JPS6397247A - Method and device for cleaning air by ultraviolet ray irradiation - Google Patents

Abstract

PURPOSE:To increase the irradiation efficiency of UV rays by projecting UV rays on a photoelectron emitting material through an optical fiber to charge the fine particles in the air by the emitted photoelectron, and then removing the charged fine particles from the air. CONSTITUTION:The air having about 10,000 cleanliness factor in a clean room 1 is sucked by the fan in a fan part 8 in a clean bench 11. UV rays are emitted in an UV ray irradiation part 9, and the fine particles in the air are charged. The microbes such as viruses and bacteria are simultaneously sterilized, then the charged fine particles are removed by a filter 10, and high cleanliness can be kept on a working bench 13. The charge and discharge of instruments, products, etc., to and from the working bench 13 in the clean bench 11 are carried out by the movable shutter 12 provided to the clean bench 11.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the electronic industry, pharmaceutical industry, food industry, agriculture and forestry industry,
The present invention relates to air cleaning methods and devices for clean rooms, clean booths, clean tunnels, clean benches, safety cabinets, sterile rooms, pass boxes, sterile air curtains, clean tubes, etc. in the medical and precision machinery industries.

[Conventional technology]

Conventional indoor air purification methods and devices can be roughly divided into: (1) Mechanical filtration methods (for example, HEPA filters) (2) Filtration using high-voltage charged and conductive filters that electrostatically collect particulates method (e.g. M
ESA filter), but each of these methods had the following drawbacks.

In other words, in the mechanical filtration method, it is necessary to use an a-mesh filter in order to improve the air cleanliness (class), but in this case the pressure loss is high, and the increase in pressure loss due to clogging is also significant. Not only is it difficult to maintain, manage, or replace the filter, but the filter life is short, and when replacing the filter, it is necessary to stop work during that time, and it takes a long time to recover. However, it had the disadvantage of poor production efficiency.

Additionally, in order to improve the cleanliness of the air, the number of times of ventilation (the number of times air is circulated by a fan) has been increased, but this has the drawback of increasing power costs.

In addition, conventional filter methods are only intended to remove particulates, so they can be used in industrial clean rooms, but filters almost always have pinholes, which can cause some of the contaminated air to leak out. Therefore, there were limits to its use in biological clean rooms.

In addition, in the case of a method in which all particulates are collected electrostatically, a high voltage of, for example, 15 to 70 kV is required in the pre-charging section, which increases the size of the device and poses problems in terms of safety and maintenance. Ta.

In order to solve these problems, the present inventor previously proposed an air purification method using ultraviolet irradiation (Patent Application No. 60-18
No. 725).

In the ultraviolet irradiation method, c. The photoelectron emitting material must be irradiated with ultraviolet light efficiently and under simple maintenance and management.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for irradiating a photoelectron emitting material with ultraviolet rays with high efficiency in an ultraviolet irradiation method and with easy maintenance and management.

[Structure of the invention]

The present invention provides an air cleaning method in which fine particles in the air are charged with photoelectrons emitted by irradiating fi+ ultraviolet light onto a photoelectron emitting material, and then the charged fine particles are removed from the air. An air purification method characterized by irradiating a photoelectron emitting material with a photoelectron emitting material. and (2) on the air flow path from the air inlet to the air outlet, at least a source electron emitting section that irradiates ultraviolet rays from a source fiber onto the photoelectron emitting material, and a charged particle collection section on the downstream side thereof. It is an air purifying device.

Next, the present invention will be explained in detail based on the drawings.

FIG. 3 is a schematic diagram of a clean bench combination method in a biological clean room, that is, a method in which only a part of the working area is kept at a high level of cleanliness.

FIG. 1 is a schematic diagram showing an embodiment of the ultraviolet irradiation section.

In FIG. 3, inside the clean room 1, after filtering the coarse particles of the outside air introduced from the pipe 2 with a pre-filter 6, a fan 5 is installed together with the air taken out from the air outlet 4 of the clean room 1. After the temperature and humidity are adjusted in the air conditioner 6 through the air conditioner 6, the air from which particulates have been removed by the HEPA filter P-7 is circulated and supplied, and the cleanliness (
class) is maintained at around 10,000.

On the other hand, a clean bench 11 provided with a fan section 8, an ultraviolet irradiation section 9, and a charged particle collection section 10 in the clean room 1
The workbench 13 inside is maintained in a sterile atmosphere of high cleanliness (class 10).

