JPH05253080A - Electric water boiler - Google Patents

Abstract

PURPOSE:To avoid the lowering of preserving at all times. CONSTITUTION:Even when a warning heater 5 is energized at a predetermined rate by a warming heating means 9, temperature information from a temperature sensor 6 provided on the lower part of the vessel allows a temperature detecting means 7 to detect that the water temperature in the vessel 2 is low. When the detection output is sent from the temperature detecting means 7, a power increasing means 21 outputs a signal to a control means to raise the energizing rate of the warming heater 5.

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 water contained in a container.

[0002]

2. Description of the Related Art Recently, in an electric water heater,
It is generally used to keep water at a predetermined temperature after boiling water.

A conventional electric water heater will be described below. FIG. 6 is a partial cross-sectional configuration diagram of a conventional electric water heater. In FIG. 6, a container 2 having an upper surface opening is provided in the water heater body 1, and a lid 3 that covers the opening is arranged on the upper part of the container 2. Also, in the lower part of this container 2,
A heater 4 for heating the water inside the container 2, a heat retaining heater 5 for keeping the water warm, and a temperature sensor 6 for detecting the water temperature inside the container 2 are arranged.

A signal from the temperature sensor 6 is input to the temperature detecting means 7 to which the temperature sensor 6 is connected to detect the water temperature. A heating heater 4 is connected to the heating energizing means 8, and a warming heater 5 is connected to the warming energizing means 9. The heating heater 4 and the warming heater 5 are energized by the heating energizing means 8 and the warming energizing means 9, respectively. It The control means 10 connected to the temperature detecting means 7 is connected to the heating energizing means 8 and the warming energizing means 9, and the heater 4 and the warming heater are heated through the heating energizing means 8 and the warming energizing means 9 according to the temperature information from the temperature detecting means 7. 5 is energized to heat and keep the water in the container 2 warm.

FIG. 7 is a control circuit diagram of the electric water heater shown in FIG. In FIG. 7, a series circuit of a heating heater 4 for boiling and a relay contact 8a of a heating energizing means (relay) 8, a heater 5 for warming, and a warming energizing means (bidirectional thyristor) 9
Is connected in parallel between the power supplies. Output terminals of a microcomputer (hereinafter referred to as a microcomputer) 11 are connected to a relay coil 8b and a gate of a bidirectional thyristor 9, respectively, and control the relay contact 8a and the bidirectional thyristor 9 to heat the heater 4 and the heater 5 for keeping heat.
The amount of electricity supplied to

Further, the temperature sensor 6 which is pressure-attached to the container 1 is grounded through the resistor 7a, and when the temperature of the water in the container 1 rises, the resistance value of the temperature sensor 6 changes and the temperature sensor 6 The divided voltage of 6 and the resistor 7a also changes. 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 7
The divided voltage of a is converted into a digital value and input to the microcomputer 11. The connection point of the resistors 7c and 7d is connected to the A / D converter 7b, and the reference voltage is input to the A / D converter 7b. The above resistors 7a, 7c, 7d and A / D
The converter 7b constitutes the temperature detecting means 7.

With the above configuration, the operation 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 1 rises and boils by the heater 4. When the water is kept warm after boiling, the microcomputer 11 operates the thyristor 12 to energize the warm heater 5.

At this time, the resistance value of the temperature sensor 6 changes according to the temperature change of the water in the container 2, and the resistance value ratio between the temperature sensor 6 and the resistor 7a connected in series also changes to A /
The voltage change is input to the D converter 7b. And
After conversion to digital values by the A / D converter 7b, the microcomputer 11
Input as temperature information. Also, resistors 7c and 7d
The reference voltage determined by is also input to the A / D converter 7b, which determines the heat retention temperature. Further, when the temperature value input from the temperature sensor 6 is higher than the heat retaining 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 retaining 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 during the heat retention will be described with reference to FIG. If the water temperature is lower than the insulation temperature,
As shown in FIG. 8A, the microcomputer 11 synchronizes the gate of the bidirectional thyristor 9 with the commercial power source to change from "HI" to "L".
By setting to OW ", T1 and T2 of the bidirectional thyristor 9 are brought into a conductive state to continuously energize the heat retention heater 5 to raise the temperature of the water. Further, when the temperature of the water is higher than the heat retention temperature. As shown in FIG. 8B, the microcomputer 11 keeps the gate of the bidirectional thyristor 9 at "HI", so that T1 and T2 of the bidirectional thyristor 9 are
2 is brought into a non-conducting state to stop the energization of the heat retention heater 5.

