JP2001000324A - Electric water boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat insulating performance by reducing the heat conductivity of a vacuum heat insulator. SOLUTION: This electric water boiler is provided with vacuum heat insulating material 11 formed by filling heat insulating core material 13 in wrapping bag material formed of a laminated film 14 with a gas barrier layer 16 and evacuating, and the gas barrier layer 16 constituting the vacuum heat insulating material 11 is provided with evaporation layer heat insulating material. In this case, by providing the gas barrier layer 16 constituting the vacuum heat insulating material 11 with an evaporation layer, the heat insulating performance of the electric water boiler is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater for supplying hot water for drinking at home or office.

[0002]

2. Description of the Related Art In an electric water heater, water is heated using electric power, and the water is kept at a constant temperature for a long time. To reduce the input power for the heating, the inside of the water storage container is covered with various heat insulating materials. There are organic heat insulating materials such as urethane, inorganic heat insulating materials such as glass wool and ceramic wool, and heat insulating materials using metal reflectors. Further, a vacuum heat insulating material is used in which a heat insulating core material is sealed in a packaging material made of a laminated film using an aluminum foil as a gas barrier layer, and the inside of the packaging material is evacuated.

[0003]

However, since organic insulation materials such as urethane are significantly deteriorated by heat,
There was a problem that the heat insulating performance of the heat insulating material was reduced at a temperature around 100 ° C. in the electric water heater. Further, although inorganic heat insulating materials have excellent durability against heat, there is a problem that the heat insulating performance is generally low. In addition, a vacuum heat insulating material in which the inside of the packing material is evacuated has good heat insulating performance inside the packing material, but has heat conduction through the aluminum foil of the gas barrier layer constituting the packing material. Not good enough.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an electric water heater in which heat conduction through a gas barrier layer is reduced as much as possible to improve the heat insulating performance of a vacuum heat insulating material. I do.

[0005]

According to the present invention, a gas barrier layer in a laminated film constituting a vacuum heat insulating material is formed by a vapor deposition method.
By forming the gas barrier layer by a vapor deposition method, the layer thickness can be reduced as compared with a foil-like gas barrier layer obtained by stretching a metal. Further, it is possible to select a material having a lower thermal conductivity than aluminum as a deposition material at the same time. As described above, by forming by a vapor deposition method, a gas barrier layer can be formed by reducing a layer thickness or selecting a vapor deposition material with a material having a small thermal conductivity. As a result, heat conduction through the gas barrier layer is reduced, and an electric water heater having improved heat insulation performance of the entire vacuum heat insulating material can be obtained.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS To solve the above-mentioned problems, the present invention provides a water storage container, a heater for heating water in the water storage container, a hot water outlet path for discharging the heated water, and a gas barrier layer. And a vacuum heat insulating material that is evacuated by enclosing a heat insulating core material in a packaging material made of a laminated film having the following characteristics. The gas barrier layer constituting the vacuum heat insulating material is a vapor-deposited layer.

The above-mentioned deposited layer is formed by depositing a metal, and as the deposited metal, at least one of aluminum, titanium and nickel is used.

The foil thickness of an aluminum foil conventionally used as a gas barrier layer is about 6 to 10 μm. The thermal conductivity of aluminum has an average temperature of 300K.
Is 237 W / m · K. On the other hand, when the gas barrier layer is formed by a vapor deposition method, the layer thickness can be formed to 0.01 to 0.3 μm. Therefore, by using the vapor deposition method, the layer thickness can be reduced by 20 times or more as compared with the conventional one. Further, by using titanium or nickel as the deposition material, the thermal conductivity can be reduced. As a result, heat conduction through the gas barrier layer can be reduced, and the heat insulating performance of the entire vacuum heat insulating material can be improved.

The above-mentioned vapor deposition layer is obtained by vapor-depositing a metal oxide.
At least one of silicon oxide and aluminum oxide is used.

