Filter device comprising bionic filter element, and method for separating microplastic from fluids

Abstract

The invention relates to a bionic device and to a method for separating microplastic from a fluid. The device consists of at least one housing and at least one filter element or at least one self-supporting filter element which has a gill-shaped design, wherein the fluid enters the housing and the filter element or the self-supporting filter element at one end via an inlet opening, and the separated microplastic accumulates at the other end as retentate by means of a circular flow within the filter element and can be discharged or suctioned centrally in the region of the filter element via a retentate drain or can be collected in a container and removed. The housing and the filter element or the self-supporting filter element have an opening angle relative to the inlet opening of a « 90° in order to generate the circular flow and are designed to be at least partly conical, the filter element at least partly has a lattice-shaped or porous filter structure, and the fluid exits laterally through the lattice-shaped or porous filter structure of the filter element and through the filtrate drain.

Description

[0001] Filter device comprising a bionic filter element and method for separating microplastics from fluids

[0002] The invention relates to a bionic device and a method for separating microplastics from a fluid, wherein the device consists of at least one housing and at least one filter element or at least one self-supporting filter element which is gill-shaped and the fluid enters at one end via an inlet opening into the housing and the filter element or the self-supporting filter element and at the other end the separated microplastics accumulate as retentate through a circular flow within the filter element and can be drained or sucked off centrally in the region of the filter element via a retentate outlet and can be collected and removed in a container, wherein the housing and the filter element or the self-supporting filter element have an opening angle to the inlet opening of a « 90° to generate the circular flow and are at least partially conical in design,wherein the filter element at least partially has a mesh- or pore-shaped filter structure and the fluid exits laterally through the mesh- or pore-shaped filter structure of the filter element.,

[0003] It is now widely known that microplastics can have negative impacts on organisms and the environment. To achieve a short- and medium-term reduction in microplastic emissions, technical innovations are needed that can be quickly and cost-effectively integrated into existing production chains. A particular focus here is on new filter technologies that could be implemented as early as possible at the "entry pathways" for microplastics into the environment, for example in washing machines. Each wash cycle can emit 124 to 308 mg of synthetic microfibers per kg of laundry. These synthetic fibers are referred to as microplastics and, at 77 g per capita per year, rank 10th in total emissions in Germany. Globally, synthetic fibers rank first, ahead of other sources of microplastics such as tire wear or microplastics in cosmetics. Wastewater treatment plants can only partially capture these fibers.

[0004] Common state-of-the-art filters mostly use so-called dead-end filtration with a filter medium on whose surface a filter cake builds up that must be removed at regular intervals, such as in filter coffee machines (replacement of the filter element, shaking, backwashing). Dead-end filters are generally suitable for removing microplastics, but must be professionally cleaned at relatively short intervals and, if necessary, returned to the manufacturer. Flotation and cyclone-based separation, as currently used in wastewater, are not suitable for the targeted removal of microplastics because the very similar density of liquid and solids makes these separation processes difficult to apply. Cross-flow filtration requires high pumping pressure with fine membranes and is used in nano- and ultrafiltration, but not in wastewater with solids sizes of up to 1 mm.A number of filter devices and filter methods are known from the state of the art, but they have the disadvantages mentioned above.

[0005] EP 4041429 A1 describes a separator for separating microplastics from wastewater, comprising a chamber with an inlet and an outlet, a sieve structure forming a permeable barrier between the inlet and the outlet, and a washing device for washing the sieve structure, wherein the sieve structure comprises a first mesh within the chamber.

[0006] WO 2022023953 A1 shows a filter device for liquids, consisting of a container and at least one filter which is removably accommodated in the other container, wherein the filter consists of a filter pack comprising a first, structurally rigid layer adapted to the pressure of the liquid and a second layer which is structurally soft in order to filter micro-contaminants without hindering the flow of the liquid and without giving in to the pressure.

[0007] US 2022154385 A1 covers methods, apparatus, and washing machines that involve the filtration of microparticles from liquid wastewater from laundry appliances and systems. Thus, wastewater is withdrawn from the outlet of an external tub of the washing machine, and a continuous high-pressure condition is created, which comprises at least a portion of the collected liquid wastewater through a pumping device. A threshold amount of high-pressure liquid is forced through a microparticle filter system by means of a sensor using a pumping device. WO 2022084677 A1 describes a microparticle filter suitable for filtering microparticles from wastewater from a textile treatment device. The filter comprises a filter chamber consisting of chamber walls, an inlet, and an outlet. The filter also comprises a filter medium contained in the filter chamber, such that microparticles are filtered from the wastewater.The filter consists of a filter residue collection chamber, the chamber walls consisting of an opening and a movable element, and the element can be moved back and forth between a first and a second configuration.

[0008] DE 102020207163 A1 relates to a filter device for filtering microplastics, comprising a housing with a main flow path with a first filter element and a secondary flow path with a second filter element, wherein the first filter element is arranged above the second filter element.

[0009] WO 2021116933 A1 describes a compactor for automatically extracting and compacting microplastics from waste water, wherein the compactor is arranged with an inlet having at least one plate within the chamber which can be moved between a non-compressing position and a compressing position and a drive unit for driving the at least one plate and a discharge outlet arranged so that compressed microplastics can be automatically discharged.