[0010]

However, in the above-mentioned conventional configuration, the warm heater 5 is energized in the warm state when the ambient temperature where the electric water heater is placed is low and the power supply voltage is also low. However, there is a problem that the heat retention temperature of the water in the container 2 may decrease. Here, since the electric water heater only energizes or stops the warming heater 5 with constant power, if the power of the warming heater 5 is set too high, when water is boiled when the power supply voltage fluctuates high, etc. Emits a loud offensive sound.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an electric water heater in which the heat retention temperature of water in a container does not always decrease.

[0012]

In order to solve the above problems, an electric water heater according to the present invention comprises a heat retaining means for retaining the temperature of a liquid in a container, a heat retaining energizing means for energizing the heat retaining means, and the heat retaining energization. The control means for controlling the energization of the means, the temperature detection means for detecting the temperature of the liquid in the container, and the temperature detection means in the state where the heat retention means is energized. And a power increasing means for outputting to the control means so as to increase the amount of power supplied to the heat retaining means by a predetermined amount when the liquid temperature drops by a predetermined temperature.

Further, the electric water heater of the present invention comprises a heat retaining means for retaining the temperature of the liquid in the container, a heat retaining energizing means for energizing the heat retaining means, a control means for controlling energization of the heat retaining energizing means, In a state where the temperature detecting means for detecting the liquid temperature in the container and the heat retaining means for supplying electricity to the heat retaining means, when the liquid temperature detected by the temperature detecting means decreases, within a predetermined time. The electric power proportional increasing means for outputting to the control means so as to increase the amount of electric power supplied to the heat retaining means in proportion to the lowered temperature.

[0014]

With the above structure, when the temperature maintaining means is energizing the temperature maintaining means, when the temperature of the liquid detected by the temperature detecting means decreases by a predetermined temperature, the power increasing means energizes the temperature maintaining means. Since the power is output to the control means so as to increase it by a predetermined amount, the warming power is supplied only when the temperature of the liquid drops even when the warming heater is energized, such as when the room temperature where the electric water heater is placed is low in the warming state. Increase the power to the heat retention heater with high power,
The temperature of the water in the container will never drop from the heat retention temperature. Further, in a state in which the warming energizing means is energizing the warming means, the power proportional increasing means, when the liquid temperature detected by the temperature detecting means decreases, in proportion to the temperature decreased within a predetermined time, Since the electric power supplied to the heat retaining means is output to the control means so as to increase, the temperature of the water in the container does not always drop from the heat retaining temperature, and the predetermined heat retaining temperature is maintained with less electric power. ..

[0015]

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

FIG. 1 is a partial cross sectional view of an electric water heater showing a first embodiment of the present invention. In FIG. 1, the power increasing means 21 connected to the temperature detecting means 7 is connected to the control means 22 and even if the warming heater 5 is energized at the time of keeping warm while the warming energizing means 9 is energizing the warming heater 5. The temperature information from the temperature detecting means 7 outputs to the control means 22 to increase the energization ratio of the warming heater 5 when the temperature of the water is decreasing.

The circuit configuration diagram of the first embodiment is the same as that of FIG. 7 described above, but the operation content of the microcomputer 11 shown in FIG. 7 to the thyristor 9 is different. The outline of the operation will be described with reference to the timing chart of FIG. 2. By switching the gate of the thyristor 9 from “H1” to “LOW” in synchronization with the commercial power source, the T1 and T2 of the thyristor 9 are brought into a conducting state during the half wave. The heater 5 is energized, but when the gate of the thyristor 9 is not changed from "H1" to "LOW", it is in a non-conducting state during half a wave of the commercial power supply, and the heater 5 is not energized. To do. Therefore, by changing the conduction / non-conduction ratio (conduction ratio) of the thyristor 9, the conduction ratio of the heat retaining heater 5 changes, and the power of the heat retaining heater 5 changes.

With the above configuration, the operation will be described below with reference to FIG.
The operation flow chart of the microcomputer 11 will be described. First, in step S1, the heater 4 is energized, and step S
At 2 check if the water has boiled. If the water is not boiling, wait until it comes to a boil.
At 3, the power supply to the heater 4 is stopped. Then, in step S4, it is checked whether the temperature is equal to or higher than the heat retention temperature. If not higher than the heat retention temperature, step S5
Then, the heat retention heater 5 is energized at a predetermined ratio (about 60 W, energization ratio of about 6/8). Further, in step S6, the temperature .theta.1 is input from the temperature detecting means 7, and in step S7 it is checked whether the temperature is equal to or higher than the heat retention temperature.
At 8, the energization of the heat retention heater 5 is stopped and the process returns to step S4. If the temperature is not higher than the heat retention temperature in step S7, it is checked in step S9 whether the temperature has dropped to a predetermined temperature or lower than the heat retention temperature. If the temperature falls below the predetermined temperature, the ratio of the heat insulation heater 5 is increased in step S10 (energization ratio 7/8
After waiting for a predetermined time in step S11, step S11
Return to 6.

