U.S. patent application number 10/897622 was filed with the patent office on 2006-05-18 for soft-coated glass pane refrigerator door construction and method of making same.
This patent application is currently assigned to Anthony, Inc.. Invention is credited to Paul J. Artwohl, Dennis Kato.
Application Number | 20060103269 10/897622 |
Document ID | / |
Family ID | 35907883 |
Filed Date | 2006-05-18 |
United States Patent
Application |
20060103269 |
Kind Code |
A1 |
Artwohl; Paul J. ; et
al. |
May 18, 2006 |
Soft-coated glass pane refrigerator door construction and method of
making same
Abstract
A door for a refrigerator display case is provided. The door
includes a glass panel having a surface coated with a
low-emissivity soft coating. A refrigerator display case is also
provided. The display case has a refrigerated enclosure and a door
with three glass panels. The middle glass panel is coated with a
low-emissivity soft coating.
Inventors: |
Artwohl; Paul J.;
(Flossmoor, IL) ; Kato; Dennis; (Huntington Beach,
CA) |
Correspondence
Address: |
JEFFER, MANGELS, BUTLER & MARMARO, LLP
1900 AVENUE OF THE STARS, 7TH FLOOR
LOS ANGELES
CA
90067
US
|
Assignee: |
Anthony, Inc.
San Fernando
CA
91342-5301
|
Family ID: |
35907883 |
Appl. No.: |
10/897622 |
Filed: |
July 23, 2004 |
Current U.S.
Class: |
312/116 |
Current CPC
Class: |
A47F 3/0434
20130101 |
Class at
Publication: |
312/116 |
International
Class: |
A47F 3/04 20060101
A47F003/04 |
Claims
1. A door for a refrigerated display case, said glass door
comprising a glass panel having a surface coated with a
low-emissivity soft coating.
2. The door of claim 1, wherein the emissivity of said coated
surface is not more than about 0.1.
3. The door of claim 1, wherein the emissivity of said coated
surface is not more than about 0.05.
4. The door of claim 1, wherein the emissivity of said coated
surface is not more than about 0.03.
5. The door of claim 1, wherein said glass panel is untempered.
6. The door of claim 1, wherein said door has a visible light
transmission greater than about 0.6.
7. The door of claim 1, wherein said door has a visible light
transmission of greater than about 0.7.
8. The door of claim 1, wherein said door has a visible light
transmission of greater than about 0.75.
9. The door of claim 1, wherein said surface has an uncoated
perimeter portion.
10. The door of claim 1, wherein said uncoated perimeter portion is
substantially the entire perimeter of the glass panel.
11. The door of claim 1, wherein said glass panel is
untempered.
12. A door for a refrigerated display case, comprising three glass
panels, each said panel having first and second surfaces, wherein
one of said surfaces of one of said panels is coated with a
low-emissivity soft coating.
13. The door of claim 12, wherein said three glass panels comprise
a first glass panel, a second glass panel and a third glass panel,
and wherein said second glass panel is located between said first
glass panel and said third glass panel.
14. The door of claim 13, wherein said first surface of said second
glass panel is coated with a low-emissivity soft coating.
15. The door of claim 13, wherein said first surface of said second
panel and said second surface of said second panel are coated with
a low-emissivity soft coating.
16. The door of claim 12, wherein said emissivity of said coated
surface is not more than about 0.1.
17. The door of claim 12, wherein said emissivity of said coated
surface is not more than about 0.05.
18. The door of claim 12, wherein said emissivity of said coated
surface is not more than about 0.03.
19. The door of claim 12, wherein the glass panel having the coated
surface is untempered.
20. The door of claim 12, wherein said door has a visible light
transmission greater than about 0.6.
21. The door of claim 12, wherein said door has a visible light
transmission of greater than about 0.7.
22. The door of claim 12, wherein said door has a visible light
transmission of greater than about 0.75.
23. The door of claim 12, wherein said coated surface has an
uncoated perimeter portion.
24. The door of claim 23, wherein said uncoated perimeter portion
is substantially the entire perimeter of the glass panel having the
coated surface.
25. The door of claim 12, wherein the glass panel having a coated
surface is untempered.
