JPH0640518B2 - Automatic heating device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for optimally heating an object to be heated in an automatic heating device such as an automatic microwave oven equipped with a sensor and capable of automatic cooking.

2. Description of the Related Art The automatic heating device described in Japanese Patent Application No. 60-122977 is
Using a sensor, the time change of the steam generated from the object to be heated is detected, the cooking variable K corresponding to this is calculated, and at the time T ₁ required until a predetermined amount of steam is detected from the object to be heated,
It is also configured to multiply the cooking variable K to calculate the additional heating time KT ₁ .

FIG. 8 is a time chart showing this conventional example. This automatic heating device is provided with a sensor for detecting steam and various gases generated from an object to be heated, and a control unit has two counter means and an arithmetic means. The controller counts the detection time T ₁ until the detection value of the sensor reaches a certain detection threshold value α by the first counter means, and the detection value of the sensor by the second counter means changes the humidity threshold value h. The rise time t from when the detection value reaches the detection threshold value α to the detection threshold value α is counted. Then, the ratio t / T ₁ is calculated, the cooking variable K is determined according to the value, and
₁ multiplied by the chase determine the heating time KT ₁ (or arithmetic unit).

After the detection signal T _{1 has} elapsed, the control unit continues heating for the additional heating time KT ₁ .

With the above configuration, it is possible to judge the warming condition of the object to be heated by the t / T ₁ value and select the optimum K value. The optimum heating can now be performed regardless of the presence or absence of a cover or the difference in quantity.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, such a conventional automatic heating method is extremely effective when cooking food that has once been cooked, such as reheating, but it is very effective in preparing vegetables and preparing chicken liquor. When cooking raw materials such as steaming or thawing cooked frozen foods, it was not possible to heat well. The reason for this is that when extreme uneven heating of food is unlikely to occur, for example, reheating or the like, there is a strong correlation between how steam comes out and how warm the food is.
It is not possible that a part that has reached ℃ and a part that is completely unheated coexist. Therefore, the steam output is t /
It was effective to judge by the T ₁ value, estimate the warming condition of the food from this, and adjust the additional heating time. However, when cooking raw ingredients or when thawing, the food tends to be unevenly heated and the cooking time is long, so there is a mixture of boiled parts over 90 ° C and completely unheated raw parts and ice parts. That is not unusual. Especially in a microwave oven that heats an object to be heated by microwaves, a standing wave is generated in the heating chamber, and such heating unevenness is unavoidable.
For this reason, the correlation between how steam comes out and the degree of warming of food collapses, making it difficult to determine the additional heating time from the t / T ₁ value.

The present invention is to solve such a conventional problem, not only reheating, but also prepared vegetables, such as defrosting cooked frozen foods, such as defrosting cooked foods easily heated unevenly, heated various foods with one key The present invention provides an automatic heating device configured so that optimum additional heating can be performed regardless of the difference in the quantity.

Means for Solving Problems The automatic heating device of the present invention includes a sensor for detecting vapor and various gases generated from an object to be heated, and the control unit has a counter unit, a monitor unit, and a calculation unit. The control unit is provided with a heating unit whose power supply is controlled.

Operation The automatic heating device of the present invention counts the time T ₁ until the detection value of the sensor reaches a certain detection threshold value by the counter means, and monitors the speed of change of the detection value of the sensor by the monitor means. The cooking variable K is determined accordingly, and this and T ₁
Further heating is performed by KT ₁ multiplied by and the output of the heating means is switched to a low value from the steam generation point to ensure the determination of the monitoring means.

Example Hereinafter, an automatic heating apparatus according to an example of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the automatic heating device according to the present invention includes a main body 1 having a heating chamber built therein, a door body 2 for opening and closing the opening of the heating chamber, and an operation panel 3 for inputting various commands. ,
It consists of a cooking key 4 arranged on this.

FIG. 3 is a block diagram showing an embodiment of such an automatic heating device. The command input from the cooking key 4 on the operation panel 3 is decoded by the control unit 5. And the control unit 5
Starts heating the wave heating object 7 placed in the heating chamber 6. The heating is performed by supplying power to the magnetron, which is the heating means 9, through the driver 8.

The sensor 10 is realized by a humidity sensor, a gas sensor, or the like, and reacts with steam or gas discharged from the fan 11 to detect the time when cooking is completed. Reference numeral 12 is an exhaust guide, and 13 is a detection circuit.

The mounting tray 14 is rotationally driven by the motor 15, and uneven heating of the object 7 to be heated can be improved.

Examples of the sensor 10 include a relative humidity sensor and an absolute humidity sensor manufactured by Matsushita Electric, and a gas sensor # 813 manufactured by Figaro.
You can use an absolute humidity sensor made by Shibaura Electronics.

