CA1061188A - Add-on multiple glazing - Google Patents

Abstract

ABSTRACT
The invention relates to an architectural glazing unit for converting installed glazing to multiple glazing, comprising no more than one transparent pane, an elongated spacer element adjoining marginal portions of a first major surface of the pane around the perimeter of the pane, each longitudinal portion of the spacer element having a first surface and a second surface on opposite sides thereof, wherein the first surface faces said marginal portions of the pane in adjoining relationship thereto, and the second surface faces outwardly, away from the marginal portions of the pane. A
ribbon of essentially moisture vapor impervious material extends around the perimeter of the unit adhered to the second surface of the spacer element and overlying peripheral edge surface portions of the pane. Moisture-resistant sealant is interposed between the ribbon and edge surface portions of the pane so as to provide adhesion and a hermetic seal therebetween. The unit provides for easier installation and a more effective and longer lasting multiple glazed product.

Description

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This is a division of application Serial No. 221,741 filed on March 10, 1975.
Thls invent~on relates to the conversion of installed single glazed windows into multiple glazed windows, more particularly to an improved structure and method for affixing an additional pane of glass and a spacer element to an existing window installation so as to create a double glazed unit having a hermetically sealed, insulatlng airspace between the panes.
~ lthough it has long been recognized that double glazed windows possess much greater insulating ability than single glazed windows, most installations have been provided with single glazing for the sake of economizing on construction costs. But with the rapid rise o the costs of heating and cooling buildings, -this economy has proven to be false. Thus, it has become increasingly desirable to convert single glazing to double glazing, not only for improving the insulating properties, but also for the sake of the advantages attained from the addition of a tinted or reflectively coated pane. Unfortunately, remov-ing and discarding existing wlndows and installing whole double gla7ed units in their place incurs prohibitive costs for labor and materials.
Accordingly, it is an ob~ect of this invention to provide a method and means for quickly and easily converting a single glazed window into a double glazed window by sealing an additional pane of glass to the existing installation. The present invention is specifi-cally adapted to provide easy installation, ready adaptability to any size of window opening or frame construction, superior moisture barrier integrity, and improved structural strength.
Various attempts have been made in the prior art to provide on-site installation of secondary panes of glass, but all suffer from certain shortcomings that have discouraged their use. A typical prior art approach can be seen in United States Patent No. 2,436,037 (Doney) where a rubber gasket serves as both spacer and sealing means.

The rubber-to-glass seal utilized therein is a relatively poor moisture - 1 - ~

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bar~ier, since most natural and synthetic ~ubbers are somewhat pervious, thus rendering the sur~aces of the airspace susceptible to condensation.
Rubber is also susceptible to degradation upon exposure to sunlight and weather conditions. Such an arrangement is limited to installation from the outside on relatively deep ~rames, a distinct disadvantage at many locations, especially on large buildings. ~urthermore, sealing difficulties would be encountered at the mitered corner joints called for in Doney. Another prior art approach is shown in United States Patent No. 3,299,591 (Woelk) where a strip of epoxy resin serves as both spacer and sealant. That arrangement provides only a short barrier against moisture penetration, and the epoxy resin, which is apparently required for the sake of high adhesion strength and room temperature curability, is not a reliable sealing rnaterial because of its moisture vapor transmissibility and low ~emperature inflexibility. In order to obtain an attractive appearance, lt also appears that specialized extruding or casting equipment for the epoxy would have to be employed at the installation site. A furt~er prior art approach is disclosed in United States Patent No. 3,573,149 (Tibble et al). In that patent, a neoprene composition is melted and cured in situ to effect a seal.
Again, the barrier in the path of moisture penetration is short in length, and the curable thermoplastic material required is not noted for its moisture barrier properties. Installation requires the use of specialized electrical equipment at the site and lengthy heating times.
The technique is also susceptible to uneven heatlng which may, in turn, yield uneven sealing.
~dd-on glazing devices of a different type can also be seen in the following four United States Patents relating to automobile windows:
1,777,435 ......... Hogelund 1,915,098 ......... Kile 1,945,742 .. ~...... Hilger

