CA1290624C - Insulating glass unit - Google Patents

Abstract

ABSTRACT

A multiple pane glazing unit in which several glass panes are arranged in registering face-to-face relationship. The unit is provided with an integral resilient sealing band of thin flexible sheet material having a channel part of overall curved cross section bridging and lying between the edges of contiguous panes and lip parts overlying and secured to the edge surfaces of the panes.
The channel part is provided with transverse reinforcing corrugations.
The band, besides sealing in the space between the panes, holds the edges of the panes in spaced relationship while allowing limited relative resilient movement. The space between the panes may be and preferably is evacuated.

Description

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BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to insulated multi-pane glazed units.
Such units are used for residential and commercial construc-tion where controlled light transmittance and low sound and heat transmittance is desirable.

2. Description of the Prior Art Units of this type and their properties are described in the Canadian Building Digest, put out by the Division of Building Research, National Research Council of Canada, October 1963, in an article "Factory Sealed Double-Glazed Units" by Solvason and Wilson.
The structure described in this article is a typical insula-ting glass unit having two panes spaced-apart by a hollow metal spacer containing a desiccant and surrounded by one or two sealants between the frame and pane.
The prior art structure has a number of disadvantages. For example, the joint design predisposes the units to breakage because, as the glass moves due to barometric pressure and temperature changes, the spacer acts as a fulcrum point introducing stresses to the glass surface. This problem is discussed in an article in Glass Digest for February 15, 1982 by A. Risher Hall. The units also require desiccants which are expensive and also predispose the windows to breakage. The breakage problem is discussed in Glass Digest for December 15, 1981 by Richard Solvason, in a paper by C. J. Barry of Ford Glass Limited, presented to the Insulated Glass Manufacturers Association on June 6, 1985, in an article by Lynn Beason in Glass Digest for February 15, 1986, in an article by J. P. Ausikaitin in Glass Digest for October 15, 1982, and in an article by Helmut Brook in Glass Digest for June 15, 1986.
Also the seals on the units have short finite life due to moisture vapor and transmission properties of the organic sealants used. This problem is discussed in a paper delivered at the Sealed ~ 2~

Insulated Glass Manufacturers Association, June 1955 by Bachman, Glass Develop AB, Lund, Sweden and in a paper by Aulis Bertin delivered to the Insulated Glass Manufacturers Association, General Meeting, Toronto, January 10-11, 1979.
Conventional units also use hollow metal spacers (containing desiccants). These spacers are difficult to joint at the corners and decrease the visual area of the unit. They also provide fulcrum points giving ruse to the breakage problem described above. The spacers are usually made of aluminum which has a different coefficient of thermal expansion to the glass. The high heat conductivity of the aluminum reduces the thermal value of the unit and places internal stresses on the pane.
United States Patent 2,589,064, Drake (1952) discloses a multiple sheet glazing unit having separator means provided with flanges sitting on the edges of the panes and secured to them by metallic coatings and solder. Extending from the flanges between the panes is an undulating or accordian-like spacer. Applicant introduces this patent as a basis for explaining the distinction over it of the present invention. A main shortcoming of this structure is that the spacer cannot readily be brought around the corners and, therefore, cannot be used in a continuous band.
Similar shortconlings attach to the structures shown in U.S. Patents 4,312,457, Allaire (1982) and 4,393,105, Kreisman (1983).
Reference is also made to the applicant's prior Canadian Patent Application 432,631, filed July 18, 1983. This application discloses an assembly comprising two panes of glass of the same areal dimensions in registering parallel relationship with a plurality of non-rigid slightly compressed spacer members sandwiched between them. A cap of impervious material covers and adheres to the peri-pheral edges of the panes and bridges the gap between them to form a hermetically sealed chamber. The chamber is under partial vacuum so that implosive pressure urges the panes and cap together and the panes against the spacer members.
It is an aim of the invention to provide an effective insulated glazing unit using common readily available materials and technique and which avoids the disadvantages of prior art structures.
SUMMARY OF THE INVENTION
A double glazed unit, according to the invention, is made up of opposed glass panes connected and held apart by a sealing band of unique construction, which extends completely around the periphery of the unit and adheres to the edges of the panes. The sealing band is made up of a central channel part of overall curved cross section, located between the inside edges of the panes and an integral flange at each side of the channel part juxtaposed and secured to the edge surface of a pane. The channel part is provided with transverse corrugations which endow the band with strength and flexibility in all directions.
The invention also contemplates multiple glazing having more than two panes. In this event, the sealing band may have several channel parts intervened by an integral connecting web and integral terminal flanges for connection to the edges of the panes or alterna-tively may have inset inside panes and a single wide channel partbetween the outside panes.
The invention lends itself to multi-glazed structures with a simple air space between panes or structures in which the space or spaces are partially evacuated or gas filled. In the latter event, special spacing members are provided to maintain a given space between panes under the external pressure of the atmosphere urging them together.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the invention, it will be referred to in more detail by reference to the accompanying drawings, which illustrate preferred embodiments, and in which:
FIG. 1 is a fragmentary perspective view of a double glazed unit, according to the invention;