FIG. 1 is an embodiment showing the control sequence of the present invention. The amount of steam generated from the object to be heated 7 changes as shown in Fig. 1 (a). On the other hand, the microwave output is
It is controlled as shown in (b). That is, the time point H ₁ when the detected value of the sensor changes by the humidity change threshold value h is the steam generation point, and the time point H ₂ when the detected value of the sensor reaches a certain detection threshold value α is the steam detection point. The time T ₁ required until the time point H ₂ is counted as the detection time. Further, the microwave output is switched from the first output P ₁ to the second output P ₂ at time H ₁ . Here, P ₁ > P ₂ . In the example of FIG. 1, the microwave output is switched on and off,
All outputs are selected for P ₁ . And from H ₁ point to H ₂
The change in steam up to the time point is monitored by the monitoring means. In the example of FIG. 1, the monitor means is composed of a counter for counting the rising time t at the time points H _{1 to} H ₂ and an arithmetic means for calculating the ratio t / T ₁ between the rising time t and the detection time T _1. It is configured, and the cooking variable K is determined according to the value.

This processing is similar to that of the conventional example, but the point of the present invention is that the microwave output is switched at the time point H ₁ and the second output P ₂ is made smaller than the first output P ₁ . In other words, the H ₁ time point is the time point when at least a part of the food reaches 70 ° C. and steam begins to vigorously appear. For foods that are likely to cause uneven heating such as defrosting cooked frozen foods and preparing vegetables It is the time when the temperature difference with the still low temperature part becomes extremely large. Therefore, if the microwave output is switched to a low output at the time point of H ₁ , the temperature of the high temperature portion moves to the low temperature portion due to such temperature imbalance, and the uneven heating during the pause cycle of the intermittent operation can be improved. Be peeled off.

In addition, until H ₁ point, since it is heated at a high output all at once, it is natural that cooking is completed in a much shorter time than when it is heated at a low output from the beginning, but by intentionally making temperature unevenness inside the food like this , Heating at the subsequent second output P ₂ is effectively performed. This utilizes the fact that the temperature of food placed on a site where the electric field is weak does not rise easily over time, but the temperature rises relatively quickly due to heat conduction. That is, due to the temperature imbalance caused by the uneven heating, the temperature of the portion where the electric field is weak is raised by heat conduction. Therefore, compared to heating with low output from the beginning, heating can be performed in a much shorter time compared to the on time of the microwave, which is energy saving and economical.

The stationary heating after the time point of H ₂ is performed only for KT ₁ obtained by multiplying the cooking variable K by the detection time T ₁ . The third output P _{3 at} this time is
Since the heating unevenness has already been improved and the determination by the monitor means has been completed, it can generally be made larger than the second output P ₂ . Of course, P ₂ = P ₃ depending on the object to be heated,
Naturally, a configuration in which all outputs are used is conceivable.

By the way, the following table is a part of the data of frozen cooking of prepared frozen foods, which was carried out by using Matsuo Denki's whole body humidity sensor "Neohumyceram" and using Matsushita Denki's electronic orange. The condition was such that the food was wrapped in a wrap with a container, and the microwave output was P ₁ = 600 watts and P ₂ = P ₃ = 420 watts (10 seconds on, 14 seconds off).

When this table is plotted, as shown in FIG. 4, t / T ₁
It can be seen that there is a strong correlation between the value and the optimum K value. However, in the conventional method (the method disclosed in Japanese Patent Application No. 60-122977), reheating can be satisfactorily performed, but cooking such as thawing cooking in which heating unevenness is likely to occur is very small.
The optimum K value differs greatly due to the difference in / T ₁ value, which is extremely dangerous in practical use. However, in the method according to the present invention, t /
As shown in the figure, the relationship between the T ₁ value and the optimum K value was extremely gentle, yet a strong correlation was obtained. Therefore, K value and t /
There is a relationship of K = A (t / T ₁ ) + B (A, B: constant) with the T ₁ value, and in this example, A = 0.69, B = −0.
It will be 05. Also, since the K value cannot be negative, And can be approximated by a broken line of two straight lines.

Returning to FIG. 1 again, if the cooking variable K is treated as the function K (/ tT ₁ ) of t / T ₁ as described above, the total heating time T _o is T _o = T ₁ + K (t / T ₁ ) ・ T ₁ .

According to such a control sequence, even for foods such as thawed foods that are likely to have uneven heating, it is possible to properly and automatically select the optimum K value, which varies as shown in the above table, by the value t / T ₁ . That is, it is possible to combine the cooking keys, which conventionally had to be subdivided for each type of food, into one.

Next, a flow chart which is an embodiment of the control program when this control unit is composed of a microcomputer is shown in FIG.

First, the initialization program RUNs and the RAM is cleared and the output port is reset (A). Next, the clock is counted and basic data of various counters is created (B). In the case of a counter with a built-in counter, this is executed by hardware. Subsequently, the display data is output to perform a predetermined display on the display unit (C). Since dynamic lighting is generally used, display data is created for this purpose. Then, it is checked whether the heating device is in operation (D), and when it is not in operation, the key input is taken in and decoded (E). The operations of the cooking key and the start key are decoded and processed here.

