JPH0698094B2 - Electric water heater - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater such as a jar pot or an electric kettle that boils hot water and then keeps it warm.

2. Description of the Related Art Conventional electric water heaters of this type are equipped with a stainless steel single-layer hot and cold water storage container that is surrounded by a heat insulating material, take out steam when water is boiling, and detect the steam temperature with a temperature detector. However, it is known that the main heater is shut off and the warm heater is continuously energized to slow down the rapid decrease in hot water temperature and maintain the hot water temperature at a point where the heat release amount and the heat generation amount of hot water of about 90 ° C are balanced. There is.

Problems to be Solved by the Invention According to the above-mentioned configuration, various problems have arisen because the heat insulating property of the container for storing hot water is insufficient. In other words, when the product is used in cold regions, in order to maintain the prescribed hot water temperature,
It required 10 to 20 watts of warming power larger than the rated warming power, and when it was used at the rated warming power, it could not maintain the predetermined warming temperature and re-energized the main heater to repeat boiling and warming. In addition, when the product is used in a high temperature area, in order to maintain the specified hot water temperature, conversely, a heat insulation power that is about 10 W smaller than the rated heat insulation power is required. Beyond the temperature, it will be in a weak boiling state. In such a container for storing hot and cold water with poor heat insulation, not only is it not always possible to maintain the prescribed heat retention temperature depending on the ambient temperature, but in some cases, the lid part of the product, the steam passage, etc. may exceed the rating and the temperature may rise. Since it is exposed to various steam, deterioration of plastic parts is accelerated, various defects are caused, and product life is shortened. For this reason, in products equipped with an air pump, the amount of steam generated during heat retention is much larger, so steam enters the bellows of the air pump and becomes water droplets, which causes death and water decay, which is not desirable for hygiene. . Furthermore, a large amount of steam has various problems such as a decrease in the amount of water during heat retention, a decrease in reliability of electric parts, and an increase in indoor humidity. In addition, the heat insulation power of 2.2l capacity requires about 30-40W, which is by no means a power-saving product.

Means for Solving the Problems The present invention improves the drawbacks of the above-mentioned conventional techniques.
By making the container for hot and cold water storage a container with a vacuum insulation layer, after boiling water in the container, the warming heater is automatically energized continuously to maintain the warming condition and the ambient temperature can be maintained with a small amount of warming power. The temperature is always kept stable without being affected by the temperature. When the hot water temperature drops due to the supply of cold water, it is automatically boiled by the main heater and then kept warm by the warm heater. When the re-boil switch is operated, the hot and cold water is forcibly boiled to maintain the temperature thereafter, and it is possible to maintain a sufficiently high hot water temperature in actual use even when the power is not supplied.

Operation With the above-mentioned configuration, the hot water in the container is boiled once, and then the heat insulation heater is automatically energized continuously to maintain the heat insulation state, and a slight heat insulation power does not affect the ambient temperature and the amount of water. When the temperature is maintained at a high temperature or when the temperature drops due to the supply of cold water, the main heater automatically boils and then the heat-retaining heater maintains the heat-retaining state.

Furthermore, even when the power is not supplied, the hot water temperature can be maintained which is sufficiently satisfactory for practical use. Further, by operating the re-boiling switch from the heat retention state, the boiling state can be freely set at any time.

Embodiment One embodiment of the present invention will be described below with reference to the drawings.

The structure of the embodiment is as shown in FIGS. 1 and 2.
1 is a vacuum heat insulation layer, 2 is a container for hot and cold water storage having the vacuum heat insulation layer 1, 3 is a main heater of about 800 W for boiling water, 4 is a heat retention heater of about 8 W for heating and keeping hot water, 5 is supply of cold water The second temperature detector consists of a boiling water thermo switch that detects when the hot water temperature drops below a predetermined temperature, 6 is an air-fired thermo switch that detects this when the heater is air-fired, 7 is a temperature fuse, 8 is a first temperature detector consisting of a steam thermo switch for detecting steam when boiling water in the container 2 for storing hot water, 9 is a relay for switching between heating by the main heater 3 and heating by the heat retaining heater 4, 10 is heat retaining Heater 4
It is a normally open reboil switch that switches from heating by the main heater 3 to heating only by pressing.
Reference numeral 11 denotes a relay coil of the relay 9, which is connected in series to the first temperature detector 8. A relay contact 12 of the relay 9 is connected in parallel to the second temperature detector 5. 13 is an AC power supply.

The operation of this embodiment having the above configuration will be described with reference to the circuit of FIG.

