JPH037813A - Cooker - Google Patents

Abstract

PURPOSE:To properly inform an abnormal state during food temperature detection by a method wherein an abnormal temperature change rate is determined according to the weight of food that is input from a food weight input element, and the abnormal state is informed when it is judged that the change rate of the temperatures detected by a food temperature detector is at the level of the abnormal temperature change rate. CONSTITUTION:An abnormal temperature change rate is determined in accordance with the food weight W detected by a weighing sensor 6. The food temperature after a specified time No elapses is detected as T1 and set by a temperature probe 5, a magnetron 4 is put into operation, and a timer N begins to count time. When the count of the timer N reaches the specified time period No, the food temperature is detected as T2 and set by the temperature probe 5. In case the food temperature is below 90 deg.C, the difference between the food temperatures, i.e., the change amount T2-T1, is compared with the specified temperature change amount alpha for the specified time period No corresponding to the abnormal temperature change rate, and when it is judged that the change rate of the detected temperatures is at the level of the abnormal temperature change rate, the controls of a power source element 9 is stopped to stop heating by microwave, and an abnormal alarm is brought in action to inform an abnormal state of absence of the temperature probe.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a cooking device such as a microwave oven.

(b) Prior art Japanese Patent Application No. 1-87209 discloses that in a cooking appliance equipped with a temperature probe for detecting food temperature, the rate of change of the temperature detected by the temperature probe per predetermined time is below a predetermined value. A technology has been disclosed in which, when it is determined that the temperature probe is too small, it is determined that the temperature probe has come out of the food, and an abnormality is reported.

However, in this case, if the amount of food is quite large, it will be determined that the temperature probe has come out of the food even if the temperature probe has not come out, and an abnormality will be reported. In other words, when the amount of food is quite large, the progress of heating the food is extremely slow and the rate of increase in temperature of the food due to heating is small, and the rate of increase in the temperature detected by the temperature probe reaches a predetermined value at the same time when the temperature probe is removed from the food. It determines that the following conditions exist and issues an anomaly notification.

Furthermore, Japanese Patent Application No. 164713/1984 describes that in a cooker equipped with an infrared sensor for detecting food temperature, if the rate of change in the temperature detected by the infrared sensor per predetermined time exceeds a predetermined value, it is determined that the food temperature is large. Disclosed is a technique for determining that there is a risk of a so-called bumping phenomenon in which the food suddenly boils up, and notifying the user of an abnormality.

However, in this case, if the amount of food is quite small,
Even if there is no risk of a bumping phenomenon occurring, it is determined that there is such a risk and an abnormality notification is issued. In other words, when the amount of food is quite small, the progress of heating the food is extremely slow, and the rate of increase in temperature of the food due to heating is large, and the rate of increase in temperature detected by the infrared sensor is at a predetermined level, as in the case where there is a risk of bumping occurring. It determines that the value is higher than the value and issues an abnormality notification. In view of this point, it is conceivable to raise the above-mentioned predetermined value so that it is not determined that there is a risk of bumping occurring at a temperature increase rate of food with a considerably small amount of food. At this time, if the predetermined value is increased too much, even if there is a risk that bumping phenomenon actually occurs, it will not be possible to judge this. In a cooking appliance equipped with a sensor, when the rate of change in the temperature detected by the infrared sensor per predetermined time is determined to be below a predetermined value and is small, the food is placed out of the range that cannot be detected by the infrared sensor. A technology has been disclosed that determines this and reports an abnormality.

However, in this case, if the power N of the food is considerably large, it will be determined that the food is misaligned even if it is not misaligned, and an abnormality will be reported.

In other words, when the amount of food is quite large, the progress of heating the food is extremely slow and the rate of increase in temperature of the food due to heating is small.
Similar to when the food is placed out of alignment, it is determined that the rate of increase in temperature detected by the infrared sensor is below a predetermined value, and an abnormality is reported.

