Partitioned adjustable vacuum radio frequency freeze drying device

Abstract

The invention discloses a partitioned adjustable vacuum radio frequency freeze drying device which comprises a machine body, a drying chamber, a vacuum system, a freezing system, a radio frequency heating system and a sensing control system. The drying chamber is arranged at the upper part of the machine body, the drying chamber comprises a barrel-shaped area, and the drying chamber further comprises a radio frequency electrode plate and a drying tray; and an aluminum refrigeration pipe is coiled on the rear wall of the drying chamber. The device is simple in structure, convenient to use, complete in function and capable of conducting freeze-drying processing on wide non-metal products, especially agricultural and sideline products. The device combines the advantages of freeze drying and radio frequency drying, has the characteristics of quick freezing, uniform heating and the like, and has the advantages of high drying rate, low drying energy consumption, good drying quality and the like compared with traditional drying equipment.

Description

Technical Field

[0001] The invention relates to the technical field of drying processing, and in particular to a partition-adjustable vacuum radio frequency freeze-drying device. Background Art

[0002] Freeze drying is a drying technology that freezes materials containing a large amount of water to turn the water into solid ice, and then allows the ice to sublime directly into water vapor in a vacuum environment to remove the water. Specifically, freeze drying can be divided into three stages. The first is the pre-freezing stage, in which the material to be dried is quickly cooled to below its eutectic point (the temperature at which the solute and solvent in the solution crystallize simultaneously) so that the water in the material is completely frozen into ice, usually below -20°C. The second is the sublimation drying stage, in which heat is provided to the pre-frozen material in a high vacuum environment (generally at a pressure of 10-100Pa) to allow the ice to sublime directly into water vapor.

[0003] In a vacuum environment, the saturated vapor pressure of water is very low. After the water molecules on the surface of the ice crystals gain enough energy, they directly escape and become water vapor. Finally, after the analytical drying stage, after sublimation drying, some bound water adsorbed on the solid frame will remain in the material. It is necessary to further increase the temperature to remove this water in a vacuum. Radio frequency heating is an efficient and unique drying technology, which has been widely studied in industrial production and scientific research. The core component of radio frequency drying is the radio frequency generator, which generates a high-frequency alternating electromagnetic field with a frequency between 3kHz-300MHz. When the material to be dried is placed in the electromagnetic field formed by the radio frequency electrode, the polar molecules such as water molecules and ions in the material will vibrate and rotate rapidly under the action of the high-frequency electric field. This molecular movement generates a large amount of frictional heat, which causes the material to heat up. After absorbing the heat, the water gradually vaporizes and is then discharged from the pores of the material in the form of water vapor to achieve a drying effect. Radio frequency drying can directly penetrate the material, allowing the material to be heated from the inside out at the same time, so even large and thick materials can be dried evenly. In addition, radio frequency energy preferentially acts on polar water molecules, and the water in the material absorbs more energy than other components. While efficiently removing water, it retains heat-sensitive substances and nutrients to the greatest extent, such as vitamins in food and active ingredients in medicines.

[0004] In the existing freeze drying equipment, during the sublimation stage, the equipment stops refrigerating the materials in the drying chamber to allow the material temperature to rise gradually; or uses electric heating to heat the materials. The former takes a long time, often one or two days, and this process consumes a lot of energy. The latter uses electric heating, which will cause the temperature to rise too quickly, causing the ice crystals of the material to melt or the heating to be uneven, thus affecting the product quality.

[0005] The combination of radio frequency heating and freeze drying technology can effectively shorten the time required for freeze drying and improve the uniformity of drying by taking advantage of the good penetration and uniformity of radio frequency heating. In addition, in a vacuum environment, radio frequency heating does not require too much power, which saves energy and reduces electromagnetic radiation. Summary of the invention

[0006] In view of this, the present invention provides a partition-adjustable vacuum radio frequency freeze-drying device.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A partition-adjustable vacuum radio frequency freeze-drying device, comprising:

[0009] A machine body, a drying chamber, a vacuum system, a freezing system, a radio frequency heating system and a sensor control system; the drying chamber is arranged on the upper part of the machine body, the drying chamber includes a barrel-shaped area, and the drying chamber also includes a radio frequency electrode plate and a drying material tray; an aluminum refrigeration pipe is spirally arranged on the rear wall of the drying chamber.