[0010] EP 4041458 A1 discloses a separator suitable for separating microplastics from wastewater and comprising a chamber with an inlet line and an outlet line, the chamber having a baffle that is coaxial with the casing and projects upwards from the lower end of the chamber.

[0011] EP 4041429 A1 describes a separator for separating microplastics from wastewater, comprising a chamber with an inlet and an outlet, a sieve structure forming a permeable barrier between the inlet and the outlet, and a washing device. The washing device comprises a channel connected to a first set of fixed guides located around one end of a first mesh to guide the washing liquid over the first mesh. US 4696797 A shows a liquid suspension separator comprising a housing with a separation chamber with a filter body that laterally filters the particles of the suspension from the liquid component. The housing comprises elution, liquid suspension, and outlet openings, and the liquid component of the suspension can be collected.

[0012] EP 4037804 A1 discloses a device for filtering water, comprising a filter forming a permeable container for the liquid to be filtered, an actuating inlet for providing a water flow, a filter liquid inlet for providing the liquid to be filtered to the filter, and a rotatable cleaning structure for cleaning the filter, wherein the structure comprises at least one scraper. The scraper is rotatably mounted with respect to the first surface of the filter and has at least one rotatable element arranged to receive the water flow.

[0013] CN 214990829 U shows a quick separation device for microplastics in marine sediments, which comprises 5 separation cylinders, wherein the first separation cylinder has a vertical section which is connected to the vertical section at the upper part of the second separation cylinder by a connecting line and filters seawater via a first filter sieve in the connecting line.

[0014] EP 3676439 A4 discloses a method for cleaning waste water from a washing machine comprising a microfiber filter unit having a number of stacked filter layers held in place by a frame arrangement.

[0015] US 11045843 B2 shows a device for removing fibers from an aqueous solution, wherein there is a central rod having an upper end, a middle part and a lower end and a plurality of discs each having a central opening, which are shaped to fit on the central rod and have a plurality of arms, each of the plurality of arms extending from the central opening to an outer end on a plane which is substantially orthogonal with respect to the central rod.EP 1528139 A2 describes a device for cleaning fabrics comprising a container for the relative movement of the fabric to be cleaned, a means for introducing a working fluid to the container, a cross-membrane filter, a compressor-driven refrigeration system and a heat exchanger with a coolant side and a pump to move the working fluid from the container through the working fluid side of the heat exchanger and then through the filter means.

[0016] US 2022154385 A1 discloses a washing machine with a hydrocyclone and filtration hybrid system. Fibers that break off during the washing process are passed through the hydrocyclone to be separated from the wastewater. The fibers separated from the wastewater, along with the water remaining in a tub at the end of the pumping process, are transferred to the microfilter structure located behind a detergent dispenser. The fibers are retained by the filter structure to release the purified water into the tub and drain it away.

[0017] WO 2023 / 172344 A1 describes a method for improved, more efficient, or more effective filtration of materials, such as microplastics, from liquids. A vortex filter provides vortex cross-flow filtration. The vortex filter has a tapered spiral configuration, which can be conical or even conical-helical. At the bottom of the vortex filter is a collection container through which a continuous flow of fluid flows, collecting the microplastics and allowing them to be removed.

[0018] DE 102021207442 A1 discloses a surface filter that is intended to be a further development of a so-called Sanderson filter. Two flow paths are provided in the filter housing, with a first flow path conducting a fluid with a smaller proportion of microfibers laterally through the filter structure, while a second flow path runs essentially along a central longitudinal axis, along which residues from the first flow path can be entrained toward the outlet and prevent clogging of the filter. WO 2013 / 184814 A1 shows a Sanderson filter.In this, a fluid containing solids, for example wastewater from algae cultivation facilities, is introduced into a cylindrical structure along the longitudinal central axis. The curvature of ribs or baffle-shaped elements within the cylindrical structure allows a portion of the fluid containing solids to pass through slots into the wall area of ​​the cylindrical structure, where it is retained or filtered by the walls. The filtered fluid can exit laterally through holes on the outer surface of the cylindrical structure. Any remaining wastewater flows from one end of the filter to the other along the longitudinal central axis within the cylindrical structure, with any remaining solids being entrained in the flow path and the filter not clogging.

[0019] DE 19748233 A1 discloses a filter device for solids, particularly coarse dirt, from wastewater. The wastewater is initially accelerated helically via an inlet and a subsequent spiral channel. A vortex is generated along a filter element below the inlet, which presses the solids contained in the wastewater against the wall of the filter element. Solids-free wastewater can exit the filter element through openings located laterally in the filter element. The remaining solids can be moved along the filter element in the direction of flow to the outlet and continuously deposited in a solids container or a sedimentation basin.

[0020] Finally, US 4003837 A discloses a self-cleaning filter in a cooling system of a ship, in which a rotating screw in a cylinder transports cooling water, whereby any solids in the cooling water are crushed via sieve-like holes in the cylinder in order to prevent damage to the cooling system during the cooling process.

[0021] The problem to be solved here is that solids contained in a fluid, in particular microplastics in wastewater, can be separated in a continuous process by a device and that the device can be cleaned during operation of this device so that the separation process takes place without clogging and as much microplastics as possible can be collected in a container with as little water as possible.

