Anti-frosting partition independent temperature control water product freezing device and freezing method

Abstract

The present application relates to the field of refrigeration equipment and food freezing technology, in particular to a frost-proof partition independent temperature control aquatic product freezing device and freezing method; comprising upper and lower freezing cavities separated by heat preservation partitions, a front cold trap, an evaporator coil, a centrifugal fan, branch air ducts, a flow interception assembly and an industrial computer module; the device collects temperature data of each freezing cavity in real time through thermocouples; the core is that the industrial computer calculates the cooling rate and cooling capacity demand weight according to the temperature data, dynamically controls the servo motor to adjust the opening angle of the upper and lower interception baffles, and realizes accurate distribution of cold air in proportion; the present application realizes accurate partition independent temperature control of different aquatic products by accurate flow guiding of cold air output by a single fan without increasing multiple sets of refrigerant circuits, effectively reducing system hardware redundancy and operation energy consumption.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment and food freezing technology, specifically to a freezing device and method for aquatic products with independent temperature control and anti-frost zones. Background Technology

[0002] In current aquatic product freezing processing scenarios, freezing equipment needs to simultaneously handle aquatic products with different freezing depths and surface cooling rates. Meanwhile, the high-humidity return air generated within the freezing chamber easily frosts quickly on the evaporator coil surface as it flows through the cold source. To meet these temperature control and defrosting requirements, existing solutions generally employ multiple independent refrigerant circuits to achieve zoned cooling, using a shutdown-based electric defrosting architecture. This involves periodically interrupting the cooling process through scheduling and control, activating an electric heating device to melt the frost on the evaporator surface. While this solution offers some zoned processing and defrosting capabilities, its high dependence on complex refrigeration circuits and shutdown heating mechanisms results in system hardware redundancy and high energy consumption. Furthermore, frost buildup on the evaporator can easily clog the fin channels, leading to reduced airflow. Additionally, the shutdown defrosting process inevitably introduces heat into the freezing chamber, causing a sudden rise in the freezing environment temperature and disrupting the continuous freezing curve of the aquatic products.

[0003] Therefore, how to achieve precise independent temperature control in different zones without adding multiple refrigerant circuits, and how to achieve priority defrosting and efficient physical defrosting during continuous cooling to maintain stable cavity temperature, has become an urgent technical problem to be solved. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a freezing device and method for freezing aquatic products with independent temperature control in anti-frost zones. Specifically, the technical solution of the present invention is as follows:

[0005] The anti-frost, zoned, independently temperature-controlled aquatic product freezing unit includes:

[0006] The insulated box has a horizontally placed polyurethane insulation partition inside, which divides the insulated box into an upper freezing chamber equipped with an upper thermocouple and a lower freezing chamber equipped with a lower thermocouple.

[0007] Evaporator coils are located inside the insulated box;

[0008] A front-mounted cold trap is located in front of the air inlet side of the evaporator coil, including a windward baffle and an inclined water guide plate below it. The windward baffle is connected to a stepper motor, and a front static pressure pipe and a rear static pressure pipe are respectively provided on its two sides.

[0009] A centrifugal fan is connected to the air outlet side of the evaporator coil, and its outlet is connected to the main air duct. The main air duct is divided into an upper branch air duct and a lower branch air duct that respectively connect the upper freezing chamber and the lower freezing chamber.

[0010] The flow interception assembly includes an upper flow interception baffle and a lower flow interception baffle. The upper flow interception baffle is hinged to the inlet of the upper branch air duct and connected to a first servo motor. The lower flow interception baffle is hinged to the inlet of the lower branch air duct and connected to a second servo motor.

[0011] The industrial control computer is electrically connected to the stepper motor, centrifugal fan, first servo motor, second servo motor, upper thermocouple, lower thermocouple, front static pressure tube, and rear static pressure tube.

[0012] In a preferred embodiment, a support frame is provided on the bottom surface of the interior of the heat insulation box, and the evaporator coil is fixed on the support frame, wherein the evaporator coil is a copper tube with aluminum fins.

[0013] In a preferred embodiment, the windward water deflector is an aluminum alloy plate, wherein the surface of the windward water deflector is machined with longitudinal guide grooves, both ends of the windward water deflector are mounted to the side wall of the heat insulation box through rotating bearings, the rotating shaft of the driving end of the windward water deflector is directly connected to the stepper motor through a coupling, and the stepper motor is fixed to the outer wall of the heat insulation box.

[0014] In a preferred embodiment, the air outlet of the upper freezing chamber is connected to the upper return air duct, and the air outlet of the lower freezing chamber is connected to the lower return air duct, wherein the upper return air duct and the lower return air duct converge and face the windward side of the windward baffle.

[0015] In a preferred embodiment, the front static pressure pipe is fixed directly in front of the windward side of the windward water deflector, and the rear static pressure pipe is fixed directly behind the leeward side of the windward water deflector.

[0016] In a preferred embodiment, the upper thermocouple is fixed to the side wall of the upper freezing chamber, and the lower thermocouple is fixed to the side wall of the lower freezing chamber.

[0017] In a preferred embodiment, the lowest end of the inclined water guide plate is connected to a drain pipe, wherein the drain pipe extends out of the heat insulation box.

[0018] Anti-frost zone independent temperature control freezing methods include:

[0019] S1. The industrial control computer reads the temperature data of the upper thermocouple and the lower thermocouple in real time, and calculates the cooling rate of the aquatic products in the upper freezing chamber and the lower freezing chamber.

[0020] S2. The industrial control computer evaluates the lag state of the actual cooling process of each freezing chamber according to the preset target cooling curve, and determines the weight of the cooling demand based on the relative proportion of the lag state of the two chambers.

[0021] S3. The industrial control computer sends control commands to the first servo motor and the second servo motor according to the cooling demand weight, adjusts the opening angle of the upper baffle and the lower baffle, and distributes the cold air blown out by the centrifugal fan in proportion.

[0022] S4. The industrial control computer reads the static pressure values ​​collected by the front static pressure pipe and the rear static pressure pipe in real time, calculates the wind pressure difference on both sides of the windward water baffle, and calculates the equivalent frost layer thickness.

[0023] S5. The industrial control computer determines whether the equivalent frost layer thickness has reached a preset critical value. If it has reached the preset critical value, it executes step S6; if it has not reached the preset critical value, it returns to execute step S1.

[0024] S6. The industrial control computer controls the stepper motor to rotate, adjusts the tilt angle of the windward baffle to be parallel to the airflow direction, and at the same time controls the speed of the centrifugal fan to increase to the preset overclocking speed. According to the ratio of air pressure increase before and after the centrifugal fan speed increase, the industrial control computer controls the first servo motor and the second servo motor to synchronously reduce the opening angle of the upper baffle and the lower baffle to the corresponding target compensation opening, so as to maintain the stability of the air volume entering each freezing chamber.

