Patent Grant
6868648
1. Field of the Invention
This invention relates generally to glazing-and-frame construction and more particularly to fenestration sealed frame, insulating glazing panels.
2. Description of the Prior Art
A conventional window consists of an insulating glass unit supported within a separate frame. Traditionally, the frame was made from wood or metal profiles, but increasingly plastic profiles made from such materials as polyvinyl chloride (PVC) or pultruded fibreglass are being substituted.
A traditional insulating glass unit generally consists of two or more glass sheets that are typically separated by a hollow aluminum spacer bar that is filled with desiccant bead material. With a conventional dual-seal unit, thermoplastic polyisobutylene material is applied to the spacer sides, and the outward facing channel between the glazing sheets and the spacer is filled with structural thermosetting sealant.
Because of the high thermal conductivity of the aluminum spacer, various efforts have been made in recent years to manufacture the hollow spacer from rigid low conductive plastic material. U.S. Pat. No. 4,564,540 issued to Davies describes the substitution of a rigid hollow fibreglass pultrusion for the aluminum spacer. Although a substantial development effort was carried out, this product has not yet been successfully commercialized and the technical problems include moisture wicking at the corners, glass stress breakage, and poor argon gas retention.
One solution to the problem of glass stress breakage is to manufacture the spacer from flexible material. U.S. Pat. No. 4,831,799 issued to Glover et al describes a flexible rubber foam spacer that is desiccant-filled with pre-applied pressure sensitive adhesive on the spacer sides. This flexible foam spacer has been commercialized under the name of Super Spacer®. In addition to featuring a low conductive spacer, another innovative feature of a Super Spacer® edge seal is that the traditional roles of the two perimeter seals are reversed. The inner PSA seal is the structural seal, while the outer seal is the moisture/gas barrier seal that is typically produced using hot melt butyl sealant.
In the past ten years, other warm-edge technologies have been developed where the traditional aluminum spacer has been replaced by a spacer made from a more insulating material, and these other warm-edge technologies include PPG's Intercept® and AFG's Comfort Seal® product. In total, these thermally improved warm-edge technologies have now gained about an 80 per cent share of the North American market.
In addition to reducing perimeter heat loss, these new warm edge products can also improve the efficiency and the speed of manufacturing the insulating glass units. These system improvements include manufacturing the edge seal as a metal re-enforced butyl strip (Tremco's Swiggle Seal®); roll forming the metal spacer and incorporating a butyl desiccant matrix and an outer butyl sealant (PPG's Intercept®); and manufacturing the spacer from EPDM foam with pre-applied butyl sealant and a desiccant matrix (AFG's Comfort Seal®). Although these improvements allow for the automated production of insulating glass units, residential sash windows still tend to be manufactured using largely manual assembly methods and typically, window frame fabrication is more labor intensive than sealed unit production.
One way of improving window assembly productivity is to fully integrate the frame and sealed unit assembly. In the presentation notes for the talk entitled Extreme Performance Warm-Edge Technology and Integrated IG/Window Production Systems given at InterGlass Metal '97, Glover describes a PVC sealed frame window system developed by Meeth Fenester in Germany. With this system, there is one continuous IG/window production line and using an automated four point welder, a PVC window frame is assembled around a double glazed unit. As noted in the paper, some of the concerns with the Meeth system include a problem of broken glass replacement, recycling/disposal of PVC window frames, and the technical risks of no drainage holes.
For window energy efficiency, most of the recent focus has been on improving the thermal performance of insulating glass units. Increasingly, it is being realized that substantial additional improvements will only be feasible through the development of new window frame types and technology. In a technical paper entitled Second Generation Super Windows and Total Solar Home Powered Heating, and presented at the Window Innovations '95 world conference in Toronto, Canada, Glover describes a second generation Super Window consisting of an exterior high performance triple glazed window and an interior high performance double glazed panel. By using motorized hardware, both the exterior and interior windows overlap the wall opening and this allows for a significant increase in solar gains and overall energy efficiency. However although significant energy efficiency improvements are achieved, the installation of the conventional casement window is very complex and this is primarily due to the extended width of the conventional window frame.
