JPH0799950A - Preezing of food and food freezing apparatus - Google Patents

Abstract

PURPOSE:To provide a food freezing method and a food freezing apparatus capable of shortening the freezing time of food, reducing the running cost and stabilizing the food in transfer and enabling the freezing of various kinds of foods. CONSTITUTION:This food freezing method comprises the mixing of an atmospheric gas in a freezing chamber 11 with a low-temperature liquefied gas by a cold air generation means to generate a freezing gas flow having controlled temperature and the contact of the freezing gas flow with a food 51 in the freezing chamber 11 to effect the freezing of the food. This food freezing apparatus is provided with a freezing chamber 11 and a cold air generation unit 31 placed in the freezing chamber and generating a freezing air flow in the chamber. The cold air generation unit 31 is provided with a casing 34 having a blowing port 32 and a suction port 33, an ejection nozzle 35 to eject a low-temperature liquefied gas into the casing 34, an atmospheric gas introducing machine 36 to introduce the atmospheric gas of the freezing chamber 11 into the easing 34 and a thermometer 37 to measure the cold air temperature in the casing 34. The blowing port 32 of the generation unit is directed toward the upper part of an endless rotor 22 of a conveyor unit 21 in the freezing chamber 11.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method and apparatus for freezing fresh and / or processed foods such as agricultural, livestock and marine products.

[0002]

2. Description of the Related Art As one of the methods for preserving fresh foods and processed foods, it is widely practiced to freeze these foods and refrigerate them, and when performing such food freezing on an industrial scale. , The air blast freezing method, the low temperature liquefied gas freezing method, the indirect brine contact freezing method, and a combination method thereof are often used.

In the case of the air blast freezing method, cold air generated by using a refrigerant circulation type heat exchanger and a blower is supplied into a freezer to freeze food. In the case of the low-temperature liquefied gas freezing method, refrigerant such as liquefied nitrogen and liquefied carbonic acid is directly injected from the injection nozzle in the freezer to freeze the food. In the case of the brine indirect contact freezing method, the food carried into the freezer via a belt conveyor is brought into contact with the brine in the freezer to be frozen.

[0004]

The respective freezing methods described above are
Although they have reached the fully matured technical field, the following problems remain in order to implement them rationally.
That is, in the case of the air blast freezing method, since the food is cooled by cold air depending on the heat exchanger, the freezing time of the food becomes long, and the quality of the food is deteriorated due to this, and the initial cost is also increased. Get higher In the case of the low temperature liquefied gas freezing method, since a large amount of expensive refrigerant is consumed, the running cost becomes high. In addition, since the low temperature liquefied gas adheres to the metal conveyor belt for food transportation in a liquid state, the conveyor belt is overcooled and causes local freezing, which causes troubles during food transportation. To do.
In the case of the brine indirect contact freezing method, since the food is frozen by contact with brine, it is not suitable for freezing foods with a small surface area (heat exchange area) or foods with uneven surface, and foods that should be frozen. Types are limited. Even when the air blast freezing method and the low temperature liquefied gas freezing method are used together,
Trouble of transportation equipment occurs due to freezing of the conveyor belt. Furthermore, when the low-temperature liquefied gas freezing method and the brine indirect contact freezing method are used together, not only troubles during food transportation but also the situation where the brine solidifies occurs.

[Object of the Invention] In view of the above technical problems, the present invention shortens the food freezing time, reduces the running cost, freezes a wide variety of foods, and freezes foods which can be stabilized during food transportation. A method and a food freezing device are provided.

[0006]

In order to achieve the intended purpose, the method for freezing food according to the present invention is designed so that, in a freezer in which food is carried in via a conveying means, an atmosphere gas in the freezer is used. The low temperature liquefied gas is mixed by a cold air generating means to generate a temperature controlled frozen air flow, and the frozen air flow is brought into contact with the food in the freezer to freeze the food.

