Mixing chamber

Abstract

To provide a mixing chamber capable of securing airtightness in the mixing chamber injection molded.SOLUTION: A mixing chamber provided for a blood circuit for hemodialysis includes: a cylindrical chamber body having a chamber space inside and whose one end part is closed with a lid body; a first port 11 provided for a side part of the chamber body and guiding first liquid into the chamber space; and a second port 12 provided side by side for the first port in the side part of the chamber body and guiding second liquid into the chamber space. The one end part of the chamber body is provided with a protrusion part 30 protruding outward in a radial direction from an outer peripheral surface of the chamber body.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a mixing chamber provided on a blood circuit.

Background Art

[0002] One of the dialysis treatment methods is hemodiafiltration (HDF). In hemodiafiltration, the patient's blood is introduced into a dialyzer, where unnecessary waste products in the blood are replaced with useful components in the dialysate, and filtration is also performed to remove many waste products from the blood, ranging from small to large molecular weights. In such a blood circuit for hemodiafiltration, in order to replenish the water that escapes from the blood by filtration, the blood before being introduced into the dialyzer or the blood after being led out from the dialyzer is replenished with the dialysate.

[0003] As a configuration for replenishing the blood with the dialysate in the blood circuit, for example, a mixing chamber as shown in Patent Document 1 is known. This mixing chamber has a vertically long cylindrical main body, and ports for connecting a pressure measuring transducer and the like are provided at the upper part, and two ports for introducing blood and dialysate respectively are provided at the side part.

[0004] Such a mixing chamber is made of resin and can be molded by injection molding. In injection molding, the resin material melted by heat is discharged from a nozzle and injected into the space inside the mold through injection paths such as a spool, a runner, and a gate. Then, after cooling and solidifying the resin, the mold is opened, and a molded product integrated with the dendritic resin (hereinafter, "branch") solidified in the injection path is taken out. And a single molded product is obtained by cutting and removing the branch at the root part of the gate (the connection part between the gate and the molded product).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, when there are a plurality of ports on the side as in Patent Document 1, when removing the branch, a large defect occurs in the connection part with the molded product, the wall thickness of the part where the defect occurs becomes small, and depending on the pressure difference between the inside and outside of the chamber, it has been newly found that the desired airtightness may not be ensured. That is, in the case of a chamber having two ports on the main body side as in Patent Document 1, the volume of the chamber body is larger and the amount of resin to be injected is larger than in the case of a configuration with one port. Therefore, it is necessary to increase the flow path cross-sectional area of the gate, a thick branch is formed, and when removing the branch, a large defect occurs in the chamber body. As a result, there may be a problem of airtightness such as pinholes occurring during manufacturing or use.

[0007] In addition, when injection molding a chamber having two ports on the main body side, compared to a chamber having only one port on the main body side, the injection pressure of the resin tends to increase, and there is also a problem that the connecting portion between the port and the housing is deformed. That is, when there are two ports on the main body side, as the chamber volume increases and the number of locations where the resin needs to flow in laterally increases, the injection pressure of the resin tends to increase. When the injection pressure is high, the resin enters even into the gap of the parting surface of the mold, the mold release property deteriorates, and deformation is likely to occur during mold release. As a result, the connection flow path between the port and the chamber may be deformed, possibly causing an unintended flow when blood is flowing.

[0008] Therefore, an object of the present disclosure is to provide a mixing chamber that can achieve at least one of the problems such as ensuring airtightness and suppressing deformation of the connection flow path in an injection-molded mixing chamber.

MEANS FOR SOLVING THE PROBLEM

[0009] The mixing chamber according to the present disclosure is a mixing chamber provided in a blood circuit for hemodialysis, and includes a cylindrical chamber body having a chamber space inside, a first port provided on a side portion of the chamber body for guiding a first liquid into the chamber space, and a second port provided side by side with the first port on the side portion of the chamber body for guiding a second liquid into the chamber space. One end portion of the chamber body is provided with a protruding portion protruding radially outward from the outer peripheral surface of the chamber body, and the protruding portion has a gate connection mark which is a connection mark of a gate of a mold during injection molding.

