WO2024156953A1 - Hybrid flush porthole with improved trade-off between mass, surface and drag - Google Patents

Abstract

The invention relates to a multiple glazing unit of a pressurised enclosure, comprising at least one first external glass panel (1; 2; 3; 4; 5), separated from a second glass panel (7) by an air space (6), by means of a mounting gasket (8), the first glass panel (1; 2; 3; 4; 5) consisting of a first sheet (1) and at least one second sheet (3; 5) glued in pairs by an adhesive layer (2; 4), at least one of the first sheet (1) and the at least one second sheet (3; 5) being made of mineral glass, and another one of the first sheet (1) and the second sheet (3) being made of organic glass with stepped edges, so as to form a cavity for receiving an element of the mounting structure, with the gasket (8) positioned therebetween. The invention also relates to the use thereof as a pressurised aircraft glazing unit.

Description

Description

Title of the invention: HYBRID FLUSH HUBLOT IMPROVING THE MASS COMPROMISE

/ SURFACE / DRAG

The present invention relates to a lightweight aircraft window with low drag, that is to say which, under the effect of the pressurization of the interior volume of the aircraft in flight, does not deform in relation to the fuselage. of the surrounding aircraft, a protrusion (arrow) penalizing from an aerodynamic point of view and the energy consumption to propel the aircraft.

Particularly targeted here are portholes of the type with two slabs separated by an air gap. Such aircraft windows with two slabs of poly(methyl methacrylate) (PMMA) are known. In the event of rupture of the exterior slab, the interior slab makes it possible to maintain the interior volume of the aircraft under a desired pressure. Even if the interior slab (or the peripheral joint with which it is in contact) is commonly provided with a small through hole making it possible to maintain the air blade under the pressure of the interior volume of the aircraft in flight under normal conditions , this interior slab is capable of maintaining this interior volume of the aircraft under the desired pressure in flight in the event of rupture of the exterior slab, because this hole is small enough to maintain a minimal air flow compensated by the conditioning unit aircraft air; in this case, a hissing sound may occur.

The invention more particularly aims to provide such a window having aerodynamic continuity with the fuselage, and having a hybrid composition (mineral - organic) so as to improve the Mass / Surface / Drag compromise. Aerodynamic continuity means that the exterior surface of the window is in perfect continuity with that of the fuselage, that is to say in the absence of any irregularity, protrusion or hollow between the two surfaces. On the other hand, the increase in mass of the window induces a loss of the aircraft's range, as well as its increase in aerodynamic drag. The increase in the surface area of the porthole induces an increase drag at constant mass, or an increase in mass at constant deflection.

This goal was achieved by the invention which relates to multiple glazing to delimit two spaces with variable pressure difference, in particular an enclosure subjected to pressurization, comprising at least a first transparent slab intended to be in contact with the atmosphere exterior in the mounting position, and separated from a second transparent slab by an air gap, by means of a mounting joint in which a peripheral part of the multiple glazing is embedded, characterized in that the first slab is made up of 'a first transparent sheet and at least one second transparent sheet bonded two by two by an adhesive interlayer, in that at least one of the first transparent sheet and the at least one second transparent sheet is in mineral glass, and in that another of the first transparent sheet and the second transparent sheet is made of organic glass and has stepped shaped edges, the edges of an outer fraction of the thickness of this sheet being recessed relative to the edges of its interior complementary fraction, so as to form, where appropriate with the edges of the first sheet and the first adhesive layer, a cavity for accommodating an element of the mounting structure, with the interposition of the mounting gasket.

For the purposes of the invention, the external fraction of the thickness of the shaped organic (polymer) sheet means a part of its thickness closest to the external atmosphere in the mounting position, part of its corresponding thickness, in this case, at edges set back compared to those of the interior complementary part of its thickness, that is to say closer to the interior volume delimited by the glazing, in its mounting position. This interior volume may be the interior of a pressurized aircraft.

The shape of the edge of the porthole, on the exterior atmosphere side, includes a cavity corresponding to the opening made in the mounting structure (fuselage) so that the surfaces exposed to the exterior atmosphere of the fuselage and the porthole can be in perfect continuity (outcrop) with each other. The porthole is generally maintained by flanges fixed on the mounting structure and exerting a force on the rear face of the porthole on the one hand, blocking by the element of the mounting structure opposite front (exterior) of the porthole on the other hand; the clamping clamps secure the porthole by pinching. On the other hand, the hybrid constitution of the first exterior slab in laminate of at least one transparent sheet of mineral glass and another transparent sheet of organic glass (polymer material) makes it possible to improve the Mass / Surface / Drag compromise of the window . In fact, the surface mass of a transparent polymer material such as poly(methyl methacrylate) (PMMA) is approximately 1.2/2.5 times that of mineral glass (twice as light at constant volume). On the other hand, the deflection of the first (external) slab is a function of its geometry divided by its equivalent stiffness E _eq , the equivalent stiffness is inversely proportional to the Young's modulus, that is to say that the equivalent stiffness PMMA is about 3/70 times that of mineral glass. The use of organic glass minimizes the weight of the porthole, the use of mineral glass minimizes sag and drag.

