Patent Publication Number: US-11384885-B2

Title: Flexible double walled hose connection

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 15/946,502, entitled: “Flexible Double Walled Hose Connection”, filed on 2018 Apr. 5, which is incorporated herein by reference in its entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     This disclosure generally relates to a flexible fluid conduit. More specifically, this disclosure relates to a flexible double walled hose connection which utilizes inner and outer swaging. 
     BACKGROUND 
     Aircraft include fluid systems for transporting fluids throughout the vehicle. Many of the fluids, such as fuel, are hazardous. Thus, the fluid systems need to be very reliable. 
     In many portions of the aircraft, rigid conduits can be utilized in the fluid system. However, in some areas of the vehicle, for load dissipation and to simplify the installation process, more flexible conduits are desirable. In view of the above, flexible conduits, which can be used in aircraft and other fluid transport applications, are described. 
     SUMMARY 
     One aspect of the disclosure can be related to a fluid system. The fluid system can include a plurality of conduits configured to transport a fluid. In one embodiment, the fluid system can be used on an aircraft to transport a fluid, such as fuel. A first conduit in the fluid system can include: 1) a first ferrule having an outer portion and an inner portion, 2) a second ferrule having an outer portion an inner portion, 3) a flexible inner hose and 4) a flexible outer wall. 
     The flexible inner hose can be configured to receive the fluid. The flexible inner hose can have: 1) a first end disposed between a first surface on the inner portion of the first ferrule and a first inner swage ring where the first inner swage ring is swaged to secure the first end of the flexible inner hose to the first ferrule and 2) a second end disposed between a first surface on the inner portion of the second ferrule and a second inner swage ring where the second inner swage ring is swaged to secure the second end of the flexible inner hose to the second ferrule. 
     The flexible outer wall can surround the flexible inner hose, the first inner swage ring and the second inner swage ring. The flexible outer wall can provide a barrier if the flexible inner hose leaks. The flexible outer wall can have: 1) a first end disposed between a second surface on the outer portion of the first ferrule and a first outer swage ring where the first outer swage ring is swaged to secure the first end of the flexible outer wall to the first ferrule and 2) a second end disposed between a second surface on the outer portion of the second ferrule and a second outer swage ring where the second outer swage ring is swaged to secure the second end of the flexible outer wall to the second ferrule. 
     In one embodiment, the outer portion and the inner portion of the first ferrule can be integrally formed. In another embodiment, the outer portion and the inner portion of the first ferrule can be formed as separate pieces. When the outer portion and the inner portion are separately formed, a plurality of fasteners can be used to secure the outer portion to the inner portion. 
     In a particular embodiment, the flexible outer wall can be formed from a first flexible outer hose, a second flexible outer hose and a support sleeve. A first end of the first flexible outer hose can form the first end of the flexible outer wall, which is swaged to the first ferrule. A second end of the second flexible outer hose can form the second end of the flexible outer wall, which is swaged to the second ferrule. 
     Further, a second end of the first flexible outer hose can be disposed between a first surface on the support sleeve and a third outer swage ring, The third outer swage ring can be swaged to secure the second end of the first flexible outer hose to the support sleeve. A first end of the second flexible outer hose can be disposed between a second surface on the support sleeve and a fourth outer swage ring. The fourth outer swage ring can be swaged to secure the first end of the second flexible outer hose to the support sleeve. 
     In yet other embodiments, the fluid system can include one or more fluid reservoirs disposed between the flexible inner hose and the flexible outer wall. The fluid reservoirs can each be configured to receive the fluid when the flexible inner hose leaks. The first ferrule and the second ferrule can each include a plurality of flow channels in fluid communication with the one or more fluid reservoirs. The plurality of flow channels can allow fluid in the one or more fluid reservoirs to flow through the first ferrule and the second ferrule. 
     In further embodiments, a cross section of the flexible outer wall can be circular. In this instance, a diameter of the flexible outer wall can be between one and ten inches. A length of the first conduit can be between ten and thirty inches. In addition, the first ferrule or the second ferrule can include a flange. 
     In another embodiment, the fluid system can further include a bonding agent. The bonding agent can be disposed between one or more of 1) the flexible inner hose and the first surface on the inner portion of the first ferrule, 2) the flexible inner hose and the first inner swage ring and 3) combinations thereof. In a particular embodiment, the fluid system can be used on an aircraft. 
     Another aspect of the disclosure can be related to a ferrule. The ferrule can include an inner portion, an outer portion and a plurality of fluid channels. The inner portion can have a first surface configured to receive a first end of a flexible inner hose and a first inner swage ring. The first inner swage ring can be swaged to couple the first end of the flexible inner hose to the first surface. 
     The outer portion can have a second surface configured to receive a first end of a flexible outer hose and a first outer swage ring. The flexible outer hose can surround a portion of the flexible inner hose. The first outer swage ring can be swaged to couple the first end of the flexible outer hose to the second surface. The plurality of fluid channels can be configured to allow fluid to travel between the inner portion and the outer portion. 
     In particular embodiments, the inner portion and the outer portion can be integrally formed. In another embodiment, the inner portion and the outer portion can be separately formed. Thus, a plurality of fasteners can be configured to couple the inner portion to the outer portion. Further, the inner portion can include a flange for coupling the ferrule to a fluid conduit. The plurality of fluid channels can be configured to transport a leakage of the fluid resulting from a break in the flexible inner hose through the ferrule. 
     Another aspect of the disclosure can be related to a method of assembling a fluid conduit. The method can be generally characterized as 1) inserting a first end of a flexible inner hose over a first surface of an inner portion of a first ferrule; 2) swaging a first inner swage ring to secure the first end of the flexible inner hose to the first surface of the inner portion of the first ferrule where the first end of the flexible inner hose can be disposed between the first inner swage ring and the first surface of the inner portion of the first ferrule; 3) inserting a first end of a flexible outer wall over the flexible inner hose and over a second surface on an outer portion of a first ferrule; 4) swaging a first outer swage ring to secure the first end of the flexible outer wall to the second surface on the outer portion of the first ferrule where the first end of the flexible outer wall can be disposed between the first outer swage ring and the second surface on the outer portion of the first ferrule; 5) inserting a second end of the flexible inner hose over a first surface of an inner portion of a second ferrule; 6) swaging a second inner swage ring to secure the second end of the flexible inner hose to the first surface of the inner portion of the second ferrule where the second end of the flexible inner hose can be disposed between the second inner swage ring and the first surface of the inner portion of the second ferrule; 7) inserting a second end of the flexible outer wall over the flexible inner hose and over a second surface on an outer portion of a second ferrule; and 8) swaging a second outer swage ring to secure the second end of the flexible outer wall to the second surface on the outer portion of the second ferrule where the second end of the flexible outer wall can be disposed between the second outer swage ring and the second surface on the outer portion of the second ferrule. 
