A fluid filtration assembly, system, and method

Abstract

The application discloses a kind of fluid filtering assembly, system and method, including flexible filter membrane;With the rigid flow guide surface of the flexible filter membrane opposite arrangement, the rigid flow guide surface and flexible filter membrane between forming fluid flow channel;It further includes the flexible support layer located in the flexible filter membrane back to the rigid flow guide surface side, wherein, the flexible filter membrane under operating pressure produces elastic concave-convex deformation, and interact with the fluid flowing through fluid flow channel to produce turbulent flow.The beneficial effects of the present application are that the rigid flow guide surface and the flexible filter membrane form a fluid flow channel, the flexible filter membrane produces elastic concave-convex deformation under pressure, interacts with the fluid flowing through the fluid flow channel to produce turbulent flow, replaces the traditional flow guide net, can produce sufficient turbulent flow under medium-high pressure to reduce membrane contamination, also reduces the residue of concentrated solution, while avoiding the problem of flow guide net and membrane contact friction damage.

Description

Technical Field

[0001] This invention relates to the field of fluid separation technology, and in particular to a fluid filtration component, system and method. Background Technology

[0002] Radial flow filtration systems, especially in the biopharmaceutical field for filtering solutions rich in macromolecules such as proteins, generally face the problem of membrane fouling. Under pressure, molecules larger than the membrane pore size (such as proteins) in the solution will form a concentration polarization layer on the membrane surface, or even block the membrane pores, resulting in a sharp drop in filtration efficiency, an increase in transmembrane pressure, and a shortened membrane lifetime.

[0003] In existing technologies, a common approach to address this problem is to attach a flow-guiding mesh to the surface of the filter membrane. This mesh can artificially create turbulence, impacting the membrane surface and carrying away accumulated macromolecules, thereby reducing concentration polarization. However, this method has significant drawbacks: First, to prevent the rigid flow guide net from wearing down or puncturing the fragile filter membrane under the impact of fluid, the flow guide net cannot directly contact the membrane and must maintain a certain distance, which weakens the direct scouring effect of turbulence. Secondly, the guide net itself has a complex structure and a large thickness. Its dense mesh will retain a large amount of concentrate, resulting in a reduced product recovery rate. For high-value materials (such as exosome concentrate), this is an unacceptable loss.

[0004] Therefore, there is an urgent need in the field for a filter that can efficiently generate turbulence, prevent membrane clogging, and minimize concentrate residue. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to both efficiently generate turbulence to prevent membrane fouling and minimize concentrate residue.

[0006] The above-mentioned technical problems are solved by the following technical solution: The present invention proposes a fluid filtration assembly, which includes a flexible filter membrane; A rigid flow guide surface is disposed opposite to the flexible filter membrane, and a fluid flow channel is formed between the rigid flow guide surface and the flexible filter membrane; It also includes a flexible support layer located on the side of the flexible filter membrane facing away from the rigid flow guide surface. The flexible filter membrane undergoes elastic deformation under operating pressure, which interacts with the fluid flowing through the fluid channel to generate turbulence.

[0007] The beneficial effects of this invention are as follows: a fluid flow channel is formed between the rigid guide surface and the flexible filter membrane. The flexible filter membrane undergoes elastic deformation under pressure, and interacts with the fluid flowing through the fluid flow channel to generate turbulence. This replaces the traditional guide net, which can generate sufficient turbulence under medium and high pressure to reduce membrane fouling and reduce concentrate residue, while avoiding the problem of friction damage between the guide net and the membrane.

[0008] This invention proposes a fluid filtration system, comprising: a fluid inlet and an outlet, which are connected to the fluid flow channel; A pressure drive unit is used to provide pressure to the fluid inlet, causing fluid to pass through the fluid channel, the gap of the fluid channel being configured to generate turbulence under operating pressure; The rigid guide surface is configured to be in a position that facilitates the drainage of the concentrate after filtration, and the surface of the rigid guide surface is smooth and non-deformable.

[0009] In a preferred embodiment of the fluid filtration system of the present invention: the flexible filter membrane is a polymer filter material with an elastic modulus of 1.0~2.0 GPa.

[0010] In a preferred embodiment of the fluid filtration system of the present invention: the surface roughness Ra of the rigid guide surface is ≤0.1μm.

