JP7647755B2 - Mixing Chamber - Google Patents

Description

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

Hemodiafiltration (HDF) is one of the dialysis treatment methods. 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 dialysis fluid, and filtration is also performed to remove many waste products from the blood, from small to large molecular weights. In the blood circuit for this type of hemodiafiltration, dialysis fluid is replenished to the blood before it is introduced into the dialyzer, or to the blood after it is drawn out from the dialyzer, in order to replenish the water that is lost from the blood by filtration.

A mixing chamber, as shown in Patent Document 1, is known as a configuration for replenishing blood with dialysis fluid in a blood circuit. This mixing chamber has a vertically long cylindrical body, with a port provided at the top for connecting a pressure measuring transducer and two ports provided at the side for introducing blood and dialysis fluid, respectively.

Such mixing chambers are made of resin and can be formed by injection molding. In injection molding, the resin material is melted by heat and discharged from a nozzle and injected into the space inside the mold through injection passages such as a spool, runner, and gate. After cooling and solidifying the resin, the mold is opened and the molded product, which is integrated with the branch-like resin (hereafter referred to as "branches") that has solidified inside the injection passages, is removed. The branches are then cut and removed at the base of the gate (the connection between the gate and the molded product) to obtain a single molded product.

International Publication No. 2016/152934

However, it has been newly discovered that when there are multiple ports on the side as in Patent Document 1, when the branch is removed, a large defect occurs at the connection with the molded product, the thickness of the part where the defect occurs becomes small, and depending on the pressure difference between the inside and outside of the chamber, the desired airtightness may not be ensured. That is, in the case of a chamber having two ports on the side of the main body as in Patent Document 1, the volume of the chamber body is larger than in a configuration with one port, and the amount of resin injected is larger. For this reason, it is necessary to increase the flow path cross-sectional area of the gate, and a branch with a large diameter is formed, and when the branch is removed, a large defect occurs in the chamber body. As a result, there is a possibility that airtightness problems such as pinholes will occur during manufacturing or use.

In addition, 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, and there is also the problem that the connecting part between the port and the housing is deformed. In other words, when there are two ports on the side of the main body, the chamber volume increases and the number of places where the resin needs to flow sideways increases, so the resin injection pressure tends to increase. If the injection pressure is high, the resin will get into the gaps in the parting surfaces of the mold, worsening the demolding properties and making it more likely to deform during demolding. As a result, the connecting flow path between the port and the chamber may deform, causing unintended flow when blood is flowed.

Therefore, the objective of this disclosure is to provide an injection-molded mixing chamber that can achieve at least one of the following objectives: ensuring airtightness and suppressing deformation of the connecting flow path.

The mixing chamber of the present disclosure is a mixing chamber provided in a blood circuit for hemodialysis, and comprises a cylindrical chamber body having a chamber space therein, a first port provided on the side of the chamber body for directing a first liquid to the chamber space, and a second port provided on the side of the chamber body adjacent to the first port for directing a second liquid to the chamber space, and one end of the chamber body is provided with a protruding portion that protrudes radially outward from the outer peripheral surface of the chamber body, and the protruding portion has a gate connection mark that is a gate connection mark that a mold has during injection molding.

As a result, by connecting a gate to the protruding portion and performing injection molding, even if some damage occurs when removing the resin that has solidified at the gate, the airtightness of the chamber body is not compromised.

The protrusion portion may also have a portion at the one end that does not overlap with the chamber space when viewed along the axial direction of the chamber body.

This prevents a large defect from reaching the chamber space, even if the defect is large when removing the solidified resin at the gate.

The protrusions may also be provided at opposing positions across the axis of the chamber body.

This allows a gate to be connected to each of the multiple protrusions and resin to be injected from each gate. In this case, residual stress in the resin in the circumferential direction of the chamber is reduced, suppressing deformation of the chamber including the first and second ports.

