JP3192735B2 - Electric water heater - Google Patents

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 for heating and keeping water contained in a container.

[0002]

2. Description of the Related Art In recent years, in electric water heaters,
What keeps heat at a predetermined temperature after boiling water is generally used.

[0003] Hereinafter, a conventional electric water heater will be described. FIG. 11 is a partial cross-sectional configuration diagram of a conventional electric water heater. In FIG. 11, a container 2 having an upper surface opening is provided in a water heater main body 1, and a lid 3 for covering the opening is disposed above the container 2. In the lower part of the container 2,
A heater 4 for heating the water inside the container 2, a warming heater 5 for keeping the water warm, and a temperature sensor 6 for detecting the temperature of the water inside the container 2 are arranged.

[0004] A signal from the temperature sensor 6 is input to the temperature detecting means 7 to which the temperature sensor 6 is connected, and the temperature of the water is detected. The heating heater 4 is connected to the heating and energizing means 8, and the warming and heating means 5 is connected to the thermal insulation and energizing means 9. You. The control means 10 connected to the temperature detecting means 7 is connected to the heating and energizing means 8 and the heat retaining and energizing means 9. 5 is energized and the water in the container 2 is heated and kept warm.

FIG. 12 is a control circuit diagram of the electric water heater of FIG. In FIG. 10, a series circuit of a heater 4 for boiling and a relay contact 8a of a heating and energizing means (relay) 8, and a series circuit of a heater 5 for heat insulation and an energizing means (bidirectional thyristor) 9 are connected in parallel between power supplies. It is connected to the. Output terminals of a microcomputer (hereinafter referred to as a microcomputer) 11 are respectively connected to a relay coil 8b and a gate of a bidirectional thyristor 9, and control the relay contact 11a and the bidirectional thyristor 9 to control a heater 4 for boiling and a heater for heat retention. Heater 5
Is determined.

A temperature sensor 6 press-fitted to the container 2 is grounded via a resistor 7a. When the temperature of water in the container 2 rises, the resistance of the temperature sensor 6 changes, and the temperature sensor 6 6 and the divided voltage of the resistor 7a also change. The connection point between the temperature sensor 6 and the resistor 7a is connected to the A / D converter 7b, the A / D converter 7b is connected to the microcomputer 11, and the A / D converter 7b is connected to the temperature sensor 6 and the resistor 7a.
The divided voltage a is converted into a digital value and input to the microcomputer 11. The connection point between the resistors 7c and 7d is connected to the A / D converter 7b, and inputs the reference voltage to the A / D converter 7b. The above resistors 7a, 7c, 7d and A / D
The temperature detecting means 7 is constituted by the converter 7b.

The operation of the above configuration will be described below. First, when boiling water, the microcomputer 11 drives the relay coil 8b to energize the heater 4 via the relay contact 8a. Then, the temperature of the water in the container 2 rises by the heater 4 and boils. To keep the water warm after boiling, the microcomputer 11 activates the thyristor 9 to energize the warming heater 5.

At this time, the resistance value of the temperature sensor 6 changes due to a change in the temperature of the water in the container 2, and the ratio of the resistance value to the resistor 7a connected in series with the temperature sensor 6 also changes to A / A.
The voltage is input to the D converter 7b as the voltage change. And
After being converted to a digital value by the A / D converter 7b, the microcomputer 11
Is input as temperature information. Also, resistors 7c and 7d
Is also input to the A / D converter 7b to determine the heat retention temperature. Further, when the temperature value input from the temperature sensor 6 is higher than the heat retention temperature value determined by the resistors 7c and 7d, the microcomputer 11 does not operate the bidirectional thyristor 9 and does not energize the heat retention heater 5. . When the temperature value input from the temperature sensor 6 is lower than the heat retention temperature value determined by the resistors 7c and 7d, the microcomputer 11 operates the thyristor 9 to energize the heat retention heater 5 and Increase the temperature of the water.

The detailed operation at the time of keeping the temperature will be described with reference to FIG. If the temperature of the water is lower than the holding temperature,
As shown in FIG. 13A, the microcomputer 11 changes the gate of the bidirectional thyristor 9 from "HI" to "L" in synchronization with the commercial power supply.
OW ", T1 and T2 of the bidirectional thyristor 9 are turned on to continuously energize the heat retaining heater 5 to raise the temperature of the water. As shown in FIG. 13 (b), the microcomputer 11 maintains the gate of the bidirectional thyristor 9 at "HI", so that T1 and T1 of the bidirectional thyristor 9 are maintained.
2 is turned off, and the power supply to the heat retaining heater 5 is stopped.

