JPH0230151B2 - KANETSUCHORISOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heating cooking device such as an electric stove or a gas stove.

BACKGROUND ART Conventionally, when cooking tempura, the temperature of the oil has a large effect on the cooking result, and the temperature of the oil must be set at 180°C for good cooking.
For this reason, using a heating cooker such as an electric stove,
In order to cook tempura, the user had to rely on his or her experience and intuition, or manually adjust the heat using a thermometer or the like.

There are also deep-fried food cookers intended exclusively for use with tempura, and the output of the heating means can be turned on or off using a thermostat attached to the bottom or side of the oil container.
However, there were some that controlled the temperature according to the temperature set by the thermostat.

Problems to be Solved by the Invention With such conventional technology, it is possible to control the temperature of the oil to a set temperature of 180°C, but this is not possible unless the oil container is dedicated to the oil container, as in the above-mentioned deep-fried food cooker. When using an unspecified pot such as an electric stove or a gas stove, the thermal conductivity differs depending on the material of the pan, resulting in a difference in the temperature correlation between the oil temperature and the bottom of the pan. Therefore, when controlling the temperature by detecting the temperature at the bottom of the pot, even if the setting is kept constant, the temperature of the oil will vary depending on the pot being used, making it applicable to cooking devices such as electric stoves. It wasn't something. Also, even if applied,
The temperature controlled by the pot varied, making accurate temperature control impossible.

The present invention solves the above-mentioned problems, and aims to provide a heating cooking device having a temperature control function that can cook tempura while reducing variations in set temperature depending on the material of the pot. .

Means for Solving the Problems In order to solve the above conventional problems, the present invention has the following features:
A heating means for heating a pot or the like, a temperature detection means for detecting the temperature at the bottom of the pot, and a temperature setting means for manually inputting a temperature setting level from the outside and outputting a setting signal of the temperature to be controlled; heating control means for controlling the output of the heating means so that the temperature set by the temperature setting means and the temperature detected by the temperature detection means are equal; an initial temperature rise slope detection means for detecting the slope of the temperature rise; and a correction means for correcting the output of the temperature setting means in correlation with the slope of the initial temperature rise to adjust the control temperature; In other words, the material of the pot is detected from the delay in temperature rise, which correlates to thermal conductivity.
The temperature accuracy during control is improved by correcting the temperature difference that occurs due to the material of the pot, which is the main cause of the temperature difference between the set temperature, that is, the temperature detection means at the bottom of the pot, and the oil temperature. .

Effects According to the above configuration, after heating is started by the heating means, the material of the pot is determined based on the delay time of temperature rise mainly due to the thermal conductivity of the material of the pot, and the correction means sets the temperature input from the temperature setting means. By correcting the temperature, temperature errors caused by the pot can be reduced, thereby improving temperature accuracy.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. FIG. 1 shows a specific configuration of the present invention. In the figure, 1 is a pot into which oil or the like is put. 2 is a heater constituting a heating means for heating the pot 1; 3 is a heat-sensitive element; this heat-sensitive element 3 detects the temperature of the bottom back surface of the pot 1; its output is input to the temperature input means 4; These members constitute the temperature detection means. Reference numeral 5 denotes a variable resistor, and this variable resistor 5 is used to input a set temperature from the outside.The value is inputted to the setting input means 6 and becomes the set temperature, and these members constitute the temperature setting means. There is. Reference numeral 7 denotes an initial temperature rise slope detection means, which receives the temperature signal from the temperature input means 4 and detects the temperature rise slope of the bottom of the pot immediately after the start of heating.
Reference numeral 8 denotes a correction means, which inputs temperature rise delay information from the initial temperature rise slope detection means 7, performs calculations, adds a correction value to the setting value input from the setting input means 6, and outputs the result. do. 9 is a heating control means, and this heating control means 9 is connected to the temperature input means 4.
and the temperature set by the setting input means 6 corrected by the correction means 8, and controls the output of the heater 2 so that the comparison values become equal. It is. The initial temperature rise slope detection means 7 and the heating control means 9 are configured to start operating upon input from a start switch 10.

The heating cooking apparatus of the present invention configured as above will be described in detail below.

