CN109990543A - A kind of quick-freezing fresh-keeping method and tunnel type fresh-keeping quick-freezing machine - Google Patents

Abstract

The invention discloses a kind of quick-freezing fresh-keeping method and tunnel type fresh keeping refrigerators, including fixed frame, drive roller shaft and equipped with the library of foraminous conveyer, the library is arranged on fixed frame, it is equipped in the library and locks fresh room, freezing chamber, fresh room is mutually linked with freezing chamber, it locks fresh interior and is equipped with liquid nitrogen spraying device, liquid nitrogen spraying device is equipped with multiple atomizers；Air cooling equipment is equipped in freezing chamber；The library is equipped with the regulator control system being electrically connected between liquid nitrogen spraying device and air cooling equipment, and the library both ends are equipped with feed inlet and discharge port.The present invention is effectively combined using mechanical compression refrigeration with liquid nitrogen refrigerating; it first passes through spray liquid nitrogen and forms the freshness that frost protective layer protects material moisture not to be lost guarantee material in surface of material; the freezing of depth is carried out using mechanical compression refrigeration afterwards; it avoids air-cooled being dehydrated surface of material because directlying adopt; guarantee the freshness and mouthfeel of material, while having the effect of that lock is fresh fresh-keeping, according to the parameter set; fully automatic operation reduces energy consumption.

Description

A kind of quick-freezing fresh-keeping method and tunnel type fresh-keeping quick-freezing machine

technical field

The invention relates to a quick-freezing machine, in particular to a quick-freezing and fresh-keeping method and a tunnel-type fresh-keeping quick-freezing machine mainly used for foods such as vegetables and fruits.

Background technique

The quick-freezer is a device used for quick-freezing of food in the food processing industry. It has a wide range of applications in the food processing industry. The refrigeration methods of the food quick-freezer in the prior art mainly include mechanical compressor refrigeration and liquid nitrogen refrigeration. Most manufacturers use the conventional mechanical compression refrigeration method. This method uses the fan to blow the cold air to the material to achieve the effect of freezing. However, the refrigeration time of this refrigeration method is longer and the energy consumption is increased. Continuous blowing to the food causes more water loss on the surface of the food, which easily leads to dehydration on the surface of the material, which greatly reduces the freshness and taste of the food. Especially for some foods that require high freshness and taste, such as vegetables, fruits and meat, in order to achieve a good quick-freezing effect and reduce the loss of food moisture, liquid nitrogen has now appeared on the market to replace the traditional refrigeration system to quick-freeze food. , Based on the extremely low temperature characteristics of liquid nitrogen -196 ℃, it can quickly form frost on the surface of the food to lock the moisture, effectively protect the surface of the food from dehydration, and ensure the freshness and taste of the food. Incomparable, it can also reduce the loss of water due to the strong wind required by traditional mechanical freezing. However, when using liquid nitrogen for quick freezing, all liquid nitrogen is used for quick freezing, which makes the consumption of liquid nitrogen very large. , resulting in increased costs. The above two most commonly used quick freezing methods have their own advantages and disadvantages, which affect the optimal use of customers.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the present invention proposes a quick-freezing and fresh-keeping method and a tunnel-type fresh-keeping quick-freezing machine, which effectively combine the traditional mechanical compression refrigeration method with the liquid nitrogen refrigeration method. A layer of frost protection layer maintains the freshness of the food, and then uses mechanical compression refrigeration for deep freezing, avoiding the dehydration of the food surface due to direct air cooling, ensuring the freshness and taste of the food, and at the same time, it has the effect of locking and preserving freshness.

