JPS625003B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an improvement in a filtration device of the form commonly used in chemical or other laboratories for the filtration of liquids, such as for qualitative or quantitative analysis of solids filtered from liquids. The present invention relates to a filtration device whose filter can be easily removed when carrying out gravimetric analysis in which it is desired to identify a person's identity.

BACKGROUND ART U.S. Patent no.
No. 3831759 discloses a liquid filtration device that includes a storage member that receives a liquid to be filtered and an outlet member that discharges the filtered liquid, and a disc-type filter is disposed between the two members. one member is provided with an annular magnet and the other member is provided with a ring of annular magnet or other ferromagnetic material, and the disc-shaped filter is The two members are tightly clamped by magnetic attraction. The filtration device of the above patent is commonly used and allows for rapid assembly and disassembly, which is particularly desirable for the insertion and removal of disc-shaped filters, as well as the storage and outlet members of disc-shaped filters during filtration. It has been somewhat successful and effective in that a good seal can be obtained between the two. However, it has been a problem that magnetic and ferromagnetic materials suffer from performance degradation. Such performance deterioration is caused by corrosion due to contact with acidic or other corrosive liquids, or by cracking or cracking when ceramic magnets are used. In particular, regarding the latter point, ceramic magnets such as alkali metal or alkaline earth metal ferrites are lightweight, relatively low cost, and have strong magnetic force, but they do not break or crack. The disadvantage is that it is easy to

The present invention relates to an improvement over the device covered by the above-mentioned patent, and relates to an improvement in a filtration device that utilizes ceramic magnets to obtain all the advantages of ceramic magnets and is constructed to eliminate the disadvantages mentioned above.

BRIEF DESCRIPTION OF THE INVENTION In the filtration apparatus of the present invention, the reservoir member and the outlet member are made of organic plastics, and have a relatively large magnetic attraction force required to tightly and tightly crack the disc-shaped filter. Each of the above-mentioned members is provided with an annular ceramic magnet in order to provide it at low cost and without excessive weight, and the annular ceramic magnet of the above-mentioned storage member is provided in the organic plastic of this storage member. The ceramic magnet of the outlet member is completely enclosed within a closed annular cavity, the annular magnet being smaller in size than the annular cavity, and the ceramic magnet of the outlet member is completely enclosed within the annular cavity of the organic plastic of the outlet member. The annular magnet is also smaller in size than the annular cavity it is surrounded by. Therefore, the above-mentioned ceramic magnets are well protected against contact with corrosive liquids and, more importantly, are susceptible to cracking or cracking due to impact, since they are completely surrounded by the organic plastic. Organic plastics absorb considerable shock and shock caused by the use of filtration equipment and harsh use. Furthermore, since each magnet is smaller than the cavity it surrounds, organic plastics can be heated, especially when the filtration device is heated, e.g. in an autoclave, as is often required when the filtration device is used in medical laboratories. /or the ceramic has enough room to expand without stress.

These and other features and advantages of the invention will become apparent from the detailed description below.

BEST MODE FOR CARRYING OUT THE INVENTION Now, referring to the accompanying drawings, the filtration device of the present invention includes a storage member 2, an outlet member 4, a support net 5, and a disc-shaped filter 6. This disc-shaped filter is placed and clamped between the reservoir member and the outlet member when they are assembled.

The reservoir member comprises a mold of an organic plastic or solid organic polymer material, preferably transparent or at least translucent, and sufficiently heat resistant to permit heat sterilization, typically comprising: Preferably, it is a polysulfone or polycarbonate-based thermoplastic resin. The reservoir member is open at its upper end for receiving the liquid to be filtered, and the base of the reservoir member is provided with an opening 8 in its center, around which opening there is a flat annular surface facing downwards. 10, and this annular surface 10 receives the peripheral portion of the disc-shaped filter 6 when the disc-shaped filter is sandwiched between the outlet member and the storage member and both members are assembled. The base of the reservoir member is shaped to provide an annular groove between downwardly extending cylindrical flanges 14 and 16, with the downwardly facing annular surface 10 intersecting the downwardly extending cylindrical flange 1.
It lies within a cylindrical recess 18 defined by 4. An annular ceramic ferrite magnet 20 is placed within the groove and a flat annular body 22 preferably formed of the same organic plastic as the mold described above.
is sealed within the groove by. The inner and outer edges of the annulus 22 are joined to the flanges 14 and 1 so that the annulus of organic plastic becomes an integral part of the reservoir member.
6 are each hermetically joined, for example by heat bonding, to the lower ends of the annular ceramic magnets 6 to create a closed annular cavity 12 which completely surrounds the annular ceramic magnet. This seals the magnet within the organic plastic of the reservoir member.

