JPH0576733A - Flat filter - Google Patents

Abstract

PURPOSE:To always, efficiently and sufficiently remove air accumulated in a filter chamber in a flat filter. CONSTITUTION:The space 12k in a filter chamber on the upstream side is preferably very thin, of about 200-300mum thickness. A housing 12a on the upstream side is made of material having spring ability so that it may bend outward by internal pressure generated in the space 12k while pushing out the air 13 from a vent hole 12f to deaerate it. When the upstream side housing 12a is expanded outward together with the internal pressure generated on the upstream side filter chamber space 12k, the peripheral part of an air reservoir 14 gets at the vent hole 12f formed on the upstream side housing 12a, causing the air 13 to be pushed out by the spring force of the upstream side housing 12a, permitting it to be suddenly discharged to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat type filter having a microfilter in a flat housing, which is often used in the fields of biology, chemistry and pharmacy for the purposes of aseptic filtration and sterilization filtration.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional flat type filter of this type. Reference numeral 2 denotes a housing containing the microfilter 1, which is composed of a flat plate-shaped upstream housing 2a and a container-type downstream housing 2b integrated with the upstream housing 2a. Each of the housings 2a, 2b has a pipe connecting portion 2c, 2d at the center thereof. The micro filter 1 is provided along the bottom of the downstream housing 2b. The sample liquid 5 is introduced from the pipe connecting portion 2c, reaches the filtration chamber 2e in the housing 2, passes through the micro filter 1, and is discharged from the pipe connecting portion 2d.

A vent hole 2f is formed at a predetermined position in the upstream housing 2a, and a vent film 2g is attached to the vent hole 2f. The vent hole 2f is for discharging the air contained in the sample solution 5.

By the way, this type of flat type filter is used in various directions, that is, in various postures. Conventionally, when air is contained in a sample solution, in many cases, depending on the posture, The air is not sufficiently discharged from the vent hole 2f, and a phenomenon called air lock occurs in which filtration stops at a part of the filter surface with which the air comes into contact, which causes a problem of reduction in filtration efficiency. This will be described in detail below.

FIG. 1 shows a filter having a pair of pipe connecting portions 2c and 2c.
d shows the state of being used along the horizontal direction. FIG. 1 (I) shows a state where the inside of the filtration chamber 2e is filled with the sample solution 5 and the sample solution is smoothly filtered. On the other hand, FIG. 1 (II) shows a state in which the air contained in the sample solution 5 becomes bubbles 3 and rises to the upper part of the filtration chamber 2e to form an air reservoir 4 therein. That is, in general, the air contained in the sample liquid 5 is difficult to pass through the microfilter 1, so that such an air pool 4 is generated. In this way, when the air pocket 4 is generated, naturally,
The upper part of the microfilter 1, that is, the part in contact with the air reservoir 4 does not participate in the filtration (partial airlock). That is, the efficiency of filtration is reduced. Then, as shown in FIG. 1 (III), the air is released to the outside through the vent hole 2f only when the liquid pool 4 grows and reaches the site of the vent hole 2f. .. However, the air in the air reservoir 4 formed above the vent hole 2f of the filtration chamber 2e does not have a place to escape, so that the upper portion of the microfilter 1 is not always involved in the filtration and the filtration effective area is very small. Will be filtered by.

In contrast to the above-mentioned use example, the pipe connection portion 2c on the supply side is now on the lower side, while the pipe connection portion on the discharge side is 2d.
When this filter is used in a position in which the upper side of the filter chamber is set to the upper side, when air is collected on the entire upper surface of the filtration chamber 2e, a complete film-like air layer is formed there, and the sample solution cannot be further sent. In some cases, a so-called complete airlock may occur.

[0007]

SUMMARY OF THE INVENTION Therefore, the technical problem to be solved by the present invention is, in a flat type filter having a built-in micro filter, to constantly and efficiently remove the air in the air pool grown in the filtration chamber. It is to be configured so that it can be evacuated to the outside.

[0008]

In order to solve the above technical problems, the present invention provides a flat type filter having the following structure.

