CN106839661B - Microwave vacuum freeze drying equipment and material drying method - Google Patents
Microwave vacuum freeze drying equipment and material drying method Download PDFInfo
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- CN106839661B CN106839661B CN201710160681.1A CN201710160681A CN106839661B CN 106839661 B CN106839661 B CN 106839661B CN 201710160681 A CN201710160681 A CN 201710160681A CN 106839661 B CN106839661 B CN 106839661B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
- F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
- F26B5/06—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum the process involving freezing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
- F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
- F26B5/048—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum in combination with heat developed by electro-magnetic means, e.g. microwave energy
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Abstract
The utility model provides microwave vacuum freeze drying equipment and a drying method of aerogel materials, wherein the microwave vacuum freeze drying equipment comprises a microwave bin, a freeze drying bin, a microwave generator with continuously adjustable emission power, a refrigerating system, a vacuum water capturing system, a pressure regulating system, a vacuum pump and a microcomputer central control system, wherein the freeze drying bin is arranged in the microwave bin, the microwave generator with continuously adjustable emission power is fixed on the side wall of the microwave bin and uniformly and alternately arranged around the freeze drying bin, the refrigerating system is connected with the freeze drying bin and the vacuum water capturing system, the vacuum water capturing system is connected with the vacuum pump and the freeze drying bin, the pressure regulating system is connected with the vacuum pump and the freeze drying bin, and the microcomputer central control system is respectively connected with the microwave generator and the pressure regulating system so as to control microwave power and pressure.
Description
Technical Field
The present utility model relates to a freeze-drying apparatus, and more particularly, to a vacuum freeze-drying apparatus using microwaves as a heating source and a method for drying aerogel materials.
Background
The vacuum freeze drying technology has the advantages of thorough dehydration, capability of keeping the appearance and microstructure of the product to the maximum extent, quick rehydration and increasing attention of people. The method is a drying technology for directly sublimating water and other solvents in the material into gas under the condition of high vacuum degree without melting by freezing the water-containing material below the eutectic point temperature. Conventional vacuum freeze drying generally adopts a heat conduction mode to provide sublimation heat, and the heating mode has long drying period, high energy consumption and relatively high cost. Meanwhile, the heating mode is carried out at a higher temperature, so that the nutritional ingredients of the food can be destroyed when the food is dried, bacteria are easy to breed, and the health of people is threatened. These drawbacks severely limit the development of vacuum freeze-drying techniques.
Microwave vacuum freeze drying techniques can overcome the above-mentioned disadvantages. It is a provider of latent heat of sublimation by microwave heating instead of conduction or infrared radiation heating in conventional lyophilization techniques. Under the action of microwaves, dipole molecules in the heated material reciprocate at high frequency to generate internal friction heat so as to raise the temperature of the heated material, and the internal and external heating and the simultaneous temperature raising of the material can be realized without any heat conduction process, so that the phenomenon of uneven heating can not be caused.
However, one of the biggest problems plaguing researchers in the field of microwave vacuum freeze-drying is the ease of glow discharge when heated under low pressure conditions using microwaves. In the microwave drying process, the vacuum degree is improved, so that the breakdown field intensity of the gas is reduced, gas molecules are easily ionized into ions, and a glow discharge phenomenon occurs. This can result in significant loss of microwave energy, potentially damaging equipment, and also in significant damage to the dried sample. In addition, in the later stages of microwave vacuum freeze drying, as the moisture content of the sample decreases, the energy required for sublimation also gradually decreases. If the material is continuously heated with high power microwaves, not only can the material burn out, affecting the quality of the freeze-dried product, but also the lifetime of the equipment may be reduced.
The Chinese patent application No. 03249124.7 entitled "microwave freeze drying apparatus for food production" adopts microwave magnetron to heat and dry food, so that the inside and outside of food can be heated simultaneously, and the moisture in the center and the outside of food can be evaporated simultaneously, thus the nutrition components of the dried food can not be destroyed, the drying period of food is shortened by 5-6 times, and the cost of mass production is reduced. However, this patent does not address the glow discharge problem of microwaves under low pressure conditions. In addition, the positions of the materials and the tray are relatively static, and the uniformity of the heating effect of the product is affected to a certain extent.
