JP5177215B2 - In-circuit pressure sensor detection unit, in-circuit pressure sensor - Google Patents

Description

  The present invention relates to a blood purification device that processes blood derived from a human body and injects a chemical solution into the human body, and more particularly to a detection unit used in an in-circuit pressure sensor that detects a pressure in a liquid circuit applied to a dialysis machine.

  When blood purification therapy is performed, the patient's blood is led out of the body, and after passing this blood through a filter, it is removed by a blood circuit that returns the blood to the patient again, a dialysate circuit that circulates dialysate, and dialysis and filtration. A liquid circuit such as a replacement fluid circuit that replenishes water in the blood is constructed using a tube or the like.

  Information on the liquid flowing in the liquid circuit, particularly blood pressure flowing in the blood circuit, is important information for controlling the dialysis state. As a method for measuring the pressure in the blood circuit, conventionally, a circuit branching from the blood circuit is separately provided and the pressure is measured by a mercury column or the like at the end of the branched circuit, and a diaphragm is provided in the blood circuit. And a method of directly detecting the pressure in the blood circuit from the state of appearance of the diaphragm (for example, Patent Document 1 and Patent Document 2).

  When the pressure in the blood circuit is directly detected using a diaphragm, a special operation is not required for priming compared to the case of measuring using a mercury column, and priming can be easily performed. In addition, since a branch path is not necessary, blood stagnation is reduced, and the risk of blood clotting can be avoided.

  The conventional diaphragm type detection unit includes a tubular body disposed in a blood circuit, and a diaphragm is disposed on an end face of an opening provided on a peripheral wall of the hospitality, and seals the opening. The pressure is detected based on the state of the diaphragm. Then, as a method of bringing the diaphragm into close contact with the opening in a liquid-tight state, as shown in FIG. 14, a method in which a plurality of upper and lower pedestals 1 and 2 provided on the periphery of the opening sandwich the periphery of the diaphragm 3. Is adopted.

JP 2003-139635 A Japanese Patent Laid-Open No. 9-024026

  However, in the method of holding by holding the peripheral edge of the diaphragm 1, the diaphragm 3 is pressed with the pedestals 1 and 2 (in FIG. 14) in order to counter the pressure (large arrow in FIG. 14) applied from the fluid. It is necessary to pinch with a small arrow). As a result, the diaphragm 3 continues to be sandwiched with a large pressure, and the risk of breakage is high.

  Furthermore, the pedestals 1 and 2 that must hold the diaphragm 3 in a pressurized state have a high risk of damage due to stress concentration.

  As a result of diligent efforts and research, the inventors of the present invention give excessive pressure not only to the diaphragm but also to the pedestal by gripping the diaphragm from a direction different from the direction of pressure applied from the fluid. Thus, the inventors have found out that the diaphragm can be held while maintaining liquid tightness, and have found a structure capable of realizing the above state.

  Furthermore, the detection unit has also been found to be less likely to be damaged even when the diaphragm appears and disappears repeatedly due to pressure fluctuations.

  An object of the present invention is to provide a detection unit for an in-circuit pressure sensor capable of ensuring a necessary and sufficient pressure resistance performance without strongly holding a diaphragm and capable of preventing the diaphragm from being damaged based on the knowledge of the inventors. And

  In order to achieve the above object, a detection unit for a circuit internal pressure sensor according to the present invention is a detection unit used for a circuit internal pressure sensor for detecting a pressure in a liquid circuit through which a liquid flows, and is interposed in the liquid circuit. A base body that is disposed and has an opening, a cylindrical cap housing that surrounds the opening, and a diaphragm that seals the opening, and that is in contact with the inner peripheral wall of the cap housing And a thin annular thin portion provided integrally inside the intermediate portion in the direction of pressure detected by the fixed portion, and a disc-shaped displacement portion connected integrally with the thin portion. A diaphragm, an inlet for introducing liquid into the substrate, and an outlet for discharging liquid from the substrate are provided.

  With the fixing portion, it is possible to stabilize the shape of the entire diaphragm and improve the accuracy of changes in the diaphragm due to pressure fluctuations.

  Further, since the fixed portion and the cap housing portion are in contact with each other in a direction intersecting with the pressure direction detected, a large friction is generated between the fixed housing and the cap housing portion when attempting to move in the direction of the pressure detected by the entire diaphragm. A force is generated, and it is possible to prevent the diaphragm from being displaced or detached from the substrate.

