Rethermalizing apparatus
Apparatus for and methods of rethermalizing a package of refrigerated or frozen food are disclosed. In general, heating mechanisms are brought into conductive heat transfer contact with the package of food and operated for a duration of rethermalization time to rethermalize the package of food by heating the food to a rethermalized temperature, and then, if desired, to hold the rethermalized package of food at a desired holding temperature for a duration of holding time. The rethermalization time can be relatively short (e.g., thirty minutes or less), and the holding time can range from a very short period of time to a very long period of time (e.g., four, six, eight or more hours) without significant loss of food quality. Other features of the apparatus and methods are disclosed.
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The present invention generally relates to food serving equipment and, more particularly, to apparatus for cooking of food or for reheating of pre-cooked food to be served.
BACKGROUND OF THE INVENTIONIn the fast-food industry, pre-cooked food is typically packaged in flexible material (e.g., plastic bags or film) and then frozen or refrigerated to be preserved until needed. To be prepared for consumption, the food must be heated or “rethermalized.” The food may then be held at a proper temperature until it is finally served.
Various techniques are used to rethermalize the food before it is served, such as by water bath, steam, convection with steam, forced convection, natural convection, infrared, conduction, and microwave. However, each of these techniques has certain drawbacks. In a water bath, for example, packages of frozen or refrigerated food are placed in a reservoir of heated water. This operation requires water supply lines, drain lines, input of substantial energy to heat the water and maintain it at a high temperature, venting of steam and water vapor from the reservoir, and regular cleaning of the reservoir. If a bag containing pre-cooked food breaks or leaks in the water bath, the water becomes contaminated and requires personnel to drain, refill, and reheat the water bath.
Two general disadvantages of existing rethermalization techniques are the inability to impart unique thermal treatment to separate bags of food, and the inability to accomplish even or uniform thermal treatment throughout the thickness of the food. In techniques such as water bath, steam, and various forms of convection, food bags are treated in a common chamber. Because the bags are not treated in individual compartments, they cannot be heated to different temperatures or at different rates. Rethermalization techniques such as infrared and microwave do not uniformly rethermalize food because infrared penetration depths vary significantly for various foods, and microwaves are not absorbed well by frozen food.
Another disadvantage of some existing rethermalization techniques, such as infrared, is that the pre-cooked food must be removed from its packaging and placed in a separate container before being re-heated. This process is inefficient and can reduce the amount of time the food can be held in a high-quality state prior to serving.
There is a need, therefore, for an improved process for rethermalizing food.
SUMMARY OF THE INVENTIONIn one embodiment, this invention is directed to a method of rethermalizing a package of refrigerated or frozen food and then holding the package of food at a selected holding temperature for a duration of holding time. The package of food comprises a portion of food contained in a flexible packaging material. The method comprises placing the package of food between opposing first and second heating mechanisms, moving the first heating mechanism toward the second heating mechanism to bring the heating mechanisms into conductive heat transfer contact with respective first and second surfaces of the package, and operating the first and second heating mechanisms in a rethermalizing mode for a duration of rethermalizing time during which the food is heated to a rethermalized temperature. After the food has reached the rethermalized temperature, the first and second heating mechanisms are operated in a holding mode while the heating mechanisms are in conductive heat transfer contact with the package to hold the food at a selected holding temperature for a duration of holding time. An electrical input/output device is operated to display information relating to the operation of the heating mechanisms in the rethermalizing and holding modes.
In another aspect, this invention is directed to apparatus for rethermalizing a package of refrigerated or frozen food and then holding the food in the package at a selected holding temperature for a duration of holding time. The package of food comprises a portion of food contained in a flexible packaging material. The apparatus comprises opposing first and second heating mechanisms. The first heating mechanism is movable toward the second heating mechanism to bring the heating mechanisms into conductive heat transfer contact with respective first and second surfaces of the package. The apparatus further comprises an electrical device for operating the first and second heating mechanisms. A tangible computer-readable storage medium has instructions for operating the first and second heating mechanisms in a rethermalizing mode for a duration of rethermalizing time during which the food is heated to a rethermalized temperature, and then in a holding mode while the heating mechanisms are in conductive heat transfer contact with the package to hold the food at a selected holding temperature for a duration of holding time. A controller is connected to the storage medium for executing the instructions and connected to the electrical device for controlling the electrical device. The apparatus also comprises an input/output device for inputting and displaying information relating to the operation of the heating mechanisms in the rethermalizing and holding modes.
In another aspect, this invention is directed to a method of rethermalizing a package of refrigerated or frozen food. The package of food comprises a portion of food contained in a flexible synthetic resin packaging material having a softening temperature. The method comprises placing the package of food between opposing first and second heating mechanisms, moving the first heating mechanism toward the second heating mechanism to bring the heating mechanisms into conductive heat transfer contact with respective first and second surfaces of the package, and operating the first and second heating mechanisms for a duration of rethermalizing time during which the food is heated to a rethermalized temperature. The duration of rethermalizing time comprises a first interval during which the first heating mechanism is heated to a first rethermalizing temperature greater than said softening temperature and a second interval following the first interval during which the first heating mechanism is heated to a second rethermalizing temperature less than said softening temperature but greater than said rethermalized temperature.
In another aspect, this invention is directed to apparatus for rethermalizing a package of refrigerated or frozen food. The package of food comprises a portion of food contained in a flexible synthetic resin packaging material having a softening temperature. The apparatus comprises opposing first and second heating mechanisms. The first heating mechanism is movable toward the second heating mechanism to bring the heating mechanisms into conductive heat transfer contact with respective first and second surfaces of the package. An electrical device operates the first and second heating mechanisms. A tangible computer-readable storage medium has instructions for operating the first and second heating mechanisms for a duration of rethermalizing time during which the food is heated to a rethermalized temperature. The duration of rethermalizing time comprises a first interval during which the first heating mechanism is heated to a first rethermalizing temperature greater than the softening temperature and a second interval following the first interval during which the first heating mechanism is heated to a second rethermalizing temperature less than the softening temperature but greater than the rethermalized temperature. The apparatus further comprises a controller connected to the storage medium for executing the instructions and connected to the electrical device for controlling the electrical device.
In another aspect, this invention is directed to a method of rethermalizing a package of refrigerated or frozen food. The package of food comprises a portion of food contained in a packaging material. The method comprises placing the package of food between opposing first and second heating mechanisms, moving the first heating mechanism toward the second heating mechanism to bring the heating mechanisms into conductive heat transfer contact with respective first and second surfaces of the package, and operating the first and second heating mechanisms for a duration of rethermalizing time during which the food is heated to a rethermalized temperature. The duration of rethermalizing time comprises a first interval during which the first heating mechanism is heated to a first rethermalizing temperature at least 20% greater than said rethermalized temperature, and a second interval following the first interval during which the first heating mechanism is heated to a second rethermalizing temperature less than said first rethermalizing temperature but greater than said rethermalized temperature.
In another aspect, this invention is directed to a method of rethermalizing food comprising placing a package of refrigerated or frozen food in a tray of thermally conductive material having a bottom wall, side walls and an open top, moving the modular unit into a compartment of a cabinet to a position in which the bottom wall of the modular unit is in conductive heat transfer contact with a lower heating mechanism in the compartment, and moving an upper heating mechanism in the compartment into conductive heat transfer contact with an outer upper face of the package in the open-top tray.
In another aspect, this invention is directed to apparatus for rethermalizing a package of frozen or refrigerated food. The apparatus comprises a frame including a bottom wall and two side walls partially defining a compartment for receiving the package. A heating mechanism defines an upper boundary of the compartment, and the heating mechanism is movable between a raised position and a lowered position to bring the heating mechanism into conductive heat transfer contact with the package. An actuating device on the frame is connected to the heating mechanism and operable to move the heating mechanism between the raised and lowered positions. A gasket between the side walls of the frame and the heating mechanism is in sealing contact with the side walls and the heating mechanism to isolate a space above the gasket from the compartment.
In another aspect, this invention is directed to apparatus for rethermalizing a package of frozen or refrigerated food. The apparatus comprises a frame including a bottom wall and two side walls partially defining a compartment for receiving the package. A heating mechanism defines an upper boundary of the compartment, and the heating mechanism is movable between a raised position and a lowered position to bring the heating mechanism into conductive heat transfer contact with the package. An actuating device on the frame is connected to the heating mechanism and operable to move the heating mechanism between the raised and lowered positions. The actuating device comprises a scissors mechanism that is expansible and contractible to move the heating mechanism between the raised and lowered positions.
