Freezing and thawing refrigerator and use method therefor

Abstract

To provide a freezing and thawing refrigerator having a function capable of preventing quality deterioration even in long-term storage.SOLUTION: A freezing and thawing refrigerator having functions of freezing food, storing frozen food, and thawing frozen food, comprises: a pre-freezing treatment chamber 15 in which food is pre-treated and controlled to a predetermined pre-freezing treatment temperature; a freezing chamber 17 in which food treated in the pre-freezing treatment chamber is frozen and controlled to a predetermined freezing temperature; a storage chamber 19 in which frozen food frozen in the freezing chamber is stored and controlled to a predetermined storage temperature; and a thawing chamber 21 in which frozen food is thawed and controlled to a predetermined thawing temperature.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a freezer capable of suppressing deterioration in food quality and smoothly performing freezing, storage, and thawing of frozen foods, and a method for using the same.

Background Art

[0002] The method of freezing and storing food can significantly extend the shelf life of food because it can minimize the loss of nutritional components of food and prevent the growth of harmful microorganisms (for example, Non-Patent Documents 1 to 3). This greatest feature of the long-term storage stability of frozen food enables not only a safe and rich daily diet but also the worldwide transportation of processed foods and fresh agricultural and fishery products, and allows people around the world to eat a variety of foods with confidence. Also, from the perspective of promoting the Japanese agricultural, forestry, and fishery industries, it is a preservation method that can greatly contribute to strengthening the export of the agricultural, forestry, and fishery industries.

[0003] And frozen storage gives rise to a dream-like event that modern people might be able to eat food frozen during the Ice Age. However, in order to enjoy frozen food deliciously, the food after thawing needs to maintain the quality of the food before freezing, and frozen storage cannot be regarded as a simple fairy tale, and biochemical and biophysical expertise is required. This is the freezing technology.

[0004] Freezing technology is composed of technology for suppressing quality deterioration occurring in the freezing process, storage process, and thawing process of food, and pretreatment technology for processing food before freezing that complements the suppression of quality deterioration in each process. The factors of quality deterioration and quality retention occurring in each process, as well as their generation mechanisms, are estimated by advanced analysis and evaluation technology, and solutions and promotion measures are taken. Hereinafter, the status of each technology will be described. Since the pretreatment technology is involved in each of freezing, storage, and thawing, it will be mainly described centering on freezing technology, storage technology, and thawing technology.

[0005] First, it has been found that the deterioration of the quality of frozen foods is deeply related to the ice crystals generated in the food during the freezing process. In order to suppress the quality deterioration, it is preferable to minimize the generation and growth of ice crystals. For this purpose, a rapid freezing technology that quickly passes through the temperature range of about -1 to -5 °C, which is called the maximum ice crystal formation zone, is required, and various technological developments have been made.

[0006] The challenges of this technological development mainly lie in the selection of the heat transfer medium for freezing the food, the improvement of the thermal conductivity of the food and the heat transfer medium, and the elimination of factors that promote or inhibit the formation of ice crystals. For example, as the heat transfer medium, in a refrigerator, the air blast method of blowing cold air is used, but it is preferable to use a liquid with better thermal conductivity than a gas, and the brine freezing method using an antifreeze has been adopted in the fishery and livestock processing industries. Furthermore, the heat transfer efficiency is enhanced by the flow of the antifreeze and the pretreatment of thinly and finely cutting to increase the contact area between the food and the heat transfer medium. However, in general household refrigerators and freezers, only those using a gas as the heat transfer medium are available.

[0007] On the other hand, the use of ultrasonic waves and antifreeze proteins that promote or inhibit the formation of ice crystals, the use of dehydration freezing, and the use of high pressure that lowers the freezing point have been extensively studied, but there are still many unclear points in these effects and mechanisms, and it seems that they have not yet reached practical use. In addition, in general households, there remains the problem that substances with complex structures and difficult to obtain must be used.

[0008] It has been found that the quality deterioration during the storage process is caused by the recrystallization and coarsening of ice crystals inside the frozen food, the drying of the surface of the frozen food and the accompanying deterioration such as oxidation, discoloration, and off-odor, and the chemical reactions occurring in the frozen food.

[0009] Regarding the recrystallization and coarsening of ice crystals, since it is based on the aggregation of ice crystals, in order to suppress the molecular mobility of water, it is preferable to set the temperature lower than about -18 °C in the freezer of the refrigerator. However, in general households, it is stored in a freezer at about -18 °C.

[0010] The problem of drying is inevitably caused by the fact that frozen foods with a saturated water vapor pressure of ice are stored in a dry atmosphere with a low water vapor pressure, such as the freezer compartment of a refrigerator. In contrast, in the fishery and livestock processing industries, a method called glazing treatment, which forms a thin ice protection layer on the surface of frozen foods, is widely used to block the dry atmosphere. However, in ordinary households, as a simple method, it is common for frozen foods packaged in plastic bags or the like to be stored in the freezer. However, it is preferable to carry out packaging with as little space as possible so as to reduce contact with the dry atmosphere.