     In particular embodiments, the inner portion of the first ferrule and the outer portion of the first ferrule can be integrally formed. Further, the inner portion of the second ferrule and the outer portion of the second ferrule can be integrally formed. Alternatively, the inner portion of the first ferrule and the outer portion of the first ferrule can be separately formed and fastened together. Also, the inner portion of the second ferrule and the outer portion of the second ferrule can be separately formed and fastened together. 
     In one embodiment, the flexible outer wall can be formed from a flexible hose. In another embodiment, the flexible outer wall can include a first flexible outer hose, a second flexible outer hose and a support sleeve. The support sleeve can be formed from a rigid material. 
     In more detail, when a first end of the first flexible outer hose forms the first end of the flexible outer wall, the method can further include swaging a third outer swage ring to secure a second end of the first flexible outer hose to the support sleeve where the second end of the first flexible outer hose can be disposed between the support sleeve and the third outer swage ring. Further, when a second end of the second outer flexible hose forms the second end of the flexible outer wall, the method can further include swaging a fourth outer swage ring to secure a first end of the second flexible outer hose to the support sleeve where the first end of the second flexible outer hose can be disposed between the support sleeve and the fourth outer swage ring. 
     Another aspect of the disclosure can be related to a method of using a fluid system. The method can be generally characterized as including transporting a fluid through a fluid system having a first conduit. The first conduit can include 1) a first ferrule having an outer portion and an inner portion; 2) a second ferrule having an outer portion and an inner portion, 3) a flexible inner hose and 4) a flexible outer wall. 
     The flexible inner hose can be configured to receive the fluid and can have: 1) a first end disposed between a first surface on the inner portion of the first ferrule and a first inner swage ring where the first inner swage ring is swaged to secure the first end of the flexible inner hose to the first ferrule and 2) a second end disposed between a first surface on the inner portion of the second ferrule and a second inner swage ring where the second inner swage ring can be swaged to secure the second end of the flexible inner hose to the second ferrule. 
     The flexible outer wall can surround the flexible inner hose, the first inner swage ring and the second inner swage ring. The flexible outer wall can have 1) a first end disposed between a second surface on the outer portion of the first ferrule and a first outer swage ring where the first outer swage ring can be swaged to secure the first end of the flexible outer wall to the first ferrule and 2) a second end can be disposed between a second surface on the outer portion of the second ferrule and a second outer swage ring where the second outer swage ring can be swaged to secure the second end of the flexible outer wall to the second ferrule. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Having thus described examples of the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein like reference characters designate the same or similar parts throughout the several views, and wherein: 
         FIG. 1A  is a perspective view illustrating an airplane, according to one aspect of the present disclosure. 
         FIG. 1B  is a top view illustrating a jet aircraft and fuel tank locations, according to one aspect of the present disclosure. 
         FIG. 2  is a top view of a flexible doubled wall hose connection according to one aspect of the present disclosure. 
         FIG. 3  is a first cross sectional view of the flexible doubled wall hose connection of  FIG. 2 , according to aspects of the present disclosure. 
         FIG. 4A  is a second cross sectional view of the flexible doubled wall hose connection of  FIG. 2 , according to one aspect of the present disclosure. 
         FIG. 4B  is a cross sectional view of a ferrule, according to one aspect of the present disclosure. 
         FIGS. 5A and 5B  are a block diagram of a method of assembling a doubled wall hose connection of  FIG. 2  according to one aspect of the present disclosure. 
         FIG. 6  is a top view of a flexible doubled wall hose connection according to another aspect of the present disclosure. 
         FIG. 7  is a first cross sectional view of the flexible doubled wall hose connection of  FIG. 6 , according to aspects of the present disclosure. 
         FIGS. 8A and 8B  are second cross sectional views of the flexible doubled wall hose connection of  FIG. 6 , according to one aspect of the present disclosure. 
         FIG. 9  is a block diagram of a method of assembling a doubled wall hose connection of  FIG. 6  according to one aspect of the present disclosure. 
         FIG. 10  is a block diagram of an aircraft production and service methodology that can utilize the fluid conduits described herein, according to one aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous specific details are set forth in order to provide a thorough understanding of the presented concepts. The presented concepts may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail so as to not unnecessarily obscure the described concepts. While some concepts will be described in conjunction with the specific examples, it will be understood that these examples are not intended to be limiting. 
     Reference herein to “one example” or “one aspect” means that one or more feature, structure, or characteristic described in connection with the example or aspect is included in at least one implementation. The phrase “one example” or “one aspect” in various places in the specification may or may not be referring to the same example or aspect. 
     Introduction 
     A flexible conduit for transporting fluids in a fluid system, such a fluid system on an aircraft, and methods of assembling the flexible conduit described. The flexible conduit can include a flexible inner hose for transporting a fluid. The flexible inner hose can be surrounded by a flexible outer wall to form a flexible doubled wall hose connection. The flexible outer wall can be configured to contain any leakage of fluid from the flexible inner hose. The flexible inner hose and the flexible outer wall can be coupled on each end to ferrules. Swage rings can be swaged to secure the flexible inner hose and the flexible outer wall to the ferrules. 
     In more detail, with respect to  FIG. 1 , a jet aircraft and fuel tank locations are discussed. The fuel tanks can be part of a fluid system which utilizes the flexible fluid conduits described herein, such as the flexible doubled wall hose connection. With respect to  FIG. 2 , a flexible doubled wall hose connection is described. With respect to  FIGS. 3 and 4A , a first and a second cross sectional view of the flexible doubled wall hose connection of  FIG. 2  are described. With respect to  FIG. 4B , a cross section of a ferrule is described. With respect to  FIGS. 5A and 5B , a method of assembling a doubled wall hose connection of  FIG. 2  is discussed. 
