INSULATING GLAZING WITH LOW-POWER HEATING AND HIGH MECHANICAL STRENGTH

Abstract

An insulated glazing unit includes a first laminated pane including two glass sheets, each no more than 2 mm thick, that are bonded to one another by an intermediate adhesive layer, a second structural laminated pane providing the mechanical strength required for the flight conditions of an airplane, in particular resistance to bird strike and control of glazing unit deformation under pressure difference conditions during a flight on either side of the insulated glazing unit, and a gas gap between the first and second laminated panes, the first laminated pane being provided with a heating system.

Claims

1. An insulated glazing unit comprising a first laminated pane comprising two glass sheets, each no more than 2 mm thick, that are bonded to one another by an intermediate adhesive layer, a second structural laminated pane providing mechanical strength required for flight conditions, including a resistance to bird strike and control of glazing unit deformation under pressure difference conditions during a flight on either side of the insulated glazing unit, and a gas gap between the first laminated pane and the second structural laminated panes, the first laminated pane being provided with a heating system.

2. The insulated glazing unit as claimed in claim 1, wherein the first laminated pane and the second structural laminated pane are held together by a spacer to form the gas gap between the first laminated pane and the second structural laminated panes.

3. The insulated glazing unit as claimed in claim 1, wherein the second structural laminated pane has at least one glass sheet at least 4 mm thick, laminated on either side to a first glass sheet by means of an intermediate adhesive layer and to a second glass sheet by means of an intermediate adhesive layer.

4. The insulated glazing unit as claimed in claim 1, wherein each of the two glass sheets forming the first laminated pane is at most 1.5 mm thick.

5. The insulated glazing unit as claimed in claim 1, wherein the heating system is a tin-doped indium oxide electrically conductive layer.

6. The insulated glazing unit as claimed in claim 1, wherein the glass sheets forming said glazing unit are made of soda-lime, aluminosilicate or borosilicate glass, optionally tempered thermally or chemically, or of a transparent polymer material.

7. The insulated glazing unit as claimed in claim 1, wherein each intermediate adhesive layers of said glazing unit is made of polyvinyl butyral (PVB), thermoplastic polyurethane (TPU), or ethylene-vinyl acetate (EVA), optionally multilayer to provide sound damping.

8. The insulated glazing unit as claimed in claim 1, wherein the air gap is hermetically and sealingly separated from a volume outside the insulated glazing unit on the side of the first laminated pane by a flexible inflatable membrane.

9. A method comprising manufacturing an aircraft glazing unit with the insulated glazing unit as claimed in claim 1, the first laminated pane being oriented towards an internal volume of the aircraft and the second structural laminated pane being oriented towards an outside atmosphere.

10. The method as claimed in claim 9, wherein the aircraft glazing unit is an airplane cockpit lateral glazing unit.

11. The insulated glazing unit as claimed in claim 2, wherein the spacer is a frame-shaped spacer.

12. The insulated glazing unit as claimed in claim 4, wherein each of the two glass sheets forming the first laminated pane is at most 1 mm thick.

13. The insulated glazing unit as claimed in claim 12, wherein each of the two glass sheets forming the first laminated pane is at most 0.8 mm thick.

14. The insulated glazing unit as claimed in claim 6, wherein the transparent polymer material is poly (methyl methacrylate) (PMMA), polycarbonate (PC), polyurethane or polyurea (PU).

Description

[0027] A specific embodiment is described below with reference to the attached drawing to better illustrate the subject matter of the present invention.

[0028] In this drawing:

[0029] FIG. 1 shows a schematic cross-section view of an insulated glazing unit according to the present invention.

[0030] FIG. 1 shows an insulated glazing unit according to one embodiment of the invention.

[0031] The insulated glazing unit is formed by assembling a first laminated pane 1 and a second structural laminated pane 2, separated by a cavity 4 that is 2 mm thick and that contains air.

[0032] The first laminated pane 1 is made of two monolithic glass sheets 11, 13 that are 0.5 mm thick and that are separated by an intermediate adhesive layer 12 that is 0.38 mm thick.

[0033] The free surface of the glass sheet 13 facing the second structural laminated pane 2 bears a conductive layer made of five-ohms-per-square tin-doped indium oxide (ITO) to provide low-emissivity infrared-radiation reflection and heating functions.

[0034] From the air gap 4 towards the free surface of the insulated glazing unit, the second structural laminated pane 2 is made up of a glass sheet 21 that is 3 mm thick bonded to a glass sheet 23 that is 8 mm thick by an intermediate adhesive layer 22 that is 2 mm thick, and a glass sheet 25 that is 3 mm thick bonded to the glass sheet 23 by an intermediate adhesive layer 24 that is 3 mm thick.

[0035] The first and second laminated panes 1, 2 are held together with a 2 mm space such as to form the air gap 4 using a spacer frame 3.

[0036] All of the glass sheets are chemically or thermally tempered aluminosilicate or soda-lime glass sheets. The intermediate adhesive layers are thermoplastic polyurethane (TPU) or polyvinyl butyral (PVB) layers, possibly multilayer such as to provide sound damping.

[0037] The height and width of the insulated glazing unit is in the order of 60 cm.

[0038] Where the insulated glazing unit is assembled as a lateral glazing unit of an airplane cockpit, the first laminated pane 1 is oriented towards the cockpit and the second laminated pane 2 is in contact with the outside atmosphere.

[0039] In the following conditions: internal convection of 7 W/m.sup.2/° C. and air at 20° C. external convection of 110 W/m.sup.2/° C. and air −50° C., the proposed solution enables an internal skin temperature (free surface of the glass sheet 11=internal face of the insulated glazing unit) of 11° C. to be maintained with a power of 500 W/m.sup.2, while 2300 W is required in the absence of (insulated) double glazing with heating on the outer face of the middle Glass in conventional laminated panes (i.e. the second glass sheet from the outside).

[0040] The lower power is compatible with a 28 V power supply (standard).

[0041] The low power can obviate the need for control sensors (cause of failure).

[0042] This system improves the reparability of the heating portion of the glazing unit.

[0043] The mechanical plies are also protected from scratching that could cause the glazing unit to break.

[0044] By reflecting infrared radiation, the low-emission function of the ITO heating layer 14 keeps the heat inside the airplane.