JP3473225B2 - 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 retaining the water contained in a container.

[0002]

2. Description of the Related Art A conventional electric water heater is described below.
A description will be given based on FIGS. 4 to 6. FIG. 4 is a cross-sectional configuration diagram of essential parts of a conventional electric water heater, FIG. 5 is an explanatory diagram of boiling detection, and FIG. 6 is a circuit configuration diagram.

In FIG. 4, 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 provided on an upper part of the container 2. Further, a heater 4 for heating the water inside the container 2, a heater 5 for keeping the temperature and a temperature sensor 6 for detecting the water temperature are arranged at the bottom of the container, and the heating heater 4 is energized and controlled by the heating energizing means 8. The signal from the temperature sensor 6 is input to the temperature detecting means 7 to detect the water temperature. The boiling detecting means 9 is the temperature detecting means 7.
When it is detected that the water has boiled based on the temperature information from, a signal is output to the control means 10. The control means 10 enters the boiling mode when the water temperature is low, and energizes the heater 4 to raise the water temperature. When the water temperature rises and the boiling detecting means 9 detects boiling, the control means 10 notifies the boiling by the notifying means 11 and simultaneously shifts to the heat retention mode. In the heat retention mode, the signal from the temperature sensor 6 is converted into temperature information by the temperature detection means 7, and when the temperature is below a predetermined heat retention temperature, the control means 10 causes the heat retention energization means 12 to control the heat retention heater 5 (about 75).
w) is energized to heat the water, and when the temperature is equal to or higher than the predetermined heat retention temperature, the power supply to the heat retention heater 5 is stopped. When re-boiling is set by the re-boiling setting means 13, the control means 10 enters the boiling mode and water can be boiled again.

The boiling detection method of the boiling detection means 9 will be described with reference to FIG. In FIG. 5, the temperature of the temperature sensor rises at a substantially constant rate until it approaches the boiling point, and the temperature rise rate decreases when it approaches the boiling point. The time per unit temperature rise Δθ when the temperature rises at a constant rate is ΔT1, ΔT2, Δ
When T3 is set and ΔTn is a time per unit temperature increase Δθ near the boiling point, the case where the following equation is satisfied is detected as boiling water.

ΔT1 + ΔT2 + ΔT3 <ΔTn The entire operation of the electric water heater constructed as described above will be described with reference to FIG. The resistance value of the temperature sensor 6 attached to the container 2 under pressure changes according to the temperature change of the water in the container 2. Then, the resistance value ratio between the temperature sensor 6 and the resistor 7a connected in series changes, and A / D
The voltage change is input to the converter 7b, and the A / D converter 7
After being converted into a digital value by b, the microcomputer 20
Input as temperature information. The voltage determined by the resistors 7c and 7d is also input to the A / D converter 7b to determine the heat retention temperature. When heating water in the boiling mode, the microcomputer 20 activates the relay contact 8b of the relay 8a to energize the heater 4. After the boiling detection, when the temperature of the water is lower than the heat retaining temperature after entering the heat retaining mode, the microcomputer 20 operates the thyristor 12a to energize the heat retaining heater 5. When the water temperature is higher than the heat retention temperature, the microcomputer 20 operates in the thyristor 12a.
Is turned off, and the power supply to the heat retention heater 5 is stopped.

A switch 13 as reboil setting means is input to the microcomputer 20,
The buzzer 11 as a notification means and the display means 14 are output. When the switch 13 is pushed, the boiling mode is entered, and when the boiling is detected in the boiling mode, the buzzer 11 gives an alarm. The display means 14 has a boiling LED 14a and a heat retaining LED 14b. The boiling LED 14a is lit in the boiling mode and the heat retaining LED 14b is lit in the heat retaining mode.

[0007]

In the electric water heater having the above-mentioned conventional structure, the electric power of the heat-retaining heater is as small as 75w, and since the installation space is structurally limited, the heater wire is required to secure a resistance value. I had to reduce the cross-sectional area. Therefore, the heater is easily broken, and
It was hard to make. However, if the electric power of the heat retention heater is increased to solve the problem, there is a problem that the boiling water noise is increased.

In order to solve the above conventional problems, the present invention provides
A first object of the invention is to provide an electric water heater which raises the electric power of the warming heater to increase the cross-sectional area of the heater to prevent breakage of the heater, while minimizing the boiling noise at the time of keeping warm. A second object is, in addition to the achievement of the first object, to prevent the flicker of the lighting which occurs when the electric water heater and the lighting equipment of the present invention are connected to the same power supply circuit.