Further, in accordance with the present invention, as best shown in FIG.
The size is smaller than 2. That is, the inner diameter of the magnet is larger than the diameter of the cylindrical inner wall of cavity 12, the outer diameter of the magnet is smaller than the diameter of the cylindrical outer wall of cavity 12, and the height or thickness of the magnet is smaller than the height of cavity 12.
There is therefore space between the magnet and each cylindrical side of the cavity, and when the device is assembled and placed in the normal orientation shown, there is also space between the top surface of the magnet and the top surface of the cavity. There is. This relatively small size of the magnet relative to the size of the cavity and the spacing between them is particularly useful when filtration devices are used in medical laboratories, as is often required, e.g. This is important in that it allows room for the ceramic magnet and organic plastic material to expand when the filtration device is heated in the autoclave. The heat of the organic plastic and ceramic magnets can be minimized when selecting the organic plastic and magneto-ceramic materials used by loosening the fit between the magnet and the cavity to allow room for relative expansion of the magnet and organic plastic. There is no need to consider the difference in expansion. In the particular embodiment shown herein, the organic plastic used as the reservoir member and the outlet member has a higher coefficient of thermal expansion than the ceramic ferrite magnet, but the aforementioned feature of being able to expand without creating stress does not It will not cause any inconvenience.

In fact, in the example shown here, at normal room temperature, the average diameter of the magnet is about 6.5 cm (about 2.6 inches) and its height is about 6.3 mm (about 0.25 inch); The cavity between each side of the magnet and the adjacent side wall of the cavity is approximately 0.63 mm (approx.
0.025 inch) and a similar spacing between the axial end face of the magnet and the axially adjacent end face of the cavity. Of course, the exact spacing required will depend on the size of the device being formed and thus the size of the magnets used.
Depending on the extent of the difference in thermal expansion coefficients between the ceramic and organic plastic materials of the magnets used, in any case the magnets and the cavity will It is best to have a spacing slightly larger than theoretically required, as a slight spacing between the two will not introduce any defects.

The outlet member 4 preferably consists of an organic plastic molding having the same properties as the reservoir member;
It has a head 30 and a tube 32 extending downwardly from the head to discharge the filtered liquid.
The head has an aperture 34 of approximately the same diameter as the reservoir member aperture 8 and opens into an outwardly flared upper portion 36 of the tube 32. The support screen 5 is placed in the opening 34 and rests on a ledge defined by the circumference of the upper end of the flared tube section 36. The support net that supports the central portion of the disc-shaped filter 6 has a grid-like central portion that forms the holes necessary for passing the flow of the filtered liquid, and an inner peripheral portion. The screen can be made of the same or similar organic plastic as the outlet member. Preferably, the support screen is a separate part that can be removed from the outlet member to facilitate cleaning after the filtration operation.

Surrounding the opening 34 is an upwardly facing flat annular surface 38 which rests on a cylindrical projection 40 of substantially the same diameter as the cylindrical recess 18 of the reservoir member. Therefore, when the outlet member to which the supporting net is attached is assembled into the reservoir member by enclosing the disc-shaped filter 6, the peripheral portion of the disc-shaped filter is aligned with the annular surface 36 facing upward of the outlet member. and a downwardly facing annular surface 10 of the reservoir member and supported thereto.

There is an upwardly directed annular groove around the head of the outlet member, the sides of which are surrounded by cylindrical walls 44 and 46.
The groove receives an annular ceramic ferrite magnet 48. A thin flat ring 50, preferably made of the same organic plastic that formed the mold of the outlet member, is fitted tightly against the top surface of the cylindrical walls 44 and 46 so that it becomes an integral part of the outlet member. A closed annular cavity 42 is formed which completely surrounds the annular ceramic magnet 48. The magnet 48 is thus sealed within the organic plastic of the outlet member.

Also, as best shown in FIG.
8 is smaller in size than the cavity 42 in which it is enclosed, and the foregoing description of this feature (other than the reference numeral) with respect to the magnet 20 and cavity 12 is in relation to the magnet 48 and cavity 42 of the outlet member. The same features also apply. When assembling the filtration device, the second
As shown in FIG. 5 and FIG.
is pulled upward against the top plate of the However,
When the outlet member is removed from the reservoir member,
As shown in FIG. 3, it will be seen that the magnet 48 falls against the underside of the cavity 42, creating a space between the magnet and the top plate of the cavity.