In order to achieve the intended purpose, the food freezing apparatus according to the present invention comprises a freezer having an internal space for receiving food and an endless rotating body for carrying in and out food. Combined with a conveyor unit
And, in the food freezing device in which the endless rotating body of the conveyor unit extending inside and outside the freezer passes through the inlet of the freezer, the inside of the freezer, and the outlet of the freezer, for generating a frozen airflow in the freezer. A cold air generating unit, a casing having a blowout port and a suction port, an injection nozzle for injecting a low temperature liquefied gas into the casing, an atmosphere gas introduction machine for introducing the atmosphere gas in the freezer into the casing, A temperature measuring device for measuring the temperature of cold air in the casing, wherein the cold air generating unit is arranged in the freezer, and its outlet is directed to the endless rotating body in the freezer. To do.

In one embodiment of the food freezing apparatus according to the present invention, a forward-flowing cold air generating unit for generating a frozen air flow that advances in the direction of rotation of the endless rotary body and a direction of rotation of the endless rotary body are provided. A counter-current type cold air generating unit for generating a freezing air flow that goes backwards is arranged in the freezer, and the outlet of the forward-flowing cold air generating unit is directed to the endless rotating body at the inlet side of the freezer. Along with
The outlet of the counterflow type cold air generating unit is directed onto the endless rotating body on the outlet side in the freezer. In another embodiment of the food freezing apparatus according to the present invention, the upper portion of the endless rotary body in the freezer has a cold air circulation inlet at the end in the length direction and a cold air circulation outlet at the middle portion in the length direction. It is covered with a hood, and the outlet of the cold air generating unit is connected to the cold air circulation inlet of the hood. The outlet of the cold air generating unit in the above is formed by a duct as an example.
As another embodiment of the food freezing apparatus according to the present invention other than the above, a brine tank may be arranged below the endless rotating body in the freezer.

[0009]

In the food freezing method according to the present invention, the atmospheric gas (low temperature) and the low temperature liquefied gas (very low temperature) in the freezer are mixed in order to create a frozen air flow for freezing the food. The frozen flow thus obtained is composed of a mixed gas of a low-temperature gas and a cryogenic gas, and therefore has a control temperature (thermal equilibrium temperature) determined by the mixing ratio of these two gases, and the low-temperature liquefied gas contained in this is the atmosphere. Fully vaporized by mixing with gas. Therefore, the food can be rationally frozen in a short time by bringing the frozen air flow into contact with the food in the freezer.

In the food freezing apparatus according to the present invention, the cold air generating unit for generating the above-mentioned frozen air flow is arranged in the freezer, so that it can be used to freeze food in the same manner as described above. it can.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of a food freezing method / food freezing apparatus according to the present invention will be described with reference to FIG. In FIG. 1, 11 is a freezer having an internal space for receiving food, 21 is a conveyor unit for loading and unloading food into and out of the freezer, 31 is a cold air generating unit for generating a frozen air flow, and 41 is a control unit. Board, 51 shows food.

The freezer 11 is made of a well-known heat insulating wall material and has a box shape. An inlet 12 and an outlet 13 are formed on both sides of the freezer 11, and an exhaust port 18 is provided on the upper surface of the freezer 11. Are formed. Entrance 12 of freezer 11
The outlet 13 is covered with air curtains (air injection films) 16 and 17 formed by known or well-known air injectors 14 and 15 provided near them. An exhaust pipe 20 having an exhaust blower 19 is connected to the exhaust port 18 of the freezer 11.

The conveyor unit 21 includes an endless rotating body 2
2, a pair of driving wheel 23 and driven wheel 24, speed-adjustable electric motor (motor) 25, transmission belt 26, base 2
7 is a main constituent member, and a long tunnel-shaped hood 28 is a related constituent member. In the conveyor unit 21, a driven wheel 24 arranged outside the inlet 12 of the freezer 11 and a driving wheel 23 arranged outside the outlet 13 of the freezer 11 are rotatably supported by a base 27. The endless rotating body 22 wound around the driving wheel 23 and the driven wheel 24 is the inlet 1 of the freezer 11.
2. The inside of the freezer 11 and the inside and outside of the freezer 11 are rotated endlessly via the outlet 13 of the freezer 11, and the transmission belt 26 is disposed on the driving wheel 23 side of the conveyor unit 21. It is wound around an electric motor (motor) 25 and its driving wheel 23. As shown in FIG. 1, the tunnel-type hood 28 for covering the endless rotary body 22 of the conveyor unit 21 includes cold air circulation inlets 29a and 29b at both ends in the length direction, and cool air at the middle portion (center portion) in the length direction. It has circulation outlets 30a and 30b, and this is the freezer 11.
It is arranged inside and covers the upper portion (upward portion) of the endless rotary body 22. In the conveyor unit 21 described above, when the endless rotary body 22 is made of, for example, a metal belt (steel belt), a pulley type or roller type is used as the driving wheel 23 and the driven wheel 24. As another example, when the endless rotary body 22 is composed of a pair of parallel chain belts and a large number of metal belt pieces attached to these chain belts, a sprocket gear type driving wheel 23 and driven wheel 24 are used. Is used. The tunnel hood 28 may be made of any material, such as metal, synthetic resin, or a composite material thereof, regardless of the presence or absence of heat insulation.

