JP6744845B2 - Freshness preservation device for fresh agricultural products - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention uses OH radicals generated by irradiation of ultraviolet rays to convert harmful ethylene contained in the air in the chamber into harmless ethane and water, thereby maintaining the freshness of fresh agricultural products for a long period of time. Regarding the device.

It is possible to remove ethylene from the fresh produce of vegetables and fruits such as apples and bananas, because ethylene is generated by itself to reduce the freshness of the fresh produce in the refrigerator and to promote spoilage. Has been done.

In order to remove ethylene from the inside of the chamber, there are a method of putting a gas adsorbent such as activated carbon into the chamber to adsorb and remove ethylene, and a method of decomposing and removing ethylene by plasma discharge.
However, in the method using the gas adsorbent, the adsorption performance deteriorates when it is continuously used, and it is necessary to replace it with a new one as appropriate, which is very troublesome to manage.
Further, in the method of decomposing ethylene by the plasma discharge, a high voltage is used, so that a large-scale device and a large amount of power consumption are required, and the temperature in the cool box to be cooled by the heat generation of the plasma due to the application of the high voltage current. On the contrary, there is a problem that the harmful ozone is generated by the plasma.

Under such circumstances, the present inventor has previously proposed the ultraviolet ray freshness preserving device disclosed in Patent Document 1 below.
In this proposal, OH radicals are generated in the water droplets by irradiating the water droplets attached to the water retaining body with ultraviolet rays, and the harmful OH radicals are contacted with harmful ethylene in the air to produce ethane and water that are harmless for keeping freshness. It has become possible to improve the freshness of the fresh produce in the warehouse by modifying it.

Japanese Patent No. 4332107

However, in carrying out the apparatus of Patent Document 1, although ethylene can be reformed, the problem that the water retaining body and the plastic parts in the apparatus are deteriorated due to the irradiation of ultraviolet rays to shorten the life of the product and the generation of OH radicals. There was a problem that the water required for the water must be forcibly supplied with a sprayer or the like.
Therefore, the present invention maintains the freshness of the fresh agricultural products in the refrigerator by generating OH radicals using ultraviolet rays and titanium dioxide and modifying the harmful ethylene in the air in the refrigerator to make them harmless. Although it is possible, water can be obtained from moisture in the air without using a water supply device such as a sprayer, and the ultraviolet rays that irradiate it can be used for a long time without deterioration or damage to the parts inside the device A device is provided.

In order to solve the above problems, the freshness-retaining device for fresh produce of the present invention is designed to bring harmful ethylene generated from fresh produce into harmless ethane and water by bringing it into contact with OH radicals generated on the surface of titanium dioxide by ultraviolet irradiation. This is a freshness-maintaining device installed in the cold storage that reforms and keeps the freshness of the fresh produce in the cold storage for a long period of time.One intake port that sucks in air by the operation of the blower fan and the other exhaust gas that exhausts air. A ventilated flat plate-like filter in which titanium dioxide is exposed so as to come into contact with air is disposed in a housing having a mouth so as to block a ventilation path that passes from the intake opening to the exhaust opening in the housing. Then, an ultraviolet ray emitting tube capable of irradiating ultraviolet rays having a wavelength of 254 nm is arranged at a distance of 20 mm to 30 mm along the surface of the filter on the air intake side, and the filter is provided at a distance of 15 mm to 35 mm from the ultraviolet ray emitting tube. An ultraviolet arc tube capable of irradiating ultraviolet rays having a wavelength of 300 nm to 400 nm in parallel at a distance of 20 mm to 30 mm from the surface of the air suction side of the ultraviolet arc tube capable of irradiating ultraviolet rays having a wavelength of 254 nm. It is characterized in that the main arrangement is made.

According to a second aspect of the present invention, in the above invention, the central ultraviolet ray emitting tube capable of irradiating the ultraviolet ray having a wavelength of 254 nm and the ultraviolet ray emitting tubes capable of emitting the ultraviolet ray having a wavelength of 300 nm to 400 nm on both sides thereof are provided. It is characterized in that the unit is an ultraviolet light emitting tube unit, and a plurality of the ultraviolet light emitting tube units are installed in one housing.

According to a third aspect of the present invention, in the above invention, a reflection plate is provided near the air suction side of each of the ultraviolet light emission tubes to cover an outer peripheral surface of each of the ultraviolet light emission tubes on the air suction side.