[0011] And the problem of chemical reactions occurs because the molecular motion of components such as pigments and enzymes that make up foods other than ice crystals is not completely frozen. The chemical reaction of pigments is mainly discoloration due to oxidation and can be suppressed by storing at a lower temperature. Also, blocking oxygen by glazing treatment or packaging also has the effect of suppressing discoloration. Regarding the reaction of enzymes, a heat pretreatment called blanching, with the inactivation of heat-resistant peroxidase and catalase as a reference, is effective. It is often carried out on vegetables that dislike discoloration and is often treated with boiling water for several minutes. Also, blanching is considered an effective method for foods that are cooked with heating after thawing because it forms a protective film of heat-denatured protein on the surface of fishery and livestock products as well. In particular, glazing treatment is preferable for suppressing chemical reactions of fishery and livestock products, but it is not easy to carry out in ordinary households.

[0012] Quality deterioration during thawing, similar to the freezing process, occurs because frozen foods pass through the maximum ice crystal formation zone during thawing, and the generation and growth of ice crystals that occur while melting cause quality deterioration that destroys the food's tissue. Moreover, during thawing, heat is applied, which is the opposite of the freezing process, leading to quality deterioration due to enzyme reactions, microbial control, and heat. Therefore, thawing has the difficult problem of reconciling the conflicting requirements of having to be done rapidly and at low temperature. Thus, thawing frozen foods with low thermal conductivity, especially large, block-shaped frozen foods, at low temperatures requires significantly more time than freezing. For this reason, it is preferable to perform a pretreatment of thinly and finely cutting the food to increase the contact area between the food and the heat transfer medium. However, even in this case, it is not easy to shorten the thawing time. Also, in the case of foods to be cooked by heat processing or the like, the temperature of the heat transfer medium can be increased. However, in the case of raw foods for consumption, as well as aquatic and livestock products that need to be shaped and cooked after thawing, they cannot be exposed to high temperatures. Therefore, thawing to return to high-quality food needs to be carried out according to the type of food, cooking method, etc., requires delicate techniques, and it has been extremely difficult to establish a general-purpose thawing technique.

[0013] Under these circumstances, as methods using a heat transfer medium, a steam thawing method that utilizes the latent heat of condensation of steam (for example, Patent Document 1), a low-temperature water thawing method at about 0°C, and a dielectric heating thawing method that utilizes microwaves or high frequencies have been put into practical use in the aquatic product processing industry and the livestock product processing industry. In particular, the dielectric heating method can thaw from the inside of frozen foods, so it has been widely put into practical use, and it has been reported that dielectric heating thawing using electromagnetic waves is effective for sea urchins and salmon roe (Patent Document 2). For this reason, many technologies for introducing this dielectric heating method into refrigerators have been proposed (for example, Patent Document 3). However, the dielectric heating method requires a magnetron and electronic circuits, and the structure becomes complex. Therefore, such refrigerators have not been manufactured and sold, and in general households, low-temperature thawing at about 5 to 10°C in the refrigerator compartment or natural thawing at room temperature are often performed.

[0014] Furthermore, similar to the freezing technology using high pressure, thawing using the phenomenon of the freezing point dropping under high pressure, thawing in a high-voltage field, etc. have been reported, but it is considered that they have not reached the stage of practical application.

[0015] Thus, it is no exaggeration to say that freezing technology has revolutionized the world's diet and is an extremely important technology. Therefore, in the fishery and livestock processing industries, it has surely evolved. However, there are numerous problems to be solved and further development is necessary. In particular, as an effective freezing technology for general households, the dielectric heating thawing method using a microwave oven can be cited. However, as described above, rapid freezing and rapid thawing technologies are not sufficiently reflected, and it only stops at freezing and thawing by temperature control of the refrigerator (for example, Patent Documents 4 and 5).

Prior Art Documents

Patent Documents

[0016]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Non-Patent Documents

[0017]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0018] As described in the background art, refrigeration technology has been steadily advancing. In the seafood and livestock processing industries, the developed refrigeration technology has been put into practical use, and frozen foods of fresh seafood and livestock products are now available all over the world without causing quality degradation. However, there is no refrigerator on the market that utilizes refrigeration technology and has rapid freezing and rapid thawing functions, allowing ordinary households to handle frozen foods of fresh seafood and livestock products.

