JP3270193B2 - Filtration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter, and more particularly to a filter for separating and removing air bubbles and foreign matters from blood.

[0002]

2. Description of the Related Art For example, in a blood extracorporeal circuit for processing blood removed from a patient and returning the blood to the patient again,
A filtration device (blood filter) for separating and removing air bubbles and foreign substances in blood is installed in the blood return line.

[0003] This filtration device is generally called a blood filter or a bubble trap, and uses a pleated filter medium to obtain a large filtration area, for example, as disclosed in JP-A-1-148265 and JP-A-1-148266. Japanese Unexamined Patent Application Publication No. 2000-163,086 is known.

Of these, for example, Japanese Patent Application Laid-Open No. 1-1482
The conventional blood filter (1) described in Japanese Patent Application Publication No. 65-165 has a housing, and a plurality of pleats of a porous material folded in a plurality of pleats are provided in a blood filtering portion (3) at a lower portion of the housing. The filter medium (10) formed into a cylindrical shape so as to be arranged radially is housed. The upper end opening of the filter medium (10) is sealed by an impermeable portion (10a) obtained by injecting and solidifying a potting material, and a blood outlet (9) formed at the lower end of the housing.
Communicates with the space inside the filter medium (10).

However, this blood filter (1)
Is the opaque part (10a) that seals the top opening of the filter medium (10)
Since the surface inside the filter medium is flat and horizontal, the following problems occur.

That is, during priming of the blood filter (1), the priming liquid is filled into the space inside the filter medium (10) from the blood outlet (9). At this time, air bubbles contained in the priming liquid are particularly damaged. It is easy to stay inside the pleat valley (outer side of the pleat) in the space, and the air bubble elimination property is poor.

In the treatment of blood, air bubbles which cannot be completely removed in the air bubble separating section (2) and reach the outer peripheral side of the filter medium (10) are particularly deep inside the valleys of the pleats (inner side of the pleats). Easy to stay and hard to remove.

[0008] The ability of the blood filter to remove air bubbles can be improved by devising the structure of the upper portion of the housing or increasing the length of the filter medium in the axial direction. The priming amount of blood in the filter increases, which is not preferable.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a filtration apparatus capable of improving the ability to remove air bubbles during priming or liquid processing.

[0010]

This and other objects are achieved by the present invention which is defined below as (1) to (5).

(1) A housing having an inlet, an outlet, and a deaeration port for a liquid to be treated, a first space communicating with the inlet in the housing, and a second space communicating with the outlet. A filter member installed in the housing so as to partition the filter member into a space, wherein the filter member has a plurality of pleats of a porous material folded in a plurality of pleats arranged radially. Is formed in a cylindrical shape, and the top side opening thereof is sealed with a filler, and the surface of the filler on the second space side has a center portion toward the second space side. A filtration device characterized by a tapered surface that is inclined so as to protrude and that forms a continuous surface that is continuous from the center to the outer periphery.

(2) The filtering device according to (1), wherein the outermost diameter of the filtering member gradually increases from a top to a bottom.

(3) The filtering device according to (2), wherein the filtering member is obtained by sealing a top opening of the filtering member with a filler and then expanding a bottom portion of the filtering member.

(4) The filtering device according to any one of (1) to (3), wherein the housing has a substantially circular cross-sectional shape, and the filtering member is installed concentrically with the housing. .

(5) The inlet is formed so as to project substantially tangentially to the inner peripheral surface of the housing, and the liquid flowing from the inlet forms a swirling flow in the first space. The filtration device according to the above (4).

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a preferred embodiment of the present invention.

FIG. 1 is a longitudinal sectional view showing an example of a configuration in which the filtration device of the present invention is applied to a filtration device installed in a blood extracorporeal circuit. FIG. 2 is a sectional view taken along line II-II in FIG. It is sectional drawing.

As shown in these figures, the filtration device 1 of the present invention has a housing 2 composed of a bottom 3 and a lid 4. The bottom 3 and the lid 4 are connected to a filtering member 6 described later.
After being stored, they are joined by, for example, screw fitting as described in JP-A-62-84772, and the fitting portion is sealed in a liquid-tight manner with a filler 9 described later.

