Information
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Patent Grant
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6722149
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Patent Number
6,722,149
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Date Filed
Tuesday, January 7, 200321 years ago
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Date Issued
Tuesday, April 20, 200420 years ago
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Inventors
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Original Assignees
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Examiners
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CPC
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US Classifications
Field of Search
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International Classifications
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Abstract
A refrigerated merchandizer includes a display case defining a product display region having an open-front isolated from the ambient air of the store by means of a downwardly directed inner air curtain of relatively cold refrigerated air and a downwardly directed outer air curtain of relatively warmer air. The outer curtain of relatively warmer air is directed downwardly and outwardly away from the inner air curtain of relatively cold air at a divergent angle with respect to the inner air curtain.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to refrigerated display merchandisers of the type used in supermarkets, mini-marts, convenience stores and other commercial establishments for displaying and merchandising refrigerated or frozen products for sale. More particularly, the present invention relates to open-front refrigerated display merchandisers of the type wherein a curtain of cold refrigerated air is passed downwardly across the open front product display region of the merchandiser.
Refrigerated display merchandisers, also commonly referred to as display cases, having open front display regions are commonly used in supermarkets, mini-marts, convenience stores and other commercial establishments for displaying and merchandising refrigerated or frozen products for sale. The open front nature of such display cases permits the consumer to simply reach into the product display region to select and remove a product for purchase without the inconvenience of needing to open a door to access the product. Customarily, a curtain of cold refrigerated air is passed downwardly at a relatively high velocity across the open front of the display case to form an invisible boundary between the product display region and the region of the store in front of the display case. This air curtain not only helps retain cool refrigerated air within the product display region of the display case, thereby cooling the display product on the shelves of the display case, but also functions to isolate, to a certain extent, the product display region from the ambient air within the store. Ambient air that does enter into open product display region undesirably causes increased energy consumption by increasing the cooling demand on the refrigeration system associated with the display case. Further, such ambient air may also cause a local temperature rise within the product display region sufficient to result in an undesirable rise in product temperature that could adversely impact upon product quality.
A problem encountered with when passing a curtain of refrigerated air downwardly across the open front of the product display region of the display case lies in the entrainment of ambient air into the stream of refrigerated air forming the air curtain. Turbulence exists at the boundary between the relatively high velocity curtain air and the generally quiescent ambient air lying in front of the display case. As a result of such turbulence, some ambient air is undesirably entrained into the air curtain. Multiple air curtain display cases have been developed in the prior art to address this entrainment problem. For example, display cases having two adjacent, parallel, but independently generated, air curtains of refrigerated air are common in the art. Typically, such as disclosed by Maehara in U.S. Pat. No. 4,633,677, the outermost air curtain has a slightly higher temperature than the innermost air curtain, so as to protect the colder innermost air curtain from the impact of ambient air entrainment. However, such designs do not completely eliminate the intrusion of ambient air into the refrigerated air curtain.
Also, it is well known in the art to establish a third air curtain of relatively high velocity ambient air outwardly of one or two refrigerated air curtains as a means of reducing entrainment of ambient air from the store into the refrigerated air curtains. Abraham, in U.S. Pat. No. 4,267,706, discloses establishing an ambient air curtain outwardly of an innermost refrigerated air curtain, with the outer ambient air curtain being directed downwardly parallel to and adjacent to the inner refrigerated air curtain. Beckwith et al, in U.S. Pat. Nos. 3,648,482 and 3,850,003, MacMaster et al, in U.S. Pat. No. 3,827,254 and Roberts, in U.S. Pat. No. 5,345,778, each disclose establishing an ambient air curtain outwardly of a pair of refrigerated air curtains. The curtain closest the product display region of the display case is coolest, while the center curtain is at a temperature slightly warmer than the innermost curtain, but substantially cooler than the outermost ambient air curtain. The center curtain of warmer refrigerated air serves to buffer the innermost colder refrigerated air curtain from warm air intrusion from the outermost ambient air curtain. The outermost curtain of ambient air is directed substantially vertically downwardly, either parallel to and adjacent the center air curtain or slightly inwardly toward the center air curtain, so as to preclude refrigerated air from the center and innermost refrigerated air curtains from spilling out of the product display region of the display case. The outermost ambient air curtain itself ideally spills into the store near the base of the display case so as to not be drawn into the air return inlets through which the refrigerated air curtains return to the evaporator compartment. Although generally quite effective in reducing intrusion of ambient air into the colder innermost refrigerated air curtain, some intrusion into the center refrigerated air stream will occur. Further, providing three separate air flow circuits fro generating the three independent air streams increases the complexity and cost of the display case. Consequently, a need exists for a refrigeration system that addresses the problem encountered by the interaction of warm air outside of the display case and the air curtain without significant expense.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a refrigerated merchandiser including an improved performance multi-layer air curtain system. It is a further object of the present invention to provide a refrigerated merchandiser including a multi-layer air curtain system that is relatively less expensive than other multi-layer air curtain refrigerated merchandisers.
