NON-FREEZING STORAGE UNIT AND REFRIGERATOR INCLUDING THE SAME
The present invention relates to a non-freezing storage unit which can store food at a temperature below 0° C. without freezing the food, and a refrigerator including the same. The non-freezing storage unit includes an outer casing with one open surface, a drawer which can be pulled out and detached through the open surface of the outer casing, a sensor located on one surface of the outer casing and sensing a temperature of food located in the drawer, a thermal conductive member installed on one surface of the drawer facing the sensor and transferring the temperature of the food in the drawer to the sensor, and a heater installed in the outer casing. The non-freezing storage unit is located in a cooling space to store food in a non-frozen state at a temperature below 0° C.
Latest LG Electronics Patents:
The present invention relates to a non-freezing storage unit which can store food at a temperature below 0° C. without freezing the food, and a refrigerator including the same.
BACKGROUND ARTSupercooling means the phenomenon that a molten object or a solid is not changed although it is cooled to a temperature below a phase transition temperature in an equilibrium state. A material has a stable state at every temperature. If the temperature is slowly changed, the constituent elements of the material can follow the temperature changes, maintaining the stable state at each temperature. However, if the temperature is suddenly changed, since the constituent elements cannot be changed into the stable state at each temperature, the constituent elements maintain a stable state at an initial temperature, or some of the constituent elements fail to be changed into a state at a final temperature.
For example, when water is slowly cooled, it is not temporarily frozen at a temperature below 0° C. However, when water enters a supercooled state, it has a kind of quasi-stable state. As this unstable equilibrium state is easily broken even by slight stimulation, water tends to move into a more stable state. That is, if a small piece of the material is put into the supercooled liquid, or if the liquid is suddenly shaken, the liquid starts to be frozen at once such that the temperature of the liquid reaches the freezing point, and maintains a stable equilibrium state at the temperature. In general, an electrostatic atmosphere is made in a refrigerator, and meat and fish are thawed in the refrigerator at a minus temperature. In addition to the meat and fish, fruit is kept fresh in the refrigerator.
This technology uses a supercooling phenomenon. The supercooling phenomenon indicates the phenomenon that a molten object or a solid is not changed although it is cooled to a temperature below a phase transition temperature in an equilibrium state.
This technology includes Korean Patent Publication No. 2000-0011081 which discloses an electrostatic field processing method, an electrostatic field processing apparatus, and electrodes therefor.
Target objects to be thawed or freshness-kept and ripened such as vegetables, meat and marine products are loaded on the respective layers. The metal shelf 7 is insulated from the bottom of the room 1 by an insulator 9. In addition, since a high voltage generator 3 can generate 0 to 5000 V of DC and AC voltages, an insulation plate 2a such as vinyl chloride, etc. is covered on the inside of the insulation material 2. A high-voltage cable 4 outputting the voltage of the high voltage generator 3 is connected to the metal shelf 7 after passing through the outer wall 5 and the insulation material 2.
When a user opens a door installed at the front of the keeping-cool room 1, a safety switch 13 (see
The applied voltage is regulated by a regulation knob 15a on a secondary side of the voltage regulation transformer 15, and the regulated voltage value is displayed on a voltmeter. The regulation knob 15a is connected to a primary side of a boosting transformer 17 at the secondary side of the voltage regulation transformer 15. The boosting transformer 17 boosts the voltage at a ratio of 1:50. For example, when 60 V of voltage is applied, it is boosted to 3000 V.
One end O1 of the output of the secondary side of the boosting transformer 17 is connected to the metal shelf 7 insulated from the keeping-cool room 1 through the high-voltage cable 4, and the other end O2 of the output is grounded. Moreover, since the outer wall 5 is grounded, if the user touches the outer wall 5 of the keeping-cool room 1, he/she does not get an electric shock. Further, in
In the prior art, an electric field or magnetic field is applied to the received object to be cooled such that the received object reaches a supercooled state. Accordingly, a complicated apparatus for producing the electric field or magnetic field should be provided to keep the received object in the supercooled state, and the power consumption is increased during the production of the electric field or magnetic field. Additionally, the apparatus for producing the electric field or magnetic field should further include a safety device (e.g., an electric field or magnetic field shielding structure, an interception device, etc.) for protecting the user from high power, when producing or intercepting the electric field or magnetic field.
DISCLOSURE Technical ProblemAn object of the present invention is to provide a non-freezing storage unit in which a drawer can be completely pulled out of an outer casing.
Another object of the present invention is to provide a non-freezing storage unit which can maintain a received object in a supercooled state via power supply in a space where only the cooling is performed.