The housing 2 has a shape of a rotating body about a shaft 23, that is, as shown in FIG. 2, its cross-sectional shape is substantially circular. On the outer peripheral surface of the lid 4 of the housing 2, an inflow port 51 for blood, which is a liquid to be treated, is formed. The inflow port 51 is formed so as to protrude substantially in a tangential direction on the inner peripheral surface of the lid 4. Thereby, the blood flowing into the housing 2 from the inflow port 51 is
A swirling flow that flows in one direction along the inner peripheral surface of the lid 4 is formed.

The upper part in FIG. 1 of the lid 4 of the housing 2 has a conical shape or a funnel shape in which the outer diameter and the inner diameter gradually decrease upward, and the tip thereof is separated and removed from the blood. A deaeration port 53 for discharging air bubbles is formed to protrude. Although not shown, a valve such as a three-way cock is connected to the deaeration port 53 and used.

At the center of the bottom 3 of the housing 2 is formed a funnel-shaped blood outflow portion 31 whose outer diameter and inner diameter gradually decrease downward in FIG. Has a blood outlet 52 protruding therefrom.

The outlet 52 and the deaeration 53
Is preferably formed on the central axis 23 of the housing 2.

On the outer peripheral side of the blood outflow portion 31 of the bottom body 3,
A filter member fixing portion 32 for fixing a filter member 6 described later is formed, and the filter member fixing portion 32 and the blood outflow portion 3 are fixed.
A ring-shaped rib 33 projecting inward from the housing 2 is formed at a boundary with the housing 1. The rib 33 functions as a dam that locks the tip of the pleat 7 protruding inside the filtering member 6 and that prevents the filler 9 injected into the filtering member fixing portion 32 from flowing out to the blood outflow portion 31 side. To fulfill.

The bottom 3 and lid 4 of the housing 2 may be made of, for example, polycarbonate, acrylic resin, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acryl-styrene copolymer, acryl-butadiene- Styrene copolymers and the like can be mentioned, and it is preferably transparent or translucent to secure the internal visibility.

In the housing 2, a filtering member 6 for filtering air bubbles and foreign substances mixed in blood is housed and installed. Due to the filtering member 6, the first space 21 formed outside the filtering member 6 and the filtering member 6 are formed inside the housing 2.
And a second space 22 formed inside. The inflow port 51 and the deaeration port 53 communicate with the first space 21, and the outflow port 52 communicates with the second space 22.

Hereinafter, the configuration of the filtering member 6 will be described in detail. The filtering member 6 is formed in a tubular shape so that a plurality of pleats (folds) 7 of a porous material folded in a pleated shape are radially arranged, and the top opening is a filler 8.
It is sealed by the following.

In this embodiment, the filtering member 6 has a configuration in which the outermost diameter gradually increases from the top to the bottom, that is, has a hollow truncated cone shape. By forming the filtering member 6 in such a shape, the inflow of blood into the first space 21 and the formation of a swirling flow in the first space 21 are smoothly performed without increasing the volume of the housing 2, that is, the priming amount. Done well. As a result, the efficiency of separating and removing the bubbles is increased, and the pressure loss can be reduced and the hemolysis can be suppressed.

The porous material constituting each pleat 7 of the filtering member 6 may be any material such as a mesh, a net, a foam, a woven fabric, a non-woven fabric, or a combination thereof as appropriate. A screen mesh made of polyester in which both sides are sandwiched between polypropylene or polyester nets may be used. The minimum pore size (opening) of a porous material represented by such a mesh or a net is 20 to 200 μm.
m, especially about 20 to 60 μm are preferably used.

The present invention is characterized by the shape of the filler 8 that seals the top opening of the filter member 6. That is, FIG.
As shown in FIG. 5, the surface of the filler 8 on the side of the second space 22 (hereinafter referred to as the “lower surface 81”) has a central portion 82 projecting toward the second space 22 and the filler 8 from the central portion 82. A part reaching the outer periphery, particularly a pleat crossing portion 83 crossing each pleat 7 is inclined at a predetermined angle with respect to the horizontal (horizontal direction in FIG. 1).

By forming the lower surface 81 of the filler 8 in such a shape, the second space 22 during priming is formed.
This improves the removability of air bubbles inside and the removability of air bubbles that have entered the valleys 72 of each pleat 7 during blood processing.

The inclination angle of the lower surface 81 with respect to the horizontal in the pleated cross section 83 is not particularly limited.
It is preferable to set it to about 0 to 60 °.

