Patent Description:
Air in an aircraft cabin can contain bacteria exerted from passengers and the environment. Current systems are designed to recycle air from the aircraft cabin; however, bacteria are reemitted into the cabin, whereby passengers can continue to be exposed. Traditional metallic heat exchangers and layup composite structures that makeup the ductwork of an aircraft air conditioning system cannot be readily modified to eliminate buildup and reentry of bacteria <CIT> describes a coated heat exchanger. <CIT> describes an air conditioning system for an automobile. <CIT> describes a method for manufacturing a heat exchanging coil fin unit.

A flow path component is provided and defined in claim <NUM>.

Preferred embodiments of the flow path component are identified in the dependent claims <NUM>-<NUM>.

An air conditioning system for an aircraft is defined in claim <NUM>.

A method of manufacturing a flow path component is provided and defined in claim <NUM>.

Preferred embodiments of the method of claim <NUM> are identified in the dependent claims <NUM>-<NUM>.

Technical effects of embodiments of the present disclosure include formation of antimicrobial surfaces on flow path components of an air conditioning system of an aircraft.

<FIG> is a schematic representation of airflow progression <NUM> through an air conditioning system <NUM> of an aircraft. It is understood that the air conditioning system <NUM> is utilized for exemplary purposes and the embodiments disclosed herein may be applied to other systems other than an air conditioning system <NUM> of an aircraft. The airflow progression <NUM> is a representation of bleed air <NUM> as it passes from a compressor stage <NUM>, to an air conditioning system <NUM> (which includes a heat exchanger <NUM>, moisture extraction component <NUM>, and air cycle machine <NUM>), and onto a cabin <NUM>. <FIG> is a simplified schematic representation of the system, highlighting locations of one or more flow path components in the airflow progression <NUM>, which can include ductwork and other components within the airflow progression <NUM>. All elements upstream of the heat exchanger <NUM> and downstream of the moisture extraction component <NUM> are not depicted. It should be appreciated that, although particular systems in <FIG> are separately defined in the schematic block diagram, each or any of the systems may be otherwise combined or separated via hardware and/or software. For example, the moisture extraction component <NUM> may be a part of at least one of the compressor stage <NUM>, the heat exchanger <NUM>, the air cycle machine <NUM>, and the cabin <NUM>. A recirculation path <NUM> can extract air from the cabin <NUM> to use in combination with the bleed air <NUM> or in place of bleed air <NUM>, for example, when the bleed air <NUM> is unavailable or insufficient.

The air conditioning system <NUM> can be a sub-system of an aircraft engine that conditions bleed air <NUM> so that bleed air <NUM> can be re-used to perform an additional function within the aircraft. The bleed air <NUM> is taken from a compressor stage <NUM> of the aircraft engine. In other non-limiting embodiment, the bleed air <NUM> can be compressed air taken from an ambient environment. The compressor stage <NUM> can be an intermediate or high pressure stage within the aircraft engine. The heat exchanger <NUM> can be a condenser for condensing moisture from air into droplets. The moisture extraction component <NUM> can be an elongated tube of solid material with hydrophobic and/or hydrophilic surfaces for extracting moisture from air. The air cycle machine <NUM> is a component of the air conditioning system <NUM> for controlling the temperature and pressure of air exiting from the air cycle machine <NUM> and into cabin <NUM>. The cabin <NUM> is a compartment of the aircraft for housing passengers and/or equipment.

The compressor stage <NUM> can be fluidly connected to the heat exchanger <NUM> via fluid lines or conduits in the aircraft. The heat exchanger <NUM> can be fluidly connected to the moisture extraction component <NUM>. The moisture extraction component <NUM> is fluidly connected to the air cycle machine <NUM>, and the air cycle machine <NUM> is fluidly connected to the cabin <NUM>.

During operation of the aircraft engine, bleed air <NUM> is drawn from the compressor stage <NUM> and into the heat exchanger <NUM> of the air conditioning system <NUM>. The heat exchanger <NUM> can cool and condense moisture in the bleed air <NUM> and/or from the recirculation path <NUM> from vapor into moisture droplets. In some non-limiting embodiments, the heat exchanger <NUM> can increase or decrease the temperature of air received at the heat exchanger <NUM>. The air with the condensed moisture droplets can then be transported toward the air cycle machine <NUM>. The air cycle machine <NUM> further conditions the air by altering the temperature and the pressure of the air to a level appropriate for the passengers in the cabin <NUM>. A more detailed example of an aircraft air conditioning system and/or an environment control system can be found in <CIT>.

<FIG> depicts an example of an additive manufacturing system <NUM> configured to perform an additive manufacturing process to form a flow path component <NUM>, such as a heat exchanger <NUM>, ducting, or other component of the air conditioning system <NUM> of <FIG>. The additive manufacturing system <NUM> is depicted schematically and can support any type of additive manufacturing processes known in the art. For example, the additive manufacturing system <NUM> can be configured to support stereo-lithography using photo-polymerization or a fused deposition modelling process using extrusion-type printing to melt raw materials and form a plurality of layers. Other examples can include selective laser sintering, thermoforming, and known additive manufacturing processes.

