Magnetic control low-temperature freeze drying equipment applied to agricultural product processing

Abstract

The invention discloses magnetic control low-temperature freeze-drying equipment applied to agricultural product processing, and relates to the technical field of low-temperature freeze-drying processing equipment.The magnetic control low-temperature freeze-drying equipment comprises an intelligent magnetic field monitoring device, a freeze-drying cooling device, an intelligent heating device, a vacuumizing device and a controller; the intelligent magnetic field monitoring device is used for carrying out magnetic field intensity control and detection on the rapidly cooled food, the freeze-drying cooling device is arranged outside the freeze-drying cavity and is used for refrigerating and cooling the freeze-drying cavity, the intelligent heating device is used for heating and sublimating frozen agricultural products, and the vacuumizing device is used for carrying out vacuumizing treatment on the freeze-drying cavity; the intelligent magnetic field monitoring device comprises a plurality of magnetic field rings with the same axial magnetic field intensity, a magnetic control power controller and a magnetic field intensity monitor; the magnetic control power controller is used for controlling the magnetic field intensity of the magnetic field ring group; the size of ice crystals in the food in the freeze-drying process is regulated and controlled through the magnetic field, so that preparation is made for the later sublimation stage, and it is guaranteed that energy consumption and nutrient loss are minimum in the sublimation process.

Description

Technical Field

[0001] The invention relates to the technical field of low-temperature freeze-drying processing equipment, and in particular to a magnetically controlled low-temperature freeze-drying device used for processing agricultural products. Background Art

[0002] The vacuum freeze dryer is called a freeze dryer, which originated from the vacuum freeze drying technology in the 1920s. The vacuum freeze drying technology is to first freeze the wet material or solution to be freeze-dried into a solid state at a relatively low temperature (such as 0℃~-50℃), and then sublimate the water in the solid state directly into a gaseous state without passing through the liquid state under vacuum, and finally achieve the drying technology of dehydrating the material or solution. It is mainly used in medicines, foods, health products, cosmetics and other products with high heat sensitivity.

[0003] The freeze dryer mainly processes the corresponding food products through freeze drying, and there are three stages: pre-freezing, vacuum sublimation drying, and analytical drying. Among them, pre-freezing is the first stage of freeze-dried food products, and it is also a more important stage. In order to ensure the effect of pre-freezing, in the industrial production process, food products are pre-frozen by freeze dryers, or pre-freezing using pre-quick freezing technology, such as liquid nitrogen, rapid pre-cooling machines, etc., which increases the operating costs of the enterprise and also increases energy consumption. Some foods even require secondary freezing and quick freezing. The refrigeration system of the current existing freeze dryers, whether it is the refrigeration system of the freeze dryer for production or the refrigeration system of the freeze dryer for scientific research, cannot provide a quick freezing mode, and is often pre-cooled in other forms, resulting in a waste of resources.

[0004] The pre-freezing device in the first stage of the freeze dryer is mainly used to freeze the water in the food to form ice crystals, which are then sublimated in a low temperature and low pressure environment. The faster the pre-freezing speed, the smaller the ice crystal size, so that the energy consumption and nutrient loss during the sublimation process are minimized. However, the current freeze dryers do not have the function of adjusting the size of ice crystals.

[0005] Therefore, providing a freeze-drying device that can regulate the size of ice crystals during the freeze-drying process is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] The purpose of the present invention is to provide a magnetically controlled low-temperature freeze-drying device for use in agricultural product processing to solve the problems existing in the above-mentioned prior art. The size of ice crystals inside the food during the freeze-drying process is regulated by magnetic field control, thereby preparing for the subsequent sublimation stage and ensuring that energy consumption and nutrient loss during the sublimation process are minimized.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The present invention provides a magnetically controlled low-temperature freeze-drying device for processing agricultural products, comprising an intelligent magnetic field monitoring device, a freeze-drying cooling device, an intelligent heating device, a vacuuming device and a controller; the intelligent magnetic field monitoring device is used to control and detect the magnetic field strength of foods that are rapidly cooled, the freeze-drying cooling device is arranged outside a freeze-drying chamber for cooling and cooling the freeze-drying chamber, the intelligent heating device is arranged in the freeze-drying chamber for heating and sublimating the frozen agricultural products, the vacuuming device is used to vacuum the freeze-drying chamber, and the controller is used to control the operation of the entire device; wherein the intelligent magnetic field monitoring device comprises a plurality of magnetic field rings with the same axial magnetic field strength, a magnetically controlled power controller and a magnetic field strength monitor, the plurality of magnetic field rings are sequentially connected to form a magnetic field ring group, the magnetically controlled power controller is used to control the magnetic field strength of the magnetic field ring group, and the magnetic field strength monitor is used to monitor the magnetic field strength of the magnetic field ring group.