[0022] The problem is solved here by the features of independent claims 1 and 12.

[0023] According to the invention, a bionic device is used to separate solids, in particular microplastics, from a fluid. The term "bionic" was chosen here to clarify that a special geometry of the housing and the filter element can be derived from plankton-filtering fish. Thus, in a special embodiment of the housing and / or filter element, an arched and / or gill-shaped design is provided, which mimics the gill arch shape of the fish. Furthermore, the angle in the conical filter element is based on the angle examined in the fish's gill net system.

[0024] For the purposes of this application, microplastics are understood to mean solids or small plastic particles with a diameter of less than 5 mm (5000 micrometers). Even smaller plastic particles, ranging in size from 1 to a maximum of 1000 nm, are referred to as nanoplastics. However, for the purposes of this invention, the distinction between microplastics and / or nanoplastics is not made precisely, since the solid or microplastic size in a fluid is often not clearly determinable. The purification of the fluid also depends, among other things, on the pore size of the filter element. Thus, the term solids or microplastics refers here to both microplastic and nanoplastic particles, which can in particular also include nanoplastics and microplastics as well as nanoplastic and microplastic fibers.The nano- and microplastics can also include solids other than nanoplastic or microplastic particles, such as nano- and microplastic fibers, as long as they are dispersed in the fluid.

[0025] The term "fluid" refers to liquids and gases in which solids are transported in a dispersion-like manner. Furthermore, the device comprises at least one housing and / or at least one filter element, into which the fluid enters at one end via an inlet opening in the housing and / or the filter element. At the other end, the separated solids accumulate as retentate within the filter element through a circular flow and can be drained or removed centrally in the area of ​​the filter element.

[0026] For this purpose, the housing and / or the filter element can be designed at least partially conically to generate the circular flow, wherein the filter element at least partially has a mesh- or pore-shaped filter structure and the fluid can escape laterally through the mesh- or pore-shaped filter structure of the filter element.

[0027] The filter structure tapers conically from the inlet to the outlet (opening angle α < 90°). The separation of solids from the fluid is achieved by a modification or adaptation of cross-flow filtration, which can be referred to as semi-cross-flow filtration. In this process, the purified fluid flows laterally through the filter element (filtrate), while the solids inside the filter element are increasingly concentrated from the inlet to the outlet. They can then be drained, extracted, or collected and removed as a mixture of substances (retentate) with a high solids content in the central area of ​​the filter element.

[0028] The hydrodynamically optimized inlet opening and the filter element, which tapers in the direction of flow, create a circular flow. The conical shape of the filter element allows the microplastics or particles to roll along the filter element. Separation tasks for various solids and particles can be easily achieved by adapting the filter element and / or the filter fabric. Experiments or trials can underline the solution to such a task. A semi-cross-flow filtration system enables the solids to be concentrated as retentate at the filter element outlet. The solids can be drained, suctioned off, or removed through an opening in the central area of ​​the filter element. This eliminates the need to remove the filter element for cleaning, for example, and requires little user interaction when removing the retentate or cleaning the filter element.Nevertheless, a container for the retentate can be emptied regularly.

[0029] The filter structure tapers conically from the inlet to the outlet (opening angle a ≤ 90°), advantageous in the range of a = ≤ 40°, and particularly advantageous in the range of a = ≤ 20°. The hydrodynamically optimized inlet and the filter element, including the filter fabric, tapering in the direction of flow, create a circular flow. The conical shape of the filter element allows the microplastics or particles to roll along the filter element.

[0030] The inlet opening of the bionic filter element can be surrounded by a housing into which the filter element is fitted. The housing can therefore represent the outer shell of the bionic filter element. However, it is also possible for the filter element itself to comprise the frame structure of the filter element, in other words to be self-supporting. The housing and / or the filter element can be at least partially conical or at least partially concave. A part of the housing or the filter element can have a spindle-shaped, spiral-shaped, or partition-like insert or an adapter-like shape. The spindle-shaped, spiral-shaped, or partition-like insert or spindle-shaped, spiral-shaped, or partition-like adapter can also be integrated into the filter element or into a separately arranged prechamber.

[0031] The fluid containing the solids flows along the insert in the pre-chamber or in the housing of this shape and is set into a helical, circular or circular motion as it flows into the filter element. However, it is also possible for the spindle-shaped, helical or partition-like insert or spindle-shaped, helical or partition-like adapter to be arranged in a housing separate from the housing and / or filter element and to be connected to the housing and / or filter element via a connection, for example a flange, in the area of ​​the inlet opening or at a distance from the inlet opening. The spindle-shaped, helical or partition-like insert or spindle-shaped, helical or partition-like adapter can also be integrated into the pre-chamber.

