JP6128913B2 - Pressure chamber - Google Patents

Description

  The present invention is incorporated in a liquid circuit such as a blood circuit in which a liquid that is desired to avoid contact with air, such as blood, blood products, or replenishment fluid, and is connected to a pressure sensor that detects the internal pressure of the liquid circuit. Relates to the pressure chamber.

  When extracorporeal blood purification therapy such as continuous slow blood filtration therapy (CRRT) is performed, a blood circuit is formed to remove blood from the patient as a patient, purify the blood with a blood purification device, and return it to the subject There is a need to. As a blood circuit, a type in which a basic configuration is unitized has been used because of ensuring hermeticity and easy handling. For example, the tubes arranged on the upstream side (arterial side) and downstream side (venous side) of a purifier such as a blood filter are combined, and a pressure chamber for detecting the internal pressure of the blood circuit is incorporated into a unit. Is known.

  When the liquid to be transferred is a special liquid such as blood, it is necessary to suppress the occurrence of thrombus as well as sterilization and to avoid contact with air as much as possible. Thus, for example, as a pressure chamber incorporated in a special liquid circuit such as a blood circuit, a pressure chamber of a type that can block contact between blood and air by a diaphragm may be used (see Patent Document 1). In this type of pressure chamber, a blood chamber (liquid chamber) and an air chamber (gas chamber) partitioned by a diaphragm are formed in the container, and the internal pressure of the liquid circuit is transmitted to the gas chamber side by elastic deformation of the diaphragm, The internal pressure is detected by a pressure sensor.

JP 2008-051663 A

  In the case of the conventional pressure chamber, since the liquid chamber and the gas chamber are partitioned by a diaphragm, it is very effective in that the contact between the liquid and the gas can be effectively cut off. It has been found that in negative pressure chambers, negative pressure characteristics can be unstable.

  An object of the present invention is to provide a pressure chamber that can accurately and stably detect the internal pressure of a liquid circuit in which a liquid that is desired to avoid contact with air flows. And

  In the case of a pressure chamber of a type in which a diaphragm is sandwiched between two container members, a person skilled in the art normally manufactures the diaphragm so that it is in a flat state, which is simpler and easier in design. is there. However, the present inventors have intensively studied to achieve the above object. Rather, the negative pressure characteristics of the pressure chamber can be stabilized by arranging the diaphragm so as to be biased toward the gas chamber side, and the liquid circuit The inventors have found that the detection accuracy of the internal pressure can be improved and have arrived at the present invention.

That is, the present invention is a pressure chamber that is incorporated in a liquid circuit in which a liquid that is desired to avoid contact with air flows and that is connected to a pressure sensor that detects the internal pressure of the liquid circuit, and has an inlet and an outlet for the liquid. A liquid chamber container provided to form a liquid chamber in which a liquid flows; a gas chamber container coupled to the liquid chamber container to form a gas chamber communicating with the pressure sensor; and the liquid chamber container and the gas chamber container. And a diaphragm that partitions the liquid chamber and the gas chamber and elastically deforms to transmit the internal pressure of the liquid chamber to the gas chamber, and the liquid chamber container has an inner peripheral edge on the liquid chamber side in a sandwiching portion that sandwiches the diaphragm. The diaphragm is disposed on the inner side surrounded by the inner peripheral edge and is biased to the gas chamber side from the planar virtual boundary surface including the inner peripheral edge, and the sandwiching portion protrudes to the gas chamber container side, And the protrusion provided along the inner periphery The gas chamber container has a groove portion that receives the protrusion and guides the diaphragm toward the gas chamber, and the sandwiching portion is provided outside the protrusion and has the same direction as the virtual boundary surface And the diaphragm is sandwiched by at least the flat surface.

In the present invention, even when the internal pressure of the liquid circuit becomes a negative pressure, the diaphragm arranged biased to the gas chamber side is appropriately elastically deformed and functions normally, and the negative pressure characteristic can be prevented from being lowered. As a result, the negative pressure characteristic in the pressure chamber can be stabilized, and the detection accuracy of the internal pressure of the liquid circuit can be improved. In addition, when the diaphragm is sandwiched between the liquid chamber container and the gas chamber container, the main part of the diaphragm that divides the liquid chamber and the gas chamber within the container is surely secured to the gas chamber side due to the engagement between the protrusion and the groove. This is advantageous for stabilizing the negative pressure characteristic. Further, when the diaphragm is clamped, a force acts in the direction perpendicular to the diaphragm from the air chamber container side on the flat surface of the clamping part. That is, the diaphragm can be clamped without pulling the diaphragm outward, and the liquid chamber container and the air chamber container can be reliably coupled by welding or the like.