The thermal conductivity of a metal oxide is generally lower than that of the metal alone. Therefore, a metal oxide gas barrier layer is better if it can be deposited in an oxide state and has gas barrier properties. Silicon oxide and aluminum oxide are optimal in this regard, and have extremely low thermal conductivity. Therefore, heat conduction of the metal oxide through the gas barrier layer is small, so that the heat insulating performance of the entire vacuum heat insulating material can be improved.

The present invention also provides a water storage container, a heater for heating water in the water storage container, a hot water outlet path for discharging the heated water, and a heat insulating core in a packaging material comprising a laminated film having a gas barrier layer. An electric water heater having a vacuum heat insulating material in which the material is sealed and evacuated, wherein one of the gas barrier layers in the laminated film forming the vacuum heat insulating material is a metal foil layer, and the other is a vapor deposition layer. Then, the metal foil layer surface is arranged on the high-temperature container side, and the sealing portion of the packaging material is bent toward the high-temperature side.

The metal foil is any one of an aluminum foil, a stainless steel foil and an iron foil, and the metal layer is a metal or a metal oxide.

By setting the metal foil layer surface of the vacuum heat insulating material on the side of the high-temperature container in this way, it is possible to prevent thermal deterioration of the gas barrier layer. Further, by bending the seal portion toward the high-temperature container side, the heat transmitted through the metal foil and escaping to the outside can be suppressed.

[0014]

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

(Embodiment 1) In FIG. 1, reference numeral 1 denotes a main body (hereinafter referred to as a main body) of an electric water heater, and a water storage container 2 having an inner diameter of 184 mm and a depth of 250 mm for storing hot water therein (hereinafter referred to as a container 2). have. Reference numeral 3 denotes an upper cover that covers the upper part of the main body 1 so as to be openable and closable. Reference numeral 4 denotes a vapor passage provided in the upper lid, one end of which passes through the inner plug 5 and communicates with the inside of the container 2, and the other end communicates with the atmosphere. Reference numeral 6 denotes a drive pump provided at the bottom between the main body 1 and the container 2, and its suction port 7 communicates with the bottom of the container 2. 8 is a tap hole,
From here the hot water is taken out of the electric kettle. Reference numeral 9 denotes a heater for heating.
It is attached to the lower part of. Reference numeral 10 denotes a temperature detector, which is attached to the lower part of the container 2 and the center of the heater 9. 11
Is a vacuum heat insulating material wound on the side surface of the container 2, and has a role of suppressing heat of the container 2 from escaping from the side surface of the main body 1.

Next, the vacuum heat insulating material 11 used here is shown in FIG.
Will be described. FIG. 2 shows a sectional view of the vacuum heat insulating material 11. 13 is a core material of a vacuum heat insulating material. Laminated film 14
Is composed of a seal layer 15, a gas barrier layer 16, and a protective layer 17, and the protective layer 17 is composed of a polyethylene terephthalate layer. The core material 13 used synthetic silica. Since the particles of synthetic silica are very fine, the thermal conductivity of the particles is very low. Furthermore, if the pressure is 10 torr or less, the material exhibits a very small thermal conductivity regardless of the pressure. Therefore, it is a very suitable material under the condition that the molecular motion of air is high at a high temperature. The seal layer 15 uses unstretched polypropylene. As the gas barrier layer 16, a vapor deposition layer obtained by vapor deposition using polyethylene terephthalate as a support was used. Polyethylene terephthalate was used as the protective layer 17 having a role of protecting the seal layer 15 and the gas barrier layer 16. Polyethylene terephthalate has excellent heat resistance and is suitable as a protective layer for an electric water heater.

The mounting form of the vacuum heat insulating material 11 used here will be described with reference to FIG. Reference numeral 18 denotes a portion having the core material 13 and having a heat insulating property as a vacuum heat insulating material. Reference numeral 19 denotes a heat seal portion, which is a portion where the seal layer 15 is thermally welded, and does not include a core material. Vacuum insulation 1
Numeral 1 has a rectangular shape, and when wound around the container 2, the heat seal portion 19 is bent outward as shown in FIG. In this case, the heat seal portion does not come into direct contact with the high temperature side, and the durability deterioration is reduced.

The operation of this embodiment will be described below. When electricity is supplied after water is put into the container 2, the temperature of the water in the container 2 is measured by the temperature detector 10 and a signal thereof is sent to the control device 12,
The control device starts to energize the heater 9. When the water in the container 2 boils, the energization of the heater 9 ends. Thereafter, upon receiving a signal from the temperature detector 10, the controller 1
Numeral 2 controls the heater 9 so that the temperature of the container 2 becomes constant.

(Experimental Example 1) As a gas barrier layer of the vacuum heat insulating material used in the above-mentioned electric water heater, a total of 6 aluminum vapor deposition layers, titanium vapor deposition layers, nickel vapor deposition layers, aluminum oxide vapor deposition layers, silicon oxide vapor deposition layers, and aluminum foils were used.
Available in different types. Polyethylene terephthalate was used as a support, and a vapor deposition layer was formed so as to have a thickness of about 0.05 μm using a quartz crystal film thickness meter.

Water was placed in an electric kettle equipped with a vacuum heat insulating material using these vapor-deposited layers as gas barrier layers, and the heat retention power at the initial stage and after 1000 hours of use was measured. The temperature of the heat retaining water is 97 ° C., and the ambient temperature is 20 ° C. The measurement was performed after a sufficient equilibrium state was reached. Further, for comparison with the conventional case, the same experiment was performed on a vacuum heat insulating material using an aluminum foil for the gas barrier layer.

The results of the measurement of the insulation power are shown in Table 1.

[0022]

[Table 1]

As described above, when the gas barrier layer of the vacuum heat insulating material is formed by the vapor deposition method, the heat retention power can be suppressed lower than that of the conventional vacuum heat insulating material using aluminum foil. Further, among them, a tendency using a metal oxide was found to be better. By using a vacuum heat insulating material for the gas barrier layer formed by the vapor deposition method as described above,
An electric water heater with low heat retention power can be realized.

(Embodiment 2) The structure of the electric water heater 1 used in this embodiment and the operation of the embodiment are the same as those of the embodiment 1.

Next, the vacuum heat insulating material 11 used here is shown in FIG.
Will be described. The laminated film 14 is composed of a seal layer 15, a gas barrier layer 16, and a protective layer 17, and a core material is sealed as in the first embodiment. However, in this embodiment,
One of the gas barrier layers 16 is a deposition layer formed by vapor deposition using polyethylene terephthalate as a support, and the other is a metal foil.

The mounting of the vacuum heat insulating material 11 will be described with reference to FIG. Reference numeral 18 denotes a portion having the core material 13 and having a heat insulating property as a vacuum heat insulating material. Reference numeral 19 denotes a heat seal portion, which is a portion where the seal layer 15 is thermally welded, and does not include a core material. The vacuum heat insulating material 11 has a rectangular shape, and when it is wound around the container 2, it is mounted on the container side with the gas barrier layer made of metal foil. This can prevent the gas barrier layer from deteriorating due to heat. Further, the heat seal portion 19 is bent inwardly as shown in FIG. By doing so, it is possible to prevent the heat transmitted through the metal foil from escaping.

(Experimental Example 2) A silicon oxide vapor-deposited layer was used as one gas barrier layer and an aluminum foil was used as the other gas barrier layer of the vacuum heat insulating material used in the above-described electric water heater. Polyethylene terephthalate was used as a support for the silicon oxide vapor-deposited layer, and the vapor-deposited layer was formed to have a thickness of about 0.05 μm using a quartz-type film thickness meter.

The thickness of the aluminum foil is 6 μm. These vapor-deposited layers and a metal foil layer were laminated to form a gas barrier layer. Water was placed in an electric kettle equipped with a vacuum heat insulating material having the metal foil layer on the container side and the seal layer bent on the container side, and the heat retention power at the initial stage and after 1000 hours of use was measured. The temperature of the heat retaining water is 97 ° C., and the ambient temperature is 20 ° C. The measurement was performed after a sufficient equilibrium state was reached. For comparison, the same experiment was performed when the deposition layer side was the container side and when the sealing layer was bent outward as shown in FIG.