That is, in this filter, a micro filter is provided in the filter chamber of the housing, and a vent hole with a vent film is formed at a predetermined position of the upstream housing 12a upstream of the micro filter. The upstream filter chamber space formed by the microfilter and the inner surface of the upstream housing 12a is formed in a flat shape. Further, the upstream filtration chamber space has a dimension configuration that is sufficiently thin so that the sample liquid is filled with the interfacial tension in a film shape. Further, the upstream housing has a spring property in which, when air is trapped in the upstream filtration chamber space, it flexes outward due to its internal pressure and pushes the air out of the vent hole so as to be degassed.

In the above structure, the housing preferably has a flat disk shape, the upstream housing has a liquid supply passage in the center thereof, and the downstream housing constituting the downstream side of the housing 12 also has It is preferable to have a drainage passage in the center.

There may be one or a plurality of vent holes, and it is preferable to form them in a portion near the liquid supply passage.

The thickness of the upstream filtration chamber space is generally preferably 1000 μm or less, preferably 100 μm to 500 μm, and more preferably 200 μm to 300 μm.

In the above structure, if air now flows into the filtration chamber together with the sample liquid, the internal pressure naturally rises because the sample liquid is continuously sent, and the internal pressure causes The upstream housing having a spring property flexes outward, that is, expands, the thickness of the upstream filtration space increases, and a guide space for diffusing air into the surroundings is formed.

When the air reservoir reaches the vent hole in this manner, the spring force of the upstream housing rapidly releases the air through the vent hole, and the air is efficiently degassed.

Thus, according to the present invention, the intended technical problem can be sufficiently solved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS.

FIG. 2 shows the entire flat disc type filter according to the present embodiment, and FIG. 3 shows an enlarged state of its essential parts.
As shown in FIGS. 2 and 3, this filter has a housing 12 including an upstream housing 12a and a downstream housing 12b. These housings 12
Each of a and 12b has a substantially disc shape. The pipe connecting portions 12c and 12d are joined to the central portions of the housings 12a and 12b. A liquid supply passage 12i for supplying the sample liquid and a drainage passage 12j for discharging the filtered sample liquid are formed in the pipe connecting portions 12c, 12d, respectively.

A flat filtration chamber 12e is formed inside the housing 12. Then, the microfilter 10 is stretched in the filtration chamber 12e.

A vent hole 12f is formed in the upstream housing 12a in the vicinity of the periphery of the pipe connecting portion 12c. A vent film 12g is formed inside the vent hole 12f.

The upstream filtration chamber space 1 formed by the microfilter 10 and the inner surface of the upstream housing 12a.
The 2k is formed in a flat shape and has a sufficiently thin size configuration so that the sample liquid 15 can be filled with the interfacial tension thereof, in other words, as if a single liquid film is formed.

By the way, at least the upstream housing 1
2a is made of a material having a spring property, which bends outward due to the internal pressure of the air trapped in the upstream filtration chamber space 12k while pushing out the air 13 from the vent hole 12f to degas it. .. That is, plastic is preferable as the material, for example, polycarbonate,
Polypropylene is the best choice. Downstream housing 12
The b may also be made of the same material as the upstream housing 12a.

Known microfilters are used as the microfilter 10, and hydrophilic membranes and hydrophilized membranes in general can be used. For example, cellulose-based filters and polysulfone-based filters can be used.

A well-known vent film 12g is used,
All hydrophobic membranes can be used. That is, this vent membrane is made of a material that does not allow the sample liquid 15 to pass through and quickly escapes only air, and is preferably one having high water repellency and a large air permeation flow rate. As the material, tetrafluoroethylene or polypropylene is suitable.

As shown in detail in FIG. 3, the inner surface of each of the upstream housing 12a and the downstream housing 12b is provided so that the sample solution 15 filled in the filtration chamber 12e can be spread over the entire filtration chamber. A large number of concentric and radial grooves 12h are formed.

