JP2023505742A - Method, apparatus and computer program for thawing frozen or deep-frozen food - Google Patents

Abstract

A method according to the invention for thawing frozen or deep-frozen food products comprises the steps of S1.1) providing a portion of frozen or deep-frozen food product (7); S1.3) applying ultrasound to the food to be treated (7) through the treatment liquid (5) to diffuse the ultrasonic waves into the food to be treated (7). and sending. This allows the food to thaw faster and better retain its organic qualities. The invention also relates to a device and a computer program for carrying out said method. The apparatus may comprise a processing vessel (3) whose inner walls are covered with a layer of ice.

Description

(Cross reference to related applications)
This application claims priority from Italian Patent Application Nos. IT102019000024093 and IT102020000021958, the entire contents of which are hereby incorporated by reference.

The present invention relates to a method, apparatus and computer program for thawing frozen or chilled food.

The method, apparatus or computer program can be used, for example, on an industrial scale for supplying wholesalers, supermarkets and large distribution chains in general, restaurants or hotels, and for home or single restaurant, inn or small grocery store use. Both are particularly suitable for thawing food.

Currently, the following methods are used for thawing frozen or deep-frozen foods.
P. 1) Defrosting in a static atmosphere cell. 2) Thawing in air or other gaseous substances with forced convection. 3) thawing in water with or without forced convection; 4) Decompression by Radio Frequency

Defrosting with still air P. 1) has logistical advantages and respective cost-effectiveness for large quantities of products.

Thawing in air with forced convection P. 2) is based on P.S. Faster than thawing by 1), but requires specific equipment sized according to environment and product placement.

Thawing in water P.I. Method 3) is suitable for small quantities of products because water tank management is required. Although the forced convection type speeds up the process, the management becomes more complicated.

Radio wave thawing P. 4) is very fast, but the food is heated unevenly.

On the one hand this entails a strong risk of locally exceeding the food safety temperature set by food safety regulations or in any case by the competent authority, and on the other hand the thawed food becomes very uneven, significantly degrades its organoleptic properties.

In particular, high-frequency decompression P.I. 4) currently does not guarantee that the relevant safety temperature is not exceeded.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above drawbacks and, in particular, to provide a method and apparatus for more uniform and/or rapid thawing of frozen or deep-frozen food products.

According to a first aspect of the invention, the object is achieved by a method having the features of claim 1 .

In a second aspect of the invention, the object is achieved with a device having the features as claimed in claim 19 .

In certain embodiments of the invention, the apparatus comprises a heating system configured to heat the processing liquid contained in the processing vessel.

In certain embodiments of the invention, the apparatus comprises a temperature control system configured to control the temperature of the processing liquid contained in the processing vessel.

In a particular embodiment of the apparatus according to the invention, said temperature control system is arranged to maintain the temperature of said treatment liquid near or equal to said target temperature.

In a particular embodiment of the apparatus according to the invention, the cooling system comprises a cold source configured to provide a flow of processing liquid at a temperature substantially lower than the average temperature of the cooling liquid present in said processing vessel. Prepare.

In a particular embodiment of the apparatus according to the invention, said cold source is arranged in a substantially elevated area of said process vessel.

In a third aspect of the invention, the object is achieved with a computer program having the features of claim 28.

Further features of the invention are the subject matter of the dependent claims.

The advantages achievable by the present invention will become more readily apparent to those skilled in the art from the following detailed description of certain non-limiting embodiments illustrated with reference to the following schematic drawings.
1 is a side view and a functional view of an apparatus for defrosting food according to a first specific embodiment of the invention; FIG. Figure 2 is a perspective view of an apparatus for thawing food according to a second particular embodiment of the invention; Figure 3 is a first partially exploded perspective view of the device of Figure 2; 3 is a partial cross-sectional view according to section IV-IV of the device of FIG. 2; FIG. Figure 3 is a top view of the device of Figure 2; Figure 3 is a first perspective view of a cold source and part of the remaining cooling system of the apparatus of Figure 2; 7 is a side view of the cold source of FIG. 6 and part of the rest of the cooling system; FIG. Figure 3 is a perspective view of the portion of the processing tank in which the ice probe and temperature sensor of the apparatus of Figure 2 are located; 3 is a detail of a partial cross-sectional view according to section IX-IX of the device of FIG. 2; FIG. Fig. 3 shows a detail of a partial cross-sectional view through section plane XX of the ice probe and temperature sensor of the device of Fig. 2; Figure 3 is a perspective view of the recirculation system of the apparatus of Figure 2; Figure 3 is a first partially exploded perspective view of the device of Figure 2; Figure 3 is a perspective view of a heating element of the compressor of the apparatus of Figure 2; Figure 3 is a first perspective view of a cold source and part of the remaining cooling system of the apparatus of Figure 2;

FIG. 1 relates to a device for thawing frozen or deep-frozen food according to a first particular embodiment of the invention.

Figures 2 to 11 instead relate to a device for thawing frozen or chilled food according to a second particular embodiment of the invention.

The apparatus comprises a treatment vessel 3, indicated by general references 1, 1' respectively, configured to contain a quantity of treatment liquid 5 and one or more portions of food 7 to be treated.

