GB2485369A

GB2485369A - Window edge assembly

Info

Publication number: GB2485369A
Application number: GB1019056.9A
Authority: GB
Inventors: Ian Charles Howlett
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-11-11
Filing date: 2010-11-11
Publication date: 2012-05-16
Also published as: GB201019056D0

Abstract

A glazing unit comprises at least two glazing sheets 12 a spacer 16 disposed between the glazing sheets and forming a channel between the edges of the glazing sheets; and a filler/bonder 20, for example of hot-melt adhesive, disposed in the channel and bonded to the glazing sheets and spacer to hold them together and a vapour barrier layer 24 of a material which is impervious to water vapour which extends around and is bonded to the outer edge of the glazing unit and covers the outer edge of the filler/bonder. The vapour barrier may be an adhesive tape, preferably a metallic tape, for example copper tape, aluminium tape or lead tape, or an alloy tape of those three metallic elements. A method of manufacture is also claimed. The arrangement may be use for triple glazing or more with a separate spacer and bonder and a single vapour barrier.

Description

TITLE

Multiple-glazing units

DESCRIPTION

This invention relates to multiple-glazing units, i.e. glazing units in which two or more glazing sheets (e.g. glass sheets) are spaced apart such that there is a heat-insulating gap between the glazing sheets. Such glazing units may be used, for example, in windows and doors.

S Double-glazing units are well known. In a conventional construction of double-glazing unit, two rectangular sheets of glass are spaced apart by a rectangular frame which is inset slightly from the edges of the sheets of glass so that a channel is formed around the frame and between the sheets. The channel is then filled with a hot-melt adhesive or other flexible bonding compound which bonds to both the sheets and the spacer so as to hold the glass sheets and spacer together and to seal the space which is within the frame and between the glass sheets.

The space contains air or other gas such as argon. In this case, the gas is preferably dry (i.e. does not contain any water vapour), so that water will not condense on the inside glass surface and fog-up the glazing unit. The spacer may also be provided with a desiccating function to absorb any moisture in the space.

A problem with such known glazing units is that the seal may be slightly permeable to air and water vapour, for example because of the inherent permeability of the material of the seal, or due to a flaw in the bonding of the material to the glass sheets. With fluctuations in atmospheric pressure and the temperature to either side of the glazing unit, the pressure difference across the seal can vary significantly and may be sufficient to cause the seal to start leaking. If the seal is, or does become, permeable and cannot maintain any significant pressure difference between the space and the ambient atmosphere, the mass of air and water vapour in the space can vary greatly with variations in atmospheric pressure and the temperature in the space. For example, to a first-order gas law approximation, for a pressure increase from, say, 0.96 atm to 1.04 atm and a temperature drop from, say, 25 C to -S C at constant humidity, the increase in the mass of air and water vapour in the space between the glass plates increases by filOO x 1.04 x (273 +25)1 / 110.96 x (273-S)I} -100 = 20%. In time, water molecules may therefore enter the space, and, at least in some weather conditions, they may condense on the inner face of one or both glass sheets and cause the glazing unit to fog up. Even if the spacer has a desiccating function, there is a limit to how much water can be absorbed. Some double-glazing units may last for many years, but others may fog-up and fail far sooner and even in less than a year.

An aim of the present invention, or at least of specific embodiments of it, is to reduce the tendency of multiple glazing units to fog up and to do so in a simple and inexpensive manner.

In accordance with a first aspect of the present invention, there is provided a glazing unit comprising, as is known: at least two glazing sheets (for example glass sheets) arranged parallel to, and spaced apart from, each other; a spacer disposed between said two glazing sheets, extending along the edge of each sheet (for example in the case of circular glazing sheets) or each edge of each sheet (for example in the case of rectangular glazing sheets) and inset from the edge(s) so that a channel is formed between the edges of the glazing sheets; and a filler/bonder disposed in the channel and bonded to said two glazing sheets and the spacer to hold said two glazing sheets and spacer together. The glazing unit of the first aspect of the invention is characterised in that a vapour barrier layer of a material which is impervious to water vapour extends around and is bonded to the or each outer edge of the glazing unit and covers the or each outer edge of the filler/bonder. The invention therefore enables glazing units to be constructed in the conventional fashion, except for the addition of the vapour barrier which prevents water molecules from entering the main space between the glazing sheets.