[0032] The inlet opening of the bionic filter element can also be surrounded by a pre-chamber into which the fluid containing the solids is initially directed before the fluid containing the solids passes along the spindle-shaped, helical, or partition-like shape into the filter element. The pre-chamber can therefore be part of the housing and / or the filter element, or it can be located upstream of the housing and / or the inlet opening of the filter element, as is the case with the spindle-shaped, helical, or partition-like insert or spindle-shaped, helical, or partition-like adapter as part of the pre-chamber. However, it is also possible for the pre-chamber to essentially represent part of the housing and / or the filter element. In this respect, it is also possible for the pre-chamber to be part of the housing and / or the filter element and to be formed integrally with the housing and / or the filter element.In the case of a separate arrangement, the pre-chamber can be connected to the housing and / or filter element via a connection, for example a flange in the area of ​​the inlet opening or at a distance from the inlet opening.

[0033] The filter element itself exhibits a rigidity that largely resists tensile, shear, bending, and / or torsional forces. This is important so that the filter element can maintain a consistently conical or at least concave shape, which resists helical, circular, or circular motion of the fluid containing the solids within the filter element. The filter element must also be able to withstand the fluid pressure containing the solids.

[0034] The housing and / or the filter element, whether as an insert or a cantilevered element, can be designed with ribs or gills. This type of housing and / or filter element construction can be chosen to save material during the manufacturing of the housing and / or filter element.

[0035] The filter element has a mesh or pore-shaped filter structure, which ensures that the fluid can escape from the mesh or pore-shaped filter element and that the solids remain within the filter element. When arranged as an insert in the housing, the filter element can be individually removed and / or washed.

[0036] The mesh or pore-shaped filter structure of the filter element includes mesh or pore sizes from 20 μm to 500 μm, with openings preferably between 50 μm and 100 μm. The choice of mesh or pore size depends on the size of the solids to be filtered and the flow rate or pressure of the fluid containing the solids.

[0037] The filter element with the mesh or porous filter structure is usually made of stainless steel. However, it is also possible for the filter element to consist of a plastic or plastic fabric as the filter structure, whereby the mesh or porous filter structure can be made of the same or different materials as the filter element. The housing is also usually made of stainless steel, but like the filter element, it can also be made of plastic or plastic fabric. It is also possible for the filter element to have load-bearing or supporting elements, which can be rib- or arch-shaped, for example, and which support or permeate a mesh-, porous, or fabric-like filter structure.

[0038] Furthermore, the filter device has a multi-way outlet through which the fluid and / or the retentate can be periodically or continuously drained, sucked off, or removed from the filter device. The fluid laterally exiting the bionic filter element can be returned to the fluid circuit or water or wastewater circuit via an outlet without solids. The retentate, i.e. the solids remaining in the area of ​​the filter element or the microplastic particles that are generally located within the filter element and / or suspended in the fluid within the filter element, i.e. have not yet sunk to the bottom, can be drained off via a valve, in particular a check valve at the bottom of the filter element, sucked off, and / or collected continuously or sequentially via a solids container into a container belonging to or downstream of the bottom of the filter element, and then removed.The retentate can be collected in a container and removed from the container, which can be made of stainless steel or plastic. However, it is also possible to directly convey the retentate by sending it to further technical processing, such as a centrifuge, to separate any fluid adhering to the retentate or to subject it to further filtration. Furthermore, the retentate can also flow into a press, which can compress the retentate and remove any remaining fluid from the retentate. The shape of the container is variable and depends on the specific design of the bionic device, in particular the filter element and / or the housing surrounding the filter element.

[0039] The bionic device can have an analog or digital control mechanism, according to which the quantity, strength, i.e., the speed or pressure, and the temperature of the fluid inlet into the bionic device are regulated. The helical flow within the filter element can also be generated or at least supported by the quantity, speed, and / or pressure and / or temperature of the fluid inlet. The control mechanism can also ensure the interruption of the fluid inlet and / or the drainage or suction of the microplastics or solids from the area of ​​the filter element in general, for example, the microplastics still suspended in the fluid or the microplastics already at the bottom of the filter element.

[0040] The control mechanism allows the solids to be removed from the filter element area, enabling continuous or periodic cleaning of the fluid through the bionic filter element. This also includes generating a backflow into the fluid near the bottom of the filter element, so that any solids adhering to the filter element walls can be removed, drained, or suctioned off. The induced backflow can thus be used to clean the filter element.

[0041] The control mechanism can be designed as a valve, flap, screen, or hydrodynamic resistance and can control the opening or closing of a valve unit, flap assembly, screen, or hydrodynamic resistance. The control mechanism can control or comprise one or more valves, flaps, screens, or hydrodynamic resistances.

[0042] For example, one control mechanism can be arranged in the area of ​​the retentate outlet and another in the area of ​​the filtrate outlet. The control mechanism regulates, for example, the switching of valves and is intended to create a suction / negative pressure with turbulent flow in the area of ​​the filter element. This becomes stronger if, for example, a valve in the area of ​​the filtrate outlet closes while, for example, a valve in the area of ​​the retentate outlet opens. When the retentate valve opens, for example, the particles still suspended within the filter element in general and / or in the fluid within the filter element and / or the microplastics or microparticles already located in the area of ​​the base of the filter element are sucked away or drained away and can be collected in a container and then removed.

[0043] The control mechanism thus determines the cleaning interval, i.e., how often or at what intervals, for example, the retentate valve is opened, and the cleaning duration, i.e., how long, for example, the retentate valve is open. At the same time, by simultaneously or staggering the closure of the filtrate valve, the control mechanism can apply a pressure pulse to the wall of the filter element in order to detach microplastics or particles adhering to the filter element wall. The control mechanism thus backwashes the outer wall of the filter element in the form of a pressure pulse, thereby detaching microplastics or particles adhering to the filter element wall with the retentate fluid.