The constituent material of the filler 8 includes, for example, polyurethane, silicone, epoxy resin, polyethylene, polypropylene, polyolefin such as ethylene-vinyl acetate copolymer, and polymer materials such as various rubber materials. Among them, polyurethane, silicone, and epoxy resin are particularly preferable.

The conditions such as the size of the filtering member 6 are not particularly limited, but examples of suitable ranges include those shown in Table 1 below.

[0034]

[Table 1]

Such a filtering member 6 can be manufactured, for example, by the following method.

First, the pleated folded porous material is formed into a cylindrical shape such that the respective pleats are arranged radially, and then the filler 8 is injected into the top side. At this time, the lower surface 81 of the filler may be horizontal.

Before the filling material 8 is completely cured, for example, a mold material is inserted and the bottom side of the filtering member 6 is expanded. Thus, the filtering member 6 has a truncated cone shape, and the lower surface 81 of the filler 8 has the shape described above. In this state, the filler 8 is cured, and the mold is removed to complete the filter member 6 as shown.

According to such a manufacturing method, the filtering member 6
And the shape of the lower surface 81 of the filler 8 can be easily obtained, and the reproducibility when mass-produced is excellent.

To fix the filter member 6 to the housing 2, the filler 9 is poured into the filter member fixing portion 32 of the bottom body 3, and then the bottom of the filter member 6 is positioned at the filter member fixing portion 32 to fill the filler 9. This is performed by hardening the filler 9 in a state where the pleats protruding inward of the filter member 6 are engaged with the ribs 33 while being immersed in the filter member 6. In this case, it is preferable that the central axis of the filter member 6 is fixed so as to coincide with or approach the axis 23 of the housing 2. In addition, as the filler 9, the same material as the filler 8 can be used.

The filtering device 1 of the present invention is installed in a blood extracorporeal circuit 10 as shown in FIG. The extracorporeal blood circulation circuit 10 includes a blood reservoir 11, a roller pump 12, a heat exchanger 13, an artificial lung 14, a filtration device 1, and a patient 20.
A tube 15 connecting the vein of the blood reservoir 11 and the tube 16 connecting the blood reservoir 11 and the roller pump 12
A tube 17 connecting the roller pump 12 and the heat exchanger 13; a tube 18 connecting the blood outlet of the oxygenator 14 and the inlet 51 of the filtration device 1; an outlet 52 of the filtration device 1; And a tube 19 connecting the arteries 20.

When performing the priming operation and the blood treatment by extracorporeal blood circulation, the filtration device 1 is fixed in a posture such that the shaft 23 is in the vertical direction.

Next, the operation of the filtration device 1 will be described.

[Priming Operation] A priming solution such as a physiological saline solution is injected into the casing 2 from the outlet 52 through the tube 19. In this priming liquid, fine bubbles may be mixed,
The air bubbles float in the second space 22 and first reach the lower surface 81 of the filler 8. At this time, the lower surface 81
As described above, since the central portion 82 projects downward and inclines upward toward the outer periphery, the air bubbles float along this inclined surface and reach the inside 71 of the ridge of the pleat 7. Due to the pressure difference between the second space 22 and the first space 21, the water flows through the pores of the filtering member 6 and flows into the first space 21. The air bubbles flowing into the first space 21 further cover the lid 4.
And is discharged out of the casing 2 through the deaeration port 53.

As described above, since no air bubbles remain near the lower surface 81 of the filler 8, the air-bleeding property at the time of priming is greatly improved. Moreover, it is not necessary to increase the capacity or change the shape of the housing 2 in order to obtain such excellent air bubble elimination properties, and the priming amount is not increased.

[During Blood Processing] The blood removed from the vein of the patient 20 is temporarily stored in the blood storage tank 11 via the tube 15, and the blood in the blood storage tank 11 is further transferred to the roller pump 1.
By the operation of 2, after being sent to the heat exchanger 13 via the tubes 16 and 17 to be cooled or heated and then oxygenated and decarbonated by the oxygenator 14, the tube 1
8, is supplied to the inflow port 51 of the filtration device 1.

The blood introduced from the inlet 51 into the first space 21 in the casing 2 forms a swirling flow in the first space 21. When air bubbles are mixed in the blood, the air bubbles rise above the lid 4 due to buoyancy while swirling, and bubbles having a small mass gather at the center of the swirling flow due to centrifugal force. It floats along the upper inner surface of the body 4 and is discharged from the casing 2 through the deaeration port 53.