In the example of <FIG>, an application apparatus <NUM> can control the formation of a plurality of layers of the flow path component <NUM> within a manufacturing chamber <NUM>. The application apparatus <NUM> can be selected corresponding to the type of additive manufacturing process employed. For example, the application apparatus <NUM> may include a light emitting device or a laser and lens system for stereo-lithography or can include an extrusion head and nozzles for fused deposition modelling. A plurality of additive manufacturing materials <NUM> can be selectively formed into the flow path component <NUM> using the application apparatus <NUM> and other supporting subsystems, such as temperature and position controls. The additive manufacturing materials <NUM> can include a plurality of materials 106A, 106B,. , 106N used at different manufacturing stages. For example, a base material can be used to form a primary structure of the flow path component <NUM> as part of a <NUM>-D printing process, for instance, of a non-metallic composite material. Other additive manufacturing materials <NUM> can include surface coatings, adhesive materials, antimicrobial nanoparticles, and other such materials. The additive manufacturing materials <NUM> can include any combination of liquid photopolymer, thermoplastic feedstock, powder, paste, and/or other known material types.

Where ultraviolet curing or other curing methods are used as part of the additive manufacturing process, the flow path component <NUM> may have a tacky surface to enable deposition and partial embedding of antimicrobial nanoparticles to surfaces of the flow path component <NUM> prior to a final curing stage. If the resulting flow surfaces of the flow path component <NUM> are not sufficiently tacky to support direct embedding of the antimicrobial nanoparticles to surfaces of the flow path component <NUM>, an adhesive material can be applied to support embedding the antimicrobial nanoparticles in one or more flow surfaces of the flow path component <NUM>. Examples of adhesive materials can include polyurethane, epoxy sealant binder, acrylic, photo-cured resin, and other such materials known in the art.

To support the application of antimicrobial nanoparticles to surfaces of the flow path component <NUM> during the manufacturing process, a blower <NUM> can be operably coupled to the manufacturing chamber <NUM> to create an air vortex, such that release of the antimicrobial nanoparticles from the additive manufacturing materials <NUM> can be dust-blown onto surfaces of the flow path component <NUM> prior to final curing of the flow path component <NUM> by a curing device <NUM>. The dust-blowing process is free of binders or solvents as opposed to typical spray coating applications. The dust-blowing process can result in coating over <NUM>% of unmasked surfaces with the antimicrobial nanoparticles, while exposing surface area of the antimicrobial nanoparticles on flow surfaces of the flow path component <NUM>. The curing device <NUM> can be a heating element operable to thermally cure the flow path component <NUM>. Alternatively, the curing device <NUM> can be a light source, such as an ultraviolet light source, operable to perform photo-assist curing of the antimicrobial nanoparticles. In embodiments, prior to final curing, the flow path component <NUM> may have a tacky or sticky surface that traps the antimicrobial nanoparticles when dust blown using the blower <NUM> within the manufacturing chamber <NUM>. Depositing the antimicrobial nanoparticles prior to final curing results in embedding the antimicrobial nanoparticles at or substantially near the surface of the flow path component <NUM>, such that the antimicrobial nanoparticles are at least partially exposed external to the surface. In some embodiments, the antimicrobial nanoparticles can be, for example, silver and/or silver oxide nanoparticles operable to disrupt cell functions of bacteria. In addition to the bactericidal properties of the antimicrobial nanoparticles, the dust-blowing process followed by a final curing results in forming a nanoscale texturing of the antimicrobial nanoparticles on the flow path component <NUM>, where the texturing also kills or otherwise reduces bacterial adhesion.

A controller <NUM> can interface with and control multiple elements of the additive manufacturing system <NUM>, such as positions, flow rates, pressures, temperatures, and the like. Process steps, such as deposition and/or curing, can occur within the manufacturing chamber <NUM> or may be distributed between multiple instances of the manufacturing chamber <NUM>. As an example, the controller <NUM> can control a deposition recipe and/or provide deposition/light control of the additive manufacturing materials <NUM> through the application apparatus <NUM>, control airflow out of the blower <NUM>, and control the curing device <NUM>. In an embodiment, the controller <NUM> includes a memory system <NUM> to store instructions that are executed by a processing system <NUM> of the controller <NUM>. The executable instructions may be stored or organized in any manner and at any level of abstraction, such as in connection with a controlling and/or monitoring operation of the additive manufacturing system <NUM>. The processing system <NUM> can include one or more processors that can be any type of central processing unit (CPU), including a microprocessor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like. Also, in embodiments, the memory system <NUM> may include random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic, or any other computer readable medium onto which is stored data and control algorithms in a non-transitory form.

<FIG> is a partial cross-sectional view of the flow path component <NUM> of <FIG>, according to an embodiment of the present disclosure. Although the example of <FIG> depicts a simple tube-like structure for purposes of explanation, it will be understood that the flow path component <NUM> can include complex features, such as a plurality of flow channels when embodied as the heat exchanger <NUM> of <FIG>.