[0009]

In the electric water heater according to the present invention, at the time of heat retention, intermittent heating is performed by repeating energization and non-energization in which only a half wave of an AC power source is passed through the heater. As a result of increasing the cross-sectional area of the heater wire to prevent it and performing intermittent energization even if the power capacity of the heater is large, the actual power will be reduced, the boiling noise will be reduced, and there will be no breakage A heater is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is to heat a container for containing a liquid and water in the container.
A heating heater, a heat retaining heater for retaining the temperature of the liquid in the container, a temperature detecting means for detecting the temperature of the liquid in the container, and a predetermined temperature for retaining the temperature when the temperature is kept below a predetermined temperature. , an electric water heater having a heat insulating intermittent energization means for heat retaining heat conducted intermittently energized to repeat the energization and deenergization of only a half-wave of the AC power to the heat retaining heater,
By energizing only the half wave of the AC power supply warmth heater during incubation, with decreasing the power during thermal insulation power, exchange
Discontinuous energization that repeats energization and de-energization of only half wave of the current source
By doing so, it is possible to further reduce the electric power at the time of heat retention energization, so that the electric power of the heat insulation heater can be increased to increase the cross-sectional area of the heater wire and the disconnection of the heat insulation heater can be improved . Also, even if the power capacity is increased, the power when energized is reversed.
To reduce the boiling noise and keep the heater warm.
It is possible to eliminate the wire breakage and it is easy to make.

[0011] According to a second aspect of the invention, heat insulation intermittent energization means is an electric water heater according to claim 1, wherein the several seconds or longer periods of intermittent energization, also the power supply and the same power of the electric water heater of the present invention When a lighting device such as a fluorescent lamp is connected, the lighting may become dark only when the electric water heater is warmed and when the warming heater is energized. When the heat-retaining heater is not energized, the lighting is bright and dark repeatedly, which makes humans feel uncomfortable. Therefore, it is possible to make the cycle of intermittent energization several seconds or more by human-controlled intermittent energizing means such as microcomputer control so that human eyes do not feel the brightness of the illumination.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In FIGS. 1 and 2, the same parts as those in FIGS. 4 and 6 described above are designated by the same reference numerals, and a partial description thereof will be omitted.

[0013]

[Embodiment] (Embodiment 1) An embodiment relating to the invention described in claim 1 will be described as Embodiment 1 with reference to FIG.

The electric capacity of the heat retaining heater of the conventional electric water heater is usually 75 w. The electric capacity of the heat insulation heater 5 of Example 1 of the present invention is 150 w, but since the half-wave of the household AC power source is passed, the heat generation amount is 75 w, which is the same as the conventional electric water heater. At the time of heat retention, the boiling water noise from the heat retention heater has a correlation with the amount of heat generated per unit time, but both are the same and small. The cross-sectional area of the heater used for the warming heater 5 is twice as large as that of the conventional one, and the boiling water noise can be reduced to improve the disconnection of the warming heater 5.

(Embodiment 2) An embodiment relating to the invention described in claim 2 will be described as a second embodiment and will be described with reference to FIGS. 1 to 3.

In FIG. 1, when the heat retention / intermittent energization means 15 enters the heat retention mode, the temperature detection means 7 converts the temperature information into a temperature information by a signal from the temperature sensor 6, and if the temperature is below the heat retention temperature, the heat retention heater 5 (in this embodiment). Then, the water is heated by repeating energization and de-energization of only a half wave to 300 w), and if the temperature is equal to or higher than the heat retention temperature, the power supply to the heat retention heater 5 is stopped.

FIG. 2 shows the circuit configuration of the electric water heater according to the second embodiment.

In FIG. 2, the microcomputer 21
The gate circuit 15b is connected to the output of the thyristor, and the gate circuit 15b controls the thyristor 15a to energize the heat retention heater 5. When the temperature information from the temperature sensor 6 becomes equal to or lower than the heat retention temperature determined by the resistors 7c and 7d during heat retention, the microcomputer 21 controls the thyristor 15a through the gate circuit 15b to turn on only half-wave of the power to the heat retention heater 5. It is carried out only for a predetermined time of 1, and when the first predetermined time has elapsed, energization is stopped for a second predetermined time. This is repeated to heat the water. When the temperature information from the temperature sensor 6 becomes equal to or higher than the heat retention temperature determined by the resistors 7c and 7d, the power supply to the heat retention heater 5 is stopped at all.

FIG. 3 is a flow chart showing the operation of the electric water heater of the second embodiment. The operation flow of the microcomputer 21 at the time of heat retention will be described based on FIG.

