Medical filters

Abstract

The housing 12 of the medical filter 10 has a second housing 12B that forms a liquid outflow chamber 18 between itself and the filter material 14. The second housing 12B has a liquid chamber forming surface 54 that forms the liquid outflow chamber 18 between itself and the filter material 14, a groove-shaped guide channel 60, an outflow recess 64 recessed relative to the guide channel 60, and an outflow channel 66 communicating with the outflow recess 64. At least one of the first dimension S1 of the outflow recess 64 in the first direction (Z direction) and the second dimension S2 of the outflow recess 64 in the thickness direction (X direction) and the second direction (Y direction) perpendicular to the first direction is greater than the channel diameter 66d at the upstream end of the outflow channel 66.

Description

[Technical Field]

[0001] The present disclosure relates to a medical filter. [Background Art]

[0002] Medical filters for removing a part of blood components in the production of blood products are known. As one type of medical filter, for example, Japanese Patent No. 2555722 discloses a leukocyte removal filter. [Prior Art Literature] [Patent Literature]

[0003] [Patent Literature 1] Japanese Patent No. 2555722 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In medical filters, it is desirable to improve filtration efficiency.

[0005] An object of the present disclosure is to solve the above-mentioned problems. [Means for Solving the Problem]

[0006] (1) An aspect of the present disclosure is a medical filter comprising a hollow housing and a sheet-like filter material disposed within the housing and dividing the housing into a liquid inlet chamber and a liquid outlet chamber, wherein the housing has a first housing that forms the liquid inlet chamber with respect to the filter material and a second housing that forms the liquid outlet chamber with respect to the filter material, the filter material is sandwiched between the first housing and the second housing, and the second housing has a liquid chamber forming surface that faces the filter material and forms the liquid outlet chamber with respect to the filter material and the liquid chamber A medical filter comprising: a groove-shaped guide channel having an outflow opening at one end that opens on the forming surface, recessed in the liquid chamber forming surface and extending in a first direction perpendicular to the thickness direction of the filter material; an outflow recess communicating with the guide channel and recessed relative to the guide channel; and an outflow channel communicating with the outflow recess and extending in a direction intersecting the recess direction of the outflow recess, wherein at least one of the first dimension of the outflow recess in the first direction and the second dimension of the outflow recess in the second direction perpendicular to the thickness direction and the first direction is larger than the channel diameter at the upstream end of the outflow channel.

[0007] With this configuration, at least one of the first and second dimensions of the outflow recess is larger than the flow channel diameter at the upstream end of the outflow channel, allowing the liquid to flow efficiently from the liquid outflow chamber through the outflow opening into the outflow channel. This improves filtration efficiency.

[0008] (2) In the medical filter described in item (1) above, the second housing is provided with a plurality of outlet-side ribs that protrude toward the filter material and extend along the peripheral shape of the second housing, and when viewed from the thickness direction, the plurality of outlet-side ribs are spaced apart from the center outward of the second housing, and the liquid outlet chamber may be divided by the plurality of outlet-side ribs into a plurality of outlet compartments that communicate with the outlet opening.

[0009] With this configuration, the liquid that has passed through multiple outlet compartments can be efficiently flowed into the outlet opening.

[0010] (3) In the medical filter described in item (2) above, the liquid chamber forming surface may be curved in a concave shape so as to be furthest from the filter material at the center in the second direction.

[0011] This configuration allows for efficient distribution of liquid to the central outflow section, improving the efficiency of filter media usage.

[0012] (4) In the medical filter described in item (3) above, the protrusion length of the centrally located outflow rib from the liquid chamber forming surface may be greater than the protrusion lengths of the other outflow ribs.

[0013] With this configuration, the thickness of the outlet section located closest to the center can be maximized among the multiple outlet sections.

[0014] (5) In a medical filter according to any one of the above items (1) to (4), the second housing has an outlet tube insertion hole into which an outlet tube is inserted, and the outlet tube insertion hole has a first tapered hole opening to the outer surface of the second housing and a second tapered hole formed between the first tapered hole and the outlet channel, and the taper angle of the first tapered hole may be greater than the taper angle of the second tapered hole.

[0015] This configuration improves work efficiency when inserting the outflow tube into the outflow tube insertion hole during the assembly process of medical filters.

[0016] (6) In the medical filter described in item (5) above, the second housing has a housing body on which the liquid chamber forming surface is formed, and a protruding portion that protrudes from the housing body in the thickness direction, the outflow channel and the outflow tube insertion hole are formed inside the protruding portion, and a cavity may be formed between the outflow tube insertion hole and the housing body.

