Diaphragm-type pressure measuring chamber

Abstract

This invention provides a diaphragm-type pressure measuring chamber that can improve the accuracy of pressure measurement and suppress kinking in the tube. [Solution] The pressure measuring chamber 3 comprises a housing 31 having a chamber body 29 that forms a chamber space 30, and a flexible diaphragm 32 that divides the chamber space 30 into a liquid chamber 30a and an air chamber 30b. The housing 31 has a first port P1 connected to the chamber body 29 that allows blood to flow into the liquid chamber 30a, a second port P2 connected to the chamber body 29 that allows blood to flow out of the liquid chamber 30a, and a third port P3 whose one end is connected to the chamber body 29 and communicates with the air chamber 30b, and whose other end is connected to the pressure receiving port of the pressure measuring device via a flexible tube. The housing 31 is provided with an engaged portion 33 that engages with an engaging portion of the pressure measuring device.

Description

Technical Field

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

Background Art

[0002] There is a blood purification therapy in which a patient's blood is circulated extracorporeally and purified during the circulation. As an example of such a treatment, dialysis therapy is known. In dialysis therapy, blood drawn from a patient is introduced into a dialyzer, where unnecessary components in the blood are replaced with useful components in the dialysate and filtration is also performed, and the treated blood is returned to the patient again. Further, in dialysis therapy, in order to prevent damage to useful blood cells and aggregation of blood, the pressure of the blood is measured at various points in the blood circuit through which the blood flows. For measuring the pressure at various points in such a blood circuit, for example, a pressure measurement chamber as described in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the chamber of Patent Document 1, the internal space of the housing is partitioned into an air chamber and a blood chamber by a diaphragm, and a flexible line communicating with the air chamber is integrally provided in the housing. Then, by connecting the connector at the end of the flexible line to the port of the pressure measuring device, the blood pressure is measured.

[0005] While the chamber provided with this flexible line can shorten the circuit length through which the blood flows, due to the weight of the chamber or the like, there is a risk that the boundary between the tube and the connector of the flexible line will bend and kink.

[0006] Therefore, the objective of this disclosure is to provide a diaphragm-type pressure measuring chamber that can improve the accuracy of pressure measurement and suppress kinking in the tube. [Means for solving the problem]

[0007] A pressure measuring chamber according to a first aspect of the present disclosure is a diaphragm-type pressure measuring chamber for measuring the pressure of blood in a blood circuit, connected to a fluid delivery device having a pressure receiving port, comprising: a housing having a chamber body that forms a chamber space inside; and a flexible diaphragm that divides the chamber space into a liquid chamber and an air chamber, wherein the housing has a first port connected to the chamber body for blood flowing into the liquid chamber, a second port connected to the chamber body for blood flowing out of the liquid chamber, and a third port, one end of which is connected to the chamber body and communicates with the air chamber, and the other end of which is connected to the pressure receiving port via a flexible tube, wherein the housing is provided with an engaged portion that engages with an engaged portion of the pressure measuring device when the third port is connected to the pressure receiving port, and the engagement portion engages with the engaged portion to restrict the downward displacement of the chamber body in the direction of gravity.

[0008] Thus, in the pressure measuring chamber of this disclosure, the chamber's air chamber is connected to the pressure-receiving port of the pressure measuring device via a flexible tube, while the housing is fixed to the pressure measuring device via an engaging portion and an engaged portion. This prevents the entire weight of the housing, including the liquid inside, from being applied to the flexible tube, thereby suppressing kinking of the tube.

[0009] Furthermore, in the second aspect of the present disclosure, the pressure measuring chamber may be configured such that, in the first aspect, the engaged portion is positioned closer to the pressure measuring device than the air chamber when engaged with the engaged portion.

[0010] As a result, the chamber engages with the pressure measuring device on the liquid chamber side, where blood flows in and makes it heavier. This brings the center of gravity of the chamber closer to the engagement point. Therefore, compared to cases where the center of gravity of the chamber is farther from the engagement point, such as when engagement occurs on the air chamber side, the engagement state can be stabilized. Furthermore, if a sensor other than the pressure sensor is installed near the engagement point of the pressure measuring device, it becomes possible to measure the state of the blood in the liquid chamber. For example, by installing an infrared sensor to monitor the blood, it is possible to measure blood oxygen concentration simultaneously with pressure measurement.

[0011] Furthermore, in the first embodiment, the pressure measuring chamber according to a third aspect of the present disclosure comprises a housing having a first case that forms the liquid chamber with the diaphragm, and a second case connected to the first case and forming the air chamber with the diaphragm, wherein the diaphragm has a clamped portion that is sandwiched between the first case and the second case, and the third port is connected to the second case, and the engaged portion may be a convex or concave portion provided on the first case.

[0012] In this case, the engagement operation between the chamber and the device becomes easier. Specifically, when the connector at the end of the flexible tube is connected to the pressure-receiving port, the second case naturally faces upward in the direction of gravity. Therefore, when the user lowers their hand from near the pressure-receiving port and grasps the chamber, they will be gripping the second case, and the user can engage the chamber with the device without readjusting their grip on the chamber.

[0013] Furthermore, in the pressure measuring chamber according to the fourth aspect of the present disclosure, in the first aspect, the engaged portion may be configured such that the second port communicates with the upper vertical portion of the liquid chamber when engaged with the engaged portion.

[0014] This allows air bubbles in the liquid chamber to escape more easily through the second port due to buoyancy when priming the pressure-measuring chamber connected to the blood circuit by injecting saline solution or the like, thus enabling smoother priming.

[0015] Furthermore, in the fifth aspect of the present disclosure, the pressure measuring chamber may, in the first aspect, be configured such that the engaged portion can rotate the housing while maintaining the engaged state with the engaged portion.

[0016] When priming a pressure measuring chamber by injecting saline solution or the like, air bubbles may accumulate in the liquid chamber. In such cases, with the chamber configured as described above, these air bubbles can be easily removed by rotating (oscillating) the housing in one direction and the other while it remains engaged with the pressure measuring device.

[0017] Furthermore, in the pressure measuring chamber according to the sixth aspect of the present disclosure, in the first aspect, the engaged portion may be configured such that, when engaged with the engaged portion, the liquid chamber is located vertically below the air chamber.

[0018] This configuration makes it easier to control the blood flow within the fluid chamber and suppress the formation of blood clots due to blood stagnation within the fluid chamber, compared to a configuration where the air chamber is located vertically below the fluid chamber.

[0019] Furthermore, in the first embodiment of the pressure measuring chamber according to the seventh aspect of the present disclosure, the connection hole of the flexible tube in the third port may be configured such that the engaged portion faces the pressure receiving port when the engaged portion is engaged with the engaging portion.

[0020] This makes it easier to recognize the destination of the tube extending from the third port (i.e., the pressure-receiving port) when the chamber is engaged with the engagement part of the pressure measuring device. In addition, bending of the tube connecting the third port and the pressure-receiving port can be suppressed, thus preventing kinking of the tube.

[0021] The pressure measurement chamber according to the eighth aspect of the present disclosure is a diaphragm type pressure measurement chamber that is connected to a liquid delivery device having a pressure receiving port and measures the pressure of blood in a blood circuit, and has a housing having a chamber body that forms a chamber space inside, and a flexible diaphragm that partitions the chamber space into a first chamber and a second chamber. The housing has a port that is connected to the chamber body and communicates with the first chamber, and a pressure monitor port that has one end connected to the chamber body and communicates with the second chamber and the other end connected to the pressure receiving port via a flexible tube. The housing is provided with an engaged portion that is engaged with an engaging portion of the liquid delivery device in a state where the pressure monitor port is connected to the pressure receiving port, and the engaging portion engages with the engaged portion to restrict the downward displacement of the chamber body in the gravitational direction.

[0022] Thereby, the above pressure measurement chamber can be used, for example, by being interposed between a drip chamber and a pressure receiving port of a liquid delivery device. And even in such a case, the same operational effects as those of the pressure measurement chamber according to the first aspect can be obtained.

Advantages of the Invention

[0023] According to the present disclosure, it is possible to provide a diaphragm type pressure measurement chamber capable of improving the measurement accuracy of pressure and suppressing kinks in a tube.

