JP2001061660A - Electric kettle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To add, to an electric kettle, the function for not breaking a power source breaker even when it is used for heating together with other high-power apparatuses. SOLUTION: This electric kettle has a heating control system 6 which supplies power to a heating means 5 to heat a liquid in a container 2, and a power monitor 9 to detect the voltage of the commercial power. When electric power is supplied to the heating means 5 through the heating control means 6, if the voltage of the commercial power, detected with the power monitor 9, is lowered from a standard for heating time by a margin equal to or more than a predetermined value for heating time, the heating control means 6 stops the power supply to the heating means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater that keeps warm by boiling water.

[0002]

2. Description of the Related Art A conventional general electric water heater will be described below. FIG. 6 shows a configuration block diagram. 1 is a main body of an electric water heater, 2 is a container containing a liquid to be heated,
Reference numeral 3 denotes a lid body that opens and closes when a liquid is put into the container 2. Reference numeral 4 denotes a temperature sensor that detects the temperature of the liquid in the container 2. Reference numeral 5 denotes a heating unit including a high wattage main heater and a low wattage auxiliary heater. Heating control means consisting of a relay for supplying power to the means 5 and its driving circuit, control means 7 for controlling the operation of the heating control means, and operation means 8 consisting of a switch for instructing the operation by the user. The operating means 8 can be used to instruct re-boiling during warming, setting of the warming temperature, and setting of a timer.

In such an electric water heater, usually,
The water in the container 2 is heated by the main heater and the auxiliary heater of the heating means 5, and when the boiling point is detected by the temperature sensor 4, the control means 7 switches to only the auxiliary heater of the heating means 5 by the heating control means 6 to set the temperature. Temperature control is performed to maintain the set temperature.

When it is desired to boil the hot water while keeping the temperature, the reboil switch of the operating means 8 is pressed, and the control means 7 is heated by the heating control means 6 by the main heater of the heating means 5 and the boiling point is detected by the temperature sensor 4. When it is detected, it switches to the auxiliary heater of the heating means 5 and controls the temperature so as to maintain the set temperature.

When setting a timer, a timer setting switch of the operation means 8 is pressed to set a timer time. The control means 7 stops the energization of the main heater of the heating means 5 during the timer, and controls the temperature by the auxiliary heater. In this case, the heat retaining temperature is about 60 degrees. When the timer expires, the control means 7 heats with the main heater of the heating means 5 by the heating control means 6, switches to the auxiliary heater of the heating means 5 when the boiling point is detected by the temperature sensor 4, and is set before the timer shifts. Temperature control is performed so as to maintain the heat retention temperature.

[0006]

However, since electric water heaters of recent years have a high output of 1 KW or more, if the same power supply breaker as another high-output device, for example, an electric rice cooker, is used, the power supply breaker is cut off. There is a risk that it will. If the user is present, the power breaker can be returned immediately and the effect is small, but if the user is sleeping, the effect is large. For example, if the timer setting of the electric rice cooker overlaps while the electric water heater is boiling, the power breaker shuts off when the electric rice cooker returns to the timer, and the rice is not cooked when the user wakes up in the morning. There is a defect.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a heating means for heating a liquid in a container, a heating control means for supplying power to the heating means, and a detection of a value of a commercial power supply voltage. The power supply monitor has a power supply monitor, and the control means, when the heating means is energized by the heating control means, the commercial power supply voltage value of the power supply monitor is reduced by a predetermined heating time predetermined value from a predetermined heating reference value. In this case, since the heating control unit controls to stop the energization of the heating unit, it is possible to detect that another device has started the high-power operation, and to stop energization of the heating unit. Can be prevented.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION
Heating means for heating the liquid in the container, heating control means for supplying power to the heating means, and a power supply monitor for detecting the value of the commercial power supply voltage, the control means when the heating means by the heating control means to energize the heating means When the commercial power supply voltage value by the power supply monitor decreases by a predetermined value at the time of heating given from the predetermined value at the time of heating, the control by the heating control means to stop the energization of the heating means. Since it is possible to detect that the device has started the high-output operation and stop the energization of the heating means, it is possible to prevent the power supply breaker from being shut off.

According to the invention described in claim 2 of the present invention, the control means stores the commercial power supply voltage value by the power supply monitor when the heating means is energized by the heating control means as a new heating reference value. The commercial power supply voltage value when the heating means of the actual electric water heater is energized can be used as the reference value.

According to the third aspect of the present invention, when the heating means is energized by the heating control means, the control means drops the commercial power supply voltage value by the power supply monitor from the heating reference value by a predetermined value or more during heating. In this case, since the output of the heating means is reduced by the heating control means, it is possible to prevent the power breaker from being shut off, to prioritize the use of other high-power devices, and to enable the simultaneous use of an electric water heater.

