JP2006043023A - Heat restraining tub and electric kettle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat restraining tub and an electric kettle having an energy saving property which is high for a long period by improving the heat insulation material of an inner container. <P>SOLUTION: By applying the vacuum insulation material 1 of small heat leakage through the outline of the insulation material to the heat restraining tub and the electric kettle, covering the periphery of a lid 7 and covering a direction lower than the inner container 2 further, a larger heat insulation effect is obtained while suppressing the heat leakage through the outline of the insulation material. Also, by providing a polyacrylic acid based resin layer adjacently to the vapor deposition layer of the outer bag of the vacuum insulation material 1, the temporal degradation of heat conductivity is reduced even when the vapor deposition layer is set as one layer and the heat leakage through the outline of the vacuum insulation material 1 is reduced further. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat insulating tank and an electric water heater equipped with a vacuum heat insulating material.

  Conventionally, this type of thermal insulation tank and electric water heater have a vacuum heat insulating material installed outside the inner container, and as a result, the amount of heat leaking from the inner container is reduced, and a high energy saving effect is achieved. There are hot water storage containers, water heaters, rice cookers, and heat cookers in heat insulation tanks, but electric water heaters can be used to keep water at a certain temperature by adding water and connecting the power source. In addition to these applications, it is used for various purposes such as hot water for infants' milk. At that time, since it is necessary to keep hot water for a long time, various heat insulating materials have been used.

  For example, there are organic heat insulating materials such as urethane, inorganic heat insulating materials such as glass wool and ceramic wool, those using a metal reflector, and those provided with a vacuum heat insulating material (see Patent Document 1).

  FIG. 6 shows a conventional electric water heater described in Patent Document 1. In FIG. As shown in FIG. 6, the machine body 101 constituting the outer portion, a container 103 for storing an object 102 such as water, and a core material 112 and an outer bag 113 attached around the container 103, and the inside It is comprised from the vacuum heat insulating material 111 obtained by decompressing, and the heating means 106 installed in the outer bottom face part of the container 103. FIG.

  In the electric water heater configured as described above, the object 102 is heated and kept at a constant temperature by the heating means 106, and during the heat keeping, heat radiation from the side surface of the container 103 is suppressed by the vacuum heat insulating material 111 and the amount of energy at the time of the heat keeping is kept. Was reduced.

  Furthermore, among the vacuum heat insulating materials applied in this way, there is one in which a vapor deposition layer based on an ethylene vinyl alcohol copolymer film having a high gas barrier property is provided on the gas barrier layer of the outer bag.

  This can reduce heat leakage through the film more than the vacuum heat insulating material using a metal foil for the conventional gas barrier layer, and the higher gas barrier property of the ethylene vinyl alcohol copolymer film than the conventional vapor deposited film. Some have reduced long-term deterioration in thermal conductivity due to gas intrusion into the glass and ensure long-term energy saving (see Patent Document 2). Moreover, there exists what provided the vacuum double container which consists of metals around the inner container (refer patent document 3).

  FIG. 7 shows a conventional electric water heater described in Patent Document 3. As shown in FIG. As shown in FIG. 7, an electric water heater is provided that houses an exterior body 201 that constitutes an outer portion and an inner container 207 to which a hot water heating function is added, and has a heat retaining means that surrounds the inner container 207. The heat retaining means is constituted by a vacuum heat insulating material double jacket, the vacuum double jacket 218 is disposed between the outer body 201 and the inner container 207, and a predetermined gap is provided between the vacuum double jacket 218 and the inner container 207. It was set as the structure which provided the clearance gap.

  In the electric water heater configured as described above, the object to be stored is heated and kept at a constant temperature by the heater 213, and during the heat keeping, heat radiation from the side surface of the inner container 207 is suppressed by the vacuum double jacket 218, and the amount of energy at the time of keeping warm. Was reduced.

Further, the vacuum double jacket 218 is arranged so as to cover the position lower than the bottom of the inner container 207 in the height direction, or the inner container 207 and the lid packing 211 are engaged in the height direction. The structure which has arrange | positioned so that it may cover to a position higher than the seal | sticker part to perform can be taken, and it had the further heat leak prevention effect.
JP-A-11-290210 JP 2001-231681 A JP 2000-316720 A

  However, when an organic heat insulating material such as urethane is used, the temperature of the electric water heater is raised to 100 ° C., so that the heat insulating material is deteriorated and the heat insulating performance is extremely deteriorated.

