JP7149828B2 - PRESSURE STRUCTURE FOR SEAL MEMBER AND BLOOD PURIFICATION DEVICE - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sealing member pressing structure, a blood purification device, and a cap.

As a conventional technique, there is known a pressure pod used for detecting the pressure of blood in a blood circuit in which the blood of a patient collected in dialysis treatment (blood purification treatment) is extracorporeally circulated and returned to the body (for example, See Patent Document 1.).

The inside of the pressure pod is divided into a passing fluid side and a gas side by a diaphragm, and a pressure sensor is connected to the gas side. The pressure sensor detects the pressure caused by the movement of the diaphragm due to the pressure of the passing fluid, blood. The pressure of blood in the blood circuit can be detected based on the pressure detected by the pressure sensor.

Japanese Patent Publication No. 2017-504389

Such conventional pressure pods are discarded after one use because blood circulates inside them. For example, when a conventional pressure pod is connected to a pressure sensor via a sealing member, the sealing member must be replaced in a predetermined cycle because the pressure pod is connected and disconnected. If the workability of replacing the seal member is poor, the seal member may be damaged by a tool, or the time required for the work may increase.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a structure for holding a seal member, a blood purification apparatus, and a cap that are easy to maintain.

In order to solve the above-mentioned problems, a sealing member pressing structure according to the first aspect of the present invention includes a fitting member having an insertion opening and a first fitting portion provided on a side surface of the insertion opening;
a seal member disposed in the insertion opening of the fitting member;
When a first force acting on the sealing member attached to the insertion opening and directed outwardly from the insertion opening acts on the sealing member, a second force received from the sealing member on which the first force acts causes the second force to move the sealing member. a cap having a second fitting portion that fits with the first fitting portion;
Prepare.

In the invention according to claim 2, the cap has a sloped surface that converts the direction of the first force to the direction of the second force at a portion that contacts the seal member.
A pressing structure for a seal member according to claim 1 .

According to a third aspect of the present invention, the first fitting portion includes a first protrusion protruding from the side surface of the insertion opening and a first recess having the side surface concavely recessed. having a shape lined up in order from the upstream side in the insertion direction of the opening,
The second fitting portion includes a second concave portion that fits with the first convex portion, and a second concave portion that increases toward the downstream side in the insertion direction of the insertion opening in the fitting with the first concave portion. having 2 protrusions,
A pressing structure for a seal member according to claim 1 or 2.

In the invention according to claim 4, the first fitting portion is formed in an S shape by the first convex portion and the first concave portion,
The second fitting portion has an S shape formed by the second concave portion and the second convex portion,
A pressing structure for a sealing member according to claim 3 .

In the invention according to claim 5, in a cross section cut perpendicular to the edge of the insertion opening,
A first line formed by a reference line based on the upper surface of the fitting member and a straight line extending the outline of the slope of the cap that converts the direction of the first force to the direction of the second force. The angle θ ₁ and the second angle θ ₂ formed by the reference line and the straight line contacting the inflection points of the first convex portion and the first concave portion forming the S shape are
satisfying 30° ≤ θ ₁ ≤ 60° and satisfying θ ₁ ≤ θ ₂ ≤ 90°;
A pressing structure for a seal member according to claim 3 or 4.

In the invention according to claim 6, in a cross section cut perpendicular to the edge of the insertion opening,
a second angle θ ₂ formed between a reference line based on the upper surface of the fitting member and a straight line contacting an inflection point of the first protrusion and the first recess forming an S shape;
A _third angle θ3 between the reference line and a straight line that touches the inflection points of the second concave portion and the second convex portion that form an S shape is
satisfying θ ₂ ≤ θ ₃ ≤ 90°,
A pressing structure for a sealing member according to any one of claims 3 to 5.

According to a seventh aspect of the invention, the fitting member comprises a hollow housing, a diaphragm that divides the inside of the housing into a first space and a second space, and pressure of fluid flowing into the first space. A joint connected to the output port of a chamber having an output port for outputting the gas in the second space as the diaphragm deforms,
The seal member is sandwiched between the side surface of the output port and the side surface of the joint, and moves while rotating when connecting or disconnecting the chamber and the joint.
A pressing structure for a seal member according to any one of claims 1 to 6.

A blood purification apparatus according to claim 8 has the pressing structure according to any one of claims 1 to 7,
Purify human blood.

In the cap according to the ninth aspect of the invention, when the seal member arranged in the insertion opening of the fitting member to be fitted receives the first force in the direction of going out from the insertion opening, the first a second fitting portion that fits with the first fitting portion provided on the fitting member by a second force received from the seal member on which the force of (1) acts.

According to the inventions of Claims 1, 8 and 9, it is possible to improve workability in exchanging the seal member during maintenance, and to suppress damage to the seal surface during the work.

According to the second aspect of the invention, it is possible to prevent the sealing member from slipping out of the insertion opening.

According to the third aspect of the invention, it is possible to prevent the seal member from slipping out of the insertion opening and to facilitate removal of the cap.

According to the invention of claim 4, the removal of the cap is further facilitated.

According to the fifth aspect of the invention, unintended detachment of the cap is suppressed.

According to the sixth aspect of the invention, removal of the cap is facilitated.

According to the invention of claim 7, the durability of the sealing member can be improved.

