JPS6312271A - Method for thawing and refrigerating frozen food - Google Patents

Abstract

PURPOSE:To thaw and refrigerate a food without impairing the freshness and quality thereof, by starting thawing of the frozen food while maintaining the interior of a thawing refrigerator at a specific temperature and slowly thawing the food while maintaining the interior at a temperature lower than the temperature when the core temperature of the food attains the temperature zone of the maximum ice crystal formation. CONSTITUTION:In thawing a frozen food by blowing heated and humidified air on the food, the temperature in a thawing refrigerator is at first set at a relatively high temperature (T1). The setting of the temperature in the refrigerator is next changed to a temperature (T2) lower than the original temperature (T1) when the temperature of the core part of the food attains the temperature zone (TC) of the maximum ice crystal formation to slowly thaw the food. When the thawing is completed, the temperature in the refrigerator is set at the optimum refrigeration temperature (T3).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for thawing frozen fish, fish roe, livestock meat, etc. that has been Q-speed frozen at low or ultra-low temperatures without impairing the freshness and quality of the frozen products. This relates to a method for thawing fish and frozen fish roe in a short time and economically while suppressing the loss of weight that occurs during thawing, especially when temporarily thawing frozen fish and frozen fish roe to be used as raw materials for seafood processing, and when
This relates to a thawing and refrigeration method that is most effective when the fish is directly consumed.

Conventional technology Conventionally, for example, when thawing frozen fish in large quantities on an industrial scale,
Natural thawing method, water thawing method, warm air thawing method, etc. are traditionally and commonly used, but these methods all significantly reduce the freshness in the bran and after thawing, resulting in loss of freshness in the meat tissue. There are many problems in terms of quality control because cell fluid and blood flow out as drips.

For example, natural thawing methods are directly affected by changes in season and temperature, as seen in dirt floor thawing and solar thawing, and the thawing products are exposed to sunlight and the outside air for long periods of time, resulting in oxidation of the meat tissue and loss of the epidermis. If the freshness is significantly reduced and the temperature rises, bacteria will grow not only in the fish but also in the body fluids and blood dripping into the factory, causing spoilage and causing food hygiene management issues such as a rotten smell filling the processing factory. But there are many problems.

In addition, when freezing with water, the frozen product is immersed directly in fresh water or water, or the frozen product is forcibly thawed by sprinkling 7H of water on it, but this method takes less time than the natural thawing method. However, since the surface of the fish melts while the inside is frozen, the thawed meat tissue swells with water, destroying the cells and causing drips to flow out, which not only impairs the quality of the fish body, but also reduces the nutrients in the fish meat. There was a rift that made the food lose its flavor. This phenomenon occurs because the thermal conductivity of water is low, so water acts as a kind of heat insulating film between the melted and frozen parts of the surface, making it difficult for heat received from the outside to be transferred to the inside. As a result, the waterlogged state gradually increases, degrading the quality and contaminating the large amount of water used for thawing, which becomes a new source of pollution. In addition, unhygienic conditions during food processing result in customers and consumers avoiding the product, creating a more disadvantageous situation in terms of product quality.

In addition, in cold regions, water work in winter is impossible, so
Various efforts have been made, such as using drought water for thawing and injecting steam into the thawing water to replenish heat, but sometimes the thawing water freezes due to the cold heat of frozen products, damaging fish bodies and fish eggs. This is causing new economic losses such as freezing C accidents such as frozen children.

The air thawing method using hot air is a method of thawing air heated by a heater and sent to the thawing chamber using a fan.Similar to hot water thawing,
Popular in cold regions. However, with this method, it is difficult to maintain stable temperature and humidity inside the refrigerator, and the air circulation inside the refrigerator is not uniform, resulting in uneven thawing and unevenness in the thawed products. This impedes the uniformity of quality at the stage of commercialization. In particular, this thawing method is not considered appropriate in terms of quality control in seafood processing factories that temporarily thaw and process large quantities of fish.

In consideration of the above-mentioned problems, an air thawing method has recently been developed in which low-temperature, humid air is supplied to the thawing chamber to defrost the product. It has been developed with emphasis on refrigeration as a general-purpose type for home use, so it can shorten thawing time, control the amount of thawing heat, and thaw differently depending on the species of fish, which is an important function for intensively thawing large quantities of frozen fish on an industrial scale. It is insufficient in terms of terminating thawing based on the final temperature and preventing quality deterioration due to excessive thawing, and the level of progress in related industries is still low.

