JP7350317B2 - Continuous freezing equipment and continuous freezing method - Google Patents

Description

The present invention relates to a continuous freezing device and a continuous freezing method for continuously freezing objects to be frozen, such as fresh foods such as vegetables, raw meat, seafood, and fruits, so that drips do not occur during thawing.

BACKGROUND ART Conventionally, fresh foods such as vegetables, raw meat, seafood, and fruits have been frozen and preserved in order to maintain their freshness. Frozen preservation is performed by rapidly freezing the object to be frozen from room temperature to -35°C to -45°C in the freezing section. However, this method has a problem in that drips occur when the frozen object is thawed, resulting in the frozen object becoming watery. The occurrence of drips is caused by ice crystals inside cells expanding during freezing and destroying cell membranes. If the cell membrane is destroyed in this way, during thawing, water inside the cells flows out through the destroyed cell membrane, resulting in dripping.

Therefore, attempts have been made to prevent the occurrence of this drip. For example, in Patent Document 1, a plurality of negative static electron generation transformers equipped with high output resistances are used to induce high voltage negative static electrons in a refrigerator, and a negative static electron band is generated at a voltage between 1V and 4999V. The food is first cooled in a non-freezing state in the freezing temperature range of 0°C to -3°C, the solid temperature range of the food is stabilized in a non-freezing state, and then the temperature range of -30°C to - It is described that secondary freezing is performed by transferring to a freezing section at 45°C.

Furthermore, Patent Document 2 discloses that an alternating electric field is applied to an object to be frozen housed in the internal space of a freezer to rapidly freeze it to a predetermined temperature of -20°C to -30°C while suppressing freezing of moisture. After that, the action of the alternating electric field is stopped, and a refrigeration device is described which instantaneously freezes at this predetermined temperature. Furthermore, Patent Document 3 describes the production of highly fresh frozen raw vegetables that is similarly rapidly frozen to -20°C to -50°C under the action of a static magnetic field and a fluctuating magnetic field instead of or in addition to an alternating electric field. The method is described.

Japanese Patent Application Publication No. 9-61044 Japanese Patent Application Publication No. 2003-88347 Japanese Patent Application Publication No. 2004-81133

In the method described in Patent Document 1, the object to be frozen is stored in a closed refrigerator, and after primary cooling is performed in this refrigerator, it is transferred to a similarly closed freezing section and subjected to secondary freezing. It is. Therefore, when processing a large amount of frozen objects, it is necessary for workers to manually take them in and out, or transfer them from the refrigerator to the freezing section, which requires continuous processing of large amounts of frozen objects. cannot be processed.

Furthermore, Patent Document 1 states that it is not necessarily necessary to transfer from the primary cooling chamber to the secondary cooling chamber, and after confirming the completion of primary cooling, the power to the negative static electron generating transformer is shut off and the secondary cooling is directly performed. Although it is stated that the temperature may be shifted, even in this case, the temperature inside the refrigerator must be lowered from the primary cooling temperature to the secondary cooling temperature or raised from the secondary cooling temperature to the primary cooling temperature each time freezing is performed. Because of the necessity, it is not possible to process large quantities of frozen objects continuously.

In the methods described in Patent Documents 2 and 3, the objects to be frozen are stored and frozen in a closed refrigerator, so similarly to the method described in Patent Document 1, a large amount of objects to be frozen are frozen. In this case, it is necessary for the worker to manually take in and out the frozen objects each time, and it is not possible to process a large amount of frozen objects continuously.

Therefore, the present invention provides a continuous freezing device and a continuous freezing method that are capable of continuously freezing a large amount of frozen objects while conveying them and reducing the amount of drips during thawing. The purpose is to

The continuous freezing device of the present invention is a conveyor belt that conveys an object to be frozen, and is made of a conductor and is grounded, and cool air is blown toward the object to be frozen on the conveyor belt to freeze the object. a cooling unit for cooling, and a mesh electrode disposed parallel to the conveyor belt at a predetermined distance between the conveyor belt and the cooling unit and in a range where the frozen object reaches the maximum ice crystal formation temperature range on the conveyor belt. It has a mesh electrode to which a high voltage is applied.

The continuous freezing method of the present invention involves blowing cold air from a cooling unit toward the frozen object on the conveyor belt while conveying the frozen object on a grounded conveyor belt made of a conductor to freeze the frozen object. A continuous freezing method in which the frozen object is placed parallel to the conveyor belt at a predetermined distance between the conveyor belt and the cooling unit in the range where the maximum ice crystal formation temperature range occurs on the conveyor belt. The method includes applying a high voltage to the mesh electrode.