[0010] By connecting a gate to the protruding portion and performing injection molding, even if a partial defect occurs when the resin solidified at the gate is removed, the airtightness of the chamber body is not impaired.

[0011] Further, the protruding portion may have a portion that does not overlap with the chamber space at the one end portion when viewed along the axial direction of the chamber body.

[0012] Thereby, even if a large partial defect occurs when the resin solidified at the gate is removed, it is possible to avoid the defect from leading to the chamber space.

[0013] Further, the protruding portions may be provided at positions facing each other with the axis of the chamber body interposed therebetween.

[0014] Thereby, a gate can be connected to each of the plurality of protruding portions, and resin can be injected from each gate. In this case, the residual stress of the resin in the circumferential direction of the chamber is reduced, and the deformation of the chamber including the first port and the second port is suppressed.

[0015] Further, the first port and the second port extend from the peripheral portion of the chamber body in a tangential direction intersecting the axis of the chamber body, and two protruding portions may be provided at intervals from the axis of the chamber body in the extending direction of the first port and the second port.

[0016] As a result, since the relative positional relationship between each protruding portion and each port is similar, the amount of resin (injection pressure) injected into the gate connected to each protruding portion can be equalized. Consequently, the residual stress is reduced and the deformation of the chamber including the first port and the second port is suppressed.

[0017] The mixing chamber according to the present disclosure is a mixing chamber provided in a blood circuit for hemodialysis, and includes a cylindrical chamber body having a chamber space inside, a first port provided on a side portion of the chamber body for guiding a first liquid into the chamber space, and a second port provided side by side with the first port on the side portion of the chamber body for guiding a second liquid into the chamber space. The first port and the second port extend from the peripheral portion of the chamber body in a direction intersecting the axis of the chamber body. In a cross section obtained by cutting at least one of the first port and the second port with a plane including the axis of the port and perpendicular to the axis of the chamber body, the contour of the connecting portion between the outer surface of the port and the outer surface of the chamber body forms a curved shape.

[0018] As a result, in the port where the contour of the connecting portion forms a curved shape, during injection molding, the fluidity of the resin flowing from the chamber into the port is improved, and the flow of the resin in the mold becomes smooth. Consequently, the injection pressure of the resin during injection molding can be kept low, and it is possible to reduce the situation where the connecting flow path is deformed during mold release due to excessive injection pressure.

[0019] Further, the thickness dimension of the connecting portion in the cross section may gradually decrease from the port toward the chamber body. Also, the contour of the connecting portion may form an arc shape having a larger diameter than the contour of the inner surface of the downstream end of the port in the cross section.

[0020] As a result, the flow of the resin from the wall portion of the port to the wall portion of the chamber body becomes smooth, and the injection pressure of the resin during injection molding can be suppressed.

Advantages of the Invention

[0021] According to the mixing chamber according to the present disclosure, it is possible to achieve ensuring airtightness or suppressing an increase in the injection pressure of the resin, and to realize a mixing chamber excellent in production stability.

Brief Description of Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0023] [Regarding the overall configuration of the mixing chamber] FIG. 1 is a perspective view of a mixing chamber 1 according to an embodiment of the present disclosure, FIG. 2 is a front view of the mixing chamber 1, and FIG. 3 is a plan view of the mixing chamber 1. This mixing chamber 1 is provided, for example, on a blood circuit for hemodialysis filtration. In the mixing chamber 1, in addition to measuring the pressure of the introduced blood, a replenishing liquid (dialysate) to be mixed with the blood is also introduced to replenish the moisture that escapes from the blood during filtration.

