Intelligent freeze-drying preparation method based on multi-parameter feedback and special energy bar prepared by the method

Abstract

The application provides a kind of intelligent freeze-drying preparation method based on multi-parameter feedback and a special energy bar prepared by the method.The method comprises: providing an initial paste, controlling a freeze-drying device to pre-freeze the initial paste into a solid; extracting air to form a vacuum and switching to a main sublimation stage, temporarily closing the main exhaust channel at a set time interval to measure the absolute pressure rising slope; when the slope is lower than the reference boundary value, the heating power is lowered and cold inert gas is injected, then the isolation butterfly valve is fully opened to cause a sudden drop in air pressure, and the water vapor escape channel is dredged by differential pressure expansion; switching to a resolution dehydration stage, when the water capture rate is lower than the lower limit of the calibration, the heating temperature is locked and the absolute pressure in the device is alternately raised and lowered to promote the forced desorption and separation of deep bound water, and the vacuum is broken to obtain a shaped special energy bar. The application can effectively dredge the mass transfer channel and remove the bound water at a safe temperature, maintaining the stability of the internal components and microstructure of the product.

Description

Technical Field

[0001] This invention relates to the fields of food processing and vacuum freeze-drying technology, and in particular to an intelligent freeze-drying preparation method based on multi-parameter feedback and a special energy bar prepared by the method. Background Technology

[0002] Vacuum freeze-drying technology is currently widely used in the processing and preparation of highly nutritious foods to preserve the original components and structure of the materials. During the main sublimation stage of freeze-drying, as external moisture is removed, a dry, porous matrix framework gradually forms around the material. Water vapor generated by the sublimation of residual ice crystals needs to penetrate this porous framework to escape to the external environment. As the dehydration process progresses deeper into the material, the physical path for water vapor escape becomes longer, leading to increased mass transfer resistance to gas flow. If a fixed heating power input is maintained at this point, heat not consumed by the latent heat of phase change easily accumulates at the material's internal interface, causing an abnormal rise in localized temperatures. When the ice crystals are depleted and the desorption stage begins, some bound water is often tightly adsorbed deep within the porous framework through physical action. A high activation energy is required to remove this water from its adsorption sites.

[0003] Conventional processing methods typically rely on increasing the overall temperature of the heating source to accelerate the removal of this deep-bound water. Higher temperatures subject the material matrix to additional heat load. For energy bar products containing peptides, proteins, and high-energy lipid microparticles, continuous heating can easily lead to plastic softening of the solid-phase cross-linked network and shrinkage and collapse of micropores. Increased temperatures can also easily disrupt the solid-state physical encapsulation of the internal high-energy lipid microparticles, altering the physical conformation of the nutrient molecules. These factors negatively impact the three-dimensional compressive rigidity of the molded product in its later stages and its physicochemical state during storage. Therefore, adjusting process parameters in a timely manner according to the dehydration state during the drying process to balance moisture removal efficiency with the stability of the product's internal structure is a crucial aspect that needs optimization in the current process. Summary of the Invention

[0004] The purpose of this invention is to provide an intelligent freeze-drying preparation method based on multi-parameter feedback and a special energy bar prepared by the method, so as to solve the technical problems of deep heat accumulation caused by the obstruction of mass transfer in micro-pores during the dehydration process in existing freeze-drying processes, and the deformation and collapse of the porous skeleton of the material and damage to the internal high-energy nutrient components caused by relying on overall high temperature to remove bound water.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a smart freeze-drying preparation method based on multi-parameter feedback, comprising: Provide initial paste; The freeze-drying equipment is controlled to pre-freeze the initial paste, causing the initial paste to solidify into a pre-frozen solid; The freeze-drying equipment is evacuated to create a vacuum, and the heating shelf and cold trap assembly are activated to enter the main sublimation stage, causing the ice crystals in the pre-frozen solid to sublimate into water vapor. During the main sublimation stage, the main exhaust channel is briefly closed at set time intervals, and the absolute pressure rise slope during the closed period is calculated. When the absolute pressure rise slope is lower than the reference boundary value, the output power of the heating shelf is reduced, and cold inert gas is injected into the freeze-drying equipment. Then, the isolation butterfly valve set at the main exhaust channel is fully opened to generate a sudden drop in air pressure. The pressure difference expansion is used to clear the water vapor escape channel until the absolute pressure rise slope recovers to not lower than the reference boundary value. The process then transitions to the dehydration and analysis phase, continuously acquiring the moisture capture rate of the cold trap component. When the moisture capture rate is lower than the calibrated lower limit value, the output temperature of the heating shelf is locked and the alternating suction and extraction step is started, alternatingly raising and lowering the absolute air pressure inside the freeze-drying equipment, causing the deep bound water to be forcibly desorbed and separated, and a special energy bar is produced.

[0006] Optionally, before the freeze-drying equipment pre-freezes the initial paste, a batching step is included: High-energy lipid microparticles, polypeptide protein powders, and carbohydrate matrix are obtained according to a predetermined weight ratio. Pour all the obtained nutrient components into a homogenizer and mix them. Add purified water to adjust the consistency into a thick paste. The viscous slurry is subjected to microbubble removal treatment using an ultrasonic component to eliminate the free air clusters trapped inside, thus obtaining the initial paste.

[0007] Optionally, the freeze-drying equipment is used to pre-freeze the initial paste, and the pre-freezing step specifically includes: The refrigeration compressor unit located at the bottom of the freeze-drying equipment is controlled to operate, and the surface temperature of the heating shelf is gradually reduced at a fixed cooling rate; A probe thermocouple inserted into the geometric center of the initial paste is used to continuously feed back the core temperature value and monitor the thermodynamic change trajectory of the core temperature value as it drops to the freezing point region. When the core temperature drops to the target supercooling limit, the refrigeration compressor unit is kept running until the initial paste is completely solidified.

[0008] Optionally, the process of evacuating the internal air of the freeze-drying equipment to create a vacuum, and then activating the heating shelf and cold trap assembly to enter the main sublimation stage, which specifically includes: Turn on the multi-stage rotary vane vacuum pump group to extract the atmospheric pressure air accumulated in the freeze-drying equipment, so that the internal absolute air pressure is reduced to below the rated working vacuum level. The cold trap assembly is activated to condense the free water vapor generated by the sublimation of ice crystals into a solid ice layer, preventing water vapor from flowing back and eroding the pre-frozen solid.

[0009] Optionally, the step of continuously acquiring the moisture capture rate of the cold trap component specifically includes: Monitor the incremental data of frost formation on the surface of the cold trap assembly; Based on the frost increment data within the set calculation period, the sublimated water vapor mass migration rate is calculated. The sublimated water vapor mass migration rate is used as the moisture capture rate to characterize the progress of dehydration.

[0010] Optionally, the step of briefly closing the main exhaust channel at set time intervals and calculating the absolute pressure rise slope during the sealed period specifically includes: The main control device controls the closure of the isolation butterfly valve located at the main exhaust channel to cut off the exhaust circuit; Record the dynamic growth trajectory of the absolute atmospheric pressure within a specified number of seconds, and extract the rate of increase obtained after linear fitting as the absolute atmospheric pressure rise slope. Once extraction is complete, immediately reopen the isolation butterfly valve to restore normal air extraction.

