JPH09140328A - Electrode for emitting negative electron and apparatus for retaining freshness of fresh plant using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both an electrode for emitting negative electrons capable of affording a high discharge efficiency under the same application conditions without any complicatedness in production and an apparatus for retaining the freshness of a fresh plant capable of imparting freshness retaining actions thereof for a relatively long period when storing, preserving and transporting the fresh plant just after harvesting such as an edible agricultural product or a natural flower. SOLUTION: This electrode 1 for emitting negative electrons comprises a substrate having the substantially square front and back surfaces mainly composed of a porous material of aluminum or an aluminum alloy and provided with aluminum whiskers in at least a part of the substrate. Furthermore, the apparatus for retaining the freshness of a fresh plant is equipped with a catalyst 10 for adsorbing and decomposing ethylene and the electrode 1 for emitting the negative electrons connected to an electrical application means in an apparatus body 2 having an introduction port 3 and a discharge port 4 for air. The apparatus is capable of introducing the air from the introduction port 3, mixing the negative electrons emitted from the electrode 1 for emitting the negative electrons in the introduced air, discharging the resultant air from the discharge port 4 and bringing the discharged air into contact with the fresh plant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anion emitting electrode and a freshness-preserving apparatus for fresh plants using the same, and more specifically, it has high production efficiency under the same application condition without complication in production. The present invention relates to an anion emitting electrode, and to a freshness-maintaining device capable of imparting a freshness-maintaining action for a relatively long period during storage, storage and transportation of freshly harvested fresh plants such as edible agricultural products and ikebana.

[0002]

2. Description of the Related Art Conventionally, an anion emitting electrode has been used in an air purifier or the like, but a potential of minus several hundreds to tens of thousands of volts is emitted to a casing or a base. As such a conventional electrode, a thin wire electrode is known which uses a solid conductive material such as copper, aluminum or steel.
However, since the discharge efficiency is not sufficient, attempts have been made to reduce the polar radius of the tip that emits electrons, and a nib-shaped electrode having a sharpened tip like an nib is used. Since such a nib-shaped electrode still has insufficient discharge efficiency, small projections are attached to a thin plate in a saw-tooth shape, or a saw-toothed electrode is also considered.

However, the precise saw blade molding is very complicated to manufacture, which causes a cost increase.

Therefore, the present inventor has continued research on an anion emission electrode capable of obtaining a high discharge efficiency under the same applied condition in order to realize cost reduction without manufacturing complexity, and alumina whiskers It was found that the above-mentioned problems can be solved by using a plate-shaped electrode having a.

On the other hand, the present inventor has conducted extensive research on the use of an anion emitting electrode using alumina whiskers, and as a result, good results have been obtained when applied to a freshness preservation device for fresh plants. The present invention has been made and the present invention has been achieved.

[0006]

Therefore, the first aspect of the present invention
It is an object of the present invention to provide an electrode for negative electron emission that does not require complicated manufacturing and that can achieve high discharge efficiency under the same application conditions. A second object of the present invention is to provide a technique for applying the above-mentioned anion emission electrode to a freshness preservation device for fresh plants. A third object of the present invention is to provide a fresh plant freshness-maintaining device capable of imparting a freshness-maintaining action for a relatively long period during storage, storage and transportation of freshly harvested fresh plants such as edible agricultural products and ikebana. To provide.

[0007]

In the anion emission electrode according to the present invention for solving the above-mentioned first problem, the substrate having substantially square front and back surfaces is a porous body of aluminum or aluminum alloy. It is characterized in that it is mainly constituted and has alumina whiskers on at least a part of the base material.

The first freshness-retaining device for fresh plants according to the present invention, which solves the above-mentioned second and third problems, is connected to an electric application means in the device main body having an air inlet and an air outlet. A fresh plant by introducing an anion electron emission electrode, introducing air from the introduction port, mixing anion electrons emitted from the anion electron emission electrode into the introduction air, and discharging from the discharge port. A device for maintaining the freshness of fresh plants by contacting with, the anion emission electrode, the substrate having a substantially square front and back is mainly constituted by a porous body of aluminum or aluminum alloy, At least a part of the base material has alumina whiskers.

In a preferred embodiment of the present invention, a fan for introducing air from the air inlet and discharging the air from the outlet is provided in the apparatus body.

