55results about How to "Increase freezing rate" patented technology

An ice making machine comprising a housing, an evaporator connected to a freezing system, a base frame having a lower surface and a multiplicity of freezing cells for retaining water to be frozen, a freezing base plate provided adjacent to the evaporator and the freezing base plate having freezing fingers formed on the lower surface of the freezing base plate to be dipped into the water retained by the freezing cells, and an ultrasonic transducer for removing air bubbles inside the water by vibrating the water contained in the freezing cells with ultrasonic waves. The ultrasonic transducer preferably is disposed on the lower surface of the base frame.

A method for improving the unfreezing quality of fast frozen fruit and vegetables with low-frequency ultrasonic belongs to the processing technical field of fruit and vegetable food. The present invention adopts ultrasonic for freezing in the process of fast freezing; the process is that the raw materials of fruit and vegetables are selected, cleaned and burnt to kill the enzyme; and then the materials are cooled, refrigerated and frozen with ultrasonic; at last the materials are packed up. The present invention adopts the process that the ultrasonic processing is combined in the process of dipping and freezing fruit and vegetable and improves the unfreezing quality of the fast frozen fruit and vegetables; the present invention is characterized by a short freezing time, excellent initial shape maintenance and low operational cost.

The invention discloses a frozen fillet processing method, belonging to the fields of frozen aquatic products and aquatic product processing, which can be popularized and applied to the freezing process of other foods. In the method of the invention, protective agent is added into boned skinless fillets by injecting, ultrasonic immersing or a combined manner of injecting and ultrasonic immersing for processing the fillets; the fillet quick freezing is realized by adopting the synergistic effect of indirectly contacted alcohol freezing solution immersing and ultrasound freezing; and the fillets are frozen and stored at below 18 DEG C. The protective agent is an aqueous solution containing sodium lactate, trehalose, unfrozen protein, Nisin and salt; the protein denaturation of the frozen fillets processed by the protective agent is reduced, the retention performance is improved, the nutritional value, flavor and mouthfeel can be maintained to the largest extent, the freezing time is short, and the production efficiency is high.

The invention provides a vacuum spray-freezing granulation device and a method thereof. The device of the invention is characterized in that the device comprises a container; multiple atomizing nozzles used for atomizing and dispersing a liquid to be freeze-dried into liquid drops are arranged inside the container; and the container is connected to a vacuum system used for forming a vacuum environment in the container to make part components in the liquid drops to be vaporized and absorb heat in the vacuum environment so as to further cool and freeze the liquid drops to form granules. The method of the invention is completely different from a traditional freeze-drying granulation technology. By vacuum-pumping to freeze atomized liquid drops into granules, freezing rate of the liquid to be freeze-dried is greatly raised. According to the vacuum spray-freezing granulation device, a refrigerant nozzle is not arranged therein, a liquid nitrogen low-temperature zone is not arranged in the device, and a refrigerant is completely not used to contact with a material during the quick-freezing process so as to completely eradicate the risk that the material is polluted. Therefore, sterility of the freeze-drying process is raised, production energy consumption is reduced, and the environment will not be polluted.

The invention discloses a method for increasing the freezing speed and the quality of ice creams through double-point variable-intensity ultrasonic waves. A preparation process of the ice creams comprises the steps of raw material mixing, pasteurization, homogenizing, ageing, stirring, congelation, filling forming and hardening, wherein in the congelation stage of the ice creams, the variable-intensity ultrasonic waves are adopted for processing the ice creams; more specifically, in the nucleus forming stage, the ultrasonic wave with the intensity of 0.2-0.6W / cm<2> is used and in the crystal nucleus growth stage, the ultrasonic wave with the intensity of 0.5-0.9W / cm<2> is used. The method disclosed by the invention has the advantages that the freezing speed of the ice creams is increased; the taste and the quality of the ice creams are improved; the influence of temperature fluctuation to the ice crystal form in transportation and storage processes is reduced.

The invention provides a method for increasing the food blast freezing rate, which is characterized in that a freezing mode of a high-speed cold airflow impact type is adopted; after cooling airflow is accelerated by an air distribution plate, a part of the cooling airflow is directly jetted on the surface of foods by adopting a special design of air passages and the other part of cooling airflow goes through the two sides of a plenum box and reaches the space at the side of a conveying mesh belt to blow towards the lower surface of foods, thereby realizing simultaneous blast freezing on the upper and lower surface of foods and greatly increasing the heat transfer coefficient of the food surface. The method of the invention has the major advantages of increasing the freezing rate and freezing quality of foods, decreasing drying loss, saving energy, reducing cost and being especially applicable to the freezing of thin and flat products or blocky products of small size.

