Fruit and vegetable instant pressure differential flash drying apparatus

Abstract

The utility model discloses a kind of fruit and vegetable instantaneous pressure difference flash evaporation drying equipment, and drying equipment includes: multiple material drying bins, every material drying bin includes bin body, driving part, the bin door is slidably sealed in one end of the bin body, temperature monitor, moisture detector, pressure gauge, exhaust port, drain port are equipped on the bin body, the driving part drives the bin door sliding to open and close bin body;Vacuum system, it includes vacuum unit, vacuum bin, the vacuum bin with the vacuum end of the vacuum unit is communicated;Steam generator, its steam outlet end is communicated with every bin body inside;High-pressure dry hot air heating system, its dry hot air outlet end is communicated with every bin body inside;Control system.The utility model has beneficial effect, realizes the double promotion of drying efficiency and drying quality, effectively solve the bottleneck problem of long drying time and large nutrient loss in fruit and vegetable crisp piece drying, and application prospect is wide.

Description

Technical Field

[0001] This utility model relates to the field of fruit and vegetable drying technology. More specifically, this utility model relates to a flash drying device for fruits and vegetables under instantaneous pressure difference. Background Technology

[0002] Beginning in the 1990s, with the increasing demand for delicious snacks, fruit and vegetable drying and puffing technology gradually became a research and industrialization hotspot in the food processing field. Traditional fruit and vegetable drying and puffing technologies mainly include room temperature frying and puffing, low-temperature vacuum oil bath, vacuum microwave puffing, or vacuum drying, but these methods generally suffer from high energy consumption, low efficiency, and poor product quality. In particular, room temperature frying and puffing foods easily generate harmful substances such as acrylamide, leading most consumers to avoid excessive consumption, and these methods have gradually been phased out. Although vacuum dehydration dryers avoid the problems of frying, the dehydration process is time-consuming, and oil-soluble nutrients in fruits and vegetables continuously permeate and are lost, with a retention rate of less than 20% for heat-sensitive nutrients. Furthermore, the oil content of these products is typically 10-20%, making these high-energy-density fried fruit and vegetable crisps inconsistent with the "reduced oil" dietary needs of the new generation of consumers, leading to their gradual abandonment by the market and a severe shrinkage in the market. In summary, the first-generation fruit and vegetable crisp processing technologies, such as room temperature frying and puffing, low-temperature vacuum oil bath, vacuum microwave puffing, or vacuum drying, are currently in the stage of being phased out or gradually replaced.

[0003] In recent years, freeze-drying technology has developed rapidly in the fruit and vegetable drying industry, replacing a large portion of the first-generation fruit and vegetable crisp processing capacity. Its biggest advantage lies in maintaining the material at a low temperature and low pressure throughout the drying process, resulting in a retention rate of over 70% for the nutrients and functional substances in fruits and vegetables. However, freeze-drying technology also preserves the original cellular structure of fruits and vegetables, leading to extremely high porosity. This results in products that are highly hygroscopic and prone to moisture absorption and reabsorption, exhibiting a strong stickiness when chewed. Furthermore, the thin pore walls fail to provide sufficient mechanical strength, resulting in a soft texture. These quality defects limit the further development of the freeze-drying industry. On the other hand, simply using freeze-drying technology typically requires more than 20 hours to dry a single batch of material. This long drying time leads to relatively low overall production efficiency, limiting the production capacity of freeze-drying technology. How to reduce the hygroscopicity of freeze-dried fruits and vegetables, improve their crispness, and shorten the drying time are urgent problems that need to be solved in the freeze-drying field.

[0004] To address the aforementioned problems, airflow puffing technology and equipment were developed at the beginning of this century. This technology is also known as variable-temperature pressure difference flash puffing or pressure difference flash puffing. Related utility models include processing equipment such as the vacuum pressure difference puffing machine ZL201020271094.3 and airflow puffing equipment ZL201510083822.5, as well as vacuum freeze-drying and airflow puffing integrated drying equipment ZL201620875198.2. In addition, various variable-temperature pressure difference puffing drying technologies for fruits and vegetables were developed, including ZL200610165346.2 and ZL201110049026.1, and a combined freeze-drying and pressure difference puffing drying technology ZL201310666433.6. With the maturity of the technology and equipment, airflow puffing has been rapidly and widely applied to fruits such as apple slices, banana slices, and dragon fruit slices, and the products are very popular with consumers. However, with the development of the social economy, people's demand for green, natural, and nutritious fruits and vegetables has gradually increased, and the problems with airflow puffing technology have gradually become apparent. This is mainly reflected in the following aspects: Although pressure-differential flash drying produces crispy products, airflow puffing requires a long vacuum drying period in the later stages of pressure-differential processing, resulting in a single-chamber drying time typically exceeding 4 hours. Coupled with the small volume of the chambers, a typical four-chamber drying system can only produce about 300 kg of fruit and vegetable crisps per day, resulting in extremely low equipment efficiency. Secondly, the prolonged high-temperature drying process during pre-drying, balancing, and vacuum drying stages leads to significant nutrient loss. The retention rate of heat-sensitive nutrients such as vitamin C is usually less than 20%, severely reducing the nutritional and health value of the product. This causes many consumers to view airflow puffed fruits and vegetables as "low-end products," thus hindering the development of the airflow puffing industry. As of the end of 2024, the total processing capacity of the airflow puffing industry was less than 5,000 tons.

[0005] In response to the problems of long drying time, sticky and soft texture of freeze-dried fruit and vegetable chips, as well as the problems of long drying time, small single-machine capacity and serious loss of nutrients in airflow puffing drying, there is an urgent need for a new type of fruit and vegetable chip drying equipment that is highly efficient, simple in structure, easy to operate and can better preserve the nutrients and functional substances in fruits and vegetables. Utility Model Content

[0006] One objective of this invention is to solve at least the aforementioned problems and provide a flash drying device for fruits and vegetables under instantaneous pressure difference. On the one hand, it achieves rapid heating of materials by directly introducing steam, increasing the flash evaporation power of moisture under pressure difference, and combining this with dry hot air to supplement the pressure difference power. This eliminates the time-consuming operation unit of vacuum drying in traditional airflow puffing, thus realizing rapid puffing and drying of fruit and vegetable crisps. On the other hand, this invention combines freeze-drying as a pre-drying method, and significantly improves the retention rate of nutrients in the product by shortening the heating time of the material under pressure difference treatment. This achieves a dual improvement in drying efficiency and drying quality, effectively solving the bottleneck problem in the drying of fruit and vegetable crisps, and has broad application prospects.

