Side output type radio frequency resonance generator and insecticidal sterilization deviceTechnical Field
The invention relates to the field of disinsection and sterilization, in particular to a side output type radio frequency resonance generator and a disinsection and sterilization device.
Background
The radio frequency is a high-frequency alternating current electromagnetic wave with the frequency range of 3-300 MHz. The radio frequency bands allowed for use in the industry are 13.56,27.12 and 40.68MHz. The frequency is relatively low compared with microwaves, so that the material has a deeper penetrating effect. Under the action of the high-frequency magnetic field of radio frequency, polar molecules rotate reciprocally, and charged ions move reciprocally, so that the polar molecules and the charged ions in the nonmetallic materials (agricultural products) placed in the high-frequency electromagnetic field rub with surrounding molecules to generate heat, and the water-containing sample is heated in the whole volume simultaneously, so that the temperature rising rate of the sample is accelerated. The agricultural products are selectively heated by utilizing the principle of different dielectric loss factors, so that the purposes of insect killing and sterilization are achieved. The heating is carried out by adopting a radio frequency mode, the medium is heated uniformly and rapidly, and the heating has the characteristic of selective heating, so that the radio frequency heating is an ideal and effective cold heating means. In the field of crop (or food) disinsection and sterilization, pests and bacteria are selectively and rapidly heated, the protein structure of the pests and the bacteria is destroyed, the effect of killing the pests and the bacteria is achieved, and the crop (or food) has smaller heating, not only preserves nutrient components, but also has good mouthfeel, thus having very bright application prospect.
The traditional technology has the following technical problems:
the lumped parameter LC resonant circuit frequency is easy to shift, which causes interference to nearby wireless devices, and requires to select circuit components with higher price and better electrical characteristics, thereby increasing the cost of the devices. In addition, the centralized parameter element is easy to age and has the problems of electrical property reduction and the like in a high-frequency and high-voltage working environment, so that the whole device is unstable in work, low in working efficiency, potential safety hazards and the like are caused.
Disclosure of Invention
The invention aims to solve the technical problem of providing a side output type radio frequency resonance generator and an insecticidal sterilization device.
In order to solve the above technical problems, the present invention provides a side output type radio frequency resonance generator, comprising: a high frequency resonant cavity and a vacuum electron tube box; the vacuum electron tube box is formed by fixing and sealing a vacuum electron tube through an insulating support and an insulating plate, and is positioned in the center of the high-frequency resonant cavity; the high-frequency resonant cavity comprises a box metal shell, a resonant cavity output polar plate, a resonant adjusting capacitor polar plate and an output coupling polar plate; the output polar plate of the resonant cavity is of a cuboid box structure without a bottom surface; the resonance adjusting capacitor polar plate is positioned between the resonance output polar plate of the inner side surface of the high-frequency resonant cavity and the vacuum electron tube box; the output coupling polar plate is fixed on the right side in the high-frequency resonant cavity by the insulating base, and is led out from the side surface of the box body through the output transition polar plate and the output soft copper foil to be connected with the load polar plate.
The invention has the beneficial effects that:
the distributed resonant circuit formed by adopting the distribution parameters of the fully-closed box structure has the advantages of simple circuit structure, convenient adjustment, high stability of the oscillating frequency, low cost, long service life and the like. With a fairly high frequency stability, the oscillation frequency can be stabilized within + -0.8% of the center frequency.
In one embodiment, in the high-frequency resonant cavity, a resonant output polar plate is reversely buckled on the vacuum electron tube box and is fixed with the top of the vacuum electron tube box by a screw, and gaps exist between the outer surface of the resonant output polar plate, the inner surface of the metal shell of the box body and the high-frequency resonant cavity to form an air capacitor; meanwhile, the distributed inductance existing in the vacuum electron tube box body forms a main inductance of the resonance circuit; the inductor and the capacitor are connected in parallel to form a distributed resonant circuit with distributed parameters, and the distributed resonant circuit is used as a main loop of vacuum electron tube radio frequency oscillation.