Brief Description of the Drawings

[0024] [Figure 1] FIG. 1 is a perspective view showing the configuration of a pressure measurement system according to Embodiment 1. [Figure 2] FIG. 2A is an external view of the pressure measurement chamber when viewed from the third direction, and FIG. 2B is a cross-sectional view of the pressure measurement chamber when cut along a plane orthogonal to the left-right direction along the cutting line B-B of FIG. 2A. [Figure 3]FIG. 3A is a perspective view showing a pressure measuring device including an engagement mechanism and a pressure measuring chamber, and FIG. 3B is a cross-sectional view showing the engagement mechanism when cut along a plane orthogonal to the left-right direction. [Figure 4] FIG. 4A is a cross-sectional view showing a configuration according to Modification Example 1 of the engagement mechanism, and FIG. 4B is a cross-sectional view showing a configuration according to Modification Example 2 of the engagement mechanism. [Figure 5] FIG. 5A is a perspective view showing a configuration of a pressure measurement system according to Embodiment 2, showing a disengaged state of the pressure measuring device and the pressure measuring chamber, FIG. 5B is a perspective view showing an engaged state of the pressure measuring device and the pressure measuring chamber, and FIG. 5C is a front view showing an engaged state of the pressure measuring device and the pressure measuring chamber. [Figure 6] FIG. 6A is a perspective view showing a pressure measuring device including an engagement mechanism and a pressure measuring chamber, and FIG. 6B is a cross-sectional view showing the engagement mechanism when cut along a plane orthogonal to the left-right direction. [Figure 7] FIG. 7A is a perspective view showing a pressure measuring device and a pressure measuring chamber in a disengaged state, and FIG. 7B is a perspective view showing a pressure measuring device and a pressure measuring chamber in an engaged state. [Figure 8] FIG. 8A is a perspective view showing the pressure measuring chamber from the back side, and FIG. 8B is a cross-sectional view showing the engagement mechanism when cut along a plane orthogonal to the left-right direction. [Figure 9] FIG. 9A is a perspective view showing a configuration of a pressure measurement system according to Embodiment 5, showing a disengaged state of the pressure measurement assumption and the pressure measuring chamber, and FIG. 9B is a cross-sectional view of the engagement mechanism when cut along a plane orthogonal to the up-down direction. <� [Figure 10] FIG. 10A is a perspective view showing a pressure measuring device and a pressure measuring chamber in an engaged state for a pressure measurement system according to Embodiment 6, and FIG. 10B is a plan view thereof as viewed from above. [Figure 11] FIG. 11 is a perspective view of a pressure measuring device and a pressure measuring chamber in an engaged state as viewed from the rear (inward of the pressure measuring device). Embodiments for Carrying Out the Invention

[0025] (Embodiment 1) A pressure measuring chamber according to an embodiment of this disclosure will be described with reference to the drawings. Note that the pressure measuring chamber described below is only one embodiment of this disclosure. Therefore, this disclosure is not limited to the following embodiments, and additions, deletions, or modifications to the configuration are possible without departing from the spirit of the disclosure.

[0026] A dialysis system used in dialysis therapy is equipped with a blood circuit and a fluid delivery device (console). The blood circuit includes, for example, a blood withdrawal line that leads the patient's blood out of the body, a filter connected to the blood withdrawal line that transfers specific components from the patient's blood into the dialysate to purify the blood, and a blood return line that returns the purified blood to the patient.

[0027] The fluid delivery device is specifically a blood processing device that delivers and processes blood, and is for example, called a dialysis machine. The dialysis machine is equipped with a blood pump interposed in the blood withdrawal line to adjust the flow rate of blood in the blood withdrawal line. The dialysis machine also has various functions, such as measuring and monitoring the blood pressure at various points in the blood circuit, and monitoring the temperature of the dialysate and the amount of anticoagulant injected. In this embodiment, the configuration for measuring blood pressure in such a dialysis machine is called the pressure measuring device 2. The pressure measuring device 2 may be incorporated into the blood processing device, or it may be located separately outside the blood processing device and transmit pressure information to the blood processing device. In other words, the pressure measuring device 2 is the pressure measuring function in the fluid delivery device.

[0028] The pressure measuring device 2 is equipped with one or more pressure sensors 13, which are connected to various points (pressure measurement locations) in the blood circuit via a pressure monitoring line. A pressure measuring chamber 3 is provided between this pressure monitoring line and the pressure measurement locations in the blood circuit. In this disclosure, the pressure measuring device 2 and the pressure measuring chamber 3 together are referred to as the pressure measuring system 1. That is, the dialysis system is equipped with a blood circuit and a dialysis machine, and the pressure measuring system 1 is composed of the pressure measuring device 2, which realizes some functions of the dialysis machine, and the pressure measuring chamber 3, which forms part of the blood circuit.

[0029] The pressure measuring chamber 3 is installed in the blood circuit in the middle of the blood flow line, forming part of that line. In this case, blood flows through the inside of the pressure measuring chamber 3 (liquid chamber 30a described later). It is also possible to install the pressure measuring chamber 3 so as to be connected to another line that branches off from the blood flow line in the blood circuit via a drip chamber or the like.

[0030] Figure 1 is a perspective view showing the configuration of the pressure measurement system 1. As described above, the pressure measurement system 1 comprises a pressure measuring device 2 and a pressure measuring chamber 3. Note that the pressure measuring device 2 in Figure 1 is only partially shown, showing the part to which the pressure measuring chamber 3 is connected. As shown in Figure 1, the pressure measuring device 2 has a housing wall 10 that forms a plane including the first and second directions (a plane perpendicular to the third direction). This housing wall 10 is provided with an engagement portion 11 to which the pressure measuring chamber 3 is attached, and a pressure receiving port 12 that is connected to the third port (pressure monitor port) P3 of the pressure measuring chamber 3 via a flexible tube T3. The pressure receiving port 12 is in communication with the pressure sensor 13.

[0031] Let's discuss the directions here. Figure 1 shows the directions (i.e., directions related to the pressure measuring system 1) when the pressure measuring chamber 3 is connected to the pressure measuring device 2, including a first and second direction which are orthogonal to each other, and a third direction which is orthogonal to both the first and second directions. Of these, the first direction is typically the up-and-down direction, the second direction is the left-and-right direction, and the third direction is the front-and-back direction. In this case, the pressure measuring system 1 shown in Figure 1 has a pressure receiving port 12 positioned above the engagement portion 11.

[0032] Note that the first to third directions are not limited to the orientations described above. For example, the first direction may be the front-to-back direction, the second direction the left-to-right direction, and the third direction the up-and-down direction. In this case, the housing wall 10 will face upwards, and the pressure measuring chamber 3 will be attached to the engagement portion 11 so that it is positioned above the housing wall 10. Furthermore, unlike the two examples above, the third direction may be set to be inclined in both the up-and-down and front-to-back directions.

[0033] [Pressure measuring chamber] Figure 2A is an external view of the pressure measuring chamber 3, showing its configuration as seen from a third direction, and Figure 2B is a cross-sectional view of the pressure measuring chamber 3, showing its configuration when cut along the cutting line BB of Figure 2A with a plane perpendicular to the left-right direction. The configuration of the pressure measuring chamber 3 will be described in detail below. In the following description (including other embodiments), when referring to directions in relation to the configuration of the pressure measuring chamber 3, for convenience, the front-back direction, left-right direction, and up-down direction will be defined as shown in Figures 2A and 2B.

[0034] The pressure measuring chamber 3 comprises a housing 31 having a chamber body 29 that forms a chamber space 30 inside, and a flexible diaphragm 32 that divides the chamber space 30 into a liquid chamber (first chamber) 30a and an air chamber (second chamber) 30b. The housing 31 is provided with an engaged portion 33 that engages with an engaging portion 11 of the pressure measuring device 2. The pressure measuring chamber 3 also has first to third ports connected to the housing 31.

[0035] The first port P1 has one end connected to the chamber body 29 and communicating with the liquid chamber 30a, and the other end is detachably connected to a tube T1 that forms a blood circuit, allowing blood to flow from tube T1 into the liquid chamber 30a. The second port P2 has one end connected to the chamber body 29 and communicating with the liquid chamber 30a, and the other end is detachably connected to a tube T2 that forms a blood circuit, allowing blood to flow from the liquid chamber 30a into tube T2. The third port P3 has one end connected to the chamber body 29 and communicating with the air chamber 30b, and the other end is connected to the pressure receiving port 12 via a detachably connected tube T3 (pressure monitoring line).

[0036] As shown in Figures 2A and 2B, the chamber body 29 has a flattened spherical shape with a small vertical dimension and is composed of a lower first case 35 and an upper second case 36, both made of transparent resin. The diaphragm 32 is provided sandwiched between the first case 35 and the second case 36. Accordingly, the liquid chamber 30a is formed between the inner surface of the first case 35 and the lower surface of the diaphragm 32, and the air chamber 30b is formed between the inner surface of the second case 36 and the upper surface of the diaphragm 32.