FIG. 1(a) is a schematic diagram showing an example of a blood purification apparatus employing a structure for pressing a sealing member according to the first embodiment, and FIG. 1(b) is an example of the configuration of the blood purification apparatus. It is a schematic diagram showing. FIG. 2(a) is a perspective view showing an example of a chamber to which a connecting portion according to the first embodiment is connected, and FIG. 2(b) is a schematic diagram showing an example of a pressing structure for a sealing member. be. FIG. 3(a) is a cross-sectional view showing an example of a cross-section of a chamber according to the first embodiment, and FIG. 3(b) is a cross-sectional view showing an example of a connecting portion and an O-ring. FIG. 4(a) is a cross-sectional view for explaining an example of the position of the O-ring when inserting the chamber of the connection structure according to the first embodiment, and FIG. FIG. 5 is a cross-sectional view for explaining an example of the position of the O-ring at the time; FIG. 5(a) is a sectional view for explaining an example of the cap according to the first embodiment, and FIG. 5(b) is an enlarged sectional view for explaining an example of the cap. be. FIG. 6A is an example of a top view of the cap according to the first embodiment, and FIG. 6B is an example of a top view of the cap according to the modification. FIG. 7 is a schematic diagram for explaining an example of O-ring replacement according to the first embodiment. FIG. 8(a) is a schematic diagram for explaining an example of the compression rate of the O-ring according to the first embodiment, and FIG. 8(b) shows a region that is damaged when the O-ring does not rotate. FIG. 8C is a schematic diagram for explaining an example, and FIG. 8C is a schematic diagram for explaining an example of a region that receives damage when the O-ring rotates. 9(a) to 9(d) are schematic diagrams showing an example of connection between the chamber and the connection part in the connection structure according to the first embodiment. 10(a) to 10(c) are cross-sectional views showing an example of connection between the chamber and the connection part in the connection structure according to the first embodiment. FIG. 11(a) is a schematic diagram showing an example of the cap according to the second embodiment, FIG. 11(b) is an enlarged view of an example of the cross section of the cap, and FIG. It is a schematic diagram showing an example of the 1st fitting part and the 2nd fitting part concerning a 3rd embodiment. FIG. 12 is a schematic diagram showing an example configuration of a blood purification apparatus according to a fourth embodiment. FIG. 13(a) is a perspective view showing an example of a connection structure according to a fifth embodiment, FIG. 13(b) is a cross-sectional view showing an example of a cap, and FIG. FIG. 3 is a side view showing an example of a joint; FIG. 14(a) is a cross-sectional view showing an example of a joint to which a cap is attached according to the fifth embodiment, and FIG. 14(b) is a cross-sectional view showing an example of connecting a chamber to a connecting portion. be.

[First embodiment]
(Outline of blood purification device 9)
FIG. 1(a) is a schematic diagram showing an example of a blood purification apparatus employing a structure for pressing a sealing member according to the first embodiment, and FIG. 1(b) is an example of the configuration of the blood purification apparatus. It is a schematic diagram showing. FIG. 2(a) is a perspective view showing an example of a chamber to which a connecting portion according to the first embodiment is connected, and FIG. 2(b) is a schematic diagram showing an example of a pressing structure for a sealing member. be. FIG. 3(a) is a cross-sectional view showing an example of a cross-section of a chamber according to the first embodiment, and FIG. 3(b) is a cross-sectional view showing an example of a connecting portion and an O-ring. FIG. 4(a) is a cross-sectional view for explaining an example of the position of the O-ring when inserting the chamber of the connection structure according to the first embodiment, and FIG. FIG. 5 is a cross-sectional view for explaining an example of the position of the O-ring at the time; Note that in each drawing according to the embodiments described below, the ratio between figures may differ from the actual ratio. "A to B" indicating a numerical range shall be used in the sense of A or more and B or less.

The blood purification device 9 shown in FIG. 1(a) is for performing dialysis treatment. As shown in FIGS. 1(a) and 1(b), the blood purification apparatus 9 includes, for example, a pressure detection unit 10, an arterial blood circuit 11, a venous blood circuit 12, a dialyzer 13, and a dialysate. It has an inlet line 14 , a dialysate outlet line 15 and a dual pump 16 . Among them, the pressure detection unit 10 , the dialysate introduction line 14 , the dialysate discharge line 15 , and the dual pump 16 are configured as a main body 90 . The arterial blood circuit 11 , the venous blood circuit 12 , and the dialyzer 13 are detachably attached to the body 90 .

The arterial blood circuit 11 includes an arterial puncture needle 110 that is punctured into the patient's artery, a connector 111 to which the arterial puncture needle 110 is connected, a clamp 112 that controls the blood flow by opening and closing a valve, and an ironing type. The blood pump 113 which is a pump, and the pressure detection part 10 connected to the arterial blood circuit 11 are provided, and are roughly comprised. This arterial blood circuit 11 is connected to a blood introduction port 13 a of a dialyzer 13 .

The venous blood circuit 12 includes a venous puncture needle 120 to be punctured into a patient's vein, a connector 121 to which the venous puncture needle 120 is connected, and a blood discriminating unit for discriminating whether the fluid flowing through the blood circuit is blood. 122, a clamp 123 that controls the flow of blood by opening and closing a valve, an air bubble detector 124 that detects air bubbles mixed in the fluid flowing through the blood circuit, a vein chamber 125 that separates air bubbles mixed in the fluid, and a vein. and a pressure detection unit 10 connected to the side blood circuit 12 . The venous blood circuit 12 is connected to the blood outlet 13b of the dialyzer 13. As shown in FIG.

When the blood pump 113 is activated in a state in which the arterial puncture needle 110 and the venous puncture needle 120 are punctured, the patient's blood passes through the arterial blood circuit 11 and reaches the dialyzer 13, after which the dialyzer 13 purifies the blood. is performed and returns to the patient's body through the venous blood circuit 12 .

The dialyzer 13 has a blood inlet 13a, a blood outlet 13b, a dialysate inlet 13c, and a dialysate outlet 13d. The dialysate inlet 13c and the dialysate outlet 13d are connected to the dialysate inlet line 14 and the dialysate discharge line 15 extending from the main body 90 of the blood purification device 9, respectively.

The dialyzer 13 has a plurality of hollow fibers and is configured to purify blood with the hollow fibers. Further, the dialyzer 13 is formed with a blood channel connecting the blood inlet 13a and the blood outlet 13b via a blood purification membrane, and a dialysate channel connecting the dialysate inlet 13c and the dialysate outlet 13d. there is The hollow fibers that make up the blood purification membrane have minute holes penetrating the outer and inner peripheral surfaces to form a hollow fiber membrane. Impurities in the blood are dialyzed through the hollow fiber membrane. Penetrates into the liquid.

The dual pump 16 is arranged in the main body 90 of the blood purification device 9 across the dialysate introduction line 14 and the dialysate discharge line 15 . A water removal pump 17 is connected to the dialysate discharge line 15 so as to bypass the double pump 16 . This water removal pump 17 is provided to remove water from the patient's blood flowing through the dialyzer 13 .

One end of the dialysate introduction line 14 is connected to the dialyzer 13, and the other end is connected to concentration adjusting means for adjusting the dialysate to a predetermined concentration. The concentration adjusting means is arranged in the blood purification device 9 or a dialysate supply device that supplies dialysate to the blood purification device. One end of the dialysate drain line 15 is connected to the dialyzer 13, and the other end is connected to the drain means. After reaching the dialyzer 13 through the dialysate introduction line 14 from the dialysate supply device, the dialysate is sent to the drainage means through the dialysate discharge line 15 .

A pressure detector 10 is connected to the arterial blood circuit 11 and the venous blood circuit 12 . The pressure detector 10 is configured to detect the pressure _PR of blood flowing through the arterial blood circuit 11 and the venous blood circuit 12 . The pressure detection unit 10 is configured by connecting a pressure sensor 10a arranged in a panel 101 of the main body 90 of the blood purification device 9 and the connection unit 3 by a tube 10b.

