GB2310880A

GB2310880A - Double glazing unit with pressure equalising member

Info

Publication number: GB2310880A
Application number: GB9604953A
Authority: GB
Inventors: Graham Connor Robinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-03-08
Filing date: 1996-03-08
Publication date: 1997-09-10
Anticipated expiration: 2016-03-08
Also published as: GB2310880B; GB9604953D0

Description

IMPROVEMENTS IN QR RELATING TO DOUBLE GLAZED UNITS This invention relates to double glazed units and, more specifically, to a method for constructing a double glazed unit, comprising two panes of glass with a spacer bar therebetween.

Double glazed units are generally made by one of two systems. In one system, hereinafter called the "glass to glass" system, two panes of glass are heated until the side edges are flexible and the side edges are welding together, with the two panes of glass being supported to include a gap therebetween. With such a system it is the common practise to drill a small hole to the gap between the two panes of glass, to insert a small tube through the said hole and to release dry air into the unit to clear out substantially all the moisture from the air in the unit.

When the flushing with dry air is completed the hole is block, as by a lead slug.

.

This method of making a double glazed unit results in a* relatively stable unit and does not necessitate the inclusion of a desiccant in the gap between the two panels but the construction of such a double glazed unit is expensive and such all glass units are excluded from this present application.

In a cheaper and more common method for manufacture two panes of glass are spaced apart by a spacer bar, which lies between the edges of the two glass panes and the glass panes are secured to the spacer bar by an adhesive. The air trapped in the cavity formed by the panes of glass and the spacer bar will include water vapour from the surrounding atmosphere, which may condense to make the unit unsightly, and to overcome this problem it is the practise to include a desiccant in the cavity defined by the two sheets of glass and the spacer bar. As the desiccant absorbs moisture from the air in the cavity the cavity pressure is reduced to less than atmospheric pressure and one, or both, the panes of glass can be deflected inwardly by the reduced pressure, again making the unit unsightly.

The present invention seeks to provide a method for making a double glazed unit which can eliminate, or at least reduce, the deflection of the glass due to the internal pressure in the unit falling below an unacceptable level.

According to the present invention there is provided a method for making a double glazed unit comprising the steps of making the double glazed unit to comprise two panes of glass held apart by a spacer bar, including in the cavity defined by the glass panes and the spacer bar a desiccant to reduce the water vapour available within the cavity and including in said cavity an expandable volume, closed to the atmosphere within the cavity but open to the surrounding atmosphere.

Preferably, the method includes the steps of forming the spacer bar to define a hollow, generally rectangular, cross-section.

In a preferred embodiment the method includes the steps of retaining the two panes of glass with the spacer bar using an adhesive applied therebetween.

In a preferred embodiment the method is defined by the steps of arranging the spacer bar to be rectangular, and formed from a single length of extruded plastic moulding, and cutting the two ends of the length of extruded plastics to lie at an angle of 45 , cutting three right-angled notches in the length of extruded plastics and the length of extruded plastics at the three notches to form a rectangular frame.

Preferably the method includes the steps of inserting a corner key, into the open ends of the bent rectangular frame to retain the free ends of the spacer bar.

In a preferred embodiment the method includes the steps of using a resilient inflatable balloon to define the expansible volume.

In another embodiment the method includes the steps of using a flexible hollow body, with zig-zag folds along two opposite side edges, to define the expandable volume.

In one embodiment the atmosphere entry to the expandable volume is via an opening in the corner key.

In such an embodiment an opening formed in the adjacent corner of the spacer bar opens the expandable volume to communication with the surrounding atmosphere.

In a preferred embodiment the expandable volume is located within the spacer bar.

In a preferred embodiment the method includes the steps of forming the extrusion from which the spacer bar is made as a hollow, generally rectangular, cross-section, with flanges extending from said rectangular cross-section forming surfaces for engagement with the edges of the glass panels forming the double glazed unit.

The invention also envisages apparatus for carrying out the methods according to the invention.

The invention will now be described further by way of example with reference to the accompanying drawings in which: Fig 1 shows a cross-section through a side edge region of a double glazed unit in accordance with the invention., Fig 2 shows a plan view of a length of extruded plastics material prior to said material being folded into a rectangular spacer bar.