[0037] A first port P1 is connected to the rear of the first case 35, a second port P2 is connected to the front of the first case 35, and a third port P3 is connected to the top of the second case 36. The first port P1 opens towards the rear, while the second port P2 and the third port P3 open towards the front. When viewed along the vertical direction, the axis of the third port P3 is positioned to pass through the center CP of the chamber body 29. On the other hand, the axes of the first port P1 and the second port P2 do not pass through the center CP and are located to the left and right of the center CP. Specifically, the first port P1 is located to the right of the center CP, and the second port P2 is located to the left of the center CP.

[0038] The first case 35 has a first main body portion 40 that forms a dome shape that bulges downward, and a first circumferential portion 41 that circles around the periphery of the first main body portion 40. The first circumferential portion 41 has a first circumferential protrusion 42 that projects upward and circles around the first main body portion 40, and a first circumferential groove portion 43 that is located outside the first circumferential protrusion 42 and is recessed downward. On the other hand, the second case 36 has a second main body portion 45 that forms a dome shape that bulges upward, and a second circumferential portion 46 that circles around the periphery of the second main body portion 45. The second circumferential portion 46 has a second circumferential protrusion 47 that projects downward and circles around the second main body portion 45, and a second circumferential groove portion 48 that is located outside the second circumferential protrusion 47 and is recessed upward.

[0039] The diaphragm 32 has a dome-shaped membrane portion 50 and a clamped portion 51 that extends outward (in the expanding radial direction) from the periphery of the membrane portion 50 and forms an annular shape. The diaphragm 32 also has an annular support frame 52 provided on the periphery of the clamped portion 51. The support frame 52 is larger in the vertical direction than the clamped portion 51. The membrane portion 50 and the clamped portion 51 are integrally formed from the same highly flexible material, for example, while the support frame 52 is formed from a material that is less flexible than the membrane portion 50 and the clamped portion 51. The membrane portion 50, the clamped portion 51, and the support frame 52 may be integrally formed by two-color molding.

[0040] The clamped portion 51 of the diaphragm 32 is clamped between the first circumferential portion 41 of the first case 35 and the second circumferential portion 46 of the second case 36, and the support frame 52 is supported. Specifically, when the first case 35 and the second case 36 are placed facing each other, the first circumferential protrusion 42 and the second circumferential protrusion 47 face each other in the vertical direction. The clamped portion 51 of the diaphragm 32 is then clamped from above and below by these first circumferential protrusion 42 and the second circumferential protrusion 47. Also, when the first case 35 and the second case 36 are placed facing each other, the first circumferential groove 43 and the second circumferential groove 48 face each other in the vertical direction, forming an annular space between them. The support frame 52 of the diaphragm 32 is then housed and supported in this annular space.

[0041] In this state, for example, the first circumferential portion 41 and the second circumferential portion 46 are ultrasonically welded or bonded to the appropriate locations, thereby integrating the first case 35, the second case 36, and the diaphragm 32 to form the pressure measuring chamber 3. Therefore, in the pressure measuring chamber 3, the liquid chamber 30a through which blood flows is located below the air chamber 30b, and the liquid chamber 30a and the air chamber 30b are airtight and liquid-tightly separated by the diaphragm 32.

[0042] As mentioned above, the pressure measuring chamber 3 can also be configured to connect to another line branching off from the blood flow line in the blood circuit via a drip chamber or the like. In this case, the liquid chamber (first chamber) 30a of the chamber space 30 communicates with the gas layer of the drip chamber via the first port P1. Therefore, since blood does not flow into the liquid chamber (first chamber) 30a, it functions as "another gas chamber" separate from the gas chamber (second chamber) 30b. Furthermore, when used via a drip chamber, the second port P2 is not essential, so the second port P2 may be blocked, or the second port P2 may not be provided at all in the chamber body 29. It is also possible to configure it to connect to another line branching off from the blood flow line in the blood circuit via a T-tube, and in this case as well, the second port P2 may not be provided.

[0043] [Engagement mechanism] The pressure measuring chamber 3 has an engaged portion 33 that engages with the engaging portion 11 of the pressure measuring device 2. Here, the engaging portion 11 and the engaged portion 33 together are referred to as the engagement mechanism 4, and this engagement mechanism 4 will be described below. Figure 3A is a perspective view showing the pressure measuring device 2 and the pressure measuring chamber 3 including the engagement mechanism 4, and Figure 3B is a cross-sectional view showing the engagement mechanism 4, showing the configuration when cut by a plane perpendicular to the left-right direction. Note that Figures 3A and 3B illustrate the orientation of the pressure measuring device 2 and the pressure measuring chamber 3, with the third direction in Figure 1 being the front-back direction.

[0044] An engaging portion 11 is provided on the housing wall 10 of the pressure measuring device 2. The engaging portion 11 has an outer cylindrical portion 60, and the outer cylindrical portion 60 is projected from the surface of the housing wall 10 with its axis perpendicular to the housing wall 10. On the other hand, an engaged portion 33 is provided at the bottom of the first case 35 of the pressure measuring chamber 3. The engaged portion 33 has a convex inner cylindrical portion 70, and the inner cylindrical portion 70 is projected downward from the bottom surface of the first case 35 with its axis oriented in the vertical direction.

[0045] The height dimension of the outer cylindrical portion 60 and the height dimension of the inner cylindrical portion 70 are almost identical. Also, the inner diameter dimension of the outer cylindrical portion 60 and the outer diameter dimension of the inner cylindrical portion 70 are almost identical. Therefore, the inner cylindrical portion 70 can be tightly fitted inside the outer cylindrical portion 60. In this fitted state, the inner circumferential surface 61 of the outer cylindrical portion 60 and the outer circumferential surface 71 of the inner cylindrical portion 70 are in contact with a predetermined pressure, so that the fitted position (i.e., the engagement position of the pressure measuring chamber 3 with respect to the pressure measuring device 2) can be maintained against a predetermined external force. Thus, in this embodiment, the engagement state between the engaging portion 11 and the engaged portion 33 is realized in the assembled state in which the inner cylindrical portion 70 is fitted into the outer cylindrical portion 60. As a result, the housing 31 of the pressure measuring chamber 3 is restricted not only from displacement downward in the direction of gravity, but also from displacement in the front-rear and lateral directions.

[0046] Furthermore, when cut by a plane perpendicular to the axis, the inner contour of the outer cylindrical portion 60 is perfectly circular, and similarly, when cut by a plane perpendicular to the axis, the outer contour of the inner cylindrical portion 70 is also perfectly circular. Therefore, with the inner cylindrical portion 70 fitted into the outer cylindrical portion 60, both can rotate around their respective axes. Thus, while maintaining the engaged state by the engagement mechanism 4, the pressure measuring chamber 3 is rotatable relative to the pressure measuring device 2. In this embodiment, the axis of the inner cylindrical portion 70 of the engaged portion 33 coincides with a virtual line LC in the vertical direction passing through the center CP of the chamber body 29 (see Figure 2B).

[0047] In the engagement mechanism 4 described above, the pressure measuring chamber 3 is engaged with the pressure measuring device 2 by engaging the engaging portion 11 and the engaged portion 33 with each other (see Figure 3B). That is, with the third port (pressure monitor port) P3 communicating with the air chamber 30b connected to the pressure receiving port 12 via the tube T3, the housing 31 of the pressure measuring chamber 3 is engaged with the housing wall 10 of the pressure measuring device 2 by the engagement mechanism 4 (see Figure 1).

[0048] As a result, the housing 31 is fixed to the pressure measuring device 2, which suppresses displacement of the housing 31 that would cause kinking in the tubes T1 to T3 (for example, displacement downward in the direction of gravity).

[0049] Furthermore, in the pressure measuring chamber 3 according to this embodiment, the engaged portion 33 is located in the vertical direction opposite to the third port P3 relative to the clamped portion 51 of the diaphragm 32. That is, the engaged portion 33 is located below the clamped portion 51. To put it another way, the engaged portion 33 is located on the liquid chamber 30a side of the housing 31 rather than the air chamber 30b side, and is specifically provided in the first case 35. Here, since blood flows into the liquid chamber 30a during dialysis treatment, the center of gravity of the housing 31 is located in a position that is biased towards the liquid chamber 30a side rather than the air chamber 30b side. Therefore, by providing the engaged portion 33 closer to the center of gravity and engaging it with the engaging portion 11, the pressure measuring chamber 3 can be supported more stably.