FIG. 4 is a partial cross-sectional configuration diagram of an electric water heater showing a second embodiment of the present invention, in which components having the same effects as those of the first embodiment are designated by the same reference numerals and their description is omitted. Is omitted. In FIG. 4, the electric power proportional increasing means 31 to which the temperature detecting means 7 is connected is connected to the control means 32, and the warming heater 5 is energized while the warming heater 5 is energized by the warming energizing means 9. Also, in accordance with the temperature information from the temperature detecting means 7, the control means 32 is caused to increase the amount of electric power supplied to the heat retention heater 5 in proportion to the temperature decreased within a predetermined time when the temperature of the water is decreased. Output.

The circuit configuration diagram of the second embodiment is similar to the circuit configuration diagram of the first embodiment described above, but the microcomputer 11
Is different from that of the first embodiment. With the above configuration, the operation will be described below with reference to the operation flowchart of the microcomputer 11 in FIG. First, the heater 4 is energized in step S21, and it is checked in step S22 whether the water has boiled. If the water has not boiled, wait until the water has boiled. When the water has boiled, the power supply to the heater 4 is stopped in step S23. Then, in step S24, it is checked whether the temperature is equal to or higher than the heat retention temperature. If it is equal to or higher than the heat retention temperature, wait until the temperature becomes lower than the heat retention temperature.
The heat insulation heater 5 is set to a predetermined ratio (about 60 W, energization ratio 6/8
Power). Further, the temperature θ1 is input from the temperature detecting means 7 in step S26, and after waiting for a predetermined time in step S27, the temperature θ1 is input again from the temperature detecting means 7 in step S28.
Enter 2. Then, in step S29, the temperature change rate per unit time is calculated from the two input temperatures, and in step S30, the amount of electric power corresponding to the temperature change rate is increased. Then, after waiting for a predetermined time in step S31, the temperature is input again from the temperature detecting means 7 in step S32. In step S33, it is checked whether the temperature is higher than the heat retention temperature,
If it is not higher than the heat retention temperature, the process returns to step S26. If it is higher than the heat retention temperature, the power supply to the heat retention heater 5 is stopped at step S34 and the process returns to step S24.

[0021]

As described above, according to the present invention, the warming power is increased when the water temperature does not rise even when the warming heater is energized, such as when the room temperature where the electric water heater is placed is low. Thus, the temperature of the water can be raised to a predetermined temperature and the heat retention can be maintained at the predetermined temperature.

[Brief description of drawings]

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

FIG. 2 is a timing chart for explaining the operation of the electric water heater of FIG. 1 during heat retention.

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

FIG. 4 is a partial cross-sectional configuration diagram of an electric water heater showing a second embodiment of the present invention.

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

FIG. 6 is a partial cross-sectional configuration diagram of a conventional electric water heater.

7 is a control circuit diagram of the electric water heater shown in FIG. 6;

8 is a timing chart for explaining the operation of the electric water heater of FIG. 6 during heat retention, where a is the case where the water in the electric water heater is lower than the heat retention temperature, and b is the case where the water in the electric water heater is higher than the heat retention temperature. Shows.

[Explanation of symbols]

 2 container 5 heat retention heater 6 temperature sensor 7 temperature detection means 7a, 7c, 7d resistor 7b A / D converter 9 heat retention energization means (bidirectional thyristor) 11 microcomputer 21 power increase means 22, 32 control means 31 power proportional increase means

Claims (2)

[Claims] 1. A heat retaining means for retaining the temperature of a liquid in a container, a heat retaining energizing means for energizing the heat retaining means, a control means for controlling energization of the heat retaining energizing means, and a temperature of the liquid in the container. When the temperature of the liquid detected by the temperature detecting means is lowered by a predetermined temperature in a state where the temperature detecting means and the heat retaining energizing means are energizing the heat retaining means, the amount of electric power supplied to the heat retaining means is changed. An electric water heater comprising: an electric power increasing means for outputting to the control means so as to increase a predetermined amount. 2. A heat retaining means for retaining the temperature of the liquid in the container, a heat retaining energizing means for energizing the heat retaining means, a control means for controlling energization of the heat retaining energizing means, and a temperature of the liquid in the container is detected. When the temperature of the liquid detected by the temperature detecting means is lowered in a state where the temperature detecting means and the heat retaining energizing means are energizing the heat retaining means, the temperature is proportional to the temperature lowered within a predetermined time. , An electric water heater comprising: a power proportional increasing means for outputting to the control means so as to increase the amount of electric power supplied to the heat retaining means.