JPH0129599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat storage device that suppresses temperature drop using a heat storage material.

Conventional Technology In recent years, there has been a desire to develop heat storage devices that can be applied to various home appliances such as irons and warming trays that can be disconnected from the power source during use to improve operability.

Home appliances such as irons and heating trays usually cost 200 yen.
Pentaerythritol is used as a heat storage material for these home appliances because it is used at temperatures below ℃ and uses a large amount of heat.
is the most suitable. This is because pentaerythritol undergoes a crystal transition at 188°C, and the latent heat of transition at this time is extremely large, approximately 300 J/g, making it possible to secure sufficient heat storage capacity for small heat storage devices, such as home appliances such as those mentioned above. This is because it can be done.

Problems to be solved by the invention Pentaerythritol is one of the organic substances that is relatively stable against heat, but when exposed to high temperatures in the air for a long time, it deteriorates due to oxidation and the amount of heat stored gradually decreases. It is known that it will decrease. especially
It has become clear that even in a closed system where outside air is cut off at high temperatures exceeding 200°C, the presence of a substance that does not coexist with pentaerythritol in the system causes a similar reduction in heat storage.

As an example of this, FIG. 7 shows experimental results showing the coexistence of pentaerythritol, which is the main material of the heat storage material, with three types of metals: brass, aluminum alloy, and iron.
The experiment was conducted in the following manner. That is, pentaerythritol and test pieces of each metal were mixed in a glass tube, sealed, and continuously heated in an atmosphere of 220°C.
The amount of heat stored per unit weight of each sample was measured at each elapsed time. Figure 7 shows a sample containing only pentaerythritol, a sample containing pentaerythritol mixed with a brass test piece, a sample containing an aluminum alloy test piece, and a sample containing an iron test piece. The results of the durability test are shown. From this result, it can be seen that when pentaerythritol and metal are heated for a long time in a state in which they are in contact with each other, the heat storage performance of pentaerythritol is significantly reduced.

In general, storage chambers for storing heat storage materials are usually constructed of metal for reasons such as heat resistance, thermal conductivity, and mass productivity. This indicates that metals are unsuitable, and has been a problem in putting pentaerythritol into practical use as a heat storage material.

Another problem is that if pentaerythritol is completely sealed in the storage chamber to prevent pentaerythritol from deteriorating due to oxygen as mentioned above, even if the storage chamber is made of materials other than metals that are compatible with each other, it will not be possible to use the pentaerythritol for a long time. After that, pentaerythritol deteriorated, and the decomposition gas generated gradually accumulated in the storage chamber, posing a risk that the internal pressure in the storage chamber would continue to rise.

The present invention solves these problems,
To realize a highly safe heat storage device that maintains durability without accelerating deterioration even when pentaerythritol is stored in a storage chamber made of metal, and that does not have to worry about internal pressure increasing in the storage chamber even during long-term use. The purpose is to

Means for Solving the Problem In order to solve this problem, the heat storage device of the present invention includes a heat storage container that encloses pentaerythritol made of fluororesin, and this heat storage container is fixed to a metal storage chamber. It is accommodated.

Effect With this configuration, the fluororesin, which is inert to pentaerythritol, prevents the pentaerythritol from coming into contact with the metal surface of the storage chamber, preventing a decrease in the amount of heat stored in the pentaerythritol, and even after long-term use, the fluororesin Due to the appropriate air permeability of the heat storage container, the decomposition gas inside the heat storage container containing pentaerythritol is gradually discharged, and there is no fear that the internal pressure will rise abnormally.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

