Freeze-drying system and method suitable for large-scale rapid freeze-drying

Abstract

In order to solve the problems existing in the prior art, the present invention provides a freeze-drying system suitable for large-scale rapid freeze-drying, comprising: a low-temperature freezer and a vacuum rapid drying system, and the object to be dried is placed in a drying tank. The vacuum rapid drying system comprises: a dehumidifying device, a drying device, a vacuum device and a control system, wherein a first blower blows the external air into the drying chamber of the drying device after dehumidification by the dehumidifying device. The drying chamber of the drying device is connected to the vacuum device and can be evacuated to a negative pressure state by the vacuum device. The drying tank can be placed in the low-temperature freezer and the drying chamber of the drying device, and the drying tank is assembled from a porous far-infrared ceramic plate with a main wavelength of 6-14μm. The present invention is based on the drying tank with a special structure of the present invention, which can realize the freezing of Chinese medicinal materials by placing them in a freezer, significantly reducing the cost of freezing treatment, and at the same time, the drying time is significantly shortened compared with the existing freeze-drying technology.

Description

Technical Field

[0001] The present invention relates to the field of freeze-drying technology, in particular to a freeze-drying system and method suitable for large-scale rapid freeze-drying. Background Art

[0002] Vacuum freeze-drying technology is a novel drying method that freezes water-containing materials into a solid state and then utilizes the sublimation properties of water under low temperature and low pressure conditions to achieve low-temperature dehydration and drying. Because vacuum freeze-drying operates in a low-temperature, low-oxygen environment, most biological reactions are stagnant. In the absence of liquid water during the process, water sublimates directly in a solid state, preserving the material's original structure and shape to the greatest extent possible. The result is a high-quality dried product with both visual and intrinsic qualities.

[0003] Traditional Chinese medicines, especially botanicals, are often dried for storage. Vacuum freeze-drying (hereinafter referred to as freeze-drying) is the preferred drying method for botanicals due to its excellent retention of active ingredients and improved rehydration rate.

[0004] However, the existing freeze-drying technology has the following problems when processing Chinese medicinal materials: 1. The freezing process requires the use of liquid nitrogen for rapid freezing, and the sub-zero environment during the process also needs to rely on liquid nitrogen for temperature control, so the freezing cost is extremely high. 2. Since liquid nitrogen is required to maintain a low-temperature environment, the volume of the processing tank is generally not large, so the amount of Chinese medicinal materials freeze-dried in each batch is not large, which makes it difficult to carry out large-scale processing. 3. The drying process has a long cycle, generally more than ten hours, and a drying time of 2-3 days is common, and the drying efficiency is low. 4. The freeze-drying process of Chinese medicinal materials will cause varying degrees of loss of the content of effective substances in the Chinese medicinal materials. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a freeze-drying system suitable for large-scale rapid freeze-drying, comprising: a low-temperature freezer and a vacuum rapid drying system, wherein the material to be dried is placed in a drying tank. The vacuum rapid drying system comprises: a dehumidification device, a drying device, a vacuum device, and a control system, wherein a first blower blows the outside air into the drying chamber of the drying device after dehumidification by the dehumidification device. The drying chamber of the drying device is connected to the vacuum device and can be evacuated to a negative pressure state by the vacuum device. The drying tank can be placed in the low-temperature freezer and the drying chamber of the drying device, and the drying tank is assembled from porous far-infrared ceramic plates with a main wavelength of 6-14μm.

[0006] The drying device comprises a drying chamber for placing a drying tank, a heater and a cooling system are arranged in the drying chamber, one end of the drying chamber is closed, and the other end is provided with an airtight door.

[0007] The control system is connected to the first blower, vacuum device, heater, and cooling system signals, and performs the following control when vacuum rapid drying is required:

[0008] S1. Control the cooling system and heater to keep the ambient temperature in the drying chamber at the preset temperature.

[0009] S2. Start the vacuum device to reduce the pressure in the drying chamber to 80 mmHg to 120 mmHg and maintain this pressure for 1-5 minutes.

[0010] S3. Control the first blower to blow dry air into the drying chamber to increase the pressure in the drying chamber to 350 mmHg to 370 mmHg, and maintain the pressure for 1-5 minutes through the vacuum device.

[0011] S4. After repeating steps S2 and S3 for a preset number of times or a preset time, the pressure in the drying chamber is restored to room pressure, completing the vacuum drying process.

[0012] Furthermore, the dehumidification device includes an air inlet main pipe connected to the outside, an air outlet main pipe connected to the drying chamber, a dehumidification main pipe connected to the outside, and at least two groups of filtering and dehumidification mechanisms arranged between the air inlet main pipe and the air outlet main pipe and connected to the air inlet main pipe, the air outlet main pipe, and the dehumidification main pipe respectively.

[0013] The dehumidification and filtration mechanism includes an air inlet branch connected to the main air inlet pipe, a dehumidification chamber filled with circulating desiccant, an air outlet branch connected to the main air outlet pipe, and a dehumidification branch connected to the main dehumidification pipe. One end of the dehumidification chamber is connected to the air inlet branch, and the other ends are connected to the air outlet branch and the dehumidification branch, respectively. A filter is installed between the air inlet branch and the dehumidification chamber. The air inlet branch is equipped with an electrically controlled valve A, the air outlet branch is equipped with an electrically controlled valve B, and the dehumidification branch is equipped with an electrically controlled valve C.

[0014] The electric control valve of the present invention is controlled by a control system, and a normally closed electromagnetic valve commonly used in ventilation pipes can be selected as needed.

[0015] Furthermore, the circulating desiccant is a silica gel desiccant. A second heater for heating the silica gel desiccant is provided in the dehumidification chamber. The electric control valve A, electric control valve B, electric control valve C, and the second heater are controlled by the control system to perform the following actions:

[0016] (1) Select a dehumidification filter and dehumidification mechanism that has completed dehumidification, control the connected electric control valves A and B to be connected, and close the other electric control valves A, B, and C.

[0017] (2) After the preset first running time, close step (1) and select the opened electric control valve A and electric control valve B, and the filtering and dehumidification mechanism is marked as dehumidifying.

[0018] (3) Select another dehumidification filter and dehumidification mechanism that has completed dehumidification, control the electric control valve A and the electric control valve B connected to it to be connected, and close the other electric control valves A, B, and C.

[0019] (4) Turn on the second heater in the filter and dehumidification mechanism selected in step (1), and turn on the electrically controlled valve C connected to the filter and dehumidification mechanism selected in step (1).

[0020] (5) After the filter and dehumidification mechanism selected in step (1) is heated for a preset second time, the second heater and the electric control valve C are turned off, and the filter and dehumidification mechanism is marked as having completed dehumidification.

