JPS632845Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electric water heater that can stop supplying electricity to the heater after raising water to boiling temperature.

Conventionally, in the case of electric water heaters, electricity was continuously applied to the heater to raise the water to boiling temperature, and then a manual switch was used to stop the electricity to the heater, or a timer was used to turn the electricity to the heater after a set time elapsed. However, with the former, there was a problem of forgetting to turn off the manual switch, and with the latter, the approximate boiling time was determined based on past experience and instruction manuals, etc., and the timer was set. The operation was unstable, and it was especially difficult to set the time due to changes in water temperature, room temperature, water volume, etc.

It is also possible to sense the temperature of the water in the container with a heat-sensitive element (for example, a thermostat) and stop energizing the heater when the boiling temperature is reached, but even with this type of water, the following This causes problems such as: In other words, there is a tolerance in the operating temperature of a thermostat. For example, if the nominal operating temperature is ±3°C, the nominal operating temperature is 100°C, and if you use a thermostat that is OFF, there will be a thermostat that is OFF. As a result, the thermostat may not turn off even when the boiling temperature is reached, or the thermostat may turn off before the boiling temperature is reached.
This resulted in variations from product to product, such as being turned OFF, and was unreliable.

This proposal was made in view of these points,
Embodiments of the present invention shown in the drawings will be described in detail below.

First, in FIG. 1, reference numeral 1 denotes an inner container of an electric water heater or an electric hot water heater, which stores water. Reference numeral 2 denotes a heater that heats and raises the temperature of water in the inner container 1, and is installed on the outer peripheral surface of the lower part of the inner container 1. Reference numeral 3 denotes a spacer made of a thermal insulator or a material with a large heat capacity, and is provided at the center of the outer bottom surface of the inner container 1. 4 is a thermostat that senses the temperature of the water inside the inner container 1 via the spacer 3 and controls the energization to the heater 2. For example, the thermostat is set at a nominal operating temperature (96°C,
OFF).

Figure 2 is a diagram showing the relationship between time and temperature.
A shows the change in the temperature of the water inside the inner container 1, and B shows the change in the temperature of the thermostat's heat-sensitive part. It has a time delay. T ₀ indicates the nominal operating temperature of the thermostat 4, T ₁ indicates the upper tolerance limit of the thermostat 4, and T ₂ indicates the lower tolerance limit. Therefore, in this embodiment, when the upper limit temperature of the thermostat heat sensitive part exceeds the tolerance upper limit _T1 of the thermostat 4 and the water temperature reaches the boiling temperature, the temperature of the thermostat heat sensitive part is Tatsuto 4 tolerance lower limit
The material of the spacer 3 is selected so that it is lower than _T2 .

With the above configuration, the hot water in the inner container 1 can be reliably heated to boiling temperature not only when the thermostat 4 is at the nominal operating temperature, but also when the thermostat 4 is at the upper or lower tolerance limit. It is possible,
Moreover, although there is a slight time lag after boiling, the power supply to the heater 2 can be automatically stopped and heating can be completed.

Note that the heat sensitive element is not limited to a thermostat, but a thermal reed switch or the like may also be used.
In addition, when implemented in an electric hot water heater, the water temperature is configured so that once boiling, the thermostat is operated to switch to the heat retention circuit, and from then on, the water temperature can be controlled to the warm temperature by the heat retention circuit. .

According to the present invention having the above configuration, although there is a tolerance in the operating temperature of the heat-sensitive element, the operation of stopping the power supply to the heater after boiling water is reliably performed using a simple structure using the heat-sensitive element. This is an extremely practical option.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the main parts of the water heater of the present invention, and FIG. 2 is a diagram showing the relationship between time and temperature. 1: Inner container, 2: Heater, 3: Spacer, 4:
Thermostat (heat sensitive element).

Claims (1)

[Scope of utility model registration request] A heater that heats and raises the temperature of water in the container, a spacer made of a thermal insulator or a material with a large heat capacity, and a temperature of the water in the container is sensed through the spacer,
an electric water heater, comprising: a heat-sensitive element having an operating temperature slightly lower than the boiling temperature for controlling energization to the heater, and configured so that the heat-sensitive element stops energization to the heater after boiling. .