Table 2 shows the measurement results of the heat retention power.

[0030]

[Table 2]

As described above, the configuration in which the vapor-deposited layer of the vacuum heat insulating material is on the container side and the seal layer is bent on the container side is the best in both the initial heat retention power and the heat retention power after 1000 hours. The good initial heat retention power is because the layer in contact with the folded seal portion and the high-temperature container is a vapor-deposited layer, so that heat transfer is suppressed as compared with the case of a metal layer. In addition, the reason why the heat retention power after 1000 hours is good is that the metal barrier surface is disposed on the high-temperature container side, so that thermal deterioration of the gas barrier layer can be prevented. In this way, the heat conduction to the outside can be reduced by bending the deposition surface to the outside and bending the sheet portion to the inside. as a result,
An electric water heater having a low heat retention power for a long time can be realized.

[0032]

As is apparent from the above embodiment, according to the first to third aspects of the present invention, the layer thickness can be reduced, so that heat transfer can be reduced, and the heat insulation of the entire vacuum heat insulating material can be reduced. Performance can be improved. Therefore, according to the fourth and fifth aspects of the present invention, not only can the layer thickness be reduced, but also the thermal conductivity itself can be reduced, so that the heat insulating performance of the entire vacuum heat insulating material is further improved. be able to.

According to the sixth and seventh aspects of the present invention,
Since the heat deterioration of the gas barrier layer can be prevented and the heat escaping to the outside can be suppressed, the heat insulating performance of the entire vacuum heat insulating material can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electric water heater in embodiments 1 and 2 of the present invention.

FIG. 2 is a cross-sectional view of a vacuum heat insulating material according to the first and second embodiments of the present invention.

FIG. 3 is a cylindrical view of the vacuum heat insulating material according to the first embodiment of the present invention.

FIG. 4 is a cylindrical view of a vacuum heat insulating material according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Electric water heater main body 2 Water storage container 3 Upper lid 4 Steam passage 5 Inner plug 6 Drive pump 7 Suction port 8 Hot water outlet 9 Heater 10 Temperature detector 11 Vacuum insulation material 12 Control device 13 Core material 14 Laminated film 15 Seal layer 16 Gas barrier Layer 17 Protective layer

Claims (7)

[Claims] 1. A heat insulating core material is enclosed in a packaging material comprising a laminated film having a water storage container, a heater for heating water in the water storage container, a hot water outlet path for discharging the heated water, and a gas barrier layer. And a vacuum heat insulating material evacuated and evacuated, wherein the gas barrier layer constituting the vacuum heat insulating material is a vapor-deposited layer. 2. The electric water heater according to claim 1, wherein a metal is deposited as the deposition layer. (3) aluminum, titanium,
3. The electric water heater according to claim 2, wherein at least one of nickel is used. 4. The electric water heater according to claim 1, wherein a metal oxide is deposited as a deposition layer. 5. The electric water heater according to claim 4, wherein at least one of silicon oxide and aluminum oxide is used as the metal oxide to be deposited. 6. A heat insulating core material is enclosed in a packaging material comprising a laminated film having a water storage container, a heater for heating water in the water storage container, a hot water discharge path for discharging the heated water, and a gas barrier layer. And a vacuum heat insulating material evacuated and evacuated, wherein one of the gas barrier layers in the laminated film constituting the vacuum heat insulating material is a metal foil layer and the other is a vapor deposition layer, and the high temperature container side An electric water heater in which a metal foil layer surface is disposed on a surface and a sealing portion of the packaging material is bent toward a high temperature side. 7. The electric water heater according to claim 6, wherein any one of an aluminum foil, a stainless steel foil, and an iron foil is used as the metal foil, and any one of a metal and a metal oxide is deposited as a deposition layer.