The utility model relates to a Chinese patent with application number 200910181720.1 and name of 'double-bin differential pressure type microwave vacuum freeze drying equipment', and discloses microwave vacuum freeze drying equipment, wherein a bin body of the equipment is divided into a first bin and a second bin by a transmission flow separation plate, a magnetron is positioned in the first bin, the vacuum degree of the first bin is smaller than a discharge critical value, a material bearing device is positioned in the second bin, and the second bin is connected with a cold trap through a shielding flow separation plate. However, the method of separating the space where the magnetron and the material are located and allowing microwaves to enter the bin body where the material is located through the wave-transparent material cannot fundamentally inhibit the occurrence of glow discharge phenomenon, because the second bin is still in a high vacuum environment, and microwaves are discharged under such vacuum. In addition, even if microwaves enter the first bin from the crumple inlet and are reflected by the bin wall to form a multimode microwave field in the second bin, the uniformity of microwave heating is greatly affected due to the fixed position of the sample to be freeze-dried.
On the other hand, in the existing drying method mainly adopted for aerogel materials, supercritical drying can well eliminate capillary tension in the drying process, so that the integrity of the materials is maintained, but the method has high equipment requirements, high cost and high danger in the operation process; conventional vacuum freeze drying reduces the cost of equipment to a certain extent, but because the equipment is dried by adopting a conduction heating mode, the integrity of aerogel materials is damaged due to uneven heating; the normal pressure drying greatly reduces the drying cost, but the material needs to be subjected to sufficient surface modification before drying, the drying period is prolonged, and the drying efficiency is reduced. Therefore, it is highly desirable to develop a drying method that can uniformly heat-dry aerogel materials, has a high drying rate, and greatly increases the drying rate with low energy consumption.
Disclosure of Invention
The present utility model has been made in view of the above problems, and an object of the present utility model is to provide a microwave vacuum freeze-drying apparatus which well solves the glow discharge phenomenon. Another object of the present method is to provide a method for drying materials with uniform heating, fast drying rate, high drying rate and low energy consumption.
In order to achieve the above object, according to one aspect of the present utility model, there is provided a microwave vacuum freeze drying apparatus, comprising a microwave bin, a freeze drying bin, a microwave generator with continuously adjustable emission power, a refrigerating system, a vacuum water capturing system, a pressure regulating system, a vacuum pump and a microcomputer central control system, wherein the freeze drying bin is disposed in the microwave bin, the microwave generator with continuously adjustable emission power is fixed on a side wall of the microwave bin, uniformly and alternately arranged around the freeze drying bin, the refrigerating system is connected with the freeze drying bin and the vacuum water capturing system, the vacuum water capturing system is connected with the vacuum pump and the freeze drying bin, the pressure regulating system is connected with the vacuum pump and the freeze drying bin, and the microcomputer central control system is respectively connected with the microwave generator and the pressure regulating system to control the microwave power generated by the microwave generator and the pressure regulated by the pressure regulating system.
According to some embodiments of the utility model, the microcomputer central control system controls the microwave generator and the pressure regulating system in a preset combined control mode so that the microwave power generated by the microwave generator corresponds to the pressure regulated by the pressure regulating system.
According to some embodiments of the utility model, a turntable which can horizontally rotate and is driven by a motor is arranged at the bottom of the freeze-drying bin, and a plurality of micro conveyor belts which can move back and forth are symmetrically arranged on the turntable.
According to some embodiments of the utility model, the microcomputer central control system is respectively connected with the turntable and the micro conveyor belt to respectively control the rotation speed of the turntable and the transmission frequency of the micro conveyor belt.
According to some embodiments of the utility model, the microcomputer central control system adjusts the rotation speed of the turntable according to the microwave power and the pressure adjusted by the combined control mode.
According to some embodiments of the utility model, the turntable is capable of rotating horizontally, the part passing through the microwave bin between the turntable and the motor is connected by using a metal shielding overflow plate with sieve holes with specified sizes, and a sealing gasket is arranged at the position passing through the freeze drying bin.
According to some embodiments of the utility model, the microwave bin is made of a metallic wave-impermeable material, and the lyophilization bin is made of a non-metallic wave-transparent material and is sized in a predetermined ratio to the microwave bin.
According to some embodiments of the utility model, the refrigerating system is connected with the freeze-drying bin and the vacuum water catching system through a pipeline, a valve is arranged in the pipeline, the opening and the closing of the refrigerating system and the freeze-drying bin and the vacuum water catching system are controlled through the valve, and the pipeline between the refrigerating system and the microwave bin is connected by a metal shielding overflow plate with a mesh of a specified size.
According to some embodiments of the utility model, the vacuum water capturing system is connected with the vacuum pump, the pressure regulating system and the freeze-drying bin through pipelines, the pipelines between the vacuum water capturing system and the microwave bin are connected through metal shielding overflow plates with holes with specified sizes, the pipelines are connected with the freeze-drying bin through metal shielding overflow plates with holes with specified sizes, and a defrosting valve is arranged at the lower part of the vacuum water capturing system.
