WO2023085343A1

WO2023085343A1 - Drip chamber filter

Info

Publication number: WO2023085343A1
Application number: PCT/JP2022/041840
Authority: WO
Inventors: 慎吾阪本
Original assignee: ニプロ株式会社
Priority date: 2021-11-11
Filing date: 2022-11-10
Publication date: 2023-05-19
Also published as: TW202335689A

Abstract

A drip chamber filter 10 comprises: a top plate part 11; a lower ring 12; a plurality of ribs 13 that connect the top plate part 11 and the lower ring 12, and that form a plurality of slits 15 therebetween; and a middle ring 14 that connects the ribs together and that extend in the circumferential direction. The ribs 13 each include an outer circumferential section 13a, and a triangular-shaped inner circumferential section 13b. The angle formed by the direction in which a side surface of the inner circumferential section 13b extends and a radial direction is greater than that of the outer circumferential section 13a. The thickness of the middle ring 14 in the radial direction is smaller than the thickness of each rib 13 in the radial direction at a location where the middle ring 14 is formed.

Description

filter for drip chamber

The present disclosure relates to filters for drip chambers.

A filter is installed in the drip chamber of the extracorporeal circulation circuit to remove clots and foreign substances in the blood. Mold filters and mesh filters are mainly used as filters for drip chambers.

Both the mold filter and the mesh filter are required to have the function of properly removing foreign substances, as well as the smooth flow of blood and the ability to easily remove air bubbles during priming. If the blood does not flow smoothly and stagnation occurs, blood coagulation is likely to occur in that part. In addition, if the detachability of air bubbles is poor, the operability during priming is deteriorated. If the device is used while air bubbles remain, it may cause poor blood flow or coagulation.

For this reason, various studies have been made on the shape of the filter so as to improve blood flow and quickly remove air bubbles. For example, in the case of a mold filter, it has been studied to make the upper surface of the transverse member forming the slit a slope so that the blood can flow smoothly through the slit (see, for example, Patent Document 1). In the case of a mesh filter, attempts have been made to make it difficult for blood to stagnate by combining it with a support member to form a three-dimensional shape (see, for example, Patent Document 2).

Japanese Patent Publication No. 2002-525192 JP-A-9-140788

However, conventional filters do not consider the influence of the entire cross member on retention. If there is a plane that intersects the direction of blood flow, blood retention is affected not only by the upstream plane but also by the entire plane. For example, a pocket-like area of stagnant blood flow may occur directly under the cross member. Even if the upper surface of the crossing member is inclined, it is difficult to prevent accumulation in the region immediately below the crossing member. In addition, not only the cross member but also the lower end surface of the rib and the back side of the top plate may cause accumulation, but these are not taken into consideration.

Even in a mesh filter with a support member, retention of air bubbles on the non-mesh top surface is a major problem. Moreover, a step of combining the support member and the mesh is required, which causes an increase in cost. It is also being considered to integrally mold the mesh filter and the support member by insert molding, but in this case advanced molding technology is required. Also, the problem of retention occurs in insert molding as well.

An object of the present disclosure is to realize a filter for a drip chamber in which blood flows smoothly and is less likely to stagnate.

A first aspect of the drip chamber filter of the present disclosure includes a top plate portion, a lower ring, a plurality of ribs connecting the top plate portion and the lower ring and forming a plurality of slits therebetween, and An intermediate ring connecting the ribs to each other is provided, and the ribs have a triangular inner circumference whose circumferential width is smaller toward the radially inner side, and the angle formed by the outer circumference and the radial direction with the extending direction of the side surface is larger than that of the outer circumference. and the radial thickness of the intermediate ring is less than the radial thickness of the rib at the position where the intermediate ring is formed.

According to a first aspect of the drip chamber, the radial thickness of the intermediate ring is thinner than the radial thickness of the ribs at the position where the intermediate ring is formed, so that the accumulation-prone area hidden under the intermediate ring becomes smaller. Therefore, it is possible to prevent blood from stagnation due to the intermediate ring. In addition, since the inner peripheral portion of the rib has a triangular shape in which the angle formed by the extending direction of the side surface and the radial direction is larger than that of the outer peripheral portion, the width of the slit is widened in the inner peripheral portion of the rib. For this reason, the blood can flow smoothly in the slit, and stagnation can be prevented.

A second aspect of the drip chamber filter comprises a top plate portion, a lower ring, and a plurality of ribs connecting the top plate portion and the lower ring and forming a plurality of slits therebetween, the top plate The portion has an inclined lower surface that becomes lower toward the center, and a top surface opening that penetrates vertically.

