WO2012088055A1 - Aircraft fuel handling system - Google Patents

Aircraft fuel handling system Download PDF

Info

Publication number
WO2012088055A1
WO2012088055A1 PCT/US2011/066067 US2011066067W WO2012088055A1 WO 2012088055 A1 WO2012088055 A1 WO 2012088055A1 US 2011066067 W US2011066067 W US 2011066067W WO 2012088055 A1 WO2012088055 A1 WO 2012088055A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
tube
electrically conductive
made
inner
retainer
Prior art date
Application number
PCT/US2011/066067
Other languages
French (fr)
Inventor
William T. Flynn
Original Assignee
Eaton Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16LPIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L25/00Constructive types of pipe joints not provided for in groups F16L13/00 - F16L23/00 ; Details of pipe joints not otherwise provided for, e.g. electrically conducting or insulating means
    • F16L25/01Constructive types of pipe joints not provided for in groups F16L13/00 - F16L23/00 ; Details of pipe joints not otherwise provided for, e.g. electrically conducting or insulating means specially adapted for realising electrical conduction between the two pipe ends of the joint or between parts thereof
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64DEQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D37/00Arrangements in connection with fuel supply for power plant
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B64AIRCRAFT; AVIATION; COSMONAUTICS
    • B64DEQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D45/00Aircraft indicators or protectors not otherwise provided for
    • B64D45/02Lightning protectors; Static dischargers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16LPIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L27/00Adjustable joints, Joints allowing movement
    • F16L27/12Adjustable joints, Joints allowing movement allowing substantial longitudinal adjustment or movement
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16LPIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L3/00Supports for pipes, cables or protective tubing, e.g. hangers, holders, clamps, cleats, clips, brackets
    • F16L3/16Supports for pipes, cables or protective tubing, e.g. hangers, holders, clamps, cleats, clips, brackets with special provision allowing movement of the pipe
    • F16L3/18Supports for pipes, cables or protective tubing, e.g. hangers, holders, clamps, cleats, clips, brackets with special provision allowing movement of the pipe allowing movement in axial direction
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16LPIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L37/00Couplings of the quick-acting type
    • F16L37/50Couplings of the quick-acting type adjustable; allowing movement of the parts joined
    • F16L37/505Couplings of the quick-acting type adjustable; allowing movement of the parts joined allowing substantial longitudinal adjustment or movement

Abstract

A fuel handling system having a tube connection system for sealingly connecting two sections of metallic tubes with one section of non-metallic tube while allowing longitudinal misalignment for use in an aircraft fuel system and for providing a specified electrical resistance. More specifically, a tube connection system for sealingly connecting two sections of metallic tubes with one section of non-metallic tube in an aircraft fuel system allowing for relatively long sections of continuous tube lengths. Compliant electrically conductive tube support devices for supporting the tubes in the aircraft structure allow for increased compliance of the fuel handling system and providing for a specified electrical resistance without using an electrical bonding system.

Description

AIRCRAFT FLUID HANDLING SYSTEM

Claim of Priority

This application claims the benefit of provisional application Serial No. 61/425,052 filed on December 20, 2010, entitled "Aircraft Fuel Handling System".

Technical Field

A fuel handling system for an aircraft that provides a specified electrical resistance using electrically conductive polymeric tubing in conjunction with electrically conductive 0- rings for fluid sealing and electrical conduction at the connecting joints between the sections of tubing.

Background

The current fluid conveyance systems such as fuel handling systems on aircraft include sections of metallic tubing that are connected together using flexible or rigid tubing connectors. Prior art systems include a multiple of miscellaneous tube fittings, including tees, crosses, elbows, step size fittings and various combinations of other fittings and components. The resulting tube assembly uses a multitude of component support devices to connect the multitude of tube segments of the tubing system to the aircraft structure. The tubing system in conjunction with the component support devices must move with the wing and/or other aircraft structure without imposing any additional loads or restricting the normal wing motion. The present rigid metal tube based systems use many short sections of tube and a like number of connectors to permit the needed compliance in the fuel system. The fuel handling system also must now include an electrical bonding system which electrically connects each and every individual fluid handling component directly or indirectly to the aircraft's electrical bonding grid to prevent electrical discharge between components of differing electrical potential. An electrical discharge can result in ignition of fuel vapors and a resulting in-flight emergency.

Metallic skinned aircraft with metallic internal support structure are typically plumbed with an all metallic fluid handling components. The electrical resistance between any fluid handling component and the bonding grid is typically one ohm or less. Couplings are usually electrically connected to the tubing and to the aircraft structure. Hybrid skinned aircraft with a combination of metallic skin and composite skin have been plumbed with a hybrid fluid handling system that includes both metallic and non- metallic components. The electrically conductive non-metallic components provide an electrical isolation function and reduce the amplitude of electric currents that flow between adjacent metallic components during lightning strike events while still providing a highly resistive electrical current path for static electrical current flows to the aircraft bonding grid. The electrical resistance between these electrically isolated components is typically mega- ohm or greater. The component resistances are carefully engineered to dissipate high voltages and to prevent electrical sparks.