2,098,127 ......... Auger ~06~38 Each of these re~e~ences suffers f~om lack of permanency and integrity of seal, which are required ~or acceptance in the architectural glazing field. Each employs an unprotected organic spacer whlch is sub~ect to moisture penetration.
In accordance with the present lnvention, there is pro-vided an architectural glazing unit for converting installed glazing to multiple glazing which comprises no more than one transparent pane and an elongated spacer element ad~oinlng marginal portions of a first major surface of said pane around the perimeter thereof. Each longitudinal portion of the spacer element has a first surface and a second surface on opposite sides thereof, the first surEace facing and adjoining said marginal portions of the pane and said second surface faclng outwardly away from said marginal portions. ~ ribbon of essentially moisture vapor impervious material extends around the perimeter of the unit and is adhered to the second surface of the spacer element and overlying peripheral edge surface portions of the pane. Moisture~resistant sealant is interposed between the ribbon and edge surface portions o~ the pane to provide adhesion and a hermetic seal ~herebetween.
The inventlon also provides a method of increasing the insulatlng value of a vision opening in a building wall structure which utillzes a glazing unit as defined above although, for the practice of this novel method, the ribbon may be dispensed with, if desired. Thus, the method of the invention comprises the following steps:
providing at an installation site a subassembly which includes an additional transparent pane and a spacer element affixed to marginal portions of one ma~or surface of said additional pane, having a hermetically sealed barrier against moisture penetration through said spacer element and between said spacer and said pane;
~llgning said subassembly in a generally parallel rela-tionshlp to a ma~or surface of Lhe installed pane, with said spacer ~6~8~

element disposed between said paneS, ~nd W~th a band of an ~t least partially uncured sealant disposed between said spacer element and said installed pane, said sealant being comprised of a polymeric composition having a moisture vapor transmittance of less than about 15 grams of water per 24 hours per square meter ~or 1 mil thlckness and being co-herent and tacky but flowable under pressure at room temperature; and biasing said subassembly onto said ma~or surface o~ the installed pane and applying a compressive force on said sealant band therebetween until the sealant ~lows and forms a resilient structural bond and a hermetic seal between said spacer element and said major surface of said installed pane.
The invention will now be descrlbed further by way of example only and with reference to the accompanying drawings, wherein:
Figure 1 is a perspective interior view, partially cut away, of a typical single glazed window installation upon which the present invention may be practiced;
Tigure 2 is a cross-sectional view of an edge strip assembly having an organic spacer and sealant material applied to a moisture resistant ribbon in accordance with an embodiment of the present invention;
Figure 3 is a cross-sectional view of an alternate embodiment of the edge strip assembly;
Figure 4 is a fragmentary cross-sectional view of the edge strip shown in Figure 2 applied to the periphery of a pane of glass to form a subassembly;
Figure 5 is a fragmentary cross-sectional view of the subassembly shown in Figure 4 with sealant material applied thereto;
Figure 6 is a cross-sectional view of the subassembly showm in Figure 5 in a packaged form for handling and shipping;
Figure 7 is a cross-sectional view of the subassembly sho~m in Figure 5 in an al.ternnLe packaged form ~L13 6~

~ igure 8 is a perspective inte~ior view, partially broken away, of the windo~ structure shown in '~igure l after conversion to double g~azing in accordance with one embodlment of the present invention;
Figure 9 is a ~ragmentary cross-sec-tional view, taken along lines 9-9 in Figure 8 of a completed installatlon of the subassembly shown ln Figure 4 onto a previously single glazed window;
Figure 10 is a fragmentary elevation of a subassembly mounted onto an existing glazing installation showing one means for vacuuming the airspace;
Figure 11 is a fragmentary elevation of a subassembly having a vacuuming tube placed in a ~oint;
Figure 12 is a schematic, fragmentary, cross-sectional view of an alternate framing treatment for a narrow window frame in conjunction with the present invention;
Figure 13 is a schematic, fragmentary, cross-sectional view of an alternate framing treatment for a wide window frame in con-junction with the present invention;
Figure 14 is a schematic, fragmentary, cross-sectional view of an alternate framing treatment using a nail-less, screw-less trim insert in con~unction with the present in~ention;
Figure 15 is a fragmentary cross-sectional view of a related subassembly construction utilizing a rigid spacer;
Figure 16 is a fragmentary cross-sectional view of a completed installation of the subassembly shown in Figure 15 onto a previously single glazed window;
Figure 17 is an exploded, fragmentary, cross-sectional view of a further related construction showing the relationship of the parts prior to assembly;
Figure 18 is a fragmentary, cross-sectional view of a completed installation of the embodiment of Figure 17;

