JP4775340B2 - refrigerator - Google Patents

Description

  The present invention relates to a cryopreservation technique using supercooling, and relates to a refrigerator (also referred to as a refrigerator-freezer) using the technique.

  It is 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 decreases, the phenomenon that the surface begins to freeze first occurs, and the ice crystals formed on the food surface expand while drawing out the unfrozen water inside the food. Large acicular crystals are formed. Since large needle crystals destroy the original structure of food such as meat and fish, it is very difficult to return the shape of the food when thawed to the state before freezing. For most foods, how to make small ice crystals during freezing and how to avoid breaking down the original structure of foods with ice crystals can be said to be a means to improve freezing quality. In addition, recent needs for refrigerators for home use are gathered in “frozen” or “frozen storage” due to changes in eating habits and lifestyles. The same applies to commercial refrigerators. 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 known. That is, a representative high-quality freezing technique is quick freezing, and a method often used for quick freezing quality evaluation is a drip outflow comparison when thawing meat or the like. 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 for the small amount of drip outflow of the rapidly frozen food, that is, the formation of small ice crystals 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 for discharging cold air to cool food in the quick freezing container are provided above the opening of the upper surface of the quick freezing container. There are some which are going to carry out quick freezing in a refrigerator by installing in a room (for example, refer to patent documents 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, a large amount of energy is required to blow the cryogenic cold air at the time of quick freezing, and it can be said that energy saving 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, quick cooling is performed to cool the foods (vegetables, fruits, meat, fish, etc.) to the vicinity of the freezing point (freezing point) 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).

  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). .

Japanese Patent Laying-Open No. 2005-83687 (pages 6-17, FIGS. 2 and 3) JP 2003-180314 A (column 0012) JP-A-8-252082 (Claim 1, 0015 column) JP 2000-325062 A (claim 1, column 0014)

In the conventional technology, when the supercooling state is low, the cooling speed is slow, and if the supercooling state is too long, the food quality may be deteriorated due to oxidation or bacterial propagation. 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. In addition, it was difficult to seal all foods that could be stored in the freezer.

  Further, an object located in a static magnetic field is irradiated with an electromagnetic wave having a predetermined frequency determined according to the magnetic field strength of the static magnetic field continuously or intermittently, and hydrogen nuclei constituting water molecules contained in the object If a supercooled state is created by causing nuclear magnetic resonance to lower the freezing temperature of water and lowering the freezing temperature to a normal temperature or less, a complicated and large apparatus is required, and the practicality for food is reduced. For example, it is too large for a commercial refrigeration warehouse, and the cost of the apparatus is too high, so it is considered difficult to put it into practical use when it is considered to be mounted on a home refrigerator. Furthermore, in recent years, attention has been focused on health damage caused by electromagnetic waves, and when applying to devices that can be easily opened and closed, such as refrigerators for home use, business use, and distribution, pay sufficient attention to the effects on the human body. There was a problem that it was necessary.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to be able to freeze with less energy without impairing the quality of food, that is, a simple structure for high-quality freezing. It is to obtain a refrigerator and a frozen storage method that can be realized in

  In addition, the object of the present invention is to realize high-quality refrigeration with a simple structure that cools at a higher cooling temperature than before without freezing at a low temperature with cryogenic cold air, which has been common knowledge in conventional refrigeration methods, and energy saving It is to obtain a refrigerator and a frozen storage method that can exhibit the merits of both high-quality freezing and high-quality freezing.

The refrigerator of the present invention sets the temperature of the cooling chamber and sets the temperature of the cooling chamber set by the first temperature setting means for setting the food in a supercooled state by the cold air introduced into the cooling chamber, and the first temperature setting means. And a third temperature setting means for setting the food that has been released from the supercooled state of the food by cold air at a temperature lower than the lower temperature to a temperature at which the food is frozen and stored, and is set by the third temperature setting means. The temperature of the cooling chamber can be set regardless of the temperature of the cooling chamber set by the first temperature setting means .

  The refrigerator of the present invention adopts the supercooling refrigeration function with a simple structure instead of the conventional quick refrigeration as the high quality refrigeration function, so the high quality refrigeration with less energy than the conventional, that is, energy saving as a global environmental measure It has the effect that refrigeration can be realized.

  In addition, the refrigerator of the present invention adopts a temperature-controlled cooling structure in which cold air is introduced into a space for supercooling and the cooling temperature can be changed into a plurality of temperatures. Control has the effect of realizing supercooled freezing of food such as meat.

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 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.

  In the case of cryogenic freezing set to −60 ° C. and the case of freezing through a supercooled state set to −18 ° C., the former crystals are compared by freezing the angarose gel in the cooling chamber and comparing the crystal state Are needle-like and grow large, whereas the latter crystals are finely and uniformly spread on the grain. When such a difference occurs during freezing of food, the original structure of the food is mediated by crystals in the former, whereas the latter is hardly affected by ice crystals. A good frozen food will be obtained.

  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. Control mechanism for adjusting cold air, structure for cases for storing food, etc., device or control mechanism for determining completion of supercooling necessary to reliably realize supercooling cancellation, and required for supercooling cancellation A device for providing stimulation or a control mechanism. It also has a cooling and storage function for maintaining high-quality freezing after the release of supercooling.
First, supercooled freezing is divided into the following five states depending on the food temperature.
(1) Unfrozen state The food temperature is above the freezing point of the food.
(2) Supercooled state The food temperature is below the freezing point of the food and is not frozen. As the food temperature continues to decrease, it can be seen that it is in a supercooled state.
(3) Supercooling release When the food temperature returns from the temperature below the freezing point to the freezing point.
(4) Freezing start to freezing completion state: A state in which the food reaches the freezing point and undergoes a phase change (if it is water, it changes from liquid water to solid ice) and changes at a constant temperature.
(5) Freezing completed / frozen storage state: Food is frozen through the process of (4).
Here, freezing points of main foods will be described. -1.7 ° C for beef / pork, -1.3 ° C for tuna, -1.7 ° C for potato, -1.2 ° C for strawberries, -2.0 for apples. ° C. (Reference: General food industry, p.922 (1975))
In the state of (1)-(2), the conditions necessary for supercooling rushing (making the food at a temperature below the freezing point in an unfrozen state) and deepening the supercooling (when in the supercooled state) (Reducing the temperature to reach) conditions, (3) for releasing the supercooled state and starting freezing, (4) and (5) for maintaining the goodness of the supercooled frozen food There is. When (1)-(3) is controlled to obtain a sufficiently deep supercooling degree (temperature difference between the freezing point of the food and the temperature reached by supercooling), the effect disappears by (4) and (5). There is nothing. However, when in the supercooled state, the door is opened for a long time when food is taken in or out, or when the set temperature is set to the freezing point temperature or higher and the temperature in the supercooled chamber becomes, for example, 0 ° C or higher, and the supercooled state is released. Will restart from state (1) again. Next, steps (1) to (3) will be described.

  First, a description will be given based on the examination results when beef having a thickness of 15 mm and 150 g is added as food. The supercooling conditions in the supercooling chamber (same as the supercooling space) of the refrigerator of the present invention will be described. The points to be noted when setting the supercooling conditions are the difference between the cooling rate and the minimum point of the core temperature of the food to be cooled (the temperature reached in the supercooled state) and the freezing point. 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 flavor of the food is reduced, nutrients such as free amino acids are reduced, and 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 cooling air adjustment are performed continuously or stepwise until the food is released from the supercooling to the supercooling state below the freezing point and completely frozen until the freezing point is reached. 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 an antibacterial function.

First, the cooling rate will be described for the supercooling entry condition. The food is cooled from the surface, and the center of the food is cooled by heat conduction according to the type and thickness of the food. That is, the central cooling rate is determined after the cooling rate of the food surface is determined. In addition, when controlling the temperature change of food in a home refrigerator, it is common to detect the surface temperature of the food. When the food is supercooled, the temperature of the food center and the temperature of the food surface decrease with a similar tendency. The beef is 15mm thick and 150g, and the air temperature around the food reaches the temperature set in about 30 minutes, for example, -5, -7, -10 ° C, but the food surface temperature reaches the freezing point. The higher the set temperature is, such as about 120 minutes, about 80 minutes, and 60 minutes or less, the delay will occur. The food center temperature has a small difference in food surface temperature difference, and each temperature difference is about 0.5 to 3.0 degrees. However, the higher the air set temperature, the smaller the temperature difference between the surface and the center, and the lower the set temperature, the smaller the degree of supercooling, that is, the energy during freezing. The cooling rate is calculated in the range where the food surface temperature is from 3 ° C to 0 ° C. The cooling rate in this temperature zone correlates with the possibility of cooling entry, and when the set temperature around the food is -5 ° C, the cooling rate of the food surface is about 3.5 ° C / h and the set temperature is -7 ° C. Then, the cooling rate of the food surface is about 5 ° C./h, and when the supercooling at the set temperature of −10 ° C. is shallow, the cooling rate is about 10 ° C./h. From this result, when there is a distance between the food surface and the center as a condition for entering into supercooling, the food surface cooling rate is 10 ° C./h or less, preferably 5 ° C./h or less. Is shown. At this time, there is also a difference in the temperature difference between the food surface and the center. At the set temperature of -5 ° C, the temperature difference between the food surface and the food center is about 1 degree (K) (the cooling rate at the food center is about 3.5 ° C / h). The temperature difference at the center is about 2 degrees (K) (the cooling rate at the center of food is about 5 ° C./h). On the other hand, at the set temperature of −10 ° C. where the supercooling is shallow, the temperature difference between the food surface and the food center is about 3 degrees (K) (the cooling speed of the food center is about 10 ° C./h). From this result, it is shown that the temperature difference between the food surface and the center is 3 degrees (K) or less, preferably 2 degrees (K) or less, as a condition for entering into supercooling. When the distance between the surface and the center of the food is small, that is, when the heat capacity of the food is small, for example, when the temperature is lower than −10 ° C., for example, at −15 ° C. Food is obtained.

From the above, the cooling rate of the food surface is considered to be a condition that the temperature difference between the food surface and the center is a cooling rate of 3K or less. At this time, it is considered that the following phenomenon is avoided. B) When the temperature difference between the food surface and the center becomes large, the density of moisture contained in the food changes, and convection of moisture contained in the food occurs due to the density difference. For this reason, the association rate of water molecules increases, and the growth of nuclei is promoted, so that the supercooling is easily released. B) If the food surface freezes first, the food surface forms a stable environment with the temperature of the freezing point being constant. Therefore, the food is stably held at the freezing point, and all the cooling heat conducted from the food surface is used as latent heat, and freezing proceeds. For this reason, when the surface of food freezes, the whole food will not be supercooled. On the other hand, the air temperature around the food varies depending on the type and thickness of the food in order to keep the food unfrozen below the freezing point, but generally the air temperature around the food is -10 ° C or higher. It is obvious that the upper limit of the air temperature around the food is obviously below the freezing point of the food to be supercooled. For example, beef and pork are below -1.7 ° C. Let it be −2 ° C. The cooling rate at which the temperature difference is suppressed to 3 degrees (K) or less is preferably about 3.5 ° C./h to about 10 ° C./h, particularly about 5 ° C./h or less. However, when the thickness is 10 mm or less, such as a thin sliced meat, the temperature is reduced to 300 ° C./h or less, and supercooling is entered, and about 2 to 50 ° C./h is required for a lump of about 40-50 mm thickness. In any food, the temperature difference between the food surface and the food center may be suppressed to about 3 degrees. However, in the case of a homogeneous super-coolable food that is easily gelled and moisture is easily held at a certain position, such as yogurt, it is supercooled at about 3.5 ° C./h to about 10 ° C./h. Even with a temperature difference of 5-10 degrees, it is supercooled.

  For the temperature unevenness around the food as one of the obstruction factors when entering the supercooling and maintaining the supercooled state, it is preferable to suppress the unevenness of the cooling rate, that is, to reduce the cooling rate around the food. In addition, in order for the refrigerator to control the air temperature to a certain temperature, avoid fluctuations in the air temperature around the food due to the effects of various equipment operations, such as turning on / off the compressor, turning on / off the internal fan, and opening / closing the damper. I can't. Due to the air temperature fluctuation, the temperature fluctuation inside the food becomes large. For this reason, the convection of the water | moisture content inside a foodstuff is accelerated | stimulated, ie, the association probability of a water molecule becomes high, and it becomes easy to cancel | release supercooling. In order to avoid this and enter the supercooling, the temperature fluctuation range until the temperature exceeds the freezing point of the food (for example, −1.7 ° C.), that is, the supercooled state, is within about 6 degrees (K) in the experiment. Met. Regardless of the size and type of food, the surface of the food should not be stimulated to release supercooling. For this reason, it is desirable that the air temperature fluctuation around the food is within 6K as described above. However, it is possible to create a supercooled state even if the degree of supercooling is somewhat shallower or the probability of occurrence of supercooling is low. For example, in the vicinity of the outlet, the temperature fluctuation is larger than 6K, for example 15K. It is possible to rush into supercooling even in a difficult environment, and deepen the supercooling with foods that are easy to supercool. In order to enter a supercooled state and deepen the supercooling, it is not always necessary to cool at the same temperature. When the food is cooled at a certain temperature, the food is cooled, the food surface temperature is lowered, the temperature difference from the air temperature around the food is reduced, and the food surface temperature is almost stabilized at the air temperature around the food. Therefore, in order to deepen the supercooling, it is preferable to cool (deepen) while keeping the temperature difference between the air temperature around the food surface and the food at a certain level or more. For this purpose, the air temperature around the food may be lowered according to the food surface or the center temperature. In this process of deepening the supercooling in a household refrigerator, a predetermined time is elapsed after a predetermined time (a time until the food center temperature reaches −1 ° C. from food input, which has been examined in advance in an experiment; for example, 2 hours). The set temperature may be decreased by 1 ° C. every time (every time when the food temperature decreases by 1 ° C., which has been studied in advance; for example, 0.5 hour). By doing so, the food can be cooled while maintaining the temperature difference between the food surface and the air temperature around the food, so that the supercooling can be deepened. Conversely, if the air temperature is very uneven or the air temperature fluctuates greatly, the temperature distribution on the food surface will increase, or the heat transfer coefficient on the food surface will increase, and crystallization will occur from where it is easy to cool the surface. At the beginning, the supercooling is released.

