GB2523638A

GB2523638A - Fenestration unit and composite for same

Info

Publication number: GB2523638A
Application number: GB1500459.1A
Authority: GB
Inventors: Lennart Johnson; Mark Wheatley; Mark Cocker
Original assignee: SENIOR ARCHITECTURAL SYSTEMS Ltd
Current assignee: SENIOR ARCHITECTURAL SYSTEMS Ltd
Priority date: 2014-01-10
Filing date: 2015-01-12
Publication date: 2015-09-02
Anticipated expiration: 2035-01-12
Also published as: GB201500459D0; GB201400420D0; GB2523638B

Abstract

Composite for use as a frame section 100A, 100B in a fenestration unit 200, comprising inner 102 and outer 104 members and an intermediate thermal break 106 arranged between them. The thermal break being polyurethane foam, with a density between 160kg/m3 and 250kg/m3, integrally connected to the inner and outer members. The inner and outer members may be made of aluminium, bronze, fibreglass, PVCu, steel or wood. Also claimed is a method of producing the composite by placing inner and outer members spaced apart in a mould (300, Figs. 3-7) and casting and curing an expandable polyurethane foam (105, Fig. 6) within the mould. The mould may comprise fist and second parts (302 and 304, Figs. 3-7) to clamp the inner and outer members against movement and opposing sealing elements (310, Figs. 3-7) to prevent foam egress. The method may involve heating the mould before casting and/or during curing.

Description

Fenestration unit and composite for same The present invention relates to a composite for use in the framework of a fenestration assembly, such as a glazed window, facade or door.

The thermal performance of fenestration assemblies, such as glazed doors, facades and windows, is often of critical importance to the energy efficiency of a building. Building regulations require such fenestration assemblies to include a thermal break for preventing thermal transfer between an interior and exterior of the assembly, and various thermal break solutions are known.

Economic pressures within the buildings and construction industries drive the need for further improvements, not only in thermal performance. but also in materials and manufacturing costs.

The invention seeks to provide an improved composite for use in (he framework of a fenestration assembly, such as a glazed window, facade or door.

According to a first aspect of the invention, there is provided a composite for use as a frame section in a fenestration unit, the composite comprising an inner member intended to he arranged to face inwardly of a building, an outer member intended to be arranged to face outwardly of a building; wherein the composile comprises an intermediate member arranged between the inner and outer members, the intermediate member being in the form of a casting used to connect the inner and outer members, and the intermediate member defining a thermal break between the inner and outer members, wherein the intermediate member takes the form of a polyurethane foam having a density in the range of lôOkg/m3 -250kg/m3.

The foam is selected to have a low density after casting, e.g. to provide excellent u values.

The applicant has found that using a foam with a density in this range gives a particularly low u value. Selecting a low density foam in this range also means that less chemicals need to be used to fill the space compared to when a higher density foam is used. This is because a higher density foam will only expand to about 3 times its volume from liquid, whereas a lower density foam, such as one in the range above, will expand to about 5 times its volume from liquid. It is clear that using a lower quantity of chemicals is beneficial, both in terms of the cost of manufacture and the environmental impact.

The inner and outer members may each be fabricated from one of the following materials: aluminium, bronze. fihregass. PVCu. steel or wood.

The intermediate member may be of rigid, self-supporting configuration.

The intermediate member may define a structural element between the inner and outer members.

The thermal break may have a planar upper surface.

The thermal break may have a density after casting in the range of 180 kg/rn3 -220 kg/m3, e.g. substantially in the region of 200 kg/m3.

According to a second aspect of the invention, there is provided a fenestration assembly incorporating a composite in accordance with the first aspect of the invention.

According to a third aspect of the invention, there is provided a method for producing a composite frame section for a fenestration unit, the composite frame section comprising an inner member, an outer member, and a thermal break arranged between the inner and outer members, the thermal break having a density after casting in the range of lôOkg/m3 - 250kg/rn3, the method comprising the steps of placing the inner and outer members in a mould apart from one another so as to define a spacing therebetween. casting an expanding polyurethane foam in the spacing, and curing the foam in the mould in order to produce a composite frame section comprising the thermal break integrally connected between the inner and outer members.

The mould may define an enclosure comprising first and second mould parts intended to clamp the inner and outer members against movement during casting of the thermal break.

The mould may include opposing sealing elements intended to be clamped against the inner and outer members and bridge the gap therebetween, for sealing against foam egress and preventing contact between the foam and the mould.

The sealing element may comprise silicon rubber, arranged for defining a surface finish of the thermal break.

The mould maybe heated prior to introduction of the foam into said spacing.

The mould may be held under heated conditions during curing of the foam in the mould.

The inner and outer members may each he fabricated from one of the following materials: aluniinium, bronze, fibreglass, PVCu, steel or wood.

