RU2777110C1 - Tunnel device for freezing water-containing foodstuffs - Google Patents

Abstract

FIELD: food products freezing.

SUBSTANCE: proposed group of inventions is intended for organizing a continuous technological process of freezing food products using tunnel-type quick-freezing equipment. The device contains a thermally insulated chamber, a chain conveying device equipped with clamping brackets, inlet and outlet conveyor belts, containers, a bath for liquid refrigerant - ethanol, a cooling system, a filtration and pumping unit, a fan unit, a control and monitoring unit and paired modules with electrode matrices, equipped with an electric field generator. The bath can be made single-channel or multi-channel. The control and monitoring unit controls the switching on of the potentials of the electrodes until the completion of the water-ice phase transition. The device provides rapid cooling of the food product to a temperature of -15°C to -20°C and the simultaneous creation of an inhomogeneous alternating electric field around the frozen product with static strength gradients. An alternating electric field is created due to the presence of paired modules with upper and lower matrices of electrodes, which are supplied with a high-voltage alternating current potential or which are grounded, respectively.

EFFECT: ensuring the prevention of the formation of ice crystals, continuous in-line freezing of food, fast and efficient heat removal from the food, long-term preservation of the organoleptic properties and physico-chemical characteristics of the product, reducing the time of freezing food compared to other freezing methods.

26 cl, 3 tbl, 13 dwg

Description

The proposed group of inventions relates to quick-freezing equipment for freezing foodstuffs and is intended for organizing a continuous technological process for freezing foodstuffs without crystallization of water in frozen products during the water-ice phase transition.

BACKGROUND OF THE INVENTION

For many decades, efforts to optimize the freezing of objects of organic and inorganic origin have been aimed at reducing the size of ice crystals by increasing the efficiency of heat removal. In recent years, many studies have been carried out in which the authors try to use the effect of magnetic and electric fields on the properties of water to improve the freezing of food, ice cubes, feed, living cells (for example, blood, animal tissues and organs), plants, as well as chemical and pharmaceutical products.

To date, a large number of methods for freezing products have been developed. All these methods are aimed at solving the problems of reducing energy losses during freezing, as well as reducing the size of ice crystals. Methods for solving these problems can be classified into methods of accelerating heat removal from the product in devices and methods of influencing free water in products in order to slow or prevent the formation of ice crystals. The acceleration of heat removal is solved either by improving the air blowing of the product, or by using a liquid refrigerant from water to liquid nitrogen.

Thus, an air tunnel quick freezer is known (RU 2278336 C2, published on 06/20/2006), which provides rational air distribution to create symmetrical freezing conditions, reduce the duration of the freezing process, reduce capital costs, and also preserve the quality of food products. The device contains a heat-insulated chamber with a transporting body for freezing products and an air distribution device made in the form of two box-shaped air ducts mounted in parallel on both sides of the transporting body and tapering in the direction of the product, interconnected by a U-shaped manifold connected to the main pipeline. Each air duct has a rod placed longitudinally in its volume with hinged transverse curved plates for passing cooled air from the turborefrigerator unit. Due to the minimum distance between the ceiling of the chamber and the upper branch of the transporting body, which is from 100 to 110 mm, as well as due to the transverse blowing of cold air on the product on the transporting body, the duration of the freezing process is reduced by 30-35%.

Also known (RU 2623242 C1, published on June 23, 2017) is a tunnel freezer that can be used in medicine and pharmacology, in the agro-industrial complex, in the food and meat and dairy industries for quick freezing of a wide range of different products by forced circulation of chilled air. The air coolers in the freezer are installed above and below the metal perforated conveyor belt carrying the product to be cooled. and the other in the freezer area under the bottom cooler. Each of the blocks consists of wire-type electrodes: generating and grounded. In a variant version of the block, the generating electrode can be equipped with needle-shaped EHD elements. When a high voltage is applied to the electrodes of the block, a corona discharge occurs and, as a result, an electric wind forms the conditions for forced electroconvection. The areas where the electrode blocks are located are connected by a bypass, which has built-in electrode blocks at the inlet and outlet, which intensify convection. The regulation of air humidity and frost formation is ensured by an electrode block with wire-type EHD elements placed between the upper cooler and the zone of the bypass outlet channel, which is connected to a voltage source through a voltage divider. As a result, the economic and technological efficiency of the apparatus is increased by reducing energy consumption, reducing the duration of the freezing process, reducing product shrinkage, and ensuring its electroantiseptic treatment.

The disadvantages of the known devices is the low freezing rate due to the low thermal conductivity of the air. For the same reason, ice crystals have time to grow to a size that destroys the walls of the cellular structure of products, which leads to a deterioration in the taste and presentation of thawed products. The prototype does not provide bactericidal treatment of products.

