Patent Description:
The present disclosure relates to air management systems. More specifically, the present disclosure relates to protection of ducts in air management systems.

Pressurized aircraft have integrated air management systems to provide a pressurized environment, fresh air transfer, recycling, heating, and air conditioning to maintain a comfortable, safe environment for occupants for extended periods of time. Air recycling and replacing stale air requires continuous scrubbing for cleanliness to reduce airborne dust, dirt, odors, viruses, spores, and bacteria. This cleaning or scrubbing of the air is typically performed via physical, electrostatic or chemical filtration, such as via a high efficiency particulate air (HEPA) filter. However, bacteria and dirt can accumulate on the filter, benefitting from cleaning or replacement of the filters themselves. <CIT> describes an adsorptive photocatalytic oxidation air purification device. <CIT> describes a method for air conditioning an aircraft and an air conditioning unit therefore. <CIT> describes a photocatalytic module for an automobile air conditioner. <CIT> describes an air purifier using ultraviolet rays.

An ultraviolet light surface protection system for a duct is disclosed herein and defined in claim <NUM>.

The coating system may comprise a photoactivated metal oxide. The photoactivated metal oxide may comprise at least one of titanium dioxide, zinc oxide or titanium dioxide doped with nitrogen, sulfur or iron. The germicidal ultraviolet light may have a wavelength between about <NUM> and about <NUM>. The coating may comprise a photocatalytic antimicrobial coating.

An air management system of a vehicle having a conditioned area is disclosed herein. The air management system may comprise: a duct having an interior surface defining a flow path for delivering air to the conditioned area; a sterilization system associated with the duct, the sterilization system including a light source operable to emit a germicidal ultraviolet light into the flow path defined by the duct to sterilize the air to be provided to the conditioned area; and a surface protection system according to claim <NUM> for the interior surface of the duct, the surface protection system configured to be ultraviolet resistive, reflective, and anti-microbial.

In various embodiments, the coating may be in the form of a surface film. In various embodiments, the coating may comprise more than one surface film, with each surface film comprising of at least one of an ultraviolet resistance layer, a reflectivity layer, an anti-microbial layer, and a hydrophobicity layer. The germicidal ultraviolet light may have a wavelength between about <NUM> and about <NUM>. The air within the duct may have a first flow rate at a first portion of the duct and a second flow rate at a second portion of the duct, the second flow rate being slower than the first flow rate, the light source being positioned to emit the germicidal ultraviolet light within the second portion of the duct. The surface protection system may be integral to the duct.

An unclaimed method of manufacturing a composite duct for an air management system is disclosed herein. The method may comprise: forming a pre-impregnated material comprising a resin and at least one of a carbon fiber and a glass fiber; laying up the pre-impregnated material into a female mold assembly; disposing one or more surfacing film(s) on an interior surface of the pre-impregnated material; assembling the female mold assembly; vacuum bagging the female mold assembly with a form fitting vacuum bag; and vacuuming and autoclaving the female mold assembly.

The form fitting vacuum bag may include a complimentary shape to the interior surface to provide a smooth surface finish. In various embodiments, the surfacing film may include a photoactivated catalyst, a metal reflective to ultraviolet light, a quaternary ammonium compound or a resin resistive to degradation by ultraviolet light. The surfacing film may be configured to be ultraviolet resistive, reflective, and anti-microbial. The method may further comprise heating the duct post-cure in a freestanding position.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and their best mode. The detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.

With reference now to <FIG>, a schematic of an example of an air management system <NUM> to control the air of a vehicle, such as an aircraft <NUM> is illustrated. The aircraft <NUM> includes a pressurized area or cabin <NUM> that the air management system <NUM> controls. The cabin <NUM> may be configured to house people, cargo, and the like therein. The air management system <NUM> provides conditioned air to, and removes used or contaminated air from, the cabin <NUM>. The air management system <NUM> includes an environmental control system <NUM> having at least one air conditioning unit or pack <NUM>, and a cabin air recirculation sub-system <NUM>. While the air management system <NUM> is illustrated and described herein with reference to an aircraft <NUM>, it should be understood that the systems and techniques discussed herein may be used for a variety of air management systems <NUM>. For example, the cabin <NUM> may be replaced with any closed volume to be conditioned. As such, systems described herein may be used with ship air management systems, such as submarines and cruise liners for example, personnel carrier air management systems, bus, trolley, train, or subway air management systems, or any other air management system that requires a continual supply of conditioned air.

