JPH02290430A - Heating cocking apparatus - Google Patents

Abstract

PURPOSE:To prevent a foodstuff to be heated from rising at its temperature more than required even if a temperature sensor is not dipped in an foodstuff to be heated by providing a control circuit for turning OFF a heat source if the temperature to be detected by the sensor is a predetermined value or less when a predetermined period of time is elapsed after the heat source is turned ON. CONSTITUTION:A temperature sensor 22 is connected in series with a resistor 32 at the output of a constant-voltage circuit 31 to apply its partial voltage to the A/C converter 27a of a microcomputer 27, which turns OFF a halogen lamp 3 by its judgement in any of cases in which insertion of the plug 23 of the sensor 22 to a jack 21 is inaduertently forgotten, the sensor 22 is disconnected, and the jack 21 is improperly connected. For example, if an ambient temperature is 5 deg.C, amount of oil is 120% of rated capacity, and a power source voltage is 95% of a rated value, it judges that the mounting state of the sensor 22 is abnormal if the detecting temperature of the sensor 22 is 45 deg.C or lower from when 4min is elapsed after the energization of the lamp 3 is started to turn OFF the lamp 3. Thus, it can effectively prevent oil from rising to a temperature of an ignition point.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a cooking device that heats a pot containing a food to be cooked using a heating source.

(Prior art) Conventionally, when heating an object, such as a pot containing porridge, using a heating source, a temperature sensor is immersed in oil and the output of the heating source is controlled while the temperature of the oil is detected by the temperature sensor. The idea is to keep the temperature inside the pot within a predetermined temperature range by controlling the temperature.

(Problem to be solved by the invention) However, if you forget to immerse the temperature sensor in the ura in the pot and turn on the heating source, the temperature sensor will detect the room temperature, and the temperature of the ura will be adjusted to a predetermined value. Since it is difficult to maintain the temperature within the range, there is a drawback that the temperature of the oil becomes higher than necessary and is heated to the ignition point. Even if a temperature sensor is immersed in oil, if some kind of inmate rises up to 7 degrees and comes out from the surface of the oil, the same drawbacks as described above will occur.

Therefore, an object of the present invention is to provide a heating cooker that can reliably prevent the temperature of the object to be heated from becoming higher than necessary even when the temperature sensor is not immersed in the object. .

[Structure of the Invention] (Means for Solving the Problems) The present invention is a device for heating a pot containing an object to be heated using a heating source provided in the main body of the rice cooker, in which the object to be heated in the pot is heated. A temperature sensor that is immersed is provided, and a control circuit is provided that controls the heating source based on temperature information obtained by the temperature sensor, and the control circuit controls the temperature sensor when a certain period of time has passed after the heating source is turned on. The heating source is turned off when the detected temperature is below a predetermined value.

(11) According to the above-mentioned method, if the user forgets to immerse the temperature sensor in the heated object, or if the temperature sensor immersed in oil floats up from the surface of the pool for some reason. When the heated object goes outside, the temperature sensor does not detect the actual temperature of the heated object because the temperature of the heated object is not transmitted to the temperature sensor. Ensure that the temperature of the IF becomes higher than necessary. can do.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 10.

First, as shown in Fig. 1, the electric cooking device main body 1 is formed into a flat rectangular box shape and is set on the top plate A of the cooking table, and heating units 2 are arranged at two places on the left and right inside. It is set up. These heating units!・As shown in FIG. 3, 2 is a bottomed lower insulation by sandwiching a heater, that is, a halogen lamp 3 as a heating source, between two oblong upper and lower insulation bodies 4 and 5, each having a number of bells, for example four. The body 5 is attached to the body 1 by the saucer 6.
It is fixed to the inner bottom surface of the The upper surface of the upper heat insulator 4 of each heating unit 2 is covered with a translucent top plate 7 made of a piece of heat-resistant glass or the like.
The top plate 7 is in close contact with the upper heat insulator 4 to seal the inside of the heating unit 2.