[0010] Preferably, the vacuum system includes a vacuum pump, a vacuum solenoid valve and a vacuum gauge. The vacuum pump is located below the drying chamber and is connected to the drying chamber through a vacuum pipe; the vacuum gauge is located on the upper part of the machine body.

[0011] Through the above operation, the vacuum condition in the drying chamber can be monitored.

[0012] Preferably, the refrigeration system includes a compressor, a liquid storage tank, an axial flow fan and a refrigeration pipe; the compressor is located in the lower chamber of the machine body and is connected to the liquid storage tank and the drying chamber through a copper pipe; and the liquid storage tank is filled with a circulating hydrocarbon refrigerant R600a.

[0013] Through the above operation, it can be used for low-temperature refrigeration, which not only has strong cooling capacity and good fluidity but is also environmentally friendly.

[0014] Preferably, the RF heating system includes a RF generator, an adjustable heating electrode, a fixed lower electrode plate, a partitioned electromagnetic shielding plate and a shielding door; the RF generator is installed in an electric control cabinet; and the adjustable heating electrode is installed inside a drying chamber.

[0015] Through the above operation, low-frequency alternating current can be converted into high-frequency alternating current and a radio frequency signal of a specific frequency can be emitted; and the spacing between the electrode plates can be controlled.

[0016] Preferably, the sensor control system includes a temperature sensor, a vacuum sensor, a human-machine interaction panel and a PLC controller; the temperature sensor and the vacuum sensor are located inside the drying chamber; and the human-machine interaction panel is installed on the electric control cabinet.

[0017] Through the above operations, relevant process parameters can be modified and parameters in the drying room can be monitored.

[0018] Preferably, there are three groups of radio frequency heating devices in the drying chamber, and the plate spacing and radio frequency power of each group of radio frequency heating devices can be freely adjusted and controlled independently; an electromagnetic shielding plate is provided under the radio frequency heating plates.

[0019] Through the above operations, the radio frequency signals between different areas can be effectively isolated.

[0020] Preferably, the temperature sensor is made of optical fiber material, and its position can be freely adjusted; the optical fiber temperature sensor is electrically connected to the sensor control system.

[0021] Through the above operation, the temperature sensor can be inserted into the material to accurately measure the temperature; the measured temperature can be used to control the switch of the RF generator.

[0022] Preferably, the machine body is equipped with an electromagnetic shielding door, the middle of the electromagnetic shielding door is transparent tempered glass for observing the state of materials inside the drying chamber, and the inner wall of the electromagnetic shielding door is provided with an electromagnetic shielding net, and the material of the electromagnetic shielding net is copper wire.

[0023] Through the above operations, the leakage of electromagnetic radiation can be effectively prevented.

[0024] Preferably, the drying tray is made of non-metallic material polytetrafluoroethylene, and its bottom is covered with round holes.

[0025] The above operation is beneficial to the volatilization of moisture in the material.

[0026] Preferably, an alarm indicator light is installed on the top of the body, and the indicator light is red when the radio frequency generator is working, and the indicator light is green when the radio frequency generator stops working.

[0027] Compared with the prior art, the present invention has achieved the following technical effects:

[0028] (1) The present invention has a simple structure, is easy to use, and has complete functions, and can be used to freeze-dry a wide range of non-metallic products, especially agricultural and sideline products;

[0029] (2) The present invention combines radio frequency heating with freeze drying, solving the problems of long sublimation time, uneven drying and high energy consumption in freeze drying;

[0030] (3) The RF plate spacing, RF heating temperature, and power of each RF heating area of ​​the present invention can be adjusted individually, which has significant advantages in experimental research applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a front view of a partition-adjustable vacuum radio frequency freeze-drying device of the present invention;

[0032] Figure 2 It is a cross-sectional view of a partition-adjustable vacuum radio frequency freeze-drying device of the present invention;

