Device for filtering

Abstract

A device for filtering a liquid, comprising a container (110) for holding the liquid (10), wherein the liquid (10) contains at least one solid substance (10a), and wherein the container (110) is formed with a first fastening part (110a) on a side surface (110b) of the container (110), a filter unit (120) that is axially displaceable in the container (110) to form an airtight seal with at least a part of the container, wherein the filter unit (120) is formed with a second fastening part (120a) on a side surface (120b) of the filter unit (120) that coincides with the first fastening part (110a), and a filter medium (130) that is impermeable to the solid substance (10a) in the liquid (10), wherein the filter medium (130) is provided at a lower end or on a side wall of the filter unit (120),so that the liquid (10) flows through the filter medium (130) and enters the filter unit (120) when the filter medium (130) is forced into the container (110), , characterized in that at least a portion of an inner side surface (110b) of the container (110) is configured such that at least a portion of an outer side surface (120b) of the filter unit (120) slides frictionally axially over the inner side surface (110b) of the container (110) and forms an airtight seal with the inner side surface (110b) of the container (110) when the filter unit (120) is pushed into the container (110); and in that the fastening parts (110a, 120a) are screw threads, so that the filter unit (120) is lowered in the container (110) by the screw action, so that the pressure required to filter or separate the components (10a, 10b) in the liquid (10) is exerted by means of the fastening action, so that the liquid (10) flows through the filter medium (130) while the solid substance (10a) is pressed downwards towards the inner bottom surface (110c) of the container (110).

Description

AREA OF REVELATION

[0001] The present disclosure relates to liquid filtration, more particularly to an apparatus and method for filtering a liquid and keeping the filtrate separate. BACKGROUND

[0002] In the modern medical world, it has become increasingly important to analyze a physiological fluid, such as blood, urine, and the like. For this purpose, it is necessary to separate or filter one or more solid substances from the fluid.

[0003] Two different conventional arrangements for filtering the liquid are described in the Fig. 7a - 7b shown. In Fig. Figure 7a illustrates a typical filtration approach, wherein the liquid is held in an upper container (20) comprising a filter medium (40) and a piston (50). The piston (50) exerts pressure on the liquid. Since the filter medium (40) is only permeable to a liquid (10), a solid substance (10a) contained in the liquid (10) is retained in the upper container (20) while the liquid (10) flows through the filter medium (40) and is collected in a lower container (30). However, there is a high probability that the solid substance (10a) will form a blocking layer on the filter medium (40). Therefore, the piston (50) must exert external pressure to force the liquid (10) to flow through the solid substance (10a) and the filter medium (40).

[0004] In Fig. Figure 7b illustrates a reverse filtration approach in which a lower container (30) holds the liquid and an upper container (20) is configured as a syringe with a piston (50) and a filter medium (40) in an outlet at an open bottom of the upper container (20). During filtration, the outlet is immersed in the liquid in the lower container (30). As the piston (50) is raised, a liquid (10) flows through the filter medium and is collected in the upper container (20), while a solid substance (10a) settles at a bottom of the lower container (30). Although this arrangement effectively minimizes clogging, transferring the collected liquid (10) from the upper container (20) to another container is difficult and therefore requires special arrangements. Furthermore, there is a high probability that the liquid (10) will be retained in the lower container (30).

[0005] Numerous modern systems have been developed to separate components in a liquid. For example, centrifugation is a technique for separating components from a solution by applying a centrifugal force based on their size, shape, density, viscosity of the medium, and rotor speed. This method can separate two miscible substances and analyze the hydrodynamic properties of macromolecules.

[0006] US Patent No. 4,154,690 A discloses an apparatus for use in the centrifugal separation of components of a liquid. The apparatus comprises a separating element that can be slid into a cylindrical container containing the liquid. While the container is subjected to centrifugation, a portion of the container in contact with the separating element bends to allow the liquid to flow through a space between the separating element and the bent portion, and to allow the separating element to slide to a bottom of the container.

[0007] PCT patent application no. PCT / DK2010 / 050056 discloses a device for extracting a sample from a collection medium with increased yield compared to centrifugation techniques. After centrifugation, a solution is subjected to two or more filtering processes to separate the sample from the collection medium. However, there remains interest in providing improved and alternative devices to those currently widely available.

