GB1579726A

GB1579726A - Multiple glazing

Info

Publication number: GB1579726A
Application number: GB3504476A
Authority: GB
Original assignee: Pilkington Brothers Ltd
Current assignee: Pilkington Group Ltd
Priority date: 1977-08-23
Filing date: 1977-08-23
Publication date: 1980-11-26

Description

(54) IMPROVEMENTS IN OR RELATING TO MULTIPLE GLAZING (71) We, PILKINGTON BROTHERS LIMITED, a Company incorporated under the laws of Great Britain of Prescot Road, St.

Helens, Merseyside, WA10 3TT, England, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to multiple glazing units and in particular to sealed multiple glazing units having a wide air space and to spacer elements for use in the construction of such units.

The spaces between adjacent panes of multiple glazing units are generally referred to as air spaces, although they may, if desired, be filled with a gas other than air, for example a gas which provides the unit with improved thermal or acoustic insulation. Thus the use of the term "air space" to refer to a space between adjacent panes of a multiple glazing unit does not necessarily imply that the space is filled with air. It is common practice to refer to the perpendicular distance between the panes as the dimension of the air space. Sealed double glazing units commonly have air spaces in the range 5 to 12 mm and sealed units having a wide air space, for example an air space of 15 mm or more, have not generally been available, although the wider air spaces have the advantage of providing increased acoustic insulation.

One problem with sealed units of wide air space arises from pressure differentials between the gas in the air space and the outside atmosphere. These differentials arise from variation in pressure in the outside atmosphere and from temperature changes which result in variations in the pressure of the gas in the air space of the unit. It will be appreciated that, with wide air space units, the pressure differentials lead to a greater strain on the spacing and sealing system than with units of narrow air space. To withstand the pressure differentials it is convenient to use at least one pane which is capable of flexing, for example a pane of toughened glass. The flexing of one or both panes of a sealed multiple glazing units of wide air space imposes especially heavy demands on the spacing and sealing system used in the unit. These demands are particularly severe when the units are to be used for glazing railway carriage windows, since these windows are subject to abrup pressure changes when the carriages enter and leave tunnels or pass one another at high speed.

We have found that a spacer element constituted by a hollow section of flexible, nonbrittle material including at least one reinforcing rib extending across the cavity may be used to provide the combination of strength and flexibility required to accommodate the pressure differentials referred to above.

According to the present invention there is provided a spacer element for use in the construction of a sealed multiple glazing unit of wide air space said spacer element being constituted by a hollow section of flexible, nonbrittle material including first and second side walls and upper and lower walls extending between said side walls, the outer faces of said side walls being parallel and spaced apart at least 15 mm for locating first and second panes of glazing material in parallel spaced relationship, said hollow section including at least one reinforcing rib extending across the cavity in the hollow section.

The spacer element of the present invention is made of a flexible, non-brittle material to provide the edges of the unit with some flexibility so that the panes can flex under load without rupturing the seal around the edges of the unit. We have found that lead is a suitable material although other suitable materials, for example, plastics materials or metal alloys of similar ductility for example alloys of lead, ma) be used.

The hollow section of the spacer element is preferably, but not necessarily, rectangular in form with at least one reinforcing rib extending across the cavity within the section. The spacer element may be made, for example, by extruding the flexible, non-brittle material. The spacer section, including any reinforcing ribs, is of integral construction. It is preferably formed initially as a single unit, for example by extrusion, although it may be formed by directly securing together two or more component parts thereof. Thus, for example, two separate rectangular sections may be rigidly secured together in side-by-side relationship with adhesive between adjacent faces to form a spacer element in accordance with the present invention.

The reinforcing rib is required to provide the hollow spacer element with sufficient rigidity, despite the flexible, non-brittle nature of the material from which it is made, to satisfactorily withstand the fluctuating loads to which the spacer will be subjected in use.

We have found that a rib disposed parallel to the outer faces of the side walls of the hollow section, (the walls against which the glazing material is located in use) and extending between the upper and lower walls of the section is very effective in reinforcing the hollow section for use as a spacer, Moreover, such a reinforcing rib assists in avoiding flattening of the hollow section which tends to occur if the section is bent about an axis perpendicular to the plane of the outer faces of the side walls; the spacer section may be bent in this way to form it into a polygonal, especially a rectangular, spacer for use in the construction of a multiple glazing unit.

A double glazing unit may be constructed by securing together two panes of glazing material in parallel spaced relationship separated at or adjacent their marginal edges by a spacer made from a spacer element as described above.

