JP2008267789A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform supercooling freezing as a method of improving freezing quality of food by a method excluding quick freezing, with a simple constitution. <P>SOLUTION: This refrigerator for storing and refrigerating food by utilizing the cold air generated from a cooler 3, comprises a supercooling case 81 for keeping the stored food in a supercooling state free from freezing even under a temperature lower than its freezing point, at least for a specific time. The supercooling case 81 is composed of, for example, a lower case of upper and lower two-stage case disposed in a switching compartment 200 switchable into a plurality of temperature zones. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a frozen storage technique, and relates to a refrigerator (also referred to as a freezer refrigerator) using the technique.

It is generally known that when frozen food is thawed, the quality deteriorates compared to fresh food that has not been frozen. In the case of normal freezing, when a normal temperature food is placed in a space set at −18 ° C., the food temperature is cooled to the same temperature as the space after a certain period of time. And if the temperature is below the freezing point of food, it will freeze.
When the food is placed in a low temperature environment, it gradually cools from the surface and finally reaches the ambient temperature up to the central part. At this time, since the temperature of the surface first falls, the phenomenon that the surface begins to freeze first occurs. In such a case, the ice crystals formed on the surface of the food expands while drawing unfrozen water inside the food, so that a large needle-like crystal is formed toward the central portion. Since large acicular crystals destroy the original structure of food, it is very difficult to return the shape of the food when thawed to the state before freezing. Therefore, it can be said that how to make small ice crystals at the time of freezing and not destroying the original structure of food by ice crystals are the means to improve the freezing quality.
Recent needs for household refrigerators are gathered in “frozen” or “frozen storage” due to changes in eating habits and lifestyle. The frequency of use of freezer rooms is increasing due to diversification of frozen foods, increase in usage, preparation, and food stock. On the other hand, there is a high demand for food quality, and many attempts have been made to improve the quality of frozen preserved food.

  As a typical technique for solving such problems and realizing high-quality freezing, quick freezing is generally known. A typical high-quality freezing technique so far is quick freezing. A method often used for quick freezing quality assessment is a drip spill rate when thawing meat. The amount of drip spillage depends on the position and size of ice crystals when food is frozen. If the ice crystals are large, the cells are destroyed and the amount of drip spillage during thawing increases, leading to quality degradation. On the other hand, if the ice crystals are small, the shape of the cells is maintained, the amount of drip outflow during thawing is reduced, and the flavor of the food is retained.

The reason why the amount of drip outflow of the rapidly frozen food is small, that is, the reason why small ice crystals are formed inside the food is that the maximum ice crystal formation zone of -1 ° C to -5 ° C is passed quickly. Can be mentioned. Shortening the time in this temperature zone where ice crystal growth proceeds as much as possible suppresses the formation of large ice crystals.
Therefore, quick freezing can be said to be a means for suppressing the formation of large ice crystals inside the food.

  In the prior art, a quick freezing container having a metal plate on the bottom surface, and a cold air duct that discharges cold air for cooling food in the quick freezing container above the opening of the upper surface of the quick freezing container are provided. Some have attempted to perform quick freezing in a refrigerator by installing a quick freezing chamber having a thickness of 70 to 100 mm (see, for example, Patent Document 1).

  However, quick freezing has some problems. First, ice crystals tend to be small in quick freezing, but it cannot always be said that the ice crystals are really small up to the food center. When the food to be frozen becomes large to some extent, the surface directly exposed to cold air is thought to be rapidly cooled to form small ice crystals, but the temperature does not decrease at the center, staying in the maximum ice crystal formation zone, large ice crystals, or It is also conceivable that acicular ice crystals are formed. Next, since it is necessary to blow cryogenic cold air during quick freezing, it can be said that energy conservation is going backwards. In addition, in order to produce cryogenic cold, it is necessary to install a huge compressor with high performance, and there may be cost disadvantages.

As a new high-quality refrigeration technology that can avoid such problems of quick freezing, a supercooling refrigeration technology can be cited.
Supercooling means that when food is cooled under specific cooling conditions, it is not frozen at a temperature below the freezing point of the food. When food is stored in such a supercooled state, there is an advantage that cooling troubles such as protein denaturation and cell tissue damage caused by freezing can be avoided. In addition, when food that has been supercooled is forcibly stimulated to release the supercooled state, the food freezes rapidly, and the frozen state thus obtained passes through the supercooled state. It is reported that there is less damage to the cell tissue and the quality degradation is extremely small compared to the conventional quick freezing method (see, for example, Patent Document 2). Food that has been frozen through a supercooled state produces fine ice crystals that are granular, not needle-like, uniformly throughout the food, and therefore damage to cellular tissue is reduced.

In conventional supercooled freezing, a quick cooling process is performed in which foods (vegetables, fruits, meat, fish, etc.) close to the freezing point (freezing point) are cooled relatively quickly from room temperature, and then to the freezing point or below. There is a method of performing a slow cooling process of cooling at a slow cooling rate of 0.01 to 0.5 ° C./hour to create a supercooled state (see, for example, Patent Document 3).
However, when the supercooling state is slow and the supercooling state is too long, the food quality may be deteriorated due to oxidation or bacterial growth. Also, since the supercooling state is unstable, it is easy to release the supercooling before the minimum point temperature in the supercooling state reaches deep (low), and when the minimum point temperature is released as shallow (high) There is a problem that freezing with good freezing quality is not possible because there are few ice nuclei.

  In addition, when supercooled freezing is performed in a refrigerator in which several foods are mixed and stored at the same time, such as a refrigerator for home use, if it takes too much time from supercooling to freezing, There has been a problem that food that has already been frozen in an environment in which the temperature is maintained is left for a long time, and the quality of such frozen food is affected.

  Furthermore, the method of quick freezing to the vicinity of the freezing point and then shifting to slow cooling has the problem that it is very difficult to set the optimal transition point in a freezer that contains foods with different freezing points. It was.

  Moreover, in the said patent document 2, in the state which accommodated and sealed the food so that there was no dead space in a container, it exceeded -0.5 degreeC / h from the temperature higher than a freezing point to the temperature below a freezing point- A method is described in which the food (water, dairy product, strawberry) is brought into a supercooled state through a step of cooling at a cooling rate of 5.0 ° C./h or less.

  When such a method is used, it is possible to create a supercooled state at a faster cooling speed than before, but it takes time to seal the food.

  Another problem is that it is difficult to seal all foods that can be stored in the freezer.

  In addition, a static magnetic field is generated in the internal space of the freezer, and an electromagnetic wave having a predetermined frequency determined according to the magnetic field strength of the static magnetic field is continuously or intermittently applied to an object located in the static magnetic field. In addition, a method is described in which nuclear magnetic resonance is generated in hydrogen nuclei constituting water molecules contained in the object to lower the freezing temperature of water so that the freezing temperature is usually lower (see, for example, Patent Document 4). .

  However, creating a supercooled state by such a method results in a complicated and large apparatus, and the practicality for food is reduced. Moreover, since it costs too much about an apparatus, when it considers mounting in a household refrigerator, it is thought that practical use is difficult. Furthermore, in recent years, attention has been focused on health damage caused by electromagnetic waves, and it is necessary to pay sufficient attention to the influence on the human body in order to apply it to a device that can be easily opened and closed, such as a household refrigerator.

Japanese Patent Laying-Open No. 2005-83687 (pages 6-17, FIGS. 2 and 3) JP 2003-180314 A JP-A-8-252082 JP 2000-325062 A

  The present invention has been made to solve the above-described problems, and a first object is to allow freezing without impairing the quality of food, that is, to realize high-quality freezing with a simple configuration. To get a refrigerator.

  In addition, the second purpose is to reverse the concept that freezing at a stretch with cryogenic cold air, which has been common knowledge in conventional refrigeration methods, is a freezing method that does not impair the quality of food most, and at a higher cooling temperature than before. And it is providing the refrigerator which can exhibit the merit of both energy-saving property and high quality refrigeration by implement | achieving high quality refrigeration by the method of cooling by changing a cooling temperature in multiple steps.

  The refrigerator according to the present invention is a refrigerator that stores and stores food using the cold air generated by the cooler, and that stores the stored food in a supercooled state that does not freeze at a temperature below the freezing point for at least a certain time. A cooling chamber is provided. For this purpose, temperature control, a supercooling chamber structure, or a supercooling chamber case structure capable of reducing the direct blowing of cold air, equalizing the temperature, and changing the cooling temperature in a plurality of steps is adopted.

  The refrigerator of the present invention adopts a supercooling refrigeration function as a high quality refrigeration function instead of the conventional quick refrigeration function, so that it is possible to realize high quality refrigeration with less energy than conventional, that is, eco refrigeration. Has an effect.

  In addition, the refrigerator of the present invention reduces the direct blow of cold air into the space for supercooling, can equalize the temperature, and can change the cooling temperature in multiple steps. By adopting the cooling chamber structure or the supercooling chamber case structure, it is possible to realize supercooling and freezing of food with the structure and control of the refrigerator which is not greatly different from the conventional one.

Embodiment 1 FIG.
First, the supercooling will be described in detail. FIG. 1 is a graph showing temperature changes when water is frozen with no supercooling (a) and with supercooling (b). The vertical axis of the graph is the temperature, and the temperature increases as it goes upward. The horizontal axis is time, and the passage of time is shown in the direction of the arrow.
The supercooled state refers to a state in which the substance is not frozen by 100% despite being below the freezing point. Here, the freezing point refers to the temperature at which the substance begins to freeze. That is, the supercooled state is a state at which the temperature should start freezing but not frozen at all. For example, the freezing point of water is 0 ° C. This freezing point varies depending on the substance, and tends to be lower than 0 ° C. in foods having a high salt concentration and high sugar content.
The supercooling state and the freezing after the supercooling state will be described in more detail by taking water as an example. The supercooling state is a state of 100% water even when the freezing point falls below 0 ° C. when the water is cooled. Say. The water that has entered the supercooled state can eventually be frozen and turned into ice, but this requires some kind of stimulation. This stimulus may be temperature or physical. In this way, freezing can be started by stimulation, but the time from the supercooling state to the start of freezing is in units of several seconds and is instantaneous. However, the proportion of water that freezes instantaneously at the start of freezing is several percent of the total, and it takes further cooling time before it becomes 100 percent ice.

Here, the difference between normal freezing and supercooled freezing will be described in comparison. First, the main difference between normal freezing and supercooling freezing is whether or not a supercooled state is entered. In the case of normal freezing, when the freezing point is passed, freezing starts without entering the supercooling state.
Another major difference between normal freezing and supercooling freezing is the state at the start of freezing. Here, the phenomenon that occurs at the start of freezing will be explained using water in a plastic bottle as an example. In normal freezing, when freezing starts, the water near the surface of the plastic bottle begins to freeze. It becomes a state where thin ice is applied to the part, then the ice spreads toward the inside, and finally the whole freezes. Ice growth occurs mainly around ice nuclei in which water molecules form clusters of a certain size or more, and ice nucleation occurs at the start of freezing. Therefore, in the case of normal freezing, it can be said that ice nuclei are formed on the surface, and the ice grows from there to the portion that is in the water state.
On the other hand, in the case of supercooled freezing, ice nuclei are uniformly formed in the entire PET bottle when freezing starts. And because the ice grows in every part of the PET bottle, both inside and on the surface, the ice never grows in a certain direction.
The difference between normal freezing and freezing after completion of freezing is due to the difference in the cooling process. In normal freezing, large acicular ice crystals from the surface to the inside are formed, whereas in freezing freezing. Produces uniformly small granular ice crystals on the surface and inside.
Further, in the case of quick freezing, the state at the start of freezing and after the completion of freezing is the same as in the case of normal freezing in that it is quickly frozen by applying cold air to the surface. First, the temperature of the surface suddenly drops, so it begins to freeze from the surface. However, the difference from normal freezing is that the cooling rate to the inside increases, so that ice nuclei are more likely to form inside than normal freezing, and no larger ice crystals are formed than during normal freezing.
When considering food freezing, the size and shape of ice crystals after freezing has a significant effect on the quality of food when thawed. Since food is mostly composed of cells, proteins, carbohydrates, etc., once its structure is destroyed by ice crystals, it often cannot be completely restored. Therefore, it can be said that freezing with good quality has been achieved if the size and shape of the ice crystals formed upon freezing does not destroy the original structure of the food.

Next, the merit and novelty of freezing food by supercooled freezing will be described. The greatest merit of freezing food with supercooled freezing is that it can be frozen with good quality. As described above, in freezing after a supercooled state, the inside of the food is sufficiently cooled in the process of being supercooled, so that ice nuclei are uniformly formed throughout the food, and small granular ice is formed. Grows into crystals. In addition, the larger the difference between the minimum temperature reached in the supercooled state and the freezing point (the difference between the points A and B in FIG. 1B), the larger the number of ice nuclei formed at the start of freezing. , Become finer ice crystals. Therefore, if the supercooling sufficiently occurs (the lower the temperature reached in the supercooled state is), it is possible to maintain a state closer to that before freezing after freezing → thawing.
When considering the cooling of food and the size and shape of ice crystals, it has been conventionally performed to consider the passage time in the temperature zone of -1 ° C to -5 ° C, which is the maximum ice crystal formation zone. The idea is that ice crystals become smaller if they pass through this maximum ice crystal formation zone in a short time.
In the case of supercooled refrigeration, it takes a long time to stay in the supercooled state in the temperature range (around -1 ° C to -10 ° C) including this maximum ice crystal formation zone. However, the supercooled state is a state that is not frozen. Therefore, in the supercooled state, the ice crystals after freezing do not become large even if this temperature zone passage time is long, and it is possible to make fine ice crystals. It is a completely new refrigeration method in that small ice crystals are formed by freezing in a temperature range around this including the maximum ice crystal temperature range, and freezing is performed with good quality. In addition, freezing starts when the supercooling state is released, and it completely freezes through a phase change state in which the temperature does not change, but if it has passed through the supercooling state, it will reach the maximum ice crystal formation zone in the subsequent freezing process. Even if it stays for a long time, it has been confirmed that ice crystals do not enlarge. Therefore, it can be said that this is also a novel refrigeration method.
If it has undergone supercooling, even if the subsequent freezing process takes a long time, there is almost no effect on the ice crystal state, but if it freezes rapidly when entering the freezing process, the possibility that the ice crystals will enlarge It can be further reduced, and it is possible to avoid food quality deterioration factors other than ice crystals.
In addition, up to now, only the merit in the case where the food that has entered the supercooled state is released after being supercooled and frozen is described, but it is not always necessary to freeze the food that has entered the supercooled state. The merit of maintaining the supercooled state is that the ice crystals are not formed at all, even though it is stored at a temperature below the freezing temperature, that is, at a temperature that would normally freeze. For this reason, the food structure is not affected by ice crystals at all while being stored at a low temperature. Although it is generally known that storage at a lower temperature is effective for preserving freshness in that various chemical changes in food can be suppressed, both this low-temperature storage and unfrozen It can be said that it is a storage method that can achieve the merits of. There is no need to thaw the food. However, being in an unfrozen state also has a disadvantage. The fact that moisture in food is not frozen means that it can be used for bacterial growth and various chemical changes. Therefore, care must be taken in this regard rather than frozen ones.

Next, the present invention will be described in detail based on the embodiment. The refrigerator according to the embodiment of the present invention maintains a stable temperature environment necessary for stably realizing supercooling, and the temperature, wind speed, air volume, timing, etc. of the cold air directly applied to the food A control mechanism, a case structure, a device or a control mechanism for determining completion of supercooling necessary for reliably realizing supercooling cancellation, and a device or control mechanism for providing stimulation necessary for supercooling cancellation . It also has a cooling and storage function for maintaining high-quality freezing after the release of supercooling.
First, the supercooling conditions in the supercooling chamber (same as the supercooling space) of the refrigerator of the present invention will be described. The most important point when setting the supercooling condition is the difference between the freezing point and the minimum point of reaching the core temperature of the food to be cooled (the temperature reached in the supercooled state).
If the cooling rate is too fast, the whole food is cooled in a non-uniform state, so that a frozen part (a large difference between the surface temperature of the food and the core temperature) and an unfrozen part are formed. Since ice crystals grow around ice nuclei, if a portion of the food freezes, it grows while taking in moisture from the unfrozen portion. As a result, large acicular ice crystals are formed. Needle-shaped ice crystals or large ice crystals generated between cells cause water outflow and cell destruction in the cells and cause drip outflow when the food is thawed. As a result, the original taste of the food is reduced or the texture is deteriorated.
On the other hand, if the cooling rate is too slow, there is no problem in maintaining the supercooled state, but the unfrozen state becomes longer, which causes a problem that food quality deteriorates due to bacterial propagation, oxidation promotion, and the like.
In other words, it is cooled so that the difference between the surface temperature and the core temperature becomes small until the freezing point, and when the temperature reaches the freezing point or lower (supercooled state), the cooling rate is increased and the core temperature reaches the lowest point. The supercooling is released so that the unfrozen state does not become longer. In this way, the temperature control and the temperature zone until the food is released from the supercooling to the freezing point, to the supercooling state below the freezing point, and completely frozen are performed continuously or stepwise. In order to solve such a problem, there is a method of adding an antibacterial function to the supercooling space. Examples of the antibacterial function include a method using ultraviolet rays and ozone. However, there is also a problem that it is costly to add antibacterial functions.