The temperature inside this sealed heating unit 2, and therefore the ambient temperature of the halogen lamp 3, is detected by a thermostat 8 as temperature detection means. This thermostat 8 includes a heat sensitive part 9 which is formed by disposing a metal rod (not shown) that expands and contracts according to temperature changes in a metal outer tube, and a switch that is turned on and off by the expansion and contraction of the metal rod of this heat sensitive part 9. The heat sensitive part 9 is arranged inside the heating unit 2, and the switch part 10 is arranged outside the heating unit 2. Note that this thermostat 8 is designed to turn off at a temperature of 750° C. or higher.

Further, operation panels 11 are provided on the left and right sides of the front surface of the main body 1. On the left half of this operation panel 11, as shown in FIG. ．． M! "Yari upJ" and "Input do
Switches 14 and 15 for wnJ and switches 16 and 17 for "tempura mode entry deadline" and "oil temperature adjustment" are provided, as well as a plurality of switches for displaying the magnitude of input to the halogen lamp 3. A light emitting diode 18 and light emitting diodes 19 and 20 are provided for displaying oil temperature and tempura mode human/off. A plug 21 is provided at the rear left corner of the main body 1, and a plug 23 of a temperature sensor 22 is removably connected thereto. The pot 24 placed on the top plate 7 is provided with a holder 25 for holding the temperature sensor 22.

The various switches 12 to 15 and the light emitting diode 18 described above are connected to the operation panel 1 in a one-to-one relationship with each heating unit 2.
However, for convenience of explanation, only the left heating units 1 and 2, which are operated by switches provided on the left half of the operation panel, will be described.

The electrical configuration of the control circuit that controls the heating unit 2 on the left side of this electric cooker is as shown in FIG. 4, and the four halogen lamps 3 of the heating unit 2 are connected in parallel to the power source 26. The three groups of halogen lamps are controlled to be turned on and off by a microcomputer 27.

The microcomputer 27 controls various electrical parts included in the electric cooking device main body 1, and receives signals from the thermostat 8, various switches 12 to 17, temperature sensor 22, etc., and responds to the human input signals. By turning off the power to the light emitting diodes 18 to 20 and controlling on/off the triax 28 connected in series with the halogen lamp 3g via the drive circuit 30, the power is turned off to the three groups of halogen lamps. The output of halogen lamp 3 (heat generation 2) during the energization period is
Control is performed by phase control of the triac 28.

This temperature sensor 22 has a resistor 32 connected to the output of the constant voltage circuit 31.
are connected in series, and the partial voltage is sent to the A-D converter section 27a of the microcomputer 27). However, when the ambient temperature exceeds 90℃, switching transistor 3
By turning on resistor 3 and connecting resistor 32 and resistor 34 in parallel, the range of detected temperatures is expanded. In this case, the resistor 32 is set to 100 kΩ, and the resistor 34 is set to 3
It is set to kΩ.

For example, a thermistor with negative temperature characteristics as shown in FIG. 7 is used as the temperature sensing element of the temperature sensor 22, but this has a resistance of 375 kΩ when the ambient temperature is 20°C,
It is set to 9 7 5 1 cΩ at ℃.

The main flowchart of the microcomputer 27 is shown in FIG.

Next, the operation of the above configuration will be explained. First, when performing normal continuous heating on the object to be heated, that is, when selecting the "continuous heating mode", the plug 23 of the temperature sensor 22 is removed from the jack 21, and only the "person" switch 12 is turned on. let In this case, the human power applied to the halogen lamp 3, which is the heating source, is adjusted by operating the switches 14 and 15. 1! The adjusted state is displayed on the light emitting diode 18. In this way, "continuous heating mode"
When you select , the microcomputer 27 displays (a) (b)
, (H), and (T), the halogen lamp 3 is operated to be continuously energized. When this "continuous heating mode" is selected, if the plug 23 of the temperature sensor 22 is connected to the jack 21, step
It is judged as rYJ, an "error" occurs, and the halogen lamp 3 is turned off. Also, during continuous heating, Jack 21
Similarly to the case described above, when the plug 23 of the temperature sensor 22 is connected to , rYJ is determined in step (h), resulting in an "error".