[0024] As shown in Fig. 1, the mixing chamber 1 includes a cylindrical chamber body 10. The chamber body 10 has a chamber space 2 (see Fig. 4 described later) inside, and one end (upper end) is closed by a lid body 3, while the other end (lower end) is open. Five ports 11 to 15 are provided on this chamber body 10. A bottomed cylindrical housing (not shown) as described in Patent Document 1 is fixed to the lower end, and an outlet port for the blood in the mixing chamber is formed at the lower end of the housing. Note that the chamber body 10 may be configured such that one end (upper end) is open and the other end (lower end) is closed by the lid body 3, and a bottomed cylindrical housing may be fixed to the upper end. Alternatively, the mixing chamber 1 may be formed by having one end (upper end) and the other end (lower end) open and bottomed cylindrical housings fixed to each end. Further, a chamber body 10 in which one end (upper end) and the other end (lower end) are closed by the lid body 3 may be formed.

[0025] The first port 11 and the second port 12 are provided on the circumferential portion of the chamber body 10. Among these, the first port 11 is a port for guiding blood (first liquid) into the chamber space 2, and a blood line 21 is connected to its upstream end. The second port 12 is a port for guiding a replenishing liquid (second liquid) to be mixed with the blood into the chamber space 2, and a replenishing liquid line 22 is connected to its upstream end. Further, the downstream end of the second port 12 is connected to the side portion of the chamber body 10 near the center in the direction of the axis A0 of the chamber body 10. The downstream end of the first port 11 is connected to the side portion of the chamber body 10 on the other end side (lower side) than the second port 12. The first port 11 and the second port 12 extend in a direction intersecting the axial direction in which the chamber body 10 extends. More specifically, they extend in the tangential direction of the outer peripheral surface of the chamber body 10.

[0026] In the following description, for convenience, the concept of direction is defined as follows. That is, one end side where the lid 3 is provided in the axial direction A0 of the chamber body 10 is defined as "upper", and the other end side is defined as "lower". The side where the first port 11 and the second port 12 are provided with respect to the chamber body 10 is defined as "front" (front face), and the opposite side is defined as "rear". Also, in the extending direction of the first port 11 and the second port 12, the direction in which the ports 11 and 12 extend from the connection position with the chamber body 10 is defined as "left", and the opposite side is defined as "right".

[0027] The third port 13, the fourth port 14, and the fifth port 15 all project upward from the upper end of the chamber body 10 and open upward on the lid 3. Further, the third port 13 and the fifth port 15 are located on the front side of the lid 3, and the third port 13 is located on the left side and the fifth port 15 is located on the right side. And the fourth port 14 is located on the rear side of the lid 3 and is located approximately in the center between the left and right.

[0028] Among these, the third port 13 is a port through which air flows to measure pressure, and a transducer is connected to the upper end via a pressure measurement line 23. The fourth port 14 is a port for adjusting the liquid level in the chamber space 2, and a liquid level adjustment line 24 provided with an openable and closable clip is connected to the upper end. The fifth port 15 is a port for appropriately injecting a drug or the like, and a drug injection line 25 is connected to the upper end thereof. Note that it is also possible to eliminate these ports, and it is also possible to additionally provide ports.

[0029] Note that the opening at the lower end of the chamber body 10 forms a fitting portion into which a bottomed cylindrical housing is fitted, and an outlet port is provided at the lower part of the housing. A mixed liquid line 26 is connected to this outlet port, and a mixed liquid composed of blood and a replenishing liquid mixed in the chamber space 2 is sent out through the outlet port.

[0030] In this embodiment, the case where blood is introduced from the first port 11 and a replenishing fluid is introduced from the second port 12 as described above is illustrated, but the present invention is not limited thereto. Conversely, a replenishing fluid may be introduced from the first port 11 and blood may be introduced from the second port 12. However, when blood is introduced from the first port 11 and a replenishing fluid is introduced from the second port 12 as described above, it is possible to suppress the blood from being exposed to the air at the upper part of the chamber space 2 and coagulating. Further, the uses and arrangements of the third port 13, the fourth port 14, and the fifth port 15 are not limited to those described above, and other uses and arrangements may be adopted.