[0050] Furthermore, in the engagement state described above, the pressure measuring system 1 according to this embodiment has the liquid chamber 30a located closer to the pressure measuring device 2 (here, the housing wall 10) than the air chamber 30b. Therefore, if a blood sensor 14 (see Figure 3B) is provided inside the housing wall 10 corresponding to the engagement portion 11, the state of the blood in the liquid chamber 30a can also be measured by this blood sensor 14. For example, if an infrared sensor is used as the blood sensor 14, the blood oxygen concentration of the blood in the liquid chamber 30a can be measured. Thus, the pressure measuring device 2 may be equipped with such a blood sensor 14 inside the housing wall 10 corresponding to the engagement portion 11. The configuration of the pressure measuring chamber 3 that is more preferable for measuring the state of the blood by the blood sensor 14 provided in the pressure measuring device 2 will be described later with reference to Figure 9B, etc.

[0051] Furthermore, as described above, the housing 31 of the pressure measuring chamber 3 can be rotated around the central axis CP relative to the pressure measuring device 2 while maintaining the engaged state. This facilitates priming of the pressure measuring chamber 3. That is, the blood circuit to which the pressure measuring chamber 3 is connected is primed by injecting physiological saline solution, etc. At this time, air bubbles may remain in the liquid chamber 30a, but by rotating (oscillating) the housing 31, the air bubbles can be easily discharged from the second port P2.

[0052] Furthermore, when the pressure measuring chamber 3 is attached to the pressure measuring device 2 by engaging the engaged portion 33 with the engaging portion 11, the connection hole 28 of the tube T3 at the third port P3 can be directed toward the pressure receiving port 12. Therefore, when the pressure measuring chamber 3 is engaged with the pressure measuring device 2, the pressure receiving port 12 is easily recognized as the connection destination for the tube T3 extending from the third port P3, allowing the user to perform the connection work smoothly. In addition, because the third port P3 faces the pressure receiving port 12, unnecessary bending of the tube T3 connecting the two can be suppressed, preventing the occurrence of kinks.

[0053] In the above, a cylindrical configuration was exemplified for the engaged portion 33, but it is not limited to this, and a columnar configuration may also be adopted. Also, in the above, a configuration in which a small-diameter cylindrical engaged portion 33 is fitted inside a large-diameter cylindrical engaging portion 11 was exemplified, but it is not limited to this, and a configuration in which a small-diameter cylindrical engaging portion 11 is fitted inside a large-diameter cylindrical engaged portion 33 may also be adopted. Also, in the above, a configuration in which the engaged portion 33 is convex and the engaging portion 11 is concave was exemplified, but it is not limited to this, and the convex and concave shapes may be reversed so that the engaged portion 33 is concave and the engaging portion 11 is convex. In this case, for example, the inner and outer relationship between the outer cylindrical portion 60 of the engaging portion 11 and the inner cylindrical portion 70 of the engaged portion 33 may be reversed. That is, the engaging portion 11 may have an inner cylindrical portion, and the engaged portion 33 may have an outer cylindrical portion that can be tightly fitted onto the inner cylindrical portion. Furthermore, the specific shape of the convex and concave portions of the engaged portion 33 is not particularly limited. In other words, in addition to annular protrusions such as the inner cylindrical portion 70 described above, plate-shaped protrusions, as illustrated later in Figure 7(A), can also be used.

[0054] Furthermore, although the above example illustrates a configuration in which the engaged portion 33 is provided on the first case 35, the arrangement of the engaged portion 33 is not limited to this, and it may also be provided on the second case 36. Also, the engaged portion 33 may be provided on the housing 31, and therefore, for example, one or more of the first port P1, second port P2, and third port P3 may be designated as the engaged portion 33 and a configuration in which they are engaged with the engaging portion 11 may be adopted. Also, although the above example shows the use of fitting as the engagement between the engaging portion 11 and the engaged portion 33, it is not limited to this. Furthermore, it is more preferable to have a configuration that can restrict the displacement of the chamber body 29 in directions other than the direction of gravity, such as the lateral and front-rear directions. In this case, kinking caused by the housing 31 being displaced, such as when a user touches a tube or the like connected to the pressure measuring chamber 3, can also be avoided. As illustrated in this embodiment, this can be achieved by employing fitting assembly or locking assembly for the engagement between the engaging portion 11 and the engaged portion 33.

[0055] (Variation 1) Figure 4A is a cross-sectional view showing the configuration of Modified Example 1 of the engagement mechanism 4. Similar to Embodiment 1, the engagement mechanism 4 of Modified Example 1 includes an engagement portion 11 having an outer cylindrical portion 60 and an engaged portion 33 having an inner cylindrical portion 70. On the other hand, in the engagement mechanism 4 of Modified Example 1, a circumferential groove 61a is formed on the inner circumferential surface 61 of the outer cylindrical portion 60, and a circumferential groove 71a is also formed on the outer circumferential surface 71 of the inner cylindrical portion 70.

[0056] Of these, the circumferential groove 61a is formed on the innermost part (adjacent to the bottom surface 62) of the inner circumferential surface 61 of the outer cylindrical portion 60. The circumferential groove 71a is formed on the outer circumferential surface 71 of the inner cylindrical portion 70 in the part adjacent to the tip. In other words, the circumferential groove 71a is formed in the inner cylindrical portion 70 by cutting out the tip portion of its outer circumferential surface 71 and the outer edge portion of the tip surface 72.

[0057] These circumferential grooves 61a and 71a are positioned opposite each other when the engaging portion 11 and the engaged portion 33 are engaged. In this opposing position, the circumferential grooves 61a and 71a form an annular space, and the O-ring 55 is housed in this annular space.

[0058] In the engagement mechanism 4 according to this modified example 1, an O-ring 55 is interposed between the outer cylindrical portion 60 and the inner cylindrical portion 70 as described above. As a result, the O-ring 55 is compressed and held between the outer cylindrical portion 60 and the inner cylindrical portion 70, improving the engagement force (fixing force) between the engaging portion 11 and the engaged portion 33. Furthermore, the interposition of the O-ring 55 makes it easier for the engaging portion 11 and the engaged portion 33 to rotate relative to each other around their axes.

[0059] (Modification 2) Figure 4B is a cross-sectional view showing the configuration of a modified example 2 of the engagement mechanism 4. Similar to embodiment 1, the engagement mechanism 4 of modified example 2 includes an engagement portion 11 having an outer cylindrical portion 60 and an engaged portion 33 having an inner cylindrical portion 70. On the other hand, in the engagement mechanism 4 of modified example 2, a circumferential protrusion 61b is formed on the inner circumferential surface 61 of the outer cylindrical portion 60, and a circumferential recess 71b is formed on the outer circumferential surface of the inner cylindrical portion 70.

[0060] Of these, the circumferential projection 61b is formed near the midpoint in the direction along the axis of the inner circumferential surface 61 of the outer cylindrical portion 60. Similarly, the circumferential recess 71b is formed near the midpoint in the direction along the axis of the outer circumferential surface 71 of the inner cylindrical portion 70. When the engaging portion 11 and the engaged portion 33 are engaged, the circumferential projection 61b and the circumferential recess 71b are positioned opposite each other, and the circumferential projection 61b engages (fits) with the circumferential recess 71b.

[0061] In the engagement mechanism 4 according to this modified example 2, when the engaging portion 11 and the engaged portion 33 are engaged, the circumferential projection 61b fits into the circumferential recess 71b. Therefore, the engaged portion 33 can be prevented from coming loose from the engaging portion 11, and a stable engagement state can be achieved. Furthermore, because the circumferential projection 61b and the circumferential recess 71b fit together, the engaging portion 11 and the engaged portion 33 can rotate relative to each other around their axes even when engaged.

[0062] Furthermore, in the inner cylindrical portion 70, the portion closer to the tip of the circumferential recess 71b has a smaller outer diameter than the portion further inside the circumferential recess 71b. Therefore, when fitting the inner cylindrical portion 70 into the outer cylindrical portion 60, interference between the tip portion of the inner cylindrical portion 70 and the circumferential protrusion 61b of the outer cylindrical portion 60 is reduced, making fitting easier. Alternatively, the recess and protrusion may be reversed. That is, a circumferential recess may be formed on the inner circumferential surface 61 of the outer cylindrical portion 60, and a circumferential protrusion may be formed on the outer circumferential surface 71 of the inner cylindrical portion 70, and these circumferential recess and circumferential protrusion may be engaged.

[0063] (Variation 3) The above describes a case in which the pressure measuring chamber 3 is mounted on the front of the housing wall 10 facing forward in the pressure measuring device 2, with its lower part (bottom) facing rearward. However, the device is not limited to this. For example, the pressure measuring device 2 may have a housing wall 10 facing upward, and an engaging portion 11 may be provided on the upper surface of this housing wall 10. The pressure measuring chamber 3 may then be mounted to such an engaging portion 11 with the engaged portion 33 facing downward (with the bottom facing downward). In other words, the third direction in Figure 1 may be the vertical direction.