FIG. 2 is a diagram showing the correlation between time and oil temperature when oil temperature is controlled by changing various pots using a conventional temperature control method. This FIG. 2 will be explained below.

In the conventional control method, the central part of the bottom of the pot is used as a detection part, the temperature is detected by a sensor, etc., and the output is adjusted so that the detected temperature becomes the set temperature. With such a control method, the detected temperature is not the oil temperature in the pot, but the temperature at a distance equal to the thickness of the bottom of the pot. Therefore, even if the temperature of the detection part is controlled to the set temperature, the actual oil temperature is
As shown in Figure 2, the oil temperature will be different from the setting, for example, when using an aluminum pot and an iron pot, the oil temperature will be lower than the set temperature as shown at 11 and 12, and if a stainless steel pot with a large heat capacity is used. In this case, the oil temperature becomes higher than the set temperature as shown at 13. Further, the temperature difference between the set temperature and the oil temperature varies depending on the size and shape of the pot, the amount of oil, etc., but it is small compared to the influence of the material of the pot. In other words, the difference between the set temperature and the oil temperature has a correlation with the heat transfer at the bottom of the pot, and is almost determined by the material of the pot.The material of the pot is determined and the temperature is corrected according to the material. By adding , it is possible to increase the control accuracy of oil temperature.

Next, a method for determining the material of the pot will be explained based on FIG. 3. FIG. 3 is a diagram showing the correlation between the temperature at the center of the back surface of the pot and time in the initial state when heating is started from a state where the pot etc. is not heated, that is, from a state of room temperature. The horizontal axis of the graph indicates the passage of time, and heating by the heating means is started from t=0. The vertical axis indicates the temperature at the center of the bottom of the pot. As is clear from Fig. 3, immediately after heating starts, the back side of the pot bottom is heated from the part of the bottom closest to the heating means, and the temperature increase due to this heating is transmitted in the direction of the surface of the bottom of the pot, and then to the center of the back side of the bottom of the pot. Since the speed of transmission varies depending on the material of the pot, the temperature rise at the center also correlates with the material of the pot. In other words, if the material is made of a material with good heat conductivity, such as an aluminum pot, the temperature at the bottom of the pot will rise quickly, and if the material has poor heat conduction, such as a stainless steel pot, the temperature will rise slowly.The speed of this temperature rise can be detected. This allows the material of the pot to be detected.

That is, the heating cooking apparatus having the configuration shown in FIG. 1 operates according to the principle described above, and its operation will be explained below.

A user fills the pot 1 with oil or the like and places the pot 1 on the heater 2. Further, the cooking temperature is input through the variable resistor 5, the start switch 10 is turned on, and a start signal is given to the device to start the operation of the device. When the start switch 10 is turned on, the temperature at the center of the back surface of the pot bottom detected by the temperature sensing element 3 is provided to the heating control means 9 via the temperature input means 4. At this time, the temperature at the center of the bottom of the pot is
Almost room temperature. Further, the set temperature inputted by the variable resistor 5 is inputted to the correction means 8 via the setting input means 6. At this time, the correction means 8 is not given a correction signal and outputs the input set temperature to the heating control means 9. This heating control means 9 compares the temperature input from the temperature input means 4 and the temperature input from the correction means 8, but since the bottom back temperature of the pot from the temperature input means 4 is lower than the set temperature from the correction means 8, The control means 9 controls the heater 2 to the maximum output. At the same time, the initial temperature rise slope detection means 7 detects
A signal of the bottom back surface temperature of the pot is inputted from the temperature input means 4, and the differential value of the initial temperature rise is detected. The initial temperature rise slope detection means 7 outputs an output correlated to the slope of this temperature rise to the correction means 8. That is, if the pot 1 is made of aluminum or the like, a signal indicating a large inclination is output, and if the pot 1 is made of stainless steel, a signal indicating a small inclination is output. Based on this output signal, the correction means 8
The setting input is corrected and outputted to the heating control means 9. For example, if the pot 1 is made of aluminum or the like and the initial temperature rise slope detecting means 7 outputs a signal with a large slope, the correction means 8 adjusts the temperature corresponding to ΔT ₁ in FIG. 2 to the set temperature. If the pot 1 is made of stainless steel or the like and the initial temperature rise slope detection means 7 outputs a signal indicating that the slope is small, the temperature corresponding to ΔT ₃ in Fig. 2 is set. Adds correction by subtracting from the temperature and outputs the result. After the initial temperature rise slope detection means 7 outputs the detected temperature rise slope to the correction means 8, the correction means 8 outputs a temperature obtained by adding correction to the set temperature set by the variable resistor 5. become. Therefore, the heating control means 9 works to compare the corrected set temperature and the temperature detected by the temperature sensing element 3, and to control the output of the heater 2 so that the comparison matches, so that ultimately Temperature sensing element 3
The temperature of the oil in the pan 1 becomes stable at the corrected set temperature, and when the temperature of the temperature sensing element 3 becomes stable at the corrected set temperature, the temperature of the oil in the pot 1 is changed by the variable resistor 5. Almost equal to the set temperature. Furthermore, even if the material of the pot changes, the temperature of this oil is corrected by the comparison means 8 as explained above, so the temperature of the oil remains the same as the temperature set by the variable resistor 5. .