[0019] Currently, most refrigerators are equipped with a freezer that can store food for about a month, which is a characteristic of frozen storage. However, since they do not have an appropriate thawing function, fresh seafood and livestock products such as fish and meat are stored at a precise temperature just below freezing, around -1 to -3°C, creating a partial freezing layer on their surfaces to prevent oxidation. These refrigerators also have a partial function to maintain freshness at a temperature just before freezing, around 0 to 2°C, for foods between the partial freezing area and the refrigerator compartment. As a result, short-term storage of about 3 to 7 days is possible, eliminating the need for thawing and allowing for proper usage according to the storage purpose and type of food (for example, see Non-Patent Document 4). Additionally, these refrigerators are equipped with functions to maintain freshness through high-humidity and low-temperature storage for fresh agricultural products such as vegetables, various computer (AI) control functions, and wireless control functions (for example, see Non-Patent Document 5).

[0020] Therefore, an object of the present invention is to provide a refrigeration and thawing refrigerator that utilizes the refrigeration technology employed in the seafood and livestock processing industries, enabling easy freezing, storage, and thawing of fresh seafood and livestock products in ordinary households. In particular, it is an object of the present invention to provide a refrigeration and thawing refrigerator having a function capable of suppressing quality degradation of frozen foods due to rapid freezing and rapid thawing and preventing quality degradation even during long-term storage. Furthermore, the present invention provides a method of using the refrigeration and thawing refrigerator of the present invention to further suppress quality degradation of frozen foods. By means of the present invention, in ordinary households, it is possible to realize a lifestyle in which the freshness, flavor, color, etc. at the time of purchase can be enjoyed over a long period by maintaining the quality of fresh seafood and livestock products through frozen storage.

Means for Solving the Problems

[0021] The inventor has noticed that in a refrigerator in a general household, since freezing, storage, and thawing are performed by the contact between food and gas, it is difficult to perform rapid freezing and rapid thawing, and quality degradation occurs due to drying during storage, frost formation, and discoloration due to oxidation, etc. That is, the refrigeration technology in general households using gas as a medium is the cause of such adverse effects. To eliminate this, a refrigeration technology using a liquid in which food and liquid are in contact as a medium is required, and the inventor has started developing a refrigerator that can perform freezing, storage, and thawing using a liquid as a medium even in a general household. As a result, the inventor has found that it is possible to provide a refrigerating and thawing refrigerator having a function of suppressing the quality degradation of frozen food and preventing quality degradation even during long-term storage, and has completed the present invention.

[0022] That is, the present invention is a refrigerating and thawing refrigerator having a function of freezing food, a function of storing frozen food, and a function of thawing frozen food, wherein a pre-freezing treatment of food is performed, and a pre-freezing treatment chamber controlled to a pre-freezing treatment temperature of about 2 to 5°C, freezing of the food treated in the pre-freezing treatment chamber is performed, and a freezing chamber controlled to a freezing temperature of about -40 to -20°C, storage of the frozen food frozen in the freezing chamber is performed, and a storage chamber controlled to a storage temperature of about -40 to -18°C, and thawing of the frozen food is performed, and a thawing chamber controlled to a thawing temperature of about -5 to 0°C.

[0023] Thus, by performing a pre-treatment at a pre-freezing treatment temperature of about 2 to 5°C before freezing in the freezing chamber, the freezing time is shortened, and the temperature range of about -1 to -5°C, which is called the maximum ice crystal formation zone, can be quickly passed through. Therefore, the formation and growth of ice crystals generated in the food can be minimized, and the quality degradation due to freezing can be suppressed.

[0024] Also, by setting the storage temperature to approximately -40 to -18°C, the molecular mobility of frozen foods can be reduced compared to the freezer of a general refrigerator, and ice recrystallization, coarsening, and chemical reactions can be suppressed, thereby suppressing quality degradation during long-term storage of frozen foods. The lower the storage temperature, the better. However, due to long-term operation, there is also an issue of energy consumption. Therefore, a temperature range of approximately -40 to -18°C is preferred, more preferably approximately -40 to -20°C, and even more preferably approximately -40 to -30°C.

[0025] Furthermore, by using a refrigerant for controlling the freezing temperature of the freezer compartment that is a liquid having a thermal conductivity approximately 20 times that of the gas, the freezing rate in the freezer compartment controlled to a freezing temperature of approximately -40 to -20°C can be increased, and quality degradation due to freezing can be more effectively prevented.

[0026] Also, in the freezing technology, especially during thawing that causes quality degradation of frozen foods, during freezing, it is preferable that the refrigerant for controlling the thawing temperature of the thawing compartment is a liquid and is controlled to approximately -5 to 0°C, more preferably approximately -5 to -2°C. By using a refrigerant with a high thermal conductivity in this way, similar to the freezing process, during the thawing process when the frozen food passes through the maximum ice crystal formation zone, the generation and growth of ice crystals that occur while melting can be suppressed, and quality degradation that destroys the food tissue can be prevented.