The connecting portion 3 has a pressing structure 1 for a sealing member. Specifically, as shown in FIGS. 2(a) to 3(b), the sealing member pressing structure 1 has an insertion opening 301, and a first fitting portion 307 is formed on a side surface 302 of the insertion opening 301. , a sealing member disposed in the insertion opening 301 of the member, and a first a cap 4 having a second fitting portion 48 that increases the contact area formed by fitting with the first fitting portion 307 by a second force received from the seal member on which the force of configured as follows.

A member of this embodiment is a joint 30 . This joint 30 is connected with the output port 27 of the chamber 2 . As shown in FIG. 3( a ), the chamber 2 includes a hollow housing 20 , a diaphragm 25 dividing the inside of the housing 20 into a first space 23 and a second space 24 , and fluid flowing into the first space 23 . An output port 27 is provided for outputting the gas K in the second space 24 as the diaphragm 25 is deformed by the pressure of (blood R). Although the fluid in this embodiment is blood, it is not limited to this, and other fluids such as dialysate may be used. The pressure detection unit 10 is configured to indirectly detect the pressure P _R of the blood R by detecting the pressure P _K of the gas K based on the deformation of the diaphragm 25 due to the pressure P _R of the blood R. .

The sealing member of the present embodiment is the O-ring 5 having a ring shape, but is not limited to this, and has a circular cross section and is rotatable when connecting or disconnecting, that is, when inserting or removing. Good luck. It should be noted that the O-ring 5 moves while rotating along the insertion/removal direction of the chamber 2 . Specifically, when the chamber 2 is inserted, the O-ring 5 rotates counterclockwise so that the inner side moves in the direction of insertion in the plane of FIG. 4(a). Then, when the chamber 2 is pulled out, the O-ring 5 rotates clockwise so that the inner side moves in the pulling direction in the paper plane of FIG. 4(b), that is, clockwise. The inserting/removing direction means that the inserting direction is from the top to the bottom (the direction of the left arrow) in the paper surface of FIG. ). 4(a) and 4(b) indicate the direction in which the O-ring 5 rotates and moves.

(Configuration of Chamber 2)
The chamber 2 has a housing 20 formed by a first housing 21 and a second housing 22, as shown in FIGS. 2(a) and 3(a). An output port 27 is formed integrally with the first housing 21 . A connection port 221 and a connection port 222 are integrally formed on a dome-shaped top surface 220 of the second housing 22 .

The housing 20 is formed using a material that has excellent injection moldability, good machinability, and whose surface roughness can be easily adjusted. Further, the housing 20 is formed using, for example, a material that can be ultrasonically welded. Since the housing 20 may come into contact with human bodily fluids, it is formed using a material that has no biotoxicity and high insulating properties. The housing 20 is thus formed, for example, using polycarbonate. Since the blood flows into the first space 23, the chamber 2 is not reused and is disposable.

The first housing 21 has a flow path 211 formed on its inner bottom surface 210 . Also, the bottom surface 210 has the filter 26 arranged on the channel 211 . This filter 26 is provided so that blood or the like that has flowed into the second space 24 does not flow into the channel 211 . The channel 211 is a passage through which the gas K in the second space 24 flows.

The first housing 21 also has a cylindrical insertion portion 28 with a bottom surface 280 and an output port 27 is provided so as to protrude from the bottom surface 280 . The output port 27 has a cylindrical shape as an example of a cylindrical shape, and the interior of the output port 27 is a flow path 211 . The output port 27 is tapered to form a tapered surface 271 at its tip. In addition, the tip of the output port 27 is not limited to the tapered surface, and may be R-shaped, for example. Moreover, the output port 27 is not limited to a cylindrical shape, and may have a rectangular tubular shape.

The insertion portion 28 has a cylindrical shape surrounding the output port 27 and is integrally formed with the output port 27 . The joint 30 is inserted into the opening 281 of the insertion portion 28 .

Further, the first housing 21 is provided with a protrusion 29 protruding from a side surface 282 of the insertion portion 28, as shown in FIG. 2(a), for example. This protrusion 29 is inserted, for example, into the crank groove 32 of the connecting portion 3 shown in FIG. 2(b). Two protrusions 29 are formed according to the number of crank grooves 32 of the connecting portion 3 . As a modification, the projection 29 may be provided on the connecting portion 3 side, and the crank groove 32 may be provided on the first housing 21 side.

The connection port 221 and the connection port 222 of the second housing 22 are connected to the arterial blood circuit 11 or the venous blood circuit 12 . The blood _R flowing through the arterial blood circuit 11 and the venous blood circuit 12 flows into the first space 23 from the connection port 221 , applies pressure PR to the diaphragm 25 , and flows out from the connection port 222 .

The diaphragm 25 has a dome shape, for example, as shown in FIG. . The diaphragm 25 is formed using a flexible material that can be displaced or deformed following pressure changes in the first space 23 and the second space 24 . Diaphragm 25 is formed using, for example, a flexible sheet such as a synthetic rubber sheet such as silicon rubber or a vinyl chloride sheet that can block blood R and gas K.

(Configuration of connecting portion 3)
For example, as shown in FIGS. 2B and 3B, the connecting portion 3 has a cylindrical guide portion 31 having a bottom surface 310, a joint 30 is provided so as to protrude from the bottom surface 310, The insertion portion 28 of the chamber 2 is inserted into the opening 311 of the guide portion 31 to connect with the chamber 2 . Although the joint 30 and the guide portion 31 of the present embodiment are formed as separate members, they are not limited to this, and may be integrally formed.

Since the connection part 3 is attached to the blood purification device 9, unlike the chamber 2, it is not disposable. Therefore, the connecting portion 3 is formed using a material having high rust resistance, rigidity, chemical resistance, and weather resistance. Therefore, the joint 30 of the connecting portion 3 is formed in a long and narrow cylindrical shape using stainless steel, which is a hard material such as SUS316 or SUS304, but is not limited to this, and may be non-metallic. The guide portion 31 is made of stainless steel such as SUS316 or SUS304, like the joint 30 . The joint 30 of this embodiment is press-fitted into the insertion hole 315 of the guide portion 31 . Further, the joint 30 is not limited to a cylindrical shape, and may have a rectangular tubular shape.