In the second aspect of the drip chamber filter, the downward blood flow is more likely to occur along the inclined lower surface of the top plate, and thus the lower surface of the top plate is more likely to flow vertically than the lower surface of the top plate is perpendicular to the blood flow. Therefore, retention can be made difficult to occur. In addition, the inflow of blood from the opening of the top plate also causes a downward flow, so that stagnation can be reduced on the entire lower surface of the top plate portion.

In the second aspect of the drip chamber filter, the top plate portion may have an inclined upper surface that slopes downward toward the center. With such a configuration, blood can be easily guided to the opening of the top plate.

In the second aspect of the drip chamber filter, the top plate opening may be formed along the radial direction and may have a shape in which the length in the radial direction is longer than the width in the circumferential direction. With such a configuration, the blood flowing toward the center on the upper surface of the top plate portion is more likely to flow into the opening of the top plate portion, so that stagnation can be further prevented.

A third aspect of the drip chamber filter comprises a top plate portion, a lower ring, and a plurality of ribs connecting the top plate portion and the lower ring and forming a plurality of slits therebetween, wherein the ribs The lower end portion has an inclined region in which the thickness in the radial direction gradually decreases downward so as to form a space on the side.

According to the third aspect of the drip chamber filter, the rib has an inclined region in which the thickness in the radial direction gradually decreases downward, so that the lower end surface of the rib is perpendicular to the blood flow. It does not become a rough surface, and it is possible to make it difficult for retention to occur. In addition, since a space is formed under the rib, the connecting portion between the lower end portion of the filter and the chamber main body does not form a stepped portion, so that it is possible to further prevent accumulation.

A third aspect of the drip chamber filter further comprises an intermediate ring formed between the top plate portion and the lower ring, and the outer peripheral surface of the rib protrudes radially outward at a position intersecting the intermediate ring. It can have a stepped portion. With such a configuration, deformation of the ribs is suppressed, and the width of the slits in the circumferential direction can be easily uniformed, so that the function of preventing blood clots and the like can be improved.

A fourth aspect of the drip chamber filter of the present disclosure includes a mesh filter and a filter holding portion that holds the mesh filter in a cylindrical shape, and the filter holding portion includes a top plate portion, a lower ring, and a top plate portion. and a pillar portion connecting the lower ring, the top plate portion has the highest position of the lower surface at the outer edge, and has a top plate opening that penetrates vertically, and the top plate opening is higher at the lower end than at the upper end The minimum gap width is small, and the inner surface of the mesh filter is tightly fixed to the outer surface of the filter holder.

In the fourth aspect of the drip chamber filter, the bottom surface of the top plate portion is the highest at the outer edge, so that the upper end of the filter does not have an upwardly convex depression that causes blood to stagnate. , can suppress retention. In addition, the top plate portion has a top plate opening penetrating vertically, and the top plate opening has a minimum gap width smaller at the lower end than at the upper end. Therefore, the ability to prevent the passage of clots and foreign substances is high, and air bubbles are easily removed during priming. Furthermore, since the inner surface of the mesh filter is tightly fixed to the outer surface of the filter holding part, it is easy to attach the mesh filter to the filter holding part, and the mesh filter is less likely to deform, allowing blood to pass through smoothly. can be made

In a fourth aspect of the drip chamber filter, a plurality of top plate openings are formed on the periphery surrounding the center of the top plate portion, the hole wall on the outer edge side is a vertical surface, and the hole wall on the center side is a vertical surface. The inclined surface can be inclined so as to approach the hole wall on the outer edge side toward the lower side. With such a configuration, the thickness of the outer edge of the top plate can be made constant, and distortion during molding can be suppressed, so that the mesh filter can be easily fixed to the outer surface of the top plate. .

In a fourth aspect of the drip chamber filter, the top plate portion may have a lower convex portion that protrudes from the position of the top plate opening toward the center of the top plate portion on the bottom surface and has a projection height that gradually increases. . With such a configuration, air bubbles that have reached the top plate portion can be easily moved to the outer edge portion where the top plate opening is located, and the air bubbles can be easily removed.

In the fourth aspect of the drip chamber filter, the outer diameter of the lower ring may match the outer diameter of the top plate. With such a configuration, the mesh filter can be fixed in a columnar shape, and the amount of blood passing through the mesh filter becomes substantially constant, so blood is less likely to stagnate in the filter and the occurrence of blood coagulation can be suppressed. can be done.

In a fourth aspect of the drip chamber filter, the flange has a flange projecting radially outward from the lower ring, the flange has a notch on the outer peripheral surface, and the notch is in circumferential position with respect to the pillar. may be provided to match. With such a configuration, it becomes easy to wind the filter mesh around the filter holding portion by rotating the filter holding portion while holding it between the jigs, and to fix the filter mesh in close contact with the filter holding portion.

