Patent Publication Number: US-2023150684-A1

Title: Additively manufactured canister for a nitrogen generation system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a division of U.S. application Ser. No. 16/422,368 filed May 24, 2019, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Exemplary embodiments pertain to the art of nitrogen generation systems and more specifically to an additively manufactured air separation module for a nitrogen generation system of an aircraft. 
     A flammability reduction system (FRS), also known as a nitrogen generation system (NGS) for aircrafts comprises components that route a portion of bleed air from an engine, separate inert air from the bleed air, and deliver the inert air to the fuel tank. The inert gas displaces other existing gases in the fuel tank, creating a layer of inert gas on top of the liquid fuel. This layer reduces the flammability of the fuel tank. 
     One component of the NGS includes an air separation module (ASM). The ASM separates the flammable gas (oxygen) from the inert gas (nitrogen), and passes the inert gas through an outlet port to the fuel tank. Typical embodiments of currently operated NGSs utilize one or more straight canisters that contain synthetic flexible membrane fibers that separate the oxygen from the nitrogen in the engine bleed air. 
     BRIEF DESCRIPTION 
     Disclosed is a method of manufacturing an air separation module (ASM) for a nitrogen generation system (NGS), comprising: determining an at least partially nonlinear shape between opposing ends of a canister, the canister being configured to fit within an installation envelope for the ASM in the NGS and configured to have installed therein an air separating membrane; and additively manufacturing the canister. 
     In addition to one or more of the above disclose features and the method further comprises installing the air separating membrane in the canister. 
     In addition to one or more of the above disclose features or as an alternate, installing the air separating membrane in the canister includes drawing the air separating membrane from one end of the canister to the other end of the canister, and securing the air separating membrane to opposing ends of the canister. 
     In addition to one or more of the above disclose features, the method includes determining a diameter of the canister for installing therein the air separating membrane; and wherein additively manufacturing the canister includes additively manufacturing the canister to provide the determined diameter. 
     In addition to one or more of the above disclose features, or as an alternate, additively manufacturing the canister includes utilizing a selective laser sintering (SLS) process. 
     In addition to one or more of the above disclose features, or as an alternate, the SLS process includes utilizing thermoplastic to form the canister. 
     In addition to one or more of the above disclose features, or as an alternate, the shape between opposing ends is an arcuate shape. 
     In addition to one or more of the above disclose features, or as an alternate, the arcuate shape is one of S-shape, banana shape, or helix shape. 
     Further disclosed is a method of configuring an air separation module (ASM) of a nitrogen generation system (NGS), comprising: determining an at least partially nonlinear shape between opposing ends of a canister of the ASM, the canister being configured to fit within an installation envelope for the ASM in the NGS and configured have installed therein an air separating membrane, the canister being manufactured by a method including one or more of the above disclosed features. 
     Further disclosed is an aircraft system comprising: a fuel tank; an air separation module (ASM) of a nitrogen generation system (NGS), the ASM in fluid communication with the fuel tank and disposed within an installation envelope in the aircraft; and the ASM comprising a canister having an at least partially nonlinear shape between opposing ends. 
     In addition to one or more of the above disclosed features, or as an alternate, the at least partially nonlinear shape between opposing ends is one of S-shape, banana shape, or helix shape. 
     In addition to one or more of the above disclosed features, or as an alternate, the canister includes therein an air separating membrane. 
     In addition to one or more of the above disclosed features, or as an alternate, the at least partially nonlinear shape between opposing ends is also noncircular. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG.  1    is a schematic illustration of an aircraft that can incorporate various embodiments of the present disclosure; 
         FIG.  2    is a schematic illustration of a bay section of the aircraft of  FIG.  1   ; 
         FIG.  3    is a diagram of a nitrogen generation systems (NGS) for an aircraft in which the disclosed embodiments may be utilized; 
         FIG.  4    illustrates air separation module and fibers in a canister for the air separation module; 
         FIGS.  5   a - 5   d    illustrate different shaped canisters for an ASM according to a disclosed embodiment; and 
         FIG.  6    illustrates a method of configuring an ASM according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     As shown in  FIGS.  1 - 2   , an aircraft includes an aircraft body  101 , which can include one or more bays  103  beneath a center wing box. The bay  103  can contain and/or support one or more components of the aircraft  101 . For example, in some configurations, the aircraft can include environmental control systems and/or fuel inerting systems within the bay  103 . As shown in  FIG.  2   , the bay  103  includes bay doors  105  that enable installation and access to one or more components (e.g., environmental control systems, fuel inerting systems, etc.) installed within or on the aircraft. During operation of environmental control systems and/or fuel inerting systems of the aircraft, air that is external to the aircraft can flow into one or more ram air inlets  107 . The outside air (i.e., ram air) may then be directed to various system components (e.g., environmental conditioning system (ECS) heat exchangers) within the aircraft. Some air may be exhausted through one or more ram air exhaust outlets  109 . 
     Also shown in  FIG.  1   , the aircraft includes one or more engines  111 . The engines  111  are typically mounted on the wings  112  of the aircraft and are connected to fuel tanks (not shown) in the wings. The engines and/or fuel tanks may be located at other locations depending on the specific aircraft configuration. In some aircraft configurations, air can be bled from the engines  111  and supplied to environmental control systems and/or fuel inerting systems, as will be appreciated by those of skill in the art. 
     Although shown and described above and below with respect to an aircraft, embodiments of the present disclosure are applicable to any type of vehicle. For example, aircraft, military vehicles, heavy machinery vehicles, sea craft, ships, submarines, etc., may benefit from implementation of embodiments of the present disclosure. For example, aircraft and other vehicles having fire suppression systems, emergency power systems, and other systems that may electrochemical systems as described herein may include the redundant systems described herein. As such, the present disclosure is not limited to application to aircraft, but rather aircraft are illustrated and described as example and explanatory embodiments for implementation of embodiments of the present disclosure. 
     Turning to  FIG.  3   , a nitrogen generation system (NGS)  130  is illustrated. The NGS  130  may include a pressurized air source  132 , which may bleed air  135  from the engine  111 . The bleed air  135  may be conditioned using for example a heat exchanger  136  using a cooling medium such as ram air  137 . The cooled air is filtered using a filter  138 . An air separation module (ASM)  140  of the NGS  130  receives the conditioned and pressurized air  135  and separates the pressurized air into two gasses, one containing mostly oxygen  144  which is discarded and inert air (nitrogen-enriched air)  146 . The inert air  146  may be pressure-regulated after leaving the ASM  140  and directed to the fuel tank. At the fuel tank, the inert air replaces other gases, including flammable gasses, which may be within the fuel tank. 
     Turning to  FIG.  4    the ASM  140  comprises a canister generally referenced as  160 . The canister  160  is formed of aluminum. The canister  160  has a linear shape and may be referred to herein as linear canister  160 . The linear canister  160  may have a diameter D and length L defined by a distance between opposing ends  162 ,  164 . In one embodiment the linear canister  160  is cylindrical. The linear canister  160  contains a flexible membrane  170  ( FIG.  4   ). The membrane  170  separates oxygen molecules and nitrogen molecules from each other in air. In one embodiment, the membrane  170  comprises a bundle of fibrous material. Opposing ends  180   a ,  180   b  of the membrane  170 , are secured to the canister  160  by a fastener such as an adhesive or other mechanical fastener. A size of a canister  160  may depend on a size of a fuel tank being treated by the ASM  140 . A larger fuel tank requires a greater amount of inert air. The greater amount of inert air requires a greater amount of membrane  170 , and thus a larger canister  160 , or multiple canisters. 
     Available space for installing a canister  160  may be limited within an installation envelope in the NGS  130 . The installation envelope may form a complex geometry based on aircraft structures and components, which may be driven by the airframer. Turning now to  FIGS.  5   a - 5   d   , in view of the size constraints of installation envelopes typically found on aircraft disclosed herein are different configurations for a canister generally referred to as  200  that include at least partially nonlinear shape between opposing ends  202 ,  204 . Such canister  200  may be generally referred to herein as a shaped canister  200 . This can be accomplished, in one embodiment, by making the shaped canister  200  using additive manufacturing processes, or 3D printing, or the like. 
     For example, one configuration for the shaped canister  200   a  may be an S-shape ( FIG.  5   a   ). Another configuration for the shaped canister  200   b  may be a banana shape ( FIG.  5   b   ). A further configuration for the shaped canister  200   c - 200   d  may be spiral or helix shape ( FIGS.  5   c - 5   d   ) (also referred to herein as the helical shaped canister  200   c - 200   d ). 
     Restrictions in the ASM  140  installation volume can reduce the size of a linear canister  160 , thus reducing the capability of the NGS  130 . The configurations of the shaped canister  200  in  FIGS.  5   a - 5   d    provide similar to or greater internal surface area than the linear canister  160  (FIG. 4 ), contoured to better fit the installation envelope that the linear canister  160  cannot. Thus, dependent on the aircraft installation envelope, such configurations may increase an amount of membrane  170  that may be installed in a shaped canister  200  as opposed to a prior art linear canister  160 . This is because, for example, within a same installation envelope, a rectified length (e.g., a total length along a nonlinear shape) of the shaped canister  200  of  FIGS.  5   a - 5   d    may greater than the length L of the linear canister  160 . 
