阅读说明：本技术 一种冷冻食品的速冻系统及用于该系统的冷冻液制备方法 (Quick-freezing system for frozen food and preparation method of refrigerating fluid for system ) 是由 李晓燕 丁志卿 陈杰 樊博玮 李立 闫淑晴 杨大恒 于 2021-08-23 设计创作，主要内容包括：一种冷冻食品的速冻系统及用于该系统的冷冻液制备方法,涉及食品冷冻保鲜技术领域。为了解决现有速冻装置的冷冻速率慢、解冻后食品中营养物质流失鲜度下降、冷冻不均匀、冷冻液在低温环境时粘度大、冷冻后部分冷冻液残留在食品表面影响食品风味和质量以及不能循环使用的问题。本发明包括速冻制冷机组和末端速冻装置；速冻制冷机组为末端速冻装置提供低温冷冻液,末端速冻装置将冷冻液的冷量与食品的热量进行换热,末端速冻装置内设置射流喷嘴,加剧了冷冻槽内部液体的扰动,使冷冻液温度更均匀；速冻系统采用的是新制备的纳米复合冷冻液,确保食品中的精细冰晶结构,保留食品原营养成分,不影响食品风味和口感。本发明主要用于食品的快速冷冻。(A quick-freezing system for frozen food and a preparation method of refrigerating fluid for the system relate to the technical field of food freezing and fresh-keeping. The quick-freezing device aims to solve the problems that the freezing speed of the existing quick-freezing device is slow, the loss freshness of nutrient substances in food after thawing is reduced, freezing is not uniform, the viscosity of freezing liquid in a low-temperature environment is high, partial freezing liquid remains on the surface of the food after freezing, the flavor and the quality of the food are influenced, and the food cannot be recycled. The invention comprises a quick-freezing refrigerating unit and a tail end quick-freezing device; the quick-freezing refrigerating unit provides low-temperature refrigerating fluid for the tail-end quick-freezing device, the tail-end quick-freezing device exchanges heat between the cold energy of the refrigerating fluid and the heat of food, and a jet nozzle is arranged in the tail-end quick-freezing device, so that the disturbance of the liquid in the freezing tank is intensified, and the temperature of the refrigerating fluid is more uniform; the quick-freezing system adopts the newly prepared nano composite freezing liquid, ensures the fine ice crystal structure in the food, retains the original nutrient components of the food, and does not influence the flavor and taste of the food. The invention is mainly used for quick freezing of food.)

1. A quick-freeze system of frozen food which characterized in that: the system comprises a quick-freezing refrigerating unit (2) and a tail end quick-freezing device; the quick-freezing refrigerating unit (2) provides low-temperature refrigerating fluid for the tail-end quick-freezing device, the tail-end quick-freezing device exchanges heat between the cold energy of the low-temperature refrigerating fluid and the heat of food, and the low-temperature refrigerating fluid is pumped into the quick-freezing refrigerating unit (2) again;

the tail end quick-freezing device comprises a freezing tank (1), a storage rack (3), a liquid separating plate (4), a support frame (5), a pressurizing circulating pump (6), a vortex shedding flowmeter (7), a master control electric box (8), a plurality of low-temperature stop valves (9), a group of bottom jet nozzles (10), two groups of side wall jet nozzles (11), a side wall liquid supply pipe (12), a side wall liquid return pipe (13), a bottom jet liquid supply pipe (14), a first side wall jet liquid supply pipe (15), a second side wall jet liquid supply pipe (17) and a freezing tank main pipeline (16);

the bottom of the freezing tank (1) is provided with a support frame (5), the shelf (3) is arranged in the tank body of the freezing tank (1), the middle positions of the two opposite side walls of the freezing tank (1) are respectively provided with a group of side wall jet nozzles (11), the bottom of the freezing tank (1) is provided with a liquid separation plate (4), and the liquid separation plate (4) is provided with a group of bottom jet nozzles (10);

a liquid outlet of a liquid outlet pipe of the quick-freezing refrigerating unit (2) is connected with a liquid inlet of a freezing groove main pipeline (16) on the freezing groove (1), four branch pipelines are arranged on the freezing groove main pipeline (16), a side wall liquid supply pipe (12), a first side wall jet liquid supply pipe (15), a bottom jet liquid supply pipe (14) and a second side wall jet liquid supply pipe (17) are sequentially arranged along the flowing direction of low-temperature freezing liquid, and the side wall liquid supply pipe (12) is connected with the liquid inlet of the freezing groove (1); the first side wall jet liquid supply pipe (15) is connected with one group of side wall jet nozzles (11), the bottom jet liquid supply pipe (14) is connected with the bottom jet nozzle (10), and the second side wall jet liquid supply pipe (17) is connected with the other group of side wall jet nozzles (11); the four branch pipelines are respectively provided with a low-temperature stop valve (9);

the main pipeline (16) of the freezing tank is also sequentially provided with a low-temperature stop valve (9), a booster circulating pump (6) and a vortex shedding flowmeter (7) along the flowing direction of low-temperature freezing liquid, and the main control electronic box (8) is used for controlling the start and stop of the booster circulating pump (6) and the vortex shedding flowmeter (7);

a liquid inlet of the side wall liquid return pipe (13) is connected with a liquid outlet of the freezing tank (1), and a liquid outlet of the side wall liquid return pipe (13) is connected with a liquid inlet of the quick-freezing refrigerating unit (2);

the quick-freezing refrigerating unit (2) comprises a compressor (211), an oil separator (212), a condenser (213), a dry filter (214), an economizer (215), a thermostatic expansion valve (216), a plate heat exchanger (217) and a gas-liquid separator (218);

