JPS62129021A - Water amount detector of electric pot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a water volume detection bag ``placement'' for electric water heaters such as jar pots for boiling water and keeping it warm in ordinary households.

2. Description of the Related Art As shown in FIGS. 4 and 5, a conventional electric water heater of this type includes a cylindrical container 1 with a bottom, a heating element 2 for heating water contained in the container 1, and a heating element 2 for heating water contained in the container 1. , a first thermostat 3 attached to the bottom of the container 1 and connected in series with the heating element 2; and a first thermostat 3 attached near the heating element 20 and connected in series with the first thermostand 3. The second
a thermostat 4, an outer case 6 that covers the outer periphery of the container 1, and a lid 6 that covers the upper opening of the outer case 6;
It consisted of a water quantity display tube 7 communicating with the container 1 at the upper and lower portions and extending in the vertical direction. With this configuration, when there is water in the container 1, the temperature of the water is controlled by the first thermostat 3, while when there is no water in the container 1, the temperature of the water is controlled by the first thermostat 3, which is installed near the heating element 2. Generally, the thermostat 4 of 2 would stop supplying electricity to the heating element 2 when the temperature reached a high temperature. It has also been common to inform the user of the water level in the container 1 using the water level display tube 7. However, with this configuration, if the user turns on the water level display tube 7 without noticing that there is no water in the container 1, in order to detect that there is no water, the heating element 2 needs to be energized and the second It was necessary to reach a temperature at which the thermostat 4 would operate. Moreover, the second thermostand 4 was normally set at an operating temperature that would not operate when water was present, and the temperature was quite high. Furthermore, although the liquid level display tube 7id is usually a glass tube, the water is also transparent, making it difficult to see the water level display, and there is a strong need for improvement.

Problems to be Solved by the Invention However, with such a conventional configuration, if a user mistakenly turns on electricity without filling the container 1 with water, it takes time to detect that there is no water. There were problems in that the various parts became high temperature, causing the container 1 to change color, and the components of the heating element 2 and the like that were shattered to be highly heat resistant.

The present invention solves these problems and aims to provide an electric water heater that can detect the amount of water in the container.

Means for Solving the Problems In order to solve the above problems, the water amount detection device for an electric water heater of the present invention includes a cylindrical container with a bottom, communicating with the container,
It is constructed of a communicating tube extending in the vertical direction, two electrodes attached to the outer periphery of the communicating tube, and a capacitance detection means for detecting the capacitance of these two electrodes.

Function According to the above configuration, the amount of water in the container is detected by utilizing the fact that the capacitance between two electrodes attached to the outer periphery of the communicating tube changes depending on the amount of water in the communicating tube. It is something that can be done.

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

Figures 1a and 1) show parts diagrams of a water amount detection device for an electric water heater according to an embodiment of the present invention, and 8 is a container 1.
This is a communicating tube that communicates with the electrical insulator and extends in the vertical direction.This communicating tube 8 is made of glass or the like, and has two
Two sheets of electrode A9 and electrode B10 are attached.

FIG. 2 shows a circuit diagram of an electric water heater according to an embodiment of the present invention, and 11 is a microcomputer, and this microcomputer 11 includes a CPU, ROM,
It is a so-called one-chip microcomputer consisting of a RAM, a turnout port, etc. Reference numeral 12 denotes a DC power supply, and the electrode A9 and the electrode E10 are charged from this DC power supply 12 via a resistor 13. 14 is electrode A9 and electrode B1o
This transistor 14 is connected to the output port of the microcomputer 11 and turns ON/OFF upon receiving a signal. 15 is a comparator with an oven collector output, and electrode A
The output of the comparator 15 is connected to the input port of the microcomputer 11. Reference numeral 16 denotes an AC power supply, to which a series circuit of the heating element 2, the first thermostat 3, and the relay contact 17 is connected, and the microcomputer 1
The relay contact 17 is opened and closed by causing a current to flow through the relay coil 19 via the transistor 18 in response to a signal from the output port 1. 20 to 23 are LEDs, and these LEDs 20 to 23 are connected to the output port of the microcomputer 11, and are configured to light up in proportion to the amount of water.

Next, the operation of the electric water heater configured as described above will be explained.

FIG. 3 shows a flowchart of a program stored in the ROM in the microcomputer 11, and the operation of the program will be explained according to the procedure shown in this flowchart. First, in step 1, the time T1 is started to be measured, and in step 2, the transistor 14 is turned on and the electrode A9 is turned on.
discharge the charge, continue to discharge for 0.5 seconds in step 3, and then this. , if it exceeds 5 seconds, proceed to step 4. In step 4, the transistor 14 is ○FFI for a time T. starts measuring, waits until the output of the comparator 15 turns ON in step 5, and when the output turns ON, turns on the LEDs 20 to 23 corresponding to the time TK in step 6. Here, when water enters the communication pipe 8, the capacitance of the electrode A9 and the electrode 10 decreases □, and the capacitance of the electrode A9 and the electrode 10 decreases for a time T. becomes shorter. Then, in step 7, there is no water in the communication pipe 8,
When the time T0 becomes longer and the predetermined time T2 is reached, the relay contact 17 is turned OFF in step 8, and if it does not exceed T2, the relay contact 17' is turned ON in step 9.
Return to step 1.

Effects of the Invention As described above, according to the present invention, by utilizing the fact that the capacitance between two electrodes attached to the outer periphery of the communicating tube changes depending on the amount of water in the communicating tube, As a result, it can be used as a signal to indicate the amount of water or to stop energizing the heating element when the water runs out, making electricity the dog of utility value. It is possible to provide a water quantity detection device for a water heater.

[Brief explanation of drawings]

Figures 1a and 1b show a communicating pipe in a water flow detection device for an electric water heater according to an embodiment of the present invention; ai is a top view, b is a front view, and Figure 2 is a circuit of the electric water heater. 3 is a flowchart showing an example of a program for the electric water heater, and FIG. 4a is a flowchart showing an example of a program of the electric water heater. 5b is a front view and a side view showing a part of a conventional electric water heater in cross section, and FIG. 5 is an electric circuit diagram of the electric water heater. 1...Container, 8...Communication pipe, 9...
...Electrode A, 1°...Electrode B, 11...Microcomputer, 13...Resistor, 14...Transistor, 15. Ratio/articulator. Name of agent: Patent attorney Toshio Nakao and 1 other person8-
m Series of pipes 9-1 List A Figure 1 jO-''β Figure 3

Claims (1)

[Claims] A cylindrical container with a bottom, a communication tube communicating with the container and extending in the vertical direction, two electrodes attached to the outer periphery of the communication tube, and a capacitor for detecting the capacitance of these two electrodes. A water amount detection device for an electric water heater, comprising a detection means.