GB2150185A - Double glazed window unit - Google Patents

Abstract

A window arrangement comprising one or more double glazed units 1 in a fixed frame 2; each double glazed unit comprising two spaced apart inner 21 and outer 20 glazing panels mounted in a metallic frame 4 extending in an unbroken manner from a position 17 inwardly of the inner panel 21 to a position 6 outwardly of the outer panel 20; at least one seal 34 between the double glazed unit frame and its associated part of the fixed frame; the surface area of that part of the metal members on the inner side of the seal being sufficiently greater than the surface area of that part of the metal members externally of the seal that, in use and with any openable window of the unit closed, the surface temperature of the internal part is maintained at a temperature above that of the external atmosphere by at least 70 per cent of the difference between the air temperatures measured in degrees centrigrade internally and externally of the window. A further seal may be provided at point A. <IMAGE>

Description

SPECIFICATION Window This invention relates to double glazed windows.

Much development work has been carried out on the design of metallic extrusions for window frames and, for double glazing, these generally have a multiplicity of parts to permit the frame to be assembled and subsequently glazed with a sealed unit of two sheets of glass bonded to a spacer, the unit being set in the frame using gaskets and wedges. In order to avoid condensation problems on the inner face or "warm" side of the window it is well known to provide a "thermal break" generally of a plastics material as an integral part of the frame.

The present invention is concerned with an improved construction of double glazed window unit which may be arranged to provide enhanced protection against condensation without the incorporation of a thermal break.

According to the present invention there is provided a double glazed window unit having metal members surrounding the unit and constituting a fixed unit frame; each window comprising two spaced apart inner and outer glazing panels mounted in a metallic frame and located in the frame; the metal members of the unit frame extending in an unbroken manner from a position inwardly of the inner panel to a position outwardly of the outer panel: at least one seal between the metallic frame and its associated part of the unit frame; the surface area of each first part of the metal members and of the metallic frame on the inner side of the seal being sufficiently greater than the surface area of each second part of the metal members and of each metallic frame externally of the unit so that, in use and with any openable window of the unit closed, the surface temperature of the first parts is maintained at no less than 70 per cent of the difference between the air temperatures measured in degrees centigrade internally and externally of the unit. Preferably the surface area of each first part is at least 1.5 times and may be from 2 to 5 times the surface area of each second part.

The metallic frame preferably comprises at least two frame members each of which is a single metallic extrusion having two spaced apart parallel grooves linked by a spacer part; inner and outer glazing panels having their edges respectively disposed within the grooves of each member and directly bonded within the grooves by a sealant/adhesive and without the interposition of any gaskets, the panels and the frame members together constituting an integrated load absorbing structure.

Preferably the sealant/adhesive is of a kind that remains flexible after it has set.

Each extrusion may have an outer edge part for receiving hinges when the window is to be openable and an inner part extending in spaced relation to the inner glazing panel and for engagement with securing members when the window is to be fixed. The outer edge part and the spacer part may constitute opposed walls of an enclosed hollow space. The spacer part may be formed with perforations and the hollow space may contain a hygroscopic substance such as silica gel.

The members may be joined at their adjacent corners by brackets which are screwed or cleated thereto.

The invention will now be described by way of example with reference to the accompanying drawings in which:~ Fig. 1 is a vertical section through the lower part of a window according to the present invention in association with an outer frame and, Fig. 2 is a horizontal section through two adjacent windows in association with a mullion.

Referring to Fig. 1 a double glazed window 1 is mounted in an outer frame 2 by brackets 3. The window 1 is rectangular and comprises four frame members, one of which is shown at 4, extruded from an aluminium alloy and having an outer edge part 5, an outer wall 6 and a longer inner wall 7. The walls 6 and 7 are separated by a spacer part 8 the outer ends 9 and 10 of which are shaped to provide re-entrant grooves 11 and 12 having lips 13 and 14. The upper end 15 of the wall 7 is extended outwardly as a part 15 and then downwardly as an inner part 17 spaced from the wall 7.

The lips 13 and 14 are respectively spaced from the walls 6 and 7 by distances to receive the lower ends 18 and 19 of glazing panels 20 and 21 as clearance fits. The lower ends 18 and 19 are bonded directly within the respective grooves using a conventional settable composition that preferably remains flexible after setting. This composition is shown in black within the grooves 11 and 12 and extends beneath the lower ends of the panels and upwardly between the panels and the respective walls 6 and 7. On the assumption that the panels 20 and 21 are rectangular it will be understood that each edge will be accommodated within the grooves of a frame member which may conveniently have their adjoining corners mitred in conventional fashion.

This arrangement has been found to be simple to assemble and provides a very strong window construcion without placing reliance upon the fundamental strength of a pre-assembled frame. In fact the strength of the window is primarily embodied in the strength of the panels 20 and 21. When the latter are glass the slight flexibility provided by the settable composition prevents residual strains from remaining in the panels. Thus the panels and the frame members together constitute an integrated load absorbing structure.

Although it is not essential the corners of the frame members 4 may be joined by brackets 22 in conventional manner the limbs 23 and 24 (Fig. 2) of which extend along the inner surface of the outer edge part 5 and may be screwed or cleated thereto by means not shown.

It will be apparent that the outer edge part 5 and the spacer part 8 constitute opposed walls of an enclosed hollow space 25 which may contain a hygroscropic substance (not shown) such as silica gel and in this case the spacer part 8 is formed with perforations such as 26 so that the atmosphere between the panels 20 and 21 may remain dry. Alternatively this space may contain an inert gas in known manner.