According to the filter of the present disclosure, retention in the drip chamber filter can be made difficult.

1 is a cross-sectional view showing a drip chamber according to a first embodiment; FIG. It is a side view which shows the filter which concerns on 1st Embodiment. It is a top view showing a filter concerning a 1st embodiment. 1 is a cross-sectional view showing a filter according to a first embodiment; FIG. It is sectional drawing which expands and shows a rib. FIG. 4 is a cross-sectional view taken along line VI-VI of FIG. 3; It is sectional drawing which expands and shows the fitting part of a filter and a chamber main body. It is sectional drawing which expands and shows a top-plate opening part. FIG. 5 is a cross-sectional view showing a drip chamber according to a second embodiment; It is a perspective view showing a filter according to a second embodiment. It is a perspective view which shows the filter holding|maintenance part which concerns on 2nd Embodiment. 12 is a cross-sectional view taken along line XII-XII of FIG. 11; FIG. FIG. 12 is a cross-sectional view taken along line XIII-XIII of FIG. 11; FIG. 12 is a cross-sectional view taken along line XIV-XIV in FIG. 11;

As shown in FIG. 1, the drip chamber according to the first embodiment has a chamber main body 200 and a filter 10 housed therein. The chamber body 200 has a tubular portion 201 and an upper cap 203 attached to the upper portion of the tubular portion 201 . The top cap 203 has multiple ports 231 to which the tubes 301 are connected. The number and arrangement of ports 231 provided in the top cap 203 are not particularly limited. The port 231 can also be provided on the side surface of the upper cap 203 or the side surface of the tubular portion 201 . A lower end portion of the cylindrical portion 201 is tapered downward, and a tube 302 is connected to the lower end. The filter 10 is fitted inside the lower end portion of the tubular portion 201 . Although an example in which the chamber main body is formed of two members, the upper cap and the cylindrical portion, has been shown, it may be configured to be formed of more members.

As shown in FIGS. 2 to 8, the filter 10 is a molded filter and has a top plate portion 11, a lower ring 12 and a plurality of ribs 13. The ribs 13 connect the top plate portion 11 and the lower ring 12, and slits 15, which are openings, are formed between adjacent ribs 13. As shown in FIG.

Between the top plate portion 11 and the lower ring 12 are formed two intermediate rings 14 that connect the ribs 13 in the circumferential direction. For this purpose, the slit 15 is divided into three parts in the height direction by the intermediate ring 14 . Since each part divided in the height direction of the slit 15 has a vertically long shape whose height is sufficiently larger than the width in the circumferential direction, the direction in which the vertically long slit 15 extends is perpendicular to the direction in which the blood and the priming solution flow. do not. Since the air bubbles trapped in the slit 15 are pushed by the flow of the liquid and move vertically in the slit 15, the air bubbles easily pass through the slit 15, and the detachability of the air bubbles is improved.

By forming the intermediate ring 14, deformation of the rib 13 is suppressed, and the width of the slit 15 can be easily made uniform. The number of intermediate rings 14 may be appropriately selected according to the height of the filter 10 and the like, and may be one or three or more. However, from the viewpoint of making it difficult for air bubbles to stay, the length in the height direction of one slit 15 divided in the height direction by the intermediate ring 14 is preferably 10% or more of the height of the filter 10, or more. Preferably it is 20% or more. Note that the intermediate ring 14 may not be provided if deformation of the rib 13 can be sufficiently prevented.

As shown in FIG. 5 , each rib 13 has a columnar shape having an outer circumferential surface extending in the circumferential direction and side surfaces extending radially inward, and having a circumferential width that decreases radially inward. The cross-sectional shape of the rib 13 is a substantially pentagonal shape in which a substantially isosceles trapezoidal outer peripheral portion 13a and a substantially triangular inner peripheral portion 13b are combined. The angle θ ₂ formed by the extending direction of the side surfaces of the inner peripheral portion 13b with the radial direction is larger than the angle θ ₁ formed between the extending direction of the side surfaces of the outer peripheral portion 13a and the radial direction. As a result, the circumferential width of the slit 15 formed between the ribs 13 is longer on the radially inner side than on the radially outer side. In this embodiment, the circumferential width of the slit 15 is substantially constant at the outer peripheral portion or slightly decreases toward the radially inner side, and increases toward the radially inner side at the inner peripheral portion 13b. ing. The width of the slit 15 in the circumferential direction is appropriately determined according to the required characteristics. It can be about 2.0 mm. The number of ribs 13 can be appropriately selected in consideration of the slit width and the diameter of filter 10 .