[0008] European patent EP 2 268 252 B1 shows a filter cylinder with a piston, the cylinder having a wall with a closed bottom and an open top, and a hollow, tubular piston therein. The piston has a distal end covered by a cap having a proximal cap seal that extends outwardly to engage the walls of the cylinder and form a fluid-tight seal with the cylinder during use. The distal end of the piston has a piston flange that extends outwardly and is adjacent to a recess in the piston such that the cap forms a snap fit over the piston flange and extends into the recess. The piston flange causes the cap to bulge outwardly sufficiently to form a fluid-tight seal with the cylinder during use.A filter is inserted into the bottom of the cap and rests against an inwardly extending lip of the cap.

[0009] US patent application US 5 077 012 A shows a device for collecting biological fluids and for storing samples taken from a biological fluid for qualitative and quantitative testing. The device comprises a tubular container open at both ends, with a quantitative testing storage unit removably attached to one end of the tubular container. The quantitative testing storage unit has an open end, a cytology membrane mounted in the storage unit, and a retaining rib. Slidably mounted within the tubular container is a shuttle assembly comprising a cylindrical hollow piston defining a chamber, a thumb cover covering one end of the piston, and a fluid flow opening formed in the piston, as well as a qualitative sample container assembly removably attached to the piston.The container assembly for qualitative samples comprises a clip-on membrane assembly with a membrane containing immobilized antibodies and a filter housing attached to the clip-on membrane assembly. The filter housing is designed to be inserted into the storage unit for quantitative testing after being slidably transported along the tubular container by the piston.

[0010] Therefore, there is a need in the art for a device for filtering a liquid and retaining the filtrate in a simple, efficient, and cost-effective manner. There is also a need for a device for filtering a liquid without requiring a driven actuator to apply pressure for filtering, while minimizing clogging of a filter medium. SUMMARY

[0011] The present disclosure proposes an apparatus and method for filtering a liquid and retaining the filtrate in a simple, efficient, and cost-effective manner. The apparatus performs reverse filtration without using a driven actuator to apply pressure for filtering, while minimizing clogging of a filter medium.

[0012] The device comprises a container, a filter unit, and a filter medium. The container contains the liquid containing at least one solid substance. The filter unit is axially movable within the container. The filter medium is provided at a lower portion of the filter unit and is impermeable to the solid substance in the liquid.

[0013] According to one embodiment, when the container is pushed into the filter unit, the liquid flows through the filter medium and enters the filter unit. The container is formed with a first fastening part, and the filter unit is formed with a second fastening part that coincides with the first fastening part. When the container and the filter unit are attached to each other, the liquid flows through the filter medium and is retained in the filter unit.

[0014] The fastening parts together form a mechanical fastening element, namely a threaded fastening element.

[0015] According to one embodiment, the filter medium is removably attached to a bottom of the filter unit.

[0016] According to the invention, at least a portion of an inner side surface of the container is configured such that at least a portion of an outer side surface of the filter unit slides frictionally axially over the inner side surface of the container to form an airtight seal with the inner side surface of the container when the filter unit is pushed into the container. Furthermore, the solid substance in the liquid is disposed between a bottom surface of the filter medium and an inner bottom surface of the container when the container and the filter unit are attached to each other.

[0017] According to an alternative embodiment, the filter unit includes an upper region and a lower region, wherein the filter medium is embedded in a side wall of the lower region.

[0018] According to a further embodiment, the lower region of the filter unit is attached to the upper region of the filter unit in an axially displaceable manner.

[0019] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments together with the accompanying drawing figures, in which like numerals represent like components. BRIEF DESCRIPTION OF THE ACCOMPANIMENTAL DRAWINGS

