NON-FREEZING STORAGE UNIT

Abstract

The present invention discloses a non-freezing storage unit including an outer casing with an open front surface, a drawer which can be pulled out through the open front surface of the outer casing, a sensor installed on the outer casing and/or the drawer, a heater installed in the outer casing, and an air layer formed at the front of the drawer to intercept the cool air. 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.

Description

TECHNICAL FIELD

The present invention relates to a non-freezing storage unit, and, more particularly to, a non-freezing storage unit which can store food requiring high-level freshness, such as meat and vegetables, at a temperature below 0° C. without freezing the food.

BACKGROUND ART

Supercooling means the phenomenon that a molten object or a solid is not changed although it is cooled to a temperature below the 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 to the stable state at each temperature, the constituent elements maintain a stable state of the initial temperature, or some of the constituent elements fail to be changed to a state of the 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 to a more stable state. That is, if a small piece of material is put into the supercooled liquid, or if the liquid is suddenly shaken, the liquid starts to be frozen at once such that its temperature reaches the freezing point, and maintains a stable equilibrium state at this 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 the phase transition temperature in an equilibrium state.

This technology includes Korean Patent Publication No. 2000-0011081 titled “Electrostatic field processing method, electrostatic field processing apparatus, and electrodes therefor”.

FIG. 1 is a view of an example of a conventional thawing and freshness-keeping apparatus. A keeping-cool room 1 is composed of a thermal insulation material 2 and an outer wall 5. A mechanism (not shown) controlling a temperature inside the room 1 is installed therein. A metal shelf 7 installed in the room 1 has a two-layer structure. 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 thermal 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 thermal insulation material 2. When a user opens a door installed at the front of the keeping-cool room 1, a safety switch 13 (see FIG. 2) is turned off to intercept the output of the high voltage generator 3.

FIG. 2 is a circuit view of the circuit configuration of the high voltage generator 3. 100 V of AC is supplied to a primary side of a voltage regulation transformer 15. Reference numeral 11 represents a power lamp and 19 a working state lamp. When the door 6 is closed and the safety switch 13 is on, a relay 14 is operated. This state is displayed by a relay operation lamp 12. Relay contact points 14a, 14b and 14c are closed by the operation of the relay 14, and 100 V of AC is applied to the primary side of the voltage regulation transformer 15.

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 on 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 0₁ 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 0₂ 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 FIG. 1, when the metal shelf 7 is exposed in the room 1, it should be maintained in an insulated state in the room 1. Thus, the metal shelf 7 needs to be separated from the wall of the room 1 (the air performs an insulation function). Furthermore, if a target object 8 is protruded from the metal shelf 7 and brought into contact with the wall of the room 1, the current flows to the ground through the wall of the room 1. Therefore, the insulation plate 2a is attached to the inner wall to prevent drop of the applied voltage. Still furthermore, when the metal shelf 7 is covered with vinyl chloride without being exposed in the room 1, an electric field atmosphere is produced in the entire room 1.

In the prior art, an electric field or a magnetic field is applied to the received object to be cooled, such that the received object enters a supercooled state. Accordingly, a complicated apparatus for producing the electric field or the 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 the magnetic field.

Additionally, the apparatus for producing the electric field or the magnetic field should further include a safety device (e.g., an electric or magnetic field shielding structure, an interception device, etc.) for protecting the user from high power, when producing or intercepting the electric field or the magnetic field.

DISCLOSURE

Technical Problem

An 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 only by the 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 includes a handle to compensate for relatively weak thermal insulation in its front surface portion.

Technical Solution

According to an aspect of the present invention, there is provided a non-freezing storage unit, including: an outer casing with an open front surface; a drawer which can be pulled out through the open front surface of the outer casing; a sensor installed on the outer casing and/or the drawer; a heater installed in the outer casing; and an air layer formed at the front of the drawer to intercept the cool air, 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, the air layer is separated from a food storage space in the drawer by a protruding portion protruding from the front surface of the drawer.

Moreover, the protruding portion is formed in the shape of ‘┐’ to be bent from the top to bottom.

Further, the air layer is separated from the food storage space in the drawer by a protruding portion protruding from the bottom surface of the drawer.

Furthermore, the drawer is provided with a sign to prevent the food from being put in a space for defining the air layer.

