Devices for filtering small quantities of liquid

Abstract

A device for filtering liquids is provided, comprising at least one first part and at least one second part, wherein the first part comprises a first volume and the second part comprises a second volume. wherein the first volume has a first opening to an upper surface and a second opening to a lower surface of the first part, wherein the second volume has a first opening to an upper surface and a second opening to a lower surface of the second part, and the second part has a filter that is located in the lower part of the second part. Furthermore, a method for filtering a liquid using the device is provided.

Description

[0001] The invention relates to a device for filtering small quantities of liquid, into which a liquid can be poured and in which a filter is arranged, and to a method for filtering liquids.

[0002] Devices for filtering small quantities of liquid are conventionally known as syringes with filters and cell sieves. In laboratory settings, pipettes are typically used to transport liquids. The corresponding liquid samples are drawn into the pipette and transferred to a device containing a filter or sieve.

[0003] Alternatively, a syringe with a filter can be used, although this changes the sequence of corresponding work steps. In this case, filter changes are time-consuming. Furthermore, state-of-the-art devices are often elaborately packaged, resulting in a significant expenditure of paper and plastic packaging materials.

[0004] The task is to provide an easy-to-use filter device that can be used with a pipette.

[0005] This problem is solved by a device according to claim 1 and a method according to claim 15. Further advantageous embodiments and configurations of the invention are described in the dependent claims, the figures, and the exemplary embodiments. The embodiments of the invention can advantageously be combined.

[0006] A first aspect of the invention relates to a device for filtering liquids, comprising at least a first part and at least a second part, wherein the first part comprises a first volume and the second part comprises a second volume. wherein the first volume has a first opening to an upper surface and a second opening to a lower surface of the first part, wherein the second volume has a first opening to an upper surface and a second opening to a lower surface of the second part, and the second part has a filter that is located in the area of ​​the second opening of the second part.

[0007] The device according to the invention advantageously enables the convenient transfer of liquids from a sample container into the device. This provides a user-friendly method for filtering liquids, which can be conveniently used with a pipette. Compared to the prior art, the device is material-efficient, simple, and robust in design, and enables a time-saving process.

[0008] The device incorporates a cavity. This cavity corresponds to the second volume. This cavity, with a capacity of up to 200 µl, can advantageously hold a suitable liquid, which is drawn into the device via a pipette inserted into the first part. This volume has the beneficial effect of providing a liquid reservoir from which a uniform liquid flow across the filter is possible. This allows the entire filter surface to be used for filtration. According to the invention, the liquid is collected below the device. The filtered liquid is intended for further use. The filtrate is discarded.

[0009] The device is dimensioned such that the lower part of the second section is compatible with a mini reaction vessel, e.g., an Eppendorf® tube with a volume of 1.5 to 2.0 ml, which is known to those skilled in the art. This allows the filtered liquid to be conveniently collected under the device for further use.

[0010] The device is further dimensioned such that a pipette tip can be inserted into the opening in the upper part of the first section. The area for inserting the pipette tip corresponds to the first volume. The device can be provided for various pipette sizes.

[0011] A further advantage of the invention is that the parts of the device, i.e., the first part and the second part, can be used separately. The second part can be combined with various first parts, each of which can be provided for different pipette tip sizes. Furthermore, the first part of the device can be used separately in combination with other commercially available filter devices. In this case, the first part must be provided in such a way that it is compatible with corresponding prior art filter devices.

[0012] Preferably, the first part of the device has a first connecting device in the region of the second opening, and the second part has a second connecting device in the region of the second opening, wherein the first and second devices are compatible with each other so that a stable connection between the first and second parts can be established. The devices advantageously enable a stable yet easily established connection. The first part overlaps the second part in the area of ​​the connection, such that the outer surface of the first part faces and / or is in contact with an inner surface of the second part. This advantageously enables stable contact between the first and second connecting devices and thus a stable connection between the first and second parts. The connection can be reversible. Reversible means that it can also be disassembled.The devices are designed in particular as a click mechanism, whereby the parts snap together and the connection can be released again by applying mechanical pressure. It is also possible for the two parts to be glued or welded together. In this case, the connection would be irreversible. The two-part design advantageously allows for the connection of differently sized first parts, i.e., first parts designed to hold pipette tips of different sizes, to the same second part.

