JPH0230410B2 - JIDOKANET SUCHORIKI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control device for an automatic heating device equipped with a sensor.

BACKGROUND TECHNOLOGY In recent years, various heating devices have rapidly become intelligent based on electronic control, and automatic heating devices that use various sensors to detect the heating state of objects to be heated and automatically control heating have become It has spread quickly.

With this system, the control unit uses a sensor to automatically terminate heating without the user having to set the heating time, output, heating temperature, etc. as in the past, and the amount of the object to be heated and the initial Microwave ovens and other devices that require consideration of temperature and other factors have become much easier to operate and can heat with fewer failures.

As such prior art, there is
There is a publication number 134951. This detects the change in humidity generated from the object to be heated, and determines the point at which steam is generated when it reaches a certain set value. The total heating time is the sum of the heating time T ₁ to reach that point and the product RT ₁ of a separately determined coefficient R specific to the heated object.

This is an example of automatic heating control using a so-called humidity sensor, but it is also an extremely effective control method for a so-called gas sensor that reacts with steam, alcohol, and carbon dioxide.

Problems to be Solved by the Invention However, this method also had the following difficulties. That is, in a low-temperature environment, the amount of water vapor that can be contained in the air, that is, the amount of saturated vapor, is very small. For example, in an environment of 4°C, it is 5g/Kg. On the other hand, as a result of experiments, it was confirmed that approximately
It has been found that it is good to set the point where 30 g/Kg of steam is generated as the steam generation point. However, as mentioned above, in an environment of 4℃ and 50% RH, the saturated state is reached when only 2.5g/Kg of steam is generated from the heated object, so any more steam generated will condense and drain into the heating chamber. It simply adheres to the wall surface and does not reach the sensor that detects water vapor, making it impossible to obtain the steam generation point.

FIG. 1 is an example clearly showing such a situation. FIG. 1a is a diagram showing changes in the amount of steam generated from the object to be heated. FIG. 1b is a diagram showing changes in relative humidity within the heating chamber. The amount of steam generated from the heated object increases as it is heated. However,
The relative humidity in the heating chamber reaches 100% when the amount of steam generated from the heated object reaches 2.5g/Kg (example in an environment of 4℃ and 50% relative humidity), and from then on,
Changes in relative humidity cannot be obtained. Therefore, the steam generation point cannot be detected. This makes it impossible to determine the total heating time.

Although the above example shows an example at a low temperature, the same can be said in a normal environment of 20°C. For example, in an environment of 20°C and 80% RH, this environment contains 13g/Kg of steam. However, the amount of saturated steam at 20°C is 15g/Kg.
Therefore, the saturated state is reached when only 2 g/Kg of steam is generated from the heated object. As can be seen, a problem similar to the problem at 4° C. described above occurs.

The present invention solves the above-mentioned conventional problems and provides an automatic heating cooker having a sensor control system that realizes stable and reliable automatic heating without depending on the surrounding environment.

Means for Solving the Problems In order to achieve the above object, the automatic heating cooker of the present invention includes a second heating source that increases the temperature inside the heating chamber, and is powered by a first heating source that supplies high-frequency energy. A control section for supplying power to the second heating source is provided before the heating.

Effect When power supply to the first heating source is started, the temperature in the heating chamber has already been increased by the second heating source, thereby making it possible to sufficiently increase the amount of saturated steam. Therefore, even if a large amount of steam is generated, no dew condensation occurs, and the most desirable steam generation point can be detected.

Embodiment An embodiment of the present invention will be described below based on the drawings.

FIG. 2 is a perspective view of the automatic heating device according to the present invention. A door body 2 is attached to the front surface of the main body 1 so as to be openable and closable, and an operation panel 3 is arranged. On this operation panel 3, there are provided at least a keyboard 4 for selecting a heating sequence depending on the object to be heated, and a display section 5 for making various notifications.

In FIG. 3, reference numeral 6 denotes a heating chamber, in which an object to be heated 7 placed therein is heated by high frequency energy oscillated from a magnetron 8. 9 is a fan motor;
While cooling the magnetron 8 and the like that are the first heating source, ventilation air 12 is blown into the heating chamber through the ventilation duct 10 and the ventilation opening 11. Exhaust air 14 containing water vapor 13 emitted from the object to be heated 7 is discharged through the exhaust port 1
5 into an exhaust duct 16.

A heater 17, which is a second heating source, is provided within the air duct 10. The exhaust duct 16 is provided with a humidity sensor 18 for detecting humidity and a temperature sensor 19 for detecting temperature.

FIG. 4 shows a block diagram of the electric circuit and control section of the embodiment. 21 is an A/D converter that converts the value of the temperature sensor into a digital quantity. 22 is A/D
Depending on the value of the converter 21, a corresponding time is read from the time register 22 and set in the timer 24. The timer 24 counts down and outputs a signal when it reaches 0. 25 is a main circuit relay. 26 is a heater control relay. 27 is a relay that controls power supply to the magnetron 8.
28 is a high voltage transformer, 29 is a high voltage capacitor, 3
0 is a high voltage diode.

The operation of the above configuration will be explained below.

When the start signal is input, the total heating time control circuit starts control and outputs each relay drive signal R _S. This causes the relay 25 to operate and the fan motor 9 to operate. On the other hand, the signal from the temperature sensor 19 is input to the A/D converter 21 . A/D converter 2
In response to the signal 1, the time selector 22 reads the time from the time register 23 and sets the time in the timer 24. The time selector 22 has a function of outputting 0 when the temperature inside the heating chamber is at the highest level. Timer 24 counts down to 0
or time selector 31 to 0
outputs a signal when input, and in the former case,
Power supply to the second heat source is stopped and power supply to the first heat source is started, and in the latter case, power supply to the first heat source is started immediately after the start. by the way,
The time determined as follows is input into the time register 23.