Within the treatment vessel 3 , each portion of the food product 7 to be treated can be at least partially immersed in the treatment liquid 5 , more preferably completely immersed in the treatment vessel 3 .

A method for thawing a frozen food or deep-frozen food 7 according to one aspect of the present invention comprises:
S. 1) providing a portion of frozen or chilled food 7 to be processed;
S. B.2) contacting said portion of food to be treated 7 with treatment liquid 5; 3) transmitting ultrasonic waves through the treatment liquid 5 to the food to be treated 7;
including.

As already partially mentioned, step S. In 2) the part of the food product 7 to be treated is brought into contact with the treatment liquid 5 by at least partial immersion in the treatment liquid 5, more preferably by complete immersion.

Said treatment liquid 5, in which the food to be treated 7 is at least partially immersed, is substantially stationary, ie can only be moved within it by natural convective movements, or is flowing, ie forced. They can move by convective motion or be replaced more or less rapidly.

Preferably step S. 1, S. 2, S. In one or more of 3, the portion of food to be treated 7 comprises a containment membrane 9 and a quantity of food to be treated 7 enclosed in containment membrane 9 .

Advantageously, the containment membrane 9 at least chemically separates the quantity of food to be treated 7 from the treatment liquid 5 to prevent the latter from wetting and/or impregnating said quantity of food to be treated 7 .

Preferably, the containment membrane 9 forms a bag containing said quantity of food product 7 to be treated.

Said bag, more generally the membrane, is preferably impermeable to gases and liquids.

Preferably, S.I. 1, S. 2 or S.I. During at least one or more steps of 3, there is an air pressure drop inside the bag 9 relative to the atmospheric pressure of the external environment, causing the film containing the food product 7 to be treated to adhere in at least some areas.

This improves the transmission of the ultrasound to the food to be processed 7, for example by spreading the ultrasound more evenly over the surface of the food to be processed 7 thereby increasing the amount of energy transferred to the food.

The absolute value of said air pressure drop can be, for example, 0.1-0.2 relative bar or more.

More preferably, S.I. 1, S. 2 or S.I. During at least one or more steps of 3, bag 9 substantially forms a vacuum package.

More generally, preferably S. 1, S. 2 or S.I. During at least one or more steps of 3, the containment membrane 9 and the quantity of food to be treated 7 enclosed in the containment membrane 9 essentially form a vacuum package.

Foods 7 to be processed include meat, fish, crustaceans, seafood, cheese, dairy products, vegetables, fruits, broths, soups, sweet or salty pasta, and in some cases, sweet or salty creams, sauces, preserved foods, tomatoes. It can be selected from the group comprising sauces, confectionery and cakes.

At least step S. In 3, said ultrasound preferably has a frequency comprised between 20 kHz and 1000 kHz.

In this regard, the ultrasonic waves are, for example, 20-40 kHz, 40-80 kHz, 80-120 kHz, 120-160 kHz, 200-250 kHz, 250-300 kHz, 300-350 kHz, 350-400 kHz, 400-450 kHz, 450-500 kHz. It is possible to have frequencies configured between
Advantageously, said ultrasound has a frequency comprised between 35 and 40 kHz or between 38 and 40 kHz.

These two frequency bands have proven to be particularly effective for imparting good organoleptic properties to the thawed product.

The treatment liquid 5 can be, for example, water or an aqueous solution of mineral salts.

Advantageously, S. 2 or S.I. During at least one or more steps of 3, preferably in both of them, the treatment liquid 5 is between 0-12°C, for example 0-2°C, 2-4°C, 4-5°C, 4-6 °C, 6-9°C, 9-12°C, 12-15°C, 15-18°C, 18-21°C or 21-23°C.

Advantageously, S. 2 or S.I. During at least one or more steps of 3, preferably during both of them, the treatment liquid 5 has a temperature above 0 degrees Celsius.

For this purpose, S. 2 or S.I. During at least one or more steps of 3, preferably during both of them, the processing liquid may have a temperature of 0.5° C. or higher.

Also for this purpose, said temperature is preferably 21° C. or lower, more preferably 5° C. or lower.

The temperatures mentioned above and the target temperatures mentioned below can be determined by directly measuring or taking into account, respectively, the temperature inside the vessel 3, i.e. the temperature of the processing bath in which thawing takes place, and at suitable points outside the vessel 3 and/or the processing bath. , for example at the temperature sensor 22 or more generally at the outlet duct 27 of the recirculation system described below or by measuring or considering said temperature, respectively.

The target temperatures mentioned below preferably lie within the aforementioned temperature ranges and/or preferably have the aforementioned temperature values.

The temperature range and/or the target temperature of the treatment liquid 5 comprised between 0.5 and 5°C and between 0.5 and 4°C are combined with ultrasonic waves with a frequency comprised between 35 and 40 kHz or between 38 and 40 kHz. It has proven to be particularly effective for obtaining thawed products with excellent organoleptic properties, especially when combined.

Preferably, the containment membrane 9 is composed of one or more materials of polyethylene, polyvinyl chloride (PVC) and ethylene vinyl acetate (EVA).