     For example, a rectified length of the helical shaped canister  200   c - 200   d  ( FIGS.  5   c - 5   d   ) is the square root of the sum of the squared height H and the squared circumference, and wherein the circumference is the diameter of the helix DH times Pie (3.1417). If the height H of the helical shaped canister  200   c - 200   d  is equal to the length L of the linear canister  160  ( FIG.  4   ), then the rectified length of the helical shaped canister  200   c - 200   d  is necessarily greater than the length L of the linear canister  160 . If H of the helical shaped canister  200   c - 200   d  is the same as L of the linear canister  160 , the surface area available for the membrane  170  in the helical shaped canister  200   c - 200   d  is greater than the surface area for the linear canister  160 . This determination is based in part on the DH for the helical shaped canister  200   c - 200   d  being non-zero and the diameter D of the helical shaped canister  200   c - 200   d  and the linear canister  160  being the same. 
     It is to be appreciated that modifying the diameter D of the shaped canister  200  in  FIGS.  5   a - 5   d    provides a further ability to increase an amount of air separating membrane  170  that may be installed in the shaped canister  200 . Varying both the shape and the diameter of the shaped canister  200  to increase an amount of air separating membrane  170  within the shaped canister  200  is within the scope of the disclosed embodiments. 
     Complex shapes of the shaped canister  200  may be formed by connected canister sections which may be either linear or nonlinear. For example, the S-shape for the shaped canister  200   a  ( FIG.  5   a   ) may be obtained with two sections  200   a   1 ,  200   a   2  meeting at a junction  200   a   3 . In this configuration, the two sections  200   a   1 ,  200   a   2  have opposing curve shapes to thereby form the S-shape. The banana shape for shaped canister  200   b  ( FIG.  5   b   ) may be obtained with two sections  200   b   1 ,  200   b   2  meeting at a junction  200   b   3 . In this configuration one section  200   a   1  is linear and the other section  200   b   2  is curved to thereby form the banana shape. As illustrated in  FIG.  5   c   , the helix-shape for the shaped canister  200   c  may be formed from a single section having a constant arc-curve extending between opposing ends  202 ,  204 . In one embodiment, as illustrated in  FIG.  5   d   , the helix-shape for the shaped canister  200   d  may be formed from a plurality of sections  200   d   1 ,  200   d   2  connected at a plurality of seams, for example  200   d   3 , to form the integrated canister  200   d.    
     For each configuration of the ASM  140 , the shaped canister  200  includes the membrane  170 . The membrane  170  may be installed by drawing the membrane  170  from one end  202  of the shaped canister  200  toward the other end  204  of the shaped canister  200 . Then the membrane  170  is secured to the opposing ends of the shaped canister  200 . 
     In an embodiment an additive process of selective laser sintering (SLS) is utilized to form the shaped canister  200 . One non-limiting material for being utilized in the SLS process is a thermoplastic such as poly-ether-ketone-ketone (PEKK). Using the SLS process with a thermoplastic as a sintering material results in a relatively high strength, low weight structure for the shaped canister  200 . The shaped canister  200  obtained with the SLS process may have a relatively complex shape ( FIGS.  5   a - 5   c   ) and be relatively light compared with an aluminum linear canister  160  ( FIG.  4   ), and thus suitable for an ASM  140 . In addition to new-build installations, an ASM  140  comprising such shaped canister  200  may be retrofitted into an NRS  130  that is part of an existing aircraft  100 . 
     Turning to  FIG.  6   , a method is disclosed of configuring the ASM  140 . The method includes block  500  of determining an at least partially nonlinear shape between opposing ends  202 ,  204  of the shaped canister  200 . The purpose of this determination is to configure the shaped canister  200  to fit within the installation envelope of the ASM  140  and to store therein an air separating membrane  170 . In one embodiment the shape between opposing ends  202 ,  204  is one of S-shape, banana shape, or helix shape. In one embodiment block  500  further includes determining a diameter of the shaped canister  200  for the ASM  140 . Block  510  includes additively manufacturing the shaped canister  200 . In one embodiment block  510  includes utilizing a selective laser sintering (SLS) process to fabricate the shaped canister  200 . In one embodiment block  510  includes utilizing a thermoplastic to form the shaped canister  200 . Block  520  includes installing the air separating membrane  170  in the shaped canister  200 . In one embodiment block  520  includes drawing the air separating membrane  170  from one end  202  of the shaped canister  200  to the other end  204  of the shaped canister  200 , and securing the air separating membrane  170  to the opposing ends  202 ,  204  of the shaped canister  200 . At block  530 , the shaped canister  200  is installed in the installation envelope for the NGS  130 . 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. 
     While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.