[0027] Moreover, heat is not added compared to steam thawing methods or low-temperature water thawing methods that use the same electric heating medium, and quality degradation due to enzyme reactions, microbial control, and heat can be suppressed. Therefore, it is possible to achieve the coexistence of the conflicting processes of thawing that must be performed rapidly and at a low temperature. And, like the dielectric heating thawing method using microwaves or high frequencies that has been put into practical use in the fishery and livestock processing industries, a magnetron and electronic circuits are not required, and the structure does not become complicated. Therefore, the same gas compression method as the cooling method of a general household refrigerator can be used, and it is easy to incorporate the thawing compartment of the present invention into a household refrigerator.

[0028] In addition to the refrigerant that controls the freezing and thawing temperatures, it is more preferable that the refrigerant that controls the pre-freezing treatment temperature is a liquid, because the time required for the pre-freezing treatment is shortened, and the time required for the entire freezing process including the pre-freezing treatment and freezing can be shortened.

[0029] Although different from the effects exerted by the element of such speed, in addition to the refrigerant that controls the freezing and thawing temperatures, it is also preferable to make the refrigerant that controls the storage temperature of about -40 to -18°C a liquid. It has been found that the quality deterioration during the storage process is due to the recrystallization and coarsening of ice crystals inside the frozen food, the drying of the surface of the frozen food and the accompanying oxidation, discoloration, and deterioration such as abnormal odor, and the chemical reactions occurring within the frozen food. The recrystallization and coarsening of ice crystals inside the frozen food have a strong relationship with the storage temperature, and the drying of the surface of the frozen food and the accompanying oxidation, discoloration, and deterioration such as abnormal odor, and the chemical reactions occurring within the frozen food have a strong relationship with the contact with the cold air containing oxygen. Blocking with the cold air such as glazing treatment, packaging, and blanching is effective. That is, it is preferable to make the refrigerant that controls the storage temperature a liquid because by making the refrigerant a liquid, the frozen food and the cold air can be blocked, and these quality deterioration factors can be eliminated.

[0030] Therefore, it is preferable to perform at least freezing and thawing with a liquid refrigerant. Furthermore, it is more preferable to perform pre-freezing treatment and / or storage with a liquid refrigerant.

[0031] Furthermore, the freeze-thaw refrigerator of the present invention is a refrigerator that makes full use of freezing technologies such as freezing, storage, and thawing. However, in order to store the food to be frozen, it is preferable to be provided with a refrigerating chamber whose temperature is controlled to about 3 to 6°C.

[0032] As described above, in the freezing and thawing refrigerator of the present invention, it is not always necessary to use a liquid as the refrigerant. However, when using a liquid as the refrigerant, it is preferable to use an antifreeze used in the brine freezing method as the liquid. This antifreeze is an aqueous liquid mainly composed of a monohydric to trihydric alcohol such as alcohol, ethylene glycol, propylene glycol, glycerin, etc., and by utilizing the freezing point depression of water, a liquid that does not freeze down to about -45°C can be used. For example, an antifreeze suitable for pre-freezing treatment, freezing, storage, and thawing, corresponding to the Aurora Brine (registered trademark) series (F, P, PS, RH, and TS) manufactured by Tokyo Fine Chemical Co., Ltd., and Shadan and Sleeve Brine manufactured by Sanwa Oil Chemical Co., Ltd., can be selected and used. However, it is preferable that the antifreeze used in the present invention does not contain a rust inhibitor.

[0033] When using this antifreeze, a treatment tank for immersing food and frozen food in each chamber is provided, filled with the antifreeze therein, and the frozen food placed in a basket such as a stainless steel mesh or stainless steel wire is put into the treatment tank for each treatment to be performed. This treatment tank preferably has an inner wall formed of a metal such as stainless steel with high thermal conductivity, its side wall is surrounded by a heat insulating material, a cooler is arranged in contact with the bottom surface of the inner wall, and the cooler is embedded in a heat insulating bottom plate. As the heat insulating material, a heat insulating material generally used in a refrigerator can be used, but it is necessary to use a combination of a foamed heat insulating material and a vacuum heat insulating material, preferably a vacuum heat insulating material, to enhance the cold storage effect. In addition, in order to prevent floating when food and frozen food are put into the antifreeze, it is preferable to provide a lid and a weight on the basket.

[0034] And the method for cooling such antifreeze is not particularly limited, but it is preferable to use a cooling method used in refrigerators such as a gas compression method, a gas adsorption method, and a Peltier method. A gas compression type composed of a cycle of compression, condensation, and cooling, which has high cooling capacity and is used in general household refrigerators, is particularly preferable. When using a gas (air) as the refrigerant, in the case of a gas compression type with one cooler, the cold air generated by the cooler is shunted by a damper provided in the air duct leading to the pre-freezing chamber, the freezing chamber, the storage chamber, and the thawing chamber, and an indirect cooling type capable of controlling the temperature of each chamber can be adopted. When the refrigerant is a liquid, a direct cooling type in which coolers are installed for each of the pre-freezing chamber, the freezing chamber, the storage chamber, and the thawing chamber is preferable. In the case of a general household refrigerator, since it is a direct cooling type that controls the compressor by detecting the temperature with a temperature sensor in one of the chambers, it is difficult to control the temperature of each chamber. However, in the freezing and thawing refrigerator of the present invention, in order to accurately control the temperature of each chamber, it is preferable to provide a condenser shunted to the cooler or a condenser corresponding to the cooler, and to independently control the temperature of each chamber by the cooler by controlling the flow rate of the low-temperature liquid refrigerant generated by the condenser and conveyed to the cooler.

