DESC:The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

FIELD OF INVENTION
[0001] The embodiments herein relate to coating of surfaces. More particularly relates to a method and an apparatus for coating a fabric with a solution to incorporate specific features to the fabric by cavitation. The present application is based on, and claims priority from an Indian Application Number 202041019629 filed on 8th May 2020 the disclosure of which is hereby incorporated by reference herein

BACKGROUND OF THE INVENTION
[0002] In general, with advancement in textile technology has resulted in improved fabrics and textiles. Antibacterial, antimicrobial or antiviral fabrics are widely used for production of outdoor clothes, under-wear, bed-linen, bandages, etc. However, the process of manufacturing may be time consuming and expensive. Further, in a pandemic situation like the one witnessed since the 2020 COVID-19 pandemic the demand for the improved fabrics and textiles to protect the users may be accompanied with a need to slow down the rate of transmission of virus to break the chain. One such possibility of slowing down the rate of transmission of the virus is by using self-disinfecting surfaces which can inactivate the virus on most surfaces which will eventually slow the transmission rate.
[0003] Some of the conventional coatings to incorporate self-disinfectant properties include nanoparticles coating which are coated by ultrasonic irradiation on the surface of various substrates including ceramics and polymers. Such deposition results in a highly homogenous surface coating and high adhesions. Micro jets and shock waves produced by the ultrasonic cavitation drive the nanoparticles in very high velocities towards a substrate and the velocities are high enough to adhere strongly either chemically or physically depending on the substrate and particles used. This similar process can be used for coating of the textiles like cotton, nylon, polyester etc. However the previous research or laboratory experiments suggest that it takes about one hour to coat 1 meter of a textile. This is a major drawback in commercial setup where the textile needs to be coated at higher speeds. Another drawback of the process is that the laboratory setups can only coat one textile after another and do not have the ability to coat different textiles at the same time. So the coating process might take days to weeks for completion before the textiles can be used for any commercial purposes. These delays also add a lot of cost to the overall finished product prepared using the coated textiles.
[0004] Thus, it is desired to address the above mentioned disadvantages or other shortcomings or at least provide a useful alternative.

OBJECT OF INVENTION
[0005] The principal object of the embodiments herein is to provide a method and an apparatus for coating a fabric with a solution to incorporate specific features to the fabric such as self- disinfecting features by cavitation process using multiple ultrasonic irradiation chambers through which the fabric is passed to achieve the coating. The apparatus and the method enable fast, efficient and economic coating mechanisms especially for bulk manufacturing within a short period of time.
[0006] Another object of the embodiments herein is to provide an environmentally friendly and power efficient method for coating the fabrics. The apparatus and method provide various mechanisms for collection of unwanted solutions from the fabric which is fed back to a reserve tank and reused for coating.
SUMMARY
[0007] Accordingly, the embodiments herein provide An apparatus for coating a fabric with a solution. The apparatus includes a first roller for loading the fabric to be coated and a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers for coating the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the apparatus includes a silicon roller for removing unwanted portions of the solution after the cavitation process and a drying chamber comprising a plurality of heat rollers for drying the fabric coated with the solution. The apparatus also includes a management controller for managing a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus; and a second roller for unloading the dried fabric coated with the solution.
[0008] In an embodiment, the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber is of 1.82m to 1.85m length, 33cm to 37 cm width, 21.5 cm height and 0.13 to 0.14 cubic meter volume.
[0009] In an embodiment, the first ultrasonic irradiation chamber comprises a first fixed ultrasonic transducer unit located at a bottom portion of the first ultrasonic irradiation chamber connected in parallel to a first adjustable ultrasonic transducer unit located at a top portion of the first ultrasonic irradiation chamber, and wherein the first fixed ultrasonic transducer unit and the first adjustable ultrasonic transducer unit are of 1.65-1.8m length, 14-18 cm width and 9.5 to 10cm height.
[0010] In an embodiment, each of the first fixed ultrasonic transducer unit and the first adjustable ultrasonic transducer unit comprises a plurality of miniature piezo-electric transducers provided at a center-to-center distance between the plurality of miniature piezo-electric transducers one of: 7 cm in a linear arrangement and 3.5 cm in a non-linear arrangement.
[0011] In an embodiment, the plurality of miniature piezo-electric transducers is embedded in a hollow box to provide maximum resonant frequencies of range of 20- 40 KHz for the hollow box and to provide uniform micro jets in the solution for uniform coating of the fabric passed through the first irradiation chamber.
[0012] In an embodiment, the second ultrasonic irradiation chamber comprises a second fixed ultrasonic transducer unit located at a bottom portion of the second ultrasonic irradiation chamber connected in parallel to a second adjustable ultrasonic transducer unit located at a top portion of the second ultrasonic irradiation chamber, and wherein the second fixed ultrasonic transducer unit and the second adjustable ultrasonic transducer unit are of 1.65-1.8m length, 14-18 cm width and 9.5 to 10cm height.
[0013] In an embodiment, each of the second fixed ultrasonic transducer unit and the second adjustable ultrasonic transducer unit comprises a plurality of miniature piezo-electric transducers provided a center-to-center distance between the plurality of miniature piezo-electric transducers one of: 7 cm in a linear arrangement and 3.5 cm in a non-linear arrangement.
[0014] In an embodiment, the plurality of miniature piezo-electric transducers is embedded in a hollow box to provide maximum resonant frequencies of range of 20- 40 KHz for the hollow box and to provide uniform micro jets in the solution for uniform coating of the fabric passed through the second ultrasonic irradiation chamber.
[0015] In an embodiment, the fabric of width in a range of 30 cm to 2 meters is coated by the apparatus.
[0016] In an embodiment, each of the first ultrasonic irradiation chambers of the plurality of first ultrasonic irradiation chambers are vertically stacked, and each of the second ultrasonic irradiation chambers of the plurality of second ultrasonic irradiation chambers are vertically stacked.
[0017] In an embodiment, each set of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber comprises a different solution for coating a different fabric.
[0018] In an embodiment, each of the first ultrasonic irradiation chambers of the plurality of first ultrasonic irradiation chambers and each of the second ultrasonic irradiation chambers of the plurality of second ultrasonic irradiation chambers are connected in series, and wherein each of the first ultrasonic irradiation chambers of the plurality of first ultrasonic irradiation chambers comprises the solution for coating the fabric to increase an exposure time of the fabric to the solution at high rolling speeds.
[0019] In an embodiment, the first adjustable ultrasonic transducer unit of the first ultrasonic irradiation chamber is attached to a first spring loaded mechanism and the second adjustable ultrasonic transducer unit of the second ultrasonic irradiation chamber is attached to a second spring loaded mechanism.
[0020] In an embodiment, the first spring loaded mechanism and the second spring loaded mechanism is used for loading and locking the fabric inside the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber respectively; and for maintaining a distance between the fabric and the parallel ultrasonic transducers of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber.
[0021] In an embodiment, the distance between the fabric and the parallel ultrasonic transducers of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber is maintained at a range of 10mm - 30 mm depending on the type of the fabric and the solution.
[0022] In an embodiment, the management controller is configured to receive a measurement from a level switch at the first ultrasonic irradiation chamber indicating a level of the solution to be coated on the fabric and determine that the solution in the first ultrasonic irradiation chamber is below a predefined level. Further, the management controller is configured to automatically refill the solution in the first ultrasonic irradiation chamber from a reserve tank to maintain the continuous coating process.
