JPH06312015A - Filter - Google Patents

Abstract

PURPOSE:To improve bubble removability without increasing a priming amount. CONSTITUTION:A filter 1 has a housing 2 formed projectingly with an inflow port 51, an outflow port 52 and a dearating port 53 and provided therein with a filter member 6 to partition the housing into a first space 21 and second space 22. The filter member 6 is molded into a hollow bed having a plurality of porous pleats 7 installed radially and folded like pleats and has the top side opening sealed by a filling material 8. The lower surface 81 of the filling material 8 has the center part projecting to a second space 22 side, and a pleat crossing part located therearound is inclined by a predetermined angle to the horizontal.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art For example, in a blood extracorporeal circuit for treating blood removed from a patient and returning it to the patient again,
A filtering device (blood filter) that separates and removes air bubbles and foreign substances in blood is installed on the blood returning line.

This filtering device is generally called a blood filter or a bubble trap, and as a device using a pleated filter material to obtain a wide filtering area, for example, JP-A-1-148265 and JP-A-1-148266. Those described in Japanese Patent Publications and the like are known.

Among these, for example, Japanese Unexamined Patent Publication No. 1-1482.
The conventional blood filter (1) described in Japanese Patent Laid-Open No. 65 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 material (10) is formed in a cylindrical shape so as to be radially arranged. The upper end opening of the filter medium (10) is sealed by the impermeable part (10a) obtained by injecting and solidifying the potting material, and the blood outlet (9) formed at the lower end of the housing.
Communicate with the space inside the filter medium (10).

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

That is, at the time of priming the blood filter (1), the priming liquid is filled from the blood outlet (9) into the space inside the filter medium (10). At this time, bubbles contained in the priming liquid are In the space, it is easy to stay in the deep part of the trough of the pleat (outer peripheral side of the pleat), and the bubble escape property is poor.

Further, during the processing of blood, the bubbles that cannot be completely removed in the bubble separating part (2) and have reached the outer peripheral side of the filter medium (10) are particularly deep inside the troughs of the pleats (inner peripheral side of the pleats). It easily stays and is difficult to remove.

The air bubble removing ability of the blood filter can be improved by devising the structure of the upper portion of the housing or increasing the axial length of the filter medium. 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 filter device capable of improving bubble removing ability during priming and liquid treatment.

[0010]

Such an object is achieved by the present invention (1) described below. Also, the following (2)-
It is preferably (5).

(1) A housing having an inflow port, an outflow port, and a degassing port for a liquid to be treated, a first space communicating with the inflow port and a second space communicating with the outflow port in the housing. And a filtering member installed in the housing so as to be partitioned into a space and the pleats of the porous material folded into a plurality of pleats are radially arranged in the filtering member. Is shaped like a cylinder, and its top side opening is sealed with a filler, and the surface of the filler on the side of the second space has a center portion thereof toward the side of the second space. A filtering device that is inclined so as to project.

(2) The filtration device according to (1), wherein the filtration member has an outermost diameter that gradually increases from the top to the bottom.

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

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

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The filtration device of the present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a vertical cross-sectional view showing a structural example when the filtering device of the present invention is applied to a filtering device installed in a blood extracorporeal circulation circuit, and FIG. 2 is a line II-II in FIG. FIG.

As shown in these figures, the filtering device 1 of the present invention has a housing 2 composed of a bottom body 3 and a lid body 4. The bottom body 3 and the lid body 4 are the filtration members 6 to be described later.
After they are housed, they are joined by screw fitting as described in, for example, Japanese Patent Laid-Open No. 62-84772, and the fitting portion is liquid-tightly sealed with a filling material 9 described later.

The housing 2 has a shape of a rotary body around the shaft 23, that is, as shown in FIG. 2, its cross section has a substantially circular shape. An inflow port 51 for blood, which is a liquid to be treated, is formed on the outer peripheral surface of the lid body 4 of the housing 2. The inflow port 51 is formed so as to project substantially in the tangential direction on the inner peripheral surface of the lid 4. As a result, the blood flowing into the housing 2 through the inflow port 51 is
A swirling flow that flows in one direction is formed along the inner peripheral surface of the lid body 41.