In the case of the cold air generating unit 31, the air outlet 3
2, a casing 34 having a suction port 33, an injection nozzle 35, an atmosphere gas introducing device 36, and a temperature measuring device 37. The member forming the wall surface of the casing 34 and the like is also made of metal, synthetic resin, and / or a composite material thereof, with or without heat insulation. Casing 3
The blowout port 32 of No. 4 is formed by a duct. The injection nozzle 35 for injecting the low temperature liquefied gas is made of a ready-made product and is connected to a liquefied gas cylinder (not shown) via a pipe having a valve. Atmosphere gas introduction machine 3
6 is a well-known electric fan, and the temperature measuring device 37 is also a well-known one generally used for low temperature measurement. In the above, the injection nozzle 35 is provided inside the casing 34, and the atmosphere gas introducing device 36 is provided in the casing 34.
The temperature measuring instrument 37 is attached to the suction port 33 side of the casing 34, and the temperature measuring device 37 is attached to the inside of the air outlet (duct) 32 of the casing 34. Inside the freezer 11, two cold air generating units 31 thus assembled are arranged symmetrically. For convenience of explanation, when the one (forward flow type) cold air generating unit is 31A and the other (counterflow type) cold air generating unit is 31B, the outlet 32 of the cold air generating unit 31A is at the cold air circulation inlet 29a of the hood 28. The outlets 32 of the cold air generating unit 31B are respectively connected to the cold air circulation inlets 29b of the hood 28, and these outlets 32 are directed onto the endless rotary body 22 in the freezer 11.

The control board 41 receives the temperature measurement signal (gas temperature measurement signal in the casing 34) from the temperature measuring device 37, and injects the low-temperature liquefied gas by the injection nozzle 35 and the casing 34 by the atmospheric gas introducing device 36. This is for automatically controlling the amount of gas introduced into the chamber (intake amount), which controls the conveying speed of the food 51 by the endless rotary body 22 and the exhaust amount of the gas in the freezer by the exhaust blower 19. Functions are added as needed. Such a control panel 41
Is composed of a computer having a CPU as a main component, and is electrically or electronically connected to an obvious controlled device. As a control method based on the temperature measuring device 37 and the control panel 41, feedback control is adopted as an example, and PID control is adopted as another example.

As the food 51 to be frozen, fresh foods such as agricultural products (eg vegetables, fruits), livestock products (eg beef, pork, chicken), marine products (eg seafood), and / or
Alternatively, processed products thereof (eg, general processed foods, processed cereals, cooked products, various confectioneries including frozen desserts, dairy products) can be given.

When freezing food using the apparatus illustrated in FIG. 1, the following is given as an example. In the case of the conveyor unit 21, the electric motor 2 is connected via the transmission belt 26.
The rotation of No. 5 is transmitted to the endless rotary body 22, and the endless rotary body 22 is rotated clockwise in FIG. The rotation mode of the endless rotary body 22 may be continuous rotation or intermittent rotation.

In the case of both cold air generating units 31A and 31B, a low temperature liquefied gas (eg, liquefied nitrogen or liquefied carbonic acid) is injected into the casing 34 through these injection nozzles 35, and at the same time, an atmosphere gas introduction device 36 is used. Freezer 1
The atmospheric gas in 1 is introduced into the casing 34, and a mixed air flow of the low temperature liquefied gas and the atmospheric gas, that is, a frozen air flow is generated in the casing 34 of each cold air generating unit 31A, 31B. The low-temperature liquefied gas injected into the casing 34 is completely vaporized when it is mixed with the atmosphere gas inside the refrigerator, so that the low-temperature liquefied gas does not exist in the frozen air stream in the liquid state.

