Filter holder and filter holding method

Abstract

To provide a filter holder suitable for preventing wrinkles from being formed on a filter when fixed or dried and preventing excessive force from applying to the filter during a drying process.SOLUTION: A filter holder includes a base plate 10, a cover 20 for covering a central part 12 of the base plate, and a magnetic member for fixing both by magnetic force. The central part of the base plate 10 is thinner than both ends 14A and 14B and flat, and there are steps formed at the boundary therebetween. The central part 12 has a base plate opening 18. The cover 20 overlaps the central part 12 of the base plate 10 and has a cover opening 22 coinciding with the base plate opening 18. Edges of both ends 24A and 24B of the cover 20 in a Y direction include members bent to match the edges of the central part 12 of the base plate 10. On the other hand, both ends 26A and 26B of the cover 20 in an X direction include no members bent toward the base plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a holder for a filter such as a membrane filter, and is used when a sample attached to the filter after filtration or the like is analyzed using a microscope or spectroscopic analyzer. [Background technology]

[0002] Membrane filters with a wide variety of filter diameters and pore sizes are widely used in vacuum filtration to collect minute samples such as foreign matter and microplastics. Because the membrane filter is wet with liquid after collecting the sample, it must be dried to prevent wrinkles before analysis.

[0003] Conventionally, the wet filter after filtration is placed on a flat surface such as a glass plate to dry, and then the dry filter is transferred from the glass plate to a plate suitable for analysis, and the edges of the filter are fixed to the plate with adhesive tape to prevent wrinkles. However, this drying and fixing method is very time-consuming and labor-intensive.

[0004] For example, the filter holder in Patent Document 1 has a structure in which the filter is sandwiched between upper and lower members and fixed with screws, and the edge of the filter is fixed in a state where it is pulled in the outer circumferential direction by deformation of a leaf spring attached to the lower member. For example, the filter holder in Patent Document 2 has a structure in which the filter is fixed by being sandwiched between upper and lower umbrella-shaped members, and the edges of the filter are bent diagonally so that the edges of the filter are fixed in a state in which they are pulled in the outer circumferential direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-232774 [Patent Document 2] Patent No. 6518542 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when a wet filter is dried using the filter holders described in Patent Documents 1 and 2, the force acting on the filter increases, and there is a risk that the filter may break. An object of the present invention is to provide a filter holding method that is less likely to cause wrinkles in the filter during fixation and drying, and that prevents excessive force from being applied to the filter during the drying process, and also to provide a filter holder suitable for this method. [Means for solving the problem]

[0007] That is, the filter holder of the present invention is A filter holder comprising a base plate, a cover that covers a central portion of the base plate, and a magnetic member that fixes the base plate and the cover by magnetic force, wherein the central portion of the base plate is thinner and flatter than both end portions, a step is formed at the boundary between the central portion and both end portions, and a base plate opening is formed in the central portion, the cover overlaps a central portion of the base plate and has a cover opening aligned with the base plate opening; At the edges of both ends of the cover in a direction perpendicular to the direction connecting the both ends of the base plate (Y direction), members are provided that are bent toward the base plate so as to match the edges of the center of the base plate, The cover is characterized in that no member bent toward the base plate is provided on the edges of both ends of the cover in the direction (X direction) connecting both ends of the base plate.

[0008] The method for holding a filter of the present invention comprises the steps of: A method for holding a filter using the filter holder described above, comprising: the filter is wet; placing the filter in the center of the base plate so as not to protrude from the center and to cover the base plate opening; The edge of the cover that does not have a member bent toward the base plate is aligned with a step of the base plate, and the member bent toward the base plate is fitted into the edge of the center of the base plate, and the cover is placed on the base plate and fixed by magnetic force; The filter is dried in a state where the entire peripheral edge of the filter is sandwiched between the cover and the base plate.

[0009] In the above filter holder, it is preferable that the positions, sizes and shapes of both ends of the base plate are the same as the positions, sizes and shapes of both ends of a standard glass plate.

[0010] Furthermore, in the above filter holder, it is preferable that the cover is a metal plate having a thickness of 0.1 to 5 mm, and is removably fixed to the surface of the central part by magnetic force using the magnetic member fixed to the back surface of the central part of the base plate.

