KR19990034701A - Heat Strain Reduction Grid of Microwave Oscillator for Microwave Oven - Google Patents

Abstract

The present invention relates to a thermal deformation preventing grid of a microwave oven tube for microwave oven, having a circular disk shape corresponding to a cathode, a truncated slot is formed at a predetermined interval between the elongated slots, and the circle of the elongated slots. The distance between the slots in the center becomes wider and the distance between the slots in the circumference becomes smaller, but the overall slot area is characterized by maintaining the same area as that of the square slot of the conventional grid. By forming a truncated slot between the elongated slots as compared to the rectangular slot of the grid, the distance between the slots in the center of the elongated slot is widened, and the elongated slot between the elongated slot and the circumferential slot of the truncated slot. Since the distance of N becomes narrower, thermal expansion between slots in the center of center is reduced to prevent disconnection due to thermal deformation and contact with cathode. Since the internal heat can be released when out, a good heat transfer path along, has the effect that the efficiency is improved.

Description

Heat Strain Reduction Grid of Microwave Oscillator for Microwave Oven

The present invention relates to a grid of microwave oven tubes for microwave ovens, and more particularly, to a heat deformation preventing grid which can significantly reduce heat deformation by uniformizing a heat transfer path.

Applicant's Korean Patent Application No. 97-36327 discloses a microwave oven tube for microwave oven which is simple in structure and can reduce the risk of high voltage and achieve light weight. As shown in FIG. 1, the ultra-high frequency oscillation tube is provided with a power input unit 110, a heater 120, an input cavity 130, and an output cavity in a filter box 105 having a cover 104 covered therein. 140 and the feedback rod 160 are provided, and the antenna 150 in the anode 146 is provided in the bracket 102. The installation space of the antenna 150 in the filter box 105 and the anode 146 maintains a vacuum.

The cathode 132, which is an electron radiator, emits hot electrons by the indirect heating method by the heat of the heater 120, and the cathode 132 placed on the upper surface of the heater 120 is about 1000− by the heat of the heater 120. When heated to about 1300 ℃ emits hot electrons.

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-shaped disk having a hole formed in the center thereof. The first grid 134 arranged at a predetermined interval on the upper side of the N th) is applied with a bias voltage to control and focus electrons emitted from the cathode 132 to the input cavity 130. At this time, the first grid 134 and the cathode 132 is electrically insulated, that is, the direct current must be shielded, the surface current forming the microwave inside the input cavity 130 must be energized, for this purpose 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 that dissipates the slowed-down electron beam is also stacked with a plurality of cooling fins 148 to radiate heat.

The electrons focused on the input cavity 130 are densely modulated by the automatic shielding function of the bias power 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 the operating voltage is applied, the potential difference is generated therebetween, and electrons passing through the first grid 132 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 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. .

However, as shown in FIG. 2, the first and second grids 134 and 142 of the conventional microwave microwave oscillation tube are identical to each other in a shape corresponding to the cathode 132 as a metal material, and The slot 170 is formed in the circumferential direction around the hole, and a predetermined gap is maintained by the ceramic pin 172 provided between the choke structure 136 and the output cavity 140, but the slot length l ) Is long, the distance between slots on the circumference (b) is greater than the distance between slots on the circumference (a), and the ratio of the distance between slots on the center of the circle to the distance between the slots on the circumference ( b / a) is large, and when the grid is thermally expanded at the operating temperature of 1000 ° C. to 1300 ° C. of the grid, the deformation of the slot part at the center of the center is severely deformed due to thermal deformation between the slots, resulting in disconnection or contact with the cathode. There was a problem that occurred.

Accordingly, the present invention has been devised in accordance with the present invention, to provide a thermal deformation preventing grid capable of preventing thermal deformation in a conventional microwave microwave tube.

As a means for achieving the above object, the present invention is a heat distortion prevention grid of the microwave oven for microwave oven, wherein the first and second grid has a circular disk shape corresponding to the cathode, a plurality of rectangular slots Although the truncated slots are formed at predetermined intervals between the elongated slots, the distance between the center slots of the elongated slots becomes wider, and the distance between the circumferential slots becomes narrower to have a uniform heat transfer path and overall slots. The area is characterized by maintaining the same area.

According to the present invention, by forming the truncated slots at predetermined intervals between the elongated slots with the same total area of the slots, even if thermal deformation occurs between the slots, the distance between the center slots of the elongated slots is wide. As the distance between the circumferential slots is narrowed, the central slot of the elongated slot has a mechanically stable structure against thermal deformation during thermal expansion of the grid, and has a uniform heat transfer path when the heat inside is released. Therefore, the efficiency is increased by reducing the deformation of the grid by improving the heat transfer capacity.

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

FIG. 2 is a schematic plan view showing the first and second grids of FIG. 1,

3 is a schematic plan view showing a heat deformation preventing grid according to an exemplary embodiment of the present invention.

<Description of Symbols for Main Parts of 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: square shape slot

172: ceramic pin 300: thermal deformation prevention grid

310: elongated slot 320: truncated slot

Hereinafter, with reference to the accompanying drawings will be described in detail the thermal deformation preventing grid of the microwave oven tube for microwave oven according to an embodiment of the present invention.

As can be seen from FIG. 3, the thermal deformation preventing grid 300 of the microwave microwave oscillation tube of the present invention has a circular disk shape corresponding to the cathode 132, and the first and second grids have the same shape. .

In the heat deformation preventing grid 300 of the present invention, a plurality of elongated slots 310 and a truncated slot 320 are respectively formed, and a truncated slot 320 is disposed between the elongated slots 310 at predetermined intervals. Is formed. At this time, the total area of the elongate slot 310 and truncated slot 320 is preferably the same as the total area of the rectangular slot 170 of the conventional grid. That is, even if the truncated slot 320 is formed between the elongated slots 310, the overall slot area is the same area, so that the slots between the far center slots of the elongated slots 310 are compared with the conventional grid slot structure. The distance A becomes wider, and the distance B between the truncated slot 320 and the circumferential slot of the elongated slot 310 becomes smaller to have a uniform heat transfer path.

As described above, the thermal deformation preventing grid 300 of the present invention is thermally expanded when the cathode 132 reaches an operating temperature, that is, 1000 ° C. to 1300 ° C., due to the heat of the cathode 132. While maintaining the same area as the area, the distance between the slots in the center of the elongated slot 310 is wider than the conventional grid slot structure, and between the elongated slots 310 and the circumferential slots in the truncated slots 320. Since the distance of N is narrow and has a uniform heat transfer path, heat deformation between slots on the far center side of the elongated slot 310 is reduced, so that contact with each other is prevented.

According to the present invention, by forming a truncated slot between the elongated slots, as compared to the square slots of the grid of the conventional microwave microwave tube, the distance between the slots in the center of the elongated slots becomes wider Since the distance between the elongated slot and the circumferential slot of the truncated slot is narrowed, the thermal expansion between the slots in the center of the slot is reduced to prevent contact with the cathode by disconnection and deflection, and thus the heat inside is discharged out. In this case, the heat transfer path can be improved, and thus the efficiency is improved.

Claims (2)

A power input unit, heat generating means for generating heat by receiving power from the power input unit, cathodes sequentially installed on the heat generating means at predetermined intervals, a first grid, and a choke structure provided between the cathode and the first grid; As the input cavity of the space surrounded by the cathode, the cathode is heated to a predetermined operating temperature by the heat of the heat generating means to emit hot electrons, the first grid is formed with a plurality of square slots, a bias voltage is applied to the cathode The choke structure conducts surface currents that form a microwave inside the input cavity, and direct current between the cathode and the first grid shields the input cavity, radiating heat. A plurality of cooling fins are stacked and arranged so as to extinguish the decelerated electron beam; A space enclosed by a second grid installed on top of the first grid to induce surface currents while electrons passing through the first grid of the cavity pass through the first grid and the first while the electrons focused on the input cavity are density modulated. An output cavity accelerated by the potential difference between the two grids, the microwaves being formed by the surface current induced in the second grid, radiating means for radiating the microwaves formed in the output cavity, and a part of the microwaves formed in the output cavity In the grid of the microwave oscillation tube for microwave ovens consisting of a feedback means provided between the input and output cavity to feed back to the input cavity, The first and second grids have a circular disk shape corresponding to the cathode, wherein a truncated slot is formed at predetermined intervals between the elongated slots, and the distance between the slots in the center of the elongated slot is widened. The distance between the circumferential slot is narrow, the thermal deformation preventing grid of the microwave oven for microwave oven, characterized in that the distance between the uniform slot. The grid of claim 1, wherein the total slot area of the grid maintains the same area as the total area of the rectangular slot.