In a modification the spacer part 8 may follow the chain lines 8a so that the groove 12 is replaced by a groove 12a at the upper end 15 of the wall 7. Such arrangement improves the "sight line" from outside the window but does require the panels 20 and 21 to be of different sizes. If desired the groove 12a could be lengthened to extend downwardly to the position of the groove 12 when the same sized panels could still be used and the bond strength between the inner panel 21 and the frame member 4 would be increased.

The window 1 may be employed as a fixed or as an opening light. In Fig. 1 the window is shown in association with an outer frame 2 which may replace a wooden frame and be secured directly to a brick or other surround.

The outer frame 2 is conventionally rebated at 26 with a flat base 27 and an upstanding wall 28. When four frames 2 are joined together the rebate 26 constitutes a window opening to receive the window 1 with adequate clearance. Inwardly of the wall 28 the upper part of the frame 2 is recessed at 29 with a flat base 30. A series of spaced apart brackets 31 have one limb 32 secured by bolts (not shown) at the chain line position 33 and their other limb 34 engages behind the inner part 17 of each frame member 4 to hold the window 1 in spaced relationship within the rebate 26 and with the wall 7 pressed against a continuous sealing strip 34 located in a recess 35 in the wall 28 of the outer frame 2.

The recess 29 is closed by a snap fit cover 36 suitably recessed to accommodate the brackets 3.

This arrangement of fixed light presents a safety feature for facilitating the escape of occupants of a building in the case of fire.

The brackets 3 may be adequately strong to support the window for all normal purposes but may be distortable by the application of a large local force, such as by kicking, to re move the window bodily. Such force may be considerably less than that required to break through two panes of glass.

When the window 1 is to be an opening light the brackets 3 are not used and conventional hinges (not shown) are secured between the outer edge part 5 of one of the frame members 4 and the corresponding base 27 of the outer frame 2. The opposite outer edge part 5 and its corresponding part of the outer frame 2 will carry a suitable locking catch (not shown).

Fig. 2 shows two windows 1 a and 1 b in association with a mullion 36 which may subdivide the outer frame 2 and may be secured to the upper and lower horizontal parts thereof by conventional means. The mullion 36 has a hollow post 37 which rests upon the base 27 of the outer frame 2 and an inner part 38 formed with a central recess 39 and end recesses 40 and 41. These recesses are provided with snap fit covers 42, 43 and 44. The window 1 a is an opening light and is assumed to be hinged as described above to a part of the outer frame 2. Its vertical frame member 4 seals against a strip 34 in a wall 45 of the inner part 38. The window 1 b is a fixed light and is supported by brackets 3 as described above in connection with Fig. 1.

With all the above arrangements it has been found, by extensive experiments, that if sufficient surface area of metal frame (including the outer frame and the mullion) is provided on the "warm" side of the window, no condensation occurs on the inner side of the frame members for a wide range of climatic conditions. This very desirable feature is achieved without using a conventional thermal break in the frame and it can be enhanced for severe climatic conditions by providing an outer continuous seal at the positions marked "A".

In practice we have found that when the surface area on the "warm" side is at least 1.5 times greater than that on the cold side internal condensation does not occur with an external air temperature of say 0 C; an internal air temperature of up to 20 C and internal relative humidity of 70%. It is however preferred that the ratio of surface areas should be at least 2 to 5. However when considering this ratio, small air gaps can be considered as sealed and the external surface is only that part directly exposed externally of the unit.

Claims (9)

1. A double glazed window unit having metal members surrounding the unit and constituting a fixed unit frame; each window comprising two spaced apart inner and outer glazing panels mounted in a metallic frame and located in the frame; the metal members of the unit frame extending in an unbroken manner from a position inwardly of the inner panel to a position outwardly of the outer panel; at least one seal between the metallic frame and its associated part of the unit frame; the surface area of each first part of the metal members and of the metallic frame on the inner side of the seal being sufficiently greater than the surface area of each second part of the metal members and of each metallic frame externally of the unit so that, in use and with any openable window of the unit closed, the surface temperature of the first parts is maintained at no less than 70 per cent of the difference between the air temperatures measured in degrees centigrade internally and externally of the unit.

2. A unit according to claim 1 in which the surface area of each first part is at least 1.5 times the surface area of each second part.

3. A unit according to claim 1 in which the surface area of each first part is from 2 to 5 times the surface area of each second part.

4. A unit according to any one of the preceding claims in which the metallic frame comprises at least two frame members each of which is a single metallic extrusion having two spaced apart parallel grooves linked by a spacer part; inner and outer glazing panels having their edges respectively disposed within the grooves of each member and directly bonded within the grooves by a sealant and without the interposition of any gaskets, the panels and the frame members together constituting an integrated load absorbing structure.

5. A unit according to claim 4 in which the sealant is of a kind that remains flexible after it has set.

6. A unit according to claim 4 or claim 5 in which each extrusion has an outer edge part for receiving hinges when the window is to be openable and an inner part extending in spaced relation to the inner glazing panel and for engagement with securing members when the window is to be a fixed light.

7. A unit according to claim 6 in which the outer edge part and the spacer part constitute opposed walls of an enclosed hollow space.

8. A unit according to claim 7 in which the spacer part is formed with perforations and the hollow space contains a hygroscopic substance.

9. A double glazed window unit substantially as herein described with reference to Fig. 1 or Fig. 2 of the accompanying drawing.