The loose fit between each magnet and its cavity allows the magnets to move in all lateral and axial directions when the filtration device is not assembled, but when the filtration device is assembled. The magnetic attraction between both magnets holds the magnets in a fixed position within the cavity. Although it is not a problem if the magnet rattles when the filtration device is not assembled, if it is desired to eliminate such rattling, a compressible resilient foam material or a similar material may be used. An annulus of similar material may be placed between the top surface of the magnet and the top surface of the cavity for the reservoir member and between the bottom surface of the magnet and the bottom surface of the cavity for the outlet member. Alternatively or additionally, such foam material can be placed between one or both sides of the magnet and one or both walls of the cavity.
However, this is costly, and also requires the use of foam or similar materials that are sufficiently heat resistant to withstand the heat of the autoclave, and the filtration equipment is heated and the foam or similar materials are heated. It is necessary to size the cavity to receive this material when placed in a compressed state.

Outlet member magnets 48 are of substantially the same diameter as reservoir member magnets 20, and these magnets are similar to magnets 48 when the reservoir and outlet members are assembled.
The upper surface and the lower surface of the magnet 20 are arranged adjacent to each other and facing each other. Each magnet is permanently magnetized such that one axial end thereof is of one polarity and the other axial end thereof is of the other polarity, and these magnets are such that the top surface of magnet 48 is the bottom surface of magnet 20. and are arranged so that they have opposite polarities. (In Figure 2, this state is shown by making the upper surface of the magnet 48 the north pole and the lower surface of the magnet 20 the south pole, but it is understood that the opposite polarity may be used. ) Therefore, when the storage member and the outlet member are assembled with the disc type filter sandwiched between them as shown in FIG.
The magnetic attraction between adjacent surfaces of the magnets hermetically clamps the circumference of the disc-shaped filter between the annular surfaces 10 and 38 of each of the reservoir and outlet members.

In the preferred embodiment shown, the upwardly facing annular surface 38 is provided with an annular surface 38 to allow for easy and reliable centering of the disc-shaped filter relative to this surface 38.
It is bounded by an upwardly extending thin flange 52, and the upwardly facing annular surface 10 of the reservoir member is bounded by a thin, upwardly extending flange 52.
It is bounded by a downwardly directed annular groove 54 which receives the two.

The dimensions of the cylindrical flanges 14 and 16 and walls 44 and 46 and the thickness of the organoplastic flat annulus 22 and 50 are such that the reservoir and outlet members are assembled as shown in FIGS. When the magnet is closed, a thin gap 56 is created between the opposing organic plastic surfaces covering the magnet, and the magnetic attraction between the magnets causes the desired periphery of the disk-shaped filter between the annular surfaces 10 and 38 to be formed. Preferably, the size and thickness are such as to ensure that a clamping action of . Assuming that the organic plastic mold and magnet are manufactured to dimensions within generally accepted manufacturing tolerances, to ensure that opposing organic plastic surfaces do not touch each other when the parts are assembled, Nominal 0.5mm
(0.020 inch) gap 56 is generally sufficient. Since the magnetic attraction between the magnets is a function of the distance between opposing surfaces of opposite polarity, each organoplastic ring 50 is no more than 2 mm (0.080 inch) thick. In the example shown here, ring body 2
The thickness of ring 50 is 1 mm (0.040 inch) and similarly the thickness of ring 50 is 1 mm. The thickness of the organoplastic ring between the opposing faces of both magnets slightly reduces the magnetic attraction for a given magnet size, but this adds only a small amount of cost, but can be achieved by using a slightly larger magnet. Can be easily compensated. However, in this case, the condition that each of these slightly larger magnets is loosely placed within its cavity must be taken into account, as mentioned above.

