JPS6340182Y2 - - Google Patents

Description

[Detailed explanation of the idea] Industrial applications The present invention relates to an electric water heater.

Conventional technology Conventionally, this type of electric water heater was
As shown in Publication No. 37138, it had a configuration as shown in FIG. In other words, this third
In the figure, 1 is a heating element for boiling water provided at the bottom of a water boiling container (not shown), and a switch circuit 2
It is connected to the AC power supply 3 via. A temperature detector 4 detects the temperature of the water and outputs a signal corresponding to the temperature of the water, and is composed of a temperature-sensitive resistance element 5 and a fixed resistor 6. 7 is a comparator whose input is a signal directly derived from the temperature sensor 4;
The output signal from the comparator 7 is transmitted to the relay 11 via the transistor 10 of the switch control circuit 9.
is operated, and the switch circuit 2 is turned on and off to control the power supply to the heating element 1. 12 is a DC power supply for operating the aforementioned circuit.

In the above-described configuration, water is first poured into a water boiling container (not shown), and when power is applied to the heating element 1, water boiling begins. At this time, the output signal of the temperature detector 4 increases until it reaches a boiling state, as shown by the curve 13 in FIG. 4, and when the boiling point is reached, the water temperature becomes constant, so the output also becomes constant. The signal passing through the delay circuit 8 becomes like the curve 14 in FIG. 4, and changes in the same way as the output signal 13 of the temperature detector 4 after a certain fixed time delay. When these two signals are applied to comparator 7, its output is as shown by curve 15 in FIG. Therefore, the switch control circuit 9 turns on the switch circuit 2 when electricity starts, and when the water boils progresses and the output of the comparator 7 becomes zero, it turns off the switch circuit 2. Completed and always boiled for a certain amount of time.

Problems to be Solved by the Invention In such a conventional configuration, when water is added and immediately heated, the output signal of the temperature detector 4 decreases as the water temperature decreases, but the delay circuit 8
Since the signal passed through the boiler indicates the temperature at which the water is boiling for a certain period of time, there is a problem in that boiling water cannot be started until these two signals are at the same level.

This invention solves these problems,
To provide an electric water heater that has a simple configuration, can start boiling water immediately even after adding water after boiling water, and does not degrade boil detection performance.

Means for Solving the Problems In order to solve the above problems, the electric water heater of the present invention includes a heating element for boiling water connected to a power source via a switch circuit, and a temperature of the water heated by this heating element. A temperature detector that detects the temperature, a delay circuit that delays the signal of this temperature detector for a certain period of time, a signal from this delay circuit and a signal of the temperature detector, and the output signal controls the switch circuit. It is composed of a comparator to control, a water boiling switch that starts water boiling, and a timer circuit that is reset by the water boiling switch, outputs an output for a predetermined period of time, and controls the switch circuit using the output signal.

Effect: With this configuration, when you press the water boiling switch, the heating element is always energized for a predetermined period of time, and during that time, the signal from the temperature sensor and the signal passed through the delay circuit can be corrected, so water is added after the water has been boiled. To provide an electric water heater that can start boiling water immediately after heating and does not deteriorate boiling detection performance.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Components in FIGS. 1 and 2 that are the same as those in FIGS. 3 and 4 shown in the conventional example are designated by the same reference numerals, and their explanations will be omitted. 1st
2, 16 is a timer circuit that outputs for a predetermined period of time and controls the switch circuit 2 with its output signal, and includes a second comparator 17 with an open collector output, a charging resistor 18, and a capacitor 1.
It is composed of 9 mag. Reference numeral 20 denotes a water boiling switch that starts boiling water, and is connected in parallel with the capacitor 19.

In the above configuration, the operation will be explained next. First, water is poured into a water boiling container (not shown) and electricity is applied to the heating element 1 to start boiling water. The output signal of the temperature detector 4 at this time is as shown by the curve 13 in FIG. The signal passing through the delay circuit 6 becomes like the curve 14 in FIG. 2, and changes in the same way as the output signal 13 of the temperature detector 4 after a certain fixed time delay. When these two signals are input to the comparator 7, the output is as shown by the curve 15 in FIG. Therefore, the switch control circuit 9 controls the switch circuit 2 at the start of energization.
The switch circuit 2 is turned OFF when the boiling water progresses and the output of the comparator 7 reaches zero. In this way, after boiling is detected, when water is added and the water boiler switch 20 is pressed, the two input signals of the comparator 7 become as shown in Figure 2, and the output remains zero, but during this time , the switch control circuit 9 is operated for a predetermined period of time by the timer circuit 16.
If you set the predetermined time of the timer circuit 16 so that when the timer circuit 16 turns OFF, the switch circuit 2 is turned ON by the output of the comparator 7, you can boil the water from the water mentioned above. It will be the same as if you did.

Therefore, even after adding water after boiling, boiling can be started immediately without degrading boil detection performance.

Effects of the invention As described above, according to the invention, it is possible to start boiling water immediately after boiling water, even after adding water, and boiling water is always maintained for a certain period of time. This is something that can be improved.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of an electric water heater showing an embodiment of the present invention, Figure 2 is a diagram showing the output signals of each part, Figure 3 is a circuit diagram of a conventional electric water heater, and Figure 4 is a diagram of its various parts. It is a figure which shows the output signal of. 1... Heating element, 2... Switch circuit, 4... Temperature detector, 7... Comparator, 8... Delay circuit, 16
...Timer circuit, 20 ... Water boiling switch.

Claims (1)

[Scope of utility model registration request] A switch circuit, a heating element connected to a power source via this switch circuit, a temperature detector that detects the temperature of water heated by this heating element, and a delay circuit that delays the signal of this temperature detector for a certain period of time. A comparator that compares the signal from this delay circuit with a signal from the temperature sensor and controls the switch circuit based on the output signal, a water boiling switch that starts boiling water, and a water boiling switch that is reset by this water boiling switch. and a timer circuit that outputs an output signal for a predetermined period of time and controls the switch circuit using the output signal.