[0010]

However, in the above-mentioned conventional configuration, the power supply voltage is increased if the power of the thermal insulation heater is too high because the thermal insulation heater 5 is merely energized or stopped at a constant power. When it does, it makes a harsh sound when the water boils. In the case where the resistance value of the warming heater is increased and the power of the warming heater is decreased, the temperature of the warming heater is reduced to 5 when the room temperature where the electric water heater is placed is low and the power supply voltage is low. However, there is a case where the water temperature in the container 2 does not rise even when the power is supplied to the power supply, and there is a problem that power efficiency is poor.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an electric water heater that can raise the water temperature to a predetermined heat retaining temperature with as little power as possible and keep the temperature near that temperature. It is.

[0012]

Means for Solving the Problems To solve the above-mentioned problems, an electric water heater according to the present invention comprises a heat retaining means for keeping a liquid in a container warm, an energizing means for supplying electricity to the heat retaining means,
And control means for performing control of energization of the energizing means, the said container
Room temperature detecting means for detecting an ambient temperature, and the room temperature detecting means
The output of the above means that even if the ambient temperature changes while
To the heat retaining means so as to keep the liquid temperature of the vessel at a predetermined value.
Output to the control means so as to change the amount of supplied power of
Power varying means. In addition, the present invention
Electric water heaters are a means of keeping the liquid in a container warm.
Energizing means for energizing the heat retaining means;
Control means for controlling the energization of the means;
Voltage detection means for detecting changes in the voltage of the commercial power supply that supplies power
Step, room temperature detecting means for detecting the ambient temperature of the container,
By the output of the voltage detecting means and the room temperature detecting means,
The liquid changes when the voltage of the commercial power supply or the ambient temperature changes.
Supply to the heat retaining means so as to keep the body temperature at a predetermined value
Electric power output to the control means so as to change the electric energy
Adjusting means .

[0013]

[0014]

[0015]

According to the above configuration, it is possible to use the electric water heater in the warm state.
Conventionally, when the room temperature where the heater is placed is low,
The water temperature did not rise even when the power was turned on.
By increasing the power, high power
Power is turned on, and the electric water heater is
To reduce heat retention when room temperature is high
Since the power supply to the heat retaining heater is performed with lower power, the predetermined heat retaining temperature is maintained with as little power as possible. Also,
At a higher power by increasing the heat insulating power when room temperature electric kettle is placed is <br/> rather low, or has become a commercial power source voltage is low deeds energization of the thermal insulation heater in thermal insulation state, also kept is room temperature electric kettle is placed is rather high, or the voltage of the commercial power supply is high in the state
Since the energization of the thermal insulation heater at a lower power by reducing the thermal insulation power when the predetermined retained temperature is maintained at as little power as possible.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. It is to be noted that components having the same functions and effects as those of the conventional example are denoted by the same reference numerals and description thereof is omitted.

FIG. 1 is a partial cross-sectional view of an electric water heater according to a first embodiment of the present invention. In FIG. 1, a voltage detecting means 21 detects a voltage change of a commercial power supply. The constant power means 22 connected to the voltage detecting means 21
To the control means 23 so as to change the energization ratio to the heat retaining heater 5 so that the amount of electric power supplied to the heat retaining heater 5 does not change even if the voltage of the commercial power supply changes according to the output of the voltage detecting means 21. I do.

FIG. 2 is a control circuit diagram of the electric water heater of FIG. In FIG. 2, a resistor 21a is provided at both ends of the commercial power supply.
21b and a diode 21c are connected in series. A connection point between one end of the commercial power supply and the resistor 21a is connected to the anode side of a diode 21f through a parallel circuit of a resistor 21d and a capacitor 21e. The input terminal of the D converter 24 is connected, and the cathode side of the diode 21f is connected to a resistor.
It is connected to the connection point 21a, 21b. The voltage detecting means 21 is configured as described above. Further, this A / D converter 24
Is connected to a microcomputer 25, and information from the voltage detecting means 21 is digitally converted by an A / D converter 24 and input to the microcomputer 25.

The operation of the above configuration will be described below. First, the commercial power supply is half-wave rectified by the diode 21c, and the voltage is divided by the resistors 21a and 21b. This divided voltage is smoothed by a resistor 21d and a capacitor 21e,
The constant voltage is A / D converted by the A / D converter 24 and input to the microcomputer 25 as a digital value. Thus, when the commercial power supply changes, the input voltage of the A / D converter 24 changes and the change is input to the microcomputer 25.