[0035] The freezing and thawing refrigerator of the present invention is a freezing and thawing refrigerator having a function of freezing food, a function of storing frozen food, and a function of thawing frozen food, in which pre-freezing treatment of food is performed and the pre-freezing treatment temperature is controlled to about 2 to 5 °C. A pre-freezing chamber, a freezing chamber where the food treated in the pre-freezing chamber is frozen and the freezing temperature is controlled to about -40 to -20 °C, a storage chamber where the frozen food frozen in the freezing chamber is stored and the storage temperature is controlled to about -40 to -18 °C, and a thawing chamber where the frozen food is thawed and the thawing temperature is controlled to about -5 to 0 °C. Therefore, in these temperature ranges, by appropriately setting the processing time and storage time according to the food packaged using a plastic film or the like and performing freezing, storage, and thawing, the quality of food, especially fresh aquatic and livestock products, will not deteriorate, and even after long-term frozen storage, the freshness, flavor, and color before freezing can be enjoyed by ordinary households.

[0036] Furthermore, by optimizing its usage method, the freeze-thaw refrigerator of the present invention can achieve an effect comparable to that of the freezing technology used in the fishery and livestock processing industries even in ordinary households. The usage method includes a freezing preparation step of cutting the food to a thickness of about 10.0 cm or less and packaging it with a sealable plastic film, a freezing pretreatment step in the freezing pretreatment chamber where the frozen food packaged in the freezing preparation step is subjected to low-temperature treatment for a predetermined time, a freezing step in the freezer where the frozen food that has undergone the freezing pretreatment step is subjected to freezing treatment for a predetermined time, a storage step in the storage chamber where the frozen food frozen in the freezing step is stored for a predetermined period, and a thawing step in the thawing chamber where the frozen food that has undergone the storage step is subjected to thawing treatment for a predetermined time. This usage method is particularly effective for fresh fishery and livestock products, and it has been found that the thickness has a significant impact, and the thinner the thickness is, the more preferable it is, preferably less than about 10.0 cm. However, if the thickness is 0.3 cm or less, when the amount of food to be frozen is large, it requires a great deal of labor for packaging. Therefore, a thickness of about 0.3 to 10.0 cm is more preferable, and a thickness of about 0.5 to 5.0 cm is even more preferable. However, this thickness means the minimum unit of the food to be frozen, that is, the thickness of one piece, and in the case of thin ones, it also includes the stacked thickness.

[0037] In addition, in the case of frozen foods, particularly fresh aquatic and livestock products, it is preferable to be packaged with a plastic film in the freezing preparation process in order to prevent drying and oxidation during storage. The packaging can be performed using a thin polyolefin film, Saran Wrap (registered trademark) of a polyvinyl chloride film, and Dip Lock (registered trademark) of an olefin film provided with a zipper, etc., but in particular, vacuum packaging is more preferable. As the device for vacuum packaging, a commercially available vacuum packaging machine can be used, but as the plastic film for packaging, a multilayer plastic film having heat sealability for sealing and oxygen barrier properties for preventing oxidation is preferable. The oxygen barrier properties can be imparted by an aluminum foil, a polyvinyl alcohol-based film, a metal vapor-deposited plastic film, a metal oxide vapor-deposited film, etc., but a polyvinyl alcohol-based film and a metal oxide vapor-deposited film that allow the contents to be visible and can be used in a microwave oven are preferable.

[0038] In addition to such a preparation process for frozen foods, using an antifreeze liquid as a refrigerant in the freezing and thawing processes can further prevent quality degradation in the freezing and thawing of fresh aquatic and livestock products. Furthermore, by using an antifreeze liquid as a refrigerant also in the pre-freezing treatment process and / or the storage process, quality degradation in freezing, storage, and thawing can be significantly prevented.

Advantages of the Invention

[0039] According to the present invention, also in ordinary households, quality degradation in each process of freezing, storing, and thawing foods, particularly fresh aquatic and livestock products, is suppressed, and the effect of maintaining the quality of fresh aquatic and livestock products is achieved. By freezing and storing, it is possible to realize a life in which the freshness, flavor, color tone, etc. at the time of purchase can be enjoyed over a long period.

Brief Description of the Drawings

[0040]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0041] Hereinafter, the refrigerating, thawing and freezing refrigerator of the present invention and its usage method will be specifically described using representative examples of embodiments. However, the present invention is not limited to the embodiments, and various modifications can be made without departing from the gist of the present invention and implemented, and it is limited only by the technical idea described in the claims.