[0044] Furthermore, cleaning or backwashing can also be achieved by using the control mechanism in the area of ​​the filtrate outlet to force fresh water against the filter element via a hose that is attached, for example, to the filtrate outlet. Backwashing with fresh water can be pulsed or continuous. Cleaning with fresh water is preferably carried out when, for example, the filtrate valve and the retentate valve are closed. As with backwashing with filtrate fluid, the microplastics or particles are released from the filter structure. When the control mechanism in the area of ​​the retentate outlet is opened, the microplastics or particles thus released are sucked away or drained away along with the microplastics or particles already present in the filter element before cleaning or backwashing. They can be collected in a container and then removed.The cleaning of the filter element by backwashing can also be carried out by alternating filtrate fluid and / or fresh water in order to make cleaning as effective and cost-effective as possible.

[0045] The control mechanism typically regulates a cleaning interval within a range of 13s to 86s and a cleaning duration within a range of 0.6s to 6.5s. However, the interval and duration can be variably adjusted to include longer or shorter cleaning intervals or durations.

[0046] For example, if the retentate valve is closed, microplastics adhering to the inner wall of the filter element in the area of ​​the filter element or the filter structure can be detached from the filter structure by the pressure pulse triggered on the outer wall of the filter element, for example by briefly closing and then reopening the filtrate valve. When the retentate valve is opened, they can be removed or sucked away along with the microplastic particles already present within the filter element. The detached microplastic particles can thus be sucked away or sucked away along with the particles already suspended within the filter element in general or in the fluid within the filter element and / or with the particles already present in the area of ​​the base of the filter element, and collected in a container for subsequent removal.However, it should be noted that a pressure pulse to detach adhering microplastics or particles is optional, meaning it can be performed, but is not mandatory. The filter element can also be cleaned with the filtrate valve open, for example, by the control mechanism opening the retentate valve and draining or extracting the retentate without the filtrate valve having to be closed.

[0047] It has been shown that up to 97% of the microplastics or particles used can be recovered or collected as retentate, with over 80% of this remaining outside the filter in the retentate container. A short cleaning time allows the fluid volume in the retentate container to be reduced to approximately 5%. This facilitates subsequent cleaning / treatment of the highly concentrated retentate.

[0048] To improve filtration and cleaning performance, additional sensor monitoring can be implemented, e.g., via the pressure differential across the filter element, which is connected to the control mechanism. If the sensor detects that a large amount of microplastics or particles is accumulating in the filter and the filter element is at risk of clogging, the control mechanism can activate the valves, flaps, sieves, or hydrodynamic resistors, and cleaning can be performed. The cleaning interval can therefore be adjusted flexibly depending on the filter's load.

[0049] The design of the bionic device is selected so that flange connections are present in the area of ​​the inlet opening. These can also be present in the area of ​​the housing or the filter element or the pre-chamber and are intended to provide a tight connection between the area of ​​the inlet opening into the filter element and the housing or the pre-chamber. The pre-chamber can, for example, be designed as a two-part structure with the housing and / or the filter element, or the pre-chamber can be designed as a single piece with the housing, or only the housing can be designed as a single piece with the filter element. In all possible variations, the two-part or multi-part structure and the single-piece structure of the housing, the pre-chamber and the filter element, with or without an insert or adapter, are paramount. All possible variations are claimed as part of the invention, but not all of them are listed exhaustively here.

[0050] To achieve improved purification of the fluid containing solids, several bionic devices or filter elements can be arranged or connected in series. These can all have the same or different designs with regard to the arrangement of the filter element, the shape of the insert or adapter, the housing, or the pre-chamber. Thus, several filter elements can also be arranged in one housing. Likewise, the other elements mentioned in the previous designs, such as a housing with or without an insert or adapter, or a pre-chamber with or without an insert or adapter, can be present in one or more housings or devices arranged together or separately from one another, so that the purification of the fluid containing solids is improved.

[0051] The bionic device may also include a vent and / or a siphon to ensure the drainage of the fluid and prevent odor pollution in the environment.

[0052] The present invention also discloses a method for separating solids, in particular microplastics, from fluids, wherein the fluid enters a filter element via an inlet opening, generates a circular flow within a filter element by means of an at least partially conical design, wherein the filter element at least partially has a mesh or pore-shaped filter structure and then the fluid exits laterally through the mesh or pore-shaped filter structure of the filter element and the solids can be drained off or sucked off as retentate in the region of the bottom of the filter element or a container arranged there, which can be a separate part or a component of the filter element, and can be collected and removed.