The invention relates to a novel method for improving fruit and vegetable unfreezing quality. According to the invention, ultrasonic waves are adopted for assisting in freezing in the quick freezing process of quick-frozen fruits and vegetables. The method comprises the steps of selecting, cleaning, cutting, bleaching and heating for inactivation of enzyme, cooling, freezing, freezing with the assistance of the ultrasonic waves, and packing fruits and vegetables as raw materials. According to the invention, the technology of treatment with the combination of the ultrasonic waves is adopted in the fruit and vegetable immersing and freezing process, thus the fruit and vegetable unfreezing quality is improved; and the novel method has the characteristics of shortening of freezing time, good keeping of initial shape, low operation cost and the like.

The invention discloses a freezing carrier device for vitrifying embryo and ovum in auxiliary procreation technology, which consists of a small cirque, a sliding groove, a supporting structure of the small cirque, a handle, an outer tube, a protective cap and a marking plug. The freezing carrier device for vitrifying the embryo and the ovum in the auxiliary procreation technology can improve the freezing speed of the embryo and the ovum and the defreezing and recovery survival rate of the embryo and the ovum, and reduce the lost of the embryo and the ovum caused by collision and the error and frostbite of operators.

The invention relates to the field of ice storage, in particular to an ice-storage air conditioner and an ice-storage method. Ice making and ice stripping are carried out in a circulation manner, and therefore energy efficiency and the icing rate of a system can be improved. The defects that in the prior art, a coil pipe is adopted to heat exchange, along with increasing of the thickness of an ice layer, the heat transfer resistance is increased, and consequently, the system energy efficiency is low, and the icing rate is small are overcome. The ice-storage air conditioner comprises an ice-storage barrel and a heat exchanger; the heat exchanger is placed in the ice-storage barrel, and comprises a shell and a refrigerant runner arranged in the shell; the shell comprises a heat exchange face and a non-heat-exchange face; the face opposite to the bottom of the ice-storage barrel is the non-heat-exchange face; when refrigerants subject to throttling down and decompression flow through the refrigerant runner forwards, water in contact with the heat exchange face is cooled and iced; when the refrigerants flow through the refrigerant runner in a reverse manner, ice in contact with the heat exchange face is partly molten, and the ice is separated from the heat exchange face upwards under the buoyancy effect.

The invention relates to the technical field of frozen foods, in particular to a freezing method of club mackerel and amberfish slices for reducing fish freezing degeneration and nutrient loss, maintaining original fish texture and maintaining a fish flavor. The method comprises the following steps: pretreating club mackerel and amberfish to obtain club mackerel slices and amberfish slices; performing pre-cooling; immersing the slices in a cryoprotectant; and taking out, draining, folding and packaging the slices, immersing the slices in an ultrasonic freezing device containing a chilling liquid for quick freezing, and performing freezing storage at a temperature of -18 DEG C. The method can significantly improve the quality improvement of the fish slices, and can significantly reduce thethawing loss rate of the product, improve the tenderness of the product and greatly reduce the juice loss rate after the frozen fish slices are thawed; the treatment for different ice crystal growth micro-environments of different fish parts is more uniform, and the method significantly increases the water holding capacity of the fish slices, and prevents oxidation and deterioration of fatty acidsin the fishes; and the loss of nutrients and flavor is low after thawing, a delicious taste is maintained, and the method has the characteristics of low energy consumption, high freezing rate and short processing cycle.

The invention relates to an ice maker with a carrier gas device, which comprises a machine shell, an evaporator, a freezing base plate and a carrier gas device, wherein the evaporator is connected to an ice making system and provided with a base frame; the base frame is provided with 1 to 5 freezing chambers used for making ice, and the number of the freezing chambers can be increased if necessary; the freezing base plate is arranged adjacent to the evaporator; and the carrier gas device comprises an air pump and gas pipelines and is used for inputting gas to the freezing chambers to make water in the freezing chambers generate disturbance so as to reduce under-cooling degree needed by making ice, accelerate the icing rate and improve the ice making efficiency of the whole ice maker. The ice maker is mainly applicable to occasions where water needs to be separated from a solution in a freezing mode. The application fields comprise ice making, wastewater treatment, food concentration, biological purification and the like.