As shown in the <FIG>, a medium, such as air for example, is provided from one or more sources <NUM> to the air management system <NUM>. Examples of suitable sources <NUM> include but are not limited to an engine of the aircraft <NUM> and an auxiliary power unit of the aircraft <NUM>. The medium output from these sources <NUM> is provided to the one or more air conditioning units <NUM> of the environmental control system <NUM>. Within these air conditioning units <NUM>, the medium is conditioned. This conditioning includes altering one or more of a pressure, temperature, humidity, or flow rate of the medium based on an operating condition of the aircraft. The medium output or discharged from the one or more air conditioning units <NUM> of the environmental control system <NUM> may be used maintain a target range of pressures, temperatures, and/or humidity within the cabin <NUM>.

In an embodiment, the mixed medium is delivered to the cabin <NUM> from the air mixing unit <NUM> via an air distribution system <NUM> including one or more conduits <NUM>. As shown, the mixed medium may be delivered to the cabin <NUM> and cockpit via a ventilation system arranged near a ceiling of the cabin <NUM>. In various embodiments, the mixed medium typically circulates from the top of the cabin <NUM> toward the floor and is distributed to a plurality of individual vents <NUM> of the ventilation system spaced laterally between the front and rear of the cabin <NUM>. It should be understood that the air management system <NUM> illustrated and described herein is intended as an example only, and that any suitable air management system is within the scope of the disclosure.

With reference now to <FIG>, an example of a portion of the cabin air recirculation sub-system within the air management system <NUM> is shown in more detail. In the illustrated, non-limiting embodiment, a portion of the duct <NUM> of the cabin air recirculation sub-system <NUM> fluidly connects one or more inlets <NUM> (see <FIG>) of the cabin <NUM> to the air mixing unit <NUM>. Mounted within the duct is a filter <NUM> configured to remove bacteria, viruses and particulate matter from the cabin recirculation air provided from the inlets <NUM> in the cabin <NUM> as it flows through the filter <NUM>. Although the filter <NUM> is shown as being arranged adjacent a downstream end of the duct, such as directly upstream from an interface between the duct and the air mixing unit, a filter arranged at any location within the duct is contemplated herein. Further, although the filter <NUM> is illustrated as having a circular configuration in <FIG>, and a rectangular configuration in <FIG>, it should be understood that a filter <NUM> having any configuration is within the scope of the disclosure. In various embodiments, the filter <NUM> is a high-efficiency particulate air (HEPA) type filter. However, any suitable filter, or combination of multiple filters is within the scope of the disclosure. Further, in an embodiment, the duct <NUM> includes a recirculation fan <NUM> to establish an overpressure that is used to drive the flow of the recirculating cabin air through the filter <NUM> and to the air mixing unit <NUM>. However, embodiments of a portion of a cabin air recirculation sub-system <NUM> that do not include a fan such that air flow through the duct <NUM> is driven by another source or by pressure for example, are also contemplated herein.

With reference now to <FIG>, in an embodiment, the air management system <NUM> additionally includes a sterilization system <NUM> for sterilizing at least a portion of the air therein. In addition to the removal of particulate matter, the sterilization described herein additionally includes killing or rendering harmless bacteria or airborne viruses within the air management system <NUM> and/or an air flow there through. Because dehumidified air is more readily sterilized, the air is dehumidified before passing through (upstream from) the sterilization system <NUM> and is then re-humidified downstream of the sterilization system <NUM>, such as in the air mixing unit <NUM> for example.

As shown, in various embodiments, the sterilization system <NUM> is used to sterilize a portion of the air provided to the cabin <NUM>, such as the cabin recirculation air discharged from inlets <NUM> of the cabin <NUM> and provided to the air mixing unit <NUM> and/or a portion of one or more ducts <NUM> extending between the cabin inlets <NUM> and the air mixing unit <NUM>. Further, it should be understood that although a duct <NUM> of the cabin air recirculation sub-system <NUM> is illustrated and described herein with respect to the sterilization system <NUM>, any portion of the air management system <NUM>, and specifically any portion or duct that is used to move cabin discharge air or cabin recirculation air through the air management system <NUM>, including but not limited to the air mixing unit <NUM> and the conduits <NUM> of the air distribution system <NUM> for example, may be adapted for use with a sterilization system <NUM> as described herein.