the liquid outlet of a liquid inlet pipe of the quick-freezing refrigerating unit (2) is connected with the liquid inlet of a plate-type heat exchanger (217), the liquid outlet of the plate-type heat exchanger (217) is connected with the liquid inlet of a gas-liquid separator (218) through a pipeline, the liquid outlet of the gas-liquid separator (218) is connected with the liquid inlet of a compressor (211) through a pipeline, the gas outlet of the compressor (211) is connected with the gas inlet of an oil separator (212) through a pipeline, the gas outlet of the oil separator (212) is connected with the gas inlet of a condenser (213) through a pipeline, the liquid outlet of the condenser (213) is connected with the liquid inlet of a drying filter (214) through a pipeline, the liquid outlet of the drying filter (214) is connected with the liquid inlet of an economizer (215) through a pipeline, the liquid outlet of the economizer (215) is connected with the liquid inlet of the plate-type heat exchanger (217) through a pipeline, and the pipeline between the economizer (215) and the plate-type heat exchanger (217) is provided with a thermal expansion valve (216), the gas outlet of the economizer (215) is connected with the gas inlet of the compressor (211) through a pipeline.

2. The quick-freezing system for frozen food as claimed in claim 1, wherein: the electric push rod lifting device is characterized by further comprising an electric push rod (18), an electric push rod motor (19) and an electric push rod control box (20), wherein the electric push rod motor (19) is used for driving the electric push rod (18) to lift, and the electric push rod control box (20) is used for controlling the electric push rod motor (19) to open and close;

the freezing groove (1) comprises a freezing groove body and a cover plate (1-1), the top end of the storage rack (3) is fixedly connected with the lower surface of the cover plate (1-1) of the freezing groove (1), and the electric push rod (18) is fixedly connected with the outer surface of the cover plate (1-1) of the freezing groove (1).

3. The quick-freezing system for frozen food as claimed in claim 2, wherein: the aperture range of the side wall jet nozzle (11) and the bottom jet nozzle (10) is 10 mm-19 mm.

4. A quick-freezing system for frozen food as claimed in claim 3, wherein: the side wall jet nozzle (11) and the side wall of the freezing tank (1) can be adjusted in a plurality of angle rotation modes.

5. A refrigerating fluid preparation method for the quick-freezing system of frozen foods as set forth in claim 4, characterized in that: the method comprises the following steps:

step one, selecting two or more of food-grade ethanol, sodium chloride, propylene glycol, calcium chloride, magnesium sulfate, potassium chloride, glycerol, betaine, antifreeze protein and water to be mixed according to a certain proportion to obtain a mixed solution;

step two, selecting one or more of wheat starch, corn starch, straw powder, cottonseed hull powder, corn cob powder or bagasse for mixing, then filtering after pressure hydrogenation under the catalysis of nickel, then adding edible hypertonic yeast with the concentration of more than 300g/L for enzymolysis and fermentation to obtain fermented liquor, wherein the fermentation time is 30-60 min;

step three, heating, sterilizing and filtering the fermented mash obtained in the step two, purifying by ion exchange resin, activated carbon and ultrafiltration, crystallizing, washing and drying to obtain fermented crystals;

and step four, adding the fermentation crystals obtained in the step three into the mixed liquid obtained in the step one to form low-temperature refrigerating liquid.

6. The method for preparing refrigerating fluid according to claim 5, wherein: and (3) adding nano particles into the low-temperature refrigerating fluid obtained in the fourth step to obtain the nano composite refrigerating fluid.

7. The method for preparing refrigerating fluid according to claim 6, wherein: the nano composite refrigerating fluid is prepared by the following two steps:

step five, adding the nano particles with different concentrations into the low-temperature refrigerating fluid obtained in the step four to form nano particle refrigerating fluid base fluid;

step six, adding different active agents or dispersing agents into the nano particle refrigerating fluid base fluid obtained in the step five according to the concentration of the nano particles to obtain a mixed solution; and placing the mixed solution in a big beaker, sealing the big beaker by using a preservative film, placing the big beaker in a constant-temperature magnetic stirrer at 18 ℃ for stirring for 20-30 min, then placing the big beaker in an ultrasonic oscillator for oscillation for 50min, taking out the beaker after ultrasonic oscillation and standing for 30min to obtain the nano composite refrigerating fluid.

8. The method for preparing a refrigerating fluid according to claim 7, wherein: in the sixth step, the dosage ratio of the nano particles to the active agent or the dispersing agent is 1:1, and 0.5g of the active agent or the dispersing agent is introduced into the nano particle freezing liquid base liquid obtained in the fifth step at the speed of 0.4-0.8 mL/h.

9. The method for preparing refrigerating fluid according to claim 8, wherein: the nano particles are nano zinc oxide.

10. The method for preparing refrigerating fluid according to any one of claims 5 to 9, wherein: the edible hypertonic yeast is selected from the group consisting of Plectosporium, Candida lipolytica and Trichosporon pseudomyces.

Technical Field

The invention relates to the technical field of food freezing and fresh-keeping, in particular to a quick-freezing system for frozen food and a refrigerating fluid preparation method for the system.

Background

With the development of global economy and the improvement of the living standard of people, the demand of people for frozen foods is higher and higher, so that the quality of the frozen foods becomes a problem which is concerned by people. Many studies have shown that the freezing speed is a key factor for maintaining the quality of frozen food, the freezing time of slow freezing is long, the band velocity through the maximum ice crystal generation is slow, the generated ice crystals are large in volume, small in quantity and irregular in distribution, and the damage to the cell tissues of the food is large, thereby affecting the quality of the food. The quick freezing time is short, countless needle-shaped small ice crystals are generated and uniformly distributed, the damage to the cell tissues of the food is small, and the flavor and the mouthfeel of the food are basically not influenced.