In one embodiment, the inductance of the output polar plate of the resonant cavity is coupled with the inductance of the output coupling polar plate to form a coupling transformer, so that the feeding of radio frequency energy is realized.
In one embodiment, the output coupling polar plate is supported by an insulating base, one end of the output coupling polar plate is used for feeding radio frequency power to the radio frequency insecticidal sterilization treatment polar plate, and the other end of the output coupling polar plate is led out from the bottom of the box body to the upper part of the box body and returns to the grid electrode of the vacuum electron tube to serve as feedback control.
In one embodiment, the position of the output coupling polar plate is configured to change the coupling ratio by moving up and down to realize output load matching, and the adjusting device reaches the maximum power output.
In one embodiment, the resonant tuning capacitor plate is configured to be trimmed to the left and right to change capacitance.
In one embodiment, the box metal housing is integrally grounded.
In one embodiment, a forced air cooling device is arranged outside the metal shell of the box body, and the forced air cooling device is used for cooling the vacuum electron tube and the radio frequency resonance box body.
The insecticidal sterilization device comprises the side output high-frequency resonance radio frequency generator, and further comprises a power input part, a high-voltage rectification part, a control part and a load matching output part.
In one embodiment, the load matching output section is integrated within the high frequency resonant cavity.
Drawings
Fig. 1 is a main structural diagram of a radio frequency resonance insecticidal sterilization device. The power supply comprises a power input part, a high-voltage rectifying part, a parameter-distributed radio frequency resonance generator part, a load output part and a control part, wherein the power input part, the high-voltage rectifying part, the parameter-distributed radio frequency resonance generator part, the load output part and the control part are arranged in sequence.
Fig. 2 is a lumped parameter equivalent circuit diagram of the side output type radio frequency resonance generator.
Fig. 3 is a schematic structural equivalent diagram of the side output type rf resonant generator. The high-frequency resonant cavity comprises a high-frequency resonant cavity 6, a vacuum electron tube box body 7, a box body 8, a metal shell of the high-frequency resonant cavity 9, a perforated capacitor, a filament choke coil 10, a grid feedback adjustment inductance 11, a grid high-frequency choke coil 12, a perforated capacitor 13, a ceramic capacitor 14, a ceramic capacitor 15, a resonant cavity output polar plate 16, a resonant adjustment capacitance polar plate 17, a vacuum electron tube 18, an anode choke coil 19, an insulating support column 20 and an insulating plate 21, an output coupling polar plate 22, an output polar plate connected with a transition plate 23, an output polar mounting base 24 and a load capacitance polar plate.
Fig. 4 is a schematic top view of the structure of the side output type rf resonant generator. The output electrode plate 25, the output electrode plate 26, the soft copper foil 27, the output transition electrode 28, the output electrode plate of the resonant cavity 29, the resonant cavity inner box 30, the high-voltage capacitor of the resonant cavity 31, the anode connecting plate of the vacuum electron tube, and the anode connecting plate of the vacuum electron tube 32.
Fig. 5 is a front view of the structure principle of the side output type rf resonant generator. The device comprises a resonant cavity inner box sealing plate 33, a vacuum electron tube 34, a vacuum electron tube anode 35, a mounting base, a vacuum electron tube anode base support body 36, a resonant adjusting capacitor polar plate 37, an output polar mounting base 38, an output coupling polar plate 39 and a transition plate 40.
