JPH0351269B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a boiling control device for an electric stove that detects the temperature at the bottom of the cooker and controls the amount of electricity supplied to a sheathed heater, particularly for controlling the size of the cooker or boiling temperature. This invention relates to controlling the amount of electricity applied to a sheathed heater efficiently regardless of the amount of hot water.

[Prior Art] Fig. 6 is a plan view of a conventional electric stove. In the figure, 1 is a sheathed heater, 2 is a temperature sensor that detects the temperature at the bottom of the cooker placed on the electric stove, and 3 is a sheathed heater. An automatic water boiling setting switch adjusts the amount of heat generated by the heater 1, and 4 is a power switch.

In such an electric stove, energization of the sheathed heater 1 is started by inputting the power switch 4, and water is heated with the amount of heat set by the automatic water boiling setting switch 3. At this time, temperature sensor 2
The temperature at the bottom of the cooker is constantly detected, and the energization of the sheathed heater 1 is controlled so as to output a set amount of heat based on the temperature detection signal from the temperature sensor 2. Water filled in a cooking device such as a cooking device, a kettle, or a pot is heated and controlled by a sheathed heater 1 whose electricity is controlled until it boils.

[Problems to be Solved by the Invention] However, in the boiling control of conventional electric stoves, the power applied to the sheathed heater is reduced after boiling is detected by a temperature sensor. There was a problem with it boiling over.

Figure 7 is a graph showing the changes in the water temperature and the temperature at the bottom of the cooker when water is boiled on a conventional electric stove.As is clear from the figure,
The temperature of the hot water remains constant at 100℃,
The temperature at the bottom of the cooking pan is well over 100 degrees Celsius, causing it to be unnecessarily heated. Therefore, there was a problem that the water filled in the cooker evaporated unnecessarily and that electric power was wasted.

In addition, the control when boiling water differs depending on the amount of water, and it is difficult to achieve good boiling control with conventional cookers of various sizes and uniform control regardless of the amount of water. It is.

This invention was made in order to solve such problems, and it eliminates overheating of the cooker even when the size of the cooker and the amount of water are different, and provides efficient power supply control to the sheathed heater. The purpose of the present invention is to obtain a boiling control device for an electric stove that can perform the following functions.

[Means for solving the problem] The boiling control device for an electric stove according to the present invention includes:
Maximum power energization means detects the gradient of temperature rise of water between predetermined temperatures, calculates the duration of maximum power energization, and energizes the maximum power until the end of this duration, and the detected temperature of the bottom of the cooker. temperature determination means for comparing the detected temperature with a predetermined temperature and determining whether or not the detected temperature is at a higher level than the predetermined temperature; If the gradient of the temperature rise is smaller than the selected gradient determined as the selection point of the control method after the maximum power energization ends, the first partial energization is performed until the temperature rise gradient reaches a boiling gradient that is considered to be a boiling state. a partially energizing means;
The temperature determining means determines that when the detected temperature is at a lower level than the constant temperature and the gradient of temperature rise is greater than the selected gradient at the end of maximum power application, a predetermined adjustment is made to reach a boiling state. a second partial energization means for partially energizing for a time;
When the detected temperature after the start of energization to the sheathed heater is higher than the predetermined temperature, the temperature determining means detects the gradient of temperature rise between the predetermined temperatures at two locations, and the ratio of the gradients is determined to be boiling. third partial energization means that energizes at the maximum power until a predetermined ratio is reached to prevent the boiling point from being exceeded; It is characterized by

In this way, the gradient of temperature rise determined by each energizing means indicates the heating characteristics of the sheathed heater depending on the size of the cooker and the amount of water, and by detecting this gradient of temperature rise, various This allows for good boiling control that is compatible with different types of cookers and various amounts of water.

[Function] According to the above configuration, the power supplied to the sheathed heater is reduced before the boiling point, and when the temperature rise is small, the gradient of the temperature rise is so gentle that it can be considered that the boiling point has been reached. Partial energization control is performed until the slope is reached. In addition, when the temperature rise gradient is large, partial energization is controlled for a relatively short adjustment time to prevent overheating, and regardless of the size of the cooker or the amount of water, the sheathed heater is heated at approximately the boiling point of the cooker. Stop energizing. With such control, the remaining heat of the sheathed heater when the maximum power is being applied can be effectively used as the heating amount for boiling.

[Embodiment] FIG. 1 is a circuit diagram showing one embodiment of the present invention, and 1 to 4 are the same as the conventional device.

In the figure, 5 is a heat-sensitive element in the temperature sensor 2;
Reference numeral 6 denotes a microcomputer, which operates maximum power energization means, first partial energization means (A route control), second partial energization means (B route control), and third partial energization, which are the characteristic components of the present invention. means (C route control). Then, the detection signal of the temperature sensor 2 and the output signal of the automatic water boiling setting switch 3 are input. 7 is a transistor, 8 is a photocoupler, and the photocoupler 8 is turned on and off by turning on and off the transistor 7 based on a control signal output from the microcomputer 6.
is activated to control the energization of the sheathed heater 1. 9 is a DC power supply, 10 is a thyristor that performs rectification, 11 is a commercial power supply, and 12 is a buzzer that notifies you that the water has boiled.

The embodiment has the above-described configuration, and its operation will be explained based on the flowchart shown in FIG.
Note that Figures 3, 4, and 5 are graphs showing the state of water temperature when boiling is controlled;
In the case of route A control shown in the figure, FIG. 4 shows the case of route B control shown in FIG. 2, and FIG. 5 shows the case of route C control shown in FIG.

In FIG. 2, first, when the power switch 4 is turned on, temperature detection is performed in step (13).
Further, when the automatic water boiling setting switch 3 is input, the heating power is maximized in step (14), that is, the maximum power is turned on.

Next, in step (15), H seconds have passed (for example, 30 seconds) after the automatic water boiling setting switch 3 has been input.
, and the process proceeds to step (16) to determine whether or not the detected temperature T ₁ is greater than a predetermined temperature T ₂ (which is a branch temperature to be described later). In the embodiment, this predetermined temperature T ₂ is approximately 45
If T ₁ ≧T ₂ , the process moves to step (37), and if T ₁ <T ₂ , the process moves to step (17).

In step (17), the gradient of the water temperature rise between predetermined temperatures is detected to calculate the maximum power energization duration _H2 , and as shown in route A control in Figure 3, the temperature T ₃ (e.g. 62.6℃)
First, find the time H ₁ required to reach T ₄ (for example, 77.0°C). This required time _H1 is a value indicating the gradient of temperature rise, and based on this temperature rise gradient, the boiling temperature is
Maximum power continuation time before reaching 100℃
Calculate _H2 . Then, based on this duration _H2 , the maximum power is continued to be energized.

Next, in step (18), it is determined whether the gradient of the temperature increase is greater than the selection gradient determined as the selection point of the control method, and the required time _H1 indicating the gradient of the temperature increase is greater than the selection gradient. A determination is made as to whether or not the predetermined time shown is greater than H ₃ (H ₃ <
Determination of _H1 ). In other words, if the temperature increase gradient is smaller than the selected gradient, the control method using the first partial energization means (route A) is performed, and if it is larger, the control method using the second partial energization means (route B) is performed. . Therefore, if H ₃ <H ₁ , the process moves to step (19) where A route control is performed, and if H ₃ ≧H ₁ , the process moves to step (19) where B route control is performed. In this step (29), the heating time from the temperature _T4 is measured, and it is determined in step (20) whether or not the heating time _H4 has elapsed for the duration _H2 . i.e. step(20)
Then, it is determined whether the heating time H ₄ is greater than the duration H ₂ or not. If H ₂ > H ₄ , the process returns to step (19), and if H ₂ ≦H ₄ , the process returns to step (21). )
Then, partial energization is performed to reduce the heating power to A%, for example 70%.

In route A control, since the temperature increase gradient is originally small, it takes time to reach the boiling temperature, so the temperature increase gradient is further detected and partial energization is performed until the boiling gradient is reached, which can be regarded as the boiling temperature. That is, in step (23), the temperature _T5 of the cooking bottom is further detected, and then, in step (24), the time _H6 after partial energization is measured.

In step (25), the time after this partial energization is
It is determined whether or not H ₆ is greater than a predetermined time value H _7. If H ₆ < H ₇ , the process returns to step (24), and if H ₆ ≧ H ₇ , the process proceeds to step (26). and detect the temperature _T6 at that time.

Then, in step (27), it is determined whether the difference between the two detected temperatures, that is, T ₆ - _{T 5} is greater than the temperature T ₇ representing the boiling gradient. and,
If T ₆ −T ₅ ≦T ₇ , the temperature at the bottom of the cooker has reached a temperature corresponding to the boiling temperature, and the buzzer sounds in step (28). On the other hand, if T ₆ −T ₅ > T ₇ ,
Proceeding to step (33), the temperature increase gradient is further detected.

That is, in steps (33) to (36), the same boiling gradient detection action as described above is performed, and the difference between the newly detected detected temperature T ₈ and the detected temperature T ₆ is higher than the temperature T ₇ indicating the boiling gradient. If it is small, proceed to step 28 and sound the buzzer. If this temperature difference T ₈ -T ₆ is larger than the temperature T ₇ , the process returns to step (26) and the temperature increase gradient is further detected.
This operation is repeated as many times as the temperature rise gradient reaches a boiling gradient, and only when the boiling gradient is reached is a buzzer alerting the user that the water has boiled. Note that after the buzzer notifies the temperature, the current is continued at a small amount of power to maintain the temperature at 100°C, which is 400W in the example.

Next, the second partial energization means (B route control) after maximum power energization will be explained.

In step (18), the temperature rise gradient is divided into cases where it is low and high, but when the temperature rise gradient is larger than a predetermined value, that is, when H ₃ ≧ H ₁ , the process moves to step (29). The maximum power is continued for the duration _H2 determined in step (17).

Then, after the duration _H2 has elapsed, partial energization is performed in step (30) to reduce the heating power to A%, which in the example is 70%. In the case of this B route control,
Since this is a case where the temperature increase gradient is large, the time required to reach the boiling temperature is extremely short and the time can be easily estimated, so a buzzer indicating the end of boiling is sounded after the adjustment time _H7 . Therefore, in step (31), the time _H9 from the start of partial energization is measured, and in step (32) it is determined whether or not this time _H9 has reached the adjustment time _H7 . H After ₇ hours, the buzzer will sound after 30 seconds in the example.

As shown in Figure 4, when the gradient of temperature rise is large, the time to reach boiling temperature is extremely quick, and by ending the partial energization for temperature rise before the boiling point, it is possible to overheat the cooker. It is possible to prevent heating and maintain a good boiling state of hot water.

Next, in the example, C route control is performed when the starting temperature for boiling water is high;
According to the route control, a temperature rise curve as shown in FIG. 5 is drawn. Since the time required for the temperature of water to reach a boiling state is short in this C route control, the heating time at the maximum power is not calculated, and control is performed based on the gradient ratio.

In the step (16), it is determined whether the detected temperature T ₁ is higher than the predetermined temperature T ₂ (45°C), and when T ₁ ≧T ₂ , the process moves to step (37) and the temperature T 1 is determined. Measure the required time H ₁₀ from ₉ to T ₁₀ . Then, in step (38), the time _H11 required for the temperature to rise by a predetermined temperature _T11 from temperature _T10 is measured, and in step (39), _aH10 and _H11 are compared.

