KR19990056492A - Micro-Crystal Drive Circuit of Microwave Oven - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro-clit rod driving circuit of a microwave oven, comprising: a heater 125 that generates heat by a predetermined AC power source, and a cathode that is heated to a predetermined operating temperature by heat generation of the heater 125 to emit hot electrons. 132, a first grid 134 that accumulates electrons emitted from the cathode 132, and a second grid that generates microwaves by inducing surface current while electrons passing through the first grid 134 pass through 142, and a circuit for driving a micro-clist including an anode 146 for outputting the microwaves generated in the second grid 142, the anode and back pressure rectified by a 500 to 700Vdc power source A back pressure rectifying circuit portion 200 applied to the cathode; The heater 125 is characterized by being a commercial power heater that is driven by a commercial power source of 110 to 230Vac to generate heat.

Therefore, the present invention can configure the driving circuit without using a pressure-sensitive transformer, there is an effect that can reduce the weight of the microwave oven and lower the price.

Description

Micro-Crystal Drive Circuit of Microwave Oven

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a micro-clist drive circuit used as a microwave generator tube in a microwave oven, and in particular, without using a reduced pressure transformer for applying a predetermined AC power to a heater of a micro-klystrode. The present invention relates to a micro-clit rod driving circuit of a microwave oven capable of driving a micro-clid rod.

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. This magnetron is a kind of two-pole vacuum tube that generates microwaves, and as shown in FIG. 1, when electric power is applied to an input part composed of a condenser 11, a choke coil 12, and the like, the hot electrons emitted from the filament 1 of the cathode part. 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 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. By heating the foodstuffs by radiating the microwaves to the cooking chamber (not shown) through an antenna 7 connected to the vane 3 and an output unit composed of the A ceramic 9 and the A seal 10, etc. And cooked.

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

To solve this problem, FIG. 2 shows a microwave oven employing Klystron disclosed in US Patent No. 5,541,391 as an ultra-high frequency oscillation tube. As shown in FIG. 2, the Klystron 40 has an input terminal 42 for receiving a power source and a Klystron main body that generates microwaves, that is, ultra-high frequencies in response to the supply of power to the input terminal 42. (41), an antenna (32) for transmitting microwaves from the Klystron body (41), a cooling unit (43) for dissipating heat generated in the Klystron body (41) to the outside, and installed to receive electrons An electron beam concentrator 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 supports the electron beam concentrators. It consists of a cooling rod 46 arranged to transfer heat from 49 to 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 mark 52 with the some cavity is included.

However, the microwave oven employing Klystron is still driven by a high voltage power supply, so the input terminal must be insulated from the Klystron body with a separate insulating member, and a high voltage transformer is needed to boost the commercial power to high voltage, thus making the product heavy. In addition, since the motion of the electrons is complicated, excessive noise is generated, the cooling structure is complicated, and the structure has a plurality of cavities. A magnet is required for focusing the electron beam, and a filter is required, so the structure is complicated. There was a downside.

Therefore, in order to overcome these disadvantages, a microwave oven using a micro-klystrode, which is operated at a low voltage and has a simple structure, eliminates the risk of high voltage and achieves a light weight, has been developed.

3 is a cross-sectional view showing the structure of the micro-clist as described above.

As shown in FIG. 3, the micro-clist rod 100 includes a power input unit 110 that receives a low voltage, a heater 120 that generates power by receiving power from the power input unit 110, and the heater ( Input cavity including a ring-shaped cathode 132 sequentially installed at a predetermined interval on the upper portion of the 120, and a blocking capacitor 136 having a choke structure provided on the side of the first grid 134 and the cathode 132 130, the cathode 132 is heated to a predetermined operating temperature by the heat of the heater 120 to emit hot electrons, and the first grid 134 is applied with a bias voltage to the cathode 132. Electrons emitted from the capacitor, and the blocking capacitor 136 energizes the surface current due to the formation of microwaves in the input cavity 130, and the cathode 132 and the first grid 134 are insulated from each other. To radiate heat An anode 146 in which several cooling fins 148 are arranged radially and an electron passing through the first grid 134 of the input cavity 130 pass through the second grid 142 to induce surface current. And the output cavity 140 in which the electrons accumulated in the input cavity 130 are density-modulated, and the microwaves are formed by the surface current induced by accelerating the modulated electrons, and the microwaves formed in the output cavity 140. And a feedback means 160 provided between the radiating antenna 150 and the input / output cavities 130 and 140 to feed back a portion of the microwaves formed in the output cavity 140 to the input cavity 130. do.