  In particular, when the liquid is blood and the liquid circuit is a dialysis circuit, the advantage of the present invention that can prevent the negative pressure characteristic from being lowered while suppressing the occurrence of thrombus is very high.

Further, the protrusion has an inner peripheral surface facing the liquid chamber and a tapered surface on the outer side opposite to the inner peripheral surface, the inner peripheral edge is an end of the inner peripheral surface, and the groove portion is a tapered portion. It is preferable to have a slope having a slope corresponding to the surface. Since the tapered surface and the inclined surface are engaged with each other, it is possible to reduce a load applied to the diaphragm when the diaphragm is sandwiched.

  Further, the diaphragm of the present invention includes a sandwiched portion that is sandwiched between the liquid chamber container and the gas chamber container, a membrane main portion that partitions the liquid chamber and the gas chamber inside the sandwiched portion, and the sandwiched portion. It is preferable to have a latching portion that is bent along the outer edge of the liquid chamber container and latched in contact with the outer periphery of the liquid chamber container. By hooking the latching portion on the outer periphery of the liquid chamber container, positioning when setting the liquid chamber container becomes easy and reliable, and also prevents displacement. As a result, it is difficult for wrinkles or the like to occur in the diaphragm when sandwiched between the gas chamber container and the quality of the pressure chamber can be improved.

  Further, it is preferable that the gas chamber container has a cover portion that projects outward from the sandwiching portion of the liquid chamber container and engages with the outer periphery of the liquid chamber container. Since the cover part of the gas chamber container is engaged with and hooked to the outer periphery of the liquid chamber container, the centering of the gas chamber container with respect to the liquid chamber container is easy and reliable, and the protrusion of the liquid chamber container and the gas chamber container The shift of the corresponding position with the groove can be prevented. In addition, it can also be set as the structure which clamps said latching part between a cover part and the outer periphery of a liquid chamber container, and according to this structure, a latching part can be hold | maintained further reliably.

  Further, the diaphragm of the present invention includes a sandwiched portion sandwiched between the liquid chamber container and the gas chamber container, a membrane main portion that partitions the liquid chamber and the gas chamber inside the sandwiched portion, and the sandwiched portion. It is preferable to have a latching portion that is bent along the outer edge of the gas chamber and is brought into contact with the outer periphery of the gas chamber container. By hooking the latching portion on the outer periphery of the gas chamber container, alignment when setting the diaphragm to the gas chamber container is easy and reliable, and also prevents displacement. As a result, it becomes difficult for wrinkles or the like to occur in the diaphragm when sandwiched between the liquid chamber container and the quality of the pressure chamber can be improved.

  Furthermore, it is preferable that the liquid chamber container has a cover portion that projects outward from the sandwiching portion and engages with the outer periphery of the gas chamber container. Since this cover part is engaged and caught on the outer periphery of the gas chamber container, the centering of the liquid chamber container with respect to the gas chamber container is easy and reliable, and the protrusion of the liquid chamber container and the groove part of the gas chamber container The shift of the corresponding position can be prevented. In addition, it can also be set as the structure which clamps said latching part between the cover part and the outer periphery of a gas chamber container, and according to this structure, a latching part can be hold | maintained further reliably.

  According to the present invention, it is possible to accurately and stably detect the internal pressure of a liquid circuit in which a liquid desired to avoid contact with air flows.

It is a perspective view which shows an example of the blood purification apparatus. It is a figure which shows an example of the blood panel circuit by which an air free pressure chamber is assembled | attached. It is a disassembled perspective view of the air free pressure chamber which concerns on this embodiment. It is a rear view of the air free pressure chamber with which the chamber holder was mounted | worn. It is sectional drawing along the VV line of FIG. It is sectional drawing along the VI-VI line of FIG. It is sectional drawing which expands and shows the flange part of the main body case which clamps the to-be-clamped part of a diaphragm, and the flange receiving part of a cover case. It is a figure which shows typically the flow of the blood in an air free pressure chamber, (a) has shown the flow at the time of seeing an air free pressure chamber from the front, (b) is an air free pressure chamber. It is sectional drawing of this, and shows the case where the pressure in a blood panel circuit fluctuates to positive pressure, (c) is a figure which shows the case where it fluctuates to negative pressure. It is a graph which shows the blood pressure reduction characteristic by the difference in diaphragm arrangement | positioning. It is sectional drawing of the air free pressure chamber which concerns on 2nd Embodiment of this invention.