[0033] Figure 3 This is a schematic diagram of the drying chamber structure of a partition-adjustable vacuum radio frequency freeze-drying device of the present invention;

[0034] Figure 4 It is a schematic diagram of a drying tray of a partition-adjustable vacuum radio frequency freeze-drying device of the present invention;

[0035] In the figure, 1-machine body, 2-drying chamber, 301-vacuum pump, 302-vacuum solenoid valve, 303-vacuum gauge, 401-compressor, 402-liquid storage tank, 403-axial flow fan, 404-refrigeration pipe, 501-RF generator, 502-adjustable RF upper plate, 503-fixed lower plate, 504-electromagnetic shielding plate, 505-electromagnetic shielding door, 601-optical fiber temperature sensor, 602-vacuum sensor, 603-human-computer interactive touch screen control screen, 604-PLC controller, 7-electric control cabinet, 8-drying tray, 9-indicator light. DETAILED DESCRIPTION

[0036] 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.

[0037] The present invention discloses a partition-adjustable vacuum radio frequency freeze-drying device, comprising:

[0038] The machine body 1, the drying chamber 2, the vacuum system 3, the freezing system 4, the radio frequency heating system 5 and the sensor control system 6; the drying chamber 2 is arranged on the upper part of the machine body 1, the drying chamber 2 includes a barrel area made of stainless steel material, and the drying chamber 2 also includes a radio frequency electrode plate and a drying material tray 8; an aluminum refrigeration pipe is spirally arranged on the rear wall of the drying chamber 2.

[0039] The vacuum system 3 includes a vacuum pump 301 , a vacuum solenoid valve 302 and a vacuum gauge 303 . The vacuum pump 301 is located below the drying chamber 2 and is connected to the drying chamber 2 through a vacuum pipe. The vacuum gauge 303 is located on the upper part of the machine body 1 .

[0040] The refrigeration system 4 includes a compressor 401, a liquid storage tank 402, an axial flow fan 403 and a refrigeration pipe 404; the compressor 401 is located in the lower chamber of the body 1, and is connected to the liquid storage tank 402 and the drying chamber 2 through a copper pipe; and the liquid storage tank 402 is filled with a circulating hydrocarbon refrigerant R600a, which is suitable for low-temperature refrigeration, has a strong cooling capacity, good fluidity and is environmentally friendly;

[0041] The RF heating system 5 includes an RF generator 501, an adjustable heating electrode 502, a fixed lower electrode plate 503, a partitioned electromagnetic shielding plate 504 and a shielding door 505; the RF generator 501 is installed in the electric control cabinet 7, which can convert low-frequency alternating current into high-frequency alternating current and emit a RF signal of a specific frequency; the adjustable heating electrode 502 is installed inside the drying chamber, which can control the spacing between the electrode plates.

[0042] The sensor control system 6 includes a temperature sensor 601, a vacuum sensor 602, a human-machine interaction panel 603 and a PLC controller 604; the temperature sensor 601 and the vacuum sensor 602 are located inside the drying chamber 2; the human-machine interaction panel 603 is installed on the electrical control cabinet 7, and the relevant process parameters can be modified and the parameters inside the drying chamber can be monitored through the touch screen.

[0043] There are three groups of RF heating devices in the drying chamber 2. The distance between the plates and the RF power of each group of RF heating devices can be freely adjusted and controlled independently. An electromagnetic shielding plate 504 is provided under each of the RF heating plates.

[0044] The temperature sensor is made of optical fiber material and its position can be freely adjusted; the optical fiber temperature sensor 601 is electrically connected to the sensor control system 6.

[0045] The machine body 1 is provided with an electromagnetic shielding door 505, the middle of which is a transparent tempered glass for observing the state of materials inside the drying chamber 2. The inner wall of the electromagnetic shielding door 505 is provided with an electromagnetic shielding net made of copper wire.

[0046] The drying material tray 8 is made of non-metallic material polytetrafluoroethylene, and its bottom is covered with round holes.

[0047] An alarm indicator light 9 is installed on the top of the body 1. The indicator light 9 is red when the radio frequency generator 501 is working, and is green when the radio frequency generator 501 stops working.