A second freshness-retaining device for fresh plants according to the present invention is a device in which an ethylene adsorption decomposition catalyst having alumina whiskers is added to the first freshness-retaining device.

In a preferred embodiment of the present invention, the ethylene adsorption decomposition catalyst continuously grows fine needle-like or bamboo leaf-like crystals of alumina (Al ₂ O ₃ ) from a base material made of aluminum or an aluminum alloy. It is to have an alumina whisker, and in a more preferable embodiment, the base material made of aluminum or an aluminum alloy that constitutes the ethylene adsorption decomposition catalyst is at least an aluminum porous sintered body, an aluminum fiber aggregate or an aluminum foam. 1
The specific surface area of the base material made of aluminum or an aluminum alloy that constitutes the ethylene adsorption decomposition catalyst is 0.5 to ²⁰ m ² / g.

[0012] In another preferred embodiment of the present invention,
A fan that introduces air from the air inlet and discharges it from the outlet is provided inside the apparatus main body, and a part or all of the blades of the fan is configured by an ethylene adsorption decomposition catalyst having alumina whiskers.

Conventionally, Japanese Unexamined Patent Publication No. 1-225375 describes a technique of using a tetrapot-shaped zinc oxide whisker for a photoconductive element, and Japanese Unexamined Patent Publication No. 1-299453 discloses a metal thin wire having whiskers of carbon, silicon and tungsten. A mass spectrometer using the above is described, and JP-A-3-200315 describes a solid electrolytic capacitor using an aluminum tab in which whisker-like aluminum hydroxide is formed on the aluminum surface as an anode. Whiskers are not used as an electrode for anion emission, and there is no description suggesting that. Further, Japanese Patent Application Laid-Open No. 4-87233 describes a technique in which a tetrapod-shaped zinc oxide whisker is used for an emitter electrode, but does not describe an alumina whisker. Further, Japanese Patent Laid-Open No. 6-150881 describes a technique using alumina whiskers, but it uses an emitter material (alkaline earth metal) for electron emission, and alumina whiskers are used to exert an anchor effect. However, only metal wires are used for the electrodes, which does not suggest the present invention.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The base material used for the anion emission electrode of the present invention has a substantially square front and back surface. Specifically, as shown in FIG. The base material of the electrode 1 is preferably a rectangular thin plate, for example, 200 mm x 10 m
For example, m × 2.5 mm (thickness) can be used.

Alumina whiskers can be manufactured from a pure aluminum base material, but can also be manufactured from an aluminum alloy base material. Aluminum alloys include strengthening elements and corrosion resistant elements such as Cu, Zn, Mg, Mn, Ti and Si.
Aluminum alloys containing less than 50% by weight are used. Alumina whiskers are a known hydrothermal treatment of porous sintered plates of aluminum or aluminum alloy in the atmosphere and in the atmosphere, for example, 15
It can be produced by heat treatment at 0 ° C.

Since the electrode of the present invention has substantially rectangular front and back surfaces, it does not require precise processing,
In addition, the fine alumina whiskers themselves become discharge electrodes with a small radius of curvature, and have numerous projecting electrodes over the entire surface of the porous body that is clustered together, making the electron emission more effective. ing.

Applications of the electrode of the present invention include, but are not limited to, freshness preservation of fresh plants and air cleaning. Conventionally, it has been attempted to apply a so-called negative electron generator that emits negative electrons into the air to be applied to agricultural product warehouses and commercial refrigerators. The relationship between the freshness-maintaining action of perishables and the released anion electrons has not been theoretically elucidated, but the practical effects are exhibited. The present inventor presumes that the anion emission causes water in the air to have a low oxidative state. Generally, when an electron is charged into water, the oxidation-reduction potential of water decreases, and it reaches the reduction side in some cases. When the redox potential of water is high, substances that come into contact with it are easily oxidized, and in organic matter, progress of decay is observed. If the redox potential is small, the oxidation is unlikely to occur. For example, tap water has a potential of +500 to +700 mV,
If an anion is introduced into this by electrical means, +100 to -500 mV
It changes to a degree. Although there is no way to measure the oxidation-reduction potential of water contained in the air, it is considered that the same behavior is exhibited, and the freshness-retaining action due to the emission of anion into the air as described above is estimated.

Next, an embodiment of the freshness preservation apparatus for fresh plants according to the present invention will be described with reference to FIG.

