GB2072250A

GB2072250A - Double glazing systems

Info

Publication number: GB2072250A
Application number: GB8109038A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-03-22
Filing date: 1981-03-23
Publication date: 1981-09-30

Abstract

A double glazing system comprises a plurality of adjacent window panes 3, separated by glazing bars 5, and over these a glazing arrangement which includes light transmitting elements 13 preferably GRP sheets which are spaced from the window panes 3 by means of spacing elements 11 so as to form an air gap of preferably 3 DIVIDED 4" between the panes 3 and the elements 13. Joins or gaps between adjacent elements 13 are covered by members 15, 17 so as to increase the thermal insulating properties of the double glazing system. <IMAGE>

Description

SPECIFICATION Double glazing systems The present invention relates to double glazing systems especially, though not exclusively, for use in industrial premises.

It is well known that single glazed windows are poor thermal insulators and so allow a considerable amount of heat to escape from the building in which they are fitted. In factory or other industrial buildings where glazing may form a considerable portion of the roofing or wall area of the building, the cost of the heat loss in winter may be extremely high. Conversely in summer when the sun may shine directly onto the glazed portions of the roof or wall of a factory the heat inside the building may rise to an unacceptable level because of the so-called greenhouse effect and, therefore, it may be necessary to provide relatively expensive air conditioning or cooling apparatus.

It has therefore become increasingly the practice to double glaze windows and other glazed areas by providing a second pane of glass, or similar translucent material fixed parallel to the existing windows, leaving an air gap between the panes, preferably of about 4311 Known double glazing systems are relatively effective thermal insulators compared to conventional single glazed windows but they are expensive and/or relatively heavy. It is particularly important in the case of factories, with a high proportion of glazed surfaces in their roof, to keep the weight as low as possible, otherwise additional strengthening supports may have to be provided in the roof.

A substantially cheaper and lighter double glazing system has included the use of translucent glass reinforced plastics (GRP) or other plastics materials as the second pane in a double glazing system. GRP has several advantages over glass for use as the second pane of a double glazed window, as it is less brittle (and so less prone to accidental or deliberate damage), is often cheaper, and is lighter, and so may more easily be fixed to an already existing single glazed window without the need for extra strengthening struts. However, the thermal insulation of a system utilising plastics material has not hitherto been as good as a system using only glass. This is mainly due to the method of fixing a plastics pane externally to the glass window frame.In order to provide an air space between the two panes in the glazing system the plastics pane is formed with an integral spacing flange projecting substantially normally from the pane on at least two parallel sides of the pane. The flanges are secured to the window frame by screws, adhesive or any other suitable method. Since windows vary enormously in shape and size, a very large number of plastics panes, with their integral flange, have to be provided. Therefore there is eventually a substantial loss of heat in the area of the window frame between two adjacent glass panes and to which adjacent plastics panes are attached in industrial glazing systems, particularly the socalled "patent glazing" system, glazing bars are provided which project from the plane of the glass pane at regular intervals along the glazed area.

These glazing bars support the glass from beneath and provide a retaining seal on the glass which engages the exterior side of the pane. Double glazing with panes of plastics material having flanges, as mentioned above, leaves an area over the external surface of the glazing bar uninsulated and, particularly in industrial situations, this uninsulated area may comprise a substantial portion of the total surface area.

According to the present invention there is provided a double glazing system comprising a plurality of adjacent window panes, each pane being separated from the or each adjacent window pane by one or more glazing bars, and a glazing arrangement extending substantially continuously over said window panes and the or each glazing bar, said glazing arrangement including one or more light transmitting elements.

Also provided by the present invention is a method of double glazing a plurality of window panes, each window pane being separated from the or each adjacent window pane by one or more glazing bars, the method comprising locating substantially parallel to the or each of said window panes a glazing arrangement including one or more light transmitting elements, said glazing arrangement extending substantially continuously over said window panes and glazing bars.

The provision of a substantially continuous glazing arrangement, over a glazing system such as patent glazing, where window panes are held in position by glazing bars or astragals, allows a greater thermal insulating effect to be obtained than conventional double glazing for such systems.

Preferably, said light transmitting elements are of a plastics material. More preferably they are of a glass reinforced plastics material.

Preferably, said light transmitting elements are substantially planar and extend across a window pane so as to define a substantially enclosed space between said light transmitting element and said window pane.

The use of planar plastics elements in the form of, for instance, GRP sheets, makes the double glazing system of the present invention lighter in weight than conventional glass double glazing, allowing the use of the system in situations for which glass double glazing may be unsuitable, such as factory rooflights.

