Stock material or miscellaneous articles – Sheet including cover or casing – Including elements cooperating to form cells
Reexamination Certificate
2002-07-17
2004-03-02
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Sheet including cover or casing
Including elements cooperating to form cells
C428S116000, C428S034100, C156S109000, C156S290000, C052S783100, C052S786100, C052S786130, C052S793100, C052S793110, C052S794100
Reexamination Certificate
active
06699558
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to glazing systems such as windows, skylights, atriums, greenhouses, sunrooms and the like.
BACKGROUND OF THE INVENTION
Honeycomb transparent insulation was first developed in the early 1960's in order to enhance the insulation value of glazed systems, with minimum loss of light transmittance. Honeycomb transparent insulation consists of transparent-walled honeycombs, with open-ended cells whose axes are oriented parallel to the normal vector of the plane of the glazing. The materials transmit light by a forward-reflection process, and impede heat transfer by suppressing convection and radiant transfer. These mechanisms are well understood and described in the technical literature. See, for example, “Coupled Radiative and conductive heat transfer across honeycomb panels and through single cells”, K. G. T. Hollands et al., Int. J. Heat Mass Transfer v.27, n.11 pp. 2119-2131, 1984; “An approximate equation for predicting the solar transmittance of transparent honeycombs”, K. G. T. Hollands, K. N. Marshall, and R. K. Wedel, Solar Energy, v.21 pp. 231-236, 1978).
Honeycomb transparent insulation is typically made from transparent plastics such as acrylic, polycarbonate, or polypropylene. These are manufactured by a number of different techniques, including capillary bundling, extrusion, and film-fabrication. Their properties (such as light transmittance, insulation value, rigidity, weight, etc.) strongly depend on how they were manufactured. Examples of honeycomb transparent insulations are lnsolCore®, a film-based transparent insulation made by Advanced Glazings Ltd., Nova Scotia, Canada, Kapillux®, a capillary-bundled transparent insulation made by Okalux Kapillarglas Gmbh. of Marktheidenfeld-Altfeld, Germany, and AREL®, an extruded transparent insulation made by Arel Energy Ltd., Yavne, Israel.
It is often desirable to use honeycomb transparent insulation in a glazing unit, where it is mounted between two panes of glass, sheets of plastic, or similar, taking the place of the air gap or gas layer that traditionally provides insulation. Such glazing units can be used to let daylight into buildings, while at the same time, providing good insulation. They can be used in skylights, sunrooms, atriums, or certain window applications, or anywhere natural light is desired but a clear view of the outdoors is not necessary or desirable. The use of such honeycomb transparent insulation-filled glazing units gives the advantage of lower heat transfer (which in cold climate, causes warmer interior surface temperature, in increased thermal comfort and less condensation, and in warm climates, means lower air conditioning costs), diffuse light transmittance (resulting in high-quality uniform natural light and lower glare), and privacy.).
Rigid thick-walled honeycombs are straightforward to use in glazing units, where they are simply sandwiched in between the two sheets of glass. The rigidity of such transparent insulations prevents them from ‘sagging’ under their own weight, when used in inclined or vertical positions. Thus it is not necessary to fix the transparent insulation to the frame of the glazing unit or to on or both of the glazings. An example of the use of a glazing unit incorporating a rigid honeycomb transparent insulation is Okalux, made by Okalux Kappilarglas Gmbh. of Marktheidenfeld-Alffeld, Germany. This product consists of rigid capillary-bundled honeycomb transparent insulation, covered on both sides by a light diffusing fiberglass veil cloth, and sandwiched inside two pieces of clear glass, and surrounded by a spacer/frame to create a glazing unit. It is important to note that the fiberglass cloth is not bonded to the honeycomb, and is included for the purpose of diffusing light as well as for aesthetic value.
One very important parameter in determining properties of honeycomb transparent insulations is wall thickness. It is often desirable to construct honeycomb transparent insulations with the minimum practical wall thickness, because (with all other variables held constant) this results in minimum solid heat conduction, minimum optical losses, and material cost. However, the rigidity of the honeycomb is reduced as the walls become thinner. The range of practical wall thicknesses is determined to some degree by manufacturing method. The film fabrication method is known to be useful for making honeycomb transparent insulations with very thin walls. Film-fabricated honeycombs are inherently flexible, and this flexibility increases as wall thickness decreases. For example, InsolCore, a film-fabricated transparent insulation made by Advanced Glazings Ltd. of Nova Scotia, Canada, has wall thickness on the order of 0.001″. This flexibility can be used advantageously: such materials can be compressed to reduce volume while shipping and later re-expanded; and such materials can comply to the contours of underlying ceiling layers in ceiling-attic construction as described in our co-pending application no. CA 2,254,457.
However, flexibility becomes problematic when using honeycomb transparent insulation in applications such as daylighting, where the transparent insulation is mounted in a glazing unit between two sheets of rigid glazing material (typically glass, or plastic such as polycarbonate or acrylic). If a flexible honeycomb is simply sandwiched between glazings, as is done with rigid honeycomb transparent insulations, it is likely to sag under its own weight, drawing away from the frame at one or more edge of the glazing unit. This may be caused by gravity if the glazing unit is handled or mounted in a non-horizontal position, or it may simply happen as a result of dimensional changes caused by residual internal stresses in the honeycomb transparent insulation itself. One solution has been to attach the honeycomb to the edge (frame) of the glazing cavity, or to one or both of the rigid glazings that define the glazing unit itself. However, such a mounting procedure is labour-intensive and the use of adhesive to fasten a honeycomb to a glazing results is typically aesthetically displeasing.
It is well known that honeycomb transparent insulation scatters light and cannot transmit images at off-normal incidence. Therefore, glazing units filled with transparent insulation cannot be used in window applications where preservation of view is important. But the advantages of diffuse glazings for daylighting applications are well-known. Specifically, diffusely-transmitted light distributes throughout the interior of a building, reducing glare and shadowing relative to specularly-transmitted daylight. Filling the interior of a glazing unit with honeycomb transparent insulation contributes to the diffusing power of this glazing system. However, honeycombs are ‘conical scatterers’, that scatter incoming light over a range of azimuth angles, while preserving the original angle of inclination. This means that honeycomb transparent insulations have a limited ability to provide light diffusion at near-normal incidence angle. This also means that they transmit images at normal incidence, and thus a glazing unit made with specular (non-diffusing) glazings and honeycomb transparent insulation provides incomplete privacy. This is improved by the addition of one or more secondary diffusing layers, such as a loose-weave fibreglass cloth or veil, as is known in the state of the art.
The rigidity of a honeycomb material is greatly increased by bonding a sheet of material to one or both sides of the honeycomb. This principle is well-known in engineering and material science, and numerous light-weight composite honeycomb-core structural materials exist today. Examples are door panels made from wood veneer bonded to paper honeycombs, and high-tech plastic and metal honeycomb-core materials used in the aircraft industry. As well, honeycomb cores, adhesives, and skinning materials are readily available throughout the supply chain of the composites industry. The present invention takes advantage of the aforementioned principle in order to create a r
(Marks & Clerk)
Advanced Glazings Ltd.
Boss Wendy
Jones Deborah
LandOfFree
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