Next, when frying tempura using oil as the food to be heated, a "temperature control mode" using the temperature sensor 22 is selected.
(Tempura mode) is selected, and the effect in this case will be described below. First, connect the plug 23 to the jack 21 and attach the temperature sensor 22 to the holder 25 of the pot 24 containing oil.
Set to .

Next, use the switch 16 to select "tempura mode" so that the light emitting diode 20 lights up, and use the switch 17 to select the oil setting temperature (160°C or 18°C).
0° C.) is selected, the light emitting diode 19 corresponding to the selected temperature is turned on, and the "person" switch 12 is turned on in this bad condition. Then the microcomputer 27
When passing through step (a) and moving to step (b), it is determined that rYJ, and the process moves to step (c). When the plug 23 is not connected to the jack 21, the microcomputer 27 is connected to the human input terminal because the resistance between the input terminal f27a-+ of the A-D converter section 27a and the human input terminal 27a-2 is infinite. 2 7 a -2 becomes the same voltage as the input terminal 2 7 a - 3, but such a state occurs when the ambient temperature is 0 according to the temperature characteristics of the thermistor shown in Figure 7.
'C. Therefore, when moving to this step (c), the microcomputer 27
By determining whether the signal given to the A-D converter section 27a is below 0° C., it is possible to determine whether a sensor is inserted into the jack. If rYJ is determined in this step, the process moves to step (work), but the plug 23 of the temperature sensor 22 is
If you forget to add 1, it will be judged as rNJ and an "error" will occur.
Therefore, the halogen lamp 3 is not energized.

The "ON" switch 12 is not activated by an instantaneous ON operation, but is enabled and activated if the ON operation is continued for 700 ms, for example. A buzzer 35 as an alarm is connected to the microcomputer 27 via a drive circuit consisting of a transistor 34, and as shown in FIG. 700 to be activated
After ms has elapsed, the ringing is stopped. Therefore, it is only necessary to confirm that the buzzer 35 has stopped ringing and then finish the ON operation. Then, steps (a) and (c) above are performed by buzzer 3.
This is done based on the completion of the ringing in step 5. r in step (c)
When it is determined that it is YJ, the halogen lamp 3 is turned on. In addition, if rNJ is determined in step (c), after the above-mentioned 700 ms ringing is completed, the same Fig. 6 (b)
As shown in FIG. 3, the alarm rings and stops five times in succession at intervals of 80 ms to notify the user of the abnormal condition, and the halogen lamp 3 is no longer energized. This notification of an abnormal state is performed in the same way even if an "error" occurs in any step.

In either the case where the plug 23 is forgotten to be attached to the jack 21 as described above, or the case where the temperature sensor 22 is disconnected or the plug 23 is poorly connected to the jack 21, the A-D converter section 27a of the microcomputer 27 Since the states of the signals given to the two terminals are the same, determination is also made in step (c) if the temperature sensor 22 is disconnected or if the plug 23 is poorly connected to the jack 21.

The abnormal state described above when the switch 12 is turned on is determined in step (c), but subsequent abnormal states are also determined in steps (h) and (c) in accordance with step (c). By making a judgment based on these steps, the plug 23 is connected to the jack 2 while the pot 24 is being heated in accordance with the above-mentioned abnormal condition.
It is also possible to judge if it deviates from step 1, and in such a case, rNJ can be performed in any of steps
This is determined to be an "error" and the halogen lamp 3 is turned off.