10 E;~188 Flgure 19 is a fragmentary cross-sectional view of another subassembly construction whlch has a-moisture barrier of sealants only;
Flgures 20, 21 and 22 are fragmentary cross~sectional views of variations of the subassembly embodlment shown in ~igure 19;
~ igure 23 is a fragmentary cross-sectional view of a simplified subassembly construction employing a metal spacer; and Figure 24 is a fragmentary cross-sectional view of yet another subassembly construction which provides an organic spacer with a moisture resistant wrapper.
The drawing figures which specifically relate to this particular invention are Figures 1 through 14, 16 and 18. However, the remaining drawing figures are of assistance in understanding the concept of the invention and various related constructions.
Depicted in Figure l is an interior view of a single glazed window unit that would t~pically form part of a building wall structure, the window comprislng a pane of glass 15 and a frame 16. The conversion of such a window to double glazing will serve as an illu-strative example of thls invention.
In Flgure 2, there can be seen a cross-sectional view of a preferred embodiment of an edge strip arrangement which forms the basis for the present invention. The edge strip includes as a base element a continuous ribbon of moisture resistant (essentially moisture impermeable) material 20, preferably an aluminum foil or strip having a thickness of about 8 mils. Although somewhat more susceptible to moisture penetration, various films of plastic, such as the dense poly-ethylenes, may be used for the ribbon 20. A continuous length of organic spacer element 21 is affixed along the length of the ribbon by means of an adhesive layer 22. Adhesive 22 may be a sealant material, but ls selected with strong adhesion as the primary desideratum so as to prevent ~6~

dislocation of the flexible ~F~anic spacer in the co~pleted installation.
The adhesive 22 should be rigid in the temperature range encountered in window lnstallations, and for ease of manufacturing, it should be capable of forming an instant bond between the foil and the spacer. ~n adhesive that has been found suitable is USM 13Ll, a polyethylene copolymer sold by United States Machinery Corporation, which is applied in a hot melt form to the foil which is also heated. Such an adhesive forms an exceptionally strong bond after the adhesive has cooled and set, the 180 degree peel strength between the spacer and the ribbon exceeding 25 pounds per lineal inch as determined by ~. S. T. M. D-903~49T.
The expressions "moisture resistant", "barrier against moisture penetration"~ and "hermetic seal"~ as used herein, reEer to an ability to prevent passage of water vapor to such an extent that the sub~ect material or structure is capable of being utilized in a multiple glazed architectural installation. To qua]ify for such archltectural use, a material or structure should present enough of an obstacle to water vapor transmission to preclude condensation of water vapor in the interior of a multiple gla~ed unit at temperatures down to about 0 F.
(i.e., about 1.77 x 10 grams of water per cubic inch of air ln the unit) and preferably lower, over a period of several years. The time period required is at least about three to about five years, but pre-ferably is at least about ten years, and in optimum cases is at least about twenty years. The amount of water vapor penetration depends not only on the inherent moisture vapor transmission of the material employed as the obstacle, but also on the dimensions (e.g., thickness) of the obstacle ln the path of water vapor penetration. ~ecause visual aesthetics must be considered in regard to architectural glazing 9 it is desirable to mlnlmize the dimensions of the water vapor barriers, thus materials having a relatively low moisture vapor transmission are preferred.
For thls reason, lt ls generally preferred that the materials used for .

~6~38 molsture barriers in multiple ~lazing ha~e a moisture vapor transmission of less than about 15 grams (preferably less than about 6 grams) per 24 hours per square meter per mil thickness at 100~. and 90% relative humidi~y as determined by A. S. T. ~. E-96-66~. Desiccants are often included in multiple glazed units to adsorb moisture vapor in the air-space, and when a desiccant is employed, the requirements for moisture barriers may be relaxed by an amount corresponding to the water adsorbing capacity of the desiccant.
Referring agaLn to ~Lgure 2, spacer 21 may be any solid or semisolid rubber or synthetic polymeric material which maintains sufficient rigidity under ambient temperature conditions to retain two panes of glass in substantially parallel, spaced relationship. A pre-ferred spacer is the spacer-dehydrator disclosed in United States Patent No. 3,758,996, which may be described generally as a moisture vapor transmittable matrix of a block copolymer of styrene and butadiene having interspersed therein a desiccating material. If such a spacer-dehydrator is not used, separate desiccating material is preferably affixed to or embedded in at least a portion of the spacer along its length or placed in the airspace at the time of installation - at the site.