  In addition, although the inorganic heat insulating material is excellent in heat resistance and durability, there are problems such as poor heat insulating performance and that fine fibers are easily generated from the surface and scattered to the surroundings, resulting in poor handling.

  As means for solving such problems, a silica gel or inorganic fiber is used as a core material, and it is packaged in an outer bag with a laminated structure having a gas barrier property, and a vacuum heat insulating material obtained by sealing the inside under reduced pressure is provided. There is.

  In the structure of the above-mentioned Patent Document 1, since the heat insulation performance is reduced over time and the use of a vacuum heat insulating material with low thermal conductivity, a high heat insulating effect can be obtained over the long term. Reduced power consumption. However, since the metal foil is used as the outer bag of the vacuum heat insulating material, heat leaks from the inner container to the outer container through the metal foil. Moreover, in the vacuum heat insulating material which uses the vapor deposition film with small heat conductivity for an outer bag, since the gas barrier property is inferior compared with the time of metal foil use, deterioration with time of heat conductivity has increased. In addition, there is a problem that heat leakage is extremely large at the lid, the side surface of the opening, and the periphery of the bottom, which are places where no vacuum heat insulating material exists, which hinders improvement in energy saving performance.

  In view of this, there is one in which a metal film layer is not provided on the outer bag and a vapor deposition film based on an ethylene vinyl alcohol copolymer film having a high gas barrier property is applied. Thereby, while reducing the heat leak by an outer bag, the fall of the gas barrier property of a vacuum heat insulating material was able to be reduced rather than the time of application of the conventional vapor deposition film.

  However, in the conventional configuration, it is necessary to provide two vapor deposition layers in order to maintain the thermal conductivity for a longer period. In addition, similar to Patent Document 1, there is a problem that heat leakage is very large at the lid, the side surface of the opening, the bottom, and the like where there is no vacuum heat insulating material, which hinders improvement in energy saving performance. It was.

  Therefore, in the configuration of Patent Document 3 above, the vacuum double jacket made of a metal container is disposed long in the upward and downward directions of the inner container, so that heat leakage of the flange portion that is the joint between the lid and the inner container is conventionally caused. In addition, the periphery of the heating means installed around the bottom of the inner container is covered with a heat insulating material to prevent leakage of heat from the heating means toward the exterior body. As a result, the heat insulation is improved, and the inner container can be effectively heated, so that an energy saving improvement effect is obtained.

  However, although the heat conductivity inside the vacuum double jacket is kept very good, the outer portion of the vacuum double jacket made of metal is very high in heat conductivity, so the heat leakage through the outer shell is large. Had problems. Moreover, the vacuum double jacket made of metal is heavy, and when it is mounted on an electric water heater, there is a problem that the total weight is larger than when other heat insulating materials are used, and the usability when carrying is poor.

  The present invention solves the above-described conventional problems, and has an object to provide a heat-insulating tank and an electric water heater that have good heat insulating properties and are less susceptible to deterioration of heat insulating performance over time and are easy to use. .

  In order to solve the above-mentioned conventional problems, the present invention surrounds the inner container side surface and covers at least a part of the side surface of the lid body with a vacuum heat insulating material which is composed of at least a core material and an outer bag and whose inside is decompressed. A film having a vapor deposition layer on the outer bag was used. Thereby, it is possible to cover not only the side surface of the inner container but also the heating means installed around the flange portion where the lid and the inner container are engaged or outside the bottom of the inner container.

  Conventionally, in a heat insulating tank and an electric water heater using a vacuum tube composed of a metal double container as a heat insulating material, the heat conduction through the outer shell of the heat insulating material is large because the heat conduction of the outer wall of the vacuum tube is extremely high, and the heat insulating material Was inhibiting the warming effect. Since the outer shell of the vacuum heat insulating material is composed of an outer bag having a small heat conduction, heat leakage through the heat insulating material outer shell is greatly reduced as compared with the conventional case, and as a result, an effect of improving the heat retaining property is obtained.