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FIG. 2 is an enlarged fragmentary perspective view showing a length of the edge sealing band used in the units Figs. 1 and 4;
FIG. 3 is a cross-section along the line 3-3 of Fig. 2.
FIG. 4 is a double glazed unit, according to the invention, which is under partial vacuum;
FIG. 5 is a fragmentary vertical cross-section through an evacuated triple glazed unit, according to the invention; and FIG. 6 is a fragmentary enlarged perspective view showing a length of sealing band for the triple glazed unit of Fig. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 shows a typical double glazed insulating unit, accord-ing to the invention. It is made up of a pair of opposed glass panes 15 and 17, intervened by a space 19. The panes are urged towards ; each other by atmospheric pressure acting on their outside surfaces.
The pane 15 has an inside surface 15a and peripheral edge surfaces 15b.
The pane 17 similarly has an inside surface 17a and edge surfaces 17b.
Preferably, the corners of the panes 15 and 17 are rounded off as shown.
A sealing band B is intimately bonded to the edge surfaces of the panes and bridges the gap 19 between them.
The sealing band B is an integral elongated thin impervious specially constructed band of flexible resilient sheet material having a central channel part 25 of curved cross section. The channel 25 is provided with a series of regular transverse corrugations, each pre-senting a series of valleys a and intervening crests b. The channel 25 is flanked at each side by a wide flat integral lip 29.
The sealing band B is applied to the glazing structure with the lips 29 lying flat on the edge surfaces 15b and 17b of the respective panes, and intimately bonded thereto to form sealing space 19 between the panes. The band B is dimensioned so that the channel 906;24 25 bridges the space 19 and just fits between the inside surfaces 15a and 17a, where they merge with the end surfaces 15b and 17b respectively.
Fig. 4 shows a typical double glazed evacuated insulating unit, according to the invention. Similar reference numerals have been applied to similar parts as in Fig. 1 but raised by 100. It is made up of a pair of opposed glass panes 115 and 117, intervened by partial vacuum space 119. The panes are urged towards each other by atmospheric pressure acting on the outside.
The pane 115 has an inside surface 115a and peripheral edge surfaces 115b. The pane 117 similarly has an inside surface 117a and edge surfaces 117b. Preferably, the corners of the panes 115 and 117 are rounded off, as shown in Fig. 1.
The panes 115 and 117 are held apart by a number of spacers A1 each made up of a small solid sphere 121, sandwiched between a pair of pads 123, each bearing against a surface 115a or 117a, as the case may be, of a pane.
A sealing band B1 is intimately bonded to the edge surfaces of the panes and bridges the gap between them, as will be clear from the description of Fig. 1.
Fig 5 shows a triple glazed structure, according to the invention. It includes spaced-apart glass panes 215, 216 and 217.
The panes 215 and 217 have inside faces 215a and 217a respectively and peripheral edge faces 215b and 217b. The intermediate pane 216 has opposed faces 216a and 216c and a peripheral edge face 216b which is inwardly spaced as compared to the edge faces 115b and 117b.
The panes are spaced-apart by spacers A2 in the form of malleable plastic discs 230 so as to maintain vacuum spaces 219 between the panes 215 and 216, and 220 between the panes 216 and 217.
The discs 230 between the center pane and respective outer panes are staggered to increase the conductive path through the unit. Where ball and pad spacers, as described above, are employed, a rigid ball of steel or ceramic bearing on hard pads preferably of steel or ceramic may be used. The pads are hard enough to prevent substantial penetration by the ball. The conductive path is minimized by the point loading between the ball and pads. The discs 230 are of high strength plastic material cleaned by plasma discharge to prevent out-gassing in vacuum. These plastics are slightly malleable to accommo-date a small amount of movement in the glass without fracturing it.
These plastics have low thermal conductivity.
Examples of suitable plastic are Tygon and polycarbonate resins.
The sealing band B2 is intimately bonded to the edges 215b and 217b and bridges the gaps created by the spaces 219 and 220.
The sealing band B2 is a thin flexible resilient strip of ; metal formed to include spaced-apart channel parts 225 flanked by a wide flat integral lip 229 which is bonded to an end edge face 215b or 217b, as the case may be.
Similarly, to the double glazed construction of Fig. 1, in ; the triple glazed construction, the sealing band B2 surrounds the edges of the structure with the lips 229 sitting on and intimately bonded to the edges 215b and 217b. The channel part 225 fits between the faces 215a and 216a, bridging the gap 219. The channel 226 fits between the faces 216c and 217a and bridges the gap 220 outside the edge of the intermediate pane 216.
Variables Glass The panes may be of any glass used for glazing or display screens, for example, any soda-lime or borosilicate glass, in com-bination with any type of coating or tinting. The panes may vary in thickness from 2 mm to 12 mm. The corners are radiused optionally between 3 mm and 12 mm. By way of example, a 3 mm clear, tempered, soda-lime glass is suitable. The edges should be ground slightly and the corners rounded to 3 mm to 12 mm radius. This is a standard procedure, prior to tempering, to reduce the risk of breakage and, at 90~i24 the same time, provides a suitable bonding surface for the sealing band.
Sealing Band The invention provides a spring band, resilient in all directions, to remove stress from the bond line when movement occurs.
This is accomplished by a sealing band of the following construction.
Stresses from accumulated thermal movement and wind loads are accommodated by flexing of the channel part of the sealing band.
Local stresses, directly at the bond side, are eliminated by matching the coefficients of thermal expansion of the sealing band with the glass and/or using bonds with enough malleability to allow ductile flow.
The shape of the band, according to the invention, also allows for continuous sealing around the unit without corner keys.
With the increasing use of higher performance glass, move-ment properties become more critical. For example, the inside pane can become very warm while the outside pane remains cooler, causing thermal movement. The rigid nature of a conventional seal often causes cracking of the inside panes. The seal of the invention does not.
Another type of stress is the result of the thermal gradient between the central area and the perimeter areas of the inner pane.
The applicant's sealing band being less thermally conductive, minimizes this problem.
The sealing band is preferably formed from malleable stain-less steel sheet of thickness from 4 to 20,000ths, desirably 5 to 7,000ths and having a range of Rockwell B hardness between 40 and 100, preferably 70 to 80. A preferred alloy is an annealed 304L
stainless steel.
Other metals may be used than those mentioned, for example, aluminum, low carbon steel, or copper. But, these metals are less desirable because of greater conductivity and corrodability and ~9~;2~

