JP3761302B2 - Method and apparatus for removing fungi in the air - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the removal of fungi in the air, and in particular, a method for removing (sterilizing and sterilizing) fungi in spaces where fungi in the air are problematic in hospitals, food factories, department stores, pharmaceutical factories, general households, and the like. Relates to the device.
[0002]
[Prior art]
As a conventional space cleaning technique, an air cleaner in a hospital will be described as an example.
The air purifier forcibly vents particulate matter (including fungi) by a filtration filter, a collection unit for odorous substances by activated carbon (fibrous), and air to be treated to the collection unit. It was made up of fans.
In such a configuration, the fungi are collected on the filter, but are not sterilized (sterilized) on the filter, so there are problems such as growth of fungi on the filter and outflow to the rear. However, it was a problem in the technical field.
Further, although a sterilization (sterilization) apparatus using ozone has been proposed, since ozone is harmful to the human body (living body), its use is limited and has been a problem.
In this way, the current air cleaning system is a filter-like or fibrous filtration mechanism, so there are problems such as proliferation due to adhesion of fungi on the surface, outflow to the rear, and generated ozone, There was also a problem of noise generation by fans.
[0003]
[Problems to be solved by the invention]
Then, this invention makes it a subject to solve the problem of the said prior art and to provide the method and apparatus which can collect and disinfect bacteria in the air effectively.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the present invention, in a method for removing fungi in the air without charging, the air to be sterilized is provided in a net-like or linear shape where a sterilization line is irradiated. This is a method for removing fungi in the air, which is characterized by passing through an electrode to which an electric field of / cm is applied.
Moreover, in this invention, in the apparatus which removes the fungi in air, without being charged, the electrode by which the electric field of 500-3000 V / cm of a mesh | network or a line | wire was given in the flow path which lets air which should be disinfected The device for removing fungi in the air is characterized in that a germicidal lamp for irradiating the electrode with a germicidal wire is provided.
In the present invention, at least a part of the electrode may be composed of a photocatalyst.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention has been made based on the following five findings.
That is, (1) fungi in the air are collected by a filtration mechanism using a filter or fiber, but grow on the surface, which is a practical problem.
(2) Fungi in the air have a slight charge and are collected by the electrodes. However, in normal electrode materials and shapes, they grow on the surface, which is a practical problem.
(3) For the above problem, when the sterilization line (254 nm) is irradiated with a net-like or linear electrode, fungi in the air are collected and simultaneously sterilized (sterilized) by the sterilization line. This is a practically preferable form. The reason for using the net-like or linear electrode here is to effectively irradiate the germicidal line from the germicidal lamp to sterilize the collected fungi on the electrode.
(4) When a photocatalyst is added or integrated on the electrode, the photocatalyst exhibits a photocatalytic action, and the bactericidal effect becomes more effective.
(5) In the collection of fungi in the air on the electrode, if the fungus to be sterilized is charged in advance by photoelectrons and / or ions by discharge (applying a large amount of charge), the fungus is transferred onto the electrode of the fungus. This improves the collection effect.
[0006]
Next, the present invention will be described in detail for each configuration.
First, the electrode will be described. The shape may be any sterilization line (254 nm) emitted from the germicidal lamp as long as it irradiates the entire electrode, and there are net-like (fibrous), linear, grid-like, etc. Of these, mesh and linear are preferred because of their high effects. The material may be any material that can form an electric field as an electrode, and examples include SUS, Cu—Zn, Al, and W.
The aperture ratio between the electrode and the space (the ratio of the electrode material to the space area, in the case of a flat surface, the ratio of the area of the electrode material and the area between the electrodes) is sufficient if ultraviolet rays reach the electrode through the space. Depending on the UV-resistant irradiation intensity of the bacteria, a preliminary test can be performed as appropriate.
Usually, the aperture ratio is an area ratio of the space to the electrode material area, and is 0.3 to 20, preferably 1 to 10.
The electric field at the electrode may be an electric field for collecting fungi, and can be determined by conducting a preliminary test as appropriate. Usually 500 to 3000 V / cm.