  In general, the convective heat moves upward, so the convective heat of the air layer inside the inner container travels toward the lid / flange and leaks to the outside by heat conduction after reaching the inside of the lid and the flange. To go.

  Conventionally, particularly in an electric water heater, a foam-type heat insulating material having a thickness of about several centimeters has been inserted into a lid to suppress heat conduction. On the other hand, since the flange part is made of a resin material with low heat insulation, the heat conduction in the direction of the outer container is larger than that of the lid part, and the heat conduction conducts heat to the surrounding air, and between the outer container and the inner container. It caused convective heat transfer. As a result, heat is leaked to the outside of the heat insulating tank or the electric water heater, resulting in a decrease in heat retention. Therefore, by covering the periphery of the flange portion with a vacuum heat insulating material having high heat insulating performance, movement of heat transmitted from the flange portion resin and the surrounding air toward the outer container can be suppressed.

  Further, when the power is turned on, heat is generated by the heating means and is transmitted toward the inner container to warm the inside. At the same time, heat is also transmitted to the air around the heating means. Conventionally, there is no heat insulating material around the heating means, so convective heat moves toward the outer container and leaks to the outside by conduction from the inner surface of the outer container. Therefore, by covering the surroundings of the heating means with a vacuum heat insulating material having high heat insulating performance, heat conduction of convective heat around the heating means is suppressed by the vacuum heat insulating material. Moreover, since the convection range of the air layer is narrowed and most of the convection heat moves toward the bottom of the inner container, the heat retention of the inner container is further improved.

  From the above, the heat retaining properties of the heat retaining tank and the electric water heater are greatly improved.

  The heat insulating tank and electric water heater of the present invention have a large effect of reducing heat leakage from the heat-insulated material and heat leakage through the outer shell of the heat insulating material by increasing the coverage of the vacuum heat insulating material. It is possible to insulate or warm the object to be insulated with less energy.

  In addition, since it is possible to reduce the deterioration of the thermal conductivity of the vacuum heat insulating material over time compared to the case of applying the conventional vapor deposition film, it is possible to maintain the energy saving performance of the heat insulation tank and the electric water heater for a long time. Since it becomes lighter than the above, the usability of the heat insulating tank and the electric water heater is improved.

  The invention of the heat insulating layer according to claim 1 is a vacuum that surrounds at least the outer container, a bottomed inner container accommodated in the outer container, a lid that covers the upper part of the outer container, and the side surface of the inner container. In the heat insulating tank having a heat insulating material, the vacuum heat insulating material is composed of at least a core material and an outer bag, and the inside is decompressed, and is disposed so as to cover at least a part of the side surface of the lid, The outer bag is made of a film having a vapor deposition layer.

  Thereby, since the heat conduction of the heat insulating material outer shell is reduced as compared with a vacuum tube made of a conventional metal container, the amount of heat leaked through the heat insulating material outer shell is reduced.

  Moreover, since a vacuum heat insulating material coat | covers a part of circumference | surroundings of a lid | cover, the circumference | surroundings of a flange can be insulated, Therefore It becomes possible to prevent the heat | fever leaking from a flange. Therefore, heat retention is improved and an energy saving effect is obtained.

  Further, since the vacuum heat insulating material is lighter than a conventional vacuum double jacket made of metal, an effect of facilitating transportation and carrying can be obtained.

  Note that the vacuum heat insulating material is a material in which a dry silica powder, carbon powder, inorganic fiber alone or a mixture thereof is solidified or filled into a nonwoven fabric, or a laminate of inorganic fibers in a sheet shape, etc. Use a film with at least gas barrier properties and heat-sealability for the outer bag, but both the inorganic material and the organic material can be used if both the core material and the outer bag have heat resistance at the operating temperature. Not specified.

  By applying the vacuum heat insulating material as described above, the heat retaining property is improved, so that the heat retaining object can be kept warm with less energy than conventional.