[0011] Optionally, the step of injecting cold inert gas into the freeze-drying equipment and then controlling the isolation butterfly valve located at the main exhaust channel to fully open to generate a sudden drop in gas pressure specifically includes: Open the back pressure compensation valve on the air inlet pipe to introduce the low-temperature high-purity nitrogen gas stored in the external air source connected to the freeze-drying equipment into the freeze-drying equipment, thereby increasing the internal static pressure to compress the outer barrier layer that has been formed. The isolation butterfly valve located at the main exhaust channel is fully opened to rapidly reduce pressure, effectively expelling saturated water vapor that is blocked deep in the micropores by utilizing a preset multiple of pressure difference.

[0012] Optionally, the alternating suction and withdrawal step involves alternating increases and decreases in the absolute pressure inside the freeze-drying equipment. This alternating suction and withdrawal step specifically includes: Stop the heating shelf from heating further, so that the internal environment of the freeze-drying equipment is maintained within the set safe thermodynamic range; Close the main exhaust channel and introduce heat-conducting medium gas into the freeze-drying equipment to make the internal absolute pressure rise to the pulse high pressure value, so that the heat-conducting medium gas can penetrate into the deep interior to transfer heat. After maintaining the target heat transfer time, start the vacuum extraction action at full speed to rapidly reduce the internal absolute pressure to the lower limit of the ultimate vacuum value, and force the deep bound water to desorb and separate through physical negative pressure.

[0013] Optionally, after the alternating increases and decreases in the absolute pressure inside the freeze-drying equipment, the dehydration state of the material is assessed, and the determination process specifically includes: Repeat the alternating suction and suction steps while simultaneously monitoring the absolute humidity value in the main exhaust channel; When the absolute humidity value is below the set endpoint boundary for multiple consecutive detection cycles and remains stable, the cycle is interrupted, the final drying is determined to be complete, and the vacuum chamber is broken and the product is removed.

[0014] In addition, the present invention also provides a special energy bar, which is prepared by the above-mentioned intelligent freeze-drying preparation method based on multi-parameter feedback; the special energy bar has an interconnected multi-dimensional pressure-resistant microporous network inside, and high-energy lipid microparticles that maintain solid physical conformation are deeply sealed inside.

[0015] The present invention has achieved the following beneficial effects: This invention uses the absolute pressure rise rate calculated at set time intervals during the main sublimation stage to assess the fluid mass transfer state of the micro-pores in real time. When increased flow resistance is detected, the heating power is actively reduced. Furthermore, the injection of cold inert gas, combined with the pressure-reducing expansion airflow generated by fully opening the isolation butterfly valve, promptly clears blocked water vapor escape channels, preventing localized heating caused by heat retention deep within the material. After transitioning to the dehydration stage, the system actively locks the temperature parameters of the heating shelf based on changes in the moisture capture rate of the cold trap assembly. Within a set safe thermodynamic range, the absolute pressure inside the freeze-drying equipment is alternately raised and lowered, utilizing the convective heat transfer of the heat-conducting medium gas and physical negative pressure to force the desorption and separation of deep-bound water. This dynamic regulation mechanism, while advancing the process of removing bound water, avoids plastic softening and pore collapse of the cross-linked porous framework under high heat load, ensuring that the final special energy bar retains an interconnected multidimensional compressive microporous network. Furthermore, it allows high-energy lipid microparticles to be physically encapsulated in the cross-linked wall layer within a suitable temperature range, guaranteeing that the product's physicochemical parameters remain stable and its three-dimensional framework mechanical properties remain intact during the storage period.

[0016] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a block diagram showing the module composition and connection of the hardware execution system in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the main control steps of the intelligent freeze-drying preparation method in this embodiment of the invention. Figure 3 A flowchart of the initial paste preparation and degassing steps is provided for embodiments of the present invention; Figure 4 This is a dynamic unblocking flowchart based on absolute pressure calculation for the main sublimation stage in this embodiment of the invention; Figure 5 This is a flowchart illustrating the alternating suction and forced desorption steps in the dehydration stage of this invention. Figure 6 This is a flowchart illustrating the loop termination determination based on absolute humidity values ​​in an embodiment of the present invention. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] This embodiment provides a smart freeze-drying preparation method based on multi-parameter feedback. For example... Figure 1 As shown, the hardware execution system of this method includes a main control device 10, a raw material preparation pipeline, a homogenizer 20, an ultrasonic component 30, a freeze-drying device 40 and its associated refrigeration compressor unit 41, a cooling heat transfer circuit, a multi-stage rotary vane vacuum pump unit 42, and a cold trap assembly 43. The main control device 10 integrates a microprocessor, a digital signal processing chip, and a storage unit, and interacts with sensor nodes and actuators within the system via a fieldbus protocol. The sensor network is equipped with a differential pressure transmitter, a thin-film capacitive absolute pressure vacuum gauge 45, an insertion probe thermocouple 46, a weighing sensor array 70, and a tunable semiconductor laser absorption spectroscopy gas analysis probe 80. The actuators are equipped with an AC variable frequency drive motor, an isolation butterfly valve 51 located in the main exhaust channel 50, a back pressure compensation valve 61 on the intake pipeline 60, a solid-state relay heating group within the heating shelf 44, and a refrigeration compressor unit 41. The main control device 10 executes a control algorithm based on the acquired discrete physical variable sequence, outputting duty cycle signals and level commands to regulate the corresponding actuators.

[0021] Combination Figure 2 The main process steps of the method shown are as follows: Figure 3As shown, an initial paste is provided, and a batching step is included before the freeze-drying equipment 40 pre-freezes the initial paste. Specifically, the main control equipment 10 obtains high-energy lipid microparticles, polypeptide protein powder, and carbohydrate matrix according to predetermined weight ratios. To meet the metabolic demands of high-load task environments, the predetermined weight ratios of each solid nutrient component in this embodiment are set as follows: the high-energy lipid microparticles, containing medium-chain triglycerides and antioxidants, account for 35%~45%; the polypeptide protein powder, composed of whey protein hydrolysate, accounts for 25%~35%; and the carbohydrate matrix, composed of isomaltooligosaccharide and maltodextrin, accounts for 20%~30%. Weighing sensors are distributed at the bottom support structure of each raw material storage silo. When the material in the storage silo is discharged through the bottom screw conveyor, the weighing sensor outputs a differential analog voltage signal. This signal is transmitted to the analog front-end circuit of the main control equipment 10 through a shielded cable, and after signal gain and low-pass filter noise reduction processing, it is converted into a discrete digital quality signal sequence by an analog-to-digital converter. The main control device 10 compares the real-time read mass data sequence with the pre-stored predetermined weight ratio parameters to calculate the discharge mass difference. Based on this difference, the main control device 10 outputs a pulse width modulation command to the frequency converter of the screw conveyor. As the actual discharge volume approaches the set value, the main control device 10 reduces the duty cycle of the pulse width modulation command, decreases the output frequency of the frequency converter, and reduces the rotational angular velocity of the screw conveyor until the cumulative discharge mass of high-energy lipid microparticles, polypeptide protein powder, and carbohydrate matrix reaches their respective predetermined weight ratio settings.

