U.S. patent number 3,683,974 [Application Number 05/079,077] was granted by the patent office on 1972-08-15 for method for purging and filling multiple glazed units.
This patent grant is currently assigned to PPG Industries, Inc.. Invention is credited to Renato J. Mazzoni, Lester F. Schutrum, John L. Stewart.
United States Patent |
3,683,974 |
Stewart , et al. |
August 15, 1972 |
METHOD FOR PURGING AND FILLING MULTIPLE GLAZED UNITS
Abstract
A method for purging and filling a multiple glazed unit with a
fluorocarbon gas in which the unit is supported so that its pore
hole is located in an upper disposed region of the unit and, while
so supported, the gas is injected into the unit and air is
simultaneously displaced therefrom.
Inventors: |
Stewart; John L. (Apollo,
PA), Mazzoni; Renato J. (Tarentum, PA), Schutrum; Lester
F. (New Kensington, PA) |
Assignee: |
PPG Industries, Inc.
(Pittsburgh, PA)
|
Family
ID: |
22148273 |
Appl.
No.: |
05/079,077 |
Filed: |
October 8, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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845988 |
Jul 30, 1969 |
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Current U.S.
Class: |
141/4; 65/32.2;
156/109; 65/58 |
Current CPC
Class: |
E06B
3/6775 (20130101) |
Current International
Class: |
E06B
3/677 (20060101); E06B 3/66 (20060101); B65b
031/04 () |
Field of
Search: |
;52/171,172 ;53/88,112
;65/32,58 ;141/1,3,4,11,63,69,85,89,91,92 ;316/20,24 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Earls; Edward J.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No.
845,988, filed July 30, 1969, now abandoned.
Claims
We claim:
1. A method for purging and filling a multiple glazed unit having a
pair of glass sheets sealed together around their marginal edges to
provide an air space between the sheets and a pore hole located in
a marginal edge portion of the unit comprising supporting the unit
with said pore hole located in an upper disposed region of the unit
and injecting a fluorocarbon gas through said pore hole into said
space while simultaneously displacing air from said space through
said pore hole to the exterior of the unit.
2. The method according to claim 1 wherein said gas is injected
into said space for a time and at a rate sufficient to produce a
concentration of gas within said space of between 85 to 100 percent
by volume of gas based on the volume of the air space.
3. The method according to claim 2 which further includes the step
of controlling said time and rate of gas injection to produce said
gas concentration with 1.5 volumes of gas based on the volume of
the air space.
4. The method according to claim 1 wherein said unit is vertically
disposed.
5. The method according to claim 1 wherein said unit is
horizontally disposed.
6. The method according to claim 1 wherein said unit is disposed at
an angle between a vertical and a horizontal disposition.
Description
BACKGROUND OF THE INVENTION:
This invention relates to a method for purging and filling multiple
glazed, insulating units. More particularly, the present invention
relates to an improved method for purging and filling all-glass
multiple glazed units with a fluorocarbon gas and, thereafter,
sealing the gas within the units to improve their insulation
effectiveness, thus reducing heat loss due to indoor and outdoor
temperature differentials.
The term fluorocarbon, as used herein, is intended to include all
normally gaseous fluorine containing hydrocarbons having one to
four carbon atoms, including compounds which may contain other
halogen and/or hydrogen atoms in addition to the fluorine present.
Included among the fluorocarbon compounds that are contemplated
are: tetrafluoromethane, trifluoromethane, chlorotrifluoromethane,
hexafluoroethane, bromotrifluoromethane,
chlorodifluoromethane-chloropentafluoroethane,
chlorodifluoro-methane, chloropentafluoroethane,
dichlorodifluoromethane, 1,1-difluoroethane, vinyl fluoride,
vinylidene fluoride and mixtures thereof. These compounds are sold
as "Freon" fluorocarbons by E. I. DuPont DeNemours &
Company.