A further object of the present invention is to provide a non-freezing storage unit which can selectively perform the supercooled state control and the frozen state control on a received object.
A still further object of the present invention is to provide a non-freezing storage unit which can accomplish the convenience of the reception of a received object and the accurate sensing of a temperature of the received object.
A still further object of the present invention is to provide a non-freezing storage unit in which a control unit performing the supercooled state control and the frozen state control is separated from a receiving space of a received object and mounted on a side surface of the unit.
A still further object of the present invention is to provide a temperature change room in which the cooling/heating can be switched using a thermoelectric element, although an evaporator is not additionally included in a refrigerator.
A still further object of the present invention is to provide a temperature change room which can serve as a non-freezing room which can store food in a non-frozen supercooled state by adjusting a temperature of a thermoelectric element.
Technical SolutionAccording to an aspect of the present invention, there is provided a non-freezing storage unit, including: an outer casing with one open surface; a drawer which can be pulled out and detached through the open surface of the outer casing; a sensor located on one surface of the outer casing and sensing a temperature of food located in the drawer; a thermal conductive member installed on one surface of the drawer facing the sensor and transferring the temperature of the food in the drawer to the sensor; and a heater installed in the outer casing, wherein the non-freezing storage unit is located in a cooling space to store food in a non-frozen state at a temperature below 0° C. In addition, an insulation material is filled in the outer casing.
Moreover, the thermal conductive member includes a metal plate located on a bottom surface of the drawer and receiving a temperature change of the food, and a contact point portion transferring the temperature change between the metal plate and the sensor.
Further, the contact point portion is downwardly protruded from the bottom surface of the drawer.
Furthermore, a handle for use in pulling the drawer out is provided on one surface of the drawer corresponding to the open surface of the outer casing. Still furthermore, the handle includes a grip portion and a hook portion moved in cooperation with the grip portion, and the outer casing includes a hooked portion on which the hook portion is hooked.
Still furthermore, a gasket for use in sealing up the inner space is provided on one surface of the drawer corresponding to the open surface of the outer casing.
Still furthermore, the outer casing and the drawer include guide portions for guiding the movement of the drawer, respectively, and the guide portions guide the drawer so that the drawer can be located lower in the outer casing than during the movement, when the drawer is completely inserted into the outer casing.
Still furthermore, when the drawer is inserted into the outer casing and downwardly moved by the guide portions, the sensor and the thermal conductive member are brought into contact with each other.
Still furthermore, the non-freezing storage unit further includes a fan installed in the outer casing and producing the flow of the air in the unit.
Still furthermore, the heater includes an upper heater installed on an inside top surface of the outer casing and a lower heater installed on an inside bottom surface of the outer casing.
Still furthermore, the non-freezing storage unit further includes a sensor for sensing a temperature in the unit which is installed at an upper portion of the outer casing and senses a temperature of the air in the drawer.
Still furthermore, a heating value of the upper heater is adjusted according to the temperature measured by the sensor for sensing the temperature in the unit, and a heating value of the lower heater is adjusted according to the temperature measured by the sensor.
Still furthermore, the heating values of the upper heater and the lower heater are controlled so that the temperature in the inside upper portion of the unit can be higher than the temperature in the inside lower portion of the unit by about 1 to 2° C.
Still furthermore, at least one of the upper heater and the lower heater includes a plurality of individual heaters, at least one of the plurality of individual heaters is constantly operated, and the other individual heaters are turned on/off according to the temperature in the unit.
Still furthermore, the non-freezing storage unit further includes a side casing located on a side surface of the outer casing and having a display portion and a button portion at the front.
Still furthermore, the non-freezing storage unit further includes a control panel installed in the side casing, cooperating with the display portion, the button portion and the sensor, and controlling electric components in the unit.
Still furthermore, the heater is a thermoelectric element having the flowing current and voltage controlled to adjust the temperature in the non-freezing storage unit.
Meanwhile, there is provided a refrigerator, including: a non-freezing storage unit described above; and a cooling space cooled by a freezing cycle and having the non-freezing storage unit therein.
In addition, a temperature in the non-freezing storage unit is maintained at about −2° C. to −4° C., raised to normal temperature when it is determined that the food has been frozen on the basis of a food temperature change sensed by a sensor, and lowered again to −2° C. to −4° C. to store the food.
Advantageous EffectsAccording to the temperature change room of the refrigerator of the present invention, the temperature change room is implemented using the thermoelectric element. Therefore, when it is intended to store the food at a temperature lower than a temperature in a refrigerating chamber, it is not necessary to introduce the cool air of a freezing chamber into the temperature change room. A damper or the like is not necessary, which simplifies the structure of the refrigerator.