thermal coefficient of expansion.
A suitable sealing band may also be formed from plastic material. In fact, such a band is useful to increase the overall thermal performance of the insulating unit, by eliminating an otherwise conductive path from inside to outside. This also increases the strength of the unit by reducing temperature gradients within the glass surface. High strength plastic sheet having a thickness from 10 to 20,000ths with a metallic vapor barrier electroplated or vacuum deposited on one surface may be employed.
Suitable high-strength plastic sheel materials for the band are, for example, polyurethane or nylon which, at the thick-ness employed, are flexible. The plastics can be injection-molded or vacuum-formed to the desired shape.
Problems with undesirable deformation of the band during forming, e.g. puckering of the mounting lips, or otherwise, are overcome by a forming method constituting a part of this invention.
A typical band has a trough of width 1/2 inch and depth 1/4 inch and the spacing of the corrugations from crest to crest is about 0.05 inches and the depth from crest to trough may be substantially the same.
The trough may range in width from 1/8 inch to 2 inches, with the corrugations on the 2 inch trough being from 0.045 to 0.220 in depth and the distance between the crests being from 0.045 inches to 0.2 inches.
Bond To achieve an effective bond between the sealing band and the edge of the panes, it is desirable to select an alloy for the band which closely matches the coefficient of thermal expansion of the glass. For example, alloy #52 closely matches the coefficient of thermal expansion for soda-lime glass.

