1. Field of the Invention
This application relates generally to a method and apparatus for storing a food item and, more specifically, to a refrigeration device and method exposes food stored in a refrigerated environment to a field generated using a low-frequency alternating signal.
2. Description of Related Art
Food can be stored for lengthy periods of time in refrigerated environments below 0° C. But the freshness and overall quality of the food can deteriorate as a result of being exposed to freezing temperatures. For instance, the food can show signs of an undesirable condition such as freezer burn. As another example, frozen foods typically need to be defrosted from a frozen state before being cooked or served. Defrosting within a conventional refrigerated environment with a temperature above freezing such as the fresh-food compartment is time consuming. Defrosting frozen foods on a countertop or other non-refrigerated environment for prolonged periods of time is not advisable because the temperature of exposed portions of the food may rise above safe storage temperatures in the time required for internal portions of the food to thaw. And using a cooking appliance such as a microwave to speed the thawing process can prematurely cook some portions of the food while leaving other portions frozen.
In an effort to at least partially combat such problems, and possibly other problems not mentioned above, stored foods have been exposed to an electrostatic field within such refrigerated environments to prolong the length of time that food can be stored before experiencing freezer burn. One example of such a system involves a conductor placed in a dedicated freezer as a shelf on which food is to be placed. With the food in place, an electric signal is introduced to the conductor to generate the field. However, generating a field within a dedicated freezer is of limited usefulness. The temperature within the entire freezer compartment must be maintained at a suitable temperature for the specific food being stored, making such an appliance impractical for storing a variety of different types of food at different temperatures.
Other systems utilizing fields for food preservation have attempted to maximize storage space within a refrigerated compartment by embedding conductors in opposite lateral side walls defining the compartment. But spacing the conductors so far apart has called for generation of the field using high-frequency driving signals, possibly upwards of 500 kHz. Such high-frequency systems require complex drive circuitry that can add to the cost of such systems and have an impact on the energy efficiency of those systems.
Accordingly, there is a need in the art for a refrigeration device with a plurality of different refrigerated compartments to accommodate a variety of food storage needs, and a field is generated in at least one of the compartments using a low-frequency driving signal.
According to one aspect, the subject application involves a refrigeration device for storing food within an electric field. The refrigeration device includes a fresh food compartment in which food is to be stored within a refrigerated environment having a target temperature above zero degrees Centigrade, and a freezer compartment in which food is to be stored in a sub-freezing environment having a target temperature below zero degrees Centigrade. A storage compartment in which a desired temperature for storing food in the storage compartment is selectable by a user independently of the target temperature of at least one of the fresh food compartment and the freezer compartment is also provided. A refrigeration system provides a cooling effect to the fresh food compartment, the freezer compartment and the storage compartment, and a conductor is arranged within close physical proximity to a bottom surface of the storage compartment. A control system controls delivery of an alternating electric signal to the conductor for generating an electric field that extends into the storage compartment, wherein the alternating electric signal comprises a frequency less than 1 kHz and a voltage greater than or equal to 1 kV.
The above summary presents a simplified summary in order to provide a basic understanding of some aspects of the systems and/or methods discussed herein. This summary is not an extensive overview of the systems and/or methods discussed herein. It is not intended to identify key/critical elements or to delineate the scope of such systems and/or methods. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
The invention may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein:
Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention. Relative language used herein is best understood with reference to the drawings, in which like numerals are used to identify like or similar items. Further, in the drawings, certain features may be shown in somewhat schematic form.
It is also to be noted that the phrase “at least one of”, if used herein, followed by a plurality of members herein means one of the members, or a combination of more than one of the members. For example, the phrase “at least one of a first widget and a second widget” means in the present application: the first widget, the second widget, or the first widget and the second widget. Likewise, “at least one of a first widget, a second widget and a third widget” means in the present application: the first widget, the second widget, the third widget, the first widget and the second widget, the first widget and the third widget, the second widget and the third widget, or the first widget and the second widget and the third widget.
