Diaphragm-type pressure measurement chamber

Abstract

When a pressure measurement chamber 1 is viewed along a first direction in which a first chamber (13a) and a second chamber (13b) overlap, the axis (A1) of a first port (P1) is offset from the center (CP) of a chamber space (13) so as to divide the chamber space (13) into a first region and a second region that is larger than the first region and intersects an inner surface (22) of a housing (14), a second port (P2) is connected to the second region, and the axis (A1) of the first port (P1) and the axis (A2) of the second port (P2) are separated from each other and parallel or the axis (A1) of the first port (P1) and the axis (A2) of the second port (P2) are slanted toward each other and intersect outside the chamber space (13).

Description

Diaphragm pressure measurement chamber

[0001] The present invention relates to a diaphragm-type pressure measuring chamber for measuring the pressure of blood flowing through a blood circuit.

[0002] Blood purification therapy involves extracorporeally circulating a patient's blood and purifying it during circulation. Dialysis therapy is one example of this type of therapy. In dialysis therapy, blood drawn from a patient is introduced into a dialyzer, where unwanted components in the blood are replaced with useful components in a dialysate and filtered. The treated blood is then returned to the patient. In dialysis therapy, blood pressure is measured at various points in the blood circuit to prevent damage to useful blood cells and blood aggregation. For example, a diaphragm-type pressure vessel (pressure pod), as described in Patent Document 1, has been proposed for measuring pressure at various points in the blood circuit.

[0003] U.S. Patent No. 8,092,414

[0004] The pressure vessel (12) in Patent Document 1 has two ports (30, 32) communicating with the internal space, and each port (30, 32) is connected to a blood circuit. The two ports (30, 32) are arranged so that their axes are aligned, and the openings of the two ports (30, 32) are positioned directly opposite each other. Therefore, a portion of the blood that flows into the pressure vessel (12) from one port travels straight toward the opening and exits the pressure vessel (12) from the other port. However, blood that flows into the pressure vessel (12) from one port but travels in a direction different from the opening direction deviates from the flow toward the other port and is therefore likely to stagnate within the pressure vessel (12). Blood stagnation within the pressure vessel (12) is undesirable because it is prone to thrombus formation.

[0005] Therefore, an object of the present disclosure is to provide a diaphragm type pressure measurement chamber in which blood is less likely to stagnate in the internal space.

[0006] A diaphragm-type pressure measurement chamber according to a first aspect of the present disclosure comprises a housing having a chamber space therein, a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber, a first port connected to the housing and allowing blood to flow into the liquid chamber, and a second port extending in a direction away from the first port and connected to the housing and allowing blood to flow out of the liquid chamber; when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port is offset from the center of the chamber space and intersects with the inner surface of the housing so as to divide the chamber space into a first region and a second region larger than the first region; the second port is connected to the second region, and is configured so that the axis of the first port and the axis of the second port are spaced apart from each other and parallel to each other, or so that the axis of the first port and the axis of the second port are inclined to each other and intersect outside the chamber space.

[0007] In the chamber of the present disclosure, when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port intersects the inner surface of the housing away from the center of the chamber space, dividing the chamber space into a first region and a second region larger than the first region, and the second port is connected to the second region. This reduces blood stagnation within the liquid chamber. Specifically, because the inner surface of the housing is aligned with the axis of the first port, which is the center of the blood flow formed by the first port, blood tends to spread in a direction perpendicular to the axis of the first port. Furthermore, because the second port is connected to the second region, blood flowing in from the first port is easily drawn toward the second region. Therefore, when viewed from the first direction, blood flowing in from the first port tends to spread in a direction perpendicular to the axis of the first port. This expands the area in which blood is agitated within the liquid chamber compared to conventional devices, thereby reducing blood stagnation within the liquid chamber.

[0008] The chamber of the present disclosure is also configured so that the axis of the first port and the axis of the second port are spaced apart and parallel to each other, or so that the axis of the first port and the axis of the second port are inclined relative to each other and intersect outside the chamber space. This reduces the amount of blood flowing from the first port that is drawn into the second port before colliding with the inner surface of the housing opposite the first port. This reduces the strong flow along the straight line connecting the first and second ports and strengthens the flow that bypasses the straight line along the inner surface of the housing. The opening of the second port is preferably formed at a position where an imaginary line parallel to the axis of the first port and passing through the center of the chamber space intersects with the inner surface of the housing, or at a position on the inner surface of the housing farther from the first port than the imaginary line, as viewed from the first direction. Furthermore, the inner surface of the housing does not necessarily need to be formed with a guide portion, such as an axial guide portion, as described below.

[0009] A diaphragm-type pressure measurement chamber according to a second aspect of the present disclosure includes a housing having a chamber space therein, a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber, a first port connected to the housing and passing blood flowing into the liquid chamber, and a second port connected to the housing and passing blood flowing out of the liquid chamber, and when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port is oriented in the chamber so as to divide the chamber space into a first region and a second region larger than the first region. The second port is connected to the second region, and a guide portion having a stepped portion is formed on the inner surface of the housing. The guide portion has an upper guide portion that extends in the first direction toward the diaphragm. The upper guide portion is located above the lower end of the opening of the first port, and when viewed along the first direction, is formed between the axis of the first port and an imaginary line that is parallel to the axis of the first port and passes through the opening of the second port.

[0010] In the chamber of the present disclosure, when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port intersects the inner surface of the housing away from the center of the chamber space, dividing the chamber space into a first region and a second region larger than the first region, and the second port is connected to the second region. This reduces blood stagnation within the liquid chamber. Specifically, because the inner surface of the housing is aligned with the axis of the first port, which is the center of the blood flow formed by the first port, blood tends to spread in a direction perpendicular to the axis of the first port. Furthermore, because the second port is connected to the second region, blood flowing in from the first port is easily drawn toward the second region. Therefore, when viewed along the first direction, blood flowing in from the first port tends to spread in a direction perpendicular to the axis of the first port. This expands the area in the liquid chamber where blood is stirred compared to conventional devices, thereby reducing blood stagnation within the liquid chamber.

[0011] The chamber of the present disclosure is positioned above the lower end of the opening of the first port, and when viewed in the first direction, an upper guide portion is formed on the inner surface of the housing between the axis of the first port and an imaginary line parallel to the axis of the first port and passing through the opening of the second port. This facilitates upward flow of blood flowing along the inner surface of the housing from the first port, thereby reducing stagnation in the area near the edge of the diaphragm. Note that this guide portion can also be applied to a chamber in which the axis of the first port and the axis of the second port intersect within the chamber space, or to a chamber in which the first port, liquid chamber, and second port are arranged in this order to form a U-shape, thereby reducing stagnation in the area near the edge of the diaphragm.

[0012] Furthermore, the guide portion preferably includes a circumferential guide portion extending toward the opening of the second port when viewed from the first direction. However, the circumferential guide portion may be omitted, and the axial guide portion described below may also be omitted. For example, the guide portion may be formed only as an upper guide extending toward the diaphragm in the first direction on the axis of the first port. The upper guide portion may be connected to the circumferential guide portion, or may include the circumferential guide portion to guide blood both upward and circumferentially at the same time. Furthermore, in terms of height, it is particularly preferable for the upper guide portion to extend upward from the height position of the lower end of the opening of the first port to a height exceeding the axis of the first port. The axis of the first port is the center of the flow formed by the first port, and by extending the upper guide portion above the center of the flow formed by the first port, blood can be more efficiently guided upward. Furthermore, it is particularly preferable that the upper guide portion extends above the opening of the second port, in which case it is possible to generate a blood flow that bypasses the opening of the second port. The guide portion may be configured as a rib instead of a groove, but a concave shape is preferable because it is less likely to disperse the flow and can generate a strong flow.

[0013] A diaphragm-type pressure measurement chamber according to a third aspect of the present disclosure comprises a housing having a chamber space therein, a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber, a first port connected to the housing and allowing blood to flow into the liquid chamber to pass through, and a second port connected to the housing and allowing blood to flow out of the liquid chamber to pass through, wherein when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port is offset from the center of the chamber space and intersects with the inner surface of the housing so as to divide the chamber space into a first region and a second region larger than the first region, the second port is connected to the second region, a guide portion having a stepped portion is formed on the inner surface of the housing, and the guide portion has a circumferential guide portion located between the axis of the first port and an imaginary line that is parallel to the axis of the first port and passes through the opening of the second port, and extending from the axis of the first port in a direction approaching the imaginary line.