  Considering the above, it is necessary to limit the cooling rate to some extent. For example, in foods such as pudding and yogurt, the core temperature is set to a cooling rate in the range of 300 ° C./h to 0.35 ° C./h, preferably around 3.5 ° C./h to create a supercooled state. The cooling rate is such that the core temperature is within a temperature range from the freezing point to 20 ° C. lower than the freezing point, preferably from the freezing point to −10 ° C.

Further, the supercooled state needs to be maintained for a certain time, for example, 5 seconds or more. This is to make the supercooling temperature deeper. In other words, lowering the temperature at which the food reaches in the supercooled state.
The reason why the subcooling temperature should be deep may be as follows. As the supercooling temperature becomes deeper, the amount of sensible heat energy stored in the supercooling increases. As a result, the energy of the instantaneous latent heat change used when the supercooling is released increases. Many ice nuclei are generated in the food at the same time when the cooling is released, and ice crystals grow using the ice nuclei as nuclei, so that a large number of small ice grains can be formed uniformly in the food, affecting the cells. It can be said that it becomes smaller.

  Further, the difference from the surface temperature when the core temperature reaches the temperature at which supercooling can be released is preferably in the range of 0 ° C. to 10 ° C., preferably within 5 ° C. The difference between the surface temperature and the core temperature is about 1 ° C. if the beef leg meat has a thickness of 15 mm and 150 g.

  The range about the above cooling conditions can be said similarly about foodstuffs, such as meat, fish, vegetables, and fruits.

  In the setting of the supercooling condition, the second thing is about the fluctuation of the air temperature in the supercooling space (temperature difference due to time).

  The width of the air temperature fluctuation is preferably within 5 ° C. However, if the temperature is within 15 ° C., the quality may deteriorate somewhat, but it is possible to create a supercooled state. The reason why food quality deteriorates when the air temperature fluctuation range is large is that ice crystals grow slightly larger by repeated freezing and thawing. As another means for reducing the air temperature fluctuation range, the fluctuation range predetermined in the microcomputer or the like may be reduced in order to control the device based on a detection value of a thermistor (not shown). It is preferably within 4K (4 ° C), more preferably within 1K (1 ° C).

As the third supercooling condition, air temperature unevenness (temperature difference depending on location) in the supercooling space may be mentioned.
The air temperature unevenness may be within 15 ° C., but is preferably within 5 ° C. The problem of air temperature unevenness being too large is that partial freezing occurs when trying to cool large foods.

Here, the temperature setting reference | standard of supercooling freezing is described. Examples of the temperature zone that satisfies the cooling rate as described above and has a high probability of occurrence of supercooling include −3 ° C. to −10 ° C. In this temperature range, the freezing point of most foods that are thought to be frozen is included, so that it is possible to freeze them stably after supercooling. In addition, the food storage period in such a temperature range is about two weeks. For example, even if the food purchased by bulk purchase on the weekend cannot be used due to a change in schedule or the like, it can be stored with confidence until the next week. Moreover, if it preserve | saves after freezing in this temperature range, since it can cut with a kitchen knife etc., without thawing | decompression, the effort of cooking can be saved.
When desserts such as yogurt and pudding are frozen by supercooled freezing, very fine ice crystals are formed, so that a new texture different from that of normal freezing and refrigeration can be obtained. In addition, when milk or juice is supercooled and frozen, a new menu unique to fine ice crystals may be possible, such as a sherbet with a texture different from normal freezing.

FIG. 2 is a diagram showing the state of the meat tissue when the meat is frozen by normal quick freezing and supercooling freezing, and when the frozen meat is once thawed. Thus, it is known that if the ice crystals formed inside when meat or fish are frozen are large, the cells are destroyed and the amount of drip after thawing increases. Therefore, when comparing the amount of drip of supercooled frozen and normal frozen beef tuna and tuna, the tendency of supercooled frozen to be reduced to less than half that of normal frozen is seen.
Potatoes, such as potatoes, have traditionally been considered unfit for freezing. When making curry, etc., it is a common practice in ordinary households to store it frozen and reheat after the next day, but at that time, only potatoes are removed or crushed It was said that freezing was the common sense for freezing curry deliciously. This is because when potatoes are frozen and thawed, they become scary and the texture becomes worse. However, it is known from experimental results that when the curry is frozen by supercooled freezing, the texture of the potato is almost the same as that before freezing after thawing, and it does not become a scary texture or a sticky texture. Starch, which is the main ingredient of potato, is composed of amylose and amylopectin, but it was conventional freezing that destroyed the three-dimensional structure by the growth of ice crystals. Once a structure has been destroyed, it will not return to its original state after being decompressed. On the other hand, since the ice crystals produced by supercooled freezing are very fine, the three-dimensional structure of starch is hardly deformed during freezing, and the original three-dimensional structure can be maintained even after thawing. Therefore, it is considered that the texture of potatoes thawed after supercooled freezing does not deteriorate. Such a principle may also apply to other foods that have been considered unsuitable for freezing, so using supercooled freezing allows foods that were previously considered unsuitable for freezing to be frozen. Is also suggested.
Thus, it has been found that when foods are frozen through a cooled state, fine ice crystals are formed, so that the original food structure such as cells and proteins can be maintained without change. Therefore, there is a possibility that the quality will not be extremely deteriorated as in the conventional freezing even if the freeze-thaw is repeated, for example, the frozen-thawed food is frozen again.
The above describes the merits of utilization in ordinary households, but it can be said that supercooled refrigeration can be used effectively in food processing. The result is that the fineness of ice crystals produced by supercooled freezing is superior to that of -60 ° C, and it can be said that it can be replaced with a commercial freezer in terms of realizing high-quality freezing. In addition, there is an advantage in that energy saving is high because it is not necessary to create cryogenic cold air using a large amount of energy for business use.

  Next, the structure of the supercooling space for realizing the supercooling state, the method for determining the supercooling state release timing, and the supercooling release method will be described with reference to the drawings. In addition, in each following figure, the same code | symbol shall represent the same thing or an equivalent.

Embodiment 1 FIG.
A refrigerator according to Embodiment 1 of the present invention in which frozen storage is performed through a supercooled state will be described in detail. FIG. 3 is a cross-sectional view of refrigerator 1 according to Embodiment 1 of the present invention. The food storage room of the refrigerator 1 is provided with a refrigeration room 100 provided with an open / close door at the top, and refrigeration, vegetables, chilled, soft refrigeration (-7 Switching room 200 having a drawer door that can be switched to a temperature range such as ° C.), an ice making room 500 having a drawer door in parallel with the switching chamber 200, a freezing room 300 having a drawer door arranged at the bottom, and a freezing room The vegetable room 400 is provided with a drawer door between 300, the switching room 200 and the ice making room 500. On the door surface of the refrigerator 100, there is provided an operation panel 5 composed of an operation switch for adjusting the temperature and setting of each room and a liquid crystal for displaying the temperature of each room at that time.

  A compressor 10 and a cooler 3 constituting a refrigeration cycle are arranged on the back side of the refrigerator 1, and a fan 2 for blowing cold air cooled by the cooler 3 to the refrigerator compartment 100 and the switching chamber 200, An air passage 4 for introducing the cold air cooled by the cooler 3 into the refrigerator compartment 100 is provided.

  A storage case 201 is installed in the switching chamber 200, a storage case 301 is installed in the freezer compartment 300, and a storage case 401 is installed in the vegetable compartment 400, and food can be stored in these cases. .

  FIG. 4 is a schematic side cross-sectional view of the refrigerator showing the air path configuration of the refrigerator according to Embodiment 1 of the present invention. A part of the cool air cooled by the cooler 3 is blown into the freezer compartment 300. The remaining cold air is blown into the switching chamber 200 through the air passage 4. A part of the cold air passing through the air passage 4 is further blown into the upper refrigerator compartment 100 to cool the refrigerator compartment 100. The vegetable room 400 is cooled by circulating the return cold air from the refrigerating room 100 through the refrigerating room return path 6, and the air passing through the vegetable room 400 returns to the cooler 3 through the vegetable room return path 7.

FIG. 5 is a side sectional view of switching chamber 200 according to Embodiment 1 of the present invention. The switching chamber 200 located between the refrigerator compartment 100 and the vegetable compartment 400 is provided with a switching chamber air passage 41 that guides cold air from the air passage 4 to the switching chamber 200 via a damper (switching chamber damper) 46. . And the switching room back surface upper side blower outlet 42 at the upper left of the back as viewed from the front side of the refrigerator, and the switching room ceiling surface outlet port 43 on the near side of the ceiling surface are provided as cold air outlets. Further, the switching chamber 200 is provided with a switching chamber rear surface suction port 44 at the lower right of the rear surface and a switching chamber bottom surface suction port 45 at the bottom surface.
Switching room 200 is switched to six temperature zones such as refrigeration (about 3 ° C), chilled (about 0 ° C), soft refrigeration (about -5, -7, -9 ° C), and refrigeration (about -17 ° C). The temperature can be switched by the liquid crystal panel 5 installed on the door of the refrigerator compartment 100. The temperature of the switching chamber 200 is controlled by a set temperature of a thermistor (not shown) and its detected value.

Next, a structure in which a supercooling chamber is installed in the switching chamber 200 will be described. FIG. 6 is a structural diagram of a supercooling case according to Embodiment 1 of the present invention. In FIG. 6, the switching chamber storage case 201 shown in FIG. 5 is divided into two upper and lower stages to form a two-stage slide case, the upper case 80 as a normal switching case, and the lower case 81 as a supercooling space. It is a supercooling case. When the switching chamber 200 is pulled out, the switching case 80 and the supercooling case 81 are pulled out simultaneously. When the supercooling case 81 is used, the stored item can be taken out from the supercooling case 81 by sliding the switching case 80 to the back.
According to this structure, when only the switching case 80 is used, the upper switching case 80 prevents the airflow from directly flowing into the lower supercooling case 81, so that the air temperature of the supercooling case 81 is increased. Suppress. Further, during normal cooling, the upper part of the supercooling case 81 is covered by the switching case 80, and the structure is such that cold air does not enter directly. Therefore, the slow cooling necessary for making supercooling is possible.

  Further, a substance having a large heat capacity (for example, injecting a metal plate or a cold storage material in a double structure of the case) that can suppress a change in air temperature may be installed on the bottom surface 82 of the switching case 80. In this way, since the bottom surface 82 corresponds to the upper part of the supercooling case 81, the effect of suppressing the air temperature fluctuation in the supercooling case 81 can be obtained during normal use of the refrigerator including opening and closing of the door.

There may be a space of about 1 mm to 20 mm between the switching case 80 and the supercooling case 81. In that case, the effect of cooling the supercooling case 81 by flowing cool air into the supercooling case 81 at the time of supercooling, and canceling the supercooling. In some cases, the flow of cold air is improved, so that the effect can be efficiently obtained. Even during supercooling, the blown out cold does not enter directly, and there is no problem as long as the airflow is at a natural convection level. Even if cold air is directly flowed in, the same effect can be obtained by reducing the wind speed or increasing the cold air temperature. In the case of a structure in which there is a gap between the switching case 80 and the supercooling case 81, a wheel is attached to the bottom surface of the switching case 80 and the guide is installed on the supercooling case 81. It is conceivable that a groove is formed on the bottom surface of the substrate, and a support column installed on the upper portion of the supercooling case 81 is fitted and slid. A rail for sliding only the switching case 80 back and forth may be installed on the wall surface.
Even when there is no gap between the switching case 80 and the supercooling case 81, an appropriate cooling performance can be obtained. When there is no gap, the range of air temperature fluctuation during normal cooling can be kept small.

Furthermore, as shown in FIG. 6, by dividing the case with a height into two stages, it is possible to obtain an effect that the arrangement in the case is improved and the usability is improved. Also, by making the underside of the two-stage case a supercooling space, the effect of improving the cooling performance of the supercooling space from the characteristic that cold air accumulates downward, the upper case directly flows into the lower case. The effect of suppressing the air temperature fluctuation in the case of playing a role of suppressing air is also obtained.
As shown in FIG. 7, the structure in which the lower side of the two-stage case has a supercooling space is provided with a step on the bottom so that the depth of the upper case is different between the front side and the rear side. It is good also as a structure arrange | positioned corresponding to a space. In FIG. 7, the upper case is the switching case 83 and the lower case is the supercooling case 84. The structure of FIG. 7 has an advantage that tall food can be stored on the back side of the switching case 83 and small items can be stored on the door side.
Further, as a structure in which the lower side of the two-stage case is a supercooling space, a structure as shown in FIG. 8 may be used. In FIG. 8, the upper case is the switching case 85 and the lower case is the supercooling case 86. The depths of the switching case 85 and the supercooling case 86 are not necessarily the same, and a part of the gap may be opened. Further, the switching case 85 can be a fitting type, and a sliding type can be adopted in which the case is pushed inward to take out food in the supercooling case 86. In the structure of FIG. 8, since a supercooling space can be formed only by adding the upper case, there is an advantage that the cost can be reduced when changing.

  Next, the supercooling control of the supercooling chamber (supercooling case) will be described. Here, the supercooling release timing is determined based on the accumulated time from the start of supercooling, and the supercooling release is performed by changing the air temperature around the food to the low temperature side. FIG. 9 is a timing chart showing the control of the refrigerator at this time. In order to supercool the food stored in the supercooling case, until the core temperature of the food in the supercooling case exceeds the freezing point and reaches a supercooled state (stage 1), the compressor 10, the fan 2, the damper 46, etc. However, it operates so that the room (here switching room 200) with a supercooling case may be made into the air temperature selected in the range of -2 ° C--20 ° C, for example. The compressor 10 and the fan 2 may be controlled by the temperature of another room, and the temperature may be controlled only by opening / closing the damper 46. In this stage 1, the set temperature of a thermistor (not shown) for setting the temperature of the switching chamber 200 is the same as that in the normal state (displayed as “Tset” in FIG. 9). When the supercooling can be released (refers to a state where the food temperature is supercooled to a temperature 3 ° C lower than the freezing point) (after holding the supercooled state for at least 5 seconds) (stage 2), After the cooling is released, until the whole food is completely frozen (stage 3), the set temperature of the thermistor may be the normal temperature setting (Tset), but the set temperature is lowered ("Tset-down" in FIG. 9). And the temperature of the switching chamber 200 may be shifted down. In that case, the certainty of cancellation of supercooling is increased, and the freezing quality is improved because the cooling rate after the cancellation is fast. In addition, the freezing quality is further improved by rapid cooling so that the temperature in the supercooling case is lowered to −20 ° C. or lower as in normal quick freezing and freezing at once. With regard to the storage temperature setting after the food is completely frozen (Stage 4), if the temperature is set to a high temperature side such as −15 ° C. or higher, the energy saving is enhanced, and even if stored frozen at −5 to −10 ° C., from the refrigerator. Easy to use because it is cut with a knife immediately after taking it out. Further, when the temperature is set to a low temperature such as −15 ° C. or lower, the storage stability is enhanced.

  The above control operation of the refrigerator 1 is summarized as shown in the flowchart of FIG. When the supercooling button provided on the liquid crystal panel 5 in FIG. 3 is pressed, the supercooling time integration starts (step 1). Here, the time required to reach the supercooling temperature from room temperature is determined in advance in the range of 5 minutes to 72 hours, preferably in the range of 1 to 24 hours. The control automatically changes the temperature to the low temperature side (step 3). When a thermistor (not shown) detects a temperature rise in actual use, such as opening and closing a door, only the time below a predetermined temperature is accumulated. If it is determined that the accumulated time of stage 2 and stage 3 shown in FIG. 9 has reached a predetermined time (step 4), the set temperature of the thermistor and the speed of compressor 10 and fan 2 are returned to normal values (step 5). .

  Next, an embodiment in the case where the two-stage case is not used will be described. FIG. 11 is a side sectional view of switching chamber 200 according to Embodiment 1 of the present invention. About the same code | symbol as FIG. 5, it is the same structure. A partition wall 41 a that adjusts the distribution of cool air to the switching chamber rear upper outlet 42 and the switching chamber ceiling outlet 43 on the near side of the ceiling is arranged in the switching chamber air passage 41. Distribute cold air. 95 is an apparatus for measuring the surface temperature of food to be frozen by supercooling, for example, an infrared sensor. It is set on the ceiling surface 96 of the switching chamber 200 so that the surface temperature of the food can be detected. The surface temperature measuring device 95 is installed behind the ceiling surface 96 when the air outlet 43 is on the near side of the ceiling surface 96, for example, as a position not affected by the cold air from the ceiling surface outlet 43. On the other hand, the cold air from the rear outlet 44 is more strongly stimulated by the food than the outlet 43, so that it is installed on the ceiling surface 96 at the upper back to make it easier to detect the state of the food due to the cold air from the outlet 44. Yes.

