WO1983000375A1 - Microwave heater - Google Patents

Abstract

The level of a detection signal from a detection device (8) detecting variations in humidity or gas in a heating chamber (5) is selectively controlled according to the food being cooked, so that when the automatic cooking time of an egg must be set, the level is adjusted to a level lower than that corresponding to other automatic cooking times, and a correct signal is processed only when the detection signal is obtained continuously for a predetermined period of time, thereby controlling the heating time and carrying out the microwave cooking of the egg.

Description

 Rui Akira

 Title of invention

 High frequency heating equipment-technical field

 The present invention relates to a so-called automatic high-frequency heating device that cooks food by high-frequency heating, detects the cooking state of the food, and automatically determines the heating time.

 Background technique

The heating time of the food at high frequency depends on the initial temperature, volume, final temperature, specific heat, and high frequency energy absorption of the food to be heated. Conventionally, the method of setting the heating time of an i-microwave oven is as follows: (1) The user sets the time determined by the item and quantity of the heated food by a timer. Therefore, the initial temperature of the food is not taken into account, so cooking mistakes are likely to occur, and if the amount changes, the heating time must be calculated and set each time. -In recent years, in order to remedy these shortcomings, a sensor that detects the progress of speech in food and a control circuit mainly using a microcomputer have been used. Microwave ovens have been developed and are becoming the mainstream of microwave ovens in the market. The automatic microwave oven catches changes in relative humidity, food temperature, smell, gas, etc. caused by food heating with various sensors, and automatic cooking was possible only for certain items. However, microwave ovens could not automate eggs and other items that had previously been high in J9 failure rates. In the following, the principle of operation and the transition of cooking heating when cooking steamed rice bowl, which is a typical example of egg cooking, with a conventional automatic microwave oven will be described with reference to FIGS. 1 to 4.

 In Fig. 1, 1 is a transformer for driving magnetron 2,

5 3 and 4 are capacitors and diodes that constitute a rectifier circuit, 5 is a heating chamber, 6 is a heating object, and the moist air generated from the heated object 6 as a result of microwave heating is Air is exhausted from the exhaust port 7. Then, a humidity sensor 8 having the characteristics shown in Fig. 2 is installed in the air passage of the exhaust port 7, and the voltage at both ends of the resistor 9 connected in series with the humidity sensor is used as the humidity detection signal. . 1 O is a standard signal source, 1 1 is a preamplifier, 1 2 is a minimum value detection and holding circuit, and 13 is a subtraction circuit for detecting the rise in humidity from the minimum value. Outputs signal C proportional to A-B). 1 ⁴ voltage comparator der, a deviation signal C is compared with a reference voltage VtL ',趕tut the C is V li

1 5 output signal is generated. Reference numeral 15 denotes a drive circuit for the contact 16 which is turned on and off by the output signal of the voltage comparison circuit 14 and is turned on and off when the cooking is started and stopped. ST A is a cooking start signal.] 3, When ST A is input, the contact 16 is closed and opens when steam is detected. In other words, when the object to be heated 6 is heated by the high frequency generated from the magnetron 2 to generate steam, the humid air is exhausted. This air is detected by the humidity sensor 8, and the control circuits 11, 12, 13, 14, and 15 are used. When the rise of the detection voltage from the lowest value exceeds Vli, the contact 6 Opens and heating ends automatically.

25 However, according to the conventional barrel system described above, Was difficult.

 This is because egg cooking generally ends at a cooking temperature of 7 O'C to 8 O'C. If it is lower than this temperature range, it does not solidify at all and remains in a liquid state. Conversely, if it is too high, it solidifies in a foamy form and its tongue is bad.

 However, in the above temperature range, since the amount of generated steam is extremely small, various problems arise in determining and controlling the slight amount of steam as a detection signal. That is, the items to be heated in a microwave oven are unspecified in large numbers.D, for example, in the reheating of boiled fish, minimal steam is generated from the initial heating state from the tail, and the entire part is cold. The heating is completed. In addition, if the judgment is made with only a small signal, there is an increased danger that noise generated from the outside of the main body of the magnetron will enter the control circuit and malfunction.

Disclosure of the invention

 An object of the present invention is to solve the above-mentioned various problems by devising a simple control circuit and to automate egg cooking, which has been difficult.