As shown in ~igure 2, a continuous band of mastic 23 is applied to ribbon 20 parallel to spacer 21. The composition and width of mastic 23 are selected so as to form a moisture resistant barrier when bonded to the glass surface, as will be set forth with more parti-cularity hereinbelow. Mastic 23 is desirably a room temperature curable or vulcanizable material that will cold flow to form a moisture resistant seal and a resilient structural bond. Butyl-based mastics are preferred, such as the two component, room temperature curable, butyl-based mastic disclosed in United States Patent No. 3,791,910 to George H. Bowser.
On-site assembly is substantially expedited by ~roviding a tacky, non-curing composition for mastic 23. A preferred non-curing mastic has the follow:Lng composition:

61~L88 (Component) (Weight %) polyisobutylene (viscos-ity average molecular weight 75,000 - 100,000) 15-50 polyisobutylene (viscosity average molecular weight 8,000 - 10,000) 10-45 carbon black 10-45 silica pigment 5-15 zirconium orthosilicate 5-15 polybutene 20-50 zinc oxide 0-5 gamma-glycidoxy-propyltrimethoxysilane 0-5 On an extending portion of ribbon 20, on the opposite side of spacer 21 from mastic 23, there is provided a band of adhesive 24. The primary function of adh~sive 24 is to hold the extending portion of ribbon 20 against the side of spacer 21 when the ribbon is folded in accordance with assembly procedures to be set forth below. Thus, adhesive 24 may be merely a narrow bead or discontinuous spots of adhesive material. In most cases, however, band 24 may be the same compound as mastic 23. As an alternatè embodiment for the edge strip, there may be a single mastic-adhesive layer 25 applied to substantially the entire surface of one side of ribbon 20 as shown in Figure 3. Although the Figure 3 embodiment lacks the advantages of using the hot-melt adhesive 22 of the Figure 2 embodiment, it possesses sealing advantage in that the organic spacer 21 may be protected by a continuous layer of moisture resistant mastic. Mastic 25 may consist of the compositions disclosed in United States Patent No. 3,791,910 or the non-curing mastic described above.
Turning now to Figure 4, there is shown the edge strip of Figure 2 applied to a rigid transparent pane 30, which is the additional pane to be added to the exlsting installation. Pane 30 may be glass or plastic, and may be tinted or reflectively coated in accordance with 6~