[0020] In the figures, similar components and / or features may have the same reference numerals. Furthermore, different components of the same type may be distinguished by following the reference numerals with a second numeral that distinguishes between the similar components. If only the first reference numeral is used in the description, the description applies to each of the similar components with the same first reference numeral, regardless of the second reference numeral. Fig. 1 shows an exploded perspective view of the device according to a first embodiment of the present invention. Fig. 2 shows a longitudinal sectional exploded view of the device according to a first embodiment of the present invention. Fig. Figure 3 shows a longitudinal sectional view of the device during use according to a first embodiment of the present invention. Fig. Figure 4 shows a longitudinal sectional view of the device during use according to a first embodiment of the present invention. Fig. Figure 5 shows a longitudinal sectional view of the device during use according to a first embodiment, not according to the invention. Fig. 6 shows a perspective exploded view of the device according to a first embodiment, not according to the invention. Fig. 7a - 7b show longitudinal sectional views of two different conventional arrangements for filtering a liquid. Fig. Figure 8 shows a longitudinal sectional view of the device during use according to a second embodiment of the present invention. Fig. 9 shows a longitudinal sectional view of the device with a lower portion of a filter unit in an extended position according to a third embodiment of the present invention. Fig. 10 shows a longitudinal sectional view of the device with a lower portion of a filter unit in a folded position according to a third embodiment of the present invention. Fig. 11 shows a longitudinal sectional view of the device with a rod in an upper position according to a fourth embodiment of the present invention. Fig. Figure 12 shows a longitudinal sectional view of the device with the rod in a lower position according to a fourth embodiment, not according to the invention. DETAILED DESCRIPTION

[0021] According to the present disclosure, a device for filtering a liquid is provided, which will now be described with reference to the embodiments shown in the accompanying drawings. The embodiments do not limit the scope and range of application of the disclosure. The description relates solely to the embodiments and their proposed applications.

[0022] The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiment in the following description. Descriptions of well-known components and processes are omitted so as not to unnecessarily obscure the embodiments contained herein. The examples used herein are intended merely to facilitate understanding of the manner in which the embodiments herein may be practiced and to further enable those skilled in the art to practice the embodiment herein. Accordingly, the description should not be construed to limit the scope of the embodiment contained herein.

[0023] The following description of the specific embodiment will disclose the general nature of the embodiments herein so fully that others, by applying current knowledge, can easily modify, adapt, or embody the same for various applications of this specific embodiment without departing from the generic concept. Therefore, such adaptations and modifications should be understood to be within the meaning and range of equivalents of the disclosed embodiments. It is understood that the phraseology or terminology used herein is for the purpose of description and not of limitation.

[0024] Various terms used herein are defined below. To the extent that a term used in a claim is not defined below, it should be given the broadest definition given to that term by persons in the relevant art, as reflected in printed publications and issued patents at the time of filing. Definitions:

[0025] Filtration: A process of separating one component from another or from a mixture of multiple components. Reverse filtration: A process in which a filtrate is forced to move in a direction other than that of gravity.

[0026] Solid substance: Any natural or synthetic substance in solid or powder form. The present disclosure relates to a device. Those skilled in the art would appreciate that various embodiments of the present disclosure enable filtering of the liquid and retaining the filtrate in a simple, efficient, and cost-effective manner without the need for a driven actuator, e.g., a pump, to apply filter pressure while minimizing clogging of a filter media.

[0027] The present invention performs reverse filtration, forcing the filtrate to flow through the filter medium in a direction other than gravity while forcing the residue in the opposite direction, thus minimizing the likelihood of clogging in the filter medium without compromising filtrate quality. Furthermore, the pressure required to filter the liquid is exerted by the fastening action, thereby simultaneously filtering and collecting the filtrate in the filter unit while preventing remixing of the filtrate with the residue located between the container and the filter unit.

[0028] With reference to the accompanying drawings, Fig. 1 is an exploded perspective view of the device according to a first embodiment of the present invention. The device (100) comprises a container (110) and a filter unit (120) that is axially displaceable within the container (110). The two containers (110) and the filter unit (120) are formed from a rigid material, e.g., plastic, metal, ceramic, cellulose fibers, and the like.

[0029] As in Fig. 2, the container (110) contains the liquid (10) containing at least one solid substance (10a, in Fig. 3). The liquid (10) can be any bodily fluid such as blood, urine, milk, tears, mucus, saliva, semen, sweat, pus, etc. In an alternative embodiment, the liquid can be water, a beverage, oil, a chemical compound, a food, a drug, and the like. The beverage includes, but is not limited to, coffee, tea, juice, soup, alcoholic beverages, carbonated beverages, etc.