As mentioned above, conventional methods for thawing frozen fish have been exemplified in each category, but all methods for thawing frozen fish on an industrial scale have advantages and disadvantages in terms of quality control, workability, and cost, and there are still 11 definitive thawing methods. It has not been done.

The present invention has been made in view of the above problems, and its purpose is to provide a method for efficiently thawing and refrigerating frozen products frozen at low or ultra-low temperatures without impairing quality. .

Means for Solving the Problems In order to achieve the above object, the present invention first sets the air temperature in the freezer/refrigerator In to a first temperature when blowing heated (heated) and humidified air onto a frozen product to thaw it. At the same time, the core temperature of the product to be thawed is detected, and when the core temperature reaches the maximum ice crystal formation temperature range of the tissue of the product to be thawed, the humidity in the refrigerator is The gist is that the second temperature is re-controlled and maintained at a second temperature lower than the first temperature, thawing is performed slowly, and the thawing is completed when the core temperature reaches a predetermined thawing line temperature. It is.

In addition, the invention of Application No. 2 stops heating the air blown into the freezer/refrigerator after thawing as described above, detects the air temperature inside the refrigerator, and controls the temperature to a predetermined refrigeration temperature. The main idea is to refrigerate frozen products using low-temperature, high-humidity air.

Furthermore, in the invention of the second aspect of the present application, heating of the air is stopped and blowing of air into the refrigerator is also stopped, and the temperature of the air inside the refrigerator is detected and the temperature in the refrigerator is adjusted to a predetermined ice temperature II1.
．． It can be controlled and maintained by the audience, and thawed products can be refrigerated at freezing temperatures.

Taking frozen fish as an example of a frozen product, when thawing frozen fish frozen at low or ultra-low temperatures, the first humidity level is high humidity in the temperature range of about 20°C to 30°C at the early stage of thawing when the freezing temperature is low. of air is supplied into the thawing chamber 1111, and this air is blown at a speed of 3 m (meters) per second by a thawing fan inside the chamber.
When the product is accelerated and sprayed within a range of 6 meters from
For the surface temperature and core temperature of frozen fish, follow the thawing curve shown in 1st m.
6 and the temperature rises rapidly. This is because the latent heat of water vapor released when hot water droplets of water vapor and fine particles contained in heated and humidified air come into contact with a frozen product and freeze into a mist, and the actual heat of the hot water and air are released into the interior. This is due to the result of heat transfer, and is also due to the effect that inside the frozen product, the transferred external heat is transferred to the center of the core by ice, which has a much higher thermal conductivity than water. Heat exchange is performed efficiently, the temperature difference between the two is reduced, and thawing proceeds while the surface of the product to be thawed remains frozen. the result,
No tissue destruction occurred in the surface layer, and no drips were observed. In this way, when the heated and humidified air is continuously supplied into the refrigerator at a predetermined flow rate, the quality of the product to be thawed is not impaired and thawing is completed in a short time.

Next, when the stomach temperature of the product to be thawed reaches 15° C., the maximum ice crystal formation temperature range is reached, but thawing in this temperature range must be performed slowly. If thawing is continued for a short period of time, the water that has melted within the tissue will not be absorbed into the tissue and will grow into clumps, destroying cells and causing drip leaching. Once this drip starts flowing out, it is difficult to stop, and the quality of fish meat or fish roe is significantly impaired.

In the thawing method according to the present invention, in order to pass through this maximum ice crystal formation temperature range at a slow speed, a temperature detection element is attached to the core of the frozen product, and the temperature inside the refrigerator is adjusted by detecting the ice crystal formation temperature. The temperature is controlled to a low temperature range of 3°C to 5°C, which is the temperature in step 2, and maintained. In this way, the amount of spillage during thawing is drastically reduced compared to the conventional thawing method. This method is particularly effective for thawing frozen fish eggs, such as herring roe, and does not cause destruction of the egg nucleus or outflow of cell fluid, which is normally seen during thawing, so the quality can be improved during pre-processing of the roe after thawing. The occurrence of deterioration and eye loss is greatly improved compared to conventional methods.

Furthermore, the freezing point of frozen fish varies somewhat depending on the species of fish, but on average it is in the temperature range of -2°C to -11°C, so thawing can be completed when the body temperature of the fish reaches the freezing temperature. The temperature range between this thawing line temperature and 0°C is the so-called freezing temperature range, and although there is no freezing, no bacterial activity is observed and fish meat is ripened. Therefore, if thawing is completed at this thawing line temperature, the best quality can be obtained. The thawing method according to the present invention focuses on this effect, detects the center temperature of frozen fish with a temperature detection element, and when the temperature reaches a predetermined final thawing temperature, stops heating the air in the refrigerator to finish thawing. Zuru.