When a tree is put in the container 2 for storing hot water and electricity is applied, the second temperature detector 5 and the first temperature detector 8 are closed, so that the AC power supply 13 is applied to the main heater 3 and the main heater 3 Since the heat is generated and the water temperature rises, and at the same time, the relay coil 11 is energized, the relay contact 12 is closed. When the water temperature rises gradually, first the second temperature detector 5 consisting of a thermo switch for boiling water turns off at around 90 ° C. Hot water temperature is 100
When the temperature reaches ℃, the amount of hot water heated at about 800W suddenly begins to emit high-temperature steam, and the first type consists of a steam thermoswitch.
The temperature detector 8 detects the temperature and turns off. Third
In the figure, the water temperature is shown by the solid line and the steam temperature is shown by the dotted line. Then, the relay coil 11 is de-energized and the relay contact 12
Is turned off, and since the main heater 3 and the warming heater 4 are connected in series, the hot water is mainly heated by the warming heater 4 due to their resistance ratio. The heating power at this time is about 8W
Since the container 2 for hot and cold water storage has the vacuum heat insulation layer 1, it has a very good heat retaining ability, and the heat retaining heater 4 of about 8 W provides a heat amount equivalent to the amount of heat radiated from the electric water heater at a water temperature of 95 ° C. It can be supplied, and a constant hot water temperature can be maintained regardless of the ambient temperature. On the other hand, about 800W
The high temperature, large amount of steam generated by the main heater 3 of the
The temperature drops to and turns on again. However, since the second temperature detector 5 remains off, the relay contact 12 is turned off.
The current that keeps it from flowing does not flow and the heat retention state is maintained thereafter.
Now, if the cold water is added by the use of hot water, the hot water temperature drops, and when the temperature drops below 85 ° C, the second temperature detector 5 is turned on, and the first temperature detector 8 is already turned on. Therefore, it becomes the initial state, and the temperature is maintained after boiling the hot water with the main heater 3 of about 800W. Further, since the container 2 is formed from the vacuum heat insulating layer 1, the hot water once boiled can maintain the hot water temperature of 90 ° C. or higher for about 4 hours even without the AC power supply 13. In addition, when used for a long time without the AC power supply 13 and then boiling water, by turning on the reboil water switch 10, even when the second temperature detector 5 is off, the relay coil 11 is energized and the relay contacts are turned on. Since 12 is turned on and self-holding, even when the reboil switch 10 is turned off, the main heater 3 is energized through the relay contact 12 to boil the hot water and then keep it warm.

EFFECTS OF THE INVENTION As described above, according to the present invention, a container having a vacuum heat insulating layer having excellent heat retention, a main heater, a heat retention heater, a first temperature detector for detecting a steam temperature, and a decrease in hot water temperature are detected. By providing a second temperature detector and a re-boil switch, stable hot water is maintained without boiling a large amount of steam when the water inside the container is vigorously boiled and then is affected by the ambient temperature. Can be done. Moreover, the heat-retaining power is about 1/4 of the heat-retaining power in the past, and moreover, it is possible to keep the same heat as the conventional boiling jar pot for about 4 hours even when there is no power supply, which is extremely efficient.
It has the effect of making it an economical electric water heater.

[Brief description of drawings]

FIG. 1 is a side sectional view of an electric water heater showing an embodiment of the present invention, FIG. 2 is an electric circuit diagram thereof, and FIG. 3 is a correlation state diagram of the water temperature, steam thermoswitch temperature and heater power. . 1 ... Vacuum insulation layer, 2 ... Container, 3 ... Main heater, 4 ... Insulation heater, 5 ... Second temperature detector, 8 ... First temperature detector, 10 ... Reboil switch .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seio Kaneko 3-3 Shinjuyoji, Kashiwa-shi, Chiba Hitachi Thermal Equipment Co., Ltd. Hisanao Tanaka (56) Reference JP-A-59-151920 (JP, A) 58-185155 (JP, U)

Claims (1)

[Claims] 1. A container (2) having a vacuum heat insulation layer (1) is provided, a main heater (3) for boiling water, a heat retaining heater (4) for maintaining a weak boiling state, and boiling water A first temperature detector (8) for detecting and a second temperature detector (5) for detecting when the hot water temperature falls below a predetermined temperature are provided, and a heating and boiling state by the main heater (3) is provided. By detecting with the first temperature detector (8) and keeping it warm by the heat retention heater (4), by detecting with the second temperature detector (5) when the hot water temperature falls below a predetermined temperature. An electric water heater equipped with a re-boiling switch (10) for switching to a heating and boiling state by only the main heater (3) and for switching from a heat retention state to a boiling state by energizing the main heater (3) .