KR100674130B1 - High frequency heating cooker - Google Patents

Abstract

Conventionally, in cooking using a heating member that absorbs microwaves and generates heat, microwaves are not uniformly distributed in the heating chamber, so that the heating member also has a high temperature portion and a low temperature portion, and so-called heating imbalance occurs. It was happening.

And a control unit for controlling the driving of the magnetron, the food base having a magnetron for supplying microwaves in a heating chamber to microwave the food, a heating element that can be stored in the heating chamber, and absorbs the microwaves and generates heat. The control unit performs preheating and cooking steps when cooking the food using the food stand, and at the same time, the first half of the preheating step drives the magnetron at a high output. The latter half is configured to drive the magnetron by lowering its output.

     Heating chamber, magnetron, food tray, heating layer, waveguide

Description

High Frequency Heating Cooker {HIGH FREQUENCY HEATING COOKER}             

1 is an external view of an oven range which is one embodiment of the present invention.

2 is a cross-sectional view taken along line A-A in FIG.

3 is an external view of a tray for food placement.

Figure 4 is a control block diagram of the oven range of the present invention.

Fig. 5 is an operation flow chart of a control circuit for preheating the tray for food placing of the present invention and then cooking cooking.

6 is a diagram showing a relationship between a preheating time and a temperature of a magnetron output or a food tray.

<Explanation of symbols for main parts of drawing>

7: heating chamber 8: magnetron

14: food tray 18: heating layer

The present invention relates to a high frequency heat cooker.

Background Art Conventionally, it is well known to bake food using a food stand equipped with a heat generating member that generates heat by absorbing micron waves.

In this preliminary baking process, first, in the preheating step, only the food stand is placed in the heating chamber, the food stand is heated and preheated, and then the food is placed on the prototype stand and the food stand is baked. Heating cooking is performed. (See Patent Document 1, for example)

[Patent Document 1] Japanese Patent Application Laid-Open No. 2003-222340

However, in the heating member of the food stand, the microwaves are not uniformly distributed in the heating chamber, and the heating output is uneven. As a result, even in the heat generating member, a portion having a high temperature and a portion having a low temperature were formed, and a heating unevenness was generated, which was not uniform in temperature distribution.

For this reason, for example, when fried eggs are cooked, there are surely baked places and soft-boiled places, and the finishing is not so good.

The present invention has been made to solve such a problem.

The high frequency heating cooker of the present invention has a heating chamber that can accommodate food, a magnetron that supplies microwaves in the heating chamber to microwave the food, and a heating member capable of storing in the heating chamber and absorbing the microwaves to generate heat. And a control unit for controlling the driving of the magnetron, wherein the control unit performs a preheating step and a cooking step at the same time when performing cooking to bake the food using the food stand. In the first half, the magnetron is driven at a high output, and the second half is driven by lowering the output of the magnetron.

According to this invention, the temperature of a food stand becomes substantially uniform and it is possible to control uneven cooking completion.

EMBODIMENT OF THE INVENTION Hereinafter, the microwave oven which becomes one Example of this invention is demonstrated based on each drawing.

In FIG. 1, 1 is a microwave oven body, 2 is an exterior, 3 is a door which can be opened horizontally, and 4 is a handle installed in the door 3, 5 is an operation part which inputs a start operation or a cooking condition. The operation part 5 has a display part which displays the key input part 6, input content, etc.

In Fig. 2, reference numeral 7 denotes a heating chamber installed in the exterior 2, 8 denotes a magnetron for oscillating microwaves and supplies microwaves in the heating chamber 7, 9 denotes a waveguide for propagating microwaves oscillated in the magnetron 8, and 10 denotes a heating chamber 7 Rotation is freely installed at the bottom of the antenna, radiates the microwaves in the waveguide 9 to the heating chamber, and diffuses the rotating antenna, 11 is an antenna motor for rotating the rotating antenna 10 by connecting a rotating shaft to the rotating antenna 10, 12 is rotated The bottom part of the heating chamber 7 which installed the antenna 10 is partitioned, and it is a ceramic bottom plate which can be placed in food.

Numeral 13 denotes a food placing tray which is mounted on rail 13 so that a tray for storing food in the heating chamber 7 can be stored therein and 16 is an infrared sensor that detects the food temperature in the heating chamber 7. . As shown in FIG. 3, the food placing tray 14 has a food placing portion 15, a side wall portion 16, a horizontal extension extending from the head 17 and a rear surface of the food placing portion 51. And a heat generating layer 18 corresponding to a heat generating member that absorbs microwaves and generates heat, and is cooked to bake food placed on the food placing tray 14 by the heat generated by the heat generating layer 18.

In FIG. 4, the electrical structure of the microwave oven of this Example is shown typically. 19 is an external commercial power supply, 20 is a power switch, 21 is a rectifying ridge to rectify AC voltage, 22 is a choke coil for removing noise, and 23 is a smoothing of the pulsation rectified at a rectifying ridge 21. A smoothing capacitor for forming a DC power source, 24 is a switching element made of IGBT, 25 is a flywheel diode connected in parallel between the collector emitters of the switching element 24, 26 is a resonant capacitor connected in parallel to the flywheel diode 25, and 27 is a high frequency transformer. .

The high frequency transformer 27 boosts and outputs the voltage of the primary winding 28 and the primary winding 28 connected between the connection point of the choke coil 22 and the smoothing capacitor 23 and the connection point of the switching element 24 and the resonance capacitor 26. It consists of the secondary winding 29 and the heater winding 31.

The smoothing capacitor 23, the switching element 24, the flywheel diode 25, the resonant capacitor 26 and the primary winding 28 constitute an inverter circuit for converting from a commercial AC power source to a high frequency power source.

31 is a high voltage capacitor, 32 is a high voltage diode, and the high voltage capacitor 31 and the high voltage diode 32 are connected in series to form a half-wave voltage rectifier circuit. This half-wave voltage rectifier circuit is connected in parallel with the secondary winding 29 of the high frequency transformer 27, and supplies the high voltage half-wave rectified to the magnetron 8 to drive the magnetron. 33 is a cathode of the magnetron 8 connected to the heater winding 30, and 34 is a cathode of the magnetron 8 connected to the secondary winding 29.

35 is an oven thermistor for detecting the temperature in the heating chamber 7, 36 is a phase heater radiantly heated from the ceiling surface in the heating chamber 7, 37 is heating the air in the heating chamber to heat food from the rear of the heating chamber 7 by hot air circulation. The back heater, 38 is a lamp for illuminating the inside of the heating chamber 7, 39 is a current transformer that detects the current flowing in the magnetron, and 40 is a control circuit which controls the operation of the microwave oven 1 as a whole. The control circuit 40 includes a microcomputer.

In this configuration, the operation of a cooking course using a food placing tray, for example, an egg frying course, will be described. In this cooking course, first, the food placing tray 14 is preheated, and then, the food is placed and cooked.

First, a heating condition is input from the key input part 6 of the operation part 5 in step S1. For example, the temperature of the food placing tray 14 is set to 200 ° C. Then, only the food placing tray 14 is stored in the heating chamber 7 without placing the food, and the door 3 is touched. In step S2, it is determined whether the start button operation of the key input unit 6 has been performed. When it determines with operation in step S2, it transfers to step S3 and starts a heating operation. In step S3, the infrared sensor 16 detects the initial temperature of the food placing tray 14. In step S4, the preheating time T is set according to the initial temperature detected in step S3.

In step S5, the magnetron 8 is driven at a high output. In step S6, it is determined whether half the time of the set preheating time T has passed. The high output drive in step S5 is continued until the time T / 2 passes. If it is determined in step S6 that the time has elapsed, the process proceeds to step S7 to reduce the output of the magnetron 8 to the medium output and continue heating. In step S8, it is determined whether the preheating time T has elapsed. Step S7 is continued until this preheating time T has elapsed.

If it is determined in step S8 that the preheating time T has elapsed, the flow advances to step S9 to stop the heating, and a preheating termination notice is given by a buzzer or the like not shown, and the user is urged to place food on the tray 14 for food placing. In step S10, it is determined whether the door 3 is opened or closed, i.e., the door 3 is opened, the food is placed in the food placing tray 14, and the door 3 is closed again. In step S11, after judgment of step S10, it is determined whether the start button of the key input part 6 was operated. If it is determined that the operation has been performed, the process proceeds to step S12, where a cooking program such as a high power drive of the magnetron 8 is executed for 2 minutes. In step S13, it is determined whether or not the cooking operation of step S12 has ended. The cooking operation of step S12 continues until it is determined that such a step is complete. If it is determined in step S13 that the cooking operation has ended, the flow advances to step S14 to stop the heating operation, to notify the end of cooking, to notify the end of cooking, and to end the cooking operation.

In the above-mentioned step, the preheating process is shown from step S3 to step S9, and the step S12-step S13 has shown the cooking process.

And the preheating time T set in step S4 is set in consideration of reducing the output of the magnetron 8 on the way.

By this operation, as shown in FIG. 6, the temperature of the food tray 14 rises at the time of initial heating, but it does not raise uniformly the whole heat generating layer 18, but increases in the state which the nonuniformity rose in the temperature rise value. Then, when time T / 2 of half of the set preheating time T has passed, the output of the magnetron 8 will be reduced to medium output, and heating will continue. At this time, the temperature rise value of the food tray 14 becomes moderate, but the temperature rises by that amount, and heat transfer from the portion to the low temperature portion occurs, and the temperature rise in the heat generating layer 18 becomes almost uniform. For example, when fried eggs are cooked, some of them are completely crumpled while others are not finished.

According to the present invention, the temperature of the food stand is almost uniform, and the uneven cooking state can be suppressed.

Claims (1)

The heating chamber which food can hold, A magnetron that supplies microwaves to the heating chamber and microwaves the food; A food placing table which is housed in the heating chamber and has a heat generating member that absorbs the microwaves and generates heat; The preheating step of controlling the driving of the magnetron and preserving the food restraint by storing only the food restraint in the heating chamber to heat the heat generating member by microwaves in the magnetron; A control unit capable of carrying out baking cooking of the food having a cooking step of placing the food in the food placing table and storing the food in the heating chamber and performing heating cooking of the food by the heat of the heat generating member, In the first half of the preheating step, the control unit drives the magnetron at a high output to raise the temperature of the food stand to a high temperature, and in the second half of the preheating step, the temperature rise of the food stand is slowed so that the temperature of the food stand is moderate. And driving the magnetron at an output lower than the output of the first half of the preheating step in order to generate heat transfer from the portion to the low temperature portion to achieve approximately uniformity of the food stand temperature.

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