The present invention provides a fenestration sealed frame insulating glazing panel having an integral generally planar frame that is formed by a number of rigid plastic profiles having interconnected ends that define corners of the frame. The plastic profiles are fabricated of a material that has a low heat conductivity compared to aluminum and a coefficient of expansion that is similar to that of glass. Two glazing sheets are arranged in a spaced parallel relationship and attached to opposite sides of the frame to define therewith a sealed insulating cavity. Each framing profile in section has a portion that is overlapped by the sheets, and the overlapped portion of each framing profile defines on opposite sides thereof an elongated seat to receive a marginal edge region of a corresponding one of the glazing sheets. Each framing profile has a front face that is located between the elongated seats and is directed into the cavity. The glazing sheets are adhered to the seats by a structural sealant material that exhibits thermosetting properties. A low permeability sealant covers the front face of each of the frame profiles and extends towards the structural sealant on opposite sides of each framing profile to provide a continuous seal between the glazing sheets around the periphery of the cavity.
The low permeability sealant that is exposed to the interior of the cavity can incorporate desiccant material.
Preferably there is a decorative strip provided around the perimeter of each glazing sheet to cover or mask the structural sealant.
The rigid plastic profiles can be provided in many different forms, such as glass fiber filled thermoplastic extrusions, glass fiber pultrusions, glass fibre thermoplastic extrusions reinforced with thermoplastic pultruded strips, oriented thermoplastic extrusions, and structural thermoplastic foam extrusions. Whatever material is used in these rigid plastic profiles, it should have a heat conductivity that is low compared to aluminum. Preferably the heat conductivity would be less than {fraction (1/100)} that of aluminum. For example, whereas the thermal conductivity of aluminum is 160 W/m° C., the thermal conductivity of fibreglass is 0.3 W/m° C., and that of expanded polystyrene foam is 0.03 W/m° C.
A vapor barrier sheet film material can be applied to the front face of each framing profile, and the low permeability sealants may be hot melt butyl or polyisobutylene.
The structural sealant is preferably made from thermosetting silicone material, and an alternative preferred material option is for the structural sealant and the low permeability sealant to be a single material that has both thermoplastic and thermosetting properties, for example in modified silicone material or a reactive hot melt butyl material.
A third glazing sheet can be positioned between the two outer glazing sheets and this third glazing sheet which is the same shape but smaller in size than the outer glazing sheets. Typically, this third glazing sheet is directly adhered to a stepped frame profile.
The fenestration sealed frame insulating glazing panel of the invention may be utilized as a door or a window panel in an exterior building wall. Where the panel is mounted to be moveable, suitable operating devices are attached to the plastic frame for connection to an operating mechanism in the window or door frame in the building wall. When used as a window, one preferred option is for the glazing panel to be mounted in an overlapping relationship to an opening in the wall of the exterior side thereof.
In an alternative configuration the glazing panel in accordance with the invention may be utilized to provide ribbon windows in a building wall. In this arrangement, each panel is positioned so that it spans between top and bottom supports, the side edges of adjacent panels being in abutment but otherwise being unsupported.
The fenestration sealed frame glazing insulating panel of the present invention is self supporting and may be designed to carry structural loads, in this case the glazing sheets being made of laminated glass. In such a stressed skin structural panel, the glazing sheets are preferably spaced apart by at least 70 mm, and the panel can incorporate a passage through which air can enter and leave the interior cavity, such passage incorporating desiccant to remove moisture from air that enters the cavity between the sheets.