Here, in FIG. 3, similarly to FIG. 11, the gate of the thyristor 9 is changed from "HI" to "LOW" in synchronization with the commercial power supply, so that T1 and T1 of the thyristor 9 are changed.
2 is kept in a conductive state during the half-wave to energize the heat retaining heater 5. Change the gate of thyristor 9 from "HI"
If the power supply is not set to LOW, the power supply to the heat retaining heater 5 is stopped during the half-wave of the commercial power supply, and the power supply to the heat retaining heater 5 is stopped. The ratio changes and the heater 5
Power changes.

FIG. 4 is a flowchart showing the operation of the microcomputer 25 shown in FIG. First, in step S1, the heater 4
Is turned on, and it is checked in step S2 whether water has boiled. If the water is not boiling, the process waits until the water boils. When the water boils, the power supply to the heater 4 is stopped in step S3. In step S4, it is checked whether the temperature is equal to or higher than the heat retaining temperature. If the temperature is equal to or higher than the heat retaining temperature, the power supply to the heat retaining heater 5 is stopped in step S5, and the process returns to step S4. Step S
If the temperature is not equal to or higher than the heat retention temperature in step 4, the heat retention heater 5 is energized at a predetermined ratio (about 60 W, power supply rate about 6/8) in step S6.

Further, in step S7, a voltage change from the power supply voltage is input as an input voltage V1. Then, in step S8, the input voltage V1 is compared with a preset standard value V0. If the input voltage V1 is larger than the standard value V0, the input voltage V1 is proportional to the difference between the input voltage V1 and the standard value V0 in step S9. Thus, the energization ratio of the heat retaining heater 4 is reduced. If the input voltage V1 is smaller than the standard value V0 in step S8, the energization ratio of the heat retaining heater 4 is increased in step S10 in proportion to the difference between the input voltage V1 and the standard value V0. Then, after waiting for a predetermined time in step S11, the process returns to step S4.

FIG. 5 is a partial sectional configuration view of an electric water heater according to a second embodiment of the present invention. In FIG. 5, the room temperature detecting means 31 detects the room temperature where the container is placed.
The power variable means 32 to which the room temperature detecting means 31 is connected is connected to the control means 33. In order to prevent the room temperature from decreasing and the temperature of the liquid from being unable to be maintained at a predetermined value and becoming low, the room temperature detecting means 31 An output is output to the control means 33 so that the amount of electric power supplied to the heat retaining heater 5 is increased by the output.

FIG. 6 is a circuit diagram of the electric water heater of FIG. In FIG. 6, one end of the commercial power supply is a room temperature sensor 31a.
And a resistor 31b grounded through a series circuit, and a room temperature sensor
The resistance value of the room temperature sensor 31a changes according to the temperature change of the room temperature where the container 2 is placed.
The resistance value ratio of 31b also changes. Room temperature sensor 31a and resistor 31
The connection point b is connected to the input terminal of the A / D converter 34, and the voltage division ratio between the room temperature sensor 31a and the resistor 31b is input to the A / D converter 24 as a voltage change. Thus, the room temperature detecting means 31 is configured. Further, the A / D converter 34 is connected to the microcomputer 35, and the information from the room temperature detecting means 31 is transmitted to the A / D converter 34.
And is input to the microcomputer 35.

The operation of the above configuration will be described below. FIG. 7 is a flowchart showing the operation of the microcomputer 35 of the second embodiment. First, in step S21, the heater 4
Is turned on, and it is checked in step S22 whether water has boiled. If the water is not boiling, it waits until the water boils. If the water boils, the power supply to the heater 4 is stopped in step S23. Then, it is checked in step S24 whether the temperature is equal to or higher than the heat retention temperature. If the temperature is equal to or higher than the heat retention temperature, the power supply to the heat retention heater 5 is stopped in step S25, and the process returns to step S24.
If the temperature is not equal to or higher than the heat retention temperature in step S24, the heat retention heater 5 is energized at a predetermined ratio (approximately 60 W, power supply ratio approximately 6/8) in step S26.

