Magnetic field ultrasound-assisted freezing refrigeration device and application thereof

Abstract

The application discloses a magnetic field ultrasonic auxiliary freezing and refrigerating device and application thereof. The magnetic field ultrasonic auxiliary freezing and refrigerating device comprises magnetic field components and ultrasonic components distributed in a two-dimensional plane, the magnetic field components comprise m magnetic field generating devices, the magnetic field generating devices are used for generating a magnetic field environment, the ultrasonic components comprise n ultrasonic generating devices, the ultrasonic generating devices are used for generating an ultrasonic wave environment, at least one of the magnetic field generating devices is arranged between two of the ultrasonic generating devices, or at least one of the ultrasonic generating devices is arranged between two of the magnetic field generating devices, or at least one of the magnetic field generating devices is surrounded by x ultrasonic generating devices, or at least one of the ultrasonic generating devices is surrounded by y magnetic field generating devices, m, n, x and y are positive integers, x is less than or equal to n, and y is less than or equal to m.

Description

Technical Field

[0001] This invention relates in particular to a magnetic field ultrasound-assisted freezing and refrigeration device and its application, belonging to the field of freezing and refrigeration technology. Background Technology

[0002] Low-temperature storage is a common method for preserving food and biochemical samples. Traditional freezing and refrigeration equipment only has temperature control functions. During low-temperature freezing, the rate of ice crystal formation in food and biochemical samples is greater than the rate of water migration. A large number of ice crystals are formed both inside and outside the cells, causing mechanical damage to the sample's cell tissues, affecting protein structure, and resulting in juice loss after thawing, which leads to a decline in the frozen storage quality of food and biochemical samples.

[0003] In recent years, physical field-assisted sample freezing and refrigeration has gradually gained popularity. Food and biochemical samples have different porosities and contain diamagnetic or paramagnetic substances, exhibiting different response characteristics to magnetic fields. By influencing the orientation behavior of diamagnetic or paramagnetic molecules, the orderliness of microscopic particles in the material is altered, promoting the formation of smaller ice nuclei by water molecules during freezing and reducing mechanical damage to the sample tissue. Ultrasound, a type of sound wave, propagates through the air medium, and its oscillation frequency is typically greater than 20 kHz. Ultrasound disrupts the formation of large ice crystals during freezing through cavitation: the higher the frequency, the smaller the cavitation bubbles. These small cavitation bubbles act as heterogeneous nucleation sites for ice crystals, inducing the formation of even smaller ice crystals that are more uniformly distributed throughout the sample tissue, thus reducing structural damage to food or biochemical samples.

[0004] Currently, both magnetic field and ultrasonic technologies have improved the quality of frozen and refrigerated food to some extent. However, ultrasonic technology consumes a large amount of electrical energy during operation, has a small radiation area, and generates significant noise, making it unsuitable for continuous operation over extended periods. Similarly, applying a magnetic field to a localized area results in uneven magnetic flux distribution, with significant differences in magnetic field strength between the edges and the center. This leads to unstable frozen storage results, and for samples with low water content or low iron content, magnetic field-assisted freezing cannot effectively improve frozen storage quality. Summary of the Invention

[0005] The main objective of this invention is to provide a magnetic field ultrasound-assisted freezing and refrigeration device and its application, thereby overcoming the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: A first aspect of the present invention provides a magnetic field ultrasound-assisted freezing and refrigeration device, comprising: a magnetic field assembly and an ultrasound assembly distributed in a two-dimensional plane, wherein the magnetic field assembly includes m magnetic field generating devices for generating a magnetic field environment, and the ultrasound assembly includes n ultrasound generating devices for generating an ultrasonic environment, wherein at least one of the magnetic field generating devices is disposed between two of the ultrasound generating devices, or at least one of the ultrasound generating devices is disposed between two of the magnetic field generating devices, or at least one of the magnetic field generating devices is surrounded by x of the ultrasound generating devices, or at least one of the ultrasound generating devices is surrounded by y of the magnetic field generating devices, where m, n, x, and y are all positive integers, x≤n, y≤m.