Elastomeric o-rings are the main sealing elements used between almost all connected discrete fuel handling devices. The o-rings elastic properties provide a required level of compliance at all operational levels of temperature and pressure so as to provide the required level of fluid sealing between the tubing sections and between certain fluid handling components. It would be desirable to use o-rings to seal between sections of non-metallic sections of fluid handling tubing. Again, it would be mandatory that this system exhibit an electrical charge dissipation capability such that no electrical discharge can take place during operation.

The operation problem presented when using the prior art designs for fluid handling systems using metallic tubing is that there can be a build-up of electrical energy in the tubing during a lighting strike or by the conveyance of fuel creating an electrical potential between the tubing and the aircraft skin or structure. This electrical potential can result in an electrical discharge in the form of a spark that can damage certain aircraft components resulting in failure of the aircraft. It would be desirable to use a non-metallic fluid handling tubing that exhibited some compliance so that longer sections of tubing could be used to reduce the number of joints and connectors in the fluid handling system. It would be mandatory that this system exhibit an electrical charge dissipation capability such that no electrical discharge can take place during operation.

Summary

Composite skinned aircraft with a metallic and/or non-metallic internal structure may be plumbed with metallic and non-metallic fluid handling components. This hybrid system may include all non-metallic tubing plumbing system. The non-metallic tubing system provides an electrical isolation function and can reduce the level of electric current that will flow between adjacent non-metallic tubing components during certain lightning strike events. The non-metallic tubing system also provides a highly resistive electrical current path for transmitting any and all static electrical current generated from the fuel flow to the aircraft bonding grid. The electrical resistance between any section of non-metallic tubing and the electrical bonding grid is typically 5 K ohms or greater. This is the resistance of the two o- ring seals used in the exemplary fuel handling system at each connector.

A fuel handling system for an aircraft that provides a specified electrical resistance using electrically conductive polymeric tubing in conjunction with electrically conductive 0- rings for fluid conveyance, sealing and electrical conduction at the connecting joints between the sections of tubing, where the stiffness of the system is designed to match the requirements of the airframe manufacturer by proper selection and engineering of the polymer, of the thickness of the tubing and of the geometry of the connecting joints. At least two electrically conductive O-rings are used in each connecting joint for sealing and electrical conductivity redundancy, where the stiffness of the system is designed to match the requirements of the airframe manufacturer by proper selection and engineering of the polymer, of the thickness of the tubing and of the geometry of the connecting joints. At least two electrically conductive O-rings are used in each connecting joint for sealing and electrical conductivity redundancy.

Since the fuel handling system on an aircraft consists of various tubing sizes, and have various wall cross-sectional areas, the fixed end to end resistance will also be different for the various tubes. Since the total system must have its end-to-end resistance fall within a selected resistance range, there can be several different material formulas for the tubes (% polymer and % conductive filler) as used in a given aircraft model application. Thus, the fuel handling system must be carefully engineered for each aircraft model to obtain the desired pressure, temperature and electrical characteristics.

The use of polymeric tubing for fuel handling in an aircraft, especially a composite aircraft offers several advantages as compared to the prior art rigid metallic designs. The tubing itself is more flexible than its rigid metallic counterpart (for example) aluminum or filament wound, so fewer flexible connecting joints are required (approximately half the number for a single aisle commercial jet transport). The reduction in the number of connecting joints reduces the number of sealing locations and increases the overall reliability of the fuel system. In the prior art rigid tube system many more connecting joints are needed since the connecting joints used with the aluminum systems as needed to provide some degree of flexibility. Since the wing structure flexes to a significant extent when in extreme flight regimes, there needs to be a significant degree of flexibility built into the fuel handling system which extends the span of the wing itself. Rigid tubing requires the use of many connecting joints to provide this overall system flexibility because the tubing sections are rigid and need to be relatively short.

Unlike aluminum, polymeric tubing is quite flexible but it has sufficient stiffness to maintain its form between supports so that any water in the fuel does not accumulate at low points between the supports. This is the reason that fuel hose cannot be used in this application. The polymeric material provides the proper stiffness to minimize the number of connecting joints while maintaining the required form integrity. The tubing stiffness and the tubing supports are engineered to prevent the transmission of unacceptable loads to the wing structure.

The exemplary fuel handling system for an aircraft provides a specified electrical resistance using electrically conductive polymeric tubing in concert with conductive 0-rings for sealing and electrical bonding at the connecting joints. The stiffness of the system is designed to match the requirements of the airframe manufacturer by proper selection and engineering of the polymer, of the thickness of the tubing and of the geometry of the connecting joints. At least two conductive O-rings are used in each connecting joint for sealing and electrical conductivity redundancy.