(c) Problems to be Solved by the Invention The present invention enables abnormality during food temperature detection to be correctly determined and reported without being affected by the amount of food.

(d) Means for Solving the Problems The cooking device of the present invention includes a food placement section, a food weight input means, a food temperature detection means, and a control section for controlling heating, and the control section includes the food weight input means. determining means for determining an abnormal temperature change rate based on food weight inputted from the food weight; case,
It is characterized by having a notification means for notifying an abnormality.

(e) The abnormal temperature change rate is determined based on the food weight, and when it is determined that the temperature change rate detected by the food temperature detection means is within 17 bells of the above abnormal temperature change rate, an abnormality notification is made. To correctly judge and notify abnormalities when food temperature is detected, regardless of the weight of the food.

(F) Embodiment FIG. 1 shows the structure of a microwave oven according to an embodiment of the present invention, in which a food placement part, that is, a heating chamber (3) in which food (2) is placed, is formed in the microwave oven body (1). Then, microwave heating is performed by applying microwaves from the magnetron (4) to the food (2) in the heating chamber. Further, a food temperature detection means, ie, a temperature probe (5) inserted into the food (2) to detect the food temperature, and a food weight input means, ie, a weight sensor (6) to detect the weight of the food (2) are provided. There is.

FIG. 2 shows a printed circuit board (7), which includes a control section, that is, a microcomputer (8) that controls the microwave oven, and a power supply that is turned on and off by the computer to the magnetron (4). A power element (9) and the like for controlling are arranged. The power element (9) is composed of a transistor, a triac, or the like. In this case, the power element (9) is the bin (10) (10) (10
) to the printed circuit board (7) through solder (11) (11
1 (11) is fixed, and a shape memory alloy coil (12) is attached to one bottle (10). Such coil (12) is normally in a contracted state. If an overcurrent flows through the power element (9) for some reason and generates abnormal heat, this heat is transferred to the coil (12) via the bottle (lO).
The heat is transmitted to the solder (11) (If) (11) via the bottles (10) (10) (101), and the coil (12) is transformed to extend.
It) (Ill (11) starts to melt, so the power element (9) is affected by the stretching force of the coil (12) with the solder (II) (11) (11) melted, so the printed circuit board ( 7) Removed from the power element (9)
Current no longer flows through the power element (9), thereby preventing the power element (9) from being burnt out due to excessive current flowing through the power element (9).

FIG. 3 shows the circuit of the microwave oven, with the microcomputer (8) at its center, and around it an abnormality notification section (14) consisting of a keyboard (13), a display section, and a buzzer.
), the temperature probe (5), the weight sensor (6), and the power element (9) are arranged. The computer (8) receives operation information from the keyboard (13),
Based on each input information from the temperature probe (5) and weight sensor (6), the power element (9) is turned on and off in order to control the power supply to the magnetron (4), and the abnormality notification unit (14) to drive and control.

FIG. 4 shows the flow of the control program installed in the microcomputer (8), and the operation of the microwave oven will be explained below with reference to the same figure.

Power on, A1. Step A2 is executed. In step A1, all rewritable areas in the computer (8) are initialized, and in step A2, the keyboard (13) is initialized.
), it is determined whether the heating conditions have been set and the STAT key has been operated.

When the desired heating temperature, which is the heating condition, is set on the keyboard (13) and the start key is operated, such information is input, and steps A2, A3, A4, and A5 are sequentially executed. .

In step A3, the power element (9) is controlled to start supplying power to the magnetron (4), and microwave heating is started. In step A4, use the above weight senna (6
) The detected food weight W is set. Step A5 corresponds to the determining means of the present invention, and in this step, the abnormal temperature change rate based on the detected food weight W is determined.