Still furthermore, a thermal insulation material is filled in the inside of the outer casing.

Still furthermore, when the drawer is completely inserted into the outer casing, the bottom surface, the side surfaces and the rear surface of the drawer have a given interval from the outer casing.

Still furthermore, the drawer includes a bulkhead separating the air layer from the food storage space in the drawer.

Still furthermore, the bulkhead includes an opening portion for circulating the air in the air layer and the storage room.

Still furthermore, the air layer is separated from the food storage space in the drawer by a plurality of pins protruding from the bottom surface of the drawer.

Still furthermore, an opening portion is provided at the front of the bottom surface of the drawer, where the air layer has been formed, such that the air can be introduced from the lower portion of the drawer to the air layer.

Still furthermore, a rib is formed around the opening portion in the bottom surface of the drawer.

Advantageous Effects

According to the non-freezing storage unit provided by the present invention, the drawer can be completely pulled out of the outer casing, which improves convenience in use.

In addition, according to the non-freezing storage unit provided by the present invention, the air layer is formed at the front portion to insulate the front portion from the other parts of a refrigerator. This can compensate for a relatively weak thermal insulation effect in the front portion.

DESCRIPTION OF DRAWINGS

FIG. 1 is a view of an example of a conventional thawing and freshness-keeping apparatus.

FIG. 2 is a circuit view of the circuit configuration of a high voltage generator.

FIG. 3 is a view showing a process in which ice crystal nucleuses are formed in a liquid during the cooling.

FIG. 4 is a view showing a process of preventing the ice crystal nucleus formation, which is applied to an apparatus for supercooling according to the present invention.

FIG. 5 is a schematic configuration view of the apparatus for supercooling according to the present invention.

FIG. 6 is a graph showing a supercooled state of water in the apparatus for supercooling of FIG. 5.

FIG. 7 is an exploded perspective view of a non-freezing storage unit according to an embodiment of the present invention.

FIG. 8 is a perspective view of the non-freezing storage unit according to the embodiment of the present invention.

FIG. 9 is a sectional view of the non-freezing storage unit according to the embodiment of the present invention.

FIG. 10 is a view of a metal plate installed in a drawer of the non-freezing storage unit according to the embodiment of the present invention.

FIG. 11 is a view showing a state where the metal plate is installed in the drawer of the non-freezing storage unit according to the embodiment of the present invention.

FIG. 12 is a view showing a process in which the drawer of the non-freezing storage unit of the present invention is inserted into an outer casing.

FIG. 13 is a view showing a state where a contact point portion and a sensor installation portion of the non-freezing storage unit of the present invention are in contact with each other.

FIG. 14 is an exploded perspective view of a front portion of the drawer included in the non-freezing storage unit according to the embodiment of the present invention.

FIG. 15 is a view of a first example of an air layer structure included in the non-freezing storage unit according to the embodiment of the present invention.

FIG. 16 is a view of a second example of the air layer structure included in the non-freezing storage unit according to the embodiment of the present invention.

FIG. 17 is an exploded perspective view of a side casing provided in the non-freezing storage unit according to the embodiment of the present invention.

FIG. 18 is a view of an example in which the non-freezing storage unit according to the embodiment of the present invention is applied to a conventional refrigerator.

FIG. 19 is a side-sectional view of the example in which the non-freezing storage unit of the present invention is applied to the conventional refrigerator.

MODE FOR INVENTION

Hereinafter, the present invention will be described in detail with reference to the exemplary embodiments and the accompanying drawings.

FIG. 3 is a view showing a process in which ice crystal nucleuses are formed in a liquid during the cooling. As illustrated in FIG. 3, a container C containing a liquid L (or a received object) is cooled in a storing unit S with a cooling space therein.

For example, it is assumed that a cooling temperature of the cooling space is lowered from a normal temperature to a temperature below 0° C. (the phase transition temperature of water) or a temperature below the 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 of 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.

FIG. 4 is a view showing a process of preventing the ice crystal nucleus formation, which is applied to an apparatus for supercooling according to the present invention.

