A low-temperature combined drying device and method for rehydrated prefabricated dishes

Abstract

The present application belongs to the technical field of intelligent preparation of pre-prepared dishes, and particularly relates to a low-temperature combined drying device and method for rehydrated pre-prepared dishes, comprising a shaping unit, a transfer unit and a freeze-drying unit; the shaping unit is arranged at the upper end of the transfer unit and is used for low-temperature freezing and drying shaping of food materials; the freeze-drying unit is arranged at the lower end of the transfer unit and is used for low-temperature vacuum dehydration of the food materials; the transfer unit is in communication with the shaping unit at the upper end and in communication with the freeze-drying unit at the lower end, and a movable partition assembly is arranged in the middle part; the transfer unit is used for forming a channel for transferring the food materials from the shaping unit to the freeze-drying unit inside the combined drying device. The present application aims to solve the problems of pre-prepared dishes in storage conditions, nutritional components, edible taste, and loss of nutrients during the preparation process, high energy consumption, difficulty in shaping, and hygiene and safety.

Description

Technical Field

[0001] This invention belongs to the field of intelligent preparation technology of pre-prepared vegetables, and particularly relates to a low-temperature combined drying device and method for rehydrated pre-prepared vegetables. Background Technology

[0002] Pre-cooked dishes are a product of the food industry, also known as pre-prepared foods. They generally refer to semi-finished or finished dishes made from various agricultural, livestock, poultry, and aquatic products as raw and auxiliary materials, seasonings and other auxiliary materials (including food additives), and processed through pre-selection, preparation, cooking and other processes.

[0003] Based on storage conditions, common ready-made meals on the market currently include frozen ready-made meals and room-temperature ready-made meals. Frozen ready-made meals require the semi-finished ingredients to be flash-frozen at low temperatures to preserve their nutritional components, but they also require low-temperature environments for transportation and storage, undoubtedly increasing costs and making them difficult to preserve in outdoor conditions. Room-temperature ready-made meals require the semi-finished ingredients to be sterilized at high temperatures to extend their shelf life, but high temperatures not only destroy the nutrients in the ingredients but also cause them to lose their original texture, thus reducing the quality of the ready-made meals. Furthermore, neither flash-freezing nor high-temperature sterilization methods are suitable for fruits and vegetables. After being flash-frozen and thawed, the internal structure of fruits and vegetables is damaged, making them more prone to spoilage and affecting their taste. High temperatures can also cause fruits and vegetables to soften, rot, or even dissolve. Therefore, existing ready-made meals rarely include fruits and vegetables, resulting in a relatively limited nutritional profile.

[0004] In practice, it has been found that vacuum drying pre-cooked meals at low temperatures can retain the nutritional components of the ingredients to the greatest extent without damaging their internal structure. The dried pre-cooked meals have a moisture content of less than 5%, making it difficult for microorganisms to survive and resulting in a longer shelf life. Since high-temperature sterilization and simple quick-freezing are not required, the internal structure of fruits and vegetables in the pre-cooked meals remains unaffected. The dried pre-cooked meals are small in size and lightweight, allowing for room temperature storage and saving significant transportation costs. When ready to eat, simply rehydrate the dried pre-cooked meals; this is convenient and quick, making them suitable for environments where low-temperature storage conditions cannot be guaranteed. Therefore, preparing ingredients into this type of rehydrated pre-cooked meal can solve the problems associated with quick-frozen and room-temperature pre-cooked meals.

[0005] Existing freeze-drying equipment is typically used for low-temperature vacuum drying of fresh fruits and vegetables. It rapidly freezes the ingredients while simultaneously using a vacuum pump to create a high vacuum inside the equipment, causing the moisture in the food to sublimate directly from solid ice into gaseous water vapor and be expelled. The advantages of freeze dryers lie in their ability to directly sublimate the moisture in food into a gaseous state under low-temperature, vacuum conditions, thus preserving the original structure and properties of the food and avoiding side effects such as concentration, foaming, and oxidation, ensuring the purity and high quality of the food. Furthermore, by quickly and effectively removing moisture from food, freeze dryers can maintain its nutritional components, reduce the growth environment and biological activity of bacteria and mold, thereby extending the shelf life of the food.

[0006] However, there are still many problems with using freeze dryers to directly dry rehydrated pre-cooked meals at low temperatures. First, pre-cooked meals are in a solid-liquid mixture before drying; directly putting them into the freeze dryer results in a phenomenon where the outside dries faster than the inside, leading to long drying times and high energy consumption. Second, rehydrated pre-cooked meals need to be packaged in blocks, and it is difficult to cut and package them into pieces after they have been dried as a whole. Third, pre-cooked meals in a solid-liquid mixture are prone to microbial growth when exposed to the external environment for extended periods, affecting their shelf life and food safety. Summary of the Invention

[0007] This invention provides a low-temperature combined drying device and method for rehydrated pre-prepared vegetables, which can solve the problems mentioned above regarding storage conditions, nutritional components, taste, nutrient loss during preparation, high energy consumption, difficulty in shaping, and hygiene and safety of pre-prepared vegetables. Details are as follows:

[0008] A low-temperature combined drying device for rehydrated pre-prepared vegetables includes a shaping unit, a transfer unit, and a freeze-drying unit;

[0009] The shaping unit is located at the upper end of the transfer unit and includes a shaping section with several vertically penetrating grids; the shaping unit is used for low-temperature freezing and drying shaping of food ingredients;

[0010] The freeze-drying unit is located at the lower end of the transfer unit and is used for low-temperature vacuum dehydration of the food.