[0007] In a more specific implementation, the ultrasonic component includes five ultrasonic generating devices, four of which are located at the four vertices of a rectangular region, and another ultrasonic generating device is located at the geometric center of the rectangular region. m magnetic field generating devices are distributed in an annular region, which is located within the rectangular region and surrounds the ultrasonic generating device located at the geometric center of the rectangular region. The annular region coincides with the geometric center of the rectangular region.

[0008] In another more specific embodiment, the ultrasonic component includes five ultrasonic generating devices, four of which are located at the four vertices of a rectangular region, and another ultrasonic generating device is located at the geometric center of the rectangular region. An annular magnetic field generating device is distributed in an annular region located within the rectangular region and surrounding the ultrasonic generating device located at the geometric center of the rectangular region. The annular region coincides with the geometric center of the rectangular region.

[0009] In another more specific embodiment, the ultrasound component includes six ultrasound generating devices, which are respectively located at the six vertices of two adjacent rectangular regions, and the magnetic field component includes two magnetic field generating devices, which are respectively located at the geometric center of the two rectangular regions.

[0010] In another more specific implementation, the m magnetic field generating devices included in the magnetic field component and the n ultrasonic generating devices included in the ultrasonic component are arranged in a rectangular array, and the magnetic field generating devices and the ultrasonic generating devices are arranged alternately along the row and column directions of the rectangular array.

[0011] Furthermore, the magnetic field generating device includes an electromagnet or a permanent magnet. It is understood that the m magnetic field generating devices can all be permanent magnets, all be electromagnets, or a combination of electromagnets and permanent magnets. The electromagnet includes a frame and a coil wound on the frame, with the coil electrically connected to a power source. For example, the permanent magnet can be composed of different permanent magnet materials, such as rare-earth permanent magnet materials (neodymium iron boron, samarium cobalt, alnico, etc.), ferrite permanent magnet materials (sintered ferrite, bonded ferrite, etc.), novel permanent magnet materials (rubber soft magnets, etc.), and alloy permanent magnet materials.

[0012] Furthermore, the ultrasonic generating device includes an ultrasonic transducer or a piezoelectric ceramic plate, which is connected to a power source to generate ultrasonic waves. The material of the ultrasonic generating device includes, but is not limited to, ceramics and metals; the shape of the ultrasonic generating device includes, but is not limited to, circular, square, or ring-shaped shapes. Specifically, the frequencies of the n ultrasonic generating devices can be the same or different. It should be noted that due to differences in materials and processing techniques, the impedance and other characteristics of ultrasonic generating devices vary greatly at different frequencies. To achieve the highest transmission efficiency and waveform effect, each ultrasonic generating device is generally matched to only one frequency band based on its resonant fundamental frequency. Furthermore, the operating frequency of the ultrasonic generating device is consistent with the operating frequency of the ultrasonic equipment.

[0013] Furthermore, the magnetic field strength provided by the magnetic field component is 2 mT~300 mT, and the frequency of the ultrasonic wave provided by the ultrasonic component is 20 kHz~100 kHz.

[0014] Furthermore, the excitation voltage of the magnetic field component and the ultrasonic component is 12 V to 200 V, the duty cycle is 1% to 50%, and the waveform of the excitation voltage is a square wave or a sine wave.

[0015] Furthermore, the radial distance between the magnetic field center line of any magnetic field generating device and the ultrasonic center of the adjacent ultrasonic generating device is 0~350 mm. For example, the radial distance can be 0 mm, 50 mm, 80 mm, 85 mm, 100 mm, 110 mm, 130 mm, 138 mm, 150 mm, 175 mm, 180 mm, 183 mm, 205 mm, 220 mm, 300 mm, 350 mm, etc.

[0016] Furthermore, the magnetic field ultrasound-assisted freezing and refrigeration device also includes: a storage tray for holding items, and the magnetic field component and the ultrasound component are fixedly disposed on the back of the storage tray.