[0014] In the chamber of the present disclosure, when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port intersects the inner surface of the housing away from the center of the chamber space, dividing the chamber space into a first region and a second region larger than the first region, and the second port is connected to the second region. This reduces blood stagnation within the liquid chamber. Specifically, because the inner surface of the housing is aligned with the axis of the first port, which is the center of the blood flow formed by the first port, blood tends to spread in a direction perpendicular to the axis of the first port. Furthermore, because the second port is connected to the second region, blood flowing in from the first port is easily drawn toward the second region. Therefore, when viewed from the first direction, blood flowing in from the first port tends to spread in a direction perpendicular to the axis of the first port. This expands the area in the liquid chamber where blood is stirred compared to conventional devices, thereby reducing blood stagnation within the liquid chamber.

[0015] Furthermore, the chamber of the present disclosure uses a circumferential guide portion to direct blood flowing from the first port toward the second port, which is located off-axis from the first port. This prevents blood from dispersing in the direction opposite the second port, facilitating a strong flow toward the second port. This facilitates a flow that circulates around the housing, preventing blood from stagnating within the chamber space. This guide portion can also be applied to chambers in which the axes of the first and second ports intersect within the chamber space, or chambers in which the first port, liquid chamber, and second port are arranged in this order in a U-shape. The upper guide portion and axial guide portion may be omitted. The circumferential guide portion is preferably formed so as to be connected to the axis of the first port, which allows blood flowing from the first port to be efficiently directed circumferentially. The guide portion may be configured as a rib instead of a groove, but a concave shape is preferred because it reduces flow dispersion and generates a strong flow.

[0016] A diaphragm-type pressure measurement chamber according to a fourth aspect of the present disclosure comprises a housing having a chamber space therein, a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber, a first port connected to the housing and allowing blood to flow into the liquid chamber to pass through, and a second port connected to the housing and allowing blood to flow out of the liquid chamber to pass through, wherein when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port is offset from the center of the chamber space and intersects with the inner surface of the housing so as to divide the chamber space into a first region and a second region larger than the first region, the second port is connected to the second region, a guide portion having a stepped portion is formed on the inner surface of the housing, and the guide portion may have an axial guide portion extending from the first port in the axial direction of the first port when viewed from the first direction.

[0017] In the chamber of the present disclosure, when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port intersects the inner surface of the housing away from the center of the chamber space, dividing the chamber space into a first region and a second region larger than the first region, and the second port is connected to the second region. This reduces blood stagnation within the liquid chamber. Specifically, because the inner surface of the housing is aligned with the axis of the first port, which is the center of the blood flow formed by the first port, blood tends to spread in a direction perpendicular to the axis of the first port. Furthermore, because the second port is connected to the second region, blood flowing in from the first port is easily drawn toward the second region. Therefore, when viewed from the first direction, blood flowing in from the first port tends to spread in a direction perpendicular to the axis of the first port. This expands the area in the liquid chamber where blood is stirred compared to conventional devices, thereby reducing blood stagnation within the liquid chamber.

[0018] Furthermore, in the chamber of the present disclosure, the second port is located on the second region side, while the guide portion has an axial guide portion extending in the axial direction of the first port, thereby preventing a strong flow connecting the first port and the second port in a straight line. In other words, the flow direction of blood flowing from the first port into the liquid chamber of the chamber space can be directed toward the inner surface of the housing rather than the second port, making it easier for blood to flow along the inner surface of the housing. The guide portion may extend from the first port to the second port. In this case, the guide portion functions as a space-forming portion that defines a flow path from the first port to the second port. Therefore, even if a portion of the diaphragm bends downward to abut the inner surface of the housing, the flow path from the first port to the second port is not blocked. However, the guide portion does not have to function as a space-forming portion; a space-forming portion may be formed separately, or a space-forming portion may not be formed at all. Furthermore, the guide portion may not have an upper guide portion or a circumferential guide portion.

[0019] Furthermore, in the diaphragm-type pressure measurement chamber according to a fifth aspect of the present disclosure, in any of the first to fourth aspects, the minimum distance connecting an imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space and an imaginary line that is parallel to the axis of the second port and intersects with the center of the opening of the second port may be shorter than the minimum distance connecting an imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space and an imaginary line that is parallel to the axis of the second port and intersects with the center of the opening of the first port.

[0020] As a result, the opening of the first port is positioned farther from the center of the housing, making it easier for blood flowing in from the first port to flow along the inner wall of the housing. Meanwhile, the second port, which serves as the outlet, is positioned so that its axis is closer to the center of the housing, improving air purging from the chamber space. In other words, in the diaphragm-type pressure measurement chamber of the present disclosure, it is assumed that priming or treatment will be performed with the second port, which serves as the outlet, facing upward in the direction of gravity. In this case, air within the chamber space tends to accumulate at the top of the chamber space. Therefore, by positioning the opening of the second port closer to the center as described above, it becomes easier for air at the top of the chamber space to be discharged through the second port, improving air purging during priming.

[0021] Note that air escapes most easily when the opening of the second port is located on an imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space. On the other hand, the farther the second port is from the first port than the imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space, the more easily blood flowing in from the first port circulates around the housing. If the latter is prioritized, the opening of the second port may not be located on an imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space. In this case, it is preferable to provide an inclined surface, inclined with respect to the axis of the second port when viewed from the first direction, between the opening of the second port and the imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space. This inclined surface guides air to the opening of the second port.

[0022] According to the present disclosure, it is possible to provide a diaphragm type pressure measurement chamber in which blood is less likely to stagnate in the internal space.

[0023] FIG. 1 is a perspective view showing the configuration of a diaphragm-type pressure measurement chamber according to embodiment 1. FIG. 2 is a plan view of the pressure measurement chamber. FIG. 3 is a rear view of the pressure measurement chamber. FIG. 4A is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line IV-A, and FIG. 4B is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line IV-B. FIG. 5A is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line VA, and FIG. 5B is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line V-B. FIG. 6 is a plan view of the first case as viewed from above and below. FIG. 7 is a schematic diagram showing an example and a comparative example. FIG. 8 is a diagram showing the results of a simulation of the shear rate at the wall surface for each of the configurations of Example 1, Comparative Example 1, and Comparative Example 2. FIG. 9A is a bar graph showing the area of ​​the region where the shear rate of the wall surface is less than 100 / sec for each configuration of Example 1, Comparative Example 1, and Comparative Example 2 based on the simulation results. FIG. 9B is a bar graph showing the area of ​​the region where the shear rate of the wall surface is less than 10 / sec. FIG. 10 is a plan view of the first case of a diaphragm-type pressure measurement chamber according to embodiment 2, as seen from the top and bottom. FIG. 11 is a cross-sectional view of the diaphragm-type pressure measurement chamber according to embodiment 2, cut along a plane perpendicular to the front-to-back direction. FIG. 12A is a diagram showing a plan view of a blood flow simulation for the diaphragm-type pressure measurement chamber according to embodiment 2, and FIG. 12B is a diagram showing the simulation from a side view. FIG. 13A is a plan view of a diaphragm-type pressure measurement chamber according to embodiment 3, FIG. 13B is a plan view of the first case, and FIG. 13C is a cross-sectional view taken along the arrows C-C in FIG. 13A.

[0024] (Embodiment 1) A diaphragm-type pressure measurement chamber (hereinafter simply referred to as a "pressure measurement chamber") according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the concepts of directions used in the following description are used for convenience of explanation and do not limit the orientation of each disclosed configuration to those directions. Furthermore, the pressure measurement chamber described below is merely one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the following embodiment, and additions, deletions, or modifications to the configuration are possible within the scope of the disclosure.

[0025] The pressure measurement chamber 1 according to the first embodiment constitutes, for example, a part of a blood circuit provided in a dialysis system and measures the pressure of a patient's blood flowing through the blood circuit. The blood circuit includes, for example, a blood removal line that directs the patient's blood outside the body, a filter connected to the blood removal line that transfers specific components from the patient's blood into a dialysate to purify the blood, and a blood return line that returns the purified blood to the patient. A blood pump is also provided midway along the blood removal line to circulate blood through the blood circuit.

[0026] The dialysis system includes a blood circuit and a pressure measurement device. The pressure measurement device includes multiple pressure sensors, each connected to a different point (pressure measurement point) in the blood circuit via a pressure monitor line. The pressure measurement chamber 1 according to the present disclosure is provided between the pressure monitor line and the pressure measurement point in the blood circuit.