Fig 3 shows, in prospective view, a corner key being fitted to the free ends of the spacer bar to support an expandable volume within the spacer bar and, Fig 4 shows part of a longitudinal cross-section through the corner assembly illustrated in Fig 3.

In the illustrated example a double glazed unit is formed by two panes of glass 11 and 12 with a rectangular space bar 13 therebetween.

As will be seen from Fig 2 the spacer bar 13 is formed from a length of extruded plastics moulding 14, the ends 14a and 14b of which are cut at an angle of 45 , and three rightangled notches 14c, 14d and 14e are made along the length of the moulding 14. The distance Da between the end 14a and the notch 14c equals the distance D between notches 14d and 14e and the distance Db between notches 14c and 14d equals the distance Dd between notch 14e and the free end 14b so that, when the moulding 14 is bent through 90" at each of the notches 14c, 14d and 14e and the ends 14a and 14b lie closely adjacent, the moulding 14 is in the form of a rectangular frame. The rectangular frame may be welded or adhesively coated along the adjoining surfaces of the notches 14c, 14d and 14e and along the end surface of ends 14a and 14 so that the moulding 14 will form a closed, relatively tight rectangular spacer bar having two major sides of equal length and two minor sides of equal length.

As will been seen most clearly from Fig 1 the extruded plastics moulding 14 has a generally rectangular crosssectional area with one side 14f of the rectangle extending outwardly from the rectangle, in a common plane, to define flanges 14g and 14h. The two side walls 14i and 14k of the cross-section extending from the side 14f lie in spaced apart substantially parallel relationship and the side 141, opposite to side 14f, includes two outwardly inclined flanges 14m and 14n. With such a cross-section, and when forming the angled ends 14a and 14k and the notches 14c, 14d and 14e, the wall 14f forms a continuous wall along the moulding 14.

At the corner defined by the junction of ends 14a and 14b the spacer bar 13 includes a corner key 15 defined by two arms 15a and 15b at right-angles for the key 15. The arms 15a and 15b have a substantially hollow rectangular crosssection and the arm 15a inserts into the hollow crosssection of the end of the spacer bar 13 immediately adjacent the end l4a, and the arm 15 inserts readily into the hollow cross-section of the spacer bar 13 adjacent the end 14b. Thus, when the arms 15a and 15k are inserted into the respective ends of the spacer bar 13, and the ends 14a and 14b of the moulding 14 are brought into contacting relationship the corner key assists in retaining the rectangular form for the frame defined by the spacer bar 13.

Further, the corner key 15, is of hollow substantially rectangular cross-section, the free end of arm 15a is closed by an end wall 15c and the end of arm 15b is closed by a pleated sleeve 16 secured to the end of arm 15b, The pleated sleeve 16 is closed at its end remote from the arm 15b and the interior of the pleated sleeve 16 is open to the interior of the arm 15b. The interior of the corner key 15 communicates with the external atmosphere via a hole 15, through the external corner of the corner key 15 and which communicates with an opening 14e formed at the external corner defined by the junction of ends 14a and 14k.

In an alternative embodiment (not shown) the expandable volume may be defined by a resilient inflatable balloon, having its open end attached to the arm 15b so that the only opening to the balloon is via the atmosphere in the corner key 15, and the interior of the balloon is connected to atmosphere via the openings 15e and 14p.

When the double glazed unit according to the invention is being constructed a length of plastics moulding 14 is angled at 14a, 14k and notched at 14c, 14 and 14e, the length is then folded to form a rectangle and the corner key 15 with an inflatable volume 16 is inserted into the ends of the folded moulding adjacent ends 14a and 14b. The junctions of the rectangle, formed by notches 14c, 14d and 14e, and the junction of ends 14a and 14b are then welded, as by an adhesive, to make the spacer bar 13 relatively stable.

