JPH0255016A - Electrical pot - Google Patents

Abstract

PURPOSE:To surely boil water by allowing a control means to turn OFF a relay driving means for a certain time and then turn-ON said driving means if the temperature of a pot which is detected by a temperature sensor does not reach a prescribed temperature after the lapse of a prescribed time after the relay driving means is turned ON. CONSTITUTION:A time measuring means 11 measures the time from the time when a control means 10 outputs an ON-signal into a relay driving means 5, and if the temperature detected by temperature detecting means 6 does not reach a prescribed temperature (90 deg.C) after the lapse of a prescribed time (e.g., 10min.), the control means 10 outputs an OFF-signal into the relay driving means 5 for a certain time (e.g., 1sec.), and outputs an ON-signal. Since a condenser 8c is charged to a zenor voltage (30V) during the OFF in 1 sec., a relay contact point 3 is closed at the time print when the ON-signal is outputted, and a heating body 2 starts heating, and the water in a pot 1 is boiled. Therefore, the disposition of the case when the heating body 2 does not generate heat is permitted, keeping the relay contact point 3 in opened state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric water heater for heating and boiling water contained in a container.

2. Description of the Related Art Conventional electric water heaters have been constructed as shown in FIGS. 2 and 3. In FIGS. 2 and 3, 1 is a container containing water, 2 is a heating element that heats the water in the container 1, 3 is a relay contact that controls energization of the heating element,
4 is a relay coil that opens and closes the relay contact 3, 6 is a relay drive means that controls energization of V4 (relay coil),
It is composed of a transistor 5IL and resistors sb and 6c. 6 is a temperature detection means for detecting the temperature of the container 1;

It is composed of a thermistor 6a and a temperature measurement circuit 6b. 7 is a relay driving means 6 if the temperature detected by the temperature detecting means 6 is lower than a predetermined temperature (here, 90°C).
0, and outputs an off signal to the relay driving means 6 when the temperature is higher than a predetermined temperature and the boiling detection condition (when the temperature rise of the sensor decreases due to boiling) is reached. Means, 8 is a relay power supply circuit.

It is composed of a resistor ea, a diode 8b, a capacitor 8a, and a constant voltage diode 8d. 9 is an AC power source. Note that the relay power supply circuit 8 includes a resistor 8a to suppress heat generation of the relay A/4.

When the relay coil (relay coil) v4 is not energized, the capacitor 8C is charged to the Zener voltage of the constant voltage diode 8d (here, d30V), and when the relay coil 4 is energized, the resistance value of the resistor 81L and the relay coil are charged. l
Due to the balance of the resistance values of relay coil 4, the balanced voltage of the voltage applied to relay coil
(here 2.4v) is higher than the voltage (here 1
The resistance value of the resistor 81L is determined to be 0'l/).

Problems to be Solved by the Invention However, in such a conventional configuration, when the voltage of the AC power supply 9 gradually rises due to restoration after construction, etc., the power supply of the relay power supply circuit 8 does not start up, and the greenhouse detection circuit 6 ．． If the power supply to the relay control means 7 starts up quickly,
When the temperature of the container 1 detected by the temperature detection means e is lower than a predetermined temperature (here, 90° C.), the relay control means 7 starts the relay drive at the time when the voltage of the relay power supply circuit 8 is lower than the sensing voltage. Since the ON signal is output to the means 6, even if the voltage of the AC power supply 9 becomes the normal voltage, the voltage of the relay power supply circuit 8 is only 1ov below the impression voltage (1e, s V ), and as a result, the relay contact 3 remains open,
There was a problem in that the heating element 2 was not energized and the water sometimes did not boil.

An object of the present invention is to provide an electric water heater that solves these problems.

Means for Solving the Problems In order to solve the above problems, the electric water heater of the present invention is configured such that when a predetermined period of time has elapsed after the relay drive means is turned on, the temperature of the container detected by the temperature detection means reaches a predetermined temperature. If not, the control means is configured to turn off the relay driving means for a certain period of time and then turn it on.

Operation Since the electric water heater of the present invention has the above-described configuration, when the relay contact is not closed even though the V-drive means is on (for example, when a foreign object is caught between the contacts, or when the AC power source is Even if the voltage reaches the normal voltage, the voltage of the relay power supply circuit will be lower than the voltage of the relay coil (1a, sV).
) When the temperature of the container detected by the temperature detection means does not reach the predetermined temperature even after a predetermined period of time has elapsed.