[0009] Preferably, it further comprises a frame, and the intelligent magnetic field monitoring device, freeze-drying cooling device, intelligent heating device, vacuum device and controller are all arranged on the frame.

[0010] Preferably, the frame is a rectangular box structure formed by welding a plurality of plate structures.

[0011] Preferably, the intelligent magnetic field monitoring device is arranged on one side of the top of the frame, wherein the magnetic field monitoring control panel of the intelligent magnetic field monitoring device is installed on the outside of the frame, the control knob of the magnetic control power controller and the monitoring screen of the magnetic field strength monitor are arranged on the magnetic field monitoring control panel, and the magnetic field ring group includes 4 independent magnetic field rings, and the 4 magnetic field rings are evenly distributed in a cylindrical cavity along the axial direction, and two adjacent magnetic field rings are connected by bolts.

[0012] Preferably, the magnetic field ring is a circular magnetic field ring composed of multiple turns of Helmholtz coils. The magnetic field ring combines the Biot-Savart law and performs magnetic field simulation of the coil through COMSOL simulation software to determine the coil size and its placement position in the cylindrical cavity.

[0013] Preferably, the freeze-drying and cooling device includes a freeze-drying chamber, a compressor, a condenser, an evaporator, a capillary tube and a heat exchanger arranged inside the frame. The evaporator is wrapped on the outer wall of the freeze-drying chamber, and the compressor provides power for the entire freeze-drying and cooling device. The compressor extracts gaseous refrigerant from the evaporator, passes through the heat exchanger and presses it into the condenser. The gaseous refrigerant forms high-pressure and high-temperature gas in the compressor. The high-pressure gaseous refrigerant is liquefied when passing through the condenser to form a low-temperature and high-pressure condensing agent, and the refrigerant is depressurized through the capillary tube, thereby re-entering the evaporator through the heat exchanger. The evaporator is coiled outside the freeze-drying chamber, and the energy is taken away by the inside of the freeze-drying chamber. The refrigerant forms gas, and the gaseous refrigerant is extracted by the compressor and pumped into the condenser. In this way, the refrigerant is circulated in a closed manner to continuously cool and cool the freeze-drying chamber.

[0014] Preferably, the intelligent heating device is arranged in the freeze-drying chamber, and the intelligent heating device includes a heating material rack, an electric heating wire heating plate and a PID controller; the heating material rack includes multiple layers of material plates arranged at intervals up and down, and the electric heating wire heating plate is arranged under each layer of material plates, and each electric heating wire heating plate is provided with a separate PID controller, and the temperature is increased in stages and sections through the intelligent temperature control program of the PID controller, thereby completing the sublimation process of the material.

[0015] Preferably, the heating material rack is made of aluminum or copper, and includes 5 layers of material plates, and the heating wire heating plate is fixed under each layer of the material plate by screws.

[0016] Preferably, the vacuum pump comprises a rotary vane vacuum pump and a stainless steel pipe, the rotary vane vacuum pump is connected to the freeze-drying chamber via the stainless steel pipe, the rotary vane vacuum pump is fixed to the frame via bolts, and the air outlet of the rotary vane vacuum pump has a reserved interface for an external pipe to facilitate the discharge of gas.

[0017] Preferably, the controller includes a touch screen and a PLC control board, the touch screen is arranged on the outside of the frame, and the PLC control board is arranged on the inside of the frame. The controller can intelligently set various stage parameters including cooling time, cooling temperature, magnetic field strength, magnetic field time, heating temperature, time and cavity vacuum pressure according to different agricultural product matrix characteristics.

[0018] Compared with the prior art, the present invention has achieved the following technical effects:

[0019] The magnetically controlled low-temperature freeze-drying equipment used for agricultural product processing in the present invention is the first to use a magnetic field monitoring method in a freeze dryer, and regulates the state of ice crystals inside the product during the rapid cooling process, and regulates the size of ice crystals inside the food during the freeze-drying process, thereby preparing for the subsequent sublimation stage, and ensuring that energy consumption and nutrient loss are minimized during the sublimation process;

[0020] Furthermore, high-performance simulation software is used to simulate the uniformity of the magnetic field in the circular cavity to ensure the uniformity of the magnetic field strength;