[0023] In an embodiment, the silicon roller removes the unwanted excess portions of the solution after the cavitation process by squeezing the unwanted portions of the solution from the fabric and wherein the squeezed unwanted portions of the solution is collected at a reserve tank and to the first ultrasonic irradiation chamber.
[0024] In an embodiment, the solution is a nanoparticle solution comprising powders of at least two of nano metal oxides, nano metals, polymers, dodecyl trimethyl ammonium bromide (DTAB) Polyethylenimine (PEI), polyethylene glycol (PEG), and a mixture of the PEG and aqueous solution as a solvent; and wherein the nano particle solution is maintained at a predefined temperature range of 35 - 50 degrees Centigrade.
[0025] In an embodiment, the nanoparticle solution is irradiated inside the first ultrasonic irradiation chamber for a period of 30 min - 45 min before initiating the coating of the fabric to provide uniformity in the nanoparticle solution and to reduce agglomeration in the nanoparticle solution.
[0026] In an embodiment, the management controller is configured to maintain the plurality of heat rollers at a temperature range of 60 deg C to 100 deg C, and to maintain the pH of the solution within a range of 8 to 12 by adding a specific salt at predetermined intervals of time.
[0027] In an embodiment, a visual monitoring system comprising at least one imaging sensor for providing visual data associated with the coated fabric and the plurality of parameters of the apparatus to the management controller, wherein the management controller automatically controls the plurality of parameters of the apparatus based on the visual data.
[0028] In an embodiment, a circulation system comprising a plurality of pipes connected to each of the first fixed ultrasonic transducer and the first adjustable ultrasonic transducer of the first ultrasonic irradiation chamber, and the second fixed ultrasonic transducer and the second adjustable ultrasonic transducer of the second ultrasonic irradiation chamber, wherein the plurality of pipes comprises a coolant for maintain a temperature of each of the first fixed ultrasonic transducer and the first adjustable ultrasonic transducer of the first ultrasonic irradiation chamber, and the second fixed ultrasonic transducer and the second adjustable ultrasonic transducer of the second ultrasonic irradiation chamber at 30 degrees Centigrade.
[0029] In an embodiment, the fabric passes through a plurality of rollers to maintain the fabric unwrinkled during coating the fabric, wherein the plurality of rollers are provided in each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber.
[0030] In an embodiment, each of the first fixed ultrasonic transducer and the first adjustable ultrasonic transducer of the first ultrasonic irradiation chamber, and the second fixed ultrasonic transducer and the second adjustable ultrasonic transducer is provided a power of 700-1200 watts for the cavitation process.
[0031] Accordingly, the embodiments herein provide a method for coating fabric with a solution using an apparatus. The method includes receiving, by a first roller of the apparatus, the fabric to be coated with the solution and coating, by a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers of the apparatus, the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the method includes removing, by a silicon roller of the apparatus, unwanted portions of the solution after the cavitation process and drying, by a drying chamber of the apparatus, the fabric coated with the solution, wherein the drying chamber comprises a plurality of heat rollers. The method also includes managing, by a management controller of the apparatus, a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus and unloading, by a second roller of the apparatus, the dried fabric coated with the solution.
[0032] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF FIGURES
[0033] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0034] FIG. 1A is a block diagram of an apparatus for coating a solution to a fabric by cavitation process, according to the embodiments as disclosed herein;
[0035] FIG. 1B is a perspective view of the apparatus for coating the solution to the fabric by the cavitation process, according to the embodiments as disclosed herein;
[0036] FIG. 2A is an example illustrating an arrangement of multiple miniature piezo-electric transducers of a first fixed ultrasonic transducer unit in a linear arrangement, according to the embodiments as disclosed herein;
[0037] FIG. 2B is an example illustrating the arrangement of the multiple miniature piezo-electric transducers of the first fixed ultrasonic transducer unit in a non-linear arrangement, according to the embodiments as disclosed herein;
[0038] FIG. 3 is an example illustrating a movement of the fabric to be coated in the apparatus during the coating process, according to the embodiments as disclosed herein; and
[0039] FIG. 4 is a flow chart illustrating a method for coating the fabric with the solution by the cavitation process, according to the embodiments as disclosed herein.

DETAILED DESCRIPTION OF INVENTION
[0040] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0041] As is traditional in the field, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions. These blocks, which may be referred to herein as units or modules or the like, are physically implemented by analog or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.
[0042] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
[0043] Accordingly, the embodiments herein provide An apparatus for coating a fabric with a solution. The apparatus includes a first roller for loading the fabric to be coated and a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers for coating the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the apparatus includes a silicon roller for removing unwanted portions of the solution after the cavitation process and a drying chamber comprising a plurality of heat rollers for drying the fabric coated with the solution. The apparatus also includes a management controller for managing a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus; and a second roller for unloading the dried fabric coated with the solution.
[0044] Accordingly, the embodiments herein provide a method for coating fabric with a solution using an apparatus. The method includes receiving, by a first roller of the apparatus, the fabric to be coated with the solution and coating, by a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers of the apparatus, the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the method includes removing, by a silicon roller of the apparatus, unwanted portions of the solution after the cavitation process and drying, by a drying chamber of the apparatus, the fabric coated with the solution, wherein the drying chamber comprises a plurality of heat rollers. The method also includes managing, by a management controller of the apparatus, a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus and unloading, by a second roller of the apparatus, the dried fabric coated with the solution.
[0045] The advantages of the proposed method and the apparatus (1000) includes:
1) high speed of coating of a plurality of textiles
2) highly efficient power transmission in creating MicroJets.
3) a reduced coating time
4) Coating textiles with multiple solution/ nanoparticles or increasing coating speed by using multiple transducers in series combination
5) Coating the multiple layers of fabric at once using a single combination or a combination of multiple ultrasonic plates, thereby decreasing the cost of the fabric and making it affordable.
6) Fabric achieving the inherent properties of inactivating microorganisms such as for example coronavirus.
7) Fabric achieves multiple functional properties when coated with multiple solutions such as UV Resistance, Super hydrophobicity.
8) Fabric Achieves uniform coating by using nonlinear micro transducer arrangement.
9) Strong Adhesion of nanoparticles to fabric - achieving 55 - 120 wash cycles of functional usage.
[0046] Referring now to the drawings, and more particularly to FIG. 1A to FIG. 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0047] FIG. 1A is a block diagram of an apparatus (1000) for coating a solution to a fabric by cavitation process, according to the embodiments as disclosed herein.
[0048] Referring to the FIG. 1A, the apparatus (1000) includes a first roller (100) for loading the fabric to be coated. The apparatus (1000) also includes a first ultrasonic irradiation chamber (200a) which is connected in series with a second ultrasonic irradiation chamber (300a) through which the fabric passes for being coated with the solution by cavitation process. The first ultrasonic irradiation chamber (200a) comprises the solution to be coated. In an example, the first ultrasonic irradiation chamber (200a) might have an inlet to create a gas atmosphere or bubbled gas based on different nanoparticles used. For example, inert gas like Argon may be used.