As shown in FIG. 4, the upstream filtration chamber space 12
The preferable thickness dimension t of k differs depending on the properties of the sample liquid in order for the sample liquid to form one liquid film due to its interfacial tension, but as described above, it must be 1000 μm or less, Desirably 100 μm to 500 μm
And the optimum range is 200 μm to 300 μm.

FIG. 5 illustrates the usage state of the flat disc type filter having the above structure.

FIG. 5 (I) shows a state in which the sample solution 15 is normally filtered from the upstream side to the downstream side by the micro filter 12 and discharged to the downstream side. On the other hand, FIG.
I) shows a state in which the air 13 contained in the sample liquid 15 enters the filtration chamber 12e. FIG. 5 (III) shows a state in which the air 13 is pushed to the inside of the filtration chamber 12e.
As shown in the figure, since the upstream filtration chamber space 12k is formed very thin, the sample liquids 15 filled therein are strongly bonded to each other by interfacial tension to form one liquid film. Therefore, the air 13 does not easily disperse around it. However, the internal pressure of the upstream filtration chamber space 12k rises due to the liquid pressure of the continuously sent sample liquid, and as shown in (III) by the internal pressure, the upstream housing 12a has a section V It bends outward in the shape of a letter. By doing so, the air 13 can move in the circumferential direction inside the upstream filtration chamber space 12k, and when the peripheral portion of the air reservoir 14 reaches the vent hole 12f, the upstream housing 12 that has expanded has expanded.
Air 1 pushed by the spring force of a, that is, the restoring force
3 is rapidly discharged to the outside, and the initial state of FIG.
After returning, the accumulated air 13 is completely discharged to the outside.

As described above, according to the above-described embodiment, the air lock, which has been a serious problem in the past, that is, the problem such as a sharp decrease in filtration efficiency, has a simple structure, and it can be used in the direction of use of the filter. Regardless, it can be resolved almost completely.

[Brief description of drawings]

1 (I), (II), and (III) are cross-sectional views of essential parts showing the action of a conventional flat disc filter.

FIG. 2 is a partial cross-sectional overall view of a flat disc filter according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part of FIG.

FIG. 4 is an enlarged sectional view of a main part of FIG.

5 (I), (II), and (III) are cross-sectional views of essential parts showing a usage state of the flat disc type filter of FIGS.

[Explanation of symbols]

10 Micro filter 12 Housing 12a Upstream housing 12b Downstream housing 12c, 12d Pipe connection part 12e Filtration chamber 12f Vent hole 12g Vent membrane 12h Guide groove 12i Liquid supply passageway 12j Drainage passageway 12k Upstream filtration chamber space 13 Air 14 Air pool 15 Sample solution

Claims (5)

[Claims] 1. A microfilter (10) is provided in a filtration chamber (12e) of a housing (12),
The upstream side housing (12
A flat filter having a vent hole (12f) with a vent membrane (12g) formed at a predetermined position of (a), comprising a micro filter (10) and an upstream housing (12a).
The upstream-side filtration chamber space (12k) formed by the inner surface of and is formed in a flat shape, and has a dimension configuration that is sufficiently thin so that the sample solution (15) is filled with the interfacial tension in a film shape. The upstream housing (12a) bends outward due to the internal pressure of the air trap (14) generated in the upstream filtration chamber space (12k) while removing the air (13) from the vent hole (12f). A flat type filter characterized by having a spring property that pushes out as much as possible. 2. The housing (12) has a flat disk shape, and the upstream housing (12a) has a liquid supply passage (12i) in the center thereof, and is a downstream forming a downstream side of the housing (12). The flat type filter according to claim 1, wherein the side housing (12b) also has a drainage passage (12j) in the center thereof. 3. The flat type filter according to claim 1, wherein a thickness dimension of the upstream side filtration chamber space (12k) is 1000 μm or less. 4. The flat type filter according to claim 1, wherein a thickness dimension of the upstream side filtration chamber space (12k) is 100 μm to 500 μm. 5. The flat type filter according to claim 1, wherein a thickness dimension of the upstream side filtration chamber space (12k) is 200 μm to 300 μm.