     With respect to  FIG. 6 , a second design of a flexible doubled wall hose connection is discussed. With respect to  FIGS. 7, 8A and 8B , first, second and third cross sectional views of the flexible double wall hose connection of  FIG. 6  are described. With respect to  FIG. 9 , a method of assembling a doubled wall hose connection of  FIG. 6  is discussed. Finally, with respect to  FIG. 10 , an aircraft production and service methodology that can utilize the fluid conduits described herein is described. 
     Aircraft 
       FIG. 1A  is a perspective view illustrating an airplane  2  and its associated aerodynamic high-lift device surfaces. On the wings  25 , slats  5  are used near the leading edge of each wing. Near the trailing edge, spoilers  4 , inboard (IB) flap  6 , flaperon  8  and outboard (OB) flap  10 , and an aileron  12  are provided on each wing. The high-lift device surfaces, such as the inboard flap  6 , can be configured to articulate in some manner, relative to the wings  25 . 
     The empennage  27  is provided with a vertical stabilizer  13 , rudder  16  and rudder tab  18 . The horizontal stabilizer  14  is provided with an elevator  20 . The rudder  16  and rudder tab  18  can be configured to move relative to the vertical stabilizer and the elevator can be configured to move relative to the horizontal stabilizer. 
     In various embodiments, the airplane  2  can have an in-flight refueling system. For example, the airplane  2  can be configured to receive fuel in flight from another airplane. In another example, the airplane  2  can be configured as a tanker to deliver fuel to another airplane in-flight, such as the jet  30 , described below with respect to  FIG. 1B . 
     The airplane  2  can include a fluid system used to store and transport fuel as part of the in-flight refueling system. The fluid system can include a plurality of tanks for storing the fuel and a plurality of conduits for transporting the fluid to the tanks and between tanks. The plurality of conduits for transporting the fluid can travel among pressurized and non-pressurized zones on the airplane  2 . The pressurized zones can have a high oxygen concentration. In the non-pressurized zones, the oxygen concentration can be much lower. 
     In the pressurized zones, because of the high oxygen concentrations, fuel leaks in fuel lines can pose a very serious fire hazard. Thus, it may be desirable to provide fluid conduits with extra safety precautions, such as double walls for containing fuel leaks. Examples of fluid conduits with double walls, which can provide an extra layer of safety for fuel containment, are described below with respect to  FIGS. 2-9 . 
       FIG. 1B  is a top view illustrating a jet  30  (F-15E) and fuel tank locations. In one embodiment, the jet can be configured have an in-flight refueling system. For example, the jet  30  can be configured to receive fuel from airplane  2  in  FIG. 1A  when the airplane  2  is configured as a tanker. 
     The jet  30  includes a cockpit  36 , a left wing  32 , a right wing  34  and one or more fluid systems for transporting a fluid. The fluid can be in a liquid or a gas state. As examples, a fluid system can be used to store and transport fuel on the jet. As another example, a fluid system can be used to transport hydraulic fluid on the jet. In yet another example, the fluid system can be used to store and transport oxygen on the jet used by the pilot. 
     The fluid system used to store and transport the fuel is shown in more detail. The fluid system can include a plurality of tanks for storing the fuel and a plurality of conduits for transporting the fluid to the tanks and between tanks. For example, a main tank  38 , a left wing tank  40 , a right wing tank  42 , a right engine feed tank  44 , a left engine feed tank  46  and auxiliary tank  48 , which store the fuel, are shown. 
     The jet  30  includes an in-flight refueling port  45 , which can open in flight to allow for in-flight refueling. The in-flight refueling port  45  is coupled to a conduit, which is the refueling pipe  47 . The refueling pipe transports fuel to the main tank  38 . Other conduits (not shown) in the fluid system can transport fuel between the tanks, such as between main tank  38  and the left wing tank  40  or the right wing tank  42 . As another example, conduits can transport fuel from the main tank  38  to the right engine feed tank  44  or the left engine feed tank. 
     In some instances, a conduit in the fluid system can be formed from a rigid material. In other instances, it may be desirable to utilize a flexible conduit to link different portions of the fluid system. For example, a flexible conduit may be desirable to utilize in a fluid system in areas that experience high structural vibration or in areas where structural interfaces occur, such as between the wing and the body of the jet. In general, the flexible conduit can be useful for load dissipation and for simplifying the installation of the fluid system. 
     Embodiments of flexible conduits that can be utilized in a fluid system are described below in the following section with respect to  FIGS. 2-9 . The flexible conduits can be utilized in a fluid system on an aircraft, such as the airplane or the jet, described above with respect to  FIGS. 1A and 1B . In addition, the flexible conduits can be utilized in ground based fluid systems, such as but not limited to ground based fueling systems. 
     Flexible Double Walled Hose Connection 
     Next, with respect to  FIGS. 2-9 , flexible conduits which can be utilized in a fluid system are described. The flexible conduits can be formed by swaging flexible hoses to ferrules. In particular embodiments, the flexible conduits can be doubled walled to form flexible double walled hose connections. In more detail, with respect to  FIGS. 2-5B , first embodiments of a flexible double walled hose connection and methods of assembling the first embodiments are described. With respect to  FIGS. 6-8B , second embodiments of a flexible double walled hose connection and methods of assembling the second embodiments are described. 
       FIG. 2  is a top view of a flexible doubled wall hose (FDWH) connection  50 , which is a first conduit that can be used in a fluid system. The FDWH connection  50  includes a first ferrule  52  and a second ferrule  54 . A flexible outer wall is formed between the first ferrule and the second ferrule. A first end of the flexible outer wall can be secured to the first ferrule  52  using the first outer swage ring  58   a  and the second end of the flexible outer wall can be secured to the second ferrule  54  via the fourth outer swage ring  58   d.    
     As shown in  FIG. 2 , the FDWH component  50  can use swage rings, such as  58   a ,  58   b ,  58   c  and  58   d , to secure components. Swaging is a forging process in which the dimensions of an item can be altered using dies into which the item is forced. Swaging can be a cold or hot working process. Rotary swaging involves using two or more dies to hammer a round component, such as the swage rings, into a smaller diameter. 
     The sloped lines on the swage rings, such as line  55  on the first outer swage ring  58   a , can represent the reduction in diameter of the swage ring due to swaging. The linear shape is shown for the purposes of illustration only. In general, after swaging, the outer diameter of the swage rings can be decreased in some areas and increased in other areas, where the increases and decreases of the outer diameter don&#39;t follow a linear profile. 
