JP2007278647A - Cooling storage cabinet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a cell membrane from being broken as much as possible as ice crystals of moisture in a cooled object become larger when storing the cooled object such as food at low temperatures (equal to or lower than freezing temperature). <P>SOLUTION: In a freezing method of the cooling storage cabinet 1 equipped with a refrigerating device 5 and a freezing chamber 3 for cooling the cooled object 10 by cold air from the refrigerating device 5, the cooled object 10 is applied with ultrasonic vibration by an ultrasonic vibrator 11. As thermal energy applied for the cooled object 10 by the ultrasonic vibrator 11 is smaller than thermal energy taken from the cooled object 10 by the cold air, the cooled object 10 is frozen. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling storage such as a refrigerator-freezer that freezes and stores an object to be cooled such as meat in a freezer compartment.

  It is well known that when a food is frozen, the smaller the ice crystals formed in the food, the less damage the food has.

  When freezing food, it is important to pass through the maximum ice crystal formation zone quickly and rapid cooling is used.

  Even if rapid cooling is performed, if the food is thick, freezing at the center of the food is delayed. For this reason, as shown in Patent Document 1, it is known to pre-cool food in order to reduce the temperature difference between the outside and the center of the food.

In addition to simple rapid cooling, as a method of reducing the ice crystals generated in foods, during cooling, external forces such as electric fields, magnetic fields, and ultrasonic waves are applied to the food to keep it in a supercooled state that does not freeze the food, After that, some foods are frozen by stopping the external force (see Non-Patent Document 1 and Patent Document 2). In addition, about this method, it is theoretically precedent at present, and it seems that scientific basis and the quality of the frozen food are not proved (refer nonpatent literature 2).
Japanese Patent Laid-Open No. 6-101949 JP 2004-44891 A Journal “Invention” published by the Society of Inventions November 2005 “Special Feature Hot Frontiers of Frozen Foods” 17p-19p. Magazine "Frozen" published by the Japan Society of Refrigerating and Air Conditioning, December 2005 issue Toru Suzuki "Searching for New Technology from Basic Principles" 4p-8p.

  The present invention provides a cold storage with little damage to foods when frozen and a method for freezing the same.

  The cooling storage (1) of the present invention includes an ultrasonic vibrator (11) that applies ultrasonic vibration to an object (10) to be cooled in the freezer compartment (3).

  Moreover, this invention is a freezing method of a cooling store | warehouse | chamber (1) provided with the cooler (5) and the freezing room (3) which cools and freezes to-be-cooled object (10) with the cold air from this cooler (5). The ultrasonic vibration is applied to the object to be cooled (10) by the ultrasonic vibrator (11), and the thermal energy given to the object to be cooled (10) by the ultrasonic vibrator (11) is caused by the cold air. The object to be cooled (10) is frozen by making it smaller than the thermal energy taken away from the object (10) to be cooled.

  According to the present invention, the amount of drip generated when thawing frozen meat is reduced.

  When the object to be cooled such as food is frozen and stored, the object to be cooled is frozen while applying the ultrasonic vibration from the ultrasonic vibrator to the object to be cooled.

  Example 1 which is the refrigerator-freezer (cooling storage) which implemented this invention is demonstrated using FIGS. 1-4. 1 is a cross-sectional view of the lower part of the refrigerator-freezer of Example 1. FIG. FIG. 2 is a block circuit diagram of the control system. FIG. 3 is a flowchart for cooling the food. FIG. 4 is a temperature change diagram when the food (cooled object) is cooled.

  In FIG. 1, 2 is a freezing temperature zone room (freezing room) of the refrigerator 1. 3 is also a freezer compartment. Reference numeral 4 is a compressor, and 5 is a cooler for cooling the freezing compartments 3 and 4. In addition, the refrigeration temperature zone room (refrigeration room / vegetable room) (not shown) is cooled by a second cooler (not shown).