[0030] A filter medium (130) is provided at a bottom of the filter unit (120), wherein the filter medium (130) is for the solid substance (10a, in Fig. 3) is impermeable in the liquid (10). The filter medium can be a single-layer filter medium such as a sieve, a porous membrane, etc., a multi-layer porous filter pack such as a filter medium disclosed in US Patent US 8,679,218 B2, or any other commercially available filter medium. In a multi-layer filter pack, each layer has at least one pore or hole, and the layers are arranged such that the pores or holes of each layer are smaller than those of an immediately lower layer. The filter medium (130).

[0031] In an exemplary embodiment, the filter medium (130) is formed as the bottom wall of the filter unit (120). However, in any other embodiment, the filter medium (130) can be removably attached to a bottom wall of the filter unit (120). Furthermore, the filter medium (130) can be removably attached to a top or bottom side of the bottom wall of the filter unit (120).

[0032] The container (110) includes a first fastening part (110a), and the filter unit (120) includes a second fastening part (120a) that mates with the first fastening part (110a). According to the invention, the fastening parts (110a, 120a) are screw threads, and the container (110) and the filter unit (120) can be fastened to each other by a screwing process. In other exemplary embodiments, the fastening parts (110a, 120a) can also be designed as other mechanical fastening elements, e.g., snap fasteners, press-in fasteners, hook-and-loop fasteners, and the like, as shown in the Fig. 5, Fig. 6, Fig. 11 and Fig. 12 is displayed.

[0033] In the first embodiment, the first fastening part (110a) is formed on an inner side surface (110b) of the container (110), and the second fastening part (120a) is formed on an outer side surface (120b) of the filter unit (120). However, both fastening parts (110a, 120a) may be formed on the outer side surfaces of the container (110) and the filter unit (120), as shown in Fig. 4, with an inverted lip portion of the filter unit (120) such that the fastening parts (110a, 120a) are aligned in register with each other when the filter unit (120) is pushed into the container (110).

[0034] Furthermore, the first fastening part (110a) and the second fastening part (120a) can also be formed as a projection around a lip portion of the container (110) or two or more inverted projections around a lip portion of the filter unit (120), as shown in the Fig. 5 and Fig. 6. The fastening parts (110a, 120a) together form a snap lock, so that the first fastening part (110a) engages in the second fastening part (120a) when the filter unit (120) is pushed into the container (110).

[0035] Returning to Fig. 3, the device (100) separates the liquid (10) and the solid substance (10a) when the container (110) and the filter unit (120) are attached to each other. While the container (110) and the filter unit (120) are attached to each other, the liquid (10) flows through the filter medium (130) and enters the filter unit (120). Furthermore, the solid substance (10a) is between a bottom surface (130a, shown in Fig. 2) of the filter medium (130) and an inner bottom surface (110c, in Fig. 2) of the container (110) when the container (110) and the filter unit (120) are attached to each other. In a first embodiment, the solid substance (10a) is a powder.

[0036] The inner side surface (110b) of the container (110) and the outer side surface (120b) of the filter unit (120) are configured such that the filter unit (120) is automatically aligned with respect to the container (110) as the filter unit (120) is slid into the container (110). A cross-section of the container (110) and the filter unit (120) may be circular, triangular, polygonal, or have another shape that allows for proper alignment between the container (110) and the filter unit (120) when the filter unit (120) is to be substantially slid into the container (110).

[0037] Furthermore, the configuration of the inner side surface (110b) of the container (110) and the outer side surface (120b) of the filter unit (120) allows a portion of the outer side surface (120b) of the filter unit (120) to be frictionally pushed axially into the inner side surface (110b) of the container (110) to form an airtight seal between the inner side surface (110b) of the container (110) and the outer side surface (120b) of the filter unit (120). For example, the inner side surface (110b) of the container (110) and / or the outer side surface (120b) of the filter unit (120) is formed with an O-ring to form a sealing contact between the inner side surface (110b) of the container (110) and / or the outer side surface (120b) of the filter unit (120).

[0038] Furthermore, a negative pressure is created between the filter unit (120) and the container (110), so that the solid substance (10a) adhering to a bottom side of the filter medium (130) is forced to fall into the container (110) when the filter unit (120) is detached from the container (110). Thus, a cleaning process of the filter medium (130) is simplified.