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, there is a tendency to be suppressed to less than half that of normal frozen frozen one. Potatoes and other 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 can be removed or crushed It was said that freezing was the common sense for freezing curry deliciously. When this freezes and thaws potatoes, it becomes scary and the texture becomes worse. However, if the curry is frozen by supercooled freezing, the texture of the potato is almost the same as that before freezing even after thawing, and it does not become a scaly or sticky texture. Starch, the main ingredient of potatoes, is composed of amylose and amylopectin. However, conventional freezing destroys these three-dimensional structures by the growth of ice crystals. Because there is no thawing potato, it becomes scary. 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 thawing potatoes does not deteriorate after supercooled freezing. 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.

In the above examination, the wind speed at which the cold air around the food flows is assumed to be about 0.5 m / s. The cooling rate of food is determined by the temperature difference between the food surface and the air temperature around the food and the convective heat transfer coefficient. This is because the smaller the convective heat transfer coefficient, the smaller the temperature difference between the food surface and the center, and the quicker supercooling. In addition, although the cooling rate is prescribed | regulated by the time-dependent change of food surface temperature, in an actual product, a thermopile is mentioned as a detection means of food surface temperature. In this method, the surface temperature of food is detected in a non-contact manner by receiving radiant heat from infrared rays emitted from the surface of the food. By this, the temperature and area of the food are inferred from the thermopile detection temperature when the food is put into the switching room of the refrigerator, and further, the heat capacity of the input food is inferred from the subsequent change in the thermopile detection temperature. In addition, the control time in each process can be extended or shortened according to the input food.

Supercooling is originally an unstable state, and is canceled by applying some kind of stimulus. Generally, it is said that it is released by vibration. For example, when a sealed container is filled with water without any gaps, it will not be released even if the container is violently shaken. Even if the door is opened / closed fully open / closed several tens of times, the supercooling will not be released. However, when only about 1/2 of water is put into the sealed container, it is canceled at once. From this, it is considered that a space in which the liquid flows freely is necessary to release the supercooling by vibration. In the case of food such as meat, fish, fruit, etc., each cell and the cell are filled with moisture without any gaps, and thus correspond to a sealed container filled with water without any gaps. In fact, in the switching room containing the supercooled meat, the supercooling is not canceled even if the door is opened and closed repeatedly. In addition, the percentage of the whole food that forms ice nuclei when the supercooling is released depends on the degree of supercooling. For example, when the degree of supercooling is 4 degrees (K), it is clear from the following formula of freezing rate that ice nuclei are formed at 5 percent of the water content of the whole food.
Freezing rate (%) = (Cp * rV * ΔT) / L * rV * 100
Cp; Specific heat (kJ / kgK)
r; Density (kg / m3)
V: Volume (m3)
L: Latent heat (kJ / kg)
ΔT: Temperature difference (K)
If the degree of supercooling is 4 degrees, the ice crystal shape is minute. After the supercooling is released, when the food temperature returns from the temperature below the freezing point to the freezing point (the temperature difference at this time is the degree of supercooling) until the freezing starts in the next process until the freezing is completed, It reaches the freezing point and causes a phase change (if it is water, it changes from liquid water to solid ice), and it is in a state of transition at a constant temperature. After that, freezing is completed and frozen at the set temperature. Save state. As long as supercooling occurs, the subsequent freezing speed will not affect the ice crystal shape, and if the ice nuclei are distributed throughout the food, fine ice nuclei are formed during supercooling. Become. As described above, it is possible to determine the percentage of the total amount of water in the food when ice nuclei are formed by the freezing rate when the supercooling is released. According to the experimental data, it is frozen when the supercooling degree is 0.8 degrees. The rate was about 1 percent and the ice crystals were large needles. When the degree of supercooling increases to 2.6 degrees, the ice crystals become quite small, but the freezing rate is about 3 percent. When the degree of supercooling increases to 4.1 degrees, the ice crystals are so small that they cannot be discerned by the naked eye. The freezing rate is about 5 percent. In this way, ice nuclei generated at the time of release of supercooling are only a few percent of the total water content of the food, but the ice nuclei are uniformly formed throughout the food, which affects the ice crystal state during subsequent frozen storage. The In addition, since the energy stored in the supercooled state is used as the energy for generating ice nuclei, the greater the degree of supercooling and the greater the amount of energy stored, the greater the number of ice nuclei that are generated when the supercooling is released. Therefore, it is considered that the ice crystal diameter is reduced accordingly, and the effect of food damage due to ice crystals is considered to be reduced.

  In order to put the food stored in the refrigerator into a supercooled state as described above, it is necessary to cool the food with a certain range of cooling capacity. This means that even if the cooling capacity for cooling the food is too weak or too strong, the supercooling state does not occur or the supercooling state is released immediately. If the cooling capacity is weak, the stored food tends to enter the supercooled state, but the cooling capacity around the food is weak = the temperature is high, and the food temperature reaching point in the supercooled state is also high, so the supercooling Does not deepen (= lower temperature) but cancels overcooling. In general, the greater the depth of supercooling, the greater the energy, and fine crystals in the food are produced, resulting in high-quality refrigeration. do not do. When the depth of supercooling is 3K (for example, when the food reaches a temperature of -4 ° C in a supercooled state and then releases and then the temperature rises to -1 ° C instantaneously), the amount of drip outflow when thawing meat is large. In order to make a difference, it is necessary to drive further into the supercooling depth. On the other hand, if the cooling capacity is strong, it can be frozen as soon as it reaches the freezing temperature of the food, or even if it enters the supercooled state, it leads to a phenomenon that the strong cooling capacity is immediately released as a stimulus. Therefore, a deep supercooling degree cannot be obtained. Therefore, it is a necessary condition to cool food with a certain range of cooling capacity. As described above, when the cooling capacity is weak (= when the room temperature is high), when the food is put into the refrigerator, the room temperature changes at about −3 to −4 ° C., and the food is cooled at this temperature. However, as long as the room temperature is between -3 and -4 ° C, the food temperature will naturally not be lower than that, so deep supercooling cannot be obtained, so the room temperature will be lowered little by little. Release when the temperature reaches about -3 ° C. In this way, when the cooling capacity is weak (= high temperature), although it enters into the supercooling, it does not enter deeply, so the user rarely feels a significant difference as a food. If the cooling capacity is strong (= room temperature is low), freezing starts when the freezing temperature is reached without entering the supercooling state.

