JPS6057865B2 - storage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a storage that is equipped with an oxygen absorption device and that can maintain the freshness of stored items, prevent spoilage, and prevent insects.

There are various types of storage such as refrigerators used to cool and preserve various foods and drinks, heat storages used to keep food warm, and clean boxes used in hospitals to keep tweezers, syringes, etc. clean. Widely used.

Among these, especially in the heat storage, the temperature should be 40 to 80℃.
Because it is kept in
It has the disadvantage of easily causing food discoloration, taste change, or spoilage.

Furthermore, since the internal temperature of refrigerators is usually maintained at a relatively low temperature of around 5° C., food spoilage is relatively unlikely to occur. Some bacteria have a relatively large reproductive capacity even at low temperatures.
Furthermore, especially in the summer, it may be difficult to maintain the internal temperature at around 5° C. by opening and closing the door, and there is a risk that food will spoil even in the refrigerator. In addition, various considerations have been made in cleaning boxes used in the medical field, such as using germicidal lamps to suppress the growth of bacteria, but there are some areas where the germicidal light is not irradiated in a straight line.
Not enough.

In such storages, combustion gas such as propane gas or carbon dioxide gas is pumped into the storage to prevent the growth of bacteria and insects, or to keep vegetables, fish, fruits, etc. fresh. It has been implemented to reduce the concentration of oxygen gas within. Alternatively, oxygen can be absorbed and removed using various chemicals. This method is said to be highly effective, but the combination of chemicals and oxygen (
compound), then this chemical must be replaced with a new one. Because air contains a relatively large amount of oxygen gas (approximately 21%), and chemicals such as pyrogallol have a low oxygen absorption capacity, they must be replaced in a short period of time. The present invention continuously absorbs oxygen gas in the refrigerator using a simple method.
It relates to means for removing.

A method has already been proposed in which oxygen gas is absorbed by a metal electrode using an alkaline electrolyte. Examples of metal electrodes include cadmium electrodes, zinc electrodes, and iron electrodes, which reversibly repeat the cycle of oxygen gas absorption and electrolytic reduction. This method has the disadvantage that carbon dioxide gas in the air is absorbed into the alkaline electrolyte, resulting in alkali consumption and pollution. The present invention uses a gel-like solid electrolyte containing sulfuric acid, which is an acidic electrolyte, and a lead electrode that absorbs oxygen gas and can regenerate the generated lead oxide into lead through an electrochemical reduction reaction. The present invention eliminates the disadvantages of the prior art and provides a storage device with a continuously operating electrochemical oxygen absorption element.

According to the present invention, by selectively releasing oxygen gas inside the storage to the outside, the oxygen inside the storage is reduced, and spoilage of food and breeding and invasion of bacteria and insects are significantly suppressed. I can do it.

Bacteria are broadly classified into aerobic and anaerobic; the former are bacteria that require the presence of molecular oxygen for growth, and the latter are bacteria that dislike the presence of oxygen. However, the bacteria that actually cause discoloration, taste, and spoilage of food are the former.
Typical examples include vinegar, acid bacteria, gluconic acid bacteria, Mycobacterium tuberculosis, Mycobacterium diphtheriae, and other molds. It is natural that insects dislike places with little oxygen.
It also helps preserve the freshness of vegetables, fruits, fresh flowers, etc. This is thought to be based on reducing or stopping the respiratory activity of these plants by making the atmosphere hypoxic. In the present invention, a lead electrode is combined with an acidic electrolyte, and the electrolyte is solidified instead of a flowing liquid electrolyte. This eliminates electrolyte leakage and outflow, and increases the absorption rate of oxygen gas. The reason for this is thought to be as follows. In other words, by making this gel electrolyte into a gel-like state with low water content, as is generally used in sealed lead batteries,
Gas can flow freely through this. If this is used, oxygen gas can be absorbed by the entire electrode. On the other hand, the field of fluid electrolyte! In this case, the lower part of the electrode is submerged in liquid, or even if it is an impregnated type, it contains a lot of liquid, so it is difficult for the electrode surface to come into direct contact with oxygen gas, so the absorption rate of oxygen gas is slow; Since there is little moisture in the electrode, the absorption rate is slow, and during regeneration, the ionic conductivity (degree) is small in this part, so it is difficult for the regeneration current to flow in this part, and therefore regeneration is difficult. Only the moist part, for example the central part, can participate in gas absorption, whereas with a solid electrolyte the entire electrode operates uniformly, resulting in a high oxygen absorption rate.
Further, since concentrated sulfuric acid is hygroscopic, when water evaporates to a certain extent, the sulfuric acid concentration inevitably increases, and therefore exhibits hygroscopicity and replenishes water from the atmosphere.

Therefore, the moisture contained in the gel electrolyte remains within a certain range, and there is an advantage that maintenance such as water replenishment or drying is not required. The present invention will be explained below with reference to Examples.

FIG. 1 shows a storage 2 in which an electrochemical element 1 is provided on the storage wall, and 3 and 4 are doors.

FIG. 2 shows the structure of the element 1, with reference numeral 5 indicating the refrigerator wall to which the element 1 is attached, reference numeral 6 indicating the inside of the refrigerator, and reference numeral 7 indicating the outside of the refrigerator. Reference numeral 8 denotes a polyvinyl chloride battery case of the element 1, which has a window 9 on the part facing the inside of the refrigerator and a gas discharge port 10 on the outside of the refrigerator.

Reference numeral 11 is a porous lead electrode, and the electrode is inserted so as to close the window 9.
It is attached to tank 8.

12 is a counter electrode serving as a gas generating electrode, and is made of a graphite plate.

These electrodes 11 and 12 have a size of 10×125 and a thickness of about 2 m. 13 is a gel-like solid electrolyte containing sulfuric acid, which is made of water glass containing 55% by weight of Na2SiO3 and concentrated sulfuric acid in a volume ratio of 1:1.

Reference numeral 14 designates a diaphragm that blocks the flow of gas between the two electrodes but has ionic conductivity, such as a 0.2-thick cation exchange membrane having a sulfone group.

This diaphragm has the role of preventing oxygen gas generated from the counter electrode 12 from migrating to the inside of the refrigerator. Reference numeral 15 denotes a constant voltage power supply that rectifies alternating current into a direct current voltage of approximately 1V.

Note that silicate gel/starch, gelatin, agar, polyvinyl alcohol, saponin, konjac, pectin, etc. can also be used instead of water glass constituting the gel-like solid electrolyte.

Gas-impermeable and ion-permeable diaphragms include various ion exchange membranes, hydrophilically treated microporous polypropylene and polyethylene membranes, woven fabrics of these resin fibers,
A nonwoven fabric impregnated with an electrolyte can be used. Next, the principle of operation of this element will be explained.

If there is oxygen gas in the refrigerator, the lead electrode 11 will react (
Absorb oxygen gas as shown in equation 1) or equation (2). Then, when a voltage is applied to both electrodes with the lead electrode being negative and the counter electrode being positive, the lead electrode is regenerated according to the following equation in the case of equation (1), for example. On the other hand, at the counter electrode, the same amount of oxygen as in equation (1) is generated according to equation (4).

The same applies to Yang He, who considered the gas absorption reaction of the lead electrode to be expressed by equation (2).

Eventually, the oxygen gas inside the refrigerator will be absorbed by the element 1 and released outside the refrigerator.

The regeneration current value decreases as the oxygen concentration in the refrigerator decreases, and the current becomes zero when oxygen is exhausted. Therefore, each time the storage door is opened or closed to replace some of the air, this device automatically operates to keep the oxygen gas inside the storage at a low concentration at all times. FIG. 3 shows the results when this device is applied to a storage with an internal volume of 100e. In the figure, curve A is the result when using the gel-like solid electrolyte according to the present invention. For comparison, curve B shows the results when a normal aqueous sulfuric acid solution was used instead of the gel electrolyte. In this case, the best liquid volume is when the lower part of the electrode (approximately 115 mm) is immersed, so the results in this case are shown. As described above, when using this device, the amount decreased to 9% in about 3 minutes after the door was closed, and to about 3% in 1 hour, which is about three times faster than when using a liquid electrolyte. The reason for this is thought to be that the entire lead electrode operates as described above. It is clear that the invention is equally applicable to other storage areas such as refrigerators, thermal storage cabinets, kitchen sinks, and clean boxes.

Note that the oxygen removal device according to the present invention does not necessarily have to be installed on the refrigerator wall, but may be installed inside or outside the refrigerator and connected by a vibrator to circulate the air.

As described above, according to the present invention, oxygen in the refrigerator can be absorbed continuously and economically, so that it is effective for maintaining the freshness of stored items, preventing spoilage, and preventing insects.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a storage in an embodiment of the present invention;
FIG. 2 is a longitudinal sectional view of the electrochemical element, and FIG. 3 is a diagram comparing changes in oxygen concentration inside the refrigerator. 1... Electrochemical element, 2... Storage, 11...
Lead electrode, 12... counter electrode, 13... electrolyte, 14...
・Diaphragm, 15...Power supply.

Claims (1)

[Claims] 1. A lead electrode that can absorb oxygen gas and regenerate the generated lead oxide through an electrochemical reduction reaction, a counter electrode, a gel-like solid electrolyte containing sulfuric acid in contact with both electrodes, and a gas-impermeable material interposed between both electrodes. It is equipped with an electrochemical element consisting of an ion-permeable diaphragm and a power source that applies a DC voltage to both electrodes with the lead electrode side negative, and the lead electrode is brought into contact with the gas phase in the refrigerator, and the opposite electrode side is A storage chamber configured to communicate with outside air.