[0025] S7. After maintaining the preset defrosting time, the industrial control computer controls the stepper motor to restore the windward water deflector to its original tilt angle and controls the centrifugal fan to restore its original speed, then returns to step S1.

[0026] In a preferred embodiment, the calculation of the equivalent frost layer thickness in step S4 includes: the industrial control computer obtaining the wind pressure difference increment based on the current wind pressure difference and the preset frost-free initial wind pressure difference; and evaluating and obtaining the equivalent frost layer thickness based on the resistance conversion relationship corresponding to the current tilt angle of the windward water deflector.

[0027] In a preferred embodiment, in step S6, the preset overclocking speed is a preset multiple of the rated speed, and the industrial control computer controls the speed of the centrifugal fan to increase to the preset overclocking speed within a preset acceleration time.

[0028] The present invention has the following beneficial effects:

[0029] 1. This invention uses a polyurethane insulation partition to divide the insulated box into an upper freezing chamber and a lower freezing chamber, and sets flow-blocking baffles driven by servo motors at the inlets of the upper and lower branch air ducts respectively; the industrial control computer calculates the cooling rate and cooling capacity demand weight of the two chambers based on real-time temperature data collected by thermocouples, and then dynamically adjusts the opening angle of the flow-blocking baffles; this design accurately distributes the cold air output from the same centrifugal fan proportionally without adding multiple sets of refrigerant circuits, realizing precise independent temperature control of aquatic products with different freezing requirements, effectively reducing system hardware redundancy and operating energy consumption;

[0030] 2. This invention features a pre-cold trap with a windward baffle plate positioned in front of the evaporator coil's air inlet side. This actively intercepts frost condensed from the high-humidity return air, preventing blockage of the coil channels. The industrial control computer calculates the equivalent frost thickness based on the air pressure difference collected by the static pressure pipe. When defrosting is required, it controls a stepper motor to adjust the windward baffle plate to be parallel to the airflow and increases the centrifugal fan speed for physical and pneumatic defrosting. Simultaneously, it reduces the opening angle of the baffle plate to stabilize the airflow. This method replaces the traditional shutdown-based electric defrosting, achieving efficient defrosting under continuous refrigeration conditions and avoiding the introduction of heat during defrosting that could disrupt the continuous freezing curve of aquatic products. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall external right side structure of the device;

[0032] Figure 2 This is a schematic diagram of the overall external left side structure of the device;

[0033] Figure 3 This is a cross-sectional structural diagram of the insulated box.

[0034] Figure 4 This is a schematic diagram of the front-mounted cold trap.

[0035] Figure 5 This is a schematic diagram of the flow interception component;

[0036] Figure 6 This is a schematic diagram of the evaporator coil structure;

[0037] Figure 7 This is a flowchart of the method of the present invention.

[0038] In the diagram: 1. Anti-frost zoned independent temperature-controlled aquatic product freezing device; 2. Insulated box; 3. Polyurethane insulation partition; 4. Upper freezing chamber; 5. Lower freezing chamber; 8. Evaporator coil; 9. Pre-cold trap; 10. Windward water baffle; 11. Inclined water guide plate; 12. Stepper motor; 13. Front static pressure pipe; 14. Rear static pressure pipe; 15. Centrifugal fan; 16. Main air duct; 17. Upper branch air duct; 18. Lower branch air duct; 19. Flow interception assembly; 20. Upper flow interception baffle; 21. Lower flow interception baffle; 22. First servo motor; 23. Second servo motor; 24. Industrial control computer; 25. Support frame; 26. Longitudinal guide groove; 27. Rotary bearing; 28. Coupling; 29. ​​Upper return air duct; 30. Lower return air duct; 31. Drain pipe. Detailed Implementation

[0039] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0040] Example 1:

[0041] The anti-frost, zoned, independently temperature-controlled aquatic product freezing unit includes:

[0042] The insulated box 2 is equipped with a horizontally placed polyurethane insulation partition 3, which divides the insulated box 2 into an upper freezing chamber 4 equipped with an upper thermocouple and a lower freezing chamber 5 equipped with a lower thermocouple.

[0043] Combination Figure 6 As shown, the evaporator coil 8 is installed inside the insulated box 2;

[0044] Combination Figure 4 As shown, the front cold trap 9 is located in front of the air inlet side of the evaporator coil 8, including a windward baffle 10 and an inclined water guide plate 11 located below it. The windward baffle 10 is connected to a stepper motor 12, and a front static pressure pipe 13 and a rear static pressure pipe 14 are respectively provided on its two sides.

[0045] Combination Figure 1 and Figure 2 As shown, the centrifugal fan 15 is connected to the air outlet side of the evaporator coil 8, and its outlet is connected to the main air duct 16. The main air duct 16 is divided into an upper branch air duct 17 and a lower branch air duct 18 that connect the upper freezing chamber 4 and the lower freezing chamber 5 respectively.

[0046] Combination Figure 5As shown, the flow interception assembly 19 includes an upper flow interception baffle 20 and a lower flow interception baffle 21. The upper flow interception baffle 20 is hinged to the inlet of the upper branch air duct 17 and connected to the first servo motor 22. The lower flow interception baffle 21 is hinged to the inlet of the lower branch air duct 18 and connected to the second servo motor 23.

[0047] The industrial computer 24 is electrically connected to the stepper motor 12, the centrifugal fan 15, the first servo motor 22, the second servo motor 23, the upper thermocouple, the lower thermocouple, the front static pressure tube 13, and the rear static pressure tube 14.

[0048] The insulated box 2 is made of double-layer stainless steel plate with a middle rigid foam insulation layer. The inner wall of the box is made of food-grade low-temperature resistant material, which makes it easy to maintain the stable temperature inside the box under the continuous feeding and unloading of aquatic products. The purpose of setting the polyurethane insulation partition 3 is to distribute the cold capacity corresponding to the same main cold source into two independently adjustable freezing spaces. The upper freezing chamber 4 is used to place aquatic products that need to reach the first set freezing depth, and the lower freezing chamber 5 is used to place aquatic products that need to reach the second set surface freezing rate.

[0049] The upper and lower thermocouples collect temperature data of representative locations in the two freezing chambers respectively. The thermocouples can adopt a K-type armored structure, and the temperature measurement range can be set from -50℃ to 20℃. The sampling period can be set from 1s to 5s. The evaporator coil 8 is arranged after the return air confluence area inside the heat insulation box 2, so that the return air passes through the pre-cold trap 9 before entering the evaporator coil 8.

[0050] The windward baffle 10 in the front cold trap 9 is a priority frosting component. It is located in front of the evaporator coil 8 and is used to actively receive the frost that precipitates in the high humidity return air. The inclined water guide plate 11 is located below the windward baffle 10 and is used to receive the water formed by the melting of the blown-down frost and discharge it outside the box. The front static pressure pipe 13 and the rear static pressure pipe 14 respectively collect the static pressure on the front and rear sides of the windward baffle 10 so that the industrial control computer 24 can calculate the wind pressure difference.