     In a particular embodiment, the flexible outer wall can be formed using a first flexible outer hose  60 , a second flexible outer hose  61  and a support sleeve  62 . A first end of the flexible outer hose  60 , which forms the first end of the flexible outer wall, can be swaged to the first ferrule using the first outer swage ring  58   a . A second end of the first flexible outer hose  60  can be swaged to the support sleeve  62  using the second outer swage ring  58   b . In particular embodiments, the support sleeve  62  can be formed from a rigid material, such as a metal (e.g., aluminum or steel). 
     A first end of the second flexible outer hose  61  can be swaged to the support sleeve  62  using the third outer swage ring  58   c . A second end of the second flexible outer hose  61 , which forms the second end of the flexible outer wall, can be swaged to the second ferrule  54 . The fourth outer swage ring  58   d  can be swaged to secure the second end of the second flexible hose  61  to the second ferrule. 
     The notches  64  for limit rings on the support sleeve  62  can be used when the second outer swage ring  58   b  and the third outer swage ring are swaged. The notches  64  can receive limit rings (e.g., see  112   a  and  112   b  in  FIG. 3 ). The limit ring adjacent to the second outer swage ring  58   b  can prevent the second outer swage ring  58   b  from moving to the left over the support sleeve  62  when it is swaged. The limit ring adjacent to the third outer swage ring  58   c  can prevent the third outer swage ring  58   c  from moving to the left over the support sleeve  62  when it is swaged. 
     In particular embodiments, the first ferrule  52  and/or the second ferrule  54  can include a flange. For example, the second ferrule  54  includes a flange  56 . The flange  56  can be used to secure the FDWH connection  50  to another conduit in the fluid system. For example, the flange  56  can include a plurality of apertures which allow fasteners to be inserted to secure the flange  56  to another conduit, such as a conduit with a complementary flange and apertures. 
     As described above, the FDWH connection  50  is double walled. To illustrate an internal structure of the FDWH connection  50 , cross sections along lines  65  and  67  are described as follows with respect to  FIGS. 3 and 4 . In particular,  FIG. 3  shows an internal structure of the ferrules and the internal hoses. Whereas,  FIG. 4A  shows an internal structure of the first ferrule  52 . 
       FIG. 3  is a first cross sectional view  100  along line  65  of the FDWH connection  50  of  FIG. 2 . The first ferrule  52  (see  FIG. 2 ) can include an outer portion  52   a  and inner portion  52   b . In particular embodiments, the outer portion  52   a  and the inner portion  52   b  can be integrally formed. In another embodiment, the outer portion  52   a  and the inner portion  52   b  can be separately formed and fastened together (e.g., see  FIGS. 7, 8A ). The first ferrule  52  can be formed from a metal, such as steel or aluminum. 
     Similarly, the second ferrule  54  (see  FIG. 2 ) can have an outer portion  54   a  and inner portion  54   b . In particular embodiments, the outer portion  54   a  and the inner portion  54   b  can be integrally formed. In another embodiment, the outer portion  54   a  and the inner portion  54   b  can be separately formed and fastened together. The second ferrule  54  can be formed from a metal, such as steel or aluminum. 
     A plurality of swage rings are shown in the  FIG. 3 . The plurality of swage rings include a first inner swage ring  102   a , a second inner swage ring  102   b , a first outer swage ring  58   a , a second outer swage ring  58   b , a third outer swage ring  58   c  and a fourth outer swage ring  58   d . In  FIG. 3 , the plurality of swage rings are shown after swaging has been applied as indicated by the sloped outer diameter. As described above, the sloped shape is for the purposes of illustration only and is not meant to be limiting. 
     Prior to swaging, the shape of the swage rings, such as the outer diameter, can be different than after swaging. For example, the outer diameter of the swage rings can be a constant diameter prior to swaging. After swaging, the outer diameter of the swage rings can be reduced in some areas and increased in other areas. In addition, the inner diameter of the swage rings can be reduced after swaging. The reduction in the inner diameters in the swage rings can secure 1) the flexible inner hose  110  to the first ferrule  52  and the second ferrule  54 , 2) the first flexible outer hose  60  to the first ferrule  52  and the support sleeve  62  and 3) the second flexible outer hose  61  to the second ferrule  54  and the support sleeve  62 . The swage rings can be formed from a metal, such as steel or aluminum. 
     The inner portion  52   b  of the first ferrule  52  can have a first surface  52   c  configured to receive a first end  110   a  of a flexible inner hose  110 . Prior to swaging, a first inner swage ring  102   a  can be positioned over the first surface  52   c  and the first end  110   a  of the flexible inner hose  110  such that the first end  110   a  of the flexible inner hose  110  is disposed between the first inner swage ring  102   a  and the first surface  52   c . Then, the first inner swage ring  102   a  can be swaged to secure the first end  110   a  of the flexible inner hose  110  to the inner portion  52   b  of the first ferrule  52 . 
     The inner portion  54   b  of the second ferrule  54  can have a first surface  54   c  configured to receive a second end  110   b  of a flexible inner hose  110 . Prior to swaging, a second inner swage ring  102   b  can be positioned over the first surface  54   c  and the second end  110   b  of the flexible inner hose  110  such that the second end  110   b  of the flexible inner hose  110  is disposed between the second inner swage ring  102   b  and the first surface  54   c . Then, the second inner swage ring  102   b  can be swaged to secure the second end  110   b  of the flexible inner hose  110  to the inner portion  54   b  of the second ferrule  54 . 
     As described above with respect to  FIG. 2 , the first flexible outer hose  60 , the support sleeve  62 , the second flexible outer hose  61  can form a flexible outer wall. In this example, the support sleeve  62  can be rigid. Thus, the flexible outer wall can include flexible portions and rigid portions. In another embodiment, the flexible outer wall can be formed entirely from a flexible material, such as a continuous flexible outer hose (e.g., see  FIG. 6 ). 
     The outer portion  52   a  of the first ferrule  52  can have a second surface  52   d  configured to receive a first end  60   a  of the first flexible outer hose  60 . Prior to swaging, the first outer swage ring  58   a  can be positioned over the second surface  52   d  and the first end  60   a  of the first flexible outer hose  60  such that the first end  60   a  of the first flexible outer hose  60  is disposed between the first outer swage ring  58   a  and the second surface  52   d . Then, the first outer swage ring  58   a  can be swaged to secure the first end  60   a  of the first flexible outer hose  60  to the outer portion  52   a  of the first ferrule  52 . 
     A second end  60   b  of the first flexible outer hose  60  can be inserted over the support sleeve  62  in the region to the right of the first limit ring  112   a . Prior to swaging, the second outer swage ring  58   b  can be positioned over the second end  60   b  of the first flexible outer hose  60  and the support sleeve  62  such that the second end  60   b  of the first flexible outer hose  60  is disposed between the second outer swage ring  58   b  and the support sleeve  62 . Then, the second outer swage ring  58   b  can be swaged to secure the second end  60   b  of the first flexible outer hose  60  to the support sleeve  62 . 
     A first end  61   a  of the second flexible outer hose  61  can be inserted over the support sleeve  62  in the region to the left of the second limit ring  112   b . Prior to swaging, the third outer swage ring  58   c  can be positioned over the first end  61   a  of the second flexible outer hose  61  and the support sleeve  62  such that the first end  61   a  of the second flexible outer hose  61  is disposed between the third outer swage ring  58   c  and the support sleeve  62 . Then, the third outer swage ring  58   c  can be swaged to secure the first end  61   a  of the second flexible outer hose  61  to the support sleeve  62 . 
     The outer portion  54   a  of the second ferrule  54  can have a second surface  54   d  configured to receive a second end  61   b  of the second flexible outer hose  61 . Prior to swaging, the fourth outer swage ring  58   d  can be positioned over the second surface  54   d  and the second end  61   b  of the second flexible outer hose  61  such that the second end  61   b  of the second flexible outer hose  61  is disposed between the fourth outer swage ring  58   d  and the second surface  54   d . Then, the fourth outer swage ring  58   d  can be swaged to secure the second end  61   b  of the second flexible outer hose  61  to the outer portion  54   a  of the second ferrule  54 . 
     In particular embodiments, prior to swaging, a bonding agent or a sealing agent can be applied between 1) an inner surface of a flexible hose and an adjacent surface, 2) between an inner surface of a swage ring and an outer surface of the flexible hose or 3) combinations thereof. For example, prior to swaging, a bonding agent or a sealing agent can be applied between an inner surface of the flexible inner hose  110  and the first surface  52   c  on the inner portion  52   b  of the first ferrule. In another example, prior to swaging, a bonding agent or a sealing agent can be applied between an inner surface of the first flexible outer hose  60  and the second surface  52   d  on the outer portion  52   a  of the first ferrule  52 . In yet another example, prior to swaging, a bonding agent or a sealing agent can be applied between an outer surface of the flexible inner hose  110  and an inner surface of the first inner swage ring  102   a . In a further example, prior to swaging, a bonding agent or a sealing agent can be applied between an outer surface of the first flexible outer hose  60  and an inner surface of the first outer swage ring  58   a.    
     After assembling, fluid  115   a , fluid  115   b  and fluid  115   c  can be transported through an interior of the inner portion  52   b  of the first ferrule  52 , an interior of the flexible inner hose  110  and an interior of the inner portion  54   b  of the second ferrule  54 , respectively. The flexible outer wall including the first flexible outer hose  60 , the support sleeve  62  and the second flexible outer hose  61  can surround the flexible inner hose  110 . The flexible outer wall and the flexible inner hose  110  can be offset by a spacing amount in some areas to form fluid reservoirs, such as  106   a  and  106   b . Further, a gap can be provided between the support sleeve  62  and the flexible inner hose  110  to form flow the outer flow channel  105 . Thus, fluid can be transported between the fluid reservoirs  106   a  and  106   b.    
     A fluid reservoir, such as  106   a  and  106   b , can accumulate fluid when the flexible inner hose  110  is transporting fluid and a nearby breakage of the flexible inner hose  110  occurs. The fluid reservoirs can be in fluid communication with flow channels in the ferrules. The flow channels can receive fluid which accumulates in the fluid reservoirs, such as  106   a  and  106   b , and transport the fluid through the ferrules, such as between the inner portion and the outer portion of the ferrule. 
     For example, the first ferrule  52  can include a plurality of flow channels, such as  122   a  and  122   b , between the outer portion  52   a  and the inner portion  52   b , which are in fluid communication with fluid reservoir  106   a . An example of the plurality of flow channels  122  is shown in  FIG. 4A , which is a second cross sectional view  120  of the FDWH connection  50  of  FIG. 2  along line  67 . The plurality of flow channels  122  can be disposed between the outer portion  52   a  and the inner portion  52   b  of the first ferrule  52 . The number and arrangement of the flow channels  122  is provided for the purposes of illustration only and is not meant to be limiting. 
     Returning to  FIG. 3 , fluid which has accumulated in fluid reservoir  106   a  can flow through one or more of the flow channels  122 , such as  122   a  and  122   b , and through the exit  104   a , which can be a ring, between the inner portion  52   b  and the outer portion  52   a . In one embodiment, exit  104   a  can be sealed or covered in some manner, such as with a transparent material. The transparent material can allow fluid which has accumulated near the exit  104   a  to be viewed while still containing the fluid. Thus, a breakage in the flexible inner hose  110  can be detected while still maintaining fluid containment. 
     In one embodiment, a sensor can be provided near the exit  104   a  which can be used to convey an indication that the fluid has traveled through the first ferrule  52 . For example, a sensor can be provided which changes color when it comes into contact with the fluid, such as  115   a  that is transported through the FDWH connection  50 . The sensor can be disposed near exit  104   a . A change in color of the sensor can be used to indicate that a breakage in the flexible inner hose  110  has occurred. 
     Similar to the first ferrule  52 , the second ferrule  54  can include flow channels, such as  124   a  and  124   b , which are in fluid communication with the fluid reservoir  106   b . The flow channels can be disposed between the inner portion  54   b  and the outer portion  54   a  of the second ferrule  54 . Fluid can accumulate in fluid reservoir  106   b , travel through one of the flow channels and exit through exit  104   b . Further, fluid can travel between the fluid reservoir  106   a  and the fluid reservoir  106   b  via the outer flow channel  105 . 