That is, as the predetermined time required for the food temperature to reach a predetermined temperature change α during heating, the reference time M is multiplied by the ratio W/Wo of the reference food weight WO and the above-mentioned detected food weight W (W/ Calculate Wo). Here, such a predetermined time N
It is assumed that there has been an abnormal temperature change in the food temperature when a predetermined temperature change amount α occurs in the food temperature during o [=M (W/Wo) ], and this predetermined time NO and the predetermined temperature change amount α
This relationship corresponds to the above-mentioned abnormal temperature change rate. As is clear from the above explanation, the abnormal temperature change rate is determined based on the detected food weight W.

Next, steps A6 to All are sequentially executed.

In step A6, it is determined whether or not timer N in the computer (8) is in a clear state. In step A7, the food temperature at this time, that is, before the predetermined time No has passed, is T,
The temperature is detected and set by the temperature probe (5). In step A8, it is determined whether the magnetron (4) is being driven and is oscillating microwaves. In this case,
The magnetron (4) is always in a state of oscillation after the start of heating, so step A9 is always executed after step A8. In step A9, time measurement by the timer N is started. In addition, when the desired heating temperature and desired microwave output (less than 100%) are set on the keyboard (13), microwave oscillation is intermittently performed during heating according to such output, and the microwave A based on the cessation of oscillation
Step A9a is executed instead of step 9. In step A9a, the timer N stops measuring time. In the AIO step executed next, it is determined whether the time measured by the timer N has reached the predetermined time No. In the All step, it is determined whether the current food temperature detected by the temperature probe (5) has reached the desired heating temperature.

Thereafter, steps A6, A8 to All steps are executed cyclically unless the time count of timer N reaches the predetermined time NO, and when the time limit is reached, AIO step starts with AIO step.
Steps 12\A15 are executed. In step A12, the food temperature at this time, that is, after a predetermined period of time has passed, is T.
2, detected by the temperature probe (5) and set.

At step A13, time measurement by the timer N is stopped and its contents are cleared. In step A14, it is determined whether the food temperature T2 is 90°C or less. A1
Step 5 corresponds to the comparison means of the present invention, and in this step, as described above, the difference between the food temperatures T t and T 2 detected before and after the elapse of the predetermined time NO, that is, the amount of change T
2 Tl and the predetermined time N related to the above abnormal temperature change rate
The predetermined temperature change amount α with respect to O is compared, and it is determined whether the former is smaller than the latter. In other words, it is determined whether the rate of change in the detected temperature is at the level of the abnormal rate of temperature change.

If a negative judgment is made in step A15, the above-mentioned steps A6 to All are repeated in sequence, and the food temperature before and after the elapse of the predetermined time No.
t and T2, and based on this, it is repeatedly determined whether the detected temperature change rate has reached the level of the abnormal temperature change rate.

In such a situation, when the current food temperature determined by the temperature probe (5) reaches the desired heating temperature while the negative judgment is repeated in the A15 step, the A16 step is executed and the power element (9) is controlled. The microwave heating is then stopped.

Now, if the temperature probe (5) falls out of the food (2) for some reason during the above-mentioned repetition, the temperature probe (5) will no longer touch the food (2) whose temperature increases as it heats. The temperature cannot be detected, and the amount of change T2TI due to the food temperatures T1 and T2 detected before and after the predetermined time NO has become extremely small and less than the predetermined temperature change amount α, and an affirmative determination is made in step A15. Then, step A17 corresponding to the notification means of the present invention is executed, the control of the power element (9) is stopped, the microwave heating is interrupted, and then the abnormality notification section (14)
is activated and an abnormality of temperature probe disconnection is notified.

Note that once the temperature detected by the temperature probe (5) exceeds around 90"C, the rate of temperature rise of the food slows down, and even if the temperature probe (5) remains inserted without being removed from the food,
The change zT2-T1 per predetermined time NO is at most the predetermined temperature change amount α. In this case as well, if the judgment is made in step A15, heating will be interrupted even if the temperature probe (5) is inserted correctly.
In order to eliminate such interruptions, the above A14 step is provided, and if the detected temperature exceeds 90°C,
The configuration is such that the step jumps from the A14 step to the All step so that the A15 step is not executed.