[0042] FIG. 1 shows a front schematic view of a refrigerating, thawing and freezing refrigerator 1 according to an embodiment of the present invention. At the uppermost stage, a refrigerating chamber 1-1 is provided, and foods stored in the refrigerating chamber 1-1 are arranged from top to bottom in the order of the processes from freezing to thawing, with a pre-freezing chamber 1-2, a freezing chamber 1-3, a frozen food storage chamber 1-4, and a thawing chamber 1-5. Since the required times for these processes and storage need to be adjusted according to various factors such as the type and size of the food, a timer is provided. This timer may be configured to be utilized for manual operation of these process and storage times, or may be configured to control the operating time of a cooler described later from the setting of this timer.

[0043] Figure 2 shows a schematic cross-sectional view taken vertically perpendicular to the paper near the center in the front schematic view (Figure 1) of the refrigeration-freezing refrigerator 1 according to an embodiment of the present invention. The refrigeration-freezing refrigerator 1 in this embodiment is composed of a refrigerating chamber 1-1, a pre-freezing chamber 1-2, a freezing chamber 1-3, a frozen food storage chamber 1-4, and a thawing chamber 1-5. Each of them is kept cold by a heat-insulating housing 2, a refrigerating chamber door 12, a pre-freezing chamber door 14, a freezing chamber door 16, a frozen food storage chamber door 18, and a thawing chamber door 20, and a heat-insulating partition 3. It is stably installed on a support base 4 provided with adjusting legs 41 for maintaining the balance of the refrigeration-freezing refrigerator 1, and externally, it is no different from a general household refrigerator. Also, in this embodiment, the temperature control method of the refrigeration-freezing refrigerator 1 also uses a gas compression type composed of the same compression, condensation, and cooling cycles as those of a general household refrigerator, and is equipped with a compressor 5, a condenser 6, and a cooler 7. The refrigerant circulates through the high-temperature and high-pressure gaseous refrigerant pipe 8, the low-temperature liquid refrigerant pipe 9, and the low-pressure gaseous refrigerant pipe 10, so that the refrigerating chamber 1-1, the pre-freezing chamber 1-2, the freezing chamber 1-3, the frozen food storage chamber 1-4, and the thawing chamber 1-5 are each maintained at a predetermined temperature.

[0044] However, in this embodiment, all of the pre-freezing process, freezing process, frozen food storage, and thawing process are carried out using propylene glycol-based antifreeze liquids 155, 175, 195, and 215 that do not freeze at about -45 to 25 °C filled in the pre-freezing tank 15, the freezing tank 17, the frozen food storage tank 19, and the thawing tank 21, and only refrigeration is carried out using air. However, for the frozen food storage tank 19, air cooling is more convenient and preferable because there is no need to handle frozen foods and antifreeze liquids.

[0045] The pre-freezing treatment tank 15, the freezing treatment tank 17, the frozen product storage tank 19, and the thawing treatment tank 21 are each equipped with a pre-freezing treatment chamber cooler 72, a freezing treatment chamber cooler 73, a frozen product storage chamber cooler 74, and a thawing treatment chamber cooler 75, a stirrer 23, and a temperature sensor 24, and are filled with propylene glycol-based antifreeze liquids 155, 175, 195, and 215 that do not freeze at about -45 to 25°C. To rapidly cool this antifreeze liquid 155, 175, 195, 215 and maintain its temperature, the inner walls 151, 171, 191, 211 of each treatment tank 15, 17, 19, 21 are formed of stainless steel or the like, which is a material with good thermal conductivity, and are surrounded by heat-insulating side plates 152, 172, 192, 212 of vacuum heat-insulating material with good cold-insulating properties. Also, each cooler is also surrounded by the same heat-insulating bottom plate to form a cold-insulating structure. In addition, stirrers for equalizing the temperature of the antifreeze liquids 155, 175, 195, 215, and slide-type lids 154, 174, 194, 214 for preventing the scattering of the antifreeze liquids 155, 175, 195, 215 and the mixing of foreign substances and the like are provided.

[0046] Each of these treatment tanks 15, 17, 19, and 21 is temperature-controlled by a refrigerant that circulates through a compressor 5, a condenser 6, and each of the coolers 72, 73, 74, 75, and is controlled by a freezer-refrigerator temperature control unit 26 based on the temperature detected by a temperature sensor 24. For example, the high-temperature and high-pressure gaseous refrigerant whose state has been changed by the compressor 5 is conveyed to the condenser 6 via the high-temperature and high-pressure gaseous refrigerant pipe 8, and the low-temperature liquid refrigerant whose state has changed there is branched off to each cooler 7 via the low-temperature liquid refrigerant pipe 9. After that, the low-pressure gaseous refrigerant whose state has changed by cooling each of the treatment tanks 15, 17, 19, 21 is circulated to the compressor via the low-pressure gaseous refrigerant pipe 10. However, the freezer-refrigerator temperature control unit 26 adjusts the flow rate of the refrigerant conveyed to the compressor 6 and each cooler 7 to control the temperature of each of the treatment tanks 15, 17, 19, 21. In FIG. 2, the temperature is controlled by one compressor 5 and one condenser 6, but they may be provided for each of the treatment tanks 15, 17, 19, 21. Also, the drain generated by this cooling mechanism is conveyed and processed from the drain tray 111 to the evaporation tray 112 through the drain pipe 11. However, spare parts such as a dryer and a capillary tube of the refrigerant used in the conventional gas compression type cooling mechanism are omitted.