[0017] Furthermore, a magnetic field ultrasonic component inlay layer is provided on the back of the tray, and the magnetic field generating device and the ultrasonic generating device are fixedly disposed on the magnetic field ultrasonic component inlay layer. For example, the material of the magnetic field ultrasonic component inlay layer includes, but is not limited to, metallic materials such as stainless steel and alloys.

[0018] A second aspect of the present invention provides a freezing and refrigeration apparatus, comprising: a freezing and refrigeration chamber and the magnetic field ultrasound-assisted freezing and refrigeration device, wherein the magnetic field ultrasound-assisted freezing and refrigeration device is disposed in the freezing and refrigeration chamber.

[0019] A third aspect of this invention provides a method for preserving food and biochemical samples, comprising: Food and biochemical samples are placed in the freezing and refrigeration chamber of the aforementioned freezing and refrigeration device, and the magnetic field ultrasound-assisted freezing and refrigeration device creates a magnetic field environment and an ultrasonic environment in the freezing and refrigeration chamber.

[0020] Compared with the prior art, the advantages of the present invention include: the magnetic field ultrasound-assisted freezing and refrigeration device provided in the embodiments of the present invention can affect the movement state of water molecules, and can be used to improve the ice crystal size during food freezing and storage, reduce freezing mechanical damage, and lower the freezing point and freezing time, etc. Attached Figure Description

[0021] Figure 1 This is a top view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 1 of the present invention; Figure 2 This is a side view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 1 of the present invention; Figure 3 This is a top view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 2 of the present invention; Figure 4 This is a side view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 2 of the present invention; Figure 5 These are the freezing curves of chicken samples from Example 2 and Comparative Example 1 of the present invention; Figure 6 This is a top view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 3 of the present invention; Figure 7 This is a side view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 3 of the present invention; Figure 8 This is a top view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 4 of the present invention; Figure 9 This is a side view of a magnetic field ultrasound-assisted freezing and refrigeration device according to Embodiment 4 of the present invention; Figure 10This is a top view of a magnetic field ultrasound-assisted freezing and refrigeration device in Comparative Example 4; Figure 11 This is a side view of a magnetic field ultrasound-assisted freezing and refrigeration device in Comparative Example 4; Figure 12a , Figure 12b These are, respectively, electron micrographs of frozen sections of shrimp samples from Example 4 and Comparative Example 4 of the present invention. Detailed Implementation

[0022] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0023] The present invention provides a magnetic field ultrasound-assisted freezing and refrigeration device with a specific structure, which has the optimal energy consumption and operating frequency of the ultrasound generator. At the same time, the magnetic field strength and position distribution of the magnetic field generator are correlated with the ultrasound generator, ensuring the effective effect of ultrasound and magnetic field on freezing and refrigeration of food or biochemical samples.

[0024] This invention provides a magnetic field and ultrasound-assisted freezing and refrigeration device that can influence the state of water molecule micelles. It can be used to improve ice crystal size during food freezing and refrigeration, reduce mechanical damage during freezing, and affect freezing point and freezing time. The device includes a magnetic field assembly and an ultrasound assembly distributed in a one- or two-dimensional plane. The magnetic field assembly includes m magnetic field generating devices to generate a magnetic field environment. The ultrasound assembly includes n ultrasound generating devices to generate an ultrasonic environment. At least one of the magnetic field generating devices is positioned between two ultrasound generating devices, or at least one ultrasound generating device is positioned between two magnetic field generating devices, or at least one magnetic field generating device is surrounded by x ultrasound generating devices, or at least one ultrasound generating device is surrounded by y magnetic field generating devices. Here, m, n, x, and y are all positive integers, x ≤ n, and y ≤ m.