[0013] Preferably, the first part of the device has a larger diameter in the region of the upper surface than in the region of the lower surface, with the transition between the diameters being gradual. The chamfered design enables a stopping function, in particular a clamping function, of the device when inserted into a mini reaction vessel, thereby allowing the use of reaction vessels with different diameters.

[0014] Preferably, the second part has a larger diameter in the region of the upper surface than in the region of the lower surface, and the transition between the diameters is gradual. This also advantageously provides a stop function for the device when it is inserted into a mini reaction vessel.

[0015] Preferably, the filter is an integral part of the second part of the device. This means that the filter is inserted into the second part during the manufacturing process of the device.

[0016] It is also preferred that the filter be glued or welded to the lower surface of the second part of the device.

[0017] Preferably, the device is made of an elastic plastic. In other words, the material is a synthetic polymer. An elastic plastic gives the device an elasticity that advantageously allows it to be pressed into a mini reaction vessel when inserted. Preferred polymers include polypropylene, polyethylene, and polyamide, but are not limited to these. Thermoplastic elastomers are particularly preferred. In particular, the thermoplastic elastomers exhibit an elasticity of 55A ± 20A, i.e., in the range of 35 to 75A. In a further preferred embodiment, the material can be silicone.

[0018] Preferably, the filter comprises a fabric made of polymeric filaments or a membrane. The filter material includes at least one polymer, e.g., polyethylene, polyethylene terephthalate, a polyamide, polyethersulfone, polytetrafluoroethylene, or polyvinylidene fluoride.

[0019] Furthermore, the lateral surface of the first and / or second part has a number of projections and grooves. These advantageously allow pressure equalization between the collection vessel and the environment during the filtration process, by allowing air displaced by the filtered liquid to escape laterally past the device through the grooves.

[0020] In a further preferred embodiment, the second part has a partition oriented perpendicular to the lower edge, so that the second volume is divided into a first sub-section and a second sub-section. This design allows air to escape from the immediate filter area. This immediate filter area corresponds to the first sub-section. The second sub-section is specifically intended for the air displaced from the first sub-section. This embodiment is particularly advantageous for devices with small-pore filter membranes, through which air can only escape slowly. It is particularly preferred that the partition is arranged such that liquid to be filtered, poured in from the direction of the first part, flows into the first sub-section of the second volume, and the second sub-section of the second volume remains unfilled with the liquid.The air can escape through the filter in the area of ​​the second sub-section.

[0021] In another preferred embodiment of the device, the first part and the second part are rigidly connected, so that the device is formed in one piece, and the filter is an integral part of the device. In this way, a stable filter device can advantageously be provided.

[0022] A second aspect of the invention relates to a method for filtering a liquid using a device according to the invention, comprising the steps: - Assembling the device, - Arranging the device in a collecting container, - Inserting a pipette into the upper opening of the first part, - Pouring a liquid from the pipette into the device, - Collecting the liquid in the collection container.

[0023] The advantages of the method correspond to the advantages of the device according to the invention.

[0024] The invention is explained in more detail using the figures. They show Fig. 1 A schematic top view of an embodiment of a device according to the invention. Fig. 2 a schematic top view of a first part of the device according to Fig. 1. Fig. 3 a schematic top view of a second part of the device according to Fig. 1. Fig. 4 a schematic representation in side view of the device according to Fig. 1 Fig. 5 a schematic representation in lateral view with an axis AA. Fig. 6 a sectional view along axis AA according to Fig. 5. Fig. 7 a section B of the representation according to Fig. 6. Fig. 8 a schematic representation of the first part of the device according to Fig. 2 in top view. Fig. 9 a schematic representation of the first part of the device according to Fig. 2nd view from below. Fig. 10 a schematic representation of the second part of the device according to Fig. 3 in top view. Fig. 11 a schematic representation of the second part of the device according to Fig. 3rd from the bottom. Fig. 12 a sectional view of a further embodiment of the device along the axis AA according to Fig. 5. Fig. 13 a schematic representation of the second part of the device according to Fig. 12 in top view. Fig. 14 a schematic representation of the second part of the device according to Fig. 12 seen from below. Fig. 15 a schematic representation of another embodiment of the device in a side view with an axis AA. Fig. 16 a sectional view along axis AA according to Fig. 15. Fig. 17 a flowchart of an embodiment of a method according to the invention.