[0011] The transfer unit is connected to the shaping unit at its upper end and to the freeze-drying unit at its lower end, and a movable partition assembly is provided in the middle. The transfer unit is used to form a channel inside the combined drying device for transferring food from the shaping unit to the freeze-drying unit.

[0012] Furthermore, the shaping unit includes a top cover, an upper housing, and a refrigeration and drying system;

[0013] The upper cover has one edge hinged to one edge of the upper end face of the upper box body, and a sealing ring is formed around the four edges of the lower end face; a locking mechanism is provided between the upper cover and the upper box body;

[0014] The refrigeration and drying system is located outside the upper chamber and communicates with the interior of the upper chamber, and is used to provide cold energy and wind energy to the shaping unit.

[0015] The shaping part is located inside the upper housing.

[0016] Furthermore, the refrigeration and drying system includes an exhaust fan installed on the side wall of the upper housing.

[0017] Furthermore, the transfer unit includes a middle box with slots on its side end face; the partition assembly is horizontally movable inside the middle box through the slots; the upper and lower end faces of the partition assembly are provided with corresponding sealing gaskets that fit tightly against the lower end face of the shaping part and the upper end face of the freeze-drying unit.

[0018] Furthermore, the transfer unit also includes a translation transmission unit and a translation drive unit; the translation transmission unit is disposed between the middle housing and the partition assembly; the translation drive unit is disposed inside the middle housing.

[0019] The output end of the translation drive unit cooperates with the input end of the translation transmission unit to drive the partition assembly to move horizontally.

[0020] Furthermore, the freeze-drying unit includes a refrigeration system, a vacuum system, and a lower chamber;

[0021] The refrigeration system is located outside the lower chamber and communicates with the interior of the lower chamber, and is used to provide cold energy to the freeze-drying unit;

[0022] The vacuum system is located outside the lower chamber and communicates with the interior of the lower chamber to create a vacuum environment inside the freeze-drying unit.

[0023] Furthermore, the lower housing is equipped with a rotary drive unit and a stirring unit.

[0024] The output end of the rotary drive unit is connected to the stirring unit and drives the stirring unit to rotate;

[0025] The stirring section is made of a flexible and elastically deformable material.

[0026] Furthermore, the freeze-drying unit also includes a flip door; one edge of the flip door is hinged to the edge of the side end face of the lower box, and a sealing ring is provided around the inner end face; a locking mechanism is provided between the flip door and the lower box.

[0027] Furthermore, the combined drying device also includes a control system; the control system includes an integrated setting panel, display screen and PLC, arranged on the outer end face of the upper housing.

[0028] The control system is electrically connected to the refrigeration and drying system, the refrigeration system, the vacuum system, the translation drive unit, and the rotation drive unit;

[0029] The setting panel is used by the operator to set the start-up, stop-up, operating time, cooling temperature, vacuum degree, and start-up and stop of the translation drive and rotation drive of the combined drying unit.

[0030] The display screen is used to display the operating time, cooling temperature, vacuum level, and operating status of the combined drying unit;

[0031] The PLC is used to control the start and stop of the refrigeration and drying system, refrigeration system, vacuum system, translation drive unit and rotary drive unit according to the operator's settings.

[0032] A method of using a rehydrated pre-prepared vegetable low-temperature combined drying device includes:

[0033] S1. Ensure the channel is closed; evenly place the food to be processed into each grid of the shaping section; the liquid level of the food should not exceed two-thirds of the height of the grid;

[0034] S2. Set the operating time, cooling temperature and vacuum level through the setting panel, and start the combined drying device;

[0035] S3. After all the ingredients have been frozen, solidified, and dried into a solid state, the PLC controls the refrigeration and drying system to stop working and controls the translation drive unit to drive the partition assembly to move to the outside of the middle box through the translation transmission unit, and the channel opens.

[0036] S4. Press the ingredients in the grid one by one into the lower box; the PLC controls the translation drive unit to drive the partition assembly to move into the middle box through the translation transmission unit, and the channel is closed;

[0037] S5. The PLC controls the refrigeration system, vacuum system and rotary drive unit to start, and stirs and dehydrates the shaped food while it is being processed.

[0038] S6. After the food ingredients are freeze-dried, the PLC controls the refrigeration system, vacuum system and rotary drive unit to stop; the food ingredients are taken out and packaged to complete the preparation of rehydrated pre-cooked dishes.

[0039] The beneficial effects of this invention are:

[0040] 1. Equipped with a shaping unit, it can perform pretreatment before freeze-drying of food ingredients, pre-dry the food ingredients to remove surface moisture, and freeze them into divisible blocks, which helps to save time and energy during freeze-drying and can shape the food for easy packaging.

[0041] 2. The transfer unit can form a channel inside the combined drying device for transferring food from the shaping unit to the freeze-drying unit, reducing the chance of food coming into contact with the outside world and thus contributing to food hygiene and safety.

[0042] 3. By setting up a freeze-drying unit, ingredients can be dehydrated through vacuuming while being frozen, resulting in dried and packaged pre-made vegetable blocks. This type of rehydrated pre-made food helps maintain the nutrition and taste of the ingredients and reduces transportation and storage costs. Since freeze-drying does not affect fruits and vegetables, it is possible to place fruits and vegetables in the pre-made food, increasing flavor and dietary fiber. Moreover, rehydrated pre-made food can be eaten simply by soaking in water, which is convenient and quick, meeting the food security needs in environments where low-temperature preservation is not possible in the wild. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0044] Figure 1 A schematic diagram of the overall structure of a low-temperature combined drying device for rehydrated pre-cooked vegetables;

[0045] Figure 2 This is a schematic diagram of the internal structure of a low-temperature combined drying device for rehydrated pre-cooked vegetables.