[0025] Because the magnetic field lines generated by the magnetic field generator have a significant difference in density between the edge and center regions, with the center region being denser and the edge region sparser, the magnetic field generator is positioned around the ultrasonic generator or arranged in a rectangular array with it. Furthermore, the radial distance between the central magnetic field line of the magnetic field generator and the ultrasonic center of the adjacent ultrasonic generator is less than 350 mm. The inventors of this study discovered that water molecules possess a certain dipole moment and diamagnetism, causing them to orient themselves under magnetic field lines. Due to the constraint of these magnetic field lines, the translational or rotational degrees of freedom of water molecules change. Under excessively dense magnetic field lines, the diffusion path of water molecules may bend, reducing the diffusion rate. However, under the influence of ultrasound, water molecules vibrate and displace strongly, breaking the relatively stable hydrogen bond network structure of water molecules. This helps the water molecules, constrained by excessively dense magnetic field lines, to disperse more evenly. The alignment direction of water molecules guided by the magnetic field, combined with the nucleation sites provided by the ultrasonic cavitation effect, promotes the formation of small, regular ice crystals in a shorter time, reducing the quick-freezing time. However, prolonged ultrasonic treatment causes water molecules to absorb sound energy and convert it into heat energy, resulting in an increase in temperature. Therefore, it is only suitable for short-term intermittent operation. In contrast, the effect of a magnetic field is gentle and has a certain hysteresis. When combined with ultrasound, it can cause the hydrogen bonds that have been broken by ultrasound to recombine and form new hydrogen bonds, thereby changing the hydrogen bond network structure of water molecules to achieve a new equilibrium and thus lowering the freezing point, allowing freezing at a lower temperature.

[0026] The following will further explain the technical solution, its implementation process and principle in conjunction with the accompanying drawings and specific implementation examples. Unless otherwise specified, the ultrasonic transducers, power supplies and other components used in the embodiments of the present invention are known to those skilled in the art and can be obtained commercially.

[0027] Example 1 Please see Figure 1 and Figure 2 A magnetic field and ultrasound-assisted freezing and refrigeration technology device includes a magnetic field component, an ultrasound component, a power supply 103, and a storage tray 104. The back of the storage tray 104 is an inlaid layer of the magnetic field and ultrasound component, which is made of metal materials such as stainless steel and alloys. The magnetic field component and the ultrasound component are fixed on the back of the storage tray 104.

[0028] In this embodiment, the tray 104 is a rectangle of 375 mm × 300 mm. The ultrasonic component includes five φ58 × 67 mm ultrasonic transducers 102, four of which are located at the four vertices of a 270 mm × 215 mm rectangular area, and the other is located at the geometric center of the rectangular area. The five ultrasonic transducers 102 are electrically connected to a power supply 103. The power supply 103 provides an excitation voltage of 125 V with a duty cycle of 1-50%. The waveform of the excitation voltage is a square wave or a sine wave. The frequency of the ultrasonic waves provided by the ultrasonic transducers 102 is adjusted to 20-100 kHz by the power supply 103. The magnetic field component includes eight 40 × 20 × 10 mm permanent magnets 101. The magnetic field strength of the permanent magnets 101 is 10-100 mT. The eight permanent magnets 101 are evenly distributed at intervals in a region with an inner diameter of 140 mm and an outer diameter of 180 mm. A circular annular region, mm in diameter, is located within the rectangular region and surrounds the ultrasonic transducer 102 located at the geometric center of the rectangular region. The geometric center of the circular annular region coincides with that of the rectangular region. Permanent magnets 101 are placed around the ultrasonic transducer 102 in a certain arrangement. The radial distance between the magnetic field center line generated by any permanent magnet 101 and the ultrasonic center generated by the adjacent ultrasonic transducer 102 is 80~138 mm.

[0029] Specifically, the power supply 103 includes a circuit board and a PLC control system, etc. The numerical control program used by the power supply 103 can be obtained commercially. Furthermore, the circuit structure in this invention is implemented using methods or techniques known to those skilled in the art, and no special limitations are made here.

[0030] Example 2 Chicken frozen and refrigerated This embodiment uses a magnetic field ultrasound-assisted freezing and refrigeration technology device to assist in the freezing and refrigeration of chicken. The magnetic field ultrasound-assisted freezing and refrigeration technology device used in this embodiment has the same overall structure as the magnetic field ultrasound-assisted freezing and refrigeration technology device in Embodiment 1, and the similar parts will not be described again here.

