Refrigerated display equipment

[57] ABSTRACT

Refrigerated display equipment is provided with a refrigerated space having an access opening for customers at the front thereof together with separate air duct means through which air is passed from inner and outer return air inlets to inner and outer air discharge means for establishing an air curtain moving across said front access opening and embodying at least two layers of air at least the inner one of which layers is refrigerated air. The equipment is further provided with an access opening for service personnel at the rear of the refrigerated space and the air duct means through which air is passed from the return air inlets to the air discharge means each include a portion which is located adjacent the access opening at the rear of the refrigerated space.

Claims, 7 Drawing Figures

<img file="US3756038A_D0001.tif" />

PATENTEDSEP 41973

3.756,038

SHEET 1 OF 4

<img file="US3756038A_D0002.tif" />

FIG I

PATENTEOSEP 41973

3,756,038

SHEET 2 OF 4

<img file="US3756038A_D0003.tif" />

<img file="US3756038A_D0004.tif" />

PATENTEDSEP 41973

3,756,038

SHEET 3 OF 4

<img file="US3756038A_D0005.tif" />

FIG 4

PATENTEDSEP 41973

3,756,038

SHEET U OF 4

<img file="US3756038A_D0006.tif" />

3,756,038

These results are preferably attained by providing refrigerated equipment having front and rear access opening to a refrigerated space, with two or more separate air duct means extending from inner and outer return air inlets adjacent one edge of a front access opening for customers to inner and outer air discharge means arranged to direct air toward the return air inlets in the form of a multiple layer air curtain. At least the inner layer of air forming the air curtains is refrigerated whereas an outer layer of air forming the air curtain has a temperature somewhat higher than the refrigerated air layer but below the ambient air temperature.

THE DRAWINGS

FIG. 1 is a vertical sectional view of a typical form of equipment embodying the present invention;

FIG. 1A is a perspective illustrating the lower end of the vertical portion of the second air duct means of the equipment shown in FIG. 1;

FIG. 2 is a horizontal sectional view taken on the line 2—2 of FIG. 1;

FIG. 3 is a horizontal sectional view taken on the line 3—3 of FIG. 1;

FIG. 4 is a vertical sectional view similar to FIG. 1 illustrating an alternative embodiment of the invention;

FIG. 5 is a view similar to FIG.4 illustrating a further alternative embodiment of the invention, and

FIG. 6 is a view illustrating a portion of another alternative construction embodying the present invention.

In that form of the invention chosen for purposes of illustration in FIGS. 1, 2 and 3 of the drawings the equipment embodies insulated top, bottom and rear walls 2,4 and 6 respectively extending about a refriger1

REFRIGERATED DISPLAY EQUIPMENT

FIELD OF INVENTION

It is common practice today to provide refrigerated display equipment with a refrigerated space having an access opening for customers at the front thereof and to establish an air curtain moving across the access opening from inner and outer air discharge means to inner and outer return air inlets. In this way an air barrier embodying multiple layers of air is established and it is usual to refrigerate the inner layer of air in the air curtain to provide a desired low temperature in the refrigerated space whereas an adjacent layer of air in the air curtain may have a somewhat higher temperature than the refrigerated layer of air and serves to reduce the loss of refrigeration from the refrigerated air to the ambient air in front of the case. Typical equipment of this type is disclosed in U.S. Pat. Nos. 2,862,369; 3,060,253; 3,134,243;

3,365,908 and 3,528,258; for example.

It has further been suggested heretofore that refrigerated cases having an access opening for customers at the front of a refrigerated space may also be provided with an access opening for service personnel at the rear of the case to enable such personnel to restock the shelves within the refrigerated space, as exemplified by U.S. Pat. Nos. 2,923,137; 2,993,349; 3,044,274 and 3,063,255.

However, those constructions which have an access opening at the rear of the refrigerated space have not heretofore been provided with an air curtain for the front access opening embodying multiple layers of air maintained at different temperatures or including lay- _t7d sp’aceTin whYc?^!^ rtf nir /-»Ϊτ·ζ-·ιι1ο+ω&lt;-1 Γτ-λτύί inrtjar and air πΐίΓΠϋΓΟΡ ^{J J} ~ _

3,063,254;

3,103,796;

3,128,609;

3,304,736;

3,130,559;

3,304,740;

ers of air circulated from inner and outer air discharge means to inner and outer return air inlets within the confines of the case itself. As a result the air curtains used in equipment having a rear access opening for service personnel have not heretofore been very effective as an air barrier to prevent the loss of refrigeration to ambient air in the front of the refrigerated space. Moreover, a single layer air curtain at the front of an access opening to a refrigerated space tends to pick up and mingle with the ambient air carrying moisture to the refrigerating elements so as to require frequent defrosting thereof. Furthermore, such an air curtain is more readily deflected inwardly upon the opening of a door at the rear of the refrigerated space with the result there is a greater tendency for ambient air to enter the refrigerated space and cause moisture to condense on products being displayed and other surfaces with which it comes in contact.