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

At the center of the bottom body 3 of the housing 2, there is formed a funnel-shaped blood outflow portion 31 whose outer diameter and inner diameter are gradually reduced downward in FIG. 1, and the tip of this blood outflow portion 31 is formed. A blood outlet 52 is formed in a protruding manner.

The outflow port 52 and the degassing port 53 are also provided.
Are 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 filtration member fixing portion 32 for fixing a filtration member 6 described later is formed, and the filtration member fixing portion 32 and the blood outflow portion 3 are formed.
A ring-shaped rib 33 that protrudes inward of the housing 2 is formed at a boundary portion with the housing 1. The rib 33 serves as a dam that locks the tip of the pleat 7 that protrudes inward of 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.

Examples of the constituent material of the bottom body 3 and the lid body 4 of the housing 2 include polycarbonate, acrylic resin, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acryl-styrene copolymer, acryl-butadiene-. Examples thereof include styrene copolymers, which are preferably transparent or translucent in order to secure the internal visibility.

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

The structure of the filter member 6 will be described in detail below. The filter member 6 is formed in a tubular shape so that the pleats (folds) 7 of the porous material folded into a plurality of pleats are radially arranged, and the top side opening thereof is the filler 8.
It has been sealed by.

In the case of the present embodiment, the filter member 6 has a configuration in which the outermost diameter thereof gradually increases from the top to the bottom, that is, a hollow truncated cone shape. The filter member 6 having such a shape facilitates the inflow of blood into the first space 21 and the formation of the swirling flow in the first space 21 without increasing the volume of the housing 2, that is, the priming amount. Well done. As a result, the efficiency of air bubble separation and removal can be increased, and the pressure loss can be reduced and hemolysis can be suppressed.

The porous material forming each pleat 7 of the filtering member 6 may be any material such as mesh, net, foam, woven fabric, non-woven fabric or a combination thereof, for example, polypropylene or An example is a screen mesh made of polyester sandwiched between nets made of polypropylene or polyester. In addition, the minimum pore diameter (opening) of the porous material typified by such a mesh or net is 20 to 200 μm.
Those having a size of about m, particularly 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. 7, the surface of the filling material 8 on the second space 22 side (hereinafter, referred to as “lower surface 81”) has a central portion 82 protruding toward the second space 22 side, and the filling material 8 extends from the central portion 82. A portion extending to the outer periphery of the pleats, in particular, a pleat crossing portion 83 that crosses 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 filling material 8 into such a shape, the second space 22 during priming is obtained.
The ability to escape bubbles inside and the ability to remove bubbles that have entered the valleys 72 of each pleat 7 during blood processing are improved.

The inclination angle of the lower surface 81 with respect to the horizontal in the pleat crossing portion 83 is not particularly limited, but in order to exert the above effect more effectively, it is 5 ° or more on average, and particularly 1 °.
The angle is preferably about 0 to 60 °.

Examples of the constituent material of the filler 8 include high molecular materials such as polyurethane, silicone, epoxy resin, polyethylene, polypropylene, polyolefin such as ethylene-vinyl acetate copolymer, and various rubber materials. Among them, polyurethane, silicone, and epoxy resin are particularly preferable.

The conditions such as the size of the filter member 6 are not particularly limited, but as an example of a suitable range, those shown in Table 1 below can be mentioned.

[0034]

[Table 1]

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

First, a porous material folded into pleats is formed into a cylindrical shape so that the pleats are radially arranged, and then the filler 8 is poured on the top side thereof. At this time, the lower surface 81 of the filling material may be horizontal.

Before the filling material 8 is completely hardened, for example, a mold material is inserted to expand the bottom side of the filtering member 6. As a result, the filter member 6 has a truncated cone shape, and the lower surface 81 of the filling material 8 has the shape described above. In this state, the filler 8 is hardened, the mold material is removed, and the filter member 6 as shown in the figure is completed.

According to such a manufacturing method, the filtering member 6
The truncated cone shape and the shape of the lower surface 81 of the filling material 8 can be easily obtained, and the reproducibility in mass production is excellent.