The cross-sectional shape of the rib 13 is formed by combining the substantially isosceles trapezoidal outer peripheral portion 13a and the substantially triangular inner peripheral portion 13b. This shape has higher strength than triangular ribs and can be less likely to deform. Moreover, unlike ribs having a substantially triangular cross-section, there is a portion with a constant slit width, so that foreign matter blocking function can be enhanced. On the other hand, since the slit width can be increased on the inner side in the radial direction as compared with ribs having a substantially isosceles trapezoidal cross section, blood can easily flow and stagnation can be prevented. Furthermore, since the angle formed by the outer peripheral surface of the rib and the side surface is larger than that of the rib having a substantially triangular cross-section, damage to blood cells by the edge is less likely to occur. In addition, the inner end of the inner peripheral portion 13b can be formed in a slightly curved shape.

The intermediate ring 14 becomes a large barrier for blood flowing downward from above. For this reason, a pocket in which the flow is stagnated is likely to occur on the lower side of the intermediate ring 14 . When the width of the slit 15 gradually increases toward the center, if the intermediate ring 14 exists over the entire radial direction of the rib 13, the portion where the intermediate ring 14 fills the slit 15 becomes larger, further increasing the retention. more likely to occur. In the present embodiment, the radial thickness of the intermediate ring 14 is thinner than the radial thickness of the rib 13 at the position where the intermediate ring 14 is formed, and the intermediate ring 14 is not present on the inner peripheral portion 13b, and the outer peripheral portion 13a. There is an intermediate ring at the outer edge only. Since the intermediate ring 14 connects the portion of the outer peripheral portion 13 b having a narrow circumferential width of the slit 15 , the portion where the intermediate ring 14 fills the slit 15 is smaller than the intermediate ring connecting the entire radial width of the rib 13 . can be reduced, it is possible to make retention less likely to occur.

As shown in FIG. 6, the outer peripheral surface of the rib 13 has a step at the position where the intermediate ring 14 is formed. However, the inner peripheral surface of the rib 13 does not have a step even at the position where the intermediate ring 14 is formed. Inside the filter 10, the ribs 13 are not stepped and connected flatly, so that the blood flows smoothly and is less likely to stagnate. In addition, the detachability of air bubbles is also improved. Although the strength of the filter 10 can be easily increased by providing a step on the outer peripheral surface of the rib 13, the step need not be formed. Further, it is also possible to adopt a configuration in which a slight level difference is generated inside the rib 13 .

The rib 13 of this embodiment has an inclined region 18 at its lower end where the thickness in the radial direction gradually decreases toward the lower end of the lower ring 12 and the thickness in the radial direction becomes substantially zero near the lower end of the lower ring 12 . . As shown in FIG. 7, the formation of the sloped regions 18 creates spaces 19 below the ribs 13 . Generally, the filter 10 is fixed to the chamber main body 200 by inserting the lower ring 12 into the groove 201a formed in the tubular portion 201 . For this reason, the inclined surface forming the inclined region 18 is smoothly connected to the inner wall surface of the chamber main body almost without steps. If there is no inclined region 18 and the thickness of the rib 13 in the radial direction is constant up to the lower end, the lower end surface of the rib 13 becomes a surface substantially perpendicular to the direction of flow, and a step occurs at the lower end of the rib 13 . In this case, if the lower end of the rib 13 is aligned with the lower end of the lower ring 12 and the lower surface of the groove portion 201a is widened to the inner peripheral end of the rib 13, there is no step at the lower end of the rib 13, but the lower end of the slit 15 is closed. It will come off and cause a step. Any step causes blood to stagnate. However, as shown in FIG. 7, the ribs 13 of the present embodiment can prevent a step from being generated at the lower end of the ribs 13, thereby suppressing the occurrence of stagnation. In addition, although the upper end of the inclined region 18 is aligned with the upper end of the lower ring 12 in this embodiment, it does not have to be aligned. The position where the radial thickness of the lower ring 12 becomes 0 does not have to be completely aligned with the lower end of the lower ring 12 . Also, the radial thickness of the ribs 13 may not be completely zero.

The inner peripheral surface of the lower ring 12 preferably matches the outer peripheral surface of the rib 13 and is connected without steps. By doing so, the lower end of the slit 15 is not blocked by the upper surface of the lower ring 12, so that it is possible to prevent accumulation. In this embodiment, a notch 16 is formed in the outer peripheral surface of the lower ring 12 . The notch 16 corresponds to a gate portion for injecting resin at the time of molding.