Next, after thawing the Moejo, if continued refrigeration is required for factory work preparations, etc., the temperature inside the refrigerator should be kept in the low range of 3℃ to 5℃, and the humidity inside the chamber should be kept at 90℃ to prevent drying. If the relative humidity is maintained at around 100% and the cleanliness is maintained at about NAS△10.000 class, new contamination by external bacteria will not occur, and at the same time, strange odors inside the refrigerator will be removed and odor transfer between foods will be prevented. This allows you to maintain the best sanitary conditions inside the refrigerator. The refrigeration method after thawing according to the present invention focuses on the above points, and circulates and supplies low temperature, high humidity, and highly clean air into the refrigerator after thawing is completed. As a result, it is possible to maintain the freshness of meat for a long period of time and to prevent the loss of meat due to the leakage of drips, which has not been seen before, and at the same time, it is possible to remove odors in the refrigerator and to significantly improve the sanitary conditions. In addition, in this refrigeration method, if the supply of humidified air into the refrigerator is stopped and the air inside the refrigerator is cooled and maintained at the freezing temperature range of the refrigerated items mentioned above, not only the growth of bacteria but also the ripening of the food will be inhibited. , it is possible to maintain the freshness at its best.

Example An embodiment of the present invention will be described below based on the drawings.

Fig. 2 shows an example of a defrosting device for realizing the present Komei method. 1 is a defrosting/refrigerator whose surroundings are insulated, and a refrigerator 2 is mounted on the ceiling and a plurality of defrosting fans 3 are installed inside. It is installed. Thaw/Frozen fish to be thawed in refrigerator 1 4
When the refrigerator is brought in and the thawing operation starts, the air inside the refrigerator is sent to the air cleaner 1-56 installed outside the refrigerator through the duct 5 to the turbo
It is sucked by the blower 7. The turbo blower 7
rotates at a high speed at a predetermined speed, but this rotational speed (2) can be varied by the drive inverter motor 8, and the air flow supplied to the defrosting/refrigerator 1 can be adjusted. The air cleaning tower 6 has a built-in storage tank 9 for cleaning water, and a water supply pump pumps up water and sends the water to the heat exchanger 10. In the heat exchanger 10, the pumped water is heated by a hot water boiler 11 and exchanged with dry water at a predetermined temperature supplied by a hot water pump 12, and then sent to the air cleaning tower 6. In the turbo blower 7 of the cleaning tower 6, air taken from inside the warehouse and hot water sent from the heat exchanger 10 are mixed and adiabatically compressed while rotating at high speed. At this time, the hot water injected into the turbo blower 7 is crushed into fine particles to maximize the contact area with the air, and the particles that come into contact with the air and float in the air,
It efficiently adsorbs bacteria, spores, odors, etc. and cleans the air. At the same time, the air is heated (or warmed) to a predetermined temperature by contact with hot water and humidified.Furthermore, the mixed gas of water and air in the turbo blower 7 is centrifuged by rotation, and the water is transferred to the water storage tank 9. The air is compressed and exhausted to a gas-liquid separation chamber 13 connected to a turbo blower 7.

The compressed air exhausted into the gas-liquid separation chamber 13 is adiabatically expanded and cooled fJ], and the moisture in the air promotes the dew action and grows into larger particles that flow inside the gas-liquid separation chamber 13. The water droplets are sent to the outlet while rotating, and in the process, some of the water droplets come into contact with the wall of the gas-liquid separation chamber 13 and are discharged. The air thus dehydrated is thawed and circulated to the refrigerator 1 again. Next, inside the refrigerator, A-C is the temperature detection cord 14 installed inside.
The temperature inside the refrigerator is monitored during thawing, and if the temperature inside the refrigerator is lower than a predetermined temperature, the hot water pump 12 is activated to heat the refrigerator.
If the temperature is high, the operation is stopped and the temperature is maintained at a predetermined level. In addition, a core temperature detection element 15 is inserted into the inside of the frozen fish 4 installed in the refrigerator to detect the temperature at the center of the frozen fish 4, and when the temperature at the center reaches the maximum ice crystal formation temperature range, The temperature inside the refrigerator is lowered and maintained within a predetermined low temperature range (for example, 3°C to 5°C). Furthermore, the core temperature is within a predetermined vB freezing final temperature (-2°C ~
-1°C), the operation of the drought pump 12 is immediately stopped to stop heating the air supplied into the refrigerator. The above-mentioned temperature control inside the refrigerator is controlled by the central control unit.
This is done by a defrosting operation circuit built into the panel box 16. The control panel box 16 has a thawing operation circuit and a refrigeration operation circuit, and switches and controls the operation of the refrigerator 2 and the thawing fan 3 according to the purpose of each operation.