Hereinafter, a preferred embodiment of the present invention will be described. First, an example of a blood purification apparatus will be introduced with reference to FIG. 1, and a blood panel circuit attached to the blood purification apparatus will be described with reference to FIG. explain.
(Blood purification device and blood panel circuit)

  The blood purification apparatus 1 employs a two-sided system that can handle various treatment modes. A blood system panel circuit is attached to the circuit attachment portion 11 on the front side, and the right side that appears when the right door 12 is opened. A liquid panel circuit is mounted on the circuit mounting portion (not shown). For example, in the apheresis mode, which is a technique for removing a pathogenic substance from a subject by extracorporeal circulation, a blood system panel circuit is mounted on the front circuit mounting section 11 and a plasma system panel circuit is mounted on the right circuit mounting section. Installed. In the ascites mode, the filtration-type panel circuit is mounted on the front side, and the concentration-type panel circuit is mounted on the right side. The liquid flowing in each of these panel circuits is basically a liquid that is desired to avoid contact with air. Therefore, each panel circuit is an example of a liquid circuit.

  Hereinafter, with reference to FIG. 2, a blood panel circuit 2 used in continuous slow blood filtration therapy (CRRT) will be described as an example of a liquid circuit (for example, a dialysis circuit). CRRT is a long and gentle fluid adjustment therapy for the treatment of acute renal failure. In CRRT, a blood circuit (see FIG. 8) taken out from a subject is purified by a blood filter, a replacement circuit is appropriately added to the treated blood Ba, and then a circulation circuit is returned to the subject. There is a need.

  A blood panel circuit (hereinafter referred to as “blood circuit”) 2 includes a line (hereinafter referred to as “arterial line”) 21 through which blood Ba taken out from the subject is sent to the blood filter and a purification process performed by the blood filter. And a downstream line (hereinafter referred to as “venous line”) 22 for returning the blood Ba to the subject.

  The arterial line 21 and the venous line 22 are basically composed of a tube 2a made of vinyl chloride, and the arterial line 21 and the venous line 22 are integrated by an inverted L-shaped panel 2b. In the arterial line 21, air-free pressure chambers (hereinafter referred to as “pressure chambers”) 3 are disposed at two positions sandwiching a portion installed in the blood pump 13 (see FIG. 1). One pressure chamber 3 is connected to the tube 2a on the blood removal side on the subject side, and the other pressure chamber 3 is connected to the tube 2a on the inlet side on the blood filter side.

A blood filter holder 14 and a blood pump 13 are attached to the circuit mounting portion 11 on the front side of the blood purification apparatus 1. The circuit mounting portion 11 is provided with a chamber mounting portion 15 to which the pressure chamber 3 of the blood circuit 2 is mounted. The chamber mounting portion 15 includes a tubular pressure receiving port 16 into which the connection pipe 65 of the pressure chamber 3 is inserted, and a pair of hooks 18 that position and hold the pressure chamber 3. The pressure receiving port 16 communicates with a pressure sensor 1a (see FIG. 8) that detects the internal pressure of the blood circuit 2.
(First embodiment)

  Next, the pressure chamber 3 according to the first embodiment of the present invention will be described. As shown in FIGS. 3 to 6, the pressure chamber 3 divides the blood chamber B and the air chamber A in the container main body 4 and the container main body 4, and the internal pressure of the blood chamber B is changed to the air chamber by elastic deformation. And a diaphragm 7 for transmitting to A.

  The container body 4 includes a body case 5 and a lid case 6 that closes the opening of the body case 5. In the present embodiment, blood Ba is exemplified as a liquid that is desired to avoid contact with air, and the main body case 5 is an example of a liquid chamber container that forms a blood chamber (liquid chamber) B. The lid case 6 is an example of a gas chamber container that forms an air chamber (gas chamber) A that is coupled to the main body case 5 and communicates with the pressure sensor 1a.