According to a fourth aspect of the invention, a composite frame section is provided, the composite frame section being made in accordance with the method of the second aspect of the invention.

According to a fifth aspect of the invention, a fenestration assembly is provided, the fenestration assembly incorporating a composite frame section made in accordance with the method ol the second aspect of (he invention.

According to a sixth aspect of the invention, there is provided a fenestration assembly comprising a frame and glazing, wherein the frame comprises a composite structural section formed from an inner member, an outer member, and a thermal break arranged between the inner and outer members, wherein the theimal break takes the form of a casting of polyurethane foam integrally connected to the inner and outer members, wherein the thermal break has a density after casting in the range of l6Okg/m3 -250kg/rn3.

The thermal break has a density after casting in the range of 180 kg/rn3 -220 kg/rn3, e.g. substantially in the region of 200 kg/rn3.

According to a seventh aspect of the invention, there is provided a method for producing a cornposite frame section for a fenestration unit, the composite frarne section comprising an inner member, an outer member, and a thermal break arranged between the inner and outer members, the method comprising the steps of paeing the inner and outer members in a mould apart frorn one another so as to define a spacing therebetween, casting an expanding polyurethane foam in the spacing, and curing the foam in the mould in order to produce a cornposite frarne section cornprising the thermal break integrally connected between the inner and outer members.

The mould may include opposing sealing elements intended to he clamped against the inner and outer members and bridge the gap therebetween. for sealing against foam egress and preventing contact between the foam and the mould.

The sealing elements may comprise silicon rubber, arranged for defining a surface finish of the thermal break.

The mould maybe heated prior to introduction of the loam into said spacing.

The inner and outer memhers may each he fabricated from one of the following materials: aluminium, bronze, fibreglass, PVCu, steel or wood.

The thermal break may have a density after casting in the range of 150 kg/rn3 -300 kg/m3.

more preferably in the range 180 kg/m3 -220 kg/m3, e.g. substantially in the region of 200 kg/rn3.

According to an eighth aspect of the invention, there is provided a coniposite frame section made in accordance with the seventh aspect of the invention.

According to a ninth aspect of (he invention, there is provided a fenestration assembly incorporating a composite section made in accordance with the seventh aspect of the invention.

According to a tenth aspect of the invention, there is provided a composite for use as a frame section in a fenestration unit, the composite comprising an inner member intended to be arranged to face inwardly of a building, an outer member intended to be arranged to face outwardly of a building. wherein the inner and outer members are each fabricated from one of the following materials: aluminium, bronze. fibreglass, PVCu. steel or wood; further wherein the composite comprises an intermediate member arranged between the inner and outer members, and which defines a thermal break between the inner and outer members and members, wherein the intermediate member takes the form of a polyurethane foam having a density in the range of lSOkg/m3 -300kg/m3.

The intermediate member may take the form of casting used to connect the inner and outer members.

The intermediate member may be of rigid, self-supporting configuration.

The thermal break may have a planar upper surface.

According to an eleventh aspect of the invention, there is provided a fenestration assembly incorporating a composite in accordance with the tenth aspect of the invention.

According to a twelfth aspect of the invention, there is provided a fenestration assembly comprising a frame and glazing, wherein the frame comprises a composite structural section formed from an inner member, an outer member, and a thenmil break arranged between the inner and outer menThers, wherein the thermal break takes the form of a casting of polyurethane foam integrally connected to the inner and outer members.

The thermal break may have a density after casting in the range of 150 kg/rn3 -300 kg/m3, more preferably in the range 180 kg/rn3 -220kg/rn3, e.g. substantially in the region of 200 kg/m3.

Other aspects, advantages and features of the invention will now be described, by way of example, with reference to the accompanying drawings. in which: Figure 1 is a schematic cross-section through a composite frame section for a fenestration assembly; Figure 2 is a schematic cross-section through a fenestration assembly incorporating a composite frame section substantially the same as the composite shown in Figure 1; Figures 3 to 7 are similar to Figure 1, showing various stages of a production method for the composite frame section of Figure 1; and Figure 8 and 9 are simflar to Figure 2, showing fenestration assernhlies incorporating alternative embodiments of composite frame section.

Referring firstly to Figure 1. a composite for use in a fenestration assembly is indicated generally at 100. The composite 100 is deflned by an inner member 102 intended to he arranged to face inwardly of a building, an outer member 104 intended to be arranged to face outwardly of a building, and an intermediate member 106 arranged between the inner and outer members 102, 104.

The intermediate member 106 is designed to define a thermal break between the inner and outer members 102. 104. More particularly, the intermediate member 106 takes the form of a casting of polyurethane foam.