[0031] [Regarding the protruding portion] As shown in FIGS. 1 to 3, a protruding portion 30 that protrudes radially outward from the outer peripheral surface of the chamber body 10, that is, to both outer sides in the left-right direction, is provided at the upper end portion of the chamber body 10. FIG. 4 is a longitudinal sectional view of the mixing chamber cut along line IV-IV in FIG. 3. Note that the cutting plane along this VI-VI line is a plane that passes through the left and right protruding portions 30 and is orthogonal to the front-rear direction. Hereinafter, description will be made with reference to FIGS. 1 to 4.

[0032] As described above, the chamber body 10 has a vertically long cylindrical shape, and its outer peripheral surface 40 has a large-diameter outer peripheral surface 41 that occupies a range from the lower end to the vicinity of the upper end, and a small-diameter outer peripheral surface 43 that is located above the large-diameter outer peripheral surface 41 and has a smaller diameter than the large-diameter outer peripheral surface 41. The step between the large-diameter outer peripheral surface 41 and the small-diameter outer peripheral surface 43 is connected by a stepped surface 42 that is inclined with respect to the axis A0. On the other hand, the inner peripheral surface 45 of the chamber body 10 has a large-diameter inner peripheral surface 46 that occupies a range near the lower end, and a small-diameter inner peripheral surface 47 that occupies a wide range from the upper end of the large-diameter inner peripheral surface 46 to the upper end of the chamber space 2. Note that the large-diameter inner peripheral surface 46 forms a fitting portion into which the upper end opening of the housing is fitted.

[0033] The protruding portion 30 protrudes outward to the left and right from the upper end portion of the small-diameter outer peripheral surface 43 of the chamber body 10. That is, the protruding portions 30 are provided at left and right positions facing each other with the axis A0 of the chamber body 10 interposed therebetween.

[0034] As shown in FIG. 4, the upper surface 31 of the overhanging portion 30 is flush with the upper surface 3a of the lid body 3 that closes the upper end of the chamber body 10. Further, the lower surface 32 of the overhanging portion 30 forms an inclined surface that slopes upward as it extends outward to the left and right from the connection point with the small-diameter outer peripheral surface 43. Therefore, the vertical thickness dimension D1 (the distance between the upper surface 31 and the lower surface 32) of the overhanging portion 30 becomes smaller as it extends outward to the left and right from the connection point with the small-diameter outer peripheral surface 43, and it has an overall tapered shape when viewed from the front (see also FIG. 2).

[0035] Also, as shown in FIGS. 2 and 4, the vertical thickness dimension D1 of the overhanging portion 30 is equal to or greater than the thickness dimension D2 of the lid body 3. In particular, in the overhanging portion 30, even for the outer end portion 33 that is farthest from the small-diameter outer peripheral surface 43, the vertical thickness dimension thereof is equal to or greater than the thickness dimension D2 of the lid body 3 (more preferably, larger than the thickness dimension D2 of the lid body 3). Thereby, a predetermined strength is imparted to the overhanging portion 30, so that it is possible to prevent a situation in which the overhanging portion 30 is damaged and the packaging bag is damaged and torn due to the damaged portion.

[0036] As shown in FIG. 3, when viewed in plan, the overhanging portion 30 protrudes in a triangular shape to the left and right with respect to the lid body 3 and has a shape that smoothly connects with the contour of the lid body 3. Specifically described, the lid body 3 has a circular contour in accordance with the upper end portion of the chamber body 10. Then, among the circular outer peripheral surfaces of the lid body 3, the contour of the right overhanging portion 30 is formed by the tangent lines drawn to the right from the right front position and the right rear position, respectively. Similarly, among the circular outer peripheral surfaces of the lid body 3, the contour of the left overhanging portion 30 is formed by the tangent lines drawn to the left from the left front position and the left rear position, respectively. Further, the outer end portions 33 located at the tops of the left and right overhanging portions 30 have an arcuate contour when viewed in plan.