  The main body case 5 is a bottomed short cylindrical (cup-shaped) container that is open at one end facing the lid case 6, and a flange portion that holds the diaphragm 7 between the lid case 6 and the upper end on the open side 51 is provided. The peripheral wall 53 of the main body case 5 is provided with a plurality of substantially triangular reinforcing ribs 52 that support the flange portion 51 at equal intervals. The peripheral wall 53 is provided with an inlet port 54 and an outlet port 55 for blood Ba connected to the tube 2a. The inlet port 54 and the outlet port 55 are integrated by an extended portion 56 that protrudes from the flange portion 51, and are reinforced by the extended portion 56.

  The upper surface of the flange portion 51 is an annular sandwiching portion 51a that sandwiches the diaphragm 7 with the lid case 6, and the inner peripheral edge Ea of the sandwiching portion 51a faces the inner space that forms the blood chamber B. The holding portion 51a is provided with an annular protrusion 51b that protrudes toward the lid case 6 and is provided along the inner peripheral edge Ea. The protrusion 51b has an inner peripheral surface 51c facing the blood chamber B and an outer peripheral surface 51d on the opposite side (see FIG. 7). An end of the inner peripheral surface 51c is an inner peripheral edge Ea, and an outer peripheral surface 51d located on the opposite side to the inner peripheral edge Ea is a tapered surface having a predetermined gradient. Further, the sandwiching portion 51a extends outside the outer peripheral surface (tapered surface) 51d of the protrusion 51b along the same direction as the virtual boundary surface F including the inner peripheral edge Ea, that is, along a plane substantially parallel to the boundary surface F. It has an existing flat surface (flat surface) 51f.

  As shown in FIGS. 3 and 7, the diaphragm 7 is made of a film that can be elastically deformed in conjunction with changes in the internal pressure of the blood circuit 2. The diaphragm 7 has a petri dish shape, and includes a substantially circular membrane body 71 that follows the outer shape of the flange portion 51 of the body case 5, and a latching piece (a latching portion) 72 that bends along the outer edge of the membrane body 71. ing. The membrane main body 71 includes a substantially annular sandwiched portion 71 a that is an area overlapping the flange portion 51, and a membrane main portion 71 b that is inside the sandwiched portion 71 a and blocks the opening of the body case 5. The sandwiched portion 71a is a portion that is sandwiched between the main body case 5 and the lid case 6, and the membrane main portion 71b is a portion that partitions the blood chamber B and the air chamber A inside the case.

  The latching piece 72 is latched by coming into contact with the outer periphery of the flange portion 51, that is, the outer periphery of the main body case 5. When the diaphragm 7 is set on the main body case 5, the centering position can be easily adjusted by hooking the retaining piece 72 on the outer periphery of the flange portion 51, and it is also difficult to be displaced when sandwiched and fixed by the lid case 6. The high-quality pressure chamber 3 can be manufactured easily and stably. In addition, the latching piece 72 is not necessarily provided over the outer periphery perimeter of the to-be-clamped part 71a, and one part is excised. The cut portion is an avoiding portion 71c (see FIG. 3) that escapes the extending portion 56 that connects the inlet port 54 and the outlet port 55 of the main body case 5, and the avoiding portion 71c is fitted into the extending portion 56. By mounting, the rotational displacement of the diaphragm 7 in the circumferential direction is also suppressed.

  As shown in FIGS. 3, 5, and 6, the lid case 6 sandwiches the diaphragm 7, and forms a cover 61 that forms the air chamber A, and a cover that is provided along the outer edge of the lid 61. Part 62. The cover part 62 projects to the outside of the sandwiching part 51 a of the main body case 5 while being coupled to the main body case 5, and engages with the outer periphery of the main body case 5. More specifically, the cover portion 62 protrudes toward the main body case 5 and sandwiches the retaining piece 72 of the diaphragm 7 between the outer periphery of the flange portion 51.

  On the back surface side (inner surface side) of the lid portion 61, an annular flange receiving portion 61 a that sandwiches the sandwiched portion 71 a of the diaphragm 7 with the flange portion 51 of the main body case 5 is provided. There is a dent in the region near the center surrounded by the flange receiving portion 61a, and the air chamber A is formed by this dent.

  The flange receiving portion 61a is a holding portion on the side of the lid case (air chamber forming container) 6 that holds the diaphragm 7 between the holding portion 51a of the main body case 5, and the inner peripheral edge Eb of the flange receiving portion 61a (see FIG. 7). ) Faces the inner space (dent) forming the air chamber A. The flange receiving portion 61a is provided with an annular notch (groove portion) 61b along the inner peripheral edge Eb. The notch 61b has a shape corresponding to the protrusion 51b of the main body case 5, and has a slope 61c having a gradient corresponding to the tapered outer peripheral surface 51d of the protrusion 51b.