The demand of people for quick-frozen foods also continuously promotes the development of food quick-freezing devices. Most of the existing quick-freezing devices adopt air blowing type quick freezing, cold air is used as a freezing medium, gas is subjected to convection heat transfer to cool and freeze food, but the devices have low convection heat transfer coefficient, high energy consumption and low freezing rate, so that the loss of water during freezing and the redistribution and arrangement of the thawed water in the food seriously affect the freshness and taste of the food and the food quality. In order to solve the problem of low freezing rate, people also provide direct contact type freezing for exchanging heat by direct contact of food and unfrozen liquid, wherein the direct contact type freezing can be divided into spray type freezing and immersion type freezing, the most common spray type equipment is a liquid nitrogen ultralow temperature quick freezing device, the liquid nitrogen quick freezing has high freezing speed and low dry consumption, but the equipment structure is complex, and the liquid nitrogen refrigerating working medium cannot be recycled when in use, so that the use cost is increased; the viscosity of the low-temperature secondary refrigerant used in the immersion freezing method is increased in a low-temperature environment, the flow lift of the pump is reduced, the delivery power is low, the power consumption of the pump is increased, partial refrigerating fluid remains on the surface of food after immersion freezing processing, the quality of the refrigerating fluid is reduced, the original flavor and taste of the food are affected, and the freshness and quality of the food are reduced. Therefore, it is necessary to design a quick freezing device which can keep fresh more and has a fast freezing speed.

Disclosure of Invention

The technical problems to be solved by the invention are as follows: the existing quick-freezing device has the problems of slow freezing speed, reduced loss and freshness of nutrient substances in food after unfreezing, uneven freezing, high viscosity of freezing liquid in a low-temperature environment, influence on the flavor and quality of the food due to partial freezing liquid remained on the surface of the food after freezing and incapability of recycling; further provides a quick-freezing system for frozen food and a refrigerating fluid preparation method for the system.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the quick-freezing system for frozen food comprises a quick-freezing refrigerating unit and a tail end quick-freezing device; the quick-freezing refrigerating unit provides low-temperature refrigerating fluid for the tail-end quick-freezing device, the tail-end quick-freezing device exchanges heat between the cold energy of the low-temperature refrigerating fluid and the heat of food, and the low-temperature refrigerating fluid is pumped into the quick-freezing refrigerating unit again;

the tail end quick-freezing device comprises a freezing tank, a storage rack, a liquid separating plate, a support frame, a pressurizing circulating pump, a vortex flowmeter, a main control electric box, a plurality of low-temperature stop valves, a group of bottom jet nozzles, two groups of side wall jet nozzles, a side wall liquid supply pipe, a side wall liquid return pipe, a bottom jet liquid supply pipe, a first side wall jet liquid supply pipe, a second side wall jet liquid supply pipe and a freezing tank main pipeline;

the bottom of the freezing tank is provided with a support frame, the shelf is arranged in the tank body of the freezing tank, a group of side wall jet nozzles are respectively arranged in the middle positions of the two opposite side walls of the freezing tank, the bottom of the freezing tank is provided with a liquid separation plate, and the liquid separation plate is provided with a group of bottom jet nozzles;

the liquid outlet of the liquid outlet pipe of the quick-freezing refrigerating unit is connected with the liquid inlet of a main freezing tank pipeline on a freezing tank, four branch pipelines are arranged on the main freezing tank pipeline, a side wall liquid supply pipe, a first side wall jet liquid supply pipe, a bottom jet liquid supply pipe and a second side wall jet liquid supply pipe are sequentially arranged along the flowing direction of low-temperature freezing liquid, and the side wall liquid supply pipe is connected with the liquid inlet of the freezing tank; the first side wall jet flow liquid supply pipe is connected with one group of side wall jet flow nozzles, the bottom jet flow liquid supply pipe is connected with the bottom jet flow nozzles, and the second side wall jet flow liquid supply pipe is connected with the other group of side wall jet flow nozzles; the four branch pipelines are respectively provided with a low-temperature stop valve; the main pipeline of the freezing tank is also sequentially provided with a low-temperature stop valve, a booster circulating pump and a vortex shedding flowmeter along the flowing direction of low-temperature refrigerating fluid, and the main control electronic box is used for controlling the start and stop of the booster circulating pump and the vortex shedding flowmeter; the liquid inlet of the side wall liquid return pipe is connected with the liquid outlet of the freezing tank, and the liquid outlet of the side wall liquid return pipe is connected with the liquid inlet of the quick-freezing refrigerating unit.

The quick-freezing refrigerating unit comprises a compressor, an oil separator, a condenser, a drying filter, an economizer, a thermal expansion valve, a plate heat exchanger and a gas-liquid separator;

the liquid outlet of quick-freeze refrigerating unit's feed liquor pipe be connected with plate heat exchanger's inlet, plate heat exchanger's liquid outlet passes through the pipeline and is connected with gas-liquid separator's inlet, gas-liquid separator's liquid outlet passes through the pipeline and is connected with the inlet of compressor, the gas outlet of compressor passes through the pipeline and is connected with oil separator's air inlet, oil separator's gas outlet passes through the pipeline and is connected with the air inlet of condenser, the liquid outlet of condenser passes through the pipeline and is connected with drier-filter's inlet, the liquid outlet of economizer passes through the pipeline and is connected with plate heat exchanger's inlet, economizer and plate heat exchanger between the pipeline on be provided with thermal expansion valve, the gas outlet of economizer passes through the pipeline and is connected with the air inlet of compressor.

