KR19990012809A - microwave - Google Patents

Abstract

The present invention relates to a microwave oven employing a novel ultra-high frequency oscillation tube, and compared to a microwave oven employing a conventional klystron, not only ensures stability against high pressure, but also compared to a conventional microwave oven using a conventional magnetron. Since no high voltage circuit part is required, weight reduction is achieved, and since the electron beam is focused using the first and second grids, an external magnetic field magnet is unnecessary, and the cathode, the first and second grids, and the anode form a planar structure. The structure is simplified, the weight is achieved, and since the bias power from the outside is unnecessary by the auto bias function of the first grid, the cost of the product is reduced.

Description

microwave

The present invention relates to a microwave oven, and more particularly, to a microwave oven employing an ultra-high frequency oscillation tube that can eliminate the risk due to high voltage and achieve light weight.

As is well known, a microwave oven employs, for example, a magnetron driven at a high voltage of 4 kV as an ultra high frequency oscillation tube. Such a magnetron is a kind of two-pole vacuum tube that generates microwaves, and as shown in FIG. Is emitted into the working space 4 between the ends of the plurality of vanes 3 and the filament 1 extending on the inner wall of the cylindrical anode 2, and an electric field of 4 kV is formed in the working space 4. In addition, a magnetic field is applied to the working space 4 by a magnetic circuit composed of a magnet 5 and a magnetic pole 6 so that hot electrons undergo a cycloid movement, and the energy of the movement is taken into the vane 3 and the strap 8. ) Is radiated to the cooking chamber through an output unit consisting of an antenna 7 connected to the vanes 3, an antenna ceramic 9, an antenna seal 10, and the like, thereby thawing and heating foodstuffs.

However, such a conventional magnetron for a microwave oven requires a high voltage transformer and a high pressure diode according to a high pressure driving, so there is a problem in safety, and a magnet is required because it adopts a resonance method by electromagnetic movement in an electromagnetic field. This was heavy and expensive to manufacture.

2 and 3 illustrate a microwave oven employing Klystron as disclosed in US Patent No. 5,541,391 as an ultra-high frequency oscillation tube. Such a microwave oven is usually operated by the control panel 10 arranged on the front right side of the casing 20 of the microwave oven, so that the power supply unit 31 installed inside the casing 20 has a klystron 40 and a cooling fan ( 38, the klystron 40 is operated by the operating voltage from the power supply unit 31 to emit microwaves through the antenna 32. The emitted microwaves are guided to the cooking chamber 35 through the waveguide 33. The microwaves introduced into the cooking chamber 35 are spread by the stirrer 34 to irradiate the food in the cooking chamber 35 to perform cooking. On the other hand, since the cooling fan 38 is arranged behind the klystron 40 to generate a wind for cooling the klystron 40 and the temperature is increased, the heated air is transferred to the inlet 37 by the duct 39. It is guided and introduced into the cooking chamber 35.

As shown in FIG. 4, the chrystron 40 includes an input terminal 42 for receiving a power source, a klystron body 41 for generating microwaves in response to the supply of power to the input terminal 42, and An antenna 32 for transmitting microwaves from the Klystron body 41, a cooling unit 43 for radiating heat generated in the Klystron body 41 to the outside, and an electron beam concentrator provided to receive electrons ( 49, the cooling unit 43 supports the cooling fins 44 and the cooling fins 44 arranged to disperse heat generated by the reception of electrons, and from the electron beam concentrator 49 It consists of a cooling rod 46 arranged to transfer the heat of the cooling fins 44, and a closure 48 surrounding the cooling fins 44.

The klystron 40 also receives a power supply via the input terminal 42, and a pair of electron guns 50, which generate electrons by the received power supply, and a pair of electron guns 50 and the electron beam concentrator 49, respectively. The magnet 52, the yoke 54 which acts as a guide | route which comprises the closed loop by this magnet 52, and the tube 56 interposed between the magnet 52 with the some cavity is included.

However, the microwave oven employing Klystron still applies high voltage, so the input terminal has to be insulated from the Klystron body with a separate insulation member, so the product becomes heavy and the movement method of the electron is complicated, so the cooling structure is complicated and many It should be a structure having a cavity of, and a magnet is needed because the electron beam focusing structure is needed, and also a filter is required, which has a complicated structure.

Therefore, the present invention has been devised according to the present invention, by adopting a microwave generator as a microwave generator by moving the electrons linearly to generate microwaves, it is possible to ensure stability against high pressure and to reduce the weight due to the simplification of the structure. To provide.

As a means for achieving the above object, the microwave oven of the present invention is a power input unit, a heat generating means for generating heat by receiving power from the power input unit, a cathode sequentially installed at predetermined intervals on top of the heat generating means, An input cavity of a space surrounded by a grid and a choke structure provided between the cathode and the first grid, wherein the cathode is heated to a predetermined operating temperature by the heat of the heat generating means to emit hot electrons, and the first grid Is a bias voltage applied to focus electrons emitted from the cathode, and the choke structure is an input that conducts surface current by forming a microwave inside the input cavity and shields direct current between the cathode and the first grid. The cavity and a plurality of cooling fins are stacked to radiate heat, and the decelerated electron beam is extinguished. The key is a space surrounded by an anode and a second grid mounted on top of the first grid to induce surface currents as electrons passing through the first grid of the input cavity pass, where electrons focused in the input cavity Is modulated by an electric potential difference between the first grid and the second grid, and radiates radiating microwaves formed in the output cavity, the output cavity of which microwaves are formed by the surface current induced in the second grid. And an ultra-high frequency oscillating tube comprising a means and a feedback means provided between the input and output cavities so as to feed back a portion of the microwaves formed in the output cavity to the input cavity.

1 is a schematic cross-sectional view showing the structure of a magnetron employed as an ultra-high frequency oscillation tube in a conventional microwave oven,

2 is a schematic diagram of a conventional microwave oven employing Klystron as an ultra-high frequency oscillation tube,

3 is a side view of FIG. 2,

4 is a cross-sectional view showing the structure of the klystron of FIG.

5 is a cross-sectional view showing the structure of an ultra-high frequency oscillation tube employed in a microwave oven in accordance with a preferred embodiment of the present invention.

6 is an enlarged detail view of the main portion of FIG. 5;

FIG. 7 is a perspective view illustrating the cathode of FIG. 6;

FIG. 8 is a perspective view illustrating the first and second grids of FIG. 6.

Explanation of symbols on the main parts of the drawings

100: high frequency oscillation tube 102: bracket

104: filter box cover 110: power input unit

120: heater 130: input cavity

132: cathode 134: first grid

136: choke structure 140: output cavity

142: second grid 144: projection

146: anode 148: cooling fin

150 antenna 152 coupling end

154: antenna ceramic 156: antenna cap

160: feedback rod 170: slot-shaped rectangular opening

172: ceramic pin

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Since the microwave oven according to the preferred embodiment of the present invention has the same configuration as a conventional microwave oven except for the microwave oscillation tube as a microwave oscillator, the microwave oscillation tube will be described in detail for convenience of description.

As shown in FIG. 5, the microwave oscillation tube 100 employed in the microwave oven according to the preferred embodiment of the present invention includes a power input unit 110 in a filter box 105 covered with a cover 104 at a lower portion thereof. The heater 120, the input cavity 130, the output cavity 140, and the feedback rod 160 are provided, and the antenna 150 in the anode 146 has the same bracket as that of a conventional magnetron. It is installed in 102). The interior of the filter box 104 and the installation space of the antenna 150 in the anode 146 maintain a vacuum.

The ultra-high frequency oscillation tube 100 employed in the microwave oven of the present invention emits hot electrons by the cathode 132, which is an electron radiator, by an indirect heating method by the heat generation of the heater 120 composed of an annular filament as a heating means. That is, as shown in FIG. 5, when the cathode 132 placed on the top surface of the heater 120 is heated to about 600-1200 ° C. by the heat of the heater 120, the electrons are emitted.

The input cavity 130 is a space surrounded by the cathode 132, the first grid 134, and the choke structure 136, and the cathode 132 is a ring having a hole formed in the center thereof, as shown in FIG. 7. As a disk of the type, the first grid 134 arranged at a predetermined interval on top of the cathode 132 is applied with a bias voltage to control and focus electrons emitted from the cathode 132 to the input cavity 130. At this time, since the first grid 134 and the cathode 132 is electrically insulated, that is, the direct current therebetween must be shielded, and the surface current due to the microwave formation inside the input cavity 130 must be energized. For this purpose a choke structure 136 is arranged between the cathode 132 and the first grid 134.