In FIG. 2, reference numeral 2 is a main body of the apparatus, and its shape, size, etc. are not limited. Reference numeral 3 is an air inlet provided in the main body 2, and 4 is an outlet. Reference numeral 5 denotes a fan that mixes the anions emitted from the anion emission electrode 1 into the air introduced from the inlet 3 and discharges them from the outlet 4. The fan 5 may be provided in the device body, but is not necessarily limited thereto. The fan is preferably a sirocco fan. This is because compared to other axial flow fans, vane pumps, and piston blowers, a large amount of air can be obtained with low noise.
When forming a large-sized freshness preservation device, various blowers and the like can be used.

The negative electron emitting electrode 1 is provided in the apparatus main body 2 and is connected to an electric applying means. As an electric application means, an A / D converter 6 for changing an alternating current into a direct current as shown in the figure, a control unit 7 for dividing the direct current into positive and negative currents, a positron applying unit 8 and a negative electron applying unit 9 Composed by. Such electrical applying means may be installed in the apparatus main body 2, but need not be provided if it can be applied from the outside.

The first freshness preservation device of the present invention can be constituted by the anion emission electrode 1 and the fan 5 described above. The reason why freshness can be maintained by the anions emitted from the anion emitting electrode 1 has been described above. The voltage applied to the negative electrode emitting electrode 1 is preferably -500 to -15000v, more preferably -5000 to -10000v. As the anion emission electrode 1, the above electrode of the present invention can be used, and for example, the one shown in FIG. 1 can be used.

Next, the second freshness preservation device of the present invention will be described.

This apparatus is the same as the above-mentioned first freshness-keeping apparatus, except that an ethylene adsorption decomposition catalyst having alumina whiskers is used.
It is a device with 10 added.

[0024] Fresh plants are generally kept in cold air in a low-temperature environment or in an environment where moisture is adjusted. However, ethylene gas released from fresh plants is not only self-degraded in the released agricultural products themselves, but also stored adjacently. It also promotes product degradation. There is almost no industrial means for discharging ethylene, and therefore, promoting natural ventilation of ethylene gas causes a problem that cold air or water in a low temperature environment also escapes.
The present invention provides means for directly adsorbing and decomposing this ethylene gas.

Further, by combining the above-mentioned anion emission electrode 1 and the ethylene adsorption decomposition catalyst 10, not only the function of the ethylene adsorption decomposition catalyst 10 but also ethylene (C ₂ H) _{It is considered that 4} ) may change its molecular structure under abundant anion environment.

In the present invention, the ethylene adsorption decomposition catalyst is an alumina whisker in which needle-like or bamboo leaf-like crystals of fine alumina (Al ₂ O ₃ ) are continuously grown from a base material made of aluminum or an aluminum alloy. Those that have are used.

Crystal growth of alumina whiskers is carried out by immersing in alumina deionized water for a long time to form an ultra-thin layer of Al ₂ O ₃ .xH ₂ O (boehmite) on the outermost layer of aluminum or aluminum alloy and then heating. By dehydrating the water content by the treatment, alumina whiskers that continuously extend from the base material are industrially produced. It is preferable to use a porous aluminum sintered body manufactured by a powder metallurgical method as a base material for generating whiskers in order to promote an adsorption decomposition action of ethylene, but an aluminum fiber aggregate or an aluminum foam is used. You can also

The specific surface area of the base material made of aluminum or aluminum alloy constituting the ethylene adsorption decomposition catalyst is preferably 0.5 to ²⁰ m ² / g (nitrogen gas adsorption method). The specific surface area is defined by the nitrogen gas adsorption method, and the sample is formed by sintering aluminum powder having an average particle size of 200 μm and using a base material having a porosity of about 45%, and the entire surface including the porosity. It is a cluster of alumina whiskers. Alumina whiskers can be manufactured from a pure aluminum base material, but can also be manufactured from an aluminum alloy base material. Aluminum alloys include strengthening elements and corrosion resistant elements such as Cu, Zn, Mg, Mn, Ti and Si.
Aluminum alloys containing less than 50% by weight are used.

In the present invention, a plurality of negative electron beams connected to the electric applying means are connected to the second freshness preservation device.
It is also preferable to add 11.