The encasing membrane 9 has an average thickness comprised, for example, between 50 and 400 μm, between 70 and 150 μm, or between 90 and 130 μm.

Advantageously, S. 2 or S.I. During at least one or more steps of 3, the temperature of the processing liquid 5 is maintained within a predetermined tolerance range.

Said predetermined tolerance range is preferably comprised between 0 and 23°C, more preferably between 0 and 21°C, between 0 and 12°C or between 0 and 5°C.

More preferably, the acceptable range is 4 degrees or more or less, more preferably 2 degrees or more or less, 1 degree or more or less, 0.4 degrees or more, more preferably 2 degrees or more or less than a predetermined thawing temperature, which is preferably unique to each type of food 7 to be processed. Consists of more than or less than 5 degrees.

To this end, the previous teachings regarding the thawing process mentioned above are, in part, as already mentioned:
a processing vessel 3 capable of containing a large amount of processing liquid 5; and an ultrasonic wave generator 15 configured to diffuse ultrasonic waves into the processing liquid 5 contained in the processing vessel 3.
can be advantageously performed with a thawing apparatus comprising

The processing vessel 3 can consist, for example, of an optionally more or less parallelepiped (FIG. 1), cubic or cylindrical tank with an open top (FIG. 1).

The treatment vessel 3 is preferably made of metal, for example stainless steel, so as to inter alia facilitate the transmission and diffusion of the ultrasonic waves generated by the generator 15 into the liquid 5 .

Advantageously, the treatment vessel 3 is covered on the outside with a heat insulating cover 6, which contributes both to keeping the temperature of the treatment bath low and to make it more uniform from point to point. , increasing the energy efficiency of the device 1 .

Each ultrasonic generator 15 may for example be of the piezoelectric type or have a magnetostrictive effect.

Preferably, during normal operation of the apparatus 1 , the ultrasonic generator 15 is positioned external to the container 3 and the bulk of the processing liquid 5 contained in the container 3 to superimpose the liquid 5 through the walls of the container 3 . It transmits sound waves (Fig. 1). In this way the ultrasonic energy is distributed more evenly in the liquid and the food product 7 to be treated. However, in other embodiments not shown, the ultrasonic generator 15 can also be placed in the container 3 and the volume of the processing liquid 5 contained in the container 3, for example immersed in the liquid 5. be.

The device 1 , 1 ′ preferably comprises a plurality of ultrasonic generators 15 which are preferably arranged below the bottom of the container 3 .

Preferably, the ultrasonic generators 15 are fixed to the bottom or in any case the wall of the container 3, for example at a density of 10 to 60 per square meter of the bottom or more generally of the wall of the container 3. having generators 17, such a density can consist of, for example, 20-50 generators 17/m2, 40-50 transducers/m2, or 45-48 transducers/m2 .

Alternatively or in combination, the device 1, 1' comprises a total number of generators 17 comprised between 1 and 30, 2 and 20 or 15 and 18, or a number of ultrasonic generators 17 equal to 17, for example. It is possible to prepare.

Preferably, the ultrasonic generator 15 is or comprises a piezoelectric actuator, although they could obviously consist of different types of actuators.

Advantageously, the apparatus 1 comprises a temperature control system arranged to control the temperature of the processing liquid 5 contained in the processing vessel.

Advantageously, said temperature control system comprises a cooling system 11 , 11 ′ arranged to cool the processing liquid 5 contained in the processing vessel 3 .

The cooling system 11, 11' may for example have a temperature substantially lower than the average temperature of the coolant 5 present in the process vessel or the temperature of the coolant 5 detected at the correct time at the appropriate point in the liquid process. A cold source 110, 110' configured to supply a flow of treatment liquid 5 at .

The cold source 110 , 110 ′ may comprise, for example, a heat exchanger configured for direct immersion in the processing liquid 5 contained in the processing vessel 3 .

The heat exchangers 110, 110' may comprise, for example, a refrigerant liquid such as ammonia, carbon dioxide, water, propane, freon, liquid nitrogen, or a coil through which a suitable chilled refrigerant liquid flows, e.g. and a first heat exchanger (not shown or coincident with heat exchanger 110 for example) acting as an evaporator and a second heat exchanger (not shown) acting as a condenser. ) and an expansion valve (not shown).

Alternatively, the cold source 110 may, for example, be an outlet in a fluid circuit that introduces into the vessel 3 some processing liquid 5 or other fluid, such as suitably blown liquid nitrogen, that is substantially cooler than that already present in the vessel 3. Such a fluid circuit may comprise, for example, a compressor, a first heat exchanger functioning as an evaporator and a second heat exchanger functioning as a condenser, arranged outside the process vessel 3. and an expansion valve (not shown).

Advantageously, the cooling system 11 , 11 ′ is configured to form and maintain an ice deposit on at least a portion, and more preferably all, of the inner wall of the tank or other processing vessel 3 .

Said layer of ice preferably has an average thickness of 1 cm or more, more preferably 2, 4, 6 cm or more and preferably less than 10 cm.