[0007] To achieve these objectives and other advantages according to this utility model, a fruit and vegetable instantaneous pressure difference flash drying device is provided, comprising:

[0008] Multiple material drying chambers, each material drying chamber includes a chamber body and a drive unit. One end of the chamber body is slidably sealed with a chamber door. The chamber body is equipped with a temperature monitor, a moisture detector, a pressure gauge, an exhaust port, and a drain port. The drive unit drives the chamber door to slide to open and close the chamber body.

[0009] A vacuum system includes a vacuum unit and a vacuum chamber. Each vacuum chamber is connected to the interior of each chamber via a vacuum pipe. The vacuum pipe is equipped with a pressure relief valve. The vacuum chamber is connected to the vacuuming end of the vacuum unit.

[0010] The steam generator has its steam outlet connected to the interior of each compartment.

[0011] The high-pressure dry hot air heating system has its dry hot air outlet connected to the interior of each chamber.

[0012] The control system is connected to the drive unit, the temperature monitor, the moisture detector, the pressure gauge, the vacuum unit, the steam generator, and the high-pressure dry hot air heating system.

[0013] Preferably, the silo body is horizontally arranged, the silo body door is located at one end of the silo body along its length, each silo body is provided with a steam dissipation pipe, the steam dissipation pipe is arranged along the length of the silo body, the bottom of the steam dissipation pipe is provided with a plurality of spray holes spaced apart along its length, one end of the steam dissipation pipe is closed and the other end is open;

[0014] The steam generator is connected to a first main pipe at its steam outlet. Multiple first branch pipes are connected to the main pipe. Each of the multiple first branch pipes corresponds to a multiple chamber. Each first branch pipe is equipped with a steam valve. The steam outlet of the first branch pipe is connected to the open end of the steam dissipation pipe in the corresponding chamber.

[0015] The high-pressure dry hot air heating system includes an air compressor, an air storage tank, and a heat exchanger. The air outlet of the air compressor is connected to the air inlet of the air storage tank, and the air outlet of the air storage tank is connected to the air inlet of the heat exchanger. The air outlet of the heat exchanger is connected to a second main pipe, and multiple second branch pipes are connected to the second main pipe. Each of the multiple second branch pipes corresponds to a multiple chamber. Each second branch pipe is equipped with a dry hot air valve, and the air outlet of the second branch pipe is connected to the open end of the steam dissipation pipe in the corresponding chamber.

[0016] Preferably, each compartment contains multiple steam dissipation pipes, which are spaced apart from top to bottom. The open ends of the multiple steam dissipation pipes are on the same side, and the open ends of the multiple steam dissipation pipes are connected to an inlet pipe. The inlet pipe has a pair of access holes, and the outlet ends of the first branch pipe and the second branch pipe are respectively connected to a pair of access holes in the corresponding compartment.

[0017] It also includes multiple pallet racks, each corresponding to a multiple silo. Each pallet rack includes a support frame and multiple shelves spaced apart from top to bottom on the support frame. The shelves are arranged along the length of the silo. Each shelf corresponds to a multiple steam venting pipe in the corresponding silo and is located below the corresponding steam venting pipe. Multiple material pallets are movably mounted on each shelf so that the distance between the material pallets and the shelf is 2 to 30 mm.

[0018] Preferably, it also includes a track mechanism, which includes multiple guide track components, each corresponding to a multiple compartment. Each guide track component includes a pair of external compartment tracks, a pair of internal compartment tracks, and a compartment door slide rail. The pair of external compartment tracks corresponds to the pair of internal compartment tracks, and the internal compartment tracks are located on the extension line of the corresponding external compartment tracks. The compartment door slide rail is vertically arranged between the pair of external compartment tracks and the pair of internal compartment tracks, and the external compartment tracks, internal compartment tracks, and compartment door slide rail are interconnected.

[0019] The pallet rack is equipped with electric vehicle wheels at its bottom. The electric vehicle wheels are connected to the control system. The electric vehicle wheels slide along a pair of external tracks and a pair of internal tracks to enter and exit the corresponding compartments. The compartment door slides along the compartment door track to open and close the compartment.

[0020] Preferably, the system also includes a water-catching system, which comprises a refrigeration unit, a condenser compartment, a condenser coil, and a water collector. The condenser coil is located inside the condenser compartment. The vacuum pumping end of the vacuum unit, the condenser compartment, and the vacuum chamber are connected in sequence. The cooling output end of the refrigeration unit is connected to the inlet of the condenser coil, and the outlet of the condenser coil is connected to the inlet of the refrigeration unit for recycling. The refrigeration unit is connected to the control system.

[0021] Preferably, the bottom of the condenser compartment is funnel-shaped; it also includes a water collector, which is connected to the bottom of the condenser compartment.

[0022] Preferably, an electric heating plate is installed on the top of the shelf, and the electric heating plate is coated with graphene thermal radiation material. When the material tray is placed on the tray frame, the gap between the material tray and the electric heating plate is 10mm.

[0023] Preferably, each chamber is equipped with a cold air fan, which is connected to the control system, and the exterior of the drying chamber includes an insulation layer.

[0024] Compared with existing equipment technology, this utility model abandons the traditional "pre-drying-moistening-pipeline radiation heating (equilibrium temperature)-airflow puffing" process used in traditional airflow puffing machines (variable temperature pressure difference puffing machines, pressure difference flash evaporators) for processing fruit and vegetable crisps. Instead, it introduces a "pre-drying-direct steam injection heating-instantaneous pressure difference flash evaporation" process. This utility model directly introduces high-temperature, high-pressure steam for 10-45 seconds to raise the pressure in the drying chamber to 0.2-0.6 MPa. Combined with pressurization of hot dry air, the pressure in the processing chamber can be further rapidly increased to 0.8-1.2 MPa. Under these conditions, rapid depressurization results in two main benefits: improved quality and increased processing efficiency. Specific benefits include:

[0025] 1) The instantaneous pressure difference flash drying equipment described in this utility model can significantly improve the crispness of fruit and vegetable slices, solving the problem of soft texture and poor crispness in freeze-dried fruits and vegetables. Traditional freeze-dried fruits and vegetables can usually retain the original cellular structure of the fruits and vegetables, forming a honeycomb-like porous structure. However, this dense natural cellular porous structure has a very large surface area, and coupled with the large amount of highly hydrophilic small molecule sugars (fructose, sucrose, etc.) in the fruits and vegetables, freeze-dried fruits and vegetables have extremely high hygroscopicity. Common freeze-dried apples, strawberries, mangoes, and other products quickly absorb water and clump together after entering the mouth, sticking to the surface of the teeth and making them difficult to swallow, resulting in an unpleasant taste experience. This is also the sensory quality problem of freeze-dried fruits and vegetables that is most criticized by consumers. On the other hand, due to this extremely high hygroscopicity, freeze-dried fruits and vegetables usually need to use multi-layer composite high moisture-barrier packaging materials in combination with desiccants during the distribution process to prevent the product from absorbing moisture and deteriorating during distribution and storage, which increases the production cost of the product. Reducing the hygroscopicity, removing the sticky texture, and improving the crispness of freeze-dried products are the three major quality issues that the freeze-drying industry continues to address. Regarding crispness, the crispness perceived by consumers is triggered by the collapse of the food's tissue structure, but this requires a certain stress threshold. Freeze-dried fruits and vegetables, because their pore walls are almost entirely cell walls, have extremely low mechanical strength, thus failing to provide sufficient crispness peaks when consumed. This invention uses instantaneous pressure difference flash evaporation technology to treat the pre-dried raw materials after freeze-drying, breaking down their overly regular and dense natural porous network structure to form a relatively large pore structure and suitable pore wall thickness. These newly generated pores have greater mechanical strength and can form more crispness peaks, macroscopically giving the product a crisper texture. Regarding stickiness and hygroscopicity, the principle is the same as the improvement in crispness, which is also due to changes in the microscopic pore structure. During the flash evaporation process, some cell structures are compressed to form thicker cell walls, which significantly reduces the specific surface area of ​​the material, thereby reducing the contact area between small molecule sugars and water. Macroscopically, this is reflected in a significant reduction in the product's hygroscopicity and the near absence of stickiness, with its texture and taste being close to the crispy texture of potato chips on the market.

[0026] 2) This invention employs a combination of instantaneous pressure difference flash drying, which significantly improves the retention rate of heat-sensitive nutrients in fruits and vegetables, solving the problem of high nutrient loss rates in traditional airflow puffing. Currently, common processing methods for producing fruit and vegetable chips include vacuum oil bath, vacuum microwave drying, and airflow puffing. These drying methods all require prolonged exposure of the fruit and vegetable materials to a high-temperature environment, leading to rapid loss of heat-sensitive nutrients such as vitamin C and phenolic compounds. The retention rate of these heat-sensitive nutrients is typically less than 30%. For example, the vitamin C retention rate of airflow-puffed apples is less than 20%. During airflow puffing, the material typically needs to be equilibrated at 70-110℃ for 10-15 minutes through radiant heating via pipes. After airflow puffing, due to the still high moisture content, the material needs to be vacuum-dried at 60-90℃ for 3-5 hours to be completely dried to a moisture content below 5%. Generally, the degradation of vitamin C follows a first-order kinetic model, meaning that temperature and time are two key influencing factors. Prolonged exposure to higher temperatures results in the most severe losses, while short-term exposure to high temperatures or prolonged exposure to lower temperatures is beneficial for nutrient retention. In production, freeze-drying aligns with prolonged low-temperature exposure, thus achieving high nutrient retention. This invention employs a strategy of prolonged low-temperature pre-drying (sublimation drying) followed by short-term high-temperature flash evaporation using instantaneous pressure difference. The combined retention rate of these two stages can retain over 80% of heat-sensitive functional nutrients, far exceeding the retention rate of heat-sensitive nutrients achieved by current airflow puffing equipment.

[0027] 3) This invention employs a steam jet heating and humidification process, combined with high-temperature dry air to increase the pressure difference, significantly shortening the drying time and solving the problem of long drying time in freeze-drying technology. While ensuring a high retention rate of nutrients, this invention reduces drying time by more than 50% compared to typical freeze-drying equipment. Specifically, taking typical fruits and vegetables such as freeze-dried apples, strawberries, or mangoes as examples, the average total time per compartment in commercial freeze dryers is 20-32 hours, 15-28 hours, and 25-29 hours, respectively. At the end of the sublimation drying stage, the material moisture content is approximately 20-30%, followed by the desorption drying stage. The desorption stage takes 8-12 hours for apples, 5-10 hours for strawberries, and 10-15 hours for mangoes, accounting for about half of the total drying time. However, using the equipment of this invention, after the initial sublimation drying, when the material moisture content is reduced to approximately 20-30%, the material is switched to the instantaneous pressure difference flash evaporation program. This can complete the desorption drying process, which would normally take more than 10 hours, within minutes, achieving rapid drying in the later stages. Typically, fruit and vegetable raw materials with a moisture content of 20-30% can have approximately 15-25% of their dry basis moisture content removed after instantaneous pressure difference flash evaporation, bringing the moisture content close to the minimum requirement of below 5% at the drying endpoint. Even for materials that are difficult to dry, which may still have a few to ten percent of moisture remaining, final drying can be achieved through 1-3 low-intensity instantaneous pressure difference flash evaporation processes (pressure difference 0.2-0.6 MPa, pressurization medium is dry hot air to avoid further introduction of external moisture). This supplementary drying process takes no more than 2-6 minutes. In general, using the instantaneous pressure difference flash evaporation technology of this invention, the time required for the original desorption drying stage of materials can usually be controlled within 10 minutes. Even without considering the advantage of preventing heat loss of nutritional and functional substances, the instantaneous pressure difference flash evaporation of this invention can shorten the drying time by 3-5 hours compared to typical airflow expansion equipment in terms of moisture removal efficiency. Specifically, taking the commonly used pipeline radiant heating airflow puffing equipment for processing apple slices as an example, hot air is typically used to pre-dry the material to a dry basis moisture content of 30-40%, a process that takes 4-7 hours. Moisture equalization takes at least 6-24 hours, followed by 10-20 minutes of temperature and pressure differential puffing. Finally, a longer vacuum drying time of 3-5 hours is required to reduce the moisture content to below 5% on a dry basis. Even excluding the moisture equalization time, the total drying time is over 10 hours. The steam direct injection heating and humidification process used in this invention adjusts the pre-drying moisture content to 20-30% on a dry basis.Even with hot air pre-drying, this adjustment only adds about 1 hour to the hot air pre-drying stage, but shortens the humidification and differential pressure drying stages to within 2 minutes. During this process, the moisture content drops instantly to below 5% or close to that level under the powerful flash evaporation force. Combined with 1-3 low-intensity instantaneous differential pressure flash evaporations (0.2-0.6 MPa differential pressure, pressurizing medium is dry hot air) to complete the final drying. The entire drying process takes no more than 10 minutes. The biggest advantage is that it eliminates the need for the additional vacuum drying stage required by airflow puffing technology, avoiding the time-consuming tailing stage of vacuum drying at the end. This single stage alone shortens the processing time by 3-5 hours and saves 30-50% of energy. This invention, by adopting instantaneous differential pressure flash evaporation technology based on direct steam injection heating and humidification, eliminates the need for prolonged vacuum drying in the drying chamber, as required by airflow puffing, significantly improving the utilization efficiency of the drying chamber. This lays the foundation for continuous production of the equipment, and this improvement greatly enhances the production efficiency of fruit and vegetable crisps.