That is, in the clean bench 11, the air in the clean room 1 with a cleanliness level (class) of about 10,000 is sucked by the fan in the fan unit 8, and the ultraviolet rays are irradiated in the ultraviolet irradiation unit 9 to eliminate fine particles in the air. are charged and microorganisms such as viruses, bacteria, yeast, and mold are sterilized, and then the charged particulates are removed by the filter 10, thereby maintaining a high level of cleanliness on the workbench 13.

Instruments, products, etc. are taken in and out of the workbench 15 in the clean bench 11 using a movable shutter 12 provided on the clean bench 11.

The ultraviolet irradiation section 9, as shown in a schematic diagram in FIG. When the original fiber 20 is irradiated with ultraviolet rays from an ultraviolet lamp 22 installed outside the clean bench 11 on the surface of the photoelectron emitting material, the particles in the air 23 are efficiently charged by the photoelectrons emitted.

The type of ultraviolet rays may be any type as long as the photoelectron emitting material can emit photoelectrons when irradiated with the ultraviolet rays, but it is preferable to use ultraviolet rays that also have a bactericidal effect.

Laws can be established as appropriate depending on the field of application, content of work, purpose, economic efficiency, etc. For example, in the biological field, it is preferable to use deep ultraviolet rays together in terms of bactericidal action and efficiency.

The ultraviolet light in this example is ultraviolet light from a deuterium lamp, and the ultraviolet lamp 22 is schematically shown in FIG.

The electrode consists of a cathode 24, an anode 25, and a shielding box 26 surrounding both, the outer container is quartz glass 27, the window is ultraviolet-transmitting glass 28, and the tube is filled with several torr of highly pure deuterium gas. .

Reference numeral 29 indicates the original axis, which indicates the traveling direction of the ultraviolet rays from the ultraviolet lamp.

The ultraviolet light from the ultraviolet lamp is irradiated through a source fiber bundle 30 made up of a plurality of source fibers outside the clean bench 11. The ultraviolet light m of the original fiber bundle passes through the original fibers and is irradiated onto the photoelectron emitting material 21 by each original fiber 20 inside the clean bench 11 .

The photoelectron emitting material 21 is normally irradiated with ultraviolet light by the original fiber 20 at Q, 56n to 55nm per optical fiber.
The irradiation is performed using circular spot irradiation with a diameter of approximately cPn.

Therefore, the original fibers 2 constituting the original fiber bundle 30
The number of 0's can be determined as appropriate depending on the area of the photoelectron emitting material 21 and the area of spot irradiation.

The source fiber may be of any type as long as it can efficiently irradiate the photoelectron emitting material 21 with the ultraviolet rays from the ultraviolet lamp 22. Types of original fibers include glass fibers, quartz fibers, and plastic fibers, but quartz fibers are preferred for the above purpose.

The diameter of each optical fiber constituting the bundled original fiber 30 is 10 μm to 20 m+, and can be appropriately selected depending on the method of introducing ultraviolet rays from an ultraviolet lamp, mechanical strength, irradiation area by the original fiber, etc.

The preferred diameter per optical fiber is (L1~1
It is 0 ■.

Introducing ultraviolet rays into the original fiber can be carried out by irradiating the original fiber bundle 30 with ultraviolet rays from an ultraviolet lamp 22 or by irradiating the original fiber bundle 30 with ultraviolet rays through a condensing lens or a curved condenser. This can be done by various methods.

The method of introducing ultraviolet rays into the original fiber can be determined as appropriate depending on the type, model, shape of the ultraviolet lamp, the type, shape, effect, etc. of the original fiber.

Next, the photoelectron emitting material 21 may be any material as long as it emits photoelectrons when irradiated with ultraviolet rays, and the smaller the photoelectric work function, the more preferable it is. From the viewpoint of effectiveness and economy, Ba, Sr, Ca, Y,
Gd, La, Co.

Nd, Th, Pr, Be, Zr,
Fe, Ni, Zn, Cu, Ag.

Pt, Cd, Pb, At, C, Mg, A
u, In, Bi, Nb, Si.

Any one of Ti, Ta, Sn, and P or a compound or alloy thereof is preferred, and these may be used alone or in combination of two or more. As the composite material, a physical composite material such as amalgam can also be used.

For example, compounds include oxides, ferrides, and carbides, and oxides include BaO, SrO, and YzO@.

Gd403, Nd403, Th02, Zr
01, Fe103, ZnO, CuO.

Agz○, pto, pb○, Al40B,
MgO, In2O,, BiO, N1)O.

