JPS61265426A - Automatic microwave oven - Google Patents

Abstract

PURPOSE:To make variation small in finishing by installing such a control part that heats sequentially foodstuff by a weight sensor and a cooking sensor and calculates an added re-heating hours after total operating hours of microwave are counted during thawing and heating operation. CONSTITUTION:When a key 4 commanding thawing and cooking is operated, a control part 5 which controls power feeding to a microwave generating means 9 by a certain microwave output on the basis of the weight of foodstuff detected by a weight sensor 10. Successively, said microwave output is increased and required time T2 until the foodstuff under heating is brought into a specified heating condition by a cooking sensor 12 is counted and to a value K1T1 obtained by multiplying a constant K1 by required time T1 for said defrosting, T2 is added and then K2(K1T1+T2) obtained by multiplying said value K1T1+T2 by a constant K2 is designated as an added heating time controlled by the control part. Thereby, an automatic microwave heating device which realizes thawing and cooking sequence with small variation in finishing is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to high-frequency heating devices such as microwave ovens.
The present invention relates to an automatic high-frequency heating device that can be used to defrost and cook frozen foods.

BACKGROUND OF THE INVENTION In general, defrosting of frozen foods by microwave heating is completed in an extremely short time, resulting in good quality after defrosting, and has been put to practical use more widely than ever before. Here, we will refer to the so-called thawing cooking method, which involves heating frozen cooked foods and mixed vegetables as they are after thawing to raise the temperature of the food.

Conventionally, such defrosting cooking methods generally involve heating with a constant high-frequency output from defrosting to cooking. Then, using a cooking sensor such as a humidity sensor or a gas sensor, it detects when the heating of the food is completed and automatically ends the cooking. This thawing cooking method requires a short heating time, but on the other hand, cold spots tend to appear in the center of the food, and homogeneity is impaired between areas that start melting early and areas that melt slowly, resulting in uncooked food. There were problems with the finish.

In order to improve the above-mentioned problems, a configuration has been proposed in which thawing and cooking are automatically performed sequentially (%Gan Sho 59-1j4970). This system controls the first half of defrosting using a weight sensor and the second half of cooking using a gas sensor, and divides defrosting into four small modes to improve the quality of defrosting.

Problems to be Solved by the Invention However, in this thawing cooking method, the thawing in the first half of heating is controlled by a weight sensor, so there is a lot of variation in food temperature at the end of thawing, making it difficult to cook in the second half. Even with value control (additional heat control), there is a problem that the finish becomes uneven.

This point will be explained in detail.

FIG. 6 shows the thawing cooking sequence described in Japanese Patent Application No. 14970/1983. FIG. 6(a) shows the microwave heating pattern, FIG. 6(b) shows the temperature rise in each part of the food, and FIG. 6(c) shows the change in absolute humidity inside the heating chamber.

The thawing cycle consists of four small modes T1 to T4, T
is full power, T is rest, and T3 is medium power.

T4 is operated at low output and controlled so that the temperature of each part of the food changes as shown in Figure (b). That is, the frozen food passes through the zone of maximum ice crystal formation within a short period of time, and microwaves are applied intermittently to prevent boiling or the like from occurring on the surface, and thawing is performed using the repeated heating.

Next, in the cooking cycle, the power is returned to full power and the food is heated until the cooking sensor reaches a predetermined heating state, for example, until it is confirmed that the absolute humidity in the heating chamber has changed by a predetermined change Δh.

Assuming that this humidity detection point is P, the additional heating time is calculated as KT5 (K: constant) based on the heating time T6 up to point P in the cooking cycle. In other words, the total heating time is T. -11+K) becomes T6. This is a value control (additional heat control) that is commonly used in automatic cooking using sensors.
This is the method.

By the way, the T1 to T4 times of the thawing cycle are calculated based on the weight of the food. For example, if the weight of food is W, then T1 = 1W and T2 = 2W.

