JP3136954B2 - Electric water heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a household electric water heater for heating and keeping a liquid contained therein.

[0002]

2. Description of the Related Art In recent years, electric water heaters that heat water to keep it warm have become widespread. The heating element provided in the electric water heater had a configuration as shown in FIGS. Hereinafter, the configuration of a heating element mounted on a conventional electric water heater or the like will be described with reference to FIGS. 4, 5, and 6. FIG.

[0003] A heat dissipating plate 104 having both sides covered by an insulating material 103 is disposed on the back surface of a heat transfer plate 102 formed so as to protrude from the center of the bottom surface of the container 101 of the electric water heater, and a heat diffusion plate having good heat conductivity. The heat generating portion 10 is provided on the bottom surface of the thin heat transfer plate 102 and the container 101 by the seam plate 106 through the
4 is fixed by welding so as to pinch and fix. Further, the heat generating portion 104 is configured by winding a heat generating wire 108 around a substrate 107. Also, both ends 108A of the heating wire 108,
108B is connected to the power supply unit.

[0006] As shown in FIG. 6, the heating wire 1 shown in FIG.
Instead of 08, a heating element is constituted by a metal foil heating element 109 formed by punching a high-resistance thin metal plate in a meandering strip shape, and there is also a reasonable heating element without using the substrate 107 in FIG.

[0005]

When the liquid (water) is heated on the surface of the heat transfer plate 106, a bubble of water vapor is generated on the surface of the heat transfer plate. Depart from the surface. At that moment, it is rapidly cooled by the liquid, and the bubbles rapidly shrink and disappear. Also, when the temperature of the liquid increases, the detached bubbles burst on the water surface.

[0006] As described above, when the liquid in the container 101 is heated, a large amount of bubbles generated at the time of boiling water are repeatedly extinguished and burst. As a result, the liquid vibrates, thereby continuously vibrating the bottom of the container, generating a boiling water sound.

[0007] A boiling water sound is generated according to the above principle, and the magnitude thereof is proportional to the magnitude of the vibration energy. The higher the temperature in the bubble generated at the time of the boiling water, the sharper it disappears, and the larger the bubble, the larger the amplitude. The vibration energy increases. In the conventional winding type heating element shape, the heating wires 108 are wound around the substrate 107 at equal intervals while securing an insulation distance within a certain range, or a metal foil heating element is formed in a certain foil width shape. 5, the central portion 108 in FIGS.
a and 109a and both outer portions 108b and 109b
, The temperature of the central portions 108a and 109a increases.

Accordingly, the heat distribution of the heat transfer plate 106 becomes non-uniform, and the heat generation capacity (watt) must be reduced in order to reduce the boiling water noise. Occurs. In order to reduce the vibration at the bottom of the container, a solution such as increasing the thickness of the heat transfer plate has been taken. However, in this case, a problem such as an increase in cost arises.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has as its first object to reduce the boiling water noise by forming a plurality of projections on the bottom surface of a container.

A second object of the present invention is to integrate the heat generating element provided on the bottom of the container of the electric water heater into a compact body and to reduce the sound of the water heater.

It is a third object of the present invention to reduce the boiling water sound without prolonging the water heating time.

It is a fourth object of the present invention to further reduce the boiling water sound by synergistic effect by forming the protruding portions formed on the heat transfer plate between the bands (heating portions) of the metal foil heating element. .

[0013]

According to a first aspect of the present invention, there is provided an electric device comprising a plurality of projections formed on a bottom surface of a container for storing a liquid. Use a water heater.

In order to achieve the second object, the second object of the present invention
Means comprises a container for storing a liquid, and a heat generating structure formed by sandwiching and fixing a heat generating element located on the bottom surface of the container and covered with an insulating material by a heat transfer plate and a seam plate. An electric water heater characterized in that a plurality of protrusions are formed on the electric water heater.

In order to achieve a third object, a third aspect of the present invention is provided.
Means, in addition to the second means, the heating element is a metal foil heating element in which the heating element is continuously formed in a meandering strip shape and the width of the meandering outer portions is narrower than the other. And

In order to achieve a fourth object, a fourth object of the present invention is provided.
The means of the invention is characterized in that, in addition to the third means, the projecting portion of the heat transfer plate forming the heat generating structure is located vertically above and between the strips of the metal foil heating element.

[0017]

According to the present invention, a plurality of projections are formed on the heat transfer plate to provide rigidity to the heat transfer plate to suppress the energy due to the vibration of the liquid and to change the electric resistance, thereby providing a flat surface. As a result, the heat generation of the heating element can be made uniform, and the heat generation of the heat transfer plate for heating the liquid in the container can be made uniform.