There are BeO, etc., and borides include YBs and Gd.
E.

LaB5, CeB6, PrB6, Z! ”B
! etc., and carbides such as ZrC, TaC,
Examples include TiC and NbC.

In addition, alloys include brass, bronze, and phosphor bronze.

An alloy of Ag and Mg (2 to 20 wt% Mg), an alloy of Cu and Be (1 to 10 wt% Be), and an alloy of Ba and At can be used; An alloy of Cu and Be and an alloy of Ba and At are preferred. For oxides, only the metal surface is heated in air,
Alternatively, it can be obtained by oxidizing with chemicals.

Still another method is to heat the material before use to form an oxidized layer on the surface to obtain a stable oxidized layer over a long period of time. As an example of this, a thin oxide film can be formed on the surface of an alloy of Mg and Ag in water vapor at a temperature of 500 to 400 DEG C., and this thin oxide film is stable for a long period of time.

These materials may be used in any shape, such as a plate, pleats, or net, but they require a large area of ultraviolet irradiation and contact with air! A net-like shape is preferable from this point of view.

101 To explain Clean Pente 11 based on Figure 1, 31
is the air sucked in by the fan 8 from the clean room, and relatively coarse particles in the sucked air are collected and removed by the coarse filter 32 in advance.

The particles in the air 23 from which relatively coarse particles have been removed are:
As described above, due to the action of photoelectrons emitted from the photoelectron emitting material 21 irradiated with ultraviolet rays by the original fiber 20,
Charged efficiently.

Also, microorganisms in the air are sterilized by ultraviolet energy here.

Charged particles, including dead organisms, are collected by electrostatic filter 10. Any collector for charged particles may be used. One type of dust collection plate (dust collection electrode) and electrostatic filter in a normal charging device is common, but a structure in which the collection part itself constitutes an electrode, such as a steel wool electrode, is also effective. One-type electrostatic filters are effective in terms of ease of handling, performance, and economy, but
Since clogging occurs after use for a certain period of time, stable operation can be achieved over a long period of time by using a cartridge structure as necessary and replacing the valve by detecting pressure loss. 53 is highly clean (class 10) sterile air.

〔Effect of the invention〕

1. By irradiating the photoelectron emitting material with ultraviolet rays from the ultraviolet emitting part through the source fiber, (1) the photoelectron emitting material can be efficiently irradiated with ultraviolet rays.

a) Effective irradiation corresponding to the distribution of fine particles (distribution of flow) is possible.

b) Effective irradiation corresponding to the shape of the photoelectron emitting material is possible.

2. By installing the ultraviolet light emitting unit (UV rung) outside the clean room equipment (eg, clean bench), maintenance management has become easier, such as the ease of changing the ultraviolet lamp when it reaches the end of its life.

■ When UV lamps are installed inside a clean bench, there is a need for improvement because there is contamination from the outside when the UV lamps are replaced and dust is generated near the UV lamp installation area. Contamination from the vicinity has disappeared.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram for explaining the device of the present invention, Fig. 2 is a schematic diagram of the ultraviolet emitting unit used in the present invention, and Fig. 3 is a schematic diagram for explaining an air purifying device combined with a clean bench in a biological clean room. FIG. 1...Clean room, 3...Pre-filter, 6.
・・Air conditioner, 7・HEPA filter, 8・
...Fan part, 9...Ultraviolet irradiation part, 10...Charged particulate collection part, 11...Clean bench, 13--Working table, 20... Original fiber, 21... Photoelectron emission material , 22... Ultraviolet lamp, 24... Cathode, 25.
...anode, 26...shielding box, 27...outer container,
29... Original axis, 30... Original fiber bundle, 61...
・Air, 32... Coarse filter patent applicant: Ebara Research Institute, Ltd. Ebara Corporation

Claims (1)

[Claims] 1. In an air cleaning method in which fine particles in the air are charged with photoelectrons emitted by irradiating ultraviolet rays onto a photoelectron emitting material, and then the charged fine particles are removed from the air, An air purification method characterized by irradiating a photoelectron emitting material with an optical fiber. 2. The method according to claim 1, wherein the optical fiber is a quartz fiber. 3. Claim 1 or 2 which uses a bundle of optical fibers each having a diameter of 0.1 to 10 mm.
The method described in section. 4. An air cleaning device comprising a photoelectron emitting section that irradiates ultraviolet rays through an optical fiber onto at least a photoelectron emitting material on an air flow path from an air inlet to an air outlet, and a charged particle collection section on the downstream side thereof.