The vapour barrier layer may be bonded to the or each outer edge of the filler/bonder.

Additionally or alternatively, the vapour barrier layer may be bonded to the or each side edge of each of the glazing sheets.

The invention is applicable to a double-glazing unit in which there are only two such glazing sheets, each of which has an exposed outer face. The invention is also applicable to multiple-glazing units in which there are more than two such glazing sheets. In this latter case: such a spacer is preferably disposed between each adjacent pair of the glazing sheets so that such a channel is formed at the edges of each adjacent pair of the glazing sheets; such a filler/bonder is preferably disposed in each channel; and the outermost two glazing sheets each have an exposed outer face.

In either case, the vapour barrier may also extend over the or each marginal edge of each exposed outer face and is bonded thereto. Firstly, this reduces the risk that the vapour barrier might be dislodged during handling and fitting of the glazing unit. Secondly, the vapour barrier covers any sharp edges of the glazing sheets and reduces the risk of injury during handling. Thirdly, this increases the bonding distance from the ambient atmosphere to the inside of the glazing unit.

As is conventional, the glazing unit may be fitted to a frame having a channel receiving the or each edge of the glazing unit and a frame seal which engages with the marginal edge(s) of at least one outer face of the glazing unit. In this case, the frame seal may engage with the vapour barrier, so that the frame seal assists in pressing the vapour barrier against the glazing sheet, thereby assisting in maintaining the bond between the glazing sheet and the vapour barrier. Alternatively, the vapour barrier may stop short of the frame seal.

The vapour barrier is preferably in the form of a tape. Preferably, the tape is bonded to the glazing sheets and/or filler/bonder by adhesive.

Preferably, the vapour barrier comprises a metal, more preferably a ductile metal, and more preferably copper, aluminium, lead or an alloy including copper, aluminium or lead. The metal preferably has a thickness not exceeding 0.25 mm, and in some embodiments not exceeding 0.05 mm.

In a preferred embodiment, the vapour barrier is provided by self-adhesive copper tape.

In accordance with a second aspect of the present invention, there is provided a method of manufacture of a glazing unit. As is conventional, the method comprises the steps of: disposing a spacer between two glazing sheets so that the glazing sheets are arranged parallel to, and spaced apart from, each other, and so that the spacer extends along the or each edge of each sheet, inset from the edge(s) so that a channel is formed at the edges of the glazing sheets; and then inserting a filler/bonder into the channel and allowing the filler/bonder to bond to the glazing sheets and the spacer to hold the glazing sheets and spacer together. The method is characterised by the step of then bonding a vapour barrier which is impervious to water vapour to the or each outer edge of the glazing unit so that the vapour barrier extends around the or each edge of the glazing unit and covers the or each outer edge of the filler/bonder.

The method may be performed so as to manufacture a glazing unit having any of the preferred features, described above, of the glazing unit of the first aspect of the invention.

Specific embodiments of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: Figures 1A-7B are views at different stages in the construction of the a double-glazing unit, with the figure numbers having an A' suffix being isometric views, and the figure numbers having a B' suffix being sectioned views, on a larger scale, of an edge portion of the glazing unit; and Figure 8 is similar to Figure 7B, but instead showing a triple-glazing unit.

In the drawings, edges which can be seen through glass are shown in dashed lines.

Referring to Figures 1A to 3B of the drawings, a double-glazing unit 10 is constructed from two identical rectangular glass sheets 12 and a spacer 16 in the form of a rectangular frame, as shown in Figures 1A & 2B. The spacer 16 may be formed from a single member, or four member joined at the corners. It may be of plastics material or a thin aluminium extrusion.