As described above, according to the configuration shown in FIG. 1, it is possible to construct a high-precision heating cooking device that can control the oil in the pot to a set temperature regardless of the type of pot, and Since the accuracy is high, the user can cook with peace of mind.

FIG. 4 shows a specific circuit diagram according to an embodiment of the present invention, in which 21 is an AC power source, 22 is a heater for heating a pot, etc., and 23 is a relay contact for controlling energization to the heater 22. So, relay coil 2
It is turned on and off by 4. 25 is a rectifier for inputting AC voltage and supplying DC voltage to each circuit. Reference numeral 26 denotes a thermistor, which is not shown in the figure, but is installed to detect the temperature at the center of the bottom back surface of the pot heated by the heater 22, and exhibits a negative resistance change depending on the temperature. 27 is a resistor connected in series with the thermistor 26 and divides the DC voltage; 28 is a variable resistor for externally inputting a set temperature; 29 is a resistor connected in series with the variable resistor 28 and divides the DC voltage; 30 is an A-D converter which inputs a voltage correlated to the temperature detected by the thermistor 26, which is divided by the thermistor 26 and the resistor 27, and outputs a digital signal correlated to this voltage. Further, 31 is an A-D converter, which inputs a voltage that is divided by a variable resistor 28 and a resistor 29 and that correlates to the set temperature that is input from the variable resistor 28, and outputs a digital signal that correlates to this input voltage. It is something to do. The resistor 32 and the switch 33 are connected in series between the DC power sources and are configured to convert an external switch operation into a voltage signal. Further, 34 is a transistor for switching the current flowing through the relay coil 24, 35 is a base resistor for limiting the base current of the transistor 34, and 36 is a transistor for switching the current flowing through the relay coil 24.
protection diodes, 37 are input terminals I ₁ , I ₂ , I ₃
an input section including an output terminal O1; an output section including an output terminal _O1 ;
a storage unit that stores various data and programs, and controls the input unit, output unit, and storage unit;
It is a microcomputer that has a calculation control section that performs various calculations, etc., and includes a thermistor 26 and a resistor 27.
and A-D converter 30 constitute temperature detection means and initial temperature rise slope detection means, and variable resistor 2
8, a resistor 29, and an A-D converter 31 constitute a temperature setting means, and a resistor 35 and a transistor 34 constitute a temperature setting means.
The relay coil 24, relay contact 23, and diode 36 constitute a heating control means, and the internal storage section and arithmetic control section constitute a correction means.

Figure 5 shows the difference between the set temperature and oil temperature shown in Figure 2,
It is a graph showing the correlation between ΔT in the figure and the experimentally measured value of the slope value of the temperature rise at the center of the lower surface of the pot bottom in FIG. 3, that is, the time T _S until the temperature rises by 2.5 degrees from the initial temperature.

FIG. 6 is a diagram showing the operation of the microcomputer 37 of FIG. 4.

The operation of the embodiment shown in FIG. 4 will be explained below using FIGS. 5 and 6.