[0011] The filter holder of the present invention is A filter holder for total reflection measurement, comprising: a stainless steel base plate; a cover that covers a central portion of the base plate; and a magnetic member that fixes the base plate and the cover by magnetic force, a central portion of the base plate is thinner and flatter than both end portions, and a step is formed at the boundary between the central portion and both end portions; the cover overlaps the central portion of the base plate and has a cover opening at the center; At the edges of both ends of the cover in a direction perpendicular to the direction connecting the both ends of the base plate (Y direction), members are provided that are bent toward the base plate so as to match the edges of the center of the base plate, The cover is characterized in that no member bent toward the base plate is provided on the edges of both ends of the cover in the direction (X direction) connecting both ends of the base plate. [Effects of the Invention]

[0012] By using a filter holder configured in this way, when placing a wet filter in the center of the base plate and then placing a cover with an opening over it, the user can reliably position the cover with a single action. Specifically, by aligning the edge of the cover "where the bent member is not provided" with the "step" of the base plate, positioning in the X direction (the direction connecting both ends of the base plate) can be easily achieved. Also, by fitting the edge of the cover "where the bent member is provided" with the edge of the center of the base plate, positioning in the Y direction (the direction perpendicular to the direction connecting both ends of the base plate) can be easily achieved.

[0013] Without the "step" and "pair of bent members," the position of the cover opening relative to the filter would be inaccurate, and the filter would easily wrinkle when the cover was slid after it was placed on. With the "step" and "pair of bent members" of the present invention, the cover can be easily placed on the filter without wrinkling. Furthermore, since the cover is fixed to the center of the base plate by magnetic force, the filter can be clamped simply by placing the cover on. Furthermore, since the wet filter is placed on the flat surface in the center of the base plate and covered by the cover, it is fixed in place without applying any unnecessary force to the filter, and excessive force is not applied to the filter during the drying process.

[0014] An example of a filter to be held by the filter holder of the present invention is a membrane filter. It is suitable not only for filters that are prone to wrinkling, such as PTFE, but also for filters that break when bent, such as alumina. The filter holder of the present invention is designed so that the outer edge of the filter is sandwiched between the flat surface in the center of the base plate and the flat surface of the cover, which is fixed to it by magnetic force. This allows the filter to remain flat, and filters that are sensitive to bending can be easily held without damage.

[0015] As described above, by using the filter holder of the present invention, the dried filter can be set into a microscope or spectroscopic analyzer while still fixed in the filter holder, making it possible to easily and smoothly observe and analyze micro-samples attached to the filter. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is an exploded perspective view of the filter holder according to the first embodiment. [Figure 2] 1(A) to 1(C) are a front view, a side view, and a bottom view of the filter holder. [Figure 3] 1(A) to 1(D) are explanatory views of a method for holding a filter using the filter holder. [Figure 4] FIG. 10 is a diagram showing the state in which the filter holder of this embodiment is set in place of a standard glass plate on a holder for a microscope stage. [Figure 5] FIG. 10 is a diagram showing a filter holder for a large diameter filter according to a second embodiment. [Figure 6] FIG. 10 is a diagram showing a filter holder for total reflection measurement according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] First Embodiment An embodiment of the present invention will be described with reference to the drawings. The filter holder according to this embodiment is for transmission measurement and is used when analyzing a micro-sample attached to a filter by suction filtration or the like using a microscope (such as an observation microscope, an infrared microscope, a Raman microscope, a UV-Vis-NIR microscope, or an electron microscope) or a spectroscopic analyzer (such as a Fourier transform infrared spectrophotometer, a UV-Vis-NIR spectrophotometer, or a Raman spectrophotometer).

[0018] FIG. 1 is an exploded view of the filter holder. FIGS. 2(A) to 2(C) are plan, side, and bottom views of the filter holder. As shown in FIG. 1, the filter holder comprises a rectangular base plate 10, a metal cover 20 that covers a central portion 12 of the base plate, and a magnetic member 30 (see FIG. 2) that magnetically fastens the two together, and is configured to hold a filter 40 sandwiched between the central portion 12 of the base plate and the cover 20. Here, the explanation will be given using the mutually orthogonal X-Y-Z directions shown in FIG. 1.

[0019] The central portion 12 and both end portions 14A, 14B of the base plate 10 are aligned along the X direction in Fig. 1, and the central portion 12 is a flat surface that is thinner than the both end portions 14A, 14B. Steps 16A, 16B are provided at the boundaries between the central portion 12 and the both end portions 14A, 14B. These steps 16A, 16B may be formed straight and parallel to each other along the Y direction, as shown in Fig. 1, for example.

[0020] The flat surface of the central portion 12 need only be wide enough to accommodate, for example, a disk-shaped filter 40 without its outer periphery extending beyond the flat surface. A circular base plate opening 18 is formed in the flat surface of the central portion 12. The diameter of this base plate opening 18 is smaller than the diameter of the filter 40, and is formed so that when the filter 40 is placed on the flat surface, the outer periphery of the base plate opening 18 overlaps with the outer periphery of the filter 40, thereby covering the base plate opening 18 with the filter 40. A guide groove may be provided around the base plate opening 18 in the central portion 12 to mark the position where the filter 40 is to be placed.