The external height h and breadth b of the spacer are slightly less than the height II and breadth B, respectively, of each glass sheet 12. The glass sheets 12 and spacer 16 are placed in a jig with the spacer 16 sandwiched between the glass sheets 12, SO that, as shown in Figures 2A & 2B, a channel 18 of approximately uniform depth d is formed around the spacer 16 and between the sheets 12. The channel 18 is then filled with holt-melt adhesive which, when cooled, bonds to the glass sheets 12 and spacer 16 to form a seal 20, as shown in Figures 3A & 3B, separating the spacer 16 and the space 22 within the spacer 16 and between the glass sheets 12 from the surrounding atmosphere. The above operation may be performed in a dry air or argon atmosphere, so that the space 22 contains dry air or dry argon, and the spacer 16 may contain a desiccating agent in an attempt to keep the space 22 free of water vapour which, in use, might condense on the inner faces of the glass sheets 12.

The double-glazing unit 10 as described so far in the preceding paragraph, and its method of manufacture, are conventional. In the embodiment of the invention, a vapour barrier is subsequently applied, as will now be described with further reference to Figures 4A-7B.

The vapour barrier is formed from a length of copper tape 24 which has a waterproof, pressure-sensitive adhesive coating 26 on one side. The copper tape has a width W (see Figure 4A) which is substantially wider than the thickness T (see Figure 3A) of the glazing unit 10. A length of the copper tape 24, slightly longer than the perimeter length 2H + 2B of the glazing unit 10, is wound with its adhesive side inwards around the perimeter of the glazing unit 10, as shown in Figures 4A & B, and adheres to the edges of the glass sheets 12. The ends 27 of the copper tape 24 overlap and adhere to each other.

Along two opposite edges 28 of the glazing unit 10, the copper tape 24 is then folded against the marginal edges of the outer faces of the glass sheets 12, as shown in Figures 5A & B, and neat folded pleats are formed at the corners 30 of the glazing unit 10. Along the other two opposite edges 32 of the glazing unit 10, the copper tape 24 is then folded against the marginal edges of the outer faces of the glass sheets 12, as shown in Figure 6A, and the copper tape 24 is pressed firmly against the edges of the glass sheets 12, the marginal edges of the outer faces of the glass sheets 12 and the outer edge of the seal 20.

A suitable self-adhesive copper tape 24 is available from Venture Tape Corp, of Rocidand, MA 02370, USA and sold under the trade mark VentureTape® 1650. The copper of that tape has high tensile strength, zero temper and is malleable so that it can conform to the surface to which it adheres. The copper has a thickness of about 0.038 mm. The adhesive backing is acrylic based, highly aggressive and also has a thickness of about 0.038 mm. The tape is conveniently supplied in rolls with a release liner covering the adhesive backing.

Once the copper tape 24 has been applied to the glazing unit 10 to form the vapour barrier, the glazing unit 10 may be fitted to, for example, a conventional window frame 34 to form a window 36, as shown in Figures 7A & B. Any conventional design of window frame may be employed. In Figures 7A & B, the frame 34 has frame members 36, packing elements 38 and elastomeric seals 40 which bear against the marginal edges of the outer faces of the glazing unit 10. As shown in particular in Figure 7B, the distance D (equal approximately to zW -zT) by which the copper tape 24 overlaps the marginal edges of the outer faces of the glazing unit 10 may be sufficiently great that the frame seals 40 bear on the copper tape 24 and assist in pressing the copper tape 24 against the glass sheets 12, thereby assisting in maintaining the bond between the glass sheets 12 and the adhesive coating 26 on the copper tape 24.

Alternatively, the distance D may be sufficiently small that the copper tape 24 stops short of the frame seals 40, and the frame seals 40 bear directly on the glass sheets 12.

It will be appreciated that, at the temperatures and pressures to which glazing units 10 are usually exposed, the copper tape 24 is completely impervious to water and water vapour, i.e. water and water vapour cannot pass through the copper tape 24 from one face to the other.

The tape 24 can be applied so that its thin adhesive coating 26 is in intimate contact with the side edges of the glass sheets. At the corners of the side edges of the glass sheets 12, the copper tape 24 is sufficiently thin and malleable that it can be creased very sharply to maintain the intimate contact with the glass sheets 12. At the overlapping ends 27 of the copper tape 24, the total thickness of the tape 24 and adhesive coating 26 is sufficiently thin and the copper is sufficiently malleable that intimate contact can be maintained. The self-adhesive copper tape 24, by virtue of its bonding to the side edges of the glass sheets 12 and its bridging of the space between the side edges of the two glass sheets 12, therefore forms a vapour barrier between the space 22 between the glass sheets 12 and the ambient atmosphere.

Furthermore, it will be noted that the marginal edges of the copper tape 24 are folded over the marginal edges of the outer faces of the glass sheets 12 and bonded thereto by the adhesive coating 26. Firstly, this reduces the risk that the copper tape 24 might be dislodged during handling and fitting of the glazing unit 10. Secondly, the copper tape 24 covers any sharp edges of the glass sheets 12 and reduces the risk of injury during handling. Thirdly, this increases the bonding distance from the ambient atmosphere to the inside of the glazing unit 10.

Therefore, in the event that the thin adhesive coating 26 has a very slight permeability to water vapour in the direction at right angles to its thickness, the distance that the water molecules would need to travel through the adhesive is substantially increased so that the leakage rate becomes insignificant.

Although it has been found that a self-adhesive copper tape 24 having the characteristics described above is very rugged, in the event that the tape 24 does become damaged prior to or during installation, it can simply be patched with further small pieces of the copper tape 24.

It will be appreciated that many modifications and developments may be made to the embodiment of the invention described above.

For example, the invention may be applied to glazing units having more than two glazing sheets. Figure 8 shows an example of a triple-glazed unit 10 having a central glass sheet 14 between the outer glass sheets 12. The central sheet 14 is spaced from each outer sheet 12 by a respective spacer 16, and a respective seal 20 of hot-melt adhesive bonds a respective outer sheet 12, the central sheet 14 a respective spacer 16 together. In cross-section, the self-adhesive copper tape 24 extends from the marginal edge of the outer face of one of the glass sheets 12 to the marginal edge of the outer face of the other glass sheet 12 and is bonded by the adhesive coating 26 also to the side edge of the central glass sheet 14.

Although it is preferred that the copper tape 24 is self-adhesive, the copper tape 24 may be bonded to the glass sheets 12 in other ways, for example using a separate double-sided adhesive tape, or by using a flowable adhesive.

Metals other than copper may be used for the tape 24, for example aluminium or lead, or alloys of copper, aluminium or lead. Also, plastics tapes which are impervious to water and water vapour and are sufficiently malleable may be employed. Moreover, a laminated tape may be employed, for example, a laminated tape available from Venture Tape Corp, of Rockland, MA 02370, USA and sold under the trade mark VentureFlash® VF800. That tape is a three-ply laminate of two outer aluminium layers and a polyester core layer, coated on one face with a pressure-sensitive acrylic adhesive and having a total thickness of about 0.19 mm.

Rather than applying the vapour barrier as a tape 24, it may be applied in other ways, for example by metal spraying.

Although the tape 24 has been described above as being folded over the marginal edges of the outer faces of the outer glass sheets 12, a narrower tape 24 may be employed having a width W approximately equal to the thickness T of the glazing unit 10 so that the tape 24 only covers the edges of the glass sheets 12,14 and the outer surface of the seal 20. Moreover, an even less wide tape 24 may be employed having a width W approximately equal to the spacing between the glass sheets 12,14, so that the tape 24 is applied only to the outer surface of the seal 20.

Although a rectangular glazing unit 10 having four edges has been described above, the invention is applicable to other shapes of glazing units including, for example, circular or elliptical glazing units having only one edge.