Another analogue of the proposed solution is the invention according to patent RU 2472080 C2 (published on January 10, 2013), which discloses a method and device for the production of frozen foods. The device for the production of frozen products according to the invention contains a freezing bath installed in the freezer, in which there is a freezing agent for immersing the frozen products in it, units for blowing the products frozen in the freezing bath with gas at a temperature of 0°C or lower in order to remove the freezing agent left on the products, and a device for transferring the products to be frozen in the freezer so that the products to be frozen are immersed in the freezing agent in the freezing bath, and then lifted up and taken out of the freezing bath, and the freezing agent remaining on products, removed with gas blowing units. The method for producing frozen products by freezing them in a freezer according to the invention includes: a wet freezing operation by immersing the products to be frozen in a freezing agent (alcohol solution) located in a freezer bath installed in the freezer to ensure freezing of the products, the operation of lifting the products, to be frozen, with their removal from the freezer bath. Freezing in an alcohol solution is also proposed in patent CN 112210350 A (published on 01/12/2021). The method for the production of frozen products according to the invention can be carried out by installing sprinklers around the freezer bath to spray the products to be frozen with a freezing agent. At the same time, when performing the wet freezing operation, only parts of these products are immersed in the freezing agent in the freezing bath, and those parts of these products that have not been immersed in the freezing agent are irrigated by means of spraying agents. A similar solution is proposed in the patent document JP 2003322452 (published 11/14/2003).

As disadvantages of the known analogs, it can be pointed out that, first of all, they are not tunnel devices and, therefore, cannot be used to freeze a product stream (for example, on a conveyor). In addition, they do not allow uniform and complete freezing of the product and require additional cold gas blowing, which increases the complexity of the device and its price. Uneven freezing causes cracking and deformation of the product. Also, from the description of analogues it is not clear how the refrigerant vapor and air are separated to prevent its loss to evaporation.

Patent documents JP 2003161558 (published on 06/06/2003), RU 2720377 C2 (published on 04/29/2020) describe devices and methods in which water molecules in a product are affected by various electromagnetic or acoustic fields, while the purpose of the impact is the vibration of water molecules, preventing the formation of large ice crystals (JP 2003161558 - the freezing process occurs under the action of ultrasound, RU 2720377 C2 - the product is exposed to a microwave field when cooled by air). As a result, the above two effects make it possible to pass through the temperature range of 0°C (-20°C, in which free water crystals grow during freezing, in a very short period of time. In this case, fine ice crystals are formed.

Patent document RU 2270407 C2 (published on February 20, 2006) can be chosen as the closest analogue, which discloses a quick freezing method and a quick freezing installation (options). The known solution proposes a method of rapid cooling. It provides for lowering the air temperature around the object to be frozen to -30…-100°C and applying a unidirectional magnetic field to it. The object is affected by an air stream having a speed of 1 ... 5 m / s. A sound wave of an audible frequency range is applied to this air stream. It is possible to apply an electric field to the object of freezing. The installation contains a freezer capable of lowering the temperature to -30…-100°C, a pulsating magnetic field generator, a fan for circulating cold air in the freezer, and a sound wave generator. To apply an electric field with an intensity of 100...1000 kV/m to the central part of the freezer, the installation contains an electric field generator. The pulsating magnetic field generator includes permanent magnets for applying a static magnetic field to the central part of the freezer with the intensity of a given reference level and electromagnetic coils for applying a pulsating magnetic field that pulsates within a predetermined range relative to the static magnetic field in the central part of the freezer.

The above-described known solutions reduce the size of ice crystals in the polycrystalline structure of frozen water, but do not prevent their occurrence during the freezing process, as well as their accretion and further growth due to the molecules of bound water during storage. The processes of inevitable accretion of primary crystals and their further growth (due to dehydration of the tissues of the frozen object adjacent to the crystals) lead to complete or partial mechanical destruction of cellular and intercellular structures and, consequently, to an inevitable deterioration in the quality of the consumed product. This remark applies to all currently existing freezing methods.

Thus, the analysis of the prior art has shown that there is a need to create a device that would eliminate all the disadvantages of the known solutions.

DISCLOSURE OF THE INVENTION

The technical result to be achieved by the proposed group of inventions is:

- ensuring the prevention of the formation of ice crystals when freezing food,

- ensuring continuous in-line freezing of food products,

- ensuring fast and efficient heat removal from the food product,

- ensuring long-term preservation of the organoleptic properties and physico-chemical characteristics of the food product,

- providing a reduction in the time of freezing food compared to other methods of freezing.

The technical results are achieved by the fact that, as the first variant of the technical solution, a device for freezing water-containing food products has been developed, which is a tunnel-type quick-freezing equipment and contains a heat-insulated chamber, a chain conveying device equipped with clamping brackets, inlet and outlet conveyor belts, containers, a bath for liquid coolant, cooling system, filtration and pumping units, fan unit, control and monitoring unit and paired modules with electrode matrices, equipped with an electric field generator, while the liquid coolant bath is made single-channel, with the possibility of rapid cooling of the food product in the channel until it reaches temperature storage, set in the range from -15°C to -20°C, and paired modules with electrode matrices contain upper electrode matrices, grouped into upper electrode plates, to which a high-voltage potential is applied. alternating current from the electric field generator, and the lower electrode arrays, grouped into the lower electrode plates, which are grounded, the upper electrode plates are mounted above the container movement horizon, the lower electrode plates are mounted directly on the bottom of the liquid coolant bath channel, while the paired modules of the electrode arrays provide simultaneously with the start of rapid cooling of the food product, the creation of an inhomogeneous alternating electric field around the frozen food product with static intensity gradients, and the control and monitoring unit controls the switching on of the electrode potentials on the electrode matrices until the water-ice phase transition is completed.

Matrices of electrodes can be planar or volumetric. The electrodes of the electrode arrays can be point or linear. The step of the electrodes in the electrode matrices is at least 5 mm, and the distance between the electrode matrices is from 20 to 500 mm.

The voltage on the electrodes of the electrode arrays is from 3 to 70 kW, and the frequency of the alternating field is from 1 kHz to 20 kHz.

The moment of completion of the water-ice phase transition is determined by a decrease in the electrical conductivity of the food product by more than 5 times.

The cyclic frequency of movement of the areas of the static gradient of the inhomogeneous alternating electric field is from 5 to 150 Hz. Each change in the direction of movement of the static gradients of the inhomogeneous alternating electric field is accompanied by an inversion of the areas of static gradients of the inhomogeneous alternating electric field by 180 degrees.

The containers are replaceable and are made with wide sides for pressing them against the sides of the liquid coolant bath by means of the clamping arms of the chain transport device. Containers may have a perforated bottom.

The temperature of the liquid refrigerant in the bath is maintained in the range from -40°C to -45°C. The thickness of the refrigerant layer in which the container is immersed is from 3 to 10 cm.

Ethanol acts as a liquid refrigerant.

The freezing time of the food product in the channel of the liquid coolant bath is 3 to 15 minutes.

The technical results are also achieved by the fact that, as the second variant of the technical solution, a device for freezing water-containing food products has been developed, which is a tunnel-type quick-freezing equipment and contains a heat-insulated chamber, a chain conveying device equipped with clamping brackets, inlet and outlet conveyor belts, containers, a bath for liquid refrigerant, cooling system, filtration and pumping units, fan unit, control and monitoring unit and paired modules with electrode matrices, equipped with an electric field generator, while the liquid refrigerant bath is multi-channel, with the possibility of rapid cooling of the food product until it reaches the storage temperature , set in the range from -15°C to -20°C, and the chain conveying device is designed to ensure synchronous movement of containers through all channels of the multi-channel bath for liquid refrigerant, and pa Rigid modules with electrode matrices contain upper electrode matrices, grouped into upper electrode plates, to which a high-voltage alternating current potential is supplied from an electric field generator, and lower electrode matrices, grouped into lower electrode plates, which are grounded, the upper electrode plates are mounted above the container movement horizon , the lower electrode plates are mounted directly on the bottom of each channel of the liquid coolant bath, while the paired modules of the electrode matrices provide, simultaneously with the start of rapid cooling of the food product, the creation of an inhomogeneous alternating electric field around the frozen food product with static intensity gradients, and the control and monitoring units control the switching on potentials on the electrode arrays, carried out until the completion of the water-ice phase transition.

Matrices of electrodes can be planar or volumetric. The electrodes of the electrode arrays can be point or linear. The step of the electrodes in the electrode matrices is at least 5 mm, and the distance between the electrode matrices is from 20 to 500 mm.

The voltage on the electrodes of the electrode arrays is from 3 to 70 kW, and the frequency of the alternating field is from 1 kHz to 20 kHz.

The moment of completion of the water-ice phase transition is determined by the decrease in the electrical conductivity of the food product.

The cyclic frequency of movement of the areas of the static gradient of the inhomogeneous alternating electric field is from 5 to 150 Hz. Each change in the direction of movement of the static gradients of the inhomogeneous alternating electric field is accompanied by an inversion of the areas of static gradients of the inhomogeneous alternating electric field by 180 degrees.

The containers are interchangeable and are made with wide sides for pressing them against the sides of the liquid refrigerant bath by means of the clamping brackets of the chain transport device. Containers may have a perforated bottom.

The temperature of the liquid refrigerant in the bath is maintained in the range from -40°C to -45°C. The thickness of the refrigerant layer in which the container is immersed is from 3 to 10 cm.

Ethanol acts as a liquid refrigerant.

The freezing time of the food product in the channels of the liquid coolant bath is from 3 to 15 minutes.