According to a third aspect of the present invention, in the above invention, a protective filter is provided at the exhaust port and the intake port of the housing to block the opening so that the opening can be ventilated.

The present invention, in the housing, the moisture in the air blown by a blower fan on the surface of titanium dioxide of a flat plate-shaped filter exposed so as to be able to come into contact with air is supplemented and adhered to the surface of the filter. An ultraviolet light emitting tube capable of irradiating ultraviolet rays having a wavelength of 254 nm arranged at a distance of 20 mm to 30 mm, and a distance of 20 mm to 30 mm from the suction side surface of the filter on both sides with an interval of 15 mm to 35 mm from the ultraviolet light emitting tube. The UV arc tube capable of irradiating ultraviolet rays having a wavelength of 300 nm to 400 nm is disposed at the same time, and ultraviolet rays having a wavelength of 254 nm and ultraviolet rays having a wavelength of 300 nm to 400 nm are simultaneously applied to the water adhering to the surface of titanium dioxide of the filter from three directions. By irradiation, the chemical action of the ultraviolet rays and the photocatalytic action of titanium dioxide make it possible to reliably generate OH radicals on the surface of titanium dioxide.
Then, regarding the supply of water to the surface of the filter during operation of the blower fan, a filter in the form of a flat plate with a large air contact area that allows ventilation and a combination of titanium dioxide having superhydrophilicity exposed in the air To increase the contact area of the air containing moisture and to wet the titanium dioxide 4 with the moisture, and to supply the moisture without using a water supply device such as a sprayer which causes the complication and failure of the device. It becomes possible to obtain the water necessary for the generation of OH radicals on the surface of the titanium dioxide 4 without consuming electric power for the above.

Then, in the process in which the air containing ethylene sent by the blower fan passes through the surface of the filter and the surface of titanium dioxide exposed in the ventilation passage so as to rub, the OH in the water on which the surface of titanium dioxide is adhered. Ethylene comes into contact with radicals, and harmful ethylene is reformed into harmless ethane and water by the action of OH radicals.
As a result, the air containing ethylene sucked from the suction port of the housing becomes the air depleted of ethylene and is continuously discharged from the discharge port, and the air circulation in the storage is repeated and stored in the storage. The increase in the concentration of ethylene in the air, which is constantly generated from fresh agricultural products, is suppressed, and the freshness of fresh agricultural products is maintained for a long period of time.

At that time, the ultraviolet rays emitted from the ultraviolet ray emitting tube having a wavelength of 254 nm have a strong chemical action and may deteriorate the filters and various parts made of plastic in a short distance, but in the present invention, the ultraviolet ray emitting tube having a wavelength of 254 nm is used. The distance to the various parts in the housing is one by one, and the ultraviolet light emitting tube with a wavelength of 254 nm has a distance to the filter of 20 mm or more to suppress deterioration of the filter and is arranged in the center of the housing. It is possible to greatly separate them and suppress the deterioration of the components in the housing.
At the same time, it is possible to irradiate ultraviolet rays having a wavelength of 254 nm having a short wavelength arranged in the center and having a large chemical action. It is possible to radiate ultraviolet rays having a wavelength of 300 nm to 400 nm having a longer wavelength and having a smaller chemical action to both sides of the ultraviolet ray emitting tube. Even in the ultraviolet arc tube, the deterioration of the filter can be suppressed by keeping the distance to the filter to 20 mm or more.
On the other hand, the UV emission tube of wavelength 300 nm to 400 nm is placed at a distance of 15 mm to 35 mm from the UV emission tube of wavelength 254 nm in the center, so that it is possible to ensure that the UV emission tube in the surface of titanium dioxide is contained in the water by three UV emission tubes in total. It is possible to generate OH radicals.
That is, it becomes possible to significantly improve the useful life of the freshness preservation device by suppressing the deterioration of the filter and various parts in the housing due to ultraviolet rays while efficiently and reliably reforming ethylene.

Further, at that time, the number of 2 to 1 ultraviolet ray emitting tubes having a wavelength of 254 nm, which may generate ozone, is smaller than that of the ultraviolet ray emitting tubes capable of emitting ultraviolet rays having a wavelength of 300 nm to 400 nm where ozone is hardly generated. By combining them, the generation of harmful ozone can be suppressed.

The invention according to claim 2 is one in which the three ultraviolet arc tubes are one ultraviolet arc tube unit, and a plurality of the ultraviolet arc tube units can be installed in one housing. It is possible to increase or decrease the number of ultraviolet arc tube units according to the scale, and it is possible to provide an apparatus suitable for the scale of the interior space.

According to a third aspect of the present invention, a reflection plate that covers the outer peripheral surface is provided in the vicinity of the air intake side of each of the ultraviolet ray emitting tubes for each of the ultraviolet ray emitting tubes. It is possible to reflect a larger amount of ultraviolet rays to the filter by reflecting the ultraviolet rays emitted to the air suction side of each ultraviolet ray emitting tube toward the filter side while holding the above.
As a result, it becomes possible to generate more OH radicals in the ventilation filter and more efficiently reform harmful ethylene by the action of the OH radicals.

The invention according to claim 3 prevents a foreign matter such as dust, dust, and insects from entering the casing 1 by providing a protective filter that blocks the exhaust port and the intake port of the casing so as to allow ventilation. Therefore, it becomes possible to prevent the dead bodies of insects due to dust or ultraviolet rays from accumulating on the bottom of the housing 1.
Further, on the side of the exhaust port 1b, it is possible to prevent damage to the filter 3 containing the titanium dioxide 4 which is brittle and easily broken due to external contact or impact, which facilitates maintenance such as cleaning and repair for long use.

FIG. 1 is a vertical side view of the present invention. FIG. 2 is a horizontal sectional view of the present invention. FIG. 3 is a front view showing the filter and the ultraviolet light emitting tube excluding the housing. FIG. 4 is a schematic diagram showing a state in which the present invention is installed in a refrigerator. FIG. 5 is a schematic diagram showing that ethylene is reformed by an ultraviolet light emitting tube and a filter. FIG. 6 is a horizontal sectional view showing a mode in which a reflector is provided. FIG. 7 is a graph showing the relationship between the irradiation distance of the ultraviolet arc tube and the ultraviolet irradiation degree. FIG. 8 is a graph showing the time-dependent decay state of ethylene with and without the apparatus of the example.

The freshness-retaining device for fresh agricultural products of the present invention will be described below with reference to the drawings.
Since the present invention removes harmful ethylene generated from fresh agricultural products such as vegetables and fruits from the air in the storage, as shown in FIG. 4, the freshness to be installed in the storage 14 such as a cold storage for storing the fresh agricultural products 15 It is a holding device.
In FIG. 4, harmful ethylene E (indicated by a black arrow) is generated from the fresh agricultural product 15 of the present invention and is released into the air in the space S in the refrigerator, and the ethylene E circulates in the refrigerator 14. It is carried by the airflow K (indicated by the line arrow) and passes through the inside of the freshness preservation device under the ceiling through which the circulating airflow K passes, at which time ethylene E (indicated by the black arrow) is ethane e (white arrow). (Shown in FIG. 4) and is discharged into the container 14.
Although FIG. 4 shows a mode in which the freshness preservation device of the present invention is installed on the ceiling that does not interfere with the storage of the fresh agricultural products 15 in the refrigerator 14, the freshness preservation device has a circulating air flow K in the interior space S. It is preferable to install it in a place suitable for generating, and it can be installed in any place that does not interfere with the storage of the fresh agricultural products 15 such as the upper part of the wall surface.

The freshness preservation device of the present invention, as shown in FIGS. 1 and 2, has a housing 1 provided with one intake port 1a for sucking in air and the other exhaust port 1b for discharging the sucked air. The ventilation fan 2 mounted on the intake port 1a of the housing 1 and the ventilation port installed on the exhaust port 1b side so as to block the ventilation path passing from the intake port 1a in the housing 1 to the exhaust port 1b are ventilated. A flat plate-shaped filter 3, an ultraviolet arc tube 5 capable of irradiating ultraviolet rays having a wavelength of 254 nm along a surface 3a of the filter 3 at the center of the housing 1 on the air intake side, and 300 nm on both sides of the ultraviolet arc tube 5 And an ultraviolet arc tube 6 capable of irradiating ultraviolet rays having a wavelength of 400 nm.
Then, in order to fix the freshness preservation device of the present invention to the ceiling or the like in the refrigerator 14, the housing 1 is provided with a mounting portion (not shown) to the ceiling with bolts, nuts or the like.