Next, when the frozen fish is to be continuously refrigerated after the thawing described in 1111 is completed, the refrigeration operation circuit is started, the temperature inside the refrigerator is detected by the temperature detection cable 14, and the temperature exceeds the predetermined refrigeration temperature. In this case, the freezer 2 belonging to the thawing/refrigerator 1 is operated to cool it down. Like the defrosting fan 3, the refrigerator 2 is equipped with a plurality of units, each of which uses a microcomputer built into the refrigeration operation circuit to control the cooling and heating required for a predetermined refrigeration temperature, and adjusts the internal temperature by inverter control. stabilize and maintain. In addition, the defrosting of freezer 2 is
A plurality of refrigerators 2 are operated alternately so that the temperature and humidity inside the refrigerator do not change.

The above is a method for cooling the refrigerator by supplying humidified clean air into the refrigerator.Next, when maintaining the temperature inside the refrigerator in the so-called freezing temperature range for refrigeration, supply humidified air into the refrigerator. Then, ice builds up, so the operation of the turbo blower 7 is stopped and the air supply to the inside of the refrigerator is stopped. Therefore, ice-temperature refrigeration is performed only by cooling the still air inside the refrigerator, but in this case, the temperature and humidity inside the refrigerator vary slightly.

The thawing device heats the air cleaning liquid and thereby controls the air temperature inside the freezer/refrigerator 1, but other types of thawing devices may also be used.

Figures 3 to 7 show a thawing system that controls the temperature inside the refrigerator by heating (or cooling) circulating air! A
It is a figure which shows another Example of a station. The thawing device according to this embodiment includes a gas cleaning tower B connected to a device A that requires air cleaning (corresponding to the freezer/refrigerator 1 in the above embodiment), and a gas cleaning tower B connected to the gas cleaning tower B to and a temperature controlled tIl device for controlling the humidity of the cleaning gas. The gas cleaning tower B includes a gas-liquid mixing section 21 that is connected to the discharge conduit A1 to the device and into which the gas to be cleaned is introduced, and a compression section 22 that rotationally compresses the gas-liquid mixture generated in the gas-liquid mixing section 21. , a cyclone 23 that circulates the gas-liquid mixture sent from the compression section 22 and performs gas-liquid separation, a lower compression section 24 that rotationally compresses the separated gas again, and a lower compression section 24 that rotates and compresses the separated gas again. It consists of a lower cyclone 25 that circulates the sent gas and supplies cleaning gas to the suction conduit A2 to the device, and performs two-stage gas compression and expansion operations.

The gas-liquid mixing section 21 consists of a hollow container having an introduction pipe 31 connected to the gas discharge conduit A1 of the device A, and inside this hollow container there is an outer cylindrical wall 32 hanging down from the ceiling and a wall 32 rising from the floor. A maze-like passage 3 partitioned by an inner cylinder wall 33
4,35. ．． 36 is formed, and the air to be cleaned first flows into the passage 34, then passes through the passage 35, and flows into the passage 36 in a meandering manner, as shown by the arrow in FIG. Each passage 34°3 is provided on the top surface of the gas-liquid mixing section 21.
A liquid sprayer 37 is installed corresponding to 5.36, and the liquid sprayed from this liquid sprayer 37 flows through the passage 34.
．． In the passage 36, the flow is parallel to the gas to be cleaned, while in the passage 35, it flows in a counter flow to the gas to be cleaned.

Further, a liquid discharge port 38 is provided at the bottom of the gas-liquid mixing section 21 to discharge the liquid dropped as a result of the primary gas cleaning inside the gas-liquid mixing section 21 to the outside.

The compression section 22 has a conical structure that gradually expands from the top to the bottom, and includes a casing 41 connected to the outlet portion of the passage 36 of the gas-liquid mixing section 21, and a centrifugal turbo feed III disposed inside the casing 41. It consists of a machine 42. Centrifugal turbo blower 4
2 uses a blower that rotates at an ultra-high speed and has rotary blades that bounce the gas-liquid mixture from the center of the bell body 41 toward the inner surface of the outer side wall. Further, a liquid discharge port 43 is provided at the bottom of the housing 41.