In addition to the above technical results, the second variant of the technical solution allows to increase the productivity of the equipment, reduce the cost of the equipment and the cost of its operation (by reducing the specific refrigerant demand and the cost of cooling it).

BRIEF DESCRIPTION OF THE DRAWINGS

On FIG. 1 is a schematic front view of a tunnel device for freezing water-containing foodstuffs.

On FIG. 2 is a sectional view of the front view of a tunnel freezer for water-containing foodstuffs.

On FIG. 3 is a schematic plan view of a tunnel device for freezing aqueous foodstuffs.

On FIG. 4 shows a plan view of a tunnel freezer for water-containing foodstuffs with a single-channel bath.

On FIG. 5 is a top sectional view of a tunnel freezer for aqueous foodstuffs with a multi-channel bath (in particular a three-channel bath).

On FIG. 6A and 6B show a side view of a tunnel freezer for water-containing foodstuffs with a single-channel bath from the side of the supply window, FIG. 6A is a general view, Fig. 6B is a sectional view.

On FIG. 7A and 7B show a side view of a tunnel freezer for water-containing foodstuffs with a multi-channel bath (in particular, a three-channel bath) from the side of the supply window, FIG. 7A is a general view, fig. 7B is a sectional view.

On FIG. 8A and 8B show a side view of a tunnel freezer for water-containing foodstuffs with a single-channel bath from the side of the dispensing window, FIG. 8A is a general view, fig. 8B is a sectional view.

On FIG. 9A and 9B show a side view of a tunnel freezer for water-containing foodstuffs with a multi-channel bath (in particular a three-channel bath) from the feed window, FIG. 9A is a general view, Fig. 9B is a sectional view.

SUMMARY OF THE INVENTION

Two variants of a tunnel device for freezing water-containing foodstuffs, which is a quick-freezing tunnel-type equipment, are proposed.

The elements of the proposed device options are indicated on all drawings (Fig. 1 - Fig. 9B) with the following positions:

- heat-insulated chamber (1),

- transport feeding tape (2),

- chain conveying device (3),

- clamping bracket (4),

- container (5),

- transport outlet tape (6),

- bath for liquid refrigerant (7),

- filtration plant (8),

- pumping unit (9),

- cooling system (10),

- fan unit (11),

- control and monitoring unit (12),

- top electrode matrices (13),

- lower electrode matrices (14),

- feed window (15),

- dispensing window (16),

- channel (17),

- electric field generator (18).

In both versions of the proposed group of inventions, the thermally insulated chamber (1) is a tunnel chamber and is equipped with a supply window (15) and an output window (16) of containers (5), designed to ensure the tightness of the device (Fig. 1-2). The tightness of the tunnel chamber prevents refrigerant vapor from escaping to the outside and can significantly reduce the loss of liquid refrigerant to evaporation. In addition, tightness prevents the spread of odor.

In both variants of the proposed group of inventions, the conveying feeding belt (2) is intended for feeding containers (5) to the chain conveying device (3) and is associated with the supply window (15) without violating the tightness of the heat-insulated chamber (1). The transport outlet tape (6) is intended for issuing containers (5) from the chain conveying device (3) and is associated with the issuing window (16) without violating the tightness of the heat-insulated chamber (1) (Fig. 2).

In both versions of the proposed group of inventions, containers (5) are trays for moving water-containing food products and are made with wide sides for pressing them against the sides of the bath (7) for liquid refrigerant. Containers (5) are replaceable. The containers (5) may have a solid bottom or a perforated bottom.

In both versions of the proposed group of inventions, the chain conveying device (3) is equipped with pressure brackets (4) that press the containers (5) against the sides of the liquid refrigerant bath (7) during movement.

In both versions of the proposed group of inventions, the bath (7) is designed to circulate liquid refrigerant flows.

According to the first variant of the proposed group of inventions, the bath (7) contains one channel (17) for the liquid refrigerant, i.e. bath (7) is single-channel (Fig. 4, 6A-6B, 8A-8B).

According to the second version of the proposed group of inventions, the bath (7) contains several channels (17) for liquid refrigerant, i.e. bath (7) is multichannel (Fig. 5, 7A-7B, 9A-9B). The chain conveying device (3) is configured to ensure synchronous movement of the containers (5) along all channels (17) of the multi-channel bath (7) for liquid refrigerant. The chain conveying device (3) contains parallel links according to the number of channels (17) of the multi-channel bath (7) for liquid refrigerant.

In both versions of the proposed group of inventions, at the inlet of the container (5) into the bath (7), the temperature of the frozen products is from +1°C to +5°C, at the outlet of the container (5) from the bath (7), the temperature of the frozen products is -20° C.

In both versions of the proposed group of inventions, the liquid refrigerant circulates continuously through the cooling system (10) to maintain the set temperature. The liquid refrigerant temperature is maintained between -40°C and -45°C. The thickness of the refrigerant layer into which the container (5) is immersed is between 3 and 10 cm.

