Horizontal Refrigerator

This invention relates to self-contained countertop refrigeration units with a raised pan rail and in particular to an improved arrangement for maintaining a low temperature in a food pan mounted in the rail.

A self-contained food countertop refrigeration unit includes a thermally insulated stainless steel walled cabinet having a refrigerated product containing chamber and a refrigerated upwardly open compartment known as a "pan rail" for receiving one or more pans useful in dispensing food. The pans are refrigerated first by a fan forcing refrigerated air upwardly from a bottom food storage chamber of the cabinet so as to be circulated around the bottom and sides of the pans and second by thermal conduction between a series of refrigeration coils, compartment walls and sidewalls of the pan. As shown in FIG. 1, the refrigeration coils are bonded behind and to the interior walls and bottom wall of the pan rail and the food pan is mounted on the rail so as to be flush with the top horizontal surface of the cabinet. This dual mode arrangement of maintaining the food pan cool has been found to be satisfactory under existing food industry standards set by the National Sanitation Foundation (NSF) which require that the unit simultaneously maintain the temperature of food in the pan at 45.degree. F. for prolonged periods with minimum dehydration and the storage chamber at 40.degree. F. with a maximum compressor runtime of 70 percent in a 100.degree. F. ambient.

NSF has recently changed the approved standard to a maximum product temperature of 40.degree. F. which can occur in a warm environment such as found in a pizza restaurant. This concern has led to the establishment of a new standard that a refrigerated food preparation table be capable of taking a food product at 38.degree. and maintaining it for a period of four hours between 33.degree. F. and 40.degree. F. in a room wherein the ambient temperature is 100.degree. F. The above-mentioned food preparation table cannot always keep up with the product heat gain in such environment.

The primary object of this invention is provision of a horizontal self-contained counter-top height upwardly open food preparation table which achieves the above requirements as to control of temperature in a food pan.

In accordance with this invention there is provided a food preparation table including a refrigerator cabinet having a partition dividing the cabinet into a lower cooling chamber and an upper cooling chamber, a refrigeration system including refrigerant carrying coils operatively connected to a compressor, a condenser and an evaporator to refrigerate the cooling chambers. The upper cooling chamber comprises an elongated horizontal open top receptacle including elongated spaced front and back sidewalls, integral spaced endwalls, and an integral bottom floor defined by the partition. The front and back sidewalls each have, respectively, a horizontal ledge between upper and lower sidewall portions whereby to define a recessed rail for supporting the top rim of the pan between the top surface of the table and the bottom floor, and a lower interior space in the receptacle for receiving the body of the pan. Refrigerant coils adjacent the upper sidewall portions and uniquely located reduce the temperature of the air in the upper interior space of the receptacle to a temperature below ambient to assure that a cool thermal blanket extends across the top surface of the food pan to inhibit dehydration of the food. Refrigerant passing through the coils adjacent the lower sidewall portions conduct through the pan walls to maintain the food temperature at the desired level.

Advantageously, the recessed pan rail allows the unit to take advantage of the phenomena that hot dehydrating air above the receptacle will tend to rise and the denser cooling air will cling in the recess to the top of the food.

Further, the recessed pan eliminates the need for an air circulating fan and refrigeration relies entirely on refrigerant passed through evaporator coils.

The foregoing and other objects and advantages will become more apparent when viewed in light of the accompanying drawings and following detailed description of the invention in which:

FIG. 1 is a section view of a prior art pan rail;

FIG. 2 is a perspective view of a self-contained food preparation table;

FIG. 3 is a section view taken along line 3--3 of the food preparation table of FIG. 2 showing a pan rail according to the present invention; and

FIG. 4 is a detailed section view of the pan rail taken along line 4--4 of FIG. 3.

Turning now to the drawings, FIGS. 2-4 show a horizontal self-contained countertop height refrigerator table 10 which comprises an elongated generally rectangular base defining a cabinet 12 having a refrigerated chamber 14 for storing foods, and a pair of doors 16 for closing the chamber, and a pair of elongated upwardly open receptacles or compartments 18 for receiving food pans 20 useful in storing food to be dispensed and coverable by respective lids 22. A refrigeration system (not shown) includes a compressor and a condenser supported adjacent the base cabinet, an evaporator cabinet 24 supported adjacent the refrigeration system and having an evaporator (not shown), and copper tubing 26 for connecting the flow of refrigerant between the compressor, the condenser and the evaporator. Base cabinet 12 has thermally insulated wall preferably formed of spaced sheets of stainless steel and the area between the sheets being filled with a suitable thermally insulative material 13, such as polyurethane, foamed in place and about the refrigerant tubing.

Receptacle 18 is elongated generally horizontally extending, and includes elongated spaced front and back sidewalls 28 and 30, integral spaced endwalls 32 and 34, and an integral bottom floor 36 defining an interior space in the receptacle. Each of the respective sidewalls includes a horizontal ledge 36 and 38 between the open top surface 40 and bottom floor, the ledges dividing the respective sidewalls into a first wall portion 28a and 30a adjacent the open top, and a second wall portion 28b and 30b adjacent the bottom floor. The ledges are adapted to define a horizontal rail for supporting the rims 21 of one or more food pans 20 in lateral side-by-side relation and at a location vertically below horizontal surface 40. Preferably, the sidewalls 28 and 30 are at an angle of between 10 to 15 relative to a vertical and preferably at about 13.degree. F., and bottom floor 36 is at an angle of about 8.degree. to a horizontal, and acts to enable fluids to drain outwardly from the bottom of receptacle 18.

Further, the refrigerant tubing 26 encircles the receptacle. As shown in FIGS. 3 and 4, the tubing associates two vertically separated coils, respectively, with the upper wall portions 28a and 30a, and four vertically separated coils, respectively, with the lower wall portions 28b and 30b. To enhance thermal conduction, the coils are intimately connected to the inner surface of the stainless steel sheet of each respective sidewall. As shown in FIG. 4, aluminum duct tape 42 can be utilized both to prevent foam 13 from becoming lodged between the copper tube where it makes a line contact with the stainless steel wall and to increase the area of the thermal conductive path.

The coils associated with the lower wall portions 28b and 30b operate to complete a thermal path between the refrigerant, the tubing 26, the sidewalls of the pan 20 and the refrigerator and act to maintain the food temperature at a preset temperature. The coils associated with the upper wall portions 28a and 30a operate to chill the air in the upper portion of the receptacle 18 whereby due to the fact that the cool air is more dense than warm air, will tend to form a thermal blanket or barrier of cold air across the top of the pan and the food therein, thereby inhibiting dehydration which could be caused by the warmer ambient air.

An arrangement for defrosting the cooling coils includes a sensor (not shown) which will operate at preset intervals to bleed hot gas into the compressor, whereby to inhibit ice build-up on the coils. An automatic hot gas defrost system prevents ice build-up which would otherwise lower optimum performance of the table.

Thus, there is disclosed in the above-description and in the drawings and embodiment of the invention which fully and effectively accomplishes the objects thereof. However, it will be apparent that variations in the details of the apparatus may be indulged in without departing from the invention herein described, or the scope of the appended claims.