[0027] The pressure measurement chamber 1 is provided midway along the line through which blood flows in the blood circuit so as to constitute a part of the line. In this case, blood flows through the interior (first chamber 13a described below) of the pressure measurement chamber 1. Note that the pressure measurement chamber 1 can also be provided so as to be connected to another line that branches off from the line through which blood flows in the blood circuit via a drip chamber or the like.

[0028] [Pressure Measurement Chamber] The configuration of the pressure measurement chamber 1 will be described in detail below. FIG. 1 is a perspective view showing the configuration of the pressure measurement chamber 1 according to the first embodiment. FIG. 2 is a plan view of the pressure measurement chamber 1, and FIG. 3 is a rear view of the pressure measurement chamber 1. Furthermore, FIG. 4A is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line IV-A, FIG. 4B is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line IV-B, FIG. 5A is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line VA (the same as line IV), and FIG. 5B is a cross-sectional view of the pressure measurement chamber of FIG. 2 taken along line V-B.

[0029] As shown in FIG. 1 , the pressure measurement chamber 1 has a housing 14, which is made of a first case 11 and a second case 12, both made of resin, joined together to form a chamber space 13 (see, e.g., FIG. 4A ). A flexible diaphragm 15 (see, e.g., FIG. 4B ) is provided within the housing 14. The chamber space 13 is divided by the diaphragm 15 into a first chamber (liquid chamber) 13a on the first case 11 side and a second chamber (air chamber) 13b on the second case 12 side. That is, the first chamber 13a and the second chamber 13b are both in contact with the diaphragm 15 and are separated from each other in an airtight and liquid-tight manner by the diaphragm 15. The first case 11 is formed with a first port (inlet port) P1 and a second port (outlet port) P2, and the second case 12 is formed with a third port (monitor port) P3.

[0030] The pressure measurement chamber 1 has a generally circular dome-like outer shape, and its orientation during use is not particularly limited. However, for ease of explanation, the directions related to the pressure measurement chamber 1 are defined as follows: the direction in which the second case 12 is located relative to the first case 11 is referred to as "upward," and the opposite direction is referred to as "downward." The direction in which the second port P2 is located relative to the first port P1 is referred to as "forward," and the opposite direction is referred to as "rearward." Furthermore, a direction intersecting both the up-down direction (first direction) and the front-to-back direction (second direction) is referred to as the "left-to-right direction" (third direction) relative to the forward direction. Therefore, the first direction corresponds to the direction in which the first chamber 13a, which is a liquid chamber, and the second chamber 13b, which is an air chamber, overlap.

[0031] 4A and 4B , the first case 11 includes a case body 20, to which a first port P1 and a second port P2 are connected. The first port P1 extends toward the chamber space 13 and has an axis A1 that defines the direction of inflow into the chamber space 13. The second port P2 extends toward the chamber space 13 and has an axis A2 that defines the direction of outflow from the chamber space 13. The case body 20 has an opening 21 that opens upward and an inner surface 22 that is recessed downward. The inner surface 22 and the lower surface of the diaphragm 15 form a first chamber 13a, which is a lower space (liquid chamber) within the chamber space 13. The chamber space 13 has a generally circular shape when viewed in a plan view along the vertical direction (first direction). In the embodiment, the shape of the chamber space 13 when viewed in a plan view along the vertical direction (first direction) is a perfect circle, but it may be another circular shape, such as an ellipse. Furthermore, the shape is not limited because any shape can improve the fluidity within the chamber compared to when a conventional port in which the axes of the inlet and outlet ports are the same is used. In the embodiment, the overall shape of the case is an oblate spheroid, but is not limited to this and may be a sphere, a spheroid, or another shape. In the following description, the center position of the chamber space 13 when viewed along the first direction is referred to as a center CP.

[0032] As shown in Fig. 4A, a first circumferential portion 23 is formed in the opening 21 of the case body 20, expanding in the radial direction from the upper end portion of the inner surface 22 and surrounding the opening 21. The first circumferential portion 23 has an inner wall 23a, a lower wall 23b, and an outer wall 23c, and a first circumferential groove 24 is formed surrounded by these three walls and opens upward. Therefore, the first circumferential groove 24 is provided around the opening 21 along the first circumferential portion 23. The outer wall 23c extends to a position higher than the inner wall 23a.

[0033] A first port P1, which is an inlet to the chamber space 13, is integrally formed at the rear of the case body 20. The first port P1 has a cylindrical shape, and its internal flow path is connected to the first chamber 13a within the case body 20. This first port P1 is a port through which blood flows from the blood circuit into the first chamber 13a. As shown in FIG. 4B , the inner diameter of the rear portion of the first port P1 is larger than the inner diameter of the front portion, and a step is formed at the boundary between the rear and front portions on the inner circumferential surface. A flexible tube T1 is inserted into the rear portion of the first port P1, and the end of the inserted tube T1 abuts against the step. When the end of the tube T1 abuts against the step, the inner circumferential surface of the tube T1 and the inner circumferential surface of the front portion of the first port P1 are approximately flush with each other. Furthermore, a first guide portion 25a is formed on the inner surface 22 of the case body 20, extending from the first port P1 and having a stepped portion relative to the inner surface 22. In the example shown in FIGS. 4A and 4B , the first guide portion 25a is formed as a groove recessed into the inner surface 22, and its depth decreases with increasing distance from the first port P1 along the extension direction. Note that the first port P1 is fixed to the tube T1 with a solvent or the like, but the first port P1 may also be configured as a connector to which the tube T1 or the like is connected. Furthermore, the first guide portion 25a is not limited to a groove configuration and may be configured as, for example, a rib having a stepped portion relative to the inner surface 22.

[0034] A second port P2, which is an outlet from the chamber space 13, is integrally formed in the front portion of the case body 20 and extends in a direction away from the first port P1. The second port P2 is tubular, and its internal flow path is connected to the first chamber 13a within the case body 20. This second port P2 is a port through which blood flows out from the first chamber 13a to the blood circuit. As shown in FIG. 5B , the inner diameter of the front portion of the second port P2 is larger than the inner diameter of the rear portion, and a step is formed at the boundary between the front and rear portions of the inner circumferential surface. A flexible tube T2 is inserted into the front portion of the second port P2, and the end of the inserted tube T2 abuts against the step. When the end of the tube T2 abuts against the step, the inner circumferential surface of the tube T2 and the inner circumferential surface of the rear portion of the second port P2 are substantially flush with each other. Additionally, a second guide portion 25b is formed on the inner surface 22 of the case body 20, extending from the second port P2 and having a stepped portion relative to the inner surface 22. In the example shown in FIGS. 5A and 5B , the second guide portion 25b is formed as a groove recessed into the inner surface 22, and its depth decreases with increasing distance from the second port P2 along the extension direction. Note that the second port P2 is fixed to the tube T2 with a solvent or the like, but the second port P2 may also be configured as a connector to which the tube T2 or the like is connected. Furthermore, the second guide portion 25b is not limited to a groove configuration and may be configured as, for example, a rib having a stepped portion relative to the inner surface 22.

[0035] The first port P1 and the second port P2 are provided at separate locations, one behind the other in front of the case body 20 of the first case 11, with the center (the center when viewed from the up-down direction) sandwiched between them. The first port P1 and the second port P2 are not arranged coaxially with each other. The arrangement of the first port P1 and the second port P2 will be described in more detail later. The first port P1 and the second port P2 have substantially the same cross-sectional shape and area of ​​the flow passage, and are positioned in the same up-down direction.

[0036] As shown in FIG. 3 , two plate-shaped legs 26a and 26b extend from the bottom of the case body 20. These legs 26a and 26b are located to the right and left of the center of the case body 20 (which in this embodiment coincides with the center CP of the chamber space 13) and are parallel to each other. Furthermore, the leg 26a is located on the farther side (right side) from the center CP on the outer bottom surface of the first guide portion 25a extending from the first port P1, while the leg 26b is located on the farther side (left side) from the center CP on the outer bottom surface of the second guide portion 25b extending from the second port P2. Furthermore, the leg 26a extends forward and rearward across the center CP in the front-to-rear direction, with its rear end positioned farther from the center CP than its front end. The leg 26b also extends forward and rearward across the center CP in the front-to-rear direction, with its front end positioned farther from the center CP than its rear end. The lower ends of the two legs 26a and 26b are located on the same plane perpendicular to the up-down direction.