  The invention of the heat insulating layer described in claim 2 is the one in which the lower end portion of the vacuum heat insulating material in the invention of claim 1 is arranged longer in the downward direction than the inner container. Since it becomes possible to block the leakage of the generated heat toward the outer container, the heat retention is improved. In addition, since the heated air molecules convection in the upward direction, the heat blocked from leaking by the vacuum heat insulating material is transferred toward the inner container, so that the heating efficiency of the heat retaining tank and the electric water heater is improved. As a result, a higher energy saving effect can be obtained.

  The invention of the heat retaining layer described in claim 3 is the invention according to claim 1 or 2, wherein at least a part of the outer bag at a location where the core material does not exist is bent toward the outer container side. Thus, the heat-sealed portion of the outer bag is placed in a low-temperature environment as compared with the case where bending is not performed or the fin is bent inward.

  Since the amount of gas entering from the seal portion with time increases in proportion to the temperature rise, the amount of intrusion gas is greatly reduced as compared with the case where bending is not performed or the fin is bent inward. Therefore, since the increase in the internal pressure of the vacuum heat insulating material is prevented, deterioration with time of the thermal conductivity can be reduced.

  Moreover, since the effective area of a heat insulating material increases by bending a fin, a heat insulating material can be effectively arrange | positioned with respect to a heat retention target object.

  By applying the vacuum heat insulating material as described above, it becomes possible to maintain the energy saving performance of the heat retaining tank and the electric water heater for a long period of time, and the effect of improving the energy saving performance can be obtained.

  The invention of the heat insulating layer according to claim 4 is the invention according to any one of claims 1 to 3, wherein the outer bag of the vacuum heat insulating material forms a laminate structure, and at least a polyacrylic adjacent to the vapor deposition layer. It has an acid resin layer.

  The polyacrylic acid resin layer itself has a high gas barrier property, but by providing this on the upper layer of the vapor deposition layer, the polyacrylic acid molecules serve to compensate for defects between the molecules of the vapor deposition layer. The gas barrier properties are much improved compared to the case of using a single layer. Furthermore, since the polyacrylic acid resin layer has a very flexible property, no cracks are generated even when the vacuum heat insulating material is processed into a cylinder, and the gas barrier property when a crack occurs in the vapor deposition layer. The decrease can be reduced as compared with the conventional case. In addition, since the polyacrylic acid resin layer is extremely excellent in heat resistance, there is almost no deterioration during heat fusion.

  The laminate structure of the outer bag is not particularly specified, and has at least a polyacrylic acid resin layer adjacent to the vapor deposition layer, a film serving as a base material for the vapor deposition layer, and a heat-sealing layer, and has a heat resistance within the operating temperature range. Any configuration may be used as long as it has the characteristics. It is also possible to provide a protective layer on the surface for enhancing pinhole resistance and preventing wear.

  The invention of the heat insulating layer described in claim 5 is configured such that the polyacrylic acid-based resin layer in the invention described in claim 4 is inside the vapor deposition layer. As a result, the distance between the polyacrylic resin layers sandwiching the heat-sealing layer in the cross section of the seal layer of the vacuum heat insulating material is reduced, so that intrusion of gas and moisture can be reduced, and the internal pressure of the vacuum heat insulating material can be reduced. Can be prevented from rising.

  In addition, since the vapor deposition layer and the polyacrylic acid resin layer hinder the penetration of moisture contained in the base film into the vacuum insulation material, the effect of outgassing even when a highly hygroscopic resin is used for the base film Therefore, it is possible to prevent an increase in the initial internal pressure of the vacuum heat insulating material.

  Therefore, it is possible to prevent the deterioration of the thermal conductivity of the vacuum heat insulating material over time and the deterioration of the initial performance of the vacuum heat insulating material due to the moisture absorption of the film. Can be maintained, and deterioration of the initial energy saving performance can be prevented.

  The invention of the heat insulating layer according to claim 6 is the invention according to claim 4 or 5, wherein the vapor deposition layer of the outer bag is a single layer. Conventionally, in order to strengthen the gas barrier property of the outer bag, the gas barrier layer is often used by laminating two vapor-deposited layers, but by providing a polyacrylic acid resin layer having a high gas barrier property on the vapor-deposited layer. Since the polyacrylic acid molecule functions to compensate for defects between molecules in the vapor deposition layer, the gas barrier property is improved far more than when each is used as a single layer.