In addition, according to the temperature change room of the refrigerator of the present invention, the heating can be performed in the temperature change room using the thermoelectric element. It is thus not necessary to install two or more evaporators to utilize a heating function.
Moreover, according to the temperature change room of the refrigerator of the present invention, the temperature in the temperature change room can be adjusted regardless of the operation conditions of the refrigerating chamber and the freezing chamber.
Further, according to the non-freezing storage unit provided by the present invention, the drawer can be completely detached from the outer casing, which improves the convenience of the use.
Furthermore, according to the non-freezing storage unit provided by the present invention, the sensor is installed in the outer casing and more sensitively senses the temperature of the food. This improves the non-freezing stability and enables easy determination on the release of the non-frozen state.
Still furthermore, according to the non-freezing storage unit provided by the present invention, the operation panel and the control panel irrelevant to the refrigerator are installed at one side of the non-freezing storage unit to thereby easily control the functions of the non-freezing storage unit.
Still furthermore, according to the non-freezing storage unit provided by the present invention, the plurality of heaters are provided to perform the non-freezing function. In a state where one or more heaters are always in operation, the other heaters are used to adjust the heating value. It is thus possible to reduce the temperature fluctuation range in the non-freezing storage unit influenced by the adjustment of the heating value of the heater. It is also possible to reduce the influence on the sensor exerted by the change in the heating value of the heater. This improves the sensitivity of the sensor to the release of the non-frozen state.
Hereinafter, the present invention will be described in detail with reference to the exemplary embodiments and the accompanying drawings.
For example, it is assumed that a cooling temperature in the cooling space is lowered from a normal temperature to a temperature below 0° C. (a phase transition temperature of water) or a temperature below a phase transition temperature of the liquid L. While the cooling is carried out, it is intended to maintain a supercooled state of the water or the liquid L (or the received object) at a temperature below the maximum ice crystal formation zone (−1° C. to −7° C.) of the water in which the formation of ice crystals is maximized, or at a cooling temperature below the maximum ice crystal formation zone of the liquid L.
The liquid L is evaporated during the cooling such that vapor W1 is introduced into a gas Lg (or a space) in the container C. In a case where the container C is closed, the gas Lg may be supersaturated due to the evaporated vapor W1.
When the cooling temperature reaches or exceeds a temperature of the maximum ice crystal formation zone of the liquid L, the vapor W1 forms ice crystal nucleuses F1 in the gas Lg or ice crystal nucleuses F2 on an inner wall of the container C. Alternatively, the condensation occurs in a contact portion of the surface Ls of the liquid L and the inner wall of the container C (almost the same as the cooling temperature in the cooling space) such that the condensed liquid L may form ice crystal nucleuses F3 which are ice crystals.
For example, when the ice crystal nucleuses F1 in the gas Lg are lowered and infiltrated into the liquid L through the surface Ls of the liquid L, the liquid L is released from the supercooled state and caused to be frozen. That is, the supercooling of the liquid L is released.
Alternatively, as the ice crystal nucleuses F3 are brought into contact with the surface Ls of the liquid L, the liquid L is released from the supercooled state and caused to be frozen.
As described above, according to the process of forming the ice crystal nucleuses F1 to F3, when the liquid L is stored at a temperature below its maximum ice crystal formation zone, the liquid L is released from the supercooled state due to the freezing of the vapor evaporated from the liquid L and existing on the surface Ls of the liquid L and the freezing of the vapor on the inner wall of the container C adjacent to the surface Ls of the liquid L.
In
Accordingly, the liquid L in the container C maintains the supercooled state at a temperature below its phase transition temperature or a temperature below its maximum ice crystal formation zone.
Moreover, when the cooling temperature in the storing unit S is a considerably low temperature, e.g., −20° C., although the energy is applied to an upper portion of the container C, the liquid L which is the received object may not be able to maintain the supercooled state. There is a need that the energy should be applied to a lower portion of the container C to some extent. When the energy applied to the upper portion of the container C is relatively larger than the energy applied to the lower portion of the container C, the temperature in the upper portion of the container C can be maintained higher than the phase transition temperature or a temperature of the maximum ice crystal formation zone. Further, the temperature of the liquid L in the supercooled state can be adjusted by the energy applied to the lower portion of the container C and the energy applied to the upper portion of the container C.
The liquid L has been described as an example with reference to
Furthermore, the energy adopted in the present invention may be thermal energy, electric or magnetic energy, ultrasonic energy, light energy, and so on.