The sterilization system <NUM> includes at least one light source <NUM> capable of emitting a light having a wavelength suitable to perform germicidal irradiation. In an embodiment, the light source <NUM> is operable to emit a germicidal ultraviolet light, such as having a wavelength between about <NUM> and about <NUM> nanometers, also known as "UV-C. " It should be understood that ultraviolet light having another wavelength, such as between <NUM> and <NUM>, and more specifically between <NUM> and <NUM>, or other types of light may also be suitable for use in sterilization applications. Additionally, a light source <NUM> having any configuration, such as an individual bulb, a light strip having a plurality of bulbs or light emitting diodes, or another type of emitter, is within the scope of the disclosure. In embodiments of the sterilization system <NUM> including a plurality of the light source <NUM>, a configuration of the light sources may be substantially identical or may vary based on a position of the light source <NUM> relative to the air management system.

The use of germicidal ultraviolet light, and specifically UV-C light, typically employs exposure for only a matter of seconds to kill all or substantially all virus or bacteria present. However, the length of exposure may vary in response to one or more parameters, such as the wavelength of the light, the intensity or strength of the light, the volume flow rate of air, and the humidity of the air, for example. In various embodiments, the one or more light sources <NUM> and an intensity of each light source <NUM> is determined based on at least one of the volume flow rates and the humidity of the air. Because exposure for only a limited period of time is needed for sterilization, the one or more light sources <NUM> may be disposed at one or more areas along the flow path defined by the duct <NUM>.

In various embodiments, the one or more light sources <NUM> are located at an area of the flow path where the flow of air provided from the cabin inlets <NUM> is slowest. For example, the flow rate of the cabin recirculation air through the portion of the duct <NUM> including the filter <NUM> is reduced relative to the flow rate of the air at an upstream portion of the duct <NUM> to maximize the efficacy of the filter <NUM>. Accordingly, in various embodiments, one or more light sources <NUM> are mounted such that the light emitted therefrom projects over at least a portion, and in some embodiments, over substantially the entire surface <NUM> of the filter <NUM>. As a result, any viruses or bacteria present on the filter <NUM>, such as trapped in the filter material itself, are killed or neutralized. In such embodiments, the one or more light sources <NUM> may be integrated into the filter <NUM> (<FIG>) and/or may be mounted to a portion of the duct <NUM>, such as directly adjacent the filter <NUM> (<FIG>), or alternatively, at a location axially offset from the filter <NUM> (<FIG>) such that the light emitted from the light sources <NUM> overlaps the surface the filter <NUM>.

In various embodiments, the sterilization system <NUM> may additionally include one or more light sources <NUM> arranged at a location where the flow rate of the cabin circulation air flow A is faster than at the filter <NUM>. As shown, one or more light sources <NUM> may be arranged within the air management system <NUM> to emit germicidal ultraviolet light over a portion of the flow path defined by the duct <NUM>, upstream from the filter <NUM>, as shown in <FIG> and <FIG>. Although the figures show a sterilization system <NUM> including a plurality of light sources <NUM> operable to illuminate substantially the entire length of the duct <NUM> extending between an upstream end thereof <NUM> and the filter <NUM>, embodiments where only a portion of the duct <NUM> is illuminated are also contemplated herein. In various embodiments including multiple light sources <NUM>, each of the plurality of light sources <NUM> may be positioned such that the light emitted therefrom overlaps with the light emitted from an adjacent light source <NUM>. As shown, the light sources may be mounted within the same plane, such as adjacent the same side of the duct <NUM>, or in various embodiments, at different sides of the duct <NUM>, such as opposite sides (<FIG>) or adjacent sides (<FIG>) for example. As a result, the region of the duct <NUM> illuminated by the light sources <NUM> will be free from shadows or non-illuminated areas where bacteria or viruses may accumulate.