The invention relates to an actinidia polygama effervescing agent and a preparation method and application thereof. The preparation method comprises the following steps: mixing the following components in parts by mass: 3-5 parts of an extracted active polysaccharide mixture, 24-30 parts of sodium bicarbonate, 15-20 parts of citric acid, 1-3 parts of an adhesive, 10-14 parts of xylitol, 4-6 parts of freeze-dried powder of filtrate obtained after actinidia polygama polysaccharide extraction and 2-5 parts of sodium alga acid, preparing a soft material, granulating, drying, pelletizing, and adding 30-50 parts of a juice clathrate compound, thereby obtaining the effervescing granules. According to the method, the process is simple, the active ingredients of the product are clear, the natural VC retention rate is over 70 percent, a xylitol formula system is adopted, and the effervescing agent is good in taste and is suitable for diabetes mellitus patients to take. The experiment proves that the actinidia polygama active polysaccharides and effervescing granules have a certain treatment effects on type II diabetes mellitus; and moreover, the effervescing agent can be widely applied to antioxidant, anti-fatigue and blood sugar-reducing foods and / or health products.

The invention provides a freezing process for fishes. The process comprises the following steps that the to-be-frozen fishes are put in flow-state ice at 0 DEG C to be pre-frozen for 1-2 hours, then quickly frozen at low temperature and subjected to cold preservation after being quickly frozen. By means of the method, the fishes can be actually cryopreserved for a long time (6-12 months), and thefood quality can be kept. The process can be actually applied to the cryopreservation of the fishes, the pre-freezing and quick-freezing techniques have small damage to the cells of the fishes, and flavor components and nutritional characteristics of the fishes can be preserved to a great extent. The process has actual application prospects for the cryopreservation of the fishes.

The invention discloses a fish flesh fragrance-locking, taste-controlling, and flavor-improving method, which comprises following steps: fish preprocessing, pulse type breathing rolling and fish fleshsurface coating-fixing, fish packing, freezing, and storing. In the pulse type breathing rolling and fish flesh surface coating-fixing, vacuum rolling is adopted, carrageenan and potassium chloride gel carry out reactions, trehalose and sodium polyphosphate are used to resist the freeze denaturation of proteins; and perilla, black tea, and ginger powder are used to carry out pickling to enhance the fragrance and remove the fishy smell. The flavor and elasticity of fish flesh are largely improved by the steps mentioned above, the quality of fish flesh is guaranteed, at the same time, the shelflife is prolonged, the needs of consumers are better satisfied, the operation is simple, the fish flesh quality is high, and the taste is good.

The invention discloses a liquid food freezing method. The method includes the following steps that (1) an initial freezing point of liquid food to be frozen is tested; (2) the liquid food circulates through an ultra-micron bubble generator, circulation stops when the bubble rate in the liquid food is 82%-90%, and the grain size of bubbles in the liquid food is 300-800 nm; (3) the liquid food full of the bubbles is introduced into an ultrasonic processor provided with a heat exchanger, the temperature of the heat exchanger is maintained between -20 DEG C to 22 DEG C through a refrigerating system, and the temperature of the liquid food is recorded; when the temperature is lowered to the temperature 0-1 DEG C below the initial freezing point, and low-intensity ultrasonic waves are started; when the temperature is lowered again to the temperature 0-1 DEG C below the initial freezing point, low-intensity ultrasonic processing stops, and high-intensity ultrasonic waves are started till the liquid food is cooled to -18 DEG C. By means of the method, the supercooling degree of the liquid food is reduced, heat transfer speed is increased, and accordingly freezing time is shortened.

The invention relates to the technical field of medical instruments, in particular to a freezing carrier rod. The device comprises a carrying rod and a sleeve, wherein the carrying rod comprises a handle and a glass slide arranged at the front end of the handle, and a latticed carrying area is formed in the glass slide. One end of the sleeve is open and the other end is closed, and the open end ofthe sleeve sleeves the front end of the handle. The latticed bearing area is arranged on the slide, so that when gametes or embryo droplets drop in the bearing area, the gametes / embryos can be stablyadsorbed on the bearing area; therefore, the adsorption performance of the slide is improved, the gametes / embryos droplets can be well fixed during freezing, and the risk that the gametes / embryos droplets drop is avoided; the grid structure can enable the embryo to be in full contact with liquid nitrogen, so that the embryo has a relatively high freezing rate; during thawing, the grid structure can reduce the contact area between gametes / embryos and the surface of the slide, is beneficial to falling of the gametes / embryos, can enable the embryos to be in full contact with thawing liquid, andhas a higher thawing rate.