[0039] In the first embodiment, the inner side surface (110b) of the container (110) is contoured such that an upper region (110e, in Fig. 2) of the inner side surface (110b) of the container (110) is wider than a lower region (110d, in Fig. 2) of the inner side surface (110b) of the container (110). An inner diameter of a lower portion (110d, shown in Fig. 2) of the container (110) is at least equal to an outer diameter of the bottom of the filter unit (120), so that the bottom of the filter unit (120) is frictionally engaged axially within the inner side surface (110b) of the lower region (110d, in Fig. 2) of the container (110) and forms the airtight seal with the inner side surface (110b) of the container (110).

[0040] This configuration allows a lower end of the filter unit (120) to be located in the upper area (110e, in Fig. 2) of the container (110) can move essentially freely and begins to frictionally engage axially in the lower region (110d, in Fig. 2) of the inner side surface (110b) of the container (110). Although in the above embodiments, a distance between two ends of a side wall of the container (110) and the filter unit (120) is mentioned as an inner diameter and an outer diameter, respectively, it should be understood that it also refers to a width when non-cylindrical or non-conical containers and filter units are used.

[0041] It is understood that the figures are for informational purposes only and are not to scale with the actual device. In a preferred embodiment, the upper region (110e, in Fig. 2) of the container (110) is conically shaped and the lower portion (110d, in Fig. 2) of the container (110) is cylindrically shaped, wherein: i. a maximum inner diameter of the conical portion is 43.263 millimeters (mm); ii. a minimum inner diameter of the conical area is 33 mm; iii. an inner diameter of the cylindrical portion is 33 mm; iv. a length of the conical portion is 57.981 mm; and v. a length of the cylindrical portion is 17.412 mm.

[0042] Furthermore, the filter unit (120) is formed in a shape similar to the container (110), except for an additional crown area, wherein: a. a maximum outer diameter of the conical area is 35.127 mm; b. a minimum outer diameter of the conical area is 31.124 mm; c. an outer diameter of the cylindrical portion is 31.124 mm; d. the outer diameter of the crown area is 48.5 mm; e. a length of the conical portion is 53.91 mm; f. a length of the cylindrical portion is 16.33 mm; and g. a length of the crown area is 19 mm.

[0043] Furthermore, the lower area (110d, in Fig. 2) of the inner side surface (110b) of the container (110) and / or the outer side surface (120b) may be coated with a material that does not react with the liquid (10) in order to avoid erosion due to repeated sliding movements between the container (110) and the filter unit (120).

[0044] The complete filtering process performed by the device (100) is as follows: The liquid (10) to be filtered is collected in the container (110), wherein the liquid (10) contains the solid substance (10a). The liquid (10) is permeable through the filter medium (130), and the solid substance (10a) in the liquid (10) is impermeable through the filter medium (130).

[0045] The lower end of the filter unit (120) is inserted into an upper end of the container (110). Since the outer diameter of the lower end of the filter unit (120) is at least equal to the inner diameter of the lower region (110d, in Fig. 2) of the container (110), an airtight seal is formed between the outer side surface (120b) of the filter unit (120) and the inner side surface (110b) of the lower portion (110d) of the container (110) when the lower end of the filter unit (120) is inserted into an upper end of the lower portion (110d, in Fig. 2) of the container (110).

[0046] The filter unit (120) is further lowered in the container (110) by pressing the filter unit (120) or by the fastening action, e.g. screwing action, so that the liquid (10) flows through the filter medium (130), while the solid substance (10a) is directed towards the inner bottom surface (110c, in Fig. 2) of the container (110) is pressed downwards. The pressing or fastening process is continued until no further fastening is possible in order to hold the liquid (10) in the filter unit (120) and to press the solid substance (10a) between the bottom surface (130a) of the filter medium (130) and at the same time the inner bottom surface (110c, in Fig. 2) of the container (110).

[0047] Since the pressure required to filter or separate the components (10a, 10b) in the liquid (10) is exerted by means of the fastening action, the present invention eliminates the need for a driven actuator and therefore reduces the complexity and cost of manufacturing and operating the device (10). The present invention performs reverse filtration, whereby the solid (10a) is forced to a bottom of the container (110) and the liquid (10) is forced to flow through the filter medium (130) in a vertically upward direction, as shown in Fig. 3. This avoids the need for an actuator to force the filtrate, while simultaneously preventing clogging of the filter medium. Furthermore, the container (110) and the filter unit (120) are attached to each other to collect the liquid (10) and the solid substance (10a) in the container (110) and the filter unit (120), respectively, thereby simultaneously separating and collecting the components (10a, 10b) without the use of an actuator, e.g., a piston, while preventing remixing of the liquid (10) with the solid substances (10a).