By mounting one or more light sources <NUM> capable of emitting a germicidal ultraviolet light along the flow path of the cabin recirculation air, the light sources <NUM> may be used to continuously disinfect the airflow and/or a portion of a duct <NUM>, without exposing aircraft occupants to any harmful effects from exposure to a high intensity ultra-violet light. Further, the sterilization system could continuously operate when the vehicle is both airborne and grounded without the need for any chemical means of rendering airborne viruses and bacteria harmless. Additionally, the one or more ultra-violet light sources <NUM> are small, use minimal power, and do not require high power, heat, or chemicals to kill viruses and bacteria.

The duct <NUM> comprises a composite material. A "composite material," as described herein may comprise any composite material, such as carbon fiber, fiber-reinforced polymer (e.g., fiber glass), para-aramid fiber, aramid fiber, fiber reinforced epoxy, and/or carbon fiber-reinforced bismaleimide (BMI). In various embodiments, the duct <NUM> comprises fiber reinforced epoxy or BMI. In various embodiments, utilization of UV light, as disclosed herein, may degrade a composite material, specifically those that contain high degrees of aromaticity. As such, referring now to <FIG>, a surface protection system <NUM> for a duct <NUM> is illustrated, in accordance with various embodiments. In various embodiments, the interior surface <NUM> of the duct <NUM> within the region illuminated by the one or more light sources <NUM> (from <FIG>) may have a coating system <NUM>.

In various embodiments, the coating system <NUM> may be configured for UV resistance, reflectivity, anti-microbial, and/or hydrophobicity. For example, with respect to UV resistance in accordance with various embodiments, the coating system <NUM> may comprise an anti-UV polymer stabilizer, such as benzotriazoles and hydroxyphenyl triazines, oxanilides, and/or benzophenones. With respect to reflectivity, in accordance with various embodiments, the coating system <NUM> may include a reflected or mirrored coating, such as one or more of aluminum, gold, chrome, nickel, titanium, copper, silver, copper oxide, titanium dioxide, zinc oxide, or another suitable shiny material or polished surface. With respect to anti-microbial in accordance with various embodiments, the coating system <NUM> may comprise a photocatalytic antimicrobial coating, such as a titanium dioxide based coating, a NiO/SrBi2O4 based coating, a zinc oxide based coating, or the like. With respect to hydrophobicity, the coating system <NUM> may comprise manganese an oxide polystyrene composite based coating, a zinc oxide polystyrene composite based coating, a precipitated calcium carbonate based coating, a carbon nanotube based coating, a silica sol-gel coating, a fluorinated silane coating, and/or a fluoropolymer coating. In various embodiments, the coating system <NUM> may be multi-functional. For example, a quaternary ammonium compound, such as hexadecyltrimethylammonium ('cetrimide'), chlorhexidine, and a benzalkonium chloride (number of carbon atoms in the alkyl chain (n) = <NUM> - <NUM>), may provide both hydrophobicity and anti-microbial functionality.

The titanium dioxide based coating is a doped titanium dioxide based coating. The dopants in the titanium dioxide coating comprise at least one of iron, sulfur, or nitrogen. A reflectivity layer may comprise a metal, wherein the metal may comprise of aluminum to improve the reflectivity to ultraviolet light. The reflectivity layer comprises aluminum having one or more dielectric layer films to enhance the reflectivity. In various embodiments, each dielectric film layer may comprise of at least one of a polycarbonate or an oxide. In various embodiments, the oxide layer may comprise of silicon dioxide.

Further, in accordance with various embodiments, coating system <NUM> may be applied via any suitable method, such as via a spray, dip, wipe, vapor deposition, plating, or other known method. In an embodiment, the coating material is applied via vapor deposition, such as via atomic layer deposition for example. Application of a coating material via atomic layer deposition permits non-line-of-sight coating because a molecular layer of various germicidal chemical compounds may be formed anywhere the vapor makes contact.