The cyclone 23 consists of a cylindrical fixed hollow body,
Inside the hollow body, there is an outer cylinder 51 having an opening 53 at a lower position.
and an inner cylinder 52 having an opening 54 at an upper position, a passage 55 is formed between the hollow inner cylinder and the outer cylinder 51, and a passage 55 is formed between the outer cylinder 51 and the inner cylinder 52. In addition, a passage 57 is formed inside the inner cylinder 52. 4
The upper part of the Noicron 23 is connected to the compression part 22 by the partition plate 45.
A plurality of openings 46 are formed by cutting out and bending the partition plate 45 in a portion that is partitioned from the lower end and corresponds to the passage 55, and the compression section 22 and the cyclone 23 are communicated with each other through the openings 46. . The opening 53 is also formed by cutting out the lower part of the outer cylinder 51 and bending this part. When forming the openings 46 and 53, the flow direction of the gas-liquid mixture from the compression part 22 to the cyclone 23 or from the passage 55 to the passage 56 is determined appropriately by considering the direction in which the notch is formed and the direction in which the notch is bent. can be determined. In this embodiment, the partition plate 45 includes:
As shown in FIG. 5, an opening 46 is formed in the outer cylinder 51 to block the airflow in the clockwise direction when viewed from above.
Similarly, an opening 5 that creates airflow in a counterclockwise direction when viewed from above.
3, the gas-liquid mixture passing through the passage 55 and the gas-liquid mixture passing through the passage 56 rotate in opposite directions. In addition, at the bottom of the cyclone 23, the cyclone 2
A liquid discharge port 58 is provided in which gas and liquid are separated.

A second stage compression section incorporating the centrifugal turbo feeder 1!1161, that is, a lower cyclone 25 having a lower compression section 24 and a cylindrical body 71 is disposed below the cyclone 23.

These lower compression section 24 and lower cyclone 25 have almost the same functions as the compression section 22 and cyclone 23,
The gas-liquid separation efficiency is improved by realizing a two-stage gas-liquid separation operation. Centrifugal turbo air blower! 11
42 and 61 are integrally attached to a shaft 27 rotatably supported by bearings 28 and 29 attached to the partition plate 45 and the cylindrical body 71, and a drive motor 26 connected to the base end of the shaft 27. By operating both centrifugal turbo blowers 42°61, it is possible to rotate at high speed. The lower cyclone 25 has an exhaust pipe 72 for discharging the cleaning gas, which exhaust pipe 72 is connected to the suction conduit A2 of the device A. Also, Figure 3 Innate 862.73
indicates a liquid discharge port for discharging the liquid separated into gas and liquid in each of the lower compression part 24 and the lower III li-icron 25.

The supply and discharge of gas cleaning liquid in this gas cleaning and temperature control device is performed by a liquid circulation device. This liquid circulation device consists of a tank 77 in which a liquid for gas-liquid mixing (usually water) is placed, and a top end connected to each liquid sprayer and a bottom end inserted into the water of the tank 77. A liquid recovery pipe 76 is connected to the supply pipe 78 for pumping up the liquid from the tank 77 and returns the liquid separated into the tank 77.

The tank 77 has a drain pipe 79 that is opened by a solenoid valve 83 to drain the liquid inside the tank 77 .
In order to supply new liquid to the tank, a liquid inlet pipe 80 is provided which is opened and opened by a solenoid valve 82, and the solenoid valve 82 is activated and deactivated by a float-type water level gauge 81 set above the liquid level. It is designed to be controlled.

Further, temperature control in this device is performed by a temperature control device 90 connected to the gas cleaning tower B. This temperature control device 90 includes a compressor 91 that compresses a low-temperature, low-pressure gas refrigerant, a four-way valve 92 that is connected to the compressor 91 and switches an inflow path 91a and an outflow path 91b of the refrigerant to the compressor 91, and a refrigerant generated by the compressor 91. The refrigerant is connected to the condenser 93, which cools the high-temperature, high-pressure gas refrigerant to the condensation point by heat radiation and reduces it to a high-pressure liquid. It consists of a liquid tank 94 that is kept in place, and an expansion valve 95 that is connected to the liquid tank 94 and rapidly expands the liquid refrigerant to form a low-temperature, low-pressure mist liquid. Expansion valve 95 is connected to conduit 96, while compressor 91 is connected to conduit 97.