The conductive o-rings are used in the connecting joints to seal the inner tube to the outer tube and to provide a conductive path between the inner and outer tubes. The o-rings can be made out of nitrile or fluorosilicone or fluorocarbon and are filled with carbon powder and/or carbon nano tubes. Commercially available o-rings of this type are made by Parker Seals or Jackson Flex Products. The o-rings are retained on the inner tube by an integral tube collar that includes circular grooves formed in the tube collar. These grooves are formed either by molding three concentric rings or chemical bonding the tube collars to the outside surface of the tube or by machining three grooves in the tube collar outside surface. Two grooves are for o-ring retention. The inner tube with the tube collar and o-rings slides inside the outer tube. At a first end of the outer tube a bulkhead connector is formed while on a second end, a retainer flange is formed. The retainer flange includes a retainer slot that holds a retaining clip in position. The retainer clip extends through the inner wall of the outer tube so as to engage a circumferential collar slot formed in a slipping retainer collar. The retainer collar is shaped to slip on the outside of the inner tube and has an outside diameter that slips inside of the outer tube. The retainer collar hits against the tube collar when the inner tube is withdrawn from the outer tube. Thus, the retainer slip and the retainer collar secure the two tubes together while permitting some axial movement. Thus, the retaining clip holds the inner tube inside the outer tube. The o-rings are compressed between the inner wall of the outer tube to provide sealing and to establish an electrical path between the inner and outer tubes.

The proper range for the electrical resistance of this fuel handling system is about from 100K to 3M ohms per meter length of tubing regardless of tube size or tube cross sectional area. This level of resistance provides sufficient conductivity for the conduction of static electricity and sufficient resistivity for the dissipation of indirect high voltage electrical effects from lightning strikes. If the resistance is too low, the electrical current from a lighting strike is not dissipated sufficiently and would be conducted throughout the fuel handling system. If the resistance is too high, the rate of static electricity generation and storage will be greater than the rate of static electricity conduction to ground. In either case, an unsatisfactory condition is a possibility so detailed engineering is required,

A new type of a center tube support device can be used as part of the overall system. These electrically conductive tube support devices include a pair of interlocking, electrically conductive, crescent shaped, elastomeric inserts or cushions; a pair of interlocking, electrically conductive, crescent shaped, metallic or polymeric support frames. The cushioned inserts can be separate or over-molded to the support frames. The insert can include an inside radiused surface, where said inside radiused surface contacts outside surface of the tube and includes a front flat and rear flat stepped surface. The front and rear surfaces contact inside surfaces of the support frames as well as contacting the aircraft support structure. The insert can include an outside radiused surface that contacts the inside wall of the support frame. The insert can also have elastomeric properties that provide for clamping compliance yet limit the axial tube travel and motion dampening while providing an electrical current path from the polymeric tube surface to the aircraft bonding grid. The tube support device provides protection for the tube outer surface for passing the tube through the aircraft structure. Brief Description of the Drawings

FIG. 1 is an exploded perspective view of a fluid connector system used in the fluid handling system;

FIG. 2 is a partial perspective view of the inner tube component of the fluid connector system;

FIG. 3 is a partial plan view of the inner tube component of the fluid connector system;

FIG. 4 is a cross-sectional view of the assembled inner and outer tube components of the fluid connector system;

FIG. 5 is a front perspective view of a tube support device;

FIG. 6 is a rear perspective view of the tube support device;

FIG. 7 is a perspective view of the front portion of the tube support device disassembled;

FIG. 8 is a perspective view of the rear portion of the tube support device disassembled.

Detailed Description

Referring now to the discussion that follows and also to the drawings, illustrative approaches to the disclosed systems and methods are shown in detail. Although the drawings represent some possible approaches, the drawings are not necessarily to scale and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain the present disclosure. Further, the descriptions set forth herein are not intended to be exhaustive or otherwise limit or restrict the claims to the precise forms and configurations shown in the drawings and disclosed in the following detailed description. Moreover, a number of constants may be introduced in the discussion that follows. In some cases illustrative values of the constants are provided. In other cases, no specific values are given. The values of the constants will depend on characteristics of the associated hardware and the interrelationship of such characteristics with one another as well as environmental conditions and the operational conditions associated with the disclosed system.

Now referring to FIG. 1 of the drawings, an exploded perspective view of the tube connection system 10 showing the outer tube assembly 12, an inner tube assembly 14, two o- ring seals 16, 18 and a retainer clip 20. Upon assembly, the tube collar 22 of the inner tube assembly 14 is inserted into the outer tube section 12. The two o-ring seals 16, 18 are retained in the tube collar 22 and are positioned to contact the interior of the outer tube 13 when the inner tube assembly 14 is inserted into the outer tube assembly 12 thereby providing a fluid seal between the inner tube 15 and the outer tube 13. The o-rings can be made out of nitrile or fluorosilicone or fluorocarbon and are filled with carbon powder and/or carbon nano tubes. These o-rings are made by Parker Seals or Jackson Flex Products are electrically conductive and electrically connect the outer and inner tube assemblies 12, 14 to one another in addition to providing a fluid seal. The outer tube 13 can be made of a metallic material or out of a polymeric material having a specified level of electrical resistance. More specifically, the outer tube 13 and the inner tube 15 preferably have values of electrical resistance of about 5,000 ohms up to about 3.25 M ohms per linear meter of tube length.

