Abstract
The present innovation relates to novel and versatile nanomembrane to be used in filtration system and manufacturing method to produce it. The filter membrane may result in significant reduction in energy demand and higher capture efficiency. The filter membrane may have one or multiple nanomembrane part of overall filtration system. The manufacturing uses a combined electric and air flow field to produce the nanomembrane, which may be included as in-line module in standard filter manufacturing process. The method of nanomembrane production is optimized by machine learning-based optimization protocol based on physics-based modeling via feedback control.
Claims
1. A filtration system for filtration of fluid, both air and/or liquid, the filter system comprising: single or plurality of nanomembranes being included in the filter design, where the nanomembranes being sandwiched between traditional filtration components and/or nanomembrane coating on traditional filter components, wherein the resultant filtration system can be cut, formed and shaped into a variety of shapes and/or the filter can have 3D hierarchical design to start with and the nanomembrane can be added as an addendum.
2. The nanomembranes of claim 1, consists of nanofibers, which can be of any materials but primarily polymeric or polymer derived in nature, have diameter ≤ 100 nm and thickness of each nanomembrane may not exceed 500 nm.
3. The nanomembranes of claim 1, will result in higher capture efficiency, at least 20-50%, especially nanoparticles with diameter ≤ 400 nm.
4. The nanomembranes of claim 1, may allow higher volumetric porosity of the overall filter system resulting in significantly lower energy demand.
5. The nanomembrane of claim 1, may not require any further treatment to adhere to the filter system owing to its superior van der Waals force in its original polymeric form. However, a polymer derived material namely, copolymer, ceramic etc. may require further treatment.
6. A method of making nanomembrane-based filter of claim 1, wherein method comprises of producing stream of polymer jet resulting in polymer nanofibers of diameter ≤ 100 nm using a combined stretching force of high electric field (~1-5 kV/cm) and high velocity air flow field (subsonic and supersonic) getting collected on collector membrane, wherein single or plurality of polymer jet issuing methods comprising of cylindrical rotor submerged in polymer bath with or without exterior patterns and/or series of sharp objects (e.g.- needles) submerged in polymer bath and/or polymer jet issuing head with patterned opening or needles or oscillating stoppers capable of closing and opening slot issuing polymer jets against or in the direction of gravity utilizing polymer jet instabilities to drive attenuation polymer jets to diameter ≤ 100 nm.
7. The method of claim 6 gets enhanced by physics-based computer vision and AI/ML/edge computing methodology, whereby process specific output is optimized based on input and environmental parameters.
Description
BRIEF DESCRIPTION OF THE DRAWING
[0042] FIG. 1 illustrates two different configurations of the filter assembly.
[0043] FIG. 2 illustrates schematics of comparison of filtration system between standard filter and the present filter. It also illustrates the structure-property-process map of present filtration system.
[0044] FIG. 3 illustrates an example of nanomembrane production system, where the polymer jet issues from a cylinder submerged in polymer solution bath. Two different examples of cylinder exterior are shown. The underlying mechanism of jet formation, capillary instability is shown.
[0045] FIG. 4 illustrates an example of nanomembrane production system, where the polymer jet issues from needles submerged in polymer bath is shown.
[0046] FIG. 5 illustrates an example of nanomembrane production system, where the polymer jet issues from a polymer jet issuing head is shown. Different configurations of head are shown in the form of patterned head and/or needles and/or oscillating stoppers capable of closing and opening slot. The polymer jets are issued against gravity.
[0047] FIG. 6 illustrates an example of nanomembrane production system, where the polymer jet issues from a polymer jet issuing head is shown. Different configurations of head are shown in the form of patterned head and/or needles and/or oscillating stoppers capable of closing and opening slot. The polymer jets are issued towards gravity.