The blower fan 2 may be of a type in which a propeller is rotated by a motor 7 to blow air. As shown in FIGS. 1 and 2, one or a plurality of blower fans 2 may be installed in the housing 1. It is provided so as to partition the intake port 1a.
A motor 7 for operating the blower fan 2 is connected to a power supply line 10 via a motor wiring 8.
When the blower fan 2 is operated, the air in the cabinet 14 is sucked into the housing 1 from the intake port 1a, and the air blown to the filter 3 passes through the filter 3 and the exhaust port 1b. Will be discharged to the outside of the refrigerator 14.

As shown in FIGS. 1 and 2, the filter 3 has a rectangular flat plate shape, and as shown in FIG. 5, air passes from the front side to the back side through the gaps between the particles of titanium dioxide 4. A possible ventilation path F is formed, and the surface and the ventilation path F are exposed so that the titanium dioxide 4 is exposed so as to be in contact with the air. As shown in FIGS. It is arranged in the housing 1 so as to partition the exhaust port 1b.
In the filter 3, the air blown from the intake port 1a into the housing 1 by the blower fan 2 passes through the air passage F of the filter 3, and ethylene E in the air is captured by the filter 3 during the passage. It will be.

It should be noted that, as shown in FIG. 1, the exhaust port 1b and the intake port 1a of the housing 1 are provided with cloth-made protective filters 16 and 17 having excellent ventilation and a metal net so that the openings can be ventilated. By blocking, it becomes possible to prevent dust, dirt, and insects from entering the housing 1, and to prevent dead bodies of insects and the like due to dirt and ultraviolet rays from accumulating on the bottom of the housing 1.
Further, on the side of the exhaust port 1b, it is possible to prevent the filter 3 including the titanium dioxide 4 from being damaged by external contact or impact.

The particles of titanium dioxide 4 in the filter 3 have superhydrophilicity and have a function as a photocatalyst that performs a chemical action. It hits and gets wet.
Then, as shown in FIG. 5, when the water w that wets the surface of the particles of titanium dioxide 4 is irradiated with ultraviolet rays A from the ultraviolet ray emitting tubes 5 and 6, electrons are excited and water molecules become oxygen and hydrogen ions. Is decomposed into OH radicals.
Then, when ethylene E in the air comes into contact with the OH radicals generated in the water on the surface of the titanium dioxide 4, it is reformed into harmless ethane e and water w.
Although OH radicals for modifying ethylene E are generated in water, the water w generated when modifying ethylene E also adheres to the surface of the particles of titanium dioxide 4 and is added to this water w. OH radicals are also generated.
Further, since the filter 3 has a flat plate shape, it is necessary without using a water supply device such as a sprayer, which increases the contact area of air containing moisture and causes power consumption and device complexity and failure. It becomes possible to efficiently obtain water on the surface of the titanium dioxide 4.

The air from which the ethylene E has been removed by the filter 3 as described above is discharged to the outside of the housing 1 through the exhaust port 1b by the operation of the blower fan 2.
The blower fan 2 creates a flow of air in a fixed direction in the cabinet 14 by sucking it from the intake port 1a in the housing 1 and discharging it from the exhaust port 1b, so that the entire air in the cabinet 14 is removed. It also has a function of diluting the concentration of ethylene to a large degree to circulate it, and to quickly separate the air having a high ethylene concentration released from the fresh agricultural product 15 from the fresh agricultural product 15 which is the generation source.

Next, the two types of ultraviolet arc tubes 5 and 6 used in the present invention will be described in detail.
As shown in FIGS. 2 and 3, each of the ultraviolet light emitting tubes 5 and 6 is arranged along the filter 3 at a distance of 20 mm to 30 mm from the surface 3a of the filter 3 on the air intake side. The ultraviolet light emitting tubes 5 are fixed in parallel with each other at intervals of 15 mm to 35 mm so as to be upright on the respective pedestals 12.
Both the central ultraviolet light emitting tube 5 capable of irradiating ultraviolet light of 254 nm wavelength and the ultraviolet light emitting tubes 6 on both sides thereof capable of irradiating ultraviolet light of wavelength 300 nm to 400 nm are elongated rod-shaped fluorescent lamp type ultraviolet light emitting tubes. can do.

Then, as shown in FIG. 2, in order to supply power to each of the ultraviolet light emitting tubes 5, the ultraviolet light emitting tubes 5 having a wavelength of 254 nm and the two ultraviolet light emitting tubes 6 having a wavelength of 300 nm to 400 nm are respectively used for the ultraviolet light tubes. The wiring 9 is provided, and the wiring 9 for the ultraviolet ray tube is connected to the power supply line 10.
Reference numeral 11 in FIG. 1 is a power distribution unit 11 that branches the motor wiring 8 of the blower fan 2 and the ultraviolet ray wiring 9 and connects them to each other.

Ultraviolet rays having a wavelength of 315 nm to 380 nm are called UV-A type, and those having a wavelength of 200 nm to 280 nm are called UV-C type, both of which are ultraviolet rays in different near ultraviolet regions. Ultraviolet rays have a strong chemical action and rapidly deteriorate the resin product in the apparatus, but UV-A type ultraviolet rays have a weak chemical action and have a weak power to deteriorate the resin product in the apparatus.
Note that VUV type ultraviolet rays having a wavelength in the deep ultraviolet region of 10 nm to 200 nm or less have a very strong chemical action, rapidly deteriorate the resin product in the apparatus, and generate ozone, so that they are not used in the present invention.
The UV arc tube 6 that emits UV-A type UV light of a fluorescent lamp type that is generally sold has a strongest peak at a wavelength of 370 nm, is attenuated before and after that, and has a width of 300 nm to 400 nm. It contains UV light of a wavelength and can be used.

In the present invention, the UV-A type ultraviolet ray emitting tube 6 having a wavelength of 300 nm to 400 nm has a power of 40 watts, whereas the UV-C type ultraviolet ray emitting tube 5 having a wavelength of 254 nm has a small wattage of 8 watts. Although a few ones are used, the chemical action of ultraviolet rays having a wavelength of 254 nm is stronger, and at a distance of 20 mm to 30 mm from the surface 3a on the air intake side of the filter 3, OH radicals are generated by irradiation with either ultraviolet ray arc tube. Is possible.

In the present invention, the ultraviolet light emitting tube 5 having a wavelength of 254 nm and the ultraviolet light emitting tube 6 having a wavelength of 300 nm to 400 nm have the following positional relationship in order to enable generation of OH radicals on the surface 3a of the filter 3.

Ultraviolet rays are rapidly weakened by water vapor in the air even in a short distance, and at a long distance of 30 mm or more, the filter 3 has almost no ability to generate OH radicals.
FIG. 7 is a graph showing that the irradiation degree of ultraviolet rays is rapidly attenuated by the irradiation distance of one ultraviolet ray emitting tube 5 having a wavelength of 254 nm.

As shown in the graph of FIG. 7, when the irradiation distance exceeds 5 cm, the ultraviolet irradiation degree suddenly weakens.
Then, when the irradiation distance exceeds 15 cm, the ultraviolet irradiation degree becomes almost equal to "0".
Therefore, in the present invention, the titanium dioxide 4 of the filter 3 is irradiated at a distance of 30 mm or less where an ultraviolet irradiation degree capable of generating OH radicals can be expected to be 0.8 or more.
However, if it is too close to 15 mm, the filter 3 is deteriorated by irradiation of ultraviolet rays, so the distance from the surface 3a of the filter 3 is set to 20 mm to 30 mm.
If the distance to the filter 3 is too close to the filter 3, ventilation may deteriorate at a portion of the filter 3 near the 254 nm ultraviolet light emitting tube 5, and therefore a position at which ventilation is not impaired. It is preferable to separate them.

Then, the ultraviolet ray emitting tubes 6 having a wavelength of 300 nm to 400 nm, which have a chemical action weaker than 254 nm, are provided on both sides of the ultraviolet ray emitting tube 5 having a wavelength of 254 nm at intervals of 15 mm to 35 mm, and the surfaces on the suction side of the filter 3 are both. It is installed in parallel at a position of 30 mm from 3a.
However, if the distances between the ultraviolet light emitting tubes 5 and 6 are so small that they are in contact with each other, the mutual gaps will be closed and the ventilation will be deteriorated.
Further, when the ultraviolet ray emitting tubes 5 and 6 are separated from each other by a large distance, a remote place where a chemical action due to the irradiation of the ultraviolet ray emitting tubes 5 and 6 with respect to the surface 3a of the filter 3 cannot be caused occurs. It was decided that the distance should be within 35 mm to the extent that

Since the ultraviolet ray emitting tube 5 having a wavelength of 254 nm, which has a large chemical action, is arranged in the center of the housing 1, the distance from the ultraviolet ray emitting tube 5 to surrounding parts is the tube of the ultraviolet ray emitting tube 6 having a wavelength of 300 nm to 400 nm. A distance of 45 mm or more, which is the sum of the diameter of 30 mm and the distance between the two of 15 mm, can be separated.
As shown in FIG. 7, this distance greatly exceeds the irradiation distance of 15 cm at which the ultraviolet irradiation degree becomes equal to “0”, and therefore is hardly affected by ultraviolet rays having a strong chemical action. It is possible to prevent shortening of life due to product deterioration.

With respect to the filter 3, in the plan view shown in FIG. 2, if the ultraviolet ray emitting tube 6 having a wavelength of 300 nm to 400 nm and the ultraviolet ray emitting tube 5 having a wavelength of 254 nm are arranged side by side by the same distance of 30 mm with respect to the surface 3a of the filter 3. As shown in FIG. 7, the UV irradiance is 0.8 at the shortest distance, and the surface of the filter 3 is located between the UV emission tube 6 having a wavelength of 300 nm to 400 nm and the UV emission tube 5 having a wavelength of 254 nm. In 3a, although the distance from each of the ultraviolet light emitting tubes 5 and 6 is large and the ultraviolet irradiation degree of each of the individual ultraviolet light emitting tubes 5 and 6 is lowered, the ultraviolet light having a wavelength of 300 nm to 400 nm and the ultraviolet light having a wavelength of 254 nm are overlapped and irradiated. In total, the ultraviolet irradiation degree of about 0.8 can be obtained.
As a result, almost the same degree of ultraviolet irradiation can be obtained on any part of the surface 3a of the filter 3.

Next, in the present invention, ethylene E in the air is brought into contact with OH radicals generated in the water on the surface of the titanium dioxide 4 by ultraviolet rays to modify harmless ethane e and water w. The principle will be explained.
Reference numeral E in FIG. 5 is ethylene, e is ethane, w is water, A is ultraviolet rays, F is a ventilation passage, 3 is a filter, and 4 is titanium dioxide particles.

As shown in FIG. 5, when the surface of titanium dioxide 4 is irradiated with ultraviolet rays A by ultraviolet ray emission tubes 5 and 6 having a wavelength of 254 nm or 300 nm to 400 nm, the energy of the ultraviolet rays A produces OH radicals from water molecules w.
At this time, the dissociation energy of “O” and “OH” is 4.8 eV, and the wavelength of the ultraviolet ray having this dissociation energy is λ=254 nm. Further, the dissociation energy in the ultraviolet light emitting tube 6 having a wavelength of λ=300 to 400 nm is 3.2 eV.
Then, the OH radical generated by being separated from water (H ₂ O) is bonded to ethylene (C ₂ H ₄ ).
The reaction of the OH radical with ethylene C ₂ H ₄ produces ethane (C ₂ H ₃ ) and water (H ₂ O).
This reaction is represented by the following chemical formula.

As described above, ethylene (C ₂ H ₄ ) is reformed into ethane (C ₂ H ₃ ) and water (H ₂ O), and the lifetime of OH radicals generated at that time is extremely 1/10 ⁶ seconds. It's the moment. However, in the present invention, as long as it is continuously irradiated with ultraviolet rays, it is continuously generated and OH radicals are always present in the water adhering to the surface of the titanium dioxide 4.

Furthermore, the surface of the titanium dioxide 4 has superhydrophilicity, and the water w in the air, the content of which changes depending on the change in humidity, is attached and becomes wet.
When the surface of the titanium dioxide 4 is irradiated with the ultraviolet rays A from the ultraviolet light emitting tubes 5 and 6, OH radicals are generated in the water w on the particle surface of the titanium dioxide 4 in the filter 3 by the photocatalytic action.
When the air sucked by the ventilation fan 2 flows from the intake port 1a to the water w on the surface of the particles of titanium dioxide 4 and ethylene E contained in the air comes into contact with the OH radicals on the surface of the titanium dioxide 4, ultraviolet irradiation is performed. Due to the energy and the photocatalytic action of titanium dioxide 4, ethylene E is effectively reformed into ethane e and water w.