By using the negative electron beam 11 in addition to the negative electron emitting electrode 1, it is possible to further increase the negative ions. Further, by positively charging the catalyst 10, it is possible to negatively charge the odorant molecules and at the same time, to electrodeposit and adhere to the layer of the catalyst 10 having a positive potential, thereby increasing the efficiency of removing the odorant molecules. Since the catalyst 10 used in the present invention is a base material made of aluminum or an aluminum alloy, it is possible to positively energize as shown in FIG. The above-mentioned applying means can be used as the electrical applying means. The number of negative electron beams is not particularly limited.

In the present invention, in the above embodiment, it is preferable that a part or all of the blade portion of the fan 5 is composed of the ethylene adsorption decomposition catalyst having the above-mentioned alumina whiskers. This is to further enhance the contact efficiency with ethylene in the inflowing air. In addition, the fan and catalyst can be integrated to make the entire device compact.

In the above embodiment, adsorbents such as activated carbon and zeolite can be arranged before and after the catalyst 10, and these adsorbents can be arranged between the laminated structures of the catalyst 10.

[0033]

Embodiments of the present invention will be described below.

Example 1 A 200 mmL × 10 mmW × 2.5 mmt aluminum-based porous sintered plate as shown in FIG. 1 was subjected to hydrothermal treatment and heat treatment at 150 ° C. in the atmosphere, and the entire surface including voids of the plate was alumina. An electrode was produced in which whiskers were clustered. The electrode was attached to a housing, a high-voltage negative potential was applied, and the potential released from the electrode was measured using a non-contact type electric field measuring device (Stachiron M2 type manufactured by Shishido Electrostatic Co., Ltd.). As a result, the results shown in Table 1 were obtained. As a comparative example, a nib-shaped electrode (made of copper) having a shape as shown in FIG. 4 and a thickness of 1 mm was applied and measured in the same manner as in Example 1. Table 1 shows the results.

[0035]

[Table 1]

As is clear from Table 1, the electrode of the present invention has a substantial discharge efficiency increase of 50 to 90% for the same applied voltage as compared with the comparative electrode. This increase in efficiency is due to the fact that the electrode of the present invention emits anions over the entire length of the long side and is a planar emission as compared with the point emission of the comparative electrode.

Example 2 The discharge device equipped with the electrode of the present invention obtained in Example 1 was placed in a 500 liter closed chamber containing strawberries, and anion emission of −5000 V was conducted for 5 days at room temperature. went. As a result, there was no deterioration of the strawberry. Further, the ethylene concentration in the chamber after 5 days was not detected.
On the other hand, for comparison, the same experiment was performed in the same chamber without anion emission. As a result, room temperature 5
In the one-day experiment, strawberry was found to have mildew from about the 3rd day, and on the 5th day, about 50% of the surface was covered with mildew. The relative humidity in the chamber was 60 to 70% in both experiments of the present invention and the comparison.

Example 3 Using the freshness preservation device shown in FIG. 2, the freshness preservation effect of fresh plants was confirmed. The ethylene gas adsorption decomposition catalyst 10 is 200 mm x 50 mm x 2.5 mm as a catalyst material with Asmina whiskers.
A plurality of (thickness) slit cutting materials were used to form a 7-layer laminated structure with uniform air distribution so that the air circulation space 10A was 5 mm. In addition, the slit laminated type catalyst is integrally incorporated in the main body 2 as a unit so that the whole catalyst can be replaced. The negative electrode emitting electrode 1 used was the one manufactured in Example 1. The applied potential was set to -7000V. The sirocco fan 5 is placed closer to the outlet 4 as shown in the figure, and has an outer diameter of 50 m.
m, 200 mm in length was used, and the rotation speed was 1000 rpm.
Since the negative electron beam 11 was additionally provided, it was not discharged in this experiment. An experiment was conducted under the above conditions, and the removal performance of ethylene gas was examined as follows. Ethylene gas was charged in a closed chamber of 1 m ³ in which the apparatus of the present invention was placed at 33 ppm, and the inside of the chamber was uniformly convected and stirred. The apparatus was operated in this state and the amount of ethylene gas reduction was confirmed. For comparison, an experiment was also conducted with time when the apparatus in the chamber was not operated, that is, with respect to the natural attenuation of ethylene gas. The result is shown in FIG.