[0048] FIG. 7 illustrates the flow process to optimize the physics-based machine leaning process that optimize the nanomembrane manufacturing process.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] The present invention relates to nanomembrane enhanced filter and the methods of producing them. More specifically FIG. 1 shows two examples of filter configurations with the nanomembranes. 100a and 100b shows two possible examples of embedding one or multiple layers of nanomembrane. 100a shows the nanomembrane being sandwiched between multiple layers of filter membranes. The overall filter membrane is a n layer membrane, where n≥ 3. 101 is the first traditional filtration layer in a filter, 102 is the nanomembrane layer, which is the m-th layer, 103 is n-th traditional filtration layer in the overall filtration, where 1<m<n. 100 b shows the configuration, where the nanomembrane is applied as a coating to the filtration membrane, where 104 is first layer in a filter, 105 is m-th nanomembrane layer and m≥ 3. In the examples, only 1 active layer is shown. However, in reality, there can be multiple layers of nanomembrane that are part of the overall filtration assembly/system. These filtration systems may be used in the form of sheets. They may also be cut, formed and shaped into other shapes. The nanomembrane layer may be applied on other shapes (e.g.- tubes). The nanomembrane layer has very high van der Waals force, which allows it to stick with any surface. This allows that the nanomembrane layer may not require any further treatment (e.g.- thermal and/or chemical) for attachment and can be used as an inline process. The nanomembrane layer may not exceed thickness of 500 nm and the fiber diameter may not exceed 100 nm. Plurality of polymers can be used to create the nanomembrane layers, which are optimized by polymer properties, namely- viscoelasticity, glass transition temperature (T.sub.g), solubility etc. Examples of some polymers are, but not limited to, PVA, nylon, PET, PVDF etc. In some cases polymer derived secondary materials may also be used, where polymers act as carrier materials to create secondary material following chemical and/or thermal treatment. Some examples, but not limited to are creation of ceramic nanofibers, where precursor materials (such as- alkoxide, orthosilicates etc.) may not have enough viscoelasticity but can be mixed with polymeric materials to created composite nanofibers, which on further treatment will result in ceramic nanomembrane.
[0050] FIG. 2 shows a schematic of comparison of traditional vs present solution. Here 201 is the unfiltered fluid, 202 is traditional filter media, 203 is nanomembrane coated on traditional filter and 204 is filtered fluid. As shown in FIG. 2, the present nanomembrane layer doesn’t create any additional backpressure but increases capture efficiency. This may translate into more open base filter resulting in higher volumetric porosity at a higher capture rate of small nanoparticles (diameter ≤ 400 nm) and thereby increased filtration efficiency both from the viewpoint of capture rate and energy demand. FIG. 3 explains the overall structure-property-effect relationship. The physics behind this can be explained as the following. Theoretically, the second law of Newton for an individual nanoparticle/nanoparticle cluster interacting with individual fiber of a filter reads as
[00001]
where A>0 is the Hamaker constant, and the force is attractive, v.sub.p is the nanoparticle velocity, m.sub.p is its mass, m.sub.ℓ is the mass of liquid displaced by the nanoparticle, and the last term of the right-hand side is the Stokes drag force, with .Math. being the liquid viscosity. Note also, that in Eq. (1) cosθ = x.sub.p / (x.sub.P.sup.2 + y.sub.p.sup.2).sup.½ and sinθ = y.sub.p / (x.sub.p.sup.2 + y.sub.p.sup.2).sup.½.
[0051] The momentum balance equation (1) is supplemented by the kinematic equation
[00002]
for the position vector of the virus/virus cluster R.sub.p = ix.sub.p + jy.sub.p. Numerical solution will show that nanoparticle suspension ( ≤ 400 nm) interacts with nanofiber diameter ≤ 100 nm, the capture efficiency increases drastically in comparison to larger fibers. For the sake of brevity, it can be summarized as the following. During filtration, fluid streamlines carrying nanoparticles get displaced by fibers in filter media, which is of the order of fiber diameter. Nanomembranes described here displaces streamlines minimally. Thereby enabling attractive van der Waals force (short range force) to capture particles. Additionally, the surface area to volume ratio of the present nanomembrane is very high. This increases the probability of interaction between particles and ultrafine nanofibers even in few monolayer thickness (~100-500 nm). This small thickness ensures the volumetric porosity of the ultrafine nanofiber coating remains high and thus the additional pressure drop is negligible.
[0052] In one embodiment, FIG. 3 specifically illustrates the manufacturing methodology of nanomembrane layer. 301 is polymer solution input, 302 is rotating cylinder, 302a and 302b are possible configurations of the rotating cylinders, 302c is the capillary instability that forms polymer jets and 302d is the polymer solution covering the rotating cylinder and 302e is the rotating cylinder. 303 is the high voltage (dc) electric field that is connected to the rotating cylinder. 304 is the compressed air source, which is connected to 305, air curtains and/ knives and/or nozzles. 305 is grounded and the electric field between 305 and 302 is ~ 1-5 kV/cm. 306 is the collector membrane. 302 is partially submerged in a polymer bath. As it comes up to open air, the free surface results in capillary instability. On application of high electric field, they form polymer jets, which gets attracted towards the grounded 305, which issues air jet at a very high velocity (subsonic and supersonic). This results in enormous stretching of the polymer jets and results in ultrafine nanofiber getting collected on 306 forming nanomembrane.