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Bonding can also be performed with a low temperature glass frit, e.g. a powdered high-lead glass, compounded to match the co-efficient of thermal expansion for appropriate glass. It is applied in a nitro cellulose vehicle and fuses at a temperature below that which will adversely affect the temper of the glass. The alloy is oxidized on the surface prior to bonding. The resulting oxide layer is soluble in the molten glass.
Aluminum can be directly bonded to glass using an electro-static process, but the aluminum band must be no thicker than 0.005 inches. At this thickness, the band yields before breaking the glass when movement takes place due to thermal mismatch.
Other mismatched materials, such as stainless steel, can be used with a graded seal. Interim malleable materials such as that used for common tin-lead solders can be used. This requires a metallizing of the glass to prepare it for fusing with the solder.
This can be done by atomic bombardment or vacuum metal deposits followed by electroplating. These films are too thin to present mismatch problems. It is likely that this process can be simplified by combining it with another phase of production - possibly metalliz-ing during tempering or the deposition of the low E coating. Heat can be supplied by laser, electron beam, induction, resistance or soldering irons.
The bonding of the band to the panes may also be performed as follows.
The peripheral edges of each pane is metallized with a metal layer chemically bonded thereto by ion-exchange. The lip or flange of thetinned band is then juxtaposed to the metallized edge surface of the pane and heat applied to fuse the band to the pane edge surface.
The resulting lamination is made up of the glass, the metallizing layer, tin-lead solder and the metal of the band. The coefficient of thermal expansion of the metal should be not more than 5% of that of the glass. The malleable nature of the solder inter-6~

layer allows for a greater mismatch to allow normal grades of stain-less steel to be used for the band. Preferably, the finished band is ultrasonically cleaned and tinned before its application. The metal band is juxtaposed to the edges of the pane, and heat and pressure is applied resulting in bonding.

Vacuum The vacuum required is 10 4 torr but to be safe the unit should be pumped to 10 6 since components will leak gas during the life of the unit. Special pumps and valves were used on the proto-type but in production this too would likely be accomplished in the coating stage for simplification. If coating is not applied in vacuum, a simple pinch-off tube could be used, as is done in the TV tube industry.
Baking of components is required to drive off surface gases.
This will require about 10 minutes, a short time compared to the 8 to 12 hour cure time required by conventional units. Helium penetra-tion of glass was pointed out as a potential contaminant of the vacuum but field studies indicate successful vacuum tubes in opera-tion for 50 years. Evacuated solar collectors, a very similar application, have a 10 year successful track record.
Getter Active metal getters absorb gases from the cavity during its life, helping to maintain the vacuum level. These are commercially available and activated by heat as a final production function. This is a well known science, backed up by 50 years of successful field operation.
Manufacture A preferred method of forming a metal sealing band is as follows.
A strip is run through a series of roll-forming dyes to provide the band with a trough which has a semi-circular or other-~L~ 3~i2~

wise suitable curve in cross-section. The cross-section may be semi circular, semi-oval or any other curved shape in which the curve is continuous from one lip or flange of the band to the other.
The resulting band is then subjected to a progressive dye-stamping operation to emboss the transverse corrugation in the trough part while reducing substantially to a minimum any change in the thickness of the band material.
A typical assembly method for an evacuated unit is as follows.
One pane is placed horizontally. lhe pads and balls are arranged into position by longitudinal support arms coming from the side. A second pane is placed horizontally on top of the assembly bearing the spacer.
The whole structure is prevented from moving horizontally by vertical supports. The getter is placed in the cavity. Weight is applied to the upper pane. The arms supporting the spacers are removed hori-zontally. The sealing band is then bonded at the peripheral edge of the panes, as described. A vacuum is drawn on the cavity through a tube. A pinch off tube as familiar to the electronics industry may be used. While the vacuum is being drawn the entire unit is heated to drive off surface gases. The tube is pinched to provide a vacuum tight seal. The getter is then activated by heating, for example, by radio frequency.
Glazed Structure ; In assembling the glazed structure, as shown in the previous Figures, an assembly jib is used to hold the pads and balls in place.
This is placed on the first pane and covered by the second pane.
Weights are applied to the second pane, the jig removed, and the perimeter is bonded. A tube through the perimeter band is used to evacuate the units.
Advantages The multi-glazed units of the invention have the following advantages:

~9(~624 l. Larger life expectancy due to decreased moisture vapor transmission rate of the seal.
2. Ease of manufacture because of the fewer components, the corner design and the nature of the sealing band. The structure lends itself to automated assembly.