  Therefore, even when the vapor deposition layer is a single layer, the reliability over time can be sufficiently maintained. Thereby, since the thickness of the vapor deposition layer used for the laminated film of the outer bag can be reduced as compared with the conventional case, the heat conduction of the outer bag is reduced, leakage through the outer bag surface is reduced, Electric water heaters can save energy and reduce costs.

  The invention of the electric water heater according to claim 7 is the electric water heater provided with the heat insulating tank according to any one of claims 1 to 6, and thereby effectively insulates the object to be kept inside the inner container. However, since it is possible to reduce the deterioration over time of the vacuum heat insulating material, the electric water heater can exhibit high energy saving performance for a long time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows a cross-sectional view of an electric water heater provided with a heat retaining tank in Embodiment 1 of the present invention. FIG. 2 is a longitudinal cross-sectional view of the vacuum heat insulating material 1 in the heat insulation tank of Embodiment 1 according to the present invention.

  As shown in FIGS. 1 and 2, the vacuum heat insulating material 1 includes a core material 10 made of, for example, a laminate of glass fiber sheets, and includes a layer having a gas barrier property and a layer having a heat fusion property. It is inserted into an outer bag 9 made of a laminate film and the inside is reduced in pressure and sealed, and its thermal conductivity is about 0.002 to 0.008 W / mK at 24 ° C. and has excellent heat insulation performance. is doing.

  As the core material 10 of the vacuum heat insulating material 1, for example, a dry silica powder, a carbon powder, a single product or a mixed product such as inorganic fiber, solidified or filled with a nonwoven fabric, a porous material, a foamed material, or the like can be used. However, both inorganic and organic substances can be used as long as they have heat resistance at the operating temperature, and are not particularly specified.

  Moreover, although it is also possible to provide the protective layer 11 on the surface of the outer bag 9 as needed, it is not particularly specified.

  The vacuum heat insulating material 1 is formed into a cylindrical shape by adding a curved surface or a corner to a flat plate shape, and is housed in the outer container 3 while surrounding the outer side of the inner container 2. A heating means 4 and a water supply path 5 are provided outside the bottom of the inner container 2, and a lid 7 is provided above the inner container 2.

  At this time, the shape of the inner container 2 is preferably a cylindrical shape from the viewpoints of easy care and space saving, but is not particularly limited.

  FIG. 3 is a perspective view of the vacuum heat insulating material 1 subjected to the cylinder processing in the heat insulating tank according to the first embodiment of the present invention.

  In FIG. 3, the vacuum heat insulating material 1 has a cylindrical shape by adding a curved surface or a corner to a flat plate shape, and is housed in the outer container 3 while surrounding the outer side of the inner container 2. Moreover, although the location which does not contain the core material 10 in the outer bag 9 of the vacuum heat insulating material 1 is called the fin 5, the fin 5 is bent to the cylinder outer side.

  FIG. 4 is a cross-sectional view of the laminate film of the outer bag 9 of the vacuum heat insulating material 1 in the heat insulation tank according to the first embodiment of the present invention.

  In FIG. 4, a protective layer 12 is provided on the uppermost layer of the laminate film constituting the outer bag 10 of the vacuum heat insulating material 1, and a gas barrier layer 12 is provided therebelow. Hereinafter, the heat welding layer 16 and these layers are bonded together. The adhesive 17 is made up of. The gas barrier layer 12 includes a base film 13, a vapor deposition layer 14, and a polyacrylic acid resin layer 15 in order from the outside.

  In the present embodiment, the protective layer 11 is a nylon film having a thickness of 25 μm as the outermost layer, and the gas barrier layer 12 therebelow is a polyethylene terephthalate film having a thickness of 12 μm, which is a base film 13 during vapor deposition, and a vapor deposition layer 14. It has an aluminum vapor-deposited layer 14 and a 1 μm polyacrylic acid-based resin layer 15, and further has a 50 μm low-density polyethylene film as a thermal fusion layer 16 as a lower layer, and a protective layer 11 and a gas barrier layer 12. And the heat sealing layer 16 were laminated with an adhesive 15.