The electric push rod lifting device further comprises an electric push rod, an electric push rod motor and an electric push rod control box, wherein the electric push rod motor is used for driving the electric push rod to lift, and the electric push rod control box is used for controlling the electric push rod motor to open and close;

the freezing groove include freezing groove cell body and apron, the top of supporter and the lower surface of the apron of freezing groove link firmly, electric putter and the surface of the apron of freezing groove link firmly.

Furthermore, the aperture range of the side wall jet nozzle and the bottom jet nozzle is 10-19 mm;

furthermore, the side wall jet nozzle and the side wall of the freezing groove can be adjusted in a plurality of angle rotation modes.

A method for preparing refrigerating fluid comprises the following steps:

step one, selecting two or more of food-grade ethanol, sodium chloride, propylene glycol, calcium chloride, magnesium sulfate, potassium chloride, glycerol, betaine, antifreeze protein and water to be mixed according to a certain proportion to obtain a mixed solution;

step two, selecting one or more of wheat starch, corn starch, straw powder, cottonseed hull powder, corn cob powder or bagasse for mixing, then filtering after pressure hydrogenation under the catalysis of nickel, then adding edible hypertonic yeast with the concentration of more than 300g/L for enzymolysis and fermentation to obtain fermented liquor, wherein the fermentation time is 30-60 min;

step three, heating, sterilizing and filtering the fermented mash obtained in the step two, purifying by ion exchange resin, activated carbon and ultrafiltration, crystallizing, washing and drying to obtain fermented crystals;

and step four, adding the fermentation crystals obtained in the step three into the mixed liquid obtained in the step one to form low-temperature refrigerating liquid.

Furthermore, nano particles can be added into the low-temperature refrigerating fluid obtained in the fourth step to obtain the nano composite refrigerating fluid.

Further, the nano-composite refrigerating fluid is prepared by the following two steps:

step five, adding the nano particles with different concentrations into the low-temperature refrigerating fluid obtained in the step four to form nano particle refrigerating fluid base fluid;

step six, adding different active agents or dispersing agents into the nano particle refrigerating fluid base fluid obtained in the step five according to the concentration of the nano particles to obtain a mixed solution; and placing the mixed solution in a big beaker, sealing the big beaker by using a preservative film, placing the big beaker in a constant-temperature magnetic stirrer at 18 ℃ for stirring for 20-30 min, then placing the big beaker in an ultrasonic oscillator for oscillation for 50min, taking out the beaker after ultrasonic oscillation and standing for 30min to obtain the nano composite refrigerating fluid.

Further, in the sixth step, the dosage ratio of the nano particles to the active agent or the dispersing agent is 1:1, and 0.5g of the active agent or the dispersing agent is introduced into the nano particle refrigerating liquid base liquid obtained in the fifth step at the speed of 0.4 mL/h-0.8 mL/h.

Furthermore, the nano particles are nano zinc oxide.

Further, the edible hypertonic yeast is selected from the group consisting of Plectosporium, Candida lipolytica, and Trichosporon pseudomyces.

Compared with the prior art, the invention has the following beneficial effects:

1. the low-temperature refrigerating fluid prepared by the invention is food-grade refrigerating fluid, is safe, nontoxic and non-corrosive, has higher heat conductivity coefficient, smaller viscosity and smaller flow resistance in a low-temperature environment, reduces the power consumption of a pump, has higher speed of pumping the low-temperature refrigerating fluid into a refrigerating groove, prolongs the service life of equipment, can be recycled for multiple times, reduces the replacement frequency of the low-temperature refrigerating fluid and reduces the production cost.

2. Because the low-temperature refrigerating fluid has small viscosity and small flow resistance, the refrigerating fluid can pass through a key region (the temperature can be quickly between minus 1 ℃ and minus 8 ℃) of water crystallization, and the refrigerating fluid basically does not remain on the surface of food, thereby ensuring a fine ice crystal structure in the food, having small damage to the cell tissue of the food, furthest retaining the original nutrient components of the food, and basically not influencing the flavor and the taste of the food.

3. The jet nozzles are arranged at the bottom and the side wall of the freezing tank in the quick-freezing system, so that food is sprayed and frozen from the nozzles while being soaked and frozen, the freezing speed is improved, the disturbance of liquid in the freezing tank is aggravated by the spraying of the nozzles, the temperature of low-temperature refrigerating liquid in the freezing tank is more uniform, the food and the low-temperature refrigerating liquid can be in full and uniform contact, the food is frozen more uniformly, the appearance is excellent, and the freshness and the quality are better.

4. The commodity shelf in the quick-freezing system has the advantages that the commodity shelf is vertically arranged in multiple layers and can be detached at an adjustable interval, the application range is improved, the refrigeration operation can be carried out simultaneously, the working efficiency is high, the space above the height is fully utilized, the occupied area is small, and the operation cost is reduced.

5. The quick-freezing system is provided with the electric lifting mechanism, so that the operation is easier, the automation is convenient, and the labor cost is greatly reduced.

Drawings

FIG. 1 is a right side view of the quick freeze system of the present invention;

FIG. 2 is an overall configuration diagram of the quick-freezing system of the present invention;

FIG. 3 is a system configuration diagram of a quick-freezing refrigerating unit;

FIG. 4 is a fragmentary perspective view of a sidewall jet nozzle;

FIG. 5 is a view of the structure of the shelf;

FIG. 6 is a layout view of bottom jet nozzles on a liquid distribution plate;

FIG. 7 is a graph showing the step size of the cryogenic liquid obtained in example 1;

FIG. 8 is a graph showing the step profile of the cryogenic refrigerating fluid obtained in example 2.