In order to achieve the above purpose, the technical solutions provided by the present invention are as follows: a tunnel type fresh-keeping quick-freezing machine, comprising a fixed frame, a transmission roller shaft and a storage body provided with a conveying mesh belt, and the two ends of the storage body are provided with a supply mesh belt for conveying. Through the feeding port and the discharging port, the storage body is arranged on the fixed frame, and the storage body is provided with a fresh-locking chamber and a freezing chamber, and the fresh-locking chamber is arranged at the front end of the freezing chamber and is connected with the freezing chamber. , a liquid nitrogen spraying device is arranged in the fresh-locking chamber, and a plurality of atomizing nozzles are arranged on the liquid nitrogen spraying device; an air cooling device is arranged in the freezing chamber; A control system for the electrical connection between the spray device and the air cooling device.

As a further improvement of the present invention, the regulation system includes a liquid nitrogen delivery pipe, a controller, a temperature sensor and a position sensor, the liquid nitrogen delivery pipe extends to the outside of the reservoir and is connected to a liquid nitrogen storage tank, and the liquid nitrogen delivery pipe is connected to a liquid nitrogen storage tank. The liquid nitrogen spraying device is fixed on the inside of the fresh-locking box corresponding to the top of the conveying mesh belt through a fixing rod, and a solenoid valve is provided at the connection between the spraying device and the liquid nitrogen conveying pipe. The temperature sensor is evenly distributed in the fresh-locking chamber and the freezing chamber along the length of the conveyor belt, and the position sensor is arranged on one side of each temperature sensor. The temperature sensor, the position sensor and the solenoid valve are all connected with the The controller is electrically connected. The control system uses position sensors, temperature sensors, etc. to globally control the freezing temperature of the entire quick-freezer, and detects that the quick-freezer starts to work on the conveyor belt. The liquid nitrogen spraying device can evenly spray liquid nitrogen on the surface of the material. The characteristics of liquid nitrogen can quickly form frost on the surface of the material to protect the moisture in the material from loss.

Preferably, in order to ensure that the atomizing nozzle has a good spraying effect, the upper end of the atomizing nozzle is provided with a pipeline connection port, the interior is provided with a spiral trunk through hole connected with the pipeline connection port, and the lower end is provided with an air injection hole, so The air injection hole is connected with a matching branch through hole, and the other end of the branch through hole is connected to the end of the spiral trunk through hole.

Further, the air-cooling device includes multiple sets of evaporators, the evaporators are provided with a fan and a refrigerant interface, the refrigerant interface extends to the outside of the freezing box to connect to the refrigeration equipment, and the evaporator is fixed on the conveyor mesh belt through a bracket. Above, the upper end of the evaporator is connected and fixed with the freezer box through the fixing rod, the upper part of the evaporator is provided with a sealing plate, the evaporator is provided with an air outlet corresponding to the conveying mesh belt downward, and the air outlet is provided with a shunt plate to evaporate the evaporator. A pair of fans is arranged on one side of the evaporator corresponding to the length direction of the conveyor mesh belt, and a wind shield connected with the sealing plate is arranged on the other side. The evaporator adopts the mechanical compression refrigeration method, and the low-temperature cold air is continuously blown to the material through the fan, which can better deeply freeze the material and further ensure the quick-freezing quality of the food.

Preferably, in order to more intuitively reflect the display of the internal temperature of the quick-freezing machine, the control system further includes a man-machine interface for displaying the temperature detected by each temperature sensor.

Preferably, in order to make the cold air circulate in all directions to freeze the materials and ensure that the storage body has good heat preservation, the storage body material is made of high-quality polyurethane foam and double-sided stainless steel plate, and the storage body is provided with multiple A deflector bent towards the conveyor belt.

Further, in order to ensure the reliability of material transportation by the quick-freezing machine, the transmission roller shaft can be connected to both ends of the fixed frame by rotating around its own axis, and the conveying mesh belt is tensioned and connected to the transmission roller shaft. There are several roller shafts between the drive rollers, and the conveying mesh belt is powered by a synchronous drive motor.