[0025] An embodiment of a device 100 according to the invention Fig. 1 comprises a first part 1 and a second part 2. The device 100 is in Fig. Figure 1 is shown in a top view, i.e., viewed obliquely from above. The device 100 is designed for filtering a liquid.

[0026] The device is made of a thermoplastic elastomer with an elasticity of approximately 35 to 75 A. Examples of such materials include polypropylene and rubber. Other possible alternative or combined polymers are polyethylene and polyamides. Silicone is also a possible component.

[0027] The first part 1 has an upper surface 11 with a first opening 31, a lower surface 12 (see Fig. 2) with a second opening 32 (see Fig. 6) and a lateral surface 13. The lateral surface 13 is formed with projections 4 and grooves 5.

[0028] The first opening 31 of the first part is designed to receive the tip of a pipette, particularly a micropipette. The opening 31 can be sized to accommodate, for example, the tip of a 1 ml pipette, a 100 µl pipette, or a 10 µl pipette. The shape of the opening 31 can taper from the upper surface 11 towards the second opening 32 to precisely match the shape of the pipette tip to be inserted.

[0029] The first part 1 has a larger diameter in its upper region than in its lower region. The diameter decreases gradually from the upper surface 11 to the lower surface 12. The difference between the diameters of the upper surface 11 and the lower surface 12 can be 1 to 30%, preferably 5 to 25%, more preferably 10 to 20%, and most preferably 15%.

[0030] The second part 2 has an upper surface 21 with a first opening 33, a lower surface 22 with a second opening 34 (see Fig. 6) and a lateral surface 23. The lateral surface 23 is also formed with projections 4 and grooves 5. The device 100 is intended to be inserted into a commercially available microreaction vessel known to those skilled in the art, in which a liquid filtered by the device 100 is to be collected. The diameter of the second part 2 is smaller in the lower region, i.e., in the region of the lower surface 22, than in the upper region, i.e., in the region of the upper surface 21. The second part 2 also tapers gradually from the upper surface 21 to the lower surface 22. The difference between the diameter of the upper surface 21 and that of the lower surface 22 is not as pronounced as in the first part 1. The difference between the diameters of the upper surface 21 and the lower surface 22 is between 1 and 10%, preferably 5%. The taper of both parts is particularly evident in the side view shown. Fig. Figure 4 shows that the diameter of the second part 2 in the area of ​​the lower surface 22 is smaller than the inner diameter of a micro-reaction vessel into which the device 100 is to be inserted. The changing diameter towards the first part 1 allows the device 100 to gradually become stuck, in other words, to clamp itself in a micro-reaction vessel. The significantly wider design of the first part 1, whose diameter is wider, at least in the central lateral area 13, than the inner diameter of a corresponding micro-reaction vessel, thus provides a stop function that prevents the device 100 from sliding too far into the micro-reaction vessel.

[0031] Fig. 5 corresponds Fig. 4 with a drawn axis AA. Along this axis AA is in Fig. Figure 6 shows a section of the device 100. In the first part 1, a first volume 15 is formed, which is designed to receive a pipette tip. The shape of the first volume, which narrows from the first opening 31 to the second opening 32, is adapted to the shape of a pipette tip. In the second part 2, a second volume 25 is formed. A filter 6 is arranged in the region of the second opening 34 of the second part 2. The filter 6 is an integral part of the second part 2, i.e., the filter 6 is manufactured during the production of the second part 2 and is bonded to the rest of the material of the second part 2.