In another aspect, this invention is directed to apparatus for rethermalizing a package of frozen or refrigerated food. The apparatus comprises a cabinet having at least one cavity therein and a heating module mounted within the cavity and being removable from the cavity. The heating module comprises a frame partially defining a compartment for receiving the package and a heating mechanism defining an upper boundary of the compartment. The heating mechanism is movable between a raised position and a lowered position to bring the heating mechanism into conductive heat transfer contact with the package.
In another aspect, this invention is directed to apparatus for rethermalizing a package of frozen or refrigerated food. The apparatus comprises at least three thermally conductive walls defining a cavity for receiving the package. The cavity has a width along an X-axis, a length along a Y-axis, and a height along a Z-axis. A first wall of the at least three walls is movable along a first axis of the X, Y and Z-axes, and a second wall of the at least three walls is movable along a second axis of the X, Y and Z-axes different from the first axis. The first and second walls are movable to bring the at least three walls into conductive heat transfer contact with an outside surface of the package. A heating system is provided for heating the at least three walls.
In another aspect, this invention is directed to apparatus for rethermalizing a package of frozen or refrigerated food which is adapted to change shape during rethermalization. The apparatus comprises a top wall, a bottom wall and at least one side wall defining a cavity for receiving the package. The walls are thermally conductive. The at least one side wall and either the top wall or the bottom wall are biased for movement toward the interior of the cavity for maintaining the three walls in conductive heat transfer contact with the outside surface of the package as the package changes shape during rethermalization.
In another aspect, this invention is directed to a method of rethermalizing food comprising placing a package of refrigerated or frozen food in a cavity of a modular unit, the cavity being defined by at least three thermally conductive walls. The method further comprises, manipulating the modular unit to bring the three walls into conductive heat transfer contact with an outside surface of the package, and heating the three walls to rethermalize the food in the package.
In another aspect, this invention is directed to apparatus for rethermalizing a package of frozen or refrigerated food. The apparatus comprises two opposing vertical side walls and a bottom wall. The side and bottom walls are of a thermally conductive material and define a cavity for receiving the package. An opening is provided for insertion of the package into the cavity. An actuating mechanism is operable for moving at least one of the side walls relative to the other of the side walls between a loading position in which the side walls are spaced sufficiently far apart for insertion of the package into the cavity through the opening, and a rethermalizing position in which the side walls are spaced closer together for conductive heat transfer contact with an outside surface of the package. A heating system is provided for heating the side and bottom walls.
Other objects and features will be in part apparent and in part pointed out hereinafter.
Corresponding reference characters indicate corresponding parts throughout the drawings.
DETAILED DESCRIPTIONReferring now to the drawings, and more particularly to
In the embodiment of
The heating system 15 in each compartment 7 comprises a first heating mechanism 41 adjacent the top of the compartment and a second heating mechanism 43 adjacent the bottom of the compartment. The first heating mechanism 41 comprises a rectangular frame 47 affixed to the structure of the cabinet 3, an upper heater plate 51 movable up and down in an opening 53 in the frame, and a heating element 55 comprising an electric coil on the upper surface of the heater plate 51 for heating the plate. The heater plate 51, preferably made of thermally conductive material, has an upstanding peripheral rim 59 having a telescoping fit in the frame opening 53. Flanges 63 extend laterally outward from the rim 59 and overlie an upwardly facing surface 65 of the frame. The arrangement is such that the heater plate 51 can move freely up and down relative to the frame 47. Downward movement of the heater plate 51 is limited by the contact of the flanges 63 with the upwardly facing frame surface 65. In this embodiment, the heater plate 51 is biased downward only by the force of gravity, but a suitable spring mechanism can be provided to add an additional downward bias.
The second heating mechanism 43 comprises a lower heater plate 71 affixed to the structure of the cabinet 3 and a heating element 75 comprising an electric coil on the lower surface of the heater plate for heating the plate. The lower heater plate is also preferably made of thermally conductive material and has a downward extending rim 77.
The upper and lower heater plates 51, 71 may have other configurations, including different shapes and sizes. Further, the heating surfaces of these plates may be irregular (e.g., dimpled or waffled) to increase the heat transfer area of the plates. The heating surfaces may also be coated or impregnated with a non-stick material so that the surfaces are easier to clean and are less prone to sticking to contents (e.g., a receptacle or bag of food) within the compartments, even when the heating surfaces are heated to high temperatures. Still further, the heating plates 51, 71 may be heated by means other than electric resistance heating elements, such as infrared heating, induction heating, or forced convection heating.
The apparatus includes a control system programmed for controlling the operation of the first and second heating mechanisms 41, 43 in each compartment 7. In one embodiment, the control system includes sensors (not shown) in the compartments 7 for sensing the temperatures of the upper and lower heater plates 51, 71, and a processor (not shown) programmed with suitable software for controlling the operation of the heating elements 55, 75 in response to signals from the sensors. Desirably, the processor is programmed for controlling the heating elements 55, 75 of the upper and lower heater plates 41, 43 independently. Further, the control system is desirably programmed to operate the heating mechanisms in one compartment 7 independent of the heating mechanisms in the other compartments. The advantages of these features will become apparent later. The control system includes an operator interface 81 (e.g., touch screen, key pad, or the like) on the cabinet. The interface 81 can include one or more input devices 83 associated with particular compartments for controlling temperature and/or time parameters of those compartments.
Optionally, suitable displays 85 (
Referring to
The interior surfaces of the tray 91 and cover 115 may be lined with a suitable layer or coating of non-stick material such as Teflon®.
When the cover 115 is closed, the top wall 117 of the cover overlies the bottom wall 95 of the tray 91 and the side wall 121 of the cover is spaced from the back wall 99b of the tray to define a cavity 131 for receiving a package 135 of food to be rethermalized. In particular, the package 135 comprises a portion of food contained in a flexible packaging material (e.g., plastic film) configured as a bag, wrapper or other envelope for holding the food. The cavity has a width 141 along the stated X-axis (
When the cover 115 is on the tray 91, the modular unit 11 has a Z-axis dimension which is somewhat greater than the Z-axis distance between the upper and lower heater plates 51, 71 in a compartment, at least when the upper heater plate is in its lowermost (gravity-biased) position. Thus, to facilitate loading of the modular unit 11 into the compartment 7, the front margin of the top wall 117 of the tray cover 115 is angled down to create a ramp 151 which is configured to engage the upper heater plate 51 and to raise it up as the modular unit is moved into a compartment of the cabinet (see
Referring to FIGS. 5 and 6A-6C, the tray cover 115 is biased in a rearward direction (along the Y-axis) relative to the tray 91 toward a closed position by a spring mechanism 161 comprising, in one embodiment, a biasing member 165 of inverted channel shape having a top wall 167 and front and back walls 169, 171 extending down from the top wall. The front wall 169 of the biasing member 165 is disposed outside of the tray 91 in a position forward of and generally parallel to the front wall 99a of the tray, and the back wall 171 of the biasing member is disposed inside the tray in a position rearward of and generally parallel to the front wall 99a of the tray. The biasing member is urged in a rearward direction by a pair of coil compression springs 175 mounted on pins 179. The pins are affixed to the back wall 171 of the biasing member 165 and slide in openings 181 in the front wall of the tray. The springs 175 are positioned between the front wall 99a of the tray 91 and the rear wall 171 of the biasing member 165 to urge the biasing member in a rearward direction along the Y-axis. When the tray cover 115 is mounted on the tray 91, the biasing member 165 is adapted to contact the front side wall 121 of the cover 115 and urge it in a rearward direction along the Y-axis toward the back wall of the tray 99b, i.e., toward a closed position of the cover, as shown in
Optionally, a latching device (not shown) may be provided on the tray 91 (e.g., on the front wall 99a of the tray) for holding the biasing member 165 in a retracted position against the bias of the springs 175 (
Other mechanisms can be used for spring biasing the front wall 121 of the cover toward the back wall 99b of the tray 91. In this regard, the term “spring” as used herein is intended to encompass any mechanism or force generated using one or more elastic members (e.g., coil springs, gas springs, elastic bands, etc.).
Desirably, the modular unit 11 is dimensioned such that respective walls 95, 99b, 99c, 99d, 117 and 121 of the unit are in conductive heat transfer contact with at least three (and preferably all six) faces of the outside surface of a package 135 placed in the unit. The package 135 may have any size and shape but is typically generally rectangular (e.g., 8.5 in. wide×12 in. long×1.75 in. high) such that its outside surface has what can be referred to as a top face, a bottom face, front and back faces extending in a generally X-direction, and two side faces extending in a generally Y-direction. During the rethermalization process, the contents of the package will change shape as it is heated and converts from a frozen or refrigerated (e.g., chilled or slacked) state to a more liquid or vaporous state. For maximum efficiency, it is desirable that conductive heat transfer contact be maintained between heated surfaces of the modular unit 11 and respective faces of the outside surface of the package. The modular unit achieves this result by maintaining contact between at least three heated walls of the unit and respective faces of the food package.