[0051] Centrifugal fan 15 is installed on the air outlet side of evaporator coil 8, and its outlet is connected to main air duct 16. Main air duct 16 is further divided into upper branch air duct 17 and lower branch air duct 18, so that the cold air output from the same evaporator coil 8 enters the upper freezing chamber 4 and the lower freezing chamber 5 respectively. Upper baffle 20 and lower baffle 21 are located at the inlet of the two branch air ducts respectively. The opening degree is changed by the first servo motor 22 and the second servo motor 23 to adjust the air intake of the two zones.

[0052] After receiving temperature and static pressure data, the industrial control computer 24 outputs control commands for the stepper motor 12, centrifugal fan 15, and two servo motors, enabling the system to achieve zoned cooling, frost layer determination, and physical defrosting in coordination without adding multiple refrigerant circuits. Compared to equipment that relies solely on shutdown for electric defrosting, this reduces the impact of the defrosting process on the freezing curve inside the cavity.

[0053] A support frame 25 is installed on the bottom surface of the interior of the heat insulation box 2, and the evaporator coil 8 is fixed on the support frame 25. The evaporator coil 8 is a copper tube and aluminum fin structure.

[0054] A support frame 25 is installed on the bottom surface of the insulated box 2 to support the evaporator coil 8 and form a stable installation reference at the bottom of the box. The support frame 25 can be made of stainless steel profiles welded into a frame structure or a bolted assembly structure. A drainage and cleaning space is reserved between the support frame 25 and the bottom surface of the box to prevent ice accumulation at the bottom from affecting equipment maintenance after long-term low-temperature operation. When the evaporator coil 8 is fixed to the support frame 25, it can be fixed by bolts and pressure plates for easy subsequent disassembly and assembly.

[0055] The evaporator coil 8 adopts a copper tube and aluminum fin structure. The outer diameter of the copper tube can be 9.52mm or 12.7mm, and the fin spacing can be 2.5mm to 4mm. The technical consideration for adopting this structure is that the copper tube is convenient for refrigerant heat exchange and bending, and the aluminum fins are conducive to expanding the heat exchange area. At the same time, since the present invention sets a front cold trap 9 on the front side of the evaporator coil 8, the evaporator coil 8 is not a priority frosting component, and the fin spacing can be conventionally designed according to the heat exchange capacity, without having to rely solely on increasing the fin spacing to delay blockage.

[0056] The support frame 25 keeps the evaporator coil 8 at a set height from the bottom of the casing. The return air enters the windward side of the evaporator coil 8 after being treated by the pre-cooling trap 9. The cooled air after heat exchange is then sent into the main air duct 16 by the centrifugal fan 15, thereby maintaining a clear air circulation route.

[0057] Combination Figure 3 and Figure 4 As shown, the windward water deflector 10 is an aluminum alloy plate. The surface of the windward water deflector 10 is machined with longitudinal guide grooves 26. Both ends of the windward water deflector 10 are installed on the side wall of the heat insulation box 2 through rotating bearings 27. The rotating shaft of the driving end of the windward water deflector 10 is directly connected to the stepper motor 12 through the coupling 28. The stepper motor 12 is fixed to the outer wall of the heat insulation box 2.

[0058] The windward water deflector 10 is made of aluminum alloy plate, and the plate thickness can be 2mm to 5mm. The reason for choosing aluminum alloy is that it has a high thermal conductivity, and water vapor in the return air is easy to form frost after contacting the plate surface. At the same time, the material has low density, which is conducive to the stepper motor 12 to perform rapid cornering action.

[0059] The longitudinal guide grooves 26 on the surface of the windward water baffle 10 extend along the height direction of the plate surface. The groove depth can be 1mm to 3mm and the groove spacing can be 5mm to 15mm. The function of the longitudinal guide grooves 26 in this invention is not only to guide liquid, but also to increase the local turbulence and adhesion area on the plate surface, so that the high humidity return air is decelerated on the front side of the windward water baffle 10 and it is easier to precipitate frost. The two ends of the windward water baffle 10 are installed on the side wall of the heat insulation box 2 through rotating bearings 27. The bearings can be low temperature sealed bearings to ensure that they can be rotated repeatedly in an environment below -30℃.

[0060] The drive shaft of the windshield 10 is directly connected to the output shaft of the stepper motor 12 via a coupling 28. The coupling 28 can be a diaphragm type or a plum blossom type structure to compensate for installation coaxiality deviation. The stepper motor 12 is set on the outer wall of the heat insulation box 2 in order to avoid the motor being exposed to high humidity and low temperature space for a long time, which would lead to a decrease in insulation performance.

[0061] This arrangement allows the windward deflector 10 to rotate within a set angle range, for example, maintaining an inclination angle of 20° to 60° under normal frosting conditions, and adjusting it to a range of 0° to 5° that is basically parallel to the airflow direction under frost blowing conditions. This changes the windward projected area and the stress state of the frost layer, providing a structural basis for subsequent pneumatic frost blowing.

[0062] The air outlet of the upper freezing chamber 4 is connected to the upper return air duct 29, and the air outlet of the lower freezing chamber 5 is connected to the lower return air duct 30. The upper return air duct 29 and the lower return air duct 30 are connected to the windward side of the windward baffle plate 10 after they merge.

[0063] The air outlet of the upper freezing chamber 4 is connected to the upper return air duct 29, and the air outlet of the lower freezing chamber 5 is connected to the lower return air duct 30. The two return air ducts converge near the front cold trap 9, and the main direction of the return air after the convergence is directly facing the windward side of the windward baffle plate 10. The return air duct can adopt a plate-type air duct structure, and its cross-sectional area is designed according to the air volume of the centrifugal fan 15. Based on the rated circulating air volume of the upper freezing chamber 4 and the lower freezing chamber 5, the average return air velocity can be maintained at 4m / s to 10m / s.

[0064] The reason for directly directing the return air to the windward baffle plate 10 after converging is that water vapor and ice crystal particles in the high-humidity return air will preferentially deposit here due to changes in flow rate and temperature gradient, forming a separate frost zone in front of the evaporator coil 8. Compared with directing the return air directly to the evaporator coil 8, this arrangement shifts the focus of frost formation from the fin surface to the surface of the windward baffle plate 10, slowing down the rate of blockage in the channels between the fins of the evaporator coil 8.

[0065] The confluence section of the upper return air duct 29 and the lower return air duct 30 can be equipped with a flow guide transition angle, which can be 30° to 60°, to reduce the local eddy current loss during the confluence and ensure that the airflow impacts the windward baffle 10 evenly after the confluence. This arrangement also makes the pressure changes measured by the front static pressure pipe 13 and the rear static pressure pipe 14 mainly reflect the resistance changes caused by the frost on the windward baffle 10, which is convenient for the industrial control computer 24 to perform frost layer state inversion.

[0066] The front static pressure pipe 13 is fixed to the front of the windward side of the windward water baffle 10, and the rear static pressure pipe 14 is fixed to the rear of the leeward side of the windward water baffle 10.