26. A refrigerated display case, comprising: a. a refrigerated
enclosure having an interior space and an opening; b. a door
connected to said refrigerated enclosure and movable from a closed
position to an open position, said door comprising a first glass
panel, a second glass panel, and a third glass panel, wherein said
first glass panel is distal from said interior space, said third
panel is proximate said interior space, and said second panel is
located between said first panel and said second panel, said second
panel further comprising first and second surfaces, wherein said
first surface faces said first panel, said first surface is coated
with a soft coating, and said coated first surface has an
emissivity of not more than about 0.1.
27. The refrigerated display case of claim 26, wherein said coated
first surface has an emissivity of not more than about 0.05.
28. The refrigerated display case of claim 26, wherein said coated
first surface has an emssivity of not more than about 0.03.
29. The refrigerated display case of claim 26, wherein said coated
first surface has an uncoated perimeter portion.
30. The refrigerated display case of claim 29, wherein the uncoated
perimeter portion is substantially the entire perimeter of the
second glass panel.
31. The refrigerated display case of claim 26, wherein said door
further comprises a spacer assembly between said first glass panel
and said second glass panel.
32. The refrigerated display case of claim 31, wherein said spacer
assembly comprises warm edge technology.
33. The refrigerated display case of claim 31, wherein said spacer
assembly abuttingly contacts said first surface, thereby defining a
contact location on said first surface.
34. The refrigerated display case of claim 33, wherein said contact
location of said first surface is not coated with said
low-emissivity soft coating.
35. The refrigerated display case of claim 31, wherein said spacer
assembly comprises a sealant adapted to form a seal between said
first glass panel and said second glass panel.
36. The refrigerated display case of claim 26, wherein the door has
a visible light transmission of greater than about 0.6.
37. The refrigerated display case of claim 26, wherein the door has
a visible light transmission of greater than about 0.7.
38. The refrigerated display case of claim 26, wherein the door has
a visible light transmission of greater than about 0.75.
39. A method of assembling a display case having a refrigerated
enclosure and an opening, the method comprising: a. providing a
door, said door comprising a glass panel having a surface, said
surface being coated with a low-emissivity soft coating. b. movably
covering said opening with said door.
40. A method of assembling a display case having a refrigerated
enclosure and an opening, the method comprising: a. providing a
door comprising three glass panels, each said panel having first
and second surfaces, wherein one of said surfaces is coated with a
low emissivity soft coating; b. movably covering said opening with
said door.
41. The method of claim 40, wherein said three glass panels
comprise a first glass panel, a second glass panel and a third
glass panel, and wherein said second glass panel is located between
said first glass panel and said third glass panel.
42. The door of claim 41, wherein said coated surface is said first
surface of said second glass panel.
43. The door of claim 41, wherein said coated surface is said first
surface of said second glass panel and said second surface of said
second glass panel is coated with a low-emissivity soft
coating.
44. The door of claim 40, wherein said emissivity of said coated
surface is not more than about 0.1.
45. The door of claim 40, wherein said emissivity of said coated
surface is not more than about 0.05.
46. The door of claim 40, wherein said emissivity of said coated
surface is not more than about 0.03.
47. The door of claim 40, wherein the glass panel having said
coated surface is untempered.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to door
constructions, and in particular, those used for refrigerated
display cases.
BACKGROUND OF THE INVENTION
[0002] Commercial refrigerators and refrigerated display cases
(coolers and freezers) are used in markets, food vending
operations, liquor stores and the like for preserving freshness and
attractively displaying products to the consumer. Typically, such
display cases have a refrigerated enclosure and an opening that is
sealed by a door that the consumer can open to retrieve the desired
product.
[0003] The energy required to operate refrigerated display cases
can be substantial. Thus, it is generally desirable to improve the
thermal performance of the display case by reducing the amount of
heat transferred from the surroundings to the refrigerated
enclosure. However, in addition to insulating the refrigerated
enclosure from ambient conditions, the display case doors provide a
customer with a means of viewing the refrigerated products. Thus,
it is desirable for the doors to allow as much visible light as
possible to pass from inside the enclosure to the customer, while
preventing the transmission of non-visible light from the
surroundings to inside the enclosure.
