GB2217765A - Secondary insulation seals - Google Patents

Abstract

A seal (10) for secondary insulation sheets (36), comprises first and second elements. The first element (2) is an extruded channel section of relatively rigid plastics material adapted to clip onto the edge of a sheet of secondary insulation. The second element (1) is an extruded tube section (9) of relatively soft elastomeric material. The two elements are connectible together by a T-section flange disposed on the tube section which is received by two L-section flanges disposed one arm of the channel section element. When the channel section is fitted over an edge of said sheet of secondary insulation, the tube section is squeezed between said arm and glazing or a glazing bar to which said secondary insulation is applied. <IMAGE>

Description

Secondary insulation seals This invention relates to seals for use in the secondary insulation of glazed surfaces of buildings, particularly roofs thereof, and to secondary insulation systems incorporating such seals.

Many buildings have glass roofs or roofs which incorporate large areas of glass and many owners or tenants of such buildings are beginning to appreciate the savings which can be made in their energy requirements by insulating their buildings against heat loss.

Consequently, particularly for the glazed parts of roofs of buildings, it is now common to apply sheets of twin walled polycarbonate, which is a clear plastics material. By virtue of the air gap between the layers, such polycarbonate sheets offer extremely effective heat insulation. A major consideration in its use on roofs, however, is its lightness to strength ratio, which far exceeds that of even reinforced glass. Consequently, its use on existing buildings does not entail the cost of reinforcing roof supports, which is frequently required when double glazing is employed.

In our copending application entitled "Glazing bar sections" which is filed coincidentally with the present application and which claims priority from application numbers 8807747.4 and 8815178.2 filed 31 March 1988 and 25 June 1988 respectively, there is provided a means of connection of secondary insulation to primary glazing which is supported by glazing bars of substantially T-shaped section, the bars of the T supporting adjacent sheets of glazing and the stem of the T upstanding between said sheets, said means comprising an extruded glazing bar section in one or more parts and defining opposing slots adapted to receive and retain adjacent sheets of said secondary insulation and connection means for connection of said section to said upstanding stem, said means for connection at least including a channel having internal catches adapted to engage with a corresponding flange.

A large gap is however left between the secondary insulation and the existing glazing, which of course accounts for a large part of the extra insulation provided by the secondary insulation system. This gap needs to be isolated from the outside for two reasons. Firstly, if a gap is left, then the wind can catch and pull at the secondary insulation and possibly dislodge it. While this was a particular problem with the existing method of connection of the insulating sheets to the existing glazing and the invention defined in our copending application largely reduces this problem, nevertheless the possibility of a strong wind getting underneath and dislodging the insulating sheets cannot be entirely ruled out. In any event, the gap should be sealed to reduce drafts between the sheets of glazing and insulation which would severely impair the insulating effects of the secondary insulation.

Hitherto, this gap has been sealed by a an extruded plastics section comprising a channel for connection to the edge of the secondary insulation sheet and having a downwardly dependent flap adapted to lie and seal against the glazing below. A problem with this arrangement is that the seal is not securely held in position and can, in time, come adrift.

Thus it is an object of the present invention to provide an improved seal which does not suffer from, or at least mitigates, these disadvantages.

In. accordance with a first aspect of the present invention there is provided a seal for secondary insulation sheets, which seal comprises first and second elements, the first element comprising an extruded channel section of relatively rigid plastics material adapted to clip onto the edge of a sheet of secondary insulation, and the second element comprising an extruded tube section of relatively soft elastomeric material, the first and second elements including means to connect them together along one arm of said channel section such that, in use when the channel section is fitted over an edge of said sheet of secondary insulation, the tube section is squeezed between said arm and glazing or a glazing bar to which said secondary insulation is applied.

Preferably said two elements of the seal are connectible together by means of a T-section flange disposed on the tube section element adapted to be received by two facing L-section flanges disposed on said one arm of the channel section element. The seal is thus assembled by sliding the T-section flange of the tube section element along the slot formed by said two facing L-section flanges on the channel section element.

This seal finds particular application with a glazing bar section as defined in our abovementioned copending application and accordingly the present invention also provides, in a second aspect thereof, a secondary insulation system for an existing roof glazing system which is supported by glazing bars of substantially T-shaped section, the bars of the T supporting adjacent sheets of glazing and the stem of the T upstanding between said sheets, said secondary insulation system comprising: an extruded glazing bar section in one or more parts and defining opposing slots; adjacent sheets of insulating material received and retained in said slots; means for connection of said section to said upstanding stem, said connection means at least including a channel having internal catches adapted to engage with a corresponding flange; and a seal as defined above which is clipped to those edges of the secondary insulation sheets which are not received and retained by said slots to seal the gap between said secondary and primary glazing.

The present invention is further described hereinafter, by way of example only, with reference to the accompanying drawings, in which: Fig 1 is a part perspective view of a seal in accordance with the first aspect of the invention; Fig 2 is a plan view of a secondary insulation system in accordance with the second aspect of the present invention; Fig 3 is a section along the line A-B in Fig 2 of a secondary insulation system according one embodiment of the second aspect of the present invention; and, Fig 4 is a section along the line A-B in Fig 2 of a secondary insulation system according to another embodiment of the second aspect of the present invention.

With reference to Fig 1, a seal 10 according to the first aspect of the invention comprises a first element 2 connected to a second element 1. The first element 2 is an extruded section of a relatively rigid plastics material and has the form of a channel section having a base 3 and arms 4,5. The arm 4 is provided with two downwardly depending L-section flanges 6,7 which face one another to form a slot 8. Despite its relative rigidity, the material of the element 2 nevertheless has a certain resilience to enable it to grip and hold a sheet of insulating material of appropriate dimensions inserted between its arms 4,5.