[0021] The cover 20 has a size and shape that overlaps with and just covers the flat surface of the base plate 10. For example, as shown in Fig. 1, the cover 20 may be rectangular, with the length in the X direction of the cover 20 being the same as the distance between the two steps 16A, 16B, and the width in the Y direction being the same as the width of the flat portion of the central portion 12. As shown in Fig. 2(A), the cover 20 has a circular cover opening 22 that coincides with the base plate opening 18 on the flat surface when placed on the flat surface.

[0022] Edges 24A, 24B at both ends of cover 20 in the Y direction have members bent toward the base plate to align with the edges of the flat surface of base plate 10. In Fig. 1, edges 24A, 24B corresponding to the long sides of rectangular cover 20 are provided with members bent at 90 degrees along their entirety, but it is also possible to provide bent members only on parts of edges 24A, 24B corresponding to the long sides. In Fig. 1, a member bent at 90 degrees in the opposite direction is provided from the bent members. On the other hand, the edges 26A, 26B at both ends of the cover 20 in the X direction are not provided with a shape bent toward the base plate as described above.

[0023] Furthermore, the above-mentioned cover 20 can be formed, for example, from a metal plate having a thickness of 0.1 to 5 mm, and by making the height difference between the steps 16A and 16B of the base plate 10 approximately the same as the thickness of the cover 20, the surface of the filter holder can remain flat even after the cover 20 is placed on the base plate 10 as shown in Figure 2(B).

[0024] Furthermore, as a magnetic member for fixing the cover 20 to the flat surface of the base plate 10, a plurality of magnets can be fixed to the back surface of the central portion 12 as shown in FIG. 2(C).

[0025] Next, a method for holding a filter using the filter holder of this embodiment will be described with reference to Figures 3(A) to 3(D). The filter 40 used is, for example, a membrane filter with a wide variety of filter diameters and pore sizes, and is in a wet state after filtering a sample by suction filtration or the like. In this embodiment, for example, a filter with a diameter of 25 mm is used.

[0026] 3(A) and 3(B), the user first picks up the wet filter with tweezers or the like and places filter 40 in center portion 12 of the base plate so that it does not protrude from center portion 12 and covers base plate opening 18. Because filter 40 is wet, the entire peripheral edge of filter 40 sticks to the edge of base plate opening 18, making it less likely to wrinkle.

[0027] Immediately, cover 20 is placed on base plate 10 so that edge 26A (the edge without the bent member) at the end in the X direction of cover 20 is aligned with step 16A of base plate 10 and the bent members at edges 24A, 24B at both ends in the Y direction of cover 20 are fitted onto the edges of center portion 12 of the base plate. As a result, cover 20 is fixed to center portion 12 of the base plate by magnetic force, and the entire peripheral edge of filter 40 is sandwiched between them.

[0028] In this procedure, the user completes positioning in the X direction simply by aligning X-direction end 26A of cover 20 with step 16A of base plate 10, and also completes positioning in the Y direction by fitting both Y-direction edges 24A, 24B of cover 20 into the edges of center portion 12 of the base plate. Therefore, the user can reliably position cover 20 with a single action and can easily put cover 20 on filter 40 without causing wrinkles.

[0029] Finally, as shown in Figure 3(D), the filter holder is left in this state to dry the filter 40. Because the wet filter 40 is placed on the flat surface of the center portion 12 of the base plate and covered with the cover 20, it is fixed without applying any unnecessary force to the filter 40, and no excessive force is applied to the filter 40 during the drying process. The filter 40 can be dried not only by natural drying, but also by using heat or air in a constant temperature dryer or oven.

[0030] Furthermore, while a membrane filter is exemplified as filter 40, the filter is not limited to soft filters such as those made of PTFE, and may also be a filter that breaks when bent, such as alumina. The filter holder of this embodiment is structured so that the outer edge of filter 40 is sandwiched between the flat surface of center portion 12 of the base plate and the flat surface of cover 20, which is fixed thereto by magnetic force. This allows filter 40 to remain flat, and even filters that are sensitive to bending can be easily held without breaking.

[0031] In the filter holder of this embodiment, the position, size, and shape of both ends 14A, 14B of the base plate are the same as the position, size, and shape of both ends of a standard glass plate 90 as shown in Figure 4. This allows the user to directly set the dried filter holder in, for example, a microscope stage holder 60 as shown in Figure 4, allowing for a smooth start to observation and analysis using a microscope. Since the filter holder can be moved as is when performing measurements with different analytical instruments, sample transfer between analytical instruments becomes smooth, making it possible to easily and smoothly observe and analyze minute samples attached to the filter.