[0053] In another embodiment, FIG. 4 specifically illustrates an alternate manufacturing methodology of nanomembrane layer. 401 is polymer solution input, 402 is multiple needles creating sharp polymer finger like instabilities. 403 is the high voltage (dc) electric field that is connected to the needles. 404 is the compressed air source, which is connected to 405, air curtains and/ knives and/or nozzles. 405 is grounded and the electric field between 405 and 402 is ~ 1-5 kV/cm. 406 is the collector membrane. 402 is partially submerged in a polymer bath. As it comes up to open air, the free surface results in capillary instability. On application of high electric field, they form polymer jets, which gets attracted towards the grounded 405, which issues air jet at a very high velocity (subsonic and supersonic). This results in enormous stretching of the polymer jets and results in ultrafine nanofiber getting collected on 406 forming nanomembrane.
[0054] In another embodiment, FIG. 5 specifically illustrates an alternate manufacturing methodology of nanomembrane layer. 501 is polymer solution input and 502 is the polymer reservoir. 503 is the high voltage (dc) electric field that is connected to the rotating cylinder. 504 is the compressed air source, which is connected to 505, air curtains and/ knives and/or nozzles. 505 is grounded and the electric field between 505 and 502 is ~ 1-5 kV/cm. 506 is the collector membrane. 507 is the polymer jet head that can have variety of configurations including 507a and/or 507b and/or 507c. 507a shows the jet head with patterned opening issuing polymer jets, whereas 507b shows jet head with multiple needles issuing polymer jets and 507c shows slot opening with oscillating stoppers capable of closing and opening slot resulting in issuance of polymer jets. On application of high electric field, the polymer jets get attracted towards the grounded 505, which issues air jet at a very high velocity (subsonic and supersonic). This results in enormous stretching of the polymer jets and results in ultrafine nanofiber getting collected on 506 forming nanomembrane. The polymer jets are issued against the gravity.
[0055] In another embodiment, FIG. 6 specifically illustrates an alternate manufacturing methodology of nanomembrane layer. 601 is polymer solution input and 602 is the polymer reservoir. 603 is the high voltage (dc) electric field that is connected to the rotating cylinder. 604 is the compressed air source, which is connected to 605, air curtains and/ knives and/or nozzles. 605 is grounded and the electric field between 605 and 602 is ~ 1-5 kV/cm. 606 is the collector membrane. 607 is the polymer jet head that can have variety of configurations including 607a and/or 607b and/or 607c. 607a shows the jet head with patterned opening issuing polymer jets, whereas 607b shows jet head with multiple needles issuing polymer jets and 607c shows slot opening with oscillating stoppers capable of closing and opening slot resulting in issuance of polymer jets. On application of high electric field, the polymer jets get attracted towards the grounded 605, which issues air jet at a very high velocity (subsonic and supersonic). This results in enormous stretching of the polymer jets and results in ultrafine nanofiber getting collected on 606 forming nanomembrane. The polymer jets are issued towards the gravity.
[0056] The manufacturing systems described here may be used as stand-alone unit or may be using in conjunction with one another. This will allow further flexibility in design and operation to develop complicated filtration systems. The manufacturing process is optimized by physics driven machine learning process, whose process flow is shown in FIG. 7. Some of the key process variables for the manufacturing process are: polymer viscoelasticity, electric field, air velocity, initial polymer jet diameter, relative distances between air curtains/knives/curtains and the collector and polymer jet origination point, environmental conditions (e.g., temperature, humidity), polymer throughput and inline process specific variables. All of these are included in the manufacturing process. Using computer vision and AI/ML/Edge computing-based platforms the process parameters are optimized against output (fiber size in nanomembrane, filtration efficiency etc.). The process is designed to get better with time.
[0057] While different embodiments of the present filtration system are shown and described, it will be appreciated in the filtration industry skilled in the art that performs modifications may be made thereto without departing from the invention in its broader aspects as set forth in the following claims.
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