Further, by effectively using the area of the heat transfer plate, it is possible to lower the maximum temperature on the heat transfer plate in the case of the same electric heat capacity (watt) as the conventional configuration. In addition, heat can be efficiently transmitted to the heat transfer plate by arranging a plurality of protrusions on the heat transfer plate between the bands (heat generating portions) of the metal foil heating element.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a heat generating structure of an electric water heater according to the present invention. Reference numeral 1 denotes a container for accommodating a liquid provided in an electric water heater main body. The heat plate 2 is integrally formed, and the heat generating element 4 is disposed on the back surface of the heat transfer plate 2 via the insulator 3 vertically, and the heat generated by the heat generating element 4 is efficiently radiated to the liquid in the container 1. Therefore, the seam plate 6 is welded and fixed to the heat transfer plate 2 and the bottom surface of the container 1 via the heat diffusion plate 5 having good thermal conductivity so as to sandwich and fix the heating element 4.

By providing a plurality of protrusions on the bottom surface of the container in this manner, the boiling water noise can be reduced without reducing the heat generation capacity (watt). In addition, the heat transfer plate has rigidity to suppress the energy due to the vibration of the liquid, and by changing the electric resistance, the heat generated by the heating element can be made uniform on a flat surface, thereby heating the liquid in the container. The heat generation of the heat transfer plate can be made uniform.

FIG. 2 is a partially enlarged perspective view of the bottom of the container of the electric water heater of the present invention. In addition to the shape having a plurality of dimple-shaped protrusions as shown in FIG. The same effect can be obtained even with a shape having a rib-shaped protrusion as shown in FIG.

Next, FIG. 3 shows an embodiment for further reducing the boiling water sound. FIG. 3 is a cross-sectional view of a main part of the heat transfer plate of the electric water heater of the present invention, wherein the heating element is disposed above and below a band 8 of the metal foil heating element with an insulator 3 interposed therebetween. The protruding portion 7 is disposed so as to be located vertically above the band of the metal foil heating element.

As shown in FIG. 4, the metal foil heating element 8 is formed so that both outer portions C meandering in a band shape are narrower than the band width of the central portion D.

[0024] By positioning the protruding portion of the heat transfer plate forming the heating structure vertically above and between the strips of the metal foil heating element, it is possible to more effectively reduce the boiling water noise. The heat generated by the heating element can be efficiently transmitted to the heat transfer plate.

[0025]

As is apparent from the above description of the embodiment, by forming the protrusions on the heat transfer plate and having rigidity, the disappearance and rupture of bubbles generated at the time of boiling water resonate outside the water heater main body. By making the outer sides of the metal foil heating element meandering in a strip shape narrower than the central band width, heat transfer can be achieved with the same heating capacity (watt) compared to the conventional heating element configuration. The temperature on the plate can be lowered, and an electric water heater having a low boiling water sound can be provided. Conversely, it is possible to increase the electric heat capacity (watt) as in the case of the conventional water heater sound and shorten the water heater time.

Further, heat conduction is impaired in the space of the heating element caused by forming the projecting portion of the heat transfer plate. This is because the projecting portion of the heat transfer plate is located between the bands of the metal foil heating element. The electric water heater equipped with an easy-to-use electric heating element can reduce the vibration energy due to bubbles generated at the time of water heating, and increase the cost without increasing the cost. It can be provided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a heat generating structure of an electric water heater according to the present invention.

FIG. 2A is a perspective view of a main part of a bottom surface of a container of the electric water heater of the present invention. FIG. 2B is a perspective view of a main part showing another embodiment of the bottom surface of the container of the electric water heater.

FIG. 3 is a partial sectional view of a heating element structure of the electric water heater of the present invention.

FIG. 4 is a plan view of a metal foil heating element of the electric kettle of the present invention.

FIG. 5 is a cross-sectional view of a main part of a bottom portion of a container having a heating element configuration of a conventional electric water heater.

FIG. 6 is a plan view of a conventional wound heater of an electric water heater.

FIG. 7 is a plan view of a metal foil heating element of a conventional electric water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Heat transfer plate 3 Insulating plate 4 Heating element 5 Heat diffusion plate 6 Seam plate 7 Projection 8 Metal foil heating element band

Continuation of the front page (56) References JP-A-7-16154 (JP, A) JP-A-6-237861 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A47J 27 / 21 101

Claims (4)

(57) [Claims] 1. An electric water heater, wherein a plurality of protrusions are formed on a bottom surface of a container for storing a liquid. 2. A heat transfer structure comprising: a container for accommodating a liquid; and a heat generating structure formed by sandwiching and fixing a heat generator located on the bottom of the container and covered with an insulating material by a heat transfer plate and a seam plate. An electric water heater comprising a plurality of projections formed on a plate. 3. The heat generating element is a metal foil heat generating element which is continuously formed in a meandering manner in a belt shape and has a narrower band width on both outer side portions than the other. 2. The electric kettle according to 2. 4. The electric water heater according to claim 3, wherein the protruding portion of the heat transfer plate forming the heat generating structure is located vertically above and between the bands of the metal foil heat generating element.