To restrict access to an interior of the fresh food compartment 12, a first door 22 is pivotally connected to the cabinet 12 adjacent to a first lateral side of the cabinet 12 with a hinge assembly. Likewise, a second door 26 is pivotally connected to the cabinet 12 adjacent to a second lateral side to the cabinet 12 with a hinge assembly. The first and second doors 22, 26 are each insulated to minimize the escape of heat from the fresh food compartment 12. Opening the doors 22, 26 allows a user standing in front of the refrigeration appliance 10 to gain access to the interior of the fresh food compartment 12. According to certain illustrative embodiments, opening the doors 22, 26 can also optionally grant the user access to a drawer 30 that is removably received within a storage compartment 32 (
The refrigeration appliance 10 also includes a refrigeration system 18 shown schematically in
The refrigeration system 18 can be any suitable cooling system employing a refrigerant that undergoes a phase change from liquid to gas in an evaporator as is known in the art to remove heat from air being introduced into at least one of the fresh-food and freezer compartments 14, 16. Generally, a compressor can be provided to the refrigeration system 18 to compress gaseous refrigerant to a high-temperature, high-pressure gas that is condensed and partially cooled to a warm liquid by a condenser. The warm liquid refrigerant is exposed to an interior of an evaporator assembly comprising many heat-transferring fins, in which the refrigerant rapidly expands and vaporizes into a gas. The phase change extracts the latent heat of vaporization from the ambient environment of the evaporator, thereby cooling air blown over the evaporator to be introduced into at least one of the fresh food and freezer compartments 14, 16 to provide the desired cooling effect. The gaseous refrigerant is returned to the compressor and the cycle repeated as necessary.
The PCBA 42 can be dedicated for controlling the temperature in the storage compartment 32 independently of the temperature within at least one of the fresh food and freezer compartments 12, 14, and optionally independent of both. In other words, a user can input a desired temperature for storing the particular food in the drawer 30 within the storage compartment 32 independent of the target temperature established for one or both of the fresh food and freezer compartments 12, 14. The user can optionally input the desired temperature to be established within the drawer 30 by keying in a specific numerical temperature via the user interface 46, can utilize up/down temperature control buttons, or otherwise directly specify the desired temperature within the drawer 30. According to alternate embodiments, the user can optionally input the desired temperature to be established within the drawer 30 by pressing a button or otherwise manipulating an input device provided to the user interface 46 corresponding to a specific food, or type (e.g., meat, seafood, beverages, etc. . . . ) of food, to be stored in the drawer 30. Based on the selected food or type of food, a processing component such as a microprocessor provided to the PCBA 42, for example, can execute computer-executable instructions stored in a non-transitory computer-readable memory to select an appropriate temperature for the selected food or type of food. Yet other embodiments can include a user interface 46 that presents the user with both options for inputting the desired temperature within the drawer 30, or includes different input devices such as a touch-screen interface, control knob, etc. . . . allowing the user to control the desired temperature within the drawer 30.
With reference again to
For any of the above-mentioned embodiments, the lower conductor 52 can optionally be permanently secured adjacent to the bottom of the storage compartment 32 such that the removal of the lower conductor 52 can not be accomplished without subjecting a portion of the refrigeration appliance 10 to physical damage. For other embodiments, a tool that is specifically adapted to release the lower conductor 52 from the refrigeration appliance 10 and/or specific knowledge of the physical configuration of the refrigeration appliance 10 not possessed by a typical end user can optionally be required to remove the lower conductor 52. Installing the lower conductor 52 in this manner can serve to discourage, or optionally prevent users from attempting to remove or otherwise interact with the lower conductor 52.
The lower conductor 52 can be formed from any suitable electrically-conductive material such as a metal alloy, for example. A specific example of a suitable metal alloy is an aluminum alloy that includes a combination of aluminum with at least one of magnesium and silicon, such as 6061 aluminum alloy and, more specifically, 6061-T6 aluminum alloy, for example.
Additionally, an upper conductor 54 can optionally be provided adjacent to the top surface 44 of the storage compartment 32 that partitions a portion of the storage compartment 32 from the interior of the fresh food compartment 12. The upper conductor 54 can be installed within close proximity to the top surface 44, optionally installed in a substantially permanent manner, and formed from any suitable electrically-conductive material. As shown in
The conductor(s) 52, 54 are formed from any suitable electrically-conductive material, and can form an antenna such as a monopole antenna, for example, which is an ungrounded conductor with a small current consumption to emit an electromagnetic field. According to other embodiments, the conductor can act as an electrode when a return conductive path to a reference potential such as ground is established for the conductor(s) 52, 54. An alternating electric signal can be supplied to the lower conductor 52, the upper conductor 54, or both the lower and upper conductors 52, 54 under the control of a control system 60 (
According to alternate embodiment, one or both conductors 52, 54 can optionally be replaced or arranged in combination with a permanent magnet, electromagnet, and the like to establish a magnetic field in lieu of, or in addition to the electric field generated as a result of supplying the alternating electric signal to one or both conductors 52, 54. According to other embodiments, the electric field can be an electromagnetic field generated by supplying the alternating electric signal to one or both conductors 52, 54. However, for the sake of brevity, the field generated will be described herein as an electric field, which can also be accompanied by a magnetic field.
The supply signal can be any alternating electric signal such as the signal output from a conventional AC household receptacle supplied with electricity by an electric utility. In the U.S., such a supply signal has a voltage of approximately 115 V and a frequency of approximately 60 Hz before being converted into the alternating electric signal. In other jurisdictions, the supply signal can have a voltage of approximately 240 V, and a frequency of approximately 50 Hz.
