JP2537978B2 - Stew cooker - Google Patents

Description

TECHNICAL FIELD The present invention detects internal boiling when cooking cooked food or boiling hot water by using a gas or an electric stove, by detecting a change in vibration of a container, and by this change in vibration, The present invention relates to a stew cooker that prevents the sticking of food.

Conventional technology When cooking with a stove, when the inside boils, the heating power is reduced to simmer for a long time. If this timing is delayed, a spill will occur. Also, when boiling water, it will boil if it does not stop at the same time as boiling. In this way, the boiling judgment must be made instantaneously.

In addition, in boiling cooking, if the boiling power is boiled and the heating power is reduced and the heating is not completed and the heating power is not reduced at a suitable time, not only burning will be wasted but cooking will be wasted, and the pot will be damaged. Depending on the type of cooking, ingredients, and quantity, the time for this stewing may vary depending on the type and ingredients of cooking, such as stew, which may be completed with a lot of water remaining, or stew, which may be heated to the point of burning. is there.

In this way, stew cooking is extremely difficult to judge for boiling and scorching, and a person must always monitor it by himself, and anyone has experienced failure such as spilling or scorching.

Therefore, attempts have been made to automatically determine boiling. However, the boiling point of water is 100 ° C under normal atmospheric pressure, and if it is a little lower than this temperature, it will not boil, and it will not reach a temperature of 100 ° C or higher unless the water content disappears. Further, since these cookings are usually put in a container such as a pan for cooking, there are many restrictions such as the need to accurately detect the temperature in the pan.

As a means for solving this, a means as described in JP-A-58-45414 has been proposed. This configuration is shown in FIG. This focuses on the fact that the temperature of the bottom of the pan does not rise when the cooking inside has boiled and the temperature rise disappears. In Fig. 10, an example of a gas table stove is shown. As shown in the figure, the temperature sensor 2 configured to contact the outer bottom surface of the pan 1 measures the temperature of the bottom of the pan, the inclination detector 3 measures the inclination of the temperature rise, and the bending point detector 4 determines the inclination of the temperature rise in advance. The fuel control unit 5 controls the thermal power by detecting a bending point that is equal to or less than the specified value. In the figure, 6 is a gas inlet, 7 is a burner, and 8 is a control valve for varying the amount of gas flowing through the burner 7 to control the combustion amount of the burner 7.

With this configuration, it becomes possible to detect internal boiling almost accurately.

However, in the configuration shown in FIG. 10, a cooked material such as a kettle that has no viscosity and easily causes convection inside is used, and a container with good heat conduction such as an aluminum pot is used. In the case, there is no problem, but in cooked foods with high viscosity such as curry or stew, boiling is detected even when the portion near the heating portion is boiling and the portion far from the heating portion is not boiling yet. Also, when a container with poor heat conduction such as a clay pot or a glass pot is used, the temperature of the sensor will continue to rise even if the internal temperature rises due to boiling, and it will not be possible to detect boiling. There were challenges.

In addition, the temperature starts to rise again when the water content inside is lost even in the case of stew cooking, but even in this case, the temperature of the sensor changes when using a pot with poor heat conduction or when cooking with poor convection. It takes time to do
There was a problem that the detection of burning was delayed.

Therefore, it is an object of the present invention to provide a stew cooker capable of detecting the vibration of bubbles generated at the time of boiling with a vibration sensor in contact with a pot and detecting boiling and burning.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a cycle measuring unit that measures a vibration cycle from a vibration sensor, and a vibration cycle measured by the cycle measuring unit in a predetermined first state. When the temperature rises, a boiling detection unit outputs a signal, a heating control unit that drives the heating device by the signal of the boiling detection unit to control the heating power to a preset value, and then the vibration cycle is preset. The burnt-in detection unit that detects the second state and the safety control unit that stops heating according to the signal from the burnt-in detection unit are provided.

With the above configuration, the vibration of the container due to the bubbles generated when the inside is boiled is detected, the boiling is detected when this vibration state occurs under a certain condition, and after detecting this boiling, the cooking is performed. When it is detected that the internal water content has disappeared and the vibration has decreased, it has the action of stopping the heating, assuming that burning has started.