The quick-freezing and fresh-keeping method based on the above-mentioned a kind of tunnel type fresh-keeping quick-freezing machine comprises the following steps:

Stage 1: Liquid nitrogen pre-freezing and fresh-locking stage. First, the washed and drained materials to be frozen are placed on the conveyor mesh belt at the front end of the feeding port. The conveyor mesh belt sends the materials into the fresh-locking chamber. After the set position sensor detects that there is material entering the fresh-locking room, it feeds back the signal to the controller, and the controller sends an instruction to the solenoid valve to open the liquid nitrogen valve. It can quickly form a layer of frost on the surface of the material to lock the moisture inside the material;

The second stage: the air-cooled deep-freezing stage, after the material passes through the processing process of the fresh-locking room, it enters the freezer with the conveyor mesh belt, and there is an evaporator in the freezer. For deep freezing, after the two processes are processed, the material discharge temperature reaches the requirement, it is discharged from the discharge port, and it can be packaged and stored at the corresponding temperature.

The beneficial effects of the invention are as follows: liquid nitrogen has the characteristics of good effect of freezing and fast fresh-keeping. The invention divides the freezing process into two stages: liquid nitrogen quick-freezing and fresh-keeping and air-cooled deep quick-freezing. Nitrogen quickly forms a layer of frost on the surface of the material, thereby locking the moisture inside the item, entering the air-cooled deep quick freezing stage and then freezing the entire item. Through the control system, the internal temperature of the quick freezer can be automatically adjusted according to the set temperature. , obtain real-time temperature parameters through the temperature sensor, and adjust the spray amount of liquid nitrogen and the wind power of the fan by the controller, which not only reduces the dry consumption during the quick-freezing process, but also improves the food quality. The automatic temperature control improves the quick-freezing efficiency and saves resources. The traditional mechanical compression refrigeration method is effectively combined with the liquid nitrogen refrigeration method, which further shortens the freezing time, and the time ratio of liquid nitrogen spraying and cold air quick freezing can be adjusted according to the characteristics of the material; the internal circulation mechanism is adopted to reduce the burden of the air cooler; When the quick-freezer detects that there is no food on the conveyor belt, each nozzle will not release liquid nitrogen in advance, which can reduce the consumption of liquid nitrogen and energy consumption; the speed of the conveyor belt can be adjusted according to the conditions of the items to be frozen. , Increase the amount of liquid nitrogen sprayed and the freezing time of the fan wind speed adjustment stage, flexible use and wide application range. The combination of liquid nitrogen quick-freezing and mechanical compression air-cooled quick-freezing not only ensures that the consumption of liquid nitrogen will not increase, but also solves the disadvantage of directly using the air-cooled quick-freezing method to cause moisture loss of materials, reducing costs and increasing efficiency to ensure food. of the best quality.

Description of drawings

For ease of description, the present invention is described in detail by the following preferred embodiments and accompanying drawings.

Fig. 1 is a kind of quick-freezing fresh-keeping method of the present invention and the structure diagram of tunnel type fresh-keeping quick-freezing machine;

Fig. 2 is a kind of quick-freezing fresh-keeping method of the present invention and the top view of tunnel type fresh-keeping quick-freezing machine;

Fig. 3 is a kind of quick-freezing and fresh-keeping method of invention and the structure diagram of tunnel type fresh-keeping quick-freezing machine air-cooling device;

Fig. 4 is a kind of quick-freezing preservation method and the structure diagram of the atomizing nozzle of tunnel type fresh-keeping quick-freezing machine of invention;

5 is a sectional view of the upper end structure of the atomizing nozzle of a quick-freezing and fresh-keeping method and a tunnel-type fresh-keeping quick-freezing machine according to the invention.