The initial temperature in the heating chamber is divided into at least two levels,
Find the saturated vapor amount at the highest temperature for each separated level. For example, 0°~15°C, 15°~30°C,
If it is classified into four levels: 30° to 45°C and 45°C or higher, 15°C, 30°C, and 45°C are the highest temperatures, and their saturated steam amounts are 11g/Kg and 27g/Kg, respectively.
Kg, calculated as 64g/Kg. In the case where the steam generation point is determined as the point where 30g/Kg of steam is generated from the object to be heated 7, the temperature at which the saturated steam amount is the value of 30g/Kg added to the saturated steam amount at the maximum temperature is determined. demand. This temperature is calculated from the psychrometric diagram.
The temperatures are found to be 37℃, 43℃, and 51℃. Furthermore, the time required for the heater to reach this determined temperature is determined and this time is input into the time register 23.

FIG. 5 shows a time chart of the above action.

As described above, according to this embodiment, the following effects can be obtained.

The environment in which a cooker is normally used ranges from 0°C to
The temperature is 35℃ and the humidity is about 10% to 95%RH. Therefore, if the temperature in the heating chamber 6 at the start of cooking is raised to the predetermined temperature as described above, the steam generation point can be accurately detected without worrying about saturation. .

FIG. 6 shows another embodiment of the present invention, and is a block diagram of a control section that controls power supply to the heating source and an electric circuit diagram of the heating source. Reference numeral 20 denotes a total heating time control circuit, which starts control in response to a start signal, receives a signal from the humidity sensor 18 while power is being supplied to the first heating source, detects the steam generation point, and determines the total heating time. 21 is an A/D converter that converts the signal from the temperature sensor 19 into a digital quantity. Reference numeral 31 denotes a temperature selector, which reads and outputs the temperature from the temperature register 32 in response to a signal from the A/D converter 21 at the start of cooking. 33 is a comparator which compares the signal from the A/D converter 21 and the signal from the temperature selector when power is being supplied to the second heating source, and outputs a signal when the signal from the A/D converter 21 becomes higher. Output and also hold.

The operation of the above configuration will be explained below.

When the start signal is input, the total heating time control circuit starts control and outputs the relay drive signal R _S.
This causes the main circuit relay 25 to operate and the fan motor 9 to operate. On the other hand, since the temperature of the heating chamber 6 is initially low, the output of the comparator 33 is 0, and the heater control relay 26 is activated by the AND of the negated signal and the R _S
Power is supplied to a heater 17 which is a heating source. Also,
At the same time, the signal from the temperature sensor 19 is A/D converted and input to the temperature selector 31. The temperature selector 31 reads and holds the temperature from the temperature register 32 in response to a signal from the A/D converter 21. The data in the temperature register 32 read out by the temperature selector 31 is determined in advance by the following method.

As described in the first embodiment, the temperature at which the temperature must rise from the heating at the start of cooking is determined. Therefore, the temperature is input into the temperature register 32.

By the way, when the temperature at the start of cooking was at the highest level of the sorted level (45℃ in the above example)
above), the temperature selector 22 is the A/D converter 21
A signal is output from the comparator 24 to more reliably output low data, and power is not supplied to the second heating source but to the first heating source. The temperature in the heating chamber 6 rises due to power being supplied to the heater 17, and when the A/D converted value of the signal from the temperature sensor 19 exceeds the temperature held in the temperature selector 22, the comparator 24 outputs a signal. Output and retain. As a result, the heater control relay 26 is turned off, and the magnetron control relay 26 is turned off.
7 operates and starts detecting humidity.

As described above, according to this embodiment, the following effects can be obtained.

Since power is supplied to the first heating source after the temperature of the heating chamber 6 always reaches a predetermined temperature, even if the power applied to the heater fluctuates, the steam generation point can be maintained without becoming saturated. Can be detected.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) Since the amount of steam does not reach the saturated steam level in any environment in which a cooking device is normally used, the steam generated from the heated object can reach the humidity sensor without condensing, and the steam generation point It can be detected accurately and the total heating time can be determined.

(2) Since the temperature inside the heating chamber is raised at the start of cooking, water droplets adhering to the walls of the heating chamber can be dried and expelled from the heating chamber, thereby preventing errors when detecting humidity. can.

[Brief explanation of drawings]

Figures 1a and b are characteristic diagrams showing problems with conventional automatic heaters, Figure 2 is an external perspective view of an automatic heating cooker that is an embodiment of the present invention, and Figure 3 is a front view of the same cooker. 4 shows a control circuit diagram of the device, FIG. 5 shows an output waveform diagram of a main part of the circuit, and FIG. 6 shows a control circuit diagram of another embodiment of the present invention. 6... Heating chamber, 7... Heated object, 8... Magnetron, 13... Steam, 17... Heater, 18
...Humidity sensor, 19...Temperature sensor.

Claims (1)

[Claims] 1 a heating chamber that stores an object to be heated, a first heating source that supplies high frequency energy to the heating chamber, and a second heating source that increases the temperature within the heating chamber;
a sensor that detects water vapor generated from the object to be heated when power is supplied to the first heating source; and a sensor that starts supplying power to the second heating source before starting power supply to the first heating source. and a control section that determines the total heating time based on the signal from the sensor.