Background
Microwave is a high-frequency electromagnetic wave, and is widely applied to various fields such as communication, kitchen appliances, scientific instruments and the like, and the principle of microwave heating is as follows: when the material is in the microwave field, the polar molecules in the material rub along with the periodic change of the polarity of the alternating electromagnetic field, and the energy of the microwave field is converted into heat energy. The microwave heating technology mainly includes microwave oven, which is composed of power supply, magnetron, resonant cavity and other parts, the power supply provides high voltage to the magnetron, the magnetron is excited by the power supply to continuously generate microwave, and then the microwave is coupled into the resonant cavity through waveguide system, a rotatable tray is arranged at the bottom of the resonant cavity, when heating, the material to be heated is loaded by non-metal vessel and then placed on the tray, the tray is rotated to make microwave energy uniformly distributed on the material, thereby heating the material. The microwave digestion instrument is characterized in that the microwave digestion instrument is a novel technology of microwave digestion instrument which is formed by arranging one or more digestion tanks on a tray of a microwave oven heating cavity, the tray can heat materials in the digestion tanks by rotating, but the microwave digestion instrument has limitations, the microwave digestion instrument is designed for heating large-volume materials, digestion is carried out simultaneously by a plurality of samples, the efficiency of batch digestion is improved, and more, a plurality of digestion tanks are matched, the microwave digestion instrument is only used in a laboratory at present, and can only be used as an independent heating device, and is difficult to be integrated into an on-line analysis system of an industrial field as a module, in addition, the microwave digestion instrument has small intensity in a huge resonant cavity microwave field, and the problem of relatively low heating and warming speed can occur.
Disclosure of Invention
The invention aims to provide an industrial field online microwave heating device aiming at the defects of the prior art, which can be integrated into an industrial field online analysis system as a module, can realize the rapid heating of materials through the simultaneous action of a high-intensity magnetic field and a high-intensity electric field formed in the device, and improves the heating speed of the materials.
The technical scheme of the invention is as follows: an industrial field online microwave heating device comprises an excitation cavity shell and a resonant cavity shell, wherein a resonant window is fixedly connected between the excitation cavity shell and the resonant cavity shell, the waveguide structures of an excitation cavity in the excitation cavity shell and a resonant cavity in the resonant cavity shell are the same, the excitation cavity is communicated with the resonant cavity through a microwave passing window arranged on the resonant window, a through hole which is vertically intersected with the axis of the microwave passing window is arranged on the resonant window and used for a material pipe to pass through, a movable tuning plate is arranged in the excitation cavity and fixedly connected with a push-pull rod, the push-pull rod is in sliding fit with the excitation cavity shell and extends out of the excitation cavity shell, a magnetron is installed at the upper end of the excitation cavity shell, and an energy output head of the magnetron extends into the excitation cavity and is positioned between the tuning plate and the resonant window.
The excitation cavity and the resonant cavity are both rectangular waveguides with rectangular sections, and the resonant window is rectangular in section, or the excitation cavity and the resonant cavity are both circular waveguides with circular sections, and the resonant window is circular in section.
The lengths of the excitation cavity and the resonant cavity are integral multiples of 0.5 time of the guided wave wavelength.
The excitation cavity and the resonant cavity both adopt BJ32 rectangular waveguides.
The distance between the energy output head of the magnetron and the resonant window is integral multiple of 1/4 guided wave wavelengths.
The resonant window is fixed with the excitation cavity shell and the resonant cavity shell through welding.
The material pipe adopts the non-metal pipe, the both ends of material pipe are used for connecting the material pipeline of industrial field.
And an adjusting gasket is arranged between the magnetron and the outer wall of the excitation cavity shell.
And a hole for mounting a sensing element is formed in the resonant window.
The magnetron 1 adopts a 2450MHz water-cooled magnetron with the power of 1000 watts.