At this time, air bubbles that cannot be completely separated may enter the valleys 72 of the pleats 7 (the gaps between the adjacent pleats 7). In the deep part of the valley 72, the air bubbles float and adhere to the lower surface 81 of the pleated cross section 83 of the filler 8. However, since the lower surface 81 is inclined as described above, the air bubbles are formed along the inclined surface. Since it floats up and escapes from the inside of the valley 72, it is prevented that air bubbles remain in the valley 72.

The blood from which the air bubbles have been separated and removed in this manner passes through the innumerable pores of the filter member 6 and passes through the second space 22.
Flows into At this time, foreign substances mixed into the blood cannot pass through the pores of the filtering member 6 and are filtered off.

At this time, fine bubbles are generated in the filtering member 6.
May flow into the second space 22 through the fine pores, but the air bubbles float in the second space 22 and reach the lower surface 81 of the filler 8 as in the case of the priming, It floats along the inclined lower surface 81 and moves to the inner side 71 of the ridge of the pleat 7, and a part of it further returns to the first space 21 through the pores of the filtering member 6, and floats to discharge Is done.

The filtered blood that has flowed into the second space 22 flows out of the casing 2 from the outlet 52 through the blood outlet 31, and is returned to the artery of the patient 20 via the tube 19.

As described above, the air bubbles that have entered the valleys 72 and the inner ridges 71 of the pleats 7 are effectively discharged.
The efficiency of removing air bubbles from blood is greatly improved. Moreover,
In order to obtain such excellent air bubble removal capability, the housing 2
It is not necessary to increase the capacity or change the shape of the conventional device, and the priming amount is not increased.

The filtering device of the present invention is shown in FIGS.
The present invention is not limited to the case where the present invention is applied to a filtration device that filters blood and removes bubbles as shown in FIG.

In the present invention, the liquid to be treated is
The body is not limited to the blood, and may be any other body fluid such as plasma or a liquid other than body fluid.

Next, the filtration device of the present invention will be described in more detail with reference to specific examples.

(Example 1) A filter having the structure shown in FIGS. 1 and 2 was manufactured. The filtration member was manufactured by the above-described manufacturing method. The conditions of each part of this filtration device are as follows.

Housing material: Polycarbonate Inner diameter of inlet: 6.0 mm Inner diameter of outlet: 6.0 mm Inner diameter of deaeration port: 4.3 mm Structure of porous material: Polyester screen mesh (pore diameter 32 μm) on both sides of polypropylene Thickness of porous material: 1.0 mm Bottom outer diameter of filter member: 60 mm Top outer diameter of filter member: 34 mm Bottom inner diameter of filter member: 44 mm Top inner diameter of filter member: 18 mm Filter member height: 22 mm Number of pleats: 30 Filtering member effective area: 200 cm ² Filler composition: Polyurethane Filler bottom surface (crossed pleats) Average inclination angle: 15 ° to the horizontal Priming amount: 40 ml

(Comparative Example 1) A filter device similar to that of Example 1 was manufactured except that the structure of the filtration member was changed as follows.

Structure of porous material: Same as in Example 1 Thickness of porous material: Same as in Example 1 Bottom outer diameter of filtration member: 47 mm Top outer diameter of filtration member: 47 mm Bottom inner diameter of filtration member: 31 mm Filtration Inner top diameter of member: 31 mm Height of filter member: Same as in Example 1 Number of pleats: Same as in Example 1 Effective area of filter member: Same as in Example 1 Composition of filler: Same as in Example 1 Lower surface of filler: Horizontal priming volume: 41 ml (almost the same as in Example 1)

(Comparative Example 2) A filter device similar to that of Example 1 was manufactured except that the configuration of the filter member was as follows, and the casing capacity was increased with the increase in size of the filter member.

Structure of porous material: Same as in Example 1 Thickness of porous material: Same as in Example 1 Bottom outer diameter of filter member: 60 mm Top outer diameter of filter member: 60 mm Bottom inner diameter of filter member: 44 mm Filtration Top inner diameter of member: 44 mm Height of filter member: 42 mm Number of pleats: same as in Example 1 Effective area of filter member: 400 cm ² (2.0 times of Example 1) Composition of filler: same as in Example 1 Filler bottom surface: horizontal Priming volume: 110 ml (2.75 times that of Example 1)

Using the respective filtration devices of Example 1 and Comparative Examples 1 and 2, the following priming experiments were performed.