  In addition, as the protective layer 7, for example, a nylon film, a polyethylene terephthalate film, a polyethylene naphthalate film, or the like can be applied, but other known materials can be used as long as they have a melting point higher than that of the heat sealing layer 16, Not specified.

  In the gas barrier layer 12, polyethylene terephthalate or polyethylene naphthalate can be applied to the base film 13, and aluminum, iron, copper, silver, alumina, silica, or the like can be applied to the material of the vapor deposition layer 14, but the gas barrier property and heat Other known materials can be used as long as they have a melting point higher than that of the fusion layer 16, and are not particularly specified.

  For example, low-density polyethylene, linear low-density polyethylene, high-density polyethylene, unstretched polypropylene, and the like can be applied to the heat-sealing layer 16, but other materials can be used as long as they have heat-fusibility and heat resistance in the operating temperature range. Known materials can be used and are not particularly specified.

  It should be noted that at least one side of the gas barrier layer 12 of the outer bag 9 may be a polyacrylic resin layer 15, a vapor deposition layer 14, and a base film 13, and the other side is a metal foil or polyacrylic resin layer 15. You may comprise from the vapor deposition layer 14 which does not have, and it does not specify especially about the material.

  Moreover, the bag shape of the outer bag 11 of the vacuum heat insulating material 1 may be a four-sided seal or a pillow shape as long as the internal vacuum degree can be maintained, and is not particularly specified. .

  In the electric water heater configured as described above, the operation and action will be described below. The liquid in the inner container 2 is heated and kept warm by the heating means 4, and during the heat keeping, the heat radiation from the inner container 2 is suppressed by the vacuum heat insulating material 1 covering the inner container side surface and part of the periphery of the lid 7. is doing.

  The vacuum heat insulating material 1 is made of a laminate film having a thickness of about 100 μm. A core material 10 in which an inorganic fiber sheet is laminated is inserted into an outer bag 9 sealed on three sides by heat fusion, and the inside is decompressed and heat fusion is performed. It is sealed by wearing. Since the vacuum heat insulating material 1 has a high gas phase ratio and a degree of vacuum, it has high heat insulating performance.

  In the present embodiment, since the vacuum heat insulating material 1 partially covers not only the periphery of the inner container 2 but also the periphery of the lid 7, heat leaked from the flange 6 that is the joint between the lid 7 and the inner container 2 is reduced. can do. At this time, not only the vacuum heat insulating material 1 itself has a very high heat insulating performance, but also because the heat conduction is reduced because the metal thickness is smaller than that of a conventional vacuum tube made of a metal double container, The heat leak through can be reduced. Therefore, the heat retaining property is improved, and the liquid can be kept warm for a long time with less energy. At this time, the vacuum heat insulating material 1 only needs to cover at least the periphery of the lid 7, but the higher the coverage, the better the heat insulation effect. Therefore, the coverage is preferably increased, but is not particularly specified.

  Further, the end of the heat-sealed outer bag 9 is kept at a low temperature by bending the fin 8 of the vacuum heat insulating material 1 toward the outside of the tube-shaped vacuum heat insulating material 1. Usually, since the oxygen permeability of the film increases in proportion to the increase in temperature, the amount of gas entering the vacuum heat insulating material 1 can be reduced by maintaining the heat-sealed portion 18 at a low temperature. Therefore, the increase in the internal pressure of the vacuum heat insulating material 1 can be prevented and the deterioration of the thermal conductivity with time can be prevented, so that the energy saving performance of the electric water heater can be maintained for a long time.

  The outer bag 9 of the vacuum heat insulating material 1 has a gas barrier layer 12 and a polyacrylic acid resin layer 15, and the polyacrylic acid resin layer 15 itself has a high gas barrier property. By providing this, since the polyacrylic acid molecule functions to compensate for defects between molecules in the vapor deposition layer, the gas barrier property is improved far more than when each is used as a single layer. Furthermore, since the polyacrylic acid resin layer 15 has a very excellent property of bending, no cracks are generated even when the vacuum heat insulating material is processed into a cylinder, and a gas barrier when cracks occur in the vapor deposition layer 14. The deterioration of the property can be reduced as compared with the conventional case. Further, since the polyacrylic resin layer 15 is very excellent in heat resistance, there is almost no deterioration during heat fusion.