[0046] Figure 3 A schematic diagram of the overall structure of an embodiment of a low-temperature combined drying device for rehydrated pre-prepared vegetables;

[0047] Figure 4 A schematic diagram of the internal structure of an embodiment of a low-temperature combined drying device for rehydrated pre-cooked vegetables;

[0048] Figure 5 A schematic diagram of the overall structure of another embodiment of the low-temperature combined drying device for rehydrated pre-prepared vegetables;

[0049] Figure 6 A schematic diagram of the partition assembly structure of a low-temperature combined drying device for rehydrated pre-cooked vegetables;

[0050] Figure 7 A schematic diagram of the rotary drive unit and stirring unit of a low-temperature combined drying device for rehydrated pre-cooked vegetables;

[0051] In the diagram: 1. Shaping unit; 101. Shaping section; 102. Top cover; 103. Upper housing; 104. Propulsion mechanism; 105. Propulsion block; 106. Propulsion platform; 107. Elastic part; 108. Propulsion drive part; 109. Propulsion transmission part; 110. Housing; 2. Transfer unit; 201. Partition assembly; 202. Slot; 203. Middle housing; 204. Sealing gasket; 205. Translation transmission part; 3. Freeze-drying unit; 301. Lower housing; 302. Rotation drive part; 303. Stirring part; 304. Tilting door; 4. Control system. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] It should be noted that when a component is referred to as "fixed to," "placed," "equipped with," "provided with," "arranged on," or "connected to" another component, it can be directly on the other component or may have an intervening component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or may have an intervening component present.

[0055] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] Please refer to the attached document. Figures 1-7To better understand the specific structure and working principle of this invention, a rehydrated pre-prepared vegetable low-temperature combined drying device is provided, such as... Figure 1 As shown, it includes a shaping unit 1, a transfer unit 2, and a freeze-drying unit 3;

[0057] The shaping unit 1 is disposed on the upper end of the transfer unit 2, and includes a shaping section 101 having a plurality of vertically penetrating grids; the shaping unit 1 is used for low-temperature freezing and drying shaping of food ingredients;

[0058] The freeze-drying unit 3 is located at the lower end of the transfer unit 2 and is used for low-temperature vacuum dehydration of the food.

[0059] The transfer unit 2 is connected at its upper end to the shaping unit 1 and at its lower end to the freeze-drying unit 3. A movable partition assembly 201 is provided in the middle. Figure 2 As shown; the transfer unit 2 is used to form a channel inside the combined drying device for transferring food ingredients from the shaping unit 1 to the freeze-drying unit 3.

[0060] It should be noted that the shaping part 101 preferably consists of several metal plates, such as stainless steel, which are welded or integrally formed to form a grid structure; the number of grids is not limited and can be determined according to the specific needs of implementation; the grid cross-sectional shape can be rectangular or square, and the grid height and cross-sectional shape can be determined according to the shape and size of the rehydrated pre-cooked food product.

[0061] In specific implementation, this invention includes a shaping unit 1, which can pre-treat the ingredients before freeze-drying, initially drying the ingredients to remove surface moisture and freezing them into divisible blocks. This saves time and energy during freeze-drying and facilitates packaging. The invention also includes a transfer unit 2, which forms a channel within the combined drying device for transferring ingredients from the shaping unit 1 to the freeze-drying unit 3, reducing the chance of contact between the ingredients and the outside environment, thus improving food hygiene and safety. The freeze-drying unit 3 allows for simultaneous freezing and vacuum dehydration of the ingredients, resulting in dried, packaged pre-prepared vegetable blocks. These rehydrated pre-prepared vegetables help maintain the nutritional value and taste of the ingredients while reducing transportation and storage costs. Since freeze-drying does not affect fruits and vegetables, they can be added to the pre-prepared vegetables, increasing flavor and dietary fiber. Furthermore, the rehydrated pre-prepared vegetables only require soaking in water before consumption, making them convenient and quick, meeting the food security needs of environments where low-temperature preservation is not possible in the wild.

[0062] In one embodiment provided by the present invention, such as Figure 2 As shown, the shaping unit 1 includes an upper cover 102, an upper box body 103, a refrigeration and drying system, and a shaping part 101;

[0063] The upper cover 102 has one edge hinged to one edge of the upper end face of the upper box 103, and a sealing ring is formed around the lower end face; a locking mechanism is provided between the upper cover 102 and the upper box 103.

[0064] The refrigeration and drying system is located outside the upper housing 103 and communicates with the interior of the upper housing 103, and is used to provide cooling energy and wind energy to the shaping unit 1;

[0065] The shaping part 101 is disposed inside the upper housing 103.

[0066] The refrigeration and drying system includes an exhaust fan installed on the side wall of the upper housing 103.

[0067] It should be noted that the top cover 102 preferably adopts an upward opening method; the locking mechanism between the top cover 102 and the upper box 103 (not shown in the figure) preferably adopts a latch structure, but other commonly used similar structures can also be used, as long as they can lock and unlock the top cover 102 and the upper box 103.

