CA2270587A1 - Process of sealing insulating glass panel assemblies and apparatus therefor - Google Patents

Abstract

An improved process and apparatus for manufacturing an insulating glass panel assembly having at least two glass panels spaced apart one from the other by and adhered to a moisture resistant sealant composition, said process comprising the steps of (a) applying said sealant composition to a portion of at least one of said glass panels; (b) suitably positioning said glass panels one to the other in spaced apart relationship with said sealant therebetween; (c) heating said sealant to effect adhesion to said glass panels;
and (d) cooling said sealed insulating glass assembly; the improvement comprising selectively heating the sealant by selectively irradiating said sealant at an effective sealant absorbing but relatively low glass absorbing infrared wavelength selected from 0.8 - 1.3 microns, preferably, 1.1 - 1.2 microns, to effect selective heating of said sealant by said radiation. The process and apparatus obviates the need to provide a temporary aperture for air movement into and out of the air space in the assembly during manufacture and, accordingly, reduces expensive labour, time and storage costs. The invention further allows for large lite assemblies to be treated.

Description

PROCESS OF SEALING INSULATING GLASS PANEL ASSEMBLIES
AND APPARATUS THEREFOR
FIELD OF THE INVENTION
This invention relates to insulating glass panel assemblies, particularly to processes of sealing said assemblies, more particularly to said processes using infrared radiation, and apparatus therefor.
BACKGROUND TO THE INVENTION
Insulated glass panel or lite assemblies comprising at least two spaced apart lites of glass find extensive use in window frames and other assemblies. Such prior art insulating glass panel assemblies have the panels or lites of glass separated, for example, by a spacer system which may also provide support to the assembly and means to reduce ingress of moisture from the environment external of the assembly to within the air space trapped between the glass lites of the assembly.
One prior art assembly has a frame of adjacently parallel aligned spacers formed of 'U' shaped, hollow, aluminum members at the periphery of the assembly embedded into an outer rubber insulative mastic to which each of the lites at their periphery are adhered.
An alternative prior art assembly has a hollow, rectangularly-shaped rigid plastic tube in lieu of the aluminum members in addition to a rubbery insulative mastic material.
A further prior art assembly comprises the lites of glass being spaced apart by and adhered to a rubbery insulative mastic material within which is embedded an upstanding between-the-lites metal strip to provide additional support and enhanced reduction in moisture ingress.

In a yet further alternative prior art assembly, the rubbery insulative mastic is provided with an outer layer of metal foil to reduce moisture ingress.
A major problem found with air-containing insulating glass lite assemblies is condensation within the air space between the lites generated by outside temperature fluctuations. Thus, the aforesaid prior art assemblies are constructed with moisture resistant adhesive sealant compositions, optionally, provided with a metal strip or foil membrane to enhance resistance to moisture ingress.
However, in the manufacture of such insulating glass assemblies, the moisture resistant sealant compound is heated to its softening temperature after application to the periphery of a lite of glass and the whole assembly subjected to pressure at its periphery to effect permanent sealing of the lites to the sealant. The heating of the sealant is carned out generally by hot air convection through infrared heating, which also heats up the air trapped between the lites of the assembly to tyically about 170°F.
Subsequently, cooling of the assembly and the trapped air creates a negative air pressure within the air space which enhances moisture ingress. To obviate this condition, a small aperture is provided in the sealant material prior to the heating thereof and which is sealed after the assembly has cooled to ambient temperature. Clearly, this method of manufacture suffers from the significant cost disadvantages of involving additional process steps of providing and subsequently sealing the air aperture and additional time and storage space needed to allow for cooling of the sealed assemblies.
United States Patent No. 5,196,676, issued March 23, 1993 to Billco Manufacturing, Inc. Pa. U.S.A., describes use of infrared radiation emitters to provide short wavelength portions of the infrared spectrum at a wavelength of generally 1.6 mircrons in an oven unit comprising an oven box. The emitters are disposed within the oven box transverse to the conveyance means and with the ends of each emitter protruding through each sidewall of the oven box. The aforesaid emitters provide for a rapid response time for cooling down and a maximum amount of reflected radiant heat energy for heat treating the sealant material applied to the window units being conveyed therethrough.