     In another embodiment, the FDWH connection  50  can be used to transport to different fluids simultaneously in a fluid system. For example, as described above, a first fluid can be transported can be transported through an interior of the inner portion  52   b  of the first ferrule  52 , an interior of the flexible inner hose  110  and an interior of the inner portion  54   b  of the second ferrule  54 . A second fluid can be transported between the outer portion  52   a  and inner portion  52   b  of the first ferrule  52 , through fluid reservoir  106   a , through the outer flow channel  105  between the support sleeve  62 , through the fluid reservoir  106   b , and through the flexible inner hose  110  and between the outer portion  54   a  and the inner portion  54   b  of the second ferrule  54 . The first fluid and the second fluid can be transported in a same or a different direction from one another. 
     As shown in  FIG. 4A , a cross section of the first ferrule  52  can be circular. In particular embodiments, the flexible inner hose  110 , the first flexible outer hose  60 , the second flexible outer hose  61 , the support sleeve  62 , the second ferrule  54 , first outer swage ring  58   a , the second outer swage ring  58   b , the third outer swage ring  58   c , the fourth outer swage ring  58   d , the first inner swage ring  102   a  and the second inner swage ring  102   b  can each have a circular cross section. In the case of the swage rings, the diameter can vary across its length. Whereas, the hoses and the support sleeve can have a constant diameter. 
     In particular, a diameter of the flexible outer wall, such as a diameter of the first flexible outer hose  60  or the second flexible outer hose  61 , can be between one and ten inches. A length of a first conduit, such as the FDWH connection  50 , can be between ten and thirty inches. However, larger or smaller diameters or larger or smaller lengths can be used and these examples are provided for the purposes of illustration only. These ranges can also be applied to second design of the FDWH connection  300  described below with respect to  FIGS. 6-9 . 
     In a particular embodiment, the material of the flexible hoses, such as the flexible inner hose  110 , the first flexible outer hose  60  or the first flexible inner hose can be formed from a synthetic rubber. In another embodiment, a clamp between be disposed between the first limit ring  112   a  and the second limit ring  112   b . The clamp can be used to secure the FDWH connection  50  to an adjacent structure, such as an internal structure of an aircraft. 
       FIG. 4B  shows a cross section of the first ferrule  52  along line  65  in  FIG. 2 . The first ferrule  52  can include an inner portion  52   b , an outer portion  52   a  and a plurality of fluid channels, such as  122   a  and  122   b . The inner portion  52   b  can have a first surface  52   c  configured to receive a first end of a flexible inner hose and a first inner swage ring. As described above, the first inner swage ring can be swaged to couple the first end of the flexible inner hose to the first surface. 
     The outer portion  52   a  can have a second surface  52   d  configured to receive a first end of a flexible outer hose and a first outer swage ring. The flexible outer hose can surround a portion of the flexible inner hose. The first outer swage ring can be swaged to couple the first end of the flexible outer hose to the second surface. The plurality of fluid channels, such as  122   a  and  122   b , can be configured to allow fluid to travel between the inner portion  52   b  and the outer portion  52   a.    
     Next, a method  200  of assembling a FDWH connection  50  of  FIG. 2-4  is described with respect to  FIGS. 5A and 5B . In  202 , the first end of the flexible inner hose can be inserted over the first surface on the inner portion of the first ferrule. In  204 , the first inner swage ring can be positioned over the first end of the flexible inner hose such that the first end is disposed between the first inner swage ring and the first surface. Then, the first inner swage ring can be swaged to secure the first end of the flexible inner hose to the first ferrule. 
     In  206 , the first end of the first flexible outer hose can be inserted over the second surface on an outer portion of the first ferrule. In  208 , the first outer swage ring can be positioned over the first end of the first flexible outer hose such that the first end is disposed between the first outer swage ring and the second surface. Then, the first outer swage ring can be swaged to secure the first end of the first flexible outer hose to the first ferrule. 
     In  210 , the support sleeve can be inserted over the flexible inner hose and beneath the second end of first flexible outer hose. In  212 , the second outer swage ring can be positioned over the second end of the first flexible outer hose such that the second end is disposed between the second outer swage ring and the support sleeve. Then, the second outer swage ring can be swaged to secure the second end of the first flexible outer hose to the support sleeve. 
     In  214 , the second flexible outer hose can be inserted over the flexible inner hose and the first end of second flexible outer hose can be inserted over the support sleeve. In  216 , the third outer swage ring can be inserted over the flexible inner hose and the second flexible outer hose. In  218 , the second inner swage ring can be inserted over the flexible inner hose. In  220 , the fourth outer swage ring can be inserted over the flexible inner hose and the second flexible outer hose. 
     In  222 , the second end of the flexible inner hose can be inserted over the first surface on the inner portion of the second ferrule. In  224 , the third outer swage ring, the fourth outer swage ring and the second flexible outer hose can be slid to the right over the support sleeve to generate space to swage the second inner swage ring. In  226 , the second inner swage ring can be positioned over the second end of the flexible inner hose such that the second end of the flexible inner hose is disposed between the second inner swage ring and the first surface on the inner portion of the second ferrule. Then, the second inner swage ring can be swaged to secure the second end of the flexible inner hose to the second ferrule. 
     In  228 , the second end of the second flexible outer hose can be slid over the second surface on the outer portion of second ferrule. In  230 , the third outer swage ring can be positioned over the first end of the second flexible outer hose such that the first end is disposed between the third outer swage ring and the support sleeve. Then, the third outer swage ring can be swaged to secure the first end of the second flexible outer hose to the support sleeve. In  232 , the fourth outer swage ring can be positioned over the second end of the second flexible outer hose such that the second end is disposed between the fourth outer swage ring and the second surface on the outer portion of the second ferrule. Then, the fourth outer swage ring can be swaged to secure the second end of the second flexible outer hose to the second ferrule. 
     Next, with respect to  FIGS. 6-9 , second designs of a flexible double walled hose connection and methods of assembling the designs are described.  FIG. 6  is a top view of a FDWH connection  300 , which is a second conduit that can be used in a fluid system. The FDWH connection  300  includes a first outer ferrule  308 , a first inner ferrule  310 , a second outer ferrule  312  and a second inner ferrule  314 . 
     A flexible outer wall can be formed between the first outer ferrule  308  and the second outer ferrule  312  using the flexible outer hose  306 . A first end of the flexible outer hose  306  can be secured to the first outer ferrule  308  using the first outer swage ring  302  and a second end of the flexible outer wall can be secured to the second outer ferrule via the second outer swage ring  304 . The first outer swage ring  302  and the second outer swage ring  304  are shown in a post-swaged shape. 