[0037] Since such an overhanging portion 30 protrudes from the small-diameter outer peripheral surface 43, it does not overlap with the chamber space 2 when viewed in plan along the axis A0 (see Fig. 4). At a predetermined position on the upper surface 31 of the overhanging portion 30, a gate of the mold is connected during injection molding. Therefore, this upper surface 31 has a connection mark of the gate, more specifically, a trace (gate connection mark) 34 obtained by removing the resin cured in the gate after demolding. Accordingly, the gate connection mark 34 is also provided at a position that does not overlap with the chamber space 2 when viewed in plan. Note that the chamber space 2 may adopt a configuration in which the diameter is enlarged, for example, at the large-diameter outer peripheral portion 41. In this case, a part or all of the overhanging portion 30 may overlap with the portion where the diameter is enlarged at the large-diameter outer peripheral portion 41 of the chamber space 2 in plan view. The gate connection mark 34 forms a concave depression with respect to the upper surface 31 of the overhanging portion 30, forms a circular shape in plan view as shown in Fig. 3, and forms an isosceles trapezoid shape with a smaller lower base than the upper base in cross-sectional view as shown in Fig. 4. Since the gate connection mark 34 is concave in this way, the resin injected into the mold and rebounded from the lower surface 31 can flow stably, and when the resin at the gate portion after demolding is removed, it is possible to prevent burrs from protruding from the upper surface 31. However, the shape of the gate connection mark 34 is not limited to such a concave shape, and may be, for example, a flat shape or a convex shape.

[0038] As described above, the mixing chamber 1 includes the overhanging portion 30, and the gate connection mark 34 is provided on the overhanging portion 30. Thereby, when the resin solidified at the gate is removed after demolding, even if a defect such as a pinhole occurs in the resin forming the mixing chamber 1, it is possible to suppress the airtightness of the chamber space 2 from being impaired. In particular, since the gate connection mark 34 is provided on the overhanging portion 30 that does not overlap with the chamber space 2 when viewed in the direction of the axis A0, even if a pinhole occurs in the gate connection mark 34, it is possible to avoid the formation of a through hole communicating with the chamber space 2.

[0039] Further, the protruding portions 30 are provided at left and right positions facing each other with the axis A0 of the chamber body 10 interposed therebetween. Thereby, gates can be connected to each of the two protruding portions 30, and resin can be injected from each gate. In this case, since the amount of resin injected from one gate can be reduced, the gate can have a small diameter, and the defects that can occur in the protruding portion can be suppressed to a small size. Note that the number of protruding portions 30 provided in the chamber body 10 is not limited to two. For example, there may be only one protruding portion 30, or there may be three or more. When a plurality are provided, it is preferable to arrange them at equal intervals around the axis A0.

[0040] [Regarding the First Port and the Second Port] As shown in FIGS. 1 and 2, the first port 11 extends from the peripheral portion on the front side of the chamber body 10 in one of the left and right tangential directions intersecting the axis A0 (the left direction in the figure). The second port 12 located above the first port 11 also extends from the peripheral portion on the front side of the chamber body 10 in one of the left and right tangential directions intersecting the axis A0 (the left direction in the figure). Therefore, the above-described two protruding portions 30 are provided at a distance from the axis A0 in the extending direction (left and right direction) of the first port 11 and the second port 12. Note that the connection positions of the first port 11 and the second port 12 to the chamber body 10 are the large-diameter outer peripheral surface 41 of the outer peripheral surface 40 of the chamber body 10.

[0041] FIG. 5 is a view of a cross section obtained by cutting the mixing chamber 1 with a plane perpendicular to the axis A0 as seen from below, (A) is a cross-sectional view in a plane (VA-VA plane) passing through the first port 11, and (B) is a cross-sectional view in a plane (VB-VB plane) passing through the second port 12. Note that the VA-VA plane is a plane including the axis A1 of the first port 11, and the VB-VB plane is a plane including the axis A2 of the second port 12.

[0042] As shown in Fig. 5(A), the inner peripheral surface 50 of the first port 11 has a guiding surface 51, an inner fitting surface 52, and an introduction surface 53 in order from the opening end on the left side (upstream side). The guiding surface 51 has an inner surface shape with a reduced diameter from the opening end inward (downstream side), and guides the connector when connecting to the connector of the blood line 21 (see Fig. 1). The inner fitting surface 52 externally fits onto the connector of the blood line 21 guided by the guiding surface 51 to connect the blood line 21 and the mixing chamber 1. The introduction surface 53 defines a flow path for guiding the blood flowing through the connected blood line 21 into the chamber space 2.