In FIG. 4, to prevent the freezing of the vapor W1 in the gas Lg, i.e., to continuously maintain the vapor W1 state, the energy is applied to at least the gas Lg or the surface Ls of the liquid L so that the temperature of the gas Lg or the surface Ls of the liquid L can be higher than a temperature of the maximum ice crystal formation zone of the liquid L, more preferably, the phase transition temperature of the liquid L. In addition, to prevent the freezing although the surface Ls of the liquid L is brought into contact with the inner wall of the container C, the temperature of the surface Ls of the liquid L is maintained higher than a temperature of the maximum ice crystal formation zone of the liquid L, more preferably, the phase transition temperature of the liquid L.

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 of 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 FIGS. 3 and 4. In the case of a received object containing a liquid, when the liquid in the received object is continuously supercooled, the received object can be kept fresh for an extended period of time. The received object can be maintained in a supercooled state at a temperature below the phase transition temperature via the above process. Here, the received object may include meat, vegetable, fruit and other food as well as the liquid.

Furthermore, the energy adopted in the present invention may be thermal energy, electric or magnetic energy, ultrasonic energy, light energy, and so on.

FIG. 5 is a schematic configuration view of the apparatus for supercooling according to the present invention.

The apparatus for supercooling of FIG. 5 includes a case Sr mounted in the storing unit S in which the cooling is performed and having a receiving space therein, a heat generation coil H1 mounted on the inside of the top surface of the case Sr and generating heat, a temperature sensor C1 sensing a temperature of an upper portion of the receiving space, a heat generation coil H2 mounted on the inside of the bottom surface of the case Sr and generating heat, and a temperature sensor C2 sensing a temperature of the lower portion of the receiving space or a temperature of a received object P. 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 heat generation 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 of 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 heat generation coils H1 and H2 in FIG. 5 are appropriately determined to supply the heat (or energy) to the received object P and the receiving space. The heat generation coils H1 and H2 may be inserted into the side surfaces of the case Sr.

FIG. 6 is a graph showing the supercooled state of water in the apparatus for supercooling of FIG. 5. The graph of FIG. 6 is a temperature graph when the liquid L is water and the principle of FIGS. 4 and 5 is applied thereto.

As illustrated in FIG. 6, a line I represents a curve of the cooling temperature of the cooling space, a line II represents a curve of the temperature of the gas Lg (air) on the surface of the water in the container C or the case Sr (or the temperature of the upper portion of the container C or the case Sr), and a line III represents a curve of the temperature of the lower portion of the container C or the case Sr. A temperature of an outer surface of the container C or the case Sr is substantially identical to the temperature of the water in the container C or the case Sr.

As shown, in a case where the cooling temperature is maintained at about −19° C. to −20° C. (see the 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 heat generation coils H1 and H2 supply heat.

Additionally, in FIG. 6, the energy is applied to the surface of the water or the gas Lg on the surface of the water before the temperature of the water reaches a temperature of the maximum ice crystal formation zone, more preferably, the phase transition temperature due to the cooling. Thus, the water stably enters and maintains the supercooled state.

FIG. 7 is an exploded perspective view of a non-freezing storage unit according to an embodiment of the present invention, FIG. 8 is a perspective view of the non-freezing storage unit according to the embodiment of the present invention, and FIG. 9 is a sectional view of the non-freezing storage unit according to the embodiment of the present invention.

The non-freezing storage unit according to the 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 a thermal 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 thermal insulation materials 210 and 310, respectively. It is thus possible to insulate the portions which are not sufficiently insulated by the thermal 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 thermal 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.

FIG. 10 is a view of a metal plate installed in the drawer of the non-freezing storage unit according to the embodiment of the present invention, and FIG. 11 is a view showing a state where the metal plate is installed in the drawer of the non-freezing storage unit according to the embodiment of the present invention. As described above, in the non-freezing storage unit according to the embodiment of the present invention, since the drawer 200 can be completely pulled out of the outer casing 100 and separated therefrom, the sensors 134 and 136 are not located in the drawer 200 but in the outer casing 200. There is a disadvantage in that the sensitivity of the sensors 134 and 136 sensing the temperature of the food stored in the drawer 200 may be reduced. To compensate for this, a metal plate 232 receiving a temperature change of the food distributed in the drawer 200, and contact point portions 234 and 236 transferring the temperature change of the metal plate 232 to the sensors 134 and 136 are provided in a basket 230 of the drawer 200. The contact point portions 234 and 236 are downwardly protruded from the bottom surface of the basket 230. When the drawer 200 is completely inserted into the outer casing 100, the sensor installation portions 134a and 136a and the contact point portions 234 and 236 are brought into contact without a gap, to thereby effectively transfer the temperature of the food to the sensors 134 and 136.

FIG. 12 is a view showing a process in which the drawer of the non-freezing storage unit of the present invention is inserted into the outer casing, and FIG. 13 is a view showing a state where the contact point portion and the sensor installation portion of the non-freezing storage unit of the present invention are in contact with each other. The drawer 200 included in the non-freezing storage unit according to the embodiment of the present invention includes the contact point portions 234 and 236 downwardly protruded from the bottom surface of the basket 230. When the contact point portions 234 and 236 are in contact with the sensor installation portions 134a and 136a without a gap, the sensors 134 and 136 can sense the temperature of the food better. However, while the drawer 200 is moved in the outer casing 100, if the contact point portions 234 and 236 continuously cause the friction in contact with the outer casing 100, problems occur such as the abrasion of the contact point portions 234 and 236 and the outer casing 100, the noise caused by the friction, and an excessive force to push and pull the drawer 200. Accordingly, it is preferable that the contact point portions 234 and 236 should maintain a given interval from the bottom surface of the outer casing 100 when the drawer 200 is moved in the outer casing 100, and should be brought into contact with the sensor installation portions 134a and 136a when the drawer 200 is completely inserted into the outer casing 100. For this purpose, guide portions 120 and 220 (see FIG. 12) guiding the movement position of the drawer 200 in the outer casing 100 are provided in the corresponding positions of the outer casing 100 and the drawer 200, respectively.

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.

FIG. 14 is an exploded perspective view of a front portion of the drawer included in the non-freezing storage unit according to the embodiment of the present invention. Referring to FIGS. 7 and 14, the front portion of the drawer 200 includes a front frame 240 defining the frame of the front portion of the drawer 200 and connected to the basket 230, a cover 250 covering the front of the front frame 240, a gasket 260 attached to the back of the front frame 240 and sealing up between the outer casing 100 and the drawer 200 when the drawer 200 is closed, a hook portion 272 fixing the outer casing 100 and the drawer 200 to be closely attached to each other when the drawer 200 is closed, an elastic member 274 applying an elastic force to the hook portion 272, and a grip portion 276 which can release a locked state of the hook portion 272. In addition, the thermal insulation material 210 of the drawer 200 mentioned above is filled in the front frame 240.

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 thermal 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 FIG. 12). Since the guide portions 120 and 220 (see FIG. 12) are inclined at the back, the drawer 200 receives a force in the rearward and downward directions due to the self weight. Therefore, when the drawer 200 is completely inserted, the gasket 260 is transformed between the drawer 200 and the outer casing 100 due to the weight of the drawer 200 to seal up the gap. Moreover, the non-freezing storage unit according to the embodiment of the present invention includes a hooked portion 172 and the hook portion 272 locking the outer casing 100 and the drawer 200 to enhance the sealing. To manipulate the hook portion 272, the grip portion 276 is located inside the handle 252 of the cover 250 and rotatably coupled to the front frame 240. When the user grips the grip portion 276 and holds the handle 252 with the grip portion 276, the grip portion 276 is rotated around coupling portions 276a located at both sides of the grip portion 276 and coupled to the cover 250 such that an upper part of the grip portion 276 pushes a lower part of the hook portion 272. The hook portion 272 is also rotated around coupling portions 272a coupled to the cover 250 such that an upper part of the hook portion 272 is lifted from the hooked portion 172 of the outer casing 100 and the coupling of the hook portion 272 and the hooked portion 172 is released. Thus, the user can pull the drawer 200 out of the outer casing 100. Here, the elastic member 274 with both ends fixed by the hook portion 272 and the cover 250 is provided so that the upper part of the hook portion 272 can be firmly fixed to the hooked portion 172 of the outer casing 100 in a normal situation, pressing the same. When the user grips the grip portion 276, the upper part of the hook portion 272 is lifted and the elastic member 274 is transformed, and when the user releases the grip portion 276, the upper part of the hook portion 272 is downwardly moved due to a restoring force of the elastic member 274. The outer casing 100 and the drawer 200 are fixed by the hook portion 272 and the hooked portion 172. This ensures the sealing between the outer casing 100 and the drawer 200.

FIG. 15 is a view of a first example of an air layer structure included in the non-freezing storage unit according to the embodiment of the present invention. As examined above, since the thermal insulation material 210 is filled in the front frame 240 at the front surface portion of the drawer 200, the thickness of the thermal insulation material 210 is smaller than that of the thermal insulation material 110 inserted into the outer casing 100, which degrades the thermal insulation effect. Accordingly, a protruding portion 280 is formed in a ‘┐’ shape to prevent food from being put in proximity to the front surface of the drawer 200. While the protruding portion 280 prevents food from being put in proximity to the front surface of the drawer 200, an air layer formed in the space where the food cannot be located due to the protruding portion 280 can operate as a thermal insulation material. Therefore, the protruding portion 280 has a relatively higher temperature than the front surface of the drawer 200. Even if food is brought into contact with the protruding portion 280, the food is prevented from being released from the supercooled state and frozen.

FIG. 16 is a view of a second example of the air layer structure included in the non-freezing storage unit according to the embodiment of the present invention. A plurality of pins 280′ protrude from the bottom surface of the basket 230 of the drawer 200 to prevent food from being put in proximity to the front portion of the drawer 200. In addition, a plurality of opening portions 290 are formed in the front portion of the basket 230 so as to effectively transfer heat of the lower heater 144 installed in the outer casing 100 to the front portion of the basket 230. The flow between the drawer 200 and the outer casing 100 heated by the lower heater 144 can be circulated by convection through the opening portions 290, and thus the temperature distribution in the non-freezing storage unit can be more uniform. Preferably, a rib 292 enclosing the opening portion 290 is formed around the plurality of opening portions 290 to prevent moisture of watery food or the like from being dropped into the outer casing 100 through the opening portions 290. Meanwhile, a bulkhead provided with a through hole to be able to produce a convection current, a plurality of pins protruding from the front surface of the drawer 200 at a given height, or the like can replace the plurality of pins 280′ protruding from the bottom surface of the basket 230, if they can define an air layer to prevent food from being put in the front portion of the basket 230 and the air layer can produce a convection current in the non-freezing storage unit. A sign preventing the user from putting food in the drawer 200 may be simply provided on the inner surface of the basket 230.

FIG. 17 is an exploded perspective view of the side casing provided in the non-freezing storage unit according to the embodiment of the present invention.

The thermal 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 FIG. 8) such that the temperature in the non-freezing storage unit ranges from about −5° C. to −8° C. The control panel (not shown) adjusts the heating values of the heaters 140 through the sensor 132 for sensing the temperature in the unit and the sensors 134 and 136 such that the temperature in the non-freezing storage unit exists in a desirable temperature range. For example, when the meat is stored in the non-freezing storage unit using the thin ice mode, it can be easily cut due to thin ices. Moreover, when the user selects the freezing function through the button 315b, the control panel (not shown) turns off all the heaters 140 and stores the food at the same temperature as that of the other region of the refrigerator without separate temperature control. Meanwhile, when the user selects the non-freezing function through the button 315c, the control panel (not shown) continuously senses the temperature in the non-freezing storage unit and the temperature of the food through the sensors 132, 134 and 136 and adjusts the heating values of the heaters 140 so that the temperature in the non-freezing storage unit can be 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 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 of 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 of the lower portion of the non-freezing storage unit is maintained at about −3° C. to −4° C.

FIG. 18 is a view showing an example in which the non-freezing storage unit according to the embodiment of the present invention is applied to the conventional refrigerator. The refrigerator 1000 is divided into a freezing chamber 1100 and a refrigerating chamber 1200. The non-freezing storage unit 2000 is installed in the freezing chamber 1100. When the non-freezing storage unit 2000 is installed in the freezing chamber 1100, the cool air cooling the freezing chamber 1100 cools the periphery of the non-freezing storage unit 2000, and thus the meat in the non-freezing storage unit 2000 is stored at a low temperature. Generally, the temperature in the freezing chamber 1100 ranges from −8° C. to −18° C., which is lower than a temperature for storing the meat in a non-frozen state. However, the control panel (not shown) adjusts the heating values of the heaters 140 (see FIG. 9) via a given algorithm using the sensor 132 for sensing the temperature and the sensors 134 and 136 so that the temperature in the non-freezing storage unit 2000 can be maintained at −2° C. to −4° C., thereby keeping the meat in the non-frozen state. The user may store the meat in a frozen state at the same temperature as that of the freezing chamber 1100 without turning on the heaters 140 (see FIG. 9).

FIG. 19 is a side-sectional view of the example in which the non-freezing storage unit of the present invention is applied to the conventional refrigerator. The freezing chamber 1100 and the refrigerating chamber 1200 are arranged on the left and right sides in the longitudinal direction in the refrigerator 1000, and the non-freezing storage unit 2000 may be installed between shelves of the freezing chamber 1100, or the topmost shelf or the bottommost shelf of the freezing chamber 1100. An evaporator 1300 is located on the rear surface of the freezing chamber 1100 to exchange heat with the ambient air to produce the cool air. The cool air is introduced into the freezing chamber 1100 to maintain the refrigerator 1000 at a low temperature.

The cool air heat-exchanged by the evaporator 1300 is introduced into the freezing chamber 1100 through a cool air vent 2420 via a duct 1600. When the freezing chamber 1100 is cooled by the cool air, as far as the heaters 140 (see FIG. 9) are not operated, the temperature in the non-freezing storage unit 2000 located in the freezing chamber 1100 is maintained to be the same as that of the freezing chamber 1100. When the heaters 140 are operated by the control of the control panel (not shown), the temperature in the non-freezing storage unit 2000 is maintained at −2° C. to −4° C. to store the meat in the non-frozen state. The non-freezing storage unit 2000 may be fixed to the freezing chamber 1100 such that only the drawer can be opened and closed in the forward direction, or the non-freezing storage unit 2000 itself may be separated from the freezing chamber 1100. When the non-freezing storage unit 2000 is manufactured to be separable from the freezing chamber 1100, preferably, terminals transmitting and receiving electricity are formed in the freezing chamber 1100 and the non-freezing storage unit 2000, respectively.

The present invention has been described in detail in connection with the exemplary embodiments and the accompanying drawings. However, the scope of the present invention is not limited thereto but is defined by the appended claims.

Claims

1. A non-freezing storage unit, comprising:

an outer casing with an open front surface;

a drawer which can be pulled out through the open front surface of the outer casing;

a sensor installed on the outer casing and/or the drawer;

a heater installed in the outer casing; and

an air layer formed at the front of the drawer to intercept the cool air,

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 the air layer is separated from a food storage space in the drawer by a protruding portion protruding from the front surface of the drawer.

3. The non-freezing storage unit of claim 2, wherein the protruding portion is formed in the shape of ‘┐’ to be bent from the top to bottom.

4. The non-freezing storage unit of claim 1, wherein the air layer is separated from a food storage space in the drawer by a protruding portion protruding from the bottom surface of the drawer.

5. The non-freezing storage unit of claim 1, wherein the drawer is provided with a sign to prevent the food from being put in a space for defining the air layer.

6. The non-freezing storage unit of claim 1, wherein a thermal insulation material is filled in the inside of the outer casing.

7. The non-freezing storage unit of claim 1, wherein, when the drawer is completely inserted into the outer casing, the bottom surface, the side surfaces and the rear surface of the drawer have a given interval from the outer casing.

8. The non-freezing storage unit of claim 1, wherein the drawer comprises a bulkhead separating the air layer from a food storage space in the drawer.

9. The non-freezing storage unit of claim 8, wherein the bulkhead comprises an opening portion for circulating the air in the air layer and the storage room.

10. The non-freezing storage unit of claim 1, wherein the air layer is separated from a food storage space in the drawer by a plurality of pins protruding from the bottom surface of the drawer.

11. The non-freezing storage unit of claim 1, wherein an opening portion is provided at the front of the bottom surface of the drawer, where the air layer has been formed, such that the air can be introduced from the lower portion of the drawer to the air layer.

12. The non-freezing storage unit of claim 11, wherein a rib is formed around the opening portion in the bottom surface of the drawer.