When 4 minutes have elapsed after turning on the halogen lamp 3 in step (E), the process moves from step (E) to step (force), and the temperature detected by the temperature sensor 22 is higher than or equal to the first set temperature, that is, 45°C. This temperature is determined based on the transition of the detected temperature when the temperature sensor 22 is normally attached to the wh24. The characteristic curve shown in Fig. 8 is when the room temperature is 5°C, the amount of water is 120% of the constant capacity of the pot 24, and the power supply voltage is 95% of the rated value, that is, the state where the temperature rise rate generally considered is the lowest. This shows the relationship between the temperature of Noura and the temperature detected by the temperature sensor 22. Under these conditions, the temperature detected by the temperature sensor 22 after 4 minutes has passed since the start of electricity supply is 50°C, so the halogen lamp 3
When 4 minutes have passed after the start of energization, the H degree sensor 22
If the loading condition of the temperature sensor 22 is normal, it should always be 50'C or higher, so if it does not reach 45℃, which is 5℃ lower than this, there is an abnormality in the loading condition of the temperature sensor 22. If the judgment is rNJ, an "error" occurs and the halogen lamp 3 is turned off.

This step (force) is 4 after energizing the halogen lamp 3.
After minutes have elapsed and it is determined that the temperature is rYJ in step (e), thinning is continued until it is determined that the set temperature has been reached (rYJ) in step (ke). That is, from the time when 4 minutes have passed after the start of electricity supply to the halogen lamp 3, the time t when the detected temperature of the temperature sensor 22 reaches the set temperature T (the oil temperature is 160° C. or 180° C.)! The temperature change up to this point is always 45°C or higher, as shown in Figure 10, so if the temperature drops to 45°C or higher during this period, there is an abnormality such as liil in the mounting state of the temperature sensor 22. If the judgment is rNJ, an "error" occurs and the halogen lamp 3 is turned off.

In step (g), it is determined whether 12 minutes or more have passed since the halogen lamp 3 was energized.

This step (g) is continued until rYJ is determined in step (k). This 12 minutes is
It is determined based on the transition of the detected temperature when the temperature sensor 22 is normally attached to the w424. That is,
The characteristic curve shown in Figure 9 shows that the room temperature is 5℃ and the amount of ura is 24℃.
When the rated capacity is 120% and the power supply voltage is 95% of the rated capacity,
In other words, it indicates the temperature of the oil when the rate of temperature increase generally considered is the lowest, and under these conditions, 11 minutes after the start of electricity supply
Since the temperature of the ura reaches the set temperature (160°C) when 0 seconds have passed, if the temperature sensor 22 is in a normal state when the temperature is heated for 12 minutes after the start of energization, it should definitely reach 160°C or higher. If the set temperature is not reached even after 12 minutes have passed after the start of energization, it is determined that there is an abnormality such as lIil in the status of the temperature sensor 22, and when the determination is rNJ, an "error" occurs. halogen lamp 3
Turn off.

In step (T), it is also determined whether 12 minutes or more have elapsed since the halogen lamp 3 was energized.

The room temperature is 35℃, the amount of oil is 8096, which is the rated capacity of pot 24,
The set temperature (160℃) when the power supply voltage is 120% of the rated value, that is, when the temperature rise rate generally considered is the highest.
Even if the temperature sensor 22 is heated continuously for 12 minutes, the temperature of the oil remains at 340°C, which does not reach the temperature of 370°C, which is the ignition temperature of the oil. If continuous heating is detected and the halogen lamp 3 is turned off, the oil will not reach the ignition temperature.

When it is determined in step (k) that the temperature detected by the temperature sensor 22 has reached the set temperature T at time t, the process moves to step (k), and the temperature detected by the temperature sensor 22 reaches the second temperature.
It is determined whether the temperature is higher than the set temperature, that is, 110°C. When the temperature sensor 22 reaches the set temperature T at time 1, the temperature change when the temperature sensor 22 is normally installed is always 110°C or more as shown in FIG. When the temperature reaches 110 degrees Celsius or higher, it is determined that there is an abnormality in whether the temperature sensor 22 is installed or not, and when the determination is rNJ, an error J occurs and the halogen lamp 3 is turned off. .