The frozen air flow on the cold air generating unit 31A side is
Outlet 32 of casing 34, cold air circulation inlet 29a of hood 28, inside hood 28, cold air circulation outlet 3 of hood 28
0a, etc., after passing through them, become the atmospheric gas in the freezer 11, and part of the atmospheric gas passes through the atmospheric gas introducing device 36 and the casing 3 on the side of the cold air generating unit 31A.
In order to be reintroduced into the freezer 4, the freezer 11 circulates through a predetermined path. The frozen airflow on the cold air generating unit 31B side is also the blowout port 32 of the casing 34, the cold air circulation inlet 29b of the hood 28, the inside of the hood 28, and the cold air circulation outlet 30 of the hood 28.
After passing through these, such as b, it becomes an atmospheric gas in the freezer 11, and a part of the atmospheric gas is introduced into the atmospheric gas introducing device 3
6, the casing 34 on the side of the cold air generating unit 31B
In order to be reintroduced into the inside, it circulates through a predetermined path in the freezer 11.

The temperature of each frozen air flow described above is measured by a temperature measuring device 37 provided in the air outlet 32 of each casing 34 at the initial stage of generation thereof, and the temperature measurement signal (electrical signal) is sent to the control panel 41. Is entered. Upon receiving the measurement signal, the control panel 41 determines whether or not each of the frozen air flows is within the set temperature range, and when these are different from the set temperature, the injection nozzle 35 and / or the atmospheric gas introducing device 36 are controlled. A predetermined control signal (electrical signal) is input to adjust the injection amount of low-temperature liquefied gas into the casing 34 and the intake amount, and each frozen air flow is maintained at a predetermined temperature according to the food 51 to be frozen. By the way, cold air generation unit 31B
T ₂ and the temperature T ₁ of the inside air outlet 32, the temperature T ₂ of the second half portion of the hood 28, in the operating condition in
Establish the relationship> T ₁ .

When the apparatus of FIG. 1 is in such an operating state, the food 51 placed on the endless rotary body 22 of the conveyor unit 21 enters the freezer 11 through the inlet 12 and the freezer 11 through the outlet 13. It passes through the inside of the hood 28 before it goes out. The food 51 in the freezer 11 is the food 28
When it is moving in the first half of the inside, it comes into contact with the frozen airflow (forward flow) from the forward-flow cold air generating unit 31A, and when it is moving in the latter half of the hood 28, the counter-current cold-air generating unit 3
It comes into contact with the frozen airflow (countercurrent) from 1B, and comes into contact with the frozen airflow in the vortex or turbulent state in the boundary region (the region where the forward flow and the countercurrent collide) in the first half and the latter half of the hood. Therefore, even if the food 51 has a complicated shape or has a small surface area (heat exchange area), the food 51 is blown from any direction such as forward flow, vortex flow, turbulent flow, and counterflow. It is frozen in a short time by the frozen air flow.
Moreover, since the low-temperature liquefied gas contained in the frozen air flow is completely vaporized, the low-temperature liquefied gas in the liquid state does not come into contact with the endless rotary body 22, and the food product caused by the local freezing of the endless rotary body 22 No transport problems occur.

In the freezing method of the present invention (combining the air blast method and the liquefied low temperature gas method), the conventional air blast method, and the conventional liquefied low temperature gas (LN ₂ ) method, the remaining two when the air blast method is set to 1 The running cost ratio of the method is as follows. Air blast method: Freezing method of the present invention = 1: 2.3 Air blast method: Liquefied low temperature gas method = 1: 3.5

The atmospheric gas in the freezer 11 when the food is frozen is exhausted to the outside from the exhaust port 18 and the exhaust pipe 20 via the exhaust blower 19 at appropriate or constant time. In this exhaust, in some cases, consideration must be given to avoid the deterioration of the work environment due to the exhaust gas.