[0068] It should be noted that a sealing ring is made around the lower end face of the upper cover 102. The sealing ring is preferably fixed to the upper cover 102 by adhesive. The sealing ring is preferably made of silicone material, which can effectively seal the gap formed after the upper cover 102 and the upper box 103 are fastened together.

[0069] It should be noted that the refrigeration and drying system can be fixed by adding a separate box to the outside of the upper box 103 and connecting it to the inside of the upper box 103 through pipes.

[0070] It should be noted that the refrigeration and drying system is an existing technology. It uses refrigeration equipment to provide a low-temperature environment and then uses a blower to blow cold air onto the food. This can dry the surface moisture of the food while freezing it, and finally form frozen blocks of food in each grid.

[0071] It should be noted that the shaping part 101 is preferably fixed to the upper box 103 by welding or by a support structure at the bottom of the upper box 103.

[0072] It should be noted that the exhaust device is preferably installed on the through hole opened on the side wall of the upper housing 103, and a one-way check valve is added to discharge the dried water vapor to the outside.

[0073] In practice, the refrigeration and drying system can provide pretreatment for food before freeze-drying and shape the food to facilitate subsequent packaging; freezing the food into ice in advance and air-drying to remove surface moisture helps reduce energy consumption and shorten the time in the freeze-drying process.

[0074] In one implementation, such as Figure 4 , Figure 6 The transfer unit 2 includes a middle box 203 with slots 202 on its side end face; the partition assembly 201 is horizontally movable inside the middle box 203 through the slots 202; the upper and lower end faces of the partition assembly 201 are provided with corresponding sealing gaskets 204 that are in close contact with the lower end face of the shaping part 101 and the upper end face of the freeze-drying unit 3.

[0075] The transfer unit 2 further includes a translation transmission part 205 and a translation drive part; the translation transmission part 205 is disposed between the middle box 203 and the partition assembly 201; the translation drive part is disposed inside the middle box 203;

[0076] The output end of the translation drive unit cooperates with the input end of the translation transmission unit 205 to drive the partition assembly 201 to move horizontally.

[0077] It should be noted that platforms are fixed on both sides inside the middle box 203, and the partition assembly 201 can move with the support of the platforms.

[0078] It should be noted that the sealing gasket 204 is preferably made of silicone material, which can completely seal the channel between the shaping unit 1, the freeze-drying unit 3 and the transfer unit 2, forming a better sealing environment.

[0079] It should be noted that the translation transmission unit 205 is preferably a gear and rack transmission mechanism; the translation drive unit is preferably a stepper motor; the rack is fixed on one or both sides of the partition assembly 201; the gear is fixed to the output shaft of the stepper motor; the stepper motor is fixed on one or both sides of the middle housing 203; the gear meshes with the rack; the stepper motor starts and drives the gear to rotate, thereby driving the rack and partition assembly 201 to move horizontally inside and outside the middle housing 203.

[0080] It should be noted that, in order to prevent the partition assembly 201 from tilting downwards when it is removed from the middle box 203, a horizontal bracket can be fixed to the lower part of the outer side of the slot 202 of the middle box 203 to support the partition assembly 201.

[0081] In practice, the transfer unit 2 can form a channel inside the combined drying device for transferring food ingredients from the shaping unit 1 to the freeze-drying unit 3; this reduces the chance of food ingredients coming into contact with the outside world during preparation and increases food safety.

[0082] In one implementation, such as Figure 3 As shown, the freeze-drying unit 3 includes a refrigeration system, a vacuum system, and a lower chamber 301;

[0083] The refrigeration system is located outside the lower housing 301 and communicates with the interior of the lower housing 301, and is used to provide cold energy to the freeze-drying unit 3;

[0084] The vacuum system is located outside the lower chamber 301 and communicates with the interior of the lower chamber 301 to create a vacuum environment inside the freeze-drying unit 3.

[0085] It should be noted that the refrigeration system preferably uses commonly used refrigeration equipment in existing technologies, which can achieve a refrigeration environment of -30°C.

[0086] It should be noted that the vacuum system preferably uses commonly used vacuum pumping equipment in existing technology. The vacuum system may also include a vacuum gauge installed in the lower chamber 301 to monitor the vacuum level.

[0087] It should be noted that the refrigeration system and vacuum system are preferably installed in a fixed box outside the lower box 301.

[0088] In practice, refrigeration and vacuum systems can achieve low-temperature vacuum drying of food. This method preserves the nutritional components and taste of the food to the greatest extent, extends the shelf life, and facilitates transportation and storage.

[0089] In one embodiment provided by the present invention, such as Figure 7 As shown, the lower housing 301 is provided with a rotary drive unit 302 and a stirring unit 303.

[0090] The output end of the rotary drive unit 302 is connected to the stirring unit 303 and drives the stirring unit 303 to rotate;

[0091] The stirring section 303 is made of a flexible and elastically deformable material.

[0092] It should be noted that the rotary drive unit 302 is preferably a stepper motor; the stirring unit 303 is preferably a fan blade structure; the output shaft of the stepper motor is connected to the drive shaft of the fan blade and drives the fan blade to rotate.

[0093] It should be noted that the stirring part 303 is made of a flexible and elastically deformable material, preferably rubber or silicone, which can prevent the food pieces from being crushed during the stirring process.

[0094] In practice, a stirring unit 303 is installed in the lower chamber 301, which can ensure that the shaped food ingredients are in full contact with the environment on all surfaces during the freeze-drying process, which helps to speed up the drying process and save time and energy.