[0004] In addition, because the interior space of the refrigerated
enclosure is typically maintained at a temperature well below the
dew point of the ambient air, condensation frequently occurs on the
glass panes of the doors. Such condensation can drip onto the
floor, potentially causing a slipping hazard. It can also cause the
glass panes to fog up, thereby impairing the customers' ability to
view the products in the display case. Display cases have been
developed which use heated glass panes or heated display case
frames to reduce condensation. However, this approach also affects
the thermal performance of the display case by increasing the
energy required to operate it.
[0005] To address the foregoing issues, three-pack display cases
(i.e., display cases with three glass panes) with low emissivity
hard coated surfaces have been developed, as described in U.S. Pat.
No. 6,606,832. However, such door constructions require hard
coating two of the three panes in order to achieve the desired
thermal performance. As a result, the use of such hard coated
constructions is costly. Accordingly, a need has developed for an
improved door construction.
SUMMARY OF THE PREFERRED EMBODIMENTS
[0006] In accordance with a first aspect of the present invention,
a door for a refrigerated display case is provided. The door
comprises a glass panel having first and second surfaces, wherein
the first surface is coated with a low emissivity soft coating. In
describing the glass panels, the surface closest to the customer,
i.e. the outside, is referred to as the first surface, and the
inner surface is referred to as the second surface. The coated
surface preferably has an emissivity of not more than about 0.1. An
emissivity of not more than about 0.05 is more preferable and an
emissivity of not more than about 0.03 is especially preferred.
[0007] In accordance with a second aspect of the present invention,
a refrigerated display case having three glass panels is provided.
Each panel has first and second surfaces, and one of the surfaces
is coated with a low-emissivity soft coating. The coated surface
preferably has an emissivity of not more than about 0.1. An
emissivity of not more than about 0.05 is more preferable and an
emissivity of not more than about 0.03 is especially preferred.
[0008] In a preferred embodiment, the three panels comprise first,
second and third glass panels, wherein the first glass panel is
located nearest the customer. In additional preferred embodiments,
the first surface of the second panel is coated with a low
emissivity soft coating. In other preferred embodiments, the first
and second surfaces of the second glass panel are coated with a
low-emissivity soft coating.
[0009] In accordance with another aspect of the present invention,
a refrigerated display case is provided. The display case comprises
a refrigerated enclosure having an interior space and an opening. A
door is connected to the refrigerated enclosure and is movable from
a closed position to an open position. The door comprises a first
glass panel, a second glass panel, and a third glass panel. The
second panel comprises first and second surfaces, and the first
surface is coated with a low emissivity soft coating, wherein the
first surface has an emissivity of not more than about 0.1. An
emissivity of not more than about 0.05 is more preferable and an
emissivity of not more than about 0.03 is especially preferred. In
a preferred embodiment, the first surface of the second panel has
an uncoated perimeter portion.
[0010] In accordance with yet another aspect of the present
invention, a method of assembling a display case having a
refrigerated enclosure and an opening is provided. The method
comprises providing a door comprising a glass panel that has a
surface coated with a low emissivity soft coating and movably
covering the opening with the door.
[0011] In accordance with another aspect of the present invention,
a method of assembling a display case having a refrigerated
enclosure and an opening is provided. The method comprises
providing a door having three glass panels, each of which has first
and second surfaces. One of the surfaces is coated with a low
emissivity soft coating. The method further comprises movably
covering the opening with the door. In a preferred embodiment, the
second panel is located between the first and third panels and the
coated surface is the first surface of the second glass panel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention may be more readily understood by referring to
the accompanying drawings in which:
[0013] FIG. 1 is a perspective view of a portion of a refrigerated
display case used to illustrate the present invention.
[0014] FIG. 2 is a top plan view of a portion of a refrigerator
door in accordance with a preferred embodiment of the present
invention.
[0015] Like numerals refer to like parts throughout the several
views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] FIG. 1 depicts one-half of a refrigerated display case
incorporating two display case doors in accordance with a preferred
embodiment of the present invention. Display case 20 includes doors
30, mounted in surrounding frame 40 that defines an opening in
display case 20. Doors 30 have glass panels, generally depicted as
100. Glass panels 100 are designed to allow someone, such as a
supermarket customer, to view display items 60 on shelves 70. Items
60 may or may not be refrigerated items, such as frozen foods.