[0017] According to such a configuration, it is possible to suppress the shape error of the outlet tube insertion hole caused by the influence of sink marks when the second housing is molded by injection molding. In addition, it is easy to identify that the housing is the second housing during the assembly work of the medical filter, which contributes to the improvement of work efficiency. [Effects of the Invention]

[0018] According to the medical filter of the present disclosure, since at least one of the first dimension and the second dimension of the outlet recess is larger than the flow path diameter of the upstream end of the outlet flow path, liquid can be efficiently caused to flow from the liquid outlet chamber to the outlet flow path through the outlet opening. Thereby, the filtration efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [Figure 1] FIG. 1 is a schematic diagram of a medical bag system to which a medical filter according to an embodiment of the present disclosure is applied. [Figure 2] FIG. 2 is an exploded perspective view of the medical filter. [Figure 3] FIG. 3 is a longitudinal cross-sectional view of the medical filter. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5] FIG. 5 is a configuration explanatory diagram of a first housing. [Figure 6] FIG. 6 is a configuration explanatory diagram of a second housing. MODE FOR CARRYING OUT THE INVENTION

[0020] As shown in FIG. 1, the medical filter 10 according to the present embodiment can be applied to, for example, a medical bag system 100. The medical bag system 100 is used for transferring platelets (platelet-containing liquid) stored in a plurality of platelet bags 102 to a pooling bag 104 after removing leukocytes. Therefore, in the present embodiment, the medical filter 10 is configured as a leukocyte removal filter. Hereinafter, a case where the liquid to be filtered is a platelet-containing liquid will be described as an example.

[0021] An inflow tube 106 and an outflow tube 108 are connected to the medical filter 10. A plurality of branched branch tubes 110 are connected to the upstream side of the inflow tube 106. A platelet bag 102 is connected to each of the branch tubes 110. The medical filter 10 is connected to the downstream end of the inflow tube 106. The medical filter 10 is connected to the upstream end of the outflow tube 108. A pooling bag 104 is connected to the downstream end of the outflow tube 108.

[0022] The platelet-containing liquid flowing out from the platelet bag 102 flows into the medical filter 10 via the branch tubes 110 and the inflow tube 106. After leukocytes are removed from the platelet-containing liquid that has flowed into the medical filter 10, the liquid flows into the pooling bag 104 via the outflow tube 108. As a result, the leukocyte-removed platelet-containing liquid (concentrated platelets) is stored in the pooling bag 104. A leukocyte-removed platelet preparation is obtained in this manner.

[0023] As shown in Figure 2, the medical filter 10 includes a housing 12 and a filter medium 14. The medical filter 10 has a generally flat shape as a whole. In the following description, the thickness direction of each of the housing 12 and the filter medium 14 is synonymous with the thickness direction (X direction) of the medical filter 10. The medical filter 10 is relatively long in a first direction (Z direction) which is one direction orthogonal to the thickness direction thereof, and relatively short in a second direction (Y direction) which is orthogonal to both the thickness direction and the first direction. Hereinafter, with respect to the medical filter 10 and the constituent elements thereof, the first direction is also referred to as "longitudinal direction" or "axial direction", and the second direction is also referred to as "transverse direction" or "width direction".

[0024] The medical filter 10 is used with the first direction aligned along the direction of gravity. Therefore, in the following description, the medical filter 10 and the constituent elements thereof will be explained with reference to the orientation thereof during use.

[0025] The housing 12 has dimensions in the first direction that are greater than its dimensions in the second direction. The housing 12 is formed with an arc shape at the top and bottom, and straight lines on both sides in the width direction. That is, the housing 12 has an oval shape. As shown in Figure 3, the housing 12 is formed in a hollow shape. The internal space of the housing 12 is divided into a liquid inlet chamber 16 and a liquid outlet chamber 18 by the filter material 14. The housing 12 consists of a first housing 12A and a second housing 12B.

[0026] The first housing 12A and the second housing 12B are made of, for example, a rigid resin. Examples of such materials include polyesters and polyamides such as polyvinyl chloride, polyethylene, polypropylene, cyclic polyolefin, polystyrene, polycarbonate, acrylic resin, polyethylene terephthalate, PETG (Glycol-modified PET), polyethylene naphthalate, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene copolymer (ABS resin), and acrylonitrile-styrene copolymer (AS resin).

[0027] The first housing 12A is a component that forms a liquid inflow chamber 16 between itself and the filter material 14. The first housing 12A has an inflow tube insertion hole 20, an inflow channel 22, an inflow recess 24, an inflow opening 26, a liquid chamber forming surface 27, a first pressing rib 28, and at least one inflow-side rib 30. Hereinafter, the liquid chamber forming surface 27 will be referred to as the "first liquid chamber forming surface 27".

[0028] The inlet tube insertion hole 20 is a hole into which the inlet tube 106 is inserted. The inlet tube 106 is joined to the inlet tube insertion hole 20, for example, by adhesive. The inlet tube insertion hole 20 is formed in the first projection 34 of the first housing 12A. The first projection 34 is a portion of the first housing 12A that protrudes from the first housing body 32 in the X1 direction. The first projection 34 extends in the Z direction. The first housing body 32 is a portion of the first housing 12A that forms a liquid inlet chamber 16 between itself and the filter material 14.