According to the invention of claim 4 of the present invention, since the heating predetermined value setting means capable of setting the predetermined value at the time of heating to an arbitrary value is provided, the electric water heater and the electric water heater can be used in different power supply environments depending on each home. It is possible to set a predetermined value at the time of heating that is optimal for a combination of other high-power devices used simultaneously.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiments, the same reference numerals are given to the same components as those described in the conventional example described above, and description thereof will be omitted.

FIG. 1 shows a power supply monitor 9 for detecting the value of the commercial power supply voltage. FIG. 2 shows a circuit diagram of the power supply monitor. DC5V constant voltage DC power supply VD
D and a circuit based on one phase of a commercial AC power supply having the same reference, are composed of resistors R1 to R3, a Zener diode ZD, and diodes D1 and D2.
Is being entered. The waveform at the point V is a waveform in which a half-wave of the AC voltage is clipped by the diode D2 as shown in FIG. Further, the voltage Vin at the point V is a value represented by the following equation.

[0014]

(Equation 1)

R1 = 560KΩ, R2 = 300K
Ω, R3 = 39 KΩ, Vz = 112 V, and VDD = 5 V.

The control means 7 measures the peak value from the AC zero-cross point to the next zero-cross point for each half-wave of the AC power supply and performs AD conversion. As a result, the voltage Vin becomes DC5V
Is divided into 255 bits. FIG. 4 shows a comparison table between the commercial AC power supply voltage and the AD conversion value. For example,
When the commercial AC power supply voltage is 100 V in effective value, the voltage Vin at point V is 2.54 V, and the value obtained by AD conversion of this is 1
The value becomes 30 bits. The control means 7 detects the commercial AC power supply voltage value based on a predetermined detection threshold value. For example, when the detected value is 110 bits, it is determined that the power supply voltage is 96V. The control means 7 determines the commercial AC power supply voltage value by averaging the ten AD conversion values. Commercial AC power supply is 50H
In the case of z, one measurement time is about 20 ms.
It takes about 0.2 seconds to determine the value based on the average value of the times. Thereafter, the control means 7 continues the measurement and determines the latest voltage value about every 0.2 seconds.

In the electric water heater provided with such a power supply monitor 9, a value corresponding to 98V as a reference value at the time of heating and 4V as a predetermined value at the time of heating is given to the control means 7 in advance.

First, when the user puts water into the container 2 and turns on the power, the control means 7 causes the heating control means 6 to start energizing the main heater and the auxiliary heater of the heating means 5. Then, the control means 7 determines the commercial AC power supply voltage by the power supply monitor 9 in about 0.2 seconds. If the determined voltage value is 96 V, it is equal to or greater than 94 V, which is a value obtained by subtracting a predetermined value at the time of heating from a reference value at the time of heating. Thereafter, the energization is continued until the temperature sensor 4 detects the boiling point.

Then, the control means 7 continuously determines the latest commercial AC power supply voltage by the power supply monitor 9 about every 0.2 seconds. Thereafter, if the commercial AC power supply voltage value determined by the power supply monitor 9 drops to 92 V, the control means 7 determines that the heating means 5 has a value less than 94 V, which is obtained by subtracting a predetermined value at the time of heating from a reference value at the time of heating. Stop energization and wait.

This operation assumes that another high-output device using the same power supply breaker as the electric water heater has started operation. For example, in the early morning or the like, the timer time of the electric water heater has come and water heating has started. Later, when the rice cooker's timer time comes later, rice cooking is started, or when warming of food is started in a microwave while boiling water, or the like.

Normally, the current capacity of a household power breaker is often 20 A, and a device with a standby power of several W class is
If a W class rice cooker and a 1000 W class electric kettle are used at the same time, the power breaker is shut off.
For this reason, the power supply breaker cutoff prevention function according to the present embodiment prevents the power supply breaker from being cut off by giving priority to the operation of other devices.

In this embodiment, when the power breaker cut-off prevention function is activated and the power supply to the heating means 5 is stopped, the voltage of the commercial AC power supply by the power supply monitor 9 naturally has no voltage drop by the electric water heater. The voltage which has dropped to 96V rises. The control means 7 does not automatically restart energization of the heating means 5 even if the commercial AC power supply voltage value by the power supply monitor 9 does not fall below the heating reference value by a predetermined value or more during heating while the power breaker cutoff prevention function is operating. I have to. Then, for example, if the user confirms that the rice cooker has finished cooking rice and has switched to heat retention, by pressing the reboil switch of the operation means 8,
The control means 7 causes the heating control means 6 to re-energize the main heater and the auxiliary heater of the heating means 5.
Thereafter, energization is continued until the boiling point is detected by the temperature sensor 4.