known ~eth~ds in the art. ~hen the pane 30 ~S coated, especially when the coatings are sub~ect to deterioration, the coating should be on inner sur~ace 31, which will ultimately be exposed to only a sealed air-space. Care must be taken to clean all oil, dirt, and other contaminants from~the pane using appropriate solvents. Glass panes may also have their edges lightly seamed to reduce lacerative risk to personnel and to prevent tearing of ribbon 20.
As shown in Figure 4, the spacer 21 is placed with one side in close contact with surface 31 of the pane. Sealant or adhesive may optionally be included between the spacer and the pane for extra sealing or extra strength but is usually not needed. The extending portion of ribbon 20, which carries mastic 23, is folded around the edge of pane 30 and is pressed against the pane so as to flow the mastic and create a seal between the ribbon and the peripheral edge 32 of the pane as well as to the margln of major surface 33. The other extending portion of the ribbon, carrying adhesive or mastic 24, is folded against and adhered to the side of spacer 21 which is adjacent to the side already adhered to the ribbon. Generally, the attachment of the edge strip assembly is started at one corner of the pane and is continued about the entire periphery of the pane with a single length of the edge strip.
At corners, the spacer may be notched to produce mitered joints. Where the ends meet, the edge strip may be trimmed to butt the ends together and sealant added to the joint, or the spacer may be cut from an over-lapping length of the edge strip and the extra length of ribbon 20 sealed across and beyond the joint.
Several important advantages for the presence of ribbon 20 can be seen at this point. First, a flexible organic spacer is given structural rigidity by reason of its attachment to the ribbon. Also, a spacer, flexible or rigid, is thereby provided with a stronger structural attachment to pane 30. Anothe~: important advantage is that the presence of ribbon 20 permi~s the use of a greater ~idth of moisture resistant material (sealant 23) for sealing the inter~ace between the spacer and pane 30, and because the moisture resistant material is deplo~ed between the ribbon and surfaces of pane 30 rather than between the spacer and the pane, it enables one to exert greater and more uniform pressure on the material to form a good seal than could be done by attempting to press a flexible organlc spacer itself onto the pane. Furthermore, the ribbon provides a laterally and longitudinally continuous, moisture resistant barrier ~n the path of moisture penetration into a pervious organic spacer.
Optionally, a band of mastic 34 may be applied along the exposed surface of the portion of ribbon 20 which extends around the spacer and is parallel to the major surfaces of pane 30 as shown in Figure 5. Mastic 34 should be tacky and non-curing, preferably the butyl-based composition described above in connection with mastic 23, and may be conveniently supplied in strips on release paper. The release paper may be pressed in place to flow the mastic and to effect a seal and then peeled from the mastic. ~astic layer 34 should cover substantially all of the surface of the aforesaid portion of the ribbon. The addition of mastic 34 may be omitted without seriously affecting performance of the unit, but its presence has been found to result in the formation of a superior seal with a minimum amount of applied pressure.
The subassembly shown in Figure 5 is ready for mounting onto the existing glazing. The preceding fabrication of the subassembly may take place at a central location and the subassemblies shipped to the job site, or the fabrication may be performed at the site. When the subassemblies are shipped in prefabricated form it is desirable to protect mastic 34 such as by retaining release paper 35 thereon as shown in Figure 6, or by providing a strippable overlay of sheet material 36 (Figure 7) over the entire open face of the subassembly. Overlay 36 not only protects ~astic 34 but ~lso m~intains the cleanliness of the inner surface 31 of pane 30 and, if the overla~ is a relatively impervious material, preserves the desiccant that may be carried by the spacer and protects the ilmer surface from moisture.
In Figure 8, the subassembly of Figure 5 is shown installed onto the interior of the existing single glazed window depicted in Figure 1. Interior installation is advantageous for the sake of easy accessibility, but the present invention can also be used for adding glazing on the exterior side. Exterior installation may even be pre-ferred in some cases because of particular sash configurations or for better reflectivity when reflectively coated glass is being added.
Optional decorative trim 40 is also shown in Figure 8 applied around the periphery of the wlndow. Details of the installation may be seen in Figure 9, which is a cross-sectional view of the edge portion of the window, taken along lines 9-9 in ~igure 8.
When installing the subassembly to surface 41 of existing pane 15, that surface and ~he adjacent areas of frame 16 must be thoroughly cleaned. ~ layer o~ moisture resistant mastic 42 is then applied around the periphe~y of pane 15 along a path corresp~nding generally to the outline of spacer 21 on the subassembly as shown in Figure 9. The width of the layer 42 may be wide enough to extend at least slightly above and below the outline of the area that spacer 21 will contact on surface 41 so as to provide a maximum area of contact and some margin for error. Extending mastic 42 all the way to frame 16 will provide an even greater margin for error and expedite alignment of mastic 42 on surface 41. Mastic 42 is taclcy, preferably the non-curing, butyl-based sealant described above in reference to mastic 23, and may be carried on release paper which is pressed against the pane 15 and then peeled off. The combined thicknesses of mastic 34 and mastic 42 should be sufficient to assure a flowiilg of the mastic material when they are ~6~ 8~