One commercially used process for making all-glass multiple glazed
units is broadly disclosed in U.S. Pat. No. 2,624,979. This process
proceeds by supporting two superposed sheets of glass, with the
upper sheet slightly larger than the lower sheet, in slightly
spaced relationship to each other, heating the margins of the upper
sheet until they droop and become welded or fused with the margins
of the lower sheet, pulling the upper sheet upwardly to provide a
chamber between the sheets, and abruptly increasing the air
pressure within the unit to effect filleting of the welded
connection between the sheets. The units have a least one pore
opening either in a face or an edge of the unit through which air
under pressure is introduced between the sheets to effect filleting
and, also, which thereafter allows for equalization of the pressure
of the air within the unit with atmospheric pressure during
annealing and cooling of the unit.
Subsequent to cooling the unit, additional treatment thereof
includes purging and filling the unit with dry air or gas and
hermetically sealing the unit. In the past, this purging and
filling operation has generally been accomplished while supporting
the unit on edge in a vertical position and purging and filling the
unit through a pore hole located at or near the bottom or
supporting edge of the unit.
It has been discovered, however, that when it is desired to purge
and fill these units with a low conductive, fluorocarbon gas, use
of the above-mentioned technique requires too great a time to
displace the air from within the unit and excessive amounts of the
purging and filling gas are wasted by release of this gas to the
work area surrounding the unit.
The present invention is directed toward ameliorating or overcoming
the foregoing problems. In accordance with the present invention,
each unit to be purged and filled with a fluorocarbon gas is
supported with a pore hole residing in the upper disposed region of
the unit. The fluorocarbon gas is then introduced or injected into
the interior of the unit through the pore hole while the air within
the unit is simultaneously displaced therefrom through the same
pore hole. By proceeding in the above manner, it has been
demonstrated that multiple glazed units can be purged and filled to
provide upwards of 85 - 100 percent by volume of a fluorocarbon gas
in the space between the glass sheets at least three to four times
faster and with minimal wastage or release of gas to the
surrounding environment than was previously possible when purging
and filling by the prior art technique.
The foregoing and other objects, features and advantages of the
present invention will become more apparent from the description
that follows when taken in conjunction with the drawing, in
which:
FIG. 1 is a perspective of a plurality of vertically disposed
all-glass, multiple glazed units being purged and filled in
accordance with this invention; and
FIG. 2 is a perspective of a plurality of horizontally disposed
all-glass, multiple glazed units being purged and filled in
accordance with this invention.
Depicted in FIG. 1 are a plurality of all-glass, multiple glazed
units 10 comprised of a pair of glass sheets 12 and 14 that are
welded together about their marginal edges. As illustrated, one of
the glass sheets, 12, of each unit 10 is provided with a pore hole
or purge hole 16 in a marginal edge portion thereof and in
communication with the interior of the unit.
In accordance with the present invention, units 10 are each
supported on edge in a vertical position on rack 18 so that the
pore hole 16 is located in the upper disposed region of the unit.
Also shown is a conduit or header 20 for the conduction of a
fluorocarbon gas to the vicinity of rack 18 and units 10. Header 20
is provided with a plurality of flexible plastic tubes 22 of
smaller outside diameter than the diameter of pore holes 16 and
which, as shown, are inserted in pore holes 16 and suitably
connected to the header 20 to conduct the fluorocarbon gas under
pressure from the header to the interior of each of the multiple
glazed units. As illustrated by the dashed arrows in FIG. 1, the
fluorocarbon gas is conducted downwardly into the lower disposed
region of units 10 to purge and fill each unit, and the air which
is thereby displaced from the unit, illustrated by the solid
arrows, escapes therefrom to the work area adjacent the units from
the generally annular space between tubes 22 and the side walls of
pore holes 16.
Shown in FIG. 2 is an alternate embodiment of this invention
wherein like numerals to those used in FIG. 1 have been employed to
designate like parts throughout the same. In FIG. 2, the units 10
are shown supported on one side thereof in a horizontal position on
a suitable table or conveyor support 24 so that pore hole 16 is
located in the upper glass sheet or upper disposed region of each
unit. As is again illustrated by the dashed arrows in FIG. 2, the
fluorocarbon gas is conducted to the lower disposed region of units
10 to purge and fill each unit and the air which is thereby
displaced from the unit, illustrated by the solid arrows, escapes
therefrom to the work area adjacent the units from the generally
annular space between tubes 22 and the side walls of pore holes
16.