As is apparent from FIG. 3, when the apparatus of the present invention was operated, the residual concentration of ethylene gas was 3 on the second day.
It was less than one-third, which was close to zero on the 4th day, and ethylene gas was not detected on the 5th day. On the other hand, by comparison, two-thirds of ethylene gas remained on the fifth day.

Next, the agricultural products were stored in a freshness-maintaining chamber of 2 tsubo and stored at 5 ° C. and a relative humidity of 85%, and the freshness-retaining effect of the agricultural products was confirmed using this apparatus. Further, the same was confirmed for a comparative example not using this device. Table 2 shows the results.

[0041]

[Table 2]

[0042]

According to the present invention, it is possible to provide an electrode for negative electron emission which does not require complicated manufacturing and which can obtain high discharge efficiency under the same application conditions. Further, it is possible to provide a technique of applying the above-mentioned anion emission electrode to a freshness preservation device for fresh plants. Further, according to the present invention, it is possible to provide a freshness-preserving device for a fresh plant capable of imparting a freshness-maintaining action for a relatively long period during storage, storage and transportation of a freshly harvested fresh plant such as edible agricultural products and ikebana. You can

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an embodiment of the present invention.

FIG. 3 is a graph showing a change in ethylene gas concentration with respect to the number of days elapsed.

FIG. 4 is a side view showing a conventional example.

[Explanation of symbols]

 1: Electrode for anion electron emission 2: Device body 3: Inlet port 4: Discharge port 5: Fan 6: Conversion device 7: Control unit 8: Positron application unit 9: Anion electron application unit 10: Catalyst 10A: Air flow space 11 : Negative electron beam

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C01F 7/00 C01F 7/00

Claims (8)

[Claims] 1. A negative electron characterized in that a base material having substantially rectangular front and back surfaces is mainly composed of a porous body of aluminum or an aluminum alloy, and at least a part of the base material has alumina whiskers. Emission electrode. 2. An anion electron emission electrode connected to an electric application means is provided in an apparatus main body having an air introduction port and an air emission port, and air is introduced from the introduction port and the anion electron emission is performed. A device for mixing the anion emitted from the electrode for use in the introduced air and discharging from the outlet to contact fresh plants to maintain the freshness of the fresh plants, wherein the anion emitting electrode comprises: A freshness-preserving device for fresh plants, characterized in that a substrate having substantially square front and back surfaces is mainly constituted by a porous body of aluminum or an aluminum alloy, and alumina whiskers are provided on at least a part of the substrate. 3. The freshness-keeping device for fresh plants according to claim 2, wherein a fan for introducing air from an air inlet and discharging the air from the outlet is provided in the main body of the device. 4. An ethylene adsorbing and decomposing catalyst having alumina whiskers and an anion emitting electrode connected to an electric applying means are provided in an apparatus main body having an air inlet and an air outlet. An apparatus for maintaining freshness of fresh plants by introducing more air and mixing the anions emitted from the anion emitting electrode with the introduced air and discharging from the outlet to contact fresh plants. In the anion emission electrode, the base material having substantially rectangular front and back surfaces is mainly composed of a porous body of aluminum or aluminum alloy, and at least a part of the base material has alumina whiskers. A freshness preservation device featuring fresh plants. 5. An ethylene adsorption decomposition catalyst having an alumina whisker in which needle-like or bamboo leaf-like crystals of fine alumina (Al ₂ O ₃ ) are continuously grown from a base material made of aluminum or an aluminum alloy. The freshness preservation device for fresh plants according to claim 4, wherein the freshness preservation device is provided. 6. A substrate comprising aluminum or an aluminum alloy which constitutes the ethylene adsorption decomposition catalyst is at least one of an aluminum porous sintered body, an aluminum fiber aggregate or an aluminum foam. A freshness preservation device for the fresh plant described. 7. The specific surface area of a base material made of aluminum or an aluminum alloy, which constitutes the ethylene adsorption decomposition catalyst,
The freshness-retaining device for fresh plants according to claim 5 or 6, characterized in that the freshness is 0.5 to ²⁰ m ² / g. 8. A fan for introducing air from an air inlet and discharging it from an outlet is provided in the main body of the apparatus, and a part or all of a blade portion of the fan is constituted by an ethylene adsorption decomposition catalyst having alumina whiskers. The freshness preservation device for fresh plants according to claim 4, 5, 6, or 7.