In the picture: fixed frame-1; drive roller-2; storage body-3; conveyor mesh belt-4; liquid nitrogen spray device-5; air cooling device-6; fixed rod-7; solenoid valve-8; guide Flow plate-9; synchronous drive motor-11; transmission wheel-12; fresh-locking chamber-31; freezing chamber-32; atomizing nozzle-51; 35; controller-36; temperature sensor-37; position sensor-38; evaporator-61; fan-611; refrigerant interface-612; bracket-62; sealing plate-613; air outlet-614; manifold-615; Human-machine interface-39; bearing-21; windshield-616; shock device-41, air jet hole-511, pipeline connection port-512, spiral trunk through hole-513, branch trunk through hole-514.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

As shown in Figures 1, 2, 4, and 5, a tunnel type fresh-keeping quick-freezing machine includes a fixed frame 1, a transmission roller shaft 2 and a storage body 3 provided with a conveying mesh belt 4, and the storage body 3 is arranged on the fixed frame 1, the storage body 3 is provided with a fresh-locking chamber 31 and a freezing chamber 32, the fresh-locking chamber 31 and the freezing chamber 32 are connected to each other, and a liquid nitrogen spray device 5 is arranged in the fresh-locking chamber 31, so The liquid nitrogen spray device 5 is provided with a number of atomizing nozzles 51, the upper end of the atomizing nozzle 51 is provided with a pipeline connection port 512, and the interior is provided with a spiral trunk through hole 513 connected with the pipeline connection port 512. An air injection hole 511 is provided, the air injection hole 511 is connected with a matching branch through hole 514 , and the other end of the branch through hole 514 is connected to the end of the spiral main through hole 513 . The freezer compartment 32 is provided with an air-cooling device 6; the storage body 3 is provided with a control system that is electrically connected between the liquid nitrogen spray device 5 and the air-cooling device 6, and both ends of the storage body 3 are provided with There are feed openings 33 and discharge openings 34 for the conveying mesh belt 4 to pass through; the transmission roller shaft 2 can rotate around its own axis and is connected to both ends of the fixed frame 1, and the transmission roller shaft makes the transmission mesh belt easy There are several transmission wheels 12 between the lower end of the fixed frame 1 and the conveying mesh belt 4, the conveying mesh belt 4 is tensioned and connected to the transmission roller shaft 2, and a number of bearings are arranged between the transmission roller shafts 2 21. The conveyor mesh belt 4 is powered by the synchronous drive motor 11. In order to prevent the material from sticking to the transmission mesh belt 4 in actual work, a shock device 41 is added to the transmission mesh belt 4 to prevent the material from sticking to slight vibration. On the transmission mesh belt, the transmission mesh belt is stainless steel mesh belt, the chain center width is 2500mm, the wire diameter of the conveyor belt is 1.5mm, the string rod is 8mm, the pitch is 3.5mm, and it is equipped with a 1-inch double-pitch chain.

The control system on the storage body 3 includes a liquid nitrogen delivery pipe 35, a controller 36, a temperature sensor 37 and a position sensor 38. The liquid nitrogen delivery pipe 35 extends to the outside of the storage body 3 and is connected to a liquid nitrogen storage tank (not marked) , the liquid nitrogen conveying pipe 35 is connected to the liquid nitrogen spraying device 5, and the liquid nitrogen spraying device 5 is fixed on the inside of the fresh-locking chamber 31 corresponding to the top of the conveying mesh belt 4 through the fixing rod 7, and the spraying The connection between the shower device 5 and the liquid nitrogen conveying pipe 35 is provided with a solenoid valve 8; the temperature sensor 37 is evenly distributed in the fresh-locking chamber 31 and the freezing chamber 32 along the length of the conveying mesh belt 4, and the temperature sensor is convenient for detecting the processing temperature, and the temperature in the warehouse, and the detected temperature is fed back to the controller 36 at the same time, the position sensor 38 is arranged on one side of each of the temperature sensors 37, and the position sensor 38 is used to detect whether there is any material on the conveyor belt 4 When there is no material, the signal is transmitted to the controller 36, and the controller 36 is controlling the solenoid valve 8 to control the wind force of the atomizing nozzle 51 and the evaporator 61. The temperature sensor 37, the position sensor 38 and the solenoid valve 8 are all connected with the The controller 36 is electrically connected; the controller 36 is connected with a man-machine interface 39 for displaying the temperature detected by each temperature sensor 37, and the man-machine interface displays the real-time temperature, which is convenient to control the quick-freezing machine, and the control system can make the quick-freezing machine in the After feeding to quick freezing, the discharging is fully automatic, with less manual intervention. It is only necessary to input the freezing parameters in advance according to the characteristics of different materials. The transmission system adopts frequency conversion speed regulation, and each electrical appliance is equipped with separate control switches in the controller.