The invention discloses a full-automatic multi-step freezing instrument and belongs to the field of biotechnology. The full-automatic multi-step freezing instrument comprises a box body, a box cover and a power device, wherein the interior of the box body is of a cavity lidless structure; an ejection inclined block is arranged at the bottom of the box body; a main rod guide hole and a bracket are arranged on the box cover; the power device and a temperature control device are mounted on the freezing instrument. In order to solve the problems that all samples in a freezing room are only frozen by the same freezing steps in the process of freezing and preserving device cells, either the device is imported or the manual operation is required, the device is high in subjectivity, low in accuracy, high in labor cost, complex in device container structure, the samples are inconveniently taken, the instrument is inconveniently cleaned, and the next test can be carried out by taking the samples after the test is completed, the invention provides a cell freezing device which has the advantages that the freezing rate reaches -70 DEG C per minute or is even greater than -70 DEG C per minute; the same batch of samples in the freezing room has a plurality of freezing rates; the cell freezing device is fully-automatic, can be automatically developed and produced, and is low in cost and simple in container structure; the samples can be conveniently taken out; the instrument can be conveniently cleaned; the samples can be uniformly taken out after a plurality of tests.

The invention relates to a fecal microbiota collection, cryopreservation and unfreezing method of a fecal microbiota transplantation technology. The method comprises the following steps: (1) preparingfecal microbiota; (2) carrying out vitrification freezing on the fecal microbiota prepared in the step (1) to obtain cryopreserved fecal microbiota; and (3) unfreezing and recovering the cryopreserved fecal microbiota obtained in the step (2). According to the invention, a vitrification freezing technology is adopted, so that the freezing rate (greater than 20000 DEG C / min) is greatly increased,cells rapidly form a 'glassy state' in a rapid cooling process, ice crystals are prevented from being formed inside and outside the cells, excessive damage to florae in the fecal microbiota is avoided, and an antifreezing protein is added into a cryoprotectant, so that the cytotoxicity of the cryoprotectant is avoided; and the survival rate of the flora in the unfrozen fecal microbiota liquid is increased to 90% or above.

The invention discloses an ice cream production method and an ice cream machine. After entering the ice cream machine from a feeding pipe, ice cream is congealed through a refrigerant; the ice cream is treated orthogonally by two different groups of ultrasonic waves, namely the ice cream starts to be nucleated for 3 minutes when the material temperature is negative 1 DEG C-negative 3 DEG C along with the ultrasonic action intensity being 0.8-1 W / cm<2> and the total power being 230 W; and the ice cream starts to perform phase transition when the material temperature is negative 3 DEG C-negative6 DEG C along with the ultrasonic action intensity being 1-1.2W / cm<2>, the total power being 250W and the ultrasonic treatment time being 12 minutes. Air is introduced into the freezing cavity through an air compressor and is mixed with raw materials of ice cream, orthogonal double-frequency ultrasonic wave can assist congelation, so that the cavitation effect is remarkable, the ice cream congelation efficiency is remarkably improved, the formed ice crystals and bubbles are smaller but distributed more uniform, a secondary sterilization effect is formed, and the taste and quality of the ice cream are better.

The invention discloses a serialized direct-evaporation-type high-efficient multi-temperature ice storing tank. The high-efficient multi-temperature ice storing tank does not use the ethylene glycol as the heat-transfer medium, and is capable of directly conveying the high-temperature and high-pressure organic refrigerant liquid into an evaporator for evaporating and refrigerating after throttling, absorbing the sensible heat and latent heat of the water in the tank, making ice and cooling. The serialized direct-evaporation-type high-efficient multi-temperature ice storing tank is consist of the multi-temperature ice storing tank, the evaporator, a circulation water pump, an ice nucleus generator, a water flow distributor, a splitter plate, a chilled water region, a belt-type temperature sensor, a liquid level meter, an electric proportional-integral regulating valve and the like. The serialized direct-evaporation-type high-efficient multi-temperature ice storing tank is capable of providing the chilled water with different temperatures which is used for low-temperature dehumidification and indoor cooling. The advanced technologies, such as circulation water pump, the ice nucleus generator, and the water flow distributor, are used for improving the icing rate and the icing speed, the ice storing amount is large, the cost is low and the application is extensive, various air condition ice storing tanks can be replaced by the serialized direct-evaporation-type high-efficient multi-temperature ice storing tank. The serialized direct-evaporation-type high-efficient multi-temperature ice storing tank is one of the main devices of the patent 'serialized direct-evaporation-type ice-water cooling double-cold-source air condition system' (patent number 201410359231.1).