Embodiments Embodiments of the present invention will be described below with reference to FIGS. 1 to 9.

First, the first system for boiling detection according to the present invention will be described with reference to FIG. Similar to FIG. 10, an embodiment applied to a gas table stove is shown, and the same operation parts are given the same numbers. The gas flows in through the inlet 6, passes through the control valve 8, and is burned in the burner 7. Reference numeral 1 is a pot containing cooked food inside, which is heated by a burner 7. Reference numeral 9 is a detection bar having one end in contact with the pot 1 and the other end provided with a vibration sensor 10. The vibration sensor 10 is a generally known ultrasonic sensor, microphone, or acceleration sensor. Here, an example using an acceleration sensor having a configuration in which impedance changes due to vibration will be described.

The signal from the vibration sensor 10 is a cycle measurement unit 12 of the controller 11.
, And measure the period of vibration. Vibration sensor 10
Is shown in FIG. The horizontal axis of FIG. 2 represents time t, and the vertical axis represents the signal output of the vibration sensor 10. The portion A is in a state before boiling, and there is no periodic vibration. The part B in the figure is the vibration generated when the food is stirred or the ingredients are added. When the inside boils, bubbles are generated and a periodic vibration signal is obtained as in the C part. The cycle measuring unit 12 measures the time interval Δt of this vibration. The boiling detection unit 13 in FIG. 1 is a cycle measurement unit 12
The comparator 15 drives the timer 16 when the period T measured in step 4 becomes a preset period range 14, and when the vibration continues for a certain period of time, it is determined to be boiling. If the timer unit 16 does not continue to vibrate for a certain period of time, it is determined that the disturbance is not boiling but some kind of disturbance, and waits until the vibration occurs again. When boiling is detected by the boiling detection unit 13, a signal is output to the heating control unit 17, and here the control valve 8 is driven so as to control the heating power according to the cooking. For example, in the case of boiling water, heating is stopped, some warning output is output, and boiled dishes, cooked rice, etc. are squeezed to an appropriate heating power to continue heating.

FIG. 3 shows a specific circuit diagram of the main part. A bridge circuit is constituted by the vibration sensor 10 and the resistors 18, 19, 20 and its midpoint potential is amplified by an inverting amplifier 21 (here, it is constituted by an operational amplifier 22 and resistors 23, 24). This output is waveform-shaped by a waveform shaper 25 and input to a microcomputer (hereinafter referred to as a microcomputer) 26. The waveform shaper 25 compares the electric potential ea with the electric potential ec by the comparator 27 and shapes the rectangular wave. Resistance 28
The capacitor 29 is an integrating circuit that absorbs fine fluctuations of the sensor 10. Figure 4 shows the waveforms of the potentials es and ea, eb, ec. The microcomputer 26 uses this input and the heat power setting switch 30
The output ef is output according to the value set in, and this value is D / A
The converter 31 converts the analog electric potential eg and the amplifier 32 amplifies the electric potential to drive the control valve 8. The control valve 8 will be described here as an example using an electromagnetic gas proportional control valve that continuously controls the gas flow rate according to the current value I flowing in the electromagnetic coil.
It may be an on / off valve, a multistage valve, or a motor valve. Therefore, the amplifier circuit 32 receives the coil current I according to the potential eg.
Variably controlled.

Until the food is boiled, it is heated to maximum heat and boiled quickly. Therefore, the current I becomes the maximum current. When the microcomputer 26 detects the boiling by the operation described later by the input eb, the switch 30 switches to the heating power set according to the cooking. In this example, it switches to medium heat, low heat, and digestion. This may be manually set or automatically set. The switch 33 is an operation switch, and when the switch 33 is turned on, the potential ed becomes low, and the microcomputer
When this is detected at 26, the control valve 8 is opened and an output for driving an igniter (not shown) is output. Conversely, when ed becomes high, the control valve 8 is closed and the burner is extinguished. The output ej is an output that drives the buzzer 34 for detecting boiling, when the cooking is completed, or when any abnormality occurs, and the output drives the oscillation circuit 35 for the buzzer. Sound buzzer. 36 is a DC power supply for supplying power to the entire circuit. In FIG. 3, only the circuits of the main part are shown. For this reason, the clock circuit of the microcomputer 26 and other circuits are omitted.