[0049] In an example, consider that the solution is a nano particle solution including self-disinfecting properties which may be coated to the fabric used to make Personal protective equipment (PPE) suits, gloves, masks etc. The nano particle solution includes powders of at least two of nano metal oxides, nano metals, polymers, dodecyl trimethyl ammonium bromide (DTAB) Polyethylenimine (PEI), polyethylene glycol (PEG) along with a mixture of the PEG and aqueous solution as a solvent. The nano particle solution is maintained at a predefined temperature range of 35 - 50 degrees Centigrade in the first ultrasonic irradiation chamber (200a) to achieve best coating. Further, the nano particle solution is irradiated within the first ultrasonic irradiation chamber (200a) for a period of 30 min - 45 min before initiating the coating of the fabric to provide uniformity in the nano particle solution and to reduce agglomeration in the nano particle solution. The size of the nanoparticles can include 1nm - 1000 nm at weight % of 0.1% - 10% ratios with the surfactants and the solvents mixture.
[0050] In an embodiment, both the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) are used for the coating of the solution.
[0051] In another embodiment, the first ultrasonic irradiation chamber (200a) is used for pre-treatment of the fabric to improve adhesive strength of the coating and the second ultrasonic irradiation chamber (300a) is used for the coating of the solution to the fabric.
[0052] In yet another embodiment, the first ultrasonic irradiation chamber (200a) is used for coating of the solution to the fabric and the second ultrasonic irradiation chamber (300a) is used for cleaning the coated fabric.
[0053] In another embodiment, there each of the first ultrasonic irradiation chambers (200a) of the multiple first ultrasonic irradiation chambers (200a-N) and each of the second ultrasonic irradiation chambers (300a) of the multiple second ultrasonic irradiation chambers (300a-N) may be connected in series. For example, consider that there are 8 ultrasonic irradiation chambers which are connected in series having the same solvent then the fabric is made to pass through each of the 8 ultrasonic irradiation chambers which increase an exposure time of the fabric to the coating process, thereby increasing the efficiency of coating at high rolling speeds. In such an example, each of the ultrasonic irradiation chambers can be provided with the solution for coating the fabric. In another example, consider that the fabric is made to pass through 8 ultrasonic irradiation chambers which are connected in series having the different solvents to add a combination of different material properties to the fabric like antimicrobial cum hydrophobic etc.
[0054] In an embodiment, each of the first ultrasonic irradiation chambers of the multiple first ultrasonic irradiation chambers (200a-N) are vertically stacked one above the other. Similarly, subsequent each second ultrasonic irradiation chambers (300a) of the multiple second ultrasonic irradiation chambers (300a-N) are vertically stacked one above the other. The vertically stacked configuration allows each set of the first ultrasonic irradiation chambers (200a-N) and the subsequent second ultrasonic irradiation chambers (300a-N) to have a different solution and be able to coat a different fabric. The vertically stacked configuration is especially helpful in the manufacture of fabric for preparing face masks which requires multiple layers of coating. Also, the vertically stacked configuration allows the operation of the apparatus (1000) in a small space with very high productivity.
[0055] Further, the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a) has a first fixed ultrasonic transducer unit (220a)/ second fixed ultrasonic transducer unit (320a) located at a bottom portion of the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a) connected in parallel to a first adjustable ultrasonic transducer unit (240a)/ second adjustable ultrasonic transducer unit (340a) located at a top portion of the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a). The first fixed ultrasonic transducer unit (220a)/ second fixed ultrasonic transducer unit (320a) and the first adjustable ultrasonic transducer unit (240a)/ second adjustable ultrasonic transducer unit (340a) are of 1.65-1.8m length, 14-18 cm width and 9.5 to 10cm height. Further, the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a) includes multiple rollers connected to each of the first fixed ultrasonic transducer unit (220a)/ second fixed ultrasonic transducer unit (320a) and the first adjustable ultrasonic transducer unit (240a)/second adjustable ultrasonic transducer unit (340a). These multiple rollers keep the fabric intact during the coating procedure and prevent wrinkles which may lead to patches in the coated fabric. It may be noted that each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a), and the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) is provided a power of 700-1200 watts for the cavitation process. The apparatus (1000) provides 95% of power transmission into the solution cavitation, thus attaining maximum power conversion to create ultrasonic bubbles.
[0056] Furthermore, the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a) is attached to a first spring loaded mechanism (222a) and the second adjustable ultrasonic transducer unit (340a) of the second ultrasonic irradiation chamber (300a) is attached to a second spring loaded mechanism (322a). The first spring loaded mechanism (222a) and the second spring loaded mechanism (322a) are provided to facilitate the loading and locking of the fabric inside the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) respectively. Also, the spring loaded mechanism is used for maintaining a distance between the fabric and the parallel ultrasonic transducers of each of the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) which is maintained within a range of 10mm - 30 mm depending on a type of the fabric and the solution. The spring loaded mechanism makes it easier to vary the distance between the fabric and the parallel ultrasonic transducers based on the fabric. The distance between the fabric and the parallel ultrasonic transducers is a very important parameter in the cavitation process as the distance has to be appropriately set such that the bubbles formed by the cavitation process hits the surface of the fabric covering maximum area. Since the cavitation is a physical process the distance between the fabric and the parallel ultrasonic transducers, and the type of the solution used for coating play an important role in determining the spread of the bubble which hits the surface of the fabric. Further, each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) along with the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) are made of multiple miniature piezo-electric transducers (the construction is explained in details in FIGS.2A-2B).
[0057] The apparatus (1000) also includes multiple silicon rollers (400) which remove unwanted portions of the solution which may be absorbed by the fabric, after the cavitation process by squeezing the unwanted portions of the solution out of the fabric. The squeezed unwanted portion of the solution is collected at a reserve tank below the silicon roller (400) and is re-circulated back to the first ultrasonic irradiation chamber (200a). Therefore, unlike the conventional methods and apparatus, in the proposed apparatus the solution does not deplete during the coating and ensures maximum utilization of the solution. Hence, the proposed method is environmentally friendly and economic. Further, the apparatus (1000) includes a drying chamber (500) which includes multiple heat rollers for drying the fabric coated with the solution.
[0058] The apparatus (1000) also includes a management controller (600) for managing multiple parameters of the apparatus (1000) such as for example but not limited to a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber (200a), pressure of an inert gas within the second ultrasonic irradiation chamber (300a), a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) and a speed of unwinding of the fabric within the apparatus (1000), etc. The management controller (600) is for example a proportional–integral–derivative controller (PID). The management controller (600) is configured to maintain constant speed of the textile for uniform coatings. A motor construction mechanism has been utilized to prevent sudden jerks and maintain a constant speed. The constant speed of the fabric can be for example but not limited to the range of 0.0066mtr/sec to 0.083mtr/sec.
[0059] The first ultrasonic irradiation chamber (200a) is provided with a level switch which measures a level of the solution in the first ultrasonic irradiation chamber (200a) and sends the data to the management controller (600). When the management controller (600) determines that the solution is below a predefined level, the management controller (600) automatically refills the solution in the first ultrasonic irradiation chamber (200a) from a reserve tank to maintain the continuous coating process. A volume of 45 liters of the solution is constantly maintained in the first ultrasonic irradiation chamber (200a).
[0060] The management controller (600) is configured to maintain the multiple heat rollers at a temperature range of 60 deg C to 100 deg C, and to maintain the pH of the solution within a range of 8 to 12 by adding a specific salt at predetermined intervals of time.