T3: is calculated as 3W, 'r4=x4w. This is because the dielectric loss of frozen food is constant regardless of the material. In other words, if meat or vegetables are frozen, the thawing time can be determined solely by their weight. Therefore, if the weight of the food can be accurately detected and the temperatures of the frozen food are evenly matched, the food can be defrosted effectively.

However, in order to accurately detect the weight of food, it is generally necessary to perform a "tare" process in which the weight of the container is subtracted, which is extremely troublesome in operation. The temperature of frozen foods also varies greatly depending on the capacity of the freezer and whether the food is immediately taken out of the freezer or left out for a while.

For the former, the total weight of the food and container W0 and the food weight W
The method of estimating the food weight from the correlation with Figure 5 shows this correlation, where each point represents the total weight W of various frozen foods placed in various containers. The relationship between food weight W and food weight W is shown. It can be seen that there is a correlation between the two: W=o, ss'W0. Therefore, the thawing time in each mode mentioned above can be calculated without the troublesome process of subtracting the weight of the container.
It can be calculated from the total weight W0. For example, T1== K1w=
K Xo, 35W0 = 1'W0 (K, ': constant).

Although this method is very good in terms of operation, the error increases as the data deviates from this correlation straight line, and there are cases where over-decompression occurs and conversely, under-decompression occurs.

On the other hand, in the case of the latter, well-frozen foods usually exhibit a temperature of around -2°C, but the temperature rises rapidly as soon as the food is taken out of the freezer. -For example, when frozen croquettes were left indoors for 16 days, the food temperature rose from -20°C to -10'C. This shows that there is a considerable difference in temperature at the end of the thawing cycle between food purchased at the supermarket and cooked immediately after returning home, and food left in the freezer for several days or more.

Therefore, the detection time T5 from the start of the cooking cycle to the humidity detection will vary greatly due to the above two factors. If it is over-thawed, T5 will be shorter, and if it is not thawed, it will be longer. If you multiply this unstable T6 by the value and heat it additionally,
There has been a large variation in the finish.

The present invention solves these conventional problems and provides an automatic high-frequency heating device that realizes a thawing cooking sequence with little variation in finished product.

Means to Solve the Problems The automatic high-frequency heating device of the present invention is equipped with a weight sensor and a cooking sensor, and the control section uses both sensors to sequentially heat the object to be heated, and the control section also controls the heating process during thawing and heating. The total operating time of the microwave is counted and the additional heating time is calculated based on this.

Function: The automatic high-frequency heating device of the present invention counts or calculates only the microwave operation time out of the thawing time calculated according to the weight of the object to be heated, and adds the detection time during the cooking cycle to this. Multiply by the value to determine the additional heat time. This allows thawing and cooking to be carried out without being affected by the weight of the food or the starting temperature of the food.

EXAMPLE Hereinafter, an automatic high-frequency heating apparatus according to an example of the present invention will be explained with reference to the drawings.

As shown in FIG. 2, the automatic high-frequency heating device according to the present invention includes a main body 1 containing a heating chamber, a door body 2 that freely opens and closes the opening of the heating chamber, and an operation panel 3 that inputs various commands. It is formed by A thawing/cooking key 4 is arranged on the operation panel 3 for instructing thawing/cooking of frozen food.

FIG. 3 is a block diagram showing one embodiment of such an automatic high-frequency heating device. Commands input from the thawing/cooking key 4 on the operation panel 3 are decoded by the control unit 6. Then, the control unit 6 starts defrosting and cooking the frozen food, which is the object to be heated 7 placed in the heating chamber e. The heating is controlled by being supplied with power via a driver 8 to a magnetron serving as high frequency generating means 9.

The weight sensor 10 detects the weight of the object to be heated 70 on the mounting plate 11. Further, the cooking sensor 12 is realized by a humidity sensor, a gas sensor, or the like, and reacts to steam or gas discharged by the fan 13 to detect when cooking is completed. Reference numeral 14 represents an exhaust guide, and reference numeral 16 represents a motor that rotates the mounting plate 11 to improve uneven heating.