[0028] 4) This utility model equipment enables continuous production of fruit and vegetable pressure differential flash evaporation, significantly improving the production capacity of fruit and vegetable chip processing lines. Currently, small production capacity is a bottleneck factor restricting the expansion of fruit and vegetable airflow puffing production lines. Taking the most commonly used airflow puffing equipment in the industry as an example (such as the DQPH-5 type variable temperature pressure differential puffing equipment), large-scale production equipment generally has a vacuum tank connected to a maximum of 4 drying chambers. Each drying chamber can dry about 25 kg of semi-dried apple chips with a dry basis moisture content of about 30% per batch. After drying them to a dry basis moisture content of less than 5%, the finished apple chips obtained are at most 20 kg. The total weight of the products from 4 chambers is about 80 kg. Assuming that each chamber takes 4 hours to dry a batch of semi-dried raw materials, and considering the heating, cooling, and feeding / discharging time, each chamber can process a maximum of 4 batches of raw materials per day. The total daily production capacity of a one-to-four (one vacuum chamber connected to 4 drying chambers) airflow puffing equipment is about 320 kg of apple chips. This new type of equipment employs instantaneous pressure difference flash evaporation technology based on direct steam injection heating and humidification. The direct steam injection and pressure difference flash evaporation processing time for a single chamber is less than 1 minute. Considering the feeding and discharging time and the additional pulsed pressure difference flash evaporation drying time based on dry hot air heating and pressurization required for some samples, the processing time for a single batch of materials does not exceed 10 minutes. Therefore, at least 6 chambers can be processed per hour. Calculated based on an initial moisture content of 20% for the raw materials, 25 kg of material per chamber can typically produce more than 21 kg of finished apple chips. Therefore, the processing capacity of a single chamber per hour is approximately 210 kg. Based on 20 hours of operation per day, the processing capacity of a single chamber reaches 4.2 tons. With one vacuum chamber and four drying chambers, the total daily processing capacity exceeds 16 tons. Conservatively calculated, the processing capacity is more than 50 times that of traditional airflow differential puffing equipment. The premise for the continuous and rapid turnover production of the drying chamber in this utility model is not only the significant reduction in the time of the differential pressure flash evaporation process, but also the design of an intelligent feeding and discharging system, supplemented by large-scale pre-drying equipment such as external freeze-drying, hot air, and heat pumps, to achieve a moisture content of 20-30%. Typically, a 200-square-meter freeze-drying chamber can process two chambers of semi-dry raw materials with a dry basis moisture content of approximately 20% per day, with an input of approximately 2.5 tons per chamber and a daily semi-dry raw material production capacity of approximately 800 kg per chamber. Therefore, a single one-to-four instantaneous differential pressure flash evaporation system can match the production scale of 20 external 200-square-meter freeze-drying chambers. The pre-drying operation unit, which reduces the raw material moisture content to approximately 20-30%, can be separated from the instantaneous differential pressure flash evaporation process of this equipment in terms of processing time and space. Alternatively, semi-finished raw materials with this specific moisture content can be purchased, further improving production flexibility and processing efficiency.

[0029] 5) This utility model's equipment utilizes direct steam contact with materials, significantly improving the uniformity of product quality such as moisture content and texture. The heating rate of materials via high-temperature, high-pressure steam is extremely rapid, typically raising the material temperature to 110-180℃ within seconds to tens of seconds. Due to the anisotropic nature of steam, the heating and humidification of the materials are highly uniform, significantly improving the uniformity of the material's puffing quality. Currently, airflow puffing uses pipeline radiant heating, resulting in a 5-10℃ temperature difference between the steam pipe inlet and outlet. This causes significant differences in the flash evaporation dynamics, leading to uneven moisture content after flash evaporation in materials located in different parts of the tray. If subsequent dehydration is performed according to the standard of hot air drying for all samples, some samples in the low-temperature zone of the tray will exhibit browning due to high temperature, reducing the overall product quality.

[0030] 6) This utility model equipment adopts a steam jet heating process, which can reduce the size of the equipment and lower the manufacturing cost. Directly injecting high-temperature, high-humidity steam not only rapidly raises the temperature of the drying chamber but also instantly increases the pressure inside the drying chamber to 0.2-0.6 MPa. Simultaneously, by further adding hot dry air, the pressure in the drying chamber can be increased to 0.8-1.2 MPa. This increased pressure significantly increases the flash kinetic energy of moisture within the material, allowing for a greater and faster removal of moisture in a single flash. Due to the increased flash kinetic energy caused by the increased pressure, the volume ratio of the vacuum chamber to the drying chamber can be reduced to 6-10:1, far less than the 10-20:1 or higher volume ratio required by conventional variable-temperature pressure differential expansion and airflow expansion machines. This significantly reduces the volume of the vacuum chamber and the amount of steel used, thus significantly reducing the equipment manufacturing cost.

[0031] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the instantaneous pressure difference flash drying equipment for fruits and vegetables according to one of the technical solutions of this utility model;

[0033] Figure 2 This is a schematic diagram of the structure of the condenser chamber and water collector according to one of the technical solutions of this utility model;

[0034] Figure 3 This is a top view schematic diagram of the structure of the external warehouse track, the warehouse door track, and the internal warehouse track according to one of the technical solutions of this utility model;

[0035] Figure 4 This is a schematic diagram of the structure of the tray rack placed in the drying chamber according to one of the technical solutions of this utility model.