According to some embodiments of the utility model, the continuously adjustable transmission power microwave generator keeps the frequency of the transmitted microwaves constant while realizing the continuously adjustable transmission power.
According to another aspect of the present utility model, there is provided a method for drying a material, using a microwave vacuum freeze-drying apparatus, the microwave vacuum freeze-drying apparatus including a microwave bin, a freeze-drying bin, a microwave generator with continuously adjustable emission power, a refrigerating system, a vacuum water capturing system, a pressure regulating system, a vacuum pump and a microcomputer central control system, the freeze-drying bin being disposed inside the microwave bin, the microwave generator with continuously adjustable emission power being fixed on a side wall of the microwave bin and uniformly arranged around the freeze-drying bin in a cross manner, the refrigerating system being connected to the freeze-drying bin and the vacuum water capturing system, the vacuum water capturing system being connected to the vacuum pump and the freeze-drying bin, the pressure regulating system being connected to the vacuum pump and the freeze-drying bin, the method for drying a material comprising the steps of:
1) Placing the wet material in the lyophilization chamber;
2) Freezing the wet material; and
3) And controlling the microwave generator to generate microwaves through the microcomputer central control system and regulating the pressure through the pressure regulating system so as to heat the material to dry the material, thereby obtaining the freeze-dried material.
According to some embodiments of the utility model, in the step 3), the microcomputer central control system controls the microwave generator and the pressure regulating system in a predetermined joint control mode so that the microwave power generated by the microwave generator corresponds to the pressure regulated by the pressure regulating system.
According to some embodiments of the utility model, a turntable which can horizontally rotate and is driven by a motor is arranged at the bottom of the freeze-drying bin, a plurality of micro-conveyor belts which can reciprocate along the radial direction of the turntable are symmetrically arranged on the turntable, and in the step 3), the microcomputer central control system also controls the rotation speed of the turntable and the transmission frequency of the micro-conveyor belts.
According to some embodiments of the utility model, the material is an aerogel material.
According to some embodiments of the utility model, the aerogel material is a cellulosic SiO2 composite aerogel.
The utility model has at least one of the following technical effects:
can effectively dry food, and has uniform heating and high speed.
2. The rotatable turntable is arranged on the freeze-drying bin to generate the effect of microwave stirring, so that the microwave energy field is more uniform, and the occurrence of glow discharge under low pressure is well avoided.
3. The central control system uniformly controls the microwave emission power, the refrigerator and the rotary table at the bottom of the freeze-drying bin to the maximum extent, so that the freeze-drying effect of materials is guaranteed.
4. The method can also dry the aerogel material with wide application prospect, overcomes the defects of long time consumption and high energy consumption of the traditional freeze-drying process, and can be suitable for large-scale industrial production of the aerogel material.
The utility model is described in further detail below with reference to the drawings and the detailed description, but does not limit the utility model in any way.
Drawings
Fig. 1 is a schematic view of a structure of a microwave vacuum freeze-drying apparatus according to an embodiment of the present utility model;
fig. 2 is a top view of a turntable of the microwave vacuum freeze drying apparatus of fig. 1.
In the figure: 1. 2 parts of microwave generator, 2 parts of microwave bin, 3 parts of freeze-drying bin, 4 parts of vacuum water capturing system, 5 parts of pressure regulating system, 6 parts of vacuum pump, 7 parts of refrigerating system, 8-1 parts of valve 1,8-2 parts of valve 2,9 parts of sealing gasket, 10 parts of motor, 11 parts of metal shielding overflow plate, 12 parts of rotary table, 13-1 parts of freeze-drying bin gate, 13-2 parts of microwave bin gate, 14 parts of defrosting valve, 15 parts of microcomputer central control system, 16 parts of micro-conveyor belt
Description of the embodiments
In one aspect of the present utility model, there is provided a microwave vacuum freeze-drying apparatus (hereinafter referred to as the apparatus of the present utility model) comprising a microwave oven 2, a freeze-drying oven 3, a continuously adjustable emission power microwave generator 1, a refrigeration system 7, a vacuum water capturing system 4, a pressure regulating system 5, a vacuum pump 6 and a microcomputer central control system 15.
The microwave generator 1 with continuously adjustable transmitting power and the pressure regulating system 5 can be uniformly controlled by the microcomputer central control system 15, and the operator sets a program according to actual needs, so that the microcomputer central control system 15 can automatically control and regulate various parameters to finish drying of the materials.
The microwave cabin 2 is made of a metallic wave-impermeable material, such as stainless steel, which may be cube-shaped. The freeze-drying bin 3 is arranged inside the microwave bin 2 and is located at the center of the lower part, and the size is in a proportion to the microwave bin 2, and in general, the proportion is 35% -85%, preferably 40% -80%, more preferably 40% -75%, and most preferably 45% -65%.