Fig. 6 is a schematic diagram of an output circuit of the rf insecticidal sterilization system. 41. 42 is the chamber load capacitance plate and 43 is the material to be processed.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Fig. 2 is a lumped parameter equivalent circuit diagram of the side output type rf resonant generator, fig. 3 is a structural equivalent schematic diagram of the side output type rf resonant generator, and fig. 4 is a structural schematic diagram of the side output type rf resonant generator. Fig. 2 is an equivalent schematic diagram of the lumped circuit of fig. 3, and fig. 3 is an equivalent schematic diagram of the distributed parameters obtained from the structure provided in fig. 4. In fig. 2, C1 is an anode bypass capacitor, C2 is an anode blocking capacitor (30 resonant cavity high voltage capacitor), C3 is an anode tank capacitor (composed of a resonant adjusting capacitor plate 17 and a box metal shell 8), C4 is a gate blocking capacitor (ceramic capacitor 15), C5 is a gate bypass capacitor (perforated capacitor 13), C6 is a feedback bypass capacitor, C7 is a cathode bypass capacitor (ceramic capacitor 14), C0 is a load capacitor (load capacitor plate 24), V is a vacuum valve, A, G, K is an anode (screen electrode), a gate and a cathode of the vacuum valve respectively, R is a gate leakage resistor, L1 is an anode choke (anode choke 19), L2 is a gate feedback adjusting inductance (gate feedback adjusting inductance 11), L3 is a gate high frequency choke (gate high frequency choke 12), L4 is a filament choke (filament choke 10), L5 is a feedback high frequency choke T is a transformer, L6 is a primary winding of the transformer (composed of the vacuum valve box 7 self inductance), and L7 is a secondary winding of the transformer (composed of an output coupling plate 21). In fig. 2, the high-frequency parallel resonant circuit is composed of a capacitor C3 and a primary winding L6 of a transformer T, namely an anode resonant tank circuit, which is a lumped parameter circuit equivalent to the parameter distributed resonant cavity structure in the invention. One end of the secondary winding L7 of the transformer T is connected with the non-grounding end of the load capacitor C0, and the other end of the secondary winding L7 is grounded, so that the L7 and the C0 form another resonant circuit, and energy transmission is realized when the resonant frequencies of the two resonant circuits are the same. The anode A of the vacuum electron tube V is connected with the positive electrode of the high-voltage rectifying part through an anode choke coil L1; one end of the cathode K is connected with the positive electrode of the filament power supply through a filament choke coil, and the other end of the cathode K is directly grounded or grounded through a capacitor; the grid G is grounded in series with the grid blocking capacitor C4 through a branch behind the grid feedback inductor L2, the other branch is grounded through the high-frequency choke coil L3, the grid bypass capacitor C5 and the grid leakage resistor R, and a coaxial cable is led out between the inductor L3 and the resistor R to be connected to the output end for feedback. The feedback capacitance of the oscillating circuit is constituted by the screen-gate capacitance Cag of the vacuum valve V. The DC blocking capacitor C2 exists between the anode and the anode resonant circuit, so that the LC high-frequency parallel resonant circuit can be ensured to have no DC signal, in the LC high-frequency parallel resonant circuit, the inductor is the self inductance structure of the vacuum electron tube box body, and forms a coupling transformer with the inductor of the output coupling polar plate, so that energy generated by resonance can be transmitted to the load output part, and the resonance and the output end are electrically isolated. The output coupling polar plate can move up and down slightly, and the coupling degree can be changed by adjusting the position of the output coupling plate so as to match the output coupling polar plate with a load. In the working process of the radio frequency insecticidal sterilization device, the change of the load capacitance C0 (caused by the change of the dielectric constant xi of a treatment material) has little influence on the resonant frequency of the radio frequency generator, and the stability of the working frequency of the device is high.