Desirably, the modular unit 11 has a Z-axis dimension 201 (
As used herein, “conductive heat transfer contact” means direct or indirect contact through which heat can be transferred by conduction. For example, as described above, the upper heater plate 51 is in direct (touching) contact with the cover 115. The package of food 135 is in indirect contact with the upper heater plate 51 through the cover 115, which is in direct (touching) contact with both the upper heater plate 51 and the package of food 135. The cover 115 and package of food 135 are both in conductive heat transfer contact with the heater plate 51. In various embodiments, heating mechanisms in direct contact or in indirect contact with a package of food 135 are considered to be in conductive heat transfer contact with the package of food.
Desirably, the tray 91 has an X-dimension which is substantially the same as the food package 135 in its frozen or refrigerated (e.g., chilled or slacked) state such that the two side walls 99c, 99d of the tray 91 maintain conductive heat transfer contact with respective side faces of the food package. The above-described operation of the modular unit to maintain conductive heat transfer contact is illustrated by comparison of, e.g.,
In another embodiment, the cover 115 and front wall 121 are not biased or movable in the Y-direction. In this embodiment, the front wall 121 and the back wall 99b of the tray define a Y-dimension which is substantially the same as the food package 135 in its frozen or refrigerated state such that the walls 121 and 99b maintain conductive heat transfer contact with respective side faces of the food package.
The modular units 11 are “modular” in the sense that they are constructed to have similar components. However, the units 11 may vary in size to accommodate food packages of substantially different size. Further, the compartments 7 may have different sizes to accommodate modular units of different sizes or to accommodate more than one unit in a single compartment. In the latter case, the two (upper and lower) heater plates 51, 71 in each compartment 7 should be sized to cover the top and bottom walls 95, 117 of adjacent modular units. Alternatively, separate sets of upper and lower heater plates can be provided for the modular units in the compartment.
In some instances, as where a package 135 contains air or other gas that may expand during heating, it may be desirable to vent the package before it is heated to a temperature which might otherwise cause it to rupture due to a build-up in pressure. To accomplish this, one or more projections can be provided on an interior surface of the tray cover 115, such as the lower surface of the top wall 117 of the cover, for piercing the package to allow venting of heated gas from the package.
In general, a method of using the apparatus involves placing a refrigerated (e.g., chilled or slacked) or frozen package 135 of food in the cavity 131 of a modular unit 11, manipulating the modular unit to bring at least three walls (e.g., 95, 117 and 121) into conductive heat transfer contact with an outside surface of the package, and heating the three walls to rethermalize the food in the package.
More specifically, a rethermalization process is started by removing the cover 91 of a modular unit 11 and, using the front wall 169 of the biasing member 165 as a handle, pulling the biasing member in a forward direction against the bias of the springs 175 to move the rear wall 171 of the biasing member toward a retracted position closer to the front wall 99a of the tray, as shown in
Once the food package 135 is loaded into the modular unit 11 as described above, the unit is moved into a compartment 7 of the cabinet 3 in the manner previously described. During this movement, the ramp 151 at the front of the cover 115 engages the upper heater plate 51 and raises it, thereby allowing the modular unit to be pushed into a rethermalizing position in which the upper heater plate 51 is in conductive heat transfer contact with the top wall 117 of the cover and the lower heater plate 71 is in conductive heat transfer contact with the bottom wall 95 of the tray 91. The operator then uses the operator interface 81 and/or the respective input device 83 to initiate a rethermalization operation.
After the rethermalization process is finished, the modular unit 11 is removed from the compartment 7 and the above steps are reversed to unload the rethermed package 135 from the unit. The contents of the package can be emptied into suitable holding equipment, such as a food serving unit of the type described in co-assigned application Ser. No. 11/250,778, filed Oct. 14, 2005, and published as Pub. No. US 2006/0081627on Apr. 20, 2006. Once unloaded, the modular unit 11 can be used again to rethermalize another food package.
The control system can be programmed to operate the heating mechanisms 41, 43 in each compartment 7 in various ways. By way of example but not limitation, the control system can be programmed to operate the upper and lower heater plates 51, 71 in each compartment independent of the heater plates in other compartments. This flexibility allows the food in each compartment to be heated to different temperatures and/or for different times, if desired. Further, the control system can be programmed to operate the upper and lower heater plates 51, 71 in each compartment 7 independently. For example, it may be desirable to heat the upper and lower plates to different temperatures depending on the amount of heat to be transferred by respective plates.
During the first interval 215, which is initiated by using the operator interface 81 and/or the respective input device 83, the control system operates the upper and lower heater plates 51, 71 in one or more compartments 7 at a predetermined temperature (or temperatures) to rethermalize the food in the compartment(s). During rethermalization, heater plate temperatures may range from 140 to 400 degrees F. (preferably below the softening temperature of the food packaging material if the packaging material is thermoplastic), and packaged food temperatures may range from 140 to 190 degrees F., although these ranges may vary. During this process, the temperatures of the heater plates 51, 71 are measured by the sensors, and the processor thermostatically controls the temperature of the heater plates by comparing signals from the sensors to predetermined set points. If the actual temperature of the heater plates is below the programmed set point, the appropriate heating element or elements 55, 75 are energized. If the actual temperature of the heater plates is above the programmed set point, the appropriate heating element or elements are not energized. During this retherm interval 215, the display 85 associated with each compartment 7 may indicate relevant information, such as the amount of retherm time remaining and the type of food in each compartment. A suitable alarm (visual and/or audible) may be activated by the control system to indicate the end of the rethermalization interval (e.g. upon expiration of a countdown clock).
After the retherm interval 215 has ended (i.e., timed out), the control system operates the upper and/or lower heater plates 51, 71 during the hold interval 217 to maintain the food in each compartment at a suitable and safe holding temperature, which may be a temperature the same as or different from the food rethermalization temperature (e.g., between 140 and 190 degrees F.). The food is held at this temperature while it remains in its packaging, thus preventing water evaporation and oxidation of the contents of the package. As a result, the quality of the food is maintained for a longer period of time. If the modular unit 11 containing the food is not removed by the end of the holding interval 217, the modular unit is removed for suitable disposal of the food. A suitable alarm (visual and/or audible) may be activated to indicate the end of the holding interval.
After the holding interval 217 has ended, as determined by the expiration of a predetermined interval of time or by input to the operator interface 81 and/or the respective input device 83 when an operator removes the modular unit 11 from the compartment 7, the control system operates the upper and/or lower heater plates 51, 71 to maintain them at an idle temperature in readiness for the start of another rethermalization event. The control operates the display 85 to indicate the idle/ready status of an empty compartment. Alternatively, the upper and/or lower heater plates 51, 71 may be de-energized after the holding interval 217 has ended and until initiation of another rethermalization event.
In the first experiment (
In the second experiment (
In the third experiment (
The results of the above experiments indicate that the heat transfer efficiency of the rethermalizing apparatus of this invention compares favorably to the heat transfer efficiencies achieved in a conventional water bath process but without the many drawbacks associated with using a water bath, as discussed above. This objective is achieved by bringing heated surfaces into conductive heat transfer contact with at least three faces of the outside surface of the packaging containing the food, and even more desirably with all six faces of the packaging. Further, the heated surfaces are biased inward toward the packaging so that they remain in contact with the packaging during the entire rethermalizing process, even as the food liquifies and the packaging changes shape during the process. As a result, the heat transfer efficiency is enhanced to an even greater degree.
Referring to
The apparatus 401 is used in much the same manner as apparatus 1. To initiate the process, the biasing member 165′ of modular unit 11′ is moved to its retracted position (
The modular unit 511 comprises a rectangular tray 527, a spring mechanism 531, and a U-shaped handle 535. The rectangular tray 527 has a bottom wall 541, four upstanding side walls 543a-543d (i.e., front and back walls 543a, 543b extending widthwise of the compartment in the X-direction and two side walls 543c, 543d extending lengthwise of the compartment in the Y-direction), and an open top. The tray 527 does not have a cover. Thus, the upper heater plate 505 makes direct contact with a top outer surface of a package of food (not shown) inserted in the tray 527.