[0031] The magnetic field ultrasound-assisted freezing and refrigeration technology device used in this embodiment is as follows: Figure 3 and Figure 4 As shown.

[0032] In this embodiment, the storage tray 204 is a rectangle of 400 mm × 220 mm. The ultrasonic component includes five φ50 × 2.6 mm circular piezoelectric ceramic plates 202 with flanged electrodes. Four of the piezoelectric ceramic plates 202 are located at the four vertices of a 325 mm × 150 mm rectangular area, and the other piezoelectric ceramic plate 202 is located at the geometric center of the rectangular area. The five piezoelectric ceramic plates 202 are electrically connected to a power supply 203. The power supply 203 provides the piezoelectric ceramic plates 202 with an excitation voltage of 100 V, a duty cycle of 3%, and a square wave excitation waveform. The ultrasonic frequency is controlled to 40 kHz by the power supply 203. The magnetic field component includes an electromagnet 201, which includes a hollow frame skeleton and a coil wound on the hollow frame skeleton. The inner frame size of the hollow frame skeleton is 150 mm × 70 mm, the outer frame size is 255 mm × 150 mm, and the coil is 0.5 mm long. The coil is made of 300 turns of copper wire (mm²). It is electrically connected to power supply 203. Power supply 203 provides the coil with an excitation voltage of 24 V, a duty cycle of 30%, and a square wave excitation waveform. The power supply 203 controls the central magnetic field strength of electromagnet 201 to 5 mT. The radial distance between the central magnetic field lines generated by electromagnet 201 and the ultrasonic center generated by the adjacent piezoelectric ceramic sheet 202 is 0 or 180 mm.

[0033] A tray 204 equipped with a magnetic field component and an ultrasonic component was placed in a freezer-freezer, with the freezer-freezer temperature set to -20 ℃. Temperature changes during the freezing process were measured. The results showed that in the initial freezing stage, the time required for the temperature to drop to -1 ℃ was 18 min, with a freezing rate of 0.89 ℃ / min and a freezing phase transition time of 32 min. The time required to freeze from -1 ℃ to -20 ℃ was 75 min, with a freezing rate of 0.25 ℃ / min.

[0034] Comparative Example 1 Chicken frozen and refrigerated Comparative Example 1 is basically the same as Example 2, except that the magnetic field strength of the electromagnet used in this comparative example is 0.5 mT, the ultrasonic frequency is 40 kHz, and the duty cycle is 0.5%.

[0035] Monitoring revealed that during the initial freezing phase, the time required for the chicken temperature to drop to -1℃ was 25 min, the freezing rate was 0.64℃ / min, and the freezing phase change time was 54 min. The time required to freeze from -1℃ to -20℃ was 76 min, and the freezing rate was 0.25℃ / min.

[0036] Please see Figure 5 , Figure 5These are the freezing curves of chicken samples from Example 2 and Comparative Example 1 of this invention. It can be seen that during the freezing process of chicken in Example 2, under the appropriate magnetic field strength and ultrasonic assistance, water molecules align and orient themselves along the magnetic field lines. Furthermore, in areas with dense magnetic field lines, water molecules vibrate and shift under the influence of ultrasound, breaking the constraint of the magnetic field lines on the water molecules in the local area. This causes water molecules to disperse, forming smaller ice crystals, reducing the freezing phase transition time, and increasing the freezing rate. In contrast, the magnetic field strength provided in Comparative Example 1 is relatively low, resulting in weak constraint of the magnetic field lines on the water molecules. This reduces the effective alignment and orientation of the water molecules. Additionally, the ultrasonic duty cycle is too low, and the action time is too short, leading to insufficient nucleation interference, which in turn results in the formation of irregular large ice crystals and low freezing efficiency.

[0037] Example 3 frozen beef This embodiment uses a magnetic field ultrasound-assisted freezing and refrigeration technology device to assist in the freezing and refrigeration of beef. The overall structure of the magnetic field ultrasound-assisted freezing and refrigeration technology device used in this embodiment is the same as that in Embodiment 1, and the similar parts will not be described again here.