Thus according to the present invention there is provided a sealed multiple glazing unit of wide air space comprising two panes of glazing material secured together in parallel spaced relationship and separated at or adjacent their marginal edges by a spacer extending around the periphery of the unit and made from a spacer element constituted by a hollow section of flexible, non-brittle material including first and second side walls and upper and lower walls extending between said side walls, the outer faces of said side walls being parallel and spaced apart at least 1 5 mm for locating first and second panes of glazing material in parallel spaced relationship, said hollow section including at least one reinforcing rib extending across the cavity in the hollow section.

The spacer element may be formed into a polygonal spacer, generally a rectangular spacer, by bending as described above; the free ends of the spacer element are preferably secured together where they meet. Alternatively, straight sections of the spacer element may be cut and joined at their ends to provide a desired polygonal spacer.

The panes of glazing material may, if desired, be adhered directly to the side walls of the spacer section using an adhesive. To prevent attack on the adhesive by atmospheric water vapour and ingress of water vapour into the air space when the unit is in use the joints between the spacer and the panes may be protected by applying a material having a low rate of transmission for water vapour over the joint.

In a preferred mode of construction, the spacer is inset from the marginal edges of the panes to define a channel between the outer peripheral face of the spacer and the inner faces of the panes and said channel is filled with a material having a low rate of transmission for water vapour. Preferably the material used has a rate of transmission for water vapour, measured in accordance with ASTM E-96, less than 5 gram/100 square inches/24 hours, 20mil film. Especially preferred materials have a rate of transmission, measured in accordance with ASTM E-96, less than I gram/100 square inches/24 hours, 20-mil film.

Examples of suitable materials which have a low rate of transmission for water vapour include homopolymers and copolymers derived from aliphatic hydrocarbon units, optionally substituted with halogen, especially polymers derived from monomer units containing 4 carbon atoms, for example, polyisobutylene.

To dry the air present in the air space of the unit, it is convenient to place a desiccant material in the cavity in the spacer section and to provide channels through the wall of the spacer element facing the air space of the unit. Thus, according to a preferred embodiment of the invention, there is provided a spacer element as described above including at least one channe extending through one of the upper and lower walls to provide communication between a cavity in the spacer section and the air space of a multiple glazing unit when the spacer element is assembled in said unit with said one wall facing the air space.

The spacer elements of the present invention are useful for the construction of multiple glazing units of wide air space, that is air spaces of 15 mm or more, for example air spaces of about 35 mm, the distance between the outer faces of the side walls of the spacer section corresponding substantially to the dimension of the air space of the unit. Spacer elements in accordance with the invention are especially useful for the construction of double glazing units having air spaces in the range 25 to 50 mm, especially 30 to 40 mm.

The spacer elements of the present invention will generally be used in the construction of double glazing units although they may also be used in the construction of other multiple glazing units. Thus for example, they may be used in the construction of triple glazing units having one wide air space (for example 35 mm) to provide good acoustic insulation and one relatively narrow air space (for example 6 mm) to provide good thermal insulation; in this case the spacer defining the narrow air space may, if desired, be of conventional construction.

The panes of glazing material used in the multiple glazing units of the present invention may be of plastics material but will generally be of glass. At least one of the panes defining each air. space should be capable of flexing to accommodate pressure differentials between the air space and the outside atmosphere. Thus, when the panes are of glass, at least one of these should be of toughened glass since toughened glass has a much greater capacity for flexing without breaking than untoughened glass. Preferably, double glazing units in accordance with the invention, especially units for use in glazing railway carriages, have both panes of toughened glass since this material is light and flexible and has good optical and safety properties.

The invention is illustrated but not limited by the following description with reference to the accompanying drawings in which:- Figure 1 is a perspective view of a spacer element in accordance with the present invention.

Figure 2 is a plan view of a spacer made by bending a spacer element as shown in Figure 1.

Figure 3 is a cross-section through a double glazing unit constructed using a spacer as shown in Figure 2.

Referring to Figure 1 a spacer element generally designated 1 comprises a hollow rectangular section of lead including side walls 2 and 3 and upper and lower walls 4 and 5 extending between the said side walls. The outer faces 6 and 7 of side walls 2 and 3 are parallel and, in a particular preferred embodiment the distance x between the outer faces is 35 mm. A continuous reinforcing rib 8 extends across the cavity of the hollow section between the upper and lower walls 4 and 5 and parallel to the outer faces 6 and 7 of the side walls 2 and 3, dividing the cavity into two parts. A series of holes 9 are provided in the upper wall 4 of the section.