The apparatus for supercooling of
The apparatus for supercooling is installed in the storing unit S such that the cooling is performed therein. The temperature sensors C1 and C2 sense the temperature and the heating coils H1 and H2 are turned on to supply heat from the upper and lower portions of the receiving space to the receiving space. The heat supply quantity is adjusted to control the temperature in the upper portion of the receiving space (or the air on the received object P) to be higher than a temperature of the maximum ice crystal formation zone, more preferably, the phase transition temperature.
The positions of the heating coils H1 and H2 in
As illustrated in
As shown, in a case where the cooling temperature is maintained at about −19° C. to −20° C. (see line I), when the temperature of the gas Lg on the surface of the water in the container C is maintained at about 4° C., to 6° C. which is higher than a temperature of the maximum ice crystal formation zone of the water, the temperature of the water in the container C is maintained at about −11° C. which is lower than a temperature of the maximum ice crystal formation zone of the water, but the water is stably maintained in a supercooled state which is a liquid state for an extended period of time. Here, the heating coils H1 and H2 supply heat.
Additionally, in
The non-freezing storage unit according to the first embodiment of the present invention roughly includes an outer casing 100, a drawer 200 and a side casing 300. The drawer 200 can be inserted into and pulled out of the outer casing 100. As any separate electronic device is not attached to the drawer 200, the drawer 200 can be completely separated and detached from the outer casing 100. The outer casing 100 includes an insulation material 110 to insulate the non-freezing storage unit from the other region of a refrigerator in which the non-freezing storage unit is located. The drawer 200 and the side casing 300 also include insulation materials 210 and 310, respectively. It is thus possible to insulate the portions which are not sufficiently insulated by the insulation material 110 of the outer casing 100. Heaters 140 are installed on the inside of the outer casing 100. A control unit (not shown) adjusts heating values of the heaters 140 to control a temperature in the non-freezing storage unit. The heaters 140 include an upper heater 142 and a lower heater 144, and the control unit (not shown) control the heating values of the upper heater 142 and the lower heater 144, respectively. In addition, a sensor 132 for sensing a temperature in the unit which measures the temperature in the non-freezing storage unit is installed on the upper side of the outer casing 100. In order to minimize the influence on the sensor 132 for sensing the temperature in the unit exerted by the heat of the heaters 140, the heaters 140 may not be located adjacent to the sensor 132 for sensing the temperature in the unit, and a separate insulation member (not shown) may be further installed between the heaters 140 and the sensor 132 for sensing the temperature in the unit. Moreover, sensors 134 and 136 sensing a temperature of food are provided on the lower side of the outer casing 100. The sensors 134 and 136 measure the temperature of the food located in the drawer 200. Preferably, a plurality of sensors 134 and 136 are installed at given intervals to reflect the temperature of the food to the operation of the non-freezing storage unit, when the food is widely distributed in the drawer 200. In this embodiment, although two sensors 134 and 136 are installed, three or more sensors may be installed. As the sensors 134 and 136 are not installed in the drawer 200 brought into contact with the food but in the outer casing 100, a cable for use in transferring power to the sensors 134 and 136 and receiving temperature sensing information therefrom can be removed from the drawer 200. There is an advantage in that the drawer 200 can be completely pulled out of the outer casing 100. If the drawer 200 is not completely pulled out of the outer casing 100, it is inconvenient to put the food into the drawer 200 or take the food out of the drawer 200 and very difficult to clean the drawer 200. The sensors 134 and 136 are attached to bottom surfaces of sensor installation portions 134a and 136a of a thin metal plate attached to the bottom surface of the outer casing 100, and thus are not exposed to the outside of the outer casing 100.
The guide portions 120 and 220 include rails 122 and 222 and rollers 124 and 224, respectively. When the drawer 200 is inserted into the outer casing 100, the rollers 124 and 224 of the outer casing 100 and the drawer 200 are brought into contact with each other. Next, the rollers 224 of the drawer 200 roll over the rails 122 of the outer casing 100 and the rails 222 of the drawer 200 roll over the rollers 124 of the outer casing 100 at the same time such that the drawer 200 is inserted into the outer casing 100. The rails 122 of the outer casing 100 are inclined to the lower portion so that the drawer 200 can be downwardly moved at the back of the outer casing 100. In order to prevent the rollers 224 of the drawer 200 from being separated from the rails 122 of the outer casing 100 due to the inclined portions, preferably, the rear portions of the rails 122 are blocked in a width to accommodate the rollers 224. Additionally, to prevent the interference between the drawer 200 and the rollers 124 of the outer casing 100 when the drawer 200 is downwardly moved at the back of the outer casing 100, stepped portions are formed at the front of the rails 222 of the drawer 200 to accommodate the rollers 124 of the outer casing 100. Therefore, referring to the drawings, while the drawer 200 is inserted into the outer casing 100 and moved therein, the contact point portions 234 and 236 can be moved without any interference and friction, maintaining a given interval from the bottom surface of the outer casing 100. Moreover, after the drawer 200 is completely inserted into the outer casing 100, the drawer 200 is downwardly moved by the guide portions 120 and 220 and the contact point portions 234 and 236 are completely in contact with the sensor installation portions 134a and 136a.