In both versions of the proposed group of inventions, the author of the present invention proposes to use ethanol as a liquid refrigerant with high thermal conductivity and a freezing point well below the freezing point of the product. Ethanol is completely harmless to the human body. In addition, ethanol has disinfectant and sterilizing characteristics and cleans the product (eg berries) or packaging.

Also, the author of the present invention has taken into account that ethanol removes heat much better compared to air flow and, in addition, it is inexpensive and safe compared to liquid nitrogen. At the same time, a small temperature difference between the temperature of the product and the temperature of ethanol (unlike liquid nitrogen) prevents the product from cracking. In addition, when defrosting, the product frozen in the ethanol-based tunnel chamber goes through the defrosting stage better while maintaining the original freshness.

As a result, in both versions of the device, according to the invention, the food product, when used as a liquid refrigerant ethanol, passes the crystallization temperature range (-1 ... -5 ° C) at high speed, which, together with the use of a non-uniform alternating electric field static tension gradient, prevents the formation of ice crystals and the absence of degradation of the internal cells of the product.

In both versions of the proposed group of inventions, before entering the cooling system, the refrigerant is filtered in a filtration unit (8) to purify the refrigerant, i.e. to remove contaminants that may be on the food product or its packaging. As a filtration unit (8) any standard filtration unit can be used. The pump unit (9) is designed to pump the refrigerant through the filter unit and the cooling system (10) (Fig. 2).

In both versions of the proposed group of inventions, paired modules with electrode matrices are equipped with an electric field generator (18). An electric field generator (18) is connected to each electrode array. Paired modules with electrode matrices contain upper electrode matrices (13), grouped into upper electrode plates, to which a high-voltage alternating current potential is supplied from an electric field generator (18), and lower electrode matrices (14), grouped into lower electrode plates, which are grounded .

In both versions of the proposed group of inventions, the pair modules of the electrode matrices are made with the possibility of creating, simultaneously with the start of rapid cooling, an inhomogeneous alternating electric field with static strength gradients around the frozen food product. An inhomogeneous alternating electric field is characterized by static gradients of the field strength at each point of the field, controlled by the movement of the regions of which organizes the circulation of water dipoles along closed trajectories. Each region of the static gradient of the inhomogeneous alternating electric field is a cone with its apex facing the electrode.

In both variants of the proposed group of inventions, the electrode matrices can be planar or volumetric. The electrodes of the electrode arrays can be point or linear. This applies both to the upper electrode matrices (13) and to the lower electrode matrices (14).

According to the first version of the proposed group of inventions, the upper electrode plates of the upper electrode matrices (13) are mounted above the movement horizon of the containers (5), the lower electrode plates of the lower electrode matrices (14) are mounted directly on the bottom of the channel (17) of the bath (7) for liquid refrigerant.

According to the second version of the proposed group of inventions, the upper electrode plates of the upper electrode matrices (13) are mounted above the movement horizon of the containers (5), the lower electrode plates of the lower electrode matrices (14) are mounted directly on the bottom of each channel (17) of the bath (7) for liquid refrigerant.

In both versions of the proposed group of inventions, when a high-voltage alternating current potential is applied to the upper electrode plates, an electric field is created in the spaces between each upper electrode plate and the lower electrode plate, and the direction of the electric field periodically changes to the opposite with a frequency of 5 to 150 Hz. The step of the electrodes in the matrices is at least 5 mm, and the distance between the matrices of electrodes is from 20 to 500 mm. The specified parameters of the electric field - the voltage on the electrodes of the matrix from 3 to 70 kW; and the frequency of the alternating field is from 1 kHz to 20 kHz.

In both versions of the proposed group of inventions, the control and monitoring unit (12) controls the switching on of the electrode potentials on the electrode arrays, carried out until the completion of the water-ice phase transition.

The control and monitoring unit (12) determines the size, shape of the areas of static gradients of the inhomogeneous alternating electric field, the direction, speed and nature of their movements relative to the food product, which are set programmatically (dynamic program for controlling electrode potentials on electrode matrices). Also, the control and monitoring unit (12) regulates the speed of movement of the chain conveying device (3) and the rate of recirculation of the liquid refrigerant depending on the indicators of the food freezing process (temperature, degree of freezing, etc.).

The control of changes in the direction, speed and nature of the movement of static gradients of the intensity of an inhomogeneous alternating electric field relative to the food product is carried out by alternately switching on the electrode potentials on the electrode matrices. The cyclic movement of water dipoles formed in this way along closed trajectories (vortex movement of groups of water molecules) creates the effect of viscosity, which leads to the formation of solid ice with a glassy structure. Those. Turning on the electrode potentials on the electrode arrays organizes the cyclic movement of water dipoles along closed trajectories with the formation of glassy ice that does not contain crystals. The cyclic movement of water dipoles along closed trajectories is organized by organizing reciprocating cycles of moving areas of a static gradient of the inhomogeneous alternating electric field along the horizontal plane of the cooled object.