[0095] In one implementation, such as Figure 4 As shown, the freeze-drying unit 3 also includes a flip door 304; one edge of the flip door 304 is hinged to the side end edge of the lower box 301, and a sealing ring is provided around the inner end edge; a locking mechanism is provided between the flip door 304 and the lower box 301.

[0096] It should be noted that the sealing ring is preferably made of silicone material; and the sealing ring is preferably fixed to the four edges of the flip door 304 by adhesive.

[0097] It should be noted that the locking mechanism (not shown in the figure) preferably adopts a latch structure, but other commonly used similar structures can also be used, as long as they can lock and unlock the flip door 304 and the lower box 301.

[0098] In one embodiment of the present invention, the combined drying device further includes a control system 4; the control system 4 includes an integrated setting panel, a display screen and a PLC, and is arranged on the outer end face of the upper housing 103.

[0099] The control system 4 is electrically connected to the refrigeration and drying system, the refrigeration system, the vacuum system, the translation drive unit, and the rotation drive unit 302;

[0100] The setting panel is used by the operator to set the start-up, shutdown, operating time, cooling temperature, vacuum degree, and start-up and shutdown of the translation drive unit and the rotary drive unit 302 of the combined drying device;

[0101] The display screen is used to display the operating time, cooling temperature, vacuum level, and operating status of the combined drying unit;

[0102] The PLC is used to control the start and stop of the refrigeration and drying system, refrigeration system, vacuum system, translation drive unit and rotary drive unit 302 according to the operator's settings.

[0103] It should be noted that the control system 4 is embedded in the front side wall of the upper housing 103; the PLC (Programmable Logic Controller) can be a circuit including at least one processor, or a circuit including at least one microcontroller, or a combination of multiple circuits or chips, as long as it can achieve the corresponding function; it is understandable that for those skilled in the art, the control circuit can also be a common circuit composed of amplifiers, comparators, transistors, MOSFETs, etc., to achieve the corresponding function in a purely hardware manner.

[0104] In practice, the control system 4 can realize the automated control of the combined drying device, which is beneficial to the preparation of rehydrated pre-cooked vegetables.

[0105] In one embodiment, such as Figure 3 , Figure 4As shown, the shaping unit 1 can be equipped with a propulsion mechanism 104. The propulsion mechanism 104 is mounted on the upper cover 102, preferably by means of an opening in the upper cover 102, and can move up and down relative to the upper cover 102. It includes propulsion blocks 105, a propulsion platform 106, and an elastic part 107, which are equal in number and shape to the grid. The upper end of each propulsion block 105 is fixedly connected to the propulsion platform 106, which can be fixed by welding. The elastic part 107 is preferably a helical cylindrical spring structure, which is fixed between the propulsion platform 106 and the upper cover 102, and plays the role of returning the propulsion unit to its original position.

[0106] It should be noted that after the shaping unit 1 completes the food pretreatment, it can press down the push platform 106 and push the shaped food in each grid to the freeze-drying unit 3 through the push block 105; the push platform 106 and the push block 105 return to the initial position under the action of the elastic part 107.

[0107] In one embodiment, such as Figure 5 As shown, the propulsion mechanism 104 can be equipped with a propulsion drive unit 108 and a propulsion transmission unit 109; the propulsion transmission unit 109 is disposed between the upper cover 102 and the propulsion platform 106; the propulsion drive unit 108 is disposed on the propulsion platform 106, and its output end cooperates with the input end of the propulsion transmission unit 109.

[0108] It should be noted that the propulsion drive unit 108 is preferably a stepper motor; the propulsion transmission unit 109 is preferably a gear and rack and bevel gear transmission mechanism; the rack is welded or threaded to both sides of the upper cover 102 at its lower end, and passes through the through hole of the propulsion platform 106 in the middle, extending to the upper end of the propulsion platform 106, so that the propulsion platform 106 can move up and down relative to the rack; the two racks are connected by a connecting shaft, and gears that mesh with the racks are welded to both sides of the connecting shaft; a first bevel gear is welded or keyed to the middle of the connecting shaft; the connecting shaft, gears, and bevel gear are all installed in the housing 110 for protection; the propulsion drive unit 108 is fixed on the housing 110, and a second bevel gear is fixed to the output shaft, which is electrically connected to the control system 4; the second bevel gear passes through the hole opened in the housing 110 and meshes with the first bevel gear.

[0109] After the shaping unit 1 completes the pre-processing of the ingredients, the propulsion drive unit 108 can be started by the PLC control; the second bevel gear drives the first bevel gear to rotate and transmits power to both sides, and changes 90°; the gears on both sides mesh with the racks on both sides, driving the propulsion mechanism 104 to move down as a whole, and the shaping ingredients in each grid are pushed to the freeze-drying unit 3 through the propulsion block 105; the PLC controls the propulsion drive unit 108 to reverse, and the propulsion platform 106 and the propulsion block 105 return to the initial position.

[0110] In practice, the propulsion mechanism 104 can replace manual pressing of the ingredients in the grid, saving time and eliminating the need to open the top cover 102, further ensuring food hygiene and safety. The addition of the propulsion drive unit 108 and the propulsion transmission unit 109 can achieve automated control, save manpower, and optimize the preparation process.

[0111] In one embodiment, the lower housing 301 is equipped with a temperature sensor, a vacuum pressure sensor, a speed sensor, and a moisture sensor, all electrically connected to the PLC, which are used to acquire in real time the temperature value, vacuum value, speed value of the stirring part 303, and dryness value of the food in the lower housing 301.