  However, if the air temperature is set to −10 ° C. or higher, the room temperature can only be lowered to the level of about −7 to −8 ° C., but it is sufficiently achievable at this temperature to obtain a supercooling depth of 3K or higher. Become. Moreover, when lowering the set temperature, it is possible to drive deeper supercooling deeper by lowering the temperature from around the freezing temperature (about −1 ° C.) of the food. Also, when reducing the temperature, it is better to gradually reduce the temperature so as not to give a strong stimulus to food. For example, even if a case where the supercooling is canceled when the set temperature is decreased by 2 degrees occurs, the stimulation due to the temperature gradient is alleviated when the temperature is decreased by 1 degree. Subsequently, as already described, another supercooling requirement is air temperature distribution (unevenness) near the supercooled food. This is because if the food is not installed in a certain range of air temperature distribution (unevenness), the supercooling does not start or the supercooling is released immediately. This is because freezing or supercooling release occurs from a low temperature part in the temperature unevenness of the food, and as a result, the freezing or supercooling release is performed so that the influence reaches the high temperature food part and follows it. It is. Therefore, it becomes a necessary condition to cool with a certain range of temperature distribution (unevenness). Specifically, the smaller the air temperature unevenness, the better. However, since various factors such as the actual machine variation of the refrigerator and the size and shape of the stored food occur, the temperature unevenness is preferably about 2K or less. If the experimental results regarding the temperature unevenness and the depth of supercooling are summarized statistically regardless of the room temperature, it can be seen that the occurrence probability of supercooling increases when the temperature unevenness is 2K or less. By multiplying this condition by the above temperature setting, the probability of occurrence of supercooling can be very close to 100%.

In order to adjust the cooling strength, the temperature is kept constant by ON / OFF of a compressor mounted on the refrigerator and a damper that is adjusted by a temperature sensor installed in each room. Therefore, in each room of the refrigerator, there is always a time (cold air ON / OFF) that is not considered to be a time during which cold air is supplied. Therefore, in order to adjust to the set room temperature, cold air having a temperature lower than the room temperature must be supplied. However, in order to realize supercooling, the food needs to be supercooled at the above-described temperature. In such a case, we want to keep cooling at a constant temperature of -15 ° C or higher, preferably -10 ° C or higher, which is a necessary condition for air temperature near foods. It is difficult to realize, and the cold air temperature around the supercooled food is controlled. There are two main means for realizing it. The first is means for bringing the cool air temperature for cooling the room closer to the optimum supercooling temperature. When cooling a room that can be set to a freezing temperature zone in a normal refrigerator, the cold air temperature reaches a level of about −25 ° C. at the cold air supply port (air outlet). This temperature is a value far from the optimum supercooling temperature, and it becomes an effective means to control the temperature of the source stream of this cold air supply. As for the means, first, means for raising the cold air temperature by lowering the refrigerating capacity of the compressor can be mentioned. However, since the original cooling capacity other than supercooling must be secured, the refrigeration capacity is not reduced by reducing the drive speed of the compressor by inverter control etc., rather than reducing the capacity of the compressor itself. To increase the cool air supply temperature. When the compressor is actually reduced at the 10 rps level, the blowing temperature is expected to rise by about 3 to 5K. Further, even in the rotation speed of the blower fan in the refrigerator that supplies the cold air, it is possible to control the supply cold air temperature by changing the rotation speed. When the rotational speed of the fan is actually lowered, the cool air speed is reduced and convective heat transfer is suppressed, so that the cool air temperature is also lowered. Therefore, conversely, by increasing the rotational speed of the fan, heat exchange is promoted and the cold air supply temperature rises. When the internal fan actually rises by 300 to 400 rpm, the cold air temperature is expected to rise by about 2 to 3K. In addition, it is possible to increase the cold air temperature by installing a heat insulation heater around the cold air supply outlet.

  The second means is not to raise the cold air supply temperature, but to raise the cold air temperature before the cold air hits the food so that the cold air having a low temperature is not directly applied to the vicinity of the food as much as possible. In order to realize this, it is possible to increase the distance that the cold air reaches the food from the cold air supply port. For example, it is possible by providing a cold air rectifying guide around the cold air supply port or by providing an obstacle between the outlet and the food installation position. As a result, the cold air temperature reaching the periphery of the food can be raised by heat exchange in the middle. In addition, the cooling speed of the cold air can be reduced, so that the food can be slowly cooled without giving a strong stimulus. As an example in which an obstacle is installed between the outlet and the food installation position, a configuration in which a lid shape is added above the food storage case is possible. With the lid, the distance from the cold air outlet on the back side of the refrigerator to the opening of the case provided on the door side can be taken more than half the length of the case. If the airflow analysis in this case is performed, it is possible to increase the cold air temperature near the food by adding the lid shape, and further to decrease the wind speed. In addition, a damper that controls the supply of cold air between a blower fan that circulates cold air in the refrigerator and the outlet serves as a cool air supply shutter that adjusts the angle to reduce the amount of cold air. The damper can be not only fully closed and fully opened, but also can be adjusted to an angle in the middle to reduce the amount of cold air and to suppress the wind speed blowing on the food. The wind speed of the cool air outlet is adjusted to 1.0-1.2 m / s by adjusting the damper opening, the case is provided with a lid, and the cool air is supplied into the case from the door side so that the wind speed in the case is 0.1. The supercooled state is maintained at −0.5 m / s. Although the first means and the second means may be performed individually, the temperature in the vicinity of the food can be set to a temperature convenient for supercooling.

  The means for improving the temperature unevenness is a means for suppressing temperature unevenness and hunting by reducing the number of ON / OFF times of the cold air supply. As described above, the controller 16 reduces the number of revolutions of the compressor 10 and supplies a higher cool air temperature, thereby increasing the time required to reach the set temperature and reducing the number of ON / OFF times. Unevenness and hunting can be improved. Thus, the means for reducing the number of ON / OFF times = the cooling capacity is reduced, so this is also an effective means for reducing the amount of cool air by adjusting the damper angle as described above. Furthermore, the cold air temperature and the wind speed can be adjusted by the shape of the air guide at the air outlet and the shape of the obstacle between the cold air outlet and the food.

  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.

  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 refrigerator 1 has a food storage room, which is provided with an open / close door at the top, a refrigerator, vegetable, chilled, soft frozen (-7) from the freezing temperature zone (-18 ° C) below the refrigerator room 100. 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 are an operation switch for adjusting the temperature and setting of each room, a liquid crystal display for displaying the temperature of each room at that time, and an operation panel 5 operated and set by the operation panel. A control device 16 is provided for controlling the opening and closing of the compressor and the damper so as to adjust the temperature of the temperature detector disposed in each storage room to the set temperature.

  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. Also, the temperature placed in the cabinet together with the operation switch, the control operation and display of the operation panel 5 by software stored in the microcomputer attached to the control board of the control device 16 arranged in the outer shell of the refrigerator 1 on the back side. The compressor 10 and the blower fan 2 are controlled based on the detection signal of the sensor. 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 surface when 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 is a normal switching case, and the lower case 81 is supercooled for food. It is a supercooling case as a supercooling space which is a cooling chamber to be in a state. 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. A gap of about 15 mm is opened between the upper case 80 and the lower case 81. When the refrigeration temperature is set, cold air of about −20 ° C. blows out from the cold air outlets 42 and 43 to the switching chamber. According to this structure, the airflow blown into the room cools the inside and the periphery of the upper switching case 80 and flows into the lower case from the gap between the upper case and the lower supercooling case 81. The airflow is also a gap in the direction perpendicular to the airflow, and the airflow is prevented from flowing directly into the lower case, so that the air temperature rise of the supercooling case 81 and the wind speed without the case are suppressed. 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 30 mm between the switching case 80 and the supercooling case 81. In this case, when this cooling chamber is supercooled, that is, cool air is introduced into the supercooling case 81 and cooled. In addition, there is an effect that the release can be efficiently performed by improving the flow of the cold air at the time of canceling the supercooling. However, if the gap is too small, it is necessary to provide another opening in the lower case for rapid cooling or direct cooling at the time of supercooling entry or release of supercooling. If the opening for release is provided, the blown cold air does not directly enter, and there is no problem even if the airflow is at a natural convection level. Even if cold air is directly introduced, the same effect can be obtained by reducing the wind speed or increasing the cold air temperature as described above. 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. The depth of the supercooling case may be about 70 mm, or it may be about 140 mm or more, for example, about 300-600 mm, assuming frozen storage of bread and chilled storage of large yogurt. The upper case may have the same capacity as the lower case, or a depth of several times the capacity of the lower case as shown in the figure. 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. A gap for supplying cool air is provided between the upper cooling case and the supercooling case. 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.

  As already explained, the cooling rate needs to be limited to some extent. For example, in foods such as pudding and yogurt, a supercooled state is created by setting the cooling rate within the range of 300 ° C / h to 0.35 ° C / h, preferably around 3.5 ° C / h. 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 a deep supercooling temperature is good is good, as already explained. As the supercooling temperature deepens, the amount of sensible heat energy stored in the supercooling increases. The energy of instantaneous latent heat change becomes large, and by using this energy, many ice nuclei are generated at the same time in the food when the supercooling is released, and ice crystals grow using the ice nuclei as nuclei. It can be said that a large number of small ice particles can be uniformly formed in the food, and the ice crystals in the cells have less influence on the cells, such as reducing the destruction of the cells and suppressing the drip outflow during thawing. Furthermore, since the food is not directly blown with cold air, or the wind speed is suppressed or the temperature fluctuation is suppressed, drying and frosting of the food can be suppressed. In addition, the longer the time in the supercooling state, the higher the possibility that the supercooling arrival temperature becomes lower. As a result, the degree of supercooling increases, so that a certain amount of time is required to maintain the supercooled state.

  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 order to maintain the supercooled state, it is also important to change the air temperature in the supercooled space (temperature difference with time). The temperature around the food and the wind speed are also night, and the range of the air temperature fluctuation is preferably within 5 ° C. However, if it is within 10 ° 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 of the set value set in advance in a microcomputer or the like may be reduced for device control based on a detection value of a thermistor (not shown). It is preferably within 4K (4 ° C), more preferably within 1K (1 ° C).

  Also, the air temperature unevenness should be within a few degrees of supercooling, but it is desirable to have a supercooling degree of less than 2 degrees for the supercooling entry. When trying to cool, there is a partial freezing. That is, regardless of the temperature of the supercooling chamber, when the temperature nonuniformity and the depth of supercooling are obtained through experiments, when the temperature nonuniformity becomes 2K or less, the probability of occurrence of supercooling approaches 100%. Therefore, it is important to control the temperature in the vicinity of the food and reduce the wind speed, and the opening position and size of the supercooling chamber are simulated so that cold air does not flow around the entire supercooling chamber and the local temperature is not too low. The airflow distribution and temperature distribution are obtained and selected by

  Regarding the temperature setting standard for supercooling refrigeration, there are, for example, −3 ° C. to −10 ° C. in a temperature zone that satisfies the cooling rate as described above and has a high probability of occurrence of supercooling. 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 | decompressing, 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.

  Next, supercooling control of a supercooling chamber (supercooling case) that is a cooling chamber 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 control of the refrigerator which is supercooling control stored in the control device 16. In order to supercool the food contained in the supercooling case, the core temperature of the food in the supercooling case, but if the difference between the surface temperature and the core temperature is small, the surface temperature exceeds the freezing point and reaches the supercooling state. Up to (stage 1), the compressor 10, the fan 2, the damper 46, etc. are brought to an air temperature selected in the range of −2 ° C. to −20 ° C., for example, in the room with the supercooling case (here, the switching chamber 200). To work. 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 control operations of the control device of the refrigerator 1 are 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). .

  The switching room 200, which is a cooling room that can realize the stored food in a supercooled state, is refrigerated (about 3 ° C), chilled (about 0 ° C), soft frozen (about -5, -7, -9 ° C), It is possible to switch to a plurality of temperature zones such as refrigeration (about −17 ° C. or lower), and these temperatures are controlled by a control device 16 constituted by a microcomputer or the like provided at the upper part of the rear surface of the refrigerator main body. By switching the blower or the like, the switching setting is performed to the set temperature. An example of the display panel 5 provided on the door surface is shown in FIG. FIG. 25 is a diagram showing a liquid crystal display panel representing an embodiment of the present invention. In the figure, reference numeral 5 denotes a display panel, which selects a room selection switch 5a for selecting any one of a refrigerator room, a vegetable room, a freezer room, and a switching room, temperature adjustment of the selected room (storage room), or quick freezing. A temperature adjustment / quick cooling switch 5b, a supercooling freezing (instant freezing) switch 5c for selecting supercooling freezing (instant freezing), and an ice making changeover switch 5d for selecting the ice making mode from normal, transparent, rapid, and stop are provided. (Here, supercooled refrigeration freezes instantly and is also referred to as instantaneous freezing in the present invention.) In addition, the display panel 5 includes rooms in various temperature zones (refrigerated room, freezer room, switching room, vegetable room, supercooled room). For example, the set temperature and the current temperature may be displayed. When the surface temperature of the food temperature is measured with a non-contact infrared sensor or thermopile, the measured food surface temperature (for example, the food temperature as shown in FIG. 9) is displayed on the liquid crystal display panel 5. The supercooled state and the surface temperature of the food can be known at a glance, so that it is not necessary for the user of the refrigerator to grasp the passage of time or to check how much the food has been cooled by opening the door. Here, when it is desired to perform quick freezing, the temperature adjustment / quick cooling switch 5b is kept pressed for a predetermined time (3 seconds) to enter the quick freezing mode and quick freezing is performed. When supercooled refrigeration (instantaneous freezing) is to be performed, the supercooling refrigeration (instantaneous freezing) switch 5c is pressed to enter the supercooling mode, and supercooling cooling or supercooling refrigeration is performed. The refrigerator of the present invention has an ice tray cleaning mode. When the ice making switch 5d is continuously pressed for a predetermined time (about 5 seconds), the ice tray cleaning mode is entered and the ice tray is cleaned. The temperature adjustment of the selected room (storage room) is performed by the temperature adjustment / quenching switch 5b. In this embodiment, the temperature is displayed in three levels of strong, medium and weak. In this temperature display, the set temperature may be directly displayed on the display panel 5. Furthermore, when the set temperature of the cooling chamber is set to the supercooled state, the case where the supercooled state is released, and the case where the set temperature is released and stored frozen, the set value is switched stepwise or continuously. This setting switching can be automatically switched to each preset temperature based on a time interval by a preset timer. However, it is also possible to manually switch the temperature to be set by providing a switch or the like on the liquid crystal panel 5 installed on the door of the refrigerator compartment 100. The temperature of the cooling chamber 200 from the supercooling state until the frozen storage is further detected by detecting the set temperature and the room temperature of a thermistor (not shown), or detecting the temperature of the food surface to set the damper. Controlled by the cool air adjusting means. Of course, an infrared sensor for measuring food temperature may be used in place of a thermistor for measuring room temperature to control a compressor, a damper, and the like.