For example, as shown in FIG. 3B, the joint 30 is provided at an end portion 300 facing a connection partner (output port 27), and serves as a retainer for the O-ring 5, and after the connection partner is pulled out. A cap 4 is attached which defines the position of the O-ring 5 . The joint 30 also has a bottom surface 303 facing the cap 4 and spaced apart from the diameter W of the cap 4 and the O-ring 5 .

Specifically, the joint 30 has an insertion opening 301 into which the O-ring 5 is inserted at the end 300 facing the chamber 2 and which communicates with the gas K flow path 305 . A cap 4 is attached to the distal end side of the insertion opening 301 . The insertion opening 301 has a circular cross section perpendicular to the direction of insertion of the output port 27 and has a tip region 304 with a smaller radius near the channel 305 . It is connected. End 272 of output port 27 is inserted into tip region 304 . A terminal end portion 314 of the joint 30 is connected to a tube 10b connected to a pressure sensor 10a of the pressure detection section 10. As shown in FIG.

The upper portion of the end portion 300 of the joint 30 is formed with a tapered surface 306 on the outside and a first fitting portion 307 on the inside. A tapered surface 306 is formed to create a space with the cap 4 . The cap 4 can be easily removed from the joint 30 by inserting a tool into this space and using this principle with the guide portion 31 as a fulcrum.

The first fitting portion 307 includes a first concave portion 307a recessed from the side surface 302 of the insertion opening 301, and a first convex portion 307b whose upper portion has a larger diameter than the side surface 302 and protrudes from the first concave portion 307a. , and the first concave portion 307a and the first convex portion 307b are connected by a smooth curve to form an S shape. This first fitting portion 307 is formed along the circumferential direction of the insertion opening 301 .

In other words, the first fitting portion 307 includes a first convex portion 307b that protrudes from the side surface 302 of the insertion opening 301, and a first concave portion 307a that has a concave shape on the side surface 302. It has an aligned shape.

The guide portion 31 is provided with a tapered surface 313 on the opening 311 side of the upper surface 312 . The upper surface 312 of the guide portion 31 is located higher than the cap 4 as shown in FIG. 3(b). Therefore, there is little trouble that a cloth or the like accidentally touches the cap 4 and comes off from the joint 30 during cleaning or the like.

The guide portion 31 guides the insertion of the insertion portion 28 of the chamber 2 and has a crank groove 32 for holding the state in which the chamber 2 is inserted and the joint 30 and the output port 27 are connected via the O-ring 5. have.

As shown in FIGS. 2(a) and 2(b), the crank groove 32 includes a vertical groove 320 formed along the direction in which the chamber 2 is inserted, and a vertical groove 320 formed perpendicular to the vertical groove 320. and lateral grooves 321. The crank grooves 32 are provided so as to face each other with the joint 30 interposed therebetween.

After the projection 29 of the chamber 2 is inserted into the vertical groove 320 and the output port 27 and the joint 30 are connected, the chamber 2 is rotated leftward on the paper surface of FIG. For example, the connection between the chamber 2 and the connecting portion 3 is locked. A protruding claw portion 311b is formed on a side surface 311a of the opening 311 of the guide portion 31, and the rotation of the chamber 2 with respect to the connection portion 3 is prevented by getting over the convex portion provided on the first housing 21 of the chamber 2. lock.

(Configuration of cap 4)
FIG. 5(a) is a sectional view for explaining an example of the cap according to the first embodiment, and FIG. 5(b) is an enlarged sectional view for explaining an example of the cap. be. FIG. 6A is an example of a top view of the cap according to the first embodiment, and FIG. 6B is an example of a top view of the cap according to the modification. FIG. 7 is a schematic diagram for explaining an example of O-ring replacement according to the first embodiment.

The cap 4 is formed using, for example, a material with high elasticity, toughness, chemical resistance, and weather resistance. The cap 4 of this embodiment is formed using polypropylene, for example.

The cap 4 has an upper portion 40 and a lower portion 41, as shown in FIGS. 4(a) to 5(b), for example. The upper portion 40 has a disk shape. The upper part 40 has rounded corners above the insertion opening 45 .

A step 46 is formed between the upper portion 40 and the lower portion 41 on the insertion opening 45 side. The lower portion 41 has an inclined surface 47 at the end with which the O-ring 5 contacts. This slope 47 converts the direction of the _first force F1 acting on the O-ring 5 into the direction of the _second force F2, as shown in FIG. 4(b). Also, the cap 4 is formed with a second fitting portion 48 that fits with the first fitting portion 307 of the joint 30 .

The second fitting portion 48 includes a second concave portion 48b that fits with the first convex portion 307b, and a second concave portion 48b that increases in clearance toward the lower side of the insertion opening 301 in fitting with the first concave portion 307a. It has two projections 48a. As shown in FIGS. 4A and 4B, the first concave portion 307a of the first fitting portion 307 and the second convex portion 48a of the second fitting portion 48 do not fit together. A gap is generated. This gap is provided to allow the cap 4 to flex when the cap 4 is removed using the principle of leverage described above.

As for cap 4, as shown in Drawing 4 (a) and Drawing 4 (b), for example, it is preferred that end face 40c of upper part 40 is more than side 30a of joint 30. When the end surface 40c of the upper portion 40 is inside the side surface 30a, the gap 7 into which the tool is inserted becomes smaller, and the amount of deflection of the cap 4 becomes smaller, making it difficult to remove the cap 4. As shown in FIG.

The O-ring 5 has an outer diameter greater than the width of the insertion opening 301 of the joint 30, as will be described later. Therefore, when the O-ring 5 is inserted into the insertion opening 301, it is difficult for the O-ring 5 to move down due to its own weight. When the inserted chamber 2 is pulled out from the connecting portion 3, the O-ring 5 moves upward while rotating as the output port 27 moves upward, as indicated by the arrow in FIG. 4(b). A _first force F1 acts on the O-ring 5 due to this movement. The O-ring 5 then contacts the slope 47 of the cap 4 . The slope 47 mainly transforms the _first force F1 in a direction perpendicular to the slope 47, that is, in a direction opposite to the normal direction of the slope 47 to generate a _second force F2. This _second force F2 is a force that presses the cap 4 against the first fitting portion 307, and the fit between the second fitting portion 48 of the cap 4 and the first fitting portion 307 is strong. It is a force in the direction of The _second force F2 also acts radially on the cap 4 because the cap 4 and the O-ring 5 are circular. Therefore, the sealing member pressing structure 1 has a structure that makes it difficult for the O-ring 5 to come off from the joint 30 .

After the chamber 2 is pulled out from the connecting portion 3, the O-ring 5 is positioned above the insertion opening 301 as shown in FIG. 4(a). When inserting the chamber 2 into the connecting portion 3, as shown by the arrow in FIG. Stops moving.