For this purpose, the treatment liquid 5 is substantially different from the eutectic mixture, for example water only or Consists of non-eutectic aqueous mixtures or solutions.

In order to form and preserve a suitable layer of ice, the cooling system 11, 11' is preferably equipped with one or more ice probes 19 (Fig. 9).

Each ice probe 19 has continuous or discretized measurements, e.g. two or more states discretized, i.e. possible measurements, e.g. 3, 5, 10, 20, 50 or more states or By providing a possible measurement value, for example in the form of an analog or digital electrical signal, for example the thickness of the ice layer covering the inner wall of the container 3 can be measured.

Alternatively, each ice probe 19 can simply provide an output signal with only two possible states, 0-1 or on-off, which covers the interior of the tank at or around the probe 19. It simply indicates whether the ice has reached a certain predetermined thickness limit.

In this case, the device 1, 1' is advantageously formed on it, for example by moving the sensitive part of the probe 19 farther or closer in order to adjust the position of the probe 19 with respect to the inner wall of the treatment vessel 3. A probe positioning system can be provided that is configured to adjust the thickness of the ice.

The probe positioning system can advantageously be manually operated, for example by a knob, crank or lever.

the ice layer keeps the average temperature of the treatment liquid 5 detected in the thawing bath or elsewhere in the fluid circuit or detected by the probes 21 and/or 22 within a particularly narrow tolerance range, for example 4° C., And/or the temperature of the processing liquid bath 5 can be accurately maintained in the range of 0.5-5°C or 0.5-4°C.

Also for this purpose, cold sources 110' are advantageously provided, e.g. It may consist of a duct 1100, preferably extending thereover (FIGS. 6, 7).

Preferably, the duct 1100 extends around and outside the processing vessel 3 (Figs. 6, 7). However, in an embodiment not shown, the duct 1100 can extend along the inner wall of the container 3, or in any case close to the container 3, inside said inner wall, in which case the duct 1100 can be used for the treatment liquid 5. It can be directly immersed in a bath.

Preferably, the duct 1100 comprises one or more turns forming, for example, a substantially helical winding, preferably surrounding or otherwise accommodating the container 3 .

Said turns preferably have substantially the same shape as the cross-section of the treatment vessel 3, for example rectangular (FIGS. 6, 7), square, rhombus, polygonal, circular, oval, elliptical cross-section.

Said spiral winding of duct 1100 is particularly effective for covering the inner wall of container 3 with a layer of ice.

Preferably, the helical winding of the duct 1100 extends over at least 20% of the side surface of the process vessel 3 and its perimeter or interior surface, more preferably at least about 30%, 50% of the side surface of the process vessel 3 . %, 70% or 90% of the surface.

Advantageously, the temperature cooling or control system 11, 11' senses the temperature of the treatment liquid bath 5 present in the vessel 3 (Figs. 8, 9, 11) or the temperature elsewhere in the apparatus 1, 1'. It comprises one or more temperature sensors 21, 22 for

During normal operation of the apparatus 1 the first sensor 21 can be immersed in the processing liquid bath 5 present in the container 3 .

The first sensor 21 is, for example, a mechanical or electromechanical thermometer probe intended merely to provide a reading of the detected temperature, or an electrical, electromechanical or electronic sensor which detects the temperature can be sent to logic unit 17 or other logic units in the form of electrical, electronic or optical signals.

The second temperature sensor 22 is for example outside the vessel 3, for example along the outlet duct 27 of the recirculation system or more generally along the outlet duct directing the treatment liquid towards the vessel 3 and/or It can be arranged along an outflow duct for discharging the processing liquid from the vessel 3 .

In an embodiment not shown, the second temperature sensor 22 is arranged in the container 3 and preferably submerged in the bath of thawing liquid 5 .

The device 1 can also have only one of the two temperature sensors 21, 22, or both, and possibly further temperature sensors (not shown).

In order to make the temperature of the processing liquid 5 in the container 3 more uniform, the apparatus 1 preferably comprises a recirculation system 23 arranged to withdraw the processing liquid from the container 3 and supply it again, preferably continuously. (Figs. 3, 11).

Recirculation system 23 may comprise inlet duct 25 , outlet duct 27 and recirculation pump 29 .

The inlet duct 25 is fluidly connected to the container 3 via an inlet opening 250 .

The outlet duct 27 opens into the container 3 through an outlet 270 .

A recirculation pump 29 is arranged to draw treatment liquid from the vessel 3 through duct 25 and supply it again through duct 27 .

Preferably, inlet opening 250 and outlet 270 are positioned relatively apart from each other within container 3, e.g., inlet opening 250 is preferably positioned at the bottom of container 3, while outlet 270 is preferably positioned at the bottom of container 3. placed on top of the

If the container 3 has a substantially rectangular or square plan, the outlet 250 and outlet 270 are preferably located at or near diagonally opposite corners of the plan itself.

Advantageously, the temperature control system 11, 11' consists of a heating system arranged to heat the processing liquid 5 contained in the processing vessel.

Said heating system may be a heat source 13d comprising, for example, a Joule effect resistor, a heat exchanger comprising a coil in which a hot fluid traverses, or arranged for direct immersion in the processing liquid 5 contained in the processing vessel 3. Other heating elements can be provided.