[0053] The opening angle of the housing and / or filter element relative to the inlet opening is less than a = « 90°, advantageously less in the range of a = « 40°, particularly advantageously less in the range of a = « 20°. The choice of opening angle depends on various parameters such as the type of fluid, the type of solids, the flow velocity, the pressure and / or temperature of the fluid. The aforementioned parameters can, individually or in combination, determine the size of the opening angle relative to the inlet opening in order to enable optimal separation of the solids from the fluid. This applies in particular to the selection of the insert or adapter as part of the pre-chamber for forming the circular flow.The insert or adapter, as part of the pre-chamber or as an external part without a pre-chamber, can individually or in conjunction with the aforementioned parameters contribute to determining the size of the opening angle relative to the inlet opening and generating optimal circular flow and / or achieving fluid filtration. The choice of insert or adapter inside or outside the pre-chamber thus also contributes to generating circular flow in the filter element. The selection of the insert or adapter, or the parameters, is also important for the arrangement of the remaining components of the bionic device, such as the housing, the pre-chamber, and the filter element, either as a separate element or as part of the housing or the filter element of the bionic device.

[0054] For example, for smaller solids, lower pressure, or lower flow velocities, the filter element requires a smaller opening angle at the inlet of the filter element (< 40°) to ensure easier sinking or rolling of the solids along the wall areas of the filter element and thus better separation of the solids from the fluid. The same considerations also apply when changing the size of the solids, the type of fluid, the pressure, and / or the flow velocity as parameter variations.

[0055] The considerations regarding the design of the opening angle mentioned in the above example can be applied to all device and parameter variations in order to avoid clogging of the filter structure and to improve the separation of solids from the fluid.

[0056] It can therefore be stated that the circular flow of the fluid containing the solids can be determined by selecting the aforementioned parameters and / or the choice of insert or adapter for generating a circular flow. It is not important whether the insert or adapter is part of the housing of the filter element, the pre-chamber, or the housing, or is arranged separately; rather, by generating a circular flow within the filter element, an optimized separation of solids and fluid can be achieved. The fluid and / or the retentate can be drained or removed from the bionic device periodically or continuously. This is done by means of an analog or digital control mechanism that drains or extracts the retentate from the area of ​​the filter element.After the solids have been removed from the filter element area, solids can be stirred up or removed from the filter element by inducing backflow with filtrate fluid to prevent clogging of the filter structures. This bionic device is intended for use in water remediation, wastewater treatment, and food processing, particularly for removing microplastics from dishwasher or washing machine wastewater. However, other applications are also possible, so the above-mentioned possible uses are intended to be exemplary and not exhaustive.

[0057] Example

[0058] In order to prove the cleaning mechanism by the control mechanism, some tests were carried out to demonstrate the efficiency of the device and the process.

[0059] A siphon was formed with the filtrate outlet pipe, and valves were installed as control mechanisms in the retentate and filtrate outlets. The flow rate was provided with a spiral-shaped pre-chamber. The control mechanism comprised two automatic valves located near the filtrate and retentate outlets to clean the filter element at specific intervals. The filtrate outlet and the retentate outlet were opened for 0.6 s and 1.3 s, respectively, when 10 l and 20 l passed through the filter element. The cleaning effect on the flow rate was tested using plastic flock fibers (0.1 g / l), as this combination most closely resembles the application in washing machines. 10 l were filtered, and the filter element was cleaned after 5 l and 10 l. This process was repeated five times. Between each test, the test bench was rinsed with clean water, and the filter element was manually washed to remove any remaining particles.

[0060] Before each new test, the control mechanism closed the valves, filled the filter element with clean water and vented it, and mixed 20 liters of tap water, 0.5 g of flock fibers, and 5 ml of liquid detergent. The control mechanism opened the valve near the filtrate outlet to start the test. Cleaning was automatically stopped when 5 liters and 10 liters passed through the filter element. After the second cleaning, the test was stopped, and the control mechanism closed the valves.

[0061] After each experiment, three samples were taken: 1) the total volume of concentrate, 2) one liter of filtrate and 3) all fibers remaining in the filter element, i.e. the retentate (MR), which was resuspended in a maximum of one liter, separating the mass fractions of microparticles from the water using a suction filter with round filter papers.

[0062] In all tests with flock fibers (N = 43), the particle content in the concentrate was 64.1 ± 24.1% and in the retentate 33.2 ± 24.4%. On average, only 2.7 ± 3.2% of the fibers were not retained by the filter element and entered the filtrate. This means that up to 97% of the fibers are separated by the filter, with over 80% of the fibers in the retentate container being retained outside the filter. This avoids or at least delays interruption of the filtration process to clean the filter element. The best filter efficiency results from a specific combination of inlet, filter element size and angle, mesh size, and cleaning cycle.

[0063] Periodic cleaning can prevent the filter element from becoming clogged. Cleaning increases the volume flow of a fiber suspension compared to a non-cleaned filter fabric. This effect can be even more pronounced if the cleaning frequency is increased.

[0064] The invention is explained in more detail with reference to the following figures:

[0065] Figure 1 shows the bionic device 1 in a schematic side view. It is schematically indicated that a fluid (upper arrow) enters a pre-chamber 11. Below the pre-chamber 11 there is a housing 2 into which the fluid flows from the pre-chamber 11 and on which a vent 12 is arranged. Within the housing 2 there is a filter element 3 (not shown) through which the fluid flows. The fluid flow or the concentration of the solids in container 7 is regulated via a control mechanism 8. In the area of ​​the vertical fluid outlet there is a siphon 10 which serves, among other things, to regulate the fill level in the housing 2.