[0112] The PLC acquires the temperature, vacuum, rotational speed, and dryness values. It then processes these values ​​using a dynamic programming energy control model to minimize the temperature, vacuum, rotational speed, and dryness changes under a minimum objective function. By controlling the operation of the refrigeration system, vacuum system, and rotary drive, it continuously adjusts the temperature (T), vacuum (P), and rotational speed (v). stir This is to ensure that the current dryness value reaches the target dryness value; the expression of the dynamic programming energy consumption control model is:

[0113]

[0114] Where: J is the objective function; N is the number of steps; e(i) is the error value. η target For the target dryness value, The first predicted dryness value is when i = 1. The dryness value measured by the moisture sensor; λ1, λ2, and λ3 are weighting coefficients; ΔT, ΔP, and Δv stir The corresponding values ​​are temperature change, vacuum change, and rotation speed change.

[0115] The constraints of the dynamic programming energy consumption control model are:

[0116] T min ≤T≤T max ,P min ≤P≤P max ,

[0117] T min For the minimum temperature, T max For the maximum temperature, P min Minimum vacuum level, P max

[0118] For the maximum vacuum degree, Minimum rotational speed This represents the maximum rotational speed.

[0119] It should be noted that the dynamic programming energy consumption control model can be applied to the energy consumption control of freeze-drying different foods. By continuously adjusting the temperature, vacuum, and rotation speed, the internal environment of the lower chamber can be kept in an optimized state in real time, thereby achieving the lowest energy consumption.

[0120] It should be noted that the constraint on temperature T can prevent the material from melting (too high a temperature) or freezing incompletely (too low a temperature); the constraint on pressure P can ensure that the vacuum level is sufficient to maintain sublimation and desorption (two important stages in the freeze-drying process; during the sublimation stage, the dryness degree of the food η < 0.8, and during the desorption stage, the dryness degree of the food η ≥ 0.8), while avoiding excessive vacuuming and increased energy consumption; the stirring speed v of 303 is also important. stir The constraints prevent material breakage or uneven mixing from causing uneven heating of the food; N is the number of steps, which can be understood as the prediction time domain. Optionally, N=5, which means predicting the dryness of the next 5 control cycles (each cycle can be set to 30 seconds, or it can be understood as the sampling cycle); the weighting coefficients λ1, λ2 and λ3 are preferably obtained through experimental testing. The corresponding values ​​in this system are 0.8, 0.8 and 0.5.

[0121] In one embodiment, the PLC acquires the temperature change value, vacuum degree change value, and rotation speed change value, and calculates the dryness change value of the food using a drying kinetic model. The expression for the drying kinetic model when the moisture in the food is in the sublimation stage is as follows:

[0122]

[0123] The expression for the drying kinetics model when the moisture in the food is in the desorption stage is as follows:

[0124]

[0125] Where: η is the dryness value; k1 is the mass transfer coefficient; k2 is the bound water desorption coefficient; T opt The optimal desorption temperature; T max and T min The corresponding values ​​are the maximum and minimum allowable temperatures; P min The minimum allowable vacuum value; the PLC acquires the dryness change value and obtains the second predicted dryness value η at time t. next The expression is:

[0126]

[0127] The PLC acquires the second predicted dryness value and processes it to obtain the total error value e. total (i), the expression is: etotal (i)=e(i)+δ(η target -η next ), where δ is the weighting coefficient;

[0128] The PLC obtains the total error value and uses the dynamic programming energy consumption control model to obtain the corrected temperature change value, vacuum degree change value, and speed change value, expressed as:

[0129]

[0130] It should be noted that, The drying rate; the optimal desorption temperature T. opt The temperature is 1.1 to 1.2 times the glass transition temperature of the food, and -25℃ is preferred in this system; the mass transfer coefficient k1 is related to the porosity of the material, and 0.05 is preferred in this system; the bound water desorption coefficient k2 is related to the energy barrier for bound water molecules to detach from the surface or internal structure of the material, and 0.005 is preferred in this system; the food undergoes a sublimation stage and a desorption stage during freeze-drying, and the dryness values ​​of the two stages are η<0.8 and η≥0.8 respectively; during the control process, the drying rate calculation formulas of the two states can be switched according to the collected dryness values.

[0131] It should be noted that the dynamic programming energy consumption control model is a feedforward-feedback control strategy based on a dynamic model, which achieves the control objective through rolling optimization and feedback correction; its core steps are as follows:

[0132] Predictive Model: Utilizes a drying kinetics model to predict changes in aridity over a future period (prediction time domain);

[0133] Objective function: Minimize the deviation between the predicted dryness and the target value, while limiting the energy consumption of parameter adjustment.

[0134] Rolling optimization: The optimal parameters are recalculated in each control cycle, executing only the first step of the control instruction. This process is iterated repeatedly; that is, within each sampling period t, the objective function is resolved based on the current state to obtain the optimal control sequence {T(t), P(t), v}. stir (t)}, but only the control quantity of the first step is executed, and the subsequent steps are recalculated in the next cycle.