[0048] Although in the above embodiments it is shown that the filter medium (130) forms a bottom of the filter unit (120), it is also possible to provide the filter medium on a side wall of the filter unit (120), as in Fig. 8. In this embodiment, the filter medium (130) is embedded in the side wall of the filter unit (120) near the bottom of the filter unit (120) such that the bottom of the filter unit (120) is in contact with the inner bottom surface (110c) of the container to minimize the likelihood of the liquid (10) remaining in the container (110).

[0049] Fig. Figure 9 shows a longitudinal sectional view of the device according to a third embodiment of the present invention. In this embodiment, the filter unit (120) includes an upper portion (120c) and a lower portion (120d) axially slidably mounted at a lower end of the upper portion (120c). The lower portion (120d) is movable between an extended position and a folded position (in Fig. 10). This configuration allows for complete separation of the liquid (10) and the solid substance (10a), even if the amount of the solid substance (10a) present in the liquid is unknown.

[0050] In this embodiment, a side wall of the bottom portion (120d) is embedded in the filter medium (130) so that liquid (10) flows into the bottom portion in a direction perpendicular to the direction of gravity. Since a bottom surface of the bottom portion (120d) forms the inner bottom surface (110c, in Fig. 2) of the container (110), there is no likelihood of the liquid (10) becoming trapped between the container (110) and the filter unit (120). Furthermore, the entire bottom region (120d), including the bottom wall and the side wall of the bottom region (120d), can be embedded in the filter medium (130) to allow flow of the liquid (10) from both the bottom and the sides of the bottom region (120d). In this way, it is possible to completely separate the components (10a, 10b) while preventing clogging and / or remixing of the components (10a, 10b).

[0051] Fig. 11 shows a longitudinal sectional view of the device according to a fourth embodiment of the present invention. In this embodiment, the filter unit (120) comprises a fastening part (210), a guide part (220), and a rod (230) with a handle (231). The fastening part (210) is designed as a circular ring that can be removably attached to the container (110). The guide part (220) is attached to the fastening part (210) via one or more connectors such that the guide part (220) forms a center point of the fastening part (210). The guide part (220) contains a hole (not shown), and the rod (230) extends through the hole.

[0052] The rod (230) is formed with a thread that mates with the thread formed in the hole of the guide member (220), and the rod (230) is movable between an upper position and a lower position. An upper end of the rod (230) is attached to a handle (231), and a lower end of the rod (230) is attached to the filter medium (130), so that the filter medium (130) is urged into the container (110) when the rod (230) is moved to the lower position, as shown in Fig. 12 shown.

[0053] An edge of the filter medium (130) is configured such that the filter medium (130) is frictionally axially extended over the inner side surface (110b, in Fig. 2) of the container (110) and forms an airtight seal with the inner side surface (110b, in Fig. 2) of the container (110) when the filter medium (130) is forced into the container (110).

[0054] According to the exemplary embodiment, the method for filtering the liquid using the Fig. 2 & 3. The method comprises the following steps: collecting the liquid (10) in the container (110), wherein the liquid (10) contains the solid substance (10a), and filtering the liquid (10) using the filter medium (130) which is impermeable to the solid substance (10a) in the liquid (10). For filtering, the filter medium (130) is positioned over an upper surface of the liquid (10) and moved from the upper surface to the inner bottom surface (110c) of the container (110) so that solid substance (10a) is moved downwards and the liquid (10) flows through the filter medium (130).

[0055] As the filter medium (130) is moved, a sealing contact is formed between a peripheral edge of the filter medium (130) and the inner side surface (110b) of the container (110). Furthermore, the filter medium (130) is moved toward the inner bottom surface (110c) of the container (110) until further movement is stopped and blocked by the solid substance (10a).