FIG. 1 shows a heat storage device in one embodiment of the present invention. In the figure, 1 is a heat storage container molded with pentaerythritol, 2 is a heat storage container molded with fluororesin,
Pentaerythritol 1 is enclosed and sealed.
3 is a metal storage chamber for accommodating the heat storage container 2. 4 is a silicone rubber for fixing the heat storage container 2 housed in the storage chamber 3, which is made by hardening liquid silicone rubber applied so as to cover the opening of the storage chamber 3. Reference numeral 5 denotes a heating element for heating the pentaerythritol 1, which is attached to the bottom of the storage chamber 3. By sealing the pentaerythritol 1 in the heat storage container 2, the pentaerythritol 1 is not exposed to the air, and the heat storage container 2, which is made of a fluororesin that is inert to the pentaerythritol 1, is in a storage room with the pentaerythritol 1. Since the pentaerythritol 1 is isolated and not in direct contact with the metal, even if the heating element 5 continues to heat the pentaerythritol 1 above the heat storage temperature for a long period of time, the amount of heat stored in the pentaerythritol 1 will not decrease due to the metal.

FIG. 2 shows an example of experimental results showing that among various heat-resistant resins, fluororesin is inactive against pentaerythritol. The experimental method was the same as that shown in Figure 7. Pentaerythritol and test pieces of each heat-resistant resin were mixed in a glass tube, sealed, and a continuous heating test was performed in an atmosphere of 220°C. We are measuring changes in the amount of heat storage. In the figure, A is pentaerythritol only, B
is a mixture of pentaerythritol and fluororesin (PTFE), C is a mixture of epoxy resin, D is a mixture of polyimide resin,
Similarly, E shows a product to which polyimide resin (66-nylon) is added, but all other materials other than fluororesin have poor coexistence with pentaerythritol, causing a decrease in the heat storage amount of pentaerythritol. In particular, it has the highest heat resistance among fluororesins.
Three types of materials are used for the heat storage container 2: PTFE (tetrafluoroethylene resin), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin), and FEP (tetrafluoroethylene-hexafluoropropylene copolymer resin). I found it suitable.

Furthermore, fluororesin has higher gas permeability than other resins, and even if the heat storage container 2 is completely sealed by welding etc., the gas generated inside the heat storage container 2 will be gradually exhausted, so it will not be suitable for long-term use. Therefore, even if the deterioration of pentaerythritol 1 progresses, the internal pressure of the heat storage container 2 will not rise abnormally.

FIG. 3 shows the gas permeability of resins, and it can be seen that fluororesin has a large gas permeability coefficient and high gas permeability. Furthermore, silicone rubber, which generally has a high gas permeability, has a very good gas permeability.

Therefore, even if the entire heat storage container 2 is covered with silicone rubber 4 and fixed to the storage chamber 3 as in this embodiment, the ventilation between the inside of the heat storage container 2 and the outside air is maintained, and at the same time,
By changing the thickness of the silicone rubber 4 depending on the size of the opening of the storage chamber 3, the degree of air permeability can be controlled.

FIG. 4 shows a second embodiment of the invention. In the figure, 2' is a heat storage container formed by thermally welding a fluororesin film into a bag shape, in which pentaerythritol 1 is enclosed and hermetically sealed. 3 is a storage room, 5
is a heating element, which is the same as in Fig. 1. 6 is silicone oil interposed between the heat storage container 2' and the storage chamber 3;
Silicone such as silicone grease or silicone rubber fixes the heat storage container 2' in the storage chamber 3 and improves heat conduction between the heat storage container 2' and the storage chamber 3. Reference numeral 7 denotes a metal lid member attached to the opening of the storage chamber 3, which presses and fixes the heat storage container 2' from above with silicone 6 interposed therebetween.

By enclosing pentaerythritol 1 in the bag-like heat storage container 2' in which a fluororesin film is thermally welded, pentaerythritol 1 does not come into direct contact with the outside air or the metal in the storage chamber 3, so it does not deteriorate due to the effects of these. Therefore, even if the pentaerythritol 1 deteriorates after long-term use, the gas permeated by the gas permeability of the fluororesin will not occur between the metal lid 7 and the storage chamber 3. Since the heat is gradually discharged to the outside through the silicone 6, the internal pressure of the heat storage container 2' does not continue to rise. Moreover, by constructing the heat storage container 2' with a fluororesin film in this manner, productivity is improved, and PTFE, which is inexpensive among fluororesins but has poor moldability, can also be used, which is advantageous in terms of cost. Further, by interposing the silicone 6 between the heat storage container 2' and the storage chamber 3, heat conduction between the two is improved, the heating characteristics of the pentaerythritol 1 by the heating body 5 are improved, and the heat storage time can be shortened.
Note that if a curable liquid silicone rubber is used as the silicone 6, the heat storage container 2' can be completely fixed, so the lid member 7 can be a very simple one.