It should be noted that the embodiments of the invention have been described above purely by way of example and that many other modifications and developments may be made thereto within the scope of the present invention.

Claims

CLAIMS1. A glazing unit comprising: at least two glazing sheets arranged parallel to, and spaced apart from, each other; a spacer disposed between said two glazing sheets, extending along the or each edge of the sheets and inset from the edge(s) so that a channel is formed between the edges of the glazing sheets; a filler/bonder disposed in the channel and bonded to said two glazing sheets and the spacer to hold said two glazing sheets and spacer together; and a vapour barrier layer of a material which is impervious to water vapour extending around and bonded to the or each outer edge of the glazing unit and covering the or each outer edge of the filler/bonder.
2. A glazing unit as claimed in claim 1, wherein: the vapour barrier layer is bonded to the or each outer edge of the filler/bonder.
3. A glazing unit as claimed in claim 1 or 2, wherein: the vapour barrier layer is bonded to the or each side edge of each of the glazing sheets.
4. A glazing unit as claimed in any preceding claim, wherein: there are only two such glazing sheets, each of which has an exposed outer face.
5. A glazing unit as claimed in any of claims 1 to 3, wherein: there are more than two such glazing sheets; such a spacer is disposed between each adjacent pair of the glazing sheets so that such a channel is formed at the edges of each adjacent pair of the glazing sheets; such a filler/bonder is disposed in each channel; and the outermost two glazing sheets each have an exposed outer face.
6. A glazing unit as claimed in claim 4 or 5, wherein: the vapour barrier extends over the or each marginal edge of each exposed outer face and is bonded thereto.
7. A glazing unit as claimed in any preceding claim in combination with a frame, wherein: the frame has a channel receiving the or each edge of the glazing unit; and a frame seal engages with the marginal edge(s) of at least one outer face of the glazing unit.
8. A glazing unit as claimed in claim 7 when dependent on claim 6, wherein: the frame seal engages with the vapour barrier.
9. A glazing unit as claimed in claim 7 when dependent on claim 6, wherein: the vapour barrier stops short of the frame seal.
10. A glazing unit as claimed in any preceding claim, wherein: the vapour barrier is in the form of a tape.
11. A glazing unit as claimed in claim 10, wherein: the tape is bonded to the glazing sheets and/or filler/bonder by adhesive.
12. A glazing unit as claimed in any preceding claim, wherein: the vapour barrier comprises a metal.
13. A glazing unit as claimed in claim 12, wherein: the metal is ductile.
14. A glazing unit as claimed in claim 12 or 13, wherein: the metal is copper, aluminium, lead or an alloy including copper, aluminium or lead.

-10 -
15. A glazing unit as claimed in any of claims 12 to 14, wherein: the metal has a thickness not exceeding 0.25 mm.
16. A glazing unit as claimed in any of claims 12 to 14, wherein: the metal has a thickness not exceeding 0.05 mm.
17. A glazing unit substantially as described with reference to the drawings.
18. A method of manufacture of a glazing unit, comprising the steps of: disposing a spacer between two glazing sheets so that the glazing sheets are arranged parallel to, and spaced apart from, each other, and so that the spacer extends along the or each edge of the sheets, inset from the edge(s) so that a channel is formed at the edges of the glazing sheets; then inserting a filler/bonder into the channel and allowing the filler/bonder to bond to the glazing sheets and the spacer to hold the glazing sheets and spacer together; and then bonding a vapour barrier which is impervious to water vapour to the or each outer edge of the glazing unit so that the vapour barrier extends around the or each outer edge of the glazing unit and covers the or each outer edge of the filler/bonder.
19. A method as claimed in claim 18, wherein: the method produces a glazing unit having the features of any of claims 2 to 16.
20. A method as claimed in claim 19 when dependent on claim 11, wherein: the tape is self-adhesive.
21. A method of manufacture of a glazing unit, substantially as described with reference to the drawings.