JPS646766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to electric water heaters such as so-called jar pots that heat and keep hot water within a volume. This relates to a boiling type electric water heater that retains heat.

(Prior art) In general, in order to bring out the taste and aroma of tea, coffee, black tea, etc., it is necessary to remove the unique taste caused by limescale, etc. in tap water, and as a means to remove such a unique taste, It is widely known that tap water can be boiled, and a boiling type is desired even in electric water heaters such as jar pots.

Currently, various boiling type water heaters have been proposed as this type of water heater. In most cases, the heater is continuously energized and brought to a boil within that time, and in both cases, the user has to manually operate the heater, which can lead to problems such as overboiling or forgetting to turn off the switch, which is extremely dangerous. There was a risk that a serious situation could arise.

(Object of the present invention) The present invention has been made in view of the above points, and after boiling the hot water in the container, it automatically controls the heating means and switches to the heat retention state to maintain the temperature at a predetermined temperature. It is characterized in that it keeps the water warm, prevents problems like those in the past, and allows the hot water to be re-boiled at will by a simple switch operation.

(Example) Examples of the present invention shown in the drawings will be described in detail below.

First, in the electrical circuit diagram shown in Figure 1, 1 is an AC power supply, 2 is a main heater that heats the hot water in the container,
Reference numeral 3 denotes a heat retaining heater which generates a smaller amount of heat than the main heater 2, and together with the main switch 2 constitutes a means for heating hot water. 4 is a thermal reed switch, such as a thermal reed switch, which controls the energization of the heat insulating heater 3 according to the temperature change of hot water and maintains it at a predetermined temperature (for example, 90°C); 5 is a thermal switch that senses an abnormal temperature rise in the container, and
6 is a temperature fuse that blows out at a temperature higher than that of the thermostat 5, 7 is a relay switch that turns on when the relay coil is energized, and 8 is the thermal switch 4, which turns OFF at about 130℃. Thermal switches such as normal-temperature closed thermostats that turn off at a temperature lower than the operating temperature (e.g. 85°C), 9
is a normally open type reboiling switch that is turned ON only when pressed, and a series circuit consisting of a main heater 2 and a relay switch 7 is connected between both terminals of the AC power supply 1.
An overtemperature rise prevention thermostat 5 and a temperature fuse 6 are inserted and connected in series so that the series circuit consisting of the heat retention heater 3 and the thermal switch 4 is connected in parallel, and the relay switch 7 is connected in series. switch 8
and reboiling switch 9 are connected in a parallel relationship. Therefore, relay switch 7 and thermal switch 8
Or at least one of the reboiling switches 9 is ON.
At this time, a heating circuit, that is, a heating boiling circuit is formed by both the main and heat retention heaters 2 and 3, and each switch 7,
When both 8 and 9 are OFF, a heating circuit is formed using only the heat-retaining heater 3, that is, a heating and heat-retaining circuit. 10
1 is a main heater energization indicator lamp, and 11 is a heat retention indicator lamp.

12 is a step-down transformer whose primary side is connected in parallel to the main heater 2, and whose secondary side is a diode 1.
3. A DC power supply circuit consisting of a capacitor 14 and a constant voltage diode 15 is connected by interposing a lid switch 16 and a selection switch 17 in series. The lid switch 16 is a switch that is linked to the lid that opens and closes the opening of the container, and the selection switch 17 is a switch that is manually turned on and off.

18 is a heating switching control circuit connected to the DC power supply circuit. In this control circuit 18, 19
is a transistor, 20 is a relay coil inserted between the cathode of the constant voltage diode 15 and the collector of the transistor 19, 21 is a diode connected in parallel to the relay coil 20, and 22 is a sensor for detecting the generation of steam during boiling, such as a positive A characteristic thermistor, 23 is a resistor, 24 is a Schmitt trigger circuit for stabilizing operation, consisting of two CMOS inverters 25, 26 and a resistor 27, and the input side is connected to the connection point between the thermistor 22 and resistor 23 via a resistor 28. ,
The output sides are connected to the bases of transistors 19 via resistors 29, respectively.

Next, in FIG. 2, 30 is a container containing hot water, 31 is an outer case in which the container 30 is placed, and 3
Reference numeral 2 denotes an inner plug detachably fitted into the opening of the container 30, forming a steam passage 33. 34 is a lid that closes the opening of the container 30, which forms a steam outlet 35 connected to the steam passage 33 when closed;
A thermistor 22 is disposed at. 36 is the container 30
It is a belt-shaped heating body wrapped around the lower outer periphery of the main heater 2 and the heat-retaining heater 3. 37 is the spout,
38 is a handle. Therefore, a thermostat 5 to prevent excessive temperature rise and a temperature fuse 6 are installed on the outer bottom surface of the container 30.
Further, thermal switches 4 and 8 are provided on the outer surface, respectively. Although the lid switch 16 is not shown in FIG. 2, it is linked to the opening and closing of the lid 34 and is turned ON when the lid 34 is closed.

(Operation of Example) First, a case will be described in which hot water is once boiled and then kept at a predetermined temperature.