[0022] The acquired nutrient components are poured into a homogenizer 20 for mixing, and purified water is added to adjust the consistency into a viscous slurry. The liquid-to-solid mass ratio is controlled within the range of 1.2:1 to 1.5:1. This ratio range ensures that the polypeptide macromolecules can fully expand and crosslink in the aqueous phase, while avoiding excessive free water that would unnecessarily prolong the freeze-drying cycle in the subsequent freeze-drying equipment 40. Specifically, a paddle-type stirring rotor is installed inside the homogenizer 20. The main control device 10 outputs a control level to the proportional adjustment solenoid valve on the water injection pipeline, injecting purified water according to the set liquid-to-solid mass ratio. After water injection, the main control device 10 outputs a start signal to the frequency converter of the homogenizer 20, driving the motor to rotate the stirring paddle. The carbohydrate matrix and polypeptide protein powder undergo physical swelling in the aqueous phase. The long chain structure of the polypeptide molecules expands spatially under mechanical shear stress and combines with water molecules to form a continuous hydrated crosslinked network. High-energy lipid microparticles are subjected to radial stretching and compression in the mechanical shear flow field generated by the stirring rotor, dispersing into micron-sized dispersed phase particles. These dispersed phase particles are distributed and physically embedded in a hydrated cross-linked network, forming a viscous slurry.

[0023] During the mixing process, the main control device 10 continuously reads the torque current value of the motor stator coil fed back by the frequency converter of the homogenizer 20. This value has a non-linear correlation with the apparent viscosity coefficient of the viscous slurry. Specifically, this correlation follows the empirical rheological equation. ,in The apparent viscosity coefficient is... This represents the real-time stator coil torque current value. The unloaded excitation current constant and the rheological index are given. The coefficient of performance is calibrated to be 1.4 to 1.6, representing the fluid consistency coefficient. The judgment process specifically includes (its units of measurement are specifically defined as follows) (To compensate for the dimensional balance of the rheological current equivalent model) is calibrated to 0.85 to 1.12 according to the aforementioned liquid-solid ratio.

[0024] Among them, the above-mentioned no-load excitation current constant The specific steps for obtaining the data are as follows: Before injecting each component, the main control device 10 controls the homogenizer 20 to run continuously for 3 minutes at the set rated mixing speed under no-load conditions, and synchronously records the average value of the steady-state stator coil torque current fed back by the frequency converter during this period, and solidifies this measured average value as a constant. It is stored in the main control device 10 and participates in the real-time solution calculation of the subsequent apparent viscosity coefficient equation.

[0025] The main control device 10 performs sliding time window averaging on the current value, with the duration of each sliding time window set to 5 seconds. When the average current variation coefficient within three consecutive sliding time windows is lower than the set 2.0% control threshold, it is determined that the fluid mixing state has reached macroscopic homogeneity, and the main control device 10 outputs a stop signal to interrupt the operation of the stirring motor.

[0026] During the fluid turbulence and shearing process caused by stirring, ambient air is drawn into the viscous slurry below the surface. Due to the specific apparent viscosity of the viscous slurry system, the drawn-in air molecules are constrained by fluid resistance and trapped inside the fluid, forming free air clusters. To prevent the gas-phase cavity structure from being destroyed by volume expansion during the subsequent negative pressure dehydration process, the viscous slurry is subjected to microbubble removal treatment using an ultrasonic component 30 to eliminate the trapped free air clusters, resulting in the initial paste.

[0027] Specifically, piezoelectric ceramic transducers are arrayed on the outer shell surface of the homogenizer 20. The main control device 10 sends an enable signal to the ultrasonic generator of the ultrasonic component 30, with the specific resonant frequency set to the low-frequency, high-energy cavitation band of 20kHz to 28kHz. The piezoelectric ceramic transducers convert the alternating electrical signal into a mechanical wave of the same frequency based on the inverse piezoelectric effect. This mechanical longitudinal wave penetrates through the container wall and enters the viscous slurry interior, establishing an alternating acoustic pressure field. Free air masses inside the fluid expand in volume during the negative pressure half-cycle of the acoustic field and contract in volume during the positive pressure half-cycle. During the periodic oscillation of volume, adjacent free air masses drift directionally and merge at the physical interface. The equivalent geometric radius of the merged air masses increases. When the buoyancy of the liquid on the air mass exceeds the viscous resistance exerted by the surrounding fluid, the air mass moves upward within the fluid to the gas-liquid separation surface, where the liquid film of the air mass ruptures and discharges the internal gas into the external space. After a preset degassing time period (set to 5 to 8 minutes), the free air clusters encased inside the fluid are completely removed using the ultrasonic component 30, resulting in the initial paste having homogeneous and dense physical characteristics.

[0028] After obtaining the initial paste, the system lays it in a heat-conducting metal tray and places it horizontally on the surface of the heated shelf 44 in the main compartment of the freeze-drying equipment 40. The main control device 10 controls the freeze-drying equipment 40 to pre-freeze the initial paste, causing it to solidify into a pre-frozen solid. This pre-freezing step specifically includes: controlling the operation of the refrigeration compressor unit 41 located at the bottom of the freeze-drying equipment 40 to gradually reduce the surface temperature of the heated shelf 44 at a fixed cooling rate. Specifically, the refrigeration compressor unit 41 compresses the refrigerant, causing it to condense and dissipate heat through the condenser, turning it into a liquid state. The main control device 10 outputs an analog voltage signal to the electronic expansion valve on the refrigerant circulation pipeline according to preset cooling program parameters, adjusting the throttling flow cross-sectional area of ​​the electronic expansion valve. After throttling, the refrigerant enters the heat exchanger inside the heated shelf 44 for evaporation and heat absorption, thereby reducing the surface temperature of the heated shelf 44. The main control device 10 adjusts the opening of the electronic expansion valve through feedback to gradually reduce the surface temperature of the heating shelf 44 at a fixed cooling rate (limited to 0.5℃ / min to 1.2℃ / min in this embodiment to promote the formation of a uniform and fine microscopic ice crystal network inside). This fixed cooling rate control logic makes the temperature of the heating shelf 44 decrease linearly, maintaining a unidirectional heat flow gradient from the bottom of the tray to the initial paste medium.

[0029] During this cooling and heat transfer process, a probe thermocouple 46 inserted into the geometric center of the initial paste continuously feeds back the core temperature value, monitoring the thermodynamic trajectory of the core temperature as it decreases to the freezing point. The initial paste has a relatively long physical path for heat conduction at its geometric center coordinates within the tray. When the probe thermocouple 46 contacts this coordinate position, it generates a thermoelectric potential signal corresponding to the local temperature. The analog acquisition channel of the main control device 10 performs cold junction temperature compensation, signal gain amplification, and low-pass filtering on the thermoelectric potential signal, generating a continuous core temperature value sequence in the time domain after analog-to-digital conversion. As the local temperature decreases to the nucleation threshold, water molecules in the system recombine and arrange themselves into a solid ice crystal network, releasing the latent heat of phase change crystallization. Part of the latent heat offsets the cooling capacity of the heating shelf 44, causing the core temperature value fed back by the probe thermocouple 46 to exhibit a phased heat release plateau region on the time curve. The computing unit of the main control device 10 performs first-order finite difference calculations on the core temperature value sequence to extract the temperature change rate. When the first derivative changes from a plateau value and stabilizes at a negative parameter, the latent heat release stage of crystallization is considered to have ended, and the core temperature continues to decrease as the internal environment cools down.

[0030] When the core temperature value fed back by the insertion probe thermocouple 46 decreases to the target supercooling limit, the refrigeration compressor unit 41 continues to operate until the initial paste is completely solidified. The parameter of the target supercooling limit is set as an absolute temperature coordinate value 3°C to 5°C lower than the eutectic point temperature of the current paste system (pre-determined by resistance method as -22°C to -24°C for this high-fat material). When the core temperature reaches this limit, the main control device 10 stops the downward control logic of setting the cooling rate and outputs a constant frequency operation command to the refrigeration compressor unit 41 to maintain its operation under the current conditions. The preset time span for this constant temperature holding process is set to 120 minutes to 150 minutes in this embodiment, so that the initial paste spatial grid achieves thermodynamic equilibrium and solidifies, forming a pre-frozen solid with a uniformly distributed internal ice crystal structure.