[0037] 5A and 5B, the second case 12 includes a case body 30, and the third port P3 is connected to the case body 30. The case body 30 is generally dome-shaped and bulges upward, has an opening 31 that opens downward, and has an inner surface 32 that is recessed upward, and the inner surface 32 and the upper surface of the diaphragm 15 form a second chamber 13b, which is an upper space (air chamber) of the chamber space 13.

[0038] 5A , a second circumferential portion 33 is formed in the opening 31 of the case body 30, expanding in the radial direction from the lower end portion of the inner surface 32 and circumferentially surrounding the opening 31. The second circumferential portion 33 has an inner wall 33a, an upper wall 33b, and an outer wall 33c, and a second circumferential groove 34 is formed surrounded by these three walls and opens downward. Therefore, the second circumferential groove 34 is provided around the opening 31 along the second circumferential portion 33. The inner wall 33a and the outer wall 33c extend downward to approximately the same position in the up-down direction.

[0039] A third port P3 is integrally formed with the case body 30. The third port P3 protrudes from the upper portion of the case body 30. Its internal flow path is connected at its rear portion to the second chamber 13b at the upper end of the second chamber 13b, and its front portion is open forward so that a flexible tube T3 can be inserted into it from the front. The inner diameter of the front portion of the third port P3 is larger than that of the rear portion, and a step is formed at the boundary between the front and rear portions of the inner circumferential surface. When the tube T3 is inserted into the third port P3 until the end of the tube T3 abuts against the step of the third port P3, the inner circumferential surface of the tube T3 and the inner circumferential surface of the front portion of the third port P3 are substantially flush with each other. The third port P3 is fixed to the tube T3 with a solvent or the like, but the third port P3 may also be configured as a connector to which the tube T3 or the like is connected.

[0040] [Diaphragm] The diaphragm 15 is a dome-shaped membrane with appropriate flexibility, and deforms in the up-down direction (first direction) toward either the first chamber 13a or the second chamber 13b in response to the differential pressure between the first chamber 13a and the second chamber 13b (the difference in internal pressure). That is, the direction of deformation of the diaphragm 15 (up-down direction) due to changes in the differential pressure between the first chamber 13a and the second chamber 13b intersects with the direction of blood flow in the first chamber 13a (front-rear direction).

[0041] As shown in FIG. 4A , the diaphragm 15 includes a flexible membrane 40 having a dome-shaped membrane portion 41 and a flange portion 42 that extends outward (in the radial direction) from the outer peripheral edge of the membrane portion 41 to form an annular shape. The outer peripheral edge of the flange portion 42 is provided with an enlarged portion 43 that is larger in the up-down direction than the flange portion 42. The enlarged portion 43 is provided around the outer peripheral edge of the flange portion 42. The diaphragm 15 also includes a support frame 45 made of a material that is less flexible than the flexible membrane 40. The support frame 45 has a cross-sectional shape that covers the outer portion of the flange portion 42 of the flexible membrane 40 and the enlarged portion 43, and is annular as a whole, conforming to the enlarged portion 43.

[0042] The diaphragm 15 is supported by sandwiching the support frame 45 between the first circumferential portion 23 of the first case 11 and the second circumferential portion 33 of the second case 12 from above. That is, the lower part of the support frame 45 of the diaphragm 15 is fitted into the first circumferential groove 24 formed in the first circumferential portion 23 of the first case 11. In this state, the second case 12 is placed from above over the first case 11 and the diaphragm 15. At this time, the upper part of the support frame 45 of the diaphragm 15 is fitted into the second circumferential groove 34 formed in the second circumferential portion 33 of the second case 12.

[0043] This allows the diaphragm 15, which has a highly flexible flexible film 40, to be stably assembled to the housing 14. As described above, the pressure measurement chamber 1 according to the present disclosure includes two legs 26a, 26b. Therefore, the first case 11 can be stably placed, making it easy to assemble the first case 11, the second case 12, and the diaphragm 15.

[0044] 4A, etc., the pressure measurement chamber 1 according to the present disclosure is used for pressure measurement in a state in which the membrane portion 41 is convex upward and the first chamber 13a has a larger volume than the second chamber 13b. However, the pressure measurement chamber 1 can also be used for pressure measurement in a state in which the membrane portion 41 is convex downward and the second chamber 13b has a larger volume than the first chamber 13a.

[0045] [Detailed Configuration of First Case] ​​Figure 6 is a plan view of the first case 11 as viewed from the top-bottom direction (first direction). As shown in Figure 6, when the pressure measurement chamber 1 according to the present disclosure is viewed along the first direction, the axis A1 of the first port P1 intersects with the inner surface 22 of the housing 14, away from the center CP of the chamber space 13, so as to divide the chamber space 13 into a first region 131 and a second region 132 larger than the first region 131. The second port P2 is not connected to the first region 131 but is connected to the second region 132. In addition, if the opening in the housing 14 that communicates with the first port P1 is defined as the first opening P11 and the opening that communicates with the second port P2 is defined as the second opening P21, the second opening P21 is located on the opposite side of the center CP of the chamber space 13 from the direction approaching the first opening P11. In the example of FIG. 6, the first port P1 and the second port P2 are provided at a distance from each other at the rear and front of the case body 20 of the first case 11, with the center CP sandwiched between them.

[0046] The first opening P11 is the portion surrounded by a dashed line in FIGS. 4B and 6 . Specifically, the first opening P11 is the portion closest to the first port P1 among the intersections between the flow path from the first port P1 to the first chamber 13a and the inner surface 22 of the first case 11. The position of the first opening P11 is more accurately represented by the center of the first opening. Similarly, the second opening P21 is the portion surrounded by a dashed line in FIGS. 5B and 6 . Specifically, the second opening P21 is the portion closest to the second port P2 among the intersections between the flow path from the second port P2 to the first chamber 13a and the inner surface 22 of the first case 11. The position of the second opening P21 is more accurately represented by the center of the second opening.

[0047] 6, the opening direction of the first port P1 into the first chamber 13a is forward along the axis A1 of the first port P1. In contrast, the opening direction of the second port P1 into the first chamber 13a is rearward along the axis A2 of the second port P2. Therefore, the opening direction (forward) of the first port P1 into the first chamber 13a and the opening direction (rearward) of the second port P2 into the first chamber 13a are opposite to each other.

[0048] Furthermore, the internal space of the first port P1 is directly connected to the first chamber 13a, and no structures such as walls or protrusions that would change the flow of blood from the first port P1 to the first chamber 13a along the axis A1 are provided between them. Therefore, when the first port P1 is viewed along its axis A1, the first chamber 13a connected to the internal space of the first port P1 can be seen. Similarly, the internal space of the second port P2 is directly connected to the first chamber 13a, and no structures such as walls or protrusions that would change the flow of blood from the first chamber 13a to the second port P2 along the axis A2 are provided between them. Therefore, when the second port P2 is viewed along its axis A2, the first chamber 13a connected to the internal space of the second port P2 can be seen.

[0049] 6, in the pressure measurement chamber 1 according to the first embodiment, the first port P1 and the second port P2 may be arranged such that the axis A1 of the first port P1 and the axis A2 of the second port P2 are spaced apart from each other and parallel to each other when viewed in the first direction. Alternatively, the first port P1 and the second port P2 of the pressure measurement chamber 1 may be configured such that the axis A1 of the first port P1 and the axis A2 of the second port P1 are inclined to each other and do not intersect within the chamber space 13 but intersect outside the chamber space 13.

[0050] As described above, when viewed along the first direction in which the first chamber 13a, which is a liquid chamber, and the second chamber 13b, which is an air chamber, overlap, the pressure measurement chamber 1 according to this embodiment has the axis A1 of the first port P1 intersecting the inner surface 22 of the housing 14 at a position offset from the center CP so as to divide the chamber space 13 into a first region 131 and a second region 132 larger than the first region 131, and the second port P2 is connected to the second region 132. This arrangement prevents blood from stagnating within the liquid chamber. Specifically, because the inner surface 22 of the housing 14 is located on the axis A1 of the first port P1, which is the center of the blood flow formed by the first port P1, the blood tends to spread in a direction perpendicular to the axis A1 of the first port P1. Furthermore, because the second port P2 is connected to the second region 132, blood flowing in from the first port P1 tends to be drawn toward the second region 132. Therefore, when viewed from the first direction, the blood flowing in from the first port P1 tends to spread in a direction perpendicular to the axis A1 of the first port P1, and compared to conventional chambers in which the second port P2 is positioned on the axis A1 of the first port P1, the area over which the blood in the liquid chamber is stirred is wider, thereby preventing blood from stagnating in the liquid chamber.

