JPS6037371B2 - microwave oven - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a microwave oven that has a food temperature sensor probe that detects the temperature of cooked food, and that detects an abnormal rise in temperature in the oven and stops the heating operation. .

Recently, some microwave ovens are configured to detect the temperature of cooked food using a food temperature sensor probe, and to stop the heating operation when the detected temperature reaches a preset cooking end temperature.

However, if a food temperature detection unit such as a food temperature sensor probe malfunctions, the temperature of the cooked food may rise abnormally, and in the worst case, the cooked food may carbonize, smoke, or catch fire. Therefore, in order to prevent the spread of danger due to these, we have developed a system that detects the temperature of the oven wall and disconnects the magnetron's power circuit when the detected temperature reaches a preset abnormality detection temperature. A thermal switch is used. However, the operating temperature of this oven thermal switch is generally set to the temperature at which ignition occurs in the oven, so even if the oven thermal switch operates, the inside of the oven may turn black. I can't put it down. Figure 1 shows the cooking end temperature (cooking end temperature) relative to the food temperature sensor probe when a thermal switch is installed on the oven wall as a conventional method.
For example, T, . , T, 2) and the abnormality detection temperature (operating temperature) T of the thermal switch.

In this example, assume that a food temperature sensor probe is used that cannot detect temperature at all due to a malfunction or the like. At this time, it is assumed that the user sets a cooking end temperature of about lukewarm water (approximately 5,000 degrees). However, as mentioned above, the food temperature sensor probe cannot detect temperature, so even if the temperature of the food reaches the set cooking end temperature, the heating operation will not be stopped and heating will not continue.
Eventually, the food will burn and start catching fire. However,
As mentioned above, the operating temperature of the conventional thermal switch is only one point, so the operating temperature cannot be lowered below the maximum cooking end temperature that can be set, and even in the above example, the abnormality detection temperature is high. The present invention has been made in view of the above circumstances, and an object of the present invention is to set the abnormality detection temperature in accordance with the setting of the cooking end temperature, so that the food temperature sensor probe, etc. When heating progresses beyond the cooking end temperature due to a malfunction in the detection part, the abnormality can be detected and the heating operation can be stopped before the food carbonizes, smokes, or ignites, thereby providing an extremely safe microwave oven. be.

First, to give an overview of the present invention, FIG. 2 shows the cooking end temperature T,
．． , T, 2 and the abnormality detection temperature L, , T, which is set in accordance with the setting.

As is clear from this figure, the abnormality detection temperature changes in accordance with the value of the cooking end temperature that is set. Naturally, the abnormality detection temperature is higher than the cooking end temperature, but by considering the size and heat distribution of the food that can be cooked in the microwave oven, the abnormality detection temperature can be set to an appropriate value in advance. In the conventional example shown in Figure 1, in order to detect an abnormality, the temperature must always rise to a certain high temperature, so when an abnormality is detected, most of the food will be carbonized, and there will be smoke inside the oven. It has to get dirty. On the other hand, in the present invention shown in FIG. 2, the abnormality detection temperature also changes depending on the setting of the cooking end temperature. It is detected by An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, 11 is a microwave oven, and a magnetron 12 is provided on one side wall of the oven.

High frequency waves from the oven 12 are guided into the oven 11 to heat and cook the cooked food 13 placed in the oven 11. , the magnetron 12 has its power supply circuit 1
4, and this power supply circuit 14 is connected to an AC power supply 16 via a normally open contact 15a of a contactor 15. On the other hand, reference numeral 17 is a food temperature sensor probe, and the temperature sensing portion thereof is inserted into the food 13 to detect the temperature of the food 13. Reference numeral 18 denotes an oven temperature sensor, such as a thermistor, which detects the temperature inside the oven 11, and is provided at a predetermined location inside the oven 11. Thus, the food temperature sensor probe 17 and thermistor 18 are each connected to a temperature determination section 19. The temperature determination unit 19 determines each temperature detected by the food temperature sensor probe 17 and thermistor 18, and determines whether or not each temperature matches the cooking end temperature and abnormality detection temperature set by the temperature setting unit 20. It makes a determination and outputs a heating stop signal when they match. Above temperature setting section 2
This is for setting the cooking end temperature (and abnormality detection temperature), and is provided on the operation panel of a microwave oven, for example. In this case, as described above, the abnormality detection temperature is automatically set following the setting of the cooking end temperature as shown in FIG. Thus, the heating stop signal output from the temperature determination section 19 is supplied to the control section 21 . This control unit 21 includes a cooking start switch 22
The heater 15 is controlled in response to a signal from the heating stop signal or the heating stop signal. Next, the operation in such a configuration will be explained.