Thus, in both versions of the proposed group of inventions, the direction, speed and nature of the movements of the static gradients of the inhomogeneous alternating electric field at each point of the field are controlled by organizing reciprocating cycles of moving the areas of the static gradient of the inhomogeneous alternating electric field along the horizontal plane of the cooled object. The cyclic frequency of movement of the areas of the static gradient of the electric field is from 5 to 150 Hz.

In one cycle of movement of the areas of the static gradient of the electric field strength, the value of the step-by-step (one step is the minimum distance between the electrodes) uniform translational movement is equal to half the width of the region, the value of the step-by-step return movement is half the width of the region minus the minimum distance between the electrodes in the matrix. In one second, the horizontal displacement of the cycle start point is, respectively, from 5 to 150 distances between the electrodes in the matrix. Each change in the direction of movement of static gradients of the electric field intensity is accompanied by an inversion of the areas of static gradients of the alternating electric field by 180 degrees.

Areas of static gradients of the electric field strength move relative to the object of freezing (a food product of organic or inorganic origin) by applying potentials to the electrodes to create a vortex group motion of dipole water molecules in the volume of the object. As a result, the water dipole moves along a cyclic trajectory under the action of static strength gradients.

The inversion of the regions of the static gradient of the alternating electric field inside the reciprocating cycle when changing the direction of their movement and the shift of the cycle start point in the direction of the translational movement after each cycle makes it possible to cover all water dipoles with the vortex motion. The cycle frequency and displacement step form different modes of vortex motion and affect the size of convective cells (a convective cell is a closed trajectory of a dipole (or a group of dipoles) of water) and the degree of intensity of their energy interaction (heat transfer from inside an aqueous solution to its surface). The smaller the size of the local areas of the field, that is, the smaller the step between the electrodes, the greater the number of convective molecular cells of water in the liquid medium of the object to be frozen. The higher the speed of movement of local areas of static gradient fields relative to the object, the smaller the size of these convective cells. The size and number of convective cells is determined by the specifics of the food product. The higher the percentage of water content in the product, the lower the speed of movement of local areas and the larger the size of convective cells.

In both versions of the proposed group of inventions, the impact on the food product by static gradients of the electric field strength moving relative to the food product, as well as the control of the directions, speed and nature of their movements, is carried out throughout the entire water-ice phase transition.

In both versions of the proposed group of inventions, the moment of termination of exposure to a non-uniform alternating electric field on a food product is determined by the moment of completion of the water-ice phase transition, which, in turn, is determined by a decrease in the electrical conductivity of the food product. The electrical conductivity of a frozen food product is reduced by 5 times or more.

In both versions of the proposed group of inventions, after the completion of the water-ice phase transition, i.e. after the end of exposure to a non-uniform alternating electric field on the food product, rapid cooling is continued until the food product reaches the storage temperature specified in the range from -15°C to -20°C.

In both versions of the proposed group of inventions, after leaving the liquid coolant bath (7), the containers (5) are blown with air by means of a fan unit (11), while the refrigerant residues fall in the form of droplets back into the liquid coolant bath (7).

The time for the container (5) to pass through the device in both versions of the proposed group of inventions is from 3 to 15 minutes and depends on the temperature of the products at the outlet of the container (5) from the bath (7) set in the control and monitoring unit (12).

IMPLEMENTATION OF THE INVENTION

The proposed device options can be implemented as follows.

To confirm the possibility of implementing the stated purpose and achieving the stated technical results, two devices were mounted in configurations according to the first and second versions of the proposed group of inventions. The first option (TF-1) is a single-channel tunnel device, the second option (TF-3) is a three-channel tunnel device. The following embodiments of the invention are special cases of the claimed group of inventions and do not limit the scope of the claims.

All devices contained a heat-insulated chamber (1) with a supply window (15) and an output window (16), a chain conveying device (3) equipped with clamping brackets (4), containers (5), transport tapes: inlet and outlet (2 and 6 ), bath (7) for liquid refrigerant with channel(s) (17), filtration unit (8), pumping unit (9), cooling system (10), fan unit (11), control and monitoring unit (12), steam modules with upper (13) and lower (14) electrode matrices and an electric field generator (18).

On all devices, a series of experiments on freezing food (strawberries and tomatoes) was carried out. To compare the results, similar experiments were carried out on the equipment of XINXUDONG, Shandong, China. The matching equipment is a single-channel and three-channel device, respectively SD-100 and SD-300.

Design features of device configurations are presented in Table 1.