Next, a microwave oven according to an embodiment of the present invention will be described. As for the structure and circuit of such a microwave oven, referring to FIGS. 1 and 3, an infrared sensor (15) is provided as food temperature detection means in place of the temperature probe (5).

FIG. 5 shows the flow of a control program built into the microcomputer (8) in such a microwave oven, and the operation of such a microwave oven will be explained below with reference to the figure.

Each step from 81 to B4 is the same as each step from A1 to A4 above, so after turning on the power, the keyboard (13)
When the desired heating temperature is set and the start key is operated, such information is input and microwave heating is started in step B3, and the food weight W is detected and set in step B4.

Next, step B5 is executed and one second is waited for. Then, when one second has elapsed, step B6 is executed, and the infrared sensor (15) detects the current food temperature Tx.
is detected and set. In the subsequent step B7, it is determined in what range the food weight W is less than 0.5 kK and more than 0.5 kK to 2-12 kK or more. When it is determined in step B7 that the food weight W is less than 0.5, a temperature change amount of 10° C. is set in the temperature register Tw in the computer (8) in step B8, and the temperature change amount is 0.5.
If kg ~ 2-, set temperature register TW in step B9.
15°C is set to 15°C, and if the temperature is 2 or more, 20"C is set to the temperature register Tw in step B10. Here, the temperature change amount set to the temperature register Tw is based on the food weight W. for a predetermined period of 1 second to 1
If the food temperature changes by the amount of temperature change in the temperature register Tw during 0 seconds, it is determined that there has been an abnormal temperature change. The relationship with the temperature change amount represents the abnormal temperature change rate, and each of the above steps B8, B9, and BIO substantially determines the abnormal temperature change rate based on the detected food weight W, and corresponds to the determining means of the present invention. do.

The following step B11 corresponds to the comparison means of the present invention, and in the same step, the amount of change in one second between the current food temperature Tx detected in step B6 and the food temperature T one second ago, and the above-mentioned B8, The abnormal temperature change rate determined in either step B9 or BIO is compared with the amount of temperature change in the temperature register Tw, and it is determined whether the former is greater than or equal to the latter. In other words, it is determined whether the rate of change in the detected food temperature per second is at the level of the abnormal rate of temperature change. In this case, the temperature T of the food at the beginning of heating, one second before, is not detected because it is not detected, and in this case, a negative determination is made in the Bll step.

Furthermore, in the Bll step, the food temperature T2 to T at the same time is 2 seconds to 10 seconds before. As long as is detected and exists, it is determined whether the rate of change in the detected food temperature for 2 seconds to 10 seconds is at the level of the abnormal temperature change rate.

Therefore, when a negative judgment is made in the above Bll step,
Step B12 is executed, and it is determined whether the current food temperature Tx has reached the desired heating temperature.

After that, in the garden where 1 second has passed in step B5, 86
, B7, BS (or B9 or B10), Bll, B12
Each step is repeatedly executed, and when the current food temperature Tx reaches the desired heating temperature, steps B12 to 813 are executed, the control of the power element (9) is stopped, and the microwave heating is terminated. Ru.

Now, in the middle of the above-mentioned repeated execution, if the food temperature suddenly rises to the extent that a bumping phenomenon is about to occur for some reason, the amount of change in food temperature for 1 second to 10 seconds will be an abnormal temperature change. Temperature register Tw at rate
The temperature change amount is greater than or equal to the amount of temperature change within, and an affirmative determination is made in the Bll step. Thereafter, step B14 corresponding to the notification means of the present invention is executed, microwave heating is interrupted, and the abnormality notification section (14) is activated to notify the danger of bumping occurring.