[0032] The microscope stage holder 60 in FIG. 4 is a common holder that can be attached to the stages of different types of microscopes, and the sample can be moved between different microscopes together with the holder 60.

[0033] Furthermore, as shown in Figure 4, the filter holder cover 20 is thin, and the surface of the filter holder is flat even when the filter 40 is clamped. This means that the distance from the microscope lens to the sample is short, meaning that even when using objective lenses of various magnifications, including objective lenses with a short working distance, the filter holder does not get in the way and microscopic measurements of the sample can be carried out smoothly.

[0034] FIG. 5 shows a filter holder for a large-diameter filter (e.g., 47 mm diameter) according to the second embodiment. The base plate central portion 12 and cover 20 are wider to accommodate the wider filter, but the basic configuration is the same as in the first embodiment. In particular, the position, size, and shape of both ends 14A and 14B of the base plate are the same as those of a standard glass plate, as in the first embodiment, ensuring compatibility when mounting the filter on, for example, a microscope stage holder 60. Furthermore, arc-shaped guide grooves 12A and 12B are formed around the base plate opening 18 in the base plate central portion 12 as markers for the position where the large-diameter filter should be placed, allowing the user to easily place the large-diameter filter in the center portion 12.

[0035] FIG. 6 shows a filter holder for total reflection measurement according to a third embodiment. It differs from the filter holder of the first embodiment in that the base plate 10 is made of stainless steel and is unpainted, and the central portion 12 does not have an opening. Furthermore, arc-shaped guide grooves 12A and 12B are formed in the central portion 12 of the base plate as markers for the position where the filter should be placed. The other configurations are the same as those of the first embodiment. By making the base plate 10 out of stainless steel, it becomes difficult to detect the paint on the base plate 10 or the material information of the base plate 10 itself during total reflection measurement. [Explanation of symbols]

[0036] 10 Base plate for transmission measurements 12 Central part 12A,B Guide groove 14A,B both ends 16A,B Step 18 Base plate opening 20 Cover 22 Cover opening 24A, BY direction edges at both ends 26A,BX direction both edges 30 Magnetic components 40 filters 50 Base plate for total reflection measurements Holder for 60 microscope stage 90 standard glass plates

Claims

1. A filter holder comprising: a base plate; a cover that covers a central portion of the base plate; and a magnetic member that fixes the base plate and the cover by magnetic force, a central portion of the base plate is thinner and flatter than both end portions, a step is formed between the central portion and both end portions, and a base plate opening is formed in the central portion; the cover overlaps a central portion of the base plate and has a cover opening aligned with the base plate opening; At both end edges of the cover in a direction perpendicular to a direction connecting both end edges of the base plate, members are provided that are bent toward the base plate so as to align with the edge of the center of the base plate, The cover has no bent members on both edges thereof in a direction connecting both ends of the base plate. A filter holder characterized by:

2. A method for holding a filter using the filter holder according to claim 1, the filter is wet; placing the filter in the center of the base plate so as not to protrude from the center and to cover the base plate opening; The edge of the cover that does not have a member bent toward the base plate is aligned with a step of the base plate, and the member bent toward the base plate is fitted into the edge of the center of the base plate, and the cover is placed on the base plate and fixed by magnetic force; A method for holding a filter, comprising drying the filter with the entire peripheral edge of the filter sandwiched between the cover and the base plate.

3. 2. The filter holder according to claim 1, wherein the positions, sizes and shapes of both ends of said base plate are the same as the positions, sizes and shapes of both ends of a standard glass plate.

4. In the filter holder described in claim 1, the cover is a metal plate having a thickness of 0.1 to 5 mm, and is removably fixed to the surface of the central part by magnetic force using the magnetic member fixed to the back surface of the central part of the base plate.

5. A filter holder for total reflection measurement, comprising: a stainless steel base plate; a cover that covers a central portion of the base plate; and a magnetic member that fixes the base plate and the cover by magnetic force, a central portion of the base plate is thinner and flatter than both end portions, and a step is formed at the boundary between the central portion and both end portions; the cover overlaps the central portion of the base plate and has a cover opening at the center; At both end edges of the cover in a direction perpendicular to a direction connecting both end edges of the base plate, members are provided that are bent toward the base plate so as to align with the edge of the center of the base plate, The cover has no bent members on both edges thereof in a direction connecting both ends of the base plate. A filter holder characterized by:

Images