Said coil traversed by the hot fluid may be part of a refrigeration cycle machine, for example a heat pump, or preferably the same refrigerator, acting as a heat pump, to which the compressor 4 belongs, in which case said coil is A duct 1100 may be provided.

Alternatively, the heat source 13 may comprise, for example, an outlet in a fluid circuit that introduces into the vessel 3 some treatment liquid 5 that is substantially warmer than that already present in the vessel 3 .

Advantageously, the temperature control system preferably reduces the temperature of the treatment liquid 5 contained in the treatment vessel to a predetermined threshold while the ultrasonic generator 15 is activated to diffuse ultrasonic waves into the food product 7 to be treated. configured to remain above and/or below.

For this purpose the temperature control system 11, 11' may comprise a logic unit 17, for example a microprocessor, which for example comprises one or more of the temperature sensors 21, 22 and/or Based on the detection of ice probe 19, the operation of possible cold sources 110, 110' and/or hot source 13 is controlled.

To this end, the logic unit 17 controls the operation of one or more of the components of the compressor 4, the refrigerator, the pump 29 in a feedback or open loop manner, for example by controlling the operation of one or more of the possible cold sources. It can be configured to control the operation of 110, 110' and/or the heat source 13.

In particular, the logic unit 17 preferably keeps the temperature of the processing liquid present in the vessel 3 near or equal to a preselected target temperature and/or preselected criteria. to control the operation of the cooling system 11, 11' and/or the heating system such that the point-measured temperature of the treatment liquid 5 is maintained near or coincident with said preselected target temperature. Configured.

For this purpose the logic unit 17 may for example comprise one or more thermostats.

A logic unit 17 or other logic unit (not shown) may control the operation of one or more ultrasound generators 15 and possibly the overall operation of the device 1 .

To facilitate the formation of an ice coating, the logic unit 17 detects when the layer of ice covering the inner wall of the container 3 has insufficient thickness and/or extension, e.g. It is advantageously arranged to start the compressor 4 or more generally the refrigerator or other cold source 110 when the ice thickness is sensed and signaled to the logic unit 17 .

Also, in order to facilitate the formation of the ice coating, the logic unit 17 only detects when the layer of ice covering the inner wall of the container 3 reaches a sufficient thickness and/or elongation, e.g. is advantageously arranged to activate the recirculation system 23 only when it detects and signals the logic unit 17 an ice thickness equal to or greater than .

This threshold thickness is preferably 1 centimeter or more, more preferably 2, 4, 6 centimeters or more.

More generally, the logic unit 17 is advantageously arranged to control the cooling system 11 , 11 ′ so as to generate and preserve an ice shell covering the inner wall of the container 3 .

Advantageously, the cold source 110 is located in a substantially high area of the processing vessel 3, i.e. more than half the maximum depth of the processing vessel 3, so as to create a stronger and wider convection current in the processing liquid 5 contained within the vessel 3. Placed in high areas.

Advantageously, the heat source 13 is located in a substantially lower area of the processing vessel 3, i.e. half the maximum depth of the processing vessel 3, so as to create a stronger and wider convection current in the processing liquid 5 contained within the vessel 3. placed at a lower position than

The container 3 preferably has a volume of between 0.05 and 0.2 cubic meters, or between 0.05 and 0.2 cubic meters.

Such relatively small dimensions make the device 1, 1' particularly suitable for retailers, such as single supermarket stores, fishmongers, restaurants or canteens, or end users which are in any event considered to be of medium size. shall be

The container 3 can in any case have a smaller or larger volume, for example equal to or greater than 0.4 cubic meters.

The device 1, 1' can be manufactured as a cabinet having substantially the general shape of a parallelepiped (Figs. 2, 3, 5), a cube, a prism or a cylinder.

Said cabinet can optionally be slidable on wheels (Fig. 2).

The container 3 is preferably attached to the top of the cabinet.

A compressor 4 , or more generally a refrigerator, if any, for cooling the treatment liquid 5 is preferably enclosed in a cabinet housed below the tank 3 .

The logic unit 17 and/or any other electrical and/or electronic control unit can be arranged in a box 170 (Fig. 13) or other protective shell, for example made of a suitable plastic material.

Advantageously, the compressor 4 comprises a tray 40 arranged to collect any condensed water dripping from the body of the compressor 4, the inner bottom surface of the cabinet which may form the device 1, 1'. This prevents the condensed water from spreading over and wetting the box 170, its contents, and other electrical devices or components, causing electrical shorts or other failures (FIG. 12).

An electrical resistor (not shown) configured to heat and evaporate any water accumulating on the tray 40 by the Joule effect can advantageously be arranged in the tray 40, providing additional resistance for said water. are precisely fitted and positioned to evaporate said water.

This electrical resistance can be operated continuously, eg always on, or it can be operated on and off or even regulated, preferably by a thermostat.