The following is a description by way of example of certain embodiments of the present invention, reference being made to the accompanying drawings, in which:
Referring to the drawings,
Although an entrance door is illustrated in
The glazing sheets 23, 24 and 25 are typically made from heat strengthened or tempered glass. For optimum thermal performance, the width of the glazing cavity spaces 41 and 42 between the glazing sheets 23, 24 and 25 is typically about 12.5 mm (½ inch ). For further improved energy efficiency, a low-e coating 51 can be applied to one or more of the glass cavity surfaces of the glazing panel 21. In addition, the cavity spaces 41 and 42 between the glazing sheets 23, 24 and 25 can accommodate a low conductive gas such as argon or krypton.
For triple-glazed panels, one major advantage of the stepped frame profile is improved condensation resistance. The bottom edge cold air convection currents 57 within the outer glazing cavity 41 do not coincide with the bottom edge cold air convection currents 58 within the inner glazing cavity 42. As a result, bottom edge glazing temperatures can be quite significantly increased.
The rigid plastic profiles 30 can be made from various materials using various different production processes. As illustrated in
An optional barrier film 34 is laminated to the stepped profiles 30, and this film 34 extends from the two top side edges 35 and 36 across the two front faces 37 and 38. The barrier film 34 is also laminated to a tongue shaped portion 39 located between the glazing sheets 24 and 25.
Low permeable sealant 40 is applied continuously to the barrier film 34 creating a continuous barrier of sealant material between the glazing sheets 23 and 24. This low permeable sealant 40 must be non-outgassing and preferred materials include hot melt butyl and polyisobutylene sealants. To remove moisture vapor from the glazing cavity spaces 41 and 42, the low permeable sealant incorporates desiccant fill material 61 with 3A molecular sieve desiccant being the preferred material.
The preferred material for the barrier film 34 is a saran-coated, metallized plastic film that is thermally bonded to the rigid plastic profile. The purpose of the barrier film 34 is to provide a secondary barrier for moisture protection and inert gas retention. However, the use of the barrier film is optional and, assuming that the low permeable sealant 40 can be consistently and accurately applied, there is no need for this secondary barrier protection.
The glazing sheets 23 and 24 are adhered to the framing profile 30 with structural thermosetting sealant 60 that is applied to the bottom portions 43 and 44 of the extended projection 45. Various thermosetting sealant materials can be used and because of proven durability, one preferred material is one or two part silicone sealant. The center glazing sheet 25 is held in position by means of a Z-shaped clip 46 that is held in position by the sealant material 33.
To hide the perimeter edge-seal, decorative plastic film strips 47 and 48 are applied to the perimeter edges 49 and 50 of the glazing sheets 23 and 24. Typically the decorative strips are made from dual tone material with the inner surface being colored black while the outer surface is typically white or another contrasting color.
An additional strip 52 is applied to the perimeter edge 53 of the center glazing sheet 25 and the outward surface is typically a dark color such as black. The top edge of the decorative strip 52 is lined up with the top edges of the outer decorative strips 47 and 48. When viewed at an oblique angle, the dark colored surfaces visually merge together creating the visual illusion of a solid profile and as a result, the stepped portion of the frame is not visually noticeable.
The decorative strips 47 and 48 can be made from various materials, and one preferred material option is polyethylene terephthalate (PET) plastic film that is double coated with fluoroelastomer paint. The strips 47 and 48 are adhered to the outer perimeter edges 49 and 50 of the glazing sheets 23 and 24 with acrylic pressure sensitive adhesive 56. A second preferred material option is to produce the strips from fluoro-elastomer coatings that are directly applied to the glass. For color matching, the exposed outer surfaces of the plastic profile 30 can also be coated with the same fluoro-elastomer coatings used for the strips.
For example, the center glazing sheet 25 is a rigid transparent plastic sheet 62. In comparison with conventional glass, the advantage of using a rigid plastic center glazing is that it provides for improved security protection and hurricane resistance. The plastic sheet can be made from various materials including polycarbonate and acrylic sheet.