Regardless of the particular supply signal converted, the alternating electric signal can be a sinusoidal, square wave, sawtooth wave, or any other oscillating signal. The alternating electric signal supplied by the control system 60 to the conductor(s) 52, 54 can also include a voltage that is greater than or equal to 1 kV, and optionally within a range from about 1 kV to about 10 kV. The frequency of the alternating electric signal supplied by the control system 60 can include a frequency of about 60 Hz, about 50 Hz, or any suitably-low value that is less than 1 kHz. For embodiments employing the lower and upper conductors 52, 54, the alternating electric signal supplied to each can be substantially in phase with the alternating electric signal supplied to the other. Further, the conductors 52, 54 are arranged to prevent the electric field 64 generated by each conductor 52, 54 from canceling or significantly interfering with the electric field 64 generated by the other one of the conductors 52, 54.
Supplying the alternating electric signal to the ungrounded lower conductor 52, upper conductor 54, or both conductors 52, 54 generates an electric field 64 that emanates from the one or more conductors 52, 54 supplied with the alternating electric signal. The conductor(s) 52, 54 are positioned such that the electric field 64 extends into the storage compartment 32, and optionally into the drawer 30, where food stored therein will be exposed to the electric field 64. This electric field 64 can have a field strength falling within a range from about 1 kV/m to about 150 kV/m.
The electric field 64 generated as described herein can interfere with the proper functioning of other control components such as the PCBA 42 that controls the temperature within the drawer 30, for example. To minimize the effect of such interference, a shield 66 formed from a material that is at least one of electrically-conductive and magnetic can at least partially separate the PCBA 42 or other control circuit from the conductors 52, 54, thereby at least partially protecting the PCBA 42 from the electric field 64. As shown in
The alternating electric signal can optionally be supplied to one or both electrodes 52, 54 in a manner to generate the electric field suitable to enhance the preservation of a particular food and/or type of food stored in the drawer 30. For example, the selection of a type of food input by a user via the user interface 46 described above can optionally be used by a computer processor or other suitable controller provided to the PCBA 42, for example, to determine a voltage, frequency, or combination of voltage and frequency of the alternating electric signal to be supplied to the one or more conductors 52, 54 for generating the electric field specifically suited for enhancing the preservation of the food and/or food type selected via the user interface 46.
The alternating electric signal can optionally be supplied to the one or more conductors 52, 54 in a plurality of different operational modes. For instance, based on the specific food and/or food type to be stored in the drawer 30 input via the user interface 46, or otherwise selected either directly or indirectly by the user, the alternating electric signal can optionally be supplied in a continuous mode, a pulsed mode, or a variable mode. In the continuous mode, the alternating electric signal can be supplied with a predetermined voltage and/or frequency suitable for enhancing the food and/or food type to be stored in the drawer 30 for as long as the food is stored in the drawer 30. Thus, in the continuous mode, the alternating electric signal is supplied substantially continuously while the food is stored in the drawer 30.
In the pulsed mode, the alternating electric signal with a predetermined voltage and/or frequency can be repeatedly delivered continuously during limited pulse periods of time. Each pulse period of time is substantially shorter than the time the food is stored in the drawer 30, and a plurality of pulses of the alternating electric signal are supplied to the one or more conductors 52, 54 while the food is stored in the drawer 30. For example, the alternating electric signal can be supplied to the lower conductor 52, the upper conductor 54, or both conductors 52, 54 for X seconds, where X is an integer that is greater than or equal to 2, for example, or any suitable duration. Delivery of the alternating electric signal to one or both conductors 52, 54 can then be terminated for a desired period of time before being restarted for the next pulse. Thus, in the pulsed operational mode, the alternating electric signal is repeatedly delivered to the one or more conductors 52, 54 (substantially in phase when delivered to both) and terminated while the food is stored in the drawer 30. Further, the duty cycle of the pulses of the alternating electric signal can optionally be independently determined for each pulse, and can vary among pulses.
In the variable operational mode, the alternating electric signal can optionally be supplied to the one or more conductors 52, 54 to generate the electric field with a variable voltage and/or frequency. Thus, the voltage and/or frequency can be initially established and vary during delivery of the alternating electric signal to one or both conductors 52, 54. However, the frequency can be maintained at a frequency less than 1 kHz and a voltage greater than or equal to 1 kV.
Illustrative embodiments have been described, hereinabove. It will be apparent to those skilled in the art that the above devices and methods may incorporate changes and modifications without departing from the general scope of this invention. It is intended to include all such modifications and alterations within the scope of the present invention. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.