Advantageously, the compressor 4 is provided with one or more heating elements 42, each of which is arranged to heat the compressor so that the compressor remains at a temperature below zero or at any rate very low for an extended period of time. prevents freezing when operating for a period of time, thus preventing traces of oil lubricating its internal mechanisms from contaminating or coming from the coolant fluid directed to the coil 1100 or other cooling ducts 1100 ( 12, 12A).

Traces of oil or other lubricants in the refrigerant fluid compressed by compressor 4 can actually damage the expansion valve and other components of the refrigerator.

Each heating element 42 may be, for example, an electrical resistance that heats the compressor 4 by the Joule effect.

This electrical resistance can, for example, have the shape of a strip that surrounds or extends around the body of the compressor 4 .

Also, in order to avoid or otherwise reduce contamination of the refrigerant liquid caused by the lubricant, the compressor 4 or at any rate each refrigerator filters the refrigerant liquid to retain the lubricant particles associated therewith. Advantageously, one or more filters 44 are provided.

At least one of these filters 44 is preferably placed at a point in the circuit where the refrigerant liquid is normally in the liquid state.

Also, in order to avoid or in any case reduce contamination of the refrigerant liquid by lubricating oil, the compressor 4 or in any case the opposing refrigerator is advantageously provided with one or more solenoid valves 46. , the solenoid valve 46 is closed and configured to close the duct through which the refrigerant liquid passes, for example when the refrigerant liquid reaches or exceeds a suitable temperature threshold and/or when the compressor 4 is switched off. to avoid backflow of refrigerant liquid into the compressor and damage to the laminate valve.

Said cabinet may be provided with a lid 31 foldably secured to the top of the cabinet itself, preferably by suitable hinges, and openable and closable to reveal and cover the tank or other container 3 respectively (Fig. 2, Figure 3).

Advantageously, the lid 31 forms or constitutes a chopping board capable of cutting the thawed product when lowered.

For this purpose, the lid 31 is preferably made of polyethylene or can be covered with a sufficiently thick and rigid layer of polyethylene.

When the possible lid 31 is closed or lowered in any case, the cabinet
total length LM preferably comprised between 0.6 and 4 meters, between 1 and 3 meters, between 1.2 and 2 meters or between 1.2 and 1.5 meters;
overall width WM preferably comprised between 0.3 and 2 meters, between 0.4 and 1 meter or between 0.4 and 0.5 meters; and preferably between 0.3 and 1.5 meters , between 0.5 and 1 m, between 0.6 and 0.9 m or between 0.8 and 0.9 m
has one or more of the exterior overall dimensions of

These external overall dimensions also contribute to making the device 1 particularly suitable for end-users who can be considered retailers or medium-sized businesses anyway.

Advantageously, the device 1, 1' can be provided with a grid 33 for thawing e.g. fish (Fig. 3).

The grid 33 is provided at the bottom of the processing vessel 3 so as to suitably space the various parts of the food product 7 placed on the grid 33 from the ultrasonic generator 15, thereby preventing the latter from being damaged. , or in the vicinity thereof in any case.

An example of operation and use of the decompression device 1, 1' will now be described.

The operator places a portion of the food to be treated 7, preferably comprising the aforementioned bag or other containment membrane 9 and a predetermined amount of the food to be treated, for example a portion of frozen or deep-frozen meat or fish, into the treatment vessel 3. introduced within.

The food portion 7 is completely immersed in a liquid bath, preferably water or an aqueous solution, contained in the treatment vessel 3 .

When the thawing cycle of the apparatus 1 is activated, the one or more ultrasonic generators 15 begin emitting ultrasonic waves that diffuse through the walls of the processing vessel 3 and the bulk of the processing liquid 5 within the food portion 7 to melt the food. The part 7 is thawed because the tissue or any material of the food product 7 vibrated by the ultrasonic waves is heated and mechanical vibrations caused by the ultrasonic waves may be present in the food product 7. This is to break up macroscopic and microscopic ice crystals to increase their exposed surface and thus accelerate their thawing by thermal diffusion.

On the other hand, the temperature control system advantageously maintains the temperature of the water or other treatment liquid 5 within predetermined limits to prevent excessive overheating of the food product 7 locally or, worse, globally. , prevent reaching temperatures considered critical for the growth of microorganisms, especially pathogens.

In particular, the temperature control system 11, 11' can cool the processing liquid 5 when the processing liquid 5 tends to be overheated by the effects of ultrasound or by simple heat exchange with the surrounding environment. The treatment liquid 5 can be heated if the treatment liquid 5 tends to be cooled too much, for example if the temperature of the treatment liquid 5 tends to drop below 0 degrees Celsius or a few degrees Celsius. .

Advantageously, the temperature control system 11, 11' creates and maintains a layer of ice covering the inner surface of the vessel 3, stabilizes the temperature of the processing liquid bath 5, and, as previously mentioned, uses a relatively inexpensive sensor. , probes, and common electrical/electronic components to control this temperature to tight tolerances.

The treatment liquid 5 is thus substantially contained in a bath of ice.

The bag or other waterproof and watertight containment membrane 9 prevents the liquid 5 from contaminating the food product 7 by wetting or otherwise impregnating it, at least in direct, chemical contact, and at the same time caused by cavitation. It transmits mechanical vibrations in a more effective and homogeneous manner and protects the food surface from mechanical or thermal damage caused by cavitation itself, or from the risk of chemical, physical or microbial contamination caused by bathing the empty product in water.