[0043] The inner diameter of the inner fitting surface 52 is the same as the inner diameter of the downstream end of the guiding surface 51 and is substantially constant over the entire length. The inner diameter of the upstream end of the introduction surface 53 is smaller than the inner diameter of the inner fitting surface 52, and the downstream end on the opposite side opens at the inner peripheral surface 45 (specifically, the small-diameter inner peripheral surface 47) of the chamber body 10. The inner peripheral surface 50 composed of these guiding surface 51, inner fitting surface 52, and introduction surface 53 is formed coaxially with respect to the axis A1. Further, this axis A1 is eccentric at a position that does not intersect in a plan view with respect to the axis A0 of the chamber body 10, and in this embodiment, forms a tangent to the inner peripheral surface 45 (small-diameter inner peripheral surface 47) of the chamber space 2.

[0044] By the way, a part of the downstream portion of the introduction surface 53 forms a curved surface that is curved with respect to the extending direction of the axis A1. More specifically, as shown in Fig. 5(A), the wall portion of the first port 11 has a proximal side wall portion 54 close to the axis A0 across the axis A1 and a distal side wall portion 55 far from the axis A0 on the opposite side. A curved surface 53a is formed on the downstream portion of the introduction surface 53, which is the inner peripheral surface of the distal side wall portion 55. The curved surface 53a is curved such that the contour represented by the cross-section in Fig. 5(A) turns from the direction along the axis A1 to the direction facing the axis A0 (in Fig. 5(A), from the right direction to the right obliquely backward) from the upstream end to the downstream end. Note that the inner peripheral surface of the proximal side wall portion 54 is linear from the upstream end to the downstream end.

[0045] Next, the distal side wall portion 55 of the first port 11 and the chamber body 10 are connected by a connecting portion 56. The outer surface 56a of this connecting portion 56 is curved. More specifically, both the contour in the cross-section orthogonal to the axis A0 (see FIG. 5(A)) and the contour in the cross-section including the axis line A0 of the connecting portion 56 are arc-shaped. Also, as shown in FIG. 5(A), the thickness dimension D3 of the connecting portion 56 gradually decreases from the connection location with the distal side wall portion 55 of the connecting portion 56 (refer to the position of the plane P1 in the figure) toward (approaching) the connection location with the chamber body 10 of the connecting portion 56 (refer to the position of the plane P2 in the figure). Further, in the cross-section shown in FIG. 5(A), the contour of the outer surface of the connecting portion 56 forms an arc shape with a larger diameter than the contour of the curved surface 53a of the first port 11.

[0046] Note that the range of the connecting portion 56 is from the plane P1 including the axis line A0 passing through the downstream end of the inner peripheral surface 50 of the distal side wall portion 55 of the first port 11 to the location where the gradual decrease in the thickness dimension D3 ends (plane P2 in FIG. 5(A)). Also, as shown in FIGS. 1 and 2, when viewed from the front, the connecting portion 56 forms a tapered contour shape in which the dimension in the vertical direction gradually becomes smaller toward the right side (the downstream side of the first port 11). More specifically, the connecting portion 56 forms a contour shape combining an upwardly convex arc and a downwardly convex arc from above and below, and the right end (the end portion on the downstream side of the first port 11) forms a sharp top.

[0047] As described above, the extending directions of the first port 11 and the second port 12 are the same as the separating directions of the two protruding portions 30 with respect to the axis A0. Thereby, the relative positional relationships between each protruding portion 30 and the first port 11 and the second port 12 are similar. Then, the injection amount (injection pressure) of the resin into the gates connected to each protruding portion 30 can be equalized, each gate can be made to have a small diameter, and the defects that can occur in the protruding portion 30 can be suppressed to a small extent.