[0135] In one embodiment, the PLC uses a concrete logic algorithm to compensate and adjust the temperature value T and vacuum value P output by the dynamic programming energy consumption control model when the drying device is under nonlinear response and external disturbance conditions; the concrete logic algorithm includes:

[0136] To visualize this, we can use the dryness deviation Δη and the rate of change of dryness deviation. Converted into a set of linguistic values ​​for dryness deviation: {"negative large", "negative small", "zero", "positive small", "positive large"}, and linguistic values ​​for dryness change rate: {"rapid decrease", "slow decrease", "unchanged", "slow increase", "rapid increase"};

[0137] The concrete rule base, based on expert experience, performs logical judgments to combine the linguistic values ​​of dryness deviation and dryness change rate, and transforms them into a pre-adjusted temperature correction value δT stored in the concrete rule base. i and pre-adjusted vacuum correction value δP j Form a triggering rule, where i and j are both positive integers ≥ 1;

[0138] By refining the solution, when the drying device reaches the trigger rule condition, the final temperature correction value δT and vacuum correction value δP are obtained using the discrete centroid method.

[0139] It should be noted that, Based on the set of linguistic values ​​and expert experience, 20 pre-adjusted temperature correction values ​​δT can be obtained. i and 20 pre-adjusted vacuum correction values ​​δP j This forms a concrete rule base; the discrete centroid method is a conventional algorithm, and the selection of rule trigger degree can be judged based on expert experience.

[0140] In its specific implementation, this invention combines a dynamic programming energy consumption control model with a concrete logic algorithm. The dynamic programming energy consumption control model acts as the main controller, providing global optimization parameters (T, P, vstir). The concrete logic algorithm, acting as a compensator, fine-tunes the output of the dynamic programming energy consumption control model to obtain (δT, δP), forming a dynamic priority: for example, when the dryness deviation is large (e.g., Δη>10%), the correction amount of the concrete logic algorithm dominates; when approaching the target value (e.g., Δη<2%), the optimization weight of the dynamic programming energy consumption control model is higher. This achieves the accuracy and robustness of the drying process. The dynamic programming energy consumption control model ensures efficient approximation of the target within the model's prediction range, while the concrete logic algorithm dynamically responds to uncertainties and nonlinear disturbances in actual production. The synergy between the two significantly improves the control performance of the freeze-drying unit.

[0141] Furthermore, the relationship between the dynamic programming energy consumption control model and the drying kinetics model is embodied as a closed-loop system of prediction, optimization, and dynamic adjustment: the drying kinetics model provides the theoretical framework for the drying process, serves as the basis for prediction and optimization by the dynamic programming energy consumption control model, and predicts the next step of the dryness degree change pattern through the kinetics model, thus obtaining the predicted dryness degree value for the next step; the predicted dryness degree value is weighted and calculated with the actual measured dryness degree value to obtain the overall dryness degree error; this allows for more precise control of the system's operation; the dynamic programming energy consumption control model optimizes the control input in real time and uses the predicted value provided by the drying kinetics model to correct the total error, so that the system can adapt to actual production conditions. Uncertainty in production; the synergy between the two achieves high efficiency (shortening time and reducing energy consumption) and robustness (coping with disturbances and parameter changes) in the drying process; by reasonably simplifying the model, designing adaptive strategies and optimizing the time domain selection, the drying kinetic model can play an important role in complex drying scenarios; through practical testing: the overall drying time of ingredients can be reduced by 15% to 20%; the total energy consumption is reduced by about 25%; and by synergistic control of stirring speed and vacuum degree, local overheating or undried areas of ingredients are reduced; through model predictive control and concrete logic compensation, the freeze-drying process can be accurately and dynamically optimized, taking into account both drying efficiency and energy consumption, which can significantly improve the quality and production economy of rehydrated pre-prepared dishes.

[0142] A method of using a rehydrated pre-prepared vegetable low-temperature combined drying device includes:

[0143] S1. Ensure the channel is closed; evenly place the food to be processed into each grid of the shaping section 101; the liquid level of the food should not exceed two-thirds of the height of the grid.

[0144] S2. Set the operating time, cooling temperature and vacuum level through the setting panel, and start the combined drying device;

[0145] S3. After all the ingredients are frozen, condensed, and dried into a solid state, the PLC controls the refrigeration and drying system to stop working and controls the translation drive unit to drive the partition assembly 201 to move to the outside of the middle box 203 through the translation transmission unit 205, and the channel opens.

[0146] S4. Press the ingredients in the grid one by one into the lower box 301; the PLC controls the translation drive unit to drive the partition assembly 201 to move into the middle box 203 through the translation transmission unit 205, and the channel is closed;

[0147] S5. The PLC controls the refrigeration system, vacuum system and rotary drive unit 302 to start, and stir and dehydrate the shaped food while it is being processed.

[0148] S6. After the food ingredients are freeze-dried, the PLC controls the refrigeration system, vacuum system and rotary drive unit 302 to stop; the food ingredients are taken out and packaged to complete the preparation of rehydrated pre-cooked dishes.