In addition, the first port and the second port may extend from the periphery of the chamber body in a tangential direction intersecting the axis of the chamber body, and two of the protrusion portions may be provided spaced apart in the extension direction of the first port and the second port relative to the axis of the chamber body.

This makes the relative positional relationship between each protrusion and each port similar, making it possible to equalize the amount of resin injected (injection pressure) into the gates connected to each protrusion. As a result, residual stress is reduced, and deformation of the chamber including the first and second ports is suppressed.

The mixing chamber according to the present disclosure is a mixing chamber provided in a blood circuit for hemodialysis, and comprises a cylindrical chamber body having a chamber space therein, 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 alongside the first port for introducing a second liquid into the chamber space, the first port and the second port extending from the periphery of the chamber body in a direction intersecting the axis of the chamber body, and at least one of the first port and the second port has a contour of a connecting portion between the outer surface of the port and the outer surface of the chamber body that is curved in a cross section taken along a plane that includes the axis of the port and is perpendicular to the axis of the chamber body.

As a result, in ports with curved connecting sections, the fluidity of the resin improves when it flows from the chamber into the port during injection molding, allowing the resin to flow smoothly within the mold. As a result, the injection pressure of the resin during injection molding can be kept low, reducing the risk of deformation of the connecting flow path due to excessive injection pressure when demolding.

The thickness dimension of the connecting portion in the cross section may be gradually reduced from the port toward the chamber body. The contour of the connecting portion may be 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.

This allows the resin to flow smoothly from the wall of the port to the wall of the chamber body, reducing the injection pressure of the resin during injection molding.

The mixing chamber of the present disclosure can ensure airtightness or suppress an increase in resin injection pressure, thereby realizing a mixing chamber with excellent manufacturing stability.

FIG. 1 is a perspective view of a mixing chamber according to the present embodiment. FIG. 2 is a front view of the mixing chamber. FIG. 3 is a top view of the mixing chamber. FIG. 4 is a vertical cross-sectional view of the mixing chamber taken along line IV-IV in FIG. 5(A) is a cross-sectional view of the mixing chamber taken along line VA-VA in FIG. 2, and FIG. 5(B) is a cross-sectional view of the mixing chamber taken along line VB-VB in FIG. 2.

[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. The mixing chamber 1 is provided on a blood circuit for hemofiltration dialysis, for example. In the mixing chamber 1, the pressure of the introduced blood is measured, and a replacement fluid (dialysis fluid) is also introduced to be mixed with the blood in order to replenish the water lost from the blood during filtration.

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, one end (upper end) is closed by a lid 3, and the other end (lower end) is open. Five ports 11 to 15 are provided in the 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 discharging blood from the mixing chamber is formed at the lower end of the housing. 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 3, and a bottomed cylindrical housing is fixed to the upper end, or the mixing chamber 1 may be formed by opening one end (upper end) and the other end (lower end) and fixing a bottomed cylindrical housing to each end. The chamber body 10 may also be formed such that one end (upper end) and the other end (lower end) are closed by the lid 3.

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 liquid) to the chamber space 2, and the blood line 21 is connected to its upstream end. The second port 12 is a port that guides a replenishment liquid (second liquid) to be mixed with blood to the chamber space 2, and the replenishment liquid 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 of the axis A0 direction of the chamber body 10. 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 that intersects with the axial direction of the chamber body 10, and more specifically, extend in a tangential direction of the outer peripheral surface of the chamber body 10.

For the sake of convenience, the concepts of directions used in the following description are defined as follows. That is, in the direction of the axis A0 of the chamber body 10, the end side where the cover body 3 is provided is defined as "upper", and the other end side is defined as "lower". The side of the chamber body 10 where the first port 11 and the second port 12 are provided is defined as the "front" (front), and the opposite is defined as the "rear". Also, in the extension direction of the first port 11 and the second port 12, the direction in which the ports 11, 12 extend from the connection position of the ports 11, 12 with the chamber body 10 is defined as the "left", and the opposite is defined as the "right".