[0056] While the solid substance (10a) is pressed toward a bottom of the container (110), the liquid (10) is forced to flow vertically upward through the filter medium (130). This prevents clogging of the filter medium (130), while simultaneously separating and collecting the liquid (10) and the solid substance (10a), and preventing remixing of the liquid (10) with the solid substance (10a).

[0057] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may also include the plural forms unless the context clearly indicates otherwise.

[0058] The terms “comprises,” “comprising,” “including,” and “having” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.

[0059] The use of the term "at least" or "at least one" suggests the use of one or more elements, as the use may be made in any of the embodiments to achieve one or more of the desired tasks or results.

[0060] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be developed without departing from its basic scope. The scope of the invention is determined by the following claims. The invention is not limited to the described embodiments, versions, or examples, which are included to enable one of ordinary skill in the art to make and use the invention when combined with information and knowledge available to one of ordinary skill in the art.

Claims

[1] A device for filtering a liquid, comprising a container (110) for holding the liquid (10), wherein the liquid (10) contains at least one solid substance (10a), and wherein the container (110) is formed with a first fastening part (110a) on a side surface (110b) of the container (110), a filter unit (120) which is axially displaceable in the container (110) to form an airtight seal with at least a part of the container, wherein the filter unit (120) is formed with a second fastening part (120a) on a side surface (120b) of the filter unit (120) which corresponds to the first fastening part (110a), and a filter medium (130) which is impermeable to the solid substance (10a) in the liquid (10), wherein the filter medium (130) is provided at a lower end or on a side wall of the filter unit (120),so that the liquid (10) flows through the filter medium (130) and enters the filter unit (120) when the filter medium (130) is forced into the container (110), characterized by , that at least a portion of an inner side surface (110b) of the container (110) is configured such that at least a portion of an outer side surface (120b) of the filter unit (120) slides frictionally axially over the inner side surface (110b) of the container (110) and forms an airtight seal with the inner side surface (110b) of the container (110) when the filter unit (120) is pushed into the container (110); and in that the fastening parts (110a, 120a) are screw threads, so that the filter unit (120) is lowered in the container (110) by the screw action, so that the pressure required to filter or separate the components (10a, 10b) in the liquid (10) is exerted by means of the fastening action, so that the liquid (10) flows through the filter medium (130) while the solid substance (10a) is pressed downwards towards the inner bottom surface (110c) of the container (110). [2] The device of claim 1, wherein the filter medium (130) is removably attached to the lower end of the filter unit (120). [3] Device according to claim 1, wherein the filter medium (130) is formed as the lower end of the filter unit (120). [4] The device according to claim 1, wherein an inner diameter of a lower portion (110d) of the container (110) is at least equal to an outer diameter of the lower end of the filter unit (110), so that the lower end of the filter unit (120) frictionally slides axially within the inner side surface (110b) of the lower portion (110d) of the container (110) and forms the airtight seal with the inner side surface (110b) of the container (110) when the filter unit (120) is urged into the lower part (110d) of the container (110). [5] The device of claim 1, wherein the filter medium (130) is a single-layer filter medium. [6] The device of claim 1, wherein the filter medium (130) is a multi-layer filter pack. [7] The device according to claim 1, wherein the filter unit (120) comprises an upper portion (120c) and a lower portion (120d) axially slidably mounted at a lower end of the upper portion (120c). [8] Device according to claim 7, wherein the filter medium (130) is embedded in a side wall of the bottom portion (120d) of the filter unit (120). [9] The device according to claim 7, wherein the lower portion (120d) of the filter unit (120) is narrower than the upper portion (120c) of the filter unit (120). [10] The device according to claims 4 and 7, wherein an inner diameter of the lower portion (110d) of the container (110) is at least equal to an outer diameter of a lower end of the upper portion (120c) of the filter unit (120), such that the lower end of the upper portion (120c) of the filter unit (120) frictionally slides axially within the inner side surface (110b) of the lower portion (110d) of the container (110) and forms the airtight seal with the inner side surface (110b) of the container (110). [11] The device according to claim 1, wherein at least a portion of the inner side surface (110b) is coated with a material. [12] Device according to claim 11, wherein the material is non-reactive with the liquid (10). [13] Device according to claim 1, wherein the filter medium (130) is forced into the container (110) by a sliding movement of the filter unit (120).

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