It is a perspective view which cuts and shows a detection unit partially. It is a perspective view which shows a diaphragm. It is sectional drawing which shows a diaphragm (II line in FIG. 2). It is sectional drawing which shows a base | substrate. It is sectional drawing which shows a cap. It is sectional drawing which shows the state which attaches a diaphragm to a base | substrate. It is sectional drawing which shows the state which inserts a cap in a cap accommodating part. It is sectional drawing which shows a detection unit. It is a perspective view which shows the detection unit interposed by the liquid circuit attached to a dialysis machine. It is sectional drawing which shows a circuit internal pressure sensor. It is typical sectional drawing for demonstrating the dimension state of a diaphragm and a fitting groove. It is sectional drawing which shows the attachment modified example of a diaphragm. It is sectional drawing which shows the attachment modified example of another diaphragm. It is sectional drawing which shows the holding state of the conventional diaphragm.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing the detection unit 100 with a part cut away.

  As shown in the figure, the detection unit 100 includes a diaphragm 110, a base 120, and a cap 130 as a regulating means.

FIG. 2 is a perspective view showing the diaphragm 110.
FIG. 3 is a sectional view showing the diaphragm 110 (II line in FIG. 2).

  When the pressure of the liquid flowing in the base 120 is larger than the atmospheric pressure (positive pressure), the diaphragm 110 expands and protrudes in a convex shape, and when the pressure of the liquid flowing in the base 120 is smaller than the atmospheric pressure ( (Negative pressure) has a generally disc shape that is recessed into a concave shape, and is made of a resin that can realize flexibility.

  Examples of the resin constituting the diaphragm 110 include polyvinyl chloride, SEBS-based elastomer, silicon rubber, and isoprene rubber. Silicon rubber and isoprene rubber are particularly preferable. Silicone rubber and isoprene rubber are preferable because they are flexible, easy to process, and have no negative influence on the fluid (blood) to be measured.

  The diaphragm 110 includes a cylindrical fixing portion 111 having one end portion serving as a close-contact portion 112, a thin annular thin portion 114 provided on the inner side of the fixing portion 111, and an integral portion with the thin portion 114. And a disc-shaped displacement portion 115 to be connected. A magnet 113 is provided at the center of the displacement portion 115 (that is, the center of the diaphragm 110).

  The fixing portion 111 is a portion that fixes the diaphragm 110 to the base body 120 and abuts against the cap 130, is located on the outermost periphery of the diaphragm 110, and stands vertically with respect to the surface of the diaphragm 110. By adopting such a structure, the fixing portion 111 plays a role of stabilizing the shape of the entire diaphragm 110 and improving the accuracy of change of the displacement portion 115 due to pressure fluctuation.

  The portion below the thin portion 114 of the fixed portion 111 also functions as a protrusion protruding from the diaphragm 110 main body, and fits into a fitting groove described later provided on the periphery of the opening of the base body 120. . And since the fixing | fixed part 111 fitted to a fitting groove closely_contact | adheres with the surrounding wall of a fitting groove | channel, the lower surface of the fixing | fixed part 111 is functioning also as the contact part 112. FIG.

  The thin portion 114 is a thin annular portion that connects the relatively rigid fixed portion 111 and the relatively thick displacement portion 115 together. The thin portion 114 can change the displacement portion 115 following a subtle change in pressure.

  The displacement part 115 is a disk-shaped part connected integrally with the thin part 114. The displacement portion 115 holds the magnet 113 and is relatively thick so that the magnet 113 can be displaced along the pressure direction.

  The magnet 113 is a member that is displaced together with the displacement portion 115 and has a columnar shape having an inverted T shape in cross section. By detecting the displacement amount of the magnet 113 by a load cell described later, the displacement amount of the diaphragm 110 can be detected, and the pressure of the liquid can be measured in terms of the displacement amount.

FIG. 4 is a cross-sectional view showing the base 120.
As shown in the figure, the base body 120 is made of a rigid resin, and surrounds the tubular portion 125 disposed in the liquid circuit, the opening portion 122 opening the peripheral wall of the annular portion 125 in a circular shape, and the opening portion. A cylindrical cap housing portion 124 and a fitting groove 123 are provided.

  One end of the tubular portion 125 functions as an inlet portion into which liquid is introduced, and the other end functions as an outlet portion. The inlet portion and the outlet portion function as cocks 121 inserted into the end portions of the tubes constituting the liquid circuit, and the surface of the cock 121 has a bamboo shoot shape (not shown) so that the inserted tubes do not fall out. ).