Next, the supercooling control of the supercooling chamber (supercooling case) will be described. In order to supercool the food stored in the supercooling case, the surface temperature of the food should be set so that the surface temperature of the food is too low to start freezing before the core temperature of the food in the supercooling case reaches the freezing point. While detecting by the surface temperature measuring device 95, cooling is performed so as to reduce the difference between the core temperature and the surface temperature. For example, the opening / closing angle of the damper 46 is half-opened to the position of the partition wall 41a as shown in FIG. 12, and the wind speed of the cool air flowing into the supercooling case is lowered by increasing the cool air distribution to the outlet 43. Moreover, the cold air temperature rises by extending the distance passing through the air passage 41, the cold air temperature from the air outlet 43 becomes higher than the cold air flowing in from the air outlet 42 close to the damper 46, and the food surface is rapidly cooled. There is no effect. The switching room set temperature at that time is set higher than the normal set temperature.
Cool as described above until the core temperature reaches the freezing point. When the core temperature reaches the freezing point, cool rapidly so as to lower the lowest point of the food temperature. This is because the temperature below the freezing point is in an unstable state, and if the temperature of the food is slowly lowered, there is a possibility that the temperature reached in the supercooled state is released while the temperature is high. Therefore, when the temperature of the surface temperature measuring device 95 reaches a temperature at which it can be determined that the freezing point has been reached, increase the FAN rotation speed to increase the amount of cool air flowing into the supercooling case, or open the damper 46 fully. (The state of the damper 46 in FIG. 11) Temperature control is performed so as to increase the cold air inflow amount and lower the minimum temperature. At that time, the switching chamber set temperature is the same as the temperature setting cooled to the freezing point or the set temperature is lowered.
Next, when the food is released from supercooling, the temperature of the surface temperature measuring device 95 rises. This is because the food temperature rises to the freezing point when the food is released from the supercooled state, and the ice nuclei in the food by the thermal energy of the difference between the freezing point and the supercooling arrival temperature (heat energy for the temperature rise). This is due to the phenomenon that generates In response to the determination, cool air is introduced into the supercooling chamber and the temperature is controlled so that it is completely frozen. The damper 46 is fully opened and the FAN rotation speed and the compressor rotation speed are increased so that cooler cold air can flow in. At that time, the switching room set temperature is set lower than the normal temperature.
In this way, the setting control is changed continuously or step by step in each stage from the freezing point to the supercooling minimum achievement point temperature, the supercooling release, and the complete freezing to the freezing point. For example, control the cool air temperature, cool air flow rate, and cool air speed to the supercooling case to ensure that it is in a supercooled state, lower the minimum supercooling temperature, cancel supercooling, and increase the freezing speed after release to improve the quality. Realize good freezing.
On the other hand, if the temperature of the surface temperature measuring device 95 does not drop from the freezing point even after a certain period of time, the food does not overcool (supercooling failure), phase changes from the freezing point, and enters the frozen state. The temperature is controlled so that it can be frozen as quickly as the temperature control after canceling the supercooling, so that the frozen quality of the food can be maintained as much as possible, even if it is not frozen through the supercooled state. Allow ice crystals to form.
For temperature control without failure, for example, in the case of meat, the temperature is controlled at -1 ° C, which is the freezing point, and the food is uniformly cooled to the freezing point of -1 ° C to the core temperature. Next, the temperature setting can be controlled to about -4 ° C to -7 ° C, and the supercooling attainment temperature is lowered. The supercooling minimum attainment temperature does not fall below the cooling temperature, so it is -3 ° C from the freezing point. When it is desired to make it below, it is necessary to cool at a temperature of -4 ° C or lower. However, if the temperature is too low, the overcooling is released without the lowest temperature being lowered, so -7 ° C is set. Regarding the supercooling release, when the lowest supercooling point reaches −3 ° C. or lower than the freezing point (the same effect as when the supercooling state is set for 5 seconds or more), the control for releasing the supercooling is performed and released. After the supercooling is released, the food is quickly frozen by rapid cooling control. If the food is already stored and stored so that it can be cut easily with a kitchen knife (stored at -5 to -10 ° C), the food temperature should be set to -10 ° C so that the already stored food will not be cut even during rapid cooling. It is desirable to control the temperature so as not to decrease below. If it is a freezing temperature zone, it is not necessary, and it is cooled rapidly at a lower temperature.
Even in environments where the wind speed is low, such as natural convection, the supercooled state and the minimum supercooling temperature can be achieved by stepwise temperature control, but the same effect can be obtained by controlling the wind speed and cold air temperature. For rapid cooling and rapid cooling control when the switching room is used in a refrigeration setting, cooling speed cannot be obtained by natural convection, but rapid cooling is possible when direct cooling air is introduced as in this example, so it can be used more widely. Is possible.
In the above embodiment, a lid or the like is not installed at the upper opening of the supercooling case, but the same effect can be obtained by controlling the amount of cool air and the speed of the cool air with the lid. At that time, the lid need not completely cover the upper opening, and may be in a range in which the amount of cold air and the speed of the cold air can be controlled.

Next, a case where the upper case of the switching case 201 configured in two upper and lower stages is used as a supercooling case will be described.
13 is a side sectional view of switching chamber 200 corresponding to FIG. 5 in the first embodiment of the present invention. As shown in FIG. 13, the upper case of the switching case 201 configured in two upper and lower stages is used as the supercooling case 40. The supercooling case 40 is installed behind the switching room ceiling surface outlet 43 and has a structure that can be pulled out in a sliding manner. According to this structure, the inside of the supercooling case 40 and the food stored therein are not directly exposed to the cold air from the switching room ceiling surface outlet 43, so that the temperature can be maintained in a stable state.

  FIG. 14 is a top view of the duct 50 connected to the switching room ceiling surface outlet 43. In order to cool the supercooling case 40 better, a structure may be adopted in which a hole 51 is formed in the middle of the duct 50 so that the cold air flowing through the duct 50 is naturally dropped.

  When the supercooling case of FIG. 13 is used, the switching case 201 is pulled out, and the independent supercooling case 40 is pulled out. Since the supercooling case 40 is pulled out only at the time of use, there is an advantage that the temperature of the supercooling case 40 is difficult to rise when the switching chamber 200 is used. Further, installing the supercooling case 40 above the switching chamber 200 has an advantage that a new case can be added without changing the size of the conventional switching case.

Next, the structure of the supercooling case will be described.
FIG. 15 is a structural diagram of a supercooling case according to Embodiment 1 of the present invention. Here, the upper part of the switching case 201 provided in the switching chamber 200 is covered with a lid 60, and the entire switching case 201 is used as a supercooling case. FIG. 15 is an example in which the entire switching case 201 is covered with a lid 60 and the whole forms a supercooling case. The switching case 201 may be provided with a partition in the vertical direction or the horizontal direction, and only a part of the partition is covered with the lid 60, and only the part covered with the lid 60 is a supercooling case. . Since the cool air is not directly blown into the space where the cover 60 is provided and is a supercooled case, the inside of the case is completely indirectly cooled. Moreover, there is almost no temperature fluctuation in the supercooling case formed in this way, and it can be realized at the lowest cost.
Note that the case without the lid 60 is referred to as a supercooled case by using radiation cooling by cooling the wall without blowing air into the case, for example, by cooling the wall by circulating cold air or refrigerant inside the wall. It is also possible to do.

Next, a structure in which a fan is provided in the switching chamber will be described.
FIG. 16 is a side sectional view of switching chamber 200 corresponding to FIG. 5 in the first embodiment of the present invention. As shown in FIG. 16, in the present embodiment, a fan (switching chamber fan) 70 is provided on the upper portion of the switching chamber 200. According to this configuration, the air in the switching chamber 200 can be slowly stirred by the action of the fan 70, so that the air temperature can be kept uniform without increasing the cooling rate. Large food may be put into the supercooling case 40, but with this configuration, the cooling unevenness of the whole food can be eliminated in such a case, and the supercooling can be stably caused. The supercooling case 40 may be installed in any part in the switching chamber 200, and may be an independent case with respect to the switching case 201 or the entire switching case 201 may be the supercooling case 40.

Next, the structure which arrange | positions the supercooling case which comprises a supercooling space in the lower part of the switching case in a switching chamber is demonstrated.
17 is a side sectional view of switching chamber 200 corresponding to FIG. 5 in Embodiment 1 of the present invention, FIG. 18 is a perspective view of a supercooling case used in the present embodiment, and FIG. It is the figure which showed the flow of the cool air to the supercooling case by the form.
As shown in FIG. 17, a supercooling case 81 constituting a supercooling space is disposed below the switching case 201 in the switching chamber 200. A switching chamber air passage 41 is provided around the switching chamber 200, and further includes three outlets through which cool air from the cooler 3 is blown out, a switching chamber rear upper outlet 42, a switching chamber lower lower outlet 44, A switching room ceiling surface outlet 43 is provided. In addition, a damper 46 that adjusts the amount of cold air toward the switching chamber 200 is provided at the entrance of the switching chamber air passage 41.
As shown in FIG. 18, the supercooling case 81 used here has a notch 90 into which the cool air from the lower outlet 44 on the back side of the switching chamber flows on the back of the case, and the notch 90 on the front of the case. A slit 91 for discharging the cold air that has flowed in is formed. Since the cool air from the cooler 3 flows through the supercooling case 81 as shown by the arrows in FIG. 19, the flow rate can be adjusted by a flow rate adjusting device such as the damper 46 at the time of supercooling and when the supercooling is released. preferable.
In addition, the structure which forms the notch and opening which cool air flows in into the case back surface, and forms the slit and opening which discharge | emit the cool air which flowed into the case front surface is applicable to any supercooling case of Embodiment 1. FIG.

Next, the supercooling control of the refrigerator in the first embodiment using the supercooling case 81 shown in FIGS. 17 and 18 will be described. FIG. 20 is a timing chart showing an example of the supercooling control.
In order to supercool the food stored in the supercooling case 81, until the core temperature of the food stored in the supercooling case 81 exceeds the freezing point and reaches a supercooled state (stage 1), the compressor 10, the fan 2. The damper 46 and the like operate so that the switching chamber 200 has an air temperature selected in the range of −2 ° C. to −20 ° C., for example. The compressor 10 and the fan 2 may be controlled by the temperature of another room, and the temperature may be controlled only by opening / closing the damper 46. Here, the damper 46 repeats full open / full close as usual. And when the food core temperature which can cancel | release supercooling is reached (stage 2), the opening degree of the damper 46 will be half-opened, and cold air will mainly flow into the supercooling case 81 side. The half-open angle of the damper 46 may be an angle that gives a vector in the lateral direction to the airflow. Preferably, it is 10 to 60 degrees. The time for which the damper 46 is half-opened is the time (stages 2 and 3) until the freezing is completed after the supercooling is released. Control of the storage period (stage 4) after the freezing of the food is completed is to return the damper 46 so as to repeat full opening / full closing as usual.

  The above control operations of the refrigerator 1 are summarized as shown in the flowchart of FIG. When the supercooling control is started, accumulation of the time of the stage 1 is started (step 51). Next, it is determined whether or not the predetermined time has elapsed for the stage 1 (step 52). If it is determined that the predetermined time has been reached, the damper 46 is opened halfway and the time for the stage 2 is started to be accumulated (step 53). Then, it is determined whether or not the predetermined time has passed for the stage 2 (step 54). If it is determined that the predetermined time has been reached, the damper 46 is fully opened and the normal control is restored (step 55).

  At the time of control for obtaining the supercooling state, there is almost no cold air flowing into the supercooling case 81, so that the supercooling state can be stably created, and only the supercooling case 81 is mostly cooled when the supercooling is released. So that overcooling is released and freezing occurs reliably. Further, there is an advantage that the influence on the air temperature of the switching case 201 is almost eliminated when the supercooling is released. In addition, in the switching chamber 200, the amount of cooling may be adjusted by changing the opening degree of the damper 46 or adjusting the air volume so as to suppress the air temperature fluctuation.

FIG. 22 is a cross-sectional view when a separate supercooling case 202 with a lid for supercooling is installed in the switching chamber of the refrigerator of FIG. Here, the supercooling case 202 is installed on the upper surface of the supercooling case 202 at a position where cool air from the outlet 203 flows. FIG. 23 shows the supercooling case 202 installed in the switching case 201. Thus, the merit of using the supercooling case 202 as a separate case with a lid is that the food in the supercooling case 202 is not easily affected even when foods with different temperature states are stored in the surroundings. . Further, a heat insulating material may be put in the lid portion of the supercooling case 202, but in this case, there is a merit that it is less susceptible to the cold air from the blowout port 203 and can be stably overcooled. is there.
In addition, since temperature unevenness caused by direct blowing of cold air may cause overcooling, a part having a good thermal conductivity may be used for part or all of the lid, the shape of the outlet, The positional relationship between the outlet and the lid may be set within a predetermined temperature unevenness range. The predetermined temperature unevenness range is within 10K, preferably within 5K, and more preferably within 3K.

  In all the embodiments described so far, if a part or the whole of the switching case or the supercooling case is made of a material having good heat conduction (for example, a metal plate such as stainless steel, aluminum, or copper), the temperature inside the case Can be made uniform. Even with a double structure, the temperature can be made uniform.

  The control performed based on the time when the supercooling release timing is recorded in advance in the microcomputer or the like has been described above, but another method for determining the supercooling release timing will be described below. The determination of the supercooling release timing can also be made by determining the state of the supercooled product using an infrared sensor, an ultrasonic sensor, an electric field sensor, or the like.

  When using an infrared sensor, install the infrared sensor on the wall surface of the space where the supercooling case is to be installed so that it can be moved and looked through the entire case, or an array sensor can be used to see the entire case. . As the installation position, for example, the installation can be seen from the back by switching over from the switching chamber 200 and looking over the supercooling case from diagonally above. When entering the supercooling mode, the infrared sensor detects the surface temperature of the food in the supercooling case and calculates the core temperature therefrom. Then, when the calculated core temperature of the food reaches the temperature indicated by the above supercooling condition, the supercooling release stimulus is applied.

  When an ultrasonic sensor is used, the supercooling case is brought into contact with the ultrasonic sensor. The ultrasonic sensor includes an ultrasonic oscillation unit and a reception unit that receives the reflected wave. The installation position may be anywhere as long as it contacts the case when the door of the supercooling case is closed. For example, by installing a spring on the sensor base on the back of the switching chamber 200, the wiring length is the shortest and the cost can be reduced. In addition, when the switching chamber is closed, it can be surely brought into contact with the case. When the supercooling mode is entered, the ultrasonic sensor oscillates ultrasonic waves toward the food in the supercooling case. Since the ultrasonic wave propagates in the substance in contact, the ultrasonic wave propagates to the substance that is contained in the case and is in contact with the case because the sensor is in contact with the case. At this time, compared to when the food is unfrozen or supercooled and the water is liquid, when supercooling is released and ice crystals are generated, the ultrasonic wave is more easily propagated and the oscillated ultrasonic wave reaches the receiver. Speed to do. From this time difference or propagation speed difference, it can be detected that the supercooling has been released and the moisture in the food has begun to freeze, so that the control can be shifted to after the supercooling has been released.

  When an electric field sensor is used, the electric field sensor is installed in the supercooling space. The electrode part of the electric field sensor may have any shape as long as it is made of metal. For example, in order to easily attach to the inner box of a refrigerator, the foil can be attached along the unevenness of the inner box as long as it is foil-like. By making the plate thicker than the foil, it is possible to obtain an electrode that is less likely to break during attachment. Further, it is non-contact type, and may be installed anywhere as long as it is a wall surface of a refrigerator, and can be measured even if there is another substance such as a plastic plate between the substance to be measured. The output of the electric field sensor changes depending on the dielectric constant inside the food. Compared to when the food is unfrozen or supercooled and the water is liquid, when the supercooling is released and ice crystals are generated, the dielectric constant is greatly reduced. Judgment can be made and the control can be shifted to after the supercooling is released.

  In addition to using the apparatus as described above, the temperature of the food may be directly measured with a thermometer, and the supercooling release timing may be determined to determine the supercooling release timing. The thermometer is connected to the refrigerator by wiring and has a wire-like tip. When placing food in a supercooled case, the user inserts this thermometer into the food whose temperature is to be measured. As a result, the temperature inside the food can be measured, so that it is possible to directly recognize whether or not a predetermined supercooling temperature has been reached. When the inside of the food reaches a sufficient supercooling temperature, it is possible to shift to control for releasing the supercooling.

  Next, another supercooling release method that is not the supercooling release caused by the temperature decrease or cold air introduction described so far will be described. Other methods for canceling the supercooling include, for example, a method of applying vibration to the supercooling case or a method of applying a sound wave. As a method for applying vibration, there are a method using a machine, a method using vibration of an operating device in a refrigerator, and the like. Another method for cooling only the supercooling case at the time of canceling the supercooling and preventing the temperature of the switching case from being lowered is to provide a heater on the peripheral wall of the switching case, for example. There is a method of heating only the side with a heater. Further, for example, there is a method in which a heater is provided on the peripheral wall of the supercooling case, the heater for heating the supercooling case is turned on during supercooling, and is turned off when the supercooling is released.

  Note that the supercooling release is not necessarily performed. You may leave as it is, maintaining a supercooled state.

  As described above, the structure of the supercooling space, the method for determining the supercooling release timing, the supercooling release method, and the like have been described in relation to the embodiment of the present invention. Hereinafter, the storage method after the supercooling release is described. .

  When freezing and storing in a range of −10 ° C. or higher after canceling supercooling, it is possible to maintain a state where the knife can be cut quickly even after freezing. By freezing through the supercooled state, the ice crystals inside the food are made finer, so that there is also an advantage that it becomes easier to cut than in normal freezing. Further, since the storage temperature zone is below the freezing point, it can be stored for a long time of about two weeks.

  In the case of storing in the range from -10 ° C to -15 ° C after the supercooling is released, ice crystals are generated in a large needle shape by the normal freezing method and cannot be cut with a knife after freezing. Since the ice crystals formed inside the food are fine, there is also an advantage that it can be cut with a kitchen knife. In addition, the storage period can be long-term storage of 2 weeks to 1 month.

  If it is stored in a temperature range of -15 ° C or less after the supercooling is released, it can be stored for about a month like ordinary freezing, and the ice crystals are fine and it is difficult to destroy food cells. Compared to frozen food, you can feel better quality and texture.

  As a means for changing the storage temperature, there is a method of switching the temperature in one room. Alternatively, a room having a higher refrigeration temperature zone may be used for supercooling and freezing, and the room may be moved to a lower refrigeration temperature zone during storage. The higher freezing temperature zone is higher than −15 ° C., and the lower freezing temperature zone is a temperature zone of −15 ° C. or lower.

  In addition, when frozen through a supercooled state, the ice crystals inside the food can be made into small particles, so that even if the freezing rate is high, that is, the frozen storage temperature is lower than before, it can be cut quickly with a knife. That is, there is an advantage that the storage period in a state where it is cut with a knife or the like is extended, and a new functional and high-quality freezing temperature zone can be appealed.

  Although the case where the supercooling space is in the switching chamber 200 has been described, the supercooling space may be provided in any part of the refrigerator compartment 100, the freezer compartment 300, the vegetable compartment 400, and the ice making compartment 500 in FIG. . Further, all or a part of those rooms may be applied to the supercooling space. Further, the supercooling space may be formed in an independent sealed space in the freezing temperature zone. However, in any case, it is preferable that the structure is such that strong cold air is not directly applied to the supercooled space or the food placed there, or the amount of cool air entering the supercooled space can be adjusted. .

  The refrigerator of this invention can obtain the refrigerator which can implement supercooling freezing by changing the specification of a general refrigerator partially.

  In addition, food that has undergone supercooled freezing in the refrigerator according to the above embodiment has a slow cooling rate when creating a supercooled state, so that ice crystals can begin to form at the same time after the temperature has dropped uniformly to the inside of the food. The ice crystals generated in part do not grow unevenly, the size of the ice crystals formed in the food is reduced, and the food quality can be maintained. FIG. 24 shows the relationship between the cooling rate and the size of ice crystals inside the food. From FIG. 24, it can be seen that the ice crystals formed in the food tend to increase in size as the cooling rate increases.

  Moreover, since the refrigerator which concerns on the said embodiment is indirect cooling when creating a supercooled state, the drying of the foodstuff by direct spraying of cold air is reduced, and freezing burn can also be suppressed. And since the cooling speed which is an important condition when creating a supercooled state is made slow compared with the conventional quick freezing, there are few temperature fluctuations and the whole food can be cooled uniformly.

  In addition, the refrigerator according to the above embodiment is equipped with a supercooling case that includes a substance with a large heat capacity that can suppress temperature changes, or that includes a structure that suppresses direct inflow of blown airflow, so that the door can be opened and closed. The temperature in the supercooling case can be kept stable without being affected by the temperature change.

  In addition, since the refrigerator according to the above embodiment gives the temperature change to the low temperature side only when the supercooling is released, the influence on the existing space such as the switching case is minimized, and is set to another temperature range. It is also possible to use a space or a case together.

  Moreover, since the refrigerator which concerns on the said embodiment can cancel supercooling at the temperature of -2 degrees C or less (for example, -5 degrees C or less), it is energy compared with the quick freezing which is the supercooling cancellation method of a prior art Example. Because it consumes less, it excels in energy saving.

  In addition, the refrigerator according to the above embodiment has an advantage that it is easy to use because the storage temperature after canceling the supercooling can be selected from soft refrigeration and refrigeration for long-term storage depending on the actual usage conditions.

  As described above, according to the present invention, supercooling is set at a set temperature of 0 ° C. or lower for storing food such as fish, meat, vegetables and fruits by cool air from a cooler placed in a refrigerator main body for storing food. A supercooling chamber that is cooled in a state is provided, and the supercooling chamber is slowly cooled at a first temperature that is lower than 0 ° C. and higher than the set temperature until the core temperature of the food reaches substantially the freezing temperature (freezing point, freezing point). When it is determined that the core temperature of the food has substantially reached the freezing temperature, it is slowly subcooled so that a supercooling state can be maintained at a second temperature lower than the first temperature and freezing below the freezing temperature. A control device that cools to the lowest temperature is provided.

  In addition, the control device according to the present invention, when the core temperature of the food stored in the supercooling chamber falls below the substantially freezing temperature and then rises to the substantially freezing temperature and the supercooling state is released, the second temperature or The temperature is lower than the second temperature, and is stored at a preset temperature at which the cooling air is rapidly frozen by increasing the cooling air volume or cooling air speed.

  As described above, in the present invention, the setting control is changed continuously or stepwise at each stage from the freezing point to the supercooling minimum achievement point temperature, the supercooling release, and the complete freezing to the freezing point. For example, control the cool air temperature, cool air flow rate, and cool air speed to the supercooling case to ensure that it is in a supercooled state, lower the minimum supercooling temperature, cancel supercooling, and increase the freezing speed after release to improve the quality. Realize good freezing.

  Therefore, the refrigerator of the present invention adopts the supercooling refrigeration function instead of the conventional quick freezing as the high quality refrigeration function, so that it is possible to realize high quality refrigeration with less energy than conventional, that is, eco refrigeration. It has the effect of being able to.

  In addition, the refrigerator of the present invention reduces the direct blow of cold air into the space for supercooling, can equalize the temperature, and can change the cooling temperature in multiple steps. By adopting the cooling chamber structure or the supercooling chamber case structure, it is possible to realize supercooling and freezing of food with the structure and control of the refrigerator which is not greatly different from the conventional one.

The graph which showed the temperature change when water freezes without supercooling (a) and with supercooling (b). The figure which showed the state of the meat structure | tissue when meat was frozen by normal quick freezing and supercooling freezing, and the meat once frozen was thawed. Side surface sectional drawing of the refrigerator in embodiment of this invention. Side surface sectional drawing which shows the air path structure of the refrigerator in embodiment of this invention. Side surface sectional drawing of the switch room periphery of the refrigerator in Embodiment 1 of this invention. FIG. 3 is a structural diagram of a supercooling case according to Embodiment 1 of the present invention. FIG. 6 is a structural diagram of another supercooling case according to Embodiment 1 of the present invention. FIG. 6 is a structural diagram of another supercooling case according to Embodiment 1 of the present invention. 4 is a timing chart showing an example of refrigerator supercooling control in the first embodiment. 5 is a flowchart showing an example of refrigerator supercooling control in the first embodiment. Side surface sectional drawing of the switch room periphery of the refrigerator in Embodiment 1. FIG. Side surface sectional drawing of the switch room periphery of the refrigerator in Embodiment 1. FIG. Side surface sectional drawing of the switch room periphery of the refrigerator in Embodiment 1. FIG. FIG. 3 is a top view of a duct on the switching room ceiling surface in the first embodiment. FIG. 3 is a structural diagram of a supercooling case in the first embodiment. Side surface sectional drawing of the switch room periphery of the refrigerator in Embodiment 1. FIG. Side surface sectional drawing of the switch room periphery of the refrigerator in Embodiment 1. FIG. FIG. 3 is a structural diagram of a supercooling case in the first embodiment. FIG. 3 is a schematic diagram showing a flow of cool air to a supercooling case in the first embodiment. 4 is a timing chart showing an example of supercooling control of the refrigerator in the first embodiment. 5 is a flowchart showing an example of refrigerator supercooling control in the first embodiment. Sectional drawing when a separate case with a lid for supercooling is installed in the switching chamber of the refrigerator of FIG. The figure which showed a mode that the supercooling case was installed in the switching case. The relationship between the cooling rate and the size of ice crystals inside the food.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Refrigerator, 2 fan, 3 cooler, 4 air path, 5 liquid crystal operation panel, 6 return path for refrigerator compartment, 7 return path for vegetable room, 10 compressor, 41 switching room air path, 41a partition wall, 42 switching room Rear upper air outlet, 43 Switching room ceiling surface outlet, 44 Switching room rear lower air outlet, 45 Switching room bottom air inlet, 46 Damper, 50 Switching room ceiling surface duct, 51 Switch room ceiling surface duct hole, 60 Switching Room cover, 70 fan, 80 switching case, 81 supercooling case, 82 switching case bottom, 83 switching case, 84 supercooling case, 85 switching case, 86 supercooling case, 90 notch on back of switching case, 91 switching case Front slit, 95 Surface temperature measurement device, 96 Ceiling surface, 100 Refrigerated room, 200 Switching room, 201 Switching case, 202 Supercooling case, 300 Cooling Freezing room, 301 freezing case, 400 vegetable room, 401 vegetable case, 500 ice making room.

Claims (24)

  Temperature control that can be adjusted continuously or stepwise from 0 ° C to the temperature of the freezing temperature zone where food such as fish, meat, vegetables and fruits is stored in the refrigerator body where food is stored and cool air from the cooler is stored. A freezing room provided with means, a supercooling room disposed in the freezing room for taking in cold air blown into the freezing room and sucked into the cooler, and a food stored in the supercooling room at a temperature below the freezing point However, the control device controls the freezer to maintain the supercooled state without freezing, and the control device uses the temperature control means to maintain −15 from the freezing point so as to maintain the food in the supercooled state. A refrigerator characterized by adjusting while lowering the temperature in a temperature range up to about ° C.   The refrigerator according to claim 1, wherein the supercooling chamber has an opening for taking the cold air from the freezing chamber and returning it to the freezing chamber.   Temperature control that can be adjusted continuously or stepwise from 0 ° C to the temperature of the freezing temperature zone where food such as fish, meat, vegetables and fruits is stored in the refrigerator body where food is stored and cool air from the cooler is stored. A freezing room provided with means, a cold air adjusting means for circulating the cold air blown into the freezer room and sucked into the cooler, the temperature set by the temperature setting means and the cold air adjusted by the cold air adjusting means A control device for maintaining the freezer in a supercooled state in which the food stored in the freezer is not frozen at a temperature below the freezing point depending on the direction and the amount of cold air, and the control device puts the food in a supercooled state. A refrigerator characterized in that the temperature control means adjusts while maintaining the temperature in a temperature range from the freezing point to about -15 ° C so as to maintain the temperature.   A switching chamber provided in a refrigerator main body for storing food and having a temperature control means for continuously or stepwise controlling the temperature from 0 ° C. to a temperature in a freezing temperature zone; and a closed container disposed inside the switching chamber. A fish, meat, vegetables, fruit, etc. are stored in a lid that can be opened and closed, and a supercooling chamber that keeps the food in the container in a supercooled state that does not freeze even at temperatures below the freezing point; And a closed cold air circulation means for circulating the closed cold air in the supercooling chamber.   The said temperature control means measures the room temperature of the said supercooling chamber or the freezer compartment which maintains the said foodstuff in a supercooled state, or measures and controls the temperature of the said foodstuff, The control is characterized by the above-mentioned. 5. The refrigerator according to at least one of 4.   6. The temperature control means according to claim 1, wherein the temperature control means controls the temperature continuously or stepwise such as a temperature up to a freezing point, a supercooling achievement temperature, a supercooling state release temperature, and a frozen storage temperature. The refrigerator according to at least one of the above.   The food temperature measurement for measuring the temperature of the food, the temperature of the food surface is estimated from the temperature in the supercooling chamber or the freezing chamber, or the food surface temperature measuring means for measuring the food surface temperature with an infrared sensor, 6. The refrigerator according to claim 5, further comprising:   The refrigerator according to claim 5 or 6, further comprising food core temperature measuring means for calculating a temperature in the vicinity of the food center from the measured surface temperature of the food.   The cooling air flow in the supercooling chamber or the freezing chamber that maintains the supercooling state is changed from the flow of cold air in the freezing chamber or the switching chamber in a state that does not maintain supercooling to change the air volume, wind speed, wind direction, and temperature. A cooling air outlet provided to the freezing chamber or the switching chamber in a state where cooling is not maintained, and a cooling air adjusting means provided in a cooling air passage structure in the supercooling chamber or the freezing chamber. Item 9. The refrigerator according to at least one of items 1 to 8.   The cold air adjusting means is a cold air passage structure such as the position and number of the cold air outlets to the room, the bending and length of the air passage from the outlet to the food arrangement position for maintaining the supercooled state. The refrigerator according to claim 9, wherein the refrigerator is provided.   After a certain time has elapsed at the temperature maintained by the control device in the supercooled state, or by measuring the food core temperature or detecting a sudden change in the food surface temperature, it is determined that the supercooling temperature has been reached, or the supercooled state Is determined to be a released temperature, and the food in the supercooling chamber or the freezing chamber is subjected to a physical impact such as temperature, vibration, or ultrasonic wave to release the supercooling to a preset freezing temperature. The refrigerator according to claim 1, wherein the refrigerator is stored or rapidly frozen.   The cooling rate when the temperature in the vicinity of the food center measured by the food core temperature measuring means is in a supercooled state is such that the core temperature of the food is in the range of 300 degrees / hour to 0.35 degrees / hour. The refrigerator according to claim 8.   The refrigerator according to claim 12, wherein the cooling rate is determined when the core temperature of the food is within a temperature range between a freezing point and a temperature 5 degrees lower than the freezing point.   The refrigerator according to claim 13, wherein the supercooled state is maintained for at least 5 seconds.   The food product is cooled so that the difference between the core temperature and the surface temperature of the stored food product is within a range of 0 to 10 degrees when the temperature reaches a temperature at which the supercooled state can be released. Item 15. The refrigerator according to at least one of items 8 to 14.   When the stored food is in a supercooled state, the cold air adjusting means adjusts so that a fluctuation range due to a change in a cooling state of an ambient air temperature for directly cooling the food is within 15 degrees. The refrigerator according to at least one of claims 1 to 15.   The refrigerator according to at least one of claims 1 to 16, wherein the supercooling chamber or the freezing chamber for maintaining the food in a supercooled state is configured by an upper case and a lower case.   The refrigerator according to claim 17, wherein a gap is provided between the upper case and the lower case.   The refrigerator according to claim 17, wherein a member for suppressing air temperature fluctuation in the lower case is disposed on a bottom surface of the upper case.   The refrigerator according to at least one of claims 1 to 16, wherein the supercooling chamber or the freezing chamber for maintaining the food in a supercooled state is configured by an upper case and an upper case of the lower case.   When the stored food is brought into a supercooled state, the position and size of the opening or lid structure for taking in cool air from the supercooling chamber container, case, etc. so that the air temperature unevenness in the supercooling chamber is within 15 degrees. The refrigerator according to at least one of claims 1 to 20, wherein the refrigerator is formed.   The refrigerator according to claim 11, wherein the supercooling release is performed by introducing cold air into the supercooling chamber.   23. At least one of claims 1 to 22, wherein the supercooling canceling means for canceling the maintained supercooling state can select a storage temperature zone after the supercooling cancellation from a temperature zone of -5 ° C or lower. The refrigerator in any one.   The food stored in the refrigerator body, such as fish, meat, vegetables, and fruits, is kept in a supercooled state that does not freeze at temperatures below the freezing point while gradually reducing the temperature by means of temperature control. A supercooling chamber for changing the air volume, wind speed, wind direction and temperature of the cool air blown into the supercooling chamber and circulated through the supercooling chamber, and the temperature control means and the cold air adjusting means. A refrigerator comprising: supercooling cancellation means for canceling a supercooled state of food stored in the cooling chamber in a supercooled state by changing a state of cool air in the supercooled chamber.

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