  The notch 61b receives the protrusion 51b of the main body case 5 with the sandwiched portion 71a of the diaphragm 7 sandwiched therebetween, and guides the membrane main portion 71b of the diaphragm 7 toward the air chamber A side. That is, when the protruding portion 51b is fitted into the notch 61b with the sandwiched portion 71a being sandwiched, the sandwiched portion 71a is brought into contact with the projecting portion 51b in the vicinity of the inner peripheral edge Ea (or the inner peripheral edge Eb) facing the blood chamber B. It is pushed and bends along the notch 61b. As a result, the inner membrane main portion 71b is disposed closer to the lid portion 61 than the virtual flat boundary surface F including the inner peripheral edge Ea, that is, to the air chamber A side.

  A connection pipe 65 to be inserted into the pressure receiving port 16 of the blood purification device 1 is provided on the front surface side (outer surface side) of the lid portion 61. The connecting pipe 65 communicates with a recess on the back side that becomes the air chamber A. An O-ring 63 that is a seal member is fitted into the connection pipe 65, and an annular rib 64 that houses the O-ring 63 is provided around the connection pipe 65. When the connecting pipe 65 is inserted into the pressure receiving port 16, the O-ring 63 is pressed by the tip of the pressure receiving port 16 to close the gap and ensure airtightness.

  The lid 61 is provided with a plurality of longitudinal reinforcing ribs 6a extending radially from the annular rib 64, and further, a plurality of circular reinforcements concentric with the annular rib 64 so as to intersect the longitudinal reinforcing rib 6a. Ribs 6b are provided.

  The body case 5 and the lid case 6 are overlapped with the diaphragm 7 sandwiched therebetween, and the portion where the flange portion 51 of the body case 5, the sandwiched portion 71 a of the diaphragm 7, and the flange receiving portion 61 a of the lid case 6 overlap. They are combined and integrated by high frequency welding and other joining methods. In this state, the diaphragm 7 partitions the inside of the container body 4 composed of the body case 5 and the lid case 6 into a blood chamber B on the body case 5 side and an air chamber A on the lid case 6 side. Complete.

  The pressure chamber 3 is assembled to the chamber holder 8 and attached to the chamber attachment portion 15 of the blood purification apparatus 1 via the chamber holder 8. The chamber holder 8 is provided on a cylindrical hold case 81 that surrounds the pressure chamber 3, a claw portion 82 (see FIG. 5) that holds the pressure chamber 3 in a predetermined position in the hold case 81, and an outer periphery of the hold case 81. And a pair of engaging pieces 83 that engage with the hooks 18 of the chamber mounting portion 15.

  The pressure chamber 3 assembled in the blood circuit 2 is set so that the connecting pipe 65 is inserted into the pressure receiving port 16 of the chamber mounting portion 15 after being fitted into the chamber holder 8. Further, the pair of engaging pieces 83 of the chamber holder 8 are rotated and hooked on the pair of hooks 18 of the chamber mounting portion 15 to be mounted at predetermined positions.

  In the pressure chamber 3 according to the present embodiment, the diaphragm 7 is placed in the air chamber A under standard conditions where the internal pressures of the blood chamber B and the air chamber A are the same, for example, under atmospheric pressure conditions before being incorporated into the blood circuit 2. It is biased to the side. As a result, even if the internal pressure of the blood circuit 2 becomes negative pressure, the diaphragm 7 arranged biased toward the air chamber A side is appropriately elastically deformed and functions normally, and the negative pressure characteristic can be prevented from deteriorating. Therefore, according to the pressure chamber 3, the negative pressure characteristic can be stabilized and the detection accuracy of the internal pressure of the blood circuit 2 can be improved. This operation and effect will be described in more detail with reference to FIG. 8 and FIG.

  As described above, the sandwiching part 51a of the main body case 5 according to the present embodiment has the inner peripheral edge Ea on the blood chamber B side, and the diaphragm 7 is the inner membrane main part 71b surrounded by the inner peripheral edge Ea. It is arranged so as to be biased toward the air chamber A with respect to the virtual boundary surface F including the peripheral edge Ea. On the other hand, in the pressure chamber according to the comparative example, the main part of the diaphragm is flat and aligned on the boundary surface, and is not biased toward the air chamber A side.