  As described above, if the food is supercooled by the cold air introduced into the cooling chamber by setting the temperature of the freezing chamber or the cooling chamber at the first temperature setting with respect to the supercooling state, the temperature difference is next set in advance. The stored food is released from the supercooling state at a temperature difference lower than the first temperature, and when it is determined that the supercooling state is released from the food surface temperature state, The cool air is adjusted according to the third temperature set by the changeover switch. In this way, the first set temperature, the second set temperature, and the third set temperature are sequentially changed at intervals of time or by measuring the temperature of the food, so that the software stored in the microcomputer is simple. By adjusting the cool air with the structure, it is possible to perform frozen storage that can achieve high-quality food freezing with low energy without performing quick freezing or at extremely low temperatures such as −60 ° C. When setting the time interval, the time interval stored in advance may be used, or the time may be set by the liquid crystal panel 5 on the door surface. Thereby, a quick process is attained according to foodstuffs. Moreover, deepening of the degree of supercooling can be obtained by measuring the temperature of the food and determining the release.

  When the food to be stored is brought into a supercooled state, the temperature of the freezing chamber or the cooling chamber for storing the food is set at the temperature set as the setting means at the first temperature stored in the microcomputer. The amount of the cool air introduced into the cooling chamber set in the above is adjusted to enter a supercooling state, and this supercooling state is continued. Next, the supercooling state of the food is supplied by supplying cold air at a temperature lower than the first temperature so that the supercooling state of the food is released after the time set as the time necessary for the supercooling has elapsed. The state is released, and the released food is stored frozen at a third temperature set by a temperature setting device provided on the door surface. Assuming that the first temperature setting is stored in advance, the third temperature to be set can be easily switched manually, and can be set independently of each other. However, when setting the first temperature, a temperature setting device may be provided on the door surface of the refrigerator or the side surface of the cooling chamber so that it can be changed according to the type of food. The temperature setting state and the temperature state detected on the food surface can be displayed on the liquid crystal panel 5, and the set temperature can be changed while viewing the display. For the setting of the third temperature, considering long-term storage for several months or more, use a knife etc. with a deep temperate region of -30 ° C to -60 ° C or fine ice crystals of -5 ° C to -15 ° C. It is also possible to adopt a structure that can be switched to a weak refrigeration temperature range that can be separated by a person, or an intermediate frozen storage temperature range. When the temperature is set, the control device performs on / off control such as the rotation speed of the compressor and the opening / closing of the damper so that the temperature detected by the sensor is switched to the set temperature range. As described above, since the first set temperature and the third set temperature can be set independently of each other, the time required to maintain the necessary supercooling state according to the storage period and the use state, or according to the time and the type of food to be stored. Since the set temperature can be changed according to the depth of supercooling, flexible frozen storage is possible.

  Also, when setting the temperature of the cooling chamber for indirect cooling, the room temperature was measured with a sensor provided in the cooling chamber or estimated from the elapsed time of the room temperature of the wall to be cooled, and the food was set as an overcooled state It can be determined whether the first temperature is reached. It is possible to release the supercooling by lowering the temperature of the cold air indirectly cooled to a temperature lower than the first temperature at which the food stored in the cooling chamber is brought into a supercooled state to lower the wall surface temperature. Alternatively, the supercooling may be canceled by increasing the rotational speed of the blower fan in the sealed cooling chamber to increase the wind speed around the food to increase the heat transfer coefficient of the food surface. The more the temperature distribution on the surface of the food becomes uneven, the easier the supercooling is released. Open the cooling chamber released by the supercooling state release means for releasing the supercooled state of the food, and store the food in the frozen state with the cold air introduced directly into the room, or set the temperature of the wall surface with indirect cooling. The food in the room may be stored frozen by lowering or maintaining it. In this way, it can be frozen and stored with low energy with a simple structure.

  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 41a for adjusting the distribution of cool air to the switching chamber rear upper air outlet 42 and the switching chamber ceiling air outlet 43 on the front side of the ceiling surface is disposed in the switching chamber air passage 41. Depending on the opening / closing angle of the damper 46, 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 at the back of the ceiling surface 96, for example, when the air outlet 43 is on the front side of the ceiling surface 96 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 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 cooling chamber in which the food to be stored is supercooled, that is, 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. In addition, the cold air temperature rises by increasing the distance passing through the air passage 41, the cold air temperature from the outlet 43 becomes higher than the cold air flowing in from the outlet 42 near the damper 46, and the food surface is rapidly cooled. There is no effect. The switching chamber set temperature at that time is set higher than the normal freezing chamber set temperature. Cooling is performed as described above until the core temperature reaches the freezing point, and if it is determined that the surface temperature has reached the freezing point, it is rapidly cooled so as to lower the minimum point of 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. Note that even in an environment where the wind speed is low, such as natural convection, the supercooling 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 switching room is used in refrigeration setting, cooling speed cannot be obtained by natural convection, but rapid cooling is possible when direct cooling air is introduced as in this embodiment, and more time intervals By setting the maintenance or release of the supercooled state in, the supercooled freezing time can be shortened and the freezing quality can be improved, and the supercooled freezing space is used effectively and the cooling room is supercooled. A wider range of use is possible, such as mixing with non-food. 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 non-uniformity caused by direct blowing of cold air may cause overcooling, a part of or all of the lid may use a member with good thermal conductivity, and the number of outlets The position, the shape of the outlet, and the positional relationship between the outlet and the lid may fall within a predetermined temperature unevenness range. The predetermined temperature unevenness range is within 10K, preferably within 5K, and more preferably within 2K.

  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. Furthermore, the case where a heat storage agent capable of absorbing the heat capacity of food is provided leads to further shortening of the supercooling and freezing time.

  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. If the temperature of the cooling chamber is continuously lowered so as to deepen the supercooling state as already described, the probability of automatically releasing the supercooling increases, for example, when the temperature is lowered below −10 ° C. When this automatic release occurs, the food temperature rises and can be distinguished. When this automatic release or forced release occurs, the release time should be confirmed by measuring with a sensor. The determination of the supercooling release timing can 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 can detect a change in the surface temperature of the food. It is ready to know the release by this change. Furthermore, the core temperature of the food is calculated from the detected surface temperature, and the calculated core temperature of the food is the temperature indicated by the above-described supercooling condition, and the temperature that is preset and stored in the microcomputer or the like When it is judged that the temperature has reached the value, it is possible to add a stimulus for canceling the supercooling. This makes it possible to shorten the time of the supercooled state. Of course, the difference between the surface temperature and the core temperature may be small, and even if the set control time interval reaches the time to cancel, priority is given to determining that the temperature difference is small, and the cooling temperature is further increased. It is also possible to deepen the degree of supercooling by lowering. As described above, the use of the surface temperature measurement facilitates complicated determination.

  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 release.

  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 release.

  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 canceling 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.

  In addition, although the case where the supercooling space as a cooling room is in the switching room 200 has been described, the supercooling space is located in any part of the refrigerating room 100, the freezing room 300, the vegetable room 400, and the ice making room 500 of the refrigerator in FIG. It may be provided. 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. Also, the structure of the refrigerator for home use has been explained mainly, but the idea of the present invention is also applied to a large cryogenic commercial freezer warehouse. On the other hand, cooling is performed to maintain supercooling while gradually lowering the temperature by using an air flow with good distribution at a high freezing temperature, and after a predetermined time, a lower temperature is directly sprayed on the food to quickly freeze and release the supercooling. After that, it is possible to employ a configuration utilizing control of storing at a temperature lower than the temperature at which the supercooled state is obtained, for example, a freezing temperature of about −18 ° C. As a result, significant energy savings can be achieved. In addition, it is effective to enter a supercooled state while transporting food in a low temperature transport vehicle as a refrigerator, maintain the supercooled state, supply cooler air directly to the food and release the supercooling, Can be stored frozen. That is, in the case of meat or fish, since each cell and the cells are filled with moisture without any gaps, it corresponds to a container filled with water without any gaps, so there is no release of supercooling due to vibration during transportation, and Store food at room temperature, cool at a temperature that is not too low, and finally freeze it at an extremely low temperature such as -60 ° C as in a commercial freezer. Therefore, energy is not used as a transport vehicle, and it is also useful for energy saving before and after transport, such as supercooled refrigeration using transport time, and food with good freezing quality can be delivered to the delivery destination.

  In addition, since the food that has been supercooled and frozen in the refrigerator of the present invention has a slow cooling rate when creating a supercooled state, ice crystals begin to form at the same time after the temperature has dropped uniformly to the inside of the food, and in part The generated ice crystals 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.

  The refrigerator of the present invention blows out food stored by the cold air circulating from the cooler continuously from the freezing temperature zone to 0 ° C. or a temperature range of the freezing temperature, or from the cold air outlet of the freezing room. Frozen air is sucked into the cooler and the food is stored in a freezer that keeps the food in a supercooled state that does not freeze even at temperatures below the freezing point. A temperature setting means for setting the temperature of the chamber to −15 ° C. or lower and −15 ° C. or higher; Since it is provided with a cold air adjusting means for adjusting the cold air taken into the cooling chamber, high-quality refrigeration can be realized with energy saving.

  The refrigerator of the present invention is a supercooling state in which a freezer that freezes food stored by cold air from a cooler and cold air that is blown out from the cold air outlet of the freezer and sucked into the cooler does not freeze even at temperatures below the freezing point The cooling chamber is arranged in a freezing chamber for maintaining food stored in the storage room, and the cooling chamber is constituted by a lower case covered by an upper case arranged in the freezing chamber, and between the upper case and the lower case. Provided with a gap for taking in cold air, and the gap is an opening facing in a direction different from the flow direction of the cold air flowing through the freezer compartment, and the gap has a size of about 10-30 mm. Quality refrigeration can be realized.

  The refrigerator of the present invention includes a supercooling chamber that keeps food stored by cold air from the cooler in a supercooled state that is not frozen at a set temperature of −15 ° C. or lower below the freezing point, and a supercooled chamber that is blown into the supercooled chamber. The cold air adjusting means for changing the temperature of the cold air circulating in the air, and the food which is stored in the supercooling chamber by the cold air adjusting means and which is in a supercooled state is supplied with cold air having a temperature about 2 to 5 degrees lower than the set temperature. And a supercooling canceling means for canceling the supercooling state, it is possible to easily obtain a high quality frozen food.

  The temperature setting means for setting the temperature of the freezing chamber or the cooling chamber according to the present invention is a cooling in a range where the surface temperature of the food decreases from 3 ° C. to 0 ° C. when the normal temperature food stored in the cooling chamber is cooled. Since the speed is in the range of −3.5 ° C./hr to −10 ° C./hr, it is possible to reliably enter the supercooled state.

  A cold air outlet for blowing cold air into the freezing or cooling chamber of the present invention, an intake port for taking cold air into the cooling chamber, and a cold air adjusting means for adjusting the cold air to at least one of the air passages between the cold air outlet and the intake port It is possible to maintain the supercooled state by adjusting the cool air by the cool air adjusting means and suppressing the wind speed around the food that becomes supercooled to about 0.1 to 0.5 m / s.

  The cold air adjusting means of the present invention is configured such that the air path between the cold air outlet and the intake port is bent a plurality of times or provided with an air path length corresponding to the depth of the cooling chamber, or the cold air adjusting means includes a damper. The air velocity at the cold air outlet of the cold air blown out to the freezing chamber or the cooling chamber is suppressed to about 1.0 to 1.2 m / s, thereby maintaining a supercooled state.

  The temperature setting means for setting the temperature of the freezing room or the cooling room according to the present invention is such that the temperature of the freezing room or the cooling room is set to a freezing temperature zone of −17 degrees or more below the freezing point of the food and the temperature of the food is the freezing point When the temperature falls below a preset temperature or when a predetermined time has elapsed since the food is stored in the cooling room, the freezing room temperature is lowered by about 1-2 degrees so as to deepen the supercooled state of the food. So you can improve the frozen quality of food.

  When the stored food is brought into a supercooled state, the cold air adjusting means of the present invention adjusts the fluctuation range due to the cooling state change of the air temperature around the food to be within 10 degrees, or the air temperature inside the cooling chamber Since the unevenness is adjusted to be within 2 degrees, the supercooled state can be maintained.

  After the food of the present invention has been stored, a rapid change in the temperature of the food is detected or the food in the freezing room or the cooling room is subjected to a physical impact such as temperature, vibration, or ultrasonic wave to release the supercooling and set in advance. Since the food is stored at a frozen temperature or rapidly frozen, the frozen quality of the food can be improved. This overcooling cancellation can be easily performed because it is performed by directly introducing cool air into the cooling chamber.

  The cryopreservation method of the present invention includes a cooling chamber that keeps food stored by cold air from a cooler in a supercooled state that is not frozen at a set temperature of −15 ° C. or lower below the freezing point, and a blowout chamber that is blown into the cooling chamber. A step of storing food in a cooling chamber set at -15 ° C or higher, and the temperature in the cooling chamber is -10 by the cold air adjusting means. A step of adjusting for a certain period of time so that the air velocity in the cooling chamber is 0.5 m / s or lower, or cold air at a temperature 2 to 5 degrees lower than the set temperature in the supercooled food housed in the cooling chamber In the case of a refrigerator for a vehicle such as a refrigerated vehicle, it takes a long time to carry it during transportation or when it is necessary to reduce energy consumption. In it it is possible to a variety of business systems, such as it is possible to provide a good frozen food quality to the destination.