Further, at step S27, the temperature θ1 is inputted from the room temperature detecting means 31. In step S28, the input temperature θ1 is compared with a predetermined temperature θ0. If the input temperature θ1 is lower than the predetermined temperature θ0, the energization ratio of the heat retaining heater 4 is increased by a certain value in step S29. When the input temperature .theta.1 is higher than the predetermined temperature .theta.0, the energization ratio of the heat retaining heater 4 is reduced by a certain value in step S30. Then, after waiting for a predetermined time in step S31, the process returns to step S24.

In the second embodiment, step S
Although the on / off ratio of the heat retaining heater 5 is raised or lowered by a certain value in 29 and S30, a plurality of on / off ratios may be provided according to the room temperature.
FIG. 8 is a partial cross-sectional configuration diagram of an electric water heater according to a third embodiment of the present invention. In FIG. 8, the voltage detecting means 41
Detects the change in the voltage of the commercial power supply,
Detects the room temperature at which the container is located. Power adjusting means to which the voltage detecting means 41 and the room temperature detecting means 42 are connected.
Reference numeral 43 is connected to the control means 44, and is controlled so that when the voltage of the commercial power supply changes according to the output of the voltage detection means 41, the power supply ratio to the heat retaining heater 5 is changed so that the amount of electric power supplied to the heat retaining heater 5 does not change. In order to prevent the temperature of the liquid from being reduced to a predetermined value when the temperature of the liquid drops extremely, the amount of electric power supplied to the heater 5 is determined by the output of the room temperature detecting means 42. It outputs to the control means 44 so as to raise it.

FIG. 9 is a circuit diagram of the electric kettle of FIG. In FIG. 9, resistors 41a and 41b are provided at both ends of a commercial power supply.
And a diode 41c are connected in series. A connection point between one end of the commercial power supply and the resistor 41a is connected to a resistor 41d and a capacitor.
Via the parallel circuit of 41e, it is connected to the anode side of the diode 41f and to one of the input terminals of the A / D converter 45, and the cathode side of the diode 41f is connected to the connection point of the resistors 41a and 41b. It is connected. The above constitutes the voltage detecting means 41.

A connection point between one end of the commercial power supply and the resistor 41a is grounded through a series circuit of a room temperature sensor 42a and a resistor 42b, and the room temperature sensor 42a is changed by a temperature change of the room temperature in which the container 2 is placed. The resistance value of the room temperature sensor 42a changes, and the resistance value ratio between the room temperature sensor 42a and the resistor 42b also changes. The connection point between the room temperature sensor 42a and the resistor 42b is connected to the other input terminal of the A / D converter 45, and the voltage division ratio between the room temperature sensor 42a and the resistor 42b is input to the A / D converter 45 as a voltage change. .
Thus, the room temperature detecting means 42 is configured. Further, the A / D converter 45 is connected to a microcomputer 46,
The information from the room temperature detecting means 41 and the room temperature detecting means 42 are digitally converted by the A / D converter 45 and input to the microcomputer 46.

The operation of the above configuration will be described below. First, the commercial power supply is half-wave rectified by the diode 41c, and the voltage is divided by the resistors 41a and 41b. This divided voltage is smoothed by a resistor 41d and a capacitor 41e,
The constant voltage is A / D converted by the A / D converter 45, and is input to the microcomputer 46 as a digital value. This allows
When the commercial power supply changes, the input voltage of the A / D converter 45 changes and the change is input to the microcomputer 46. Further, the resistance of the room temperature sensor 42a changes due to a change in the temperature of the room where the container 2 is placed, and the partial pressure ratio of the room temperature sensor 42a and the resistor 42b connected in series also changes to change the A / D converter. The voltage is input to the microcomputer 45 as a voltage change, converted into a digital value by the A / D converter 45, and input to the microcomputer 46 as room temperature information.

FIG. 10 is a flowchart showing the operation of the microcomputer 46 according to the third embodiment. First, the heater 4 is energized in step S41, and it is checked in step S42 whether water has boiled. If the water is not boiling, the process waits until the water boils. When the water boils, the power supply to the heater 4 is stopped in step S43. Then, it is checked in step S44 whether or not the temperature is equal to or higher than the heat retaining temperature.
Then, the power supply to the heat retaining heater 5 is stopped, and the process returns to step S44. If the temperature is not equal to or higher than the heat retaining temperature in step S44, the heat retaining heater 5 is energized at a predetermined ratio (approximately 60 W, power supply ratio approximately 6/8) in step S46.