[0067] The front static pressure tube 13 is fixed in front of the windward side of the windward baffle 10, and the rear static pressure tube 14 is fixed behind the leeward side of the windward baffle 10. Both are used to collect the static pressure value of the airflow before and after passing through the windward baffle 10. The static pressure tube can be a stainless steel capillary tube or a low-temperature resistant polymer pressure-conducting tube. Its pressure tapping hole can be set with multiple circumferentially distributed micropores to reduce the sampling fluctuation caused by the flow direction deviation.

[0068] The distance between the front static pressure pipe 13 and the windward baffle 10 can be 10mm to 50mm, and the distance between the rear static pressure pipe 14 and the windward baffle 10 can also be 10mm to 50mm. The pressure tapping position avoids the influence area of ​​the rotating shaft and the boundary layer of the box wall, so that the measured data is closer to the representative static pressure before and after the plate. The static pressure signal is transmitted to the industrial control computer 24 through the differential pressure transmitter, and the range can be selected from 0 to 1000Pa or 0 to 2000Pa.

[0069] The technical significance of this arrangement is that the wind pressure difference does not directly measure the geometric thickness of the frost layer, but rather measures the increase in flow resistance caused by frost formation. When the current static pressure pipe 13 and the rear static pressure pipe 14 are located at the relative positions before and after the windward baffle 10, the pressure difference calculated by the industrial control computer 24 is less affected by the overall structural changes of the air duct, thus making the subsequently calculated equivalent frost layer thickness more reflective of the impact of frost on the surface of the windward baffle 10 on ventilation capacity and heat exchange efficiency.

[0070] The upper thermocouple is fixed to the side wall of the upper freezing chamber 4, and the lower thermocouple is fixed to the side wall of the lower freezing chamber 5.

[0071] The upper thermocouple is fixed to the 4th side wall of the upper freezing chamber, and the lower thermocouple is fixed to the 5th side wall of the lower freezing chamber. The fixing positions are located in the middle area of ​​the corresponding freezing chamber length direction, between the outer edge of the aquatic product stacking layer and the main flow of circulating cold air, so as to take into account both temperature representativeness and sensor anti-collision requirements. The thermocouple probe can extend into the cavity 20mm to 80mm, and is installed with a metal protective sleeve and a sealing joint to prevent cold leakage at the cavity wall perforation.

[0072] The technical considerations for placing the thermocouples on the side wall are that the side wall installation method facilitates wiring, maintenance and repeated calibration, while avoiding the need for frequent disassembly and assembly when batch switching because the sensor is directly buried inside the aquatic products; the upper and lower thermocouples collect data on the change of ambient temperature in their respective freezing chambers over time, and the industrial control computer 24 obtains the cooling rate based on the continuous sampling value.

[0073] In this invention, the cooling rate is used to characterize the heat release state during the freezing process of aquatic products in the corresponding freezing chamber. Instead of using a single temperature difference value as the basis for judgment, it can reduce the cooling deviation that occurs when different types of aquatic products with different initial temperatures are at the same set temperature. If it is necessary to improve the representativeness of the data, two or three thermocouples can also be set in parallel in each freezing chamber and the average value can be taken.

[0074] The lowest end of the inclined water guide plate 11 is connected to the drain pipe 31, wherein the drain pipe 31 extends out of the heat insulation box 2;

[0075] The inclined water guide plate 11 is set below the windward water baffle 10. Its plate surface can maintain an inclination angle of 3° to 15° relative to the horizontal plane, so that the blown-off frost and the water formed by melting can move along the plate surface to the lowest end. The inclined water guide plate 11 can be made of stainless steel plate bent into shape, and the surface can be treated with anti-icing to reduce water film retention at low temperature.

[0076] The lowest end of the water guide plate is connected to the drain pipe 31, which extends out of the insulated box 2 to the water collection container or the main drain pipe outside the box. The inner diameter of the drain pipe 31 can be 15mm to 30mm, and the outer wall of the pipe can be covered with an insulation layer. If necessary, a low-power heating cable can be installed to prevent ice from forming and clogging near the drain outlet due to low ambient temperature. This structure allows the solid frost and liquid melt water that fall off after the windward baffle plate 10 is defrosted to be discharged from the box in time, preventing them from being carried back to the evaporator coil 8 area by the circulating airflow.

[0077] Since the present invention uses a physical defrosting method, if the frost layer remains in the box after it falls off, it will re-evaporate during subsequent operation and increase the return air humidity load. Therefore, the continuous discharge function of the water guide plate and the drain pipe 31 is directly coordinated with the function of the pre-cold trap 9 to maintain the repeatable working capability of the frost-affected area.

[0078] Example 2:

[0079] Please see Figure 7 Anti-frost zone independent temperature control freezing method, including:

[0080] S1, the industrial control computer 24 reads the temperature data of the upper and lower thermocouples in real time and calculates the cooling rate of aquatic products in the upper freezing chamber 4 and the lower freezing chamber 5;

[0081] S2, Industrial control computer 24 evaluates the lag state of the actual cooling process of each freezing chamber according to the preset target cooling curve, and determines the weight of cooling capacity demand based on the relative proportion of the lag state of the two chambers.

[0082] S3, the industrial control computer 24 sends control commands to the first servo motor 22 and the second servo motor 23 according to the weight of the cooling demand, adjusts the opening angle of the upper baffle 20 and the lower baffle 21, and distributes the cold air blown out by the centrifugal fan 15 proportionally.

[0083] S4, the industrial control computer 24 reads the static pressure values ​​collected by the front static pressure pipe 13 and the rear static pressure pipe 14 in real time, calculates the wind pressure difference on both sides of the windward water baffle 10, and calculates the equivalent frost layer thickness.

[0084] S5. The industrial control computer 24 determines whether the equivalent frost layer thickness has reached the preset critical value. If it has reached the preset critical value, proceed to step S6; if it has not reached the preset critical value, return to step S1.

[0085] S6. The industrial control computer 24 controls the stepper motor 12 to rotate, adjusting the tilt angle of the windward baffle 10 to be parallel to the airflow direction. At the same time, the industrial control computer 24 controls the speed of the centrifugal fan 15 to increase to the preset overclocking speed. Based on the ratio of air pressure increase before and after the speed increase of the centrifugal fan 15, the first servo motor 22 and the second servo motor 23 control the opening angle of the upper baffle 20 and the lower baffle 21 to be reduced synchronously to the corresponding target compensation opening, so as to maintain the stability of the airflow entering each freezing chamber.

[0086] S7. After maintaining the preset defrosting time, the industrial control computer 24 controls the stepper motor 12 to restore the windward water baffle 10 to its original tilt angle, and controls the centrifugal fan 15 to restore its original speed, and returns to the execution step S1.

