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

[0005]

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

Background Art

[0002] As one of dialysis treatment methods, there 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 removed from the blood by filtration, the dialysate is replenished into the blood before being introduced into the dialyzer or the blood after being led out from the dialyzer.

[0003] As a configuration for replenishing the dialysate to the blood 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 a port for connecting a pressure measuring transducer and the like is 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 formed by injection molding. In injection molding, a resin material melted by heat is discharged from a nozzle and injected into the mold cavity 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 a branched 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

[0006] However, it has recently been discovered that when multiple ports exist on the side, as in Patent Document 1, removing the branch can cause a large defect in the connection part with the molded product, reducing the wall thickness of the defective part, and potentially making it impossible to ensure the desired airtightness depending on the pressure difference between the inside and outside of the chamber. In other words, in the case of a chamber with two ports on the side of the main body, as in Patent Document 1, the volume of the chamber body is larger and the amount of resin injected is larger compared to a configuration with one port. Therefore, it is necessary to increase the flow path cross-sectional area of ​​the gate, which leads to the formation of a large-diameter branch, and when the branch is removed, a large defect occurs in the chamber body. As a result, airtightness problems such as pinholes occurring during manufacturing or use may occur.

[0007] Furthermore, when injection molding a chamber with two ports on the side of the main body, the resin injection pressure tends to increase compared to a chamber with only one port on the side of the main body, which can lead to deformation of the connection between the port and the housing. In other words, having two ports on the side of the main body increases the chamber volume and the number of places where resin needs to flow laterally, which tends to increase the resin injection pressure. High injection pressure can cause resin to seep into the gaps in the parting surface of the mold, worsening the release properties and making deformation more likely during demolding. As a result, the connection flow path between the port and the chamber may deform, potentially causing unintended flow when blood is injected.

[0008] Therefore, the object of this disclosure is to provide a mixing chamber that can achieve at least one of the following problems in an injection-molded mixing chamber: ensuring airtightness and suppressing deformation of the connecting flow path. [Means for solving the problem]

[0009] The mixing chamber according to this disclosure is a mixing chamber provided in a blood circuit for hemodialysis, comprising: a cylindrical chamber body having a chamber space inside; a first port provided on the side of the chamber body for introducing a first liquid into the chamber space; and a second port provided on the side of the chamber body adjacent to the first port for introducing a second liquid into the chamber space, wherein one end of the chamber body is provided with a protruding portion that projects radially outward from the outer circumferential surface of the chamber body, and the protruding portion has a gate connection mark, which is a gate connection mark of a mold used during injection molding.

[0010] This design, which involves connecting a gate to the protruding portion and performing injection molding, ensures that even if some damage occurs when removing the solidified resin at the gate, the airtightness of the chamber body is not compromised.

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

[0012] This prevents the defect from leading to the chamber space, even if a large portion of the solidified resin at the gate is removed.

[0013] Furthermore, the protruding portion may be provided at positions opposite each other across the axis of the chamber body.

[0014] This allows gates to be connected to each of the multiple protruding sections, and resin to be injected from each gate. In this case, residual stress in the chamber circumferentially is reduced, and deformation of the chamber, including the first and second ports, is suppressed.

[0015] Furthermore, the first port and the second port extend from the periphery of the chamber body in a tangential direction intersecting the axis of the chamber body, and two of the protruding portions may be provided spaced apart from the axis of the chamber body in the direction of extension of the first port and the second port.

[0016] As a result, the relative positional relationship between each protrusion and each port becomes similar, allowing for equalization of the amount of resin injected (injection pressure) into the gates connected to each protrusion. Consequently, residual stress is reduced, and deformation of the chamber, including the first and second ports, is suppressed.

[0017] The mixing chamber according to this disclosure is a mixing chamber provided in a blood circuit for hemodialysis, comprising: a cylindrical chamber body having a chamber space inside; a first port provided on the side of the chamber body for introducing a first liquid into the chamber space; and a second port provided on the side of the chamber body adjacent to the first port for introducing a second liquid into the chamber space, wherein the first port and the second port extend from the circumferential portion of the chamber body in a direction intersecting the axis of the chamber body, and in a cross-section cut by a plane that includes the axis of the port and is perpendicular to the axis of the chamber body, the contour of the connection portion between the outer surface of the port and the outer surface of the chamber body is curved.