As shown in FIG. 3 , the air-cooling device 6 includes a plurality of evaporators 61 . The evaporators 61 are provided with a fan 611 and a refrigerant interface 612 , and the refrigerant interface 612 extends to the outside of the freezer compartment 32 to be connected to refrigeration equipment (not shown). The evaporator 61 is fixed above the conveying mesh belt 4 through the bracket 62, the upper end of the evaporator 61 is connected and fixed with the freezing chamber 32 through the fixing rod 7, the upper part of the evaporator 61 is provided with a sealing plate 613, and the evaporator 61 faces downwards. Corresponding to the conveyor belt 4, an air outlet 614 is provided, and the air outlet 614 is provided with a distribution plate 615. The evaporator 61 is provided with a pair of fans 611 on one side corresponding to the length direction of the conveyor belt 4, and a sealing plate 613 on the other side. For the connected air baffles 616 , the fans 611 on the adjacent evaporators 61 are disposed opposite to each other, and the blowing direction of the fans 611 is toward the corresponding evaporator 61 .

Preferably, the material of the storage body 3 is made of high-quality polyurethane foam and double-sided stainless steel plate, so that the storage body has a good thermal insulation function, and the storage body 3 is provided with a plurality of deflectors bent toward the conveying mesh belt. 9. Let the air-conditioning circulate in the warehouse to reduce energy consumption.

A method for quick-freezing and fresh-keeping, comprising:

The first stage: the liquid nitrogen pre-freezing and fresh-locking stage. First, the washed and drained materials to be frozen are placed on the conveyor mesh belt 4 at the front end of the feeding port 33, and the conveyor mesh belt 4 sends the materials into the fresh-locking chamber 31. After the position sensor 38 arranged at the front end of the fresh-locking chamber 31 detects that the material enters the fresh-locking chamber 31, the signal is fed back to the controller 36, and the controller 36 sends an instruction to the solenoid valve 8 to open the liquid nitrogen valve, and the liquid nitrogen is atomized by the liquid nitrogen. The sprinkler 51 is evenly sprayed in the fresh-locking chamber 31, and a layer of frost is quickly formed on the surface of the material through liquid nitrogen spray freezing to lock the moisture inside the material;

The second stage: the air-cooled deep-freezing stage, after the material passes through the processing process of the fresh-locking chamber 31, it enters the freezing chamber 32 along with the conveying mesh belt 4. There is an evaporator 61 in the freezing chamber 32, and the fan 611 set on the evaporator 61 continues continuously. The cold air is blown to the material and deep freezing is carried out. After the material discharge temperature reaches the required temperature after processing in two processes, it is discharged from the discharge port 34, and it can be packaged and stored at the corresponding temperature.

In the existing technology, there are also examples of freezing the surface of the material to lock the moisture, but most of them are in two cases: the first is the single use of liquid nitrogen for freshness and quick freezing. Although this method is fast and effective, the The consumption is also large, which leads to an increase in cost, which is not conducive to the development of the enterprise; the second is to first freeze the surface of the material through the first air-cooling and quick-freezing to achieve the effect of locking in moisture, and then deep-freezing through air-cooling to achieve the final result. However, this technology does not fundamentally solve the problem that the cold air will dry the moisture on the surface of the material, although the surface freezing can be achieved by reducing the wind speed, which will reduce the efficiency, increase the time consumption, and increase the energy consumption. Conducive to the development of the enterprise, does not meet the current market demand.

