Screening device and method for sine microwaves

Abstract

The invention relates to the technical field of microwave heating, in particular to a sine microwave screening device and method. The sine microwave screening device comprises a drying cavity, a wave shaping mechanism with the specified wavelength and a waveguide mechanism for effectively managing output energy of the wave shaping mechanism are installed on the drying cavity, the waveguide mechanism comprises a plurality of waveguide holes installed in the drying cavity, the waveguide holes are symmetrically formed in the inner wall of the drying cavity, and the waveguide holes are communicated with the drying cavity. Therefore, the sine microwaves are used for efficiently heating the to-be-dried product in the drying cavity, effective utilization of a heat source is achieved, and energy waste is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of microwave heating, and in particular to a sinusoidal microwave screening device and method. Background Art

[0002] Microwaves are a type of electromagnetic wave with a wavelength between 1mm and 1000mm. They have the dual nature of wave and particle, and their basic properties are usually three characteristics: penetration, reflection, and absorption. For glass, plastic, porcelain, etc., microwaves almost pass through without being absorbed; for certain substances containing water, such as food, microwaves are absorbed; for metals, such as stainless steel, iron, aluminum, etc., microwaves are reflected. Microwaves of different wavelengths will produce different effects, such as thermal effects, heating, sterilization, etc., and these different effects are used in different daily applications.

[0003] From the perspective of the development of modern microwave technology, it is generally believed that electromagnetic waves with a wavelength of ≤3mm (i.e., millimeter waves above 100GHz) belong to the microwave range. From the perspective of energy, the shorter the wavelength, the higher the frequency, and the greater the energy. The water molecules contained in the heated material are polar molecules. Under the action of a rapidly changing high-frequency electromagnetic field (microwave), their polar orientation will change with the change of the external electric field. This causes the spin motion of the water molecules. At this time, the field energy of the microwave field is converted into thermal energy in the medium, which increases the temperature of the material, produces a series of physical and chemical processes such as thermalization, and achieves the purpose of microwave heating and drying. The energy of electromagnetic waves with a frequency of less than 300MHz is too small. Only the energy provided by electromagnetic waves from 300MHz to 300GHz has heating application value.

[0004] The freeze-drying process is all about sublimation reaction, which is an extremely slow reaction process. For example, the sublimation reaction of drugs in pharmaceutical processes generally takes 7 to 21 days. The main reason is that the sublimation reaction of freeze-drying is completed in a vacuum environment. The existing heating methods in a vacuum environment are as follows:

[0005] 1) Electric heating wire heating: The electric heating wire is installed at the bottom of the metal heat conductive plate, and the container of the product (material) is placed on the metal heat conductive plate. When the electric heating wire is energized, the metal heat conductive plate is heated, and the heat is transferred to the container, and then to the product (material) to provide energy.

[0006] 2) Thermal oil heating: Make a hollow metal heat-conducting plate, inject heat-conducting oil into the heat-conducting plate, heat the heat-conducting oil to heat the heat-conducting plate, transfer the heat to the container, and then transfer it to the product (material) to provide energy.

[0007] 3) Others such as radiation heating, light heating, etc.

[0008] In the above methods, heating wire heating and thermal oil heating are both indirect heating. Figure 1As shown. Even if a higher power heating source can be used for this indirect heating, the energy loss in the transmission process is large (the conversion rate is low, about 10% to 20%), and the actual energy provided to the product (material) is low. Radiant heat and light heating directly heat the product (material), but the heating source of these two methods is too low, such as absorbing radiant heat from natural light. Therefore, it is urgent to provide a heating method with high heating efficiency and high heat source utilization, using sinusoidal microwaves for heating. Sinusoidal microwaves can be regarded as a regular wave, and its function is to ensure the uniform distribution of microwave energy in a regular space of a certain volume. However, there are currently no reports on related sinusoidal microwave screening technology. Summary of the invention

[0009] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a sinusoidal microwave screening device and method.

[0010] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a sinusoidal microwave screening device, comprising a drying chamber, on which is installed a wave-straightening mechanism of a specified wavelength and a waveguide mechanism for effectively managing the output energy of the wave-straightening mechanism, wherein the waveguide mechanism is a plurality of waveguide holes installed in the drying chamber, and the waveguide holes are symmetrically arranged on the inner wall of the drying chamber.

[0011] Furthermore, the wave-rectifying device is a resonant waveguide of a single magnetron.

[0012] Furthermore, the power of a single magnetron is 1000W.

[0013] Furthermore, the resonant waveguide is installed at the upper rear position of the drying chamber.

[0014] Furthermore, the waveguide hole is a single-wavelength waveguide hole.

[0015] Furthermore, the waveguide holes include 18 holes, and the 18 waveguide holes are symmetrically arranged on the left and right sides of the drying chamber.

[0016] Furthermore, the distance between the waveguide holes arranged symmetrically is 2(2) 0.5 *N times the wavelength.

[0017] Furthermore, three adjacent waveguide holes on the same side are connected to each other, and the angle of their intersection lines is 60°.

[0018] A sinusoidal microwave screening method, using the above-mentioned sinusoidal microwave screening device, the method is as follows:

[0019] S1. Place the product to be dried in the drying chamber, start the wave source, and emit microwaves to heat the product to be dried;

[0020] S2, after microwaves enter the band screening device, the 1 / 4 wavelength peak part is sliced ​​and reflected back, and the 1 / 4 wavelength valley part is sliced ​​and absorbed;

[0021] S3. The reflected 1 / 4 wavelength peaks intersect with each other through the waveguide hole to achieve maximum energy, thereby heating the product to be dried.

[0022] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0023] The present application controls the wavelength output frequency through a wave-rectifying mechanism of a specified wavelength, and effectively manages the output energy of the magnetron through a waveguide mechanism, thereby realizing efficient heating of the product to be dried in the drying chamber using sinusoidal microwaves, achieving effective utilization of heat sources, and avoiding energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of a sinusoidal microwave screening device in a preferred embodiment of the present invention;

[0025] Figure 2 This is a cross-sectional distribution diagram exported by the infrared thermal imaging sensor analysis software;

[0026] Figure 3 The microwave thermal images of the screening device with and without sinusoidal microwaves;

[0027] Figure 4 This is a diagram of microwave energy distribution.

[0028] Figure numerals: 1. Drying cavity; 2. Waveguide hole; 3. Harmonic waveguide. DETAILED DESCRIPTION

[0029] The technical solutions in the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] Reference Figure 1 As shown, a preferred embodiment of the present invention is a sinusoidal microwave screening device, comprising a drying chamber 1, on which is installed a wave-straightening mechanism of a specified wavelength and a waveguide mechanism for effectively managing the output energy of the wave-straightening mechanism, the waveguide mechanism is a plurality of waveguide holes 2 installed in the drying chamber 1, and the waveguide holes 2 are symmetrically arranged on the inner wall of the drying chamber 1, so as to realize efficient heating of the product to be dried in the drying chamber by using sinusoidal microwaves, realize effective utilization of heat sources, and avoid energy waste.

[0031] As a preferred embodiment of the present invention, it may also have the following additional technical features: the wave-rectifying device is a 1000W single magnetron resonant harmonic waveguide 3, and the resonant harmonic waveguide 3 is installed at the upper rear position of the drying chamber to provide microwave energy for the screening device.

[0032] In this embodiment, the waveguide hole 2 is a single-wavelength waveguide hole. The waveguide holes 2 include 18 holes. The 18 waveguide holes are symmetrically arranged on the left and right sides of the drying chamber, and the distance between the waveguide holes 2 symmetrically arranged on the left and right sides is 2 (2). 0.5 *N times the wavelength. For example, if a wavelength of 1mm is selected, the distance of the waveguide holes can be set to N×2.828mm. In this way, the microwaves can cross-propagate in the waveguide holes, and the peaks intersect with each other, thus obtaining sinusoidal microwaves.

[0033] In this embodiment, three adjacent waveguide holes 2 on the same side are connected to each other, and the angle of their intersection lines is 60°, so that the wave crests can intersect with each other, maximizing energy utilization and providing energy for the water-containing product (material).

[0034] A sinusoidal microwave screening method, using the above-mentioned sinusoidal microwave screening device, the method is as follows:

[0035] S1. Place the product to be dried in the drying chamber, start the wave source, and emit microwaves to heat the product to be dried;

[0036] S2, after microwaves enter the band screening device, the 1 / 4 wavelength peak part is sliced ​​and reflected back, and the 1 / 4 wavelength valley part is sliced ​​and absorbed;

[0037] S3. The reflected 1 / 4 wavelength peaks and 1 / 4 wavelength peaks intersect to achieve maximum energy through the waveguide hole, and heat the product to be dried. The product to be dried in the drying chamber can be efficiently heated by sinusoidal microwaves, which effectively utilizes the heat source and avoids energy waste.

[0038] The following is a description of the specific embodiments.

[0039] Comparative Example

[0040] A 1kW microwave with a wavelength of 2450nm was used to heat a 400×550×300mmH stainless steel cavity and 2kG of water in the cavity. The PID temperature was adjusted between 60℃ and 100℃. An infrared thermal imaging sensor was installed on the top of the cavity, and a container containing water was placed on the mass sensor. The microwave heating observation experiment was started.

