Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/66—Circuits
  • H05B6/68—Circuits for monitoring or control
  • H05B6/687—Circuits for monitoring or control for cooking
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/6447—Method of operation or details of the microwave heating apparatus related to the use of detectors or sensors
  • H05B6/6458—Method of operation or details of the microwave heating apparatus related to the use of detectors or sensors using humidity or vapor sensors

Definitions

• 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.
• 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.
• 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.
• 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.
• 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.
• 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
• the moist air generated from the heated object 6 as a result of microwave heating is Air is exhausted from the exhaust port 7.
• 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
• 13 is a subtraction circuit for detecting the rise in humidity from the minimum value.
• 1 4 voltage comparator der, a deviation signal C is compared with a reference voltage VtL ', ⁇ tut the C is V li
• 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
• 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.
• 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.
• 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.
• 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.
• 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
• FIG. 1 is a block diagram showing a conventional high-frequency heating device
• FIG. 2 is a diagram showing characteristics of a humidity sensor
• 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.
• 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
• 15 is a relay drive circuit!
• 17 is a cooking item selection circuit
• 18 is a reference voltage selection circuit
• .19 is a reference voltage generation circuit
• 2O is a counter circuit having a timer function.
• the reference voltage Ii corresponding to each kind of food is stored and set in advance in the base voltage selection circuit! )
• 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].
• 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.
• 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.
• 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

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Control Of High-Frequency Heating Circuits (AREA)
• Electric Ovens (AREA)

Priority Applications (1)

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Publications (1)

Family

ID=14626112

Family Applications (1)

Country Status (2)

Cited By (1)

Families Citing this family (2)

• 1981
  • 1981-07-20 JP JP11398381A patent/JPS5813937A/ja active Granted
• 1982
  • 1982-07-16 WO PCT/JP1982/000273 patent/WO1983000375A1/ja unknown

Non-Patent Citations (1)

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