In the present invention, the air containing ethylene E passes through the filter 3 and escapes. At that time, the titanium dioxide 4 exposed in the air passage F of the flat plate-shaped filter 3 has a large surface area and the air is narrow. Since it passes through the air passage F, the chance of contact of ethylene E in the air becomes large.
Further, at that time, the ultraviolet rays are simultaneously irradiated from one direction to the one ventilation path F by the three ultraviolet ray emitting tubes 5 and 6 from three directions, and further diffusely reflected to irradiate the inside of the ventilation path F on the light receiving surface side. Is possible.

At a position close to one ultraviolet arc tube, the filter 3 is strongly irradiated in a streak pattern, and irradiation from the other two streak parts is weak because it is at a distant position.
In addition, the filter 3 hits a position distant from any of the ultraviolet light emitting tubes at a position in the middle of the two ultraviolet light emitting tubes, so that the light is weakly irradiated, but at that position, the ultraviolet light emitting tubes on both sides are simultaneously irradiated, so that the total is total. Then it will be irradiated strongly.
Therefore, any position on the surface 3a of the ventilation filter 3 is simultaneously irradiated from the three ultraviolet light emitting tubes, and effective irradiation for generating OH radicals can be obtained at any position on the surface 3a of the filter 3. It will be.

When ultraviolet rays are emitted from the ultraviolet light emitting tubes 5 and 6, the ultraviolet rays travel through the ventilation passage F to excite the titanium dioxide 4 inside the filter 3 to reach the surface 3a of the filter 3 and the inside facing the ventilation passage F. OH radicals are generated in a wide range.
Then, in the present invention, a large amount of OH radicals are generated in the filter 3 by the ultraviolet irradiation energy and the photocatalytic action of the titanium dioxide 4, and ethylene E in the air comes into contact with the large amount of OH radicals. The ethylene E contained therein is surely reformed into ethane e and water w.

Although the principle of reforming ethylene E has been described above, the following modes are possible in the present invention.
For example, as shown in FIG. 6, in the vicinity of the surface 3a on the air intake side of each ultraviolet light emitting tube 5, 6, the outer peripheral surface on the air intake side is covered while avoiding the ventilation filter 3 side of each ultraviolet light emitting tube 5, 6. A form in which the reflection plate 13 is provided is possible.
In this mode, the ultraviolet rays emitted from the ventilation fans 2 of the ultraviolet ray emitting tubes 5 and 6 can be reflected and reflected toward the surface 3a of the ventilation filter 3, so that the irradiation efficiency of the ultraviolet rays is improved.

Further, as shown in FIG. 3, the central ultraviolet ray emitting tube 5 having a wavelength of 254 nm and the ultraviolet ray emitting tubes 6 on both sides thereof are set as one ultraviolet ray emitting tube unit U. A plurality of units U may be installed in one housing 1.
The apparatus shown in FIG. 1 shows a mode in which one ultraviolet light emitting tube unit U is used, but when it is used in a large storage cabinet or the like, in order to enhance the irradiation ability of ultraviolet rays, a plurality of units can be provided in one housing 1. This can be done by incorporating the ultraviolet arc tube unit U.

Next, examples of the present invention will be described.
As shown in FIGS. 1 and 2, the casing 1 is made of stainless steel having a length and width of 30 cm and a depth of 20 cm, and has a vertical and horizontal intake port 1a of 20 cm for sucking air into one side and a vertical and horizontal length of 20 cm for discharging the sucked air to the other side. A box-shaped one having an exhaust port 1b was used.
The propeller having a diameter of 10 cm was attached to the intake port 1a of the housing 1 and two blower fans 2 were attached to the top and bottom.
Further, a titanium dioxide 4 having a length and width of 20 cm and a thickness of 15 mm, which is exposed so as to be contactable with air, is provided on the side of the exhaust port 1b so as to block the ventilation passage that passes from the intake port 1a to the exhaust port 1b in the housing 1. The filter 3 on a flat plate which can be ventilated was arranged.