  Further, since the polyacrylic acid resin layer 15 is configured to be inside the vapor deposition layer, the polyacrylic acid resin layer sandwiching the heat fusion layer 16 in the cross section of the heat fusion part 18 of the vacuum heat insulating material 1. Since the distance between 15 is reduced, intrusion of gas and moisture can be reduced.

  In addition, since the vapor deposition layer 14 and the polyacrylic acid resin layer 15 hinder the penetration of moisture contained in the base film 13 into the vacuum heat insulating material, in the case of using a highly hygroscopic resin for the base film 13 Also less susceptible to outgassing. Therefore, it is possible to prevent the deterioration of the initial performance of the vacuum heat insulating material 1 due to the improvement in reliability over time of the vacuum heat insulating material 1 and the moisture absorption of the film.

  Furthermore, by providing the polyacrylic acid resin layer 15 having a high gas barrier property on the vapor deposition layer 14, the polyacrylic acid molecules serve to compensate defects between the molecules of the vapor deposition layer 14, so that each of them is a single layer. The gas barrier property is improved far more than when it is used. Therefore, even when the vapor deposition layer 14 is a single layer, the reliability over time can be sufficiently maintained.

  Thereby, since the thickness of the vapor deposition layer 14 used for the laminated film of the outer bag 9 can be reduced as compared with the conventional case, the heat conduction of the outer bag 9 is reduced, and leakage through the outer bag surface is reduced. Electric water heaters can save energy and reduce costs.

  Various heat insulating materials were applied to the electric water heater, and the power consumption during heat retention was measured under a certain condition. The results are shown in (Table 1).

（実施例１）
実施例１における電気湯沸かし器について、保温時の消費電力を計測した。計測は２５℃室内にて行い、保温安定時の積算電力より、1時間あたりの電力量を求めた。真空断熱材１の外袋３は両面ともに、ポリエチレンテレフタレートの基材フィルム１３と、アルミ蒸着層１４一層と、その下に設置したポリアクリル酸系樹脂層１５とからなるガスバリア層１２を使用した。得られた保温時消費電力値を１とした。

(Example 1)
About the electric water heater in Example 1, the power consumption at the time of heat retention was measured. The measurement was performed indoors at 25 ° C., and the amount of power per hour was obtained from the integrated power when the temperature was stable. Both sides of the outer bag 3 of the vacuum heat insulating material 1 used a gas barrier layer 12 composed of a polyethylene terephthalate base film 13, an aluminum vapor deposition layer 14, and a polyacrylic acid resin layer 15 disposed thereunder. The obtained power consumption value during heat retention was set to 1.

(Example 2)
About the electric water heater in Example 2, the power consumption at the time of heat retention was measured. The measurement was performed in the same manner as in Example 1, and the outer bag 3 of the vacuum heat insulating material 1 was obtained by laminating two layers of a gas barrier layer 12 composed of an aluminum vapor deposition layer 14 and a polyethylene terephthalate base film 13 on both sides. As a result, the power consumption during heat retention was 1.1 times that in Example 1.

(Comparative Example 1)
The electric power consumption at the time of heat retention was measured for an electric water heater using a vacuum tube made of a metal double container as a heat insulating material and sealed with reduced pressure inside. Measurement was performed in the same manner as in Example 1. As a result, the power consumption during heat retention was 1.5 times that in Example 1.

  From the above, by changing from a vacuum tube made of a metal double container to a vacuum heat insulating material 1, heat conduction of the outer shell of the heat insulating material is greatly reduced, so that heat leakage through the outer shell of the heat insulating material can be prevented, It is thought that the effect of reducing power consumption was obtained. Furthermore, since the metal vapor deposition layer 14 of the vacuum heat insulating material 1 is made into one layer, the heat conduction of the outer bag 9 of the vacuum heat insulating material 1 is further reduced, so that the heat leakage through the outer bag 9 can be further reduced, and the power consumption is reduced. I think it was reduced.