[0066] Figure 2 shows a filter element 3 with an inlet opening 4, a filter structure 5 and the opening angle 6. The filter structure 5 tapers conically from the inlet opening 4 to the outlet opening in the central lower region of the filter element 3. The opening angle 6 can be in the range a = 90°, advantageously in the range of a = 40°, particularly advantageously in the range of a = 20°. The hydrodynamically optimized inlet opening 4 and the filter element 3, including the filter structure 5, which tapers in the direction of flow, generate a circular flow or intensify or continue a rotating helical preferential movement already induced by a pre-chamber 11 (not shown).The conical shape of the filter element 3 enables the particles or solids to sink or roll along the filter element 3, which are caught, collected or concentrated in a central area of ​​the filter element in the form of a collecting container, a capsule or sleeve.

[0067] The filter element 3 itself exhibits a rigidity that largely resists tensile, shear, bending, and / or torsional forces. This is important so that the filter element 3 can maintain a consistently conical or at least concave shape, which resists the helical, circular, or circular movement of the fluid containing the solids within the filter element 3.

[0068] In the present case, the filter element 3 is provided with frame elements that run through the filter element 3 in the form of ribs or gills. The filter element 3 has a mesh- or pore-shaped filter structure 5 (not shown) between the rib- or gill-shaped frame elements, through which the fluid can escape from the mesh- or pore-shaped filter element 3, while the solids remain within the filter element 3. Figure 2 shows the filter element 3 with housing 2 with a pre-chamber 11 and an insert / adapter 15 in a two-part embodiment in a vertical cross-section. A fluid containing solids flows (indicated by the upper vertical arrow) into a pre-chamber 11, in which an insert / adapter 15 is arranged. The insert / adapter 15 is spindle-shaped in the present case, so that the fluid flowing in with the solids already experiences a circular rotation within the pre-chamber 11.The pre-chamber 11 is connected to the housing 2 via flange connections 9. The fluid containing the solids flows from the pre-chamber 11 into the filter element 3 via an inlet opening 4. Due to the induced circular flow, the solids of the fluid in the area of ​​the filter element 3 are pressed laterally against the filter structure 5, which in this case is surrounded by gill-shaped or arc-shaped frame elements, and move in a rolling or sinking motion towards the bottom of the central area of ​​the filter element 3. At the bottom of the central area of ​​the filter element 3, one can see a collecting container, a capsule, or a sleeve into which solids have moved after their rolling or sinking movement along the filter structure 5 and are collected or concentrated there. The solids can also be sucked out of the collecting container, capsule, or sleeve via a valve or removed as retentate or concentrate via an outlet 14 of the bionic device 1.In parallel and / or simultaneously, the filtered fluid that has escaped laterally from the filter structure 5 can be returned to the fluid or (waste) water circuit via a filtrate outlet 13.

[0069] Figure 3 shows the filter element 3 with housing 2, comprising a pre-chamber 11 and an insert / adapter 15 in a two-part embodiment, in a vertical cross-section. A fluid containing solids flows (indicated by the upper vertical arrow) into a pre-chamber 11, in which an insert / adapter 15 is arranged. The insert / adapter 15 is spindle-shaped in this case, so that the fluid flowing in with the solids already undergoes a circular rotation within the pre-chamber 11. The pre-chamber 11 is connected to the housing 2 via flange connections 9. The fluid containing the solids flows from the pre-chamber 11 into the filter element 3 via an inlet opening 4.Due to the induced circular flow, the solids of the fluid in the area of ​​the filter element 3 are pressed laterally against the filter structure 5, which in this case is surrounded by frame elements in a gill-like or arched manner, and move in a rolling or sinking motion towards the bottom of the central area of ​​the filter element 3. At the bottom of the central area of ​​the filter element 3, one can see a collecting container, a capsule, or a sleeve in which solids are collected or concentrated. The solids that have reached the collecting container, the capsule, or the sleeve can be removed as retentate or concentrate via an outlet 14 of the bionic device 1. In parallel and / or simultaneously, the filtered fluid that has escaped laterally from the filter structure 5 can be returned to the fluid or (waste) water circuit via a filtrate outlet 13.

[0070] Figure 4 reveals a vertical cross-section of the pre-chamber 11 with a spindle-shaped insert / adapter 15. Within the outwardly conically widening pre-chamber 11, there is a spindle-shaped insert / adapter 15 which sets a fluid containing solids into a circular preferential movement in the direction of flow. As soon as the fluid containing the solids exits the central region of the flange, the fluid containing the solids, which has been set into a preferential movement by the spindle-shaped insert / adapter 15, can flow into a downstream filter element 3 (not shown). Due to the circularly induced flow in the region of the filter element 3, the solids are separated from the fluid at the filter structure 5 (not shown). The fluid exits laterally through the mesh-like or pore-like filter structure 5 and the solids sink or roll downwards along the filter structure 5.