The fixing of the filter member 6 to the housing 2 is performed by injecting the filler 9 into the filter member fixing portion 32 of the bottom body 3 and then positioning the bottom portion of the filter member 6 to the filter member fixing portion 32. It is performed by hardening the filling material 9 in a state where the pleat projecting inward of the filtering member 6 is immersed in the rib 33 and is locked to the rib 33. In this case, it is preferable that the central axis of the filter member 6 is fixed to the shaft 23 of the housing 2 so as to match or approach. As the filler 9, the same filler as the filler 8 can be used.

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

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

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

[During Priming Operation] A priming liquid such as physiological saline is injected into the casing 2 from the outlet 52 through the tube 19. Micro bubbles may be mixed in this priming liquid,
The bubbles float in the second space 22 and first reach the lower surface 81 of the filling material 8. At this time, the lower surface 81 is
As described above, since the central portion 82 projects downward and is inclined upward toward the outer periphery, the bubbles float along the inclined surface and reach the inside 71 of the mountain portion of the pleat 7, and further, Due to the pressure difference between the second space 22 and the first space 21, it permeates the pores of the filtering member 6 and flows into the first space 21. The bubbles that have flowed into the first space 21 are further covered by the lid 4
And is discharged to the outside of the casing 2 through the deaeration port 53.

Since no bubbles remain in the vicinity of the lower surface 81 of the filling material 8 in this manner, the bubble removal property during priming is greatly improved. Moreover, in order to obtain such excellent air bubble removal property, it is not necessary to make the housing 2 larger in capacity or change the shape thereof than the conventional one, and the priming amount is not increased.

[At the time of blood processing] The blood removed from the vein of the patient 20 is temporarily stored in the blood reservoir 11 via the tube 15, and the blood in the blood reservoir 11 is further transferred to the roller pump 1.
2 is sent to the heat exchanger 13 via the tubes 16 and 17 to be cooled or heated, and then oxygenated and decarbonated in the oxygenator 14, and then the tube 1
It is supplied to the inflow port 51 of the filtration device 1 via 8.

The blood introduced from the inflow port 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 float above the lid 4 due to buoyancy while swirling, and due to the centrifugal force, air bubbles having a small mass gather at the center of the swirling flow, and further the lid is closed. It floats along the inner surface of the upper part of the body 4 and is discharged to the outside of the casing 2 through the deaeration port 53.

At this time, bubbles that have not been completely separated may intrude into the troughs 72 of the pleats 7 (the gaps between the adjacent pleats 7). In the deep part of the valley part 72, the bubbles float and adhere to the lower surface 81 of the pleats crossing part 83 of the filling material 8. However, since the lower surface 81 is inclined as described above, the bubbles are formed along the inclined surface. Since it floats up and escapes from the inside of the valley 72, it is possible to prevent bubbles from remaining in the valley 72.

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

At this time, minute air bubbles are generated in the filtering member 6.
May pass through the pores of the second space 22 and flow into the second space 22. However, the bubbles float in the second space 22 and reach the lower surface 81 of the filler 8 as in the priming, It floats up along the inclined lower surface 81 and moves to the inside 71 of the mountain portion of the pleat 7, and a part of it passes through the pores of the filtration member 6 and is returned to the first space 21, and floats and is discharged. To be done.

The filtered blood flowing into the second space 22 flows out of the casing 2 through the blood outlet 31 through the blood outlet 31, and is returned to the artery of the patient 20 through the tube 19.

As described above, the bubbles that have entered the valleys 72 and the insides 71 of the pleats 7 are effectively discharged,
The efficiency of removing bubbles from the blood is greatly improved. Moreover,
In order to obtain such excellent air bubble removing ability, the housing 2
There is no need to make the capacity larger or change the shape than the conventional one, and the priming amount does not increase.

The filtering device of the present invention is shown in FIGS.
The application is not limited to the case where it is applied to a filtration device for filtering and defoaming blood as shown in (1), and the application may be for medical use as well as industrial use, for example.

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

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

Example 1 A filter device having the structure shown in FIGS. 1 and 2 was manufactured. The filter member was manufactured by the manufacturing method described above. 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 degassing outlet: 4.3 mm Composition of porous material: Polyester screen mesh (pore diameter 32 μm) on both sides of polypropylene Sandwiched between nets (pore diameter 500 μm) Porous material thickness: 1.0 mm Bottom outer diameter of filtration member: 60 mm Top outer diameter of filtration member: 34 mm Bottom inner diameter of filtration member: 44 mm Top inner diameter of filtration member: 18 mm Height of filter member: 22 mm Number of pleats: 30 Filter effective area: 200 cm ² Filler composition: Polyurethane Filler bottom surface (cross pleats) Average tilt angle: 15 ° to horizontal Priming amount: 40 ml

(Comparative Example 1) A filtering apparatus similar to that of Example 1 was manufactured except that the structure of the filtering member was as follows.