Table 1

TF-1 TF-3 SD-100 SD-300 Bath One channel three channels One channel three channels Conveyor belt one one one one Containers

Сменные лотки с перфорированным дном

Interchangeable trays with perforated bottom Solid Bottom Trays Interchangeable trays with perforated bottom Solid Bottom Trays refrigerant Ethanol 96% Ethanol 96% Air Air matrices planar volumetric (two half rings) - - Matrix electrodes pinpoint linear - - Device power, kW 12 12 fifteen fifteen Device dimensions, m 4*1.4*2.0 4*2.2*2.0 7*1.5*2.1 12*2.3*2.3 Voltage, V 380 380 380 380 Electrode pitch, mm 5 ten - - Distance between electrode matrices, mm 150 500 - -

The conditions and results of the experiments for single-channel devices are presented in Table 2.

table 2

Name of indicator tomatoes strawberries TF-1 SD-100 TF-1 SD-100 Productivity, kg/h 152 91 128 83 Total processed raw materials in the experiment, kg 500 1500 500 1500 Product inlet temperature, °C twenty twenty twenty twenty Product outlet temperature, °C -twenty -twenty -twenty -twenty Time spent, total, hour 3.3 5.5 3.9 6.0 Average cooling time to 0°C, min 4.2 16 3.0 fourteen Average cooling cycle time down to -20°С fifteen 69 12 46

The conditions and results of experiments for multichannel devices are presented in Table 3.

Table 3

Name of indicator tomatoes strawberries TF-3 SD-300 TF-3 SD-300 Productivity, kg/h 388 232 326 212 Total processed raw materials in the experiment, kg 1500 1500 1500 1500 Product inlet temperature, °C twenty twenty twenty twenty Product outlet temperature, °C -twenty -twenty -twenty -twenty Time spent, total, hour 3.4 5.5 4.0 6.0 Average cooling time to 0°C, min 4.5 19 4.0 16 Average cooling cycle time down to -20°С fifteen 76 13 54

The end point of the electric field impact on the product was determined by measuring the electrical conductivity. When the electrical conductivity dropped to 5 μS/cm, the field action ceased (the water completely passed into the solid phase). The electrical conductivity was measured with a Valagro conductometer.

All samples frozen under the influence of an inhomogeneous alternating electric field have been stored for 36 months, while selective checks (by defrosting single samples) carried out every six months show that there has been no decrease in their consumer properties and changes in the physicochemical characteristics of objects to be frozen .

The results of tests of devices according to the proposed group of inventions indicate a significant increase in the performance of devices compared to tunnel quick-freezing devices operating on traditional principles. This is evidenced by the increase in the productivity of single-channel and three-channel devices, respectively, by 54-67%, depending on the type of product, with identical processing volumes.

When using both variants of devices according to the proposed group of inventions, fast and efficient heat removal from the food product is ensured. This is evidenced by a significant (fourfold) reduction in the cooling time of the product to 0°C. Also, the test results of devices according to the proposed group of inventions show that complete prevention of the formation of ice crystals during freezing of water-containing food products, as well as continuous in-line freezing of water-containing food products, is ensured. This is evidenced by the fact that the time required for freezing to storage temperature (-20°C) was reduced by 4 times in mass production compared to the traditional method. This also indicates that during the freezing of products, the prevention of the formation of ice crystals is ensured.

In addition, the test results indicate that, according to the second version of the proposed group of inventions, the productivity of the equipment increases, the cost of the equipment and the cost of its operation are reduced (by reducing the specific refrigerant demand and the cost of cooling it). In this case, the increase in productivity occurs in multiples of the number of bath channels for the liquid coolant of the device.

Thus, the tests have shown that the proposed group of inventions ensures the achievement of all the claimed technical results.

Claims (26)

1. A device for freezing water-containing food products, which is a quick-freezing tunnel-type equipment and contains a heat-insulated chamber, a chain conveying device equipped with clamping brackets, inlet and outlet conveyor belts, containers, a liquid refrigerant bath, a cooling system, a filtration and pumping unit, a block fans, a control and monitoring unit and paired modules with electrode arrays, equipped with an electric field generator, while the liquid coolant bath is made single-channel, with the possibility of rapid cooling of the food product in the channel until it reaches the storage temperature specified in the range from -15°C to -20°C, ethanol acts as a liquid coolant, and pair modules with electrode matrices contain upper electrode matrices, grouped into upper electrode plates, to which a high-voltage alternating current potential is supplied from an electric field generator, and m the lower electrode arrays are grouped into lower electrode plates that are grounded, the upper electrode plates are mounted above the container movement horizon, the lower electrode plates are mounted directly on the bottom of the channel of the liquid coolant bath, while the paired modules of the electrode matrices provide, simultaneously with the start of rapid cooling of the food product, the creation around the frozen food product of an inhomogeneous alternating electric field with static intensity gradients, and the control and monitoring unit controls the switching on of the electrode potentials on the electrode matrices, carried out until the completion of the water-ice phase transition. 2. The device according to claim. 1, characterized in that the matrix of electrodes can be planar or volumetric. 3. The device according to claim 1, characterized in that the electrodes of the electrode arrays can be point or linear. 4. The device according to claim 1, characterized in that the step of the electrodes in the electrode matrices is at least 5 mm, and the distance between the electrode matrices is from 20 to 500 mm. 5. The device according to claim 1, characterized in that the voltage on the electrodes of the electrode arrays is from 3 to 70 kW, and the frequency of the alternating field is from 1 kHz to 20 kHz. 6. The device according to claim 1, characterized in that the moment of completion of the water-ice phase transition is determined by a decrease in the electrical conductivity of the food product by more than 5 times. 7. The device according to claim 1, characterized in that the cyclic frequency of movement of the areas of the static gradient of the inhomogeneous alternating electric field is from 5 to 150 Hz. 8. The device according to claim 1, characterized in that each change in the direction of movement of the static gradients of the inhomogeneous alternating electric field is accompanied by an inversion of the areas of static gradients of the inhomogeneous alternating electric field by 180 degrees. 9. The device according to claim 1, characterized in that the containers are replaceable and are made with wide sides for pressing them against the sides of the liquid refrigerant bath by means of clamping brackets of the chain transport device. 10. Device according to claim 9, characterized in that the containers may have a perforated bottom. 11. The device according to claim. 1, characterized in that the temperature of the liquid refrigerant in the bath is maintained in the range from -40°C to -45°C. 12. The device according to claim 1, characterized in that the thickness of the refrigerant layer into which the container is immersed is from 3 to 10 cm. 13. The device according to claim 1, characterized in that the freezing time of the food product in the channel of the liquid refrigerant bath is from 3 to 15 minutes. 14. A device for freezing water-containing food products, which is a quick-freezing tunnel-type equipment and contains a heat-insulated chamber, a chain conveying device equipped with clamping brackets, inlet and outlet conveyor belts, containers, a liquid refrigerant bath, a cooling system, a filtration and pumping unit, a block fans, a control and monitoring unit and paired modules with electrode arrays, equipped with an electric field generator, while the liquid coolant bath is multi-channel, with the ability to quickly cool the food product until it reaches the storage temperature specified in the range from -15 ° C to -20 °C, ethanol acts as a liquid refrigerant, and the chain conveying device is designed to ensure synchronous movement of containers along all channels of a multi-channel bath for liquid refrigerant, and pair modules with electrode matrices contain matrices of electro the upper ones, grouped into the upper electrode plates, which are supplied with a high-voltage alternating current potential from the electric field generator, and the lower electrode arrays, grouped into the lower electrode plates, which are grounded, the upper electrode plates are mounted above the container movement horizon, the lower electrode plates are mounted directly on at the bottom of each channel of the bath for liquid refrigerant, while the paired modules of the electrode matrices provide, simultaneously with the start of rapid cooling of the food product, the creation of an inhomogeneous alternating electric field around the frozen food product with static strength gradients, and control and monitoring units control the switching on of potentials on the electrode matrices, carried out before the moment of completion of the water-ice phase transition. 15. The device according to claim 14, characterized in that the electrode matrices can be planar or volumetric. 16. The device according to claim 14, characterized in that the electrodes of the electrode arrays can be point or linear. 17. The device according to claim 14, characterized in that the step of the electrodes in the electrode matrices is at least 5 mm, and the distance between the electrode matrices is from 20 to 500 mm. 18. The device according to claim 14, characterized in that the voltage on the electrodes of the electrode arrays is from 3 to 70 kW, and the frequency of the alternating field is from 1 kHz to 20 kHz. 19. The device according to claim 14, characterized in that the moment of completion of the water-ice phase transition is determined by a decrease in the electrical conductivity of the food product by more than 5 times. 20. The device according to claim 14, characterized in that the cyclic frequency of movement of the regions of the static gradient of the inhomogeneous alternating electric field is from 5 to 150 Hz. 21. The device according to claim 14, characterized in that each change in the direction of movement of the static gradients of the inhomogeneous alternating electric field is accompanied by an inversion of the areas of static gradients of the inhomogeneous alternating electric field by 180 degrees. 22. The device according to claim 14, characterized in that the containers are replaceable and are made with wide sides for pressing them against the sides of the liquid refrigerant bath by means of clamping brackets of the chain transport device. 23. Device according to claim 22, characterized in that the containers may have a perforated bottom. 24. The device according to claim 14, characterized in that the temperature of the liquid refrigerant in the bath is maintained in the range from -40°C to -45°C. 25. The device according to claim 14, characterized in that the thickness of the refrigerant layer into which the container is immersed is from 3 to 10 cm. 26. The device according to claim 14, characterized in that the freezing time of the food product in the channels of the liquid refrigerant bath is from 3 to 15 minutes.

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