[0021] (6) Repeat steps (1) to (5) during the blowing phase, and perform steps (2), (4) and (5) during the non-blowing phase until all the filtering and dehumidifying mechanisms marked as dehumidifying have completed dehumidification.

[0022] Furthermore, the drying tank is provided with a drying plate, which is a porous far-infrared ceramic plate. The drying tank wall thickness is 3-5 cm, and the porous apertures on the drying tank wall have a diameter of 0.2-0.5 cm. The plate thickness is 1-5 cm, and the porous apertures on the plate have a diameter of 0.1-0.3 cm.

[0023] Furthermore, the porous far-infrared ceramic plate is prepared by the following method:

[0024] Step 1: By weight, 35-42 parts of kaolin, 30-50 parts of silica sol, 3-5 parts of nano-iron oxide, 1-3 parts of nano-magnesium oxide, and 20-30 parts of bamboo charcoal powder are mixed to form a glue solution.

[0025] Step 2: Select a porous polymer material plate with a suitable pore size, dip it into the glue obtained in step 1, and after the first layer of glue is dried, dip it into the glue obtained in step 1 again until the preset thickness and porous pore size are reached to obtain a prefabricated plate.

[0026] Step 3: The prefabricated plate is subjected to ceramic treatment at 780-850° C. in an inert gas or hydrogen environment to obtain a ceramic plate.

[0027] Step 4: After applying glaze on the outer layer of the ceramic plate, the plate is subjected to high-temperature treatment at 1100-1150° C. in an inert gas or hydrogen environment to obtain the porous far-infrared ceramic plate.

[0028] Furthermore, the drying chamber is equipped with an evaporator on the inner wall opposite the airtight door, and a drain pipe is provided at the bottom of the evaporator, which is connected to the liquid collection tank. A second blower is provided on the side of the airtight door facing the drying chamber and / or on the inner wall of the drying chamber. The second blower is connected to the control system signal and is activated under control. The drying chamber is equipped with an air flow return channel outside the drying tank.

[0029] The drying chamber is equipped with a slide rail, with a stopper at the end of the rail opposite the airtight door. The length of the slide rail matches the length of the drying tank. Several pulleys are installed on the sidewalls of the drying tank, matching the slide rails. The stopper presses against the wall of the drying tank's closed end to limit displacement.

[0030] Furthermore, when a second blower is provided on the airtight door, a sealing rubber ring is provided on the outer edge of the second blower. The sealing rubber ring matches the drying canister to form an airtight seal. A vent cavity is provided within the airtight door, covering the airflow return channel and the air inlet end of the second blower. The vent cavity is in air communication with the airflow return channel at the airflow return channel. A filter is provided at the connection point of the airtight door to the airflow return channel.

[0031] Furthermore, the vacuum device includes a vacuum pump and a vacuum pressure-maintaining tank. The vacuum pump's evacuation end is connected to the drying chamber and the vacuum pressure-maintaining tank, respectively. The vacuum pressure-maintaining tank is connected to the drying chamber. The pipeline connecting the vacuum pump and the drying chamber is equipped with an electrically controlled valve D, an electrically controlled valve E, and an electrically controlled valve F. The volume of the vacuum pressure-maintaining tank is K times that of the drying chamber, with K ranging from 1 / 10 to 1 / 2.

[0032] The control system includes the following steps when performing the voltage reduction control in step S2:

[0033] S2.1 controls the electronically controlled valves D and E to open, the electronically controlled valve F to close, and controls the vacuum pump to start.

[0034] S2.2 When the pressure in the drying chamber drops to 220-250 mmHg, control the electronically controlled valve F to open.

[0035] S2.3 When the pressure in the drying chamber drops to the target pressure, control the electric control valve E and the electric control valve F to close, and start the vacuum pump intermittently to maintain the pressure in the drying chamber.

[0036] Furthermore, before executing the pressure reduction control in step S2, the control system first controls the electronically controlled valves D and F to close, the electronically controlled valve E to open, and starts the vacuum pump to reduce the pressure in the vacuum pressure maintaining tank.

[0037] After the vacuum drying process is completed, the control system controls the electric control valves D and E to close and the electric control valve F to open, so that the pressure in the vacuum pressure maintaining tank returns to the room pressure.

[0038] The present invention also provides a freeze-drying method suitable for large-scale rapid freeze-drying, wherein a target object is freeze-dried using the aforementioned freeze-drying system suitable for large-scale rapid freeze-drying. The target object is first placed in a drying tank and frozen in a low-temperature freezer, and then the target object and the drying tank are transferred to a vacuum rapid drying system for drying.

[0039] The beneficial effects of the present invention are:

[0040] 1. The present invention optimizes the traditional freeze-drying method. Based on the specially constructed drying tank of the present invention, Chinese medicinal materials can be placed in a freezer for freezing, which significantly reduces the cost of freezing treatment.

[0041] 2. The present invention can achieve rapid drying, and the drying time is significantly shortened compared to existing freeze-drying technology.

[0042] 3. The present invention realizes batch and large-scale freeze-drying processing, which significantly improves the efficiency and processing cost of the freeze-drying process.

[0043] 4. Compared with the prior art, the freeze-drying process of the present invention can reduce the loss of the effective content of the treated material to varying degrees, and under certain conditions can even increase the effective content of the treated material. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the structure of the freeze-drying system of the present invention.

[0045] Figure 2 It is a structural schematic diagram of the low-temperature freezer of the present invention.

[0046] Figure 3 It is a structural schematic diagram of the dehumidification device of the present invention.

[0047] Figure 4 It is a structural schematic diagram of the drying device of the present invention.

[0048] Figure 5 It is a structural schematic diagram of the airtight door of the present invention.

[0049] Figure 6 It is a structural schematic diagram of the drying tank of the present invention.

[0050] Figure 7 This is a schematic structural diagram of the drying tank side wall and the drying material placement plate of the present invention.

[0051] Figure 8 Schematic diagram of the structure of the vacuum device of the present invention. DETAILED DESCRIPTION

[0052] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0053] Example 1

[0054] A freeze-drying system suitable for large-scale rapid freeze-drying, such as Figure 1 、 Figure 2 and Figure 4 As shown, it includes: a low-temperature freezer 1 and a vacuum rapid drying system, and the object to be dried is placed in a drying tank 5. The vacuum rapid drying system includes: a dehumidification device 2, a drying device 3, a vacuum device 4 and a control system, wherein a first blower (not shown in the figure) blows the outside air into the drying chamber 301 of the drying device 3 after dehumidification by the dehumidification device 1. The drying chamber 301 of the drying device 3 is connected to the vacuum device 4 and can be evacuated to a negative pressure state by the vacuum device 4. The drying tank 5 can be placed in the low-temperature freezer 1 and the drying chamber 301 of the drying device 3, and as shown Figure 6 As shown, the drying tank 5 is assembled from porous far-infrared ceramic plates with a main wavelength of 6-14 μm.

