Medical filter

Abstract

In a medical filter (10), a housing (12) has a fused region (32), a non-fused region (44), and a window (46). The non-fused region (44) is a space different from an internal space (30) inside the housing (12). The non-fused region (44) is a region that is not fused. The non-fused region (44) is surrounded by the fused region (32). The window (46) is provided to the housing (12) in order to visually confirm the non-fused region (44) from outside of the housing (12).

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 includes a housing, an inlet port, an outlet port, and a filter material. The housing is formed by fusing the outer edges of two flexible sheets. The inlet port and the outlet port are each fused to the periphery of the housing. The filter material is fused to the housing and disposed within the housing's interior space. The filter material divides the housing's interior space 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 a specific component (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 via the outlet port.

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

[0004] There is a need for early detection of fusion abnormalities (fusion abnormalities) in medical filters.

[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 formed by fusing the outer edge of a first sheet portion and the outer edge of a second sheet portion; an inlet port fused to the peripheral edge of the housing for allowing liquid to flow from the outside of the housing into the internal space of the housing; a filter material fused to the housing and disposed in the internal space; and an outlet port fused to the peripheral edge for allowing the liquid that has passed through the filter material to flow out to the outside, wherein the filter material divides the internal space into an inlet region into which the liquid flows in via the inlet port and an outlet region from which the liquid that has passed through the filter material flows out to the outside via the outlet port, and the housing has a non-fused region that is a space separate from the internal space, is an unfused region, and is surrounded by the fused region, and a window portion for visually viewing the non-fused region from the outside.

[0007] With this configuration, if liquid flows into the unfused region when introduced into the internal space of the housing, a fusion defect has occurred inside the medical filter. Therefore, by visually checking the inflow of liquid into the unfused region from outside the housing through the window, an abnormality in the medical filter can be detected early. Furthermore, by detecting an abnormality in the medical filter early, it is possible to reduce liquid loss and prevent liquid from leaking outside the medical filter.

[0008] (2) In the medical filter described in (1) above, the filter material is formed in a bag shape, the inside of the filter material is the inflow region, the fused region includes a peripheral fused region that fuses the peripheral portion and a filter material fused region that is fused to the filter material, and the filter material fused region may divide the inside of the housing into the internal space and the non-fused region.

[0009] The fused region of the filter media is fused to the filter media, and therefore tends to have a weaker bonding strength than the peripheral fused region, which is the fused portion between the first and second sheet portions. If a fusion defect occurs in the fused region of the filter media, liquid will flow into the non-fused region. This is effective for early detection of abnormalities in medical filters.

[0010] (3) In the medical filter described in (2) above, the inlet port may be inserted into the inlet region through the base end of the filter material, the filter material fused region may be integrally fused to the base end of the filter material and the inlet port, the non-fused region may be formed between the filter material fused region and the peripheral fused region, the base end of the filter material may be located in the non-fused region, and the window portion may be provided in the housing so as to face the non-fused region.

[0011] Because the housing, filter medium, and inlet port are fused together, the fused area between the filter medium fused region, the base end of the filter medium, and the inlet port is likely to have a lower bonding strength due to fusion than the peripheral fused area. If a fusion abnormality occurs at the fused area, liquid will flow into the non-fused area via the base end of the filter medium. The base end of the filter medium is located in the non-fused area beyond the filter medium fused region. The window also faces the non-fused area. This allows the user to visually check the base end of the filter medium located in the non-fused area through the window. Furthermore, the user can easily check through the window whether liquid is flowing into the non-fused area. This is therefore effective for early detection of abnormalities in medical filters.

[0012] (4) In the medical filter described in (3) above, the non-fused region may extend along the width direction of the housing, which is perpendicular to the thickness direction of the housing and the axial direction of the inlet port, and the width of the non-fused region in the width direction may be greater than the width of the filter material in the width direction.

[0013] This configuration allows the window portion facing the non-fused region to be enlarged, making it easier to see the non-fused region through the window portion from outside the housing.

[0014] (5) In the medical filter described in (4) above, the width of the outflow region in the width direction may be greater than the width of the filter material in the width direction, and the filter material fused region may separate the non-fused region and the outflow region.

[0015] If a fusion defect occurs in the fused region of the filter medium, liquid will flow from the outflow region into the non-fused region, which is more effective in early detection of defects in medical filters.