[0051] Furthermore, in the pressure measurement chamber 1 according to this embodiment, the bottom surface of the tip portion of the first guide portion 25a in the first case 11 may extend in the first direction toward the diaphragm 15 (i.e., upward) as it moves from the base end side to the tip end side. Specifically, as shown in Fig. 6, the first guide portion 25a has a proximal portion 25a1 close to the first port P1 and a distal portion 25a2 away from the first port P1. Of these, the bottommost portion of the proximal portion 25a1 has a constant vertical position throughout the entire front-to-rear direction, while the bottommost portion of the distal portion 25a2 is inclined upward as it moves forward (see also Fig. 4B).

[0052] As described above, the pressure measurement chamber 1 according to this embodiment may be configured so that the axis A1 of the first port P1 and the axis A2 of the second port P2 are spaced apart and parallel to each other, or so that the axis A1 of the first port P1 and the axis A2 of the second port P2 are inclined to each other and intersect outside the chamber space 13. This makes it possible to suppress the amount of blood that flows in from the first port P1 and is drawn into the second port P2 before it collides with the inner surface 22 of the housing 14 opposite the first port P1. This suppresses a strong flow that flows along the straight line connecting the first port P1 and the second port P2, and strengthens a flow that bypasses the straight line along the inner surface 22 of the housing 14.

[0053] In the present disclosure, the bottom surface of the distal end portion of the second guide portion 25b also extends upward from the base end side to the distal end side. Specifically, the second guide portion 25b similarly has a proximal portion 25b1 close to the second port P2 and a distal portion 25b2 far from the second port P2. Of these, the bottommost portion of the proximal portion 25b1 is at a constant vertical position throughout the entire fore-aft direction, while the bottommost portion of the distal portion 25b2 slopes upward toward the rear (see also FIG. 5B ).

[0054] The first guide portion 25a and the second guide portion 25b described above are optional components for the pressure measurement chamber 1 according to this embodiment and may or may not be included. Furthermore, both the first guide portion 25a and the second guide portion 25b may be employed, or only one of them may be employed. Furthermore, the second opening P21 of the second port P2 is preferably formed at a position where it intersects with an imaginary line that is parallel to the axis A1 of the first port P1 and passes through the center CP of the chamber space 13, or at a position farther from the first port P1 than the imaginary line, when viewed from the first direction.

[0055] The first port P1 and the second port P2 shown in FIG. 6 may be arranged asymmetrically as follows. That is, a virtual line V1 is defined as a virtual line parallel to the axis A2 of the second port P2 and passing through the center CP of the chamber space 13. A virtual line V2 is defined as a virtual line parallel to the axis A2 of the second port P2 and intersects the first opening P11 of the first port P1 at its center. A virtual line V3 is defined as a virtual line parallel to the axis A2 of the second port P2 and intersects the second opening P21 of the second port P2 at its center. The minimum distance between the virtual line V1 and the virtual line V2 is defined as L1, and the minimum distance between the virtual line V1 and the virtual line V3 is defined as L2. In this case, the pressure measurement chamber 1 may be configured such that the distance L1 is greater than the distance L2 between the first port P1 and the second port P2. The axis A2 and the virtual line V3 of the second port P2 described above are substantially identical. Furthermore, when the first port P1 and the second port P2 are parallel to each other, the axis A1 of the first port P1 and the imaginary line V2 are substantially the same.

[0056] As a result, the first opening P11 of the first port P1 is positioned farther away from the center CP of the chamber space 13, making it easier for blood flowing in from the first port P1 to flow along the inner wall of the housing 14. On the other hand, the second port P2, which is on the outlet side, is positioned so that its axis A2 is closer to the center CP of the chamber space 13, improving the ability to remove air from the chamber space 13.

[0057] 7 is a schematic diagram showing an example and a comparative example with respect to the arrangement of the first port P1 and the second port P2. Example 1 has the same configuration as the pressure measurement chamber 1 shown in FIGS. 1 to 6. That is, in the pressure measurement chamber 1 according to Example 1, the axis A1 of the first port P1 and the axis A2 of the second port P2 are spaced apart from each other and parallel to each other. In the pressure measurement chamber 1 according to Example 2, the axis A1 of the first port P1 and the axis A2 of the second port P2 are inclined to each other and do not intersect within the chamber space 13, but intersect outside the chamber space 13.

[0058] On the other hand, Comparative Example 1 is configured such that the axis A1 of the first port P1 and the axis A2 of the second port P2 intersect within the chamber space 13. Note that FIG. 7 shows an example in which the axis A1 of the first port P1 and the axis A2 of the second port P2 intersect at an angle of 135 degrees. Comparative Example 2 is configured such that the axis A1 of the first port P1 and the axis A2 of the second port P2 are positioned coaxially. Note that FIG. 7 for Comparative Example 2 shows an example in which the axis A1 of the first port P1 and the axis A1 of the second port P2 are coaxial and pass through the center CP of the chamber space 13.

[0059] 8 is a diagram showing the results of a simulation of the shear rate at the wall surface for each of the configurations of Example 1, Comparative Example 1, and Comparative Example 2. Here, the simulation conditions were a flow rate of the fluid flowing into the chamber space 13 from the first port P1 of 300 mL / min, and an outlet pressure at the second port P2 of 0 Pa. In FIG. 8, the gray density increases as the shear rate decreases.

[0060] 9A and 9B are graphs that quantify the simulation results of Fig. 8, and "A" on the horizontal axis of each graph corresponds to Example 1, "B" to Comparative Example 1, and "C" to Comparative Example 2. Fig. 9A is a bar graph showing the area of ​​the region where the shear rate on the wall surface is less than 100 / sec from the simulation results, and Fig. 9B is a bar graph showing the area of ​​the region where the shear rate on the wall surface is less than 10 / sec.

[0061] As can be seen from Figure 8, the configuration of Comparative Example 1 has more dark-colored portions than the pressure measurement chamber 1 of Example 1. Also, the configuration of Comparative Example 2 has significantly more dark-colored portions than the pressure measurement chamber 1 of Example 1. According to Figure 9A, the region where the shear rate is less than 100 / sec is about 1.5 times longer in the configuration of Comparative Example 1 than in the configuration of Example 1, and about 8.5 times longer in the configuration of Comparative Example 2 than in the configuration of Example 1. Also, according to Figure 9B, the region where the shear rate is extremely low, less than 10 / sec, is about twice longer in the configuration of Comparative Example 1 than in the configuration of Example 1, and about 10 times longer in the configuration of Comparative Example 2 than in the configuration of Example 1.

[0062] As can be seen from the above simulation results, the pressure measurement chamber 1 according to Example 1, which is equipped with the configuration relating to the arrangement of the first port P1 and the second port P2 described in this embodiment, has a higher shear rate on the wall surface than the pressure measurement chambers according to Comparative Examples 1 and 2, which are not equipped with this configuration. Therefore, with the configuration according to Example 1, blood is less likely to stagnate near the wall surface, and the occurrence of thrombi can be effectively suppressed.

[0063] 10 is a plan view of a first case 11A of a pressure measurement chamber 1A according to a second embodiment, and FIG. 11 is a cross-sectional view of the pressure measurement chamber 1A according to the second embodiment, taken along a plane perpendicular to the front-to-rear direction, looking forward toward the second port. In the pressure measurement chamber 1A according to the second embodiment, the first port P1 and the second port P2 are arranged asymmetrically with respect to the center CP of the chamber space 13. In addition, the pressure measurement chamber 1A has a guide portion 53 having a stepped portion provided on the inner surface 22 of the first case 11A.

[0064] 10 includes a case body 20, a first port P1, and a second port P2, similar to the first case 11 of embodiment 1. The case body 20 is circular in plan view, and the chamber space 13 (first chamber 13a) formed between the case body 20 and the diaphragm 15 is also circular in plan view. Therefore, the center of the housing 14 substantially coincides with the center CP of the chamber space 13.

[0065] The pressure measurement chamber 1 of embodiment 1 includes a second case 12 having a configuration similar to that of the pressure measurement chamber 1A of embodiment 2. Therefore, the following description will mainly focus on the first case 11A of the pressure measurement chamber 1A, which has a different configuration from that of the pressure measurement chamber 1.