However, aforesaid USP 5,196,676 does not address nor provided for oven units and methods of manufacture of air-containing insulating glass lite assemblies which obviate the aforesaid disadvantages resulting from the additional process steps due to the temperature of the lite assembly product exiting the oven box.
There is, therefore, a significant need for an improved process of manufacture and insulating glass panel assembly product which does not require the aforesaid additional process steps.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide improved processes of insulating glass lite assemblies, fully sealed in a single operation.
It is a further object to provide an improved process which offers improved handling of the assembly product and operating with concomitant savings in time, storage space and operating costs.
It is yet a fizrther object to provide improved apparatus for the manufacture of said insulating glass lite assemblies.
It is still yet a further object to provide an improved insulating glass lite assembly, fully sealed in a single operation.
Accordingly, in its broadest aspect, the invention provides an improved process for manufacturing an insulating glass lite assembly having at least two glass lites spaced apart one from the other by and adhered to a moisture resistant sealant composition, said process comprising the steps of (a) applying said sealant composition to a portion of at least one of said glass lites; (b) suitably positioning said glass lites one to the other in spaced apart relationship with said sealant therebetween; and (c) heating said sealant with infrared radiation to effect adhesion to said glass lites; the improvement comprising selectively heating said sealant by selectively irradiating said sealant at an effective sealant absorbing but relatively low glass absorbing wavelength selected from the range 0.8 - 1.3 microns.

A preferred source of radiation comprises a plurality of elongated halogen lamp emitters suitably spaced apart in parallel array offset to about 2 - 5°
from the longitudinal path of the direction of travel of lites within the oven. The lamps are preferably rated as 3800 watts and operate at about 500 - 625 volts, preferably about 570 volts, to provide an intense white light which provides the desired selective radiation wavelength.
Preferably, the irradiating wavelength is selected from the range 1.1 - 1.2 microns, which is removed from the typical > 1.6 micron wavelength provided by prior art infrared radiation heating sources, which are operated at less then 500 volts, typically, 480 volts, and generally provide a weak yellow emission at a filament temperature of about 1,600°C.
The operation of the emitters in a preferred embodiment according to the present invention provides a filament temperature of approximately 2,280°C. In a preferred embodiment of the invention enhanced efficient use of the emitter radiation is effected by providing each lamp with a highly polished reflective surface. To accomplish this, each cylindrical emitter tube is located at the "focal point" axis of the inner surface of a hollow semi-cylindrical member. To dissipate excess heat at the reflective surfaces, each reflector is air-cooled. Each emitter tube is dispersed at a suitable effective and selective heat sealing distance from the glass lite surface of about 8 - 12 cm.
Thus, the temperature increase of the glass lites, generally, is now due to a significant part by heat conducted from the heated sealant. The temperature of the air trapped within the sealed assembly is generally as low as 90 - 120°F, which provides for the most advantageous features of (i) ease of manual handling, (ii) reduced assembly cooling time for subsequent manufacturing operations or shipping, with attendant savings in costs, storage and the like, and (iii) allowing the assembly to be fully sealed in a single operation at the time of sealing the lites.
'The invention, thus, also provides a method as hereinbefore defined wherein the radiation is provided by first irradiation means and one of the glass lites has a first face distal from said sealant and its other face proximal to said radiation at a first proximal distance from said first irradiation means.
It will be understood by those skilled in the art that some heating of the glass lites is inevitable by the radiation and from the heated sealant, her se, and, indeed, is necessary S
for good adhesion. However, by selectively irradiating the sealant as aforesaid defined provides the significant advantages mentioned hereinbefore, including the total air sealing of the assembly in a single operation.
Further, most significantly, the invention provides for significant increased throughput rates of the assembly through the heating ovens. Typical rates of above 20 feet/minute can be achieved.
The aforesaid processes may be carried out with the glass lites conveyed along a linear, longitudinal path through a heated oven, which path may be horizontal, vertical or at any angle therebetween.
In a further aspect, the invention provides an improved apparatus for the manufacture of an insulating glass lite assembly having at least two glass lites spaced apart one from the other by and adhered to a moisture resistant sealant composition, said apparatus comprising (a) application means for applying said sealant to a portion of at least one of said glass lites;
(b) means for suitably positioning said glass lites one to the other in spaced apart relationship with said sealant therebetween;
(c) infrared heating means to heat said sealant to effect adhesion to said glass lites; the improvement comprising wherein said heating means comprise means for selectively heating said sealant by selectively irradiating said sealant at an effective sealant absorbing but relatively low glass absorbing wavelength selected from 0.8 - 1.3 microns to effect selective heating of said sealant by said radiation Preferably, the apparatus selectively generates wavelength in the range of about 1.0 - 1.2 microns, and more preferably 1.1 - 1.2 microns. In consequence that the temperature of trapped air in the assembly generally does not rise above 115°F under normal recommended operating conditions readily appreciated in the art, the sealant is applied to the full periphery of at least one of the lites without leaving an unneeded air hole as in prior art processes and apparatus.
In one embodiment, the apparatus as hereinabove defined has the infrared heating means comprising first heating means located operably adjacent at least one of the lites;