[0011] In a preferred embodiment of the fluid filtration system of the present invention: the volume porosity of the flexible support layer is ≥85%, the pore size distribution is 10~50μm, and the compression modulus is 0.5~1.5MPa.

[0012] In a preferred embodiment of the fluid filtration system of the present invention, the gap size of the fluid flow channel is configured such that the Reynolds number is greater than 2000 at the operating pressure of the pressure drive unit.

[0013] In a preferred embodiment of the fluid filtration system of the present invention, the operating pressure provided by the pressure drive unit is 0.1~0.3MPa.

[0014] In a preferred embodiment of the fluid filtration system of the present invention: the flexible filter membrane deforms under operating pressure with a wavelength of 0.5 to 2 mm and an amplitude of 10 to 50 μm.

[0015] In a preferred embodiment of the fluid filtration system of the present invention: after filtration, the residual rate of the concentrate on the rigid guide surface is less than 0.5%, and the residual volume is less than 0.1 mL / 100 cm² flow channel area.

[0016] This invention proposes a fluid filtration method, comprising the following steps: S1: Introduce the fluid to be filtered into the fluid flow channel; S2: The pressure driving unit applies an operating pressure of 0.1~0.3MPa, causing the flexible filter membrane to deform towards the flexible support layer, forming an uneven structure; S3: Turbulence is generated within the fluid flow channel through the synergistic effect of the concave and convex structure and the narrow fluid flow channel; S4: Collect the filtrate that has passed through the flexible filter membrane and the flexible support layer; S5: After filtration, the pressure is released, and gravity is used to allow the concentrate to flow out completely along the rigid guide surface and be collected.

[0017] The beneficial effects of this invention are as follows: the design of a flexible filter membrane, a rigid flow guide surface, and a flexible support layer enables high-throughput stable filtration of fluid under pressure of 0.1~10MPa, with a concentrate residue rate of less than 0.5%. At the same time, the structure is simplified, avoiding the material retention and membrane damage problems caused by traditional flow guide nets. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Wherein: Figure 1 A schematic diagram of a flow filter structure and its working principle under operating pressure is shown. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0021] Reference Figure 1 This embodiment provides a fluid filtration structure, including a flexible filter membrane 11, which is the core filtration element. Unlike traditional filtration structures, the flexible filter membrane 11 does not rely on an external flow guide to generate turbulence, but instead utilizes its own elastic properties to achieve this function. A rigid flow guide surface 12 is disposed opposite to the flexible filter membrane 11. A fluid flow channel is formed between the rigid flow guide surface 12 and the flexible filter membrane 11. Its main function is to provide a directional flow channel for the fluid and to cooperate with the flexible filter membrane 11 to form a pressure difference. It also includes a flexible support layer 13 located on the side of the flexible filter membrane 11 facing away from the rigid guide surface 12. That is, the flexible support layer 13 is the side that does not contact the fluid. It can provide necessary support for the flexible filter membrane 11 and allow the filtrate that has passed through the flexible filter membrane 11 to be discharged smoothly. This layer has appropriate mechanical strength and flexibility, which can ensure the structural integrity of the flexible filter membrane 11 without hindering its deformation ability. The flexible filter membrane 11 undergoes elastic deformation under operating pressure, which interacts with the fluid flowing through the fluid channel to generate turbulence. The interaction between the elastic deformation and the fluid flowing through the channel generates local turbulence and vortices. This self-generated turbulence effectively destroys the concentration polarization layer on the surface of the flexible filter membrane 11, reduces membrane fouling, and avoids the dead zone and high residue problems caused by traditional rigid flow guide nets.

[0022] Reference Figure 1 This embodiment provides a fluid filtration system, including a fluid filtration assembly. The core of the system is the fluid filtration assembly, which, together with the fluid passage and pressure, forms a high-efficiency filtration unit. The fluid inlet and outlet are connected to the fluid flow channel to form a complete fluid passage. The fluid inlet receives the solution to be treated, and after filtration, the filtrate is discharged from the outlet, while the retained concentrate forms a concentrated liquid within the system. The pressure drive unit is used to provide pressure to the fluid inlet, so that the fluid passes through the fluid channel. The gap of the fluid channel is configured to generate turbulence under the operating pressure. The pressure drive unit consists of a pump or a pressure tank. In this embodiment, a pump is used to provide a stable operating pressure of 0.1~10MPa to the fluid inlet. The space of the channel is designed and its width is configured so that the fluid can naturally form a turbulent state under the action of the operating pressure. The rigid guide surface 12 is configured to be in a position that facilitates the drainage of the concentrate after filtration. The rigid guide surface 12 has a smooth surface and is not deformable. In this embodiment, the filter assembly can be adjusted to an inclined or vertical state after filtration to form a configuration that facilitates the complete drainage of the concentrate. The smooth and non-deformable rigid guide surface 12 ensures that almost no liquid can adhere to or remain on the surface, reducing the residual loss of high-value materials. In this system, radial flow and tangential flow are essentially the same filtration method, and radial flow and tangential flow are equally applicable.

[0023] Preferably, the flexible filter membrane 11 is a polymer filter material with an elastic modulus of 1.0~2.0 GPa. The flexible filter membrane 11 has an elastic modulus of 1.0~2.0 GPa, which ensures that the filter membrane maintains its structural integrity under an operating pressure of 0.1~10 MPa and will not undergo permanent deformation or damage. At the same time, it is low enough to allow the filter membrane to produce micron-level controllable elastic concave and convex deformation under the action of pressure gradient, so as to interact with the fluid flowing through the flow channel, induce effective turbulence, and destroy the concentration polarization layer on the membrane surface. In this embodiment, the flexible filter membrane 11 is specifically made of polyvinylidene fluoride (PVDF) and polyethersulfone (PES), and its thickness is 100~200 μm.

[0024] Preferably, the surface roughness Ra of the rigid guide surface 12 is ≤0.1μm. This value represents a highly smooth surface, which reduces the fluid flow resistance and allows the fluid to flow closely along the rigid guide surface 12, preventing particles from anchoring and depositing on the surface and significantly reducing the risk of contamination. In the evacuation stage after filtration, the smooth surface tension effect makes the residual liquid film slide off very easily, minimizing dead zone residue.

[0025] Preferably, the flexible support layer 13 has a volumetric porosity ≥85%, a pore size distribution of 10~50 μm, and a compressive modulus of 0.5~1.5 MPa. In this embodiment, the flexible support layer 13 is made of a porous material. A volumetric porosity ≥85% means that more than 85% of the space inside the support layer is an interconnected pore network. This pore structure reduces the resistance to filtrate passage, ensuring that the filtration flux is not limited by the support structure. Even under a high pressure of 10 MPa, the filtrate can be quickly discharged through the flexible support layer 13, avoiding accumulation on the back side of the membrane and the formation of additional resistance. The pore size distribution is 10~50 μm. Within the range of 0 to 50 μm, it can uniformly distribute pressure and provide a delicate distribution of support points, preventing the flexible filter membrane 11 from undergoing excessive local deformation or damage under high pressure. The compression modulus of 0.5 to 1.5 MPa is an optimized parameter, which has moderate compressibility under pressure and is lower than the elastic modulus of the flexible filter membrane 11 (1.0 to 2.0 GPa). Under operating pressure, the flexible support layer 13 can generate slight elastic compression, which, together with the filter membrane, achieves overall coordinated deformation and enhances the turbulence effect. The above three parameters together constitute a support system that is both air-permeable and liquid-permeable and has a precise mechanical response.

[0026] Furthermore, the gap size of the fluid channel is configured such that the Reynolds number is greater than 2000 under the operating pressure of the pressure-driven unit, achieving the transition from laminar to turbulent flow. The Reynolds number is a key parameter for determining the flow regime; when Re > 2000, the fluid begins to enter a transitional flow state and develops into fully turbulent flow at higher velocities. The channel gap height, along with the fluid velocity, viscosity, and density, jointly determines the Reynolds number. By precisely controlling this gap size, the system can generate vortices and disturbances on the membrane surface using the fluid's own dynamic characteristics without relying on traditional guide nets. This utilizes fluid dynamics principles, avoiding the dead zones and high residue problems caused by guide nets in traditional filtration systems, while ensuring highly efficient anti-fouling effects. Reynolds number formula: Re: Reynolds number, representing the ratio of inertial forces to viscous forces in fluid flow. When Re is very small (e.g., <2000): viscous forces dominate, and the flow is a smooth, stratified laminar flow. When Re is very large (e.g., >4000): inertial forces dominate, and the flow is turbulent, filled with vortices. Between 2000 and 4000, it is usually referred to as a transitional flow; The density of a fluid, measured in kilograms per cubic meter (kg / m³), is the mass of a unit volume of fluid. It reflects the fluid's "inertia"; the greater the density, the greater the inertia. The characteristic velocity of a fluid, measured in meters per second (m / s), is the representative speed of fluid flow. It can refer to different things in different scenarios. For example, it can be the cross-sectional average velocity in a pipe, or the incoming flow velocity when flowing around an object. Characteristic length, unit: meter (m), is the representative geometric dimension of the problem under study. Its specific meaning varies depending on the context, for example: When flow occurs inside a circular pipe, d usually refers to the inner diameter of the pipe. When fluid flows around a sphere, d usually refers to the diameter of the sphere. When a fluid flows along a flat plate, d may refer to the length of the plate along the flow direction; Dynamic viscosity (or dynamic viscosity coefficient) of a fluid, measured in Pascal-seconds (Pa·s) or N·s / m², but more commonly in centipoise (cP), where 1 cP = 0.001 Pa·s. It is a physical quantity that measures a fluid's resistance to deformation (i.e., viscosity). The larger the fluid, the more viscous it is, and the more difficult it is to flow (such as honey); The smaller the value, the "less" the fluid, and the easier it is to flow (such as water and air).

[0027] Preferably, the operating pressure provided by the pressure drive unit is 0.1~0.3MPa. In this embodiment, the operating pressure provided by the pressure drive unit is precisely limited to a low pressure range of 0.1~0.3MPa (1~3 bar). This specific pressure range is a preferred value, representing a balance between filtration performance and structural integrity.

[0028] Furthermore, the flexible filter membrane 11 deforms under operating pressure with a wavelength of 0.5–2 mm and an amplitude of 10–50 μm. In this embodiment, when the fluid flows through the elastically deformed membrane, alternating micro-vortices are formed behind the wave crests, effectively disrupting the concentration polarization layer on the membrane surface. A wavelength less than 0.5 mm will cause turbulent energy dissipation to be too rapid; a wavelength greater than 2 mm will form an uneven flow field, creating a filtration dead zone. The design of an amplitude of 10–50 μm ensures that the deformation will not contact the rigid guide surface 12 and cause damage; at the same time, it is precisely within the fluid boundary layer thickness range (typically 5–100 μm), maximizing the disturbance effect. Relationship between filter membrane deformation and turbulence intensity: Deformed wavelength Approximately 0.5~2 mm Deformation amplitude A: 10~50 μm (micrometer-level unevenness) The relationship between turbulence intensity I_t and amplitude is approximately: This indicates a direct proportional relationship, where V is the flow velocity and d is the channel clearance.

[0029] Furthermore, after filtration, the residue rate of the concentrate on the rigid guide surface 12 is less than 0.5%, and the residue volume is less than 0.1 mL / 100 cm² flow channel area, representing the industry's low residue level and possessing significant technical value.

[0030] refer to Figure 1 As an optional embodiment, a fluid filtration method, characterized in that it is applied to a fluid filtration system, includes the following steps: S1: Introduce the fluid to be filtered into the fluid flow channel; S2: The pressure driving unit applies an operating pressure of 0.1~0.3MPa, causing the flexible filter membrane 11 to deform towards the flexible support layer 13, forming a concave-convex structure. The pressure driving unit precisely applies an operating pressure of 0.1~0.3MPa (typical value 0.2MPa). Within this specific pressure range, the flexible filter membrane 11, which has an elastic modulus of 1.0~2.0GPa, undergoes controllable elastic deformation towards the flexible support layer 13, forming a regular microwave textured structure with a wavelength of 0.5~2mm and an amplitude of 10~50μm. Pressure control ensures stable and repeatable deformation and avoids membrane material fatigue. S3: Through the synergistic effect of the concave-convex structure and the narrow fluid flow channel, turbulence is formed in the fluid flow channel. The concave-convex structure and the fluid flow channel (0.1~0.5mm) produce a synergistic effect of hydrodynamics. When the fluid flows through the surface of the concave-convex structure, the local Reynolds number exceeds 2000 and enters the turbulent state. The turbulence effectively destroys the concentration polarization layer on the membrane surface. Experiments have shown that it can reduce the flux decay rate of protein solution by more than 70%, and no traditional flow guiding mesh structure is required. S4: Collect the filtrate that has passed through the flexible filter membrane 11 and the flexible support layer 13. The filtrate that has passed through the flexible filter membrane 11 quickly passes through the flexible support layer 13, which has a volume porosity of ≥85% and a pore size of 10~50μm. This highly permeable structure ensures that the filtrate resistance is minimized. The filtrate enters the receiving container through a dedicated collection channel. The filtration accuracy is controlled by the pore size specification (0.01~1.0μm) of the flexible filter membrane 11. It is suitable for various cell suspensions, such as protein solutions. S5: After filtration, the pressure is released, and gravity is used to allow the concentrate to flow out completely along the rigid guide surface 12 and be collected. After filtration, the flexible filter membrane 11 returns to a flat state, and the filter assembly is tilted. Gravity is used to allow the concentrate to slide completely down the smooth rigid guide surface (Ra≤0.1μm). This design reduces the concentrate residue rate to below 0.5% and the residue volume to less than 0.1mL / 100cm². The recovery rate of high-value biological products (such as exosomes and monoclonal antibodies) exceeds 95%, which is superior to traditional filtration methods.

[0031] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A fluid filtration assembly, characterized in that: include, Flexible filter membrane (11); A rigid flow guide surface (12) is disposed opposite to the flexible filter membrane (11), and a fluid flow channel is formed between the rigid flow guide surface (12) and the flexible filter membrane (11); It also includes a flexible support layer (13) located on the side of the flexible filter membrane (11) facing away from the rigid flow guide surface (12). The flexible filter membrane (11) undergoes elastic deformation under operating pressure, which interacts with the fluid flowing through the fluid channel to generate turbulence.

2. A fluid filtration system, characterized in that, Including the fluid filtration assembly as described in claim 1, further comprising: The fluid inlet and outlet are in communication with the fluid flow channel; A pressure drive unit is used to provide pressure to the fluid inlet, causing fluid to pass through the fluid channel, the gap of the fluid channel being configured to generate turbulence under operating pressure; The rigid guide surface (12) is configured to be in a position that facilitates the drainage of the concentrate after filtration. The rigid guide surface (12) has a smooth surface and is not deformable.

3. The fluid filtration system according to claim 2, characterized in that: The flexible filter membrane (11) is a polymer filter material with an elastic modulus of 1.0~2.0 GPa.

4. The fluid filtration system according to claim 3, characterized in that: The surface roughness Ra of the rigid guide surface (12) is ≤0.1μm.

5. The fluid filtration system according to claim 4, characterized in that: The flexible support layer (13) has a volume porosity ≥85%, a pore size distribution of 10~50μm, and a compressive modulus of 0.5~1.5MPa.

6. The fluid filtration system according to claim 5, characterized in that: The clearance size of the fluid flow channel is configured such that the Reynolds number is greater than 2000 at the operating pressure of the pressure drive unit.

7. The fluid filtration system according to claim 6, characterized in that: The pressure drive unit provides an operating pressure of 0.1~0.3MPa.

8. The fluid filtration system according to claim 2 or 3, characterized in that: The flexible filter membrane (11) deforms under operating pressure with a wavelength of 0.5 to 2 mm and an amplitude of 10 to 50 μm.

9. The fluid filtration system according to claim 2, characterized in that: After filtration, the residual rate of the concentrate on the rigid guide surface (12) is less than 0.5%, and the residual volume is less than 0.1 mL / 100 cm² flow channel area.

10. A fluid filtration method, characterized in that, The fluid filtration system described in any one of claims 2 to 9 comprises the following steps: S1: Introduce the fluid to be filtered into the fluid flow channel; S2: The pressure driving unit applies an operating pressure of 0.1~0.3MPa, causing the flexible filter membrane (11) to deform towards the flexible support layer (13) to form a concave-convex structure; S3: Turbulence is generated within the fluid flow channel through the synergistic effect of the concave and convex structure and the narrow fluid flow channel; S4: Collect the filtrate that has passed through the flexible filter membrane and the flexible support layer; S5: After filtration, the pressure is released, and gravity is used to make the concentrate flow out completely along the rigid guide surface (12) and collect it.

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