[0036] Figure Descriptions: 1-Drying Chamber; 2-Chamber Door; 3-Chamber Door Rail; 4-Viewing Window; 5-Temperature Monitor; 6-Moisture Detector; 8-Drain Outlet; 7-Pressure Gauge; 9-Water Ring Pump; 10-Roots Pump; 11-Vacuum Pipeline; 12-Condenser Chamber; 13-Vacuum Chamber; 14-Pressure Relief Valve; 15-First Main Pipeline; 16-Steam Valve; 17-Air Compressor; 18-Air Tank; 19-Heat Exchanger; 20-Dry Hot Air Valve; 21-Second Main Pipeline; 22-Nozzle; 23-Exhaust Outlet; 24-Refrigeration Unit; 25-Condenser Coil; 26-Water Collector; 27-Pressure Conversion Valve; 28-Vacuum Relief Valve; 30-Drain Valve; 32-Material Tray; 33-Tray Rack; 35-External Rail; 36-Internal Rail; 38-Steam Generator; 39-Steam Dissipation Pipeline. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0038] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0039] like Figure 1-4 As shown, this utility model provides a flash drying device for fruits and vegetables under instantaneous pressure difference, comprising:

[0040] Multiple material drying chambers 1, each material drying chamber 1 includes a chamber body and a driving component. One end of the chamber body is slidably sealed with a chamber door 2. The chamber body is equipped with a temperature monitor 5, a moisture detector 6, a pressure gauge 7, an exhaust port 23, and a drain port 8. The driving component drives the chamber door 2 to slide to open and close the chamber body.

[0041] The vacuum system includes a vacuum unit and a vacuum chamber 13. The vacuum chamber 13 is connected to the interior of each chamber through a vacuum pipe 11. The vacuum pipe 11 is equipped with a pressure relief valve 14. The vacuum chamber 13 is connected to the vacuuming end of the vacuum unit.

[0042] Steam generator 38, whose steam outlet is connected to the interior of each compartment;

[0043] The high-pressure dry hot air heating system has its dry hot air outlet connected to the interior of each chamber.

[0044] The control system is connected to the drive unit, the temperature monitor 5, the moisture detector 6, the pressure gauge 7, the vacuum unit, the steam generator 38, and the high-pressure dry hot air heating system.

[0045] In the above technical solution, the equipment includes multiple horizontally arranged elongated material drying chambers 1. Each drying chamber 1 includes a chamber body with a rectangular cross-section, which can be welded from 304 stainless steel plates. A sliding chamber door 2 is installed at one end of the chamber body. The chamber door 2 is driven to slide by a drive component, thereby opening or closing the chamber body. The drive component can be a cylinder, and the drive end of the cylinder is connected to the chamber door 2. A silicone rubber sealing strip is provided on the edge of the chamber door 2. The chamber body is equipped with a temperature monitor 5, a moisture detector 6, a pressure gauge 7, and a viewing window 4. The temperature monitor 5 can be a platinum resistance temperature monitor 5, the moisture detector 6 can be a near-infrared moisture detector or a low-field nuclear magnetic resonance rapid moisture detector, and the pressure gauge 7 can be a Bourdon tube pressure gauge 7. An exhaust port 23 is provided at the top of the chamber body, and a drain port 8 is provided at the bottom.

[0046] The vacuum system includes a vacuum unit and a vacuum chamber 13. The vacuum chamber 13 is connected in parallel to each drying chamber 1 through multiple stainless steel vacuum pipes 11. Each vacuum pipe 11 is equipped with a pneumatic butterfly valve as a pressure relief valve 14 near the chamber end. The vacuum unit uses a Roots pump 10 connected in series with a water ring pump 9. The volume of the vacuum chamber 13 can be several times the volume of the drying chamber 1, such as 6 to 8 times, depending on the actual number of drying chambers 1 used and the drying requirements.

[0047] The steam generator 38 is a device that can produce high-temperature and high-pressure steam, such as a steam boiler that produces high-temperature and high-pressure steam. Its steam outlet port is connected to a first main pipe 15. Multiple first branch pipes are connected in parallel on the first main pipe 15. The multiple first branch pipes correspond one-to-one with multiple chambers. The first branch pipe is connected to the corresponding chamber to supply high-temperature and high-pressure steam to the corresponding chamber. Each first branch pipe is equipped with a steam valve 16 to individually control the supply of high-temperature and high-pressure steam to the corresponding chamber. The steam valve 16 can be an electric valve.

[0048] The high-pressure dry hot air system is a relatively mature existing technology. For example, it may include an air compressor 17 and a heat exchanger 19. The heat exchanger 19 may be a plate heat exchanger. The air outlet of the air compressor 17 is connected to the air inlet of the plate heat exchanger 19. The air outlet of the plate heat exchanger 19 is connected to a second main pipe 21. Multiple second branch pipes are connected in parallel on the second main pipe 21. The multiple second branch pipes correspond one-to-one with multiple chambers. The second branch pipes are connected to the corresponding chambers to supply high-pressure dry hot air to the corresponding chambers. Each second branch pipe is equipped with a dry hot air valve 20 to individually control the supply of high-pressure dry hot air to the corresponding chamber. The dry hot air valve 20 may be an electric valve.

[0049] The control system can be a PLC control system. The vacuum unit, the steam generator 38, the high-pressure dry hot air heating system, the drive unit, the temperature monitor 5, the pressure gauge 7, the moisture detector 6, the steam valve 16, the dry hot air valve 20, and the pressure relief valve 14 are all connected to the control system to transmit monitoring information to the control system or receive instructions from the control system to perform corresponding actions.

[0050] In the above technical solution, during equipment operation, the control system starts the vacuum unit and opens the pressure relief valve 14, reducing the pressure in drying chamber 1 to below 0.1 kPa before closing the pressure relief valve 14. After opening the steam valve 16, high-temperature and high-pressure steam is injected into the chamber through the pipeline, raising the chamber pressure to 0.2–0.6 MPa. Immediately after closing the steam valve 16, the dry hot air valve 20 is opened, injecting high-pressure dry hot air to raise the chamber pressure to 0.8–1.2 MPa. After opening the pressure relief valve 14, the chamber pressure drops sharply to below 0.5 kPa within 2 seconds, completing the flash evaporation. The moisture analyzer 6 monitors the material in real time. If the dry basis moisture content is higher than 5%, the dry hot air pressurization and flash evaporation operation is initiated until the dry basis moisture content of the material is lower than 5%.

