the following effects.

[0116] As shown in Figures 16 and 17 , because the housing 12, filter medium 18, and inlet port 14 are fused together, the fused portion between the filter medium fused region 52, the base end 36 of the filter medium 18, and the inlet port 14 is likely to have a lower fusion bonding strength than the peripheral fused region 50, which is the fused portion between the first sheet portion 20 and the second sheet portion 22. Furthermore, the fused portions between the filter medium fused region 52, the base end 36, and the side edge 62 of the filter medium 18 are likely to have a lower fusion bonding strength than the peripheral fused region 50. If fusion abnormalities occur at these fused portions, liquid 49 will flow into the unfused region 44 via the base end 54 and side edge 62 of the filter medium 18. The base end 54 and side edge 62 of the filter medium 18 are located beyond the fused region 52 and in the unfused region 44. In other words, the base end 54 and side edge 62 of the filter medium 18 are not fused to the housing 12. The base end 54 and side edge 62 of the filter medium 18 are free ends located within the non-fused region 44. The window 46 faces the non-fused region 44. This allows the user to view the base end 54 and side edge 62 of the filter medium 18 located in the non-fused region 44 through the window 46. The user can also easily check through the window 46 whether liquid 49 has flowed into the non-fused region 44. This is therefore effective for early detection of abnormalities in the medical filter 90.

[0117] The width L4 of the width direction portion 64 in the width direction is greater than the width L2 of the filter medium 18 in the width direction (L4>L2). This allows the portion of the window portion 46 facing the width direction portion 64 to be larger. As a result, the width direction portion 64 can be easily seen through the window portion 46 from outside the housing 12.

[0118] If a fusion defect occurs in the fused region 52 of the filter medium, the liquid 49 will flow from the outflow region 42 into the unfused region 44. This is more effective in early detection of an abnormality in the medical filter 90. In addition, the portion of the window 46 facing the axial portion 66 can be enlarged. This makes it easier to see the axial portion 66 through the window 46 from outside the housing 12.

[0119] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure derived from the content of the claims and their equivalents.

Claims

1. A medical filter comprising: a housing having an internal space; an inlet port fixed to the peripheral edge of the housing and for allowing liquid to flow into the internal space from outside the housing; a filter material fixed to the housing and arranged in the internal space; an outlet port fixed to the peripheral edge and for allowing the liquid that has passed through the filter material to flow out to the outside; and a reinforcing material through which the liquid that has passed through the filter material can pass and which suppresses deformation of the filter material due to the pressure of the liquid passing through the filter material, wherein the filter material divides the internal space into an inlet region where the liquid flows in via the inlet port and an outlet region where the liquid that has passed through the filter material flows out to the outside via the outlet port, and the reinforcing material covers the filter material in the outlet region, and when the liquid is passing through, has a parallel portion and a tapered portion connected to the parallel portion.

2. A medical filter according to claim 1, wherein the reinforcing material has lower extensibility than the filtering material.

3. A medical filter according to claim 1 or 2, wherein the filter material is formed in a bag shape, the interior of the filter material is the inflow area, the inflow port penetrates the base end of the filter material and is inserted into the inflow area, and the reinforcing material is formed in a bag shape so as to cover the outer surface of the filter material.

4. A medical filter according to claim 3, wherein the base end of the filtering material, the inlet port, and the base end of the reinforcing material are integrally fixed to the peripheral edge of the housing.

5. A medical filter according to claim 3, wherein the outer surface of the filtering material and the inner surface of the reinforcing material are in contact with each other.

6. A medical filter according to claim 5, wherein the filtering material and the reinforcing material are integrally formed.

7. A medical filter according to claim 3, wherein the parallel portion is parallel to the axial direction of the inlet port, and the tapered portion is inclined with respect to the axial direction and is connected to the parallel portion so as to surround the parallel portion.

8. A medical filter according to claim 1 or 2, wherein the filter material is a porous material that allows the liquid to pass through, and the reinforcing material is a porous material having a pore size larger than that of the filter material.

9. A medical filter according to claim 8, wherein the reinforcing material is a nonwoven fabric.

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