The technical scheme of the present invention adopts the combination of liquid nitrogen quick-freezing and mechanical compression air-cooling quick-freezing, which not only ensures that the consumption of liquid nitrogen will not increase, but also solves the drawback of directly using the air-cooling and quick-freezing method to cause moisture loss of materials, and reduces the cost. , increasing the quick-freezing efficiency and reducing the time used for quick-freezing, ensuring the best quality of food. In the technical scheme of the present invention, the freezing process is divided into two stages: liquid nitrogen quick-freezing and fresh-keeping and air-cooling deep quick-freezing. In the liquid nitrogen quick-freezing and fresh-keeping stage, liquid nitrogen can quickly form a layer of frost protection layer on the surface of the item, thereby locking moisture in Inside the item, and then enter the air-cooled deep-freezing stage to freeze the entire item. Through the control system, the internal temperature of the quick-freezer can be automatically adjusted according to the set temperature, and the injection volume of liquid nitrogen and the wind power of the fan can be adjusted correspondingly through the temperature sensor. Not only The dry consumption during the quick-freezing process is reduced, the quality of the quick-frozen food is improved, and the automatic temperature control improves the quick-freezing efficiency and saves resources; the traditional mechanical compression refrigeration method is effectively combined with the liquid nitrogen refrigeration method, which further shortens the freezing time, and The time ratio of liquid nitrogen spray and cold air quick-freezing can be adjusted according to the characteristics of the material; the internal circulation mechanism is adopted to reduce the burden of the air cooler; when the quick-freezer detects that there is no food on the conveyor belt, the nozzles will not advance. The release of liquid nitrogen can reduce the consumption of liquid nitrogen and reduce energy consumption; according to the conditions of the items to be frozen, by adjusting the speed of the conveyor belt, the amount of liquid nitrogen sprayed and the freezing time of the fan wind speed adjustment stage can be increased, and the use is flexible and has a wide range of applications. . The invention can greatly improve the quick-freezing efficiency of materials, ensure fresh quality, save energy consumption, and meet the needs of market development at the current stage.

The above content is a limitation on the protection scope of the present invention in combination with the specific preferred embodiments. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art can make various modifications without creative work. Or deformations are still within the protection scope of the present invention.

Claims (8)