The sides 14i and 14k are then coated with an adhesive 17, and the two glass panes 11 and 12 are applied to opposite sides of the spacer bar 13. When the panes 11 and 12 are applied the panes 11 and 12 are spaced apart in parallel relationship by the tips of notches 14m and 14n, the adhesive 17 will flow to make a relatively major contact with the panes 11 and 12 and when so arranged the edges of the panes 11 and 12 will lie within the flanges 14g and 14h to retain the panes in their correct position as the ladhesive sets.

Claims

1. A double glazed unit comprising two panes of glass held apart by a spacer bar to define a cavity, a desiccant in the cavity to reduce the water vapour available within the cavity, and an expandable volume in the cavity and closed to the atmosphere within the cavity but open to the surrounding atmosphere.

2. A unit according to claim 1, wherein the spacer bar defines a hollow, generally rectangular, cross-section.

3. A unit according to claim 1 or 2, wherein the two panes of glass are attached to the spacer bar by means of an adhesive applied therebetween.

4. A unit according to any one of the preceding claims, wherein the spacer bar is substantially rectangular, and formed from a single length of extruded plastic moulding, the two ends of the length of extruded plastics are cut to lie at an angle of substantially 45 , three right-angled notches are cut in the length of extruded plastics and the length of extruded plastics is bent at the three notches to form a substantially rectangular frame.

5. A unit according to claim 4, further comprising a corner key inserted into the open ends of the bent substantially rectangular frame to retain the free ends of the spacer bar.

6. A unit according to claim 5, wherein the atmosphere enters the expandable volume via an opening in the corner key.

7. A unit according to claim 6, further comprising an opening formed in the adjacent corner of the spacer bar for opening the expandable volume to communication with the surrounding atmosphere.

8 A unit according to any one of the preceding claims, further comprising a resilient inflatable balloon for defining the expansible volume.

9. A unit according to any one of claims 1 to 7, further comprising a flexible hollow body, with zig-zag folds along two opposite side edges, for defining the expandable volume.

10. A unit according to any one of the preceding claims, wherein the expandable volume is located within the spacer bar.

11. A unit according to any one of the preceding claims as dependent upon claim 4, wherein the extrusion from which the spacer bar is made is formed as a hollow, substantially rectangular cross-section, with flanges extending from said substantially rectangular cross-section forming surfaces for engagement with the edges of the glass panels forming the double glazed unit.

12. A method of making a double glazed unit comprising the steps of making the double glazed unit to comprise two panes of glass held apart by a spacer bar, including in the cavity defined by the glass panes and the spacer bar a desiccant to reduce the water vapour available within the cavity and including in said cavity an expandable volume, closed to the atmosphere within the cavity but open to the surrounding atmosphere.

13. A method according to claim 12, further comprising the step of forming the spacer bar to define a hollow, substantially rectangular, cross-section.

14. A method according to claim 12 or 13, further comprising the step of retaining the two panes of glass with the spacer bar using an adhesive applied therebetween.

15. A method according to any one of claims 12 to 14, further comprising the steps of arranging the spacer bar to be substantially rectangular, and formed from a single length of extruded plastic moulding, and cutting the two ends of the length of extruded plastics to lie at an angle of substantially 450, cutting three substantially right-angled notches in the length of extruded plastics and bending the length of extruded plastics at the three notches to form a substantially rectangular frame.

16. A method according to claim 15, further comprising the step of inserting a corner key, into the open ends of the bent substantially rectangular frame to retain the free ends of the spacer bar.

17. A method according to any one of claims 12 to 16, further comprising the step of using a resilient inflatable balloon to define the expansible volume.

18. A method according to any one of claims 12 to 16, further comprising the step of using a flexible hollow body, with zigzag folds along two opposite side edges, to define the expandable volume.

19. A method according to any one of claims 12 to 18, further comprising locating the expandable volume within the spacer bar.

20. A method according to any one of claims 12 to 19 as dependent upon claim 15, further comprising the step of forming the extrusion from which the spacer bar is made as a hollow, generally rectangular, cross-section, with flanges extending from said rectangular cross-section forming surfaces for engagement with the edges of the glass panels forming the double glazed unit.

21. A double glazed unit substantially as hereinbefore described with reference to the accompanying drawings.

22. A method of making a double glazed unit, the method substantially as hereinbefore described with reference to the accompanying drawings.