In addition, in the gas cleaning tower, an outer cylinder wall 32 hanging from the ceiling surface of the gas-liquid mixing section 21 and an outer cylinder 5 inside the cyclone 23
1 has a double wall structure, forming first and second hollow circulation chambers 39 and 59, respectively, in which a refrigerant circulates. And conduit 9
6 is connected to the first circulation chamber 39, and a branch pipe 96a extends along the way to be connected to the second circulation EM chamber 59.

The connection position of the conduit 96.97 to the first circulation IM chamber 39 and the connection position of the conduit 96a, 97a to the five second circulation chambers are such that one is connected near the upper end of each circulation chamber 39.59, The other is connected near the bottom end, or the circulation chamber 3
Qffi
It is set in a relationship.

Electromagnetic valves 98 and 99 are respectively attached to the branch pipe 96a and a position ahead of the branch part of the conduit 96, and the first and second circulation chambers 39.
The flow rate of the refrigerant passing through the refrigerant 59 is controlled. Note that the electromagnetic valves 98 and 99 may be attached to the forward position of the branch part of the conduit 97 and the branch pipe 97a.

Furthermore, the motor 26. Pump 84. Solenoid valve 83°98.
The operation of each part of the compressor 99 and the compressor 91 is controlled by a central control unit 100 connected to each of these members. The central control unit 100 has substantially the same configuration as the control panel box 16 described above,
It has a temperature setting mechanism for setting the first thawing temperature and a temperature setting mechanism for setting the second thawing temperature.
is connected to a temperature sensor 101 that measures the core temperature of
Controls opening and closing of electromagnetic valves 83, 98, and 99.

In the gas cleaning and control device having such a configuration, the gas to be cleaned that flows from the device A through the introduction pipe 31 into the gas-liquid mixing section 21 of the gas cleaning tower B passes through the atomizer 37 while flowing through the passages 34, 35, and 36. Parallel flow cleaning in the passages 34 and 36 and counterflow cleaning in the passage 35 are alternately repeated by the sprayed liquid ejected from the passages 34 and 36. The sprayed liquid in the gas-liquid mixing section 21 is a mist with various particle sizes, and after large particles are fused with the gas, the gas is discharged from the liquid outlet 38 provided at the bottom of the gas-liquid mixing section 21. It will be discharged outside on the day of cleaning. Also,
The liquid microparticles are drawn into the centrifugal turbo blower 42 of the compression section 22 along with the gas flow while coming into contact with the gas.

Inside the centrifugal turbo blower 42, the gas-liquid mixture flows from the center to the outer periphery as shown by the arrows in the figure, and the liquid particles are crushed into fine particles by collision with the rotor blades rotating at high speed. At the same time, it mixes with and contacts the compressed gas, and adsorbs and removes substances, organisms, and gaseous bodies contained in the gas again.

Some of the liquid particles in the gas-liquid mixture are accelerated in the centrifugal direction by the rotation W during high-speed rotation, collide with the inner wall of the housing 41, and are separated from the gas. Due to the force of the collision and the fact that the side wall of the casing 41 has a conical structure, the oil particles gradually flow downward along the inner wall of the casing 41 and become large liquid particles that are discharged from the liquid discharge port 43. It is discharged outside the device.

This gas-liquid mixture is ejected into the passage 55 of the cyclone 23 through the opening 46 of the partition plate 45, and descends while swirling inside the passage 55. The gas compressed in the compression section 22 is fed into the cyclone 23, where it undergoes adiabatic expansion and is thereby subjected to a cooling effect. For this reason,
The fine particles in the saturated gas-liquid mixture serve as nuclei, causing the liquid components to condense and grow into liquid particles. In the cyclone 23, the gas-liquid mixture rotates clockwise and descends when looking inside the passage 55 from above, while the rotation direction is changed by the opening 53, rotates counterclockwise inside the passage 55, and then rotates upwards. It enters a passage 57 through the opening 54 and descends along this passage 57. During the circulation of this gas-liquid mixture,
The condensed and grown oil particles collect particles in the gas and are separated from the gas. This gas-liquid separated liquid gathers at the bottom of the cyclone 23 and is discharged from the liquid outlet 58 to the outside of the apparatus.