The outer tube assembly 12 is held onto the inner tube assembly 14 by the retainer clip 20 and the retainer collar 21. The retainer clip 20 fits into a retainer slot 34 and then into a collar slot 33 formed in the retainer collar 21 after the inner tube assembly 14 is inserted into the outer tube assembly 12. The retainer collar 21 slips onto the inner tube 15 and has an outside diameter that allows it to slip into the outer tube 13. The retainer slip 20 engages the retainer slot 33. As the inner tube assembly 14 is withdrawn from the outer tube assembly 12, the retainer collar 21 hits against the tube collar 22 to retain the inner and outer tube assemblies 12, 14 together. FIG. 1 shows only a partial length of the inner tube assembly 14 and normally there will be a tube collar 22 at each end. The retainer collar 21 is made of an electrical non-conductive material such as nylon 6. The retainer collar 21 acts to electrically insulate the retainer clip 20 from the inner tube 15. Now referring to FIG. 2 of the drawings, a partial perspective view of the inner tube assembly 14 is shown. The inner tube assembly 14 is made up of a length of polymeric tubing 15 that is quite flexible but it has sufficient stiffness to maintain its form between the tube supports that will be utilized in most aircraft installations. The polymeric tube 15 is electrically conductive which meets the electrical dissipation requirements for use in aircraft fuel systems. In the tube collar 22 are a plurality of seal grooves 24 and 26 that are designed to hold respective electrically conductive o-ring seals 16, 18. The tube ends 22 is divided into a plurality of sections between the seal grooves 24, 26 and are identified as inner land bearing 28, middle land bearing 30 and outer land bearing 32. These land bearings 28, 30, 32 are sized to loosely fit inside of the outer tube 13 sufficient to permit the inner tube assembly 14 to be operational while at a longitudinal angle relative to the outer tube assembly 12. At the larger relative angles, the middle land bearing 30 will not be in contact with the inside of the outer tube 13 but the inner and outer land bearings 28, 32 will be in contact with the inside of the outer tube 13.

Each of the o-rings 16 and 18 are typically made of a nitrile, fluorosilicone or fluorocarbon base material and are each filled with some type of electrically conductive material such as carbon powder or carbon nano tubes. These electrically conductive o-ring seals 16, 18 provide for the conduction of electricity such as static electricity from the inner tube assembly 14 to the outer tube assembly 12 and vice versa. This is a mandatory function to minimize the chance of the ignition of fuel vapors by the electricity introduced into the airframe by a lightning strike.

The outer tube assembly 12 is held onto the inner tube assembly 14 by the retainer clip 20 and the retainer collar 21. The retainer clip 20 fits into a retainer slot 34 and then into a collar slot 33 formed in the retainer collar 21 after the inner tube assembly 14 is inserted into the outer tube assembly 12. The retainer collar 21 slips onto the inner tube 15 and has an outside diameter that allows it to slip into the outer tube 13. The retainer slip 20 engages the retainer slot 33. As the inner tube assembly 14 is withdrawn from the outer tube assembly 12, the retainer collar 21 hits against the tube collar 22 to retain the inner and outer tube assemblies 12, 14 together. FIG. 1 shows only a partial length of the inner tube assembly 14 and normally there will be a tube collar 22 at each end. The retainer collar 21 is made of an electrical non-conductive material such as nylon 6. The retainer collar 21 acts to electrically insulate the retainer clip 20 from the inner tube 15. Now referring to FIG. 3 of the drawings, a front plan view of the inner tube assembly 14 is shown having a tube collar 22 at both ends of the tube assembly 14. This configuration is the one that can be used in aircraft to carry fluids such as aviation and jet fuel. The length of this inner tube assembly 14 can be selected to provide the required degree of rigidity between possible tube supports (see FIGS. 5-8). The stiffness of the tube will depend on the length and the properties and operating environment of the tube. The inner and outer tubes 13, 15 can be made of a variety of non-metallic materials such as polymeric materials including nylon, Viton, etc. The selection of the material depends on the fluid to be transported and on the pressures involved. To be used in a commercial aircraft now, the material must exhibit a minimum level of electrical conductivity to prevent the build-up of electrical charge so that a spark is not generated when a discharge takes place. It is also necessary to prevent the generation of electrical sparks during a lightning strike. To properly set the electrical conductivity of the inner and outer tubes 13, 15, the polymeric material can be loaded with a conducting material such as carbon powder or carbon nano tubes. The total system electrical resistance needs to lie between lOOKohm and 3.25 mOhm per running meter of system length to properly function in an aircraft environment carrying jet fuel. The resistance needs to be high enough to dissipate lightning strikes while providing enough conductivity to prevent electrical sparking. Other applications will require different attributes which can be accomplished using different base materials and different loading materials in select quantities.