The food 51 frozen as described above is transferred to the freezer 11 through the endless rotary body 22 of the conveyor unit 21.
After going out, if necessary, it is stored by refrigeration means.

Next, another embodiment of the food freezing method / food freezing apparatus according to the present invention will be described with reference to FIG. The embodiment shown in FIG. 2 is a combination of the cold air freezing means illustrated in FIG. 1 and the brine freezing means. Therefore, in this embodiment, the brine tank 38 is provided inside the freezer 11. It is located in. The brine tank 38 for cooling the brine includes, for example, a refrigerant circulation type heat exchanger, and the brine 39 contained in the brine tank 38 includes calcium chloride, sodium chloride, magnesium chloride, Methanol, denatured alcohol, ethylene glycol, glycerin, etc. are arbitrarily adopted. Of these, sodium chloride brine
Corrosion inhibitors may also be added.

In the embodiment shown in FIG. 2, two open brine tanks 38 are used. For convenience of explanation, one brine tank and brine are 38A and 39A, and the other brine tank and brine are 38B and 3A, respectively.
In the case of 9B, both brine tanks 38A and 38B are arranged adjacent to each other in the front and rear under the ascending portion of the endless rotating body 22, and the ascending portion of the endless rotating body 22 is disposed in the brine tank 38.
In contact with the brine 39A, 39B in A, 38B. The number of brine tanks arranged in the freezer 11 may be one or three or more.

In the embodiment of FIG. 2, the brine tank 38
Except for A, 38B and brines 39A, 39B, the other structure is substantially the same as that of the embodiment shown in FIG.

When the food product is frozen using the apparatus illustrated in FIG. 2, the conveyor unit 21 and the two cold air generating units 31A and 31B are brought into the same operating state as the case of FIG. In this case, the food 51 placed on the endless rotary body 22 of the conveyor unit 21 enters the freezer 11 through the inlet 12 and exits the freezer 11 through the outlet 13 until the endless rotary body 22 is reached. Both brine tanks 38A through 22,
It passes through the inside of the hood 28 while being in contact with the brine 39A and 39B in 38B. In the above, when the food product 51 moving in the first half of the hood 28 comes into contact with the brine 39A in the brine tank 38A while receiving the forward-flowing frozen airflow, and reaches the boundary region of the first half and the second half of the hood. Food 51 of the contact with the vortex, the turbulent frozen air flow,
The food 51 when moving in the latter half of the food 28 is
The brine tank 38B while receiving the frozen airflow in the countercurrent state
It contacts the brine 39B inside. Therefore, the food 51
Are frozen in a shorter time than the above as a synergistic effect of the cold air freezing action and the brine freezing action. Of course, since the frozen low-temperature liquefied gas does not contain the liquid-state low-temperature liquefied gas, not only the endless rotator 22 does not locally freeze when the food 51 is frozen, but also the brine 39A, 39B does not show an ice crystal state.

Next, another embodiment of the food freezing method / food freezing apparatus according to the present invention will be described with reference to FIG. In the embodiment shown in FIG. 3, a cold air generating unit 31 having a different mode from the above and a cold air generating unit 61 having a different mode from the above are arranged inside the freezer 11. In the case of the cold air generating unit 31 in FIG. 3, a jet nozzle 35 and a temperature measuring device 37 are provided in a casing 34 having a blowout port 32 and a suction port 33, and an atmospheric gas introducing device 36 is provided on the suction port 33 side of the casing 34. Unlike the duct described above, the air outlet 32 of the casing 34 is a simple opening. Such a cold air generating unit 31 is shown in FIG.
Those exemplified in can also be adopted. In the case of the cold air generating unit 31 illustrated in FIG. 4, the inside of the casing 34 is divided into two chambers R ₁ and R ₂ by the partition wall W having the passage P.
And an outlet 32 and a suction port 33 are formed in the chamber R ₂ . In the above, the injection nozzle 35 is provided in one chamber R ₁ , the temperature measuring device 37 is provided in the other chamber R ₂ , and the atmosphere gas introducing device 36 is attached to the suction port 33 side of the other chamber R _2. ing.