  The pressure chamber 3 according to this embodiment is attached to the blood removal side of the arterial line 21 of the blood circuit 2, and a liquid (for convenience, referred to as “blood Ba”) is applied while applying a predetermined internal pressure (horizontal axis in FIG. 9). A test operation was conducted through the circuit 2, and the internal pressure of the blood circuit 2 was measured with the pressure sensor 1 a through the pressure chamber 3 (the vertical axis in FIG. 9).

  The blood Ba flowing through the blood circuit 2 flows in from the inlet port 54 of the pressure chamber 3 and flows out from the outlet port 55 (see FIG. 8A). In this state, when the internal pressure (blood pressure removal) of the blood circuit 2 swings more to the positive pressure side than the standard condition, the diaphragm 7 bends in the direction in which the volume of the air chamber A decreases, as shown in FIG. On the other hand, when the internal pressure of the blood circuit 2 swings to the negative pressure side, the diaphragm 7 swells in the direction in which the volume of the air chamber A increases as shown in FIG.

  About said test, it experimented in the way of raising and lowering internal pressure, and returning, and the internal pressure (de-blood pressure) measured by the pressure sensor 1a was plotted in FIG. Further, the same test was performed on the pressure chamber according to the comparative example, and the internal pressure (blood pressure removal) measured by the pressure sensor 1a was plotted in FIG.

  In FIG. 9, with respect to the pressure (horizontal axis) applied to the fluid flowing in the blood circuit 2, the upper limit allowable value of the measured value actually measured by the pressure sensor 1a is indicated by a one-dot chain line, and the lower limit allowable value is indicated by a two-dot chain line. Is shown. As shown in FIG. 9, in the positive pressure state, both the present embodiment and the comparative example are within the range between the upper limit allowable value and the lower limit allowable value, and stable measurement is possible. ing.

  On the other hand, in the negative pressure state of −300 mmHg or less, the pressure chamber according to the comparative example exceeds the upper limit allowable value, and a decrease in the negative pressure characteristic can be read. In particular, in this experiment, the hysteresis of the diaphragm is observed by looking at the going and returning accompanying the rise and fall of the internal pressure, but in the pressure chamber according to the comparative example, the deviation between the going and the returning is large, and the hysteresis is large. On the other hand, in the pressure chamber 3 according to the present embodiment, even within the negative pressure state, it is within the range between the upper limit allowable value and the lower limit allowable value, and the hysteresis is small, resulting in stable measurement. It is possible to prevent the negative pressure characteristics from being deteriorated.

  That is, in the pressure chamber 3 according to the present embodiment, even when the internal pressure of the blood circuit 2 becomes negative pressure, the diaphragm 7 that is biased to the air chamber A side is appropriately elastically deformed and functions normally, and the negative pressure It can be inferred that the deterioration of characteristics can be prevented. As a result, according to the pressure chamber 3 according to the present embodiment, the negative pressure characteristic can be stabilized and the detection accuracy of the internal pressure of the blood circuit 2 can be improved.

  In particular, in this embodiment, the pressure chamber 3 is incorporated in a blood circuit 2 which is a kind of dialysis circuit, and blood Ba is assumed as a liquid flowing in the circuit. And according to this pressure chamber 3, since the blood chamber B and the air chamber A are completely interrupted | blocked by the partition wall 7, it is advantageous at the point which can suppress the generation | occurrence | production of a thrombus effectively and can prevent the fall of a negative pressure characteristic. Sex is very high.

  As an aspect in which the membrane main portion 71b of the diaphragm 7 is arranged so as to be biased toward the air chamber A with respect to the virtual boundary surface F including the inner peripheral edge Ea, for example, the membrane main portion 71b itself of the diaphragm 7 is curved in advance. It is also conceivable to form a shape that swells to the air chamber A side. However, in this embodiment, the diaphragm 7 is forcibly bent by providing the protrusion 51b on the main body case 5 side and the notch 61b on the lid case 6 side. As a result, the membrane main portion 71b can be surely biased toward the air chamber A due to the engagement between the protruding portion 51b and the notch 61b, which is advantageous in stabilizing the negative pressure characteristics.

  Further, the outer peripheral surface 51d of the annular protrusion 51a is a tapered surface, and the notch 61a has a slope 61c corresponding to the outer peripheral surface 51d. That is, since the outer peripheral surface 51d and the inclined surface 61c are engaged, the load applied to the diaphragm 7 when the diaphragm 7 is sandwiched can be reduced.