  Reference numeral 6 denotes a blower for circulating cold air, which supplies the cold air from the cooler 5 to both freezing rooms 2 and 3. Reference numeral 7 denotes a damper. The damper 7 is controlled to be opened and closed to adjust the cold air supplied to the freezer compartment 3. 8 is a container in the freezer compartment. An infrared temperature sensor 9 detects the surface temperature of the food 10 in the freezer compartment 3. Reference numeral 11 denotes an ultrasonic vibrator, which is attached to the back surface of the container 8.

  In FIG. 2, 12 is a control circuit comprising a one-chip microcomputer or the like. An operation panel 13 is provided on the front surface of the refrigerator compartment door of the refrigerator 1. Reference numeral 14 denotes a freezer compartment temperature sensor for measuring the temperature in the freezer compartment 2.

  The cooling of the refrigerator-freezer 1 will be described. In addition, this description is related to the freezer compartment 2, and a description of the refrigerated temperature zone chamber is omitted.

  When the control circuit 12 detects an increase in the temperature of the freezer compartment 2 based on the output from the freezer temperature sensor 14 in FIG. 2, the control circuit 12 turns on the compressor 4 and the blower 6 and fully opens the damper 7. The cooler 5 is cooled by the operation of the compressor 4, and the air cooled by the cooler 5 is circulated to the freezer compartments 2 and 3 by the blower 6 as indicated by arrows in FIG. 1. Thereby, the freezer compartments 2 and 3 are cooled. This refrigerator-freezer 1 is designed in advance so that the freezer compartment 3 is cooled preferentially when the damper 7 is fully opened. When the control circuit 12 detects that the temperature of the freezer compartment 3 has decreased to a predetermined temperature by the output from the infrared sensor 9, the control circuit 12 fully closes the damper 7. The cool air from the cooler 5 is supplied only to the freezer compartment 2. When the control circuit 12 detects a temperature drop to the predetermined temperature in the freezer compartment 2 based on the output from the freezer temperature sensor 14, the control circuit 12 turns off the compressor 4 and the blower 6.

  Next, freezing using ultrasonic waves will be described. A user puts food in the container 8 of the freezer compartment 3 and closes the freezer compartment door. The user presses the “ultrasonic freezing” button in the operation panel 13 (S1 in FIG. 3).

  As a result, the control circuit 12 turns on the compressor 4 and the blower 6, fully opens the damper 7, and turns on the ultrasonic transducer 11 (S <b> 2 in FIG. 3). The cooler 5 is cooled by the operation of the compressor 4, and the air cooled by the cooler 5 is circulated to the freezer compartments 2 and 3 by the blower 6. Thereby, the freezer compartment 3 is mainly cooled.

Thereby, as shown in FIG. 4, the surface temperature of food falls. The control circuit 12 monitors the surface temperature of the food 10 based on the output from the infrared temperature sensor 9.

  Here, when the surface temperature reaches 1 ° C., the damper 7 is closed to stop the cooling of the food 10. When the surface temperature rises to 2.5 ° C., the damper 7 is opened and the cooling of the food 10 is restarted (S3 in FIG. 3). Thereby, as FIG. 4 shows, the surface temperature of a foodstuff is controlled to fixed temperature (1 degreeC-2.5 degreeC). In this way, the food was pre-cooled and waited until it was cooled to the center of the food, which was 30 minutes in Example 1 (S4 in FIG. 3). The constant temperature is ideally the lowest temperature at which the food does not freeze.

  For example, water has a freezing point temperature of 0 ° C., but when water is cooled, it actually does not freeze even when the temperature falls below 0 ° C. (supercooled state), and when it is further cooled, the supercooled state breaks and begins to freeze. That is well known. Therefore, it was considered once that a temperature lower than minus 1 ° C. to minus 4 ° C. is optimal for general foods (minus 1 ° C. to minus 4 ° C.) having a freezing point temperature lower than that of water.

  However, in the supercooled state, the temperature at which the supercooled state is broken is not a constant temperature. That is, the occurrence of a phenomenon in which freezing occurs (supercooling is broken) occurs stochastically. Therefore, there is a possibility that it will always start freezing below the freezing point temperature.