The invention relates to a slot nozzle for an instant freezer. The slot nozzle for the instant freezer comprises a plurality of V-shaped flow guide grooves which are uniformly arranged in parallel along the moving direction of a frozen product conveying plate belt and slot nozzle bodies communicated with the lower end of the V-shaped flow guide grooves; each V-shaped guide groove comprises two strip-shaped plates which are arranged in an inclined manner, the cross section of the V-shaped flow guide groove is in a rectangular shape, the longitudinal section of the V-shaped flow guide groove inthe width direction is in an inverted trapezoid shape, and the upper portions of every two adjacent V-shaped flow guide grooves are connected through a flat plate; each slot nozzle body comprises twostrip-shaped plates which are oppositely arranged in parallel, and the upper ends of the two strip-shaped plates of each slot nozzle body are connected with the lower ends of the two strip-shaped plates of the corresponding V-shaped flow guide groove respectively; the length of each slot nozzle is 1000-2000 mm, the height of each V-shaped flow guide groove (1) is 40-90 mm, and the opening angle of each V-shaped flow guide groove ranges from 0 degree to 30 degrees; and the height of each slot nozzle (2) is 2-8 mm, and the height of each slot nozzle (2) is 0-40 mm. According to the slot nozzlefor the instant freezer, the cooling rate of the frozen product can be effectively increased, and the quality of the frozen product is improved.

The invention discloses a pore plate of an instant freezer. The pore plate comprises a first lateral-blowing pore plate board, a positive blowing pore plate board, a second lateral-blowing pore plate board and pore plate openings. The pore plate of the instant freezer is characterized in that the plane of the pore plate is an un-straight plane; and an included angle Theta is formed between the first lateral-blowing pore plate board and the positive blowing pore plate board. The pore plate can effectively strengthen convection heat exchange of the side surface of frozen food to reduce food freezing time, so that the single-direction impact problem of a conventional flat and straight pore plate is improved better, and therefore, a new idea is provided for improving freezing velocity of the instant freezer.

The embodiment of the invention provides an ice core preparation device and method. The ice core preparation device comprises a first ice making module which is a shell and is used for forming an outer mold for ice core preparation, and a second ice making module which is arranged in the first ice making module and is used for forming an inner mold for ice core preparation, the first ice making module is connected with the second ice making module, an ice core preparation water trough is formed between the first ice making module and the second ice making module, and the ice core preparation water trough is used for containing ice making raw materials. A freezing module is arranged in the ice core preparation water trough, the freezing module is fixed to the inner wall of the first ice making module, and freezing liquid is fed into the freezing module. According to the ice core preparation device and method, by means of the freezing module arranged in the ice core preparation water trough, the contact area of the freezing liquid and the ice making raw materials can be increased, the freezing rate of the ice making raw materials is increased, and the ice making efficiency is improved.

The invention discloses a V-shaped pore plate for an instant freezer. The V-shaped pore plate comprises first side air blowing pore plate surfaces, second side air blowing pore plate surfaces and pore plate holes, and is characterized in that the plane of the pore plate is a non-flat plane; an included angle theta exists between each of first side air blowing pore plate surfaces and each of second side air blowing pore plate surfaces. The V-shaped pore plate for the instant freezer can effectively increase the convection heat exchange coefficient of the side surface of quick-frozen food and shorten the freezing time of the food; and a new idea is supplied to research on increase of the freezing rate of the instant freezer.