[0021] Furthermore, according to the product matrix characteristics, the parameters of each processing stage are intelligently controlled, and the entire processing process is completed in "one-click automatic", which improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of the magnetically controlled low-temperature freeze-drying equipment used in agricultural product processing in the present invention;

[0024] Figure 2 It is a structural schematic diagram of the magnetic field ring group in the present invention;

[0025] Figure 3 This is a simulation diagram of magnetic field density in the present invention;

[0026] Figure 4 It is a structural schematic diagram of the intelligent heating device in the present invention;

[0027] In the figure: 1. Intelligent magnetic field monitoring device; 11. Magnetic field ring; 12. Magnetron power controller; 13. Magnetic field strength monitor; 14. Bolt; 15. Cylindrical cavity; 2. Freeze-drying cooling device; 3. Intelligent heating device; 31. Heating material rack; 32. Heating wire heating plate; 33. PID controller; 4. Vacuum extraction device; 5. Controller; 6. Freeze-drying chamber; 7. Rack; 8. Compressor; 9. Evaporator. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The purpose of the present invention is to provide a magnetically controlled low-temperature freeze-drying device for use in agricultural product processing to solve the problems existing in the prior art.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] The magnetically controlled low-temperature freeze-drying equipment used in agricultural product processing in this embodiment is as follows: Figure 1-Figure 4 As shown, it includes an intelligent magnetic field monitoring device 1, a freeze-drying cooling device 2, an intelligent heating device 3, a vacuum device 4 and a controller 5; the intelligent magnetic field monitoring device 1 is used to control and detect the magnetic field strength of foods that are cooled rapidly, the freeze-drying cooling device 2 is arranged outside the freeze-drying chamber 6 for refrigerating and cooling the freeze-drying chamber 6, the intelligent heating device 3 is arranged in the freeze-drying chamber 6, and is used to heat and sublimate the frozen agricultural products, the vacuum device 4 is used to vacuum the freeze-drying chamber 6, and the controller 5 is used to control the operation of the entire equipment; wherein, the intelligent magnetic field monitoring device 1 includes a plurality of magnetic field rings 11 with the same axial magnetic field strength, a magnetically controlled power controller 12 and a magnetic field strength monitor 13, the plurality of magnetic field rings 11 are connected in sequence to form a magnetic field ring group, the magnetically controlled power controller 12 is used to control the magnetic field strength of the magnetic field ring group, and the magnetic field strength monitor 13 is used to monitor the magnetic field strength of the magnetic field ring group.

[0032] In this specific embodiment, a frame 7 is also included, on which the intelligent magnetic field monitoring device 1, the freeze-drying cooling device 2, the intelligent heating device 3, the vacuum device and the controller 5 are all arranged; the frame 7 is a rectangular box structure formed by welding multiple plate structures.

[0033] In this specific embodiment, the intelligent magnetic field monitoring device 1 is arranged on one side of the top of the frame 7, wherein the magnetic field monitoring control panel of the intelligent magnetic field monitoring device 1 is installed on the outside of the frame 7, the control knob of the magnetic control power controller 12 and the monitoring screen of the magnetic field strength monitor 13 are arranged on the magnetic field monitoring control panel, and the magnetic field ring group includes 4 independent magnetic field rings 11, and the 4 magnetic field rings 11 are evenly distributed in a cylindrical cavity 15 along the axial direction, and two adjacent magnetic field rings 11 are connected by bolts 14. The material of the cylindrical cavity 15 is 304 stainless steel paper, and a single magnetic field ring 11 is composed of a magnetic coil and an epoxy resin mounting sheet.

[0034] In this specific embodiment, the magnetic field ring 11 is a circular magnetic field ring composed of multiple turns of Helmholtz coils. The magnetic field ring 11 combines the Biot-Savart law and uses COMSOL simulation software to simulate the magnetic field of the coil, thereby determining the size of the coil and its placement in the cylindrical cavity. The magnetic field strength of the entire magnetic field ring 11 is consistent in the axial direction. The magnetic field power controller 5 controls the magnetic field strength of the entire magnetic field ring 11, and the strength is infinitely adjustable between 10 and 20 mT. According to the characteristics of the material matrix, during the rapid cooling and freezing process, an intelligent magnetic field monitoring device 1 is used to detect and control the cooling magnetic field of the agricultural products to ensure precise control of the ice crystal state inside the agricultural products during the rapid cooling process. When prefabricating the magnetic field ring 11, the Helmholtz coil is first theoretically calculated, and based on the Biot-Savart theorem, the magnetic field strength and distribution of any point in the single-turn or multi-turn Helmholtz coil are simulated and analyzed, such as Figure 3 As shown in the simulation diagram, it can be seen that the magnetic field strength and uniformity are consistent between the two Helmholtz coils, and the distance between the coils is the radius of the coil, thereby ensuring the uniformity of the magnetic field density between the two coils. The magnetic field density and uniformity between the coils are simulated using high-performance simulation software, but it is not limited to circular coils. Square coils and heterosexual coils can be used as long as the magnetic field strength and uniformity inside the coils are consistent.

[0035] In this specific embodiment, the freeze-drying cooling device 2 includes a freeze-drying chamber 6, a compressor 8, a condenser, an evaporator 9, a capillary tube and a heat exchanger arranged inside a frame 7. The evaporator 9 is wrapped on the outer wall of the freeze-drying chamber 6. The compressor 8 provides power for the entire freeze-drying cooling device 2. The compressor 8 extracts the gaseous refrigerant from the evaporator 9, passes through the heat exchanger and presses it into the condenser. The gaseous refrigerant forms a high-pressure and high-temperature gas in the compressor 8. The high-pressure gaseous refrigerant liquefies when passing through the condenser to form a low-temperature and high-pressure condensing agent, and the refrigerant is depressurized through the capillary tube, thereby re-entering the evaporator 9 through the heat exchanger. The evaporator 9 is coiled around the outside of the freeze-drying chamber 6, and the energy is taken away by the inside of the freeze-drying chamber 6. The refrigerant forms a gas, and the gaseous refrigerant is extracted by the compressor 8 and pumped into the condenser. In this way, the refrigerant is circulated in a closed manner to continuously cool and cool the freeze-drying chamber 6.

[0036] In this specific embodiment, the intelligent heating device 3 is arranged in the freeze-drying chamber 6, and the intelligent heating device 3 includes a heating material rack 31, an electric heating wire heating plate 32 and a PID controller 33; the heating material rack 31 includes a plurality of material plates arranged at intervals up and down, and an electric heating wire heating plate 32 is arranged under each layer of material plates. Each electric heating wire heating plate 32 is provided with a separate PID controller 33, and the intelligent temperature control program of the PID controller 33 is used to perform graded and segmented heating, thereby completing the sublimation process of the material.

[0037] In this specific embodiment, the heating material rack 31 is made of aluminum or copper to prevent metal stainless steel from affecting the distribution of the magnetic field. The heating material rack 31 includes 5 layers of material plates, with a total material placement area of ​​0.5m2. The heating wire heating plate 32 is fixed under each layer of material plates by screws, and heat is conducted through the aluminum plate or copper plate during heating; each heating wire heating plate 32 of the entire heating device adopts a separate PID control to ensure the consistency of the heating temperature and rate of each heating plate; the material is placed through the material tray and placed in the material rack. In the freeze-drying sublimation stage, according to the characteristics of the material substrate, the heating process is carried out by graded and segmented heating through the set PID intelligent temperature control program, thereby completing the sublimation process of the material.

[0038] In this specific embodiment, the vacuum device 4 includes a rotary vane vacuum pump and a stainless steel pipe. The rotary vane vacuum pump is connected to the freeze-drying chamber 6 through the stainless steel pipe. The rotary vane vacuum pump is fixed to the frame 7 by bolts. The vacuum degree can reach 5Pa under no-load conditions. The outlet of the rotary vane vacuum pump reserves a DN40 interface for an external pipe to facilitate the discharge of gas.

[0039] In this specific embodiment, the controller 5 includes a touch screen and a PLC control panel, the touch screen is arranged outside the frame 7, and the PLC control panel is arranged inside the frame 7. The controller 5 can intelligently set various stage parameters including cooling time, cooling temperature, magnetic field strength, magnetic field time, heating temperature, time and cavity vacuum pressure according to different agricultural product matrix characteristics. According to different agricultural product matrix characteristics, the cooling time, cooling temperature, magnetic field strength, magnetic field time, heating temperature, time and cavity vacuum pressure and other stage parameters are intelligently set. The entire processing process is completed "one-button automatic" in the intelligent control device, and can be equipped with a mobile phone APP function, which can remotely monitor the equipment through the mobile phone, thereby ensuring product quality, production safety and stability during the processing, and optimizing energy consumption.