[0007]
The photocatalyst is integrated on the electrode (arranged on the same surface) and collected on the electrode by irradiation of germicidal rays (ultraviolet rays) (virus, bacteria, yeast, mold, virus, gram-negative bacteria, gram Any one may be used as long as it can sterilize (sterilize positive bacteria, etc.) and microorganisms.
There are the following four methods for integrating the photocatalyst on the electrode.
(1) Addition of photocatalyst material on electrode material,
(2) Addition of electrodes to the photocatalyst material
(3) Mixing of electrode material and photocatalyst material, or multilayering (4) Use of photocatalyst material (Ti oxidation) as an electrode,
[0008]
A photocatalyst is usually preferable because a semiconductor material is effective, easily available, and has good processability. From the aspect of effect and economy, Se, Ge, Si, Ti, Zn, Cu, Al, Sn, Ga, In, P, As, Sb, C, Cd, S, Te, Ni, Fe, Co, Ag, Any of Mo, Sr, W, Cr, Ba, and Pb, or a compound, alloy, or oxide thereof is preferable. These are used alone or in combination of two or more.
For example, the elements Si, Ge, Se, AlP as compounds, AlAs, GaP, AlSb, GaAs , InP, GaSb, InAs, InSb, CdS, CdSe, ZnS, MoS 2, WTe 2, Cr 2 Te 3, MoTe , Cu ₂ S, WS ₂ , oxides include TiO ₂ , Bi ₂ O ₃ , CuO, Cu ₂ O, ZnO, MoO ₃ , InO ₃ , Ag ₂ O, PbO, SrTiO ₃ , BaTiO ₃ , Co ₃ O _4. , Fe ₂ O ₃ , NiO, and the like.
[0009]
Since Ti and Zn can be used as a photocatalyst, for example, by oxidizing reticulated Ti, it can be suitably used depending on the type of use destination. Further, such a material can be used as an electrode, so that it is preferable depending on the use destination.
The method for fixing (adding) the photocatalyst to the electrode material is a known addition method such as a vapor deposition method, a sputtering method, a sintering method, a sol-gel method, a coating method, or a baking coating method on an appropriate material (electrode material). Can be used as appropriate. As the additional shape, a thin film shape, a linear shape, a net shape, a strip shape, a comb shape, a granular shape, an island shape, or the like can be appropriately selected and used depending on the type of the electrode material.
As an example of the immobilization of the photocatalyst, the photocatalyst may be coated on the surface of a known conductive material as a base material, such as SUS, Cu—Zn, or Al, or may be used by being wrapped or sandwiched. As an example, there is a coating of titanium dioxide on a SUS material by a sol-gel method.
[0010]
Further, in order to improve the photocatalytic action, a substance such as Pt, Ag, Pd, RuO ₂ , or Co ₃ O ₄ can be added to the photocatalyst. The addition of the substance is preferable because the photocatalytic action is promoted. These can be used alone or in combination. Usually, the addition amount is 0.01 to 10% by weight with respect to the photocatalyst, and an appropriate concentration can be selected by conducting a preliminary test depending on the kind of the additive substance and the required performance.
As the addition method, known means such as an impregnation method, a photoreduction method, a sputter deposition method, and a kneading method can be appropriately used.
Irradiation of the sterilization line (254 nm) to the electrode material can be performed by appropriately installing a known sterilization lamp (mercury lamp) in the vicinity of the electrode material.
[0011]
Next, a method using photoelectrons for imparting charges to the fungi (charging) will be described.
The inventors of the present invention have previously made many proposals regarding charging of fine particles (particulate matter) by photoelectrons (eg, Japanese Patent Publication No. 3-5857, Japanese Patent Publication No. 6-34941, Japanese Patent Publication No. 8-221). They can be used as appropriate.
Since fungi can be regarded as particulate matter, they are similarly effectively charged by the photoelectrons. Photoelectrons are emitted by irradiating the photoelectron emitting material with ultraviolet rays.
[0012]
Each configuration for emitting the photoelectrons will be described.
The photoelectron emitting material may be any material as long as it emits photoelectrons upon irradiation with ultraviolet rays, and the smaller the photoelectric work function, the better. From the viewpoint of effect and economy, Ba, Sr, Ca, Y, Gd, La, Ce, Nd, Th, Pr, Be, Zr, Fe, Ni, Zn, Cu, Ag, Pt, Cd, Pb, Al, C, Mg, Au, In, Bi, Nb, Si, Ta, Ti, Any of U, B, Eu, Sn, P, and W or a compound or alloy thereof is preferable, and these are used alone or in combination of two or more. As the composite material, a physical composite material such as amalgam can also be used.
Oxide as a compound, boride, there are carbides, BaO in the _{oxide, SrO, CaO, Y 2 O} 5, Gd 2 O 3, Nd 2 O 3, ThO 2, ZrO 2, Fe 2 O 3, ZnO , CuO, Ag ₂ O, La ₂ O ₃ , PtO, PbO, Al ₂ O ₃ , MgO, In ₂ O ₃ , BiO, NbO, BeO, etc., and borides include YB ₆ , GdB ₆ , LaB _5. , NdB ₆ , CeB ₆ , EuB ₆ , PrB ₆ , ZrB _{2, and the} like, and examples of carbides include UC, ZrC, TaC, TiC, NbC, and WC.
[0013]
Further, as the alloy, brass, bronze, phosphor bronze, an alloy of Ag and Mg (Mg is 2 to 20 wt%), an alloy of Cu and Be (Be is 1 to 10 wt%), and an alloy of Ba and Al are used. The alloy of Ag and Mg, the alloy of Cu and Be, and the alloy of Ba and Al are preferable.
These substances can be used in bulk (solid, plate-like) or added to an appropriate base material (support) (Japanese Patent Laid-Open No. 3-108698). For example, it is added to the surface of an ultraviolet light transmissive substance or in the vicinity of the surface (Japanese Patent Publication No. 7-93098).
Any method may be used as long as photoelectrons are emitted by irradiation with ultraviolet rays.
For example, a method of coating on a glass plate, another method of embedding in the vicinity of the surface of a plate-like substance, or a method of adding another material on the plate-like substance. And a method using a mixture of an ultraviolet light transmissive substance and a substance that emits photoelectrons. Moreover, the addition can be suitably used such as a method of adding to a thin film, a method of adding to a net, line, granule, island, or band.
[0014]
The photoelectron emitting material can be added by coating or adhering to the surface of an appropriate material by a known method. For example, an ion plating method, a sputtering method, a vapor deposition method, a CVD method, a plating method, a coating method, a stamp printing method, and a screen printing method can be used as appropriate.
The thickness of the thin film may be any thickness as long as photoelectrons are emitted by ultraviolet irradiation, and is generally 5 to 5,000 mm, and usually 20 to 500 mm. The base material can be used in a plate shape, a pleat shape, a cylindrical shape, a rod shape, a line shape, a net shape, and the like, and the surface shape can be appropriately made uneven. Also, the tip of the convex portion can be sharp or spherical (Japanese Patent Publication No. 6-74908).
For the addition of the thin film to the base material, as already proposed by the present inventor, one type or two or more types of materials can be used in a single layer or in multiple layers. That is, a plurality of thin films can be used as appropriate (composite) to form a double structure or a multiple structure of more.
[0015]
These optimum shapes, types of materials that emit photoelectrons by ultraviolet irradiation, addition methods, and thin film thicknesses are the equipment, types, scales, shapes, types of photoemissive substances, types of base materials, types of photocatalysts, Preliminary tests can be performed as appropriate based on strength, application, effects, and economy.
Examples of ultraviolet rays for irradiating the photoelectron emitting material include germicidal lamps, black lights, xenon lamps, fluorescent chemical lamps, and UV-B ultraviolet lamps. This sterilizing lamp has a sterilizing action and is preferable because the sterilizing action of the present invention becomes more complete.
Further, when the photoelectron emitting material is irradiated with ultraviolet rays in an electric field, photoelectrons are effectively generated from the photoelectron emitting material.
The method for forming the electric field can be appropriately selected depending on the shape, structure, application field, expected effect (accuracy) of the charged portion, and the like. The strength of the electric field (electric field) can be determined as appropriate depending on the type of the photoelectron emitting material, and there is another invention of the present inventor. The strength of the electric field is generally 0.1 V / cm to 2 kV / cm.
The electrode material and its structure may be those used in a normal charging device. For example, a tungsten wire or a rod is used as the electrode material.
[0016]
Next, the charging of fungi due to discharge will be described.
Charging by discharge can be carried out by generating ions by discharge and imparting the ions to fungi (charging).
As an ion generation method by discharge, known methods such as corona discharge, glow discharge, arc discharge, spark discharge, creeping discharge, pulse discharge, high frequency discharge, laser discharge, trigger discharge, plasma discharge and the like can be used.
Creeping discharges and pulsed discharges are preferable depending on the application because the device is compact because the ion concentration is high. Of these, corona discharge is preferable in terms of simplicity, operability, and effects.
As the selection of generated ions, those in which the coexistence of ozone is not preferable can be used by generating positive ions by a positive corona voltage. That is, ozone is more likely to be generated in negative corona discharge than in positive.
For use in the vicinity of humans, ozone generation is not good for health, and therefore positive ions are preferably used.
[0017]
On the other hand, negative ions can be used when ozone may coexist in industrial use. In general, negative ions are preferable for use where ozone may coexist because they can be charged industrially effectively due to their higher mobility than positive ions.
Discharge electrodes and counter electrodes used for discharge can be made of known materials and shapes, and are combined with electrodes of appropriate shapes such as oblique, plate, net, linear, spherical, uneven, pleated, and comb. Can be used.
The applied voltage of corona discharge is generally 1 kV to 80 kV.
The removal of the fungi of the present invention is characterized in that the treatment gas can be treated without using a fan.
That is, (1) a method in which a processing gas is ventilated by the temperature difference between the upper and lower sides of the apparatus generated by sterilization lamp irradiation, and (2) if there is an airflow at the processing destination, the apparatus is installed in the airflow. The method (this device has no pressure loss and can be treated with a slight airflow installation) can be used.
[0018]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example at all.
Example 1
FIG. 1 is an explanatory diagram showing air cleaning of a hospital room 1 in a hospital.
In FIG. 1, particulate matter 2 containing fungi (yellow grape strains, Bacillus subtilis, mold fungi) is collected and removed by the fungus removal apparatus (air purifier) A of the present invention, and the air in the room 1 is To be cleaned.
In the hospital room 1, fungi 2 are generated from a person (sick person) 3 and its surroundings. Although this example is a case of a single room, especially when a plurality of people are hospitalized in one room, a problem of nosocomial infection (infecting another person with bacteria) occurs due to bacteria generated from the person.
In the hospital room, dust (so-called dust) 4 is generated in addition to the fungi, and is contaminated by these.
These contaminants (fungi and dust) 2 and 4 are collected and removed by the fungus removal apparatus A of the present invention whose structure is shown in FIG.
[0019]
Next, the removing apparatus A will be described with reference to FIG.
The removal device A, the sterilizing lamp 5 at the center, its around are arranged a SUS electrode 6 of reticulated, the contamination which has entered from the inlet 7 _-1, contaminants catching on the electrode 6 in particular having a charge And the outlet 7 _-2 provides clean air. This electrode 6 is formed with an electric field, so that the charged fungi (usually fungi have a negative charge) and the dust in the sick room (usually about 40 to 60% of the dust in the sick room has a charge. Is effectively collected and removed.
The fungi collected on the electrode 6 are killed by irradiation with a nearby sterilization lamp (main wavelength: 254 nm sterilization line).
[0020]
The arrows 7 ₋₁ , 7 ₋₂ , and 7 ₋₃ in FIG. 1 indicate the temperature difference (heat) between the upper and lower sides of the fungus removal apparatus A of the present invention caused by irradiation of the ultraviolet lamp (sterilization lamp) 5 in the circumferential direction. ) Caused by the air flow. By the flows 7 _-1 , 7 _-2 , and 7 _-3 , the contaminants 2 and 4 in the hospital room 1 are conveyed to the removal device A by a gentle circulation flow and are sequentially processed.
Thus, by surrounding the sterilizing lamp 5 with the mesh electrode 6 and forming an integrated (unitized) structure, the aesthetic appearance is good and natural circulation 7 ₋₁ , 7 ₋₂ , generated by ultraviolet irradiation is obtained. _7-3 effectively removes contaminants in the hospital room.
The resulting clean air 7 _-2 was freed (sterilized) of airborne fungi, microorganisms 2 and dust 4, and became sanitized air safe for humans (sick people).
In FIG. 2, 8 indicates an outer frame.
[0021]
Example 2
In Example 1, the mesh electrode 6 of FIG. ₂ was made of mesh TiO ₂ . The TiO ₂ is produced by firing a Ti material at 1000 ° C. and exhibits a photocatalytic action when irradiated with ultraviolet rays.
In this example, the electrode material 6 also serves as a photocatalyst, and the fungus collected on the electrode undergoes a photocatalytic action together with the irradiation of the sterilization line, and sterilization (sterilization) becomes complete.
This example is effective for fields of use where there are many fungi having excellent UV resistance such as Bacillus subtilis and fungi (which are difficult to sterilize simply by sterilization irradiation).
[0022]
Example 3
FIG. 3 shows a case in which the contaminants 2 and 4 are preliminarily charged with photoelectrons (multiple charges) when the contaminants 2 and 4 are collected by the mesh electrode 6 in the removal apparatus A of the first embodiment. .
The fungus removal apparatus A according to the present invention shown in FIG. 3 includes a photoelectron emitting material 9, an electric field forming electrode 10 for photoelectron emission, a charged part (B _-1 ) of contaminants composed of an ultraviolet lamp 11, and a net-like SUS product. It comprises a charged substance collecting part (B _-2 ) comprising an electrode 6 and a germicidal lamp 5.
In other words, contamination of the inlet air 7 in _-1 2,4 is charged by photoelectrons 12 to be emitted by the ultraviolet radiation from the ultraviolet lamp 11 to the photoelectron emitting member 9 (receive more charge, the multi-charged), It becomes a multi-charged charged contaminant 13. Next, the charged contaminant 13 is collected by the rear mesh electrode 6, and clean air _7-2 is obtained at the outlet. Although there is little charge due to the natural phenomenon of fungi (usually charge number 1 to 3), as described above, by applying charge by photoelectrons (multiple charge, for example, 5 to 10 charge number), fungi are collected. Become complete.
Here, various fungi and microorganisms collected on the electrode 6 are sterilized by being irradiated with ultraviolet rays from an ultraviolet lamp (sterilization lamp: main wavelength 254 nm) 5. Thus, it is one of the features of the present invention that safe sterilization air can be easily obtained.
[0023]
Example 4
In Example 3, the mesh electrode 6 of FIG. 3 was made of mesh TiO ₂ . The TiO ₂ is produced by firing a Ti material at 1000 ° C. and exhibits a photocatalytic action when irradiated with ultraviolet rays.
In this example, the electrode material 6 also serves as a photocatalyst, and the fungi collected on the electrode are completely sterilized (sterilized) by receiving a photocatalytic action together with the irradiation of the sterilization line.
This example is effective for fields of use where there are many fungi having excellent UV resistance such as Bacillus subtilis and fungi (which are difficult to sterilize simply by sterilization irradiation).
[0024]
Example 5
In the hospital, the model of the hospital room shown in FIG. 1 was created, the fungus removal apparatus A of the present invention shown in FIG. 3 was installed, the fungi were collected and removed, and airborne bacteria in the hospital room were examined.
1) Size of hospital room; 15m ³
2) Conditions of fungus removal device (1) Size of the device; about 30 liters,
(2) Fungal collection part (B- ₂ );
(1) Electrode material: Reticulated TiO ₂ was fired at 1000 ° C.
(2) Electric field: 600V / cm,
(3) Sterilization lamp: 10 W (main wavelength 254 nm),
(3) Charged part (B _-1 ) to the contaminants in advance by photoelectrons;
(1) Photoelectron emitting material: Cu-Zn plate plated with Au.
▲ 2 ▼ UV lamp; Sterilization lamp 5W,
(3) Electric field; Electrode emission electrode material Cu-Zn, 100 V / cm,
3) Measuring method of airborne bacteria; Falling bacteria method
Result A petri dish of agar medium was placed in the central part of the hospital room and at a total of five places on the left and right sides, and the falling bacteria were collected (1 hour), then cultured, and the number of colonies was observed.
The result is shown in FIG.
In FIG. 4, -o- indicates the number of colonies in the case where only the fungus collection part is operated, and-◎-indicates the number of colonies when pre-charging with photoelectrons is performed for fungus collection. Moreover,-●-is a case where there is no operation of the removal device of the present invention for comparison. The number of colonies in FIG. 4 indicates an average value at five measurement locations.
Three months after the test, the collected substance on the electrode of the fungal collecting part was cultured on an agar medium, but no colony appeared.
[0026]
Next, as a comparison, a reticulated SUS electrode was tested and examined in the same manner, and 1 to 2 colonies appeared.
Further, in the case where no sterilization lamp was irradiated in the above, the same number of colonies (at least 100 or more) appeared.
That is, this indicates that when fungi are collected using a mesh electrode under irradiation of the sterilizing lamp of the present invention, the fungi are killed on the electrode.
Further, the ozone concentration in the outlet air of the removal device A was measured (measuring instrument: chemiluminescent ozone concentration meter) at the same level (<0.01 ppm) as the inlet air, and no ozone generation was observed. .
[0027]
【The invention's effect】
As described above, by installing the fungus removal apparatus of the present invention in a space where fungi exist, such as a hospital, the following effects were produced.
(1) Airborne fungi in the air were collected and removed on the electrode, and fungi on the electrode were sterilized (sterilized). The coexisting particulate matter was also removed at the same time.
(2) In the above, by integrating the electrode material with the photocatalyst, the above bactericidal effect becomes more effective.
(3) The collection efficiency of the above-mentioned fungi and particulate matter was improved by precharging the fungi in the air by photoelectron or discharge in the collection by the above electrodes.
[0028]
(4) As mentioned above, because it is fanless, it creates a safe and clean space that effectively removes fungi without noise (prevents contamination of people, foods, plants by fungi, microorganisms, viruses, etc.) did it.
(5) By the above, it became the cleansing method of the space where the beauty was excellent.
(6) The device of the present invention is a simple fanless device having a basic configuration composed of an ultraviolet lamp and electrodes, as compared with a conventional purifier that forcibly vents contaminated air with a fan.
In addition, since sterilized air (gas) can be obtained without ozone, the applicable range has been expanded and the practicality has been improved.
And it became the practically effective sterilization space creation technique by the above.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a hospital room in a hospital in which a removal apparatus of the present invention is installed.
2A is an enlarged configuration diagram showing an example of a removing device A in FIG. 1, and FIG. 2A is a plan view, and FIG. 2B is a front view.
FIGS. 3A and 3B are an enlarged configuration diagram showing another example of the removing device A of FIG. 1A, and FIG.
FIG. 4 is a graph showing changes in the number of colonies (number) according to the number of elapsed days showing the processing results.
[Explanation of symbols]
1: Patient room, 2: Particulate matter containing fungi, 3: Person (sick), 4: Dust, 5: Disinfection lamp, 6: Electrode, 7 _-1 : Inlet airflow, 7 _-2 : Outlet airflow, 8: Outside Frame: 9: Photoelectron emitting material, 10: Electrode for electric field formation, 11: Ultraviolet lamp, 12: Photoelectron, 13: Charged contaminant, A: Removal device, B _-1 : Charged part of contaminant, B _-2 : Charging Material collector

Claims (4)

In the method of removing fungi in the air without charging, the air to be sterilized is passed through an electrode provided with an electric field of 500 to 3000 V / cm provided in a net-like or linear shape irradiated with a sterilizing wire. A method for removing fungi in the air characterized by the above.   2. The method for removing fungi in air according to claim 1, wherein the electrode has a photocatalyst. In an apparatus for removing fungi in the air without charging , a net-like or linear electrode having an electric field of 500 to 3000 V / cm applied to a flow path for air to be sterilized, and a sterilization wire to the electrode An apparatus for removing fungi in the air, characterized in that a germicidal lamp for irradiating the surface is provided.   The device for removing fungi in air according to claim 3, wherein at least a part of the electrode is composed of a photocatalyst.

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