The rigid plastic profiles 30 are made from a thermoplastic polyurethane glass fibre pultrusion 63 that is marketed by Dow Plastics under the trade name of Fulcrum. The glass fibre content of the thermoplastic pultruded material can be as high as 80 per cent. As a result, the material is very stiff and rigid with the coefficient of thermal expansion being very similar to that of glass. Hollow pultruded profiles 63 are connected together with corner keys and are thermally bonded at the corners to ensure a long term, durable seal. For improved thermal performance, the hollow profiles 63 are filled with low density insulating foam 72.
An optional barrier film 34 can be laminated and adhered to the hollow profile using pressure sensitive adhesives. Alternatively, the barrier film 34 can be applied during the pultrusion process, and this has an advantage in that the film can be coated with a thin layer of polyurethane material which helps ensure that the film cannot be accidentally damaged or punctured prior to the assembly of the sealed frame panel.
Instead of using a combination of thermoplastic and structural thermosetting sealant, a single thermoplastic/thermosetting sealant 64 can be used. The key advantage of using a single material is that automated sealant application is greatly simplified. With the stepped triple-glazed profile, the sealant is continuously applied from the bottom side edges 43 and 44, across the front faces 37 and 38 on the tongue portion 39. Various thermosetting/thermoplastic sealant materials can be used including reactive hot melt butyl, modified silicone, and modified polyurethane materials. In all three cases, the sealant is applied as a hot melt thermoplastic material, but over time, the sealant chemically cures as a thermosetting material. The sealant material incorporates desiccant fill material and one preferred material is Delchem D-2000 reactive hot melt butyl that is produced by Delchem of Wilmington, Del. To protect the sealant from direct UV exposure, silicone sealant beads 71 can be applied in the gaps 65 and 66 between the bottom glass edges and the framing profiles.
The decorative pattern strips 47 and 48 are located on the inner face of the glazing sheets 23 and 24. The decorative strips 47 and 48 are made from ceramic frit material that is bonded to the glass at high temperatures.
Although the perimeter frame is typically assembled from rigid plastic profiles, it can be appreciated by those skilled-in-the-art that the frame can also be manufactured as one piece using injection molding production processes. The main drawback is the high cost of the large molds which means in effect that only a very limited number of standard sizes can be cost effectively manufactured.
After the glazing sheets 23 and 24 have been accurately matched, the thermoplastic/thermosetting sealant is then fully wet out by applying heat and pressure to the sealant material. As well as wetting out the sealant, the heat and pressure also increases the structural bond strength and also initiates the curing process. Depending on the profile shape, either a conventional roller press can be used or alternatively the thermoplastic sealant can be wet out by means of pressure rollers that automatically move around the perimeter edge of the glazing sheets 23 and 24.
After the triple glazing panel has cooled down, the sealed cavities are filled with an inert gas, such as argon or krypton. Both the inner and outer fill holes through the hollow profile are plugged and typically, these plugs are made of thermoplastic material that can be thermally welded to the thermoplastic profile. Compared to a conventional window frame assembly, a key advantage of sealed frame construction is that for operable windows and doors, it is feasible for the panels to be easily refilled on site so there is no thermal performance degradation due to long term gas loss.
For fabricating the perimeter rigid frame profiles, various other plastic materials and production processes can be used. As shown in
Compared to aluminum and other metals, the four alternative plastic materials have comparatively low thermal conductivities. For example in the case of fibreglass, the thermal conductivity is 0.3 W/m° C. while in comparison the thermal conductivity of aluminum is 160 W/m° C. However, compared to fiber glass pultrusions, the thermal conductivity of other plastic materials is much lower. For example, the thermal conductivity of expanded polystyrene foam is 0.03 W/m° C.
Also, the four alternative plastic materials have a coefficient of expansion somewhat similar to glass and this helps ensure that there is minimum differential expansion between the glass sheets and the rigid plastic profiles.