[0029] The inlet tube insertion hole 20 has a first tapered hole 20A and a second tapered hole 20B. The first tapered hole 20A opens onto the outer surface of the first housing 12A (the upper end surface of the first protrusion 34). The first tapered hole 20A constitutes the upper part of the inlet tube insertion hole 20. The first tapered hole 20A tapers downwards. In the assembly process, the first tapered hole 20A functions as a guide hole when inserting the inlet tube 106 into the inlet tube insertion hole 20.

[0030] The second tapered hole 20B is formed between the first tapered hole 20A and the inflow channel 22. The upper end of the second tapered hole 20B is connected to the lower end of the first tapered hole 20A. The second tapered hole 20B decreases in diameter downwards. The second tapered hole 20B is longer than the first tapered hole 20A. The taper angle of the first tapered hole 20A is greater than the taper angle of the second tapered hole 20B.

[0031] The inflow channel 22 transfers the liquid to the inflow recess 24. The inflow channel 22 is formed in the first projection 34 below the inflow tube insertion hole 20. The inflow channel 22 protrudes downward from the lower end of the inflow tube insertion hole 20 and extends in the first direction (Z direction). The inflow channel 22 has a smaller diameter than the lower end of the second tapered hole 20B. The inflow channel 22 is formed such that its channel diameter decreases from the upstream end to the downstream end.

[0032] The inlet recess 24 communicates with the inlet channel 22. The cross-sectional shape of the inlet channel 22 is circular, and it opens in a circular shape on the surface communicating with the inlet recess 24 (the surface intersecting with the inlet opening 26). The inlet recess 24 is connected to the downstream end of the inlet channel 22. The inlet recess 24 is a groove recessed relative to the first liquid chamber forming surface 27. The length of the inlet recess 24 in the extending direction (Z direction) of the inlet channel 22 is greater than the channel diameter at the downstream end of the inlet channel 22.

[0033] The inlet opening 26 is one end of the inlet recess 24. The inlet opening 26 is located at the bottom of the housing 12 when the medical filter 10 is in use. The inlet opening 26 communicates with the inlet channel 22 and the liquid inlet chamber 16 and faces the filter material 14 and the liquid inlet chamber 16. The inlet opening 26 opens at the first liquid chamber forming surface 27.

[0034] As shown in Figure 5, the opening width (Y-direction dimension) of the inlet opening 26, when viewed along the thickness direction, increases towards the outer edge of the first housing 12A. That is, the opening width of the inlet opening 26 increases downwards. For this reason, the inlet opening 26 is formed in a fan shape or trapezoidal shape. In the width direction (Y-direction) of the first housing 12A, the lower side 26b of the inlet opening 26 is longer than the upper side 26a. The pair of side sides 26c and 26d connecting the upper side 26a and the lower side 26b of the inlet opening 26 are inclined with respect to the axis Ax of the housing 12.

[0035] As shown in Figure 4, the first liquid chamber forming surface 27 is the surface in the first housing 12A that faces the filter material 14. The first liquid chamber forming surface 27 is the inner surface of the first housing body 32. The first liquid chamber forming surface 27 is curved concavely with respect to the filter material 14 so that it is furthest from the filter material 14 at its center in the width direction. In this embodiment, the first liquid chamber forming surface 27 is curved in an arc shape. The outer surface (hereinafter referred to as the "first outer surface 32S") on the opposite side of the first liquid chamber forming surface 27 in the first housing body 32 is also curved in an arc shape. Therefore, the wall portion 32W of the first housing body 32 is an arc-shaped curved wall. The radius of curvature of the first outer surface 32S is larger than the radius of curvature of the first liquid chamber forming surface 27.

[0036] As shown in Figure 5, the first pressing rib 28 is formed adjacent to the inside of the peripheral wall portion 32P of the first housing body 32 and follows the peripheral shape of the first housing body 32. Therefore, when viewed from the thickness direction of the housing 12, the first pressing rib 28 has an oval shape. The first pressing rib 28 is a rib that extends continuously around the entire circumference. The first pressing rib 28 presses against the peripheral edge of the filter material 14.

[0037] The liquid inlet chamber 16 is divided into a plurality of inlet compartments 46 that communicate with the inlet opening 26 by at least one inlet-side rib 30. In this embodiment, the first housing 12A is provided with a plurality of inlet-side ribs 30 (30a to 30c) (three in the illustrated example) spaced apart from the center of the first housing 12A outward. When viewed from the thickness direction of the housing 12, each inlet-side rib 30 has an oval shape.

[0038] Multiple inlet ribs 30 are formed inside the first pressing rib 28. The multiple inlet ribs 30 are spaced apart from the center of the first housing 12A outward. Each inlet rib 30 extends along the peripheral shape of the first housing 12A. As shown in Figure 4, the inlet ribs 30 protrude toward the filter media 14. The tip of each inlet rib 30 is in contact with the filter media 14.

[0039] As shown in Figure 5, each inlet rib 30 has an upper arc portion 38, a pair of straight portions 40, and a lower arc portion 42. The upper arc portion 38 extends in an arc shape along the upper arc shape of the first housing 12A. The pair of straight portions 40 extend parallel to each other along the axis Ax. The lower arc portion 42 extends in an arc shape along the lower arc shape of the first housing 12A. A notch 44 is formed in the widthwise center of the lower arc portion 42. Therefore, each inlet rib 30 has both ends formed by the notch 44. The multiple notches 44 formed in the lower arc portions 42 are arranged in a straight line along the axis Ax.

[0040] An inlet opening 26 is provided between the two ends of the outermost inlet rib 30c in the direction of extension. Therefore, the upper edge 26a of the inlet opening 26 is located above the notch 44 of the outermost inlet rib 30c. The lower edge 26b of the inlet opening 26 is located below the notch 44 of the outermost inlet rib 30c.

[0041] As shown in Figure 4, among the multiple inlet ribs 30, the protrusion length from the first liquid chamber forming surface 27 of the inlet rib 30a located closest to the center is greater than the protrusion lengths of the other inlet ribs 30b and 30c. On the other hand, the heights of the multiple inlet ribs 30 in the first housing 12A are the same. That is, the protrusions of the multiple inlet ribs 30 lie on a single straight line parallel to the width direction.

[0042] As shown in Figure 5, when viewed from the thickness direction, the multiple inlet compartments 46 are arranged in parallel from the center outward of the first housing 12A. The inlet compartment 46a located furthest in the center of the multiple inlet compartments 46 extends in the first direction (axial direction / Z direction). The width W1 of the innermost inlet compartment 46 is greater than the width W2 of the other inlet compartments 46.

[0043] As shown in Figure 4, the thickness (dimension in the X direction) of the multiple inflow compartments 46 increases as they move towards the center in the width direction (Y direction). Therefore, among the multiple inflow compartments 46, the inflow compartment 46a located in the center has the maximum thickness, and the inflow compartment 46d located on the outermost side has the minimum thickness.

[0044] The second housing 12B is a component that forms a liquid outflow chamber 18 between itself and the filter material 14. The second housing 12B has a housing body 50 and a protrusion 52. Hereinafter, the housing body 50 will be referred to as the "second housing body 50," and the protrusion 52 will be referred to as the "second protrusion 52." As shown in Figure 3, the second protrusion 52 protrudes from the second housing body 50 in the thickness direction (X2 direction) and extends in the axial direction (Z direction).

[0045] The second housing 12B has an internal structure comprising a liquid chamber forming surface 54, a second pressing rib 56, at least one outlet side rib 58, a guide channel 60, an outlet opening 62, an outlet recess 64, an outlet channel 66, and an outlet tube insertion hole 68. Hereinafter, the liquid chamber forming surface 54 will be referred to as the "second liquid chamber forming surface 54".

[0046] The second liquid chamber forming surface 54 is the surface in the second housing 12B that faces the filter material 14. The second liquid chamber forming surface 54 is the inner surface of the second housing body 50. The second liquid chamber forming surface 54 forms a liquid outflow chamber 18 with the filter material 14.

[0047] As shown in Figure 4, the second liquid chamber forming surface 54 is curved concavely with respect to the filter material 14 so that it is furthest from the filter material 14 in the center in the width direction. In this embodiment, the second liquid chamber forming surface 54 is curved in an arc shape. The outer surface of the second housing body 50, which is the surface opposite to the second liquid chamber forming surface 54 (hereinafter referred to as the "second outer surface 50S"), is also curved in an arc shape. Therefore, the wall portion 50W of the second housing body 50 is an arc-shaped curved wall. The radius of curvature of the second outer surface 50S is larger than the radius of curvature of the second liquid chamber forming surface 54.

[0048] As shown in Figure 6, the second pressing rib 56 is formed adjacent to the inner side of the outer peripheral edge of the second housing body 50 and follows the peripheral shape of the second housing body 50. Therefore, when viewed from the thickness direction of the housing 12, the second pressing rib 56 has an oval shape. The second pressing rib 56 is a rib that extends continuously around the entire circumference. The second pressing rib 56 presses against the peripheral edge of the filter material 14.

[0049] The liquid outlet chamber 18 is divided into multiple outlet compartments 70 by at least one outlet-side rib 58. In this embodiment, the second housing 12B is provided with multiple (three in the illustrated example) outlet-side ribs 58 (58a to 58c) spaced apart from the center of the second housing 12B outward. Viewed from the thickness direction of the housing 12, each outlet-side rib 58 has an oval shape.

[0050] Multiple outlet ribs 58 are formed inside the second pressing rib 56. Each outlet rib 58 extends along the peripheral shape of the second housing 12B. As shown in Figure 4, each outlet rib 58 protrudes toward the filter media 14. The tip of each outlet rib 58 is in contact with the filter media 14.

[0051] As shown in Figure 6, each outflow rib 58 has an upper arc portion 72, a pair of straight portions 74, and a lower arc portion 76. The upper arc portion 72 extends in an arc shape along the upper arc shape of the second housing 12B. A notch 73 is formed in the widthwise center of the upper arc portion 72. The pair of straight portions 74 extend parallel to each other along the axis Ax. The lower arc portion 76 extends in an arc shape along the lower arc shape of the second housing 12B. A notch 77 is formed in the widthwise center of the lower arc portion 76. The multiple notches 73 formed in each of the multiple upper arc portions 72 and the multiple notches 77 formed in each of the multiple lower arc portions 76 are arranged in a straight line along the axis Ax.

[0052] As shown in Figure 4, among the multiple outlet ribs 58, the projection length of the outlet rib 58a located closest to the center from the second liquid chamber forming surface 54 is greater than the projection lengths of the other outlet ribs 58b and 58c. On the other hand, the heights of the multiple outlet ribs 58 in the second housing 12B (the positions of the protruding ends of the multiple outlet ribs 58 in the X direction) are the same for all of them. That is, although the projection heights of the multiple outlet ribs 58 from the second liquid chamber forming surface 54 are different for all of them, the straight line connecting the protruding ends of the multiple outlet ribs 58 is parallel to the filter material 14 (parallel to the Y direction).

[0053] As shown in Figure 6, when viewed from the thickness direction, the multiple outflow compartments 70 are arranged in parallel from the center of the second housing 12B outwards. The outflow compartment 70a located furthest in the center of the multiple outflow compartments 70 extends in the first direction (axial direction / Z direction). The width W3 of the innermost outflow compartment 70a is larger than the width W4 of the other outflow compartments 70b and 70c.

[0054] As shown in Figure 4, the thickness (dimension in the X direction) of the multiple outflow compartments 70 increases as they move towards the center in the width direction. Therefore, among the multiple outflow compartments 70, the thickness of the outflow compartment 70a located in the center is the largest, and the thickness of the outflow compartment 70d located on the outermost side is the smallest.

[0055] As shown in Figure 3, the outlet opening 62 opens at the second liquid chamber forming surface 54. The outlet opening 62 communicates with the liquid outlet chamber 18 and faces the filter material 14 and the liquid outlet chamber 18. The outlet opening 62 extends in the first direction (axial direction / Z direction). One end (upper end) of the outlet opening 62 in the extending direction is adjacent to the second pressing rib 56 at the upper part of the second housing 12B. The other end (lower end) of the outlet opening 62 is adjacent to the second pressing rib 56 at the lower part of the second housing 12B. Thus, the outlet opening 62 extends from the lower part to the upper part of the second housing 12B. For this reason, the outlet opening 62 communicates directly with multiple outlet compartments 70.

[0056] The guide channel 60 is a groove-shaped channel that is recessed in the X2 direction relative to the second liquid chamber forming surface 54 and extends in the first direction. The outflow opening 62 is one end of the guide channel 60 in the X direction. Therefore, the guide channel 60 extends from the top to the bottom of the second housing 12B. The guide channel 60 has a first end 60a, which is one end in the first direction, and a second end 60b, which is the end opposite to the first end 60a.

[0057] The groove bottom 78 of the guide channel 60 is inclined with respect to the first direction such that the distance from the filter material 14 increases as you move from the first end 60a to the second end 60b. Therefore, the groove depth of the guide channel 60 (the distance from the second liquid chamber forming surface 54 to the groove bottom 78 in the thickness direction) is minimum at the lower end of the guide channel 60 and maximum at the upper end of the guide channel 60. The groove depth at the upper end (deepest part) of the guide channel 60 is, for example, five times or more the groove depth at the lower end (shallowest part) of the guide channel 60.

[0058] The groove bottom 78 has a plurality of inclined sections 80 with different inclination angles with respect to the first direction. In this embodiment, the plurality of inclined sections 80 include a first inclined section 80a and a second inclined section 80b. The first inclined section 80a is formed below the second inclined section 80b. The second inclined section 80b is formed between the first inclined section 80a and the outflow recess 64. The second inclined section 80b has a larger inclination angle than the first inclined section 80a. The groove bottom 78 may have three or more inclined sections 80 with different inclination angles.

[0059] Specifically, the first inclined portion 80a and the second inclined portion 80b are each arc-shaped. For this reason, the first inclined portion 80a can also be called the first curved portion. The second inclined portion 80b can also be called the second curved portion. The radius of curvature of the second inclined portion 80b is smaller than the radius of curvature of the first inclined portion 80a. The radius of curvature of the first inclined portion 80a is, for example, 300 mm to 400 mm, preferably 340 mm to 350 mm. The radius of curvature of the second inclined portion 80b is, for example, 250 mm to 300 mm, preferably 260 mm to 280 mm. In this embodiment, in the first direction, the length L2 of the second inclined portion 80b is shorter than the length L1 of the first inclined portion 80a in the first direction. Note that the length L2 of the second inclined portion 80b may be the same as the length L1 of the first inclined portion 80a, or it may be longer than the length L1 of the first inclined portion 80a.