pressed together, thus eliminat~ng Yoids and effectin~ a cont~nuous hermetic seal. ~t has been found satisfactory to provide mastics 34 and 42 each with thickness of about one-sixteenth of an inch, or, when mastic 34 is not employed, ta provide mastlc 42 alone with a thickness of about one-eighth of a~ lnch.
The subassembly is next moved into position and aligned with mastic 42. Setting blocks of a resilient material such as neoprene are inserted at spaced lntervals across the bottom edge of the subassembly in the space between the subassembly and frame 16 in accordance with lo conventional glazing techniques. The subassembly is then pressed against pane 15 to effect a seal with mastic 42. Pressure may be applied by clamp means carried by the glass holding equipment, or by special leverage means coacting with the frame or wall structure. ~nother technique is to impose a vacuum in the newly-created air space 43 for a sufficient time to permit the mastic to flow and seal. Both vacuum and mechanical means may be used simultaneously to obtain the best results.
The vacuum may be attained by inserting a hollow needle 47 through ribbon 20 and spacer 21 as shown in ~igure 10 if space permits, and afterwards sealing the puncture. In most cases, however, it is preferable to seal a length of flexible, small-gauge plastic tubing 48 into the ~oint of the edge strip during fabrication of the subassembly as shown in Figure 11 so as to communicate the air space with the exterior.
After the vacuum has been drawn by way of the tubing and held for a period of time, the vacuum is released and the tubing sealed or the tube removed and the aperture sealed. In some cases, it is desirable to include a breather tube in double glazed units as disclosed in United States Patent No. 3~771,276. In such cases, the breather tube may be used to pull the vacuum in the airspace, At this point in the assembling procedure, the resulting double glazed unit is essentially complete. As an extra precaution, lt may be desirable to ext~ude a scalant 44 into the gap le~t around the perimeter of the unit. Res~lient butyl~, polysulfide-, or silicone-based sealants may be used ~or this purpose. Such a sealant may also be appropriately filled or colored so as to serve as a decorative trim.
~or the sake of appearance, it may also be desired to fasten metal, plastic, or wooden trim 40 to frame 16. Although the ribbon 20 and the various mastic layers provide adequate strength in themselves for holding the resulting double glazed unit together, the trim 40 may also be adapted to provide a secondary restraining force.
The add-on multiple glazing technique of the present invention can be adapted for use with virtually any window frame con-figuration. Two such adaptations are shown in FiguTes 12 and 13.
Figure 12 depicts schematically a completed installation on a relatively narrow frame 16a utilizing a modified trim member 40a. Figure 13 is a schematic representation of a completed installation involving a rela-tively wide frame 16b and modified trim 40b. In cases where extremely narrow frames are encountered~ it may be necessary to fasten additional strips of material to the frames to extend the width of the frames.
Another modification, showm in Figure 14 in connection with a schematic illustration of a completed installation, is the use of a nail-less, screw-less trim member 40c. Such a trim member ls provided with an extending flange 45 which carries a plurality of barbs 46. The trim is installed by merely pressing the flange 45 into the sealant 44, where the outwardly oriented barbs will engage the sealant and resist removal.
Heretofore the description of the invention has related to the use of organic spacers,but the invention can be adapted to employ metal spacers. In Figure 15, there is sho~m a subassembly embodiment which includes a rigid spacer 50, preferably made of metal, containing desiccant 51, and provided with an opening 52. De~ails of a preferred metal sRacer are disclosed in United St~tes ~tent No. 2,684,266. Since metal spacers generally require welding at the corner ~oints, the unit sho~m in ~igure 15 is contemplated as being primarily a factory fabri-cated item. As such, the mastic materials employed may be selected from an~ of the moisture resistant sealant compounds previously discussed, preferably the butylbased sealants. Since the metal spacer forms a rigid structure, the mastics may be chosen primarily for their sealing charac-teristics rather than thelr structural strength properties. Spacer 50 may be sealed to the additional pane 15 by means of sealant 53 so as to form a primary hermetic seal. ~ moisture resistant ribbon 54, (preferably metallic) coated with a sealant 55, is sealed to the outer surface of the spacer and folded around the edge of the pane 30 so as to form a moisture resistant seal with its peripheral edge surface 32 and with the margin of ma~or surface 33. The secondary seal thus for~ed and the primary seal at 53 together provide a superior moisture barrier. ~n adequate seal can be achieved with sealant 55 alone, thus sealant 53 could be eliminated if desired. Since a metal spacer such as spacer 50 is essen tially moisture lmpervious, ribbon 54 need not be extended over the adjacent surface of the spacer as done in the organic spacer embodiments.
The ribbon does serve another function, however, that being reinforce-ment of the attachment of the spacer to the pane 30. For this reason, it may be advantageous to likewise provide a ribbon of suficient width to enable a portion to be folded around a corner of the spacer and to be adhered to the adjacent front surface of the spacer in the case of metal spacers as well.
~ completed installation of the subassembly of Figure 15 onto a single glazed window may be seen in Figure 16. Mounting techniques are similar to those described above in connection with the organic spacer embodiments. Mastic layer 56 is preferably thP same tacky, non~curing butyl-based material previously described, and is applied to the glass 15 1~6~88 in the same manner ~s mastic 42 in the previ~us embodiments. Prior to mounting, additional mast~c may be applled to the exposed surface of spacer 50 which is parallel to the ma~or surfaces of pane 30 in order to provide a mastic-to-mastic bond with layer 56.
The techniques of the present invention may also be applied to a method of attaching a metal spacer to an additional pane which may be carrier out at the Job site without the need for welding.
Referring now to Figure 17, there is shown an unwelded segment of a metal spacer 60 having desiccant 61 and an opening 62. A separate segment is provided for each side of the unit, and each segment is individually affixed to additLonal pane 30 by means of adhesive or sealant layer 63 which is preferably tacky so as to form an instant bond. ~ continuous ribbon 64 of moisture resistant material (essentially moisture imper-meable), preferably aluminum ~oil, having a layer of tacky, non-curing, moisture resistant sealant 65 thereon~ is then applied to the edge of the unit, folded around the edge of pane 30 and a corner of spacer 60 and pressed to flow the sealant and form a seal. Because the ribbon is passed continuously around the corners o~ the unit, a good seal can be attained without requiring the ~oints of the metal spacer to be welded.
The ends of the ribbon 64 should be overlapped to effect a seal.
The subassembly of Figure 17 is installed onto the exist-ing gla~ing 15 as shown in Figure 18 with the same mounting procedures as set forth above, the critical seal being effected by a tacky, non~
curing mastic 66 that is similar to or the same as mastic 56.
Although the preceding embodiments are preferred because of the combined structural and sealing advantages of the peripheral ribbons employed on the subassemblies, subassemblLes suLtable for archi-tectural use can be produced without such a ribbon. Examples of such embodimen~s may ~e seen in Figures 19 through 24.