Preferably, said glazing arrangement includes one or more spacing members attached to said window panes and/or glazing bars and which serve to space said light transmitting elements from said window panes.

Preferably said spacing members are separate from said light transmitting elements. However, in the alternative, said spacing members are integral with said light transmitting elements.

Preferably said spacing members are of wood, metal or a plastics material. More preferably, said spacing members are of box, U, L, T or H cross sectional shape.

Preferably said glazing arrangement includes one or more capping members adapted so as substantially to cover the or each of the joints and/or gaps between adjacent light transmitting elements.

Preferably said the or each of said capping members are attached to the adjacent light transmitting elements and/or to a glazing bar.

Preferably or each of said capping members are of wood, metal or a plastics material.

Preferably there is an air gap of between 4" and 1 4n perpendicularly between a window pane and an associated light transmitting member. More preferably, said gap is between 2111 and 1". Most preferably said gap is approximately -".

A double glazing system according to the present invention is particularly suitable for runs of patent glazing in, for example, factory roofs or external walls, where the light weight of the system makes such systems preferable to conventional glass double glazing, Glazing bars in patent systems are of many designs, and often they project from the surface of the window panes a distance greater or less than the -" which is the optimum air gap for effective thermal insulation in double glazing systems. A spacing frame may therefore be required to support the light transmitting elements, such as GRP sheets, the desired distance from the window panes.If the glazing bars project beyond the exterior surface of the light transmitting elements, then capping elements are required to cover the glazing bars so as to preserve the continuity and hence thermal integrity of the glazing arrangement.

Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic cross-sectional view through a double glazed window system according to the present invention; Figure 2 is a diagrammatic perspective view of the double glazed window system of Figure Figure 3 is a diagrammatic cross-sectional view through a second embodiment of a double glazing window system according to the present invention and Figure 4 is a diagrammatic cross-section through a third embodiment of the present invention.

Referring to Figures 1 and 2, a double glazing system according to the present invention indicated generally by 1, comprises glass panes 3 held in position by conurentional glazing bars 5.

This forms the conventional single glazing system known as "patent glazing". The glazing bars 5 are of well known design and may be of plastics material, metal or any other suitable material. The glass panes 3 are held in position by the glazing bars 5 by means of the lower flanges 9 and upper flanges 7 of the glazing bars 5. The glazing bars 5 themselves are supported by conventional means, for instance, in the roofing area of a factory building. The distance between parallel adjacent glazing bars 5 is typically approximately 61 0mm or approximately 2'.

In this embodiment of the present invention the existing "Patent Glazing" system is double glazed by the addition of a spacer frame to the existing installation. The spacer frame is formed by channel sectioned members 11 defining the sides, bottom and top of the double glazing system. In this embodiment the frame members 11 are of aluminium but other embodiments may have spacing frame members made of another metal, plastics materials, wood or other suitable materials.

The spacing frame members 11 lying parallel to the glazing bars 5 are retained in position by being slipped beneath the glass retaining portion of the upper flange 7. The spacing bars 11 lying perpendicular to the glazing bars 5 are fixed by means of a suitable adhesive to the external surface of the glass panes 3. In alternative embodiments the spacing frame members 11 may be held in position by means of screws, adhesives or any other suitable retaining means.

After the fixing of the spacer frame to the window one or more light transmitting elements of the desired size, in the form of glass reinforced plastics sheets 13 positioned on the spacer frame so as to cover the desired portion of the external surface of the window system. In this embodiment the fixing is achieved by means of screws passing through the plastics sheeting and engaging in a corresponding recess in each of the glazing bars 5.

In alternative embodiments such screws may engage with recesses in the the spacing frame members 11 or may be fixed by any other suitable method. As it may be desired to remove the plastics sheet for eventual replacement it may be advantageous for the fixing means to be of a nonpermanent nature which may preclude the use of adhesives.

Where edges of adjacent plastics sheet meet, a narrow strip of aluminium is provided to cover the join. The fixing screws pass through this aluminium cap 17 and thence into the glazing bars 5. In addition as the sheets of GRP material are of 4' in width each sheet spans two glazing bars.

There are, therefore, only joins in the GRP surface at alternate glazing bars. However, a retaining aluminium cap 1 7 is placed on the intermediate centre portion of the GRP sheet 1 3 so as to hold the central portion of the sheet in position on the glazing bar. Such an intermediate retaining member serves to prevent or reduce flexing of the plastics sheet under, for instance, windy conditions. In alternative embodiments of the present invention a similar effect may be achieved by the addition of stiffening ribs in the fabric of the plastics sheet or by increasing the thickness of the plastics sheet or by reducing the width of the sheet. Furthermore, in alternative embodiments the size of the plastics sheets may be such as to extend over one or more than two window panes.