In various embodiments, the coating system <NUM> may be a multi-layered coating system. For example, the coating system <NUM> may comprise a UV resistance layer, a reflectivity layer, an anti-microbial layer, and a hydrophobicity layer. In various embodiments, a single coating may include all or most of the functionality as outlined above. In various embodiments, the coating system <NUM>, as described herein, may be configured to protect the interior surface <NUM> of the duct <NUM> from degradation due to exposure to UV light, from microbes, and/or provide more efficient airflow through the system. In various embodiments, the UV resistance, reflectivity, anti-microbial, and/or hydrophobicity may be achieved through additive in the composite, in accordance with various embodiments.

For example, referring now to <FIG>, an unclaimed method of manufacturing a duct having a surface protection system is illustrated. The method <NUM> may comprise forming pre-impregnated material (step <NUM>). The pre-impregnated material may be formed by impregnating a carbon or a glass fiber with a resin.

The resin may include an epoxy or the like. The method <NUM> may further comprise laying up the pre-impregnated material into a mold (step <NUM>). The mold may comprise a female mold or a male mold. In various embodiments, the mold may include a complimentary shape to a duct. The duct may be in accordance with duct <NUM> from <FIG>.

The method <NUM> may further comprise disposing a surfacing film on an interior surface of the pre-impregnated material (step <NUM>). The surfacing film may be configured in accordance with the coating system <NUM> from <FIG>. For example, the surfacing film may be configured for UV resistance, reflectivity, anti-microbial, and/or hydrophobicity. For example, photoactivated metal oxide, such as a titanium dioxide based coating, may be injected into the surfacing film prior to disposing the surfacing film on the interior surface. The method <NUM> may further comprise assembling the mold (step <NUM>).

The method <NUM> may further comprise vacuum bagging the mold assembly (step <NUM>). Vacuum bagging the mold assembly may include utilizing a form fitting vacuum bag. A form fitting vacuum bag, as described herein is a vacuum bag foam, or the like, having a complimentary shape to an interior surface of the duct. In this regard, the vacuum bagging process may provide a smoother surface finish relative to typical vacuum bagging applications. In this regard, a smoother surface may provide a more reflective surface. A smooth surface as described herein includes a surface roughness between <NUM> and <NUM>µin. (<NUM> and <NUM>) or between <NUM> and <NUM>µin. (<NUM> and <NUM>). Reflective, as described herein refers to a glossmeter between <NUM> GU and <NUM> GU or between <NUM> GU and <NUM> GU. A more reflective surface may more effectively reflect the UV light and/or more effectively disinfect the airflow and/or a portion of a duct <NUM> while the sterilization system is in use.

The method <NUM> further comprises placing the mold assembly under vacuum and an autoclave pressure at a temperature up to <NUM> °F (<NUM>) for about six hours (step <NUM>). Step <NUM> may result in a cured composite duct with a coating system, as illustrated in <FIG>. After the autoclave process, the method <NUM> further comprises removing the cured composite duct from the mold assembly and heating the duct in a freestanding position at a temperature up to <NUM> °F (<NUM>) for about six hours.

The method <NUM> may produce a duct assembly having a surface protection system in accordance with <FIG>. In this regard, the duct assembly may be configured to survive exposure to UV sterilization with little to no degradation. The duct assembly may include anti-microbial and reflective functionality to enhance the disinfecting capability of the UV light and the exposure of the UV light of the air management system. The duct assembly may be laid up using resin pressure molding in a closed mold.

However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosures.

The scope of the disclosures is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more.

In the detailed description herein, references to "one embodiment", "an embodiment", "an example embodiment", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiment.

Claim 1:
An ultraviolet light surface protection system for a duct (<NUM>), comprising:
an interior surface for the duct (<NUM>), the duct comprising any composite material;
a light source (<NUM>) operable to emit a germicidal ultraviolet light into a flow path of the duct defined by the interior surface of the duct to sterilize an air to be provided to a conditioned area; and
a coating system (<NUM>) disposed on the interior surface, the coating system (<NUM>) configured to be ultraviolet resistive, reflective, and anti-microbial, the coating system comprising a doped titanium dioxide coating, the dopants in the doped titanium coating comprising at least one of iron, sulfur, and nitrogen;
a reflectivity layer comprising aluminum having at least one dielectric layer film and a quaternary ammonium compound, the coating system further comprising a quaternary ammonium compound providing both hydrophobicity and anti-microbial functionality. .