The freeze-drying bin 3 is made of non-metal wave-transmitting materials such as polytetrafluoroethylene, glass or ceramic, and the like, and polytetrafluoroethylene materials are selected in the embodiment, so that the microwave can be ensured to enter, the microwave loss is reduced, certain strength is achieved, and microwave leakage can not be generated under the condition of high vacuum degree.
The microwave generator 1 with continuously adjustable transmitting power is fixed on the side wall of the microwave bin 2, uniformly and crosswise arranged around the freeze-drying bin 3, and is connected with and controlled by the microcomputer central control system 15. Preferably, the microwave generator 1 with continuously adjustable transmission power can continuously adjust the transmission power of microwaves under the condition that the frequency of the transmitted microwaves is unchanged.
The bottom of the freeze-drying bin 3 is provided with a turntable 12 which is driven by a motor 10 and can horizontally rotate, and 8 micro-conveyor belts 16 which can reciprocate in the radial direction of the turntable 12 are symmetrically arranged on the turntable. The horizontally rotatable turntable 12 and the micro conveyor 16 on the turntable 12 are made of a polytetrafluoroethylene material that does not absorb microwaves. The part passing through the microwave bin 2 between the turntable 12 and the motor 10 is connected by using a metal shielding overflow plate 11 with a sieve opening of a certain size, and a sealing gasket 9 is arranged at the position passing through the freeze-drying bin 3. The micro conveyor 16 ensures that the material is heated more uniformly while rotating with the turntable 12 and also moving in a direction perpendicular to the plane.
The refrigerating system 7 is connected with the freeze-drying bin 3 and the vacuum water-catching system 4 through pipelines, and the opening and closing of the refrigerating system and the vacuum water-catching system can be controlled through valves. The pipes between the refrigerating system 7 and the microwave bin 2 are connected by a metal shielding flow-through plate 11 with a mesh of a certain size. The pipeline can be made of a tetrafluoro glass fiber material. The tetrafluoro glass fiber material is a microwave low-loss material, and the material can ensure that the part extending into the microwave bin does not absorb microwave energy.
The vacuum water capturing system 4 can absorb sublimated gas in the drying process, is connected with the vacuum pump, the pressure regulating system and the freeze-drying bin through pipelines, and the pipelines between the vacuum water capturing system 4 and the microwave bin 2 are connected through a metal shielding overflow plate 11 with sieve holes with a certain size. The pipeline is made of tetrafluoro glass fiber material, and is connected with the freeze-drying bin 3 through a metal shielding overflow plate 11 with sieve holes with a certain size, so that microwaves are prevented from entering the pipeline. A defrosting valve 14 is attached to the lower part of the vacuum water capturing system 4.
The apparatus described above may be used for drying materials. The method of the utility model is based on the traditional vacuum freeze drying, and provides the sublimation latent heat for drying the materials by microwave heating.
In practice, the material is placed in a lyophilization chamber 3. The microwave emitted by the microwave generator 1 can be added to the material through the wall of the freeze-drying bin 3, and the microwaves which do not enter the freeze-drying bin 3 can be reflected by the inner wall of the microwave bin 2 and finally enter the freeze-drying bin 3 to be absorbed by the material. The microcomputer central control system 15 controls and adjusts parameters such as a change mode of microwave power, a change mode and a change amplitude of pressure, a relative change matching mode of pressure and microwave power, the rotating speed of the rotating disc 12, the movement frequency of the micro conveyor belt 16 and the like through preset program setting, so that the sample to be freeze-dried is dried through microwave application under the vacuum condition.
The apparatus of the present utility model and the method of drying material using the same will now be described with reference to fig. 1.
Fig. 1 is a schematic structural view of an embodiment of the apparatus of the present utility model. The equipment comprises a microwave generator 1 with continuously adjustable emission power, a microwave bin 2, a freeze-drying bin 3, a vacuum water catching system 4, a pressure regulating system 5, a vacuum pump 6, a refrigerating system 7, a motor 10, a microcomputer central control system 15, a micro-conveyor belt 16 and auxiliary devices.
The microwave generator 1 with continuously adjustable transmitting power is used as a provider of the microwave heating source, the frequency is fixed to 2450MHz, the microwave generator is arranged on the inner wall of the microwave bin 2 and uniformly and crosswise arranged around the freeze-drying bin 3, and therefore released microwaves can be more uniformly added to the freeze-drying bin 3 under the mediation of a microcomputer central control system.
The microwave bin 2 is cube-shaped and is made of metal wave-impermeable materials such as stainless steel, and the whole microwave bin is in a normal pressure environment.
The freeze-drying bin 3 is arranged at the middle position of the bottom of the microwave bin 2, and the size of the freeze-drying bin is in a certain proportion with the microwave bin 2, for example, the proportion is 45-65%.
The vacuum water capturing system 4 is connected with the pressure regulating system 5 and the vacuum pump 6 through tetrafluoro glass fiber pipelines in sequence, the right side passes through the microwave bin 2 through the pipelines and is finally connected with the freeze-drying bin 3, the contacted part is connected with the metal shielding overflow plate 11 with certain sieve holes, microwaves in the microwave bin 2 are prevented from leaking, and the microwaves in the freeze-drying bin 3 do not enter the pipelines.
The pressure regulating system 5 can properly increase the working pressure by the microcomputer central control system within a proper range of 0-100pa when the pressure meets the freeze-drying requirement, so that the field intensity threshold corresponding to discharge is increased, and the glow discharge phenomenon can not occur.
One side of the refrigerating system 7 passes through the microwave bin 2 through a pipeline and is connected with the freeze-drying bin 3, and the part passing through the microwave bin 2 is connected by a metal shielding overflow plate with sieve holes with specified sizes, so that microwaves in the microwave bin 2 are prevented from leaking. The valve 8-1 can be opened and closed, the valve 8-1 is opened when the material is pre-frozen, the material is quickly coagulated, the valve 8-1 is closed when the material is frozen, and the vacuum pump 6 starts to work. The other side of the refrigerating system 7 is connected with the vacuum water catching system 4 through a pipeline, and the valve 8-2 can be opened and closed.
The parts of the motor 10 extending into the microwave bin 2 and the freeze-drying bin 3 are made of tetrafluoro glass fiber materials, and the parts penetrating through the microwave bin 2 are connected by a metal shielding overcurrent plate 11 with a certain sieve mesh, so that the microwaves in the microwave bin 2 are prevented from leaking. The part passing through the freeze-drying bin 3 is provided with a sealing gasket 9, so that the tightness and the vacuum degree of the freeze-drying bin 3 are ensured.
The metal shielding current passing plate 11 with the sieve holes with the specified size is made of a metal copper plate, and the sieve holes on the metal shielding current passing plate are precisely measured and calculated, so that microwave leakage can be prevented.
The turntable 12 is made of polytetrafluoroethylene material and is in a disc shape. 8 micro-conveyor belts 16 are piled up around the center on the turntable 12, the micro-conveyor belts 16 are made of polytetrafluoroethylene materials, and the microcomputer central control system 15 controls the rotating speed of the turntable and the moving frequency of the micro-conveyor belts, so that the materials can move in the direction of a vertical plane while rotating along with the turntable 12, and the materials are heated more uniformly. Microwave energy concentration is avoided to a certain extent, and the occurrence probability of glow discharge is reduced.
The microcomputer central control system 15 is programmed to automatically adjust parameters such as a change mode of microwave power, a change mode and a change amplitude of pressure, a relative change matching mode of pressure and microwave power, the rotating speed of a rotating disc, the moving frequency of a micro-conveyor belt and the like in the freeze-drying process of materials, so that the drying of the materials is completed.
Examples
In this example, the banana blocks were freeze-dried using the apparatus shown in fig. 1, and the specific operation procedure was as follows:
the microwave bin gate 13-2 and the freeze-drying bin gate 13-1 are opened and a plurality of banana pieces to be freeze-dried are respectively placed on the micro conveyor 16 on the turntable 12. The freeze-drying bin gate 13-1 and the microwave bin gate 13-2 are closed in sequence. The banana pieces were cut into 1cm x 1cm cube pieces in advance, spaced about 0.5cm apart from each other, and uniformly arranged on the micro conveyor 16.
The refrigeration system 7 and valves 8-1 and 8-2 are opened to freeze the banana blocks on the turntable 12 and rapidly reduce the vacuum water capture temperature to-20 ℃.
The microcomputer central control system is programmed to automatically adjust parameters such as a change mode of microwave power, a change mode and change amplitude of pressure, a relative change matching mode of pressure and microwave power, the rotating speed of a rotating disc, the moving frequency of a micro conveyor belt and the like in the freeze drying process of the banana blocks.
When the banana blocks are frozen, the vacuum pump 6 is turned on while the valve 8-1 is closed, and at the moment, the vacuum degree in the freeze-drying bin 3 is rapidly increased.
When the pressure regulating system 5 shows a pressure drop in a preset pressure range, for example 5-30Pa, the microcomputer central control system will activate the motor 10 and the micro conveyor belt 16, so that the banana pieces start to move at a certain rate.