  In this embodiment, the heat-insulating tank is an electric water heater, but is not particularly limited, and is not limited to rice cookers, heat-insulating cookers, water heaters, and devices for heat insulation such as hot water storage containers as well as electric and gas appliances. It can be applied if it is a kind, and it is possible to improve the long-term heat retention effect and reduce the amount of energy consumption.

(Embodiment 2)
FIG. 5 is a longitudinal sectional view of an electric water heater provided with a heat retaining tank according to the second embodiment of the present invention. In FIG. 5, the vacuum heat insulating material 1 covering the periphery of the inner container 2 is disposed longer than the inner container 2 in the vertical direction, and the heating means 4 installed at the bottom of the inner container 2 The surrounding area is covered.

  The heating means 4 warms the inner container 2 and transmits heat to the surrounding air, and the warmed air causes heat conduction by convection to the surroundings. Since the warmed air has the property of moving upward, it may leak between the vacuum heat insulating material 1 and the outer container 3, and as a result, the thermal efficiency of the heating means 4 deteriorates and the electric water heater is consumed. The amount of energy was increasing.

  In the present embodiment, the vacuum heat insulating material 1 is disposed longer than the inner container 2 in the vertical direction, and the heating means 4 is covered by covering the periphery of the heating means 4 installed at the bottom of the inner container 2. Therefore, the heat leaking in the direction of the outer container 3 can be cut off, and the heat retention of the electric water heater is improved. Moreover, since the heated air molecule convects in the upward direction, the heat blocked from leaking by the vacuum heat insulating material 1 is transferred to the inner container 2, so that the heating efficiency of the electric water heater is improved. Therefore, it is possible to reduce the energy consumption of the electric water heater.

  The vacuum heat insulating material 1 only needs to cover at least part of the lower direction than the inner container 2, but it is preferable to increase the coverage because the heat insulation effect is improved as the coverage is higher. Not what you want.

  As described above, the present invention improves heat retention and reduces energy consumption by effectively applying a vacuum heat insulating material. Therefore, it can utilize for energy saving measures, such as a device for the purpose of heat insulation, for example, a rice cooker, a water heater, a hot water tank, and a heat insulation cooker.

1 is a longitudinal sectional view of an electric water heater according to Embodiment 1 of the present invention. Sectional drawing of the vacuum heat insulating material in Embodiment 1 of this invention The perspective view of the vacuum heat insulating material when applied to the electric water heater in Embodiment 1 of this invention Sectional drawing of the laminated film of the outer bag of the vacuum heat insulating material in Embodiment 1 of this invention The longitudinal cross-sectional view of the electric water heater in Embodiment 2 of this invention Longitudinal sectional view of a conventional electric water heater Longitudinal sectional view of another conventional electric water heater

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material 2 Inner container 3 Outer container 7 Lid 9 Outer bag 10 Core material 14 Deposition layer 15 Polyacrylic acid-type resin layer

Claims (7)

  In the heat insulating tank having at least an outer container, a bottomed inner container housed inside the outer container, a lid covering the upper part of the outer container, and a vacuum heat insulating material surrounding the side surface of the inner container, the vacuum The heat insulating material is composed of at least a core material and an outer bag, and the inside is depressurized, and is disposed so as to cover at least a part of the side surface of the lid, and the outer bag is a heat insulating tank made of a film having a vapor deposition layer .   The heat insulating tank according to claim 1, wherein a lower end portion of the vacuum heat insulating material is disposed longer in the downward direction than the inner container.   The heat insulating tank according to claim 1 or 2, wherein at least a part of the outer bag at a location where no core material is present is bent toward the outer container.   The heat insulation tank according to any one of claims 1 to 3, wherein the outer bag of the vacuum heat insulating material has a laminated structure and has at least a polyacrylic acid resin layer adjacent to the vapor deposition layer.   The thermal insulation tank according to claim 4, wherein the polyacrylic acid resin layer is inside the vapor deposition layer.   The heat insulating tank according to claim 4 or 5, wherein the outer bag has a single vapor deposition layer.   The electric water heater provided with the heat retention tank as described in any one of Claim 1 to 6.

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