Detailed Description

The technical scheme of the invention is further explained by the specific embodiment with the attached drawings:

as shown in fig. 1 and 2, the quick-freezing system for frozen food comprises a quick-freezing refrigerating unit 2 and a tail end quick-freezing device; the quick-freezing refrigerating unit 2 provides low-temperature refrigerating fluid for the tail-end quick-freezing device, the tail-end quick-freezing device exchanges heat between the cold energy of the low-temperature refrigerating fluid and the heat of food, and the low-temperature refrigerating fluid is pumped into the quick-freezing refrigerating unit 2 again;

the tail end quick-freezing device comprises a freezing tank 1, a storage rack 3, a liquid separating plate 4, a support frame 5, a pressurizing circulating pump 6, a vortex shedding flowmeter 7, a main control electric box 8, a plurality of low-temperature stop valves 9, a group of bottom jet nozzles 10, two groups of side wall jet nozzles 11, a side wall liquid supply pipe 12, a side wall liquid return pipe 13, a bottom jet liquid supply pipe 14, a first side wall jet liquid supply pipe 15, a second side wall jet liquid supply pipe 17 and a freezing tank main pipeline 16;

the freezing tank 1 is of a cuboid tank type container structure with an opening on the upper surface, and comprises a freezing tank body and a cover plate 1-1, wherein panels inside and outside the freezing tank body are made of 304 stainless steel plates, and a middle heat-insulating layer is made of hard polyurethane foam to prevent cold leakage; the lower surface of the cover plate 1-1 of the freezing tank 1 is provided with an upper end bearing frame component. Supporter 3 set up in the cell body of freezing groove 1, supporter 3 be the upper and lower multilayer support body that forms by stainless steel square tube welding, the top of supporter be provided with the couple, upper end bearing frame component fixed connection on couple and the apron 1-1, every layer of support body of supporter between the interval adjustable and can dismantle, increaseed the freezing scope of supporter, can adjust according to the food quantity and the size that actually freeze, can freeze the operation to various food simultaneously like this, work efficiency is high. The bottom of the freezing tank 1 is provided with a support frame 5, and the support frame 5 is formed by welding equal angle steel and channel steel.

A group of side wall jet nozzles 11 are respectively arranged in the middle of the side walls at two opposite sides of the freezing tank 1, each group of side wall jet nozzles 11 is formed by arranging a plurality of side wall jet nozzles 11 in an array mode, and a plurality of angles between the side wall jet nozzles 11 and the side walls of the freezing tank 1 can be adjusted in a rotating mode;

the bottom of the freezing tank 1 is provided with a liquid separation plate 4, and the liquid separation plate 4 is provided with a group of bottom jet nozzles 10; each group of bottom jet nozzles 10 are vertically and uniformly distributed on the liquid separation plate 4 at the bottom of the freezing tank in a 5 multiplied by 5 array mode;

the side wall jet nozzle 11 and the bottom jet nozzle 10 are both made of 304 stainless steel, the sealing washer is made of nitrile rubber, the aperture range of the side wall jet nozzle 11 and the bottom jet nozzle 10 is 10-19 mm, and the aperture can be adjusted according to the size of frozen food.

A liquid outlet of a liquid outlet pipe of the quick-freezing refrigerating unit 2 is connected with a liquid inlet of a freezing tank main pipeline 16 on the freezing tank 1, four branch pipelines are arranged on the freezing tank main pipeline 16, a side wall liquid supply pipe 12, a first side wall jet liquid supply pipe 15, a bottom jet liquid supply pipe 14 and a second side wall jet liquid supply pipe 17 are sequentially arranged along the flowing direction of low-temperature freezing liquid, and the side wall liquid supply pipe 12 is connected with the liquid inlet of the freezing tank 1; the first side wall jet supply pipe 15 is connected with one group of side wall jet nozzles 11, the bottom jet supply pipe 14 is connected with the bottom jet nozzle 10, and the second side wall jet supply pipe 17 is connected with the other group of side wall jet nozzles 11; the four branch pipelines are respectively provided with a low-temperature stop valve 9; the main pipeline 16 of the freezing tank is also sequentially provided with a low-temperature stop valve 9, a booster circulating pump 6 and a vortex shedding flowmeter 7 along the flowing direction of low-temperature refrigerating fluid, and the main control electronic box 8 is used for controlling the start and stop of the booster circulating pump 6 and the vortex shedding flowmeter 7; the liquid inlet of the side wall liquid return pipe 13 is connected with the liquid outlet of the freezing tank 1, and the liquid outlet of the side wall liquid return pipe 13 is connected with the liquid inlet of the quick-freezing refrigerating unit 2.

First side wall efflux feed pipe 15 and second side wall efflux feed pipe 17 all include that the total collecting section of lateral wall efflux confession, lateral wall efflux feed collecting section and the sub-strand efflux confession liquid pipe section, sub-strand efflux confession liquid pipe section end-to-end connection lateral wall fluidic nozzle 11, be provided with low temperature stop valve 9 on the sub-strand efflux confession liquid pipe section, the quantity of nozzle can be opened according to how much of food quantity when freezing, freezing groove main line 16, lateral wall feed pipe 12, first side wall efflux feed pipe 15, bottom efflux feed pipe 14, second lateral wall efflux feed pipe 17, the total collecting section of lateral wall efflux confession, lateral wall efflux pipe section confession liquid pipe section collecting section and sub-strand efflux confession liquid pipe section all are stainless steel pipe.