Further, in step S47, a voltage change from the power supply voltage is input as an input voltage V1. Step S48
And the input voltage V1 and the preset standard value V
If the input voltage V1 is larger than the standard value V0, the energizing ratio of the heat retaining heater 4 is reduced in proportion to the difference between the input voltage V1 and the standard value V0 in step S49. If the input voltage V1 is smaller than the standard value V0, the energizing ratio of the heat retaining heater 4 is increased in step S50 in proportion to the difference between the input voltage V1 and the standard value V0.

Further, the temperature θ1 is inputted from the room temperature detecting means 42 in a step S51. In step S52, the input temperature θ1 is compared with a preset predetermined temperature θ0,
When the input temperature θ1 is lower than the predetermined temperature θ0, the energization ratio of the heat retaining heater 4 is increased by a predetermined value in step S53, and when the input temperature θ1 is higher than the predetermined temperature θ0, the process proceeds to step S53.
At 54, the energization ratio of the heat retaining heater 4 is reduced by a certain value. Then, after waiting for a predetermined time in step S55, the process returns to step S44.

[0034]

As described above, according to the present invention, when the room temperature where the electric water heater is placed is low, or when the voltage of the commercial power supply becomes extremely low, the heat retention power is increased to keep the heat at a high level. When the heater is energized, and when the temperature of the electric water heater is high or when the voltage of the commercial power supply becomes extremely high, the heat retention power is reduced and the heat retention heater is supplied with low power. It is possible to maintain a predetermined heat retaining temperature with as little power as possible.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional configuration diagram of an electric water heater according to a first embodiment of the present invention.

FIG. 2 is a control circuit diagram of the electric water heater of FIG.

FIG. 3 is a timing chart for explaining the operation of the electric water heater of FIG. 1 at the time of keeping the temperature.

FIG. 4 is a flowchart showing an operation of the microcomputer 25 of FIG. 2;

FIG. 5 is a partial cross-sectional configuration diagram of an electric water heater according to a second embodiment of the present invention.

FIG. 6 is a control circuit diagram of the electric water heater of FIG. 5;

FIG. 7 is a flowchart showing an operation of the microcomputer 35 of FIG.

FIG. 8 is a partial cross-sectional configuration diagram of an electric water heater according to a third embodiment of the present invention.

FIG. 9 is a control circuit diagram of the electric water heater of FIG. 8;

FIG. 10 is a flowchart showing an operation of the microcomputer 46 of FIG. 8;

FIG. 11 is a partial cross-sectional configuration diagram of a conventional electric water heater.

FIG. 12 is a control circuit diagram of the electric water heater in FIG. 11;

13 is a timing chart for explaining the operation of the electric water heater of FIG. 11 at the time of keeping the temperature.
Indicates a case where the water temperature is lower than the heat retention temperature, and b indicates a case where the water temperature is higher than the heat retention temperature.

[Explanation of symbols]

 2 Container 5 Insulation heater 6 Temperature sensor 7 Temperature detection means 7a, 7c, 7d Resistor 7b A / D converter 9 Insulation current supply means (bidirectional thyristor) 21, 41 Voltage detection means 21a, 21b, 21d, 41a, 41b , 41d Resistors 21c, 21f, 41c, 41f Diodes 21e, 41e Capacitors 22 Constant power means 23, 33, 44 Control means 24, 34, 45 A / D converters 25, 35, 46 Microcomputer 31, 42 Room temperature detecting means 31a , 42a Temperature sensor 32b, 42b Resistor 32 Power variable means 43 Power adjusting means

Claims (2)

(57) [Claims] 1. An insulating means for keeping a liquid in a container warm, an energizing means for energizing the insulating means, a control means for controlling energization of the energizing means, and detecting an ambient temperature of the container.
Room temperature detecting means, and the output of the room temperature detecting means,
Even if the ambient temperature changes while keeping the temperature, the liquid temperature of the
The amount of power supplied to the heat retaining means is maintained so as to keep the temperature at a predetermined value.
Power varying means for outputting to said control means to change
An electric kettle provided with: 2. A heat retaining means for keeping a liquid in a container warm, an energizing means for energizing the heat retaining means , a control means for controlling energization of the energizing means, and a power supply to the heat insulating means.
Voltage detecting means for detecting a change in voltage of a commercial power supply, a room temperature detecting means for detecting an ambient temperature of the container, and the voltage
The output of the sensing means and room temperature detecting means, said commercial power
Electricity and a power adjusting means for outputting a liquid temperature with respect to the voltage change and the change in the ambient temperature of the source to the control means to vary the amount of power supplied to said heat insulating means so as to kept at a predetermined value Water heater.