JPH08112201A - Electric water heater - Google Patents

Abstract

PURPOSE: To improve the operability of an electric water heater by automatically starting to heat upon the detection of the supply of water after detecting low-water. CONSTITUTION: A device comprises temperature detecting means 3 for detecting the temperature of a liquid in a container 1, heating means 2 for heating the liquid in the container 1, energizing means 4 for supplying electricity to the heating means 2, drive means 5 for driving the energizing means 4, and measuring means 7 for measuring the time required for a predetermined temperature increase. The device further comprises stopping means 6 continuously stopping the driving of the energizing means 4 if the time measured by the measuring means 7 is less than a predetermined value, and control means 8 for discontinuing the stopping of the energizing means 4 by the stopping means 6 upon detection of a temperature decrease to a predetermined temperature within a first predetermined time following the start of the stopping by the stopping means 6.

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 temperature of a liquid contained in a container.

[0002]

2. Description of the Related Art Heretofore, an electric water heater of this type has generally been constructed as shown in JP-A-5-285044. The configuration will be described below with reference to FIG.

As shown in FIG. 5, a heating means 2 for heating a liquid in the container 1 is brought into contact with a container 1 having a bottomed cylindrical shape, and a temperature-sensitive element 3a brought into contact with the container 1 and its output. Temperature detecting means 3 including an AD converter 3b for converting the electric signal into an electric signal
Detects the temperature inside the container 1. When the temperature detecting means 3 detects a temperature equal to or lower than a predetermined boundary temperature, the driving means 5 is driven and the energizing means 4 is energized to start heating the heating means 2. When the heating means 2 starts heating, the measuring means 7 calculates the rate of change of the liquid temperature in the container 1 based on the output of the temperature detecting means 3, and compares the output with the stopping means 6, and the temperature change rate has a predetermined value. If it becomes larger, it will be judged as blank baking,
The driving of the energizing means 4 is kept stopped until the user reheats it by the heating starting means or turns off the power once and resets.

[0004]

However, in the conventional structure as described above, there is no means for automatically canceling the stop of the energizing means 4 when the driving of the energizing means 4 is stopped once it is determined that the firing is performed. Therefore, even if the user performs air baking and notices water supply, the user can reheat with the heating start means,
It was inconvenient because heating could not be started unless the power was turned off and reset.

The present invention is intended to solve the above-mentioned problems.
The purpose of (1) is to start heating automatically when it is detected that water has been supplied within a first predetermined time after detection and the temperature has dropped to a predetermined temperature, even if air-baking is detected once.

A second object is to automatically start heating after the second predetermined time has elapsed even when water is supplied after the first predetermined time.

A third object is to notify the user of the water supply by means of a display when the grilling is detected, and to inform the user what to do when the grilling is done.

A fourth object is to provide a convenient electric water heater which blinks the display within the first predetermined time to inform that the time is within the first predetermined time. .

[0009]

In order to achieve the above first object, the present invention provides a container for containing a liquid, a temperature detecting means for detecting the temperature of the liquid in the container, and a liquid for heating the liquid in the container. Heating means, an energizing means for energizing the heating means, a driving means for driving the energizing means, a measuring means for measuring a predetermined temperature rise time, and a time measured by the measuring means is less than a predetermined value In this case, the temperature detecting means detects that the driving means continues to stop driving the energizing means, and that the temperature detecting means lowers the temperature to a predetermined temperature within a first predetermined time after the stopping means starts the stopping of the energizing means. Then, the control means for releasing the driving of the stopping means is provided.

In order to achieve the second object, the present invention is provided with a control means for releasing the driving of the stopping means when a second predetermined time elapses after the stopping means starts stopping the energizing means. is there.

Further, in order to achieve the third object, the present invention is provided with an indicator for informing the water supply when the stopping means starts to stop the energizing means.

Further, in order to achieve the fourth object, the present invention is such that the indicator blinks within a first predetermined time after the stopping means starts stopping the energizing means.

[0013]

According to the present invention, in the above-described structure, even if the air-baking is detected once, it is automatically heated when it is detected that the water has been supplied and the temperature has dropped to the predetermined temperature within the first predetermined time after the detection of the air-baking. Can start.

Even when water is supplied after the first predetermined time, heating can be automatically started after the second predetermined time has elapsed.

Further, at the time of detecting the air-burning, the user is informed of the water supply by the display to inform the user of the countermeasure at the time of the air-burning, and by blinking the display within the first predetermined time, the first predetermined time is reached. Can be notified.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric water heater according to an embodiment of the present invention will be described below with reference to FIGS. The same numbers are used for the same components as those described in the conventional example.

FIG. 1 is a block diagram of an electric water heater according to an embodiment of the present invention. 1 is a container for containing a liquid, 2 is a heating means for contacting the container to heat the liquid in the container, 3 is the container 1 The temperature detecting means 4 which is brought into contact with and detects the temperature of the liquid in the container is an energizing means for energizing the heating means 2.

Reference numeral 5 is a driving means, 6 is a stopping means, and 7 is a measuring means. When the temperature detecting means 3 detects a temperature below a predetermined boundary temperature (70 ° C. in this embodiment), the driving means 5 is The energizing means 4 is energized, and the measuring means 7 measures the time during which the temperature rises by a predetermined value when the temperature is below the boundary temperature (4 ° C. in this embodiment).