[0066] [Regarding the Ports] When the pressure measurement chamber 1A is viewed in the first direction, the axis A1 of the first port P1 intersects with the inner surface 22 of the first case 11A, away from the center CP of the chamber space 13, so as to divide the chamber space 13 into a first region 131 and a second region 132 that is larger than the first region 131. The second port P2 is not connected to the first region 131 but is connected to the second region 132. In the first case 11A, if the opening communicating with the first port P1 is defined as the first opening P11 and the opening communicating with the second port P2 is defined as the second opening P21, the second opening P21 is located on the opposite side of the center CP of the chamber space 13 from the direction approaching the first opening P11. In the example of FIG. 10 , the first port P1 and the second port P2 are provided at separate locations on the rear and front sides of the center CP in the case body 20 of the first case 11A.

[0067] As shown in FIG. 10 , the pressure measurement chamber 1A may adopt the following asymmetrical arrangement configuration for the arrangement of the first port P1 and the second port P2. Specifically, a virtual line V1 is defined as a virtual line parallel to the axis A2 of the second port P2 and passing through the center CP of the chamber space 13. A virtual line V2 is defined as a virtual line parallel to the axis A2 of the second port P2 and intersects the first opening P11 of the first port P1 at its center. A virtual line V3 is defined as a virtual line parallel to the axis A2 of the second port P2 and intersects the second opening P21 of the second port P2 at its center. The minimum distance connecting the virtual lines V1 and V2 is defined as L1, and the minimum distance connecting the virtual lines V1 and V3 is defined as L2. In this case, the pressure measurement chamber 1 may be configured such that the distance L1 is greater than the distance L2 between the first port P1 and the second port P2. The axis A2 and the virtual line V3 of the second port P2 described above are substantially identical. Furthermore, when the first port P1 and the second port P2 are parallel to each other, the axis A1 of the first port P1 and the imaginary line V2 are substantially the same.

[0068] As a result, the first opening P11 of the first port P1 is positioned farther away from the center CP of the chamber space 13, making it easier for blood flowing in from the first port P1 to flow along the inner wall of the housing 14. On the other hand, the second port P2, which is on the outlet side, is positioned so that its axis A2 is closer to the center CP of the chamber space 13, improving air bleedability from the chamber space 13. Note that if improving air bleedability is more important, the second opening P21 may be positioned so that it intersects with an imaginary line V5 that is parallel to the axis A1 of the first port P1 and passes through the center CP of the chamber space 13. For example, the imaginary line V5 and the second opening P21 may intersect, and the center of the second opening P21 may be positioned closer to the first port P1 than the imaginary line V5. In the configuration of Figure 10, in order to emphasize the circulatory properties of the flow of blood flowing in from the first port P1, the second opening P21 does not intersect with the imaginary line V5, but is positioned slightly offset from the imaginary line V5 in a direction away from the first port P1 (to the left).

[0069] 10 , the portion 51R of the inner circumferential surface 51 forming the internal flow path 51S of the first port P1, which is furthest from the center CP to one side in the left-right direction (the right side), and the portion 22R of the inner surface 22 of the case body 20, which is furthest from the center CP to the right side, are positioned approximately in the left-right direction. For example, the portion 51R of the inner circumferential surface 51 of the first port P1 and the portion 22R of the inner surface 22 of the case body 20 are flush with each other. In contrast, the portion 52L of the inner circumferential surface 52 forming the internal flow path 52S of the second port P2, which is furthest from the center CP to the other side in the left-right direction (the left side), is positioned closer to the center CP than the portion 22L of the inner surface 22 of the case body 20, which is furthest from the center CP to the left side.

[0070] Because the pressure measurement chamber 1A has the first port P1 and the second port P2 configured as described above, blood flowing in from the first port P1 flows along the inner wall of the housing 14 and is easily stirred, and air is easily removed from the second port P2.

[0071] 10 , in the pressure measurement chamber 1A according to the second embodiment, the first port P1 and the second port P2 may also be arranged such that the axis A1 of the first port P1 and the axis A2 of the second port P2 are spaced apart from each other and parallel to each other when viewed in the first direction. Alternatively, the first port P1 and the second port P2 of the pressure measurement chamber 1A may be configured such that the axis A1 of the first port P1 and the axis A2 of the second port P1 are inclined to each other and do not intersect within the chamber space 13 but intersect outside the chamber space 13.

[0072] [Regarding the Guide Portion] As shown in Fig. 11 , a first guide portion 53 having a stepped portion is provided on the inner surface 22 of the case body 20. The first guide portion 53 is configured to guide blood flowing in from the first port P1 and has an upper guide portion 54 extending toward the diaphragm 15 in the first direction. The upper guide portion 54 is located above the lower end of the first opening P11 of the first port P1 and, when viewed in the first direction as shown in Fig. 10 , is formed between the axis A1 of the first port P1 and an imaginary line V4 that is parallel to the axis A1 and passes through the second opening P21 of the second port P2. As shown in Fig. 10 , for example, the imaginary line V4 is parallel to the axis A1 of the first port P1 and passes through the right end of the second opening P21 (the end closer to the first port P1 as viewed in the first direction).

[0073] The upper guide portion 54 may be configured to extend upward and intersect with the axis A1 of the first port P1. Alternatively, as shown in Fig. 11, the upper guide portion 54 may be configured to extend upward from the lower end of the first opening P11 of the first port P1 beyond the axis A1 of the first port P1. In Fig. 11, the upper guide portion 54 extends upward beyond the second opening P21 of the second port P2, making it easier for blood to flow upward than in the second port. Although the first port P1 and the second port P2 are parallel to each other in the example of Fig. 10, they do not have to be parallel to each other.

[0074] This upper guide portion 54 makes it easier for the blood flowing in from the first port P1 and flowing along the inner surface 22 of the housing 14 to flow upward, thereby reducing blood stagnation in the area near the edge of the diaphragm 15.

[0075] 10 , the first guide portion 53 may have a circumferential guide portion 55 that is located between the axis A1 of the first port P1 and an imaginary line V4 that is parallel to the axis A1 and passes through the second opening P21 of the second port P2, and that extends from the axis A1 of the first port P1 in a direction toward the imaginary line V4. Note that the circumferential guide portion 55 may extend further beyond the imaginary line V4 so as to approach the axis A2.

[0076] The circumferential guide portion 55 may be provided on the first guide portion 53 together with the above-described upper guide portion 54, or without the upper guide portion 54. The circumferential guide portion 55 is preferably formed so as to be connected to the axis A1 of the first port P1. That is, the circumferential guide portion 55 can be formed so as to intersect with the axis A1.

[0077] Such a circumferential guide portion 55 can direct blood flowing from the first port P1 toward the second port P2, which is located off the axis A1 of the first port P1. This prevents blood from dispersing and flowing in the direction opposite the second port P2, making it easier for a strong flow to pass over the second port P2 and circulate around the housing 14, and also prevents blood from accumulating within the first guide portion 53. In FIG. 11 , the first guide portion 53 includes the circumferential guide portion 55 and the upper guide portion 54 and extends obliquely upward, but the circumferential guide portion 55 and the upper guide portion 54 may be formed separately and extend in a stepped manner.

[0078] 10 , the first guide portion 53 may have an axial guide portion 56 that extends from the first port P1 in a direction along the axis A1 of the first port P1 when viewed from the first direction. This makes it possible to converge the flow direction of the blood that has flowed from the first port P1 into the first chamber 13a of the chamber space 13 to a certain extent in the same direction before it collides with the inner surface 22 of the housing 14, thereby increasing the momentum of the blood in the direction of collision with the inner surface 22 of the housing 14.

[0079] 10 and 11 , the first guide portion 53 may include all of the above-described upper guide portion 54, circumferential guide portion 55, and axial guide portion 56, but is not limited to this. That is, the first guide portion 53 may be configured to include any one or two of these guide portions 54, 55, and 56. For example, the guide portion 54 may be configured to include only the axial guide portion 56.

[0080] Furthermore, one of these guide portions 54, 55, 56 may also serve as one or two of the others. For example, as shown in Fig. 11 , the upper guide portion 54 may also serve as the circumferential guide portion 55. In this case, the upper guide portion 54 may extend in the first direction toward the diaphragm 15, and may also extend from the axis A1 toward the imaginary line V4, similar to the circumferential guide portion 55.