According to a first main variant, the first transparent sheet is made of organic glass and has stepped shaped edges forming a receiving cavity for an element of the mounting structure, the at least one second transparent sheet comprises at least one second sheet transparent sheet of mineral glass and optionally a third transparent sheet of organic glass or mineral glass, or a second transparent sheet of organic glass and a third transparent sheet of mineral glass.

According to a second main variant, the second transparent sheet is made of organic glass and has stepped shaped edges forming, with the edges of the first transparent sheet and the first adhesive layer, a reception cavity for an element of the structure of mounting, the first transparent sheet is either mineral glass or organic glass and the at least one second transparent sheet comprises a third transparent sheet of mineral glass.

Preferably, each sheet of mineral glass is made of soda-lime, aluminosilicate, borosilicate or similar glass, in particular floated, optionally hardened, thermally tempered or chemically reinforced, and has a thickness of between 0.5 and 6, preferably 2 and 4 mm.

Preferably, each sheet of organic glass is made of polymer material consisting of poly(methyl methacrylate) (PMMA), polycarbonate (PC), poly(ethylene terephthalate) (PET), polyurethane (PU) or the like, their mixtures or copolymers, and has a thickness of between 2 and 15, preferably 3 and 6 mm.

Preferably, each interlayer adhesive layer is made of polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), ionomer resin or casting resin, and has a thickness of between 0.3 and 6.0 , preferably 0.5 and 1.5 mm.

Preferably, the multiple glazing comprises materials of different densities, stiffnesses and damping, such as to give it an acoustic insulation property.

Preferably, the first transparent sheet covers the edge of the mounting joint facing outwards. This measure protects the silicone seal or equivalent.

Another object of the invention consists of the use of multiple glazing described previously as pressurized aircraft glazing, in particular passenger cabin window of a commercial aircraft. Such multiple glazing is able to be fixed by pinching to the cabin of a commercial aircraft, without any discontinuity of external surface between the glazing and the cabin (or fuselage), thanks to the profile of its edge presenting a reception cavity for an element of the mounting structure. On the other hand, the constitution of the first exterior slab of this multiple glazing in lamination of at least one sheet of mineral glass and at least one sheet of organic glass makes it possible to control the deflection and drag in flight (pressurized cabin), to prevent them from increasing fuel consumption, while limiting the weight of the multiple glazing.

The invention will be better understood in light of the following description of the appended drawings in which [Fig. 1 ], [Fig. 2] and [Fig. 3] schematically represent in section three embodiments of multiple glazing according to the invention.

With reference to Figure 1, double glazing according to the invention consists of a first transparent exterior slab 1, 2, 3 laminated and a second internal monolithic slab 7 maintained at a constant distance from the first slab by means of a waterproof peripheral seal 8 made of silicone, in which are embedded part of the edge of the first slab on the one hand, of the second slab on the other hand. The terms “exterior” and “interior” refer to the side of the exterior atmosphere on the one hand, and the interior volume delimited by the glazing, in particular of a vehicle such as a pressurized aircraft on the other hand.

The first exterior slab consists of a first sheet 1 of shaped PMMA 6 mm thick laminated to a second sheet 3 of chemically reinforced aluminosilicate glass (PMMA) 3 mm thick by means of an adhesive interlayer layer 2 of 2 mm thick thermoplastic polyurethane (TPU). The first sheet 1 of PMMA is shaped: it has a stepped profiled edge, with a recess on an outer fraction of 5 mm of the thickness of the first sheet 1, and an overhang on the fraction of 1 mm of this oriented thickness , in the mounting position, towards the interior volume of the aircraft.

The second slab 7 is made of a sheet of PMMA 3 mm thick. A peripheral silicone seal 8 maintains the first and second tiles at a distance of 8 mm from each other when at rest, so as to constitute an air gap 6. The second tile 7 or the seal 8 is provided (e) a small hole putting the air blade 6 into communication with the interior volume delimited by the double glazing, on the side of the second slab 7. Thus the air blade 6 is at the pressure of this interior volume, capable of being pressurized.

The stepped profiled edge of the first sheet 1 forms a cavity capable of accommodating an element of the mounting structure (to secure the double glazing by pinching to this mounting structure by means of clamping flanges against the rear face of the porthole) , with the interposition of the mounting joint 8, without discontinuity of the exterior surfaces of the mounting structure and the glazing. These two exterior surfaces are said to be flush with each other (in English: “flush”).

In flight, the pressurization of the passenger cabin forces the first slab 1, 2, 3 to bend from the inside out. The second sheet 3 of glass limits the deflection and the drag. In addition, the glass of the second transparent sheet 1, the TPU of the interlayer adhesive layer 2 and the PMMA of the first transparent sheet 1 are materials of different stiffness and damping, such as to give the first exterior slab a property of 'soundproofing. A thermal control, low-emissive reflective feature thermal radiation towards the inside of the delimited volume (commercial aircraft passenger cabin, etc.), or anti-solar reflecting solar radiation towards the outside, can be provided in different ways: composition of PMMA or TPU, stacking of layers thin solar protection on a sheet of glass or PMMA, as deposited by magnetron (magnetic field-assisted cathodic sputtering), or on a flexible polymer film (EVA or PET type) laminated or in adhesion on one side to the air of the double glazing, except on the side in contact with the outside atmosphere.

The double glazing shown in Figure 2 differs from that of Figure 1 in that the first slab comprises, from the outside to the inside, from top to bottom in the Figure, a first sheet 1 of chemically reinforced aluminosilicate glass 2 mm thick, a first adhesive layer 2 of TPU 2 mm thick, a second transparent sheet 3 of shaped PMMA 3 mm thick, a second adhesive layer 4 of TPU 2 mm thick and a third transparent sheet 5 of PMMA 3 mm thick. Here, it is the second transparent sheet 3 which is made of shaped PMMA, presenting a stepped edge with a recess of 1.5 mm from an outer fraction of the thickness of the sheet 3, and an overhang on the complementary fraction 1.5 mm of this thickness, towards the inside. In this configuration, it is the edges of the first transparent sheet 1 and the first adhesive layer 2 and the stepped edge of the shaped PMMA sheet 3 which form a reception cavity for an element of the mounting structure (not represented).

The glazing of Figure 3 differs from that of Figure 2 only in that the first glass sheet 1 covers the upper edge, oriented towards the exterior atmosphere in the mounting position, of the mounting seal 8, so as to protect the silicone seal 8. The double glazing of Figures 2 and 3, like that of Figure 1, allows flush mounting of the glazing relative to the fuselage of the aircraft, not shown. They also make it possible to limit the surface mass of the glazing by the use of transparent polymer material, as well as the deflection and drag in flight, by the use of mineral glass, when the interior volume of the aircraft is pressurized.

Claims

Claims 1. Multiple glazing to delimit two spaces with variable pressure difference, in particular an enclosure subjected to pressurization, comprising at least a first transparent slab (1; 2; 3; 4; 5) intended to be in contact with the exterior atmosphere in the mounting position, and separated from a second transparent slab (7) by an air gap (6), by means of a mounting joint (8) in which a peripheral part of the multiple glazing is embedded, characterized in that the first slab (1; 2; 3; 4; 5) is made up of a first transparent sheet (1) and at least two other transparent sheets (3; 5) glued two by two by an adhesive interlayer layer (2; 4), in that at least one of the first transparent sheet (1) and at least two other transparent sheets (3; 5) is made of mineral glass, and in that another of the first transparent sheet (1) and the second transparent sheet (3) is made of organic glass and has stepped shaped edges, the edges of an outer fraction of the thickness of this sheet (1 or 3) being recessed by relative to the edges of its internal complementary fraction, so as to form, where appropriate with the edges of the first sheet (1) and the first adhesive layer (2), a cavity for accommodating an element of the structure of assembly, with the interposition of the mounting joint (8). 2. Multiple glazing according to claim 1, characterized in that the first transparent sheet (1) is made of organic glass and has stepped shaped edges forming a reception cavity for an element of the mounting structure, in that the at least two other transparent sheets (3; 5) comprise at least a second transparent sheet (3) of mineral glass and a third transparent sheet (5) of organic glass or mineral glass, or a second transparent sheet (3) of glass organic and a third transparent sheet (5) of mineral glass. 3. Multiple glazing according to claim 1, characterized in that the second transparent sheet (3) is made of organic glass and has edges shaped in steps forming, with the edges of the first transparent sheet (1) and the first adhesive layer (2), a receiving cavity for an element of the mounting structure, in that the first transparent sheet (1) is made of mineral glass, or organic glass and the at least two other transparent sheets (3; 5) comprise a third transparent sheet (5) of mineral glass. 4. Multiple glazing according to one of the preceding claims, characterized in that each sheet of mineral glass is made of soda-lime, aluminosilicate, borosilicate glass, in particular floated glass, optionally hardened, thermally tempered or chemically reinforced, and has a thickness of between 0, 5 and 6, preferably 2 and 4 mm. 5. Multiple glazing according to one of the preceding claims, characterized in that each sheet of organic glass is made of polymer material consisting of poly(methyl methacrylate) (PMMA), polycarbonate (PC), poly(ethylene terephthalate) ( PET), polyurethane (PU), their mixtures or copolymers, and has a thickness between 2 and 15, preferably 3 and 6 mm. 6. Multiple glazing according to one of the preceding claims, characterized in that each interlayer adhesive layer is made of polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), ionomer resin or casting resin, and has a thickness of between 0.3 and 6.0, preferably 0.5 and 1.5 mm. 7. Multiple glazing according to one of the preceding claims, characterized in that it comprises materials of different densities, stiffnesses and damping, such as to give it an acoustic insulation property. 8. Multiple glazing according to one of the preceding claims, characterized in that the first transparent sheet (1) covers the edge of the joint (8) facing outwards. 9. Use of multiple glazing according to one of the preceding claims as pressurized aircraft glazing, in particular commercial aircraft passenger cabin window.