[0149] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0150] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-temperature combined drying device for rehydrated pre-prepared vegetables, characterized in that, It includes a shaping unit, a transfer unit, a freeze-drying unit, and a control system; The shaping unit is located at the upper end of the transfer unit and includes a shaping section with several vertically penetrating grids; the shaping unit is used for low-temperature freezing and drying shaping of food ingredients; The shaping unit includes an upper housing and a refrigeration and drying system; The refrigeration and drying system is located outside the upper chamber and communicates with the interior of the upper chamber, and is used to provide cold energy and wind energy to the shaping unit. The transfer unit is connected to the shaping unit at its upper end and to the freeze-drying unit at its lower end, and a movable partition assembly is provided in the middle; the transfer unit is used to form a channel inside the combined drying device for transferring food from the shaping unit to the freeze-drying unit. The freeze-drying unit is located at the lower end of the transfer unit and is used for low-temperature vacuum dehydration of the food. The freeze-drying unit includes a refrigeration system, a vacuum system, and a lower chamber; The refrigeration system is located outside the lower chamber and communicates with the interior of the lower chamber, and is used to provide cold energy to the freeze-drying unit; The vacuum system is located outside the lower chamber and communicates with the interior of the lower chamber to create a vacuum environment inside the freeze-drying unit. The lower chamber is equipped with a rotary drive unit and a stirring unit. The output end of the rotary drive unit is connected to the stirring unit and drives the stirring unit to rotate; The stirring section is made of a flexible and elastically deformable material; The control system includes a PLC; the PLC is used to control the start and stop of the refrigeration drying system, refrigeration system, vacuum system and rotary drive unit according to the operator's settings. The lower chamber is equipped with a temperature sensor, a vacuum pressure sensor, a speed sensor, and a moisture sensor, all of which are electrically connected to the PLC. These sensors are used to acquire the temperature value, vacuum value, speed value of the stirring section, and dryness value of the food in the lower chamber in real time. The PLC acquires the temperature, vacuum, rotational speed, and dryness values. It then processes these values ​​using a dynamic programming energy control model to minimize the temperature, vacuum, rotational speed, and dryness changes under a minimum objective function. The PLC continuously adjusts the temperature value by controlling the operation of the refrigeration system, vacuum system, and rotary drive unit. Vacuum degree value and speed value This is to ensure that the current dryness value reaches the target dryness value; the expression of the dynamic programming energy consumption control model is: ； in: The objective function is... Number of steps; , For the target dryness value, The first predicted dryness value, when i=1 hour The dryness value measured by the moisture sensor; , and These are the weighting coefficients; , and The corresponding values ​​are temperature change, vacuum change, and rotation speed change. The constraints of the dynamic programming energy consumption control model are: ； Minimum temperature For the maximum temperature, Minimum vacuum level For the maximum vacuum degree, Minimum rotational speed This represents the maximum rotational speed.

2. The rehydrated pre-prepared vegetable low-temperature combined drying device according to claim 1, characterized in that, The shaping unit also includes a top cover; The upper cover has one edge hinged to one edge of the upper end face of the upper box body, and a sealing ring is formed around the four edges of the lower end face; a locking mechanism is provided between the upper cover and the upper box body; The shaping part is located inside the upper housing.

3. The rehydrated pre-prepared vegetable low-temperature combined drying device according to claim 2, characterized in that, The refrigeration and drying system includes an exhaust fan installed on the side wall of the upper chamber.

4. The rehydrated pre-prepared vegetable low-temperature combined drying device according to claim 3, characterized in that, The transfer unit includes a middle box with slots on its side end face; the partition assembly is horizontally movable inside the middle box through the slots; the upper and lower end faces of the partition assembly are provided with corresponding sealing gaskets that fit tightly against the lower end face of the shaping part and the upper end face of the freeze-drying unit.

5. The rehydrated pre-prepared vegetable low-temperature combined drying device according to claim 4, characterized in that, The transfer unit further includes a translation transmission unit and a translation drive unit; the translation transmission unit is disposed between the middle housing and the partition assembly; the translation drive unit is disposed inside the middle housing; The output end of the translation drive unit cooperates with the input end of the translation transmission unit to drive the partition assembly to move horizontally.

6. The rehydrated pre-processed vegetable low-temperature combined drying device according to claim 1, characterized in that, The freeze-drying unit also includes a flip door; one edge of the flip door is hinged to the edge of the side end face of the lower box, and a sealing ring is provided around the inner end face; a locking mechanism is provided between the flip door and the lower box.

7. The rehydrated pre-prepared vegetable low-temperature combined drying device according to claim 5, characterized in that, The control system also includes an integrated setting panel and display screen, which are arranged on the outer end face of the upper housing; The control system is electrically connected to the refrigeration and drying system, the refrigeration system, the vacuum system, the translation drive unit, and the rotation drive unit; The setting panel is used by the operator to set the start-up, stop-up, operating time, cooling temperature, vacuum degree, and start-up and stop of the translation drive and rotation drive of the combined drying unit. The display screen is used to display the operating time, cooling temperature, vacuum level, and operating status of the combined drying unit; The PLC is used to control the start and stop of the translation drive unit according to the operator's settings.

8. A method of using a rehydrated pre-prepared vegetable low-temperature combined drying device, applied to the rehydrated pre-prepared vegetable low-temperature combined drying device as described in claim 7, characterized in that, include: S1. Ensure the channel is closed; evenly place the food to be processed into each grid of the shaping section; the liquid level of the food should not exceed two-thirds of the height of the grid; S2. Set the operating time, cooling temperature and vacuum level through the setting panel, and start the combined drying device; S3. After all the ingredients have been frozen, solidified, and dried into a solid state, the PLC controls the refrigeration and drying system to stop working and controls the translation drive unit to drive the partition assembly to move to the outside of the middle box through the translation transmission unit, and the channel opens. S4. Press the ingredients in the grid one by one into the lower box; the PLC controls the translation drive unit to drive the partition assembly to move into the middle box through the translation transmission unit, and the channel is closed; S5. The PLC controls the refrigeration system, vacuum system and rotary drive unit to start, and stirs and dehydrates the shaped food while it is being processed. S6. After the food ingredients are freeze-dried, the PLC controls the refrigeration system, vacuum system and rotary drive unit to stop; the food ingredients are taken out and packaged to complete the preparation of rehydrated pre-cooked dishes.

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