GB2247040A

GB2247040A - Glazing panels and materials

Info

Publication number: GB2247040A
Application number: GB9017787A
Authority: GB
Inventors: David John Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-08-14
Filing date: 1990-08-14
Publication date: 1992-02-19
Anticipated expiration: 2010-08-14
Also published as: GB9017787D0; GB2247040B

Abstract

A glazing panel or material comprising at least two spaced layers 4, 6 of relatively transmissive material and a layer 12 of relatively reflective and/or absorbent material between the, or two of the, layers. As shown. it is preferred that the two panes are of plastics and connected by webs 8, the layer 12 being provided by plastics film, mesh or perforated sheet, optionally coated eg with metal. A method of inserting such a film into the box sections comprises applying a partial vacuum at one end and pushing the strip into the other. <IMAGE>

Description

GLAZING PANELS AND MATERIALS This invention relates to glazing panels or materials.

High temperatures and glare caused by solar heat are major problems in conservatories in summer, spring and autumn.

In accordance with one aspect of the invention there is provided a glazing panel or material comprising at least two spaced layers of relatively transmissive material and a layer of relatively reflective and/or absorbent material between the, or two of the, layers.

One embodiment of the invention is a double or triple glazing panel in which the relatively transmissive material is glass.

Plastic roof glazing materials based on single, double or triple box sections are increasingly being used because they are lightweight, which means that the structure of the conservatory can be made less robust than would be the case with glass, leading to significant savings and a lower market cost. The cost of a conservatory based on plastic roof glazing materials is significantly less than an equivalent one in glass.

Plastic roof materials are translucent and let in the sun's heat just like glass causing heat and glare problems. The roof glazing is the main problem area with most conservatories because the sun shines on it virtually all day. As a result, typically up to 70% of all heat entering the conservatory enters through the roof. In winter the roof is the single most significant source of heat loss. It can be readily understood that most of the problems caused by conservatories can be eliminated by dealing with the roof so that it is insulated against the sun's heat in summer and against internal heat loss in winter.

Plastic roof glazing sometimes incorporates tint which does little to reduce temperatures. Laminates based on metalized polyester film with aluminium or other reflective metals can be affixed to the inner surface of the plastic roof glazing to reflect the suns heat away from the conservatory, to reduce winter heat loss and eliminate glare. These can be difficult to apply satisfactorily due to the ribbed nature of the surface and differential expansion and contraction which can cause wrinkling of the material. Also certain grades of plastics cause deterioration of the adhesive on the laminate and it peels away with time.

The lamination process is time consuming and involves the use of water and surfactants which demand skilful personnel and in some cases make it arduous.

In another embodiment of the invention, the relatively transmissive material is plastics comprising two or more layers spaced apart by a plurality of spaced webs defining one or more layers of box sections and including a strip of relatively reflecting and/or absorbent material in some or all of the box sections.

In a material including three or more layers of box sections, the strips of relatively reflecting and/or absorbent material are preferably in an outermost layer of box sections.

The relatively reflecting and/or absorbent material preferably comprises metalized plastics. It is possible to produce such a plastic glazing which has a performance equal to that of high performance solar glass.

The plastics material is preferably polyester. The metal layer on the plastics material may be coated with lacquer or plastic.

In other embodiments the layer of relatively reflective and/or absorbent material comprises a mesh or a perforated sheet.

The layer of relatively reflective and/or absorbent material may be metallic. The metallic layer may be polished aluminium, stainless steel, or titanium. The metallic layer may be plated with chromium, gold, silver, zinc or cadmium. The metallic layer may be polished and coated with a transparent coating.

In another aspect, the invention extends to a method of manufacturing a roof glazing material comprising feeding a strip of relatively reflecting and/or absorbent material into some or all box sections of a relatively transmissive plastics sheet defining one or more layers of box sections. The method may be performed in a factory, on site or, in some cases, in situ.

The strip is preferably fed into the box section by applying a partial vacuum to one end of a thin tube, contacting the other end of the tube with the strip adjacent its end so that it is held on the end by air pressure, pushing or drawing the strip into the box section and releasing the partial vacuum.

Alternatively, the strips may be attached to a plug which is then rammed down the box section or the strips may be blown down the box section with compressed air, or sucked up the box section by drawing a vacuum. The strips may be attached to the end of a rod by a grip, pushed down or pulled up the box section and released.

Whatever system is used a plurality of strips is preferably placed simultaneously.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an end view of a single box section glazing sheet embodying the invention; Figure 2 is an end view of a double box section glazing sheet embodying the invention; and Figure 3 is an end view of a triple box section glazing sheet embodying the invention.

Referring to the drawings, a plastic roof glazing sheet 2, has two layers 4,6 of relatively transmissive (normally clear) material. Commonly the relatively transmissive material is polycarbonate. The layers 4,6 are spaced apart by integral webs 8 of the same material. Although shown schematically plane, the outer surfaces of the layers 4 and 6 are normally somewhat ribbed.

As can be seen the construction produces a series of side by side box sections 10.