The second element 1, on the other hand, is extruded form relatively soft elastomeric material and is in the form of a tube section 9 having a flanged T-section 11 which is adapted, as shown in Fig 1, to fit and be retained in the slot 8 formed by said flanges 6,7.

With reference to Fig 2, a secondary glazing system 90 comprises sheets 36 of insulating material comprising twin walled polycarbonate plastics. Such sheets are laid on top of existing glazing on glazing bars 12 (only one of which is shown) which support adjacent sheets of glazing. Sides 35 of the sheets 36 are retained by glazing bar sections 50,70 described further below and ends 37 of the sheets 36 are sealed against the glazing below by seals 10.

Turning to Fig 3, adjacent sheets 18,20 of glazing are supported by an inverted T-section glazing bar 12 having arms 14,16 and a central flanged extension 15. Seals 22,24 seal the glazing 18,20 against the arms 14,16 respectively. A glazing bar section 50 comprises a channel section 52 incorporating internal catches 54. Legs 56,58 extend from the sides of the channel 52. Two deep mutually opposing slots 60,62 are disposed in the region of the base of the channel 52.

The channel 52 is positioned over the glazing bar 12 and the catches 54 are engaged with the flanged extension 15. In this position, the legs 56,58 press against and retain in position the glazing 18,20. The slots 60,62 are employed to retain the side edges 35 of adjacent sheets 36 of twin walled polycarbonate.

The ends 37 of each sheet 36 are sealed against the glazing below by a seal 10 as described with reference to Fig 1. Here, the seal 10 is pressed against a the glazing 20 to deform the tube section element 1. This ensures a good seal against the glazing 20 so that the enclosed space 100 provides effective insulation and so that wind cannot get under the sheet 36 and possibly dislodge it. Furthermore, the seal 10 itself is in this way securely held in place, both by the grip on the sheet 36 by the channel section element 2 and by the friction between the glazing 20 and compressed tube section 1.

With reference to Fig 4, similar components are referred to by the same reference numeral as used in the description of Fig 3. Where parts differ slightly, the same numeral is used but with an inverted comma.

In this respect, not all glazing systems to which it may be desired to add secondary insulation incorporate gazing bars as shown in Fig 3. In Fig 4 for instance, a glazing bar 12' is shown in which the central extension 15' is not flanged. Here the glazing 18,20 is retained in position by lead flashings 66,68.

In this situation therefore (and for other varieties of glazing bar), a substantially universal glazing bar section 70 for attachment of secondary insulation is provided. The section 70 is in two parts. A first part 80 is adapted to be connected to a second part 90, and for this purpose is provided with a channel 52' having catches 54'.

The second part 90 is provided with a flanged head 94 and a deep channel 92 adapted to fit over the extension 15'. To retain the part 90 in place, self drilling bolts 96 may be employed although any other suitable means could also be used if preferred. The channel 52' is positioned over the part 90 until the catches 54' snap into engagement with the flanged head 94. The first part 80 has opposing slots 60,62 which retain the side edges 35 of secondary insulation sheets 36.

[If the glazing bar 12 was in some other form than shown in the drawings, then the channel 92 in the second part 90 would be replaced by a different shape which facilitates permanent connection of the part to the glazing bar. In all events however, the second part 90 is always provided with flanged head 941.

In Fig 4, instead of the sheet 36 being sealed at its end 37 against the glazing 20, it is sealed against a lower glazing bar 13. This provides an even larger air gap 100 between the insulation sheet 36 and glazing 20. In any event, the seal 10 is always arranged so that the tube section element 1 is compressed to form an airtight seal.

Our abovementioned copending application discloses a further embodiment of glazing bar section which is hereby included herein by reference to that application. The glazing bar section there disclosed is equally applicable to the secondary insulation systems described herein.

While the invention has been described with reference to specific elements and combinations of elements, it is envisaged that each element may be combined with any other or any combination of other elements. It is not intended to limit the invention to the particular combinations of elements suggested. Furthermore, the foregoing description is not intended to suggest that any element mentioned is indispensable to the invention, or that alternatives may not be employed. What is defined as the invention should not be construed as limiting the extent of the disclosure of this specification.

Claims (4)

1. A seal for secondary insulation sheets, which seal comprises first and second elements, the first element comprising an extruded channel section of relatively rigid plastics material adapted to clip onto the edge of a sheet of secondary insulation, and the second element comprising an extruded tube section of relatively soft elastomeric material, the first and second;elements including means to connect them together along one arm of said channel section such that, in use when the channel section is fitted over an edge of said sheet of secondary insulation, the tube section is squeezed between said arm and glazing or a glazing bar to which said secondary insulation is applied.

2. A seal as claimed in claim 1 in which said two elements of the seal are connectible together by means of a T-section flange disposed on the tube section element adapted to be received by two facing L-section flanges disposed on said one arm of the channel section element.

3. A secondary insulation system for an existing roof glazing system which is supported by glazing bars of substantially T-shaped section, the bars of the T supporting adjacent sheets of glazing and the stem of the T upstanding between said sheets, said secondary insulation system comprising: an extruded glazing bar section in one or more parts and defining opposing slots; adjacent sheets of insulating material received and retained in said slots; means for connection of said section to said upstanding stem, said connection means at least including a channel having internal catches adapted to engage with a corresponding flange; and a seal as claimed in claim 1 or 2 which is clipped to those edges of the secondary insulation sheets which are not received and retained by said slots to seal the gap between said secondary and primary glazing.

4. A secondary insulation seal and system substantially as hereinbefore described with reference to the accompanying drawings.