  Moreover, the clamping part 51a has the flat surface 51f extended along the same direction as the virtual interface F outside the outer peripheral surface (taper surface) 51d of the projection part 51b. When the diaphragm 7 is sandwiched, a force acts in the direction perpendicular to the diaphragm 7 from the lid case 6 side on the flat surface 51f of the sandwiching portion 51a. That is, the diaphragm 7 can be clamped without pulling the diaphragm 7 outward, and the main body case 5 and the lid case 6 can be reliably coupled by welding or the like. Furthermore, the inner surface of the diaphragm 7 can be forcibly biased to the gas chamber A side by the outer peripheral surface 51d of the projection 51b disposed on the inner side of the flat surface 51f.

  Further, the diaphragm 7 according to the present embodiment has a latching portion 72 that is bent along the outer edge of the sandwiched portion 71 and is latched by contacting the outer periphery of the main body case 5. When the diaphragm 7 is set on the main body case 5, the centering position can be easily and surely secured by hooking the latching piece 72 on the outer periphery of the lid case 6. This makes it difficult to cause misalignment, and it is difficult for wrinkles or the like to be generated on the diaphragm 7, so that the high-quality pressure chamber 3 can be manufactured easily and stably.

Further, the lid case 6 has a cover portion 62 that projects outward from the sandwiching portion 51 a of the main body case 5 and engages with the outer periphery of the main body case 5. Since the cover portion 62 is engaged with and caught by the outer periphery of the main body case 5, the centering of the lid case 6 with respect to the main body case 5 is easy and reliable, and the protrusion 51 b of the main body case 5 and the cover case 6 are cut off. The shift of the corresponding position with the notch (groove portion) 61b can be prevented. In the present embodiment, the latching piece 72 of the diaphragm 7 is sandwiched between the cover part 62 and the outer periphery of the main body case 5, and the latching piece 72 can be reliably held by the cover part 62.
(Second Embodiment)

  Next, a pressure chamber 3A according to a second embodiment of the present invention will be described with reference to FIG. The pressure chamber 3A according to the second embodiment includes the same members and structures as the pressure chamber 3 according to the first embodiment. Therefore, in the following description, the same members and structures are denoted by the same reference numerals as those of the pressure chamber 3 according to the first embodiment, detailed description thereof is omitted, and differences will be mainly described.

  As shown in FIG. 10, the pressure chamber 3A partitions the container body 4A, the blood chamber B in which the blood 8a flows, and the air chamber A within the container body 4A, and reduces the internal pressure of the blood chamber B by elastic deformation. And a diaphragm 7A for transmitting to the air chamber A. Further, the container main body 4A includes a main body case (liquid chamber side container) 5A and a lid case (gas chamber side container) 6A that closes the opening of the main body case 5A.

  The diaphragm 7 </ b> A includes a membrane body 71 and a latching piece (a latching portion) 73 that bends along the outer edge of the sandwiched portion 71 a of the membrane body 71. The latching piece 73 is brought into contact with the outer periphery of the lid case 6A and latched. When the diaphragm 7A is set on the lid case 6A, the centering position can be easily adjusted by hooking the latching piece 73 on the outer periphery of the lid case 6A. As a result, wrinkles and the like are hardly generated in the diaphragm 7A, and a high-quality pressure chamber 3A can be manufactured easily and stably.

  The main body case 5 </ b> A includes a flange portion 51 that sandwiches the diaphragm 7 </ b> A, and a cover portion 57 provided along the outer edge of the flange portion 51. The cover portion 57 projects outward from the sandwiching portion 51a and engages with the outer periphery of the lid case 6A. More specifically, the cover portion 57 protrudes toward the lid case 6A and sandwiches the retaining piece 73 of the diaphragm 7A between the cover case 57 and the outer periphery of the lid case 6A.

  Since the cover portion 57 is engaged with and hooked on the outer periphery of the lid case 6A, the center case 5A can be easily centered with respect to the lid case 6A, and the projection 51b of the body case 5A and the notch in the lid case 6A are cut out. The shift of the corresponding position with 61b can be prevented. Furthermore, in this embodiment, the latching piece 73 is pinched | interposed between the cover part 57 and the outer periphery of the cover case 6A, and the latching piece 73 can be hold | maintained reliably.