Referring now to Figure 3, an alternative embodiment of the present invention comprises a conventional "patent glazing" system of a different design to that of the earlier embodiment of the present invention. The glazing bars 1 9 have no upper glass retaining flanges and also project from the surface of the existing glass a distance greater than the optimum 4" spacing between the glass and the plastics sheet. Therefore, a sheet 23 is required for each pane of existing glass. Sheet 23 therefore is of comparable size to the glass beneath it. However, the spacing frame members 21 are, in this embodiment, hollow squaresectioned members which are fixed with adhesive around the edges of each existing pane of glass.

The plastics sheet 23 is then fixed to the spacing frame as before. In alternative embodiments fixing means such as screws, rivets etc may be used.

In an embodiment such as that shown in Figure 3 it is important to provide a capping member 25 which may be of metal, plastics material or any other suitable material which covers the glazing bar 1 9 and also overlaps onto the upper surface of adjacent plastics sheets 23. The cap may then be fastened down by screws or adhesive to the sheets 23. The presence of a cap such as 25 is essential to increase the thermal insulation properties of the double glazing system, as otherwise heat may be lost by transmission through the glazing bar 1 9 and thence by radiation to the external atmosphere, as occurs in many conventional double glazing systems.

A third embodiment of the present invention, shown in Figure 4, comprises glass window panes 27 separated and held in position by glazing bars 29. A light transmitting element 31 is located over each pane 27, the element 31 being a moulded GRP sheet having integral spacing flanges 33 attached to the sides thereof. The feet 34 of the flanges 33 are positioned under the pane retaining member 36 of the glazing bar. The integral flanges 33 thus serve both to space the light transmitting element 31 the desired a" perpendicularly from the associated window pane 27, and to retain the light transmitting element in position. In alternative embodiments, adhesives, screws or other suitable means may be used to retain the elements in position.

The large gap 37 between adjacent light transmitting elements 31 may be a great source of heat loss from the interior of the building to which the double glazing system is fitted. Therefore, the gap 37, and the glazing bar 29, is covered by a plastics covering member 35, This is in the form of a strip running the length of the glazing bar 29, with a substantially shallow U-shaped crosssection. Lips 39 extend from the arms of the U so as to lie substantially parallel to the plane of the light transmitting elements 31. The lips 39 are fixed to the adjacent elements 31 by adhesive, although in alternative embodiments other fixing means may be used.

In embodiments of the present invention it may be desired to provide seals between, for instance, the light transmitting elements and the spacing frame members. These need not be air tight seals but serve to prevent water and dust from entering the glazing system, so reducing corrosion of the original single glazing installation. A suitable seal for such a purpose is that sold under the Trade Mark ARBOSEAL.

Also in order to further improve the thermal insulation properties of embodiments of the present invention, cavitities within the spacing frame members and/or around the existing glazing bars may be filled with an insulating material such as, for example, expanded polystyrene.

The plastics sheet may be of any suitable material but, by way of example only, that used in the embodiments described above utilised a translucent GRP material sold under the Trade Mark FILON and produced by British Industrial Plastics Ltd. of Sutton Coldfield, West Midlands.

It will be appreciated that a method for double glazing an existing single glazed window system according to the present invention may be used on the internal surface of the existing installation as well as on the external surface as required.

Furthermore, the existing installation may be at any angle to the horizontal from 0 to 90 to the horizontal, making a double glazing system in accordance with the present invention particularly suitable for use on existing factory rooflights where the lightweight, relatively easy installation and cheapness together with the high thermally insulating properties provide advantages over conventional double glazing systems. The high thermal insulation properties are illustrated by the fact that a double glazing system in accordance with the present invention may reduce the socalled "U" value (W/m2 "C) by a factor of approximately 2.

According to the choice of the plastics sheet the double glazing system in accordance with the present invention may, in addition to its thermal insulation properties, serve to reduce the effect of fire on the fabric of the building to which it is fitted, protect the original glazing system from corrosion, serve to protect the glass in the original glazing system from deliberate or accidental damage or allow the transmission of a defused light reducing glare and the dilatorious affects of ultra-violet light which may be especially important in certain industries.

Claims

1. A double glazing system comprising a plurality of ajdacent window panes, each window pane being separated from the or each adjacent window pane by one or more glazing bars, and a glazing arrangement extending continuously over said window panes and the or each glazing bar, said glazing arrangement including one or more light transmitting elements.

2. A double glazing system according to claim 1 wherein said light transmitting element are substantially planar and extend across a window pane so as to define a substantially enclosed space between said light transmitting element and said window pane.