In order to achieve the above object, the present invention provides a heating chamber for accommodating an object to be heated, a high-frequency generating means for high-frequency heating the object to be heated, and a detection for detecting a change in humidity, gas, odor, etc. in the heating chamber. Means, and a signal control means for controlling the high-frequency output, and a so-called processing item setting means, and a judgment level of the detection signal is selected according to a target preparation item. When the automatic heating of egg dishes is set, it is set lower than the detection signal judgment level at the time of other automatic heating, and the appropriate signal is set only when the above detection signal is obtained continuously. And control the heating time • The configuration is o

 BRIEF DESCRIPTION OF THE DRAWINGS

 FIG. 1 is a block diagram showing a conventional high-frequency heating device, FIG. 2 is a diagram showing characteristics of a humidity sensor, and FIG. 3 is a block diagram showing a high-frequency heating device according to one embodiment of the present invention. Fig. 4 shows the same characteristics.

 BEST MODE FOR CARRYING OUT THE INVENTION ''

 In FIG. 3, steam is generated from an object 6 to be heated in a heating chamber 5 t O by a high frequency generated from a magnetron 2 by a transformer 2, a capacitor 3, and a diode 4. The air containing the vapor is exhausted through the exhaust port 7. A humidity sensor 8 provided at the exhaust port 7 detects a change in humidity as a detection signal by a resistor 9]. 1 1 is a preamplifier, 12 is a minimum value holding circuit, 13 is a subtraction circuit, 14 is a voltage comparison circuit, and 15 is a relay drive circuit! ), It

15 The operation control is the same as in the above-described conventional example. · '

17 is a cooking item selection circuit, 18 is a reference voltage selection circuit, .19 is a reference voltage generation circuit, and 2O is a counter circuit having a timer function. In other words, the reference voltage Ii corresponding to each kind of food is stored and set in advance in the base voltage selection circuit! ), If other and 0 example, when the egg dishes were set to cooking item selection circuit ¹ 7 (IN) sends a very low voltage value, the sea urchin signal by the reference voltage generation circuit ¹ S occurs. Since the reference voltage Vii is at a low level, the voltage comparison circuit ¹⁴ sends a signal to the next power center circuit ² even if the humidity signal rise level is low by [3]. And the power converter circuit also serves as a timer circuit.] 3, continuous for a certain period of time Only when the above signal is counted, the signal is sent to the next contact drive circuit. That is, as shown in FIG. 4, even if an external noise signal is detected in the middle stage as shown by A or B in the figure, the signal does not come for _a certain period of time ta, so that the noise signal is Canceled and heating operation continues. Next, when the temperature of the egg preparation rises to about 7 O '(; to about 8 O'C, there is a slight change in humidity, and the detection signal continuously rises for t _a , thereby terminating the heating operation. Above, the specific example of humidity detection was explained, but it goes without saying that the same effect can be obtained by using a gas or odor sensor.o

 Industrial applicability '' As is clear from the above description, according to the present invention, in addition to the conventional automatic heating in general high-frequency heating equipment such as household electronic range, egg cooking ¾ Automatic heating of medium-temperature cooking is possible, and problems such as malfunction due to external noise are eliminated.

It is extremely useful because egg dishes, which had a high failure rate and were regarded as the most difficult dishes, can be easily cooked without failure. Note that the various ii-i circuits listed in this description can be processed by adding a program to one microcomputer that has been used in the past, and are almost inexpensive. Further, if the heating operation is performed by opening and closing the contacts of the relay, i) the operation is intermittent, and only when the contacts are opened, i.e., when the magnetron is not set, the control circuit determines the detection signal. However, the noise generated from the magnetron can be completely ignored, and it goes without saying that cooking can be performed with less uneven heating.

Claims

 • " The scope of the claims  A heating chamber for accommodating the object to be heated; a high-frequency generator for high-frequency heating the object to be heated; a detecting means for detecting changes in humidity, gas, etc. in the heating chamber; and a signal from the detecting means. Yo], high frequency (5) It has output control means for controlling the output and cooking item setting means, and the judgment level of the detection signal can be selectively controlled according to the set cooking item. Set the judgment level of the notation detection signal at the time of other general automatic heating to be 1 to smaller than the judgment level, and process it as an appropriate signal to only when the above detection signal is obtained continuously for a certain period of time, and control the heating time A high-frequency heating device characterized by performing  2. The high-frequency heating device according to claim 1, wherein the high-frequency generation means performs an intermittent operation, and performs a detection signal determination process only when the high-frequency generation means does not oscillate to control the heating time. 1 5 Thermal device. -- 0 5 One BU R £ 4  — 0