  Similar to the pressure chamber 3 according to the first embodiment, the pressure chamber 3A according to the present embodiment also has the same internal pressure in the blood chamber B and the air chamber A under the same conditions, for example, before being incorporated into the blood circuit 2. Under atmospheric pressure conditions, the diaphragm 7A is arranged biased toward the air chamber A. As a result, even when the internal pressure of the blood circuit 2 becomes a negative pressure, the diaphragm 7A arranged to be biased toward the air chamber A is appropriately elastically deformed and functions normally, and the negative pressure characteristic can be prevented from being deteriorated. Therefore, according to the pressure chamber 3A, the negative pressure characteristic can be stabilized, and the detection accuracy of the internal pressure of the blood circuit 2 can be improved.

  DESCRIPTION OF SYMBOLS 1 ... Blood purification apparatus, 1a ... Pressure sensor, 2 ... Blood circuit (liquid circuit), 3, 3A ... Pressure chamber, 5, 5A ... Main body case (liquid chamber container), 51a ... Nipping part, 51b ... Projection part, 51d ... outer peripheral surface (tapered surface) of projection, 51f ... flat surface (flat surface), 54 ... inlet port (liquid inlet), 55 ... outlet port (liquid outlet), 57 ... cover part of main body case, 6, 6A ... lid case (gas chamber container), 61b ... notch (groove), 61c ... slope of the notch, 62 ... cover part of the lid case, 7, 7A ... diaphragm, 71a ... sandwiched part, 71b ... main part of membrane , 72, 73 ... latching part, A ... air chamber (gas chamber), B ... blood chamber (liquid chamber), Ba ... blood (liquid that is desired to avoid contact with air), Ea ... inner peripheral edge, F ... boundary surface.

Claims (7)

A pressure chamber incorporated in a liquid circuit in which a liquid desired to avoid contact with air flows and connected to a pressure sensor for detecting an internal pressure of the liquid circuit;
A liquid chamber container provided with an inlet and an outlet for the liquid, and forming a liquid chamber through which the liquid flows;
A gas chamber container coupled to the liquid chamber container and forming a gas chamber communicating with the pressure sensor;
A diaphragm that is sandwiched between the liquid chamber container and the gas chamber container, partitions the liquid chamber and the gas chamber, and elastically deforms to transmit the internal pressure of the liquid chamber to the gas chamber;
The liquid chamber container has an inner peripheral edge on the liquid chamber side in a sandwiching portion that sandwiches the diaphragm,
The diaphragm is arranged on the inner side surrounded by the inner peripheral edge and is more biased toward the gas chamber than a planar virtual boundary surface including the inner peripheral edge,
The sandwiching portion has a protrusion protruding toward the gas chamber container and provided along the inner peripheral edge,
The gas chamber container has a groove portion that receives the protrusion and guides the diaphragm toward the gas chamber side,
The sandwiching portion has a flat surface that is provided on the outer side of the protruding portion and extends along the same direction as the virtual boundary surface,
The diaphragm is a pressure chamber sandwiched at least by the flat surface .   2. The pressure chamber according to claim 1, wherein the liquid is blood, and the liquid circuit is a dialysis circuit. The protrusions and the inner circumferential surface facing the liquid chamber has a tapered surface on the outside on the opposite side against the inner peripheral surface,
The inner peripheral edge is an end of the inner peripheral surface,
The pressure chamber according to claim 2, wherein the groove has a slope having a slope corresponding to the tapered surface. The diaphragm includes: a sandwiched portion that is sandwiched between the liquid chamber container and the gas chamber container; a main membrane portion that partitions the liquid chamber and the gas chamber inside the sandwiched portion; The pressure chamber according to any one of claims 1 to 3 , further comprising: a hook portion that is bent along an outer edge of the holding portion and is hooked in contact with an outer periphery of the liquid chamber container. . The said gas chamber container has a cover part projected on the outer side rather than the said clamping part of the said liquid chamber container, and engaging with the outer periphery of the said liquid chamber container, The any one of Claims 1-4 characterized by the above-mentioned. The pressure chamber as described. The diaphragm includes: a sandwiched portion that is sandwiched between the liquid chamber container and the gas chamber container; a main membrane portion that partitions the liquid chamber and the gas chamber inside the sandwiched portion; The pressure chamber according to any one of claims 1 to 3 , further comprising: a hook portion that is bent along an outer edge of the sandwiching portion and is hooked in contact with an outer periphery of the gas chamber container. . The pressure according to any one of claims 1 to 3 , wherein the liquid chamber container has a cover portion that projects outward from the sandwiching portion and engages with an outer periphery of the gas chamber container. Chamber.

Images