JPH0317938Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention allows a liquid sample, such as a plasma sample, to pass through a microporous filtration membrane (so-called ultrafiltration membrane) to separate proteins and produce protein-free plasma. This relates to a liquid filter used for obtaining liquids.

[Conventional technology]

In this type of liquid filter, the pore size of the filtration membrane is extremely small, and the liquid cannot be filtered under atmospheric pressure. Therefore, three main methods have been adopted in the past. The first is to integrally form an upper housing with an open top surface and a lower housing having a drain pipe through an ultrafiltration membrane, and provide a Lua taper in the drain pipe inner hole of the lower housing. A syringe tip nozzle is inserted into the syringe, and by suctioning the syringe, a negative pressure is created in the space below the ultrafiltration membrane, and the liquid sample injected into the upper housing is filtered by the suction force; The second is one that applies a centrifugal separation method, and the third is an upper casing that has a liquid injection pipe equipped with a check valve, as described in Japanese Utility Model Application Publication No. 1983-6712, which was filed by the applicant earlier. and a lower housing having a drainage pipe are integrally formed via an ultrafiltration membrane, a Luer taper is provided in the inner hole of the liquid injection pipe of the upper housing, and the tip nozzle of the syringe is inserted into this. There are three types in which a liquid sample is injected with air using a syringe to create a positive pressure in the space above the ultrafiltration membrane, and the liquid sample is filtered by that pressure.

Although there is no particular difference in the filtration effect between these methods, in the first case, the plunger of the syringe must be held in a suction state during filtration, and a special jig is required for this purpose. Summer,
Once the sample passes through the filtration membrane, it is collected in a syringe, and it is necessary to transfer the collected sample to a test tube, etc., which not only requires extra man-hours, but also wastes the sample that adheres to the syringe. There was a problem. In addition, in the second case, since it is necessary to install a centrifuge, there is a problem that it is not possible to easily filter the product, and it takes time and effort.

On the other hand, in the third case, the liquid sample and positive pressure air injected into the upper housing are retained within the upper housing by the action of the check valve, so the positive pressure remains even after the syringe is removed. It has the advantage that it can be maintained, there is no need to use special jigs, and the filtered liquid can be directly collected into test tubes etc. for sample testing.

However, in the case of liquid filters that adopt the third method above, the upper and lower casings are integrally formed by ultrasonic welding through an ultrafiltration membrane. Vibrations caused by sound waves may tear the supporting part of the membrane, and the pore size of the membrane may be distorted due to the welding temperature (the pore size becomes larger,
There was a risk of protein leakage, and it was necessary to replace all the filters and syringes every time one sample was filtered, resulting in high costs.

[Purpose of invention]

This idea is intended to solve the above problems all at once, and it is sufficient to simply lock (join) the liquid injection pipe with a check valve and the cylindrical casing without using any welding means such as ultrasonic waves. In addition, complete airtightness of the joint can be maintained, and depending on the sample filling method, only the sample storage housing needs to be replaced for each sample to be filtered, and the injection tube and syringe can be used repeatedly, making it economical and advantageous. The purpose is to provide liquid filters.

[Structure of the idea]

This device has an inner circumferential wall of a cap body through which a tube with a check valve is provided in the center of the top surface, an opening on the top surface that can fit into the lower part of the tube, and a drain pipe on the bottom surface. A means for easily engaging and disengaging from the outer periphery of the opening of a sample accommodating cylindrical body having A cylindrical member that can be interposed between the annular shelf and the annular step provided on the inner surface of the top wall of the cap body or the outer circumferential wall of the tube body facing it is provided, and tightening when connecting the cap body to the sample storage cylinder is provided. The structure is such that the connecting portion can be airtight and the peripheral edge of the plate-like filtration membrane can be reliably pressed against the annular shelf by force.

〔Example〕

Next, this invention will be explained based on an embodiment shown in the accompanying drawings.

Reference numeral 1 denotes a cap body made of a transparent material (for example, plastic or glass), and the cap body 1 is provided with finger-holding protrusions 2 on the outer circumferential wall and spiral protrusions 3 on the inner circumferential wall.

Reference numeral 4 denotes a tube provided in a penetrating manner in the center of the top surface of the cap body 1, and an inner hole in the upper part 4a of the tube 4 is provided with a syringe 5.
It has a luer tapered shape so that the tip nozzle 5a can be fitted therein.

Reference numeral 6 designates a check valve, and the check valve 6 is shown in FIG. 1 by attaching a tubular rubber member 6a in the shape of a cylinder with a bottom to an annular protrusion 7 provided in the middle part of the tube body 4, and one part of the rubber member 6a. A slit 6b is provided on the side surface, and FIG. 3 shows a slit 6b' provided at the tip of a papillary rubber material 6a' in the annular protrusion 7, but other structures may also be used. The material may be employed in the same location as above or in a different location.

Reference numeral 8 denotes a sample accommodating cylinder having an opening 8a on the top surface that can fit into the outer periphery of the lower part 4b of the tube body 4, and a drain pipe 9 on the bottom surface. It is molded from a material (which may be a different material). The inner bottom surface of the sample storage cylinder 8 is shaped like a mortar, so that liquid can be collected in a drain pipe 9. A projecting piece 10 is provided on the outer periphery of the opening of the sample storage cylinder 8, which can be coupled to the spiral projecting strip 3 provided on the inner circumferential wall of the cap body 1.

Reference numeral 11 denotes a plate-shaped filtration membrane (so-called ultrafiltration membrane) having a large number of fine pores, and the periphery of the plate-shaped filtration membrane 11 is placed on an annular shelf 12 provided around the inner bottom surface of the sample storage cylinder 8. It is starting to be placed. The central portion of the plate-shaped filtration membrane 11 is supported by a large number of ribs 13 provided on the mortar-shaped inner bottom surface of the sample storage cylinder 8 in a manner that does not impede the flow of the filtrate.

