JP2001292904A - Electric water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure that protects the structural parts of an electric water heater from damage when it is used in a state being nothing of water. SOLUTION: A container 2 has a projected portion 2A at the bottom. A lid body 12 covers the opening of the container 2. A heating means 3 is arranged in the projected portion 2A, and a temperature detecting means 4 is arranged on the top of the projected portion 2A. A control means 5 controls the temperature of water. A pump 11 forces the water out from a body 1. When the water in the container 2 is decreased to the top level of the projected portion 2A, the temperature detecting means 4 arranged on the top detects the decrease and switches the heating means 3 off. If an unexpected cause prevents the heating means 3 from being switched off, the remaining water between the bottom of the container 2 and the projected portion 2A evaporated to cause extraordinary temperature elevation on the bottom and thus to elevate the temperature of the heating means 3. A thermal fuse 6 mounted on a thermal insulation plate 9 in a sandwiched relation by a holding means 7 and spaced under the heating means 3 by a metal fitting 8 detects the heat of the heating means 3 thus overheated and melts up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the safety of an electric water heater, and more particularly to abnormal heating.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a schematic structure of a conventional electric water heater. As shown in FIG.
The upper surface provided in the main body 21 is open and the bottom has a convex portion 2.
A heating means 23 for heating the water in the container 21 is provided inside the projection 22A. The container 21 is provided with a container 21 for storing water provided with 2A and a cover 27 for covering the opening of the container 21.

A pump 24 and a spout 25 for guiding water in the container 21 to the outside of the main body 21 are provided, and the water is discharged from the main body 21 by operating the pump 24 by the operating section 26. The water in the container 21 gradually decreases with use and finally reaches the upper surface of the convex portion 22A at the bottom of the container 22. The temperature detecting means 28 disposed on the upper surface detects a high temperature because there is no water. The heating means 23 is turned off. However, if the heating means 23 is not turned off for some unexpected reason, the temperature fuse 27 detects an abnormal temperature rise at the bottom surface due to evaporation of the substantially annular residual water reservoir between the bottom surface of the container 22 and the convex portion 22A. Detects and turns off the power to heating means 23
This is a configuration to prevent accidents by FF.

[0004]

However, the temperature fuse 2
Since the remaining water in the container 22 almost evaporates and the temperature rises until the operation of the heating unit 7 takes a considerable time, the heating means 23 continues to be in the heating state during that time. 23 may be damaged by its own heat. The heating means 23 is expensive and requires a great deal of trouble during repair. This is more likely to occur if the water heater is installed at an angle.

Therefore, there is a problem that it is more preferable to always operate the temperature fuse before the heating means is damaged.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is fixed to the bottom of a container for storing water so as to accurately maintain a predetermined space below a heating means disposed on the back surface of the container. The temperature fuse is attached to the fixing bracket together with the heat insulating plate and fixed below the container.

According to the present invention, the temperature fuse surely detects an abnormal temperature and cuts off the power supply even if heating is performed in a state where the water in the container is exhausted by the above-mentioned means, thereby damaging the heating means which is expensive and very difficult to repair. It can be solved by replacing the temperature fuse only.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a main body, a container for storing water having a convex portion at the bottom in the main body, a heating means provided in contact with the back surface of the convex portion of the container, Temperature detecting means for detecting the temperature of water, control means for detecting a set temperature of water in the container and stopping or activating the heating means, and connected to an energizing circuit of the control means to cause the heating means to overheat. A temperature fuse that detects when it has reached and blows,
Holding means for maintaining a spatial distance from the heating means and narrowing a temperature fuse to be brought close to the heating means.

The temperature fuse directly receives heat radiation from the heating means and also operates reliably due to a rise in ambient temperature, so that the heating means is not damaged.

The temperature fuse narrowed by the holding means includes a fixing member provided integrally with the bottom rear surface of the container for storing water, and a heat insulating plate provided below the heating means. The heating plate is made in close contact with the heat-insulating plate, and is integrally formed with the fixing bracket so as to maintain a spatial distance between the temperature fuse and the heating means.

[0011] The heating means and the temperature fuse are securely attached by the fixture and can be maintained at a constant distance, so that the temperature fuse operates with little temperature variation.

Further, the temperature fuse penetrates through the insulating tube, is narrowed by the holding means, and a portion of the holding means other than the narrow portion is in close contact with the heat insulating plate.

[0013] Since the holding means is adhered to the heat insulating plate, the influence of the ambient temperature is small.

[0014] Further, the holding means for the temperature fuse, which is narrowly placed via the insulating tube, opens the surface facing the heating means,
The opening in the longitudinal direction of the temperature fuse alone is larger than the temperature fuse alone.

By enlarging the opening, the radiant heat from the heating means is sufficiently received, and the temperature fuse itself is securely fixed in the insulating tube.

Further, the insulating tube is colored. Since the amount of radiant heat received differs depending on the color, delicate temperature control can be performed by selecting the color.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing a cross section and an appearance of a main part of an electric water heater according to Embodiment 1 of the present invention. Body 1
And a container 2 for storing water provided in the main body 1 with an open upper surface and provided with a convex portion 2A at the bottom, and a lid 12 for covering the opening of the container 2. A heating means 3 for heating is provided inside the convex portion 2A. A temperature detecting means 4 is provided on the upper surface of the convex portion 2A and is connected to a control means 5 to control the temperature of water in the container 2. In addition, a pump 11 and a spout 13 for guiding water in the container 2 to the outside of the main body 1 are provided.
The pump 11 is operated by the operation unit 14 to discharge water out of the main body 1. The water in the container 2 gradually decreases with use and finally reaches the upper surface of the convex portion 2A at the bottom of the container 2, and is detected by the temperature detecting means 4 arranged on this upper surface to have a high temperature because there is no water. The heating means 3 is turned off. However, for some unexpected reason, the heating means 3
If not, the abnormal temperature rise of the bottom surface due to the evaporation of the substantially annular residual water pool between the bottom surface of the container 2 and the convex portion 2A starts, and the temperature of the heating means 3 also rises. The temperature fuse 6 sandwiched by the holding means 7 is attached to the heat-insulating plate 9 via the fixing bracket 8 attached to the container 2 so as to provide a space 9 below the heating means 3 and integrated with the screw 10 to overheat the temperature fuse 6. The detected heat of the heating means 3 is detected and the power supply to the heating means 3 is turned off to prevent the heating means 3 from being damaged.

(Embodiment 2) FIGS. 2 (a), 2 (b) and 2 (c) are views showing the mounting state of a temperature fuse according to Embodiments 2 and 3 of the present invention. The temperature fuse 6 penetrates through the insulating tube 10, is narrowed by the holding means 7, and a portion of the holding means 7 except for the narrow portion is configured to be in close contact with the heat shielding plate 9. The space temperature between the containers 2 is kept constant, and the temperature of the holding means 7 is also kept constant.

(Embodiment 3) As shown in FIG. 2, the holding means 7 for the temperature fuse 6 narrowly mounted via the insulating tube 10 has a large opening on the surface facing the heating means 3 and the longitudinal length of the temperature fuse 6 alone. The opening in the direction is made larger than the temperature fuse 6 alone, so that the heat radiation from the heating means 3 can be reliably detected.

Further, the operating temperature of the temperature fuse 6 can be slightly changed by selecting the color of the insulating tube 10 so as to easily absorb radiant heat.

[0022]

As described above, according to the present invention, even if the electric water heater is erroneously used until the water runs out, or even if the temperature detection does not work, it can be used on an inclined surface. At worst, the temperature fuse only activates and does not damage other parts.

[Brief description of the drawings]

FIG. 1 is an external view and a partial sectional view of a first embodiment of the present invention.

FIG. 2A is a top external view showing a mounting state of the temperature fuses of Examples 2 and 3; FIG. 2B is a side external view showing a partial cross section of the mounting state of the temperature fuses; FIG. The bottom view

FIG. 3A is a cross-sectional view showing a configuration of a conventional electric water heater, and FIG. 3B is a cross-sectional view showing a state in which the same temperature fuse is mounted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Container 2A convex part 3 Heating means 4 Temperature detection means 5 Control means 6 Temperature fuse 7 Holding means 8 Fixing metal 9 Heat insulation plate 10 Insulation tube 11 Pump

Claims (5)

[Claims] 1. A main body, a container for storing water having a convex portion at the bottom in the main body, a heating means provided in contact with the back surface of the convex portion of the container, and a temperature of the water in the container. Temperature detecting means for detecting, a control means for detecting a set temperature of water in the container and stopping or activating the heating means, and connecting to an energizing circuit of the control means to detect that the heating means has reached an overheated state. An electric water heater comprising: a temperature fuse to be detected and blown; and holding means for narrowing the temperature fuse to be maintained and kept in contact with the heating means. 2. A temperature fuse narrowed by a holding means, comprising: a fixing metal provided integrally with a bottom rear surface of a container for storing water; and a heat insulating plate provided below a heating means. 2. The electric water heater according to claim 1, wherein the heater is in close contact with the heat shield plate and is integrally formed with the fixing bracket to maintain a spatial distance between the temperature fuse and the heating means. 3. The electric water heater according to claim 2, wherein the temperature fuse penetrates through the insulating tube, is narrowed by the holding means, and a portion of the holding means other than the narrow portion is in close contact with the heat-insulating plate. . 4. A temperature fuse holding means which is narrowly mounted via an insulating tube has an opening on a surface facing the heating means, and a longitudinal opening of the temperature fuse alone is larger than the temperature fuse alone. Item 3. An electric water heater according to item 3. 5. The electric kettle according to claim 4, wherein the insulating tube is colored.