According to these inventions, the object to be frozen is continuously frozen by being blown with cold air from the cooling unit while being conveyed on the conveyor belt. (temperature range from the start of freezing to freezing), high voltage is applied from the mesh electrode and cold air is blown through the gaps between the meshes of the mesh electrode, resulting in rapid cooling. At this time, a high voltage is applied to the frozen object from the mesh electrode, which activates its constituent molecules and supercools the object without freezing even in the maximum ice crystal formation temperature range. By going from a cooling state to freezing all at once, the water inside the cells does not become enlarged and maintains the state of fine ice crystals, so the object to be frozen is frozen without destroying the cell membrane. .

According to the present invention, it is possible to rapidly freeze a large amount of frozen objects such as vegetables, raw meat, seafood, fruits, and other fresh foods while transporting them without destroying their cell membranes. It becomes possible to reduce the amount of drip.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the continuous freezing apparatus in embodiment of this invention. FIG. 2 is a perspective view of the conveyor portion of FIG. 1; FIG. 7 is a perspective view showing another form of supporting the mesh electrode. FIG. 3 is a diagram showing an example of a waveform of a DC pulse voltage applied to a mesh electrode. It is a figure which shows the example of the waveform of the alternating current voltage applied to a mesh electrode.

FIG. 1 is a schematic configuration diagram of a continuous freezing device according to an embodiment of the present invention, and FIG. 2 is a perspective view of the conveyor portion of FIG. 1.

In FIG. 1, the continuous freezing apparatus according to the embodiment of the present invention includes a refrigerator 2 that freezes an object 1 to be frozen, a conveyor 3 that conveys the object 1 to be frozen and passes through the refrigerator 2, and a refrigerator 2. 2, a refrigeration device 5 that cools the air and supplies it to the cooling unit 4, a high-voltage discharger 6 supported by the cooling unit 4, and a high-voltage discharger 6 It has a high voltage generator 7 that generates a high voltage to be applied.

The conveyor 3 includes a pair of rollers 30A, 30B, a conveyor belt 31 as an endless annular body wrapped around the pair of rollers 30A, 30B, and a rail that supports the conveyor belt 31 between the pair of rollers 30A, 30B. 32, shafts 33A and 33B that respectively support a pair of rollers 30A and 30B, a drive motor 34 that drives the conveyor 3, and a drive chain 35 that transmits the driving force of the drive motor 34 to the shaft 33A. .

The pair of rollers 30A, 30B, the conveyor belt 31, the rail 32, and the shafts 33A, 33B are made of a conductor such as stainless steel or conductive resin. Shaft 33A is a driving shaft, and shaft 33B is a driven shaft. Shaft 33A is grounded. The driving force of the drive motor 34 is transmitted to the shaft 33A, and by rotating the roller 30A, the conveyor belt 31 is operated and the frozen object 1 on the conveyor belt 31 is conveyed in the conveyance direction X1. The roller 30B is rotated by the conveyor belt 31.

A pair of rollers 30A and 30B are arranged outside the refrigerator 2, respectively. That is, the conveyor 3 is provided so as to penetrate from the entrance side opening 2A to the exit side opening 2B of the refrigerator 2. The object to be frozen 1 is conveyed from the outside of the refrigerator 2 by the conveyor 3, and is carried into the refrigerator 2 through the entrance side opening 2A. The object to be frozen 1 carried into the refrigerator 2 is transported inside the refrigerator 2, and is taken out of the refrigerator 2 from the outlet side opening 2B.

The cooling unit 4 includes a fan 4A that blows air (cold air) cooled to −20° C. to −55° C. by the freezing device 5 toward the frozen object 1 on the conveyor belt 31 of the conveyor 3. The object to be frozen 1 is cooled by cold air blown by the cooling unit 4 while being conveyed on the conveyor belt 31, and is finally frozen to -18° C. to -50° C., and is carried out from the exit side opening 2B.

As shown in FIG. 2, the high voltage discharger 6 has a mesh electrode 60 formed of a conductor in a mesh shape. The mesh electrode 60 is disposed between the conveyor belt 31 and the cooling unit 4 in parallel with the conveyor belt 31 at a predetermined distance. The mesh electrode 60 is supported by the cooling unit 4 via an insulator 61. Note that the mesh electrode 60 is disposed on the conveyor belt 31 in a range where the frozen object 1 is in the maximum ice crystal formation temperature range. The maximum ice crystal formation temperature range is the temperature range in which ice crystals tend to grow during the process of freezing the frozen object 1, and is the temperature range from the beginning of freezing (about -1°C) to freezing (about -5°C). refers to

The mesh electrode 60 is connected to the high voltage generator 7 by a high voltage cable 62. The high voltage generator 7 is a device that generates a high voltage, for example, a DC pulse voltage of 800V to 10000V, more preferably 3000V to 7000V, and even more preferably 4000V to 5000V. The DC pulse voltage is one in which high voltage application and non-application are repeated intermittently at intervals of 0.001 seconds to 0.2 seconds. FIG. 4 shows an example of the waveform of the DC pulse voltage applied to the mesh electrode 60. The voltage value and the pulse interval can be changed depending on the frozen object 1.