The third port 13, fourth port 14, and fifth port 15 are protruding from the lid 3 at the upper end of the chamber body 10, all opening upward. The third port 13 and 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, approximately in the center from left to right.

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 equipped with an openable and closable clip is connected to its upper end. The fifth port 15 is a port for appropriately injecting medicines, etc., and a medicine injection line 25 is connected to its upper end. It is possible to eliminate these ports, or to provide additional ports.

The opening at the bottom of the chamber body 10 forms a fitting into which a cylindrical housing with a bottom is fitted, and an outlet port is provided at the bottom of the housing. A mixed liquid line 26 is connected to this outlet port, and the mixed liquid consisting of blood and replacement liquid mixed in the chamber space 2 is discharged through the outlet port.

In this embodiment, as described above, blood is introduced from the first port 11 and replacement fluid is introduced from the second port 12, but this is not limited to the above. 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 prevent the blood from being exposed to the air at the top of the chamber space 2 and coagulating. Furthermore, 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.

[About the protruding parts]
As shown in Figures 1 to 3, the upper end of the chamber body 10 is provided with overhanging parts 30 that protrude radially outward from the outer circumferential surface of the chamber body 10, i.e., protrude outward in both the left and right directions. Figure 4 is a vertical cross-sectional view of the mixing chamber taken along line IV-IV in Figure 3. The cut surface taken along line VI-VI is a plane that passes through the left and right overhanging parts 30 and is perpendicular to the front-rear direction. The following description will be given with reference to Figures 1 to 4.

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 near 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 step 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. The large diameter inner peripheral surface 46 forms a fitting portion into which the upper end opening of the housing is fitted.

The protruding portions 30 protrude outward to the left and right from the upper end of the small diameter outer circumferential surface 43 of the chamber body 10. In other words, the protruding portions 30 are provided at left and right positions facing each other across the axis A0 of the chamber body 10.

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 forms an inclined surface that slopes upward from the connection point with the small diameter outer peripheral surface 43 toward the left and right. Therefore, the vertical thickness dimension D1 of the protruding portion 30 (the distance between the upper surface 31 and the lower surface 32) becomes smaller from the connection point with the small diameter outer peripheral surface 43 toward the left and right, forming an overall tapered shape when viewed from the front (see also FIG. 2).

2 and 4, the vertical thickness dimension D1 of the protruding portion 30 is equal to or greater than the thickness dimension D2 of the lid body 3. In particular, the vertical thickness dimension of the outer end portion 33 of the protruding portion 30, which is the furthest outward from the small diameter outer circumferential surface 43, is equal to or greater than the thickness dimension D2 of the lid body 3 (more preferably, greater than the thickness dimension D2 of the lid body 3). This provides the protruding portion 30 with a predetermined strength, thereby preventing the protruding portion 30 from breaking and damaging the packaging bag at the damaged location, resulting in tearing.

As shown in FIG. 3, the overhanging portion 30 protrudes in a triangular shape on the left and right sides relative to the lid body 3 when viewed in a plan view, and has a shape that smoothly connects to the contour of the lid body 3. Specifically, the lid body 3 has a circular contour that matches the upper end of the chamber body 10. The contour of the right overhanging portion 30 is formed by tangents drawn to the right from the right front position and the right rear position of the circular outer peripheral surface of the lid body 3. Similarly, the contour of the left overhanging portion 30 is formed by tangents drawn to the left from the left front position and the left rear position of the circular outer peripheral surface of the lid body 3. The outer ends 33 located at the tops of the left and right overhanging portions 30 have an arc-shaped contour when viewed in a plan view.