[0038] The magnetic field ultrasound-assisted freezing and refrigeration technology device used in this embodiment is as follows: Figure 6 and Figure 7 As shown.

[0039] In this embodiment, the tray 304 is a rectangle of 380 mm × 250 mm. The ultrasonic component includes three φ40 × 3 mm circular piezoelectric ceramic plates 302 (1) with flanged electrodes, and three φ58 × 67 mm ultrasonic transducers 302 (2). The three piezoelectric ceramic plates 302 (1) and the three ultrasonic transducers 302 (2) are located at the four vertices of two adjacent rectangular regions. Both rectangular regions are 145 mm × 168 mm. In the short side direction of the rectangular regions, the piezoelectric ceramic plates 302 (1) and the ultrasonic transducers 302 (2) are spaced apart. The piezoelectric ceramic plates 302 (1) and the ultrasonic transducers 302 (2) are electrically connected to the power supply 303. The power supply 303 provides an excitation voltage of 150 kV to the piezoelectric ceramic plates 302 (1) and the ultrasonic transducers 302 (2). With a duty cycle of 2% and an excitation waveform of square wave, the ultrasonic frequencies of the piezoelectric ceramic plate 302(1) and ultrasonic transducer 302(2) are adjusted by power supply 303 to be 40 kHz and 28 kHz, respectively. The magnetic field assembly includes two φ80×10 mm permanent magnets 301, which are located at the geometric centers of the two rectangular regions where the ultrasonic assembly is located. The radial distance between the two permanent magnets 301 is 145 mm, the magnetic field strength at the surface center of the permanent magnet 301 is 100 mT, and the radial distance between the magnetic field center lines generated by the permanent magnet 301 and the ultrasonic center generated by the adjacent piezoelectric ceramic plate / ultrasonic transducer is 110 mm.

[0040] A tray 304 equipped with a magnetic field component and an ultrasonic component was placed in a freezer-freezer, with the freezer temperature set to -20 ℃. 500 g of beef was cut into 2 cm thick slices and placed in the tray. After freezing for 2 hours, the beef was thawed at room temperature. The thawing water loss rate was calculated as: Thawing water loss rate = (1 - mass of thawed sample / mass of sample before thawing) × 100%. The final thawing water loss rate was 1.23%.

[0041] Comparative Example 2 Frozen or refrigerated beef Cut 500 g of beef into 2 cm thick slices and place them directly in a freezer. Set the freezer temperature to -20 ℃ and freeze for 2 hours. Then thaw at room temperature and calculate the thawing water loss rate. Thawing water loss rate = (1 - mass of sample after thawing / mass of sample before thawing) × 100%. The final thawing water loss rate was 6.73%.

[0042] Comparative Example 3 Frozen or refrigerated beef Comparative Example 3 is basically the same as Example 3, except that: the surface magnetic field strength of the permanent magnet used in this comparative example is 500 mT, the ultrasonic frequency is 40 kHz, the duty cycle is 60%, and the thawing water loss rate of the beef after freezing and thawing is 4.67%.

[0043] Studies on the freezing treatment of Example 3, Comparative Examples 2 and 3 revealed that during the freezing of beef using a magnetic field ultrasound-assisted freezing and refrigeration device, water molecules formed small ice crystals under appropriate magnetic field strength and ultrasonic assistance, resulting in minimal water loss after thawing. In Comparative Example 2, the beef was directly frozen at low temperatures under conventional freezing conditions, leading to significant water loss after thawing, possibly due to the formation of irregular, large ice crystals. In Comparative Example 3, a higher magnetic field strength constrained water molecules, reducing their diffusion rate and causing the formation of larger ice crystals in situ. Simultaneously, the high ultrasonic duty cycle and prolonged ultrasonic treatment caused water molecule micelles to absorb acoustic energy and convert it into heat energy. This spurred continuous recrystallization of the ice crystals during freezing, ultimately forming larger ice crystals. Upon thawing, these ice crystals damaged the beef cell structure, causing water loss.