(Embodiment 2) The feature of this embodiment is that the control means 7 changes the commercial power supply voltage value from the power supply monitor 9 when the heating control means 6 is energizing the heating means 5. Is stored as a reference value at the time of heating.

As in the first embodiment, a value corresponding to 98 V as a reference value during heating and 4 V as a predetermined value during heating is given to the control means 7 in advance. Then, when the user puts water into the container 2 and turns on the power, the control means 7 causes the heating control means 6 to start energizing the main heater and the auxiliary heater of the heating means 5. Then, the commercial AC power supply voltage is determined by the power supply monitor 9 in about 0.2 seconds. If the determined voltage value is 96 V, it is equal to or greater than 94 V, which is a value obtained by subtracting a predetermined value at the time of heating from a reference value at the time of heating. Thereafter, about 0.
While the latest commercial AC power supply voltage is determined by the power supply monitor 9 every two seconds, energization is continued until the temperature sensor 4 detects the boiling point. When the boiling point is detected, the control means 7
Turns off the main heater and the auxiliary heater of the heating means 5 by the heating control means 6 for 3 minutes. After that, if the minimum value of the commercial AC power supply voltage value determined by the power supply monitor 9 during the heating up to the detection of the boiling point is still 96 V, the control means 7 performs the heating operation during the three minutes. The reference value is replaced from 98 V to 96 V and stored as a new heating reference value.

This is because when the electric water heater completes the process of boiling detection without interruption of the power supply, the lowest value of the commercial power supply voltage during heating measured during the heating operation is effective as a new heating reference value. Is determined. Thereafter, the next water heating is performed with the new heating reference value. In this case, if boiling cannot be detected despite the start of the heating operation, it is assumed that the power supply has been interrupted halfway, and the lowest value of the commercial power supply voltage determined by the power supply monitor 9 during heating is determined during heating. It is invalid as a reference value and is not stored.

Thus, the length of the indoor wiring from the power breaker to the outlet for the equipment and the thickness of the wiring, or the heating of the electric water heater adapted to different conditions at home such as other equipment using the power supply. The power supply voltage at the time can be grasped.

If the control means 7 has a non-volatile memory or the like, the latest heating reference value is not lost even if the power is turned off when the electric water heater is moved.
There is the advantage that you can keep remembering.

(Embodiment 3) The feature of this embodiment is that the power supply to the heating means 5 is not stopped and the power supply is stopped when the power supply breaker cutoff prevention function is operated, but the output is reduced and the power supply is continued.

The control means 7 determines whether the commercial AC power supply voltage value determined by the power supply monitor 9 while the main heater and the auxiliary heater of the heating means 5 are energized by the heating control means 6 is changed from a heating reference value to a heating predetermined value. If it drops by more than the value,
The control means 7 stops energizing the high-power main heater of the heating means 5 and continues energizing only the low-output auxiliary heater. As a result, the output of the electric water heater becomes about 9
Since the power is reduced from 25 W to about 75 W, the possibility of simultaneous use with other high-power devices increases.

In the present embodiment, the output of the heating means 5 during the operation of the power supply breaker cutoff prevention function is as low as about 75 W, so that the hot water cannot be boiled during the water heating, but the temperature of the hot water can be gradually increased. Therefore, it is possible to shorten the time until boiling when the water is heated again.

In this embodiment, the energization by the auxiliary heater of the heating means 5 is continued. However, if the main heater has a variable output value by phase control or the like, the energization of the main heater is continued at a low output. Is also good. In this case, the same effect can be obtained in preventing the power supply breaker from being cut off.

(Embodiment 4) As shown in FIG. 5, the feature of this embodiment is that a predetermined heating value changing means is provided for the user to set the predetermined heating value to an arbitrary value. .

As in the first embodiment, a value corresponding to 98 V as a reference value during heating and 4 V as a predetermined value during heating is given to the control means 7 in advance.

Normally, the control means 7 performs water heating with this initial value. For example, when a high-power device is used at the same time as the electric water heater, the power breaker cut-off prevention function does not operate normally and the power breaker is cut off. In the case where the power breaker cut-off prevention function frequently operates even though the high-power device is not used at the same time as the electric water heater, the initial value of the predetermined value at the time of heating of the control means 7 is determined by the use location of the electric water heater. May not be suitable for the power environment of In this embodiment, the user operates the operating means 8.
By turning on the power to the electric water heater while simultaneously pressing the reboil switch and the timer setting switch, the predetermined heating value setting means 11 for changing the predetermined heating value can be used. Heating predetermined value setting means 11
When the mode shifts to the setting mode, when the timer setting switch of the operating means 8 is pressed, the predetermined value at the time of heating rises by one rank,
By pressing the reboil switch, the predetermined value during heating can be lowered by one rank.