     As shown in  FIG. 7 , the first inner ferrule  310  can extend into an interior of the first outer ferrule  308 . Further, the second inner ferrule  314  can extend into an interior of the second outer ferrule  312 . The first inner ferrule  310  and the second inner ferrule  314  can be coupled to a flexible inner hose (not visible). To illustrate the interfaces between 1) the first inner ferrule  310 , the second inner ferrule  314  and the flexible inner hose  322 , 2) the first outer ferrule  308  and the first inner ferrule  310  and 3) the second outer ferrule  312  and the second inner ferrule  314 , the FDWH connection  300  is rendered along cross section line  316  and cross section line  318  in  FIGS. 7 and 8A , respectively.  FIG. 8B  shows an alternate rendering of FDWH connection  300  along cross section line  318 . 
       FIG. 7  is a first cross sectional view  320  of the FDWH connection  300  of  FIG. 6  along cross section line  316 . As described above, the flexible inner hose  322  can be coupled to the first inner ferrule  310  and the second inner ferrule  314 . The flexible inner hose  322  can be surrounded by the flexible outer hose  306 . 
     The first inner ferrule  310  can have a first surface  310   a  configured to receive a first end  322   a  of the flexible inner hose  322 . Prior to swaging, a first inner swage ring  330  can be positioned over the first surface  310   a  and the first end  322   a  of the flexible inner hose  322  such that the first end  322   a  of the flexible inner hose  322  is disposed between the first inner swage ring  330  and the first surface  310   a . Then, the first inner swage ring  330  can be swaged to secure the first end  322   a  of the flexible inner hose  322  to the first inner ferrule  310 . 
     The second inner ferrule  314  can have a first surface  314   a  configured to receive a second end  322   b  of the flexible inner hose  322 . Prior to swaging, a second inner swage ring  332  can be positioned over the first surface  314   a  and the second end  322   b  of the flexible inner hose  322  such that the second end  322   b  of the flexible inner hose  322  is disposed between the second inner swage ring  332  and the first surface  314   a  on the second inner ferrule  314 . Then, the second inner swage ring  332  can be swaged to secure the second end  322   b  of the flexible inner hose  322  to the second inner ferrule  314 . 
     The first outer ferrule  308  can have a first surface  308   a  configured to receive a first end  306   a  of the flexible outer hose  306 . Prior to swaging, a first outer swage ring  302  can be positioned over the first surface  308   a  and the first end  306   a  of the flexible outer hose  306  such that the first end  306   a  of the flexible outer hose  306  is disposed between the first outer swage ring  302  and the first surface  308   a . Then, the first outer swage ring  302  can be swaged to secure the first end  306   a  of the flexible outer hose  306  to the first outer ferrule  308 . 
     The second outer ferrule  312  can have a first surface  312   a  configured to receive a second end  306   b  of the flexible outer hose  306 . Prior to swaging, a second outer swage ring  304  can be positioned over the first surface  312   a  and the second end  306   b  of the flexible outer hose  306  such that the second end  306   b  of the flexible outer hose  306  is disposed between the second outer swage ring  304  and the first surface  312   a . Then, the second outer swage ring  304  can be swaged to secure the second end  306   b  of the flexible outer hose  306  to the second outer ferrule  312 . 
     In one embodiment, the first inner ferrule  310 , the flexible inner hose  322  and the second inner ferrule  314  can be coupled to one another, via the first inner swage ring  330  and the second inner swage ring  332 , to form an inner assembly. The first outer ferrule  308 , the flexible outer hose  306  and the second outer ferrule  312  can be coupled to one another, via the first outer swage ring  302  and the second outer swage ring  304 , to form an outer assembly. Then, the inner assembly can be inserted into the outer assembly and secured together via fasteners, such as fasteners  334   a ,  334   b ,  334   b  and  334   d , to form the FDWH connection  300 . Additional details of the assembly and fastening process are described in more detail below with respect to  FIGS. 8A, 8B and 9 . 
     The inner assembly, including the first inner ferrule  310 , the flexible inner hose  322  and the flexible second inner ferrule  314 , can form an inner flow channel configured to transport a fluid, such as fluid  328   a , fluid  328   b  and fluid  328   c  through the FDHW connection  300 . The outer assembly, including the first outer ferrule  308 , the flexible outer hose  306  and the second outer ferrule  312 , surrounds the inner assembly. Between the inner assembly and the outer assembly, an outer flow channel  324  can be formed. 
     The outer flow channel  324  can capture fluid if any breakages occur in the flexible inner hose  322  while the flexible inner hose is transporting fluid. The inner ferrules and the outer ferrules can be configured to be secured together in a manner such that flow channels are formed between the inner and the outer ferrules. The flow channels can be fluidly coupled to the outer flow channel  324 . The flow channels between the inner ferrules and outer ferrules can allow fluid which accumulates in the outer flow channel to be transported between the inner and outer ferrules and out an exit between the inner and outer ferrules, such as exit  325  and exit  326 . 
     In some embodiment, the exits, such as exit  325  and  326 , can be sealed. Thus, any fluid accumulated in the outer flow channel  324  and between the inner and outer ferrules can be contained. However, a window and/or sensors can be used at the sealed exits so that the presence of fluid near the exits can be detected and the presence of a leak in the flexible inner hose  322  can be ascertained. 
     Next, a few examples of the interface between the inner ferrules and the outer ferrules is described with respect to  FIGS. 8A and 8B . In particular, cross sectional views,  350   a  and  350   b , of the FDWH connection  300  of  FIG. 6  along cross section line  318  are discussed. In  FIGS. 8A and 8B , the first inner ferrule  310  and the first outer ferrule  308  have a circular cross section. 
     In  FIG. 8A , the first outer ferrule  308  at cross section line  318  includes a first plurality of teeth, such as tooth  352 . The first inner ferrule  310  at cross section line  318  includes a second plurality of teeth, such as tooth  354 . The first plurality of teeth can each include a first aperture and the second plurality of teeth can each include a second aperture. The first plurality of teeth and the second plurality of teeth can be aligned such that the first apertures align with the second apertures. Then, a fastener can be inserted through each of the aligned first apertures and second apertures. For example, fastener  334   b  is inserted through the aligned first aperture and the second aperture in tooth  352  and tooth  354 , respectively. 
