Untitled record

March 24, 1964

W. E. URAL

3,125,864

SELF-SERVICE REFRIGERATED DISPLAY CASE

Filed Oct. 16, 1962 2 Sheets-Sheet 1

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ATTORNEY

March 24, 1964 w. e. ural 3,125,864

SELF-SERVICE REFRIGERATED DISPLAY CASE

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ATTORNEY

United States Patent Office Patented Mar. 24, 1964

3,125,864

SELF-SERVICE REFRIGERATED DISPLAY CASE William E. Ural, Yardley, Pa., assignor, by mesne assignments, to The American Hardware Corporation, a corporation of Connecticut

Filed Oct. 16,1962, Ser. No. 230,852

Claims. (Cl. 62—256)

This invention relates to refrigerated display cases and is directed particularly to display cases which are open at the front for access to the display space and are arranged so that refrigerated air will flow downwardly adjacent the access opening or in front of shelves within the display space.

It has been common practice heretofore to provide refrigerated display cases with a relatively high back wall which may be provided with one or more vertically spaced shelves and to provide the front of the case with an access opening through which the shelves and display space are accessible. Such display cases are ordinarily provided with means for circulating refrigerated air downwardly adjacent the access opening in the front of the case to a return air duct opening adjacent the lower edge of the access opening.

The air thus circulated is sometimes presented in the form of a downwardly flowing air curtain or barrier which extends from a cold air outlet adjacent the upper edge of the access opening to an air return duct having a return air inlet adjacent the lower edge of the access opening. In other constructions cold air may flow forward from the back wall of the case or downward from the top of the case onto the shelves and thereafter cascade downward over the front edges of the shelves so as to flow downward adjacent the access opening in the front of the case. The air then is returned to be recooled and recirculated by passage to a return air duct having a return air inlet adjacent the lower edge of the front access opening.

When employing either type of air circulation, the downwardly flowing refrigerated air entrains or induces a downward flow of ambient air adjacent the front access opening. The air thus caused to flow downward is cooled by the transfer of a portion of its heat to the refrigerated air and by commingling therewith. As a result, the volume of air which flows downward toward the return air inlet is increased and generally exceeds the capacity of the inlet and return air duct. Therefore, substantial volumes of cool or relatively cold air spill forward out of the case causing substantial loss in refrigeration and creating an uncomfortably cold condition for the feet and legs of customers in the aisle in front of the case.

In accordance with the present invention, the uncomfortable conditions thus created are reduced or eliminated and a substantial saving in heat loss and an increase in the efficiency of operation of refrigerated display cases may be attained.

These advantages are preferably attained by providing open front display cases with one or more added or enlarged ducts or passages through which substantially all or the major portion of the cooled air flowing downward toward the lower edge of the access opening may be passed. A portion of such cooled air may then be refrigerated again and returned to the display space in a continually recirculating cycle as in conventional front access display cases. However, the other portion or remainder of the cooled air may be directed elsewhere to aid in air conditioning the store, to refrigerate other equipment, to cool a condenser, or it may be utilized in any other manner desired or simply discharged to some space where it will not be objectionable.

Accordingly, the principal objects of the present inven- tion are to prevent objectionable spilling over of cooled air adjacent the lower edge of an access opening in the front of a refrigerated display case, to assure more effective utilization of refrigeration in front opening display 5 cases, and to control the flow of ambient air which is cooled by refrigerated air flowing downward adjacent the front access opening in a refrigerated display case.

These and other objects and features of the present invention will appear from the following description thereof 10 wherein reference is made to the figures of the accompanying drawings.

In the drawings:

FIG. 1 is a vertical sectional view through a typical form of refrigerated display case embodying the present 15 invention;

FIG. 2 is a horizontal sectional view through the display case shown in FIG. 1;

FIGS. 3, 4 and 5 are sectional views illustrating various alternative embodiments of the present invention.

In that form of the invention chosen for purposes of illustration in FIGS. 1 and 2, the display case has a base or insulated bottom, a vertical rear wall 4 and a top or hood 6. The ends 8 of the case slope forward from the ends of the hood 6 to lower front wall 10 which defines 25 the lower edge of an access opening 12 in the front of the case. Shelves 14 are arranged in vertically spaced relation within the display space 16 and in position to be accessible through the front opening 12 of the case.

The bottom of the display space 16 is defined by a lower 30 floor or pan 18 which is spaced from the base 2 of the case so as to provide a refrigerating space 20 within which is located the evaporator 22 of a refrigerating unit. A second evaporator unit 24 is located at the rear of the display space and extends vertically adjacent the rear 35 insulated wall 4. A blower 26 is positioned between the evaporators 22 and 24 and serves to cause air to be circulated beneath the floor 18 of the display space and over the evaporators 22 and 24 so as to be forced upward through the refrigerated air duct 28 to the air discharge 40 spaces 30 beneath the shelves 14 and the air discharge space 32 beneath the hood 6.

The refrigerated air is thus caused to flow forward and downward over the articles in the display space 16 and located on the shelves 14. The air then flows forward 45 to duct means 34 located at the rear of the lower front wall 10 of the display case and below the front access opening 12. In so doing, the refrigerated air protects the articles on display from the ambient air in front of the case and forms an air curtain or barrier 36 of refriger50 ated air moving downward adjacent the access opening 12. This movement of the air establishing the air barrier 36 serves to cause the ambient air adjacent and in front of the access opening 12 to give up heat by conduction to the air of the barrier 36 and also causes some of said air 55 to be entrained and mingle with the air of the barrier 36. In this way, an induced stream of the ambient air 38 is created adjacent the access opening 12 substantially increasing the volume of the air flowing downward toward the duct means 34 adjacent the lower edge of the access 60 opening 12.