[0016] (6) In the medical filter described in (2) above, the inlet port is inserted into the inlet region through the base end of the filter material, the filter material fused region is integrally fused to at least one of the two side edge portions of the filter material between the base end and the tip end of the filter material, the base end, and the inlet port, the non-fused region is formed between the filter material fused region and the peripheral fused region, and has a width direction portion extending along the width direction of the housing perpendicular to the thickness direction of the housing and the axial direction of the inlet port, and an axial direction portion extending along the axial direction, the base end of the filter material is located in the width direction portion, and the side edge of at least one of the side edge portions is located in the axial direction portion, and the window portion may be provided in the housing so as to face the non-fused region.

[0017] Because the housing, filter medium, and inlet port are fused together, the fused area between the filter medium fused region, the base end of the filter medium, and the inlet port is likely to have a lower fusion bonding strength than the peripheral fused area, which is the fused area between the first sheet portion and the second sheet portion. Furthermore, because the filter medium fused region is fused to the filter medium, the fused area between the filter medium fused region, the base end, and side edges of the filter medium is likely to have a lower fusion bonding strength than the peripheral fused area. If fusion abnormalities occur at these fused areas, liquid will flow into the non-fused area through the base end and side edges of the filter medium. The base end and side edges of the filter medium are located in the non-fused area beyond the filter medium fused region. Furthermore, the window portion faces the non-fused area. Therefore, the user can visually check the base end and side edges of the filter medium located in the non-fused area through the window portion. Furthermore, the user can easily check through the window portion whether liquid is flowing into the non-fused area. Therefore, it is effective in early detection of abnormalities in medical filters.

[0018] (7) In the medical filter described in (6) above, the width of the width direction portion in the width direction may be greater than the width of the filter medium in the width direction.

[0019] The portion of the window that faces the width direction portion can be enlarged, which makes it easier to see the width direction portion through the window portion from outside the housing.

[0020] (8) In the medical filter described in (7) above, the axial portion may extend further toward the outflow port than the tip portion, the outflow region may extend further toward the outflow port than the tip portion, and the filter material fused region may separate the non-fused region and the outflow region.

[0021] If a fusion defect occurs in the fused region of the filter media, liquid will flow from the outflow region into the unfused region. This is more effective for early detection of defects in medical filters. Furthermore, the portion of the window facing the axial portion can be enlarged. This makes it easier to see the axial portion through the window from outside the housing.

[0022] According to the present invention, if liquid flows into the unfused region when introduced into the internal space of the housing, a fusion defect has occurred inside the medical filter. Therefore, by visually checking the inflow of liquid into the unfused region from outside the housing through the window, an abnormality in the medical filter can be detected early. Furthermore, by detecting an abnormality in the medical filter early, it is possible to reduce liquid loss and prevent liquid from leaking outside the medical filter.

[0023] 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 configuration examples of the filter medium. FIG. 5 is a front view of a medical filter according to a second embodiment. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a front view of a medical filter according to a third embodiment.

[0024] A medical filter 10 according to a first embodiment will be described with reference to Figures 1 to 3. The medical filter 10 is a filter for filtering a liquid. The medical filter 10 is a filter for preventing the passage of a predetermined component in the liquid. The medical filter 10 can be a filter for preventing the passage of a predetermined component in blood (e.g., white blood cells).

[0025] The medical filter 10 includes a housing 12 , an inlet port 14 , an outlet port 16 , and a filter media 18 .

[0026] 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. As shown in FIGS. 1 and 2 , 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 styrene-isoprene-styrene copolymer, and mixtures of thermoplastic elastomers with softeners such as polyolefins and ethylene-ethyl acrylate.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] As shown in Figures 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 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, such as blood, to flow from the outside of the housing 12 into the internal space 30 of the housing 12.

[0031] 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 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 in the internal space 30 of the housing 12 to flow out of the housing 12.

[0032] The inlet port 14 and the outlet port 16 are fused to the housing 12 while facing each other. That is, the inlet port 14 and the outlet port 16 are fused coaxially to the housing 12. The inlet port 14 and the outlet port 16 are disposed on the central axis 34 of the inlet port 14.

[0033] 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. As shown in FIG. 1 , the filter medium 18 is fused 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.

[0034] 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 elastomer.

[0035] 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.

[0036] The filter media 18 may be formed as shown in Figures 4A and 4B.

[0037] 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.

[0038] 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.

[0039] 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 communicates 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.

[0040] 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. Liquid flows into the inlet region 40 via the inlet port 14.

[0041] The filter medium 18 prevents passage of predetermined components (e.g., white blood cells in blood) in the liquid that has flowed into the inflow region 40. The filter medium 18 allows passage of components other than the predetermined components in the liquid.