[0055] like Figure 4 As shown, the drying device 3 includes a drying chamber 301 for accommodating the drying canister 5. The drying chamber 301 is equipped with a heater (not shown) and a cooling system (not shown). One end of the drying chamber 301 is closed, and the other end is provided with an airtight door 302. A first ventilation duct 307 communicating with the dehumidification device 2 is provided at the top of the drying device 3, and a second ventilation duct 308 communicating with the vacuum device 4 is provided at the bottom.

[0056] The control system is connected to the first blower, vacuum device, heater, and cooling system signals, and performs the following control when vacuum rapid drying is required:

[0057] S1. Control the cooling system and heater to keep the ambient temperature in the drying chamber at the preset temperature.

[0058] S2. Start the vacuum device 4 to reduce the air pressure in the drying chamber 301 to 80 mmHg to 120 mmHg, and maintain the pressure for 1-5 minutes.

[0059] S3. Control the first blower to blow dry air into the drying chamber 301 so that the pressure in the drying chamber 301 is increased to 350 mmHg to 370 mmHg, and maintain the pressure for 1-5 minutes through the vacuum device.

[0060] S4. After repeating steps S2 and S3 for a preset number of times or a preset time, the pressure in the drying chamber 301 is restored to room pressure, completing the vacuum drying process.

[0061] The freeze-drying method using this system is as follows:

[0062] The target object is first placed in a drying can and frozen in a low-temperature freezer. The target object, along with the drying can, is then transferred to a vacuum rapid drying system for drying. For long-distance transfer, a refrigerated transport vehicle can be used. For short-distance transfer, a steel frame cart, overhead crane, forklift, or other tools can be used. It's best to maintain a low temperature throughout the transfer process, such as by covering the drying can 5 with insulation blanket or using a correspondingly designed insulation device with an insulation layer or cooling system installed outside the drying can 5 for transfer.

[0063] After the drying canister 5 loaded with the target object is transferred to the drying chamber 301 of the drying device 3, the control system executes steps S1 to S4 by controlling the first blower, vacuum device, heater, and cooling system until drying is complete. The first blower is activated to blow filtered, dried air into the drying chamber 301, completing the pressure increase in step S3 and the return to room pressure in step S4. The vacuum device is activated to remove moisture that may have been released into the drying chamber 301 by the target object, completing the pressure maintenance in the drying chamber 301 and the pressure reduction in step S2.

[0064] After the drying is completed, the drying canister 5 loaded with the target object is taken out of the drying chamber 301 , and the dried target object is removed and packaged to obtain a freeze-dried product.

[0065] The preset temperature in step S1, the pressure and time in step S2 and step S3 of the present invention have different optimal selections within the optional range for different Chinese medicinal materials or food raw materials.

[0066] The heater described herein can be an infrared heater or a heat pipe heater, depending on the needs. The cooling system described herein utilizes an existing compressor cooling system using Freon as a refrigerant, with the cooling system's evaporator assembly positioned within the drying chamber 301. The heater raises the temperature, while the cooling system lowers it. These two combined controls maintain the ambient temperature within the drying chamber 301 near the target temperature.

[0067] The present invention is compared with conventional liquid nitrogen freeze drying technology, owing to the need not to carry out liquid nitrogen freezing process, and can adopt existing conventional compressor cooling system to carry out cooling process, therefore can realize large-scale freeze drying process.According to the design of drying tank and corresponding drying device, the material amount of a drying device one-time drying process can be hundreds of kilograms to several tons, obviously more than the one-time processing capacity of conventional liquid nitrogen freeze drying system several kilograms to tens of kilograms.Therefore although the present invention has certain extension of freezing time (arrange as needed, general freezing process time is 12-48 hours), but drying process time is significantly shortened, combined with the great lifting of processing capacity, overall drying efficiency is significantly improved, processing cost is significantly reduced (without the need to use liquid nitrogen in large quantities).

[0068] In order to more clearly illustrate the advantages of the drying process of the present invention over the prior art, the following freeze-drying treatment was performed on fresh Gastrodia tubers of the same batch as the target based on the method of Example 1 and the method of Comparative Example 1, wherein:

[0069] The temperature environment in the low-temperature freezer 1 is -20°C, and the freezing time of the freshly washed Gastrodia elata in the low-temperature freezer 1 is 2 hours.

[0070] The specific process parameters of step S2 of Example 1 are as follows: the air pressure in the drying chamber 301 is reduced to 87 mmHg and maintained at this pressure for 3 minutes.

[0071] The specific process parameters of step S3 of Example 1 are as follows: the air pressure in the drying chamber 301 is increased to 362 mmHg, and the pressure is maintained for 2 minutes by a vacuum device.

[0072] The preset time in step S4 is 2 hours, and the preset temperature in step S1 is controlled as follows:

[0073] When drying begins, the ambient temperature in the drying chamber 301 is -20°C.

[0074] After drying for 5 minutes, the temperature was raised to -10°C within 3 minutes and maintained for 12 minutes.

[0075] The temperature was raised to 0°C within 2 minutes and maintained for 18 minutes.

[0076] The temperature was raised to 20°C within 3 minutes and maintained for 5 minutes.

[0077] The temperature was raised to 30°C within 3 minutes and maintained until drying was complete.

[0078] Comparative Example 1

[0079] Freezing stage:

[0080] Place the cleaned fresh Gastrodia elata directly on the freezer shelf of the freezer to pre-freeze to about -20°C (freezer temperature is -20°C, about 2 hours). During this period, use liquid nitrogen to reduce the ambient temperature in the freeze-drying chamber to about -60°C.

[0081] The pre-frozen dried product was placed in the processing chamber of the freeze-drying device, vacuumed to 100 mmHg, and maintained at this vacuum and temperature for 3 hours.

[0082] Drying stage:

[0083] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to -40°C for 3 hours.

[0084] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to -20°C for 3 hours.

[0085] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to -10°C for 3 hours.

[0086] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to -5°C for 3 hours.

[0087] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to 0°C for 3 hours.

[0088] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to 5°C for 2 hours.

[0089] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to 10°C for 2 hours.

[0090] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to 15°C for 2 hours.

[0091] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to 25°C for 2 hours.

[0092] Maintain the vacuum level unchanged and raise the temperature in the freeze-drying chamber to 35°C for 2 hours.

