Method for sealing a fuel tank

• US 9,475,586 B2
• Filed: 10/29/2012
• Issued: 10/25/2016
• Est. Priority Date: 10/28/2011
• Status: Active Grant

• Current Assignee: Daher Aerospace (Sogemarco Daher)
• Original Assignee: Daher Aerospace (Sogemarco Daher)
• Inventors: Hottin, Mathieu, Bailly, Dominique
• Primary Examiner(s): Ellis, Christopher P
• Application Number:
  US14/352,685
• Publication Number:
  US 20140239122A1
• Time in Patent Office: 1,457 Days
• Field of Search: 244/135.R, 244/133, 220/562
• US Class Current: 1/1
• CPC Class Codes: B29C 65/48 using adhesives , i.e. using supplementary joining material; solvent bonding
• CPC Class Codes: B29C 65/562 using extra joining elements, i.e. which are not integral with the parts to be joined using plastic snap elements B29C65/58; using plastic rivets B29C65/601
• CPC Class Codes: B29C 66/721 Fibre-reinforced materials B29C66/729 takes precedence
• CPC Class Codes: B29C 70/08 comprising combinations of different forms of fibrous reinforcements incorporated in matrix material, forming one or more layers, and with or without non-reinforced layers
• CPC Class Codes: B29C 70/086 and with one or more layers of pure plastics material, e.g. foam layers applying a non-preformed coating, e.g. a gel-coat, B29C37/0025; with foam blocks B29C70/86
• CPC Class Codes: B29C 70/88 characterised primarily by possessing specific properties, e.g. electrically conductive or locally reinforced
• CPC Class Codes: B29K 2063/00 Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2071/00 Use of polyethers , e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as moulding material
• CPC Class Codes: B29L 2031/7172 Fuel tanks, jerry cans
• CPC Class Codes: B60K 15/03177 made of non-metallic material, e.g. plastics, or of a combination of non-metallic and metallic material B60K15/03006 takes precedence
• CPC Class Codes: B64C 3/34 Tanks constructed integrally with wings, e.g. for fuel or water
• CPC Class Codes: B64D 37/06 Constructional adaptations thereof
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 156/1062 Prior to assembly

Abstract

A method for making a structural element comprising a panel in composite material with fiber reinforcement in an organic matrix obtained by laying up and curing. The panel comprises a side likely to be exposed to contact with hydrocarbons. The required layer structure is obtained by laying up the plies of fibers pre-impregnated with resin having a curing temperature T1. A ply made of a thin film of polymer that can withstand hydrocarbons and the curing temperature T1, referred to as the protective film, is applied on the side exposed to hydrocarbons. The entire layered structure is cured under pressure at the temperature T1.

Claims

1. A method for making a structural element for use in an aircraft fuel tank comprising a panel in composite material with fiber reinforcement in an organic matrix obtained by laying up and curing, comprising the steps of:

laying up plies of fibers pre-impregnated with resin having a curing temperature T1 to obtain a layered structure;

applying on a side of the panel exposed to hydrocarbons a ply made of a protective film of a polymer that can withstand hydrocarbons and the curing temperature T1, such that the protective film does not entirely cover the side exposed to hydrocarbons, by;

cutting the protective film to a required contour;

projecting a location of areas on the side not covered by the protective film;

applying the protective film on the layered structure away from the areas thus delimited; and

curing entire layered structure under pressure at the curing temperature T1.

2. The method according to claim 1, wherein the organic matrix is made of epoxy thermoset resin;

and wherein the protective film is made of polyetheretherketone (PEEK) polymer that is between 0.015 mm and 0.035 mm thick.

3. The method according to claim 1, further comprising the step of treating one side of the protective film to make it more wettable than a non-treated side of the protective film.

4. The method according to claim 1, wherein the protective film comprises a layer of pressure-sensitive adhesive on one of its sides.

5. The method according to claim 1, further comprising the step of applying the protective film in strips with overlaps at edges of the strips.

6. The method according to claim 1, further comprising the step of compacting the layered structure and the protective film under a vacuum bag before the step of applying.

7. A method for manufacturing a box structure comprising an inside volume configured to contain fuel, comprising the steps of:

obtaining a plurality of parts for the box structure according to the method of claim 1;

assembling the parts to form the box structure; and

sealing of the box structure at the assembly interfaces.

8. The method according to claim 7, wherein the step of assembling is performed by riveting.

9. The method according to claim 7, wherein the step of assembling is performed by gluing.