That is, in step (39), the slope ratio a is multiplied by the time _H10 , and it is determined whether the value of this _aH10 is greater than the time _{H11.If aH10} ≦ _H11 , the step (30) and heating power to 70
Perform partial energization to %. After that, as described above, partial energization is performed for the adjustment time _H7 , and then the buzzer is sounded.

If aH ₁₀ >H ₁₁ , the process moves to step (40) and the temperature detection as described above is performed once again. That is, for example, from the detected temperature T ₁₂ to the predetermined temperature
The time _H12 required for the temperature to rise by _T11 is measured at step (41).

Next, in step (42), it is determined whether aH ₁₂ is greater than H ₁₁ in the same way as in step (39), and if aH ₁₁ ≦H ₁₂ , the process moves to step (30) and the partial processing is performed. Turn on electricity. Also aH ₁₁ >
If H ₁₂ , the process returns to step (40) and temperature detection is performed again.

In this way, the C route control is such that when the water temperature is high when the electric stove is input, electricity is applied at maximum power until the predetermined temperature increase gradient reaches a predetermined ratio, and after reaching the predetermined ratio, the boiling point is reached. Partial energization is performed only during the adjustment time.

[Effects of the Invention] As explained above, this invention calculates the maximum power energization duration from the temperature rise gradient, and after the maximum power energization for this duration ends, different types of electricity are calculated depending on the magnitude of the temperature rise gradient. Since partial energization is performed, overheating caused by the sheathed heater can be prevented and a good boiling state can be obtained.

Further, since residual heat generated by applying maximum power can be effectively used, it is possible to reduce power consumption when boiling water.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the boiling control device according to the present invention, Fig. 2 is a flowchart showing the operation of the inventive device, and Fig. 3 is a graph showing the temperature rise of water by route A control. Figure 4 is a graph showing the temperature rise of water due to route B control, Figure 5 is a graph showing the temperature rise of water due to route C control, Figure 6 is a plan view of a conventional electric stove, and Figure 7 is a graph showing the temperature rise of water due to route B control. The figure is a graph showing the rise in water temperature and the temperature at the bottom of the cooker in a conventional electric stove. In the figure, 1 is a sheathed heater, 2 is a temperature sensor, 3 is an automatic water heating setting switch, 4 is a power switch, and 6 is a microcomputer including maximum power supply means and first and second partial power supply means. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In a boiling control device for an electric stove that detects the bottom temperature of the cooker and controls the amount of electricity supplied to the sheathed heater in order to boil water, the gradient of the temperature rise of water between predetermined temperatures is detected. A maximum power energization means calculates the duration of maximum power energization by calculating the maximum power energization time, and energizes the maximum power until the end of this duration time, and compares the detected temperature of the bottom of the cooker with a predetermined temperature, and determines that the detected temperature is temperature determining means for determining whether the temperature is at a higher level than a predetermined temperature; and a temperature determining means for determining whether or not the detected temperature is at a level lower than the predetermined temperature and at the end of maximum power application. If the gradient is smaller than the selected gradient determined as the selection point of the control method, a first partial energization means performs partial energization until the temperature increase gradient reaches a boiling gradient that is considered to be a boiling state, and the temperature determining means, When the detected temperature is at a lower level than the predetermined temperature and the gradient of temperature increase is greater than the selected gradient at the end of maximum power energization, partial energization is performed for a predetermined adjustment time to reach a boiling state. When the detected temperature after the start of energization to the sheathed heater is at a higher level than the predetermined temperature, the second partial energization means and the temperature determination means determine the gradient of temperature increase between the predetermined temperatures at two locations. A third method that energizes at maximum power until the detected slope ratio reaches a predetermined ratio that does not exceed the boiling point, and after reaching the predetermined ratio, partially energizes for a predetermined adjustment time to reach a boiling point. A boiling control device for an electric stove, characterized by comprising: a partial energization means; and a boiling control device for an electric stove.