Since such a protruding portion 30 protrudes from the small diameter outer peripheral surface 43, it does not overlap with the chamber space 2 when viewed in a plane along the axis A0 (see FIG. 4). A 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, more specifically, a mark (gate connection mark) 34 where the resin hardened in the gate was removed after demolding. Therefore, the gate connection mark 34 is also provided at a position that does not overlap with the chamber space 2 when viewed in a plane. Note that the chamber space 2 may be configured to have an expanded diameter at the large diameter outer peripheral portion 41, for example, and in that case, a part or all of the protruding portion 30 may overlap with the part of the chamber space 2 that is expanded at the large diameter outer peripheral portion 41 when viewed in a plane. The gate connection mark 34 forms a concave depression on the upper surface 31 of the protruding portion 30, and has a circular shape in a plan view as shown in Fig. 3, and has an isosceles trapezoid shape with a lower base smaller than the upper base in a cross-sectional view as shown in Fig. 4. By forming the gate connection mark 34 in this concave shape, the resin that is injected into the mold and bounces off the lower surface 31 can be stably flowed, and burrs can be prevented from protruding from the upper surface 31 when the resin in the gate portion is removed after demolding. However, the shape of the gate connection mark 34 is not limited to this concave shape, and may be, for example, flat or convex.

As described above, the mixing chamber 1 has a protruding portion 30, and the protruding portion 30 is provided with a gate connection mark 34. This makes it possible to prevent the airtightness of the chamber space 2 from being impaired even if a defect such as a pinhole occurs 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 in the protruding portion 30 that does not overlap with the chamber space 2 when viewed in the direction of the axis A0, the formation of a through hole leading to the chamber space 2 can be avoided even if a pinhole occurs in the gate connection mark 34.

The protruding portions 30 are provided on the left and right sides facing each other across the axis A0 of the chamber body 10. This allows a gate to be connected to each of the two protruding portions 30, and resin can be injected from each gate. In this case, the amount of resin injected from one gate can be reduced, allowing the gate to have a narrow diameter, and reducing defects in the protruding portion. The number of protruding portions 30 provided on 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 protruding portions 30. If multiple protruding portions 30 are provided, they are preferably arranged at equal intervals around the axis A0.

[Regarding the first port and the second port]
1 and 2, the first port 11 extends from the front periphery of the chamber body 10 in one of the left and right tangential directions intersecting with the axis A0 (leftward in the figure). The second port 12 located above the first port 11 also extends from the front periphery of the chamber body 10 in one of the left and right tangential directions intersecting with the axis A0 (leftward in the figure). Therefore, the above-mentioned two protruding parts 30 are provided at a distance from the axis A0 in the extension direction (left-right direction) of the first port 11 and the second port 12. The connection positions of the first port 11 and the second port 12 to the chamber body 10 are the large-diameter outer circumferential surface 41 of the outer circumferential surface 40 of the chamber body 10.

Figure 5 shows a cross section of the mixing chamber 1 cut at a plane perpendicular to the axis A0, viewed from below, where (A) is a cross section in a plane (VA-VA plane) passing through the first port 11, and (B) is a cross section in a plane (VB-VB plane) passing through the first port 12. The VA-VA plane is a plane that includes the axis A1 of the first port 11, and the VB-VB plane is a plane that includes the axis A2 of the second port 12.

As shown in Figure 5 (A), the inner peripheral surface 50 of the first port 11 has, in order from the left (upstream) opening end, a guide surface 51, an internal fitting surface 52, and an introduction surface 53. The guide surface 51 has an inner surface shape that tapers inward (downstream) from the opening end, and guides the connector of the blood line 21 (see Figure 1) when it is connected to the connector. The internal fitting surface 52 fits onto the connector of the blood line 21 guided by the guide surface 51, connecting the blood line 21 to the mixing chamber 1. The introduction surface 53 defines a flow path that guides blood flowing through the connected blood line 21 to the chamber space 2.

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 almost 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 to the inner peripheral surface 45 (more specifically, the small diameter inner peripheral surface 47) of the chamber body 10. The inner peripheral surface 50 consisting of these guide surface 51, inner fitting surface 52, and introduction surface 53 is formed coaxially with the axis A1. In addition, this axis A1 is eccentric to a position that does not intersect with the axis A0 of the chamber body 10 in a plan view, and in this embodiment, forms a tangent to the inner peripheral surface 45 (small diameter inner peripheral surface 47) of the chamber space 2.

By the way, a part of the downstream part of the introduction surface 53 forms a curved surface curved with respect to the extension direction of the axis A1. More specifically, as shown in FIG. 5(A), the wall part of the first port 11 has a proximal side wall part 54 close to the axis A0 and a distal side wall part 55 far from the axis A0 across the axis A1. A curved surface 53a is formed on the downstream part of the introduction surface 53, which is the inner peripheral surface of the distal side wall part 55. This curved surface 53a is curved so that the outline represented by the cross section of FIG. 5(A) turns from the direction along the axis A1 to the direction facing the axis A0 (from the right direction to the right diagonally backward) as it moves from the upstream end to the downstream end. The inner peripheral surface of the proximal side wall part 54 is linear from the upstream end to the downstream end.

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 FIG. 5A) and the contour of the cross section including the axis A0 are both arc-shaped. Also, as shown in FIG. 5A, the thickness dimension D3 of the connecting portion 56 gradually decreases 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) toward 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 FIG. 5A, 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.

The range of the connecting portion 56 is from a plane P1 that passes through the downstream end of the inner peripheral surface 50 of the distal side wall portion 55 of the first port 11 and includes the axis A0 to the point where the gradual decrease in the thickness dimension D3 ends (plane P2 in FIG. 5A). As shown in FIGS. 1 and 2, the connecting portion 56 when viewed from the front has a tapered contour shape in which the vertical dimension gradually decreases toward the right side (the downstream side of the first port 11). More specifically, the connecting portion 56 has a contour shape that combines an upper convex arc and a lower convex arc from above and below, and the right end (the end on the downstream side of the first port 11) forms a pointed apex.

As described above, the extension direction of the first port 11 and the second port 12 coincides with the direction of separation of the two protrusions 30 from the axis A0. This results in a similar relative positional relationship between each protrusion 30 and the first port 11 and the second port 12. This makes it possible to equalize the amount of resin injected (injection pressure) into the gates connected to each protrusion 30, allowing each gate to have a small diameter, and minimizing defects that may occur in the protrusion 30.

In addition, in a cross section (VA-VA plane) taken along 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 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. This improves the fluidity of the resin flowing from the chamber body 10 into the first port 11 during injection molding, and smooths the flow of the resin within the mold. As a result, the injection pressure of the resin during injection molding can be kept low.

The thickness dimension D3 of the connecting portion 56 in the above cross section gradually decreases from the first port 11 toward the chamber body 10. The contour of the outer surface 56a of the connecting portion 56 is 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. Furthermore, the vertical dimension of the connecting portion 56 is a tapered shape that gradually decreases toward the downstream side. This allows the resin to flow smoothly from the chamber body 10 into the first port 11, and suppresses the injection pressure of the resin during injection molding.

The second port 12 located above the first port 11 has a similar configuration to the first port 11 described above. The configuration of the second port 12 will also be described below with reference to FIG. 5(B).

As shown in FIG. 5B, the inner peripheral surface 60 of the second port 12 has, in order from the left (upstream) opening end, a guide surface 61, an internal fitting surface 62, and an introduction surface 63. The guide surface 61 has an inner surface shape that tapers inward (downstream) from the opening end, and guides the connector of the replenishment liquid line 22 (see FIG. 1) when it is connected to the connector. The internal fitting surface 62 fits onto the connector of the replenishment liquid line 22 guided by the guide surface 61, connecting the replenishment liquid line 22 to the mixing chamber 1. The introduction surface 63 defines a flow path that guides blood flowing through the connected replenishment liquid line 22 to the chamber space 2.

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 almost 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 to the inner peripheral surface 45 (more specifically, the small diameter inner peripheral surface 47) of the chamber body 10. The inner peripheral surface 60 consisting of these guide surface 61, inner fitting surface 62, and introduction surface 63 is formed coaxially with the axis A2. In addition, this axis A2 is eccentric to a position that does not intersect with the axis A0 of the chamber body 10 in a plan view, and in this embodiment, forms a tangent to the inner peripheral surface 45 (small diameter inner peripheral surface 47) of the chamber space 2.

By the way, a part of the downstream part of the introduction surface 63 forms a curved surface curved with respect to the extension direction of the axis A2. More specifically, as shown in FIG. 5(B), the wall part of the second port 12 has a proximal side wall part 64 close to the axis A0 and a distal side wall part 65 far from the axis A0 across the axis A2. A curved surface 63a is formed on the downstream part of the introduction surface 63, which is the inner peripheral surface of the distal side wall part 65. This curved surface 63a is curved so that the outline represented by the cross section in FIG. 5(B) turns from the direction along the axis A2 to the direction facing the axis A0 (from the right direction to the right diagonally backward) as it moves from the upstream end to the downstream end. The inner peripheral surface of the proximal side wall part 64 is linear from the upstream end to the downstream end.

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 FIG. 5B) and the contour of the cross section including the axis A0 are both arc-shaped. Also, as shown in FIG. 5B, the thickness dimension D4 of the connecting portion 66 gradually decreases 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) toward 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 FIG. 5B, 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.

The range of the connecting portion 66 is from the plane P3 that passes through the downstream end of the inner peripheral surface 60 of the distal side wall portion 65 of the second port 12 and includes the axis A0 to the point where the gradual decrease in the thickness dimension D4 ends (plane P4 in FIG. 5B). As shown in FIGS. 1 and 2, the connecting portion 66 when viewed from the front has a tapered contour shape in which the vertical dimension becomes smaller toward the right side (the downstream side of the second port 12). More specifically, the connecting portion 66 has a contour shape that combines an upper convex arc and a lower convex arc from above and below, and the right end (the downstream end of the second port 12) forms a pointed apex. Furthermore, 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 toward the downstream side. This is also the same for the connecting portion 56 of the first port 11 described above.

Also, as shown in Figure 4, when comparing the downstream opening of the first port 11 with the downstream opening of the second port 12, the lower first port 11 is slightly larger in both vertical and horizontal dimensions. On the other hand, when comparing the curved surfaces 53a, 63a, the upper second port 12 is slightly larger in horizontal dimensions than the first port. However, this difference between the first port 11 and the second port 12 is not essential, and can be set appropriately taking into account the flow rate of the liquid flowing through each port and the efficiency of mixing in the chamber space 2, etc.

The above-mentioned configuration of the second port 12 and its vicinity also provides the same effects as those described for the first port 11 and its vicinity, but the description thereof will be omitted here. In this embodiment, the first port 11 and the second port 12 both have the same configuration as described above, and in particular, a configuration including connecting portions 56, 66 with curved contours has been exemplified, but this 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.

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

Reference Signs List 1 Mixing chamber 2 Chamber space 3 Lid 10 Chamber body 11 First port 12 Second port 30 Projection 56 Joint portion 66 Joint portion A0 Axial center of chamber body

Claims (3)

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;
a protruding portion protruding radially outward from an outer circumferential surface of the chamber body is provided at one end of the chamber body,
The protruding portion has a gate connection mark which is a gate connection mark of a mold at the time of injection molding.
Mixing chamber. the first port and the second port extend from a periphery of the chamber body in a tangential direction intersecting an axis of the chamber body,
the protruding portion is provided in two portions spaced apart from each other in an extension direction of the first port and the second port with respect to an axis of the chamber body;
2. The mixing chamber of claim 1. 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 is curved in a cross section taken along a plane that includes an axis of the port and is perpendicular to an axis of the chamber body.
2. The mixing chamber of claim 1 .

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