The output cavity 140 arranged on the top of the input cavity 130 is installed to face the top of the first grid 134 of the input cavity 130 so that electrons passing through the first grid 134 pass through the surface current. Is enclosed by a second grid 142 and an anode 146 having protrusions 144 protruding downward from the bottom surface. In this space, electrons focused on the input cavity 130 are densely modulated. Accelerated by the potential difference between the grid 134 and the second grid 142, the microwave is formed by the surface current induced in the second grid 142. The anode 146 is also stacked with a plurality of cooling fins 148 to radiate heat, and extinguishes the reduced electron beam.

As shown in FIG. 8, the first and second grids 134 and 142 are identical in shape to the cathode 132 as a metal material, and have a slot-shaped quadrangle along the circumferential direction around an inner hole. An opening 170 is formed and a predetermined gap is maintained by the ceramic pin 172 provided between the choke structure 136 and the output cavity 140.

Electrons accumulated in the input cavity 130 are densely modulated by the automatic shielding function of the bias power supply of the first grid 134 to pass through the first grid 134, and at this time, the input / output cavities 130 and 140 insulated from each other. When the operating voltage is applied, the potential difference is generated therebetween, and electrons passing through the first grid 134 are accelerated to pass through the second grid 142, so that surface current is generated in the output cavity 140. Induced. As a result, microwaves are formed in the output cavity 140, and the formed microwaves penetrate through the center of the anode 146 and are radiated through the antenna 150 formed in the output cavity 140. For this purpose, the coupling end 152 of the antenna 150 is located in the output cavity 140. The antenna ceramic 154 and the antenna cap 156 connected to the upper portion of the antenna 150 have the same structure as a conventional marknetron.

Meanwhile, a feedback rod 160 for feeding back a portion of the microwaves formed in the output cavity 140 to the input cavity 140 is installed at the center between the input / output cavities 130 and 140 to amplify the power of the microwave and resonate. Let's do it.

According to the microwave oven of the present invention, compared to the microwave oven employing the conventional klystron, not only the stability to high pressure is secured, but also the weight reduction is achieved because no high voltage circuit part is required as compared to a conventional microwave oven using a conventional magnetron. Since the electron beam is focused using the first and second grids, an external magnetic field magnet is unnecessary, and since the cathode, the first and second grids, and the anode form a planar structure, the structure is simplified and the weight is achieved. The auto-biasing function of the first grid eliminates the need for a separate bias power supply from the outside, thereby reducing the cost of the product.

Claims (6)

In the microwave, Power input unit, Heating means for generating heat by receiving power from the power input unit; An input cavity of a space enclosed by a cathode sequentially arranged at a predetermined interval on the heat generating means, a first grid, and a choke structure provided between the cathode and the first grid, the cathode being predetermined by heat generation of the heat generating means. Heated to an operating temperature of to emit hot electrons, the first grid is supplied with a bias voltage to control and focus electrons emitted from the cathode, and the choke structure is a surface current that forms a microwave inside the input cavity is energized. An input cavity shielding a direct current between the cathode and the first grid; A plurality of cooling fins are stacked and arranged to radiate heat, and an anode for quenching the decelerated electron beam, and an electron passing through the first grid of the input cavity, installed on top of the first grid to induce surface current while passing. A space surrounded by a second grid, in which the electrons focused in the input cavity are densely modulated, accelerated by the potential difference between the first grid and the second grid, and by the surface current induced in the second grid An output cavity in which microwaves are formed, Radiating means for radiating microwaves formed in the output cavity; And an microwave oscillation tube comprising a feedback means provided between the input and output cavities so as to feed back a portion of the microwaves formed in the output cavity to the input cavity. The microwave oven according to claim 1, wherein the density modulation of the electrons focused on the input cavity is performed by an automatic shielding function of the bias power supply of the first grid. The microwave oven according to claim 1, wherein the inside of the microwave oscillation tube maintains a vacuum. The method of claim 1, wherein the cathode is a disk in the form of a ring, the first and second grid is a circular metal material corresponding to the cathode, the slot-shaped rectangular opening in the circumferential direction around the inner hole is formed Microwave oven characterized in that. The electronic device of claim 1, wherein the feedback means feeds back a portion of the microwaves formed in the output cavity to the input cavity using a feedback rod formed at the center of the cavities to amplify and resonate the power of the microwave. Range. The microwave oven of claim 1, wherein the input / output cavities are insulated from each other, and the distance therebetween maintains a distance of several tens to several hundred microns.