The gas separated into gas and liquid descends through the passage 57, is sucked into the lower compression part 24 connected to the lower part of the cyclone 23, is compressed again by the operation of the centrifugal turbo feeder 1!1ti61, and is entrained in the gas. The remaining liquid particles are separated and collected, and the liquid is discharged to the outside of the VAZi from the liquid discharge port 62 in the same manner as described above. On the other hand, the compressed gas enters the lower cyclone 25 while swirling, becomes F2 clean gas that separates and collects the remaining liquid particles, and passes through the gas suction pipe A2 connected to the lower υ cyclone 25. It is sent into device A. As a result, the air inside the apparatus A is gradually purified and the atmosphere is adjusted.

During this air cleaning operation, the central control unit 100
When the temperature is adjusted according to a command from the controller, the temperature control device 90 is activated. In the example of FIG. 3, the four-way valve 92
As a result of this operation, the compressor 93 is connected to the outlet path 91b of the compressor 91, so a cooling cycle is formed in this temperature control device 1ff90. Therefore, the refrigerant compressed by the compressor 91 radiates heat in the condenser 93, is adiabatically cooled in the expansion valve 95, and absorbs heat in the first and second circulation chambers 39,59. As a result, the gas to be cleaned flowing in the air cleaning tower B is cooled down to the set temperature. This temperature adjustment operation is appropriately controlled by the control operation at J3 in the central control unit 100, and the inside of the apparatus A is always maintained in an optimal state.

If the four-way valve 92 is rotated 90 degrees counterclockwise from the state shown in FIG. 3, the condenser 93 will be connected to the inflow path of the compressor 91 as shown in FIG. A heating cycle is formed.

As a result, the gas to be cleaned flowing in the gas cleaning tower B is warmed under the control of the central control unit 100 until it reaches the set temperature, and the temperature in the equipment ff1A is made optimal for thawing frozen products.

Next, an example of a defrosting operation using the defrosting apparatus according to the first and second embodiments will be described.

As already mentioned in the above explanation, FIG. 1 illustrates the progress of thawing and refrigeration carried out according to the present invention.
First, defrost/refrigerate 1. A: Frozen herring from Canada 10.0
00 kg was brought in and thawing began. The freezing temperature at the start of thawing was -20°C on average for both surface temperature and core temperature. At the same time as the thawing operation started, the hot water temperature of the hot water boiler was set to 60°C. The temperature of the washing water supplied to the air cleaning bath via the heat exchanger was set to 40°C, the temperature of the air exchanged with the washing water and supplied into the warehouse was set to 20°C, and the relative humidity was set to 95%. When the thawing operation starts, the air inside the refrigerator drops to 12
Although the temperature rapidly decreased due to heat exchange with the frozen fish 4 at 0°C, it quickly recovered by supplying fresh air at a ventilation rate of 60 times per hour. On the other hand, the freezing temperature of frozen fish 4 is the first
As shown in the figure, the patient quickly turned upside down. At this time, in order to bring the air inside the warehouse into even contact with the frozen fish 4 and thaw it efficiently, the thawing fan inside the warehouse was operated to accelerate the wind speed to 3 meters per second or more. Four hours after the start of thawing, the core temperature of frozen fish 4 rose to -5°C and reached the maximum ice crystal formation temperature range, so the internal temperature was automatically set and controlled at -5°C. Twelve hours after the start of thawing, the core temperature of the frozen fish 4 was -1.5° C., which reached the final thawing temperature, so heating of the supplied air was automatically stopped in response to an instruction from the core temperature sensor 15.

Since this frozen fish 4 needed to be kept refrigerated after it was thawed, it was connected to the refrigeration/driving circuit immediately after the thawing operation described above was completed, and the temperature inside the refrigerator was set to +3℃, and the humidity inside the refrigerator was 95%. Maintained at RH.

As a result of the above thawing and refrigeration operation, when we took out frozen fish 4 at 8am the next morning, 15 hours after the start of thawing, we found that the freshness of the herring with 9 eggs was almost the same as before freezing. There was no discoloration of the so-called root hairs, the bright red color of the blood was good, and there was almost no dripping due to thawing.

In addition, there was no abnormal odor that gave the impression of putrefaction in the refrigerator or in the frozen fish 4.

Next, when we look at the quality preservation of herring roe, which is the most important factor in thawing frozen 9 eggs, we find that even after thawing, the egg nucleus of the original sin is preserved in the same state as fresh fish, and the original sin that could not be solved by conventional thawing methods is preserved. No blood contamination from blood vessels was observed.

As a result, the commercial operations required at the normal processing stage are greatly omitted, and the N degree does not decrease until the end of the subsequent refrigeration process, resulting in significantly improved quality and yield of herring roe as a product compared to the conventional thawing method. It turned out that it was improving.