In a typical embodiment of the invention as shown in FIG. 1, the display case may be used for the refrigeration and display of frozen foods. In such a case, the refrigerated air issuing from the spaces 30 and 32 to 65 the display space 16 may be at a temperature of about —10° F.; whereas, the ambient air may be 70° F. The temperature of the air in the barrier 36 will then increase as it flows downward by reason of the absorption of heat from the ambient air and the mingling of ambient 70 air from the induced air stream 38. As these two streams of air flow downward, the temperature of the refrigerated air will be raised and the temperature of

3,125,864 the ambient air will be lowered until they reach the lower edge of the access opening at temperatures of, say +10° F. and +40° F. respectively. However, the volume of these combined streams of air will be nearly twice the volume of the refrigerated air which was discharged into the display space from the spaces 30 and 32 beneath the shelves. As a result, there would be a tendency for the induced stream of air 38 at a temperature of only about 40° F. to spill out over the lower front wall 10 of the display case at the lower edge of the access opening 12. It is the spilling of this cold induced air which has heretofore been found objectionable because of the loss of refrigeration and the chilling of children and the feet of adults or the legs of customers wearing shorts or having no stockings.

In accordance with the present invention, the duct means 34 adjacent the lower front wall of the display case has a greater capacity or cross section than the duct 28 at the rear of the case through which the refrigerated air from the evaporators 2'2 and 24 are passed to the discharge spaces 30 and 32 beneath the shelves 14. As a result, all or the major portion of the air in both of the air streams 36 and 38 is drawn into the duct means 34 and little, if any, of the chilled air spills over the lower front wall 10 of the case.

As shown in FIG. 1, the duct means 34 is preferably divided into two separate ducts or passages into which the parallel flowing air streams 36 and 38 may be directed. Thus, the duct means 34 may embody a refrigerated air return passage 40 having an inlet opening 42 through which the colder air stream 36 may be returned to the evaporator 22 and blower 26. In a similar way, the duct means 34 may embody a chilled air passage 44 having an inlet opening 46 through which air may flow to a blower 48. From the blower 48 the chilled air, which may be at a temperature of about 40° F., may be passed to a discharge flue 50 or to any other suitable location where the chilled air may be utilized or will not be objectionable.

As shown in FIG. 1, the inlet opening 42 of the refrigerated air return passage is located below and inward from the inlet opening 46 of the chilled air passage 44. This arrangement of the air inlet openings of the passages of the duct means 34 is preferred since the two streams of air 36 and 38 are generally parallel to each other and essentially laminar in character. However, the air inlet openings may be otherwise arranged and the division of the duct means 34 into two separate passages need not be effected until the laminar streams of air approach the lower portion of the duct means 34 adjacent the lower front wall 10 of the case.

Further, as shown in FIG. 1, the discharge flue 50, through which the chilled air is forced by the blower 48, may extend upwardly adjacent the rear wall 4 of the display case to an outlet opening 52 adjacent the hood 6 or the top of the display case. The chilled air is, thus, discharged upwardly toward the ceiling or upper portions of the store or area where the display case is located so that it will mingle with the warm air in the store and reduce the temperature thereof. In this way, the chilled ambient air, which would otherwise be spilled out of the case in an objectionable manner, could be used to reduce the load imposed on air conditioning equipment employed for cooling the air in the store or elsewhere.

In the alternative and as shown in FIG. 3, the chilled ambient air from passage 60 of the duct means may be directed to another display case or area to be chilled. Thus, the passage 60, through which the chilled air from duct means 34 is passed, may be directed to a case 62 which may be a vegetable stand, dairy case, candy display case or other unit which does not require such low refrigeration as does the case in which the evaporators 22 and 24 or other refrigerating means are located. In this way, the chilled ambient air from one case may be utilized to increase the efficiency of the system and extend the usefulness thereof to other equipment.

As further shown in FIG. 4, the chilled ambient air from a passage 72 communicating with the duct means 5 34 may be directed by a blower 71 to the condenser 73 of the refrigerating unit 75 in a “self contained” refrigerated display case so as to increase the efficiency thereof of the refrigerating unit by transfer of heat from the condenser to the air directed from the passage 72 to the 10 condenser 73 by the blower 71.

In the further alternative form of the invention illustrated in FIG. 5, the chilled ambient air received from the duct means 34 at the rear of the lower front wall 10 of the case is blown over heating elements 80 by a blower 15 82 and then is discharged through an outlet 84 near the bottom of the front wall 10 of the case. The air thus discharged has its temperature raised sufficiently to overcome any objection thereto whereby neither children nor adults will be chilled by the cooled ambient air.

In each of the forms of the invention described above, the air approaching the lower edge of the access opening 12 of the display case is drawn off in a manner to prevent spillage of cooled air from the case and loss of refrigeration thereby. In fact, if desired, the inlet open25 ing through which the chilled ambient air is drawn may be of such size or so located as to draw in unchilled ambient air for mixing with the chilled ambient air to temper or raise the temperature of the chilled ambient air until it is no longer objectionably cold when dis30 charged from the case.

The present invention obviously may be used in combination with various types of refrigerated equipment and with display cases maintained at temperatures above those usually employed in the preservation and display 35 of frozen foods, ice cream and the like. It should, therefore, be understood that the particular embodiments of the invention shown in the drawings and described above are intended to be illustrative only and are not intended to limit the scope of the invention.