  The fitting groove 123 is a ring-shaped portion surrounding the opening 122 and is formed by a cylindrical cap housing portion 124 and a cylindrical inner peripheral wall 129 standing integrally therewithin.

  The cap accommodating portion 124 is a cylindrical portion that accommodates a cap 130 described later, and is erected integrally with the annular portion 125 so as to surround the opening 122. In addition, a plurality of first through holes 126 are provided on the peripheral wall of the cap accommodating portion 124 for locking the accommodated cap 130.

FIG. 5 is a cross-sectional view showing the cap 130.
As shown in the figure, the cap 130 is an annular member that can be fitted into the cap housing portion 124, and a second through hole 127 corresponding to the first through hole 126 is provided in the radial direction. . The cap 130 is made of resin.

Next, the assembly procedure of the detection unit 100 will be described.
First, as shown in FIG. 6, after the diaphragm 110 is inserted into the cap housing portion 124, the diaphragm 110 is pressed against the opening 122 of the base 120 using the insertion jig 140, and the lower portion of the fixing portion 111 as a protrusion is fitted. Insert into the mating groove 123.

  Here, the insertion jig used for attaching the diaphragm 110 is a columnar member having a diameter that can be smoothly inserted into the cap housing portion 124. Further, an annular projecting portion 141 is integrally provided so that the insertion jig comes into contact with only the fixed portion 111 of the diaphragm 110.

  In this way, by using an insertion jig that can be inserted smoothly as the cap housing portion 124, the diaphragm 110 is made to have a uniform circumferential force with respect to the opening portion 122 of the base 120 and parallel to the opening portion 122. The diaphragm 110 can be attached to the base 120 without being distorted.

  Further, when the diaphragm 110 is attached to the base 120, it is desirable to apply and apply a volatile liquid. This is because the liquid functions as a lubricant and the fixing portion 111 can be easily inserted into the fitting groove 123. Further, the use of a volatile lubricant is because the detection unit 100 may be used in a blood circuit, and the blood that has passed through the detection unit 100 may be returned to the human body, so that it disappears due to volatilization. Because it can be expected. As the volatile liquid, alcohol is preferable, and methanol and ethanol are particularly hygienic. It is easy to obtain and easy to handle.

  Next, as shown in FIG. 7, the cap 130 is inserted into the cap housing portion 124. The fitting tolerance between the cap 130 and the cap housing portion 124 is large, and the cap 130 reaches the diaphragm 110 simply by dropping the cap 130 into the cap housing portion 124.

  The accommodated cap 130 is rotated so that the first through hole 126 and the second through hole 127 are aligned.

  Finally, scissors are inserted into the first through hole 126 on the peripheral wall of the cap housing portion 124 and the second through hole 127 of the cap 130 in a skewered manner.

  By the above procedure, the detection unit 100 as shown in FIG. 8 is completed. As described above, the detection unit 100 can be easily assembled, and the assembly cost can be reduced.

  In the assembled detection unit 100, the cap 130 is in slight contact with the upper end surface of the fixed portion 111 of the diaphragm 110, but no pressing force is generated from the cap 130 to the fixed portion 111. As described above, the cap 130 in which the cap 130 is fixed to the cap housing portion 124 by the scissors functions as a restricting means that locks the fixing portion 111 even when positive pressure is applied to the diaphragm 110 and restricts the displacement of the close contact portion 112. It does not apply a force from the cap 130 to the diaphragm 110 to provide an adhesion force or the like.

  Further, as shown in FIG. 8, the lower portion of the fixed portion 111 of the diaphragm 110 is attached to a fitting groove 123 provided at the periphery of the opening 122 of the base 120 in a forced fitting state. Accordingly, the inner peripheral wall 129 and the contact portion 122 are in close contact with each other in a liquid-tight state in a direction perpendicular to the direction of the flow path pressure detected (white arrow in the figure). Further, this adhesion force is generated by the elasticity of the fixing portion 111 that is forcibly fitted between the cap housing portion 124 and the inner peripheral wall 129, and is generated only in a direction substantially perpendicular to the direction of the detected pressure. Therefore, the displacement part 115 and the thin part 114 of the diaphragm 110 are not affected. Therefore, since the adhesion force for sealing the opening 122 does not affect the pressure detection, the detection unit 100 with high measurement accuracy can be provided. In addition, since the distance between the portion compressed to give the adhesion force and the portion displaced due to pressure fluctuation is longer than in the conventional example, the resin constituting the diaphragm 110 is less burdened, and cracks and stress cracks Etc. are less likely to occur. Therefore, it is effective in preventing the diaphragm 110 from being damaged.

  FIG. 9 is a view showing the detection unit 100 disposed in the blood circuit as a liquid circuit attached to the dialysis machine from the back side.

  As shown in the figure, the detection unit 100 is interposed in the blood circuit before and after the dialyzer used for dialysis, and detects the blood pressure during dialysis in real time.

FIG. 10 is a cross-sectional view showing the circuit internal pressure sensor 200.
As shown in the figure, the circuit internal pressure sensor 200 includes the detection unit 100 described above, and a sensor unit including a load cell 151 that detects the displacement of the magnet 113 that moves in and out in response to the movement of the diaphragm 110 and converts it into an electrical signal. 150.

  The load cell 151 is biased in a projecting manner with respect to the sensor unit 150 main body. This is because not only the displacement when the diaphragm 110 protrudes but also the displacement when the diaphragm 110 is depressed and converts the displacement into an electric signal.

  In the case of the apparatus configuration shown in FIG. 9, the sensor unit 150 is incorporated in a dialysis machine.

  According to the in-circuit pressure sensor as described above, the detection unit 100 that directly contacts blood or the like is disposable, and the relatively expensive sensor unit 150 can be reused because it does not come into contact with blood or the like, and is disposable. Since the attachment and detachment between the detection unit 100 and the sensor unit 150 that is used repeatedly can be performed easily and smoothly, it is excellent in convenience. Moreover, the running cost of the circuit internal pressure sensor 200 can be reduced.

Next, an embodiment of the detection unit 100 will be described.
FIG. 11 is a schematic cross-sectional view for explaining the dimensional state of the diaphragm 110 and the fitting groove 123. For ease of explanation, hatching on the base 120 side is omitted.

  As shown in the figure, the outside diameter of the fixed portion 111 of the diaphragm 110 fitted in the fitting groove 123 is DD, the inside diameter is DE, the outside diameter of the fitting groove 123 is DO, and the inside diameter is DI. And

  The relationship between DD and DE is preferably DO ≧ DD, and preferably 0.96 × DO ≦ DD ≦ 1.0 × DO. When DD is larger than DO, the entire diaphragm 110 is compressed by the outer peripheral wall of the fitting groove 123 and the surface of the diaphragm 110 is distorted, and a desired measurement accuracy cannot be obtained. When DD is smaller than 0.96 × DO, the fixing portion 111 is bent and a desired adhesion force cannot be obtained, and a leak occurs.

  The relationship between DO and DI is preferably DI> DE, and preferably 0.96 × DI ≦ DE ≦ 0.97 × DI. When DE is smaller than 0.96 × DI, the entire diaphragm 110 is expanded by the inner peripheral wall of the fitting groove 123, and the elasticity of the diaphragm 110 is changed, so that a desired measurement accuracy cannot be obtained. When DE is larger than 0.97 × DI, a desired adhesion cannot be obtained and leakage occurs.

  Further, when the thickness of the fixing portion 111 is T and the width of the fitting groove 123 is W, W is preferably 63% or more and 94% or less with respect to T, whereby the fixing portion 111 is fitted to the fitting groove 123. This is because a sufficient pressure resistance performance can be secured. T is usually selected from the range of 1.8 mm or more and 2.4 mm or less.

  In the case of the detection unit 100 disposed in a circuit used for hemodialysis, a pressure resistance performance of 0.2 MPa or more is required. The size of the diaphragm 110 is preferably 15 mm or more and 35 mm or less. This is a size that does not obstruct the configuration of the blood circuit and that can obtain sufficient detection accuracy.

  As an example, the detection unit 100 interposed in the blood circuit and other circuits used for hemodialysis has DE = 16.5 mm, DD = 22.5 mm, DO = 22.8 mm, DI = 19.7 mm. , W = 1.55 mm, T = 2.0 mm.

  In the present embodiment, the present invention has been described with specific numerical values. However, the numerical values only show numerical values that can be applied in a certain case, and do not limit the present invention. Of course, if the pressure resistance performance required for the detection unit 100 changes, the numerical value in the previous period will be different. Further, even if the size of the detection unit 100 is different, the numerical value is different.

  Moreover, although this embodiment illustrated and demonstrated the aspect which fits the fixing | fixed part 111 to the fitting groove | channel 123, this invention is not necessarily limited to this.

  For example, as shown in FIG. 12, the inner wall of the fixed portion 111 of the diaphragm 110 may come into contact with the outer wall of the inner peripheral wall 129, and the adhesion force may be secured by the contraction force of the diaphragm 110.

  Further, as shown in FIG. 13, the peripheral wall of the fixed portion 111 of the diaphragm 110 and the inner wall of the outer peripheral wall may be in contact with each other, and the adhesion force may be ensured by the expansion output of the diaphragm 110.

  The detection unit for a circuit internal pressure sensor is a detection unit used for a circuit internal pressure sensor for detecting a pressure in a liquid circuit through which a liquid flows, and is disposed in the liquid circuit and has a base having an opening; Sealing the opening and pressing it in a direction crossing the direction of the pressure to be detected, a diaphragm having an annular contact portion that is in close contact with the peripheral wall of the base, an inlet for introducing the liquid into the base, and a liquid And an outlet for leading out the substrate from the substrate.

  Thus, the diaphragm is pulled in a direction intersecting with the pressure direction to be detected, that is, a direction intersecting with the direction in which the diaphragm appears and is fitted to the peripheral wall, so that the peripheral wall is pressed in a direction different from the direction in which the fluid pressure is applied. Since the opening of the substrate is sealed, sufficient pressure resistance can be easily ensured, and the life of the diaphragm can be improved. That is, since the shielding property is provided in the direction intersecting the direction in which the fluid pressure is applied, it is not necessary to apply an excessive force to the diaphragm.

  The contact portion may be a protrusion protruding from the diaphragm main body, and the base may further include an annular fitting groove that fits into the contact portion of the protrusion on the periphery of the opening.

  Thereby, since an adhesion force can be generated by fitting the fitting groove and the protrusion, the opening can be sealed without affecting the diaphragm main body. Moreover, since the force applied to the diaphragm and the base is dispersed by using the annular fitting groove, it is possible to suppress breakage.

  Furthermore, it is preferable to provide a restricting means for restricting a shift in the pressure direction of the contact portion with respect to the base.

  According to this, since the direction of the detection pressure and the direction of the adhesion force intersect, it is possible to prevent the diaphragm from falling off completely by regulating the diaphragm that moves without being able to resist the detection pressure. It becomes possible.

  On the other hand, the above object can also be achieved by a circuit internal pressure sensor including the detection unit. Moreover, the effect is the same as the above.

  According to these, it is possible to provide a detection unit having a necessary and sufficient pressure resistance performance without strongly sandwiching the diaphragm, and it is possible to prevent the diaphragm from being damaged.

  The present invention can be applied to the blood purification apparatus and the liquid circuit body 100 used therein, and in particular to a blood purification apparatus including the disposable liquid circuit body 100.

DESCRIPTION OF SYMBOLS 100 Detection unit 110 Diaphragm 111 Fixing part 112 Contact | adhering part 113 Magnet 114 Thin part 115 Displacement part 120 Base 121 Cock 122 Opening part 123 Fitting groove 124 Cap accommodating part 125 Tubular part 126 First through hole 127 Second through hole 128 閂 129 Inner peripheral wall 130 Cap 140 Insertion jig 141 Protruding part 150 Sensor unit 151 Load cell

Claims (3)

A detection unit used for an in-circuit pressure sensor for detecting a pressure in a liquid circuit through which a liquid flows,
A substrate disposed in the liquid circuit and having an opening;
A cylindrical cap housing that surrounds the opening;
An annular fitting groove formed by the cap housing portion and a cylindrical inner peripheral wall standing integrally therewith;
A diaphragm that seals the opening, and is provided integrally with a cylindrical fixing portion that is in contact with an inner peripheral wall of the cap housing portion, and an intermediate portion in a direction of pressure detected by the fixing portion. A diaphragm having a thin annular thin-walled portion, and a disc-shaped displacement portion integrally connected to the thin-walled portion,
An inlet for introducing liquid into the substrate;
An outlet for discharging liquid from the substrate;
When the outside diameter of the fixed portion that fits into the fitting groove is DD, the inside diameter is DE, the outside diameter of the fitting groove is DO, and the inside diameter is DI,
DO ≧ DD and, to meet the DI> DE,
The detection unit for an in-circuit pressure sensor, wherein the opening is sealed in a liquid-tight state only by a force generated in a direction perpendicular to the pressure detected by the diaphragm .   The detection unit for an in-circuit pressure sensor according to claim 1, wherein 0.96 × DO ≦ DD ≦ 1.0 × DO is satisfied.   The detection unit for an in-circuit pressure sensor according to claim 1, wherein 0.96 × DI ≦ DE ≦ 0.97 × DI is satisfied.

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