Now referring to FIG. 4 of the drawings, a partial cross-sectional view of a fluid connector system 10 is shown in an assembled configuration. The inner tube assembly 14 has been inserted into the outer tube assembly thereby sealing the flow of fluid through the fluid connector system 10. To secure the inner tube assembly 14 to the outer tube assembly 12, the retainer clip 20 is shown inserted into the retainer slot 34. The inner tube assembly 14 cannot be pulled out of the outer tube assembly 12 because the retainer clip 20 will hit against the inner land 28 of the tube collar 22.

Several components of the inner tube assembly 14 can contact the inner wall of the outer tube 13 including the inner land 28, the o-ring seal 16, the middle land 30, the o-ring seal 18 and the outer land 32. The two or more o-ring seals 16, 18 provide the fluid sealing function while the lands 28, 30, 32 provide the structural alignment between the two tube assemblies 12, 14. The o-rings 16, 18 occupy their respective seal grooves 24, 26 formed in the tube collar 22. The lands 28, 30 and 32 are sized to allow for some 5 degrees of relative angular misalignment between the outer and inner tube assemblies 12, 14. In the extreme case, the middle land 30 is not touching the inner wall of the outer tube 13. In the neutral case, none of the lands 28, 30 or 32 are touching the inner wall of the outer tube 13, only the o-ring seals 16, 18 are touching and providing the fluid seal.

The outer tube assembly 12 includes a retainer flange 35 that has the retainer slot 34 formed therein for containment of the retainer clip 20. At the opposite end of the outer tube assembly 12 is a mounting flange 36 for attachment to some part of the aircraft structure or to another component of the fuel handling system.

The outer tube assembly 12 is held onto the inner tube assembly 14 by the retainer clip 20 and the retainer collar 21. The retainer clip 20 fits into a retainer slot 34 and then into a collar slot 33 formed in the retainer collar 21 after the inner tube assembly 14 is inserted into the outer tube assembly 12. The retainer collar 21 slips onto the inner tube 15 and has an outside diameter that allows it to slip into the outer tube 13. The retainer slip 20 engages the retainer slot 33. As the inner tube assembly 14 is withdrawn from the outer tube assembly 12, the retainer collar 21 hits against the tube collar 22 to retain the inner and outer tube assemblies 12, 14 together. FIG. 1 shows only a partial length of the inner tube assembly 14 and normally there will be a tube collar 22 at each end. The retainer collar 21 is made of an electrical non-conductive material such as nylon 6. The retainer collar 21 acts to electrically insulate the retainer clip 20 from the inner tube 15.

Now referring to FIG. 5 of the drawings, a perspective front view of a tube support device 50 is shown. The tube support device 50 is used to support the inner and outer tube assemblies 12, 14 in the internal structure of the aircraft while providing some compliance to accommodate movement of the aircraft structure such as a wing in turbulent conditions. In addition to the compliance of the tube support device 50, the inner tube 15 offers increased compliance over a similar length of metallic tube.

The tube support device 50 consists of two component assemblies, a mounting bracket assembly 52 and an insert assembly 56. The mounting bracket assembly 52 which can be made of a metallic material or out of an electrically conductive non-metallic material includes at least one mounting flange 54 for attachment to the aircraft structure. The insert assembly 56 is preferably made out of a compliant polymeric material that has been made electrically conductive with the addition of carbon powder or carbon nano tubes. Various alternative materials could be used so long as they are compliant and electrically conductive.

Now referring to FIG. 6 of the drawings, a perspective rear view of the tube support device 50 is shown. The tube support device 50 is used to support the inner and outer tube assemblies 12, 14 in the internal structure of the aircraft while providing some compliance to accommodate movement of the aircraft structure such as a wing in turbulent conditions. In addition to the compliance of the tube support device 50, the inner tube 15 offers increased compliance over a similar length of metallic tube.

The tube support device 50 consists of two component assemblies, a mounting bracket assembly 52 and an insert assembly 56. The mounting bracket assembly 52 which can be made of a metallic material or out of an electrically conductive non-metallic material includes at least one mounting flange 54 for attachment to the aircraft structure. The mounting bracket assembly is more clearly shown in FIG. 6 as consisting of two interconnecting parts, a first bracket 58 and a second bracket 60. The insert assembly 56 is preferably made out of a compliant polymeric material that has been made electrically conductive with the addition of carbon powder or carbon nano tubes. Various alternative materials could be used so long as they are compliant and electrically conductive. As shown in FIG. 6, the insert assembly 56 is made up of two parts, a first insert 62 which engages a second insert 64.

Now referring to FIG. 7, an exploded perspective view of the tube support device 50 is shown. The tube support device 50 consists of two component assemblies, a mounting bracket assembly 52 and an insert assembly 56. The mounting bracket assembly 52 which can be made of a metallic material or out of an electrically conductive non-metallic material includes at least one mounting flange 54 for attachment to the aircraft structure. The mounting bracket assembly is more clearly shown in FIG. 7 as consisting of two interconnecting parts, a first bracket 58 which overlaps and engages a second bracket 60. The insert assembly 56 is preferably made out of a compliant polymeric material that has been made electrically conductive with the addition of carbon powder or carbon nano tubes. Various alternative materials could be used so long as they are compliant and electrically conductive. As shown in FIG. 7, the insert assembly 56 is made up of two parts, a first insert 62 which overlaps and engages a second insert 64.

Also shown is how the first bracket 58 overlaps and engages a second insert 64. This is also illustrated in FIG. 8. Using this type of construction, the tube support device 50 can be installed on the outer or inner tube 13, 15 after they are assembled in the airframe.

Now referring to FIG. 8, an exploded perspective view of the tube support device 50 is shown. The tube support device 50 consists of two component assemblies, a mounting bracket assembly 52 and an insert assembly 56. The mounting bracket assembly 52 which can be made of a metallic material or out of an electrically conductive non-metallic material includes at least one mounting flange 54 for attachment to the aircraft structure. The mounting bracket assembly is more clearly shown in FIG. 6 as consisting of two interconnecting parts, a first bracket 58 which overlaps and engages a second bracket 60. The insert assembly 56 is preferably made out of a compliant polymeric material that has been made electrically conductive with the addition of carbon powder or carbon nano tubes. Various alternative materials could be used so long as they are compliant and electrically conductive. As shown in FIGS. 7&8, the insert assembly 56 is made up of two parts, a first insert 62 which overlaps and engages a second insert 64. Also shown is how the first bracket 58 overlaps and engages a second insert 64. Using this type of construction, the tube support device 50 can be installed on the outer or inner tube 13, 15 after they are assembled in the airframe.

In all of the embodiments, the resistance RT across the total length of the inner tube 15 must fall within a range of a lower limit of (100,000 ohms x length of the inner tube 15), and an upper limit of (2.5 M ohms x length of the inner tube 15). The proper value of RT will ensure the proper electrical functioning of the aircraft fuel system under adverse electrical conditions such as a lightning strike without using a prior art electrical bonding system.

In all of the embodiments, for proper electrical functioning in an aircraft fuel system, the installed system resistance along the inner tube 15 to the mounting flange 36 must meet specified requirements. The resistance measurement point is slightly outside of the end of the retainer flange 35 at the surface of the inner tube 15 and the resistance value RA must fall between a lower and an upper limit to confirm the proper functioning of the o-ring seals 16, 18. If two conductive o-ring seals 16, 18 are used, the resistance value RA must be at or above 5,000 ohms and less than 500,000 ohms. If defective conductive o-ring seals are used, the resistance will be above 500,000 ohms.

In all of the embodiments, for proper electrical functioning in an aircraft fuel system, the installed system resistance RS from one mounting flange 36 to an opposite mounting flange 36 must fall between a lower limit of (100,000 ohms/meter x total length) and an upper limit of (3.25 M ohms/meter x total length). This system resistance RS ensures that the total resistance of the outer and inner tubes 13, 15 and the o-ring seals 16, 18 combine to fall with a range of values that will result in proper electrical functioning in all adverse operational conditions such as during a lightning strike or other electrical discharge type of condition.

The present disclosure has been particularly shown and described with reference to the foregoing illustrations, which are merely illustrative of the best modes for carrying out the disclosure. It should be understood by those skilled in the art that various alternatives to the illustrations of the disclosure described herein may be employed in practicing the disclosure without departing from the spirit and scope of the disclosure as defined in the following claims. It is intended that the following claims define the scope of the disclosure and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the disclosure should be understood to include all novel and non- obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing illustrations are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.

Claims

CLAIMS I claim:
1. A fluid handling system for an aircraft comprising:
a length of electrically conductive polymeric inner tube
a tube collar attached to an end of said inner tube, said tube collar having at least one circumferential groove formed therein;
an electrically conductive seal disposed in said groove in said tube collar;
an electrically conductive outer tube covering the outside diameter of said tube collar, said outer tube having an inner surface contacting said seal; and
a retainer clip mounted to said outer tube and extending inwardly to interfere with said tube collar and prevent the release of the inner tube from the outer tube.
2. The fluid handling system of claim 1, further comprising a retainer collar slipped onto said inner tube and slipped inside of said outer tube, said retainer collar having a circumferential collar slot for engaging said retainer slip.
3. The fluid handling system of claim 1, further comprising a retainer flange formed on one end of said outer tube and having a retainer slot formed therein for holding said retaining clip and permitting said retaining clip to extend past said inner surface.
4. The fluid handling system of claim 1, wherein said inner tube and said outer tube are made of a polymeric material having a given level of electrical resistance.
5. The fluid handling system of claim 1, wherein said inner tube is made of a polymeric material that is loaded with an electrically conductive filler material.
6. The fluid handling system of claim 1, wherein said outer tube is made of a metallic material and said inner tube is made of a polymeric material having a given level of electrical resistance.
7. The fluid handling system of claim 4, wherein said inner tube when connected to said outer tube has a total electrical resistance approximately in the range from 5K ohms to 3, 25 OK ohms per linear meter of said inner and outer tubes.
8. The fluid handling system of claim 1 wherein said inner tube is held in place using a tube support device.
9. The fluid handling system of claim 6 wherein said tube support device includes an insert held by a bracket where said bracket is attached to a inner structure of an aircraft wing.
10. An electrically conductive tube support device comprising:
a first insert and an adjacent second insert, both the first and second inserts being made of electrically conductive material;
a first bracket and an adjacent second bracket, both said first and second brackets surrounding said first and second inserts.
11. The electrically conductive tube support device of claim 10, wherein said first and second inserts are over molded onto said first and second brackets.
12. A method of connecting an inner tube section with an outer tube section comprising: providing an cylindrical tube end at one end of the inner tube section;
providing at least one seal groove in said tube end;
providing at least one seal disposed in said seal groove, said seal having a selected electrical conductivity;
providing an outer tube having an inner surface contacting said seal;
where said inner tube section is made an electrically conductive non-metallic material and where said outer tube is made of a metallic material or a non-metallic material having a given level of electrical resistance.
13. The method of connecting of claim 12 further comprising providing a retainer collar which is slipped onto the inner tube and slipped inside of the outer tube;
providing a retainer slip which secures the retainer collar in position relative to the outer tube, said retainer clip interfering with said tube end to prevent said inner tube from being withdrawn from said outer tube.
14. The method of connecting of claim 13, wherein said retainer collar is made of an electrically non-conductive material.
15. The method of connecting of claim 13 wherein said overall resistance of said outer tube assembly 12 connected to said inner tube assembly 14 section has an electrical resistance that falls approximately in the range of 100,000 ohms/meter up to approximately 3.25 M ohms/meter.
16. The method of connecting of claim 12, wherein said seal is made of nitrile and an electrically conductive filler material.
17. The method of connecting of claim 12, wherein said seal is made of fluorosilicone and an electrically conductive filler material.
18. The method of connecting of claim 12, wherein said seal is made of fluorocarbon and an electrically conductive filler material.
19. The method of connecting of claims 16- 18 wherein said electrically conductive filler material contains a carbon powder.
20. The method of connecting of claims 16-18, wherein said electrically conductive filler material contains carbon nano tubes.
21. A tube support device for holding a fluid handling tube comprising:
an insert surrounding said fluid handling tube, said insert made of an electrically conducting material;
a bracket holding said insert, said bracket attached to a structure for support and said bracket made of an electrically conducting material.
22. The tube support device of claim 21, wherein said insert is made of a polymeric material that is loaded with carbon powder.
23. The tube support device of claim 21, wherein said insert is made of a polymeric material that is loaded with an electrically conductive filler material.
24. The tube support device of claim 21 wherein said electrically conductive filler material is a mixture of carbon powder and carbon nano tubes.
PCT/US2011/066067 2010-12-20 2011-12-20 Aircraft fuel handling system WO2012088055A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US201061425052 true 2010-12-20 2010-12-20
US61/425,052 2010-12-20

Publications (1)

Publication Number Publication Date
WO2012088055A1 true true WO2012088055A1 (en) 2012-06-28

Family

ID=45470720

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2011/066067 WO2012088055A1 (en) 2010-12-20 2011-12-20 Aircraft fuel handling system

Country Status (1)

Country Link
WO (1) WO2012088055A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130081734A1 (en) * 2011-09-29 2013-04-04 The Boeing Company Electrostatic Bonding of Coaxial Tubing
WO2014137567A1 (en) * 2013-03-04 2014-09-12 Eaton Corporation Electrically conductive seals for fluid conveyance systems
FR3015627A1 (en) * 2013-12-19 2015-06-26 Airbus Operations Sas Mounted assembly comprising two pipe elements with an interface joint
WO2015159228A1 (en) * 2014-04-15 2015-10-22 Eaton Corporation Feedback bulkhead connector assembly
WO2015159227A3 (en) * 2014-04-15 2016-01-07 Eaton Corporation Bulkhead connector assembly
WO2017157526A1 (en) * 2016-03-17 2017-09-21 Eaton Limited Aircraft fluid line coupling assembly for releasably interconnecting fluid conveying members
US9797535B2 (en) 2013-04-16 2017-10-24 Eaton Corporation Bonding clip for fluid conduit coupling

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2589876A (en) * 1947-08-07 1952-03-18 William A Sesher Pipe and gasket joint
US3127199A (en) * 1964-03-31 Quick disconnect fitting
WO1996021118A1 (en) * 1994-12-29 1996-07-11 Proprietary Technology, Inc. Connector assemblies which compensate for thermal expansion and contraction of tubular conduits
EP1191268A1 (en) * 2000-09-20 2002-03-27 Ti Group Automotive Systems (Fuldabrück) GmbH Coupling, especially quick coupling,for pipe sections conveying fuel
US20080078880A1 (en) * 2006-09-29 2008-04-03 Airbus Uk Limited Aircraft fuel pipe coupling
US20100045031A1 (en) * 2008-08-20 2010-02-25 Airbus Operations Limited connector for a pipe and bonding means for use therein
US20100122749A1 (en) * 2008-11-20 2010-05-20 Espa Fluid transport device, in particular for fuel
EP2261543A2 (en) * 2009-05-21 2010-12-15 Airbus Operations Limited A connector for a pipe

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3127199A (en) * 1964-03-31 Quick disconnect fitting
US2589876A (en) * 1947-08-07 1952-03-18 William A Sesher Pipe and gasket joint
WO1996021118A1 (en) * 1994-12-29 1996-07-11 Proprietary Technology, Inc. Connector assemblies which compensate for thermal expansion and contraction of tubular conduits
EP1191268A1 (en) * 2000-09-20 2002-03-27 Ti Group Automotive Systems (Fuldabrück) GmbH Coupling, especially quick coupling,for pipe sections conveying fuel
US20080078880A1 (en) * 2006-09-29 2008-04-03 Airbus Uk Limited Aircraft fuel pipe coupling
US20100045031A1 (en) * 2008-08-20 2010-02-25 Airbus Operations Limited connector for a pipe and bonding means for use therein
US20100122749A1 (en) * 2008-11-20 2010-05-20 Espa Fluid transport device, in particular for fuel
EP2261543A2 (en) * 2009-05-21 2010-12-15 Airbus Operations Limited A connector for a pipe

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130081734A1 (en) * 2011-09-29 2013-04-04 The Boeing Company Electrostatic Bonding of Coaxial Tubing
JP2015502501A (en) * 2011-09-29 2015-01-22 ザ・ボーイング・カンパニーTheBoeing Company Electrostatic coupling of the coaxial tubing
WO2014137567A1 (en) * 2013-03-04 2014-09-12 Eaton Corporation Electrically conductive seals for fluid conveyance systems
US9739402B2 (en) 2013-03-04 2017-08-22 Eaton Corporation Electrically conductive seals for fluid conveyance systems
US9797535B2 (en) 2013-04-16 2017-10-24 Eaton Corporation Bonding clip for fluid conduit coupling
FR3015627A1 (en) * 2013-12-19 2015-06-26 Airbus Operations Sas Mounted assembly comprising two pipe elements with an interface joint
WO2015159228A1 (en) * 2014-04-15 2015-10-22 Eaton Corporation Feedback bulkhead connector assembly
WO2015159227A3 (en) * 2014-04-15 2016-01-07 Eaton Corporation Bulkhead connector assembly
WO2017157526A1 (en) * 2016-03-17 2017-09-21 Eaton Limited Aircraft fluid line coupling assembly for releasably interconnecting fluid conveying members

Similar Documents

Publication Publication Date Title
US3734546A (en) Flexible pipe connection
US4635967A (en) Internal seal for insulated steam injection casing assembly
US6402159B1 (en) Dielectric gasket
US4415184A (en) High temperature insulated casing
US4284297A (en) Meter riser
US6971682B2 (en) Coupling assembly
US2789154A (en) Corona shielding
US4793384A (en) Self-damping convoluted conduit
US4712642A (en) Self-damping convoluted conduit
US6854486B2 (en) Fluid line assembly
US20120152611A1 (en) Electrically conductive bushing connection to structure for current path
US2520501A (en) Connector
US3503632A (en) Electrically insulating pipe coupling assembly,particularly for small diameter pipes
US20130183853A1 (en) Electrical Penetrator Assembly
US5307037A (en) Shim lead assembly with flexible castellated connector for superconducting magnet
US20100122749A1 (en) Fluid transport device, in particular for fuel
US20120214328A1 (en) Saddle clamp having electrical bonding character
US3013108A (en) Apparatus for insulation and compensation of electrical conductors for high temperature ambient conditions
US20100077528A1 (en) Clothing and apparel integrated with flexible silicone encased cable systems
US20090287426A1 (en) Elastomeric conductor and shield fault detection
US6936771B2 (en) Superconducting cable termination
US7588057B2 (en) Insulated hose assembly and method of manufacture
US20080169643A1 (en) Dielectric fitting
US8360477B2 (en) Compliant conduit connector
EP0889678A1 (en) Compressible elastomeric contact and mechanical assembly therewith

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11807832

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct app. not ent. europ. phase

Ref document number: 11807832

Country of ref document: EP

Kind code of ref document: A1