The subassembly shown ln ~Figure 19 is essentially the same as the embodiment Df ~lgure 4, except that the ribbon has been omitted, and ln lieu thereof moisture resistance is provided by sealant layer 70 and structural strength is provided by adhesive layer 71.
barrier for resisting moisture penetration through organic spacer 21 or between the spacer and pane 30 is provided by selecting appropriate materials and thicknesses for sealant 70. The preferred material for sealant 70, as well as for the sealants in Figures 20 through 22, is the previously described tacky, non-curing, butyl~based composition.
When such a tacky sealant is employed, it would be desirable to protect the exposed surfaces o~ the sealants shown in Figures 19 through 22 during shipping and storage with suitable strips of release paper.
~dhesive 71 may be a moisture resistant material as well, or, as shown in Figure 20, a contlnuous layer of moisture resistant sealant 72 may extend around three s~des o~ the spacer, thereby serving as both moisture barrier and structural ~oining means.
Figure 21 depicts a two-layered approach where an extra thick body of sealant 73 serves as a moisture barrier. This approach requires moisture to penetrate an exceptionally great thickness of moisture resistant sealant in the direction parallel to the major surfaces of pane 30 before 1t can enter organic spacer 21. The body of sealant 73 protrudes beyond the spacer so as to engage and form a seal with an installed pane to which the subassembly is to be mounted.
greater area for sealing a subassembly to an installed pane may be prov~ded by employing an extended body of sealant 74 as shown ln Figure 22.
Since a spacer made of metal is itself moisture impervious, the need for a moisture resistant seal in an embodiment employing a metal spacer is primarily to resist moisture penetration around the spacer.
Thus, in Figure 23, a metal spacer 50, as described in connection with the Figure 15 embodiment, is sealed to pane 30 with a layer o~ moisture ~L~6~