[0044] Example 4 Shrimp frozen and refrigerated This embodiment uses a magnetic field ultrasound-assisted freezing and refrigeration technology device to assist in the freezing and refrigeration of shrimp. The overall structure of the magnetic field ultrasound-assisted freezing and refrigeration technology device used in this embodiment is the same as that in Embodiment 1, and the similar parts will not be described again here.

[0045] The magnetic field ultrasound-assisted freezing and refrigeration technology device used in this embodiment is as follows: Figure 8 and Figure 9 As shown.

[0046] In this embodiment, the tray 404 is a rectangle of 680 mm × 500 mm. The ultrasonic component includes six circular piezoelectric ceramic plates 402 with a diameter of 50 × 2.6 mm and flanged electrodes. The magnetic field component includes six permanent magnets 401 with a diameter of 75 × 10 mm. The six permanent magnets 401 and the six piezoelectric ceramic plates 402 are arranged in a rectangular array. The permanent magnets 401 and piezoelectric ceramic plates 402 are alternately arranged in both the row and column directions of the rectangular array. The row spacing of the permanent magnets 401 and the piezoelectric ceramic plates 402 is 183 mm, and the column spacing is 180 mm. The piezoelectric ceramic plates 402 are electrically connected to a power supply 403. The power supply 403 provides the piezoelectric ceramic plates 402 with an excitation voltage of 175 V, a duty cycle of 5%, and a sine wave excitation waveform. The ultrasonic frequency is adjusted to 40 kHz by the power supply 403, and the magnetic field strength at the center of the surface of the permanent magnet 401 is 50. The radial distance between the magnetic field center lines generated by the permanent magnet 401 and the ultrasonic center of the adjacent piezoelectric ceramic sheet 402 is 180 or 183 mm.

[0047] A tray 404 equipped with ultrasonic and magnetic field components was placed in a freezer-freezer, with the freezer temperature set to -18 ℃. The microstructure of the frozen shrimp samples was observed after sectioning. Figure 12a As shown.

[0048] Comparative Example 4 Shrimp frozen and refrigerated Comparative Example 4 is basically the same as Example 4, except that: the magnetic field ultrasonic-assisted freezing and refrigeration technology device used in Comparative Example 4 is as follows: Figure 10 and Figure 11 As shown, in the comparative example, six permanent magnets 501 and six piezoelectric ceramic sheets 502 are arranged in sections. The row spacing of the six piezoelectric ceramic sheets 502 is 183 mm, and the column spacing is 180 mm. The row spacing of the six permanent magnets 501 is 183 mm, and the column spacing is 180 mm. The radial distance between the magnetic field lines at the center of the magnetic field generated by the permanent magnets and the ultrasonic centers of the adjacent piezoelectric ceramic sheets is 183–4408 mm. The microstructure of frozen shrimp samples was observed after slicing. Figure 12b As shown.

[0049] Tests revealed that, under suitable magnetic field strength and ultrasonic assistance, the positional distribution of the magnetic field generator and the ultrasonic generator maintained a certain correlation. In Example 4, during the shrimp freezing process, the magnetic field guided the formation of tiny ice crystals at the nucleation sites generated by the ultrasound, resulting in minimal mechanical damage to the cells. Figure 12a The central tissue cells have clear edges and a dense structure. In contrast, in Comparative Example 4, the magnetic field and ultrasound are arranged in zones, with the radial distance between the magnetic field center lines of the peripheral permanent magnets and the adjacent ultrasound centers reaching a maximum of 408 mm. Therefore, these magnetic field lines act separately on the tissue cells of the sample, leading to the formation of irregular large ice crystals that damage the cell tissue, and even localized overheating. Figure 12b The cellular structure is damaged.

[0050] It should be noted that the foregoing embodiments are merely illustrative examples of the present invention, and the various process conditions used are typical examples. However, after extensive testing and verification by the inventors of this case, the other process conditions listed above are also applicable and can achieve the technical effects claimed by the present invention.