[0042] The outflow region 42 is a space outside the filter medium 18 within the interior space 30 of the housing 12. The outflow region 42 is connected to the outlet port 16. Liquid that has passed through the filter medium 18 flows into the outflow region 42. The liquid that has flowed into the outflow region 42 flows out of the housing 12 via the outlet port 16.

[0043] The housing 12 further includes a fused region 32 , an unfused region 44 , and a window 46 .

[0044] 1 to 3, 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.

[0045] Fused region 32 includes a peripheral fused region 50 and a filter media fused region 52 .

[0046] 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.

[0047] The peripheral fused region 50 is integrally fused to the inlet port 14 and outlet port 16 .

[0048] Inflow port 14 is integrally fused to housing 12, sandwiched between peripheral fused region 50 and filter media fused region 52. Specifically, the portion of inflow port 14 located in non-fused region 44 is fused only to base end 54 of filter media 18. The portion of inflow port 14 located in non-fused region 44 is not fused to housing 12.

[0049] 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.

[0050] 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. The filter medium fused region 52 is formed more inward in the width direction of the housing 12 than the peripheral fused region 50.

[0051] As shown in FIG. 1 , both ends of the filter medium fused region 52 in the width direction are connected to the peripheral fused region 50. As shown in FIGS. 1 and 2 , 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. The filter medium fused region 52 is integrally fused to the base end 36 of the filter medium 18 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. In the filter medium fused region 52, the outer peripheral surface of the inlet port 14 is 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, thereby fusion-bonding the housing 12, the filter medium 18, and the inlet port 14 together. 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, thereby fusion-bonding the first sheet portion 20, the filter medium 18, and the second sheet portion 22 together.

[0052] 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.

[0053] 1 and 3, the non-fused region 44 extends along the width direction of the housing 12. 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). 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 outflow region 42 extends further toward the outflow port 16 than the tip 38 of the filter medium 18.

[0054] As shown in FIGS. 1 to 3 , the window 46 is a part of the housing 12. The window 46 is a part of the first sheet portion 20 and the second sheet portion 22 that constitute the housing 12. The window 46 is a window portion that allows the non-fused region 44 to be viewed from outside the housing 12. The window 46 is provided in the housing 12 so as to face the non-fused region 44. The window 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. 1 , the size of the window 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 46. As shown in FIGS. 2 and 3 , the window 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.

[0055] The window portion 46 may be formed in at least one of the first sheet portion 20 and the second sheet portion 22 .

[0056] The medical filter 10 according to the first embodiment is used as follows.

[0057] Liquid such as blood flows into the inlet region 40 from outside the housing 12 via the inlet port 14. The filter medium 18 blocks the passage of certain components, such as white blood cells, while allowing components other than the certain components to pass through. The liquid that passes through the filter medium 18 flows into the outlet region 42. The liquid that flows into the outlet region 42 flows out of the housing 12 via the outlet port 16.

[0058] At this time, there is a possibility that liquid may pass through portions of the fused region 32 where the bonding strength due to fusion 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 inlet port 14. That is, the fusion strength at the fusion points between the filter medium fused region 52 and the filter medium 18 is lower than that of the peripheral fused region 50. Furthermore, because three components, the filter medium fused region 52, the filter medium 18, and the inlet port 14, are fused together, the bonding strength due to fusion is likely to be lower than that of the peripheral fused region 50.

[0059] Therefore, if the above-described fusion abnormality occurs, liquid will pass through the fused region 52 of the filter medium and flow into the unfused region 44. By visually checking the unfused region 44 through the window 46, the user can confirm whether liquid has flowed into the unfused region 44. If the user confirms that liquid has flowed into the unfused region 44, they can easily recognize that an abnormality has occurred in the medical filter 10.

[0060] The first embodiment has the following advantages.

[0061] 1 to 3, if liquid flows into the non-fused region 44 when introduced into the internal space 30 of the housing 12, a fusion abnormality has occurred inside the medical filter 10. Therefore, by visually checking the inflow of liquid into the non-fused region 44 from outside the housing 12 through the window 46, an abnormality in the medical filter 10 can be detected early. Furthermore, by detecting an abnormality in the medical filter 10 early, it is possible to reduce liquid loss and prevent liquid from leaking outside the medical filter 10.

[0062] 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 defect occurs in the fused filter region 52, liquid will flow into the non-fused region 44. This is effective in early detection of abnormalities in the medical filter 10.

[0063] 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 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 is flowing into the unfused region 44. This is therefore effective for early detection of abnormalities in the medical filter 10.