[0061] The apparatus (1000) also includes a circulation system (900) which includes multiple pipes connected to each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a), and the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) of the second ultrasonic irradiation chamber (300a). A coolant is made to continuously flow through the multiple pipes to maintain a temperature of each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a), and the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) of the second ultrasonic irradiation chamber (300a) at 30 degrees Centigrade. The circulation system (900) prevents overheating of the apparatus (1000) which extends an operation time of the apparatus (1000). The apparatus (1000) can provide continuous operation for about 7 days with the circulation system (900) in place.
[0062] The apparatus (1000) also includes a visual monitoring system (800) for overseeing the coating process. The visual monitoring system (800) includes imaging sensors/cameras for providing visual data associated with the coated fabric and the plurality of parameters of the apparatus (1000) to the management controller (600). The visual monitoring system (800) may be fit at a location between the second ultrasonic irradiation chamber (300a) and the silicon roller (400) where the coated fabric is visible. The management controller (600) compares the received images of the coated fabric with stored images of the coated fabric to determine if there are any patches, wrinkles, etc. and automatically controls the plurality of parameters of the apparatus (1000) based on the visual data.
[0063] Finally, the apparatus (1000) includes a second roller (700) for unloading the dried fabric coated with the solution.
[0064] Although the FIG. 1A shows the hardware elements of the apparatus (1000) but it is to be understood that other embodiments are not limited thereon. In other embodiments, the apparatus (1000) may include less or more number of elements. Further, the labels or names of the elements are used only for illustrative purposes and does not limit the scope of the invention. One or more components can be combined together to perform the same or substantially similar function.
[0065] FIG. 1B is a perspective view of the apparatus (1000) for coating the solution to the fabric by the cavitation process, according to the embodiments as disclosed herein.
[0066] Referring to the FIG. 1B, the perspective view of the apparatus (1000) is provided which illustrates the movement of the fabric which needs to be coated. The first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) has length in the range of 1.82m to 1.85m, width in the range of 33cm to 37 cm, 21.5 cm height and volume in the range of 0.13 to 0.14 cubic meter.
[0067] The method of coating the fabric with the nanoparticles by the apparatus (1000) includes: The fabric passes through the first ultrasonic irradiation chamber (200a) which is filled with nano-particles solution and the second ultrasonic irradiation chamber (300a). The nano-particles have a capability to induce high reactive oxygen species (ROS) mechanism required for inactivating coronavirus through oxidative stress. The size of the nanoparticles varies in arrange of 1-1000 nm. The solvent is an aqueous or any other solvent that is necessary for the specific nanoparticles.
[0068] Further, as the fabric moves through the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a), the piezoelectric ultrasonic transducers which are running at high frequencies, generate bubbles in the solvent that vibrate at high frequencies. This is called the cavitation process. Micro jets and shock waves produced by the ultrasonic cavitation drive the nano-particles in very high velocities towards a substrate and as these bubbles hit a surface (i.e., the fabric), the bubbles burst, thus resulting in the nanoparticles adhering strongly to the fabric. The adherence of the bubble to the fabric can either be a physical or chemical bond. The rollers help keep the fabric stiff while in the ultrasonic chamber and can be optimized for fabrics of different grams per square meter (GSM) values. Inert gases like Argon are used to maintain pressure on the solvent surface to facilitate the cavitation.
[0069] FIG. 2A is an example illustrating an arrangement of multiple miniature piezo-electric transducers of a first fixed ultrasonic transducer unit (220a) in a linear arrangement, according to the embodiments as disclosed herein.
[0070] Referring to the FIG. 2A, each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) along with the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) are made of multiple miniature piezo-electric transducers. The multiple miniature piezo-electric transducers embedded in the hollow box in the linear arrangement (as shown in the FIG. 2A). Further, in the linear arrangement a center-to-center distance of 7 cm is provided is maintained between the multiple miniature piezo-electric transducers. The multiple miniature piezo-electric transducers are arranged such that maximum resonant frequencies of a range of 20- 40 KHz is obtained for the hollow box. The hollow box may be made of stainless steel or Titanium.
[0071] Appropriate arrangement of the multiple miniature piezo-electric transducers ensures uniform micro jets in the nano-particles solution which results in uniform coating of the solution on the fabric. However, if the center-to-center distance is not appropriately provided, then in the linear arrangement of the multiple miniature piezo-electric transducers, non-uniformly coated or uncoated patches may be produced in the fabric after coating.
[0072] FIG. 2B is an example illustrating the arrangement of the multiple miniature piezo-electric transducers of the first fixed ultrasonic transducer unit (220a) in a non-linear arrangement, according to the embodiments as disclosed herein.
[0073] Referring to the FIG. 2A in conjunction to the FIG. 2B, in the non-linear arrangement the center-to-center distance of 3.5 cm is provided between the multiple miniature piezo-electric transducers. The non-linear arrangement may be for example but not limited to Zigzag arrangement. The non-linear arrangement of the multiple miniature piezo-electric transducers ensures uniform coating of the solution throughout the fabric without creating the un-coated patches.
[0074] FIG. 3 is an example illustrating a movement of the fabric to be coated in the apparatus during the coating process, according to the embodiments as disclosed herein.
[0075] Referring to the FIG. 3, the movement of the fabric between the first ultrasonic irradiation chamber (200a), the second ultrasonic irradiation chamber (300a), the silicon roller (400) and the second roller (700) where the coated fabric is unloaded. The fabric may be for example but not limited to a textile, a cloth, paper, tissue, plastic, and the like. Also, textiles with different Gram Square Measurement (GSM)s can be coated using the apparatus (1000). The GSM of the textile can be between 30-300 GSM. The apparatus (1000) can also be used to coat different types of textiles like cotton, Non-Woven Fabric, Yarns, etc. The fabric of width in the range of 30 cm to 2 meters can be coated by the apparatus (1000). Further, this may not be considered as a restriction and the apparatus (1000) can be modified to increase the width of the fabric.
[0076] Further, the coating process is not limited to coating of nanoparticles solution and the same process may be extended to dyeing of the fabrics where the solution will be a dye.
[0077] FIG. 4 is a flow chart 400 illustrating a method for coating the fabric with the solution by the cavitation process, according to the embodiments as disclosed herein.
[0078] Referring to the FIG. 4, at step 402, the method includes receiving the fabric to be coated with the solution. At step 404, the method includes coating the fabric with the solution by cavitation process. At step 406, the method includes removing unwanted portions of the solution after the cavitation process. At step 408, the method includes drying the fabric coated with the solution. At step 410, the method includes managing plurality of parameters of the apparatus. At step 412, the method includes unloading the dried fabric coated with the solution.
[0079] The various actions, acts, blocks, steps, or the like in the method may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.
[0080] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the embodiments as described herein.
,CLAIMS:The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

FIELD OF INVENTION
[0001] The embodiments herein relate to coating of surfaces. More particularly relates to a method and an apparatus for coating a fabric with a solution to incorporate specific features to the fabric by cavitation. The present application is based on, and claims priority from an Indian Application Number 202041019629 filed on 8th May 2020 the disclosure of which is hereby incorporated by reference herein

BACKGROUND OF THE INVENTION
[0002] In general, with advancement in textile technology has resulted in improved fabrics and textiles. Antibacterial, antimicrobial or antiviral fabrics are widely used for production of outdoor clothes, under-wear, bed-linen, bandages, etc. However, the process of manufacturing may be time consuming and expensive. Further, in a pandemic situation like the one witnessed since the 2020 COVID-19 pandemic the demand for the improved fabrics and textiles to protect the users may be accompanied with a need to slow down the rate of transmission of virus to break the chain. One such possibility of slowing down the rate of transmission of the virus is by using self-disinfecting surfaces which can inactivate the virus on most surfaces which will eventually slow the transmission rate.