[0051] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A magnetic field ultrasound-assisted freezing and refrigeration device, characterized in that, include: A magnetic field component and an ultrasonic component are distributed in a one- or two-dimensional plane. The magnetic field component includes m magnetic field generating devices for generating a magnetic field environment. The ultrasonic component includes n ultrasonic generating devices for generating an ultrasonic environment. At least one of the magnetic field generating devices is disposed between two ultrasonic generating devices, or at least one ultrasonic generating device is disposed between two magnetic field generating devices, or at least one magnetic field generating device is surrounded by x ultrasonic generating devices, or at least one ultrasonic generating device is surrounded by y magnetic field generating devices, where m, n, x, and y are all positive integers, x ≤ n, and y ≤ m.

2. The magnetic field ultrasonic-assisted freezing and refrigeration device according to claim 1, characterized in that: The ultrasonic component includes five ultrasonic generating devices, four of which are located at the four vertices of a rectangular region, and the other ultrasonic generating device is located at the geometric center of the rectangular region. m magnetic field generating devices are distributed in an annular region, which is located within the rectangular region and surrounds the ultrasonic generating device located at the geometric center of the rectangular region. The annular region coincides with the geometric center of the rectangular region.

3. The magnetic field ultrasonic-assisted freezing and refrigeration device according to claim 1, characterized in that: The ultrasonic component includes five ultrasonic generating devices, four of which are located at the four vertices of a rectangular region, and another ultrasonic generating device is located at the geometric center of the rectangular region. An annular magnetic field generating device is distributed within an annular region, which is located within the rectangular region and surrounds the ultrasonic generating device located at the geometric center of the rectangular region. The annular region coincides with the geometric center of the rectangular region.

4. The magnetic field ultrasound-assisted freezing and refrigeration device according to claim 1, characterized in that: The ultrasound component includes six ultrasound generators, which are located at the six vertices of two adjacent rectangular regions. The magnetic field component includes two magnetic field generators, which are located at the geometric centers of the two rectangular regions.

5. The magnetic field ultrasonic-assisted freezing and refrigeration device according to claim 1, characterized in that: The magnetic field component contains m magnetic field generating devices and the ultrasonic component contains n ultrasonic generating devices, which are arranged in a rectangular array. The magnetic field generating devices and the ultrasonic generating devices are arranged alternately along the row and column directions of the rectangular array.

6. The magnetic field ultrasonic-assisted freezing and refrigeration device according to any one of claims 1-5, characterized in that: The radial distance between the central magnetic field line of the magnetic field generated by any of the magnetic field generating devices and the center of the ultrasound generated by the adjacent ultrasonic generating devices is 0 mm to 350 mm. Preferably, the magnetic field generating device includes an electromagnet or a permanent magnet, and the ultrasonic generating device includes an ultrasonic transducer or a piezoelectric ceramic sheet.

7. The magnetic field ultrasonic-assisted freezing and refrigeration device according to any one of claims 1-5, characterized in that: The magnetic field strength provided by the magnetic field component is 2 mT~300 mT, and the frequency of the ultrasonic waves provided by the ultrasonic component is 20 kHz~100 kHz.

8. The magnetic field ultrasonic-assisted freezing and refrigeration device according to any one of claims 1-5, characterized in that, Also includes: A storage tray for holding items, wherein the magnetic field component and the ultrasonic component are fixedly mounted on the back of the storage tray.

9. A freezing and refrigeration apparatus, characterized in that, include: The freezing and refrigeration chamber and the magnetic field ultrasound-assisted freezing and refrigeration device according to any one of claims 1-8, wherein the magnetic field ultrasound-assisted freezing and refrigeration device is disposed in the freezing and refrigeration chamber.

10. A method for preserving food and biochemical samples, characterized in that, include: Food and biochemical samples are placed in the freezing and refrigeration chamber of the freezing and refrigeration device according to claim 9, and the magnetic field ultrasound-assisted freezing and refrigeration device forms a magnetic field environment and an ultrasonic environment in the freezing and refrigeration chamber.

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