These holes constitute channels extending through the wall 4 and provide communication between the cavities in the hollow section and the exterior.

Figure 2 shows a spacer element as shown in Figure 1 bent into the form of a rectangle about axes perpendicular to the outer faces 6 and 7 of the side walls. The presence of the reinforcing rib 8 assists in preventing collapse of the hollow section during the bending process. The spacer shown in Figure 2 is substantially rectangular in shape although, as can be seen from the drawings, the corners are rounded.

The free ends 11 and 12 of the spacer element shown in Figure 2 are soldered together to retain the spacer in the rectangular form.

Figure 3 shows a section through a double glazing unit for a railway carriage constructed using a spacer as shown in Figure 2. The parts of the spacer are designated by the same numerals as in Figure 1. To construct the unit, an adhesive 14, which may be an epoxy adhesive, for example, the epoxy adhesive available in commerce under the trade mark "Araldite", is applied to the faces 6 and 7 of the spacer and similar panes 15, 16 of toughened glass, each slightly larger in plan than the substantially rectangular spacer are brought into contact with the faces 6 and 7 respectively of the spacer so that the panes are positioned in spaced parallel relationship with the spacer adjacent their marginal edges. The panes may conveniently be held in place with spring clips (not shown) while the adhesive sets.

As shown in Figure 3, the spacer is inset from the marginal edges of the panes and defines a channel between the outer face of the spacer and the inner faces of the panes 15, 16.

The channel is filled with a mastic composition 17 having a low rate of transmission for water vapour, for example a polyisobutylene mastic composition or one of the commercially available materials known as "hot-melt" butyls. If desired, a protective adhesive aluminium tape 21 may be applied around the peripheral edges of the unit.

In the embodiment shown in Figure 3, the cavities in the hollow section of the spacer are filled with a particulate desiccant 19, for example a silica gel or molecular sieve dessicant.

It will be appreciated that, if this desiccant is to be present, it should be placed in the spacer element before the free ends 11, 12 of the spacer are soldered together. The gas in the air space 20 of the unit can communicate with the desiccant through the holes 9 in the wall 4 of the spacer.

WHAT WE CLAIM IS: 1. A spacer element for use in the construction of a sealed multiple glazing unit of wide air space said spacer element being constituted by a hollow section of flexible, nonbrittle material including first and second side walls and upper and lower walls extending between said side walls, the outer faces of said side walls being parallel and spaced apart at least 1 5 mm for locating first and second panes of glazing material in parallel spaced relationship, said hollow section including at least one reinforcing rib extending across the cavity in the hollow section.

2. A spacer element as claimed in claim 1 wherein said hollow section is a rectangular section, with at least one reinforcing rib extending across the cavity within the section.

3. A spacer element as claimed in claim 1 or claim 2 wherein a reinforcing rib extends substantially parallel to the outer faces of the side walls of the section between the upper and lower walls of the section.

4. A spacer element as claimed in any one of the preceding claims being of lead.

5. A spacer element as claimed in claim 1 including at least one opening in one of the upper and lower walls to provide communication between a cavity in the spacer section and the air space of a multiple glazing unit when the spacer element is assembled in said unit with said wall facing the air space.

6. A spacer element as claimed in any one of the preceding claims, the outer faces of the side walls being spaced apart at least 25 mm.

7. A spacer element as claimed in claim 6, the outer faces of the side walls being spaced apart 30 to 40 mm.

8. A spacer for use in the construction of a sealed multiple glazing unit comprising a spacer element according to any one of the preceding claims bent into a substantially rectangular form

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. glass has a much greater capacity for flexing without breaking than untoughened glass. Preferably, double glazing units in accordance with the invention, especially units for use in glazing railway carriages, have both panes of toughened glass since this material is light and flexible and has good optical and safety properties. The invention is illustrated but not limited by the following description with reference to the accompanying drawings in which:- Figure 1 is a perspective view of a spacer element in accordance with the present invention. Figure 2 is a plan view of a spacer made by bending a spacer element as shown in Figure 1. Figure 3 is a cross-section through a double glazing unit constructed using a spacer as shown in Figure 2. Referring to Figure 1 a spacer element generally designated 1 comprises a hollow rectangular section of lead including side walls 2 and 3 and upper and lower walls 4 and 5 extending between the said side walls. The outer faces 6 and 7 of side walls 2 and 3 are parallel and, in a particular preferred embodiment the distance x between the outer faces is 35 mm. A continuous reinforcing rib 8 extends across the cavity of the hollow section between the upper and lower walls 4 and 5 and parallel to the outer faces 6 and 7 of the side walls 2 and 3, dividing the cavity into two parts. A series of holes 9 are provided in the upper wall 4 of the section. These holes constitute channels extending through the wall 4 and provide communication between the cavities in the hollow section and the exterior. Figure 2 shows a spacer element as shown in Figure 1 bent into the form of a rectangle about axes perpendicular to the outer faces 6 and 7 of the side walls. The presence of the reinforcing rib 8 assists in preventing collapse of the hollow section during the bending process. The spacer shown in Figure 2 is substantially rectangular in shape although, as can be seen from the drawings, the corners are rounded. The free ends 11 and 12 of the spacer element shown in Figure 2 are soldered together to retain the spacer in the rectangular form. Figure 3 shows a section through a double glazing unit for a railway carriage constructed using a spacer as shown in Figure 2. The parts of the spacer are designated by the same numerals as in Figure 1. To construct the unit, an adhesive 14, which may be an epoxy adhesive, for example, the epoxy adhesive available in commerce under the trade mark "Araldite", is applied to the faces 6 and 7 of the spacer and similar panes 15, 16 of toughened glass, each slightly larger in plan than the substantially rectangular spacer are brought into contact with the faces 6 and 7 respectively of the spacer so that the panes are positioned in spaced parallel relationship with the spacer adjacent their marginal edges. The panes may conveniently be held in place with spring clips (not shown) while the adhesive sets. As shown in Figure 3, the spacer is inset from the marginal edges of the panes and defines a channel between the outer face of the spacer and the inner faces of the panes 15, 16. The channel is filled with a mastic composition 17 having a low rate of transmission for water vapour, for example a polyisobutylene mastic composition or one of the commercially available materials known as "hot-melt" butyls. If desired, a protective adhesive aluminium tape 21 may be applied around the peripheral edges of the unit. In the embodiment shown in Figure 3, the cavities in the hollow section of the spacer are filled with a particulate desiccant 19, for example a silica gel or molecular sieve dessicant. It will be appreciated that, if this desiccant is to be present, it should be placed in the spacer element before the free ends 11, 12 of the spacer are soldered together. The gas in the air space 20 of the unit can communicate with the desiccant through the holes 9 in the wall 4 of the spacer. WHAT WE CLAIM IS:

1. A spacer element for use in the construction of a sealed multiple glazing unit of wide air space said spacer element being constituted by a hollow section of flexible, nonbrittle material including first and second side walls and upper and lower walls extending between said side walls, the outer faces of said side walls being parallel and spaced apart at least 1 5 mm for locating first and second panes of glazing material in parallel spaced relationship, said hollow section including at least one reinforcing rib extending across the cavity in the hollow section.

9. A sealed multiple glazing unit of wide air space comprising two panes of glazing material secured together in parallel spaced relationship and separated at or adjacent their marginal edges by a spacer extending around the periphery and made from a spacer element as claimed in any of claims 1 to 7.

10. A multiple glazing unit as claimed in claim 9 wherein the spacer element is secured to said panes by an adhesive.

11. A multiple glazing unit as claimed in claim 10 wherein the adhesive is an epoxy adhesive.

12. A multiple glazing unit as claimed in any of claims 9 to 11 wherein the spacer is inset from the marginal edges of the panes to define a channel between the outer peripheral face of the spacer and the inner faces of the panes and said channel is filled with a material having a low rate of transmission for water vapour.

13. A multiple glazing unit as claimed in claim 12 wherein said material is a homopolymer or copolymer derived from monomer units containing four carbon atoms.

14. A multiple glazing unit as claimed in any one of claims 9 to 13 wherein the spacer is made at least in part from a spacer element as claimed in claim 5, the openings in the spacer element facing the air space to provide communication between the air space and a cavity in the spacer element which cavity contains a dessicant.

15. A double glazing unit as claimed in any of claims 9 to 14 wherein one or each pane is a toughened glass pane.

16. A spacer element for a multiple glazing unit substantially as hereinbefore described with reference to, and as illustrated in, Figure 1 or Figures 1 and 2 of the accompanying drawings.

17. A double glazing unit substantially as hereinbefore described with reference to, and as illustrated in, Figure 3 of the accompanying drawings.