In FIG. 3, in the case of the cold air generating unit 61, a refrigerant circulation type heat exchanger 65 is provided in a casing 64 having a blowout port 62 on the lower surface and a suction port 63 on the upper surface, and suction of the casing 64 is carried out. The air blower type ambient gas introducing device 66 including the above-mentioned fan is attached to the mouth 63 side. As such a cold air generating unit 61, the one exemplified in FIG. 5 can also be adopted. In the case of the cold air generating unit 61 illustrated in FIG. 5, the casing 6 having the air outlet 62 on the lower surface and the suction ports 63 on the front and rear surfaces.
The heat exchanger 65 and the atmospheric gas introducing device 66 are provided in the inside of the No. 4, and the atmospheric gas introducing device 66 has
On the side.

Referring to FIG. 3, in the freezer 11, two cold air generating units 31, 61 are arranged, respectively. For convenience of explanation, one cold air generating unit is 31A,
When the other cold air generating unit is 31B, the remaining one cold air generating unit is 61A, and the other remaining cold air generating unit is 61B, each of these cold air generating units is on the ascending part of the endless rotary body 22 and is frozen. From the inlet 12 side to the outlet 13 side in the warehouse 11, 61A → 31A →
61B → 31B are arranged in this order, and these cold air generating units are connected to the outlets 32 of 31A, 31B, 61A, and 61B.
62 is directed onto the endless rotary body 22 in the freezer 11.

In the embodiment of FIG. 3, the hood 28 for covering the ascending portion of the endless rotary body 22 is omitted, but the brine tanks 38A and 38B are provided. Items omitted from the description in the embodiment of FIG. 3 are substantially the same as those of the above-described embodiments.

When freezing food by using the apparatus illustrated in FIG. 3, the conveyor unit 21 and the two cold air generating units 31A and 31B are put into the same operating condition as the case of FIG. 1, and the remaining two cold air generating units 61A. , 61B also rotate these atmospheric gas introducing devices 66 to bring them into an operating state. In this case, the food 51 placed on the endless rotary body 22 of the conveyor unit 21 enters the freezer 11 through the inlet 12 and generates cold air before it exits the freezer 11 through the outlet 13. Units 61A, 31A, 61B,
Brine 39 in both brine tanks 38A and 38B while receiving a predetermined frozen air flow blown out from 31B respectively.
B and 39B are brought into contact with each other and frozen by the cold air freezing action and the brine freezing action. When the food is frozen in this way, the temperature of the frozen air flow blown out from both cold air generating units 61A and 61B can also be controlled via the temperature control means (temperature measuring device, control panel, etc.).

[0034]

According to the food freezing method of the first aspect of the present invention, a temperature-controlled predetermined frozen air flow, that is, a mixed gas of an atmosphere gas and a low temperature liquefied gas in the freezer is frozen. Since it comes into contact with the food inside, the food can be frozen reasonably in a short time, and the initial cost can be reduced as compared with the conventional air blast method.
The running cost can be reduced as compared with the conventional liquefied low temperature gas system.

A food freezing apparatus according to a second aspect of the present invention comprises a casing having a blowout port, a suction port, a low temperature liquefied gas injection nozzle, an in-compartment atmosphere gas introducing device, and a frozen airflow temperature measuring device. Since the cold air generating unit is placed in the freezer and its outlet is directed onto the endless rotating body in the freezer, it can be used to reasonably freeze food in a short time. Moreover, since the low-temperature liquefied gas contained in the frozen air flow is completely vaporized, machine trouble due to local freezing of the endless rotary body does not occur, and stability in food transportation can be secured.

In the food freezing device according to the present invention, as described in claim 3, the blowout port of the forward flow type cold air generating unit is directed to the endless rotary body at the inlet side in the freezer, and the counterflow type device is provided. When the outlet of the cold air generating unit is directed onto the endless rotating body on the outlet side in the freezer,
The frozen air flow can be blown from any direction such as forward flow, vortex flow, turbulent flow, countercurrent flow, etc., so that a wide variety of foods including foods with complicated shapes and foods with a small surface area can be shortened by each frozen air flow. Can be frozen in time.