After opening the lid 34 and removing the inner stopper 32 and storing a predetermined amount of tap water in the container 30, the lid switch 16 is turned on by fitting the inner stopper 32 and closing the cover 34.
, then manually turn on selection switch 17.
Manipulate the state. When the power is turned on in this state, both the thermal switches 4 and 8 are in the ON state, so the main heater 2 and the insulation heater 3 are energized and the container 30 is turned on.
At the same time, the resistance of the thermistor 22 in the relay coil 20 is small, so that a base current flows through the transistor 19, and accordingly, the relay switch 7 is turned on.

As the heating progresses and the temperature of the hot water eventually rises to 85°C, the temperature of the hot water is sensed and the thermal switch 8 is turned off. However, the relay switch is ON.
Since the main heater 2 is in this state, power continues to be applied to the main heater 2, and heating by both heaters 2 and 3 continues.

When the temperature of the hot water further rises to 90° C., the thermal switch 4 is turned off to cut off the power supply to the heat-retaining heater 3, and the main heater 2 continues to heat the water. As this heating continues, the hot water will eventually begin to boil, and the steam generated by the boiling will blow outward through the steam passage 33 of the inner stopper 32 and the steam outlet 35 of the lid 34, and this steam will be detected. As a result, the resistance value of the thermistor 22 increases rapidly. Then, the base current no longer flows through the transistor 19 and the transistor 19 becomes OFF, and accordingly, the relay coil 20 is de-energized and the relay switch 7 is turned off.
Turn OFF to switch from heating and boiling state to heating and keeping warm state. That is, the heating by the main heater 2 is stopped and the heating circuit is switched to the heating circuit by the heat retaining heater 3. Furthermore, at the time of switching, the temperature is high and the thermal switch is turned off, so the thermal heater 3 does not heat up immediately, but resumes heating when the temperature drops and the thermal switch 4 is turned on. From then on, the hot water will be kept at a temperature of 90°C by being controlled by turning the thermal switch ON and OFF.

In this way, once the hot water has been brought to a boil, it can be kept at a predetermined temperature.

Next, when hot water is taken out and cold water is replenished in the heat-retaining state, the temperature of the hot water in the container 30 drops significantly. In such a case, the thermal switch 8 immediately senses the temperature drop and turns on, and the heating switching control circuit 18 operates at the same time as switching from the heating and warming state to the heating and boiling state. At this time, the temperature of the thermistor 22 has decreased and the resistance value has become smaller, so the transistor 19
It becomes ON state and relay switch 7 also becomes ON,
The operation described in the previous step is carried out to bring the water to a boil and then keep it warm at a predetermined temperature.

In addition, if you wish to re-boil the hot water when taking it out in the warm state, if you temporarily turn on the re-boiling switch 9 and operate the heating switching control circuit 18, the relay switch 7 will turn on and the boiling state will be restored. The water will be boiled in the same way as described above, and the hot water can be taken out.

When boiling water, if boiling is not necessary, turn off the selection switch 17. By doing this, the heating switching control circuit 18
does not operate and the relay switch 7 remains OFF, so the main heater 2 and the heat retention heater 3 are heated to quickly raise the temperature until the temperature of the hot water reaches the operating temperature of the thermal switch 8. After that, the heat is heated by the heat retention heater 3, and the thermal switch 4 is turned on.
By turning it on and off, it will be kept at a warm temperature and will not boil.

Furthermore, even if the lid 34 is not completely closed and the lid switch 16 remains OFF, the hot water is heated to the heat retention temperature and remains at that temperature in the same way as when the selection switch 17 is OFF. preserved and never boils. In such a case, if it is boiled, there is a risk that steam will escape through the gap between the outer case 31 and the lid 34 and the thermistor 22 will not be able to detect the generation of steam. For this reason, the structure is designed to prevent boiling to prevent the dangerous situation of continuous boiling.

(Effects of the present invention) As described above, in the present invention, once the hot water in the container is boiled, the heating means is automatically controlled to switch to the warm state, and the heat can be kept at a predetermined temperature. In addition, when you take out the hot water that is being kept warm, you can simply operate the normally open reboiling switch to bring it back to a boil. After boiling again, it automatically returns to the heat-retaining state as in the case of once boiling, so it is possible to avoid the danger of continued boiling.

Furthermore, since the heating switching control circuit that once boils the hot water and switches to the heat retention state is also used as a means for returning from reboiling to the heat retention state, the configuration can be simplified.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can of course be implemented with appropriate modifications within the scope of the gist.

[Brief explanation of drawings]

Figure 1 is an electric circuit diagram of the electric water heater of the present invention, Figure 2 is an electric circuit diagram of the electric water heater of the present invention.
The figure is a schematic configuration explanatory diagram of the same as above. 2: Main heater, 3: Heat retention heater, 7: Relay switch, 9: Reboiling switch, 18: Heating switching control circuit, 19: Transistor, 20: Relay coil, 22: Thermistor (sensor), 30: Container.

Claims (1)

[Scope of Claims] 1. A heating means for heating hot water in a container, a sensor for detecting boiling of the hot water, and a heating means for controlling the heating by the heating means from a boiling state by detecting boiling. A heating switching control circuit that switches to a heating and keeping warm state; and a normally open reboiling switch that manually controls the heating switching control circuit and operates to switch the heating by the heating means from the heating and keeping warm state to the heating and boiling state. An electric water heater characterized by comprising: