JPS6026546B2 - body fluid filtration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 11. Background Technical Field of the Invention The present invention relates to a body fluid filtration device such as a filtration type artificial kidney for efficiently treating patients with renal failure.

BACKGROUND OF THE INVENTION Recently, the treatment of renal failure patients for whom dialysis is difficult has become widespread, and there is a strong demand for the development of an artificial kidney using a blood furnace for this purpose.

In blood reactor overtreatment, the amount of reactor fluid excreted outside the body is 20~
It is said that it takes 25 to 6 hours, so the artificial kidney requires 56 hours.
A furnace filtration rate of ~70'/min is required. Conventional lachrymal artificial kidneys include a hollow fiber type with multiple fibers and a stacked type with multiple flat membranes for heating. There are problems with excessive characteristics, size, manufacturing cost, etc. That is, the filtration characteristics of this type of artificial kidney largely depend on the thickness of the blood flow path, as well as the material of the filtration membrane, the blood flow rate, etc., and by making these thinner, the filtration rate can be increased.

However, with the hollow fiber type, there is a limit to reducing the inner diameter of the fiber due to manufacturing reasons.
It is about 0r. As a result, it is not only difficult to obtain the desired amount in the furnace, but also the wall shear rate decreases, and the amount in the furnace decreases over time due to proteins adhering to the wall surface, and the molecular weight fraction may also change over time. On the other hand, the conventional laminated type uses a smoother to regulate the gap (channel thickness) between the filter membranes, which makes it difficult to set the channel thickness uniformly. It is difficult to adjust the thickness to be thin, and it is surprising to improve the filtration characteristics in this product.

For this reason, we have decided to install two body fluid filtration devices of this type.
Although measures such as continuous connection or enlarging the membrane area of the device are used to obtain the appropriate amount for the furnace, there are disadvantages in this case, such as the size of the device and the high cost.

In view of these circumstances, the present applicant provided a filter membrane 2 on both sides of a mesh core material 1 to form a membrane unit 3 as an artificial kidney, as shown in FIG. We previously proposed a layered structure inside Case 4. This artificial kidney is
Each filtration membrane 2 has a wave shape that follows the uneven surface of the core material 1, and forms a body fluid (for example, blood) flow path 5 between the pus units 3, through which blood is filtered. be. However, in the above-mentioned artificial kidneys, even if they are made of the same material, shape, and size and the blood passage conditions are the same, many of them fail to obtain a predetermined furnace overflow, and there is a problem that there are many variations. Based on this, the inventor investigated the cause and found that
It has been found that because the core material is woven into a mesh, there are directions in which blood flows easily and directions in which it does not flow easily, and as a result, it is not possible to obtain a predetermined excess amount in the furnace.

In other words, in the direction along the strands that make up the core material, the blood flow path is straight and short, making it easy for a large amount of blood to flow there, whereas in the dish flow direction that forms the strand 45o, for example, the blood flow path is zigzag. This makes it difficult for blood to circulate there, and as a result, it is not possible to obtain a predetermined furnace overflow.

0 Purpose of the Invention The present invention has been made in view of the above circumstances, and its purpose is to change the flow conditions of the blood flow path in each circumferential direction by changing the direction of the strands of adjacent core materials. It is an object of the present invention to provide a body fluid filtration device which can uniformly obtain a predetermined filtration amount without variation.

Here, the dispersion means the percentage above and below the average furnace overflow that varies in the furnace overflow.

That is, in the present invention, the entire surface of the mesh-like core village in which the furnace liquid passes through the gaps in the core material is covered with a furnace filter membrane, and a furnace liquid outlet is provided at at least one location of the furnace liquid. In a body fluid filtering device in which a plurality of pus units are stacked one on top of the other and arranged in a case provided with a body fluid inlet, a furnace fluid outlet, and a body fluid outlet,
The furnace fluid outflow port of each membrane unit is communicated with the furnace fluid outflow port of the case, and any strands constituting the core village of one membrane unit and any wire constituting the core material of the other pus unit adjacent thereto The phlegm units are arranged so that the angle with the strands of the pus units is 30 to 60 degrees, and the body fluid injected from the body fluid inlet of the case passes through the body fluid flow path between the pus units and is filtered by the filter membrane. The fluid that has flowed into the phlegm unit through the filtration membrane passes through the gap between the mesh wicks, passes through the wick outlet of the phlegm unit, and flows out from the fluid outlet of the case, while the body fluid flow path This body fluid furnace filtration device is characterized in that the residual fluid passed through the furnace flows out from the body fluid outlet of the case.

Further, in the present invention, the opening of the core material is set to 700 to 1300 Buddha. Further, in the present invention, the core material has a thread diameter of 300 to 3
It is knitted with 50r strands at a ratio of 7 to 9 threads per yarn.

Further, in the present invention, the furnace membrane is mainly composed of aromatic polyamide, has a molecular weight cut-off of 20,000 to 65,000, and has a film thickness of 30 to 300.
The membrane is lined with a pus support made of nonwoven polyethylene or polypropylene fabric.

Furthermore, in the present invention, the membrane unit inside the case is pressed by an elastic member via a piston that slides into airtight contact.

Note that opening here is defined below.

o=No ab o: Opening a: Vertical length of a rectangular or square space partitioned by wires b: Horizontal length of the space m Detailed Description of the Invention The following is an artificial kidney illustrating the present invention. I will explain based on this.

Figure 2 is a cross-sectional view of the artificial kidney, and this artificial kidney is shown in Case 1.
A plurality of membrane units 12 are stacked and housed in the membrane unit 1. The case 11 is made of synthetic resin such as styrene resin and has a cylindrical shape, and has a body fluid inlet 11 such as blood at the center of the bottom.
a. A furnace liquid outlet 11b is provided on the bottom periphery, and an outlet 11c for body fluids such as blood is provided on the side. Also case 11
A piston 13 for pressing the stacked membrane units 12 is provided at the upper end of the entrance. This piston 1
3 is a ring 14, 1 made of silicone resin on the outer peripheral surface.
4, and the inner peripheral surface of the case 11 is welded airtightly. Further, an elastic member 15 imitating a compression coil is provided at the upper part of the piston 13 to press it. Further, an adjustment ring 16 is attached to the outer circumferential surface of the upper end of the case 11 to restrict upward movement of the piston 13. Therefore, each winning unit 1 accommodated in the case 11
2, as shown in FIGS. 3 and 4, a mesh core material 17
Furnace membranes 18, 18 are provided on both sides of the filter.

The core material 17 is a disk-shaped material made of woven wires made of polyester, polyethylene, or the like. This core material 17 serves as a passage through which the furnace liquid filtered by the furnace filter membrane passes.
、． 172, and if the opening of the mesh of the core material 17 is too small, the furnace overload cannot be sufficiently taken.
Also, if it is too large, it will become flexible and easily deform, and the body fluid flow path will become thick, making it difficult to form a separation of body fluids when stacked and making it impossible to obtain a predetermined appropriate amount in the furnace.
It is preferable that the In order to obtain an opening in the above range, it is suitable for production to use strands with a thread diameter of 300 to 350 mm and knit with 7 to 9 threads per thread. If the number of threads per thread exceeds 9, the furnace overload cannot be sufficiently taken, and if it is less than 7 threads, the thickness of the body fluid flow path becomes thick, forming a body fluid flow path and causing surprise, so that the furnace overload cannot be taken sufficiently.

The filter membrane 18 is made of aromatic polyamide as a main component, has a molecular weight cut-off of 20,000 to 65,000, and has a thickness of 30 to 300 membranes, and is formed by a phase separation method, an extraction method, or the like.

If the film thickness is less than 30 mm, the film strength will decrease, and if it exceeds 300 mm, the furnace overflow performance will decrease. As shown in FIG. 5, this filter membrane 18 is lined with a pus support 19 made of a nonwoven fabric of polyethylene or polypropylene. This belly support 19 increases the strength of the membrane. The membrane unit 12, in which the core membrane O 7 and the furnace membranes 18, 18 are roughly combined, has a body fluid inlet 12a at the center and a furnace fluid outlet 12b at the periphery, as shown in FIG. The peripheries of the filter membranes 18, 18 and the pus supports 19, 19 at the periphery of the body fluid inlet 12a are bonded to each other by heat bonding, ultrasonic fusion, adhesive, etc., respectively.

In the case of heat fusion, the temperature is 140 to 14 picC and the temperature is 3 to 4.
k9/It is performed using the pressure of the earth. Furthermore, the furnace liquid outlet 12
A ring-shaped sealing material 20 is adhered to the periphery of b.
This sealing material 20 is, for example, an acrylic double-sided tape with an acrylic resin coated on both sides of a base material, or a hot-melt double-sided tape with a synthetic rubber hot melt coated on both sides of the base material. This sealing material 20 closes off the blood flow path 21 between the reactor fluid outflow ports 12b of adjacent membrane units 12, and its thickness is usually 150 to 200 mm. Furthermore, the angle between the strands forming the core village 17 of the membrane unit 12 and the strands forming the core material 17 of the adjacent membrane unit 12 is set to 30 to 6 degrees.

For example, in the illustrated embodiment, one membrane unit 12 has a body fluid inlet 12a and a furnace fluid outlet 1, as shown in FIG.
The furnace liquid outlet 12b is formed such that the straight line connecting the wires 12b and 2b runs along the direction of the strands (or in a direction perpendicular to the line). On the other hand, the adjacent membrane units 122 are formed so that the straight line connecting the body fluid inlet 12a and the furnace fluid outlet 12b intersects the direction of the millet line at 45o, as shown in FIG. ,,122 The angle 8 formed by the strands of the core material 17 is 4
It is set at 5o. When the angle a is less than 300 or exceeds 600, it is difficult to obtain the desired furnace overload, and the fluctuation in the furnace overload increases. The artificial kidney thus constructed is assembled, for example, as shown in FIG. 8 to form a blood reactor overcircuit.

That is, this circuit includes a blood pump 2 and a body fluid inlet 11a.
attaching a blood inflow tube 24 with an arterial chamber 23;
A blood outflow pipe 26 equipped with a venous chamber 25 is attached to the body fluid outlet 11c, a replacement fluid supply V supply pipe 28 equipped with a replacement fluid pump 27 is attached to the venous chamber 25, and a negative pressure pump 29 is attached to the furnace fluid outlet 11b. Furnace liquid discharge pipe 30 equipped with
is installed. W. Specific operation of the invention In the blood reactor overcircuit shown in FIG. 8, bodily fluids from the human body,
For example, blood A is transferred to the blood inflow pipe 24 and the body fluid inlet 11a.
When entering the case 11 through the passageway, body fluids (for example, blood) pass through a passage 21 between the pus units 12 and are separated by the pus 18.

Blood A2 containing blood cell components after the blood* component which is the furnace fluid has been separated is returned to the human body together with replacement fluid through the body fluid outlet 11c and the blood outflow pipe 26. In addition, the furnace filtration membrane 18 of the membrane unit
The separated blood components pass through the gaps in the core materials 17, 172 and reach the furnace liquid outlet 12b of the pus unit, where the furnace liquid B filtered in each membrane unit joins and flows through the furnace liquid outlet. 116, and is discharged through the furnace liquid discharge pipe 30. V. Specific Effects of the Invention (i) The body fluid filtration device having this configuration has a uniform body fluid in each circumferential direction (e.g. blood) flow path 2
1, the desired lacrimal volume can be obtained without any variation.

In other words, when the grain lines of adjacent core materials overlap, as mentioned above, blood tends to flow in the direction along the grain lines, and it is difficult for blood to flow in the direction 450 intersecting with the grain lines.

Therefore, if the direction in which blood flows easily in one membrane unit (direction along the Qin line) and the direction in which blood in the other membrane unit does not flow easily (direction of the wire and 45o) overlap, blood will flow more easily. The thickness is uniform in all directions.
This was confirmed in the following experimental example. Experimental example 1 <Configuration of body fluid filtration device> Furnace filtration membrane: Material Aromatic polyamide membrane lined with polyethylene nonwoven fabric, outer diameter 10mm, inner diameter 1mm area 146 cm, bonding method heat seal blood data. -95% molecular weight cut off 50,000, membrane thickness 210 strand core Material: Material Polyethylene thread diameter 245 strands, number of threads 8/opening 925 mm, angle between adjacent Qin wires 30-6 dia Total area of membrane unit: 0.25-04M2 <Experimental method> Fresh bovine blood is diluted with plasma to obtain hemacrit value (Ht)2
The total protein content (T·P) was adjusted to 0% and the total protein content (T·P) was 7.0 m/d, and the furnace overload was measured by using this blood as a test solution and changing the angle formed by the lines of the adjacent core material.

The results are shown in Table 1. In addition, in order to compare with this, a case where the angle formed by the strands of the adjacent core material O is outside the scope of the present invention is used as a comparative example, and the strands completely overlap and the angle between the strands and the millet wire is 00 as a reference example, the results are also listed in Table 1. Table 1 <Experimental Results> According to the above table, in the device according to the present invention, the flow path conditions for blood flowing in the circumferential direction of the membrane unit are approximately uniform in each direction, so that a predetermined furnace overflow can be obtained. It was also confirmed that the variation in furnace overload was reduced.

(ii) Furthermore, in the present invention, by setting the opening of the core mesh to 700 to 1300 mm, an optimum furnace overload can be obtained.

This was confirmed in the following experimental examples. Experimental Example 2 A body fluid filtration device was constructed using the filtration membrane used in Experimental Example 1, with the opening of the core material varied in the range of 1572 to 660''.

Fresh bovine blood of 20 Ht and 3.0 T.P was passed through this body fluid filtration device at a flow rate of 6 to 7/min, and the filtration amount was measured.

Figure 9 shows the relationship between opening and furnace overflow. According to the measurement results shown in FIG. 9, it can be seen that the optimum furnace overflow can be obtained at 700 to 1300A.

(iii) Furthermore, in the present invention, the filter using an aromatic polyamide membrane as the filter membrane has excellent filter characteristics.

This was confirmed in the following experimental examples. Experimental Example 3 A membrane unit made of the material used in Experimental Example 1 was used to measure its molecular weight fraction.

As a result, in physiological saline solution, the inhibition rate of each indicator substance was 96-97% for bovine serum albumin and 15% for cytochrome C.
~18%, inulin 5-7%, vitamin B2 0-2
%, BUN is 0%, and the molecular weight cutoff is MW50,00.
It was 0 to 60,000. In addition, Ht25%, T・P
3.5 In fresh bovine blood, the inhibition rate of each indicator substance is:
Bovine serum - albumin ~100%, cytochrome C 60~65%, inulin 30~35%, vitamin B8
2-5% for BUN, 0% for BUN, and the molecular weight cutoff is MW4.
It was 0000-50000. From these results, it can be seen that the aromatic polyamide membrane is suitable for blood filtration because almost no albumin (MW 69,000) passes through it, and many substances with a molecular weight lower than that pass through it.

Further, according to the present invention, since each furnace membrane is lined with a membrane support made of a nonwoven fabric of polyethylene or polypropylene, the membranes can be sealed with this support, and the furnace membranes can be mutually sealed. It is easy and reliable to seal, and has excellent workability.

In addition, in the present invention, the pressure force applied to the furnace filtration membrane can be arbitrarily adjusted using the piston equipped with the O-ring, so by adjusting this pressure force, the blood flow separation thickness can be made as small as possible, and the furnace excess amount can be increased. be able to.

Furthermore, the piston is an elastic member 1 which is a compression coil spring.
5, the thickness of the blood flow path changes according to the pulsation of blood flowing into the device, resulting in excellent safety. Brief explanation of the drawings - Figure 1 is a sectional view of the main parts of the artificial kidney presented earlier, Figure 2 is a sectional view of the artificial kidney, Figure 3 is a sectional view of the membrane unit, and Figure 4 is a sectional view of the membrane unit.
5 is a partially enlarged view of FIG. 3, FIGS. 6 and 7 are partially cutaway plan views showing two types of membrane units according to the present invention, and FIG. 8 is a plan view of the membrane unit. FIG. 2 is an explanatory diagram of a furnace overflow circuit incorporating an artificial kidney, and FIG. 9 is a characteristic diagram showing the relationship between opening and furnace overflow.

11...Case, 12...Waist unit, 12a...
Body fluid inlet, 12b... Furnace fluid outlet, 11a.
... Body fluid inlet, 11b ... Furnace liquid outlet,
11c... Body fluid outlet, 13... Piston, 14...○ ring, 15... Elastic member, 16... Adjustment ring, 17. ... Core material, 18 ... Furnace filtration membrane, 19 ... Membrane support, 20 ... Seal material, 21 ... Blood flow path , 22... Blood pump, 23... Arterial chamber, 24... Blood inflow pipe, 25... Venous chamber, 26... Blood outflow pipe, 27...
... Replacement fluid pump, 28 ... Replacement fluid supply pipe, 2
9... Negative pressure pump, 30... Furnace liquid discharge pipe.

Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 figure 〇 ship,

Claims (1)

[Scope of Claims] 1. A membrane unit in which the entire surface of a mesh-like core material that allows filtrate to pass through gaps within the core material is covered with a filtration membrane, and a filtrate outlet is provided at at least one location on the filtration membrane. In a body fluid filtration device in which a plurality of membrane units are stacked one on top of the other and arranged in a case provided with a body fluid inlet, a filtrate outlet, and a body fluid outlet, the filtrate outlet of each membrane unit is communicated with the filtrate outlet of the case. , and the membrane unit is arranged so that an angle between an arbitrary strand constituting the core material of one membrane unit and an arbitrary strand constituting the core material of the other membrane unit adjacent thereto is 30 to 60°. The body fluid flowing in from the body fluid inlet of the case described above passes through the body fluid flow path between the membrane units, is filtered by the filtration membrane, and the filtrate that flows into the membrane unit via the filtration membrane passes through the mesh core. The filtrate passes through the gap between the materials, passes through the filtrate outlet of the membrane unit, and flows out of the filtrate outlet of the case, while the residual filtrate that has passed through the body fluid channel flows out of the body fluid outlet of the case. Characteristic body fluid filtration device. 2. The body fluid filtration device according to claim 1, wherein the opening of the core material is 700 to 1300μ. 3. The core material is made by knitting wires with a thread diameter of 300 to 350μ at a ratio of 7 to 9 threads per cm.
The body fluid filtration device according to item 1 or 2. 4. The filtration membrane is made of aromatic polyamide as a main component, has a molecular weight cut-off of 20,000 to 65,000, and has a thickness of 30 to 300μ, and is lined with a membrane support made of a nonwoven fabric of polyethylene or polypropylene. The body fluid filtration device according to item 1. 5. The membrane unit in the case is pressed by an elastic member via a piston that slides in airtight contact.
Body fluid filtration device as described in section.