Next, the microcomputer 26 that performs boiling detection, which is the main point of the present invention,
The operation will be described with reference to the flow charts of FIGS. 5 and 6. In the figure, the same numbers are added to the side of the flow that performs the same operation as in FIG. When the operation switch is turned on in FIG. 5, the control valve 8 is opened and the burner 7 is ignited to start heating. After that, the signal eb from the vibration sensor 10 is input, and the vibration cycle Δt is measured by the operation of the cycle measuring unit 12 described later. At this time, when there is no boiling immediately after heating, a clear cycle does not occur as in part A of FIG. 2 and Δt is not determined. At this time, this loop I is repeated until it returns to the start and the operation switch is turned off.

When the internal boiling starts and Δt is determined, the comparing section 15 compares the value of Δt with a predetermined set period Δts. The period Δt has a large value because the generation of bubbles is slow in the partial boiling at the initial stage of boiling. Therefore Δt
If is larger than Δts, it is returned through the loop of II. When Δt ≦ Δts is satisfied, the timer of the timer unit 16 starts and waits for a predetermined time to elapse in the loop of III. During this time, the measurement of Δt is continued, and when Δt is no longer determined, Δt ≦ Δts
When the above condition is no longer satisfied, the process returns to the loop of I or II, and the disturbance described in FIG. When the timer elapses a predetermined time, it detects that the inside has boiled for the first time and detects boiling, and outputs a notification output, switching of heat power, or output of digestion as needed.

FIG. 6 is a flow chart for explaining a subroutine for operating the cycle measuring unit 12. The vibration input eb is at a high level here when there is no vibration output as described in FIG. Therefore, the input eb returns without any action until it goes low. When the input eb becomes low level, the time measurement for measuring Δt is started, then the input eb is waited for becoming high, and the process is returned. input
When eb returns to the high level, the flag F is switched to the "1" level and the input eb waits for the low level again. At this time, since the input eb is at the high level, the check V of the flag F is provided to prevent the flow from being returned in the first flow IV section. Initially, the flag F is at "0" level, so that the flow is returned as it is, but when the input eb once becomes high level and the measurement of Δt is started, the flag F is set to the "1" level and the Δt measurement is continued. I have to.

Next, when the input eb becomes low level again, the measurement of Δt is stopped and Δt is determined. At this time, the flag F is reset to "0" in preparation for the next measurement. As described above, the vibration cycle Δt measures the time of one cycle from the input eb being the low input to the high input and then the low input again.
Various methods other than this method are conceivable as specific means for measuring Δt. Also, it can be easily applied even if the input eb is inverted high / low depending on the circuit configuration.

FIG. 7 is a block diagram for explaining another embodiment of boiling detection, in which the configuration of the controller 11 is different from that in FIG. In FIG. 7, parts that operate in the same manner as in FIG. 1 are given the same numbers.

In the boiling detection section 13 in the figure, the cycle change measuring section 37 measures the change state of the cycle Δt of the cycle measuring section 12. The relationship between the cooking state and the vibration period Δt is shown in FIG. Similarly to FIG. 2, in part A of FIG. 8, the vibration period Δt becomes smaller from infinity to boiling before boiling. The cycle Δt becomes a stable value when boiling occurs in the C part, but when the internal water is exhausted, the generation of bubbles due to boiling decreases, so the cycle Δt decreases.
When t becomes large again and becomes charred, it becomes infinity again.

For this reason, the determination unit 38 in FIG. 7 determines that the inside has boiled when the period change Δdt of the period change measurement unit 37 becomes smaller than the period change set value 39 Δdts. Period change measurement unit
Various configurations can be considered for the configuration of 37, such as a configuration for measuring the changing state of the period Δt at regular time intervals and a configuration for calculating by the difference or ratio of the values of the period Δt measured each time. Further, the determination unit 38 may be configured to determine boiling when Δdt is smaller than a constant value Δdts and the change is stable.