[Experiment 1] A priming solution containing fine bubbles was injected from the outlet of each of the filtration devices of Example 1, Comparative Examples 1 and 2, and the inside of the housing was filled with a priming solution (physiological saline). In this state, the state of attachment of air bubbles to the filtration member was visually observed to evaluate air bubble removal.

In the filtration device of Example 1, a very small amount of air bubbles adhered to the vicinity of the top of the filtration member, but could be easily removed by applying a slight vibration.

In each of the filtration devices of Comparative Examples 1 and 2, a large amount of air bubbles was observed near the top of the filtration member, particularly inside the ridges (inside the filtration member) of each pleat.

From the above, it was confirmed that the filtration device of Example 1 was superior to the filtration devices of Comparative Examples 1 and 2 in removing bubbles during priming.

Next, using the filtration devices of Example 1 and Comparative Examples 1 and 2, the following experiments regarding blood treatment were performed.

[Experiment 2] 37 ° C. from the inlet to each of the filtration devices (primed) of Example 1, Comparative Examples 1 and 2.
While supplying cattle blood (Ht = 34.2%) at a flow rate of 2500 ml / min, 10 ml of air was injected into the blood supply line using a syringe (air shot). Then, the maximum diameter of bubbles existing in the blood flowing out from the outlet of each filtration device was measured. The results are shown in Table 2 below.

[0068]

[Table 2]

As shown in Table 2, it was confirmed that the filtering device of Example 1 had a small maximum diameter of the bubbles flowing out from the outlet, and thus had excellent bubble removing ability.

On the other hand, the filtering device of Comparative Example 2 is slightly inferior to the filtering device of Example 1 in the ability to remove bubbles, but the priming amount is significantly increased. Comparative Example 1
Although the priming amount is the same as that of the filtering device of Example 1, the filtering device of No. 1 is inferior in bubble removing ability.

[0071]

As described above, according to the filtering apparatus of the present invention, the bubble removing ability can be improved without increasing the amount of priming, for example, during priming or liquid processing.

When the outermost diameter of the filter member is gradually increased from the top to the bottom, it is particularly advantageous for reducing the amount of priming, and the state of flow in the first space can be improved. Since it can be maintained, the ability to separate and remove bubbles can be further enhanced, and the pressure loss can be reduced and hemolysis can be suppressed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration example of a filtration device of the present invention.

FIG. 2 is a sectional view taken along line II-II of the filtration device shown in FIG.

FIG. 3 is a circuit diagram schematically showing an extracorporeal blood circulation circuit including the filtration device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Housing 21 1st space 22 2nd space 23 Axis 3 Bottom body 4 Lid body 51 Inflow port 52 Outflow port 53 Deaeration port 6 Filtering member 7 Pleat 71 Inside mountain part 72 Valley part 8 Filler 81 Lower surface 82 Central part 83 Pleat crossing part 9 Filling material 10 Extracorporeal blood circulation circuit 11 Blood reservoir 12 Roller pump 13 Heat exchanger 14 Artificial lung 15, 16, 17, 18, 19 Tube 20 Patient

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61M 1/22 510 A61M 1/36 520

Claims (5)

(57) [Claims] 1. A housing having an inlet, an outlet, and a deaeration port for a liquid to be processed, a first space communicating with the inlet in the housing, and a second space communicating with the outlet. A filter member provided in the housing so as to partition the filter member into a space, wherein the filter member has a plurality of pleats of a porous material folded in a plurality of pleats arranged radially. And the top side opening thereof is sealed with a filler, and the surface of the filler on the second space side has a center part protruding toward the second space side. A filtration surface characterized by a tapered surface inclined so as to form a continuous surface extending from the center to the outer periphery thereof. 2. The filtering device according to claim 1, wherein the outermost diameter of the filtering member gradually increases from a top to a bottom. 3. The filtering device according to claim 2, wherein the filtering member is obtained by sealing a top opening of the filtering member with a filler and then expanding a bottom portion of the filtering member. 4. The filtering device according to claim 1, wherein the housing has a substantially circular cross section, and the filtering member is provided concentrically with the housing. 5. The inflow port is formed so as to protrude substantially tangentially to an inner peripheral surface of the housing, and a liquid flowing from the inflow port forms a swirling flow in the first space. Item 5. The filtration device according to Item 4.