In exemplary embodiments, the foam is selected to have a low density after casting, e.g. to provide excellent u values. In exemplary embodiments, the foam is selected and configured so that it has a density in the range of 160 kg/ni3 -250 kg/rn3 after casting. The applicant has found that using a foam with a density in this range gives a particularly low u value. Even more preferably, the density after casting is in the range 180 kg/rn3 -220 kg/m3. e.g. substantially in the region of 200 kg/rn3. Selecting a low density foam in this range also means that kss chemicals need to be used to fill the space compared to when a higher density foam is used. This is because a higher density foam will only expand to about 3 times its volume from liquid, whereas a lower density foam, such as one in the range above, will expand to about 5 times its volume from liquid. It is clear that using a lower quantity of chemicals is beneficial, both in terms of the cost of manufacture and the environrnental impact.

The foam preferably has a closed cell structure, and so is not adversely affected by water or moisture, and thereby avoids the need for a coating.

A suitable polyurethane foam resin material can be obtained from Azon UK Limited (Product name SPF 10-35-BLK-D). In practice, this is mixed with a catalyst (e.g. Product name 13- 302A EU from Azon UK Limited). in order to create an expanding foam material for the production process of the composite 100 (as described in more detail below).

As will he described in more detail below, the intermediate member 106 is cast between the inner and outer rnembers 102, 104, so as to becorne integrally linked between the inner and outer members 102, 104.

As can he seen in Figure 1, the intermediate member or thermal break 106 has upper and lower surfaces 108. 110 which are planar; in this embodiment, parallel with one another.

The intermediate member 106 is of rigid, self-supporting configuration, and defines a structural element between the inner and outer members 102, 104.

The composite 100 of Figure 1 obviates the need for any other forrn of tie or reinforcement.

between the inner and outer members 102, 104. The thermal break material forms the bond between the inner and outer skins' of the composite. The number of components is minimaL and fabrication complexity is reduced, compared with many other solutions that are available on the market.

Figure 2 shows part of a fenestration assembly 200 having a frame 202 and glazing 204. The frame 202 incorporates two composites bOA, bOB, substantially the same as the composite of Figure 1, mounted one above another. It can be seen that the inner awl outer members 102, 104 of the composites bOA, IOOB include flanges, projections or upstands which enable the composites bOA, 100B to be interconnected with one another and/or with other aspects of the frame 202. Also, the planar upper and lower surfaces of the composite frame section IOOB are not parallel. However, the general construction of the cornpositc frame sections bOA, 100B is otherwise substantially the same as for the composite 100 of Figure 1, i.e. wherein the thermal break 106 takes the form of a casting of polyurethane foam integrally connected to the inner and outer members 102, 104, with a density after casting in the range of 160 kg/rn3 -250 kg/rn3, more preferably in the range 180 kg/rn3 -220 kg/rn3, e.g. substantially in the region of 200 kg/ni3.

A seal 206 is mounted between the frame 202 and glazing 204, and to seal the frame 202 to glazing 204, and minimise vibration between frame 202 and glazing 204. Spacers 208 are mounted between the glazing panes 210, 212, in order to maintain the g'azing panes 210, 212 at a desired spacing from one another. A glazing wedge 214 is provided between the inner glazing pane 212 and the frame 202.

A thermal break bead 216 is arnmged between the glazing 204 and an upper surface of the uppermost composite frame section bOB.

Use of composites bOA, IOOB having a low density thermal break between integrally connected inner and outer members in fenestration assemblies such as illustrated in Figure 2 has been found to provide high theimally efficiency and cost-effectiveness.

There now follows a description of an example method for making a composite frame section of the kind referred to above, with reference to Figures 3 to 7.

In general terms, the inner and outer members 102, 104 are placed in an enclosed mould 300, and an expanding polyurethane foam material is used to form a thermal break 106 between the inner and outer members 102, 104.

In the exemplary method shown in Figures 3 to 7. the mould 300 consists of two parts 302, 304, which fit together to define an enclosed mould cavity.

Starting with Figure 3. (he inner and outer members 102, 104 are placed in the first mould part 302 at a spacing 306 from one another.

The mould parts 302, 304 include complimentary snap-fit formations 308, which enable the two mould parts 302, 304 to he snap-fitted together. The second mould part 304 is placed over the first mould part 302, in order to enclose the inner and outer members 102, 104 and the spacing 306. e.g. as shown in Figure 4. The two mould parts 302, 304 are then brought further together until the snap-fit formations engage in a snap-fitting connection, as shown in Figure 5, uniting the two mould parts 302, 304.

As can be seen clearly in Figures 3 to 5, each mould part 302, 304 includes a silicon rubber element 310, which is clamped against the respective inner and outer members 102, 104, when the two mould parts are snap-fittingly connected. This secures the inner and outer members 102, 104 against movement. In addition, the sihcon rubber elements 310 are arranged to bridge the spacing 306 and thereby define the upper and lower limits of the region into which the thermal break is to be provided.