[0047] On the other hand, the refrigerating compartment 1-1 is not necessarily required, but it is preferably provided for temporarily storing frozen foods. In this embodiment, it has a shelf 3 and is arranged at the top. This refrigerating compartment 1-1 is temperature-controlled in the same way as a general refrigerator. Air cooled by the low-temperature liquid refrigerant that is controlled and branched off by the freezer-refrigerator temperature control unit 26 based on the temperature detected by the temperature sensor 24 is diffused by the fan 22 to control the temperature of the refrigerating compartment 1-1.

[0048] To explain the usage method of the freezer-refrigerator 1 according to an embodiment of the present invention as described above, FIG. 3 shows a cross-sectional schematic diagram (a) and a perspective schematic diagram (b) showing the main part of the thawing chamber 1-1 in FIGS. 1 and 2, and a perspective schematic diagram (c) of a basket for handling foods to be frozen, stored, and thawed.

[0049] Only the thermally conductive thawing tank inner wall 211, stirrer 23, and temperature sensor 24 that make up the thawing tank 21 shown in the cross-sectional schematic diagram (a) are excerpted and shown in the perspective schematic diagram (b) so that the thawing tank 21 can be visually understood. The thawing chamber door 20 with a door handle is fixed to the thawing tank 21 so that the thawing tank 21 can be pulled out. (Not shown) Slide rails are formed on the heat-insulating housing 2 and the heat-insulating side plate 212 of the thawing tank 21. Also, the stirrer 23 and the temperature sensor 24 are connected to the refrigeration thawing refrigerator temperature control unit 26 by (not shown) telescopic wiring.

[0050] And the frozen food to be thawed and vacuum-packed is preferably accommodated in the processing and storage basket 27 shown in Fig. 3(c) for thawing treatment, but is not limited thereto. Such a processing and storage basket 27 is preferably used in the same manner in pre-freezing treatment, freezing, and storage. In particular, when temperature control is performed with an antifreeze solution, it is desirable to provide a lid or weight on the basket to prevent the food and frozen food from floating. Also, when the food and frozen food are put into the antifreeze solution, the antifreeze solution may splash or overflow, so it is preferable to provide a drain port and a drain receiver.

[0051] Finally, Fig. 4 shows the form of the food for using the refrigeration thawing refrigerator of the present invention. This figure is a perspective view of a vacuum packaging machine that can form an appropriate food packaging form when performing freezing, storage, and thawing, and raw steak before freezing packaged using the same. It is a figure with the contrast reduced for easy viewing after binarizing the photographed photo.

[0052] Such a vacuum packaging machine is not limited to such a mechanism, and a commercially available one can be used. The film to be packaged has at least heat-sealability It is a figure with the contrast reduced for easy viewing after binarizing the photo.

[0053] Here, a raw steak with a thickness of about 3 to 4 cm is vacuum-packed using a plastic film having heat-sealing properties and oxygen barrier properties, and a preparation process is shown in which pre-freezing, freezing, storage, and thawing are performed.

Industrial Applicability

[0054] The freeze-thaw refrigerator of the present invention has a freezing technology at the same level as the freezing technology employed in operations such as the fishery processing industry and the livestock processing industry, and realizes freezing of foods, storage of the frozen foods, and thawing, which have been impossible with conventional general household refrigerators. In addition, in terms of appearance, it is comparable to a household refrigerator, and thus it will be widely popularized among general consumers. Moreover, due to its large size, it can also be used for business purposes, and its industrial applicability is extremely high.

Explanation of Signs

[0055] 1 Freeze-thaw refrigerator 1-1 Refrigerating chamber 1-2 Pre-freezing chamber 1-3 Freezing chamber 1-4 Frozen food storage chamber 1-5 Thawing chamber 2 Heat-insulating housing 3 Heat-insulating partition 4 Support base 41 Adjusting feet 5 Compressor 6 Condenser 7 Cooler 71 Refrigerating chamber cooler 72 Pre-freezing chamber cooler 73 Freezing chamber cooler 74 Frozen food storage chamber cooler 75 Thawing chamber cooler 8 High-temperature and high-pressure gaseous refrigerant pipe 9 Low-temperature liquid refrigerant pipe 91 Refrigerating chamber pipe 92 Pre-freezing chamber pipe 93 Freezing chamber pipe 94 Frozen food storage chamber pipe 95 Thawing chamber pipe 10 Low-pressure gaseous refrigerant pipe 11 Drain pipe 111 Drain pan 112 Evaporation dish 12 Refrigerator door 121 Door handle 122 Door pocket 13 Shelf 14 Freezing pretreatment chamber door 141 Door handle 15 Freezing pretreatment tank 151 Heat-conductive inner wall of freezing pretreatment tank 152 Heat-insulating side plate 153 Heat-insulating bottom plate 154 Slide-type cover 155 Freezing pretreatment antifreeze 16 Freezing treatment chamber door 161 Door handle 17 Freezing treatment tank 171 Heat-conductive inner wall of freezing treatment tank 172 Heat-insulating side plate 173 Heat-insulating bottom plate 174 Slide-type cover 175 Freezing treatment antifreeze 18 Frozen product storage chamber door 181 Door handle 19 Frozen product storage tank 191 Heat-conductive inner wall of frozen product storage tank 192 Heat-insulating side plate 193 Heat-insulating bottom plate 194 Slide-type cover 195 Frozen product storage antifreeze 20 Thawing treatment chamber door 201 Door handle 21 Thawing treatment tank 211 Heat-conductive inner wall of thawing treatment tank 212 Heat-insulating side plate 213 Heat-insulating bottom plate 214 Slide-type cover 215 Thawing treatment antifreeze 22 Fan 23 Stirrer 24 Temperature sensor 25 Timer 26 Refrigeration, thawing, and refrigerator temperature control unit 27 Processing and storage basket 28 Vacuum packaging machine 29 Raw steak before freezing, vacuum-packed with polyethylene

Claims

1. A refrigerator with a function of freezing food, a function of storing frozen food, and a function of thawing frozen food, a pre-freezing treatment chamber where the pre-freezing treatment of the food is performed and is controlled to a pre-freezing treatment temperature of about 2 to 5 °C, a freezing chamber where the food treated in the pre-freezing treatment chamber is frozen and is controlled to a freezing temperature of about -40 to -20 °C, a storage chamber where the frozen food frozen in the freezing chamber is stored and is controlled to a storage temperature of about -40 to -18 °C, a thawing chamber where the thawing of the frozen food is performed and is controlled to a thawing temperature of about -5 to 0 °C, characterized by comprising the above.

2. The refrigerator according to claim 1, characterized in that the refrigerant controlled to the freezing temperature and the refrigerant controlled to the thawing temperature are liquids.

3. The refrigerator according to claim 2, characterized in that the refrigerant controlled to the pre-freezing treatment temperature is a liquid.

4. The refrigerator according to claim 2, characterized in that the refrigerant controlled to the storage temperature is a liquid.

5. The refrigerator according to claim 4, characterized in that the refrigerant controlled to the pre-freezing treatment temperature is a liquid.

6. The refrigerator according to any one of claims 1 to 5, characterized in that the food is provided with a refrigerating chamber controlled to a refrigerating temperature of about 3 to 6 °C.

7. In the refrigerator according to any one of claims 1 to 5, a freezing preparation step of cutting the food to a thickness of about 10.0 cm or less and packaging it with a sealable plastic film, a pre-freezing treatment step in the pre-freezing treatment chamber, where the frozen food packaged in the freezing preparation step is subjected to a low-temperature treatment for a predetermined time, a freezing step in the freezing chamber, where the frozen food that has undergone the pre-freezing treatment step is subjected to a freezing treatment for a predetermined time, a storage step in the storage chamber, where the frozen food frozen in the freezing step is stored for a predetermined period, a thawing step in the thawing chamber, where the frozen food that has undergone the storage step is subjected to a thawing treatment in a predetermined time, characterized by including the above.

8. In the refrigerator according to claim 6, a freezing preparation step of cutting the food to a thickness of about 10.0 cm or less and packaging it with a sealable plastic film, a pre-freezing treatment step in the pre-freezing treatment chamber, where the frozen food packaged in the freezing preparation step is subjected to a low-temperature treatment for a predetermined time, In the freezer compartment, a freezing step in which the frozen food that has undergone the pre-freezing treatment step is subjected to a freezing treatment for a predetermined time, and In the storage compartment, a storage step in which the frozen food frozen in the freezing step is stored for a predetermined period, and In the thawing compartment, a thawing step in which the frozen food that has undergone the storage step is subjected to a thawing treatment for a predetermined time, and A method of using a freezer-refrigerator, characterized by including the above steps.

9. The method of using a freezer-refrigerator according to claim 7, wherein the packaging performed in the freezing preparation step is vacuum packaging.

10. The method of using a freezer-refrigerator according to claim 8, wherein the packaging performed in the freezing preparation step is vacuum packaging.

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