For example, when the power breaker cut-off prevention function does not operate normally and the power breaker is cut off when a high-power device is used at the same time as the electric water heater, the predetermined value at the time of heating is set to be raised by one rank. Thereby, the predetermined value at the time of heating is changed from the initial value of 4V to 2V. Also,
If the power breaker cutoff prevention function frequently operates even when the high-power device is not used at the same time as the electric water heater, the predetermined value at the time of heating is set to be lowered by one rank. As a result, the predetermined value at the time of heating is 6 V from the initial value of 4 V
Is changed to Thereafter, the next water heating is performed with the new heating predetermined value.

[0036] Thus, the length and thickness of the indoor wiring from the power breaker to the outlet for the equipment, or the simultaneous use of high-output equipment adapted to different conditions in each home such as other equipment using the power supply. A predetermined value at the time of heating can be obtained in consideration of a decrease in the power supply voltage during use.

If the control means 7 has a nonvolatile memory or the like, it is possible to keep storing the changed heating predetermined value without losing the changed heating value even when the power is turned off when the electric water heater is moved. There are advantages that can be done.

A special setting switch may be provided to shift to the setting mode of the predetermined value at the time of heating, or the predetermined value at the time of heating may be set by using a display element such as a liquid crystal while looking at the numerals. Is also good.

Further, since the voltage value of one rank of the predetermined value at the time of heating matches the resolution of the AC effective value based on the detection threshold value of the power supply monitor 9, the resolution of the AC effective value based on the detection threshold value is set to 0. If the voltage is set to 0.5 V, the voltage value of one rank can be set in units of 0.5 V, and the accuracy of the function of preventing the power supply breaker from being cut off can be further improved.

[0040]

As is apparent from the above embodiment, according to the first aspect of the present invention, during the heating operation of the electric water heater, priority is given to the operation of other devices, thereby preventing interruption of the power supply breaker. Good electric water heater can be provided.

According to the second aspect of the present invention, the length and the thickness of the indoor wiring from the power supply breaker to the outlet for the equipment, or different conditions in each household such as other equipment using the power supply. The power supply voltage at the time of the heating operation of the electric water heater adapted to the above can be grasped, and the accurate power supply breaker cutoff prevention function can be obtained.

According to the third aspect of the present invention, since the hot water in the middle of boiling can be kept warm and the temperature of the hot water can be gradually increased, the hot water does not need to be cooled. Time can be shortened.

According to the invention described in claim 4, the length of the indoor wiring and the thickness of the wiring from the power supply breaker to the outlet for the equipment, or different conditions in each home such as other equipment using the power supply. In the above, the predetermined value at the time of heating can be set in consideration of the decrease in the power supply voltage due to the simultaneous use of the electric water heater and other high-power devices, and a more accurate power supply breaker cutoff prevention function can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of first, second and third embodiments of an electric water heater according to the present invention.

FIG. 2 is a circuit diagram showing a configuration of a power supply monitor in the electric water heater of the present invention.

FIG. 3 is a diagram showing a waveform of a power supply monitor in the electric water heater of the present invention.

FIG. 4 is a diagram showing a comparison between a commercial power supply voltage value and a detection threshold value of a power supply monitor in the electric water heater of the present invention.

FIG. 5 is a block diagram showing a configuration of an electric water heater according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional electric water heater.

[Explanation of symbols]

 1 body 2 container 3 lid body 4 temperature sensor

Claims (4)

[Claims] 1. A heating means for heating a liquid in a container, a heating control means for supplying power to the heating means, and a power supply monitor for detecting a value of a commercial power supply voltage, wherein the control means comprises a heating control means When the voltage of the commercial power supply by the power supply monitor is reduced by a predetermined value at the time of the predetermined heating or more from the predetermined reference value at the time of power supply to the heating means by the power supply monitor, the power supply to the heating means by the heating control means is stopped. Electric water heater to control. 2. The electric water heater according to claim 1, wherein the control means stores the commercial power supply voltage value by the power supply monitor when the heating means is energized by the heating control means as a new heating reference value. 3. The control means, when energizing the heating means by the heating control means, adjusts a commercial power supply voltage value by a power supply monitor.
The electric water heater according to claim 1 or 2, wherein when the temperature is reduced by a predetermined value at the time of heating from the reference value at the time of heating, the heating control means conducts electricity so as to reduce the output of the heating means. 4. The electric water heater according to claim 1, further comprising a predetermined heating value setting means capable of setting the predetermined heating value to an arbitrary value.