As can be seen from Figure 6, expanding polyurethane foam material 105 is then introduced into the spacing 306 in liquid form, e.g. through one or more ports (not shown) in the mould 300. A port may be provided in one or each of the longitudinal ends of the mould 300. and/or one or more ports may he provided along the length ci the mould 300. The nature of the liquid foam material 105 means that it soon expands to fill the spacing 306. The clamping force between the silicon elements 310 and the inner and outer members 102, 104 prevents egress of the foam liquid from the spacing 306. The snap-fitting connection between the mould parts 302, 304 resists expansion forces to prevent the mould parts becoming disengaged from one another.

The inner and outer members 102, 104 each include at least. one key 114 projecting into the spacing 306, and onto which the foam may obtain a purchase as it expands to fill the spacing 306, e.g. as shown in Figure 7.

In exemplary embodiments, the mould 300 is heated prior to injection of the foam into said spacing 306, e.g. to a temperature in the range 70-80 degrees Celsius. This has been found to promote expansion of the foam and minimise the risk of voids, to ensure optimum density of the thermal break 106. In exemplary embodiments, the mould 300 is held under heated conditions during the expansion stage of the process, e.g. for a predetermined period of time.

The mould 300 then undergoes a curng stage, for curing the expanded foam 106 in the mould 300. In exemplary embodiments, the mould 300 is held under heated conditions for a predetermined period of time dunng the cunng stage, to prevent rapid cooling of the thermal break material 106. Typically, the curing stage will take place at a lower temperature than the expansion stage, e.g. at 40-50 degrees Celsius.

After the curing stage, the two mould parts 302, 304 can be separated and the composite 100 is removed from the mould 300. The silicon rubber elements 310 of the mould 300 assist in producing the planar upper and lower surface finishes 108, 110 of the thermal break 106.

They also prevent the foam material 106 from adhering to the mould cavity, promoting easy release of the composite 100 from the mould 300 after the curing stage, and re-use of the mould 300 for subsequent production cycles.

In exemplary embodiments, the mould cavity is configured so that the expanding foam material does not achieve a free nse within the spacing 306, thereby increasing the overall density of the thermal break 106 beyond the free rise characteristics of the expanding foam material. This can be tuned to provide a desired low density for the thermal break 106, i.e. to provide a density alter casting in the range ol 160 kg/rn3 -250 kg/rn3. more prelerably in the range 180 kg/m3 -220 kg/in3, e.g. substantially in the region of 200 kg/m3.

The above method has been found to be very cost-effective.

In other embodiments, alternative means for preventing foam egress and adherence to the mould cavity. For example, elements coated with Teflon or silicon, greaseproof paper or the like, or silicon foam elements may be used, wherein the alternative means is used to bridge the gap between the inner and outer members, and to he clamped against the inner and outer members.

In exemplary embodiments, the mould 300 is placed on a conveyor and conveyed through an oven or conveyed past a suitable mould heating appliance, in order to pre-heat the mould 300 to a desired temperature prior to introduction of the expanding foam material. A conveyor (e.g. the same conveyor as for the pre-heating stage) may be used to convey the mould through an oven or to convey the mould past a suitable mould heating appliance, in order to maintain the mould at a desired curing temperature. A cooling stage may be preferred immediately prior to the curing stage, e.g. to bring the mould down to the desired cunng temperature from the elevated temperature of the foam introduction stage of the process.

One end of the mould 300 may be elevated prior to or immediately after introduction of the expanding foam material, in order to promote a flow of the expanding foam material along the spacing 306 between the inner and outer members 102, 104 along the length of the section. particularly if one or more end ports arc used for introduction of the liquid foam material. The mould may then be returned to a horizontal alignment (e.g. after a predetermined period of time) for the curing stage.

In exemplary embodiments, the inner and outer members 102, 104 may each he fabricated from one of the following materials: aluminium. bronLe, fibreglass. PVCu, steel or wood.

Where one of more of the members 102, 104 is made from wood, it may he necessary to introduce an interface material 116 between the thermal break and the wood member, in order to minimise the risk of heat from the foam causing evaporation of moisture in the timber. The interface material may take the form of a lacquer or other coating for the exposed end of the wooden member (e.g. as shown in Figure 8) or a separate element which is alTixed to cover the exposed end of the wooden member (e.g. as shown in Figure 9). The separate element 116 may take the form of a metal or PVC plate, for example. The plate 116 or the timber interface may be formed with a key or recess, e.g. of the kind illustrated as part of the inner and outer members in Figures 3 to 7, suitable to ensure bonding or purchase between the foam and the interface.