Once thawed, food packages 7 may be removed from treatment bath 5 and used, for example, for cooking or consumption, or may be stored in food establishments, supermarkets or other sales outlets, warehouses of food wholesalers, restaurants, canteens, fishmongers or It can be sent to a point of use such as a butcher, home or other individual consumer.

Starting from a non-operational state, for example at the beginning of a work shift, the apparatus 1' is started by filling the container 3 with water acting as the treatment liquid 5 and activating the compressor 4 and the opposing refrigerator. This allows a cooled refrigerant liquid, such as refrigerant gas rapidly expanded by a laminated valve, to flow into the duct 1000 of the heat exchanger 110'.

Thus, the heat exchanger 110' begins to cool the process liquid 5, ie the water, contained in the container 3 until it covers itself and/or the inner wall of the container 3 with ice shells.

When the ice probe 19 detects, for example, that the ice shell has reached a predetermined threshold thickness around it, the logic unit 17 or other logic unit detects this event and turns on the compressor 4 or in any case the refrigerator. can be stopped. Preferably, at the same time, the logic unit 17 or other logic unit activates the recirculation system 23, for example by activating a possible pump 29 to draw water or process liquid from the container 3 in the inlet duct 25 and draw it there. to the outlet duct 27 from which said water or other processing liquid is supplied again into the vessel 3 to mix the water or other processing liquid 5 in the vessel 3 to make its temperature more uniform and stronger. The food 7 to be processed is cooled more effectively by strong convection.

Logic unit 17 or another logic unit may then, e.g. , the compressor 4 and/or the refrigerator and possibly the heat source 13 can be restarted.

Thawing the food product 7 at a temperature slightly above 0 degrees Celsius contributes significantly to preserving its organic character.

Thanks to the previous teachings, it is possible to thaw frozen or deep-frozen foods much more quickly than in still atmosphere or forced convection cells, compared to thawing times in current air-conditioning cells or current back-air coolers. , the thawing time can be reduced by half or up to a third.

At the same time, the previous teaching makes it possible to preserve very well the organic properties of foods thawed by ultrasound, which is comparable to the known thawing method P.S. 1-P. It gives better results than 4 and allows the creation of a highly effective defrosting device using electronic or electromechanical components and sensors that are not overly valuable and expensive.

Compared to known defrosting by radio frequency, the ultrasonic defrosting method and apparatus described above heats food more uniformly with less local overheating, thus reducing local overheating and significantly extending its shelf life. and reduce the risk of spoilage and bacterial contamination once thawed awaiting sale, consumption or processing.

It has been observed that microflora that may be present in the frozen food are reduced and inactivated by treatment with the device 1, 1'.

The device 1, 1' also allows the product to be stored at the melting temperature of ice, substantially like a cold room, as required by European Union Legislative Decree 853/04.

The embodiments described above are susceptible to numerous modifications and variations without departing from the scope of the invention.

For example, in an embodiment not shown, the portion of food to be processed 7 may lack the containment membrane 9 and consist only of, for example, a predetermined amount of the portion of food to be processed 7 .

The cold source 110 , 110 ′ may also comprise one or more eutectic plates, for example internally or externally fixed to the wall of the vessel 3 .

The walls of the vessel 3 may be hollow and may contain therein glycol or other cooling liquid for cooling the processing liquid bath 7 contained within the vessel 3 .

In other words, the container 3 comprises two tanks, one containing the other, with the thawing liquid contained in the innermost tank and the glycol or other cooling liquid contained in the space between the inner and outer tanks. It is possible to

Any reference herein to "embodiments" or "example embodiments" means that any particular feature or structure described in connection with such embodiments may constitute at least one embodiment of the present invention, and in particular the main claim. are intended to be included within the specific variations of the invention defined in Section 1.

The appearance of such phrases in various places in the specification does not necessarily mean that they are all referring to the same embodiment.

Also, where a feature, element or structure is described in connection with a particular embodiment, it is within the ability of the person skilled in the art to apply that feature, element or structure to other embodiments. is allowed.

Unless otherwise stated, reference numerals that differ only in different citations, eg 21′, 21″, 21 ^III , indicate different variants of like named elements.

Moreover, all details can be replaced by technically equivalent elements.

In fact, the materials used and their dimensions can be of any type according to technical requirements.

Expressions of the type "A comprises B, C and D" or "A is formed by B, C and D" include the specific case "A consists of B, C and D". It must be understood that

Unless otherwise specified, the phrase "A comprises B elements" shall be understood as "A comprises one or more B elements."

Reference to "the first, second, third, ... nth entity" is for the sole purpose of distinguishing them from one another, although the designation of the nth entity is not necessarily the first, second, third, ... nth entity. It does not suggest the existence of the 2nd...(n-1)th entity.

The list of examples and possible variations in this application should be construed as a non-exhaustive list.