In the food freezing apparatus according to the present invention, as described in claim 4, when the upper part of the endless rotary body is covered with a hood for circulating cold air, the frozen air flow is passed through the hood. The food can be efficiently contacted.

In the food freezing apparatus according to the present invention, as described in claim 5, when the outlet of the cold air generating unit is formed by the duct, the frozen air flow is generated through the duct type outlet. It can be efficiently sprayed on food.

In the food freezing apparatus according to the present invention, as described in claim 6, when the brine tank is arranged in the freezer, the food is frozen by using the cold air freezing means and the brine freezing means in combination. Can be frozen in a short time.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a first embodiment of a food freezing method / food freezing apparatus according to the present invention.

FIG. 2 is a sectional view schematically showing a second embodiment of a food freezing method / food freezing apparatus according to the present invention.

FIG. 3 is a sectional view schematically showing a third embodiment of a food freezing method / food freezing apparatus according to the present invention.

FIG. 4 is a sectional view schematically showing another example of the cold air generating unit (for frozen air flow) used in the third embodiment of the present invention.

FIG. 5 is a perspective view schematically showing another example of the cold air generating unit (for air blast) used in the third embodiment of the present invention.

[Explanation of symbols]

 11 Freezer 12 Freezer Inlet 13 Freezer Outlet 21 Conveyor Unit 22 Endless Rotating Body 23 Driving Wheel 24 Driven Wheel 25 Electric Motor 26 Transmission Belt 27 Base 28 Hood 29a Cold Air Circulation Inlet 29b Cold Air Circulation Inlet 30a Cold Air Circulation Outlet 30b Cold Air Circulation outlet 31 Cold air generation unit (31A, 31B) 32 Air outlet 33 Suction port 34 Casing 35 Injection nozzle 36 Atmosphere gas introduction machine 37 Temperature measuring instrument 38 Brine tank (38A, 38B) 39 Brine (39A, 39B) 41 Control panel 51 Food 61 Cold air generating unit (61A, 61B) 62 Air outlet 63 Suction port 64 Casing 65 Heat exchanger 66 Atmosphere gas introduction machine

Claims (6)

[Claims] 1. In a freezer in which food is carried in via a transfer means, an atmosphere gas in the freezer and a low temperature liquefied gas are mixed by a cold air generating means to generate a temperature controlled frozen air flow, A food freezing method, characterized in that the frozen air is brought into contact with the food in a freezer to freeze the food. 2. A freezer having an internal space for receiving food and a conveyor unit provided with an endless rotating body for loading and unloading food into and out of the freezer are combined with each other, and a conveyor extending inside and outside the freezer. In the food freezing device in which the endless rotating body of the unit passes through the freezer inlet, the inside of the freezer, and the outlet of the freezer, the cold air generating unit for generating a frozen air flow in the freezer has an outlet and an outlet. A casing having a suction port, an injection nozzle for injecting a low-temperature liquefied gas into the casing, an atmosphere gas introduction device for introducing the atmosphere gas in the freezer into the casing, and a cold air temperature in the casing is measured. And a temperature measuring device for the cold air generating unit, wherein the cold air generating unit is arranged in the freezer, and its outlet is directed to the endless rotating body in the freezer. Food freezing device. 3. A forward-flowing cold air generating unit for generating a frozen air flow that is normal to the rotation direction of the endless rotary body, and a direction for generating a frozen air flow that is reverse to the rotation direction of the endless rotary body. The flow-type cold air generation unit is arranged in the freezer, and the outlet of the forward-flow type cold air generation unit is directed to the endless rotating body at the inlet side in the freezer and the counterflow-type cold air generation unit The food freezing device according to claim 2, wherein the air outlet is directed toward the endless rotary body on the outlet side in the freezer. 4. The upper part of the endless rotary body in the freezer is covered with a hood having a cold air circulation inlet at a longitudinal end and a cool air circulation outlet at a longitudinal middle portion. The food freezing device according to claim 2 or 3, wherein the outlet of the cold air generating unit is connected to the cold air circulation inlet. 5. The food freezing device according to claim 2, wherein the outlet of the cold air generating unit is formed by a duct. 6. The food freezing device according to claim 2, wherein a brine tank is arranged below the endless rotating body in the freezer.