[0064] 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.

[0065] 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 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 10.

[0066] A medical filter 60 according to a second embodiment will be described with reference to Figures 5 and 6. 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 Figures 1 to 4B) are designated by the same reference numerals, and detailed description thereof will be omitted.

[0067] 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, as shown in Fig. 5, 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.

[0068] In the second 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.

[0069] 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.

[0070] 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.

[0071] 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 edge portions 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 of the filter medium 18 in the width direction (L4 > L2). Furthermore, the axial portion 66 extends further toward the outflow port 16 than the tip end 38 of the filter medium 18.

[0072] 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.

[0073] The second embodiment has the following advantages.

[0074] As shown in Figures 5 and 6, 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 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 unfused region 44. The window 46 faces the unfused region 44. This allows the user to view the base end 54 and side edge 62 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 has flowed into the unfused region 44. This is therefore effective for early detection of abnormalities in the medical filter 60.

[0075] 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.

[0076] If a fusion defect occurs in the fused region 52 of the filter medium, liquid 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 60. 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.

[0077] A medical filter 70 according to a third embodiment will be described with reference to FIG.

[0078] In the medical filter 70 according to the third embodiment, the filter medium fused region 52 is integrally fused to the base end 36 and two side edge portions 62 of the filter medium 18 and to the inflow port 14. Therefore, the filter medium fused region 52 is formed in a U-shape. As shown in Fig. 7 , the width L2 of the filter medium 18 is greater than the width L1 of the non-fused region 44 (L2 > L1). 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 base end 36 of the filter medium 18, and the inflow port 14.

[0079] The third embodiment also provides the same effects as the first embodiment.

[0080] 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 formed by fusing the outer edge of a first sheet portion and the outer edge of a second sheet portion; an inlet port fused to the peripheral edge of the housing for allowing liquid to flow into the interior space of the housing from outside; a filter material fused to the housing and disposed in the interior space; and an outlet port fused to the peripheral edge for allowing the liquid that has passed through the filter material to flow out to the outside, wherein the filter material divides the interior space into an inlet region into which the liquid flows in via the inlet port and an outlet region from which the liquid that has passed through the filter material flows out to the outside via the outlet port, and the housing has: a non-fused region that is a space separate from the interior space, is not fused, and is surrounded by the fused region; and a window portion for allowing the non-fused region to be viewed from the outside.

2. A medical filter according to claim 1, wherein the filter material is formed in a bag shape, the interior of the filter material is the inflow region, the fused region includes a peripheral fused region that fuses the peripheral portion and a filter material fused region that is fused to the filter material, and the filter material fused region divides the interior of the housing into the internal space and the non-fused region.

3. A medical filter according to claim 2, wherein the inlet port penetrates the base end of the filter material and is inserted into the inlet region, the filter material fused region is integrally fused to the base end of the filter material and the inlet port, the non-fused region is formed between the filter material fused region and the peripheral fused region, the base end of the filter material is located in the non-fused region, and the window portion is provided in the housing so as to face the non-fused region.

4. A medical filter according to claim 3, wherein the non-fused region extends along the width direction of the housing, which is perpendicular to the thickness direction of the housing and the axial direction of the inlet port, and the width of the non-fused region in the width direction is greater than the width of the filter material in the width direction.

5. A medical filter according to claim 4, wherein the width of the outflow region in the width direction is greater than the width of the filter material in the width direction, and the fused region of the filter material separates the non-fused region from the outflow region.

6. A medical filter according to claim 2, wherein the inlet port penetrates the base end of the filter material and is inserted into the inlet region; the filter material fused region is integrally fused to at least one of two side edge portions of the filter material between the base end and the tip end of the filter material, to the base end, and to the inlet port; the non-fused region is formed between the filter material fused region and the peripheral fused region and has: a width direction portion extending along the width direction of the housing which is perpendicular to the thickness direction of the housing and the axial direction of the inlet port; and an axial direction portion extending along the axial direction; the base end of the filter material is located in the width direction portion; a side edge of at least one of the side edge portions is located in the axial direction portion; and the window portion is provided in the housing so as to face the non-fused region.

7. A medical filter according to claim 6, wherein the width of the width direction portion in the width direction is greater than the width of the filter material in the width direction.

8. A medical filter according to claim 7, wherein the axial portion extends further toward the outflow port than the tip portion, the outflow region extends further toward the outflow port than the tip portion, and the fused region of the filter medium separates the non-fused region from the outflow region.

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