The presence of doors at the rear of a refrigerated case also limits the area in which air ducts leading from &lt;- . .. - · · the lower to the upper portion of the case can be lo- ³³ Inner and outer return air inlets 22 and 24 respectively cated with the result that problems are presented in * ’ maintaining a uniform flow of air in an air curtain extending across the full width of the access opening.

In accordance with the present invention the foregoing difficulties and limitations inherent in constructions of the prior art are overcome and equipment is provided which affords access to a refrigerated space from both the front and rear thereof while providing a multiple layer curtain opposing the entry of ambient air into the refrigerated space through the front access opening and reducing the loss of refrigeration from the refrigerated space to the ambient air.

cated for the display of meats or other products to be refrigerated. The front of the refrigerated space is provided with an access opening 12 for customers whereas the rear of the refrigerated space is provided with an 40 access opening 14 for service personnel. The rear access opening is normally closed by sliding, roll-up, or swinging doors 16 so that the articles on display can be replenished or rearranged as desired and the needs of the customers can be served by persons located in a 45 service area at the rear of the case.

In order to shield the display space 8 from ambient air in the front of the case an air curtain is established across the front access opening 12. In order to render the air curtain more effective it embodies at least two ⁵⁰ adjacent layers of air travelling in parallel relation but having different temperatures. For this purpose an inner air discharge means 18 and an outer air discharge means 20 are located adjacent one side or edge, and preferably the upper edge, of the access opening 12.

are positioned adjacent the opposite or lower edge of the access opening in position to receive air directed across the access opening from the inner and outer air discharge means 18 and 20. In this way the air disharged from the inner discharge means 18 to the inner return air inlet 22 will form the inner layer 26 of an air curtain 28 whereas air from the outer air discharge means 20 and flowing to the outer return air inlet 24 will form an outer layer 30 of the air curtain. The two layers of air are adjacent and positioned between the refrigerated space 8 and the ambient air 32 in front of the case.

3,756,038

The inner return air inlet 22 is connected to the inner air discharge means 18 by a first air duct means which includes the return air passage 34 extending downward from inner return air inlet 22 to a lower plenum chamber 36 directly beneath the refrigerated space 8, together with vertically extending air duct portions 38 communicating at their upper ends with an upper plenum chamber 40 directly above the refrigerated space 8. The air in the first air duct means then flows from the upper plenum chamber 40 to the inner air discharge : means 18 to form the inner layer 26 of air curtain 28. In a similar way a second and separate air duct means extends from the outer return air inlet 24 through a return air passage 42 to a bottom plenum chamber 44 below the lower plenum chamber 36 and to vertically extending air duct portions 46 communicating at their upper ends, with a top plenum chamber 48 above the upper plenum 40. The air then passes from top plenum chamber 48 to the outer air discharge means 20 to form the outer layer 30 of air curtain 28.

Refrigerating means 50 are located in the first air duct means for reducing the temperature of the air circulated therethrough and about the refrigerated space so as to maintain said space at a desired low temperature. Thus, an evaporator 50 and blowers 52 are located in the upper plenum chamber 40 and extends substantially the full length of the plenum chamber. The evaporator preferably includes longitudinally extending coils with a plurality of parallel fins extending from the rear toward the front of the plenum chamber and is located directly above the refrigerated space 8 and in heat exchanging relation therewith. If desired a further evaporator 54 and blower 56 may be located in the lower plenum chamber 36 directly below the refrigerated space. The air thus refrigerated and circulated serves as the primary source of refrigeration for the refrigerated space 8 and the articles on display therein.

The air forming the outer layer 30 of the air curtain 28 is circulated through the second air duct means by means of blowers 58 which preferably are located within outwardly flaring hoods 60 at the lower ends of the vertically extending portions 46 of the second air duct means as shown in FIG. 1A. The hoods 60 serve to draw air from substantially the entire width of the bottom plenum chamber 44. The hoods 60 project inwardly at the rear of the lower plenum chamber 36 and the blowers 58 may be inserted into the hoods from the lower plenum chamber through openings 62. For this purpose a unit of the type disclosed in copending application Ser. No. 248,826 filed May 1, 1972 may be used and provided with a closure 64 for the openings 62 so as to isolate the blowers 58 from the lower plenum chamber 36.

The vertically extending portions 38 and 46 of the first and second air duct means are preferably arranged on the inner side of the insulated rear wall 6 of the case and form columns or mullions 66 located between and on opposite sides of the rear access openings 14 in the rear wall of the case as shown in FIGS. 2 and 3. Sliding or movable doors or windows 16 for the access openings 14 close the rear of the refrigerated space 8 while enabling service personnel at the rear of the equipment to replenish articles on the shelves 10 in the refrigerated space. The doors or windows 16 in the access openings 14 are preferably slidable along tracks 70 at the rear of the columns or mullions 66 at opposite sides of the access opening. The vertically extending air duct portions 38 and 46 then will be located in front of such doors so the vertically extending duct portions will be located entirely within the confines of the case and in direct heat exchanging relation with the refrigerated space 8 to aid in lowering the temperature of the air therein and reducing refrigeration loss to the exterior of the case from the duct means.