As shown in FIG. 4( a ), in a cross section cut perpendicular to the edge of the insertion opening 301 , the first angle θ ₁ is defined by the reference line S with the upper surface 309 of the joint 30 as a reference and the first angle θ 1 It is assumed that the angle is the angle formed by a straight line L obtained by extending the outline of the slope 47 of the cap ₄ that converts the direction of the force F1 into the direction of the _second force F2. The _second angle θ2 is the angle formed by the reference line S and the straight line M that is in contact with the inflection points of the first convex portion 307b and the first concave portion 307a that form the S shape. The first angle θ ₁ and the third angle θ ₃ are
30°≦θ ₁ ≦60° and θ ₁ ≦θ ₂ ≦90° are satisfied. When this relationship is satisfied, the O-ring 5 presses the slope 47 of the cap 4 to prevent the cap 4 from coming off when the chamber 2 is removed.

In addition, as shown in FIG. 4(a), in a cross section cut perpendicular to the edge of the insertion opening 301, the _third angle θ3 is between the reference line S and S It is the angle formed by the second concave portion 48b forming the character shape and the straight line N that is in contact with the inflection point of the second convex portion 48a. The _second angle θ2 and the _third angle θ3 are
It satisfies θ ₂ ≤ θ ₃ ≤ 90°. When this relationship is satisfied, removal of the cap 4 is facilitated.

Furthermore, the first angle θ ₁ and the _second angle θ ₂ are θ ₁ ≦ _θ2 is satisfied.
Therefore, the first angle θ ₁ to the third angle θ ₃ are
30°≦θ ₁ ≦60° and θ ₁ ≦θ ₂ ≦θ ₃ ≦90° are satisfied.
It is more preferable that 45°<θ ₂ ≦θ ₃ <90°.

In the cap 4 shown in FIG. 5B, the angle _θa between the lower surface 40b of the upper portion 40 and the _second convex portion 48a corresponds to θ3 described above, and satisfies 45°< _θa ≦90°. . The angle θ _b of the slope 47 corresponds to θ ₁ described above and satisfies 30°≦θ _b ≦60°.

Assuming that the length of contact between the first fitting portion 307 of the joint 30 and the second fitting portion 48 of the cap 4 is δ (fitting length), as shown in FIG. When the fitting length .delta. The fitting length δ indicates the width of the contact area in the lateral direction in this cross-sectional view. The contact area is approximately the area of a ring having this width (δ).

As shown in FIG. 7, when the tip 80 of the tool 8 is inserted into the gap 7 formed between the cap 4 and the joint 30 and force is applied by the principle of leverage with the guide portion 31 as a fulcrum, the cap 4 bends. The amount of deflection exceeds the fitting length δ and the cap 4 comes off.

When the O-ring 5 receives a _first upward force F1, for example, as shown in FIGS. 4A and 4B, the first fitting portion 307 and the second fitting portion 48 contact area increases, and the fitting length δ also increases. Therefore, unless the amount of deflection of the cap 4 is larger than normal, the fitting length .delta.

The cap 4 of the present embodiment has a ring shape as shown in FIG. 6(a), but is not limited to this. For example, as shown in FIG. 6B, a cap 4 as a modified example has a notch 49 formed in a part thereof. The modified cap 4 is removed from the joint 30 by shortening the distance of this notch 49 .

(Structure of O-ring 5)
FIG. 8(a) is a schematic diagram for explaining an example of the compression rate of the O-ring according to the first embodiment, and FIG. 8(b) shows a region that is damaged when the O-ring does not rotate. FIG. 8C is a schematic diagram for explaining an example, and FIG. 8C is a schematic diagram for explaining an example of a region that receives damage when the O-ring rotates.

The O-ring 5 is formed in a ring shape using a material with high wear resistance, chemical resistance, elasticity (low compression set), and weather resistance. Furthermore, the O-ring 5 is preferably made of a material with low friction, that is, a small friction coefficient μ, that is, a small frictional resistance. The O-ring 5 of the present embodiment has a rubber hardness of 50° to 80° and is formed into a ring shape using fluororubber that can rotate evenly in the twisting direction. The O-ring 5 may be made of any material as long as it functions as a sealing member, and the frictional resistance may be reduced by coating the surface of the O-ring 5 .

Using the width D ₁ of the output port 27 of the chamber 2, the diameter D ₂ of the insertion opening 301 of the joint 30, and the diameter W of the O-ring 5, the relationship shown in the following equation (1) is established.
0<1−(D ₂ −D ₁ )/2W<α (1)
When this formula (1) is satisfied, the O-ring 5 rotates and moves with respect to insertion/removal while maintaining sealing performance. Typical crush amounts are around 8-25%. The threshold α has different values depending on the materials, dimensions, and surface conditions of the output port 27, the joint 30, and the O-ring 5. FIG. In addition, although the general crushing amount is about 8 to 25% ("1-(D ₂ -D ₁ )/2W" is 0.08 to 0.25), the crushing amount of the present embodiment is, for example, ten and several percent.

As shown in FIG. 8(b), a mounting groove 30b to which the O-ring 5 is mounted is formed in the fixed wall 30a. When the O-ring 5 is restrained to be non-rotatable by contact, if the sliding member 27a moves downward while contacting the O-ring 5, the O-ring 5 cannot rotate. 55 takes a lot of damage.

On the other hand, as shown in FIG. 8(c), even if the O-ring 5 contacts the first stopper 30c (upper surface) and the second stopper 30d (lower surface) of the mounting groove 30b, the O-ring 5 is not restrained so as not to rotate. When the moving member 27a moves downward while contacting the O-ring 5, the O-ring 5 rotates and moves downward, so that the damaged area 55 is dispersed between the mounting groove 30b side and the sliding member 27a side. . That is, the area 55 shown in FIG. 8C is wider than the area 55 shown in FIG. 8B. Therefore, the O-ring 5 is less prone to surface roughness due to insertion/removal, is less damaged, has high insertion/removal durability, and has a long service life.

As shown in FIG. 8A, the distance L over which the O-ring 5 can move is determined according to the stroke from the contact of the output port 27 with the O-ring 5 to the end of the connection. larger than the diameter W. Note that the distance L is the distance from the top of the slope 47 of the cap 4 to the bottom surface 303 .

