JPS62109520A - 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 the Invention The present invention relates to an electric water heater such as a jar pot for boiling water and keeping it warm in general households.

2. Description of the Related Art As shown in FIGS. 3 and 4, a conventional electric water heater of this type includes a cylindrical container 1 with a bottom, a heating element 2 that heats water and metal housed 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 thermostat 3. A second thermostat 4, an outer case 6 that covers the outer periphery of the container 1, and a lid and body C that covers the upper opening of the outer case 5. It consisted of a quantity display tube 7. 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. When the thermostat 4 of No. 2 reached a high temperature, the electricity to the heating element 2 was completely stopped. It has also been common to inform the user of the water level in the container 1 using the liquid level display tube 7. However, with this configuration, if the user does not notice through the liquid level display tube 7 that there is no water in the container 1 and energizes the heating element 2, it is necessary to energize the heating element 2 in order to detect that there is no water. It was necessary to reach a temperature at which the second thermostat 4 operates.

Moreover, since the second thermostat 4 is normally set at an operating temperature that does not operate when water is present, the temperature was quite high.

Problems to be Solved by the Invention However, with such a conventional configuration, if a user mistakenly energizes the heating element 2 without filling the container 1 with water, it takes a long time to detect that there is no water. As a result, various parts of the container 1 became discolored due to high temperatures 9, and the components of the heating element 2 were required to have high heat resistance.

The present invention is intended to solve all of these problems, and aims to provide an electric water heater that can detect the absence of water in the container and completely stop energizing the heating element. .

Means for Solving the Problems In order to solve all of the above problems, the electric water heater of the present invention has the following features:
A cylindrical container with a bottom, a heating element for heating the liquid contained in the container, a liquid volume display tube communicating with the container and having a float 1 inside and extending in the vertical direction, and the liquid volume. A light-receiving element is provided at a position facing the light-emitting element disposed outside the lower end of the display tube and outputs a signal depending on the presence or absence of liquid at the lower end, and the output of the light-receiving element is used to energize the heating element. It is constructed by a means for stopping energization completely.

Effect According to the above configuration, when there is no liquid in the container, the float in the liquid level display tube lowers, blocking the transmission of light from the light emitting element to the light receiving element, and immediately stops energizing the heating element. , it is possible to provide a safe and easy-to-use electric water heater with a simple configuration.Embodiment Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 shows an electric circuit diagram of an electric water heater according to an embodiment of the present invention, and FIG. 2 shows a partial sectional view of the same electric water heater. Components that are the same as those in FIG. 4 are given the same numbers, and their explanations will be omitted. In the figure, 8 is an AC power source, and to this AC power source 8 is connected a series circuit of a heating element 9 and a relay contact 10 that heats the liquid contained in the bottomed cylindrical container 1 shown in FIG. has been done. 11 is a thermistor attached to the bottom of container 1, 12 is a comparator with an oven collector output, and its input is the voltage divided by thermistor 11 and resistor RA, and the reference voltage divided by two resistors RB and R6. , and the output of the comparator 12 causes the transistor 1 to
3, the relay coil 14 is fully operated, and the relay contact 1
0iON-OFF. 16 is a light emitting element that emits infrared rays, 16 is a light receiving element that receives infrared rays, and this light receiving element 16
The light emitting element 16 is disposed so as to face the outer side of the lower end of the liquid level display tube 7, and a float 17 that floats on water inside the liquid level display tube lowers when the water runs out, causing the light emitting element 1 to float.
6 infrared rays are transmitted to the light receiving element 16.

On the other hand, when the light receiving element 16 receives infrared rays from the light emitting element 16, it turns on, and the output of the light receiving element 16 supplies a driving current to the base of the transistor 13 via a resistor. 18 is a DC power supply for operating the circuit described above.

The operation of the above configuration will be explained next.

First, when water is placed in the container 1 and electricity is applied to the heating element 9, the thermistor 11 is at a low temperature until the water boils, so the comparator 1
The output of light receiving element 16 becomes OFF, but the output of light emitting element 1 becomes OFF.
Transistor 13 turns on when it receives the infrared rays of 5.
is turned on, energizing the relay coil 14, and relay contact 10
iON. As a result, the heating element 9 is continuously energized and continues to heat the water in the container 1. When the water in the container 1 becomes high temperature, the output of the comparator 12 turns on, which turns off the transistor 13 and causes the relay coil 14 to turn off.
Since the power to the heating element 9 is cut off and the relay contact 10 is turned off, the power to the heating element 9 is also cut off to maintain a constant temperature. Furthermore, when there is little water in the container 1, the float 17 blocks the infrared rays from the light emitting element 16, so the light receiving element 16 is turned off, and as a result, the transistor 13 is turned off regardless of the output of the comparator 12. The power supply to the heating element 9 is stopped.

Effects of the Invention As described above, according to the present invention, when there is no liquid in the container, the float in the liquid level display tube lowers and blocks the transmission of light from the light-emitting element to the light-receiving element, and immediately reaches the heating element. Since the electricity is turned off, the container may be baked dry,
There is no possibility of deterioration, and as a result, a safe and easy-to-use electric water heater can be provided with a simple configuration.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram of an electric water heater showing an embodiment of the present invention, Fig. 2 is a partially cutaway front view of the electric water heater, and Fig. 3 is a partial and complete view of a conventional electric water heater. The side view shown in cross section, Figure 4, is an electrical circuit diagram of the electric water heater.
... Heating element, 10 ... Relay contact, 14
... Relay coil, 15 ... Light emitting element, 1θ ... Light receiving element, 17 ... Float. Name of agent: Patent attorney Toshio Nakao and one other person: Tokasa Shiro, N. Figure 4

Claims (1)

[Claims] A cylindrical container with a bottom, a heating element that heats the liquid contained in the container, a liquid volume display tube communicating with the container and having a float therein and extending in the vertical direction, and the liquid volume display. A light-receiving element is provided at a position opposite to a light-emitting element disposed outside the lower end of the tube and outputs a signal depending on the presence or absence of liquid at the lower end, and the output of the light-receiving element is used to energize the heating element. An electric water heater comprising a means for stopping energization.