[0064] In this case, the engagement mechanism 4 is configured such that, in the engaged state where the engaged portion 33 is engaged with the engagement portion 11, the liquid chamber 30a is located vertically below the air chamber 30b. This makes it easier to control the blood flow in the liquid chamber 30a as intended, compared to the case where the air chamber 30b is located vertically below the liquid chamber 30a, and also prevents components with a high specific gravity, such as blood cells in the blood, from settling in the air chamber 30b, thereby suppressing the formation of thrombi due to blood stagnation in the liquid chamber 30a.

[0065] (Embodiment 2) Figure 5A is a perspective view showing the configuration of the pressure measuring system 1A according to Embodiment 2, and shows the unengaged state of the pressure measuring device 2A and the pressure measuring chamber 3A that constitute the pressure measuring system 1A. Figure 5B is a perspective view showing the engaged state of the pressure measuring device 2A and the pressure measuring chamber 3A, and Figure 5C is a front view of the engaged state. Figures 5A to 5C illustrate the orientation of the pressure measuring device 2A and the pressure measuring chamber 3A, with the third direction in Figure 1 being the front-rear direction.

[0066] The pressure measuring system 1A according to Embodiment 2 has the same configuration as Embodiment 1 for the pressure measuring chamber 3A, but the pressure measuring device 2A differs slightly from the configuration of Embodiment 1. In particular, it is equipped with an engagement mechanism 4A with a different configuration from the engagement mechanism 4 of Embodiment 1. The following will describe the differences in detail. The pressure measuring device 2A of Embodiment 2 has a housing wall 10 and an outer cylindrical portion 60 protruding from the housing wall 10, similar to the pressure measuring device 2 of Embodiment 1. Furthermore, the pressure measuring device 2A has two arc-shaped wall portions 63 and 64.

[0067] The arc-shaped wall portions 63 and 64 are shaped along the same circumference centered on the outer cylindrical portion 60 and are erected on the surface of the housing wall 10 so as to protrude in the same direction as the outer cylindrical portion 60. The arc-shaped wall portions 63 and 64 are located opposite each other on either side of the outer cylindrical portion 60 and have a circumference of approximately 45 to 60 degrees with respect to the outer cylindrical portion 60.

[0068] These arc-shaped wall portions 63 and 64 contact the circumferential surface 31a of the housing 31 when the inner cylindrical portion 70 is fitted into the outer cylindrical portion 60, that is, when the pressure measuring device 2A and the pressure measuring chamber 3A are engaged. Thus, the arc-shaped wall portions 63 and 64 have a height dimension that extends from the surface of the housing wall 10 to the circumferential surface 31a of the housing 31 of the pressure measuring chamber 3A in the engaged state.

[0069] In the engagement state shown in Figure 5C, the second port P2 of the pressure measuring chamber 3A is oriented vertically upward. At this time, the first port P1 is oriented vertically downward. When viewed directly facing the housing wall 10 as shown in Figure 5C, the lower arc-shaped wall portion 63 has one end 63a (right end) in the circumferential direction that abuts the left wall surface of the first port P1, and the other end 63b (left end) is positioned clockwise relative to the first end 63a. The upper arc-shaped wall portion 64 has one end 64a (left end) in the circumferential direction that abuts the right wall surface of the second port P2, and the other end 64b (right end) is positioned clockwise relative to the first end 64a.

[0070] With this configuration, the pressure measuring chamber 3A is engaged with the outer cylindrical portion 60 by the inner cylindrical portion 70 fitting inside it, and the circumferential surface 31a of the housing 31 is engaged with the inner circumferential surfaces of the arc-shaped wall portions 63 and 64 by contact. Therefore, the pressure measuring chamber 3A is more stably supported by the pressure measuring device 2.

[0071] In Embodiment 2, the outer cylindrical portion 60 and arc-shaped wall portions 63 and 64 of the pressure measuring device 2A form the engaging portion 11. The inner cylindrical portion 70 of the pressure measuring chamber 3A and the circumferential surface 31a of the housing 31 form the engaged portion 33. The engaging mechanism 4A according to Embodiment 2 consists of these engaging portion 11 and engaged portion 33.

[0072] Furthermore, as shown in Figures 5B and 5C, the orientation of the pressure measuring chamber 3A is restricted by the arc-shaped wall portions 63 and 64 when engaged. Specifically, when engaged, the pressure measuring chamber 3A is positioned so that the second port P2 faces upward. At this time, the second port P2 communicates with the upper vertical portion of the liquid chamber 30a. In other words, the engaged portion 33 of the engagement mechanism 4A of Embodiment 2 is configured such that the second port P2 communicates with the upper vertical portion of the liquid chamber 30a when engaged.

[0073] As a result, when priming the pressure measuring chamber 3A connected to the blood circuit by injecting physiological saline solution or the like, air bubbles in the liquid chamber 30a can easily escape from the second port P2 due to buoyancy. Therefore, priming can be performed smoothly.

[0074] In addition, the engagement mechanism 4A of Embodiment 2 is the same as in Embodiment 1 in that the pressure measuring chamber 3A can be rotated (oscillated) relative to the pressure measuring device 2A while maintaining the engaged state. For example, as shown in Figure 5C, the pressure measuring chamber 3A can be rotated clockwise and counterclockwise within a range of approximately 90 degrees, from a position where the axes of the first port P1 and the second port P2 are facing vertically to a position where the axes of the first port P1 and the second port P2 are facing horizontally. Therefore, by oscillating the pressure measuring chamber 3A, air bubbles in the liquid chamber 30a can be guided to the second port P2, making it even easier to remove the air bubbles.

[0075] Furthermore, in the case of the pressure measuring system 1A of Embodiment 2, the pressure measuring chamber 3A, whose orientation is restricted in the engaged state, has the connection hole 28 of the third port P3 facing upward. In other words, the engagement mechanism 4A restricts the orientation of the pressure measuring chamber 3A, which is engaged with the pressure measuring device 2A, so that the third port P3 faces upward. Therefore, if the pressure measuring device 1A is configured such that the pressure receiving port 12 is positioned above the engagement portion 11 as shown in Figure 1, the third port P3 of the pressure measuring chamber 3A in the engaged state faces the pressure receiving port 12. Here, the pressure receiving port 12 side is, for example, the upward side in the direction of gravity in this embodiment. Therefore, in the engaged state, the third port P3 extends upward so that its axis faces the pressure receiving port 12.

[0076] As a result, when the pressure measuring chamber 3 is engaged with the pressure measuring device 2, the pressure receiving port 12 is easily recognized as the connection destination for the tube T3 extending from the third port P3, allowing the user to perform the connection work smoothly. In addition, since the third port P3 faces the pressure receiving port 12, unnecessary bending of the tube T3 connecting the two can be suppressed, preventing the occurrence of kinks.

[0077] Furthermore, the configuration according to this second embodiment can be combined with any one of the above-described modifications 1 to 3. Alternatively, the configuration according to the second embodiment may be combined with the configurations of modifications 1 and 3, or with the configurations of modifications 2 and 3.

[0078] (Embodiment 3) The pressure measuring system 1B according to Embodiment 3 will be described with reference to Figures 6A and 6B. This pressure measuring system 1B comprises a pressure measuring device 2B and a pressure measuring chamber 3B, and further comprises an engagement mechanism 4B that engages the two. The pressure measuring device 2B and pressure measuring chamber 3B are the same as the pressure measuring device 2 and pressure measuring chamber 3 described in Embodiment 1, except for the engagement mechanism 4B. Therefore, the following description will focus on the engagement mechanism 4B.

[0079] Figure 6A is a perspective view showing the pressure measuring device 2B and pressure measuring chamber 3B, including the engagement mechanism 4B, and Figure 6B is a cross-sectional view showing the engagement mechanism 4B, illustrating its configuration when cut by a plane perpendicular to the left-right direction. Figures 6A and 6B illustrate the orientation of the pressure measuring device 2B and pressure measuring chamber 3B, with the third direction in Figure 1 being the front-rear direction. The engagement portion 11 of the pressure measuring device 2B has an outer cylindrical portion 80. The outer cylindrical portion 80 is projected from the surface of the housing wall 10 with its axis perpendicular to the housing wall 10. Notches 81 and 82 are formed in the right and left portions of the outer cylindrical portion 80.

[0080] One of the notches 81 is generally L-shaped and has an opening 81a on the right side of the tip of the outer cylindrical portion 80. The notch 81 extends from this opening 81a along the axial direction to the inner middle portion 81b. The middle portion 81b is located at approximately half the axial length of the outer cylindrical portion 80. Furthermore, the notch 81 extends from the middle portion 81b in one direction in the circumferential direction (clockwise when viewed from the front in Figure 6A) for a length such that the central angle is approximately 90 degrees, reaching the terminal portion 81c. Therefore, the terminal portion 81c of the notch 81 is located at the bottom of the outer cylindrical portion 80.