[0071] Figure 5 shows a plan view of a helical prechamber 11 having a circular flange with bores. Analogous to the explanations for Figure 3, a fluid containing solids is set into a circular preferential movement in the direction of flow by the helical design of the prechamber 11. The fluid containing the solids exits as flatly as possible and directly onto the filter structure 5 (not shown) at the edge of the filter element 3 (not shown) through an opening in the helical prechamber 11. The fluid containing the solids can then flow into the filter element 3 (not shown) following downstream in the direction of flow.Due to the circularly induced flow in the area of ​​the filter element 3 (not shown), the solids are separated from the fluid at the filter structure 5 (not shown) by the fluid exiting laterally through the mesh-like or pore-like filter structure 5 (not shown) and the solids sinking or rolling downwards along the filter structure 5 (not shown).

[0072] List of reference symbols:

[0073] 1 bionic device

[0074] 2 Housing 3 Filter element

[0075] 4 Entrance opening

[0076] 5 Filter structure

[0077] 6 opening angles

[0078] 7 Container 8 Control mechanism

[0079] 9 flange connections

[0080] 10 siphon

[0081] 11 Antechamber

[0082] 12 Venting 13 Filtrate drain

[0083] 14 Retentate outlet (or concentrate outlet)

[0084] 15 insert / adapter

Claims

Patent claims 1. A bionic device (1) for separating microplastics from a fluid, wherein the device (1) consists of at least one housing (2) and at least one filter element (3) or at least one self-supporting filter element (3) which is gill-shaped and the fluid enters at one end via an inlet opening (4) into the housing (2) and the filter element (3) or the self-supporting filter element (3), and at the other end, the separated microplastics accumulate as retentate within the filter element (3) through a circular flow and can be drained or sucked off centrally in the region of the filter element (3) via a retentate outlet (14) and can be collected and removed in a container (7), wherein the housing (2) and the filter element (3) or the self-supporting filter element (3) have an opening angle (6) to the inlet opening (4) of α « 90° to generate the circular flow and are at least partially conical in design,wherein the filter element (3) at least partially has a mesh- or pore-shaped filter structure (5) and the fluid exits laterally through the mesh- or pore-shaped filter structure (5) of the filter element (3) and the filtrate outlet (13), characterized in that an analogue or digital control mechanism (8) interrupts the retentate outlet (14) to the collection and removal container (7) and ensures the drainage or suction of the microplastics periodically or continuously.

2. Device according to claim 1, characterized in that the inlet opening (4) comprises a pre-chamber (11) and / or an adapter (15) which is at least partially spindle-shaped or helical.

3. Device according to claim 1 or 2, characterized in that the inlet opening (4) is enclosed by a pre-chamber (11).

4. Device according to one of claims 1 to 3, characterized in that the filter element (3) has tensile, shear, bending and torsional rigidity.

5. Device according to one of claims 1 to 4, characterized in that the filter element (3) with the mesh- or pore-shaped filter structure (5) can be individually removed and / or washed from the bionic device (1).

6. Device according to one of claims 1 to 5, characterized in that the mesh- or pore-shaped filter structure (5) of the filter element (3) has openings of 20 pm to 500 pm, advantageously 50 pm to 100 pm.

7. Device according to one of claims 1 to 6, characterized in that the filter element (3) with the filter structure (5) consists of stainless steel and / or comprises a plastic fabric, wherein the filter element (3) and the filter structure (5) consist of the same or different materials.

8. Device according to one of claims 1 to 7, characterized in that the retentate can be collected in a container (7) and removed from the container (7).

9. Device according to one of claims 1 to 8, characterized in that the control mechanism (8) regulates a discharge of the microplastics from the area of ​​the filter element (3) or a backflow, in particular for cleaning the filter element (3).

10. Device according to one of claims 2 to 9, characterized in that the pre-chamber (11) is fastened to the housing (2) and / or to the filter element (3) by means of flange connections (9).

11. Device according to one of claims 1 to 10, characterized in that the bionic device (1) has a vent (12) and / or a siphon (10).

12. A method for separating microplastics from a fluid by means of a bionic device (1) consisting of at least one housing (2) and at least one filter element (3) or at least one self-supporting filter element (3) which is gill-shaped, wherein the fluid enters the housing (2) and the filter element (3) or the self-supporting filter element (3) at one end via an inlet opening (4) and at the other end the microplastics accumulate as retentate through a circular flow within the filter element (3) and can be drained or sucked off centrally in the region of the filter element (3) via a retentate outlet (14) and can be collected and removed in a container (7), wherein the housing (2) and the filter element (3) or the self-supporting filter element (3) have an opening angle (6) to the inlet opening (4) of α « 90° to generate the circular flow and are at least partially conical in design,wherein the filter element (3) at least partially has a mesh- or pore-shaped filter structure (5) and the fluid exits laterally through the mesh- or pore-shaped filter structure (5) of the filter element, characterized in that an analogue or digital control mechanism (8) interrupts the retentate flow (14) to the collecting container (7) and the removal or suction of the microplastics is ensured periodically or continuously.

13. The method according to claim 12, characterized in that the flow of the fluid with the microplastics is rotating and / or helical along the filter structure (5) within the filter element (3).

14. Method according to claim 12 or 13, characterized in that the filter element (3) is cleaned by an analogue or digital control mechanism.

15. Use of a bionic device (1) according to one of claims 1 to 11 in water remediation, wastewater and food processing, in particular for removing microplastics from the wastewater of dishwashers or washing machines.

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