As shown in FIG. 8, in the present embodiment, the top plate portion 11 has a lower surface 22 that slopes downward toward the center. Air bubbles moving upward inside the filter 10 and reaching the top plate portion 11 are guided radially outward by the lower surface 22 of the top plate portion 11 which is an inclined surface that gradually rises from the center toward the outer edge. In the filter 10 of this embodiment, the slit 15 extends to the bottom surface 22 of the top plate portion 11 . Therefore, air bubbles reaching the outer edge of the top plate portion 11 are easily discharged from the slit 15 to the outside of the filter. Also, during use, the blood that has flowed into the filter 10 from the upper end of the slit 15 flows downward along the slanted lower surface 22, so that the blood flows smoothly under the top plate portion 11. can be made less likely to occur.

Although the height difference h1 between the center and the outer edge of the lower surface 22 of the top plate portion 11 is not particularly limited, it is preferably about 1.6 mm from the viewpoint of improving air bubble removal. However, the lower surface 22 of the top plate portion 11 is not limited to an inclined surface, and may be a horizontal surface with no height difference.

In this embodiment, the upper surface 21 of the top plate portion 11 also has a shape with a depressed central portion, and at least a portion of the upper surface 21 is an inclined upper surface. In this embodiment, since the inclination of the inclined portion of the upper surface 21 substantially matches the inclination of the lower surface 22, the thickness of the top plate portion 11 can be made substantially constant from the central portion to the outer edge portion. By making the thickness of the top plate portion 11 substantially constant, sink marks are less likely to occur during injection molding, and the molding accuracy is improved. function can be realized. Furthermore, the injection pressure during injection molding can be reduced. When the injection pressure becomes high, burrs are likely to occur in the thin rib 13 portion, and the burrs on the rib 13 cause hemolysis. However, the inclination of the upper surface 21 of the top plate portion does not have to match the inclination of the lower surface 22 . Also, the upper surface 21 can be a horizontal surface without a height difference.

In this embodiment, the top plate portion 11 is formed with a top plate opening portion 17 penetrating vertically. At the time of priming, air bubbles are also discharged from the top plate opening 17 to the outside of the filter. During use, blood flows into the filter 10 not only through the slit 15 but also through the opening 17 of the top plate. As a result, a downward flow is generated under the top plate portion 11, so that retention on the bottom side of the top plate portion 11 can be reduced. The top plate opening 17 of the present embodiment is formed along the radial direction and has a substantially rectangular shape with a radial length longer than a circumferential width. By adopting such a shape, it is possible to make the downward flow more likely to occur. The shape of the opening surface of the top plate opening 17 is not limited to a substantially rectangular shape, and may be a substantially triangular shape, a substantially elliptical shape, or the like whose radial length is longer than the maximum value of the circumferential width.

In addition, three top plate openings 17 are formed radially from the center of the top plate portion 11 . By adopting such a configuration, it is possible to evenly disperse the liquid and make it more difficult for the liquid to stagnate. The number of top panel openings 17 may be one, two, or four or more, and the top panel openings 17 may be formed not only radially but also along the circumferential direction.

Further, the top plate opening 17 is formed so as to gradually widen from the lower end to the upper end, and the radially outer hole wall 17b is steeper than the radially inner hole wall 17a. It has a vertical surface. With such a shape, it is possible to prevent the passage of blood clots and the like while allowing air bubbles to escape easily. Moreover, formation of the top plate opening 17 is facilitated. The inclination of the radially inner hole wall 17a and the radially outer hole wall 17b may be the same, and the angle of inclination is not particularly limited. Further, at least one of the radially inner hole wall 17a and the radially outer hole wall 17b may not be inclined.

In this embodiment, the outer edge of the upper surface 21 of the top plate portion 11 is chamfered. In addition, the depression formed in the central portion is also formed gently. Furthermore, the upper end of the hole wall of the top plate opening 17 is chamfered. Therefore, the upper surface of the top plate portion 11 does not have sharp corners, and the occurrence of hemolysis due to the corners can be suppressed.

Although the filter 10 of this embodiment is not particularly limited, it can be formed by injection molding polypropylene, polyethylene, or the like. Any mold may be used for molding, but by performing injection molding using a mold having a plurality of gates on the lower ring 12 side, a mold having a gate at the center of the top plate portion 11 is formed. Injection pressure can be made smaller than when it is used. As a result, it is possible to reduce the occurrence of burrs particularly on the ribs 13 .

Even with a filter that includes only part of the configuration of the rib 13, the intermediate ring 14, and the top plate portion 11 included in the filter of the present embodiment, blood stagnation can be reduced.