The quick-freezing refrigerating unit 2 comprises a compressor 211, an oil separator 212, a condenser 213, a drying filter 214, an economizer 215, a thermostatic expansion valve 216, a plate heat exchanger 217 and a gas-liquid separator 218;

the liquid outlet of the liquid inlet pipe of the quick-freezing refrigerating unit 2 is connected with the liquid inlet of the plate-type heat exchanger 217, the liquid outlet of the plate-type heat exchanger 217 is connected with the liquid inlet of the gas-liquid separator 218 through a pipeline G8, the liquid outlet of the gas-liquid separator 218 is connected with the liquid inlet of the compressor 211 through a pipeline G9, the gas outlet of the compressor 211 is connected with the gas inlet of the oil separator 212 through a pipeline G1, the gas outlet of the oil separator 212 is connected with the gas inlet of the condenser 213 through a pipeline G2, the liquid outlet of the condenser 213 is connected with the liquid inlet of the drying filter 214 through a pipeline G3, the liquid outlet of the drying filter 214 is connected with the liquid inlet of the economizer 215 through a pipeline G4, the liquid outlet of the economizer 215 is connected with the liquid inlet of the plate-type heat exchanger 217 through a pipeline G5, a thermostatic expansion valve 216 is arranged on a pipeline G5 between the economizer 215 and the plate heat exchanger 217, and an air outlet of the economizer 215 is connected with an air inlet of the compressor 211 through a pipeline G7;

wherein the compressor 211 discharges the refrigerant; the condenser 213 is a V-shaped condenser, and the condenser 213 condenses the refrigerant and outputs a high-pressure refrigerant; the thermostatic expansion valve 216 expands the high-pressure refrigerant; the plate heat exchanger 217 evaporates the expanded high-pressure refrigerant to output a low-pressure refrigerant; the gas-liquid separator 218 processes a gaseous refrigerant containing a small amount of condensate; the oil separator 212 separates the lubricating oil in the gaseous refrigerant discharged from the compressor 211; the filter-drier 214 absorbs moisture and filters impurities; the economizer 215 is a heat exchanger, and the high-pressure liquid refrigerant from the condenser enters the refrigeration system of the compressor 211 for the second time. The refrigerant enters the quick-freezing refrigerating unit from the liquid inlet, and enters the tail end quick-freezing device after completing a refrigeration cycle.

The quick-freezing system for frozen food further comprises an electric push rod 18, an electric push rod motor 19 and an electric push rod electric control box 20, wherein the electric push rod motor 19 is used for driving the electric push rod 18 to lift, and the electric push rod electric control box 20 is used for controlling the electric push rod motor 19 to open and close; the electric push rod 18 is fixedly connected with the outer surface of the cover plate 1-1 of the freezing tank 1.

The quick-freezing system for frozen food comprises the following specific working processes:

firstly, when food is frozen, an electric push rod electricity control box 20 is opened, an electric push rod motor 19 is started, a cover plate 1-1 of a freezing tank and a storage rack 3 are lifted together by utilizing an electric push rod 18, the food to be frozen is horizontally placed on the storage rack 3, and then the food is lowered into the freezing tank 1 and covered with the cover plate 1-1;

secondly, starting the quick-freezing refrigerating unit, operating the quick-freezing refrigerating unit 2 for 60-90 minutes, and cooling the low-temperature refrigerating fluid to-22 ℃;

thirdly, opening the low-temperature stop valve 9 on the main pipeline 16 of the freezing tank, closing the low-temperature stop valves 9 on the first side wall jet flow liquid supply pipe 15, the bottom jet flow liquid supply pipe 14 and the second side wall jet flow liquid supply pipe 17, and injecting the low-temperature refrigerating liquid in the quick-freezing refrigerating unit 2 into the freezing tank 1;

finally, closing the low-temperature stop valve 9 on the side wall liquid supply pipe 12, opening the low-temperature stop valves 9 on the first side wall jet liquid supply pipe 15, the bottom jet liquid supply pipe 14 and the second side wall jet liquid supply pipe 17, opening the main control electric box 8, enabling the booster circulating pump 6 and the vortex shedding flowmeter 7 to work, pumping the low-temperature refrigerating fluid in the quick-freezing refrigerating unit 2 into the booster circulating pump 6, gradually increasing the flow rate, and displaying real-time data of flow by a flow meter digital display instrument on the main control electric box 8 so as to control the flow rate in the quick-freezing device; the booster circulating pump 6 boosts the pumped low-temperature refrigerating fluid, the low-temperature refrigerating fluid is pumped to the bottom jet flow liquid supply pipe 14, the first side wall jet flow liquid supply pipe 15 and the second side wall jet flow liquid supply pipe 17, the low-temperature refrigerating fluid pumped to the bottom jet flow nozzle 10 and the side wall jet flow nozzle 11 is sprayed and refrigerated to the food to be refrigerated in the shelf 3, the low-temperature refrigerating fluid and the food generate heat convection, the food is refrigerated by absorbing heat from the food, the food is continuously and circularly refrigerated by the low-temperature refrigerating fluid, and the food to be refrigerated can be completely refrigerated after about 120 minutes; pumping the frozen low-temperature refrigerating fluid back to the quick-freezing refrigerating unit 2 through the side wall fluid return pipe 13 again, opening the cover plate 1-1 by using the electric push rod 18 after the freezing process is finished, simultaneously lifting the storage rack 3, and taking out the frozen food;