On the other hand, Figure 4 is a view showing a driving circuit for driving the micro-clist as described above.

As shown in FIG. 4, the power applied to the anode 146 and the cathode 132 is rectified by a back pressure rectification at about 550 Vdc in the back pressure refinery circuit 200, and the power for heating the heater 120 is a reduced pressure transformer. The former is converted to about 10 to 12Vac in the former 300 and applied to the heater 120.

That is, as described above, the conventional micro-clit rod driving circuit not only converts an AC commercial power of about 120V or 220V into a DC power of about 550V, but also provides a back pressure rectifier circuit for providing the anode and the cathode. In order to supply to the heater to provide a reduced pressure transformer for converting the pressure to 10 to 12Vac, there was a problem that the weight of the microwave is increased and the price is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a microclad rod and a driving circuit for driving the same, without having a pressure reducing transformer for generating a 10 to 12 Vac power supplied to a heater. The present invention provides a micro-crust rod driving circuit of a microwave oven capable of driving a micro-crust rod by heating a heater.

According to a preferred embodiment of the present invention for achieving this object, a heater that generates heat by a predetermined AC power, a cathode that is heated to a predetermined operating temperature by the heat of the heater to emit hot electrons, and the cathode 132 A first grid for accumulating electrons emitted from the second grid; a second grid for generating microwaves by inducing surface current while electrons passing through the first grid pass; and an anode for outputting microwaves generated in the second grid. In the circuit for driving a micro-clystlide, The circuit includes a back-pressure rectification circuit portion for applying the voltage back to the anode and the cathode by rectifying the commercial power to 500 to 700Vdc power, the heater by the commercial power It is characterized in that driven to generate heat.

1 is a schematic cross-sectional view showing the structure of the mark netron used as an ultra-high frequency oscillation tube for a microwave oven,

2 is a schematic cross-sectional view showing the structure of Klystron used as a microwave microwave tube for microwave oven,

Figure 3 is a cross-sectional view showing the structure of the micro-clides used as a microwave microwave oscillation tube,

FIG. 4 is a view showing a driving circuit for driving the micro-crust rod shown in FIG.

5 is a view showing a driving circuit for driving a microclid rod according to the present invention.

<Description of the code | symbol about the principal part of drawing>

100: micro climb rod 102: bracket

104: filter box 110: power input unit

120, 125: Heater 130: input cavity

132: cathode 134: first grid

136: blocking capacitor 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 200: back pressure rectifier circuit

300: decompression transformer

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

FIG. 5 is a circuit diagram illustrating an improved micro-crusted drive circuit according to a preferred embodiment of the present invention.

As shown in FIG. 5, the present invention provides a back pressure rectifying circuit 200 for back pressure rectifying the input commercial power at about 550 Vdc, and a cathode 132 and an anode 146 to which the output power of the back pressure rectifying circuit 200 is applied. And a heater 125 to which commercial power is directly applied.

3 and 5, an improved micro-clith drive circuit according to the present invention will be described in detail.

The power input unit 110, the heater 120, the input cavity 130, the output cavity 140, the antenna 150, and the feedback rod 160 are provided in the bracket 102, and the bracket The lower portion of the 102 is attached to the filter box 104, the inside is configured to maintain a vacuum.

In the microclid rod 100, the cathode 132, which is an electron emitter, emits hot electrons by an indirect heating method by heating of the heater 120 formed of an annular filament. That is, as shown in FIG. 5, when the cathode 132 placed on the upper surface of the heater 120 is heated to about 1000-1100 ° C. by the heat generated by the heater 120, hot electrons are emitted.

At this time, the anode 146 and the cathode 132 are supplied with a back-pressure rectified power of about 500 to 700 Vdc, preferably about 550 Vdc, in the back pressure rectifying circuit unit 200, and a commercial power is directly applied to the heater 125.

As shown in FIGS. 4 and 5, the cathode 132 is a ring-shaped disk having a hole formed in the center thereof. The first grid 134 arranged at predetermined intervals on the cathode 132 has a bias voltage. Electrons applied and emitted from the cathode 132 accumulate in the input cavity 130. In this case, the first grid 134 and the cathode 132 form part of the input cavity 130, and the first grid 134 and the cathode 132 are electrically insulated from each other. Since the surface current due to microwave formation must be energized, a blocking capacitor 136 having a choke structure is arranged on the side of the input cavity 130 for this purpose.

The output cavity 140 arranged on the top of the input cavity 130 has a body with the second grid 142 facing the first grid 134 of the input cavity 130 with a predetermined gap therebetween. The anode 146 is formed with a protrusion 144 protruding downward. The anode 146 also has a plurality of cooling fins 148 arranged radially to radiate heat.

As shown in FIG. 6, the first and second grids 134 and 142 are identical to each other in a shape corresponding to the cathode 132 as a Mo-Re material, and have a slot-shaped rectangular opening 170 along the circumferential direction. ) Is formed and a predetermined gap is maintained by the ceramic pin 172 provided between the blocking capacitor 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 132 to pass through the first grid 132, and at this time, the input / output cavities 130 and 140 insulated from each other. When a low voltage operating voltage of about 500-700 VDC is applied from the back pressure rectifying circuit unit 200, a potential difference is generated therebetween, whereby electrons passing through the first grid 132 are accelerated to form a second grid 142. ), Surface current is induced in the output cavity 140. 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.

In addition, a feed rod 160 for feeding back part 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 and resonate the power of the microwave. .

On the other hand, the heater 125 according to the present invention can be used by applying a commercial power as described above, the operating temperature is about 1200 ℃, the reaching time to this operating temperature, that is, the operating time is 5 to 10 seconds. . In addition, the heater 125 has an output power of about 90W to 175W, and the material uses tungsten (W) or tungsten-renium (WRe) wire. As the content of rhenium (Re) increases, the resistance increases. That is, for example, when about 3% of rhenium is added, the resistance is about 1.5 times larger than that of tungsten wire, and when about 25% of rhenium is added, the resistance is about 5.7 times larger than that of tungsten wire. Accordingly, the heater 125 may be manufactured by adjusting the content of rhenium in consideration of such a resistance value or by using only tungsten in some cases.

As described above, the present invention can configure the drive circuit without using a pressure-sensitive transformer for supplying 10 to 12 Vac to the heater in constructing the drive circuit of the micro-clist, thereby reducing the weight of the microwave oven. The effect is to lower the price.

Claims (5)

A heater that generates heat by a predetermined AC power source, a cathode that is heated to a predetermined operating temperature by heat generation of the heater to emit hot electrons, a first grid that accumulates electrons emitted from the cathode, and the first grid In a circuit for driving a micro-clist comprising a second grid for generating microwaves by inducing surface current while passing electrons and an anode for outputting microwaves generated in the second grid, The circuit includes a back-pressure rectifying circuit unit for back-pressure rectifying the commercial power to 500-700 Vdc power and applying it to the anode and the cathode; The heater is a micro-clit rod drive circuit of a microwave oven, characterized in that the heater for commercial power is driven by a commercial power source of 110 to 230Vac to generate heat. The microwave oven of claim 1, wherein the heater has a driving temperature of about 1200 ° C. 3. The micro-clit rod drive circuit of claim 2, wherein the heater is about 5 to 10 seconds to reach the drive temperature. 4. The microwave oven of claim 3, wherein the output power of the heater is about 90 to 175 watts (w). The microwave oven of claim 4, wherein the heater is made of tungsten or tungsten-renium wire.