[0081] As shown in FIGS. 10 and 11 , one or more of the guide portions 54, 55, and 56 may be formed as grooves recessed from the inner surface 22. Alternatively, they may be formed as ribs protruding from the inner surface 22. The first guide portion 53 may extend from the first opening P11 of the first port P1 to the second opening P21 of the second port P2. In this case, the first guide portion 53 functions as a space-forming portion that defines a flow path from the first port P1 to the second port P2. Therefore, even if the diaphragm 15 bends downward to a state in which it contacts the inner surface 22, the flow path from the first port P1 to the second port P2 is not blocked. In the pressure measurement chamber 1A, the space-forming portion may be provided separately from the first guide portion 53, or may not be provided at all. When the space-forming portion is provided separately from the first guide portion 53, for example, a groove may be provided separately from the first guide portion 53, and the space-forming portion may be formed by this groove.

[0082] As shown in Fig. 10, a second guide portion 60 is provided on the inner surface 22 of the case body 20. This second guide portion 60 is a groove that extends the internal flow path 52S of the second port P2 into the chamber space 13. When viewed in the front-to-rear direction as shown in Fig. 11, the inner bottom surface of the second port P2 and the inner bottom surface of the second guide portion 60 are flush with each other. When viewed in the first direction, the second guide portion 60 has a tapered shape in which the left-to-right width dimension decreases with increasing distance from the second port P2.

[0083] Additionally, a notch 62 that opens upward is formed on the inner surface 22 of the case body 20 above the second port P2. When viewed in the front-to-rear direction as shown in FIG. 11 , the notch 62 forms a tapered sidewall that increases in width toward the top. When viewed in a plan view along the first direction, the tapered sidewall has a tapered surface 61 that widens in the direction away from the axis A2 of the second port P2 (left-right direction) as it approaches the top. As shown in FIGS. 10 and 11 , this tapered surface 61 is a surface (surfaces 61a and 61b) that connects the inner surface 22 of the case body 20 and the second guide portion 60, or a surface (surface 61c) that connects the inner surface 22 and the inner circumferential surface 52 of the second port P2. 10, the tapered surface 61 has a first tapered surface 61a extending leftward from the left end of the second guide portion 60 in a plan view, and a second tapered surface 61b extending rightward from the right end of the second guide portion 60 (see also FIG. 11). In addition, as shown in FIG. 11, the tapered surface 61 has a third tapered surface 61c extending rearward from the inner circumferential surface 52 of the second port P2 above the second guide portion 60.

[0084] The first tapered surface 61a extends upward from the left end of the second guide portion 60 toward the left, with its upper end located at the opening 21 of the case body 20. The second tapered surface 61b extends upward from the right end of the second guide portion 60 toward the right, with its upper end located at the opening 21 of the case body 20. Therefore, the left-right separation between the first tapered surface 61a and the second tapered surface 61b increases upward. This first tapered surface 61a facilitates blood flowing along the inner surface 22 of the housing 14 to pass the second opening P21 of the second port P2 and flow away from the first port P1, as viewed from the first direction, thereby reducing a significant loss of momentum of the flow circulating around the housing 14. Furthermore, the second tapered surface 61b reduces blood stagnation where blood flows into the cutout portion 62.

[0085] The third tapered surface 61c extends upward toward the rear from the rear end (the end closer to the chamber space 13) of the inner circumferential surface 52 of the second port P2, and its upper end is located at the opening 21 of the case body 20. Therefore, the vertical position of the third tapered surface 61c becomes higher toward the rear, which reduces the possibility of blood stagnation behind the cutout portion 62.

[0086] 10, the pressure measurement chamber 1A may be configured so that an imaginary line V1 that is parallel to the axis A2 of the second port P2 and passes through the center CP of the chamber space 13 intersects with the second tapered surface 61b. Alternatively, the imaginary line V1 may be configured so as to intersect with the second guide portion 60. This improves the ability to remove air from the chamber space 13.

[0087] The axial guide portion 56 of the first guide part 53 extending from the first port P1 is a groove that extends the internal flow path 51S of the first port P1 into the chamber space 13. Therefore, when viewed in the front-rear direction, the internal flow path 51S of the first port P1 and the space 56S formed by the axial guide portion 56 have the same contour shape, mainly at the bottom. The left-right width dimensions of the axial guide portion 56 in a plan view are substantially the same at any position in the front-rear direction (see FIG. 10 ).

[0088] In this embodiment, the first guide portion 53 has a rear portion near the first port P1 that forms an axial guide portion 56, and a front portion near the second port P2 that forms an upper guide portion 54 and a circumferential guide portion 55. The first guide portion 53 is formed to communicate between the first port P1 and the second port P2. When viewed from above, the front portion of the first guide portion 53 gradually decreases in width and depth toward the front. Furthermore, as shown in FIG. 11 , the front portion of the first guide portion 53 slopes upward toward the second port P2, and a front end portion 53 f connects to the second port P2 via a second tapered surface 61 b ​​near the top end of the first case 11 (i.e., near the opening 21).

[0089] 10, the first guide portion 53 (particularly the circumferential guide portion 55) is curved to follow the shape of the chamber space 13. Therefore, blood flowing in from the first port P1 can be efficiently circulated within the chamber space 13. Furthermore, the first guide portion 53 (particularly the upper guide portion 54) is directed upward as it moves away from the first port P1, as shown in FIG. 11. Therefore, blood flowing in from the first port P1 can be guided from below to above within the first chamber 13a, forming a three-dimensional blood flow.

[0090] In this way, the first guide part 53 is curved along the shape of the chamber space 13 and extends from below to above. The results of a simulation of blood flow in the pressure measurement chamber 1A including such a first guide part 53 are shown in Figures 12A and 12B. Figure 12A is a diagram showing the results of a simulation of blood flow in the pressure measurement chamber 1A according to embodiment 2 in a plan view, and Figure 12B is a diagram showing the results of the simulation in a side view.

[0091] 12A shows that the blood flowing in from the first port P1 circulates horizontally, with the vertical axis as its axis. Also, FIG. 12B shows that the blood flowing in from the first port P1 also circulates vertically, with the horizontal axis as its axis. Thus, in the pressure measurement chamber 1A, the blood circulates three-dimensionally in both the horizontal and vertical directions. Therefore, the blood in the first chamber 13a can be efficiently agitated, and blood stagnation can be prevented.

[0092] The first guide portion 53 is not limited to the groove shape described above. For example, instead of a groove recessed from the inner surface 22, it may be configured by providing strip-like ribs protruding from the inner surface 22. However, if the first guide portion 53 is configured by a groove recessed from the inner surface 22, the blood flow is more easily concentrated and is less likely to interfere with the blood flow circulating within the chamber space 13, which is preferable.

[0093] Furthermore, the first guide portion 53, the second guide portion 60, and some or all of the tapered surface 61 described in the second embodiment can also be applied to the pressure measurement chamber 1 according to the first embodiment.

[0094] (Embodiment 3) The first guide portion 53 including the upper guide portion 54, the circumferential guide portion 55, and the axial guide portion 56 described in Embodiment 2 can also be applied to a pressure measurement chamber in which the first port P1 and the second port P2 are arranged differently from those in Embodiment 2. Figure 13 is a drawing showing a pressure measurement chamber 1B for explaining this, where Figure 13A is a plan view of the pressure measurement chamber 1B as seen from a first direction, Figure 13B is a plan view of a first case 11B provided in the pressure measurement chamber 1B, and Figure 13C is a cross-sectional view taken along the arrows CC in Figure 13A.

[0095] 13A, the pressure measurement chamber 1B has a first port P1 and a second port P2 extending in the same direction relative to the case body 20. That is, as shown in FIG. 13B, the first case 11B is configured so that the first port P1, the first chamber 13a forming the liquid chamber, and the second port P2 are arranged in that order in a U-shape. In this first case 11B, a first guide portion 53 is formed to guide blood from the first port P1 to the chamber space 13.

[0096] The first guide portion 53 included in the pressure measurement chamber 1B has the same configuration as the first guide portion 53 described in embodiment 2. However, the first guide portion 53 may be configured to include only one or two of the upper guide portion 54, the circumferential guide portion 55, and the axial guide portion 56.

[0097] The pressure measurement chamber 1B also includes a second guide portion 63 that guides blood in the chamber space 13 to the second port P2. As shown in Figures 13B and 13C, the second guide portion 63 has a different configuration from the second guide portion 60 described in the second embodiment, and is configured symmetrically to the first guide portion 53. The second guide portion 63 includes an upper guide portion 64, a circumferential guide portion 65, and an axial guide portion 56. Of these, the upper guide portion 64 has the same configuration as the upper guide portion 54, the circumferential guide portion 65 has the same configuration as the circumferential guide portion 55, and the axial guide portion 66 has the same configuration as the axial guide portion 56.