Particularly for overlap casement windows, sealed frame construction offers the advantage that panel width can be reduced and as a result, the overlap window can have a similar width to the outer rigid foam wall insulation. This greatly helps to simplify installation and allows the insulated wall to be sandwiched between the inner and outer frames. As a result, energy efficiency is increased and solar gains are maximized. For example, according to the Canadian energy rating system, a conventional double glazed window can have an ER minus 25 rating, while a high performance double, single overlap window can have an ER plus 25 rating.
The hardware can be operated manually or by means of a single electrical motor.
A flat rigid outer profile 106 is snap fitted to the casement sash frame 128.1 creating a window hardware chamber 108. The outer rain screen weather stripping 105 is also attached to the bottom end 109 of the rigid profile 106. The top end 111 of the rigid profile is a decorative feature that overlaps and hides the perimeter edge seal 118. The rigid profile can be made from a variety of materials including aluminum and pultruded fiberglass.
The main air barrier seal is a conventional EPDM rubber gasket 112. The outer window frame 110 is made from conventional PVC plastic extrusions that are thermally welded at the corners. The outer PVC frame 110 is directly screw fixed to the wood framing member 114 that forms part of the insulated wall construction 115. The bottom leg 104 of the PVC window frame 110 extends outwards for a minimum of 50 mm and is overlapped by the rigid foam insulation 117.
In addition to residential windows and doors, sealed-frame construction also offers advantages for commercial building fenestration systems.
Even though a 50 mm wide stressed skin glass panel is comparatively stiff, especially when fabricated with rigid fibreglass profiles 124, the maximum span of the panel between the top and bottom supports 122 and 123 is about 1.5 m with the maximum spacing being dependent on such factors as local wind exposure, glass thickness and panel size.
To provide the required structural stiffness, the glazing sheets, 23 and 24 are spaced apart a minimum of 70 mm and preferably at least 100 mm with the spacing varying depending on the sunroom geometry, building size, panel size and local climatic conditions such as winter snow and ice loads.
In designing the glass stressed skin structure, there is a need for some structural redundancy so that if a single glass sheet randomly shatters or breaks, there is no catastrophic structural failure. Consequently, as shown in
For optimum thermal performance of a conventional double glazed insulating glass unit, glazing sheets are spaced about 12 to 15 mm apart because if the glazing sheets are spaced wider apart, there is increased convection flow within the glazing unit and thermal performance is downgraded. One way of dampening convection flow and increasing energy efficiency is through the use of honeycomb convection suppression devices. One preferred convection suppression device 141 is manufactured by Advanced Glazings of Sydney, Nova Scotia. The product is marketed under the name InsolCore.® The product is made from flexible polypropylene plastic film that is heat welded together to form a honeycomb convection suppression device that is suspended between the two glazing sheets.
The front face of the profile is coated with low permeable, desiccant filled sealant material. An alternative option is to laminate flat strips of impervious gas/moisture barrier material to the front face of the rigid profile and then continuously overlap these flat strips at the side edges and corners with the same low permeable sealant that is also applied to the side edges.
The two panels 131A and 131B are spaced about 9 mm apart. Both the interior and exterior joints are sealed with silicone sealant 119. Flexible foam strips 143 are attached to both center tongues 144 of the E-shaped profiles 142 creating two separate cavity spaces 145 and 146.
It should be understood that for purposes of clarity, certain features of the invention have been described in the context of separate embodiments. However, these features may also be provided in combination in a single embodiment. Furthermore, various features of the invention which for purposes of brevity are described in the context of a single embodiment may also be provided separately or in any suitable sub-combination in other embodiments.
Moreover, although particular embodiments of the invention have been described and illustrated herein, it will be recognized that modifications and variations may readily occur to those skilled in the art, and consequently it is intended that the claims appended hereto be interpreted to cover all such modifications and equivalents
This is a continuation application of Ser. No. 10/089,726, filed Apr. 4, 2002, now abandoned, which is a National Stage of International Application No. PCT/CA00/01180, filed Oct. 6, 2000.
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| Number | Date | Country | |
|---|---|---|---|
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 10089726 | US | |
| Child | 10852100 | US |