If it is confirmed during operation during the operation check (D), it is first determined whether or not the humidity is detected before (F). The T ₁ time is counted until the humidity is detected, and the KT ₁ time (additional heat time) is counted down after the humidity is detected.

Explaining the control before humidity detection, it is first checked whether the humidity change ΔH exceeds a humidity change threshold value h.

ΔHh (G) Then, when this condition is satisfied, counting of the rising time t starts (H). At the same time, the microwave output is intermittently controlled
(I). The detection time T ₁ is counted regardless of the condition of the G term (J).

Next, it is checked whether the humidity change ΔH exceeds the detection threshold value α.

ΔHα (K) Until this is satisfied, the above T ₁ time counting routine is repeated, and when this is satisfied, t / T ₁ is calculated, and based on this, K (t / T ₁ ) and KT ₁ are calculated one after another. Be done (L). Then, the humidity detection processing ends, and the control shifts to additional heating control.

In the additional heating control, the microwave output is controlled intermittently first.
(M), then the additional heat time KT ₁ is counted down
(P), it is executed by supplying power (Q) until the content becomes zero. The additional heat time may be counted up and compared with the KT ₁ time calculated in the K term, and if they match, it may be determined that the heating has ended.

When the KT ₁ time ends, an end process such as notification by a buzzer is performed (R), and the process returns to START.

Next, another embodiment of the present invention will be described.

FIG. 6 is a chart showing a heating control method according to the embodiment of FIG. 7 in which a weight sensor 16 is added to the configuration of FIG. The difference from the above-described embodiment is that the H ₁ time point at which the microwave output is switched is calculated based on the weight of the object to be heated 7 detected by the weight sensor 16 regardless of the change in the amount of generated steam. It is a point. That is, the rough heating time T ₂ from the start of cooking to switching the output is calculated as a function of the weight W, and is calculated by, for example, T ₂ = CW + D (C, D: constant).

The effect of this embodiment is that the steam generation point is estimated from the weight, so that it is not affected by the wrapping method of the food. In other words, the steam generation point wraps the wrap firmly and firmly,
Although it fluctuates considerably depending on the relaxation, this method can always reduce the output from a certain point in time and stabilize the t / T ₁ value. The monitor means is not limited to the t / T ₁ value, and a differential value of t, an integrated value of generated steam, or the like can be used.

EFFECTS OF THE INVENTION As described above, the automatic heating device of the present invention includes the sensor for detecting steam or gas, the counter means measures the T ₁ time, and the monitor means measures the time change of the detected value of the sensor. Cooked variable K is determined and additional heating time K
The configuration is such that T ₁ is calculated and the output of the heating means is switched to a low value from the steam generation point, and the following effects can be obtained.

(1) When the optimum K value and t / T ₁ are linearly approximated by reducing the output at the steam generation point, the linear approximation formula has a gradual slope and a strong correlation is obtained.
_{Even if 1} slightly fluctuates, a stable optimum K value can be calculated and selected.

(2) It can be used for preparing vegetables that are prone to uneven heating, and for defrosting cooked foods.The automatic cooking, which had to be divided into multiple cooking keys in the past, has been combined into one key, and various foods and amounts differ. The optimum K value can be automatically selected regardless of the above.

(3) Due to the stepwise control of the output, the part that is hard to heat is effectively heated by thermoelectricity, and the heating is completed in a short time and with a small amount of electric power.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a heating control method of an automatic heating device in an embodiment of the present invention, FIG. 2 is a perspective view of the main body, FIG. 3 is a block diagram showing the same structure, and FIG. 4 is t / T. Explanatory drawing of one experimental data showing the relationship between ₁ value and optimum K value, FIG. 5 is a control flowchart of a microcomputer as a control unit, FIG. 6 is a block diagram showing another embodiment, and FIG. FIG. 8 is an explanatory diagram showing a control method, and FIG. 8 is an explanatory diagram showing a conventional heating control method. 4 ... Cooking key, 5 ... Control part, 6 ... Heating room, 7 ...
Object to be heated, 9 ... Heating means, 10 ... Sensor, J ... Counter means, H ... Monitor means, L ... Calculation means.

Claims (1)

[Claims] 1. A heating chamber in which an object to be heated is placed, a heating means coupled to the heating chamber, a control unit for controlling power supply to the heating means, steam generated from the object to be heated, and various types of steam. The control unit includes a sensor for detecting gas, and the control unit sets a steam generation point at a time point when a value detected by the sensor slightly changes, and sets the output of the heating unit to a second output lower than the first output. , And then counts the first counting time from the start of heating and the second counting time from the steam generating point by the counter means until a certain threshold value larger than the steam generating point is reached, and the first counting time by the monitoring means. And the second counting time are compared to judge the time change of steam generation, the calculating means calculates a continuous variable according to the output of the monitoring means, and the first count counted by the counter means. Multiplying the while, after the first counting time, the automatic heating apparatus configured to only follow heating the calculated product time.