the low-temperature refrigerating fluid from the refrigerating tank flows through the plate heat exchanger 217 and the pipeline G8 in sequence and enters the gas-liquid separator 218 for separation, the separated low-temperature refrigerating fluid is compressed by the compressor 211, the compressed gaseous refrigerant is discharged, and the compressed gaseous refrigerant is supplied to the oil separator 212 through the pipeline G1; the oil separator 212 separates the lubricating oil in the high-pressure gaseous refrigerant discharged from the compressor 211 to ensure the safe and efficient operation of the device; the condenser 213 cools and condenses the gaseous refrigerant supplied from the oil separator 212 through the line G2 into a high-pressure liquid refrigerant, and then sends the refrigerant to the dry filter 214 through the line G3 to absorb the moisture and solid impurities in the refrigerant liquid, and then the refrigerant enters the economizer 215 through the line G4; the high-pressure liquid refrigerant from the condenser 213 is divided into two parts after entering the economizer 215, one part is further cooled in a heat expansion mode by throttling to reduce the temperature of the other part for supercooling, the stabilized liquid refrigerant realizes the pressure drop from the condensing pressure to the evaporating pressure through a thermal expansion valve 216 through a pipeline G5, directly enters the plate heat exchanger 217 through a pipeline G5, and the refrigerated low-temperature refrigerating fluid is supplied to the refrigerating tank again; the other part of the uncooled gaseous refrigerant passes through a communication pipeline G7 between the economizer 215 and the compressor 211, reenters the compressor 211 to be compressed continuously, and enters the circulation; the gaseous refrigerant from the plate heat exchanger 217 enters the gas-liquid separator 218 through the line G8, is separated, and then reenters the compressor 211 through the line G9, and a new refrigeration cycle is started.

The preparation method of the low-temperature refrigerating fluid comprises the following steps:

step one, selecting two or more of food-grade ethanol, sodium chloride, propylene glycol, calcium chloride, magnesium sulfate, potassium chloride, glycerol, betaine, antifreeze protein and water to be mixed according to a certain proportion to obtain a mixed solution;

step two, selecting one or more of wheat starch, corn starch, straw powder, cottonseed hull powder, corn cob powder or bagasse for mixing, then filtering after pressure hydrogenation under the catalysis of nickel, then adding edible hypertonic yeast with the concentration of more than 300g/L for enzymolysis and fermentation to obtain fermented liquor, wherein the fermentation time is 30-60 min;

step three, heating, sterilizing and filtering the fermented mash obtained in the step two, purifying by ion exchange resin, activated carbon and ultrafiltration, crystallizing, washing and drying to obtain fermented crystals;

step four, adding the fermentation crystals obtained in the step three into the mixed liquid obtained in the step one to form low-temperature refrigerating liquid;

step five, adding the nano particles with different concentrations into the low-temperature refrigerating fluid obtained in the step four to form nano particle refrigerating fluid base fluid;

step six, adding different active agents or dispersing agents into the nano particle refrigerating fluid base fluid obtained in the step five according to the concentration of the nano particles to obtain a mixed solution; the dosage ratio of the nano particles to the active agent or the dispersing agent is 1:1, and 0.5g of the active agent or the dispersing agent is introduced into the nano particle refrigerating fluid base fluid obtained in the fifth step at the speed of 0.4 mL/h-0.8 mL/h;

and placing the mixed solution in a big beaker, sealing the big beaker by using a preservative film, placing the big beaker in a constant-temperature magnetic stirrer at 18 ℃ for stirring for 20-30 min, then placing the big beaker in an ultrasonic oscillator for oscillation for 50min, taking out the beaker after ultrasonic oscillation and standing for 30min to obtain the nano composite refrigerating fluid.

The edible hypertonic yeast is selected from the group consisting of Plectosporium, Candida lipolytica, Trichosporon pseudospore, and the like.

The nano particles are nano zinc oxide and the like.

Compared with the original refrigerating fluid, the low-temperature refrigerating fluid is food-grade refrigerating fluid, is safe, non-toxic and non-corrosive, can be recycled for multiple times, and has higher heat conductivity coefficient and lower viscosity at the same temperature; the size of ice crystals generated in food is related to the speed of passing through a maximum ice crystal generation area, the lower the viscosity of the low-temperature refrigerating fluid is, the lower the flow resistance of the liquid is, the lower the conveying power of a pressurizing circulating pump in the device is, the higher the speed of pumping the low-temperature refrigerating fluid into a freezing tank is, the low-temperature refrigerating fluid can quickly pass through a key area (from-1 to-8 ℃) of water crystals, and the heat of the frozen food can be conducted and absorbed through the low-temperature refrigerating fluid in a very short time, so that the ice crystal structure in the food can form numerous small needle-shaped ice crystals which are uniformly distributed, the damage to the cell tissue of the food is small, the original nutrient components of the food are reserved to the maximum extent, and the flavor and the mouthfeel of the food are not influenced basically.

Example 1:

the preparation method of the refrigerating fluid comprises the following steps:

step one, selecting ethanol, sodium chloride, calcium chloride, potassium chloride, glycerol, betaine and water, and mixing according to a certain proportion to obtain a mixed solution;

step two, selecting wheat starch, straw powder, cottonseed hull powder and bagasse, mixing, then filtering after pressure hydrogenation under the catalysis of nickel, adding aureobasidium basidiosum with the concentration of 350g/L for enzymolysis and fermentation to obtain fermented liquor, wherein the fermentation time is 30 min;

step three, heating, sterilizing and filtering the fermented mash obtained in the step two, purifying by ion exchange resin, activated carbon and ultrafiltration, crystallizing, washing and drying to obtain fermented crystals;

step four, adding the fermentation crystals obtained in the step three into the mixed liquid obtained in the step one to form low-temperature refrigerating liquid;