means for maintaining said at least one lite at a constant pre-selected distance from the first heating means; and adjustment means for maintaining the pre-selected distance constant irrespective of the glass thickness of the lites or thickness of the assembly.
In a preferred aspect the invention provides apparatus as hereinabove defined comprising an oven box comprising a pair of opposed sidewalk and an upstream entrance for receiving the glass lites and a downstream exit for the egress of the glass lites after heat treatment;
conveyance means for conveying the glass lite through the oven box from the entrance to the exit along a longitudinal path; and a plurality of the infrared emitters located within the oven box for heating the sealant.
Each of the emitters is elongated and has a longitudinal axis located essentially parallel to the longitudinal path. More preferably, the longitudinal emitter axis is at an angle of 2 -5° to the longitudinal path.
In a most preferred embodiment, the plurality of emitters comprises a first row of emitters located immediately adjacent and below the glass lites conveyed through the box and an upper row of spaced-apart emitters located immediately adjacent and above the glass lites.
The apparatus of the invention most advantageously provides, while not being limited thereto, for the use of elongated infrared emitters having a tubular length selected from about 40 cm. - 1 m.
The present invention emanates from the application of the recognition that by providing a filament temperature of, say, for example, about 2,300°C at an applied voltage of about > 570 volts, suitable selective infrared radiation is generated to efficaciously heat the sealant relative to the glass lites to provide reduced air temperature, within the glass lites assembly product to enable it to be readily handled, immediately, to the next location without the need for disadvantageous special handling, cooling and final hole sealing according to the prior art.
In a preferred embodiment, the invention provides apparatus as hereinabove defined wherein the conveyance means includes a plurality of spaced-apart hollow rollers extending between each side wall for conveying the lites therealong the longitudinal path from the entrance to the exit ; and cooling fluid feed means connected to the rollers to operably provide cooling fluid through the rollers.
In a more preferred aspect, the invention provides apparatus as hereinabove defined fizrther comprising air duct means within the oven adjacent the entrance and the exit; and wherein each of the emitters has terminal electrical contact means at each end disposed within the air duct means to operably effect cooling of the contacts.
Thus, the invention in a further aspect provides an improved insulating glass lite assembly coming from the apparatus and process of the invention in a single process not requiring a distinct hole-sealing step, subsequent to the cooled peripheral sealant layer of the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be better understood, preferred embodiments will now be described by way of example only, with references to the drawings, wherein Fig. 1 is a perspective view of a prior art insulating glass lite assembly;
Fig. 2 is a block diagram of the process steps according to the invention;
Fig.3 is a block diagram of the process steps according to an alternative process according to the invention;
Fig. 4 is a diagrammatic plan view of an oven according to the invention;
Fig. 5 is a diagrammatic perspective view, in part, of a reflector lamp arrangement of use in the invention; and wherein the same numerals denote like parts throughout the drawings.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE
INVENTION
Fig. 1 shows generally as 2 a prior art double pane window assembly having a pair of opposing glass lites 4 and 6 spaced apart by an inner peripheral layer of COMFORT
SEALTM (AFG GLASS) butyl sealant 8.

With reference to Fig. 2, a glass lite 24 is passed through flat glass washer 12 to a support table (not shown) in an application station 14, where a peripheral spacer layer of COMFORT SEALTM butyl-type mastic sealant is applied. Lite 24 is then passed to assembly station 16. A glass lite 26 is also passed through washer 12 to assembly station 16 where it is matched above lite 24. The assembly is then passed to an infrared heater 18 - press 20 assembly, wherein the sealant between lites 24, 26 is locally heated by the IR
radiation to its softening point and then pressed by multiple pressing rolls (not shown) of press 20 to effect adhesion to each of glass lites 24, 26. The pressed assembly is then conveyed to storage 22 by conveyer 28.
In an alternative embodiment shown in Fig. 3, the IR heating and pressing process step is preferably carried out with the assembly having each of the glass lites disposed vertically on one of its edges, instead of each glass pane disposed horizontally as described with reference to Fig. 2. Such a vertically arrangement reduces sagging of the glass lites during the sealing and pressing steps which sagging causes increased volume of air space in the resultant assembled product.
With reference now to Fig. 4, this shows a double array of tubular halogen lamp emitters 30 (Philips 3800T 3CLUB) located within an oven unit shown generally as 32 having a pair of sides 34, 36, entry side 38 and exit side 40. Emitters 30 form an upper parallel array 42 and offset by angle a° of about 3° from a line 44 - 44' perpendicular to sides 34, 36.
Each emitter has an outer diameter of about 1 cm. and length of about 106 cm.
Emitters 30 also form a similar lower array 46 but offset by angle -a°
of about 3° from perpendicular line 44 in the direction opposite to upper array 42. Each of arrays 42 and 46 are positioned to be about 8 - 12 cm. above and below, respectively, of the upper and lower surfaces, respectively of the glass lites passed through oven 32 on an array of hollow air-cooled steel rolls 48 in the longitudinal path direction of travel shown by arrow. Only the upper array 42 of emitters above the lites is shown.
In the embodiment shown, the glass lites are not as wide transverse to the direction of travel as the width of oven 32.
Each of emitters 30 has an electric contact at each end 43 which is located within air ducts 45 or 46, while each of rolls 48 is connected to a cooling fluid conduit 50.

In operation, cooling air is passed through ducts 45 and 50 to prevent excess heating of contacts 43 and premature destruction of emitters 30. Cooling air is also passed through rollers 48 to dissipate heat from rollers 48 heated during the sealing process by unwanted conductive and convective heating generated in the oven.
The efficacy of the apparatus and process of the present invention allows for the whole emitters and rollers to be contained within the oven such that emitters of additional length and novel disposition within the oven may be utilized.
In the embodiment shown in Fig. 4, each of upper array 42 and lower array 46 has fifteen 3800T 3CLUB halogen emitters receiving 570 input volts to generate a filament temperature of about 2,280°C.
With reference to Fig. 5, each lamp 30 is disposed at the "focal point" axis 'L' of an aluminum semi-tubular reflector 52 of a reflector array.
Glass lite throughput rates may vary depending on parameters such as glass thickness, sealant composition, interglass like distance and the like.
Rates typically range from 3 m - 8 m/minute. Each reflector has its inner curved surface 54 formed of highly polished light aluminum within an open rectangular body 56.
In alternative embodiments, the sealant composition may further comprise a dessicant, such as a fine particulate silica gel or molecular sieve such as a zeolite.
In yet further embodiments, the sealant spacer may be adhered to or embrace a support or moisture-ingress material, such as a rigid plastics material or a metal, such as aluminum foil or tape, provided such material does not overheat or otherwise react unfavourably to the infrared radiation.
Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalents of the specific embodiments and features that have been described and illustrated.

Claims (17)

1. An improved process for manufacturing an insulating glass lite assembly having at least two glass lites spaced apart one from the other by and adhered to a moisture resistant sealant composition, said process comprising the steps of (a) applying said sealant composition to a portion of at least one of said glass lites; (b) suitably positioning said glass lites one to the other in spaced apart relationship with said sealant therebetween; and (c) heating said sealant with infrared radiation to effect adhesion to said glass lites; the improvement comprising selectively heating said sealant by selectively irradiating said sealant at an effective sealant absorbing but relatively low glass absorbing wavelength selected from the range 0.8 - 1.3 microns to effect selective heating of said sealant by said radiation..

2. A process as defined in claim 1 wherein said radiation has a wavelength selected from the range 1.1 - 1.2 microns.

3. A process as defined in claim 1 wherein said irradiation step fully air-seals said assembly.

4. A process as defined in claim 1 wherein said steps (b), (c) and (d) are carried out with said assembly having said glass lites aligned in a vertical plane.

5. An improved apparatus for the manufacture of an insulating glass lite assembly having at least two glass lites spaced apart one from the other by and adhered to a moisture resistant sealant composition, said apparatus comprising (a) application means for applying said sealant to a portion of at least one of said glass lites;
(b) means for suitably positioning said glass lites one to the other in spaced apart relationship with said sealant therebetween;
(c) infrared heating means to heat said sealant to effect adhesion to said glass lites; the improvement comprising wherein said heating means comprise means for selectively heating said sealant by selectively irradiating said sealant at an effective sealant absorbing but relatively low glass absorbing wavelength selected from 0.8 - 1.3 microns to effect selective heating of said sealant by said radiation.

6. Apparatus as defined in claim 5 wherein said heating means comprises means for providing radiation at a wavelength selected from 1.1 - 1.2 microns.

7. Apparatus as defined in claim 5 wherein said application means comprises means for applying said sealant to the full periphery of at least one of said glass lites.

8. Apparatus as defined in claim 5 wherein said infrared heating means comprises first heating means located operably adjacent at least one of said lites;
means for maintaining said at least one lite at a constant pre-selected distance from said first heating means; and adjustment means for maintaining said pre-selected distance constant irrespective of the glass thickness of said lites or thickness of said assembly.

9. Apparatus as defined in claim 5 comprising an oven box comprising a pair of opposed sidewalls and an upstream entrance for receiving said glass lites and a downstream exit for the egress of said glass Rtes after heat treatment;
conveyance means for conveying said glass lite through said oven box from said entrance to said exit along a longitudinal path; and a plurality of infrared emitters located within said oven box for heating said sealant.

10. Apparatus as defined in claim 9 wherein each of said emitters is elongated and has a longitudinal axis which is located essentially parallel to said longitudinal path.

11. Apparatus as defined in claim 10 wherein said longitudinal axis of said emitters is at an angle of 2 - 5° to said longitudinal path.

12. Apparatus as defined in claim 9 where said plurality of said emitters comprises a first row of emitters located immediately adjacent and below said glass lites conveyed through said box and an upper row of spaced-apart emitters located immediately adjacent and above said glass lites.

13. Apparatus as defined in claim 9 wherein said emitter has a tube length selected from about 40 cm to about 1 m.

14. Apparatus as defined in claim 9 having an operable filament temperature of at least about 2,300°C at an applied voltage of about 600 volts.

15. Apparatus as defined in claim 5 wherein the conveyance means includes a plurality of spaced-apart hollow rollers extending between each side wall for conveying the lites therealong said longitudinal path from said entrance to said exit ; and cooling fluid feed means connected to said rollers to operably provide cooling fluid through said rollers.

16. Apparatus as. defined in claim 5 further comprising air duct means within said oven adjacent said entrance and said exit; and wherein each of said emitters has terminal electrical contact means at each end disposed within said air duct means to operably effect cooling of said contacts.

17. An improved insulating glass lite assembly as made by the process as defined in claim 3.