[0048] Further, in a cross-section (VA-VA plane) that includes the axis A1 of the first port 11 and is cut by a plane orthogonal to the axis A0 of the chamber body 10, the contour of the connecting portion 56 between the outer surface of the first port 11 and the outer surface of the chamber body 10 forms a curved shape. As a result, in the first port 11, during injection molding, the fluidity of the resin flowing from the chamber body 10 into the first port 11 is improved, and the flow of the resin in the mold becomes smooth. Consequently, the injection pressure of the resin during injection molding can be significantly reduced.

[0049] Also, in the connecting portion 56, the thickness dimension D3 in the above cross-section gradually decreases from the first port 11 toward the chamber body 10. Further, the contour of the outer surface 56a of the connecting portion 56 forms an arc shape with a larger diameter than the contour of the curved surface 53a which is the inner surface of the downstream end of the first port 11 in the above cross-section. Moreover, the vertical dimension of the connecting portion 56 forms a tapered shape that gradually becomes smaller toward the downstream side. This smooths the flow of the resin flowing from the chamber body 10 into the first port 11 and can suppress the injection pressure of the resin during injection molding.

[0050] Note that the second port 12 located above the first port 11 also has the same configuration as the above-described first port 11. The configuration of this second port 12 will also be described below with reference to FIG. 5(B).

[0051] As shown in FIG. 5(B), the inner peripheral surface 60 of the second port 12 has a guide surface 61, a fitting surface 62, and an introduction surface 63 in order from the open end on the left side (upstream side). The guide surface 61 has an inner surface shape that tapers inward (downstream side) from the open end, and guides the connector when connecting to the connector of the replenishing fluid line 22 (see FIG. 1). The fitting surface 62 fits over the connector of the replenishing fluid line 22 guided by the guide surface 61 to connect the replenishing fluid line 22 and the mixing chamber 1. The introduction surface 63 defines a flow path for guiding the blood flowing through the connected replenishing fluid line 22 into the chamber space 2.

[0052] The inner diameter of the inner fitting surface 62 is the same as the inner diameter of the downstream end of the guide surface 61 and is substantially constant over the entire length. The inner diameter of the upstream end of the introduction surface 63 is smaller than the inner diameter of the inner fitting surface 62, and the downstream end on the opposite side opens at the inner peripheral surface 45 (specifically, the small-diameter inner peripheral surface 47) of the chamber body 10. The inner peripheral surface 60 composed of these guide surface 61, inner fitting surface 62, and introduction surface 63 is formed coaxially with respect to the axis A2. Further, this axis A2 is eccentric at a position that does not intersect in a plan view with respect to the axis A0 of the chamber body 10, and in this embodiment, it forms a tangent to the inner peripheral surface 45 (small-diameter inner peripheral surface 47) of the chamber space 2.

[0053] Incidentally, a part of the downstream portion of the introduction surface 63 forms a curved surface that is curved with respect to the extending direction of the axis A2. More specifically, as shown in FIG. 5(B), the wall portion of the second port 12 has a proximal side wall portion 64 close to the axis A0 across the axis A2 and a distal side wall portion 65 far from the axis A0 on the opposite side. A curved surface 63a is formed on the downstream portion of the introduction surface 63, which is the inner peripheral surface of the distal side wall portion 65. The curved surface 63a is curved such that the contour represented by the cross section of FIG. 5(B) turns from the direction along the axis A2 toward the direction facing the axis A0 (in FIG. 5(B), from the right direction to the right obliquely backward) as it goes from the upstream end to the downstream end. Note that the inner peripheral surface of the proximal side wall portion 64 is linear from the upstream end to the downstream end.

[0054] Next, the distal side wall portion 65 of the second port 12 and the chamber body 10 are connected by a connecting portion 66. The outer surface 66a of this connecting portion 66 has a curved surface shape. More specifically, both the contour in a cross-section orthogonal to the axis A0 (see Fig. 5(B)) and the contour in a cross-section including the axis A0 of the connecting portion 66 form an arc shape. Also, as shown in Fig. 5(B), the thickness dimension D4 of the connecting portion 66 gradually decreases from the connection location with the distal side wall portion 65 of the connecting portion 66 (refer to the position of the plane P3 in the figure) toward (approaching) the connection location of the connecting portion 66 with the chamber body 10 (refer to the position of the plane P4 in the figure). Further, in the cross-section shown in Fig. 5(B), the contour of the outer surface of the connecting portion 66 forms an arc shape with a larger diameter than the contour of the curved surface 63a of the second port 12.