[0087] The freezing method is applied to the aforementioned device and executed by the industrial control computer 24 according to the cycle program; in step S1, the industrial control computer 24 reads the temperature data of the upper thermocouple and the lower thermocouple according to the set sampling period, and can calculate the cooling rate by using a sliding time window method. The time window length can be 30s to 300s, and the output unit of the cooling rate can be ℃ / min.

[0088] To ensure the smoothness and reliability of the data, after reading the temperature data, the industrial computer 24 uses a first-order hysteresis filtering algorithm or a moving average filtering algorithm to denoise the original temperature sequence, eliminating high-frequency noise signals caused by equipment vibration or electromagnetic interference, and then uses the filtered temperature data to calculate the cooling rate.

[0089] In step S2, the target cooling curve is a temperature change trajectory pre-recorded for different aquatic products. Its form can be a piecewise linear curve or a multi-segment target rate table set according to the freezing interval. The industrial control computer 24 compares the target cooling rate at the corresponding time of the target cooling curve with the current actual cooling rate to obtain the cooling lag of the upper freezing chamber 4 and the lower freezing chamber 5 respectively.

[0090] If the cooling lag of a certain freezing chamber exceeds the preset lag threshold, it means that the current heat absorption load of the zone exceeds the preset load standard, and the demand for cold air flow increases. The industrial control computer 24 performs a proportional calculation on the two cooling lags to obtain the cooling demand weight. For example, the sum of the two lags can be used as the denominator, and the individual lags can be used as the numerator to calculate the allocation ratio.

[0091] In step S3, the industrial control computer 24 outputs opening commands to the first servo motor 22 and the second servo motor 23 according to the weight of cooling demand, so that the upper baffle 20 and the lower baffle 21 form corresponding windward cross-sectional areas, and the cold air enters the upper branch air duct 17 and the lower branch air duct 18 proportionally after exiting the main air duct 16; the calculation process in steps S2 and S3 essentially constructs a dynamic cooling distribution logic model.

[0092] The purpose of this model is to accurately redistribute cold air flow based on the deviation between the actual freezing process and the target process of aquatic products in two independent freezing chambers under the condition of a single main cold source. Logically, the model consists of a cooling lag assessment submodule and a weight allocation submodule: the cooling lag assessment submodule receives real-time temperature data from the upper and lower thermocouples and the pre-stored target cooling curve as input, calculates and outputs the cooling lag amount of the upper freezing chamber 4 and the lower freezing chamber 5; the weight allocation submodule receives the cooling lag amount as input and outputs the cooling demand weight through proportional calculation.

[0093] The control module outputs the opening instructions of the two servo motors according to the weight; the model as a whole represents the dynamic supply and demand balance between the time-varying characteristics of the heat load in the refrigeration environment and the cooling capacity of the refrigeration system. That is, when the heat load of a certain zone is high and the cooling is slow, the system automatically increases the opening of the baffle of that zone to increase the supply of cooling capacity through the model.

[0094] In step S4, the industrial control computer 24 continuously receives the pressure signals of the front static pressure pipe 13 and the rear static pressure pipe 14, calculates the wind pressure difference on both sides of the windward water baffle 10, and converts it into the equivalent frost layer thickness. The equivalent frost layer thickness in this invention is a virtual thickness parameter obtained by inverting the wind resistance increment, which is used to evaluate the adverse effects of the degree of frost on ventilation and heat exchange.

[0095] In step S5, when the equivalent frost layer thickness is lower than the preset critical value, the system maintains normal freezing; when the equivalent frost layer thickness reaches the preset critical value, proceed to step S6.

[0096] In step S6, the industrial control computer 24 sends an angle command to the stepper motor 12, causing the windward baffle 10 to rotate to a position parallel to the airflow direction, reducing the obstruction of the airflow by the baffle surface; at the same time, it sends an acceleration command to the centrifugal fan 15, causing the circulating air to increase temporarily; and sends a synchronous reduction command to the first servo motor 22 and the second servo motor 23 to counteract the effect of the fan speed increase on the air volume in the freezing chamber; thus, the wind speed that reaches the set defrosting threshold mainly acts on the vicinity of the windward baffle 10, causing the frost layer to fall off, while the air volume fluctuation entering the upper freezing chamber 4 and the lower freezing chamber 5 remains within the preset allowable error range;

[0097] In step S7, after the defrosting time reaches the set value, the windward baffle 10 returns to its original tilt angle, the centrifugal fan 15 returns to its original speed, and the two air duct baffles also return to the corresponding opening degree calculated based on the real-time cooling demand weight. The system then re-executes the cycle from step S1 to step S7.

[0098] Using this method, zoned temperature control and defrosting can be linked under continuous cooling conditions, reducing the temperature rise in the cavity caused by traditional shutdown defrosting. The calculation and control logic of steps S1 to S3 can be executed in the following order: the industrial control computer 24 reads the temperature values ​​of the upper and lower thermocouples at the current time and the previous sampling time, and forms a temperature sequence within the sliding time window; the industrial control computer 24 performs adjacent time difference and time averaging on each temperature sequence to obtain the actual cooling rate of the upper freezing cavity 4 and the lower freezing cavity 5.

[0099] The industrial computer 24 retrieves the target cooling rate corresponding to the current running time or current temperature range from the pre-stored target cooling curve, and compares it with the actual cooling rate to obtain the cooling lag of the corresponding partition. The physical meaning of the cooling lag is the degree of sluggishness of the current actual freezing process of the corresponding partition relative to the target freezing process. When the actual cooling rate reaches or exceeds the target cooling rate, the cooling lag of the partition can be recorded as zero to avoid negative values ​​that could cause distortion of the allocation logic.

[0100] The industrial control computer 24 only proportionally allocates cooling lag amounts greater than zero and outputs cooling demand weights. If the cooling lag amounts of both zones are zero, the baffle opening of the previous control cycle is maintained, or the upper throttling baffle 20 and the lower throttling baffle 21 are restored to the preset reference opening. The decision-making role of the cooling demand weight is to characterize the relative demand of the two zones for circulating cold air under the same main cold source, and to serve as the direct input for the baffle opening allocation in step S3.

[0101] To facilitate engineering implementation, the industrial control computer 24 can first look up the target opening of the upper baffle 20 and the lower baffle 21 according to the weight of the cooling demand, and then send the corresponding angle command to the first servo motor 22 and the second servo motor 23 to achieve precise physical position control of the servo motors.

[0102] Specifically, the industrial control computer 24 presets the reference total opening of the baffle corresponding to the total air volume. For example, the sum of the two openings is kept at a constant value. The reference total opening is multiplied by the cooling demand weight of the upper freezing chamber 4 and the cooling demand weight of the lower freezing chamber 5 respectively to obtain the theoretical target opening of the upper baffle 20 and the theoretical target opening of the lower baffle 21.

[0103] If the calculated theoretical target opening is lower than the lower limit threshold for maintaining minimum ventilation, it is forcibly set to the lower limit threshold, and the remaining opening is allocated to another baffle. The processed target opening is converted into control signal outputs for the first servo motor 22 and the second servo motor 23, thereby realizing the complete flow of data from weight ratio to specific motor execution action.

