JPH0698826A - Electric water boiler - Google Patents

Abstract

PURPOSE:To lessen a temperature rise in a receptacle for preventing the receptacle and thermally sensitive element part from thermal deformation and discloration by stopping heating until liquid is poured into the receptzcle once the receptacle is heated while water is not in the receptacle and further start automatically the heating when the liquid is poured. CONSTITUTION:This electric water boiler is provided with a heating means 2 for heating liquid in a receptacle, a temperature detecting means 3 for detecting the temperature of the liquid in the receptacle, an electrifying means 4 for electrifying the heating means, a drive means 5 for driving the electrifying means 4 when the temperature in the receptacle reaches less than a boundary temperature, a measuring means 7 for measuring the temperature rise time and a stopping means 6 for stopping the electrifying means 4 when such time is less than a predetermined value. And once the stopping means 6 is driven, a control means 8 continues the drive of the stopping means 6 until it detects the temperature fall and stops the drive of the stopping means 6 when it detects the temperature fall to start automatically the heating when the temperature reaches less than the boundary temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to prevention of idle cooking of an electric water heater that heats and keeps the temperature of a liquid contained in a container.

[0002]

2. Description of the Related Art Conventionally, this type of electric water heater has a structure as shown in FIG.

That is, the heating means 2 for heating the liquid in the container is brought into contact with the bottomed cylindrical container, and the temperature-sensitive element 3a brought into contact with the container and the AD converter 3b for converting the output into an electric signal. The temperature detecting means 3 configured by detects the temperature inside the container. 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 temperature of the liquid in the container based on the output of the temperature detecting means 3, and compares the output with the stopping means 6 so that the temperature change rate has a predetermined value. If it becomes larger, the drive of the energizing means is simply stopped.

[0004]

However, since the temperature drop is not detected in such a conventional structure, it is possible to judge this even if water is injected once the firing is detected and the energizing means is turned off. However, it is inconvenient because the user cannot start the heating unless the user reheats it by the heating start means or resets the power by turning off the power once.

The present invention solves the above-mentioned problems, and is convenient for automatically starting heating when the liquid is injected and it is detected that the temperature is lower than the boundary temperature, even if heating is performed once to detect idle baking. The purpose is to provide an electric water heater.

[0006]

In order to solve the above problems, 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 heating device for heating the liquid in the container. Means, an energizing means for energizing the heating means,
Driving means for driving the energizing means when the temperature detecting means detects a temperature lower than a predetermined boundary temperature, measuring means for measuring a time for which a predetermined temperature rises when detecting a temperature lower than the boundary temperature, and time measured by the measuring means Is less than a predetermined value, stop means for continuing to drive the energizing means, and control means for stopping the driving of the stop means when the temperature detecting means detects a predetermined temperature decrease gradient are provided. .

[0007]

According to the present invention, by the above-mentioned solution means, even if the firing is detected, the heating can be automatically started when the liquid is injected and the temperature becomes lower than the boundary temperature.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram of an electric water heater showing an embodiment of the present invention, in which 1 is a container for containing a liquid, 2 is heating means for contacting the container to heat the liquid in the container, and 3 is the container. A temperature detecting means 4 for contacting 1 and detecting the temperature of the liquid in the container is an energizing means for energizing the heating means 2.

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 (90 ° 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 which measures the temperature decrease gradient by the output of the temperature detection means 3 and stops the drive of the stop means if this value is larger than a predetermined value (-3 ° C./6 seconds in this embodiment). It is what makes me.

FIG. 2 is a circuit diagram of an electric water heater showing an embodiment of the present invention. In the figure, 9 is an AC power supply. The heating means 2 is a first heating element for heating the liquid in the container.
2a and the second heating element 2b, which has a smaller heating power than the first heating element 2a and heats and keeps the temperature of the liquid in the container. The energizing means 4 includes relay contacts 4a and 4b connected in series with each heating element of the heating means 2 and the AC power source 9, and relay coils 4c and 4d for controlling the relay contacts 4a and 4b. The relay coil is configured so that current is passed through the relay coil to close the relay contact.

The temperature detecting means 3 comprises 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. ing.

Reference numeral 10 is an informing means for informing that there is no water in the container by the LED 10a or the buzzer 10b when the temperature rise time detected by the stopping means 6 is detected to be less than a predetermined value.

A microcomputer 11 (hereinafter abbreviated as a microcomputer) executes a program to drive the driving means 5, the stopping means 6, the measuring means 7, and the control means 8.
The control method of is realized.

FIG. 3 shows a flow chart of the portion for detecting the temperature by the program stored in the microcomputer according to the present invention to determine whether or not to heat the liquid in the container. The operation will be described below.

First, at step 21, it is judged whether or not a predetermined temperature drop is detected by the output of the temperature detecting means 3. If a temperature drop is detected here, step 22
Memorize that the temperature drop was detected in.

Next, in step 23, it is detected whether or not the temperature is equal to or lower than a predetermined boundary temperature. If the temperature is lower than the boundary temperature, if the temperature decrease is not detected in step 24, it is detected that the previous baking is detected. Judgment is made and heating is not performed, and the current mode is ended and the process ends. If the temperature drop is not detected in step 24, the energizing means 4 is driven in step 25. Next, in step 26, the time taken for the temperature to rise is measured,
The calculation process of the temperature rise gradient is performed. Next, in step 27, the temperature rise gradient value measured in step 26 is determined,
If the temperature rise gradient value is smaller than the predetermined value, this process is terminated in this state and the next boiling detection process is performed. If the temperature rise gradient value is equal to or greater than the predetermined value, the energizing means 4 is stopped in steps 28 to 30, the notifying means 11 is driven to notify the outside that the inside of the container is empty, and the drop detection flag is set. Then heating is completed.

The present invention can be easily realized with the above configuration.

[0020]

As described above, according to the present invention, it is possible to stop the heating means upon detection of an idle firing, and to easily drive the heating means automatically when a liquid is injected, which is convenient for use in electricity. A water heater can be provided.

[Brief description of drawings]

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

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

FIG. 3 is a flow chart showing a process in the electric water heater.
It is a chart.

FIG. 4 is a block diagram of a conventional example of the 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

Claims (1)

[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, an energizing means for energizing the heating means, and the temperature detecting means. When the means detects a temperature lower than a predetermined boundary temperature, the driving means drives the energizing means, when the temperature lower than the boundary temperature is detected, a measuring means for measuring a time for which a predetermined temperature rises, and a time measured by the measuring means is a predetermined time. An electric water heater provided with stop means for continuing to stop the drive of the energizing means when the value is less than a value, and control means for stopping the drive of the stop means when the temperature detecting means detects a predetermined temperature decrease gradient.