[0098] However, in the pressure measurement chamber 1B, the configuration of the second guide portion 63 is not limited to this. For example, in the example of FIG. 13B , the first guide portion 53 and the second guide portion 63 are symmetrically structured and arranged with respect to the axial direction of the third port P3. However, this is not limiting, and the structure and / or arrangement of the first guide portion 53 and the second guide portion 63 may be asymmetric with respect to the axial direction of the third port P3. In the third embodiment, taking into account air release performance, it is assumed that the first port P1 and the second port P2 are installed facing upward in the direction of gravity during use. In this case, however, there is a possibility that the tube connected to the first port P1 may kink. For this reason, it is considered to provide the first port P1 with a function to prevent kinking.

[0099] Although the pressure measurement chamber 1B described in this embodiment is configured to include both the first guide portion 53 and the second guide portion 63, a chamber configured to include only the first guide portion 53 may also be employed, which includes an upper guide portion, a circumferential guide portion, and an axial guide portion. Furthermore, pressure measurement chambers to which any one or more of the upper guide portion, the circumferential guide portion, and the axial guide portion can be applied are not limited to the configurations of Embodiments 1 to 3. For example, the present invention can also be applied to a chamber configured such that the axial centers of the first port and the second port intersect within the chamber space, as shown as Comparative Example 1 in FIG. 8 .

[0100] (Regarding Other Configurations) When viewed in the up-down direction (first direction), each of the pressure measurement chambers 1, 1A, and 1B may be configured so that the axis A1 of the first port P1 and the axis A2 of the second port P2 are parallel to each other and are positioned on either side of the center CP of the chamber space 13. This prevents the opening of the second port P2 from being on an extension of the opening direction of the first port P1 into the chamber space 13. This prevents blood flowing in from the first port P1 from directly entering the second port P2. Furthermore, by making the first port P1 and the second port P2 parallel to each other, the first case 11 can be easily released from a mold when molded from resin.

[0101] Furthermore, the pressure measurement chambers 1, 1A, and 1B may be configured such that, when viewed in the vertical direction (first direction), the axis A1 of the first port P1, the axis A2 of the second port P2, and the axis A3 of the third port P3 are spaced apart from each other and parallel to each other. Specifically, in the example of FIG. 2, the axis A3 is located between the axes A1 and A2. This makes it difficult for the tubes T1 to T3 connected to the three ports P1 to P3 to overlap each other when viewed from the vertical direction, making it easy to visually identify each tube T1 to T3. Therefore, for example, the presence or absence of air bubbles in the tubes T1 and T2 can be easily confirmed without being obstructed by the tube T3.

[0102] Additionally, the first case 11, 11A, 11B may be provided with an additional port for supplying a replacement fluid other than blood (e.g., heparin) to the first chamber 13a. The pressure measurement chambers 1, 1A, 1B according to the present disclosure suitably agitate the blood within the first chamber 13a, so that the replacement fluid supplied from the additional port is also agitated along with the blood and tends to be uniformly mixed with the blood within the first chamber 13a. Therefore, the concentration of the replacement fluid in the blood flowing out of the second port P2 can be made uniform.

[0103] In addition, in a blood circuit for dialysis, a blood flow sensing pillow is used to monitor the flow rate of blood withdrawn from a patient. The pillow is installed midway through the blood circuit and has a chamber made of a flexible material that expands and contracts depending on the blood flow rate. During use, the flow rate can be monitored by directly observing the chamber's expansion and contraction state. Furthermore, the pressure measurement chamber 1, 1A, or 1B according to the present disclosure can also be suitably used as this blood flow sensing pillow by omitting the upper second case 12 and connecting the peripheral edge of the diaphragm 15 to the peripheral edge of the first case 11, 11A, or 11B.

[0104] The present disclosure can be suitably applied to a diaphragm-type pressure measurement chamber for measuring the pressure of blood flowing through a blood circuit.

[0105] REFERENCE SIGNS LIST 1 Pressure measurement chamber 1A Pressure measurement chamber 1B Pressure measurement chamber 11 First case 12 Second case 13 Chamber space 13a First chamber (liquid chamber) 13b Second chamber (air chamber) 14 Housing 15 Diaphragm 40 Flexible membrane 55 Communication groove (space forming portion) P1 First port P2 Second port P3 Third port

Claims

1. A diaphragm-type pressure measurement chamber comprising: a housing having a chamber space therein; a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber; a first port connected to the housing and allowing blood to flow into the liquid chamber; and a second port extending in a direction away from the first port and connected to the housing and allowing blood to flow out of the liquid chamber; when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port is offset from the center of the chamber space and intersects with the inner surface of the housing so as to divide the chamber space into a first area and a second area larger than the first area; and the second port is connected to the second area; and the axis of the first port and the axis of the second port are configured so as to be spaced apart from each other and parallel to each other, or so as to be inclined from each other and intersect outside the chamber space.

2. A blood supply device comprising: a housing having a chamber space therein; a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber; a first port connected to the housing to allow blood to flow into the liquid chamber; and a second port connected to the housing to allow blood to flow out of the liquid chamber; when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port deviates from the center of the chamber space and intersects with the inner surface of the housing so as to divide the chamber space into a first area and a second area larger than the first area; the second port is connected to the second area; a guide section having a stepped section is formed on the inner surface of the housing, and the guide section has an upper guide section that extends in a direction approaching the diaphragm in the first direction; the upper guide section is located above the lower end of the opening of the first port and, when viewed along the first direction, is formed between the axis of the first port and an imaginary line that is parallel to the axis of the first port and passes through the opening of the second port. Diaphragm type pressure measurement chamber.

3. A diaphragm-type pressure measurement chamber comprising: a housing having a chamber space therein; a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber; a first port connected to the housing to allow blood to flow into the liquid chamber; and a second port connected to the housing to allow blood to flow out of the liquid chamber; when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port deviates from the center of the chamber space and intersects with the inner surface of the housing so as to divide the chamber space into a first area and a second area larger than the first area; the second port is connected to the second area; a guide part with a stepped portion is formed on the inner surface of the housing, and the guide part has a circumferential guide part that is located between the axis of the first port and an imaginary line that is parallel to the axis of the first port and passes through the opening of the second port, and that extends from the axis of the first port in a direction approaching the imaginary line.

4. A diaphragm-type pressure measurement chamber comprising: a housing having a chamber space therein; a flexible diaphragm dividing the chamber space into a liquid chamber and an air chamber; a first port connected to the housing to allow blood to flow into the liquid chamber; and a second port connected to the housing to allow blood to flow out of the liquid chamber; when viewed along a first direction in which the liquid chamber and the air chamber overlap, the axis of the first port deviates from the center of the chamber space and intersects with the inner surface of the housing so as to divide the chamber space into a first area and a second area larger than the first area; the second port is connected to the second area; and a guide part with a stepped part is formed on the inner surface of the housing, and the guide part has an axial guide part extending from the first port in the axial direction of the first port when viewed from the first direction.

5. A diaphragm type pressure measurement chamber as claimed in any one of claims 1 to 4, wherein the minimum distance connecting an imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space with an imaginary line that is parallel to the axis of the second port and intersects with the center of the opening of the second port is shorter than the minimum distance connecting an imaginary line that is parallel to the axis of the second port and passes through the center of the chamber space with an imaginary line that is parallel to the axis of the second port and intersects with the center of the opening of the first port.

6. A diaphragm type pressure measurement chamber as set forth in claim 1, wherein a guide portion having a stepped portion is formed on the inner surface of the housing, and the guide portion has an upper guide portion that extends toward the diaphragm in the first direction, and the upper guide portion is formed above the lower end of the opening of the first port and between the axis of the first port and an imaginary line that is parallel to the axis of the first port and passes through the opening of the second port when viewed along the first direction.

7. A diaphragm type pressure measurement chamber as set forth in claim 1, wherein a guide portion having a stepped portion is formed on the inner surface of the housing, and the guide portion has a circumferential guide portion that is located between the axis of the first port and an imaginary line that is parallel to the axis of the first port and passes through the opening of the second port, and that extends from the axis of the first port in a direction approaching the imaginary line.

8. A diaphragm type pressure measurement chamber as set forth in claim 1, wherein a guide portion having a stepped portion is formed on the inner surface of the housing, and the guide portion has an axial guide portion that extends from the first port in the axial direction of the first port when viewed from a first direction.

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