In the continuous freezing device configured as described above, the object to be frozen at room temperature 1 is placed on the conveyor belt 31 of the conveyor 3, carried into the cooling chamber 2 through the entrance side opening 2A, and air (chilled air) cooled by the freezing device 5 is transported. ) is blown by the fan 4A of the cooling unit 4 to freeze it, and then carried out from the outlet side opening 2B. At this time, the temperature inside the refrigerator 2 is -30°C to -50°C, and the object to be frozen 1 is frozen from room temperature to about -18°C to -40°C, but the object to be frozen 1 is -1°C. In the temperature range where the maximum ice crystal formation occurs, from about -5° C., a high voltage DC pulse voltage is applied from the high voltage discharger 6 (mesh electrode 60).

As a result, the constituent molecules of the object 1 to be frozen are activated, and the object 1 is supercooled without freezing even in the maximum ice crystal formation temperature range. After that, when the mesh electrode 60 is out of the installation range, it is suddenly frozen from this supercooled state, so that the water inside the cells does not become enlarged and maintains the state of fine ice crystals. Since the frozen object 1 is frozen without destroying its cell membrane, the amount of drips during thawing is reduced.

In addition, in this continuous freezing device, even in the installation range of the high voltage discharger 6, the cold air blown by the fan 4A of the cooling unit 4 is blown onto the frozen object 1 through the gaps between the meshes of the mesh electrode 60, so that the object 1 can be frozen. The time is shortened, and the object 1 to be frozen can be frozen quickly. In addition, in this continuous freezing device, by changing the length of the insulator 61 according to the size of the frozen object 1, the discharge distance from the mesh electrode 60 to the frozen object 1 can be kept constant. It is possible to efficiently freeze the frozen object 1.

In the illustrated example, the shaft 33A is grounded, but any one of the pair of rollers 30A, 30B, the conveyor belt 31, the rail 32, and the shafts 33A, 33B may be grounded. Although not shown, the ground electrode of the high voltage generator 7 is also grounded.

Further, the high voltage generator 7 may be a device that generates an AC voltage (frequency: 50 Hz to 500 Hz) of, for example, 800 to 10,000 V, more preferably 3,000 to 7,000 V, and still more preferably around 3,500 V. FIG. 5 shows an example of the waveform of the AC voltage applied to the mesh electrode 60. The voltage value and frequency can be changed depending on the object 1 to be frozen.

Further, as shown in FIG. 3, the high voltage discharger 6 (mesh electrode 60) may be supported by an insulator 63 from the bottom side of the refrigerator 2.

The continuous freezing apparatus and the continuous freezing method of the present invention are apparatuses and apparatuses that continuously freeze objects to be frozen such as fresh foods such as vegetables, raw meat, seafood, and fruits so that the amount of drips during thawing is reduced. It is useful as a method.

1 Frozen object 2 Refrigerator 3 Conveyor 30A, 30B Roller 31 Conveyor belt 32 Rail 33A, 33B Shaft 34 Drive motor 35 Drive chain 4 Cooling unit 4A Fan 5 Freezer 6 High voltage discharger 60 Net electrode 61, 63 Insulator 62 High voltage cable 7 High voltage generator

Claims (5)

It is a conveyor belt that conveys frozen objects, and is made of a conductor and is grounded.
a cooling unit that blows cold air toward the frozen object on the conveyor belt to freeze the frozen object;
A mesh electrode disposed in parallel with the conveyor belt at a predetermined distance between the conveyor belt and the cooling unit and in a range where the frozen object on the conveyor belt has a maximum ice crystal formation temperature range. A continuous freezing device with a mesh electrode to which a high voltage of 800 to 10,000V is applied. The continuous freezing apparatus according to claim 1, wherein the high voltage is a DC pulse voltage of 800 to 10,000V. The continuous freezing apparatus according to claim 2, wherein the DC pulse voltage is applied at intervals of 0.001 seconds to 0.2 seconds. The continuous freezing apparatus according to claim 1, wherein the high voltage is an AC voltage of 800 to 10,000V. A continuous freezing method in which the object to be frozen is conveyed on a grounded conveyor belt made of a conductor, and cool air is blown from a cooling unit toward the object on the conveyor belt to freeze the object. ,
A mesh electrode is provided between the conveyor belt and the cooling unit, and is arranged parallel to the conveyor belt at a predetermined distance in a range where the object to be frozen on the conveyor belt has a maximum ice crystal formation temperature range. A continuous freezing method that involves applying a high voltage of 800 to 10,000V .

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