[0018] As a result, in ports where the contour of the connecting part has a curved shape, the fluidity of the resin flowing from the chamber to the port during injection molding is improved, and the resin flow within the mold becomes smoother. Consequently, the injection pressure of the resin during injection molding can be kept low, which reduces the likelihood of deformation of the connecting channel during demolding due to excessive injection pressure.

[0019] Furthermore, the thickness dimension of the connecting portion in the cross-section may gradually decrease as it moves from the port toward the chamber body. Also, the contour of the connecting portion may be an arc shape with a larger diameter than the contour of the inner surface of the downstream end of the port in the cross-section.

[0020] This allows for a smoother flow of resin from the port wall to the chamber body wall, thereby suppressing the resin injection pressure during injection molding. [Effects 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 the Drawings

[0022] [Figure 1] FIG. 1 is a perspective view of a mixing chamber according to the present embodiment. [Figure 2] FIG. 2 is a front view of the mixing chamber. [Figure 3] FIG. 3 is a plan view of the mixing chamber. [Figure 4] FIG. 4 is a longitudinal sectional view of the mixing chamber cut along line IV-IV of FIG. 3. [Figure 5] FIG. 5(A) is a cross-sectional view of the mixing chamber cut along line VA-VA of FIG. 2, and FIG. 5(B) is a cross-sectional view of the mixing chamber cut along line VB-VB of FIG. 2.

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, the pressure of the introduced blood is measured, and in addition, a replenishing solution (dialysis solution) to be mixed with the blood is introduced to replenish the moisture that escapes from the blood during filtration.

[0024] As shown in Figure 1, the mixing chamber 1 comprises a cylindrical chamber body 10. The chamber body 10 has a chamber space 2 (see Figure 4 below) inside, and one end (upper end) is closed by a lid 3, while the other end (lower end) is open. Five ports 11 to 15 are provided in 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 draining blood from the mixing chamber is formed at the lower end of the housing. The chamber body 10 may be configured with one end (upper end) open and the other end (lower end) closed by a lid 3, with a bottomed cylindrical housing 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, with bottomed cylindrical housings fixed to each end. Furthermore, the chamber body 10 may be formed with one end (upper end) and the other end (lower end) closed by a lid 3.

[0025] The first port 11 and the second port 12 are provided on the periphery of the chamber body 10. The first port 11 is a port that guides blood (first fluid) into the chamber space 2, and a blood line 21 is connected to its upstream end. The second port 12 is a port that guides the replacement fluid (second fluid) to be mixed with the blood into the chamber space 2, and a replacement fluid line 22 is connected to its upstream end. The downstream end of the second port 12 is connected to the side of the chamber body 10 near the center in the direction of the chamber body 10's axis A0. The downstream end of the first port 11 is connected to the side 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, and more specifically, they extend in the tangential direction to the outer surface of the chamber body 10.

[0026] For convenience, the concept of direction used in the following explanation is defined as follows: In the direction of the axial center A0 of the chamber body 10, the end on which the cover 3 is provided is defined as "up," and the other end is defined as "down." The side of the chamber body 10 on which the first port 11 and the second port 12 are provided is defined as "front," and the opposite side is defined as "rear." In addition, in the direction in which the first port 11 and the second port 12 extend, the direction in which the ports 11 and 12 extend from the connection point of the ports 11 and 12 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 are all projecting from the lid 3 at the upper end of the chamber body 10, opening upward. The third port 13 and the fifth port 15 are located on the front side of the lid 3, with the third port 13 on the left side and the fifth port 15 on the right side. The fourth port 14 is located on the rear side of the lid 3 and is approximately in the center.

[0028] Of these, the third port 13 is a port through which air flows to measure pressure, and a transducer is connected to its 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 with an openable / closable clip is connected to its upper end. The fifth port 15 is a port for injecting chemicals as needed, and a chemical injection line 25 is connected to its upper end. It is possible to omit these ports, and it is also possible to add additional ports.