The microcomputer 37 starts from step 41 in the flowchart, and first performs initial settings at step 42, in which case it clears each RAM. Next, in step 43, the voltage divided from the input terminal _I3 by the resistor 32 and the start signal switch 33, that is, if the switch 33 is turned on,
The GND voltage is input, and if it remains off, the VDD voltage is input, and the input signal is determined in step 44. If the result of this determination is the VDD voltage, it is determined that the switch 33 is not turned on, and steps 43 and 44 are repeated until it is turned on. When the switch 33 is turned on, the process moves to step 45 and the device begins to operate.
Steps 45 to 49 are for measuring the differential value of the initial temperature rise of the thermistor 26, that is, the time t _s required for the temperature to rise by 2.5 degrees from the initial temperature T ₀ in FIG. 3. In step 45, a signal obtained by digitally converting the voltage divided by the thermistor 26 and the resistor 27 by the A-D converter 30 is inputted from the input terminal _I1 as the detected temperature of the thermistor 26. The input temperature at this time is stored in the memory section of the microcomputer 37 as the initial temperature _T0 , and at the same time, in step 46, the temperature _Ts
Start a _ts timer that counts the time by the program of the microcomputer 37,
Output VDD voltage from output terminal O ₁ and connect heater 22
Start energizing. Output of output terminal _O1 is VDD
When the voltage reaches the transistor 3 through the resistor 35
4, current flows through the base of the transistor 34, causing conduction between the collector and emitter of the transistor 34, current flows through the relay coil 24, and the relay contact 23 closes, which causes current to flow through the heater 22 and heat the pot. Further, if the output of the output terminal O ₁ is at the GND voltage, the base current of the transistor 34 does not flow, so the relay contact 23 is turned off, and therefore no current flows to the heater 22 . Next, in step 47, the temperature detected by the thermistor 26 is input as the temperature T _S from the input terminal _I1 in the same manner as above, and in step 48,
Input temperature T _S and above initial temperature T ₀ +2.5deg
The temperature of T _S is compared with the temperature of T ₀ +
Repeat steps 47-48 until it is equal to or greater than 2.5deg. During this time, the count increases as the _ts timer time passes.
has been done. The temperature of the pot and the oil in the pot rises due to heating by the heater 22, and the temperature detected by the thermistor 26 increases.
When T _s becomes higher than or equal to T ₀ +2.5deg, the process proceeds to step 49 and the operation of the t _s timer is stopped. The timer value at this time becomes _ts . Although not shown, the _ts timer configured by a program is accurate because it counts based on the command cycles of the microcomputer 37 that operates based on the oscillation of the ceramic oscillator.

In step 50, a signal obtained by digitally converting the voltage divided by the variable resistor 28 and the resistor 29 by the A-D converter 31 is inputted as the set temperature _TSET of the variable resistor 28 from the input terminal _I2 , and in step 51 Then, calculate the initial temperature rise differential value t _s time and the set temperature T _SET . This calculation is performed by approximation based on the regression _line from the experimental data shown _in FIG.
The correction value is (T _SET −T _pil )=180−(0.45×t _s +
162), the correction calculation formula is set temperature T _HO = after correction.
T _SET +18−4.5×t _s . i.e. step 51
In this step, T _HO = T _SET −27 + 0.9×t _s is calculated from the rise time t _s input in steps 45 to 49 and the T _SET data input in step 50, and the corrected Find the set temperature T _HO . step 52
Then, in the same way as above, the temperature of the thermistor 26 is input as the current temperature T _o , and in step 53, the current temperature T _{o is} input.
and the corrected set temperature T _HO , and if the current temperature T ₀ is low, the output from the output terminal O ₁ is changed in step 54.
The heater 22 is energized to VDD voltage to heat the pot. Further, if the current temperature T _o becomes equal to or higher than the corrected set temperature T _HO , the output of the output terminal O ₁ is set to the GND voltage in step 55, and the power to the heater 22 is cut off to stop heating the pot. . By repeating steps 52 to 55, the temperature of the thermistor 26 becomes equal to the corrected set temperature T _HO and is stably controlled. As a result, the temperature of the oil approximately reaches the set temperature T _SET set by the variable resistor 28 from the outside. For example, when using an aluminum pot with a 2mm thick bottom, the oil temperature would be 168℃ even if the temperature setting was 180℃.
However, according to the cooking device of this embodiment, the rise time t _s is 12 seconds, the corrected set temperature is 192.6°C, and the bottom bottom temperature of the pot is controlled at 12.6 degrees higher than the set temperature. Therefore, the oil temperature is approx.
The temperature becomes 180.6℃, which is almost equal to the set temperature. The same applies to other types of pots. Note that in the flowchart of FIG. 6, not only steps 52 to 55 are repeated, but steps 50 to 51 and steps
By repeating steps 56 and 57 at the same time,
In steps 50 to 51, if the user changes the variable resistance 28 for inputting the set temperature midway through, and in steps 56 to 57, if the user turns off the switch 33 to stop the device, step 58 This is to ensure that the equipment can be stopped at any time.