[0051] The beneficial effects of adopting this technical solution are that the rectangular cross-section silo body, combined with the sliding silo door 2, achieves reliable sealing and meets the requirements of high-pressure conditions. The coordinated operation of multiple systems can quickly establish a pressure gradient (0.1 kPa → 1.0 MPa), and the pressure relief rate ≥ 0.6 MPa / s ensures effective flash evaporation. The control system automatically triggers supplementary drying processes based on moisture feedback, ensuring that the final moisture content is stably controlled below 5%. The overall structure provides a feasible equipment foundation for instantaneous pressure differential flash evaporation of fruits and vegetables. Furthermore, the dried material (fruit and vegetable slices) is not only brittle but also exhibits less loss of heat-sensitive nutrients (high vitamin C content). In addition, the synergistic use of high-temperature, high-pressure steam heating and high-pressure dry hot air heating results in better drying effects and higher quality fruit and vegetable slices.

[0052] In another technical solution, the silo body is horizontally arranged, the silo door 2 is located at one end of the silo body along its length, each silo body is provided with a steam dissipation pipe 39, the steam dissipation pipe 39 is arranged along the length of the silo body, the bottom of the steam dissipation pipe 39 is provided with a plurality of spray holes 22 spaced apart along its length, one end of the steam dissipation pipe 39 is closed and the other end is open.

[0053] The steam generator 38 has a steam outlet end connected to a first main pipe 15. The first main pipe 15 has multiple first branch pipes connected to it. Each of the multiple first branch pipes corresponds to a multiple chamber. Each first branch pipe is equipped with a steam valve 16. The steam outlet end of the first branch pipe is connected to the open end of the steam dissipation pipe 39 in the corresponding chamber.

[0054] The high-pressure dry hot air heating system includes an air compressor 17, an air storage tank 18, and a heat exchanger 19. The air outlet of the air compressor 17 is connected to the air inlet of the air storage tank 18, and the air outlet of the air storage tank 18 is connected to the air inlet of the heat exchanger 19. The air outlet of the heat exchanger 19 is connected to a second main pipe 21, and multiple second branch pipes are connected to the second main pipe 21. The multiple second branch pipes correspond one-to-one with multiple chambers. Each second branch pipe is equipped with a dry hot air valve 20, and the air outlet of the second branch pipe is connected to the open end of the steam dissipation pipe 39 in the corresponding chamber.

[0055] In the above technical solution, each chamber is provided with a stainless steel steam duct 39 along its length. Spray holes 22 are spaced apart at the bottom of the steam duct 39. One end of the steam duct 39 is closed, and the other end is open. The high-pressure dry hot air system includes: an air compressor 17, an air tank 18, and a plate heat exchanger 19. The outlet of the air compressor 17 is connected to the inlet of the air tank 18, and the outlet of the air tank 18 is connected to the inlet of the plate heat exchanger 19. The outlet of the plate heat exchanger 19 is connected to the second main pipe 21.

[0056] Each of the first and second pipes is connected to the open end of the steam venting pipe 39 in the corresponding compartment, so as to inject high-temperature and high-pressure steam and high-pressure dry hot air into the compartment through the steam venting pipe 39 and the nozzle 22.

[0057] The beneficial effects of this technical solution are that the horizontally arranged steam duct 39, in conjunction with the bottom array of nozzles 22, ensures uniform diffusion of steam and hot dry air along the length of the chamber. The shared duct interface for steam and hot dry air simplifies the structure, and rapid medium replacement is achieved through valve switching. This structure provides a uniform temperature and pressure environment for differential flash evaporation.

[0058] In another technical solution, there are multiple steam dissipation pipes 39 in each compartment. The multiple steam dissipation pipes 39 are arranged at intervals from top to bottom. The open ends of the multiple steam dissipation pipes 39 are on the same side, and the open ends of the multiple steam dissipation pipes 39 are connected to an inlet pipe. The inlet pipe has a pair of access holes. The air outlets of the first branch pipe and the second branch pipe are respectively connected to a pair of access holes in the corresponding compartment.

[0059] It also includes multiple pallet racks 33, which correspond one-to-one with multiple silos. Each pallet rack 33 includes a support and multiple shelves arranged at intervals from top to bottom on the support. The shelves are arranged along the length of the silo. Each shelf corresponds one-to-one with multiple steam venting pipes 39 in the corresponding silo and the shelf is located below the corresponding steam venting pipe 39. Multiple material pallets 32 are movably mounted on each shelf so that the distance between the material pallets 32 and the shelf is 2 to 30 mm.

[0060] In the above technical solution, each drying chamber 1 is provided with multiple steam dissipation pipes 39 from top to bottom. The open ends of the multiple steam dissipation pipes 39 are located on the same side and are interconnected by an inlet pipe. The inlet pipe is vertically arranged and closed at both ends. The middle two sides of the inlet pipe are respectively provided with access holes. A pair of access holes correspond one-to-one with the first branch pipe and the second branch pipe corresponding to the chamber body. The air outlet ends of the first branch pipe and the second branch pipe are connected to the access holes respectively.

[0061] There are multiple pallet racks 33, each corresponding to a different silo. Each pallet rack 33 includes a support frame and multiple shelves. The shelves are arranged at intervals from top to bottom on the support frame and are arranged along the length of the silo. Multiple material trays 32 are movably mounted on the shelves. The distance between the bottom of the material tray 32 and the shelf is 2-30mm. Specifically, multiple sets of support rods can be provided on the shelf, each corresponding to a different material tray 32. The material tray 32 is usually square, with a recessed center for holding materials. The four corners of the bottom edge of the square are provided with mounting holes. Each set of support rods includes four rods corresponding to the four mounting holes. When the material tray 32 is placed on the corresponding set of support rods, the distance between the bottom of the material tray 32 and the shelf is 2-30mm. Multiple perforations can also be made on the shelf to allow steam to pass through.

[0062] In this technical solution, high-temperature and high-pressure steam / high-pressure dry hot air is diverted from the corresponding first branch pipe / second branch pipe through the inlet pipe to the steam dissipation pipe 39, and sprayed downward through the nozzle 22 to uniformly heat the fruit and vegetable slices in the material tray 32.

[0063] The beneficial effects of adopting this technical solution are that the multi-layered steam dissipation pipes 39 and the pallet rack 33 are designed in a corresponding layered manner to achieve uniform heat distribution in the height direction of the silo. There is a gap of 2 to 30 mm between the material pallet 32 ​​and the shelf, which can prevent condensate from accumulating at the bottom of the pallet and ensure that the airflow covers all materials.