3. Better thermal resistance due to decreased losses through the perimeter seal and spacer.

4. Greater resistance to breakage because the glass is relatively free floating.

5. Greater area of vision by reason of the elimination of desiccant and conventional spacer bar.

6. Cost advantage through elimination of desiccant and elimination of assembly labor.

7. The structure lends itself to gas-filling to improve thermal and sound insulation, being capable of retain-ing the gas permanently.

8. Transportation and installation is facilitated, the edges of tne glass being protected by the sealing band.
In summary, the applicant's evacuated unit introduces a new level of performance.

Claims (13)

1. A multiple pane glazing unit, comprising, a pair of opposed glass panes of the same areal dimensions arranged in registering spaced face-to-face relationship, each pane having parallel peripheral edges, an integral resilient sealing band of thin flexible impervious sheet material having a channel part bridging and lying between the marginal portions of the inside edges of the respective panes and lip parts overlying and secured to the edge surfaces of the outside pane, the channel part comprising a concavity extending from one lip to the other located in the gap between the inside surfaces of the opposed pane, the channel part being provided with transverse reinforcing corrugations, the band holding the edges of the panes in spaced relation-ship allowing them limited relative movement and enclosing with the panes an enclosed space.

2. A multiple glazing unit, as defined in claim 1, in which the enclosed space is under vacuum and there are spacers between the inside surfaces of opposed panes, each spacer being made up of a pair of pads with each pad bearing on the surface of one of the panes, and a ball-bearing between the respective pads.

3. A multiple glazing unit, as defined in claim 2, in which the spacers are in staggered relationship.

4. A multiple pane glazing unit, comprising, a pair of outside glass panes of the same areal dimensions arranged in registering spaced relationship and an intermediate pane of lesser area between the outer pane with its peripheral edges spaced inward from that of the outer pane, spacers between each outer pane and the intermediate pane, a thin flexible sealing band having a transversely corru-gated channel part extending from the inner edge face of each outer pane to the other outer pane and lips adhered to the edge faces of the outer pane, the space enclosed by the outer panes and sealing band being under vacuum whereby the outer panes are urged inward putting the spacers between the outer panes and the intermediate pane under compression.

5. A sealing band for a multiple glazed unit, comprising, a thin elongated strip of formable thermally resistant sheet material, the band being formed to have a central curved channel flanked at each side by a flat lip, the channel having a continuous series of transverse corruga-tions giving the band springiness and resilience in all directions enabling it to be applied about a small radius without buckling.

6. A sealing band, as defined in claim 5, made of metal having a thickness from four thousandths to ten thousandths of an inch.

7. A sealing band, as defined in claim 5, being of plastic having a thickness from ten thousandths to one-eighth of an inch.

8. A sealing band, as defined in claim 5, in which its resilience is such that it can be formed without a rounded corner having a radius of as little as one-eighth of an inch without buckling.

9. A sealing band, as defined in claim 5, in which the width of the channel is within the range of one-quarter of an inch to three-quarters of an inch.

10. A sealing band, as de-fined in claim 5, in which the depth from the top of the lip to the bottom of the corrugations is between one-eighth of an inch and one-half inch.

11. A sealing band, as defined in claim 10, in which the corru-gations have a pitch within the range from 0.050 inches to 0.0025 inches.

12. A sealing band, as defined in claim 10, in which the ratio between the pitch and depth of the corrugations is within the range 1:1 to 3:1.

13. A method of bonding a sealing strip to the edges of the panes of a multi-glazed unit, comprising, selecting a band of a metal alloy that has a thermal coeffi-cient of expansion close to that of the glass and pretinning the surfaces of the band which will contact the edge of the pane, metallizing the surface of the edges of the pane, juxtaposing the tin parts of the band to the metallized sur-face of the glass, fusing the tinning to complete the bond.