The flow path component <NUM> can include a flow path component body <NUM>, an inlet <NUM>, an outlet <NUM>, an outer surface <NUM>, an inner surface <NUM>, and a main flow channel <NUM>. The inner surface <NUM> of the flow path component <NUM> defines the main flow channel <NUM>, which fluidly connects the inlet <NUM> to the outlet <NUM>. A plurality of antimicrobial nanoparticles <NUM> are embedded in the inner surface <NUM> of the flow path component body <NUM> by the additive manufacturing system <NUM> of <FIG>. In some embodiments, the flow path component body <NUM> is composed of a non-metallic material, and the antimicrobial nanoparticles <NUM> can include one or more of: silver and silver oxide nanoparticles. In some embodiments, a coating can be applied to form a hydrophobic surface on the inner surface <NUM> prior to embedding the antimicrobial nanoparticles <NUM> in the inner surface <NUM> of the flow path component body <NUM>, where the inner surface is an example of a flow surface <NUM>. The hydrophobic surface can be composed of a hydrophobic compound configured to repel moisture away from the inner surface <NUM> of the flow path component body <NUM>. As an air flow <NUM> propagates through the main low channel <NUM>, bacteria contacting the antimicrobial nanoparticles <NUM> in the flow surface <NUM> can be killed due to the antimicrobial properties of the antimicrobial nanoparticles <NUM> and/or nanoscale texturing of the antimicrobial nanoparticles <NUM> on the flow surface <NUM>.

<FIG> depicts a cross section of a portion of the flow path component <NUM> according to an embodiment where the inner surface <NUM> and the outer surface <NUM> of the flow path component body <NUM> are both a flow surface <NUM> embedded with antimicrobial nanoparticles <NUM>. Other variations are contemplated beyond annular or tubular structures. For example, as depicted in <FIG>, the flow surface <NUM> on the flow path component body <NUM> can be a substantially planar surface embedded with antimicrobial nanoparticles <NUM> configured to kill bacteria entrained in air flow <NUM>. Planar configurations may be portions of a larger apparatus, such as a plate-fin embodiment of the heat exchanger <NUM> of <FIG>.

<FIG> depicts a simplified schematic view of a portion of nanoscale texturing <NUM> of the flow surface <NUM> of flow path component <NUM>, according to an embodiment. The nanoscale texturing <NUM> includes pointed/sharp substantially conical structures <NUM> formed in polymer cure material that may perforate microbe cells. Externally exposed surface area of the antimicrobial nanoparticles <NUM> can also kill microorganisms in combination with the conical structures <NUM>. The conical structures <NUM> is formed responsive to the dust-blown impact of the antimicrobial nanoparticles <NUM> on the flow surface <NUM> (e.g., where still tacky or an adhesive material is used) prior to final curing in combination with controlling parameters of the final curing process, for instance, by the controller <NUM> of <FIG>.

Referring now to <FIG>, with continued reference to <FIG>. <FIG> shows a method <NUM> of manufacturing a flow path component. At block <NUM>, an additive manufacturing process is performed using the additive manufacturing system <NUM> to form a flow path component <NUM> including a flow path component body <NUM> having a flow surface <NUM>.

At block <NUM>, a plurality of antimicrobial nanoparticles <NUM> is embedded in the flow surface <NUM> such that the antimicrobial nanoparticles <NUM> are at least partially exposed external to the flow surface <NUM>. Embedding the antimicrobial nanoparticles <NUM> in the flow surface <NUM> of the flow path component body <NUM> includes applying the antimicrobial nanoparticles <NUM> to the flow surface <NUM> of the flow path component body <NUM> using the application apparatus <NUM> of the additive manufacturing system <NUM> and thermally or photo-assist curing the flow path component <NUM> using the curing device <NUM> after the antimicrobial nanoparticles <NUM> are applied from the additive manufacturing materials <NUM>. Applying the antimicrobial nanoparticles <NUM> to the flow surface <NUM> of the flow path component body <NUM> includes distributing the antimicrobial nanoparticles <NUM> on the flow surface <NUM> using a dust-blowing process with the blower <NUM>. An adhesive material can be applied on the flow surface <NUM> of the flow path component body <NUM> prior to circulating the antimicrobial nanoparticles <NUM> using the dust-blowing process, for example, to further enhance adhesion prior to final curing. Applying the antimicrobial nanoparticles <NUM> to the flow surface <NUM> of the flow path component body <NUM> can include applying a hydrophobic surface containing the antimicrobial nanoparticles <NUM> to the flow surface <NUM> of the flow path component body <NUM>.

Claim 1:
A flow path component (<NUM>), comprising:
a flow path component body (<NUM>) comprising a flow surface (<NUM>), the flow surface configured to be exposed to an air flow within a flow channel between an inlet and an outlet of the flow path component; and
a plurality of antimicrobial nanoparticles (<NUM>) embedded in the flow surface (<NUM>) and at least partially exposed external to the flow surface (<NUM>) within the flow channel forming a nanoscale texturing on the flow surface, the nanoscale texturing comprising a plurality of pointed/sharp substantially conical structures (<NUM>) formed in polymer cure material, configured to perforate microbe cells between the antimicrobial nanoparticles embedded within the flow surface.