[0017] Using handles 48, doors 30 can be swung or slid open or
closed to alternately seal or unseal the interior space of display
case 20. Typical display cases include numerous other structures
for attaching doors 30 to display case 20, as well as features for
housing wiring, which are described in U.S. Pat. No. 6,606,832, the
disclosure of which is incorporated by reference herein.
[0018] Referring to FIG. 2, a top plan view of a preferred
embodiment of a refrigerator door is provided. Door 30 comprises
three glass panels, depicted as 120, 140 and 160. Door 30 is
typically mounted in a frame having a door rail that supports and
surrounds a glazing channel (not shown). The glazing channel may be
provided to support the glass panels and protect the edges thereof.
Instead of a glazing channel, a tape may be applied to the door
rail to protect the glass panes. The tape may be a foam or other
polymeric tape, and may be, for example, a film supported
polyolefin film tape or similar material.
[0019] Each glass panel has two surfaces, depicted as 121, 122,
123, 124, 125 and 126. In the embodiment of FIG. 2, surface 121
faces the customer and surface 126 faces the interior space of
display case 20. In a triple panel display case configuration, such
as the one shown in FIG. 2, the overall thickness of the glass pack
is preferably at least 11/4 inches, with the panels preferably
being 1/8 inch thick and the spaces between the panels preferably
being 7/16 inch.
[0020] Glass panels 120, 140 and 160 are preferably designed to
maximize visible light transmission from inside the case to the
customer, thereby improving the ability of customers to view
display items 60. However, it is also desirable to minimize the
transmission of non-visible light (i.e., ultraviolet and infrared
light) through glass panels 120, 140 and 160 from outside to inside
the case in order to improve thermal performance. In addition,
capturing the transmission of such non-visible wavelengths by the
glass panels beneficially generates heat within door 30 which can
drive off or prevent condensation on surfaces 121-126, further
improving product visibility. Coolers are a type of refrigerated
display case which operate at a temperature of approximately
38.degree. F. Freezers are another type of refrigerated display
case which operate below 0.degree. F. When the glass panels of such
display cases come into contact with ambient air, the relatively
colder glass panels can cause moisture in the air to condense on
the surfaces of the glass panels. Thus, it is desirable to use the
non-visible wavelengths of light to heat the glass panels, thus
reducing or preventing condensation.
[0021] It is preferred that door 30 have an energy consumption that
is reduced or entirely eliminated. Known doors for refrigerated
display cases frequently use heated door frames or glass panels to
reduce condensation. While atmospheric conditions in certain
geographic locations may make heated door frames or glass
desirable, the present invention eliminates or reduces the energy
consumed by such heated doors, while still reducing the
accumulation of condensation on glass panels 120, 140 and 160.
[0022] Prior techniques for improving thermal performance and
reducing condensation (or reducing the heating needed to avoid
condensation) involved the use of low emissivity hard coated glass
panes. However, in order to achieve the desired performance, such
hard coatings had to be applied to two of the six surfaces of glass
panels 120, 140 and 160. The present invention results from the
surprising discovery that when used in a triple panel refrigerator
door construction, a single glass panel coated with a low
emissivity soft coating can achieve the same performance as two
panels coated with a low emissivity hard coating.
[0023] As is well known to those of ordinary skill in the art, hard
coatings are those coatings that are applied during the glass
manufacturing process using chemical vapor deposition techniques.
The coating is applied when the glass pane is in its molten stage.
As a result, the coating fuses to the glass, becomes part of it,
and thus becomes hard. The present invention involves the use of
soft coatings. In contrast to hard coatings, soft coatings are
typically applied to the glass panel after it has solidified and do
not fuse to the glass. As used herein, the term "soft coating"
means a coating that is not diffused into the glass pane to which
it is applied.
[0024] As used herein the term "low emissivity" means an emissivity
of less than 0.2. Soft coated glass panes generally have lower
emissivities than hard coatings. However, they also suffer from
certain drawbacks. First, because they are not fused to the glass,
soft coatings are more vulnerable to physical damage, such as
scratching, than are hard coatings. Thus, soft coated glass must be
handled more carefully than hard coated glass. Second, the
processes used to temper glass panes are more costly and difficult
to perform when soft coatings are used. Industry standards for
display cases such as the one depicted in FIGS. 1 and 2 require
panels 120 and 160 to be tempered in order to minimize the
likelihood of breakage by and injury to consumers or employees.