[0081] The other notch 82 is also L-shaped and has an opening 82a on the left side of the tip of the outer cylindrical portion 80. The notch 82 extends from this opening 82a along the axial direction to the inner intermediate portion 82b. The intermediate portion 82b is located at approximately half the axial length of the outer cylindrical portion 80. Furthermore, the notch 82 extends from the intermediate portion 82b in one direction in the circumferential direction (clockwise when viewed from the front in Figure 6A) for a length such that the central angle is approximately 90 degrees, reaching the terminal portion 82c. Therefore, the terminal portion 82c of the notch 82 is located on the upper part of the outer cylindrical portion 80.

[0082] On the other hand, the engaged portion 33 of the pressure measuring chamber 3B has a convex inner cylindrical portion 90. The inner cylindrical portion 90 is provided so that its axis is oriented vertically and protrudes downward from the bottom surface of the first case 35. Two convex portions 92 and 93 are provided on the outer circumferential surface 91 of this inner cylindrical portion 90. One convex portion 92 is rectangular parallelepiped in shape and protrudes from the outer circumferential surface 91 near the first port P1 (rear part). The other convex portion 93 is rectangular parallelepiped in shape and protrudes from the outer circumferential surface 91 near the second port P2 (front part).

[0083] As described above, the engaging portion 11 and the engaged portion 33 are engaged when the inner cylindrical portion 90 is fitted into the outer cylindrical portion 80 and the protrusions 92 and 93 engage with the notches 81 and 82. To explain in more detail, first, the pressure measuring chamber 3B is positioned so that its engaged portion 33 faces backward and the inner cylindrical portion 90 is coaxial with the outer cylindrical portion 80. Then, the inner cylindrical portion 90 is brought closer to the outer cylindrical portion 80 and the tip of the inner cylindrical portion 90 is fitted into the outer cylindrical portion 80. At this time, the position of the pressure measuring chamber 3B is such that the first port P1 is on the right and the second port P2 is on the left. Then, the protrusion 92 enters the notch 81 from the opening 81a and the protrusion 93 enters the notch 82 from the opening 82a.

[0084] Then, when the protrusion 92 reaches the middle portion 81b of the notch 81 and the protrusion 93 reaches the middle portion 82b of the notch 82, the pressure measuring chamber 3B is rotated clockwise. As a result, the protrusion 92 reaches the end portion 81c of the notch 81 and the protrusion 93 reaches the end portion 82c of the notch 82, completing the engagement between the engaging portion 11 and the engaged portion 33 and entering the engaged state.

[0085] Figure 6B shows the engaged state, in which the pressure measuring chamber 3B has its second port P2 facing upward. Therefore, similar to the pressure measuring system 1A of Embodiment 2, the second port P2 communicates with the upper vertical part of the liquid chamber 30a, making it easier to remove air bubbles from the liquid chamber 30a during priming. Also, the third port P3 faces the upper pressure receiving port 12. Therefore, the pressure receiving port 12 is easily recognized as the connection destination for the tube T3 extending from the third port P3, improving user workability and preventing kinking by suppressing unnecessary bending of the tube T3.

[0086] Furthermore, the configuration according to this third embodiment can be combined with any one of the above-described modifications 1 to 3. Alternatively, the configuration according to the third embodiment may be combined with the configurations of modifications 1 and 3, or with the configurations of modifications 2 and 3.

[0087] (Embodiment 4) The pressure measuring system 1C according to Embodiment 4 will be described with reference to Figures 7A, 7B, 8A, and 8B. This pressure measuring system 1C comprises a pressure measuring device 2C and a pressure measuring chamber 3C, and further comprises an engagement mechanism 4C that engages the two. The pressure measuring device 2C and pressure measuring chamber 3C are the same as the pressure measuring device 2 and pressure measuring chamber 3 described in Embodiment 1, except for the engagement mechanism 4C. Therefore, the following description will focus on the engagement mechanism 4C.

[0088] Figure 7A is a perspective view showing the pressure measuring device 2C and pressure measuring chamber 3C in an unengaged state, and Figure 7B is a perspective view showing the pressure measuring device 2C and pressure measuring chamber 3C in an engaged state. Figure 8A is a perspective view showing the pressure measuring chamber 3C from the rear side, and Figure 8B is a cross-sectional view showing the engagement mechanism 4C, illustrating the configuration when cut by a plane perpendicular to the left-right direction. Figures 7A, 7B, 8A, and 8B illustrate the orientation of the pressure measuring device 2C and pressure measuring chamber 3C with the third direction in Figure 1 being the front-back direction.

[0089] As shown in Figures 7A and 7B, the engagement mechanism 4C is configured to move the pressure measuring chamber 3C from top to bottom along the surface of the housing wall 10 and engage it with the pressure measuring device 2C. More specifically, as shown in Figure 7B, the pressure measuring device 2C has a pair of guide plates 101 and 102. The guide plates 101 and 102 are rectangular plates that extend vertically along the housing wall 10 and are arranged on the left and right sides at a predetermined distance apart, facing each other.

[0090] As shown in Figure 8B, the tip of the left guide plate 101 (the end that moves away from the housing wall 10) is provided with a claw-shaped projection 101a that protrudes to the right, towards the guide plate 102. The claw-shaped projection 101a is formed along the entire length of the guide plate 101, from the upper end to the lower end. Similarly, the tip of the right guide plate 102 has a claw-shaped projection 102a that protrudes to the left, towards the guide plate 101, and is formed along the entire length of the guide plate 102, from the upper end to the lower end.

[0091] Furthermore, as shown in Figure 7A, a stopper 103 is provided below these guide plates 101 and 102 at a predetermined interval. The stopper 103 is a rectangular plate that extends horizontally along the housing wall 10 and has a length approximately the same as the separation dimension of the guide plates 101 and 102. These guide walls 101 and 102 and the stopper 103 constitute the engaging portion 11 of the engaging mechanism 4C.

[0092] On the other hand, as shown in Figure 8A, a pair of guided plates 111 and 112 are provided at the bottom of the first case 35 of the pressure measuring chamber 3C. The guided plates 111 and 112 are rectangular in shape and are positioned opposite each other with a predetermined distance between them. Also, as shown in Figure 8B, a claw-like projection 111a is formed at the tip of the guided plate 111, extending along its entire length and protruding in the opposite direction from the guided plate 112. Similarly, a claw-like projection 112a is formed at the tip of the guided plate 112, extending along its entire length and protruding in the opposite direction from the guided plate 111. These convex guided plates 111 and 112 constitute the engaged portion 33 of the engagement mechanism 4C.

[0093] The pressure measuring device 2C having the engaging portion 11 described above and the pressure measuring chamber 3C having the engaged portion 33 are engaged by sliding against each other. Specifically, with the pressure measuring chamber 3C facing backward toward the housing wall 10 with its lower (bottom) portion facing backward, the pair of guided plates 111 and 122 are brought closer to the pair of guide plates 101 and 102 of the pressure measuring device 2C from above. Then, the pressure measuring chamber 3A is slid downward so that the guided plates 111 and 112 are sandwiched between the guide plates 101 and 102.

[0094] As a result, the guided wall 111 is adjacent to and facing the right of the guide wall 101, and the guided wall 112 is adjacent to and facing the left of the guide wall 102. In addition, the claw portion 101a of the guide wall 101 engages with the claw portion 111a of the guided wall 111, and the claw portion 102a of the guide wall 102 engages with the claw portion 112a of the guided wall 112. Due to this engagement, the guided walls 111 and 112 can move (slide) vertically relative to the guide walls 101 and 102, but cannot move forward away from the housing wall 10.

[0095] Furthermore, the pressure measuring chamber 3C is positioned so that a predetermined part of the housing 31 (for example, the lower end of the guided walls 111, 112) contacts the stopper 103 at a predetermined position in the sliding direction. This determines the vertical position of the pressure measuring chamber 3C when engaged. Thus, the pressure measuring chamber 3C is engaged with the pressure measuring device 2C by sliding it downward, and the engagement is released by sliding it upward when removing it.

[0096] (Embodiment 5) The pressure measurement system 1D according to Embodiment 5 will be described with reference to Figures 9A and 9B. Figure 9A is a perspective view showing the configuration of the pressure measurement system 1D according to Embodiment 5, and shows the unengaged state of the pressure measurement assumption 2D and the pressure measurement chamber 3D. Figure 9B is a cross-sectional view of the engagement mechanism 4D, showing the configuration when cut by a plane perpendicular to the vertical direction.

[0097] This pressure measuring system 1D comprises a pressure measuring device 2D and a pressure measuring chamber 3D, and further comprises an engagement mechanism 4D that engages the two. The pressure measuring device 2D and pressure measuring chamber 3D are the same as the pressure measuring device 2 and pressure measuring chamber 3 described in Embodiment 1, except for the engagement mechanism 4D. Therefore, the following description will focus on the engagement mechanism 4D. Figures 9A and 9B illustrate the orientation of the pressure measuring device 2D and pressure measuring chamber 3D, with the third direction in Figure 1 being the front-rear direction.

[0098] The engagement mechanism 4D consists of an engagement portion 11 provided on the pressure measuring device 2D and an engaged portion 33 provided on the pressure measuring chamber 3D. The engagement portion 11 includes a cylindrical portion 120 protruding from the housing wall 10, two arc-shaped wall portions 121 and 122 erected on the housing wall 10 with the cylindrical portion 120 in between, and two further engaging wall portions 123 and 124 erected on the housing wall 10 with the cylindrical portion 120 in between.

[0099] Of these, the cylindrical portion 120 has a cylindrical shape with a height smaller than its diameter. The two arc-shaped wall portions 121 and 122 are shaped along the same circumference centered on the cylindrical portion 120, are taller than the cylindrical portion 120, and have a circumference with a central angle of approximately 45 to 60 degrees. In Figure 9A, these arc-shaped wall portions 121 and 122 are positioned to the upper right and lower left of the cylindrical portion 120, respectively.

[0100] Furthermore, the two engaging walls 123 and 124 are rectangular plate-shaped, higher than the cylindrical portion 120, and have claw-like projections 123a and 124a at their tips that extend toward each other. In Figure 9A, the engaging walls 123 and 124 are positioned to the right and left of the cylindrical portion 120, respectively. These engaging walls 123 and 124 are flexible, and their tips can be elastically deformed to the left and right relative to their base.

[0101] On the other hand, the engaged portion 33 of the pressure measuring chamber 3D is composed of the bottom wall portion 130 of the first case 35 and the peripheral portion 131 of the second case 36. The bottom wall portion 130 of the first case 35 has a circular flat surface and a constant thickness. The shape and area of ​​the main surface of the bottom wall portion 130 are substantially the same as the shape and area of ​​the end face of the cylindrical portion 120 described above. Furthermore, the peripheral portion 131 of the second case 36 consists of the upper surface of the second circumferential portion 46 (see also Figure 2B of Embodiment 1) of the second case 36 and is a surface parallel to the bottom wall portion 130.

[0102] The pressure measuring device 2D and pressure measuring chamber 3D described above are mounted with the lower part of the pressure measuring chamber 3D facing rearward, and the bottom wall portion 130 of the pressure measuring chamber 3D facing the cylindrical portion 120 of the pressure measuring device 2D. At this time, the two arc-shaped wall portions 121 and 122, similar to the arc-shaped wall portions 63 and 64 of Embodiment 2, contact the circumferential surface 31a of the housing 31 of the pressure measuring chamber 3D to hold the pressure measuring chamber 3D and regulate its circumferential position (orientation).

[0103] Furthermore, the two engaging wall portions 123 and 124 contact the circumferential surface 31a of the housing 31, and the claw portions 123a and 124a engage with the upper surface of the second circumferential portion 46 of the housing 31, that is, with the peripheral edge 131 of the second case 36. This engagement is achieved by snap-in due to the elastic deformation of the engaging wall portions 123 and 124. As the engaging wall portions 123 and 124 engage with the second case 36, the engaged portion 33 engages with the engaging portion 11, and the pressure measuring device 2D and the pressure measuring chamber 3D become engaged.

[0104] In this engaged state, the end face of the cylindrical portion 120 and the bottom face of the bottom wall portion 130 are in surface contact. Therefore, if the pressure measuring device 2D is configured to have a blood sensor 14 inside the housing wall 10 corresponding to the engaged portion 11, the blood sensor 14 can accurately measure the state of the blood in the liquid chamber 30a. For example, if an infrared sensor is used as the blood sensor 14, since the cylindrical portion 120 and the bottom wall portion 130 are in surface contact, the scattering of infrared rays emitted from the blood sensor 14 to the liquid chamber 30a is suppressed, and the measurement accuracy can be improved. Furthermore, as shown in Figure 9B, if the thickness dimension of the bottom wall portion 130 is constant, infrared rays can pass through any position on the bottom wall portion 130 under the same conditions, thus further improving the measurement accuracy.

[0105] (Embodiment 6) The pressure measuring system 1E according to Embodiment 6 will be described with reference to Figures 10A, 10B, and 11. Figure 10A is a perspective view showing the pressure measuring device 2E and pressure measuring chamber 3E in an engaged state, Figure 10B is a plan view of them viewed from above, and Figure 11 is a perspective view of them viewed from the rear (inside the pressure measuring device 2E). This pressure measuring system 1E comprises a pressure measuring device 2E and a pressure measuring chamber 3E, and further comprises an engagement mechanism 4E that engages the two. The engagement mechanism 4E also has an engaging portion 11 and an engaged portion 33.

[0106] The engagement mechanism 4E according to this embodiment has an engagement portion 11 that has a gripping mechanism 140 that grips the pressure measuring chamber 3E and is rotatable. On the other hand, the pressure measuring chamber 3E having the engaged portion 33 only needs to be configured to be gripped by the gripping mechanism 140 of the engagement portion 11, and its specific configuration is not particularly limited. Therefore, here, as the pressure measuring chamber 3E, we will give an example that has substantially the same configuration as the pressure measuring chamber 3C described in Embodiment 4, and omit a detailed explanation. In the pressure measuring chamber 3E, the housing 31 (more specifically, the chamber body 29) constitutes the engaged portion 33.

[0107] The configuration of the engagement portion 11 provided by the pressure measuring device 2E in the engagement mechanism 4E will be described in detail below. The gripping mechanism 140 of the engagement portion 11 has a first gripping body 141 and a second gripping body 142. The first gripping body 141 is fixed to the tip (front end) of a shaft 143 that extends forward from the housing wall 10, and has a base portion 150, a hinge portion 151, a gripping piece 152, and an operating portion 153.

[0108] The first gripping body 141 is fixedly connected to the tip of the shaft 143 at the base 150, and the front surface 150a of the base 150 is a flat surface that stably supports the bottom of the pressure measuring chamber 3E. In addition, a projection 150b is provided on one side of the base 150 (the right side in Figure 10B) that extends forward from the front surface 150a, and the pressure measuring chamber 3E is supported more stably by the front surface 150a and the projection 150b.

[0109] A hinge portion 151 and a gripping piece 152 extend from the other side of the base portion 150 (the left side in Figure 10B). The hinge portion 151 extends diagonally to the left and rear from the base portion 150 and has a wedge shape that tapers towards the tip. The hinge portion 151 also has a concave portion 151a that engages with the second gripping body 142, as shown in Figure 10B. This concave portion 151a forms a groove that extends in the vertical direction in Figure 10B, and the contour of the cross-section perpendicular to the vertical direction is circular.

[0110] The gripping piece 152 is plate-shaped and extends diagonally forward to the left from the base 150. As shown in Figure 10B, it has a claw shape that curves out to the left in a plan view in order to engage with the housing 31 of the pressure measuring chamber 3E. Furthermore, an operating part 153 extends to the left from the outer surface of the curved portion of the gripping piece 152. The operating part 153 is plate-shaped and has a cylindrical finger rest 153a at its tip for gripping with the fingertips during operation.

[0111] The second gripping body 142 has a base 160, a hinge portion 161, a gripping piece 162, and an operating portion 163. The base 160 has a through hole 160a in the front-rear direction, through which the shaft 143 is inserted. The gripping piece 162 extends from one side of the base 160 (the right side in Figure 10B). The gripping piece 162 is plate-shaped and curves forward from the base 160.

[0112] A hinge portion 161 and an operating portion 163 extend from the other side of the base portion 160 (the left side in Figure 10B). The hinge portion 161 extends diagonally forward and to the left from the base portion 160, and its tip is provided with a cylindrical convex portion 161a whose axis is oriented vertically in Figure 10B. This convex portion 161a of the hinge portion 161 is supported by the concave portion 151a of the hinge portion 151 described above. Therefore, in the state shown in Figure 10B, the hinge portion 161 is rotatable relative to the hinge portion 151 around its vertical axis.

[0113] The operating section 163 is plate-shaped and extends to the left from the base 160, then changes direction diagonally backward and extends further. A cylindrical finger rest 163a is formed at the tip of the operating section 163 for gripping the fingertips during operation. The finger rest 153a of the first gripping body 141 and the finger rest 163a of the second gripping body 142 are in approximately the same position in the left-right direction when not in operation, with the finger rest 153a positioned in front of the finger rest 163a.

[0114] The shaft 143 is provided so as to penetrate both the inside and outside of the housing wall 10. Inside the housing wall 10, a cylindrical cylinder 144 is provided coaxially with respect to the shaft 143. The shaft 143 passes through the inside of this cylinder 144, and the rear end 143a of the shaft 143 penetrates the rear wall 144a of the cylinder 144 and protrudes to the outside.

[0115] A rod-shaped pin 145 is provided radially through the rear end 143a of the shaft 143, with both ends of the pin 145 protruding from the circumferential surface at the rear end 143a of the shaft 143. In addition, multiple pin grooves 144c are formed in the rear wall 144a of the cylinder 144, extending radially from the hole 144b through which the shaft 143 passes. The position of the shaft 143 around its axis is determined by the engagement of both ends of the pin 145 with one of these multiple pin grooves 144c.

[0116] Furthermore, the gripping mechanism 140 has a slider 146. The slider 146 is cylindrical, with its rear end housed within the cylinder 144 and its front end 146a protruding forward from the housing wall 10. The aforementioned shaft 143 also protrudes forward and backward through the internal space of the slider 146. The front end 146b of the slider 146 abuts against the rear surface of the base 160 of the second gripping body 142. This slider 146 is biased forward by an elastic member such as a spring provided within the cylinder 144.

[0117] When not being operated by a user, the gripping mechanism 140 is in a closed state with the gripping pieces 152 and 162 close together. When a user operates the gripping mechanism 140 in the closed state, bringing the operating parts 153 and 163 closer to it, it changes from the closed state to the open state. That is, when a user places their fingers on the finger rests 153a and 163a and operates the operating parts 153 and 163 closer together, the hinge part 161 rotates relative to the hinge part 151, and the second gripping body 142 presses the slider 146 backward. The pressed slider 146 retracts into the cylinder 144 against the biasing force of the elastic member, and the second gripping body 142 rotates backward. As a result, the gripping mechanism 140 opens, with the gripping piece 152 moving away from the gripping piece 162.

[0118] Furthermore, in the open state, the gripping mechanism 140 can position the pressure measuring chamber 3E between the gripping pieces 152 and 162, or remove it from between the gripping pieces 152 and 162, and in the closed state, it can support the pressure measuring chamber 3E by sandwiching it between the gripping pieces 152 and 162. When the gripping mechanism 140 supports the pressure measuring chamber 3E, the gripping pieces 152 and 162 of the gripping mechanism 140 become engaging parts 11 and engage with the engaged part 33 formed by the housing 31 of the pressure measuring chamber 3E.

[0119] Furthermore, in this gripping mechanism 140, a shaft 143, on which a first gripping body 141 and a second gripping body 142 are provided at its tip, is biased forward by an elastic member and a slider 146 in a cylinder 144. This biasing force causes a pin 145 provided at the rear end of the shaft 143 to engage with a plurality of pin grooves 144c. Therefore, the user can rotate the shaft 133 by grasping the first gripping body 141 and the second gripping body 142 and rotating it with a force greater than the biasing force, thereby changing the pin grooves 144c into which the pin 145 engages. As a result, the gripping mechanism 140 can rotatably restrict the posture of the pressure measuring chamber 3E.

[0120] (Embodiment 7) The pressure measuring system according to Embodiment 7 is configured such that the pressure measuring device has a pocket provided in the housing wall, and the pressure measuring chamber is housed in this pocket. For example, this pocket opens upward, and the pressure measuring chamber can be moved in and out vertically through this opening. Preferably, a through hole is provided at the bottom of the pocket that penetrates from the inside to the outside, and a notch is formed on the side of the pocket. With such a configuration, if the first port is on one side of the housing and the second port is on the other side of the housing, the pressure measuring chamber can be housed in the pocket such that the first port passes through the through hole via the notch.

[0121] Furthermore, a slit may be provided in the wall of the pocket, extending from the through-hole at the bottom to the edge of the opening at the top. In this case, the tube can be inserted into the pocket through the slit while the tube remains connected to the first port, thereby housing the pressure measuring chamber in the pocket. Such a pocket forms an engaging portion that supports the pressure measuring chamber, preventing it from being displaced downward in the direction of gravity. The shape and dimensions of the pocket, as well as the depth from the opening to the bottom, are not particularly limited, and as an example, it may be configured to accommodate half the volume of the entire pressure measuring chamber.

[0122] In the pressure measuring system according to Embodiment 7 described above, for example, the portion around the through-hole at the bottom of the pocket forms an engaging portion. The portion around the first port passing through the through-hole in the chamber body of the pressure measuring chamber forms an engaged portion that engages with the engaging portion. By engaging these engaging and engaged portions with each other, the pressure measuring chamber is supported by the pocket of the pressure measuring device, and its displacement downward in the direction of gravity is restricted. The configuration of the pressure measuring chamber applied to this embodiment is not particularly limited, but as an example, the pressure measuring chamber 3 according to Embodiment 1 can be applied. In that case, the engaged portion 33 of the pressure measuring chamber 3 can be omitted. Furthermore, as a modification of the pocket, the height of the side surface may be made sufficiently low and convex, and although the pressure measuring chamber is not housed there, the configuration may be such that the pressure measuring chamber does not move outside the bottom. [Industrial applicability]

[0123] This disclosure can be suitably applied to diaphragm-type pressure measuring chambers. [Explanation of symbols]

[0124] 1. Pressure measurement system 2. Pressure measuring device 3. Chamber for pressure measurement 4. Engagement mechanism 11 Engagement part 12 pressure-receiving ports 13. Pressure Sensor 28 connection holes 29 Chamber Body 30 Chamber Space 30a Liquid chamber 30b air chamber 31 Housing 32 diaphragm 33 Engaged part 35. Case 1 36. Case 2 P1 Port 1 P2 2nd Port P3 3rd Port

Claims

1. A diaphragm-type pressure measuring chamber connected to a fluid delivery device having a pressure-receiving port, for measuring the pressure of blood in a blood circuit, The device comprises a housing having a chamber body that forms a chamber space inside, and a flexible diaphragm that divides the chamber space into a liquid chamber and an air chamber, The housing has a first port connected to the chamber body for blood flowing into the liquid chamber, a second port connected to the chamber body for blood flowing out of the liquid chamber, and a third port, one end of which is connected to the chamber body and communicates with the air chamber, and the other end of which is connected to the pressure receiving port via a flexible tube. The housing is provided with an engaged portion that engages with an engaging portion of the pressure measuring device when the third port is connected to the pressure receiving port, and the engagement portion engages with the engaged portion to restrict the downward displacement of the chamber body in the direction of gravity. Chamber for measuring pressure.

2. The engaged portion is configured such that, when engaged with the engaged portion, the liquid chamber is located closer to the pressure measuring device than the air chamber. A pressure measuring chamber according to claim 1.

3. The housing comprises a first case that forms the liquid chamber between itself and the diaphragm, and a second case connected to the first case that forms the air chamber between itself and the diaphragm. The diaphragm has a clamped portion that is sandwiched between the first case and the second case, The third port is connected to the second case, The engaged portion is a protrusion or recess provided on the first case. A pressure measuring chamber according to claim 1.

4. The engaged portion is configured such that, when engaged with the engaged portion, the second port communicates with the upper vertical portion of the liquid chamber. A pressure measuring chamber according to claim 1.

5. The engaged portion is configured to allow the housing to rotate while maintaining the state of being engaged with the engaging portion. A pressure measuring chamber according to claim 1.

6. The engaged portion is configured such that, when engaged with the engaged portion, the liquid chamber is located vertically below the air chamber. A pressure measuring chamber according to claim 1.

7. The connection hole of the flexible tube in the third port is configured to face the pressure-receiving port when the engaged portion is engaged with the engaging portion. A pressure measuring chamber according to claim 1.

8. A diaphragm-type pressure measuring chamber connected to a fluid delivery device having a pressure-receiving port, for measuring the pressure of blood in a blood circuit, The device comprises a housing having a chamber body that forms a chamber space inside, and a flexible diaphragm that divides the chamber space into a first chamber and a second chamber, The housing has a port connected to the chamber body and communicating with the first chamber, and a pressure monitoring port, one end of which is connected to the chamber body and communicating with the second chamber, and the other end of which is connected to the pressure receiving port via a flexible tube. The housing is provided with an engaged portion that engages with an engaging portion of the liquid delivery device when the pressure monitoring port is connected to the pressure receiving port, and the engagement portion engages with the engaged portion to restrict the downward displacement of the chamber body in the direction of gravity. Chamber for measuring pressure.

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