[0029] 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 bottom of the housing. A mixed fluid line 26 is connected to this outlet port, and the mixed fluid consisting of blood and replacement fluid mixed in the chamber space 2 is discharged through the outlet port.

[0030] In this embodiment, the case in which blood is introduced from the first port 11 and replacement fluid is introduced from the second port 12 is illustrated as described above, but it is not limited to this. Conversely, replacement fluid may be introduced from the first port 11 and blood from the second port 12. However, when blood is introduced from the first port 11 and replacement fluid is introduced from the second port 12 as described above, it is possible to suppress the coagulation of blood by exposing it to the air at the top of the chamber space 2. Furthermore, the use and arrangement of the third port 13, fourth port 14, and fifth port 15 are not limited to those described above, and other uses and arrangements may be adopted.

[0031] [Regarding the protruding section] As shown in Figures 1 to 3, the upper end of the chamber body 10 is provided with protruding portions 30 that project radially outward from the outer circumferential surface of the chamber body 10, that is, outward on both the left and right sides. Figure 4 is a longitudinal cross-sectional view of the mixing chamber taken along the line IV-IV in Figure 3. The cross-sectional surface along the line VI-VI passes through the left and right protruding portions 30 and is perpendicular to the front-to-back direction. The following explanation will refer to Figures 1 to 4.

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

[0033] The protruding portions 30 project outward to the left and right from the upper end of the small-diameter outer surface 43 of the chamber body 10. In other words, the protruding portions 30 are provided at opposing left and right positions on either side of the axis A0 of the chamber body 10.

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

[0035] Furthermore, as shown in Figures 2 and 4, the vertical thickness dimension D1 of the protruding portion 30 is greater than or equal to the thickness dimension D2 of the lid 3. In particular, the outer end portion 33 of the protruding portion 30, which is furthest from the small diameter outer peripheral surface 43, also has a vertical thickness dimension of greater than or equal to the thickness dimension D2 of the lid 3 (more preferably greater than the thickness dimension D2 of the lid 3). This provides the protruding portion 30 with a predetermined strength, thereby preventing situations where the protruding portion 30 breaks and the packaging bag is damaged and torn at the point of breakage.

[0036] As shown in Figure 3, the protruding portion 30 protrudes triangularly to the left and right from the lid 3 when viewed from above, and has a shape that smoothly connects with the contour of the lid 3. Specifically, the lid 3 has a circular contour that matches the upper end of the chamber body 10. The contour of the right protruding portion 30 is formed by tangents drawn to the right from the front right position and the rear right position of the circular outer surface of the lid 3. Similarly, the contour of the left protruding portion 30 is formed by tangents drawn to the left from the front left position and the rear left position of the circular outer surface of the lid 3. In addition, the outer end portions 33 located at the top of each of the left and right protruding portions 30 have an arc-shaped contour when viewed from above.

[0037] Since this protruding portion 30 is provided on the small-diameter outer surface 43, it does not overlap with the chamber space 2 when viewed in plan along the axis A0 (see Figure 4). The gate of the mold is connected to a predetermined position on the upper surface 31 of this protruding portion 30 during injection molding. Therefore, this upper surface 31 has a gate connection mark, or more specifically, a trace (gate connection mark) 34 left after removing the hardened resin inside the gate after demolding. Accordingly, the gate connection mark 34 is also provided in a position that does not overlap with the chamber space 2 when viewed in plan. Note that the chamber space 2 may be configured to be enlarged at the large-diameter outer surface 41, in which case part or all of the protruding portion 30 may overlap with the enlarged portion of the chamber space 2 at the large-diameter outer surface 41 when viewed in plan. The gate connection mark 34 forms a concave depression relative to the upper surface 31 of the protruding portion 30. As shown in Figure 3, it has a circular shape in plan view, and as shown in Figure 4, it has an isosceles trapezoidal shape in cross-section, with the lower base being smaller than the upper base. This concave shape of the gate connection mark 34 allows the resin injected into the mold and bounced off the lower surface 31 to flow stably, and also prevents burrs from protruding from the upper surface 31 when the resin at the gate portion is removed after demolding. However, the shape of the gate connection mark 34 is not limited to this concave shape; for example, it may be flat or convex.