FIG. 9 shows a drip chamber according to the second embodiment. As shown in FIG. 9, the drip chamber according to the second embodiment has a chamber body 200 and a filter 100 housed therein. The chamber body 200 has a tubular portion 205, an upper cap 203 attached to the upper portion of the tubular portion 205, and a lower cap 206 attached to the lower portion. The top cap 203 has multiple ports 231 to which tubes are connected. The number and arrangement of ports 231 provided in the top cap 203 are not particularly limited. The port 231 can also be provided on the side of the top cap 203 . The lower cap 206 is tapered downward and has a tube 302 connected to its lower end. The filter 100 is fitted inside the lower cap 206 . Note that the configuration of the chamber main body 200 is not limited to this.

As shown in FIGS. 10 and 11, the filter 100 has a filter holding portion 101 and a mesh filter 102 held by the filter holding portion 101. As shown in FIGS. The mesh filter 102 is formed in a cylindrical shape surrounding the filter holding portion 101 , and the inner surface of the mesh filter 102 is tightly fixed to the outer surface of the filter holding portion 101 . By arranging the mesh filter 102 on the outer surface of the filter holding portion 101, it is much easier to adhere and fix than when the mesh filter 102 is arranged inside the filter holding portion 101. FIG.

As shown in FIGS. 11 to 14, the filter holding portion 101 has a top plate portion 111, a lower ring 113, and a pillar 112 connecting the top plate portion 111 and the lower ring 113. In this embodiment, two pillars 112 are provided at positions facing each other across the center of the filter holding portion 101 . Therefore, the positions of top plate portion 111 and lower ring 113 can be firmly fixed, and the shape of filter 100 can be stabilized. In addition, since a large opening can be secured on the side surface of the filter holding portion 101, it is possible to prevent accumulation. However, the number of pillars 112 may be one, or three or more.

In addition, the pillars 112 do not protrude radially outward from the top plate portion 111 and the lower ring 113, and the outer surfaces of the top plate portion 111, the pillars 112 and the lower ring 113 are formed flush. Therefore, by wrapping the mesh filter 102 around the outside of the filter holding portion 101 and tightly fixing the inner surface of the mesh filter 102 to the outer surfaces of the top plate portion 111, the pillars 112 and the lower ring 113, the filter 100 can be secured. Easy to form.

The upper end of the mesh filter 102 is fixed to the side surface of the top plate portion 111 , the lower end is fixed to the side surface of the lower ring 113 , and the mesh filter 102 is vertically supported by the pillars 112 . Therefore, mesh filter 102 is less likely to be deformed, and blood can be stably passed therethrough. The length of the pillar 112 may be appropriately set according to the required blood flow rate and the like, but in the case of a filter for a normal blood circuit, it is preferably about 20 mm from the viewpoint of securing an opening. Moreover, the width of the pillar is preferably about 2.5 mm from the viewpoint of securing the strength.

The method for tightly fixing the mesh filter 102 to the filter holding portion 101 can be welding, adhesion, or the like. In the case of welding, the mesh filter 102 may be wrapped around the filter holding portion 101 and then welded by pressing a jig from the outside. When fixed by welding, the melted portion of the filter holding portion 101 forms a structure in which the mesh filter 102 and the mesh filter 102 are entangled, so the fixing method can be easily determined.

In this embodiment, the mesh filter 102 is fixed to the outer surface of the top plate portion 111 . For this reason, there is no need to provide a recess or the like for receiving the mesh filter 102 on the bottom surface of the top plate portion 111. The top plate portion 111 is formed in a thick plate shape, and the bottom surface is positioned closest to the outer edge. getting higher. Therefore, there is no space above the upper end of mesh filter 102 through which blood can pass, and blood is less likely to stagnate. The outer diameter of the top plate portion 111 may be appropriately determined according to the size of the chamber, the required blood flow rate, and the like. Moreover, from the viewpoint of facilitating fixing to the outer surface of the mesh filter 102, it is preferable that the thickness of the outer edge in the axial direction is about 3 mm.

A top plate opening 116 is provided in the top plate portion 111 . By providing the top plate opening 116 in the top plate portion 111, air bubbles can be easily removed during priming. In this embodiment, the top plate opening 116 is in the shape of a groove extending in the circumferential direction and provided between the central portion 111a and the outer edge portion 111b. The center portion 111a and the outer edge portion 111b are connected by spoke portions 111c provided every 90°, and the top plate opening 116 is divided into four.

In this embodiment, the top plate opening 116 has a radial width D2 at the lower end smaller than a radial width D1 at the upper end, as shown in FIG. A radial width D2 at the lower end is a width that does not allow blood clots or the like to pass through. A specific value of D2 may be determined in consideration of various conditions, and may be, for example, about 0.3 mm. By making the radial width D1 at the upper end portion larger than D2, it is possible to prevent passage of blood clots and the like while making it easier for air bubbles to escape during priming. In addition, formation of the top plate opening 116 is facilitated. Although D1 is not particularly limited, it can be, for example, about 1 mm. However, D1 can also be equal to D2.