Many soft coatings cannot undergo such tempering without degrading
or becoming damaged by the tempering process. While some soft
coatings can undergo tempering, soft coated panels typically must
be tempered more slowly than hard coated panels, increasing
processing costs. Even when such safeguards are implemented,
however, soft coated panels tend to have higher scrap rates than
hard coated panels.
[0025] To address the foregoing, low emissivity soft coating 240 is
preferably applied to surface 123 and/or 124 of glass panel 140, as
depicted in FIG. 2. It is especially preferable to apply soft
coating 240 to surface 123 only, as shown in FIG. 2. It is
preferred to apply soft coating 240 to inner panel 140 because
unlike panels 120 and 160, industry standards do not require panel
140 to be tempered. Preferably, the emissivity of coated surface
123 is not more than about 0.1. However, an emissivity of not more
than about 0.05 is more preferred and an emissivity of not more
than about 0.03 is especially preferred. Preferably, glass panels
120, 140 and 160 provide a visible light transmission through door
30 which is greater than about 0.6. However, a visible light
transmission of greater than about 0.7 is more preferred, and a
visible light transmission of greater than about 0.75 is especially
preferred.
[0026] Typical soft coatings comprise multiple layers of metal
oxides, and a variety of known soft coatings can be used with the
present invention, including SOLARBAN.RTM. 60, a product of PPG
Industries, Inc. and ACCLIMATE RLE 71/38, a product of Guardian
Industries Corporation.
[0027] Glass panels 120 and 140 are separated by spacing 125, and
glass panels 140 and 160 are separated by spacing 135. Spacings 125
and 135 can be filled with an inert gas to better insulate door 30
and improve its thermal performance.
[0028] A variety of inert gases can be used. However, Krypton,
Xenon, Argon or a mixture of 12% Air, 22% Argon and 66% Krypton are
preferred. The use of 100% Argon gas is especially preferred. As
shown in FIG. 2, spacings 125 and 135 can also be maintained by
spacer assemblies 180, which are preferably positioned around the
perimeter of glass panels 120, 140 and 160. Spacer assemblies 180
may be conventional spacers, such as the "comfort seal"
manufactured by TruSeal Technologies, Inc., but warm edge spacer
assemblies are preferred, as described in greater detail below.
Conventional sealant may be placed about the spacers to a level
flush with the outward facing perimeter edges 200, 204 and 206 of
glass panels 120, 140, and 160 or even over those surfaces if
desired.
[0029] Referring again to FIG. 2, spacer assemblies 180 preferably
use warm edge technology. As used herein, the term "warm edge
technology" refers to a spacer that has dessicant embedded,
surrounded or incorporated in a polymeric-based seal material.
Spacers incorporating warm edge technology may or may not
incorporate metal structures, metal foils or other inorganic
materials, but often do include such materials.
[0030] Spacer assemblies 180 preferably include an interior body
portion 340 formed of a dessicant matrix extending the width of the
spacing between adjacent glass panes. An outer-most edge of
interior body portion 340 is adjacent on each side thereof to
polyisobutylene sealant beads 360 which contact each adjacent glass
panel to form a seal therewith.
[0031] Spacer assemblies 180 also preferably comprise a vapor
barrier film 320 which may be a metal, Mylar, or other
vapor-impervious film extending the width of the spacer between
adjacent glass panels. The film 320 may be supported at its ends by
polyisobutylene sealant bead 360, as depicted in FIG. 2. The depth
of each bead 360 into the spacer from the adjacent glass panel is
preferably between 10 and 20 percent of the width of spacings 125
and 135. Sealant beads 360 help to seal between metal foil 320 and
adjacent surfaces of glass panels 120, 140 and 160, and contribute
to reducing vapor flow between the inside and outside of the glass
unit. In an especially preferred embodiment, there is little or no
structural metal (e.g., from the frame or door rails) in spacer
assembly 180.