[0038] As described above, the mixing chamber 1 is equipped with an overhang 30, and a gate connection mark 34 is provided on the overhang 30. This prevents the airtightness of the chamber space 2 from being compromised even if defects such as pinholes occur in the resin forming the mixing chamber 1 when the resin solidified at the gate is removed after demolding. In particular, since the gate connection mark 34 is provided on the overhang 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 leading to the chamber space 2.

[0039] Furthermore, the protruding sections 30 are provided at opposing left and right positions on either side of the axis A0 of the chamber body 10. This allows a gate to be connected to each of the two protruding sections 30, and resin to be injected from each gate. In this case, the amount of resin injected from each gate can be reduced, so the gate can be made smaller in diameter, and the defects in the protruding sections can be kept to a minimum. Note that the number of protruding sections 30 provided on the chamber body 10 is not limited to two. For example, there may be only one protruding section 30, or there may be three or more, and if multiple are provided, it is preferable to arrange them at equal intervals around the axis A0.

[0040] [Regarding Port 1 and Port 2] As shown in Figures 1 and 2, the first port 11 extends from the front circumferential portion of the chamber body 10 in one of the left and right tangential directions intersecting the axis A0 (left direction in the figures). The second port 12, located above the first port 11, also extends from the front circumferential portion of the chamber body 10 in one of the left and right tangential directions intersecting the axis A0 (left direction in the figures). Therefore, the two protruding portions 30 described above are spaced apart from the axis A0 in the direction of extension of the first port 11 and the second port 12 (left and right directions). The connection points of the first port 11 and the second port 12 to the chamber body 10 are the large-diameter outer surface 41 of the outer surface 40 of the chamber body 10.

[0041] Figure 5 is a view from below of a cross-section of the mixing chamber 1 cut by a plane perpendicular to the axis A0, where (A) is a cross-sectional view in the plane passing through the first port 11 (VA-VA plane), and (B) is a cross-sectional view in the plane passing through the first port 12 (VB-VB plane). The VA-VA plane is the plane containing the axis A1 of the first port 11, and the VB-VB plane is the plane containing the axis A2 of the second port 12.

[0042] As shown in Figure 5(A), the inner circumferential surface 50 of the first port 11 has, in order from the left (upstream) opening end, a guide surface 51, an inner fitting surface 52, and an introduction surface 53. The guide surface 51 has an inner surface shape that narrows in diameter from the opening end toward the inward (downstream) side, and guides the connector of the blood line 21 (see Figure 1) when it is connected to the connector. The inner fitting surface 52 fits onto the connector of the blood line 21 guided by the guide surface 51, connecting the blood line 21 and the mixing chamber 1. The introduction surface 53 defines a flow path that guides 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 guide surface 51 and is substantially constant along its 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 opposite downstream end opens at the inner circumferential surface 45 (more specifically, the small-diameter inner circumferential surface 47) of the chamber body 10. The inner circumferential surface 50, consisting of the guide surface 51, the inner fitting surface 52, and the introduction surface 53, is formed coaxially with respect to the axis A1. Furthermore, this axis A1 is eccentric to a position that does not intersect the axis A0 of the chamber body 10 in a plan view, and in this embodiment, it is tangent to the inner circumferential surface 45 (small-diameter inner circumferential surface 47) of the chamber space 2.

[0044] Incidentally, a portion of the downstream part of the inlet surface 53 forms a curved surface that curves with respect to the extension direction of the axis A1. More specifically, as shown in Figure 5(A), the wall portion of the first port 11 has a proximal side wall portion 54 that is close to the axis A0 and a distal side wall portion 55 that is far from the axis A0, on the opposite side of the axis A1. Of these, a curved surface 53a is formed in the downstream portion of the inlet surface 53, which is the inner circumferential surface of the distal side wall portion 55. The contour of this curved surface 53a, as shown in the cross-section in Figure 5(A), curves so that as you move from the upstream end to the downstream end, it changes direction from along the axis A1 to towards the axis A0 (in Figure 5(A), from the right to the right and diagonally backward). The inner circumferential surface of the proximal side wall portion 54 is straight 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, the contour of the connecting portion 56 in a cross section perpendicular to the axis A0 (see Figure 5(A)) and the contour in a cross section including the axis A0 are both arc-shaped. Also, as shown in Figure 5(A), the thickness dimension D3 of the connecting portion 56 gradually decreases as it moves from the connection point of the connecting portion 56 with the distal side wall portion 55 (see the position of plane P1 in the figure) towards the connection point of the connecting portion 56 with the chamber body 10 (see the position of plane P2 in the figure). Furthermore, in the cross section shown in Figure 5(A), the contour of the outer surface of the connecting portion 56 is an arc shape with a larger diameter than the contour of the curved surface 53a of the first port 11.