step five, adding nano zinc oxide with different concentrations into the low-temperature refrigerating fluid obtained in the step four to form nano particle refrigerating fluid base fluid;

step six, adding different active agents or dispersing agents into the nano particle refrigerating fluid base fluid obtained in the step five according to the concentration of the nano particles to obtain a mixed solution; the dosage ratio of the nano particles to the active agent or the dispersing agent is 1:1, and 0.5g of the active agent or the dispersing agent is introduced into the nano particle refrigerating liquid base liquid obtained in the fifth step at the speed of 0.6 mL/h; and placing the mixed solution in a big beaker, sealing the big beaker by using a preservative film, placing the big beaker in a constant-temperature magnetic stirrer at 18 ℃ for stirring for 20min, then placing the big beaker in an ultrasonic oscillator for oscillating for 50min, taking out the beaker after ultrasonic oscillation and standing for 30min to obtain the nano composite refrigerating fluid.

Aiming at the nano-composite refrigerating fluid obtained in the embodiment 1, a 2700 multi-channel data acquisition instrument is adopted to record a step curve of the low-temperature refrigerating fluid, and the specific process is as follows:

placing a thermocouple at the center of a low-temperature refrigerating fluid sample to be tested, ensuring that a temperature probe of the thermocouple is positioned in the middle of the sample to be tested, starting a test program, setting a data acquisition instrument to read temperature data every 1s in the test, enabling a steep part (namely a cooling curve) and a gentle part (namely a crystallization curve) of a curve to be seen on a step curve, enabling the projection of the intersection point of the steep part and the gentle part on a vertical coordinate of the step curve to be the freezing point of the refrigerating fluid sample, and enabling the obtained curve to be the step curve of the low-temperature refrigerating fluid sample, as shown in fig. 7, being a step curve diagram of the nano-composite refrigerating fluid obtained in the embodiment; it can be seen from FIG. 7 that the freezing point of the nanocomposite freezing fluid of the present embodiment is-37.8 ℃.

Example 2:

the preparation method of the refrigerating fluid comprises the following steps:

step one, selecting ethanol, sodium chloride, propylene glycol, calcium chloride, magnesium sulfate, antifreeze protein and water, and mixing the ethanol, the sodium chloride, the propylene glycol, the calcium chloride, the magnesium sulfate, the antifreeze protein and the water according to a certain proportion to obtain a mixed solution;

step two, selecting corn starch, cottonseed hull powder, corncob powder and bagasse for mixing, then filtering after pressure hydrogenation under the catalysis of nickel, and then adding candida lipolytica with the concentration of 400g/L for enzymolysis and fermentation to obtain fermented liquor, wherein the fermentation time is 60 min;

step three, heating, sterilizing and filtering the fermented mash obtained in the step two, purifying by ion exchange resin, activated carbon and ultrafiltration, crystallizing, washing and drying to obtain fermented crystals;

step four, adding the fermentation crystals obtained in the step three into the mixed liquid obtained in the step one to form low-temperature refrigerating liquid;

step five, adding nano zinc oxide with different concentrations into the low-temperature refrigerating fluid obtained in the step four to form nano particle refrigerating fluid base fluid;

step six, adding different active agents or dispersing agents into the nano particle refrigerating fluid base fluid obtained in the step five according to the concentration of the nano particles to obtain a mixed solution; the dosage ratio of the nano particles to the active agent or the dispersing agent is 1:1, and 0.5g of the active agent or the dispersing agent is introduced into the nano particle refrigerating liquid base liquid obtained in the fifth step at the speed of 0.7 mL/h; and placing the mixed solution in a big beaker, sealing the big beaker by using a preservative film, placing the big beaker in a constant-temperature magnetic stirrer at 18 ℃ for stirring for 30min, then placing the big beaker in an ultrasonic oscillator for oscillating for 50min, taking out the beaker after ultrasonic oscillation and standing for 30min to obtain the nano composite refrigerating fluid.

Aiming at the nano-composite refrigerating fluid obtained in the embodiment 2, a 2700 multi-channel data acquisition instrument is adopted to record a step curve of the low-temperature refrigerating fluid, a thermocouple is placed at the center of a low-temperature refrigerating fluid sample to be tested, a temperature probe of the thermocouple is ensured to be positioned in the middle of the sample to be tested, a test program is started, the data acquisition instrument is set to read temperature data every 1s during test, a steep part (namely, a cooling curve) and a gentle part (namely, a crystallization curve) of the curve can be seen on the step curve, the projection of the intersection point of the steep part and the gentle part on the vertical coordinate is the freezing point of the refrigerating fluid sample, and the obtained curve is the step curve of the low-temperature refrigerating fluid sample. FIG. 8 is a graph showing the step cooling curve of the nanocomposite freezing fluid obtained in the present example; it can be seen from FIG. 8 that the freezing point of the nanocomposite freezing fluid of this example is-62.3 ℃.

The experiment proves that the food-grade low-temperature refrigerating fluid is a transparent liquid without corrosiveness and pungent smell, the freezing point is generally-20 to-70 ℃, the viscosity can reach 2.048mPa & s at the minimum at normal temperature, the heat conductivity coefficient is higher than 0.495W/m & K, the refrigerating fluid can be recycled for multiple times, and the refrigerating fluid has the advantages of safety, no toxicity, lower freezing point, smaller viscosity and higher heat conductivity coefficient, and can be used for quickly freezing food; when the food is frozen, the viscosity of the low-temperature refrigerating fluid is low, the flow resistance of the fluid is low, the lower the conveying power of a pressurizing circulating pump in the device is, the power consumption of the pump can be reduced, and the service life of the equipment can be prolonged.