In the present embodiment, the top plate opening 116 has a hole wall 116b on the side of the outer edge 111b that is a vertical surface, and the hole wall 116a on the side of the central portion 111a approaches the hole wall on the side of the outer edge as it goes downward. It has a sloped surface. By making the hole wall 116b on the outer edge side a vertical surface, the radial thickness of the ring-shaped outer edge portion 111b outside the top plate opening 116 is constant, so that distortion is less likely to occur during molding. The side surfaces of the top plate portion 111 can be made smooth. Therefore, the mesh filter 102 can be easily welded to the side surface of the top plate portion 111 . However, as long as the top plate opening 116 has a radial width that does not allow clots or the like to pass through, the hole wall 116b on the side of the outer edge 111b may be an inclined surface. and the hole wall 116a on the central portion 111a side may be inclined.

In the present embodiment, the top plate opening 116 has a groove shape divided into four in the circumferential direction, but the number of divisions can be set arbitrarily. Alternatively, a plurality of radially extending grooves may be arranged radially.

In this embodiment, the lower surface of the top plate portion 111 is formed with a lower convex portion 117 whose height gradually increases from the outer edge portion 111 b toward the center of the top plate portion 111 . The bubbles that have reached the lower surface of the top plate portion 111 move along the lower surface convex portion 117 toward the top plate opening portion 116 side. Therefore, the air bubbles can be more easily removed during priming. The projection height h1 of the lower surface convex portion 117 is not particularly limited, but is preferably about 1.6 mm from the viewpoint of improving air bubble removal. However, the lower convex portion 117 may be provided as needed, and may not be provided.

In this embodiment, a recess 111d is provided in the central portion of the upper surface of the top plate portion 111 . The concave portion 111d is a trace of a gate at the time of molding, but by providing the concave portion 111d on the upper surface corresponding to the lower surface convex portion 117, it is possible to obtain the effect of suppressing the change in the thickness of the central portion 111a and facilitating molding.

In this embodiment, the outer edge of the upper surface of the top plate portion 111 is chamfered. Moreover, the upper end of the hole wall of the top plate opening 116 is chamfered. Further, the recess 111d is a dish-shaped shallow depression. Therefore, the upper surface of the top plate portion 111 does not have sharp corners, and the occurrence of hemolysis due to the corners can be suppressed.

In this embodiment, the outer diameter of the top plate portion 111 and the outer diameter of the lower ring 113 are the same, and the filter 100 has a columnar shape with a constant outer diameter. In the case of a truncated cone-shaped filter with a larger diameter at the bottom than at the top, the amount of blood passing through the mesh filter 102 increases toward the bottom, so there is a risk of blood stagnation at the top of the filter. Since the filter 100 of the present embodiment has a columnar shape, the amount of blood passing through the mesh filter is substantially constant, and blood is less likely to stagnate in the filter, thereby suppressing the occurrence of blood coagulation. If the shape of the chamber main body 200 is the same, retention outside the filter is less likely to occur in the truncated cone-shaped filter. However, from the viewpoint of suppressing the occurrence of coagulation in the filter, which is a more serious problem, a cylindrical filter is preferable.

Further, by matching the outer diameter of the top plate portion 111 and the outer diameter of the lower ring 113, the mesh filter 102 cut into a rectangular shape can be wound around the filter holding portion 101, so that the filter 100 can be formed very easily. It also has the advantage of being easier to

In this embodiment, a flange portion 114 having a larger outer diameter than the lower ring 113 is provided at the lower end of the lower ring 113 . A notch 114 a is provided in the flange portion 114 at a position corresponding to the pillar 112 . By providing the notch 114a, the filter holding portion 101 can be easily rotated while being sandwiched between jigs. One side of the mesh filter 102 cut into a rectangular shape is arranged at the position of one pillar 112, and the adjacent side is brought into contact with the flange portion 114. When the filter holding portion 101 is rotated, the mesh filter 102 can be removed. It can be easily wrapped around the filter holding portion 101 neatly.

In this embodiment, the flange portion 114 also functions as an attachment portion for attaching the filter 100 to the chamber body 200 . As shown in FIG. 9, the fitting of the flange portion 114 into the recess provided on the inner surface of the lower cap 206 facilitates the attachment of the filter 100 to the chamber main body 200 . However, the fixing of the filter 100 to the chamber main body 200 is not limited to such a method.