[0032] The filter 6 consists of a woven network of polymeric filaments, in particular polyethylene, but not limited to this. Other polymers, such as polyethylene terephthalate, a polyamide, polyethersulfone, polytetrafluoroethylene, or polyvinylidene fluoride, can be used alternatively or in combination with one another. Alternatively, the filter 6 can be a membrane made of the aforementioned materials. The pore sizes can be provided in different sizes depending on the desired purity level of the liquid to be filtered. The pore sizes of the filter 6 can therefore be in the range of 10 nm to 1 mm, preferably 10 nm to 1 µm, 10 nm to 500 nm, 20 nm to 250 nm, 100 nm to 5 µm, 1 µm to 1 mm, or 10 µm to 500 µm.

[0033] In Fig. In section 6, area B is circled in which the first part 1 is connected to each other by means of a first connecting device 14 and the second part 2 is connected to each other by means of a second connecting device 24. Fig. Figure 7 shows this area B cut out and enlarged. The connecting devices 14, 24 are designed such that the first part 1 is pressed into the first opening 33 of the second part 2 by pressure exerted from the direction of the first surface 11, and the first connecting device 14 engages below the second connecting device 24, i.e., "clicks" into place. This connection can be released again by mechanical pressure on the lateral area 23 of the first part 1.

[0034] In Fig. Figure 8 shows the first part 1 in a top view. The first opening 31 is formed in the center of the upper surface 11. The second opening 32 is shown in the center of the first opening 31. The side surface 13 has projections 4 and grooves 5.

[0035] In Fig. Figure 9 shows the first part 1 viewed from below. The second opening 32 is located in the center of the lower surface 12. The side surface 13 has projections 4 and grooves 5.

[0036] In Fig. Figure 10 shows the second part 2 in a top view. The first opening 33 is formed in the center of the upper surface 21. The filter 6 is arranged below the first opening 33 in the area of ​​the second opening 34 (not shown directly here). The side surface 23 has projections 4 and grooves 5.

[0037] In Fig. Figure 11 shows the second part 2 viewed from below. The second opening 34 is formed in the center of the lower surface 22, in which the filter 6 is arranged. The side surface 23 has projections 4 and grooves 5.

[0038] In Fig. Figure 12 shows a second embodiment of the device 100. Most of its features correspond to the representation of Fig. 6. In Fig. As a further feature, the device 100 has a partition 7, which is formed in the region of the second volume 25 of the second part 2. The first part 1 corresponds to the first embodiment according to Fig. 1. The circled section B also corresponds here Fig. 7.

[0039] The partition 7 divides the second volume 25 into a first subvolume 251 and a second subvolume 252. The partition 7 has a semicircular shape, which is Fig. 13 (top view of the second part 2) and in Fig. Figure 14 (view from below of the second part 2) shows the two subvolumes 251 and 252 connected to each other. The first subvolume 251 is the larger subvolume and is located directly below the second opening 32 of the first part 1. It is designed to hold the liquid to be filtered. The second subvolume 252 is the smaller subvolume and is designed to hold air displaced by the liquid, preventing it from interfering with the filtration process. The displaced air can escape from the second subvolume 252 through the membrane.

[0040] In Fig. Figure 15 shows a third embodiment of the device 100. In this embodiment, the device 100 is formed in one piece, i.e., the first part and the second part 2 are firmly connected to each other, i.e., made from a single piece, and thus irreversibly joined. Furthermore, this embodiment of the device 100 has the same features as the devices 100 according to Figure 15. Fig. 1 and Fig. 12, such as the external features of the projections 4 and the grooves 5.

[0041] In Fig. 16 is the device 100 according to Fig. The device 100 is shown in section 15 along axis AA. Here, too, it has a first volume 15 connected to the second volume 25. The second opening 32 of the first part 1 is identical to the first opening 33 of the second part 2, forming the transition from the first volume 15 to the second volume 25. In the area of ​​the second opening 34 of the second part 2, the filter 6 is attached to the lower surface 22, for example by gluing or welding.

[0042] Also in the embodiment according to Fig. 15 and Fig. 16 the second volume 25 may have a partition that divides it into two subvolumes (not shown).