  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.

  The refrigerator of the present invention includes a first temperature setting unit that sets the temperature of the cooling chamber and sets the food in a supercooled state by the cold air introduced into the cooling chamber, and the cooling chamber set by the first temperature setting unit. A second temperature setting means for releasing the supercooled state of the food at a temperature lower than the temperature; and a third temperature setting means for freezing and storing the food after the supercooled state is released. Since the temperature set by the setting means, the second temperature setting means, and the third temperature setting means is sequentially changed at time intervals or by measuring the temperature of the food, it can be stored in a frozen state with a simple structure and low energy. Is possible.

  The refrigerator of the present invention sets the temperature of the cooling chamber and sets the temperature of the cooling chamber set by the first temperature setting means for setting the food in a supercooled state by the cold air introduced into the cooling chamber, and the first temperature setting means. A supercooling state canceling means for canceling the supercooling state of the food with cold air at a lower temperature, and a third temperature setting means for storing the food released by the supercooling state canceling means in a frozen state, Since the temperature of the cooling chamber set by the temperature setting means can be set irrespective of the temperature of the cooling chamber set by the first temperature setting means, flexible frozen storage is possible.

  The refrigerator of the present invention has a first temperature setting means for setting the temperature of the cooling chamber and setting the food in a supercooled state by the cooled wall surface of the cooling chamber, and cold air for setting the food introduced into the cooling chamber in a supercooled state. Introduced into the cooling chamber that was released by the supercooling state release means and the supercooling state release means to release the supercooled state of the food by introducing cold air at a temperature lower than or faster than the temperature of the food or the wind speed around the food Since the third temperature setting means for storing the food in cold air is provided, the frozen structure can be stored with a simple structure and low energy.

And a temperature setting means for setting the temperature of the cooling chamber set by the third temperature setting means of the present invention so that the temperature can be changed. can get.

  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 of 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 refrigerator and freezing storage method according to the present invention can not only realize high-quality freezing with low energy in a household refrigerator, but also can be stored frozen for a long time without destroying cells with a simple structure and control. It is expected to be useful in a wide range of fields, such as large-scale long-term meat storage in the sea, frozen storage of fishery products from the ocean, etc.

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. 2 is a structural diagram of a supercooling case in 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. FIG. 6 shows a display panel of a refrigerator in Embodiment 1.

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, 16 control device, 41 switching room air path, 41a partition wall , 42 Switching room rear upper side outlet, 43 Switching room ceiling side outlet, 44 Switching room rear lower side outlet, 45 Switching room bottom inlet, 46 Damper, 50 Switching room ceiling surface duct, 51 Switching room ceiling surface duct Hole, 60 Switching chamber lid, 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 the back of switching case 91, slit in front of switching case, 95 surface temperature measuring device, 96 ceiling surface, 100 refrigerator compartment, 200 switching room, 201 switching case, 202 supercooling case 300 freezer room, 301 freezer case, 400 vegetable room, 401 vegetable case, 500 ice making room.

Claims (11)

  A first temperature setting means for setting the temperature of the cooling chamber to bring the food into a supercooled state by the cold air introduced into the cooling chamber; and a temperature lower than the temperature of the cooling chamber set by the first temperature setting means And a third temperature setting means for setting the food, which has been released from the supercooled state of the food by cold air, to a temperature at which the food is frozen and stored, and the cooling chamber set by the third temperature setting means The temperature of can be set regardless of the temperature of the cooling chamber set by the first temperature setting means.   A freezer that freezes food stored by cool air from the cooler, and cool air that is blown out from the cool air outlet of the freezer and sucked into the cooler is stored in a supercooled state that does not freeze even at temperatures below the freezing point. A cooling chamber arranged in the freezer compartment for maintaining food, and the cooling chamber is constituted by a lid arranged in the freezer compartment or a supercooling case covered by an upper case, and the lid or upper case and the supercooling case A gap for taking in the cool air provided between the case and the case. The gap is an opening facing a direction different from the flow direction of the cool air flowing through the freezer compartment, and the gap has a size of about 10 to 30 mm. A refrigerator characterized by that.   A cold air outlet that blows out cold air to the cooling chamber, an intake port that takes in cold air into the cooling chamber, and a cold air adjusting means that adjusts the cold air to at least one of the air path between the cold air outlet and the intake port, The refrigerator according to claim 1 or 2, wherein the cool air is adjusted by the cool air adjusting means, and the wind speed around the food in a supercooled state is suppressed to about 0.1 to 0.5 m / s.   4. The cold air adjusting means is configured such that the air path between the cold air outlet and the intake port is bent a plurality of times or provided with an air path length corresponding to the depth of the cooling chamber. Refrigerator.   A cold air adjusting means for adjusting the cold air is provided at the cold air outlet for blowing the cold air to the freezing chamber or the cooling chamber, and the cold air adjusting means is configured to discharge the cold air that is blown out to the freezing chamber or the cooling chamber by a damper. The refrigerator according to claim 1 or 2, wherein the wind speed at the mouth is suppressed to about 1.0 to 1.2 m / s.   A cold air adjusting means for changing the temperature of the cold air blown into the cooling chamber and circulating in the cooling chamber, and food that is stored in the cooling chamber by the cold air adjusting means and is in a supercooled state is 2 to 5 degrees from the set temperature The refrigerator according to claim 1, further comprising a supercooling release unit that supplies cold air at a temperature that is about a low temperature to release the supercooled state of the food.   The refrigerator according to claim 1, further comprising a food temperature measuring unit configured to measure a temperature of the food provided and stored in the cooling chamber. The temperature setting means for setting the temperature of the freezing chamber or the cooling chamber is such that the temperature of the freezing chamber or the cooling chamber set in a freezing temperature range of −17 degrees or more below the freezing point of the food is the temperature of the food. when the preset or if the food product becomes a temperature below the freezing point of a predetermined time has passed since the stored in the cooling chamber, the freezing chamber so as to lower the temperature reached a supercooled state of the food or 8. The refrigerator according to claim 1, wherein the set temperature of the cooling chamber is lowered by about 1-2 degrees.   The said cold air adjustment means adjusts so that the fluctuation | variation range by the cooling state change of the air temperature around the said foodstuff may be within 10 degree | times when the stored foodstuff is made into a supercooled state. The refrigerator according to 4 or 5.   The refrigerator according to claim 3, 4, or 5, wherein the cold air adjusting unit adjusts the air temperature unevenness in the supercooled chamber to be within 2 degrees.   Second temperature setting means for forcibly releasing the supercooled state of the food by supplying cold air having a temperature lower than the temperature of the cooling chamber set by the first temperature setting means, The refrigerator according to claim 1, wherein the temperature set by the temperature setting means, the second temperature setting means, and the third temperature setting means is switched based on a preset time interval.

Images