[0093] It can be seen that the drying method adopted in the present invention is significantly different from the prior art, specifically:

[0094] 1. In the freezing stage, the present invention only requires freezing treatment in a conventional low-temperature freezer, that is, a conventional cold chain can meet the freezing needs without the need for additional liquid nitrogen for further cooling.

[0095] 2. Drying stage: The vacuum degree in the drying stage of the present invention is changed regularly, and there are special restrictions on the pressure value and maintenance time of each stage.

[0096] In order to characterize the freeze-drying effects of the freeze-dried Gastrodia elata of Example 1 and the freeze-dried Gastrodia elata of Comparative Example 1, the present invention uses the content of gastrodin (i.e., gastrodin) in the freeze-dried Gastrodia elata and the moisture content of the freeze-dried Gastrodia elata as characterizations.

[0097] The content of gastrodin was tested according to the method published by Zhang Hui, Sha Dongxu and others in "HPLC method for determination of gastrodin content in Gastrodia elata and its preparations", Journal of Shenyang Medical University, Volume 17 Supplement, June 2000.

[0098] The moisture content is tested using a coulometric moisture meter.

[0099] The test results are shown in Table 1:

[0100] Table 1. Gastrodin content and moisture content of freeze-dried Gastrodia elata

[0101] project Gastrodin content (mg / g) Moisture content (%) Example 1 9.73 3 Comparative Example 1 8.25 3

[0102] It can be seen from the above table:

[0103] 1. Using the freeze-drying method of the present invention, the drying treatment time is 1 hour to reach the moisture content that the prior art needs 25 hours of drying treatment to achieve, and the drying efficiency is significantly improved. The main reason is that, in conventional constant vacuum drying, the air pressure difference inside and outside the Gastrodia elata tissue will quickly shrink to a relative balance, and the drying process mainly depends on the natural volatilization of water vapor. In the dynamic pressure-changing process of the present invention, the continuous change of the ambient pressure will cause the continuous change of the pressure in the Gastrodia elata tissue, so that the water vapor inside the Gastrodia elata is accelerated to overflow by the constantly changing pressure effect, thereby accelerating the drying efficiency.

[0104] 2. Using the freeze-drying method of the present invention, the gastrodin content is increased by about 17.93% compared with Comparative Example 1. After research, the applicant believes that the reason for this characteristic may be:

[0105] (1) During the freezing and drying process of the present invention, Gastrodia elata is exposed to a far-infrared energy environment with a main wavelength of 6-14 μm.

[0106] (2) The dynamic pressure-variable drying process of the present invention forms better micropores inside the Gastrodia elata, which, on the one hand, facilitates the overflow of water molecules, thereby accelerating drying and reducing the loss of gastrodin. On the other hand, it can accelerate the release rate of gastrodin in the solvent environment, thereby increasing the detected content.

[0107] 3. The present invention can use a -20°C freezer to freeze the Gastrodia elata, rather than the -60°C freezer used in conventional freeze-drying technology. The reason for this is that conventional freeze-drying technology uses -60°C in order, on the one hand, to maintain the content of active and effective substances in the Gastrodia elata and a longer temperature rise interval through rapid freezing, and on the other hand, to prevent the Gastrodia elata from decomposing and spoiling by means of ultra-low temperatures. However, the present invention freezes the Gastrodia elata by placing it in a drying tank 5 with an infrared energy field of a specific wavelength. This can achieve the freezing effect that conventional technology requires ultra-low temperature treatment to achieve through the infrared energy field of a specific wavelength. Therefore, even if the Gastrodia elata is frozen in a conventional freezer, the content of active and effective substances such as gastrodin in the obtained Gastrodia elata is not reduced, but rather increases.

[0108] In order to further verify the effect of far-infrared energy on the freeze-dried product of the present invention, the applicant conducted comparative experiments 2 to 5, specifically:

[0109] Comparative Example 2

[0110] The remaining structures and steps are the same as those in Example 1, except that the drying tank 5 is assembled from porous near-infrared ceramic plates with a wavelength of 1-4 μm.

[0111] Comparative Example 3

[0112] The remaining structures and steps are the same as those in Example 1, except that the drying tank 5 is assembled from porous far-infrared ceramic plates with a wavelength of 20-40 μm.

[0113] Comparative Example 4

[0114] The remaining structures and steps are the same as those in Example 1, except that the drying tank 5 is assembled from porous far-infrared ceramic plates with a wavelength of 150-200 μm.

[0115] Comparative Example 5

[0116] The remaining structures and steps are the same as those in Example 1, except that the drying tank 5 is assembled from conventional porous ceramic plates.

[0117] The gastrodin content and moisture content of the freeze-dried product were tested, and the results are shown in Table 2:

[0118] Table 2. Gastrodin content and moisture content of freeze-dried Gastrodia elata under different infrared wavelength environments

[0119] project Gastrodin content (mg / g) Moisture content (%) Example 1 9.73 3 Comparative Example 2 9.12 3 Comparative Example 3 9.08 3 Comparative Example 4 8.63 3 Comparative Example 5 8.51 3 Comparative Example 1 8.25 3

[0120] From the above table, we can see that the change of infrared wavelength has no effect on the moisture content, but has a relatively obvious effect on the content of gastrodin, among which:

[0121] From the comparison between Comparative Example 5 and Comparative Example 1, it can be seen that the drying treatment speed does have an impact on the content of gastrodin in the freeze-dried Gastrodia elata, and the faster the drying rate, the higher the gastrodin content in the freeze-dried Gastrodia elata.

[0122] From the comparison between Comparative Example 5 and Comparative Examples 2-4 and Example 1, it can be seen that the imparting of infrared energy field can increase the content of gastrodin in freeze-dried Gastrodia elata.

[0123] From the comparison between Comparative Examples 2-4 and Example 1, it can be seen that the gastrodin content of the freeze-dried Gastrodia elata obtained in the infrared energy field environment of 6-14 μm is the highest.

[0124] The choice of visible infrared energy environment has a significant impact on the content of effective substances in freeze-dried products.

[0125] After research, the applicant believes that the possible reasons for the above test results are:

[0126] (1) Fresh Gastrodia elata still has good biological activity when kept fresh in a low-temperature environment, and gradually decreases as the preservation time is extended, especially during the drying process, when the ambient temperature is raised to room temperature or above, the rate of loss of activity of Gastrodia elata is relatively fast. According to existing research (such as research reports by Hiroko Ishii, Eita Matsubara, and others), infrared rays of 6-14 μm have a promoting effect on plant growth. Therefore, during the freeze-drying process of the present invention, the special infrared energy field provided by the drying tank 5 can, on the one hand, slow down the rate of loss of biological activity of Gastrodia elata by energy imparting, and on the other hand, inhibit bacterial growth. Thus, the freezing effect of ultra-low temperature freezing of Gastrodia elata can be achieved by freezing Gastrodia elata in a conventional freezer. At the same time, since the special infrared energy field continuously covers Gastrodia elata during the entire process of the present invention, the rate of loss of active ingredients in Gastrodia elata is significantly lower than that of conventional freeze-drying technology, especially in the temperature rising and drying stage. This is also the main reason why the Gastrodia elata obtained by freeze-drying the present invention has a higher content of active effective substances than the Gastrodia elata obtained by conventional freeze-drying technology.