FIGS. 5 and 6 show an embodiment in which the heat storage device of the present invention is applied to an iron. In the figure, 11 is a heat storage material made by compression molding pentaerythritol, and 12 is a heat storage container made of fluororesin.The inside is filled with the heat storage material 11 and the surrounding area is sealed by heat welding to form an airtight container. . 13 is a base made of aluminum alloy, and a heat storage container 12 is placed on the top surface.
A storage chamber 14 for storing the items is integrally molded. 15
16 is a curable liquid silicone rubber interposed between the heat storage container 12 and the storage chamber 14, and 16 is the storage chamber 14.
An aluminum lid member screwed into the opening of the
The heat storage container 12 is pressed and fixed with liquid silicone rubber 15 interposed around the periphery. 17 is a heater for heating the base 13 and the heat storage material 11;
It is buried in the base 13.

With the above configuration, if power is connected to the heater 17 in advance to heat and store heat in the heat storage material 11, even if the power is disconnected from the heater 17, the heat storage material 1
1 suppresses the temperature drop of the base 13. Therefore, ironing can be done without a power source and without having to worry about power cords. In addition, by sealing the heat storage material 11 containing pentaerythritol as a heat storage material in the heat storage container 12 molded with fluororesin, the heat storage material 11 is not directly exposed to the outside air or comes into contact with the aluminum alloy of the base 13, thereby storing heat. The durability of the material 11 is greatly improved, and the gas permeability of the fluororesin prevents the internal pressure of the heat storage container 12 from increasing abnormally even during long-term use. Furthermore, a heat storage container 12 and a storage chamber 13
By interposing liquid silicone rubber 15 between
can dissipate heat efficiently.

As described above, by applying the heat storage device of the present invention to an iron, an iron with excellent operability, durability, and safety can be realized.

Effects of the Invention As described above, the present invention prevents a decrease in the amount of stored heat of pentaerythritol by forming a heat storage container that encloses pentaerythritol from a fluororesin and fixing the heat storage container in a metal storage chamber. Therefore, it is possible to provide a heat storage device that is excellent in both durability and safety, and the internal pressure of the heat storage container does not abnormally increase even during long-term use.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a heat storage device according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing the coexistence of various heat-resistant resins and pentaerythritol, and FIG. 3 is a characteristic diagram showing the gas permeability of the resin. Figure 4 shows the second embodiment of the present invention.
5 is a cross-sectional view of a main part of an embodiment in which the heat storage device of the present invention is applied to an iron, FIG. 6 is a perspective view of the same, and FIG. 7 is a cross-sectional view of various metals and pentaerythritol. It is a characteristic diagram showing the coexistence of. 1...Pentaerythritol, 2,2',12
... Heat storage container, 3, 14 ... Storage chamber, 4 ... Silicone rubber, 6 ... Silicone, 7, 16 ... Lid member.

Claims (1)

[Scope of Claims] 1. A heat storage device in which a heat storage container that encloses pentaerythritol as a heat storage substance is made of fluororesin, and this heat storage container is housed in a storage chamber made of metal. 2. The heat storage device according to claim 1, wherein the opening of the storage chamber is covered with silicone rubber to secure the heat storage container. 3. The heat storage device according to claim 1 or 2, wherein the heat storage container is pressed into the storage chamber by a lid member attached to the opening of the storage chamber. 4. The heat storage device according to claim 1, 2, or 3, wherein the heat storage container is fixed to the storage chamber by interposing silicone between the heat storage container and the storage chamber.