1. A tunnel-type fresh-keeping quick-freezer, comprising a fixed frame (1), a transmission roller shaft (2), and a storage body (3) provided with a conveying mesh belt (4), and both ends of the storage body (3) are provided with The feeding port (33) and the discharging port (34) for the conveying mesh belt (4) to pass through, the storage body (3) is arranged on the fixing frame (1), and it is characterized in that: the storage body (3) ) is provided with a fresh-locking chamber (31) and a freezing chamber (32), the fresh-locking chamber (31) is arranged at the front end of the freezing chamber (32) and is mutually connected with the freezing chamber (32). ) is provided with a liquid nitrogen spray device (5), the liquid nitrogen spray device (5) is provided with a plurality of atomizing nozzles (51); the freezing chamber (32) is provided with an air cooling device (6) ); the storage body (3) is provided with a control system electrically connected with the liquid nitrogen spray device (5) and the air cooling device (6). 2. A tunnel type fresh-keeping quick-freezer according to claim 1, characterized in that: the control system on the storage body (3) comprises a liquid nitrogen delivery pipe (35), a controller (36), a temperature sensor ( 37) and a position sensor (38), the liquid nitrogen delivery pipe (35) extends to the outside of the storage body (3) and is connected to a liquid nitrogen storage tank, and the liquid nitrogen delivery pipe (35) is connected to the liquid nitrogen spray The device (5), the liquid nitrogen spray device (5) is fixed on the inside of the fresh-locking chamber (31) corresponding to the top of the conveyor mesh belt (4) through the fixing rod (7). A solenoid valve (8) is arranged at the connection of the liquid nitrogen conveying pipe (35); the temperature sensor (37) is evenly distributed in the fresh-locking chamber (31) and the freezing chamber (32) along the length of the conveying mesh belt (4), The position sensor (38) is arranged on one side of each temperature sensor (37), and the temperature sensor (37), the position sensor (38) and the solenoid valve (8) are all connected to the controller (36) electrical connection. 3. The tunnel-type fresh-keeping quick-freezer according to claim 1, characterized in that: the upper end of the atomizing nozzle (51) is provided with a pipeline connection port (512), and the interior is provided with a pipeline connection port (512). ) connected spiral trunk through hole (513), the lower end is provided with an air injection hole (511), the air injection hole (511) is connected with a matching branch trunk through hole (514), and the other branch trunk through hole (514) One end is connected to the end of the helical trunk through hole (513). 4. A tunnel-type fresh-keeping quick-freezer according to claim 1, characterized in that: the air cooling device (6) comprises multiple sets of evaporators (61), and a fan (61) is provided on the evaporator (61). 611) and the refrigerant interface (612), the refrigerant interface (612) extends to the outside of the freezer compartment (32) to connect the refrigeration equipment, and the evaporator (61) is fixed above the conveyor belt (4) through the bracket (62), The upper end of the evaporator (61) is connected and fixed with the freezer compartment (32) through the fixing rod (7). The upper part of the evaporator (61) is provided with a sealing plate (613), and the evaporator (61) corresponds to the conveying mesh belt downward. (4) An air outlet (614) is provided, the air outlet (614) is provided with a distribution plate (615), and a pair of fans (611) are provided on one side of the evaporator (61) corresponding to the length direction of the conveyor belt (4) , the other side is provided with a windshield (616) connected to the sealing plate (613), the fans (611) on the adjacent evaporators (61) are arranged opposite, and the blowing direction of the fans (611) is towards the corresponding evaporator (61). 5 . The tunnel type fresh-keeping quick-freezer according to claim 2 , wherein the controller ( 36 ) is connected with a man-machine interface ( 39 ) for displaying the temperature detected by each temperature sensor ( 37 ). 6 . 6. A tunnel type fresh-keeping quick-freezing machine according to claim 1, characterized in that: the material of the storage body (3) is made of high-quality polyurethane foam and double-sided stainless steel plate, and the inside of the storage body (3) is There are a plurality of deflectors (9) bent towards the conveying mesh belt 4. 7. A tunnel type fresh-keeping quick-freezer according to claim 1, characterized in that: the drive roller shaft (2) is connected to both ends of the fixed frame (1) rotatably around its own axis, and the fixed frame ( 1) Several transmission wheels (12) are arranged between the lower end and the conveying mesh belt (4), the conveying mesh belt (4) is tensioned and connected to the transmission roller shaft (2), and the transmission roller shaft (2) is A number of bearings (21) are arranged therebetween, and the conveying mesh belt (4) is powered by a synchronous drive motor (11). 8. A method for quick-frozen preservation, characterized in that, comprising: Stage 1: Liquid nitrogen pre-freezing and fresh-locking stage. First, the washed and drained materials to be frozen are placed on the conveyor mesh belt (4) at the front end of the feed inlet (33), and the materials are transported by the conveyor mesh belt (4). After entering the fresh-locking chamber (31), the position sensor (38) provided at the front end of the fresh-locking chamber (31) detects that the material enters the fresh-locking chamber (31), and then feeds back the signal to the controller (36), and the controller (36) Send an instruction to the solenoid valve (8) to open the liquid nitrogen valve, and the liquid nitrogen is evenly sprayed into the fresh-locking chamber (31) through the liquid nitrogen atomizing nozzle (51). The liquid nitrogen can quickly form a layer of frost on the surface of the material, locking the material. internal moisture; The second stage: the air-cooled deep-freezing stage, after the material passes through the processing process of the fresh-locking chamber (31), it enters the freezing chamber (32) along with the conveying mesh belt (4), and there is an evaporator (61) in the freezing chamber (32), The fan (611) set on the evaporator (61) continuously blows the low-temperature cold air to the material for deep freezing. After the two processes are processed, the material discharge temperature reaches the requirement, and the material is discharged from the discharge port (34), packed and placed. Store at the appropriate temperature.