To illustrate the improvement achieved by the practice of the
present invention, all-glass multiple glazed units of several
different sizes were purged and filled on the same equipment using
the "conventional" technique of purging and filling from the lower
disposed region of the units and the "improved" technique of this
invention of purging and filling from the upper disposed region of
the units. For any given size unit, the air space thickness
dimension from unit to unit was the same. The results of these
tests are as follows, with the purging and filling technique in
each case being indicated as "conventional" or "improved" in
accordance with the foregoing description of these techniques:
TABLE I
Purging and Filling with Chlorodifluoromethane
Gas Purge Concentration Gas and of Purging Purging Line Fill Unit
Size and Filling and Filling Pressure Time (Width .times. Gas in
Unit Technique (psi) (min.) Length) (% by
__________________________________________________________________________
Volume) Conventional 40 2 16".times.68 " 62.5 Conventional 40 6
16".times.68" 64 Conventional 40 10 16".times.68" 65.5 Improved 40
2 16".times.68" -- Improved 40 4 16".times.68" 100. Conventional 40
1 16-3/16".times.49" 74.5 Conventional 40 5 16-3/16".times.49" 80.6
Conventional 40 10 16-3/16".times.49" 84.5 Conventional 40 15
16-3/16".times.49" 87.4 Conventional 50 1 16-3/16".times.49" 76.5
Conventional 50 5 16-3/16".times.49" 81. Conventional 50 10
16-3/16".times.49" 83.7 Conventional 50 15 16-3/16".times.49" 84.5
Improved 25 5 16-3/16".times.49" 100. Conventional 25 4
16-1/2".times.49" 72.3 Conventional 25 4 16-1/2".times.49" 66.
Improved 25 2.2 16-1/2".times.49" 96. Improved 25 2.2
16-1/2".times." 93.8 Conventional 25 7.75 16".times.68-7/8" 53.7
Conventional 25 7.75 16".times.68-7/8" 54.5 Conventional 25 10.5
16".times.68-7/8" 55. Conventional 25 10.5 16".times.68-7/8" 54.4
Improved 25 3 16".times.68-7/8" 95. Improved 25 3 16".times.68-7/8"
94.8 Conventional 25 23.5 50".times.65-1/4" 62.2 Conventional 25
23.5 50".times.65-1/4" 58.8 Conventional 25 29.5 50".times.65-1/4"
50.6 Conventional 25 29.5 50".times.65-1/4" 54.4 Improved 25 8.9
50".times.65-1/4" 91. Improved 25 8.9 50".times.65-1/4" 93.2
__________________________________________________________________________
It will be evident from the foregoing that, for a given gas line
pressure, the improved purging and filling process of this
invention provides upwards of 85 - 100 percent by volume of
chlorodifluoromethane gas in the space between the glass sheets, at
least three to four times faster than was possible when purging and
filling by the conventional method. In fact, using the improved
purging and filling process of this invention, it was found that,
at a gas line pressure of 25 p.s.i. or above, 90 percent
concentration of gas within a unit was easily obtained with just
1.5 volume changes, an accomplishment not capable of being
duplicated when purging and filling by the conventional method.
Moreover, in practicing the improved process of this invention, gas
chromatographic analysis of air samples taken in the environment
surrounding the purging and filling operation will show that, as
purging and filling proceeds towards 100 percent, the wastage or
release of purging and filling gas to this environment is
substantially less than when purging and filling by the
conventional method. Thus, greater economy of operation is readily
achieved pursuant to this invention.
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. For example, it will be
evident that, so long as the pore hole is located in an upper
disposed region of the unit, the general disposition of the
multiple glazed unit itself can vary or be varied from the vertical
and horizontal dispositions shown to any angular disposition
therebetween.
* * * * *