The refrigerated merchandiser of the present invention includes a display defining a product display region having an open-front isolated from the ambient air of the store by means of a downwardly directed inner air curtain of relatively cold refrigerated air and a downwardly directed outer air curtain of relatively warmer air. In accordance with the present invention, the outer curtain of relatively warmer air is directed downwardly and outwardly away from the inner air curtain of relatively cold air at a divergent angle with respect to the inner air curtain. In a preferred embodiment, the outer air curtain of relatively warmer air is directed downwardly and outwardly away from the inner air curtain at a divergent angle of about 5 degrees to about 55 degrees, and more advantageously at a divergent angle of about 25 degrees to about 50 degrees, and even more advantageously at an angle about 35 degrees to about 45 degrees.
The display case of the refrigerated merchandiser of the present invention has a first air outlet disposed in its top panel that directs relatively cold refrigerated air from the merchandiser's refrigeration compartment, cooled in a conventional manner, downwardly across the open-front viewing area of the display case to form an innermost air curtain. In addition to this first air outlet, a second air outlet is provided outwardly of the first air outlet to guide relatively warmer air generally downwardly to form an outer air curtain across the same viewing area. However, in contrast to conventional refrigeration display cases, the second air outlet includes guide vanes for directing the outer air curtain outwardly away from the inner air curtain at a divergent angle. The guide vanes may be permanently set at a predetermined divergent angle, or may be adjustable between a range of divergent angles so as to permit in-store optimumization.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment with reference to the accompany drawings wherein:
FIG. 1
illustrates a side elevation profile of a preferred embodiment of a refrigerated merchandiser having an open-front display case showing an outer warm air curtain and an inner cool air curtain directed across a product display region of the case in accordance with the present invention;
FIG. 2
illustrates a close-up view of the two outlets of the inventive display case that direct air across the product display region of the display case;
FIG. 3
illustrates a close-up view of an alternate arrangement of the two outlets shown in
FIG. 2
; and
FIG. 4
illustrates graphically the variation in air curtain performance as the angle of divergence changes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to
FIG. 1
, the refrigerated merchandiser
10
includes an outer cabinet
12
and an inner cabinet liner
20
that defines within its bounds an open-front product display region
30
. The outer cabinet has a base
13
, a rear wall
14
extending upwardly from the back of the base
13
, a top wall
15
extending forwardly from the rear wall and a pair of side walls
16
extending vertically from the base
13
to the top wall
15
and forwardly from the rear wall
13
. The inner cabinet liner
20
has a top panel
28
, a back panel
26
, a bottom panel
22
and opposed side panels
24
which together bound the open-front product display region
30
. Each of the cabinet base
13
, rear wall
14
, top wall
15
and side walls
16
is insulated, as in conventional practice, to thermally isolate the interior of the cabinet
12
, including the product display region
30
, from excessive heat transfer therethrough.
Perishable product
80
being merchandized may be displayed on shelves
12
disposed within the product display region
30
and upon the upper surface of the bottom panel
24
. The product display region
30
has an open front
25
so as to permit consumers to not only view, but also reach into the product display region
30
to select and remove items of product
80
that they desire to purchase. Product display region
30
is cooled in a conventional manner to a desired product temperature, typically to a temperature between −10° F. to less than about 40° F., depending upon what product is being merchandised therein and whether the product is frozen or non-frozen.
The refrigerated merchandiser
10
further includes a refrigeration compartment
40
, typically disposed in the portion of the display cabinet
12
between the base
13
and the bottom panel
24
, as depicted in
FIG. 1
, wherein components of the refrigerant system, typically a tube coil evaporator
50
and a air mover
60
, such as for example one or more fans, are housed. However, it is to be understood that the specific type of air mover employed is not relevant to or limiting of the present invention. As in conventional practice, refrigerant passing through the tubes of the evaporator
40
cools air passing over the surface of the evaporator tubes. The refrigerant is typically supplied from a remote refrigeration unit located elsewhere within the store. However, it is to be understood that the present invention may also be employed on standalone refrigerated merchandisers that include their own refrigeration unit for providing the cold refrigerant.
An air circulation duct
32
is formed between the rear wall
14
and the top wall
15
of the outer cabinet
12
and the back panel
26
and top panel
28
, respectively, of the inner cabinet liner
20
. Air mover
60
serves to direct air from air inlet
42
through the compartment
40
so as to traverse evaporator
50
, and thence through duct
32
to a first air outlet
34
. As noted before, this circulating air has been cooled to a desired temperature as it traverses the evaporator
50
. From the first air outlet
34
, the cool refrigeration air is directed via vanes
36
provided within the first air outlet
34
downwardly along first path
45
across the open front
25
of the product display region back to air inlet
42
. Thus, the refrigerating air is recycled and repeatedly recirculated through the compartment
40
and duct
32
to converse energy expended in cooling the refrigeration air. Further, through the afore-described cooling arrangement, a cool air curtain
55
is formed across the open-front product display region
30
from top to bottom thereof. To provide further cooling air directly to the product display region
30
, a plurality of openings may be provided in the back panel
26
through which a portion of cold refrigerating air circulating through duct
32
may pass directly into the product display region
30
. This refrigerating air will also be drawn by the air mover back through the air inlet
42
into the compartment
40
to be recirculated.
As shown in
FIGS. 1-3
, a second air outlet
70
is provided outwardly of the first air outlet
34
at the top front of the cabinet
12
. In contrast to existing refrigerated merchandisers, second air outlet
70
serves to direct relatively warm air generally downwardly along a second path
75
that diverges from the first path
45
followed by the cool refrigerating air. In this manner, a relatively warm outer air curtain
65
is formed outside, i.e. further away from the product display region
30
, of the relatively cool inner air curtain
55
. The relatively warm outer air curtain
65
serves as a buffer between the relatively cool inner air curtain
55
and the ambient environment of the store. Further, as the relatively warm outer air curtain
65
diverges from the relatively cool inner air curtain
55
the respective air curtains pass generally downwardly, the amount of entrainment of warm air from the outer air curtain
65
into the cooler inner air curtain
55
is minimized. Further, when the outer air curtain
65
reaches the base region of the display cabinet
12
, it passes outwardly into the store rather than into the air inlet
42
in the forward end of the base portion of the cabinet.
13
Consequently, the entrainment of warm air into the relatively cool inner air curtain and subsequent passage through inlet
42
into the compartment
40
is minimized, thereby reducing energy consumption in cooling the recirculating refigeration air.
As shown in greater detail in
FIG. 2
, the first air outlet
34
and second air outlet
70
are located at top and forward region of display case
12
, with the second air outlet
70
being located outwardly of the first air outlet
34
, that is, closer to the front of the display cabinet
12
. As noted previously, first air outlet
34
is in communication with duct
32
and directs relatively cool air driven by air mover
60
downwardly along path
45
across open front of the product display region
30
to form the inner air curtain
55
. The second air outlet
70
is in fluid communication with a source of relatively warm air and directs relatively warm air driven by a second air mover
72
associated therewith downwardly along path
75
to form an outer air curtain
65
that diverges from the inner air curtain
55
.
In the embodiment depicted in
FIG. 2
, a plenum chamber
72
provided at the forward lip of the top wall
15
of the cabinet
12
. The second air outlet
70
and an ambient air inlet
74
open into the plenum chamber
72
. An air mover
76
, such as an axial flow fan, is provided in operative association with the inlet
74
. In operation, the air mover
74
draws ambient air from the store into and through the plenum chamber
72
and thence out the second air outlet
70
to form the relatively warm outer air curtain
65
. The second air outlet
70
may, as shown in
FIG. 2
, lie in the same plane as the first air outlet
34
. In this case, the second air outlet
70
is provided with guide vanes
78
, positioned so as to direct the relatively warm air passing therethrough to form the outer air curtain
65
along path
75
so as to diverge from the inner air curtain
55
flowing along path
45
. The guide vanes
78
may be adjustable such that the angle at which the second air curtain diverges from the first air curtain may be selectively adjusted within a range of preselected angles. Alternatively, as illustrated in
FIG. 3
, second air outlet
70
may be disposed at an angle with the first air outlet
34
and provided with axial guide vanes
78
such that the outer air curtain
65
is naturally directed to diverge away from the inner air curtain
55
.
In accordance with another aspect of the present invention, the outer air curtain of relatively warmer air is directed downwardly and outwardly away from the inner air curtain at a divergent angle A of about 5 degrees to about 55 degrees, and more advantageously at a divergent angle A of about 25 degrees to about 50 degrees, and even more advantageously at an angle A about 35 degrees to about 45 degrees. Referring now to
FIG. 4
, the vertical axis thereof represents an entrainment factor developed to qualitatively determine the degree of entrainment of warm air into the cool air. The entrainment factor is the ratio of the difference between the measured temperature of the return air passing through the return air inlet
42
and the measured temperature of the cool refrigerated air discharging through the first air outlet
34
to the difference between the measured temperature of the warm air discharging through the second air outlet
70
and the measured temperature of the cool refrigerated air discharging through the first air outlet
34
. The lower the magnitude of the entrainment factor, the lesser the degree of entrainment of warm air into the return air. The horizontal axis represents the divergent angle A, that is the included angle between the inner air curtain
55
and the outer air curtain
65
as these air curtains diverge as they flow generally downwardly from the first air outlet
34
and the second air outlet
70
, respectfully. As seen in
FIG. 4
, the entrainment of relatively warm air into the return air stream entering the return air inlet
42
was minimized when the divergent angle A between the inner and outer air curtain was about 40 degrees. However, significant reductions in entrainment occurred over a wide range of divergent angles.
The aforementioned description is exemplary rather than limiting. Many modifications and variations of the present invention may be recognized by those skilled in the art in light of the above teachings that will fall within the spirit and scope of the present invention. The preferred embodiments of this invention have been disclosed. Accordingly, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.
Claims
- 1. A refrigerated merchandiser comprising;a display case having an exterior and an interior, said interior defining a product display region having an open-front viewing area; a first air outlet associated with said display case for directing a first air stream of relatively cooler air generally downwardly across the front viewing area along a first path; a second air outlet associated with said display case for directing a second air stream of relatively warmer air generally downwardly and outwardly across the front viewing area along a second path at a divergent angle with respect to the first path.
- 2. A refrigerated merchandiser as recited in claim 1 wherein the divergent angle ranges form about 5 degrees to about 55 degrees.
- 3. A refrigerated merchandiser as recited in claim 1 wherein the divergent angle ranges form about 25 degrees to about 50 degrees.
- 4. A refrigerated merchandiser as recited in claim 1 wherein the divergent angle ranges form about 35 degrees to about 45 degrees.
- 5. A refrigerated merchandiser comprising;a display case having an exterior and an interior, said interior defining a product display region having an open-front viewing area; a first air outlet associated with said display case for directing a first fluid stream generally downwardly across the front viewing area along a first path; and a second air outlet associated with said display case for directing a second fluid stream generally downwardly and outwardly across the front viewing area along a second path at a divergent angle with respect to the first path.
- 6. A refrigerated merchandiser as recited in claim 5 wherein the divergent angle ranges form about 5 degrees to about 55 degrees.
- 7. A refrigerated merchandiser as recited in claim 5 wherein the divergent angle ranges form about 25 degrees to about 50 degrees.
- 8. A refrigerated merchandiser as recited in claim 5 wherein the divergent angle ranges form about 35 degrees to about 45 degrees.
US Referenced Citations (11)