Since the control means turns off the relay drive means for a certain period of time and then turns it on again, the problem of no boiling can be solved.

Embodiment One embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the same parts as those shown in FIGS. 2 and 3 in the conventional example are given the same numbers, and their explanations will be omitted.

In this FIG. 1, 10 turns on the relay driving means 6;
A control means for outputting an OFF signal, and 11 a time measuring means for measuring the time from when the control means 10 outputs an ON signal to the relay driving means 6; the other configurations are the same as those shown in the conventional example. be.

First, the operation of the configuration of the embodiment shown in FIG. 1 will be explained. First, when water is put into the container 1 and the AC power source 9 is applied, the temperature of the thermistor e& is set to a predetermined temperature (90°C
) is also low, so the temperature detection means 6 outputs a low temperature signal to the control means 10.

On the other hand, the capacitor 8C of the relay power supply circuit 8 is charged to the Zener voltage (aoV) of the constant voltage diode 8d, but if the control means 1o outputs an ON signal to the relay driving means 6 during charging, the capacitor 8C Since there is a possibility that the battery will not be charged to the voltage, the control means 1o is configured to output an ON signal to the relay driving means 6 one second after the AC power supply 9 is applied. As a result, the relay coil 4 is energized and the relay contact 3 is closed, so that the heating element 2 is heated and the water in the container 1 is heated.

When the water boils, the temperature rise of the thermistor θ& stops, and the control means 1o detects the boiling as the temperature rise of the thermistor 6m decreases, outputs an off signal to the relay drive means 5, and outputs an off signal to the relay contact 3. is opened to stop the heating of the first heating element 20.

By the way, when the AC power supply 9 gradually starts up, the control means 10 outputs an ON signal to the relay drive means 6 before the capacitor 8c of the relay power supply circuit 8 is charged.
Even if the voltage of the AC power supply 9 becomes the normal voltage, the voltage of the relay power supply circuit 8's condenser/su 8c is an impressive voltage (1e, s'
i) The voltage is only below 10V, so the relay contact 3 remains open and the heating element 1 does not generate heat.

On the other hand, the time measuring means 11 measures the time after the control means 10 outputs the ON signal, and the time measuring means 11 measures the time after the control means 10 outputs the ON signal.
0 minutes), the water temperature has not risen, so
The temperature detected by the temperature detection means 6 has not reached the predetermined temperature (90°C), and the control means 1o
After outputting a 7-second signal to the phosphor drive means 5, an on-signal is output. In this case, the capacitor 8C is charged to the Zener voltage (soV) during the 1 second off period, so the relay contact 3 closes when the on signal is output.
The heating element 2 starts generating heat, and the water in the container 1 boils.

Effects of the Invention As described above, according to the present invention, the voltage of the relay power supply circuit decreases when the voltage of the AC power supply gradually rises due to restoration work, etc., when a foreign object is caught between the contacts, or when a momentary power outage occurs. When the relay contact opens and the temperature of the container detected by the temperature detection means does not reach the predetermined temperature even after a predetermined period of time has elapsed.

Since the control means turns off the relay driving means for a certain period of time and turns it on again after the voltage of the relay power supply circuit is recovered, it takes a certain period of time, but the water can be reliably boiled.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an electric water heater showing an embodiment of the present invention, FIG. 2 is a partially cutaway side view of the electric water heater, and FIG. 3 is a circuit diagram of a conventional electric water heater. 1...Container, 2...Heating element, 3...
・Relay contact. 4...Relay coil, 5...Relay drive means, 6...Temperature detection means, 10...
- Control means, 11...Time measurement means.

Claims (1)

[Claims] a container for storing water; a heating element for heating the water in the container; a relay contact for controlling the energization of the heating element; a relay driving means for controlling the energization of the relay coil; a control means for outputting an off signal;
The control means includes a time measuring means for measuring the time after outputting an ON signal to the relay driving means, and a temperature detecting means for detecting the temperature of the container, and the time measured by the time measuring means is predetermined. If the temperature of the container detected by the temperature detection means has not reached the predetermined temperature when the time comes,
An electric water heater configured such that a control means outputs an off signal to a relay drive means for a certain period of time and then outputs an on signal.