[0040] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A magnetically controlled low-temperature freeze-drying device used in agricultural product processing, characterized in that: It comprises an intelligent magnetic field monitoring device, a freeze-drying cooling device, an intelligent heating device, a vacuuming device and a controller; the intelligent magnetic field monitoring device is used to control and detect the magnetic field strength of foods that are cooled rapidly, the freeze-drying cooling device is arranged outside the freeze-drying chamber for cooling and cooling the freeze-drying chamber, the intelligent heating device is arranged in the freeze-drying chamber for heating and sublimating the frozen agricultural products, the vacuuming device is used to vacuum the freeze-drying chamber, and the controller is used to control the operation of the entire equipment; wherein, the intelligent magnetic field monitoring device comprises a plurality of magnetic field rings with the same axial magnetic field strength, a magnetically controlled power controller and a magnetic field strength monitor, the plurality of magnetic field rings are connected in sequence to form a magnetic field ring group, the magnetically controlled power controller is used to control the magnetic field strength of the magnetic field ring group, and the magnetic field strength monitor is used to monitor the magnetic field strength of the magnetic field ring group.

2. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 1, characterized in that: It also includes a frame, and the intelligent magnetic field monitoring device, freeze-drying cooling device, intelligent heating device, vacuum device and controller are all arranged on the frame.

3. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 2, characterized in that: The frame is a rectangular box structure formed by welding a plurality of plate structures.

4. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 3, characterized in that: The intelligent magnetic field monitoring device is arranged on one side of the top of the frame, wherein the magnetic field monitoring control panel of the intelligent magnetic field monitoring device is installed on the outside of the frame, the control knob of the magnetic control power controller and the monitoring screen of the magnetic field strength monitor are arranged on the magnetic field monitoring control panel, and the magnetic field ring group includes 4 independent magnetic field rings, and the 4 magnetic field rings are evenly distributed in a cylindrical cavity along the axial direction, and two adjacent magnetic field rings are connected by bolts.

5. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 4, characterized in that: The magnetic field ring is a circular magnetic field ring composed of multiple turns of Helmholtz coils. The magnetic field ring combines the Biot-Savart law and performs magnetic field simulation of the coil through COMSOL simulation software, thereby determining the coil size and its placement position in the cylindrical cavity.

6. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 3, characterized in that: The freeze-drying and cooling device includes a freeze-drying chamber, a compressor, a condenser, an evaporator, a capillary tube and a heat exchanger arranged inside the frame. The evaporator is wrapped on the outer wall of the freeze-drying chamber. The compressor provides power for the entire freeze-drying and cooling device. The compressor extracts gaseous refrigerant from the evaporator, passes through the heat exchanger and presses it into the condenser. The gaseous refrigerant forms high-pressure and high-temperature gas in the compressor. The high-pressure gaseous refrigerant is liquefied when passing through the condenser to form low-temperature and high-pressure condensing agent, and the refrigerant is depressurized through the capillary tube, thereby re-entering the evaporator through the heat exchanger. The evaporator is coiled outside the freeze-drying chamber, and the energy is taken away by the inside of the freeze-drying chamber. The refrigerant forms gas, and the gaseous refrigerant is extracted by the compressor and pumped into the condenser. In this way, the refrigerant is circulated in a closed manner to continuously cool and cool the freeze-drying chamber.

7. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 6, characterized in that: The intelligent heating device is arranged in the freeze-drying chamber, and the intelligent heating device includes a heating material rack, an electric heating wire heating plate and a PID controller; the heating material rack includes multiple layers of material plates arranged at intervals up and down, and the electric heating wire heating plate is arranged under each layer of material plates. Each of the electric heating wire heating plates is provided with a separate PID controller, and the temperature is increased in stages and sections through the intelligent temperature control program of the PID controller, thereby completing the sublimation process of the material.

8. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 7, characterized in that: The heating material rack is made of aluminum or copper, and includes 5 layers of material plates. The heating wire heating plate is fixed under each layer of the material plate by screws.

9. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 2, characterized in that: The vacuum pump comprises a rotary vane vacuum pump and a stainless steel pipe, the rotary vane vacuum pump is connected to the freeze-drying chamber via the stainless steel pipe, the rotary vane vacuum pump is fixed to the frame via bolts, and an outlet of the rotary vane vacuum pump has a reserved interface for an external pipe to facilitate the discharge of gas.

10. The magnetically controlled low-temperature freeze-drying equipment for agricultural product processing according to claim 2, characterized in that: The controller includes a touch screen and a PLC control panel, the touch screen is arranged outside the frame, and the PLC control panel is arranged inside the frame. The controller can intelligently set various stage parameters including cooling time, cooling temperature, magnetic field strength, magnetic field time, heating temperature, time and cavity vacuum pressure according to different agricultural product matrix characteristics.

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