[0064] In another technical solution, a track mechanism is also included. The track mechanism includes multiple guide track components, each corresponding to a multiple compartment. Each guide track component includes a pair of external compartment tracks 35, a pair of internal compartment tracks 36, and a compartment door slide rail 3. The pair of external compartment tracks 35 corresponds to the pair of internal compartment tracks 36, and the internal compartment tracks 36 are located on the extension line of the corresponding external compartment tracks 35. The compartment door slide rail 3 is vertically arranged between the pair of external compartment tracks 35 and the pair of internal compartment tracks 36, and the external compartment tracks 35, internal compartment tracks 36, and compartment door slide rail 3 are interconnected.

[0065] The pallet frame 33 is equipped with electric vehicle wheels at its bottom. The electric vehicle wheels are connected to the control system. The electric vehicle wheels slide along a pair of external tracks 35 and a pair of internal tracks 36 to enter and exit the corresponding compartment. The compartment door 2 slides along the compartment door 2 track to open and close the compartment.

[0066] In the above technical solution, the track mechanism includes multiple guide track components, each of which consists of a pair of external tracks 35, a pair of internal tracks 36, and a door slide rail 3. The external tracks 35 and internal tracks 36 are laid horizontally and coaxially with a spacing error of ≤1mm; the door slide rail 3 is vertically welded between the two, and the intersection of the three tracks is interconnected (as shown in the figure). Four electric wheels (which can be driven by DC geared motors) are installed at the bottom of the pallet frame 33. The wheels are connected to the PLC control system via a CAN bus. A slider is fixed at the bottom of the door 2, and the slider is embedded in the door slide rail 3 and is driven to move horizontally by a cylinder; preferably, the diameter of the electric wheel is larger than the width of the door slide rail 3.

[0067] In the above technical solution, during feeding: the control system drives the pallet frame 33 electric wheels to travel along the outer track 35 to the intersection of the bin door slide rail 3 → the cylinder pulls the bin door 2 to slide and open along the slide rail → the wheels pass through the bin door slide rail 3 and enter the inner track 36 → after traveling to the set position, the bin door 2 closes (sealing pressure ≥ 0.2 MPa). The discharging process is the reverse operation. The entire process can be programmed and controlled by PLC to achieve intelligent control;

[0068] The beneficial effects of adopting this technical solution are that the orthogonal layout of the track mechanism solves the problem of non-interference between the movement of the pallet frame 33 and the sliding of the door 2; the positioning accuracy of the electric wheel is controlled within ±2mm, meeting the sealing requirements of the gap between the door 2 and the track (design value ≤0.5mm). The cylinder-driven opening and closing of the door 2 and the movement of the wheels work in coordination, avoiding positioning deviations caused by manual intervention. This structure provides a mechanized basis for the rapid turnover of the drying chamber 1.

[0069] In another technical solution, a water-catching system is also included. The water-catching system includes a refrigeration unit 24, a condenser chamber 12, a condenser coil 25, and a water collector 26. The condenser coil 25 is located inside the condenser chamber 12. The vacuum pumping end of the vacuum unit, the condenser chamber 12, and the vacuum chamber 13 are connected in sequence. The cooling output end of the refrigeration unit 24 is connected to the inlet of the condenser coil 25, and the outlet of the condenser coil 25 is connected to the inlet of the refrigeration unit 24 for recycling. The refrigeration unit 24 is connected to the control system.

[0070] The bottom of the condenser chamber 12 is funnel-shaped; it also includes a water collector 26, which is connected to the bottom of the condenser chamber 12.

[0071] In the above technical solution, the water capture system includes a refrigeration unit 24, a condenser chamber 12, a spiral coil condenser, and a water collector 26. The condenser chamber 12 has an air inlet at the top and an air outlet at the bottom. The vacuum pumping end of the vacuum unit is connected to the air outlet of the condenser chamber 12 through a first connecting pipe. The air inlet of the condenser chamber 12 is connected to the vacuum chamber 13 through a second connecting pipe. A pressure switching valve 27 is provided on the second connecting pipe.

[0072] The refrigerant supply end of the refrigeration unit 24 is connected to the inlet of the spiral finned condenser coil 25 inside the condenser compartment 12 by brazing a copper pipe, and the coil outlet is connected to the suction end of the refrigeration unit 24 through the return gas pipeline to form a closed-loop circulation of refrigerant.

[0073] The bottom of the condenser chamber 12 is machined into a conical funnel (preferably with a cone angle ≥60°), and the inner wall is polished to Ra≤0.8μm to facilitate water flow; the water collector 26 is a volumetric tank, which is connected to the bottom of the condenser chamber 12 funnel through a flange pipe. An ANSI VI-level sealed pneumatic ball valve is installed in the middle of the flange pipe. The water collector 26 can have an exhaust port at the top and a drain port at the bottom. A venting valve 28 is installed at the exhaust port, and a drain valve 30 is installed at the drain port. A liquid level sensor can be installed inside the water collector 26.

[0074] The pressure switching valve 27, the refrigeration unit 24, the venting valve 28, the drain valve 30, and the liquid level sensor are all connected to the PLC control system.

[0075] During operation, the hot and humid air discharged from the drying chamber 1 enters the condenser chamber 12. When it comes into contact with the surface of the condenser coil 25, the water vapor condenses into liquid water and flows into the water collector 26 along the funnel wall. The dry and cold air is drawn away by the vacuum unit. The refrigerant continuously circulates in the coil to maintain the low temperature. When the liquid level reaches 80% of the volume, the liquid level sensor is triggered, the drain is opened, and the water is drained quickly. After the water is drained, the drain is automatically closed. If the pressure of the condenser chamber 12 is greater than 10 kPa, the power of the refrigeration unit 24 is increased by 20% to enhance condensation.

[0076] The beneficial effects of adopting this technical solution are that it can quickly remove condensate from the low temperature zone, avoid the vacuum fluctuation caused by the reheating and evaporation of accumulated water, and at the same time intercept most of the liquid water to prevent liquid water from entering the vacuum unit and causing malfunctions. Combined with automatic drainage, the system energy efficiency ratio can be improved by 15-20%.

[0077] In another technical solution, an electric heating plate is installed on the top of the shelf, and the electric heating plate is coated with graphene thermal radiation material. When the material tray 32 is placed on the tray frame 33, the gap between the material tray 32 and the electric heating plate is 10mm.

[0078] In the above technical solution, the electric heating plate is connected to the control system, and heating or not heating is selected according to the actual situation. When heating is selected, the pre-frozen fruit and vegetable slices are placed on the material tray 32 and sent into the drying chamber 1. Then, the material is sublimated and dried by the electric heating plate. In this way, the equipment required for the freeze-drying process can be integrated into one set of equipment, and the two processes of freeze-drying and instantaneous pressure difference flash drying can be completed in one set of equipment, which is the so-called "freeze-drying-instantaneous pressure difference flash drying combined dryer", and its application prospects are more optimistic.

[0079] In another technical solution, each chamber is equipped with a cold air fan, which is connected to the control system. The exterior of the drying chamber 1 includes an insulation layer. The beneficial effect of this technical solution is that by designing the cold air fan, the insulation layer, and combining it with the aforementioned electric heating plate, the equipment required for the pre-freezing and freeze-drying stages can be integrated into one set of equipment. The three stages of quick-freezing, freeze-drying, and instantaneous pressure difference flash drying can be completed in one set of equipment, which is the so-called "quick-freezing-freeze-instantaneous pressure difference flash drying integrated machine", thus improving the practicality of the device.

[0080] The number of devices and processing capacity described herein are for simplification. Applications, modifications, and variations of the present invention's instantaneous pressure differential flash drying equipment for fruits and vegetables will be readily apparent to those skilled in the art.

[0081] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A flash drying device for fruits and vegetables under instantaneous pressure difference, characterized in that, include: Multiple material drying chambers, each material drying chamber includes a chamber body and a drive unit. One end of the chamber body is slidably sealed with a chamber door. The chamber body is equipped with a temperature monitor, a moisture detector, a pressure gauge, an exhaust port, and a drain port. The drive unit drives the chamber door to slide to open and close the chamber body. A vacuum system includes a vacuum unit and a vacuum chamber. The vacuum chamber is connected to the interior of each chamber via a vacuum pipe. The vacuum pipe is equipped with a pressure relief valve. The vacuum chamber is connected to the vacuum pumping end of the vacuum unit. The steam generator has its steam outlet connected to the interior of each compartment. The high-pressure dry hot air heating system has its dry hot air outlet connected to the interior of each chamber. The control system is connected to the drive unit, the temperature monitor, the moisture detector, the pressure gauge, the vacuum unit, the steam generator, and the high-pressure dry hot air heating system.

2. The instantaneous pressure difference flash drying equipment for fruits and vegetables as described in claim 1, characterized in that, The silo is horizontally arranged, and the silo door is located at one end of the silo along its length. Each silo is equipped with a steam dissipation pipe, which is arranged along the length of the silo. The bottom of the steam dissipation pipe is provided with multiple spray holes spaced apart along its length. One end of the steam dissipation pipe is closed and the other end is open. The steam generator's steam outlet is connected to a first main pipe, which is connected to multiple first branch pipes. Each of the multiple first branch pipes corresponds to a multiple chamber. Each first branch pipe is equipped with a steam valve, and the steam outlet of the first branch pipe is connected to the open end of the steam dissipation pipe in the corresponding chamber. The high-pressure dry hot air heating system includes an air compressor, an air storage tank, and a heat exchanger. The air outlet of the air compressor is connected to the air inlet of the air storage tank, and the air outlet of the air storage tank is connected to the air inlet of the heat exchanger. The air outlet of the heat exchanger is connected to a second main pipe, and multiple second branch pipes are connected to the second main pipe. Each of the multiple second branch pipes corresponds to a multiple chamber. Each second branch pipe is equipped with a dry hot air valve, and the air outlet of the second branch pipe is connected to the open end of the steam dissipation pipe in the corresponding chamber.

3. The instantaneous pressure difference flash drying equipment for fruits and vegetables as described in claim 2, characterized in that, Each compartment contains multiple steam dissipation pipes, which are spaced apart from top to bottom. The open ends of the multiple steam dissipation pipes are on the same side, and the open ends of the multiple steam dissipation pipes are connected to an inlet pipe. The inlet pipe has a pair of access holes. The outlet ends of the first branch pipe and the second branch pipe are respectively connected to a pair of access holes in the corresponding compartment. It also includes multiple pallet racks, each corresponding to a multiple silo. Each pallet rack includes a support frame and multiple shelves spaced apart from top to bottom on the support frame. The shelves are arranged along the length of the silo. Each shelf corresponds to a multiple steam venting pipe in the corresponding silo and is located below the corresponding steam venting pipe. Multiple material pallets are movably mounted on each shelf so that the distance between the material pallets and the shelf is 2 to 30 mm.

4. The instantaneous pressure difference flash drying equipment for fruits and vegetables as described in claim 3, characterized in that, It also includes a track mechanism, which includes multiple guide track components, each corresponding to a multiple compartment. Each guide track component includes a pair of external compartment tracks, a pair of internal compartment tracks, and a compartment door slide rail. The pair of external compartment tracks corresponds to the pair of internal compartment tracks, and the internal compartment tracks are located on the extension line of the corresponding external compartment tracks. The compartment door slide rail is vertically arranged between the pair of external compartment tracks and the pair of internal compartment tracks, and the external compartment tracks, internal compartment tracks, and compartment door slide rail are interconnected. The pallet frame is equipped with electric vehicle wheels at its bottom. The electric vehicle wheels are connected to the control system. The electric vehicle wheels slide along a pair of external tracks and a pair of internal tracks to enter and exit the corresponding compartments. The compartment door slides along the compartment door track to open and close the compartment.

5. The instantaneous pressure difference flash drying equipment for fruits and vegetables as described in claim 4, characterized in that, It also includes a water-catching system, which comprises a refrigeration unit, a condenser chamber, and a condensing coil. The condensing coil is located inside the condenser chamber. The vacuum pumping end of the vacuum unit, the condenser chamber, and the vacuum chamber are connected in sequence. The cooling output end of the refrigeration unit is connected to the inlet of the condensing coil, and the outlet of the condensing coil is connected to the inlet of the refrigeration unit for recycling. The refrigeration unit is connected to the control system.

6. The instantaneous pressure difference flash drying equipment for fruits and vegetables as described in claim 5, characterized in that, The bottom of the condenser compartment is funnel-shaped; it also includes a water collector, which is connected to the bottom of the condenser compartment.

7. The instantaneous pressure difference flash drying equipment for fruits and vegetables as described in claim 6, characterized in that, An electric heating plate is installed on the top of the shelf. The electric heating plate is coated with graphene thermal radiation material. When the material tray is placed on the tray frame, the gap between the material tray and the electric heating plate is 10mm.

8. The instantaneous pressure difference flash drying equipment for fruits and vegetables as described in claim 7, characterized in that, Each chamber is equipped with a cold air fan, which is connected to the control system. The exterior of each drying chamber includes an insulation layer.

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