Note that the weight sensor 1o may employ a capacitance method or a strain gauge method to detect the amount of displacement of the mounting plate 11, or a vibration method to measure the natural frequency.

In addition, as the cooking sensor 12, Matsushita Electric's relative humidity sensor "Humiceram", also an absolute humidity sensor? You can use products such as ``Neo Humicerum'' and Figaro's Gascenti #813.

FIG. 1 shows a heating putter for thawing and cooking showing an embodiment of the present invention. Figure 81 (,) shows the state of the microwave output, Figure 1 (the phrase represents the temperature rise in each part of the food being heated, and Figure 1 (C) represents the amount of steam generated from the food being heated.

Heating consists of three modes. First, in T1, the microwave is heated at full power, and the time is calculated by 71=1W0 (K1: constant) based on the detected total weight W0. In Jin's T1 mode, frozen foods are heated all at once.
The surface is heated until it partially reaches 40-60°C. As shown in Figure 1(b), at the end of the T1 mode, the surface temperature is partially raised to 40 to 60"C to a state where local "boiling" occurs, so to speak, and the next T2 mode is heated.
You can enhance the standing effect in mode. At this time, the internal temperature of the food is still 12 to 3°C, and in this state, the mode shifts to T2 mode.

In T2 mode, the microwave power is reduced to around 180 watts and carryover heating is performed.

Similar to T1, T2 time is calculated using T2= and 2W0 (K2: constant). In T2 mode, the temperature difference between the surface and the inside is large, so the temperature moves quickly, and the frozen part inside is completely thawed at the end of T2 mode. T2
The power in the mode may be a simple pause, but it is better to use a low output of about 90 to 260 watts as in this example.
Total heating time can be shortened. With this level of output, there is not enough energy to advance the boiling process, but it is effective in defrosting the inside (see Figure 1(b)).

In this embodiment, the thawing cycle is simplified into two modes, T1 and T2, but it is of course possible to use four modes as in the conventional example shown in FIG.

Now, once the food is defrosted in this way, the next step is to proceed to the cooking cycle using the cooking sensor. Here, cooking sensors such as humidity sensors and gas sensors are used to control the amount of steam Δ from the food.
The time T3 up to the time point P when h is detected is counted. Then, when the point P is reached, additional time is calculated. The additional time T4 is determined by the following formula.

T4=1 (T, +2T2+T3) Here, and 2 are constants. K1 is a cooking constant, and a value such as 0.2 is selected depending on the food. K2 is a power coefficient, depending on the average power in T2 mode, for example full power is 600 watts,
If the T2 mode is 180 watts, a ratio of 0.3 between the two is selected. Finally, 2T2 calculates the on-time of intermittent microwaves.

From the above, according to the above formula, the total on-time of the microwave including the thawing cycle is multiplied by the K value, and the cooking time T3 is determined by the influence of the weight and starting temperature of the food.
Even if the temperature fluctuates, stable additional heat can be applied.

Next, the control program of the microcomputer, which is the control section, will be explained using the flowchart shown in FIG. FIG. 4 is a flowchart showing the thawing cooking sequence. First, the thawing cooking key input is decoded and the result is 4A.

The weight W0 of the food is measured 4B0 Next, based on this, T, time and T2 time are calculated 4C0 Then various 7 lags and lags are reset, and color/color is initialized 4D0 Next, the start key is input. 4E when deciphered.

The microwave is turned on in 4F, the T1 flag is set, 4G0 clock is counted sequentially, and when one second has passed, 4H, the T1 flag is checked, and the T1 time is decremented after 4N.

Then, it is checked whether the T1 time has been counted up or not, and the T1 time reduction process is continued until the count has been counted up.