resistant material 75. The metal spacer and the layer 75 together p~esent a moisture resistant barrier in the path of moisture penetration in the direction parallel to the ma~or surfaces of pane 30. The same approach may be utlliæed with a relatively moisture transmit-table organic spacer if the spacer is first made moisture resistant by wrapping it with a moisture resistant tape 76 as shown in Figure 24. The tape ls held in place on spacer 21 with spots or beads o~ adhesive 77. Tape 76 is preferably an essentially moisture impermeable material such as an aluminum foil or stxip.
The mounting procedures and the general configurations of the completed multiple glazed installations for the subassembly embodiments of Figures 19 through 24 are essentially the same as set forth above in connection with the ~igure 9 and Figure 16 embodlments.
It should be apparent that in any of the embodiments disclosed herein a second subassembly may be installed onto a previously mounted subassembly so as to create a triple glazed installation.
Alternatively, one subassembly itself may include two or more spaced panes.
~ach of the sealants, mastics, or adhesives employed in conjunction with this invention is pre~erably highly moisture resistant, i.e., characterized by low moisture vapor permeability so as to effect good moisture barriers and hermetic seals. In addition, they are also preferably characteriæed by excellent flexibility; cohesive and adhesive bonding; and teax, shear, peel, and tensile strength over a relatively wide range of expected operating temperatures, including temperatures from -60E to 140F. Furthermore, they should be essentially inert and unaffected by chemicals, e.g., cleaning solutions, air borne pollutants or the like, with which they may normally be expected to come into contact.
It should be understood, however, that in certain instances related to the location or use of the sealants, mastics, or adhesives in the structu~es disclosed, one o~ mo~e of the above characteristics or properties may be of more dominant importance than another or others and accordingly, the choice of mastic materials used may vary substan-tially. For example, moisture resistance is not a dominant requirement for mastic 22 in the subassembly of ~igure 2 because ribbon 20 in con-~unction with the other mastics can provide the desired protection against moisture penetration during shipping, storage, or after final installatlon to form a multlple glazed wlndow.
Although the present invention has been described with particular reference to the specific details of certain embodiments thereof, it is not intended that such details shall be regarded as limitations upon the scope of the invention except insofar as included in the accompanying claims.

_ 19 _

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An architectural glazing unit for converting installed glazing to multiple glazing, comprising:
no more than one transparent pane;
an elongated spacer element adjoining marginal portions of a first major surface of said pane around the perimeter of said pane, each longitudinal portion of said spacer element having a first surface and a second surface on opposite sides thereof, wherein said first surface faces said marginal portions of said pane in adjoining relation-ship thereto, and said second surface faces outwardly, away from said marginal portions of said pane;
a ribbon of essentially moisture vapor impervious material extending around the perimeter of the unit adhered to said second surface of said spacer element and overlying peripheral edge surface portions of said pane; and moisture-resistant sealant interposed between said ribbon and edge surface portions of said pane so as to provide adhesion and a hermetic seal therebetween.

2. The glazing unit of claim 1 wherein said spacer element is comprised of a flexible, moisture vapor transmittable, poly-meric material.

3. The glazing unit of claim 2 wherein a quantity of desiccant is included within said spacer element.

4. The glazing unit of claim 2 wherein said ribbon is comprised of flexible metallic material.

5. The glazing unit of claim 2 wherein said ribbon is adhered to and sealed to peripheral edge surface portions of said pane and to marginal portions of a second major surface to said pane.

6. The glazing unit of claim 2 wherein said sealant is comprised of a polymeric composition having a moisture vapor trans-mittance of less than about 15 grams of water per 24 hours per square meter for 1 mil thickness.

7. The glazing unit of claim 2 wherein said first surface of said spacer element is in direct, non-adhering contact with said marginal portions of said first major surface of said pane.

8. The glazing unit of claim 1 wherein said spacer element includes a rigid structure formed from essentially moisture vapor imper-vious material.

9. The glazing unit of claim 8 wherein said spacer element contains a quantity of desiccant.

10. The glazing unit of claim 8 wherein said ribbon is comprised of flexible material and is essentially moisture vapor impervious.

11. The glazing unit of claim 8 wherein said moisture resistant ribbon is adhered to and sealed to peripheral edge surface portions of said pane and to marginal portions of a second major surface of said pane.

12. The glazing unit of claim 8 wherein said sealant is comprised of a polymeric composition having a moisture vapor transmittance of less than about 15 grams of water per 24 hours per square meter for 1 mil thickness.

13. The glazing unit of claim 8 wherein said first surface of said spacer element is adhered to said marginal portions of said first major surface of said pane by means of a layer of adhesive interposed therebetween.

14. The glazing unit of claim 8 wherein said spacer element is comprised of a plurality of separate segments, each segment being affixed along one margin of said pane.