[0003] Some of the conventional coatings to incorporate self-disinfectant properties include nanoparticles coating which are coated by ultrasonic irradiation on the surface of various substrates including ceramics and polymers. Such deposition results in a highly homogenous surface coating and high adhesions. Micro jets and shock waves produced by the ultrasonic cavitation drive the nanoparticles in very high velocities towards a substrate and the velocities are high enough to adhere strongly either chemically or physically depending on the substrate and particles used. This similar process can be used for coating of the textiles like cotton, nylon, polyester etc. However the previous research or laboratory experiments suggest that it takes about one hour to coat 1 meter of a textile. This is a major drawback in commercial setup where the textile needs to be coated at higher speeds. Another drawback of the process is that the laboratory setups can only coat one textile after another and do not have the ability to coat different textiles at the same time. So the coating process might take days to weeks for completion before the textiles can be used for any commercial purposes. These delays also add a lot of cost to the overall finished product prepared using the coated textiles.
[0004] Thus, it is desired to address the above mentioned disadvantages or other shortcomings or at least provide a useful alternative.

OBJECT OF INVENTION
[0005] The principal object of the embodiments herein is to provide a method and an apparatus for coating a fabric with a solution to incorporate specific features to the fabric such as self- disinfecting features by cavitation process using multiple ultrasonic irradiation chambers through which the fabric is passed to achieve the coating. The apparatus and the method enable fast, efficient and economic coating mechanisms especially for bulk manufacturing within a short period of time.
[0006] Another object of the embodiments herein is to provide an environmentally friendly and power efficient method for coating the fabrics. The apparatus and method provide various mechanisms for collection of unwanted solutions from the fabric which is fed back to a reserve tank and reused for coating.
SUMMARY
[0007] Accordingly, the embodiments herein provide An apparatus for coating a fabric with a solution. The apparatus includes a first roller for loading the fabric to be coated and a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers for coating the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the apparatus includes a silicon roller for removing unwanted portions of the solution after the cavitation process and a drying chamber comprising a plurality of heat rollers for drying the fabric coated with the solution. The apparatus also includes a management controller for managing a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus; and a second roller for unloading the dried fabric coated with the solution.
[0008] In an embodiment, the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber is of 1.82m to 1.85m length, 33cm to 37 cm width, 21.5 cm height and 0.13 to 0.14 cubic meter volume.
[0009] In an embodiment, the first ultrasonic irradiation chamber comprises a first fixed ultrasonic transducer unit located at a bottom portion of the first ultrasonic irradiation chamber connected in parallel to a first adjustable ultrasonic transducer unit located at a top portion of the first ultrasonic irradiation chamber, and wherein the first fixed ultrasonic transducer unit and the first adjustable ultrasonic transducer unit are of 1.65-1.8m length, 14-18 cm width and 9.5 to 10cm height.
[0010] In an embodiment, each of the first fixed ultrasonic transducer unit and the first adjustable ultrasonic transducer unit comprises a plurality of miniature piezo-electric transducers provided at a center-to-center distance between the plurality of miniature piezo-electric transducers one of: 7 cm in a linear arrangement and 3.5 cm in a non-linear arrangement.
[0011] In an embodiment, the plurality of miniature piezo-electric transducers is embedded in a hollow box to provide maximum resonant frequencies of range of 20- 40 KHz for the hollow box and to provide uniform micro jets in the solution for uniform coating of the fabric passed through the first irradiation chamber.
[0012] In an embodiment, the second ultrasonic irradiation chamber comprises a second fixed ultrasonic transducer unit located at a bottom portion of the second ultrasonic irradiation chamber connected in parallel to a second adjustable ultrasonic transducer unit located at a top portion of the second ultrasonic irradiation chamber, and wherein the second fixed ultrasonic transducer unit and the second adjustable ultrasonic transducer unit are of 1.65-1.8m length, 14-18 cm width and 9.5 to 10cm height.
[0013] In an embodiment, each of the second fixed ultrasonic transducer unit and the second adjustable ultrasonic transducer unit comprises a plurality of miniature piezo-electric transducers provided a center-to-center distance between the plurality of miniature piezo-electric transducers one of: 7 cm in a linear arrangement and 3.5 cm in a non-linear arrangement.
[0014] In an embodiment, the plurality of miniature piezo-electric transducers is embedded in a hollow box to provide maximum resonant frequencies of range of 20- 40 KHz for the hollow box and to provide uniform micro jets in the solution for uniform coating of the fabric passed through the second ultrasonic irradiation chamber.
[0015] In an embodiment, the fabric of width in a range of 30 cm to 2 meters is coated by the apparatus.
[0016] In an embodiment, each of the first ultrasonic irradiation chambers of the plurality of first ultrasonic irradiation chambers are vertically stacked, and each of the second ultrasonic irradiation chambers of the plurality of second ultrasonic irradiation chambers are vertically stacked.
[0017] In an embodiment, each set of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber comprises a different solution for coating a different fabric.
[0018] In an embodiment, each of the first ultrasonic irradiation chambers of the plurality of first ultrasonic irradiation chambers and each of the second ultrasonic irradiation chambers of the plurality of second ultrasonic irradiation chambers are connected in series, and wherein each of the first ultrasonic irradiation chambers of the plurality of first ultrasonic irradiation chambers comprises the solution for coating the fabric to increase an exposure time of the fabric to the solution at high rolling speeds.
[0019] In an embodiment, the first adjustable ultrasonic transducer unit of the first ultrasonic irradiation chamber is attached to a first spring loaded mechanism and the second adjustable ultrasonic transducer unit of the second ultrasonic irradiation chamber is attached to a second spring loaded mechanism.
[0020] In an embodiment, the first spring loaded mechanism and the second spring loaded mechanism is used for loading and locking the fabric inside the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber respectively; and for maintaining a distance between the fabric and the parallel ultrasonic transducers of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber.
[0021] In an embodiment, the distance between the fabric and the parallel ultrasonic transducers of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber is maintained at a range of 10mm - 30 mm depending on the type of the fabric and the solution.
[0022] In an embodiment, the management controller is configured to receive a measurement from a level switch at the first ultrasonic irradiation chamber indicating a level of the solution to be coated on the fabric and determine that the solution in the first ultrasonic irradiation chamber is below a predefined level. Further, the management controller is configured to automatically refill the solution in the first ultrasonic irradiation chamber from a reserve tank to maintain the continuous coating process.
[0023] In an embodiment, the silicon roller removes the unwanted excess portions of the solution after the cavitation process by squeezing the unwanted portions of the solution from the fabric and wherein the squeezed unwanted portions of the solution is collected at a reserve tank and to the first ultrasonic irradiation chamber.
[0024] In an embodiment, the solution is a nanoparticle solution comprising powders of at least two of nano metal oxides, nano metals, polymers, dodecyl trimethyl ammonium bromide (DTAB) Polyethylenimine (PEI), polyethylene glycol (PEG), and a mixture of the PEG and aqueous solution as a solvent; and wherein the nano particle solution is maintained at a predefined temperature range of 35 - 50 degrees Centigrade.