If it is judged as "N" in step (S), the halogen lamp 3 is turned on in step (S), and if it is judged as "Y", the halogen lamp 3 is turned off in step (C). The oil inside is maintained at a predetermined temperature set by switch 17.

Although not described in the flowchart of the microcomputer 27, when the "off" switch 13 is operated,
Regardless of whether "continuous heating mode" or "temperature control mode" is selected, the halogen lamp 3 is turned off after steps (H), (E), (KE), and (S) are performed, for example. .

In this way, according to this embodiment, the plug 23 is connected to the jack 2.
If you forget to attach the temperature sensor 22 connected to 1 to the holder 25 of the pot 24 and the temperature sensor 22 is not immersed in oil, the temperature sensor 22 will detect the temperature of the surrounding outside air. There will be almost no temperature rise, but in such a case, it will be determined that 4 minutes have passed since halogen lamp 3 was turned on in step (E), and rNJ will be determined when the step (force) is shifted. Since the halogen lamp 3 is turned off when an "error" occurs, it is possible to reliably prevent the temperature of the heated object from becoming higher than necessary in such a case, and the temperature of the oil reaches the ignition point. rising=11 is reliably prevented.

FIG. 11 shows another embodiment of the present invention, in which the jack 21 has two contacts 21a and 2l that contact the plug 23.
One of the contacts 21a is biased in the direction of arrow G by a spring 21c. For this,
FIG. 11 shows the plug 23 removed from the jack 21 (
In the state shown in b), the contacts 21a and 21b are short-circuited, and the resistance value between them becomes 0Ω. In the embodiment described above, the input terminals 27a and 27 of the A-D converter section 27
When the resistance between a and 2 is infinite, step (c)
, (h) and (c), the halogen lamp 3 is turned off by determining rNJ, respectively. However, in this embodiment, the human power terminal 2 7 a . −
When the resistance between 1 and 27 3-2 is 0, if the halogen lamp 3 is turned off by determining rNJ in steps (C), (C), and (S), the result is the same as in the above embodiment. It has the following effects.

[Effects of the Invention] As is clear from the above description, when the user forgets to immerse the temperature sensor in the object to be heated,
dc because the temperature of the heated object is not transmitted to the temperature sensor.
Although the iR temperature sensor is not detecting the actual temperature of the object to be heated, if the temperature detected by the temperature sensor is below a predetermined value after a certain period of time has elapsed after the heating source is turned on, the temperature sensor does not detect the actual temperature of the heated object. Since the power source is turned off, it is possible to reliably prevent the temperature of the object to be heated from becoming higher than necessary in such a case, which is an excellent effect.

[Brief explanation of the drawing]

1 to 10 show an embodiment of the present invention,
Figure 1 is a partially cutaway perspective view, and Figure 2 is an enlarged view of the operation panel! E blood diagram, Figure 3 is a sectional view taken along the line ■-■ in Figure 1, and Figure 4 is the electrical t1-! of the control circuit.
Fig. 5 is a diagram showing the flowchart of 11 Godouji,
Figure 6 is a diagram showing a timing chart, Figures 7 to 1
0 is a diagram showing temperature characteristics, and FIG. 11 is a sectional view showing another embodiment of the present invention. In the drawing, 1 is the heating cooker body, 3 is a halogen lamp (heat source), 21 is a jack, 22 is a temperature sensor, 23 is a plug, 24 is a pot, 25 is a holder, 27 is a microcomputer, 35 is a buzzer (alarm)

Claims (1)

[Claims] 1. In a device that heats a pot containing an object to be heated using a heat source provided in the cooking device, a temperature sensor is immersed in the object to be heated in the pot, and temperature information obtained by this temperature sensor is used. a control circuit that controls the heating source based on the heat source, and the control circuit turns off the heating source when the temperature detected by the temperature sensor is equal to or lower than a predetermined value after a certain period of time has elapsed after the heating source was turned on. A heating cooker that features: