Hybrid flush porthole with improved balance between mass, surface and resistance
Through the design of multi-layer glass window units, the combination of mineral and plexiglass sheets is used to solve the problem of aircraft portholes sag under pressure, achieving lightweight and low drag aerodynamic effects.
Patent Information
- Application Number
- CN202480008565.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-01-23
- Filing Date
- 2024-01-11
- Publication Date
- 2025-08-29
AI Technical Summary
Existing aircraft portholes are prone to sag due to pressurization during flight, resulting in increased aerodynamic drag, fuel consumption, and weight increase.
The multi-layered glass window unit, including a combination of mineral glass and plexiglass sheets, is connected by a viscous mezzanine, and the cavity is designed on the exterior surface to be flush with the fuselage, and is maintained with clamping rings to reduce weight and control deflection and resistance.
It achieves the aerodynamic continuity between the aircraft porthole and the fuselage while reducing weight, reduces aerodynamic drag and reduces fuel consumption.
Smart Images
Figure CN120569327A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a lightweight, low-drag aircraft window, that is to say a window which, under the effect of the pressurization of the aircraft's internal volume during flight, does not deform by forming a protrusion (droop) relative to the surrounding aircraft fuselage, which protrusion (droop) would be detrimental from an aerodynamic point of view and in terms of energy consumption for propelling the aircraft. Background Art
[0002] This applies in particular to windows with two panels separated by an air gap. Such double-panel aircraft windows are made of polymethyl methacrylate (PMMA). In the event of a failure of the outer panel, the inner panel would maintain the aircraft's internal volume at the desired pressure. Even though the inner panel (or the peripheral gasket in contact with it) is usually provided with a small through-hole in order to maintain the air gap at the pressure of the aircraft's internal volume during flight under normal conditions, in the event of a rupture of the outer panel, this inner panel would be able to maintain the aircraft's internal volume at the desired pressure during flight because the hole is small enough to maintain the minimum air flow compensated by the aircraft's air conditioning unit; in this case, a whistling sound may be generated.
[0003] More specifically, the present invention aims to provide such a window that is aerodynamically continuous with the fuselage and has a mixed composition (mineral-organic) to improve the mass / surface / drag compromise. Aerodynamic continuity means that the outer surface of the window is perfectly continuous with that of the fuselage, i.e. there are no irregularities, protrusions or recesses between the two surfaces. However, the added weight of the window results in a loss of aircraft range and an increase in aerodynamic drag. Increasing the surface area of the window results in an increase in drag at constant weight, or an increase in weight at constant deflection. Summary of the Invention
[0004] This object is achieved by the present invention, which relates to a multi-layer glazing unit for delimiting two spaces with a variable pressure difference, in particular a housing subjected to pressure, the multi-layer glazing unit comprising at least one first transparent panel intended to be in contact with the external atmosphere in the mounted position and separated from a second transparent panel by an air gap by means of a mounting gasket, in which the peripheral portion of the multi-layer glazing unit is embedded, characterized in that the first panel consists of a first transparent sheet and at least one second transparent sheet bonded in pairs by an adhesive interlayer, wherein at least one of the first transparent sheet and the at least one second transparent sheet is made of mineral glass and the other is made of organic glass, and wherein the edges of the first transparent sheet are set back relative to the edges of the at least one second transparent sheet, so that the edges of the first transparent sheet and of the first adhesive interlayer, as well as the free part of the main surface of the second transparent sheet projecting beyond the first transparent sheet, form a cavity for receiving an element of the mounting structure, with the gasket positioned between them.
[0005] The shape of the edge of the porthole on the side facing the external atmosphere comprises a cavity corresponding to the opening made in the mounting structure (fuselage), so that the surfaces of the fuselage and the porthole exposed to the external atmosphere are perfectly continuous (flush) with each other. The porthole is generally held in place by a clamping ring attached to the mounting structure and which, on the one hand, exerts a force on the back of the porthole and, on the other hand, is locked to the front (external) face of the porthole by means of an element of the mounting structure; the clamping ring secures the porthole by clamping. Furthermore, the hybrid structure of the first outer laminated panel of at least one transparent inorganic glass sheet and another transparent organic glass (polymer material) sheet improves the compromise of mass / surface / resistance of the porthole. In fact, the mass per unit area of a transparent polymer material such as polymethyl methacrylate (PMMA) is approximately 1.2 / 2.5 times that of a mineral glass (twice as light at constant volume). Furthermore, the deflection of the first (external) panel is the product of its geometry divided by its equivalent stiffness E eq The equivalent stiffness is inversely proportional to Young's modulus, meaning that the equivalent stiffness of PMMA is approximately 3 / 70 of that of mineral glass. Using PMMA minimizes the weight of the porthole, while using mineral glass minimizes sagging and drag.
[0006] According to a first main variant, the first transparent sheet is made of mineral glass and the at least one second transparent sheet comprises at least one second transparent sheet made of organic glass and optionally a third transparent glass sheet made of mineral glass or organic glass, or a second transparent glass sheet made of mineral glass and a third transparent glass sheet made of organic glass.
[0007] According to a second main variant, the first transparent sheet is made of organic glass and the at least one second transparent sheet comprises at least one second transparent sheet made of mineral glass and optionally a third transparent glass sheet made of mineral glass or organic glass, or a second transparent glass sheet made of organic glass and a third transparent glass sheet made of mineral glass.
[0008] Preferably, each mineral glass sheet is made of soda-lime glass, aluminosilicate, borosilicate or similar, in particular float glass, possibly hardened, thermally tempered or chemically strengthened, and has a thickness between 0.5 and 6 mm, preferably between 2 and 4 mm.
[0009] Preferably, each organic glass sheet is made of a polymer material consisting of polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyurethane (PU) or the like, a mixture or copolymer thereof, and has a thickness between 2 and 15 mm, preferably between 3 and 6 mm.
[0010] Preferably, each adhesive interlayer is made of polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), ionomer resin or casting resin and has a thickness between 0.3 and 6.0 mm, preferably between 0.5 and 1.5 mm.
[0011] Preferably, the multiple glazing unit comprises materials having different densities, stiffness and damping properties to provide sound insulation.
[0012] Another object of the present invention is the use of a multi-layer glazing unit as described above as a glazing unit for pressurized aircraft, in particular for cabin windows of commercial aircraft. This multi-layer glazing unit can be clamped onto the fuselage of a commercial aircraft without any discontinuity in the outer surface between the glazing unit and the fuselage, since the contours of the edges of the multi-layer glazing unit present cavities for receiving elements of the mounting structure. Furthermore, the first outer panel of the multi-layer glazing unit is composed of at least one sheet of inorganic glass and at least one sheet of organic glass, which helps to control deflection and drag in flight (in a pressurized cabin) so that they do not affect fuel consumption while limiting the weight of the multi-layer glazing unit. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will be better understood with reference to the following description of the accompanying drawings, in which Figure 1 、 Figure 2 and Figure 3 Three embodiments of multiple glazing units according to the invention are shown schematically in cross section. DETAILED DESCRIPTION
[0014] See also Figure 1 , a double glazing unit according to the invention consists of a first laminated outer transparent panel 1, 2, 3 and a second monolithic inner panel 7 which is kept at a constant distance from the first panel by means of a peripheral silicone gasket 8, wherein the edge portions of the first panel on the one hand and of the second panel on the other hand are embedded in the peripheral silicone gasket 8. The terms "outer" and "inner" refer, on the one hand, to the external atmospheric side and, on the other hand, to the internal volume delimited by the glazing, in particular the glazing of a vehicle such as a pressurized aircraft.
[0015] The first outer panel consists of a first sheet 1 of chemically strengthened aluminosilicate glass 5 mm thick laminated to a second sheet 3 of polymethyl methacrylate (PMMA) 4 mm thick by means of an adhesive interlayer 2 of thermoplastic polyurethane (TPU) 2 mm thick.
[0016] The second panel 7 consists of a PMMA1 sheet with a thickness of 3 mm. A peripheral silicone gasket 8 holds the first and second panels at a static distance of 8 mm from each other, thereby forming an air gap 6. The second panel 7 or gasket 8 is provided with a small hole that connects the air space 6 with the internal volume of the double-glazed window defined on the side of the second panel 7. The air gap 6 is therefore at the pressure of this pressurizable internal volume.
[0017] The edges of the first sheet of glass 1 are set back from the edges of the second PMMA sheet 3 and the second panel 7. The edges of the first sheet of glass 1 and of the TPU adhesive layer 2, as well as the peripheral surface of the second PMMA sheet 3 that protrudes beyond the first sheet 1, form a cavity capable of accommodating the elements of a mounting structure (for clamping the double-glazed window to this mounting structure by means of a clamping ring against the back of the porthole), with the mounting gasket 8 positioned therebetween, without interruption between the mounting structure and the outer surface of the glazing unit. These two outer surfaces are said to be flush with one another.
[0018] During flight, cabin pressurization causes the first panels 1, 2, and 3 to flex from the inside out. The first glass sheet 1 limits deflection and drag. Furthermore, the glass of the first transparent sheet 1, the TPU of the adhesive interlayer 2, and the PMMA of the second transparent sheet 3 are all materials with different stiffness and damping properties to impart acoustic insulation to the first outer panel. Thermal control, whether a low-e function that reflects thermal radiation into a defined volume (e.g., the passenger cabin of a commercial aircraft) or a sunscreen function that reflects solar radiation outward, can be provided in a variety of ways: as a component of the PMMA or TPU; as a thin sunscreen layer stacked on the glass or PMMA sheet, deposited by magnetron (magnetic field assisted sputtering); or as a flexible polymer film laminated or bonded to one side of the double-glazed window unit (except the side in contact with the outside atmosphere).
[0019] Figure 2 Double glazed window units shown in Figure 1 The double glazing unit of FIG. 5 differs in that a third sheet 5 of 1 mm thick chemically strengthened aluminosilicate glass is added to the first panel, bonded to a second sheet 3 of 3 mm thick PMMA via a 1 mm thick TPU adhesive layer 4. The first sheet 1 of chemically strengthened aluminosilicate glass is 4 mm thick.
[0020] and Figure 2 Similar to the double glazed window units in Figure 3 The double glazing unit in FIG also has a first sheet 1 of 4 mm thick chemically strengthened aluminosilicate glass, a 2 mm thick adhesive interlayer 2 of thermoplastic polyurethane (TPU), and a 1 mm thick adhesive layer 4 of TPU. On the other hand, the 3 mm thick second transparent sheet 3 is made of glass instead of PMMA, and the 1 mm thick third transparent sheet 5 is made of PMMA instead of glass. Figure 1Similar to what is shown in Figure 2 and Figure 3 The double-glazed window unit shown in FIG allows the glazing unit to be mounted flush with the aircraft fuselage (not shown). The use of a transparent polymer material also limits the mass per unit area of the glazing unit, while the use of mineral glass reduces in-flight deflection and drag when the aircraft's interior volume is pressurized.
Claims
1. A multi-glazing unit for delimiting two spaces with a variable pressure difference, in particular a housing subjected to pressurization, comprising at least one first transparent panel (1; 2; 3; 4; 5) intended to be in contact with the external atmosphere in the mounted position and separated from a second transparent panel (7) by an air gap (6) by means of a mounting gasket (8), in which the peripheral portion of the multi-glazing unit is embedded, characterized in that The first panel (1; 2; 3; 4; 5) is composed of a first transparent sheet (1) and at least two other transparent sheets (3; 5), wherein the first transparent sheet (1) and at least one of the at least two other transparent sheets (3; 5) are made of mineral glass, and the other is made of organic glass, and wherein the edge of the first transparent sheet (1) is set back relative to the edges of the at least two other transparent sheets (3; 5), so that the edges of the first transparent sheet (1) and the first adhesive interlayer (2), and the free part of the main surface of the second transparent sheet (3) protruding outside the first transparent sheet (1) form a cavity for receiving the elements of the mounting structure, and the mounting gasket (8) is located between the edges of the first transparent sheet (1) and the first adhesive interlayer (2) and the free part of the main surface of the second transparent sheet (3).
2. The multi-glazing unit according to claim 1, wherein The first transparent sheet (1) is made of mineral glass, and the at least two other transparent sheets (3; 5) include at least a second transparent sheet (3) made of organic glass and a third transparent glass sheet (5) made of mineral glass or organic glass, or a second transparent glass sheet (3) made of mineral glass and a third transparent glass sheet (5) made of organic glass.
3. The multi-glazing unit according to claim 1, wherein The first transparent sheet (1) is made of organic glass, and the at least two other transparent sheets (3; 5) include at least a second transparent sheet (3) made of mineral glass and a third transparent glass sheet (5) made of mineral glass or organic glass, or a second transparent glass sheet (3) made of organic glass and a third transparent glass sheet (5) made of mineral glass.
4. Multiple glazing unit according to one of the preceding claims, characterized in that Each mineral glass sheet is made of soda-lime glass, aluminosilicate glass, borosilicate glass, in particular float glass, optionally hardened, thermally tempered or chemically strengthened, and has a thickness between 0.5 and 6 mm, preferably between 2 and 4 mm.
5. Multiple glazing unit according to one of the preceding claims, characterized in that Each organic glass sheet is made of a polymer material including polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyurethane (PU), mixtures or copolymers thereof, and has a thickness between 2 and 15 mm, preferably between 3 and 6 mm.
6. Multiple glazing unit according to one of the preceding claims, characterized in that Each adhesive interlayer is made of polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), thermoplastic polyurethane (TPU), ionomer resin or casting resin and has a thickness between 0.3 and 6.0 mm, preferably between 0.5 and 1.5 mm.
7. Multiple glazing unit according to one of the preceding claims, characterized in that It includes materials with different densities, stiffness and damping properties to impart sound insulation properties.
8. Use of a multi-layer glazing unit according to one of the preceding claims as a pressurized aircraft glazing unit, in particular a cabin window for commercial aircraft.