First, a desired cooking end temperature is set using the temperature setting section 201. At this time, as described above, the abnormality detection temperature for the cooking end temperature is also set. For example, as shown in FIG. 2, when a cooking end temperature T, 2 is set, an abnormality detection temperature L2 for that temperature T, 2 is automatically set in accordance with it. Next, food temperature sensor probe 17
Insert the temperature sensing part into the food 13 and press the cooking start switch 22.
By turning on, the control unit 21 energizes the contactor 15 to close its normally open contact 15a. Therefore, the magnetron 12 is energized and operates to oscillate, and the heating operation of the food 13 is started. The temperature of the food 13 due to this heating operation is detected by the food temperature sensor probe 17,
The temperature is supplied to the temperature determination section 19. The temperature determination unit 19 determines the temperature detected by the food temperature sensor probe 17 and determines whether it matches the cooking end temperature set by the temperature setting unit 20 or not. As a result, when the two temperatures match, the temperature determination section 19 outputs a heating stop signal. As a result, the control unit 21 deenergizes the contactor 15 and connects the magnetron 12.
Turn off the power to the unit and stop the heating operation. However, if the food temperature sensor probe 17 is out of order and temperature detection is impossible, the temperature determination section 19 is not supplied with the detected temperature of the food 13 from the food temperature sensor probe 17. Even if the temperature of food No. 13 reaches the cooking end temperature, the heating stop signal is not output, so food No. 13
heating continues.

However, at this time, the thermistor 18 detects the temperature inside the oven 11 and supplies it to the temperature determination section 19. Therefore, the temperature determination unit 19 determines the detected temperature from the thermistor 18 and determines whether it matches the abnormality detection temperature set by the temperature setting unit 20. As a result, when the two temperatures match, the temperature determination unit 19 outputs a heating stop signal, and the control unit 21 deenergizes the contactor 15 to quickly cut off the power to the magnetron 12 and stop the heating operation. As described in detail above, according to the present invention, by configuring the abnormality detection temperature to follow the setting of the cooking end temperature, the abnormality detection temperature can be set, so that the cooking end temperature can be set even if the food temperature detection section such as the food temperature sensor probe malfunctions. When the heating progresses to the above point, an abnormality can be detected and the heating operation can be stopped before the food carbonizes, smokes, or catches fire, making it possible to provide an extremely safe microwave oven.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between the conventional setting of the cooking end temperature and the abnormality detection temperature, and Fig. 2 is a diagram showing the setting of the cooking end temperature and the abnormality detection set in accordance with the setting of the cooking end temperature to explain the outline of the present invention. FIG. 3, a diagram showing the relationship with temperature, is a configuration diagram showing an embodiment of the present invention. 11... Oven, 12... Magnetron, 13...
... Cooked food, 17 ... Food temperature sensor probe, 18 ... Thermistor (oven temperature sensor), 1
9...Temperature determination section, 20...Temperature setting section. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An oven, a heating means for heating the cooked food placed in the oven, a food temperature sensor probe for detecting the temperature of the cooked food placed in the oven, and an oven temperature sensor for detecting the temperature inside the oven. a sensor, a temperature setting section that sets an abnormality detection temperature in accordance with the cooking end temperature when the cooking end temperature is set, and the cooking end temperature set by the temperature setting section and the detection temperature of the food temperature sensor probe. temperature determination means for determining whether or not the temperature determination means and the heating means match, a control means for stopping the operation of the heating means when the temperature determination means and the heating means are determined to match, and temperature determination means for determining whether or not the temperature determination means and the heating means match; A microwave oven characterized by comprising temperature determining means for determining whether or not the temperatures detected by a temperature sensor match, and a control means for stopping the operation of the heating means when the temperature determining means determines that they match. .