Now, FIG. 9 shows an embodiment of the stew cooker of the present invention, and the controller 11 has a boiling detection unit 13 and a burning detection unit.
40 and a safety control unit 41 are provided. Boiling detector 13
In the configuration described with reference to FIGS. 1 and 7, the first state 42, which is the determination value, is the boiling determination condition described with reference to FIGS. 1 and 2.

Here, after the boiling judgment, drive the burning detection unit 40,
Even after the heating amount is controlled by the heating control unit 17 (the heating power is reduced), the vibration cycle Δt is continuously measured to detect the burning.
When the burning occurs, the vibration period Δt increases again as described with reference to FIG. 8D. Therefore, the vibration period Δt is detected. The specific means of detection is that the value of Δt after the boiling is detected is increased to a certain level (the second state 4
3) A structure that determines when the above is determined to be non-stick, or Δt
Various configurations similar to those described in the boiling detection are conceivable, such as a configuration in which it is determined that the change state of the state of increasing becomes charring.

When the scorching detection unit 40 determines scorching, a signal is output to the safety control unit 41 to stop combustion or notify. This configuration is effective in preventing burning due to many burning failures, since boiling is continued for a long time until there is almost no water in a low heat after boiling, especially when cooking boiled potatoes and the like.

In this embodiment, the present specification is configured to detect boiling and charring by changing the vibration cycle of the vibration sensor, but other than this, means for detecting a change in vibration amplitude, means for detecting a change in vibration frequency, and sound. Various means such as a means for detecting a change in the are possible and can be realized by applying the present invention.

 In addition to gas stoves, it can be applied to electric stoves, ovens, microwave ovens, etc.

Effects of the Invention As described above, the stew cooker of the present invention measures the vibration cycle of the vibration sensor configured to contact the cooking container to be heated,
When the vibration cycle reaches a predetermined first state, boiling is detected and the heating amount is controlled to a predetermined set value, and when the vibration state becomes the second state, the burning detector stops heating, Not only the spillage caused by boiling can be prevented, but also the non-sticking can be prevented, and the cooking process can be prevented from failing, allowing safe and secure cooking.

[Brief description of drawings]

FIG. 1 is a control block diagram of a gas stove for explaining an embodiment of the present invention, FIG. 2 is a vibration waveform diagram of a vibration sensor, FIG. 3 is a circuit diagram of a main part of a detection circuit portion of the vibration sensor, and FIG. Third
Waveforms of respective parts in the figure, FIGS. 5 and 6 are flowcharts for explaining the operation of the main part, FIG. 7 is a control block diagram for explaining another embodiment of the controller part, and FIG. 8 is vibration during cooking. FIG. 9 is a control block diagram for explaining a change in cycle, FIG. 9 is a control block diagram for explaining a cooked food cooker to which the present invention is applied, and FIG. 10 is a control block diagram for explaining a conventional boiling detection device. 1 …… pan (cooking vessel), 7 …… gas burner (heating device), 10 …… vibration sensor, 11 …… controller, 12 ……
Period measurement unit, 13 …… Boiling detection unit, 15 …… Comparison unit, 16 ……
Timer section, 17 ... Heating control section, 37 ... Period change measurement section,
38 ... Judgment unit, 40 ... Burning detection unit, 41 ... Safety control unit, 42 ... Predetermined first state, 43 ... Predetermined second state, .DELTA.t ... Vibration cycle .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Hirata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-63-121588 (JP, A) JP-A-4- 503397 (JP, A) JP 62-129648 (JP, A) JP 56-100234 (JP, A) Actually opened 55-119020 (JP, U)

Claims (1)

(57) [Claims] 1. A vibration sensor configured to be in contact with an outer surface of a cooking container heated by a heating device, a cycle measuring section for measuring a vibration cycle from the vibration sensor, and a vibration cycle measured by the cycle measuring section in advance. A boiling detection unit that outputs a signal when the predetermined first state is reached, and a heating control unit that drives the heating device by the signal of the boiling detection unit to control the heating power to a predetermined set value, After that, the stew cooker is composed of a controller that includes a scorching detection unit that detects that the vibration cycle has reached a predetermined second state, and a safety control unit that stops heating according to a signal from the scorching detection unit.