[0032] Hot melt sealant 280, which is preferably hot melt butyl,
surrounds beads 360, film 320 and the outwardly facing portion of
interior body portion 340 to form a seal between adjacent glass
panels. Hot melt sealant 280 preferably extends from metal foil 320
to the outer most portion of spacer assembly 180. Sealant 280
extends on both the inside and outside surfaces of metal foil 320,
and width-wise from the surface of one glass panel to the surface
of the adjacent glass panel to seal them. Sealant 280 surrounds a
polymeric core 300 centered in the hot melt between the glass
panels. Polymeric core 300 preferably takes up about 60-80 percent
of each of the width-wise spacings 125 and 135 between adjacent
panels, with the hot melt separating the core from each of the
adjacent panels. Polymeric core 300 preferably extends from the
plane of outer peripheral edges 200, 204, and 206 approximately
two-thirds of the way into the hot melt. Polymeric core 300 is
preferably formed from a relatively firm thermoplastic or
thermosetting material, and may be formed from EPDM or other
suitable material. The core can also be completely surrounded by
hot melt 280. Such a warm edge technology spacer can be used
between each of adjacent glass panels 120, 140 and 160, or
alternatively, can be used between one pair of adjacent glass
panels, with a different type of spacer being used between the
other pair of panels.
[0033] As mentioned previously, soft coatings tend to be vulnerable
to oxidation. Such oxidation can also degrade the seal provided by
sealant 280. As a result, it is preferred to "edge-delete" the
coating from the glass to reduce the likelihood of oxidation. In
the embodiment of FIG. 2, coating 240 is not applied to surface 123
in the region adjacent to exposed edge 204 of glass panel 140. As
shown in the figure, it is especially preferred to apply coating
240 inward of spacer assembly 180 to further reduce the likelihood
of oxidation-induced degradation of the coating 240 and sealant
280.
[0034] Another example of a warm edge technology spacer is a spacer
such as that shown and described in U.S. Pat. No. 5,851,609,
incorporated herein by reference, and describing what is commonly
known as SWIGGLE.RTM. spacer by TruSeal technologies. However, in
the embodiments described herein for a refrigerator display case
door, the spacer element forming the undulating portion preferably
has a wave or peak amplitude, or spacing from the trough of one
part to the peak of the adjacent portion of the undulation, greater
than approximately 0.1 inch, and preferably in the range of 0.1 to
0.125 inch or more, to withstand the compressive forces that may
develop in a swing door under normal operating conditions, for
example, from opening and closing, racking or twisting as a result
of the door size and movement during normal operating and from the
application of the door frame itself about the edges of the glass
unit. One preferred amplitude may be in the range of about
0.125-0.2 inch with a possible thickness of about 0.160 to 0.170
inch. Alternatively or additionally, the wall thickness of the
metal or other material of the spacer element can be made thicker
to further withstand the compressive forces in the glass unit, even
though doing so would increase the cross sectional area for thermal
flow from one glass panel to the adjacent glass panel, thereby
tending to decrease the insulating properties of the glass unit.
However the integrity of the glass unit within the door frame would
be enhanced.
[0035] As mentioned earlier, it is desirable to increase the
transmission of visible light through glass panels 120, 140 and 160
of door 30 in order to improve the consumers' ability to view
display items 60. One of the known drawbacks of soft coatings is
their relatively poorer visible light transmission in comparison to
hard coatings. However, as mentioned previously, it has
surprisingly been discovered that the use of a single, soft coated
glass panel can achieve the same thermal performance as two hard
coated panels in a refrigerated display case. More preferably, when
used with a refrigerated case temperature of -12.degree. F. and a
room temperature of 75.degree. F., a three-pack refrigerator door
(i.e., a refrigerator door with three glass panels) with a single
soft coated panel in accordance with the present invention will
protect against condensation on the glass panels when the relative
humidity of the room exceeds 55%. By reducing the number of coated
glass panels, it has been found that a soft coated construction can
achieve an overall visible light transmission that is at least
equal to certain hard coated constructions wherein two of the glass
panels are coated.
[0036] The embodiments described above are exemplary embodiments of
a the present invention. Those skilled in the art may now make
numerous uses of, and departures from, the above-described
embodiments without departing from the inventive concepts disclosed
herein. Accordingly, the present invention is to be defined solely
by the scope of the following claims.
* * * * *