When taking the drawer 200 out of the outer casing 100 or inserting the drawer 200 into the outer casing 100, a user can insert or take out the drawer 200 by holding the cover 250 portion. For the user's convenience, a handle 252 is formed at the cover 250 portion. Any shape of handle 252 may be used as far as it helps the user to easily take the drawer 200 out of the casing 100. However, for the convenience of the use, the handle 252 is formed in the shape of a groove on the lower side of the front surface of the cover 250 so that the user can release the locked state of the hook portion 272 and pull the drawer 200 out at the same time by gripping the grip portion 276. If the position of the grip portion 276 is changed, the position of the handle 252 may also be changed so that the user can grip the grip portion 276 and pull the drawer 200 out at the same time.
As set forth herein, the non-freezing storage unit should be certainly insulated from the other region of the refrigerator to stably maintain the non-frozen state of the food. Here, a portion in which heat exchange with the other region of the refrigerator or heat leakage probably occurs is a gap between the drawer 200 and the outer casing 100 located at the front.
Accordingly, in order to ensure the insulation of the drawer 200 and the outer casing 100, the gasket 260 is attached to a rear portion of the front frame 240 brought into contact with a front portion of the outer casing 100. The gasket 260 is made of an elastic material such as natural rubber or synthetic rubber and transformed between the drawer 200 and the outer casing 100 by a force applied from the drawer 200 and the outer casing 100, thereby sealing up the gap between the drawer 200 and the outer casing 100.
As described above, when the drawer 200 is completely inserted into the outer casing 100, the drawer 200 is downwardly guided by the guide portions 120 and 220 (see
The insulation material 310, a control panel (not shown), a control panel mounting portion 320, an operation panel (not shown) and an operation panel mounting portion 330 are installed in the side casing 300. The operation panel (not shown), which includes a button portion 315a, 315b, 315c and 315d enabling the input of functions of the non-freezing storage unit and a display portion 316 displaying the selected function, displays the function input through the button portion 315a, 315b, 315c and 315d on the display portion 316 and transmits information on the inputted function to the control panel (not shown). Preferably, a window (hole) is provided in a corresponding position of the side casing 300 to expose the button portion 315a, 315b, 315c and 315d and the display portion 316 of the PCB operation substrate to the outside. The button portion 315a, 315b, 315c and 315d and the display portion 316 are not located on the drawing 200 but on the side casing 300 such that the drawing 200 is completely detachable from the outer casing 100. The button portion 315a, 315b, 315c and 315d includes a button 315a selecting a thin ice function, a button 315b selecting a freezing function, a button 315c selecting a supercooling function, and a button 315d turning on and off power of the non-freezing storage unit. The display portion 316 displays the power-on/off state of the non-freezing storage unit and the function currently performed in the non-freezing storage unit. When the user turns on power of the non-freezing storage unit through the button 315d and selects the thin ice function through the button 315a, the control panel (not shown) receives an input signal from the button 315a and displays that the refrigerating function has been selected through the display portion 316. In addition, the control panel (not shown) adjusts the heating values of the heaters 140 installed in the outer casing 100 (see
In addition, while the meat is stored in the non-freezing storage unit by the non-freezing function, its non-frozen state may be broken due to a shock or partial temperature unbalance. Even if ice crystals are formed in some part, the freezing may be easily spread to the entire meat. Once the freezing is started, the temperature is suddenly raised to near 0° C. which is the phase transition temperature. Therefore, when a sudden temperature change is sensed by the sensors 134 and 136, it is determined that the stored food such as the meat, etc. has been frozen. The food in the non-freezing storage unit is thawed, and then stored again in the non-frozen state. To thaw the food in the non-freezing storage unit, preferably, the temperature is raised to near normal temperature, at least 2° C. and maintained for a given time such that the food is sufficiently thawed and stored again in the non-frozen state. Moreover, when the user selects the non-freezing function, the control panel (not shown) may adjust the heating values of the heaters 140 via a given algorithm using the sensor 132 for sensing the temperature in the unit and the sensors 134 and 136 so that the temperature in the unit can be maintained at −2° C. to −4° C. However, the control panel (not shown) may adjust the heating value of the upper heater 142 merely using the temperature sensed by the sensor 132 for sensing the temperature in the unit such that the temperature in the upper portion of the non-freezing storage unit is maintained at about −2° C., and may adjust the heating value of the lower heater 144 merely using the temperature sensed by the sensors 134 and 136 such that the temperature in the lower portion of the non-freezing storage unit is maintained at about −3° C. to −4° C.
Meanwhile, a box fan (not shown) may be installed in one side of the inner space of the outer casing 100 (e.g., the rear portion of the outer casing) where there is no interference between the outer casing 100 and the drawer 200 or the inner space of the side casing 300 so as to produce the forcible flow in the non-freezing storage unit. If the box fan (not shown) is provided in the inner space of the side casing 300, a flow vent (not shown) should be further formed between the side casing 300 and the outer casing 100 so that the forcible flow caused by the box fan can be produced in the outer casing 100 in which the basket 230 is located. In a case where the box fan (not shown) is installed to produce the forcible flow, the temperature distribution in the non-freezing storage unit becomes uniform, and thus the sensitivity of the sensors 134 and 136 sensing the release of the non-frozen state is improved.
Further, each of the heaters 140, i.e., the upper heater 142 and the lower heater 144 may include a plurality of heaters. When the non-freezing storage unit performs the non-freezing function, the plurality of upper heaters 142 and lower heaters 144 are operated in a state where at least one heater is always on and the other heaters are on/off according to the temperature measured by the sensor 132 for sensing the temperature in the unit and the sensors 134 and 136. When the upper heater 142 and the lower heater 144 are composed of the plurality of heaters, respectively, the temperature fluctuation range in the unit influenced by the heating value of the heater is small compared with the on/off of a single heater. Thus, it is easy to distinguish the temperature fluctuation caused by the on/off of the heater from the temperature fluctuation caused by the release of the supercooling. Compared with a large temperature fluctuation range, a small temperature fluctuation range can improve the supercooling stability and the freshness of the food.
A thermoelectric element 111 is installed on the inside of the outer casing 110. According to the direction of the current applied to the thermoelectric element 111, the temperature is lowered at one side for cooling and raised at the other side for heating. In the non-freezing storage unit 100 of the present invention, the temperature in the non-freezing storage unit 100 is adjusted using the thermoelectric element 111, instead of using the general hotwire heater and the cool air of the refrigerating chamber or the freezing chamber. When it is intended to lower the temperature in the non-freezing storage unit 100, the direction of the current of the thermoelectric element 111 is adjusted to transfer the temperature change on the cooling side into the non-freezing storage unit 100, and when it is intended to raise the temperature in the non-freezing storage unit 100, the direction of the current of the thermoelectric element 111 is adjusted to transfer the temperature change on the heating side into the non-freezing storage unit 100. As the temperature in the non-freezing storage unit 100 is adjusted through the thermoelectric element 111, although the non-freezing storage unit 100 is installed in the refrigerating chamber, the temperature in the non-freezing storage unit 100 can be controlled to be lower than that of the refrigerating chamber. The non-freezing storage unit 100 further includes a conductor 112 which is in contact with the thermoelectric element 111 so that the temperature change of the thermoelectric element 111 can be evenly transferred into the non-freezing storage unit 100. Preferably, the conductor 112 is formed to cover the entire inner surface of the outer casing 110.
The relative installation positions of the outer casing 110, the thermoelectric element 111 and the conductor 112 will be described. The thermoelectric element 111 may be installed on the inner surface of the outer casing 110, and then the conductor 112 may be installed to cover the thermoelectric element 111. The temperature change on one side of the thermoelectric element 111 which is in contact with the conductor 112 is conducted through the conductor 112 and evenly transferred into the non-freezing storage unit 100, and the temperature change on the other side of the thermoelectric element 111 is insulated by the insulation material 113 of the outer casing 110 and prevented from being transferred into the refrigerating chamber or the freezing chamber in which the non-freezing storage unit 100 is located. One or plural thermoelectric elements 111 may be installed on the upper side of the inner surface of the outer casing 110, and one or plural thermoelectric elements 111 may be installed on the upper side and the lower side thereof, respectively. The thermoelectric element 111 is connected to a control unit (not shown), and the control unit (not shown) controls the direction and amplitude of the current flowing through the thermoelectric element 111 to maintain a set temperature input by a user or a temperature preset in the control unit (not shown).
For another example, the conductor 112 may be installed on the inner surface of the outer casing 110, and then the thermoelectric element 111 may be installed in contact with the conductor 112. Here, one side of the thermoelectric element 111 is in contact with the conductor 112 and the other side thereof is exposed in the non-freezing storage unit 100. As illustrated in
To perform the non-freezing function, the non-freezing storage unit 100 needs a sensor 114 which can measure the temperature inside the non-freezing storage unit 100 or the temperature of the stored food. Referring to
In the meantime, to control the functions of the non-freezing storage unit 100, operation portions 115a, 115b, 115c and 115d enabling the input of the functions and a display portion 116 displaying the working state of the non-freezing storage unit 100 are provided at the front of the non-freezing storage unit 100. Preferably, the operation portions 115a, 115b, 115c and 115d and the display portion 116 are not installed on the drawer 120 but on one side of the front of the outer casing 110 so that the drawer 120 can be completely detached from the outer casing 110. If a module is provided to wirelessly transmit and receive power and information between the outer casing 110 and the drawer 120, the operation portions 115a, 115b, 115c and 115d and the display portion 116 may be installed on the drawer 120, which increases the manufacturing costs.
The operation portions 115a, 115b, 115c and 115d include an operation portion 115a selecting a refrigerating function, an operation portion 115b selecting a heating function, an operation portion 115c selecting a supercooling function, and an operation portion 115d turning on and off power of the non-freezing storage unit 100. The display portion 116 displays the power-on/off state of the non-freezing storage unit 100 and the function currently performed in the non-freezing storage unit 100. When the user turns on power of the non-freezing storage unit 100 through the operation portion 115d and selects the refrigerating function through the operation portion 115a, the control unit (not shown) receives an input signal from the operation portion 115a and displays that the refrigerating function has been selected through the display portion 116. In addition, the control unit (not shown) selects the direction of the current flowing to the thermoelectric element 111 through the cable 111a so that the side of the thermoelectric element 111 which is in contact with the conductor 112 can be the cooling side. When the user selects the heating function through the operation portion 115b, the control unit (not shown) selects the direction of the current flowing to the thermoelectric element 111 so that the side of the thermoelectric element 111 which is in contact with the conductor 112 can be the heating side. Moreover, when the user selects the non-freezing function through the operation portion 115c, the control unit (not shown) selects the direction and amplitude of the current flowing to the thermoelectric element 111 so that the temperature in the non-freezing storage unit 100 can be maintained at about −2° C. to −4° C. For this purpose, the control unit (not shown) continuously senses the temperature of the food measured by the sensor 114 and appropriately controls the direction and amplitude of the current according to the sensed food temperature such that the temperature in the non-freezing storage unit 100 is maintained at about −2° C. to −4° C. When the meat or the like is stored at a temperature below 0° C. without being frozen by the non-freezing function, it is possible to prevent the taste from being reduced by the ice crystal formation in the meat and the destruction of fibers of the meat.
In the meantime, while the meat is stored in the non-freezing storage unit 100 by the non-freezing function, its non-frozen state may be broken due to a shock or partial temperature unbalance. Even if ice crystals are formed in some part, the freezing may be easily spread to the entire meat. Once the freezing is started, the temperature is suddenly raised to near 0° C. which is the phase transition temperature. Therefore, when a sudden temperature change is sensed by the sensor 114, it is determined that the stored food such as the meat, etc. has been frozen. The food in the non-freezing storage unit 100 is thawed, and then stored again in the non-frozen state. To thaw the food in the non-freezing storage unit 100, preferably, the temperature is raised to near normal temperature, at least 2° C. and maintained for a given time such that the food is sufficiently thawed and stored again in the non-frozen state.
Furthermore, preferably, a sensor 117 measuring a temperature in the non-freezing storage unit 100 and/or a sensor 114 measuring a temperature of food stored in the non-freezing storage unit 100 are installed in the non-freezing storage unit 100. The sensor 114 transfers the sensed temperature information to a control unit (not shown), and the control unit (not shown) controls the direction and intensity of the current applied to the thermoelectric element 111 according to the temperature information sensed by the sensor 114. With respect to the control unit (not shown), a separate control unit (not shown) irrelevant to a refrigerator main body may be provided in the casing 110 or the refrigerator main body to control the functions of the non-freezing storage unit 100, or a control unit (not shown) of the refrigerator main body may serve to control the functions of the non-freezing storage unit 100. The control unit (not shown) can control the functions of the non-freezing storage unit 100 using the same method as that of the first or second embodiment.
Claims
1. A non-freezing storage unit, comprising:
- an outer casing with one open surface;
- a drawer which can be pulled out and detached through the open surface of the outer casing;
- a sensor located on one surface of the outer casing and sensing a temperature of food located in the drawer;
- a thermal conductive member installed on one surface of the drawer facing the sensor and transferring the temperature of the food in the drawer to the sensor; and
- a heater installed in the outer casing,
- wherein the non-freezing storage unit is located in a cooling space to store food in a non-frozen state at a temperature below 0° C.
2. The non-freezing storage unit of claim 1, wherein an insulation material is filled in the outer casing.
3. The non-freezing storage unit of claim 1, wherein the thermal conductive member comprises a metal plate located on a bottom surface of the drawer and receiving a temperature change of the food, and a contact point portion transferring the temperature change between the metal plate and the sensor.
4. The non-freezing storage unit of claim 3, wherein the contact point portion is downwardly protruded from the bottom surface of the drawer.
5. The non-freezing storage unit of claim 1, wherein a handle for use in pulling the drawer out is provided on one surface of the drawer corresponding to the open surface of the outer casing.
6. The non-freezing storage unit of claim 5, wherein the handle comprises a grip portion and a hook portion moved in cooperation with the grip portion, and the outer casing comprises a hooked portion on which the hook portion is hooked.
7. The non-freezing storage unit of claim 1, wherein a gasket for use in sealing up the inner space is provided on one surface of the drawer corresponding to the open surface of the outer casing.
8. The non-freezing storage unit of claim 1, wherein the outer casing and the drawer comprise guide portions for guiding the movement of the drawer, respectively, and the guide portions guide the drawer so that the drawer can be located lower in the outer casing than during the movement, when the drawer is completely inserted into the outer casing.
9. The non-freezing storage unit of claim 8, wherein, when the drawer is inserted into the outer casing and downwardly moved by the guide portions, the sensor and the thermal conductive member are brought into contact with each other.
10. The non-freezing storage unit of claim 1, further comprising a fan installed in the outer casing and producing the flow of the air in the unit.
11. The non-freezing storage unit of claim 1, wherein the heater comprises an upper heater installed on an inside top surface of the outer casing and a lower heater installed on an inside bottom surface of the outer casing.
12. The non-freezing storage unit of claim 11, further comprising a sensor for sensing a temperature in the unit which is installed at an upper portion of the outer casing and senses a temperature of the air in the drawer.
13. The non-freezing storage unit of claim 12, wherein a heating value of the upper heater is adjusted according to the temperature measured by the sensor for sensing the temperature in the unit, and a heating value of the lower heater is adjusted according to the temperature measured by the sensor.
14. The non-freezing storage unit of claim 12, wherein the heating values of the upper heater and the lower heater are controlled so that the temperature in the inside upper portion of the unit can be higher than the temperature in the inside lower portion of the unit by about 1 to 2° C.
15. The non-freezing storage unit of claim 12, wherein at least one of the upper heater and the lower heater comprises a plurality of individual heaters, at least one of the plurality of individual heaters is constantly operated, and the other individual heaters are turned on/off according to the temperature in the unit.
16. The non-freezing storage unit of claim 1, further comprising a side casing located on a side surface of the outer casing and having a display portion and a button portion at the front.
17. The non-freezing storage unit of claim 16, further comprising a control panel installed in the side casing, cooperating with the display portion, the button portion and the sensor, and controlling electric components in the unit.
18. The non-freezing storage unit of claim 1, wherein the heater is a thermoelectric element having the flowing current and voltage controlled to adjust the temperature in the non-freezing storage unit.
19. A refrigerator comprising:
- a non-freezing storage unit as recited claim 1; and
- a cooling space cooled by a freezing cycle and having the non-freezing storage unit therein.
20. The refrigerator of claim 19, wherein a temperature in the non-freezing storage unit is maintained at about −2° C. to −4° C., raised to normal temperature when it is determined that the food has been frozen on the basis of a food temperature change sensed by a sensor, and lowered again to −2° C. to −4° C. to store the food.
Type: Application
Filed: Dec 10, 2009
Publication Date: Sep 15, 2011
Applicant: LG Electronics, Inc. (Seoul)
Inventors: Deok-Hyun Youn (Gyeongsangnam-do), Sang-Ho Oh (Daegu), Hoon-Bong Lee (Gyeongsangnam-do)
Application Number: 13/128,377
International Classification: F25D 23/12 (20060101);