Reference numeral 14 denotes a cylindrical member interposed between the annular shelf portion 12 and an annular step portion 15 provided on the lower outer circumferential wall of the tubular body 4 of the cap body 1 so as to oppose this. It is desirable to use a material that itself has elasticity.

Reference numeral 16 denotes an O-ring fitted into the annular stepped portion 15 to maintain airtightness with the upper end edge of the cylindrical member 14. Note that the upper end edge of the cylindrical member 14
It goes without saying that it may be applied to the inner surface of the top wall of the cap body 1 instead of being applied to the surface.

When connecting the cap 1 and the sample storage cylinder 8, first insert the plate-shaped filtration membrane 11 through the opening of the sample storage cylinder 8 along its inner diameter, and then attach the peripheral edge to the annular shelf 12. Let it be placed. Next, cylindrical member 1
4 is inserted as shown in the second figure, and its lower edge is pressed against the peripheral edge of the plate-shaped filtration membrane 11. Thereafter, the lower part 4b of the tubular body 4 of the cap body 1 is inserted into the opening of the sample housing cylinder 8, and the spiral protrusion 3 provided on the inner peripheral wall of the cap body 1 is inserted into the protruding piece 10 of the sample housing cylinder 8. When engaged with and rotated in the screwing direction, the spiral protrusion 3 and the protrusion piece 10 are easily locked (coupled). As a result, the upper edge of the cylindrical member 14 comes into contact with the O-ring of the annular step portion 15, and the plate-shaped filtration membrane 11 is pressed onto the annular shelf portion 12.

Next, a case will be described in which the filter of the above embodiment is used to ultrafiltrate a liquid sample, such as a plasma sample.

First, the sample storage cylinder 8 from which the cap body 1 has been removed
After injecting an appropriate amount of plasma sample into the cap using a dispensing pipette (not shown), the cap 1 is connected as described above.

Next, after pulling the plunger of the syringe 5 in the air to take in a certain amount of air into the syringe barrel, the tip nozzle 5a of the syringe 5 is tightly coupled to the inner hole at the outer end of the tube body 4 of the cap body 1. When the plunger is pushed in, the air inside the syringe 5 will flow into the cap body 1.
In addition to the internal air, the air is injected into the space created by the cylindrical member 14 and the plate-shaped filtration membrane 11 (hereinafter simply referred to as internal space). Moreover, the air once injected does not flow backward due to the action of the check valve 6 provided in the tube, and is completely captured, so that the inside of the sample storage cylinder 8 becomes a positive pressure. Therefore, the sample is pressed by the pressure in the internal space, passes through the plate-shaped filtration membrane 11 which is an ultrafiltration membrane over time (within approximately 30 to 60 minutes), oozes into the lower space, and is discharged. The liquid is received from the liquid pipe 9 into a certain container (not shown) and subjected to a certain test. In this case, cap body 1
The sample storage cylinder 8 has a spiral protrusion 3 and a protrusion piece 10.
They are firmly connected by the engaging and disengaging means, and the connected portion is kept completely airtight by the cylindrical member 14, and the degree of compression of the plate-shaped filtration membrane 11 is also high, so that the air in the internal space is It functions effectively as a force to press the sample. Note that as the sample is filtered, the air pressure in the upper space decreases for a while, but in such a case, by reinjecting air with the syringe 4, it is possible to easily restore the internal space to a positive pressure state again. It becomes possible.

[Effect of idea]

As described above, the liquid filter according to this invention has an inner circumferential wall of the cap body through which a tube body with a check valve is provided in the center of the top surface, and an opening that can fit into the lower part of the tube body on the top surface. and a means for easily engaging and disengaging from the outer periphery of the opening of a sample accommodating cylinder having a drain pipe on the bottom surface, and placing the peripheral edge of the plate-shaped filtration membrane around the inner bottom surface of the sample accommodating cylinder. The present invention is characterized in that it is provided with an annular shelf, and a cylindrical member that can be interposed between the annular shelf and an annular step provided on the inner surface of the top wall of the cap body or the outer circumferential wall of the tube body facing the annular shelf. Therefore, it has a higher degree of perfection than the conventional method in which the upper and lower casings are manufactured by welding means using ultrasonic waves, etc., and can perform quick and reliable liquid filtration. This has an excellent effect.

[Brief explanation of the drawing]

The figures show one embodiment of this invention; Fig. 1 is a cross-sectional view when a sample is press-fitted; Fig. 2 is an exploded perspective view of the cap body and sample-accommodating cylinder; and Fig. 3 shows another example of the check valve. FIG. DESCRIPTION OF SYMBOLS 1... Cap body, 3... Spiral protrusion, 4... Tube body, 6... Check valve, 8... Sample storage cylinder, 9...
Drain pipe, 10...Protruding piece on the outer periphery of the opening, 11...
plate-shaped filtration membrane, 12... annular shelf, 13... rib,
14... Cylindrical member, 15... Annular stepped portion, 16... O
ring.

Claims (1)

[Scope of utility model registration request] A sample storage device having an inner circumferential wall of a cap body having a tube with a check valve extending through the center of the top surface, an opening on the top surface that can fit into the lower part of the tube, and a drain tube on the bottom surface. Providing a means for easily engaging and disengaging from the outer periphery of the opening of the cylinder, and providing an annular shelf around the inner bottom surface of the sample storage cylinder on which the periphery of the plate-shaped filtration membrane can be placed;
A liquid filter characterized in that a cylindrical member is provided that can be interposed between the annular shelf and an annular step provided on the inner surface of the top wall of the cap body or the outer circumferential wall of the tube body facing the annular shelf.