[0055] Note that the range of the connecting portion 66 is from the plane P3 including the axis A0 passing through the downstream end of the inner peripheral surface 60 of the distal side wall portion 65 of the second port 12 to the location where the gradual decrease in the thickness dimension D4 ends (plane P4 in Fig. 5(B)). Also, as shown in Figs. 1 and 2, when viewed from the front, the connecting portion 66 has a tapered contour shape in which the dimension in the vertical direction becomes smaller as it goes toward the right side (the downstream side of the second port 12). More specifically, the connecting portion 66 has a contour shape formed by combining an upwardly convex arc and a downwardly convex arc from above and below, and the right end (the end portion on the downstream side of the second port 12) forms a sharp top. Further, as shown in Fig. 3, the protruding dimension of the connecting portion 66 from the peripheral surface of the chamber body 10 gradually becomes smaller as it goes toward the downstream side. This is the same for the connecting portion 56 of the first port 11 described above.

[0056] Also, as shown in Fig. 4, when comparing the downstream openings of the first port 11 and the second port 12, both the dimension in the vertical direction and the dimension in the horizontal direction are slightly larger for the lower first port 11. On the other hand, when comparing the curved surfaces 53a and 63a, the dimension in the horizontal direction is slightly larger for the upper second port 12 than for the first port. However, these differences between the first port 11 and the second port 12 are not essential and can be set as appropriate in consideration of the flow rate of the liquid flowing through each port, the efficiency of mixing in the chamber space 2, etc.

[0057] Even with the configuration of the second port 12 and its vicinity as described above, the same operational effects as those described for the configuration of the first port 11 and its vicinity are achieved, but the description thereof is omitted here. In the present embodiment, as described above, both the first port 11 and the second port 12 have the same configuration, and in particular, a configuration including connecting portions 56, 66 having a curved surface shape of the contour is illustrated, but the present invention is not limited thereto. It is sufficient that at least one of the first port 11 and the second port 12 is connected to the chamber body by the connecting portion having the above configuration.

Industrial Applicability

[0058] The present invention can be suitably applied to a mixing chamber provided in a blood circuit for hemodialysis.

Explanation of Signs

[0059] 1 Mixing chamber 2 Chamber space 3 Lid 10 Chamber body 11 First port 12 Second port 30 Protruding portion 56 Connecting portion 66 Connecting portion A0 Axis of the chamber body

Claims

1. A mixing chamber provided in a blood circuit for hemodialysis, comprising: A cylindrical chamber body having a chamber space therein; a first port provided on a side of the chamber body and configured to introduce a first liquid into the chamber space; a second port provided adjacent to the first port on a side portion of the chamber body and configured to introduce a second liquid into the chamber space; the first port and the second port extend from a periphery of the chamber body in a direction intersecting an axis of the chamber body, at least one of the first port and the second port has a contour of a connecting portion between an outer surface of the port and an outer surface of the chamber body that has a curved shape in a first cross section taken along a plane that includes an axis of the port and is perpendicular to an axis of the chamber body, In the first cross section, a contour of an outer surface of the connecting portion and a contour of an inner surface of the downstream end of the port have different shapes, and a thickness dimension of the connecting portion gradually decreases from the port toward the downstream side of the chamber body. Mixing chamber.

2. The dimension of the connecting portion in a direction along the axis is tapered so as to gradually decrease toward the downstream side, and the downstream end forms a peak that is pointed toward the downstream direction.

2. The mixing chamber of claim 1.

3. the connecting portion has an outer surface profile in the first cross section and an outer surface profile in a second cross section cut by a plane including an axis of the chamber body, the outer surface profile both being arc-shaped; 2. The mixing chamber of claim 1.

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