[0104] The preset target cooling curve can be determined as follows: For different aquatic products such as fish, shrimp, and shellfish, record the freezing process temperature trajectory that meets the quality requirements during the trial operation, and organize it into a target cooling rate table indexed by time period or temperature range; when the industrial control computer 24 is running, call the corresponding rate table according to the product category, so that the cooling lag has a clear data source.

[0105] The purpose of the preset critical value is to distinguish between the normal freezing state and the state that requires the defrosting procedure. It can be determined by calibration, that is, under the conditions of no load or standard load, the amount of frost on the windward baffle 10 is gradually increased and the increase of wind pressure difference, the degree of air supply attenuation in the cavity and the change of air duct resistance in front of evaporator coil 8 are recorded simultaneously. When the air supply capacity decreases to the preset allowable upper limit, the corresponding equivalent frost layer thickness is set as the preset critical value.

[0106] The preset defrosting time is used to limit the duration of step S6. Its physical meaning is the maintenance time required for the brittle frost layer on the surface of the windward water baffle 10 to be basically removed without significantly disturbing the zone freezing process. This time can be determined by multiple defrosting tests, with the recovery ratio of wind pressure difference after defrosting and the temperature fluctuation range of the freezing chamber as the comprehensive basis.

[0107] The calculation of the equivalent frost layer thickness in step S4 includes: the industrial control computer 24 obtains the wind pressure difference increment based on the current wind pressure difference and the preset frost-free initial wind pressure difference; and evaluates and obtains the equivalent frost layer thickness based on the resistance conversion relationship corresponding to the current tilt angle of the windward water deflector 10.

[0108] The equivalent frost thickness calculation in step S4 adopts the benchmark differential pressure method. When the equipment is started for the first time or when it is manually confirmed that there is no frost on the surface of the windward baffle 10, the industrial control computer 24 records the wind pressure difference between the front static pressure pipe 13 and the rear static pressure pipe 14 at that moment as the initial wind pressure difference without frost. The equivalent frost thickness calculation in step S4 is actually based on an equivalent frost thickness evaluation model. The purpose of this model is to accurately estimate the equivalent thickness of frost on the surface of the windward baffle 10 by means of the air duct resistance increment under the conditions of low temperature and high humidity without adding complex optical or microwave sensors.

[0109] Logically, the model includes a reference differential pressure sub-model and an angle correction sub-model: the reference differential pressure sub-model receives real-time static pressure collected by the front static pressure pipe 13 and the rear static pressure pipe 14 as input, compares it with the preset frost-free initial wind pressure difference, and outputs the wind pressure difference increment; the angle correction sub-model receives the tilt angle fed back by the stepper motor 12 as input, and normalizes the wind pressure difference increment through the tilt angle sine conversion coefficient.

[0110] The main model combines the calculation results of the two to output the equivalent frost layer thickness at a unified scale. The model as a whole characterizes the aerodynamic causal relationship between the increase in the windward projected area and the change in surface roughness caused by frost on the plate when the fluid flows through the inclined baffle in the confined airway and the local static pressure loss. As the frost layer accumulates, the airflow channel narrows and the surface friction increases, and the static pressure difference before and after the windward baffle 10 increases accordingly. By separating this pressure difference increment and combining it with the change in the projected surface caused by the baffle inclination angle, the virtual frost layer geometric characteristics can be inferred.

[0111] During subsequent operation, the industrial control computer 24 continuously reads the current wind pressure difference and calculates the difference between the current wind pressure difference and the initial wind pressure difference without frost, thus obtaining the wind pressure difference increment. Since the windward water deflector 10 has a variable tilt angle, the windward projection area formed by the same thickness of frost layer on the airflow is different at different angles. Therefore, the industrial control computer 24 introduces a sine conversion coefficient of tilt angle to correct the wind pressure difference increment.

[0112] The conversion factor can be obtained based on equipment calibration tests, or it can be a proportional coefficient expression based on the sine value of the current tilt angle of the windward water deflector 10. The industrial control computer 24 divides the wind pressure difference increment by the conversion factor and outputs the equivalent frost layer thickness. For example, when the normal working angle of the windward water deflector 10 is 30°, the industrial control computer 24 can call the coefficient table for the corresponding angle to convert the change in aerodynamic resistance into the equivalent frost layer thickness value under a unified scale.

[0113] The characteristic of this calculation method is that it does not require the deployment of optical ranging devices or microwave transmitters in low-temperature and high-humidity environments. Instead, it directly uses the existing static pressure information in the air duct to reflect the degree of frost, thereby reducing the probability of the sensor becoming inaccurate due to fog, condensation and low-temperature icing. The industrial control computer 24 can set the equivalent frost layer thickness threshold to a calibration range of 2mm to 10mm. When the threshold is exceeded, a physical defrosting program is executed.

[0114] The input signals for step S4 include the static pressure value in front of the plate collected by the front static pressure pipe 13, the static pressure value behind the plate collected by the rear static pressure pipe 14, and the tilt angle of the windward baffle 10 corresponding to the current position of the stepper motor 12; the industrial control computer 24 can first read the static pressure value in front of the plate and the static pressure value behind the plate in the same cycle, and then calculate the difference between the two as the current wind pressure difference; call the initial wind pressure difference pre-stored by the equipment in the frost-free state, and subtract the two to obtain the wind pressure difference increment;

[0115] The physical meaning of the wind pressure difference increment is the new flow resistance relative to the frost-free reference state. It is mainly used to eliminate the influence of the inherent structural resistance of the air duct on the frost determination. If the calculated wind pressure difference increment is less than or equal to 0, the industrial control computer 24 can directly record the equivalent frost layer thickness as zero, indicating that the current resistance level is not higher than the frost-free reference state.

[0116] To further clarify the specific calculation logic of step four, the sine conversion factor for the tilt angle can be determined as follows: First, fix the windward water deflector 10 at several commonly used working angles on the equipment prototype. At each angle, artificially form several standard frost layers or equivalent flow-blocking layers of known thickness, record the relationship between the corresponding wind pressure difference increment and the known thickness, and then establish a correspondence table between the angle and the conversion factor. When the industrial control computer 24 runs, select the conversion factor from the correspondence table according to the current angle, or obtain the conversion factor by interpolation of adjacent angles.

[0117] After adopting this processing flow, the equivalent frost layer thickness is not a directly measured geometric thickness, but rather a uniform mapping of resistance changes under different baffle angles and different wind pressure differences to a comparable thickness characterization value. This characterization value is passed to step S5 as the input for determining whether to enter the defrosting procedure. As a convenient way of expression, the industrial control computer 24 can perform the conversion according to the following relationship:

[0118]

[0119] The sine conversion coefficient of the tilt angle in the above conversion relationship is preferably a proportional quantity obtained through calibration. Its dimension can be set in advance according to the correspondence between thickness and pressure difference, so as to ensure that the equivalent frost layer thickness output under different working conditions is comparable; that is, the dimension of the calibration resistance conversion constant is the ratio of pressure to length.

[0120] To further clarify the details of the algorithm implementation, the specific calculation logic of the tilt angle sine conversion coefficient is as follows: the tilt angle sine conversion coefficient is equal to the calibration resistance conversion constant multiplied by the sine value of the current tilt angle; where the calibration resistance conversion constant is a model constant that reflects the mapping relationship between wind pressure difference and frost layer thickness, which is pre-measured by the equipment under standard test conditions.

[0121] When calculating, the industrial computer 24 obtains the tilt angle corresponding to the current rotation angle of the stepper motor 12, calls the math library to calculate its sine value and multiplies it by the calibration resistance conversion constant to obtain the conversion coefficient; it subtracts the initial wind pressure difference without frost from the current wind pressure difference to obtain the wind pressure difference increment; and it performs a division operation to output the equivalent frost layer thickness.

[0122] If the tilt angle is zero during the calculation process, that is, the baffle is completely parallel to the airflow, in order to avoid the denominator being zero and causing program abnormality, the industrial control computer 24 will trigger the boundary protection logic, directly skip the thickness calculation and keep the thickness value of the previous effective cycle.

[0123] In step S6, the preset overclocking speed is a preset multiple of the rated speed, and the industrial control computer 24 controls the speed of the centrifugal fan 15 to increase to the preset overclocking speed within a preset acceleration time.

[0124] The preset overclocking speed in step S6 is used to enhance the airflow shearing effect near the windward baffle 10 within a preset time threshold; the rated speed of the centrifugal fan 15 can be determined according to the equipment model, for example, the rated speed is 1200r / min to 2400r / min, and the preset overclocking speed can be set to 1.2 times to 1.8 times the rated speed, preferably 1.3 times to 1.5 times.

[0125] The preset acceleration time can be set from 1s to 5s. The industrial control computer 24 controls the centrifugal fan 15 to complete the speed increase within this time through the frequency converter or motor driver. The reason for using a preset acceleration time instead of instantaneous jump is that the controllable speed increase slope helps to reduce the mechanical shock of the motor and the vibration of the air duct. At the same time as issuing the speed increase command of the centrifugal fan 15, the industrial control computer 24 outputs a compensation command to the first servo motor 22 and the second servo motor 23 to synchronously reduce the baffle opening. The compensation amount can be pre-calibrated according to the pressure rise change before and after the fan speed increase, or a lookup table relationship can be established based on historical operating data.

[0126] The above-mentioned synchronous control process is essentially based on an air volume compensation control logic model. The purpose of this model is to enhance the local airflow shear force in the pre-cold trap 9 area during the physical defrosting stage, while maintaining the stability of the air supply volume in the upper freezing chamber 4 and the lower freezing chamber 5, so as to avoid the defrosting action causing adverse thermal shock to the freezing curve.

[0127] The model logically includes an acceleration command generation module and an opening compensation calculation module: the acceleration command generation module receives a preset overclocking speed and a preset acceleration time as input, and outputs the frequency conversion control signal of the fan; the opening compensation calculation module receives the fan's acceleration multiple as input, and calculates and outputs the target reduction opening of the first servo motor 22 and the second servo motor 23 according to the preset compensation table or the calibrated pressure rise relationship.

[0128] The pressure rise relationship and its theoretical basis are as follows: According to the fan similarity law in fluid mechanics, the total air pressure generated by the fan is proportional to the square of its rotational speed; when the centrifugal fan speed is increased to a preset multiple of the rated speed, the total air pressure will increase to the square of that multiple; in order to maintain the flow rate in the branch duct, the local resistance of the branch duct must also be increased to the square of the original.

[0129] Since the local resistance is inversely proportional to a specific function of the baffle opening, which is a curve function of the correspondence between the baffle opening and the local resistance coefficient obtained in advance through fluid simulation or wind tunnel test calibration, the industrial control computer 24 calculates the baffle reduction angle required for the square multiple of the resistance based on this theoretical relationship. In the specific programming implementation, the industrial control computer 24 inputs the current acceleration multiple into the preset opening resistance inversion function or directly queries the compensation mapping table generated in advance based on this theory to obtain the corresponding target reduction opening, subtracts it from the current opening under normal temperature control, and outputs the baffle opening command actually executed. In this way, the fluctuation range of the cold air flow in the cavity during the defrosting period is strictly guaranteed from the theoretical and algorithmic levels, supporting its beneficial effect of not affecting the freezing curve in the cavity.

[0130] The model as a whole represents the dynamic balance relationship of flow between the total pressure increase and the local resistance adjustment of the branch duct in the pipeline system. Due to the over-frequency of the fan, the total air pressure and total air volume increase. Under the condition that the resistance of the branch duct remains unchanged, the cold air volume entering the freezing chamber will exceed the predetermined range. Therefore, the system increases the local resistance of the branch by synchronously reducing the opening of the baffle, which offsets the increase in the branch flow caused by the increase in total air pressure. In this way, the newly added air kinetic energy is concentrated and dissipated in the main duct area of ​​the front cold trap 9, so as to realize the physical aerodynamic defrosting of the surface of the windward baffle 10.

[0131] As a result, the local airflow velocity near the windward baffle 10 meets the set requirements due to the overclocking of the fan. The brittle frost layer attached to the surface of the windward baffle 10 is removed under the action of tangential aerodynamic force, and the actual air volume change entering the upper freezing chamber 4 and the lower freezing chamber 5 is controlled within the set range, for example, not exceeding 10% of the normal air volume deviation. The defrosting duration can be set to 5s to 15s. After the time is over, the industrial control computer 24 makes the centrifugal fan 15 return to the rated speed according to the preset deceleration curve, and releases the baffle compensation opening, restoring the zoned air supply control based on the cooling demand weight.

[0132] The logic of preset overclocking speed is not simply to increase the overall air volume, but to increase the tangential aerodynamic force on the frost layer by using a short-term increase in local wind speed after the windward baffle 10 is rotated to be parallel to the airflow direction, so that the frost layer that is preferentially accumulated on the surface of the windward baffle 10 will detach.

[0133] The preset multiplier can be determined through calibration tests: First, gradually increase the centrifugal fan speed by 15 under different degrees of frost accumulation, and record the frost removal effect, the vibration level of the chamber, and the temperature fluctuation of the freezing chamber. When the speed range that can stably blow off the frost without causing the air supply deviation of the freezing chamber to exceed the limit is reached, the multiplier corresponding to this range is set as the preset multiplier.

[0134] The decision-making role of the preset acceleration time is to limit the dynamic process of the centrifugal fan 15 transitioning from the normal operation state to the defrosting operation state. If the acceleration is too fast, it is easy to cause air duct impact and pressure fluctuation. If the acceleration is too slow, it is not conducive to forming an effective defrosting peak. Therefore, it can be set comprehensively based on the fan rotational inertia, inverter response time and air duct structural strength.

[0135] To make the control flow of step S6 clearer, the industrial control computer 24 can first read the current speed of the centrifugal fan 15 and the current opening of the upper baffle 20 and the lower baffle 21; generate a speed-up command according to the preset overclocking speed and preset acceleration time, and at the same time call the pre-stored compensation table to determine the target reduction opening of the two baffles; the industrial control computer 24 synchronously outputs control signals to the centrifugal fan 15, the first servo motor 22 and the second servo motor 23, so that the fan speed-up process and the baffle compensation process are completed within the same defrosting cycle;

[0136] The compensation table can be pre-established by the experiment. Its input includes at least the fan speed increase multiple, and the output is the corresponding reduction of the opening range of the upper baffle 20 and the lower baffle 21. The purpose of the industrial control computer 24 calling the table is to concentrate more incremental wind pressure on the vicinity of the windward baffle 10, rather than directly transmitting it to the inside of the two refrigeration chambers.

[0137] After the defrosting is completed, the industrial control computer 24 restores the centrifugal fan 15 to its original speed according to the preset deceleration curve, and releases the compensation of the two baffles, returning to the normal opening degree determined by the cooling demand weight, so that the defrosting action and the zone temperature control action are continuously connected in the same control system.

[0138] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A frost-prevention, zoned, independently temperature-controlled aquatic product freezing device, characterized in that: include: The insulated box (2) is provided with a horizontally placed polyurethane insulation partition (3), which divides the insulated box (2) into an upper freezing chamber (4) with an upper thermocouple and a lower freezing chamber (5) with a lower thermocouple. Evaporator coil (8) is located inside the insulated box (2); A front cold trap (9) is located in front of the air inlet side of the evaporator coil (8), including a windward baffle (10) and an inclined water guide plate (11) located below it. The windward baffle (10) is connected to a stepper motor (12), and a front static pressure pipe (13) and a rear static pressure pipe (14) are respectively provided on its two sides. Centrifugal fan (15) is connected to the air outlet side of the evaporator coil (8), and its outlet is connected to the main air duct (16). The main air duct (16) is divided into an upper branch air duct (17) and a lower branch air duct (18) that connect the upper freezing chamber (4) and the lower freezing chamber (5) respectively. The flow interception assembly (19) includes an upper flow interception baffle (20) and a lower flow interception baffle (21). The upper flow interception baffle (20) is hinged to the inlet of the upper branch air duct (17) and connected to a first servo motor (22). The lower flow interception baffle (21) is hinged to the inlet of the lower branch air duct (18) and connected to a second servo motor (23). The industrial computer (24) is electrically connected to the stepper motor (12), centrifugal fan (15), first servo motor (22), second servo motor (23), upper thermocouple, lower thermocouple, front static pressure tube (13) and rear static pressure tube (14). The heat insulation box (2) has a support frame (25) installed on the bottom surface inside, and the evaporator coil (8) is fixed on the support frame (25). The evaporator coil (8) is a copper tube with aluminum fins. The windward water deflector (10) is an aluminum alloy plate. The surface of the windward water deflector (10) is machined with longitudinal guide grooves (26). The two ends of the windward water deflector (10) are installed on the side wall of the heat insulation box (2) through rotating bearings (27). The rotating shaft of the driving end of the windward water deflector (10) is directly connected to the stepper motor (12) through a coupling (28). The stepper motor (12) is fixed to the outer wall of the heat insulation box (2). The air outlet of the upper freezing chamber (4) is connected to the upper return air duct (29), and the air outlet of the lower freezing chamber (5) is connected to the lower return air duct (30). The upper return air duct (29) and the lower return air duct (30) are connected to the windward side of the windward baffle plate (10) after they merge. The front static pressure pipe (13) is fixed in front of the windward side of the windward water baffle (10), and the rear static pressure pipe (14) is fixed behind the leeward side of the windward water baffle (10). The upper thermocouple is fixed to the side wall of the upper freezing chamber (4), and the lower thermocouple is fixed to the side wall of the lower freezing chamber (5). The lowest end of the inclined water guide plate (11) is connected to the drain pipe (31), wherein the drain pipe (31) extends out of the heat insulation box (2).

2. A frost-prevention zoned independent temperature control freezing method, applied to the frost-prevention zoned independent temperature control aquatic product freezing device (1) as described in claim 1, characterized in that, include: S1. The industrial control computer (24) reads the temperature data of the upper thermocouple and the lower thermocouple in real time, and calculates the cooling rate of the aquatic products in the upper freezing chamber (4) and the lower freezing chamber (5); S2. The industrial control computer (24) evaluates the lag state of the actual cooling process of each freezing chamber according to the preset target cooling curve, and determines the weight of the cooling demand based on the relative proportion of the lag state of the two chambers. S3. The industrial control computer (24) sends control commands to the first servo motor (22) and the second servo motor (23) according to the cooling demand weight, adjusts the opening angle of the upper baffle (20) and the lower baffle (21), and distributes the cold air blown out by the centrifugal fan (15) proportionally. S4. The industrial control computer (24) reads the static pressure values ​​collected by the front static pressure pipe (13) and the rear static pressure pipe (14) in real time, calculates the wind pressure difference on both sides of the windward water baffle (10), and calculates the equivalent frost layer thickness. S5. The industrial control computer (24) determines whether the equivalent frost layer thickness has reached a preset critical value. If it has reached the preset critical value, it executes step S6; if it has not reached the preset critical value, it returns to execute step S1. S6. The industrial control computer (24) controls the stepper motor (12) to rotate, adjusts the tilt angle of the windward baffle (10) to be parallel to the airflow direction, and at the same time, the industrial control computer (24) controls the speed of the centrifugal fan (15) to increase to the preset overclocking speed, and according to the wind pressure increase ratio before and after the speed of the centrifugal fan (15) is increased, controls the first servo motor (22) and the second servo motor (23) to synchronously reduce the opening angle of the upper baffle (20) and the lower baffle (21) to the corresponding target compensation opening, so as to maintain the stability of the airflow entering each freezing chamber; S7. After maintaining the preset defrosting time, the industrial control computer (24) controls the stepper motor (12) to restore the windward water baffle (10) to its original tilt angle, and controls the centrifugal fan (15) to restore its original speed, and returns to the execution of step S1; The calculation of the equivalent frost layer thickness in step S4 includes: the industrial control computer (24) obtains the wind pressure difference increment based on the current wind pressure difference and the preset frost-free initial wind pressure difference; and evaluates and obtains the equivalent frost layer thickness based on the resistance conversion relationship corresponding to the current tilt angle of the windward water deflector (10); In step S6, the preset overclocking speed is a preset multiple of the rated speed, and the industrial control computer (24) controls the speed of the centrifugal fan (15) to increase to the preset overclocking speed within a preset acceleration time.

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