[0127] (2) The infrared energy field will have an oscillating effect at a specific frequency on the water in the Gastrodia elata. On the one hand, it will disperse the large water molecule clusters into small molecule clusters, thereby increasing the molecular distance between the formed solid water and reducing the intermolecular force, which is beneficial to improving the sublimation of solid water. On the other hand, it will promote the inward transfer of energy during the heating process and accelerate the heating process. The above two aspects are beneficial to reducing the time required for the drying process. Combined with the effect of the micropores generated by dynamic pressure transformation to promote the overflow of water molecules, the drying process time can reach about 2 hours of Example 1 of the present invention, thereby reducing the loss of gastrodin during the drying process.

[0128] (3) The specific oscillation frequency of the infrared energy field may cause a change in the polarity of water molecules, thereby affecting the interaction force between gastrodin and water molecules, reducing the amount of gastrodin lost as the water molecules evaporate during the drying process, thereby reducing the loss of gastrodin during the drying process.

[0129] Example 2

[0130] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 1, Figure 3 As shown, the dehumidification device: 2 includes: an air inlet main pipe 201 connected to the outside, an air outlet main pipe 207 connected to the drying chamber, a dehumidification main pipe 209 connected to the outside, two groups or three groups or four groups or other design required numbers of filtering and dehumidification mechanisms arranged between the air inlet main pipe 201 and the air outlet main pipe 207 and connected to the air inlet main pipe 201, the air outlet main pipe 207, and the dehumidification main pipe 209 respectively.

[0131] The dehumidification mechanism includes: an air inlet branch pipe 202 connected to the air inlet main pipe 201, a dehumidification chamber filled with a circulating desiccant 205, an air outlet branch pipe 206 connected to the air outlet main pipe 207, and a dehumidification branch pipe 211 connected to the dehumidification main pipe 209. One end of the dehumidification chamber is connected to the air inlet branch pipe 202, and the other end is connected to the air outlet branch pipe 206 and the dehumidification branch pipe 211 respectively. A filter 204 is installed between the air inlet branch pipe 202 and the dehumidification chamber. The air inlet branch pipe 202 is provided with an electric control valve A, Figure 3 The mark 203 in the middle is that the gas outlet pipe is provided with an electric control valve B. Figure 3 The dehumidification branch pipe 211 is provided with an electric control valve C, which is marked as 208. Figure 3 Marked as 210.

[0132] The circulating desiccant 205 is a silica gel desiccant. A second heater 212 is provided in the dehumidification chamber to heat the silica gel desiccant. The electric control valves A, B, C, and the second heater 212 are controlled by the control system to perform the following actions:

[0133] (1) Select a dehumidification filter and dehumidification mechanism that has completed dehumidification, control the connected electric control valves A and B to be connected, and close the other electric control valves A, B, and C.

[0134] (2) After the preset first running time, close step (1) and select the opened electric control valve A and electric control valve B, and the filtering and dehumidification mechanism is marked as dehumidifying.

[0135] (3) Select another dehumidification filter and dehumidification mechanism that has completed dehumidification, control the electric control valve A and the electric control valve B connected to it to be connected, and close the other electric control valves A, B, and C.

[0136] (4) Turn on the second heater in the filter and dehumidification mechanism selected in step (1), and turn on the electrically controlled valve C connected to the filter and dehumidification mechanism selected in step (1).

[0137] (5) After the filter and dehumidification mechanism selected in step (1) is heated for a preset second time, the second heater and the electric control valve C are turned off, and the filter and dehumidification mechanism is marked as having completed dehumidification.

[0138] (6) Repeat steps (1) to (5) during the blowing phase, and perform steps (2), (4) and (5) during the non-blowing phase until all the filtering and dehumidifying mechanisms marked as dehumidifying have completed dehumidification.

[0139] Existing dehumidification devices that dry the incoming air generally use a processing mechanism with a desiccant to dehumidify the incoming air. However, the existing dehumidification processing device can only stop dehumidifying the incoming air after the desiccant fails, and the incoming air can only be dehumidified again after the desiccant is replaced. This seriously limits the working efficiency of the drying device that requires dry air for pressure control. Even during the low-pressure drying process of the drying device, the drying process cannot be easily stopped, otherwise it is likely to cause the dried product to be unqualified. At this time, if the desiccant fails, the moisture content of the air rushing into the drying device will be too high, affecting the moisture content of the final dried product. The existing method for solving the above problem is generally: before drying the product, first replace the desiccant in the dehumidification device with a new desiccant, and ensure that the amount of desiccant added at least meets the amount required for one drying process, as well as the necessary margin. This leads to a huge amount of desiccant used and high costs.

[0140] After adopting the dehumidification device of Example 2, through the synergistic effect of multiple groups of filtering and dehumidification mechanisms, when the desiccant in one group of filtering and dehumidification mechanisms tends to be saturated with water, another group of filtering and dehumidification mechanisms can be switched, thereby ensuring continuous and effective dehumidification of the air supply. In addition, after the desiccant in the filtering and dehumidification mechanism is saturated with water, the present invention also provides a heating and dehydration function, so that the silica gel desiccant can be transformed from a desiccant that has lost water absorption after losing water due to heat to a desiccant that has lost water, so that it can be on standby for dehumidification again. Therefore, the dehumidification device of the present invention not only ensures continuous and effective drying of the air supply, but also significantly reduces the amount of desiccant used, allowing the desiccant to be recycled and reused during operation, thereby improving work efficiency.

[0141] Example 3

[0142] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 1, Figure 6 and Figure 7 As shown, the drying jar 5 is provided with a dried product placement plate 502, which is a porous far-infrared ceramic plate. The drying jar wall 501 has a thickness of 3-5 cm, preferably 4 cm. The porous apertures in the drying jar wall 501 have a diameter of 0.2-0.5 cm, preferably 0.3 cm. The placement plate 502 has a thickness of 1-5 cm, preferably 3 cm, and a porous aperture of 0.1-0.3 cm, preferably 0.2 cm.