[0031] After the pre-frozen solid is formed, the air inside the freeze-drying equipment 40 is evacuated to create a vacuum. The heating shelf 44 and the cold trap assembly 43 are then activated to enter the main sublimation stage, causing the ice crystals in the pre-frozen solid to sublimate into water vapor. This sublimation stage specifically includes: turning on the multi-stage rotary vane vacuum pump group 42 to extract the atmospheric pressure air accumulated inside the freeze-drying equipment 40, so that the internal absolute pressure is reduced to below the calibrated working vacuum level; and turning on the cold trap assembly 43 to condense the free water vapor generated by the sublimation of ice crystals into a solid ice layer to prevent water vapor from flowing back and eroding the pre-frozen solid.

[0032] Specifically, the main control device 10 outputs a start level to the vacuum control cabinet connected in series with the main exhaust channel 50 of the freeze-drying main chamber, activating the multi-stage rotary vane vacuum pump group 42. The rotor vanes of the multi-stage rotary vane vacuum pump group 42 extract the atmospheric pressure air accumulated inside the freeze-drying equipment 40 and discharge it to the external environment. The absolute pressure vacuum gauge 45 configured on the side wall of the main chamber converts the internal gas static pressure into a corresponding voltage signal, which the main control device 10 collects and converts into an absolute pressure value. When the internal absolute pressure drops below the calibrated working vacuum level and remains in a steady state, the internal pressure of the chamber is within the working pressure limit corresponding to the current temperature of the pre-frozen solid.

[0033] Simultaneously, the main control device 10 activates the cold trap assembly 43, and the refrigerant evaporates within the condenser coil of the cold trap assembly 43, reducing the physical temperature of the condenser coil surface. The main control device 10 connects the solid-state relay of the heating shelf 44 circuit, and the heat transfer medium flows through the electric heater and circulates inside the heating shelf 44, inputting conductive heat flux to the bottom surface of the pre-frozen solid. This external heat flux is used to compensate for the latent heat of phase change required when solid ice crystals transform into free water vapor. Under the calibrated working vacuum, the ice crystals inside the pre-frozen solid undergo a solid-gas phase change, causing the ice crystals inside the pre-frozen solid to sublimate into water vapor. Driven by the concentration gradient and the pressure difference between the main compartment and the cold trap assembly 43, the generated gaseous water vapor molecules detach from the material matrix and diffuse outward. When the free water vapor molecules reach the cold trap area and contact the surface of the condenser coil, a sublimation phase change occurs, condensing the free water vapor generated by the sublimation of ice crystals into a solid ice layer adhering to the tube wall. The cold trap assembly 43 captures water vapor pressure gradient along the main exhaust channel 50 path, providing the power to continuously draw water vapor outward, preventing backflow caused by water vapor accumulation in the compartment, thereby preventing water vapor backflow from eroding the pre-frozen solid external porous skeleton.

[0034] As the main sublimation interface recedes inward, the outer region where the pre-frozen solid undergoes sublimation transforms into a porous, dry matrix layer containing micropores. The gaseous water vapor molecules generated deep within this layer experience hydrodynamic mass transfer resistance as they escape through these micropore channels. For example... Figure 4As shown, during the main sublimation stage, the main exhaust channel 50 is briefly closed at set time intervals to calculate the absolute pressure rise slope during the sealed period. This calculation step specifically includes: controlling the isolation butterfly valve 51 located at the main exhaust channel 50 to close via the main control device 10, cutting off the exhaust circuit; recording the dynamic growth trajectory of the ambient absolute pressure within a specified number of seconds, and extracting the rise rate obtained after linear fitting as the absolute pressure rise slope; immediately reopening the isolation butterfly valve 51 after extraction to restore normal evacuation. Specifically, the timing module built into the main control device 10 triggers control commands at set time intervals (configured to execute once every 45 to 60 minutes). The main control device 10 outputs a control level to the pneumatic actuator electromagnetic reversing valve at the main exhaust channel 50, controlling the isolation butterfly valve 51 to close and cut off the exhaust circuit. The dry main compartment is transformed into a closed system with a constant physical volume. During the closure of the isolation butterfly valve 51, the heating shelf 44 maintains a preset heat power output, and the deep ice crystals of the pre-frozen solid absorb heat and continue to sublimate into gaseous water molecules. The newly added water vapor molecules accumulate in the sealed main chamber, increasing the total amount of the mixed gas. Under constant volume constraints, the increase in internal gas pressure causes the absolute atmospheric pressure to rise unidirectionally.

[0035] During the closure of the isolation butterfly valve 51, the main control device 10 continuously records the dynamic increase trajectory of the ambient absolute pressure fed back by the absolute pressure vacuum gauge 45 within a specified number of seconds (set to 15 to 20 seconds) at a set hardware sampling rate. This specified number of seconds ensures that a sufficient number of discrete pressure data points are extracted for univariate linear regression fitting, while effectively preventing the deep ice crystals from melting beyond the limit due to excessive sealing time of the main exhaust channel 50. The digital processor of the main control device 10 performs univariate linear regression on the collected discrete pressure data point set, calculates the parameters of the fitted straight line using the least squares algorithm, and extracts the rise rate obtained after linear fitting as the absolute pressure rise slope. This slope value maps the net evaporation mass flow rate of water molecules penetrating the porous matrix and escaping into the chamber per unit time. After the calculation and extraction are completed, the isolation butterfly valve 51 is immediately reopened to restore the normal evacuation state. The main control device 10 cancels the control signal of the electromagnetic reversing valve, and the pneumatic actuator resets and opens the isolation butterfly valve 51. The main compartment re-establishes fluid communication with the multi-stage rotary vane vacuum pump group 42 pipeline, and the water vapor accumulated in the compartment is discharged under the pressure difference, and the ambient absolute pressure drops back to the working vacuum range.

[0036] The main control device 10 performs a logical comparison between the extracted absolute pressure rise slope value and the reference boundary value stored in the memory. Based on the phase change thermodynamic model and the ideal gas law, the system calculates the reference boundary value. The specific control equations are as follows: Theoretical mass rate of water formation from gaseous state: ; Ideal pressure increase rate: ; Reference boundary values: ; In the formula, The effective net heat power of the heating shelf 44; The latent heat of sublimation of ice; It is the ideal gas constant; The absolute temperature of the main compartment; The molar mass of water vapor; Net volume of the main cabin; The reduction factor is calibrated to a range of 0.75 to 0.85. This dimensionless reduction range absorbs the inherent physical attenuation caused by the static leakage rate of the pipeline network and the flow resistance of the normal porous skeleton foundation.

[0037] The effective net heat power of the heating shelf 44 The exact method for obtaining this information is through online dynamic derivation by the main control device 10. The specific mathematical formula for the derivation is as follows: ; In the formula, The rated total electrical power currently output from the main control device 10 to the solid-state relay; The electrothermal conversion efficiency constant is calibrated to 0.92 to 0.95 based on hardware attributes; The overall heat transfer coefficient of the outer wall of the main compartment of the freeze-drying equipment 40 was pre-calibrated through the no-load thermal balance test when the equipment left the factory. The surface area for heat dissipation in the main compartment; and These are the equivalent temperature of the inner wall of the main chamber of the freeze-drying equipment 40 and the absolute temperature of the external environment collected by the sensor, respectively.

[0038] The specific operational derivation steps of the no-load thermal balance experiment are as follows: In a clean, no-material state within the main chamber of the freeze-drying equipment 40, the multi-stage rotary vane vacuum pump group 42 is started to pump the internal air pressure to and maintain it at the 20Pa limit. The heating shelf 44 is controlled to operate at full power to raise the temperature and maintain it at the calibrated test temperature (40℃) continuously. When the average surface temperature fed back by the multi-point thermocouples arranged on the outer wall of the chamber fluctuates by less than 0.5℃ within a continuous 30-minute time window, the system is deemed to have reached the steady-state thermal balance limit for heat dissipation. The main control device 10 synchronously extracts the steady-state average electrical power maintained at this constant temperature output. By reverse calculation of the formula The specific comprehensive heat transfer coefficient value is obtained by solving and then fixed as a constant and written into a non-volatile memory cell.

[0039] The equivalent temperature of the inner wall Dynamic calculations are required via the main control device 10. Since the high-lipid, viscous paste of the special energy bar has relatively fixed heat transfer characteristics under specific conditions, this system pre-establishes a spatial distribution mapping table of the temperature gradient from the material core to the inner wall of the chamber based on unsteady-state thermal conductivity differential equations. During real-time thermodynamic calculations, the main control device 10 uses probe-type thermocouples 46 to feed back the core temperature value. Using the origin as the input, after compensating for the thermal resistance of the porous skeleton and the vacuum convection thermal resistance inside the cabin through table lookup calculations, the equivalent temperature of the inner wall is dynamically calculated and substituted into the equation for solution.

[0040] Specifically, the unsteady-state heat conduction differential equation adopts a one-dimensional infinite flat plate heat conduction model, and its basic mathematical expression is: ; In the formula, The internal temperature of the material. For time, The coordinates are for heat transfer along the thickness of the material. The apparent thermal diffusivity of the porous matrix.

[0041] Considering the limitations of the real-time edge computing power of the main control device 10, the temperature gradient spatial distribution mapping table is not solved in real time during operation for partial differential equations. Instead, it is a pre-generated static constant matrix based on the discretized numerical simulation of the aforementioned partial differential equations combined with offline multi-point thermocouple temperature measurement experiments using standard samples. This mapping table uses the core temperature feedback from the probe-type thermocouple 46 as the basis. (The calibration range is -30°C to 40°C, with a distance of 5°C from the set point) and the real-time absolute pressure of the main compartment of the freeze-drying equipment. (The calibration range is 10Pa to 1500Pa, divided into 5 nodes logarithmically.) This serves as a two-dimensional addressing index, directly outputting the corresponding compensated temperature difference between the inner and outer walls. As a specific implementation boundary of the correspondence table, when -20°C and When the working vacuum is 20 Pa, the mapping table calls the compensated temperature difference. The absolute pressure is 4.2°C; Rise to 1000Pa pulse high voltage and When the temperature rises to 35°C, the function is activated. The temperature is 1.8°C. The main control device 10 directly connects to... Obtain the equivalent temperature of the inner wall.

[0042] After determining that the absolute pressure rise slope is lower than the benchmark boundary value, the main control device 10 extracts and calculates the attenuation weight. The specific mathematical mapping rules are as follows: ,in This refers to the measured absolute pressure rise slope within a specified number of seconds. Subsequently, the main control device 10 follows the formula... Determine the new control parameters, among which This is the currently set initial heating duty cycle. This is the updated target duty cycle. The main control device 10 will calculate the... The signal is sent to the solid-state relay for pulse width modulation to establish a logical correspondence, dynamically intercepting excess heat flux that induces deep ice crystals to melt beyond the phase transition point. When the main control device 10 determines that the absolute pressure rise slope is lower than the reference boundary value, it indicates that the effective physical cross-sectional area of ​​the micropores in the porous matrix skeleton has decreased, and the flow resistance of deep gas transfer has increased. In this state, if the set heating power continues to be maintained, the input heat that has not been consumed by the latent heat of sublimation will accumulate at the ice crystal physical interface, causing the deep temperature to rise. The main control device 10 accordingly reduces the output power of the heating shelf 44. The main control device 10 sends a control command to the solid-state relay to reduce the duty cycle, decrease the heater conduction time ratio, reduce the heat load transferred to the heat transfer medium, and suppress the heating rate inside the material.

[0043] To clear the micro-channels that cause flow resistance, the system injects cold inert gas into the freeze-drying equipment 40 while reducing the power. Then, it controls the isolation butterfly valve 51 located at the main exhaust channel 50 to fully open, resulting in a sudden drop in gas pressure. This clearing step specifically includes: opening the back pressure compensation valve 61 on the intake pipe 60 to introduce low-temperature high-purity nitrogen gas stored in the external gas source connected to the freeze-drying equipment 40 into the freeze-drying equipment 40, raising the internal static pressure to squeeze the outer blocking layer that has already formed; controlling the isolation butterfly valve 51 located at the main exhaust channel 50 to fully open to rapidly reduce the pressure, and using a preset multiple of pressure difference to effectively discharge the saturated water vapor that is blocked deep in the micro-pores.

[0044] Specifically, the main control device 10 outputs an opening signal to the back pressure compensation valve 61 of the air intake pipe 60, introducing low-temperature high-purity nitrogen stored in the external air source into the freeze-drying device 40. The injection of low-temperature high-purity nitrogen limits the introduction of additional thermodynamic sensible heat into the system. As the high-purity nitrogen enters the main chamber, the absolute pressure of the internal space increases. The increased pressure creates positive pressure mechanical stress on the surface of the porous matrix, raising the internal static pressure to compress the outer barrier layer. Under the action of the static pressure difference, nitrogen physically seeps into the micropores of the porous matrix and mixes with the saturated water vapor retained in the channels. The main control device 10 monitors the internal absolute pressure, and when the pressure value reaches a preset high-pressure threshold, it outputs a control command to the pneumatic actuator to fully open the isolation butterfly valve 51. The isolation butterfly valve 51 is fully open, establishing a connection between the main chamber filled with higher-pressure gas and the main exhaust channel 50, which maintains a low-pressure state, forming a pressure-reducing flow field boundary. The mixed gas, infiltrated into the confined space of the pre-frozen solid's micropores, undergoes fluid expansion when the external pressure decreases. The expanded gas flow is directionally discharged outward along the pore channels. The discharged gas flow generates aerodynamic drag on the inner wall of the micropores, breaking up and stripping away the aggregated saturated water vapor within the blind ends of the micropores, and using pressure difference expansion to clear the water vapor escape channels. The preset high-pressure threshold achieved by injecting cold, high-purity nitrogen is rigidly constrained within the range of 500 Pa to 800 Pa. This upper limit parameter is limited by the three-dimensional compressive yield strength stress of the special energy bar's polypeptide cross-linked network after solidification.

[0045] In conjunction with the normal operating vacuum maintained between 20 Pa and 50 Pa, the isolation butterfly valve 51 instantaneously operates throughout its entire stroke, creating a pressure difference of 15 to 40 times the preset multiple at the flow field geometry interface. When the pressure drop across the pore exceeds the critical pressure ratio of the diatomic gas, the depressurized expansion flow generates a local sonic congestion flow at the throat of the microscopic confined pore. The shear force of the sonic shock wave effectively removes the blocked saturated water vapor, while the aforementioned peak aerodynamic load is limited below the critical point of mechanical fracture of the skeleton, avoiding pore collapse and tearing of the porous matrix. After executing this command sequence, the main control device 10 resumes the normal operating state of the main sublimation stage and triggers the valve closing calculation absolute pressure rise slope control logic again according to the set cycle. Until the newly acquired absolute pressure rise slope recovers to a value not lower than the reference boundary value, the main control device 10 releases the power limitation constraint on the heating shelf 44 and restores the initially set heating control parameters.

[0046] When the free ice crystals inside the pre-frozen solid have undergone a basic phase transition and are exhausted, the dehydration mechanism changes from the sublimation mechanism of free water to the surface-bound hydrolysis and adsorption mechanism. For example... Figure 5As shown, the system enters the analytical dehydration stage, continuously acquiring the moisture capture rate of the cold trap assembly 43. This calculation step specifically includes: monitoring the frost increment data on the surface of the cold trap assembly 43; calculating the sublimated water vapor mass migration rate based on the frost increment data within a set calculation period; and using the sublimated water vapor mass migration rate as the moisture capture rate characterizing the dehydration progress. Specifically, the condenser coil and fluid guide shroud of the cold trap assembly 43 are connected to the weighing sensor array 70 through a supporting rigid structure. The main control device 10 monitors the frost increment data on the surface of the cold trap assembly 43. In the closed freeze-drying fluid pipeline system, the mass of the solid frost layer added to the surface of the cold trap coil is equivalently mapped to the mass of water vapor desorbed and escaped from the main drying chamber at the same time. The strain voltage signal output by the weighing sensor array 70 is amplified at the front end and processed by a digital filter for noise reduction to generate continuous baseline data representing the current total mass of frost. Based on the frost increment data within the set measurement period, the main control device 10 performs a first-order difference calculation in the time dimension to convert the mass increment into a water vapor capture rate per unit time, and calculates the sublimated water vapor mass migration rate. The main control device 10 uses the sublimated water vapor mass migration rate as the moisture capture rate characterizing the dehydration progress and writes it into the built-in storage unit.

[0047] Deeply bound water is adsorbed onto the surface of the porous matrix framework through physical interactions such as hydrogen bonding, and its desorption requires activation energy. The main control device 10 periodically compares the water capture rate with a pre-stored lower limit value. When the water capture rate is lower than the lower limit value, it indicates that the low-adsorption-energy bound water in the surface layer and macroscopic channels has been desorbed and discharged. If the output power of the heating shelf 44 is increased at this time to accelerate dehydration, the heat will accumulate at the bottom of the material due to the reduced thermal conductivity of the porous framework after dehydration, causing localized heating and crossing the thermally induced deformation boundary of the material components. Based on this parameter status, the main control device 10 locks the output temperature of the heating shelf 44 and initiates an alternating suction and desorption step, alternately raising and lowering the absolute pressure inside the freeze-drying device 40 to force the deep bound water to desorb and separate. This alternating suction and desorption step specifically includes: stopping the heating shelf 44 from continuing to heat up, so that the internal environment of the freeze-drying device 40 is maintained within a set safe thermodynamic range; closing the main exhaust channel 50 and introducing heat-conducting medium gas into the freeze-drying device 40, so that the internal absolute pressure climbs to the pulse high pressure value, causing the heat-conducting medium gas to penetrate into the deep interior for heat transfer; after maintaining the target heat transfer time, starting the vacuum extraction action at full speed, so that the internal absolute pressure drops rapidly to the lower limit of the ultimate vacuum value, and the deep bound water is forced to desorb and separate through physical negative pressure.

[0048] The pulsed high pressure value reached during pressurization is locked in the range of 1000Pa to 1500Pa. This static pressure environment forces the Knudsen number of gas molecules in the micropores to decrease to below the 0.01 limit. The spatial flow state is forced to transition from inefficient molecular free diffusion to continuous viscous convection heat transfer, which multiplies the gas-solid deep heat transfer coefficient.

[0049] Target heat transfer duration The calculation model is derived based on the Fourier number of unsteady heat conduction: ; In the formula, This is the characteristic distance from the geometric center of the sample to its surface; The apparent thermal diffusivity of the porous matrix. For the high-energy lipid and polypeptide protein composite initial paste provided by this invention, the apparent thermal diffusivity of the porous matrix after curing is... The specific range of values ​​is defined as follows The precise method for obtaining this parameter is as follows: Offline physical measurements of prefabricated porous dried skeleton samples of the same composition are performed in a vacuum chamber with an ambient pressure of 20 Pa to 50 Pa using a flash thermal conductivity meter. The average value of the measurements is extracted and written as a constant into the storage unit of the main control device 10, ensuring that the Fourier number extrapolation model has a clear data benchmark. This time limit is typically set to 60 to 90 seconds to ensure that constant-volume heat transfer is immediately interrupted as soon as the convective heat wavefront touches the deep bound water sites, preventing excessive sensible heat accumulation in the outer support skeleton. The subsequent vacuum limit reached by pumping is calibrated to 5 Pa to 10 Pa, closely adhering to the current system network's no-load operating baseline. This instantaneous establishment of a steep chemical potential and pressure gradient spanning two orders of magnitude overcomes the hydrogen bonding forces upon which deep bound water depends.

[0050] Specifically, the main control device 10 limits the duty cycle of the control pulse output to the solid-state relay, stopping the heating shelf 44 from further heating and locking its surface temperature parameter at the currently set equilibrium value. This control operation maintains the internal environment of the freeze-drying equipment 40 within the set safe thermodynamic range, ensuring that the solid-phase support network is within the set temperature boundary and avoiding thermoplastic softening. The calibration lower limit value that triggers the above-mentioned analytical dehydration control action is taken as 4% to 5% of the absolute peak water capture rate recorded by the cold trap component 43 during the vigorous sublimation stage. This attenuation indicates that the dehydration kinetics are fully controlled by the desorption activation energy barrier of bound water. The upper limit of the set safe thermodynamic range locked by the system directly calls the onset melting point of the internal high-energy lipid particles pre-calibrated by the differential scanning calorimeter and offsets it downward by 3°C to 5°C to establish an absolute safety line of 35°C, preventing high-energy oils from crossing the solid-liquid phase transition line and causing liquid phase free penetration and oxidative deterioration from the thermodynamic source.

[0051] Subsequently, the main control device 10 sends a level command to the pneumatic actuator to close the isolation butterfly valve 51 at the main exhaust channel 50, transforming the main compartment into a constant-volume enclosed space. The main control device 10 opens the back pressure compensation valve 61 of the air intake pipe 60, introducing a heat transfer medium gas into the freeze-drying equipment 40. The heat transfer medium gas is high-purity nitrogen gas after filtration and dehumidification. With the continuous injection of high-purity nitrogen gas, the gas molecule density in the compartment increases, causing the internal absolute pressure to rise to a pulse high-pressure value. The increase in pressure leads to a shortening of the mean free path of the gas molecules in the compartment, and the fluid flow characteristics transform into continuous viscous convection, thereby increasing the gas space heat transfer coefficient. Under the impetus of the pressure gradient, the heat transfer medium gas penetrates to the deep interior to transfer heat. Gas molecules penetrate deep into the micropores, transferring sensible heat to the solid-phase framework and adsorbed bound water molecules deep within the pores through convection collisions.

[0052] After maintaining the target heat transfer duration, deep-bound water molecules absorb the heat conducted by the gas, and some water molecules desorb and transform into free gas. At this time, the main control device 10 cuts off the drive signal of the air intake pipe 60, sends a full-stroke opening control command to the isolation butterfly valve 51, and starts the multi-stage rotary vane vacuum pump group 42 to perform evacuation. The constant-volume chamber is reconnected to the multi-stage rotary vane vacuum pump group 42, which maintains full-load evacuation operation, causing the mixed gas in the chamber to undergo adiabatic volume expansion, causing the internal absolute pressure to drop rapidly to the lower limit of the ultimate vacuum. The outward low-pressure gradient causes the gas inside the pores to flow outward along the connecting channels to form an exhaust fluid, and the exhaust flow generates a drag force on the surface of the channels. This force, in conjunction with the external vacuum boundary conditions, forces the deep-bound water to desorb and separate its adsorption sites through physical negative pressure. The desorbed water molecules escape from the porous matrix system with the exhaust flow field and are transported to the collection system.

[0053] like Figure 6 As shown, after the absolute pressure inside the freeze-drying equipment 40 is alternately raised and lowered, a cycle end determination process is entered to assess the dehydration status of the material. The determination process specifically includes: repeatedly executing the alternating suction and suction steps, and simultaneously monitoring the absolute humidity value inside the main exhaust channel 50; when the absolute humidity value is lower than the set endpoint boundary for multiple consecutive detection cycles and remains stable, the cycle action is interrupted, the final drying is determined to be completed, and the vacuum chamber is broken and the material is removed.

[0054] The endpoint boundary is established based on the attenuation parameter of transmitted light intensity from the naturally residual water vapor in the pipeline network under no-load pre-operation conditions. The endpoint boundary is then truncated at the baseline. and steady-state variation coefficient The statistical model is as follows: ; ; In the formula, and These are the arithmetic mean and standard deviation of absolute humidity under no-load conditions, respectively. and These represent the standard deviation and average value of the absolute humidity response peak extreme values ​​within a continuous detection period.

[0055] The judgment logic for multiple consecutive detection cycles stipulates that the main control device independently buffers the extreme values ​​of the absolute humidity response peaks during the initial stage of three consecutive depressurization exhaust cycles. When all three sets of peaks decrease to within the set endpoint boundary, and the coefficient of variation of adjacent peak extreme values ​​converges to within 2%, the system is considered to have reached a stable state. This mathematical and statistical closed-loop objectively verifies that the deep desorption driving potential energy within the porous physical system has tended to balance, and the microscopic heat and mass transfer process has reached the set target drying endpoint.

[0056] Specifically, the main control device 10 repeatedly executes the pressurization and depressurization cycle in the alternating suction and descaling steps according to the predetermined control logic, and simultaneously monitors the absolute humidity value in the main exhaust channel 50. A gas analysis probe 80 based on tunable semiconductor laser absorption spectroscopy technology is installed at the flange of the main exhaust channel 50. A specific wavelength laser emitted by the probe passes through the cross-section of the exhaust flow field, and gaseous water molecules in the flow field absorb the photon energy of the corresponding frequency band, causing energy level transitions. To accurately extract the absorption characteristics of water molecules and eliminate cross-interference in the background exhaust flow field containing high-purity nitrogen, the center wavelength of the specific wavelength laser is specifically selected as 1392.53 nm. This wavelength corresponds to gaseous water molecules... The vibrational band exhibits strong absorption spectral lines, and nitrogen and conventional oligosaccharide volatiles show no significant absorption peaks within this frequency band. In practical implementation, the distributed feedback (DFB) laser integrated within the gas analysis probe 80, driven by the temperature control and current modulation module, performs high-frequency micro-scanning in the 1392nm to 1393nm range to obtain the complete single absorption spectral profile of water molecules. Choosing this near-infrared band not only utilizes mature device technology and eliminates the need for cryogenic packaging, but also provides sufficient spectral line intensity coefficients to ensure the signal-to-noise ratio for the following absolute humidity calculations under low-pressure conditions. The receiver detector converts the transmitted light intensity attenuation parameter into an electrical signal. The main control device 10 calculates the molar concentration of water vapor molecules in the exhaust section based on the transmitted light intensity attenuation ratio and real-time pressure and temperature parameters of the flow field, generating the corresponding absolute humidity value at the specified time point.

[0057] Specifically, the calculation of the molar concentration parameter is based on the integral formula of the modified Beer-Lambert law: ; In the formula, The attenuation ratio of transmitted light intensity converted by the detector at the receiving end is denoted as , where This represents the real-time transmitted light intensity at the receiving end. The initial emitted light intensity of the detector; the equivalent absorption coefficient of water molecules constrained by the flow field physics. The basic characteristic spectral line intensities are retrieved by the HITRAN spectral database module pre-set in the main control device 10, and then the unit conversion and numerical preprocessing are performed in combination with the real-time flow field status to obtain the values. The real-time absolute temperature of the exhaust flow field; The real-time absolute pressure of the flow field; The known effective optical path length calibrated for the gas analysis probe 80.

[0058] Determine the water vapor concentration Subsequently, the system directly converts the mixed gas into absolute humidity values ​​at the corresponding time points based on the equation of state. In the initial stage of each depressurization expansion and vacuuming phase, the escape of excited moisture from the pores forms an absolute humidity response peak. As the alternating suction and desorption cycle increases, the number of water molecules available for physical desorption from the pores gradually decreases. The main control device 10 extracts continuously sampled absolute humidity peak data and performs coefficient of variation comparison verification. When the absolute humidity value remains below the set endpoint boundary for multiple consecutive detection cycles and remains stable, it indicates that the residual moisture state in the porous system has reached the physical desorption equilibrium limit. The main control device 10 issues a control command to interrupt the cycle, stopping the operation and output of the refrigeration compressor unit 41 and the multi-stage rotary vane vacuum pump unit 42, determining that final drying is complete. The main control device 10 controls the pressure-stabilizing bypass valve to gently inject atmospheric pressure gas into the drying chamber, eliminating the pressure difference between the inside and outside of the pipeline network, executing the mechanical door opening operation, breaking the vacuum, and producing a molded special energy bar.

[0059] This embodiment further discloses a special energy bar, which is prepared by the intelligent freeze-drying method based on multi-parameter feedback described in any of the preceding embodiments. The special energy bar has an interconnected multidimensional pressure-resistant microporous network inside, and high-energy lipid microparticles that maintain a solid physical conformation are deeply sealed inside.

[0060] Specifically, the special energy bar possesses an interconnected multidimensional, pressure-resistant microporous network. This three-dimensional network structure is formed based on the in-situ nucleation and crystallization of water molecules forming a solid ice crystal network within the initial material during the pre-freezing stage. In the subsequent main sublimation and desorption stages, the temperature output of the heating shelf 44 is dynamically adjusted through a feedback mechanism controlling physical parameters such as the absolute pressure rise slope. Combined with the fluid dynamic adjustment process of alternating increases and decreases in ambient air pressure, the material avoids plastic viscous flow deformation and pore collapse caused by heat flow within the solid-phase cross-linked framework during the moisture separation and escape cycle. The polypeptide cross-linked segments and the carbohydrate solid support framework solidify and solidify into a porous network with spatial porosity and pore connectivity characteristics while maintaining the original physical boundaries of the external dimensions. In terms of mechanical properties, when this solid-phase formed network structure is subjected to externally applied mechanical loads and physical vibration stresses, the mechanical stress at local stress points can be transmitted and dispersed along the three-dimensional spatial framework nodes into the matrix, exhibiting stable compressive rigidity strength indicators. Meanwhile, the interconnected three-dimensional micro-channels form a capillary permeation network model. During the rehydration process, driven by the hydrodynamic force of the Laplace tension on the surface of the micro-pore wall, the rehydration medium can penetrate and wet the deeper layers along the internal pores, promoting the hydration of the cross-linked solid skeleton.

[0061] Furthermore, deep within the wall layers of the aforementioned multidimensional pressure-resistant microporous network, the special energy bar deeply encapsulates high-energy lipid microparticles that maintain a solid physical conformation. This micro-level closed encapsulation structure benefits from the physical upper limit parameter locking constraint applied to the temperature control of the heating shelf 44 during the deep moisture stripping stage, and the convective heat transfer model implemented by introducing a high-purity heat-conducting medium gas. Within the set thermodynamic temperature control range, the local ambient temperature of each high-energy lipid microparticle distributed at the center of the material and deep within the micropores is maintained below the solid-liquid phase transition melting limit parameters of each chemical component. The spatial conformation of the high-energy lipid molecules does not undergo thermal degradation or oxidative chain breakage, and the phase structure exhibits a stable discrete physical distribution state of solid-phase microparticles, without liquid wetting migration or phase fusion. The high-energy solid-phase microparticles, maintaining their original physicochemical parameters, are in-situ physically encapsulated by the dehydrated and shaped polypeptide cross-linked wall layer network, anchored and embedded within the supporting micro-cross-linked architecture. This microscopic solid-state encapsulation network forms a spatial physical isolation interface, blocking the reaction path of direct physical contact between high-energy lipid particles and external environmental media, and ensuring that the biochemical and physicochemical parameters of the product remain stable during a specific storage period.

[0062] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A smart freeze-drying preparation method based on multi-parameter feedback, characterized in that, Include: Provide initial paste; The freeze-drying equipment is controlled to pre-freeze the initial paste, causing the initial paste to solidify into a pre-frozen solid; The freeze-drying equipment is evacuated to create a vacuum, and the heating shelf and cold trap assembly are activated to enter the main sublimation stage, causing the ice crystals in the pre-frozen solid to sublimate into water vapor. During the main sublimation stage, the main exhaust channel is briefly closed at set time intervals, and the absolute pressure rise slope during the closed period is calculated. When the absolute pressure rise slope is lower than the reference boundary value, the output power of the heating shelf is reduced, and cold inert gas is injected into the freeze-drying equipment. Then, the isolation butterfly valve set at the main exhaust channel is fully opened to generate a sudden drop in air pressure. The pressure difference expansion is used to clear the water vapor escape channel until the absolute pressure rise slope recovers to not lower than the reference boundary value. The process then transitions to the dehydration and analysis phase, continuously acquiring the moisture capture rate of the cold trap component. When the moisture capture rate is lower than the calibrated lower limit value, the output temperature of the heating shelf is locked and the alternating suction and extraction step is started, alternatingly raising and lowering the absolute air pressure inside the freeze-drying equipment, causing the deep bound water to be forcibly desorbed and separated, and a special energy bar is produced.

2. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, Before the freeze-drying equipment pre-freezes the initial paste, a batching step is included: High-energy lipid microparticles, polypeptide protein powders, and carbohydrate matrix are obtained according to a predetermined weight ratio. Pour all the obtained nutrient components into a homogenizer and mix them. Add purified water to adjust the consistency into a thick paste. The viscous slurry is subjected to microbubble removal treatment using an ultrasonic component to eliminate the free air clusters trapped inside, thus obtaining the initial paste.

3. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, The freeze-drying equipment is used to pre-freeze the initial paste, and the pre-freezing step specifically includes: The refrigeration compressor unit located at the bottom of the freeze-drying equipment is controlled to operate, and the surface temperature of the heating shelf is gradually reduced at a fixed cooling rate; A probe thermocouple inserted into the geometric center of the initial paste is used to continuously feed back the core temperature value and monitor the thermodynamic change trajectory of the core temperature value as it drops to the freezing point region. When the core temperature drops to the target supercooling limit, the refrigeration compressor unit is kept running until the initial paste is completely solidified.

4. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, The process involves evacuating the internal air of the freeze-drying equipment to create a vacuum, then activating the heating shelf and cold trap assembly to enter the main sublimation stage. This sublimation stage specifically includes: Turn on the multi-stage rotary vane vacuum pump group to extract the atmospheric pressure air accumulated in the freeze-drying equipment, so that the internal absolute air pressure is reduced to below the rated working vacuum level. The cold trap assembly is activated to condense the free water vapor generated by the sublimation of ice crystals into a solid ice layer, preventing water vapor from flowing back and eroding the pre-frozen solid.

5. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, The step of continuously acquiring the moisture capture rate of the cold trap component specifically includes: Monitor the incremental data of frost formation on the surface of the cold trap assembly; Based on the frost increment data within the set calculation period, the sublimated water vapor mass migration rate is calculated. The sublimated water vapor mass migration rate is used as the moisture capture rate to characterize the progress of dehydration.

6. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, The step of briefly closing the main exhaust channel at set time intervals and calculating the absolute pressure rise slope during the sealed period includes: The main control device controls the closure of the isolation butterfly valve located at the main exhaust channel to cut off the exhaust circuit; Record the dynamic growth trajectory of the absolute atmospheric pressure within a specified number of seconds, and extract the rate of increase obtained after linear fitting as the absolute atmospheric pressure rise slope. Once extraction is complete, immediately reopen the isolation butterfly valve to restore normal air extraction.

7. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, The process of injecting cold inert gas into the freeze-drying equipment, followed by fully opening the isolation butterfly valve located at the main exhaust channel to generate a sudden pressure drop, specifically includes the following steps: Open the back pressure compensation valve on the air inlet pipe to introduce the low-temperature high-purity nitrogen gas stored in the external air source connected to the freeze-drying equipment into the freeze-drying equipment, thereby increasing the internal static pressure to compress the outer barrier layer that has been formed. The isolation butterfly valve located at the main exhaust channel is fully opened to rapidly reduce pressure, effectively expelling saturated water vapor that is blocked deep in the micropores by utilizing a preset multiple of pressure difference.

8. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, The alternating suction and withdrawal step involves alternating increases and decreases in the absolute air pressure inside the freeze-drying equipment. This alternating suction and withdrawal step specifically includes: Stop the heating shelf from heating further, so that the internal environment of the freeze-drying equipment is maintained within the set safe thermodynamic range; Close the main exhaust channel and introduce heat-conducting medium gas into the freeze-drying equipment to make the internal absolute pressure rise to the pulse high pressure value, so that the heat-conducting medium gas can penetrate into the deep interior to transfer heat. After maintaining the target heat transfer time, start the vacuum extraction action at full speed to rapidly reduce the internal absolute pressure to the lower limit of the ultimate vacuum value, and force the deep bound water to desorb and separate through physical negative pressure.

9. The intelligent freeze-drying preparation method based on multi-parameter feedback according to claim 1, characterized in that, After alternating increases and decreases in the absolute pressure inside the freeze-drying equipment, the dehydration state of the material is assessed, and the determination process specifically includes: Repeat the alternating suction and suction steps while simultaneously monitoring the absolute humidity value in the main exhaust channel; When the absolute humidity value is below the set endpoint boundary for multiple consecutive detection cycles and remains stable, the cycle is interrupted, the final drying is determined to be complete, and the vacuum chamber is broken and the product is removed.

10. A special energy bar, characterized in that, Prepared by the intelligent freeze-drying preparation method based on multi-parameter feedback as described in any one of claims 1-9; The special energy bar has an interconnected multidimensional pressure-resistant microporous network inside, and high-energy lipid microparticles that maintain a solid physical conformation are deeply sealed inside.

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