[0046] The range of the connecting portion 56 is from the plane P1 containing the axis A0, passing through the downstream end of the inner circumferential surface 50 of the distal side wall portion 55 of the first port 11, to the point where the gradual decrease in thickness dimension D3 ends (plane P2 in Figure 5(A)). Also, as shown in Figures 1 and 2, when viewed from the front, the connecting portion 56 has a tapered contour shape in which the vertical dimension gradually decreases towards the right side (downstream side of the first port 11). More specifically, the connecting portion 56 has a contour shape formed by combining an upper convex arc and a lower convex arc from above and below, with a pointed apex at the right end (the downstream end of the first port 11).

[0047] As explained above, the extension direction of the first port 11 and the second port 12 coincides with the separation direction of the two protruding portions 30 relative to the axis A0. As a result, the relative positional relationship between each protruding portion 30 and the first port 11 and the second port 12 is similar. This allows for equalization of the amount of resin injected (injection pressure) into the gates connected to each protruding portion 30, enabling each gate to be made smaller in diameter and minimizing the defects that occur in the protruding portions 30.

[0048] Furthermore, in the cross-section (VA-VA plane) of the first port 11, which is cut by a plane that includes the axis A1 of the first port 11 and is perpendicular to the axis A0 of the chamber body 10, the contour of the connection portion 56 between the outer surface of the first port 11 and the outer surface of the chamber body 10 has a curved shape. As a result, in the first port 11, the fluidity of the resin flowing from the chamber body 10 to the first port 11 during injection molding is improved, and the resin flow within the mold becomes smoother. Consequently, the injection pressure of the resin during injection molding can be kept low.

[0049] Furthermore, the thickness dimension D3 of the connecting portion 56 in the above cross-section gradually decreases as it moves from the first port 11 toward the chamber body 10. In addition, the contour of the outer surface 56a of the connecting portion 56 has a larger diameter arc shape 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 has a tapered shape that gradually decreases toward the downstream side. As a result, the flow of resin when it flows from the chamber body 10 toward the first port 11 becomes smoother, and the injection pressure of the resin during injection molding can be suppressed.

[0050] Furthermore, the second port 12, located above the first port 11, has the same configuration as the first port 11 described above. The configuration of this second port 12 will also be explained below with reference to Figure 5(B).

[0051] As shown in Figure 5(B), the inner circumferential surface 60 of the second port 12 has, in order from the left (upstream) opening end, a guide surface 61, an inner fitting surface 62, and an introduction surface 63. The guide surface 61 has an inner surface shape that narrows in diameter from the opening end toward the inward (downstream) side, and guides the connector of the replenishment fluid line 22 (see Figure 1) when connecting to the connector. The inner fitting surface 62 fits onto the connector of the replenishment fluid line 22 guided by the guide surface 61, connecting the replenishment fluid line 22 to the mixing chamber 1. The introduction surface 63 defines a flow path that guides the blood flowing through the connected replenishment 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 along its 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 opposite downstream end opens at the inner circumferential surface 45 (more specifically, the small-diameter inner circumferential surface 47) of the chamber body 10. The inner circumferential surface 60, consisting of the guide surface 61, the inner fitting surface 62, and the introduction surface 63, is formed coaxially with respect to the axis A2. Furthermore, this axis A2 is eccentric to a position that does not intersect the axis A0 of the chamber body 10 in a plan view, and in this embodiment, it is tangent to the inner circumferential surface 45 (small-diameter inner circumferential surface 47) of the chamber space 2.