Adopt above-mentioned technical scheme: an industrial field online microwave heating device comprises an excitation cavity shell and a resonant cavity shell, wherein a resonant window is fixedly connected between the excitation cavity shell and the resonant cavity shell, the waveguide structures of an excitation cavity in the excitation cavity shell and a resonant cavity in the resonant cavity shell are the same, the excitation cavity is communicated with the resonant cavity through a microwave passing window arranged on the resonant window, a through hole which is vertically intersected with the axis of the microwave passing window is arranged on the resonant window and used for a material pipe to pass through, a movable tuning plate is arranged in the excitation cavity and fixedly connected with a push-pull rod, the push-pull rod is in sliding fit with the excitation cavity shell and extends out of the excitation cavity shell, a magnetron is installed at the upper end of the excitation cavity shell, and an energy output head of the magnetron extends into the excitation cavity and is positioned between the tuning plate and the resonant window. When the heating device works in a heating mode, the energy output head of the magnetron excites an electromagnetic field in an excitation cavity, the electromagnetic field of the excitation cavity is coupled into the resonance cavity in a mode of electromagnetic diffraction by adjusting the tuning plate and replacing gaskets with different thicknesses, super-strong electromagnetic field distribution is formed, impedance matching is realized through microwave transmission at the moment, strong magnetic field and strong electric field distribution are formed in a window area of microwave passing of the resonance window, and the material in the material pipe is rapidly heated by utilizing the simultaneous action of the magnetic field and the electric field.
The excitation cavity and the resonant cavity are both rectangular waveguides with rectangular sections, and the resonant window is rectangular in section, or the excitation cavity and the resonant cavity are both circular waveguides with circular sections, and the resonant window is circular in section. The shape of the resonance window can be matched according to the excitation cavity and the resonance cavity, and flexible arrangement is facilitated.
The lengths of the excitation cavity and the resonant cavity are integral multiples of 0.5 time of the guided wave wavelength, so that impedance matching can be easily realized in microwave transmission, and microwave energy can be better utilized.
The excitation cavity and the resonant cavity both adopt BJ32 rectangular waveguides, which is convenient for transmitting 2450MHz microwave.
The distance between the energy output head of the magnetron and the resonant window is integral multiple of the wavelength of 1/4 guided waves, so that the microwave transmission is adjusted conveniently to realize impedance matching, and the microwave energy efficiency is maximized.
The resonant window is fixed with the excitation cavity shell and the resonant cavity shell through welding, so that the firmness and the tightness of the device are improved, and the transmission efficiency of microwaves is improved.
The material pipe adopts the non-metal pipe, the both ends of material pipe are used for connecting the material pipeline of industrial field, make things convenient for the device to integrate in the on-line analysis system of industrial field.
An adjusting gasket is arranged between the magnetron and the outer wall of the excitation cavity shell, and the adjusting gasket can change the depth of the energy output head of the magnetron inserted into the excitation cavity shell, so that the transmission of microwave energy and the working state of the magnetron can be conveniently adjusted.
The resonance window is provided with a hole for installing a sensing element, the sensing element can be installed, and the heating and temperature rising state in the material pipe can be monitored conveniently.
The magnetron adopts a 2450MHz water-cooled magnetron with the power of 1000W, the emitted microwave wavelength is shorter, the microwave energy is easier to concentrate, the water cooling is convenient for rapidly cooling the magnetron, and the normal work of the magnetron is ensured.
The industrial field on-line microwave heating device is simple in structure, small in size and convenient to operate, can be integrated into an industrial field on-line analysis system as a module, and can realize rapid heating of materials in the material pipe through the simultaneous action of a high-intensity magnetic field and a high-intensity electric field formed in the device, so that the heating efficiency of microwaves is improved.
The invention is further described with reference to the drawings and the specific embodiments in the following description.