     A plurality of flow channels, such as flow channel  356 , can be formed between the teeth. As described above, the plurality of flow channels can be fluidly coupled to the outer flow channel  324 . The plurality of flow channels can allow fluid which has accumulated in the outer flow channel  324  to travel between the inner ferrules and the outer ferrules. 
     In  FIG. 8B , the first outer ferrule  308  at cross section line  318  includes a first flange  358  and the first inner ferrule  310  includes a second flange  360 . The first flange  358  includes first plurality of apertures. The second flange  360  includes a second plurality of apertures. The number and size of the first plurality of apertures and the second plurality of apertures is provided for the purposes of illustration only and is not meant to be limiting. 
     When the first outer ferrule  308  is mechanically coupled to the first inner ferrule  310 , the first plurality of apertures can be aligned with the second plurality of apertures. A first portion of the aligned first plurality and second plurality of apertures can be configured to receive fasteners, such as fastener  334   a  and fastener  334   b . A second portion of the aligned first plurality and second plurality of apertures can be configured to provide flow channels, such as flow channel  362 . The flow channels can allow fluid which has accumulated in the outer flow channel  324  to travel between the inner ferrules and the outer ferrules. 
     Next, a method  400  of assembling the FDWH connection  300  described with respect to  FIGS. 6, 7, 8A and 8B  is described with respect to  FIG. 9 . In  402 , a first end of the flexible inner hose can be inserted a over first surface on the first inner ferrule. In  404 , the first inner swage ring over can be positioned over a first end of the flexible inner hose such that the first end is disposed between the first inner swage ring and the first surface. Then, the first inner swage ring can be swaged to secure the first end of the flexible inner hose to the first surface. 
     In  406 , a second inner swage ring can be inserted over the flexible inner hose. In  408 , the second end of the flexible inner hose can be inserted over a first surface on the second inner ferrule. In  410 , the first inner ferrule and the second inner ferrule can be aligned. In particular, the teeth extending from the first inner ferrule and the teeth extending from the second inner ferrule (see  FIG. 8A ) can be aligned. In another embodiment, first apertures in a first flange extending from the first inner ferrule and second apertures in a second flange extending from the second inner ferrule can be aligned (see  FIG. 8B ). 
     In  412 , a second inner swage ring can be positioned over a second end of the flexible inner hose. After the second inner swage ring is positioned, the second end of the flexible inner hose can be disposed between the second inner swage ring and the first surface on the second inner ferrule. Then, the second inner swage ring can be swaged to secure the second of the flexible inner hose to the second inner ferrule. 
     In  414 , the first end of the flexible outer hose can be inserted over the first surface on the first outer ferrule. In  416 , the first outer swage ring can be positioned over the first end of the flexible outer hose such that the first end is disposed between the first outer swage ring and the first surface on the first outer ferrule. Then, the first outer swage ring can be swaged to secure the first end to the first outer ferrule. 
     In  418 , the second outer swage ring can be inserted over the flexible outer hose. In  420 , the second end of the flexible outer hose can be inserted over the first surface on the second outer ferrule. In  422 , the first outer ferrule and second outer ferrule can be aligned. In particular, the teeth extending from the first outer ferrule and the teeth extending from the second outer ferrule (see  FIG. 8A ) can be aligned. In another embodiment, first apertures in a first flange extending from the first outer ferrule and second apertures in a second flange extending from the second outer ferrule can be aligned (see  FIG. 8B ). 
     In  424 , the second outer swage ring can be positioned over the second end of the flexible outer hose such that the second end is disposed between the second outer swage ring and the first surface on the second outer ferrule. Then, the second outer swage ring can be swaged to secure the second end of the flexible outer hose to the second outer ferrule. 
     In  426 , the inner assembly including the first inner ferrule, the second inner ferrule and the flexible inner hose can be inserted into the outer assembly including the first outer ferrule, the second outer ferrule and the flexible outer hose. In one embodiment, teeth including apertures, which extend from the first inner ferrule, the second inner ferrule, the first outer ferrule and the second outer ferrule, can be aligned. In another embodiment, apertures in flanges, which extend from the first inner ferrule, the second inner ferrule, the first outer ferrule and the second outer ferrule can be aligned. Fasteners can be inserted through the aligned apertures to secure the first inner ferrule to the first outer ferrule and to secure the second inner ferrule to the second outer ferrule. 
     Examples of Aircraft Application 
     An aircraft manufacturing and service method  500  shown in  FIG. 10  is now described to better illustrate various features of processes and systems presented herein. During pre-production, aircraft manufacturing and service method  500  may include specification and design  504  of an aircraft and material procurement  506 . The production phase involves component and subassembly manufacturing  508  and system integration  510  of the aircraft (e.g. see jet  10  in  FIG. 1B ). Some examples of aircraft on which the flexible fluid conduits described herein can be used include military aircraft and commercial aircraft. In particular, commercial aircraft (e.g., see airplane  2  in  FIG. 1A ) modified for military application that have inflight fueling capabilities, such as the presidential transport, C-17 transport, tankers, recon sensor aircrafts can utilize the flexible conduits described herein. 
     System integration can also occur before material procurement  506 . Aspects of the specification and design of a flexible fluid conduit, such as flexible doubled wall hose connection, which can be used with an aircraft, are described above with respect to  FIGS. 2-9 . Thereafter, the aircraft may go through certification and delivery  512  in order to be placed in service  514 . While in service by a customer, the aircraft can be scheduled for routine maintenance and service  516  (which may also include modification, reconfiguration, refurbishment, and so on). While the embodiments described herein relate generally to servicing of commercial aircraft, they may be practiced at other stages of the aircraft manufacturing and service method  500 . 
     Each of the processes of aircraft manufacturing and service method  500  may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include, without limitation, any number of aircraft manufacturers and major-system subcontractors; a third party may include, for example, without limitation, any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
     CONCLUSION 
     Different examples and aspects of the apparatus and methods are disclosed herein that include a variety of components, features, and functionality. In particular, apparatus and methods associated with a flexible fluid conduit, such as a flexible double walled fluid conduit, which can be used on an aircraft, are discussed. It should be understood that the various examples and aspects of the apparatus and methods disclosed herein may include any of the components, features, and functionality of any of the other examples and aspects of the apparatus and methods disclosed herein in any combination, and all of such possibilities are intended to be within the spirit and scope of the present disclosure. 
     Many modifications and other examples of the disclosure set forth herein will come to mind to one skilled in the art to which the disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings.