JP3564604B2 - Freshness keeping device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for maintaining freshness of fruits and vegetables.
[0002]
[Prior art]
BACKGROUND ART Conventionally, when storing fruits and vegetables, it is known that the fruits and vegetables ripen and age due to ethylene and the like generated from the fruits and vegetables themselves. For this reason, various techniques for removing ethylene have been proposed. For example, a freshness preserving agent using PdCl, a technology for removing ethylene using a photocatalyst, a technology for oxidizing ethylene with ozone, and the like have been proposed.
[0003]
[Problems to be solved by the invention]
However, the above-mentioned freshness preserving agent is a chemical adsorbent, and its use time is greatly deteriorated with time. In addition, when attempting to remove ethylene with a photocatalyst, an adsorbent for efficiently physically adsorbing ethylene to the catalyst has not been found yet, and the efficiency is low.
[0004]
Oxidation of ethylene with ozone generates ethylene oxidation products such as formic acid, acetic acid, and formaldehyde. Then, even if an ozone decomposition catalyst using activated carbon as a carrier is used to remove the ozone remaining without being consumed by the oxidation of ethylene, the ethylene oxidation product becomes a catalyst poison for the ozone decomposition catalyst. Therefore, the performance of the ozone decomposition catalyst is degraded, and its replacement is frequently performed.
[0005]
The present invention has been made in view of such circumstances, and provides a freshness preserving technique capable of efficiently removing ethylene and the like and further efficiently removing remaining ozone.
[0006]
[Means for Solving the Problems]
Which according to the inventions is an oxidation means for generating ozone (11), wherein the oxidation product removal means for removing the resulting oxidized product by an oxidation means (12), the ozone removing means for removing the ozone and (13), Ru comprising said via oxidation product removal means (12) ozone removal means to (13) and a transport means for moving the gas to be treated (14) from said oxidizing means (11) freshness It is a holding device.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
First embodiment.
FIG. 1 is a diagram schematically showing a structure of a freshness holding device 100 according to a first embodiment of the present invention. The freshness holding device has roughly four functions. The first function is the oxidative decomposition of ethylene by the ozone generation means 11, the second function is the decomposition of ethylene oxidation products by the photocatalyst unit 12, and the third function is the photocatalyst from the ozone generation means 11 by the fan unit 14. The fourth function is to remove the remaining ozone by the ozone decomposition catalyst 13 by moving the gas to be treated to the ozone decomposition catalyst 13 via the unit 12.
[0019]
First, the first function will be described. The ozone generating means 11 generates ozone from oxygen molecules. The ozone generation means 11 may have a configuration for generating ozone by using, for example, silent discharge. Ozone O ₃ generated by the silent discharge oxidizes and decomposes ethylene H ₂ C ＝ CH ₂ to produce formic acid, acetic acid, and formaldehyde COH ₂ as ethylene oxidation products.
[0020]
Further, the ozone generating means 11 may have a configuration for generating ozone using, for example, ultraviolet light. For example, ozone can be generated by photoexcitation by irradiating oxygen molecules with ultraviolet light having a wavelength of 184.9 nm. During the generation of ozone, active oxygen is also generated, which also oxidizes and decomposes ethylene to produce, for example, formic acid, acetic acid, and formaldehyde as ethylene oxidation products.
[0021]
Further, for example, by irradiating ozone with ultraviolet light having a wavelength of 253.7 nm, ozone is decomposed by photoexcitation to obtain oxygen molecules. During the ozonolysis, active oxygen is also generated, which also oxidizes and decomposes ethylene to produce, for example, formic acid, acetic acid, and formaldehyde as ethylene oxidation products.
[0022]
Therefore, the ozone generating means 11 may be configured using a lamp that generates both ultraviolet light having a wavelength of 184.9 nm and ultraviolet light having a wavelength of 253.7 nm. Alternatively, as shown in FIG. 2, ozone is generated by a silent discharge mechanism 11a, and a so-called germicidal lamp 11b can be employed as a source of ultraviolet light having a wavelength of 253.7 nm.
[0023]
Next, the second function will be described. The photocatalytic unit 12 includes a photocatalytic substance and a light source that irradiates the photocatalytic substance to make the catalytic action remarkable. As the photocatalytic substance, for example, titanium oxide TiO ₂ , strontium titanate SrTiO ₃ , potassium niobate K ₄ NbO ₁₇ , niobium oxide NbO ₅ , tungsten oxide WO _3, and zinc oxide ZnO can be used. For example, an ultraviolet lamp that emits ultraviolet light having a wavelength of 400 nm or less, for example, 365 nm can be used. The photocatalyst unit 12 decomposes ethylene oxidation products such as formic acid, acetic acid, and formaldehyde into carbon dioxide CO ₂ and water H ₂ O.
[0024]
Next, the third function will be described. The fan unit 14 includes a fan for transferring the gas to be processed in the directions 21 and 22 indicated by white arrows in FIG. The freshness maintaining device 100 has an inlet 18 and an outlet 19, and the gas to be treated is sucked into the inlet 18 according to the direction 21 and sent out from the outlet 19 according to the direction 22.
[0025]
Therefore, the ethylene oxidation product generated in the ozone generation means 11 is sent to the photocatalyst unit 12 without remaining in the ozone generation means 11, so that the ethylene oxidation products, for example, formic acid, acetic acid, and formaldehyde are efficiently transferred to the photocatalyst unit 12. Can be supplied to remove it.
[0026]
Next, the fourth function will be described. The ozone decomposition catalyst 13 removes the ozone generated by the ozone generating means 11 and not consumed and remaining. Therefore, as the gas to be processed, which is sent out from the outlet 19 in the direction 22, a gas having a low concentration of both ethylene and ozone can be supplied.
[0027]
As described in relation to the related art, a catalyst using activated carbon as a carrier can be employed as the ozone decomposition catalyst 13. Even in such a case, the ethylene oxidation product which is a catalyst poison for the ozone decomposition catalyst 13 is removed by the photocatalyst unit 12, so that the deterioration of the performance of the ozone decomposition catalyst 13 is suppressed, and replacement of the ozone decomposition catalyst 13 becomes frequent. Can be avoided. In order to obtain such an effect, it is desirable that the gas to be treated is transferred from the photocatalyst unit 12 to the ozone decomposition catalyst 13 by the fan unit 14.
[0028]
The fan unit 14 may be arranged anywhere as long as the gas to be treated can be transferred in the order of the ozone generating means 11, the photocatalyst unit 12, and the ozone decomposition catalyst 13. However, since it is exposed to the gas to be processed, the position where the concentration of ozone, ethylene, or the like is low, that is, as shown in FIG. It is desirable to be arranged at a close position.
[0029]
Further, the ultraviolet light irradiated by the ozone generating means 11 may also be used as the ultraviolet light irradiated to the photocatalyst by the photocatalyst unit 12.
[0030]
Since the gas to be treated obtained from the outlet 19 of the freshness maintaining apparatus 100 in this manner has ethylene removed, the ripening and aging of the fruits and vegetables are reduced. Therefore, by using the freshness holding device 100, the freshness of the fruits and vegetables can be held. Such a freshness maintaining device 100 can be used not only for home and commercial refrigerators but also for refrigerated containers and the like.
[0031]
Second embodiment.
In some cases, it is not always necessary to remove excess ozone from the gas supplied to the fruits and vegetables for maintaining freshness. This is because, for example, during the period during which the fruits and vegetables are stored, spraying a low concentration of ozone on the fruits and vegetables can suppress the generation of microorganisms. FIG. 3 is a diagram schematically showing the structure of a freshness holding device 200 according to the second embodiment of the present invention, which has been made in view of such circumstances.
[0032]
The freshness holding device 200 includes a main path 4a and a bypass path 4b. The main path 4a has an inlet 18 and an outlet 19a, and a bypass path 4b branches between them. The bypass passage 4b has an outlet 19b, and the bypass passage 4b is provided with a valve 30 near the branch from the main passage 4a.
[0033]
In the main path 4a, between the inlet 18 and the branch to the bypass path 4b, the ozone generating means 11, the photocatalyst unit 12, and the fan unit 14 are arranged in this order. An ozone decomposition catalyst 13 is further disposed on the main path 4a between the branch to the bypass path 4b and the outlet 19a.
[0034]
In this freshness maintaining device 200, if the valve 30 is closed so that the gas to be processed is not diverted to the bypass path 4b, the same effect as in the first embodiment can be obtained. That is, the gas to be treated is transported in the order of the ozone generating means 11, the photocatalyst unit 12, and the ozone decomposition catalyst 13, and is sent out from the outlet 19a in the direction 22a.
[0035]
On the other hand, when the valve 30 is opened, the gas to be treated is diverted also to the bypass path 4b and is sent out from the outlet 19b in the direction 22b. Since the gas to be processed sent from the outlet 19b does not pass through the ozone decomposition catalyst 13, it is generated by the ozone generating means 11 and contains the remaining ozone without being consumed. Therefore, it is possible to supply a gas that can suppress the generation of microorganisms while maintaining the freshness of the fruits and vegetables.
[0036]
In the present embodiment, the valve 30 is simply provided in the bypass passage 4b. However, a three-way valve that sends out the gas to be processed to only one of the outlets 19a and 19b may be provided. Further, the fan units 14 may be provided separately near the outlets 19a and 19b.
[0037]
Deformation.
Means for removing ethylene oxidation products generated by the oxidative decomposition of ethylene by ozone, for example, formic acid, acetic acid, and formaldehyde, that is, oxidation product removal means, a thermal catalyst other than the photocatalyst unit 12 described above, Chemical adsorbents can be employed.
[0038]
In addition, as shown in FIG. 4, when ethylene oxidation products such as formic acid, acetic acid, and formaldehyde are transported as indicated by an arrow 23, the sheet 15a facing this has a function of removing the oxidation products. May be. Here, the case where the oxidation product is transported almost vertically to the sheet 15a is shown, but the oxidation product may be transported obliquely at an angle. However, when the oxidation product is transported almost perpendicularly to the sheet 15a, it is desirable that the sheet 15a has good ventilation.
[0039]
The sheet 15a is wound in a roll shape on a delivery reel 15b, and is wound on the take-up reel 15c in a roll shape. The sheet 15a is exposed to oxidation products between the sending reel 15b and the take-up reel 15c. If the performance of the sheet 15a is deteriorated, the sheet 15a is sequentially exposed to an oxidized product from the sending reel 15b, and the deteriorated sheet 15a is taken up on the take-up reel 15c. It is possible to avoid a decrease in the ability to remove objects.
[0040]
Of course, when the sheet 15a performs a photocatalytic function, it is necessary to irradiate a predetermined light 17 by a light source, for example, an ultraviolet lamp 16, but when the sheet 15a is a heat catalyst or a chemical adsorbent, the light source is Not required.
[0041]
【The invention's effect】
According to the freshness retaining device according to this inventions, an ethylene oxide product Oite ethylene oxide unit has occurred is oxidative decomposition is delivered to the oxidation product removal means without staying in oxidation means, remaining ozone since is removed, ethylene, Ru can supply any concentration even low gas ozone.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a structure of a freshness holding device according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of an ozone generating unit 11;
FIG. 3 is a diagram schematically showing a structure of a freshness holding device according to a second embodiment of the present invention.
FIG. 4 is a diagram schematically showing a modified configuration of the present invention.
[Explanation of symbols]
11 Ozone generating means 11a Silent discharge mechanism 11b Sterilizing lamp 12 Photocatalytic unit 13 Ozone decomposition catalyst 14 Fan unit 15 Oxidation product removing means

Claims (1)

Oxidizing means (11) for generating ozone;
Oxidation product removal means (12) for removing oxidation products obtained by the oxidation means ;
Ozone removing means (13) for removing the ozone;
Transfer means (14) for moving the gas to be treated from the oxidizing means (11) to the ozone removing means (13) via the oxidation product removing means (12);
A freshness holding device comprising:

Images