Detailed Description
Referring to fig. 1 to 4, an industrial field online microwave heating device comprises an excitation cavity shell 2 and a resonant cavity shell 6, wherein one end of the excitation cavity shell 2 is open, the other end of the excitation cavity shell 2 is closed, a resonant window 5 is welded and fixed between the excitation cavity shell 2 and the resonant cavity shell 6, the excitation cavity 2-1 in the excitation cavity shell 2 and the resonant cavity 6-1 in the resonant cavity shell 6 have the same waveguide structure, both rectangular waveguides or circular waveguides can be adopted, a BJ32 rectangular waveguide is the best waveguide, and the lengths of the excitation cavity 2-1 and the resonant cavity 6-1 are integral multiples of 0.5 times of guided wave wavelength, so that microwave energy can be better utilized. The shape of the resonant window 5 can be set according to the shapes of the excitation cavity 2 and the resonant cavity 6, when the excitation cavity 2-1 and the resonant cavity 6-1 are both rectangular waveguides, the cross section of the resonant window 5 is rectangular, or when the excitation cavity 2-1 and the resonant cavity 6-1 are both circular waveguides with circular cross sections, the cross section of the resonant window 5 is circular. The excitation cavity 2-1 is communicated with the resonant cavity 6-1 through a microwave passing window 5-1 arranged on the resonant window 5, the shape of the window 5-1 can be any shape such as a circle, a rectangle and an irregular figure, a through hole 5-2 vertically intersected with the axis of the microwave passing window 5-1 is arranged on the resonant window 5, the through hole 5-2 is used for a material pipe 5-4 to pass through, the material pipe 5-4 adopts a non-metal pipe, two ends of the material pipe 5-4 are provided with quick connectors for connecting a material conveying pipeline of an industrial field, and the device is conveniently integrated into an online analysis system of the industrial field. The resonant window 5 is provided with a hole 5-3 for installing a sensing element so as to monitor the heating state in the material pipe 5-4. A movable tuning plate 3 is arranged in the excitation cavity 2, the tuning plate 3 is fixedly connected with a push-pull rod 3-1, the push-pull rod 3-1 is in sliding fit with the excitation chamber housing 2 and extends out of the excitation chamber housing 2, a 2450MHz water-cooled magnetron 1 is arranged on the outer wall of the upper end of the excitation cavity shell 2, the working power is 1000 watts, the energy output head of the magnetron 1 extends into the excitation cavity 2-1, and is positioned between the tuning plate 3 and the resonant window 5, the energy output head of the magnetron 1 is spaced from the resonant window 5 by an integral multiple of 1/4 guided wave wavelengths, an adjusting gasket 4 is arranged between the magnetron 1 and the outer wall of the excitation cavity shell 2, and the adjusting gasket 4 can change the depth of the energy output head of the magnetron 1 inserted into the excitation cavity shell 2, so that the transmission of microwave energy and the working state of the magnetron can be conveniently adjusted.
When the industrial field on-line microwave heating device carries out microwave heating, two ends of a material pipe 5-4 in a through hole 5-2 of a resonant window 5 are connected with a material conveying pipeline of an industrial field, so that liquid materials to be heated flow into the material pipe 5-4, then a magnetron power supply is started to supply power to a magnetron 1, the magnetron power supply provides 4.4kv of anode voltage, 0.32A of anode current and 3.15 v of filament current for the magnetron 1, the magnetron 1 works in a pi mode, a TEM mode microwave field is generated in an energy output head of the magnetron 1, a TE mode or TM mode electromagnetic field is excited in an excitation cavity 2, then a tuning plate 3 is adjusted and gaskets 4 with different thicknesses are replaced, when the measured value of the electrical parameters of the magnetron 1 is matched with or close to a working characteristic curve provided by a magnetron manufacturer, the TE mode electromagnetic field of the excitation cavity 2 is coupled to a resonant cavity 6 by bypassing the resonant window 5 in an electromagnetic diffraction mode, and strong magnetic field and strong electric field distribution are formed in the through hole 5-3 area of the resonant window 5, so that the strong magnetic field and the strong electric field jointly act on the material pipe 5-4, and the material in the material pipe 5-4 is rapidly heated.