[0060] The outflow recess 64 is a groove that communicates with the guide channel 60 and is recessed in the X2 direction relative to the guide channel 60. The outflow recess 64 opens at the second end 60b of the guide channel 60. For this reason, the outflow recess 64 is provided on the upper part of the second housing 12B when the medical filter 10 is in use. Here, as shown in Figure 6, the dimension of the outflow recess 64 in the axial direction (Z direction) is denoted as the first dimension S1. The dimension of the outflow recess 64 in the width direction (Y direction) is denoted as the second dimension S2. In this embodiment, the first dimension S1 and the second dimension S2 of the outflow recess 64 are larger than the channel diameter 66d at the upstream end of the outflow channel 66. It is also possible that only one of the first dimension S1 and the second dimension S2 is larger than the channel diameter 66d at the upstream end of the outflow channel 66. The cross-sectional shape of the outflow channel 66 is circular, and the outflow channel 66 opens in a circular shape on the surface communicating with the outflow recess 64.

[0061] As shown in Figure 3, the outflow channel 66 is formed in the second projection 52 of the second housing 12B. The outflow channel 66 communicates with the outflow recess 64 and extends in a direction intersecting the recess direction of the outflow recess 64. In this embodiment, the outflow channel 66 extends in the axial direction (Z direction) of the housing 12. Liquid flows into the outflow channel 66 via the outflow recess 64. The upstream end of the inflow channel 22 is connected to the outflow recess 64. The outflow channel 66 is formed such that the channel diameter increases from the upstream end to the downstream end.

[0062] The outlet tube insertion hole 68 is a hole into which the outlet tube 108 is inserted. The outlet tube 108 is joined to the outlet tube insertion hole 68, for example, by adhesive. The outlet tube insertion hole 68 is formed in the second projection 52 of the second housing 12B. The outlet tube insertion hole 68 has a first tapered hole 68A and a second tapered hole 68B. The first tapered hole 68A opens to the outer surface of the second housing 12B (the lower end surface of the second projection 52). The second tapered hole 68B constitutes the upper part of the outlet tube insertion hole 68. The first tapered hole 68A tapers upwards. In the assembly process, the first tapered hole 68A functions as a guide hole when inserting the outlet tube 108 into the outlet tube insertion hole 68.

[0063] The second tapered hole 68B is formed between the first tapered hole 68A and the outflow channel 66. The lower end of the second tapered hole 68B is connected to the upper end of the first tapered hole 68A. The second tapered hole 68B decreases in diameter towards the top. The second tapered hole 68B is longer than the first tapered hole 68A. The taper angle of the first tapered hole 68A is greater than the taper angle of the second tapered hole 68B.

[0064] A cavity 82 is formed between the outflow tube insertion hole 68 and the second housing body 50. The cavity 82 opens at the lower end surface of the second projection 52 and extends in the axial direction (Z direction).

[0065] The filter material 14 is a sheet-like member placed inside the housing 12. The filter material 14 is formed in an oval shape, similar to the housing 12 (see Figure 2). The filter material 14 is sandwiched between the first housing 12A and the second housing 12B. Specifically, the peripheral edge of the filter material 14 is held around its entire circumference by a first pressing rib 28 provided on the first housing 12A and a second pressing rib 56 provided on the second housing 12B.

[0066] The filter material 14 is a sheet-like member that acts as a flow path for the liquid as it moves from the liquid inlet chamber 16 to the liquid outlet chamber 18, separating and removing a predetermined component (in this embodiment, white blood cells) from the liquid. The filter material 14 is composed of, for example, multiple porous sheets 14a of the same shape stacked in the thickness direction. Porous sheets 14a with different pore sizes may be stacked so that the pore size of the sheet positioned downstream becomes smaller. The periphery of the main sheet and the pre-sheet is made by fusing them using high-frequency fusion or ultrasonic fusion, and this fusion closes the communication holes for blood filtration, forming a fused section from which blood is not filtered. The fusion may be performed before being housed in the housing 12, or it may be performed simultaneously with the fusion of the housing 12. Examples of such porous sheets 14a include polyurethane sponge sheets (sponge-like porous membranes) and nonwoven fabrics. Examples of sponge-like porous membranes include polyether-type polyurethane and polyester-type polyurethane. Examples of nonwoven fabrics include polyethylene terephthalate and polybutylene terephthalate.

[0067] The medical filter 10 configured as described above is used as follows.

[0068] In Figure 1, the medical bag system 100 is suspended by appropriate suspension devices with the platelet bag 102 relatively above and the pooling bag 104 relatively below. The platelet-containing fluid flows out of each platelet bag 102 due to gravity and enters the medical filter 10 via the outflow tube 108. In Figure 3, the platelet-containing fluid flows downward through the inflow channel 22 and enters the liquid outflow chamber 18 via the inflow recess 24 and the inflow opening 26.

[0069] As shown in Figure 5, the platelet-containing fluid that flows into the liquid outlet chamber 18 through the inflow opening 26 is distributed into multiple inflow compartments 46. The platelet-containing fluid flows up to the top of the multiple inflow compartments 46. As shown in Figure 3, the platelet-containing fluid passes through the filter material 14 from the liquid inflow chamber 16 to the liquid outlet chamber 18. During this process, leukocytes in the platelet-containing fluid are captured and removed.