The microcomputer central control system starts a microwave generator 1 with continuously adjustable transmitting power, microwaves start to be collapsed into a freeze-drying bin 3, and frozen banana blocks are heated.
As the heating proceeds, the moisture in the banana pieces starts to sublimate, and the moisture finally enters the vacuum water capturing system 4 to be absorbed, so that the pressure in the freeze-drying bin 3 cannot be increased.
In the drying process, the microcomputer central control system can properly adjust and raise the pressure in the freeze-drying bin within the range of ensuring the pressure required by drying according to the pressure change displayed by the pressure adjusting system 5. In addition, the microcomputer central control system automatically adjusts the rotating speed of the turntable and the movement frequency of the micro conveyor belt 16 according to the change mode of microwave power, the change mode of pressure and the change amplitude.
As the emission power of the continuously power-adjustable microwave generator 1 gradually decreases, the banana pieces are dried close to completion. When the pressure regulation system 5 shows no more change in pressure, it is indicated that the banana pieces are completely dry.
When the indication number of the pressure regulating system 5 is not changed any more within a certain time, the microcomputer central control system sequentially turns off the microwave generator 1, the motor 10 and the micro conveyor belt 16 with continuously adjustable emission power, manually turns off the vacuum pump 6, the refrigerating system 7 and the valve 8-2, and turns on the defrosting valve 14 of the vacuum water capturing system 4 to allow air to enter the freeze drying bin 3.
When the pressure regulating system 5 is at normal pressure, the microwave bin gate 13-2 and the freeze-drying bin gate 13-1 are sequentially opened, the freeze-dried banana blocks are taken out, and the freeze-drying is finished. The moisture of the freeze-dried banana blocks was determined to be reduced to below 4%.
Examples
This example is a preferred embodiment of the present utility model and is specifically designed in the same manner as example 1 to freeze-dry a cellulose SiO2 composite aerogel material. The specific operation process is as follows:
the microwave bin gate 13-2 and the freeze-drying bin gate 13-1 are opened, and a plurality of cellulose SiO2 composite wet gels to be freeze-dried are respectively placed on the micro conveyor belt 16 on the turntable 12. The freeze-drying bin gate 13-1 and the microwave bin gate 13-2 are closed in sequence. The wet gel is a cube or sheet, spaced about 2cm apart from each other, and uniformly distributed on the micro conveyor 16.
The refrigeration system 7 and valves 8-1 and 8-2 are opened to freeze the wet gel on the turntable 12 and rapidly reduce the vacuum water capture temperature to-45 ℃.
The microcomputer central control system is programmed to automatically adjust parameters such as a change mode of microwave power, a change mode and a change amplitude of pressure, a relative change matching mode of pressure and microwave power, the rotating speed of a rotating disc, the moving frequency of a micro conveyor belt and the like in the freeze-drying process of wet gel.
When the hydrogel freezes, the valve 8-1 is closed, the vacuum pump 6 is turned on, and at the moment, the vacuum degree in the freeze-drying bin 3 is rapidly increased.
When the pressure regulation system 5 shows a pressure drop in a preset pressure range, for example 10-30Pa, the microcomputer central control system will activate the motor 10 and the micro conveyor 16 to start the movement of the frozen gel mass at a certain rate.
The microcomputer central control system starts a microwave generator 1 with continuously adjustable emission power, microwaves start to be collapsed into a freeze-drying bin 3, and the frozen gel blocks are heated.
As the heating proceeds, the water and other solvents in the frozen gel mass begin to sublimate, and the sublimated gas enters the vacuum water capturing system 4, so that the pressure in the freeze-drying bin 3 does not rise.
In the drying process, the microcomputer central control system can properly adjust and raise the pressure in the freeze-drying bin within the range of ensuring the pressure required by drying according to the pressure change displayed by the pressure adjusting system 5. Meanwhile, the microcomputer central control system automatically adjusts the rotating speed of the turntable and the movement frequency of the micro conveyor belt according to the change mode of microwave power, the change mode and the change amplitude of pressure and the relative change matching mode of pressure and microwave power.
As the power of the continuously adjustable microwave generator 1 is gradually reduced, the gel block drying is also nearly completed. When the pressure regulation system 5 shows no more changes in pressure, it is indicated that the wet gel has completely dried.
When the indication number of the pressure regulating system 5 is not changed any more within a certain time, the microcomputer central control system sequentially turns off the microwave generator 1, the motor 10 and the micro conveyor belt 16 with continuously adjustable emission power, manually turns off the vacuum pump 6, the refrigerating system 7 and the valve 8-2, and turns on the defrosting valve 14 of the vacuum water capturing system 4 to allow air to enter the freeze drying bin 3.
When the pressure regulating system 5 is at normal pressure, the microwave bin gate 13-2 and the freeze-drying bin gate 13-1 are sequentially opened, the freeze-dried aerogel is taken out, and the freeze-drying is finished. The moisture of the cellulose SiO2 composite aerogel is reduced to below 3 percent through measurement.
In summary, the present utility model has several advantages:
the freeze-drying bin is arranged in the microwave bin and is positioned at the center of the lower part, microwaves emitted by the microwave generator enter a normal pressure environment through the crumple inlet and then enter the freeze-drying bin in a vacuum state, and the discharge phenomenon cannot occur in the process.
2. The microwave generator with continuously adjustable transmitting power is applied, the program setting of the microcomputer central control system can control the change mode of microwave power under the condition of ensuring that the microwave frequency is certain, the field intensity in the freeze drying bin can be changed, and the pressure regulating system is utilized to properly improve the working pressure under the condition that the pressure is ensured to be in a normal range, so that the working pressure is always under the field intensity threshold value of glow discharge, and the discharge phenomenon can be avoided.
3. The microwave generator with continuously adjustable power is applied, the micro conveyor belt on the turntable and the power matching turntable of the microwave generator is continuously adjusted by the microcomputer central control system, so that the uniformity of microwave heating of materials is ensured, and the rotating speed of the turntable and the frequency of movement of the micro conveyor belt can be automatically adjusted by a program set by the central control system according to a pressure change mode and a change amplitude in the freeze drying bin and a relative change matching mode of pressure and microwave power. Moreover, as each material moves in two directions at the same time, the problem of uneven heating caused by fixed material positions or relative static materials and rotating discs is avoided.
4. The aerogel material can be dried thoroughly, and a novel method for drying the aerogel material is provided.
While the utility model has been described with reference to a specific embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the utility model. Therefore, it is intended that the utility model not be limited to the particular embodiment disclosed, but that the utility model will include all embodiments falling within the scope of the appended claims.
Claims (8)
1. A microwave vacuum freeze drying device comprises a microwave bin, a freeze drying bin, a microwave generator with continuously adjustable emission power, a refrigerating system, a vacuum water capturing system, a pressure regulating system, a vacuum pump and a microcomputer central control system,
it is characterized in that the method comprises the steps of,
the freeze-drying bin is arranged in the microwave bin, a turntable which is driven by a motor and can horizontally rotate is arranged at the bottom of the freeze-drying bin, a plurality of micro conveyor belts which can do reciprocating motion along the radial direction of the turntable are symmetrically arranged on the turntable,
the microwave generator with continuously adjustable transmitting power is fixed on the side wall of the microwave bin and evenly and crosswise arranged around the freeze-drying bin,
the refrigerating system is connected with the freeze-drying bin and the vacuum water catching system,
the vacuum water catching system is connected with the vacuum pump and the freeze-drying bin,
the pressure regulating system is connected with the vacuum pump and the freeze-drying bin,
the microcomputer central control system is respectively connected with the microwave generator and the pressure regulating system, controls the microwave generator and the pressure regulating system in a preset combined control mode so that the microwave power generated by the microwave generator corresponds to the pressure regulated by the pressure regulating system, is respectively connected with the turntable and the micro conveyor belt, regulates the rotating speed of the turntable according to the microwave power and the pressure regulated by the combined control mode,
the rotary table can horizontally rotate, the part passing through the microwave bin between the rotary table and the motor is connected by using a metal shielding overflow plate with a mesh with a specified size, and a sealing gasket is arranged at the position passing through the freeze-drying bin.
2. The microwave vacuum freeze drying apparatus of claim 1, wherein the microwave bin is made of a metallic wave-impermeable material and the freeze-drying bin is made of a non-metallic wave-transparent material and sized in a predetermined proportion to the microwave bin.
3. The microwave vacuum freeze drying apparatus according to claim 1, wherein the refrigerating system is connected with the freeze drying bin and the vacuum water catching system through a pipeline, a valve is arranged in the pipeline, the opening and closing between the refrigerating system and the freeze drying bin and between the refrigerating system and the vacuum water catching system are controlled through the valve, and the pipeline between the refrigerating system and the microwave bin is connected by a metal shielding overflow plate with specified-size sieve holes.
4. The microwave vacuum freeze drying equipment according to claim 1, wherein the vacuum water capturing system is connected with the vacuum pump, the pressure regulating system and the freeze drying bin through pipelines, the pipelines between the vacuum water capturing system and the microwave bin are connected by metal shielding overflow plates with holes with specified sizes, the pipelines are connected with the freeze drying bin through metal shielding overflow plates with holes with specified sizes, and a defrosting valve is arranged at the lower part of the vacuum water capturing system.
5. The microwave vacuum freeze-drying apparatus according to claim 1, wherein the microwave generator whose transmission power is continuously adjustable keeps the frequency of the transmitted microwaves constant while realizing the continuous adjustment of the transmission power.
6. A material drying method is characterized in that a microwave vacuum freeze drying device is used for drying, the microwave vacuum freeze drying device comprises a microwave bin, a freeze drying bin, a microwave generator with continuously adjustable emission power, a refrigerating system, a vacuum water capturing system, a pressure regulating system, a vacuum pump and a microcomputer central control system, the freeze drying bin is arranged in the microwave bin, a turntable which is driven by a motor and can horizontally rotate is arranged at the bottom of the freeze drying bin, a plurality of micro-conveyor belts which can reciprocate along the radial direction of the turntable are symmetrically arranged on the turntable,
the microwave generator with continuously adjustable transmitting power is fixed on the side wall of the microwave bin and evenly and crosswise arranged around the freeze-drying bin,
the refrigerating system is connected with the freeze-drying bin and the vacuum water catching system,
the vacuum water catching system is connected with the vacuum pump and the freeze-drying bin,
the pressure regulating system is connected with the vacuum pump and the freeze-drying bin,
the drying method of the material comprises the following steps:
1) Placing the wet material in the lyophilization chamber;
2) Freezing the wet material; and
3) The micro-computer central control system controls the microwave generator to generate microwaves and the pressure regulating system to regulate the pressure, the rotating speed of the turntable and the transmission frequency of the micro conveyor belt in a combined control mode, the micro-computer central control system controls the microwave generator and the pressure regulating system in a preset combined control mode so that the microwave power generated by the microwave generator corresponds to the pressure regulated by the pressure regulating system, and the micro-computer central control system regulates the rotating speed of the turntable according to the microwave power and the pressure regulated by the combined control mode so as to heat the material to dry the material and obtain the freeze-dried material.
7. The method of drying a material according to claim 6, wherein the material is an aerogel material.
8. The method of drying a material according to claim 7, wherein the aerogel material is cellulose SiO 2 Composite aerogel.
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| CN108433136B (en) * | 2017-11-15 | 2020-11-06 | 中国包装和食品机械有限公司 | Ultrasonic wave is microwave rapid draing system in coordination |
| CN108106373B (en) * | 2018-01-02 | 2020-10-23 | 济南大学 | Use method of microwave vacuum freeze drying device |
| CN111578648B (en) * | 2019-02-19 | 2022-12-23 | 江苏食品药品职业技术学院 | Microwave heating type vacuum freeze dryer with multiple oscillation modes |
| CN114144388A (en) * | 2019-07-22 | 2022-03-04 | 克罗斯林克私人有限公司 | Systems and methods for manufacturing water-based hydrophobic aerogels and aerogel composites |
| CN113758158B (en) * | 2021-09-24 | 2022-05-17 | 四川大学 | Microwave vacuum freeze-drying device |
| DE102022124044A1 (en) | 2022-09-20 | 2024-03-21 | Püschner GmbH & Co. Kommanditgesellschaft | Method and device for vacuum drying of products, in particular membrane filters, such as dialyzers, in particular after washing or a functional test, using microwave energy |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1800722A (en) * | 2005-01-04 | 2006-07-12 | Lg电子株式会社 | Turntable device of microwave oven |
| CN201233162Y (en) * | 2008-05-01 | 2009-05-06 | 天水华圆制药设备科技有限责任公司 | Microwave freeze drier |
| CN101438730A (en) * | 2008-12-23 | 2009-05-27 | 中国农业机械化科学研究院 | Method for preparing dry red date and red date produced thereby |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9267734B2 (en) * | 2012-12-07 | 2016-02-23 | Enwave Corporation | Microwave vacuum-drying of organic materials |
| CN105651017B (en) * | 2016-03-18 | 2017-11-24 | 农业部南京农业机械化研究所 | A kind of multifunction microwave deep fat combination freeze drying equipment and its control method |
| CN206905412U (en) * | 2017-03-17 | 2018-01-19 | 澍澎（北京）新材料科技有限公司 | Microwave vacuum freeze-drying device |
-
2017
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1800722A (en) * | 2005-01-04 | 2006-07-12 | Lg电子株式会社 | Turntable device of microwave oven |
| CN201233162Y (en) * | 2008-05-01 | 2009-05-06 | 天水华圆制药设备科技有限责任公司 | Microwave freeze drier |
| CN101438730A (en) * | 2008-12-23 | 2009-05-27 | 中国农业机械化科学研究院 | Method for preparing dry red date and red date produced thereby |
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