A Double Tube Microwave Oven Using Circularly Polarized Helical Antenna as Radiator

Abstract

The invention belongs to a double-tube microwave oven using a circularly polarized helical antenna as a radiator for food cooking, including a casing, a heating cavity inside the casing, and an upper and a lower set of magnetrons with identical structures isolated from the heating cavity. Tube and its "L"-shaped energy-feeding waveguide composed of a vertical waveguide and a horizontal waveguide with a waveguide outlet, an electrical box including a power supply, a fan, and a circuit board, a furnace door, and a control button or knob with a circuit Circularly polarized helical antennas are installed at the waveguide exits of each energy-feeding waveguide, and the top of each antenna is placed on the bottom or top of the heating chamber. The bottom and top of the furnace are insulating dielectric plates . The invention has the characteristics of simple structure, light furnace body, high power density and high power in the furnace cavity, uniform heating of microwave radiation and heated objects, fast heating speed, long service life and low production cost, and is especially suitable for microwave ovens. In fast food restaurants, restaurants, hotels and other places that require rapid heating.

Description

technical field [0001] The invention belongs to microwave ovens for food cooking, in particular to a double-tube microwave oven using a circularly polarized helical antenna as a radiator to radiate high-speed rotating electromagnetic waves (the rotation rate is the same as the operating frequency of the microwave source) to make heating (resonance ) Microwave oven in which the microwave radiation in the cavity and the object to be heated are heated evenly. When the operating frequency of the microwave is 2450MHz, the rotation speed of the microwave is 2.45×10 9 r / sec (that is, the speed is 1470×10 8 rpm's super high-speed rotation). Background technique [0002] It has been nearly 70 years since the microwave oven was invented. Traditional microwave ovens include a shell, a microwave heating (resonance) cavity inside the shell, and a microwave-containing magnetron (microwave generator) and its energy-feeding waveguide isolated from the microwave heating cavity. , switching...

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Problems solved by technology

[0002] It has been nearly 70 years since the microwave oven was invented. Traditional microwave ovens include a shell, a microwave heating (resonance) cavity inside the shell, and a microwave-containing magnetron (microwave generator) and its energy-feeding waveguide isolated from the microwave heating cavity. , switching power supply (or transformer), cooling fan, electrical box including the control circuit board, the furnace door and circuit control panel on the front of the shell; the feeding of the microwave power usually has the following methods, one. The turntable Type microwave oven: this type of microwave oven is to open a rectangular window from an appropriate position on a side wall (usually the right side) of the microwave oven cavity, and this window is connected with the energy-feeding waveguide of the magnetron (microwave source). linear polarization field, and directly radiate microwaves (power) with a fixed electric field direction into the furnace cavity. The heating uniformity of the object to be heated (placed) on it, the household microwave oven commonly used by people many years ago is this type of turntable microwave oven. Although this type of microwave oven solves the heating (heating) uniformity problem to a certain extent, but Due to the complex structure, the weight of the furnace, and the periodic changes in the heating temperature of the object to be heated, the overall (especially the solid object) is still not evenly heated; second. Flat-plate microwave oven: This type of microwave oven feed waveguide is located at the bottom or bottom of the furnace cavity and the top, open a window directly on the top of the wide side of the waveguide, and install an insulating medium shaft in the center of the feed hole (square hole), and place an asymmetrical metal blade on the top of the shaft, and place it at the bottom of the shaft (outside the waveguide) ) to install a slow rotating motor, which drives the top blades to rotate through the rotating shaft, forming a so-called "mode stirrer". The object is evenly heated, but the power density in the furnace cavity and the uniform heating of the heated object are still difficult to effectively improve; the patent document with the announcement number CN204574146U and the invention name "Microwave Oven" belongs to this type of flat-panel microwave oven. The microwave oven is equipped with a waveguide and the first and second microwave stirring devices with drive motors respectively located on the bottom and top of the oven cavity (accommodating cavity) in order to make the microwave distribution in the oven cavity more uniform; in addition, Another flat-panel microwave oven is based on the above-mentioned structure, and the rotating shaft in the mode stirrer is replaced by a metal shaft, which forms an active antenna together with the metal blades, and the microwave power is directly radiated from the antenna blades into the oven cavity. In addition, a few years ago, Japan's Matsushita Corporation once launched a commercial dual-source microwave oven on the market, but its energy feeding device uses an active antenna, which rotates at a slow speed with a motor, and the two antennas are placed in the oven cavity respectively. The bottom and top of the microwave oven rotate in opposite directions relative to each other, and radiate microwave power to the food placed between the two antennas to achieve the purpose of rapid and uniform heating; Complicated, high production cost, and there are still problems of microwave distribution in the furnace cavity and poor heating of the heated object

The publication number is CN204648356U, and the patent document titled "Microwave Oven" is aimed at the disadvantages of the above-mentioned patented technology, such as complex structure, on the basis of improving a design of a microwave oven. The microwave oven is arranged on the outside of the box. Multiple magnetrons are arranged on the same waveguide, and the stirring motor is also arranged on the waveguide, and its main shaft is placed inside the waveguide, and the main shaft is connected with stirring blades. The microwave oven uses multiple magnetrons to share one waveguide tube and a stirring motor to reduce the production cost and overcome the high production cost defect of the previous patented technology. The microwave of each branch enters the through hole from the same microwave outlet, but there are disadvantages of microwave interference and affecting its power output;

[0003] Thereby, above-mentioned conventional microwave ovens all exist need to adopt electric motor and be provided with blade stirrer or (loading) turntable this kind of more complicated rotating system, and because what adopted is the motor transmission system of slow-speed rotating electric motor or belt deceleration mechanism, the stirring blade The rotation speed is limited or the microwaves of each branch enter the through hole from the same microwave outlet. The microwaves interfere with each other and affect their power output, and the microwave power density is low, and the heated object is still heated unevenly.

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