The invention discloses a novel pore plate of an air-blowing type instant freezer. The novel pore plate comprises a first pore plate arc surface, a second pore plate arc surface and a pore plate opening. The novel pore plate is characterized in that the plane of the pore plate is a non-straight plane; and the pore plate of the instant freezer is formed by alternatively connecting the pore plate arc surfaces and the plate surface of a straight pore plate. The novel pore plate effectively increases a convection coefficient between the side surface of instantly-frozen food and cold air, reduces freezing time of food, improves the problem that a conventional flat hole plate impacts in single direction better, and provides a novel idea for improving freezing efficiency of the instant freezer.

The invention relates to the technical field of food quick freezing, and discloses a permanent magnetic field-assisted freezing-based instant freezer. The instant freezer comprises a quick-freezing house, a permanent magnet generating device, wherein the quick-freezing house is provided with a quick freezing mechanism for quickly freezing food; and the permanent magnet generating device is used for generating a constant or variable permanent magnetic field, and the permanent magnetic field is used for being distributed on the food and is used for being static or moving relative to the food. On the basis of saving energy, the quick-freezing effect on the food is ensured; and the defects that in cognition of food quick-freezing by existing technicians, a magnetic field can only be applied through an electrified coil when the food is about to be subjected to phase change, the radiation range of a permanent magnetic field generated by an existing permanent magnet is relatively small, and the permanent magnetic field is difficult to cover the food well are overcome.

A corrugated pore plate for an instant freezer comprises a first pore plate cambered face, a second pore plate cambered face and pore plate open pores. The corrugated pore plate for the instant freezer is characterized in that the pore plate plane is a non-straight plane, and the corrugated pore plate is formed in a manner that cambered faces with the same radius are sequentially tangent externally. The corrugated pore plate can effectively increase the heat exchanging coefficient of the side face of food to be frozen, the freezing time of the food to be frozen is shortened, the single-direction impact problem of a traditional straight pore plate is solved relatively well, and a new thought is provided for a study on increasing the freezing rate of a blast instant freezer.

An elongated funnel-shaped jet flow nozzle structure comprises elongated conical diversion grooves, elongated jet flow nozzles and a conveying plate strip. The elongated funnel-shaped jet flow nozzlestructure is characterized in that thickness of the elongated conical diversion grooves (1), the elongated jet flow nozzles (2) and the conveying plate strip (3) is 1-5mm, each elongated conical diversion groove (1) is in the shape of a hollow inverted elongated oval frustum with an upper-end opening and a lower-end opening, the upper-end opening of each diversion groove is connected with an elongated oval open hole while the lower-end opening of the same is connected with an inlet of the corresponding nozzle, and each nozzle is in the shape of a hollow elongated oval cylinder. The elongated funnel-shaped jet flow nozzle structure can effectively improve heat exchange intensity of a freezing area, improve freezing efficiency of an instant freezer and effectively improve the defect that conventional nozzle structures cannot balance high freezing efficiency and heat exchange uniformity.

The invention belongs to the technical field of food material freezing, and particularly relates to a quick freezing device, a control method, a control device, electronic equipment and a storage medium. According to the application, the flexible film structure is filled with the coolant, so that the flexible film structure can fully wrap the food materials, the temperature of the food materials is uniformly distributed, the freezing rate is accelerated, and the food materials can be better preserved. The quick-freezing device comprises a pre-cooling chamber, a quick-freezing chamber, a flexible membrane structure, a coolant and a circulating water pump, the cold storage agent is stored in the pre-cooling chamber, and the pre-cooling chamber is used for pre-cooling the cold storage agent; the flexible film structure is installed in the quick-freezing chamber and used for containing a cold storage agent so that the temperature borne by food materials can be evenly distributed; one end of the circulating water pump is communicated with the pre-cooling chamber, and the other end of the circulating water pump is communicated with the flexible membrane structure and used for conveying a coolant.

The invention provides a method for increasing the food blast freezing rate, which is characterized in that a freezing mode of a high-speed cold airflow impact type is adopted; after cooling airflow is accelerated by an air distribution plate, a part of the cooling airflow is directly jetted on the surface of foods by adopting a special design of air passages and the other part of cooling airflow goes through the two sides of a plenum box and reaches the space at the side of a conveying mesh belt to blow towards the lower surface of foods, thereby realizing simultaneous blast freezing on the upper and lower surface of foods and greatly increasing the heat transfer coefficient of the food surface. The method of the invention has the major advantages of increasing the freezing rate and freezing quality of foods, decreasing drying loss, saving energy, reducing cost and being especially applicable to the freezing of thin and flat products or blocky products of small size.