[0041]

[0042] Note: PID adjustment is not accurate before 60℃ and is not taken into account. The action time is set to 5 minutes at 100℃, and the mass sensor value is displayed as 0 in about 20 seconds.

[0043] From the table above, we can see that even if the temperature does not reach the boiling point, the water mass has already decreased. Microwaves not only heat the container and its surrounding environment, but also when the solvent of the product (material) is water, water has polarity and can absorb microwaves. Microwaves can heat the product (material) placed in it (called "direct heating"), and can also heat the container and the environment (called "indirect heating"). If the solvent of the product (material) is a polar substance, such as water, it can absorb microwaves to speed up the reaction.

[0044] Example

[0045] Within a certain N wavelength distance, screening out continuous sinusoidal microwaves can greatly improve the energy conversion rate. Screening out sinusoidal microwaves with high energy conversion rates can be used to provide energy for water-containing products (materials). This method can greatly improve production efficiency under the same products (materials) and production conditions. See the test data in the table below.

[0046]

[0047] It can be seen from the comparative examples and embodiments that:

[0048] 1. Use infrared thermal imaging sensor analysis software to export the cross-sectional distribution diagram, such as Figure 2 As shown. For the reaction of products (materials) or water-containing products, microwave thermal effect method can replace other existing heating methods to provide greater energy and significantly reduce the reaction time.

[0049] 2. Microwave thermal efficiency has its uncertainties, such as Figure 2 As shown. Through the temperature test analysis on the horizontal section (thermal imaging method of analog quantity test), the situation in the longitudinal direction is basically the same, as shown in Figure 3 As shown on the left, a band screening device is installed on the reflection wall. After the microwave enters the band screening device, it will not be directly reflected back in disorder, but the 1 / 4 wavelength peak will be partially sliced ​​and reflected back, and the 1 / 4 wavelength valley will be partially sliced ​​and absorbed. At the same time, the reflected 1 / 4 wavelength peak and 1 / 4 wavelength peak are arranged in a physical way through the hole position limit, so that the total energy of the reflected peak reaches the maximum. This is because the energy is maximum when the microwave peaks intersect, and the energy is minimum when the troughs intersect, such as Figure 4 Therefore, although microwave energy can effectively provide sublimation energy, its conversion rate is still very low, about 30%, if a band screening device is not installed.

[0050] Therefore, the present application installs a sinusoidal microwave screening device in the drying chamber so that the wave peaks intersect with each other, thereby maximizing the microwave energy conversion rate, thereby achieving effective energy utilization and avoiding energy waste.

[0051] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0052] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A sinusoidal microwave screening device, characterized in that: The invention comprises a drying chamber, on which a wave-straightening mechanism of a specified wavelength and a waveguide mechanism for effectively managing the output energy of the wave-straightening mechanism are installed. The waveguide mechanism is a plurality of waveguide holes installed in the drying chamber, and the waveguide holes are symmetrically arranged on the inner wall of the drying chamber.

2. The sinusoidal microwave screening device according to claim 1, characterized in that: The wave-rectifying device is a resonant waveguide of a single magnetron.

3. The sinusoidal microwave screening device according to claim 2, characterized in that: The power of the single magnetron is 1000W.

4. The sinusoidal microwave screening device according to claim 2, characterized in that: The resonant waveguide is installed at the upper rear position of the drying chamber.

5. The sinusoidal microwave screening device according to claim 1, characterized in that: The waveguide hole is a single-wavelength waveguide hole.

6. The sinusoidal microwave screening device according to claim 5, characterized in that: The waveguide holes include 18 in number, and the 18 waveguide holes are symmetrically arranged on the left and right sides of the drying chamber.

7. The sinusoidal microwave screening device according to claim 6, characterized in that: The distance between the waveguide holes arranged symmetrically on both sides is 2(2) 0.5 *N times the wavelength.

8. The sinusoidal microwave screening device according to claim 6, characterized in that: Every three adjacent waveguide holes on the same side are connected to each other, and the angle of their intersection lines is 60°.

9. A method for screening sinusoidal microwaves, characterized in that: The screening device using the sinusoidal microwaves described in any one of claims 1 to 8 is as follows: S1. Place the product to be dried in the drying chamber, start the wave source, and emit microwaves to heat the product to be dried; S2, after microwaves enter the band screening device, the 1 / 4 wavelength peak part is sliced ​​and reflected back, and the 1 / 4 wavelength valley part is sliced ​​and absorbed; S3. The reflected 1 / 4 wavelength peaks intersect with each other through the waveguide hole to achieve maximum energy, thereby heating the product to be dried.

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