The outer diameter of the flange portion 114 is not particularly limited, but is about 10% to 20% larger than the outer diameter of the lower ring 113 from the viewpoint of facilitating winding of the mesh filter 102 and facilitating attachment to the chamber body 200. preferably. The flange portion 114 does not necessarily have to be provided at the lower end of the lower ring 113 unless it is at the upper end. Also, the flange portion 114 may not be provided. A flange portion 114 without the notch 114a can also be provided.

For the mesh filter 102, a mesh having an opening of about 40 μm to 100 μm for normal foreign matter removal can be used, but a mesh made of a relatively hydrophilic material such as polyester is preferable. A mesh that has been subjected to a hydrophilic treatment can also be used. The filter holding part 101 may be made of any material as long as it can tightly fix the mesh filter 102 . When fixing a polyester mesh filter by high-frequency welding, polypropylene is preferable because it is easily weldable.

The drip chamber of this embodiment can be connected to either the arterial side or the venous side of the blood circuit.

The drip chamber filter of the present disclosure is less prone to stagnation and can be used for drip chambers of blood circuits and the like.

REFERENCE SIGNS LIST 10 filter 11 top plate 12 lower ring 13 rib 13a outer periphery 13b inner periphery 14 intermediate ring 15 slit 16 notch 17 top plate opening 17a hole wall 17b hole wall 18 inclined region 19 space 21 upper surface 22 lower surface 100 filter 101 filter holding Portion 102 Mesh filter 111 Top plate portion 111a Central portion 111b Outer edge portion 111c Spoke portion 111d Concave portion 112 Pillar 113 Lower ring 114 Flange portion 114a Notch 116 Top plate opening

116a Hole wall

116b Hole wall 117 Lower convex portion 200 Chamber main body 201 Cylindrical shape Part 201a Groove part 203 Upper cap 205 Cylindrical part 206 Lower cap 231 Port 301 Tube 302 Tube

Claims

A top plate portion, a lower ring, a plurality of ribs connecting the top plate portion and the lower ring and forming a plurality of slits therebetween, and an intermediate ring connecting the ribs in the circumferential direction,
The rib has an outer peripheral portion and a triangular inner peripheral portion in which the angle formed by the extending direction of the side surface and the radial direction is larger than that of the outer peripheral portion,
A filter for a drip chamber, wherein the radial thickness of the intermediate ring is less than the radial thickness of the rib at the position where the intermediate ring is formed.
A top plate portion, a lower ring, and a plurality of ribs connecting the top plate portion and the lower ring and forming a plurality of slits therebetween,
A filter for a drip chamber, wherein the top plate portion has an inclined lower surface that is downward toward the center and a top plate opening that penetrates vertically.
The drip chamber filter according to claim 2, wherein the top plate portion has an inclined upper surface that becomes lower toward the center.
The drip chamber filter according to claim 3, wherein the top plate opening is formed along the radial direction, and the length in the radial direction is longer than the width in the circumferential direction.
A top plate portion, a lower ring, and a plurality of ribs connecting the top plate portion and the lower ring and forming a plurality of slits therebetween,
A filter for a drip chamber, wherein the rib has a sloped region at the lower end of which radial thickness tapers downward to form a space underneath.
further comprising an intermediate ring formed between the top plate portion and the lower ring;
6. The drip chamber filter according to claim 5, wherein the outer peripheral surface of the rib has a stepped portion that protrudes radially outward at a position that intersects with the intermediate ring.
comprising a mesh filter and a filter holder for holding the mesh filter in a cylindrical shape,
The filter holding portion has a top plate portion, a lower ring, and a pillar portion connecting the top plate portion and the lower ring,
The top plate portion has the highest position of the lower surface at the outer edge and has a top plate opening that penetrates vertically,
The top plate opening has a minimum gap width smaller at the lower end than at the upper end,
A drip chamber filter, wherein the inner surface of the mesh filter is tightly fixed to the outer surface of the filter holding portion.
A plurality of the top plate openings are formed on the periphery surrounding the center of the top plate portion, the hole wall on the outer edge side is a vertical surface, and the hole wall on the center side approaches the hole wall on the outer edge side downward 8. The drip chamber filter according to claim 7, wherein the slanted surface is slanted so as to
8. The drip chamber according to claim 7, wherein the top plate portion has a lower convex portion that protrudes from the position of the top plate opening toward the center of the top plate portion on the bottom surface and has a protrusion height that gradually increases toward the center of the top plate portion. filter.
The drip chamber filter according to claim 7, wherein the outer diameter of the lower ring matches the outer diameter of the top plate portion.
having a flange portion protruding radially outward from the lower ring;
The flange portion has a notch portion on the outer peripheral surface,
11. The drip chamber filter according to claim 10, wherein the cutout portion is provided so as to coincide with the pillar portion in the circumferential direction.