When the T1 time has elapsed, the T1 flag is set to 4L, the T2 flag is set, and the mode shifts to 4M and T2 mode.

T2 flag check 4N enters the T2 mode processing routine. First, in order to control the microwave intermittently, Q
The count in the N10FF register and the ON/OFF control of the relay are performed according to the contents 40, then the T time is reduced 4P, and it is checked 4Q whether or not the T2 time has been counted up.

When the T time has elapsed, the T2 flag is raised to 4.
H. The microwave is turned on again for 4S, the intermittent output ends and full power is reached. Then, it shifts to T3 mode.

In T3 mode, the HUM flag is first checked 4T, and since this is not set initially, the T3 time is counted up 4U0, and the cooking sensor checks whether a change in humidity exceeding a certain threshold value Δh has been detected. 4V, T3 time counting continues until a humidity change is detected.

When a humidity change of Δh or more is detected, the HUM7 lag is set to 4W, and the additional heat time T4 is calculated according to the following formula: 4X0 T4 = 1 (T1 + 2T2 + T3) K2 is on during T2 time It has already been mentioned that the time is selected so that the cumulative value of the time can be calculated. However, when the microwave is intermittent, the effective output value changes depending on the length of the on-time and the length of one intermittent cycle, so 2 may be selected according to this effective output value. For example, it is also possible to select 2 as 0.

At this time, the additional heating time is calculated based on the sum of the full power temporary times T1 and T3, which are effective for heating.

When the HUM7 lag is set, additional heat control is performed and the T4 time is reduced. 4Y0 When the T4 time counts up, 42. The power is turned off and 4a,
Cooking ends 4b0 Effects of the Invention As described above, the automatic high-frequency heating device of the present invention is equipped with a weight sensor and a cooking sensor, and first defrosts food at a high output based on the weight of the food, and then defrosts the same at a low output. The heating is carried over based on the weight, and then the cooking sensor uses high output again to detect the point at which the food reaches the predetermined heating state, calculates or counts the total on-time of the microwave, including defrosting, and The structure is such that the food is multiplied by a value to generate additional heat, allowing thawing cooking with small temperature differences without localized boiling or low-temperature areas in the center. Furthermore, even if the sensor detection time during the cooking cycle varies due to the weight or the starting part of the food, stable additional heat can be applied.

[Brief explanation of drawings]

Fig. 1 is a time chart showing a heating pattern of an automatic high-frequency heating device according to 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 configuration, and Fig. 4 is a control section. Microcomputer control 70-chart, FIG. 5 is a graph showing the relationship between the total weight and the weight of item X, and FIG. 6 is a time chart showing the heating pattern of conventional thawing cooking. 4... Thawing cooking key, 6... Control unit,
6... Heating chamber, 7... Heated object, 9.
... High frequency generation means, 10 ... Weight sensor,
12...Cooking sensor. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure E-1, 2-J flea 34 3--Ichij'P Bakir Figure 4 Figure 5 O is 5 11 ■ Ri (7) Figure 6

Claims (1)

[Claims] A heating chamber in which an object to be heated is placed, a high-frequency generating means coupled to the heating chamber, a control section controlling power supply to the high-frequency generating means, a weight sensor detecting the weight of the object to be heated, and a high-frequency generating means coupled to the heating chamber; The control unit includes a cooking sensor that detects the heating state of the heated object, and a key that commands thawing and cooking of frozen food, and when the key is operated, the control unit detects the weight of the heated object detected using the weight sensor. Based on this, defrosting is performed using a certain high-frequency output, then the high-frequency output is increased, and the time T_2 until the heated object reaches a predetermined heating state is counted using the cooking sensor, and the time required for the defrosting is calculated using the cooking sensor. Multiply T_1 by a constant K_1 and take the sum of K_1 and T_1,
The time K_2 (K_1T_1+
An automatic high-frequency heating device configured to control T_2) as an additional heating time.