Fig. 3 is a schematic structural equivalent diagram of the side output type rf resonant generator, whose circuit characteristics and connections are determined by the fully enclosed box structure shown in fig. 4, and whose natural operating frequency is 27.12MHz (determined by the cavity structure), and the operating state and output power of the oscillating circuit are realized by applying a negative bias voltage to the gate. As shown in fig. 3, the resonant radio frequency generator is divided into an upper cavity, a middle cavity and a lower cavity, the metal shell 8 of the box body is grounded, the upper cavity is used for accommodating electric components with larger volume, such as a filament choke coil 19, a grid feedback adjusting inductor 11, a grid high-frequency choke coil 12 and the like, one end of the filament choke coil 10 is led in from the outside by a perforation capacitor 9, and the other end is connected to the cathode K of the vacuum electron tube 18; the grid feedback adjusting inductor 11 can move up and down to adjust the inductance, one end of the grid feedback adjusting inductor is connected with the grid G of the vacuum valve 18, the other end of the grid feedback adjusting inductor is connected with the grid high-frequency choke 12, and then the feedback linear success rate feedback control circuit connected out of the lower cavity output loop is introduced through the perforation capacitor 13. The intermediate cavity portion is a high-frequency resonant cavity 6, and a vacuum electron tube box 7 is installed inside the high-frequency resonant cavity. The lower cavity is used for placing wiring and filament transformers and ventilation ducts. The high-frequency resonant cavity 6 is divided into a vacuum electron tube box 7, a resonance and an output part. In the vacuum electron tube box 7, the vacuum electron tube 18V is fixed by an insulating support and an insulating plate 20, the anode A of the vacuum electron tube 18V is connected with an anode choke coil 19 and then enters a lower cavity for wiring, and the cooling of the whole vacuum electron tube box 7 depends on a forced air cooling device (arranged outside the device) arranged at the bottom. The upper plane inner surface of the resonant cavity output polar plate 16 is fixed with the upper surface of the vacuum electron tube box 7, and a gap is reserved between the resonant cavity output polar plate and the box metal shell 8 and the resonant adjusting capacitor polar plate 15 to form an anode tank circuit capacitor C3. The resonance adjusting capacitor plate 15 can move left and right to finely adjust the capacitor so as to adjust the anode resonance frequency, thereby saving expensive vacuum adjustable capacitors and being easy to adjust and maintain. The vacuum electron tube box 7 forms a resonance inductance by virtue of the structural characteristics, and is coupled with the self inductance of the output coupling polar plate 21 of the output part to form a coupling transformer T, so that energy transmission and impedance matching are realized. The output coupling polar plate 21 is fixed at the right end in the high-frequency resonant cavity 6 through the output polar mounting base 23, and the output polar plate 22 is connected with the transition plate and the output coupling polar plate 21 and is connected with the polar plate of the load capacitor C0 in the processing cavity through the soft copper foil.
As shown in fig. 4 and 5, the vacuum tube box 7 is a resonant cavity inner box 29 which is located at the central portion of the entire high-frequency resonant cavity 6, and is isolated by a resonant cavity inner cylinder closing plate 33 and fixed by screws. Also mounted in the resonant cavity inner box 29 are two resonant cavity high voltage capacitors 30 in parallel, equivalent to the anode blocking capacitor C2 in fig. 2, with one end connected to the vacuum valve anode connection plate 31 and the other end connected to the resonant cavity output plate 28. While the vacuum tube anode connection base plate 31 is connected to the anode choke 19 in fig. 3, to the lower chamber for connection to the high voltage source, because the voltage level is higher and its connection wires are insulated by the insulating support. The output coupling plate 39 is fixed by an output mounting base 38, and its position can be moved up and down to make load matching, and the whole device can be regulated to obtain maximum power output. The radio frequency output is led out from the side of the box body through the output transition electrode 27 and is connected with the upper polar plate 41 of the load capacitor C0 through the output soft copper foil, and the lower polar plate 42 of the load capacitor C0 is connected with the metal shell 8 of the box body. The metal shell 8 of the box body is grounded, the whole metal shell 8 of the box body is used as a conductor part of the resonant cavity type generator and is a grounding end, a good shielding effect on high-frequency radiation is achieved, and the manufacturing cost is reduced and meanwhile high-frequency radiation is greatly prevented.
Based on the implementation method, the box body and each conductor flat plate are preferably pure aluminum plates with the thickness of 3mm, and copper foil is copper foil strips with the thickness of 0.2 mm.
The above-described embodiments are merely preferred embodiments for fully explaining the present invention, and the scope of the present invention is not limited thereto. Equivalent substitutions and modifications will occur to those skilled in the art based on the present invention, and are intended to be within the scope of the present invention. The protection scope of the invention is subject to the claims.