Reference numeral 8 is a control means for releasing the driving of the stopping means 6 when the temperature detecting means 3 determines that the temperature has dropped to a predetermined temperature or lower within a first predetermined time.

FIG. 2 shows the temperature characteristics of the temperature sensitive element when the electric water heater according to the embodiment of the present invention is fired.
In Fig. 1, the temperature of the temperature sensing element when the container 1 is heated without water and is detected at point A, and the temperature temporarily rises due to residual heat and then drops is shown by the solid line, and the temperature sensing when water is supplied at point B The element temperature is shown by a dotted line. θ1 is set to a predetermined temperature (70 ° C. in the embodiment), T2 is the time from when the temperature sensing element reaches the temperature sensing element temperature θ1, and T3 is when the temperature sensing element is used. Temperature sensor temperature is θ1
It is time to reach. Further, T1 is a first predetermined time in which T2> T1, and when it is detected that the temperature of the temperature sensing element has reached θ1 within T1 after the detection of baking, it is determined that water has been supplied, and the control means 8 stops the operation. The drive of the means 6 is released and the energization is restarted.

FIG. 3 is a circuit diagram of an electric water heater according to an embodiment of the present invention. In FIG. 3, 9 is an AC power supply.
The heating means 2 is composed of a first heating element 2a for heating the liquid in the container, and a second heating element 2b for heating and keeping the liquid in the container with less heating power than the first heating element 2a. It The energizing means 4 is a relay contact 4a, 4 connected in series with each heating element of the heating means 2 and an AC power source 9.
b, and relay coils 4c and 4d for controlling the relay contacts 4a and 4b.
A current is passed through d to close the relay contacts 4a and 4b. The temperature detecting means 3 is composed of a temperature sensitive element 3a for converting the temperature into a resistance value and an AD converter 3b for converting the divided voltage value of the temperature sensitive element 3a and the resistance into a binary code. Reference numeral 11 is a notifying means for notifying that the LED 11a or the buzzer 11b has detected the idle burning when the temperature rising time detected by the stopping means 6 is detected to be less than a predetermined value. Reference numeral 12 is an indicator such as an LED or LCD for notifying that there is no water in the container when the air-burning is detected. A microcomputer 10 (hereinafter abbreviated as a microcomputer) executes a program to realize a control method of the driving unit 5, the stopping unit 6, the measuring unit 7, and the control unit 8.

FIG. 4 is a portion for detecting whether or not the liquid in the container 1 should be heated by detecting the temperature after detecting the dry burning by the program stored in the microcomputer 10 of the present invention and driving the stopping means 6. The flowchart of FIG. 6 is shown, and the operation will be described below.

First, in step 1, it is determined whether or not a first predetermined time has elapsed. If the first predetermined time has not elapsed, in steps 2 and 3, the temperature detecting means 3 has lowered the temperature to a predetermined temperature. Determine whether or not. When the temperature is lower than the predetermined temperature, the stopping means 6 is executed by the control means 8 in step 5.
The drive of is released and energization is started. If the temperature is higher than the predetermined temperature, the process returns to step 1. When the first predetermined time has elapsed in step 1, the second predetermined time is waited in step 4, and after the elapse, the control means 8 stops the stop means 6 in step 5.
The drive of is released and energization is started.

[0024]

As described above, according to the present invention, even if the bakeout is detected once, it is automatically detected when it is detected that the water is supplied within the first predetermined time after the detection and the temperature is lowered to the predetermined temperature. The heating can be started.

Even when water is supplied after the first predetermined time, heating is automatically started after the second predetermined time has elapsed.

Further, when the air-baking is detected, the user is informed of the water supply by a display to inform the user what to do at the time of the air-baking, and within the first predetermined time, by blinking the display, the display is blinked within the first predetermined time. Let us know that there is something and improve usability.

[Brief description of drawings]

FIG. 1 is a block diagram of an electric water heater according to an embodiment of the present invention.

[FIG. 2] Similarly, temperature characteristics of the temperature-sensitive element when the electric water heater is boiled

FIG. 3 is a circuit diagram of the electric water heater

FIG. 4 is a flowchart showing the processing of the electric water heater.

FIG. 5 is a block diagram of a conventional electric water heater.

[Explanation of symbols]

 1 Container 2 Heating Means 3 Temperature Detecting Means 4 Energizing Means 5 Driving Means 6 Stopping Means 7 Measuring Means 8 Control Means 12 Indicators

Claims (4)

[Claims] 1. A container for containing a liquid, a temperature detecting means for detecting the temperature of the liquid in the container, a heating means for heating the liquid in the container, and an energizing means for energizing the heating means.
Drive means for driving the energizing means, measuring means for measuring a time for which a predetermined temperature rises, and stopping means for continuing the driving of the energizing means when the time measured by the measuring means is less than a predetermined value. And a control means for releasing the driving of the stopping means when the temperature detecting means detects that the temperature has dropped to a predetermined temperature within a first predetermined time after the stopping means starts to stop the energizing means. Electric water heater. 2. A second means after the stopping means starts stopping the energizing means.
2. The electric water heater according to claim 1, further comprising control means for releasing the driving of the stopping means when a predetermined time has passed. 3. The electric water heater according to claim 1, further comprising a display device which notifies water supply when the stopping means starts to stop the energizing means. 4. The first means after the stopping means starts to stop the energizing means.
The electric water heater according to claim 1, wherein the indicator is made to blink within a predetermined time period.