[0053] Incidentally, a portion of the downstream part of the inlet surface 63 forms a curved surface that curves with respect to the extension direction of the axis A2. More specifically, as shown in Figure 5(B), the wall portion of the second port 12 has a proximal side wall portion 64 that is close to the axis A0, and a distal side wall portion 65 that is far from the axis A0, on the opposite side of the axis A2. Of these, a curved surface 63a is formed in the downstream portion of the inlet surface 63, which is the inner circumferential surface of the distal side wall portion 65. The contour of this curved surface 63a, as shown in the cross-section in Figure 5(B), curves so that as you move from the upstream end to the downstream end, it changes direction from along the axis A2 to towards the axis A0 (in Figure 5(B), from the right to the right and diagonally backward). The inner circumferential surface of the proximal side wall portion 64 is straight 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 is curved. More specifically, the contour of the connecting portion 66 in a cross section perpendicular to the axis A0 (see Figure 5(B)) and the contour in a cross section including the axis A0 are both arc-shaped. Also, as shown in Figure 5(B), the thickness dimension D4 of the connecting portion 66 gradually decreases as it moves from the connection point of the connecting portion 66 with the distal side wall portion 65 (see the position of plane P3 in the figure) towards the connection point of the connecting portion 66 with the chamber body 10 (see the position of plane P4 in the figure). Furthermore, in the cross section shown in Figure 5(B), the contour of the outer surface of the connecting portion 66 is an arc shape with a larger diameter than the contour of the curved surface 63a of the second port 12.

[0055] The range of the connecting portion 66 extends from the plane P3 containing axis A0, passing through the downstream end of the inner circumferential surface 60 of the distal side wall portion 65 of the second port 12, to the point where the gradual decrease in thickness dimension D4 ends (plane P4 in Figure 5(B)). Furthermore, as shown in Figures 1 and 2, when viewed from the front, the connecting portion 66 has a tapering contour shape in which the vertical dimension decreases as it moves to the right (downstream side of the second port 12). More specifically, the connecting portion 66 has a contour shape formed by combining an upper convex arc and a lower convex arc from above and below, with a pointed apex at the right end (the downstream end of the second port 12). Moreover, as shown in Figure 3, the protrusion dimension of the connecting portion 66 from the circumferential surface of the chamber body 10 gradually decreases as it moves downstream. This is also true for the connecting portion 56 of the first port 11 described above.

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

[0057] The configuration of the second port 12 and its vicinity as described above also produces the same effects as those described for the configuration of the first port 11 and its vicinity, but the explanation is omitted here. In this embodiment, as described above, both the first port 11 and the second port 12 have similar configurations, and in particular, a configuration in which connecting portions 56, 66 with curved contours is given as an example, but it is not limited to this. 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 of 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 Symbols]

[0059] 1. Mixing chamber 2 Chamber Space 3 Lid 10 Chamber body 11 Port 1 12 Port 2 30 Protruding section 56. Connecting part 66 Connecting part Axial axis of the A0 chamber body

Claims

1. A mixing chamber provided in a blood circuit for hemodialysis, A cylindrical chamber body having a chamber space inside, A first port is provided on the side of the chamber body for guiding the first liquid into the chamber space, The chamber body is provided with a second port located on the side of the chamber body, adjacent to the first port, which guides the second liquid into the chamber space, The first port and the second port extend from the periphery of the chamber body in a direction intersecting the axis of the chamber body, In a first cross-section of at least one of the first and second ports, which is cut by a plane that includes the axis of the port and is perpendicular to the axis of the chamber body, the contour of the connection portion between the outer surface of the port and the outer surface of the chamber body is curved. In the first cross-section, the shape of the outer surface of the connecting portion and the shape of the inner surface of the downstream end of the port are different, and the thickness dimension of the connecting portion gradually decreases as it moves downstream from the port to the chamber body. Mixing chamber.

2. The dimensions of the connecting portion in the direction along the axis are tapered, gradually decreasing towards the downstream side, and the downstream end has a pointed top in the downstream direction. A mixing chamber according to claim 1.

3. The connecting portion has an arc shape in both the outer contour of the first cross-section and the outer contour of the second cross-section obtained by cutting through a plane containing the axis of the chamber body. A mixing chamber according to claim 1.

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