[0070] The platelet-containing fluid flows from the liquid outflow chamber 18 into the guide channel 60. The platelet-containing fluid that flows into the guide channel 60 flows upward along the guide channel 60 and flows into the outflow recess 64. The platelet-containing fluid flows into the outflow channel 66 via the outflow recess 64. As the platelet-containing fluid flows into the outflow channel 66 via the outflow recess 64, air pockets are formed at the top of the outflow recess 64 by the air bubbles contained in the platelet-containing fluid. In other words, as the platelet-containing fluid flows into the outflow channel 66 via the outflow recess 64, the air bubbles are trapped at the top of the outflow recess 64. Therefore, the inflow of air bubbles into the outflow channel 66 is prevented, and the outflow channel 66 is not blocked. The platelet-containing fluid flows downward through the outflow channel 66 and flows into the outflow tube 108, where it is discharged from the medical filter 10.

[0071] This embodiment provides the following effects.

[0072] As shown in Figure 5, the liquid inlet chamber 16 is divided into multiple inlet compartments 46 (46a to 46d) communicating with the inlet opening 26 by at least one inlet-side rib 30. The opening width of the inlet opening 26, when viewed along the thickness direction of the filter material 14, increases towards the outer edge of the first housing 12A. With this configuration, the liquid to be filtered can be efficiently distributed to the multiple inlet compartments 46. This improves the filtration efficiency.

[0073] An inlet opening 26 is provided between the two ends of the extending direction of the outermost inlet rib 30c among the multiple inlet ribs 30. With this configuration, the liquid can be efficiently distributed to the outermost inlet compartment 46d, thereby equalizing the distribution of liquid to the multiple inlet compartments 46.

[0074] Of the multiple inflow compartments 46, the inflow compartment 46a located in the center extends in the axial direction. With this configuration, the central part of the filter media 14 can be efficiently utilized, and the utilization efficiency of the filter media 14 can be improved.

[0075] As shown in Figure 4, the first liquid chamber forming surface 27 of the first housing 12A is curved in a concave shape so that it is furthest from the filter material 14 in the central part in the width direction (Y direction). With this configuration, by efficiently distributing the liquid to the central inflow compartment 46a, variations in liquid distribution to the multiple inflow compartments 46 can be reduced, and the utilization efficiency of the filter material 14 can be improved.

[0076] In the multiple inlet ribs 30, the protrusion length of the inlet rib 30a located closest to the center from the first liquid chamber forming surface 27 is greater than the protrusion lengths of the other inlet ribs 30b and 30c. With this configuration, the thickness of the inlet compartment 46a located closest to the center can be maximized in the multiple inlet compartments 46.

[0077] As shown in Figure 3, the inlet opening 26 is located at the bottom of the housing 12 when the medical filter 10 is in use. The outlet opening 62 is located at the top of the housing 12 when the medical filter 10 is in use. With this configuration, the liquid can be efficiently spread over the filter medium 14, thereby improving the efficiency of use of the filter medium 14.

[0078] In the inlet tube insertion hole 20, the taper angle of the first tapered hole 20A is greater than the taper angle of the second tapered hole 20B. With this configuration, the work efficiency when inserting the inlet tube 106 into the inlet tube insertion hole 20 during the assembly process of the medical filter 10 can be improved.

[0079] As shown in Figure 6, the liquid outlet chamber 18 provided in the second housing 12B is divided into multiple outlet compartments 70 (70a to 70d) that communicate with the outlet opening 62 by at least one outlet-side rib 58. With this configuration, the liquid that has passed through the multiple outlet compartments 70 can be efficiently flowed into the outlet opening 62.

[0080] At least one of the first dimension S1 and the second dimension S2 of the outflow recess 64 is larger than the flow channel diameter 66d at the upstream end of the outflow channel 66. With this configuration, since at least one of the first dimension S1 and the second dimension S2 of the outflow recess 64 is larger than the flow channel diameter 66d at the upstream end of the outflow channel 66, the liquid can be efficiently flowed from the liquid outflow chamber 18 through the outflow opening 62 to the outflow channel 66. This improves the filtration efficiency.

[0081] As shown in Figure 4, the second liquid chamber forming surface 54 is curved in a concave shape so that it is furthest from the filter material 14 in the central part in the width direction. With this configuration, the liquid can be efficiently distributed to the central outflow compartment 70a, and the utilization efficiency of the filter material 14 can be improved.

[0082] In the multiple outlet ribs 58, the protrusion length of the centrally located outlet rib 58a from the second liquid chamber forming surface 54 is greater than the protrusion lengths of the other outlet ribs 58b and 58c. With this configuration, the thickness of the centrally located outlet compartment 70a can be maximized in the multiple outlet compartments 70.

