Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
  • B64D37/00—Arrangements in connection with fuel supply for power plant
  • B64D37/02—Tanks
  • B64D37/06—Constructional adaptations thereof
  • B64D37/08—Internal partitioning
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B5/00—Joining sheets or plates, e.g. panels, to one another or to strips or bars parallel to them
  • F16B5/02—Joining sheets or plates, e.g. panels, to one another or to strips or bars parallel to them by means of fastening members using screw-thread
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
  • B60K15/03—Fuel tanks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
  • B60K15/03—Fuel tanks
  • B60K2015/03118—Multiple tanks, i.e. two or more separate tanks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
  • B60K15/03—Fuel tanks
  • B60K2015/03118—Multiple tanks, i.e. two or more separate tanks
  • B60K2015/03144—Fluid connections between the tanks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
  • B60K15/03—Fuel tanks
  • B60K2015/03118—Multiple tanks, i.e. two or more separate tanks
  • B60K2015/03151—Mechanical connection between the tanks
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/40—Weight reduction
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S220/00—Receptacles
  • Y10S220/905—Flexible fuel tank for a vehicle

Definitions

• the present invention relates to a tank for containing a fluids such as fuel, oil or gas, within a chamber.
• the tank is typically, although not exclusively, installed on a vehicle such as an aircraft.
• US5983945 describes a wing tank liner which limits the amount of fuel that can be spilled in the event of a crash.
• a neoprene rubber liner is suspended within the fuel tank from a frame or from the tank itself.
• a first aspect of the invention provides a tank for containing a fluid within a chamber, wherein the boundaries of the chamber are partially defined by a rigid structure having an opening; and partially defined by an elastomeric diaphragm which is attached around its periphery to the rigid structure and covers the opening.
• the rigid structure may have an element of flexibility, but in general will be more rigid than the elastomeric diaphragm.
• the invention combines the mechanical advantages of a rigid primary structure, with the advantages of an elastomeric diaphragm: namely low density (typically lower than 1.6 Mgm " , and preferably lower than 1.5 Mgm " ) and flexibility.
• low density typically lower than 1.6 Mgm "
• preferably lower than 1.5 Mgm " typically lower than 1.5 Mgm "
• the flexibility of the diaphragm enables it to be easily removed for access to the chamber through the hole in the rigid structure, and then bent or rolled-up to enable it to be stored within a confined space.
• the flexibility of the diaphragm also enables it to transfer loads resulting from pressure pulses into the primary structure more slowly.
• the rigid structure has sufficient flexibility to enable a so-called "morphing" function in which one or more actuators is configured to change the shape of at least part of the rigid structure to which the diaphragm is attached.
• the material forming the diaphragm comprises a reinforcement element such as fabric, randomly oriented short fibres, or any other type of reinforcement.
• a reinforcement element such as fabric, randomly oriented short fibres, or any other type of reinforcement.
• Such reinforcement enables the diaphragm to easily support both hydraulic/pneumatic loads and structural loadings.
• the orientation and/or distribution of the reinforcement can be tailored to provide increased stiffness in one or more direction relative to other directions.
• the diaphragm may have fluid on one side only, or may define at least part of a dividing wall between two tank chambers - in other words with fluid on both sides.
• an attachment frame engages the diaphragm and the rigid structure, and extends around the periphery of the diaphragm.
• This frame may be bonded or welded to the rigid structure, or more preferably attached to the rigid structure by a plurality of fasteners which are distributed around the periphery of the diaphragm, each fastener passing through the thickness of at least the attachment frame and the rigid structure.
• the fastener may pass through the diaphragm.
• reinforcing material can be provided around the fastener holes.
• the attachment frame has a first portion which engages the diaphragm, and a second portion which is positioned outside an outer edge of the diaphragm and attached to the rigid structure.
• the second portion of the attachment frame comprises a plurality of holes which pass through the thickness of the attachment frame, each hole receiving a respective fastener which attaches the attachment frame to the rigid structure.