[0043] In a procedure according to Fig. 17. A device according to one of the Fig. 1 to 16 are used for filtering a liquid. In a first step S1, the device 100 is assembled from the first part 1 and the second part 2, insofar as it is not a single piece according to Fig. 12 is provided. In a second step S2, the device 100 is placed in a collection vessel, e.g., a mini reaction vessel with a volume of 1.5 ml. In a third step S3, a pipette with a 1 ml tip is inserted into the first opening 31 of the first part 1. In a fourth step S4, a quantity of liquid 200 µl is dispensed from the pipette into the device. The liquid passes through the filter 6 and is collected in the mini reaction vessel in a fifth step. Reference symbol list 1 first part 11 upper surface of the first part 12 lower surface of the first part 13 lateral surface of the first part 14 Connecting device of the first part 15 first volume 2 second part 21 upper surface of the second part 22 lower surface of the second part 23 lateral surface of the second part 24 Connecting device of the second part 25 second volume 251 first subsection of the second volume 252 second sub-section of the second volume 31 First opening of the first part 32 second opening of the first part 33 First opening of the second part 34 second opening of the second part 4 protrusions 5 grooves 6 filters 7. Septoplast 100 Device

Claims

[1] Device (100) for filtering liquids comprising at least one first part (1) and at least one second part (2), wherein the first part (1) comprises a first volume (15) and the second part (2) comprises a second volume (25), wherein the first volume (15) has a first opening (31) to an upper surface (11) and a second opening (32) to a lower surface (12) of the first part (1), wherein the second volume (25) has a first opening (33) to an upper surface (21) and a second opening (34) to a lower surface (22) of the second part (2), and the second part (2) has a filter (6) which is arranged in the area of ​​the second opening of the second part (2). [2] Device (100) according to claim 1, wherein the first part (1) has a first connecting device (14) in the region of the second opening (32), and the second part (2) has a second connecting device (24) in the region of the first opening (31), and wherein the first device (14) and the second device (24) are compatible with each other, so that a stable connection between the first part (1) and the second part (2) can be established. [3] Device (100) according to one of the preceding claims, wherein the first part (1) has a larger diameter in the region of the upper surface (11) than in the region of the lower surface (12), and the transition between the diameters is gradual. [4] Device (100) according to one of the preceding claims, wherein the second part (2) has a larger diameter in the region of the upper surface (21) than in the region of the lower surface (22), and the transition between the diameters is gradual. [5] Device (100) according to one of the preceding claims, wherein the filter (6) is an integral part of the second part (2). [6] Device (100) according to any one of claims 1 to 4, wherein the filter (6) is glued or welded to the lower surface (22) of the second part (2). [7] Device (100) according to one of the preceding claims, wherein the material of the device (100) comprises an elastic plastic. [8] Device (100) according to claim 7, wherein the material comprises a thermoplastic polymer. [9] Device (100) according to one of the preceding claims, wherein the filter (6) comprises a fabric of polymeric filaments or a membrane. [10] Device (100) according to one of the preceding claims, wherein the lateral surface (13) of the first part (1) and / or the lateral surface (23) of the second part (2) has a number of projections (4) and grooves (5). [11] Device (100) according to one of the preceding claims, wherein the second part (2) has a partition (7) oriented perpendicular to the lower surface (22), such that the second volume (25) is divided into a first sub-area (251) and a second sub-area (252). [12] Device (100) according to claim 11, in which the partition (7) is arranged such that liquid to be filtered, which is filled in from the direction of the first part (1), flows into the first sub-region (251) of the second volume (25), and the second sub-region (252) of the second volume (25) is not filled with the liquid. [13] Device (100) according to one of the preceding claims, wherein the first part (1) and the second part (2) are firmly connected, so that the device (100) is formed in one piece, and the filter (6) is an integral part of the device (100). [14] Method for filtering a liquid using a device (100) according to any one of claims 1 to 13, comprising the steps: - Assembling the device (100), - Arranging the device (100) in a collecting vessel, - Inserting a pipette into the upper opening of the first part (1), - Pouring a liquid from the pipette into the device (100), - Collecting the liquid in the collection container.

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