As described above, according to the embodiment shown in FIG. 4, it is possible to construct a high-performance cooking apparatus that can control the temperature of oil to be equal to the set temperature. Furthermore, this allows the user to easily cook tempura or the like.

In the embodiment shown in FIG. 4, the initial temperature rise differentiating means is a means for detecting the time _ts from the start of heating until the temperature rises by 2.5 degrees, but this is not limiting. As shown in a diagram similar to Figure 3 in Figure 7, there is also a correlation with the temperature rise ΔT _S after a predetermined period of time after the start of heating, and it is possible to identify the pot. It goes without saying that the same effect can be obtained by finding the differential value of the temperature rise. Further, the heater of the heating means is the same for a stove and a high-frequency heating device that use gas or the like as fuel.

Effects of the Invention As described above, according to the present invention, the temperature of the ingredients in the pot can be controlled to a set temperature in a stable state and with high precision, regardless of the material of the pot, with an extremely simple circuit configuration, and it can be put into practical use. This provides an extremely useful cooking device.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of the heating cooking device according to the present invention, Fig. 2 is a correlation diagram of oil temperature and time in a conventional heating cooking device, and Fig. 3 is a diagram showing the relationship between time and the lower surface of the bottom of the pot in the initial stage of heating. Correlation diagram with temperature, 4th
The figure is a specific circuit diagram of an embodiment of the heating cooking device according to the present invention, Figure 5 is a correlation diagram between the difference between the set temperature and oil temperature and the temperature rise time at startup, and Figure 6 is the microcomputer shown in Figure 4. FIG. 7 is a flowchart showing the operation of FIG. 7, which is a correlation diagram similar to that of FIG. 3 but with a different correlation. 1... Pot, 2... Heater, 3... Temperature sensing element, 4
... Temperature input means, 5 ... Variable resistance, 6 ... Setting input means, 7 ... Initial temperature rise slope detection means, 8
. . . correction means, 9 . . . heating control means.

Claims (1)

[Claims] 1. A heating means for heating a pot, etc., a temperature detection means for detecting the temperature at the bottom of the pot, and a temperature setting signal for manually inputting a temperature setting level from the outside and controlling the temperature. a temperature setting means for outputting, a heating control means for controlling the output of the heating means so that the temperature set by the temperature setting means and the temperature detected by the temperature detection means are equal, and the temperature detection after heating is started. an initial temperature rise slope detection means for detecting the slope of temperature rise of the temperature detected by the means; and a correction means for correcting the output of the temperature setting means in correlation with the slope of the initial temperature rise to adjust the control temperature. A heating cooking device equipped with 2. The initial temperature increase slope detection means includes an initial value storage means for temporarily storing the temperature detected by the temperature detection means before or at the time of starting heating of the pot, etc. by the heating means, and this initial value storage means. temperature comparison means for comparing a temperature obtained by adding a preset temperature to the temperature stored by the temperature detection means and the temperature detected by the temperature detection means, and outputting a signal when the temperature detected by the temperature detection means is higher; A patent claim consisting of a timekeeping means that starts timekeeping upon the start of heating and stops timekeeping in response to a signal from the temperature comparison means, and a calculation means that performs an operation on the timekeeping result of the timekeeping means and outputs the result to the correction means. The heating cooking device according to item 1.