• At least one external face of the diaphragm may comprises one or more protrusions and/or indentations which engage the attachment frame. These protrusions/indentations may extend as elongate ridges or channels round the entire periphery of the diaphragm, or may be more limited in length.
• the tank is a fuel tank.
• the invention may also be used in other types of tank: for instance for containing hydraulic fluids, oils (for instance in aircraft bilge areas) or pressurised gas (for instance aircraft fuselage pressure covers).
• the diaphragm material must be carefully selected for the application - for instance a hydraulic oil resistant diaphragm could be made from ethylene propylene diene monomer (EPDM) rubber with a glass reinforcement and aluminium attachment frame.
• EPDM ethylene propylene diene monomer
• Figure 1 is an isometric view of a fuel tank
• Figure 2 is a sectional view of the diaphragm
• Figures 9 and 10 are sectional views of further clamping arrangements
• Figure 12 is a second schematic sectional view of the wing-box of Figure 11.
• Figure 13 is a schematic plan view of a wing-box with the upper and lower skins removed.
• the material forming the diaphragm 8 comprises a reinforcement fabric element 11 (in this case four separate layers of fabric) impregnated with an elastomeric matrix 12.
• the elastomeric matrix 12 may comprise a fluorosilicone rubber, for example. This is an inert material which will not corrode and therefore does not require painting or pre -treatment.
• An internal interleaf 13 of stiff material is bonded within the diaphragm and extends around its periphery.
• the diaphragm material typically has a relatively low density between 1.35 Mgm " and 1.55 Mgm "3 . Also the material volume of the diaphragm can be lower than traditional materials as external stiffening ribs do not need to be added. These two factors combine to reduce the mass of the fuel tank by a substantial amount.
• the diaphragm can be removed, rolled up and passed out of the confined wing area through a manhole (not shown).
• Metallic or composite doors have to remain within the wing as they are usually too bulky to pass through the manhole.
• the diaphragm is fastened to the airframe and feeds loads directly into that airframe. It is also capable of transferring loads from one end of the diaphragm to the other as a rigid boundary would. As well as being sufficiently flexible to be removable from the wing, the diaphragm must be stiff enough to resist hydraulic pressure pulses created by high-G manoeuvres of the aircraft. Tests with a 400mm by 400mm diaphragm have shown that it is able to fully contain a 53 psi pulse of compressed air with no leakage and a displacement at the centre of the diaphragm of 35mm.
• Figure 3 is a sectional view along a line A-A in Figure 1. A plurality of fastener bolts are distributed around the periphery of the diaphragm, each fastener passing through the thickness of the attachment frame 9 and the rib 5 as shown in Figure 3.
• Each bolt has a shaft with a threaded distal end 14 which passes through holes in the rib 5, diaphragm 8 and attachment frame 9.
• the head 15 of the bolt engages the face of the rib 5, and a nut 16 is screwed onto the shaft and bears against a washer 17 which in turn bears against the face of the frame 9.
• the attachment frame 9 has a channel section as shown in order to provide a strong calming force between the fasteners - at a point mid fastener pitch to oppose the reaction to exerted load (in the y direction) this must exceed the reaction load y to give acceptable sealing.
• the flexible diaphragm 8 is manufactured without the interleaf 13.
• the perimeter of the diaphragm contains a fully encapsulated bonded wire 20.
• a channel 21 is moulded in an external face 22 of the diaphragm.
• the wire 20 extends around the full periphery of the diaphragm, and is positioned closer to its outer edge 25 than the channel 21.
• An aluminium attachment frame extends around the full periphery of the diaphragm.
• the attachment frame has a return portion 24 which is received in the channel 21, and a peripheral portion 23 which is positioned outside an outer edge 25 of the diaphragm and attached to the rib 5 by bolts.
• the tension load, x is transferred from the diaphragm into the attachment frame using the bonded wire 20 as an anchor locked in place by the return 24 in the attachment frame.
• the peripheral position of the portion 23 allows the fastener load to be transferred directly into the rib 5 removing the need for the ferrule 18.
• the modified section of the wire 20 still has to provide a strong calming force between the fasteners - at a point mid fastener pitch to oppose the reaction to exerted load (in the y direction) this must exceed the reaction load y to give acceptable sealing.
• Figure 6 presents an alternative option for a bonded diaphragm clamp where the attachment frame 40 is bonded and encapsulated within the diaphragm 8. This gives higher bond strength than the Figure 5 solution and would be suitable where higher loads are anticipated.
• An attachment frame 72 clamps the diaphragm 70 to the rib 5.
• a fastener shaft 73 passes through the frame 72, diaphragm 70 and rib 5.
• the frame 72 has a bent section 74 defining a channel 75 which receives the protrusion 71.
• Figure 10 is a sectional view of a further alternative diaphragm 80 and clamping assembly.
• the diaphragm 80 is similar to the diaphragm 70 and has a protrusion 81 on its upper surface.
• An attachment frame clamps the diaphragm 80 to the rib 5.
• the attachment frame has an outer portion 82 which is fastened to the rib 5, and an inner portion with a bent section 83 defining a channel 84 which receives the protrusion 81.
• the diaphragm is attached to a planar rib 5 which lies substantially in the same plane as the diaphragm.
• the diaphragm may completely replace the rib 5, and be attached around its periphery by flanges to the spars 3,4 and skins 2,3.
• a wing- box 92 comprises an upper skin 1, lower skin 2, leading edge spar 3, and trailing edge spar 4.
• the ribs of a conventional wing-box are replaced by elastomeric diaphragms 90, similar to the diaphragm 8 shown in Figure 1.
• Each diaphragm 90 is connected at its periphery to the covers 1 ,2 and the spars 3 ,4, using an attachment arrangement similar to one of the arrangements shown in Figures 4-10.
• Elements 1-4 and 90 define the boundaries of five fuel tank chambers.
• Hydraulic rams 91 act between the upper and lower skins 1,2, and can be expanded and contracted in order to provide a so-called "morphing" wing structure. Note that only one ram is shown in each chamber but in practice a larger number of such rams may be provided.
• the elastomeric diaphragms 90 can flex to accommodate the flexing of the upper and lower skins, as well as being sufficiently strong to contain span-wise fuel pressure pulses.
• the fabric reinforcement in the diaphragms 90 can be tailored to provide increased stiffness in one or more direction.
• the diaphragm can be made flexible in the Z-direction between the skins 1,2, but stiff er in the other two orthogonal X and Y directions.
• a further alternative arrangement is shown in Figure 13.
• a wing-box 93 comprises upper and lower skins (not shown) a leading edge spar 3, a trailing edge spar 4 and a series of six rigid ribs 96.
• Elastomeric diaphragms 97 similar to the diaphragms 8,90, run in a spanwise direction.
• Each diaphragm 97 is connected at its periphery to the skins (not shown) and an adjacent pair of ribs 96, using an attachment arrangement similar to one of the arrangements shown in Figures 4-10. Elements 94-97 and the upper and lower skins (not shown) define the boundaries of ten fuel tank chambers. The diaphragms 97 protect the front spar 94 from the chordwise fuel pressure pulse resulting from a crash of the aircraft.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Aviation & Aerospace Engineering (AREA)
• Mechanical Engineering (AREA)
• Diaphragms And Bellows (AREA)
• Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Infusion, Injection, And Reservoir Apparatuses (AREA)
• Closures For Containers (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Pens And Brushes (AREA)
• External Artificial Organs (AREA)

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• 2007
  • 2007-10-19 GB GBGB0720406.8A patent/GB0720406D0/en not_active Ceased
• 2008
  • 2008-10-16 CA CA2699795A patent/CA2699795C/en not_active Expired - Fee Related
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  • 2008-10-16 EP EP08806756A patent/EP2200901B1/en not_active Not-in-force
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  • 2008-10-16 WO PCT/GB2008/050942 patent/WO2009050510A1/en not_active Ceased
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