  Therefore, the inventor of the present application selects 0 ° C. as the ideal value of the above-mentioned constant temperature, and in actual control, taking into account measurement error and cold air non-uniformity, between 1 ° C. and 2.5 ° C. Selected.

  Thereby, it can be set as the minimum temperature in the range which a foodstuff does not freeze and is controllable with a refrigerator-freezer.

  When this fixed temperature period exceeds 30 minutes, the control circuit 12 opens the damper 7 to cool the food 10 (S4, S5 in FIG. 3). As shown in FIG. 4, the surface temperature of the food is lowered and becomes supercooled. Furthermore, if the cooling is continued, the supercooled state is broken, and the food surface temperature rises rapidly to near the freezing point temperature. At this time, ice crystals are growing in the food. After that, it is detected by the infrared sensor that the food is cooled to minus 18 ° C. (S6 in FIG. 3), and then the ultrasonic transducer 11 is turned off (S7, S8 in FIG. 3) 30 minutes later to switch to this mode. The process ends (S9 in FIG. 3).

  According to the present invention, the amount of drip generated when meat is frozen and thawed is reduced.

  In the first embodiment, the damper 7 is controlled at a constant temperature by repeating two states of fully closed and fully opened. However, this may be performed by adjusting the opening degree of the damper 7.

  In the first embodiment, the damper 7 performs the constant temperature control by repeating the two states of the fully closed state and the fully opened state, but this may be performed by adjusting the rotational speed of the blower 6.

  Further, the constant temperature control may be performed by applying thermal energy equivalent to cooling energy by cold air by an electric field, a magnetic field, ultrasonic waves, or the like.

  Moreover, in Example 1, constant temperature control is performed to reduce the temperature difference between the surface temperature of the food and the center temperature, and then normal strength cooling is performed again, so that the central portion is quickly frozen, so constant temperature control is performed. However, the present application is not limited to this.

  In the first embodiment, the ultrasonic transducer 11 is turned on immediately after the button operation on the operation panel 13, but this is considered sufficient if performed at the time of freezing (when an ice crystal is generated and grown). As shown in FIG. 5, it may be turned on at the end of the constant temperature control and turned off at the end of freezing (at the end of passing through the maximum ice crystal growth temperature zone).

  Note that detection at the end of freezing in a true sense is difficult in an actual refrigerator because the temperature of the center of the food must be measured. Therefore, in Examples 1 and 2, the time when 30 minutes had elapsed after the surface temperature of the food became minus 18 ° C. was regarded as the end of freezing. However, the present application is not limited to this.

  According to the present invention, it is considered that ice crystals when food is frozen can be uniformly reduced. Therefore, it can be applied to frozen storage of food.

It is sectional drawing of the lower part of the refrigerator-freezer of Example 1 of this invention. It is a reference diagram for demonstrating the control system of the refrigerator-freezer of Example 1. FIG. FIG. 3 is a flowchart for explaining control of the first embodiment. It is a figure for demonstrating the temperature change of the foodstuff in Example 1. FIG. It is a figure for demonstrating the temperature change of the foodstuff in Example 2. FIG.

Explanation of symbols

2 refrigerator-freezer (cooling storage),
3 Freezer room,
5 cooler,
6 Cooler blower,
7 Damper,
9 Infrared temperature sensor,
1 Food (object to be cooled).

Claims (2)

A cooling storage comprising an ultrasonic vibrator for applying ultrasonic vibration to an object to be cooled in a freezer compartment. In a refrigeration method for a cold storage comprising a cooler and a freezing room for cooling and freezing an object to be cooled by cold air from the cooler,
The object to be cooled is subjected to ultrasonic vibration by an ultrasonic vibrator, and the thermal energy given to the object to be cooled by the ultrasonic vibrator is made smaller than the heat energy taken away from the object to be cooled by the cold air. A freezing method characterized by freezing a cooling object.

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