[0143] The above-described structural arrangement allows the drying tank 5 to have good air permeability, thereby facilitating more comprehensive coverage of the object to be dried by the infrared energy field of the present invention. Furthermore, the evaporated water can be quickly carried away from the object to be dried by the flowing air flow during the dynamic pressure change process, allowing the moisture within the object to be more easily dissipated, thereby reducing drying time.

[0144] Example 4

[0145] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 3, the porous far-infrared ceramic plate is prepared by the following method:

[0146] Step 1: By mass, 35-42 parts of kaolin, 30-50 parts of silica sol, 3-5 parts of nano iron oxide, 1-3 parts of nano magnesium oxide, and 20-30 parts of bamboo charcoal powder are mixed to form a glue solution. Preferably, 40 parts of kaolin, 40 parts of silica sol, 4 parts of nano iron oxide, 2 parts of nano magnesium oxide, and 25 parts of bamboo charcoal powder are mixed to form a glue solution.

[0147] Step 2: Select a porous polymer material plate with a suitable pore size, dip it into the glue obtained in step 1, and after the first layer of glue is dried, dip it into the glue obtained in step 1 again until the preset thickness and porous pore size are reached to obtain a prefabricated plate.

[0148] Step 3: The prefabricated plate is ceramicized in an inert gas or hydrogen environment at 780-850° C., preferably 800° C., to obtain a ceramic plate.

[0149] Step 4: After applying glaze on the outer layer of the ceramic plate, high-temperature treatment is performed at 1100-1150° C., preferably 1200° C., in an inert gas or hydrogen environment to obtain the porous far-infrared ceramic plate.

[0150] The research in Example 1 demonstrated that infrared energy in the 6-14 μm range is beneficial for increasing the active ingredient content of freeze-dried products. Therefore, the applicants conducted research and developed a method for preparing the porous far-infrared ceramic plate described in Example 4. The porous far-infrared ceramic plate produced using this method exhibited infrared wavelength detection, indicating that wavelengths in the 6-14 μm range accounted for over 97%.

[0151] Comparative Example 5

[0152] The remaining steps are the same as those in Example 4, except that nano-iron oxide is not added to the glue in step 1.

[0153] Comparative Example 6

[0154] The remaining steps are the same as those in Example 4, except that nano-magnesium oxide is not added to the glue in step 1.

[0155] Comparative Example 7

[0156] The remaining steps are the same as those in Example 4, except that nano-iron oxide and nano-magnesium oxide are not added to the glue solution in step 1.

[0157] Comparative Example 8

[0158] The remaining steps are the same as those in Example 4, except that in step 1, the bamboo charcoal powder is replaced with nano carbon black of equal mass in the glue solution.

[0159] Infrared wavelength detection was performed on Example 4 and Comparative Examples 5-8, and the results are shown in Table 3.

[0160] Table 3. Infrared wavelength detection results of various porous ceramic plates

[0161] Wavelength range (μm) 6-14μm wavelength ratio Example 4 6-15 97％ Comparative Example 5 3-100 18％ Comparative Example 6 3-108 15％ Comparative Example 7 2-110 9％ Comparative Example 8 102-832 0％

[0162] Comparison of Comparative Example 8 with Example 4 and Comparative Examples 5-7 shows that the addition of bamboo charcoal powder can help the infrared wavelength emitted by the prepared porous ceramic plate tend to the target wavelength range. Even when carbon black powder is used instead, the results are significantly different.

[0163] A comparison of Example 4 and Comparative Examples 5-7 shows that the simultaneous addition of nano-iron oxide and nano-magnesium oxide produces a synergistic effect with bamboo charcoal powder, concentrating the infrared wavelengths emitted by the resulting porous ceramic plate within the target range of 6-14 μm. The results obtained when only nano-iron oxide or nano-magnesium oxide is added are not significantly different from those obtained when nano-iron oxide or nano-magnesium oxide is omitted. Using nano-iron oxide or nano-magnesium oxide alone does not effectively optimize and control the infrared wavelengths emitted by the porous ceramic plate.

[0164] Example 5

[0165] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 1, Figure 3 As shown, the drying chamber 301 is provided with an evaporator 6 on the inner wall opposite the airtight door 302. A drain pipe 309 is provided at the bottom end of the evaporator 6. The drain pipe 309 is connected to the liquid collection tank 7. A second blower 303 is provided on the side of the airtight door 302 facing the drying chamber 301 and / or on the inner wall of the drying chamber 301. The drying chamber 303 is provided with an airflow return channel outside the drying tank 5.

[0166] The addition of a second blower 303 keeps the airflow in the drying chamber 301 flowing. This allows evaporated water vapor to quickly separate from the target object, facilitating its evaporation and accelerating the drying process. Furthermore, the airflow in the drying chamber 301 continuously flows through the evaporator 6. As a result, when drying at room temperature, the moisture in the airflow passing through the evaporator 6 is quickly condensed and accumulated on the evaporator 6, falling into the drain pipe 309 for further recovery into the liquid collection tank 7. This allows the atmosphere in the drying chamber 301 to remain low-humidity even when drying above room temperature. This helps accelerate the drying process. For freeze-dried Gastrodia elata, employing the technical solution of Example 5, the time required to freeze-dry to a moisture content of 3% can be reduced from 2 hours in Example 1 to 100 minutes.

[0167] At the same time, on the one hand, it reduces the corrosion effect of water vapor entering the vacuum pump on the vacuum pump, thereby increasing the service life of the equipment. On the other hand, the recovered water may also contain a certain amount of active and effective substances, which can be recycled and reused.

[0168] Example 6

[0169] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 5, Figure 4 As shown, a slide rail 305 is provided within the drying chamber 301, and a stopper 310 is provided at the end of the slide rail opposite the airtight door 302. The length of the slide rail 305 matches the length of the drying canister 5. Several pulleys 501 are provided on the sidewalls of the drying canister 5. These pulleys 501 are mounted on the sidewalls of the drying canister 5 via mounting brackets 502, matching the slide rail 305. The stopper 310 also presses against the wall of the closed end of the drying canister 5 to limit displacement.

[0170] This arrangement facilitates the sliding operation of the drying tank 5 in and out of the drying chamber 301, which can reduce the time required for the drying tank 5 to be moved in and out. This is especially true when large-scale drying is performed, as the drying tank 5 contains many objects and has a large weight. This design can reduce the difficulty of operation.

[0171] Example 7

[0172] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 6, Figure 4 and 5 As shown, when the airtight door 302 is equipped with a second blower 303, a sealing rubber ring 304 is provided on the outer edge of the second blower 303 on the airtight door 302. The sealing rubber ring 304 matches the drying canister 5 to form an airtight seal. The airtight door 302 is provided with a vent cavity 3022 covering the airflow return channel and the air inlet end of the second blower 303. The vent cavity 3022 is in air communication with the airflow return channel at the airflow return channel. The airtight door 302 is provided with a filter 3021 at the connection point of the airflow return channel.