The above is an example of thawing frozen 9 eggs and herring, but similar effects have been verified for other frozen fish such as thawing trout, frozen mackerel, saury, squid, crab, and cod. It has become clear that it is extremely effective in maintaining freshness and quality and improving yield.

Effects of the Invention As described above, the present invention detects the internal temperature of frozen fish bodies and fish roe during thawing, controls the temperature of the cleaning and humidified air supplied to the thawing chamber, and reduces the temperature of the air inside the thawing chamber. The core temperature of thawed products is monitored, and the point at which the core temperature reaches the humidity in the maximum ice crystal formation temperature range that requires slow thawing is detected, and the internal temperature is controlled and maintained at a predetermined low temperature. Thawing automatically ends when the warm temperature reaches a predetermined thawing temperature, and following thawing, the thawed product is refrigerated in a low temperature, high humidity, and clean atmosphere. Extremely effective for thawing and refrigeration of frozen meat.

[Brief explanation of the drawing]

Figure 1 is a diagram showing how the temperature and humidity inside the thawing/refrigerator and the surface temperature and core temperature of the thawed product change over time when the thawing and refrigeration method according to the present invention is implemented, and Figure 2 is a schematic sectional view of a thawing device used in the present invention, FIG. 3 is a longitudinal sectional view of a thawing device according to a second embodiment of the present invention, and FIG. 4 is a front view showing the structure of a cyclone incorporated in the thawing device. Figure 5 is a view taken along the line v-■ in Figure 4 showing the partition plate covering the top surface of the cyclone, and Figure 6 is a sectional view taken along the line Vl-Vl in Figure 4 showing the lower frontage of the cyclone. , 7th
The figure is a diagram showing another operating state of the temperature control device in the second embodiment. 1... Thawing/refrigerator, 2... Freezer, 3... Thawing fan, 4... Frozen fish (product to be thawed), 5... Air duct, 6... Air cleaning tower, 7 ...Turbo blower, 8...Inverter motor, 9...Washing water tank, 10...Heat exchanger, 11...Hot water boiler, 1
2... Hot water pump, 13... Gas-liquid + m chamber, 14...
... Temperature detection element, 15 ... Core temperature sensor, 16 ...
・Control panel box (central control unit), 21... Gas-liquid mixing section, 22... Compression section, 2
3...Cyclone, 24...Lower compression section, 25...
・Lower cyclone, 26... Drive motor, 37...
Sprayer, 41... Housing, 42.61... Centrifugal turbo blower, 45... Partition plate, 46... Opening, 53...
- Opening, 90... Temperature control device, 100... Central control unit. Figure 11 SOID procedural amendment; q July 18, 1985

Claims (1)

[Scope of Claims] 1) A method of thawing an item frozen at a low temperature or an ultra-low temperature by blowing heated and humidified air thereon, the air temperature in the thawing/refrigerator is controlled and maintained at a first temperature. Heat is transferred to the interior of the thawed product while the surface remains frozen, and the core temperature of the thawed product is detected. When the core temperature reaches the maximum crystal formation temperature range of the tissue of the thawed product, the temperature inside the refrigerator is adjusted to the above-mentioned temperature range. Thawing of a frozen product characterized by slowly controlling and maintaining a second temperature lower than the first temperature, and further terminating the thawing when the core temperature reaches a predetermined final thawing temperature. Method. 2) In a method of thawing items frozen at low or ultra-low temperatures by blowing heated and humidified air, the air temperature inside the freezer/refrigerator is controlled and maintained at a first temperature to freeze the surface of the item to be thawed. When the core temperature of the product to be thawed is detected and the core temperature reaches the maximum crystal formation zone of the structure of the product to be thawed, the internal temperature is lowered to the first temperature lower than the first temperature. 2
Defrosting is performed slowly by controlling and maintaining the temperature at the specified temperature, and when the core temperature reaches the predetermined final defrosting temperature, defrosting is completed, and after the completion of defrosting, heating of the air blown into the refrigerator is stopped. A method for thawing and refrigerating frozen products, characterized in that the temperature inside the refrigerator is detected, the temperature is controlled to a predetermined refrigeration temperature, and the thawed products are refrigerated using cleaned, low-temperature, high-humidity air. 3) Stop heating the air, stop blowing air into the refrigerator, detect the air temperature inside the refrigerator, control and maintain the temperature inside the refrigerator at a predetermined freezing temperature range, and thaw the product. The method for thawing and refrigeration of frozen products according to claim 2, characterized in that the frozen products are refrigerated in a freezing temperature range.