In FIG. 3, first, at step 100, the power source is energized, and at step 101, the water temperature is checked. If the water temperature is high, shift to heat retention mode. When the water temperature is low (about 85 ℃
The following) turns on the boiling LED 14a in step 102, turns on the relay 8a, and energizes the heater 4.
In step 103, it waits until it boils, and when it boils, in step 104, the boiling LED 14a is turned off, the buzzer 11 gives a notification, the relay 8a is turned off, the energization to the heater 4 is stopped, and the heat retention mode is entered. In the heat retention mode, the heat retention LED 14b is turned on in step 105, and step 1
At 06, it is checked whether the temperature is higher than the heat retention temperature. If it is above, in step 107, the thyristor 15a is turned off to stop the power supply to the heat retention heater 5. In the following case, the thyristor 15a is turned on in step 108 to energize the heat retention heater 5. In step 109, the process waits until the first predetermined time (4 seconds in the second embodiment) has elapsed. When the first predetermined time has elapsed, in step 110, the thyristor 15a is turned off to stop energizing the heat retention heater 5. Then, in step 111, it waits for the second predetermined time (12 seconds in the second embodiment) to elapse. Second
When a predetermined time of is elapsed, the process proceeds to step 106.

As described above, in the second embodiment, the 300 watt warming heater 5 is used. However, at the time of keeping warm, only half wave of the AC power source is energized, and 12 seconds of non-energization is inserted for 4 seconds of energization. The actual electric power at that time is 37.5 w, which is half the 75 w of the warming heater 5 of the conventional electric water heater, and therefore the boiling water noise is much quieter than that of the conventional electric water heater. Further, if the cross-sectional area of the heater wire is the same length, it becomes four times as large, so that disconnection of the heat retention heater 5 can be eliminated, and the manufacturing becomes easy. Therefore, it is possible to eliminate the disconnection of the heat retention heater while quieting the boiling water noise.

(Embodiment 3) An embodiment relating to the invention described in claim 3 will be described as Embodiment 3 with reference to FIG.

The microcomputer 21 at the time of heat retention in FIG.
In the operation flow of Example 2, in the case of the second embodiment, the thyristor 15a is turned on at step 108 and only half a wave of the AC power is supplied to the heat insulation heater 5, and after the energization time of step 109 is 4 seconds, it is turned off at step 110. Turn on the power 1
The heat-retaining heater 5 was intermittently energized in 16 seconds for one cycle of 11 seconds and 12 seconds, but there was no discomfort due to flicker that the lighting equipment connected to the same power source as the electric water heater repeated bright and dark.

Generally, when the ON / OFF cycle is short, there is an unpleasant sensation due to flicker. Therefore, in the third embodiment, the microcomputer 21 causes the step 108 to 109 of FIG. Was energized, and the steps 110 to 111 were controlled for 4 seconds per cycle with no energization for 3 seconds. By shortening the cycle, the heat retention temperature can be controlled finely.

On the other hand, in the lighting equipment connected to the same power source, almost no discomfort due to the flickering of light and dark due to the on / off of the heat retention heater 5 was observed. It is desirable that the cycle is long if only the flicker of light and dark due to the on / off of the heat retention heater 5 to the lighting equipment connected to the same power source is captured, but there is practically no problem if the cycle is several seconds or more.

[0026]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, when the temperature of the electric water heater is kept warm, the warming heater is energized intermittently by repeating energization of only a half wave of the AC power source and non-energization to reduce the electric power at the time of warming energization. Therefore, it is possible to increase the electric power capacity of the warming heater to increase the cross-sectional area of the heater wire, reduce the boiling noise, maintain a predetermined temperature, and prevent the heater from breaking.

[Brief description of drawings]

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

FIG. 2 (a) is a circuit configuration diagram of the electric water heater. (B) is an explanatory view of the energization waveform of the heat retention heater

FIG. 3 is a flowchart showing the operation of the electric water heater.

FIG. 4 is a cross-sectional configuration diagram of essential parts of a conventional electric water heater.

FIG. 5 is a graph showing a boiling operation of the electric water heater.

FIG. 6 is a circuit configuration diagram of the electric water heater.

[Explanation of symbols]

2 containers 4 heating heater 5 Heat insulation heater 6 Temperature sensor 7 Temperature detection means 8 Heating energizing means 8a relay 9 Boiling detection means 10 Control means 15 Thermal insulation intermittent energizing means 15a thyristor 21 Microcomputer

Claims (2)

(57) [Claims] 1. A container for containing a liquid and the inside of the container
A heating heater for heating the water, a warming heater for warming the liquid in the container, a temperature detecting means for detecting the temperature of the liquid in the container, and a predetermined warming temperature or less for keeping warm at a predetermined warming temperature during warming when it is, the row intermittent energization to repeat the energization and deenergization of only a half-wave of the AC power supply to the heat retaining heater
Electric kettle equipped with a thermal insulation intermittent energization means for heat retaining heat are. 2. A heat insulating intermittently energizing means, according to claim 1, wherein the electric kettle was several seconds or more the period of the intermittent energization.