3. A double glazing system according to claim 1 or claim 2 wherein said light transmitting elements are of a plastics material.

4. A double glazing system according to claim 3 wherein said plastics material is a glass reinforced plastics material.

5. A double glazing system according to any of the preceding claims wherein said glazing arrangement includes one or more spacing members attached to said window panes and/or said glazing bars, and to which said light transmitting elements are fixed.

6. A double glazing system according to claim 5 wherein said spacing members are separable from said light transmitting elements.

7. A double glazing system according to claim 5 wherein said spacing members are integral with said light transmitting elements.

8. A double glazing system according to any of claims 5, 6 or 7 wherein said spacing members are of wood, metal or plastics material.

9. A double glazing system according to claim 8 wherein said spacing members are of box, U, L, T or H cross-sectional shape.

10. A double glazing system according to any of the preceding claims wherein said glazing arrangement includes one or more capping members positioned so as substantially to cover the or each of the joints and/or gaps between adjacent light transmitting elements.

1 A double glazing system according to claim 10 wherein the or each of said capping members is attached to adjacent light transmitting elements and/or to one of said glazing bars.

12. A double glazing system according to claim 10 or claim 11 wherein said capping member is of wood, metal or a plastics material.

13. A double glazing system according to any of the preceding claims wherein the or each of said window panes and the or each of said light transmitting elements are relatively positioned so as to provide a gap of between " and 1-" perpendicularly from each of said window panes to the associated light transmitting element.

14. A double glazing system according to claim 13 wherein said gap is between 2" and 1".

1 5. A double glazing system according to claim 14 wherein said gap is ".

16. A double glazing system according to any of the preceding claims wherein said window panes and glazing bars are located in an external wall or roof of a building.

1 7. A double glazing system according to claim 1 6 wherein said glazing arrangement is positioned over the exterior of said window panes and glazing bars.

18. A double glazing system according to claim 1 and substantially as described herein.

19. A double glazing system according to claim 1 and substantially as described herein with reference to the accompanying drawings.

20. A method of double glazing a plurality of adjacent panes, each window pane being separated from the or each adjacent window pane by one or more glazing bars, the method comprising locating substantially parallel to the or each of said window panes, a substantially continuous glazing arrangement extending over said window pane and glazing bars, said glazing arrangement including one or more light transmitting elements.

21. A method of double glazing according to claim 20 wherein said light transmitting elements are of a plastics material.

22. A method of double glazing according to claim 21 wherein said plastics material is a glass reinforced plastics material.

23. A method of double glazing according to claim 20, claim 21 or claim 22 wherein said light transmitting elements are substantially planar, and extend across a window pane so as to define a substantially enclosed space between said light transmitting element and said window pane.

24. A method of double glazing according to any of claims 20 to 23 inclusive wherein said glazing arrangement includes one or more spacing members positioned between said light transmitting elements and said window panes and/or glazing bars.

25. A method of double glazing according to claim 24 wherein said spacing members are separable from said light transmitting elements.

26. A method of double glazing according to claim 24 wherein said spacing members are integral with said light transmitting elements.

27. A method of double glazing according to any of claims 24, 25 or 26 wherein said spacing members are of wood, metal or plastics material.

28. A method of double glazing according to claim 27 wherein said spacing members are of box, U, T, L or H cross-sectional shape.

29. A method of double glazing according to any of the claims from 20 to 28 inclusive, wherein said glazing arrangement includes one or more capping members positioned so as substantially to cover the or each of the joints and/or gaps between adjacent light transmitting elements.

30. A method of double glazing according to claim 29 wherein said capping members are attached to adjacent light transmitting elements and/or to a glazing bar.

31. A method of double glazing according to claim 29 or claim 30 wherein said capping member is of wood, metal, or a plastics material.

32. A method of double glazing according to any claim from 20 to 31 inclusive wherein there is a gap of between 4" and 1+" perpendicularly between the or each of said window panes and an associated light transmitting element.

33. A method of double glazing according to claim 32 wherein said gap is of between 2n and 1".

34. A method of double glazing according to claim 33 wherein said gap is of 4311,

35. A method of double glazing according to any of claims 20 to 34 inclusive wherein said window panes and glazing bars are located in an external wall or roof of a building.

36. A method of double glazing according to claim 35 wherein said glazing arrangement is positioned over the exterior of said window panes and glazing bars.

37. A method for providing a double glazing system according to claim 20 and substantially as described herein.

38. A method for providing a double glazing system according to claim 20 and substantially as described herein with reference to the accompanying drawings.