[0025] In an embodiment, the nanoparticle solution is irradiated inside the first ultrasonic irradiation chamber for a period of 30 min - 45 min before initiating the coating of the fabric to provide uniformity in the nanoparticle solution and to reduce agglomeration in the nanoparticle solution.
[0026] In an embodiment, the management controller is configured to maintain the plurality of heat rollers at a temperature range of 60 deg C to 100 deg C, and to maintain the pH of the solution within a range of 8 to 12 by adding a specific salt at predetermined intervals of time.
[0027] In an embodiment, a visual monitoring system comprising at least one imaging sensor for providing visual data associated with the coated fabric and the plurality of parameters of the apparatus to the management controller, wherein the management controller automatically controls the plurality of parameters of the apparatus based on the visual data.
[0028] In an embodiment, a circulation system comprising a plurality of pipes connected to each of the first fixed ultrasonic transducer and the first adjustable ultrasonic transducer of the first ultrasonic irradiation chamber, and the second fixed ultrasonic transducer and the second adjustable ultrasonic transducer of the second ultrasonic irradiation chamber, wherein the plurality of pipes comprises a coolant for maintain a temperature of each of the first fixed ultrasonic transducer and the first adjustable ultrasonic transducer of the first ultrasonic irradiation chamber, and the second fixed ultrasonic transducer and the second adjustable ultrasonic transducer of the second ultrasonic irradiation chamber at 30 degrees Centigrade.
[0029] In an embodiment, the fabric passes through a plurality of rollers to maintain the fabric unwrinkled during coating the fabric, wherein the plurality of rollers are provided in each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber.
[0030] In an embodiment, each of the first fixed ultrasonic transducer and the first adjustable ultrasonic transducer of the first ultrasonic irradiation chamber, and the second fixed ultrasonic transducer and the second adjustable ultrasonic transducer is provided a power of 700-1200 watts for the cavitation process.
[0031] Accordingly, the embodiments herein provide a method for coating fabric with a solution using an apparatus. The method includes receiving, by a first roller of the apparatus, the fabric to be coated with the solution and coating, by a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers of the apparatus, the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the method includes removing, by a silicon roller of the apparatus, unwanted portions of the solution after the cavitation process and drying, by a drying chamber of the apparatus, the fabric coated with the solution, wherein the drying chamber comprises a plurality of heat rollers. The method also includes managing, by a management controller of the apparatus, a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus and unloading, by a second roller of the apparatus, the dried fabric coated with the solution.
[0032] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the scope thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF FIGURES
[0033] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0034] FIG. 1A is a block diagram of an apparatus for coating a solution to a fabric by cavitation process, according to the embodiments as disclosed herein;
[0035] FIG. 1B is a perspective view of the apparatus for coating the solution to the fabric by the cavitation process, according to the embodiments as disclosed herein;
[0036] FIG. 2A is an example illustrating an arrangement of multiple miniature piezo-electric transducers of a first fixed ultrasonic transducer unit in a linear arrangement, according to the embodiments as disclosed herein;
[0037] FIG. 2B is an example illustrating the arrangement of the multiple miniature piezo-electric transducers of the first fixed ultrasonic transducer unit in a non-linear arrangement, according to the embodiments as disclosed herein;
[0038] FIG. 3 is an example illustrating a movement of the fabric to be coated in the apparatus during the coating process, according to the embodiments as disclosed herein; and
[0039] FIG. 4 is a flow chart illustrating a method for coating the fabric with the solution by the cavitation process, according to the embodiments as disclosed herein.

DETAILED DESCRIPTION OF INVENTION
[0040] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0041] As is traditional in the field, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions. These blocks, which may be referred to herein as units or modules or the like, are physically implemented by analog or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by firmware. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the disclosure. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the disclosure.
[0042] The accompanying drawings are used to help easily understand various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawings. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
[0043] Accordingly, the embodiments herein provide An apparatus for coating a fabric with a solution. The apparatus includes a first roller for loading the fabric to be coated and a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers for coating the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the apparatus includes a silicon roller for removing unwanted portions of the solution after the cavitation process and a drying chamber comprising a plurality of heat rollers for drying the fabric coated with the solution. The apparatus also includes a management controller for managing a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus; and a second roller for unloading the dried fabric coated with the solution.
[0044] Accordingly, the embodiments herein provide a method for coating fabric with a solution using an apparatus. The method includes receiving, by a first roller of the apparatus, the fabric to be coated with the solution and coating, by a first ultrasonic irradiation chamber of a plurality of first ultrasonic irradiation chambers connected in series with a second ultrasonic irradiation chamber of a plurality of second ultrasonic irradiation chambers of the apparatus, the fabric with the solution by cavitation process. The first ultrasonic irradiation chamber comprises the solution to be coated. Further, the method includes removing, by a silicon roller of the apparatus, unwanted portions of the solution after the cavitation process and drying, by a drying chamber of the apparatus, the fabric coated with the solution, wherein the drying chamber comprises a plurality of heat rollers. The method also includes managing, by a management controller of the apparatus, a plurality of parameters of the apparatus, wherein the plurality of parameters comprises at least one of a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber, pressure of an inert gas within the second ultrasonic irradiation chamber, a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber and the second ultrasonic irradiation chamber and a speed of unwinding of the fabric within the apparatus and unloading, by a second roller of the apparatus, the dried fabric coated with the solution.
[0045] The advantages of the proposed method and the apparatus (1000) includes:
1) high speed of coating of a plurality of textiles
2) highly efficient power transmission in creating MicroJets.
3) a reduced coating time
4) Coating textiles with multiple solution/ nanoparticles or increasing coating speed by using multiple transducers in series combination
5) Coating the multiple layers of fabric at once using a single combination or a combination of multiple ultrasonic plates, thereby decreasing the cost of the fabric and making it affordable.
6) Fabric achieving the inherent properties of inactivating microorganisms such as for example coronavirus.
7) Fabric achieves multiple functional properties when coated with multiple solutions such as UV Resistance, Super hydrophobicity.
8) Fabric Achieves uniform coating by using nonlinear micro transducer arrangement.
9) Strong Adhesion of nanoparticles to fabric - achieving 55 - 120 wash cycles of functional usage.
[0046] Referring now to the drawings, and more particularly to FIG. 1A to FIG. 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0047] FIG. 1A is a block diagram of an apparatus (1000) for coating a solution to a fabric by cavitation process, according to the embodiments as disclosed herein.
[0048] Referring to the FIG. 1A, the apparatus (1000) includes a first roller (100) for loading the fabric to be coated. The apparatus (1000) also includes a first ultrasonic irradiation chamber (200a) which is connected in series with a second ultrasonic irradiation chamber (300a) through which the fabric passes for being coated with the solution by cavitation process. The first ultrasonic irradiation chamber (200a) comprises the solution to be coated. In an example, the first ultrasonic irradiation chamber (200a) might have an inlet to create a gas atmosphere or bubbled gas based on different nanoparticles used. For example, inert gas like Argon may be used.