[0048] Working principle:

[0049] First, before putting the material in, start the refrigeration system, and the compressor will work to reduce the temperature of the cold trap to the set value, and the temperature of the drying chamber will be reduced to the set temperature; pre-freeze the material to be dried in advance, spread it flat in the polytetrafluoroethylene tray, open the shielding door, put the material in the middle of the electrode plate, insert the optical fiber temperature sensor into the material, and close the shielding door;

[0050] Secondly, set the drying process parameters on the human-machine interactive control panel and adjust the plate spacing and temperature required for each area. During the sublimation stage, the RF heating plate automatically starts, the safety indicator turns red, and the material temperature transmitted by the optical fiber temperature sensor can be observed on the monitoring panel. When the materials in each area reach the set temperature, the RF generator stops working and the safety indicator turns green.

[0051] Finally, after completing the set drying stage, the RF generator automatically turns off, the air-breaking solenoid valve opens, and the equipment returns to normal pressure; the material is taken out to obtain a dry product.

[0052] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A zone-adjustable vacuum radio frequency freeze-drying device, characterized in that: include: A machine body (1), a drying chamber (2), a vacuum system (3), a freezing system (4), a radio frequency heating system (5) and a sensor control system (6); the drying chamber (2) is arranged on the upper part of the machine body (1), the drying chamber (2) comprises a barrel-shaped area, and the drying chamber (2) also comprises a radio frequency electrode plate and a drying material tray (8); an aluminum refrigeration pipe is coiled on the rear wall of the drying chamber (2).

2. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: The vacuum system (3) comprises a vacuum pump (301), a vacuum solenoid valve (302) and a vacuum gauge (303); the vacuum pump (301) is located below the drying chamber (2) and is connected to the drying chamber (2) via a vacuum pipe; the vacuum gauge (303) is located on the upper part of the machine body (1).

3. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: The refrigeration system (4) comprises a compressor (401), a liquid storage tank (402), an axial flow fan (403) and a refrigeration pipe (404); the compressor (401) is located in the lower chamber of the machine body (1) and is connected to the liquid storage tank (402) and the drying chamber (2) through a copper pipe; and the liquid storage tank (402) is filled with a circulating hydrocarbon refrigerant R600a.

4. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: The radio frequency heating system (5) comprises a radio frequency generator (501), an adjustable heating electrode (502), a fixed lower electrode plate (503), a partitioned electromagnetic shielding plate (504) and a shielding door (505); the radio frequency generator (501) is installed in an electric control cabinet (7); and the adjustable heating electrode (502) is installed inside a drying chamber.

5. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: The sensor control system (6) comprises a temperature sensor (601), a vacuum sensor (602), a human-machine interaction panel (603) and a PLC controller (604); the temperature sensor (601) and the vacuum sensor (602) are located inside the drying chamber (2); and the human-machine interaction panel (603) is installed on the electric control cabinet (7).

6. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: There are three groups of radio frequency heating devices in the drying chamber (2), and the distance between the plates and the radio frequency power of each group of radio frequency heating devices can be freely adjusted and controlled independently; an electromagnetic shielding plate (504) is provided under each of the radio frequency heating plates.

7. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: The temperature sensor is made of optical fiber material and its position can be freely adjusted; the optical fiber temperature sensor (601) is electrically connected to the sensor control system (6).

8. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: The machine body (1) is equipped with an electromagnetic shielding door (505), the middle of the electromagnetic shielding door (505) is transparent tempered glass for observing the state of materials inside the drying chamber (2), and the inner wall surface of the electromagnetic shielding door (505) is provided with an electromagnetic shielding net, and the material of the electromagnetic shielding net is copper wire.

9. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: The drying material tray (8) is made of a non-metallic material, polytetrafluoroethylene, and its bottom is covered with round holes.

10. The partition-adjustable vacuum radio frequency freeze-drying device according to claim 1, characterized in that: An alarm indicator light (9) is installed on the top of the machine body (1); when the radio frequency generator (501) is working, the indicator light (9) is red, and when the radio frequency generator (501) stops working, the indicator light (9) is green.

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