[0083] As shown in Figure 3, the groove bottom 78 of the guide channel 60 formed in the second housing 12B is inclined axially such that the distance from the filter material 14 increases from the first end 60a to the second end 60b. The groove bottom 78 has a plurality of inclined sections 80. The second inclined section 80b has a larger inclination angle than the first inclined section 80a. With this configuration, the groove bottom 78 of the guide channel 60 has a progressively larger inclination angle toward the outflow recess 64. Therefore, the liquid filtered by the filter material 14 can be effectively guided from the liquid outflow chamber 18 through the guide channel 60 to the outflow recess 64. This improves the filtration efficiency.

[0084] Each of the first inclined section 80a and the second inclined section 80b is arc-shaped. The radius of curvature of the second inclined section 80b is smaller than the radius of curvature of the first inclined section 80a. With this configuration, the first inclined section 80a and the second inclined section 80b are not simply inclined in a straight line, but are curved in shape, which makes it difficult for blood to accumulate and allows filtered blood to be smoothly guided into the outflow recess 64. Because the first inclined section 80a and the second inclined section 80b are formed in an arc shape, the liquid can be guided more effectively from the liquid outflow chamber 18 to the outflow recess 64 via the guide channel 60.

[0085] The outflow channel 66 is formed such that its diameter increases from the upstream end to the downstream end. With this configuration, the liquid that flows into the outflow channel 66 via the outflow recess 64 can be effectively guided to the outside of the second housing 12B.

[0086] In the outlet tube insertion hole 68, the taper angle of the first tapered hole 68A is greater than the taper angle of the second tapered hole 68B. With this configuration, the work efficiency when inserting the outlet tube 108 into the outlet tube insertion hole 68 during the assembly process of the medical filter 10 can be improved.

[0087] In the second housing 12B, a cavity 82 is formed between the outlet tube insertion hole 68 and the second housing body 50. This configuration makes it possible to suppress shape errors of the outlet tube insertion hole 68 due to sink marks when the second housing 12B is molded by injection molding. Furthermore, it is easier to identify the second housing 12B during the assembly of the medical filter 10, thus contributing to improved work efficiency.

[0088] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the intent of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above. [Explanation of symbols]

[0089] 10…Medical filter 12…Housing 12A...First Housing 12B...Second Housing 14...filter medium 16...liquid inflow chamber 18…Liquid outflow chamber 22…Inflow channel 24...Inlet recess 26...Inlet opening 27... Surface forming the first liquid chamber 46... Inflow compartment 54...Second liquid chamber forming surface 58...Outlet side rib 60... Guide channel 62... Outlet opening 64…Outlet recess 66…Outlet channel 70...Outflow section 78...Bottom of the trench 80...Slope part 80a...First slope part 80b…Second slope part

Claims

1. A medical filter comprising a hollow housing and a sheet-like filter material disposed within the housing and dividing the housing into a liquid inlet chamber and a liquid outlet chamber, The housing comprises a first housing that forms the liquid inflow chamber between itself and the filter material, and a second housing that forms the liquid outflow chamber between itself and the filter material, with the filter material sandwiched between the first housing and the second housing. The second housing has a liquid chamber forming surface facing the filter material and forming the liquid outflow chamber between itself and the filter material; a groove-shaped guide channel extending in a first direction perpendicular to the thickness direction of the filter material, recessed relative to the liquid chamber forming surface, with an outflow opening opening at one end of the liquid chamber forming surface; an outflow recess communicating with the guide channel and recessed relative to the guide channel; and an outflow channel communicating with the outflow recess and extending in a direction intersecting the recess direction of the outflow recess. A medical filter wherein at least one of the first dimension of the outflow recess in the first direction and the second dimension of the outflow recess in the second direction perpendicular to the thickness direction and the first direction is greater than the flow path diameter at the upstream end of the outflow channel.

2. In the medical filter according to claim 1, The second housing is provided with a plurality of outflow-side ribs that protrude toward the filter material and extend along the peripheral shape of the second housing, When viewed from the thickness direction, the plurality of outlet-side ribs are provided at intervals from the center outward of the second housing. A medical filter wherein the liquid outlet chamber is divided into multiple outlet compartments communicating with the outlet opening by a plurality of outlet-side ribs.

3. In the medical filter according to claim 2, A medical filter wherein the liquid chamber forming surface is curved in a concave shape so as to be furthest from the filter material at its center in the second direction.

4. In the medical filter according to claim 3, A medical filter in which, among a plurality of outlet ribs, the protrusion length of the centrally located outlet rib from the liquid chamber forming surface is greater than the protrusion lengths of the other outlet ribs.

5. In a medical filter according to any one of claims 1 to 4, The second housing has an outlet tube insertion hole into which an outlet tube is inserted, The outflow tube insertion hole has a first tapered hole opening to the outer surface of the second housing and a second tapered hole formed between the first tapered hole and the outflow channel. A medical filter in which the taper angle of the first tapered hole is greater than the taper angle of the second tapered hole.

6. In the medical filter according to claim 5, The second housing comprises a housing body on which the liquid chamber forming surface is formed, and a protruding portion that extends from the housing body in the thickness direction. The outflow channel and the outflow tube insertion hole are formed inside the protruding portion. A medical filter in which a cavity is formed between the outflow tube insertion hole and the housing body.

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