Claims (28)

Steps below:
S. 1.1) providing a portion of frozen or chilled food (7) to be processed;
S. S.1.2) contacting a portion of said food to be treated (7) with a treatment liquid (5); 1.3) Sending ultrasonic waves to said food to be treated (7) through a treatment liquid (5) such that the ultrasonic waves diffuse into said food to be treated (7). How to unzip. 2. Method according to claim 1, wherein in at least steps S1.2) and/or S1.3) a portion of the food to be treated (7) is at least partially immersed in a bath of the treatment liquid (5). Steps below:
S. 3.1) providing a process vessel (3) with an inner surface;
S. 3.2) filling said inner surface with an amount of treatment liquid (5) so as to form a bath of treatment liquid (5);
S. S.3.3) covering at least part of said inner surface of the processing vessel (3) with a layer of ice; 3.4) said step S. 1.2) and S. 1.3),
Step S. 3.3) is step S.3. 3. The method of claim 1 or 2, which may also be performed before 2). 3. According to one or more of the preceding claims, comprising controlling the temperature of the treatment liquid (5) by at least cooling the treatment liquid (5) in at least steps S1.2) and/or S1.3). the method of. In at least steps S1.2) and/or S1.3), at least the treatment liquid (5) is heated in order to maintain the temperature of the treatment liquid (5) near or equal to the target temperature. and/or controlling by cooling, wherein the target temperature is comprised between 0° C. and 21° C.
5. The method of at least claim 4. A method according to claim 5, wherein said target temperature is comprised between 0°C and 12°C. A method according to claim 5, wherein said target temperature is comprised between 0°C and 5°C. A method according to one or more of claims 5 to 7, wherein said target temperature is 0.5°C or higher. A method according to one or more of claims 5-8, wherein the target temperature is 4°C or less. A method according to one or more of claims 5 to 9, wherein said target temperature is 5°C or less. Method according to one of claims 5 to 10, comprising maintaining the temperature of the treatment liquid (5) within a tolerance range comprising said target temperature, said tolerance range having a range of 4°C or less. In at least steps S1.2) and/or S1.3), said food to be treated is encapsulated in a containment membrane (9) separating said food to be treated from treatment liquid (5). A method as claimed in the claims. 13. Method according to claim 12, wherein the containment membrane (9) forms a vacuum casing. A method according to one or more of the preceding claims, wherein said ultrasound has a frequency comprised between 20 and 1000 kilohertz. A method according to one or more of the preceding claims, wherein said ultrasound has a frequency comprised between 38 and 40 kilohertz. A method according to one or more of the preceding claims, wherein said ultrasound has a frequency comprised between 35 and 40 kilohertz. The foods to be treated include meat, fish, cold meats, crustaceans, seafood, cheese, dairy products, vegetables, fruits, broths, soups, sweet or salty doughs, optionally sweet or salty creams, sauces, A method according to one or more of the preceding claims, selected from the group comprising canned vegetables, confectionery, cakes. A method according to one or more of the preceding claims, wherein said treatment liquid (5) is water or a substantially non-eutectic aqueous solution or mixture. the following:
a processing vessel (3) capable of containing a large amount of processing liquid (5); and an ultrasonic wave configured to diffuse ultrasonic waves into said processing liquid (5) contained within said processing vessel (3) sound wave generator (15)
A device (1, 1') for thawing frozen or chilled food (7), comprising: 20. Apparatus according to claim 19, comprising a cooling system (11, 11') arranged to cool the treatment liquid (5) contained in the treatment vessel (3). 21. according to claim 19 or 20, wherein said cooling system (11, 11') comprises ducts (1100) extending along and/or adjacent to the walls of said treatment vessel through which a suitable coolant fluid can flow; Apparatus as described. The ducts (1100) of the cooling system (11, 11') form one or more turns extending around and outside or inside the processing vessel (3) to cool the processing vessel (3). 22. The apparatus of claim 21, wherein: 23. Apparatus according to claim 22, wherein the duct (1100) of the cooling system (11, 11') forms one or more turns extending around and outside the processing vessel (3). Said cooling system (11, 11') comprises a compressor (4), a first heat exchanger (110, 110') acting as an evaporator, a second heat exchanger (110, 110') acting as a condenser, and an expansion 24. Apparatus according to one or more of claims 20-23, comprising a refrigerator comprising a valve. a logic unit (17) and one or more sensors and/or probes selected from the group of temperature sensors (21, 22) and ice probes (19), said logic unit (17) comprising said one One or more of claims 20 to 24, arranged to control the cooling (11, 11') system and/or the heating (13) system based on the detection of the above sensors and/or probes. Device. said cooling (11, 11') system and/or heating (13) system to maintain the temperature of the treatment liquid present in the vessel (3) near or to match a preselected target temperature; 26. Apparatus according to one or more of claims 20 to 25, comprising a logic unit (17) adapted to control the operation of. 27. One of claims 19 to 26, comprising a recirculation system (23) configured to withdraw a portion of the processing liquid (5) from the processing vessel (3) and feed it back into the processing vessel (3). A device as in the preceding paragraph. Computer program, adapted to perform the method according to one or more of claims 1 to 18 when run on a computer logic unit.

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