Such a microwave oven performs the following processing as necessary at the beginning of heating. FIG. 6 shows the flow of a control program further incorporated into the microcomputer (8), and the processing will be explained below with reference to the same figure. First, C1
In step B4, it is determined whether the food weight W detected in step B4 is within a range of 0.5 kg or less, 0.5 kg to 2 kg, or 2 kg or more. If it is determined in step C1 that the food weight W is 0.5 kg or less, then in step C2, a temperature change amount of 15°C is set in the temperature register Te in the computer (8), and the temperature change is 0.5 kg. ~
If the weight is 2 kg, set 1 to the temperature register Te at step C3.
0°C is set, and if the weight is 2 kg or more, 5°C is set in the temperature register Te in step C4. here,
The amount of temperature change set in the temperature register Te is based on the weight of the food, and if the food temperature changes by the amount of temperature change in the temperature register Te for a predetermined period of 60 seconds, there is an abnormal temperature change. The judgment is made that That is, the relationship between the time of 60 seconds and the amount of temperature change in the temperature register Te represents the abnormal temperature change rate, and the above C2, C3, C4
Each step substantially determines the abnormal temperature change rate based on the detected food weight W, and corresponds to the determination means of the present invention.

In step C5, the food temperature Ts at the initial stage of heating is detected and set by the infrared sensor (15). Next, the C6 step is executed and 60 seconds are waited for. Then, when 60 seconds have elapsed, step C7 is executed, and the food temperature T6° at this time is detected and set.

The following step C8 corresponds to the comparison means of the present invention, and in the same step, the food temperature TS before and after 60 seconds, T6
0, that is, the amount of change T6o−Ts, and the above C2, C3,
The abnormal temperature change rate determined in any step of C4 is compared with the temperature change amount in the temperature register Te, and it is determined whether the former is greater than or equal to the latter. In JA terms, it is determined whether the rate of change in food temperature for 60 seconds is at the level of an abnormal rate of temperature change.

Therefore, if an affirmative judgment is made in step C8 above,
Return to the appropriate location in Figure 5 above.

On the other hand, if the food (2) is placed out of the detection range of the infrared sensor (15), the amount of change in food temperature for 60 seconds will be smaller than the amount of temperature change in the temperature register Te at the abnormal rate of temperature change. , a negative determination is made in step C8. Then, the C9 corresponding to the fourth notification stage of the present invention
After the step is executed and the microwave heating is interrupted, the abnormality notification section (14) is activated to notify that the food (2) is misplaced.

(G) Effects of the Invention According to the present invention, there is provided a highly safe cooking device that can detect and notify abnormalities such as disconnection of the temperature probe, risk of bumping, misalignment of food, etc. when detecting food temperature. be able to.

Moreover, the rate of abnormal temperature change required to detect such abnormalities is determined based on the weight of the food.
The above-described abnormality can be detected correctly without being affected by the weight of the food, and therefore abnormality notification can be performed while eliminating malfunctions as much as possible.

[Brief explanation of drawings]

1 to 4 relate to a microwave oven according to an embodiment of the present invention, in which FIG. 1 is a sectional view, FIG. 2 is a perspective view of a printed circuit board,
FIG. 3 is a circuit diagram, FIG. 4 is a flowchart of a control program, and FIGS. 5 and 6-1 are flowcharts of a control program in a microwave oven according to another embodiment of the present invention. (3)...Heating chamber, (5)...Temperature probe, (6
)... Weight sensor, (8)... Microcomputer, (15)... Infrared sensor.

Claims (1)

[Claims] (1) Consists of a food placement section, a food weight input means, a food temperature detection means, and a control section that controls heating, and the control section detects an abnormal temperature change rate based on the food weight input from the food weight input means. a determining means for determining, a comparing means for comparing the rate of abnormal temperature change determined by the determining means with a rate of change in temperature detected by the food temperature detecting means, and a comparing means for comparing the rate of change in temperature detected by the comparing means; 1. A cooking appliance characterized by having a notification means for notifying an abnormality when it is determined that the temperature is at an abnormal temperature change rate level.