The front wall 543a of the tray 527 extends in the X-direction beyond the edges of the side walls 543c, 543d, and in the Y-direction beyond the open top and the bottom wall 541 a distance sufficient to overlap the front face of the cabinet around the opening of a compartment into which the modular unit 511 is loaded. The extended front wall 543a acts to locate the tray 527 with respect to the upper heater plate 505 and the lower heater plate (not shown) when the modular unit is inserted into the compartment. Additionally, the front wall 543a closes the front opening of the compartment to reduce the loss of heat from the compartment. The front wall 543a may take shapes different than the rectangular one shown and may have a seal (not shown) around its inside perimeter for contact with the front face of the cabinet. Other means may be implemented to thermally insulate the compartment from the outside atmosphere, such as one or more doors on the cabinet (not shown).
The back wall 543b of the tray 527 is constructed to cooperate with the upper heater plate 505 to facilitate insertion of the modular unit 511 into the compartment. The upper margin of the back wall 543b is inclined to form a ramp 545. The ramp 545 cooperates with the tapered front rim portion 523 of the upper heater plate 505 to raise the upper heater plate as the modular unit 511 is moved into the compartment. Alternatively, only one of the back wall 543b and the front rim portion 523 may be constructed to facilitate insertion of the modular unit 511. The back wall 543b of the tray 527 has a height in the Z-direction less than the height of a package of food, whether in a frozen, refrigerated (e.g., chilled or slacked) or rethermalized state. Thus, when the modular unit 511 contains a package of food and is inserted into the compartment, the upper heater plate 505 rests against the upper outside surface of the package and at no time descends below the height of the back wall 543b. This enables the modular unit 511 to be pulled from the compartment without the upper heater plate 505 obstructing the back wall 543b. Alternatively, downward movement of heater plate 505 may be limited by the contact of the flanges 519 with the upwardly facing frame surface (not shown) such that the heater plate cannot descend below the height of the back wall 543b.
The spring mechanism 531 comprises a push plate (biasing member) 547, two pins 549, two coil compression springs (hidden behind front wall 543a), and a spring compression lever 553. The push plate 547 acts similarly to the back wall 171 of the biasing member 165 described above. The push plate 547 is disposed inside the tray 527 in a position rearward of and generally parallel to the front wall 543a of the tray. The push plate 547 is urged in a rearward direction by the compression springs mounted on pins 549. The pins 549 are affixed at one end to the push plate 547 and slide in openings in the front wall 543a. The springs are positioned between the front wall 543a and the push plate 547 to urge the push plate rearward in the Y-direction. The pins 549 are affixed at their other end to the lever 553. The lever 553 is mounted on the U-shaped handle 535, such that the lever slides in the Y-direction along the length of the legs of the handle. The configurations of the handle 535 and the lever 553 enable convenient and perhaps one-handed manipulation by an operator. Movement of the push plate 547 is preferably limited in the Y-direction (rearward) to preserve a gap between the lever 553 and the front wall 543a. The gap facilitates engagement of the lever 553 by an operator for moving the push plate 547 as needed during the process of loading and unloading a package of food into the modular unit 511, as described in more detail below. Accordingly, stops (not shown), such as rings affixed to the pins 549 or legs of the handle 535, or ridges along the sidewalls 543c, 543d or the bottom wall 541, may be positioned to limit movement of the push plate 547 in the rearward direction.
In use, the lever 553 is engaged to retract the push plate 547. A package of food may then be placed in the cavity 561 defined by the bottom wall 541 of the tray 527, the back wall 543b of the tray, the two side walls 543c, 543d of the tray, and the push plate 547. After the package is placed in the cavity 561, the lever 553 is released to allow the push plate 547 to urge the package into conductive heat transfer contact with respective walls of the tray 527 and the push plate. The modular unit 511 is then inserted into the compartment. As the modular unit 511 engages the compartment, the ramp 545 on the modular unit cooperates with the tapered front rim portion 523 of the upper heater plate 505 to raise the upper heater plate. The upper heater plate 505 rests in direct contact with the package of food once the modular unit is fully inserted in the compartment. After rethermalization is complete, the modular unit 511 is removed from the compartment, the push plate 547 is retracted using the lever 553, and the package of food is removed from the cavity 561.
The cabinet 703 shown in
The heating mechanisms 721, 725 may have different shapes or configurations without departing from the scope of the invention. For example, the first heating mechanism 721 may comprise a side wall and a bottom wall, and the second heating mechanism may comprise a side wall and a back wall. Additionally, both heating mechanisms 721, 725 may be movable, instead of only the second heating mechanism. Further, the bottom wall 729 and/or the back wall 731 may be movable independent of either side wall 727, 741.
An actuating mechanism, generally indicated 751, facilitates movement of the second heating mechanism and defines its path of movement within the compartment 707 between a loading or open position (
The four cranks 753a-753d of the actuating mechanism 751 are located generally adjacent the four corners of the second heating mechanism 725, the two cranks 753c, 753d at the rear of the mechanism being referred to as upper and lower rear cranks and the two cranks 753a, 753b at the front of the mechanism being referred to as upper and lower front cranks. The upper and lower rear cranks 753c, 753d have pivot (pin) connections 761 with ears 763 on the peripheral flange 733 of the first heating mechanism 721 toward the rear of the compartment 707, and the upper and lower front cranks 753a, 753b have pivot (pin) connections 767 with a suitable structure in the cabinet 703. The upper front and rear cranks 753a, 753c pivot about a first axis extending in the Y-direction, and the lower front and rear cranks 753b, 753d pivot about a second axis extending in the Y-direction spaced below the first axis. One arm of each of the front cranks 753a, 753b has a pivot (pin) connection with a pin 771 on the flange 745 of the second heating mechanism 725, and the other arm of each of the front cranks has a pivot (pin) connection 773 with one end of a respective bar 757a which extends generally parallel to and outboard of the flange of the heating mechanism at the front of the mechanism. Similarly, one arm of each of the rear cranks 753c, 753d has a pivot (pin) connection with a pin 771 on the flange 745 of the second heating mechanism 725, and the other arm of each of the rear cranks has a pivot (pin) connection 773 with one end of a respective bar 757b which extends generally parallel to and outboard of the flange of the heating mechanism at the rear of the mechanism. The arrangement is such that rotation of the cranks 753a-753d in one direction (clockwise in
The actuating mechanism 751 also comprises one or more biasing elements, shown as the tension coil spring 759 illustrated in
The actuating mechanism 751 further comprises an arm 781 and a handle 783 which may be used by an operator to move the first heating mechanism 725 along its defined path within the compartment 707. The arm 781 is rigidly affixed to the front face of the front bar 757a, and the handle 783 is affixed to the arm. Movement of the handle 783 generally from right to left in the X-direction (as viewed in
The actuating mechanism 751 as described above may have other forms without departing from the scope of the present invention. For example, the cranks 753a-753d may vary in number or shape. In addition, more or fewer springs 759 may be used, or biasing of one or more of the heating mechanisms 721, 725 may be accomplished in a different manner. Many constructions may be implemented to effectuate a movement of one or both of the heating mechanisms 721, 725 between open and closed positions.
Apparatus 701 also comprises a support mechanism generally indicated 787 for supporting a package of food 713 within the compartment 707, and more specifically within the cavity 752 for rethermalization. In the illustrated embodiment, the support mechanism 787 generally comprises an extensible and retractable arm 791 and a hanger 793 on the arm for supporting a package 713 in the cavity 752 between the first and second heating mechanisms 723, 725. The arm 791 is attached to a bracket 795 affixed to the flange 733 above the back wall 731 of the first heating mechanism 721 and extends as a cantilever generally horizontally from the bracket above the cavity 752. In the illustrated embodiment, the arm 791 comprises a plurality of telescoping sections so that the arm may be extended and retracted as needed during the package loading and unloading process to be described. The telescoping arm 791 has a grip 799 at its front end to facilitate movement of the arm by an operator between the retracted and extended positions shown in solid and phantom lines, respectively, in
To begin a rethermalizing operation, the telescoping arm 791 is moved from the retracted position shown in solid lines in
After the food package 713 is loaded into the cavity 752, the actuating mechanism 751 is used to move the second heating mechanism 725 from its open (loading) position (
After rethermalization is complete, the handle 783 is moved generally left to right (as viewed in
The apparatus 901 includes a control system (not shown) as described in previous embodiments for controlling operation of the heating system 909. The control system includes an operator interface 911 including one or more input devices 913 associated with one or more compartments 905 for controlling temperature and/or time parameters of individual compartments. An optional display 915 may be provided on the cabinet for displaying information relating to each compartment. A USB port 917 is provided on the front, lower right side of the cabinet for transferring information to the control system. The control system can be programmed to operate the heating systems 909 of the cabinet 903 in various ways, as described above, such as operating a heating system of one compartment 905 independently from the heating systems of other compartments. In the embodiment shown in
In this embodiment, the modular unit 907 comprises a receptacle in the form of a generally rectangular tray (also designated 907), which is preferably made of a thermally conductive material, such as aluminum. Alternatively, the modular unit 907 may be made of a plastic. The modular unit 907 does not include a cover as in other embodiments. The rectangular tray 907 has a bottom wall 921, four upstanding side walls 923a-923d (i.e., front and back walls 923a, 923b and two side walls 923c, 923d), a peripheral rim 925, and a U-shaped handle 927. Alternatively, the tray 907 may have no side walls 923a-923d. Desirably, however, the modular unit 907 is dimensioned such that respective walls 921 and 923a-923d are in conductive heat transfer contact with faces of the outside surface of the package 135 placed in the unit. Accordingly, the tray 907 has an X-dimension which is substantially the same as the food package 135 in its frozen or refrigerated state such that the two side walls 923c, 923d of the tray maintain conductive heat transfer contact with respective side faces of the food package. Similarly, the front wall 923a and the back wall 923b of the tray define a Y-dimension which is substantially the same as the food package 135 in its frozen or refrigerated state such that the front and back walls 923a, 923b maintain conductive heat transfer contact with respective side faces of the food package. For reasons which will become apparent, as best shown in
Alternatively, any of the modular units described in previous embodiments could be used. For example, modular units 11 or 11′ including a cover and/or a movable side wall could be used.
Although two compartments 905 are shown, cabinets 903 having one compartment or more than two compartments such as shown in
As shown in
As shown in
An example of a heating module 941 is shown in detail in
The frame 955 comprises lower and upper frame members 965, 967. The lower frame member 967 is formed as a channel having a bottom wall 969 and two side walls 971 extending up from the bottom wall. A heating element 973 (e.g., electric resistance coil) is provided below the bottom wall 969 of the lower frame member 965, which together comprise the lower heating mechanism 963. The lower frame member 965 is desirably made of a thermally conductive material, such as aluminum, and conductively heats the bottom wall 921 of the tray 907. By way of example, the bottom wall 969 of the lower frame member 965 may be a 3/16 in. thick plate of aluminum. Further, the heating element 973 may comprise an electric coil sandwiched between an upper layer of foil and a lower layer of foil, the latter of which is adhered to the lower surface of the wall 969 for increasing the conduction of heat to the plate.
Where the side walls 971 meet the bottom wall 969, the lower frame member 965 has steps 975 that extend along a length of the lower frame member. The steps 975 serve to guide the tray 907 as it is inserted into the compartment 905 to center the tray widthwise of the compartment for reasons which will become apparent. The steps 975 are sized such that the sides 923c, 923d of the tray 907 are relatively close to generally vertical side surfaces 975a of the steps. The side surfaces 975a of the steps 975 may touch the side walls 923c, 923d of the tray 907 such that the side walls of the tray may be conductively heated by the heating element 973 through the side surfaces of the steps. Flanges 977 are provided at upper ends of the side walls 971 for connecting the lower frame member to the upper frame member 967.
The upper frame member 967 is of inverted-channel shape and comprises a top wall 979 and two side walls 981 extending down from the top wall. Two flanges 983 extend along lower ends of respective side walls 981 for connecting the upper frame member 967 to the flanges 977 of the lower frame member 965. Lips 985 extend up from front and back edges of the top wall 979 for abutting against the front and back panels 933, 935 of the cabinet 903, respectively. An opening 987 in the top wall 979 provides clearance for the actuating device 959, as will become apparent. Upstanding flanges 989 and upstanding ears 991 along front and back edges of the opening 987 are provided for mounting components of the actuating device 959, as described in further detail below.
The upper heating mechanism 961 comprises a housing 993 disposed between the lower and upper frame members 965, 967. The housing 993 includes a rectangular frame 995 having four upstanding side walls (front wall 995a, back wall 995b, and side walls 995c, 995d) and an open top 997 and bottom 999. A plate 1001, which is desirably made of a thermally conductive material, such as aluminum, is mounted to the bottom of the frame 995, such as by bolts 1003 at corners of the frame. The plate 1001 closes the open bottom 999 of the frame 995 and forms a bottom wall, also designated 1001, of the housing 993. The bottom wall 1001 and side walls 995a-995d of the housing 993 define an interior space 1005. A heating element 1007 (e.g., electric coil) is housed in the interior space 1005 above the plate 1001. By way of example but not limitation, the heating element 1007 may comprises an electric coil sandwiched between an upper layer of foil and a lower layer of foil, the latter of which is adhered to the upper surface of the plate 1001 for increasing the conduction of heat to the plate. The plate 1001 itself may be a 3/16 in. thick aluminum plate.
As is now apparent, the compartments 905 in the cabinet 903 are bounded by the frame 955, the upper heating mechanism 961, and the front and back panels 933, 935 of the cabinet 903. More specifically, the bottom surface 929b of the compartment 905 comprises the bottom wall 969 of the lower frame member 965, and the opposite side surfaces 929e, 929f of the compartment comprise respective side walls 971, 981 of the upper and lower frame members 965, 967. The front and back surfaces 929c, 929d of the compartment 905 comprise the front and back panels 933, 935 of the cabinet 903, respectively. The upper heating mechanism 961 defines an upper boundary of the compartment. In particular, the upper surface 929a of the compartment 905 comprises the bottom wall 1001 of the upper heating mechanism 961. The housing 993 is movable within the frame 955 between a raised position (e.g.,
In some instances, as where the package 135 contains air or other gas that may expand during heating, it may be desirable to vent (e.g., puncture) the package before it is heated to a temperature which might otherwise cause it to rupture due to a build-up in pressure. In one embodiment, the tray 907 may have one or more puncture members (not shown) extending up from the tray, e.g., from one or more of the side walls 923c, 923d of the tray. Prior to placing the package in the tray, the package may be punctured using one or more of the puncture members. Other means may be used for puncturing the package to vent it. To minimize leakage from the package through the vent hole(s), it is preferable to puncture the top surface of the package.
When the package 135 is vented, vapor and/or other gases tend to escape the package and expand within the compartment 905. It is desirable to contain such vapor and/or other gases emitting from a package of food 135 (e.g., steak) within the compartment 905 to facilitate cleaning of the cabinet 903 and to protect against potential contamination (e.g., altered smell and/or taste) of a package of food (e.g., chicken) in another compartment. To assist in containing such vapor and/or other gases within the compartment 905, a gasket 1009 is mounted on the heating mechanism 961. The gasket 1009 comprises a rectangular piece of flexible air-impermeable material such as rubber having a rectangular opening approximately the same size and shape as the perimeter of the rectangular frame 995 of the housing 993. The gasket 1009 is held in place, for example, by multiple clamps 1011 that sandwich the gasket against an upward facing surface of a peripheral flange 1013 extending outward from the upper end of the frame 955 of the housing 993. In the illustrated embodiment, four clamps 1011 are used, one for each side of the housing 993. The clamps 1011 are secured to the housing 993 by bolts 1015 or other fasteners.
The gasket 1009 extends outward from all four side walls 995a-995d of the housing 993. The gasket 1009 is sized and shaped such that outer edges or margins 1017 of the gasket are in sealing contact with the front, back, and side surfaces 929c-929f of the compartment. “Sealing contact” as used herein means engagement of the gasket 1009 with respective surfaces 929c-929f of the compartment that prevents most vapor and/or other gases from passing between the gasket and respective side walls or surfaces. The gasket 1009 may be longer (X-direction and/or Y-direction) than the space between the heating mechanism 961 and respective compartment surfaces 929c-929f such that the gasket deforms (e.g., bends) when in contact with the surfaces. The gasket 1009 is movable with the heating mechanism 961 and “wipes” against the front, back and side surfaces 929c-929f of the compartment when the heating mechanism 961 is moved between its raised and lowered positions.
The gasket 1009 isolates a space 1019 above the gasket from the compartment 905 below the gasket. Thus, the gasket 1009 prevents most vapor and/or other gases from passing from the compartment 905 to the space 1019 above the heating mechanism 961. As a result, the gasket 1009 prevents most vapor and/or other gases from contacting components such as the actuating device 959 and the heating element 1007. Cleaning of the cabinet 903 is thus facilitated because residue or other waste generally forms within the compartment 905, where it may be reached by a user, not in the space 1019 above the gasket 1009.
Other suitable gaskets 1009 may be used to isolate the space 1019 above the gasket 1009 from the compartment 905. For example, gaskets comprising more than one piece of material or comprising different sizes or shapes may be used, such as a bellows gasket or a diaphragm gasket.
The actuating device 959 is operable to move the upper heating mechanism 961 between the raised position (e.g.,
In the illustrated embodiment, the actuating device 959 generally comprises a scissors mechanism 1021 that is extensible and contractible to raise and lower the upper heating mechanism 961. A shaft 1023 extending lengthwise of the heating module 941 is connected to the scissors mechanism 1021 by two mechanical links 1025. The shaft 1023 is rotatable by actuating a lever 1027 on a front end of the shaft to expand and contract the scissors mechanism 1021. Part of the scissors mechanism 1021 is housed in the interior space 1005 defined by the side walls 995a-995d and bottom plate 1001 of the housing 993. The actuating device 959 generally comprises front and back portions 959a, 959b, the front portion being generally a mirror image of the back portion about the plane A-A shown in
The scissors mechanism 1021 comprises first and second sets of longitudinal bars 1029a, 1029b. As viewed in
As viewed, for example, in
Right ends 1032b of the second bars 1032 have pivot (pin) connections 1041 with rollers 1043 disposed within guides 1045 mounted on the inside surfaces of the front and back walls 995a, 995b of the housing 993. Right ends 1031b of the first bars 1031 have pivot (pin) connections 1047 with rollers 1049 disposed within guides 1051 mounted on the upper frame member 967 between respective upstanding flanges 989 and ears 991. The guides 1045, 1051 comprise channels having an internal height (Z-direction) approximately the same as the diameter of the rollers 1043, 1049. The guides 1045, 1051 allow for movement of the rollers 1043, 1049 widthwise of the heating module 941 and thus movement of the pivot (pin) connections 1041, 1047 to the left and right in the X-direction.
The configuration of the scissors mechanism 1021 having pivot (pin) connections 1035, 1039 at left ends 1031a, 1032a of the first and second bars 1031, 1032 and pivot (pin) connections 1047, 1041 movable in the X-direction at right ends 1031b, 1032b of the first and second bars 1031, 1032 allows the scissors mechanism to expand and contract to move the upper heating mechanism 961 vertically (Z-direction) within the frame 955. Desirably, the pivot (pin) connections 1033, 1035, 1039, 1041, 1047 and rollers 1043, 1049 within the guides 1045, 1051 experience minimal friction to allow the upper heating mechanism to move from the raised position to the lowered position by the force of gravity only. As shown in
The shaft 1023 is connected to the scissors mechanism 1021 by the two mechanical links 1025 and is rotatable about a longitudinal axis B-B (
As viewed, for example, in FIGS. 41 and 43-45, rotation of the shaft 1023 in a clockwise direction expands the scissors mechanism 1021 to move the upper heating mechanism 961 to its lowered position (e.g.,
The mechanical links 1025 are configured to provide the actuating device 959 with an “over center” bias to hold the upper heating mechanism 961 in the raised position. As shown in
Desirably, the arrangement is such that minimal friction resists the movement of the heating mechanism 961 to its lowered position such that it freely moves to its lowered position (without manual actuation of the lever) after overcoming the “over center” bias. Thus, to move the upper heating mechanism 961 from the raised position (e.g.,
The actuating device 959 as described above may have other forms without departing from the scope of the present invention. Many constructions besides the illustrated actuating device 959 may be implemented to effectuate a movement of the upper heating mechanism 961 between the raised and lowered positions. For example, only one mechanical link 1025 may be used, and the mechanical links may vary in number or shape. As a further example, different components (e.g., up-down or push-pull) may be used in place of the rotatable shaft 1023 and mechanical links 1025 to expand and contract the scissors mechanism 1021.
The upper heating mechanism 961 is therefore movable downward into conductive heat transfer contact with the package of food 135 and maintains conductive heat transfer contact with the package during rethermalization as the package changes shape (e.g., decreases in height) during rethermalization (see
Features described above and additional features facilitate cleaning of the apparatus 901. For example, the distance provided between the upper heating mechanism 961 and the bottom surface 929b of the compartment 905 provides access (e.g., by a hand of a user) from the front or back of the cabinet 903 for cleaning the compartment 905. Further, the gasket 1009 isolates the space 1019 above the gasket from vapor and/or other gases generated within the compartment 905. Many non-heating surfaces are preferably made of stainless steel for ease of cleaning. Surfaces such as the internal surfaces of the compartment 929a-929f may be impregnated or coated with Teflon®. In addition, the heating modules 941 are removable from the cabinet 903, as described above, for maintenance procedures (e.g., cleaning) and replacement of defective parts.
The apparatus 901 is used in a similar fashion as embodiments described above. A tray 907 containing a package of food 135 is placed in the compartment 905. The upper heating mechanism 961 is then moved from its raised position (e.g.,
The various embodiments described above may have additional features. By way of example, the surface of the upper heating plate (e.g., plate 1001) contacting the upper surface of the package to be rethermalized may be coated so that it is less likely to stick to the packaging material, which may be a flexible sheet of synthetic resin material (e.g., a polymer film). One example of a suitable coating is a fluoropolymer coating sold under the trademark Excalibur® by Russel Products, Inc. Further, the upper surface of the wall (plate) 969 in contact with the bottom of the tray may be coated for wear, abrasion and corrosion resistance, as by hard anodizing. The heating elements 973, 1007 may be of any suitable type, such as Calrod heaters, rope heaters, silicone rubber mat heaters, etched-foil heaters, and cast-in heaters. The upper heating plate 1001 can also be heated by an infra-red energy source, which would have the advantage of eliminating electric wiring to the upper heating mechanism.
A USB port 1132 is provided for uploading and downloading information to and from the computer-readable storage medium 1104. Uploaded information may include, for example, different “retherm” programs for different foods. Downloaded information may include, for example, performance data. The USB port 1132 may be used in conjunction with a web-based programming system such as the system illustrated in
In one embodiment, the instructions to be loaded into the computer-readable storage medium 1104 for operating the first and second heating mechanisms 961, 963 during a rethermalization (“retherm”) cycle are developed empirically, i.e., by conducting tests to determine an appropriate sequence of time-and-temperature events for operating the heating mechanisms to achieve the desire result. The instructions will vary depending on various factors, such as the type of packaged food (e.g., beef, chicken, fish), the packaging material (e.g., thermoplastic synthetic resin material, thermoset synthetic resin material, metal foil material), package size, number of food packages to be placed in a compartment during a retherm cycle, desired duration of retherm time, desired duration of holding time, etc. For optimum results, a separate program or “recipe” of instructions for each type of food package to be rethermalized may be loaded into the computer-readable storage medium 1104.
The exemplary rethermalizing and holding temperatures stated in the immediately preceding paragraph are for a retherm and hold process for a food comprising a meat (beef) contained in packaging material of a thermoplastic synthetic resin material having a softening temperature of about 210 degrees F. These temperatures will vary depending on such factors as the type of food and packaging material (e.g., thermoplastic material, thermoset material, metal foil).
The first and second heating mechanisms 961, 963 may be operated at the same or different temperature levels during the retherm and holding cycles, depending on such factors as the conductivity of the surfaces of being heated, which may vary depending on the types of coatings on the surfaces. Also, the magnitude of the set points, and/or the number of set point changes, and/or the length of the time intervals between set point changes, may vary from one program to another. The temperatures to which the heating mechanisms 961, 963 are heated may differ depending on one or more factors such as the type of food in the package 135, the desired rethermalized temperature, the desired holding temperature, the type of packaging material, and other factors. In general, during the retherm cycle, the heating mechanisms 961, 963 are heated to a temperature selected to rethermalize the food as quickly as possible without significantly decreasing the quality of the food (e.g., scorching or burning meat or separating components of cream-based food) and without adversely altering (e.g., melting) the packaging material.
If a thermoplastic synthetic resin material is used as the packaging material, the softening and melting temperatures of the packaging material are significant factors in selecting the highest temperature to which the heating mechanisms should be heated. As used herein, the softening temperature ST means the temperature at which a thermoplastic packaging material becomes tacky or sticky to the touch. This temperature ST ranges from 140 to 225 degrees F. for many types of thermoplastic films used to package food. The melting temperature is a temperature greater than the softening temperature at which the thermoplastic packaging material transitions from a crystalline or semi-crystalline phase to a solid amorphous phase. For certain types of food (e.g., meat products) packaged in thermoplastic film, it has been found that the heating mechanisms 961, 963 can be operated at temperatures above the softening temperature of the packaging material but below its melting temperature, at least during an initial interval of the rethermalizing cycle. Operating the heating mechanisms at these relatively high temperatures has the advantage of driving as much heat as possible into the food without degrading it, thus reducing the amount of time required to complete the retherm process. For other types of food which degrade at lower temperatures, it may not be possible to operate the heating mechanisms above the softening temperature of the packaging material during any interval of the retherm process.
Thermoset synthetic resin materials and metal foil typically have very high melting temperatures. Therefore, if these types of materials are used as the packaging material, the critical factor is determining the maximum temperature at which the heating mechanisms 961, 963 should be operated is the temperature at which the food experiences a significant decrease in quality. This maximum temperature can be determined empirically and stated as a percentage of rethermalized temperature or a percentage of the holding temperature (which may or may not be the rethermalized temperature at the end of a retherm cycle). For example, for some types of food (e.g., beef, chicken, or steak), the heating mechanisms 961, 963 may be heated during the first time interval to a maximum temperature that is 20% higher than the rethermalized temperature or the holding temperature without substantially affecting the quality of the food. Other types of food (e.g., cheese or sauces) may be able to withstand temperatures of, for example, only 10 to 15 percent higher than the rethermalized temperature or the holding temperature without separating or degrading. In other embodiments, the heating mechanisms 961, 963 may be heated during the first time interval to a maximum temperature that is 25, 30, 35, 40, 45 or even 50 percent higher than the rethermalized temperature or the holding temperature without substantially affecting the quality of the food.
In the embodiment illustrated by the graph of
In one embodiment, the electrical device 1130 of the control system 1100 is an input/output device comprising a keyboard 1134 (
The electrical input/output device 1130 may have other configurations. For example, the input/output device 1130 may include a touchscreen.
An exemplary operation of the control system 1100 will now be described. When the power to the apparatus is turned on, the controller 1108 starts an initialization process during which the heating mechanisms 961, 963 remain de-energized, the keyboard display 1134 shows dashes, the controller 1108 checks for fault conditions, and the controller enters a “ready” mode. In the “ready” mode, the display 1146 associated with each compartment 905 displays certain information, including the “ready” status of the compartment, the number of food packages 135 (sometimes referred to as “bags”) in the compartment, and the name of the retherm program selected for the compartment. The status light 1140 remains off.
To begin a retherm cycle, one or more trays (e.g., tray 907), each containing one or more packages of food 135 to be rethermalized, are loaded into respective compartments 905. The arrow key 1142 corresponding to each compartment 905 containing food to be rethermalized is pressed to start a retherm cycle. During rethermalization, the controller 1108 controls the input/output device 1130 to illuminate the status light 1140 to a color (e.g., red) indicating a “retherm” status, and operates the display to display certain information relevant to the status of each compartment, such as the name of the retherm program selected for the compartment, the number of food packages or “bags” 135 in the compartment 905, and a decreasing count of time remaining in the programmed duration of retherm time, as provided by the timing device 1149. Optionally, the controller 1108 may operate the input/output device 1130 or an independent device to emit an audible or visual signal communicating the termination of the retherm cycle for the food in a particular compartment 905. The signal (e.g., audible alarm) may be discontinued, for example, by pressing the arrow key 1142 for that compartment 905, which causes the controller 1108 to enter a “holding” mode. If the arrow key 1142 for a compartment 905 is pressed during the retherm cycle, the program for that compartment 905 is cancelled and the controller 1108 returns to the “ready” mode.
When a holding cycle is initiated, the status light 1140 for that compartment changes color (e.g., to green), and the display 1146 for that compartment displays certain information, such as the name of the retherm program selected for the compartment, the number of food packages or “bags” 135 in the compartment, and an increasing count of time so that an operator can determine how long the food in the compartment has been in a holding mode. Optionally, the controller 1108 may operate the input/output device 1130 or an independent device to emit an audible or visual signal that signals the end of a maximum duration of holding time for the food still in a compartment 905, so that any food remaining in the compartment may be removed for disposal (e.g., discarded). The arrow key 1142 for a compartment 905 may be pressed during the holding cycle to return the compartment to the “ready” mode.
The keyboard 1134 associated with each compartment 905 can also be used to select the appropriate retherm program to be used, and to select the number of packages 135 to be placed in a compartment for rethermalization (e.g., one bag, two bags, three bags, four bags, etc.) The selection process may be carried out by manipulating the different elements on the keyboard 134 (e.g., the arrow and enter keys), as will be understood by those skilled in the programming art. Further information regarding this process and the control system 1100 generally is contained in attached Appendix A incorporated as part of this specification.
In the illustrated embodiment, the input/output device 1130 is used both to input and to display information relevant to the operational status of each compartment 905, such as the mode of operation, the amount of time elapsed or remaining in a particular mode, and the end of a particular mode. Alternatively, a separate device having no input function can be provided for outputting (e.g., displaying) information relevant to the operational status of each compartment.
Having described the above embodiments of the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. For example, the heating mechanisms 41, 43 can take other forms. Further, one or both heater plates 51, 71 can be guided for movement by suitable guide mechanisms. Similarly, the modular units described above can take other forms.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. For example, the apparatus 1 described above provides for the efficient transfer of heat to the food being rethermalized, without many of the problems associated with conventional rethermalization techniques, such as water bath and steam methods. Further, the thermal treatment for each item of packaged food can be tailored according to need or desire. Also, by rethermalizing the food while it is contained in unopened packaging, evaporation of water from the food and oxidation of the food is prevented for increasing the amount of holding time the food can be maintained in a state of high quality. Still further, the apparatus and methods of this invention can be used to rethermalize both frozen foods and “slacked” food, i.e., food which is chilled but not frozen. Thus there is no need to “slack” frozen food prior to beginning the retherm process. Nor is there any need to transfer the rethermalized food to a separate holding container prior to serving. The rethermed packaged food can simply be maintained in the modular unit until it is ready to be served.
When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
Claims
1. A method of rethermalizing a package of refrigerated or frozen food and then holding the package of food at a selected holding temperature for a duration of holding time, said package of food comprising a portion of food contained in a flexible packaging material, the method comprising
- placing said package of food between opposing first and second heating mechanisms,
- moving the first heating mechanism toward the second heating mechanism to bring the bringing opposing first and second heating mechanisms into conductive heat transfer contact with respective first and second opposite surfaces of the package when the package is between the first and second heating mechanisms, and
- operating the first and second heating mechanisms in a rethermalizing mode for a duration of rethermalizing time during which the food is heated to a rethermalized temperature,
- after the food has reached said rethermalized temperature, operating the first and second heating mechanisms in a holding mode while the heating mechanisms are in conductive heat transfer contact with said first and second opposite surfaces of the package to hold the food at a selected holding temperature for a duration of holding time, and
- operating an electrical input/output device to display information relating to the operation of the heating mechanisms in said rethermalizing and holding modes.
2. The method of claim 1, wherein said displayed information comprises a decreasing count of time remaining in said duration of rethermalizing time and an increasing count of time in said duration of holding time.
3. The method of claim 1, further comprising audibly or visually signaling the end of said duration of rethermalizing time.
4. The method of claim 3, further comprising audibly or visually signaling the end of said duration of holding time.
5. The method of claim 1, further comprising operating at least one of the first and second heating mechanisms during an interval of said rethermalizing mode at a temperature above a softening temperature of said flexible packaging material.
6. The method of claim 1, further comprising operating at least one of the first and second heating mechanisms during an interval of said rethermalizing mode at a temperature at least 20% higher than said holding temperature.
7. Apparatus for rethermalizing a package of refrigerated or frozen food and then holding the food in the package at a selected holding temperature for a duration of holding time, said package of food comprising a portion of food contained in a flexible packaging material, the apparatus comprising
- opposing first and second heating mechanisms, the first heating mechanism being movable toward the second heating mechanism to bring the heating mechanisms into configured for conductive heat transfer contact with respective first and second opposite surfaces of the package when the package is between the first and second heating mechanisms,
- an electrical device for operating the first and second heating mechanisms,
- a tangible computer-readable storage medium having instructions for operating the first and second heating mechanisms in a rethermalizing mode for a duration of rethermalizing time during which the food is heated to a rethermalized temperature, and then in a holding mode while the heating mechanisms are in conductive heat transfer contact with said first and second opposite surfaces of the package to hold the food at a selected holding temperature for a duration of holding time,
- a controller connected to said storage medium for executing the instructions and connected to the electrical device for controlling the electrical device, and
- an input/output device for inputting and displaying information relating to the operation of the heating mechanisms in said rethermalizing and holding modes.
8. The apparatus of claim 7, wherein said input/output device comprises a display device that displays a decreasing count of time remaining in said duration of rethermalizing time and an increasing count of time in said duration of holding time.
9. The apparatus of claim 7, wherein said input/output device comprises an audible or visual signal that signals the end of said duration of rethermalizing time.
10. The apparatus of claim 9, wherein said input/output device comprises an audible or visual signal that signals the end of said duration of holding time.
11. The apparatus of claim 7, wherein the tangible computer-readable storage medium has instructions for operating the first and second heating mechanisms for an interval during said rethermalizing mode at a temperature above a softening temperature of said flexible packaging material.
12. A method of rethermalizing a package of refrigerated or frozen food, said package of food comprising a portion of food contained in a flexible synthetic resin packaging material having a softening temperature, the method comprising
- placing said package of food between opposing first and second heating mechanisms,
- moving the first heating mechanism toward the second heating mechanism to bring the bringing opposing first and second heating mechanisms into conductive heat transfer contact with respective first and second surfaces of the package when the package is between the first and second heating mechanisms, and
- operating the first and second heating mechanisms for a duration of rethermalizing time during which the food is heated to a rethermalized temperature,
- said duration of rethermalizing time comprising a first interval during which the first heating mechanism is heated to a first rethermalizing temperature greater than said softening temperature and a second interval following the first interval during which the first heating mechanism is heated to a second rethermalizing temperature less than said softening temperature but greater than said rethermalized temperature.
13. The method of claim 12, further comprising continuing to operate the first and second heating mechanisms after the food in the package has reached said rethermalized temperature to hold the food in the package at a selected holding temperature for a duration of holding time.
14. The method of claim 12, wherein said first rethermalizing temperature is at least 10 degrees F. greater than said softening temperature.
15. Apparatus for rethermalizing a package of refrigerated or frozen food, said package of food comprising a portion of food contained in a flexible synthetic resin packaging material having a softening temperature, said apparatus comprising
- opposing first and second heating mechanisms, the first heating mechanism being movable toward the second heating mechanism to bring the heating mechanisms into configured for conductive heat transfer contact with respective first and second surfaces of the package when the package is between the first and second heating mechanisms,
- an electrical device for operating the first and second heating mechanisms,
- a tangible computer-readable storage medium having instructions for operating the first and second heating mechanisms for a duration of rethermalizing time during which the food is heated to a rethermalized temperature,
- said duration of rethermalizing time comprising a first interval during which the first heating mechanism is heated to a first rethermalizing temperature greater than said softening temperature and a second interval following the first interval during which the first heating mechanism is heated to a second rethermalizing temperature less than said softening temperature but greater than said rethermalized temperature, and
- a controller connected to said storage medium for executing the instructions and connected to the electrical device for controlling the electrical device.
16. The apparatus of claim 15, wherein said instructions further comprise operating the first and second heating mechanisms to hold the food in the package at a selected holding temperature for a duration of holding time after the food in the package has reached said rethermalized temperature.
17. The apparatus of claim 15, wherein said first rethermalizing temperature is at least 10 degrees F. greater than said softening temperature.
18. A method of rethermalizing a package of refrigerated or frozen food, said package of food comprising a portion of food contained in a packaging material, the method comprising
- placing said package of food between opposing first and second heating mechanisms,
- moving the first heating mechanism toward the second heating mechanism to bring the bringing opposing first and second heating mechanisms into conductive heat transfer contact with respective first and second surfaces of the package when the package is between the first and second heating mechanisms, and
- operating the first and second heating mechanisms for a duration of rethermalizing time during which the food is heated to a rethermalized temperature,
- said duration of rethermalizing time comprising a first interval during which the first heating mechanism is heated to a first rethermalizing temperature at least 20% greater than said rethermalized temperature, and a second interval following the first interval during which the first heating mechanism is heated to a second rethermalizing temperature less than said first rethermalizing temperature but greater than said rethermalized temperature.
19. The method of claim 18, wherein said packaging material is a thermoplastic synthetic resin material.
20. The method of claim 18, wherein said packaging material is a thermoset synthetic resin material.
21. The method of claim 18, wherein said packaging material is a metal foil.
22. The method of claim 1 wherein bringing the opposing first and second heating mechanisms into conductive heat transfer contact with the respective first and second opposite surfaces of the package comprises moving the first heating mechanism toward the second heating mechanism.
23. The method of claim 1 wherein bringing the opposing first and second heating mechanisms into conductive heat transfer contact with the respective first and second opposite surfaces of the package comprises moving the first heating mechanism away from the second heating mechanism.
24. The method of claim 1 wherein bringing the opposing first and second heating mechanisms into conductive heat transfer contact with the respective first and second opposite surfaces of the package comprises placing said package between said opposing first and second heating mechanisms in a compartment bounded by at least an upper surface and a bottom surface, and wherein said package is in the compartment while operating the first and second heating mechanisms in said rethermalizing mode and while operating the first and second heating mechanisms in said holding mode.
25. The apparatus of claim 7 wherein the first heating mechanism is movable toward the second heating mechanism for bringing the first and second heating mechanisms into conductive heat transfer contact with the respective first and second opposite surfaces of the package.
26. The apparatus of claim 7 wherein the first heating mechanism is movable away from the second heating mechanism for bringing the first and second heating mechanisms into conductive heat transfer contact with the respective first and second opposite surfaces of the package.
27. The apparatus of claim 7 wherein said opposing first and second heating mechanisms are in a compartment bounded by at least an upper surface and a bottom surface, and wherein the tangible computer-readable storage medium has instructions for operating the first and second heating mechanisms in said rethermalizing mode and said holding mode while the package of food is in the compartment.
28. The method of claim 12 wherein bringing the opposing first and second heating mechanisms into conductive heat transfer contact with the respective first and second surfaces of the package comprises moving one of the first and second heating mechanisms toward the other of the first and second heating mechanisms.
29. The method of claim 12 wherein bringing the opposing first and second heating mechanisms into conductive heat transfer contact with the respective first and second surfaces of the package comprises moving one of the first and second heating mechanisms away from the other of the first and second heating mechanisms.
30. The apparatus of claim 15 wherein one of the first and second heating mechanisms is movable toward the other of the first and second heating mechanisms for bringing the first and second heating mechanisms into conductive heat transfer contact with the respective first and second surfaces of the package.
31. The apparatus of claim 15 wherein one of the first and second heating mechanisms is movable away from the other of the first and second heating mechanisms for bringing the first and second heating mechanisms into conductive heat transfer contact with the respective first and second surfaces of the package.
32. The method of claim 18 wherein bringing the opposing first and second heating mechanisms into conductive heat transfer contact with the respective first and second surfaces of the package comprises moving one of the first and second heating mechanisms toward the other of the first and second heating mechanisms.
33. The method of claim 18 wherein bringing the opposing first and second heating mechanisms into conductive heat transfer contact with the respective first and second surfaces of the package comprises moving one of the first and second heating mechanisms away from the other of the first and second heating mechanisms.
34. The apparatus of claim 15 in combination with the package of refrigerated or frozen food comprising the portion of food contained in the flexible synthetic resin packaging material having the softening temperature, the package being between and in conductive heat transfer contact with the first and second heating mechanisms for rethermalizing the portion of food during said first and second rethermalizing intervals.
35. The apparatus of claim 7 wherein the tangible computer-readable storage medium has instructions for operating at least one of the first and second heating mechanisms for an interval during said rethermalizing mode at a temperature at least 20% higher than said holding temperature.
36. The apparatus of claim 35 wherein the tangible computer-readable storage medium has instructions for operating at least one of first and second heating mechanisms for the interval during said rethermalizing mode at a temperature in a range of 215-400 degrees F.
37. The method of claim 5 wherein operating at least one of the first and second heating mechanisms during the interval of said rethermalizing mode at the temperature above the softening temperature of said flexible packaging material comprises operating at least one of the first and second heating mechanisms during said interval at a temperature in a range of 215-400 degrees F.
38. The method of claim 6 wherein operating at least one of the first and second heating mechanisms during the interval of said rethermalizing mode at the temperature at least 20% higher than said holding temperature comprises operating at least one of the first and second heating mechanisms during said interval at a temperature in a range of 215-400 degrees F.
39. The apparatus of claim 11 wherein the tangible computer-readable storage medium has instructions for operating the first and second heating mechanisms for the interval during said rethermalizing mode at a temperature in a range of 215-400 degrees F.
40. The method of claim 12 wherein said first rethermalizing temperature is in a range of 215-400 degrees F.
41. The apparatus of claim 15 wherein said first rethermalizing temperature is in a range of 215-400 degrees F.
42. The method of claim 18 wherein said first rethermalizing temperature is in a range of 215-400 degrees F.
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Type: Grant
Filed: Sep 4, 2014
Date of Patent: Nov 3, 2015
Assignee: Duke Manufacturing Co. (St. Louis, MO)
Inventors: Steven M. Shei (Fort Wayne, IN), Scott E. Willis (Sedalia, MO)
Primary Examiner: William Doerrler
Application Number: 14/477,488
International Classification: H05B 3/02 (20060101); A21B 3/00 (20060101); A47J 39/02 (20060101); F24C 15/00 (20060101); A47J 27/00 (20060101);