[0049] In an example, consider that the solution is a nano particle solution including self-disinfecting properties which may be coated to the fabric used to make Personal protective equipment (PPE) suits, gloves, masks etc. The nano particle solution includes powders of at least two of nano metal oxides, nano metals, polymers, dodecyl trimethyl ammonium bromide (DTAB) Polyethylenimine (PEI), polyethylene glycol (PEG) along with a mixture of the PEG and aqueous solution as a solvent. The nano particle solution is maintained at a predefined temperature range of 35 - 50 degrees Centigrade in the first ultrasonic irradiation chamber (200a) to achieve best coating. Further, the nano particle solution is irradiated within the first ultrasonic irradiation chamber (200a) for a period of 30 min - 45 min before initiating the coating of the fabric to provide uniformity in the nano particle solution and to reduce agglomeration in the nano particle solution. The size of the nanoparticles can include 1nm - 1000 nm at weight % of 0.1% - 10% ratios with the surfactants and the solvents mixture.
[0050] In an embodiment, both the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) are used for the coating of the solution.
[0051] In another embodiment, the first ultrasonic irradiation chamber (200a) is used for pre-treatment of the fabric to improve adhesive strength of the coating and the second ultrasonic irradiation chamber (300a) is used for the coating of the solution to the fabric.
[0052] In yet another embodiment, the first ultrasonic irradiation chamber (200a) is used for coating of the solution to the fabric and the second ultrasonic irradiation chamber (300a) is used for cleaning the coated fabric.
[0053] In another embodiment, there each of the first ultrasonic irradiation chambers (200a) of the multiple first ultrasonic irradiation chambers (200a-N) and each of the second ultrasonic irradiation chambers (300a) of the multiple second ultrasonic irradiation chambers (300a-N) may be connected in series. For example, consider that there are 8 ultrasonic irradiation chambers which are connected in series having the same solvent then the fabric is made to pass through each of the 8 ultrasonic irradiation chambers which increase an exposure time of the fabric to the coating process, thereby increasing the efficiency of coating at high rolling speeds. In such an example, each of the ultrasonic irradiation chambers can be provided with the solution for coating the fabric. In another example, consider that the fabric is made to pass through 8 ultrasonic irradiation chambers which are connected in series having the different solvents to add a combination of different material properties to the fabric like antimicrobial cum hydrophobic etc.
[0054] In an embodiment, each of the first ultrasonic irradiation chambers of the multiple first ultrasonic irradiation chambers (200a-N) are vertically stacked one above the other. Similarly, subsequent each second ultrasonic irradiation chambers (300a) of the multiple second ultrasonic irradiation chambers (300a-N) are vertically stacked one above the other. The vertically stacked configuration allows each set of the first ultrasonic irradiation chambers (200a-N) and the subsequent second ultrasonic irradiation chambers (300a-N) to have a different solution and be able to coat a different fabric. The vertically stacked configuration is especially helpful in the manufacture of fabric for preparing face masks which requires multiple layers of coating. Also, the vertically stacked configuration allows the operation of the apparatus (1000) in a small space with very high productivity.
[0055] Further, the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a) has a first fixed ultrasonic transducer unit (220a)/ second fixed ultrasonic transducer unit (320a) located at a bottom portion of the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a) connected in parallel to a first adjustable ultrasonic transducer unit (240a)/ second adjustable ultrasonic transducer unit (340a) located at a top portion of the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a). The first fixed ultrasonic transducer unit (220a)/ second fixed ultrasonic transducer unit (320a) and the first adjustable ultrasonic transducer unit (240a)/ second adjustable ultrasonic transducer unit (340a) are of 1.65-1.8m length, 14-18 cm width and 9.5 to 10cm height. Further, the first ultrasonic irradiation chamber (200a)/ second ultrasonic irradiation chamber (300a) includes multiple rollers connected to each of the first fixed ultrasonic transducer unit (220a)/ second fixed ultrasonic transducer unit (320a) and the first adjustable ultrasonic transducer unit (240a)/second adjustable ultrasonic transducer unit (340a). These multiple rollers keep the fabric intact during the coating procedure and prevent wrinkles which may lead to patches in the coated fabric. It may be noted that each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a), and the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) is provided a power of 700-1200 watts for the cavitation process. The apparatus (1000) provides 95% of power transmission into the solution cavitation, thus attaining maximum power conversion to create ultrasonic bubbles.
[0056] Furthermore, the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a) is attached to a first spring loaded mechanism (222a) and the second adjustable ultrasonic transducer unit (340a) of the second ultrasonic irradiation chamber (300a) is attached to a second spring loaded mechanism (322a). The first spring loaded mechanism (222a) and the second spring loaded mechanism (322a) are provided to facilitate the loading and locking of the fabric inside the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) respectively. Also, the spring loaded mechanism is used for maintaining a distance between the fabric and the parallel ultrasonic transducers of each of the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) which is maintained within a range of 10mm - 30 mm depending on a type of the fabric and the solution. The spring loaded mechanism makes it easier to vary the distance between the fabric and the parallel ultrasonic transducers based on the fabric. The distance between the fabric and the parallel ultrasonic transducers is a very important parameter in the cavitation process as the distance has to be appropriately set such that the bubbles formed by the cavitation process hits the surface of the fabric covering maximum area. Since the cavitation is a physical process the distance between the fabric and the parallel ultrasonic transducers, and the type of the solution used for coating play an important role in determining the spread of the bubble which hits the surface of the fabric. Further, each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) along with the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) are made of multiple miniature piezo-electric transducers (the construction is explained in details in FIGS.2A-2B).
[0057] The apparatus (1000) also includes multiple silicon rollers (400) which remove unwanted portions of the solution which may be absorbed by the fabric, after the cavitation process by squeezing the unwanted portions of the solution out of the fabric. The squeezed unwanted portion of the solution is collected at a reserve tank below the silicon roller (400) and is re-circulated back to the first ultrasonic irradiation chamber (200a). Therefore, unlike the conventional methods and apparatus, in the proposed apparatus the solution does not deplete during the coating and ensures maximum utilization of the solution. Hence, the proposed method is environmentally friendly and economic. Further, the apparatus (1000) includes a drying chamber (500) which includes multiple heat rollers for drying the fabric coated with the solution.
[0058] The apparatus (1000) also includes a management controller (600) for managing multiple parameters of the apparatus (1000) such as for example but not limited to a frequency required for the cavitation of the solution, a power required for the cavitation of the solution, a pH of the solution, pressure of an inert gas within the first ultrasonic irradiation chamber (200a), pressure of an inert gas within the second ultrasonic irradiation chamber (300a), a distance between the fabric a top portion of each of the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) and a speed of unwinding of the fabric within the apparatus (1000), etc. The management controller (600) is for example a proportional–integral–derivative controller (PID). The management controller (600) is configured to maintain constant speed of the textile for uniform coatings. A motor construction mechanism has been utilized to prevent sudden jerks and maintain a constant speed. The constant speed of the fabric can be for example but not limited to the range of 0.0066mtr/sec to 0.083mtr/sec.
[0059] The first ultrasonic irradiation chamber (200a) is provided with a level switch which measures a level of the solution in the first ultrasonic irradiation chamber (200a) and sends the data to the management controller (600). When the management controller (600) determines that the solution is below a predefined level, the management controller (600) automatically refills the solution in the first ultrasonic irradiation chamber (200a) from a reserve tank to maintain the continuous coating process. A volume of 45 liters of the solution is constantly maintained in the first ultrasonic irradiation chamber (200a).