Structure of Porous Material: Same as Example 1 Thickness of Porous Material: Same as Example 1 Bottom Outer Diameter of Filter Member: 47 mm Top Outer Diameter of Filter Member: 47 mm Bottom Inner Diameter of Filter Member: 31 mm Filtration Top inner diameter of member: 31 mm Height of filtering member: same as in Example 1 Number of pleats: same as in Example 1 Effective area of filtering member: same as in Example 1 Composition of filler: same as in Example 1 Lower surface of filler: Horizontal priming amount: 41 ml (substantially the same as in Example 1)

(Comparative Example 2) A filtering apparatus similar to that of Example 1 was manufactured except that the construction of the filtering member was as follows and the casing capacity was increased in accordance with the increase in size of the filtering member.

Structure of Porous Material: Same as Example 1 Thickness of Porous Material: Same as 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 filtering member: 42 mm Number of pleats: same as in Example 1 Effective area of filtering member: 400 cm ² (2.0 times that of Example 1) Composition of filler: same as in Example 1 Lower surface of the filler: horizontal Priming amount: 110 ml (2.75 times that of Example 1)

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

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

In the filtering apparatus of Example 1, a very small amount of bubbles adhered to the vicinity of the top of the filtering member, but they could be easily removed by applying a light vibration.

In each of the filtering devices of Comparative Examples 1 and 2, many air bubbles were observed near the top of the filtering member, particularly inside the ridges of the pleats (inside the filtering member).

From the above, it was confirmed that the filtering device of Example 1 was superior to the filtering devices of Comparative Examples 1 and 2 in the bubble removal property during priming.

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

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

[0068]

[Table 2]

As shown in Table 2, it was confirmed that in the filtration device of Example 1, the maximum diameter of the bubbles flowing out from the outflow port was small, and therefore the ability to remove bubbles was excellent.

On the other hand, the filter of Comparative Example 2 is slightly inferior to the filter of Example 1 in the bubble removing ability, but the priming amount is remarkably increased. Comparative Example 1
The filtration device of No. 1 has the same amount of priming as that of the filtration device of Example 1, but is inferior in the ability to remove bubbles.

[0071]

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

Further, when the filter member is constructed so that the outermost diameter thereof gradually increases from the top to the bottom, it is particularly advantageous for reducing the priming amount, and the flow condition in the first space is improved. Since this can be maintained, the ability to separate and remove air bubbles is further enhanced, and pressure loss can be reduced and hemolysis can be suppressed.

[Brief description of drawings]

FIG. 1 is a vertical cross-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 configuration diagram schematically showing an extracorporeal blood circulation circuit including the filtration device of the present invention.

[Explanation of symbols]

 1 Filtering Device 2 Housing 21 First Space 22 Second Space 23 Shaft 3 Bottom Body 4 Lid Body 51 Inlet 52 Outlet 53 Degassing Port 6 Filtering Member 7 Pleats 71 Mountain Inside 72 Valley 8 Filler 81 Lower Surface 82 Central part 83 Pleat crossing part 9 Filling material 10 Blood extracorporeal circulation circuit 11 Blood reservoir 12 Roller pump 13 Heat exchanger 14 Oxygenator 15, 16, 17, 18, 19 Tube 20 Patient

Claims (1)

[Claims] 1. A housing in which an inlet and an outlet for a liquid to be treated and a deaeration port are formed, a first space communicating with the inlet and a second space communicating with the outlet in the housing. A filtration device having a filtration member installed in the housing so as to be partitioned into a space, wherein the filtration member has a plurality of pleats of a porous material folded into a plurality of pleats arranged radially. Is formed into a tubular shape, and its top side opening is sealed with a filling material, and the surface of the filling material on the side of the second space has a central portion protruding toward the side of the second space. A filtration device characterized by being inclined so as to