As mentioned above, chamber 2 is disposable. However, since the connection part 3 is attached to the main body 90 of the blood purification device 9, it is not disposable. Since the O-ring 5 is preferably reusable rather than disposable from the viewpoint of cost, it is arranged in the connecting portion 3, but if it is repeatedly inserted and removed, it deteriorates, pressure leakage occurs, and detection accuracy decreases. Since the pressing structure 1 of the sealing member of the present embodiment is configured so that the O-ring 5 rolls and moves, the service life is extended until the detection accuracy deteriorates.

(Regarding attachment of chamber 2 and connecting part 3)
9(a) to 9(d) are schematic diagrams showing an example of connection between the chamber and the connection part in the connection structure according to the first embodiment. 10(a) to 10(c) are cross-sectional views showing an example of connection between the chamber and the connection part in the connection structure according to the first embodiment. The connection part 3 will be described as being fixed to the main body 90 of the blood purification device 9 .

As shown in FIGS. 9(a) and 10(a), the tip of the insertion portion 28 of the chamber 2 is inserted into the opening 311 of the connecting portion 3, and the longitudinal groove 320 of the connecting portion 3 and the projection 29 of the chamber 2 are positioned. to match. At this time, the insertion portion 28 of the chamber 2 is guided by the guide portion 31 and inserted into the opening 311 .

Next, as shown in FIGS. 9B and 10B, when the chamber 2 is further pushed into the connecting portion 3, the O-ring 5 contacts the tapered surface 271 of the output port 27. As shown in FIG. In the sealing member pressing structure 1, the distance from the start of guidance by the guide portion 31 to the contact of the output port 27 with the O-ring 5 is long, that is, the distance over which the insertion portion 28 moves while being guided by the opening 311 is sufficiently long. As a result, tilting of the chamber 2 can be suppressed, and the output port 27 can be vertically inserted into the insertion opening 50 of the O-ring 5 . If this distance is short, the output port 27 may be tilted and inserted into the O-ring 5 . As shown in FIG. 10( a ), when the guide portion 31 starts guiding the insertion portion 28 , the distance L ₂ from this guide start point to the apex of the O-ring 5 is the distance between the tip of the output port 27 and the insertion portion 28 . longer than the distance L ₁ to the lower surface 283 .

Next, as shown in FIGS. 9(c) and 10(c), when the chamber 2 is further pushed into the connecting portion 3, the lower surface 183 of the chamber 2 comes into contact with the bottom surface 310 of the connecting portion 3, and the insertion is completed. At this time, since the output port 27 moves while pushing down the O-ring 5, the O-ring 5 moves downward while rotating. The O-ring 5 then contacts the bottom surface 303 of the joint 30 . At this time, the protrusion 29 of the chamber 2 can move to the lateral groove 321 .

Next, as shown in FIG. 9(d), the chamber 2 is rotated to move the protrusion 29 into the lateral groove 321, and the chamber 2 and the connecting portion 3 are locked. When removing the chamber 2, the above procedure is reversed. The O-ring 5 moves while rotating upward according to the movement of the output port 27 and stays in a position to contact the cap 4 .

(Effect of the first embodiment)
The sealing member pressing structure 1 according to the present embodiment can reduce maintenance costs. Specifically, in the sealing member pressing structure 1 , the O-ring 5 is prevented from coming off by the cap 4 . Since the cap 4 can be easily removed using a tool, the time required to replace the O-ring 5 can be shortened. Therefore, the sealing member pressing structure 1 improves the workability of replacing the O-ring 5 during maintenance, and can suppress scratches on the sealing surface 51 of the O-ring 5 (the surface of the O-ring 5) during the work.

Since the first fitting portion 307 and the second fitting portion 48 of the pressing structure 1 for the seal member have an S-shape, they are easier to remove than when this configuration is not employed. . Therefore, in the sealing member pressing structure 1, the cap 4 can be easily removed and the O-ring 5 can be replaced. It is suppressed that it hurts with etc.

When the chamber 2 is removed from the joint 30 , the pressing structure 1 for the seal member holds the second fitting portion 48 of the cap 4 against the first fitting portion of the joint 30 even if force is applied to the O-ring 5 in the direction in which the O-ring 5 is pulled out. Since the force is converted into a force that presses against the joint portion 307, the O-ring 5 is prevented from coming off unintentionally due to repeated insertion and removal, compared to the case where this configuration is not employed.

In the sealing member pressing structure 1, when the chamber 2 is inserted into or removed from the connecting portion 3, the output port 27 and the O-ring 5 come into contact with each other and the O-ring 5 moves while rotating. , the O-ring 5 is less damaged when the chamber 2 is inserted and removed, that is, the damage to the sealing surface 51 of the O-ring 5 is suppressed, and the insertion and removal durability is high. Further, since the pressing structure 1 for the sealing member has high insertion/removal durability of the O-ring 5, the replacement cycle becomes longer, and the maintenance cost and operation cost can be suppressed. Furthermore, since the sealing member pressing structure 1 has high insertion/removal durability of the O-ring 5, the sealing property is good, and the pressure detection accuracy of the pressure sensor 10a is stabilized.

The blood purification apparatus 9 employs the pressing structure 1 for the sealing member, thereby prolonging the replacement cycle of the O-ring 5 and maintaining the detection accuracy of the pressure of the blood R for a long period of time, thereby reducing maintenance and operating costs. performance can be maintained for a long time while being suppressed.

[Second embodiment]
The second embodiment differs from the other embodiments in the shape of the cap 4 .

FIG. 11(a) is a schematic diagram showing an example of the cap according to the second embodiment, and FIG. 11(b) is an enlarged view of an example of the cross section of the cap. In the embodiments described below, portions having the same functions and configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof will be omitted.

In the cap 4 shown in FIGS. 11(a) and 11( _b ), the angle θa between the lower surface 40b of the upper portion 40 and the _second convex portion 48a corresponds to θ3 described above, and 45°<θa≦45°< _θa ≦ 90° is satisfied. The angle θ _b of the slope 47 corresponds to θ ₁ described above and satisfies 30°≦θ _b ≦60°.

The cap 4 of the present embodiment has a shape different from that of the cap 4 of the first embodiment, but satisfies the above-described relationship. Become.

[Third embodiment]
3rd Embodiment differs in the shape of the 1st fitting part 307 and the 2nd fitting part 48. As shown in FIG.

FIG. 11(c) is a schematic diagram showing an example of a first fitting portion and a second fitting portion according to the third embodiment. As shown in FIG. 11C, the first fitting portion 307 and the second fitting portion 48 have a linear shape instead of an S shape. The fitting between the first fitting portion 307 and the second fitting portion 48 is more difficult to come off than the S-shaped fitting.