In the embodiment shown, each annulus cavity 12 and 42 has a flat annulus 22 and a groove formed in a plastic mold and a flat annulus 22 and 42 that are thermally bonded and sealed to the plastic mold to form a cavity lid. 50, respectively. In a variant that helps to simplify manufacturing, the ceramic magnet can be enclosed and sealed within a hollow, thin-walled, closed organic plastic ring (the internal dimensions of the plastic ring are such that the magnet and the This assembly of the annular magnet within the hollow organoplastic closed ring is then sized to provide the desired spacing between the enclosed cavity and the enclosing cavity. The outlet member or reservoir member is joined by fitting into an annular groove at the open end of the plastic mold. As yet another variant,
The annular surface 10 of the reservoir member can be narrow in width, i.e. the dimension between its inner and outer diameters can be reduced, or it can have a downwardly protruding shape on a radial line, i.e. an edge-like shape (in cross section). You can also
This makes it possible to reduce the contact area between the annular surface 10 and the disc-shaped filter and increase the sealing force per unit contact area under the magnetic attraction force of the magnet during assembly of the device. Although specific embodiments of the invention have been described above, it will be understood that various changes and modifications may be made within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing a preferred embodiment of the filtration device of the present invention, and FIG. 2 is an enlarged partial cross-sectional side view showing the filtration device shown in FIG. FIG. 3 is a partially cutaway side view showing a part of the outlet member of the filtration device shown in FIGS. 1 and 2, and FIG. 4 is a side view of the filtration device shown in FIGS. 1 and 2. FIG. 5 is a partial cross-sectional side view showing a portion of the reservoir member broken away, and FIG. 5 is a view similar to FIG. 2... Storage member, 4... Outlet member, 3... Supporting net, 6... Disc type filter, 8... Opening,
10... Flat annular surface, 14, 16... Cylindrical flange, 20... Magnet, 22... Flat ring body, 3
0... Head, 32... Tube, 34... Opening, 38...
...Flat annular surface, 40...Cylindrical projection, 44,4
6... Cylindrical wall, 48... Magnet, 50... Flat ring, 52... Flange, 54... Groove, 56...
...Gap.

Claims (1)

[Claims] 1. An organic plastic reservoir member for receiving the liquid to be filtered, the base of the reservoir member having an opening extending therethrough, and a downwardly facing annular surface surrounding the opening. The annular surface receives the circumferential portion of the disc-shaped filter; and further includes an organic plastic outlet member for discharging the head and the filtered liquid. a tube depending from the head; the head has an opening communicating with the tube; the opening is surrounded by an annular surface facing upward; the annular surface is connected to the disk; the base of the reservoir member has an annular ceramic permanent magnet completely enclosed within the closed annular cavity of the organic plastic of the reservoir member; and a wall of the cavity, the head of the outlet member being within the closed annular cavity of the organic plastic of the outlet member. a completely surrounded annular ceramic permanent magnet, the annular magnet being smaller than the annular cavity in which it is surrounded, such that there is a spacing between the annular magnet and the wall of the cavity in which it is surrounded; when the outflow port member and the storage member are assembled with a disk-shaped filter sandwiched between them, the annular magnet of the outflow port member is disposed adjacent to the annular magnet of the storage member; . A liquid filtration device, wherein a peripheral portion of the disc-shaped filter is tightly clamped between the annular surfaces by magnetic attraction between the annular magnets. 2. One of the annular surfaces is within a cylindrical recess provided on one of the members, and the other of the annular surfaces is on a cylindrical protrusion provided on the other of the members, and the other of the annular surfaces is in contact with the outlet member. When these members are assembled by narrowing the disc-type filter between them and the storage member, it is removably telescopically fitted into the above-mentioned recess, and as a result, the above-mentioned circular 2. The filtration device according to claim 1, wherein the peripheral portion of the plate filter is tightly clamped between the annular surfaces. 3. The ceramic magnet of each said member is received within an annular groove of said member and capped by an organoplastic ring, which ring is glued to the wall of said groove so as to be an integral part of said member. 2. A filtration device according to claim 1, wherein said member is configured to form a closed annular cavity. 4. The arrangement of the magnets and the thickness of the organic plastic rings are such that a gap is formed between the organic plastic rings when the storage member and the outlet member are assembled to narrow the disc-shaped filter. The filtration device according to claim 3, which has the following properties: 5 The thickness of the ring of the above organic plastic is 2 mm.
(0.080 inches) or less. 6 Each of said magnets is magnetized such that one axial end thereof has one polarity and the other axial end thereof has an opposite polarity, and said magnets are magnetized in such a way that when said members are assembled, said magnets The filtration device according to claim 1, wherein the axial ends of the magnets are arranged so as to have opposite polarities. 7. The filtration device according to claim 1, wherein the opening in the head of the outlet member has a net for supporting the filter.