An ultraviolet ray emitting tube 5 capable of emitting ultraviolet rays having a wavelength of 254 nm is arranged along the surface 3a of the filter 3 on the air intake side in the center of the housing 1, and the wavelengths are provided on both sides of the ultraviolet ray emitting tube 5. The ultraviolet light emitting tube 6 capable of irradiating the ultraviolet light of was provided.
In order to obtain a certain degree of ultraviolet irradiation on the entire surface of the filter 3, the ultraviolet arc tubes are fluorescent lamp type ultraviolet arc tubes 5 and 6 having a length of 200 mm and a diameter of 30 mm. The wattage of the ultraviolet light emitting tubes 6 having wavelengths of 300 nm to 400 nm on both outer sides was 40 watts, and the ultraviolet light emitting tube 5 having a wavelength of 254 nm in the center was 8 watts.
Then, as shown in FIG. 4, the freshness preservation device of the present invention was hung on the ceiling in the refrigerator.

(Experimental example 1)
Injecting 130 ppm of ethylene into a 112-liter acrylic hermetically sealed container, which was likened to a cool box, and showing the time-dependent decay state of ethylene with and without the apparatus according to the first embodiment of the present invention. I observed.
The experimental results are shown in FIG.

In FIG. 8, “with device” is data obtained by putting the freshness preservation device of the present invention in a sealed container, and “without device” is data obtained without this device.
The amount of ethylene naturally decreased by 45 ppm in 25 minutes. It is considered that this is not due to the reforming of ethylene but was adsorbed on the wall surface or the like and reduced, but even after 60 minutes, 65 ppm of ethylene remains.
On the other hand, when the apparatus of the present invention was put in, ethylene was reduced by 130 ppm in 25 minutes.
This confirmed the excellent ethylene reforming effect of the device of the present invention.

In addition to vegetables and fruits, it is possible to use the freshness-preserving device for fresh agricultural products of the present invention in garden plants such as flowers.

1 Case 1a Intake port 1b Exhaust port 2 Blower fan 3 Filter 3a Surface of air intake side of filter 4 Titanium dioxide 5 Ultraviolet arc tube capable of irradiating ultraviolet ray of wavelength 254nm 6 Ultraviolet ray of wavelength 300nm to 400nm can be radiated Ultraviolet arc tube 7 Motor 8 Motor wiring 9 Ultraviolet tube wiring 10 Power supply line 11 Distribution section 12 Pedestal 13 Reflector 14 Storage 15 Fresh produce 16, 17 Protection filter E Ethylene e ethane w Water A Ultraviolet F Ventilation path S Storage space K Circulating air flow U Ultraviolet arc tube unit

Claims (4)

Installed in the warehouse to contact the OH radicals generated on the surface of titanium dioxide by UV irradiation and convert the harmful ethylene generated from the fresh agricultural products into harmless ethane and water to maintain the freshness of the fresh agricultural products for a long time. Is a mold freshness preservation device,
In the housing provided with one intake port that sucks air by the operation of the blower fan and the other exhaust port that discharges air,
A ventilated flat plate-like filter in which titanium dioxide is exposed so that it can come into contact with air is disposed so as to block a ventilation path that passes from the intake port to the exhaust port in the housing,
An ultraviolet arc tube capable of irradiating ultraviolet rays having a wavelength of 254 nm is arranged at a distance of 20 mm to 30 mm along the surface of the filter on the air intake side,
An ultraviolet light emitting tube capable of irradiating ultraviolet rays having a wavelength of 300 nm to 400 nm in parallel at a distance of 20 mm to 30 mm from the surface of the air suction side of the filter at a distance of 15 mm to 35 mm from the ultraviolet light emitting tube and having a wavelength of 254 nm A freshness-maintaining device for fresh agricultural products, characterized in that one is provided on each side of the ultraviolet ray emitting tube capable of irradiating ultraviolet rays . An ultraviolet arc tube capable of irradiating an ultraviolet ray having a wavelength of 254 nm in the center and an ultraviolet arc tube capable of irradiating ultraviolet rays having a wavelength of 300 nm to 400 nm on both sides thereof are defined as one unit of the ultraviolet arc tube unit. The freshness preservation device for fresh agricultural products according to claim 1, wherein a plurality of the freshness preservation devices are installed in one housing. 3. The freshness-keeping device for fresh produce according to claim 1, wherein a reflector plate is provided in the vicinity of the air suction side of each ultraviolet light emission tube to cover the outer peripheral surface of each ultraviolet light emission tube on the air intake side. The freshness-retaining device for fresh produce according to any one of claims 1 to 3, wherein a protective filter is provided at the exhaust port and the intake port of the housing to block the opening so that the opening can be ventilated.

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