However, in the sealing member pressing structure 1 of the present embodiment, the tip 80 of the tool 8 can be inserted into the gap 7 formed between the cap 4 and the joint 30. can be easily removed using

[Fourth embodiment]
The fourth embodiment differs from the other embodiments in that the pressure detector 10 is arranged before and after the blood pump 113 .

FIG. 12 is a schematic diagram showing an example configuration of a blood purification apparatus according to a fourth embodiment. Pressure detection unit 10 of the present embodiment is additionally arranged between clamp 112 of arterial blood circuit 11 and blood pump 113 , that is, arranged before and after blood pump 113 , as shown in FIG. 12 .

Therefore, the blood purification apparatus 9 can detect the blood pressure before and after the blood pump 113, so that the blood pump 113 can be controlled more appropriately than in the case of either one of them. Accuracy of management is improved. In blood purification apparatus 9, even if the number of pressure detection units 10 is increased, O-ring 5 can have a longer life by adopting sealing member holding structure 1. Operating costs can be reduced.

[Fifth embodiment]
The fifth embodiment differs from the other embodiments in that the cap 4 and the joint 30 are screwed together.

FIG. 13(a) is a perspective view showing an example of a connection structure according to a fifth embodiment, FIG. 13(b) is a cross-sectional view showing an example of a cap, and FIG. FIG. 3 is a side view showing an example of a joint; FIG. 14(a) is a cross-sectional view showing an example of a joint to which a cap is attached according to the fifth embodiment, and FIG. 14(b) is a cross-sectional view showing an example of connecting a chamber to a connecting portion. be. In addition, the chamber 2 shown in FIG.14(b) shows only the 1st housing 21 in figure.

As shown in FIGS. 13(a) to 14(b), for example, the sealing member pressing structure 1 of the present embodiment has a cap 4 and a joint 30 that are screwed together.

The cap 4 is formed in a cylindrical shape using a resin material or a metal material. The cap 4 also has an internal space 45a that communicates with an insertion opening 45 into which the output port 27 is inserted, as shown in FIG. 13(b). A second fitting portion 48 is provided on the inner wall 45b of the inner space 45a. The second fitting portion 48 of the present embodiment is configured as a female screw portion 48c.

The insertion opening 45 of this embodiment has a hexagonal shape, as shown in FIG. 13(a). Accordingly, the cap 4 is screwed to the joint 30 by inserting a hexagonal wrench corresponding to this insertion opening 45 and rotating it with respect to the joint 30 .

The shape of the insertion opening 45 is not limited to a hexagonal shape, and may be a shape that allows the output port 27 of the chamber 2 to be inserted and a shape corresponding to the shape of a tool such as a hex lobe to be used. Also, the cap 4 may have a hexagonal shape or the like to which a tool such as a socket wrench can be fitted.

As shown in FIG. 13(c), the joint 30 is provided with a first fitting portion 307 at the upper end portion 300. As shown in FIG. The first fitting portion 307 of this embodiment is configured as a male screw portion 307c. After the O-ring 5 is placed in the insertion opening 301 of the joint 30, the female threaded portion 48c of the cap 4 is inserted into the male threaded portion 307c. By rotating the cap 4 with respect to the joint 30 , the female threaded portion 48 c and the male threaded portion 307 c are threadedly coupled to connect the cap 4 and the joint 30 .

Since the second fitting portion 48 of the cap 4 and the first fitting portion 307 of the connecting portion 3 are connected by screw connection, the sealing member pressing structure 1 of the present embodiment does not employ this configuration. Removal of the cap 4 becomes easier than in the case. In addition, since the sealing member pressing structure 1 can remove the cap 4 by inserting a tool into the insertion opening 45 of the cap 4, the removal of the cap 4 becomes easier than when this structure is not adopted. Damage to the guide portion 31 and the like with a tool is suppressed.

According to the sealing member pressing structure 1 of at least one embodiment described above, it is possible to improve the workability at the time of replacing the sealing member.

(Summary of embodiment)
Next, the technical ideas understood from the above-described multiple embodiments will be described with reference to the reference numerals and the like in the embodiments. However, each reference numeral in the following description does not limit the constituent elements in the claims to the members specifically shown in the embodiment.

[1] A fitting member (joint 30) having an insertion opening (301) and having a first fitting portion 307 provided on a side surface 302 of the insertion opening (301);
a sealing member (O-ring 5) arranged in the insertion opening (301) of the fitting member (joint 30);
Attached to the insertion opening (301), when a first force (F ₁ ) directed outward from the insertion opening (301) acts on the sealing member (O-ring 5), the first force ( F ₁ ) received from the seal member (O-ring 5) acting on the second fitting portion (48) that fits into the first fitting portion (307) by a second force (F ₂ ) received from the sealing member (O-ring 5). a cap (4);
A sealing member pressing structure (1) comprising:

[2] The cap (4) converts the direction of the first force (F ₁ ) into the direction of the second force (F ₂ ) at the portion that contacts the seal member (O-ring 5). having a slope (47);
[1] holding structure (1) for a sealing member.

[3] The first fitting portion (307) includes a first projection (307b) projecting from the side surface (302) of the insertion opening (301) and the side surface (302) having a concave shape. The first recess (307a) recessed into the insertion opening (301) has a shape arranged in order from the upstream side in the insertion direction,
The second fitting portion (48) includes a second concave portion (48b) that fits with the first convex portion (307b), and the insertion opening (48b) that fits with the first concave portion (307a). 301) has a second protrusion (48a) whose gap increases toward the downstream side in the insertion direction,
A pressing structure (1) for a sealing member according to [1] or [2].

[4] The first fitting portion (307) is formed in an S shape by the first protrusion (307b) and the first recess (307a),
The second fitting portion (48) has an S shape formed by the second concave portion (48b) and the second convex portion (48a),
The pressing structure (1) for the seal member according to [3].

[5] In a cross section cut perpendicular to the edge of the insertion opening (301),
A reference line (S) based on the upper surface (309) of the fitting member (joint 30) and transforming the direction of the first force (F ₁ ) to the direction of the second force (F ₂ ) A _first angle ? a second angle θ ₂ between the convex portion (307b) and a straight line (M) contacting the inflection point of the first concave portion (307a);
satisfying 30° ≤ θ ₁ ≤ 60° and satisfying θ ₁ ≤ θ ₂ ≤ 90°;
A pressing structure (1) for a sealing member according to [3] or [4].

[6] In a cross section cut perpendicular to the edge of the insertion opening (301),
A reference line (S) based on the upper surface (309) of the fitting member (joint 30), and a variation of the first protrusion (307b) and the first recess (307a) forming an S shape. A straight line (M) tangent to the curved point, a second angle θ ₂ formed by the reference line (S), the second concave portion (48b) and the second convex portion ( 48a) and the straight line (N) tangent to the point of inflection, the _third angle θ3 is
satisfying θ ₂ ≤ θ ₃ ≤ 90°,
A pressing structure (1) for a sealing member according to any one of [3] to [5].

[7] The fitting member includes a hollow housing (20), a diaphragm (25) that divides the interior of the housing (20) into a first space (23) and a second space (24), and the first space (24). A chamber having an output port (27) for outputting the gas (K) in the second space (24) as the diaphragm (25) is deformed by the pressure of the fluid (blood R) flowing into the space (23) of A joint (30) connected to the output port (27) of (2),
The sealing member (O-ring 5) is sandwiched between the side surface (270) of the output port (27) and the side surface (302) of the joint (30) to connect the chamber (2) and the connecting portion (3). Move while rotating when inserting or removing,
A sealing member pressing structure (1) according to any one of [1] to [6].

[8] Having the pressing structure according to any one of [1] to [7],
A blood purification device that purifies human blood.

[9] A first force ( F ₁ ), the second force (F ₂ ) received from the seal member (O-ring 5) on which the first force (F ₁ ) acts is applied to the member (joint 30) A cap (4) with a second fitting (48) that mates with the first fitting (307).

Although several embodiments of the present invention have been described above, these embodiments are merely examples and do not limit the invention according to the claims. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, etc. can be made without departing from the scope of the present invention. Moreover, not all the combinations of features described in these embodiments are essential to the means for solving the problems of the invention. Furthermore, these embodiments are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and their equivalents.

DESCRIPTION OF SYMBOLS 1... Sealing member holding structure, 2... Chamber, 3... Connection portion, 4... Cap, 5... O-ring, 7... Gap, 8... Tool, 9... Blood purifier, 10... Pressure detector, 10a... Pressure sensor 10b tube 11 arterial blood circuit 12 venous blood circuit 13 dialyzer 13a blood inlet 13b blood outlet 13c dialysate inlet 13d dialysate outlet 14 ... dialysate introduction line, 15 ... dialysate discharge line, 16 ... double pump, 17 ... dewatering pump, 20 ... housing, 21 ... first housing, 22 ... second housing, 23 ... first space, 24 Second space 25 Diaphragm 26 Filter 27 Output port 27a Sliding member 28 Insertion portion 29 Projection 30 Joint 30a Side 30a Fixed wall 30b Mounting Groove 30c First stopper 30d Second stopper 31 Guide part 32 Crank groove 40 Upper part 40b Lower surface 40c End surface 41 Lower part 45 Insertion opening 45a Inside Space 46 Step 47 Slope 48 Second fitting portion 48 a Second convex portion 48 b Second concave portion 48 c Female screw portion 49 Notch 50 Insertion opening 51 Seal surface 55 Region 80 Tip 90 Body 101 Panel 110 Arterial puncture needle 111 Connector 112 Clamp 113 Blood pump 120 Venous puncture needle 121 Connector DESCRIPTION OF SYMBOLS 122... Blood discrimination|determination part 123... Clamp 124... Bubble detection part 125... Vein chamber 183... Lower surface 210... Bottom surface 211... Flow path 220... Upper surface 221... Connection port 222... Connection port 271... Taper surface 272 end 280 bottom 281 opening 282 side 283 lower surface 300 end 301 insertion opening 302 side 303 bottom 304 tip region 305 stream Path 306 Tapered surface 307 First fitting portion 307a First concave portion 307b First convex portion 307c Male screw portion 309 Top surface 310 Bottom surface 311 Opening 311a Side surface 311b Claw portion 312 Upper surface 313 Tapered surface 314 End portion 315 Insertion hole 320 Vertical groove 321 Lateral groove

Claims (7)

a fitting member having an insertion opening and having a first fitting portion provided on a side surface of the insertion opening;
a seal member disposed in the insertion opening of the fitting member;
When a first force acting on the sealing member attached to the insertion opening and directed outwardly from the insertion opening acts on the sealing member, a second force received from the sealing member on which the first force acts causes the second force to move the sealing member. a cap having a second fitting portion that fits with the first fitting portion;
with
The cap has a sloping surface that converts the direction of the first force into the direction of the second force at a portion that contacts the seal member.
The holding structure of the seal member. The first fitting portion includes a first convex portion that protrudes from the side surface of the insertion opening and a first concave portion that has a concave shape on the side surface and is arranged in order from the upstream side of the insertion opening in the insertion direction. having the shape
The second fitting portion includes a second concave portion that fits with the first convex portion, and a second concave portion that increases toward the downstream side in the insertion direction of the insertion opening in the fitting with the first concave portion. having 2 protrusions,
The structure for holding down the sealing member according to claim 1 . the first fitting portion is formed in an S shape by the first convex portion and the first concave portion;
The second fitting portion has an S shape formed by the second concave portion and the second convex portion,
3. The structure for holding down the seal member according to claim 2. In a cross section cut perpendicular to the edge of the insertion opening,
A first line formed by a reference line based on the upper surface of the fitting member and a straight line extending the outline of the slope of the cap that converts the direction of the first force to the direction of the second force. The angle θ ₁ and the second angle θ ₂ formed by the reference line and the straight line contacting the inflection points of the first convex portion and the first concave portion forming the S shape are
satisfying 30° ≤ θ ₁ ≤ 60° and satisfying θ ₁ ≤ θ ₂ ≤ 90°;
4. A pressing structure for a seal member according to claim 2 or 3. In a cross section cut perpendicular to the edge of the insertion opening,
a second angle θ ₂ formed between a reference line based on the upper surface of the fitting member and a straight line contacting an inflection point of the first protrusion and the first recess forming an S shape; and a _third angle θ3 between the reference line and a straight line that touches the inflection points of the second concave portion and the second convex portion that form an S shape,
satisfying θ ₂ ≤ θ ₃ ≤ 90°,
5. The sealing member holding structure according to claim 2. The fitting member includes a hollow housing, a diaphragm that divides the inside of the housing into a first space and a second space, and a pressure of a fluid that flows into the first space. A joint connected to the output port of a chamber having an output port for outputting gas in two spaces,
The seal member is sandwiched between the side surface of the output port and the side surface of the joint, and moves while rotating when connecting or disconnecting the chamber and the joint.
The structure for holding down the sealing member according to any one of claims 1 to 5. Having the sealing member pressing structure according to any one of claims 1 to 6,
A blood purification device that purifies human blood.

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