In order to improve the heat reflecting performance of the glazing sheet, a layer of relatively reflective and/or absorbent material is positioned between the layers 4 and 6. In the embodiment illustrated a strip 12 of metalized plastics, e.g- polyester, is placed in each box section 10. Such material is normally partly reflective and if placed in every box section 10, produces a performance equal to that of high performance solar glass. Especially if the strips 12 are highly, or completely, reflecting it may be desirable to leave some of the box sections empty, e.g. alternately or one in three.

Alternative or additional to metalizing, the material may be tinted to provide light and/or heat absorbing properties.

Normally, the metalized layer is between two layers of plastics.

To provide greater reflectivity, one layer of plastics material may be metalized on both sides. The metal layers may be protected, e.g. by two outer layers of plastics, e.g. polyester or polythene, or by lacquers which latter would give low emissivity properties and high summer and winter insulation performance. The material may have one metal layer and one tinted layer, in which case the tinted layer is preferably used on the inside and the metalized layer on the outside for reflection. The material may be provided with a much heavier tint than is available in conventional plastic roof glazing.

The embodiment illustrated in Figure 2 includes a further layer 13 spaced from the layer 6 by further integral webs 20. This improves its strength and thermal insulating properties. The sheet is preferably used with the strips 12 in the box sections 10 on the outside.

The embodiment illustrated in Figure 3, includes a further layer 22 spaced from the layer 18 by integral webs 24 so that the strips of metalized plastic 12 are in an outer layer of box sections 10. The sheet is preferably used with this layer to the outside.

In order to manufacture the sheet illustrated in any of Figures 1 to 3, a film of metalized p'astics material is cut into strips of appropriate width. A thin tube is connected to a suitable vacuum pump to draw a vacuum in the tube. The other end of the tube is placed on an end of one of the strips which is held thereon by air pressure. The tube is then pushed down a box section taking the strip with it. Alternatively, the tube may first be pushed down the box section, the vacuum drawn to attach the strip, and then pulled back up the box section drawing the strip with it.

The tube may have a sucker cup at its free end.

The strips may be placed in the box sections as a factory manufacturing step, on the building site, or in situ after the building has been glazed.

In an alternative embodiment, not illustrated, the layer of metalized plastic is present between two layers of glass in a double or triple glazing panel.

In other alternatives, the relatively reflective and/or absorbent layer is metallic. Suitable examples are polished aluminium, stainless steel or titanium. Other metals may be plated for example with chromium, gold, silver, zinc or cadmium. In yet other examples other metals may be given a transparent top coat eg a lacquer. As explained above, strips of such materials may be placed in some, though not all, of the box sections.

Alternatively, or additionally, the materials may be in the form of a mesh, eg expanded metal, or may be perforated.

Opaque unpolished materials could be used, but polished materials perform better.

Claims

1. A glazing panel or material comprising at least two spaced layers of relatively transmissive material and a layer of relatively reflective and/or absorbent material between the, or two of the, layers.

2. A glazing panel as claimed in Claim 1, comprising a double or triple glazing panel in which the relatively transmissive material is glass.

3. A glazing panel or material as claimed in Claim 1, in which the relatively transmissive material is plastics comprising two or more layers spaced apart by a plurality of spaced webs defining one or more layers of box sections and including a strip of relatively reflective and/or absorbent material in some or all of the box sections.

4. A glazing panel or material as claimed in Claim 3, including three or more layers of box sections in which the strips of relatively reflective and/or absorbent material are in an outermost layer of box sections.

5. A glazing panel or material as claimed in any preceding Claim, wherein the layer strip of relatively reflecting and/or absorbent material comprises metallized plastics.

6. A glazing panel or material as claimed in Claim 5, wherein the plastics material is a polyester.

7. A glazing panel or material as claimed in Claim 5 or 6, wherein the metal layer on the plastics material is coated with lacquer or plastic.

8. A glazing panel or material as claimed in any of claims 1 to 4, wherein the layer of relatively reflective and/or absorbent material comprises a mesh or a perforated sheet.

9. A glazing panel or material as claimed in any of claims 1 to 4 or 8, wherein the layer of relatively reflective and/or absorbent material is metallic.

10. A glazing panel or material as claimed in claim 9, wherein the metallic layer is polished aluminium, stainless steel, or titanium.

11. A glazing panel or material as claimed in claim 9, wherein the metallic layer is plated with chromium, gold, silver, zinc or cadmium.

12. A glazing panel or material as claimed in claim 9, wherein the metallic layer is polished and coated with a transparent coating.

13. A method of manufacturing a roof glazing material comprising feeding a strip of relatively reflective and/or absorbent material into some or all box sections of a relatively transmissive plastics sheet defining one or more layers of box sections.

14. A method as claimed in Claim 13, wherein the strip is fed into the box section by applying a partial vacuum to one end of a thin tube, contacting the other end of the tube with the strip so that it is held on the end by air pressure, pushing or drawing the strip into the box section and releasing the partial vacuum.