[0173] This arrangement ensures that the airflow driven by the second blower 303 primarily flows through the drying can 5, passes through the target material, and then exits through the openings in the drying can 5 wall, effectively removing moisture from the target material and significantly improving the stability of the freeze-dried product's moisture content. The filter prevents low-mass particles, which may be generated during the freeze-drying process, from being drawn into the ventilation chamber 3022 by the airflow, particularly during backpressure or depressurization, potentially damaging the second blower 303.

[0174] Example 8

[0175] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 6, Figure 8As shown, the vacuum device includes: a vacuum pump 8 and a vacuum pressure tank 9. The vacuum end of the vacuum pump 8 is connected to the drying chamber 301 and the vacuum pressure tank 9 respectively, and the vacuum pressure tank 9 is connected to the drying chamber 301. The vacuum pump 8 is connected to the drying chamber 301 through a second ventilation pipe 308, and the second ventilation pipe 308 is provided with an electric control valve D. Figure 8 The vacuum pump 8 is connected to the vacuum pressure tank 9 via a third ventilation pipe 13, and an electric control valve E is provided on the third ventilation pipe 13. Figure 8 The vacuum pressure-maintaining tank 9 is connected to the drying chamber 301 via a fourth ventilation pipe 14, and an electric control valve F is provided on the fourth ventilation pipe 14. Figure 8 The middle mark is 11. The volume of the vacuum pressure-maintaining tank 9 is K times that of the drying chamber 301, and the value range of K is 1 / 10 to 1 / 2.

[0176] The control system includes the following steps when performing the voltage reduction control in step S2:

[0177] S2.1 controls the electronically controlled valves D and E to open, the electronically controlled valve F to close, and controls the vacuum pump to start.

[0178] S2.2 When the pressure in the drying chamber drops to 40-50 mmHg, control the electronically controlled valve F to open.

[0179] S2.3 When the pressure in the drying chamber drops to the target pressure, the electrically controlled valves E and F are controlled to close, and the vacuum pump is started intermittently to maintain the pressure in the drying chamber 301.

[0180] The present invention incorporates a pressure drop operation through the vacuum pressure-maintaining tank 9 during the continuous vacuuming process. The implementation principle is as follows: the volume of the vacuum pressure-maintaining tank 9 is lower than that of the drying chamber 301. When both are continuously vacuumed by the vacuum pump 8 at the beginning, the pressure in the vacuum pressure-maintaining tank 9 drops faster than that in the drying chamber 301. Therefore, it can have a lower vacuum degree than the drying chamber 301 at the same time. When the vacuum pressure-maintaining tank 9 and the drying chamber 301 are connected during the vacuuming process, the pressure between the vacuum pressure-maintaining tank 9 and the drying chamber 301 will be instantly balanced, causing a sudden drop in the vacuum degree in the drying chamber 301. Afterwards, the vacuum pump 8 continues to extract the atmosphere in the drying chamber 301, so that the vacuum degree in the drying chamber 301 steadily drops to the target pressure.

[0181] Compared to conventional continuous vacuuming, the present invention uses a sudden pressure drop during vacuuming, causing water vapor inside the target object to escape rapidly due to a momentary high pressure differential. This not only accelerates the escape rate of water vapor, but also encourages the formation of more unobstructed micropores within the target object. This not only speeds up the drying process, but also facilitates the release of effective substances.

[0182] Taking Gastrodia elata as an example, the applicant used the freeze-drying system of the technical solution of Example 8 to freeze-dry Gastrodia elata, which can reduce the moisture content of fresh Gastrodia elata to 3% within 1 hour, and the freeze-drying efficiency is significantly improved.

[0183] Example 9

[0184] Based on the freeze-drying system suitable for large-scale rapid freeze-drying in Example 8, before executing the pressure reduction control of step S2, the control system first controls the electric control valves D and F to close, the electric control valve E to open, and starts the vacuum pump 8 to reduce the pressure in the vacuum pressure maintaining tank 9.

[0185] After the vacuum drying process is completed, the control system controls the electric control valves D and E to close and the electric control valve F to open, so that the pressure in the vacuum pressure tank 9 returns to the room pressure.

[0186] This operation allows the vacuum pressure tank 9 to maintain a relatively low pressure during operation, thereby facilitating rapid pressure balancing within the drying chamber 301 and minimizing the magnitude of the pressure drop within the drying chamber 301, thereby improving drying efficiency. When the vacuum pressure tank 9 is not in operation, it can be restored to room pressure, thus protecting the vacuum pressure tank 9.

[0187] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A freeze-drying system suitable for large-scale rapid freeze-drying, characterized in that: include: Low temperature freezer and vacuum rapid drying system, the objects to be dried are placed in the drying tank; The vacuum rapid drying system comprises: a dehumidifying device, a drying device, a vacuum device, and a control system, wherein a first blower blows the outside air dehumidified by the dehumidifying device into a drying chamber of the drying device; the drying chamber of the drying device is connected to the vacuum device and can be evacuated to a negative pressure state by the vacuum device; the drying tank can be placed in a low-temperature freezer and the drying chamber of the drying device, and the drying tank is assembled from porous far-infrared ceramic plates with a wavelength of 6-14 μm; The drying device comprises: a drying chamber for placing a drying can, wherein a heater and a cooling system are provided in the drying chamber, and one end of the drying chamber is closed and the other end is provided with an airtight door; The control system is connected to the first blower, vacuum device, heater, and cooling system signals, and performs the following control when vacuum rapid drying is required: S1. Control the cooling system and heater to maintain the ambient temperature in the drying chamber at a preset temperature. S2. Start the vacuum device, reduce the pressure in the drying chamber to 80mmHg to 120mmHg, and maintain the pressure for 1-5 minutes; S3 controls the first blower to blow dry air into the drying chamber, so that the pressure in the drying chamber is raised to 350mmHg to 370mmHg, and the pressure is maintained by the vacuum device for 1-5 minutes; S4 repeats steps S2 and S3 to a preset number of times or a preset time, the drying chamber returns to room pressure, completing the vacuum drying process; The drying chamber is provided with an evaporator on the inner cavity wall opposite the airtight door, and a drain pipe is provided at the bottom of the evaporator, which is connected to the liquid collecting tank; a second blower is provided on the side of the airtight door facing the drying chamber, and the second blower is connected to the control system signal and is controlled to start; the drying chamber is provided with an air flow return channel outside the drying tank; A slide rail is provided in the drying chamber, and a stopper is provided at the end of the slide rail opposite the airtight door. The length of the slide rail matches the length of the drying tank. Several pulleys are provided on the side wall of the drying tank, which match the slide rails. The tank wall at the closed end of the drying tank is pressed by the stopper to limit displacement. A sealing rubber ring is provided on the outer edge of the second blower on the airtight door; the sealing rubber ring matches the drying tank to form an airtight seal; a ventilation cavity covering the airflow return channel and the air inlet end of the second blower is provided inside the airtight door, and the ventilation cavity is in air communication with the airflow return channel at the airflow return channel; the airtight door is provided with a filter at the connection of the airflow return channel.

2. The freeze-drying system suitable for large-scale rapid freeze-drying according to claim 1, characterized in that: The dehumidification device includes an air inlet main pipe connected to the outside, an air outlet main pipe connected to the drying chamber, a moisture removal main pipe connected to the outside, and at least two groups of filtering and moisture removal mechanisms arranged between the air inlet main pipe and the air outlet main pipe and connected to the air inlet main pipe, the air outlet main pipe, and the moisture removal main pipe respectively; The filtering and dehumidification mechanism includes: an air inlet branch pipe connected to the air inlet main pipe, a dehumidification chamber filled with a circulating desiccant, an air outlet branch pipe connected to the air outlet main pipe, and a dehumidification branch pipe connected to the dehumidification main pipe; one end of the dehumidification chamber is connected to the air inlet branch pipe, and the other end is connected to the air outlet branch pipe and the dehumidification branch pipe respectively, and a filter is provided between the air inlet branch pipe and the dehumidification chamber; an electric control valve A is provided on the air inlet branch pipe, an electric control valve B is provided on the air outlet branch pipe, and an electric control valve C is provided on the dehumidification branch pipe.

3. The freeze-drying system suitable for large-scale rapid freeze-drying according to claim 2, characterized in that: The circulating desiccant is a silica gel desiccant; a second heater for heating the silica gel desiccant is provided in the dehumidification chamber; the electric control valves A, B, C, and the second heater are controlled by the control system to perform the following actions: (1) Select a dehumidification filter and dehumidification mechanism that has completed dehumidification, control the connected electric control valve A and electric control valve B to be connected, and close the other electric control valves A, B, and C; (2) After the preset first running time, close the electric control valve A and the electric control valve B that are opened in step (1), and the filtration and dehumidification mechanism is marked as dehumidification; (3) Select another dehumidification filter and dehumidification mechanism that has completed dehumidification, control the electric control valve A and electric control valve B connected to it to be connected, and close the other electric control valves A, B, and C; (4) turning on the second heater in the filter and dehumidification mechanism selected in step (1), and turning on the electrically controlled valve C connected to the filter and dehumidification mechanism selected in step (1); (5) After the filter and dehumidification mechanism selected in step (1) is heated for a preset second time, the second heater and the electric control valve C are closed, and the filter and dehumidification mechanism is marked as dehumidification completed; (6) Repeat steps (1) to (5) during the blowing phase, and perform steps (2), (4) and (5) during the non-blowing phase until all the filter and dehumidification mechanisms marked as dehumidifying have completed dehumidification.

4. The freeze-drying system suitable for large-scale rapid freeze-drying according to claim 1, characterized in that: The drying tank is provided with a dried object placement plate, which is a porous far-infrared ceramic plate; the drying tank wall thickness is 3-5 cm, and the porous apertures on the drying tank wall are 0.2-0.5 cm; the dried object placement plate thickness is 1-5 cm, and the porous apertures on the dried object placement plate are 0.1-0.3 cm.

5. The freeze-drying system suitable for large-scale rapid freeze-drying according to any one of claims 1 or 4, characterized in that: The porous far-infrared ceramic plate is prepared by the following method: Step 1: By weight, 35-42 parts of kaolin, 30-50 parts of silica sol, 3-5 parts of nano-iron oxide, 1-3 parts of nano-magnesium oxide, and 20-30 parts of bamboo charcoal powder are mixed to form a glue solution; Step 2: Select a porous polymer material plate with a suitable pore size, dip it into the glue obtained in step 1, and after the first layer of glue is dried, dip it into the glue obtained in step 1 again until the preset thickness and pore size are reached to obtain a prefabricated plate; Step 3: ceramicizing the prefabricated plate at 780-850° C. in an inert gas or hydrogen environment to obtain a ceramic plate; Step 4: After applying glaze on the outer layer of the ceramic plate, the plate is subjected to high-temperature treatment at 1100-1150° C. in an inert gas or hydrogen environment to obtain the porous far-infrared ceramic plate.

6. The freeze-drying system suitable for large-scale rapid freeze-drying according to claim 1, characterized in that: The vacuum device includes: a vacuum pump and a vacuum pressure-maintaining tank; the vacuum pump's evacuation end is connected to the drying chamber and the vacuum pressure-maintaining tank, respectively, and the vacuum pressure-maintaining tank is connected to the drying chamber; an electrically controlled valve D is provided on the pipeline connecting the vacuum pump and the drying chamber, an electrically controlled valve E is provided on the pipeline connecting the vacuum pump and the vacuum pressure-maintaining tank, and an electrically controlled valve F is provided on the pipeline connecting the vacuum pump and the vacuum pressure-maintaining tank. The volume of the vacuum pressure-maintaining tank is K times that of the drying chamber, with the value of K ranging from 1 / 10 to 1 / 2. The control system includes the following steps when performing the voltage reduction control in step S2: S2.1 Controls the electronically controlled valves D and E to open, the electronically controlled valve F to close, and controls the vacuum pump to start; S2.2 When the pressure in the drying chamber drops to 220-250 mmHg, the electric control valve F is controlled to open; S2.3 When the pressure in the drying chamber drops to the target pressure, control the electric control valve E and the electric control valve F to close, and start the vacuum pump intermittently to maintain the pressure in the drying chamber.

7. The freeze-drying system suitable for large-scale rapid freeze-drying according to claim 6, characterized in that: Before executing the pressure reduction control in step S2, the control system first controls the electric control valves D and F to close, the electric control valve E to open, and starts the vacuum pump to reduce the pressure in the vacuum pressure tank; After the vacuum drying process is completed, the control system controls the electric control valves D and E to close and the electric control valve F to open, so that the pressure in the vacuum pressure maintaining tank returns to the room pressure.

8. A freeze-drying method suitable for large-scale rapid freeze-drying, characterized in that: Freeze-drying the target substance using the freeze-drying system suitable for large-scale rapid freeze-drying as described in any one of claims 1 to 7; The target object is first placed in a drying tank and frozen in a low-temperature freezer, and then the target object and the drying tank are transferred to a vacuum rapid drying system for drying.

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