The partition 72 between the vertical portions 38 and 46 of the air duct means extends transversely of the mullions 66 and may be formed of metal. In the same way the partition 74 between the lower and bottom plenum chambers 36 and 44 and member 76 between the upper and top plenum chambers 40 and 48 may be formed of metal or they may include thermal insulating material or be otherwise formed to afford the deserved heat transfer effect. In this way the secondary air layer 30 or the air curtain 28, which consists of air circulated through the second air duct means will be cooled to a temperature below that of the ambient air but above 20 that of the primary refrigerated air circulated through the first air duct means and over the evaporator 50.

In the preferred construction embodying the present invention the partition 74 between the lower plenum chamber 36 and the bottom plenum chamber 44 is removably held in place so that it can be readily taken out to provide access to the bottom plenum chamber 44 from the refrigerated space 8 for cleaning of the case and to provide access to the evaporator 54 and blower 56, if used.

The air drawn upward through the vertically extending portion 48 of the first air duct means by fans 52 is distributed laterally so as to flow substantially evenly over the coils and fins of the evaporator 50 within the upper plenum chamber 40. For this purpose it is desirable to arrange a plurality of fans 52 in spaced relation between the upper ends of the duct portions 38 and the plenum chamber 40. As shown in FIG. 3, for example, six such fans may be provided in a 12 foot case and dividers or baffles 78 may be positioned to aid in distrib⁴® uting the air more or less equally to each individual fan for passage over the evaporator. Furthermore, the inner air discharge means 18 to which air from the upper plenum chamber 40 and evaporator 5® passes is preferably provided with a honeycomb nozzle 80 that 45 additionally serves to equalize the flow of air throughout the length of the inner layer 26 of the air curtain 28.

The member 76 between the upper plenum chamber 40 and top plenum chamber is preferably inclined upward toward the insulated top 2 of the case so as to pro⁵⁰ vide a restricted passage 82 between the upper ends of the vertically extending portions 46 of the second air duct means and the outer air discharge means 20. This restriction together with a honeycomb type nozzle 84 in the discharge means 20 serves to effectively distrib⁵⁵ ute the secondary air forming the outer layer 30 of the air curtain substantially evenly across the access opening 12 at the front of the refrigerated space 8.

The upwardly inclined member 76 forming the top of the upper plenum chamber 40 is located above the evaporator 50 and has a forward part 86 inclined downward toward the inner discharge means 18. Defrosting means for the evaporator 50 are provided and may be of the hot gas or electrical type, here shown as electrical resistor elements 88 positioned adjacent the evaporator 50 for periodically defrosting the same. During such a defrosting operation the fans 52 are stopped and the air within the plenum chamber 4® is not circulated.

3,756,038 it is desired to permit refrigerated air to be circulated through the display space and shelves and about the articles on the shelves 10. In such cases the member 110 which forms the bottom of the upper plenum chamber 5 40 and defines the top of the refrigerated space 8 may be provided with openings 112 and a passage 114 for directing a portion of the primary air refrigerated by the evaporator 50 into the display space as indicated by the arrows 116. The air thus circulated within the dis10 play space will be drawn off through the inner return air inlet 22 for recirculation through the first air duct means by the fans 52 and/or the fans 56 when the latter are employed.

The further alternative construction illustrated in 15 FIG. 5 is similar to the construction shown in FIGS. 1, 2 and 3. However, the case is further provided with means for establishing an air curtain 118 adjacent the rear access opening 14 to reduce or prevent the entry of air from a rear service or storage area 120 into the refrigerated space 8 when the doors 16 at the rear of the display space are opened. For this purpose an evaporator 122 is supported near the ceiling 124 or elsewhere and provided with a blower 126 by which air is drawn from the service area and is passed over the evaporator 122 to air discharge means 128. The air discharge means may include two converging honeycomb type nozzles 130 and 132 located above the rear access opening 14 and directed downwardly to establish the rear protective air curtain 118. If desired the blower 126 may be controlled by a switch or other means 134 positioned to be actuated upon opening of one or more of the doors 16 which normally close the rear access opening 14 for service personnel. However, since the service area 120 may require at least limited refrigeration the evaporator 122 and blower 126 may be operated substantially continuously if desired.

As shown in the alternative construction of FIG. 6 the equipment may be provided with a duct 131 and a blower 133 operable to draw cool and relatively dry air ⁴⁰ from the storage area 120 and direct such air downward through a discharge nozzle or outlet 13 to form a protective layer of air 136 on the outer side of the layers of primary and secondary air 26 and 30 which make up the air curtain 28 directed across the front access ⁴5 opening 13 of the case. In such constructions it will not generally be necessary to employ the blower 92 of the construction shown in FIG. 1 by which ambient air is utilized in forming an outer protective layer of air for the air curtain.

While various embodiments of the present invention have been shown in the drawings and described above, it will be apparent that numerous changes and modifications may be made in the form, construction and arrangement of the various elements of the combination. In view thereof it should be understood that the particular forms of the invention herein disclosed are intended to be illustrative only and are not intended to limit the scope of the invention.