[0060] The management controller (600) is configured to maintain the multiple heat rollers at a temperature range of 60 deg C to 100 deg C, and to maintain the pH of the solution within a range of 8 to 12 by adding a specific salt at predetermined intervals of time.
[0061] The apparatus (1000) also includes a circulation system (900) which includes multiple pipes connected to each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a), and the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) of the second ultrasonic irradiation chamber (300a). A coolant is made to continuously flow through the multiple pipes to maintain a temperature of each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) of the first ultrasonic irradiation chamber (200a), and the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) of the second ultrasonic irradiation chamber (300a) at 30 degrees Centigrade. The circulation system (900) prevents overheating of the apparatus (1000) which extends an operation time of the apparatus (1000). The apparatus (1000) can provide continuous operation for about 7 days with the circulation system (900) in place.
[0062] The apparatus (1000) also includes a visual monitoring system (800) for overseeing the coating process. The visual monitoring system (800) includes imaging sensors/cameras for providing visual data associated with the coated fabric and the plurality of parameters of the apparatus (1000) to the management controller (600). The visual monitoring system (800) may be fit at a location between the second ultrasonic irradiation chamber (300a) and the silicon roller (400) where the coated fabric is visible. The management controller (600) compares the received images of the coated fabric with stored images of the coated fabric to determine if there are any patches, wrinkles, etc. and automatically controls the plurality of parameters of the apparatus (1000) based on the visual data.
[0063] Finally, the apparatus (1000) includes a second roller (700) for unloading the dried fabric coated with the solution.
[0064] Although the FIG. 1A shows the hardware elements of the apparatus (1000) but it is to be understood that other embodiments are not limited thereon. In other embodiments, the apparatus (1000) may include less or more number of elements. Further, the labels or names of the elements are used only for illustrative purposes and does not limit the scope of the invention. One or more components can be combined together to perform the same or substantially similar function.
[0065] FIG. 1B is a perspective view of the apparatus (1000) for coating the solution to the fabric by the cavitation process, according to the embodiments as disclosed herein.
[0066] Referring to the FIG. 1B, the perspective view of the apparatus (1000) is provided which illustrates the movement of the fabric which needs to be coated. The first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a) has length in the range of 1.82m to 1.85m, width in the range of 33cm to 37 cm, 21.5 cm height and volume in the range of 0.13 to 0.14 cubic meter.
[0067] The method of coating the fabric with the nanoparticles by the apparatus (1000) includes: The fabric passes through the first ultrasonic irradiation chamber (200a) which is filled with nano-particles solution and the second ultrasonic irradiation chamber (300a). The nano-particles have a capability to induce high reactive oxygen species (ROS) mechanism required for inactivating coronavirus through oxidative stress. The size of the nanoparticles varies in arrange of 1-1000 nm. The solvent is an aqueous or any other solvent that is necessary for the specific nanoparticles.
[0068] Further, as the fabric moves through the first ultrasonic irradiation chamber (200a) and the second ultrasonic irradiation chamber (300a), the piezoelectric ultrasonic transducers which are running at high frequencies, generate bubbles in the solvent that vibrate at high frequencies. This is called the cavitation process. Micro jets and shock waves produced by the ultrasonic cavitation drive the nano-particles in very high velocities towards a substrate and as these bubbles hit a surface (i.e., the fabric), the bubbles burst, thus resulting in the nanoparticles adhering strongly to the fabric. The adherence of the bubble to the fabric can either be a physical or chemical bond. The rollers help keep the fabric stiff while in the ultrasonic chamber and can be optimized for fabrics of different grams per square meter (GSM) values. Inert gases like Argon are used to maintain pressure on the solvent surface to facilitate the cavitation.
[0069] FIG. 2A is an example illustrating an arrangement of multiple miniature piezo-electric transducers of a first fixed ultrasonic transducer unit (220a) in a linear arrangement, according to the embodiments as disclosed herein.
[0070] Referring to the FIG. 2A, each of the first fixed ultrasonic transducer unit (220a) and the first adjustable ultrasonic transducer unit (240a) along with the second fixed ultrasonic transducer unit (320a) and the second adjustable ultrasonic transducer unit (340a) are made of multiple miniature piezo-electric transducers. The multiple miniature piezo-electric transducers embedded in the hollow box in the linear arrangement (as shown in the FIG. 2A). Further, in the linear arrangement a center-to-center distance of 7 cm is provided is maintained between the multiple miniature piezo-electric transducers. The multiple miniature piezo-electric transducers are arranged such that maximum resonant frequencies of a range of 20- 40 KHz is obtained for the hollow box. The hollow box may be made of stainless steel or Titanium.
[0071] Appropriate arrangement of the multiple miniature piezo-electric transducers ensures uniform micro jets in the nano-particles solution which results in uniform coating of the solution on the fabric. However, if the center-to-center distance is not appropriately provided, then in the linear arrangement of the multiple miniature piezo-electric transducers, non-uniformly coated or uncoated patches may be produced in the fabric after coating.
[0072] FIG. 2B is an example illustrating the arrangement of the multiple miniature piezo-electric transducers of the first fixed ultrasonic transducer unit (220a) in a non-linear arrangement, according to the embodiments as disclosed herein.
[0073] Referring to the FIG. 2A in conjunction to the FIG. 2B, in the non-linear arrangement the center-to-center distance of 3.5 cm is provided between the multiple miniature piezo-electric transducers. The non-linear arrangement may be for example but not limited to Zigzag arrangement. The non-linear arrangement of the multiple miniature piezo-electric transducers ensures uniform coating of the solution throughout the fabric without creating the un-coated patches.
[0074] FIG. 3 is an example illustrating a movement of the fabric to be coated in the apparatus during the coating process, according to the embodiments as disclosed herein.
[0075] Referring to the FIG. 3, the movement of the fabric between the first ultrasonic irradiation chamber (200a), the second ultrasonic irradiation chamber (300a), the silicon roller (400) and the second roller (700) where the coated fabric is unloaded. The fabric may be for example but not limited to a textile, a cloth, paper, tissue, plastic, and the like. Also, textiles with different Gram Square Measurement (GSM)s can be coated using the apparatus (1000). The GSM of the textile can be between 30-300 GSM. The apparatus (1000) can also be used to coat different types of textiles like cotton, Non-Woven Fabric, Yarns, etc. The fabric of width in the range of 30 cm to 2 meters can be coated by the apparatus (1000). Further, this may not be considered as a restriction and the apparatus (1000) can be modified to increase the width of the fabric.
[0076] Further, the coating process is not limited to coating of nanoparticles solution and the same process may be extended to dyeing of the fabrics where the solution will be a dye.
[0077] FIG. 4 is a flow chart 400 illustrating a method for coating the fabric with the solution by the cavitation process, according to the embodiments as disclosed herein.
[0078] Referring to the FIG. 4, at step 402, the method includes receiving the fabric to be coated with the solution. At step 404, the method includes coating the fabric with the solution by cavitation process. At step 406, the method includes removing unwanted portions of the solution after the cavitation process. At step 408, the method includes drying the fabric coated with the solution. At step 410, the method includes managing plurality of parameters of the apparatus. At step 412, the method includes unloading the dried fabric coated with the solution.
[0079] The various actions, acts, blocks, steps, or the like in the method may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some of the actions, acts, blocks, steps, or the like may be omitted, added, modified, skipped, or the like without departing from the scope of the invention.
[0080] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the embodiments as described herein.